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Sample records for sublethal effects erod

  1. Effects of human pharmaceuticals on cytotoxicity, EROD activity and ROS production in fish hepatocytes

    International Nuclear Information System (INIS)

    Laville, N.; Aiet-Aiessa, S.; Gomez, E.; Casellas, C.; Porcher, J.M.

    2004-01-01

    Pharmaceuticals are found in the aquatic environment but their potential effects on non-target species like fish remain unknown. This in vitro study is a first approach in the toxicity assessment of human drugs on fish. Nine pharmaceuticals were tested on two fish hepatocyte models: primary cultures of rainbow trout hepatocytes (PRTH) and PLHC-1 fish cell line. Cell viability, interaction with cytochrome P450 1A (CYP1A) enzyme and oxidative stress were assessed by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrasodium bromide tetrazolium (MTT), 7-ethoxyresorufin-o-deethylase (EROD) and dichlorofluorescein (DCFH-DA) assays, respectively. The tested drugs were clofibrate (CF), fenofibrate (FF), carbamazepine (CBZ), fluoxetine (FX), diclofenac (DiCF), propranolol (POH), sulfamethoxazole (SFX), amoxicillin (AMX) and gadolinium chloride (GdCl 3 ). All substances were cytotoxic, except AMX at concentration up to 500 μM. The calculated MTT EC 50 values ranged from 2 μM (CF) to 651 μM (CBZ) in PLHC-1, and from 53 μM (FF) to 962 μM (GdCl 3 ) in PRTH. CF, FF, and FX were the most cytotoxic drugs and induced oxidative stress before being cytotoxic. Compared to hepatocytes from human and dog, fish hepatocytes seemed to be more susceptible to the peroxisome proliferators (PPs) CF and FF. In PLHC-1 cells none of the tested drugs induced the EROD activity whereas POH appeared as a weak EROD inducer in PRTH. Moreover, in PRTH, SFX, DiCF, CBZ and to a lesser extend, FF and CF inhibited the basal EROD activity at clearly sublethal concentrations which may be of concern at the biological and chemical levels in a multipollution context

  2. Pesticides and Arthropods: Sublethal Effects and Demographic Toxicology

    Directory of Open Access Journals (Sweden)

    Dejan Marčić

    2007-01-01

    Full Text Available Insecticides and acaricides designed to control primary harmful insects and mites may also variously affect some other arthopods present in an (agroecosystem (e.g. secondary pests, predators, parasitoids, saprophytes, bioindicators, pollinators. Apart from insecticides and acaricides, arthropods may also be affected by the activity of other pesticides (fungicides, herbicides, etc.. Regardless of whether they are deemed desirable or not, the effects that pesticides have on arthopods need to be quantified as closely as possible through appropriate experimental procedures. Data acquired in tests designed to determined LD50/LC50 values are inadequate for evaluation of pesticide effectiveness in the field as pesticidesalso cause various sublethal effects, generally disregarded in such investigations. The sublethal effects of pesticides refer to any altered behaviour and/or physiology of individuals that have survived exposure to pesticides at doses/concentrations that can be lethal(within range causing mortality in an experimental population that exceeds mortality in an untreated population or sublethal (below that range. Pesticides affect locomotion and mobility, stimulate dispersion of arthropods from treated areas, complicate or prevent their navigation, orientation and ability to locate hosts, and cause changes in their feeding, mating and egg-laying patterns. Sublethal pesticide effects on arthropod physiology reflect on the life span, rate of development, fecundity and/or fertility, sex ratio and immunity of surviving individuals. Different parameters are being used in arthropod bioassays to determine sublethal effects (ED50/EC50, LOEC, NOEC, total effect index. Compared to acute toxicity tests, these parameters improve the quality of evaluation and create a more accurate view of the effects of a pesticide. However, such approach covers mainly fecundity/fertility alone, while all other sublethal effects remain unaccounted for. Besides, it

  3. Ethoxyresorufin-O-deethylase (EROD) induction in rainbow trout exposed to diluted oil sand wastewater

    International Nuclear Information System (INIS)

    Verbeek, A.; Mackay, W.; Birkholz, D.

    1995-01-01

    Toxic industrial wastewaters, such as those from oil sands extraction, must be assessed for their potential sublethal effects before they can be safely disposed in the environment. The induction of ethoxyresorufin-O-deethylase activity was assessed as a potential bioindicator of sublethal stress in rainbow trout exposed to sublethal concentrations of oil sands tailings water. The mixed-function oxygenase system in rainbow trout responded rapidly following a definable concentration-response relationship; however, it proved to be a relatively insensitive indicator of sublethal exposure to oil sands tailings water. Increased activity and maximal induction, as a result of exposure to 0.3 and 0.6 times the LC 50 (Toxic Units), occurred rapidly within 24 hours of exposure. The linearity of the relationship between the concentration of oil sands tailings pond water and ethoxyresorufin-O-deethylase activity, expressed by the following regression equation, In EROD = 3.68 (conc.) + 3.20, had an r 2 value of 0.593. Maximal induction required 0.4--0.8 Toxic Units. The absolute level of maximal induction was only one-fifth to one-sixth of the potential induction as found in response to the positive control, 0.5 mg/kg β-naphthoflavone (i.p.). The authors also present data that suggests that the different levels of induction observed in trout exposed to tailings pond water vs those injected with 0.5 mg/kg β-naphthoflavone (i.p.) may be indicative of two different P450 isoforms, the CYP4Al isoform responding to the organic acidic surfactants in oil sands tailings pond water and the CYP1A1 isoform, the isoform generally associated with most xenobiotic transformation in fish, responding to β-naphthoflavone

  4. Sublethal Toxic effects of spent Oil Based Drilling Mud and Cuttings ...

    African Journals Online (AJOL)

    Sublethal toxic effects of spent oil based drilling mud collected from an abandoned oil drilling site in Mpanak, Akwa Ibom State, Nigeria were assessed in the earthworm Aporrectodea longa. The test annelid was exposed to sub-lethal Concentration of 0ppm SPP; 62,500ppm SPP; 125, 000ppm SPP; 250,000ppm SPP and ...

  5. Lethal and Sublethal Effects of Fenpropathrin on the Biological Performance of Scolothrips longicornis (Thysanoptera: Thripidae)

    DEFF Research Database (Denmark)

    Pakyari, Hajar; Enkegaard, Annie

    2013-01-01

    Determination of negative nontarget effects of pesticides on beneficial organisms by measuring only lethal effects is likely to underestimate effects of sublethal doses. In this study, the sublethal effects of fenpropathrin on the predatory thrips Scolothrips longicornis Priesner (Thysanoptera: T...

  6. The sublethal effects of zinc at different water temperatures on ...

    African Journals Online (AJOL)

    The sublethal effects of zinc at different water temperatures on selected ... of 96h at different water temperatures representing the seasonal temperatures in the ... are mobilised to meet increased energy demands during periods of stress.

  7. Host defenses in experimental scrub typhus: effect of sublethal gamma radiation

    International Nuclear Information System (INIS)

    Kelly, D.J.

    1983-01-01

    The effect of sublethal gamma radiation on inbred mice chronically infected with scrub typhus rickettsiae was examined. Inbred mice which have been inoculated with Gilliam or Karp strain of Rickettsia tsutsugamushi by the subcutaneous route harbored the infection for at least one year. Irradiation of these animals at 12 or 52 weeks post inoculation at normally sublethal levels induced a significantly higher percentage of rickettsemic mice (recrudescence) than in the unirradiated similarly infected control animals. In addition, sublethal irradiation at 12 weeks also induced a quantitative increase in total rickettsiae. Homologous antibody titers to the rickettsiae were examined for five weeks following irradiation to determine the role of the humoral response in radiation induced recrudescence. Modification of recrudescence was investigated using radioprotective drugs. The expected results of this investigation supported the conclusion that the recrudescence of a chronic rickettsial infection in the appropriate host following immunological impairment due to battlefield or clinical exposure to gamma radiation can result in an acute, possibly lethal rickettsemia

  8. Lethal and sublethal effects of imidacloprid on Osmia lignaria and clothianidin on Megachile rotundata (Hymenoptera: Megachilidae).

    Science.gov (United States)

    Abbott, V A; Nadeau, J L; Higo, H A; Winston, M L

    2008-06-01

    We examined lethal and sublethal effects of imidacloprid on Osmia lignaria (Cresson) and clothianidin on Megachile rotundata (F.) (Hymenoptera: Megachilidae). We also made progress toward developing reliable methodology for testing pesticides on wild bees for use in pesticide registration by using field and laboratory experiments. Bee larvae were exposed to control, low (3 or 6 ppb), intermediate (30 ppb), or high (300 ppb) doses of either imidacloprid or clothianidin in pollen. Field experiments on both bee species involved injecting the pollen provisions with the corresponding pesticide. Only O. lignaria was used for the laboratory experiments, which entailed both injecting the bee's own pollen provisions and replacing the pollen provision with a preblended pollen mixture containing imidacloprid. Larval development, emergence, weight, and mortality were monitored and analyzed. There were no lethal effects found for either imidacloprid or clothianidin on O. lignaria and M. rotundata. Minor sublethal effects were detected on larval development for O. lignaria, with greater developmental time at the intermediate (30 ppb) and high doses (300 ppb) of imidacloprid. No similar sublethal effects were found with clothianidin on M. rotundata. We were successful in creating methodology for pesticide testing on O. lignaria and M. rotundata; however, these methods can be improved upon to create a more robust test. We also identified several parameters and developmental stages for observing sublethal effects. The detection of sublethal effects demonstrates the importance of testing new pesticides on wild pollinators before registration.

  9. Sublethal effects of some synthetic and botanical insecticides on Bemisia tabaci (Hemiptera: Aleyrodidae

    Directory of Open Access Journals (Sweden)

    Esmaeily Saeideh

    2014-07-01

    Full Text Available In addition to direct mortality caused by insecticides, some biological traits of insects may also be affected by sublethal insecticide doses. In this study, we used the age-stage, two-sex life table method to evaluate the sublethal effects of the four synthetic insecticides: abamectin, imidacloprid, diazinon, and pymetrozin as well as the botanical insecticide taken from Calotropis procera (Asclepiadaceae extract, on eggs of the cotton whitefly, Bemisia tabaci (Hem.: Aleyrodidae. The lowest and highest survival rates and oviposition periods were observed in whiteflies treated by diazinon and imidacloprid, respectively. We found significant differences in the net reproductive rate (R0, the intrinsic rate of increase (r, the finite rate of increase (?, and the gross reproductive rate (GRR among different insecticides. Altogether, our results showed that pymetrozin and C. procera induced the most sublethal effects, thus they may be suitable candidates for use in integrated pest management programs of B. tabaci.

  10. Histopathological effects of lethal and sub-lethal concentrations of ...

    African Journals Online (AJOL)

    The histopathological effects of lethal and sub-lethal concentrations of glyphosate on African catfish Clarias gariepinus were investigated. C. gariepinus juveniles were assessed in a static renewal bioassay for 96 hours (acute toxicity) and 28 days (chronic toxicity) using varying concentrations (0.0 mg/l 20.0 mg/l, 30.0 mg/l, ...

  11. Effects of sublethal doses of chlorfluazuron on the ovarian ...

    African Journals Online (AJOL)

    AJB_YOMI

    2011-10-12

    Oct 12, 2011 ... eggs (Perveen, 2000a). The objectives of this research were to determine the effects of sublethal doses of chlorfluazuron (LD10or LD30) on the amounts of ovarianprotein, lipid, carbohydrates, DNA, and RNA, and ecdysteroid titres in different developmental stages of S. litura, a major crop pest around the ...

  12. Experimental Study of Factors Affecting Soil Erodibility

    Science.gov (United States)

    Larionov, G. A.; Bushueva, O. G.; Gorobets, A. V.; Dobrovolskaya, N. G.; Kiryukhina, Z. P.; Krasnov, S. F.; Litvin, L. F.; Maksimova, I. A.; Sudnitsyn, I. I.

    2018-03-01

    The effect of different factors and preparation conditions of monofraction samples from the arable horizon of leached chernozem on soil erodibility and its relationship with soil tensile strength (STS) has been studied. The exposure of samples at 38°C reduces their erodibility by two orders of magnitude. The drying of samples, on the contrary, increases their erodibility. It has been shown that erodibility decreases during the experiment. It has been found that the inoculation of soil with yeast cultures ( Naganishia albida, Lipomyces tetrasporus) reliably increases the STS value in 1.5-1.9 times. The sterile soil is eroded more intensively than the unsterile soil: at 4.9 and 0.3 g/(m2 s), respectively. The drying of soil followed by wetting to the initial water content (30%) has no significant effect on the STS value in almost all experimental treatments.

  13. Chronic Sublethal Effects of Cantharidin on the Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae

    Directory of Open Access Journals (Sweden)

    Zhengyu Huang

    2015-05-01

    Full Text Available The diamondback moth, Plutella xylostella (Linnaeus (Lepidoptera: Plutellidae, is a major pest of cruciferous vegetables worldwide. Cantharidin, a natural toxin isolated from blister beetles, has been reported to be toxic to P. xylostella. However, little is known on the chronic sublethal effects of cantharidin on this species. In this study, we assessed the changes of susceptibility, development, reproduction and other demographic parameters in both the selected P. xylostella strain (Sub, selected by LC25 cantharidin for consecutive 12 generations and the revertant strain (SubR, derived from the Sub strain without being exposed to cantharidin for 12 generations. Results revealed that the two strains maintained a relatively high-level susceptibility to cantharidin. Severe adverse effects on the population dynamics and fitness in Sub strain were observed. In addition, repeated exposure of P. xylostella to sublethal concentration of cantharidin resulted in negative effects on adult performance and deformities in adults. Although morphologically normal for individuals, the SubR strain exhibited a disadvantage in population growth rate. Our results showed that sublethal concentration of cantharidin exhibited severe negative effects on population growth for longtime. These findings would be useful for assessing the potential effects and risk of cantharidin on P. xylostella and for developing effective integrated pest management.

  14. Chronic Sublethal Effects of Cantharidin on the Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae).

    Science.gov (United States)

    Huang, Zhengyu; Zhang, Yalin

    2015-05-29

    The diamondback moth, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), is a major pest of cruciferous vegetables worldwide. Cantharidin, a natural toxin isolated from blister beetles, has been reported to be toxic to P. xylostella. However, little is known on the chronic sublethal effects of cantharidin on this species. In this study, we assessed the changes of susceptibility, development, reproduction and other demographic parameters in both the selected P. xylostella strain (Sub, selected by LC25 cantharidin for consecutive 12 generations) and the revertant strain (SubR, derived from the Sub strain without being exposed to cantharidin for 12 generations). Results revealed that the two strains maintained a relatively high-level susceptibility to cantharidin. Severe adverse effects on the population dynamics and fitness in Sub strain were observed. In addition, repeated exposure of P. xylostella to sublethal concentration of cantharidin resulted in negative effects on adult performance and deformities in adults. Although morphologically normal for individuals, the SubR strain exhibited a disadvantage in population growth rate. Our results showed that sublethal concentration of cantharidin exhibited severe negative effects on population growth for longtime. These findings would be useful for assessing the potential effects and risk of cantharidin on P. xylostella and for developing effective integrated pest management.

  15. Chronic Sublethal Effects of Cantharidin on the Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae)

    Science.gov (United States)

    Huang, Zhengyu; Zhang, Yalin

    2015-01-01

    The diamondback moth, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), is a major pest of cruciferous vegetables worldwide. Cantharidin, a natural toxin isolated from blister beetles, has been reported to be toxic to P. xylostella. However, little is known on the chronic sublethal effects of cantharidin on this species. In this study, we assessed the changes of susceptibility, development, reproduction and other demographic parameters in both the selected P. xylostella strain (Sub, selected by LC25 cantharidin for consecutive 12 generations) and the revertant strain (SubR, derived from the Sub strain without being exposed to cantharidin for 12 generations). Results revealed that the two strains maintained a relatively high-level susceptibility to cantharidin. Severe adverse effects on the population dynamics and fitness in Sub strain were observed. In addition, repeated exposure of P. xylostella to sublethal concentration of cantharidin resulted in negative effects on adult performance and deformities in adults. Although morphologically normal for individuals, the SubR strain exhibited a disadvantage in population growth rate. Our results showed that sublethal concentration of cantharidin exhibited severe negative effects on population growth for longtime. These findings would be useful for assessing the potential effects and risk of cantharidin on P. xylostella and for developing effective integrated pest management. PMID:26035491

  16. Lethal and sublethal effects of azadirachtin on the bumblebee Bombus terrestris (Hymenoptera: Apidae).

    Science.gov (United States)

    Barbosa, Wagner Faria; De Meyer, Laurens; Guedes, Raul Narciso C; Smagghe, Guy

    2015-01-01

    Azadirachtin is a biorational insecticide commonly reported as selective to a range of beneficial insects. Nonetheless, only few studies have been carried out with pollinators, usually emphasizing the honeybee Apis mellifera and neglecting other important pollinator species such as the bumblebee Bombus terrestris. Here, lethal and sublethal effects of azadirachtin were studied on B. terrestris via oral exposure in the laboratory to bring out the potential risks of the compound to this important pollinator. The compound was tested at different concentrations above and below the maximum concentration that is used in the field (32 mg L(-1)). As most important results, azadirachtin repelled bumblebee workers in a concentration-dependent manner. The median repellence concentration (RC50) was estimated as 504 mg L(-1). Microcolonies chronically exposed to azadirachtin via treated sugar water during 11 weeks in the laboratory exhibited a high mortality ranging from 32 to 100 % with a range of concentrations between 3.2 and 320 mg L(-1). Moreover, no reproduction was scored when concentrations were higher than 3.2 mg L(-1). At 3.2 mg L(-1), azadirachtin significantly inhibited the egg-laying and, consequently, the production of drones during 6 weeks. Ovarian length decreased with the increase of the azadirachtin concentration. When azadirachtin was tested under an experimental setup in the laboratory where bumblebees need to forage for food, the sublethal effects were stronger as the numbers of drones were reduced already with a concentration of 0.64 mg L(-1). Besides, a negative correlation was found between the body mass of male offspring and azadirachtin concentration. In conclusion, our results as performed in the laboratory demonstrated that azadirachtin can affect B. terrestris with a range of sublethal effects. Taking into account that sublethal effects are as important as lethal effects for the development and survival of the colonies of B. terrestris

  17. Linking nutrient enrichment, sediment erodibility and biofilms

    Science.gov (United States)

    Conrad, B.; Mahon, R.; Sojka, S. L.

    2014-12-01

    Sediment movement in coastal lagoons affects nutrient flux and primary producer growth. Previous research has shown that sediment erodibility is affected by biofilm concentration and that growth of benthic organisms, which produce biofilm, is affected by nutrient enrichment. However, researchers have not examined possible links between nutrient addition and sediment erodibility. We manipulated nutrient levels in the water column of 16 microcosms filled with homogenized sediment from a shallow coastal lagoon and artificial seawater to determine the effects on biofilm growth, measured through chlorophyll a and colloidal carbohydrate concentrations. Erosion tests using a Gust microcosm were conducted to determine the relationship between sediment erodibility and biofilm concentration. Results show that carbohydrate levels decreased with increasing nutrient enrichment and were unrelated to chlorophyll concentrations and erodibility. The nutrient levels did not predictably affect the chlorophyll levels, with lower chlorophyll concentrations in the control and medium enrichment treatments than the low and high enrichment treatments. Controls on biofilm growth are still unclear and the assumed relationship between carbohydrates and erodibility may be invalid. Understanding how biofilms respond to nutrient enrichment and subsequent effects on sediment erodibility is essential for protecting and restoring shallow coastal systems.

  18. Toxic effects of sublethal concentrations of diethyl Phthalate on the ...

    African Journals Online (AJOL)

    An investigation on the effect of Diethyl phthalate (DEP) on the gill of the African catfish Clarias gariepinus was carried out in the laboratory. Seventy-five (75) catfish fingerlings were subjected to continuous exposure to sublethal concentrations of DEP (30, 40, 60 and 80 ìg/L) for a period of four weeks. The gills of the catfish ...

  19. RFID Tracking of Sublethal Effects of Two Neonicotinoid Insecticides on the Foraging Behavior of Apis mellifera

    Science.gov (United States)

    Schneider, Christof W.; Tautz, Jürgen; Grünewald, Bernd; Fuchs, Stefan

    2012-01-01

    The development of insecticides requires valid risk assessment procedures to avoid causing harm to beneficial insects and especially to pollinators such as the honeybee Apis mellifera. In addition to testing according to current guidelines designed to detect bee mortality, tests are needed to determine possible sublethal effects interfering with the animal's vitality and behavioral performance. Several methods have been used to detect sublethal effects of different insecticides under laboratory conditions using olfactory conditioning. Furthermore, studies have been conducted on the influence insecticides have on foraging activity and homing ability which require time-consuming visual observation. We tested an experimental design using the radiofrequency identification (RFID) method to monitor the influence of sublethal doses of insecticides on individual honeybee foragers on an automated basis. With electronic readers positioned at the hive entrance and at an artificial food source, we obtained quantifiable data on honeybee foraging behavior. This enabled us to efficiently retrieve detailed information on flight parameters. We compared several groups of bees, fed simultaneously with different dosages of a tested substance. With this experimental approach we monitored the acute effects of sublethal doses of the neonicotinoids imidacloprid (0.15–6 ng/bee) and clothianidin (0.05–2 ng/bee) under field-like circumstances. At field-relevant doses for nectar and pollen no adverse effects were observed for either substance. Both substances led to a significant reduction of foraging activity and to longer foraging flights at doses of ≥0.5 ng/bee (clothianidin) and ≥1.5 ng/bee (imidacloprid) during the first three hours after treatment. This study demonstrates that the RFID-method is an effective way to record short-term alterations in foraging activity after insecticides have been administered once, orally, to individual bees. We contribute further information on

  20. RFID tracking of sublethal effects of two neonicotinoid insecticides on the foraging behavior of Apis mellifera.

    Directory of Open Access Journals (Sweden)

    Christof W Schneider

    Full Text Available The development of insecticides requires valid risk assessment procedures to avoid causing harm to beneficial insects and especially to pollinators such as the honeybee Apis mellifera. In addition to testing according to current guidelines designed to detect bee mortality, tests are needed to determine possible sublethal effects interfering with the animal's vitality and behavioral performance. Several methods have been used to detect sublethal effects of different insecticides under laboratory conditions using olfactory conditioning. Furthermore, studies have been conducted on the influence insecticides have on foraging activity and homing ability which require time-consuming visual observation. We tested an experimental design using the radiofrequency identification (RFID method to monitor the influence of sublethal doses of insecticides on individual honeybee foragers on an automated basis. With electronic readers positioned at the hive entrance and at an artificial food source, we obtained quantifiable data on honeybee foraging behavior. This enabled us to efficiently retrieve detailed information on flight parameters. We compared several groups of bees, fed simultaneously with different dosages of a tested substance. With this experimental approach we monitored the acute effects of sublethal doses of the neonicotinoids imidacloprid (0.15-6 ng/bee and clothianidin (0.05-2 ng/bee under field-like circumstances. At field-relevant doses for nectar and pollen no adverse effects were observed for either substance. Both substances led to a significant reduction of foraging activity and to longer foraging flights at doses of ≥0.5 ng/bee (clothianidin and ≥1.5 ng/bee (imidacloprid during the first three hours after treatment. This study demonstrates that the RFID-method is an effective way to record short-term alterations in foraging activity after insecticides have been administered once, orally, to individual bees. We contribute further

  1. Lethal and sublethal effects of pesticides in the management of Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae) on Capsicum annuum L.

    Science.gov (United States)

    Breda, Mariana O; Oliveira, José V; Esteves Filho, Alberto B; Barbosa, Douglas Rs; Santos, Andrezo A

    2017-10-01

    The evaluation of lethal and sublethal effects is of great importance for a complete assessment of the total impact of chemical compounds upon pest populations and the development of management strategies. In this study, we evaluated the lethal and sublethal effects of different synthetic and botanical products on the broad mite Polyphagotarsonemus latus (Banks), a major pest of Capsicum annuum L. and other crops. Abamectin had the highest lethal effect on P. latus, followed by spiromesifen, azadirachtin, neem oil and nitrogen fertiliser + citric acid. The sublethal effects of the products were indicated by the influence on mite population growth, affecting the numbers of females, males, larvae, pupae and eggs. Furthermore, a negative instantaneous rate of increase in P. latus and repellent effects were observed. The lethal and sublethal effects of abamectin, spiromesifen, azadirachtin and neem oil significantly affect P. latus population growth, as well as causing repellence to this mite on C. annuum, and they should be considered in the integrated pest management of this mite. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  2. EVALUATION OF SUBLETHAL EFFECTS OF Ipomoea cairica LINN. EXTRACT ON LIFE HISTORY TRAITS OF DENGUE VECTORS

    Directory of Open Access Journals (Sweden)

    Wan Fatma ZUHARAH

    2016-01-01

    Full Text Available Plant derived insecticides have considerable potential for mosquito control because these products are safer than conventional insecticides. This study aimed to investigate sublethal activities of Ipomoea carica or railway creeper crude acethonilic extract against life history trait of dengue vectors, Aedes albopictus and Aedes aegypti. The late third instar larvae of Ae. albopictus and Ae. aegypti were exposed to a sublethal dose at LC50 and larvae that survived were further cultured. Overall, Ipomea cairica crude extracts affected the whole life history of both Aedes species. The study demonstrated significantly lower egg production (fecundity and eggs hatchability (fertility in Ae. albopictus. The sublethal dose of crude extracts reduced significantly the width of larval head capsule and the wing length of both sexes in both Aedes species. The significance of sublethal effects of I. cairica against Aedes mosquitoes was an additional hallmark to demonstrate further activity of this plant despite its direct toxicity to the larvae. The reduced reproductive capacity as well as morphological and physiological anomalies are some of the effects that make I. cairica a potential candidate to be used as a new plant-based insecticide to control dengue vectors.

  3. Monitoring colony-level effects of sublethal pesticide exposure on honey bees

    Science.gov (United States)

    The effects of sublethal pesticide exposure to honey bee colonies may be significant but difficult to detect in the field using standard visual assessment methods. Here we describe methods to measure the quantities of adult bees, brood and food resources by weighing hives and hive parts, by photogra...

  4. Impacts of chronic sublethal exposure to clothianidin on winter honeybees.

    Science.gov (United States)

    Alkassab, Abdulrahim T; Kirchner, Wolfgang H

    2016-07-01

    A wide application of systemic pesticides and detection of their residues in bee-collected pollen and nectar at sublethal concentrations led to the emergence of concerns about bees' chronic exposure and possible sublethal effects on insect pollinators. Therefore, special attention was given to reducing unintentional intoxications under field conditions. The sensitivity of winter bees throughout their long lifespan to residual exposure of pesticides is not well known, since most previous studies only looked at the effects on summer bees. Here, we performed various laboratory bioassays to assess the effects of clothianidin on the survival and behavior of winter bees. Oral lethal and sublethal doses were administered throughout 12-day. The obtained LD50 values at 48, 72, 96 h and 10 days were 26.9, 18.0, 15.1 and 9.5 ng/bee, respectively. Concentrations <20 µg/kg were found to be sublethal. Oral exposure to sublethal doses was carried out for 12-day and, the behavioral functions were tested on the respective 13th day. Although slight reductions in the responses at the concentrations 10 and 15 µg/kg were observed, all tested sublethal concentrations had showed non-significant effects on the sucrose responsiveness, habitation of the proboscis extension reflex and olfactory learning performance. Nevertheless, chronic exposure to 15 µg/kg affected the specificity of the early long-term memory (24 h). Since the tested concentrations were in the range of field-relevant concentrations, our results strongly suggest that related-effects on winter and summer bees' sensitivity should also be studied under realistic conditions.

  5. Sub-lethal effects of neonicitinoids on the alfalfa leafcutter bee, Megachile rotundata

    Science.gov (United States)

    Neonicotinoids are commonly used pesticides in U.S. agriculture. For many beneficial insect species, lethal effects of neonicotinoids are well-documented; however, much less is known about sublethal exposure. The alfalfa leaf cutter bee Megachile rotundata is a managed pollinator that constructs com...

  6. The suppressive effect of etoposide on recovery from sublethal radiation damage in Chinese hamster V 79 cells

    International Nuclear Information System (INIS)

    Saito, Tsutomu; Shimada, Yuji; Kawamori, Jiro; Kamata, Rikisaburo

    1992-01-01

    The combined effect of radiation and etoposide on the survival of cultured Chinese hamster V 79 cells was investigated. Cells in exponential growth phase were treated with various combinations of radiation and etoposide. The surviving fraction was assessed by colony formation. Etoposide significantly reduced so-called shoulder width, as expressed in Dq (quasithreshold dose), of radiation survival curves. The reduction depended on the increase of etoposide concentrations, although steepening of slopes of exponentially regressing portions of the radiation survival curves was slight. Split dose experiments showed that cells did not recover from sublethal radiation damage in the presence of low concentration of etoposide, although they did recover from sublethal radiation damage under a drug free condition. The results show the suppressive effect of etoposide on recovery from sublethal radiation damage. The effect of a sequential combination of radiation and etoposide was also investigated. The effect was more marked when the interval between radiation and etoposide was shorter regardless of the sequence. (author)

  7. Sublethal Effects of Insecticide Exposure on Megacopta cribraria (Fabricius) Nymphs: Key Biological Traits and Acetylcholinesterase Activity.

    Science.gov (United States)

    Miao, Jin; Reisig, Dominic D; Li, Guoping; Wu, Yuqing

    2016-01-01

    Megacopta cribraria F. (Hemiptera: Plataspidae), the kudzu bug, is an invasive insect pest of U.S. soybean. At present, insecticide application is the primary and most effective control option for M. cribraria In this study, the potential effects of sublethal and low-lethal concentrations (LC10 and LC40) of three common insecticides on key biological traits and acetylcholinesterase (AChE) activity of the treated nymphal stage of insect were assessed. The results show that the sublethal concentration of imidacloprid significantly reduced adult emergence rate of M. cribraria A low-lethal concentration of imidacloprid significantly increased nymphal development time, but significantly decreased adult emergence rate and adult longevity. Both sublethal and low-lethal concentrations of acephate caused an increase in nymphal development time and a reduction in adult emergence rate and adult longevity. Fecundity of females was significantly reduced only by exposure to low-lethal concentrations of acephate. Sublethal and low-lethal concentrations of bifenthrin increased nymphal development time, but significantly decreased adult emergence rate. In addition, we found that the AChE activity of M. cribraria was significantly increased only by LC40 imidacloprid, but strongly inhibited by acephate. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

  8. Effects of sublethal concentrations of formalin on weight gain in the ...

    African Journals Online (AJOL)

    The African Catfish, Clarias gariepinus, was exposed to various sublethal concentrations (25.0, 12.50, 6.25, 3.125, 1.56 and 0.0 mgl-1) of formalin to investigate their effects on the weight gain of the fish. Decrease in weight gain, directly proportional to the toxicant concentration, was observed in fish exposed to ...

  9. Effect of sublethal gamma radiation on host defenses in experimental scrub typhus

    International Nuclear Information System (INIS)

    Kelly, D.J.; Rees, J.C.

    1986-01-01

    The effect of sublethal gamma radiation on inbred mice chronically infected with scrub typhus rickettsiae was examined. Inbred mice which were inoculated with the Gilliam or Karp strain of Rickettsia tsutsugamushi by the subcutaneous route harbored the infection for at least 1 year. Irradiation of these animals at 12 or 52 weeks postinoculation with normally sublethal levels induced a significantly higher percentage of rickettsemic mice (recrudescence) than was seen in the unirradiated, similarly infected control animals. In addition, sublethal irradiation at 12 weeks induced a quantitative increase in total rickettsiae. Homologous antibody titers to the rickettsiae were examined for 5 weeks after irradiation to determine the role of the humoral response in radiation-induced recrudescence. Unirradiated, infected mice showed consistent titers of about 320 throughout the 5-week observation period, and the titer was not affected by exposure of up to 500 rads of gamma radiation. Drug dose-dependent radioprotection and modification of recrudescence was noted in infected, irradiated mice treated with the antiradiation compound S-2-(3-aminopropylamino)ethyl phosphorothioic acid. The results of this investigation supported the conclusion that the recrudescence of a chronic rickettsial infection in the appropriate host after immunological impairment due to gamma radiation can result in an acute, possibly lethal rickettsemia

  10. Assessment of chronic sublethal effects of imidacloprid on honey bee colony health

    Science.gov (United States)

    Here we present results of a three-year study to determine the fate of imidacloprid residues in hive matrices and to assess chronic sublethal effects on whole honey bee colonies fed supplemental pollen diet containing imidacloprid at 5, 20 and 100 µg/kg over multiple brood cycles. Various endpoints ...

  11. Erodibility of cemented materials

    CSIR Research Space (South Africa)

    Gass, BG

    1993-03-01

    Full Text Available The use of stabilised layers is cost effective in road construction in South Africa. Some stabilised materials have however been found to be susceptible to erosion. To identify erodible materials the Erosion Test was developed in 1989...

  12. The effect of thymus cells on bone marrow transplants into sublethally irradiated mice

    International Nuclear Information System (INIS)

    Kruszewski, J.A.; Szcylik, C.; Wiktor-Jedrzejczak, W.

    1984-01-01

    Bone marrow cells formed similar numbers of 10-days spleen colonies in sublethally (6 Gy) irradiated C57B1/6 mice as in lethally (7.5 Gy) irradiated mice i.e. approximately 20 per 10 5 cells. Numbers of 10 day endogenous spleen colonies in sublethally irradiated mice (0.2 to 0.6 per spleen) did not differ significantly from the numbers in lethally irradiated mice. Yet, transplants of 10 7 coisogenic marrow cells into sublethally irradiated mice resulted in predominantly endogenous recovery of granulocyte system as evidenced by utilization of ''beige'' marker for transplanted cells. Nevertheless, transplanted cells engrafted into sublethally irradiated mice were present in their hemopoietic tissues throughout the observation period of 2 months never exceeding 5 to 10% of cells. Thymus cells stimulated endogenous and exogenous spleen colony formation as well as endogenous granulopoietic recovery. Additionally, they increased both the frequency and absolute numbers of graft-derived granulocytic cells in hemopoietic organs of transplanted mice. They failed, however, to essentially change the quantitative relationships between endogenous and exogenous hemopoietic recovery. These results may suggest that spleen colony studies are not suitable for prediction of events following bone marrow transplant into sublethally irradiated mice. Simultaneously, they have strengthened the necessity for appropriate conditioning of recipients of marrow transplants. (orig.) [de

  13. Sub-lethal effects of Vip3A toxin on survival, development and fecundity of Heliothis virescens and Plutella xylostella.

    Science.gov (United States)

    Gulzar, Asim; Wright, Denis J

    2015-11-01

    The assessment of sub-lethal effects is important to interpret the overall insecticide efficacy in controlling insect pest populations. In addition to the lethal effect, sub-lethal effects may also occur in exposed insects. Vegetative insecticidal proteins (Vips) have shown a broad spectrum of insecticidal activity against many insect pest species. In this study the sub-lethal effects of the Bacillus thuringiensis vegetative insecticidal toxin Vip3A on the development and reproduction of Heliothis virescens F. and Plutella xylostella L. were evaluated in the laboratory. The results indicated that the sub-lethal concentration of Vip3A increased the duration of the larval and pupal stages as compared with the control treatment for both species. The percent pupation and percent adult emergence were significantly lower for Vip3A-treated insects. The proportion of pairs that produced eggs and the longevity of adults were not significantly different between treatments. H. virescens and P. xylostella treated with Vip3A showed an 11 and 17 % decrease in their intrinsic rate of increase (rm) respectively compared with untreated insects. The results from this study will be helpful to develop the strategy to incorporate Vip 3A containing crops in an integrated pest management programme.

  14. Soil erodibility for water erosion: A perspective and Chinese experiences

    Science.gov (United States)

    Wang, Bin; Zheng, Fenli; Römkens, Mathias J. M.; Darboux, Frédéric

    2013-04-01

    Knowledge of soil erodibility is an essential requirement for erosion prediction, conservation planning, and the assessment of sediment related environmental effects of watershed agricultural practices. This paper reviews the status of soil erodibility evaluations and determinations based on 80 years of upland area erosion research mainly in China and the USA. The review synthesizes the general research progress made by discussing the basic concepts of erodibility and its evaluation, determination, and prediction as well as knowledge of its spatio-temporal variations. The authors found that soil erodibility is often inappropriately or inaccurately applied in describing soil loss caused by different soil erosion component processes and mechanisms. Soil erodibility indicators were related to intrinsic soil properties and exogenic erosional forces, measurements, and calculations. The present review describes major needs including: (1) improved definition of erodibility, (2) modified erodibility determinations in erosion models, especially for specific geographical locations and in the context of different erosion sub-processes, (3) advanced methodologies for quantifying erodibilities of different soil erosion sub-processes, and (4) a better understanding of the mechanism that causes temporal variations in soil erodibility. The review also provides a more rational basis for future research on soil erodibility and supports predictive modeling of soil erosion processes and the development of improved conservation practices.

  15. Effect of set up time on sublethal repair in multifield fractionated radiotherapy

    International Nuclear Information System (INIS)

    Kehwar, T.S.; Beriwal, Sushil; Sharma, S.C.

    1998-01-01

    The sublethal repair between two doses given with a variable time interval for mammalian cells in tissue culture was first demonstrated successfully by Elkind and Sutton. Subsequently on the basis of concept of sublethal damage repair between fractions, the radio therapists and radio biologists realized that dose can be increased by increasing the small size fractions. This concept is successfully being used in modern radiotherapy

  16. Sublethal and hormesis effects of imidacloprid on the soybean aphid Aphis glycines.

    Science.gov (United States)

    Qu, Yanyan; Xiao, Da; Li, Jinyu; Chen, Zhou; Biondi, Antonio; Desneux, Nicolas; Gao, Xiwu; Song, Dunlun

    2015-04-01

    The soybean aphid, Aphis glycines Matsumura, is a major pest in soybean crop. Current management of this pest relies mainly on insecticides applications, and the neonicotinoid imidacloprid has been proposed as an effective insecticide to control A. glycines in soybean field. Imidacloprid at lethal concentrations not only exerts acute toxicity to A. glycines, but also cause various biological changes when aphids are chronically exposed to lower concentrations. In this study, we assessed the effects of a low-lethal (0.20 mg L(-1)) and two sublethal (0.05 and 0.10 mg L(-1)) imidacloprid concentrations on various A. glycines life history traits. Aphid exposure to 0.20 mg L(-1) imidacloprid caused slower juvenile development, shorter reproductive period, and reduced adult longevity, fecundity and total lifespan. Stimulatory effects, i.e. hormesis, on reproduction and immature development duration were observed in aphids exposed to the lower sublethal imidacloprid concentrations. Consequently, the net reproduction rate (R 0) was significantly higher than in the control aphids. These findings stress the importance of the actual imidacloprid concentration in its toxicological properties on A. glycines. Therefore, our results would be useful for assessing the overall effects of imidacloprid on A. glycines and for optimizing integrated pest management programs targeting this pest.

  17. Sublethal effects of carbaryl on embryonic and gonadal ...

    African Journals Online (AJOL)

    Carbaryl is a broad-spectrum insecticide used to control insect pests. In aquatic environments, it can disrupt the endocrine system and adversely affect the reproductive function of aquatic animals. This study investigated sublethal impacts of carbaryl on embryos and gonads of zebrafish Danio rerio in order to assess the ...

  18. Sublethal effect of imidacloprid on Solenopsis invicta (Hymenoptera: Formicidae) feeding, digging, and foraging behavior

    Science.gov (United States)

    There is increasing evidence that exposure to neonicotinoid insecticides at sublethal levels impairs colonies of honeybee and other pollinators. Recently, it was found that sublethal contamination with neonicotinoids also affect growth and behavior of ants. In this study, we exposed red imported fi...

  19. Effects Of Exposure To Sublethal Concentrations Of Azadirachta ...

    African Journals Online (AJOL)

    The physiological impairment on the fingerlings of Clarias gariepinus when exposed to sublethal concentrations of Azadirachta Indica was investigated. The fish were exposed to concentrations of 1.25, 2.50, 5.0, 10.0, 20.0 ML -1 for the period of 12 weeks. The crude protein content decreased with increased concentration ...

  20. Lethal and sublethal effects of four essential oils on the egg parasitoids Trissolcus basalis.

    Science.gov (United States)

    Werdin González, Jorge Omar; Laumann, Raúl Alberto; da Silveira, Samantha; Moraes, Maria Carolina Blassioli; Borges, Miguel; Ferrero, Adriana Alicia

    2013-07-01

    The essential oils from leaves of Schinus molle var. areira, Aloysia citriodora, Origanum vulgare and Thymus vulgaris have showed potential as phytoinsecticides against the green stink bug, Nezara viridula. In this work were evaluated their toxicological and behavioral effects on the parasitoid Trissolcus basalis, a biological control agent of this pest insect. Essential oils were obtained via hydrodestillation from fresh leaves. Insecticide activity in T. basalis females was evaluated in direct contact and fumigation bioassays. Behavioral effects were evaluated in olfactometer bioassays. To evaluate the residual toxicity, females of the parasitoids were exposed to oil residues; in these insects, the sublethal effects were evaluated (potential parasitism and survivorship of immature stages). The essential oils from O. vulgare and T. vulgaris proved to be highly selective when used as fumigant and did not change parasitoid behavior. After one week, the residues of these oils were harmless and did not show sublethal effects against T. basalis. According with these results, essential oils have potential applications for the integrated management of N. viridula. Published by Elsevier Ltd.

  1. Do Biopesticides Affect the Demographic Traits of a Parasitoid Wasp and Its Biocontrol Services through Sublethal Effects?

    Science.gov (United States)

    Biondi, Antonio; Zappalà, Lucia; Stark, John D.; Desneux, Nicolas

    2013-01-01

    Pesticide risk assessments are usually based on short-term acute toxicity tests, while longer-term population dynamic related traits, critical to the success of biological control and Integrated Pest Management (IPM) programs, are often overlooked. This is increasingly important with respect to new biopesticides that frequently cause no short-term acute effects, but that can induce multiple physiological and behavioral sublethal effects, leading to a decrease in population growth and ecosystem services. In this study we assessed the lethal and sublethal effects of six biopesticides [abamectin, azadirachtin, Bacillus thuringiensis, borax plus citrus oil (Prev-Am®), emamectin benzoate, and spinosad], used in tomato crops to control the invasive pest Tuta absoluta (Lepidoptera: Gelechiidae), on adults and pupae of the parasitoid Bracon nigricans (Hymenoptera: Braconidae). Data on female survival and production of female offspring were used to calculate population growth indexes as a measure of population recovery after pesticide exposure. Spinosad caused 100% and 80% mortality in exposed adults (even 10 d after the treatment) and pupae, respectively. Although most of the biopesticides had low levels of acute toxicity, multiple sublethal effects were observed. The biocontrol activity of both females that survived 1-h and 10-d old residues, and females that emerged from topically treated pupae was significantly affected by the application of the neurotoxic insecticides emamectin benzoate and abamectin. Furthermore, very low B. nigricans demographic growth indices were estimated for these two insecticides, indicating potential local extinction of the wasp populations. Among the tested products, Bt proved to be the safest for B. nigricans adults and pupae. Our findings emphasize that acute toxicity assessment alone cannot fully predict the actual impact of pesticides on non-target parasitoids. Thus, sublethal effects related to the species specific life-history variables

  2. Toxicokinetic-toxicodynamic modeling of quantal and graded sublethal endpoints: a brief discussion of concepts

    NARCIS (Netherlands)

    Ashauer, R.; Agatz, A.; Albert, C.; Ducrot, V.; Galic, N.G.; Hendriks, J.; Jager, T.; Kretschmann, A.; O'Connor, I.; Rubach, M.N.; Nyman, M.; Schmitt, W.; Stadnicka, J.; Brink, van den P.J.

    2011-01-01

    We report on the advantages and problems of using toxicokinetic-toxicodynamic (TKTD) models for the analysis, understanding, and simulation of sublethal effects. Only a few toxicodynamic approaches for sublethal effects are available. These differ in their effect mechanism and emphasis on linkages

  3. [Sublethal effects of spinetoram and azadirachtin on development and reproduction of Frankliniella occidentalis (Pergande).

    Science.gov (United States)

    Yang, Guang Ming; Zhi, Jun Rui; Li, Shun Xin; Liu, Li

    2016-11-18

    To evaluate the sublethal effects of spinetoram and azadirachtin on western flower thrips, Frankliniella occidentalis, leaf dipping method was used to determine their sublethal concentrations (LC 25 ) on the 2 nd instar nymph, and their influences on development and reproduction of F. occidentalis were studied. The results showed exposure of sublethal concentrations of spinetoram and azadirachtin to F. accidentalis had different degrees of effects on this insect pest. Under bisexual reproduction, the LC 25 spinetoram had no significant influences on pre-oviposition period, female adult longevity and fecundity, but male adult longevity was significantly shorter than the control. The LC 25 azadirachtin significantly reduced fecundity and prolonged pre-oviposition period. Under parthenogenesis, the LC 25 spinetoram and azadirachtin extended the pre-oviposition duration, whereas the LC 25 azadirachtin shortened the female adult longevity and significantly decreased fecundity. The LC 25 spinetoram and azadirachtin had different influences on developmental duration of each stage of next generation. The immature stage in treatment group of the LC 25 spinetoram was shorter than that in treatment group of the LC 25 azadirachtin, under bisexual reproduction or parthenogenesis. Intrinsic rate of increase (r m ) and finite rate of increase (λ) of population treated by the LC 25 spinetoram were higher than those of the control, whereas the r m , R 0 , and λ of population treated by the LC 25 azadirachtin were lower than those of the control. The findings indicated that the effects of the LC 25 spinetoram and azadirachtin on the development and reproduction of F. accidentalis were different. The LC 25 spinetoram had certain stimulating effect, whereas the LC 25 azadirach-tinon had significant inhibitory effect. Two biopesticides' influences were related with the reproductive patterns of F. accidentalis.

  4. Protective effect of milk constituents and sublethal injuries limiting process effectiveness during PEF inactivation of Lb. rhamnosus.

    Science.gov (United States)

    Jaeger, H; Schulz, A; Karapetkov, N; Knorr, D

    2009-08-31

    The inactivation of Lb. rhamnosus by pulsed electric field treatment (PEF) was studied in different fractions of raw milk and Ringer solution in order to evaluate the protective effect of nutrient rich media in comparison to aqueous buffer solutions. Apart from monitoring of culturability, analysis of the physiological fitness of Lb. rhamnosus was conducted aiming to identify sublethally damaged cells. Therefore, flow cytometry and a selective medium plating technique were used and compared to each other. The goal of the study was to apply three different parameters describing the physiological fitness of the model organism Lb. rhamnosus after PEF treatment such as culturability, membrane permeability and metabolic activity depending on treatment media and parameters. A concentration dependent protective effect of the milk protein fraction could be shown and allocated to micellar casein as the major milk protein. Increasing the concentration of whey proteins up to 2% showed a similar impact on limiting the PEF inactivation of Lb. rhamnosus. The evaluation of physiological fitness of cells was based on a determination of structural and functional characteristics by rapid cellular staining using carboxyfluorescein diacetate and propidium iodide. This approach showed good accordance to the conventional selective medium plating technique for the enumeration of sublethally-injured bacteria but flow cytometry provided additional information for the characterisation of this fraction. The extent of occurrence of dead, sublethal and vital fractions of cells was found dependent on the PEF treatment parameters such as electrical field strength and energy input as well as the different milk fractions used as treatment media.

  5. Toxicokinetic-toxicodynamic modelling of quantal and graded sub-lethal endpoints - a brief discussion of concepts.

    NARCIS (Netherlands)

    Ashauer, R.; Agatz, A.; Albert, C.; Ducrot, V.; Galic, N.; Hendriks, A.J.; Jager, T.; Kretschmann, A.; O'Connor, I.; Rubach, M.N.; Nyman, A.M.; Schmitt, W.; Stadnicka, J.; van den Brink, P.; Preuss, T.G.

    2011-01-01

    We report on the advantages and problems of using toxicokinetic-toxicodynamic (TKTD) models for the analysis, understanding, and simulation of sublethal effects. Only a few toxicodynamic approaches for sublethal effects are available. These differ in their effect mechanism and emphasis on linkages

  6. Effect of CPP-ACP on the remineralization of acid-eroded human tooth enamel: nanomechanical properties and microtribological behaviour study

    International Nuclear Information System (INIS)

    Zheng, L; Zheng, J; Zhang, Y F; Qian, L M; Zhou, Z R

    2013-01-01

    Casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP) has been used to enhance tooth remineralization in the dental clinic. But the contribution of CPP-ACP to the remineralization of acid-eroded human tooth enamel is of widespread controversy. To confirm the application potential of CPP-ACP in the remineralization repair of tooth erosion caused by acid-attack, the effect of remineralization in vitro in 2% w/v CPP-ACP solution on the acid-eroded human tooth enamel was investigated in this study. The repair of surface morphology and the improvement of nanomechanical and microtribological properties were characterized with laser confocal scanning microscope, scanning electron microscope, nanoindentation tester and nanoscratch tester. Results showed that a layer of uneven mineral deposits, which were mainly amorphous calcium phosphate (ACP) in all probability, was observed on the acid-eroded enamel surface after remineralization. Compared with the acid-eroded enamel surface, the nanoindentation hardness and Young's modulus of the remineralized enamel surface obviously increased. Both the friction coefficient and wear volume of the acid-eroded enamel surface decreased after remineralization. However, both the nanomechanical and the anti-wear properties of the remineralized enamel surface were still inferior to those of original enamel surface. In summary, tooth damage caused by acid erosion could be repaired by remineralization in CPP-ACP solution, but the repair effect, especially on the nanomechanical and anti-wear properties of the acid-eroded enamel, was limited. These results would contribute to a further exploration of the remineralization potential of CPP-ACP and a better understanding of the remineralization repair mechanism for acid-eroded human tooth enamel. (paper)

  7. Effect of CPP-ACP on the remineralization of acid-eroded human tooth enamel: nanomechanical properties and microtribological behaviour study

    Science.gov (United States)

    Zheng, L.; Zheng, J.; Zhang, Y. F.; Qian, L. M.; Zhou, Z. R.

    2013-10-01

    Casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP) has been used to enhance tooth remineralization in the dental clinic. But the contribution of CPP-ACP to the remineralization of acid-eroded human tooth enamel is of widespread controversy. To confirm the application potential of CPP-ACP in the remineralization repair of tooth erosion caused by acid-attack, the effect of remineralization in vitro in 2% w/v CPP-ACP solution on the acid-eroded human tooth enamel was investigated in this study. The repair of surface morphology and the improvement of nanomechanical and microtribological properties were characterized with laser confocal scanning microscope, scanning electron microscope, nanoindentation tester and nanoscratch tester. Results showed that a layer of uneven mineral deposits, which were mainly amorphous calcium phosphate (ACP) in all probability, was observed on the acid-eroded enamel surface after remineralization. Compared with the acid-eroded enamel surface, the nanoindentation hardness and Young's modulus of the remineralized enamel surface obviously increased. Both the friction coefficient and wear volume of the acid-eroded enamel surface decreased after remineralization. However, both the nanomechanical and the anti-wear properties of the remineralized enamel surface were still inferior to those of original enamel surface. In summary, tooth damage caused by acid erosion could be repaired by remineralization in CPP-ACP solution, but the repair effect, especially on the nanomechanical and anti-wear properties of the acid-eroded enamel, was limited. These results would contribute to a further exploration of the remineralization potential of CPP-ACP and a better understanding of the remineralization repair mechanism for acid-eroded human tooth enamel.

  8. Soil erodibility variability in laboratory and field rainfall simulations

    Science.gov (United States)

    Szabó, Boglárka; Szabó, Judit; Jakab, Gergely; Centeri, Csaba; Szalai, Zoltán

    2017-04-01

    Rainfall simulation experiments are the most common way to observe and to model the soil erosion processes in in situ and ex situ circumstances. During modelling soil erosion, one of the most important factors are the annual soil loss and the soil erodibility which represent the effect of soil properties on soil loss and the soil resistance against water erosion. The amount of runoff and soil loss can differ in case of the same soil type, while it's characteristics determine the soil erodibility factor. This leads to uncertainties regarding soil erodibility. Soil loss and soil erodibility were examined with the investigation of the same soil under laboratory and field conditions with rainfall simulators. The comparative measurement was carried out in a laboratory on 0,5 m2, and in the field (Shower Power-02) on 6 m2 plot size where the applied slope angles were 5% and 12% with 30 and 90 mm/h rainfall intensity. The main idea was to examine and compare the soil erodibility and its variability coming from the same soil, but different rainfall simulator type. The applied model was the USLE, nomograph and other equations which concern single rainfall events. The given results show differences between the field and laboratory experiments and between the different calculations. Concerning for the whole rainfall events runoff and soil loss, were significantly higher at the laboratory experiments, which affected the soil erodibility values too. The given differences can originate from the plot size. The main research questions are that: How should we handle the soil erodibility factors and its significant variability? What is the best solution for soil erodibility determination?

  9. Effects of sublethal exposure to metofluthrin on the fitness of Aedes aegypti in a domestic setting in Cairns, Queensland

    OpenAIRE

    Buhagiar, Tamara S.; Devine, Gregor J.; Ritchie, Scott A.

    2017-01-01

    Background Metofluthrin is highly effective at reducing biting activity in Aedes aegypti. Its efficacy lies in the rapid onset of confusion, knockdown, and subsequent kill of a mosquito. In the field, there are a variety of scenarios that might result in sublethal exposure to metofluthrin, including mosquitoes that are active at the margins of the chemical?s lethal range, brief exposure as mosquitoes fly in and out of treated spaces or decreasing efficacy of the emanators with time. Sublethal...

  10. Effects of Sublethal Concentrations of Cyantraniliprole on the Development, Fecundity and Nutritional Physiology of the Black Cutworm Agrotis ipsilon (Lepidoptera: Noctuidae.

    Directory of Open Access Journals (Sweden)

    Chunmei Xu

    Full Text Available To better understand the sublethal effects of cyantraniliprole on the black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae, several studies were carried out to investigate sublethal effects on development stages, population parameters, feeding indices and nutrient content of A. ipsilon. The result of a bioassay showed that cyantraniliprole had high toxicity against A. ipsilon fourth-instar larvae with an LC50 of 0.354 μg.g-1 using an artificial diet. Compared with controls, sublethal doses of cyantraniliprole at LC5, LC20 and LC40 levels prolonged larval and pupal duration and extended mean generation time and total preovipositional period. In addition, survival rate, reproductive value, intrinsic and finite rates of increase and net reproduction rate declined significantly. Meanwhile, cyantraniliprole had markedly antifeedant effects; decreased the relative growth rate (RGR, the relative consumption rate (RCR, the efficiency of conversion of ingested food (ECI, the efficiency of conversion of digested food (ECD; and increased the approximate digestibility (AD significantly. This phenomenon contributed to the decrease of nutrient contents, including lipids, protein and carbohydrates, to the point that insufficient energy was available for normal growth. Therefore, sublethal concentrations of cyantraniliprole decreased growth speed and reduced population reproduction of A. ipsilon. This result provides information useful in integrated pest management (IPM programs for A. ipsilon.

  11. Effect of sublethal preculturing on the survival of probiotics and metabolite formation in set-yoghurt

    NARCIS (Netherlands)

    Settachaimongkon, S.; Valenberg, van H.J.F.; Winata, V.; Wang, X.; Nout, M.J.R.; Hooijdonk, van A.C.M.; Zwietering, M.H.; Smid, E.J.

    2015-01-01

    The objective of this study was to investigate the effect of preculturing of Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis BB12 under sublethal stress conditions on their survival and metabolite formation in set-yoghurt. Prior to co-cultivation with yoghurt starters in milk,

  12. Do biopesticides affect the demographic traits of a parasitoid wasp and its biocontrol services through sublethal effects?

    Directory of Open Access Journals (Sweden)

    Antonio Biondi

    Full Text Available Pesticide risk assessments are usually based on short-term acute toxicity tests, while longer-term population dynamic related traits, critical to the success of biological control and Integrated Pest Management (IPM programs, are often overlooked. This is increasingly important with respect to new biopesticides that frequently cause no short-term acute effects, but that can induce multiple physiological and behavioral sublethal effects, leading to a decrease in population growth and ecosystem services. In this study we assessed the lethal and sublethal effects of six biopesticides [abamectin, azadirachtin, Bacillus thuringiensis, borax plus citrus oil (Prev-Am®, emamectin benzoate, and spinosad], used in tomato crops to control the invasive pest Tuta absoluta (Lepidoptera: Gelechiidae, on adults and pupae of the parasitoid Bracon nigricans (Hymenoptera: Braconidae. Data on female survival and production of female offspring were used to calculate population growth indexes as a measure of population recovery after pesticide exposure. Spinosad caused 100% and 80% mortality in exposed adults (even 10 d after the treatment and pupae, respectively. Although most of the biopesticides had low levels of acute toxicity, multiple sublethal effects were observed. The biocontrol activity of both females that survived 1-h and 10-d old residues, and females that emerged from topically treated pupae was significantly affected by the application of the neurotoxic insecticides emamectin benzoate and abamectin. Furthermore, very low B. nigricans demographic growth indices were estimated for these two insecticides, indicating potential local extinction of the wasp populations. Among the tested products, Bt proved to be the safest for B. nigricans adults and pupae. Our findings emphasize that acute toxicity assessment alone cannot fully predict the actual impact of pesticides on non-target parasitoids. Thus, sublethal effects related to the species specific life

  13. The effects of oil sands wastewater on fish resulting from exposure to sub-lethal concentrations

    International Nuclear Information System (INIS)

    Birkholz, D.A.; Goudey, J.S.; Balch, G.C.; Nelson, L.R.; MacKinnon, M.

    1995-01-01

    Rainbow trout, Oncorhynchus mykiss, were exposed to sub-lethal concentrations of oil sands wastewater in flow through laboratory experiments as well as to artificial ponds containing sub-lethal concentrations of tailings pond water and fine tails in order to study the viability of the wet landscape remediation option. Large (200--300 g) fish were used for all the exposures in this preliminary study and the following data were collected: blood cell counts, sex hormone concentrations, sexual maturation, stress protein concentrations, PAH-metabolites in bile, condition factors, liver somatic indices, mixed function oxygenase induction, PAHs in muscle, external condition and the condition of internal organs. The data obtained from this study revealed no adverse effects upon fish during extended field exposures. Given similar exposure conditions in the release waters of a wet landscape reclamation, the data suggest that there may be no adverse effects upon fish, however, longer term studies, other indicator organisms and additional chronic tests should be conducted

  14. Lethal and Sub-lethal Effects of Four Insecticides on the Aphidophagous Coccinellid Adalia bipunctata (Coleoptera: Coccinellidae).

    Science.gov (United States)

    Depalo, Laura; Lanzoni, Alberto; Masetti, Antonio; Pasqualini, Edison; Burgio, Giovanni

    2017-12-05

    Conventional insecticide assays, which measure the effects of insecticide exposure on short-term mortality, overlook important traits, including persistence of toxicity or sub-lethal effects. Therefore, such approaches are especially inadequate for prediction of the overall impact of insecticides on beneficial arthropods. In this study, the side effects of four modern insecticides (chlorantraniliprole, emamectin benzoate, spinosad, and spirotetramat) on Adalia bipunctata (L.) (Coleoptera: Coccinellidae) were evaluated under laboratory conditions by exposition on treated potted plants. In addition to investigation of acute toxicity and persistence of harmful activity in both larvae and adults of A. bipunctata, demographic parameters were evaluated, to provide a comprehensive picture of the nontarget effects of these products. Field doses of the four insecticides caused detrimental effects to A. bipunctata; but in different ways. Overall, spinosad showed the best toxicological profile among the products tested. Emamectin benzoate could be considered a low-risk insecticide, but had high persistence. Chlorantraniliprole exhibited lethal effects on early instar larvae and adults, along with a long-lasting activity, instead spirotetramat showed a low impact on larval and adult mortality and can be considered a short-lived insecticide. However, demographic analysis demonstrated that chlorantraniliprole and spirotetramat caused sub-lethal effects. Our findings highlight that sole assessment of mortality can lead to underestimation of the full impact of pesticides on nontarget insects. Demographic analysis was demonstrated to be a sensitive method for detection of the sub-lethal effects of insecticides on A. bipunctata, and this approach should be considered for evaluation of insecticide selectivity. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Testing the effect of a microbial-based soil amendment on aggregate stability and erodibility

    DEFF Research Database (Denmark)

    Malozo, Mponda; Iversen, Bo Vangsø; Heckrath, Goswin Johann

    to the rainfall-runoff experiment where the microbial-based product had a clear effect on soil erodibility. In relation to measurement of aggregate stability as well as clay dispersion, the picture was less clear. Especially for the sandy Tanzania soil with a low content of organic matter, a clear effect was seen...... aggregate stability and erodibility. Two commercial products, gypsum and a microbial-based solution were used for the experiment and were tested on two Danish sandy loamy soils as well on a sandy soil from Tanzania. The carrier of the microbial-based product, a glycerol solution, was tested as well....... In the laboratory, soils were treated with the soil amendments in a two-step procedure at controlled water contents following aerobic incubation in closed containers. Water-aggregate stability and clay dispersion were measured on soil aggregates less than 8 mm in diameter. Aggregate stability was measured...

  16. Sublethal effect of neem extract on mediterranean fruit fly adults

    Directory of Open Access Journals (Sweden)

    Márcio Alves Silva

    2013-03-01

    Full Text Available The sublethal effect of extracts of Azadirachta indica on Ceratitis capitata was evaluated. Two pairs of flies were treated in plastic tubes with cotton placed in plastic cages. An artificial diet (hydrolyzed protein + sugar was provided ad libitum. The extracts affected significantly the longevity of C. capitata. The pre-oviposition period were not significantly affected by the extracts. The A. indica branches extracted with dichloromethane (888 ppm affected significantly the fecundity and fertility, reducing the number of eggs laid to approximately 80 % and the egg hatching by 30 % at the 8th day. Therefore, the neem branches extracted with dichloromethane affected the reproduction of C. capitata.

  17. Sublethal effects of imidacloprid on targeting muscle and ribosomal protein related genes in the honey bee Apis mellifera L.

    Science.gov (United States)

    Wu, Yan-Yan; Luo, Qi-Hua; Hou, Chun-Sheng; Wang, Qiang; Dai, Ping-Li; Gao, Jing; Liu, Yong-Jun; Diao, Qing-Yun

    2017-11-21

    A sublethal concentration of imidacloprid can cause chronic toxicity in bees and can impact the behavior of honey bees. The nectar- and water-collecting, and climbing abilities of bees are crucial to the survival of the bees and the execution of responsibilities in bee colonies. Besides behavioral impact, data on the molecular mechanisms underlying the toxicity of imidacloprid, especially by the way of RNA-seq at the transcriptomic level, are limited. We treated Apis mellifera L. with sublethal concentrations of imidacloprid (0.1, 1 and 10 ppb) and determined the effect on behaviors and the transcriptomic changes. The sublethal concentrations of imidacloprid had a limited impact on the survival and syrup consumption of bees, but caused a significant increase in water consumption. Moreover, the climbing ability was significantly impaired by 10 ppb imidacloprid at 8 d. In the RNA-seq analysis, gene ontology (GO) term enrichment indicated a significant down-regulation of muscle-related genes, which might contribute to the impairment in climbing ability of bees. The enriched GO terms were attributed to the up-regulated ribosomal protein genes. Considering the ribosomal and extra-ribosomal functions of the ribosomal proteins, we hypothesized that imidacloprid also causes cell dysfunction. Our findings further enhance the understanding of imidacloprid sublethal toxicity.

  18. Acute toxicities and sublethal effects of some conventional insecticides on Trichogramma chilonis (Hymenoptera: Trichogrammatidae).

    Science.gov (United States)

    Wang, De-Sen; He, Yu-Rong; Guo, Xiang-Ling; Luo, Yong-Li

    2012-08-01

    The acute toxicity of 10 conventional insecticides to adult of Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) was bioassayed by membrane method, and then their sublethal effects on the parasitoid were evaluated in the laboratory. Based on sublethal concentration (LC30) values at 8 h after treatment, we determined that adult T. chilonis were the most susceptible to chlorfenapyr, followed by fipronil, spinosad, avermectins, beta-cypermethrin, and cartap, with lethal concentration (LC)30 values of 0.3133, 0.3269, 1.5408, 3.2961, 6.1469, and 9.021 mg/liter, respectively. The field-recommended concentrations of chlorfluazuron, indoxacarb, Bacillus thuringiensis, and tebufenozide caused Cartap and spinosad also reduced longevity (8 and 7.9 d) and fecundity (110.77 and 117.2) of treated adults, but cartap enhanced the female percentage of F1 offspring (61.6%), resulting a statistical higher R0, r(m), and lambda of treated T. chilonis. In contrast, chlorfluazuron and tebufenozide increased longevity (16.4 and 15.4 d) and fecundity (248 and 256.9) of treated adults but slightly decreased the female percentage of F1 offspring (31.4 and 38.1%). Although chlorfenapyr showed no adverse influence on longevity and fecundity, it remarkably reduced the female percentage of F1 offspring (13.5%), leading to a lower R0, r(m), and lambda of treated T. chilonis. Indoxacarb, B. thuringiensis, and beta-cypermethrin had no obvious sublethal effects on the longevity and fecundity of treated adults. Based on these results, we consider B. thuringienesis, chlorfluazuron, indoxacarb, beta-cypermethrin, and tebufenozide safe to T. chilonis, suggesting that these insecticides are compatible with this parasitoid when being used in the field. However, fipronil, chlorfenapyr, spinosad, and avermectins were very harmful to T. chilonis. Timing of application of these insecticides was critical.

  19. Survival rate of honeybee (Apis mellifera) workers after exposure to sublethal concentrations of imidacloprid

    NARCIS (Netherlands)

    Blacquiere, T.

    2010-01-01

    Imidacloprid is a commonly used systemic insecticide which can induce several sublethal effects. Previous research has not shown any increased mortality in bees that were fed with sublethal doses. However, there is very little research conducted with the focus on survival rate of honeybees in the

  20. Sublethal effects of buprofezin on development and reproduction in the white-backed planthopper, Sogatella furcifera (Hemiptera: Delphacidae).

    Science.gov (United States)

    Ali, Ehsan; Liao, Xun; Yang, Peng; Mao, Kaikai; Zhang, Xiaolei; Shakeel, Muhammad; Salim, Abdalla M A; Wan, Hu; Li, Jianhong

    2017-12-05

    In the present study, the effects of sublethal concentrations of buprofezin on life-table traits of S. furcifera were evaluated for two consecutive generations (F0 and F1). Our results exhibited that the fecundity, life span (longevity) and hatchability of the F0 and F1 generations were significantly decreased at LC 30 compared to the control. However, copulation was not significantly affected for the F0 or F1 generations at sublethal concentrations. The female life span was affected negatively at both treatments in F0 and at LC 30 in F1, compared to the control. Furthermore, significant effects of the sublethal concentrations were found on the developmental rate of all instars except the 3 rd instar of F1. However, the pre-adult period, total pre-oviposition period (TPOP) and adult pre-oviposition period (APOP) significantly increased in F1 individuals at LC 30 and LC 10 compared to the control. Our findings revealed that demographic characters (survival rate, intrinsic rate of increase (ri), finite rate of increase (λ), net reproductive rate (R 0 ), and gross reproductive rate (GRR)) of the F1 generation (from F0 parents) significantly decreased compared to the untreated group; however, the generation time (T) increased at LC 10 . Therefore, the results suggested that buprofezin could adversely affect individuals in the successive generation.

  1. Soil erodibility in Europe: a high-resolution dataset based on LUCAS.

    Science.gov (United States)

    Panagos, Panos; Meusburger, Katrin; Ballabio, Cristiano; Borrelli, Pasqualle; Alewell, Christine

    2014-05-01

    The greatest obstacle to soil erosion modelling at larger spatial scales is the lack of data on soil characteristics. One key parameter for modelling soil erosion is the soil erodibility, expressed as the K-factor in the widely used soil erosion model, the Universal Soil Loss Equation (USLE) and its revised version (RUSLE). The K-factor, which expresses the susceptibility of a soil to erode, is related to soil properties such as organic matter content, soil texture, soil structure and permeability. With the Land Use/Cover Area frame Survey (LUCAS) soil survey in 2009 a pan-European soil dataset is available for the first time, consisting of around 20,000 points across 25 Member States of the European Union. The aim of this study is the generation of a harmonised high-resolution soil erodibility map (with a grid cell size of 500 m) for the 25 EU Member States. Soil erodibility was calculated for the LUCAS survey points using the nomograph of Wischmeier and Smith (1978). A Cubist regression model was applied to correlate spatial data such as latitude, longitude, remotely sensed and terrain features in order to develop a high-resolution soil erodibility map. The mean K-factor for Europe was estimated at 0.032 thahha(-1)MJ(-1)mm(-1) with a standard deviation of 0.009 thahha(-1)MJ(-1)mm(-1). The yielded soil erodibility dataset compared well with the published local and regional soil erodibility data. However, the incorporation of the protective effect of surface stone cover, which is usually not considered for the soil erodibility calculations, resulted in an average 15% decrease of the K-factor. The exclusion of this effect in K-factor calculations is likely to result in an overestimation of soil erosion, particularly for the Mediterranean countries, where highest percentages of surface stone cover were observed. Copyright © 2014. Published by Elsevier B.V.

  2. Lethal and sublethal cellular injury in multifraction irradiation

    International Nuclear Information System (INIS)

    Withers, H.R.

    1975-01-01

    Work has been carried out on cellular injury in multifraction irradiation of mouse tissues and compared with similar work on human skin reported earlier by Dutreix et al (Eur. J. Cancer.; 9:159 (1973)). In agreement with Dutreix et al it is emphasized that the absolute amount of sublethal injury repaired per fractionation interval (Dsub(r)) is not as important to radiotherapists as the change in the amount repaired (ΔDsub(r)) when the dose-per-fraction is altered. It was found that although there is a critical divergence at low doses, the data for mouse tissues are similar to those previously given for human skin and support the conclusions: (i) That the capacity of many normal cells for accumulating and repairing sublethal radiation injury is probably not greatly different. (ii) That fixed exponents used for fraction number and time in iso-effect formulae are inaproporiate. At low doses-per-fraction, repair of sublethal injury is complete, or nearly so, and hence, additional fractionation of dose does not give appreciable additional sparing, whereas rapidly-regenerating tissues, due to the lengthening of overall time, would continue being spared by repopulation. (U.K.)

  3. Effect of lethal and sub-lethal concentrations of tobacco (Nicotiana ...

    African Journals Online (AJOL)

    Lethal and sub-lethal bioassays on Clarias gariepinus were conducted to evaluate the toxicity of tobacco (Nicotiana tobaccum) leaf dust on weight gain and haematological indices of Clarias gariepinus (mean weight 10.5±0.70g) in glass aquaria with aeration system. The concentrations used during the lethal exposure are: ...

  4. Sublethal irradiation promotes invasiveness of neuroblastoma cells

    International Nuclear Information System (INIS)

    Schweigerer, Lothar; Rave-Fraenk, Margret; Schmidberger, Heinz; Hecht, Monica

    2005-01-01

    Neuroblastoma is the most frequent extracranial solid tumour of childhood. Despite multiple clinical efforts, clinical outcome has remained poor. Neuroblastoma is considered to be radiosensitive, but some clinical studies including the German trial NB90 failed to show a clinical benefit of radiation therapy. The mechanisms underlying this apparent discrepancy are still unclear. We have therefore investigated the effects of radiation on neuroblastoma cell behaviour in vitro. We show that sublethal doses of irradiation up-regulated the expression of the hepatocyte growth factor (HGF) and its receptor c-Met in some neuroblastoma cell lines. The increase in HGF/c-Met expression was correlated with enhanced invasiveness and activation of proteases degrading the extracellular matrix. Thus, irradiation at sublethal doses may promote the metastatic dissemination of neuroblastoma cells through activating the HGF/c-Met pathway and triggering matrix degradation

  5. Histological examination of sublethal effects of diazinon on ovary of bluegill, Lepomis macrochirus

    International Nuclear Information System (INIS)

    Dutta, H.M.; Maxwell, L.B.

    2003-01-01

    Sublethal doses of diazinon can alter microscopic anatomy of fish ovary. - The effects of the insecticide, diazinon (an organophosphorous compound), on the ovaries of bluegill (Lepomis macrohirus) were studied. Histological preparations of bluegill ovarian tissue was examined at 24, 48, 72 and 96 h and 1, 2 and 3 weeks following exposure to sublethal doses of diazinon (60 μg/l). The control contained primary follicles with an intact ovigerous lamellae and tunica albuginea. The control also revealed well developed stage IV oocytes with properly distributed provitelline nucleoli. After 24 h of exposure to diazinon, primary follicles began to show adhesion and cytoplasmic retraction in oocyte II occured. Cytoplasmic degeneration and additional adhesion and more retraction were visible at 48 h in oocyte II; 72 h brought forth adhesion, retraction and cytoplamic expulsion from oocyte IV. The number of atretic oocytes increased. Damages to the oocyte IV started to occur after 72 h of exposure. Cytoplasmic retraction and clumping was more visible at 96 h in oocyte IV. Partial destruction of the ovigerous lamellae and vitellogenic membrane occurred after 1 week. Two weeks continued to reveal destruction of follicles. Severe damage of the ovigerous lamellae, increased intrafollicular spaces, vacuolated cytoplasm, extrusion of karyoplasm and necrosis in the cytoplasm were most evident following 3 weeks of exposure. The ovarian wall became frayed and broken. Additionally, a marked increase of atretic follicles, shrinkage, and embedded nucleoli into the surrounding cytoplasm in oocyte II, III and IV were observed at week 3. This study revealed that oocytes at their different stages of maturation get affected differently at various exposure. Based on observations of the ovarian tissue compositional and structural changes following given exposure times, it becomes evident that consistent sublethal doses of diazinon can and will alter microscopic anatomy of the fish ovary

  6. Histological examination of sublethal effects of diazinon on ovary of bluegill, Lepomis macrochirus

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, H.M.; Maxwell, L.B

    2003-01-01

    Sublethal doses of diazinon can alter microscopic anatomy of fish ovary. - The effects of the insecticide, diazinon (an organophosphorous compound), on the ovaries of bluegill (Lepomis macrohirus) were studied. Histological preparations of bluegill ovarian tissue was examined at 24, 48, 72 and 96 h and 1, 2 and 3 weeks following exposure to sublethal doses of diazinon (60 {mu}g/l). The control contained primary follicles with an intact ovigerous lamellae and tunica albuginea. The control also revealed well developed stage IV oocytes with properly distributed provitelline nucleoli. After 24 h of exposure to diazinon, primary follicles began to show adhesion and cytoplasmic retraction in oocyte II occured. Cytoplasmic degeneration and additional adhesion and more retraction were visible at 48 h in oocyte II; 72 h brought forth adhesion, retraction and cytoplamic expulsion from oocyte IV. The number of atretic oocytes increased. Damages to the oocyte IV started to occur after 72 h of exposure. Cytoplasmic retraction and clumping was more visible at 96 h in oocyte IV. Partial destruction of the ovigerous lamellae and vitellogenic membrane occurred after 1 week. Two weeks continued to reveal destruction of follicles. Severe damage of the ovigerous lamellae, increased intrafollicular spaces, vacuolated cytoplasm, extrusion of karyoplasm and necrosis in the cytoplasm were most evident following 3 weeks of exposure. The ovarian wall became frayed and broken. Additionally, a marked increase of atretic follicles, shrinkage, and embedded nucleoli into the surrounding cytoplasm in oocyte II, III and IV were observed at week 3. This study revealed that oocytes at their different stages of maturation get affected differently at various exposure. Based on observations of the ovarian tissue compositional and structural changes following given exposure times, it becomes evident that consistent sublethal doses of diazinon can and will alter microscopic anatomy of the fish ovary.

  7. Synergistic Effect of Combining Plutella xylostella Granulovirus and Bacillus thuringiensis at Sublethal Dosages on Controlling of Diamondback Moth (Lepidoptera: Plutellidae).

    Science.gov (United States)

    Han, Guangjie; Li, Chuanming; Liu, Qin; Xu, Jian

    2015-10-01

    Plutella xylostella granulovirus (PxGV) and Bacillus thuringiensis (Bt) are both entomo-pathogens to the diamondback moth, Plutella xylostella (L.). The purpose of the present study was to measure the effect of the combination of PxGV and Bt at sublethal dosages on the development and mortality of diamondback moth in a laboratory setting. Bt and PxGV exhibited synergistic effect on diamondback moth larval mortality and effectively controlled diamondback moth populations with low dose combination treatment. The combination of three parts per million Bt and 1.3 × 10(3) occlusion bodies per milliliter of PxGV revealed a higher larval mortality compared with the treatment of Bt or PxGV alone. Combination of Bt and PxGV at sublethal concentrations also increased larval duration, reduced oviposition and decreased adult longevity remarkably, resulting in the lowest population trend index among the treatments. The results suggested that the combination of Bt and PxGV at sublethal dosages might provide a valuable way to improve the control efficacy of diamondback moth compared with treatment of Bt or PxGV alone. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Toxicity, sublethal effects, and potential modes of action of select fungicides on freshwater fish and invertebrates

    Science.gov (United States)

    Elskus, Adria A.

    2012-01-01

    Despite decades of agricultural and urban use of fungicides and widespread detection of these pesticides in surface waters, relatively few data are available on the effects of fungicides on fish and invertebrates in the aquatic environment. Nine fungicides are reviewed in this report: azoxystrobin, boscalid, chlorothalonil, fludioxonil, myclobutanil, fenarimol, pyraclostrobin, pyrimethanil, and zoxamide. These fungicides were identified as emerging chemicals of concern because of their high or increasing global use rates, detection frequency in surface waters, or likely persistence in the environment. A review of the literature revealed significant sublethal effects of fungicides on fish, aquatic invertebrates, and ecosystems, including zooplankton and fish reproduction, fish immune function, zooplankton community composition, metabolic enzymes, and ecosystem processes, such as leaf decomposition in streams, among other biological effects. Some of these effects can occur at fungicide concentrations well below single-species acute lethality values (48- or 96-hour concentration that effects a response in 50 percent of the organisms, that is, effective concentration killing 50 percent of the organisms in 48 or 96 hours) and chronic sublethal values (for example, 21-day no observed adverse effects concentration), indicating that single-species toxicity values may dramatically underestimate the toxic potency of some fungicides. Fungicide modes of toxic action in fungi can sometimes reflect the biochemical and (or) physiological effects of fungicides observed in vertebrates and invertebrates; however, far more studies are needed to explore the potential to predict effects in nontarget organisms based on specific fungicide modes of toxic action. Fungicides can also have additive and (or) synergistic effects when used with other fungicides and insecticides, highlighting the need to study pesticide mixtures that occur in surface waters. For fungicides that partition to

  9. Recurrent sublethal warming reduces embryonic survival, inhibits juvenile growth, and alters species distribution projections under climate change.

    Science.gov (United States)

    Carlo, Michael A; Riddell, Eric A; Levy, Ofir; Sears, Michael W

    2018-01-01

    The capacity to tolerate climate change often varies across ontogeny in organisms with complex life cycles. Recently developed species distribution models incorporate traits across life stages; however, these life-cycle models primarily evaluate effects of lethal change. Here, we examine impacts of recurrent sublethal warming on development and survival in ecological projections of climate change. We reared lizard embryos in the laboratory under temperature cycles that simulated contemporary conditions and warming scenarios. We also artificially warmed natural nests to mimic laboratory treatments. In both cases, recurrent sublethal warming decreased embryonic survival and hatchling sizes. Incorporating survivorship results into a mechanistic species distribution model reduced annual survival by up to 24% compared to models that did not incorporate sublethal warming. Contrary to models without sublethal effects, our model suggests that modest increases in developmental temperatures influence species ranges due to effects on survivorship. © 2017 John Wiley & Sons Ltd/CNRS.

  10. Effects of organic and inorganic amendments on soil erodibility

    Directory of Open Access Journals (Sweden)

    Nutullah Özdemir

    2015-10-01

    Full Text Available The objective of the present investigation is to find out the effect of incorporating of various organic and inorganic matter sources such as lime (L, zeolit (Z, polyacrylamide (PAM and biosolid (BS on the instability index. A bulk surface (0–20 cm depth soil sample was taken from Samsun, in northern part of Turkey. Some soil properties were determined as follows; fine in texture, modarete in organic matter content, low in pH and free of alkaline problem. The soil samples were treated with the inorganic and organic materials at four different levels including the control treatments in a randomized factorial block design. The soil samples were incubated for ten weeks. After the incubation period, corn was grown in all pots. The results can be summarized as organic and inorganic matter treatments increased structure stability and decreased soil erodibility. Effectiveness of the treatments varied depending on the types and levels of organic and inorganic materials.

  11. Salt Efflorescence Effects on Soil Surface Erodibility and Dust Emissions

    Science.gov (United States)

    Van Pelt, R. S.; Zhang, G.

    2017-12-01

    Soluble salts resulting from weathering of geological materials often form surface crusts or efflorescences in areas with shallow saline groundwater. In many cases, the affected areas are susceptible to wind erosion due to their lack of protective vegetation and their flat topography. Fugitive dusts containing soluble salts affect the biogeochemistry of deposition regions and may result in respiratory irritation during transport. We created efflorescent crusts on soil trays by surface evaporation of single salt solutions and bombarded the resultant efflorescences with quartz abrader sand in a laboratory wind tunnel. Four replicate trays containing a Torrifluvent soil affected by one of nine salts commonly found in arid and semiarid streams were tested and the emissions were captured by an aspirated multi-stage deposition and filtering system. We found that in most cases the efflorescent crust reduced the soil surface erodibility but also resulted in the emission of salt rich dust. Two of the salts, sodium thiosulfate and calcium chloride, resulted in increased soil volume and erodibility. However, one of the calcium chloride replicates was tested after an outbreak of humid air caused hygroscopic wetting of the soil and it became indurated upon drying greatly decreasing the erodibility. Although saline affected soils are not used for agricultural production and degradation is not a great concern, the release of salt rich dust is an area of environmental concern and steps to control the dust emissions from affected soils should be developed. Future testing will utilize suites of salts found in streams of arid and semiarid regions.

  12. Relationship between Sublethal Injury and Inactivation of Yeast Cells by the Combination of Sorbic Acid and Pulsed Electric Fields▿

    OpenAIRE

    Somolinos, M.; García, D.; Condón, S.; Mañas, P.; Pagán, R.

    2007-01-01

    The objective of this study was to investigate the occurrence of sublethal injury after the pulsed-electric-field (PEF) treatment of two yeasts, Dekkera bruxellensis and Saccharomyces cerevisiae, as well as the relation of sublethal injury to the inactivating effect of the combination of PEF and sorbic acid. PEF caused sublethal injury in both yeasts: more than 90% of surviving D. bruxellensis cells and 99% of surviving S. cerevisiae cells were sublethally injured after 50 pulses at 12 kV/cm ...

  13. The assessment of sublethal effects of pollutants in the sea. Review of the problems.

    Science.gov (United States)

    Waldichuk, M

    1979-08-08

    Sublethal effects of pollution may be significant to survival of a stock of marine fish or even a species. Such effects sometimes lead to reproductive failure and have been identified so far only in freshwater systems. Atlantic salmon have disappeared from many streams in Europe and eastern North America, partly as a result of pollution in their freshwater spawning areas and in their estuarine nursing grounds. Reductions in populations of marine fishes due to pollution solely have not yet been demonstrated. However, Baltic Sea seals, where reproductive failure is apparently associated with high concentrations of DDT and polychlorinated biphenyl in the blubber, may have suffered a decline owing to the presence of these organochlorines. Sublethal effects of pollutants have been studied in the laboratory, essentially under four categories: (1) physiology (growth, swimming performance, respiration, circulation); (2) biochemistry/cell structure (blood chemistry, enzyme activity, endocrinology, histochemistry); (3) behaviour/neurophysiology; and (4) reproduction. Not all pollutants elicit meaningful responses in all categories, and a response is not always linear with pollutant concentration. For application to survival of populations the response has to be ultimately related to a healthy progression through a full life cycle, including successful reproduction. In recent time, physiological studies have moved into polluted marine environments with mobile laboratories having continuous sampling capability, to observe effects of pollutants in situ on marine organisms. The Controlled Ecosystem Pollution Experiment (Cepex) in Saanich Inlet, British Columbia, endeavours to investigate the effects of low concentrations of pollutants on marine organisms in large plastic silos having a slow replacement of water.

  14. Sublethal effects of clothianidin and Nosema spp. on the longevity and foraging activity of free flying honey bees.

    Science.gov (United States)

    Odemer, Richard; Nilles, Lisa; Linder, Nadine; Rosenkranz, Peter

    2018-03-19

    Neonicotinoids alone or in combination with pathogens are considered to be involved in the worldwide weakening of honey bees. We here present a new approach for testing sublethal and/or synergistic effects in free flying colonies. In our experiment individually marked honey bees were kept in free flying mini-hives and chronically exposed to sublethal doses of the neonicotinoid clothianidin. Additional groups of bees were challenged with Nosema infections or with combinations of the pesticide and pathogens. Longevity and flight activity of the differentially treated bees were monitored for a period of 18 days. In contrast to previous laboratory studies, no effect of the neonicotinoid treatment on mortality or flight activity could be observed. Although the lifespan of Nosema infected bees were significantly reduced compared to non-infected bees a combination of pesticide and pathogen did not reveal any synergistic effect. Our results indicate that individual bees are less impaired by neonicotinoids if kept within the social environment of the colony. The effect of such a "social buffering" should be considered in future risk assessments.

  15. Impacts of Sublethal Mercury Exposure on Birds: A Detailed Review.

    Science.gov (United States)

    Whitney, Margaret C; Cristol, Daniel A

    Mercury is a ubiquitous environmental contaminant known to accumulate in, and negatively affect, fish-eating and oceanic bird species, and recently demonstrated to impact some terrestrial songbirds to a comparable extent. It can bioaccumulate to concentrations of >1 μg/g in tissues of prey organisms such as fish and insects. At high enough concentrations, exposure to mercury is lethal to birds. However, environmental exposures are usually far below the lethal concentrations established by dosing studies.The objective of this review is to better understand the effects of sublethal exposure to mercury in birds. We restricted our survey of the literature to studies with at least some exposures >5 μg/g. The majority of sublethal effects were subtle and some studies of similar endpoints reached different conclusions. Strong support exists in the literature for the conclusion that mercury exposure reduces reproductive output, compromises immune function, and causes avoidance of high-energy behaviors. For some endpoints, notably certain measures of reproductive success, endocrine and neurological function, and body condition, there is weak or contradictory evidence of adverse effects and further study is required. There was no evidence that environmentally relevant mercury exposure affects longevity, but several of the sublethal effects identified likely do result in fitness reductions that could adversely impact populations. Overall, 72% of field studies and 91% of laboratory studies found evidence of deleterious effects of mercury on some endpoint, and thus we can conclude that mercury is harmful to birds, and the many effects on reproduction indicate that bird population declines may already be resulting from environmental mercury pollution.

  16. Sublethal Heavy Metal Stress Stimulates Innate Immunity in Tomato

    Directory of Open Access Journals (Sweden)

    Nilanjan Chakraborty

    2015-01-01

    Full Text Available Effect of sublethal heavy metal stress as plant biotic elicitor for triggering innate immunity in tomato plant was investigated. Copper in in vivo condition induced accumulation of defense enzymes like peroxidase (PO, polyphenol oxidase (PPO, phenylalanine ammonia-lyase (PAL, and β-1,3 glucanase along with higher accumulation of total phenol, antioxidative enzymes (catalase and ascorbate peroxidase, and total chlorophyll content. Furthermore, the treatment also induced nitric oxide (NO production which was confirmed by realtime visualization of NO burst using a fluorescent probe 4,5-diaminofluorescein diacetate (DAF-2DA and spectrophotometric analysis. The result suggested that the sublethal dose of heavy metal can induce an array of plant defense responses that lead to the improvement of innate immunity in plants.

  17. The sublethal effects of the organochlorines dieldrin and lindane on growth and reproduction of Eudrilus eugeniae and Eisenia fetida (Oligochaeta

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1994-07-01

    Full Text Available Experimental exposure of the earthworm species Eudrilus eugeniae to organochlorines showed that dieldrin causes damage to sperm ultrastructure when viewed electronmicroscopically. Worms containing concentrations of 7,27 mg/kg dieldrin and higher showed more than 10% sperm damage. Exposure of Eisenia fetida to sublethal concentrations of lindane did not result in sperm damage but demonstrated an increase in growth and reproductive activity. It is argued that quantification of sperm damage and correlation with pesticide concentration could provide a useful tool for evaluating environmental quality. Furthermore, the effects of sublethal concentrations of pesticides that manifest themselves in increased growth and reproductive activity could affect ecological balances.

  18. Evaluation of Pyrethrin Formulations on Dengue/Dengue Haemorrhagic Fever Vectors in the Laboratory and Sublethal Effects

    Directory of Open Access Journals (Sweden)

    S Sulaiman

    2007-12-01

    Full Text Available In Southeast Asia, Aedes aegypti (L. has been incriminated as principal vector of dengue viruses and Ae. albopictus as the secondary vector of dengue fever. Therefore, the aim of this study was to investigate the effectiveness of three for-mula¬tions of pyrethrin derived from Tanacetum cinerariaefolium against the dengue/dengue haemorrhagic fever vectors Aedes aegypti and Ae. albopictus in the laboratory. The testings employed 2 methodologies: the WHO Larval Bioassay and WHO Adult Bioassay. The results showed that all the three pyrethrin formulations had larvicidal and adulticidal activi-ties. The impact of the sublethal doses of pyrethrin formulations on Aedes spp. larvae resulted in 4-6% of alive adult emergence compared to 90% of Ae. aegypti emerging adults and 96% Ae. albopictus alive adult emergence in the control. The impact of sublethal doses of the pyrethrin formulations caused very low fecundity on both Aedes spp. compared to the control (P< 0.05.

  19. Evaluation of Pyrethrin Formulations on Dengue/Dengue Haemorrhagic Fever Vectors in the Laboratory and Sublethal Effects

    Directory of Open Access Journals (Sweden)

    S Sulaiman

    2007-11-01

    Full Text Available In Southeast Asia, Aedes aegypti (L. has been incriminated as principal vector of dengue viruses and Ae. albopictus as the secondary vector of dengue fever. Therefore, the aim of this study was to investigate the effectiveness of three for-mula¬tions of pyrethrin derived from Tanacetum cinerariaefolium against the dengue/dengue haemorrhagic fever vectors Aedes aegypti and Ae. albopictus in the laboratory. The testings employed 2 methodologies: the WHO Larval Bioassay and WHO Adult Bioassay. The results showed that all the three pyrethrin formulations had larvicidal and adulticidal activi-ties. The impact of the sublethal doses of pyrethrin formulations on Aedes spp. larvae resulted in 4-6% of alive adult emergence compared to 90% of Ae. aegypti emerging adults and 96% Ae. albopictus alive adult emergence in the control. The impact of sublethal doses of the pyrethrin formulations caused very low fecundity on both Aedes spp. compared to the control (P< 0.05.

  20. Using photopigment biomarkers to quantify sub-lethal effects of petroleum pollution on natural phytoplankton assemblages

    International Nuclear Information System (INIS)

    Swistak, J.; Pinckney, J.; Piehler, M.; Paerl, H.

    1995-01-01

    Although much work has been undertaken to determine the toxicity of petroleum pollutants to phytoplankton, most studies have used pure cultures to monitor growth of selected phytoplankton species. Fewer have considered the net effect on entire microalgal communities. Using high performance liquid chromatography (HPLC) to characterize diagnostic microalgal pigments, the authors were able to simultaneously assess sub-lethal pollutant effects on entire communities as well as on individual phytoplankton functional groups. Incubations of natural water samples with diesel fuel, an important contributor to coastal petroleum pollution, revealed significant changes in photopigments and relative abundance of taxonomic groups at sub-lethal concentrations. Differential rates of change of indicator pigment concentrations suggest a range of sensitivity among phytoplankton groups. In preliminary experiments, cyanobacteria exhibited the greatest overall tolerance to the diesel fuel concentrations tested, while cryptomonads displayed the most sensitivity. The authors are currently evaluating the responses of seasonal phytoplankton populations from 3 sites exposed to varied levels of petroleum pollution. HPLC will be used to characterize phytoplankton populations and to determine if the most abundant groups are also the most tolerant of diesel fuel. Preliminary experiments indicate that diesel fuel pollution may modify the structure and function of phytoplankton communities and subsequently alter the trophodynamics of impacted systems

  1. Biochemical and Hematological Profiles of Common Carp (Cyprinus Carpio under Sublethal Effects of Trivalent Chromium

    Directory of Open Access Journals (Sweden)

    Zeynab Abedi

    2016-07-01

    Full Text Available Background: In natural waters and/or aquaculture facilities, fish are often exposed to chromium waste and demonstrate cumulative deleterious effects. To our knowledge, there are no studies concerning the effects of trivalent Cr on C. carpio hematology. This study presents hematological and some biochemical parameters of common carp, Cyprinus carpio, affected by sublethal concentration of trivalent chromium. Methods: The fish in the experimental aquaria (three replicates each were exposed to a sublethal chromium chloride concentration of 2 mg L−1, which was prepared as stock solution and added depending on the volume of the aquaria to obtain the required concentration. After a period of 28 days, parameters such as hematocrit (Hct, hemoglobin (Hb, lymphocytes (Lym, neutrophils (Neu, total protein (TP, albumin, immunoglobulin M (IgM, glucose, red and white blood cells (RBC and WBC, mean corpuscular volume (MCV, mean corpuscular hemoglobin (MCH, and mean corpuscular hemoglobin concentration (MCHC were examined. Results: Chromium exposure for 28 days significantly (P0.05 between the Cr-exposed fish and the control. Conclusion: Hematological indices of fish, caused by chromium toxicity to C. carpio, can be secondary responses to toxicants, including exposure to low concentrations of heavy metals, which reflect the launch of stress reaction in the affected fish.

  2. Effects of Sublethal Concentrations of Insecticides on the Functional Response of Two Mirid Generalist Predators.

    Directory of Open Access Journals (Sweden)

    Angeliki F Martinou

    Full Text Available The use of agrochemicals particularly pesticides, can hamper the effectiveness of natural enemies, causing disruption in the ecosystem service of biological control. In the current study, the effects of the insecticides thiacloprid and chlorantraniliprole on the functional response curves were assessed for two mirid predator nymphs, Macrolophus pygmaeus Rambur and Nesidiocoris tenuis Reuter. In the absence of insecticides, both predators exhibited a type II functional response when feeding on eggs of the moth Ephestia kuehniella. N. tenuis seems to be a more efficient predator than M. pygmaeus, as model estimated handling time was significantly lower for the former than for the latter. Residual exposure of M. pygmaeus to sublethal concentrations of either insecticide was associated with a change in the asymptote but not the type of the functional response curve. Thiacloprid seems to be the least compatible with M. pygmaeus, as it led to both a significant reduction of the attack rate and an increase in handling time. In contrast, chlorantraniliprole exposure significantly increased the handling time, but not the attack rate of the predator. Residual exposure of N. tenuis to sublethal concentrations of either insecticide did not have a significant effect on the type nor the parameters of the functional response model. The results show that pesticide residues that do not have lethal effects on beneficial arthropods can reduce prey consumption depending on predator species and on likely risks associated with toxicity.

  3. Effects of Sublethal Concentrations of Insecticides on the Functional Response of Two Mirid Generalist Predators.

    Science.gov (United States)

    Martinou, Angeliki F; Stavrinides, Menelaos C

    2015-01-01

    The use of agrochemicals particularly pesticides, can hamper the effectiveness of natural enemies, causing disruption in the ecosystem service of biological control. In the current study, the effects of the insecticides thiacloprid and chlorantraniliprole on the functional response curves were assessed for two mirid predator nymphs, Macrolophus pygmaeus Rambur and Nesidiocoris tenuis Reuter. In the absence of insecticides, both predators exhibited a type II functional response when feeding on eggs of the moth Ephestia kuehniella. N. tenuis seems to be a more efficient predator than M. pygmaeus, as model estimated handling time was significantly lower for the former than for the latter. Residual exposure of M. pygmaeus to sublethal concentrations of either insecticide was associated with a change in the asymptote but not the type of the functional response curve. Thiacloprid seems to be the least compatible with M. pygmaeus, as it led to both a significant reduction of the attack rate and an increase in handling time. In contrast, chlorantraniliprole exposure significantly increased the handling time, but not the attack rate of the predator. Residual exposure of N. tenuis to sublethal concentrations of either insecticide did not have a significant effect on the type nor the parameters of the functional response model. The results show that pesticide residues that do not have lethal effects on beneficial arthropods can reduce prey consumption depending on predator species and on likely risks associated with toxicity.

  4. Bonding stability of adhesive systems to eroded dentin

    Directory of Open Access Journals (Sweden)

    Janaina Barros CRUZ

    2015-01-01

    Full Text Available This in vitro study evaluated the immediate and 6 months microshear bond strength (µSBS of different adhesive systems to sound and eroded dentin. Sixty bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated into two groups: sound dentin (immersion in artificial saliva and eroded dentin (erosive challenge following a pH cycling model comprising 4 ×/day Sprite Light® drink for 10 days. Then, specimens were reassigned according to the adhesive system: etch-and-rinse adhesive (Adper Single Bond, two-step self-etch system (Clearfil SE Bond, or one-step self-etch adhesive (Adper Easy One. Polyethylene tubes with an internal diameter of 0.76 mm were placed over pre-treated dentin and filled with resin composite (Z250. Half of the specimens were evaluated by the µSBS test after 24 h, and the other half 6 months later, after water storage at 37°C. Failure mode was evaluated using a stereomicroscope (400×. Data were analyzed by three-way repeated measures analysis of variance and Tukey’s post hoc tests (α = 0.05. After 6 months of water aging, marked reductions in µSBS values were observed, irrespective of the substrate. The µSBS values for eroded dentin were lower than those obtained for sound dentin. No difference in bonding effectiveness was observed among adhesive systems. For all groups, adhesive/mixed failure was observed. In conclusion, eroded dentin compromises the bonding quality of adhesive systems over time.

  5. 7 CFR 12.20 - NRCS responsibilities regarding highly erodible land.

    Science.gov (United States)

    2010-01-01

    ... WETLAND CONSERVATION Highly Erodible Land Conservation § 12.20 NRCS responsibilities regarding highly... public lists of highly erodible soil map units; (c) Make soil surveys for purposes of identifying highly erodible land; and (d) Provide technical guidance to conservation districts which approve conservation...

  6. Differential effects of biochar on soils within an eroded field

    Science.gov (United States)

    Schumacher, Thomas; Chintala, Rajesh; Sandhu, Saroop; Kumar, Sandeep; Clay, Dave; Gelderman, Ron; Papiernik, Sharon; Malo, Douglas; Clay, Sharon; Julson, Jim

    2015-04-01

    Future uses of biochar will in part be dependent not only on the effects of biochar on soil processes but also on the availability and economics of biochar production. If pyrolysis for production of bio-oil and syngas becomes wide-spread, biochar as a by-product of bio-oil production will be widely available and relatively inexpensive compared to the production of biochar as primary product. Biochar produced as a by-product of optimized bio-oil production using regionally available feedstocks was examined for properties and for use as an amendment targeted to contrasting soils within an eroded field in an on-farm study initiated in 2013 at Brookings, South Dakota, USA. Three plant based biochar materials produced from carbon optimized gasification of corn stover (Zea mays L.), Ponderosa pine (Pinus ponderosa Lawson and C. Lawson) wood residue, and switchgrass (Panicum virgatum L.) were applied at a 1% (w/w) rate to a Maddock soil (Sandy, Mixed, Frigid Entic Hapludolls) located in an eroded upper landscape position and a Brookings soil (Fine-Silty, Mixed, Superactive, Frigid Pachic Hapludolls) located in a depositional landscape position. The cropping system within this agricultural landscape was a corn (Zea mays L.) and soybean (Glycine max L.) rotation. Biochar physical and chemical properties for each of the feedstocks were determined including pH, surface area, surface charge potential, C-distribution, ash content, macro and micro nutrient composition. Yields, nutrient content, and carbon isotope ratio measurements were made on the harvested seed. Soil physical properties measured included water retention, bulk density, and water infiltration from a ponded double ring infiltrometer. Laboratory studies were conducted to determine the effects of biochar on partitioning of nitrate and phosphorus at soil surface exchange complex and the extracellular enzymes activity of C and N cycles. Crop yields were increased only in the Maddock soil. Biochar interacted with each

  7. Biorock Electric Reefs Grow Back Severely Eroded Beaches in Months

    Directory of Open Access Journals (Sweden)

    Thomas J. F. Goreau

    2017-10-01

    Full Text Available Severely eroded beaches on low lying islands in Indonesia were grown back in a few months—believed to be a record—using an innovative method of shore protection, Biorock electric reef technology. Biorock shore protection reefs are growing limestone structures that get stronger with age and repair themselves, are cheaper than concrete or rock sea walls and breakwaters, and are much more effective at shore protection and beach growth. Biorock reefs are permeable, porous, growing, self-repairing structures of any size or shape, which dissipate wave energy by internal refraction, diffraction, and frictional dissipation. They do not cause reflection of waves like hard sea walls and breakwaters, which erodes the sand in front of, and then underneath, such structures, until they collapse. Biorock reefs stimulate settlement, growth, survival, and resistance to the environmental stress of all forms of marine life, restoring coral reefs, sea grasses, biological sand production, and fisheries habitat. Biorock reefs can grow back eroded beaches and islands faster than the rate of sea level rise, and are the most cost-effective method of shore protection and adaptation to global sea level rise for low lying islands and coasts.

  8. The effect of postirradiation application of aspartic acid salts on hemopoietic recovery in sublethally X-irradiated mice

    International Nuclear Information System (INIS)

    Pospisil, M.; Netikova, J.; Vasku, J.; Urbanek, E.

    1979-01-01

    The effect of aspartic acid salts, especially of K and Mg aspartates, on certain hematological changes in the peripheral blood and hemopoietic organs of sublethally X-irratiated male mice of the strain C57Bl/10 was investigated. Salts of aspartic acid were administered in tap water after irradiation. A favorable effect of aspartic acid salts on erythropoietic recovery and on regeneration of thymus weight was found during the first two weeks after irradiation. (orig.) [de

  9. Relationship between sublethal injury and inactivation of yeast cells by the combination of sorbic acid and pulsed electric fields.

    Science.gov (United States)

    Somolinos, M; García, D; Condón, S; Mañas, P; Pagán, R

    2007-06-01

    The objective of this study was to investigate the occurrence of sublethal injury after the pulsed-electric-field (PEF) treatment of two yeasts, Dekkera bruxellensis and Saccharomyces cerevisiae, as well as the relation of sublethal injury to the inactivating effect of the combination of PEF and sorbic acid. PEF caused sublethal injury in both yeasts: more than 90% of surviving D. bruxellensis cells and 99% of surviving S. cerevisiae cells were sublethally injured after 50 pulses at 12 kV/cm in buffer at pHs of both 7.0 and 4.0. The proportion of sublethally injured cells reached a maximum after 50 pulses at 12.0 kV/cm (S. cerevisiae) or 16.5 kV/cm (D. bruxellensis), and it kept constant or progressively decreased at greater electric field strengths and with longer PEF treatments. Sublethally PEF-injured cells showed sensitivity to the presence of sorbic acid at a concentration of 2,000 ppm. A synergistic inactivating effect of the combination of PEF and sorbic acid was observed. Survivors of the PEF treatment were progressively inactivated in the presence of 2,000 ppm of sorbic acid at pH 3.8, with the combined treatments achieving more than log10 5 cycles of dead cells under the conditions investigated. This study has demonstrated the occurrence of sublethal injury after exposure to PEF, so yeast inactivation by PEF is not an all-or-nothing event. The combination of PEF and sorbic acid has proven to be an effective method to achieve a higher level of yeast inactivation. This work contributes to the knowledge of the mechanism of microbial inactivation by PEF, and it may be useful for improving food preservation by PEF technology.

  10. Lethal and sublethal effects of azadirachtin and cypermethrin on Habrobracon hebetor (Hymenoptera: Braconidae).

    Science.gov (United States)

    Abedi, Zahra; Saber, Moosa; Gharekhani, Gholamhossein; Mehrvar, Ali; Kamita, Shizuo George

    2014-04-01

    Habrobracon hebetor Say is an ectoparasitoid of larval stage of various lepidopteran pests. Lethal and sublethal effects of azadirachtin and cypermethrin were evaluated on adult and preimaginal stages of H. hebetor under laboratory conditions. Contact exposure bioassays with adults indicated that the lethal concentration (LC50) of two commercial azadirachtin-containing formulations, NeemGuard and BioNeem, were 43.5 and 10.2 microg a.i./ml, respectively. The LC50 of cypermethrin was 5.4 microg a.i./ml. When larval stage of H. hebetor was exposed to these insecticides with a field recommended concentration of NeemGuard, BioNeem, or cypermethrin by a dip protocol, the emergence rate was reduced by 39.0, 36.6, and 97.6%, respectively. To assay the sublethal effects of these insecticides, adult wasps were exposed to an LC30 concentration of the insecticides, and then demographic parameters of the surviving wasps were determined. Fecundity, fertility, and parameters including the intrinsic rate of increase (r(m)) were affected negatively. The r(m) values following exposure to NeemGuard, BioNeem, cypermethrin, or mock treatment were 0.143, 0.149, 0.160, and 0.179, respectively, female offspring per female per day, respectively. The current study showed that cypermethrin had more acute toxicity on larval and adult stages of H. hebetor compared with azadirachin. The commercial formulations of azadirachtin and cypermethrin negatively affected most of the life table parameters of the parasitoid. Semifield and field studies are needed for obtaining more applicable results on combining H. hebetor and the tested insecticides for an integrated pest management-based strategy for crop protection.

  11. Sublethal Dosage of Imidacloprid Reduces the Microglomerular Density of Honey Bee Mushroom Bodies

    Science.gov (United States)

    Peng, Yi-Chan; Yang, En-Cheng

    2016-01-01

    The dramatic loss of honey bees is a major concern worldwide. Previous studies have indicated that neonicotinoid insecticides cause behavioural abnormalities and have proven that exposure to sublethal doses of imidacloprid during the larval stage decreases the olfactory learning ability of adults. The present study shows the effect of sublethal doses of imidacloprid on the neural development of the honey bee brain by immunolabelling synaptic units in the calyces of mushroom bodies. We found that the density of the synaptic units in the region of the calyces, which are responsible for olfactory and visual functions, decreased after being exposed to a sublethal dose of imidacloprid. This not only links a decrease in olfactory learning ability to abnormal neural connectivity but also provides evidence that imidacloprid damages the development of the nervous system in regions responsible for both olfaction and vision during the larval stage of the honey bee. PMID:26757950

  12. Investigation of ionizing sublethal doses effects on endogenous radioresistance background

    International Nuclear Information System (INIS)

    Kudryashov, Yu.B.; Goncharenko, E.N.; Antonova, S.V.; Akhalaya, M.Ya.; Bajzhumanov, A.A.; Shestakova, S.V.

    1997-01-01

    Sublethal doses of X-radiation (0.5 Gy and 1 Gy) caused the alterations in levels of main components of endogenous radioresistance background in rat tissues. There were demonstrated the decrease of serotonin content in stomach mocosa and spleen, adrenalin, noradrenalin and corticosteroids contents in adrenal glands, nonprotein thiols content in spleen and the increase of lipid peroxide level in serum on the 3-14 days after irradiation. The recovery of the investigated parameters was occurred to the 21 day after exposure. (author)

  13. Assessment of ground water contamination in Erode District ...

    African Journals Online (AJOL)

    admin

    A systematic study has been carried out to assess the water contamination and the effect of the tanneries and dyeing industries effluents on Erode District, Tamil Nadu. Ten (10) sampling locations were selected in and around industries. The water samples were collected from the selected sampling points. The samples ...

  14. Puerto Rico Soil Erodibility (Kffact)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Puerto Rico soil erodibility (Kffactor) - low values indicate low vulnerability to erosion, higher values mean higher susceptibility to runoff.

  15. Field-level sublethal effects of approved bee hive chemicals on Honey Bees (Apis mellifera L).

    Science.gov (United States)

    Berry, Jennifer A; Hood, W Michael; Pietravalle, Stéphane; Delaplane, Keith S

    2013-01-01

    In a study replicated across two states and two years, we tested the sublethal effects on honey bees of the miticides Apistan (tau fluvalinate) and Check Mite+ (coumaphos) and the wood preservative copper naphthenate applied at label rates in field conditions. A continuous covariate, a colony Varroa mite index, helped us disambiguate the effects of the chemicals on bees while adjusting for a presumed benefit of controlling mites. Mite levels in colonies treated with Apistan or Check Mite+ were not different from levels in non-treated controls. Experimental chemicals significantly decreased 3-day brood survivorship and increased construction of queen supercedure cells compared to non-treated controls. Bees exposed to Check Mite+ as immatures had higher legacy mortality as adults relative to non-treated controls, whereas bees exposed to Apistan had improved legacy mortality relative to non-treated controls. Relative to non-treated controls, Check Mite+ increased adult emergence weight. Although there was a treatment effect on a test of associative learning, it was not possible to statistically separate the treatment means, but bees treated with Apistan performed comparatively well. And finally, there were no detected effects of bee hive chemical on colony bee population, amount of brood, amount of honey, foraging rate, time required for marked released bees to return to their nest, percentage of released bees that return to the nest, and colony Nosema spore loads. To our knowledge, this is the first study to examine sublethal effects of bee hive chemicals applied at label rates under field conditions while disambiguating the results from mite control benefits realized from the chemicals. Given the poor performance of the miticides at reducing mites and their inconsistent effects on the host, these results defend the use of bee health management practices that minimize use of exotic hive chemicals.

  16. Field-level sublethal effects of approved bee hive chemicals on Honey Bees (Apis mellifera L.

    Directory of Open Access Journals (Sweden)

    Jennifer A Berry

    Full Text Available In a study replicated across two states and two years, we tested the sublethal effects on honey bees of the miticides Apistan (tau fluvalinate and Check Mite+ (coumaphos and the wood preservative copper naphthenate applied at label rates in field conditions. A continuous covariate, a colony Varroa mite index, helped us disambiguate the effects of the chemicals on bees while adjusting for a presumed benefit of controlling mites. Mite levels in colonies treated with Apistan or Check Mite+ were not different from levels in non-treated controls. Experimental chemicals significantly decreased 3-day brood survivorship and increased construction of queen supercedure cells compared to non-treated controls. Bees exposed to Check Mite+ as immatures had higher legacy mortality as adults relative to non-treated controls, whereas bees exposed to Apistan had improved legacy mortality relative to non-treated controls. Relative to non-treated controls, Check Mite+ increased adult emergence weight. Although there was a treatment effect on a test of associative learning, it was not possible to statistically separate the treatment means, but bees treated with Apistan performed comparatively well. And finally, there were no detected effects of bee hive chemical on colony bee population, amount of brood, amount of honey, foraging rate, time required for marked released bees to return to their nest, percentage of released bees that return to the nest, and colony Nosema spore loads. To our knowledge, this is the first study to examine sublethal effects of bee hive chemicals applied at label rates under field conditions while disambiguating the results from mite control benefits realized from the chemicals. Given the poor performance of the miticides at reducing mites and their inconsistent effects on the host, these results defend the use of bee health management practices that minimize use of exotic hive chemicals.

  17. Effects of sublethal exposure to metofluthrin on the fitness of Aedes aegypti in a domestic setting in Cairns, Queensland.

    Science.gov (United States)

    Buhagiar, Tamara S; Devine, Gregor J; Ritchie, Scott A

    2017-05-31

    Metofluthrin is highly effective at reducing biting activity in Aedes aegypti. Its efficacy lies in the rapid onset of confusion, knockdown, and subsequent kill of a mosquito. In the field, there are a variety of scenarios that might result in sublethal exposure to metofluthrin, including mosquitoes that are active at the margins of the chemical's lethal range, brief exposure as mosquitoes fly in and out of treated spaces or decreasing efficacy of the emanators with time. Sublethal effects are key elements of insecticide exposure and selection. The metofluthrin dose for each treatment group of male and female Ae. aegypti was controlled using exposure time intervals to a 10% active ingredient (AI) metofluthrin emanator. Room size and distance from the emanator for all groups was maintained at 3 m. In bioassay cages, male Ae. aegypti were exposed at 0, 5, 10, 20, 30 and 40-min intervals. Females were exposed in bioassay cages at 0, 10, 20, 30, 40 and 60-min intervals. Mortality rates and fecundity were observed between the exposure time groups for both sexes. Female Ae. aegypti exposed for 60 min had a significantly higher mortality rate (50%), after a 24-h recovery period, than other exposure times, 10, 20, 30 and 40 min (P metofluthrin exposure were as likely to produce viable eggs with an unexposed female as males that had not been exposed (P > 0.05). Regardless of sex, if a mosquito survived exposure, it would be as biologically successful as its unexposed counterpart. Portability of the metofluthrin emanator and delayed knockdown effects create opportunities for sublethal exposure and potential pyrethroid resistance development in Ae. aegypti, and should be taken into consideration in recommendations for field application of this product, including minimum exposure periods and a prescribed number of emanators per room based on volume.

  18. Sublethal effects of spirodiclofen, abamectin and pyridaben on life-history traits and life-table parameters of two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae).

    Science.gov (United States)

    Saber, Moosa; Ahmadi, Zeinab; Mahdavinia, Gholamreza

    2018-05-01

    Two-spotted spider mite, Tetranychus urticae Koch, is one of the economically most important pests on a wide range of crops in greenhouses and orchards worldwide. Control of T. urticae has been largely based on the use of acaricides. Sublethal effects of spirodiclofen, pyridaben and abamectin were studied on life-table parameters of T. urticae females treated with the acaricides. LC 25 values of spirodiclofen, abamectin and pyridaben (3.84, 0.04 and 136.96 µg a.i./ml, respectively) were used for sublethal studies. All acaricides showed significant effects on T. urticae biological parameters including developmental time, survival rate, and fecundity. The females treated with spirodiclofen, abamectin and pyridaben at LC 25 exhibited significantly reduced net reproductive rate (R 0 ), finite rate of increase (λ) and intrinsic rate of increase (r). The intrinsic rate of increase in spirodiclofen, abamectin and pyridaben treated groups and control were 0.0138, 0.0273, 0.039 and 0.2481 female offspring per female per day, respectively. The results indicated that sublethal concentrations of tested pesticides strongly affected the life characteristics of spider mite and consequently may influence mite population growth in future generations.

  19. Erodibility of waste (Loess) soils from construction sites under water and wind erosional forces.

    Science.gov (United States)

    Tanner, Smadar; Katra, Itzhak; Argaman, Eli; Ben-Hur, Meni

    2018-03-01

    Excess soils from construction sites (waste soils) become a problem when exposed to soil erosion by water or wind. Understanding waste soil erodibility can contribute to its proper reuse for various surface applications. The general objective of the study was to provide a better understanding of the effects of soil properties on erodibility of waste soils excavated from various depths in a semiarid region under rainfall and wind erosive forces. Soil samples excavated from the topsoil (0-0.3m) and subsoil layers (0.3-0.9 and >1m depths) were subjected to simulated rainfall and wind. Under rainfall erosive forces, the subsoils were more erodible than the topsoil, in contrast to the results obtained under wind erosive forces. Exchangeable sodium percentage was the main factor controlling soil erodibility (K i ) under rainfall, and a significant logarithmic regression line was found between these two parameters. In addition, a significant, linear regression was found between K i and slaking values for the studied soil samples, suggesting that the former can be predicted from the latter. Soil erodibility under wind erosion force was controlled mainly by the dry aggregate characteristics (mean weight diameter and aggregate density): their higher values in the subsoil layers resulted in lower soil erodibility compared to the topsoil. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. The abrasive effect of commercial whitening toothpastes on eroded enamel.

    Science.gov (United States)

    Mosquim, Victor; Martines Souza, Beatriz; Foratori Junior, Gerson Aparecido; Wang, Linda; Magalhães, Ana Carolina

    2017-06-01

    To evaluate the in vitro abrasive effect of commercial whitening toothpastes on eroded bovine enamel samples in respect to erosive tooth wear. 72 bovine crowns were embedded, polished and subjected to the baseline profile analysis. The samples were then protected in 2/3 of the enamel surface and were randomly assigned to six groups (n= 12/group): G1: Oral-B 3D White, G2: Close-up Diamond Attraction Power White, G3: Sorriso Xtreme White 4D, G4: Colgate Luminous White, G5: Crest (conventional toothpaste), G6:erosion only (control). All samples were submitted to an erosive pH cycling (4 x 90 seconds in 0.1% citric acid, pH 2.5, per day) and abrasive challenges (2 x 15 seconds, per day) for 7 days. After the first and the last daily cycles, the samples were subjected to abrasive challenges, using a toothbrushing machine, soft toothbrushes and slurry of the tested toothpastes (1.5 N). Between the challenges, the samples were immersed in artificial saliva. The final profile was obtained and overlaid to the baseline profile for the calculation of the erosive tooth wear (μm). The data were subjected to Kruskal-Wallis/Dunn tests (Penamel wear (3.68±1.06 μm), similarly to G3 (3.17± 0.80 μm) and G4 (3.44± 1.29 μm). G3 and G4 performed similarly between them and compared with G5 (2.35± 1.44 μm). G2 (1.51± 0.95 μm) and G6 (0.85± 0.36 μm) showed the lowest enamel wear, which did not differ between them and from G5. Oral-B 3D White showed the highest abrasive potential while Close-up Diamond Attraction Power White showed the lowest abrasive potential on eroded enamel in vitro. This study showed that some commercial whitening toothpastes, especially those containing pyrophosphate associated with hydrated silica, enhanced enamel erosive wear.

  1. sessment of ground water contamination in Erode District, Tamilnadu

    African Journals Online (AJOL)

    A systematic study has been carried out to assess the water contamination and the effect of the tanneries and dyeing industries effluents on Erode District, Tamil Nadu. Ten (10) sampling locations were selected in and around industries. The water samples were collected from the selected sampling points. The samples ...

  2. Wind erodibility of soils from North Darfur State

    International Nuclear Information System (INIS)

    Medani, G. H.; Mustafa, M. A.

    2003-01-01

    Wind erodibility of soils (WE) is a prime factor for the prediction, assessment and mapping of wind erosion. Hence, this study was undertaken to generate WE data and pertinent relationships for North Darfur State. Surface soil samples (0-3 cm) were collected from forty farms scattered all over the state. Non-erodible soil particles (NEP) (>0.84 mm in diameter), WE and various relevant physical and chemical soil properties were determined. Regression analysis showed that NEP significantly (p 2 =0.825), clay (r 2 =0.754), silt (r 2 =0.737) and clay/ (silt + sand) ratio (r 2 =0.663), and decreased with increase in sand (r 2 =0.761), (silt+sand) / clay ratio (r 2 =0.766) and (silt+sand) / (clay+organic matter) ratio (r 2 =0.811). The four basic soil properties and their ratios gave the reverse effects on WE with slightly lower coefficients of determinations. Although organic matter is a slightly better predictor of both NEP and WE than (Si+S)/ (C+OM) ratio, the latter is preferred because it integrates in addition to OM resilient soil properties. A multiple regression equation with a relatively high coefficient of determination (R 2 =0.830) may also be used for predicting NEP from knowledge of the four prime soil properties. These properties accounted for only 62% of the variation of WE, thus it is not recommended for prediction purposes. The determined wind erodibility groups correlated very well with those established else where.(Author)

  3. Effect of sublethal levels of ionizing radiation on a predator-prey interaction

    International Nuclear Information System (INIS)

    Chee, P.C.

    1976-01-01

    The predator-prey interaction studied was that between the largemouth bass (Micropterus salmoides) and the fathead minnow (Pimephales promelas) in an artificial test environment. Experiments were first conducted to determine the 50% lethal dose at 30 days of the minnow. Three different dose rates were used to test the effect of dose rate on the 50% lethal dose value. After the 50% lethal dose was determined the predator-prey interaction experiment was conducted using 30% of the 50% lethal dose as the highest radiation dose, this dose being considered the upper limit to sublethal radiation levels. A 4 x 4 Latin square design was chosen for the experiment, with four treatment levels (control plus three radiation levels) and four replicates. In each test 10 prey minnow were offered to one predator bass and the number of prey left after 14 days was the parameter of interest. A predator-prey interaction experiment using a single high level of radiation and two types of controls as conducted to ascertain the ability of the test environment to detect changes in the predator-prey interaction. The two types of controls were irradiated prey not exposed to predation and non-irradiated prey exposed to predation. An experiment was also conducted to test the correlation between the physical activity patterns of minnow and different doses of radiation. At a dose rate of 37.8 rad/min the 50% lethal dose at 30 days for minnow was found to be 2650 rad. It was found that dose rate had a strong influence on the 50% lethal dose. In the predator-prey interaction test it was found that the 14-day survival rate of prey was unaffected by sublethal levels of ionizing radiation. No significant correlation was detected between the physical activity patterns of minnow and radiation dose

  4. Relationship between soil erodibility and modeled infiltration rate in different soils

    Science.gov (United States)

    Wang, Guoqiang; Fang, Qingqing; Wu, Binbin; Yang, Huicai; Xu, Zongxue

    2015-09-01

    The relationship between soil erodibility, which is hard to measure, and modeled infiltration rate were rarely researched. Here, the soil erodibility factors (K and Ke in the USLE, Ki and K1 in the WEPP) were calculated and the infiltration rates were modeled based on the designed laboratory simulation experiments and proposed infiltration model, in order to build their relationship. The impacts of compost amendment on the soil erosion characteristics and relationship were also studied. Two contrasting agricultural soils (bare and cultivated fluvo-aquic soils) were used, and different poultry compost contents (control, low and high) were applied to both soils. The results indicated that the runoff rate, sediment yield rate and soil erodibility of the bare soil treatments were generally higher than those of the corresponding cultivated soil treatments. The application of composts generally decreased sediment yield and soil erodibility but did not always decrease runoff. The comparison of measured and modeled infiltration rates indicated that the model represented the infiltration processes well with an N-S coefficient of 0.84 for overall treatments. Significant negative logarithmic correlations have been found between final infiltration rate (FIR) and the four soil erodibility factors, and the relationship between USLE-K and FIR demonstrated the best correlation. The application of poultry composts would not influence the logarithmic relationship between FIR and soil erodibility. Our study provided a useful tool to estimate soil erodibility.

  5. Sublethal Effects of Fenoxycarb on the Plutella xylostella (Lepidoptera: Plutellidae).

    Science.gov (United States)

    Mahmoudvand, Mohammad; Moharramipour, Saeid

    2015-01-01

    The effects of fenoxycarb, a Juvenile hormone analogue, at sublethal concentrations were tested on some biological parameters of Plutella xylostella (L.) in two consecutive generations. The calculated LC10, LC25, and LC50 values of the insecticide were 21.58, 43.25, and 93.62 mg/liter on third-instar larvae, respectively. Fenoxycarb significantly reduced pupal weight and oviposition period in parent generation. In addition, the fecundity of treated groups (LC10 = 71.06, LC25 = 40.60 eggs per female) in parents was significantly lower than control (169.40 eggs per female). Although fenoxycarb could not affect gross reproductive rate and death rate, it decreased net reproductive rate, intrinsic rate of increase, finite rate of increase, and birth rate in offspring generation. Also, mean generation time and doubling time of treated insects was significantly longer than control at LC10 level. Therefore, the data from this study suggested that fenoxycarb could adversely cause population decline in the subsequent generation. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

  6. Sublethal effects of four insecticides on folding and spinning behavior in the rice leaffolder, Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae).

    Science.gov (United States)

    Yang, Yajun; Wang, Caiyun; Xu, Hongxing; Lu, Zhongxian

    2018-03-01

    The rice leaffolder, Cnaphalocrocis medinalis, is an important rice pest. The sublethal effects of chlorpyrifos, chlorantraniliprole, emamectin benzoate and spinosad were investigated on the folding and spinning behaviors of third- to fifth-instar C. medinalis larvae (L3 - L5) after insecticidal exposure of the second instar. A 25% lethal concentration (LC 25 ) of chlorpyrifos prolonged the leaf selection time of L5, and reduced the number of binds per primary fold for L4 and L5. An LC 10 of chlorantraniliprole reduced the number of binds per primary fold for L4 and increased the number of head swings per bind for L5. An LC 10 of emamectin benzoate shortened the primary fold length for L5 and decreased the number of head swings per primary fold for L3 and L4 and the number of head swings per bind for L3, while an LC 25 of emamectin benzoate shortened the fold length per 24 h for L5 and folding time for L3. An LC 10 of spinosad lowered the fold length per 24 h and the number of head swings for L5. An LC 25 of spinosad prolonged leaf selection time, and decreased primary fold length, binds per primary fold, binds per fold and fold length per 24 h in L5. Emamectin benzoate and spinosad exerted stronger sublethal effects on the folding and spinning behavior of C. medinalis than chlorpyrifos and chlorantraniliprole. These results provide better understanding of the sublethal effects of interactions of insecticides on C. medinalis. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. Morphodynamic modeling of erodible laminar channels.

    Science.gov (United States)

    Devauchelle, Olivier; Josserand, Christophe; Lagrée, Pierre-Yves; Zaleski, Stéphane

    2007-11-01

    A two-dimensional model for the erosion generated by viscous free-surface flows, based on the shallow-water equations and the lubrication approximation, is presented. It has a family of self-similar solutions for straight erodible channels, with an aspect ratio that increases in time. It is also shown, through a simplified stability analysis, that a laminar river can generate various bar instabilities very similar to those observed in natural rivers. This theoretical similarity reflects the meandering and braiding tendencies of laminar rivers indicated by F. Métivier and P. Meunier [J. Hydrol. 27, 22 (2003)]. Finally, we propose a simple scenario for the transition between patterns observed in experimental erodible channels.

  8. Effect of sublethal exposure of Cartap on hypothalamo-neurosecretory system of the freshwater spotted murrel, Channa punctatus (Bloch).

    Science.gov (United States)

    Mishra, D K; Bohidar, K; Pandey, A K

    2008-11-01

    In order to record the effect of carbamate pesticide on hypothalamus of Channa punctatus, fish were exposed to sublethal concentration (0.18 mg l(-1), 30% LC50 for 96 hr) of Cartap for 24, 48, 72 and 96 hr under static bioassay condition. Hypothalamo-neurosecretory complex of the murrel consisted mainly of nucleus preopticus (NPO), nucleus lateralis tuberis (NLT) and their axonal tracts. NPO is a paired structure situtated on either side of the third ventricle anterodorsal to the optic chiasma and looked inverted L-shape in the sagittal section. NPO is morphologically divisible into a dorsal pars magnocellularis (PMC) consisting of large neurons and ventral pars parvocellularis (PPC) formed of smaller neurosecretory cells. NLT cells are distributed in the infundibular floor adjacent to the pituitary stalk. Sublethal Cartap treatment induced an initial hypertrophy of the neurosecretory cells of NPO and NLT followed by loss of staining affinity as well as varying degrees of cytoplasmic vacuolization and necrosis. Herring bodies (HB) were also encountered in the neurohypophysis of the treated fishes.

  9. The effect of sub-lethal damage repair and exchange on the final slope of cell survival curves

    International Nuclear Information System (INIS)

    Carlone, M.C.; Wilkins, D.E.; Raaphorst, G.P.

    2003-01-01

    Full text: The Lea-Catcheside dose rate protraction factor, G, is the most widely used model to describe the effects of dose rate on cell survival. In the linear quadratic formalism, this factor modifies the beta component of cell killing; G is greatest for acute irradiations while vanishing at low dose rates. We have found a simple compartmental model that can derive the Lea-Catcheside function. This compartmental model clearly shows that the G function can only be derived using a little known assumption: the diminution of sub-lethal damage due to exchange of repairable lesions is negligible compared to that due to repair. This assumption was explicitly stated by Lea, but it does not appear to have been restated or verified since very early work on cell survival. The implication of this assumption is that sub-lethal damage can be modeled without considering exchange, which is evidenced by the fact that the G function does not contain parameters relating to exchange. By using a new model that fully accounts for repair and exchange of sublethal lesions, a cell survival expression that has a modified G function, but that retains the linear quadratic formalism, can be obtained. At low doses, this new model predicts linear-quadratic behavior, but the behavior gradually changes to mono-exponential at high doses, which is consistent with experimental observations. Modeling cell survival of well-known survival curves using the modified linear quadratic model shows statistically significant improvement in the fits to the cell survival data as compared to best fits obtained with the linear quadratic model. It is shown that these improvements in fits are due to a superior representation of the high dose region of the survival curve

  10. Radioprotective effect of chitosan in sub-lethally X-ray irradiated mice

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Yoshikazu; Ikota, Nobuo; Arima, Hiromi; Watanabe, Yoshito; Yukawa, Masae; Ozawa, Toshihiko [National Inst. of Radiological Sciences, Chiba (Japan); Kim, Hee-Sun [Korea Hydro and Nuclear Power Corp., Seoul (Korea, Republic of). Radiation Health Research Inst.; Bom, Hee-Seung; Kim, Young-Ho [Chonnam Univ., Kwangju (Korea, Republic of). Hospital

    2003-03-01

    The radioprotective effect of chitosan was studied in mice following whole-body X-ray irradiation. C3H/He mice were exposed to 7 Gy, and their survival rates were examined. The survival rates of chitosan-diet mice were about 20% higher than those of mice on a standard diet, and the rates dropped sharply to a plateau at day 10 after X-ray irradiation. The chitosan-diet mice had an increased weight ratio of spleen to body within the experimental period. The leukocyte, thrombocyte, and erythrocyte counts as well as the hematocrit and hemoglobin levels were recovered significantly and more rapidly in the chitosan-diet mice than the standard-diet mice at day 14 after irradiation. The scavenging abilities of chitosan were evaluated by the electron spin resonance (ESR) spin-trapping method. These observations suggested that chitosan led to hematopoetic activation and leuko-cytogenesis in mice after sub-lethal dose irradiation, and that the biological response might be caused by radical trapping or scavenging. (author)

  11. Frijolito Watershed: Integrated investigations of a rapidly eroding pinyon-juniper hillslope

    International Nuclear Information System (INIS)

    Wilcox, B.P.; Pitlick, J.

    1995-01-01

    The dramatic acceleration of erosion associated with the expansion of pinyon-juniper woodlands over the past 100 years has been widely recognized, but few process-based studies of this phenomenon have been undertaken. In an attempt to identify the underlying causes, and the factors that affect erosion processes, we have initiated an interdisciplinary study of a rapidly eroding pinyon-juniper woodland in northern New Mexico. Since July 1993, we have collected data on runoff, erosion, and weather conditions from a 1-ha catchment study area and have conducted surveys of topography, soils, and vegetation. Our preliminary results indicate that although runoff makes up less than 10% of the annual water budget, runoff events - which are frequent in the summer - are capable of moving large amounts of sediment. We estimate that between July 1993 and October 1994, between 25,000 and 50,000 kg of sediment has eroded and been transported from the catchment. The information gained from such studies is essential to our ability to formulate effective strategies for managing these rapidly eroding woodlands

  12. Migration of bone marrow cells to the thymus in sublethally irradiated mice

    International Nuclear Information System (INIS)

    Varlet, Andree; Lenaerts, Patrick; Houben-Defresne, M.P.; Boniver, Jacques

    1982-01-01

    In sublethally irradiated mice, thymus repopulation is due first to the proliferation of surviving thymocytes followed by the multiplication of bone marrow derived prothymocytes. The migration of bone marrow cells to the thymus after a single sublethal whole-body X irradiation was studied by using fluorescein isothiocyanate as a cell marker. Irradiation increases the permissiveness of the thymus to the immigration of bone marrow cells. Furthermore, the post-Rx regenerating bone marrow cells exhibit migration capacities greater than the normal ones. The radiation induced changes in the bone marrow thymus interaction might play an important role in thymus regeneration after sublethal irradiation [fr

  13. Sublethal effects of tritium on aquatic systems. Ecological effects of lithium and beryllium on aquatic communities. Teratological effects of low-level magnetic fields

    International Nuclear Information System (INIS)

    Strand, J.A.; Poston, T.M.; Skalaski, J.R.; Emery, R.M.; Klopfer, D.C.; Abernethy, C.S.

    1981-01-01

    Studies of the sublethal effects of tritium on the relatively radiosensitive immune process of the rainbow trout suggest that a higher RBE value than is now recognized by the International Commission on Radiological Protection (ICRP) may be required. Studies included an evaluation of potential toxicity of lithium on embryological life of rainbow trout and an assessment of fate and effects of lithium in artificial stream habitats. Levels of lithium necessary to cause an observed effect would have to be at least three orders of magnitude above observed background. Studies on teratogenic effects of low-level magnetic fields address the need to assess the potential harmful effects of magnetic fields on attendant personnel working in the transport and hot cell areas of fusion reactors

  14. Quantifying sublethal effects of glyphosate and Roundup® to Daphnia magna using a fluorescence based enzyme activity assay and video tracking

    DEFF Research Database (Denmark)

    Roslev, Peter; R. Hansen, Lone; Ørsted, Michael

    Glyphosate (N-(phosphonomethyl)glycine) is the active ingredient in a range of popular broad-spectrum, non-selective herbicide formulations. The toxicity of this herbicide to non-target aquatic organisms such as Daphnia magna is often evaluated using conventional toxicity assays that focus...... on endpoints such as immobility and mortality. In this study, we investigated sublethal effects of glyphosate and Roundup® to D. magna using video tracking for quantifying behavioral changes, and a novel fluorescence based assay for measuring in vivo hydrolytic enzyme activity (FLEA assay). Roundup® exposure...... resulted in concentration-dependent inhibition of alkaline phosphatase activity in D. magna. The inhibition of alkaline phosphatase by Roundup® was temperature-dependent with lowest inhibition at 14 °C and greater inhibition at 20 and 26 °C. Exposure of D. magna to sublethal concentrations of glyphosate...

  15. Effects of sub-lethal neurite outgrowth inhibitory concentrations of chlorpyrifos oxon on cytoskeletal proteins and acetylcholinesterase in differentiating N2a cells

    Energy Technology Data Exchange (ETDEWEB)

    Flaskos, J., E-mail: flaskos@vet.auth.gr [Laboratory of Biochemistry and Toxicology, School of Veterinary Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Nikolaidis, E. [Laboratory of Biochemistry and Toxicology, School of Veterinary Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Harris, W. [School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS (United Kingdom); Sachana, M. [Laboratory of Biochemistry and Toxicology, School of Veterinary Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Hargreaves, A.J., E-mail: alan.hargreaves@ntu.ac.uk [School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS (United Kingdom)

    2011-11-15

    Previous work in our laboratory has shown that sub-lethal concentrations (1-10 {mu}M) of chlorpyrifos (CPF), diazinon (DZ) and diazinon oxon (DZO) inhibit the outgrowth of axon-like neurites in differentiating mouse N2a neuroblastoma cells concomitant with altered levels and/or phosphorylation state of axonal cytoskeleton and growth-associated proteins. The aim of the present work was to determine whether chlorpyrifos oxon (CPO) was capable of inhibiting N2a cell differentiation in a similar manner. Using experimental conditions similar to our previous work, sub-lethal concentrations (1-10 {mu}M) of CPO were found to inhibit N2a cell differentiation. However, unlike previous studies with DZ and DZO, there was a high level of sustained inhibition of acetylcholinesterase (AChE) in CPO treated cells. Impairment of neurite outgrowth was also associated with reduced levels of growth associated protein-43 and neurofilament heavy chain (NFH), and the distribution of NFH in cells stained by indirect immunofluorescence was disrupted. However, in contrast to previous findings for DZO, the absolute level of phosphorylated NFH was unaffected by CPO exposure. Taken together, the findings suggest that sub-lethal concentrations of CPO inhibit axon outgrowth in differentiating N2a cells and that this effect involves reduced levels of two proteins that play key roles in axon outgrowth and maintenance. Although the inhibition of neurite outgrowth is unlikely to involve AChE inhibition directly, further work will help to determine whether the persistent inhibition of AChE by CPO can account for the different effects induced by CPO and DZO on the levels of total and phosphorylated NFH. -- Highlights: Black-Right-Pointing-Pointer Sub-lethal levels of chlorpyrifos oxon inhibit neurite outgrowth in N2a cells Black-Right-Pointing-Pointer Acetylcholinesterase exhibits sustained inhibition throughout exposure Black-Right-Pointing-Pointer The levels of neurofilament heavy chain and GAP-43

  16. Effects of sub-lethal neurite outgrowth inhibitory concentrations of chlorpyrifos oxon on cytoskeletal proteins and acetylcholinesterase in differentiating N2a cells

    International Nuclear Information System (INIS)

    Flaskos, J.; Nikolaidis, E.; Harris, W.; Sachana, M.; Hargreaves, A.J.

    2011-01-01

    Previous work in our laboratory has shown that sub-lethal concentrations (1–10 μM) of chlorpyrifos (CPF), diazinon (DZ) and diazinon oxon (DZO) inhibit the outgrowth of axon-like neurites in differentiating mouse N2a neuroblastoma cells concomitant with altered levels and/or phosphorylation state of axonal cytoskeleton and growth-associated proteins. The aim of the present work was to determine whether chlorpyrifos oxon (CPO) was capable of inhibiting N2a cell differentiation in a similar manner. Using experimental conditions similar to our previous work, sub-lethal concentrations (1–10 μM) of CPO were found to inhibit N2a cell differentiation. However, unlike previous studies with DZ and DZO, there was a high level of sustained inhibition of acetylcholinesterase (AChE) in CPO treated cells. Impairment of neurite outgrowth was also associated with reduced levels of growth associated protein-43 and neurofilament heavy chain (NFH), and the distribution of NFH in cells stained by indirect immunofluorescence was disrupted. However, in contrast to previous findings for DZO, the absolute level of phosphorylated NFH was unaffected by CPO exposure. Taken together, the findings suggest that sub-lethal concentrations of CPO inhibit axon outgrowth in differentiating N2a cells and that this effect involves reduced levels of two proteins that play key roles in axon outgrowth and maintenance. Although the inhibition of neurite outgrowth is unlikely to involve AChE inhibition directly, further work will help to determine whether the persistent inhibition of AChE by CPO can account for the different effects induced by CPO and DZO on the levels of total and phosphorylated NFH. -- Highlights: ► Sub-lethal levels of chlorpyrifos oxon inhibit neurite outgrowth in N2a cells ► Acetylcholinesterase exhibits sustained inhibition throughout exposure ► The levels of neurofilament heavy chain and GAP-43 protein are reduced ► Neurofilament heavy chain forms aggregates in cell

  17. Acute toxicity and sublethal effects of gallic and pelargonic acids on the zebrafish Danio rerio.

    Science.gov (United States)

    Techer, Didier; Milla, Sylvain; Fontaine, Pascal; Viot, Sandrine; Thomas, Marielle

    2015-04-01

    Gallic and pelargonic acids are naturally found in a variety of plants and food products. Despite their extensive use in man-made applications, little is known regarding their potential risks to aquatic vertebrates. The aim of this work was to assess the acute toxicity of these polyphenolic and fatty acid compounds to the zebrafish. In order to get insights into sublethal effects, the enzyme activity of usual biomarkers related to oxidative stress and biotransformation were also assessed in fish. These latter included total superoxide dismutase, catalase as well as total glutathione peroxidase for antioxidant defence mechanisms and glutathione S-transferase for biotransformation related enzyme. Gallic acid was practically non-toxic (96-h lethal concentration (LC50) > 100 mg/L) whereas pelargonic acid was slightly toxic (96-h LC50 of 81.2 mg/L). Moreover, biomarker analyses indicated enhanced superoxide dismutase activity in fish exposed to 20, 40 and 100 mg/L of gallic acid compared to control. A dose-dependent induction of glutathione peroxidase and glutathione S-transferase was reported following gallic acid exposure at the tested concentrations of 10, 20 and 40 mg/L, with the exception of 100 mg/L of substance where basal activity levels were reported. In the case of pelargonic acid, there was no change in antioxidant enzyme activity while an inhibition of glutathione S-transferase was observed from organisms exposed to 45, 58 and 76 mg/L of test solution. The results concerning sublethal effects on biological parameters of zebrafish highlighted thereby the need for further investigations following chronic exposure to both organic acids.

  18. Effects of land conversion from native shrub to pistachio orchard on soil erodibility in an arid region.

    Science.gov (United States)

    Yakupoglu, Tugrul; Gundogan, Recep; Dindaroglu, Turgay; Kara, Zekeriya

    2017-10-29

    Land-use change through degrading natural vegetation for agricultural production adversely affects many of soil properties particularly organic carbon content of soils. The native shrub land and grassland of Gaziantep-Adiyaman plateau that is an important pistachio growing eco-region have been cleared to convert into pistachio orchard for the last 50 to 60 years. In this study, the effects of conversion of natural vegetation into agricultural uses on soil erodibility have been investigated. Soil samples were collected from surface of agricultural fields and adjacent natural vegetation areas, and samples were analyzed for some soil erodibility indices such as dispersion ratio (DR), erosion ratio (ER), structural stability index (SSI), Henin's instability index (I s ), and aggregate size distribution after wet sieving (AggSD). According to the statistical evaluation, these two areas were found as different from each other in terms of erosion indices except for I s index (P < 0.001 for DR and ER or P < 0.01 for SSI). In addition, native shrub land and converted land to agriculture were found different in terms of AggSD in all aggregate size groups. As a contrary to expectations, correlation tests showed that there were no any interaction between soil organic carbon and measured erodibility indices in two areas. In addition, significant relationships were determined between measured variables and soil textural fractions as statistical. These obtaining findings were attributed to changing of textural component distribution and initial aggregate size distribution results from land-use change in the study area. Study results were explained about hierarchical aggregate formation mechanism.

  19. Effects of sublethal exposure to boric acid sugar bait on adult survival, host-seeking, bloodfeeding behavior, and reproduction of Stegomyia albopicta.

    Science.gov (United States)

    Ali, Arshad; Xue, Rui-De; Barnard, Donald R

    2006-09-01

    Effects of sublethal exposure to 0.1% boric acid sugar bait on adult survival, host-seeking, bloodfeeding behavior, and reproduction of Stegomyia albopicta were studied in the laboratory. Survival of males as well as females was significantly reduced when exposed to the bait, compared to control adults. The host-seeking and bloodfeeding activities in the baited females decreased, but the mean duration of blood engorgement (probing to voluntary withdrawal of proboscis) was not significantly different between the baited and control females. The landing and biting rates (human forearm) were significantly reduced in the baited females compared to nonbaited controls. Fecundity and fertility (based on number of laid eggs per female and percentage egg hatch, respectively) in the baited females were significantly reduced, and ovarian development was retarded. Sublethal exposure to sugar-based boric acid bait has the potential to reduce adult populations of St. albopicta.

  20. Soil erodibility mapping using three approaches in the Tangiers province –Northern Morocco

    Directory of Open Access Journals (Sweden)

    Hamza Iaaich

    2016-09-01

    Full Text Available Soil erodibility is a key factor in assessing soil loss rates. In fact, soil loss is the most occurring land degradation form in Morocco, affecting rural and urban vulnerable areas. This work deals with large scale mapping of soil erodibility using three mapping approaches: (i the CORINE approach developed for Europe by the JRC; (ii the UNEP/FAO approach developed within the frame of the United Nations Environmental Program for the Mediterranean area; (iii the Universal Soil Loss Equation (USLE K factor. Our study zone is the province of Tangiers, North-West of Morocco. For each approach, we mapped and analyzed different erodibility factors in terms of parent material, topography and soil attributes. The thematic maps were then integrated using a Geographic Information System to elaborate a soil erodibility map for each of the three approaches. Finally, the validity of each approach was checked in the field, focusing on highly eroded areas, by confronting the estimated soil erodibility and the erosion state as observed in the field. We used three statistical indicators for validation: overall accuracy, weighted Kappa factor and omission/commission errors. We found that the UNEP/FAO approach, based principally on lithofacies and topography as mapping inputs, is the most adapted for the case of our study zone, followed by the CORINE approach. The USLE K factor underestimated the soil erodibility, especially for highly eroded areas.

  1. Acute, sublethal, and combination effects of azadirachtin and Bacillus thuringiensis on the cotton bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Abedi, Zahra; Saber, Moosa; Vojoudi, Samad; Mahdavi, Vahid; Parsaeyan, Ehsan

    2014-02-26

    The cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a polyphagous and cosmopolitan insect pest that causes damage to various plants. In this study, the lethal and sublethal effects of azadirachtin and Bacillus thuringiensis Berliner sub sp . kurstaki (Bacillales: Bacillaceae) were evaluated on third instar H. armigera under laboratory conditions. The LC50 values of azadirachtin and Bt were 12.95 and 96.8 µg a.i./mL, respectively. A total mortality of 56.7% was caused on third instar larvae when LC20 values of the insecticides were applied in combination with each other. The LT50 values of azadirachtin and Bt were 4.8 and 3.6 days, respectively. The results of the sublethal study showed that the application of LC30 value of azadirachtin and Bt reduced the larval and pupal weight and increased larval and pupal duration of H. armigera. The longevity and fecundity of female adults were affected significantly by the insecticides. Female fecundity was reduced by the treatments, respectively. The lowest adult emergence ratio and pupation ratio were observed in the azadirachtin treatment. The results indicated that both insecticides have high potential for controlling of the pest. This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.

  2. Sublethal effects of fenpyroximate and pyridaben on two predatory mite species, Neoseiulus womersleyi and Phytoseiulus persimilis (Acari, Phytoseiidae).

    Science.gov (United States)

    Park, Jung-Joon; Kim, Minsik; Lee, Joon-Ho; Shin, Key-Il; Lee, Sung Eun; Kim, Jeong-Gyu; Cho, Kijong

    2011-07-01

    Laboratory bioassays were conducted to evaluate the sublethal effects of fenpyroximate and pyridaben on life-table parameters of two predatory mites species, Neoseiulus (= Amblyseius) womersleyi and Phytoseiulus persimilis. In these assays, young adult females were treated with three sublethal concentrations of each acaricide. The life-table parameters were calculated at each acaricide concentration, and compared using bootstrap procedures. For each acaricide, the LC(50) estimates for both species were similar, yet the two species exhibited completely different susceptibility when the population growth rate was used as the endpoint. Exposure to both acaricides reduced the net reproduction rate (R (o)) in a concentration-dependent manner and their EC(50)s were equivalent to less than LC(7). Two different scales of population-level endpoints were estimated to compare the total effect between the species and treatments: the first endpoint values were based on the net reproductive rate (fecundity λ) and the second endpoint values incorporated the mean egg hatchability into the net reproductive rate (vitality λ). The fecundity λ decreased in a concentration-dependent manner for both acaricide treatments, but the vitality λ decreased abruptly after treatment of N. womersleyi with pyridaben. The change in the patterns of λ revealed that the acaricide effects at the population level strongly depended on the life-history characteristics of the predatory mite species and the chemical mode of action. When the total effects of the two acaricides on N. womersleyi and P. persimilis were considered, fenpyroximate was found to be the most compatible acaricide for the augmentative release of N. womersleyi after treatment.

  3. Functional modifications of macrophage activity after sublethal irradiation

    International Nuclear Information System (INIS)

    Swartz, R.P.

    1982-01-01

    The modifications of macrophage activity following sublethal irradiation, both in vivo and in vitro, were studied using spreading and C3b-receptor-mediated ingestion assays. Nonelicited peritoneal washout cells were examined for changes in activity and selected population characteristics. The cells from irradiated mice were from a resident peritoneal population and not immigrating cells. The macrophage population showed enhanced activity early with a refractory period (24-48) when the macrophages were unresponsive to stimulation by irradiated lymphocytes. The enhanced activity was inversely dose dependent on macrophage. The lymphocytes showed a regulatory function(s) on the time post irradiation at which they were examined. Early lymphocytes exhibited the ability to enhance the activity of normal macrophages while lymphocytes removed 24 hours post irradiation could suppress the activity of already activated macrophages. The effect(s) of the various lymphocyte populations were reproduced with cell-free supernatants which was indicative of the production of lymphokines. Separation on nylon wool columns indicated that the activity resided primarily in the T-cell population of lymphocytes. In vitro irradiation indicated that stimulation of the lymphocytes is macrophage dependent. Additional work indicated that sublethally irradiated macrophages did not inhibit replication of the coccidian protozoon Toxoplasma gondii although they did show increased phagocytosis. Examination of the serum from whole body irradiated mice showed the presence of a postirradiation substance which enhanced the phagocytosis of normal macrophages. It was not present in the serum of normal mice and was not endotoxin

  4. Effect of indomethacin, diclofenac sodium and sodium salicylate on peripheral blood cell counts in sublethally gamma-irradiated mice

    International Nuclear Information System (INIS)

    Pospisil, M.; Netikova, J.; Kozubik, A.; Pipalova, I.

    1989-01-01

    Treatment with indomethacin and diclofenac sodium was found to increase granulocyte counts in the blood of sublethally gamma-irradiated mice. Treatment with sodium salicylate was ineffective in this respect, administration of sodium salicylate together with indomethacin even decreased the indomethacin-induced effects. The results suggest that the hemopoiesis-stimulating effects of non-steroidal anti-flammatory drugs cannot be correlated with the anti-inflammatory activity but rather with the side effects of these compounds, including the action on gastro-intestinal prostanoid production. This conclusion doubts on the possibility of the usefulness of non-steroidal anti-inflammatory drugs in conditions of the radiation syndrome. (orig.) [de

  5. Societal Forces That ERODE Creativity

    Science.gov (United States)

    Sternberg, Robert; Kaufman, James C.

    2018-01-01

    Background/Context: Creativity is an indispensable force in intellectual, social, cultural, and economic development. Yet societal forces conspire to erode it. Educators have despaired for many years over how schools often fail to encourage creativity, but society as a whole is just as guilty. But how do schools and society fail to encourage, or…

  6. Value-Eroding Teacher Behaviors Scale: A Validity and Reliability Study

    Science.gov (United States)

    Arseven, Zeynep; Kiliç, Abdurrahman; Sahin, Seyma

    2016-01-01

    In the present study, it is aimed to develop a valid and reliable scale for determining value-eroding behaviors of teachers, hence their values of judgment. The items of the "Value-eroding Teacher Behaviors Scale" were designed in the form of 5-point likert type rating scale. The exploratory factor analysis (EFA) was conducted to…

  7. 7 CFR 12.21 - Identification of highly erodible lands criteria.

    Science.gov (United States)

    2010-01-01

    ... the Universal Soil Loss Equation (USLE): (i) Rainfall and runoff (R); (ii) The degree to which the... and surface soil moisture (C) and the degree to which soil resists wind erosion (I). (3) The USLE is...) Basis for identification as highly erodible. Soil map units and an erodibility index will be used as the...

  8. Effects of the brominated flame retardants hexabromocyclododecane (HBCDD), and tetrabromobisphenol A (TBBPA), on hepatic enzymes and other biomarkers in juvenile rainbow trout and feral eelpout

    International Nuclear Information System (INIS)

    Ronisz, D.; Farmen Finne, E.; Karlsson, H.; Foerlin, L.

    2004-01-01

    Brominated flame retardants (BFRs) leak out in the environment, including the aquatic one. Despite this, sublethal effects of these chemicals are poorly investigated in fish. In this study, a screening of selected biomarkers in juvenile rainbow trout (Oncorhynchus mykiss) and feral eelpout (Zoarces viviparus) was performed after exposure to hexabromocyclododecane (HBCDD) and tetrabromobisphenol A (TBBPA). Rainbow trout was injected intraperitoneally (i.p.) with HBCDD or TBBPA. Two out of four short-term experiments with HBCDD showed an increase in the activity of catalase. A 40% increase in liver somatic index (LSI) could be observed after 28 days. HBCDD did also seem to have an inhibitory effect on CYP1A's activity (ethoxyresorufin-O-deethylase (EROD)). A putative peroxisome proliferating activity of the compound was investigated without giving a definite answer. HBCDD did not seem to be estrogenic or genotoxic. TBBPA increased the activity of glutathione reductase (GR) after 4, 14 and 28 days in rainbow trout suggesting a possible role of this compound in inducing oxidative stress. The compound did not seem to be estrogenic. TBBPA seemed to compete with the artificial substrate ethoxyresorufin in vitro, during the EROD assay. In eelpout, only one 5 days in vivo experiment was performed. Neither of the compounds gave rise to any effect in this fish. This was the first screening of sublethal effects of the two chemicals in fish, using high doses. Our results indicate that there is a need for further studies of long-term, low-dose effects of these two widely used flame retardants

  9. Dispersive and erodible soils - fundamental differences

    CSIR Research Space (South Africa)

    Paige-Green, P

    2008-11-01

    Full Text Available Dispersive, erodible and slaking soils are prevalent over wide areas of South Africa. Each of these materials increases the cost of construction, but dispersive soils are likely to lead to far more serious problems, particularly in dam construction...

  10. Sublethal effects of heavy metals on biochemical composition and their recovery in Indian major carps

    International Nuclear Information System (INIS)

    Garg, Smita; Gupta, R.K.; Jain, K.L.

    2009-01-01

    Studies were conducted to assess the effects of sublethal exposure of heavy metals cadmium, arsenic and zinc for 45 days on Indian major carps, Labeo rohita, Cirrhinus mrigala and Catla catla. Heavy metal treatments in general showed significant reduction in carbohydrate and lipid contents content in muscles as well as in gills in all the three fish species. The order of reduction of muscle and gill carbohydrate and lipid content due to different treatments was Cd + As + Zn > Cd + As > As + Zn > Cd + Zn > Cd > As > Zn. When fish were transferred to metal free water for 30 days, the level of carbohydrate and lipid contents improved considerably in all the three fish species

  11. Effects of sub-lethal dose of γ-irradiation on lysosomal enzymes in tissue of pigeon

    International Nuclear Information System (INIS)

    Shah, V.C.; Gadhia, P.K.

    1979-01-01

    Effects of total body γ-irradiation with sub-lethal dose (300 rad) on three lysosomal enzymes namely acid phosphatase, ribonuclease-II and deoxyribonuclease-II have been studied in pigeons. Liver, kidney and spleen were the tissues studied at different intervals like 1-h, 24-h, 48-h, and 72-h of irradiation. The specific activities ('crude' fraction) of acid phosphatase and ribonuclease-II increased significantly in spleen and liver at 48-h of irradiation. The activity of deoxyribonuclease-II in liver and spleen was increased only at 72-h post-irradiation. On the other hand, the total activities of three lysosomal enzymes did not show remarkable change throughout 72-h of irradiation. (author)

  12. Soil Erodibility for Water Pollution Management of Melaka Watershed in Peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    Md. Ibrahim Adham

    2015-07-01

    Full Text Available The relationships between surface runoffand soil erodibility are significant in water pollution and watershed management practices. Land use pattern, soil series and slope percentage are also major factors to develop the relationships. Daily rainfall data were collected and analyzed for variations in precipitation for calculating the surface runoff of these watersheds and surface runoff map was produced by GIS tools. Tew equation was utilized to predict soil erodibility of watershed soils.Results indicated that the weighted curve number varies from 82 to 85 and monthly runoff 23% to 30% among the five watersheds. Soil erodibility varies from 0.038 to 0.06 ton/ha (MJ.mm/ha/h. Linau-Telok-Local Alluvium, Malacca-Munchong, Munchong-Malacca-Serdang and Malacca-Munchong-Tavy are the dominant soil series of this region having the average soil erodibility of about 0.042 ton/ha (MJ.mm/ha/h. The main focus of this study is to provide the information of soil erodibility to reduce the water pollution of a watershed.

  13. An iso-erodent map Imo state of Nigeria | Madubuike | International ...

    African Journals Online (AJOL)

    Among inputs/resources often needed for erosion risk assessment of a region is the iso-erodent map of the region. This is a map showing areas of equal erosion potentials in the region. As Imo and Abia states of Nigeria lie in a high erosion region of the country, it was decided in this work to produce an iso-erodent map of ...

  14. U.S.V.I. Soil Erodibility (Kffact)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — U.S.V.I. soil erodibility (Kffactor) - low values indicate low vulnerability to erosion, higher values mean higher susceptibility to runoff.

  15. Biodiversity of soil bacteria exposed to sub-lethal concentrations of phosphonium-based ionic liquids: Effects of toxicity and biodegradation.

    Science.gov (United States)

    Sydow, Mateusz; Owsianiak, Mikołaj; Framski, Grzegorz; Woźniak-Karczewska, Marta; Piotrowska-Cyplik, Agnieszka; Ławniczak, Łukasz; Szulc, Alicja; Zgoła-Grześkowiak, Agnieszka; Heipieper, Hermann J; Chrzanowski, Łukasz

    2018-01-01

    Little is known about the effect of ionic liquids (ILs) on the structure of soil microbial communities and resulting biodiversity. Therefore, we studied the influence of six trihexyl(tetradecyl)phosphonium ILs (with either bromide or various organic anions) at sublethal concentrations on the structure of microbial community present in an urban park soil in 100-day microcosm experiments. The biodiversity decreased in all samples (Shannon's index decreased from 1.75 down to 0.74 and OTU's number decreased from 1399 down to 965) with the largest decrease observed in the microcosms spiked with ILs where biodegradation extent was higher than 80%. (i.e. [P 66614 ][Br] and [P 66614 ][2,4,4]). Despite this general decrease in biodiversity, which can be explained by ecotoxic effect of the ILs, the microbial community in the microcosms was enriched with Gram-negative hydrocarbon-degrading genera e.g. Sphingomonas. It is hypothesized that, in addition to toxicity, the observed decrease in biodiversity and change in the microbial community structure may be explained by the primary biodegradation of the ILs or their metabolites by the mentioned genera, which outcompeted other microorganisms unable to degrade ILs or their metabolites. Thus, the introduction of phosphonium-based ILs into soils at sub-lethal concentrations may result not only in a decrease in biodiversity due to toxic effects, but also in enrichment with ILs-degrading bacteria. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Effect of sublethal doses of radiation and cystamine on the dynamics of Rana temporaria L. larvae development

    International Nuclear Information System (INIS)

    Popov, D.V.

    1979-01-01

    The longevity of Rana temporaria L. larvae in the 45th stage of development is studied after irradiation in sublethal doses (10.000-20.000 R) and irradiation with preliminary cystamine protection. It has been shown that the protective effect of cystamine is revealed in partial normalization of the larvae development rate but does not eliminate the typical anomalies of extremity development and does not prolong the time of animal survival. It has been found that LD 50/30 dose for R. temporaria tadpoles in the 45th stage of development is slightly higher than 10.000 R. The selective effect of X-radiation on the formative bonds at cornea induction in Anura larvae is concluded

  17. Assessment of acute sublethal effects of clothianidin on motor function of honeybee workers using video-tracking analysis.

    Science.gov (United States)

    Alkassab, Abdulrahim T; Kirchner, Wolfgang H

    2018-01-01

    Sublethal impacts of pesticides on the locomotor activity might occur to different degrees and could escape visual observation. Therefore, our objective is the utilization of video-tracking to quantify how the acute oral exposure to different doses (0.1-2ng/bee) of the neonicotinoid "clothianidin" influences the locomotor activity of honeybees in a time course experiment. The total distance moved, resting time as well as the duration and frequency of bouts of laying upside down are measured. Our results show that bees exposed to acute sublethal doses of clothianidin exhibit a significant increase in the total distance moved after 30 and 60min of the treatment at the highest dose (2ng/bee). Nevertheless, a reduction of the total distance is observed at this dose 90min post-treatment compared to the distance of the same group after 30min, where the treated bees show an arched abdomen and start to lose their postural control. The treated bees with 1ng clothianidin show a significant increase in total distance moved over the experimental period. Moreover, a reduction in the resting time and increase of the duration and frequency of bouts of laying upside down at these doses are found. Furthermore, significant effects on the tested parameters are observed at the dose (0.5ng/bee) first at 60min post-treatment compared to untreated bees. The lowest dose (0.1ng/bee) has non-significant effects on the motor activity of honeybees compared to untreated bees over the experimental period. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Interactions between Entomopathogenic Fungus, Metarhizium Anisopliae and Sublethal Doses of Spinosad for Control of House Fly, Musca Domestica

    Directory of Open Access Journals (Sweden)

    M Sharififard

    2011-06-01

    Full Text Available Background: Metarhizium anisopliae strain IRAN 437C is one of the most virulent fungal isolates against house fly, Musca domestica. The objective of this study was to determine the interaction of this isolate with sublethal doses of spino­sad against housefly.Methods: In adult bioassay, conidia of entomopathogenic fungus were applied as inoculated bait at 105 and 107 spore per gram and spinosad at 0.5, 1 and 1.5 µg (A.I. per gram bait. In larval bioassay, conidia were applied as combina­tion of spore with larval bedding at 106 and 108 spore per gram and spinosad at sublethals of 0.002, 0.004 and 0.006 µg (AI per gram medium. Results: Adult mortality was 48% and 72% for fungus alone but ranged from 66–87% and 89–95% in combination treat­ments of 105 and 107 spore/g with sublethal doses of spinosad respectively. The interaction between 105 spore/g with sublethals exhibited synergistic effect, but in combination of 107 spore in spite of higher mortality, the interac­tion was additive. There was significant difference in LT50 among various treatments. LT50 values in all combination treat­ments were smaller than LT50 values in alone ones. Larval mortality was 36% and 69% for fungus alone but ranged from 58%–78% and 81%–100% in combination treatments of 106 and 108 spore/g medium with sublethals of spino­sad respectively. The interaction was synergistic in all combination treatments of larvae.Conclusion: The interaction between M. anispliae and spinosad indicated a synergetic effect that increased the house fly mortality as well as reduced the lethal time.

  19. Physico-chemical properties and fertility status of water eroded soils of Sharkul area of district Mansehra, Pakistan

    Directory of Open Access Journals (Sweden)

    Farmanullah Khan, A. Iqbal

    2011-11-01

    Full Text Available Soil degradation is the major threat to agricultural sustainability because it affects the soil productivity. Present study was conducted in 2008 to evaluate physico-chemical properties and fertility status of some eroded soil series of Sharkul area district Manshera, Hazara division, Khyber Pakhtunkhwa, Pakistan. Six soil series including slightly eroded (Dosera and Girari, moderately eroded (Nakholi and Sharkul and severely eroded (Ahl and Banser were selected. Soil samples were collected from surface (0-15 cm, subsurface (30-45 cm and substrata soil (60-75cm depths and were analyzed for various soil properties. Due to severity of erosion, bulk density increased, while total porosity, saturation percentage and organic matter decreased significantly. AB-DTPA extractable P, K, Fe, Cu, Zn, and Mn concentrations were decreased due to the severity of erosion in surface and sub surface soils, whereas in the substrata soils (60-75 cm depth, the effect of erosion was almost non significant. Sub-surface and sub-strata soils were found deficient in available P ( Zn > Fe > Mn. The physical and chemical properties of eroded soils varied significantly and the increasing severity of erosion resulted in corresponding deterioration of soil quality.

  20. Local and non-local effects of spanwise finite perturbations in erodible river bathymetries

    Science.gov (United States)

    Musa, Mirko; Hill, Craig; Guala, Michele

    2015-11-01

    Laboratory experiments were performed to study the effect of axial-flow hydrokinetic turbine models on an erodible river bed under live-bed conditions. Results indicate that the presence of an operating turbine rotor creates a blockage in the mean flow which produces a remarkable geomorphic signature in the migrating bedforms. These impacts affect a local area downstream of the turbines when placed symmetrically with respect to the cross section of the channel. On the other hand, more interesting results are observed with an asymmetric installation of the turbines. This configuration demonstrates a stronger effect on the mean flow, resulting in a larger plan-wise distortion of the mean topography and differential migration patterns of bedforms. Different turbine installation arrangements and hub heights above the mean bed were investigated, focusing mainly on the perturbation of sediment transport characteristics influenced by the turbine wake. Additional results with spanwise modulated submerged walls explore the possibility to control river topography harvesting this type of geomorphic destabilization.

  1. Elastic wave generated by granular impact on rough and erodible surfaces

    Science.gov (United States)

    Bachelet, Vincent; Mangeney, Anne; de Rosny, Julien; Toussaint, Renaud; Farin, Maxime

    2018-01-01

    The elastic waves generated by impactors hitting rough and erodible surfaces are studied. For this purpose, beads of variable materials, diameters, and velocities are dropped on (i) a smooth PMMA plate, (ii) stuck glass beads on the PMMA plate to create roughness, and (iii) the rough plate covered with layers of free particles to investigate erodible beds. The Hertz model validity to describe impacts on a smooth surface is confirmed. For rough and erodible surfaces, an empirical scaling law that relates the elastic energy to the radius Rb and normal velocity Vz of the impactor is deduced from experimental data. In addition, the radiated elastic energy is found to decrease exponentially with respect to the bed thickness. Lastly, we show that the variability of the elastic energy among shocks increases from some percents to 70% between smooth and erodible surfaces. This work is a first step to better quantify seismic emissions of rock impacts in natural environment, in particular on unconsolidated soils.

  2. Vertical transmission of sublethal granulovirus infection in the Indian meal moth, Plodia interpunctella.

    Science.gov (United States)

    Burden, J P; Griffiths, C M; Cory, J S; Smith, P; Sait, S M

    2002-03-01

    Knowledge of the mechanisms of pathogen persistence in relation to fluctuations in host density is crucial to our understanding of disease dynamics. In the case of insect baculoviruses, which are typically transmitted horizontally via a lifestage that can persist outside the host, a key issue that remains to be elucidated is whether the virus can also be transmitted vertically as a sublethal infection. We show that RNA transcripts for the Plodia interpunctella GV granulin gene are present in a high proportion of P. interpunctella insects that survive virus challenge. Granulin is a late-expressed gene that is only transcribed after viral genome replication, its presence thus strongly indicates that viral genome replication has occurred. Almost all insects surviving the virus challenge tested positive for viral RNA in the larval and pupal stage. However, this proportion declined in the emerging adults. Granulin mRNA was also detected in both the ovaries and testes, which may represent a putative mechanism by which reduced fecundity in sublethally affected hosts might be manifested. RNA transcripts were also detected in 60-80% of second-generation larvae that were derived from mating surviving adults, but there was no difference between the sexes, with both males and females capable of transmitting a sublethal infection to their offspring. The data indicate that low-level persistent infection, with at least limited gene expression, can occur in P. interpunctella following survival of a granulovirus challenge. We believe that this is the first demonstration of a persistent, sublethal infection by a baculovirus to be initiated by a sublethal virus dose. We hypothesize that the 'latent' baculovirus infections frequently referred to in the literature may also be low level persistent, sublethal infections resulting from survival from initial baculovirus exposure.

  3. Effects of chlorimuron ethyl on terrestrial and wetland plants: Levels of, and time to recovery following sublethal exposure

    International Nuclear Information System (INIS)

    Carpenter, David; Boutin, Céline; Allison, Jane E.

    2013-01-01

    Current pesticide registration guidelines call for short-term testing of plants; long-term effects on vegetative parts and reproduction remain untested. The aims of our study were to determine level of recovery and recovery times for plants exposed to the sulfonylurea herbicide chlorimuron ethyl using data collected from single species, dose–response greenhouse experiments. The nine terrestrial and eight wetland species tested showed variable levels of recovery and recovery timeframes. Many species (six terrestrial and five wetland) were vegetatively stunted at sublethal doses and were reproductively impaired. Full recovery did not occur at all doses and maximum recovery times varied from 3 to 15 weeks in this controlled environment. In a complex community, affected species may be displaced by tolerant species, through interspecific competition, before they fully recover. It is plausible that individual populations could be diminished or eliminated through reduced seedbank inputs (annuals and perennials) and asexual reproduction (perennials). - Highlights: ► Native terrestrial and wetland plants were used to assess the risks of herbicide drift. ► Vegetative and reproductive health endpoints were evaluated over time. ► Recovery rates were found to be both species and dose dependant. ► Reproductive recovery does not always equal vegetative recovery. ► Susceptible species may be displaced by resilient or resistant species. - Capsule: This study serves to bridge the gap between simplified short-term greenhouse tests and effects of herbicides on recovery of non-target plant species after sublethal exposures.

  4. Robotic removal of eroded vaginal mesh into the bladder.

    Science.gov (United States)

    Macedo, Francisco Igor B; O'Connor, Jeffrey; Mittal, Vijay K; Hurley, Patrick

    2013-11-01

    Vaginal mesh erosion into the bladder after midurethral sling procedure or cystocele repair is uncommon, with only a few cases having been reported in the literature. The ideal surgical management is still controversial. Current options for removal of eroded mesh include: endoscopic, transvaginal or abdominal (either open or laparoscopic) approaches. We, herein, present the first case of robotic removal of a large eroded vaginal mesh into the bladder and discuss potential benefits and limitations of the technique. © 2013 The Japanese Urological Association.

  5. [Spatiotemporal variation of typical red soil eroded landscape pattern: a case study in Changting County of Fujian Province].

    Science.gov (United States)

    Wu, Guo-sheng; Lin, Hui-hua; Zhu, He-jian; Sha, Jin-ming; Dai, Wen-yuan

    2011-07-01

    Based on the 1988, 2000, and 2007 remote sensing images of a typical red soil eroded region (Changting County, Fujian Province) and the digital elevation model (DEM), the eroded landscape types were worked out, and the changes of the eroded landscape pattern in the region from 1988 to 2007 were analyzed with the spatial mathematics model. In 1988-2007, different eroded landscape types in the region had the characteristics of inter-transfer, mainly manifested in the transfer from seriously eroded to lightly eroded types but still existed small amount of the transference from lightly eroded to seriously eroded types. Little change was observed in the controid of the eroded landscape. In the County, Hetian Town was all along the eroded center. During the study period, the landscape pattern index showed a tendency of low heterogeneity, low fragmentation, and high regularization at landscape level, but an overall improvement and expansion of lightly eroded and easy-to-tackle patches as well as the partial improvement and fragmentation of seriously eroded and difficult-to-tackle patches at patch level.

  6. Sublethal effects of tritium on aquatic systems. Ecological effects of lithium and beryllium on important aquatic organisms and associted communities. Teratogenic effects of low-level magnetic fields

    International Nuclear Information System (INIS)

    Strand, J.A.; Emery, R.M.

    1980-01-01

    Continuing studies of the sublethal effects of tritium on freshwater species emphasize the potential for genetic transmission of suppressed immune competence in offspring of parental rainbow trout (Salmo gairdneri) exposed to tritium (0, 0.04, 0.4, 40.0 rads) during embryogenesis. We plan to determine the relative biological effectiveness of tritium beta irradiation when compared to 60 Co gamma irradiation using the relatively radiosensitive immune process of rainbow trout. During FY 1979, we concluded genetic effects studies and prepared a manuscript for open literature publication summarizing FY 1977 and FY 1978 studies on the permanence of suppression of the primary immune response in rainbow trout sublethally irradiated during embryogenesis. We are also studying the potential effects of beryllium and lithium on aquatic systems. Because of mining and refining subsequent to the use of these metals in the construction of fusion reactors, increased levels of each are likely to be encountered in surface waters. Studies included an evaluation of potential toxicity of lithium on embryological life stages of rainbow trout and an assessment of fate and effects in artificial stream habitats. Levels of lithium necessary to cause an observed effect would have to be at least three orders of magnitude above observed background. Studies initiated in FY 1978 include evaluation of effects of low-level magnetic fields on embryologic development of rainbow trout. The objective of these studies to provide data useful in assessing potentially harmful effects of low-level magnetic fields encountered by attendant personnel working in the transport and hot cell areas of fusion reactors. This approach is less costly than using mammalian systems, provides large numbers of experimental organisms for meaningful statistical analysis and permits examination of potential latent effects in a representative vertebrate

  7. Immunocytoadherence and sublethal irradiation

    International Nuclear Information System (INIS)

    Beaumariage, M.L.; Hiesche, K.; Revesz, L.; Haot, J.

    1975-01-01

    In sublethally irradiated CBA mice, the relative and absolute numbers of spontaneous rosette forming cells against sheep erythrocytes are markedly decreased in bone marrow. The decrease of the absolute number of spontaneous RFC is also important in the spleen in spite of an increase of the RFC relative number above the normal values between the 8th and 12th day after irradiation. The graft of normal bone marrow cells immediately after irradiation or the shielding of a medullary area during irradiation promotes the recovery of the immunocytoadherence capacity of the bone marrow cells but not of the spleen cells [fr

  8. Textural characteristics and sedimentary environment of sediment at eroded and deposited regions in the severely eroded coastline of Batu Pahat, Malaysia.

    Science.gov (United States)

    Wan Mohtar, Wan Hanna Melini; Nawang, Siti Aminah Bassa; Abdul Maulud, Khairul Nizam; Benson, Yannie Anak; Azhary, Wan Ahmad Hafiz Wan Mohamed

    2017-11-15

    This study investigates the textural characteristics of sediments collected at eroded and deposited areas of highly severed eroded coastline of Batu Pahat, Malaysia. Samples were taken from systematically selected 23 locations along the 67km stretch of coastline and are extended to the fluvial sediments of the main river of Batu Pahat. Grain size distribution analysis was conducted to identify its textural characteristics and associated sedimentary transport behaviours. Sediments obtained along the coastline were fine-grained material with averaged mean size of 7.25 ϕ, poorly sorted, positively skewed and has wide distributions. Samples from eroded and deposition regions displayed no distinctive characteristics and exhibited similar profiles. The high energy condition transported the sediments as suspension, mostly as pelagic and the sediments were deposited as shallow marine and agitated deposits. The fluvial sediments of up to 3km into the river have particularly similar profile of textural characteristics with the neighbouring marine sediments from the river mouth. Profiles were similar with marine sediments about 3km opposite the main current and can go up to 10km along the current of Malacca Straits. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Lethal and sub-lethal effects of five pesticides used in rice farming on the earthworm Eisenia fetida

    NARCIS (Netherlands)

    Rico, Andreu; Sabater, Consuelo; Castillo, María Ángeles

    2016-01-01

    The toxicity of five pesticides typically used in rice farming (trichlorfon, dimethoate, carbendazim, tebuconazole and prochloraz) was evaluated on different lethal and sub-lethal endpoints of the earthworm Eisenia fetida. The evaluated endpoints included: avoidance behaviour after an exposure

  10. A Physically—Based Geometry Model for Transport Distance Estimation of Rainfall-Eroded Soil Sediment

    Directory of Open Access Journals (Sweden)

    Qian-Gui Zhang

    2016-01-01

    Full Text Available Estimations of rainfall-induced soil erosion are mostly derived from the weight of sediment measured in natural runoff. The transport distance of eroded soil is important for evaluating landscape evolution but is difficult to estimate, mainly because it cannot be linked directly to the eroded sediment weight. The volume of eroded soil is easier to calculate visually using popular imaging tools, which can aid in estimating the transport distance of eroded soil through geometry relationships. In this study, we present a straightforward geometry model to predict the maximum sediment transport distance incurred by rainfall events of various intensity and duration. In order to verify our geometry prediction model, a series of experiments are reported in the form of a sediment volume. The results show that cumulative rainfall has a linear relationship with the total volume of eroded soil. The geometry model can accurately estimate the maximum transport distance of eroded soil by cumulative rainfall, with a low root-mean-square error (4.7–4.8 and a strong linear correlation (0.74–0.86.

  11. Sub-lethal effects of pesticide residues in brood comb on worker honey bee (Apis mellifera development and longevity.

    Directory of Open Access Journals (Sweden)

    Judy Y Wu

    Full Text Available BACKGROUND: Numerous surveys reveal high levels of pesticide residue contamination in honey bee comb. We conducted studies to examine possible direct and indirect effects of pesticide exposure from contaminated brood comb on developing worker bees and adult worker lifespan. METHODOLOGY/PRINCIPAL FINDINGS: Worker bees were reared in brood comb containing high levels of known pesticide residues (treatment or in relatively uncontaminated brood comb (control. Delayed development was observed in bees reared in treatment combs containing high levels of pesticides particularly in the early stages (day 4 and 8 of worker bee development. Adult longevity was reduced by 4 days in bees exposed to pesticide residues in contaminated brood comb during development. Pesticide residue migration from comb containing high pesticide residues caused contamination of control comb after multiple brood cycles and provided insight on how quickly residues move through wax. Higher brood mortality and delayed adult emergence occurred after multiple brood cycles in contaminated control combs. In contrast, survivability increased in bees reared in treatment comb after multiple brood cycles when pesticide residues had been reduced in treatment combs due to residue migration into uncontaminated control combs, supporting comb replacement efforts. Chemical analysis after the experiment confirmed the migration of pesticide residues from treatment combs into previously uncontaminated control comb. CONCLUSIONS/SIGNIFICANCE: This study is the first to demonstrate sub-lethal effects on worker honey bees from pesticide residue exposure from contaminated brood comb. Sub-lethal effects, including delayed larval development and adult emergence or shortened adult longevity, can have indirect effects on the colony such as premature shifts in hive roles and foraging activity. In addition, longer development time for bees may provide a reproductive advantage for parasitic Varroa destructor

  12. Sublethal pesticide doses negatively affect survival and the cellular responses in American foulbrood-infected honeybee larvae

    Science.gov (United States)

    López, Javier Hernández; Krainer, Sophie; Engert, Antonia; Schuehly, Wolfgang; Riessberger-Gallé, Ulrike; Crailsheim, Karl

    2017-02-01

    Disclosing interactions between pesticides and bee infections is of most interest to understand challenges that pollinators are facing and to which extent bee health is compromised. Here, we address the individual and combined effect that three different pesticides (dimethoate, clothianidin and fluvalinate) and an American foulbrood (AFB) infection have on mortality and the cellular immune response of honeybee larvae. We demonstrate for the first time a synergistic interaction when larvae are exposed to sublethal doses of dimethoate or clothianidin in combination with Paenibacillus larvae, the causative agent of AFB. A significantly higher mortality than the expected sum of the effects of each individual stressor was observed in co-exposed larvae, which was in parallel with a drastic reduction of the total and differential hemocyte counts. Our results underline that characterizing the cellular response of larvae to individual and combined stressors allows unmasking previously undetected sublethal effects of pesticides in colony health.

  13. Sublethal Effects of Essential Oils From Eucalyptus staigeriana (Myrtales: Myrtaceae), Ocimum gratissimum (Lamiales: Laminaceae), and Foeniculum vulgare (Apiales: Apiaceae) on the Biology of Spodoptera frugiperda (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Cruz, G S; Wanderley-Teixeira, V; Oliveira, J V; Lopes, F S C; Barbosa, D R S; Breda, M O; Dutra, K A; Guedes, C A; Navarro, D M A F; Teixeira, A A C

    2016-04-01

    Spodoptera frugiperda (Smith 1797) (Lepidoptera: Noctuidae) is a major pest of maize, Zea mays L. Its control is often achieved through repeated applications per season of insecticides, which may lead to adverse effects on the ecosystem. Thus, the study of alternative methods with less environmental impact has expanded to include the use of essential oils. These oils are products of the secondary metabolism in plants, and their insecticidal activity has been widely demonstrated in populations of many pest insects. This study evaluated the insecticidal activities of essential oils from Eucalyptus staigeriana, Ocimum gratissimum, and Foeniculum vulgare on Spodoptera frugiperda. Gas chromatography–mass spectrometry profiles and contact toxicity of these oils as well as their sublethal effects on larvae and reproductive parameters in adults were evaluated. All three oils had sublethal effects on S. frugiperda; however, the oil of O. gratissimum showed the best results at all doses tested. These essential oils may have promise for control of S. frugiperda.

  14. Biodiversity of soil bacteria exposed to sub-lethal concentrations of phosphonium-based ionic liquids: Effects of toxicity and biodegradation

    DEFF Research Database (Denmark)

    Sydow, Mateusz; Owsianiak, Mikołaj; Framski, Grzegorz

    2018-01-01

    on the structure of microbial community present in an urban park soil in 100-day microcosm experiments. The biodiversity decreased in all samples (Shannon's index decreased from 1.75 down to 0.74 and OTU's number decreased from 1399 down to 965) with the largest decrease observed in the microcosms spiked with ILs...... ILs or their metabolites. Thus, the introduction of phosphonium-based ILs into soils at sub-lethal concentrations may result not only in a decrease in biodiversity due to toxic effects, but also in enrichment with ILs-degrading bacteria....

  15. Inductions of reproduction and population growth in the generalist predator Cyrtorhinus lividipennis (Hemiptera: Miridae) exposed to sub-lethal concentrations of insecticides.

    Science.gov (United States)

    Lu, Weiwei; Xu, Qiujing; Zhu, Jun; Liu, Chen; Ge, Linquan; Yang, Guoqing; Liu, Fang

    2017-08-01

    The miridbug, Cyrtorhinus lividipennis, is a significant predacious enemy of rice planthoppers. The effects of sub-lethal concentrations of triazophos, deltamethrin and imidacloprid on fecundity, egg hatchability, expression levels of genes associated with reproduction, and population growth in C. lividipennis were investigated. The fecundities for three pair combinations (♀ c × ♂ t , ♀ t × ♂ c and ♀ t × ♂ t ) treated with sub-lethal concentrations of the insecticides triazophos, deltamethrin and imidacloprid (LC 10 and LC 20 ) showed a significant increase compared to the untreated pairs (♀ c × ♂ c ). However, sub-lethal concentration treatments did not affect the egg hatchability. The ClVg expression levels of female adults exposed to triazophos, deltamethrin and imidacloprid (LC 20 ) increased by 52.6, 48.9 and 91.2%, respectively. The ClSPATA13 expression level of adult males exposed to triazophos, deltamethrim and imidacloprid (LC 20 ) increased by 80.7, 41.3 and 48.3%, respectively. Furthermore, sub-lethal concentrations of insecticides (LC 20 ) caused increased population numbers in C. lividipennis. Sub-lethal concentrations of triazophos, deltamethrin and imidacloprid stimulated reproduction and enhanced population growth of C. lividipennis. The reproductive stimulation might result from the up-regulation of ClVg or ClSPATA13. These findings may be useful in mediating populations of planthoppers. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  16. Fipronil promotes motor and behavioral changes in honey bees (Apis mellifera) and affects the development of colonies exposed to sublethal doses.

    Science.gov (United States)

    Zaluski, Rodrigo; Kadri, Samir Moura; Alonso, Diego Peres; Martins Ribolla, Paulo Eduardo; de Oliveira Orsi, Ricardo

    2015-05-01

    Bees play a crucial role in pollination and generate honey and other hive products; therefore, their worldwide decline is cause for concern. New broad-spectrum systemic insecticides such as fipronil can harm bees and their use has been discussed as a potential threat to bees' survival. In the present study, the authors evaluate the in vitro toxicity of fipronil and note behavioral and motor activity changes in Africanized adult Apis mellifera that ingest or come into contact with lethal or sublethal doses of fipronil. The effects of sublethal doses on brood viability, population growth, behavior, and the expression of the defensin 1 gene in adult bees were studied in colonies fed with contaminated sugar syrup (8 µg fipronil L(-1) ). Fipronil is highly toxic to bees triggering agitation, seizures, tremors, and paralysis. Bees that are exposed to a lethal or sublethal doses showed reduced motor activity. The number of eggs that hatched, the area occupied by worker eggs, and the number of larvae and pupae that developed were reduced, adult bees showed lethargy, and colonies were abandoned when they were exposed to sublethal doses of fipronil. No change was seen in the bees' expression of defensin 1. The authors conclude that fipronil is highly toxic to honey bees and even sublethal doses may negatively affect the development and maintenance of colonies. © 2015 SETAC.

  17. Strength, shrinkage, erodibility and capillary flow characteristics of cement-treated recycled pavement materials

    Directory of Open Access Journals (Sweden)

    William Fedrigo

    2017-09-01

    Full Text Available Full-depth recycling with portland cement (FDR-PC has been widely used for pavement rehabilitation; however, doubts remain regarding factors affecting some properties of the recycled material. Aiming on quantifying the effects of those factors on the strength, drying shrinkage, erodibility, capillary rise and absorption of cement-treated mixtures (CTM of reclaimed asphalt pavement (RAP and graded crushed stone, tests were conducted considering different RAP contents, cement contents, compaction efforts and curing times. Cement addition increased the mixtures strength and reduced their erodibility and capillary flow characteristics, but increased shrinkage. Low cement contents resulted in acceptable strength for CTM, but in high capillary rise and absorption, not being suitable if the layer is exposed to long periods of water soaking. Higher compaction effort led to similar effects as cement addition, counterbalancing low cement contents usage and reducing costs and shrinkage cracking risk. Strength and shrinkage showed higher growth rates at early stages, and then precautions should be taken in order to avoid moisture loss. Increasing RAP content decreased strength; though, RAP effect on the other properties was statistically non-significant, indicating a similar behaviour as CTM without RAP. Considering the studied properties, the mixture with most satisfactory behaviour for field applications was identified. The results highlighted strength is not the only property to be considered when designing FDR-PC mixtures; although presenting acceptable strength, some mixtures may fail due to shrinkage cracking or erosion, when exposed to water content variations. Keywords: Full-depth recycling with cement, Strength, Drying shrinkage, Erodibility, Capillary rise, Absorption

  18. Lethal and sublethal effects of methoxyphenozide on the development, survival and reproduction of the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

    International Nuclear Information System (INIS)

    Zarate, N.; Diaz, O.; Martinez, A.M.; Figueroa, J.I.; Pineda, S.; Schneider, M.I.; Smagghe, G.; Vinuela, E.; Budia, F.

    2011-01-01

    The lethal and sublethal effects of the ecdysone agonist methoxyphenozide on the fall armyworm, Spodoptera frugiperda (J. E. Smith), were investigated by feeding a methoxyphenozide-treated diet to fifth instars until pupation in doses corresponding to the LC 10 and LC 25 for the compound. Larval mortality reached 8% and 26% in the low and high concentration groups, respectively, on the seventh day of the experiment. A progressive larval mortality of 12% for the LC 10 and 60% for the LC 25 was observed before pupation. Treated larvae exhibited lower pupal weights, higher pupal mortality, presence of deformed pupae, and more deformed adults than untreated larvae. The incorporation of methoxyfenozide into the diet had a significant effect on the timing of larval development. The development period for males and females was about seven days longer than the controls for both concentrations tested. In contrast, the compound affected neither pupae nor adult longevity. Finally, S. frugiperda adults that resulted from fifth instars treated with methoxyfenozide were not affected in their mean cumulative number of eggs laid per female (fecundity), nor percentages of eggs hatched (fertility), or the sex ratio. Our results suggest that the combination of lethal and sublethal effects of methoxyfenozide may have important implications for the population dynamics of the fall armyworm. (author)

  19. Sublethal concentrations of ichthyotoxic alga Prymnesium parvum affect rainbow trout susceptibility to viral haemorrhagic septicaemia virus

    DEFF Research Database (Denmark)

    Andersen, Nikolaj Gedsted; Lorenzen, Ellen; Boutrup, Torsten Snogdal

    2016-01-01

    Ichthyotoxic algal blooms are normally considered a threat to maricultured fish only when blooms reach lethal cell concentrations. The degree to which sublethal algal concentrations challenge the health of the fish during blooms is practically unknown. In this study, we analysed whether sublethal...

  20. Advancing Understanding of Earthquakes by Drilling an Eroding Convergent Margin

    Science.gov (United States)

    von Huene, R.; Vannucchi, P.; Ranero, C. R.

    2010-12-01

    A program of IODP with great societal relevance is sampling and instrumenting the seismogenic zone. The zone generates great earthquakes that trigger tsunamis, and submarine slides thereby endangering coastal communities containing over sixty percent of the earth’s population. To asses and mitigate this endangerment it is urgent to advance understanding of fault dynamics that allows more timely anticipation of hazardous seismicity. Seismogenesis on accreting and eroding convergent plate boundaries apparently differ because of dissimilar materials along the interplate fault. As the history of instrumentally recorded earthquakes expands the difference becomes clearer. The more homogeneous clay, silt and sand subducted at accreting margins is associated with great earthquakes (M 9) whereas the fragmented upper plate rock that can dominate subducted material along an eroding margin plate interface is associated with many tsunamigenic earthquakes (Bilek, 2010). Few areas have been identified where the seismogenic zone can be reached with scientific drilling. In IODP accreting margins are studied on the NanTroSeize drill transect off Japan where the ultimate drilling of the seismogenic interface may occur by the end of IODP. The eroding Costa Rica margin will be studied in CRISP where a drill program will begin in 2011. The Costa Rican geophysical site survey will be complete with acquisition and processing of 3D seismic data in 2011 but the entire drilling will not be accomplished in IODP. It is appropriate that the accreting margin study be accomplished soon considering the indications of a pending great earthquake that will affect a country that has devoted enormous resources to IODP. However, understanding the erosional end-member is scientifically as important to an understanding of fault mechanics. Transoceanic tsunamis affect the entire Pacific rim where most subduction zones are eroding margins. The Costa Rican subduction zone is less complex operationally and

  1. Sublethal Growth Effects and Mortality to Marine Bivalves and Fish from Long-Term Exposure to Tributyltin.

    Science.gov (United States)

    1985-07-01

    sublethal toxicity of tributyltin oxide (TBTO) and its putative environmental product, tribu- tyltin sulfide ( TBTS ) to zoeal mud crabs, RIthropanopeus...Organotin .,’vwfuf coatingsu~~ study better defines the longterm toxicity and bloaccumnulation potential of tributyltin released from antifouting...larval fish survival at low tributyltin concentrations were also tested. Acute toxicity tests (96 hours) were con- ducted with mysid shrmp (Aawhomyot

  2. Use of various acute, sublethal and early life-stage tests to evaluate the toxicity of refinery effluents

    International Nuclear Information System (INIS)

    Sherry, J.; Scott, B.; Dutka, B.

    1997-01-01

    The toxicities of effluents from three Ontario, Canada, refineries were assessed with microbes, plants, invertebrates, and fish. Acute toxicity was assessed by the Microtox test, an assay based on electron transport activity in submitochondrial particles, and Daphnia magna (water flea); growth of Selenastrum capricornutum (alga); growth of Lemna minor (aquatic plant); germination of Lactuca sativa (nonaquatic plant); survival, growth, and maturation of Panagrellus redivivus (nematode); and genotoxicity in the SOS-Chromotest. Only the Microtox test and the submitochondrial particle test detected acute toxicity in the effluent samples. Reduced survival and sublethal responses were caused by some effluents, but not all effluents were toxic, and none caused a response in all of the tests applied. The results suggest that the effluent treatment systems used at Ontario refineries have largely eliminated acute toxicity to the organisms in their test battery. Although reduced survival and sublethal effects were detected in some of the effluents, the effects were minor. Some of the tests provided evidence, albeit weak, of variations in the responses of the test organisms to a temporal series of effluent samples. Not unexpectedly, there were also minor differences in the responses of the tests to effluents from the three refineries. The fathead minnow test seems to be a sensitive indicator of the sublethal toxicity of Ontario refinery effluents

  3. The sublethal effects of endosulfan on the circadian rhythms and locomotor activity of two sympatric parasitoid species.

    Science.gov (United States)

    Delpuech, Jean-Marie; Bussod, Sophie; Amar, Aurelien

    2015-08-01

    The organochlorine insecticide endosulfan is dispersed worldwide and significantly contributes to environmental pollution. It is an antagonist of the neurotransmitter gamma-aminobutyric acid (GABA), which is also indirectly involved in photoperiodic time measurement. In this study, we show that endosulfan at a dose as low as LC 0.1 modified the rhythm of locomotor activity of two sympatric parasitoid species, Leptopilina boulardi and Leptopilina heterotoma. The insecticide strongly increased the nocturnal activity of both species and synchronized their diurnal activity; these activities were not synchronized under control conditions. Parasitoids are important species in ecosystems because they control the populations of other insects. In this paper, we discuss the possible consequences of these sublethal effects and highlight the importance of such effects in evaluating the consequences of environmental pollution due to insecticides. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Sublethal Effects in Pest Management: A Surrogate Species Perspective on Fruit Fly Control

    Directory of Open Access Journals (Sweden)

    John E. Banks

    2017-07-01

    Full Text Available Tephritid fruit flies are economically important orchard pests globally. While much effort has focused on controlling individual species with a combination of pesticides and biological control, less attention has been paid to managing assemblages of species. Although several tephritid species may co-occur in orchards/cultivated areas, especially in mixed-cropping schemes, their responses to pesticides may be highly variable. Furthermore, predictive efforts about toxicant effects are generally based on acute toxicity, with little or no regard to long-term population effects. Using a simple matrix model parameterized with life history data, we quantified the responses of several tephritid species to the sublethal effects of a toxicant acting on fecundity. Using a critical threshold to determine levels of fecundity reduction below which species are driven to local extinction, we determined that threshold levels vary widely for the three tephritid species. In particular, Bactrocera dorsalis was the most robust of the three species, followed by Ceratitis capitata, and then B. cucurbitae, suggesting individual species responses should be taken into account when planning for area-wide pest control. The rank-order of susceptibility contrasts with results from several field/lab studies testing the same species, suggesting that considering a combination of life history traits and individual species susceptibility is necessary for understanding population responses of species assemblages to toxicant exposure.

  5. Lethal and sublethal effects of methoxyphenozide on the development, survival and reproduction of the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

    Energy Technology Data Exchange (ETDEWEB)

    Zarate, N.; Diaz, O. [Universidad Autonoma de San Luis Potosi (Mexico). Facultad de Agronomia; Martinez, A.M.; Figueroa, J.I.; Pineda, S., E-mail: spineda_us@yahoo.co [Universidad Michoacana de San Nicolas de Hidalgo, Tarimbaro, Michoacan (Mexico). Inst. de Investigaciones Agropecuarias y Forestales; Schneider, M.I. [National Council of Scientific and Technical Research (CEPAVE/CCT/CONICET), La Plata (Argentina). Centro de Estudios Parasitologicos y de Vectores. Centro Cientifico Tecnologico; Smagghe, G. [Ghent University, Ghent (Belgium). Faculty of Bioscience Engineering. Lab of Agrozoology; Vinuela, E.; Budia, F. [Escuela Tecnica Superior de Ingenieros Agronomos, Madrid (Spain). Escuela Tecnica Superior de Ingenieros Agronomos. Proteccion de Cultivos

    2011-01-15

    The lethal and sublethal effects of the ecdysone agonist methoxyphenozide on the fall armyworm, Spodoptera frugiperda (J. E. Smith), were investigated by feeding a methoxyphenozide-treated diet to fifth instars until pupation in doses corresponding to the LC{sub 10} and LC{sub 25} for the compound. Larval mortality reached 8% and 26% in the low and high concentration groups, respectively, on the seventh day of the experiment. A progressive larval mortality of 12% for the LC{sub 10} and 60% for the LC{sub 25} was observed before pupation. Treated larvae exhibited lower pupal weights, higher pupal mortality, presence of deformed pupae, and more deformed adults than untreated larvae. The incorporation of methoxyfenozide into the diet had a significant effect on the timing of larval development. The development period for males and females was about seven days longer than the controls for both concentrations tested. In contrast, the compound affected neither pupae nor adult longevity. Finally, S. frugiperda adults that resulted from fifth instars treated with methoxyfenozide were not affected in their mean cumulative number of eggs laid per female (fecundity), nor percentages of eggs hatched (fertility), or the sex ratio. Our results suggest that the combination of lethal and sublethal effects of methoxyfenozide may have important implications for the population dynamics of the fall armyworm. (author)

  6. A Locomotor Deficit Induced by Sublethal Doses of Pyrethroid and Neonicotinoid Insecticides in the Honeybee Apis mellifera.

    Science.gov (United States)

    Charreton, Mercédès; Decourtye, Axel; Henry, Mickaël; Rodet, Guy; Sandoz, Jean-Christophe; Charnet, Pierre; Collet, Claude

    2015-01-01

    The toxicity of pesticides used in agriculture towards non-targeted organisms and especially pollinators has recently drawn the attention from a broad scientific community. Increased honeybee mortality observed worldwide certainly contributes to this interest. The potential role of several neurotoxic insecticides in triggering or potentiating honeybee mortality was considered, in particular phenylpyrazoles and neonicotinoids, given that they are widely used and highly toxic for insects. Along with their ability to kill insects at lethal doses, they can compromise survival at sublethal doses by producing subtle deleterious effects. In this study, we compared the bee's locomotor ability, which is crucial for many tasks within the hive (e.g. cleaning brood cells, feeding larvae…), before and after an acute sublethal exposure to one insecticide belonging to the two insecticide classes, fipronil and thiamethoxam. Additionally, we examined the locomotor ability after exposure to pyrethroids, an older chemical insecticide class still widely used and known to be highly toxic to bees as well. Our study focused on young bees (day 1 after emergence) since (i) few studies are available on locomotion at this stage and (ii) in recent years, pesticides have been reported to accumulate in different hive matrices, where young bees undergo their early development. At sublethal doses (SLD48h, i.e. causing no mortality at 48 h), three pyrethroids, namely cypermethrin (2.5 ng/bee), tetramethrin (70 ng/bee), tau-fluvalinate (33 ng/bee) and the neonicotinoid thiamethoxam (3.8 ng/bee) caused a locomotor deficit in honeybees. While the SLD48h of fipronil (a phenylpyrazole, 0.5 ng/bee) had no measurable effect on locomotion, we observed high mortality several days after exposure, an effect that was not observed with the other insecticides. Although locomotor deficits observed in the sublethal range of pyrethroids and thiamethoxam would suggest deleterious effects in the field, the case of

  7. A Locomotor Deficit Induced by Sublethal Doses of Pyrethroid and Neonicotinoid Insecticides in the Honeybee Apis mellifera.

    Directory of Open Access Journals (Sweden)

    Mercédès Charreton

    Full Text Available The toxicity of pesticides used in agriculture towards non-targeted organisms and especially pollinators has recently drawn the attention from a broad scientific community. Increased honeybee mortality observed worldwide certainly contributes to this interest. The potential role of several neurotoxic insecticides in triggering or potentiating honeybee mortality was considered, in particular phenylpyrazoles and neonicotinoids, given that they are widely used and highly toxic for insects. Along with their ability to kill insects at lethal doses, they can compromise survival at sublethal doses by producing subtle deleterious effects. In this study, we compared the bee's locomotor ability, which is crucial for many tasks within the hive (e.g. cleaning brood cells, feeding larvae…, before and after an acute sublethal exposure to one insecticide belonging to the two insecticide classes, fipronil and thiamethoxam. Additionally, we examined the locomotor ability after exposure to pyrethroids, an older chemical insecticide class still widely used and known to be highly toxic to bees as well. Our study focused on young bees (day 1 after emergence since (i few studies are available on locomotion at this stage and (ii in recent years, pesticides have been reported to accumulate in different hive matrices, where young bees undergo their early development. At sublethal doses (SLD48h, i.e. causing no mortality at 48 h, three pyrethroids, namely cypermethrin (2.5 ng/bee, tetramethrin (70 ng/bee, tau-fluvalinate (33 ng/bee and the neonicotinoid thiamethoxam (3.8 ng/bee caused a locomotor deficit in honeybees. While the SLD48h of fipronil (a phenylpyrazole, 0.5 ng/bee had no measurable effect on locomotion, we observed high mortality several days after exposure, an effect that was not observed with the other insecticides. Although locomotor deficits observed in the sublethal range of pyrethroids and thiamethoxam would suggest deleterious effects in the field

  8. Effects of acute sublethal gamma radiation exposure on aggressive behavior in male mice: A dose-response study

    International Nuclear Information System (INIS)

    Maier, D.M.; Landauer, M.R.

    1989-01-01

    The resident-intruder paradigm was used to assess the effects of gamma radiation (0, 3, 5, 7 Gray [Gy] cobalt-60) on aggressive offensive behavior in resident male mice over a 3-month period. The defensive behavior of nonirradiated intruder mice was also monitored. A dose of 3 Gy had no effect on either the residents' offensive behavior or the defensive behavior of the intruders paired with them. Doses of 5 and 7 Gy produced decreases in offensive behavior of irradiated residents during the second week postirradiation. The nonirradiated intruders paired with these animals displayed decreases in defensive behavior during this time period, indicating a sensitivity to changes in the residents' behavior. After the third week postirradiation, offensive and defensive behavior did not differ significantly between irradiated mice and sham-irradiated controls. This study suggests that sublethal doses of radiation can temporarily suppress aggressive behavior but have no apparent permanent effect on that behavior

  9. Sublethal Effects of Neonicotinoid Insecticide on Calling Behavior and Pheromone Production of Tortricid Moths.

    Science.gov (United States)

    Navarro-Roldán, Miguel A; Gemeno, César

    2017-09-01

    In moths, sexual behavior combines female sex pheromone production and calling behavior. The normal functioning of these periodic events requires an intact nervous system. Neurotoxic insecticide residues in the agroecosystem could impact the normal functioning of pheromone communication through alteration of the nervous system. In this study we assess whether sublethal concentrations of the neonicotinoid insecticide thiacloprid, that competitively modulates nicotinic acetylcholine receptors at the dendrite, affect pheromone production and calling behavior in adults of three economically important tortricid moth pests; Cydia pomonella (L.), Grapholita molesta (Busck), and Lobesia botrana (Denis & Schiffermüller). Thiacloprid significantly reduced the amount of calling in C. pomonella females at LC 0.001 (a lethal concentration that kills only 1 in 10 5 individuals), and altered its calling period at LC 1 , and in both cases the effect was dose-dependent. In the other two species the effect was similar but started at higher LCs, and the effect was relatively small in L. botrana. Pheromone production was altered only in C. pomonella, with a reduction of the major compound, codlemone, and one minor component, starting at LC 10 . Since sex pheromones and neonicotinoids are used together in the management of these three species, our results could have implications regarding the interaction between these two pest control methods.

  10. Effect of exposure to sublethal concentrations of sodium cyanide on the carbohydrate metabolism of the Indian Major Carp Labeo rohita (Hamilton, 1822

    Directory of Open Access Journals (Sweden)

    Praveen N. Dube

    2013-07-01

    Full Text Available Experiments were designed to study in-vivo effects of sodium cyanide on biochemical endpoints in the freshwater fish Labeo rohita. Fish were exposed to two sublethal concentrations (0.106 and 0.064mg/L for a period of 15 days. Levels of glycogen, pyruvate, lactate and the enzymatic activities of lactate dehydrogenase (LDH, succinate dehydrogenase (SDH, glucose-6-phosphate dehydrogenase (G6PDH, phosphorylase, alkaline phosphatase (ALP, acid phosphatase (AcP were assessed in different tissues (liver, muscle and gills. Result indicated a steady decrease in glycogen, pyruvate, SDH, ALP and AcP activity with a concomitant increase in the lactate, phosphorylase, LDH and G6PD activity in all selected tissues. The alterations in all the above biochemical parameters were significantly (p<0.05 time and dose dependent. In all the above parameters, liver pointing out the intensity of cyanide intoxication compare to muscle and gills. Study revealed change in the metabolic energy by means of altered metabolic profile of the fish. Further, these observations indicated that even sublethal concentrations of sodium cyanide might not be fully devoid of deleterious influence on metabolism in L. rohita.

  11. Potential hepatic toxicity of buprofezin at sublethal concentrations: ROS-mediated conversion of energy metabolism.

    Science.gov (United States)

    Ji, Xiaotong; Ku, Tingting; Zhu, Na; Ning, Xia; Wei, Wei; Li, Guangke; Sang, Nan

    2016-12-15

    Buprofezin is known for its broad-spectrum action and environmental safety. The popularity of buprofezin has raised concerns about its potentially adverse effects on human health and risk to the environment. In this study, we first identified the liver as one of the major organs in which buprofezin accumulated, and we detected a severe oxidative stress response. Next, we demonstrated that sublethal concentrations of buprofezin promoted the conversion of energy metabolism from the aerobic tricarboxylic acid (TCA) cycle and oxidative phosphorylation to anaerobic glycolysis. Importantly, reactive oxygen species (ROS) generation partially accounted for the shunting of the energy metabolism through the buprofezin-mediated inhibition of cytochrome c oxidase activity. ROS directly perturbed the activities of several key TCA cycle enzymes, stimulated glycolysis, and indirectly disturbed the activity of the respiratory chain complex by altering mitochondrial DNA (mtDNA). These findings clarify the potential mechanisms of buprofezin toxicity and provide biomarkers for buprofezin-mediated hepatotoxicity at sublethal concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Influence of bleaching agents on surface roughness of sound or eroded dental enamel specimens.

    Science.gov (United States)

    Azrak, Birgül; Callaway, Angelika; Kurth, Petra; Willershausen, Brita

    2010-12-01

    The aim of the present in vitro study was to assess the effect of bleaching agents on eroded and sound enamel specimens. Enamel specimens prepared from human permanent anterior teeth were incubated with different bleaching agents containing active ingredients as 7.5 or 13.5% hydrogen peroxide or 35% carbamide peroxide, ranging in pH from 4.9 to 10.8. The effect of the tooth whitening agents on surface roughness was tested for sound enamel surfaces as well as for eroded enamel specimens. To provoke erosive damage, the enamel specimens were incubated for 10 hours with apple juice (pH = 3.4). Afterwards, pretreated and untreated dental slices were incubated with one of the bleaching agents for 10 hours. The surface roughness (R(a)) of all enamel specimens (N = 80) was measured using an optical profilometric device. A descriptive statistical analysis of the R(a) values was performed. The study demonstrated that exposure to an acidic bleaching agent (pH = 4.9) resulted in a higher surface roughness (p = 0.043) than treatment with a high peroxide concentration (pH = 6.15). If the enamel surface was previously exposed to erosive beverages, subsequent bleaching may enhance damage to the dental hard tissue. Bleaching agents with a high concentration of peroxide or an acidic pH can influence the surface roughness of sound or eroded enamel. © 2010, COPYRIGHT THE AUTHORS. JOURNAL COMPILATION © 2010, WILEY PERIODICALS, INC.

  13. Acute and sub-lethal response to mercury in Arctic and boreal calanoid copepods.

    Science.gov (United States)

    Overjordet, Ida Beathe; Altin, Dag; Berg, Torunn; Jenssen, Bjørn Munro; Gabrielsen, Geir Wing; Hansen, Bjørn Henrik

    2014-10-01

    Acute lethal toxicity, expressed as LC50 values, is a widely used parameter in risk assessment of chemicals, and has been proposed as a tool to assess differences in species sensitivities to chemicals between climatic regions. Arctic Calanus glacialis and boreal Calanus finmarchicus were exposed to mercury (Hg(2+)) under natural environmental conditions including sea temperatures of 2° and 10°C, respectively. Acute lethal toxicity (96 h LC50) and sub-lethal molecular response (GST expression; in this article gene expression is used as a synonym of gene transcription, although it is acknowledged that gene expression is also regulated, e.g., at translation and protein stability level) were studied. The acute lethal toxicity was monitored for 96 h using seven different Hg concentrations. The sub-lethal experiment was set up on the basis of nominal LC50 values for each species using concentrations equivalent to 50, 5 and 0.5% of their 96 h LC50 value. No significant differences were found in acute lethal toxicity between the two species. The sub-lethal molecular response revealed large differences both in response time and the fold induction of GST, where the Arctic species responded both faster and with higher mRNA levels of GST after 48 h exposure. Under the natural exposure conditions applied in the present study, the Arctic species C. glacialis may potentially be more susceptible to mercury exposure on the sub-lethal level. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Ethoxyresorufin-O-deethylase activity and fixed wavelength fluorescence detection of PAHs metabolites in bile in turbot (Scophthalmus maximus L.) exposed to a dispersed topped crude oil in a continuous flow system

    International Nuclear Information System (INIS)

    Camus, L.; Aas, E.; Borseth, J.F.

    1998-01-01

    Long term effects of sublethal concentrations of oil on the marine environment have become of general concern. Cytochrome P4501A activity (EROD) in liver and fixed wavelength fluorescence detection of PAHs metabolites (FF) have in this study been used as biomarkers for dispersed oil exposure on a long term period of juvenile turbot (Scophthalmus maximus L.). A Continuous Flow System was used to carry out the study. The fish were continuously exposed to 0.125, 0.5 or 2.0 mg litre -1 dispersed topped crude oil for 6, 15, 24h 4 and 21 days followed by a 9 day recovery period in clean seawater. No induction of the cytochrome P4501A was measured. A maximum level in bile metabolites (4- to 5-fold) was recorded after 24h of exposure revealing thereby a detoxification process, but a decline occurred from day 4 to day 21. This study demonstrated that FF detection of PAHs metabolites in bile could be a more sensitive biomarker than EROD activity in a long term exposure to sublethal concentration of oil. (author)

  15. Renal Impairment with Sublethal Tubular Cell Injury in a Chronic Liver Disease Mouse Model.

    Directory of Open Access Journals (Sweden)

    Tokiko Ishida

    Full Text Available The pathogenesis of renal impairment in chronic liver diseases (CLDs has been primarily studied in the advanced stages of hepatic injury. Meanwhile, the pathology of renal impairment in the early phase of CLDs is poorly understood, and animal models to elucidate its mechanisms are needed. Thus, we investigated whether an existing mouse model of CLD induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC shows renal impairment in the early phase. Renal injury markers, renal histology (including immunohistochemistry for tubular injury markers and transmission electron microscopy, autophagy, and oxidative stress were studied longitudinally in DDC- and standard diet-fed BALB/c mice. Slight but significant renal dysfunction was evident in DDC-fed mice from the early phase. Meanwhile, histological examinations of the kidneys with routine light microscopy did not show definitive morphological findings, and electron microscopic analyses were required to detect limited injuries such as loss of brush border microvilli and mitochondrial deformities. Limited injuries have been recently designated as sublethal tubular cell injury. As humans with renal impairment, either with or without CLD, often show almost normal tubules, sublethal injury has been of particular interest. In this study, the injuries were associated with mitochondrial aberrations and oxidative stress, a possible mechanism for sublethal injury. Intriguingly, two defense mechanisms were associated with this injury that prevent it from progressing to apparent cell death: autophagy and single-cell extrusion with regeneration. Furthermore, the renal impairment of this model progressed to chronic kidney disease with interstitial fibrosis after long-term DDC feeding. These findings indicated that DDC induces renal impairment with sublethal tubular cell injury from the early phase, leading to chronic kidney disease. Importantly, this CLD mouse model could be useful for studying the

  16. Gene expression in Listeria monocytogenes exposed to sublethal concentration of benzalkonium chloride.

    Science.gov (United States)

    Tamburro, Manuela; Ripabelli, Giancarlo; Vitullo, Monia; Dallman, Timothy James; Pontello, Mirella; Amar, Corinne Francoise Laurence; Sammarco, Michela Lucia

    2015-06-01

    In this study, tolerance at sublethal concentration of benzalkonium chloride and transcription levels of mdrL, ladR, lde, sigB and bcrABC genes in Listeria monocytogenes strains were evaluated. Viable cells reduction occurred in 45% of strains and clinical isolates showed lower sensitivity than isolates from foods. An increased transcription of an efflux system encoding gene was found in 60% of strains, and simultaneous mdrL overexpression and ladR underexpression occurred in 30% of isolates. A significant association between reduced benzalkonium chloride activity and both mdrL and sigB overexpression was observed; sigB expression also correlated with both mdrL and ladR genes. The bcrABC gene was only found in six strains, all isolated from foods and sensitive to benzalkonium chloride, and in four strains an underexpression was observed. Disinfection at sublethal concentration was less effective in clinical isolates, and mdrL and sigB expression was significantly affected by disinfection. Further insights are needed to understand the adaptation to benzalkonium chloride and to evaluate whether changes in gene expression could affect the L. monocytogenes virulence traits and persistence in the environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Does selective logging stress tropical forest invertebrates? Using fat stores to examine sublethal responses in dung beetles.

    Science.gov (United States)

    França, Filipe; Barlow, Jos; Araújo, Bárbara; Louzada, Julio

    2016-12-01

    The increased global demand for tropical timber has driven vast expanses of tropical forests to be selectively logged worldwide. While logging impacts on wildlife are predicted to change species distribution and abundance, the underlying physiological responses are poorly understood. Although there is a growing consensus that selective logging impacts on natural populations start with individual stress-induced sublethal responses, this literature is dominated by investigations conducted with vertebrates from temperate zones. Moreover, the sublethal effects of human-induced forest disturbance on tropical invertebrates have never been examined. To help address this knowledge gap, we examined the body fat content and relative abundance of three dung beetle species (Coleoptera: Scarabaeinae) with minimum abundance of 40 individuals within each examined treatment level. These were sampled across 34 plots in a before-after control-impact design (BACI) in a timber concession area of the Brazilian Amazon. For the first time, we present evidence of logging-induced physiological stress responses in tropical invertebrates. Selective logging increased the individual levels of fat storage and reduced the relative abundance of two dung beetle species. Given this qualitative similarity, we support the measurement of body fat content as reliable biomarker to assess stress-induced sublethal effects on dung beetles. Understanding how environmental modification impacts the wildlife has never been more important. Our novel approach provides new insights into the mechanisms through which forest disturbances impose population-level impacts on tropical invertebrates.

  18. Contact Irritant Responses of Aedes aegypti Using Sublethal Concentration and Focal Application of Pyrethroid Chemicals

    OpenAIRE

    Manda, Hortance; Shah, Pankhil; Polsomboon, Suppaluck; Chareonviriyaphap, Theeraphap; Castro-Llanos, Fanny; Morrison, Amy; Burrus, Roxanne G.; Grieco, John P.; Achee, Nicole L.

    2013-01-01

    BACKGROUND: Previous studies have demonstrated contact irritant and spatial repellent behaviors in Aedes aegypti following exposure to sublethal concentrations of chemicals. These sublethal actions are currently being evaluated in the development of a push-pull strategy for Ae. aegypti control. This study reports on mosquito escape responses after exposure to candidate chemicals for a contact irritant focused push-pull strategy using varying concentrations and focal application. METHODS: Cont...

  19. Induction of specific Escherichia coli genes by sublethal treatments with alkylating agents.

    OpenAIRE

    Volkert, M R; Nguyen, D C

    1984-01-01

    Fusions of the lac operon to genes induced by treatment with sublethal levels of alkylating agents have been selected from random insertions of the Mu-dl(ApRlac) phage by screening for induction of beta-galactosidase activity in the presence of methyl methanesulfonate. Genetic analysis reveals that these fusions resulted from insertion of Mu-dl(ApRlac) into two regions of the chromosome. One region (aidA) is near his and, based on phenotypic effects, appears to represent insertion into the al...

  20. Sub-lethal effects of the neurotoxic pyrethroid insecticide Fastac 50EC on the general motor and locomotor activities of the non-targeted beneficial carabid beetle Platynus assimilis (Coleoptera: Carabidae).

    Science.gov (United States)

    Tooming, Ene; Merivee, Enno; Must, Anne; Sibul, Ivar; Williams, Ingrid

    2014-06-01

    Sub-lethal effects of pesticides on behavioural endpoints are poorly studied in carabids (Coleoptera: Carabidae) though changes in behaviour caused by chemical stress may affect populations of these non-targeted beneficial insects. General motor activity and locomotion are inherent in many behavioural patterns, and changes in these activities that result from xenobiotic influence mirror an integrated response of the insect to pesticides. Influence of pyrethroid insecticides over a wide range of sub-lethal doses on the motor activities of carabids still remains unclear. Video tracking of Platynus assimilis showed that brief exposure to alpha-cypermethrin at sub-lethal concentrations ranged from 0.01 to 100 mg L(-1) caused initial short-term (24 h) locomotor hypo-activity. In addition, significant short- and long-term concentration and time-dependent changes occurred in general motor activity patterns and rates. Conspicuous changes in motor activity of Platynus assimilis beetles treated at alpha-cypermethrin concentrations up to 75,000-fold lower than maximum field recommended concentration (MFRC) suggest that many, basic fitness-related behaviours might be severely injured as well. These changes may negatively affect carabid populations in agro-ecosystems. Long-term hypo-activity could directly contribute to decreased trap captures of carabids frequently observed after insecticide application in the field. © 2013 Society of Chemical Industry.

  1. Gene expression changes in honey bees induced by sublethal imidacloprid exposure during the larval stage.

    Science.gov (United States)

    Wu, Ming-Cheng; Chang, Yu-Wen; Lu, Kuang-Hui; Yang, En-Cheng

    2017-09-01

    Honey bee larvae exposed to sublethal doses of imidacloprid show behavioural abnormalities as adult insects. Previous studies have demonstrated that this phenomenon originates from abnormal neural development in response to imidacloprid exposure. Here, we further investigated the global gene expression changes in the heads of newly emerged adults and observed that 578 genes showed more than 2-fold changes in gene expression after imidacloprid exposure. This information might aid in understanding the effects of pesticides on the health of pollinators. For example, the genes encoding major royal jelly proteins (MRJPs), a group of multifunctional proteins with significant roles in the sustainable development of bee colonies, were strongly downregulated. These downregulation patterns were further confirmed through analyses using quantitative reverse transcription-polymerase chain reaction on the heads of 6-day-old nurse bees. To our knowledge, this study is the first to demonstrate that sublethal doses of imidacloprid affect mrjp expression and likely weaken bee colonies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Wind-eroded silicate as a source of hydrogen peroxide on Mars

    DEFF Research Database (Denmark)

    Bak, Ebbe Norskov; Merrison, Jonathan P.; Jensen, Svend Knak

    -sists of silicates [4] that due to wind erosion has a very fine grained texture. Based on the composition of the surface material and investigations showing that crushing of silicates can give rise to reactive oxygen species [5], we hypothesized that wind erosion of silicates can explain the reactivity of Martian...... soil. Wind-erosion of silicate could thus be one of several causes of the soil’s reactivity. As our experiments show, the globally distributed wind eroded silicate dust can lead to the production of hydrogen peroxide which might explain the reactivity of the Martian soil. The reactivity of eroded...

  3. MAPPING ERODED AREAS ON MOUNTAIN GRASSLAND WITH TERRESTRIAL PHOTOGRAMMETRY AND OBJECT-BASED IMAGE ANALYSIS

    Directory of Open Access Journals (Sweden)

    A. Mayr

    2016-06-01

    Full Text Available In the Alps as well as in other mountain regions steep grassland is frequently affected by shallow erosion. Often small landslides or snow movements displace the vegetation together with soil and/or unconsolidated material. This results in bare earth surface patches within the grass covered slope. Close-range and remote sensing techniques are promising for both mapping and monitoring these eroded areas. This is essential for a better geomorphological process understanding, to assess past and recent developments, and to plan mitigation measures. Recent developments in image matching techniques make it feasible to produce high resolution orthophotos and digital elevation models from terrestrial oblique images. In this paper we propose to delineate the boundary of eroded areas for selected scenes of a study area, using close-range photogrammetric data. Striving for an efficient, objective and reproducible workflow for this task, we developed an approach for automated classification of the scenes into the classes grass and eroded. We propose an object-based image analysis (OBIA workflow which consists of image segmentation and automated threshold selection for classification using the Excess Green Vegetation Index (ExG. The automated workflow is tested with ten different scenes. Compared to a manual classification, grass and eroded areas are classified with an overall accuracy between 90.7% and 95.5%, depending on the scene. The methods proved to be insensitive to differences in illumination of the scenes and greenness of the grass. The proposed workflow reduces user interaction and is transferable to other study areas. We conclude that close-range photogrammetry is a valuable low-cost tool for mapping this type of eroded areas in the field with a high level of detail and quality. In future, the output will be used as ground truth for an area-wide mapping of eroded areas in coarser resolution aerial orthophotos acquired at the same time.

  4. Effects of sublethal concentrations of bifenthrin and deltamethrin on fecundity, growth, and development of the honeybee Apis mellifera ligustica.

    Science.gov (United States)

    Dai, Ping-Li; Wang, Qiang; Sun, Ji-Hu; Liu, Feng; Wang, Xing; Wu, Yan-Yan; Zhou, Ting

    2010-03-01

    Bifenthrin and deltamethrin have been widely used as pesticides in agriculture and forestry and are becoming an increasing risk to honeybees. The honeybee, Apis mellifera ligustica, is widely recognized as a beneficial insect of agronomic, ecological, and scientific importance. It is important to understand what effects these chemicals have on bees. Effects of two pesticides at sublethal concentrations on fecundity, growth, and development of honeybees were examined with the feeding method for a three-year period (2006-2008). It was shown that both bifenthrin and deltamethrin significantly reduced bee fecundity, decreased the rate at which bees develop to adulthood, and increased their immature periods. The toxicity of bifenthrin and deltamethrin on workers of Apis mellifera ligustica was also assessed, and the results from the present study showed that the median lethal effects of bifenthrin and deltamethrin were 16.7 and 62.8 mg/L, respectively.

  5. Lethal and sublethal effects of cantharidin on the life history traits and population parameters of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Khan, Rashid A; Rashid, Maryam; Wang, Dun; Zhang, Ya-Lin

    2014-01-01

    The cotton bollworm, Helicoverpa armigera (Hübner), is a serious and cosmopolitan pest of many economic crops. Its control has not been adequate owing to its resistance to many groups of insecticides. Toxicity of cantharidin on armyworm and diamondback moth has already been reported. However, its toxicity on H. armigera has not been investigated previously. In this study, lethal and sublethal effects of cantharidin on H. armigera under laboratory conditions are reported. Results showed gross abnormalities in the population parameters of H. armigera, ranging from larvae to adults. Reduction in larval weight and wing malformation were observed in the cantharidin-treated population cohort, and higher mortality at the larval, pupal and adult stages was observed in cantharidin-treated H. armigera compared with the control. Moreover, almost 5 times less fecundity was recorded in the treated population cohort. Fertility was also severely affected, and reduction in all population parameters was observed. Cantharidin caused larval mortality and other serious abnormalities in H. armigera population parameters, and therefore may have positive implications for pest management decision-making process. More interestingly, the experiment revealed that cantharidin in sublethal dose mimicked insect growth regulator insecticides. Furthermore, cantharidin could be used as a precursor compound for the synthesis of new analogues and compounds to replace ineffective older compounds. © 2013 Society of Chemical Industry.

  6. Measurement of oxygen enhancement ratio for sub-lethal region using saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Nairy, Rajesha K.; Anjaria, K.B.; Bhat, Nagesh N.; Chaurasia, Rajesh K.; Balakrishnan, Sreedevi; Yerol, Narayana

    2013-01-01

    Oxygen is one of the best known modifiers of radiation sensitivity and the biological effects is greater in the presence of oxygen, and significant modifying effect will be observed only for low LET radiations. The reduced oxygen availability is sensed which trigger homeostatic responses, which impact on virtually all areas of biology and medicine. Failure to achieve complete response following radiotherapy of large tumors is attributed to the presence of radio-resistant hypoxic cells, therefore clarifying the mechanism of the oxygen effect is important. In the present study, a mutant type diploid yeast strain, Saccharomyces cerevisiae D7 was used to study Oxygen Enhancement Ratio (OER) using 60 Co gamma radiation. Cells were washed thrice by centrifugation (2000 g for 5 min) and re-suspended to a cell concentration of 1x108 cells mL-1 in a sterile polypropylene vial for irradiation (sub-lethal dose range, 0-100 Gy). Hypoxic conditions were achieved by incubating the cells in airtight vials at 30℃ for 30 min prior to irradiation. The gene conversion and back mutation analysis were carried out according to the standard protocol. Gene conversion is the radio-sensitive biological endpoint, that can be studied in Saccharomyces cerevisiae D7 yeast cells at trp locus in tryptophan (Trp- medium) deficient medium. The dose response relation at euoxic and hypoxic condition in sub-lethal doses are found to be linear and is represented by Y (Euoxic) = (6.54±0.102) D with R2=0.999 and for hypoxic condition Y(Hypoxic) = (3.346±0.033) D with R2=0.996. The OER can be calculated by dividing the euoxic slope with hypoxic slope, and is 1.95. Back mutation, which is a result of reversion of Isoleucine auxotrophs to prototrophs gives very good information at sub-lethal doses. The dose response relation between back mutated cells and radiation doses at Euoxic and hypoxic condition can be represented as Y(Euoxic) = (2.85±0.126) D with R2= 0.976 and for hypoxic condition Y

  7. Development of Cardiovascular and Neurodevelopmental Metrics as Sublethal Endpoints for the Fish Embryo Toxicity Test.

    Science.gov (United States)

    Krzykwa, Julie C; Olivas, Alexis; Jeffries, Marlo K Sellin

    2018-06-19

    The fathead minnow fish embryo toxicity (FET) test has been proposed as a more humane alternative to current toxicity testing methods, as younger organisms are thought to experience less distress during toxicant exposure. However, the FET test protocol does not include endpoints that allow for the prediction of sublethal adverse outcomes, limiting its utility relative to other test types. Researchers have proposed the development of sublethal endpoints for the FET test to increase its utility. The present study 1) developed methods for previously unmeasured sublethal metrics in fathead minnows (i.e., spontaneous contraction frequency and heart rate) and 2) investigated the responsiveness of several sublethal endpoints related to growth (wet weight, length, and growth-related gene expression), neurodevelopment (spontaneous contraction frequency, and neurodevelopmental gene expression), and cardiovascular function and development (pericardial area, eye size and cardiovascular related gene expression) as additional FET test metrics using the model toxicant 3,4-dichloroaniline. Of the growth, neurological and cardiovascular endpoints measured, length, eye size and pericardial area were found to more responsive than the other endpoints, respectively. Future studies linking alterations in these endpoints to longer-term adverse impacts are needed to fully evaluate the predictive power of these metrics in chemical and whole effluent toxicity testing. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  8. Critical analysis of the maximum non inhibitory concentration (MNIC) method in quantifying sub-lethal injury in Saccharomyces cerevisiae cells exposed to either thermal or pulsed electric field treatments.

    Science.gov (United States)

    Kethireddy, V; Oey, I; Jowett, Tim; Bremer, P

    2016-09-16

    Sub-lethal injury within a microbial population, due to processing treatments or environmental stress, is often assessed as the difference in the number of cells recovered on non-selective media compared to numbers recovered on a "selective media" containing a predetermined maximum non-inhibitory concentration (MNIC) of a selective agent. However, as knowledge of cell metabolic response to injury, population diversity and dynamics increased, the rationale behind the conventional approach of quantifying sub-lethal injury must be scrutinized further. This study reassessed the methodology used to quantify sub-lethal injury for Saccharomyces cerevisiae cells (≈ 4.75 Log CFU/mL) exposed to either a mild thermal (45°C for 0, 10 and 20min) or a mild pulsed electric field treatment (field strengths of 8.0-9.0kV/cm and energy levels of 8, 14 and 21kJ/kg). Treated cells were plated onto either Yeast Malt agar (YM) or YM containing NaCl, as a selective agent at 5-15% in 1% increments. The impact of sub-lethal stress due to initial processing, the stress due to selective agents in the plating media, and the subsequent variation of inhibition following the treatments was assessed based on the CFU count (cell numbers). ANOVA and a generalised least squares model indicated significant effects of media, treatments, and their interaction effects (P<0.05) on cell numbers. It was shown that the concentration of the selective agent used dictated the extent of sub-lethal injury recorded owing to the interaction effects of the selective component (NaCl) in the recovery media. Our findings highlight a potential common misunderstanding on how culture conditions impact on sub-lethal injury. Interestingly for S. cerevisiae cells the number of cells recovered at different NaCl concentrations in the media appears to provide valuable information about the mode of injury, the comparative efficacy of different processing regimes and the inherent degree of resistance within a population. This

  9. Lethal and sublethal effects of glyphosate (roundup active) to embryos of colombian anurans

    International Nuclear Information System (INIS)

    Triana Velasquez, Teofila Maria; Montes Rojas, Claudia; Bernal Bautista, Manuel Hernando

    2013-01-01

    Glyphosate is an herbicide widely used in agriculture, which may affect non-target species. the aim of this study was to determine the lethal (median lethal concentration - LC 5 0) and sublethal effects (changes on body size and development) of glyphosate (roundup active) to embryos of four anuran species, exposed during 96 hours under laboratory and microcosm tests. under laboratory conditions, engystomops pustulosus was the most tolerant species (LC 5 0 = 3033,18 ?g a.e./L) and rhinella marina was the most sensitive (lc50 = 1421,46 ?g a.e./L), which also showed a delayed development and significantly reduced body size. The other species had an intermediate LC50 (Rhinella humboldti = 2899.54 ?g a.e./L; hypsiboas crepitans = 2151,88 ?g a.e./L). In all cases, the laboratory LC 5 0 was lower than the concentration used in field (5392.92 ?g a.e./L), indicating a high toxic effect. In the microcosm tests, embryos of e. pustulosus were the most tolerant (LC 5 0 = 19,41 kg a.e./ha), while R. humboldti were the most sensitive (LC 5 0 = 10,61 kg a.e./ha). In this case, all four study species had a higher LC 5 0 than the concentration sprayed in field (3,69 kg a.e./ ha), so a lower lethal effect, and there were no significant differences in body size and development. This result shows that the glyphosate, as the commercial presentation roundup active, produce a moderate mortality on anuran embryos.

  10. Water and dissolved carbon transport in an eroding soil landscape using column experiments

    DEFF Research Database (Denmark)

    Rieckh, Helene; Gerke, Horst; Glæsner, Nadia

    2014-01-01

    In the hummocky ground moraine soil landscape, a spatial continuum of more or less eroded soils developed from till under intensive agricultural cultivation. Water flow and solute transport are affected by the variable soil structural and pedological developments, which are posing a challenge...... for flux estimation. The objective of this study was to investigate transport of water, dissolved organic (DOC), and particulate carbon (PC) through soil profiles of an eroded Haplic Luvisol and a heavily eroded Haplic Regosol. We studied 5 soil horizons in three replicates each: Ap (0-20 cm) and E (20...... boundary. Breakthrough curves for a pre-applied tracer (Br-) on the soil surface and a tracer applied with irrigation water (3H2O) were modeled analytically using CXTFIT. The heterogeneity of the Luvisol horizons was generally higher than that of the Regosol horizons, which relates to the higher...

  11. Eroded dentin does not jeopardize the bond strength of adhesive restorative materials

    Directory of Open Access Journals (Sweden)

    Janaina Barros Cruz

    2012-08-01

    Full Text Available This in vitro study evaluated the bond strength of adhesive restorative materials to sound and eroded dentin. Thirty-six bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated in 2 groups: sound dentin (immersion in artificial saliva and eroded dentin (pH cycling model - 3× / cola drink for 7 days. Specimens were then reassigned according to restorative material: glass ionomer cement (KetacTM Molar Easy Mix, resin-modified glass ionomer cement (VitremerTM or adhesive system with resin composite (Adper Single Bond 2 + Filtek Z250. Polyethylene tubes with an internal diameter of 0.76 mm were placed over the dentin and filled with the material. The microshear bond test was performed after 24 h of water storage at 37ºC. The failure mode was evaluated using a stereomicroscope (400×. Bond strength data were analyzed with two-way ANOVA and Tukey's post hoc tests (α = 0.05. Eroded dentin showed bond strength values similar to those for sound dentin for all materials. The adhesive system showed the highest bond strength values, regardless of the substrate (p < 0.0001. For all groups, the adhesive/mixed failure prevailed. In conclusion, adhesive materials may be used in eroded dentin without jeopardizing the bonding quality. It is preferable to use an etch-and-rinse adhesive system because it shows the highest bond strength values compared with the glass ionomer cements tested.

  12. Sub-Lethal Dose of Shiga toxin 2 from Enterohemorrhagic Escherichia coli Affects Balance and Cerebellar Cythoarquitecture.

    Directory of Open Access Journals (Sweden)

    Luciana eD’Alessio

    2016-02-01

    Full Text Available Shiga toxin producing Escherichia coli may damage the central nervous system before or concomitantly to manifested hemolytic uremic syndrome symptoms. The cerebellum is frequently damaged during this syndrome, however the deleterious effects of Shiga toxin 2 has never been integrally reported by ultrastructural, physiological and behavioral means. The aim of this study was to determine the cerebellar compromise after intravenous administration of a sub-lethal dose of Shiga toxin 2 by measuring the cerebellar blood brain barrier permeability, behavioral task of cerebellar functionality (inclined plane test, and ultrastructural analysis (transmission electron microscope. Intravenous administration of vehicle (control group, sub-lethal dose of 0.5 ηg and 1 ηg of Stx2 per mouse were tested for behavioral and ultrastructural studies. A set of three independent experiments were performed for each study (n=6. Blood–Brain Barrier resulted damaged and consequently its permeability was significantly increased. Lower scores obtained in the inclined plane task denoted poor cerebellar functionality in comparison to their controls. The most significant lower score was obtained after 5 days of 1ηg of toxin administration. Transmission electron microscope micrographs from the Stx2-treated groups showed neurons with a progressive neurodegenerative condition in a dose dependent manner. As sub-lethal intravenous Shiga toxin 2 altered the blood brain barrier permeability in the cerebellum the toxin penetrated the cerebellar parenchyma and produced cell damaged with significant functional implications in the test balance.

  13. Exposure to Sublethal Doses of Fipronil and Thiacloprid Highly Increases Mortality of Honeybees Previously Infected by Nosema ceranae

    Science.gov (United States)

    Vidau, Cyril; Diogon, Marie; Aufauvre, Julie; Fontbonne, Régis; Viguès, Bernard; Brunet, Jean-Luc; Texier, Catherine; Biron, David G.; Blot, Nicolas; El Alaoui, Hicham; Belzunces, Luc P.; Delbac, Frédéric

    2011-01-01

    Background The honeybee, Apis mellifera, is undergoing a worldwide decline whose origin is still in debate. Studies performed for twenty years suggest that this decline may involve both infectious diseases and exposure to pesticides. Joint action of pathogens and chemicals are known to threaten several organisms but the combined effects of these stressors were poorly investigated in honeybees. Our study was designed to explore the effect of Nosema ceranae infection on honeybee sensitivity to sublethal doses of the insecticides fipronil and thiacloprid. Methodology/Finding Five days after their emergence, honeybees were divided in 6 experimental groups: (i) uninfected controls, (ii) infected with N. ceranae, (iii) uninfected and exposed to fipronil, (iv) uninfected and exposed to thiacloprid, (v) infected with N. ceranae and exposed 10 days post-infection (p.i.) to fipronil, and (vi) infected with N. ceranae and exposed 10 days p.i. to thiacloprid. Honeybee mortality and insecticide consumption were analyzed daily and the intestinal spore content was evaluated 20 days after infection. A significant increase in honeybee mortality was observed when N. ceranae-infected honeybees were exposed to sublethal doses of insecticides. Surprisingly, exposures to fipronil and thiacloprid had opposite effects on microsporidian spore production. Analysis of the honeybee detoxification system 10 days p.i. showed that N. ceranae infection induced an increase in glutathione-S-transferase activity in midgut and fat body but not in 7-ethoxycoumarin-O-deethylase activity. Conclusions/Significance After exposure to sublethal doses of fipronil or thiacloprid a higher mortality was observed in N. ceranae-infected honeybees than in uninfected ones. The synergistic effect of N. ceranae and insecticide on honeybee mortality, however, did not appear strongly linked to a decrease of the insect detoxification system. These data support the hypothesis that the combination of the increasing

  14. Lethal and sublethal effects of marine sediment extracts on fish cells and chromosomes

    Science.gov (United States)

    Landolt, Marsha L.; Kocan, Richard M.

    1984-03-01

    The cost of conducting conventional chronic bioassays with every potentially toxic compound found in marine ecosystems is prohibitive; therefore short-term toxicity tests which can be used for rapid screening were developed. The tests employ cultured fish cells to measure lethal, sublethal or genotoxic effects of pure compounds and complex mixtures. The sensitivity of these tests has been proven under laboratory conditions; the following study used two of these tests, the anaphase aberration test and a cytotoxicity assay, under field conditions. Sediment was collected from 97 stations within Puget Sound, Washington. Serial washings of the sediment in methanol and dichloromethane yielded an organic extract which was dried, dissolved in DMSO and incubated as a series of dilutions with rainbow trout gonad (RTG-2) cells. The toxic effects of the extract were measured by examining the rate of cell proliferation and the percentage of damaged anaphase figures. Anaphase figures were considered to be abnormal if they exhibited non-disjunctions, chromosome fragments, or chromosome bridges. A second cell line (bluegill fry, BF-2) was also tested for cell proliferation and was included because, unlike the RTG-2 cell line, it contains little or no mixed function oxygenase activity. Of 97 stations tested, 35 showed no genotoxic activity, 42 showed high genotoxic activity (P≤.01) and the remainder were intermediate. Among the toxic sites were several deep water stations adjacent to municipal sewage outfalls and four urban waterways contaminated by industrial and municipal effluents. Extracts from areas that showed genotoxic effects also inhibited cell proliferation and were cytotoxic to RTG-2 cells. Few effects were noted in the MFO deficient BF-2 cells. Short term in vitro tests provide aquatic toxicologists with a versatile and cost effective tool for screening complex environments. Through these tests one can identify compounds or geographic regions that exhibit high

  15. Interrill and rill erodibility in the northern andean highlands

    NARCIS (Netherlands)

    Romero, C.; Stroosnijder, L.; Baigorria, G.A.

    2007-01-01

    There is a lack of quantitative information describing the physical processes causing soil erosion in the Andean Highlands, especially those related to interrill and rill erodibility factors. To assess how susceptible are soils to erosion in this region, field measurements of interrill (Ki) and rill

  16. Assessment of Chronic Sublethal Effects of Imidacloprid on Honey Bee Colony Health

    Science.gov (United States)

    Dively, Galen P.; Embrey, Michael S.; Kamel, Alaa; Hawthorne, David J.; Pettis, Jeffery S.

    2015-01-01

    Here we present results of a three-year study to determine the fate of imidacloprid residues in hive matrices and to assess chronic sublethal effects on whole honey bee colonies fed supplemental pollen diet containing imidacloprid at 5, 20 and 100 μg/kg over multiple brood cycles. Various endpoints of colony performance and foraging behavior were measured during and after exposure, including winter survival. Imidacloprid residues became diluted or non-detectable within colonies due to the processing of beebread and honey and the rapid metabolism of the chemical. Imidacloprid exposure doses up to 100 μg/kg had no significant effects on foraging activity or other colony performance indicators during and shortly after exposure. Diseases and pest species did not affect colony health but infestations of Varroa mites were significantly higher in exposed colonies. Honey stores indicated that exposed colonies may have avoided the contaminated food. Imidacloprid dose effects was delayed later in the summer, when colonies exposed to 20 and 100 μg/kg experienced higher rates of queen failure and broodless periods, which led to weaker colonies going into the winter. Pooled over two years, winter survival of colonies averaged 85.7, 72.4, 61.2 and 59.2% in the control, 5, 20 and 100 μg/kg treatment groups, respectively. Analysis of colony survival data showed a significant dose effect, and all contrast tests comparing survival between control and treatment groups were significant, except for colonies exposed to 5 μg/kg. Given the weight of evidence, chronic exposure to imidacloprid at the higher range of field doses (20 to 100 μg/kg) in pollen of certain treated crops could cause negative impacts on honey bee colony health and reduced overwintering success, but the most likely encountered high range of field doses relevant for seed-treated crops (5 μg/kg) had negligible effects on colony health and are unlikely a sole cause of colony declines. PMID:25786127

  17. Performance of honey bee colonies under a long-lasting dietary exposure to sublethal concentrations of the neonicotinoid insecticide thiacloprid.

    Science.gov (United States)

    Siede, Reinhold; Faust, Lena; Meixner, Marina D; Maus, Christian; Grünewald, Bernd; Büchler, Ralph

    2017-07-01

    Substantial honey bee colony losses have occurred periodically in the last decades. The drivers for these losses are not fully understood. The influence of pests and pathogens are beyond dispute, but in addition, chronic exposure to sublethal concentrations of pesticides has been suggested to affect the performance of honey bee colonies. This study aims to elucidate the potential effects of a chronic exposure to sublethal concentrations (one realistic worst-case concentration) of the neonicotinoid thiacloprid to honey bee colonies in a three year replicated colony feeding study. Thiacloprid did not significantly affect the colony strength. No differences between treatment and control were observed for the mortality of bees, the infestation with the parasitic mite Varroa destructor and the infection levels of viruses. No colony losses occurred during the overwintering seasons. Furthermore, thiacloprid did not influence the constitutive expression of the immunity-related hymenoptaecin gene. However, upregulation of hymenoptaecin expression as a response to bacterial challenge was less pronounced in exposed bees than in control bees. Under field conditions, bee colonies are not adversely affected by a long-lasting exposure to sublethal concentrations of thiacloprid. No indications were found that field-realistic and higher doses exerted a biologically significant effect on colony performance. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  18. Toxicity of polybrominated diphenyl ethers (de-71) in chicken (Gallus gallus), mallard (Anas platyrhynchos), and American kestrel (Falco sparverius) embryos and hatchlings

    Science.gov (United States)

    McKernan, M.A.; Rattner, B.A.; Hale, R.C.; Ottinger, M.A.

    2009-01-01

    Embryonic survival, pipping and hatching success, and sublethal biochemical, endocrine, and histological endpoints were examined in hatchling chickens (Gallus gallus), mallards (Anas platyrhynchos), and American kestrels (Falco sparverius) following air cell administration of a pentabrominated diphenyl ether (penta-BDE; DE-71) mixture (0.01-20 mu g/g egg) or polychlorinated biphenyl (PCB) congener 126 (3,3', 4,4', 5-pentachlorobiphenyl; 0.002 mu g/g egg). The penta-BDE decreased pipping and hatching success at concentrations of 10 and 20 mu g/g egg in kestrels but had no effect on survival endpoints in chickens or mallards. Sublethal effects in hatchling chickens included ethoxyresorufin-O-dealkylase (EROD) induction and histological changes in the bursa, but these responses were not observed in other species. Polychlorinated biphenyl congener 126 (positive control) reduced survival endpoints in chicken and kestrel embryos and caused sublethal effects (EROD induction, reduced bursal mass and follicle size) in chickens. Mallards were clearly less sensitive than the other species to administered penta-BDE and PCB 126. In a second experiment, the absorption of penta-BDE (11.1 mu g/g egg, air cell administered during early development) into the contents of chicken and kestrel eggs was determined at various intervals (24 h postinjection, midincubation, and pipping). By pipping, 29% of the penta-BDE administered dose was present in the egg contents in chickens, and 18% of the administered dose was present in kestrel egg contents. Based on uptake in kestrels, the lowest-observed-effect level on pipping and hatching success may be as low as 1.8 mu g total penta-BDE/g egg, which approaches concentrations detected in eggs of free-ranging birds. Because some penta-BDE congeners are still increasing in the environment, the toxic effects observed in the present study are cause for concern in wildlife.

  19. Effects of chronic exposure to tributyltin on tissue-specific cytochrome P450 1 regulation in juvenile common carp.

    Science.gov (United States)

    Li, Zhi-Hua; Zhong, Li-Qiao; Mu, Wei-Na; Wu, Yan-Hua

    2016-01-01

    1. The purpose of this study was to compare tributyltin (TBT)-induced cytochrome P450 1 (CYP450 1) regulation in liver, gills and muscle of juvenile common carp (Cyprinus carpio). 2. Fish were exposed to sublethal concentrations of TBT (75, 0.75 and 7.5 μg/L) for 60 days. CYP450 1A was measured at the enzyme activity level as 7-ethoxyresorufin-O-deethylase (EROD) activity, as well as the mRNA expression of CYP450 1 family genes (CYP1A, CYP1B, CYP1C1 and CYP1C2) in fish tissues. 3. Based on the results, the liver displayed the highest absolute levels of EROD activity, both under nonexposed and exposed conditions. Additional, EROD activities and CYP1A gene levels showed a good correlation in all three organs. According to the mRNA expression of CYP450 1 family genes, it suggested that CYP1A was to accommodate most EROD activity in fish, but other CYP450 forms also involved in this proceeding. 4. Overall, the study revealed both similarities and differences in the concentration-dependent CYP450 1 responses of the three target organs, which could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity.

  20. Photorefractive keratectomy (PRK) at 193 nm using an erodible mask: new developments and clinical progress

    Science.gov (United States)

    Gordon, Michael; Seiler, Theo; Carey, Joseph P.; Friedman, Marc D.; Johnsson, N. M. F.; King, Michael C.; Muller, David F.

    1993-06-01

    This paper reports on our progress using an erodible mask to perform photorefractive keratectomy (PRK) for the correction of myopic astigmatism. We describe modifications to the mask, the mask eye cup and the surgical microscope aimed at simplifying the procedure and improving the ergonomics of the hardware. We report the clinical results of the post-op exam for 20 patients who have undergone PRK for myopic astigmatism under a Phase IIA study. The results compare favorably with an earlier Phase IIA study for performing PRK with a computer-controlled iris. Most important, the clinical data show the absence of any significant corneal haze and no significant decrease in spectacle corrected visual acuity. Although more long term follow-up is needed, the preliminary results support the safety and effectiveness of using an erodible mask to perform PRK for myopic astigmatism.

  1. Predicting sublethal effects of herbicides on terrestrial non-crop plant species in the field from greenhouse data

    International Nuclear Information System (INIS)

    Riemens, Marleen M.; Dueck, Thom; Kempenaar, Corne

    2008-01-01

    Guidelines provided by OECD and EPPO allow the use of data obtained in greenhouse experiments in the risk assessment for pesticides to non-target terrestrial plants in the field. The present study was undertaken to investigate the predictability of effects on field-grown plants using greenhouse data. In addition, the influence of plant development stage on plant sensitivity and herbicide efficacy, the influence of the surrounding vegetation on individual plant sensitivity and of sublethal herbicide doses on the biomass, recovery and reproduction of non-crop plants was studied. Results show that in the future, it might well be possible to translate results from greenhouse experiments to field situations, given sufficient experimental data. The results also suggest consequences at the population level. Even when only marginal effects on the biomass of non-target plants are expected, their seed production and thereby survival at the population level may be negatively affected. - The response of greenhouse-grown wild plant species to herbicide exposure could be related to the response of the same species when grown in the field

  2. Resuspended contaminated sediments cause sublethal stress to oysters: A biomarker differentiates total suspended solids and contaminant effects.

    Science.gov (United States)

    Edge, Katelyn J; Dafforn, Katherine A; Simpson, Stuart L; Ringwood, Amy H; Johnston, Emma L

    2015-06-01

    Resuspended contaminated sediments represent an important route of contaminant exposure for aquatic organisms. During resuspension events, filter-feeding organisms are exposed to contaminants, in both the dissolved form (at the gills) and the particulate form (in the digestive system). In addition, these organisms must manage the physical stress associated with an increase in total suspended solids (TSS). To date, few studies have experimentally compared the contributions to biological stress of contaminated and clean suspended solids. The authors mixed field-collected sediments (cellular biomarkers (lysosomal membrane stability, lipid peroxidation, and glutathione) were measured to evaluate sublethal toxicity. Lysosomal membrane stability was the most sensitive biomarker for distinguishing effects from resuspended contaminated sediments, as increasing amounts of contaminated TSS increased lysosomal membrane destabilization. The authors' results illustrate the importance of considering contaminant exposures from resuspended sediments when assessing the toxicity of contaminants to aquatic organisms. © 2015 SETAC.

  3. Assessing Sub-Lethal Impacts of Petroleum Compounds on Marine Benthic Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lindgren, J. Fredrik

    2012-07-01

    Petroleum and its different distillates commonly end up in the marine environment. One source of these additions is discharges originating from shipping activities; accidents, ship wrecks, operational spills etc. Depending on several different factors that govern the fate of petroleum released into the marine environment the effects of the discharge will differ, from acute toxic to long term sub-lethal effects. While effects on biota from large spills have thoroughly been investigated in the past long term sub-lethal effects are somewhat less examined. Therefore the objective of this thesis has been to develop and apply a method to analyze what effects low concentrations of petroleum, which often ends up in marine sediments, have on benthic sediment biota. Ecotoxicological endpoints that were evaluated were density changes of meiofauna and variations in the microbial community function, measured as inorganic nutrient fluxes over the sediment-water interface the potential to perform a metabolic process. These types of organisms are two important key players in marine benthic sedimentary habitats, performing ecosystem services such as degradation of organic matter, recycling of nutrients and various pollutants and they constitute a carbon link to higher trophic levels. As manual classification of meiofauna is very time-consuming process including an extended learning process for the taxonomist, this thesis is in its first part focused at the field of automatic classification. To classify meiofaunal communities a novel technique was developed where the image analysis software ZooImage was adapted to automatically classify higher taxonomic taxa of meiofauna, with successful results. The technique was evaluated by classifying meiofaunal communities from five different depths in the Gullmar Fjord, Sweden. The accuracy of the analyses was tested using ZooImage's internal 10-fold cross-validation method, and by comparing digitalized samples from the different sites

  4. Effects of recombinant human granulocyte colony-stimulating factor on central and peripheral T lymphocyte reconstitution after sublethal irradiation in mice

    International Nuclear Information System (INIS)

    Zhao Hongxia; Guo Mei; Sun Xuedong; Ai Huisheng; Sun Wanjun; Hu Hailan; Wei Li

    2013-01-01

    Granulocyte colony-stimulating factor (G-CSF) is one of the most critical cytokines used for the treatment of acute radiation syndrome (ARS). In addition to the hematopoietic effects of G-CSF on the differentiation and proliferation of myeloid progenitor cells, G-CSF is also known to have immunomodulatory effects. The aim of the present study was to investigate whether G-CSF could accelerate central and peripheral T lymphocyte recovery after a sublethal dose of irradiation. Female BALB/c mice were subjected to 6 Gy of total body irradiation and then were treated with either 100 μg/kg G-CSF or an equal volume of PBS once daily for 14 days. Percentages of thymocyte subpopulations including CD4- CD8-, CD4+ CD8+, CD4+ CD8- and CD4- CD8+ T cells, peripheral CD3+, CD4+ and CD8+ cells were analyzed by flow cytometry. Recent thymic emigrants (RTEs) were assessed by real-time polymerase chain reaction (PCR) using primers specific to the 257-bp T cell receptor rearrangement excision circles (sjTRECs). The proliferative capacity of splenic mononuclear cells upon exposure to ConA was measured by using the Cell Count Kit-8 (CCK-8). G-CSF treatment promoted thymocyte regeneration, accelerated the recovery of CD4+ CD8+ cells and increased the frequency of thymocyte sjTRECs. These effects were more prominent at early time points (Day 28) after irradiation. G-CSF also increased the rate of recovery of peripheral CD3+, CD4+ and CD8+ cells and shortened the period of severe lymphopenia following irradiation. G-CSF also increased the splenic mononuclear cell mitotic responsiveness to ConA more than control-treated cells. Our results show that G-CSF accelerates T cell recovery through both thymic-dependent and thymic-independent pathways, which could be used to increase the rate of immune reconstitution after sublethal irradiation. (author)

  5. ASSESSMENT SPATIAL VARIABILITY OF SOIL ERODIBILITY BY USING OF GEOSTATISTIC AND GIS (Case study MEHR watershed of SABZEVAR

    Directory of Open Access Journals (Sweden)

    Ayoubi, S.A

    2005-05-01

    Full Text Available Soil erodibility is one of the key factors on some sediment and soil erosion models such as USLE, MUSLE, RUSLE, AUSLE (USLE modified in LS factor and MMF and represents like K factor and is function of particle distribution, organic mater, soil structure and ermeability. Traditional methods do not take spatial variability and estimate precision of variables in to consideration and amount of them are constant across the whole of soil series .This study was performed to assess spatial variability of soil erodibility and its relevant variables at MEHR watershed from Khorasan province, in northern Iran. Interested network was designed by 110 samples like nested- systematic with distance about 50, 100, 250 and 500 meter across the study area by preparing point map at GIS. Sampling points were identified in field by an Global Positioning system. Soil sampling was done at depth of 0-5cm of ground surface and permeability was studied at depth of 5-30 cm. Some soil properties such as particle distribution and organic mater were measured at laboratory. Particle size distribution was determined by Hydrometer method and Organic matter was measured by wet oxidation approach. Then spatial analysis was done. Variography analysis on soil attributes according to soil erodibility, showed that Gaussian, exponential and spherical models were the most models to predict spatial variability of soil parameters. The range of spatial dependencies was changed from 320 to 3200 m. Soil attribute maps prepared by kriging technique using models parameters. Then soil attributes were composed by Wischmeier (1978 formula in Illwis media to calculate K factor. Amount of soil erodibility changed from 0.13 to 0.91 that it's maximum and minimum was identified in east and southwest of studiedarea. Soil spatial variability pattern, is similar to silt pattern due to high effect of silt on soil rodibility, Also that is partially confirmed with geology map, indicated which soil

  6. Radioprotective effects in mice by a single dose of subcutaneous administration of cobaltous chloride post γ-rays irradiation with a sublethal dose

    International Nuclear Information System (INIS)

    Izumo, Yoshiro; Ogata, Hiromitsu

    1993-01-01

    Radioprotective effects were investigated in mice which received subcutaneously a single dose of each inorganic metal: Co, Cu, Rb, Sr, Mo and W 24 hours post irradiation of 60 Co γ-rays with a sublethal dose. The effects were observed in mice injected with Co at an optimum dosage of 20 mg/kg·body weight. Then to elucidate mechanisms of the effects, mice were injected with Co containing the radioactive tracer ( 60 Co) following the radiation exposure, measured elimination of the radioactivity for 7 days, then sacrificed and divided to some tissues and organs. The radioactivity in whole body during this period resulted in a markedly higher retention than that for mice injected with [ 60 Co] alone, as well as liver in the organs. These higher retentions appeared to be related to the radioprotective effects. (author)

  7. Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells

    Energy Technology Data Exchange (ETDEWEB)

    Pavlikova, Nela, E-mail: nela.pavlikova@lf3.cuni.cz [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic); Smetana, Pavel [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic); Halada, Petr [Laboratory of Molecular Structure Characterization, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague (Czech Republic); Kovar, Jan [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic)

    2015-10-15

    Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. - Highlights: • Epidemiologic studies connect pollution with incidence of diabetes mellitus. • We explored the effect of DDT and DDE on protein expression in the NES2Y pancreatic beta cell line. • One month exposure to three sublethal concentrations of DDT and DDE was employed. • Expression of alpha-enolase, actin

  8. Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells

    International Nuclear Information System (INIS)

    Pavlikova, Nela; Smetana, Pavel; Halada, Petr; Kovar, Jan

    2015-01-01

    Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. - Highlights: • Epidemiologic studies connect pollution with incidence of diabetes mellitus. • We explored the effect of DDT and DDE on protein expression in the NES2Y pancreatic beta cell line. • One month exposure to three sublethal concentrations of DDT and DDE was employed. • Expression of alpha-enolase, actin

  9. Low-salinity stress in the American lobster, Homarus americanus, after chronic sublethal exposure to cadmium: Biochemical effects

    Energy Technology Data Exchange (ETDEWEB)

    Gould, E

    1980-01-01

    Lobsters (Homarus americanus) were exposed to cadmium (6 ..mu..g 1sup(-1), 30 days) in flowing seawater, then held for 7 days in aerated 'clean' seawater at either ambient (27 per mill) or low (17 per mill) salinity. Cadmium exposure alone (ambient salinity) induced a general elevation of enzyme activity (heart, antennal gland, and muscle MDH; heart LDH and GPI), despite the probability of some clearance of cadmium from body tissues during the 'clean' seawater holding period. Low-salinity alone (non-exposed lobsters) caused a decrease of enzyme activity (AAT, LDH, GPI, PK) in most tissues examined, except for tail muscle IDH, the activity of which was increased, and MDH, which was significantly elevated above ambient controls in all tissues except heart. Most low-salinity effects were observed in tail muscle, and most cadmium effects, in heart; low-salinity effects outnumbered cadmium stress by nine to four. In heart and tail muscle of cadmium-exposed lobsters held at low salinity, each of the two stresses apparently operated to nullify the other's effects. The most prominent single biochemical response to these sublethal stresses was the elevation of MDH activity. The ratio MDH:LDH gave the clearest indication of overall relative stress.

  10. The Influence of Eroded Blades on Wind Turbine Performance Using Numerical Simulations

    Directory of Open Access Journals (Sweden)

    Matthias Schramm

    2017-09-01

    Full Text Available During their operation, wind turbine blades are eroded due to rain and hail, or they are contaminated with insects. Since the relative inflow velocity is higher at the outer than at the inner part of the blades, erosion occurs mostly at the outer blade region. In order to prevent strong erosion, it is possible to install a leading edge protection, which can be applied to the blades after the initial installation, but changes the shape of the initial airfoil sections. It is unclear how this modification influences the aerodynamic performance of the turbine. Hence, it is investigated in this work. The NREL 5 MW turbine is simulated with clean and eroded blades, which are compared to coated blades equipped with leading edge protection. Aerodynamic polars are generated by means of Computational Fluid Dynamics, and load calculations are conducted using the blade element momentum theory. The analysis in this work shows that, compared to clean rotor blades, the worse aerodynamic behaviour of strongly eroded blades can lead to power losses of 9 % . In contrast, coated blades only have a small impact on the turbine power of less than 1 % .

  11. Dynamic replacement and loss of soil carbon on eroding cropland

    Science.gov (United States)

    Harden, J.W.; Sharpe, J.M.; Parton, W.J.; Ojima, D.S.; Fries, T.L.; Huntington, T.G.; Dabney, S.M.

    1999-01-01

    Links between erosion/sedimentation history and soil carbon cycling were examined in a highly erosive setting in Mississippi loess soils. We sampled soils on (relatively) undisturbed and cropped hillslopes and measured C, N, 14C, and CO2 flux to characterize carbon storage and dynamics and to parameterize Century and spreadsheet 14C models for different erosion and tillage histories. For this site, where 100 years of intensive cotton cropping were followed by fertilization and contour plowing, there was an initial and dramatic decline in soil carbon content from 1870 to 1950, followed by a dramatic increase in soil carbon. Soil erosion amplifies C loss and recovery: About 100% of the original, prehistoric soil carbon was likely lost over 127 years of intensive land use, but about 30% of that carbon was replaced after 1950. The eroded cropland was therefore a local sink for CO2 since the 1950s. However, a net CO2 sink requires a full accounting of eroded carbon, which in turn requires that decomposition rates in lower slopes or wetlands be reduced to about 20% of the upland value. As a result, erosion may induce unaccounted sinks or sources of CO2, depending on the fate of eroded carbon and its protection from decomposition. For erosion rates typical of the United States, the sink terms may be large enough (1 Gt yr-1, back-of-the-envelope) to warrant a careful accounting of site management, cropping, and fertilization histories, as well as burial rates, for a more meaningful global assessment.

  12. Erodibility of calcareous soils as influenced by land use and intrinsic soil properties in a semiarid region of central Iran.

    Science.gov (United States)

    Ayoubi, Shamsollah; Mokhtari, Javad; Mosaddeghi, Mohammad Reza; Zeraatpisheh, Mojtaba

    2018-03-06

    The most important properties affecting the soil loss and runoff were investigated, and the effects of land use on the soil properties, together with the erodibility indices in a semiarid zone, central Iran, were evaluated. The locations of 100 positions were acquired by cLHS and 0-5-cm surface soil layer samples were used for laboratory analyses from the Borujen Region, Chaharmahal-Va-Bakhtiari Province, central Iran. To measure in situ runoff and soil erodibility of three different land uses comprising dryland, irrigated farming, and rangeland, a portable rainfall simulator was used. The results showed that the high variations (coefficient of variation, CV) were obtained for electrical conductivity (EC), mean weight diameter (MWD), soil organic carbon (SOC), and soil erodibility indices including runoff volume, soil loss, and sediment concentration (CV ~ 43.6-77.4%). Soil erodibility indices showed positive and significant correlations with bulk density and negative correlations with SOC, MWD, clay content, and soil shear strength in the area under investigation. The values of runoff in the dryland, irrigated farming, and rangeland were found 1.5, 28.9, and 58.7 cm 3 ; soil loss in the dryland, irrigated farming, and rangeland were observed 0.25, 2.96, and 76.8 g; and the amount of sediment concentration in the dryland, irrigated farming, and rangeland were found 0.01, 0.11, and 0.15 g cm -3 . It is suggested that further investigations should be carried out on soil erodibility and the potential of sediment yield in various land uses with varying topography and soil properties in semiarid regions of Iran facing the high risk of soil loss.

  13. 75 FR 75961 - Notice of Implementation of the Wind Erosion Prediction System for Soil Erodibility System...

    Science.gov (United States)

    2010-12-07

    ... implementation of the WEPS system does not affect the Highly Erodible Map Unit List contained in the NRCS Field Office Technical Guide as of January 1, 1990. This 1990 list will continue to be used for all erodibility... plant damage, and predict PM-10 emissions when wind speeds exceed the erosion threshold. The WEPS model...

  14. Sublethal concentration of H2O2 enhances the protective effect of mesenchymal stem cells in rat model of spinal cord injury.

    Science.gov (United States)

    Rahimi, Asrin; Amiri, Iraj; Roushandeh, Amaneh Mohammadi; Choshali, Zoleikha Golipour; Alizadeh, Zohreh; Artimani, Tayebeh; Afshar, Saeid; Asl, Sara Soleimani

    2018-03-01

    To investigate the effect of H 2 O 2 on the migration and antioxidant defense of mesenchymal stem cells (MSCs) and the neurotrophic effects of H 2 O 2 -treated MSCs on spinal cord injury (SCI). Sublethal concentrations of H 2 O 2 decreased cell migration and expression of CXCR4 and CCR2 as well as Nrf2 expression in MSCs. In the second phase, transplantation of treated and untreated MSCs to SCI caused minor changes in locomotor dysfunction. There was a significantly difference between cell-treated and spinal cord injury groups in expression of BDNF (brain-derived neurotrophic factor). Transplantation of H 2 O 2 -treated cells caused an increase in BDNF expression compared to non-treated cells. Transplantation of H 2 O 2 -treated stem cells may have protective effects against SCI through by increasing neurotrophic factors.

  15. Eroded Layered Material in Southwest Utopia Planitia

    Science.gov (United States)

    1999-01-01

    Images from the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC)dramatically illustrate that many places on the red planet have outcrops of layered geologic materials. The two pictures above show the remains of layered material inside craters in southwestern Utopia Planitia (see inset for detailed view). These remnant layers indicate that the craters--and perhaps the plains that surround them--were once buried beneath a deposit that has since been eroded away. This theme of layered outcrops and exhumed craters appears to be one of the dominant observations that MGS MOC has made--to date--about Mars. The origin and composition of the layered material--and its ultimate fate once it was largely eroded away--are unknown. Each of the two pictures shown here covers an area about 4 kilometers (2.5 miles)by 6.3 kilometers (3.9 miles). Illumination is from the lower right. These are subframes of a single MOC image acquired in July 1998 during the MGS Science Phasing Orbits imaging campaign. This figure was presented at the 30th Lunar and Planetary Science Conference in Houston, Texas, March 1999. Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  16. Sublethal toxicity of nano-titanium dioxide and carbon nanotubes in a sediment dwelling marine polychaete

    Energy Technology Data Exchange (ETDEWEB)

    Galloway, Tamara, E-mail: t.s.galloway@exeter.ac.u [School of Biosciences, Hatherly Laboratories, University of Exeter, EX4 4PS, Exeter, Devon (United Kingdom); Lewis, Ceri [School of Biosciences, Hatherly Laboratories, University of Exeter, EX4 4PS, Exeter, Devon (United Kingdom); Dolciotti, Ida [Universita Politecnica delle Marche, Institute of Biology and Genetics, Via Ranieri, Monte Dago, 60121 Ancona (Italy); Johnston, Blair D. [School of Biosciences, Hatherly Laboratories, University of Exeter, EX4 4PS, Exeter, Devon (United Kingdom); Moger, Julian [School of Physics, Stocker Road, University of Exeter, Devon EX4 4QL (United Kingdom); Regoli, Francesco [Universita Politecnica delle Marche, Institute of Biology and Genetics, Via Ranieri, Monte Dago, 60121 Ancona (Italy)

    2010-05-15

    The ecotoxicology of manufactured nanoparticles (MNPs) in estuarine environments is not well understood. Here we explore the hypothesis that nanoTiO{sub 2} and single walled nanotubes (SWNT) cause sublethal impacts to the infaunal species Arenicola marina (lugworm) exposed through natural sediments. Using a 10 day OECD/ASTM 1990 acute toxicity test, no significant effects were seen for SWNT up to 0.03 g/kg and no uptake of SWNTs into tissues was observed. A significant decrease in casting rate (P = 0.018), increase in cellular damage (P = 0.04) and DNA damage in coelomocytes (P = 0.008) was measured for nanoTiO{sub 2}, with a preliminary LOEC of 1 g/kg. Coherent anti-stokes Raman scattering microscopy (CARS) located aggregates of TiO{sub 2} of >200 nm within the lumen of the gut and adhered to the outer epithelium of the worms, although no visible uptake of particles into tissues was detected. - This study explores the hypothesis that nano-TiO{sub 2} and single walled nanotubes (SWNT) can cause sublethal impacts to Arenicola marina exposed through natural sediments.

  17. 1H NMR metabolomics of earthworm exposure to sub-lethal concentrations of phenanthrene in soil

    International Nuclear Information System (INIS)

    Brown, Sarah A.E.; McKelvie, Jennifer R.; Simpson, Andre J.; Simpson, Myrna J.

    2010-01-01

    1 H NMR metabolomics was used to monitor earthworm responses to sub-lethal (50-1500 mg/kg) phenanthrene exposure in soil. Total phenanthrene was analyzed via soxhlet extraction, bioavailable phenanthrene was estimated by hydroxypropyl-β-cyclodextrin (HPCD) and 1-butanol extractions and sorption to soil was assessed by batch equilibration. Bioavailable phenanthrene (HPCD-extracted) comprised ∼65-97% of total phenanthrene added to the soil. Principal component analysis (PCA) showed differences in responses between exposed earthworms and controls after 48 h exposure. The metabolites that varied with exposure included amino acids (isoleucine, alanine and glutamine) and maltose. PLS models indicated that earthworm response is positively correlated to both total phenanthrene concentration and bioavailable (HPCD-extracted) phenanthrene in a freshly spiked, unaged soil. These results show that metabolomics is a powerful, direct technique that may be used to monitor contaminant bioavailability and toxicity of sub-lethal concentrations of contaminants in the environment. These initial findings warrant further metabolomic studies with aged contaminated soils. - 1 H NMR metabolomics is used to directly monitor metabolic responses of Eisenia fetida after 48 h of exposure to sub-lethal concentrations of phenanthrene in soil.

  18. Bond strength and interfacial morphology of orthodontic brackets bonded to eroded enamel treated with calcium silicate-sodium phosphate salts or resin infiltration.

    Science.gov (United States)

    Costenoble, Aline; Vennat, Elsa; Attal, Jean-Pierre; Dursun, Elisabeth

    2016-11-01

     To investigate the shear bond strength (SBS) of orthodontic brackets bonded to eroded enamel treated with preventive approaches and to examine the enamel/bracket interfaces.  Ninety-one brackets were bonded to seven groups of enamel samples: sound; eroded; eroded+treated with calcium silicate-sodium phosphate salts (CSP); eroded+infiltrated by ICON ® ; eroded+infiltrated by ICON ® and brackets bonded with 1-month delay; eroded+infiltrated by an experimental resin; and eroded+infiltrated by an experimental resin and brackets bonded with 1-month delay. For each group, 12 samples were tested in SBS and bond failure was assessed with the adhesive remnant index (ARI); one sample was examined using scanning electron microscopy (SEM).  Samples treated with CSP or infiltration showed no significant differences in SBS values with sound samples. Infiltrated samples followed by a delayed bonding showed lower SBS values. All of the values remained acceptable. The ARI scores were significantly higher for sound enamel, eroded, and treated with CSP groups than for all infiltrated samples. SEM examinations corroborated the findings.  Using CSP or resin infiltration before orthodontic bonding does not jeopardize the bonding quality. The orthodontic bonding should be performed shortly after the resin infiltration.

  19. Helicoverpa armigera (Lepidoptera: Noctuidae) larvae that survive sublethal doses of nucleopolyhedrovirus exhibit high metabolic rates.

    Science.gov (United States)

    Bouwer, Gustav; Nardini, Luisa; Duncan, Frances D

    2009-04-01

    To determine the effect of sublethal doses of Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HearSNPV) on the metabolic rate of H. armigera, the respiration rates of third instar H. armigera larvae inoculated with sublethal doses of HearSNPV were evaluated. Respiration rates, measured as the rate of CO(2) production (VCO(2)), were recorded daily using closed-system respirometry. By 4 days post-inoculation (dpi), the metabolic rates of LD(25) or LD(75) survivors were significantly higher than that of uninoculated controls. When dose data were pooled, the VCO(2) values of larvae that survived inoculation (0.0288mlh(-1)), the uninoculated controls (0.0250mlh(-1)), and the larvae that did not survive inoculation (0.0199mlh(-1)) differed significantly from one another. At 4dpi, the VCO(2) of the uninoculated controls were significantly lower than the VCO(2) of inoculation survivors, but significantly higher than the VCO(2) of inoculation non-survivors. Inoculation survivors may have had high metabolic rates due to a combination of viral replication, organ damage, and an energy-intensive induced cellular immune response. The high 4dpi metabolic rate of inoculation survivors may reflect an effective immune response and may be seen as the metabolic signature of larvae that are in the process of surviving inoculation with HearSNPV.

  20. Sublethal damages: their nature and repair

    Energy Technology Data Exchange (ETDEWEB)

    Saenko, A.S.; Synzynys, B.I.; Trofimova, S.F. (Nauchno-Issledovatel' skij Inst. Meditsinskoj Radiologii, Obninsk (USSR)); Gotlib, V.Ya.; Pelevina, I.I. (AN SSSR, Moscow. Inst. Khimicheskoj Fiziki)

    1983-05-12

    The molecular nature of sublethal damage (SLD) arising after ionizing irradiation of cultured mammalian cells was considered on the basis of data on DNA repair and cell recovery after SLD observed in lymphosarcoma cells as well as of literature data. The rate of SLD recovery and that of restoration of the cell's ability to initiate DNA synthesis were shown to be similar in new replicons. These data along with knowledge about the role of exchange type chromosomal aberrations in reproductive death permitted us to propose the hypothesis that conformational changes of chromatine - most probably, relaxation of condensed chromosomal material - are damage registered as SLD at the cellular level. Double-strand breaks and a slowly repaired part of DNA single-strand breaks are candidates for SLD.

  1. Avoidance behaviour and anxiety in rats irradiated with a sublethal dose of gamma-rays.

    Science.gov (United States)

    Tomášová, Lenka; Smajda, B; Bona, M

    2011-12-01

    The aim of this study was to assess, whether a sublethal dose of gamma-rays will influence the avoidance behaviour and anxiety in rats and whether the response to radiation depends on time of day of its application. Adult male Wistar rats were tested in elevated plus-maze, in hot plate test and in the light/dark box in 4 regular intervals during a day. After two weeks the animals were irradiated with a whole-body dose 6 Gy of gamma-rays. One day after irradiation the animals were repeatedly tested in the same way, as before irradiation. In the plus-maze test an increased level of anxiety was established. The irradiation significantly decreased the locomotor activity of rats, but the extent of exploratory and comfortable behaviour were not altered. After irradiation, an elevated aversion to the thermal stimulus was observed in the hot plate test. The effects of radiation were more pronounced in the light period of the day, than in the dark one. No significant differences in aversion to light were detected after irradiation. The obtained results indicate, that sublethal doses of ionizing radiation can markedly influence the reactivity of animals to adverse stimuli, their motoric activity and emotional status, as well.

  2. Predicting of soil erosion with regarding to rainfall erosivity and soil erodibility

    Science.gov (United States)

    Suif, Zuliziana; Razak, Mohd Amirun Anis Ab; Ahmad, Nordila

    2018-02-01

    The soil along the hill and slope are wearing away due to erosion and it can take place due to occurrence of weak and heavy rainfall. The aim of this study is to predict the soil erosion degree in Universiti Pertahanan Nasional Malaysia (UPNM) area focused on two major factor which is soil erodibility and rainfall erosivity. Soil erodibility is the possibilities of soil to detach and carried away during rainfall and runoff. The "ROM" scale was used in this study to determine the degree of soil erodibility, namely low, moderate, high, and very high. As for rainfall erosivity, the erosive power caused by rainfall that cause soil loss. A daily rainfall data collected from January to April was analyzed by using ROSE index classification to identify the potential risk of soil erosion. The result shows that the soil erodibilty are moderate at MTD`s hill, high at behind of block Lestari and Landslide MTD hill, and critical at behind the mess cadet. While, the highest rainfall erosivity was recorded in March and April. Overall, this study would benefit the organization greatly in saving cost in landslide protection as relevant authorities can take early measures repairing the most affected area of soil erosion.

  3. Wind-Eroded Silicate as a Source of Hydrogen Peroxide on Mars

    Science.gov (United States)

    Bak, E. N.; Merrison, J. P.; Jensen, S. K.; Nørnberg, P.; Finster, K.

    2014-07-01

    Laboratory simulations show that wind-eroded silicate can be a source of hydrogen peroxide. The ubiquitous, fine-grained silicate dust might thus explain the oxidizing properties of the martian soil and affect the preservation of organic compounds.

  4. Lethal and Sublethal Effects of Insecticides Used on Citrus, on the Ectoparasitoid Tamarixia radiata.

    Science.gov (United States)

    Beloti, Vitor Hugo; Alves, Gustavo Rodrigues; Araújo, Diogo Feliciano Dias; Picoli, Mateus Manara; Moral, Rafael de Andrade; Demétrio, Clarice Garcia Borges; Yamamoto, Pedro Takao

    2015-01-01

    Huanglongbing (HLB) is a disease associated with the bacteria "Candidatus Liberibacter spp." and has been devastating citrus orchards around the world. Its management involves control of the insect vector, the Asian citrus psyllid Diaphorina citri Kuwayama. However, the indiscriminate use of chemicals has caused pest outbreaks and eliminated the natural enemies of the vector, such as the parasitoid Tamarixia radiata (Waterston), the main agent for biological control of D. citri. This study assessed the lethal and sublethal effects of insecticides recommended for integrated production of citrus on the parasitoid T. radiata. When adult parasitoids were exposed to residues of 25 insecticides, 20% of them, i.e., gamma-cyhalothrin, etofenprox, azadirachtin, tebufenozide and pyriproxyfen, were considered as harmless (Class 1), 12% as slightly harmful (Class 2), 12% as moderately harmful (Class 3) and 56% as harmful (Class 4), according to the classification proposed by the IOBC/WPRS. Afterward, 14 insecticides (5 harmless and 9 harmful) were sprayed on the parasitoid pupae. Of the 14 insecticides tested, only the organophosphates dimethoate and chlorpyrifos affected the parasitoid emergence. The effects of insecticides on the parasitism capacity of adults exposed to residues of azadirachtin, etofenprox, gamma-cyhalothrin, pyriproxyfen and tebufenozide (harmless) were also evaluated. Tebufenozide and gamma-cyhalothrin affected the parasitism of the F0 generation, but did not affect the emergence of the F1 and F2 generations. Therefore, for an effective IPM program, selective insecticides or harmful pesticides to adult parasitoids could be used in the field, provided that the adults do not occur naturally and the chemical applications do not coincide with parasitoid releases.

  5. Lethal and Sublethal Effects of Insecticides Used on Citrus, on the Ectoparasitoid Tamarixia radiata.

    Directory of Open Access Journals (Sweden)

    Vitor Hugo Beloti

    Full Text Available Huanglongbing (HLB is a disease associated with the bacteria "Candidatus Liberibacter spp." and has been devastating citrus orchards around the world. Its management involves control of the insect vector, the Asian citrus psyllid Diaphorina citri Kuwayama. However, the indiscriminate use of chemicals has caused pest outbreaks and eliminated the natural enemies of the vector, such as the parasitoid Tamarixia radiata (Waterston, the main agent for biological control of D. citri. This study assessed the lethal and sublethal effects of insecticides recommended for integrated production of citrus on the parasitoid T. radiata. When adult parasitoids were exposed to residues of 25 insecticides, 20% of them, i.e., gamma-cyhalothrin, etofenprox, azadirachtin, tebufenozide and pyriproxyfen, were considered as harmless (Class 1, 12% as slightly harmful (Class 2, 12% as moderately harmful (Class 3 and 56% as harmful (Class 4, according to the classification proposed by the IOBC/WPRS. Afterward, 14 insecticides (5 harmless and 9 harmful were sprayed on the parasitoid pupae. Of the 14 insecticides tested, only the organophosphates dimethoate and chlorpyrifos affected the parasitoid emergence. The effects of insecticides on the parasitism capacity of adults exposed to residues of azadirachtin, etofenprox, gamma-cyhalothrin, pyriproxyfen and tebufenozide (harmless were also evaluated. Tebufenozide and gamma-cyhalothrin affected the parasitism of the F0 generation, but did not affect the emergence of the F1 and F2 generations. Therefore, for an effective IPM program, selective insecticides or harmful pesticides to adult parasitoids could be used in the field, provided that the adults do not occur naturally and the chemical applications do not coincide with parasitoid releases.

  6. Quality Uncertainty Erodes Trust in Science

    Directory of Open Access Journals (Sweden)

    Simine Vazire

    2017-02-01

    Full Text Available When consumers of science (readers and reviewers lack relevant details about the study design, data, and analyses, they cannot adequately evaluate the strength of a scientific study. Lack of transparency is common in science, and is encouraged by journals that place more emphasis on the aesthetic appeal of a manuscript than the robustness of its scientific claims. In doing this, journals are implicitly encouraging authors to do whatever it takes to obtain eye-catching results. To achieve this, researchers can use common research practices that beautify results at the expense of the robustness of those results (e.g., p-hacking. The problem is not engaging in these practices, but failing to disclose them. A car whose carburetor is duct-taped to the rest of the car might work perfectly fine, but the buyer has a right to know about the duct-taping. Without high levels of transparency in scientific publications, consumers of scientific manuscripts are in a similar position as buyers of used cars – they cannot reliably tell the difference between lemons and high quality findings. This phenomenon – quality uncertainty – has been shown to erode trust in economic markets, such as the used car market. The same problem threatens to erode trust in science. The solution is to increase transparency and give consumers of scientific research the information they need to accurately evaluate research. Transparency would also encourage researchers to be more careful in how they conduct their studies and write up their results. To make this happen, we must tie journals’ reputations to their practices regarding transparency. Reviewers hold a great deal of power to make this happen, by demanding the transparency needed to rigorously evaluate scientific manuscripts. The public expects transparency from science, and appropriately so – we should be held to a higher standard than used car salespeople.

  7. Incorporation of Fine-Grained Sediment Erodibility Measurements into Sediment Transport Modeling, Capitol Lake, Washington

    Science.gov (United States)

    Stevens, Andrew W.; Gelfenbaum, Guy; Elias, Edwin; Jones, Craig

    2008-01-01

    Capitol Lake was created in 1951 with the construction of a concrete dam and control gate that prevented salt-water intrusion into the newly formed lake and regulated flow of the Deschutes River into southern Puget Sound. Physical processes associated with the former tidally dominated estuary were altered, and the dam structure itself likely caused an increase in retention of sediment flowing into the lake from the Deschutes River. Several efforts to manage sediment accumulation in the lake, including dredging and the construction of sediment traps upriver, failed to stop the lake from filling with sediment. The Deschutes Estuary Feasibility Study (DEFS) was carried out to evaluate the possibility of removing the dam and restoring estuarine processes as an alternative ongoing lake management. An important component of DEFS was the creation of a hydrodynamic and sediment transport model of the restored Deschutes Estuary. Results from model simulations indicated that estuarine processes would be restored under each of four restoration alternatives, and that over time, the restored estuary would have morphological features similar to the predam estuary. The model also predicted that after dam-removal, a large portion of the sediment eroded from the lake bottom would be deposited near the Port of Olympia and a marina located in lower Budd Inlet seaward of the present dam. The volume of sediment transported downstream was a critical piece of information that managers needed to estimate the total cost of the proposed restoration project. However, the ability of the model to predict the magnitude of sediment transport in general and, in particular, the volume of sediment deposition in the port and marina was limited by a lack of information on the erodibility of fine-grained sediments in Capitol Lake. Cores at several sites throughout Capitol Lake were collected between October 31 and November 1, 2007. The erodibility of sediments in the cores was later determined in the

  8. Sublethal effects of the Exxon Valdez oil spill on herring embryos and larvae: morphological, cytogenetic; and histopathological assessments, 1989-1991

    International Nuclear Information System (INIS)

    Hose, J. E.; Marty, G. D.; Hinton, D. E.

    1996-01-01

    Extensive sublethal damage assessments were carried out on Pacific herring larvae following the Exxon Valdez oil spill. Egg masses were collected from oiled and non-oiled areas during 1989 to 1991, and incubated to hatch. The hatched larvae were evaluated for morphological deformities, cytogenetic abnormalities, and histopathological lesions. In 1989, herring larvae from the oiled areas showed high incidence of morphological deformities and cytogenetic abnormalities compared to larvae from non-oiled areas. There was no evidence of histopathological lesions. Identical assessments in 1990 and 1991 revealed no detectable oil-related developmental and genetic effects. In contrast, there was a marked decrease in survival, suggesting that that genetic damage at heavily oiled stations combined with severe morphological malformations mitigated against survival through the stressful larval period. 40 refs., 1 tab.,8 figs

  9. Erodibility of a mixed mudflat dominated by microphytobenthos and Cerastoderma edule, East Frisian Wadden Sea, Germany

    DEFF Research Database (Denmark)

    Andersen, Thorbjørn Joest; Lanuru, Mahatma; van Bernem, Carlo

    2010-01-01

    Sediment erodibility and a range of physical and biological parameters were measured at an intertidal site in the German Wadden Sea area in June, September and November 2002 and February and April 2003 in order to examine the influence of macrozoobenthos and microphytobenthos on sediment erodibil......Sediment erodibility and a range of physical and biological parameters were measured at an intertidal site in the German Wadden Sea area in June, September and November 2002 and February and April 2003 in order to examine the influence of macrozoobenthos and microphytobenthos on sediment...... erodibility and the temporal variation. The study site was a mixed mudflat situated in the mesotidal Baltrum-Langeoog tidal basin at the East Frisian barrier coast. The mud content at the site was about 35% and the filter-feeding cockle Cerastoderma edule was the dominating macrozoobenthic species (by biomass...... of C. edule will therefore probably increase the content of fine-grained sediments at the surface compared to an abiotic situation. Increasing the amount of fine-grained material in mixed sediments has previously been shown to reduce the erodibility of the sediments and C. edule will therefore...

  10. Frequent and seasonally variable sublethal anthrax infections are accompanied by short-lived immunity in an endemic system.

    Science.gov (United States)

    Cizauskas, Carrie A; Bellan, Steven E; Turner, Wendy C; Vance, Russell E; Getz, Wayne M

    2014-09-01

    Few studies have examined host-pathogen interactions in wildlife from an immunological perspective, particularly in the context of seasonal and longitudinal dynamics. In addition, though most ecological immunology studies employ serological antibody assays, endpoint titre determination is usually based on subjective criteria and needs to be made more objective. Despite the fact that anthrax is an ancient and emerging zoonotic infectious disease found world-wide, its natural ecology is not well understood. In particular, little is known about the adaptive immune responses of wild herbivore hosts against Bacillus anthracis. Working in the natural anthrax system of Etosha National Park, Namibia, we collected 154 serum samples from plains zebra (Equus quagga), 21 from springbok (Antidorcas marsupialis) and 45 from African elephants (Loxodonta africana) over 2-3 years, resampling individuals when possible for seasonal and longitudinal comparisons. We used enzyme-linked immunosorbent assays to measure anti-anthrax antibody titres and developed three increasingly conservative models to determine endpoint titres with more rigourous, objective mensuration. Between 52 and 87% of zebra, 0-15% of springbok and 3-52% of elephants had measurable anti-anthrax antibody titres, depending on the model used. While the ability of elephants and springbok to mount anti-anthrax adaptive immune responses is still equivocal, our results indicate that zebra in ENP often survive sublethal anthrax infections, encounter most B. anthracis in the wet season and can partially booster their immunity to B. anthracis. Thus, rather than being solely a lethal disease, anthrax often occurs as a sublethal infection in some susceptible hosts. Though we found that adaptive immunity to anthrax wanes rapidly, subsequent and frequent sublethal B. anthracis infections cause maturation of anti-anthrax immunity. By triggering host immune responses, these common sublethal infections may act as

  11. Mulching as a strategy to improve soil properties and reduce soil erodibility in coffee farming systems of Rwanda

    NARCIS (Netherlands)

    Nzeyimana, I.; Hartemink, A.E.; Ritsema, C.J.; Stroosnijder, L.; Huerta Lwanga, Esperanza; Geissen, V.

    2017-01-01

    In Rwanda, mulch is applied in coffee fields to control soil erosion. The objective of this paper is to quantify the effects of different types of mulch on soil properties and soil erodibility in coffee farming systems in three different agro-ecological zones of the highlands of Rwanda. The

  12. Impact of land use change on soil erodibility

    Directory of Open Access Journals (Sweden)

    F. Taleshian Jeloudar

    2018-01-01

    Full Text Available Vulnerability of soil separates to detachment by water is described as soil erodibility by Universal Soil Loss Equation which can be affected by land use change. In this study it was attempted to quantify the changes of Universal Soil Loss Equation K-factor and its soil driving factors in three land uses including rangeland, rainfed farming, and orchards in Babolrood watershed, northern Iran. Soil composite samples were obtained from two layers in three land uses, and the related soil physico-chemical properties were measured. The rainfed farming land use showed the highest clay contents, but the highest amounts of soil organic matter and sand particles were found in orchard land use. The high intensity of tillage led to the significant decrease of soil aggregate stability and permeability in the rainfed farming land use. The Universal Soil Loss Equation K-factor was negatively correlated with soil permeability (r=-0.77**. In rangeland, the K-factor (0.045 Mg h/MJ/mm was significantly higher and the particle size distribution had a great impact on the K-factor. The orchard land use, converted from the rangeland, did not show any increase of soils erodibility and can potentially be introduced as a good alternative land use in sloping areas. However, more detailed studies on environmental, social and economic aspects of this land use are needed.

  13. Determination of interrill soil erodibility coefficient based on Fuzzy and Fuzzy-Genetic Systems

    Directory of Open Access Journals (Sweden)

    Habib Palizvan Zand

    2017-02-01

    independent variables for development fuzzy and fuzzy- genetic models. For this reason their linguistic variables were defined and fuzzy models rules were written by Mamdani's fuzzy inference method. Then, the outputs of model defuzzified by centroid method. Once again, generation of membership functions and fuzzy rules base as well as optimization of fuzzy rule bases was performed by genetic algorithm, and the fuzzy functions were determined by optimized weight of membership functions and fuzzy rules. Results Discussion: Interrill erodibility parameters (Ki of the examined soils calculated at 3 rainfall rates using are listed in Table 2. The values ranged from 1.03 to 71.79 × 105 kg s m-4, depending on the soil and rainfall intensity. Results showed that the effect of rainfall intensity on Ki turned to be insignificant. This implies that Ki was independent of rainfall intensities. Results showed that the Triangular and Trapezoidal membership functions are better than the other membership functions for linguistic variables which used in this study. The values of R2, RMSE (Root mean square error and GMER (Geometric mean error ratio and GSDER (Geometric standard deviation of error ratio were 0.63, 592755, 1.31 and 1.38 for the fuzzy model, and, 0.70, 441942, 1.10 and 1.044 for the fuzzy- genetic model, respectively. Higher R2 and lower RMSE of the fuzzy – genetic model shows higher accuracy and efficiency of the fuzzy-genetic model. The GSDER criteria shows better matching of the fuzzy- genetic model estimated values with measured values. The GMER criteria shows lower over-estimation of the fuzzy- genetic model than fuzzy model. Conclusion: Fuzzy and fuzzy-genetic models which were designed with two input variables namely aggregates fractal dimensions and soil sand content, capable to predict of interrill erodibility coefficient of soils with reasonable accuracy. So using of these models for predicting of interrill erodibility is recommended.Optimization of fuzzy rule bases

  14. Distribution of Shrubland and Grassland Soil Erodibility on the Loess Plateau

    Directory of Open Access Journals (Sweden)

    Xiao Zhang

    2018-06-01

    Full Text Available Soil erosion is one of the most severe problems facing environments and has increased throughout the 20th century. Soil erodibility (K-factor is one of the important indicators of land degradation, and many models have been used to estimate K values. Although soil erodibility has been estimated, the comparison of different models and their usage at a regional scale and, in particular, for different land use types, need more research. Four of the most widely distributed land use types were selected to analyze, including introduced and natural grassland, as well as introduced and natural shrubland. Soil particle size, soil organic matter and other relevant soil properties were measured to estimate soil erodibility in the Loess Plateau. The results show that: (1 the erosion productivity impact calculator (EPIC model and SHIRAZI model are both suitable for the Loess Plateau, while the SHIRAZI model has the advantage of fewer parameters; (2 introduced grassland has better ability to protect both the 0–5 cm soils and 5–20 cm soils, while the differences between introduced and natural shrubland are not obvious at a catchment scale; (3 the K values of introduced grassland, natural grassland, introduced shrubland and natural shrubland in the 0–5 cm layer vary from 0.008 to 0.037, 0.031 to 0.046, 0.012 to 0.041 and 0.008 to 0.045 (t·hm2·h/(MJ·mm·hm2, while the values vary from 0.009 to 0.039, 0.032 to 0.046, 0.012 to 0.042 and 0.008 to 0.048 (t·hm2·h/(MJ·mm·hm2 in the 5–20 cm layer. The areas with a mean multiyear precipitation of 370–440 mm are the most important places for vegetation restoration construction management at a regional scale. A comprehensive balance between water conservation and soil conservation is needed and important when selecting the species used to vegetation restoration. This study provides suggestions for ecological restoration and provides a case study for the estimate of soil erodibility in arid and semiarid

  15. {sup 1}H NMR metabolomics of earthworm exposure to sub-lethal concentrations of phenanthrene in soil

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Sarah A.E.; McKelvie, Jennifer R.; Simpson, Andre J. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, Ontario, M1C 1A4 (Canada); Simpson, Myrna J., E-mail: myrna.simpson@utoronto.c [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, Ontario, M1C 1A4 (Canada)

    2010-06-15

    {sup 1}H NMR metabolomics was used to monitor earthworm responses to sub-lethal (50-1500 mg/kg) phenanthrene exposure in soil. Total phenanthrene was analyzed via soxhlet extraction, bioavailable phenanthrene was estimated by hydroxypropyl-beta-cyclodextrin (HPCD) and 1-butanol extractions and sorption to soil was assessed by batch equilibration. Bioavailable phenanthrene (HPCD-extracted) comprised approx65-97% of total phenanthrene added to the soil. Principal component analysis (PCA) showed differences in responses between exposed earthworms and controls after 48 h exposure. The metabolites that varied with exposure included amino acids (isoleucine, alanine and glutamine) and maltose. PLS models indicated that earthworm response is positively correlated to both total phenanthrene concentration and bioavailable (HPCD-extracted) phenanthrene in a freshly spiked, unaged soil. These results show that metabolomics is a powerful, direct technique that may be used to monitor contaminant bioavailability and toxicity of sub-lethal concentrations of contaminants in the environment. These initial findings warrant further metabolomic studies with aged contaminated soils. - {sup 1}H NMR metabolomics is used to directly monitor metabolic responses of Eisenia fetida after 48 h of exposure to sub-lethal concentrations of phenanthrene in soil.

  16. Sublethal dose of phoxim and Bombyx mori nucleopolyhedrovirus interact to elevate silkworm mortality.

    Science.gov (United States)

    Gu, ZhiYa; Li, FanChi; Hu, JingSheng; Ding, Chao; Wang, Chaoqian; Tian, JiangHai; Xue, Bin; Xu, KaiZun; Shen, WeiDe; Li, Bing

    2017-03-01

    Silkworm (Bombyx mori) is an economically important insect. It is relatively less resistant to certain chemicals and environment exposures such as pesticides and pathogens. After pesticide exposures, the silkworms are more susceptible to microbial infections. The mechanism underlying the susceptibility might be related to immune response and oxidative stress. A sublethal dose of phoxim combined with Bombyx mori nucleopolyhedrovirus (BmNPV) elevated the silkworm mortality at 96 h. We found a higher content of H 2 O 2 and increased levels of genes related to oxidative stress and immune response after treatment with a sublethal dose of phoxim for 24 h or 48 h. However, such response decreased with longer pesticide treatment. Mortality increased by 44% when B. mori was exposed to combined treatment with BmNPV and phoxim rather than BmNPV alone. The level of examined immune-related and oxidative-stress-related genes significantly decreased in the combined treatment group compared with the BmNPV group. Our results indicated that, with long-term exposure to pesticides such as OPs, even at sublethal dose, the oxidative stress response and immune responses in silkworm were inhibited, which may lead to further immune impairment and accumulation of oxidative stress, resulting in susceptibility to the virus and harm to the silkworm. Our study provided insights for understanding the susceptibility to pathogen after pesticide exposures, which may promote the development of better pesticide controls to avoid significant economic losses. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  17. Continuum modeling of ion-beam eroded surfaces under normal incidence: Impact of stochastic fluctuations

    International Nuclear Information System (INIS)

    Dreimann, Karsten; Linz, Stefan J.

    2010-01-01

    Graphical abstract: Deterministic surface pattern (left) and its stochastic counterpart (right) arising in a stochastic damped Kuramoto-Sivashinsky equation that serves as a model equation for ion-beam eroded surfaces and is systematically investigated. - Abstract: Using a recently proposed field equation for the surface evolution of ion-beam eroded semiconductor target materials under normal incidence, we systematically explore the impact of additive stochastic fluctuations that are permanently present during the erosion process. Specifically, we investigate the dependence of the surface roughness, the underlying pattern forming properties and the bifurcation behavior on the strength of the fluctuations.

  18. Effect of biocrust: study of mechanical and hydraulic properties and erodibility

    Science.gov (United States)

    Slavík, Martin; Bruthans, Jiří; Schweigstillová, Jana

    2016-04-01

    It is well-known that lichens and other organisms forming crust on soil or rock surface play important role in weathering but may also protect underlying material from fast erosion. So far, there have been only few measurements comparing mechanical or hydraulic properties of biocrust with its subsurface on locked sand and friable sandstones, so the overall effect of the biocrust is not well-understood. Objective of our study is to quantify the effect of the biocrust on mechanical and hydraulic properties of friable sandstone and locked sand of Cretaceous age in six different localities with varying aspect and inclination and age of exposure in sandpit Strelec (Czech Rep.). On the artificial exposures, biocrust developed within last 10-30 years. Beside measurements of mechanical and hydraulic properties, SEM and mercury intrusion porosimetry in crust and subsurface was performed. Drilling resistance technique was found an excellent method to distinguish the biocrust from its subsurface (~3 mm thick biocrust has up to 12 times higher drilling resistance than underlying material). Surface zone with the biocrust has 3 - 25 times higher tensile strength than the subsurface material (1 - 25 kPa). In comparison with the subsurface, the biocrust is considerably less erodible (based on water jet testing). Biocrust saturated hydraulic conductivity is 15 - 240 times lower than the subsurface (6*10 -5 - 1*10 -4 m/s) and its permeability for water vapor is 4 - 9 times lower than subsurface. Presence of the biocrust slows down capillary absorption of water 4 - 25 times. The biocrust is thus forming firm surface which protects underlying material from rain and flowing water erosion and which considerably modifies its hydraulic properties. Material with crust exposed to calcination, leaching by concentrated peroxide and experiments with zymoliase enzyme strongly indicate that major contribution to crust hardening is provided by organic matter. Based on DNA sequencing the crust is

  19. Seasonal change of WEPP erodibility parameters on a fallow plot

    Science.gov (United States)

    D. K. McCool; S. Dun; J. Q. Wu; W. J. Elliot

    2011-01-01

    In cold regions, frozen soil has a significant influence on runoff and water erosion. Frozen soil can reduce infiltration capacity, and the freeze-thaw processes degrade soil cohesive strength and increase soil erodibility. In the Inland Pacific Northwest of the USA, major erosion events typically occur during winter from low-intensity rain, snowmelt, or both as frozen...

  20. Acute toxicity and sublethal effects of the mixture glyphosate (Roundup® Active and Cosmo-Flux®411F to anuran embryos and tadpoles of four Colombian species

    Directory of Open Access Journals (Sweden)

    Liliana Marcela Henao Muñoz

    2015-03-01

    Full Text Available Glyphosate is the most widely used herbicide in the world with application in agriculture, forestry, industrial weed control, garden and aquatic environments. However, its use is highly controversial for the possible impact on not-target organisms, such as amphibians, which are vanishing at an alarming and rapid rate. Due to the high solubility in water and ionic nature, the glyphosate requires of surfactants to increase activity. In addition, for the control of coca (Erythroxylum coca and agricultural weeds in Colombia, formulated glyphosate is mixed and sprayed with the adjuvant Cosmo-Flux®411F to increase the penetration and activity of the herbicide. This study evaluates the acute toxic and sublethal effects (embryonic development, tadpole body size, tadpole swimming performance of the mixture of the formulated glyphosate Roundup® Active and Cosmo-Flux®411F to anuran embryos and tadpoles of four Colombian species under 96h laboratory standard tests and microcosms, which are more similar to field conditions as they include soil, sand and macrophytes. In the laboratory, embryos and tadpoles of Engystomops pustulosus were the most tolerant (LC50=3 904µg a.e./L; LC50=2 799µg a.e./L, respectively, while embryos and tadpoles of Hypsiboas crepitans (LC50=2 203µg a.e./L; LC50=1 424µg a.e./L, respectively were the most sensitive. R. humboldti and R. marina presented an intermediate toxicity. Embryos were significantly more tolerant to the mixture than tadpoles, which could be likely attributed to the exclusion of chemicals by the embryonic membranes and the lack of organs, such as gills, which are sensitive to surfactants. Sublethal effects were observed for the tadpole body size, but not for the embryonic development and tadpole swimming performance. In microcosms, no toxicity (LC50 could not be estimated, or sublethal responses were observed at concentrations up to fourfold (14.76kg glyphosate a.e./ha the highest field application rate of 3

  1. Geomorphology and forest management in New Zealand's erodible steeplands: An overview

    Science.gov (United States)

    Phillips, Chris; Marden, Michael; Basher, Les R.

    2018-04-01

    In this paper we outline how geomorphological understanding has underpinned forest management in New Zealand's erodible steeplands, where it contributes to current forest management, and suggest where it will be of value in the future. We focus on the highly erodible soft-rock hill country of the East Coast region of North Island, but cover other parts of New Zealand where appropriate. We conclude that forestry will continue to make a significant contribution to New Zealand's economy, but several issues need to be addressed. The most pressing concerns are the incidence of post-harvest, storm-initiated landslides and debris flows arising from steepland forests following timber harvesting. There are three areas where geomorphological information and understanding are required to support the forest industry - development of an improved national erosion susceptibility classification to support a new national standard for plantation forestry; terrain analysis to support improved hazard and risk assessment at detailed operational scales; and understanding of post-harvest shallow landslide-debris flows, including their prediction and management.

  2. Influence of biochar and terra preta substrates on wettability and erodibility of soils

    Science.gov (United States)

    Smetanova, A.; Dotterweich, M.; Diehl, D.; Ulrich, U.; Fohrer, N.

    2012-04-01

    Biochar (BC) and terra preta substrates (TPS) have recently been promoted as soil amendments suitable for soil stabilization, soil amelioration and long-term carbon sequestration. BC is a carbon-enriched substance produced by thermal decomposition of organic material. TPS is composed of liquid and solid organic matter, including BC, altered by acid-lactic fermentation. Their effect on wettability, soil erodibility and nutrient discharge through overland flow was studied by laboratory experiments. At water contents between 0 and 100% BC is water repellent, while TPS changes from a wettable into a repellent state. The 5 and 10 vol % mixtures of BC and 10 and 20 vol% mixtures of TPS with sand remain mainly wettable during drying but repellency maxima are shifted to higher water contents with respect to pure sand and are mainly of subcritical nature. The runoff response was dominated by infiltration properties of the substrates rather than their wettability.Only one mixtures (20% TPS) produced more runoff than sandy-loamy soil on a 15% slope at an intensity of 25 mm•h-1. The 10% BC decreased runoff by up to 40%. At higher rainfall intensities (45 and 55 mm•h-1) the 10% TPS7 was up to 35% less erodible than 10% BC. Despite the TPS containing more nutrients, nutrient discharge varied between types of nutrients, slopes, rainfall intensities and mixtures. The application of a 1 cm layer onto the soil surface instead of 10% mixtures is not recommended due to high nutrient concentrations in the runoff and the wettability of pure substrates. The usage of 10% BC in lowland areas with low frequency and low-intensity precipitation and 10% TPS7 in areas with higher rainfall intensities appears to be appropriate and commendable according to current results. However, together with reversibility of repellency, it needs to undergo further examination in the field under different environmental and land use conditions Key words: biochar, terra preta substrate, wettability

  3. Effects of in vivo chronic exposure to pendimethalin on EROD activity and antioxidant defenses in rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Danion, Morgane; Le Floch, Stéphane; Lamour, François; Quentel, Claire

    2014-01-01

    Pendimethalin, an herbicide active substance frequently used in terrestrial systems, has detected in European aquatic ecosystems. Reliable indicators still need to be found in order to properly assess the impact of pesticides in fish. After an in vivo chronic exposure to pendimethalin, the detoxification process and the antioxidant defense system were assessed in 120 adult rainbow trout, Oncorhynchus mykiss. Four nominal exposure conditions were tested: control (C), 500 ng L(-1) (P500), 800 ng L(-1) (P800) and the commercial formulation Prowl(®) at 500 ng L(-1) (Pw500). Fish samples were made after a 28 day exposure period (D28) and after a fifteen day recovery period in clean fresh water (D43). At D28, ethoxyresorufin-O-deethylase (EROD) activity was not activated in liver in spite of the pendimethalin uptake in fish. At D43, EROD activity in fish exposed to the commercial product was lower than in control fish, which may be explained by the high presence of herbicide in fish (613±163 ng g bile(-1)). Furthermore, antioxidant defense responses were set up by trout in gills and liver following chronic exposure to 800 ng L(-1) of pendimethalin concentration. While the glutathione content (GSH) decreased in gills, it increased in liver associated with higher activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD). These disturbances could lead to reactive oxygen species production and oxidative stress in the vital organs in fish. After fifteen days in clean water, while the SOD activity was restored, the GSH content and GPx activity were still significantly disturbed in fish exposed to pendimethalin in comparison with control. These significant differences between treatments in antioxidant defenses parameters measured, attesting to the irreversibility of the effects. © 2013 Published by Elsevier Inc.

  4. Occurrence of sublethal injury after pulsed electric fields depending on the micro-organism, the treatment medium ph and the intensity of the treatment investigated.

    Science.gov (United States)

    García, D; Gómez, N; Mañas, P; Condón, S; Raso, J; Pagán, R

    2005-01-01

    The objective was to investigate the occurrence of sublethal injury after pulsed electric field (PEF) depending on the treatment time, the electric field strength and the pH of the treatment media in two Gram-positive (Bacillus subtilis ssp. niger, Listeria monocytogenes) and six Gram-negative (Escherichia coli, Escherichia coli O157:H7, Pseudomonas aeruginosa, Salmonella serotype Senftenberg 775W, Salmonella serotype Typhimurium, Yersinia enterocolitica) bacterial strains. A characteristic behaviour was observed for the Gram-positive and Gram-negative bacteria studied. Whereas Gram-positive bacteria showed a higher PEF resistance at pH 7.0, the Gram-negative were more resistant at pH 4.0. In these conditions, in which bacteria showed their maximum resistance, a large proportion of sublethally injured cells were detected. In most cases, the longer the treatment time and the higher the electric field applied, the greater the proportion of sublethally injured cells that were detected. No sublethal injury was detected when Gram-positive bacteria were treated at pH 4.0 and Gram-negative at pH 7.0. Sublethal injury was detected after PEF so, bacterial inactivation by PEF is not an 'all or nothing' event. This work could be useful for improving food preservation by PEF.

  5. Effects of Sub-lethal Concentrations of Silver Nanoparticles on a Simulated Intestinal Prokaryotic–Eukaryotic Interface

    Directory of Open Access Journals (Sweden)

    Elisa Garuglieri

    2018-01-01

    Full Text Available Nanotechnology applications are expected to bring a range of benefits to the food sector, aiming to provide better quality and conservation. In this research, the physiological response of both an Escherichia coli mono-species biofilm and Caco-2 intestinal cells to sub-lethal concentrations of silver nanoparticles (AgNPs has been investigated. In order to simulate the anaerobic and aerobic compartments required for bacteria and intestinal cells growth, a simplified semi-batch model based on a transwell permeable support was developed. Interaction between the two compartments was obtained by exposing Caco-2 intestinal cells to the metabolites secreted by E. coli biofilm after its exposure to AgNPs. To the best of the authors’ knowledge, this study is the first to investigate the effect of AgNPs on Caco-2 cells that takes into consideration previous AgNP-intestinal biofilm interactions, and at concentrations mimicking real human exposure. Our data show that 1 μg/mL AgNPs in anaerobic conditions (i promote biofilm formation up to 2.3 ± 0.3 fold in the first 72 h of treatment; (ii increase reactive oxygen species (ROS production to 84 ± 21% and change the physiological status of microbial cells after 96 h of treatment; (iii seriously affect a 72-h old established biofilm, increasing the level of oxidative stress to 86 ± 21%. Moreover, the results indicate that oxygen renders the biofilm more adequate to counteract AgNP effects. Comet assays on Caco-2 cells demonstrated a protective role of biofilm against the genotoxic effect of 1 μg/mL AgNPs on intestinal epithelial cells.

  6. Response of sublethally irradiated monkeys to a replicating viral antigen

    International Nuclear Information System (INIS)

    Hilmas, D.E.; Spertzel, R.O.

    1975-01-01

    Temporal effects of exposure to sublethal, total-body x radiation (400 R) on responses to vaccination with the attenuated Venezuelan equine encephalomyelitis vaccine virus, TC-83, were examined in rhesus monkeys. Viremia, often with delayed onset, was prolonged even when irradiation preceded vaccination by 28 days. Virus titers were increased, particularly in groups irradiated 4 or 7 days before vaccination. Delay in appearance of hemagglutination-inhibition and serum-neutralizing antibody correlated closely with persistence of viremia in irradiated-vaccinated monkeys. The temporal course of antibody response was markedly affected by the interval between irradiation and injection of this replicating antigen. With longer intervals between irradiation and vaccination, the somewhat depressed antibody responses approached normal or surpassed those of nonirradiated monkeys. Vaccination 14 days after radiation exposure resulted in lethality to 8 of 12 monkeys, apparently as a result of secondary infection. The additional lymphopenic stress due to the effect of TC-83, superimposed on the severely depressed hematopoietic competence at 14 days, undoubtedly contributed to this increased susceptibility to latent infection

  7. Chloride and sulphate toxicity to Hydropsyche exocellata (Trichoptera, Hydropsychidae): Exploring intraspecific variation and sub-lethal endpoints

    Energy Technology Data Exchange (ETDEWEB)

    Sala, Miquel [Centre Tecnològic Forestal de Catalunya - CTFC, Solsona, Catalunya (Spain); Faria, Melissa [CESAM, Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Sarasúa, Ignacio [Technische Universität München, Munich, Bayern (Germany); Barata, Carlos [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona (Spain); Bonada, Núria [Grup de Recerca Freshwater Ecology and Management (FEM), Departament d' Ecologia, Facultat de Biologia, Universitat de Barcelona (UB), Diagonal 643, 08028 Barcelona, Catalonia (Spain); Grup de Recerca Freshwater Ecology and Management (FEM), Departament d' Ecologia, Facultat de Biologia, Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona - UB, Diagonal 643, 08028 Barcelona, Catalonia (Spain); Brucet, Sandra [Aquatic Ecology Group, BETA Tecnio Centre, University of Vic - Central University of Catalonia, Vic, Catalonia (Spain); Catalan Institution for Research and Advanced Studies, ICREA, Barcelona 08010 (Spain); Llenas, Laia; Ponsá, Sergio [Aquatic Ecology Group, BETA Tecnio Centre, University of Vic - Central University of Catalonia, Vic, Catalonia (Spain); Prat, Narcís [Grup de Recerca Freshwater Ecology and Management (FEM), Departament d' Ecologia, Facultat de Biologia, Universitat de Barcelona (UB), Diagonal 643, 08028 Barcelona, Catalonia (Spain); Soares, Amadeu M.V.M. [CESAM, Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); and others

    2016-10-01

    The rivers and streams of the world are becoming saltier due to human activities. In spite of the potential damage that salt pollution can cause on freshwater ecosystems, this is an issue that is currently poorly managed. Here we explored intraspecific differences in the sensitivity of freshwater fauna to two major ions (Cl{sup −} and SO{sub 4}{sup 2−}) using the net-spinning caddisfly Hydropsyche exocellata Dufour 1841 (Trichoptera, Hydropsychidae) as a model organism. We exposed H. exocellata to saline solutions (reaching a conductivity of 2.5 mS cm{sup −1}) with Cl{sup −}:SO{sub 4}{sup 2−} ratios similar to those occurring in effluents coming from the meat, mining and paper industries, which release dissolved salts to rivers and streams in Spain. We used two different populations, coming from low and high conductivity streams. To assess toxicity, we measured sub-lethal endpoints: locomotion, symmetry of the food-capturing nets and oxidative stress biomarkers. According to biomarkers and net building, the population historically exposed to lower conductivities (B10) showed higher levels of stress than the population historically exposed to higher conductivities (L102). However, the differences between populations were not strong. For example, net symmetry was lower in the B10 than in the L102 only 48 h after treatment was applied, and biomarkers showed a variety of responses, with no discernable pattern. Also, treatment effects were rather weak, i.e. only some endpoints, and in most cases only in the B10 population, showed a significant response to treatment. The lack of consistent differences between populations and treatments could be related to the high salt tolerance of H. exocellata, since both populations were collected from streams with relatively high conductivities. The sub-lethal effects tested in this study can offer an interesting and promising tool to monitor freshwater salinization by combining physiological and behavioural bioindicators

  8. Chloride and sulphate toxicity to Hydropsyche exocellata (Trichoptera, Hydropsychidae): Exploring intraspecific variation and sub-lethal endpoints

    International Nuclear Information System (INIS)

    Sala, Miquel; Faria, Melissa; Sarasúa, Ignacio; Barata, Carlos; Bonada, Núria; Brucet, Sandra; Llenas, Laia; Ponsá, Sergio; Prat, Narcís; Soares, Amadeu M.V.M.

    2016-01-01

    The rivers and streams of the world are becoming saltier due to human activities. In spite of the potential damage that salt pollution can cause on freshwater ecosystems, this is an issue that is currently poorly managed. Here we explored intraspecific differences in the sensitivity of freshwater fauna to two major ions (Cl"− and SO_4"2"−) using the net-spinning caddisfly Hydropsyche exocellata Dufour 1841 (Trichoptera, Hydropsychidae) as a model organism. We exposed H. exocellata to saline solutions (reaching a conductivity of 2.5 mS cm"−"1) with Cl"−:SO_4"2"− ratios similar to those occurring in effluents coming from the meat, mining and paper industries, which release dissolved salts to rivers and streams in Spain. We used two different populations, coming from low and high conductivity streams. To assess toxicity, we measured sub-lethal endpoints: locomotion, symmetry of the food-capturing nets and oxidative stress biomarkers. According to biomarkers and net building, the population historically exposed to lower conductivities (B10) showed higher levels of stress than the population historically exposed to higher conductivities (L102). However, the differences between populations were not strong. For example, net symmetry was lower in the B10 than in the L102 only 48 h after treatment was applied, and biomarkers showed a variety of responses, with no discernable pattern. Also, treatment effects were rather weak, i.e. only some endpoints, and in most cases only in the B10 population, showed a significant response to treatment. The lack of consistent differences between populations and treatments could be related to the high salt tolerance of H. exocellata, since both populations were collected from streams with relatively high conductivities. The sub-lethal effects tested in this study can offer an interesting and promising tool to monitor freshwater salinization by combining physiological and behavioural bioindicators. - Highlights: • We assessed Cl

  9. Acute and sub-lethal exposure to copper oxide nanoparticles causes oxidative stress and teratogenicity in zebrafish embryos.

    Science.gov (United States)

    Ganesan, Santhanamari; Anaimalai Thirumurthi, Naveenkumar; Raghunath, Azhwar; Vijayakumar, Savitha; Perumal, Ekambaram

    2016-04-01

    Nano-copper oxides are a versatile inorganic material. As a result of their versatility, the immense applications and usage end up in the environment causing a concern for the lifespan of various beings. The ambiguities surround globally on the toxic effects of copper oxide nanoparticles (CuO-NPs). Hence, the present study endeavored to study the sub-lethal acute exposure effects on the developing zebrafish embryos. The 48 hpf LC50 value was about 64 ppm. Therefore, we have chosen the sub-lethal dose of 40 and 60 ppm for the study. Accumulation of CuO-NPs was evidenced from the SEM-EDS and AAS analyzes. The alterations in the AChE and Na(+)/K(+)-ATPase activities disrupted the development process. An increment in the levels of oxidants with a concomitant decrease in the antioxidant enzymes confirmed the induction of oxidative stress. Oxidative stress triggered apoptosis in the exposed embryos. Developmental anomalies were observed with CuO-NPs exposure in addition to oxidative stress in the developing embryos. Decreased heart rate and hatching delay hindered the normal developmental processes. Our work has offered valuable data on the connection between oxidative stress and teratogenicity leading to lethality caused by CuO-NPs. A further molecular mechanism unraveling the uncharted connection between oxidative stress and teratogenicity will aid in the safe use of CuO-NPs. Copyright © 2015 John Wiley & Sons, Ltd.

  10. [Characteristics of Soil Respiration along Eroded Sloping Land with Different SOC Background on the Hilly Loess Plateau].

    Science.gov (United States)

    Chen, Gai; Xu, Ming-xiang; Zhang, Ya-feng; Wang, Chao-hua; Fan, Hui-min; Wang, Shan-shan

    2015-09-01

    This study aimed to characterize soil respiration along eroded sloping land at erosion and deposition area under different soil organic carbon(SOC) levels, and linked the relationship between soil respiration and soil temperature, soil moisture, SOC and slope position. Experiments were carried out in the plots of S type slopes include five different soil organic carbon levels in the Loess Hilly Region. The S type slopes were divided into control area at the top of the slope, erosion area at the middle of the slope and deposition area at the toe of the slope. We found that soil temperature had a greater impact on soil respiration in the deposition area, whereas soil moisture had a greater impact on soil respiration in the erosion area compared among control area, erosion area and deposition area. In addition, SOC was the most important factor affecting soil respiration, which can explain soil respiration variation 54. 72%, followed by soil moisture, slope position and soil temperature, which explain soil respiration variation 18. 86% , 16. 13% and 10. 29%, respectively. Soil respiration response to erosion showed obvious on-site and off-site effects along the eroded sloping land. Soil respiration in the erosion area was reduced by 21. 14% compared with control area, and soil respiration in the deposition area was increased by 21. 93% compared with control area. Erosion effect on source and sink of carbon emission was correlated with SOC content of the eroded sloping land. When SOC content was higher than 6. 82 g.kg-1, the slope. erosion tended to be a carbon sequestration process, and when SOC content was lower than 3.03 g.kg-1, the slope erosion tended to be a process of the carbon emission source. The model could reflect the relationship between soil respiration and independent variables of soil organic carbon content, soil temperature and moisture.

  11. Sub ablative Er: YAG laser irradiation on surface roughness of eroded dental enamel.

    Science.gov (United States)

    Curylofo-Zotti, Fabiana Almeida; Lepri, Taísa Penazzo; Colucci, Vivian; Turssi, Cecília Pedroso; Corona, Silmara Aparecida Milori

    2015-11-01

    This study evaluated the effects of Er:YAG laser irradiation applied at varying pulse repetition rate on the surface roughness of eroded enamel. Bovine enamel slabs (n = 10) were embedded in polyester resin, ground, and polished. To erosive challenges, specimens were immersed two times per day in 20mL of concentrated orange juice (pH = 3.84) under agitation, during a two-day period. Specimens were randomly assigned to irradiation with the Er:YAG laser (focused mode, pulse energy of 60 mJ and energy density of 3.79 J/cm(2) ) operating at 1, 2, 3, or 4 Hz. The control group was left nonirradiated. Surface roughness measurements were recorded post erosion-like formation and further erosive episodes by a profilometer and observed through atomic force microscopy (AFM). Analysis of variance revealed that the control group showed the lowest surface roughness, while laser-irradiated substrates did not differ from each other following post erosion-like lesion formation. According to analysis of covariance, at further erosive episodes, the control group demonstrated lower surface roughness (P > 0.05), than any of the irradiated groups (P enamel eroded. The AFM images showed that the specimens irradiated by the Er:YAG laser at 1 Hz presented a less rough surface than those irradiated at 2, 3, and 4 Hz. © 2015 Wiley Periodicals, Inc.

  12. Effects of sub-lethal high-pressure homogenization treatment on the outermost cellular structures and the volatile-molecule profiles of two strains of probiotic lactobacilli.

    Science.gov (United States)

    Tabanelli, Giulia; Vernocchi, Pamela; Patrignani, Francesca; Del Chierico, Federica; Putignani, Lorenza; Vinderola, Gabriel; Reinheimer, Jorge A; Gardini, Fausto; Lanciotti, Rosalba

    2015-01-01

    Applying sub-lethal levels of high-pressure homogenization (HPH) to lactic acid bacteria has been proposed as a method of enhancing some of their functional properties. Because the principal targets of HPH are the cell-surface structures, the aim of this study was to examine the effect of sub-lethal HPH treatment on the outermost cellular structures and the proteomic profiles of two known probiotic bacterial strains. Moreover, the effect of HPH treatment on the metabolism of probiotic cells within a dairy product during its refrigerated storage was investigated using SPME-GC-MS. Transmission electron microscopy was used to examine the microstructural changes in the outermost cellular structures due to HPH treatment. These alterations may be involved in the changes in some of the technological and functional properties of the strains that were observed after pressure treatment. Moreover, the proteomic profiles of the probiotic strains treated with HPH and incubated at 37°C for various periods showed different peptide patterns compared with those of the untreated cells. In addition, there were differences in the peaks that were observed in the low-mass spectral region (2000-3000 Da) of the spectral profiles of the control and treated samples. Due to pressure treatment, the volatile-molecule profiles of buttermilk inoculated with treated or control cells and stored at 4°C for 30 days exhibited overall changes in the aroma profile and in the production of molecules that improved its sensory profile, although the two different species imparted specific fingerprints to the product. The results of this study will contribute to understanding the changes that occur in the outermost cellular structures and the metabolism of LAB in response to HPH treatment. The findings of this investigation may contribute to elucidating the relationships between these changes and the alterations of the technological and functional properties of LAB induced by pressure treatment.

  13. Glyphosate and AMPA distribution in wind-eroded sediment derived from loess soil

    NARCIS (Netherlands)

    Martins Bento, Celia; Goossens, Dirk; Rezaei, Mahrooz; Riksen, M.J.P.M.; Mol, J.G.J.; Ritsema, C.J.; Geissen, V.

    2017-01-01

    Glyphosate is one of the most used herbicides in agricultural lands worldwide. Wind-eroded sediment and dust, as an environmental transport pathway of glyphosate and of its main metabolite aminomethylphosphonic acid (AMPA), can result in environmental- and human exposure far beyond the agricultural

  14. Sublethal doses of neonicotinoid imidacloprid can interact with honey bee chemosensory protein 1 (CSP1) and inhibit its function

    International Nuclear Information System (INIS)

    Li, Hongliang; Tan, Jing; Song, Xinmi; Wu, Fan; Tang, Mingzhu; Hua, Qiyun; Zheng, Huoqing; Hu, Fuliang

    2017-01-01

    As a frequently used neonicotinoid insecticide, imidacloprid can impair the chemoreceptive behavior of honey bees even at sublethal doses, while the physiochemical mechanism has not been further revealed. Here, multiple fluorescence spectra, thermodynamic method, and molecular docking were used to study the interaction and the functional inhibition of imidacloprid to the recombinant CSP1 protein in Asian honey bee, Apis cerana. The results showed that the fluorescence intensity (λ em  = 332 nm) of CSP1 could be significantly quenched by imidacloprid in a dynamic mode. During the quenching process, ΔH > 0, ΔS > 0, indicating that the acting forces of imidacloprid with CSP1 are mainly hydrophobic interactions. Synchronous fluorescence showed that the fluorescence of CSP1 was mainly derived from tryptophan, and the hydrophobicity of tryptophan decreased with the increase of imidacloprid concentration. Molecular docking predicted the optimal pose and the amino acid composition of the binding process. Circular dichroism (CD) spectra showed that imidacloprid reduced the α-helix of CSP1 and caused the extension of the CSP1 peptide chain. In addition, the binding of CSP1 to floral scent β-ionone was inhibited by nearly 50% of the apparent association constant (K A ) in the presence of 0.28–2.53 ng/bee of imidacloprid, and the inhibition rate of nearly 95% at 3.75 ng/bee of imidacloprid at sublethal dose level. This study initially revealed the molecular physiochemical mechanism that sublethal doses of neonicotinoid still interact and inhibit the physiological function of the honey bees' chemoreceptive system. - Highlights: • Sublethal doses of imidacloprid can directly interact with CSP1 in Apis cerana. • Sublethal imidacloprid can inhibit the function of CSP1 binding to semiochemicals. • The fluorescence intensity of CSP1 quenched by imidacloprid in a dynamic mode. • The binding between CSP1 and imidacloprid are driven by hydrophobic interactions.

  15. Changes in liver glycogen reserve in Wistar rats as a result of polysaccharide treatment and single sublethal gamma-irradiation

    International Nuclear Information System (INIS)

    Metodiev, S.; Lambov, V.; Pavlova, N.

    1993-01-01

    The phase changes in the quantity of liver glycogen after single sublethal irradiation are investigated. The lowest concentration levels are registered at days 1, 3, 8 and 13 post irradiation. The effect of polysaccharide radioresistance modulation on the liver glycogen concentration is evaluated. The subcutaneous polysaccharide application of the immuno-active product PL prevents the sharp decrease of the liver glycogen concentration level, as a result of radiation provoked damages. The polysaccharide protection is most effective 5 - 21 days after irradiation. The conclusions are based on enzymic and hystomorphological studies. (author)

  16. Formation of Staphylococcus aureus Biofilm in the Presence of Sublethal Concentrations of Disinfectants Studied via a Transcriptomic Analysis Using Transcriptome Sequencing (RNA-seq)

    Science.gov (United States)

    Oppelt, J.; Cincarova, L.

    2017-01-01

    ABSTRACT Staphylococcus aureus is a common biofilm-forming pathogen. Low doses of disinfectants have previously been reported to promote biofilm formation and to increase virulence. The aim of this study was to use transcriptome sequencing (RNA-seq) analysis to investigate global transcriptional changes in S. aureus in response to sublethal concentrations of the commonly used food industry disinfectants ethanol (EtOH) and chloramine T (ChT) and their combination (EtOH_ChT) in order to better understand the effects of these agents on biofilm formation. Treatment with EtOH and EtOH_ChT resulted in more significantly altered expression profiles than treatment with ChT. Our results revealed that EtOH and EtOH_ChT treatments enhanced the expression of genes responsible for regulation of gene expression (sigB), cell surface factors (clfAB), adhesins (sdrDE), and capsular polysaccharides (cap8EFGL), resulting in more intact biofilm. In addition, in this study we were able to identify the pathways involved in the adaptation of S. aureus to the stress of ChT treatment. Further, EtOH suppressed the effect of ChT on gene expression when these agents were used together at sublethal concentrations. These data show that in the presence of sublethal concentrations of tested disinfectants, S. aureus cells trigger protective mechanisms and try to cope with them. IMPORTANCE So far, the effect of disinfectants is not satisfactorily explained. The presented data will allow a better understanding of the mode of disinfectant action with regard to biofilm formation and the ability of bacteria to survive the treatment. Such an understanding could contribute to the effort to eliminate possible sources of bacteria, making disinfectant application as efficient as possible. Biofilm formation plays significant role in the spread and pathogenesis of bacterial species. PMID:29030437

  17. Sublethal red tide toxin exposure in free-ranging manatees (Trichechus manatus) affects the immune system through reduced lymphocyte proliferation responses, inflammation, and oxidative stress

    International Nuclear Information System (INIS)

    Walsh, Catherine J.; Butawan, Matthew; Yordy, Jennifer; Ball, Ray; Flewelling, Leanne; Wit, Martine de; Bonde, Robert K.

    2015-01-01

    Highlights: • Sublethal brevetoxin exposure affects manatee immune function. • Plasma brevetoxin levels correlate with oxidative stress in rescued manatees. • Brevetoxin exposure affects lymphocyte proliferation in rescued manatees. • Plasma brevetoxin concentrations ranged from 0 to 19 ng PbTx-3 eq/mL. - Abstract: The health of many Florida manatees (Trichechus manatus latirostris) is adversely affected by exposure to blooms of the toxic dinoflagellate, Karenia brevis. K. brevis blooms are common in manatee habitats of Florida’s southwestern coast and produce a group of cyclic polyether toxins collectively referred to as red tide toxins, or brevetoxins. Although a large number of manatees exposed to significant levels of red tide toxins die, several manatees are rescued from sublethal exposure and are successfully treated and returned to the wild. Sublethal brevetoxin exposure may potentially impact the manatee immune system. Lymphocyte proliferative responses and a suite of immune function parameters in the plasma were used to evaluate effects of brevetoxin exposure on health of manatees rescued from natural exposure to red tide toxins in their habitat. Blood samples were collected from rescued manatees at Lowry Park Zoo in Tampa, FL and from healthy, unexposed manatees in Crystal River, FL. Peripheral blood leukocytes (PBL) isolated from whole blood were stimulated with T-cell mitogens, ConA and PHA. A suite of plasma parameters, including plasma protein electrophoresis profiles, lysozyme activity, superoxide dismutase (SOD) activity, and reactive oxygen/nitrogen (ROS/RNS) species, was also used to assess manatee health. Significant decreases (p < 0.05) in lymphocyte proliferation were observed in ConA and PHA stimulated lymphocytes from rescued animals compared to non-exposed animals. Significant correlations were observed between oxidative stress markers (SOD, ROS/RNS) and plasma brevetoxin concentrations. Sublethal exposure to brevetoxins in the

  18. Sublethal red tide toxin exposure in free-ranging manatees (Trichechus manatus) affects the immune system through reduced lymphocyte proliferation responses, inflammation, and oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Catherine J., E-mail: cjwalsh@mote.org [Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236 (United States); Butawan, Matthew, E-mail: mattbutawan@outlook.com [Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236 (United States); Yordy, Jennifer, E-mail: jennifer.e.balmer@gmail.com [Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236 (United States); Ball, Ray, E-mail: Ray.Ball@lowryparkzoo.com [Lowry Park Zoo, 1101 W Sligh Ave, Tampa, FL 33604 (United States); Flewelling, Leanne, E-mail: Leanne.Flewelling@MyFWC.com [Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, 100 8th Ave SE, St. Petersburg, FL 33701 (United States); Wit, Martine de, E-mail: Martine.deWit@MyFWC.com [Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, 100 8th Ave SE, St. Petersburg, FL 33701 (United States); Bonde, Robert K., E-mail: rbonde@usgs.gov [U.S. Geological Survey, Sirenia Project, 7920 NE 71st Street, Gainesville, FL 32653 (United States)

    2015-04-15

    Highlights: • Sublethal brevetoxin exposure affects manatee immune function. • Plasma brevetoxin levels correlate with oxidative stress in rescued manatees. • Brevetoxin exposure affects lymphocyte proliferation in rescued manatees. • Plasma brevetoxin concentrations ranged from 0 to 19 ng PbTx-3 eq/mL. - Abstract: The health of many Florida manatees (Trichechus manatus latirostris) is adversely affected by exposure to blooms of the toxic dinoflagellate, Karenia brevis. K. brevis blooms are common in manatee habitats of Florida’s southwestern coast and produce a group of cyclic polyether toxins collectively referred to as red tide toxins, or brevetoxins. Although a large number of manatees exposed to significant levels of red tide toxins die, several manatees are rescued from sublethal exposure and are successfully treated and returned to the wild. Sublethal brevetoxin exposure may potentially impact the manatee immune system. Lymphocyte proliferative responses and a suite of immune function parameters in the plasma were used to evaluate effects of brevetoxin exposure on health of manatees rescued from natural exposure to red tide toxins in their habitat. Blood samples were collected from rescued manatees at Lowry Park Zoo in Tampa, FL and from healthy, unexposed manatees in Crystal River, FL. Peripheral blood leukocytes (PBL) isolated from whole blood were stimulated with T-cell mitogens, ConA and PHA. A suite of plasma parameters, including plasma protein electrophoresis profiles, lysozyme activity, superoxide dismutase (SOD) activity, and reactive oxygen/nitrogen (ROS/RNS) species, was also used to assess manatee health. Significant decreases (p < 0.05) in lymphocyte proliferation were observed in ConA and PHA stimulated lymphocytes from rescued animals compared to non-exposed animals. Significant correlations were observed between oxidative stress markers (SOD, ROS/RNS) and plasma brevetoxin concentrations. Sublethal exposure to brevetoxins in the

  19. Morphology of ductile metals eroded by a jet of spherical particles impinging at normal incidence

    Science.gov (United States)

    Veerabhadra Rao, P.; Young, S. G.; Buckley, D. H.

    1983-01-01

    Scanning electron microscopy and energy-dispersive X-ray spectroscopy are used, together with surface profile measurements, in the present morphological study of the erosion of an aluminum alloy and copper by the normal impact of spherical glass erodent particles. The morphology of the damage pattern is a manifestation of the flow pattern of erodent particles, and yields insight into the mechanisms that may be active at different stages of erosion. The simultaneous appearance of radial cracks and concentric rings is reported, together with wave crests which contain an accumulation of metallic flakes. A preliminary analysis is advanced to explain the formation of the various damage patterns observed.

  20. Sublethal Effects of Beauveria bassiana (Ascomycota: Hypocreales) on Life Table Parameters of Frankliniella occidentalis (Thysanoptera: Thripidae).

    Science.gov (United States)

    Zhang, Tao; Reitz, Stuart R; Wang, Haihong; Lei, Zhongren

    2015-06-01

    We assessed effects of parental exposure to Beauveria bassiana on life history traits of subsequent generations of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Progeny from individuals that survived fungal exposure as second instars had significantly shorter egg stages, but longer prepupal development times than corresponding untreated controls. However, survivorship to adulthood of these progeny groups did not differ. Although fecundities of the parental types did not differ, the sex ratio of progeny from fungal-treated parents was male-biased, whereas sex ratio of progeny from untreated control parents was even. We calculated life table parameters for the progeny and found that all parameters, except for generation time, were significantly less for the progeny of fungal-treated parents than for progeny of untreated parents. The intrinsic rate of increase, finite rate of increase, net reproductive rate, mean generation time, and gross reproductive rate were 0.199 d(-1), 1.229 d(-1), 21.84, 15.48 d, and 27.273, respectively, for progeny of treated thrips, and 0.266 d(-1), 1.316 d(-1), 52.540, 14.92 d, and 70.64, respectively, for progeny of control thrips. Consequently, population projections demonstrated that offspring of parents exposed to B. bassiana would increase their population more slowly than those from untreated parents. These results demonstrate that B. bassiana has sublethal effects that reduce the reproductive success of F. occidentalis and these effects should be taken into account when evaluating its use in management programs for F. occidentalis. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Exposure to sublethal concentrations of tributyltin reduced survival, growth, and 20-hydroxyecdysone levels in a marine mysid.

    Science.gov (United States)

    Kim, Bo-Mi; Saravanan, Manoharan; Lee, Do-Hee; Kang, Jung-Hoon; Kim, Moonkoo; Jung, Jee-Hyun; Rhee, Jae-Sung

    2018-06-07

    Tributyltin (TBT) is as an antifouling organotin compound used in boat paints. Although organotin-based antifouling agents have been banned on a global scale, the mode of action of TBT has been studied in numerous aquatic species because of its toxicity, persistence, bioaccumulation potential, and endocrine-disrupting characteristics. In this study, we conducted 96-h acute toxicity tests wherein we exposed juvenile and adult marine mysids to waterborne TBT. Over 4 weeks of exposure, mortality was dose-dependently increased in juveniles and adult mysids. To test sublethal effects of TBT on juvenile development, newborn juvenile mysids were exposed to 1, 5, or 10 ng L -1  TBT for 4 weeks. Subsequently, we measured morphological growth parameters and quantified the hormone ecdysterone (20-hydroxyecdysone: 20E), which controls molting in mysids. The lengths of the whole body, antennal scale, exopod, endopod, and telson were significantly smaller in the 5 and/or 10 ng L -1 TBT-exposed juvenile mysids than in control and DMSO-exposed groups. Levels of 20E were significantly lower at 5 and 10 ng L -1  TBT exposures. Additionally, the number of newly hatched juveniles was significantly lower from females previously exposed to 10 ng L -1  TBT. Our results indicate sublethal concentrations of TBT have inhibitory effects on the survival, growth, and production of juveniles. The lower 20E levels could be strongly associated with TBT-triggered inhibition. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Sublethal Concentrations of Carbapenems Alter Cell Morphology and Genomic Expression of Klebsiella pneumoniae Biofilms

    Science.gov (United States)

    Van Laar, Tricia A.; Chen, Tsute; You, Tao

    2015-01-01

    Klebsiella pneumoniae, a Gram-negative bacterium, is normally associated with pneumonia in patients with weakened immune systems. However, it is also a prevalent nosocomial infectious agent that can be found in infected surgical sites and combat wounds. Many of these clinical strains display multidrug resistance. We have worked with a clinical strain of K. pneumoniae that was initially isolated from a wound of an injured soldier. This strain demonstrated resistance to many commonly used antibiotics but sensitivity to carbapenems. This isolate was capable of forming biofilms in vitro, contributing to its increased antibiotic resistance and impaired clearance. We were interested in determining how sublethal concentrations of carbapenem treatment specifically affect K. pneumoniae biofilms both in morphology and in genomic expression. Scanning electron microscopy showed striking morphological differences between untreated and treated biofilms, including rounding, blebbing, and dimpling of treated cells. Comparative transcriptome analysis using RNA sequencing (RNA-Seq) technology identified a large number of open reading frames (ORFs) differentially regulated in response to carbapenem treatment at 2 and 24 h. ORFs upregulated with carbapenem treatment included genes involved in resistance, as well as those coding for antiporters and autoinducers. ORFs downregulated included those coding for metal transporters, membrane biosynthesis proteins, and motility proteins. Quantitative real-time PCR validated the general trend of some of these differentially regulated ORFs. Treatment of K. pneumoniae biofilms with sublethal concentrations of carbapenems induced a wide range of phenotypic and gene expression changes. This study reveals some of the mechanisms underlying how sublethal amounts of carbapenems could affect the overall fitness and pathogenic potential of K. pneumoniae biofilm cells. PMID:25583711

  3. Therapeutic use of recombinant human G-CSF (rhG-CSF) in a canine model of sublethal and lethal whole-body irradiation

    International Nuclear Information System (INIS)

    MacVittie, T.J.; Monroy, R.L.; Patchen, M.L.; Souza, L.M.

    1990-01-01

    Recombinant human G-CSF (rhG-CSF) was studied for its ability to modulate haemopoiesis in normal dogs as well as to decrease therapeutically the severity and duration of neutropenia in sublethally and lethally irradiated dogs. Data indicate that in the lethally irradiated dog, effective cytokine therapy with rhG-CSF will increase survival through the induction of earlier recovery of neutrophils and platelets. (author)

  4. Recovery from sublethal damage during fractionated irradiation of human FaDu SCC

    International Nuclear Information System (INIS)

    Petersen, Cordula; Zips, Daniel; Krause, Mechthild; Voelkel, Wolfram; Thames, Howard D.; Baumann, Michael

    2005-01-01

    Background and purpose: The present study addresses whether recovery of sublethal damage in tumours may change during fractionated irradiation in FaDu human squamous cell carcinoma and whether such an effect might contribute to the pronounced time factor of fractionated irradiation previously found in this tumour. Patients and methods: FaDu tumours were transplanted s.c. into the right hind leg of NMRI nu/nu mice. Single doses or 2, 4, and 8 equal fractions in 3.5 days were applied in previously unirradiated tumours and after priming with 18 fractions of 3 Gy in 18 or 36 days. All irradiations were given under clamp hypoxic conditions. Experimental endpoints were tumour control dose 50% (TCD 50 ) and α/β values without and after priming. Results: Without priming TCD 50 increased with increasing number of fractions from 38.8 Gy (95% CI 35;45) after single dose irradiation to 54.0 Gy (42;57) after 8 fractions. No increase in TCD 50 when given in 1, 2, 4, or 8 fractions in 3.5 days was found after priming with 18 3-Gy fractions in 18 and 36 days. After priming with 18 fractions in 18 days TCD 50 remained constant at 25 Gy and after priming with 18 fractions in 36 days at 42 Gy. The α/β ratio without priming was 68 Gy (42;127). After fractionated irradiation with 18 3-Gy fractions in 18 and 36 days the α/β ratio increased to 317 Gy (38;∞) and to infinite, respectively. Conclusions: Our results indicate that clonogenic cells in FaDu tumours lose entirely their capacity to recover from sublethal radiation damage during fractionated irradiation. Therefore, an increased repair capacity as an explanation for the pronounced time factor of fractionated irradiation in this tumour can be ruled out

  5. Extra lethal damage due to residual incompletely repaired sublethal damage in hyperfractionated and continuous radiation treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.; van de Geijn, J.; Goffman, T. (ROB, DCT, NCI, NIH, Bethesda, Maryland 20892 (US))

    1991-05-01

    In the conventional linear--quadratic model of single-dose response, the {alpha} and {beta} terms reflect lethal damage created {ital during} the delivery of a dose, from two different presumed molecular processes, one linear with dose, the other quadratic. With the conventional one-fraction-per-day (or less) regimens, the sublethal damage (SLD), presumably repairing exponentially over time, is essentially completely fixed by the time of the next dose of radiation. If this assumption is true, the effects of subsequent fractions of radiation should be independent, that is, there should be little, if any, reversible damage left from previous fractions, at the time of the next dose. For multiple daily fractions, or for the limiting case, continuous radiation, this simplification may overlook damaged cells that have had insufficient time for repair. A generalized method is presented for accounting for extra lethal damage (ELD) arising from such residual SLD for hyperfractionation and continuous irradiation schemes. It may help to predict differences in toxicity and tumor control, if any, obtained with unconventional'' treatment regimens. A key element in the present model is the finite size and the dynamic character of the pool of sublethal damage. Besides creating the usual linear and quadratic components of lethal damage, each new fraction converts a certain fraction of the existing SLD into ELD, and creates some new SLD.

  6. Extra lethal damage due to residual incompletely repaired sublethal damage in hyperfractionated and continuous radiation treatment

    International Nuclear Information System (INIS)

    Chen, J.; van de Geijn, J.; Goffman, T.

    1991-01-01

    In the conventional linear--quadratic model of single-dose response, the α and β terms reflect lethal damage created during the delivery of a dose, from two different presumed molecular processes, one linear with dose, the other quadratic. With the conventional one-fraction-per-day (or less) regimens, the sublethal damage (SLD), presumably repairing exponentially over time, is essentially completely fixed by the time of the next dose of radiation. If this assumption is true, the effects of subsequent fractions of radiation should be independent, that is, there should be little, if any, reversible damage left from previous fractions, at the time of the next dose. For multiple daily fractions, or for the limiting case, continuous radiation, this simplification may overlook damaged cells that have had insufficient time for repair. A generalized method is presented for accounting for extra lethal damage (ELD) arising from such residual SLD for hyperfractionation and continuous irradiation schemes. It may help to predict differences in toxicity and tumor control, if any, obtained with ''unconventional'' treatment regimens. A key element in the present model is the finite size and the dynamic character of the pool of sublethal damage. Besides creating the usual linear and quadratic components of lethal damage, each new fraction converts a certain fraction of the existing SLD into ELD, and creates some new SLD

  7. Contact irritant responses of Aedes aegypti Using sublethal concentration and focal application of pyrethroid chemicals.

    Science.gov (United States)

    Manda, Hortance; Shah, Pankhil; Polsomboon, Suppaluck; Chareonviriyaphap, Theeraphap; Castro-Llanos, Fanny; Morrison, Amy; Burrus, Roxanne G; Grieco, John P; Achee, Nicole L

    2013-01-01

    Previous studies have demonstrated contact irritant and spatial repellent behaviors in Aedes aegypti following exposure to sublethal concentrations of chemicals. These sublethal actions are currently being evaluated in the development of a push-pull strategy for Ae. aegypti control. This study reports on mosquito escape responses after exposure to candidate chemicals for a contact irritant focused push-pull strategy using varying concentrations and focal application. Contact irritancy (escape) behavior, knockdown and 24 hour mortality rates were quantified in populations of female Ae. aegypti under laboratory conditions and validated in the field (Thailand and Peru) using experimental huts. Evaluations were conducted using varying concentrations and treatment surface area coverage (SAC) of three pyrethroid insecticides: alphacypermethrin, lambacyhalothrin and deltamethrin. Under laboratory conditions, exposure of Ae. aegypti to alphacypermethrin using the standard field application rate (FAR) resulted in escape responses at 25% and 50% SAC that were comparable with escape responses at 100% SAC. Significant escape responses were also observed at time of exit (by four hours) and 40% increase in escape using ½FAR of alphacypermethrin at 75% SAC compared to a matched chemical-free control. In Peru, however, the maximum increase in Ae. aegypti escape from alphacypermethrin-treated huts was 11%. Results presented here suggest a potential role for sublethal and focal application of contact irritant chemicals in an Ae. aegypti push-pull strategy to reduce human-vector contact inside treated homes. However, the impact of an increase in escape response on dengue virus transmission is currently unknown and will depend on rate of biting on human hosts prior to house exiting.

  8. Kinetics and capacity of repair of sublethal damage in mouse lip mucosa during fractionated irradiations

    International Nuclear Information System (INIS)

    Ang, K.K.; Xu, F.X.; Landuyt, W.; van der Schueren, E.

    1985-01-01

    The kinetics and capacity of repair of sublethal damage in mouse lip mucosa have been investigated. To assess the rate of repair 2 and 5 irradiations have been given with intervals ranging from 1 to 24 hours. It was found that the sublethal damage induced by a dose of approximately 10 Gy was fully recovered in approximately 4 hr. After a dose of 5-6 Gy, cellular repair was completed within 3 hr. The half time of repair (T1/2) was estimated to be approximately 72 min for 10 Gy and approximately 54 min for 5-6 Gy. Although these results suggest that the rate of repair is dependent on the fraction size, the possible influence of the amount of repair of sublethal radiation damage with the various fraction sizes used can not be ruled out. To evaluate the capacity of repair, a single dose, 2, 4 and 10 fractions have been given in a maximal overall time of 3 days in order to minimize the influence of repopulation. The slope of the isoeffective curve was 0.32 and the alpha/beta ratio was 8.5 Gy. This indicates that the capacity of cellular repair of lip mucosa is similar to those of other rapidly proliferating tissues but smaller than those of late responding tissues. The results of the present and other studies demonstrate that there are considerable differences in the repair characteristics between acutely and late responding tissues. These features have to be dealt with when fractionation schedules are markedly altered

  9. Radioprotection of mice by lactoferrin against irradiation with sublethal X-rays

    International Nuclear Information System (INIS)

    Nishimura, Yoshikazu; Homma-Takeda, Shino; Kim, Hee-Sun; Kakuta, Izuru

    2014-01-01

    The influence of a host defense protein, lactoferrin (LF), contained in exocrine secretions such as milk, on radiation disorder was investigated. A total of 25 C3H/He mice in each of two groups were maintained with 0.1% LF-added and LF-free diets, respectively, for one month. The mice were then treated with single whole-body X-ray irradiation at a sublethal dose (6.8 Gy), and the survival rate after irradiation was investigated. The survival rate at 30 d after irradiation was relatively higher in the LF group than in the control group (LF-free), (85 and 62%, respectively). The body weight 15 d after X-ray irradiation was also significantly greater in the LF group than in the control group. The hemoglobin level and hematocrit value were higher in the LF group at 5 d before X-ray irradiation. Another 52 mice underwent whole-body X-ray irradiation at the sublethal dose (6.8 Gy), and then LF was intraperitoneally injected once at 4 mg/animal to half of them. The survival rate in LF-treated mice 30 d after irradiation was 92%, significantly higher than in mice treated with saline (50%) (P = 0.0012). In addition, LF showed hydroxyl radical scavenger activity in vitro. These findings suggest that LF may inhibit radiation damage. (author)

  10. Interrill Erodibility of P and C on conventially and organically farmed Devon soils

    Science.gov (United States)

    Kuhn, N. J.

    2012-04-01

    Soil erosion can have significant off-site effects on water quality and thus human and habitat health. Apart from sedimentation, the transfer of nutrients, both dissolved and particulate, is a major concern. The particulate transfer of nutrients from agricultural land can occur either by rill or interrill erosion. Rill erosion is non-selective and affects only a limited extent of agricultural land. Interrill processes such as crusting, splash and raindrop-impacted wash, on the other hand, act on all cropland and affect the quality of the water from all areas generating runoff. A significant amount of phosphorus (P) is contained in the surface soil layer transformed by interrill processes annually. In the EU, the P content of a crusted (2 mm) surface layer corresponds to 4 to 40 kg ha-1 of P on arable land (1.094 mil km2). Therefore, the role of interrill processes and erosion for regional nutrient cycling requires close attention. Interrill erosion is a complex phenomenon, involving the detachment, transport and deposition of soil particles by raindrop impacted flow. Resistance to interrill erosion varies between soils depending on their physical, chemical and mineralogical properties. In addition, significant changes in soil resistance to interrill erosion occur during storms as a result of changes in surface roughness, cohesion and particle size. As a consequence, erosion on interrill areas is selective, moving the most easily detached small and/or light soil particles which are often enriched in clay, P and organic C. Commonly, the risk of erosion associated with organically farmed soils is lower than those farmed in a conventional way. This is attributed to greater aggregate stability and thus greater infiltration and lower erodibility. Erosion of nutrients on organically farmed soils is therefore considered to be reduced by the same order of magnitude than the amount of eroded soil compared to conventionally farmed soils. However, the selective nature of

  11. Toxicity and sublethal effects of seven insecticides to eggs of the flower bug Orius insidiosus (Say) (Hemiptera: Anthocoridae).

    Science.gov (United States)

    Moscardini, Valéria Fonseca; Gontijo, Pablo da Costa; Carvalho, Geraldo Andrade; Oliveira, Rodrigo Lopes de; Maia, Jader Braga; Silva, Fernanda Fonseca e

    2013-07-01

    The predatory bug Orius insidiosus is an important biological control agent of several insect pests, and is one of the most commonly used species in biological control programs worldwide. This study assessed the lethal and sublethal effects of insecticides on this species through life table, and classified the insecticides according to the definitions of toxicity given by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). A bioassay was carried out using a completely randomized design with eight treatments and 40 replicates. Eggs of O. insidiosus laid naturally in plant stems were immersed in aqueous solutions of the chemical products. Egg viability, duration of the embryonic period, survival of nymphs, and duration of the nymphal period were assessed daily. Insects that reached adulthood were paired and their reproduction assessed. The number of eggs produced and the survival of adults were assessed daily. The insecticides abamectin, cartap hydrochloride, spirotetramat+imidacloprid, and flubendiamid were classified as harmful. Pyriproxyfen and rynaxypyr were categorized as harmless and pymetrozine was classified as slightly harmful. Pyriproxyfen affected the population parameters rm, GT, DT, and λ, whereas other insecticides did not. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Chronic Exposure of Corals to Fine Sediments: Lethal and Sub-Lethal Impacts

    Science.gov (United States)

    Flores, Florita; Hoogenboom, Mia O.; Smith, Luke D.; Cooper, Timothy F.; Abrego, David; Negri, Andrew P.

    2012-01-01

    Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS) for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata) more than the upright branching species (Acropora millepora). The lowest sediment treatments that caused full colony mortality were 30 mg l−1 TSS (25 mg cm−2 day−1) for M. aequituberculata and 100 mg l−1 TSS (83 mg cm−2 day−1) for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue. PMID:22662225

  13. Chronic exposure of corals to fine sediments: lethal and sub-lethal impacts.

    Directory of Open Access Journals (Sweden)

    Florita Flores

    Full Text Available Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata more than the upright branching species (Acropora millepora. The lowest sediment treatments that caused full colony mortality were 30 mg l(-1 TSS (25 mg cm(-2 day(-1 for M. aequituberculata and 100 mg l(-1 TSS (83 mg cm(-2 day(-1 for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue.

  14. Development of a New Technique to Assess Susceptibility to Predation Resulting from Sublethal Stresses (Indirect Mortality)

    Energy Technology Data Exchange (ETDEWEB)

    Cada, G.F.

    2003-08-25

    from controls at 1-min post-exposure and for fathead minnows at 1- and 5-min post-exposure. The greatest effects occurred with exposure to the fish anesthetic; in fathead minnows all of the recorded measures were significantly different from controls at 1-min and 5-min post-exposure at the 100 mg/L dose. For striped shiners all recorded behavioral measures were significantly different from controls at 1-min at the 200 and 100 mg/L doses and for selected behavioral measures at 5-min. Turbulence also had significant effects on striped shiner startle responses following 20- and 30-min exposures for all behavioral measures at 1-min. The patterns suggest that any effects on startle response due to turbulence or low doses of anesthetic are short-lived, but can be evaluated using the escape behavior technique. The most useful indication of changes in escape behavior in these tests was the simple reaction/no reaction to the startle stimulus. The startle response occurred reliably among unstressed fish, and was frequently reduced or eliminated in fish exposed to turbulence or anesthesia. The other behavioral parameters observed were often altered by the sublethal stresses as well. A standard predator preference test was also conducted with largemouth bass as the predators and fathead minnows as prey. In this test design, groups of 10 unstressed fish (controls) and 10 stressed fish were put in a tank with a predator. The stressed fathead minnows were exposed to turbulence or fish anesthetic. The predator was allowed to eat half of the prey, and the data were evaluated to determine whether predators consumed greater proportions of stressed minnows than control minnows. The predation test indicated that exposure to MS-222 resulted in significant predation in fathead minnows, but exposure to turbulence did not. This pattern was the same as seen in fathead minnows using the startle response (escape behavior) test. For the sublethal stresses we applied, evaluation of changes in fish

  15. Toxicity of sediments from Bahía de Chetumal, México, as assessed by hepatic EROD induction and histology in nile tilapia Oreochromis niloticus.

    Science.gov (United States)

    Zapata-Pérez, O; Simá-Alvarez, R; Noreña-Barroso, E; Güemes, J; Gold-Bouchot, G; Ortega, A; Albores-Medina, A

    2000-01-01

    The effect of environmental pollutants present in sediments obtained from Bahía de Chetumal, a bay on the border between Mexico and Belize, was studied in nile tilapia (Oreochromis niloticus) intraperitoneally injected with sediment extracts from six different sites of the Bay. Sediment samples used for the study contained a variety of organic chemicals such as organochlorine pesticides, polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs). Total cytochrome P-450 and EROD activity were measured in fish liver. Haematological and histological analyses were also carried out. Hepatic P-450 content in treated fish increased from 43 to 240%, and EROD activity from 85 to 160% compared to controls. Extracts from two sampling sites inhibited EROD activity. There were positive significant correlations between P-450 content and the levels of PCBs 44 and 128. EROD activity correlated to HCB, op'-DDE, pp'-DDE, pp'-DDD, mirex and PCB 18 concentrations. Blood examination showed cell degeneration and binucleated leukocytes with abnormal chromatin. Extract treatment also resulted in foci of hyperplasia on the basement of gill lamellae, hypertrophy and oedema in gills and liver necrosis. Control fish showed no abnormalities. The results demonstrate that sediments from Bahía of Chetumal have the potential to cause histopathological, haematological and biochemical alterations in fish. The administration of sediment extracts to fish may serve as a useful test to screen the toxicity of sediments from different areas.

  16. Fluvial organic carbon flux from an eroding peatland catchment, southern Pennines, UK

    Directory of Open Access Journals (Sweden)

    R. R. Pawson

    2008-03-01

    Full Text Available This study investigates for the first time the relative importance of dissolved organic carbon (DOC and particulate organic carbon (POC in the fluvial carbon flux from an actively eroding peatland catchment in the southern Pennines, UK. Event scale variability in DOC and POC was examined and the annual flux of fluvial organic carbon was estimated for the catchment. At the event scale, both DOC and POC were found to increase with discharge, with event based POC export accounting for 95% of flux in only 8% of the time. On an annual cycle, exports of 35.14 t organic carbon (OC are estimated from the catchment, which represents an areal value of 92.47 g C m−2 a−1. POC was the most significant form of organic carbon export, accounting for 80% of the estimated flux. This suggests that more research is required on both the fate of POC and the rates of POC export in eroding peatland catchments.

  17. Some heterocyclic aromatic compounds are Ah receptor agonists in the DR-CALUX assay and the EROD assay with RTL-W1 cells.

    Science.gov (United States)

    Hinger, Gunnar; Brinkmann, Markus; Bluhm, Kerstin; Sagner, Anne; Takner, Helena; Eisenträger, Adolf; Braunbeck, Thomas; Engwall, Magnus; Tiehm, Andreas; Hollert, Henner

    2011-09-01

    Heterocyclic aromatic compounds containing nitrogen, sulfur, or oxygen heteroatoms (NSO-HET) have been detected in air, soil, marine, and freshwater systems. However, only few publications are available investigating NSO-HET using in vitro bioassays. To support better characterization of environmental samples, selected NSO-HET were screened for dioxin-like activity in two bioassays. The present study focuses on the identification and quantification of dioxin-like effects of 12 NSO-HET using the DR-CALUX assay, and the 7-ethoxyresorufin-O-deethylase (EROD) assay with the permanent fish liver cell line RTL-W1. Changes of the total medium compound concentrations during the test procedure due to, e.g., sorption or volatilization were quantified using GC/MS. The NSO-HET benzofuran, 2,3-dimethylbenzofuran, dibenzofuran, dibenzothiophen, acridine, xanthene, and carbazole caused a response in the DR-CALUX assay. Only benzofuran and 2,3-dimethylbenzofuran were also positive in the EROD assay. All other compounds were inactive in the EROD assay. Relative potency (REP) values ranged from (2.80 ± 1.32) · 10(-8) to (3.26 ± 2.03) · 10(-6) in the DR-CALUX and from (3.26 ± 0.91) · 10(-7) to (4.87 ± 1.97) · 10(-7) in the EROD assay. The REP values were comparable to those of larger polycyclic aromatic hydrocarbons, e.g., fluoranthene and pyrene. Thus, and because of the ubiquitous distribution of heterocyclic aromatic compounds in the environment, the provided data will further facilitate the bioanalytical and analytical characterization of environmental samples towards these toxicants.

  18. Effects of Sublethal Fungicides on Mutation Rates and Genomic Variation in Fungal Plant Pathogen, Sclerotinia sclerotiorum.

    Science.gov (United States)

    Amaradasa, B Sajeewa; Everhart, Sydney E

    2016-01-01

    Pathogen exposure to sublethal doses of fungicides may result in mutations that may represent an important and largely overlooked mechanism of introducing new genetic variation into strictly clonal populations, including acquisition of fungicide resistance. We tested this hypothesis using the clonal plant pathogen, Sclerotinia sclerotiorum. Nine susceptible isolates were exposed independently to five commercial fungicides with different modes of action: boscalid (respiration inhibitor), iprodione (unclear mode of action), thiophanate methyl (inhibition of microtubulin synthesis) and azoxystrobin and pyraclostrobin (quinone outside inhibitors). Mycelium of each isolate was inoculated onto a fungicide gradient and sub-cultured from the 50-100% inhibition zone for 12 generations and experiment repeated. Mutational changes were assessed for all isolates at six neutral microsatellite (SSR) loci and for a subset of isolates using amplified fragment length polymorphisms (AFLPs). SSR analysis showed 12 of 85 fungicide-exposed isolates had a total of 127 stepwise mutations with 42 insertions and 85 deletions. Most stepwise deletions were in iprodione- and azoxystrobin-exposed isolates (n = 40/85 each). Estimated mutation rates were 1.7 to 60-fold higher for mutated loci compared to that expected under neutral conditions. AFLP genotyping of 33 isolates (16 non-exposed control and 17 fungicide exposed) generated 602 polymorphic alleles. Cluster analysis with principal coordinate analysis (PCoA) and discriminant analysis of principal components (DAPC) identified fungicide-exposed isolates as a distinct group from non-exposed control isolates (PhiPT = 0.15, P = 0.001). Dendrograms based on neighbor-joining also supported allelic variation associated with fungicide-exposure. Fungicide sensitivity of isolates measured throughout both experiments did not show consistent trends. For example, eight isolates exposed to boscalid had higher EC50 values at the end of the experiment, and

  19. Effects of Sublethal Fungicides on Mutation Rates and Genomic Variation in Fungal Plant Pathogen, Sclerotinia sclerotiorum.

    Directory of Open Access Journals (Sweden)

    B Sajeewa Amaradasa

    Full Text Available Pathogen exposure to sublethal doses of fungicides may result in mutations that may represent an important and largely overlooked mechanism of introducing new genetic variation into strictly clonal populations, including acquisition of fungicide resistance. We tested this hypothesis using the clonal plant pathogen, Sclerotinia sclerotiorum. Nine susceptible isolates were exposed independently to five commercial fungicides with different modes of action: boscalid (respiration inhibitor, iprodione (unclear mode of action, thiophanate methyl (inhibition of microtubulin synthesis and azoxystrobin and pyraclostrobin (quinone outside inhibitors. Mycelium of each isolate was inoculated onto a fungicide gradient and sub-cultured from the 50-100% inhibition zone for 12 generations and experiment repeated. Mutational changes were assessed for all isolates at six neutral microsatellite (SSR loci and for a subset of isolates using amplified fragment length polymorphisms (AFLPs. SSR analysis showed 12 of 85 fungicide-exposed isolates had a total of 127 stepwise mutations with 42 insertions and 85 deletions. Most stepwise deletions were in iprodione- and azoxystrobin-exposed isolates (n = 40/85 each. Estimated mutation rates were 1.7 to 60-fold higher for mutated loci compared to that expected under neutral conditions. AFLP genotyping of 33 isolates (16 non-exposed control and 17 fungicide exposed generated 602 polymorphic alleles. Cluster analysis with principal coordinate analysis (PCoA and discriminant analysis of principal components (DAPC identified fungicide-exposed isolates as a distinct group from non-exposed control isolates (PhiPT = 0.15, P = 0.001. Dendrograms based on neighbor-joining also supported allelic variation associated with fungicide-exposure. Fungicide sensitivity of isolates measured throughout both experiments did not show consistent trends. For example, eight isolates exposed to boscalid had higher EC50 values at the end of the

  20. Effects of Sublethal Fungicides on Mutation Rates and Genomic Variation in Fungal Plant Pathogen, Sclerotinia sclerotiorum

    Science.gov (United States)

    Amaradasa, B. Sajeewa

    2016-01-01

    Pathogen exposure to sublethal doses of fungicides may result in mutations that may represent an important and largely overlooked mechanism of introducing new genetic variation into strictly clonal populations, including acquisition of fungicide resistance. We tested this hypothesis using the clonal plant pathogen, Sclerotinia sclerotiorum. Nine susceptible isolates were exposed independently to five commercial fungicides with different modes of action: boscalid (respiration inhibitor), iprodione (unclear mode of action), thiophanate methyl (inhibition of microtubulin synthesis) and azoxystrobin and pyraclostrobin (quinone outside inhibitors). Mycelium of each isolate was inoculated onto a fungicide gradient and sub-cultured from the 50–100% inhibition zone for 12 generations and experiment repeated. Mutational changes were assessed for all isolates at six neutral microsatellite (SSR) loci and for a subset of isolates using amplified fragment length polymorphisms (AFLPs). SSR analysis showed 12 of 85 fungicide-exposed isolates had a total of 127 stepwise mutations with 42 insertions and 85 deletions. Most stepwise deletions were in iprodione- and azoxystrobin-exposed isolates (n = 40/85 each). Estimated mutation rates were 1.7 to 60-fold higher for mutated loci compared to that expected under neutral conditions. AFLP genotyping of 33 isolates (16 non-exposed control and 17 fungicide exposed) generated 602 polymorphic alleles. Cluster analysis with principal coordinate analysis (PCoA) and discriminant analysis of principal components (DAPC) identified fungicide-exposed isolates as a distinct group from non-exposed control isolates (PhiPT = 0.15, P = 0.001). Dendrograms based on neighbor-joining also supported allelic variation associated with fungicide-exposure. Fungicide sensitivity of isolates measured throughout both experiments did not show consistent trends. For example, eight isolates exposed to boscalid had higher EC50 values at the end of the experiment

  1. Comparative study on the immunocompetent activity of three different kinds of Peh-Hue-Juwa-Chi-Cao, Hedyotis diffusa, H. corymbosa and Mollugo pentaphylla after sublethal whole body X-irradiation

    International Nuclear Information System (INIS)

    Yang JenqJer; Hsu HsueYin; Ho YauHui; Lin ChunChing

    1997-01-01

    This brief communication describes the immunocompetent activity of the Chinese folk-medicinal herbs, Hedyotis corymbosa, H. diffusa and Mollugo pentaphylla in mice after moderate whole body x-irradiation. These antitumour drugs, given at doses of 500 and 1000 mg/kg/day for 7 consecutive days before x-irradiation protected ICR strain mice from the sublethal effects of radiation at a dose of 4 Gy, especially for the dose at 1000 mg/kg. Prior administration of H. corymbosa and H. diffusa ameliorated the leukopenia and splenic cellular decrease induced by sublethal irradiation, and slightly increased the immunocompetence of splenic cells after being stimulated by mitogens. However, administration of M. pentaphylla before x-irradiation exerted a less protective effect on ameliorating leukopenia and on splenic cellular immunocompetence. These findings suggest that some types of Peh-Hue-Juwa-Chi-Caoi (PHJCC) may also be effective in the prevention of haematopoietic damage when used in combination with radiotherapy. (author)

  2. Comparative study on the immunocompetent activity of three different kinds of Peh-Hue-Juwa-Chi-Cao, Hedyotis diffusa, H. corymbosa and Mollugo pentaphylla after sublethal whole body X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    JenqJer, Yang; HsueYin, Hsu; YauHui, Ho; ChunChing, Lin [School of Pharmacy, Kaohsiung Medical College, Kaohsiung, Taiwan (China)

    1997-07-01

    This brief communication describes the immunocompetent activity of the Chinese folk-medicinal herbs, Hedyotis corymbosa, H. diffusa and Mollugo pentaphylla in mice after moderate whole body x-irradiation. These antitumour drugs, given at doses of 500 and 1000 mg/kg/day for 7 consecutive days before x-irradiation protected ICR strain mice from the sublethal effects of radiation at a dose of 4 Gy, especially for the dose at 1000 mg/kg. Prior administration of H. corymbosa and H. diffusa ameliorated the leukopenia and splenic cellular decrease induced by sublethal irradiation, and slightly increased the immunocompetence of splenic cells after being stimulated by mitogens. However, administration of M. pentaphylla before x-irradiation exerted a less protective effect on ameliorating leukopenia and on splenic cellular immunocompetence. These findings suggest that some types of Peh-Hue-Juwa-Chi-Caoi (PHJCC) may also be effective in the prevention of haematopoietic damage when used in combination with radiotherapy. (author)

  3. Harlequin duck capture and EROD activity data from Prince William Sound, Alaska, 2011, 2013, 2014

    Data.gov (United States)

    Department of the Interior — This data set includes capture information and ethoxyresorufin­O­deethylase (EROD) activity results for harlequin ducks sampled during March 2011, 2013, and 2014 in...

  4. Granular flows on erodible layers: type and evolution of flow and deposit structures

    Science.gov (United States)

    Crosta, G.; De Blasio, F.; De Caro, M.; Volpi, G.; Frattini, P.

    2012-04-01

    The interaction of a fast moving landslide mass with the basal layer over which movement takes place has been discussed in previous contributions. Nevertheless, the evolution of the structures within the moving mass and the erodible layer are still to be described in detail (Hungr and Evans, 2004; Crosta et al., 1992, 2006, 2009, 2011; Dufresne et al., 2010; Mangeney et al., 2010) and modeling results (Crosta et al., 2006, 2009, 2011; Mangeney et al., 2010). We present some of the results from a campaign of laboratory experiments aimed at studying the evolution of a granular flow at the impact with and during the successive spreading over a cohesionless erodible layer. We performed these test to study the processes and to collect data and evidences to compare them with the results of numerical simulations and to verify capabilities of numerical codes. The laboratory setup consists of an inclined slope and an horizontal sector where release and transport, and deposition take place, respectively. Materials used for the tests are: a uniform rounded siliceous sand (Hostun sand; 0.125-0.5 mm) commonly adopted in lab tests because free of scale effects, and a gravel made of angular elements (12 mm in ave. size). Both the materials have been tested in dry conditions. Different slope angles have been tested (40, 45, 50, 55, 50, 66°) as well as different thicknesses of the erodible layer (0, 0.5, 1, 2 cm) and volumes of the released material (1.5, 3, 5, 9.6 liters). Tests have been monitored by means of a high speed camera and the pre- and post-failure geometries have been surveyed by means of a laser scanner. Deposit description allowed also the computation of volumes and the characterization of the different structures developed and frozen into the deposit. Experiments allowed us to observe the extreme processes occurring during the movement and the mise en place of the deposits. In particular, we observe the formation of a clear wave-like feature developing during the

  5. Concentration of electrolyte reserves of the juvenile african catfish clarias gariepinus (burchell, 1822) exposed to sublethal concentrations of portland cement powder in solution

    International Nuclear Information System (INIS)

    Adamu, M.K.; Francis, O.A.

    2008-01-01

    The study investigated the effect of sublethal concentrations (39.10, 19.55, 9.87 and 0.00 mg/l) of Portland cement powder in solution on the electrolyte reserves (sodium, potassium, calcium, chloride and inorganic phosphorus) in the serum, liver and kidney of the juvenile African catfish Clarias gariepinus after a 15 day exposure period. The basic function of the determined electrolyte reserves in the body lies in controlling fluid distribution, intra and extra cellular acidobasic equilibrium, maintaining osmotic pressure of body fluid and normal neuro-muscular irritability. The result revealed significant (P 0.05) changes in inorganic phosphorus. Sodium, calcium, chloride and inorganic phosphorus and potassium were significantly (P 0.05) different in liver and kidney, respectively. Ipso-facto, the effector organs viz: liver and kidney of teleost species - Clarias gariepinus which are primarily responsible for regulating water and ionic movement between external and internal milieu of fishes are susceptible to deleterious effects of Portland cement powder thus sublethal concentration (39.10 mg/l) of Portland cement powder in solution after a 15 day exposure has been most toxic and debilitating to the test fish. (author)

  6. Effects of sublethal exposure to lead on levels of energetic compounds in Procambarus clarkii (Girard, 1852)

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, M.; Torreblanca, A.; Del Ramo, J.; Diaz-Mayans, J. (Univ. of Valencia (Spain))

    1994-05-01

    Lead is neither essential nor beneficial to living organisms; all existing data show that its metabolic effects are adverse. Lead is toxic to all phyla of aquatic biota. Most of the lead discharged into surface water is rapidly incorporated into suspended and bottom sediments. The American red crayfish, Procambarus clarkii, lives in a wide range of environmental conditions that include highly polluted waters. Lead present in take sediments can be available to aquatic animals such as P. clarkii because it is a detritivor and burrow into the sediment. In fact, we found remarkable levels of lead in tissues of P. clarkii caught in Albufera Lake and kept 15 days in clean water (e. g. 223 [mu]g/g dry weight in gills). Furthermore, P. clarkii has a high capacity for lead accumulation from water, and gills were the most important tissue of lead accumulation. Among effects that contaminants have on the physiology of the organisms, energetic state variables are important, since they will alter both survival and reproduction. Hepatopancreas is a major site for the energetic reserve in crayfish and is a site of lead accumulation, although metal concentration in this organ is not as high as gills. The purpose of this study was to examine changes in energy reserves in hepatopancreas and gills of the crayfish P. clarkii, in response to sublethal exposure to lead. Gills are directly exposed to contaminants in the environment, and they are the first organ showing alterations by the action of the contaminants. Hepatopancreas was also chosen due to both, its relevance in the energetic metabolism and its role in heavy metal detoxification mechanisms.

  7. Chronic exposure to sublethal doses of radiation mimetic ZeocinTM selects for clones deficient in homologous recombination

    International Nuclear Information System (INIS)

    Delacote, Fabien; Deriano, Ludovic; Lambert, Sarah; Bertrand, Pascale; Saintigny, Yannick; Lopez, Bernard S.

    2007-01-01

    DNA double-strand breaks (DSBs) are highly toxic lesions leading to genome variability/instability. The balance between homologous recombination (HR) and non-homologous end-joining (NHEJ), two alternative DSB repair systems, is essential to ensure genome maintenance in mammalian cells. Here, we transfected CHO hamster cells with the pcDNA TM 3.1/Zeo plasmid, and selected transfectants with Zeocin TM , a bleomycin analog which produces DSBs. Despite the presence of a Zeocin TM resistance gene in pcDNA TM 3.1/Zeo, Zeocin TM induced 8-10 γ-H2AX foci per cell. This shows that the Zeocin TM resistance gene failed to fully detoxify cells treated with Zeocin TM , and that during selection cells were submitted to a chronic sublethal DSB stress. Selected clones show decreases in both spontaneous and induced intrachromosomal HR. In contrast, in an in vitro assay, these clones show an increase in NHEJ products specific to the KU86 pathway. We selected cells, in the absence of pcDNA TM 3.1/Zeo, with low and sublethal doses of Zeocin TM , producing a mean 8-10 γ-H2AX foci per cell. Newly selected clones exhibited similar phenotypes: HR decrease accompanied by an increase in KU86-dependent NHEJ efficiency. Thus chronic exposure to sublethal numbers of DSBs selects cells whose HR versus NHEJ balance is altered. This may well have implications for radio- and chemotherapy, and for management of environmental hazards

  8. Sub-lethal irradiation of human colorectal tumor cells imparts enhanced and sustained susceptibility to multiple death receptor signaling pathways.

    Directory of Open Access Journals (Sweden)

    Victoria Ifeadi

    Full Text Available BACKGROUND: Death receptors (DR of the TNF family function as anti-tumor immune effector molecules. Tumor cells, however, often exhibit DR-signaling resistance. Previous studies indicate that radiation can modify gene expression within tumor cells and increase tumor cell sensitivity to immune attack. The aim of this study is to investigate the synergistic effect of sub-lethal doses of ionizing radiation in sensitizing colorectal carcinoma cells to death receptor-mediated apoptosis. METHODOLOGY/PRINCIPAL FINDINGS: The ability of radiation to modulate the expression of multiple death receptors (Fas/CD95, TRAILR1/DR4, TRAILR2/DR5, TNF-R1 and LTβR was examined in colorectal tumor cells. The functional significance of sub-lethal doses of radiation in enhancing tumor cell susceptibility to DR-induced apoptosis was determined by in vitro functional sensitivity assays. The longevity of these changes and the underlying molecular mechanism of irradiation in sensitizing diverse colorectal carcinoma cells to death receptor-mediated apoptosis were also examined. We found that radiation increased surface expression of Fas, DR4 and DR5 but not LTβR or TNF-R1 in these cells. Increased expression of DRs was observed 2 days post-irradiation and remained elevated 7-days post irradiation. Sub-lethal tumor cell irradiation alone exhibited minimal cell death, but effectively sensitized three of three colorectal carcinoma cells to both TRAIL and Fas-induced apoptosis, but not LTβR-induced death. Furthermore, radiation-enhanced Fas and TRAIL-induced cell death lasted as long as 5-days post-irradiation. Specific analysis of intracellular sensitizers to apoptosis indicated that while radiation did reduce Bcl-X(L and c-FLIP protein expression, this reduction did not correlate with the radiation-enhanced sensitivity to Fas and/or TRAIL mediated apoptosis among the three cell types. CONCLUSIONS/SIGNIFICANCE: Irradiation of tumor cells can overcome Fas and TRAIL

  9. Hematologic status of mice submitted to sublethal total body irradiation with mixed neutron-gamma radiation

    International Nuclear Information System (INIS)

    Herodin, F.; Court, L.

    1989-01-01

    The hematologic status of mice exposed to sublethal whole body irradiation with mixed neutron-gamma radiation (mainly neutrons) is studied. A slight decrease of the blood cell count is still observed below 1 Gy. The recovery of bone marrow granulocyte-macrophage progenitors seems to require more time than after pure gamma irradiation [fr

  10. Sublethal effects of herbicides on the biomass and seed production of terrestrial non-crop plant species, influenced by environment, development stage and assessment date

    International Nuclear Information System (INIS)

    Riemens, Marleen M.; Dueck, Thom; Kempenaar, Corne; Lotz, Lambertus A.P.; Kropff, Martin J.J.

    2009-01-01

    Guidelines provided by the OECD and EPPO allow the use of single-species tests performed in greenhouses to assess the risk of herbicides to non-target terrestrial plant communities in the field. The present study was undertaken to investigate the use of greenhouse data to determine effects of herbicides with a different mode of action on the biomass, seed production and emergence of field-grown plants. In addition, a single species approach was compared with a mixed species approach. Effects on the biomass of greenhouse and field-grown plants were found to be related at different effect levels, indicating that it might be possible to translate results from greenhouse studies to field situations. However, the use of single-species tests may not be valid. The response of a single plant species to sublethal herbicide dosages differed to the response of the same species grown in a mixture with other species. - The use of single-species greenhouse tests in the ecological risk assessment of crop protection products may only be valid for single species in the field, not for vegetations.

  11. Subchronic exposure to sublethal dose of imidacloprid changes electrophysiological properties and expression pattern of nicotinic acetylcholine receptor subtypes in insect neurosecretory cells.

    Science.gov (United States)

    Benzidane, Yassine; Goven, Delphine; Abd-Ella, Aly Ahmed; Deshayes, Caroline; Lapied, Bruno; Raymond, Valérie

    2017-09-01

    Neonicotinoids are the most important class of insecticides used in agriculture over the last decade. They act as selective agonists of insect nicotinic acetylcholine receptors (nAChRs). The emergence of insect resistance to these insecticides is one of the major problems, which limit the use of neonicotinoids. The aim of our study is to better understand physiological changes appearing after subchronic exposure to sublethal doses of insecticide using complementary approaches that include toxicology, electrophysiology, molecular biology and calcium imaging. We used cockroach neurosecretory cells identified as dorsal unpaired median (DUM) neurons, known to express two α-bungarotoxin-insensitive (α-bgt-insensitive) nAChR subtypes, nAChR1 and nAChR2, which differ in their sensitivity to imidacloprid. Although nAChR1 is sensitive to imidacloprid, nAChR2 is insensitive to this insecticide. In this study, we demonstrate that subchronic exposure to sublethal dose of imidacloprid differentially changes physiological and molecular properties of nAChR1 and nAChR2. Our findings reported that this treatment decreased the sensitivity of nAChR1 to imidacloprid, reduced current density flowing through this nAChR subtype but did not affect its subunit composition (α3, α8 and β1). Subchronic exposure to sublethal dose of imidacloprid also affected nAChR2 functions. However, these effects were different from those reported on nAChR1. We observed changes in nAChR2 conformational state, which could be related to modification of the subunit composition (α1, α2 and β1). Finally, the subchronic exposure affecting both nAChR1 and nAChR2 seemed to be linked to the elevation of the steady-state resting intracellular calcium level. In conclusion, under subchronic exposure to sublethal dose of imidacloprid, cockroaches are capable of triggering adaptive mechanisms by reducing the participation of imidacloprid-sensitive nAChR1 and by optimizing functional properties of nAChR2, which is

  12. Sublethal effects of catch-and-release fishing: measuring capture stress, fish impairment, and predation risk using a condition index

    Science.gov (United States)

    Campbell, Matthew D.; Patino, Reynaldo; Tolan, J.M.; Strauss, R.E.; Diamond, S.

    2009-01-01

    The sublethal effects of simulated capture of red snapper (Lutjanus campechanus) were analysed using physiological responses, condition indexing, and performance variables. Simulated catch-and-release fishing included combinations of depth of capture and thermocline exposure reflective of environmental conditions experienced in the Gulf of Mexico. Frequency of occurrence of barotrauma and lack of reflex response exhibited considerable individual variation. When combined into a single condition or impairment index, individual variation was reduced, and impairment showed significant increases as depth increased and with the addition of thermocline exposure. Performance variables, such as burst swimming speed (BSS) and simulated predator approach distance (AD), were also significantly different by depth. BSSs and predator ADs decreased with increasing depth, were lowest immediately after release, and were affected for up to 15 min, with longer recovery times required as depth increased. The impairment score developed was positively correlated with cortisol concentration and negatively correlated with both BSS and simulated predator AD. The impairment index proved to be an efficient method to estimate the overall impairment of red snapper in the laboratory simulations of capture and shows promise for use in field conditions, to estimate release mortality and vulnerability to predation.

  13. Sublethal Effects of the Neonicotinoid Insecticide Thiamethoxam on the Transcriptome of the Honey Bees (Hymenoptera: Apidae).

    Science.gov (United States)

    Shi, Teng-Fei; Wang, Yu-Fei; Liu, Fang; Qi, Lei; Yu, Lin-Sheng

    2017-12-05

    Neonicotinoid insecticides are now the most widely used insecticides in the world. Previous studies have indicated that sublethal doses of neonicotinoids impair learning, memory capacity, foraging, and immunocompetence in honey bees (Apis mellifera, Linnaeus) (Hymenoptera: Apidae). Despite these, few studies have been carried out on the molecular effects of neonicotinoids. In this study, we focus on the second-generation neonicotinoid thiamethoxam, which is currently widely used in agriculture to protect crops. Using high-throughput RNA-Seq, we investigated the transcriptome profile of honey bees after subchronic exposure to 10 ppb thiamethoxam over 10 d. In total, 609 differentially expressed genes (DEGs) were identified, of which 225 were upregulated and 384 were downregulated. Several genes, including vitellogenin, CSP3, defensin-1, Mrjp1, and Cyp6as5 were selected and further validated using real-time quantitative polymerase chain reaction assays. The functions of some DEGs were identified, and Gene Ontology-enrichment analysis showed that the enriched DEGs were mainly linked to metabolism, biosynthesis, and translation. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that thiamethoxam affected biological processes including ribosomes, the oxidative phosphorylation pathway, tyrosine metabolism pathway, pentose and glucuronate interconversions, and drug metabolism. Overall, our results provide a basis for understanding the molecular mechanisms of the complex interactions between neonicotinoid insecticides and honey bees. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. How Welfare Regimes Generate and Erode Social Capital

    DEFF Research Database (Denmark)

    Larsen, Christian Albrekt

    2007-01-01

    in the USA and other liberal welfare regimes, while social capital is stable in the so-called social democratic and conservative welfare regimes. The second puzzle is why the group of social democratic regimes have extremely high levels of social trust. It is argued that both puzzles have to do......Comparative studies of social capital, operationalised as social trust between citizens, have revealed two major puzzles. The first puzzle has to do with the decline in social trust in the USA, which fuelled considerable debate about social capital. The question is why social capital erodes...... with the presence or absence of a poor and culturally distinct underclass. The social democratic welfare regimes hinder – while the liberal welfare regime generate – such underclass phenomena....

  15. Eroding market stability by proliferation of financial instruments

    Science.gov (United States)

    Caccioli, F.; Marsili, M.; Vivo, P.

    2009-10-01

    We contrast Arbitrage Pricing Theory (APT), the theoretical basis for the development of financial instruments, with a dynamical picture of an interacting market, in a simple setting. The proliferation of financial instruments apparently provides more means for risk diversification, making the market more efficient and complete. In the simple market of interacting traders discussed here, the proliferation of financial instruments erodes systemic stability and it drives the market to a critical state characterized by large susceptibility, strong fluctuations and enhanced correlations among risks. This suggests that the hypothesis of APT may not be compatible with a stable market dynamics. In this perspective, market stability acquires the properties of a common good, which suggests that appropriate measures should be introduced in derivative markets, to preserve stability. in here

  16. Enhancement of committed hematopoietic stem cell colony formation by nandrolone decanoate after sublethal whole body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gallicchio, V.S.; Chen, M.G.; Watts, T.D.

    1984-11-01

    The ability of an anabolic steroid, nandrolone decanoate, to increase committed topoietic stem cell (CFU-gm, CFU-e, and BFU-e) colony formation after sublethal irradiation was evaluated. Immediately after receiving whole body irradiation and on the next two days, each mouse was injected intraperitoneally with nandrolone decanoate (1.25 mg) in propylene glycol. Irradiated control mice received only propylene glycol. Compared to controls, drug-treated mice showed marked peripheral blood leukocytosis and more stable packed red cell volume. Drug-treated mice also demonstrated increased erythropoiesis, as CFU-e/BFU-e concentrations from both marrow (9% to 581%) and spleen (15% to 797%) were elevated. Granulopoiesis was increased similarly, as CFU-gm concentrations from marrow (38% to 685%) and spleen (9% to 373%) were elevated. These results demonstrate that nandrolone decanoate enhances hematopoietic stem cell recovery after sublethal whole body irradiation. This suggests that following hematopoietic suppression, nandrolone decanoate may stimulate the recovery of hematopoiesis at the stem cell level and in peripheral blood.

  17. Enhancement of committed hematopoietic stem cell colony formation by nandrolone decanoate after sublethal whole body irradiation

    International Nuclear Information System (INIS)

    Gallicchio, V.S.; Chen, M.G.; Watts, T.D.

    1984-01-01

    The ability of an anabolic steroid, nandrolone decanoate, to increase committed topoietic stem cell (CFU-gm, CFU-e, and BFU-e) colony formation after sublethal irradiation was evaluated. Immediately after receiving whole body irradiation and on the next two days, each mouse was injected intraperitoneally with nandrolone decanoate (1.25 mg) in propylene glycol. Irradiated control mice received only propylene glycol. Compared to controls, drug-treated mice showed marked peripheral blood leukocytosis and more stable packed red cell volume. Drug-treated mice also demonstrated increased erythropoiesis, as CFU-e/BFU-e concentrations from both marrow (9% to 581%) and spleen (15% to 797%) were elevated. Granulopoiesis was increased similarly, as CFU-gm concentrations from marrow (38% to 685%) and spleen (9% to 373%) were elevated. These results demonstrate that nandrolone decanoate enhances hematopoietic stem cell recovery after sublethal whole body irradiation. This suggests that following hematopoietic suppression, nandrolone decanoate may stimulate the recovery of hematopoiesis at the stem cell level and in peripheral blood

  18. Tolerance development in Listeria monocytogenes-Escherichia coli dual-species biofilms after sublethal exposures to pronase-benzalkonium chloride combined treatments.

    Science.gov (United States)

    Rodríguez-López, Pedro; Cabo, Marta López

    2017-10-01

    This study was designed to assess the effects that sublethal exposures to pronase (PRN) and benzalkonium chloride (BAC) combined treatments have on Listeria monocytogenes-Escherichia coli dual-species biofilms grown on stainless steel in terms of tolerance development (TD) to these compounds. Additionally, fluorescence microscopy was used to observe the changes of the biofilm structure. PRN-BAC exposure was carried out using three different approaches and TD was evaluated treating biofilms with a final 100 μg/ml PRN followed by 50 μg/ml BAC combined treatment. Results showed that exposure to PRN-BAC significantly decreased the number of adhered L. monocytogenes (P reduction values were generally lower in L. monocytogenes compared to E. coli. Additionally, microscopy images showed an altered morphology produced by sublethal PRN-BAC in exposed L. monocytogenes-E. coli dual-species biofilms compared to control samples. Results also demonstrated that L. monocytogenes-E. coli dual-species biofilms are able to develop tolerance to PRN-BAC combined treatments depending on way they have been previously exposed. Moreover, they suggest that the generation of bacterial tolerance should be included as a parameter for sanitation procedures design. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Contact irritant responses of Aedes aegypti Using sublethal concentration and focal application of pyrethroid chemicals.

    Directory of Open Access Journals (Sweden)

    Hortance Manda

    Full Text Available BACKGROUND: Previous studies have demonstrated contact irritant and spatial repellent behaviors in Aedes aegypti following exposure to sublethal concentrations of chemicals. These sublethal actions are currently being evaluated in the development of a push-pull strategy for Ae. aegypti control. This study reports on mosquito escape responses after exposure to candidate chemicals for a contact irritant focused push-pull strategy using varying concentrations and focal application. METHODS: Contact irritancy (escape behavior, knockdown and 24 hour mortality rates were quantified in populations of female Ae. aegypti under laboratory conditions and validated in the field (Thailand and Peru using experimental huts. Evaluations were conducted using varying concentrations and treatment surface area coverage (SAC of three pyrethroid insecticides: alphacypermethrin, lambacyhalothrin and deltamethrin. RESULTS: Under laboratory conditions, exposure of Ae. aegypti to alphacypermethrin using the standard field application rate (FAR resulted in escape responses at 25% and 50% SAC that were comparable with escape responses at 100% SAC. Significant escape responses were also observed at <100% SAC using ½FAR of all test compounds. In most trials, KD and 24 hour mortality rates were higher in mosquitoes that did not escape than in those that escaped. In Thailand, field validation studies indicated an early time of exit (by four hours and 40% increase in escape using ½FAR of alphacypermethrin at 75% SAC compared to a matched chemical-free control. In Peru, however, the maximum increase in Ae. aegypti escape from alphacypermethrin-treated huts was 11%. CONCLUSIONS/SIGNIFICANCE: Results presented here suggest a potential role for sublethal and focal application of contact irritant chemicals in an Ae. aegypti push-pull strategy to reduce human-vector contact inside treated homes. However, the impact of an increase in escape response on dengue virus transmission is

  20. The effect of sublethal injury by heating, freezing, drying and gamma-radiation on the duration of the lag phase of Salmonella typhimurium

    International Nuclear Information System (INIS)

    Mackey, B.M.; Derrick, C.M.

    1982-01-01

    The duration of the lag phase of Salmonella typhimurium surviving heat, freezing, drying and gamma-radiation was used to indicate the time needed to repair sublethal injury. Following equivalent lethal treatments, heat and freeze-injured cells needed longer to repair than those injured by drying or gamma-radiation. Measurement of repair on membrane filters showed that in a heat-injured population having a lag time of 9 h, some individual cells needed up to 14 h to recover maximum tolerance to 3% NaCl. (author)

  1. EROD activity and stable isotopes in seabirds to disentangle marine food web contamination after the Prestige oil spill

    Energy Technology Data Exchange (ETDEWEB)

    Velando, Alberto, E-mail: avelando@uvigo.e [Departamento de Ecoloxia e Bioloxia Animal, Facultade de Ciencias, Universidade de Vigo, Campus As Lagoas, 36310 Vigo (Spain); Munilla, Ignacio [Departamento de Botanica, Facultade de Farmacia, Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Lopez-Alonso, Marta [Departamento de Patoloxia Animal, Facultade de Veterinaria, Universidade de Santiago de Compostela, Lugo (Spain); Freire, Juan [Grupo de Recursos Marinos y Pesquerias Universidade da Coruna, A Coruna (Spain); Perez, Cristobal [Departamento de Ecoloxia e Bioloxia Animal, Facultade de Ciencias, Universidade de Vigo, Campus As Lagoas, 36310 Vigo (Spain)

    2010-05-15

    In this study, we measured via surgical sampling hepatic EROD activity in yellow-legged gulls from oiled and unoiled colonies, 17 months after the Prestige oil spill. We also analyzed stable isotope composition in feathers of the biopsied gulls, in an attempt to monitor oil incorporation into marine food web. We found that yellow-legged gulls in oiled colonies were being exposed to remnant oil as shown by hepatic EROD activity levels. EROD activity was related to feeding habits of individual gulls with apparent consequences on delayed lethality. Capture-recapture analysis of biopsied gulls suggests that the surgery technique did not affect gull survival, giving support to this technique as a monitoring tool for oil exposure assessment. Our study highlights the combination of different veterinary, toxicological and ecological methodologies as a useful approach for the monitoring of exposure to remnant oil after a large oil spill. - Two years after Prestige oil spill, seabirds were exposed to remnant oil related to their feeding habits with consequences on delayed lethality.

  2. EROD activity and stable isotopes in seabirds to disentangle marine food web contamination after the Prestige oil spill

    International Nuclear Information System (INIS)

    Velando, Alberto; Munilla, Ignacio; Lopez-Alonso, Marta; Freire, Juan; Perez, Cristobal

    2010-01-01

    In this study, we measured via surgical sampling hepatic EROD activity in yellow-legged gulls from oiled and unoiled colonies, 17 months after the Prestige oil spill. We also analyzed stable isotope composition in feathers of the biopsied gulls, in an attempt to monitor oil incorporation into marine food web. We found that yellow-legged gulls in oiled colonies were being exposed to remnant oil as shown by hepatic EROD activity levels. EROD activity was related to feeding habits of individual gulls with apparent consequences on delayed lethality. Capture-recapture analysis of biopsied gulls suggests that the surgery technique did not affect gull survival, giving support to this technique as a monitoring tool for oil exposure assessment. Our study highlights the combination of different veterinary, toxicological and ecological methodologies as a useful approach for the monitoring of exposure to remnant oil after a large oil spill. - Two years after Prestige oil spill, seabirds were exposed to remnant oil related to their feeding habits with consequences on delayed lethality.

  3. Erodibility of surface-mine spoil banks in southeastern Ohio : an approximation

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, C D; Studlick, J R.J.

    1979-07-01

    Measurements of accumulated sediment in inter-bank basins of unreclaimed strip mines determined the average annual site loss from unvegetated, 18-year-old spoil banks. Assuming that the universal soil loss equation (USLE) can be used to estimate sediment yield from strip mine slopes, the topographic factor in the USLE was determined in 2 ways, and values for erodibility well calculated. The technique is applicable to unreclaimed mines where inter-bank basins trap all slope-derived sediment.

  4. Bond Stability of a Universal Adhesive System to Eroded/Abraded Dentin After Deproteinization.

    Science.gov (United States)

    Augusto, M G; Torres, Crg; Pucci, C R; Schlueter, N; Borges, A B

    Erosive/abrasive challenges can potentially compromise bonding to dentin. Aiming to improve the quality and stability of bonding to this substrate, this study investigated the combined effect of erosion and toothbrush abrasion on the microtensile bond strength (μTBS) stability to dentin using a universal adhesive system in total and self-etching modes, associated or not associated with deproteinization. Bovine dentin specimens were divided into five groups according to the organic matrix condition (n=20): control (C); erosion (E); erosion + abrasion (EA); erosion + sodium hypochlorite (EH); erosion + abrasion + sodium hypochlorite (EAH). The groups were further divided (n=10) according to the mode of application (total or self-etching) of a universal adhesive. After the bonding procedure, composite blocks were built up, and the samples were cut to obtain sticks for μTBS testing. For each specimen, one-half of the sticks was immediately tested, and the other one-half was tested after artificial aging (5000 thermocycles, 5°C and 55°C). Three-way analysis of variance (α=5%) showed a significant difference for the triple interaction ( p=0.0007). Higher μTBS means were obtained for the EH and EAH groups compared with the E and EA groups. The control group showed immediate μTBS values similar to that of the E and EA groups for both bond strategies. Erosion and erosion/abrasion did not significantly influence the immediate μTBS to dentin. Artificial aging reduced μTBS values for the groups C, E, and EA using the total-etching mode. Deproteinization maintained the bond stability to artificially aged eroded and eroded/abraded dentin.

  5. In Vitro Evaluation of Sub-Lethal Concentrations of Plant-Derived Antifungal Compounds on FUSARIA Growth and Mycotoxin Production

    Directory of Open Access Journals (Sweden)

    Caterina Morcia

    2017-07-01

    Full Text Available Phytopathogenic fungi can lead to significant cereal yield losses, also producing mycotoxins dangerous for human and animal health. The fungal control based on the use of synthetic fungicides can be complemented by "green" methods for crop protection, based on the use of natural products. In this frame, the antifungal activities of bergamot and lemon essential oils and of five natural compounds recurrent in essential oils (citronellal, citral, cinnamaldehyde, cuminaldehyde and limonene have been evaluated against three species of mycotoxigenic fungi (Fusarium sporotrichioides, F. graminearum and F. langsethiae responsible for Fusarium Head Blight in small-grain cereals. The natural products concentrations effective for reducing or inhibiting the in vitro fungal growth were determined for each fungal species and the following scale of potency was found: cinnamaldehyde > cuminaldehyde > citral > citronellal > bergamot oil > limonene > lemon oil. Moreover, the in vitro mycotoxin productions of the three Fusaria strains exposed to sub-lethal concentrations of the seven products was evaluated. The three fungal species showed variability in response to the treatments, both in terms of inhibition of mycelial growth and in terms of modulation of mycotoxin production that can be enhanced by sub-lethal concentrations of some natural products. This last finding must be taken into account in the frame of an open field application of some plant-derived fungicides.

  6. A PEDOTRANSFER FUNCTION FOR ESTIMATING THE SOIL ERODIBILITY FACTOR IN SICILY

    Directory of Open Access Journals (Sweden)

    Vincenzo Bagarello

    2009-09-01

    Full Text Available The soil erodibility factor, K, of the Universal Soil Loss Equation (USLE is a simple descriptor of the soil susceptibility to rill and interrill erosion. The original procedure for determining K needs a knowledge of soil particle size distribution (PSD, soil organic matter, OM, content, and soil structure and permeability characteristics. However, OM data are often missing and soil structure and permeability are not easily evaluated in regional analyses. The objective of this investigation was to develop a pedotransfer function (PTF for estimating the K factor of the USLE in Sicily (south Italy using only soil textural data. The nomograph soil erodibility factor and its associated first approximation, K’, were determined at 471 sampling points distributed throughout the island of Sicily. Two existing relationships for estimating K on the basis of the measured geometric mean particle diameter were initially tested. Then, two alternative PTFs for estimating K’ and K, respectively, on the basis of the measured PSD were derived. Testing analysis showed that the K estimate by the proposed PTF (eq.11, which was characterized by a Nash-Suttcliffe efficiency index, NSEI, varying between 0.68 and 0.76, depending on the considered data set, was appreciably more accurate than the one obtained by other existing equations, yielding NSEI values varying between 0.21 and 0.32.

  7. Crop Performance and Soil Properties in Two Artificially-Eroded Soils in North-Central Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Izaurralde, R Cesar C.; Malhi, S. S.; Nyborg, M.; Solberg, E. D.; Quiroga Jakas, Maria C.

    2006-09-01

    Field experiments were conducted from 1991 to 1995 at Josephburg (Orthic Black Chernozem, Typic Cryoboroll) and Cooking Lake (Orthic Gray Luvisol, Typic Cryoboralf), Alberta, to determine impact of topsoil removal on selected soil properties, N-mineralization potential and crop yield, and effectiveness of various amendments for restoring the productivity of eroded soils. The simulated-erosion levels were established in the autumn of 1990 by removing 20 cm topsoil in 5-cm depth increments. The four amendments were: control, addition of 5 cm of topsoil, fertilizers to supply 100 kg N ha-1 and 20 kg P ha-1, and cattle manure at 75 Mg ha-1. Topsoil and manure were applied once in the autumn of 1990, while fertilizers were applied annually from 1991 to 1995. Available N and P, total C, N and P, and N-mineralization potential decreased, while bulk density increased with increasing depth of topsoil removal. Tiller number, plant height, spike density, thousand kernel weight, and leaf area index decreased with simulated erosion. Grain yield reductions due to simulated soil erosion were either linear or curvilinear functions of nutrient removal. Application of N and P fertilizers and manure improved grain yield and reduced the impact of yield loss due to erosion. Return of 5 cm of topsoil also increased grain yield, but to a lesser extent than manure or fertilizers. Grain yields were maximized when fertilizers were also applied to organic amendment treatments. In conclusion, the findings suggest the importance of integrated use of organic amendments and chemical fertilizers for best crop yields on severely-eroded soils.

  8. Protein synthesis and sublethal damage repair in synchronized CHO cells

    International Nuclear Information System (INIS)

    Yezzi, M.J.; Tobias, C.A.; Blakely, E.A.

    1984-01-01

    The authors have previously reported that the split dose survival response to x-rays of asynchronous CHO-TSH1 cells is reduced if the cells are held at 40 0 C,a temperature that inhibits protein synthesis, for 2 hours before the first dose and during a 2-hour interval between doses. In conjunction with the survival experiments on asynchronous cells, the authors also examined the DNA rejoining ability in split dose studies with and without inhibition of protein synthesis. The results of these experiments suggest that inhibition of protein synthesis affects a pool of proteins that are necessary for the correct expression of the DNA, although they do not appear to be involved in rejoining DNA breaks. They have extended this work to the study of cells synchronized in G1 phase (2 hour post-mitosis) and S phase (10 hour post-mitosis). Autoradiographic analyses, using 3H-TdR pulse labeling, demonstrated that a delay in the progression of each synchronized cell population occurs after inhibition of protein synthesis. Data are reported on the effects of inhibition of protein synthesis on the ability of G1 and S phase cells to repair sublethal damage

  9. Turbidity current hydraulics and sediment deposition in erodible sinuous channels: Laboratory experiments and numerical simulations

    NARCIS (Netherlands)

    Janocko, M.; Cartigny, M.J.B.; Nemec, W.; Hansen, E.W.M.

    2013-01-01

    This study explores the relationship between the hydraulics of turbidity currents in erodible sinuous channels and the resulting intra-channel sediment depocentres (channel bars). Four factors are considered to exert critical control on sedimentation in sinuous submarine channels: (1) the

  10. Hepatic regeneration after sublethal partial liver irradiation in cirrhotic rats

    International Nuclear Information System (INIS)

    Gu Ke; Lai Songtao; Ma Ningyi; Zhao Jiandong; Ren Zhigang; Wang Jian; Liu Jin; Jiang Guoliang

    2011-01-01

    Our previous animal study had demonstrated that partial liver irradiation (IR) could stimulate regeneration in the protected liver, which supported the measurements adopted in radiotherapy planning for hepatocellular carcinoma. The purpose of this present study is to investigate whether cirrhotic liver repopulation could be triggered by partial liver IR. The cirrhosis was induced by thioacetamide (TAA) in rats. After cirrhosis establishment, TAA was withdrawn. In Experiment 1, only right-half liver was irradiated with single doses of 5 Gy, 10 Gy and 15 Gy, respectively. In Experiment 2, right-half liver was irradiated to 15 Gy, and the left-half to 2.5 Gy, 5 Gy and 7.5 Gy, respectively. The regeneration endpoints, including liver index (LI); mitotic index (MI); liver proliferation index (LPI); proliferating cell nuclear antigen-labeling index (PCNA-LI); serum hepatic growth factor (HGF), vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-α and interleukin (IL)-6, were evaluated on 0 day, 30-day, 60-day, 90-day, 120-day and 150-day after IR. Serum and in situ TGF-β1 were also measured. In both experimental groups, the IR injuries were sublethal, inducing no more than 9% animal deaths. Upon TAA withdrawal, hepatic regeneration decelerated in the controls. In Experiment 1 except for LI, all other regeneration parameters were significantly higher than those in controls for both right-half and left-half livers. In Experiment 2 all regeneration parameters were also higher compared with those in controls for both half livers. Serum HGF and VEGF were increased compared with that of controls. Both unirradiated and low dose-irradiated cirrhotic liver were able to regenerate triggered by sublethal partial liver IR and higher doses and IR to both halves liver triggered a more enhanced regeneration. (author)

  11. Physiological stress and ethanol accumulation in tree stems and woody tissues at sublethal temperatures from fire

    Science.gov (United States)

    Rick G. Kelsey; Douglas J. Westlind

    2017-01-01

    The lethal temperature limit is 60 degrees Celsius (°C) for plant tissues, including trees, with lower temperatures causing heat stress. As fire injury increases on tree stems, there is an accompanying rise in tissue ethanol concentrations, physiologically linked to impaired mitochondrial oxidative phosphorylation energy production. We theorize that sublethal tissue...

  12. Sublethal effects of a metal contamination due to uranium mine tailings in the three-spined stickleback (Gasterosteus aculeatus L.). Implication in the susceptibility to a biological stress

    International Nuclear Information System (INIS)

    Le Guernic, Antoine

    2015-01-01

    Uranium extraction has resulted in a remobilization of this actinide into mine surrounding ecosystems. Uses of metal salts during mining site rehabilitation, and the natural presence of metals have increased the metal contamination in hydro systems submitted to mine tailings. In situ experiments were conducted in two former French uranium mining sites. Three-spined stickleback caging was used to determine the sublethal effects of this metal mixture on this freshwater fish, as well as its effects on fish susceptibility to a sudden biological stress. This pollution, characterised by higher metal concentrations (especially for uranium), has led to an oxidative stress in sticklebacks visible through several bio-markers, and other effects dependent on the study site. The polymetallic contamination has modified the stickleback responses to the biological stress, by preventing their phagocytic and antioxidant responses. This work has reinforced the interest of the caging technique during environmental studies and that of immuno-markers in a multi-bio-marker approach. (author)

  13. Lethal/sublethal responses of Daphnia magna to acute norfloxacin contamination and changes in phytoplankton-zooplankton interactions induced by this antibiotic

    Science.gov (United States)

    Pan, Ying; Yan, Shi-Wei; Li, Ruo-Zhu; Hu, Yi-Wen; Chang, Xue-Xiu

    2017-01-01

    Although the well-known antibiotic norfloxacin (NOR) is recognized as an important environmental pollutant, little is known about its impacts on ecological processes, particularly on species interactions. In this paper, we quantified Daphnia magna (Crustacea, Cladocera) responses in mortality rate at lethal NOR concentrations (0, 25, 50, 100, 200, 300 and 400 mg L-1), and in heartbeat rate, swimming behavior and feeding rate (on the green alga Chlorella pyrenoidosa) at sublethal NOR concentrations (0, 25, 50 and 100 mg L-1) to determine the effects of this antibiotic in plankton systems. In 96-h-long lethal experiment, mortality rates of D. magna increased significantly with increasing NOR concentration and exposure time. In sublethal experiments, heartbeat rate decreased, while time ratio of vertical to horizontal swimming (TVH) and the duration of quiescence increased in D. magna individuals exposed to increasing NOR concentrations after 4 and 12 h of exposure. These collectively led to decreases in both average swimming ability and feeding rate, consistent with the positive relationship between average swimming ability and feeding rate. Overall, results indicate that, by affecting zooplankton heartbeat rate and behavior, NOR decreased feeding efficiency of D. magna even at low doses, therefore, it might seriously compromise ecosystem health and function.

  14. Analysis of eroded bovine teeth through laser speckle imaging

    Science.gov (United States)

    Koshoji, Nelson H.; Bussadori, Sandra K.; Bortoletto, Carolina C.; Oliveira, Marcelo T.; Prates, Renato A.; Deana, Alessandro M.

    2015-02-01

    Dental erosion is a non-carious lesion that causes progressive tooth wear of structure through chemical processes that do not involve bacterial action. Its origin is related to eating habits or systemic diseases involving tooth contact with substances that pose a very low pH. This work demonstrates a new methodology to quantify the erosion by coherent light scattering of tooth surface. This technique shows a correlation between acid etch duration and laser speckle contrast map (LASCA). The experimental groups presented a relative contrast between eroded and sound tissue of 17.8(45)%, 23.4 (68)% 39.2 (40)% and 44.3 (30)%, for 10 min, 20 min, 30 min and 40 min of acid etching, respectively.

  15. Predictive model for local scour downstream of hydrokinetic turbines in erodible channels

    Science.gov (United States)

    Musa, Mirko; Heisel, Michael; Guala, Michele

    2018-02-01

    A modeling framework is derived to predict the scour induced by marine hydrokinetic turbines installed on fluvial or tidal erodible bed surfaces. Following recent advances in bridge scour formulation, the phenomenological theory of turbulence is applied to describe the flow structures that dictate the equilibrium scour depth condition at the turbine base. Using scaling arguments, we link the turbine operating conditions to the flow structures and scour depth through the drag force exerted by the device on the flow. The resulting theoretical model predicts scour depth using dimensionless parameters and considers two potential scenarios depending on the proximity of the turbine rotor to the erodible bed. The model is validated at the laboratory scale with experimental data comprising the two sediment mobility regimes (clear water and live bed), different turbine configurations, hydraulic settings, bed material compositions, and migrating bedform types. The present work provides future developers of flow energy conversion technologies with a physics-based predictive formula for local scour depth beneficial to feasibility studies and anchoring system design. A potential prototype-scale deployment in a large sandy river is also considered with our model to quantify how the expected scour depth varies as a function of the flow discharge and rotor diameter.

  16. Sub-lethal toxicity of chlorpyrifos on Common carp, Cyprinus carpio (Linnaeus, 1758: Biochemical response

    Directory of Open Access Journals (Sweden)

    Mahdi Banaee

    2014-01-01

    Full Text Available Chlorpyrifos, an organophosphate pesticide, is widely used to control pests in agriculture farms and orchards of fruit trees. In this study, the fish were exposed to sub-lethal concentrations of chlorpyrifos which were determined based on numerical value of 96 h LC50. Blood was sampled after 10, 20 and 30 days and biochemical parameters including glucose, total protein, albumin, globulin, triglyceride and cholesterol levels, and aspartate aminotransferase (AST, alanine aminotransferase (ALT, lactate dehydrogenase (LDH, creatine kinase (CK, alkaline phosphatase (ALP and acetylcholinsetrase (AChE activities were measured. Behavioral changes in the fish were also recorded during the experiment. Unbalanced swimming, swimming in the surface water and hyperglycemia, increased blood triglyceride, and increased levels of AST, LDH and CK activities as well as decreased levels of AChE activity were important changes that were observed in the specimens exposed to chlorpyrifos during experimental periods. The most important alterations in the blood biochemical parameters were measured in the specimens exposed to 40 µg/L chlorpyrifos on the 20th and 30th day of the trial. In conclusion, results of the present study indicated that exposure to sub-lethal concentrations of chlorpyrifos as low as 40 µg/L may cause biochemical and behavioral changes in Cyprinus carpio.

  17. A single exposure to a sublethal pediocin concentration initiates a resistance-associated temporal cell envelope and general stress response in Listeria monocytogenes

    DEFF Research Database (Denmark)

    Laursen, Martin Frederik; Bahl, Martin Iain; Licht, Tine Rask

    2015-01-01

    was to determine if exposure to sublethal concentrations of pediocin-containing Lactobacillus plantarum WHE 92 supernatant could prime L. monocytogenes for resistance. By transcriptomic analysis, we found two, 55 and 539 genes differentially expressed after 10, 60 and 180 min of exposure to L. plantarum WHE 92...... resistant than wild types to L. plantarum WHE 92 supernatant. LisRK, SigB and SigL regulation and genes associated with resistance are involved in the temporal adaptive response to pediocin and all three regulatory systems affect pediocin resistance. Thus, a single exposure to a sublethal pediocin...

  18. Exposure to Sub-lethal 2,4-Dichlorophenoxyacetic Acid Arrests Cell Division and Alters Cell Surface Properties in Escherichia coli

    Science.gov (United States)

    Bhat, Supriya V.; Kamencic, Belma; Körnig, André; Shahina, Zinnat; Dahms, Tanya E. S.

    2018-01-01

    Escherichia coli is a robust, easily adaptable and culturable bacterium in vitro, and a model bacterium for studying the impact of xenobiotics in the environment. We have used correlative atomic force – laser scanning confocal microscopy (AFM-LSCM) to characterize the mechanisms of cellular response to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). One of the most extensively used herbicides world-wide, 2,4-D is known to cause hazardous effects in diverse non-target organisms. Sub-lethal concentrations of 2,4-D caused DNA damage in E. coli WM1074 during short exposure periods which increased significantly over time. In response to 2,4-D, FtsZ and FtsA relocalized within seconds, coinciding with the complete inhibition of cell septation and cell elongation. Exposure to 2,4-D also resulted in increased activation of the SOS response. Changes to cell division were accompanied by concomitant changes to surface roughness, elasticity and adhesion in a time-dependent manner. This is the first study describing the mechanistic details of 2,4-D at sub-lethal levels in bacteria. Our study suggests that 2,4-D arrests E. coli cell division within seconds after exposure by disrupting the divisome complex, facilitated by dissipation of membrane potential. Over longer exposures, 2,4-D causes filamentation as a result of an SOS response to oxidative stress induced DNA damage. PMID:29472899

  19. Detailed monitoring of a small but recovering population reveals sublethal effects of disease and unexpected interactions with supplemental feeding.

    Science.gov (United States)

    Tollington, Simon; Greenwood, Andrew; Jones, Carl G; Hoeck, Paquita; Chowrimootoo, Aurélie; Smith, Donal; Richards, Heather; Tatayah, Vikash; Groombridge, Jim J

    2015-07-01

    Infectious diseases are widely recognized to have substantial impact on wildlife populations. These impacts are sometimes exacerbated in small endangered populations, and therefore, the success of conservation reintroductions to aid the recovery of such species can be seriously threatened by outbreaks of infectious disease. Intensive management strategies associated with conservation reintroductions can further compound these negative effects in such populations. Exploring the sublethal effects of disease outbreaks among natural populations is challenging and requires longitudinal, individual life-history data on patterns of reproductive success and other indicators of individual fitness. Long-term monitoring data concerning detailed reproductive information of the reintroduced Mauritius parakeet (Psittacula echo) population collected before, during and after a disease outbreak was investigated. Deleterious effects of an outbreak of beak and feather disease virus (BFDV) were revealed on hatch success, but these effects were remarkably short-lived and disproportionately associated with breeding pairs which took supplemental food. Individual BFDV infection status was not predicted by any genetic, environmental or conservation management factors and was not associated with any of our measures of immune function, perhaps suggesting immunological impairment. Experimental immunostimulation using the PHA (phytohaemagglutinin assay) challenge technique did, however, provoke a significant cellular immune response. We illustrate the resilience of this bottlenecked and once critically endangered, island-endemic species to an epidemic outbreak of BFDV and highlight the value of systematic monitoring in revealing inconspicuous but nonetheless substantial ecological interactions. Our study demonstrates that the emergence of such an infectious disease in a population ordinarily associated with increased susceptibility does not necessarily lead to deleterious impacts on population

  20. EROD induction by environmental contaminants in avian embryo livers

    Energy Technology Data Exchange (ETDEWEB)

    Brunstroem, B.; Halldin, K. [Department of Environmental Toxicology, Uppsala University, Norbyvaegen 18A SE-752 36, Uppsala (Sweden)

    1998-11-01

    The CYP1A (EROD)-inducing potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3minutes or feet,4,4minutes or feet,5-pentachlorobiphenyl (PCB126) and benzo(k)fluoranthene (B(k)F) were studied in avian embryo livers. TCDD and PCB126 proved to be much more potent as inducers in the chicken than in the other species examined. This finding is consistent with a considerably higher sensitivity of the chicken compared with a number of other avian species to the embryotoxic effects of these compounds. Furthermore, the relative potencies of the tested Ah receptor agonists as CYP1A inducers differed substantially between species. B(k)F and PCB126 showed similar induction potencies in domestic duck embryos, whereas PCB126 is much more potent than B(k)F in the chicken. Also, the potency of PCB126,relative to that of TCDD, was much lower in quail embryo liver in vitro than in chicken embryo liver. Thus, there are large interspecific differences in birds in the sensitivity to CYP1A inducers and furthermore, the relative potencies of these compounds may differ substantially between species. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  1. EROD induction by environmental contaminants in avian embryo livers

    International Nuclear Information System (INIS)

    Brunstroem, B.; Halldin, K.

    1998-01-01

    The CYP1A (EROD)-inducing potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3minutes or feet,4,4minutes or feet,5-pentachlorobiphenyl (PCB126) and benzo(k)fluoranthene (B(k)F) were studied in avian embryo livers. TCDD and PCB126 proved to be much more potent as inducers in the chicken than in the other species examined. This finding is consistent with a considerably higher sensitivity of the chicken compared with a number of other avian species to the embryotoxic effects of these compounds. Furthermore, the relative potencies of the tested Ah receptor agonists as CYP1A inducers differed substantially between species. B(k)F and PCB126 showed similar induction potencies in domestic duck embryos, whereas PCB126 is much more potent than B(k)F in the chicken. Also, the potency of PCB126, relative to that of TCDD, was much lower in quail embryo liver in vitro than in chicken embryo liver. Thus, there are large interspecific differences in birds in the sensitivity to CYP1A inducers and furthermore, the relative potencies of these compounds may differ substantially between species. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  2. The involvement of IL-17A in the murine response to sub-lethal inhalational infection with Francisella tularensis.

    Directory of Open Access Journals (Sweden)

    Gal Markel

    2010-06-01

    Full Text Available Francisella tularensis is an intercellular bacterium often causing fatal disease when inhaled. Previous reports have underlined the role of cell-mediated immunity and IFNgamma in the host response to Francisella tularensis infection.Here we provide evidence for the involvement of IL-17A in host defense to inhalational tularemia, using a mouse model of intranasal infection with the Live Vaccine Strain (LVS. We demonstrate the kinetics of IL-17A production in lavage fluids of infected lungs and identify the IL-17A-producing lymphocytes as pulmonary gammadelta and Th17 cells. The peak of IL-17A production appears early during sub-lethal infection, it precedes the peak of immune activation and the nadir of the disease, and then subsides subsequently. Exogenous airway administration of IL-17A or of IL-23 had a limited yet consistent effect of delaying the onset of death from a lethal dose of LVS, implying that IL-17A may be involved in restraining the infection. The protective role for IL-17A was directly demonstrated by in vivo neutralization of IL-17A. Administration of anti IL-17A antibodies concomitantly to a sub-lethal airway infection with 0.1xLD(50 resulted in a fatal disease.In summary, these data characterize the involvement and underline the protective key role of the IL-17A axis in the lungs from inhalational tularemia.

  3. Influence of UVB radiation on the lethal and sublethal toxicity of dispersed crude oil to planktonic copepod nauplii.

    Science.gov (United States)

    Almeda, Rodrigo; Harvey, Tracy E; Connelly, Tara L; Baca, Sarah; Buskey, Edward J

    2016-06-01

    Toxic effects of petroleum to marine zooplankton have been generally investigated using dissolved petroleum hydrocarbons and in the absence of sunlight. In this study, we determined the influence of natural ultraviolet B (UVB) radiation on the lethal and sublethal toxicity of dispersed crude oil to naupliar stages of the planktonic copepods Acartia tonsa, Temora turbinata and Pseudodiaptomus pelagicus. Low concentrations of dispersed crude oil (1 μL L(-1)) caused a significant reduction in survival, growth and swimming activity of copepod nauplii after 48 h of exposure. UVB radiation increased toxicity of dispersed crude oil by 1.3-3.8 times, depending on the experiment and measured variables. Ingestion of crude oil droplets may increase photoenhanced toxicity of crude oil to copepod nauplii by enhancing photosensitization. Photoenhanced sublethal toxicity was significantly higher when T. turbinata nauplii were exposed to dispersant-treated oil than crude oil alone, suggesting that chemical dispersion of crude oil may promote photoenhanced toxicity to marine zooplankton. Our results demonstrate that acute exposure to concentrations of dispersed crude oil and dispersant (Corexit 9500) commonly found in the sea after oil spills are highly toxic to copepod nauplii and that natural levels of UVB radiation substantially increase the toxicity of crude oil to these planktonic organisms. Overall, this study emphasizes the importance of considering sunlight in petroleum toxicological studies and models to better estimate the impact of crude oil spills on marine zooplankton. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Behavioral responses of the estuarine calanoid copepod Eurytemora affinis to sub-lethal concentrations of waterborne pollutants

    International Nuclear Information System (INIS)

    Michalec, François-Gaël; Holzner, Markus; Menu, Dominique; Hwang, Jiang-Shiou; Souissi, Sami

    2013-01-01

    Highlights: •We studied the effects of sub-lethal exposure to pollutants on Eurytemora affinis swimming behavior. •Nonylphenol, cadmium and polycyclic aromatic hydrocarbons caused hyperactivity. •Effects were observable within 30 min of exposure and persisted during a depuration period. •The response resembles an escape reaction allowing copepods to evade stressful conditions. -- Abstract: Estuarine waters contain a variety of chemicals which affect to various extents the behavior of aquatic organisms. Little is known, however, on the behavioral response of copepods. The present study shows the results of laboratory experiments investigating the immediate effects of sub-lethal concentrations of three commonly found contaminants on the three-dimensional swimming behavior of the estuarine calanoid copepod Eurytemora affinis. Nonylphenol at 2 μg L −1 , cadmium at 45 ng L −1 and a mixture of low to medium molecular weight polycyclic aromatic hydrocarbons at 40 ng L −1 all affected the swimming behavior of E. affinis adults, increasing both swimming speed and activity. In most cases, effects were observable within 30 min of exposure and persisted or faded during a period of depuration in uncontaminated water of similar duration. In ovigerous females exposed to Cd and PAHs, effects appeared to be more pronounced during the depuration period, suggesting that carrying ovisacs may impair recovery. We quantified differences in the distribution of swimming speed values by considering the relative frequencies of periods of break, slow and fast swimming and we observed a trend toward faster movements in the presence of pollutants. The degree of trajectory complexity, estimated through their fractal dimension, was unaffected by pollutants. Since both narcotic and non-narcotic pollutants induced hyperactivity, our results suggest that changes in behavior after a short-term exposure may be independent of the general mode of action of the chemicals. The increase in

  5. Behavioral responses of the estuarine calanoid copepod Eurytemora affinis to sub-lethal concentrations of waterborne pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Michalec, François-Gaël [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France); National Taiwan Ocean University, Institute of Marine Biology, Keelung, Taiwan, ROC (China); Holzner, Markus [Institute of Environmental Engineering, ETH Zürich (Switzerland); Menu, Dominique [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France); Hwang, Jiang-Shiou [National Taiwan Ocean University, Institute of Marine Biology, Keelung, Taiwan, ROC (China); Souissi, Sami, E-mail: sami.souissi@univ-lille1.fr [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France)

    2013-08-15

    Highlights: •We studied the effects of sub-lethal exposure to pollutants on Eurytemora affinis swimming behavior. •Nonylphenol, cadmium and polycyclic aromatic hydrocarbons caused hyperactivity. •Effects were observable within 30 min of exposure and persisted during a depuration period. •The response resembles an escape reaction allowing copepods to evade stressful conditions. -- Abstract: Estuarine waters contain a variety of chemicals which affect to various extents the behavior of aquatic organisms. Little is known, however, on the behavioral response of copepods. The present study shows the results of laboratory experiments investigating the immediate effects of sub-lethal concentrations of three commonly found contaminants on the three-dimensional swimming behavior of the estuarine calanoid copepod Eurytemora affinis. Nonylphenol at 2 μg L{sup −1}, cadmium at 45 ng L{sup −1} and a mixture of low to medium molecular weight polycyclic aromatic hydrocarbons at 40 ng L{sup −1} all affected the swimming behavior of E. affinis adults, increasing both swimming speed and activity. In most cases, effects were observable within 30 min of exposure and persisted or faded during a period of depuration in uncontaminated water of similar duration. In ovigerous females exposed to Cd and PAHs, effects appeared to be more pronounced during the depuration period, suggesting that carrying ovisacs may impair recovery. We quantified differences in the distribution of swimming speed values by considering the relative frequencies of periods of break, slow and fast swimming and we observed a trend toward faster movements in the presence of pollutants. The degree of trajectory complexity, estimated through their fractal dimension, was unaffected by pollutants. Since both narcotic and non-narcotic pollutants induced hyperactivity, our results suggest that changes in behavior after a short-term exposure may be independent of the general mode of action of the chemicals. The

  6. Analysis of persistent changes to γ-aminobutyric acid receptor gene expression in Plutella xylostella subjected to sublethal amounts of spinosad.

    Science.gov (United States)

    Yin, X-H; Wu, Q-J; Zhang, Y-J; Long, Y-H; Wu, X-M; Li, R-Y; Wang, M; Tian, X-L; Jiao, X-G

    2016-07-25

    A multi-generational approach was used to investigate the persistent effects of a sub-lethal dose of spinosad in Plutella xylostella. The susceptibility of various sub-populations of P. xylostella to spinosad and the effects of the insecticide on the gene expression of γ-aminobutyric acid receptor (GABAR) were determined. The results of a leaf dip bioassay showed that the sensitivity of P. xylostella to spinosad decreased across generations. The sub-strains had been previously selected based on a determined LC25 of spinosad. Considering that GABA-gated chloride channels are the primary targets of spinosad, the cDNA of P. xylostella was used to clone GABARα by using reverse transcription-polymerase chain reaction (RT-PCR). The mature peptide cDNA was 1477-bp long and contained a 1449-bp open reading frame encoding a protein of 483 amino acids. The resulting amino acid sequence was used to generate a neighbor-joining dendrogram, and homology search was conducted using NCBI BLAST. The protein had high similarity with the known GABAR sequence from P. xylostella. Subsequent semi-quantitative RT-PCR and real-time PCR analyses indicated that the GABAR transcript levels in the spinosad-resistant strain (RR, 145.82-fold) and in Sub1 strain (selected with LC25 spinosad for one generation) were the highest, followed by those in the spinosad-susceptible strain, the Sub10 strain (selected for ten generations), and the Sub5 strain (selected for five generations). This multi-generational study found significant correlations between spinosad susceptibility and GABAR gene expression, providing insights into the long-term effects of sub-lethal insecticide exposure and its potential to lead to the development of insecticide-resistant insect populations.

  7. Acute exposure to a sublethal dose of imidacloprid and coumaphos enhances olfactory learning and memory in the honeybee Apis mellifera.

    Science.gov (United States)

    Williamson, Sally M; Baker, Daniel D; Wright, Geraldine A

    2013-06-01

    The decline of honeybees and other pollinating insects is a current cause for concern. A major factor implicated in their decline is exposure to agricultural chemicals, in particular the neonicotinoid insecticides such as imidacloprid. Honeybees are also subjected to additional chemical exposure when beekeepers treat hives with acaricides to combat the mite Varroa destructor. Here, we assess the effects of acute sublethal doses of the neonicotinoid imidacloprid, and the organophosphate acaricide coumaphos, on honey bee learning and memory. Imidacloprid had little effect on performance in a six-trial olfactory conditioning assay, while coumaphos caused a modest impairment. We report a surprising lack of additive adverse effects when both compounds were administered simultaneously, which instead produced a modest improvement in learning and memory.

  8. A statistical model for horizontal mass flux of erodible soil

    International Nuclear Information System (INIS)

    Babiker, A.G.A.G.; Eltayeb, I.A.; Hassan, M.H.A.

    1986-11-01

    It is shown that the mass flux of erodible soil transported horizontally by a statistically distributed wind flow has a statistical distribution. Explicit expression for the probability density function, p.d.f., of the flux is derived for the case in which the wind speed has a Weibull distribution. The statistical distribution for a mass flux characterized by a generalized Bagnold formula is found to be Weibull for the case of zero threshold speed. Analytic and numerical values for the average horizontal mass flux of soil are obtained for various values of wind parameters, by evaluating the first moment of the flux density function. (author)

  9. Tritium recycling and inventory in eroded debris of plasma-facing materials

    International Nuclear Information System (INIS)

    Hassanein, A.

    1999-01-01

    Damage to plasma-facing components (PFCs) and structural materials due to loss of plasma confinement in magnetic fusion reactors remains one of the most serious concerns for safe, successful, and reliable tokamak operation. High erosion losses due to surface vaporization, spallation, and melt-layer splashing are expected during such an event. The eroded debris and dust of the PFCs, including trapped tritium, will be contained on the walls or within the reactor chamber therefore, they can significantly influence plasma behavior and tritium inventory during subsequent operations. Tritium containment and behavior in PFCS and in the dust and debris is an important factor in evaluating and choosing the ideal plasma-facing materials (PFMs). Tritium buildup and release in the debris of candidate materials is influenced by the effect of material porosity on diffusion and retention processes. These processes have strong nonlinear behavior due to temperature, volubility, and existing trap sites. A realistic model must therefore account for the nonlinear and multidimensional effects of tritium diffusion in the porous-redeposited and neutron-irradiated materials. A tritium-transport computer model, TRAPS (Tritium Accumulation in Porous Structure), was developed and used to evaluate and predict the kinetics of tritium transport in porous media. This model is coupled with the TRICS (Tritium In Compound Systems) code that was developed to study the effect of surface erosion during normal and abnormal operations on tritium behavior in PFCS

  10. Contaminated soil phytoremediation by Cyperus laxus Lam. cytochrome p450 EROD-activity induced by hydrocarbons in roots.

    Science.gov (United States)

    López-Martínez, S; Gallegos-Martínez, M E; Pérez-Flores, L J; Gutiérrez-Rojas, M

    2008-01-01

    Laboratory and greenhouse experiments with Cyperus laxus Lam were conducted to determine the rate and extent of phytoremediation and the effect of hydrocarbons on the cytochrome P450 EROD (7-ethoxyresorufin-O-deethylase) enzymatic activity in roots. Plants were cultivated on hydrocarbon-contaminated soil (HCS) and spiked perlite. Phytoremediation was evaluated using 6.5 kg HCS (173 +/- 15 mg total petroleum hydrocarbons [TPH] g(-1) of dry soil) pots at different moisture contents; the average removal rate was 3.46-0.25 mg TPH g(-1) dry soil month(-1) and 48% was removed when moisture was kept at 60%. The aromatic hydrocarbon fraction was the mostly removed, 60%; aliphatic, 51%; and polar 24% after 24-month experiments. In unplanted pots, TPH concentration did not exhibit significant differences with respect to the initial concentration. We confirmed that the presence of hydrocarbons induced ERODactivity up to 6.5-fold. Moreover, short-term experiments (up to 13 d) with spiked perlite demonstrated that two EROD activities in roots contributed to the total detected; 60% was found in the cytosolic and 40% in the microsomal fraction. To our knowledge, this is the first work that tries to build links between the hydrocarbon-inducible character of ERODactivity in roots and the phytoremediation ability of C. laxus in highly contaminated soils.

  11. Eroding students' rural motivation: first do no harm?

    Science.gov (United States)

    Hurst, Samia

    2014-01-01

    Migration of health professionals is one of the drivers of vast inequalities in access to healthcare, as medical graduates tend to move away from both poorer countries and rural areas. One of the central ethical problems raised in attempting to alleviate these inequalities is the tension between the healthcare needs of under-served patients and the rights of medical graduates to choose their place of work and specialty. If medical graduates had greater motivation to work in under-served rural areas, this tension would decrease accordingly. Medical schools have a duty to avoid eroding existing motivation for such training and practice. This duty has practical implications. Medical students' motivation regarding their choice of specialty changes during medical training, turning them away from choices such as primary care and rural practice towards more highly specialised, more hospital based specialties. Although students may be victims of a number of biases in the initial assessment, this is unlikely to be the whole story. Students' priorities are likely to change based on their admiration for specialist role models and the visibility of the financial and non-financial rewards attached to these specialties. Students may also have a false expectation upon admission that they will be proficient in rural medicine on graduation, and change their mind once they realise the limits of their skills in that area. Although the measures required to reverse this effect currently lack a solid evidence base, they are plausible and supported by the available data.

  12. Making sense of nickel accumulation and sub-lethal toxic effects in saline waters: Fate and effects of nickel in the green crab, Carcinus maenas.

    Science.gov (United States)

    Blewett, Tamzin A; Glover, Chris N; Fehsenfeld, Sandra; Lawrence, Michael J; Niyogi, Som; Goss, Greg G; Wood, Chris M

    2015-07-01

    In freshwater, invertebrates nickel (Ni) is considered an ionoregulatory toxicant, but its mechanism of toxicity in marine settings, and how this varies with salinity, is poorly understood. This study investigated Ni accumulation and physiological mechanisms of sub-lethal Ni toxicity in the euryhaline green crab Carcinus maenas. Male crabs were exposed to 8.2μg/L (the US EPA chronic criterion concentration for salt waters) of waterborne Ni (radiolabelled with (63)Ni) at three different salinities, 20%, 60% and 100% SW for 24h. Whole body Ni accumulation in 20% SW was 3-5 fold greater than in 60% or 100% SW, and >80% of accumulated Ni was in the carapace at all salinities. Ni also accumulated in posterior gill 8, which showed a higher accumulation in 20% SW than in other salinities, a pattern also seen at higher exposure concentrations of Ni (500 and 3000μg/L). Gill perfusion experiments revealed that Ni was taken up by both anterior and posterior gills, but in 20% SW the posterior gill 8, which performs ionoregulatory functions, accumulated more Ni than the anterior gill 5, which primarily has a respiratory function. The sub-lethal consequences of Ni exposure were investigated by placing crabs in Ni concentrations of 8.2, 500, and 3000μg/L at 20, 60 or 100% SW for 24h. In 20% SW, haemolymph Ca levels were significantly decreased by exposure to Ni concentrations of 8.2μg/L or higher, whereas Na concentrations were depressed only at 3000μg/L. Na(+)/K(+)-ATPase activity was inhibited at both 500 and 3000μg/L in gill 8, but only in 20% SW. Haemolymph K, Mg, and osmolality were unaffected throughout, though all varied with salinity in the expected fashion. These data suggest that Ni impacts ionoregulatory function in the green crab, in a gill- and salinity-dependent manner. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Assessment of Ground Water Quality in and around Gobichettipalayam Town Erode District, Tamilnadu

    OpenAIRE

    P. N. Palanisamy; A. Geetha; M. Sujatha; P. Sivakumar; K. Karunakaran

    2007-01-01

    Ground water samples collected from different localities in and around Gobichettipalayam town, Erode District, Tamil Nadu were analyzed for their physico- chemical characteristics. This analysis result was compared with the WHO & ICMR standards of drinking water quality parameters with the following water quality parameters namely pH, Electrical conductivity, CN-, Cl-, SO42-, Na+, K+, Ca & Mg in CaCO3 equivalents, phenolphthalein alkalinity, hydroxide alkalinity, carbonate alkalinity, bicarbo...

  14. Proteomic analysis of differentiating neuroblastoma cells treated with sub-lethal neurite inhibitory concentrations of diazinon: Identification of novel biomarkers of effect

    International Nuclear Information System (INIS)

    Harris, W.; Sachana, M.; Flaskos, J.; Hargreaves, A.J.

    2009-01-01

    In previous work we showed that sub-lethal levels of diazinon inhibited neurite outgrowth in differentiating N2a neuroblastoma cells. Western blotting analysis targeted at proteins involved in axon growth and stress responses, revealed that such exposure led to a reduction in the levels of neurofilament heavy chain, microtubule associated protein 1 B (MAP 1B) and HSP-70. The aim of this study was to apply the approach of 2 dimensional polyacrylamide gel electrophoresis and mass spectrometry to identify novel biomarkers of effect. A number of proteins were found to be up-regulated compared to the control on silver-stained gels. These were classified in to 3 main groups of proteins: cytosolic factors, chaperones and the actin-binding protein cofilin, all of which are involved in cell differentiation, survival or metabolism. The changes observed for cofilin were further confirmed by quantitative Western blotting analysis with anti-actin and anti-cofilin antibodies. Indirect immunofluorescence staining with the same antibodies indicated that the microfilament network was disrupted in diazinon-treated cells. Our data suggest that microfilament organisation is disrupted by diazinon exposure, which may be related to increased cofilin expression.

  15. Graphene oxide significantly inhibits cell growth at sublethal concentrations by causing extracellular iron deficiency.

    Science.gov (United States)

    Yu, Qilin; Zhang, Bing; Li, Jianrong; Du, Tingting; Yi, Xiao; Li, Mingchun; Chen, Wei; Alvarez, Pedro J J

    Graphene oxide (GO)-based materials are increasingly being used in medical materials and consumer products. However, their sublethal effects on biological systems are poorly understood. Here, we report that GO (at 10 to 160 mg/L) induced significant inhibitory effects on the growth of different unicellular organisms, including eukaryotes (i.e. Saccharomyces cerevisiae, Candida albicans, and Komagataella pastoris) and prokaryotes (Pseudomonas fluorescens). Growth inhibition could not be explained by commonly reported cytotoxicity mechanisms such as plasma membrane damage or oxidative stress. Based on transcriptomic analysis and measurement of extra- and intracellular iron concentrations, we show that the inhibitory effect of GO was mainly attributable to iron deficiency caused by binding to the O-functional groups of GO, which sequestered iron and disrupted iron-related physiological and metabolic processes. This inhibitory mechanism was corroborated with supplementary experiments, where adding bathophenanthroline disulfonate-an iron chelating agent-to the culture medium exerted similar inhibition, whereas removing surface O-functional groups of GO decreased iron sequestration and significantly alleviated the inhibitory effect. These findings highlight a potential indirect detrimental effect of nanomaterials (i.e. scavenging of critical nutrients), and encourage research on potential biomedical applications of GO-based materials to sequester iron and enhance treatment of iron-dependent diseases such as cancer and some pathogenic infections.

  16. Normal and sublethally irradiated stem and granulocyte progenitor cell regeneration in an in vivo culture system. The cellular response to humoral factors released through the action of cyclophosphamide

    International Nuclear Information System (INIS)

    MacVittie, T.

    1977-01-01

    The in vivo diffusion chamber (DC) method of marrow culture was used to determine if the injection of host mice with cyclophosphamide (CY) caused, through its cytoxic action, the release of a humoral factor(s) capable of initiating stem cell (CFU-s) and granulocyte-macrophage progenitor cell (CFU-c) proliferation. Host mice were injected with CY 1-4 days prior to 800 rad of 60 Co WBI and implantation of DCs containing normal or 400 rad sublethally irradiated (SLI) marrow cells. The greatest proliferative response within CFU-s and CFU-c populations occurred in those mice injected with CY 3 days prior to implant. The marked CFU-s and CFU-c regeneration was initiated during the initial 24 hr of culture in both normal and SLI marrow cells. Thereafter growth rates were approximately the same. SLI marrow, however, showed a greater response to the humoral effects of CY injection than did normal marrow. These data provided evidence that CY induced the release of a diffusible factor(s) capable of accelerating regeneration of normal and sublethally irradiated CFU-s and CFU-c, the magnitude of which was dependent upon the time elapsed between CY injected and implantation of DCs. The marked proliferative response of the SLI stem and progenitor cells to the humoral stimulation may be indicative of the heterogeneity of both CFU-s and CFU-c populations surviving sublethal radiation exposure. The target cells may have possessed a differential sensitivity to the factor(s) initiating cell proliferation

  17. Sublethal Exposure to Diatomaceous Earth Increases Net Fecundity of Flour Beetles (Tribolium confusum) by Inhibiting Egg Cannibalism

    Science.gov (United States)

    Shostak, Allen W.

    2014-01-01

    Population regulation results from an interplay of numerous intrinsic and external factors, and for many insects cannibalism is such a factor. This study confirms a previously-reported observation that sublethal exposure to the fossilized remains of diatoms (i.e. diatomaceous earth) increases net fecundity (eggs produced minus eggs destroyed/day) of flour beetles, Tribolium confusum. The aim was to experimentally test two non-mutually-exclusive ecological mechanisms potentially responsible for the increased net fecundity: higher egg production and lower egg cannibalism. Adult T. confusum were maintained at low or high density in medium containing sublethal (0–4%) diatomaceous earth. Net fecundity increased up to 2.1× control values during diatomaceous earth exposure, and returned to control levels following removal from diatomaceous earth. Cannibalism assays on adults showed that diatomaceous earth reduced the number of eggs produced to 0.7× control values at low density and to 0.8× controls at high density, and also reduced egg cannibalism rates of adults to as little as 0.4× control values, but at high density only. Diatomaceous earth also reduced cannibalism by larvae on eggs to 0.3× control values. So, while the presence of diatomaceous earth reduced egg production, net fecundity increased as a result of strong suppression of the normal egg cannibalism by adults and larvae that occurs at high beetle density. Undisturbed cultures containing sublethal diatomaceous earth concentrations reached higher population densities than diatomaceous earth-free controls. Cohort studies on survival from egg to adult indicated that this population increase was due largely to decreased egg cannibalism by adult females. This is the first report of inhibition of egg cannibalism by diatomaceous earth on larval or adult insects. The ability of diatomaceous earth to alter cannibalism behavior without causing mortality makes it an ideal investigative tool for cannibalism

  18. Acute, Sub-lethal Cyanide Poisoning in Mice is Ameliorated by Nitrite Alone: Complications Arising from Concomitant Administration of Nitrite and Thiosulfate as an Antidotal Combination

    Science.gov (United States)

    Cambal, Leah K.; Swanson, Megan R.; Yuan, Quan; Weitz, Andrew C.; Li, Hui-Hua; Pitt, Bruce R.; Pearce, Linda L.; Peterson, Jim

    2011-01-01

    Sodium nitrite alone is shown to ameliorate sub-lethal cyanide toxicity in mice when given from ~1 hour before until 20 minutes after the toxic dose as demonstrated by the recovery of righting ability. An optimum dose (12 mg/kg) was determined to significantly relieve cyanide toxicity (5.0 mg/kg) when administered to mice intraperitoneally. Nitrite so administered was shown to rapidly produce NO in the bloodsteam as judged by the dose dependent appearance of EPR signals attributable to nitrosylhemoglobin and methemoglobin. It is argued that antagonism of cyanide inhibition of cytochrome c oxidase by NO is the crucial antidotal activity rather than the methemoglobin-forming action of nitrite. Concomitant addition of sodium thiosulfate to nitrite-treated blood resulted in the detection of sulfidomethemoblobin by EPR spectroscopy. Sulfide is a product of thiosulfate hydrolysis and, like cyanide, is known to be a potent inhibitor of cytochrome c oxidase; the effects of the two inhibitors being essentially additive under standard assay conditions, rather than dominated by either one. The findings afford a plausible explanation for an observed detrimental effect in mice associated with the use of the standard nitrite-thiosulfate combination therapy at sub-lethal levels of cyanide intoxication. PMID:21534623

  19. Toxic effects of selenium and copper on the planarian, Dugesia dorotocephala

    Energy Technology Data Exchange (ETDEWEB)

    Rauscher, J.D.

    1988-01-01

    Aquatic toxicologists have become increasingly concerned with the effects of sublethal concentrations of toxicants on aquatic organisms. Sublethal effects of toxicants on freshwater invertebrates were reviewed. Selenium (Se) and copper (Cu) are both essential trace elements and toxicants. Se has been reported to alter the toxicity of heavy metals. Planarians, Dugesia dorotocephala, were used as test animals. The objectives of this study were to determine: (1) acute toxicity of Se on planarians and the effect of the number of planarians per test chamber, (2) interaction of the acute toxicity of Se and Cu on planarians, and (3) sublethal effects of Se and Cu on planarians.

  20. Acute, sublethal and combination effects of azadirachtin and Bacillus thuringiensis toxins on Helicoverpa armigera (Lepidoptera: Noctuidae) larvae.

    Science.gov (United States)

    Singh, G; Rup, P J; Koul, Opender

    2007-08-01

    The efficacy of neem (1500 ppm azadirachtin (AI)), Delfin WG, a biological insecticide based on selected strain of Bacillus thuringiensis Berliner (Bt) subspecies kurstaki, and Cry1Ac protein, either individually or in combination, were examined against first to fourth instar Helicoverpa armigera (Hübner) larvae. Using an oral administration method, various growth inhibitory concentrations (EC) and lethal concentrations (LC) were determined for each bioagent. Combinations of sublethal concentrations of Bt spray formulation with azadirachtin at EC50 or EC95 levels not only enhanced the toxicity, but also reduced the duration of action when used in a mixture. The LC20 and LC50 values for Cry1Ac toxin were 0.06 and 0.22 microg ml-1, respectively. Bt-azadirachtin combinations of LC50+EC20 and LC50+EC50 result in 100% mortality. The mortality also was significant in LC20+EC20 and LC20+EC50 mixtures. These studies imply that the combined action is not synergistic but complimentary, with azadirachtin particularly facilitating the action of Bt. The Bt spray-azadirachtin combination is more economical than combinations that involve isolating the toxic protein, as the Bt spray formulations can be combined in a spray mixture with neem. These combinations may be useful for controlling bollworm populations that have acquired resistance to Bt as they may not survive the effect of mixture. Azadirachtin may be useful as a means of reducing the endotoxin concentrations in a mixture, to promote increased economic savings and further reduce the probability of resistance development to either insect control agent.

  1. Land degradation assessment by geo-spatially modeling different soil erodibility equations in a semi-arid catchment.

    Science.gov (United States)

    Saygın, Selen Deviren; Basaran, Mustafa; Ozcan, Ali Ugur; Dolarslan, Melda; Timur, Ozgur Burhan; Yilman, F Ebru; Erpul, Gunay

    2011-09-01

    Land degradation by soil erosion is one of the most serious problems and environmental issues in many ecosystems of arid and semi-arid regions. Especially, the disturbed areas have greater soil detachability and transportability capacity. Evaluation of land degradation in terms of soil erodibility, by using geostatistical modeling, is vital to protect and reclaim susceptible areas. Soil erodibility, described as the ability of soils to resist erosion, can be measured either directly under natural or simulated rainfall conditions, or indirectly estimated by empirical regression models. This study compares three empirical equations used to determine the soil erodibility factor of revised universal soil loss equation prediction technology based on their geospatial performances in the semi-arid catchment of the Saraykoy II Irrigation Dam located in Cankiri, Turkey. A total of 311 geo-referenced soil samples were collected with irregular intervals from the top soil layer (0-10 cm). Geostatistical analysis was performed with the point values of each equation to determine its spatial pattern. Results showed that equations that used soil organic matter in combination with the soil particle size better agreed with the variations in land use and topography of the catchment than the one using only the particle size distribution. It is recommended that the equations which dynamically integrate soil intrinsic properties with land use, topography, and its influences on the local microclimates, could be successfully used to geospatially determine sites highly susceptible to water erosion, and therefore, to select the agricultural and bio-engineering control measures needed.

  2. Chloride and sulphate toxicity to Hydropsyche exocellata (Trichoptera, Hydropsychidae): Exploring intraspecific variation and sub-lethal endpoints.

    Science.gov (United States)

    Sala, Miquel; Faria, Melissa; Sarasúa, Ignacio; Barata, Carlos; Bonada, Núria; Brucet, Sandra; Llenas, Laia; Ponsá, Sergio; Prat, Narcís; Soares, Amadeu M V M; Cañedo-Arguelles, Miguel

    2016-10-01

    The rivers and streams of the world are becoming saltier due to human activities. In spite of the potential damage that salt pollution can cause on freshwater ecosystems, this is an issue that is currently poorly managed. Here we explored intraspecific differences in the sensitivity of freshwater fauna to two major ions (Cl(-) and SO4(2-)) using the net-spinning caddisfly Hydropsyche exocellata Dufour 1841 (Trichoptera, Hydropsychidae) as a model organism. We exposed H. exocellata to saline solutions (reaching a conductivity of 2.5mScm(-1)) with Cl(-):SO4(2-) ratios similar to those occurring in effluents coming from the meat, mining and paper industries, which release dissolved salts to rivers and streams in Spain. We used two different populations, coming from low and high conductivity streams. To assess toxicity, we measured sub-lethal endpoints: locomotion, symmetry of the food-capturing nets and oxidative stress biomarkers. According to biomarkers and net building, the population historically exposed to lower conductivities (B10) showed higher levels of stress than the population historically exposed to higher conductivities (L102). However, the differences between populations were not strong. For example, net symmetry was lower in the B10 than in the L102 only 48h after treatment was applied, and biomarkers showed a variety of responses, with no discernable pattern. Also, treatment effects were rather weak, i.e. only some endpoints, and in most cases only in the B10 population, showed a significant response to treatment. The lack of consistent differences between populations and treatments could be related to the high salt tolerance of H. exocellata, since both populations were collected from streams with relatively high conductivities. The sub-lethal effects tested in this study can offer an interesting and promising tool to monitor freshwater salinization by combining physiological and behavioural bioindicators. Copyright © 2016 Elsevier B.V. All rights

  3. The effect of postirradiation holding at 22 degrees C on the repair of sublethal, potentially lethal and potentially neoplastic transforming damage in gamma-irradiated HeLa x skin fibroblast human hybrid cells

    International Nuclear Information System (INIS)

    Redpath, J.L.; Antoniono, R.J.; Mendonca, M.S.; Sun, C.

    1994-01-01

    The effect of postirradiation holding at 22 degrees C on cell growth, progression of cells through the cell cycle, and the repair of sublethal, potentially lethal and potentially neoplastic transforming damage in γ-irradiated HeLa x skin fibroblast human hybrid cells has been examined. Cell growth and cell cycle progression were essentially stopped at this reduced temperature. Cell survival was dramatically reduced by holding confluent cultures for 6 h at 22 degrees C, as opposed to 37 degrees C, after 7.5 Gy γ radiation delivered at a rate of 2 Gy/min. Return of the cells to 37 degrees C for 6 h after holding at 22 degrees C did not result in increased survival. A similar effect was obtained when the cells were held at 22 degrees C between split-dose irradiation of log-phase cultures where no increase in survival was observed over a split-dose interval of 4 h. In this case a partial increase in survival was observed upon returning the cells to 37 degrees C for 3 h after holding at 22 degrees C for the first 3 h of the split-dose interval. Neoplastic transformation frequency was not enhanced by holding confluent cultures for 6 h at 22 degrees C after 7.5 Gy γ radiation. This is consistent with previous observations that misrepair of potentially neoplastic transforming damage already occurs at 37 degrees C. The overall results are interpreted in terms of the reduced temperature favoring misrepair, rather than inhibition of repair, of sublethal, potentially lethal and potentially transforming radiation damage. 24 refs., 5 figs., 3 tabs

  4. Radio-induced neuropathology: from early effects to late sequelae. Rat behavioural and metabolic studies after sublethal total body irradiation

    International Nuclear Information System (INIS)

    Martigne, A.P.

    2010-05-01

    The radioresistance dogma of Central Nervous System (CNS) is now obsolete. Recent progress in neuroscience allow us to reconsider the radiation-induced cognitive dysfunctions observed after radiation therapy or after a nuclear accident, and to devise appropriate diagnostic and therapeutic means. We have developed a Rat model to study the effects of total body irradiation at a sublethal dose (4.5 Gy). This leads to impaired learning and memory of a task being acquired during the first month - which is prevented by administration of a radioprotector (amifostine) - while it does not appear to affect retrograde memory. Early, an apoptotic wave occurs in the sub-ventricular zone, 5 to 9 hours after exposure, while neuro-genesis is suppressed. Two days after irradiation, the metabolic study conducted by NMR HRMAS (High Resolution Magic Angle Spinning) suggests the presence of cerebral oedema and the study of brain lipids in liquid NMR confirms the membrane damages (elevated cholesterol and phospholipids). The lipid profile is then normalized while a gliosis appears. Finally, 1 month post-irradiation, the elevation of GABA, an inhibitory neurotransmitter, in 2 separate brain structures, occurs simultaneously with a taurine decrease in the hippocampus that lasts 6 months. Our integrated model allows validating bio-markers measurable in vivo NMR spectroscopy - the next experimental stage - and testing new radiation-protective agents. (author)

  5. The transient response for different types of erodable surface thermocouples using finite element analysis

    Directory of Open Access Journals (Sweden)

    Mohammed Hussein

    2007-01-01

    Full Text Available The transient response of erodable surface thermocouples has been numerically assessed by using a two dimensional finite element analysis. Four types of base metal erodable surface thermocouples have been examined in this study, included type-K (alumel-chromel, type-E (chromel-constantan, type-T (copper-constantan, and type-J (iron-constantan with 50 mm thick- ness for each. The practical importance of these types of thermocouples is to be used in internal combustion engine studies and aerodynamics experiments. The step heat flux was applied at the surface of the thermocouple model. The heat flux from the measurements of the surface temperature can be commonly identified by assuming that the heat transfer within these devices is one-dimensional. The surface temperature histories at different positions along the thermocouple are presented. The normalized surface temperature histories at the center of the thermocouple for different types at different response time are also depicted. The thermocouple response to different heat flux variations were considered by using a square heat flux with 2 ms width, a sinusoidal surface heat flux variation width 10 ms period and repeated heat flux variation with 2 ms width. The present results demonstrate that the two dimensional transient heat conduction effects have a significant influence on the surface temperature history measurements made with these devices. It was observed that the surface temperature history and the transient response for thermocouple type-E are higher than that for other types due to the thermal properties of this thermocouple. It was concluded that the thermal properties of the surrounding material do have an impact, but the properties of the thermocouple and the insulation materials also make an important contribution to the net response.

  6. The immediate effectiveness of barley straw mulch in reducing soil erodibility and surface runoff generation in Mediterranean vineyards.

    Science.gov (United States)

    Prosdocimi, Massimo; Jordán, Antonio; Tarolli, Paolo; Keesstra, Saskia; Novara, Agata; Cerdà, Artemi

    2016-03-15

    Soil and water loss in agriculture is a major problem throughout the world, and especially in Mediterranean areas. Non-conservation agricultural practices have further aggravated the situation, especially in vineyards, which are affected by one of the highest rates of soil loss among cultivated lands. Therefore, it is necessary to find the right soil practices for more sustainable viticulture. In this regard, straw mulching has proven to be effective in other crop and fire affected soils, but, nonetheless, little research has been carried out in vineyards. This research tests the effect of barley straw mulching on soil erosion and surface runoff on vineyards in Eastern Spain where the soil and water losses are non-sustainable. An experiment was setup using rainfall simulation tests at 55 mm h(-1) over 1h on forty paired plots of 0.24 m(2): twenty bare and twenty straw covered. Straw cover varied from 48 to 90% with a median value of 59% as a result of the application of 75 g of straw per m(2). The use of straw mulch resulted in delayed ponding and runoff generation and, as a consequence, the median water loss decreased from 52.59 to 39.27% of the total rainfall. The straw cover reduced the median sediment concentration in runoff from 9.8 to 3.0 g L(-1) and the median total sediment detached from 70.34 to 15.62 g per experiment. The median soil erosion rate decreased from 2.81 to 0.63 Mg ha(-1)h(-1) due to the straw mulch protection. Straw mulch is very effective in reducing soil erodibility and surface runoff, and this benefit was achieved immediately after the application of the straw. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. An analysis of lethal and sublethal interactions among type I and type II pyrethroid pesticide mixtures using standard Hyalella azteca water column toxicity tests.

    Science.gov (United States)

    Hoffmann, Krista Callinan; Deanovic, Linda; Werner, Inge; Stillway, Marie; Fong, Stephanie; Teh, Swee

    2016-10-01

    A novel 2-tiered analytical approach was used to characterize and quantify interactions between type I and type II pyrethroids in Hyalella azteca using standardized water column toxicity tests. Bifenthrin, permethrin, cyfluthrin, and lambda-cyhalothrin were tested in all possible binary combinations across 6 experiments. All mixtures were analyzed for 4-d lethality, and 2 of the 6 mixtures (permethrin-bifenthrin and permethrin-cyfluthrin) were tested for subchronic 10-d lethality and sublethal effects on swimming motility and growth. Mixtures were initially analyzed for interactions using regression analyses, and subsequently compared with the additive models of concentration addition and independent action to further characterize mixture responses. Negative interactions (antagonistic) were significant in 2 of the 6 mixtures tested, including cyfluthrin-bifenthrin and cyfluthrin-permethrin, but only on the acute 4-d lethality endpoint. In both cases mixture responses fell between the additive models of concentration addition and independent action. All other mixtures were additive across 4-d lethality, and bifenthrin-permethrin and cyfluthrin-permethrin were also additive in terms of subchronic 10-d lethality and sublethal responses. Environ Toxicol Chem 2016;35:2542-2549. © 2016 SETAC. © 2016 SETAC.

  8. Risk assessment of PCDD/Fs levels in human tissues related to major food items based on chemical analyses and micro-EROD assay.

    Science.gov (United States)

    Tsang, H L; Wu, S C; Wong, C K C; Leung, C K M; Tao, S; Wong, M H

    2009-10-01

    Nine groups of food items (freshwater fish, marine fish, pork, chicken, chicken eggs, leafy, non-leafy vegetables, rice and flour) and three types of human samples (human milk, maternal serum and cord serum) were collected for the analysis of PCDD/Fs. Results of chemical analysis revealed PCDD/Fs concentrations (pg g(-1) fat) in the following ascending order: pork (0.289 pg g(-1) fat), grass carp (Ctenopharyngodon idellus) (freshwater fish) (0.407), golden thread (Nemipterus virgatus) (marine fish) (0.511), chicken (0.529), mandarin fish (Siniperca kneri) (marine fish) (0.535), chicken egg (0.552), and snubnose pompano (Trachinotus blochii) (marine fish) (1.219). The results of micro-EROD assay showed relatively higher PCDD/Fs levels in fish (2.65 pg g(-1) fat) when compared with pork (0.47), eggs (0.33), chicken (0.13), flour (0.07), vegetables (0.05 pg g(-1) wet wt) and rice (0.05). The estimated average daily intake of PCDD/Fs of 3.51 pg EROD-TEQ/kg bw/day was within the range of WHO Tolerable Daily Intake (1-4 pg WHO-TEQ/kg bw/day) and was higher than the Provisional Tolerable Daily Intake (PMTL) (70 pg for dioxins and dioxin-like PCBs) recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) [Joint FAO/WHO Expert Committee on Food Additives (JECFA), Summary and conclusions of the fifty-seventh meeting, JECFA, 2001.]. Nevertheless, the current findings were significantly lower than the TDI (14 pg WHO-TEQ/kg/bw/day) recommended by the Scientific Committee on Food of the Europe Commission [European Scientific Committee on Food (EU SCF), Opinions on the SCF on the risk assessment of dioxins and dioxin-like PCBs in food, 2000.]. However, it should be noted that micro-EROD assay overestimates the PCDD/Fs levels by 2 to 7 folds which may also amplify the PCDD/Fs levels accordingly. Although the levels of PCDD/Fs obtained from micro-EROD assay were much higher than those obtained by chemical analysis by 2 to 7 folds, it provides a cost-effective and

  9. Assessing the sublethal effects of in-river concentrations of parameters contributing to cumulative effects in the Athabasca river basin using a fathead minnow bioassay.

    Science.gov (United States)

    Squires, Allison J; Dubé, Monique G; Rozon-Ramilo, Lisa D

    2013-03-01

    The Athabasca River basin, located in Alberta, Canada, covers 157, 000 km(2) and holds significant cultural and economic importance. Recent research assessed changes in several water quality and quantity parameters that have changed both spatially (along the river continuum) and temporally (pre-development and present day) in the Athabasca River Basin. In particular, parameters such as salinity and dissolved sulphate have changed significantly across the Athabasca River mainstem over the past five decades. Further laboratory testing has linked concentrations of these parameters to changes in fathead minnow reproduction. Research is required to determine whether these changes observed in the laboratory can be applied to actual in-river conditions. The objectives of the present study were to twofold: assess changes in fathead minnow response metrics (i.e., condition, liver and gonad size, egg production, and gill histology) associated with increasing concentrations of salinity and dissolved sulphate and determine whether sublethal effect thresholds established in laboratory experiments correspond to actual in-river concentrations using water from the mouth and headwaters of the Athabasca River. Three dose-response experiments (NaCl, SO4, and water sampled from the mouth of the Athabasca River) were conducted at Jasper National Park, Alberta, Canada. Significant increases in mean eggs per female per day occurred at the 50% treatment for the mouth experiment and thresholds previously developed in the laboratory were verified. Copyright © 2012 SETAC.

  10. Numerical simulation of evolutionary erodible bedforms using the particle finite element method

    Science.gov (United States)

    Bravo, Rafael; Becker, Pablo; Ortiz, Pablo

    2017-07-01

    This paper presents a numerical strategy for the simulation of flows with evolutionary erodible boundaries. The fluid equations are fully resolved in 3D, while the sediment transport is modelled using the Exner equation and solved with an explicit Lagrangian procedure based on a fixed 2D mesh. Flow and sediment are coupled in geometry by deforming the fluid mesh in the vertical direction and in velocities with the experimental sediment flux computed using the Meyer Peter Müller model. A comparison with real experiments on channels is performed, giving good agreement.

  11. Quantifying the eroded volume of mercury-contaminated sediment using terrestrial laser scanning at Stocking Flat, Deer Creek, Nevada County, California, 2010–13

    Science.gov (United States)

    Howle, James F.; Alpers, Charles N.; Bawden, Gerald W.; Bond, Sandra

    2016-07-28

    High-resolution ground-based light detection and ranging (lidar), also known as terrestrial laser scanning, was used to quantify the volume of mercury-contaminated sediment eroded from a stream cutbank at Stocking Flat along Deer Creek in the Sierra Nevada foothills, about 3 kilometers west of Nevada City, California. Terrestrial laser scanning was used to collect sub-centimeter, three-dimensional images of the complex cutbank surface, which could not be mapped non-destructively or in sufficient detail with traditional surveying techniques.The stream cutbank, which is approximately 50 meters long and 8 meters high, was surveyed on four occasions: December 1, 2010; January 20, 2011; May 12, 2011; and February 4, 2013. Volumetric changes were determined between the sequential, three-dimensional lidar surveys. Volume was calculated by two methods, and the average value is reported. Between the first and second surveys (December 1, 2010, to January 20, 2011), a volume of 143 plus or minus 15 cubic meters of sediment was eroded from the cutbank and mobilized by Deer Creek. Between the second and third surveys (January 20, 2011, to May 12, 2011), a volume of 207 plus or minus 24 cubic meters of sediment was eroded from the cutbank and mobilized by the stream. Total volumetric change during the winter and spring of 2010–11 was 350 plus or minus 28 cubic meters. Between the third and fourth surveys (May 12, 2011, to February 4, 2013), the differencing of the three-dimensional lidar data indicated that a volume of 18 plus or minus 10 cubic meters of sediment was eroded from the cutbank. The total volume of sediment eroded from the cutbank between the first and fourth surveys was 368 plus or minus 30 cubic meters.

  12. Transmission electron microscopy study of Listeria monocytogenes serotype 1/2a cells exposed to sublethal heat stress and carvacrol

    Science.gov (United States)

    The objective of this study was to investigate the morphological changes that occurred in Listeria monocytogenes serotype 1/2a cells as visualized by transmission electron microscopy (TEM) after exposure to sublethal heat stress at 48°C for 60 min and in combination with lethal concentration of carv...

  13. Multibiomarker assessment of cerium dioxide nanoparticle (nCeO{sub 2}) sublethal effects on two freshwater invertebrates, Dreissena polymorpha and Gammarus roeseli

    Energy Technology Data Exchange (ETDEWEB)

    Garaud, M. [Université de Lorraine, CNRS UMR 7360, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Campus Bridoux, Rue du Général Delestraint, 57070 Metz (France); International Consortium for the Environmental Implications of Nanotechnology (iCEINT), Aix en Provence (France); Trapp, J.; Devin, S.; Cossu-Leguille, C.; Pain-Devin, S.; Felten, V. [Université de Lorraine, CNRS UMR 7360, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Campus Bridoux, Rue du Général Delestraint, 57070 Metz (France); Giamberini, L., E-mail: laure.giamberini@univ-lorraine.fr [Université de Lorraine, CNRS UMR 7360, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Campus Bridoux, Rue du Général Delestraint, 57070 Metz (France); International Consortium for the Environmental Implications of Nanotechnology (iCEINT), Aix en Provence (France)

    2015-01-15

    Highlights: • Gammarids and mussels both accumulated significant amount of waterborne nCeO{sub 2}. • nCeO{sub 2} decreased catalase, lysosomal system size and lipoperoxidation in mussels. • nCeO{sub 2} could exert antioxidant protecting activity in mussels. • In contrast with mussels, no effects of nCeO{sub 2} were observed on Gammarids. - Abstract: Cerium nanoparticles (nCeO{sub 2}) are widely used in everyday products, as fuel and paint additives. Meanwhile, very few studies on nCeO{sub 2} sublethal effects on aquatic organisms are available. We tried to fill this knowledge gap by investigating short-term effects of nCeO{sub 2} at environmentally realistic concentrations on two freshwater invertebrates; the amphipod Gammarus roeseli and the bivalve Dreissena polymorpha, using an integrated multibiomarker approach to detect early adverse effects of nCeO{sub 2} on organism biology. Differences in the behaviour of the organisms and of nanoparticles in the water column led to differential nCeO{sub 2} bioaccumulations, G. roeseli accumulating more cerium than D. polymorpha. Exposure to nCeO{sub 2} led to decreases in the size of the lysosomal system, catalase activity and lipoperoxidation in mussel digestive glands that could result from nCeO{sub 2} antioxidant properties, but also negatively impacted haemolymph ion concentrations. At the same time, no strong adverse effects of nCeO{sub 2} could be observed on G. roeseli. Further experiments will be necessary to confirm the absence of severe nCeO{sub 2} adverse effects in long-term environmentally realistic conditions.

  14. Kinetics of sublethal damage recovery in mouse lip mucosa comparing low and high-LET radiation

    International Nuclear Information System (INIS)

    Scalliet, P.; Landuyt, W.; Schueren, E. van der; Vynckier, S.; Wambersie, A.

    1989-01-01

    The effects of d(50)+Be neutrons on the lip mucosa in mice were investigated as a model of early effects. The biological endpoint eas the incidence of desquamation in the lower lip after selective irradiation of the snout of the animals. ED 50 (dose leading to desquamation in 50% of the animals) were calculated by probit analysis. Fractionated (two, four and ten fractions) and protracted (43.5, 11.5 and 0.88 Gy.h -1 ) irradiations have been carried out. Results were analysed using the mathematical method of Dale. An α/β of 39.6 Gy and a t 1/2 of recovery of sublethal damage of 47 min have been derived. These results have been compared to data previously obtained with cobalt-60 gamma rays. Using the same mathematical approach, and comparing similar fractionated and protracted experiments, an α/β of 7.4 Gy and a t 1/2 of recovery of 47 min have been calculated. There was no significant difference in the repair kinetics after irradiations with gamma rays or d(50)+Be neutrons. (orig.) [de

  15. Sublethal doses of neonicotinoid imidacloprid can interact with honey bee chemosensory protein 1 (CSP1) and inhibit its function.

    Science.gov (United States)

    Li, Hongliang; Tan, Jing; Song, Xinmi; Wu, Fan; Tang, Mingzhu; Hua, Qiyun; Zheng, Huoqing; Hu, Fuliang

    2017-04-29

    As a frequently used neonicotinoid insecticide, imidacloprid can impair the chemoreceptive behavior of honey bees even at sublethal doses, while the physiochemical mechanism has not been further revealed. Here, multiple fluorescence spectra, thermodynamic method, and molecular docking were used to study the interaction and the functional inhibition of imidacloprid to the recombinant CSP1 protein in Asian honey bee, Apis cerana. The results showed that the fluorescence intensity (λ em  = 332 nm) of CSP1 could be significantly quenched by imidacloprid in a dynamic mode. During the quenching process, ΔH > 0, ΔS > 0, indicating that the acting forces of imidacloprid with CSP1 are mainly hydrophobic interactions. Synchronous fluorescence showed that the fluorescence of CSP1 was mainly derived from tryptophan, and the hydrophobicity of tryptophan decreased with the increase of imidacloprid concentration. Molecular docking predicted the optimal pose and the amino acid composition of the binding process. Circular dichroism (CD) spectra showed that imidacloprid reduced the α-helix of CSP1 and caused the extension of the CSP1 peptide chain. In addition, the binding of CSP1 to floral scent β-ionone was inhibited by nearly 50% of the apparent association constant (K A ) in the presence of 0.28-2.53 ng/bee of imidacloprid, and the inhibition rate of nearly 95% at 3.75 ng/bee of imidacloprid at sublethal dose level. This study initially revealed the molecular physiochemical mechanism that sublethal doses of neonicotinoid still interact and inhibit the physiological function of the honey bees' chemoreceptive system. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Notochord in Tilapia nilotica Exposed to Sublethal Dose of Malathion, S[1, 2-Di(EthoxycarbonylEthyl] Dimethyl Phosphorothiolothionate

    Directory of Open Access Journals (Sweden)

    Edna Amparado

    1992-06-01

    Full Text Available Exposure of Tilapia nilotica embryos to sublethal dose of 1.0 ppm commercial grade malathion, S[1,2-di(ethoxycarbonylethyl] dimethyl phosphorothiolothionate from day-10 post fertilization resulted in notochordal aberrations. Pesticide-treated fishes exhibited constriction of the notochordal sheath, folding at the posterior sections and larger notochord than those of the control group.

  17. Metalloporphyrin Co(III)TMPyP ameliorates acute, sublethal cyanide toxicity in mice.

    Science.gov (United States)

    Benz, Oscar S; Yuan, Quan; Amoscato, Andrew A; Pearce, Linda L; Peterson, Jim

    2012-12-17

    The formation of Co(III)TMPyP(CN)(2) at pH 7.4 has been shown to be completely cooperative (α(H) = 2) with an association constant of 2.1 (±0.2) × 10(11). The kinetics were investigated by stopped-flow spectrophotometry and revealed a complicated net reaction exhibiting 4 phases at pH 7.4 under conditions where cyanide was in excess. The data suggest molecular HCN (rather than CN(-)) to be the attacking nucleophile around neutrality. The two slower phases do not seem to be present when cyanide is not in excess, and the other two phases have rates comparable to that observed for cobalamin, a known effective cyanide scavenger. Addition of bovine serum albumin (BSA) did not affect the cooperativity of cyanide binding to Co(III)TMPyP, only lowered the equilibrium constant slightly to 1.2 (±0.2) × 10(11) and had an insignificant effect on the observed rate. A sublethal mouse model was used to assess the effectiveness of Co(III)TMPyP as a potential cyanide antidote. The administration of Co(III)TMPyP to sodium cyanide intoxicated mice resulted in the time required for the surviving mice to right themselves from a supine position being significantly decreased (9 ± 2 min) compared to that of the controls (33 ± 2 min). All observations were consistent with the demonstrated antidotal activity of Co(III)TMPyP operating through a cyanide-binding (i.e., scavenging) mechanism.

  18. Repair of sublethal damage in mammalian cells irradiated at ultrahigh dose rates

    International Nuclear Information System (INIS)

    Gerweck, L.E.; Epp, E.R.; Michaels, H.B.; Ling, C.C.; Peterson, E.C.

    1979-01-01

    The lethal response of asynchronous Chinese hamster ovary (CHO) cells exposed to single and split doses of radiation at conventional or ultrahigh dose rates has been examined to determine whether repair of sublethal damage occurs in cells irradiated at ultrahigh dose rates. The high-intensity irradiations were performed with electrons delivered in single 3-nsec pulses from a 600-kV field emission source under medium-removed, thin-layer conditions. Conventional dose-rate experiments were done under identical thin-layer conditions with 50-kVp x rays, or under full-medium conditions with 280-kVp x rays. Oxygenated cells were irradiated and maintained at 22 to 24 0 C between exposures. Survival did not increase as the time between two doses of pulsed electrons increased from 0 to 4 min, indicating no evidence of fast repair. However, increased survival was observed when 30 to 90 min was allowed to elapse between the split doses. The half-time for maximum repair was approx. = 30 min irrespective of the exposure conditions and radiation modality used. Observed repair ratios increased from approx. = 2 to 4 as the single-dose surviving fraction decreased from 10 -2 to 5 x 10 -4 . Over this survival range the repair ratios, measured at the same value of surviving fraction, were independent of dose rate. The observed repair ratios imply that the shoulder regions of the nonfractionated x-ray and pulsed-electron survival curves were not completely restored between the split doses. However, the fraction of the shoulder restored between split doses of radiation was dose-rate-independent. It is concluded that sublethal damage can be repaired in oxygenated CHO cells irradiated at dose rates of the order of 10 11 rad/sec

  19. The Effect of A Single Sub-Lethal Dose of Whole Body Irradiation on the Small Intestine of Rats

    International Nuclear Information System (INIS)

    Al-Ramli, M. A.; Kubba, M. A.; Al-Bassam, L. S.; Belhaj, K.; Al-shawish, N. M.

    2007-01-01

    The effect of whole body radiation with a single sub-lethal dose at 4 Gy on rat small intestine was studied histologically and quantitatively. Irradiated animals were euthanized at 24 hours, 3, 7, 14, 21 and 28 days post- irradiation. Crypts of Leiberkuhn and peyer's patches were especially targeted by irradiation. The crypts showed severe cellular fragmentation in the germinal cellular compartments twenty Four hours after irradiation resulting in partial denudation of villi especially at their Tips. At three days, these cells resumed their proliferative activity with the appearance of unusually large numbers of mitotic figures. Cellular regeneration in the crypts and on the villous surface showed improvement with advancing time till day 28 when the villi had complete epithelial covering and the proliferative activity of the germinal cryptic cells returned to normal. The quantitative study included the measurement of about fifty villi at each time after irradiation. A significant decrease in villous length was noticed at twenty four hours post-irradiation compared to the control values. The length of villi plateaued at about this level till day twenty one when it slightly increased to reach a sub normal mean length on day 28. We concluded that whole body irradiation with a single dose at 4 Gy was enough to induce cryptic cellular necrosis with sloughing of epithelial villous columnar covering. This cellular damage was, however, sub- total since quick regenerative cellular activity was noticed three days post-irradiation. The decrease in the villous length paralleled the cryptic cellular damage whereas full recovery was not achieved despite obvious cellular regeneration.

  20. Linking sub-individual and supra-individual effects in Daphnia magna exposed to sub-lethal concentration of chlorpyrifos.

    Science.gov (United States)

    Ferrario, Claudia; Parolini, Marco; De Felice, Beatrice; Villa, Sara; Finizio, Antonio

    2018-04-01

    The main objective of the present study was to investigate possible links between sub-individual and supra-individual levels (i.e. population level) biomarkers in D. magna exposed to sublethal concentrations of the insecticide chlorpyrifos (CPF). To achieve the aim, 8-day old individuals were exposed for 96 h to two environmentally relevant concentrations of CPF (50 and 250 ng/L). Sub-individual level effects were investigated by measuring the activity of antioxidant (SOD, CAT, and GPx) and detoxifying (GST) enzymes, as well as by measuring the acetylcholinesterase (AChE) inhibition. In addition, the effects at supra-individual level were assessed by using a video-tracking system and analyzing changes in swimming capabilities (i.e. percentage of activity time, distance moved, and velocity). Our data have shown that daphnids exposed to both CPF concentrations were in a condition of stress which was highlighted by changes in both sub- and supra-individual biomarkers. Moreover, our results highlighted that the lowest tested CPF concentration did not modulate the antioxidant and detoxifying enzymes, whereas, an inhibition of AChE and a decrease of some parameters related to swimming behaviour (distance moved and velocity) were noted. On the contrary, significant changes in all the sub-individual biomarkers were measured at the highest tested concentration. In addition, organisms recovered the movement capability (distance moved) and also activate a mechanism of avoidance (increased swimming velocity). On the other hand, a reduction in the percent of active time was measured and this was attributed to the energy spent by organisms to activate antioxidant and detoxifying enzymes and the mechanism of avoidance. Based on these results, our study suggests the existence of a link between sub- and supra-individual levels, as the activation or non-activation in the antioxidant and detoxifying enzymes activities can led to different modifications of the swimming behaviour

  1. Deposition of eroded soil on terraced croplands in Minchet catchment, Ethiopian Highlands

    Directory of Open Access Journals (Sweden)

    Alemtsehay Subhatu

    2017-09-01

    Full Text Available In the Ethiopian Highlands, soil and water conservation practices are of utmost importance to conserve eroded soil and combat soil loss. This study provides detailed results on on-site sediment deposition and net soil loss in terraced croplands in a catchment in the sub-humid Ethiopian Highlands. Sediment deposition was measured on horse bean and maize fields during the crop growing seasons of 2014 and 2015. Measurements took place on observation plots on terraced cropland with varying spacing between terraces and varying slope gradients. Net soil loss, in this case the amount leaving the terraced cropland, was calculated by modelling the Universal Soil Loss Equation (USLE for the whole observation field and subtracting the measured sediment deposition. The study result showed about 8–11 t ha−1 sediment was deposited in the deposition zone of the terraced cropland, with greater sediment deposition on terraces with narrow spacing and steeper slope gradients. Sediment deposition was highest in July and August, and relatively low in September. Annual soil loss ranged from 32 to 37 t ha−1 in the terraced cropland of the study area. From the total soil loss in the crop growing season, about 54–74% sediment was deposited on the deposition zone of terraced crop fields. Implementation of soil and water conservation with narrow spacing, especially on the steep slopes of the sub-humid Ethiopian Highlands or other similar area, are thus highly recommended as they enable conservation of the eroded soil in the cropland.

  2. Cranium eroding sweat gland carcinoma. A case report

    International Nuclear Information System (INIS)

    Arslan, M.; Karadeniz, A. N.; Aksu, G.; Guveli, M.

    2005-01-01

    Background. Sweat gland carcinomas are rare tumors. Eccrine sweat gland carcinomas are also very rare, with only about 200 cases reported in the world literature and only one of them was eroding the cranium. Treatment modalities of these carcinomas are not well known. Case report. Our patient was 47 years old female. Since 1989, she was operated on six times because of the tumour relapses. After each operation, the pathological results were: sweat gland adenoma, sweat gland tumour, cylindroma, turban tumour, malign cylindiroma. That was her seventh relapse. On examination, a lesion of the size 10 x 6 cm was observed in the left parietal region. Computed tomography showed the lesion had the size of 11 x 5 cm, and was destroying the tabula externa, diploic region and tabula. The tumour was invading the dura and causing periost reaction. Surgery and postoperative radiotherapy treatment was planned because of malign transformation and risk of recurrence. Conclusions. Only one case with cranium erosion was reported in literature. In our case, also intracranial extension of the tumor was observed. (author)

  3. A Hydrodynamic and Sediment Transport Model for the Waipaoa Shelf, New Zealand: Sensitivity of Fluxes to Spatially-Varying Erodibility and Model Nesting

    Directory of Open Access Journals (Sweden)

    Julia M. Moriarty

    2014-04-01

    Full Text Available Numerical models can complement observations in investigations of marine sediment transport and depositional processes. A coupled hydrodynamic and sediment transport model was implemented for the Waipaoa River continental shelf offshore of the North Island of New Zealand, to complement a 13-month field campaign that collected seabed and hydrodynamic measurements. This paper described the formulations used within the model, and analyzed the sensitivity of sediment flux estimates to model nesting and seabed erodibility. Calculations were based on the Regional Ocean Modeling System—Community Sediment Transport Modeling System (ROMS-CSTMS, a primitive equation model using a finite difference solution to the equations for momentum and water mass conservation, and transport of salinity, temperature, and multiple classes of suspended sediment. The three-dimensional model resolved the complex bathymetry, bottom boundary layer, and river plume that impact sediment dispersal on this shelf, and accounted for processes including fluvial input, winds, waves, tides, and sediment resuspension. Nesting within a larger-scale, lower resolution hydrodynamic model stabilized model behavior during river floods and allowed large-scale shelf currents to impact sediment dispersal. To better represent observations showing that sediment erodibility decreased away from the river mouth, the seabed erosion rate parameter was reduced with water depth. This allowed the model to account for the observed spatial pattern of erodibility, though the model held the critical shear stress for erosion constant. Although the model neglected consolidation and swelling processes, use of a spatially-varying erodibility parameter significantly increased export of fluvial sediment from Poverty Bay to deeper areas of the shelf.

  4. Effect of sublethal doses of gamma radiation on DNA super helicity and survival of human fibroblasts

    International Nuclear Information System (INIS)

    Koceva-Chyla, A.

    1992-01-01

    Effect of sublethal doses of gamma radiation on cell survival and DNA super helicity in human fibroblasts was studied. Cell survival was estimated on the basis the basis of clonal growth of irradiated fibroblasts in monolayer culture in vitro. The nucleoid sedimentation technique was used to study ionizing radiation-induced DNA damage in vivo as well as to examine DNA super helicity. Increased concentrations of ethidium bromine (EB) were used to titrate the DNA super coiling response in non-irradiated cells. This response consisted of a relaxation phase (1-5 μg/ml EB) and rewinding phase (5-20 μg/ml EB). Observed biphasic dependence of sedimentation distance of nucleoid on the concentration of EB suggests the dye altered the amount of DNA super coiling in situ. The degree of DNA super coiling and thus the sedimentation rate of nucleoid in absence of EB was very sensitive to strand break induced in DNA by the doses of gamma radiation employed in the cell survival assay. Doses of 2-8 Gy of gamma radiation induced a dose -dependent reduction in the sedimentation of nucleoid. Loss of negative DNA super coiling was initially rapid (about 30% after the dose of 2 Gy) and then proceeded at a slower rate (about 35% and 48% after the doses of 4 Gy and 8 Gy respectively), indicating a significant relaxation of nucleoid structure at the doses of gamma radiation greater than 4 Gy, at which also significant decrease in fibroblasts survival occurred. Significant loss of negative DNA super coiling within the range of doses of gamma radiation resulting in significant decrease of cell survival suggests that destabilizing effect of radiation on DNA tertiary- and quaternary structures (extensive DNA breaks and relaxation of nucleonic super helicity) disturb normal functions and replications of genomic DNA, in consequence leading to a reproductive death of cells. Considering the sensitivity and simplicity of the method, the nucleoid sedimentation technique might be also a useful tool

  5. Sub-lethal effects of energy development on a migratory mammal—The enigma of North American pronghorn

    Directory of Open Access Journals (Sweden)

    Jon P. Beckmann

    2016-04-01

    (Pinedale Anticline Project Area [PAPA] and Jonah fields and other behavioral or ecological observations of sub-lethal effects, we failed to reject the null hypothesis that development is unrelated to parity in pronghorn biological responses. Studies intent on producing knowledge to assess whether energy development is inimical or not to ungulates will increasingly require appropriate time scales and understanding whether populations are below an expected food ceiling. Further, as with pronghorn in our study region, knowing if individuals are at the limits of their biological range (e.g. altitude where stressful winter conditions may mask impacts of development is important.

  6. Tracing the source of soil organic matter eroded from temperate forest catchments using carbon and nitrogen isotopes

    Science.gov (United States)

    Emma P. McCorkle; Asmeret Asefaw Berhe; Carolyn T. Hunsaker; Dale W. Johnson; Karis J. McFarlane; Marilyn L. Fogel; Stephen C. Hart

    2016-01-01

    Soil erosion continuously redistributes soil and associated soil organic matter (SOM) on the Earth's surface, with important implications for biogeochemical cycling of essential elements and terrestrial carbon sequestration. Despite the importance of soil erosion, surprisingly few studies have evaluated the sources of eroded carbon (C). We used natural abundance...

  7. Identification of water soluble and particle bound compounds causing sublethal toxic effects. A field study on sediments affected by a chlor-alkali industry

    International Nuclear Information System (INIS)

    Bosch, Carme; Olivares, Alba; Faria, Melissa; Navas, Jose M.; Olmo, Ivan del; Grimalt, Joan O.; Pina, Benjamin; Barata, Carlos

    2009-01-01

    A combination of cost effective sublethal Daphnia magna feeding tests, yeast- and cell culture-based bioassays and Toxicity Identification Evaluation (TIE) procedures was used to characterize toxic compounds within sediments collected in a river area under the influence of the effluents from a chlor-alkali industry (Ebro River, NE Spain). Tests were designed to measure and identify toxic compounds in the particulate and filtered water fractions of sediment elutriates. The combined use of bioassays responding to elutriates and dioxin-like compounds evidenced the existence of three major groups of hazardous contaminants in the most contaminated site: (A) metals such as cadmium and mercury bound to sediment fine particles that could be easily resuspended and moved downstream, (B) soluble compounds (presumably, lye) able to alkalinize water to toxic levels, and (C) organochlorine compounds with high dioxin-like activity. These results provided evidence that elutriate D. magna feeding responses can be used as surrogate assays for more tedious chronic whole sediment tests, and that the incorporation of such tests in sediment TIE procedures may improve the ability to identify the toxicity of particle-bound and water-soluble contaminants in sediments.

  8. Sublethal RNA Oxidation as a Mechanism for Neurodegenerative Disease

    Directory of Open Access Journals (Sweden)

    Mark A. Smith

    2008-05-01

    Full Text Available Although cellular RNA is subjected to the same oxidative insults as DNA and other cellular macromolecules, oxidative damage to RNA has not been a major focus in investigations of the biological consequences of free radical damage. In fact, because it is largely single-stranded and its bases lack the protection of hydrogen bonding and binding by specific proteins, RNA may be more susceptible to oxidative insults than is DNA. Oxidative damage to protein-coding RNA or non-coding RNA will, in turn, potentially cause errors in proteins and/or dysregulation of gene expression. While less lethal than mutations in the genome, such sublethal insults to cells might be associated with underlying mechanisms of several chronic diseases, including neurodegenerative disease. Recently, oxidative RNA damage has been described in several neurodegenerative diseases including Alzheimer disease, Parkinson disease, dementia with Lewy bodies, and prion diseases. Of particular interest, oxidative RNA damage can be demonstrated in vulnerable neurons early in disease, suggesting that RNA oxidation may actively contribute to the onset of the disease. An increasing body of evidence suggests that, mechanistically speaking, the detrimental effects of oxidative RNA damage to protein synthesis are attenuated, at least in part, by the existence of protective mechanisms that prevent the incorporation of the damaged ribonucleotides into the translational machinery. Further investigations aimed at understanding the processing mechanisms related to oxidative RNA damage and its consequences may provide significant insights into the pathogenesis of neurodegenerative and other degenerative diseases and lead to better therapeutic strategies.

  9. Sublethal effects of diazinon, fenitrothion and chlorpyrifos on the functional response of predatory bug, Andrallus spinidens Fabricius (Hem.: Pentatomidae in the laboratory conditions

    Directory of Open Access Journals (Sweden)

    Moloud GholamzadehChitgar

    2014-04-01

    Full Text Available The sublethal effects of diazinon, fenitrothion and chlorpyrifos on the functional response of predatory bug, Andrallus spinidens Fabricius (Hem.: Pentatomidae, a potential biological control agent, were studied on 5th-instar nymphs. The experiment was conducted in varying densities (2, 4, 8, 16, 32 and 64 of last instars larvae of Chilo suppressalis Walker (Lepidoptera: Pyralidae as prey at 25 ± 2 °C, 60% ± 10% relative humidity (RH and a photoperiod of 16:8 h (L: D. The results of logistic regressions revealed a type II functional response in the control and all insecticide treatments. Comparison of functional response curves revealed that tested insecticides markedly decreased the mean of preys consumed by A. spinidens. Among them, functional response curve of A. spinidens in chlorpyrifos treatment was significantly lower than the other treatments. In this study, application of insecticides caused a decrease in the attack rate and an increase in the handling time of exposed bugs compared with the control. The longest handling time (3.97 ± 0.62 and the lowest attack rate (0.023 ± 0.007 were observed in chlorpyrifos and fenitrothion treatments, respectively. The results suggested that the adverse effect of these insecticides on A. spinidens should be considered in integrated pest management programs (IPM.

  10. Metabolic responses of Eisenia fetida after sub-lethal exposure to organic contaminants with different toxic modes of action

    Energy Technology Data Exchange (ETDEWEB)

    McKelvie, Jennifer R.; Wolfe, David M.; Celejewski, Magda A. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada); Alaee, Mehran [Environment Canada, 867 Lakeshore Rd., P.O. Box 5050, Burlington, ON L7R 4A6 (Canada); Simpson, Andre J. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada); Simpson, Myrna J., E-mail: myrna.simpson@utoronto.ca [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada)

    2011-12-15

    Nuclear magnetic resonance (NMR) - based metabolomics has the potential to identify toxic responses of contaminants within a mixture in contaminated soil. This study evaluated the metabolic response of Eisenia fetida after exposure to an array of organic compounds to determine whether contaminant-specific responses could be identified. The compounds investigated in contact tests included: two pesticides (carbaryl and chlorpyrifos), three pharmaceuticals (carbamazephine, estrone and caffeine), two persistent organohalogens (Aroclor 1254 and PBDE 209) and two industrial compounds (nonylphenol and dimethyl phthalate). Control and contaminant-exposed metabolic profiles were distinguished using principal component analysis and potential contaminant-specific biomarkers of exposure were found for several contaminants. These results suggest that NMR-based metabolomics offers considerable promise for differentiating between the different toxic modes of action (MOA) associated with sub-lethal toxicity to earthworms. - Highlights: > NMR-based earthworm metabolomic analysis of the toxic mode of action of various environmental contaminants. > Organic chemicals with different toxic modes of action resulted in varied metabolomic responses for E. fetida. > NMR-based metabolomics differentiates between the different modes of action associated with sub-lethal toxicity. - {sup 1}H NMR metabolomics was used to identify potential biomarkers of organic contaminant exposure in Eisenia fetida earthworms.

  11. Measuring the Amount of Eroded Soil and Surface Runoff Water in the Field

    OpenAIRE

    Abdulfatah Faraj Aboufayed

    2013-01-01

    Water erosion is the most important problems of the soil in the Jabel Nefusa area located in northwest of Libya; therefore, erosion station had been established in the Faculty of Veterinary and dryfarming research Station, University of the Al-japel Al-gharbi in Zentan. The length of the station is 72.6 feet, 6 feet width and the percentage of its slope is 3%. The station were established to measure the amount of soil eroded and amount of surface water produced during the seasons 95/96 and 96...

  12. Dose-response tests and semi-field evaluation of lethal and sub-lethal effects of slow release pyriproxyfen granules (Sumilarv®0.5G) for the control of the malaria vectors Anopheles gambiae sensu lato.

    Science.gov (United States)

    Mbare, Oscar; Lindsay, Steven W; Fillinger, Ulrike

    2013-03-14

    Recently research has shown that larviciding can be an effective tool for integrated malaria vector control. Nevertheless, the uptake of this intervention has been hampered by the need to re-apply larvicides frequently. There is a need to explore persistent, environmentally friendly larvicides for malaria vector control to reduce intervention efforts and costs by reducing the frequency of application. In this study, the efficacy of a 0.5% pyriproxyfen granule (Surmilarv®0.5G, Sumitomo Chemicals) was assessed for the control of Anopheles gambiae sensu stricto and Anopheles arabiensis, the major malaria vectors in sub-Saharan Africa. Dose-response and standardized field tests were implemented following standard procedures of the World Health Organization's Pesticide Evaluation Scheme to determine: (i) the susceptibility of vectors to this formulation; (ii) the residual activity and appropriate retreatment schedule for field application; and, (iii) sub-lethal impacts on the number and viability of eggs laid by adults after exposure to Sumilarv®0.5G during larval development. Anopheles gambiae s.s. and An. arabiensis were highly susceptible to Sumilarv®0.5G. Estimated emergence inhibition (EI) values were very low and similar for both species. The minimum dosage that completely inhibited adult emergence was between 0.01-0.03 parts per million (ppm) active ingredient (ai). Compared to the untreated control, an application of 0.018 ppm ai prevented 85% (95% confidence interval (CI) 82%-88%) of adult emergence over six weeks under standardized field conditions. A fivefold increase in dosage of 0.09 ppm ai prevented 97% (95% CI 94%-98%) emergence. Significant sub-lethal effects were observed in the standardized field tests. Female An. gambiae s.s. that were exposed to 0.018 ppm ai as larvae laid 47% less eggs, and females exposed to 0.09 ppm ai laid 74% less eggs than females that were unexposed to the treatment. Furthermore, 77% of eggs laid by females exposed to 0

  13. Dose–response tests and semi-field evaluation of lethal and sub-lethal effects of slow release pyriproxyfen granules (Sumilarv®0.5G) for the control of the malaria vectors Anopheles gambiae sensu lato

    Science.gov (United States)

    2013-01-01

    Background Recently research has shown that larviciding can be an effective tool for integrated malaria vector control. Nevertheless, the uptake of this intervention has been hampered by the need to re-apply larvicides frequently. There is a need to explore persistent, environmentally friendly larvicides for malaria vector control to reduce intervention efforts and costs by reducing the frequency of application. In this study, the efficacy of a 0.5% pyriproxyfen granule (Surmilarv®0.5G, Sumitomo Chemicals) was assessed for the control of Anopheles gambiae sensu stricto and Anopheles arabiensis, the major malaria vectors in sub-Saharan Africa. Methods Dose–response and standardized field tests were implemented following standard procedures of the World Health Organization’s Pesticide Evaluation Scheme to determine: (i) the susceptibility of vectors to this formulation; (ii) the residual activity and appropriate retreatment schedule for field application; and, (iii) sub-lethal impacts on the number and viability of eggs laid by adults after exposure to Sumilarv®0.5G during larval development. Results Anopheles gambiae s.s. and An. arabiensis were highly susceptible to Sumilarv®0.5G. Estimated emergence inhibition (EI) values were very low and similar for both species. The minimum dosage that completely inhibited adult emergence was between 0.01-0.03 parts per million (ppm) active ingredient (ai). Compared to the untreated control, an application of 0.018 ppm ai prevented 85% (95% confidence interval (CI) 82%-88%) of adult emergence over six weeks under standardized field conditions. A fivefold increase in dosage of 0.09 ppm ai prevented 97% (95% CI 94%-98%) emergence. Significant sub-lethal effects were observed in the standardized field tests. Female An. gambiae s.s. that were exposed to 0.018 ppm ai as larvae laid 47% less eggs, and females exposed to 0.09 ppm ai laid 74% less eggs than females that were unexposed to the treatment. Furthermore, 77

  14. Role of protein synthesis in the repair of sublethal x-ray damage in a mutant Chinese hamster ovary cell line

    International Nuclear Information System (INIS)

    Yezzi, M.J.

    1985-01-01

    A temperature-sensitive mutant for protein synthesis, CHO-TSH1, was compared to the wild-type cell, CHO-SC1, in single- and split-radiation-dose schemes. When the cultures were incubated at 40 0 C for 2 hrs before a first dose and maintained at 40 0 C during a 2 hr dose fractionation interval, repair of radiation damage was reduced in the mutant compared to the wild type. These observations implied that a pool of proteins was involved in the repair of sublethal X-ray damage. The effect of diminished repair under conditions of inhibition of protein synthesis was found to be cell-cycle dependent in survival studies with synchronized mutant cell populations. Repair was found to be almost completely eliminated if the temperature sequence described above was applied in the middle of the DNA synthetic phase. Distinct perturbations in the cell-cycle progression were noted following heat alone or heat with radiation. A delay in the progression of synchronized G 1 -phase and S-phase cells was demonstrated autoradiographically after inhibition of protein synthesis. In addition, treated S-phase cells showed a transient increase in the percent labelled cells after the cells were returned to their normal growth temperature of 35 0 C. This observation was suggestive of an unusual pattern of DNA synthesis during the recovery period. Split-dose experiments were done using incubation with cycloheximide to chemically inhibit protein synthesis. Both the chemical and thermal inhibition of protein synthesis substantiate its necessity for the repair of sublethal damage

  15. Repair of potentially lethal and sublethal radiation damage in x-irradiated ascites tumor cells

    International Nuclear Information System (INIS)

    Tsuboi, Atsushi; Okamoto, Mieko; Tsuchiya, Takehiko.

    1985-01-01

    The ability of cells to repair cellular radiation damage during the growth of TMT-3 ascites tumor and the effect of host reaction on the repair ability were examined by using an in vitro assay of cell clonogenicity after in situ irradiation of tumor cells. In single-dose experiments, the repair of potentially lethal radiation damage (PLD) was observed in stationary phase cells (12-day tumor) of the unirradiated host, but not in exponential phase cells (3-day tumor) of the unirradiated host animals. However, if previously irradiated host animals were used, even the exponentially growing tumor cells showed repair of PLD. In two-dose experiments, the ability to repair sublethal radiation damage (SLD) in exponential phase tumor cells was less than that of stationary phase cells in the unirradiated host. In the pre-irradiated host, the extent of the repair in exponential phase cells was somewhat enhanced. These results suggest that irradiation of host animals might suppress a factor that inhibits repair, resulting in enhancement of the repair capability of tumor cells. (author)

  16. Workplace bullying erodes job and personal resources: between- and within-person perspectives.

    Science.gov (United States)

    Tuckey, Michelle R; Neall, Annabelle M

    2014-10-01

    Workplace bullying is a serious psychosocial occupational hazard. Despite a wealth of empirical study, research has rarely examined the mechanisms through which bullying has its negative effects. Accordingly, using both between- and within-person approaches, we investigated the erosion of job (Study 1) and personal (Study 2) resources following workplace bullying, mediated by the depletion of emotional energy. In Study 1, self-report survey data were collected from 221 retail workers at 2 time-points spaced 6 months apart. Structural equation modeling revealed that over time bullying depletes coworker support, partially mediated by emotional exhaustion. In Study 2, a 6-week diary was completed by a separate sample of 45 workers employed in various occupations. Within-person weekly variability in bullying exposure was 34%. Hierarchical linear modeling showed that weekly emotional exhaustion partially mediated the negative effects of weekly workplace bullying on both optimism and self-efficacy. The consistent pattern across both studies supports the idea of a resource loss process whereby exposure to bullying at work erodes job and personal resources by depleting energy. Future research should clarify the role of exhaustion in utilizing resources to respond to bullying, focus on predictors of within-person variability in bullying exposure, and more explicitly model the resource loss spiral following workplace bullying. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  17. Sublethal Effects of Imidacloprid on Honey Bee Colony Growth and Activity at Three Sites in the U.S.

    Science.gov (United States)

    Meikle, William G; Adamczyk, John J; Weiss, Milagra; Gregorc, Ales; Johnson, Don R; Stewart, Scott D; Zawislak, Jon; Carroll, Mark J; Lorenz, Gus M

    2016-01-01

    Imidacloprid is a neonicotinoid pesticide heavily used by the agricultural industry and shown to have negative impacts on honey bees above certain concentrations. We evaluated the effects of different imidacloprid concentrations in sugar syrup using cage and field studies, and across different environments. Honey bee colonies fed sublethal concentrations of imidicloprid (0, 5, 20 and 100 ppb) over 6 weeks in field trials at a desert site (Arizona), a site near intensive agriculture (Arkansas) and a site with little nearby agriculture but abundant natural forage (Mississippi) were monitored with respect to colony metrics, such as adult bee and brood population sizes, as well as pesticide residues. Hive weight and internal hive temperature were monitored continuously over two trials in Arizona. Colonies fed 100 ppb imidacloprid in Arizona had significantly lower adult bee populations, brood surface areas and average frame weights, and reduced temperature control, compared to colonies in one or more of the other treatment groups, and consumption rates of those colonies were lower compared to other colonies in Arizona and Arkansas, although no differences in capped brood or average frame weight were observed among treatments in Arkansas. At the Mississippi site, also rich in alternative forage, colonies fed 5 ppb imidacloprid had less capped brood than control colonies, but contamination of control colonies was detected. In contrast, significantly higher daily hive weight variability among colonies fed 5 ppb imidacloprid in Arizona suggested greater foraging activity during a nectar flow post treatment, than any other treatment group. Imidacloprid concentrations in stored honey corresponded well with the respective syrup concentrations fed to the colonies and remained stable within the hive for at least 7 months after the end of treatment.

  18. Restoring crop productivity of eroded lands through , integrated plant nutrient management (IPNM) for sustained production

    International Nuclear Information System (INIS)

    Bhatti, A.U.; Ali, S.

    2005-01-01

    Crop productivity of eroded lands is very poor due to removal of top fertile soil losing organic matter and plant nutrients, with consequent exposure of the sub-soil with poor fertility status. Crop productivity of such lands needs to be restored in order to help farmers feed many mouths because of increased population and high land pressure. Three field experiments were laid out at three sites, Thana, Malakand Agency; Kabal and Matta, Swat during 2003-2004 to study the effect of integrated plant nutrient management on the yield of wheat. The fertilizer treatments consisted of farmer's practice (60-45-0 kg N-P/sub 2/O/sub 5/-K/sub 2/O ha/sup -1/), recommended fertilizer rate (120-90-60 kg N-P/sub 2/O/sub 5/-K/sub 2/O ha/sup -l/ + 5 kg Zn ha/sup -1), and combined application of organic and inorganic sources of plant nutrients (FYM at the rate of 20 t ha/sup -1/ plus 60-90-60 kg N-P/sub 2/O/sub 5/-K/sub 2/O ha/sup -1/ + 5 kg Zn ha/sup -1/). The results obtained from these field trails showed that the combined application of FYM with NPK Zn increased the grain yield significantly over the other two treatments with an increase of 50-80% over the farmer's practice and 11 to 23 % over the recommended dose. As regards straw yields, T/sub 2/ and T/sub 3/ increased the yields significantly over farmer's practice (T) at all the sites; However, T/sub 2/ and T/sub 3/ at Thana and Kabal were at par with each other. As regards effect of various treatments on soil properties, organic matter content was improved at Thana and Kabal sites while at Matta the results were inconsistent. Similarly soil P and Zn contents were increased considerably in T/sub 2/ and T/sub 3/ at Thana and Kabal being at par with each other. It is apparent from these results that the crop productivity of eroded lands at all the three sties was considerably restored and the soil fertility status was improved by integrated plant nutrient management. (author)

  19. Laboratory bioassays to estimate the lethal and sublethal effects of various insecticides and fungicides on Deraeocoris brevis (Hemiptera: Miridae).

    Science.gov (United States)

    Amarasekare, K G; Shearer, P W

    2013-04-01

    This laboratory bioassay focused on lethal and sublethal effects of five insecticides (chlorantraniliprole, cyantraniliprole, spinetoram, novaluron, and lambda-cyhalothrin) and two fungicide treatments (sulfur and a mixture of copper hydroxide and mancozeb) on the predatory mired bug, Deraeocoris brevis (Uhler) (Hemiptera: Miridae) using second instars and adult males and females. Formulated pesticides were tested using concentrations that were equivalent to the high label rate (1x) (high rate) and 1/10th of that amount (0.1x) (low rate) dissolved in 378.5 liters of water. Lambda-cyhalothrin was highly toxic to D. brevis nymphs and adults at both rates, whereas both rates of novaluron were highly toxic to nymphs. Cyantraniliprole, chlorantraniliprole, and novaluron were less toxic to adults, and chlorantraniliprole and spinetoram were less toxic to nymphs. Both rates of spinetoram caused significant mortality to adults. Fecundity of adult females was affected negatively by the high rates of either novaluron or spinetoram, whereas the fertility was affected only by the high rate of novaluron. The high rate of spinetoram reduced survival of nymphs. Adults treated with spinetoram had reduced longevity. Cyantraniliprole caused some mortality to nymphs and affected their survival. Both rates of sulfur were toxic to nymphs and affected emergence to adults. The mixture of copper hydroxide and mancozeb was less toxic to D. brevis. Neither adult longevity nor sex ratio was affected by the fungicides. The r values for D. brecis treated with lambda-cyhalothrin, novaluron, spinetoram, and sulfur were low, indicating that these products may have negative impact on population growth.

  20. The fate of eroded soil organic carbon along a European transect – controls after deposition in terrestrial and aquatic systems

    DEFF Research Database (Denmark)

    Kirkels, Frédérique; Cammeraat, Erik; Kalbitz, Karsten

    that the turnover of deposited C is significantly affected by soil and organic matter properties, and whether deposition occurs in terrestrial or aquatic environments. We sampled topsoils from 10 agricultural sites along a European transect, spanning a wide range of SOC and soil characteristics (e.g. texture......The potential fate of eroded soil organic carbon (SOC) after deposition is key to understand carbon cycling in eroding landscapes. Globally, large quantities of sediments and SOC are redistributed by soil erosion on agricul-tural land, particularly after heavy precipitation events. Deposition......, aggregation, C content, etc.). Turnover of SOC was determined for terrestrial and aquatic depositional conditions in a 10-week incubation study. Moreover, we studied the impact of labile carbon inputs (‘priming’) on SOC stability using 13C labelled cellulose. We evaluated potentially important controls...

  1. Exposure to a widespread non-pathogenic bacterium magnifies sublethal pesticide effects in the damselfly Enallagma cyathigerum: From the suborganismal level to fitness-related traits

    International Nuclear Information System (INIS)

    Janssens, Lizanne; Stoks, Robby

    2013-01-01

    While there is increasing concern that pesticide stress can interact with stress imposed by antagonistic species including pathogens, it is unknown whether this also holds for non-pathogenic bacteria. We exposed Enallagma cyathigerum damselfly larvae to the pesticide chlorpyrifos and a non-pathogenic Escherichia coli strain. Both exposure to chlorpyrifos and E. coli reduced growth rate and fat storage, probably due to the observed energetically costly increases in physiological defence (glutathione-S-transferase and Hsp70) and, for E. coli, immune defence (phenoloxidase). Moreover, these stressors interacted for both fitness-related traits. Most importantly, another fitness-related trait, bacterial load, increased drastically with chlorpyrifos concentration. A possible explanation is that the upregulation of phenoloxidase in the presence of E. coli changed into a downregulation when combined with chlorpyrifos. We argue that the observed interactive, partly synergistic effects between pesticides and widespread non-pathogenic bacteria may be common and deserves further attention to improve ecological risk assessment of pesticides. -- Highlights: ► Non-pathogens such as the bacterium E. coli are ignored in ecotoxicology. ► Both E. coli and chlorpyrifos impaired fitness-related traits in damselfly larvae. ► E. coli modulated and magnified effects of chlorpyrifos on physiology and fitness. ► Bacterial load was magnified >10× in the presence of chlorpyrifos. ► Risk assessment of pesticides should consider synergisms with non-pathogens. -- Non-pathogenic bacteria reduce fitness-related traits and can synergistically interact with sublethal pesticide effects for physiological and fitness-related traits

  2. Effects of sublethal doses of thiacloprid and its formulation Calypso® on the learning and memory performance of honey bees.

    Science.gov (United States)

    Tison, Léa; Holtz, Sophie; Adeoye, Amy; Kalkan, Önder; Irmisch, Nina S; Lehmann, Nadja; Menzel, Randolf

    2017-10-15

    Learning and memory play a central role in the behavior and communication of foraging bees. We have previously shown that chronic uptake of the neonicotinoid thiacloprid affects the behavior of honey bees in the field. Foraging behavior, homing success, navigation performance and social communication were impaired. Thiacloprid collected at a feeding site at low doses accumulates in foragers over time. Here, we applied a laboratory standard procedure (the proboscis-extension response conditioning) in order to assess which processes, acquisition, memory consolidation and/or memory retrieval were compromised after bees were fed either with thiacloprid or the formulation of thiacloprid named Calypso ® at different sublethal doses. Extinction and generalization tests allowed us to investigate whether bees respond to a learned stimulus, and how selectively. We showed that thiacloprid, as active substance and as formulation, poses a substantial risk to honey bees by disrupting learning and memory functions. These data support and specify the data collected in the field. © 2017. Published by The Company of Biologists Ltd.

  3. The impacts of grazing land management on the wind erodibility of the Mulga Lands of western Queensland, Australia

    Science.gov (United States)

    An estimated 100 Mt of dust is eroded by wind from the Australian land surface each year. Wind erosion may be widespread across the arid and semi-arid rangelands, with impacts on soil nutrients, carbon and ecosystem services, human health, and climate. The susceptibility of landscapes to wind erosio...

  4. Metabolic responses of Eisenia fetida after sub-lethal exposure to organic contaminants with different toxic modes of action

    International Nuclear Information System (INIS)

    McKelvie, Jennifer R.; Wolfe, David M.; Celejewski, Magda A.; Alaee, Mehran; Simpson, Andre J.; Simpson, Myrna J.

    2011-01-01

    Nuclear magnetic resonance (NMR) - based metabolomics has the potential to identify toxic responses of contaminants within a mixture in contaminated soil. This study evaluated the metabolic response of Eisenia fetida after exposure to an array of organic compounds to determine whether contaminant-specific responses could be identified. The compounds investigated in contact tests included: two pesticides (carbaryl and chlorpyrifos), three pharmaceuticals (carbamazephine, estrone and caffeine), two persistent organohalogens (Aroclor 1254 and PBDE 209) and two industrial compounds (nonylphenol and dimethyl phthalate). Control and contaminant-exposed metabolic profiles were distinguished using principal component analysis and potential contaminant-specific biomarkers of exposure were found for several contaminants. These results suggest that NMR-based metabolomics offers considerable promise for differentiating between the different toxic modes of action (MOA) associated with sub-lethal toxicity to earthworms. - Highlights: → NMR-based earthworm metabolomic analysis of the toxic mode of action of various environmental contaminants. → Organic chemicals with different toxic modes of action resulted in varied metabolomic responses for E. fetida. → NMR-based metabolomics differentiates between the different modes of action associated with sub-lethal toxicity. - 1 H NMR metabolomics was used to identify potential biomarkers of organic contaminant exposure in Eisenia fetida earthworms.

  5. Correlation of erosion and erodibility assessments using caesium-137

    International Nuclear Information System (INIS)

    Elliott, G.L.; Campbell, B.L.; Loughran, R.J.

    1984-01-01

    Data are presented which show that in soils in which net erosion is occurring, the content of the environmental isotope caesium-137 is highly correlated with soil loss. Other soil characteristics which may be related to the caesium content and therefore to soil loss have also been examined. Of these factors, an improved index of soil aggregate stability explained the most variation in caesium content (52%). Soil organic matter content explained 27% of variation in caesium content and other soil erodibility indices based on quantitative measurement of aggregate stability, explained between 6% and 21% of the variation. Indices based on implied hydrologic characteristics, implied aggregation and clay dispersion explained between 1% and 3% of caesium variation. It is suggested that practical factors of soil protection are relevant to the prediction of erosion hazard and may be more relevant than some indices of soil resistance. It is noted further that caesium-137 content of a soil gives every indication of being a most suitable predictor of soil erosion status

  6. Evaluating the stress response as a bioindicator of sub-lethal effects of crude oil exposure in wild house sparrows (Passer domesticus.

    Directory of Open Access Journals (Sweden)

    Christine R Lattin

    Full Text Available Petroleum can disrupt endocrine function in humans and wildlife, and interacts in particularly complex ways with the hypothalamus-pituitary-adrenal (HPA axis, responsible for the release of the stress hormones corticosterone and cortisol (hereafter CORT. Ingested petroleum can act in an additive fashion with other stressors to cause increased mortality, but it is not clear exactly why--does petroleum disrupt feedback mechanisms, stress hormone production, or both? This laboratory study aimed to quantify the effects of ingested Gulf of Mexico crude oil on the physiological stress response of house sparrows (Passer domesticus. We examined baseline and stress-induced CORT, negative feedback, and adrenal sensitivity in house sparrows given a 1% oil or control diet (n = 12 in each group. We found that four weeks on a 1% oil diet did not alter baseline CORT titers or efficacy of negative feedback, but significantly reduced sparrows' ability to secrete CORT in response to a standardized stressor and adrenocorticotropin hormone injection, suggesting that oil damages the steroid-synthesizing cells of the adrenal. In another group of animals on the same 1% oil (n = 9 or control diets (n = 8, we examined concentrations of eight different blood chemistry parameters, and CORT in feathers grown before and during the feeding experiments as other potential biomarkers of oil exposure. None of the blood chemistry parameters differed between birds on the oil and control diets after two or four weeks of feeding, nor did feather CORT differ between the two groups. Overall, this study suggests that the response of CORT to stressors, but not baseline HPA function, may be a particularly sensitive bioindicator of sub-lethal chronic effects of crude oil exposure.

  7. Evaluating the stress response as a bioindicator of sub-lethal effects of crude oil exposure in wild house sparrows (Passer domesticus).

    Science.gov (United States)

    Lattin, Christine R; Ngai, Heather M; Romero, L Michael

    2014-01-01

    Petroleum can disrupt endocrine function in humans and wildlife, and interacts in particularly complex ways with the hypothalamus-pituitary-adrenal (HPA) axis, responsible for the release of the stress hormones corticosterone and cortisol (hereafter CORT). Ingested petroleum can act in an additive fashion with other stressors to cause increased mortality, but it is not clear exactly why--does petroleum disrupt feedback mechanisms, stress hormone production, or both? This laboratory study aimed to quantify the effects of ingested Gulf of Mexico crude oil on the physiological stress response of house sparrows (Passer domesticus). We examined baseline and stress-induced CORT, negative feedback, and adrenal sensitivity in house sparrows given a 1% oil or control diet (n = 12 in each group). We found that four weeks on a 1% oil diet did not alter baseline CORT titers or efficacy of negative feedback, but significantly reduced sparrows' ability to secrete CORT in response to a standardized stressor and adrenocorticotropin hormone injection, suggesting that oil damages the steroid-synthesizing cells of the adrenal. In another group of animals on the same 1% oil (n = 9) or control diets (n = 8), we examined concentrations of eight different blood chemistry parameters, and CORT in feathers grown before and during the feeding experiments as other potential biomarkers of oil exposure. None of the blood chemistry parameters differed between birds on the oil and control diets after two or four weeks of feeding, nor did feather CORT differ between the two groups. Overall, this study suggests that the response of CORT to stressors, but not baseline HPA function, may be a particularly sensitive bioindicator of sub-lethal chronic effects of crude oil exposure.

  8. Soil aggregates, organic matter turnover and carbon balance in a Mediterranean eroded vineyard

    Science.gov (United States)

    Novara, Agata; Lo Papa, Giuseppe; Dazzi, Carmelo; Gristina, Luciano; Cerdà, Artemi

    2014-05-01

    The carbon cycle is being affected by the human impacts (Novara et al., 2011; Yan-Gui et al., 2013), and one of those is the intensification in the soil erosion in agriculture land (Cerdà et al., 2009; García Orenes et al., 2009). Vineyards also are affected by the human activities (Fernández Calviño, 2012). Vineyards in Sicily are cultivated on 110.000 ha, 10% of which on >10% slope. Deficiencies of soil organic matter are typical of the semi arid Mediterranean environment especially where traditional intensive cropping practices are adopted (Novara et al., 2012; 2013). These practices in vineyards could lead soil to intensive erosion processes (Novara et al., 2011). The fate of SOC under erosion processes is difficult to understand because of the influence of the erosion impact on SOC pathway, which depends on the different features of the process involved (detachment, transport and/or deposition). Soil erosion must be considered a net C source (Lal, 2003), as eroded soils have lower net primary productivity (NPP) (Dick and Gregorich, 2004) caused by reduction in the effective rooting depth and all in all determining decline in soil quality. Breakdown of aggregates and soil dispersion expose SOM to microbial/enzymatic processes and chemical soil properties (Dimoyiannis, 2012; Kocyigit and Demirci, 2012). Moreover the light fraction, transported by runoff, is labile and easily mineralized determining CO2 emission in the atmosphere (Jacinthe and Lal, 2004). Therefore, the carbon pool is lower in eroded than in un-eroded soil scapes and the rate of mineralization of soil organic matter is higher in sediments than in original soil. In this survey we show a research conducted on a slope sequence of three soil profiles in an irrigated vineyard located in Sambuca di Sicilia, Italy (UTM33-WGS84: 4169367N; 325011E). The SOC content was measured at depth intervals of 10 cm up to a depth of 60 cm in each pedon. Wet aggregate-size fractions with no prior chemical

  9. A proteomic evaluation of the effects of the pharmaceuticals diclofenac and gemfibrozil on marine mussels (Mytilus spp.): evidence for chronic sublethal effects on stress-response proteins.

    Science.gov (United States)

    Schmidt, Wiebke; Rainville, Louis-Charles; McEneff, Gillian; Sheehan, David; Quinn, Brian

    2014-03-01

    Human pharmaceuticals (e.g. the lipid regulator gemfibrozil and the non-steroidal anti-inflammatory drug diclofenac) are an emerging environmental threat in the aquatic environment. This study aimed to evaluate sublethal effects of these two commonly found pharmaceuticals on the protein profiles of marine mussels (Mytilus spp.). Mytilus spp. was exposed to environmentally relevant and elevated concentrations (1 and 1000 µg/l respectively) of both drugs for 14 days. In addition, mussels were maintained for seven days post treatment to examine the potential of blue mussels to recover from such an exposure. Differential protein expression signatures (PES) in the digestive gland of mussels were obtained using two-dimensional gel electrophoresis after 7, 14, and 21 days of exposure. Twelve spots were significantly increased or decreased by gemfibrozil and/or diclofenac, seven of which were successfully identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. These proteins were involved in energy metabolism, oxidative stress response, protein folding, and immune responses. Changes in the PES over time suggested that mussels were still experiencing oxidative stress for up to seven days post exposure. In addition, a suite of biomarkers comprising glutathione transferase, lipid peroxidation, and DNA damage were studied. An oxidative stress response was confirmed by biomarker responses. To our knowledge, this is the first investigation using proteomics to assess the potential effects of human pharmaceuticals on a non-target species in an environmentally-relevant model. The successful application of this proteomic approach supports its potential use in pollution biomonitoring and highlights its ability to aid in the discovery of new biomarkers. Copyright © 2013 John Wiley & Sons, Ltd.

  10. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: Soil Erodibility (KFFACT)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the adjusted soil erodibility factor within individual, local NHDPlusV2 catchments and upstream, contributing watersheds. Attributes of the...

  11. The radiobiology of laser-driven particle beams: focus on sub-lethal responses of normal human cells

    International Nuclear Information System (INIS)

    Manti, L.; Perozziello, F.M.; Romagnani, L.; Borghesi, M.; Doria, D.; Candiano, G.; Cirrone, G.A.P.; Leanza, R.; Romano, F.; Scuderi, V.; Tramontana, A.; Chaudhary, P.; Gwynne, D.; Prise, K. M.

    2017-01-01

    Accelerated proton beams have become increasingly common for treating cancer. The need for cost and size reduction of particle accelerating machines has led to the pioneering investigation of optical ion acceleration techniques based on laser-plasma interactions as a possible alternative. Laser-matter interaction can produce extremely pulsed particle bursts of ultra-high dose rates (≥ 10 9 Gy/s), largely exceeding those currently used in conventional proton therapy. Since biological effects of ionizing radiation are strongly affected by the spatio-temporal distribution of DNA-damaging events, the unprecedented physical features of such beams may modify cellular and tissue radiosensitivity to unexplored extents. Hence, clinical applications of laser-generated particles need thorough assessment of their radiobiological effectiveness. To date, the majority of studies have either used rodent cell lines or have focussed on cancer cell killing being local tumour control the main objective of radiotherapy. Conversely, very little data exist on sub-lethal cellular effects, of relevance to normal tissue integrity and secondary cancers, such as premature cellular senescence. Here, we discuss ultra-high dose rate radiobiology and present preliminary data obtained in normal human cells following irradiation by laser-accelerated protons at the LULI PICO2000 facility at Laser Lab Europe, France.

  12. Stress response of the black coral Leiopathes glaberrima when exposed to sub-lethal amounts of crude oil and dispersant

    Directory of Open Access Journals (Sweden)

    Dannise V. Ruiz-Ramos

    2017-12-01

    Full Text Available The 2010 Deep Water Horizon oil well failure released billions of gallons of crude oil into the deep Gulf of Mexico, and, combined with chemical dispersants, this oil caused significant coral mortality. However, the mechanisms by which oil and dispersed oil impact deep marine fauna are not well understood. Here, we investigate the effects of oil and dispersed oil on a black coral common in the deep Gulf of Mexico, 'Leiopathes glaberrima. 'This coral occurs in several color morphs that show ecological and genetic differences. We hypothesized that dispersed oil would be more detrimental to coral health than oil alone and that this difference would be detectable in the gene expression response of the colonies even at sub-lethal concentrations. In two experiments, four and six colonies of red and white color morphs were exposed to oil, dispersant, and dispersed oil for a minimum of 96 hours. Visual assessment indicated that indeed dispersant and dispersed oil treatments were more damaging than oil alone, for target concentrations of 25 mg L–1. Decline in health was observed for all treatments, independently of color morphotype, but the decline was faster in the white colonies exposed to dispersant. The responses to the treatments were also investigated by monitoring gene expression after 24 hours of sub-lethal chemical exposure. Coral gene expression differed by chemical stressor. Interestingly, the polycyclic aromatic hydrocarbon biomarker gene, cytochrome P450, was only up-regulated in dispersed oil but not oil alone, suggesting that the dispersant increased the availability of such hydrocarbons in the tissue. The gene expression response was apparent at 24 hours when visual impacts were not (yet detectable. The use of chemical dispersants in oil-spill remediation may cause health declines in deep-water corals and deserves further study.

  13. Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells.

    Science.gov (United States)

    Pavlikova, Nela; Smetana, Pavel; Halada, Petr; Kovar, Jan

    2015-10-01

    Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Effect of farmyard manure, mineral fertilizers and mung bean residues on some microbiological properties of eroded soil in district Swat

    Directory of Open Access Journals (Sweden)

    M. Naeem

    2009-05-01

    Full Text Available The present study was conducted to evaluate the efficacy of organic and inorganic fertilizers and mung bean residues on improving microbiological properties of eroded lands of District Swat, North West Frontier Province (NWFP Pakistan under wheat-mung bean-wheat cropping system during 2006 to 2008. The experiment was laid out in RCBD split-plot arrangement. Mung bean was grown and a basal dose of 25-60 kg N-P2O5 ha-1 was applied. After mung bean harvest, three residues management practices, i.e., R+ (mung bean residues incorporated into soil, R- (mung bean residues removed and F (fallow were performed in the main-plots. Sub-plot factor consisted of six fertilizer treatments for wheat crop i.e., T1 (control, T2 (120 kg N ha-1, T3 (120-90-0 kg N-P2O5-K2O ha-1, T4 (120-90-60 kg N-P2O5-K2O ha-1, T5 (90-90-60 kg N-P2O5-K2O + 10 t FYM ha-1 and T6 (60-90-60 kg N-P2O5- K2O + 20 t FYM ha-1. The results showed that microbial activity, microbial biomass-C and-N, mineralizable C and N were highest with T6 as well as with the incorporation of mung bean residues (R+. Compared with control, T6 increased microbial biomass C, N, mineralizable C and N by 33.8, 164.1, 35.5 and 110.6% at surface and 38.4, 237.5, 38.7 and 124.1% at sub-surface soil, respectively, while R+ compared with fallow increased these properties by 33.7, 47.4, 21.4 and 32.2% at surface and 36.8, 51, 21.9 and 35.4% at sub-surface soil, respectively. Inclusion of mung bean with its residues incorporated and application of 20 t FYM ha-1 and reducing inorganic N fertilizer to 60 kg N ha-1 for wheat is recommended for improving microbiological properties of slightly eroded lands

  15. Alteration of cytochrome P450 1 regulation and HSP 70 level in brain of juvenile common carp (Cyprinus carpio) after chronic exposure to tributyltin.

    Science.gov (United States)

    Li, Zhi-Hua; Zhong, Li-Qiao; Wu, Yan-Hua; Mu, Wei-Na

    2016-02-01

    Tributyltin (TBT), a toxic contaminant in aquatic environments, has bio-accumulated in aquatic food webs throughout the world and can be found at toxic levels in some biota. However, the molecular mechanisms and effects of TBT are not fully understood. The aim of the present study was to investigate the effect of long-term exposure of TBT on cytochrome P450 (CYP450) 1 regulation and heat-shock proteins (HSPs) profiling in brain of freshwater teleost. The effects of long-term exposure to TBT on mRNA expression of cytochrome P450 (CYP450) 1 family genes and ethoxyresorufin O-deethylase (EROD) activity in the brain of common carp were evaluated, as well as HSP 70 level. Fish were exposed to sublethal concentrations of TBT (75 ng/L, 0.75 μg/L and 7.5 μg/L) for 15, 30, and 60 days. Based on the results, long-term exposure (more than 15 days) to TBT could lead to obvious physiological-biochemical responses (based on EROD activity, HSP 70 level and CYP450 1 family genes expression). The mRNA expression of CYP450 1 family genes (CYP1A, CYP1B, CYP1C1 and CYP1C2) suggested that CYP1A was to accommodate most EROD activity in fish, but other CYP450 forms also involved in this proceeding. Thus, the measured physiological responses in fish brain could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity and could be used as potential biomarkers for monitoring the TBT pollution in the field.

  16. Surgical excision of eroded mesh after prior abdominal sacrocolpopexy.

    Science.gov (United States)

    South, Mary M T; Foster, Raymond T; Webster, George D; Weidner, Alison C; Amundsen, Cindy L

    2007-12-01

    months. Seven patients ultimately required abdominal excision and all had symptom resolution, however, not without complications. Two patients had bowel injury during lysis of adhesions requiring bowel resection in 1 case and repair in another, 1 had a postoperative wound infection with breakdown, 1 was readmitted for postoperative fever requiring antibiotics, and 1 had an acute coronary syndrome requiring transfer to the cardiology service. Transvaginal excision of mesh with or without endoscopy appears to be a safe and less invasive method for excision of eroded vaginal mesh after prior abdominal sacrocolpopexy. Up to 3 vaginal excision attempts may be necessary to achieve symptom resolution, and complete removal of mesh will likely improve outcomes with the transvaginal technique. Although abdominal excision can be considered the gold standard for excision of eroded mesh, it is not without potentially increased morbidity.

  17. Long-term evaluation of lethal and sublethal toxicity of industrial effluents using Daphnia magna and Moina macrocopa.

    Science.gov (United States)

    Yi, Xianliang; Kang, Sung-Wook; Jung, Jinho

    2010-06-15

    Acute toxicity and feeding rate inhibition of effluent from a wastewater treatment plant and its adjacent stream water on Daphnia magna and Moina macrocopa were comparatively studied. The acute toxicity of the final effluent (FE) fluctuated greatly over the sampling period from January to August 2009. Toxicity identification results of the FE in July 2009 showed that Cu originating from the Fenton's reagent was likely a key toxicant. In addition, the feeding rate of both species was still inhibited by the FEs in which acute toxicity was not observed. These findings indicate that the feeding response would be a useful tool for monitoring sublethal effects of industrial effluents. For the acute toxicity test, M. macrocopa was more sensitive than D. magna, but the opposite result was true in the case of the feeding rate inhibition. These suggest that different species have different sensitivities to toxic chemicals and to the test methods. Copyright 2010 Elsevier B.V. All rights reserved.

  18. Coupled diffusion of two species in a slab with an eroding boundary

    International Nuclear Information System (INIS)

    Leite, S.B.; Ozisik, M.N.; Verghese, K.

    1981-01-01

    The diffusion of two interchangeable species in a medium with an eroding boundary is analyzed by modeling the problem as the solution of two diffusion equations coupled at the source term for a slab with a moving boundary. Formal solutions are developed for the concentration of the two species as a function of time and position in the slab for arbitrary initial distributions of the diffusing species, arbitrary sources within the medium and boundary conditions of the third kind at the bounding surfaces. It is shown with an illustrative example, that the resulting coupled integral equations for the species can be solved very efficiently by an approach employing both a lower- and upper-bound starting function for the concentrations. (author)

  19. Effects of herbicides on fish

    DEFF Research Database (Denmark)

    Solomon, Keith R.; Dalhoff, Kristoffer; Volz, David

    2013-01-01

    Herbicides are used to control weeds and are usually targeted to processes and target sites that are specific to plants. As a result, most herbicides are not acutely toxic to fish. Exceptions to this general rule are uncouplers of oxidative phosphorylation and some herbicides that interfere...... with cell division. Chronic and sublethal effects have been studied for some herbicides, but fewer data are available for these effects than for acute effects. The sublethal effects of herbicides that have been studied include reproduction, stress, olfaction, and behavior. Although some of these responses......, and reproduction. As with all pesticides, herbicides may have indirect effects in fish. These effects are mediated by herbicide-induced changes in food webs or in the physical environment. Indirect effects can only occur if direct effects occur first and would be mediated by the killing of plants by herbicides...

  20. 1H NMR-Based Metabolomic Analysis of Sub-Lethal Perfluorooctane Sulfonate Exposure to the Earthworm, Eisenia fetida, in Soil

    Directory of Open Access Journals (Sweden)

    Myrna J. Simpson

    2013-08-01

    Full Text Available 1H NMR-based metabolomics was used to measure the response of Eisenia fetida earthworms after exposure to sub-lethal concentrations of perfluorooctane sulfonate (PFOS in soil. Earthworms were exposed to a range of PFOS concentrations (five, 10, 25, 50, 100 or 150 mg/kg for two, seven and fourteen days. Earthworm tissues were extracted and analyzed by 1H NMR. Multivariate statistical analysis of the metabolic response of E. fetida to PFOS exposure identified time-dependent responses that were comprised of two separate modes of action: a non-polar narcosis type mechanism after two days of exposure and increased fatty acid oxidation after seven and fourteen days of exposure. Univariate statistical analysis revealed that 2-hexyl-5-ethyl-3-furansulfonate (HEFS, betaine, leucine, arginine, glutamate, maltose and ATP are potential indicators of PFOS exposure, as the concentrations of these metabolites fluctuated significantly. Overall, NMR-based metabolomic analysis suggests elevated fatty acid oxidation, disruption in energy metabolism and biological membrane structure and a possible interruption of ATP synthesis. These conclusions obtained from analysis of the metabolic profile in response to sub-lethal PFOS exposure indicates that NMR-based metabolomics is an excellent discovery tool when the mode of action (MOA of contaminants is not clearly defined.

  1. Sublethal toxicity and biotransformation of pyrene in Lumbriculus variegatus (Oligochaeta)

    International Nuclear Information System (INIS)

    Maeenpaeae, K.; Leppaenen, M.T.; Kukkonen, J.V.K.

    2009-01-01

    The aim of this work was to study the toxicity and biotransformation of polyaromatic hydrocarbon (PAH) pyrene in the oligochaete aquatic worm, Lumbriculus variegatus. PAHs are ubiquitous environmental pollutants that pose a hazard to aquatic organisms, and metabolizing capability is poorly known in the case of many invertebrate species. To study the toxicity and biotransformation of pyrene, the worm was exposed for 15 days to various concentrations of water-borne pyrene. The dorsal blood vessel pulse rate was used as a sublethal endpoint. Pyrene biotransformation by L. variegatus was studied and the critical body residues (CBR) were estimated for pyrene toxicity. The toxicokinetics of pyrene uptake was evaluated. A combination of radiolabeled ( 14 C) and nonlabeled pyrene was used in the exposures, and liquid scintillation counting (LSC) and high-pressure liquid chromatography were employed in both water and tissue residue analyses. The results showed that L. variegatus was moderately able to metabolize pyrene to 1-hydroxypyrene (1-HP), thus demonstrating that the phase-I-like oxidizing enzyme system metabolizes pyrene in L. variegatus. The amount of the 1-HP was 1-2% of the amount of pyrene in the worm tissues. The exposure to pyrene reduced the blood vessel pulse rate significantly (p < 0.05), showing that pyrene had a narcotic effect. The estimated CBRs remained constant during the exposure time, varying from 0.120 to 0.174 mmol pyrene/kg worm wet weight. The bioconcentration factors (BCF) decreased as exposure concentration increased. It was suggested that the increased toxicity of pyrene accounted for the decrease in BCFs by lowering the activity of the organism

  2. DNA polymerase inhibitors and heat alter fixation of postirradiation sublethal damage in L5178Y-S cells

    International Nuclear Information System (INIS)

    Kapiszewska, M.; Szumiel, I.; Lange, C.S.

    1988-01-01

    We have used the inhibitor of DNA polymerase alpha, aphidicolin (apc) (0.5 μg/ml for 1 h), or that of DNA polymerase beta, dideoxythymidine triphosphate (ddTTP) (5 μg/ml), as well as heat (15 min at 43 deg C) to examine fixation of sublethal damage (SLD) induced by X-rays in L5178Y-S (LY-S) cells. This cell line has the unique property of responding to split X-ray doses at 37 deg C by decreased survival. This effect was partly abolished by heating the cells before irradiation with the second dose; the protection was most pronounced when the cells were heated 30-120 min. after the first dose of radiation. Since similar changes in postirradiation survival occurred when ddTTP was applied, we suggest that heat induces a loss of polymerase beta activity. Apc gave a smaller protective effect. We interpreted these results as suggesting that mismatching takes place during DNA semiconservative replication or repair; inhibition of replication results in survival increase, by preventing misrepair. A proper timing of treatment with the inhibitors or heat is essential to obtain the sparing effect, i.e. to prevent SLD fixation. 27 refs., 3 figs., 1 tab. (author)

  3. Intramuscular Cobinamide Sulfite in a Rabbit Model of Sub-Lethal Cyanide Toxicity

    Science.gov (United States)

    Brenner, Matthew; Kim, Jae G.; Mahon, Sari B.; Lee, Jangwoen; Kreuter, Kelly A.; Blackledge, William; Mukai, David; Patterson, Steve; Mohammad, Othman; Sharma, Vijay S.; Boss, Gerry R.

    2009-01-01

    Objective To determine the ability of an intramuscular cobinamide sulfite injection to rapidly reverse the physiologic effects of cyanide toxicity. Background Exposure to cyanide in fires and industrial exposures and intentional cyanide poisoning by terrorists leading to mass casualties is an ongoing threat. Current treatments for cyanide poisoning must be administered intravenously, and no rapid treatment methods are available for mass casualty cyanide exposures. Cobinamide is a cobalamin (vitamin B12) analog with an extraordinarily high affinity for cyanide that is more water-soluble than cobalamin. We investigated the use of intramuscular cobinamide sulfite to reverse cyanide toxicity induced physiologic changes in a sublethal cyanide exposure animal model. Methods New Zealand white rabbits were given 10 mg sodium cyanide intravenously over 60 minutes. Quantitative diffuse optical spectroscopy and continuous wave near infrared spectroscopy monitoring of tissue oxy- and deoxyhemoglobin concentrations were performed concurrently with blood cyanide level measurements and cobinamide levels. Immediately after completion of the cyanide infusion, the rabbits were injected intramuscularly with cobinamide sulfite (n=6) or inactive vehicle (controls, n=5). Results Intramuscular administration led to rapid mobilization of cobinamide and was extremely effective at reversing the physiologic effects of cyanide on oxyhemoglobin and deoxyhemoglobin extraction. Recovery time to 63% of their baseline values in the central nervous system was in a mean of 1032 minutes in the control group and 9 minutes in the cobinamide group with a difference of 1023 minutes (95% confidence interval [CI] 116, 1874 minutes). In muscle tissue, recovery times were 76 and 24 minutes with a difference of 52 minutes (95% CI 7, 98min). Red blood cell cyanide levels returned towards normal significantly faster in cobinamide sulfite-treated animals than in control animals. Conclusions Intramuscular

  4. PAH-induced sublethal narcosis alters the bioenergetics and bioaccumulation of Fundulus heteroclitus

    Energy Technology Data Exchange (ETDEWEB)

    Merten, A. [NOAA Office of Response and Restoration, Hazardous Materials and Response, Seattle (United States); Beard, E.; Baker, B. [Univ. of Maryland, Solomons (United States)

    2004-09-15

    Accumulation of non-polar narcotic chemicals in organisms alters their metabolic rates and, therefore their energetic demands. Since exposure of these hydrophobic chemicals is primarily through the diet, we hypothesize that decreasing metabolic rates caused by accumulation of narcotics reduces feeding which, in turn, decreases further exposure to the narcotic. Thus, dietary exposure to and accumulation of narcotics may cause a negative feedback, reducing net bioaccumulation. The purpose of this short paper is to discuss the results of a long-term fish contaminant exposure study and to describe a fish bioenergetics model coupled to a PCBbioaccumulation model. The laboratory component consisted of exposing the estuarine fish Fundulus heteroclitus to environmentally-relevant levels of hydrophobic organic contaminants (HOCs) through their diet. We developed the model to further examine and understand the consequences of sublethal narcosis at both the individual and population levels of Fundulus heteroclitus.

  5. Effect of Biochar Application on Erodibility of Plow Layer Soil on Loess Slopes%添加生物炭对黄绵土耕层土壤可蚀性的影响

    Institute of Scientific and Technical Information of China (English)

    吴媛媛; 杨明义; 张风宝; 张加琼; 赵恬茵; 刘淼

    2016-01-01

    The Loess Plateau is one of the areas that suffer the most serious soil erosion and the soil in the area is characterized by low soil fertility and high soil erodibility. Thanks to its inherent characteristics and physicochemical properties,biochar has become a novel soil structure amendment. However,so far studies on biochar have mostly focused on its effects of improving soil physical and chemical properties and plant growth conditions,reducing greenhouse gas emission and remedying polluted soil,and demonstrated that its positive effects on soil quality,soil bulk density,soil porosity,quantity and structure of soil aggregate and soil water dynamics. Little has been reported on its effects on soil resistance to erosion. Getting to know the effects of biochar on soil erosion will be of great significance not only to soil and water conservancy,but also to soil building and crop yield. An indoor artificial rainfall experiment was carried out to explore effect of biochar on sheet erosion on loessal soil slope. The experiment was designed to have one rainfall intensity(90 mm h-1),five application rates(0%,1%,3%,5% and 7%)and three particle sizes(<2mm,<1mm and<0.25mm)of biochar of sawdust. Results show that the effect of biochar application on erodibility of loessal soil plow layers is attributed mainly to its effects altering composition and porosity of the soil and the effect of its own properties on water,which were embodied in delayed runoff and reduced runoff and sediment yields and sediment in runoff. Incorporation of biochar,the same in particle size,shortened the duration of runoff and the effect intensified with rising application rate of biochar. However,when the application rate was lower than 3%,it delayed runoff,but when the rate went on rising,it affected runoff reversely. Incorporations of biochar,the same in rate,but different in particle size,did not show much difference in affecting time of runoff yield. Incorporation of biochar of any size at a rate

  6. Repeated sublethal exposures to the sea lice pesticide Salmosan® (azamethiphos) on adult male lobsters (Homarus americanus) causes neuromuscular dysfunction, hypoxia, metabolic disturbances and mortality.

    Science.gov (United States)

    Dounia, Daoud; Andrea, Battison; Lefort, Natalie; Van Geest, Jordana Lynne

    2016-12-01

    In Atlantic Canada and other salmon-growing regions, treatment of sea lice infestations in salmon aquaculture is necessary to protect fish health. The product Salmosan®, which contains the organophosphate azamethiphos as the active ingredient, is a pesticide presently used for treatment against sea lice. It is applied as a bath treatment and then released into the surrounding seawater. The potential for lethality to non-target species following acute and chronic exposures to Salmosan® has been studied over the past decade, however, the potential for sublethal effects on lobsters remains a concern. Adult male lobsters were exposed to 0.06, 0.5, and 5µgL -1 azamethiphos for one hour, repeated five times, over 48h. Lobsters were assessed immediately after exposure and over six days of recovery. Inhibition of muscle cholinesterase activity was detected in lobsters exposed to 0.5 and 5µgL -1 azamethiphos. The 5µgL -1 dose was considered lethal (93% cumulative mortality). Significant changes in hemolymph plasma biochemistry were most apparent in the 5µgL -1 exposure group in the immediate post-exposure samples. Citrate synthase activity was significantly lower in muscles of the 0.5µgL -1 exposure group compared to control lobsters. Mean electron transport system and standard metabolic rates tended to be lower in muscle tissue of the 0.5µgL -1 exposure group than control group lobsters. These results suggest that sublethal effects on lobster energetics may occur under laboratory exposure conditions (i.e., concentrations and duration) considered environmentally relevant, which could result in impairment under natural conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Sensitivity Analysis of the USLE Soil Erodibility Factor to Its Determining Parameters

    Science.gov (United States)

    Mitova, Milena; Rousseva, Svetla

    2014-05-01

    Soil erosion is recognized as one of the most serious soil threats worldwide. Soil erosion prediction is the first step in soil conservation planning. The Universal Soil Loss Equation (USLE) is one of the most widely used models for soil erosion predictions. One of the five USLE predictors is the soil erodibility factor (K-factor), which evaluates the impact of soil characteristics on soil erosion rates. Soil erodibility nomograph defines K-factor depending on soil characteristics, such as: particle size distribution (fractions finer that 0.002 mm and from 0.1 to 0.002 mm), organic matter content, soil structure and soil profile water permeability. Identifying the soil characteristics, which mostly influence the K-factor would give an opportunity to control the soil loss through erosion by controlling the parameters, which reduce the K-factor value. The aim of the report is to present the results of analysis of the relative weight of these soil characteristics in the K-factor values. The relative impact of the soil characteristics on K-factor was studied through a series of statistical analyses of data from the geographic database for soil erosion risk assessments in Bulgaria. Degree of correlation between K-factor values and the parameters that determine it was studied by correlation analysis. The sensitivity of the K-factor was determined by studying the variance of each parameter within the range between minimum and maximum possible values considering average value of the other factors. Normalizing transformation of data sets was applied because of the different dimensions and the orders of variation of the values of the various parameters. The results show that the content of particles finer than 0.002 mm has the most significant relative impact on the soil erodibility, followed by the content of particles with size from 0.1 mm to 0.002 mm, the class of the water permeability of the soil profile, the content of organic matter and the aggregation class. The

  8. Effects of sublethal gamma radiation on T and B cell activity in the antibody response of mice

    International Nuclear Information System (INIS)

    Carlson, D.E.; Lubet, R.A.

    1976-01-01

    The relative radiosensitivity of T and B cells was followed in sublethally irradiated mice reconstituted with bone marrow cells, thymus cells, or both, and simultaneously challenged with sheep erythrocytes. Numbers of antibody-forming cells in recipient spleens were determined on days 4 to 8. In this assay the response of mice given bone marrow cells was limited by the amount of residual T cell activity, while the response of mice given thymus cells was limited by the residual B cell activity. Although residual activity of both T and B cells was suppressed in mice given 300 to 700 rad at 80 rad/min, residual B cell activity was consistently lower in these animals. When antibody responses were initiated at intervals after irradiation, B cell activity was clearly limiting by 48 hr after 500 or 600 rad. The activity of both T and B cells was sensitive to differences in dose rate between 8 and 80 rad/min. The 4 to 7 fold dose-rate sensitivity of T cells paralleled that of differentially irradiated nonreconstituted mice. In contrast, dose-rate dependence of B cell activity varied from 10- to 20-fold between 8 and 80 rad/min. These results suggest that radiation suppression of antibody responses in mice is highly dependent upon B cell sensitivity, and that dose-rate dependence of the antibody response may be explained in large part by differential sensitivity of B cells

  9. Accumulation and Sublethal Effects of Triclosan and its Transformation Product Methyl-triclosan in the Earthworm Eisenia andrei Exposed to Environmental Concentrations in an Artificial Soil.

    Science.gov (United States)

    Chevillot, Fanny; Guyot, Mélanie; Desrosiers, Mélanie; Cadoret, Nicole; Veilleux, Éloïse; Cabana, Hubert; Bellenger, Jean-Philippe

    2018-04-18

    Municipal biosolids are increasingly used as a low-cost fertilizer in agricultural soil. Biosolids are contaminated by low concentrations (ng g -1 dw range) of a large variety of organic contaminants, such as triclosan (TCS). The effect of exposure to low concentrations of organic contaminants on soil biota remains largely undocumented. We evaluated the sublethal effects of TCS on the earthworm Eisenia andrei using an artificial soil amended with a nominal concentration of TCS of 50 ng g -1 dry weight soil. Using a 56-d reproduction test, we monitored the effect of TCS exposure on adult earthworm survival, growth, and reproduction. The bioaccumulation of TCS in earthworm tissue (adults and juveniles) and degradation of TCS were monitored. The genotoxicity of TCS was evaluated using a comet assay (DNA damage) on adult earthworm coelomocytes. Exposure to a low concentration of TCS had no significant effects on adult earthworm survival and DNA damage, but significantly stimulated growth (P increase in the number of cocoons and juveniles, and a decrease in the mean dry weight of juveniles. The bioaccumulation of TCS in earthworms was moderate (bioaccumulation factor ∼ 2). In biosolid-borne trials, the bioaccumulation of methyl-triclosan in earthworm tissues was higher than the parent compound TCS. We conclude that exposure to low concentrations of TCS in artificial soil can significantly affect the growth and reproductive performance of earthworms (i.e., E. andrei). More research is required with natural soils to assess TCS bioavailability for earthworms. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  10. Lethal and sublethal measures of chronic copper toxicity in the eastern narrowmouth toad, Gastrophryne carolinensis.

    Science.gov (United States)

    Flynn, R Wesley; Scott, David E; Kuhne, Wendy; Soteropoulos, Diana; Lance, Stacey L

    2015-03-01

    Many metals are acutely toxic to aquatic organisms at high concentrations and for some metals, such as copper (Cu), even low-level chronic contamination may be cause for conservation concern. Amphibian susceptibility to Cu has been examined in only a few species, and susceptibility is highly variable. The lethal and sublethal effects were examined of chronic aqueous Cu exposure on embryonic and larval eastern narrowmouth toads, Gastrophryne carolinensis. Copper levels as low as 10 μg Cu/L reduced embryonic and larval survival. Embryonic survivorship varied within- and between-source populations, with embryos derived from uncontaminated-wetland parents having greater survival at lower Cu levels than embryos from parents from a metal-contaminated constructed wetland. At 30 μg/L, embryos from the contaminated site had greater survival. Overall survival from oviposition to metamorphosis was 68.9% at 0 μg/L and 5.4% at 10 μg/L. Similarly, embryos exposed to ≥50 μg/L demonstrated developmental delays in transition from embryo to free-swimming larva. These results demonstrate a negative population-specific response to environmentally relevant levels of Cu. © 2014 SETAC.

  11. Lethal and sublethal effects of pesticides on Chrysoperla carnea larvae (Neuroptera: Chrysopidae) and the influence of rainfastness in their degradation pattern over time.

    Science.gov (United States)

    Maia, Jader Braga; Carvalho, Geraldo Andrade; Medina, Pilar; Garzón, Agustín; Gontijo, Pablo da Costa; Viñuela, Elisa

    2016-07-01

    The predator Chrysoperla carnea is a model species for the study of non-target effects of pesticides under different scenarios: registration of plant protection products under the European Union and effects of the Bt toxin. Laboratory and persistence studies were carried out with six pesticides currently used in corn crops in Spain that were applied at their maximum field recommended concentrations. The assessed end-points were larval mortality, survivorship until adult stage, duration of the larval and pupal periods, fecundity, fertility and sex ratio of the emerged adults. Based on the total effect (lethal and sublethal) caused to L3 larvae in contact with fresh residues in the laboratory, pendimethalin was harmless (IOBC 1), lambda-cyhalothrin, abamectin, and hexythiazox were slightly harmful (IOBC 2), deltamethrin was moderately harmful (IOBC 3) and chlorpyrifos was harmful (IOBC 4). Afterwards, the residues of the two most toxic pesticides in the lab (deltamethrin and chlorpyrifos) were aged under greenhouse conditions (22 ± 2 °C, 40 ± 10 % R.H., 16.9 μmol m(-2) s(-1) UV radiation) in the presence and absence of artificial rainfall (10 l m(-2) h(-1), applied 24 h after pesticide application). Deltamethrin was classified as short lived (IOBC A) in both cases. However, degradation of chlorpyrifos residues was accelerated in the presence of rainfall, leading to the classification as slightly persistent (IOBC B), while in absence of rainfall it behaved as persistent (IOBC D). Every pesticide can be recommended for inclusion in corn IPM programs where the predator is present except chlorpyrifos that exhibited high direct toxicity in the lab and prolonged residual action even in the presence of rainfall.

  12. Initial Response of Pine Seedlings and Weeds to Dried Sewage Sludge in Rehabilitation of an Eroded Forest Site

    Science.gov (United States)

    Charles R. Berry

    1977-01-01

    Dried sewage sludge was applied at rates of 0, 17, 34, and 69 metric tons/ha on a badly eroded forest site in the Piedmont region of northeast Georgia. Production of weed bio mass varied directly with amount of sludge applied. Heigh growth for both shortleafand loblolly pine seedlings appeared to be greater on plots receiving 17 metric tons of sludge/ha, bu differences...

  13. The effects of the mineral phase on C stabilization mechanisms and the microbial community along an eroding slope transect

    Science.gov (United States)

    Doetterl, S.; Opfergelt, S.; Cornelis, J.; Boeckx, P. F.; van oost, K.; Six, J.

    2013-12-01

    An increasing number of studies show the importance of including soil redistribution processes in understanding carbon (C) dynamics in eroding landscapes. The quality and quantity of soil organic carbon in sloping cropland differs with topographic position. These differences are commonly more visible in the subsoil, while the size and composition of topsoil C pools are similar along the hillslope. The type (plant- or microbial-derived) and quality (level of degradation) of C found in a specific soil fraction depends on the interplay between the temporal dynamic of the specific mechanism and it's strength to protect C from decomposition. Here, we present an analysis that aims to clarify the bio/geo-chemical and mineralogical components involved in stabilizing C at various depths and slope positions and how they affect the microbial community and the degradation of C. For this we analyzed soil samples from different soil depths along a slope transect applying (i) a sequential extraction of the reactive soil phase using pyrophosphate, oxalate and dithionite-citrate-bicarbonate, (ii) a semi-quantitative and qualitative analysis of the clay mineralogy, (iii) an analysis of the microbial community using amino sugars and (iv) an analysis of the level of degradation of C in different soil fractions focusing on the soil Lignin signature. The results show that the pattern of minerals and their relative importance in stabilizing C varies greatly along the transect. In the investigated soils, pyrophosphate extractable Manganese, and not Iron or Aluminum as often observed, is strongly correlated to C in the bulk soil and in the non-aggregated silt and clay fractions. This suggests a certain role of Manganese for C stabilization where physical protection is absent. In contrast, pyrophosphate extractable Iron and Aluminum components are largely abundant in water-stable soil aggregates but not correlated to C, suggesting importance of these extracts to stabilize aggregates and

  14. Towards prediction of soil erodibility using hyperspectral information: a case study in a semi-arid region of Iran

    DEFF Research Database (Denmark)

    Ostovari, Yaser; Ghorbani-Dashtaki, Shoja; Bahrami, Hossein-Ali

    2018-01-01

    and develop Spectrotransfer Function (STF) using spectral reflectance information and Pedotransfer Function (PTF) to predict the K-factor, respectively. The derived STF was compared with developed PTF using measurable soil properties by Ostovari et al. (2016) and the Universal Soil Loss Equation (USLE......Soil Visible–Near-Infrared (Vis-NIR) spectroscopy has become an applicable and interesting technique to evaluate a number of soil properties because it is a fast, cost-effective, and non-invasive measurement technique. The main objective of the study to predict soil erodibility (K-factor), soil...... organic matter (SOM), and calcium carbonate equivalent (CaCO3) in calcareous soils of semi-arid regions located in south of Iran using spectral reflectance information in the Vis-NIR range. The K-factor was measured in 40 erosion plots under natural rainfall and the spectral reflectance of soil samples...

  15. Viability of sublethally injured coliform bacteria on fresh-cut cabbage stored in high CO2 atmospheres following rinsing with electrolyzed water.

    Science.gov (United States)

    Izumi, Hidemi; Inoue, Ayano

    2018-02-02

    The extent of sublethally injured coliform bacteria on shredded cabbage, either rinsed or not rinsed with electrolyzed water, was evaluated during storage in air and high CO 2 controlled atmospheres (5%, 10%, and 15%) at 5°C and 10°C using the thin agar layer (TAL) method. Sublethally injured coliform bacteria on nonrinsed shredded cabbage were either absent or they were injured at a 64-65% level when present. Rinsing of shredded cabbage with electrolyzed water containing 25ppm available chlorine reduced the coliform counts by 0.4 to 1.1 log and caused sublethal injury ranging from 42 to 77%. Pantoea ananatis was one of the species injured by chlorine stress. When shredded cabbage, nonrinsed or rinsed with electrolyzed water, was stored in air and high CO 2 atmospheres at 5°C for 7days and 10°C for 5days, coliform counts on TAL plates increased from 3.3-4.5 to 6.5-9.0 log CFU/g during storage, with the increase being greater at 10°C than at 5°C. High CO 2 of 10% and 15% reduced the bacterial growth on shredded cabbage during storage at 5°C. Although injured coliform bacteria were not found on nonrinsed shredded cabbage on the initial day, injured coliforms at a range of 49-84% were detected on samples stored in air and high CO 2 atmospheres at 5°C and 10°C. Injured cells were detected more frequently during storage at both temperatures irrespective of the CO 2 atmosphere when shredded cabbage was rinsed with electrolyzed water. These results indicated that injured coliform bacteria on shredded cabbage, either rinsed or not rinsed with electrolyzed water, exhibited different degrees of injury during storage regardless of the CO 2 atmosphere and temperature tested. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. A linear-quadratic model of cell survival considering both sublethal and potentially lethal radiation damage

    International Nuclear Information System (INIS)

    Rutz, H.P.; Coucke, P.A.; Mirimanoff, R.O.

    1991-01-01

    The authors assessed the dose-dependence of repair of potentially lethal damage in Chinese hamster ovary cells x-irradiated in vitro. The recovery ratio (RR) by which survival (SF) of the irradiated cells was enhanced increased exponentially with a linear and a quadratic component namely ζ and ψ: RR=exp(ζD+ψD 2 ). Survival of irradiated cells can thus be expressed by a combined linear-quadratic model considering 4 variables, namely α and β for the capacity of the cells to accumulate sublethal damage, and ζ and ψ for their capacity to repair potentially lethal damage: SF=exp((ζ-α)D+ (ψ-β)D 2 ). author. 26 refs.; 1 fig.; 1 tab

  17. Induction of high tolerance to artemisinin by sub-lethal administration: A new in vitro model of P. falciparum.

    Directory of Open Access Journals (Sweden)

    Serena De Lucia

    Full Text Available Artemisinin resistance is a major threat to malaria control efforts. Resistance is characterized by an increase in the Plasmodium falciparum parasite clearance half-life following treatment with artemisinin-based combination therapies (ACTs and an increase in the percentage of surviving parasites. The remarkably short blood half-life of artemisinin derivatives may contribute to drug-resistance, possibly through factors including sub-lethal plasma concentrations and inadequate exposure. Here we selected for a new strain of artemisinin resistant parasites, termed the artemisinin resistant strain 1 (ARS1, by treating P. falciparum Palo Alto (PA cultures with sub-lethal concentrations of dihydroartemisinin (DHA. The resistance phenotype was maintained for over 1 year through monthly maintenance treatments with low doses of 2.5 nM DHA. There was a moderate increase in the DHA IC50 in ARS1 when compared with parental strain PA after 72 h of drug exposure (from 0.68 nM to 2 nM DHA. In addition, ARS1 survived treatment physiologically relevant DHA concentrations (700 nM observed in patients. Furthermore, we confirmed a lack of cross-resistance against a panel of antimalarials commonly used as partner drugs in ACTs. Finally, ARS1 did not contain Pfk13 propeller domain mutations associated with ART resistance in the Greater Mekong Region. With a stable growth rate, ARS1 represents a valuable tool for the development of new antimalarial compounds and studies to further elucidate the mechanisms of ART resistance.

  18. Spatially variable rock erodibility in bedrock channels undergoing transient response to baselevel change, Great Falls area, Virginia

    OpenAIRE

    Shobe, Charles; Kee, Connor; Hancock, Gregory

    2018-01-01

    This is a poster that was presented in April 2014 at the Geological Society of America southeastern section meeting in Blacksburg, VA, USA. The poster presents rock strength and roughness data from tributaries to the Potomac River in Virginia. Our data support the idea that bedrock channel erodibility is greater on the channel margins than at the thalweg, which we hypothesize to be the result of weathering damage preferentially accumulated on the channel banks. This work was published in Shob...

  19. Lethal and sublethal effects of selected insecticides and an insect growth regulator on the boll weevil (Coleoptera: Curculionidae) ectoparasitoid Catolaccus grandis (Hymenoptera: Pteromalidae).

    Science.gov (United States)

    Elzen, G W; Maldonado, S N; Rojas, M G

    2000-04-01

    A laboratory culture of Catolaccus grandis (Burks), an ectoparasitoid of the boll weevil, Anthonomus grandis grandis Boheman, was exposed to lethal and sublethal doses of insecticides and an insect growth regulator using a spray chamber bioassay. Materials tested were azinphos-methyl, endosulfan, fipronil, malathion, cyfluthrin, dimethoate, spinosad, methyl parathion, acephate, oxamyl, and tebufenozide. At full rates, spinosad was significantly less toxic to female C. grandis than other treatments except endosulfan. Fipronil and malathion were significantly more toxic to females than other treatments. Most of the chemicals tested were highly toxic to male C. grandis; spinosad was least toxic. At reduced rates, most of 4 selected chemicals tested were low in toxicity to C. grandis; however, a reduced rate of malathion was significantly more toxic to females than other treatments. No C. grandis pupae developed from parasitism during a 24-h treatment period with malathion or spinosad. The sex ratio of progeny from sprayed adults appeared to be unaffected by the treatments.

  20. Study of Engraftment of human cord blood cells to rescue the sublethal radiation damage mice

    International Nuclear Information System (INIS)

    Cao Xiangshan; Zou Zhenghui; Yu Fei; Zhang Zhilin; Lin Baojue

    1997-01-01

    To investigate alternative source of hematopoiesis stem cells to rescue the sublethal radiation damage (SRD) casualties. Human-umbilical cord blood hematopoietic cells were transplanted into SRD mice, the survival rate and the hematopoiesis reconstitution of bone marrow were assessed. The survival rate, in the mice transplanted and the untransplanted, were 90% and 10% respectively. Bone marrow and spleen of survival mice showed human leukocytic antigen CD45 + cells. Presence of multilineage engraftment, including myeloid and erythroid lineages, were found indicating that immature human cells home to the mouse bone marrow. conclusion: engraftment of umbilical cord blood cells is very useful to reconstitute hematopoiesis of SRD casualties. As cord blood has many advantages over bone marrow and peripheral blood, it is important in rescuing radiation accidental casualties

  1. The SOS response increases bacterial fitness, but not evolvability, under a sublethal dose of antibiotic.

    Science.gov (United States)

    Torres-Barceló, Clara; Kojadinovic, Mila; Moxon, Richard; MacLean, R Craig

    2015-10-07

    Exposure to antibiotics induces the expression of mutagenic bacterial stress-response pathways, but the evolutionary benefits of these responses remain unclear. One possibility is that stress-response pathways provide a short-term advantage by protecting bacteria against the toxic effects of antibiotics. Second, it is possible that stress-induced mutagenesis provides a long-term advantage by accelerating the evolution of resistance. Here, we directly measure the contribution of the Pseudomonas aeruginosa SOS pathway to bacterial fitness and evolvability in the presence of sublethal doses of ciprofloxacin. Using short-term competition experiments, we demonstrate that the SOS pathway increases competitive fitness in the presence of ciprofloxacin. Continued exposure to ciprofloxacin results in the rapid evolution of increased fitness and antibiotic resistance, but we find no evidence that SOS-induced mutagenesis accelerates the rate of adaptation to ciprofloxacin during a 200 generation selection experiment. Intriguingly, we find that the expression of the SOS pathway decreases during adaptation to ciprofloxacin, and this helps to explain why this pathway does not increase long-term evolvability. Furthermore, we argue that the SOS pathway fails to accelerate adaptation to ciprofloxacin because the modest increase in the mutation rate associated with SOS mutagenesis is offset by a decrease in the effective strength of selection for increased resistance at a population level. Our findings suggest that the primary evolutionary benefit of the SOS response is to increase bacterial competitive ability, and that stress-induced mutagenesis is an unwanted side effect, and not a selected attribute, of this pathway. © 2015 The Authors.

  2. Numerical Investigation of Temperature Distribution in an Eroded Bend Pipe and Prediction of Erosion Reduced Thickness

    Science.gov (United States)

    Zhu, Hongjun; Feng, Guang; Wang, Qijun

    2014-01-01

    Accurate prediction of erosion thickness is essential for pipe engineering. The objective of the present paper is to study the temperature distribution in an eroded bend pipe and find a new method to predict the erosion reduced thickness. Computational fluid dynamic (CFD) simulations with FLUENT software are carried out to investigate the temperature field. And effects of oil inlet rate, oil inlet temperature, and erosion reduced thickness are examined. The presence of erosion pit brings about the obvious fluctuation of temperature drop along the extrados of bend. And the minimum temperature drop presents at the most severe erosion point. Small inlet temperature or large inlet velocity can lead to small temperature drop, while shallow erosion pit causes great temperature drop. The dimensionless minimum temperature drop is analyzed and the fitting formula is obtained. Using the formula we can calculate the erosion reduced thickness, which is only needed to monitor the outer surface temperature of bend pipe. This new method can provide useful guidance for pipeline monitoring and replacement. PMID:24719576

  3. Toxicity and sublethal effects of six insecticides to last instar larvae and adults of the biocontrol agents Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and Adalia bipunctata (L.) (Coleoptera: Coccinellidae).

    Science.gov (United States)

    Garzón, A; Medina, P; Amor, F; Viñuela, E; Budia, F

    2015-08-01

    To further develop Integrated Pest Management (IPM) strategies against crop pests, it is important to evaluate the effects of insecticides on biological control agents. Therefore, we tested the toxicity and sublethal effects (fecundity and fertility) of flonicamid, flubendiamide, metaflumizone, spirotetramat, sulfoxaflor and deltamethrin on the natural enemies Chrysoperla carnea and Adalia bipunctata. The side effects of the active ingredients of the insecticides were evaluated with residual contact tests for the larvae and adults of these predators in the laboratory. Flonicamid, flubendiamide, metaflumizone and spirotetramat were innocuous to last instar larvae and adults of C. carnea and A. bipunctata. Sulfoxaflor was slightly toxic to adults of C. carnea and was highly toxic to the L4 larvae of A. bipunctata. For A. bipunctata, sulfoxaflor and deltamethrin were the most damaging compounds with a cumulative larval mortality of 100%. Deltamethrin was also the most toxic compound to larvae and adults of C. carnea. In accordance with the results obtained, the compounds flonicamid, flubendiamide, metaflumizone and spirotetramat might be incorporated into IPM programs in combination with these natural enemies for the control of particular greenhouse pests. Nevertheless, the use of sulfoxaflor and deltamethrin in IPM strategies should be taken into consideration when releasing either of these biological control agents, due to the toxic behavior observed under laboratory conditions. The need for developing sustainable approaches to combine the use of these insecticides and natural enemies within an IPM framework is discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. 1H NMR-based metabolomics of time-dependent responses of Eisenia fetida to sub-lethal phenanthrene exposure

    International Nuclear Information System (INIS)

    Lankadurai, Brian P.; Wolfe, David M.; Simpson, Andre J.; Simpson, Myrna J.

    2011-01-01

    1 H NMR-based metabolomics was used to examine the response of the earthworm Eisenia fetida after exposure to sub-lethal concentrations of phenanthrene over time. Earthworms were exposed to 0.025 mg/cm 2 of phenanthrene (1/64th of the LC 50 ) via contact tests over four days. Earthworm tissues were extracted using a mixture of chloroform, methanol and water, resulting in polar and non-polar fractions that were analyzed by 1 H NMR after one, two, three and four days. NMR-based metabolomic analyses revealed heightened E. fetida responses with longer phenanthrene exposure times. Amino acids alanine and glutamate, the sugar maltose, the lipids cholesterol and phosphatidylcholine emerged as potential indicators of phenanthrene exposure. The conversion of succinate to fumarate in the Krebs cycle was also interrupted by phenanthrene. Therefore, this study shows that NMR-based metabolomics is a powerful tool for elucidating time-dependent relationships in addition to the mode of toxicity of phenanthrene in earthworm exposure studies. - Highlights: → NMR-based earthworm metabolomic analysis of the mode of action of phenanthrene is presented. → The earthworm species E. fetida were exposed to sub-lethal phenanthrene concentrations. → Both polar and non-polar metabolites of E. fetida tissue extracts were analyzed by 1 H NMR. → Longer phenanthrene exposure times resulted in heightened earthworm responses. → An interruption of the Krebs cycle was also observed due to phenanthrene exposure. - 1 H NMR metabolomics is used to determine the relationship between phenanthrene exposure and the metabolic response of the earthworm E. fetida over time and also to elucidate the phenanthrene mode of toxicity.

  5. Assessment of Mercury Bioaccumulation in Zebra Cichlid (Cichlasoma Nigrofasciatum Exposed to Sublethal Concentrations of Permethrin

    Directory of Open Access Journals (Sweden)

    Mahdi Banaee

    2014-12-01

    Full Text Available Background: Aquatic ecosystems are frequently subjected to contamination by toxic heavy metals and pesticides, yet very little is known about the influence of pesticides on bioaccumulation of heavy metals in aquatic organisms. Mercury is a toxic metal with no known biological benefit to organisms. Bioavailability of mercury in aquatic environments depends on biological and non-biological parameters including other pollutants. Therefore, the objectives of this research were to determine the effects of permethrin on bioaccumulation of mercury in zebra cichlid. Methods: Acute toxicity (LC50 of permethrin and mercury chloride was evaluated by estimating mortality in Probit Model in SPSS (version 19.0 IBM. In sub-lethal toxicity, zebra cichlid (Cichlasoma nigrofasciatum was exposed to various concentrations of permethrin (0.0, 0.40, 0.80, 1.20 and 1.60 µg.L-1 combined with 20 µg.L-1 mercury chloride for 15 days. At the end of the experiment, mercury concentrations were measured using ICP-OES-Perkin elmer (optima 7300-DV. Results: 96 h LC50 values of permethrin and mercury for C. nigrofasciatum were calculated to be 17.55 µg.L-1 and 140.38 µg.L-1, respectively. Our results clearly showed that the bioaccumulation of mercury in the specimens increased with increasing concentrations of permethrin to 1.20 and 1.60 µg.L-1. Conclusion: Increasing the concentration of permethrin had synergistic effects on the bioaccumulation of mercury in fish.

  6. Reconstruction of eroded and deposited sediment volumes in the floodplains of the embanked River Waal, the Netherlands, for the period 1650 - 1850 AD

    Science.gov (United States)

    Hobo, Noortje; Makaske, Bart; Middelkoop, Hans

    2010-05-01

    The embanked floodplains of the River Waal developed as a result of stepwise downstream migration of meander bends between confining dykes. Accretion in the upstream limb of the outer bend - enhanced by groynes and trees - and erosion in the downstream limb have resulted in a series of successively developed sand bars, separated by secondary channels. On top of the sand bars and the secondary channel fills, fine-grained overbank sediments were deposited. Downstream migration ceased around 1850 AD, when the river bed was fixed by large-scale construction of groynes, and only overbank deposition continued. Eroded and deposited sediment volumes associated with downstream migration are affected by human activities. Goal of the present research is to estimate a sediment budget for a 12-km-long section along the River Waal, by quantifying the amount of erosion and deposition. We estimated these volumes for time slices of 50 years, between 1650 and 1850 AD, in order to be able to assess the variable impact of human interference during this period. To estimate erosion, we created geomorphological maps for all time slices, based on maps dating from the 17th century to present. In these maps, distinction is made between sand bars, residual channels, and older deposits (all sediments deposited before 1650 AD). Comparison between all maps allowed us to calculate the eroded area per time slice. Eroded volumes were hence estimated by multiplying the eroded area by the average river depth at that period, which is assumed to be the erosion depth. For estimation of deposition we used lithological cross-sections. These cross-sections are positioned such that every sand bar and every residual channel is represented in at least one cross-section. In every cross-section isochrones were drawn, based on OSL datings, chronologic interpretation of heavy metal profiles, and the historical maps. These isochrones are used to calculate the thickness of the sand bars, the residual channel fills

  7. Effect of haemopoietic system activation on radiosensitivity of animals

    International Nuclear Information System (INIS)

    Bitny-Szlachto, S.

    1985-01-01

    The aim of these investigations was to study the influence of activation of erythropoiesis by carbon monoxide, blood letting and blood transfuzing, hypobaric hypoxia, fenylohydrazine induced hemolysis, pertussis vaccine and also sublethal irradiation and later polycythemia on the blood-forming system's ability to postirradiation regeneration after lethal and sublethal X ray irradiation on the whole body of mouse. Results were positive except pertusis vaccine which caused considerable decrease in survival of irradiated mice. Ionizing radiation and fenylohydrazine were the most effective. 21 refs.,5 tabs. (author)

  8. Therapeutic effects of the joint administration of magnesium aspartate and adenosine monophosphate in gamma-irradiated mice

    International Nuclear Information System (INIS)

    Pospisil, M.; Netikova, J.; Pipalova, I.; Kozubik, A.

    1990-01-01

    The joint administration of magnesium aspartate and adenosine monophosphate, injected on days 1 to 4 post radiation, has been found to exert stimulatory effects on the recovery of hemopoietic functions in sublethally gamma-irradiated mice. These therapeutical effects were enhanced in animals protected by peroral administration of cystamine. The treatment scheme used did not modify survival of lethally irradiated mice. The therapeutic effects of magnesium aspartate and adenosine monophosphate in sublethally irradiated mice are explained by the stimulatory action of these drugs on the cell adenylate cyclase system, which influences the erythropoietic functions. (author)

  9. Immunotherapy with mutated onchocystatin fails to enhance the efficacy of a sub-lethal oxytetracycline regimen against Onchocerca ochengi.

    Science.gov (United States)

    Bah, Germanus S; Tanya, Vincent N; Makepeace, Benjamin L

    2015-08-15

    Human onchocerciasis (river blindness), caused by the filarial nematode Onchocerca volvulus, has been successfully controlled by a single drug, ivermectin, for over 25 years. Ivermectin prevents the disease symptoms of severe itching and visual impairment by killing the microfilarial stage, but does not eliminate the adult parasites, necessitating repeated annual treatments. Mass drug administration with ivermectin does not always break transmission in forest zones and is contraindicated in individuals heavily co-infected with Loa loa, while reports of reduced drug efficacy in Ghana and Cameroon may signal the development of resistance. An alternative treatment for onchocerciasis involves targeting the essential Wolbachia symbiont with tetracycline or its derivatives, which are adulticidal. However, implementation of antibiotic therapy has not occurred on a wide scale due to the prolonged treatment regimen required (several weeks). In the bovine Onchocerca ochengi system, it has been shown previously that prolonged oxytetracycline therapy increases eosinophil counts in intradermal nodules, which kill the adult worms by degranulating on their surface. Here, in an "immunochemotherapeutic" approach, we sought to enhance the efficacy of a short, sub-lethal antibiotic regimen against O. ochengi by prior immunotherapy targeting onchocystatin, an immunomodulatory protein located in the adult female worm cuticle. A key asparagine residue in onchocystatin was mutated to ablate immunomodulatory activity, which has been demonstrated previously to markedly improve the protective efficacy of this vaccine candidate when used as an immunoprophylactic. The immunochemotherapeutic regimen was compared with sub-lethal oxytetracycline therapy alone; onchocystatin immunotherapy alone; a gold-standard prolonged, intermittent oxytetracycline regimen; and no treatment (negative control) in naturally infected Cameroonian cattle. Readouts were collected over one year and comprised adult

  10. Cellular adverse actions of dibromoacetonitrile, a by-product in water bacterial control, at sublethal levels in rat thymocytes.

    Science.gov (United States)

    Kishida, Takumi; Akiyoshi, Kenji; Erdenedalai, Erdenebat; Enhetomuru, Anu; Imai, Shoji; Oyama, Yasuo

    2018-09-01

    The aim of this study was to investigate the effects of dibromoacetonitrile (DBAN), a by-product in water bacterial control, at sublethal concentrations on rat thymocytes, by using a cytometric technique with appropriate fluorescent dyes. By using this method, the possibility that DBAN induces cellular actions related to oxidative stress was assessed. DBAN reduced the content of cellular nonprotein thiols under Zn 2+ -free conditions. It elevated the intracellular level of Zn 2+ , being independent from external Zn 2+ . DBAN increased cell vulnerability to the cytotoxic action of hydrogen peroxide. These actions of DBAN were likely related to oxidative stress. DBAN is formed by the reaction of bromides and chlorinated oxidants during water disinfection. Hydrolysis of 2,2-dibromo-3-nitrilopropionamide, an antimicrobial used in hydraulic fracturing fluids for production of shale gas and oil, produces DBAN. Therefore, the concern regarding the levels of DBAN in industrial water systems is necessary to avoid the environmental risk to humans and wild mammals. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Thymic nurse cells and thymic repopulation after whole body sublethal irradiation in mice

    International Nuclear Information System (INIS)

    Houben-Defresne, M.P.; Varlet, A.; Boniver, J.

    1984-01-01

    Thymic Nurse Cells (TNCs) are lymphoepithelial complexes which are thought to play a role in the early stages of the intrathymic differentiation pathway. Their repopulation kinetics were analyzed in mice after sublethal whole-body irradiation. Changes of the number of TNCs per thymus were parallel with the evolution of the whole thymocyte population. Particularly, a first wave of TNCs restoration was followed by a secondary depletion and a final recovery. This suggests that TNCs restoration is related to the proliferating progeny of intrathymic radioresistant thymocytes. When normal bone marrow cells were grafted intravenously after irradiation, no secondary depletion was found. This pattern of restoration was obviously related to thymic repopulation by cells which were derived from the inoculated bone marrow. Homing studies with FITC labelled bone marrow cells showed that inoculated bone marrow cells did not penetrate TNCs early after irradiation. Later on, when immigrant cells started to proliferate, they were found preferentially within TNCs before spreading in the whole thymus. (Auth.)

  12. Sub-lethal cadmium exposure increases phytochelatin concentrations in the aquatic snail Lymnaea stagnalis

    Energy Technology Data Exchange (ETDEWEB)

    SF, Gonçalves [Department of Biology & CESAM, Centre for Environmental and Marine Studies, University of Aveiro, 3810-193 Aveiro (Portugal); SK, Davies [Department of Surgery and Cancer, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ (United Kingdom); Bennett, M. [Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ (United Kingdom); Raab, A.; Feldmann, J. [TESLA, Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland (United Kingdom); Kille, P. [Cardiff School of Biosciences, Cardiff University, Park Place, Cardiff CF10 3US (United Kingdom); Loureiro, S. [Department of Biology & CESAM, Centre for Environmental and Marine Studies, University of Aveiro, 3810-193 Aveiro (Portugal); DJ, Spurgeon [Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford OX10 8BB (United Kingdom); JG, Bundy, E-mail: j.bundy@imperial.ac.uk [Department of Surgery and Cancer, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ (United Kingdom)

    2016-10-15

    Phytochelatins are metal-binding metabolites found in almost all plant species and some animal groups, including nematodes and annelids, where they can play an important role in detoxifying metals such as cadmium. Species from several other taxa contain a phytochelatin synthase (PCS) gene orthologue, including molluscs, indicating they may have the potential to synthesize phytochelatins. However, the presence of a gene alone does not demonstrate that it plays a functional role in metal detoxification. In the present study, we show that the aquatic snail Lymnaea stagnalis produced both penta- and heptapeptide phytochelatins (i.e. phytochelatin-2 and phytochelatin-3), and their levels increased in response to sub-lethal levels of cadmium. - Highlights: • Little is known about the role of phytochelatins in metal detoxification in animals. • We detected phytochelatins (PC{sub 2} and PC{sub 3}) in a mollusc species, Lymnaea stagnalis. • Phytochelatins increased in Lymnaea stagnalis when exposed to cadmium. • Future research on phytochelatin responses in molluscs would be valuable.

  13. Highly erodible terrain in agriculture land against chipped pruned branches. Or how to stop the soil erosion with low investment

    Science.gov (United States)

    Cerdà, A.

    2009-04-01

    The session on "Soil erosion and sediment control with vegetation and bioengineering on severely eroded terrain" pays special attention to the severe soil erosion suffered on steep slopes and erodible parent materials and soils. Within the last 20 years, in the Mediterranean lands, the citrus orchards were reallocated on steep slopes due to the urban development and better climatic and management conditions of the new plantations. The lack of vegetation cover on the new slope plantations of citrus resulted in high erosion rates. Those non-sustainable soil losses were measured by means of rainfall simulation experiments, Gerlach collectors, geomorphological transect and topographical measurements. The October 2007 and October 2008 rainy periods resulted in sheet, rill and gully erosion. Some recently planted orchards (2005) had the first pruning season in 2008. The pruned chipped branches reduced the soil losses to 50 % of the expected, although the litter (pruned branches) covered 4.67 % of the soil. This is why a research was developed by means of simulated rainfall experiments to determine the vegetation cover (litter, mainly leaves) to protect the soil to reach a sustainable erosion rate. Rainfall simulation experiments at 43 mm h-1 where performed on 1 m2 plots covered with 0, 3, 7, 15, 30, 45, 60, 80 and 100 % litter cover (pruned chipped branches) to determine the sustainable litter cover to avoid the soil losses. The results show that more that 45 % litter cover almost reduces the soil losses to negligible rates. The results confirm that 4 % of vegetation cover reduces the soil losses to 50 %. Key words: Agriculture land, erodible terrain, land management, citrus, erosion, Spain, Valencia, herbicides. Acknowledgements, We thanks the financial support of the Ministerio de Ciencia e Innovación by means of the project CGL2008-02879/BTE, "PERDIDA DE SUELO EN NUEVAS EXPLOTACIONES CITRICOLAS EN PENDIENTE. ESTRATEGIAS PARA EL CONTROL DE LA EROSION HIDRICA"

  14. Estimativa da erodibilidade pela desagregação por ultra-som e atributos de solos com horizonte B textural Estimating soil erodibility from sonication indexes and other attributes of textural B horizon soils

    Directory of Open Access Journals (Sweden)

    Marcos Aurélio Carolino de Sá

    2004-07-01

    Full Text Available A erodibilidade de solos é um fator importante na estimativa das perdas por erosão. Este fator é uma expressão da combinação de atributos do solo, os quais possibilitam sua estimativa por meio de equações. O objetivo deste trabalho foi medir atributos químicos e mineralógicos que, combinados com índices de estabilidade de agregados determinados por ultra-som, pudessem ser utilizados como variáveis em modelos na estimativa da erodibilidade de solos com horizonte B textural do Brasil. Estes atributos foram determinados em 22 solos de erodibilidade conhecida, medida diretamente em parcelas no campo. Atributos de 21 dos solos foram utilizados no ajuste dos modelos. Um dos solos (Argissolo Vermelho-Amarelo foi escolhido ao acaso para teste. De 96 variáveis, 15 foram incluídas nos modelos de estimativa da erodibilidade. A maioria delas é representada por índices de desagregação por sonificação de amostras do horizonte A. Foram obtidos quatro modelos para estimar a erodibilidade, com R² variando entre 0,83** e 0,91**. A erodibilidade pode ser estimada com base na estabilidade de agregados por ultra-som.Soil erodibility is an important factor for estimating soil erosion losses. This factor is an expression of combined soil attributes, which make possible its estimation by equations. The objective of this study was to measure some chemical and mineralogical attributes, and to combine them with aggregate stability indexes from sonication analysis, in equations in order to estimate soil erodibility of textural B horizon soils from Brazil. These attributes were measured for 22 soils that had their erodibility measured from field plots. Attributes of 21 soils were used to adjust the equations. One of the soils (Red-Yellow Argisol was used to test the equations. From 96 variables, 15 were significantly correlated to soil erodibility. Most of them are represented by the disruption indexes from sonication analysis of A horizon samples. This

  15. {sup 1}H NMR-based metabolomics of time-dependent responses of Eisenia fetida to sub-lethal phenanthrene exposure

    Energy Technology Data Exchange (ETDEWEB)

    Lankadurai, Brian P.; Wolfe, David M.; Simpson, Andre J. [Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario M1C 1A4 Canada (Canada); Simpson, Myrna J., E-mail: myrna.simpson@utoronto.ca [Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario M1C 1A4 Canada (Canada)

    2011-10-15

    {sup 1}H NMR-based metabolomics was used to examine the response of the earthworm Eisenia fetida after exposure to sub-lethal concentrations of phenanthrene over time. Earthworms were exposed to 0.025 mg/cm{sup 2} of phenanthrene (1/64th of the LC{sub 50}) via contact tests over four days. Earthworm tissues were extracted using a mixture of chloroform, methanol and water, resulting in polar and non-polar fractions that were analyzed by {sup 1}H NMR after one, two, three and four days. NMR-based metabolomic analyses revealed heightened E. fetida responses with longer phenanthrene exposure times. Amino acids alanine and glutamate, the sugar maltose, the lipids cholesterol and phosphatidylcholine emerged as potential indicators of phenanthrene exposure. The conversion of succinate to fumarate in the Krebs cycle was also interrupted by phenanthrene. Therefore, this study shows that NMR-based metabolomics is a powerful tool for elucidating time-dependent relationships in addition to the mode of toxicity of phenanthrene in earthworm exposure studies. - Highlights: > NMR-based earthworm metabolomic analysis of the mode of action of phenanthrene is presented. > The earthworm species E. fetida were exposed to sub-lethal phenanthrene concentrations. > Both polar and non-polar metabolites of E. fetida tissue extracts were analyzed by {sup 1}H NMR. > Longer phenanthrene exposure times resulted in heightened earthworm responses. > An interruption of the Krebs cycle was also observed due to phenanthrene exposure. - {sup 1}H NMR metabolomics is used to determine the relationship between phenanthrene exposure and the metabolic response of the earthworm E. fetida over time and also to elucidate the phenanthrene mode of toxicity.

  16. Sublethal effects of tritium on aquatic systems

    International Nuclear Information System (INIS)

    Strand, J.A.; Poston, T.M.

    1982-01-01

    It is the purpose of this continuing study to determine the relative biological effectiveness (RBE) of 3 H-beta irradiation when compared to 60 Co-gamma irradiation applying the relatively radiosensitive immune process of the rainbow trout, Salmo gairdneri. This study is also designed to investigate the nature of latent expression of immune incompetence in trout exposed to 3 H-irradiation during embryogenesis

  17. Restoration of eroded soil in the Sonoran Desert with native leguminous trees using plant growth-promoting microorganisms and limited amounts of compost and water.

    Science.gov (United States)

    Bashan, Yoav; Salazar, Bernardo G; Moreno, Manuel; Lopez, Blanca R; Linderman, Robert G

    2012-07-15

    Restoration of highly eroded desert land was attempted in the southern Sonoran Desert that had lost its natural capacity for self-revegetation. In six field experiments, the fields were planted with three native leguminous trees: mesquite amargo Prosopis articulata, and yellow and blue palo verde Parkinsonia microphylla and Parkinsonia florida. Restoration included inoculation with two of plant growth-promoting bacteria (PGPB; Azospirillum brasilense and Bacillus pumilus), native arbuscular mycorrhizal (AM) fungi, and small quantities of compost. Irrigation was applied, when necessary, to reach a rainy year (300 mm) of the area. The plots were maintained for 61 months. Survival of the trees was marginally affected by all supplements after 30 months, in the range of 60-90%. This variation depended on the plant species, where all young trees were established after 3 months. Plant density was a crucial variable and, in general, low plant density enhanced survival. High planting density was detrimental. Survival significantly declined in trees 61 months after planting. No general response of the trees to plant growth-promoting microorganisms and compost was found. Mesquite amargo and yellow palo verde responded well (height, number of branches, and diameter of the main stem) to inoculation with PGPB, AM fungi, and compost supplementation after three months of application. Fewer positive effects were recorded after 30 months. Blue palo verde did not respond to most treatments and had the lowest survival. Specific plant growth parameters were affected to varying degrees to inoculations or amendments, primarily depending on the tree species. Some combinations of tree/inoculant/amendment resulted in small negative effects or no response when measured after extended periods of time. Using native leguminous trees, this study demonstrated that restoration of severely eroded desert lands was possible. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Qualification of spontaneous undirected locomotor behavior of fish for sublethal toxicity testing. Part 2. Variability of measurement parameters under toxicant-induced stress

    Energy Technology Data Exchange (ETDEWEB)

    Grillitsch, B.; Vogl, C.; Wytek, R.

    1999-12-01

    Spontaneous locomotor behavior of semiadult zebra fish (Brachydanio rerio) was recorded under sublethal short-term exposure to the anionic technical surfactant, linear alkylbenzene sulfonate (C{sub 10-13}-LAS) and cadmium in single compound tests using an automated video-monitoring and object-tracing system. Vertical position and swimming velocity in the horizontal and vertical directions were used as behavioral measurement parameters. Data were analyzed by different statistical methods. In pairwise comparisons, consistent, statistically significant, and toxicant-induced alterations of locomotor behavior were observed only for test concentrations, which also caused aspectoric symptoms of intoxication. This comparatively low sensitivity of the behavioral indication criteria was related to high variation in the measurement parameters and corresponding high, minimum detectable, statistically significant, and toxicant-induced deviations. In contrast, results obtained by regression analysis showed significant trends in locomotor activity over the range of toxicant concentrations tested. Thus, the findings support the inappropriateness of no observed effect concentrations and the lowest observed effect concentrations as summary measures of toxicity and indicate that the regression analysis approach is superior to the analysis of variance approach.

  19. A biomarker model of sublethal genotoxicity (DNA single-strand breaks and adducts) using the sentinel organism Aporrectodea longa in spiked soil

    International Nuclear Information System (INIS)

    Martin, Francis L.; Piearce, Trevor G.; Hewer, Alan; Phillips, David H.; Semple, Kirk T.

    2005-01-01

    There is a need to develop risk biomarkers during the remediation of contaminated land. We employed the earthworm, Aporrectodea longa (Ude), to determine whether genotoxicity measures could be applied to this organism's intestinal tissues. Earthworms were added, for 24 h or 7 days, to soil samples spiked with benzo[a]pyrene (B[a]P) and/or lindane. After exposure, intestinal tissues (crop/gizzard or intestine) were removed prior to the measurement in disaggregated cells of DNA single-strand breaks (SSBs) by the alkaline comet assay. Damage was quantified by comet tail length (CTL, μm). B[a]P 24-h exposure induced dose-related increases (P 32 P-postlabelling, showed a two-adduct-spot pattern. This preliminary investigation suggests that earthworm tissues may be incorporated into genotoxicity assays to facilitate hazard identification within terrestrial ecosystems. - Sublethal genotoxicity in the sentinel organism A. longa can be used to monitor the effects of contaminants in soil

  20. Erodibility of cement-stabilized tropical soils in highway engineering in Togo

    International Nuclear Information System (INIS)

    Eklu-Natey, T.E.D.

    1992-01-01

    This work contains a methodical study on the suceptibility to weather of cement-stabilized tropical soils of Togo by simulating on the one hand the climatic conditions of the original surroundings and on the other hand the variations occuring in situ of the degree of saturation and compaction. The chosen tests ensure for the first time a simple execution and at the same time reproducible numerical values of the results achieved. From results of the slaking, erosion, adhesion, durability and swelling tests clear parameters and classification criteria were derived which help to forecast the susceptibility to weather of soils in tropical climates. A method for the determination of the reaction to water of soils is proposed consisting of a particular process of derivation and interpretation of the consistency value for a given swelling rate. Moreover a possibility is recommended with which the time-consuming and expensive mineralogical analyses which were frequently used in the past for torpical soils can be avoided. The proposed evaluation criteria provides civil engineers working in permanently moist, arid or intermittently moist tropical regions with practical and theoretical bases for the estimation of the erodibility of soils. (orig./BBR) [de

  1. Toxic and hormetic-like effects of three components of citrus essential oils on adult Mediterranean fruit flies (Ceratitis capitata.

    Directory of Open Access Journals (Sweden)

    Stella A Papanastasiou

    Full Text Available Plant essential oils (EOs and a wide range of their individual components are involved in a variety of biological interactions with insect pests including stimulatory, deterrent, toxic and even hormetic effects. Both the beneficial and toxic properties of citrus EOs on the Mediterranean fruit fly (medfly have been experimentally evidenced over the last years. However, no information is available regarding the toxic or beneficial effects of the major components of citrus EOs via contact with the adults of the Mediterranean fruit fly. In the present study, we explored the toxicity of limonene, linalool and α-pinene (3 of the main compounds of citrus EOs against adult medflies and identified the effects of sub-lethal doses of limonene on fitness traits in a relaxed [full diet (yeast and sugar] and in a stressful (sugar only feeding environment. Our results demonstrate that all three compounds inferred high toxicity to adult medflies regardless of the diet, with males being more sensitive than females. Sub-lethal doses of limonene (LD20 enhanced the lifespan of adult medflies when they were deprived of protein. Fecundity was positively affected when females were exposed to limonene sub-lethal doses. Therefore, limonene, a major constituent of citrus EOs, induces high mortality at increased doses and positive effects on life history traits of medfly adults through contact at low sub-lethal doses. A hormetic-like effect of limonene to adult medflies and its possible underlying mechanisms are discussed.

  2. High hydrostatic pressure resistance of Campylobacter jejuni after different sublethal stresses.

    Science.gov (United States)

    Sagarzazu, N; Cebrián, G; Condón, S; Mackey, B; Mañas, P

    2010-07-01

    To study the development of resistance responses in Campylobacter jejuni to high hydrostatic pressure (HHP) treatments after the exposure to different stressful conditions that may be encountered in food-processing environments, such as acid pH, elevated temperatures and cold storage. Campylobacter jejuni cells in exponential and stationary growth phase were exposed to different sublethal stresses (acid, heat and cold shocks) prior to evaluate the development of resistance responses to HHP. For exponential-phase cells, neither of the conditions tested increased nor decreased HHP resistance of C. jejuni. For stationary-phase cells, acid and heat adaptation-sensitized C. jejuni cells to the subsequent pressure treatment. On the contrary, cold-adapted stationary-phase cells developed resistance to HHP. Whereas C. jejuni can be classified as a stress sensitive micro-organism, our findings have demonstrated that it can develop resistance responses under different stressing conditions. The resistance of stationary phase C. jejuni to HHP was increased after cells were exposed to cold temperatures. The results of this study contribute to a better knowledge of the physiology of C. jejuni and its survival to food preservation agents. Results here presented may help in the design of combined processes for food preservation based on HHP technology. © 2009 The Authors. Journal compilation © 2009 The Society for Applied Microbiology.

  3. Testing the ecotoxicology of vegetable versus mineral based lubricating oils: 2. Induction of mixed function oxidase enzymes in barramundi, Lates calcarifer, a tropical fish species

    International Nuclear Information System (INIS)

    Mercurio, Philip; Burns, Kathryn A.; Cavanagh, Joanne

    2004-01-01

    An increasing number of vegetable-based oils are being developed as environmentally friendly alternatives to petroleum products. However, toxicity towards key tropical marine species has not been investigated. In this study we used laboratory-based biomarker induction experiments to compare the relative stress of a vegetable-based lubricating oil for marine 2-stroke engines with its mineral oil-based counterpart on tropical fish. The sub-lethal stress of 2-stoke outboard lubricating oils towards the fish Lates calcarifer (barramundi) was examined using liver microsomal mixed function oxidase (MFO) induction assays. This study is the first investigation into the use of this key commercial species in tropical North Queensland, Australia in stress assessment of potential hydrocarbon pollution using ethoxyresorufin O-deethylase (EROD) induction. Our results indicated that barramundi provide a wide range of inducible rates of EROD activity in response to relevant organic stressors. The vegetable- and mineral-based lubricants induced significant EROD activity at 1.0 mg kg -1 and there was no significant difference between the two oil treatments at that concentration. At increasing concentrations of 2 and 3 mg kg -1 , the mineral-based lubricant resulted in slightly higher EROD activity than the vegetable-based lubricant. The EROD activity of control and treated barramundi are found to be within ranges for other species from temperate and tropical environments. These results indicate that vegetable-based lubricants may be less stressful to barramundi than their mineral counterparts at concentrations of lubricant ≥2 mg kg -1 . There is great potential for this species to be used in the biomonitoring of waterways around tropical North Queensland and SE Asia. - Vegetable-based lubricating oils appear to cause a tropical fish species less stress than mineral oils

  4. Testing the ecotoxicology of vegetable versus mineral based lubricating oils: 2. Induction of mixed function oxidase enzymes in barramundi, Lates calcarifer, a tropical fish species

    Energy Technology Data Exchange (ETDEWEB)

    Mercurio, Philip; Burns, Kathryn A.; Cavanagh, Joanne

    2004-05-01

    An increasing number of vegetable-based oils are being developed as environmentally friendly alternatives to petroleum products. However, toxicity towards key tropical marine species has not been investigated. In this study we used laboratory-based biomarker induction experiments to compare the relative stress of a vegetable-based lubricating oil for marine 2-stroke engines with its mineral oil-based counterpart on tropical fish. The sub-lethal stress of 2-stoke outboard lubricating oils towards the fish Lates calcarifer (barramundi) was examined using liver microsomal mixed function oxidase (MFO) induction assays. This study is the first investigation into the use of this key commercial species in tropical North Queensland, Australia in stress assessment of potential hydrocarbon pollution using ethoxyresorufin O-deethylase (EROD) induction. Our results indicated that barramundi provide a wide range of inducible rates of EROD activity in response to relevant organic stressors. The vegetable- and mineral-based lubricants induced significant EROD activity at 1.0 mg kg{sup -1} and there was no significant difference between the two oil treatments at that concentration. At increasing concentrations of 2 and 3 mg kg{sup -1}, the mineral-based lubricant resulted in slightly higher EROD activity than the vegetable-based lubricant. The EROD activity of control and treated barramundi are found to be within ranges for other species from temperate and tropical environments. These results indicate that vegetable-based lubricants may be less stressful to barramundi than their mineral counterparts at concentrations of lubricant {>=}2 mg kg{sup -1}. There is great potential for this species to be used in the biomonitoring of waterways around tropical North Queensland and SE Asia. - Vegetable-based lubricating oils appear to cause a tropical fish species less stress than mineral oils.

  5. Eroding dipoles and vorticity growth for Euler flows in {{{R}}}^{3}: the hairpin geometry as a model for finite-time blowup

    Science.gov (United States)

    Childress, Stephen; Gilbert, Andrew D.

    2018-02-01

    A theory of an eroding ‘hairpin’ vortex dipole structure in three-dimensions is developed, extending our previous study of an axisymmetric eroding dipole without swirl. The axisymmetric toroidal dipole was found to lead to maximal growth of vorticity, as {t}4/3. The hairpin is here similarly proposed as a model to produce large ‘self-stretching’ of vorticity, with the possibility of finite-time blow-up. We derive a system of partial differential equations of ‘generalized’ form, involving contour averaging of a locally two-dimensional Euler flow. We do not attempt here to solve the system exactly, but point out that non-existence of physically acceptable solutions would most probably be a result of the axial flow. Because of the axial flow the vorticity distribution within the dipole eddies is no longer of the simple Sadovskii type (vorticity constant over a cross-section) obtained in the axisymmetric problem. Thus the solution of the system depends upon the existence of a larger class of propagating two-dimensional dipoles. The hairpin model is obtained by formal asymptotic analysis. As in the axisymmetric problem a local transformation to ‘shrinking’ coordinates is introduced, but now in a self-similar form appropriate to the study of a possible finite-time singularity. We discuss some properties of the model, including a study of the helicity and a first step in iterating toward a solution from the Sadovskii structure. We also present examples of two-dimensional propagating dipoles not previously studied, which have a vorticity profile consistent with our model. Although no rigorous results can be given, and analysis of the system is only partial, the formal calculations are consistent with the possibility of a finite time blowup of vorticity at a point of vanishing circulation of the dipole eddies, but depending upon the existence of the necessary two-dimensional propagating dipole. Our results also suggest that conservation of kinetic energy as

  6. Evaluating the influence of feedbacks between erosion rate and weathering on the distribution of erodibility in bedrock river channels

    OpenAIRE

    Shobe, Charles; Hancock, Gregory; Eppes, Martha; Small, Eric

    2018-01-01

    This is a poster presented on November 3rd, 2015 at the Geological Society of America annual meeting in Baltimore, MD, USA. The poster presents rock strength and roughness data from tributaries to the Potomac River in Virginia. Our data support the idea that bedrock channel erodibility is greater on the channel margins than at the thalweg, which we hypothesize to be the result of weathering damage preferentially accumulated on the channel banks. This work was published in Shobe et al (2017; E...

  7. Synergistic Effect of Bone Marrow Transplantation and Bradykinin Potential Factor Isolated from Venom on Thymus and Spleen of Sublethally Irradiated Guinea Pigs

    International Nuclear Information System (INIS)

    Abu-Sinna, G.; Kafafy, Y.; Nassar, A.Y.; Salman, A.

    2005-01-01

    The buthus occitanus, scorpion venom contains a strong bradykinin potentiating factor (BPF) that augments bradykinin effects through enhancing its release. Based on the cytoprotective ability of BPF, the present work investigates it as a radioprotectant. Sublethal whole-body y-irradiation at 1.5 Gy was used. Bone marrow cells suspension (BM cells) alone or in combination with BPF was utilized. Three to four weeks-aged male Guinea pigs were grouped into two major groups. The first was non-irradiated control that was divided into subgroups treated i.p. with BM cells (2.5xl06 cells), one dose of BPF (lug/g b wt), BM cells+ BPF, one week spaced two doses of BPF, BM cells+ 2 doses of BPF, one week spaced three doses of BPF or BM cells+ 3 doses of BPF. Second major group (irradiated group) at 1.5 Gy that, subdivided and treated similarly. 5 animals from each group were killed at 7, 14 and 21 days from the initiation of treatment (3 h after irradiation). The subgroups of non-irradiated animals showed an increase in spleen wt and colony formation, thymus population, and globulins content particularly in those subgroups that stayed for the later time periods (14 and 21 days) and that treated with combined BM cells+ BPF or that groups that were treated with two or three BPF doses. Irradiation caused dramatic destruction in thymus and the spleen reflected on reduction of the lower globulins content. Treatment with BM cells, BM cells+ double doses of BPF or triple doses of BPF caused complete recovery in all measured indices, the best result was observed in those of subgroups treated with BM cells+ double doses of BPF or treated with triple doses of BPF. They completely normalized the investigated parameters after 14 and 21 days respectively

  8. Microbial oxidation of lithospheric organic carbon in rapidly eroding tropical mountain soils.

    Science.gov (United States)

    Hemingway, Jordon D; Hilton, Robert G; Hovius, Niels; Eglinton, Timothy I; Haghipour, Negar; Wacker, Lukas; Chen, Meng-Chiang; Galy, Valier V

    2018-04-13

    Lithospheric organic carbon ("petrogenic"; OC petro ) is oxidized during exhumation and subsequent erosion of mountain ranges. This process is a considerable source of carbon dioxide (CO 2 ) to the atmosphere over geologic time scales, but the mechanisms that govern oxidation rates in mountain landscapes are poorly constrained. We demonstrate that, on average, 67 ± 11% of the OC petro initially present in bedrock exhumed from the tropical, rapidly eroding Central Range of Taiwan is oxidized in soils, leading to CO 2 emissions of 6.1 to 18.6 metric tons of carbon per square kilometer per year. The molecular and isotopic evolution of bulk OC and lipid biomarkers during soil formation reveals that OC petro remineralization is microbially mediated. Rapid oxidation in mountain soils drives CO 2 emission fluxes that increase with erosion rate, thereby counteracting CO 2 drawdown by silicate weathering and biospheric OC burial. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  9. SOIL ERODIBILITY IN THE BRAZILIAN COASTAL PLAINS ERODIBILIDADE DO SOLO NOS TABULEIROS COSTEIROS

    Directory of Open Access Journals (Sweden)

    Nilton Curi

    2011-07-01

    Full Text Available

    In order to determine soil losses caused by water erosion, in different situations, erosion prediction models, such as the Universal Soil Loss Equation (USLE, are used. Their application on agricultural and environmental planning depends on the determination of the USLE factors, including erodibility (K factor. The objective of this study was to determine erodibility for the main soil classes of the Brazilian Coastal Plains region, in Aracruz, Espírito Santo State. The experiment was established in the following soils: medium/clayey texture Yellow Argisol (PA1, Haplic Plinthosol (FX, and moderately rocky Yellow Argisol (PA2. For the calculation of soil erodibility, data of erosivity and soil losses, from November 1997 to May 2004, were used. Soil losses samplings were performed for each rainfall event regarded as erosive. The erodibility values were 0.007 Mg h MJ-1 mm-1

  10. The growth and development of Schistosoma mansoni in mice exposed to sublethal doses of radiation

    International Nuclear Information System (INIS)

    Aitken, R.; Wilson, R.A.

    1989-01-01

    The maturation of Schistosoma mansoni was studied in mice exposed to various sublethal doses of radiation. Although the treatment of mice with 500 rads of radiation prior to infection did not alter parasite maturation, doses in excess of 500 rads led to a reduction in worm burden. This could not be attributed to a delay in the arrival of parasites in the hepatic portal system. Worms developing in mice treated with 800 rads commenced egg-laying about 1 wk later than worms in intact mice, and the rate of egg deposition appeared to be lower in irradiated hosts. The data demonstrate that exposure of C57BL/6 mice to doses of radiation in excess of 500 rads impairs their ability to carry infections of S. mansoni. The findings do not support the hypothesis that primary worm burdens in the mouse are controlled by a host immune response

  11. Larval Red Drum (Sciaenops ocellatus) Sublethal Exposure to Weathered Deepwater Horizon Crude Oil: Developmental and Transcriptomic Consequences.

    Science.gov (United States)

    Xu, Elvis Genbo; Khursigara, Alex J; Magnuson, Jason; Hazard, E Starr; Hardiman, Gary; Esbaugh, Andrew J; Roberts, Aaron P; Schlenk, Daniel

    2017-09-05

    The Deepwater Horizon (DWH) incident resulted in extensive oiling of the pelagic zone and shoreline habitats of many commercially important fish species. Exposure to the water-accommodated fraction (WAF) of oil from the spill causes developmental toxicity through cardiac defects in pelagic fish species. However, few studies have evaluated the effects of the oil on near-shore estuarine fish species such as red drum (Sciaenops ocellatus). Following exposure to a certified weathered slick oil (4.74 μg/L ∑PAH 50 ) from the DWH event, significant sublethal impacts were observed ranging from impaired nervous system development [average 17 and 22% reductions in brain and eye area at 48 h postfertilization (hpf), respectively] to abnormal cardiac morphology (100% incidence at 24, 48, and 72 hpf) in red drum larvae. Consistent with the phenotypic responses, significantly differentially expressed transcripts, enriched gene ontology, and altered functions and canonical pathways predicted adverse outcomes in nervous and cardiovascular systems, with more pronounced changes at later larval stages. Our study demonstrated that the WAF of weathered slick oil of DWH caused morphological abnormalities predicted by a suite of advanced bioinformatic tools in early developing red drum and also provided the basis for a better understanding of molecular mechanisms of crude oil toxicity in fish.

  12. Sublethal injury and virulence changes in Listeria monocytogenes and Listeria innocua treated with antimicrobials carvacrol and citral.

    Science.gov (United States)

    Silva, A; Genovés, S; Martorell, P; Zanini, S F; Rodrigo, D; Martinez, A

    2015-09-01

    The aim of this study was to evaluate the effect of two antimicrobial substances, carvacrol and citral, on Listeria monocytogenes and Listeria innocua cells, as well as possible virulence changes in injured cells, using Caenorhabditis elegans as a model test. The results indicated that the percentage of sublethal damage was higher in L. monocytogenes than in L. innocua. The results of the study carried out by using C. elegans indicated that C. elegans fed in a lawn of L. monocytogenes previously treated with carvacrol showed a loss in life span (p ≤ 0.05) as compared with L. monocytogenes treated with citral, Escherichia coli OP50 as a negative control, and treated and untreated L. innocua. Egg laying was also affected: worms fed in a lawn of treated and untreated L. monocytogenes laid fewer eggs than those fed in a lawn of treated and untreated L. innocua or fed with OP50 as a negative control. Worms fed in a lawn of treated and untreated L. innocua also laid fewer eggs than those fed with OP50 as a negative control. A phenotype named bag of worms and an undescribed new one, "vulva inflammation", were also observed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Acclimation-induced changes in toxicity and induction of metallothionein-like proteins in the fathead minnow following sublethal exposure to cobalt, silver, and zinc

    International Nuclear Information System (INIS)

    Hobson, J.F.

    1986-01-01

    Increases in tolerance and resistance to metal toxicity by aquatic organisms have been linked to elevated levels of low-molecular-weight metal-binding proteins (e.g., metallothioneins). Acclimation-induced changes in toxic response and the concentration of metallothionein-like proteins (MTP) were studied in laboratory populations of the fathead minnow, Pimephales promelas, following sublethal exposure to Co, Ag, and Zn. Following 7 and 14 days of sublethal exposure, tolerance and resistance, as measured by acute toxicity values, were altered in a dose dependent fashion. Acute toxicity values returned to control levels after 21 days of continuous exposure. Tolerance and resistance of Co- and Zn-acclimated animals were depressed after a 7-day post-acclimation period in control water. Tolerance and resistance of Ag-acclimated animals were temporarily enhanced after 7 days post-acclimation and returned to control levels after 14 days. Accumulation of Co, Ag, and Zn measured as wholebody residues appeared to be regulated in 4 of 6 exposure regimes with residues reaching stable levels after 7 to 14 days of exposure. MTP was induced by exposure to 1.8 mg Zn/L and 0.01 mg Ag/L, however, no sustained (i.e., post 21 days) tolerance or resistance were observed at these dose levels indicating that these two biological responses may not be directly related

  14. [Soil anti-erodibility of abandoned lands during different succession stages of plant community in hilly-gullied region of the Loess Plateau: Take Fangta small watershed as an example].

    Science.gov (United States)

    Yan, Fang-chen; Jiao, Ju-ying; Cao, Bin-ting; Yu, Wei-jie; Wei, Yan-hong; Kou, Meng; Hu, Shu

    2016-01-01

    Field survey and laboratory experiment were conducted to study the soil anti-erodibility of abandoned croplands during different vegetation succession stages in hilly-gullied region of the Loess Plateau, based on the analysis of soil particle composition, size distribution and group characteristics, soil aggregate fractal dimensions and stability. The results showed that in the earlier stages of succession from annual to perennial herbs in abandoned croplands, soil size distribution changed a little bit, the fractal dimension of soil particle increased, soil structure improved, fractal dimension and damage percent of soil aggregate structure decreased, soil stability increased, thus soil anti-erodibility increased. Therefore, natural restoration of vegetation is of great significance to improve the soil structure, increase soil erosion resistance, reduce soil erosion and promote sustainable development of regional ecological environment.

  15. Integrated microfluidic technology for sub-lethal and behavioral marine ecotoxicity biotests

    Science.gov (United States)

    Huang, Yushi; Reyes Aldasoro, Constantino Carlos; Persoone, Guido; Wlodkowic, Donald

    2015-06-01

    Changes in behavioral traits exhibited by small aquatic invertebrates are increasingly postulated as ethically acceptable and more sensitive endpoints for detection of water-born ecotoxicity than conventional mortality assays. Despite importance of such behavioral biotests, their implementation is profoundly limited by the lack of appropriate biocompatible automation, integrated optoelectronic sensors, and the associated electronics and analysis algorithms. This work outlines development of a proof-of-concept miniaturized Lab-on-a-Chip (LOC) platform for rapid water toxicity tests based on changes in swimming patterns exhibited by Artemia franciscana (Artoxkit M™) nauplii. In contrast to conventionally performed end-point analysis based on counting numbers of dead/immobile specimens we performed a time-resolved video data analysis to dynamically assess impact of a reference toxicant on swimming pattern of A. franciscana. Our system design combined: (i) innovative microfluidic device keeping free swimming Artemia sp. nauplii under continuous microperfusion as a mean of toxin delivery; (ii) mechatronic interface for user-friendly fluidic actuation of the chip; and (iii) miniaturized video acquisition for movement analysis of test specimens. The system was capable of performing fully programmable time-lapse and video-microscopy of multiple samples for rapid ecotoxicity analysis. It enabled development of a user-friendly and inexpensive test protocol to dynamically detect sub-lethal behavioral end-points such as changes in speed of movement or distance traveled by each animal.

  16. Effects of copper on invertebrate–sediment interactions

    International Nuclear Information System (INIS)

    Hunting, E.R.; Mulder, C.; Kraak, M.H.S.; Breure, A.M.; Admiraal, W.

    2013-01-01

    Toxicants potentially decouple links between biodiversity and ecosystem processes. This study aimed to evaluate how toxicants affect invertebrate bioturbation and decomposition. Effects of copper on functionally distinct macrofaunal species (Asellus aquaticus and Tubifex spp.), decomposition (release of dissolved organic carbon, DOC) and Average Metabolic Response (AMR) and Community Metabolic Diversity (CMD) of bacteria were determined in 5-day microcosm experiments. Bioturbation was assessed as sediment redox potential (Eh) profiles. Concentration–response curves of the functional parameters DOC, and the faunal mediated AMR and CMD in the presence of Tubifex spp. depended on Tubifex spp. survival, i.e. similar EC 50 values for both endpoints. In contrast, functional parameters in the presence of A. aquaticus were more sensitive than survival. Sediment Eh-profiles showed that reduced decomposition was caused by reduced sediment reworking by A. aquaticus at sub-lethal copper concentrations. These observations hint at a decoupling of invertebrate community structure and ecosystem functioning upon stress. -- Highlights: •We compared invertebrate survival and functional responses to copper amendment. •Differential functional responses depending on invertebrate species. •Reduced functional responses with A. aquaticus at sub-lethal copper concentrations. •Sub-lethal copper concentrations reduced the bioturbating activities of A. aquaticus. •Stress decouples invertebrate community structure and ecosystem functioning. -- Sub-lethal copper concentrations reduced the bioturbating activities of A. aquaticus and invertebrate effects on decomposition, bacterial activity and community metabolic diversity

  17. Chronic exposure to sublethal hexavalent chromium affects organ histopathology and serum cortisol profile of a teleost, Channa punctatus (Bloch)

    International Nuclear Information System (INIS)

    Mishra, Ashish K.; Mohanty, Banalata

    2009-01-01

    Effects of chronic exposures (one and two months) to sublethal doses of hexavalent chromium (2 and 4 mg/L potassium dichromate) on organ histopathology and serum cortisol profile were investigated and their overall impact on growth and behavior of a teleost fish, Channa punctatus was elucidated. Histopathological lesions were distinct in the vital organs gill, kidney and liver. The gill lamellae became lifted, fused, and showed oedema. Hyperplasia and hypertrophy of lamellar epithelial cells were distinct with desquamation. Hypertrophy of epithelial cells of renal tubules and reduction in tubular lumens were observed in the trunk kidney. The atrophy of the head kidney interrenal cells and decreased serum cortisol level indicated exhaustion of interrenal activity. Hepatocyte vacuolization and shrinkage, nuclear pyknosis and increase of sinusoidal spaces were observed in the liver. Abnormal behavioral patterns and reduced growth rate were also noticed in the exposed fish. The chronic hexavalent chromium exposure thus by affecting histopathology of gill, kidney (including interrenal tissue) and liver could impair the vital functions of respiration, excretion, metabolic regulation and maintenance of stress homeostasis which in the long-run may pose serious threat to fish health and affect their population.

  18. Chronic exposure to sublethal hexavalent chromium affects organ histopathology and serum cortisol profile of a teleost, Channa punctatus (Bloch)

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Ashish K. [Department of Zoology, University of Allahabad, Allahabad-211002 (India); Mohanty, Banalata, E-mail: drbana_mohanty@rediffmail.com [Department of Zoology, University of Allahabad, Allahabad-211002 (India)

    2009-09-01

    Effects of chronic exposures (one and two months) to sublethal doses of hexavalent chromium (2 and 4 mg/L potassium dichromate) on organ histopathology and serum cortisol profile were investigated and their overall impact on growth and behavior of a teleost fish, Channa punctatus was elucidated. Histopathological lesions were distinct in the vital organs gill, kidney and liver. The gill lamellae became lifted, fused, and showed oedema. Hyperplasia and hypertrophy of lamellar epithelial cells were distinct with desquamation. Hypertrophy of epithelial cells of renal tubules and reduction in tubular lumens were observed in the trunk kidney. The atrophy of the head kidney interrenal cells and decreased serum cortisol level indicated exhaustion of interrenal activity. Hepatocyte vacuolization and shrinkage, nuclear pyknosis and increase of sinusoidal spaces were observed in the liver. Abnormal behavioral patterns and reduced growth rate were also noticed in the exposed fish. The chronic hexavalent chromium exposure thus by affecting histopathology of gill, kidney (including interrenal tissue) and liver could impair the vital functions of respiration, excretion, metabolic regulation and maintenance of stress homeostasis which in the long-run may pose serious threat to fish health and affect their population.

  19. CHUVAS, EROSIVIDADE, ERODIBILIDADE, USO DO SOLO E SUAS RELAÇÕES COM FOCOS EROSIVOS LINEARES NA ALTA BACIA DO RIO ARAGUAIA / Rainfall, erosivity, erodibility, land use and their relationships with erosion sites in the upper Araguaia River Basin

    Directory of Open Access Journals (Sweden)

    Silvando Carlos da Silva

    2007-12-01

    Full Text Available The intensive process of land occupation by farmers in the tropical savanna region of MidwestBrazil during the last three decades has promoted several environment impacts, such as theoccurrence of gully erosion processes as a consequence of intensive deforestation. Just in theUpper Araguaia River Basin, it was identified more than 300 large and medium gully features,which are related with the high natural susceptibility of the sandy soils; high erosivity and erodibility; inadequate land-use; lack of soil conservation practices; and a high annual rainfallindex during the rainy season. The objective of this research was to identify spatial relationshipsbetween rainfall distribution, erosivity, erodibility, land-use, and gully erosion distribution,which may support environmental planning actions related to land use conservation.Quantitative results show a high correlation between gully erosion distribution and higherosivity/erodibility and inadequate land-use.

  20. Assessment of sublethal endpoints after chronic exposure of the nematode Caenorhabditis elegans to palladium, platinum and rhodium.

    Science.gov (United States)

    Schertzinger, Gerhard; Zimmermann, Sonja; Grabner, Daniel; Sures, Bernd

    2017-11-01

    The aim of this study was to investigate chronic effects of the platinum-group elements (PGE) palladium (Pd), platinum (Pt) and rhodium (Rh) on the nematode Caenorhabditis elegans. Aquatic toxicity testing was carried out according to ISO 10872 by determining 96 h EC 50 values for sublethal endpoints, including growth, fertility and reproduction. Single PGE standard solutions were used as metal source. Based on the EC 50 values for Pt, reproduction (96 h EC 50  = 497 μg/L) was the most sensitive endpoint followed by fertility (96 h EC 50  = 726 μg/L) and growth (96 h EC 50  = 808 μg/L). For Pd, no precise EC 50 values could be calculated due to bell-shaped concentration response curves, but the 96 h EC 50 for reproduction ranged between 10 and 100 μg/L. Pd and Pt had effects on all endpoints. With raising element concentrations reproduction was inhibited first. At a certain concentration, fertility was also affected, which in turn had an additional effect on reproduction. Growth inhibition can also lead to a loss of fertility if the worms do not reach an appropriate body size to become fertile. Rhodium showed no inhibition of any endpoint between concentrations of 100 to 10,000 μg Rh/L. The results of this study allow the following order of PGE with respect to decreasing toxicity to C. elegans: Pd > Pt » Rh. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Effects of effluent from electoplating industry on the immune response in the freshwater fish, Cyprinus carpio.

    Science.gov (United States)

    Borgia, V J Florence; Thatheyus, A J; Murugesan, A G; Alexander, S Catherine P; Geetha, I

    2018-08-01

    The present study was designed to assess the effect of sublethal concentrations of electoplating industry effluent (EIE) on the non-specific and specific immune responses in the freshwater fish, Cyprinus carpio. Sublethal concentrations of electroplating industry effluent such as 0.004, 0.007, 0.010 and 0.013% were chosen based on the LC 50 values. Experimental fish were exposed to these sublethal concentrations of EIE for 28 days. After 7, 14, 21 and 28 days of treatment, non-specific immune response by serum lysozyme activity, myeloperoxidase activity and antiprotease activity and specific immune response by antibody response to Aeromonas hydrophila using bacterial agglutination assay and ELISA were assessed. The results showed that chronic exposure of fish to 0.004, 0.007, 0.010 and 0.013% EIE, dose-dependently decreased the non-specific and specific immune responses on all the days tested compared to control fish whereas statistically significant suppressive effects were observed in fish exposed to 0.013% of EIE on all activities tested. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Gulf of Mexico offshore operations monitoring experiment (GOOMEX), phase I : sublethal responses to contaminant exposure - introduction and overview

    International Nuclear Information System (INIS)

    Kennicutt, M.C.; Green, R.H.; Montagna, P.

    1996-01-01

    The Gulf of Mexico Offshore Operations Monitoring Experiment (GOOMEX) is a three-phase study to test and evaluate a range of biological, biochemical, and chemical methodologies to detect and assess chronic sublethal biological impacts in the vicinity of long-duration activities associated with oil and gas exploration and production. A chronic impact is defined as an effect on the biota caused by exposure to the long-term accumulation of chemicals in the environment. The basic program, comprising four field activities over a 2-yr period, was designed to detect nearfield impacts and contaminant gradients extending out from each site. Five test sites were evaluated and three selected as most appropriate for long-term study: MU-A85, MAI-686, and HI-A389. The sampling design included a radial pattern with stations at 30-50, 100, 200, 500, and 3000 m distance and employed a dose-response model to test the hypotheses that biological, chemical, and biochemical variations are due to platform-derived contaminants. Study components included contaminant (trace metals and hydrocarbons) analysis in sediments, pore waters, and biological tissues; assemblage analysis of benthic meiofauna, infauna, and epifauna, assessment of community health based on life history and reproduction studies; and the induction of detoxification responses. (author). 57 refs., 9 tabs., 5 figs

  3. Low-temperature thermal decomposition of dioxin-like compounds in fly ash: combination of chemical analysis with in vitro bioassays (EROD and DR-CALUX).

    Science.gov (United States)

    Behnisch, Peter A; Hosoe, Kazunori; Shiozaki, Ken; Ozaki, Hironori; Nakamura, Kazuo; Sakai, Shin-Ichi

    2002-12-01

    To investigate the dechlorination of fly ash during low-temperature treatment under oxygen-deficient conditions (thermocatalyic treatment or Hagenmaier process), six fly ash samples from six different incineration plants were treated in a laboratory experiment or in the actual plant, either under ideal (400 degrees C, 120 min) or intermediate (300 degrees C, 30 min) conditions. The aim of the present study was to confirm the decrease in the I-TEQ (international toxicity equivalency) of polychlorinated dibenzo-p-dioxins/-furans (PCDD/Fs) and coplanar polychlorinated biphenyls (co-PXBs) and, also for the first time, the decrease in the sum of dioxin-like toxicity (bioassay- or bio-TEQ) of all kinds of other dioxin-like Ah receptor agonists (such as PXDD/Fs, PXBs, PXN, X = Br, F) measured by two state-of-the-art cell-based Ah receptor-dependent bioassays: H4IIE-Ethoxy-Resorufin-o-Deethylase (EROD) and H4IIE-luc/DR-Chemical Activated Luciferase expression (DR-CALUX). The treatment efficiency was calculated on the basis of the reduction in the I-TEQ and bio-TED values. For these fly ash samples, the treatment efficiency, as measured by chemical analysis, was higher than 99%, and 85%-99%, in the case of the bio-TED values, indicating that these Ah receptor binding toxic compounds were sufficiently decomposed. Bio-TEQ values for untreated fly ash samples (n = 6) were on average 1.2 times (range 0.7-1.9), for the H4IIE-EROD assay, and 2.8 times (1.1-4.9), for the DR-CALUX assay, higher than I-TEQ values measured by chemical analyses (sum of PCDD/Fs and co-PCBs). In the case of these fly ash samples treated under ideal conditions and therefore low in contaminants, the bio-TEQ values were on average 1.4 times (range 0.9-1.8), for the H4IIE-EROD assay, and 5.1 times (range 1.2-12), for the DR-CALUX assay, higher than the I-TEQ values.

  4. Investigations on the influence of aminopropyl-aminoethyl-phosphorothioic acid on the radio-iron utilization after a whole-body irradiation of mice in the sublethal dose range

    International Nuclear Information System (INIS)

    Moenig, H.; Seiter, I.; Kofler, E.

    1975-01-01

    The effectiveness of the thiophosphate compound WR 2721 was investigated with regard to the radiosensitivity of X-irradiated female mice in the sublethal dose range of 50 to 150 R using the radioiron test ( 59 Fe). An increase of the radioresistance with regard to the radioiron uptake in young erythrocyte populations was obtained only beyond radiation doses of 75 R. In lower dose ranges the animals treated with thiophoshate became even more radiosensitive. At dose values of 100 R and 150 R dose reduction factors (DRF) of 1.3 and 1.5 respectively were obtained. These factors are considerably smaller than the DRF-values found for the survival rate at LDsub(50/30). A possible mechanism for this result may be due to the different dephosphorylation rate of the thiophosphate in various tissues, as described in literature. (orig.) [de

  5. Cytotoxicity and Hsp 70 induction in Hep G2 cells in response to zearalenone and cytoprotection by sub-lethal heat shock

    International Nuclear Information System (INIS)

    Hassen, Wafa; Golli, Emna El; Baudrimont, Isabelle; Mobio, A. Theophile; Ladjimi, M. Moncef; Creppy, E. Edmond; Bacha, Hassen

    2005-01-01

    Zearalenone (ZEN) is a mycotoxin with several adverse effects in laboratory and domestic animals. The mechanism of ZEN toxicity that involves mainly binding to oestrogen receptors and inhibition of macromolecules synthesis is not fully understood. Using human hepatocytes Hep G2 cells as a model, the aim of this work was (i) to investigate the ability of ZEN to induce heat shock proteins Hsp 70 and (ii) to find out the mechanisms of ZEN cytotoxicity by examining cell proliferation and protein synthesis. Our study demonstrated that ZEN induces Hsp 70 expression in a time and dose-dependant manner; this induction occurs at non-cytotoxic concentrations, it could be therefore considered as a biomarker of toxicity. A cytoprotective effect of Hsp 70 was elicited when Hep G2 cells were exposed to Sub-Lethal heat shock prior to ZEN treatment and evidenced by a reduced ZEN cytolethality. This cytoprotection suggests that Hsp 70 may constitute an important cellular defence mechanism. Finally, our data show that ZEN is cytotoxic in Hep G2 cells by inhibiting cell proliferation and total protein synthesis and pointed out oxidative damage as possible pathway involved in ZEN toxicity; however, other investigations are needed to further confirm Zen induced oxidative stress

  6. Radioprotective effects of flurbiprofen and its nitroderivative

    International Nuclear Information System (INIS)

    Juchelkova, L.; Hofer, M.; Pospisil, M.; Pipalova, I.

    1998-01-01

    Radioprotective effects of two non-steroidal anti-inflammatory drugs, flurbiprofen (FBP) and its novel nitroderivative flurbiprofen 4-nitroxy butylester (NO-FBP), which exhibits decreased gastrointestinal toxicity, were compared in mice. The drugs were administered in equimolar single doses, 2 hours before whole-body gamma irradiation of the animals. After a sublethal radiation dose of 6.5 Gy, significantly increased numbers of endogenous haemopoietic spleen colonies and enhanced granulopoiesis were found in mice given either FBP or NO-FBP, when compared to vehicle-treated controls. There were no differences in the effectiveness of either drug to enhance postirradiation haemopoietic recovery. Survival of FBP- or NO-FBP-treated mice subjected to a lethal dose of 9.5 Gy was slightly but insignificantly enhanced, both drugs showing the same effect. These results clearly indicate the ability of both drugs to enhance haemopoietic recovery after sublethal radiation exposure and the absence of unfavourable effects under higher radiation doses. Because of its lower potential for gastrointestinal damage, NO-FBP seems to be a promising drug which can find a use in the protection of postirradiation myelosuppression. (author)

  7. Colony formation by sublethally heat-injured Zygosaccharomyces rouxii as affected by solutes in the recovery medium and procedure for sterilizing medium.

    Science.gov (United States)

    Golden, D A; Beuchat, L R

    1990-01-01

    Recovery and colony formation by healthy and sublethally heat-injured cells of Zygosaccharomyces rouxii as influenced by the procedure for sterilizing recovery media (YM agar [YMA], wort agar, cornmeal agar, and oatmeal agar) were investigated. Media were supplemented with various concentrations of glucose, sucrose, glycerol, or sorbitol and sterilized by autoclaving (110 degrees C, 15 min) and by repeated treatment with steam (100 degrees C). An increase in sensitivity was observed when heat-injured cells were plated on glucose-supplemented YMA at an aw of 0.880 compared with aws of 0.933 and 0.998. Colonies which developed from unheated and heated cells on YMA at aws of 0.998 and 0.933 generally exceeded 0.5 mm in diameter within 3.5 to 4 days of incubation at 25 degrees C, whereas colonies formed on YMA at an aw of 0.880 typically did not exceed 0.5 mm in diameter until after 5.5 to 6.5 days of incubation. The number of colonies exceeding 0.5 mm in diameter which were formed by heat-injured cells on YMA at an aw of 0.880 was 2 to 3 logs less than the total number of colonies detected, i.e., on YMA at an aw of 0.933 and using no limits of exclusion based on colony diameter. A substantial portion of cells which survived heat treatment were sublethally injured as evidenced by increased sensitivity to a suboptimum aw (0.880). In no instance was recovery of Z. rouxii significantly affected by medium sterilization procedure when glucose or sorbitol was used as the aw-suppressing solute.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2403251

  8. Colony formation by sublethally heat-injured Zygosaccharomyces rouxii as affected by solutes in the recovery medium and procedure for sterilizing medium.

    Science.gov (United States)

    Golden, D A; Beuchat, L R

    1990-08-01

    Recovery and colony formation by healthy and sublethally heat-injured cells of Zygosaccharomyces rouxii as influenced by the procedure for sterilizing recovery media (YM agar [YMA], wort agar, cornmeal agar, and oatmeal agar) were investigated. Media were supplemented with various concentrations of glucose, sucrose, glycerol, or sorbitol and sterilized by autoclaving (110 degrees C, 15 min) and by repeated treatment with steam (100 degrees C). An increase in sensitivity was observed when heat-injured cells were plated on glucose-supplemented YMA at an aw of 0.880 compared with aws of 0.933 and 0.998. Colonies which developed from unheated and heated cells on YMA at aws of 0.998 and 0.933 generally exceeded 0.5 mm in diameter within 3.5 to 4 days of incubation at 25 degrees C, whereas colonies formed on YMA at an aw of 0.880 typically did not exceed 0.5 mm in diameter until after 5.5 to 6.5 days of incubation. The number of colonies exceeding 0.5 mm in diameter which were formed by heat-injured cells on YMA at an aw of 0.880 was 2 to 3 logs less than the total number of colonies detected, i.e., on YMA at an aw of 0.933 and using no limits of exclusion based on colony diameter. A substantial portion of cells which survived heat treatment were sublethally injured as evidenced by increased sensitivity to a suboptimum aw (0.880). In no instance was recovery of Z. rouxii significantly affected by medium sterilization procedure when glucose or sorbitol was used as the aw-suppressing solute.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Wind-Eroded Crater Floors and Intercrater Plains, Terra Sabaea, Mars

    Science.gov (United States)

    Irwin, Rossman P.; Wray, James J.; Mest, Scott C.; Maxwell, Ted A.

    2018-02-01

    Ancient impact craters with wind-eroded layering on their floors provide a record of resurfacing materials and processes on early Mars. In a 54 km Noachian crater in Terra Sabaea (20.2°S, 42.6°E), eolian deflation of a friable, dark-toned layer up to tens of meters thick has exposed more resistant, underlying light-toned material. These layers differ significantly from strata of similar tone described in other regions of Mars. The light-toned material has no apparent internal stratification, and visible/near-infrared spectral analysis suggests that it is rich in feldspar. Its origin is ambiguous, as we cannot confidently reject igneous, pyroclastic, or clastic alternatives. The overlying dark-toned layer is probably a basaltic siltstone or sandstone that was emplaced mostly by wind, although its weak cementation and inverted fluvial paleochannels indicate some modification by water. Negative-relief channels are not found on the crater floor, and fluvial erosion is otherwise weakly expressed in the study area. Small impacts onto this crater's floor have exposed deeper friable materials that appear to contain goethite. Bedrock outcrops on the crater walls are phyllosilicate bearing. The intercrater plains contain remnants of a post-Noachian thin, widespread, likely eolian mantle with an indurated surface. Plains near Hellas-concentric escarpments to the north are more consistent with volcanic resurfacing. A 48 km crater nearby contains similar dark-over-light outcrops but no paleochannels. Our findings indicate that dark-over-light stratigraphy has diverse origins across Mars and that some dark-toned plains with mafic mineralogy are not of igneous origin.

  10. Lethal and sublethal responses to a sediment bound toxicant by two oligochaetes from Lake Michigan: stylodrilus heringianus and limnodrilus hoffmeisteri

    International Nuclear Information System (INIS)

    Keilty, T.J.

    1987-01-01

    Short-term lethal, and short and long-term sublethal responses by Stylodrilus heringianus (Lumbriculidae) and Limnodrilus hoffmeisteri (Tubificidae) to sediments dosed with endrin were measured in single and mixed species tests. Ninety-six hour LC 50 values were 2588 +/- 1974 and 2757 +/- 995 ug/g dry weight sediment for S. heringianus and L. hoffmeisteri respectively. Ninety-six hour EC 50 burrowing avoidance values (concentration where 50% do not burrow) were one to two orders of magnitude lower than the LC 50 's. Short-term mixed species LC 50 data suggested that L. hoffmeisteri may benefit from the presence of S. heringianus. Long-term sublethal responses were quantified by measuring sediment reworking rates (the rate at which subsurface sediments are egested at the surface and re-buried) in laboratory microcosms. Rates were determined by monitoring a gamma-emitting 137 Cesium marker layer with a well-collimated NaI detector. Sediment endrin concentrations ranged from 3 ng/g to 82 ug/g in six 1300 hour experiments. For S. heringianus, reworking rates were stimulated at low concentrations during the first half of experiments, followed by gradual decreases relative to controls. Stimulation of L. hoffmeisteri reworking was not observed. At high concentrations, early reworking rates were reduced for both species, followed by dramatic decreases later on. In mixed species experiments at high concentrations, the presence of S. heringianus enhanced the reworking of L. hoffmeisteri, although the reverse was not observed. Decreased mortality and increased post experimental dry weights of L. hoffmeisteri in mixed, relative to single species tests were also observed. Generally, post experimental worm weights were inversely related to sediment endrin loads, and bioconcentration factors for S. heringianus (10-40) were approximately fourfold that of L. hoffmeisteri (1-10)

  11. Sublethal exposure to commercial formulations of the herbicides dicamba, 2,4-dichlorophenoxyacetic acid, and glyphosate cause changes in antibiotic susceptibility in Escherichia coli and Salmonella enterica serovar Typhimurium.

    Science.gov (United States)

    Kurenbach, Brigitta; Marjoshi, Delphine; Amábile-Cuevas, Carlos F; Ferguson, Gayle C; Godsoe, William; Gibson, Paddy; Heinemann, Jack A

    2015-03-24

    Biocides, such as herbicides, are routinely tested for toxicity but not for sublethal effects on microbes. Many biocides are known to induce an adaptive multiple-antibiotic resistance phenotype. This can be due to either an increase in the expression of efflux pumps, a reduced synthesis of outer membrane porins, or both. Exposures of Escherichia coli and Salmonella enterica serovar Typhimurium to commercial formulations of three herbicides-dicamba (Kamba), 2,4-dichlorophenoxyacetic acid (2,4-D), and glyphosate (Roundup)-were found to induce a changed response to antibiotics. Killing curves in the presence and absence of sublethal herbicide concentrations showed that the directions and the magnitudes of responses varied by herbicide, antibiotic, and species. When induced, MICs of antibiotics of five different classes changed up to 6-fold. In some cases the MIC increased, and in others it decreased. Herbicide concentrations needed to invoke the maximal response were above current food maximum residue levels but within application levels for all herbicides. Compounds that could cause induction had additive effects in combination. The role of soxS, an inducer of the AcrAB efflux pump, was tested in β-galactosidase assays with soxS-lacZ fusion strains of E. coli. Dicamba was a moderate inducer of the sox regulon. Growth assays with Phe-Arg β-naphtylamide (PAβN), an efflux pump inhibitor, confirmed a significant role of efflux in the increased tolerance of E. coli to chloramphenicol in the presence of dicamba and to kanamycin in the presence of glyphosate. Pathways of exposure with relevance to the health of humans, domestic animals, and critical insects are discussed. Increasingly common chemicals used in agriculture, domestic gardens, and public places can induce a multiple-antibiotic resistance phenotype in potential pathogens. The effect occurs upon simultaneous exposure to antibiotics and is faster than the lethal effect of antibiotics. The magnitude of the

  12. Non-target effects of clothianidin on monarch butterflies

    Science.gov (United States)

    Pecenka, Jacob R.; Lundgren, Jonathan G.

    2015-04-01

    Monarch butterflies ( Danaus plexippus) frequently consume milkweed in and near agroecosystems and consequently may be exposed to pesticides like neonicotinoids. We conducted a dose response study to determine lethal and sublethal doses of clothianidin using a 36-h exposure scenario. We then quantified clothianidin levels found in milkweed leaves adjacent to maize fields. Toxicity assays revealed LC10, LC50, and LC90 values of 7.72, 15.63, and 30.70 ppb, respectively. Sublethal effects (larval size) were observed at 1 ppb. Contaminated milkweed plants had an average of 1.14 ± 0.10 ppb clothianidin, with a maximum of 4 ppb in a single plant. This research suggests that clothianidin could function as a stressor to monarch populations.

  13. Evaluation of the WEPP hillslope model on stable and eroding semiarid woodlands

    International Nuclear Information System (INIS)

    Wilcox, B.P.; Simanton, J.R.

    1995-01-01

    In this paper, we evaluate runoff and erosion prediction by the WEPP hillslope model for two pinyon-juniper sites in New Mexico: one has a low erosion rate (stable site) and the other (unstable site) is eroding at very rapid rates (as a result of landuse and climatic perturbations over the last century). Runoff and erosion measurements were made at plot and hillslope scales at both sites. WEPP was evaluated using both rainfall simulation and natural rainfall data. Rainfall simulation was performed on both vegetated and bare plots. Parameter values used were developed from rainfall simulation experiments and site characteristics. In general, runoff and erosion were underpredicted at both sites but to a much larger degree at the unstable site. On the unstable site predictions were much improved when we used hydraulic conductivity (Ke) derived from the bare plot rainfall simulation. Also of importance, at the unstable site we observed a large increase in erosion as scale increased from the plot to the hillslope as a result of a well developed channel network. These results are preliminary, in that only a few storms were evaluated, however, they do suggest some important strategies for predicting the impact of reduced vegetation cover to erosion in semiarid landscapes

  14. Erodibilidade e tensão crítica de cisalhamento em solos de estradas não pavimentadas Erodibility and critical shear stress on unpaved road soils

    Directory of Open Access Journals (Sweden)

    João F. de Oliveira

    2009-12-01

    Full Text Available A falta de um sistema adequado para drenagem de águas pluviais em estradas não pavimentadas é um dos principais fatores que causam a sua degradação e, para que referidos sistemas possam ser adequadamente planejados e dimensionados é necessário o conhecimento de parâmetros de resistência dos solos. Com este trabalho se teve, por objetivo, determinar a erodibilidade e a tensão crítica de cisalhamento para diferentes solos de estradas não pavimentadas. Utilizou-se um simulador de escoamento superficial instalado diretamente nos canais das estradas, sob condição natural e se determinou a perda de solo para diferentes lâminas de escoamento. A erodibilidade e a tensão crítica de cisalhamento foram determinadas por meio do ajuste de curvas relacionando-se a perda de solo em função da tensão cisalhante provocada pelo escoamento. Os resultados alcançados mostraram variações nos valores de erodibilidade e de tensão crítica de cisalhamento das estradas avaliadas. Os valores de erodibilidade encontrados mostraram, quando comparados com valores observados na literatura, elevada suscetibilidade à erosão para as condições de estradas, sendo mais elevados nos solos de textura mais arenosa e siltosa. Os valores de tensão crítica se mostraram bastante próximos aos observados em outros trabalhos.The absence of an adequate drainage system in unpaved roads is one of the main factors for their degradation. For adequate planning knowledge of the resistance parameters of soil is necessary. This study had as its objective the determinatiom of the erodibility and critical shear stress of unpaved road soils. For this work, a runoff simulator was directly installed on road channels, under natural conditions. Different flow depths were applied and the soil loss was measured for each depth. The erodibility and the critical shear stress were determined through adjusted curves relating soil disaggregation and flow shear stress. The results

  15. Toxicity assessment of sodium fluoride in Drosophila melanogaster after chronic sub-lethal exposure.

    Science.gov (United States)

    Dutta, Moumita; Rajak, Prem; Khatun, Salma; Roy, Sumedha

    2017-01-01

    Sodium fluoride (NaF), one of the most frequently used fluoride compound is composed of Na + and F - . Apart from its use in water fluoridation, NaF also acts as a major component for different dental products like toothpastes, gels and mouth rinses etc. The present study was carried out to explore the toxic impact of chronic NaF exposure on a non-target organism, Drosophila melanogaster. The larvae exposed to different concentrations of NaF through food showed a significant increase in HSP70 expression both qualitatively and quantitatively. The altered tail length and tail intensity in Comet assay validate the increased DNA damage in treated larvae. The activity of AChE, oxidative stress marker enzymes, phase I and phase II detoxifying enzymes were found to be significantly inhibited in the treated larvae when compared to control though there was no evidence of dose dependent change in each case. The alterations in the mentioned parameters can be due to increased body Fluoride ion (F - ) concentration since the analysis with ion electrode analyzer revealed that F - concentration increased significantly with NaF treatment. Hence, the results suggest that D. melanogaster manifest prominent toxic response when subjected to chronic exposure to sub-lethal NaF concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Induced tolerance from a sublethal insecticide leads to cross-tolerance to other insecticides.

    Science.gov (United States)

    Hua, Jessica; Jones, Devin K; Relyea, Rick A

    2014-04-01

    As global pesticide use increases, the ability to rapidly respond to pesticides by increasing tolerance has important implications for the persistence of nontarget organisms. A recent study of larval amphibians discovered that increased tolerance can be induced by an early exposure to low concentrations of a pesticide. Since natural systems are often exposed to a variety of pesticides that vary in mode of action, we need to know whether the induction of increased tolerance to one pesticide confers increased tolerance to other pesticides. Using larval wood frogs (Lithobates sylvaticus), we investigated whether induction of increased tolerance to the insecticide carbaryl (AChE-inhibitor) can induce increased tolerance to other insecticides that have the same mode of action (chlorpyrifos, malathion) or a different mode of action (Na(+)channel-interfering insecticides; permethrin, cypermethrin). We found that embryonic exposure to sublethal concentrations of carbaryl induced higher tolerance to carbaryl and increased cross-tolerance to malathion and cypermethrin but not to chlorpyrifos or permethrin. In one case, the embryonic exposure to carbaryl induced tolerance in a nonlinear pattern (hormesis). These results demonstrate that that the newly discovered phenomenon of induced tolerance also provides induced cross-tolerance that is not restricted to pesticides with the same mode of action.

  17. Effects of salinity on short-term waterborne zinc uptake, accumulation and sub-lethal toxicity in the green shore crab (Carcinus maenas)

    International Nuclear Information System (INIS)

    Niyogi, Som; Blewett, Tamzin A.; Gallagher, Trevor; Fehsenfeld, Sandra; Wood, Chris M.

    2016-01-01

    Highlights: • Zinc accumulation in the euryhaline green crab is partially salinity dependent. • Zinc accumulates mainly in the gills of green crab during acute waterborne exposure. • Branchial zinc and calcium transport in the green crab occurs via a common pathway. • Acute waterborne Zn exposure disrupts calcium and zinc homeostasis in the green crab. - Abstract: Waterborne zinc (Zn) is known to cause toxicity to freshwater animals primarily by disrupting calcium (Ca) homeostasis during acute exposure, but its effects in marine and estuarine animals are not well characterized. The present study investigated the effects of salinity on short-term Zn accumulation and sub-lethal toxicity in the euryhaline green shore crab, Carcinus maenas. The kinetic and pharmacological properties of short-term branchial Zn uptake were also examined. Green crabs (n = 10) were exposed to control (no added Zn) and 50 μM (3.25 mg L"−"1) of waterborne Zn (∼25% of 96 h LC_5_0 in 100 seawater) for 96 h at 3 different salinity regimes (100%, 60% and 20% seawater). Exposure to waterborne Zn increased tissue-specific Zn accumulation across different salinities. However, the maximum accumulation occurred in 20% seawater and no difference was recorded between 60% and 100% seawater. Gills appeared to be the primary site of Zn accumulation, since the accumulation was significantly higher in the gills relative to the hepatopancreas, haemolymph and muscle. Waterborne Zn exposure induced a slight increase in haemolymph osmolality and chloride levels irrespective of salinity. In contrast, Zn exposure elicited marked increases in both haemolymph and gill Ca levels, and these changes were more pronounced in 20% seawater relative to that in 60% or 100% seawater. An in vitro gill perfusion technique was used to examine the characteristics of short-term (1–4 h) branchial Zn uptake over an exposure concentration range of 3–12 μM (200–800 μg L"−"1). The rate of short-term branchial Zn

  18. Effects of salinity on short-term waterborne zinc uptake, accumulation and sub-lethal toxicity in the green shore crab (Carcinus maenas)

    Energy Technology Data Exchange (ETDEWEB)

    Niyogi, Som, E-mail: som.niyogi@usask.ca [Department of Biology, University of Saskatchewan, Saskatoon, SK (Canada); Toxicology Centre, University of Saskatchewan, Saskatoon, SK (Canada); Bamfield Marine Sciences Centre, Bamfield, BC (Canada); Blewett, Tamzin A. [Bamfield Marine Sciences Centre, Bamfield, BC (Canada); Department of Biological Sciences, University of Alberta, Edmonton, AB (Canada); Department of Biology, McMaster University, Hamilton, ON (Canada); Gallagher, Trevor [Toxicology Centre, University of Saskatchewan, Saskatoon, SK (Canada); Fehsenfeld, Sandra [Bamfield Marine Sciences Centre, Bamfield, BC (Canada); Department of Biological Sciences, University of Manitoba, Winnipeg, MB (Canada); Department of Zoology, University of British Columbia, Vancouver, BC (Canada); Wood, Chris M. [Bamfield Marine Sciences Centre, Bamfield, BC (Canada); Department of Biology, McMaster University, Hamilton, ON (Canada); Department of Zoology, University of British Columbia, Vancouver, BC (Canada)

    2016-09-15

    Highlights: • Zinc accumulation in the euryhaline green crab is partially salinity dependent. • Zinc accumulates mainly in the gills of green crab during acute waterborne exposure. • Branchial zinc and calcium transport in the green crab occurs via a common pathway. • Acute waterborne Zn exposure disrupts calcium and zinc homeostasis in the green crab. - Abstract: Waterborne zinc (Zn) is known to cause toxicity to freshwater animals primarily by disrupting calcium (Ca) homeostasis during acute exposure, but its effects in marine and estuarine animals are not well characterized. The present study investigated the effects of salinity on short-term Zn accumulation and sub-lethal toxicity in the euryhaline green shore crab, Carcinus maenas. The kinetic and pharmacological properties of short-term branchial Zn uptake were also examined. Green crabs (n = 10) were exposed to control (no added Zn) and 50 μM (3.25 mg L{sup −1}) of waterborne Zn (∼25% of 96 h LC{sub 50} in 100 seawater) for 96 h at 3 different salinity regimes (100%, 60% and 20% seawater). Exposure to waterborne Zn increased tissue-specific Zn accumulation across different salinities. However, the maximum accumulation occurred in 20% seawater and no difference was recorded between 60% and 100% seawater. Gills appeared to be the primary site of Zn accumulation, since the accumulation was significantly higher in the gills relative to the hepatopancreas, haemolymph and muscle. Waterborne Zn exposure induced a slight increase in haemolymph osmolality and chloride levels irrespective of salinity. In contrast, Zn exposure elicited marked increases in both haemolymph and gill Ca levels, and these changes were more pronounced in 20% seawater relative to that in 60% or 100% seawater. An in vitro gill perfusion technique was used to examine the characteristics of short-term (1–4 h) branchial Zn uptake over an exposure concentration range of 3–12 μM (200–800 μg L{sup −1}). The rate of short

  19. Haematological changes in Bufo maculatus treated with sublethal concentrations of Cadmium

    Directory of Open Access Journals (Sweden)

    Lawrence Ikechukwu Ezemonye

    2011-12-01

    Full Text Available Adult Bufo maculatus was exposed to sublethal cadmium concentrations of 0.25, 0.50, 1.00 and 2.00 mg/L. The toxicant from which the cadmium concentrations were prepared was cadmium chloride (CdCl2.H2O. There were three replicate tanks per treatment and three individuals per tank including control groups. The hematologic alterations based on the examination of blood indices during the 28 days of exposure showed that total erythrocyte count (TEC, hematocrit (Hct and hemoglobin (Hb concentration decreased (P<0.05 relative to controls. The decline was concentration- dependent as concentration of cadmium increased. The decline in hemoglobin and hematocrit in the experimental organism could be due to a decrease in the synthesis or release of erythrocytes into the circulation or an increase in the rate of erythrocyte destruction inflicted by cadmium toxicity. There was significant (P<0.05 elevation in total leuko- leukocyte count (TLC with increase in the concen- cyte concentration of cadmium. The increase in total leukocyte count observed in this study could be attributed to a stimulation of the immune system in response to tissue damage caused by cadmium toxicity. The study has shown that the exposure of the Bufo maculatus toad to cadmium can inflict alterations in the hematologic indices, which could induce unfavorable physiological changes in the amphibian, which may lead to death. There is, therefore, the need to protect amphibians in order to sustain the biodiversity in the Nigerian Niger Delta ecological zone.

  20. Stronger effects of Roundup than its active ingredient glyphosate in damselfly larvae.

    Science.gov (United States)

    Janssens, Lizanne; Stoks, Robby

    2017-12-01

    Pesticides are causing strong decreases in aquatic biodiversity at concentrations assumed safe by legislation. One reason for the failing risk assessment may be strong differences in the toxicity of the active ingredient of pesticides and their commercial formulations. Sublethal effects, especially those on behaviour, have been largely ignored in this context, yet can be equally important as lethal effects at the population and ecosystem levels. Here, we compared the toxicity of the herbicide Roundup and its active ingredient glyphosate on survival, but also on ecologically relevant sublethal traits (life history, behaviour and physiology) in damselfly larvae. Roundup was more toxic than glyphosate with negative effects on survival, behaviour and most of the physiological traits being present at lower concentrations (food intake, escape swimming speed) or even only present (survival, sugar and total energy content and muscle mass) following Roundup exposure. This confirms the toxicity of the surfactant POEA. Notably, also glyphosate was not harmless: a realistic concentration of 2mg/l resulted in reduced growth rate, escape swimming speed and fat content. Our results therefore indicate that the toxicity of Roundup cannot be fully attributed to its surfactant, thereby suggesting that also the new generation of glyphosate-based herbicides with other mixtures of surfactants likely will have adverse effects on non-target aquatic organisms. Ecotoxicological studies comparing the toxicity of active ingredients and their commercial formulations typically ignore behaviour while the here observed differential effects on behaviour likely will negatively impact damselfly populations. Our data highlight that risk assessment of pesticides ignoring sublethal effects may contribute to the negative effects of pesticides on aquatic biodiversity. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Sublethal Concentrations of Antibiotics Cause Shift to Anaerobic Metabolism in Listeria monocytogenes and Induce Phenotypes Linked to Antibiotic Tolerance

    DEFF Research Database (Denmark)

    Knudsen, Gitte Maegaard; Fromberg, Arvid; Ng, Yin

    2016-01-01

    The human pathogenic bacterium Listeria monocytogenes is exposed to antibiotics both during clinical treatment and in its saprophytic lifestyle. As one of the keys to successful treatment is continued antibiotic sensitivity, the purpose of this study was to determine if exposure to sublethal...... antibiotic concentrations would affect the bacterial physiology and induce antibiotic tolerance. Transcriptomic analyses demonstrated that each of the four antibiotics tested caused an antibiotic-specific gene expression pattern related to mode-of-action of the particular antibiotic. All four antibiotics...... in Imo1179 (eutE) encoding an aldehyde oxidoreductase where rerouting caused increased ethanol production was tolerant to three of four antibiotics tested. This shift in metabolism could be a survival strategy in response to antibiotics to avoid generation of ROS production from respiration by oxidation...

  2. Effects of antibiotic decontamination of the GI tract and pretreatment with sublethal doses of endotoxins on survival after whole-liver irradiation and 2/3 partial hepatectomy (PH)

    International Nuclear Information System (INIS)

    Geraci, J.P.; Jackson, K.L.; Mariano, M.S.; Leitch, J.M.

    1984-01-01

    Thirty-two rats were preconditioned by I.P. injection of sublethal doses of E. Coli endotoxin two weeks before irradiation. Thirty-two other animals were sham injected with endotoxin free water. One week before irradiation half of the endotoxin treated animals and half the sham-injected animals received non-absorbable antibiotics in their drinking water to decontaminate the intestinal tract. All 64 animals were exposed to 30 Gy whole-liver gamma-irradiation after surgically exposing the liver and moving the G.I. tract, spleen, and stomach out of the radiation field. Immediately after irradiation a 2/3 PH was performed. The animals were checked daily for 100 days postirradiation. Median survival times for sham-treated, decontaminated, endotoxin-treated, and endotoxin-treated + decontaminated animals were, respectively, 16, 26, 38, and 85 days. All animals died within 100 days except in the group receiving both endotoxin and antibiotic treatments. One third of these animals are still alive 100 days after irradiation. The significance of these results with respect to mechanisms of hepatic radiation injury are discussed

  3. Effect of granulocyte colony-stimulating factor on murine thymic emigration and subsets reconstitution after a sublethal dose of irradiation

    International Nuclear Information System (INIS)

    Zhao Hongxia; Guo Mei; Sun Xuedong; Ai Huisheng

    2011-01-01

    Objective: To investigate the effects of recombinant human granulocyte colony stimulating factor (G-CSF) on murine thymic emigration and subsets reconstitution after a sublethal dose of irradiation. Methods: Female BALB/c mice were irradiated with a 6.0 Gy of γ-ray total-body irradiation and then randomly divided into GCSF group and control group. For mice in the GCSF group, recombinant human G-CSF 100 μg · kg -1 · d -1 was injected subcutaneously once daily for 14 continuous days and mice in the control group were given the same volume of phosphate buffered solution (PBS). At 7, 14, 21 and 28 days later, mice were killed and thymus mononuclear cell suspension were analyzed by flow cytometry for the percentage of the four stages of thymic CD4 - CD8 - double negative cells (DN1-4) and the CD4 + CD8 + double positive ( CD4 + CD8 + DP), CD4 + CD8 - single positive (CD4 + SP), CD4 - CD8 + single positive cells (CD8 + SP).Real-time PCR was used for detection and quantitation of murine T cell receptor rearrangement excision circles (sjTRECs) of the thymic cells of 30 and 60 d after irradiation. Results: The percentage of thymic DN1 cells in GCSF group was significantly higher than that of the control group 7 d after irradiation (t=9.59, P<0.05). 21 d later, the proportion of thymic DN3 and DN4 cells were higher than those of the control group (t=16.37, 7.6, P<0.05). The percentage of thymic CD4 + CD8 + DP cells decreased 7 d after irradiation,increased at 14 d, decreased again at 21 days,and then got a permanent recover. The percentage of thymic CD4 + CD8 + DP cells in the GCSF group recovered to normal and was significantly higher than that of the control group 28 days after irradiation (t=12.22, P<0.05). The percentage of thymic CD8 + SP cells of the GCSF group was significantly higher than that of the control group 21 d after irradiation (t=3.77, P<0.05), while G-CSF had no obvious influence on the percentage of the thymic CD4 + SP cells. The sjTRECs copies in the

  4. Effects of enamel abrasion, salivary pellicle, and measurement angle on the optical assessment of dental erosion

    Science.gov (United States)

    Lussi, Adrian; Bossen, Anke; Höschele, Christoph; Beyeler, Barbara; Megert, Brigitte; Meier, Christoph; Rakhmatullina, Ekaterina

    2012-09-01

    The present study assessed the effects of abrasion, salivary proteins, and measurement angle on the quantification of early dental erosion by the analysis of reflection intensities from enamel. Enamel from 184 caries-free human molars was used for in vitro erosion in citric acid (pH 3.6). Abrasion of the eroded enamel resulted in a 6% to 14% increase in the specular reflection intensity compared to only eroded enamel, and the reflection increase depended on the erosion degree. Nevertheless, monitoring of early erosion by reflection analysis was possible even in the abraded eroded teeth. The presence of the salivary pellicle induced up to 22% higher reflection intensities due to the smoothing of the eroded enamel by the adhered proteins. However, this measurement artifact could be significantly minimized (pmeasurement angles from 45 to 60 deg did not improve the sensitivity of the analysis at late erosion stages. The applicability of the method for monitoring the remineralization of eroded enamel remained unclear in a demineralization/remineralization cycling model of early dental erosion in vitro.

  5. Effects of sub-lethal levels of dichlorodiphenyltrichloroethane and dichlorodiphenyldichloroethylene on in vitro steroid biosynthesis by ovarian follicles or steroid metabolism by embryos of rainbow trout (Oncorhynchus mykiss)

    International Nuclear Information System (INIS)

    Petkam, Rakpong; Renaud, Rick; Lin, Lucy; Boermans, Herman; Leatherland, John

    2005-01-01

    This study examined the possibility that DDT and DDE, at sub-lethal exposure levels, exert direct effects on the biotransformation of gonadal steroids by rainbow trout (Oncorhynchus mykiss) ovarian follicles and embryos. Ovarian follicles were co-incubated with DDT or DDE at 0.01 or 1 mg l -1 to examine effects of the pesticides on basal or cAMP-activated steroidogenesis. Ovarian preparations were incubated with radiolabelled [ 3 H]pregnenolone ([ 3 H]P 5 ), and the tritiated metabolites of [ 3 H]P 5 metabolism were separated using high-performance liquid chromatography (HPLC). Testosterone (T) and 17β-estradiol (E 2 ) production were also measured using radioimmunoassay (RIA). Embryos were either exposed to the pesticides in ovo, or co-incubated in vitro with the pesticides. The effect of the pesticides on embryo steroid biotransformation was examined using a range of radioactively labelled substrates, including [ 3 H]P 5 , [ 3 H]progesterone ([ 3 H]P 4 ), [ 3 H]T and [ 3 H]E 2 . At the concentrations used, the pesticides had no significant effect on the relative amounts of unconjugated radiolabelled steroids formed by the biotransformation of [ 3 H]P 5 under conditions of basal or cAMP-stimulated ovarian steroidogenesis. However, DDT and DDE appeared to reduce the basal accumulation of androgen as a product of P 5 biotransformation by ovarian follicles. Basal or cAMP-stimulated total estrogen production was not affected. In addition, DDT at 1 mg l -1 and DDE at 0.01 mg l -1 significantly increased and decreased cAMP-stimulated T accumulation, respectively. Also DDT at 0.01 mg l -1 and DDE at 1 mg l -1 significantly increased and decreased basal E 2 accumulation, respectively. The steroid metabolites synthesized from the different substrates by embryos were essentially similar in both controls and pesticide-exposed groups, and the survival of embryos to hatch was not significantly affected by pesticide exposure, in ovo, with an approximately 90% hatchability in

  6. The concentrations of heavy metals and the incidence of micronucleated erythrocytes and liver EROD activity in two edible-fish from the Paraíba do Sul river basin in Brazil | Concentração de metais pesados e incidência de eritrócitos micronucleados e atividade de EROD hepática em duas espécies de peixes comestíveis na bacia do Rio Paraíba do Sul, Brasil

    Directory of Open Access Journals (Sweden)

    Thiago Estevam Martins Parente

    2015-02-01

    Full Text Available The Paraíba do Sul river (PSR basin crosses one of the most populated and industrialized regions of Brazil and receives effluent from the metallurgic, paper mill and agricultural industries. PSR water has multiple uses, including being a supply of potable water and riverine populations which consume some species of its fish. In the present study, we investigated the responses of two biomarkers of aquatic pollution, EROD activity in the liver and micronuclei frequency in peripheral blood, as well as the concentrations of seven heavy metals in the muscle tissue of two species of fish native to the PSR: Geophagus brasiliensis and Hypostomus sp. Sampling was performed in both the wet and dry seasons of 2003, with a total of 339 fish collected from 16 sites along the PSR basin. Fish collected at Levy Gasparian, Barra Mansa and Três Rios both had higher EROD activity and micronuclei frequency. The results also suggested a moderate induction of EROD activity in fish collected from S.L. Paraitinga and Sapucaia. Micronuclei frequency was elevated in fish from S.J. Campos, Além Paraíba, Campos and S.J. Barra. In all cases, heavy metal concentrations did not exceed the maximum considered safe for fish meat consumption. -------------------------------------------------------------------------------------------- A bacia do rio Paraíba do Sul (PSR atravessa uma das regiões mais povoadas e industrializadas do Brasil, recebendo efluentes de indústrias metalúrgicas, de papel e celulose e agrícolas. Os usos das águas do PSR são múltiplos, incluem o fornecimento de água potável, e as populações ribeirinhas consomem algumas de suas espécies de peixes. No presente trabalho foram investigadas as respostas de dois biomarcadores à poluição, a atividade hepática de EROD e a freqüência de micronúcleo em sangue periférico, e medidos os níveis de sete metais pesados no músculo de duas espécies de peixes nativas do PSR, Geophagus brasiliensis and

  7. Recovery of immune competence following sublethal irradiation: the role of the mouse strains, thymic function and aging

    International Nuclear Information System (INIS)

    Peterson, W.J.

    1976-01-01

    The bone marrow, thymus and lymphohematopoietic microenvironments are determining factors in recovery of immune competence following sublethal irradiation. Because of age-related degenerative changes in all of these parameters it was anticipated that immune competence of irradiated old mice would show an altered pattern of recovery. Therefore, three age groups (3-7, 15, and 23-34-months) of C57BL/6J mice were treated with either 250R, 500R or 600R. At various intervals thereafter their spleen cells were assessed for recovery of humoral and cell-mediated immunologic activity and for thymus derived (T-), bone marrow derived (B-) and stem-cell compartments. Two age groups (3-7 and 23-months) of C3H/Anf Cum mice were also treated with the two highest doses or irradiation and their spleen cells tested only for recovery of T- and B-cell compartments. The results showed that recovery of immune competence following 250R was independent of age

  8. Aplicación del bioensayo EROD-H4IIE para la determinación de dioxinas en carnes de pollos broiler: un estudio de equivalencia con la cromatografía de gases de alta resolución acoplada a espectrometría de masas de alta resolución Application of the EROD-H4IIE bioassay for the determination of dioxins in broiler chicken meat: an equivalence study with high resolution gas chromatography coupled to high resolution mass spectrometry

    OpenAIRE

    JT Schoffer; C Bustos-López; P Sotomayor; CA Mattar; A González; C Robles; F Samsing; O Acevedo; CE Valdovinos

    2011-01-01

    En el presente estudio se aplicó el bioensayo EROD con línea celular H4IIE para determinar la equivalencia de resultados para carnes de pollo, entre el bioensayo EROD-H4IIE en pg TCDD-EQ/g de tejido y los resultados de la cromatografía de gases de alta resolución acoplada a espectrometría de alta resolución (HRGC/HRMS) en pg WHO-TEQ/g de grasa. Para lo anterior se utilizaron 41 muestras compuestas de trutros de pollo. Éstas fueron obtenidas en la planta faenadora de 4 planteles diferentes de ...

  9. Modeling response of species to microcontaminants: comparative ecotoxicology by (sub)lethal body burdens as a function of species size and partition ratio of chemicals.

    Science.gov (United States)

    Hendriks, A J

    1995-11-01

    A model was designed and calibrated with accumulation data to calculate the internal concentrations of microcontaminants in organisms as a function of a few constants and variables. The main factors are the exposure time, the external exposure concentration, the partition ratio of the compound, and the size of the taxon concerned. The model was applied to calculate the lethal and sublethal body burdens of several priority compounds and some major taxa. Estimations were generally confirmed at the order of magnitude level by measured residues and applied doses if available. According to the estimations, most priority compounds chosen were critical for most taxa above internal concentrations of 0.1 mmol.kg-1 wet wt. Trichloromethane, 1,2,4-trichlorobenzene, and hexachlorobenzene were lethal above this level only, whereas other organic microcontaminants affected at least some taxa at lower body burdens. The log(Kow) of the organic compounds ranged from 2.0 to 7.0. Keeping in mind that bioconcentration and -magnification ratios for metals may be quite variable, the lowest critical residues estimated were just below the value of 0.1 mmol.kg-1 wet wt. Here, external concentrations encountered in natural habitats seem to be a promising tool for predictive comparative ecotoxicology. The critical body burdens for plants and invertebrates may have been overestimated due to uncertainty about the parameters. Among the different taxa, however, the fish families chosen (Salmonidae and Cyprinidae) seem to be most sensitive to most compounds. Internal response concentrations of the herbicide atrazine were the lowest in micro- and macrophytes, whereas parathion affected invertebrates at low levels. The database that provided the external response concentrations was also consulted to estimate so-called extrapolation or safety factors. On average, long-term no effect concentrations in water are estimated to be about 10-30 times below short-term median lethal levels. In general, short

  10. Supporting data for comparative proteomic analysis of Listeria monocytogenes ATCC 7644 exposed to a sublethal concentration of nisin

    Directory of Open Access Journals (Sweden)

    Kendi Nishino Miyamoto

    2015-06-01

    Full Text Available Here we provide the LC–MS/MS data from a comparative analysis of Listeria monocytogenes ATCC 7644 treated and non-treated with a sublethal concentration of nisin (10−3 mg/mL. Protein samples were analyzed by multidimensional protein identification technology (MudPIT approach, in an off-line configuration. The raw MS/MS data allowed the detection of 49,591 spectra which resulted in 576 protein identifications. After Scaffold validation, 179 proteins were identified with high confidence. A label-free quantitative analysis based of normalized spectral abundance factor (NSAF was used and 13 proteins were found differentially expressed between nisin-treated and non-treated cells. Gene ontology analysis of differentially expressed proteins revealed that most of them are correlated to metabolic process, oxidative stress response mechanisms and molecular binding. A detailed analysis and discussion of these data may be found in Miyamoto et al. [1].

  11. Gulf of Mexico offshore operations monitoring experiment (GOOMEX), Phase I: Sublethal responses to contaminant exposure - introduction and overview

    International Nuclear Information System (INIS)

    Kennicutt, M. C.; Montagna, P.; Roscigno, P. F.

    1996-01-01

    An overview of a three-phase study to evaluate the range of biological, biochemical and chemical methodologies to detect and assess chronic sublethal biological impacts in the vicinity of long-duration activities in the Gulf of Mexico associated with oil and gas exploration and production, was provided. The basic program comprises four activities stretching over a two-year period, and is designed to detect nearfield impacts and contaminant gradients extending out of each of three sites. Sampling design includes a radial pattern with stations at intervals up to 3000 meters distant from the platform. The design employs a dose-response model to test the hypothesis that biological, biochemical and chemical variations are due to platform-derived contaminants. Detailed analysis of the contaminants includes analysis of sediments, pore waters and biological tissue, and assessment of community health based on life history and reproduction studies. 57 refs., 9 tabs., 5 figs

  12. Effect of single and binary combinations of plant-derived molluscicides on reproduction and survival of the snail Achatina fulica.

    Science.gov (United States)

    Rao, I G; Singh, D K

    2000-11-01

    The effects of sublethal treatments (20% and 60% of LC(50)/24 h) with plant-derived molluscicides on the reproduction of the giant African snail Achatina fulica were studied. Azadirachta indica oil, Cedrus deodara oil, Allium sativum bulb powder, and Nerium indicum bark powder singly and binary combinations on reproduction and survival of A. fulica were investigated. Repeated treatment occurred on day 0, day 15, and day 30. These plant-derived molluscicides significantly reduced fecundity, egg viability, and survival of A. fulica within 15 days. Discontinuation of the treatments after day 30 did not lead to a recovery trend in the next 30 days. Day 0 sublethal treatment of all the molluscicides caused a maximum reduction in protein, amino acid, DNA, RNA, and phospholipid levels and simultaneous increase in lipid peroxidation in the ovotestis of treated A. fulica. It is believed that sublethal exposure of these molluscicides on snail reproduction is a complex process, involving more than one factor in reducing the reproductive capacity of A. fulica.

  13. Sublethal haematological effects of zinc on the freshwater fish ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-06-17

    Jun 17, 2008 ... were taken from the control and experimental fish. ... differential white blood cell counts were decreased except for the lymphocytes in which ... this indicates a depressive effect on tissue respiration ..... the reduction in cellular blood iron, resulting in reduced ... Changes in carbohydrate metabolism occur in.

  14. Importance of dose metrics for lethal and sublethal sediment metal toxicity in the oligochaete worm Lumbriculus variegatus

    Energy Technology Data Exchange (ETDEWEB)

    Penttinen, O.P.; Kilpi-Koski, J.; Toivainen, K. [Helsinki Univ., Lahti (Finland). Dept. of Ecology end Environmental Sciences; Jokela, M. [Mikkeli Univ. of Applied Sciences, Mikkeli (Finland); Vaeisaenen, A. [Jyvaeskylae Univ. (Finland). Dept. of Chemistry

    2008-02-15

    Background, aims, and scope. There is an increasing demand for controlled toxicity tests to predict biological effects related to sediment metal contamination. In this context, questions of metal-specific factors, sensitivity of toxicity endpoints, and variability in exposure duration arise. In addition, the choice of the dose metrics for responses is equally important and is related to the applicability of the concept of critical body residue (CBR) in exposure assessments, as well as being the main focus of this study. Methods. Experiments were conducted to assess toxicity of Cd, Cr, Cu and Pb to the oligochaete worm Lumbriculus variegatus with the aim of determining CBRs for two response metrics. Mortality and feeding activity of worms exposed to sediment-spiked metals were used as end-points in connection with residue analyses from both the organisms and the surrounding media. Results. LC50 values were 0.3, 1.4, 5.2, and 6.7 mg/L (from 4.7 {mu}mol/L to 128.0 {mu}mol/L), and the order of toxicity, from most toxic to least toxic, was Cu > Cd > Pb>Cr. By relating toxicity to body residue, variability in toxicity among the metals decreased and the order of toxicity was altered. The highest lethal residue value was obtained for Cu (10.8 mmol/kg) and the lowest was obtained for Cd (2.3 mmol/kg). In the 10-d sublethal test, both time and metal exposure were an important source of variation in the feeding activity of worms. The significant treatment effects were observed from worms exposed to Cd or Pb, with the controls yielding the highest feeding rate. However, quantitative changes in the measured end-point did not correlate with the exposure concentrations or body residues, which remained an order of magnitude lower than in the acute exposures. (orig.)

  15. Social perception of soil conservation benefits in Kondoa eroded area of Tanzania

    Directory of Open Access Journals (Sweden)

    Rajendra P. Shrestha

    2015-09-01

    Full Text Available A soil conservation project was implemented in Tanzania for over 30 years. This study applied a socio-economic approach to examine and analyse the benefits of soil conservation in the Kondoa eroded area of Tanzania by conducting a household survey of 240 households. The study findings show that 89% and 70% of respondents consider soil conservation activities have increased vegetation and soil fertility, respectively. Decreased soil erosion was perceived by 68% of respondents, increased firewood by 98%, increased fodder by 50%, high crop yields by 56%, and food sufficiency by 68%. These are the outcomes of conservation tillage, integrated farming and use of organic fertilizers, controlled stall feeding, agroforestry, construction of cut off drains, contour bunds and contour ridges cultivation, which are the main land use practices in the area. Access to extension services, household sizes, long term land ownership, crop incomes and awareness of soil conservation project were found to determine the level of participation in soil conservation. Major challenges are the lack of sustainability of those activities because of a recent policy decision to withdraw conservation investment. Despite the challenge, this study concluded that past government efforts on soil conservation activities initiated since the early 1970s through decentralization, institutional collaboration, socioeconomic support to farmers and continuous local community participation in restoring the degraded ecosystem of Kondoa have contributed to ensure environmental and socio-economic sustainability in the area.

  16. Effects of Pyriproxyfen on Life Table Indices of Plutella xylostella in Multigenerations

    Directory of Open Access Journals (Sweden)

    Mohammad Mahmoudvand

    2015-01-01

    Full Text Available The diamondback moth (DBM, Plutella xylostella (L. (Lepidoptera: Plutellidae, is a major pest of Brassicaceae family in Iran. This study investigated the sublethal effects of pyriproxyfen, a juvenile hormone analogue, on DBM, for two subsequent generations. The leaf dip bioassay method was adopted in conducting this experiment. Sublethal concentrations resulted in a significant decrease in fecundity, oviposition period, and pupal weight of parents and offspring generations. Also, the development time of DBM was prolonged after exposure to pyriproxyfen. The biological parameters such as net reproductive rate (R0 and intrinsic (rm and finite (λ rate of increase were lower than control in treatment groups, significantly. From our investigations, pyriproxyfen is a good choice for control of the diamondback moth population through continuous generations.

  17. Remineralization of eroded enamel by a NaF rinse containing a novel calcium phosphate agent in an in situ model: a pilot study

    Directory of Open Access Journals (Sweden)

    Bennett T Amaechi

    2010-08-01

    Full Text Available Bennett T Amaechi1, Ramalingam Karthikeyan1, Poornima K Mensinkai1, Kaveh Najibfard1, Allen C Mackey2, Robert L Karlinsey21University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA; 2Indiana Nanotech, Indianapolis, IN, USAPurpose: An in situ study evaluated the remineralization potential of 225 ppm fluoride (F rinses with and without a calcium phosphate agent (TCP-Si-Ur on eroded enamel.Methods: 20 human patients participated in this IRB approved study. Enamel blocks extracted from 20 human molars were assigned to each of the three study phases (G1, G2, G3. Each block was eroded using 1% citric acid (pH = 2.5, with a slice cut from each block to establish baseline lesion parameters (ie, integrated mineral loss ∆Z, and lesion depth LD using ­transverse microradiography (TMR. Participants and assigned blocks were randomly divided into three 28-day phases. The blocks were mounted into modified orthodontic brackets and bonded to the buccal surface of one of the subject’s mandibular molars. The appliance remained in the ­subject’s mouth for 28 days. Prior to each study phase, participants observed a one-week-washout period using a fluoride-free dentifrice. In each phase, participants brushed with the fluoride-free ­dentifrice for 1 min, followed by one of the following coded treatments: G1: 225 ppm F + 40 ppm ­TCP-Si-Ur rinse (1 min; G2: 225 ppm F rinse (1 min; G3: no rinse (saliva-only. After each phase, appliances were removed and specimens were analyzed using TMR.Results: TMR data (ie, ∆Z and LD revealed all three groups significantly remineralized eroded enamel (paired t-tests, P , 0.001. Net mineralization (% change in ∆Z, LD were as follows (mean (std.dev.: G1: 44.1 (22.6, 30.5 (27.0; G2: 30.0 (7.4, 29.4 (10.5; G3: 23.8 (16.4, 25.7 (15.5. Furthermore, G1 was found to cause significantly more remineralization than G2 (P = 0.039 and G3, (P = 0.002.Conclusion: Mouthrinse containing 225 ppm F plus TCP

  18. Changes in the Expression of Biofilm-Associated Surface Proteins in Staphylococcus aureus Food-Environmental Isolates Subjected to Sublethal Concentrations of Disinfectants

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    Lenka Cincarova

    2016-01-01

    Full Text Available Sublethal concentrations (sub-MICs of certain disinfectants are no longer effective in removing biofilms from abiotic surfaces and can even promote the formation of biofilms. Bacterial cells can probably adapt to these low concentrations of disinfectants and defend themselves by way of biofilm formation. In this paper, we report on three Staphylococcus aureus biofilm formers (strong B+++, moderate B++, and weak B+ that were cultivated with sub-MICs of commonly used disinfectants, ethanol or chloramine T, and quantified using Syto9 green fluorogenic nucleic acid stain. We demonstrate that 1.25–2.5% ethanol and 2500 μg/mL chloramine T significantly enhanced S. aureus biofilm formation. To visualize differences in biofilm compactness between S. aureus biofilms in control medium, 1.25% ethanol, or 2500 μg/mL chloramine T, scanning electron microscopy was used. To describe changes in abundance of surface-exposed proteins in ethanol- or chloramine T-treated biofilms, surface proteins were prepared using a novel trypsin shaving approach and quantified after dimethyl labeling by LC-LTQ/Orbitrap MS. Our data show that some proteins with adhesive functions and others with cell maintenance functions and virulence factor EsxA were significantly upregulated by both treatments. In contrast, immunoglobulin-binding protein A was significantly downregulated for both disinfectants. Significant differences were observed in the effect of the two disinfectants on the expression of surface proteins including some adhesins, foldase protein PrsA, and two virulence factors.

  19. Surface remineralization potential of casein phosphopeptide-amorphous calcium phosphate on enamel eroded by cola-drinks: An in-situ model study

    Directory of Open Access Journals (Sweden)

    Navneet Grewal

    2013-01-01

    Full Text Available Aim: The aim of this study was to investigate the remineralization potential of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP on enamel eroded by cola drinks. Subjects and Methods: A total of 30 healthy subjects were selected from a random sample of 1200 children and divided into two groups of 15 each wherein calcium and phosphorus analyses and scanning electron microscope (SEM analysis was carried out to investigate the remineralization of enamel surface. A total of 30 non-carious premolar teeth were selected from the human tooth bank (HTB to prepare the in-situ appliance. Three enamel slabs were prepared from the same. One enamel slab was used to obtain baseline values and the other two were embedded into the upper palatal appliances prepared on the subjects′ maxillary working model. The subjects wore the appliance after which 30 ml cola drink exposure was given. After 15 days, the slabs were removed and subjected to respective analysis. Statistical Analysis Used: Means of all the readings of soluble calcium and phosphorous levels at baseline,post cola-drink exposure and post cpp-acp application were subjected to statistical analysis SPSS11.5 version.Comparison within groups and between groups was carried out using ANOVA and F-values at 1% level of significance. Results: Decrease in calcium solubility of enamel in the CPP-ACP application group as compared to post-cola drink exposure group (P < 0.05 was seen. Distinctive change in surface topography of enamel in the post-CPP-ACP application group as compared to post-cola drink exposure group was observed. Conclusion: CPP-ACP significantly promoted remineralization of enamel eroded by cola drinks as revealed by significant morphological changes seen in SEM magnification and spectrophotometric analyses.

  20. The effect of the Banton 300 oil-spill accident on marine life in Umm ...

    African Journals Online (AJOL)

    ... sponges, acorn barnacles, copepods, echinoderms and fish); sub-lethal disruption of physiological and/or behavioural activities (bacterioplankton, heterotrophic flagellates, and tintinnid ciliates); effects of direct coating (birds and mangroves); incorporation of hydrocarbons in organisms (crabs, scallops, edible mussels, ...