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Sample records for synthetic pyrethroid bifenthrin

  1. Toxicokinetics of the pyrethroid insecticide bifenthrin in blood and brain of the rat

    Science.gov (United States)

    Bifenthrin is a pyrethroid insecticide and human exposure to it can occur by oral, pulmonary and dermal routes. Pyrethroids are neurotoxic agents and it is generally believed that the parent pyrethroid is the toxic entity. The objective of this study was to assess the toxicokinet...

  2. Tissue time course and bioavailability of the pyrethroid insecticide bifenthrin in the Long-Evans rat

    Science.gov (United States)

    Bifenthrin is a pyrethroid insecticide and human exposure to it can occur by oral, pulmonary and dermal routes. Pyrethroids are neurotoxic agents and it is generally believed that the parent pyrethroid is the toxic entity. This study evaluated the oral disposition and bioavaila...

  3. Comparative metabolism of the pyrethroids bifenthrin and deltamethrin in the bulb mite Rhizoglyphus robini

    Energy Technology Data Exchange (ETDEWEB)

    Ruzo, L.O.; Cohen, E.; Capua, S. (The Hebrew Univ. of Jerusalem (Israel))

    The fate of {sup 14}C-radiolabeled bifenthrin and deltamethrin was studied in the mite, Rhizoglyphus robini. Administered either by ingestion or by contact, both pyrethroids were efficiently metabolized, but deltamethrin was degraded to a much greater extent. The identified metabolites arise from a combination of ester cleavage, oxidation, and conjugation reactions. With {sup 14}C-acid- and {sup 14}C-alcohol-labeled bifenthrin, the free metabolites detected were the 4{prime}-hydroxy derivative of the ester, the primary ester cleavage products, the acid, and its 4{prime}-hydroxy derivative from the alcohol moiety, as well as several unidentified metabolites. Using {sup 14}C-alcohol-labeled deltamethrin, 3-phenoxybenzoic acid and its 4{prime}-hydroxylated product and several unknown metabolites were detected. Conjugates comprised the bulk of total pyrethroid metabolites. In addition to ester cleavage products, the 4{prime}-hydroxylated bifenthrin was also identified. For the first time in invertebrates, a conjugated pyrethroid ester was observed.

  4. Mammal toxicology of synthetic pyrethroids.

    Science.gov (United States)

    Tsuji, Ryozo; Yamada, Tomoya; Kawamura, Satoshi

    2012-01-01

    Pyrethroids show moderate acute oral toxicity in rodents, and their typical toxicological signs are tremors (T syndrome) for Type I (generally non-cyano pyrethroids) and choreoathetosis with salivation (CS syndrome) for Type II (generally α-cyano pyrethroids). However, some pyrethroids show mixed clinical signs. Mainly Type II pyrethroids cause paresthesia, which is characterized by transient burning/tingling/itching sensation of the exposed skin. Also, it has been suggested that some pyrethroids cause developmental neurotoxicity, but available evidence has been judged to be insufficient. While some pyrethroids have been shown to cause tumors in rodent models, the tumor induction does not appear to reflect a common carcinogenic endpoint for this particular subset of compounds. Analysis of carcinogenic mode of action in some cases provides evidence not relevant in humans. Pyrethroids produce no common teratogenic effects in a particular species based on similarity in structure or mode of insecticidal action.

  5. Potentially toxic concentrations of synthetic pyrethroids associated with low density residential land use

    Directory of Open Access Journals (Sweden)

    Stephen Marshall

    2016-11-01

    Full Text Available Trace organic compounds associated with human activity are now ubiquitous in the environment. As the population becomes more urbanised and the use of pesticides and person care products continues to increase, urban waterways are likely to receive higher loads of trace organic contaminants with unknown ecological consequences. To establish the extent of trace organic contamination in urban runoff, concentrations of emerging chemicals of concern were determined in sediments from 99 urban wetlands in and around Melbourne, Australia between February and April, 2015. As a preliminary estimation of potential risks to aquatic biota, we compared measured concentrations with thresholds for acute and chronic toxicity, and modelled toxic units as a function of demographic and land use trends. The synthetic pyrethroid insecticide bifenthrin was common and widespread, and frequently occurred at concentrations likely to cause toxicity to aquatic life. Personal care products DEET and triclosan were common and widely distributed, while the herbicides diuron and prometryn, and the fungicides pyrimethanil and trifloxystrobin occurred less frequently. Toxic unit modelling using random forests found complex and unexpected associations between urban land uses and trace organic concentrations. Synthetic pyrethroid insecticides were identified as emerging compounds of concern, particularly bifenthrin. In contrast with previous surveys, the highest bifenthrin concentrations were associated with lower housing and population density, implicating low-density residential land use in bifenthrin contamination. We discuss the implications for pesticide regulation and urban wetland management in a global context.

  6. GC X GCTOFMS OF SYNTHETIC PYRETHROIDS IN FOODS SAMPLES

    Science.gov (United States)

    Pyrethrins are natural insecticides in the extract of chrysanthemum flowers1. Pyrethroids are synthetic forms of pyrethrins, and many are halogenated (F, Cl, Br). Synthetic pyrethroids have become popular replacements for organophosphorus pesticides, which have become increasin...

  7. Lethal and sublethal effects of the pyrethroid, bifenthrin, on grass shrimp (Palaemonetes pugio) and sheepshead minnow (Cyprinodon variegatus).

    Science.gov (United States)

    Harper, Heather E; Pennington, Paul L; Hoguet, Jennifer; Fulton, Michael H

    2008-08-01

    This study investigated the lethal and sublethal effects of the pyrethroid insecticide bifenthrin on adult and larval grass shrimp, Palaemonetes pugio, and adult sheepshead minnows, Cyprinodon variegatus. The effects were determined by conducting 96-h aqueous static renewal tests and 24-h static tests with sediment. Oxidative stress biomarkers, lipid peroxidation, glutathione, and catalase were also assessed. The 96-h aqueous LC50 value for adult shrimp was 0.020 microg/L (95% CI: 0.015-0.025 microg/L) and for larval shrimp was 0.013 microg/L (95% CI: 0.011-0.016 microg/L). The 96-h aqueous LC50 for adult sheepshead minnow was 19.806 microg/L (95% CI: 11.886-47.250 microg/L). The 24-h sediment LC50 for adult shrimp was 0.339 microg/L (95% CI: 0.291-0.381 microg/L) and for larval shrimp was 0.210 microg/L (95% CI: 0.096-0.393 microg/L). The oxidative stress assays showed some increasing trends toward physiological stress with increased bifenthrin concentrations but they were largely inconclusive. Given the sensitivity of grass shrimp to this compound in laboratory bioassays, additional work will be needed to determine if these exposure levels are environmentally relevant.

  8. Synergism between demethylation inhibitor fungicides or gibberellin inhibitor plant growth regulators and bifenthrin in a pyrethroid-resistant population of Listronotus maculicollis (Coleoptera: Curculionidae).

    Science.gov (United States)

    Ramoutar, D; Cowles, R S; Requintina, E; Alm, S R

    2010-10-01

    In 2007-2008, the "annual bluegrass weevil," Listronotus maculicollis Kirby (Coleoptera: Curculionidae), a serious pest of Poa annua L. (Poales: Poaceae) on U.S. golf courses, was shown to be resistant to two pyrethroids, bifenthrin and lambda-cyhalothrin. In 2008, we showed that bifenthrin resistance was principally mediated by oxidase detoxification (cytochrome P450 [P450]). P450s can be inhibited by demethylation inhibitor fungicides and gibberellin inhibitor plant growth regulators, both of which are commonly used on golf courses. We tested these compounds for synergistic activity with bifenthin against a pyrethroid-resistant population of L. maculicollis. The LD50 value for bifenthrin was significantly reduced from 87 ng per insect (without synergists) to 9.6-40 ng per insect after exposure to the fungicides fenarimol, fenpropimorph, prochloraz, propiconazole, and pyrifenox and the plant growth regulators flurprimidol, paclobutrazol, and trinexapac-ethyl. Simulated field exposure with formulated products registered for use on turf revealed enhanced mortality when adult weevils were exposed to bifenthrin (25% mortality, presented alone) combined with field dosages of propiconizole, fenarimol, flurprimidol, or trinexapac-ethyl (range, 49-70% mortality).

  9. Spectroscopic studies on the photochemical decarboxylation mechanisms of synthetic pyrethroids.

    Science.gov (United States)

    Suzuki, Yusuke; Ishizaka, Shoji; Kitamura, Noboru

    2012-12-01

    A novel radical trapping technique combined with a fluorescence spectroscopic analysis has been employed to investigate the radical intermediates produced by photodecarboxylation of four synthetic pyrethroids: fenvalerate (SMD), fenpropathrin (DTL), cyphenothrin (GKL), and cypermethrin (AGT). Under photoirradiation at >290 nm, all pyrethroids underwent direct photolysis via homolytic cleavage of the carbon-oxygen bonds in the ester groups. The consumed amount of a nitroxide free radical, as a trapping agent for the intermediate radical of a pyrethroid, was determined by ESR, which was the measure of the reaction yield of a photochemically generated α-cyano-3-phenoxybenzyl radical common to all pyrethroids. The reactivities of the pyrethroids studied was in the sequence of SMD > DTL > GKL > AGT. Furthermore, nanosecond transient absorption spectroscopy demonstrated that geminate recombination of the radical pair within a solvent cage is the main deactivation route of the photochemically generated α-cyano-3-phenoxybenzyl radical common for all pyrethroids studied.

  10. Biomarkers of Type II Synthetic Pyrethroid Pesticides in Freshwater Fish

    Directory of Open Access Journals (Sweden)

    Anilava Kaviraj

    2014-01-01

    Full Text Available Type II synthetic pyrethroids contain an alpha-cyano group which renders them more neurotoxic than their noncyano type I counterparts. A wide array of biomarkers have been employed to delineate the toxic responses of freshwater fish to various type II synthetic pyrethroids. These include hematological, enzymatic, cytological, genetic, omic and other types of biomarkers. This review puts together the applications of different biomarkers in freshwater fish species in response to the toxicity of the major type II pyrethroid pesticides and assesses their present status, while speculating on the possible future directions.

  11. Stability of the pyrethroid pesticide bifenthrin in milled wheat during thermal processing, yeast and lactic acid fermentation, and storage.

    Science.gov (United States)

    Dorđević, Tijana M; Šiler-Marinković, Slavica S; Ðurović, Rada D; Dimitrijević-Branković, Suzana I; Gajić Umiljendić, Jelena S

    2013-10-01

    Pesticide residues have become an unavoidable part of food commodities. In the context of increased interest for food processing techniques as a tool for reducing pesticide residues, it is interesting to study the potential loss of pesticides during lactic acid and yeast fermentation. In the present paper the effect of fermentation by Lactobacillus plantarum and Saccharomyces cerevisiae and storage on 23 °C on bifenthrin in wheat was investigated. In addition, the effect of sterilisation (applied in order to avoid contamination with wild microorganism strains, i.e. to determine the individual effects of used strains) on bifenthrin degradation was tested as well. No significant loss of bifenthrin was observed during storage, or after the sterilisation. During the lactic acid fermentation, reduction within wheat fortified with 0.5 mg kg(-1) was 42%, while quite lower within samples fortified with 2.5 mg kg(-1) , maximum 18%. In contrast, bifenthrin concentration was not reduced during yeast fermentation, as the reduction in fortified samples was in the range of spontaneous chemical degradation during incubation period. Possible bifenthrin contamination in wheat, in amounts over the maximum residue limits, could not be reduced by sterilisation or by yeast fermentation, but lactic acid fermentation could be an effective tool for minimising residual contamination. © 2013 Society of Chemical Industry.

  12. Strategic control of ticks with synthetic pyrethroids in Theileria parva ...

    African Journals Online (AJOL)

    The effect of tick control by strategic dipping in synthetic pyrethroids on growth and survival rates of calves in Eastern Tanzania where Theileria parva and other tick borne infections (babesiosis, anaplasmosis and ehrlichiosis) are endemic was measured. One day to five months old Tanganyika short horn zebu (Bos indicus) ...

  13. A method for the simultaneous quantification of eight metabolites of synthetic pyrethroids in urine of the general population using gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Schettgen, Thomas; Dewes, Petra; Kraus, Thomas

    2016-08-01

    Synthetic pyrethroids are highly effective, widespread insecticides applied worldwide for different purposes. Among the possible sources of exposure for the general population, pyrethroid residues in food and their prominent use for the conservation of wool carpets or in indoor pest control might play a major role. On the basis of previous works, we have developed and validated a highly sensitive and specific GC/MS/MS-method to simultaneously quantify the metabolites of the most common synthetic pyrethroids in urine, namely cis- and trans-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (DCCA), cis-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylic acid (DBCA), 4-fluoro-3-phenoxybenzoic acid (F-PBA), 3-phenoxybenzoic acid (3-PBA) as well as the metabolites cis-3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethyl-cyclopropanecarboxylic acid (ClF3CA, λ-cyhalothrin/bifenthrin), 4-chloro-α-isopropylbenzene acetic acid (CPBA, esfenvalerate), and 2-methyl-3-phenylbenzoic acid (MPB, bifenthrin). After acidic hydrolysis to cleave conjugates in urine, the analytes are subjected to a pH-controlled extraction into n-hexane. After concentration, the analytes are derivatised using MTBSTFA and finally quantified by GC/MS/MS in EI-mode using d6-trans-DCCA and (13)C6-3-PBA as internal standards. The limit of quantification for these metabolites was 0.01 μg/L urine. Precision within and between series was determined to range between 1.6 and 10.7 % using a native quality control sample as well as a urine sample spiked with 0.3 μg/L of the analytes. To investigate possible background excretions, we analysed spot urine samples of 38 persons of the general population in a pilot study. cis- and trans-DCCA as well as 3-PBA could be quantified in every urine sample investigated, while MPB and F-PBA could only be detected in two samples. The median levels for excretion of cis-DCCA, trans-DCCA, 3-PBA, ClF3CA, DBCA, CPBA, F-PBA and MPA were 0.08, 0.17, 0.22, 0.04, 0

  14. Environmental modeling and exposure assessment of sediment-associated pyrethroids in an agricultural watershed.

    Directory of Open Access Journals (Sweden)

    Yuzhou Luo

    Full Text Available Synthetic pyrethroid insecticides have generated public concerns due to their increasing use and potential effects on aquatic ecosystems. A modeling system was developed in this study for simulating the transport processes and associated sediment toxicity of pyrethroids at coupled field/watershed scales. The model was tested in the Orestimba Creek watershed, an agriculturally intensive area in California' Central Valley. Model predictions were satisfactory when compared with measured suspended solid concentration (R(2 = 0.536, pyrethroid toxic unit (0.576, and cumulative mortality of Hyalella azteca (0.570. The results indicated that sediment toxicity in the study area was strongly related to the concentration of pyrethroids in bed sediment. Bifenthrin was identified as the dominant contributor to the sediment toxicity in recent years, accounting for 50-85% of predicted toxicity units. In addition, more than 90% of the variation on the annual maximum toxic unit of pyrethroids was attributed to precipitation and prior application of bifenthrin in the late irrigation season. As one of the first studies simulating the dynamics and spatial variability of pyrethroids in fields and instreams, the modeling results provided useful information on new policies to be considered with respect to pyrethroid regulation. This study suggested two potential measures to efficiently reduce sediment toxicity by pyrethroids in the study area: [1] limiting bifenthrin use immediately before rainfall season; and [2] implementing conservation practices to retain soil on cropland.

  15. Environmental Modeling and Exposure Assessment of Sediment-Associated Pyrethroids in an Agricultural Watershed

    Science.gov (United States)

    Luo, Yuzhou; Zhang, Minghua

    2011-01-01

    Synthetic pyrethroid insecticides have generated public concerns due to their increasing use and potential effects on aquatic ecosystems. A modeling system was developed in this study for simulating the transport processes and associated sediment toxicity of pyrethroids at coupled field/watershed scales. The model was tested in the Orestimba Creek watershed, an agriculturally intensive area in California' Central Valley. Model predictions were satisfactory when compared with measured suspended solid concentration (R2 = 0.536), pyrethroid toxic unit (0.576), and cumulative mortality of Hyalella azteca (0.570). The results indicated that sediment toxicity in the study area was strongly related to the concentration of pyrethroids in bed sediment. Bifenthrin was identified as the dominant contributor to the sediment toxicity in recent years, accounting for 50–85% of predicted toxicity units. In addition, more than 90% of the variation on the annual maximum toxic unit of pyrethroids was attributed to precipitation and prior application of bifenthrin in the late irrigation season. As one of the first studies simulating the dynamics and spatial variability of pyrethroids in fields and instreams, the modeling results provided useful information on new policies to be considered with respect to pyrethroid regulation. This study suggested two potential measures to efficiently reduce sediment toxicity by pyrethroids in the study area: [1] limiting bifenthrin use immediately before rainfall season; and [2] implementing conservation practices to retain soil on cropland. PMID:21246035

  16. Environmental effects and fate of the insecticide bifenthrin in a salt-marsh mesocosm.

    Science.gov (United States)

    Pennington, Paul L; Harper-Laux, Heather; Sapozhnikova, Yelena; Fulton, Michael H

    2014-10-01

    Bifenthrin is a widely used synthetic pyrethroid insecticide that is often applied to crops, turf, and residential structures for the control of insects. Like other insecticides, bifenthrin has the potential to contaminate bodies of water that are adjacent to the application site via spray drift and runoff during storm events. The objective of this study was to examine the lethal and sublethal effects of bifenthrin on grass shrimp, Palaemonetes pugio, and sheepshead minnow, Cyprinodon variegatus in a 28 d mesocosm experiment under estuarine conditions. Endpoints included mortality and growth and the oxidative stress biomarkers of lipid peroxidation, glutathione, and catalase. In the mesocosm experiment, 24 h and 96 h caged shrimp LC50s were 0.061 and 0.051 μg L(-1), respectively. The uncaged grass shrimp 28 d LC50 was 0.062 μg L(-1). Fifty percent mortality was not reached in the uncaged sheepshead minnow. Bifenthrin did not have a significant effect on the growth of the shrimp, but there was an increasing impact on fish growth. However, it is uncertain as to whether this pattern is a direct effect of the chemical or if it is due to increased food availability resulting from mortality in prey species. The oxidative stress assays were largely inconclusive. Bifenthrin was eliminated rapidly from the water column and readily partitioned to sediments. The LC50s for adult and larval P. pugio were below published Estimated Environmental Concentration (EEC) values and were within the range of bifenthrin concentrations that have been measured in rivers, channels, and creeks. Published by Elsevier Ltd.

  17. Monoclonal antibodies to synthetic pyrethroids and method for detecting the same

    Energy Technology Data Exchange (ETDEWEB)

    Stanker, L.H.; Vanderlaan, M.; Watkins, B.E.; Van Emon, J.M.; Bigbee, C.L.

    1992-04-28

    Methods are described for making specific monoclonal antibodies which may be used in a sensitive immunoassay for detection of synthetic pyrethroids in foods and environmental samples. Appropriate sample preparation and enzyme amplification of the immunoassay for this widely-used class of pesticides permits detection at low levels in laboratory and field tested samples. 6 figs.

  18. Monoclonal antibodies to synthetic pyrethroids and method for detecting the same

    Energy Technology Data Exchange (ETDEWEB)

    Stanker, Larry H. (Livermore, CA); Vanderlaan, Martin (Danville, CA); Watkins, Bruce E. (Livermore, CA); Van Emon, Jeanette M. (Henderson, NV); Bigbee, Carolyn L. (Livermore, CA)

    1992-01-01

    Methods are described for making specific monoclonal antibodies which may be used in a sensitive immunoassay for detection of synthetic pyrethroids in foods and environmental samples. Appropriate sample preparation and enzyme amplification of the immunoassay for this widely-used class of pesticides permits detection at low levels in laboratory and field tested samples.

  19. Topical treatment of calves with synthetic pyrethroids: effects on the non-target dung fly Neomyia cornicina (Diptera: Muscidae)

    DEFF Research Database (Denmark)

    Sommer, C.; Jensen, Karl-Martin Vagn; Jespersen, Jørgen B.

    2001-01-01

    Dung from calves treated with synthetic pyrethroids negatively influenced, in varying degrees, survival, reproduction and size of the common dung fly Neomyia cornicina (Fabricius). This was documented in assays where the coprophagous larvae and adults of N. cornicina were exposed to dung collected......). Fluctuating asymmetry of a wing vein character did not reflect the anticipated levels of exposure. The study strongly indicated that the use of synthetic pyrethroids affected the insect dung fauna and that such use may reduce dung decomposition....

  20. Acute exposure to synthetic pyrethroids causes bioconcentration and disruption of the hypothalamus–pituitary–thyroid axis in zebrafish embryos

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Wenqing [Research Institute of Poyang Lake, Jiangxi Academy of Sciences, Nanchang 330029 (China); Institute of Environmental Science, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Xu, Chao, E-mail: chaoxu@zjut.edu.cn [Institute of Environmental Science, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Lu, Bin; Lin, Chunmian [Institute of Environmental Science, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Wu, Yongming [Research Institute of Poyang Lake, Jiangxi Academy of Sciences, Nanchang 330029 (China); Liu, Weiping [Institute of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)

    2016-01-15

    Synthetic pyrethroids (SPs) have the potential to disrupt the thyroid endocrine system in mammals; however, little is known of the effects of SPs and underlying mechanisms in fish. In the current study, embryonic zebrafish were exposed to various concentrations (1, 3 and 10 μg/L) of bifenthrin (BF) or λ-cyhalothrin (λ-CH) until 72 h post fertilization, and body condition, bioaccumulation, thyroid hormone levels and transcription of related genes along the hypothalamus–pituitary–thyroid (HPT) axis examined. Body weight was significantly decreased in the λ-CH exposure groups, but not the BF exposure groups. BF and λ-CH markedly accumulated in the larvae, with concentrations ranging from 90.7 to 596.8 ng/g. In both exposure groups, alterations were observed in thyroxine (T{sub 4}) and triiodothyronine (T{sub 3}) levels. In addition, the majority of the HPT axis-related genes examined, including CRH, TSHβ, TTR, UGT1ab, Pax8, Dio2 and TRα, were significantly upregulated in the presence of BF. Compared to BF, λ-CH induced different transcriptional regulation patterns of the tested genes, in particular, significant stimulation of TTR, Pax8, Dio2 and TRα levels along with concomitant downregulation of Dio1. Molecular docking analyses revealed that at the atomic level, BF binds to thyroid hormone receptor (TRα) protein more potently than λ-CH, consequently affecting HPT axis signal transduction. In vitro and in silico experiments disclosed that during the early stages of zebrafish development, BF and λ-CH have the potential to disrupt thyroid endocrine system. - Highlights: • Following respective exposure of embryos to BF and λ-CH, thyroid endocrine disruption was investigated in zebrafish embryos. • Thyroid hormones (T3 and T4 levels) were significantly altered after being exposed to BF and λ-CH. • Gene transcription modulation in the HPT axis was examined. • BF and λ-CH bioconcentration in zebrafish larvae were evident. • BF binds to thyroid

  1. Toxicity of synthetic pyrethroid insecticides to the grass shrimp, Palaemonetes pugio, parasitized with the bopyrid isopod, Probopyrus pandalicola.

    Science.gov (United States)

    Williamson, Christopher J; Pennington, Paul L; Curran, Mary Carla

    2009-11-01

    The grass shrimp, Palaemonetes pugio, plays a large role in the marine ecosystem, serving as a vital link in the food web between many other species. Marine parasites such as the bopyrid isopod, Probopyrus pandalicola, reduce shrimp growth and reproductive output and may also cause P. pugio to be more vulnerable to the lethal effects of contaminants. The purpose of this study was to determine the toxicity of resmethrin and bifenthrin on the grass shrimp, P. pugio, infected with the bopyrid isopod, Probopyrus pandalicola. A 96-h static renewal test was conducted to determine the toxicity of the pyrethroid insecticides resmethrin and bifenthrin to grass shrimp, Palaemonetes pugio, parasitized with the bopyrid isopod, Probopyrus pandalicola. The results were then compared to similar tests utilizing unparasitized P. pugio. Parasitized P. pugio had lower 24-h LC(50) (1.08 microg/L) and 96-h LC(50) (0.43 microg/L) values for resmethrin than unparasitized P. pugio. However, LC(50) ratio tests found that there was no significant difference between parasitized and unparasitized shrimp when affected by resmethrin (p = 0.1751 and 0.1108, respectively). In contrast, an LC(10) ratio test indicated that there was a significant difference between parasitized and unparasitized P. pugio after 96 h (p shrimp, P. pugio, regardless of parasite presence, and parasitized shrimp may be more susceptible to lower doses of resmethrin (when exposed in the field).

  2. Characterization of Diastereo- and Enantioselectivity in Degradation of Synthetic Pyrethroids in Soils.

    Science.gov (United States)

    Li, Shaotong; Li, Zhaoyang; Li, Qiaoling; Zhao, Jiahe; Li, Sen

    2016-01-01

    Permethrin (PM), cypermethrin (CP), and cyfluthrin (CF) are three important synthetic pyrethroids, which contain two, four, and four enantiomeric pairs (diastereomers) and thus have four, eight, and eight stereoisomers, respectively. In this study, the stereo- and enantioselective degradation of PM, CP, and CF in a Shijiazhuang alkaline yellow soil and a Wuhan acidic red soil were studied in detail by a combination of achiral and chiral high-performance liquid chromatography (HPLC). The results showed that PM, CP, and CF degraded faster in Shijiazhuang soil than in Wuhan soil, and the dissipation rate followed an order of PM > CF > CP in both soils. The three pyrethroids exhibited similar diastereomer selectivity, while CP and CF showed higher enantioselectivity than PM. Moreover, the trans-diastereomers degraded faster, and showed higher enantioselectivity than the corresponding cis-diastereomers. For PM, the enantiomer 1S-trans-PM degraded most rapidly in both soils. As for CP and CF, the highest enantioselectivity was observed for diastereomer trans-3, and the insecticidally active enantiomer 1R-trans-αS degraded fastest among the 8 CP or CF stereoisomers in both soils. In addition, the Wuhan acidic soil displayed higher diastereomer and enantiomer selectivity than the Shijiazhuang alkaline soil for the three pyrethroids. Further incubation of CF in an alkaline-treated Wuhan soil showed that the dissipation rate greatly increased and the diastereo- and enantioselectivity significantly decreased after the alkaline treatment process. © 2015 Wiley Periodicals, Inc.

  3. Collembola and macroarthropod community responses to carbamate, organophosphate and synthetic pyrethroid insecticides: Direct and indirect effects

    International Nuclear Information System (INIS)

    Frampton, Geoff K.; Brink, Paul J. van den

    2007-01-01

    Non-target effects on terrestrial arthropod communities of the broad-spectrum insecticides chlorpyrifos and cypermethrin and the selective insecticide pirimicarb were investigated in winter wheat fields in summer. Effects of chlorpyrifos on arthropod abundance and taxonomic richness were consistently negative whereas effects of cypermethrin were negative for predatory arthropods but positive for soil surface Collembola. Pirimicarb effects were marginal, primarily on aphids and their antagonists, with no effect on the Collembola community. Collembola-predator ratios were significantly higher following cypermethrin treatment, suggesting that cypermethrin-induced increases in collembolan abundance represent a classical resurgence. Observations in other studies suggest Collembola resurgences may be typical after synthetic pyrethroid applications. Collembola responses to insecticides differed among species, both in terms of effect magnitude and persistence, suggesting that coarse taxonomic monitoring would not adequately detect pesticide risks. These findings have implications for pesticide risk assessments and for the selection of indicator species. - Direct and indirect insecticide effects differ among closely-related arthropod taxa; resurgence of Collembola may occur widely after synthetic pyrethroid insecticide applications

  4. The antioxidative response system in Glycine max (L.) Merr. exposed to Deltamethrin, a synthetic pyrethroid insecticide

    Energy Technology Data Exchange (ETDEWEB)

    Bashir, Fozia [Department of Botany, Faculty of Science, Jamia Hamdard, New Delhi 110062 (India); Mahmooduzzafar [Department of Botany, Faculty of Science, Jamia Hamdard, New Delhi 110062 (India); Siddiqi, T.O. [Department of Botany, Faculty of Science, Jamia Hamdard, New Delhi 110062 (India); Iqbal, Muhammad [Department of Botany, Faculty of Science, Jamia Hamdard, New Delhi 110062 (India)]. E-mail: iqbalg5@yahoo.co.in

    2007-05-15

    Forty-five-day-old plants of Glycine max (soybean) were exposed to several Deltamethrin (synthetic pyrethroid insecticide) concentrations (0.00 %, 0.05 %, 0.10 %, 0.15 % and 0.20 %) through foliar spray in the field conditions. In the treated plants, as observed at the pre-flowering (10 DAT), flowering (45 DAT) and post-flowering (70 DAT) stages, lipid peroxidation, proline content and total glutathione content increased, whereas the total ascorbate content decreased, as compared with the control. Among the enzymatic antioxidants, activity of superoxide dismutase, ascorbate peroxidase and glutathione reductase increased significantly whereas that of catalase declined markedly in relation to increasing concentration of Deltamethrin applied. The changes observed were dose-dependent, showing a strong correlation with the degree of treatment. - The Deltamethrin-induced oxidative stress alters the ascorbate-glutathione cycle in Glycine max.

  5. The antioxidative response system in Glycine max (L.) Merr. exposed to Deltamethrin, a synthetic pyrethroid insecticide

    International Nuclear Information System (INIS)

    Bashir, Fozia; Mahmooduzzafar; Siddiqi, T.O.; Iqbal, Muhammad

    2007-01-01

    Forty-five-day-old plants of Glycine max (soybean) were exposed to several Deltamethrin (synthetic pyrethroid insecticide) concentrations (0.00 %, 0.05 %, 0.10 %, 0.15 % and 0.20 %) through foliar spray in the field conditions. In the treated plants, as observed at the pre-flowering (10 DAT), flowering (45 DAT) and post-flowering (70 DAT) stages, lipid peroxidation, proline content and total glutathione content increased, whereas the total ascorbate content decreased, as compared with the control. Among the enzymatic antioxidants, activity of superoxide dismutase, ascorbate peroxidase and glutathione reductase increased significantly whereas that of catalase declined markedly in relation to increasing concentration of Deltamethrin applied. The changes observed were dose-dependent, showing a strong correlation with the degree of treatment. - The Deltamethrin-induced oxidative stress alters the ascorbate-glutathione cycle in Glycine max

  6. Comparing the impacts of sediment-bound bifenthrin on aquatic macroinvertebrates in laboratory bioassays and field microcosms.

    Science.gov (United States)

    Boyle, Rhianna L; Hoak, Molly N; Pettigrove, Vincent J; Hoffmann, Ary A; Long, Sara M

    2016-11-01

    We conducted two laboratory bioassays and two field microcosm exposures with bifenthrin (a synthetic pyrethroid) in order to evaluate the capacity of single-species laboratory bioassays to predict lethal and sublethal impacts on aquatic invertebrates in microcosms. For the laboratory species, Chironomus tepperi, larval survival was reduced by 24% at 53.66µg/g OC, while adult emergence was reduced at concentrations of 33.33µg/g OC and higher, with a 61% decrease at 77.78µg/g OC and no emergence at 126.67µg/g OC. The abundance of several other microcosm taxa was reduced in the microcosms at a similar concentration range (33.33µg/g OC and above), however there was no impact on the abundance of the congeneric species, Chironomus oppositus. The differences in impacts between test systems were potentially due to both differing species sensitivity and the interaction of ambient temperature with bifenthrin toxicity. Bifenthrin also was associated with early emergence of Chironomus sp. in both test systems, at concentrations of 10µg/g OC and higher (laboratory) and 43.90µg/g OC (microcosm), and with a significant decrease in the proportion of C. oppositus males in a microcosm. These findings indicate that while laboratory bioassays accurately predict many impacts in the field, there are some limitations to the predictive capacity of these tests. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Recurrent tonic-clonic seizures and coma due to ingestion of Type I pyrethroids in a 19-month-old patient.

    Science.gov (United States)

    Giampreti, A; Lampati, L; Chidini, G; Rocchi, L; Rolandi, L; Lonati, D; Petrolini, V M; Vecchio, S; Locatelli, C A; Manzo, L

    2013-07-01

    Pyrethroids are synthetic pyrethrin analogues that induce sodium-channel depolarization and hyperexcitation. Severe pyrethroid poisoning is manifested by a "Tremor Syndrome" (Type I cyano-agents) or a "Choreoathetosis/Salivation Syndrome" (Type II non cyano-agents). Very few reports of neurotoxic effects caused by Type I pyrethroids ingestion are available, and no human data concerning Type I pyrethroid blood levels in pediatric poisoning are reported in the medical literature. A 19-month-old female patient presented with irritability and inconsolable crying that rapidly worsened to tonic-clonic seizures and coma (GCS 6). On admission vital signs including BP 110/70 mmHg, HR 110 beats/min, and SpO2 98% on room air were normal. Orotracheal intubation, oxygen administration, and midazolam infusion (4 μg/kg/min) were performed. Intravenous thiopental sodium, up to 18 mg/kg/hour, was administered to control convulsions. An inquiry revealed that 9 h before presentation the patient had ingested an unknown amount of an insecticide containing 7% piperonyl-butoxide and a mixture of the Type I pyrethroids bifenthrin (5%) and esbiothrin (3%). Consequently, gastric lavage was performed, followed by administration of activated charcoal and cathartics. On the subsequent 48 h, the patient returned progressively alert; she was extubated on day 4 and discharged asymptomatically 12 days after hospitalization. After 9, 48, and 72 h of ingestion, the plasma levels were 500, 95, and 40 ng/mL for bifenthrin and 1,640, 640, and 165 ng/mL for piperonyl-butoxide respectively. This pediatric case showed severe pyrethroid neurotoxicity associated with measurable plasma levels of bifenthrin and piperonyl-butoxide. In pediatric pyrethroid poisoning, coma and seizures may represent the main life-threatening features. First-aid therapy including airway maintenance and control of muscle fasciculation and seizures is of major importance. Benzodiazepines and high-dose thiopental sodium were

  8. Use and abuse of pyrethrins and synthetic pyrethroids in veterinary medicine.

    Science.gov (United States)

    Anadón, A; Martínez-Larrañaga, M R; Martínez, M A

    2009-10-01

    Pyrethrin and pyrethroid insecticides are widely used in veterinary medicine for agricultural and domestic purposes. Although pyrethrins and pyrethroids are generally regarded as safe to animals, there have been reports of systemic poisoning in veterinary species. This review summarises the use of pyrethrins and pyrethroids in companion and food producing animals, including their mechanism of action and toxicity. The toxicokinetics of pyrethrins and pyrethroids are described, including absorption, distribution, metabolism (including interactions with other compounds affecting drug metabolising enzymes) and excretion, leading to the application of toxicokinetic/toxicodynamic concepts. Specific cases of pyrethroid poisoning in laboratory animals (including age-related toxicity), fish, companion and large animals are considered, including the high incidence of feline pyrethroids toxicosis following the extra-label use of topical formulations.

  9. The impact of synthetic pyrethroid and organophosphate sheep dip formulations on microbial activity in soil

    Energy Technology Data Exchange (ETDEWEB)

    Boucard, Tatiana K.; McNeill, Charles [Department of Environmental Science, Faculty of Science and Technology, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Bardgett, Richard D. [Department of Biological Sciences, Faculty of Science and Technology, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Paynter, Christopher D. [Department of Environmental Science, Faculty of Science and Technology, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Semple, Kirk T. [Department of Environmental Science, Faculty of Science and Technology, Lancaster University, Lancaster LA1 4YQ (United Kingdom)], E-mail: k.semple@lancaster.ac.uk

    2008-05-15

    Sheep dip formulations containing organophosphates (OPs) or synthetic pyrethroids (SPs) have been widely used in UK, and their spreading onto land has been identified as the most practical disposal method. In this study, the impact of two sheep dip formulations on the microbial activity of a soil was investigated over a 35-d incubation. Microbial utilisation of [1-{sup 14}C] glucose, uptake of {sup 14}C-activity into the microbial biomass and microbial numbers (CFUs g{sup -1} soil) were investigated. In control soils and soils amended with 0.01% sheep dip, after 7 d a larger proportion of added glucose was allocated to microbial biomass rather than respired to CO{sub 2}. No clear temporal trends were found in soils amended with 0.1% and 1% sheep dips. Both sheep dip formulations at 0.1% and 1% concentrations resulted in a significant increase in CFUs g{sup -1} soil and [1-{sup 14}C] glucose mineralisation rates, as well as a decline in microbial uptake of [1-{sup 14}C] glucose, compared to control and 0.01% SP- or OP-amended soils. This study suggests that the growth, activity, physiological status and/or structure of soil microbial community may be affected by sheep dips. - The application of sheep dip formulations can have a profound impact upon microbial activity and substrate utilisation in soil.

  10. The treatment and eradication of sheep lice and ked with cyhalothrin--a new synthetic pyrethroid.

    Science.gov (United States)

    Rundle, J C; Forsyth, B A

    1984-12-01

    A new synthetic pyrethroid, cyhalothrin, has been evaluated as both a sheep dip and a jetting fluid for the control of body lice (Damalinia ovis), face lice (Linognathus ovillus), foot lice (Linognathus pedalis) and the sheep ked (Melophagus ovinus). A dip wash concentration of 1.25 ppm cyhalothrin eradicated D. ovis from sheep. A jetting fluid at a concentration of 20 ppm also eradicated D. ovis. In the field cyhalothrin was evaluated at 20 ppm as a dip wash and at 50 ppm as a jetting fluid. These field trials confirmed the ability of cyhalothrin to eradicate D. ovis from short and long-woolled sheep. The sucking lice, L. ovillus and L. pedalis, were also found to be very susceptible to cyhalothrin at a dip wash concentration of 20 ppm, but it was necessary to treat the predilection sites infested by these parasites twice within a 3-week period to achieve their eradication. Sheep ked (M. ovinus) were eradicated from an infected flock of sheep after plunge dipping in cyhalothrin at 20 ppm.

  11. Cross-resistance Patterns to Insecticides of Several Chemical Classes Among Listronotus maculicollis (Coleoptera: Curculionidae) Populations With Different Levels of Resistance to Pyrethroids.

    Science.gov (United States)

    Kostromytska, Olga S; Wu, Shaohui; Koppenhöfer, Albrecht M

    2018-02-09

    The annual bluegrass weevil (ABW), Listronotus maculicollis Kirby (Coleoptera: Curculionidae), is the most damaging golf course insect pest in eastern North America. Heavy reliance on synthetic insecticides against this pest has led to widespread problems in controlling ABW with pyrethroid resistance already reported from populations in southern New England. This study evaluated the degree and scope of ABW resistance, determined existing cross-resistance patterns, and confirmed laboratory findings under greenhouse conditions. The susceptibility of 10 ABW populations to insecticides of different chemical classes was assessed in topical, feeding, and greenhouse assays. The level of susceptibility to pyrethroids varied significantly among populations (LD50s ranging 2.4-819.1 ng per insect for bifenthrin and 1.1-362.7 ng for λ-cyhalothrin in the topical assay). Three populations were relatively susceptible to pyrethroids, and seven populations had moderate to high resistance levels (RR50 for bifenthrin ranging 30.5-343.1). The toxicity of chlorpyrifos (RR50s ranging 3.3-15.3), spinosad (RR50s 2.4-7.7), clothianidin (RR50s 4.2-9.7), and indoxacarb (RR50s 2.8-9.7) was decreased for the pyrethroid-resistant populations. Toxicity data for bifenthrin and chlorpyrifos obtained under more realistic greenhouse conditions confirmed laboratory observations, indicating that the topical assay is an accurate method of detection and measurement of resistance level. The current study expanded the previously known geographic range of ABW pyrethroid resistance to include the New York metropolitan area, New Jersey, and eastern Pennsylvania and provided clear evidence of cross-resistance not only within the pyrethroid class but also to several other chemical classes. © 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.

  12. Synergistic potential of dillapiole-rich essential oil with synthetic pyrethroid insecticides against fall armyworm

    OpenAIRE

    Fazolin, Murilo; Estrela, Joelma Lima Vidal; Medeiros, André Fábio Monteiro; Silva, Iriana Maria da; Gomes, Luiara Paiva; Silva, Maria Samylla de Farias

    2016-01-01

    ABSTRACT: The objective of this study was to evaluate the synergy and response homogeneity of the Spodoptera frugiperda larvae population to the Piper aduncum essential oil in combination with pyrethroid insecticides (alpha-cypermethrin, beta-cypermethrin, fenpropathrin, and gamma-cyhalothrin) compared to piperonylbutoxide (PBO) as positive control. Synergism (SF) comparisons were obtained using lethal concentration (LC50) and lethal dose (LD50) ratios of insecticides individually and in thei...

  13. Analysis of the synthetic pyrethroids, permethrin and 1(R)-phenothrin, in grain using a monoclonal antibody-based test

    Energy Technology Data Exchange (ETDEWEB)

    Skerritt, J.H.; Hill, A.S. (CSIRO Division of Plant Industry, North Ryde (Australia)); McAdam, D.P. (CSIRO Division of Plant Industry, Canberra (Australia)); Stanker, L.H. (University of California, Livermore (United States))

    1992-07-01

    A monoclonal antibody generated to the synthetic pyrethroid-related hapten, (3-phenoxybenzyl)-2,2-dimethylcyclopropane-1, 3-dicarboxylate-protein conjugate, was used to develop assays for determinations of permethrin and 1(R)-phenothrin in wheat grain and flour milling fractions. The earlier 3-h assay was simplified using two approaches. The antibody was directly conjugated to the enzyme horseradish peroxidase (HRP), which removes a separate incubation and washing step from the assay. Also, an assay has been developed using microwell-bound monoclonal antibody and a HRP-labeled 3-phenoxybenzoic acid derivative. These assay formats have advantages in increased sensitivity and, in the case of the latter assay, accuracy with grain and flour samples. The most sensitive assay format could detect 1.5 ng/mL permethrin; 50% inhibition of antibody binding occurred at 10 ng/mL. These values corresponded to 75 and 500 ppb, respectively, in the original wheat sample. Methanol was the most effective pyrethroid extractant. Use of a simple cleanup procedure for ground grain extracts improved ELISA accuracy but could by omitted for screening purposes.

  14. Isomer-specific comparisons of the hydrolysis of synthetic pyrethroids and their fluorogenic analogues by esterases from the cotton bollworm Helicoverpa armigera.

    Science.gov (United States)

    Yuan, G; Li, Y; Farnsworth, C A; Coppin, C W; Devonshire, A L; Scott, C; Russell, R J; Wu, Y; Oakeshott, J G

    2015-06-01

    The low aqueous solubility and chiral complexity of synthetic pyrethroids, together with large differences between isomers in their insecticidal potency, have hindered the development of meaningful assays of their metabolism and metabolic resistance to them. To overcome these problems, Shan and Hammock (2001) [7] therefore developed fluorogenic and more water-soluble analogues of all the individual isomers of the commonly used Type 2 pyrethroids, cypermethrin and fenvalerate. The analogues have now been used in several studies of esterase-based metabolism and metabolic resistance. Here we test the validity of these analogues by quantitatively comparing their hydrolysis by a battery of 22 heterologously expressed insect esterases with the hydrolysis of the corresponding pyrethroid isomers by these esterases in an HPLC assay recently developed by Teese et al. (2013) [14]. We find a strong, albeit not complete, correlation (r = 0.7) between rates for the two sets of substrates. The three most potent isomers tested were all relatively slowly degraded in both sets of data but three esterases previously associated with pyrethroid resistance in Helicoverpa armigera did not show higher activities for these isomers than did allelic enzymes derived from susceptible H. armigera. Given their amenability to continuous assays at low substrate concentrations in microplate format, and ready detection of product, we endorse the ongoing utility of the analogues in many metabolic studies of pyrethroids. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Integrative assessment of enantioselectivity in endocrine disruption and immunotoxicity of synthetic pyrethroids

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Meirong [Research Center of Environmental Science, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Chen Fang [College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China); Wang Cui; Zhang Quan [Research Center of Environmental Science, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Gan Jianying [Department of Environmental Sciences, University of California, Riverside, CA 92521 (United States); Liu Weiping, E-mail: wliu@zjut.edu.c [Research Center of Environmental Science, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China)

    2010-05-15

    The increasing release of chiral chemicals into the environment dictates attention to a better understanding of enantioselectivity in their human and ecotoxicological effects. Although enantioselectivity has been considered in many recent studies, there is little effort for discerning the connection between different processes, and as such, our current knowledge about chiral contaminants is rather scattered and incoherent. In this study, we simultaneously evaluated enantioselectivity of two chiral pesticides, lambda-cyhalothrin (LCT) and (Z)-cis-bifenthrin (cis-BF), in immunotoxicity to macrophage cells (RAW264.7), and endocrine disruption activity in human breast carcinoma cell line MCF-7. Analysis of cell proliferation, cell viability, apoptosis, and receptor gene expression showed significant differences between the enantiomers of LCT or cis-BF in estrogenic potential and immunocytotoxicity. The selectivity in these effects consistently followed the same direction, with (-)-LCT or 1S-cis-BF displaying a greater activity than its counterpart. The consistency was attributed to interplaying mechanisms in the closely interacting immune and endocrine systems. The underlying interplays suggest that other chiral xenobiotics may also show a directional enantioselectivity in immunotoxicity and endocrine toxicity. Given that many biological processes are inter-related, enantioselectivity may follow specific patterns that can be revealed via integrative assessments as demonstrated in this study. - Chiral contaminants should consider multiple effects and relate directions of enantioselectivity to their interplaying processes.

  16. Integrative assessment of enantioselectivity in endocrine disruption and immunotoxicity of synthetic pyrethroids

    International Nuclear Information System (INIS)

    Zhao Meirong; Chen Fang; Wang Cui; Zhang Quan; Gan Jianying; Liu Weiping

    2010-01-01

    The increasing release of chiral chemicals into the environment dictates attention to a better understanding of enantioselectivity in their human and ecotoxicological effects. Although enantioselectivity has been considered in many recent studies, there is little effort for discerning the connection between different processes, and as such, our current knowledge about chiral contaminants is rather scattered and incoherent. In this study, we simultaneously evaluated enantioselectivity of two chiral pesticides, lambda-cyhalothrin (LCT) and (Z)-cis-bifenthrin (cis-BF), in immunotoxicity to macrophage cells (RAW264.7), and endocrine disruption activity in human breast carcinoma cell line MCF-7. Analysis of cell proliferation, cell viability, apoptosis, and receptor gene expression showed significant differences between the enantiomers of LCT or cis-BF in estrogenic potential and immunocytotoxicity. The selectivity in these effects consistently followed the same direction, with (-)-LCT or 1S-cis-BF displaying a greater activity than its counterpart. The consistency was attributed to interplaying mechanisms in the closely interacting immune and endocrine systems. The underlying interplays suggest that other chiral xenobiotics may also show a directional enantioselectivity in immunotoxicity and endocrine toxicity. Given that many biological processes are inter-related, enantioselectivity may follow specific patterns that can be revealed via integrative assessments as demonstrated in this study. - Chiral contaminants should consider multiple effects and relate directions of enantioselectivity to their interplaying processes.

  17. Pyrethroids in Southern California coastal sediments.

    Science.gov (United States)

    Lao, Wenjian; Tiefenthaler, Liesl; Greenstein, Darrin J; Maruya, Keith A; Bay, Steven M; Ritter, Kerry; Schiff, Kenneth

    2012-07-01

    Little is known about pyrethroid fate and effects in estuarine and marine environments. In the present study, the extent and magnitude of pyrethroids in coastal embayments of the Southern California Bight (SCB), USA, were assessed. Using a stratified probabilistic design, 155 sediment samples were collected from four embayment habitats (estuaries, marinas, open bays, and ports) and analyzed for eight common-use pyrethroids. Total pyrethroid concentrations ranged from less than 0.5 to 230 µg/kg dry weight (area-weighted mean concentration=5.1 ± 3.1 µg/kg) and were detected in 35% of the total SCB embayment area. Estuaries and marinas had the greatest areal extent of detectable concentrations (up to 65%) and the greatest area-weighted mean concentrations (22.1 ± 26.5 µg/kg). Sites with the greatest pyrethroid concentrations were located near sources of runoff from urban watersheds. Bifenthrin and cyfluthrin were detected in 32 and 15% of all samples, respectively, whereas the other six pyrethroids were detected in ≤ 5% of samples. Permethrin and bifenthrin had the highest concentrations at 132 and 65 µg/kg. Toxic units estimated for the marine amphipod Eohaustorius estuarius ranged from 0 to 5.8, exceeding unity in 9 and 32% of the total and estuary habitat areas, respectively, and were not correlated with mortality, suggesting that other factors (e.g., co-occurring contaminants, reduced bioavailability) may affect the predictive capability using a single test species. Copyright © 2012 SETAC.

  18. Cis-bifenthrin induces immunotoxicity in adolescent male C57BL/6 mice.

    Science.gov (United States)

    Wang, Xia; Gao, Xingli; He, Bingnan; Zhu, Jiawei; Lou, Huihui; Hu, Qinglian; Jin, Yuanxiang; Fu, Zhengwei

    2017-07-01

    Bifenthrin (BF) is an important synthetic pyrethroid. Previous studies have demonstrated that cis-BF exhibits toxic effects on development, the neurological, reproductive and endocrine system. In this study, we evaluated the immunotoxicity caused by cis-BF in adolescent male C57BL/6 mice. Mice were exposed orally to 0, 5, 10, and 20 mg/kg/d for 3 weeks. The results showed that body weight, spleen weight, and splenic cellularity decreased in mice exposed to 20 mg/kg/d cis-BF. Additionally, we found that the mRNA levels of the pro-inflammatory factors IL-1β, IL-6, CXCL-1, and TNF-α, in peritoneal macrophages, the spleen, and the thymus were inhibited in the cis-BF-treated groups. Moreover, MTT assays demonstrated that cis-BF inhibited splenocyte proliferation stimulated by LPS or Con A, as well as the secretion of IFN-γ on Con A stimulation. Collectively, the results of this study suggest that exposure to cis-BF has the potential to induce immunotoxicity in adolescent male C57BL/6 mice. © 2017 Wiley Periodicals, Inc.

  19. Microbial detoxification of bifenthrin by a novel yeast and its potential for contaminated soils treatment.

    Directory of Open Access Journals (Sweden)

    Shaohua Chen

    Full Text Available Bifenthrin is one the most widespread pollutants and has caused potential effect on aquatic life and human health, yet little is known about microbial degradation in contaminated regions. A novel yeast strain ZS-02, isolated from activated sludge and identified as Candida pelliculosa based on morphology, API test and 18S rDNA gene analysis, was found highly effective in degrading bifenthrin over a wide range of temperatures (20-40 °C and pH (5-9. On the basis of response surface methodology (RSM, the optimal degradation conditions were determined to be 32.3 °C and pH 7.2. Under these conditions, the yeast completely metabolized bifenthrin (50 mg · L(-1 within 8 days. This strain utilized bifenthrin as the sole carbon source for growth as well as co-metabolized it in the presence of glucose, and tolerated concentrations as high as 600 mg · L(-1 with a q(max, K(s and K(i of 1.7015 day(-1, 86.2259 mg · L(-1 and 187.2340 mg · L(-1, respectively. The yeast first degraded bifenthrin by hydrolysis of the carboxylester linkage to produce cyclopropanecarboxylic acid and 2-methyl-3-biphenylyl methanol. Subsequently, 2-methyl-3-biphenylyl methanol was further transformed by biphenyl cleavage to form 4-trifluoromethoxy phenol, 2-chloro-6-fluoro benzylalcohol, and 3,5-dimethoxy phenol, resulting in its detoxification. Eventually, no persistent accumulative product was detected by gas chromatopraphy-mass spectrometry (GC-MS analysis. This is the first report of a novel pathway of degradation of bifenthrin by hydrolysis of ester linkage and cleavage of biphenyl in a microorganism. Furthermore, strain ZS-02 degraded a variety of pyrethroids including bifenthrin, cyfluthrin, deltamethrin, fenvalerate, cypermethrin, and fenpropathrin. In different contaminated soils introduced with strain ZS-02, 65-75% of the 50 mg · kg(-1 bifenthrin was eliminated within 10 days, suggesting the yeast could be a promising candidate for remediation of environments affected

  20. In vitro acaricidal activity of ethanolic and aqueous floral extracts of Calendula officinalis against synthetic pyrethroid resistant Rhipicephalus (Boophilus) microplus.

    Science.gov (United States)

    Godara, R; Katoch, R; Yadav, A; Ahanger, R R; Bhutyal, A D S; Verma, P K; Katoch, M; Dutta, S; Nisa, F; Singh, N K

    2015-09-01

    Detection of resistance levels against deltamethrin and cypermethrin in Rhipicephalus (Boophilus) microplus collected from Jammu (India) was carried out using larval packet test (LPT). The results showed the presence of resistance level II and I against deltamethrin and cypermethrin, respectively. Adult immersion test (AIT) and LPT were used to evaluate the in vitro efficacy of ethanolic and aqueous floral extracts of Calendula officinalis against synthetic pyrethroid resistant adults and larvae of R. (B.) microplus. Four concentrations (1.25, 2.5, 5 and 10 %) of each extract with four replications for each concentration were used in both the bioassays. A concentration dependent mortality was observed and it was more marked with ethanolic extract. In AIT, the LC50 values for ethanolic and aqueous extracts were calculated as 9.9 and 12.9 %, respectively. The egg weight of the live ticks treated with different concentrations of the ethanolic and aqueous extracts was significantly lower than that of control ticks; consequently, the reproductive index and the percent inhibition of oviposition values of the treated ticks were reduced. The complete inhibition of hatching was recorded at 10 % of ethanolic extract. The 10 % extracts caused 100 % mortality of larvae after 24 h. In LPT, the LC50 values for ethanolic and aqueous extracts were determined to be 2.6 and 3.2 %, respectively. It can be concluded that the ethanolic extract of C. officinalis had better acaricidal properties against adults and larvae of R. (B.) microplus than the aqueous extract.

  1. EVALUATION OF THE TOXICITY OF SYNTHETIC PYRETHROIDS TO RED SWAMP CRAYFISH (PROCAMBARUS CLARKII, GIRARD 1852 AND COMMON CARP (CYPRINUS CARPIO, L. 1758

    Directory of Open Access Journals (Sweden)

    MOROLLI C.

    2006-01-01

    Full Text Available The acute toxicity of three synthetic pyrethroids (Cypermethrin, Deltamethrin and Cyfluthrin to red swamp crayfish (Procambarus clarkii and the mortality after long-term exposition of young common carp to Deltamethrin were determined in standardized laboratory tests. The aim of this study was to evaluate the possibility of limiting the expansion of crayfish by the use of these compounds and the implications of their use on fish. Red swamp crayfish experienced high sensitivity to pyrethroids as expressed by the LC50-24h: 0.14 μg/l for Cypermethrin, 0.17 μg/l for Cyfluthrin and 0.22 μg/l for Deltamethrin. No mortality was observed in common carp during the long term (24 days exposure test at initial concentration of 22.0 μg/l of Deltamethrin. The concentrations of Deltamethrin in muscle of crayfish and common carp were under the limit of quantification of the gas-chromatographic method in all the tests. The results suggest that synthetic pyrethroids may be suitable to control or to eradicate nuisance populations of red swamp crayfish, in small and limited areas.

  2. In vivo dermal absorption of pyrethroid pesticides in the rat.

    Science.gov (United States)

    The potential for exposure to pyrethroid pesticides has risen recently because of their increased use. The objective of this study was to examine the in vivo dermal absorption of bifenthrin, deltamethrin and permethrin in the rat. Hair on the dorsal side of anesthetized adult m...

  3. Progress and future of pyrethroids.

    Science.gov (United States)

    Katsuda, Yoshio

    2012-01-01

    After the chemical structure of "natural pyrethrins," the insecticidal ingredient of pyrethrum flowers, was elucidated, useful synthetic pyrethroids provided with various characteristics have been developed by organic chemists throughout the world, leading to the advancement of pyrethroid chemistry. Even in pyrethroids with high selective toxicity, a chemical design placing too much importance on efficacy improvements may invite loss of the safety margin. It is strongly hoped that the development of household pyrethroids and their preparations for use in living environments around humans and pets will be achieved in the future by retaining the characteristics of natural pyrethrins.

  4. Occurrence and potential sources of pyrethroid insecticides in stream sediments from seven U.S. metropolitan areas

    Science.gov (United States)

    Kuivila, Kathryn; Hladik, Michelle; Ingersoll, Christopher G.; Kemble, Nile E.; Moran, Patrick W.; Calhoun, Daniel L.; Nowell, Lisa H.; Gilliom, Robert J.

    2012-01-01

    A nationally consistent approach was used to assess the occurrence and potential sources of pyrethroid insecticides in stream bed sediments from seven metropolitan areas across the United States. One or more pyrethroids were detected in almost half of the samples, with bifenthrin detected the most frequently (41%) and in each metropolitan area. Cyhalothrin, cypermethrin, permethrin, and resmethrin were detected much less frequently. Pyrethroid concentrations and Hyalella azteca mortality in 28-d tests were lower than in most urban stream studies. Log-transformed total pyrethroid toxic units (TUs) were significantly correlated with survival and bifenthrin was likely responsible for the majority of the observed toxicity. Sampling sites spanned a wide range of urbanization and log-transformed total pyrethroid concentrations were significantly correlated with urban land use. Dallas/Fort Worth had the highest pyrethroid detection frequency (89%), the greatest number of pyrethroids (4), and some of the highest concentrations. Salt Lake City had a similar percentage of detections but only bifenthrin was detected and at lower concentrations. The variation in pyrethroid concentrations among metropolitan areas suggests regional differences in pyrethroid use and transport processes. This study shows that pyrethroids commonly occur in urban stream sediments and may be contributing to sediment toxicity across the country.

  5. Pyrethroid insecticides in bed sediments from urban and agricultural streams across the United States

    Science.gov (United States)

    Hladik, Michelle; Kuivila, Kathryn

    2012-01-01

    Pyrethroid insecticides are hydrophobic compounds that partition to streambed sediments and have been shown to cause toxicity to non-target organisms; their occurrence is well documented in parts of California, but there have been limited studies in other urban and agricultural areas across the United States. To broaden geographic understanding of pyrethroid distributions, bed sediment samples were collected and analyzed from 36 streams in 25 states, with about 2/3 of the sites in urban areas and 1/3 in agricultural areas. At least one pyrethroid (of the 14 included in the analysis) was detected in 78% of samples. Seven pyrethroids were detected in one or more samples. Bifenthrin was the most frequently detected (58% of samples), followed by permethrin (31%), resmethrin (17%), and cyfluthrin (14%). The other three detected pyrethroids (cyhalothrin, cypermethrin and delta/tralomethrin) were found in two or fewer of the samples. Concentrations ranged from 0.3 to 180 ng g-1 dry weight. The number of pyrethroids detected were higher in the urban samples than in the agricultural samples, but the highest concentrations of individual pyrethroids were split between urban and agricultural sites. The pyrethroids detected in the agricultural areas generally followed use patterns. Predicted toxicity was greater for urban areas and attributed to bifenthrin, cyfluthrin and cypermethrin, while in agricultural areas the toxicity was mainly attributed to bifenthrin.

  6. Pyrethroid insecticides in urban salmon streams of the Pacific Northwest

    Energy Technology Data Exchange (ETDEWEB)

    Weston, D.P., E-mail: dweston@berkeley.edu [Department of Integrative Biology, University of California, 3060 Valley Life Sciences Bldg., Berkeley, CA 94720-3140 (United States); Asbell, A.M., E-mail: aasbell@berkeley.edu [Department of Integrative Biology, University of California, 3060 Valley Life Sciences Bldg., Berkeley, CA 94720-3140 (United States); Hecht, S.A., E-mail: scott.hecht@noaa.gov [NOAA Fisheries, Office of Protected Resources, 510 Desmond Drive S.E., Lacey, WA 98503 (United States); Scholz, N.L., E-mail: nathaniel.scholz@noaa.gov [NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Blvd. E., Seattle, WA 98112 (United States); Lydy, M.J., E-mail: mlydy@siu.edu [Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University, 171 Life Sciences II, Carbondale, IL 62901 (United States)

    2011-10-15

    Urban streams of the Pacific Northwest provide spawning and rearing habitat for a variety of salmon species, and food availability for developing salmon could be adversely affected by pesticide residues in these waterbodies. Sediments from Oregon and Washington streams were sampled to determine if current-use pyrethroid insecticides from residential neighborhoods were reaching aquatic habitats, and if they were at concentrations acutely toxic to sensitive invertebrates. Approximately one-third of the 35 sediment samples contained measurable pyrethroids. Bifenthrin was the pyrethroid of greatest concern with regards to aquatic life toxicity, consistent with prior studies elsewhere. Toxicity to Hyalella azteca and/or Chironomus dilutus was found in two sediment samples at standard testing temperature (23 deg. C), and in one additional sample at a more environmentally realistic temperature (13 deg. C). Given the temperature dependency of pyrethroid toxicity, low temperatures typical of northwest streams can increase the potential for toxicity above that indicated by standard testing protocols. - Highlights: > Salmon-bearing creeks can be adversely impacted by insecticides from urban runoff. > Pyrethroid insecticides were found in one-third of the creeks in Washington and Oregon. > Two creeks contained concentrations acutely lethal to sensitive invertebrates. > Bifenthrin was of greatest concern, though less than in prior studies. > Standard toxicity testing underestimates the ecological risk of pyrethroids. - Pyrethroid insecticides are present in sediments of urban creeks of Oregon and Washington, though less commonly than in studies elsewhere in the U.S.

  7. Enantioselective cytotoxicity of the insecticide bifenthrin on a human amnion epithelial (FL) cell line

    International Nuclear Information System (INIS)

    Liu Huigang; Zhao Meirong; Zhang Cong; Ma Yun; Liu Weiping

    2008-01-01

    Synthetic pyrethroids (SPs) are used in preference to organochlorines and organophosphates due to their high efficiency, low toxicity to mammals, and ready biodegradability. Previous studies reported that enantioselective toxicity of SPs occurs in aquatic toxicity. Several studies have indicated that SPs could lead to oxidative damage in humans or animals which was associated with their toxic effects. Little is known about the differences in the effects of chronic toxicity induced by individual stereoisomers of chiral SPs. The present study was therefore undertaken to evaluate the enantioselectivity in cytotoxicity, genotoxicity caused by bifenthrin (BF) on human amnion epithelial (FL) cell lines and pesticidal activity on target organism. The cell proliferation and cytoflow analysis indicated that 1S-cis-BF presented more toxic effects than 1R-cis-BF above the concentration of 7.5 mg L -1 (p > 0.05). FL cells incubated with 1S-cis-BF exhibited a dose-dependent accumulation of intracellular reactive oxygen species (ROS). In the comet assay, the number of cells with damaged DNA incubated with 1S-cis-BF was more than that with 1R-cis-BF (p 50 values of enantiomer to the target pest on Pieris rapae L. show that 1R-cis-BF was 300 times more active than 1S-cis-BF. These results indicate that the enantioselective toxicity and activity of BF between non-target organism and target organism was reversal. These implications together suggest that assessment of the environmental safety and new pesticides development with chiral centers should consider enantioselectivity

  8. Exposure to bifenthrin causes immunotoxicity and oxidative stress in male mice.

    Science.gov (United States)

    Jin, Yuanxiang; Pan, Xiuhong; Fu, Zhengwei

    2014-09-01

    Bifenthrin (BF) is one of the most commonly used pesticides among the synthetic pyrethroids. The effects of BF exposure on the induction of immunotoxicity and oxidative stress were studied both in adolescent and adult male ICR mice. Both the weights of the spleen and thymus decreased significantly in the adolescent mice when they were treated with 20 mg/kg BF for 3 weeks. We found that the 3-week oral administration of BF during puberty increased the transcriptional levels of the genes TNF and IL2 in the spleen and IL2 as well as IL4 in the thymus. The effect of BF exposure on the induction of oxidative stress was also studied in serum and liver samples. The total antioxidant capacity and activity of superoxide dismutase were altered significantly in the serum of the 20 mg/kg BF-treated adolescent mice, and the activity of glutathione peroxidase (GPX) decreased significantly in the serum of adolescent and adult mice after 3 weeks of oral administration of 20 mg/kg BF. Compared to serum, hepatic GSH content increased significantly in both the adolescent and adult mice exposed to 20 mg/kg BF; hepatic CAT and GPX activities were altered significantly, even in adolescent mice, after treatment with 10 mg/kg BF. Taken together, the results of this study suggest that exposure to BF, especially during puberty, has the potential to induce immunotoxicity accompanied by oxidative stress in male mice. These findings will help in elucidating the mechanism of toxicity induced by BF in mice. Copyright © 2012 Wiley Periodicals, Inc., a Wiley company.

  9. Tissue disposition of bifenthrin in the rat

    Data.gov (United States)

    U.S. Environmental Protection Agency — Tissue disposition of bifenthrin in the rat and oral and intravenous administration. This dataset is associated with the following publication: Hughes , M., D. Ross...

  10. The effect of synthetic pyrethroids on the attachment and host-feeding behaviour in Dermacentor reticulatus females (Ixodida: Amblyommidae).

    Science.gov (United States)

    Buczek, Alicja; Lachowska-Kotowska, Patrycja; Bartosik, Katarzyna

    2015-07-11

    The high competence of D. reticulatus in transmission of tick-borne pathogens prompts investigations of the effect of chemicals used as repellents and acaricides on the behaviour of the tick on the host. Therefore, this paper presents the effect of permethrin and deltamethrin on the attachment and feeding in this tick species. Attachment to rabbit skin of D. reticulatus females sprayed with pyrethroids and the effect of different doses thereof on feeding were assessed at a temperature of 20 ± 3 °C and 50% humidity. The dynamics of attachment of D. reticulatus females varied in a dose-dependent manner after the application of both pyrethroids. Within the first 0.5 h of the experiments, there was an over six-fold and over twelve-fold increase in the number of females attached to host skin after application of permethrin concentrations of 0.3906-0.7812 μg and 1.5625-3.1250 μg/1 specimen, respectively. In the case of deltamethrin, females treated with the dose of 0.0390 μg of the compound were able to attach to host skin only 4 hours after the infestation. The toxic activity of both pyrethroids increased the duration of the feeding period and decreased the body weight of engorged females and the feeding efficiency index. The accelerated attachment of D. reticulatus females caused by sublethal permethrin doses and delayed or inhibited attachment caused by deltamethrin suggest a necessity of careful selection of the type and dose of pyrethroids to protect hosts from tick attacks.

  11. Enantiomeric-selective determination of pyrethroids: application to human samples.

    Science.gov (United States)

    Corcellas, Cayo; Eljarrat, Ethel; Barceló, Damià

    2015-01-01

    Recently, some works point out the bioaccumulation of pyrethroids in humans. Given the chiral properties of pyrethroids, our goal in this work was to develop a gas chromatography (GC)-MS-MS methodology for the enantioselective analysis of six common pyrethroids. For the first time, we separate the enantiomers of bifenthrin, cyhalothrin, cyfluthrin, cypermethrin, permethrin and tetramethrin in a single analysis of less than 75 min and with resolutions greater than 0.58 in all cases. The developed method proved to be reproducible (with relative standard deviations under 3%) and sensitive (with instrumental limits of detection from 4 to 49 fg) enough to evaluate the enantiomeric distribution of these pyrethroids. The developed methodology was applied to commercial insecticides and human breast milk samples. Some potential selective bioaccumulation for cyhalothrin, cyperpermethrin and tetramethrin was described in humans.

  12. Pyrethroid resistance discovered in a major agricultural pest in southern Australia: the redlegged earth mite Halotydeus destructor (Acari: Penthaleidae).

    Science.gov (United States)

    Umina, Paul A

    2007-12-01

    The redlegged earth mite (Halotydeus destructor Tucker) is an important pest of field crops and pastures. Control of this pest relies heavily on chemicals, with few genuine alternatives presently available. Pesticide responses of H. destructor from the field with reported chemical control failures were compared with mites from susceptible 'control' populations. Toxicology bioassays were conducted on adult mites across multiple generations. Very high levels of resistance to two synthetic pyrethroids, bifenthrin and alpha-cypermethrin, were detected in this species for the first time. For bifenthrin, LC(50) estimates showed a difference in resistance of greater than 240 000-fold. Resistance to alpha-cypermethrin was almost 60 000-fold. This resistance was shown to be heritable, persisting after several generations of culturing. There was no evidence that resistance to organophosphorus chemicals had evolved, which is likely to be a direct consequence of the history of chemical applications these mites have experienced. These results highlight the need for more judicious management decisions in order to control pest species in a sustainable manner. The implications of these findings in regard to the management and future research of the redlegged earth mite are discussed. Copyright (c) 2007 Society of Chemical Industry.

  13. Determination of Pyrethroids through Liquid-Liquid Extraction and GC-ECD

    Science.gov (United States)

    Ding, B.

    2010-12-01

    Storm water samples from various locations in San Diego Creek and Newport Bay watershed, southern California, were taken to study the occurrence and fate of pyrethroids. This study focused on four commonly used pyrethroids: bifenthrin, cypermethrin, permethrin, and fenpropathrin. Since the ban of DDT, usage of pyrethroids became an effective second choice. However, pyrethroids are extremely toxic to fish and aquatic organisms. They can pass through secondary wastewater treatment system, causing the final effluent to be in lethal doses to aquatic invertebrates and some insects such as mayflies. Hence, it is necessary to monitor the amount of pyrethroid concentration in storm water. As a part of this study, I attended the RISE internship program at Stanford University in this summer. In the seven weeks, I learned liquid-liquid extraction, water-bath evaporation, nitrogen evaporation, and gas chromatography-electron capture detector techniques to extract and detect the pyrethroid residues in the water sample.

  14. 76 FR 82296 - Pyrethrins/Pyrethroid Cumulative Risk Assessment; Extension of Comment Period

    Science.gov (United States)

    2011-12-30

    ... pyrethrins and synthetic pyrethroid pesticides (often collectively called ``the pyrethroids'') and opened a... cumulative risk assessment for the pyrethroids. Based on this assessment, the EPA concluded that the..., Pyrethrins and Pyrethroids. Dated: December 21, 2011. Richard P. Keigwin, Jr., Director, Pesticide Re...

  15. Residential runoff as a source of pyrethroid pesticides to urban creeks

    Energy Technology Data Exchange (ETDEWEB)

    Weston, D.P. [Department of Integrative Biology, University of California, 3060 Valley Life Sciences Building, Berkeley, CA 94720-3140 (United States)], E-mail: dweston@berkeley.edu; Holmes, R.W. [Water Branch, California Department of Fish and Game, 830 S Street, Sacramento, CA 95811 (United States)], E-mail: rholmes@dfg.ca.gov; Lydy, M.J. [Fisheries and Illinois Aquaculture Center, Department of Zoology, Southern Illinois University, 171 Life Sciences II, Carbondale, IL 62901 (United States)], E-mail: mlydy@siu.edu

    2009-01-15

    Pyrethroid pesticides occur in urban creek sediments at concentrations acutely toxic to sensitive aquatic life. To better understand the source of these residues, runoff from residential neighborhoods around Sacramento, California was monitored over the course of a year. Pyrethroids were present in every sample. Bifenthrin, found at up to 73 ng/L in the water and 1211 ng/g on suspended sediment, was the pyrethroid of greatest toxicological concern, with cypermethrin and cyfluthrin of secondary concern. The bifenthrin could have originated either from use by consumers or professional pest controllers, though the seasonal pattern of discharge from the drain was more consistent with professional use as the dominant source. Stormwater runoff was more important than dry season irrigation runoff in transporting pyrethroids to urban creeks. A single intense storm was capable of discharging as much bifenthrin to an urban creek in 3 h as that discharged over 6 months of irrigation runoff. - Pyrethroid insecticides regularly detected in residential runoff at toxicologically significant concentrations.

  16. Establishment of Diagnostic Doses of Five Pyrethroids for Monitoring Physiological Resistance in Aedes Albopictus in Thailand.

    Science.gov (United States)

    Thanispong, Kanutcharee; Sathantriphop, Sunaiyana; Malaithong, Naritsara; Bangs, Michael J; Chareonviriyaphap, Theeraphap

    2015-12-01

    Monitoring insecticide resistance of Aedes albopictus is required for implementing effective dengue and chikungunya vector control in Thailand. The World Health Organization standard susceptibility test for adult mosquitoes was used to determine the baseline susceptibility of a pyrethroid-susceptible laboratory strain of Ae. albopictus to 5 different pyrethroids (deltamethrin, permethrin, bifenthrin, cypermethrin, and α-cypermethrin). Subsequently, the respective established diagnostic doses (0.026% deltamethrin, 1.024% permethrin, 0.570% bifenthrin, 0.237% cypermethrin, and 0.035% α-cypermethrin) were used to test field-collected Ae. albopictus from Rayong, Koh Chang, and Pong Nom Ron. As expected, the laboratory strain was completely susceptible to all pyrethroid insecticides at the established concentrations. Rayong mosquitoes were found to be highly susceptible to bifenthrin, cypermethrin, and α-cypermethrin. Koh Chang mosquitoes were susceptible to only deltamethrin and permethrin. Pong Nom Ron mosquitoes were resistant to all pyrethroids tested. Routine assessment of these baseline results should guide future resistance monitoring to pyrethroid insecticides in Ae. albopictus in Thailand.

  17. Syntetiske pyrethroider i private hjem

    DEFF Research Database (Denmark)

    Jensen, Karl-Martin Vagn; Fomsgaard, Inge S.; Kilpinen, Ole Østerlund

    2015-01-01

    A number of different methods are tested to elucidate the accumulation of synthetic pyrethroids in private homes. When the target pest is resistant, there is a potential risk that persistent synthetic pyrethroids accumulate because of repeated treatments. The highest residue found was 8260 µg lam...... lambda-cyhalothrin in a vacuum-cleaner sample (vacuumed for 10 minutes) and 1252 µg lambda-cyhalothrin in a “cotton sock dosimeter” sample. Similar data for deltamethrin was 805 µg in a vacuum-cleaner sample and 806 µg in a “cotton sock dosimeter” sample....

  18. Effects of salinity acclimation on the endocrine disruption and acute toxicity of bifenthrin in freshwater and euryhaline strains of Oncorhynchus mykiss.

    Science.gov (United States)

    Riar, Navneet; Crago, Jordan; Jiang, Weiying; Maryoung, Lindley A; Gan, Jay; Schlenk, Daniel

    2013-12-01

    The pyrethroid insecticide bifenthrin is frequently detected at ng/L concentrations in tributaries of the San Francisco Bay Delta. The estuary is also experiencing increasing salinity through climate change and water redirection. To evaluate the impacts of hypersaline conditions on bifenthrin toxicity in anadromous salmonids of the San Francisco Bay Delta (CA, USA), a 14-d laboratory exposure was performed using 2 strains of Oncorhynchus mykiss (rainbow trout and steelhead) acclimated to freshwater and to 8 g/L and 17 g/L salinity. The fish were then exposed to nominal concentrations of 0 µg/L, 0.1 µg/L, and 1.5 µg/L bifenthrin. Rainbow trout exhibited significant mortality following exposure to 1.5 µg/L (1.07 ± 0.35 µg/L measured) bifenthrin in freshwater. Elevated levels of Na⁺ /K⁺ adenosine triphosphatase α1A mRNA subunit expression was observed in the gill of rainbow trout acclimated to hypersaline conditions relative to freshwater animals. No significant difference was noted in Na⁺ /K⁺ adenosine triphosphatase subunit levels in brains of either strain in freshwater or hypersaline conditions. Likewise, significant differences were not observed in plasma vitellogenin or steroid hormone concentrations in either strain whether maintained in freshwater or saltwater. Saltwater acclimation significantly reduced nicotinamide adenine dinucleotide phosphate-catalyzed biotransformation of bifenthrin in liver microsomes of rainbow trout but not of steelhead. The present study showed that, relative to steelhead, rainbow trout have different responses to bifenthrin acute toxicity as well as different rates of hepatic bifenthrin biotransformation and regulation of Na⁺ /K⁺ adenosine triphosphatase subunits in gills. These data indicate that significant differences exist between the strains and that animal life history may have important effects on the susceptibility of each strain to environmental contaminants. © 2013 SETAC.

  19. Effects of Piperonyl Butoxide and Tetramethrin Combinations on Biological Activities of Selected Synthetic Pyrethroid Insecticides against Different Housefly (Musca domestica L., Diptera: Muscidae Populations

    Directory of Open Access Journals (Sweden)

    G. Cakir

    2008-01-01

    Full Text Available Piperonyl butoxide (PBO, a methylenedioxyphenyl compound, is primarily used as a synergist in combination with space spray, residual and admixture products for the control of insect pests in or around domestic and commercial premises, especially food preparation areas. Also, tetramethrin is known as a knockdown agent on target organism and it is generally used with piperonyl butoxide. In this study, effects of piperonyl butoxide and tetramethrin combinations on biological activities of synthetic pyrethroids, cypermethrin, deltamethrin, and permethrin against different housefly (Musca domestica Linnaeus, 1758 populations were evaluated. In addition, the biological efficiency of the insecticides used in the study, insecticide + PBO and insecticide + PBO + tetramethrin combinations, against the WHO standard sensitive housefly population and housefly populations collected from different parts of Turkey were compared. Results showed that PBO extensively promoted the ratio of knockdown and killing effect values of the insecticides. The results also indicated that PBO and PBO + tetramethrin combinations moderately reduced the knockdown effect times of all formulation in all housefly populations. The knockdown effect times were more decreased by insecticide + PBO + tetramethrin combinations than insecticides that are used alone and insecticide + PBO combinations.

  20. Binary combinations of organophosphorus and synthetic pyrethroids are more potent acetylcholinesterase inhibitors than organophosphorus and carbamate mixtures: An in vitro assessment.

    Science.gov (United States)

    Arora, Sumitra; Balotra, Sahil; Pandey, Gunjan; Kumar, Anu

    2017-02-15

    Anticholinesterase insecticides such as organophosphorous (OP) and carbamates pesticides (CB); and synthetic pyrethroids (SP) pesticides commonly co-occur in the environment. This raises the possibility of antagonistic, additive, or synergistic neurotoxicity in exposed organisms. Acetylcholinesterase (AChE) inhibition has been demonstrated to be useful as a biomarker for exposure to OP and CBs in many environments. This study investigated the response of housefly (Musca domestica) head AChE (HF-AChE) exposed to five OPs; chlorpyrifos (CPF), malathion (MLT), triazophos (TRZ), monocrotophos (MCP) and profenofos (PRF) and two CBs; carbaryl (CRB) and carbofuran (CBF) as individual compounds and as binary mixtures of OPs and CBs under in vitro conditions. In addition, the selected OPs and CBs were evaluated for their toxicity in binary combinations with two SPs; deltamethrin (DLT) and cypermethrin (CYP) at fixed concentrations of 0.1 and 10μg/L. The toxicological interaction of five OPs with two CBs pesticides was evaluated under oxidised and un-oxidised conditions using a toxic unit (TU) approach and a concentration addition (CA) model. Pyrethroid combinations were assessed only under oxidised conditions. Since OPs and CBs act by a similar mechanism of inhibition of AChE, a dose additive effect was expected, but not conclusively found. TRZ with either CBF or CRB exhibited synergism under oxidised and un-oxidised conditions but the degree of synergism was stronger under un-oxidised conditions. Additivity was exhibited by CBF+MCP, CRB+MCP, CRB+MLT and CBF+MCP under un-oxidised conditions and CRB+MCP and CRB+CPF under oxidised conditions. Pyrethorids in combination with OPs (TRZ, MLT and CPF) were highly synergistic. In the present study, we used pure housefly head AChE without any interference of monooxygenase and/or esterase enzyme activities. Therefore these other enzymes were not producing the observed deviations from concentration-addition in the binary combinations

  1. Pyrethrum flowers and pyrethroid insecticides.

    OpenAIRE

    Casida, J E

    1980-01-01

    The natural pyrethrins from the daisy-like flower, Tanacetum or Chrysanthemum cinerariifolium, are nonpersistent insecticides of low toxicity to mammals. Synthetic analogs or pyrethroids, evolved from the natural compounds by successive isosteric modifications, are more potent and stable and are the newest important class of crop protection chemicals. They retain many of the favorable properties of the pyrethrins.

  2. Suspended particles only marginally reduce pyrethroid toxicity to the freshwater invertebrate Gammarus pulex (L.) during pulse exposure.

    Science.gov (United States)

    Rasmussen, Jes Jessen; Cedergreen, Nina; Kronvang, Brian; Andersen, Maj-Britt Bjergager; Nørum, Ulrik; Kretschmann, Andreas; Strobel, Bjarne Westergaard; Hansen, Hans Christian Bruun

    2016-04-01

    Current ecotoxicological research on particle-associated pyrethroids in freshwater systems focuses almost exclusively on sediment-exposure scenarios and sediment-dwelling macroinvertebrates. We studied how suspended particles influence acute effects of lambda-cyhalothrin and bifenthrin on the epibenthic freshwater amphipod Gammarus pulex (L.) using brief pulse exposures followed by a 144 h post exposure recovery phase. Humic acid (HA) and the clay mineral montmorillonite (MM) were used as model sorbents in environmentally realistic concentrations (5, 25 and 125 mg L(-1)). Mortality of G. pulex was recorded during the post exposure recovery phase and locomotor behavior was measured during exposure to lambda-cyhalothrin. We found that HA in concentrations ≥25 mg L(-1) adsorbed the majority of pyrethroids but only reduced mortality of G. pulex up to a factor of four compared to pyrethroid-only treatments. MM suspensions adsorbed a variable fraction of pyrethroids (10% for bifenthrin and 70% for lambda-cyhalothrin) but did not significantly change the concentration-response relationship compared to pure pyrethroid treatments. Behavioral responses and immobilisation rate of G. pulex were reduced in the presence of HA, whereas behavioral responses and immobilisation rate were increased in the presence of MM. This indicates that G. pulex was capable of sensing the bioavailable fraction of lambda-cyhalothrin. Our results imply that suspended particles reduce to only a limited extent the toxicity of pyrethroids to G. pulex and that passive uptake of pyrethroids can be significant even when pyrethroids are adsorbed to suspended particles.

  3. Evaluation of Bifenthrin and Deltamethrin Barrier Sprays for Mosquito Control in Eastern North Carolina.

    Science.gov (United States)

    Richards, Stephanie L; Volkan, Josh K; Balanay, Jo Anne G; Vandock, Kurt

    2017-11-07

    Mosquitoes are a nuisance and potentially transmit pathogens causing numerous diseases worldwide. Homeowners and others may hire private companies to alleviate mosquito-related issues. Here, two pyrethroids (Suspend Polyzone [deltamethrin] and Bifen Insecticide/Termiticide [bifenthrin]) were evaluated on properties in North Carolina for 23 wk from 18 May through 19 October 2015. Properties were treated using backpack mist blowers every 21 d. At 17 fixed sampling locations, Centers for Disease Control and Prevention carbon dioxide-baited traps were deployed overnight once/week for the duration of the experiment. Oviposition traps were deployed weekly at the same locations. Differences were observed in mosquito abundance between neighborhoods, treatments, and weeks and differences varied between species. Mosquito abundance was generally significantly higher in traps placed on control properties (no insecticide) compared to traps placed on treatment properties. Bifenthrin and deltamethrin showed differences from each other in efficacy, but this varied between neighborhoods and species. Future studies could test the efficacy of barrier sprays at different application frequencies and/or in conjunction with weather monitoring. Coupled with regular mosquito surveillance and using integrated pest management principles, barrier sprays can be an effective tool for suppression of mosquito populations. © The Authors 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.

  4. Predicted transport of pyrethroid insecticides from an urban landscape to surface water.

    Science.gov (United States)

    Jorgenson, Brant; Fleishman, Erica; Macneale, Kate H; Schlenk, Daniel; Scholz, Nathaniel L; Spromberg, Julann A; Werner, Inge; Weston, Donald P; Xiao, Qingfu; Young, Thomas M; Zhang, Minghua

    2013-11-01

    The authors developed a simple screening-level model of exposure of aquatic species to pyrethroid insecticides for the lower American River watershed (California, USA). The model incorporated both empirically derived washoff functions based on existing, small-scale precipitation simulations and empirical data on pyrethroid insecticide use and watershed properties for Sacramento County, California, USA. The authors calibrated the model to in-stream monitoring data and used it to predict daily river pyrethroid concentration from 1995 through 2010. The model predicted a marked increase in pyrethroid toxic units starting in 2000, coincident with an observed watershed-wide increase in pyrethroid use. After 2000, approximately 70% of the predicted total toxic unit exposure in the watershed was associated with the pyrethroids bifenthrin and cyfluthrin. Pyrethroid applications for aboveground structural pest control on the basis of suspension concentrate categorized product formulations accounted for greater than 97% of the predicted total toxic unit exposure. Projected application of mitigation strategies, such as curtailment of structural perimeter band and barrier treatments as recently adopted by the California Department of Pesticide Regulation, reduced predicted total toxic unit exposure by 84%. The model also predicted that similar reductions in surface-water concentrations of pyrethroids could be achieved through a switch from suspension concentrate-categorized products to emulsifiable concentrate-categorized products without restrictions on current-use practice. Even with these mitigation actions, the predicted concentration of some pyrethroids would continue to exceed chronic aquatic life criteria. © 2013 SETAC.

  5. Effects of metals on enantioselective toxicity and biotransformation of cis-bifenthrin in zebrafish.

    Science.gov (United States)

    Yang, Ye; Ji, Dapeng; Huang, Xin; Zhang, Jianyun; Liu, Jing

    2017-08-01

    Co-occurrence of pyrethroids and metals in watersheds previously has been reported to pose great risk to aquatic species. Pyrethroids are a class of chiral insecticides that have been shown to have enantioselective toxicity and biotransformation. However, the influence of metals on enantioselectivity of pyrethroids has not yet been evaluated. In the present study, the effects of cadmium (Cd), copper (Cu), and lead (Pb) on the enantioselective toxicity and metabolism of cis-bifenthrin (cis-BF) were investigated in zebrafish at environmentally relevant concentrations. The addition of Cd, Cu, or Pb significantly increased the mortality of zebrafish in racemate and R-enantiomer of cis-BF-treated groups. In rac-cis-BF- or 1R-cis-BF-treated groups, the addition of Cd, Cu, or Pb caused a decrease in enantiomeric fraction (EF) and an increased ratio of R-enantiomer residues in zebrafish. In 1S-cis-BF-treated groups, coexposure to Cd led to a lower EF and decreased residue levels of S-enantiomer. In addition, coexposure to the 3 metals resulted in different biodegradation characteristics of each enantiomer accompanied with differential changes in the expression of cytochrome P450 (CYP)1, CYP2, and CYP3 genes, which might be responsible for the enantioselective biodegradation of cis-BF in zebrafish. These results suggest that the influence of coexistent metals should be considered in the ecological risk assessment of chiral pyrethroids in aquatic environments. Environ Toxicol Chem 2017;36:2139-2146. © 2017 SETAC. © 2017 SETAC.

  6. Global occurrence of pyrethroid insecticides in sediment and the associated toxicological effects on benthic invertebrates: An overview.

    Science.gov (United States)

    Li, Huizhen; Cheng, Fei; Wei, Yanli; Lydy, Michael J; You, Jing

    2017-02-15

    Pyrethroids are the third most applied group of insecticides worldwide and are extensively used in agricultural and non-agricultural applications. Pyrethroids exhibit low toxicity to mammals, but have extremely high toxicity to fish and non-target invertebrates. Their high hydrophobicity, along with pseudo-persistence due to continuous input, indicates that pyrethroids will accumulate in sediment, pose long-term exposure concerns to benthic invertebrates and ultimately cause significant risk to benthic communities and aquatic ecosystems. The current review synthesizes the reported sediment concentrations of pyrethroids and associated toxicity to benthic invertebrates on a global scale. Geographically, the most studied area was North America, followed by Asia, Europe, Australia and Africa. Pyrethroids were frequently detected in both agricultural and urban sediments, and bifenthrin and cypermethrin were identified as the main contributors to toxicity in benthic invertebrates. Simulated hazard quotients (HQ) for sediment-associated pyrethroids to benthic organisms ranged from 10.5±31.1 (bifenthrin) to 41.7±204 (cypermethrin), suggesting significant risk. The current study has provided evidence that pyrethroids are not only commonly detected in the aquatic environment, but also can cause toxic effects to benthic invertebrates, and calls for better development of accurate sediment quality criteria and effective ecological risk assessment methods for this emerging class of insecticides. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Fenpropathrin biodegradation pathway in Bacillus sp. DG-02 and its potential for bioremediation of pyrethroid-contaminated soils.

    Science.gov (United States)

    Chen, Shaohua; Chang, Changqing; Deng, Yinyue; An, Shuwen; Dong, Yi Hu; Zhou, Jianuan; Hu, Meiying; Zhong, Guohua; Zhang, Lian-Hui

    2014-03-12

    The widely used insecticide fenpropathrin in agriculture has become a public concern because of its heavy environmental contamination and toxic effects on mammals, yet little is known about the kinetic and metabolic behaviors of this pesticide. This study reports the degradation kinetics and metabolic pathway of fenpropathrin in Bacillus sp. DG-02, previously isolated from the pyrethroid-manufacturing wastewater treatment system. Up to 93.3% of 50 mg L(-1) fenpropathrin was degraded by Bacillus sp. DG-02 within 72 h, and the degradation rate parameters qmax, Ks, and Ki were determined to be 0.05 h(-1), 9.0 mg L(-1), and 694.8 mg L(-1), respectively. Analysis of the degradation products by gas chromatography-mass spectrometry led to identification of seven metabolites of fenpropathrin, which suggest that fenpropathrin could be degraded first by cleavage of its carboxylester linkage and diaryl bond, followed by degradation of the aromatic ring and subsequent metabolism. In addition to degradation of fenpropathrin, this strain was also found to be capable of degrading a wide range of synthetic pyrethroids including deltamethrin, λ-cyhalothrin, β-cypermethrin, β-cyfluthrin, bifenthrin, and permethrin, which are also widely used insecticides with environmental contamination problems with the degradation process following the first-order kinetic model. Bioaugmentation of fenpropathrin-contaminated soils with strain DG-02 significantly enhanced the disappearance rate of fenpropathrin, and its half-life was sharply reduced in the soils. Taken together, these results depict the biodegradation mechanisms of fenpropathrin and also highlight the promising potentials of Bacillus sp. DG-02 in bioremediation of pyrethroid-contaminated soils.

  8. [Health effects of pyrethrins and pyrethroids].

    Science.gov (United States)

    Macan, Jelena; Varnai, Veda Marija; Turk, Rajka

    2006-06-01

    Pyrethrins, natural extracts of Chrysanthemum cinerariaefolium and Chrysanthemum cocineum flowers, and pyrethroids, synthetic analogues and derivatives of pyrethrins, are powerful insecticides. They are widely used in households and insect control in pets or livestock, in textiles such as carpets, wallpapers, furniture and clothes, as well as in agriculture, forestry and public health services. This article brings a list of pyrethrin and pyrethroid insecticides registered for use in plant protection in Croatia. Pyrethrins and pyrethroids can enter the organism by ingestion (accidental or suicidal ingestion or in food), by inhalation and/or by skin contact. Although these pesticides pose a relatively low risk to mammals due to rapid metabolism with no significant accumulation, they can induce adverse health effects, more often in acute poisoning, but also due to chronic exposure. The primary target of pyrethrin and pyrethroid toxicity is the nervous system, since they act directly on the sodium channels of nerve cell axons, leading to hyperexcitation. Another important toxicological mechanism is allergenicity, which is more pronounced with pyrethrins than with synthetic pyrethroids. Because there is no antidote for pyrethrin and pyrethroid poisoning, treatment is symptomatic and supportive. The article discusses the measures for poisoning prevention and alleviation of exposure to pyrethrins and pyrethroids in occupational settings and in general population.

  9. Assessing the occurrence and distribution of pyrethroids in water and suspended sediments

    Science.gov (United States)

    Hladik, M.L.; Kuivila, K.M.

    2009-01-01

    The distribution of pyrethroid insecticides in the environment was assessed by separately measuring concentrations in the dissolved and suspended sediment phases of surface water samples. Filtered water was extracted by HLB solid-phase extraction cartridges, while the sediment on the filter was sonicated and cleaned up using carbon and aluminum cartridges. Detection limits for the 13 pyrethroids analyzed by gas chromatography-tandem mass spectrometry were 0.5 to 1 ng L-1 for water and 2 to 6 ng g for the suspended sediments. Seven pyrethroids were detected in six water samples collected from either urban or agricultural creeks, with bifenthrin detected the most frequently and at the highest concentrations. In spiked water samples and field samples, the majority of the pyrethroids were associated with the suspended sediments.

  10. Pyrethroid-Degrading Microorganisms and Their Potential for the Bioremediation of Contaminated Soils: A Review

    Directory of Open Access Journals (Sweden)

    Mariusz Sebastian Cycoń

    2016-09-01

    Full Text Available Pyrethroid insecticides have been used to control pests in agriculture, forestry, horticulture, public health and for indoor home use for more than 20 years. Because pyrethroids were considered to be a safer alternative to organophosphate pesticides (OPs, their applications significantly increased when the use of OPs was banned or limited. Although pyrethroids have agricultural benefits, their widespread and continuous use is a major problem as they pollute the terrestrial and aquatic environments and affect non-target organisms. Since pyrethroids are not degraded immediately after application and because their residues are detected in soils, there is an urgent need to remediate pyrethroid-polluted environments. Various remediation technologies have been developed for this purpose; however, bioremediation, which involves bioaugmentation and/or biostimulation and is a cost-effective and eco-friendly approach, has emerged as the most advantageous method for cleaning-up pesticide-contaminated soils. This review presents an overview of the microorganisms that have been isolated from pyrethroid-polluted sites, characterized and applied for the degradation of pyrethroids in liquid and soil media. The paper is focused on the microbial degradation of the pyrethroids that have been most commonly used for many years such as allethrin, bifenthrin, cyfluthrin, cyhalothrin, cypermethrin, deltamethrin, fenpropathrin, fenvalerate and permethrin. Special attention is given to the bacterial strains from the genera Achromobacter, Acidomonas, Bacillus, Brevibacterium, Catellibacterium, Clostridium, Lysinibacillus, Micrococcus, Ochrobactrum, Pseudomonas, Serratia, Sphingobium, Streptomyces and the fungal strains from the genera Aspergillus, Candida, Cladosporium and Trichoderma, which are characterized by their ability to degrade various pyrethroids. Moreover, the current knowledge on the degradation pathways of pyrethroids, the enzymes that are involved in the

  11. Mechanisms of Pyrethroid Insecticide-Induced Stimulation of Calcium Influx in Neocortical Neurons

    Science.gov (United States)

    Cao, Zhengyu; Shafer, Timothy J.

    2011-01-01

    Pyrethroid insecticides bind to voltage-gated sodium channels (VGSCs) and modify their gating kinetics, thereby disrupting neuronal function. Pyrethroids have also been reported to alter the function of other channel types, including activation of voltage-gated calcium channels. Therefore, the present study compared the ability of 11 structurally diverse pyrethroids to evoke Ca2+ influx in primary cultures of mouse neocortical neurons. Nine pyrethroids (tefluthrin, deltamethrin, λ-cyhalothrin, β-cyfluthrin, esfenvalerate, S-bioallethrin, fenpropathrin, cypermethrin, and bifenthrin) produced concentration-dependent elevations in intracellular calcium concentration ([Ca2+]i) in neocortical neurons. Permethrin and resmethrin were without effect on [Ca2+]i. These pyrethroids displayed a range of efficacies on Ca2+ influx; however, the EC50 values for active pyrethroids all were within one order of magnitude. Tetrodotoxin blocked increases in [Ca2+]i caused by all nine active pyrethroids, indicating that the effects depended on VGSC activation. The pathways for deltamethrin- and tefluthrin-induced Ca2+ influx include N-methyl-d-aspartic acid receptors, L-type Ca2+ channels, and reverse mode of operation of the Na+/Ca2+ exchanger inasmuch as antagonists of these sites blocked deltamethrin-induced Ca2+ influx. These data demonstrate that pyrethroids stimulate Ca2+ entry into neurons subsequent to their actions on VGSCs. PMID:20881019

  12. 76 FR 69726 - Pyrethrins/Pyrethroid Cumulative Risk Assessment; Notice of Availability

    Science.gov (United States)

    2011-11-09

    ... called the `pyrethroids') and opens a public comment period on this document and other supporting... pesticidal uses for the pyrethroids. Based on this assessment, EPA has concluded that the cumulative risks... Synthetic Pyrethroids,'' which is available in the docket EPA-HQ-OPP-2011-0746. List of Subjects...

  13. Pyrethroid and carbamate resistance in Australian Helicoverpa armigera (Lepidoptera: Noctuidae) from 2008 to 2015: what has changed since the introduction of Bt cotton?

    Science.gov (United States)

    Bird, L J

    2018-01-23

    Pyrethroid and carbamate resistance was evaluated in Helicoverpa armigera from 2008 to 2015. Insects were collected as eggs primarily from cultivated hosts in the major cropping areas of New South Wales and Queensland, Australia. Larvae reared from eggs were tested for resistance to fenvalerate, bifenthrin or methomyl in the F 0 generation using a topical application of a discriminating dose of insecticide. In 2008-2009, resistance to fenvalerate was 71% and no resistance to bifenthrin was recorded. In the following two seasons, resistance to pyrethroids was relatively stable with fenvalerate resistance ranging from 63% to 67% and bifenthrin resistance ranging from 5.6% and 6.4% in 2009-2010 and 2010-2011, respectively. However, in 2011-2012, pyrethroid resistance had increased to 91% and 36% for fenvalerate and bifenthrin, respectively. Resistance remained above 90% for fenvalerate and above 35% for bifenthrin in the following three seasons from 2012 to 2015. In 2008-2009, methomyl resistance was 33% and declined to 22% and 15% in 2009-2010 and 2010-2011, respectively. Methomyl resistance remained at moderate levels from 2011-12 to 2014-15, ranging from 21% to 40%. Factors that influenced selection pressure of pyrethroid and carbamate insecticides and impacted resistance frequency in H. armigera may have been associated with changes in the composition of the cropping landscape. The rapid expansion of the pulse industry and the commensurate increased use of insecticide may have played a role in reselection of high-level pyrethroid resistance, and highlights the need for an urgent and strategic response to insecticide resistance management in the Australian grains industry.

  14. Additivity of Pyrethroid Actions on Sodium Influx in Cerebrocortical Neurons in Primary Culture

    Science.gov (United States)

    Cao, Zhengyu; Shafer, Timothy J.; Crofton, Kevin M.; Gennings, Chris

    2011-01-01

    Background: Pyrethroid insecticides bind to voltage-gated sodium channels and modify their gating kinetics, thereby disrupting neuronal function. Although previous work has tested the additivity of pyrethroids in vivo, this has not been assessed directly at the primary molecular target using a functional measure. Objectives: We investigated the potency and efficacy of 11 structurally diverse food-use pyrethroids to evoke sodium (Na+) influx in neurons and tested the hypothesis of dose additivity for a mixture of these same 11 compounds. Methods: We determined pyrethroid-induced increases in Na+ influx in primary cultures of cerebrocortical neurons using the Na+-sensitive dye sodium-binding benzofuran isophthalate (SBFI). Concentration-dependent responses for 11 pyrethroids were determined, and the response to dilutions of a mixture of all 11 compounds at an equimolar mixing ratio was assessed. Additivity was tested assuming a dose-additive model. Results: Seven pyrethroids produced concentration-dependent, tetrodotoxin-sensitive Na+ influx. The rank order of potency was deltamethrin > S-bioallethrin > β-cyfluthrin > λ-cyhalothrin > esfenvalerate > tefluthrin > fenpropathrin. Cypermethrin and bifenthrin produced modest increases in Na+ influx, whereas permethrin and resmethrin were inactive. When all 11 pyrethroids were present at an equimolar mixing ratio, their actions on Na+ influx were consistent with a dose-additive model. Conclusions: These data provide in vitro relative potency and efficacy measurements for 7 pyrethroid compounds in intact mammalian neurons. Despite differences in individual compound potencies, we found the action of a mixture of all 11 pyrethroids to be additive when we used an appropriate statistical model. These results are consistent with a previous report of the additivity of pyrethroids in vivo. PMID:21665567

  15. Pyrethroid pesticide residues in the global environment: An overview.

    Science.gov (United States)

    Tang, Wangxin; Wang, Di; Wang, Jiaqi; Wu, Zhengwen; Li, Lingyu; Huang, Mingli; Xu, Shaohui; Yan, Dongyun

    2018-01-01

    Pyrethroids are synthetic organic insecticides with low mammalian toxicity that are widely used in both rural and urban areas worldwide. After entering the natural environment, pyrethroids circulate among the three phases of solid, liquid, and gas and enter organisms through food chains, resulting in substantial health risks. This review summarized the available studies on pyrethroid residues since 1986 in different media at the global scale and indicated that pyrethroids have been widely detected in a range of environments (including soils, water, sediments, and indoors) and in organisms. The concentrations and detection rates of agricultural pyrethroids, which always contain α-cyanogroup (α-CN), such as cypermethrin and fenvalerate, decline in the order of crops > sediments > soils > water. Urban pyrethroids (not contain α-CN), such as permethrin, have been detected at high levels in the indoor environment, and 3-phenoxybenzoic acid, a common pyrethroid metabolite in human urine, is frequently detected in the human body. Pyrethroid pesticides accumulate in sediments, which are a source of pyrethroid residues in aquatic products. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Pyrethroids in human breast milk: occurrence and nursing daily intake estimation.

    Science.gov (United States)

    Corcellas, Cayo; Feo, Maria Luisa; Torres, Joao Paulo; Malm, Olaf; Ocampo-Duque, William; Eljarrat, Ethel; Barceló, Damià

    2012-10-15

    There is an assumption that pyrethroid pesticides are converted to non-toxic metabolites by hydrolysis in mammals. However, some recent works have shown their bioaccumulation in human breast milk collected in areas where pyrethroids have been widely used for agriculture or malaria control. In this work, thirteen pyrethroids have been studied in human breast milk samples coming from areas without pyrethroid use for malaria control, such as Brazil, Colombia and Spain. The concentrations of pyrethroids ranged from 1.45 to 24.2 ng g⁻¹ lw. Cypermethrin, λ-cyhalothrin, permethrin and esfenvalerate/fenvalerate were present in all the studied samples. The composition of pyrethroid mixture depended on the country of origin of the samples, bifenthrin being the most abundant in Brazilian samples, λ-cyhalothrin in Colombian and permethrin in Spanish ones. When the pyrethroid concentrations were confronted against the number of gestations, an exponential decay was observed. Moreover, a time trend study was carried out in Brazil, where additional archived pool samples were analyzed, corresponding to years when pyrethroids were applied for dengue epidemic control. In these cases, total pyrethroid levels reached up to 128 ng g⁻¹ lw, and concentrations decreased when massive use was not allowed. Finally, daily intake estimation of nursing infants was calculated in each country and compared to acceptable WHO levels. The estimated daily intakes for nursing infants were always below the acceptable daily intake levels, nevertheless in certain samples the detected concentrations were very close to the maximum acceptable levels. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Distribution and persistence of pyrethroids in runoff sediments.

    Science.gov (United States)

    Gan, J; Lee, S J; Liu, W P; Haver, D L; Kabashima, J N

    2005-01-01

    Pyrethroids are commonly used insecticides in both agricultural and urban environments. Recent studies showed that surface runoff facilitated transport of pyrethroids to surface streams, probably by sediment movement. Sediment contamination by pyrethroids is of concern due to their wide-spectrum aquatic toxicity. In this study, we characterized the spatial distribution and persistence of bifenthrin [BF; (2-methyl(1,1'-biphenyl)-3-yl)methyl 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate] and permethrin [PM; 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid (3-phenoxyphenyl)methyl ester] in the sediment along a 260-m runoff path. Residues of BF and PM were significantly enriched in the eroded sediment, and the magnitude of enrichment was proportional to the downstream distance. At 145 m from the sedimentation pond, BF was enriched by >25 times, while PM isomers were enriched by >3.5 times. Pesticide enrichment along the runoff path coincided with enrichment of organic carbon and clay fractions in the sediment, as well as increases in adsorption coefficient K(d), suggesting that the runoff flow caused selective transport of organic matter and chemical-rich fine particles. Long persistence was observed for BF under both aerobic and anaerobic conditions, and the half-life ranged from 8 to 17 mo at 20 degrees C. The long persistence was probably caused by the strong pesticide adsorption to the solid phase. The significant enrichment, along with the prolonged persistence, suggests that movement of pyrethroids to the surface water may be caused predominantly by the chemically rich fine particles. It is therefore important to understand the fate of sediment-borne pyrethroids and devise mitigation strategies to reduce offsite movement of fine sediment.

  18. Molecular Mechanisms of Pyrethroid Insecticide Neurotoxicity: Recent Advances

    Science.gov (United States)

    Soderlund, David M.

    2011-01-01

    Synthetic pyrethroid insecticides were introduced into widespread use for the control of insect pests and disease vectors more than three decades ago. In addition to their value in controlling agricultural pests, pyrethroids are at the forefront of efforts to combat malaria and other mosquito-borne diseases and are also common ingredients of household insecticide and companion animal ectoparasite control products. The abundance and variety of pyrethroid uses contribute to the risk of exposure and adverse effects in the general population. The insecticidal actions of pyrethroids depend on their ability to bind to and disrupt voltage-gated sodium channels of insect nerves. Sodium channels are also important targets for the neurotoxic effects of pyrethroids in mammals but other targets, particularly voltage-gated calcium and chloride channels, have been implicated as alternative or secondary sites of action for a subset of pyrethroids. This review summarizes information published during the past decade on the action of pyrethroids on voltage-gated sodium channels as well as on voltage-gated calcium and chloride channels and provides a critical re-evaluation of the role of these three targets in pyrethroid neurotoxicity based on this information. PMID:21710279

  19. Evaluation of organophosphorus and synthetic pyrethroid insecticides against six vector mosquitoe species Avaliação de inseticidas organofosforados e piretroides sintéticos contra seis mosquitos vetores

    Directory of Open Access Journals (Sweden)

    Domingo Montada Dorta

    1993-12-01

    Full Text Available Three organophosphorus compounds- malathion, folithion and temephos- and two synthetic pyrethroids- alphamethrin and deltamethrin- were used for monitoring the susceptibility status of larvae and adults of six vector mosquitoe species: Culex quinquefasciatus (Filariasis and Aedes albopictus (Dengue (both laboratory and field strains; laboratory strains of Aedes aegypti (Dengue, Anopheles slephensi and Anopheles culicifacies (Malaria, and Culex tritaeniorhynchus (Japanese encephalitis in India. From the LC50 values obtained for these insecticides, it was found that all mosquito species including the field strains of Cx. quinquefasciatus and Ae. albopictus were highly susceptible Except for Cx. quinquefasciatus (field strain against malathion, 100% mortality was observed at the discriminating dosages recommended by World Health Organization. The residual effect of alphamethrin, deltamethrin, malathion and folithion at 25 mg (ai/m² on different surfaces against six species of vector mosquitoes showed that alphamethrin was the most effective on all four treated surfaces (mud, plywood, cement and thatch. Nevertheless, residual efficacy lasted longer on thatch than on the other surfaces. Therefore, synthetic pyrethroids such as alphamethrin can be effectively employed in integrated vector control operations.Três compostos organo-fosforados - malation, folition e temefos -e dois piretroides sintéticos - alfametrina e deltametrina - foram usados para controlar o estado da susceptibilidade das larvas e adultos de seis mosquitos vetores na Índia. Foram utilizadas cepas de laboratório e área de Culex quinquefasciatus (filariasis e Aedes albopictus (Dengue e cepas de laboratório de Aedes aegypti (Dengue, Anopheles stephensi e Anopheles culicifacies (Malária e Culex tritaenorhynchus (encefalite japonesa. Os valores de C1(50 obtidos para esses inseticidas mostram que todas as espécies incluindo as cepas de área foram muito susceptíveis. Nos

  20. Fast Gas Chromatography with Tandem Mass Spectrometry Analysis of Selected Persistent Organic Pollutants and Organophosphorus and Synthetic Pyrethroid Pesticides in Indian Prawn (Fenneropenaeus indicus) in Compliance with the EU-MRLs.

    Science.gov (United States)

    Sawant, Durvesh; Kelkar, Jitendra; Rasam, Pratap; Datar, Ajit; Hase, Prashant; Handique, Dheeraj; Bhone, Ankush; Chiplunkar, Sanket; Hate, Manish

    2017-05-01

    A fast GC with tandem MS method was developed and validated for multiresidue determination of 95 chemical contaminants (24 synthetic pyrethroids, 17 organochlorines, 17 organophosphorus compounds, 18 polycyclic aromatic hydrocarbons, and 19 polychlorinated biphenyls) in Indian prawns (Fenneropenaeus indicus) as per the European Union maximum residual limit requirements. Chromatographic separation and MS determination were achieved within a short run time of 18 min, without compromising sensitivity and specificity. Our findings revealed a 2.5× reduction in the run time compared with conventional GC methods. Sample preparation involved a QuEChERS-based extraction of 10 g sample with 10 mL acidified acetonitrile (1% acetic acid) and phase separation with 6 g anhydrous magnesium sulfate and 1.5 g sodium acetate. The extract was cleaned in two steps, first by dispersive cleanup with primary secondary amine and then by C18 SPE cartridge. The regression coefficients of linearity (r2) for the concentration range of 5-50 ng/mL were >0.99 for all the compounds. Recoveries at 5 and 10 ng/g levels were within the acceptable range of 70-120%. The repeatability (RSDr) and within-laboratory reproducibility (RSDwR) precisions were ≤20%. The method was successfully applied for analysis of the real world samples for incurred residues.

  1. Occurrence and bioavailability of pyrethroids in a mixed land use watershed.

    Science.gov (United States)

    Budd, R; Bondarenko, S; Haver, D; Kabashima, J; Gan, J

    2007-01-01

    The shift in land use patterns within many urban areas has the potential to influence the magnitude and nature of nonpoint-source pollution. The presence of pyrethroid insecticides in urban surface streams is of particular concern due to the broad spectrum toxicity of pyrethroids to aquatic organisms and the widespread use of pyrethroid products for agricultural and urban pest control. Sediment samples were collected throughout a mixed land use watershed in southern California during two sampling periods and analyzed for a suite of pyrethroids. Bifenthrin and fenpropathrin were found most frequently in the sediment samples, with the highest concentrations associated with sites adjacent to large commercial nurseries. Sediments from residential areas or residential-commercial mixed areas had fewer detections and significantly lower concentrations than the nursery runoff sediments. No apparent difference was found between wet and dry season concentrations, which may be attributed to the fact that the lack of flow under dry weather conditions rendered pyrethroid residues immobile. Organic carbon-normalized sediment concentrations were poorly correlated with the freely dissolved pore water concentrations measured by solid phase microextraction (SPME), suggesting factors other than sediment organic carbon content should be considered when relating concentrations to potential toxicities.

  2. Pyrethrins and Pyrethroids

    Science.gov (United States)

    This page includes information on the use of pyrethrins and pyrethroids as insecticides, the current reevaluation of this group of pesticides in registration review, and previous assessments, decisions, and risk mitigation efforts.

  3. Evaluation of Lactobacillus plantarum and Saccharomyces cerevisiae in the Presence of Bifenthrin.

    Science.gov (United States)

    Đorđević, Tijana M; Đurović-Pejčev, Rada D

    2016-06-01

    This work describes the effect of insecticide bifenthrin on Lactobacillus plantarum and Saccharomyces cerevisiae. Growths of used microorganisms in growth media supplemented with pesticide were studied. Determination of bacterial and yeast fermentation efficiency in wheat supplemented with bifenthrin was conducted. Additionally, investigation of bifenthrin dissipation during microbiological activity was performed. Experiments applying bifenthrin in different concentrations highlighted a negligible impact of the pesticide on the growth of L. plantarum and S. cerevisiae. This insecticide overall negatively affected the yeast fermentation of wheat, while its presence in wheat had a slight negative impact on lactic acid fermentation. The results of bifenthrin dissipation during lactic acid and yeast fermentations of wheat showed that activities of L. plantarum and S. cerevisiae caused lower pesticide reductions. Average bifenthrin residue reduction within samples fermented with L. plantarum was 5.4 % (maximum ~16 %), while within samples fermented with S. cerevisiae, it was 11.6 % (maximum ~17 %).

  4. Pyrethroids: exposure and health effects--an update.

    Science.gov (United States)

    Saillenfait, Anne-Marie; Ndiaye, Dieynaba; Sabaté, Jean-Philippe

    2015-05-01

    Synthetic pyrethroids are present in numerous commercial insecticide formulations and have extensive indoor and outdoor applications worldwide, including agricultural, public, residential, and veterinary usages for pest control. Pyrethroid use has increased continuously in recent years. The aim of this review is to provide updated and comprehensive information on human exposure and potential hazards associated with this class of pesticides. An initial keyword search in the PubMed database was conducted to identify relevant articles. Were taken into considerations only the studies published in the last decade that have assessed exposure and health effects of pyrethroids in human populations. Literature review shows that exposure evaluations increasingly focus on biomonitoring and that a large number of recent epidemiological studies pertain to the effects of pyrethroids on male fertility and prenatal development. The main metabolites of pyrethroids have frequently been detected in urine samples from the general population, confirming widespread exposure of children and adults to one or more pyrethroids. Non-occupational exposure to pyrethroids mainly occurs through ingestion of residues in food, or ingestion of or dermal contact with contaminated house dust or surface-adhering particles, following domestic use. Although clinical features resulting from acute accidental exposure to pyrethroids are well described (e.g., paraesthesiae, and respiratory, eye and skin irritation), information regarding their chronic effects at low concentrations is both limited and controversial. Several recent epidemiological studies have raised concerns about potentially adverse effects on sperm quality and sperm DNA, reproductive hormones, and pregnancy outcomes. Early neurobehavioural development after in utero exposure is discussed. Further research is needed to clarify the possible risks associated with long-term environmental exposure to pyrethroids. Copyright © 2015 Elsevier Gmb

  5. BLOOD AND BRAIN CONCENTRATIONS OF BIFENTHRIN CORRELATE WITH DECREASED MOTOR ACTIVITY INDEPENDENT OF TIME OF EXPOSURE

    Science.gov (United States)

    Pyrethroids are neurotoxic insecticides used in a variety of agricultural and household activities. Due to the phase-out of organophosphate pesticides, the use of pyrethroids has increased. The potential for human exposure to pyrethroids has prompted pharmacodynamic and pharmac...

  6. Enantioselective disruption of the endocrine system by Cis-Bifenthrin in the male mice.

    Science.gov (United States)

    Jin, Yuanxiang; Wang, Jiangcong; Pan, Xiuhong; Miao, Wenyu; Lin, Xiaojian; Wang, Linggang; Fu, Zhengwei

    2015-07-01

    Bifenthrin (BF), as a chiral pyrethroid, is widely used to control field and household pests in China. At present, the commercial BF is a mixed compound containing cis isomers (cis-BF) including two enantiomers of 1R-cis-BF and 1S-cis-BF. In the present study, the two individual cis-BF enantiomers were separated by a preparative supercritical fluid chromatography. Then, four week-old adolescent male ICR mice were orally administered 1R-cis-BF and 1S-cis-BF separately daily for 3 weeks at doses of 0, 7.5 and 15 mg/kg/day, respectively. Results showed that the transcription status of some genes involved in cholesterol synthesis and transport as well as testosterone (T) synthesis in the testes were influenced by cis-BF enantiomers. Especially, we observed that the transcription status of key genes on the pathway of T synthesis including cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc) and cytochrome P450 17α-hydroxysteroid dehydrogenase (P45017α)) were selectively altered in the testis of mice when treated with 1S-cis-BF, suggesting that it is the possible reason to explain why the lower serum T concentration in 1S-cis-BF treated group. Taken together, it concluded that both of the cis-BF enantiomers have the endocrine disruption activities, while 1S-cis-BF was higher than 1R-cis-BF in mice when exposed during the puberty. The data was helpful to understand the toxicity of cis-BF in mammals under enantiomeric level. © 2014 Wiley Periodicals, Inc.

  7. Determination of Pyrethroids in Tea Brew by GC-MS Combined with SPME with Multiwalled Carbon Nanotube Coated Fiber

    Directory of Open Access Journals (Sweden)

    Dongxia Ren

    2018-01-01

    Full Text Available A new method has been developed to simultaneously determine 7 pyrethroid residues in tea brew using gas chromatography-mass spectrometry (GC-MS combined with solid phase microextraction (SPME with multiwalled carbon nanotubes (MWCNTs coated fiber. The MWCNTs coated fiber of SPME was homemade by using stainless steel wire as coating carrier and polyacrylonitrile (PAN solution as adhesive glue. Under the optimized conditions, a good linearity was shown for bifenthrin, fenpropathrin, permethrin, and cyfluthrin in 1–50 ng mL−1 and for cypermethrin, fenvalerate, and deltamethrin in 5–50 ng mL−1. The correlation coefficients were in the range of 0.9948–0.9999. The average recoveries of 7 pyrethroids were 94.2%–107.3% and the relative standard deviations (RSDs were less than 15%. The detection limit of the method ranged from 0.12 to 1.65 ng mL−1. The tea brew samples made from some commercial tea samples were analyzed. Among them, bifenthrin, fenpropathrin, and permethrin were found. The results show that the method is rapid and sensitive and requires low organic reagent consumption, which can be well used for the detection of the pyrethroids in tea brew.

  8. Lambda-Cyhalothrin Resistance in the Lady Beetle Eriopis connexa (Coleoptera: Coccinellidae) Confers Tolerance to Other Pyrethroids.

    Science.gov (United States)

    Torres, J B; Rodrigues, A R S; Barros, E M; Santos, D S

    2015-02-01

    Pyrethroid insecticides are widely recommended to control insect defoliators but lack efficacy against most aphid species. Thus, conserving aphid predators such as the lady beetle Eriopis connexa (Germar) is important to pest management in crop ecosystems that require pyrethroid sprays. In a greenhouse, early fourth-instar larvae and 5-day-old adults from susceptible (S) and resistant (R) E. connexa populations were caged on lambda-cyhalothrin-treated cotton plants, after which survival and egg production (for those caged at adult stage) were assessed. In the laboratory, similar groups were subjected to dried residues and topical treatment with one of eight pyrethroids (alpha-cypermethrin, bifenthrin, deltamethrin, esfenvalerate, fenpropathrin, permethrin, zeta-cypermethrin, and lambda-cyhalothrin), the organophosphate methidathion, or water and wetting agent. After caging on treated cotton terminals, 66% of the R-population larvae survived to adulthood, compared with 2% of those from the S-population. At 12 d after caging at adult stage under the same conditions, 64% of the females from the R-population survived and laid eggs, compared with 100% mortality and no oviposition for the S-females. In trials involving dried insecticide residues, gain in survival based on the survival difference (percentage for R-population minus percentage for S-population) across all tested pyrethroids varied from 3 to 63% for larvae and from 3 to 70% for adults. In trials involving topical sprays of the tested pyrethroids, survival differences ranged from 36 to 96% for larvae and from 21 to 82% for adults. Fenpropathrin and bifenthrin were the least and most toxic, respectively. © 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.

  9. Effect of subacute poisoning with bifenthrin on locomotor activity, memory retention, haematological, biochemical and histopathological parameters in mice.

    Science.gov (United States)

    Nieradko-Iwanicka, B; Borzecki, A; Jodlowska-Jedrych, B

    2015-02-01

    Bifenthrin (BIF) is a pyrethroid (PYR) insecticide. The target point for PYR's toxic action are voltage sensitive sodium channels in the central nervous system (CNS). Intoxication with PYRs results in motor activity impairment and death in insects. Although PYRs are considered to be safe for mammals, there were numerous cases of pyrethroid poisoning in humans, animals and pets described. The general population is chronically exposed to PYRs via grain products, dust and indoor air. Therefore new questions arise: whether PYRs act in a dose-additive fashion in the course of subacute poisoning, are there other target organs (but brain) for BIF and if there is one common mechanism of its' toxic action in different organs. The objective of this work was to characterize the effect of BIF at the doses of 4 or 8 mg/kg injected intraperitoneally (i.p.) daily for 28 consecutive days on memory and motor activity, hematological, biochemical and histopathological parameters in mice. BIF at the doses of 8 mg/kg or 4 mg/kg of body mass was administered i.p. daily to the mice for 28 consecutive days. Motor function was measured on day 1, 7, 14 and 28 and memory retention was tested in a passive avoidance task on day 2, 7, 14 and 28. BIF significantly impaired memory retention on day 2. BIF decreased locomotor activity at every stage of the experiment in a single dose depending manner. No behavioral cumulative effect was observed. Subacute poisoning with the higher dose of BIF caused anaemia, elevated white blood cell count (WBC), elevated alanine transaminase (ALT), superoxide dismuthase (SOD), and decreased glutathione peroxidase (GPx) activity. Lymphocyte infiltrates were visualized in the livers. subacute poisoning with BIF decreases locomotor activity in a single dose proportionate manner. BIF damages also the liver and alters blood morphology. The possible common mechanism of these effects can be oxidative stress.

  10. Conformational properties of pyrethroids

    Science.gov (United States)

    Mullaley, Anne; Taylor, Robin

    1994-04-01

    X-ray database searches and theoretical potential-energy calculations indicate that the acid moieties of pyrethroid cyclopropanecarboxylate esters adopt a well-defined, relatively inflexible conformation. In contrast, the alcohol moieties can exist in many low-energy geometries. One of the least conformationally flexible pyrethroid alcohols is 4-phenylindan-2-ol. The approximate overall conformation adopted at the biological binding site by insecticidal esters of this alcohol can be deduced with reasonable confidence by molecular modelling. Graphics superposition of a variety of pyrethroid acids suggests the existence of a large but rather narrow pocket at the binding site, in which substituents at the 3-position of the cyclopropane ring can be accommodated. This pocket is asymmetric with respect to the plane of the cyclopropane ring, extending further on the side remote from the ester group. The effects of α-substitution on the insecticidal activity of pyrethroid esters may be due to the influence of substituents on the preferred conformations of the molecules. This hypothesis rationalises the paradoxical dependence on absolute stereochemistry of the activities of various allylbenzyl and cinnamyl alcohol derivatives.

  11. A two-component mass balance model for calibration of solid-phase microextraction fibers for pyrethroids in seawater.

    Science.gov (United States)

    Lao, Wenjian; Maruya, Keith A; Tsukada, David

    2012-11-06

    Determination of the analyte-specific distribution coefficient between the aqueous and sorbing phases is required for estimation of the aqueous-phase concentration of the analyte of interest using polymeric materials. Poly(dimethylsiloxane)-coated solid-phase microextration (PDMS-SPME) fiber-water partition coefficient (K(f)) values for eight common-use pyrethroids were determined using a two-compartment mass balance model and parameters determined in experimental seawater microcosms. Mass balance, epimerization, and aqueous-phase degradation (i.e., hydrolysis) were characterized using gas chromatography-negative chemical ionization mass spectrometry to facilitate K(f) estimation. Of the eight pyrethroids, only bifenthrin exhibited increasing sorption on the SPME fiber over the entire time-series exposure, indicating that its K(f) value could be estimated through a stable-compound model. The remaining pyrethroids were found to be unstable (half-life of 0.98) and the remaining unstable pyrethroids (R(2) > 0.7), leading to estimated values of log K(f) between 5.7 and 6.4, after correcting for residual dissolved organic carbon (DOC) in the experimental seawater. These K(f) values can be used to determine freely dissolved pyrethroid concentrations in the pg/L range using PDMS-SPME in fresh or seawater matrices under equilibrium conditions in laboratory or field applications.

  12. Pyrethroid insecticide concentrations and toxicity in streambed sediments and loads in surface waters of the San Joaquin Valley, California, USA

    Science.gov (United States)

    Domagalski, Joseph L.; Weston, Donald P.; Zhang, Minghua; Hladik, Michelle L.

    2010-01-01

    Pyrethroid insecticide use in California, USA, is growing, and there is a need to understand the fate of these compounds in the environment. Concentrations and toxicity were assessed in streambed sediment of the San Joaquin Valley of California, one of the most productive agricultural regions of the United States. Concentrations were also measured in the suspended sediment associated with irrigation or storm‐water runoff, and mass loads during storms were calculated. Western valley streambed sediments were frequently toxic to the amphipod, Hyalella azteca, with most of the toxicity attributable to bifenthrin and cyhalothrin. Up to 100% mortality was observed in some locations with concentrations of some pyrethroids up to 20 ng/g. The western San Joaquin Valley streams are mostly small watersheds with clay soils, and sediment‐laden irrigation runoff transports pyrethroid insecticides throughout the growing season. In contrast, eastern tributaries and the San Joaquin River had low bed sediment concentrations (pyrethroids in irrigation and storm water runoff. Esfenvalerate, fenpropathrin, and resmethrin were also detected. All sampled streams contributed to the insecticide load of the San Joaquin River during storms, but some compounds detected in the smaller creeks were not detected in the San Joaquin River. The two smallest streams, Ingram and Hospital Creeks, which had high sediment toxicity during the irrigation season, accounted for less than 5% of the total discharge of the San Joaquin River during storm conditions, and as a result their contribution to the pyrethroid mass load of the larger river was minimal. 

  13. Inter-compartmental transport of organophosphate and pyrethroid pesticides in South China: Implications for a regional risk assessment

    International Nuclear Information System (INIS)

    Li, Huizhen; Wei, Yanli; Lydy, Michael J.; You, Jing

    2014-01-01

    The dynamic flux of an organophosphate and four pyrethroid pesticides was determined in an air-(soil)-water-sediment system based on monitoring data from Guangzhou, China. The total air–water flux, including air–water gaseous exchange and atmospheric deposition, showed deposition from air to water for chlorpyrifos, bifenthrin and cypermethrin, but volatilization for lambda-cyhalothrin and permethrin. The transport of the pesticides from overlying water to sediment suggested that sediment acted as a sink for the pesticides. Additionally, distinct annual atmospheric depositional fluxes between legacy and current-use pesticides suggested the role of consumer usage in their transport throughout the system. Finally, pesticide toxicity was estimated from annual air–water-sediment flux within an urban stream in Guangzhou. A dynamic flux-based risk assessment indicated that inter-compartmental transport of chlorpyrifos decreased its atmospheric exposure, but had little influence on its aquatic toxicity. Instead, water-to-sediment transport of pyrethroids increased their sediment toxicity, which was supported by previously reported toxicity data. - Highlights: • Transport fluxes of chlorpyrifos and pyrethroids were assessed in Guangzhou, China. • Sediment acted as a sink for chlorpyrifos and pyrethroids. • Air-to-water transport decreased the exposure risk of atmospheric chlorpyrifos. • Dynamic transport might increase the risk of pyrethroids in air and sediment. • Flux-based pesticide concentrations provide a way to estimate sediment toxicity. - Regional risk assessment could be improved by integrating dynamic flux information derived from inter-compartmental models

  14. Analysis of pyrethroids in air using commercial XAD sampling ...

    African Journals Online (AJOL)

    Pyrethroids are synthetic esters used commercially as pesticides. They are readily available as active components of numerous over-the-counter products for control of household pests mainly formulated as sprays (aerosols), powders and for application via electro-evaporators. The potential for toxic effects in humans from ...

  15. Immunotoxicity of the pyrethroid insecticides deltametrin and alpha-cypermetrin

    DEFF Research Database (Denmark)

    Madsen, Charlotte Bernhard; Claesson, M. H.; Ropke, C.

    1996-01-01

    The synthetic pyrethroids deltametrin and alpha-cypermetrin were studied for effects on the immune system in 28-day studies in F344 male rats. Sixteen rats per group were dosed with either deltametrin 0, 1, 5, or 10 mg/kg body wt./day or alpha-cypermetrin 0, 4, 8, or 12 mg/kg body wt./day in soy...

  16. Immunotoxicity of the pyrethroid insecticides deltametrin and alpha-cypermetrin

    DEFF Research Database (Denmark)

    Madsen, Charlotte Bernhard; Claesson, M. H.; Ropke, C.

    1996-01-01

    The synthetic pyrethroids deltametrin and alpha-cypermetrin were studied for effects on the immune system in 28-day studies in F344 male rats. Sixteen rats per group were dosed with either deltametrin 0, 1, 5, or 10 mg/kg body wt./day or alpha-cypermetrin 0, 4, 8, or 12 mg/kg body wt./day in soy ...

  17. Activity of bifenthrin, chlorfenapyr, fipronil, and thiamethoxam against Argentine ants (Hymenoptera: Formicidae).

    Science.gov (United States)

    Wiltz, B A; Suiter, D R; Gardner, W A

    2009-12-01

    Bifenthrin, chlorfenapyr, fipronil, and thiamethoxam were evaluated for activity against the Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae). Mobility impairment and lethal times were determined after topical treatments. Ants were immobilized most quickly by bifenthrin, followed by chlorfenapyr and thiamethoxam. After 2 h, the number of fipronil-treated ants unable to walk out of test arenas did not differ from control ants. Median lethal time (LT50) after topical treatment was lowest in the bifenthrin treatment, followed by thiamethoxam, chlorfenapyr, and then fipronil. Mortality due to horizontal exposure was evaluated at 10, 20, or 30 degrees C, with topically treated ant corpses serving as donors. There was low to moderate horizontal activity in bifenthrin and chlorfenapyr treatments, with no temperature effect in bifenthrin treatments and a positive temperature effect in chlorfenapyr treatments. Mortality in the fipronil treatments was highest and was positively correlated with temperature. Thiamethoxam treatments did not differ from controls at 10 degrees C, but mortality increased with temperature. To evaluate contact activity, either all of 20% of the ants in a cohort were exposed to insecticide-treated pine needles. In both tests, mortality was highest in fipronil and bifenthrin treatments, followed by thiamethoxam, with lowest mortality in chlorfenapyr treatments. Effectiveness as a barrier was evaluated by providing a choice between bridges treated with insecticide or water. Although bifenthrin did not provide an impenetrable barrier, it was the only treatment having fewer ants than its paired control. Mortality data suggest that lack of recruitment rather than repellency account for this result.

  18. Synthetic

    Directory of Open Access Journals (Sweden)

    Anna Maria Manferdini

    2010-06-01

    Full Text Available Traditionally materials have been associated with a series of physical properties that can be used as inputs to production and manufacturing. Recently we witnessed an interest in materials considered not only as ‘true matter’, but also as new breeds where geometry, texture, tooling and finish are able to provoke new sensations when they are applied to a substance. These artificial materials can be described as synthetic because they are the outcome of various qualities that are not necessarily true to the original matter, but they are the combination of two or more parts, whether by design or by natural processes. The aim of this paper is to investigate the potential of architectural surfaces to produce effects through the invention of new breeds of artificial matter, using micro-scale details derived from Nature as an inspiration.

  19. PYRETHROID INSECTICIDES: ISOFORM-DEPENDENT HYDROLYSIS, INDUCTION OF CYTOCHROME P450 3A4 AND EVIDENCE ON THE INVOLVEMENT OF THE PREGNANE X RECEPTOR

    Science.gov (United States)

    Yang, Dongfang; Wang, Xiliang; Chen, Yi-tzai; Deng, Ruitang; Yan, Bingfang

    2009-01-01

    Pyrethroids account for more than one-third of the insecticides currently marketed in the world. In mammals, these insecticides undergo extensive metabolism by carboxylesterases and cytochrome P450s (CYPs). In addition, some pyrethroids are found to induce the expression of CYPs. The aim of this study was to determine whether pyrethroids induce carboxylesterases and CYP3A4, and whether the induction is correlated inversely with their hydrolysis. Human liver microsomes were pooled and tested for the hydrolysis of 11 pyrethroids. All pyrethroids were hydrolyzed by the pooled microsomes, but the hydrolytic rates varied by as many as 14 fold. Some pyrethroids such as bioresmethrin were preferably hydrolyzed by carboxylesterase HCE1, whereas others such as bifenthrin preferably by HCE2. In primary human hepatocytes, all pyrethroids except tetramethrin significantly induced CYP3A4. In contrast, insignificant changes were detected on the expression of carboxylesterases. The induction of CYP3A4 was confirmed in multiple cell lines including HepG2, Hop92 and LS180. Overall, the magnitude of the induction was correlated inversely with the rates of hydrolysis, but positively with the activation of the pregnane X receptor (PXR). Transfection of a carboxylesterase markedly decreased the activation of PXR, and the decrease was in agreement with carboxylesterase-based preference for hydrolysis. In addition, human PXR variants as well as rat PXR differed from human PXR (wild-type) in responding to certain pyrethroids (e.g., lambda-cyhalothrin), suggesting that induction of PXR target genes by these pyrethroids varies depending on polymorphic variants and the PXR species identity. PMID:19249324

  20. Antiplasmodial and antitrypanosomal activity of pyrethrins and pyrethroids.

    Science.gov (United States)

    Hata, Yoshie; Zimmermann, Stefanie; Quitschau, Melanie; Kaiser, Marcel; Hamburger, Matthias; Adams, Michael

    2011-09-14

    In a screen of 1800 plant and fungal extracts for antiplasmodial, antitrypanosomal, and leishmanicidal activity, the n-hexane extract of Chrysanthemum cinerariifolium (Trevir.) Vis. flowers showed strong activity against Plasmodium falciparum. We isolated the five pyrethrins [i.e., pyrethrin II (1), jasmolin II (2), cinerin II (3), pyrethrin I (4), and jasmolin I (5)] from this extract. These were tested together with 15 synthetic pyrethroids for their activity against P. falciparum and Trypanosoma brucei rhodesiense and for cytotoxicity in rat myoblast L6 cells. The natural pyrethrins showed antiplasmodial activity with IC(50)s between 4 and 12 μM, and antitrypanosomal activity with IC(50)s from 7 to 31 μM. The pyrethroids exhibited weaker antiplasmodial and antitrypanosomal activity than the pyrethrins. Both pyrethrins and pyrethroids showed moderate cytotoxicity against L6 cells. Pyrethrin II (1) was the most selective antiplasmodial compound, with a selectivity index of 24.

  1. Neurobehavioral toxicology of pyrethroid insecticides

    Energy Technology Data Exchange (ETDEWEB)

    Crofton, K.M.

    1986-01-01

    Pyrethroid insecticides are classified as either Type I or Type II based upon in vivo toxic signs, and neurophysiological and biochemical data. Both axonal sodium channels and the ..gamma..-aminobutyric acid (GABA) receptor complex have been proposed as the major site of action of the Type II pyrethroids. This investigation characterized the behavior and biochemical effects of low dosages of pyrethroids in rats. Type I and II pyrethroids were tested for effects on figure-eight maze activity and the acoustic startle response (ASR). All compounds decreased figure-eight maze activity. Interactions of Type I and II pyrethroids with the three major binding sites on the GABA complex were determined in vivo. Radioligand binding experiments assessed in vitro interactions of pyrethroids with the three major GABA-complex binding sites. None of the pyrethroids competed for (/sup 3/H)-muscimol or (/sup 3/H)-flunitrazepam binding. Only Type II pyrethroids inhibited binding of (/sup 35/S)-t-butylbicyclophosphorothionate (TBPS) in cortical synaptosome preparations with K/sub i/ values of 5 to 10 ..mu..M. The (/sup 35/S)-TBPS data implicate the TBPS/picrotoxinin binding site in the mechanism of Type II pyrethroid toxicity. The results of these experiments support the classification of pyrethroids into two classes, and demonstrate the utility of the figure-eight maze and the ASR in studies to elucidate neurotoxic mechanisms. The interaction of the Type II pyrethroids is probably restricted to the TBPS/picrotoxinin binding domain on the GABA complex as shown by both the in vivo and in vitro studies.

  2. Determination of seven pyrethroids biocides and their synergist in indoor air by thermal-desorption gas chromatography/mass spectrometry after sampling on Tenax TA ® passive tubes.

    Science.gov (United States)

    Raeppel, Caroline; Appenzeller, Brice M; Millet, Maurice

    2015-01-01

    A method coupling thermal desorption and gas chromatography/mass spectrometry (GC/MS) was developed for the simultaneous determination of 7 pyrethroids (allethrin, bifenthrin, cyphenothrin, imiprothrin, permethrin, prallethrin and tetramethrin) and piperonyl butoxide adsorbed on Tenax TA(®) passive samplers after exposure in indoor air. Thermal desorption was selected as it permits efficient and rapid extraction without solvent used together with a good sensitivity. Detection (S/N>3) and quantification (S/N>10) limits varied between 0.001 ng and 2.5 ng and between 0.005 and 10 ng respectively with a reproducibility varied between 14% (bifenthrin) and 39% (permethrin). The method was used for the comparison indoor air contamination after low-pressure spraying and fumigation application in a rubbish chute situated in the basement of a building. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. The estrogenic and androgenic potential of pyrethroids in vitro. Review.

    Science.gov (United States)

    Saillenfait, Anne-Marie; Ndiaye, Dieynaba; Sabaté, Jean-Philippe

    2016-08-01

    Synthetic pyrethroids are used worldwide as insecticides. Their metabolites are regularly detected in the urine of adults and children from the general population. There is increasing concern that they may induce sex-hormone disrupting effects. The present work reviews available published information on the (anti)estrogenic and (anti)androgenic activity of pyrethroids in in vitro screening tests. In recent years, a large number of pyrethroids have been evaluated using various common testing methods. In tests using recombinant yeast or mammalian cells, the pyrethroids were found to be essentially negative or weakly estrogenic. More inconsistent results were found regarding their estrogenic action in proliferation tests. Conflicting findings were also reported across studies and/or assays which evaluated their anti-estrogenic or anti-androgenic potential. Some studies have suggested that certain pyrethroids may have potential antagonist activity. However, no strong interaction with the estrogenic or androgenic pathway was reported. The present review confirms the interest in performing a screening battery and in adopting an integrative approach for identifying the potential of different compounds from a chemical family to interfere with the endocrine system. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Synthesis of AzPhchitosan-bifenthrin-PVC to protect cables against termites.

    Science.gov (United States)

    Zhang, Lingkun; Cai, Weiwei; Chen, Wu-Ya; Zhang, Li; Hu, Kaikai; Guan, Yan-Qing

    2016-03-30

    The destruction of PVC cables by termites is a continuing and long-standing problem, which can lead to power leakage and power cut. Given the environmental demerits of insecticide overuse, alternative methods of addressing this problem are a highly desirable goal. In this study, we used photo-immobilization to develop a chitosan carrier system to help bifenthrin immobilize on the surface of the PVC substrate. The immobilization was analyzed using nuclear magnetic resonance (NMR), UV absorption, reverse-phase high-performance liquid chromatography (RP-HPLC), Raman absorption spectroscopy, and thermal gravimetric analysis (TGA). The surface structure and biological activity of the embedded and immobilized bifenthrin were examined using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photon-electron spectroscopy (XPS). Its efficacy was assessed in pest experiments. The results indicate a successful embedding and immobilization of bifenthrin. Furthermore, the chemical bonding network between AzPhchitosan, bifenthrin, and PVC is stable, guaranteeing no environmental release of bifenthrin, and also providing more efficacious protection against termites. The evidence suggests that this photo-immobilization of bifenthrin-embedded chitosan on the surface of PVC substrates is a novel and environmentally friendly technique for termite control. This paper also reports a modification of chitosan with respect to its novel application in environmental protection. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Treated wastewater effluent as a source of pyrethroids and fipronil at todos santos bay, Mexico: Its impact on sediments and organisms.

    Science.gov (United States)

    Hernández-Guzmán, Félix Augusto; Macías-Zamora, José Vinicio; Ramírez-Álvarez, Nancy; Alvarez-Aguilar, Arturo; Quezada-Hernández, Cristina; Fonseca, Ana Paula

    2017-11-01

    Pyrethroids are insecticides widely used to control pests and disease vectors in residential areas and agricultural lands. Pyrethroids are emerging pollutants, and their use is a growing concern because of their toxicity potential to aquatic organisms. Todos Santos Bay and the Punta Banda estuary, 2 coastal bodies located to the south of the Southern California Bight, were studied to establish a baseline of the current conditions of pollution by pyrethroids and fipronil. Eight pyrethroids, along with fipronil and its 2 metabolites, were determined in effluents from wastewater-treatment plants (n = 3), surface sediments (n = 32), and 3 locations with mussels (Mytilus californianus, n = 9). Bifenthrin, permethrin, and cypermethrin were the most common pyrethroids found in the study areas and were widespread in sediments, mussels, and wastewater-treated effluents. Fipronil and its metabolites were detected in mussels and wastewater-treated effluents only. Total pyrethroid concentrations in sediments ranged from 0.04 to 1.95 ng/g dry weight in the Punta Banda estuary (n = 13) and from 0.07 to 6.62 ng/g dry weight in Todos Santos Bay (n = 19). Moreover, total pyrethroids in mussels ranged from 1.19 to 6.15 ng/g wet weight. Based on the toxic unit data calculated for pyrethroids and fipronil for Eohaustorius estuarius and Hyalella azteca, little to no impact is expected to the benthic population structure. Environ Toxicol Chem 2017;36:3057-3064. © 2017 SETAC. © 2017 SETAC.

  6. Microwave-assisted extraction of pyrethroid insecticides from semi permeable membrane devices (SPMDs) used to indoor air monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Esteve-Turrillas, Francesc A. [Analytical Chemistry Department, University of Valencia, Edifici Jeroni Munoz, 50th Dr. Moliner, 46100 Burjassot, Valencia (Spain); Pastor, Agustin [Analytical Chemistry Department, University of Valencia, Edifici Jeroni Munoz, 50th Dr. Moliner, 46100 Burjassot, Valencia (Spain)]. E-mail: agustin.pastor@uv.es; Guardia, Miguel de la [Analytical Chemistry Department, University of Valencia, Edifici Jeroni Munoz, 50th Dr. Moliner, 46100 Burjassot, Valencia (Spain)

    2006-02-23

    A rapid and environmentally friendly methodology was developed for the extraction of pyrethroid insecticides from semi permeable membrane devices (SPMDs), in which they were preconcentrated in gas phase. The method was based on gas chromatography mass-mass spectrometry determination after a microwave-assisted extraction, in front of the widely employed dialysis method. SPMDs were extracted twice with 30 mL hexane:acetone, irradiated with 250 W power output, until 90 deg. C in 10 min, this temperature being held for another 10 min. Clean-up of the extracts was performed by acetonitrile-hexane partitioning and solid-phase extraction (SPE) with a combined cartridge of 2 g basic-alumina, deactivated with 5% water, and 500 mg C{sub 18}. Pyrethroids investigated were Allethrin, Prallethrin, Tetramethrin, Bifenthrin, Phenothrin, {lambda}-Cyhalothrin, Permethrin, Cyfluthrin, Cypermethrin, Flucythrinate, Esfenvalerate, Fluvalinate and Deltamethrin. The main pyrethroid synergist compound, Pyperonyl Butoxide, was also studied. Limit of detection values ranging from 0.3 to 0.9 ng/SPMD and repeatability data, as relative standard deviation, from 2.9 to 9.4%, were achieved. Pyrethroid recoveries, for spiked SPMDs, with 100 ng of each one of the pyrethroids evaluated, were from 61 {+-} 8 to 103 {+-} 7% for microwave-assisted extraction, versus 54 {+-} 4 to 104 {+-} 3% for dialysis reference method. Substantial reduction of solvent consumed (from 400 to 60 mL) and analysis time (from 48 to 1 h) was achieved by using the developed procedure. High concentration levels of pyrethroid compounds, from 0.14 to 7.3 {mu}g/SPMD, were found in indoor air after 2 h of a standard application.

  7. Microwave-assisted extraction of pyrethroid insecticides from semi permeable membrane devices (SPMDs) used to indoor air monitoring

    International Nuclear Information System (INIS)

    Esteve-Turrillas, Francesc A.; Pastor, Agustin; Guardia, Miguel de la

    2006-01-01

    A rapid and environmentally friendly methodology was developed for the extraction of pyrethroid insecticides from semi permeable membrane devices (SPMDs), in which they were preconcentrated in gas phase. The method was based on gas chromatography mass-mass spectrometry determination after a microwave-assisted extraction, in front of the widely employed dialysis method. SPMDs were extracted twice with 30 mL hexane:acetone, irradiated with 250 W power output, until 90 deg. C in 10 min, this temperature being held for another 10 min. Clean-up of the extracts was performed by acetonitrile-hexane partitioning and solid-phase extraction (SPE) with a combined cartridge of 2 g basic-alumina, deactivated with 5% water, and 500 mg C 18 . Pyrethroids investigated were Allethrin, Prallethrin, Tetramethrin, Bifenthrin, Phenothrin, λ-Cyhalothrin, Permethrin, Cyfluthrin, Cypermethrin, Flucythrinate, Esfenvalerate, Fluvalinate and Deltamethrin. The main pyrethroid synergist compound, Pyperonyl Butoxide, was also studied. Limit of detection values ranging from 0.3 to 0.9 ng/SPMD and repeatability data, as relative standard deviation, from 2.9 to 9.4%, were achieved. Pyrethroid recoveries, for spiked SPMDs, with 100 ng of each one of the pyrethroids evaluated, were from 61 ± 8 to 103 ± 7% for microwave-assisted extraction, versus 54 ± 4 to 104 ± 3% for dialysis reference method. Substantial reduction of solvent consumed (from 400 to 60 mL) and analysis time (from 48 to 1 h) was achieved by using the developed procedure. High concentration levels of pyrethroid compounds, from 0.14 to 7.3 μg/SPMD, were found in indoor air after 2 h of a standard application

  8. Evidence for Soybean Aphid (Hemiptera: Aphididae) Resistance to Pyrethroid Insecticides in the Upper Midwestern United States.

    Science.gov (United States)

    Hanson, Anthony A; Menger-Anderson, James; Silverstein, Celia; Potter, Bruce D; MacRae, Ian V; Hodgson, Erin W; Koch, Robert L

    2017-10-01

    Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a damaging invasive pest of soybean in the upper Midwest. Threshold-based insecticide applications are the primary control method for soybean aphid, but few insecticide groups are available (i.e., pyrethroids, organophosphates, and neonicotinoids). To quantify current levels of soybean aphid susceptibility to pyrethroids in the upper Midwest and monitor for insecticide resistance, leaf-dip bioassays were performed with λ-cyhalothrin in 2013-2015, and glass-vial bioassays were performed with λ-cyhalothrin and bifenthrin in 2015 and 2016. Soybean aphids were collected from 27 population-years in Minnesota and northern Iowa, and were compared with a susceptible laboratory colony with no known insecticide exposure since discovery of soybean aphid in North America in 2000. Field-collected aphids from some locations in leaf-dip and glass-vial bioassays had significantly lower rates of insecticide-induced mortality compared with the laboratory population, although field population susceptibility varied by year. In response to sublethal concentrations of λ-cyhalothrin, adult aphids from some locations required higher concentrations of insecticide to reduce nymph production compared with the laboratory population. The most resistant field population demonstrated 39-fold decreased mortality compared with the laboratory population. The resistance documented in this study, although relatively low for most field populations, indicates that there has been repeated selection pressure for pyrethroid resistance in some soybean aphid populations. Integrated pest management and insecticide resistance management should be practiced to slow further development of soybean aphid resistance to pyrethroids. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. DDT, pyrethrins, pyrethroids and insect sodium channels.

    Science.gov (United States)

    Davies, T G E; Field, L M; Usherwood, P N R; Williamson, M S

    2007-03-01

    The long term use of many insecticides is continually threatened by the ability of insects to evolve resistance mechanisms that render the chemicals ineffective. Such resistance poses a serious threat to insect pest control both in the UK and worldwide. Resistance may result from either an increase in the ability of the insect to detoxify the insecticide or by changes in the target protein with which the insecticide interacts. DDT, the pyrethrins and the synthetic pyrethroids (the latter currently accounting for around 17% of the world insecticide market), act on the voltage-gated sodium channel proteins found in insect nerve cell membranes. The correct functioning of these channels is essential for normal transmission of nerve impulses and this process is disrupted by binding of the insecticides, leading to paralysis and eventual death. Some insect pest populations have evolved modifications of the sodium channel protein which prevent the binding of the insecticide and result in the insect developing resistance. Here we review some of the work (done at Rothamsted Research and elsewhere) that has led to the identification of specific residues on the sodium channel that may constitute the DDT and pyrethroid binding sites.

  10. In vitro and in vivo experimental data for development and use of pharmacokinetic models for in vitro to in vivo extrapolation of pyrethroid insecticides

    Science.gov (United States)

    Pyrethroids are a class of neurotoxic synthetic insecticides. Exposure to pyrethroids can be widespread because of their use in agriculture, medicine, and in residential homes and schools. Our studies are focused on generating in vitro and in vivo data for the development of phys...

  11. Relationship between bifenthrin sediment toxic units and benthic community metrics in urban California streams.

    Science.gov (United States)

    Hall, Lenwood W; Anderson, Ronald D

    2013-08-01

    The objective of this study was to use ecologically relevant field measurements for determining the relationship between bifenthrin sediment toxic units (TUs) (environmental concentrations/Hyalella acute LC50 value) and 15 benthic metrics in four urban California streams sampled from 2006 to 2011. Data from the following four California streams were used in the analysis: Kirker Creek (2006, 2007), Pleasant Grove Creek (2006, 2007, and 2008), Arcade Creek (2009, 2010, and 2011), and Salinas streams (2009, 2010, and 2011). The results from univariate analysis of benthic metrics versus bifenthrin TU calculations for the four California streams with multiple-year datasets combined by stream showed that there were either nonsignificant relationships or lack of metric data for 93 % of cases. For 7 % of the data (4 cases) where significant relationships were reported between benthic metrics and bifenthrin TUs, these relationships were ecologically meaningful. Three of these significant direct relationships were an expression of tolerant benthic taxa (either % tolerant taxa or tolerance values, which are similar metrics), which would be expected to increase in a stressed environment. These direct significant tolerance relationships were reported for Kirker Creek, Pleasant Grove Creek, and Arcade Creek. The fourth significant relationship was an inverse relationship between taxa richness and bifenthrin TUs for the 3-year Pleasant Grove Creek dataset. In summary, only a small percent of the benthic metric × bifenthrin TU relationships were significant for the four California streams. Therefore, the general summary conclusion from this analysis is that there is no strong case for showing consistent meaningful relationships between various benthic metrics used to characterize the status of benthic communities and bifenthrin TUs for these four California streams.

  12. Photodegradation of bifenthrin and deltamethrin-effect of copper amendment and solvent system.

    Science.gov (United States)

    Tariq, Saadia Rashid; Ahmed, Dildar; Farooq, Amna; Rasheed, Sonia; Mansoor, Mubarkah

    2017-02-01

    The photodegradation of bifenthrin and deltamethrin was studied in the presence of Cu salts and two different solvents, methanol and acetonitrile. Results of the study showed that in the absence of any metal salt, the two pesticides degraded more rapidly in acetonitrile than in methanol. After 24 h of UV irradiation, 70% of deltamethrin had degraded in acetonitrile, while only 41% bifenthrin degraded in this solvent. In methanol, bifenthrin degraded at a much enhanced rate than in acetonitrile while the rate of degradation of deltamethrin was comparable to that in acetonitrile. The photodegradation was further enhanced by the addition of copper to the solution of bifenthrin and deltamethrin in acetonitrile. The rate of photodegradation of deltamethrin increased from 2.4 × 10 -2 to 3.5 × 10 -2  h -1 in acetonitrile and 2.5 × 10 -2 to 3.4 × 10 -2  h -1 in methanol after the addition of copper. Similarly, the rate of photodegradation of bifenthrin was increased from 5.0 × 10 -3 to 9.0 × 10 -3  h -1 in acetonitrile and 7.0 × 10 -3 to 9.05 × 10 -3  h -1 in methanol with the addition of copper. Thus, copper has the potential to enhance the photodegradation of bifenthrin and deltamethrin in both the solvents.

  13. Microwave-assisted steam distillation for the determination of organochlorine pesticides and pyrethroids in Chinese teas.

    Science.gov (United States)

    Ji, Jie; Deng, Chunhui; Zhang, Huiqin; Wu, Yunyun; Zhang, Xiangmin

    2007-02-28

    In this work, microwave-assisted steam distillation (MASD) extraction method followed by gas chromatography/electron capture detection (GC/ECD) was developed for the determination of organochlorine pesticides (OCPs) and pyrethroids in the Chinese teas. MASD is a combination of microwave-assisted extraction (MAE) and steam distillation techniques. Water vapor generated by microwave irradiation is used to accelerate desorption of the analytes from the sample, and the nonpolar organic solvent used for trapping the analytes is kept from direct contact with the sample by the water. Therefore, relatively clean extracts were obtained compared to the method directly using organic solvent as extraction solvent, such as ultrasonic extraction (USE). Microwave power of 200W and irradiation time of 2min was found to be the optimum conditions for the MASD process, and n-heptane was chosen as the analyte-trapping solvent in the study. Five OCPs (alpha-HCH, gamma-HCH, dicofol, p,p'-DDE, p,p'-DDT) and two pyrethroids (bifenthrin, fenvalate) were determined using this extraction method in the tea samples. The relative standard deviation (R.S.D.) of the analytes varied from 2.2 to 8.4%, and the method detection limits (MDLs) found were lower than 0.23mug/kg. The recoveries of the seven compounds in the Jasmine tea sample were between 84.04 and 110.1%. Comparative results obtained by MASD and USE were also discussed in the study.

  14. Neurodevelopmental consequences of gestational and lactational exposure to pyrethroids in rats.

    Science.gov (United States)

    Syed, Farah; John, P J; Soni, Inderpal

    2016-12-01

    Indiscriminate use of pyrethroids has raised serious health related concerns, especially about their effects on children. The present study was designed to assess the developmental neurotoxicity of two pyrethroids; bifenthrin (BIF) and β-cyfluthrin (CYF) administered at 1/15 of LD 50 in rats. Pregnant females were exposed to the test compounds orally throughout gestation and lactation periods. Neonates were weighed and sexed at birth and were observed for any gross abnormality. Growth, viability and weaning indices were calculated during the lactation period. Exposure to both the compounds did not alter the physical developmental parameters viz. eye opening, pinna detachment, and fur appearance. CYF significantly impaired growth and survivability of pups. Behavioral endpoints assessed in neonates (surface righting, pivoting, and negative geotaxis reflex) as well as adults (motor activity and motor coordination) exhibited marked effect of CYF treatment. Administration of BIF to pregnant dams impaired pivoting in neonates. Decreased locomotion in the open-field and impaired rota-rod performance were also witnessed in BIF-exposed animals. Enhanced oxidative stress was seen in corpus striatum, cerebellum, and hippocampus regions of the brain; reduced catalase, superoxide dismutase, and glutathione peroxidase activities were measured in BIF and CYF treated weanlings. Acetylcholinesterase activity was also found to be lowered following administration of both compounds at PND 21. The present results suggest that exposure to pyrethroids during critical periods of growth can induce long term effects on the behavior of animals. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1761-1770, 2016. © 2015 Wiley Periodicals, Inc.

  15. Extração em fase sólida (SPE e micro extração em fase sólida (SPME de piretróides em água Solid-phase extraction (SPE and solid-phase microextraction of pyrethroids in water

    Directory of Open Access Journals (Sweden)

    Wilma Regina Barrionuevo

    2001-04-01

    Full Text Available The pyrethroids bifenthrin, permethrin, cypermethrin and deltamethrin were extracted by solid phase extraction (SPE and solid phase microextraction (SPME. The analysis were performed on a gas chromatograph with electron capture detection (GC-ECD. Octadecil Silano-C18, Florisil and Silica stationary phases were studied for SPE. Better results were obtained for Florisil which gave recoveries from 80% to 108%. Pyrethroids extraction by SPME showed a linear response and a detection limit of 10 pg ml-1. Although the data showed that the two extraction methods were able to isolate the pesticide residues from water samples, the best results were obtained by using SPME which is more sensitive, faster, cheeper, being a more useful technique for the analysis of pyrethroids in drinking water.

  16. Molecular survey of pyrethroid resistance mechanisms in Mexican field populations of Rhipicephalus (Boophilus) microplus

    Science.gov (United States)

    Susceptibility to synthetic pyrethroids (SP´s) and the role of two major resistance mechanisms were evaluated in Mexican Rhipicephalus microplus tick populations. Larval packet test (LPT), knock-down (kdr) PCR allele-specific assay (PASA) and esterase activity assays were conducted in tick populatio...

  17. Determination of pyrethroid pesticide residues in processed fruits and vegetables by gas chromatography with electron capture and mass spectrometric detection.

    Science.gov (United States)

    Sannino, Anna; Bandini, Mirella; Bolzoni, Luciana

    2003-01-01

    A gas chromatographic method was developed for the simultaneous determination of 12 pyrethroids (tefluthrin, bifenthrin, fenpropathrin, cyhalothrin, permethrin, cyfluthrin, cypermethrin, alpha-cypermethrin, flucythrinate, fenvalerate, fluvalinate, and deltamethrin) in tomato puree, peach nectar, orange juice, and canned peas. A miniaturized extraction-partition procedure requiring small amounts of nonchlorinated solvents is used. Samples are extracted with acetone, partitioned with ethyl acetate-cyclohexane (50 + 50, v/v), and cleaned up on a Florisil cartridge. The final extract is analyzed by gas chromatography with both electron capture and mass spectrometric detection modes. Studies at fortification levels of 0.010-0.100 mg/kg gave mean recoveries ranging from 70.2 to 96.0% and coefficients of variation between 4.0 and 13.9% for all compounds. Quantitation limits were < 0.010 mg/kg for electron capture detection.

  18. Occurrence and potential toxicity of pyrethroids and other insecticides in bed sediments of urban streams in central Texas

    Energy Technology Data Exchange (ETDEWEB)

    Hintzen, Emily P. [Department of Environmental Studies, Baylor University, Waco, TX 76798 (United States); Lydy, Michael J. [Fisheries and Illinois Aquaculture Center, and Department of Zoology, Southern Illinois University, Carbondale, IL 62091 (United States); Belden, Jason B. [Department of Zoology, Oklahoma State University, 430 Life Science West, Stillwater, OK 74078 (United States)], E-mail: jbelden@okstate.edu

    2009-01-15

    Despite heavy insecticide usage in urban areas, only a few studies have investigated the impact of current-use insecticides on benthic invertebrates in urban streams. The objective of this study was to measure the presence and concentration of current-use pesticides in sediments of residential streams in central Texas. Additionally, toxicity of these sediments to Hyalella azteca was evaluated. Sediment samples were collected from several sites in urban streams over the course of a year, of which, 66% had greater than one toxic unit (TU) of insecticide. Bifenthrin was the greatest contributor accounting for 65% of the TUs, and sediment toxicity to H. azteca correlated with the magnitude of total insecticides and bifenthrin TUs. The results of this study further raise concerns over the environmental consequences posed by many current-use insecticides, especially pyrethroids, in urban settings. - This study examined the presence of insecticides in Texas stream sediments as a model for evaluating the potential impact of urban insecticide use in the Southern United States.

  19. Molecular Biology of Insect Sodium Channels and Pyrethroid Resistance

    Science.gov (United States)

    Dong, Ke; Du, Yuzhe; Rinkevich, Frank; Nomura, Yoshiko; Xu, Peng; Wang, Lingxin; Silver, Kristopher; Zhorov, Boris S.

    2015-01-01

    Voltage-gated sodium channels are essential for the initiation and propagation of the action potential in neurons and other excitable cells. Because of their critical roles in electrical signaling, sodium channels are targets of a variety of naturally occurring and synthetic neurotoxins, including several classes of insecticides. This review is intended to provide an update on the molecular biology of insect sodium channels and the molecular mechanism of pyrethroid resistance. Although mammalian and insect sodium channels share fundamental topological and functional properties, most insect species carry only one sodium channel gene, compared to multiple sodium channel genes found in each mammalian species. Recent studies showed that two posttranscriptional mechanisms, alternative splicing and RNA editing, are involved in generating functional diversity of sodium channels in insects. More than 50 sodium channel mutations have been identified to be responsible for or associated with knockdown resistance (kdr) to pyrethroids in various arthropod pests and disease vectors. Elucidation of molecular mechanism of kdr led to the identification of dual receptor sites of pyrethroids on insect sodium channels. Most of the kdr mutations appear to be located within or close to the two receptor sites. The accumulating knowledge of insect sodium channels and their interactions with insecticides provides a foundation for understanding the neurophysiology of sodium channels in vivo and the development of new and safer insecticides for effective control of arthropod pests and human disease vectors. PMID:24704279

  20. Fate of Pyrethroids in Farmland Ponds

    DEFF Research Database (Denmark)

    Mogensen, B. B.; Sørensen, P. B.; Stuer-Lauridsen, F.

    Pyrethroids constitute a group of widely used insecticides, which are toxic to aquatic organisms. This report presents the results from a 2-year study of the fate of pyrethroids in ponds, i.e. their distribution in the water column, the sediment and the surface microlayer respectively....... The measurements are used to validate a distribution model and the model analysis is used for interpretation of the results. The model analysis demonstrates that pyrethroids are adsorbed in the upper few mm of the sediment...

  1. Evaluation of Bifenthrin and Acorus calamus Linn. Extract against Aedes aegypti L. and Aedes albopictus (Skuse

    Directory of Open Access Journals (Sweden)

    S Sulaiman

    2008-12-01

    Full Text Available "nBackground: Bifenthrin and Acorus calamus Linn extract were evaluated against dengue vectors in the laboratory."nMethods: Both Bifenthrin and Acorus calamus Linn crude hexane extract were bioassayed against the adults and larval stages of dengue vectors Aedes aegypti L. and Aedes albopictus(Skuse in the laboratory."nResults: The A. calamus crude hexane extract exhibited a larvicidal activity against 4th-instar Ae. aegypti larvae with LC50 and LC90 values of 0.4418 and 11.3935 ppm respectively. The plant crude extract exhibited against Ae. albopictus larvae with a higher LC50 and LC90 values of 21.2555 ppm and 36.1061 ppm, respectively. There was a significant difference on the effect of A. calamus extract on both Aedes spp. Larvae (P< 0.05. However, bifenthrin showed a significant difference on larvicidal effect to that of A. calamus hexane extract on both Aedes spp (P< 0.05. In testing the adulticidal activity, this plant extract exhibited the LC50 and LC90 values of 17.4075 and 252.9458 ppm against Ae .aegypti and a higher LC50 and LC90 values of 43.9952 and 446.1365 ppm respectively on Ae. albopictus. There was no significant difference on the effect of A. calamus extract on both Aedes spp adults (P> 0.05."nConclusion: Bifenthrin however showed a significant difference on both Aedes spp adults (P< 0.05. With the wide availability of A. calamus in Malaysia, it could be utilized for controlling dengue vectors. "n 

  2. Pyrethroids: a new threat to marine mammals?

    Science.gov (United States)

    Alonso, Mariana B; Feo, Maria Luisa; Corcellas, Cayo; Vidal, Lara G; Bertozzi, Carolina P; Marigo, Juliana; Secchi, Eduardo R; Bassoi, Manuela; Azevedo, Alexandre F; Dorneles, Paulo R; Torres, João Paulo M; Lailson-Brito, José; Malm, Olaf; Eljarrat, Ethel; Barceló, Damià

    2012-10-15

    The present study constitutes the first investigation to demonstrate pyrethroid bioaccumulation in marine mammals, despite the assumption that these insecticides are converted to non-toxic metabolites by hydrolysis in mammals. Twelve pyrethroids were determined in liver samples from 23 male franciscana dolphins from Brazil. The median concentration values for total pyrethroids were 7.04 and 68.4 ng/g lw in adults and calves, respectively. Permethrin was the predominant compound, contributing for 55% of the total pyrethroids. Results showed a distinct metabolic balance of pyrethroids through dolphin life. High loads are received at the beginning of their lives and, when they reach sexual maturity, these mammals seem to degrade/metabolize pyrethroids. Maternal transfer of these compounds was also evaluated through the analysis of breast milk and placenta samples. Pyrethroids were detected in both matrices, with values between 2.53-4.77 ng/g lw and 331-1812 ng/g lw, respectively. Therefore, for the first time, a study shows mother-to-calf transfer of pyrethroids by both gestational and lactation pathways in dolphins. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Is cumulated pyrethroid exposure associated with prediabetes?

    DEFF Research Database (Denmark)

    Hansen, Martin Rune; Jørs, Erik; Lander, Flemming

    2014-01-01

    Pyrethroids are a class of insecticides used widely for vector control programs. Acute pyrethroid poisoning is rare, but well documented, whereas effects of cumulative exposure are insufficiently described, including possible negative effect on glucose regulation. The objective of this study was ...

  4. Determination of five pyrethroids in tea drinks by dispersive solid phase extraction with polyaniline-coated magnetic particles.

    Science.gov (United States)

    Wang, Yuanpeng; Sun, Ying; Gao, Yan; Xu, Bo; Wu, Qiong; Zhang, Hanqi; Song, Daqian

    2014-02-01

    The polyaniline-coated magnetic particles with bowl-shaped morphology (Fe3O4/C/PANI microbowls) were successfully prepared and characterized by scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometry. The prepared microbowls were used as the magnetic adsorbent in dispersive solid phase extraction of five pyrethroids, including cyhalothrin, beta-cypermethrin, esfenvalerate, permethrin and bifenthrin in plain tea drinks. The effects of experiment factors, including amount of Fe3O4/C/PANI microbowls, pH value, ultrasound extraction time and desorption conditions, were investigated. The extraction recoveries obtained with 8 mg of magnetic microbowls were satisfactory, and the microbowls can be reused after easy washing. Thus, a simple, selective and effective method for the determination of the pyrethroids was established successfully. The results showed that the method had good linearity (r=0.9992-0.9998), and the limits of detections (LODs) were from 0.025 to 0.032 ng mL(-1). The intra-day and inter-day relative standard deviations (RSDs) were in the range of 2.4-6.1% and 3.5-8.8%, respectively. Recoveries obtained by analyzing the real tea drinks were in the range of 72.1-118.4%. © 2013 Published by Elsevier B.V.

  5. Identifying the cause of sediment toxicity in agricultural sediments: the role of pyrethroids and nine seldom-measured hydrophobic pesticides.

    Science.gov (United States)

    Weston, Donald P; Ding, Yuping; Zhang, Minghua; Lydy, Michael J

    2013-01-01

    Few currently used agricultural pesticides are routinely monitored for in the environment. Even if concentrations are known, sediment LC(50) values are often lacking for common sediment toxicity testing species. To help fill this data gap, sediments in California's Central Valley were tested for nine hydrophobic pesticides seldom analyzed: abamectin, diazinon, dicofol, fenpropathrin, indoxacarb, methyl parathion, oxyfluorfen, propargite, and pyraclostrobin. Most were detected, but rarely at concentrations acutely toxic to Hyalella azteca or Chironomus dilutus. Only abamectin, fenpropathrin, and methyl parathion were found at concentrations of potential concern, and only in one or two samples. One-quarter of over 100 samples from agriculture-affected waterways exhibited toxicity, and in three-fourths of the toxic samples, pyrethroids exceeded concentrations expected to cause toxicity. The pyrethroid Bi-fen-thrin in particular, as well as lambda-cyhalothrin, cypermethrin, esfenvalerate, permethrin, and the organophosphate chlorpyrifos, were primarily responsible for the observed toxicity, rather than the more novel analytes, despite the fact that much of the sampling targeted areas of greatest use of the novel pesticides. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Inter-compartmental transport of organophosphate and pyrethroid pesticides in South China: implications for a regional risk assessment.

    Science.gov (United States)

    Li, Huizhen; Wei, Yanli; Lydy, Michael J; You, Jing

    2014-07-01

    The dynamic flux of an organophosphate and four pyrethroid pesticides was determined in an air-(soil)-water-sediment system based on monitoring data from Guangzhou, China. The total air-water flux, including air-water gaseous exchange and atmospheric deposition, showed deposition from air to water for chlorpyrifos, bifenthrin and cypermethrin, but volatilization for lambda-cyhalothrin and permethrin. The transport of the pesticides from overlying water to sediment suggested that sediment acted as a sink for the pesticides. Additionally, distinct annual atmospheric depositional fluxes between legacy and current-use pesticides suggested the role of consumer usage in their transport throughout the system. Finally, pesticide toxicity was estimated from annual air-water-sediment flux within an urban stream in Guangzhou. A dynamic flux-based risk assessment indicated that inter-compartmental transport of chlorpyrifos decreased its atmospheric exposure, but had little influence on its aquatic toxicity. Instead, water-to-sediment transport of pyrethroids increased their sediment toxicity, which was supported by previously reported toxicity data. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Comparison of Methods for Bifenthrin Residues Determination in Fermented Wheat Samples

    Directory of Open Access Journals (Sweden)

    Tijana Đorđević

    2012-01-01

    Full Text Available Efficiency of three different sample preparation methods for GC/MS determinationof bifenthrin residues in wheat (Triticum spelta samples fermented by Lactobacillusplantarum was tested. The first method was based on a methanol:acetone=1:1 extractionfolowed by a purification on columns containing mixture of aluminium oxide and activatedcharcoal slurry-packed and eluted with dichlormethane, the second was based onmethanol:acetone=1:1 extraction folowed by the purification on florisil column and elutionby ethil acetate:acetone=4:1, while the third tested method was based on a combinationof the first two mentioned methods, thus methanol:acetone=1:1 extraction and clean-upthrought columns filled with a mixture of aluminum oxide and activated charcoal slurrypackedand eluted with ethil acetate:acetone=4:1. The second method was the most effectivefor obtaining satisfactory recoveries for bifenthrin in a range of 79-83% for four fortificationlevels, with good reproducibility i.e. RSD% in a range of 2.2-7.4%. The chosen methodwas further optimized by assessing the optimum volume of elution solvent used duringthe clean-up procedures. The highest recovery of 82.1% was obtained after elution with25 ml of solvent. Overall, two-step extraction with 25 ml of methanol:acetone=1:1 solventmix for 30 min, followed by clean-up procedure through a glass column with florisil coupledwith elution with 25 ml of ethyl acetate: acetone=4:1, allows simple, efficient and reliableGC/MS detection of bifenthrin residues from wheat grain fermented by L. plantarum.

  8. Environmental factors affecting efficacy of bifenthrin-treated vegetation for mosquito control.

    Science.gov (United States)

    Allan, Sandra A; Kline, Daniel L; Walker, Todd

    2009-09-01

    The use of pesticide-treated vegetation as a barrier for control of nuisance and disease-bearing mosquitoes has become an option for mosquito management for home owners and public health and mosquito control professionals. Potted wax myrtle and azalea plants were treated with bifenthrin (0.79% AI) at maximum label rate using backpack and electrostatic sprayers and exposed to various treatments that could affect the residual degradation of the applied pesticides. Treatments included leaf aspect, simulated rainfall, shade, and natural sun exposure with the residual effectiveness of leaves examined in tarsal contact Petri dish assays using laboratory-reared Aedes aegypti. There was no significant difference in efficacy between the adaxial (top) or abaxial (bottom) surfaces of electrostatically or backpack-treated leaves. Significant differences existed between application method, plant species, and exposure with most significant effects between weeks 1 and 4. Simulated heavy rainfalls applied 3 times weekly reduced knockdown by leaves treated with electrostatic and backpack methods with reductions seen as soon as 1 wk after treatment. Reductions were seen with both wax myrtle and azalea leaves and after 1, 4, and 24 h contact of mosquitoes to leaves. Placement of plants with full exposure to sunlight also significantly reduced efficacy compared to plants placed in the shade. Differences were observed most often for 4 and 24 h knockdown counts, and significant decreases were seen from week 4 onwards. Clearly factors such as rain and exposure to sun impact degradation of efficacy of bifenthrin-treated vegetation in the field. Degradation of bifenthrin efficacy was slowest in sites protected from rain and sun, which coincide with preferred resting site locations for many mosquito species.

  9. Biochemical mechanisms of organophosphate and pyrethroid resistance in red hairy caterpillar Amsacta albistriga (Lepidoptera: Arctiidae

    Directory of Open Access Journals (Sweden)

    R. Muthusamy

    2013-01-01

    Full Text Available The red hairy caterpillar, Amsacta albistriga Walker, is an important pest of groundnut, castor and cotton in India. We determined the susceptibility of Amsacta albistriga to organophosphate and synthetic pyrethroid insecticides under laboratory conditions. Biochemical profile of esterase, acetylcholinesterase, glutathione S-transferase, and glutathione S-dehydrogenase was assessed. Synthetic pyrethroid (8.82 ppm was highly toxic as compared to organophosphate insecticide (11.5 ppm: high esterase and acetylcholinesterase activity was observed in temephos treatment. GST activity was significantly higher in λ-cyhalothrin treatment. Esterase isozyme profiling using native PAGE shows inhibition of esterase bands in λ-cyhalothrin treatment, while three distinct bands (43, 66 and 70 kDa were observed in temephos and dichlorvos treatment. The results of the present study suggest that esterase and AChE are dominant organophosphate detoxification enzymes in Amsacta albistriga.

  10. Dissipation and decontamination of bifenthrin residues in tomato (Lycopersicon esculentum Mill).

    Science.gov (United States)

    Chauhan, Reena; Monga, Samriti; Kumari, Beena

    2012-07-01

    A field experiment was conducted at the Research Farm of CCS HAU, Hisar to study the dissipation and decontamination behavior of bifenthrin on tomato crop following the application of 25 g a.i ha(-1) (T(1)) and 50 g a.i ha(-1) (T(2)). Samples were collected periodically on the sampling days after applications. Residues were reached below detectable level of 0.005 mg kg(-1) on 10(th) day after application showing half-life period of 1.83 and 2.05 days at room temperature and 2.02 and 2.32 days under refrigerated condition for single and double dose, respectively. Processing was found effective in reducing the residues of bifenthrin in tomato fruits. Maximum reduction (42.10-45.23 %) was observed by washing + boiling followed by washing (16.66-19.04 %). Reduction was slightly less when samples were stored under refrigerated conditions as compared to room temperature conditions.

  11. Development of Candidate Reference Materials of Endosulfan Sulfate and Bifenthrin in Black Tea

    Directory of Open Access Journals (Sweden)

    Nurhani Aryana

    2016-03-01

    Full Text Available The candidate reference materials of endosulfan sulfate and bifenthrin in black tea have been developed according to the requirements of ISO Guide 34 and 35. Preparation of candidate material includes grinding and sieving of the black tea leaves, spiking the black tea powder by both analytes, homogenization, and bottling. Homogeneity and short-term stability test were performed using a GC-µECD instrument. Meanwhile, the characterization was carried out by a collaborative study using both of GC-µECD and GC-MS instruments. The uncertainty budget was evaluated from sample inhomogeneity, short-term instability and variability in the characterization procedure. In a dry mass fraction, endosulfan sulfate was assigned to be 491 µg kg-1 with a relative expanded uncertainty of ± 33.2%, and bifenthrin was assigned to be 937 µg kg-1 with a relative expanded uncertainty of ± 18.5%. The candidate reference materials are aimed to support the need of matrix CRM especially for the measurement of pesticide residue for quality assurance work done by laboratories in Indonesia.

  12. Susceptibility of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) to pyrethroids and their associations in Pernambuco, Brazil.

    Science.gov (United States)

    de Santana, Breno Barros; Ramos, Rafael Antonio Nascimento; Santana, Marília de Andrade; Alves, Leucio Cãmara; de Carvalho, Gílcia Aparecida

    2013-01-01

    The synthetic pyrethroids and their associations have been widely used for controlling Rhipicephalus (Boophilus) microplus. The frequent use of acaricides has been inducing the development of resistance in the tick populations. The aim of this study was to assess the susceptibility of R. (B.) microplus populations to pyrethroids and their associations in the region of Garanhuns, Pernambuco, Brazil. In addition, the level of information among farm owners regarding tick control measures was investigated. Ticks were collected directly from naturally infested dairy cattle in the region and were exposed to pyrethroids and their associations. At the same time, an epidemiological questionnaire was applied with the aim of investigating the level of information among the farmers. The results reported here indicate that R. (B.) microplus populations in the dairy region of Garanhuns show resistance to pyrethroids and their associations, except when the product is associated with piperonyl butoxide. Regarding the results from the epidemiological survey, it was seen that there is a considerable lack of information among the farmers in relation to ixodid control measures. The level of ticks resistance to acaricides varied widely across the region studied. No alternative control programs have been implemented among these farms, thus demonstrating that there is a need for more information relating to the biology and control of R. (B.) microplus.

  13. Pyrethroid receptor in the insect Na sup + channel: Alteration of its properties in pyrethroid-resistant flies

    Energy Technology Data Exchange (ETDEWEB)

    Pauron, D.; Barhanin, J.; Amichot, M.; Pralavorio, M.; Berge, J.B.; Lazdunski, M. (Centre National de la Recherche Scientifique, Nice (France))

    1989-02-21

    Resistance to insecticides is a major problem in agriculture. ({sup 3}H)Saxitoxin binding experiments have shown that pyrethroid-sensitive and pyrethroid-resistant flies have the same amount of Na{sup +} channel protein in their brain membranes. Also, although flies are resistant to pyrethroids, they remain as sensitive to batrachotoxin, which is another type of Na{sup +} channel activators, as pyrethroid-sensitive flies. Pyrethroid binding sites have been characterized by use of the properties of pyrethroids to increase the specific ({sup 3}H)batrachotoxinin A 20{alpha}-benzoate binding component. K{sub 0.5} values for association of pyrethroids at the Na{sup +} channel of pyrethroid-sensitive flies are in the range of 0.15-0.25 {mu}M. Conversely, pyrethroids do not produce a significant increase of ({sup 3}H)batrachotoxinin A 20{alpha}-benzoate binding in pyrethroid-resistant flies even at high concentrations of the insecticide. It is concluded that linkage between pyrethroid and batrachotoxin binding sites is altered in the pyrethroid-resistant fly strains. This alteration is probably due to a drastically decreased affinity of the Na{sup +} channel for pyrethroids.

  14. Desorption of pyrethroids from suspended solids.

    Science.gov (United States)

    Fojut, Tessa L; Young, Thomas M

    2011-08-01

    Pyrethroid insecticides have been widely detected in sediments at concentrations that can cause toxicity to aquatic organisms. Desorption rates play an important role in determining the bioavailability of hydrophobic organic compounds, such as pyrethroids, because these compounds are more likely to be sorbed to solids in the environment, and times to reach sorptive equilibrium can be long. In the present study, sequential Tenax desorption experiments were performed with three sorbents, three aging times, and four pyrethroids. A biphasic rate model was fit to the desorption data with r(2)  > 0.99, and the rapid and slow compartment desorption rate constants and compartment fractions are reported. Suspended solids from irrigation runoff water collected from a field that had been sprayed with permethrin 1 d before were used in the experiments to compare desorption rates for field-applied pyrethroids with those for laboratory-spiked materials. Suspended solids were used in desorption experiments because suspended solids can be a key source of hydrophobic compounds in surface waters. The rapid desorption rate parameters of field-applied permethrin were not statistically different from those of laboratory spiked permethrin, indicating that desorption of the spiked pyrethroids is comparable to desorption of the pyrethroids added and aged in the field. Sorbent characteristics had the greatest effect on desorption rate parameters; as organic carbon content of the solids increased, the rapid desorption fractions and rapid desorption rate constants both decreased. The desorption rate constant of the slow compartment for sediment containing permethrin aged for 28 d was significantly different compared to aging for 1 d and 7 d, whereas desorption in the rapid and slow compartments did not differ between these treatments. Copyright © 2011 SETAC.

  15. Towards an identification of the pyrethroid pharmacophore. A molecular modelling study of some pyrethroid esters

    DEFF Research Database (Denmark)

    Byberg, J R; Jørgensen, Flemming Steen; Klemmensen, P D

    1987-01-01

    A molecular modelling and computer graphics study of a series of pyrethroid insecticides has been carried out. The three-dimensional arrangement of the groups essential for the biological activity (pharmacophore) has been identified for the acid and the alcohol moieties, respectively. These pharm......A molecular modelling and computer graphics study of a series of pyrethroid insecticides has been carried out. The three-dimensional arrangement of the groups essential for the biological activity (pharmacophore) has been identified for the acid and the alcohol moieties, respectively....... These pharmacophores are based on the relationship between molecular structure and biological activity for a number of pyrethroid esters. The pharmacophores, which describe the relative location in space of the unsaturated systems, the dimethyl groups and the ester moiety, may be useful in the design of novel...... compounds with pyrethroid activity....

  16. Evaluation of a New Spraying Machine for Barrier Treatment and Penetration of Bifenthrin on Vegetation Against Mosquitoes

    Science.gov (United States)

    2015-03-01

    vegetation against adult Aedes albopictus and Culex quinquefasciatus in screened field cages. J Am Mosq Control Assoc 24:263–269. Doyle MA, Kline DL, Allan...Applications of insecticides to plant foliage are an effective tool in operational mosquito control (Amoo et al. 2008, Xue 2008, Qualls et al. 2013) and can...apply bifenthrin for mosquito control barrier treatments (Allan et al. 2009, Britch et al. 2009, Hoffmann et al. 2009, Farooq et al. 2010, Qualls et al

  17. counter pyrethroid insecticide product in Nigeria

    African Journals Online (AJOL)

    We evaluated the brain, lung, and heart oxidative stress in rats exposed to aerosol of an over-thecounter pyrethroid insecticide product in Nigeria. The experimental animals were randomly divided into four groups: group I (control) was not exposed to the insecticide aerosol, while groups II, III, and IV were exposed to 6.0 mL ...

  18. Physical conditions affecting pyrethroid toxicity in arthropods

    NARCIS (Netherlands)

    Jagers op Akkerhuis, G.

    1993-01-01

    The aim of this thesis was to obtain mechanistic information about how the toxicity of pesticides in the field is affected by physical factors, pesticide bioavailability and arthropod behaviour. The pyrethroid insecticide deltamethrin and linyphiid spiders were selected as pesticide-effect

  19. Behavioral effects of type II pyrethroid cyhalothrin in rats

    International Nuclear Information System (INIS)

    Righi, D. Abbud; Palermo-Neto, J.

    2003-01-01

    Synthetic pyrethroids such as cyhalothrin are extensively used in agriculture for the control of a broad range of ectoparasites in farm animals. It has been suggested that type II pyrethroids might induce anxiogenic-like effects in laboratory animals. The present study was undertaken to investigate a possible anxiogenic-like outcome of cyhalothrin in rats. Adult male rats were orally dosed for 7 days with 1.0, 3.0, or 7.0 mg/kg/day of cyhalothrin, present in a commercial formulation (Grenade Coopers do Brazil S.A.). The neurobehavioral changes induced by cyhalothrin as well as those produced on corticosterone serum levels were measured 24 h after the last treatment. Picrotoxin (1.0 mg/kg) was also acutely used as a positive control for anxiety. Results showed that cyhalothrin: (1) induced some signs and symptoms of intoxication that included salivation, tremors, and liquid feces; (2) reduced total locomotor activity in the open-field; (3) reduced the percentage of time spent in open-field central zones; (4) increased immobility time in the open-field; (5) reduced the percentage of time spent in plus-maze open arms exploration; (6) reduced the time spent in social interactions, and (7) increased the levels of serum corticosterone. The behavioral changes reported for cyhalothrin (3.0 mg/kg/day) were similar of those induced by picrotoxin. The no effect level dose obtained for cyhalothrin in this study was 1.0 mg/kg/day. These results provide experimental evidence that cyhalothrin induces anxiety-like symptoms, with this effect being dose-related. Thus, anxiety must be included among the several signs and symptoms of pesticide intoxication

  20. Mutation in the Sodium Channel Gene Corresponds With Phenotypic Resistance of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) to Pyrethroids.

    Science.gov (United States)

    Klafke, G M; Miller, R J; Tidwell, J; Barreto, R; Guerrero, F D; Kaufman, P E; Pérez de León, A A

    2017-11-07

    The brown dog tick, Rhipicephalus sanguineus sensu lato (Latreille), is a cosmopolitan ectoparasite and vector of pathogens that kill humans and animals. Pyrethroids represent a class of synthetic acaricides that have been used intensely to try to control the brown dog tick and mitigate the risk of tick-borne disease transmission. However, acaricide resistance is an emerging problem in the management of the brown dog tick. Understanding the mechanism of resistance to acaricides, including pyrethroids, is important to adapt brown dog tick control strategies. The main objective of this study was to determine if target-site mutations associated with pyrethroid resistance in other pests could be associated with phenotypic resistance detected in a brown dog tick population from Florida. We amplified segment 6 of the domain III of the voltage-sensitive sodium channel protein, using cDNAs synthesized from pyrethroid-susceptible and pyrethroid-resistant tick strains. A single nucleotide point mutation (SNP) identified in a highly conserved region of domain III S6 in the resistant ticks resulted in an amino acid change from phenylalanine to leucine. This mutation is characteristic of resistance phenotypes in other tick species, and is the first report of this mutation in R. sanguineus. Molecular assays based on this knowledge could be developed to diagnose the risk for pyrethroid resistance, and to inform decisions on integrated brown dog tick management practices. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Toxicological effects of pyrethroids on non-target aquatic insects.

    Science.gov (United States)

    Antwi, Frank B; Reddy, Gadi V P

    2015-11-01

    The toxicological effects of pyrethroids on non-target aquatic insects are mediated by several modes of entry of pyrethroids into aquatic ecosystems, as well as the toxicological characteristics of particular pyrethroids under field conditions. Toxicokinetics, movement across the integument of aquatic insects, and the toxicodynamics of pyrethroids are discussed, and their physiological, symptomatic and ecological effects evaluated. The relationship between pyrethroid toxicity and insecticide uptake is not fully defined. Based on laboratory and field data, it is likely that the susceptibility of aquatic insects (vector and non-vector) is related to biochemical and physiological constraints associated with life in aquatic ecosystems. Understanding factors that influence aquatic insects susceptibility to pyrethroids is critical for the effective and safe use of these compounds in areas adjacent to aquatic environments. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  2. Sodium Channel Mutations and Pyrethroid Resistance in Aedes aegypti

    Directory of Open Access Journals (Sweden)

    Yuzhe Du

    2016-10-01

    Full Text Available Pyrethroid insecticides are widely used to control insect pests and human disease vectors. Voltage-gated sodium channels are the primary targets of pyrethroid insecticides. Mutations in the sodium channel have been shown to be responsible for pyrethroid resistance, known as knockdown resistance (kdr, in various insects including mosquitoes. In Aedes aegypti mosquitoes, the principal urban vectors of dengue, zika, and yellow fever viruses, multiple single nucleotide polymorphisms in the sodium channel gene have been found in pyrethroid-resistant populations and some of them have been functionally confirmed to be responsible for kdr in an in vitro expression system, Xenopus oocytes. This mini-review aims to provide an update on the identification and functional characterization of pyrethroid resistance-associated sodium channel mutations from Aedes aegypti. The collection of kdr mutations not only helped us develop molecular markers for resistance monitoring, but also provided valuable information for computational molecular modeling of pyrethroid receptor sites on the sodium channel.

  3. Validation of a Rapid and Sensitive UPLC-MS-MS Method Coupled with Protein Precipitation for the Simultaneous Determination of Seven Pyrethroids in 100 µL of Rat Plasma by Using Ammonium Adduct as Precursor Ion.

    Science.gov (United States)

    Singh, Sheelendra Pratap; Dwivedi, Nistha; Raju, Kanumuri Siva Rama; Taneja, Isha; Wahajuddin, Mohammad

    2016-04-01

    United States Environmental Protection Agency has recommended estimating pyrethroids' risk using cumulative exposure. For cumulative risk assessment, it would be useful to have a bioanalytical method for quantification of one or several pyrethroids simultaneously in a small sample volume to support toxicokinetic studies. Therefore, in the present study, a simple, sensitive and high-throughput ultraperformance liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous analysis of seven pyrethroids (fenvalerate, fenpropathrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, cypermethrin and deltamethrin) in 100 µL of rat plasma. A simple single-step protein precipitation method was used for the extraction of target compounds. The total chromatographic run time of the method was 5 min. The chromatographic system used a Supelco C18 column and isocratic elution with a mobile phase consisting of methanol and 5 mM ammonium formate in the ratio of 90 : 10 (v/v). Mass spectrometer (API 4000) was operated in multiple reaction monitoring positive-ion mode using the electrospray ionization technique. The calibration curves were linear in the range of 7.8-2,000 ng/mL with correlation coefficients of ≥ 0.99. All validation parameters such as precision, accuracy, recovery, matrix effect and stability met the acceptance criteria according to the regulatory guidelines. The method was successfully applied to the toxicokinetic study of cypermethrin in rats. To the best of our knowledge, this is the first LC-MS-MS method for the simultaneous analysis of pyrethroids in rat plasma. This validated method with minimal modification can also be utilized for forensic and clinical toxicological applications due to its simplicity, sensitivity and rapidity. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Advances in the mode of action of pyrethroids.

    Science.gov (United States)

    Clark, J Marshall; Symington, Steven B

    2012-01-01

    The ability to clone, express, and electrophysiologically measure currents carried by voltage-gated ion channels has allowed a detailed assessment of the action of pyrethroids on various target proteins.Recently, the heterologous expression of various rat brain voltage-gated sodium channel isoforms in Xenopus laevis oocytes has determined a wide range of sensitivities to the pyrethroids, with some channels virtually insensitive and others highly sensitive. Furthermore, some isoforms show selective sensitivity to certain pyrethroids and this selectivity can be altered in a state-dependent manner. Additionally, some rat brain isoforms are apparently more sensitive to pyrethroids than the corresponding human isoform. These finding may have significant relevance in judging the merit and value of assessing the risk of pyrethroid exposures to humans using toxicological studies done in rat.Other target sites for certain pyrethroids include the voltage-gated calcium and chloride channels. Of particular interest is the increased effect of Type II pyrethroids on certain phosphoforms of the N-type Ca(v)2.2 calcium channel following post-translational modification and its relationship to enhanced neurotransmitter release seen in vivo.Lastly, parallel neurobehavioral and mechanistic studies on three target sites suggest that a fundamental difference exists between the action of Types I and II pyrethroids, both on a functional and molecular level. These differences should be considered in any future risk evaluation of the pyrethroids.

  5. Neurological Deficits After Long-term Pyrethroid Exposure

    DEFF Research Database (Denmark)

    Hansen, Martin Rune Hassan; Jørs, Erik; Lander, Flemming

    2017-01-01

    Pyrethroid pesticides have been suggested to be a cause of Parkinson disease and other neurodegenerative diseases. To investigate this, a cross-sectional study was conducted among 120 Bolivian public health vector program spray men, primarily exposed to pyrethroids. Pesticide exposure and central...... quintile = -0.405 [-0.660 to -0.150]), and workers only exposed to pyrethroids performed worse than workers also exposed to other pesticides (adjusted β = -1.344 [-2.224 to -0.464]). Chronic pyrethroid exposure may cause deterioration in neurocognitive performance, and exposure control is recommended....

  6. Novel Mutations in the Voltage-Gated Sodium Channel of Pyrethroid-Resistant Varroa destructor Populations from the Southeastern USA.

    Directory of Open Access Journals (Sweden)

    Joel González-Cabrera

    Full Text Available The parasitic mite Varroa destructor has a significant worldwide impact on bee colony health. In the absence of control measures, parasitized colonies invariably collapse within 3 years. The synthetic pyrethroids tau-fluvalinate and flumethrin have proven very effective at managing this mite within apiaries, but intensive control programs based mainly on one active ingredient have led to many reports of pyrethroid resistance. In Europe, a modification of leucine to valine at position 925 (L925V of the V. destructor voltage-gated sodium channel was correlated with resistance, the mutation being found at high frequency exclusively in hives with a recent history of pyrethroid treatment. Here, we identify two novel mutations, L925M and L925I, in tau-fluvalinate resistant V. destructor collected at seven sites across Florida and Georgia in the Southeastern region of the USA. Using a multiplexed TaqMan® allelic discrimination assay, these mutations were found to be present in 98% of the mites surviving tau-fluvalinate treatment. The mutations were also found in 45% of the non-treated mites, suggesting a high potential for resistance evolution if selection pressure is applied. The results from a more extensive monitoring programme, using the Taqman® assay described here, would clearly help beekeepers with their decision making as to when to include or exclude pyrethroid control products and thereby facilitate more effective mite management programmes.

  7. Novel Mutations in the Voltage-Gated Sodium Channel of Pyrethroid-Resistant Varroa destructor Populations from the Southeastern USA

    Science.gov (United States)

    González-Cabrera, Joel; Rodríguez-Vargas, Sonia; Davies, T. G. Emyr; Field, Linda M.; Schmehl, Daniel; Ellis, James D.; Krieger, Klemens; Williamson, Martin S.

    2016-01-01

    The parasitic mite Varroa destructor has a significant worldwide impact on bee colony health. In the absence of control measures, parasitized colonies invariably collapse within 3 years. The synthetic pyrethroids tau-fluvalinate and flumethrin have proven very effective at managing this mite within apiaries, but intensive control programs based mainly on one active ingredient have led to many reports of pyrethroid resistance. In Europe, a modification of leucine to valine at position 925 (L925V) of the V. destructor voltage-gated sodium channel was correlated with resistance, the mutation being found at high frequency exclusively in hives with a recent history of pyrethroid treatment. Here, we identify two novel mutations, L925M and L925I, in tau-fluvalinate resistant V. destructor collected at seven sites across Florida and Georgia in the Southeastern region of the USA. Using a multiplexed TaqMan® allelic discrimination assay, these mutations were found to be present in 98% of the mites surviving tau-fluvalinate treatment. The mutations were also found in 45% of the non-treated mites, suggesting a high potential for resistance evolution if selection pressure is applied. The results from a more extensive monitoring programme, using the Taqman® assay described here, would clearly help beekeepers with their decision making as to when to include or exclude pyrethroid control products and thereby facilitate more effective mite management programmes. PMID:27191597

  8. Pyrethroid as a Substance of Abuse

    Directory of Open Access Journals (Sweden)

    Pravesh Sharma

    2014-01-01

    Full Text Available This is a case of a 22-year-old Hispanic male with a history of bipolar disorder and methamphetamine dependence who was admitted after presenting with suicidal ideations by slashing his throat with a machete. The patient had been smoking and inhaling “processed” pyrethroid for about eight weeks as an inexpensive methamphetamine substitute. He reported experiencing a “rush” similar to methamphetamine after using pyrethroid from liquid insecticide that had been heated (electrocuted or sprayed on hot metal sheets until it crystallized. The patient presented with no significant physical markings or findings but claimed to have his suicidal ideations precipitated by concerns of ill effects of pyrethroid on his health. He also had positive urine drug screen for methamphetamine, which he admitted to using on the day of admission. We conclude that it is important for physicians to maintain a high level of suspicion for alternate and uncommon substances of abuse as well as risks for suicidal tendencies in these patients.

  9. Pharmacokinetics of a pyrethroid insecticide mixture in the rat

    Science.gov (United States)

    Pyrethroid insecticides are used and co-occur in the environment, in residences and day care facilities. Pharmacokinetic models of pyrethroids and assessment of risk from their exposure would be better informed if data are derived from studies using chemical mixtures. The objecti...

  10. EFFECTS OF ACUTE PYRETHROID EXPOSURE ON THERMOREGULATION IN RATS.

    Science.gov (United States)

    Pyrethroid insecticides produce acute neurotoxicity in mammals. According to the FQPA mandate, the USEPA is required to consider the risk of cumulative toxicity posed to humans through exposure to pyrethroid mixtures. Thermoregulatory response (TR) is being used to determine if t...

  11. Neurological Deficits After Long-term Pyrethroid Exposure

    DEFF Research Database (Denmark)

    Hassan Hansen, Martin Rune; Jørs, Erik; Lander, Flemming

    2017-01-01

    Pyrethroid pesticides have been suggested to be a cause of Parkinson disease and other neurodegenerative diseases. To investigate this, a cross-sectional study was conducted among 120 Bolivian public health vector program spray men, primarily exposed to pyrethroids. Pesticide exposure and central...

  12. Copper clean-up procedure for ultrasonic extraction and analysis of pyrethroid and phenylpyrazole pesticides in sediments by gas chromatography-electron capture detection.

    Science.gov (United States)

    Wu, Jun; Lin, Youjian; Lu, Jian; Wilson, Chris

    2011-08-15

    A rapid ultrasonic extraction method coupled with a heated-copper clean-up procedure for removing interfering constituents was developed for analyzing pyrethroid and phenylpyrazole pesticides in sediments. Incubation of the 60 mL extract with 12 g copper granules at 60 °C for 2h was determined to be the optimal conditions for removing the interfering constituents. Eleven pyrethroid and phenylpyrazole pesticides were spiked into sediment samples to determine the effectiveness of the ultrasonic extraction method. The average recoveries of pyrethroids and phenylpyrazoles in sediment at 4 °C storage on day 0, 1, 7, 14, and 21 ranged from 98.6 to 120.0%, 79.2 to 116.0%, 85.0 to 119.7%, 93.6 to 118.7%, and 92.1 to 118.2%, respectively, with all percent relative standard deviations less than 10% (most <6%). This illustrated the stability of pyrethroids and phenylpyrazoles in sediment during sediment aging at 4 °C. Recoveries of the pesticides ranged from 98.6% to 120.0% for lowest fortification level (2-16 μg kg⁻¹), from 97.8% to 117.9% for middle fortification level (10-80 μg kg⁻¹), and from 94.3% to 118.1% for highest fortification level (20-160 μg kg⁻¹). Relative standard deviations of pesticide recoveries were usually less than 7%. Method detection limits of target pesticides ranged from 0.22 μg kg⁻¹ to 3.72 μg kg⁻¹. Furthermore, field sediment samples collected from four residential lakes during a three-month monitoring period were analyzed to evaluate the effectiveness of this method. Bifenthrin was detected in all of sediment samples (highest concentration 260.33±41.71 μg kg⁻¹, lowest concentration 5.68±0.38 μg kg⁻¹, and fipronil sulfone was detected at least once in sediment samples collected from three sites with concentrations ranging from 1.73±0.53 to 7.53±0.01 μg kg⁻¹. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Determination of seven pyrethroids and six pyrethrins in water by liquid chromatography/mass spectrometry

    Science.gov (United States)

    ccanccapa, alexander; Masia, Ana; Pico, Yolanda

    2016-04-01

    Pyrethroids are the synthetic analogues of pyrethrins which were developed as pesticides from the extracts of dried and powdered flower heads of Chrysanthemum cinerariaefolium. They are increasingly used in agriculture due to their broad biological activity and slow development of pest resistance. Contamination of fresh-water ecosystems appears either because of the direct discharge of industrial and agricultural effluents or as a result of effluents from sewage treatment works; residues can thus accumulate in the surrounding biosphere [1, 2]. These substances, mostly determined by gas chromatography mass spectrometry (GC-MS) can be difficult to analyse due to their volatility and degradability. The purpose of this study is, as an alternative, to develop a fast and sensitive multi-residue method for the target analysis of 7 pyrethroids and the 6 natural pyrethrins currently used in water samples by liquid chromatography tandem mass spectrometry (LC-MS/MS). The compounds included in the study were acrinathrin, etofenprox, cyfluthrin, esfenvalerate, cyhalothrin, cypermethrin and flumethrin as pyrethroids and a commercial mix of pyrethrins containing Cinerin I, Jasmolin I, pyrethrin I, cinerin II, jasmolin II, pyrethrins II in different percentages. As a preliminary step, the ionization and fragmentation of the compounds were optimized injecting individual solutions of each analyte at 10 ppm in the system, using a gradient elution profile of water-methanol both with 10 mM ammonium formate. The ESI conditions were: capillary voltage 4000 V, nebulizer15 psi, source temperature 300◦C and gas flow 10 L min-1. [M+H]+, [M+Na]+ ,[M+NH3]+ ,[M+NH4+]+ were tested as precursor ions. The most intense signal was for ammonium adduct for all compounds. The optimal fragmentor range for product ions were between 20 to 80 ev and the collision energy ranged between 5 to 86 ev. The efficiency of the method was tested in water samples from Turia River without any known exposure to

  14. Degradation of bifenthrin and pirimiphos-methyl residues in stored wheat grains (Triticum aestivum L.) by ozonation.

    Science.gov (United States)

    Savi, Geovana D; Piacentini, Karim C; Bortolotto, Tiago; Scussel, Vildes M

    2016-07-15

    Pesticide insecticides are used on wheat grains in storage units but their efficiency is hindered by persistent residues in the grains. Therefore, this study aims to evaluate the effectiveness of ozone (O3) gas treatment on the degradation of residual bifenthrin and pirimiphos-methyl insecticides commonly used in storage wheat grains, as well as to evaluate degradation of their by-products. The residues of bifenthrin decreased after 180 min of exposure in a concentration of 60 μmol/mol (a 37.5 ± 7.4% reduction) with 20% moisture content and 0.9 water activity. On the other hand, under the same experimental conditions, the pirimiphos-methyl residues significantly decreased in the wheat grains (71.1 ± 8.6%) after 30 min of exposure. After O3 gas treatment, three by-products of pirimiphos-methyl (m/z=306.1) containing different molecular mass to charge ratios (m/z=278.1, 301.1 and 319.2) were identified by LC-MS. O3 is a strong oxidizer that has shown the potential to reduce pesticide residues in stored grain in order to ensure food quality and safety. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Analysis of metabolites of organophosphate and pyrethroid pesticides in human urine from urban and agricultural populations (Catalonia and Galicia).

    Science.gov (United States)

    Garí, Mercè; González-Quinteiro, Yolanda; Bravo, Natalia; Grimalt, Joan O

    2018-05-01

    Isotope dilution solid phase extraction UPLC-MS/MS has been used to develop a robust and rapid methodology for the determination of eight specific metabolites of organophosphate and pyrethroid pesticides in human urine. The use of methanol:acetone (25:75v/v) affords an improvement in extraction efficiency in comparison to these individual solvents. The use of synthetic urine improves selectivity and limits of detection for the calibration straight lines. The method provides detection limits of 14-69pg/ml and 18-19pg/ml for the organophosphate and pyrethroid metabolites, respectively. Urine analyses of these metabolites in urban non-occupationally exposed individuals and farm workers shows that ingestion of these pesticides occurred in both populations. The concentrations of organophosphate pesticide metabolites in the latter were twofold than those from non-exposed populations. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Validation of a Rapid and Sensitive UPLC–MS-MS Method Coupled with Protein Precipitation for the Simultaneous Determination of Seven Pyrethroids in 100 µL of Rat Plasma by Using Ammonium Adduct as Precursor Ion

    Science.gov (United States)

    Singh, Sheelendra Pratap; Dwivedi, Nistha; Raju, Kanumuri Siva Rama; Taneja, Isha; Wahajuddin, Mohammad

    2016-01-01

    United States Environmental Protection Agency has recommended estimating pyrethroids’ risk using cumulative exposure. For cumulative risk assessment, it would be useful to have a bioanalytical method for quantification of one or several pyrethroids simultaneously in a small sample volume to support toxicokinetic studies. Therefore, in the present study, a simple, sensitive and high-throughput ultraperformance liquid chromatography–tandem mass spectrometry method was developed and validated for simultaneous analysis of seven pyrethroids (fenvalerate, fenpropathrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, cypermethrin and deltamethrin) in 100 µL of rat plasma. A simple single-step protein precipitation method was used for the extraction of target compounds. The total chromatographic run time of the method was 5 min. The chromatographic system used a Supelco C18 column and isocratic elution with a mobile phase consisting of methanol and 5 mM ammonium formate in the ratio of 90 : 10 (v/v). Mass spectrometer (API 4000) was operated in multiple reaction monitoring positive-ion mode using the electrospray ionization technique. The calibration curves were linear in the range of 7.8–2,000 ng/mL with correlation coefficients of ≥0.99. All validation parameters such as precision, accuracy, recovery, matrix effect and stability met the acceptance criteria according to the regulatory guidelines. The method was successfully applied to the toxicokinetic study of cypermethrin in rats. To the best of our knowledge, this is the first LC–MS-MS method for the simultaneous analysis of pyrethroids in rat plasma. This validated method with minimal modification can also be utilized for forensic and clinical toxicological applications due to its simplicity, sensitivity and rapidity. PMID:26801239

  17. Automated solid-phase extraction coupled to gad chromatography with electron-capture detection: a combinatiton of extraction and clean-up of pyrethroids in the analysis of surface water.

    NARCIS (Netherlands)

    van der Hoff, G.R.; Pelusio, F.; Brinkman, U.A.T.; Baumann, R.A.; van Zoonen, P.

    1996-01-01

    The combination of automated solid-phase extraction (SPE) and large-volume introduction gas chromatography electron-capture detection (GC-ECD) is used for the determination of synthetic pyrethroids in surface and drinking water. The selectivity that is needed for the use of GC-ECD of environmental

  18. Field Study of the Comparative Efficacy of Three Pyrethroid/Neonicotinoid Mixture Products for the Control of the Common Bed Bug, Cimex lectularius

    Directory of Open Access Journals (Sweden)

    Changlu Wang

    2015-03-01

    Full Text Available Three insecticide mixtures that contain two classes of insecticides (pyrethroid and neonicotinoid were recently developed to control bed bugs. We evaluated three integrated bed bug management strategies in apartments, each using the same non-chemical control methods and one of the three insecticide mixture products: Tandem (lambda-cyhalothrin + thiamethoxam, Temprid SC (beta-cyfluthrin + imidacloprid, and Transport Mikron (bifenthrin + acetamiprid. No insecticides were applied in the Control apartments. In all apartments, we installed vinyl mattress encasements (if not already present and applied steam to beds and other infested upholstered furniture. Insecticide sprays were applied in the three treatments. Each treatment and the Control included 8–10 occupied apartments. Re-treatment was conducted during biweekly inspections if necessary. After eight weeks, the mean (± SEM bed bug count reduction in the Tandem, Temprid SC, Transport Mikron, and Control was 89 ± 9, 87 ± 6, 98 ± 1, and 23 ± 54%, respectively. Only Tandem and Transport Mikron treatments resulted in significantly higher population reduction than the Control at eight weeks. There were no significant differences in mean percent reduction among the three treatments (Tandem, Temprid SC, Transport Mikron at eight weeks. Tandem spray caused significantly faster bed bug reduction than Temprid SC spray and Transport Mikron spray.

  19. Relative potencies of Type I and Type II pyrethroids for inhibition of spontaneous firing in neuronal networks.

    Science.gov (United States)

    Pyrethroids insecticides commonly used in pest control disrupt the normal function of voltage-sensitive sodium channels. We have previously demonstrated that permethrin (a Type I pyrethroid) and deltamethrin (a Type II pyrethroid) inhibit sodium channel-dependent spontaneous netw...

  20. Transcriptional response of rat cerebrocortical tissue following acute in vivo exposure to the pyrethroid insecticides permethrin and deltamethrin

    Science.gov (United States)

    Pyrethroids are neurotoxic pesticides that interact with membrane bound ion channels in neurons. The physiological result is disruption of nerve membrane excitability. A current focus of pyrethroid research is examination of the molecular mechanisms-of-action of pyrethroids, in...

  1. Evidence for effects on thermoregulation after acute oral exposure to type I and type II pyrethroids in infant rats.

    Science.gov (United States)

    Bardullas, Ulises; Sosa-Holt, Carla Solange; Pato, Alejandro Martín; Nemirovsky, Sergio Iván; Wolansky, Marcelo Javier

    2015-01-01

    Most pyrethroid (PYR) insecticides may be classified either as type-I compounds, which produce whole body tremors and hyperthermia, or type-II compounds, which produce salivation, choreoathetosis, and hypothermia (i.e., producing T and CS neurobehavioral syndromes, respectively). This classification is based on clinical observations in adult rats and mice after intracerebroventricular or intravascular administration of highly effective acute (bolus) doses. PYR neurotoxicity in infant animals is not characterized as much as in adult animals. Endpoints informing on vital determinants of mammal's maturation, such as body temperature may help recognizing age-related differences in susceptibility to PYRs. In this work, body temperature (Tb) was monitored at 30-min intervals after acute oral exposure to T-syndrome PYR bifenthrin (BIF), CS-syndrome PYR cypermethrin (CYPM), and a BIF–CYPM mixture in weanling rats by using a subcutaneous temperature monitoring system. In both single-compound assays, a time- and dose-related decline of Tb was the most evident impact on thermoregulation observed starting at ~2–3 h after dosing.Moreover, 15–18 mg/kg BIF induced a mild increase in Tb before the hypothermic action was apparent. The lowest effective dose for temperature perturbation was 15mg/kg for BIF and 10mg/kg for CYPM, and moderate neurobehavioral alterations were evident at 12 and 10mg/kg, respectively. When low effective doses of BIF and CYPM were co-administered mild behavioral effects and a transient increase in Tb (p=0.02) were observed at 1–2 h, and no Tb decline was apparent afterwards compared to control animals. Noteworthy, the hypothermic action of BIF in infant rats was quite different from the hyperthermia consistently reported in studies using mature animals. Our results suggest that body temperature monitoring may be useful as a complementary assessment to reveal qualitative age-specific pesticide effects in rats.

  2. Neurotoxicological effects and the mode of action of pyrethroid insecticides

    NARCIS (Netherlands)

    Vijverberg, H.P.M.; Bercken, Joep van den

    1990-01-01

    Neuroexcitatory symptoms of acute poisoning of vertebrates by pyrethroids are related to the ability of these insecticides to modify electrical activity in various parts of the nervous system. Repetitive nerve activity, particularly in the sensory nervous system, membrane depolarization, and

  3. MSPD procedure combined with GC-MS for the determination of procymidone, bifenthrin, malathion and pirimicarb in honey

    Directory of Open Access Journals (Sweden)

    Débora Santos Silva Bezerra

    2010-01-01

    Full Text Available A method based on matrix solid-phase dispersion and gas chromatography-mass spectrometry to determine procymidone, malathion, bifenthrin and pirimicarb in honey is described. The best results were obtained using 1.0 g of honey, 1.0 g of silica-gel as dispersant sorbent and acetonitrile as eluting solvent. The method was validated by fortified honey samples at three concentration levels (0.2, 0.5 to 1.0 mg kg-1. Average recoveries (n=7 ranged from 54 to 84%, with relative standard deviations between 3.7 and 8.5%. Detection and quantification limits attained by the developed method ranged from 0.02 to 0.08 mg kg-1 and 0.07 to 0.25 mg kg-1 for the honey, respectively.

  4. Ozonides and epoxides from ozonization of pyrethroids

    Energy Technology Data Exchange (ETDEWEB)

    Ruzo, L.O.; Kimmel, E.C.; Casida, J.E.

    Ozonization of pyrethroids as solutions or thin films yields products proposed to be epoxides from the 2,2-dihalovinyl substituents of deltamethrin and permethrin and transitory ozonides from these compounds and more stable ozonides from the 2-methyl-1-propenyl and 2-chloro-3,3,3-trifluoropropenyl substituents of phenothrin and descyanocyhalothrin, respectively. The unstable epoxydeltamethrin from ozonization is identified by /sup 1/H nuclear magnetic resonance spectroscopy and chemical ionization-mass spectroscopy and by reversion to deltamethrin on treatment of reaction mixtures with triphenylphosphine. Degradation of the ozonides yields the corresponding caronaldehyde in each case and trifluoroacetyl chloride from the chlorotrifluoropropenyl analogues. The ozonolysis mixtures are direct acting but weak bacterial mutagens presumable due to their epoxide and ozonide components.

  5. Distribution of pyrethroid insecticides in secondary wastewater effluent.

    Science.gov (United States)

    Parry, Emily; Young, Thomas M

    2013-12-01

    Although the freely dissolved form of hydrophobic organic chemicals may best predict aquatic toxicity, differentiating between dissolved and particle-bound forms is challenging at environmentally relevant concentrations for compounds with low toxicity thresholds such as pyrethroid insecticides. The authors investigated the distribution of pyrethroids among 3 forms: freely dissolved, complexed with dissolved organic carbon, and sorbed to suspended particulate matter, during a yearlong study at a secondary wastewater treatment plant. Effluent was fractionated by laboratory centrifugation to determine whether sorption was driven by particle size. Linear distribution coefficients were estimated for pyrethroid sorption to suspended particulate matter (K(id)) and dissolved organic carbon (K(idoc)) at environmentally relevant pyrethroid concentrations. Resulting K(id) values were higher than those reported for other environmental solids, and variation between sampling events correlated well with available particle surface area. Fractionation results suggest that no more than 40% of the pyrethroid remaining in secondary effluent could be removed by extending settling periods. Less than 6% of the total pyrethroid load in wastewater effluent was present in the dissolved form across all sampling events and chemicals. © 2013 SETAC.

  6. Sublethal effects of the pyrethroid insecticide deltamethrin on oxidative stress parameters in green toad (Bufotes viridis L.).

    Science.gov (United States)

    Radovanović, Tijana B; Nasia, Mohammed; Krizmanić, Imre I; Prokić, Marko D; Gavrić, Jelena P; Despotović, Svetlana G; Gavrilović, Branka R; Borković-Mitić, Slavica S; Pavlović, Slađan Z; Saičić, Zorica S

    2017-10-01

    Pyrethroids are synthetic insecticides widely used in agriculture, public health, and veterinary medicine. Deltamethrin, a type II pyrethroid insecticide, has attracted particular attention because of its frequent use. The mechanisms of the toxicity of most pesticides (including pyrethroids) in nontarget organisms is linked to the production of free radicals, oxidative stress induction, increased lipid peroxidation, and disruption of the total antioxidant potential. The aim of the present study was to investigate the effects of acute toxicity of 3 different concentrations (8, 16, and 32 mg/kg body wt) of orally applied deltamethrin after 96 h of treatment. Some of the front-line oxidative stress parameters as well as cholinesterase (ChE) activity and cytochrome P4501A (CYP1A) expression in the liver, muscle, skin, and gastrointestinal tissue of the adult green toad Bufotes viridis were determined. Compared with the control group, the activity of catalase and glutathione reductase was increased in the liver and skin, while the concentration of sulfhydryl groups was reduced. In the liver and muscle, concentrations of thiobarbituric reactive substances were increased, as well as liver CYP1A expression. In the muscle and skin, glutathione-S-transferase activity was higher in treated toads. The oxidative stress parameters examined were affected by different deltamethrin concentrations. We conclude that the assessed parameters represent good biomarkers of pesticide-induced oxidative stress. Environ Toxicol Chem 2017;36:2814-2822. © 2017 SETAC. © 2017 SETAC.

  7. Evidence of Tolerance to Silica-Based Desiccant Dusts in a Pyrethroid-Resistant Strain of Cimex lectularius (Hemiptera: Cimicidae

    Directory of Open Access Journals (Sweden)

    David G. Lilly

    2016-12-01

    Full Text Available Insecticide resistance in bed bugs (Cimex lectularius and Cimex hemipterus has become widespread, which has necessitated the development of new IPM (Integrated Pest Management strategies and products for the eradication of infestations. Two promising options are the diatomaceous earth and silica gel-based desiccant dusts, both of which induce dehydration and eventual death upon bed bugs exposed to these products. However, the impact of underlying mechanisms that confer resistance to insecticides, such as cuticle thickening, on the performance of these dusts has yet to be determined. In the present study, two desiccant dusts, CimeXa Insecticide Dust (silica gel and Bed Bug Killer Powder (diatomaceous earth were evaluated against two strains of C. lectularius; one highly pyrethroid-resistant and one insecticide-susceptible. Label-rate doses of both products produced 100% mortality in both strains, albeit over dissimilar time-frames (3–4 days with CimeXa vs. 14 days with Bed Bug Killer. Sub-label rate exposure to CimeXa indicated that the pyrethroid-resistant strain possessed a degree of tolerance to this product, surviving 50% longer than the susceptible strain. This is the first study to suggest that mechanisms conferring resistance to pyrethroids, such as cuticular thickening, may have potential secondary impacts on non-synthetic insecticides, including desiccant dusts, which target the bed bug’s cuticle.

  8. Multiple Resistances Against Formulated Organophosphates, Pyrethroids, and Newer-Chemistry Insecticides in Populations of Helicoverpa armigera (Lepidoptera: Noctuidae) from Pakistan.

    Science.gov (United States)

    Qayyum, Mirza Abdul; Wakil, Waqas; Arif, Muhammad Jalal; Sahi, Shahbaz Talib; Saeed, Noor Abid; Russell, Derek Allan

    2015-02-01

    Field populations of Helicoverpa armigera Hübner from 15 localities across the Punjab, Pakistan, were assessed by the leaf dip method for resistance against formulated organophosphates, pyrethroids, and newer insecticide groups. Resistance levels in H. armigera have been incrementally increasing for organophosphate and pyrethroid insecticides after decades of use in Pakistan. Resistance ratios (RRs) documented for organophosphates were 24- to 116-fold for profenofos and 22- to 87-fold for chlorpyrifos. For pyrethroids, RRs were 3- to 69-fold for cypermethrin and 3- to 27-fold for deltamethrin. Resistance levels against newer chemistries were 2- to 24-fold for chlorfenapyr, 1- to 22-fold for spinosad, 1- to 20-fold for indoxacarb, 1- to 18-fold for abamectin, and 1- to 16-fold for emamectin benzoate. Resistant populations of H. armigera were mainly in the southern part of the Punjab, Pakistan. The most resistant populations were collected from Pakpattan, Multan, and Muzzafargarh. Of the nine insecticides tested, LC50 and LC90 values were lower for newer insecticide groups; resistance levels were moderate to very high against organophosphates, very low to high against pyrethroids, and very low to low against the newer-chemistry insecticides. These findings suggest that the newer-chemistry insecticides with different modes of action could be included in insecticide rotations or replace the older insecticides. Supplementing the use of synthetic insecticides with safer alternatives could help to successfully lower the farmer's reliance on insecticides and the incidence of resistance due to repeated use of insecticides against major insect pests. © 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.

  9. PYRETHROID MODULATION OF SPONTANEOUS NEURONAL EXCITABILITY AND NEUROTRANSMISSION IN HIPPOCAMPAL NEURONS IN CULTURE

    Science.gov (United States)

    Pyrethroid insecticides have potent actions on voltage-gated sodium channels, inhibiting inactivation and increasing channel open times. These are thought to underlie, at least in part, the clinical symptoms of pyrethroid intoxication. However, disruption of neuronal activity at ...

  10. Insecticidal and repellent activities of pyrethroids to the three major pyrethroid-resistant malaria vectors in western Kenya.

    Science.gov (United States)

    Kawada, Hitoshi; Ohashi, Kazunori; Dida, Gabriel O; Sonye, George; Njenga, Sammy M; Mwandawiro, Charles; Minakawa, Noboru

    2014-05-02

    The dramatic success of insecticide treated nets (ITNs) and long-lasting insecticidal nets (LLINs) in African countries has been countered by the rapid development of pyrethroid resistance in vector mosquitoes over the past decade. One advantage of the use of pyrethroids in ITNs is their excito-repellency. Use of the excito-repellency of pyrethroids might be biorational, since such repellency will not induce or delay the development of any physiological resistance. However, little is known about the relationship between the mode of insecticide resistance and excito-repellency in pyrethroid-resistant mosquitoes. Differences in the reactions of 3 major malaria vectors in western Kenya to pyrethroids were compared in laboratory tests. Adult susceptibility tests were performed using World Health Organization (WHO) test tube kits for F1 progenies of field-collected An. gambiae s.s., An. arabiensis, and An. funestus s.s., and laboratory colonies of An. gambiae s.s. and An. arabiensis. The contact repellency to pyrethroids or permethrin-impregnated LLINs (Olyset® Nets) was evaluated with a simple choice test modified by WHO test tubes and with the test modified by the WHO cone bioassay test. Field-collected An. gambiae s.s., An. arabiensis, and An. funestus s.s. showed high resistance to both permethrin and deltamethrin. The allelic frequency of the point mutation in the voltage-gated sodium channel (L1014S) in An. gambiae s.s. was 99.3-100%, while no point mutations were detected in the other 2 species. The frequency of takeoffs from the pyrethroid-treated surface and the flying times without contacting the surface increased significantly in pyrethroid-susceptible An. gambiae s.s. and An. arabiensis colonies and wild An. arabiensis and An. funestus s.s. colonies, while there was no significant increase in the frequency of takeoffs or flying time in the An. gambiae s.s. wild colony. A different repellent reaction was observed in the field-collected An. gambiae s.s. than

  11. Pyrethroid toxicity in silver catfish, Rhamdia quelen

    Directory of Open Access Journals (Sweden)

    Francisco P. Montanha

    2012-12-01

    Full Text Available This study aimed to determine both the lethal and sublethal concentrations of Cypermethrin in young Silver Catfish (Brazilian "Jundiá", Rhamdia quelen on aquatic environment during 96 hours, as well as to determine the Cypermethrin and Deltamethrin sublethal concentrations during the initial embryonic development period of Rhamdia quelen, and to verify their respective rates of fertilization, hatching and survival. Pyrethroid nowadays is a widely used insecticide, which presents a high toxicity to fish. In order to determine lethal and sublethal concentrations, 120 silver catfish were used; each one had an average weight of 59.58±4.50g and an average size of 20.33±2.34cm. Concentrations used were 0, 1.0, 1.5, 2.0, 2.5, 3.0, 5.0, 10.0, 15.0 and 20.0mg of Cypermethrin per liter of water (mg/L. Fish were exposed to the product in 30-liter fish tanks. In each fish tank there were four fishes and the product was applied three times, i.e., a total of twelve fish were exposed to the product at each application, and a total of 120 fish during the entire experiment (n=120. In order to determine the Cypermethrin and Deltamethrin sublethal concentrations during the initial embryonic development, ovulation induction was performed on female fishes using hormones, and then and egg collection was performed. The eggs were then hydrated and fertilized in Cypermethrin and Deltamethrin in different concentrations: 0.001, 0.01, 0.1, 1.0 and 10.0mg/L of Cypermethrin and 0.001, 0.01, 0.1, 0.5 and 1.0mg/L of Deltamethrin, in addition to the control group (0mg/L. After fertilization, the eggs were kept in containers with the respective pesticides of Cypermethrin and Deltamethrin until hatching, when hatching rate was verified. Then the alevins, from the hatching, were kept on their respective concentrations of Cypermethrin and Deltamethrin so that the survival rate could be analyzed regarding the tested insecticides, during both 12-hour and 24-hour periods

  12. Immune disorders induced by exposure to pyrethroid insecticides

    Directory of Open Access Journals (Sweden)

    Justyna Skolarczyk

    2017-06-01

    Full Text Available Pyrethroids are biocides, which belong to the third generation of insecticides. They are used as biocides, insecticides and medicines. These agents react selectively, because they are less harmful to birds and mammals (due to poor intestinal absorption and rapid detoxification in the body of homeothermic organisms and they are poisonous for fish and insects.The aim of the article is to present the current state of knowledge on the effects of pyrethroids on the immune system based on the latest scientific research.The mechanism of action of pyrethroids include the delaying closure of voltage- sensitive sodium and chloride channels (including GABA- dependent channels. These compounds are neurotoxic.Studies have shown that they cause numerous immune disorders contributing to lowering of immunity in humans and animals. Exposure to pyrethroids can cause inhibition of proliferation of peripheral blood leukocytes and reducing the concentration of IgG immunolgobulines. They also cause reduced macrophages and decrease in interleukin 2 (IL-2, interleukin 8 (IL-8, interleukin 12p70 (IL-12p70, and interferon γ (IFN-γ. Some of these compounds cause increase of liver weight and increase of bone marrow cellularity, and may induce apoptosis of the thymus. Pyrethroids can cause allergies and asthma. Their immunosuppressive effects can impair host resistance against infections. Exposure to these compounds can also contribute to induction of the cancer, especially in patients with impaired immune function.

  13. Immune disorders induced by exposure to pyrethroid insecticides.

    Science.gov (United States)

    Skolarczyk, Justyna; Pekar, Joanna; Nieradko-Iwanicka, Barbara

    2017-06-08

    Pyrethroids are biocides, which belong to the third generation of insecticides. They are used as biocides, insecticides and medicines. These agents react selectively, because they are less harmful to birds and mammals (due to poor intestinal absorption and rapid detoxification in the body of homeothermic organisms) and they are poisonous for fish and insects. The aim of the article is to present the current state of knowledge on the effects of pyrethroids on the immune system based on the latest scientific research. The mechanism of action of pyrethroids include the delaying closure of voltage- sensitive sodium and chloride channels (including GABA- dependent channels). These compounds are neurotoxic. Studies have shown that they cause numerous immune disorders contributing to lowering of immunity in humans and animals. Exposure to pyrethroids can cause inhibition of proliferation of peripheral blood leukocytes and reducing the concentration of IgG immunolgobulines. They also cause reduced macrophages and decrease in interleukin 2 (IL-2), interleukin 8 (IL-8), interleukin 12p70 (IL-12p70), and interferon γ (IFN-γ). Some of these compounds cause increase of liver weight and increase of bone marrow cellularity, and may induce apoptosis of the thymus. Pyrethroids can cause allergies and asthma. Their immunosuppressive effects can impair host resistance against infections. Exposure to these compounds can also contribute to induction of the cancer, especially in patients with impaired immune function.

  14. Determination of pyrethroid metabolites in human urine using liquid phase microextraction coupled in-syringe derivatization followed by gas chromatography/electron capture detection.

    Science.gov (United States)

    Lin, Chiu-Hwa; Yan, Cheing-Tong; Kumar, Ponnusamy Vinoth; Li, Hong-Ping; Jen, Jen-Fon

    2011-08-01

    Metabolites of synthetic pyrethroids such as cis-3-(2,2-dibromovinyl)-2,2-di-methylcyclo-propane-1-carboxylic acid, cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid), 3-phenoxybenzoic acid (3-PBA), and 4-fluoro-3-PBA are biomarkers for exposure to phenothrin, tetramethrin, cyfluthrin, cypermethrin, deltamethrin, and permethrin. In this study, the pyrethroid metabolites in workers' urine samples were monitored for the first time with a novel sample pretreatment process combining hollow fiber liquid phase microextraction (HF-LPME) and in-syringe derivatization (ISD) followed by gas chromatography-electron capture detector (GC-ECD) analysis. A micro-syringe pre-filled with derivatizing agents and syringe needle connected to an extracting solvent impregnated hollow fiber segment was used as the LPME probe. Pyrethroid metabolites were extracted and enriched simultaneously from urine samples by HF-LPME sampling and acid hydrolysis at 70 °C for 10 min. After sampling, the ISD was performed by mixing the extracting solution and derivatizing agents through plunger movements, followed by GC-ECD analysis. Parameters influencing the HF-LPME efficiency and ISD were investigated and optimized. Under optimum conditions, the method provided enrichment factors of 69.8-154.6, repeatability from 5.0 to 12% (n = 5), and good linearity (R(2) = 0.9980-0.9998) for interested analytes spiked in urine samples. The method detection limits ranged from 1.6 to 17 ng/mL. A comparison was performed between the proposed method and conventional methods. The proposed method was applied to analyze pyrethroid metabolites in the urine samples collected from workers of pesticide formulation plants. The results suggested that the proposed HF-LPME coupled ISD method was a rapid, simple, efficient, and eco-friendly technique in the biomonitoring of metabolites of pyrethroids in workers' urine.

  15. [EFFECT OF PYRETHROIDS ON TAIGA TICKS (IXODES PERSULCATUS IXODIDAE)].

    Science.gov (United States)

    Germant, O M; Shashina, N I

    2016-01-01

    Nonspecific prevention of infections, the agents of which are transmitted by Ixodes ticks, is aimed at stopping the suction of the ticks to humans and is substantially based one the use of acaricides. The most interesting group of compounds to be used to individually protect humans is pyrethroids that cause different nerve conduction disturbances in the ticks, which result in their paralysis and death more significantly rapidly than the compounds from other chemical groups. The effect of 8 pyrethroids was investigated when the taiga ticks were in contact with the tissue treated with the compounds. The relationship of the chemical structure of pyrethroids with their acaricidal activity was analyzed from motor activity values and knockdown time. The test pyreithroids, in order of decreasing acaricidal activity, are imiprothrin cyphenothrin, cyfluthrin, alpha-cyperamethrin, zeta-cyperimethrin fenothrin, flumethrin.

  16. Pyrethroid residue dynamics in insects depends on the circadian clock.

    Science.gov (United States)

    Maliszewska, Justyna; Piechowicz, Bartosz; Maciąga, Gabriela; Zaręba, Lech; Marcinkowska, Sonia

    2018-02-27

    Many factors may affect pesticide effectiveness against pests. One of the factors that should be considered is circadian rhythmicity. In this study, we evaluated daily variations in pyrethroid susceptibility in the house cricket, Acheta domesticus L. Crickets were exposed to a standard dose of ß-cyfluthrin at different times of a day, and pesticide residue levels were evaluated using gas chromatography. Results demonstrate that the time of pyrethroid disappearance is correlated with the circadian clock, with the highest decomposition rate at night. Furthermore, crickets also showed the highest resistance to the insecticide at night, expressed as a high survival rate. Moreover, ß-cyfluthrin induced significant changes in thermal preferences of intoxicated crickets. This is the first report showing that pyrethroid residue levels in the crickets' body depend on its circadian clock.

  17. Voltage-gated sodium channels as targets for pyrethroid insecticides.

    Science.gov (United States)

    Field, Linda M; Emyr Davies, T G; O'Reilly, Andrias O; Williamson, Martin S; Wallace, B A

    2017-10-01

    The pyrethroid insecticides are a very successful group of compounds that have been used extensively for the control of arthropod pests of agricultural crops and vectors of animal and human disease. Unfortunately, this has led to the development of resistance to the compounds in many species. The mode of action of pyrethroids is known to be via interactions with the voltage-gated sodium channel. Understanding how binding to the channel is affected by amino acid substitutions that give rise to resistance has helped to elucidate the mode of action of the compounds and the molecular basis of their selectivity for insects vs mammals and between insects and other arthropods. Modelling of the channel/pyrethroid interactions, coupled with the ability to express mutant channels in oocytes and study function, has led to knowledge of both how the channels function and potentially how to design novel insecticides with greater species selectivity.

  18. POTENTIATION OF COPAÍBA OIL-RESIN WITH SYNTHETIC INSECTICIDES TO CONTROL OF FALL ARMYWORM

    OpenAIRE

    ALMEIDA, WALDIANE ARAÚJO DE; SILVA, IGOR HONORATO LEDUÍNO DA; SANTOS, ANA CLÁUDIA VIEIRA DOS; BARROS JÚNIOR, AURÉLIO PAES; SOUSA, ADALBERTO HIPÓLITO DE

    2017-01-01

    ABSTRACT The control of Spodoptera frugiperda (J. E. SMITH) (Lepidoptera: Noctuidae) has been carried out mainly with pyrethroids and organophosphates insecticides. The continuous and indiscriminate use of synthetic insecticides, for decades, has led to the selection of resistant populations and has caused concerns for human health and the environment. An alternative is the use of botanical insecticides, including through the mixtures with synthetic insecticides. This study aimed to investiga...

  19. Passive dosing of pyrethroid insecticides to Daphnia magna: Expressing excess toxicity by chemical activity

    DEFF Research Database (Denmark)

    Nørgaard Schmidt, Stine; Gan, Jay; Kretschmann, A. C.

    2015-01-01

    ) Effective chemical activities resulting in 50% immobilisation (Ea50) will be estimated from pyrethroid EC50 values via the correlation of sub-cooled liquid solubility (S L, [mmol/L], representing a=1) and octanol to water partitioning ratios (Kow), (3) The excess toxicity observed for pyrethroids...... activity do pyrethroids exert their toxicity, and how similar are the effective chemical activities (Ea50) for different pyrethroids? (3) How much more toxic are pyrethroids relative to baseline toxicity? Toxicity experiments were conducted using passive dosing: Polydimethyl siloxane (PDMS) silicone...

  20. Molecular determinants on the insect sodium channel for the specific action of type II pyrethroid insecticides

    Science.gov (United States)

    Du, Yuzhe; Nomura, Yoshiko; Luo, Ningguang; Liu, Zhiqi; Lee, Jung-Eun; Khambay, Bhupinder; Dong, Ke

    2011-01-01

    Pyrethroid insecticides are classified as type I or type II based on their distinct symptomology and effects on sodium channel gating. Structurally, type II pyrethroids possess an α-cyano group at the phenylbenzyl alcohol position, which is lacking in type I pyrethroids. Both type I and type II pyrethroids inhibit deactivation consequently prolonging the opening of sodium channels. However, type II pyrethroids inhibit the deactivation of sodium channels to a greater extent than type I pyrethroids inducing much slower decaying of tail currents upon repolarization. The molecular basis of type II-specific action, however, is not known. Here we report the identification of a residue G1111 and two positively charged lysines immediately downstream of G1111 in the intracellular linker connecting domains II and III of the cockroach sodium channel that are specifically involved in the action of type II pyrethroids, but not in the action of type I pyrethroids. Deletion of G1111, a consequence of alternative splicing, reduced the sodium channel sensitivity to type II pyrethroids, but had no effect on channel sensitivity to type I pyrethroids. Interestingly, charge neutralization or charge reversal of two positively charged lysines (Ks) downstream of G1111 had a similar effect. These results provide the molecular insight into the type II-specific interaction of pyrethroids with the sodium channel at the molecular level. PMID:19022275

  1. Insecticide pyrethroids in liver of striped dolphin from the Mediterranean Sea.

    Science.gov (United States)

    Aznar-Alemany, Òscar; Giménez, Joan; de Stephanis, Renaud; Eljarrat, Ethel; Barceló, Damià

    2017-06-01

    Pyrethroid pesticides were analysed in liver of striped dolphin (Stenella coeruleoalba) from the Alboran Sea (south of Spain, Mediterranean Sea). The occurrence and bioaccumulation of pyrethroid insecticides in marine mammal tissues from the northern hemisphere had never been determined before. Pyrethroids were detected in 87% of the specimens with a mean total concentration of 300 ng g -1 lw ± 932 (range 2.7-5200 ng g -1 lw). Permethrin and tetramethrin were the main contributors to the pyrethroid profiles, with enantiospecific accumulation for the first and isomer specific accumulation for the latter. Bioaccumulation of pyrethroids was unlike that of persistent organic pollutants (POPs), as pyrethroid concentrations were not correlated to the maturity stage of the specimens. Concentrations slightly increased from calves to juveniles, whereas juveniles presented similar concentrations to adults. Metabolization of pyrethroids after achieving sexual maturity might account for this pattern. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Methocarbamol CRI for symptomatic treatment of pyrethroid intoxication: a report of three cases.

    Science.gov (United States)

    Draper, William E; Bolfer, Luiz; Cottam, Emily; McMichael, Maureen; Schubert, Thomas

    2013-01-01

    Pyrethroids are popular for use in companion animals due to their relatively low mammalian toxicity and efficacy against arthropods. Nonetheless, pyrethroid intoxication has been reported in cats and dogs, and cats appear to be more susceptible due to difficulty in biotransformation and excretion of pyrethroids. Pyrethroid intoxications are generally due to either the improper use or accidental ingestion of approved products. Methocarbamol, given as intermittent injections, is a common first-line treatment choice for the tremors associated with pyrethroid intoxication. Two cats and one dog were treated with a methocarbamol continuous rate infusion (CRI) for pyrethroid intoxication. Clinical signs of toxicity resolved within a few hr in all three cases, with no adverse drug effects. A methocarbamol CRI can be considered in animals presenting with pyrethroid intoxication.

  3. Measurement of plasma protein and lipoprotein binding of pyrethroids.

    Science.gov (United States)

    Sethi, Pankaj K; Muralidhara, S; Bruckner, James V; White, Catherine A

    2014-01-01

    A simple, reliable procedure was developed to measure binding of pyrethroid insecticides to total proteins and lipoproteins of rat and human plasma. The extent of binding of (14)C-labeled deltamethrin (DLM), cis-permethrin (CIS) and trans-permethrin (TRANS) was quantified by a 3-step organic solvent extraction technique. Rat and human plasma samples, containing NaF to inhibit esterases, were spiked with a range of concentrations of each radiolabeled pyrethroid. Protein binding reached equilibrium within ~1h of incubation at 37°C. The samples were extracted in turn with: isooctane to collect the unbound fraction; 2-octanol to extract the lipoprotein-bound fraction; and acetonitrile to obtain the protein-bound fraction. Absolute recoveries of DLM, CIS and TRANS ranged from 86 to 95%. Adherence of these very lipophilic chemicals to glass and plastic was minimized by using silanized glass vials and LoBind® plastic pipettes. The method's ability to distinguish lipoprotein from protein binding was confirmed by experiments with diazepam and cyclosporine, drugs that bind selectively to albumin and lipoproteins, respectively. This procedure was effectively utilized for studies of the species-dependence of plasma protein and lipoprotein binding of three pyrethroids for inclusion in physiologically-based pharmacokinetic models of pyrethroids for use in health risk assessments of the insecticides in children and adults. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Identification and evaluation of pyrethroid insecticide mixtures in urban sediments.

    Science.gov (United States)

    Trimble, Andrew J; Weston, Donald P; Belden, Jason B; Lydy, Michael J

    2009-08-01

    Organochlorine, organophosphorous, and pyrethroid insecticides frequently have been detected together as mixtures in stream sediments. To simplify mixture analyses, additive toxic responses usually are assumed but rarely are confirmed, especially for compounds with similar modes of action. The first objective of the present study was to screen a database of 24 different pesticides and 94 urban-stream sediment samples collected throughout central and northern California (USA) to identify compounds and partial mixtures that dominated sample toxicity to Hyalella azteca. Pyrethroids and chlorpyrifos were the most toxicologically relevant compounds in terms of detection frequency, contribution to overall sample toxicity, and co-occurrence in the most common mixture patterns. Organochlorine insecticides were the least toxicologically relevant compounds, with only a small percentage of samples exceeding predefined screening values. The second objective was to confirm that mixtures of type I and type II pyrethroids display additive responses. Ten-day sediment toxicity tests of binary pesticide mixtures were conducted using H. azteca as the test organism. Observed dose-response curves were compared to those predicted from concentration-addition and independent-action models. Model deviation ratios (MDRs) were calculated at the median effect level to quantify the magnitudes of deviation between observed and predicted curves. Whereas the concentration-addition model adequately predicted toxicity for all the pyrethroid mixtures (MDRs within a factor of two), dose-response values deviated from additivity enough to warrant further investigation.

  5. Copper clean-up procedure for ultrasonic extraction and analysis of pyrethroid and phenylpyrazole pesticides in sediments by gas chromatography-electron capture detection

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jun; Lin Youjian; Lu Jian; Wilson, Chris, E-mail: pcwilson@ufl.edu

    2011-08-15

    A rapid ultrasonic extraction method coupled with a heated-copper clean-up procedure for removing interfering constituents was developed for analyzing pyrethroid and phenylpyrazole pesticides in sediments. Incubation of the 60 mL extract with 12 g copper granules at 60 {sup o}C for 2 h was determined to be the optimal conditions for removing the interfering constituents. Eleven pyrethroid and phenylpyrazole pesticides were spiked into sediment samples to determine the effectiveness of the ultrasonic extraction method. The average recoveries of pyrethroids and phenylpyrazoles in sediment at 4 {sup o}C storage on day 0, 1, 7, 14, and 21 ranged from 98.6 to 120.0%, 79.2 to 116.0%, 85.0 to 119.7%, 93.6 to 118.7%, and 92.1 to 118.2%, respectively, with all percent relative standard deviations less than 10% (most < 6%). This illustrated the stability of pyrethroids and phenylpyrazoles in sediment during sediment aging at 4 {sup o}C. Recoveries of the pesticides ranged from 98.6% to 120.0% for lowest fortification level (2-16 {mu}g kg{sup -1}), from 97.8% to 117.9% for middle fortification level (10-80 {mu}g kg{sup -1}), and from 94.3% to 118.1% for highest fortification level (20-160 {mu}g kg{sup -1}). Relative standard deviations of pesticide recoveries were usually less than 7%. Method detection limits of target pesticides ranged from 0.22 {mu}g kg{sup -1} to 3.72 {mu}g kg{sup -1}. Furthermore, field sediment samples collected from four residential lakes during a three-month monitoring period were analyzed to evaluate the effectiveness of this method. Bifenthrin was detected in all of sediment samples (highest concentration 260.33 {+-} 41.71 {mu}g kg{sup -1}, lowest concentration 5.68 {+-} 0.38 {mu}g kg{sup -1}), and fipronil sulfone was detected at least once in sediment samples collected from three sites with concentrations ranging from 1.73 {+-} 0.53 to 7.53 {+-} 0.01 {mu}g kg{sup -1}. - Highlights: {yields} A rapid extraction and copper-based clean-up method was

  6. Synthetic Cannabinoids

    Directory of Open Access Journals (Sweden)

    Aslihan Okan Ibiloglu

    2017-09-01

    Full Text Available Synthetic cannabinoids which is a subgroup of cannabinoids are commonly used for recreational drug use throughout the whole world. Although both marijuana and synthetic cannabinoids stimulate the same receptors, cannabinoid receptor 1 (CB1 and cannabinoid receptor 2 (CB2, studies have shown that synthetic cannabinoids are much more potent than marijuana. The longer use of synthetic cannabinoids can cause severe physical and psychological symptoms that might even result in death, similar to many known illicit drugs. Main treatment options mostly involve symptom management and supportive care. The aim of this article is to discuss clinical and pharmacological properties of the increasingly used synthetic cannabinoids. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2017; 9(3.000: 317-328

  7. From the Cover: Vulnerability of C6 Astrocytoma Cells After Single-Compound and Joint Exposure to Type I and Type II Pyrethroid Insecticides.

    Science.gov (United States)

    Romero, Delfina M; Berardino, Bruno G; Wolansky, Marcelo J; Kotler, Mónica L

    2017-01-01

    A primary mode-of-action of all pyrethroid insecticides (PYRs) is the disruption of the voltage-gated sodium channel electrophysiology in neurons of target pests and nontarget species. The neurological actions of PYRs on non-neuronal cells of the nervous system remain poorly investigated. In the present work, we used C6 astrocytoma cells to study PYR actions (0.1-50 μM) under the hypothesis that glial cells may be targeted by and vulnerable to PYRs. To this end, we characterized the effects of bifenthrin (BF), tefluthrin (TF), α-cypermethrin (α-CYP), and deltamethrin (DM) on the integrity of nuclear, mitochondrial, and lysosomal compartments. In general, 24- to 48-h exposures produced concentration-related impairment of cell viability. In single-compound, 24-h exposure experiments, effective concentration (EC) 15 s 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT assay) were computed as follows (in μM): BF, 16.1; TF, 37.3; α-CYP, 7.8; DM, 5.0. We found concentration-related damage in several C6-cell subcellular compartments (mitochondria, nuclei, and lysosomes) at ≥ 10 -1 μM levels. Last, we examined a mixture of all PYRs (ie, Σ individual EC 15 ) using MTT assays and subcellular analyses. Our findings indicate that C6 cells are responsive to nM levels of PYRs, suggesting that astroglial susceptibility may contribute to the low-dose neurological effects caused by these insecticides. This research further suggests that C6 cells may provide relevant information as a screening platform for pesticide mixtures targeting nervous system cells by expected and unexpected toxicogenic pathways potentially contributing to clinical neurotoxicity. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  8. Synthetic oils

    Science.gov (United States)

    Hatton, R. E.

    1973-01-01

    Synthetic lubricants are discussed by chemical class and their general strengths and weaknesses in terms of lubrication properties are analyzed. Comparative ratings are given for 14 chemical classes and are used as a guide for lubricant selection. The effects of chemical structure on the properties of the lubricant are described with special emphasis on thermal stability. The diversity of synthetic lubricants which is provided by the wide range of properties permits many applications, some of which are reported.

  9. Molecular evidence for dual pyrethroid-receptor sites on a mosquito sodium channel

    Science.gov (United States)

    Nomura, Yoshiko; Satar, Gul; Hu, Zhaonong; Nauen, Ralf; He, Sheng Yang; Zhorov, Boris S.; Dong, Ke

    2013-01-01

    Pyrethroid insecticides are widely used as one of the most effective control measures in the global fight against agricultural arthropod pests and mosquito-borne diseases, including malaria and dengue. They exert toxic effects by altering the function of voltage-gated sodium channels, which are essential for proper electrical signaling in the nervous system. A major threat to the sustained use of pyrethroids for vector control is the emergence of mosquito resistance to pyrethroids worldwide. Here, we report the successful expression of a sodium channel, AaNav1–1, from Aedes aegypti in Xenopus oocytes, and the functional examination of nine sodium channel mutations that are associated with pyrethroid resistance in various Ae. aegypti and Anopheles gambiae populations around the world. Our analysis shows that five of the nine mutations reduce AaNav1–1 sensitivity to pyrethroids. Computer modeling and further mutational analysis revealed a surprising finding: Although two of the five confirmed mutations map to a previously proposed pyrethroid-receptor site in the house fly sodium channel, the other three mutations are mapped to a second receptor site. Discovery of this second putative receptor site provides a dual-receptor paradigm that could explain much of the molecular mechanisms of pyrethroid action and resistance as well as the high selectivity of pyrethroids on insect vs. mammalian sodium channels. Results from this study could impact future prediction and monitoring of pyrethroid resistance in mosquitoes and other arthropod pests and disease vectors. PMID:23821746

  10. Increasing use of pyrethroids in Canadian households: should we be concerned?

    Science.gov (United States)

    van Balen, Erna C; Wolansky, Marcelo J; Kosatsky, Tom

    2012-11-07

    Pyrethroids are a class of plant-derived insecticides and their man-made analogues that are increasingly applied in Canada as first choice for pest control in many agricultural and residential settings. Their popularity is partly due to their alleged safety compared to the older organochlorine and organophosphate insecticides. Application of pyrethroids is expanding because of recent increases in the level of pest infestations--such as bed bugs--and the decreased susceptibility of target species to many pest control products. Pyrethroid residues have been documented in homes, child care centres and food. While pyrethroids are considered of low health risk for humans, their increased use is of concern. Our current understanding of the adverse effects of pyrethroids derives mainly from studies of short-term effects in laboratory animals, case reports of self- and accidental poisonings, and high-dose occupational exposures, for which the levels and formulations of pyrethroid products differ from those relevant for long-term exposure in the general population. The available data suggest that the reproductive and nervous systems, endocrine signalling pathways, and early childhood development may be targets for adverse effects in the case of repeated exposure to pyrethroid formulations. Given uncertainty about the existence of long-term health effects of exposure to pyrethroids, particularly under realistic scenarios, we should be cautious when promoting pyrethroid products as safe methods for pest control.

  11. Pyrethroid-Induced Reproductive Toxico-Pathology in Non-Target Species

    Directory of Open Access Journals (Sweden)

    Latif Ahmad§, Ahrar Khan* and Muhammad Zargham Khan

    2012-01-01

    Full Text Available Pesticides used against agricultural pests and ecto-parasite infestation in animals may also induce injurious effects in humans, pets and farm animals. The pyrethroid pesticides are rapidly replacing other insecticides due to relatively lower toxicity for mammals. However, they have now become an environmental issue due to excessive use in agriculture, livestock production, leather industry and shampoos etc. In addition to various clinical, hemato-biochemical, immunosuppressive and neuro-toxicological effects of pyrethroids, more danger has been suspected with respect to reproductive toxicity. The fetal resorption and early fetal mortality rate were found to be significantly increased in female animals allowed mating with males exposed to pyrethroids. The testicular and epididymal sperm counts and serum testosterone concentrations in pyrethroid treated animals were decreased. Moreover, abnormal spermatozoa, degenerated spermatozoa, arrested spermatogenesis and connective tissue proliferation in testes, and tailless spermatozoa in epididymis were reported with pyrethroid exposure. A decrease in pregnancy rate, number of implantation sites and total number of recovered fetuses have also been reported in female animals receiving pyrethroid treatment during gestation and allowed mating with untreated male rabbits. The progeny of pyrethroid exposed parents also showed toxic effects. Disruption of certain steroidogenic enzymes and nuclear receptors in has been reported in pyrethroid exposed animals. This review concludes that pyrethroid exposure is responsible for endocrine disruption and decreases fertility in both sexes of various non-target species and produces fetal mortality, which may be prevented by vitamin E supplementation due to its anti-oxidant potential.

  12. Assessment of the inhibitory effects of pyrethroids against human carboxylesterases.

    Science.gov (United States)

    Lei, Wei; Wang, Dan-Dan; Dou, Tong-Yi; Hou, Jie; Feng, Liang; Yin, Heng; Luo, Qun; Sun, Jie; Ge, Guang-Bo; Yang, Ling

    2017-04-15

    Pyrethroids are broad-spectrum insecticides that widely used in many countries, while humans may be exposed to these toxins by drinking or eating pesticide-contaminated foods. This study aimed to investigate the inhibitory effects of six commonly used pyrethroids against two major human carboxylesterases (CES) including CES1 and CES2. Three optical probe substrates for CES1 (DME, BMBT and DMCB) and a fluorescent probe substrate for CES2 (DDAB) were used to characterize the inhibitory effects of these pyrethroids. The results demonstrated that most of the tested pyrethroids showed moderate to weak inhibitory effects against both CES1 and CES2, but deltamethrin displayed strong inhibition towards CES1. The IC 50 values of deltamethrin against CES1-mediated BMBT, DME, and DMCB hydrolysis were determined as 1.58μM, 2.39μM, and 3.3μM, respectively. Moreover, deltamethrin was cell membrane permeable and capable of inhibition endogenous CES1 in living cells. Further investigation revealed that deltamethrin inhibited CES1-mediated BMBT hydrolysis via competitive manner but noncompetitively inhibited DME or DMCB hydrolysis. The inhibition behaviors of deltamethrin against CES1 were also studied by molecular docking simulation. The results demonstrated that CES1 had at least two different ligand-binding sites, one was the DME site and another was the BMBT site which was identical to the binding site of deltamethrin. In summary, deltamethrin was a strong reversible inhibitor against CES1 and it could tightly bind on CES1 at the same ligand-binding site as BMBT. These findings are helpful for the deep understanding of the interactions between xenobiotics and CES1. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Pyrethroid insecticides and their environmental degradates in repeated duplicate-diet solid food samples of 50 adults

    Science.gov (United States)

    Previous research has reported concurrent levels of pyrethroid insecticides and their environmental degradates in foods. These data raise concerns about using these same pyrethroid degradates found in the diet as urinary biomarkers of exposures in humans. The primary objective wa...

  14. Effects of an Environmentally-relevant Mixture of Pyrethroid Insecticides on Spontaneous Activity in Primary Cortical Networks on Microelectrode Arrays

    Science.gov (United States)

    Pyrethroid insecticides exert their insecticidal and toxicological effects primarily by disrupting voltage-gated sodium channel (VGSC) function, resulting in altered neuronal excitability. Numerous studies of individual pyrethroids have characterized effects on mammalian VGSC fun...

  15. Synthetic environments

    Science.gov (United States)

    Lukes, George E.; Cain, Joel M.

    1996-02-01

    The Advanced Distributed Simulation (ADS) Synthetic Environments Program seeks to create robust virtual worlds from operational terrain and environmental data sources of sufficient fidelity and currency to interact with the real world. While some applications can be met by direct exploitation of standard digital terrain data, more demanding applications -- particularly those support operations 'close to the ground' -- are well-served by emerging capabilities for 'value-adding' by the user working with controlled imagery. For users to rigorously refine and exploit controlled imagery within functionally different workstations they must have a shared framework to allow interoperability within and between these environments in terms of passing image and object coordinates and other information using a variety of validated sensor models. The Synthetic Environments Program is now being expanded to address rapid construction of virtual worlds with research initiatives in digital mapping, softcopy workstations, and cartographic image understanding. The Synthetic Environments Program is also participating in a joint initiative for a sensor model applications programer's interface (API) to ensure that a common controlled imagery exploitation framework is available to all researchers, developers and users. This presentation provides an introduction to ADS and the associated requirements for synthetic environments to support synthetic theaters of war. It provides a technical rationale for exploring applications of image understanding technology to automated cartography in support of ADS and related programs benefitting from automated analysis of mapping, earth resources and reconnaissance imagery. And it provides an overview and status of the joint initiative for a sensor model API.

  16. Cotton pest management practices and the selection of pyrethroid resistance in Anopheles gambiae population in Northern Benin

    OpenAIRE

    Yadouleton, A.; Martin, T.; Padonou, G.; Chandre, Fabrice; Asidi, A.; Djogbénou, Luc; Dabiré, R.; Aikpon, R.; Boko, M.; Glitho, I.; Akogbeto, M.

    2011-01-01

    Abstract Background Pyrethroid insecticides, carbamate and organophosphate are the classes of insecticides commonly used in agriculture for crop protection in Benin. Pyrethroids remain the only class of insecticides recommended by the WHO for impregnation of bed nets. Unfortunately, the high level of pyrethroid resistance in Anopheles gambiae s.l., threatens to undermine the success of pyrethroid treated nets. This study focuses on the investigation of agricultural practices in cotton growing...

  17. Increase of sodium current after pyrethroid insecticides in mouse neuroblastoma cells

    NARCIS (Netherlands)

    Ruigt, G.S.F.; Neyt, H.C.; Zalm, J.M. van der; Bercken, J. van der

    1987-01-01

    The effects of 4 different pyrethroid insecticides on sodium channel gating in internally perfused, cultured mouse neuroblastoma cells (N1E-115) were studied using the suction pipette, voltage clamp technique. Pyrethroids increased the amplitude of the sodium current, sometimes by more than 200%.

  18. Additivity of Pyrethroid Actions on Sodium Influx in Cortical Neuronsin vitro

    Science.gov (United States)

    Background: Pyrethroid insecticides bind to voltage-gated sodium channels (VGSCs) and modify their gating kinetics, thereby disrupting neuronal function. While previous work has tested the additivity of pyrethroids in vivo, the additivity of these compounds at the major target si...

  19. Interactions of pyrethroid insecticides with GABA sub A and peripheral-type benzodiazepine receptors

    Energy Technology Data Exchange (ETDEWEB)

    Devaud, L.L.

    1988-01-01

    Pyrethroid insecticides are potent proconvulsants in the rat. All pyrethroids evincing proconvulsant activity elicited a similar 25-30% maximal reduction of seizure threshold. The Type II pyrethroids were the most potent proconvulsants with 1R{alpha}S, cis cypermethrin having an ED{sub 50} value of 6.3 nmol/kg. The proconvulsant activity of both Type I and Type II pyrenthroids was blocked by pretreatment with PK 11195, the peripheral-type benzodiazepine receptor (PTBR) antagonist. In contrast, phenytoin did not antagonize the proconvulsant activity of either deltamethrin or permethrin. Pyrethroids displaced the specific binding of ({sup 3}H)Ro5-4864 to rat brain membranes with a significant correlation between the log EC{sub 50} values for their activities as proconvulsants and the log IC{sub 50} values for their inhibition of ({sup 3}H)Ro5-4864 binding. Both Ro5-4864 and pyrethroid insecticides were found to influence specific ({sup 35}S)TBPS binding in a GABA-dependent manner. PK 11195 and the Type II pyrethroid, deltamethrin antagonized the Ro5-4864-induced modulation of ({sup 35}S)TBPS binding. Pyrethroid insecticides, Ro5-4864 and veratridine influenced GABA-gated {sup 36}Chloride influx. Moreover, the Type II pyrethroids elicited an increase in {sup 36}chloride influx in the absence of GABA-stimulation. Both of these actions were antagonized by PK 11195 and tetrodotoxin.

  20. Collection of Pyrethroids in Water and Sediment Matrices: Development and Validation of a Standard Operating Procedure

    Science.gov (United States)

    Hladik, Michelle; Orlando, James L.; Kuivila, Kathryn

    2009-01-01

    Loss of pyrethroid insecticides onto surfaces during sample collection can confound the interpretation of analytical and toxicity test results. Sample collection devices, container materials, and water matrix composition have a significant influence on the association of pyrethroids to container walls, which can be as high as 50 percent. Any sample collection method involving transfer through multiple containers or pieces of equipment increases the potential for pyrethroid loss. This loose 'surface-association' with container walls can be reversed through agitation. When sampling water matrices with pumps or autosamplers, no pyrethroids were lost as long as the water was moving continuously through the system. When collecting water matrices in containers, the material with the least amount of pyrethroid sorption is as follows: glass less than (pyrethroids were easier to re-suspend from the glass container walls. Since the amount of surface-association is proportional to the ratio of volume-to-contact-area of the sample, taking larger-volume field samples (greater than 3 liters) reduced pyrethroid losses to less than 10 percent. The amount of surface-association cannot be predicted easily because of the dependence on water matrix composition; samples with higher dissolved organic carbon or suspended-sediment concentrations were observed to have lower percent loss. Sediment samples were not affected by glass-container sorption (the only containers tested). Standardized sample-collection protocols are critical to yield accurate pyrethroid concentrations for assessment of potential effects, and have been summarized in an accompanying standard operating procedure.

  1. ACTIONS OF PYRETHROID INSECTICIDES ON THE SPONTANEOUS RELEASE OF GLUTAMATE FROM CULTURED HIPPOCAMPAL NEURONS.

    Science.gov (United States)

    Pyrethroid insecticides increase the excitability of the central and peripheral nervous systems. Modulation of voltage-gated sodium channels is likely to play a primary role in this effect, but recent studies have suggested that pyrethroid effects on other ion channels may contri...

  2. Pyrethroid effects on freshwater invertebrates: A meta-analysis of pulse exposures

    DEFF Research Database (Denmark)

    Rasmussen, Jes Jessen; Wiberg-Larsen, Peter; Kristensen, Esben Astrup

    2013-01-01

    Pyrethroids are widely used insecticides that may seriously harm aquatic organisms. Being strongly hydrophobic, pyrethroids in solution occur only in short pulses but may be retained in sediments for longer periods. Consequently, most studies consider the chronic exposure of sediment dwelling org...

  3. Evidence for Dose-Additive Effects of Pyrethroids on Motor Activity in Rats

    Science.gov (United States)

    BACKGROUND: Pyrethroids are neurotoxic insecticides used in a variety of indoor and outdoor applications. Previous research characterized the acute dose-effect functions for 11 pyrethroids administered orally in corn oil (1 mL/kg) based on assessment of motor activity. OBJECTIVES...

  4. Optimization and validation of molecular diagnosis of pyrethroid pesticide resistance in Brazilian populations of horn flies

    Science.gov (United States)

    Pyrethroid resistance is a serious problem to cattle producers in Brazil. There are specific resistance-associated mutations, known as kdr and super-kdr, in the region of DNA that codes for the target of pyrethroids, the sodium channel protein. The presence of these mutations in the sodium channel c...

  5. Synthetic Rutile

    International Nuclear Information System (INIS)

    Burastero, J.

    1975-01-01

    This work is about the laboratory scale investigation of the conditions in the rutile synthetic production from one me nita in Aguas Dulces reservoir. The iron mineral is chlorinated and volatilized selectively leaving a residue enriched in titanium dioxide which can be used as a substitute of rutile mineral

  6. Pyrethroid insecticides and radioligand displacement from the GABA receptor chloride ionophore complex

    Energy Technology Data Exchange (ETDEWEB)

    Crofton, K.M.; Reiter, L.W.; Mailman, R.B.

    1987-01-01

    Radioligand binding displacement studies were conducted to determine the effects of Type I and II pyrethroids on /sup 3/H-flunitrazepam (FLU), /sup 3/H-muscimol (MUS), and (/sup 35/S-t-butylbicyclophosphorothionate (TBPS) binding. Competition experiments with /sup 3/H-FLU and /sup 3/H-MUS indicate a lack of competition for binding by the pyrethroids. Type I pyrethroids failed to compete for the binding of (/sup 35/S-TBPS at concentrations as high as 50 pM. Type II pyrethroids inhibited (/sup 35/S-TBPS binding to rat brain synaptosomes with Ki values ranging from 5-10 pM. The data presented suggest that the interaction of Type II pyrethroids with the GABA receptor-ionophore complex is restricted to a site near the TBPS/picrotoxinin binding site.

  7. A new detection method for a newly revealed mechanism of pyrethroid resistance development in Varroa destructor.

    Science.gov (United States)

    Strachecka, Aneta; Borsuk, Grzegorz; Olszewski, Krzysztof; Paleolog, Jerzy

    2015-11-01

    The Varroa destructor mite has recently displayed an ever increasing resistance to new drugs, contributing to CCD proliferation. This work was aimed at determining new viable methods for identifying the pyrethroid resistance of V. destructor and DNA methylation in resistant and sensitive mites. DNA was extracted from Varroa mites. Nucleotide changes in the DNA of pyrethroid-resistant, pyrethroid-sensitive, and control mites were identified with polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) in the case of five mitochondrial gene fragments. More bands were observed in the drug-resistant mites than in the other two groups. Sequencing confirmed these observations. Decreased global DNA methylation levels were observed in the pyrethroid-resistant mites. There exists a previously undescribed mechanism of pyrethroid resistance development in Varroa mites. The PCR-SSCP methods can be considered and further developed as useful tools for detecting V. destructor resistance.

  8. Influence on Transfer of selected synthetic pyrethroids from treated Formica® to Foods

    Science.gov (United States)

    Children’s unstructured eating habits and activities may lead to excess dietary exposures not traditionally taken into consideration. Influence of these activities on transfer of pesticides from treated Formica® to foods was studied. The objective was to perform simulation expe...

  9. Mechanism of resistance to synthetic pyrethroids in buffalo flies in south-east Queensland

    Science.gov (United States)

    Buffalo fly (Haematobia irritans exigua) and horn fly (Haematobia irritans irritans) cause irritation and production loss in much of the cattle producing area of the world. In Australia losses from buffalo fly were recently estimated at A$78m per year. Control is largely performed by using organoph...

  10. The aquatic ecotoxicology of the synthetic pyrethroids: from laboratory to landscape

    NARCIS (Netherlands)

    Maund, S.J.

    2009-01-01

    Synthetische pyrethroïden (SPs) hebben voor een doorbraak in de bestrijding van insectplagen gezorgd door hun breed-spectrum werkzaamheid bij lage doseringen, terwijl ze een relatief lage toxiciteit hebben voor zoogdieren. Bezorgdheid is gerezen omtrent de hoge toxiciteit van SPs voor aquatische

  11. Collembola and macroarthropod community responses to carbamate, organophosphate and synthetic pyrethroid insecticides: direct and indirect effects

    NARCIS (Netherlands)

    Frampton, G.K.; Brink, van den P.J.

    2007-01-01

    Non-target effects on terrestrial arthropod communities of the broad-spectrum insecticides chlorpyrifos and cypermethrin and the selective insecticide pirimicarb were investigated in winter wheat fields in summer. Effects of chlorpyrifos on arthropod abundance and taxonomic richness were

  12. Pyrethroid Activity-Based Probes for Profiling Cytochrome P450 Activities Associated with Insecticide Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Hanafy M.; O' Neill, Paul M.; Hong, David; Finn, Robert; Henderson, Colin; Wright, Aaron T.; Cravatt, Benjamin; Hemingway, Janet; Paine, Mark J.

    2014-01-18

    Pyrethroid insecticides are used to control a diverse spectrum of diseases spread by arthropods. We have developed a suite of pyrethroid mimetic activity based probes (PyABPs) to selectively label and identify P450s associated with pyrethroid metabolism. The probes were screened against pyrethroid metabolizing and non-metabolizing mosquito P450s, as well as rodent microsomes to measure labeling specificity, plus CPR and b5 knockout mouse livers to validate P450 activation and establish the role for b5 in probe activation. Using a deltamethrin mimetic PyABP we were able to profile active enzymes in rat liver microsomes and identify pyrethroid metabolizing enzymes in the target tissue. The most reactive enzyme was a P450, CYP2C11, which is known to metabolize deltamethrin. Furthermore, several other pyrethroid metabolizers were identified (CYPs 2C6, 3A4, 2C13 and 2D1) along with related detoxification enzymes, notably UDP-g’s 2B1 - 5, suggesting a network of associated pyrethroid metabolizing enzymes, or ‘pyrethrome’. Considering the central role that P450s play in metabolizing insecticides, we anticipate that PyABPs will aid the identification and profiling of P450s associated with insecticide pharmacology in a wide range of species, improving understanding of P450-insecticide interactions and aiding the development of new tools for disease control.

  13. Identification and characterisation of Aedes aegypti aldehyde dehydrogenases involved in pyrethroid metabolism.

    Directory of Open Access Journals (Sweden)

    Nongkran Lumjuan

    Full Text Available Pyrethroid insecticides, especially permethrin and deltamethrin, have been used extensively worldwide for mosquito control. However, insecticide resistance can spread through a population very rapidly under strong selection pressure from insecticide use. The upregulation of aldehyde dehydrogenase (ALDH has been reported upon pyrethroid treatment. In Aedes aegypti, the increase in ALDH activity against the hydrolytic product of pyrethroid has been observed in DDT/permethrin-resistant strains. The objective of this study was to identify the role of individual ALDHs involved in pyrethroid metabolism.Three ALDHs were identified; two of these, ALDH9948 and ALDH14080, were upregulated in terms of both mRNA and protein levels in a DDT/pyrethroid-resistant strain of Ae. aegypti. Recombinant ALDH9948 and ALDH14080 exhibited oxidase activities to catalyse the oxidation of a permethrin intermediate, phenoxybenzyl aldehyde (PBald, to phenoxybenzoic acid (PBacid.ALDHs have been identified in association with permethrin resistance in Ae. aegypti. Characterisation of recombinant ALDHs confirmed the role of this protein in pyrethroid metabolism. Understanding the biochemical and molecular mechanisms of pyrethroid resistance provides information for improving vector control strategies.

  14. Pyrethroid insecticide exposure and reproductive hormone levels in healthy Japanese male subjects

    DEFF Research Database (Denmark)

    Yoshinaga, J; Imai, K; Shiraishi, H

    2014-01-01

    The associations between serum levels of reproductive hormones (follicle-stimulating hormone, luteinizing hormone, testosterone, sex hormone-binding globulin, inhibin B and calculated free testosterone) and urinary metabolite concentration of pyrethroid insecticides [3-phenoxybenzoic acid (3-PBA...... composition of pyrethroid insecticides to which the subjects were exposed; 3-PBA is a common metabolite of a number of pyrethroids and thus lacks specificity to compounds that may have different potentials of reproductive toxicity. Another reason might be related to the fact that our subjects were university...

  15. Rotational Symmetry of Two Pyrethroid Receptor Sites in the Mosquito Sodium Channel

    Science.gov (United States)

    Du, Yuzhe; Nomura, Yoshiko; Zhorov, Boris S.

    2015-01-01

    Voltage-gated sodium channels are the primary target of pyrethroid insecticides. Although it is well known that specific mutations in insect sodium channels confer knockdown resistance (kdr) to pyrethroids, the atomic mechanisms of pyrethroid-sodium channel interactions are not clearly understood. Previously, computer modeling and mutational analysis predicted two pyrethroid receptors, pyrethroid receptor site 1 (PyR1) (initial) and pyrethroid receptor site 2 (PyR2), located in the domain interfaces II/III and I/II, respectively. The models differ in ligand orientation and the number of transmembrane helices involved. In this study, we elaborated a revised PyR1 model of the mosquito sodium channel. Computational docking in the Kv1.2-based open channel model yielded a complex in which a pyrethroid (deltamethrin) binds between the linker helix IIL45 and transmembrane helices IIS5, IIS6, and IIIS6 with its dibromoethenyl and diphenylether moieties oriented in the intra- and extracellular directions, respectively. The PyR2 and revised PyR1 models explained recently discovered kdr mutations and predicted new deltamethrin-channel contacts. Further model-driven mutagenesis identified seven new pyrethroid-sensing residues, three in the revised PyR1 and four in PyR2. Our data support the following conclusions: 1) each pyrethroid receptor is formed by a linker-helix L45 and three transmembrane helices (S5 and two S6s); 2) IIS6 contains four residues that contribute to PyR1 and another four to PyR2; 3) seven pairs of pyrethroid-sensing residues are located in symmetric positions within PyR1 and PyR2; and 4) pyrethroids bind to PyR1 and PyR2 in similar orientations, penetrating deeply into the respective domain interfaces. Our study elaborates the dual pyrethroid-receptor sites concept and provides a structural background for rational development of new insecticides. PMID:25972447

  16. Synthetic Cannabinoids.

    Science.gov (United States)

    Mills, Brooke; Yepes, Andres; Nugent, Kenneth

    2015-07-01

    Synthetic cannabinoids (SCBs), also known under the brand names of "Spice," "K2," "herbal incense," "Cloud 9," "Mojo" and many others, are becoming a large public health concern due not only to their increasing use but also to their unpredictable toxicity and abuse potential. There are many types of SCBs, each having a unique binding affinity for cannabinoid receptors. Although both Δ-tetrahydrocannabinol (THC) and SCBs stimulate the same receptors, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), studies have shown that SCBs are associated with higher rates of toxicity and hospital admissions than is natural cannabis. This is likely due to SCBs being direct agonists of the cannabinoid receptors, whereas THC is a partial agonist. Furthermore, the different chemical structures of SCBs found in Spice or K2 may interact in unpredictable ways to elicit previously unknown, and the commercial products may have unknown contaminants. The largest group of users is men in their 20s who participate in polydrug use. The most common reported toxicities with SCB use based on studies using Texas Poison Control records are tachycardia, agitation and irritability, drowsiness, hallucinations, delusions, hypertension, nausea, confusion, dizziness, vertigo and chest pain. Acute kidney injury has also been strongly associated with SCB use. Treatment mostly involves symptom management and supportive care. More research is needed to identify which contaminants are typically found in synthetic marijuana and to understand the interactions between different SBCs to better predict adverse health outcomes.

  17. Incremental impact upon malaria transmission of supplementing pyrethroid-impregnated long-lasting insecticidal nets with indoor residual spraying using pyrethroids or the organophosphate, pirimiphos methyl.

    Science.gov (United States)

    Hamainza, Busiku; Sikaala, Chadwick H; Moonga, Hawela B; Chanda, Javan; Chinula, Dingani; Mwenda, Mulenga; Kamuliwo, Mulakwa; Bennett, Adam; Seyoum, Aklilu; Killeen, Gerry F

    2016-02-18

    Long-lasting, insecticidal nets (LLINs) and indoor residual spraying (IRS) are the most widely accepted and applied malaria vector control methods. However, evidence that incremental impact is achieved when they are combined remains limited and inconsistent. Fourteen population clusters of approximately 1000 residents each in Zambia's Luangwa and Nyimba districts, which had high pre-existing usage rates (81.7 %) of pyrethroid-impregnated LLINs were quasi-randomly assigned to receive IRS with either of two pyrethroids, namely deltamethrin [Wetable granules (WG)] and lambdacyhalothrin [capsule suspension (CS)], with an emulsifiable concentrate (EC) or CS formulation of the organophosphate pirimiphos methyl (PM), or with no supplementary vector control measure. Diagnostic positivity of patients tested for malaria by community health workers in these clusters was surveyed longitudinally over pre- and post-treatment periods spanning 29 months, over which the treatments were allocated and re-allocated in advance of three sequential rainy seasons. Supplementation of LLINs with PM CS offered the greatest initial level of protection against malaria in the first 3 months of application (incremental protective efficacy (IPE) [95 % confidence interval (CI)] = 0.63 [CI 0.57, 0.69], P pyrethroid formulation provided protection beyond 3 months after spraying, but the protection provided by both PM formulations persisted undiminished for longer periods: 6 months for CS and 12 months for EC. The CS formulation of PM provided greater protection than the combined pyrethroid IRS formulations throughout its effective life IPE [95 % CI] = 0.79 [0.75, 0.83] over 6 months. The EC formulation of PM provided incremental protection for the first 3 months (IPE [95 % CI] = 0.23 [0.15, 0.31]) that was approximately equivalent to the two pyrethroid formulations (lambdacyhalothrin, IPE [95 % CI] = 0.31 [0.10, 0.47] and deltamethrin, IPE [95 % CI] = 0.19 [-0.01, 0.35]) but the additional

  18. Synthetic Botany.

    Science.gov (United States)

    Boehm, Christian R; Pollak, Bernardo; Purswani, Nuri; Patron, Nicola; Haseloff, Jim

    2017-07-05

    Plants are attractive platforms for synthetic biology and metabolic engineering. Plants' modular and plastic body plans, capacity for photosynthesis, extensive secondary metabolism, and agronomic systems for large-scale production make them ideal targets for genetic reprogramming. However, efforts in this area have been constrained by slow growth, long life cycles, the requirement for specialized facilities, a paucity of efficient tools for genetic manipulation, and the complexity of multicellularity. There is a need for better experimental and theoretical frameworks to understand the way genetic networks, cellular populations, and tissue-wide physical processes interact at different scales. We highlight new approaches to the DNA-based manipulation of plants and the use of advanced quantitative imaging techniques in simple plant models such as Marchantia polymorpha. These offer the prospects of improved understanding of plant dynamics and new approaches to rational engineering of plant traits. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  19. Synthetic Brainbows

    KAUST Repository

    Wan, Y.

    2013-06-01

    Brainbow is a genetic engineering technique that randomly colorizes cells. Biological samples processed with this technique and imaged with confocal microscopy have distinctive colors for individual cells. Complex cellular structures can then be easily visualized. However, the complexity of the Brainbow technique limits its applications. In practice, most confocal microscopy scans use different florescence staining with typically at most three distinct cellular structures. These structures are often packed and obscure each other in rendered images making analysis difficult. In this paper, we leverage a process known as GPU framebuffer feedback loops to synthesize Brainbow-like images. In addition, we incorporate ID shuffing and Monte-Carlo sampling into our technique, so that it can be applied to single-channel confocal microscopy data. The synthesized Brainbow images are presented to domain experts with positive feedback. A user survey demonstrates that our synthetic Brainbow technique improves visualizations of volume data with complex structures for biologists.

  20. Pyrethroid resistance in an Anopheles funestus population from Uganda.

    Directory of Open Access Journals (Sweden)

    John C Morgan

    2010-07-01

    Full Text Available The susceptibility status of Anopheles funestus to insecticides remains largely unknown in most parts of Africa because of the difficulty in rearing field-caught mosquitoes of this malaria vector. Here we report the susceptibility status of the An. funestus population from Tororo district in Uganda and a preliminary characterisation of the putative resistance mechanisms involved.A new forced egg laying technique used in this study significantly increased the numbers of field-caught females laying eggs and generated more than 4000 F1 adults. WHO bioassays indicated that An. funestus in Tororo is resistant to pyrethroids (62% mortality after 1 h exposure to 0.75% permethrin and 28% mortality to 0.05% deltamethrin. Suspected DDT resistance was also observed with 82% mortality. However this population is fully susceptible to bendiocarb (carbamate, malathion (organophosphate and dieldrin with 100% mortality observed after exposure to each of these insecticides. Sequencing of a fragment of the sodium channel gene containing the 1014 codon conferring pyrethroid/DDT resistance in An. gambiae did not detect the L1014F kdr mutation but a correlation between haplotypes and resistance phenotype was observed indicating that mutations in other exons may be conferring the knockdown resistance in this species. Biochemical assays suggest that resistance in this population is mediated by metabolic resistance with elevated level of GSTs, P450s and pNPA compared to a susceptible strain of Anopheles gambiae. RT-PCR further confirmed the involvement of P450s with a 12-fold over-expression of CYP6P9b in the Tororo population compared to the fully susceptible laboratory colony FANG.This study represents the first report of pyrethroid/DDT resistance in An. funestus from East Africa. With resistance already reported in southern and West Africa, this indicates that resistance in An. funestus may be more widespread than previously assumed and therefore this should be taken

  1. Changes in host orientation behavior of female mosquitoes treated with a sublethal pyrethroid exposure

    Science.gov (United States)

    Adult mosquito control consists of barrier treatments and areal spraying often using pyrethroids, however not all host seeking insects contacting insecticides are killed. Sublethal exposure to neurotoxic compounds can negatively affect sensory organs reducing their efficiency for locating hosts. Fe...

  2. Detection of pyrethroid pesticides and their environmental degradation products in duplicate diet samples

    Science.gov (United States)

    The abstract is for an oral presentation at the Asilomar Conference on Mass Spectrometry: Mass Spectrometry in Environmental Chemistry, Toxicology, and Health. It describes analytical method development and sample results for determination of pyrethroid pesticides and environme...

  3. Developmentally-regulated sodium channel subunits are differentially sensitive to α–cyano containing pyrethroids

    Science.gov (United States)

    Juvenile rats have been reported to be more sensitive to the acute neurotoxic effects of the pyrethroid deltamethrin than adults. While toxicokinetic differences between juveniles and adults are documented, toxicodynamic differences have not been examined. Voltage-gated sodium ch...

  4. Characterization of pyrethroid resistance and susceptibility to coumaphos in Mexican Boophilus microplus (Acari: Ixodidae).

    Science.gov (United States)

    Miller, R J; Davey, R B; George, J E

    1999-09-01

    Two patterns of pyrethroid resistance were characterized from Boophilus microplus (Canestrini) collected in Mexico. One was characteristic of a kdr mutation and the other involved esterase and cytochrome P450 enzyme systems. Very high resistance to permethrin, cypermethrin, and flumethrin, not synergized by TPP and PBO and high resistance to DDT, characterized the kdr-like pattern found in the Corrales and San Felipe strains. Esterase and cytochrome P450-dependent resistance was found in the Coatzacoalcos strain. It was characterized by resistance to permethrin, cypermethrin, and flumethrin, synergized by TPP and PBO, but no resistance to DDT. The Coatzacoalcos strain also showed 3.6-fold resistance to the organophosphate coumaphos. This factor appeared to be independent of pyrethroid resistance. Pyrethroid resistance patterns found in Mexico were similar to those found earlier in Australia. The significance of pyrethroid and coumaphos resistance to the U.S. cattle fever tick quarantine is discussed.

  5. EFFECTS OF DIETARY EXPOSURE TO THE PYRETHROID PESTICIDE ESFENVALERATE ON MEDAKA (ORYZIAS LATIPES). (R826940)

    Science.gov (United States)

    AbstractThe pyrethroid insecticide esfenvalerate is widely used on orchard crops throughout California. In the aquatic environment, this compound is likely to accumulate in sediments, food particles and benthic organisms due to its lipophilicity and environmental pers...

  6. Pesticide loadings of select organophosphate and pyrethroid pesticides in urban public housing.

    Science.gov (United States)

    We investigated the magnitude and distribution of pyrethroid and organophosphate pesticide loadings within public housing dwellings in Boston, Massachusetts and compared the results using various sampling methods. We collected dust matrices from living room and kitchen in 42 apar...

  7. Application of spinosad increases the susceptibility of insecticide-resistant Alphitobius diaperinus (Coleoptera: Tenebrionidae) to pyrethroids.

    Science.gov (United States)

    Lambkin, Trevor A; Furlong, Michael J

    2014-08-01

    The effect of spinosad exposure on the susceptibility of pyrethroid- and organophosphate-resistant populations of lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), to insecticides was investigated in broiler house farm and laboratory studies. A field pyrethroid- and organophosphate-resistant population showed a 3.6-fold increase in susceptibility to gamma-cyhalothrin following spinosad treatment. Overall, cyfluthrin- and fenitrothion-resistant field populations were more susceptible to these insecticides following spinosad treatments, but populations that were not resistant showed no change in susceptibility following spinosad treatment. In a related study, three broiler farm beetle populations with very similar levels of cyfluthrin and gamma-cyhalothrin resistance and similar susceptibilities to spinosad were used to investigate temporal effects of spinosad field treatments on the susceptibility to pyrethroids. Farm insecticide regimes applied at the start of each flock differed: the control broiler house received no insecticide applications, another house was systematically treated with cyfluthrin at the start of each study flock, and the third house was systematically treated with spinosad at the start of five flocks. Afterwards, treatments reverted to cyfluthrin on all farms. At the end of flocks, beetles were tested with cyfluthrin, gamma-cyhalothrin, and spinosad. The control and cyfluthrin house beetles did not change susceptibility to pyrethroids over the period of the study. In the spinosad house, spinosad had no effect on spinosad susceptibility but dramatically increased cyfluthrin and gamma-cyhalothrin susceptibilities. These new susceptibilities were maintained while spinosad applications continued, but pyrethroid susceptibility declined once spinosad applications ceased. This study provides evidence of a synergistic interaction between spinosad and pyrethroids in pyrethroid-resistant beetles. This evidence has significant

  8. Evidence for Dose-Additive Effects of Pyrethroids on Motor Activity in Rats

    Science.gov (United States)

    Wolansky, Marcelo J.; Gennings, Chris; DeVito, Michael J.; Crofton, Kevin M.

    2009-01-01

    Background Pyrethroids are neurotoxic insecticides used in a variety of indoor and outdoor applications. Previous research characterized the acute dose–effect functions for 11 pyrethroids administered orally in corn oil (1 mL/kg) based on assessment of motor activity. Objectives We used a mixture of these 11 pyrethroids and the same testing paradigm used in single-compound assays to test the hypothesis that cumulative neurotoxic effects of pyrethroid mixtures can be predicted using the default dose–addition theory. Methods Mixing ratios of the 11 pyrethroids in the tested mixture were based on the ED30 (effective dose that produces a 30% decrease in response) of the individual chemical (i.e., the mixture comprised equipotent amounts of each pyrethroid). The highest concentration of each individual chemical in the mixture was less than the threshold for inducing behavioral effects. Adult male rats received acute oral exposure to corn oil (control) or dilutions of the stock mixture solution. The mixture of 11 pyrethroids was administered either simultaneously (2 hr before testing) or after a sequence based on times of peak effect for the individual chemicals (4, 2, and 1 hr before testing). A threshold additivity model was fit to the single-chemical data to predict the theoretical dose–effect relationship for the mixture under the assumption of dose additivity. Results When subthreshold doses of individual chemicals were combined in the mixtures, we found significant dose-related decreases in motor activity. Further, we found no departure from the predicted dose-additive curve regardless of the mixture dosing protocol used. Conclusion In this article we present the first in vivo evidence on pyrethroid cumulative effects supporting the default assumption of dose addition. PMID:20019907

  9. Eficácia biológica de bifentrina aplicado em milho armazenado sob diferentes temperaturas Biological efficacy of applied bifenthrin in stored corn under different temperatures

    Directory of Open Access Journals (Sweden)

    Marco A. G. Pimentel

    2005-06-01

    Full Text Available Considerando-se as altas temperaturas nos graneleiros junto à esteira transportadora de grãos objetivou-se, neste trabalho, avaliar a influência da temperatura no momento da pulverização, sobre a eficácia biológica do bifentrina. Para isso, pulverizou-se o inseticida sobre grãos de milho dentro de uma câmara climática nas temperaturas de 25, 30, 35, 40, 45 e 50 ºC, com umidade relativa em torno de 55%. Após a pulverização e a cada 15 dias, até completar 90 dias, foram feitas as análises da eficácia biológica utilizando-se os insetos Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae, Rhyzopertha dominica (Fabricius (Coleoptera: Bostrichidae e Tribolium castaneum (Herbst (Coleoptera: Tenebrionidae. Observou-se tendência decrescente da eficácia biológica do bifentrina com o aumento da temperatura do ar ambiente, no momento da pulverização e com o maior tempo de armazenamento dos grãos de milho, resultando em menor mortalidade dos insetos-praga.Considering the high temperatures in the granary ships alongwith the transporting mat, the objective of this paper was to evaluate the influence of the temperature at the moment of spraying on the biological effectiveness of the bifenthrin. For the purpose the insecticide was sprayed on maize grains inside a climatic chamber maintained at the temperatures of 25, 30, 35, 40, 45 and 50 ºC with relative humidity around 55%. After the spraying and every fifteen days up to 90 days, analyses of the biological effectiveness were made by using insects of the Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae, Rhyzopertha dominica (Fabricius (Coleoptera: Bostrichidae and Tribolium castaneum (Herbst (Coleoptera: Tenebrionidae. A decreasing tendency of the biological effectiveness of the bifenthrin was observed with the increase of the air temperature at the moment of spraying and with the increased time of maize storage, resulting in a smaller mortality of the insect-pest.

  10. Pyrethroid resistance in Aedes aegypti and Aedes albopictus: Important mosquito vectors of human diseases.

    Science.gov (United States)

    Smith, Letícia B; Kasai, Shinji; Scott, Jeffrey G

    2016-10-01

    Aedes aegypti and A. albopictus mosquitoes are vectors of important human disease viruses, including dengue, yellow fever, chikungunya and Zika. Pyrethroid insecticides are widely used to control adult Aedes mosquitoes, especially during disease outbreaks. Herein, we review the status of pyrethroid resistance in A. aegypti and A. albopictus, mechanisms of resistance, fitness costs associated with resistance alleles and provide suggestions for future research. The widespread use of pyrethroids has given rise to many populations with varying levels of resistance worldwide, albeit with substantial geographical variation. In adult A. aegypti and A. albopictus, resistance levels are generally lower in Asia, Africa and the USA, and higher in Latin America, although there are exceptions. Susceptible populations still exist in several areas of the world, particularly in Asia and South America. Resistance to pyrethroids in larvae is also geographically widespread. The two major mechanisms of pyrethroid resistance are increased detoxification due to P450-monooxygenases, and mutations in the voltage sensitive sodium channel (Vssc) gene. Several P450s have been putatively associated with insecticide resistance, but the specific P450s involved are not fully elucidated. Pyrethroid resistance can be due to single mutations or combinations of mutations in Vssc. The presence of multiple Vssc mutations can lead to extremely high levels of resistance. Suggestions for future research needs are presented. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Molecular analysis of pyrethroid resistance conferred by target insensitivity and increased metabolic detoxification in Plutella xylostella.

    Science.gov (United States)

    Sonoda, Shoji

    2010-05-01

    The pyrethroid resistance of the diamondback moth Plutella xylostella (L.) is conferred by increased gene expression of cytochrome P450 to detoxify the insecticide and/or through gene mutation of the sodium channel, which makes the individual insensitive to pyrethroids. However, no information is available about the correlation between the increased metabolic detoxification and the target insensitivity in pyrethroid resistance. Frequencies of pyrethroid-resistant alleles (L1014F, T929I and M918I) and two resistance-related mutations (A1101T and P1879S) at the sodium channel and expression levels of the cytochrome P450 gene CYP6BG1 were examined individually using laboratory and field strains of P. xylostella. Real-time quantitative PCR analysis using the laboratory strains revealed that levels of larval expression of the resistant strain, homozygous for the pyrethroid-resistant alleles other than the M918I, are significantly higher than those of the susceptible strain. In the field strains, the expression levels in insects having the same resistant alleles as those of the resistant strains varied greatly among individuals. The expression levels were not significantly higher than those in the heterozygotes. Significant correlation between the target insensitivity and the increased metabolic detoxification in pyrethroid resistance of P. xylostella was observed in the laboratory but not in the field.

  12. Phytoremediation of organochlorine and pyrethroid pesticides by aquatic macrophytes and algae in freshwater systems.

    Science.gov (United States)

    Riaz, Ghazala; Tabinda, Amtul Bari; Iqbal, Shakir; Yasar, Abdullah; Abbas, Mateen; Khan, Abdul Muqeet; Mahfooz, Yusra; Baqar, Mujtaba

    2017-10-03

    Extensive use of Pesticides in agriculture and its surface runoff in river water is a major environmental concern. The present study evaluated the phytoremediation potential of Eichornia crassipes, Pistia strateotes and algae (Chaetomorpha sutoria, Sirogonium sticticum and Zygnema sp.) for organochlorine and pyrethroid pesticides. Water and plant samples were extracted by liquid phase and solid phase extraction respectively and analyzed by high-performance liquid chromatography. Eleven treatments (T1-T11) with and without plants were used for phytoremediation of organochlorine and pyrethroid pesticides. During the experiment, P. strateotes, E. crassipes and algae (C. sutoria, S. sticticum and Zygnema sp.) showed the highest removal efficiency with 62 (71% root, 29% shoot), 60 (67% root, 33% shoot), and 58% respectively for organochlorine and 76 (76% root, 24% shoot), 68 (69% root, 31% shoot), and 70% respectively for pyrethroids for the respective aquatic plants. Dissipation rate constant of treatments with plants (T2, T3, T5, T6, T8, and T9) was significantly higher (p plants (T10 and T11, control) for both organochlorine and pyrethroid. The bioconcentration factor of pyrethroid treatments (T3, T6, and T9) was significantly higher (p < 0.05) as compared to that of organochlorine treatments (T2, T5 and T8). The removal efficiency of E. crassipes, P. strateotes and algae (C. sutoria, S. sticticum and Zygnema sp.) for pyrethroids was significantly higher (p < 0.01) as compared to that of organochlorine.

  13. Seasonal sensitivity of Gammarus pulex towards the pyrethroid cypermethrin.

    Science.gov (United States)

    Dalhoff, Kristoffer; Gottardi, Michele; Rinnan, Åsmund; Rasmussen, Jes Jessen; Cedergreen, Nina

    2018-06-01

    The aquatic toxicity of insecticides like the pyrethroids have been discussed intensively over the recent years especially in relation to risk assessment and how seasonality may or may not affect the sensitivity of non-target organisms. To address this issue, the crustacean Gammarus pulex was collected once a month for 16 months and acclimated to 10 °C for four days before being exposed to a 90 min pulse of cypermethrin. In vitro cytochrome P450 activity, total lipid content, total protein content, and dry weight were measured in male and female gammarids from each sampling date and used along with the water temperature as variables for sensitivity prediction by Partial Least Squares (PLS) regression models. The 24 h EC 50 -values varied more than 30 fold across the sampling period from 0.21 ± 0.05 μg L -1 (April 2015) to 6.60 ± 3.46 μg L -1 (October 2015), indicating seasonal variances in the acute sensitivity of G. pulex towards cypermethrin. After 168 h of recovery this difference in EC 50 -values was reduced to seven-fold. In both male and female gammarids seasonal patterns were observed in the total lipid content and in vitro CYP P450 activity, which peaked in spring and fall, respectively. The current study shows the importance of reporting time of organism collection and experimental execution for risk assessment of pyrethroids as season is important for the acute sensitivity of G. pulex. We suggest prolonged acclimation times of sampled macroinvertebrates to constant laboratory conditions in order to even out possible seasonal differences in sensitivity. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Pyrethroid pesticide-induced alterations in dopamine transporter function

    International Nuclear Information System (INIS)

    Elwan, Mohamed A.; Richardson, Jason R.; Guillot, Thomas S.; Caudle, W. Michael; Miller, Gary W.

    2006-01-01

    Parkinson's disease (PD) is a progressive neurodegenerative disease affecting the nigrostriatal dopaminergic pathway. Several epidemiological studies have demonstrated an association between pesticide exposure and the incidence of PD. Studies from our laboratory and others have demonstrated that certain pesticides increase levels of the dopamine transporter (DAT), an integral component of dopaminergic neurotransmission and a gateway for dopaminergic neurotoxins. Here, we report that repeated exposure (3 injections over 2 weeks) of mice to two commonly used pyrethroid pesticides, deltamethrin (3 mg/kg) and permethrin (0.8 mg/kg), increases DAT-mediated dopamine uptake by 31 and 28%, respectively. Using cells stably expressing DAT, we determined that exposure (10 min) to deltamethrin and permethrin (1 nM-100 μM) had no effect on DAT-mediated dopamine uptake. Extending exposures to both pesticides for 30 min (10 μM) or 24 h (1, 5, and 10 μM) resulted in significant decrease in dopamine uptake. This reduction was not the result of competitive inhibition, loss of DAT protein, or cytotoxicity. However, there was an increase in DNA fragmentation, an index of apoptosis, in cells exhibiting reduced uptake at 30 min and 24 h. These data suggest that up-regulation of DAT by in vivo pyrethroid exposure is an indirect effect and that longer-term exposure of cells results in apoptosis. Since DAT can greatly affect the vulnerability of dopamine neurons to neurotoxicants, up-regulation of DAT by deltamethrin and permethrin may increase the susceptibility of dopamine neurons to toxic insult, which may provide insight into the association between pesticide exposure and PD

  15. Predictive 3D modelling of the interactions of pyrethroids with the voltage-gated sodium channels of ticks and mites.

    Science.gov (United States)

    O'Reilly, Andrias O; Williamson, Martin S; González-Cabrera, Joel; Turberg, Andreas; Field, Linda M; Wallace, B A; Davies, T G Emyr

    2014-03-01

    The pyrethroid insecticides are a very successful group of compounds that target invertebrate voltage-gated sodium channels and are widely used in the control of insects, ticks and mites. It is well established that some pyrethroids are good insecticides whereas others are more effective as acaricides. This species specificity is advantageous for controlling particular pest(s) in the presence of another non-target invertebrate, for example controlling the Varroa mite in honeybee colonies. We applied in silico techniques to compare the voltage-gated sodium channels of insects versus ticks and mites and their interactions with a range of pyrethroids and DDT analogues. We identified a single amino acid difference within the pyrethroid binding pocket of ticks/mites that may have significant impact on the effectiveness of pyrethroids as acaricides. Other individual amino acid differences within the binding pocket in distinct tick and mite species may provide a basis for future acaricidal selectivity. Three-dimensional modelling of the pyrethroid/DDT receptor site has led to a new hypothesis to explain the preferential binding of acaricidal pyrethroids to the sodium channels of ticks/mites. This is important for understanding pyrethroid selectivity and the potential effects of mutations that can give rise to resistance to pyrethroids in commercially-important pest species. © 2013 Society of Chemical Industry.

  16. Iodine labelled pyrethroids, their chemical preparation and their application to radioimmunoassays. Pyrethrinoides marques a l'iode, leur procede de preparation et leur application aux dosages radioimmunologiques

    Energy Technology Data Exchange (ETDEWEB)

    Demoute, J.P.; Touer, G.; Mouren, M.

    1987-07-31

    This invention deals with iodine 125 or iodine 131 labelled pyrethroids, their chemical preparations and their application to radioimmunoassay for the determination of pyrethroids (deltamethrin) in human, or animal body fluids.

  17. Control of Pyrethroid-Resistant Chagas Disease Vectors with Entomopathogenic Fungi

    Science.gov (United States)

    Pedrini, Nicolás; Mijailovsky, Sergio J.; Girotti, Juan R.; Stariolo, Raúl; Cardozo, Rubén M.; Gentile, Alberto; Juárez, M. Patricia

    2009-01-01

    Background Triatoma infestans-mediated transmission of Tripanosoma cruzi, the causative agent of Chagas disease, remains as a major health issue in southern South America. Key factors of T. infestans prevalence in specific areas of the geographic Gran Chaco region—which extends through northern Argentina, Bolivia, and Paraguay—are both recurrent reinfestations after insecticide spraying and emerging pyrethroid-resistance over the past ten years. Among alternative control tools, the pathogenicity of entomopathogenic fungi against triatomines is already known; furthermore, these fungi have the ability to fully degrade hydrocarbons from T. infestans cuticle and to utilize them as fuel and for incorporation into cellular components. Methodology and Findings Here we provide evidence of resistance-related cuticle differences; capillary gas chromatography coupled to mass spectrometry analyses revealed that pyrethroid-resistant bugs have significantly larger amounts of surface hydrocarbons, peaking 56.2±6.4% higher than susceptible specimens. Also, a thicker cuticle was detected by scanning electron microscopy (32.1±5.9 µm and 17.8±5.4 µm for pyrethroid-resistant and pyrethroid-susceptible, respectively). In laboratory bioassays, we showed that the virulence of the entomopathogenic fungi Beauveria bassiana against T. infestans was significantly enhanced after fungal adaptation to grow on a medium containing insect-like hydrocarbons as the carbon source, regardless of bug susceptibility to pyrethroids. We designed an attraction-infection trap based on manipulating T. infestans behavior in order to facilitate close contact with B. bassiana. Field assays performed in rural village houses infested with pyrethroid-resistant insects showed 52.4% bug mortality. Using available mathematical models, we predicted that further fungal applications could eventually halt infection transmission. Conclusions This low cost, low tech, ecologically friendly methodology could help in

  18. Urinary metabolites of organophosphate and pyrethroid pesticides and behavioral problems in Canadian children.

    Science.gov (United States)

    Oulhote, Youssef; Bouchard, Maryse F

    2013-01-01

    Exposure to organophosphate pesticides has been associated with neurobehavioral deficits in children, although data on low levels of exposure experienced by the general population are sparse. Pyrethroids are insecticides rapidly gaining popularity, and epidemiological evidence on their potential effects is lacking. We examined the association between exposure to organophosphate and pyrethroid pesticides, indicated by urinary metabolites, and parentally reported behavioral problems in children. We used data on children 6-11 years of age from the Canadian Health Measures Survey (2007-2009). We used logistic regressions to estimate odds ratios (ORs) for high scores on the Strengths and Difficulties Questionnaire (SDQ), which may indicate behavioral problems, in association with concentrations of pyrethroid and organophosphate metabolites in the urine of 779 children, adjusting for covariates (sex, age, race/ethnicity, income, parental education, blood lead levels, maternal smoking during pregnancy, and others). At least one urinary metabolite for organophosphates was detected in 91% of children, and for pyrethroids in 97% of children. Organophosphate metabolites were not significantly associated with high SDQ scores. The pyrethroid metabolite cis-DCCA [3-(2,2-dichlorovinyl)-2,2-dimethylycyclopropane carboxylic acid] was significantly associated with high scores for total difficulties on the SDQ (OR for a 10-fold increase = 2.0; 95% CI: 1.1, 3.6), and there was a nonsignificant association with trans-DCCA (OR = 1.6; 95% CI: 0.9, 3.0). In contrast with previous studies, we did not observe an association between exposure to organophosphate pesticides and behavioral scores in children. However, some pyrethroid urinary metabolites were associated with a high level of parent-reported behavioral problems. Longitudinal studies should be conducted on the potential risks of pyrethroids.

  19. Cuticle thickening associated with pyrethroid resistance in the major malaria vector Anopheles funestus

    Directory of Open Access Journals (Sweden)

    Coetzee M

    2010-08-01

    Full Text Available Abstract Background Malaria in South Africa is primarily transmitted by Anopheles funestus Giles. Resistance to pyrethroid insecticides in An. funestus in northern Kwazulu/Natal, South Africa, and in neighbouring areas of southern Mozambique enabled populations of this species to increase their ranges into areas where pyrethroids were being exclusively used for malaria control. Pyrethroid resistance in southern African An. funestus is primarily conferred by monooxygenase enzyme metabolism. However, selection for this resistance mechanism is likely to have occurred in conjunction with other factors that improve production of the resistance phenotype. A strong candidate is cuticle thickening. This is because thicker cuticles lead to slower rates of insecticide absorption, which is likely to increase the efficiency of metabolic detoxification. Results Measures of mean cuticle thickness in laboratory samples of female An. funestus were obtained using scanning electron microscopy (SEM. These females were drawn from a laboratory colony carrying the pyrethroid resistance phenotype at a stable rate, but not fixed. Prior to cuticle thickness measurements, these samples were characterised as either more or less tolerant to permethrin exposure in one experiment, and either permethrin resistant or susceptible in another experiment. There was a significant and positive correlation between mean cuticle thickness and time to knock down during exposure to permethrin. Mean cuticle thickness was significantly greater in those samples characterised either as more tolerant or resistant to permethrin exposure compared to those characterised as either less tolerant or permethrin susceptible. Further, insecticide susceptible female An. funestus have thicker cuticles than their male counterparts. Conclusion Pyrethroid tolerant or resistant An. funestus females are likely to have thicker cuticles than less tolerant or susceptible females, and females generally have

  20. Gene structure and expression of a pyrethroid-metabolizing esterase, CzEst9, from a pyrethroid resistant Mexican population of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

    Science.gov (United States)

    Guerrero, Felix D; Nene, Vishvanath M

    2008-07-01

    A population of Rhipicephalus (Boophilus) microplus (Canestrini) (Acari: Ixodidae), designated Coatzacoalcos, sampled from a ranch near Veracruz, Mexico, was found to possess a high level of resistance to pyrethroid-based acaricides. Bioassay and biochemical and molecular analysis had previously shown that resistance in this population could primarily be attributed to expression of a highly active metabolic esterase designated CzEST9. We cloned and sequenced the entire CzEST9 coding region, including introns and > 1.0 kb upstream from the transcription start site, and we compared the upstream region sequence between individual resistant and susceptible ticks from several populations with different pyrethroid resistance characteristics. In the 1.0-kb upstream region sequence, four variant nucleotides were found, and a TGA trinucleotide occurred as either four, five, or nine tandem repeats. However, none of these promoter region sequence differences could be clearly associated with a pyrethroid-resistant phenotype; thus, we concluded that differences in gene promoter sequence were not responsible for the pyrethroid resistance mechanism in the Cz strain. CzEST9 was expressed in recombinant Escherichia coli and Pichia pastoris systems and esterase activity was obtained in recombinant CzEST9 from the P. pastoris system.

  1. Patterns of tarnished plant bug (Heteroptera: Miridae) resistance to pyrethroid insecticides in the lower Mississippi Delta for 2008-2015: Linkage to pyrethroid use and cotton insect management

    Science.gov (United States)

    Populations of tarnished plant bug (Lygus lineolaris (Palisot de Beauvois)) from the Lower Mississippi Delta regions of Arkansas, Louisiana and Mississippi were evaluated from 2008 through 2015 for susceptibility to pyrethroid insecticides using a diagnostic-dose assay with permethrin developed by S...

  2. Environmentally Relevant Mixing Ratios in Cumulative Assessments: A Study of the Kinetics of Pyrethroids and Their Ester Cleavage Metabolites in Blood and Brain; and the Effect of a Pyrethroid Mixture on the Motor Activity of Rats

    Science.gov (United States)

    National surveys of United States households and child care centers have demonstrated that pyrethroids are widely distributed in indoor habited dwellings and this suggests that co-exposure to multiple pyrethroids occurs in nonoccupational settings. The purpose of this research wa...

  3. Environmentally-Relevant Mixtures in Cumulative Assessments: An Acute Study of Toxicokinetics and Effects on Motor Activity in Rats Exposed to a Mixture of Pyrethroids

    Science.gov (United States)

    Due to extensive use, human exposure to multiple pyrethroid insecticides occurs frequently. Studies of pyrethroid neurotoxicity suggest a common mode of toxicity and that pyrethroids should be considered cumulatively to model risk. The objective of this work was to use a pyrethro...

  4. Alternative treatments for indoor residual spraying for malaria control in a village with pyrethroid- and DDT-resistant vectors in The Gambia

    NARCIS (Netherlands)

    Tangena, J.A.A.; Adiamoh, M.; Alessandro, D' U.; Jarju, L.; Jawara, M.; Jeffries, D.; Malik, N.; Nwakanma, D.; Kaur, H.; Takken, W.; Lindsay, S.W.; Pinder, M.

    2013-01-01

    Background: Malaria vector control is threatened by resistance to pyrethroids, the only class of insecticides used for treating bed nets. The second major vector control method is indoor residual spraying with pyrethroids or the organochloride DDT. However, resistance to pyrethroids frequently

  5. Hydrolysis of Pyrethroids by Human and Rat Tissues: Examination of Intestinal, Liver and Serum Carboxylesterases

    Science.gov (United States)

    Crow, J. Allen; Borazjani, Abdolsamad; Potter, Philip M.; Ross, Matthew K.

    2009-01-01

    Hydrolytic metabolism of pyrethroid insecticides in humans is one of the major catabolic pathways that clear these compounds from the body. Rodent models are often used to determine the disposition and clearance rates of these esterified compounds. In this study the distribution and activities of esterases that catalyze pyrethroid metabolism have been investigated in vitro using several human and rat tissues, including small intestine, liver, and serum. The major esterase in human intestine is carboxylesterase 2 (hCE2). We found that the pyrethroid trans-permethrin is effectively hydrolyzed by a sample of pooled human intestinal microsomes (5 individuals), while deltamethrin and bioresmethrin are not. This result correlates well with the substrate specificity of recombinant hCE2 enzyme. In contrast, a sample of pooled rat intestinal microsomes (5 animals) hydrolyze trans-permethrin 4.5-fold slower than the sample of human intestinal microsomes. Furthermore, it is demonstrated that pooled samples of cytosol from human or rat liver are ~2-fold less hydrolytically active (normalized per mg protein) than the corresponding microsomal fraction toward pyrethroid substrates; however, the cytosolic fractions do have significant amounts (~40%) of the total esteratic activity. Moreover, a 6-fold interindividual variation in carboxylesterase 1 protein expression in human hepatic cytosols was observed. Human serum was shown to lack pyrethroid hydrolytic activity, but rat serum has hydrolytic activity that is attributed to a single CE isozyme. We purified the serum CE enzyme to homogeneity to determine its contribution to pyrethroid metabolism in the rat. Both trans-permethrin and bioresmethrin were effectively cleaved by this serum CE, but deltamethrin, esfenvalerate, alpha-cypermethrin, and cis-permethrin were slowly hydrolyzed. Lastly, two model lipase enzymes were examined for their ability to hydrolyze pyrethroids. However, no hydrolysis products could be detected. Together

  6. Pyrethroids in house dust from the homes of farm worker families in the MICASA study.

    Science.gov (United States)

    Trunnelle, Kelly J; Bennett, Deborah H; Tancredi, Daniel J; Gee, Shirley J; Stoecklin-Marois, Maria T; Hennessy-Burt, Tamara E; Hammock, Bruce D; Schenker, Marc B

    2013-11-01

    Indoor pesticide exposure is a growing concern, particularly for pyrethroids, a commonly used class of pesticides. Pyrethroid concentrations may be especially high in homes of immigrant farm worker families, who often live in close proximity to agricultural fields and are faced with poor housing conditions, potentially causing high pest infestation and pesticide use. We investigate levels of pyrethroids in the house dust of farm worker family homes in a study of mothers and children living in Mendota, CA, within the population-based Mexican Immigration to California: Agricultural Safety and Acculturation (MICASA) Study. We present pesticide use data and levels of pyrethroid pesticides in indoor dust collected in 2009 as measured by questionnaires and a GC/MS analysis of the pyrethroids cis- and trans-permethrin, cypermethrin, deltamethrin, esfenvalerate and resmethrin in single dust samples collected from 55 households. Cis- and trans-permethrin had the highest detection frequencies at 67%, with median concentrations of 244 and 172ng/g dust, respectively. Cypermethrin was detected in 52% of the homes and had a median concentration of 186ng/g dust. Esfenvalerate, resmethrin and deltamethrin were detected in less than half the samples. We compared the pyrethroid concentrations found in our study to other studies looking at both rural and urban homes and daycares. Lower detection frequencies and/or lower median concentrations of cis- and trans-permethrin and cypermethrin were observed in our study as compared to those studies. However, deltamethrin, esfenvalerate and resmethrin were detected more frequently in the house dust from our study than in the other studies. Because households whose children had higher urinary pyrethroid metabolite levels were more likely to be analyzed in this study, a positive bias in our estimates of household pyrethroid levels may be expected. A positive association was observed with reported outdoor pesticide use and cypermethrin levels

  7. Hydrolysis of pyrethroids by human and rat tissues: Examination of intestinal, liver and serum carboxylesterases

    International Nuclear Information System (INIS)

    Crow, J. Allen; Borazjani, Abdolsamad; Potter, Philip M.; Ross, Matthew K.

    2007-01-01

    Hydrolytic metabolism of pyrethroid insecticides in humans is one of the major catabolic pathways that clear these compounds from the body. Rodent models are often used to determine the disposition and clearance rates of these esterified compounds. In this study the distribution and activities of esterases that catalyze pyrethroid metabolism have been investigated in vitro using several human and rat tissues, including small intestine, liver and serum. The major esterase in human intestine is carboxylesterase 2 (hCE2). We found that the pyrethroid trans-permethrin is effectively hydrolyzed by a sample of pooled human intestinal microsomes (5 individuals), while deltamethrin and bioresmethrin are not. This result correlates well with the substrate specificity of recombinant hCE2 enzyme. In contrast, a sample of pooled rat intestinal microsomes (5 animals) hydrolyze trans-permethrin 4.5-fold slower than the sample of human intestinal microsomes. Furthermore, it is demonstrated that pooled samples of cytosol from human or rat liver are ∼ 2-fold less hydrolytically active (normalized per mg protein) than the corresponding microsomal fraction toward pyrethroid substrates; however, the cytosolic fractions do have significant amounts (∼ 40%) of the total esteratic activity. Moreover, a 6-fold interindividual variation in carboxylesterase 1 protein expression in human hepatic cytosols was observed. Human serum was shown to lack pyrethroid hydrolytic activity, but rat serum has hydrolytic activity that is attributed to a single CE isozyme. We purified the serum CE enzyme to homogeneity to determine its contribution to pyrethroid metabolism in the rat. Both trans-permethrin and bioresmethrin were effectively cleaved by this serum CE, but deltamethrin, esfenvalerate, alpha-cypermethrin and cis-permethrin were slowly hydrolyzed. Lastly, two model lipase enzymes were examined for their ability to hydrolyze pyrethroids. However, no hydrolysis products could be detected

  8. Comparative toxicity of pyrethroid insecticides to two estuarine crustacean species, Americamysis bahia and Palaemonetes pugio.

    Science.gov (United States)

    DeLorenzo, Marie E; Key, Peter B; Chung, Katy W; Sapozhnikova, Yelena; Fulton, Michael H

    2014-10-01

    Pyrethroid insecticides are widely used on agricultural crops, as well as for nurseries, golf courses, urban structural and landscaping sites, residential home and garden pest control, and mosquito abatement. Evaluation of sensitive marine and estuarine species is essential for the development of toxicity testing and risk-assessment protocols. Two estuarine crustacean species, Americamysis bahia (mysids) and Palaemonetes pugio (grass shrimp), were tested with the commonly used pyrethroid compounds, lambda-cyhalothrin, permethrin, cypermethrin, deltamethrin, and phenothrin. Sensitivities of adult and larval grass shrimp and 7-day-old mysids were compared using standard 96-h LC50 bioassay protocols. Adult and larval grass shrimp were more sensitive than the mysids to all the pyrethroids tested. Larval grass shrimp were approximately 18-fold more sensitive to lambda-cyhalothrin than the mysids. Larval grass shrimp were similar in sensitivity to adult grass shrimp for cypermethrin, deltamethrin, and phenothrin, but larvae were approximately twice as sensitive to lambda-cyhalothrin and permethrin as adult shrimp. Acute toxicity to estuarine crustaceans occurred at low nanogram per liter concentrations of some pyrethroids, illustrating the need for careful regulation of the use of pyrethroid compounds in the coastal zone. Copyright © 2013 Wiley Periodicals, Inc., a Wiley company.

  9. New Pyrethroids for Use Against Tuta Absoluta (Lepidoptera: Gelechiidae): Their Toxicity and Control Speed.

    Science.gov (United States)

    Moreno, Shaiene C; Silvério, Flaviano O; Picanço, Marcelo C; Alvarenga, Elson S; Pereira, Renata R; Santana Júnior, Paulo A; Silva, Gerson A

    2017-09-01

    Insect pests are responsible for major losses in crop productivity, and insecticides are the main tools used to control these organisms. There is increasing demand for new products for pest management. Therefore, the aim of this study was to assess the toxicity of pyrethroids with acid moiety modifications to measure the insecticidal activity of these compounds on Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). First, we synthesized E/Z mixtures of five pyrethroids: [9], [10], [11], [12], and [13]. Then, we separated the cis and trans pyrethroid isomers of [9], [10], [11], and [12]. We assessed the toxicity of these compounds against T. absoluta. The E/Z mixtures of the five pyrethroids (30 µg of substance per mg-1 of insect) caused high (100%) and rapid (pyrethroid [10] was the most toxic to T. absoluta, causing mortality similar to permethrin. The other isomers were less powerful than permethrin. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America.

  10. Infestation by pyrethroids resistant bed bugs in the suburb of Paris, France

    Directory of Open Access Journals (Sweden)

    Durand R.

    2012-11-01

    Full Text Available Bed bugs are hematophagous insects responsible for a re-emerging and challenging indoor pest in many countries. Bed bugs infestations may have health consequences including nuisance biting, cutaneous and systemic reactions. This resurgence can probably be attributed to factors such as increased international travel and development of resistance against insecticides. Resistance against pyrethroids has been reported several times from the USA and rarely in Europe. In France, very few data on bed bugs are available. The present study aimed to assess the infestation by bed bugs of a complex of two high-rise apartment buildings in the suburb of Paris and to evaluate their susceptibility to pyrethroid insecticides. We inspected for bed bugs 192 out of 198 apartments units (97% and interviewed their residents. 76 (39.6% apartments were infested. Among the 97 residents living in infested apartments, 53 (54.6% reported bed bug bites. A total of 564 bed bugs were collected in the infested units. Bioassays showed that 54 out of 143 bed bugs were resistant to pyrethroids (37.8%; 95% confidence interval: 29.9-45.7%. DNA sequencing showed that all bed bugs tested (n = 124 had homozygous L925I kdr-like gene mutation. The level of pyrethroid resistance found indicates that this phenomenon was already established in the site and prompts the need to reevaluate the wide use of pyrethroids to control bed bugs.

  11. Control of pyrethroid-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin.

    Science.gov (United States)

    N'Guessan, Raphael; Boko, Pelagie; Odjo, Abiba; Knols, Bart; Akogbeto, Martin; Rowland, Mark

    2009-04-01

    To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance. Eight-week trial conducted in experimental huts. Indoor residual spraying killed 82.9% of An. gambiae overall (mean mortality: 79.5%) compared to 53.5% overall (mean mortality: 61.7%) in the hut containing the lower dosed ITN. Analysis of data on a fortnightly basis showed high levels of mosquito mortality and blood-feeding inhibition during the first few weeks after treatment. Control of C. quinquefasciatus by the IRS and ITN interventions showed a similar trend to that of An. gambiae and though the average level of mortality was lower it was still much higher than with pyrethroid treatments against this population. Chlorfenapyr's reputation for being rather slow acting was evident particularly at lower dosages. The treatments showed no evidence of excito-repellent activity in this trial. Chlorfenapyr has the potential to control pyrethroid resistant populations of A. gambiae. There is a need to develop long-lasting formulations of chlorfenapyr to prolong its residual life on nets and sprayed surfaces. On nets it could be combined with a contact irritant pyrethroid to give improved protection against mosquito biting while killing pyrethroid-resistant mosquitoes that come into contact with the net.

  12. Temperature as a toxicity identification evaluation tool for pyrethroid insecticides: toxicokinetic confirmation.

    Science.gov (United States)

    Harwood, Amanda D; You, Jing; Lydy, Michael J

    2009-05-01

    Toxicity identification evaluation (TIE) methods can be used to identify toxic compounds in environmental samples using a variety of laboratory techniques. Whereas TIEs exist for nonpolar organics, relatively few methods are established for individual contaminant classes. Toxicity identification evaluations have shown pesticides to be the cause of toxicity in agricultural waters and effluents, and more recent studies have shown that the insecticide class of concern is pyrethroids. The primary objectives of the present study were to confirm a temperature TIE model and mechanistically explain these trends. This was achieved by comparing the relative toxicity and influence of temperature (13 vs. 23 degrees C) on Chironomus dilutus exposed to four insecticides, including two pyrethroids, an organophosphate, and an organochlorine, and then explaining these changes using toxicokinetics. A 10 degrees C temperature decrease increased the toxicity of pyrethroids and DDT but decreased the toxicity of chlorpyrifos. The decrease in chlorpyrifos toxicity was driven primarily by the reduction of the formation of more toxic products via decreased biotransformation. The increase in DDT toxicity, in contrast, can be attributed to increased nerve sensitivity at 13 versus 23 degrees C. The pyrethroid toxicity change, however, resulted from a combination of increased accumulation of parent compound and increased nerve sensitivity, exacerbating the toxicity of pyrethroids at 13 degrees C. These trends also held true in sediment exposures with chlorpyrifos and permethrin, indicating that water-only exposures were adequate substitutes for examining this mechanism.

  13. Toxic heritage: Maternal transfer of pyrethroid insecticides and sunscreen agents in dolphins from Brazil

    International Nuclear Information System (INIS)

    Alonso, Mariana B.; Feo, Maria Luisa; Corcellas, Cayo; Gago-Ferrero, Pablo; Bertozzi, Carolina P.; Marigo, Juliana; Flach, Leonardo; Meirelles, Ana Carolina O.; Carvalho, Vitor L.; Azevedo, Alexandre F.; Torres, João Paulo M.

    2015-01-01

    Pyrethroids (PYR) and UV filters (UVF) were investigated in tissues of paired mother-fetus dolphins from Brazilian coast in order to investigate the possibility of maternal transfer of these emerging contaminants. Comparison of PYR and UVF concentrations in maternal and fetal blubber revealed Franciscana transferred efficiently both contaminants to fetuses (F/M > 1) and Guiana dolphin transferred efficiently PYR to fetuses (F/M > 1) different than UVF (F/M < 1). PYR and UVF concentrations in fetuses were the highest-ever reported in biota (up to 6640 and 11,530 ng/g lw, respectively). Muscle was the organ with the highest PYR and UVF concentrations (p < 0.001), suggesting that these two classes of emerging contaminants may have more affinity for proteins than for lipids. The high PYR and UVF concentrations found in fetuses demonstrate these compounds are efficiently transferred through placenta. This study is the first to report maternal transfer of pyrethroids and UV filters in marine mammals. - Highlights: • First time maternal transfer of pyrethroids and UV filters in mammals was reported. • Pollutants in fetus tissues characterize their transplacental transfer. • Fetuses had pyrethroid and UV filter levels 10 times higher than their mothers. • Muscle was the organ presented with the highest concentrations of PYR and UVF. - Pyrethroids and UV filter concentrations in fetus and mother dolphin tissues demonstrated placenta and milk transfer in marine mammals.

  14. Organophosphate and pyrethroid hydrolase activities of mutant Esterases from the cotton bollworm Helicoverpa armigera.

    Science.gov (United States)

    Li, Yongqiang; Farnsworth, Claire A; Coppin, Chris W; Teese, Mark G; Liu, Jian-Wei; Scott, Colin; Zhang, Xing; Russell, Robyn J; Oakeshott, John G

    2013-01-01

    Two mutations have been found in five closely related insect esterases (from four higher Diptera and a hymenopteran) which each confer organophosphate (OP) hydrolase activity on the enzyme and OP resistance on the insect. One mutation converts a Glycine to an Aspartate, and the other converts a Tryptophan to a Leucine in the enzymes' active site. One of the dipteran enzymes with the Leucine mutation also shows enhanced activity against pyrethroids. Introduction of the two mutations in vitro into eight esterases from six other widely separated insect groups has also been reported to increase substantially the OP hydrolase activity of most of them. These data suggest that the two mutations could contribute to OP, and possibly pyrethroid, resistance in a variety of insects. We therefore introduced them in vitro into eight Helicoverpa armigera esterases from a clade that has already been implicated in OP and pyrethroid resistance. We found that they do not generally enhance either OP or pyrethroid hydrolysis in these esterases but the Aspartate mutation did increase OP hydrolysis in one enzyme by about 14 fold and the Leucine mutation caused a 4-6 fold increase in activity (more in one case) of another three against some of the most insecticidal isomers of fenvalerate and cypermethrin. The Aspartate enzyme and one of the Leucine enzymes occur in regions of the H. armigera esterase isozyme profile that have been previously implicated in OP and pyrethroid resistance, respectively.

  15. Organophosphate and pyrethroid hydrolase activities of mutant Esterases from the cotton bollworm Helicoverpa armigera.

    Directory of Open Access Journals (Sweden)

    Yongqiang Li

    Full Text Available Two mutations have been found in five closely related insect esterases (from four higher Diptera and a hymenopteran which each confer organophosphate (OP hydrolase activity on the enzyme and OP resistance on the insect. One mutation converts a Glycine to an Aspartate, and the other converts a Tryptophan to a Leucine in the enzymes' active site. One of the dipteran enzymes with the Leucine mutation also shows enhanced activity against pyrethroids. Introduction of the two mutations in vitro into eight esterases from six other widely separated insect groups has also been reported to increase substantially the OP hydrolase activity of most of them. These data suggest that the two mutations could contribute to OP, and possibly pyrethroid, resistance in a variety of insects. We therefore introduced them in vitro into eight Helicoverpa armigera esterases from a clade that has already been implicated in OP and pyrethroid resistance. We found that they do not generally enhance either OP or pyrethroid hydrolysis in these esterases but the Aspartate mutation did increase OP hydrolysis in one enzyme by about 14 fold and the Leucine mutation caused a 4-6 fold increase in activity (more in one case of another three against some of the most insecticidal isomers of fenvalerate and cypermethrin. The Aspartate enzyme and one of the Leucine enzymes occur in regions of the H. armigera esterase isozyme profile that have been previously implicated in OP and pyrethroid resistance, respectively.

  16. Temporal variability of pyrethroid metabolite levels in bedtime, morning, and 24-hr urine samples for 50 adults in North Carolina

    Science.gov (United States)

    Pyrethroid insecticides are widely used to control insects in both agricultural and residential settings worldwide. Few data are available on the temporal variability of pyrethroid metabolites in the urine of non-occupationally exposed adults. In this work, we describe the study ...

  17. The pyrethroid metabolites 3-phenoxybenzoic acid and 3-phenoxybenzyl alcohol do not exhibit estrogenic activity in the MCF-7 human breast carcinoma cell line or Sprague-Dawley rats

    International Nuclear Information System (INIS)

    Laffin, Brian; Chavez, Marco; Pine, Michelle

    2010-01-01

    Synthetic pyrethroids are one of the most frequently and widely used class of insecticides, primarily because they have a higher insect to mammalian toxicity ratio than organochlorines or organophosphates. The basic structure of pyrethroids can be characterized as an acid joined to an alcohol by an ester bond. Pyrethroid degradation occurs through either oxidation at one or more sites located in the alcohol or acid moieties or hydrolysis at the central ester bond, the latter reaction being important for mammalian metabolism of most pyrethroids. The primary alcohol liberated from the ester cleavage is hydroxylated to 3-phenoxybenzyl alcohol, which for most pyrethroids is then oxidized to 3-phenoxybenzoic acid. These products may then be conjugated with amino acids, sulfates, sugars, or sugar acids. In vitro studies have suggested that some of the pyrethroids may have estrogenic activity. Interestingly, the chemical structure of specific pyrethroid metabolites indicates that they may be more likely to interact with the estrogen receptor than the parent compounds. Two of the pyrethroid metabolites, 3-phenoxybenzoic acid (3PBA) and 3-phenoxybenzyl alcohol (3PBalc) have been reported to have endocrine activity using a yeast based assay. 3PBAlc exhibited estrogenic activity with reported EC 50 s of 6.67 x 10 -6 and 2 x 10 -5 while 3PBAcid exhibited anti-estrogenic activity with a calculated IC 50 of 6.5 x 10 -5 . To determine if the metabolites were able to cause the same effects in a mammalian system, the estrogen-dependent cell line, MCF-7, was utilized. Cells were treated with 1.0, 10.0 or 100.0 μM concentrations of each metabolite and cytotoxicity was assessed. The two lowest concentrations of both metabolites did not induce cell death and even appeared to increase proliferation over that of the control cells. However, when cellular proliferation was measured using a Coulter counter neither metabolite stimulated proliferation (1.0 nM, 10.0 nM, or 10.0 μM) or

  18. Hippocampal ER stress and learning deficits following repeated pyrethroid exposure.

    Science.gov (United States)

    Hossain, Muhammad M; DiCicco-Bloom, Emanuel; Richardson, Jason R

    2015-01-01

    Endoplasmic reticulum (ER) stress is implicated as a significant contributor to neurodegeneration and cognitive dysfunction. Previously, we reported that the widely used pyrethroid pesticide deltamethrin causes ER stress-mediated apoptosis in SK-N-AS neuroblastoma cells. Whether or not this occurs in vivo remains unknown. Here, we demonstrate that repeated deltamethrin exposure (3 mg/kg every 3 days for 60 days) causes hippocampal ER stress and learning deficits in adult mice. Repeated exposure to deltamethrin caused ER stress in the hippocampus as indicated by increased levels of C/EBP-homologous protein (131%) and glucose-regulated protein 78 (96%). This was accompanied by increased levels of caspase-12 (110%) and activated caspase-3 (50%). To determine whether these effects resulted in learning deficits, hippocampal-dependent learning was evaluated using the Morris water maze. Deltamethrin-treated animals exhibited profound deficits in the acquisition of learning. We also found that deltamethrin exposure resulted in decreased BrdU-positive cells (37%) in the dentate gyrus of the hippocampus, suggesting potential impairment of hippocampal neurogenesis. Collectively, these results demonstrate that repeated deltamethrin exposure leads to ER stress, apoptotic cell death in the hippocampus, and deficits in hippocampal precursor proliferation, which is associated with learning deficits. © The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  19. Trait characteristics determine pyrethroid sensitivity in non-standard test species of freshwater macroinvertebrates – A reality check

    DEFF Research Database (Denmark)

    Wiberg-Larsen, Peter; Graeber, Daniel; Baattrup-Pedersen, Annette

    2016-01-01

    We exposed 34 species of stream macroinvertebrates, representing 29 families, to a 90 min pulse of the pyrethroid λ-cyhalothrin. For 28 of these species, no pyrethroid ecotoxicity data exist. We recorded mortality rates 6 days post-exposure, and the behavioral response to pyrethroid exposure...... and the preference for coarse substrates significantly influenced the LC50 for arthropod species, with the combination of small individuals and strong preference for coarse substrates indicating higher pyrethroid sensitivity. Our study highlights that existing pesticide ecotoxicity data should be extrapolated...... to untested species with caution and that actual body size (not maximum potential body size, as is usually available in traits databases) and habitat preference are central parameters determining species sensitivities to pyrethroids....

  20. Molecular cloning and characterization of a novel pyrethroid-hydrolyzing esterase originating from the Metagenome

    Directory of Open Access Journals (Sweden)

    Liu Yu

    2008-12-01

    Full Text Available Abstract Background Pyrethroids and pyrethrins are widely used insecticides. Extensive applications not only result in pest resistance to these insecticides, but also may lead to environmental issues and human exposure. Numerous studies have shown that very high exposure to pyrethroids might cause potential problems to man and aquatic organisms. Therefore, it is important to develop a rapid and efficient disposal process to eliminate or minimize contamination of surface water, groundwater and agricultural products by pyrethroid insecticides. Bioremediation is considered to be a reliable and cost-effective technique for pesticides abatement and a major factor determining the fate of pyrethroid pesticides in the environment, and suitable esterase is expected to be useful for potential application for detoxification of pyrethroid residues. Soil is a complex environment considered as one of the main reservoirs of microbial diversity on the planet. However, most of the microorganisms in nature are inaccessible as they are uncultivable in the laboratory. Metagenomic approaches provide a powerful tool for accessing novel valuable genetic resources (novel enzymes and developing various biotechnological applications. Results The pyrethroid pesticides residues on foods and the environmental contamination are a public safety concern. Pretreatment with pyrethroid-hydrolyzing esterase has the potential to alleviate the conditions. To this end, a pyrethroid-hydrolyzing esterase gene was successfully cloned using metagenomic DNA combined with activity-based functional screening from soil, sequence analysis of the DNA responsible for the pye3 gene revealed an open reading frame of 819 bp encoding for a protein of 272 amino acid residues. Extensive multiple sequence alignments of the deduced amino acid of Pye3 with the most homologous carboxylesterases revealed moderate identity (45–49%. The recombinant Pye3 was heterologously expressed in E. coli BL21(DE3

  1. Target-site resistance to pyrethroids in European populations of pollen beetle, Meligethes aeneus F

    DEFF Research Database (Denmark)

    Nauen, Ralf; Zimmer, Christoph T; Andrews, Melanie

    2012-01-01

    detected a single nucleotide change that results in an amino acid substitution (L1014F) within the domain IIS6 region of the channel protein. The L1014F mutation, often termed kdr, has been found in several other insect pests and is known to confer moderate levels of resistance to pyrethroids. We developed......Pollen beetle, Meligethes aeneus F. (Coleoptera: Nitidulidae) is a major univoltine pest of oilseed rape in many European countries. Winter oilseed rape is cultivated on several million hectares in Europe and the continuous use of pyrethroid insecticides to control pollen beetle populations has...... resulted in high selection pressure and subsequent development of resistance. Resistance to pyrethroid insecticides in this pest is now widespread and the levels of resistance are often sufficient to result in field control failures at recommended application rates. Recently, metabolic resistance mediated...

  2. Distinct roles of the DmNav and DSC1 channels in the action of DDT and pyrethroids.

    Science.gov (United States)

    Rinkevich, Frank D; Du, Yuzhe; Tolinski, Josh; Ueda, Atsushi; Wu, Chun-Fang; Zhorov, Boris S; Dong, Ke

    2015-03-01

    Voltage-gated sodium channels (Nav channels) are critical for electrical signaling in the nervous system and are the primary targets of the insecticides DDT and pyrethroids. In Drosophila melanogaster, besides the canonical Nav channel, Para (also called DmNav), there is a sodium channel-like cation channel called DSC1 (Drosophila sodium channel 1). Temperature-sensitive paralytic mutations in DmNav (para(ts)) confer resistance to DDT and pyrethroids, whereas DSC1 knockout flies exhibit enhanced sensitivity to pyrethroids. To further define the roles and interaction of DmNav and DSC1 channels in DDT and pyrethroid neurotoxicology, we generated a DmNav/DSC1 double mutant line by introducing a para(ts1) allele (carrying the I265N mutation) into a DSC1 knockout line. We confirmed that the I265N mutation reduced the sensitivity to two pyrethroids, permethrin and deltamethrin of a DmNav variant expressed in Xenopus oocytes. Computer modeling predicts that the I265N mutation confers pyrethroid resistance by allosterically altering the second pyrethroid receptor site on the DmNav channel. Furthermore, we found that I265N-mediated pyrethroid resistance in para(ts1) mutant flies was almost completely abolished in para(ts1);DSC1(-/-) double mutant flies. Unexpectedly, however, the DSC1 knockout flies were less sensitive to DDT, compared to the control flies (w(1118A)), and the para(ts1);DSC1(-/-) double mutant flies were even more resistant to DDT compared to the DSC1 knockout or para(ts1) mutant. Our findings revealed distinct roles of the DmNav and DSC1 channels in the neurotoxicology of DDT vs. pyrethroids and implicate the exciting possibility of using DSC1 channel blockers or modifiers in the management of pyrethroid resistance. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Pyrethroids differentially alter voltage-gated sodium channels from the honeybee central olfactory neurons.

    Science.gov (United States)

    Kadala, Aklesso; Charreton, Mercedes; Jakob, Ingrid; Cens, Thierry; Rousset, Matthieu; Chahine, Mohamed; Le Conte, Yves; Charnet, Pierre; Collet, Claude

    2014-01-01

    The sensitivity of neurons from the honey bee olfactory system to pyrethroid insecticides was studied using the patch-clamp technique on central 'antennal lobe neurons' (ALNs) in cell culture. In these neurons, the voltage-dependent sodium currents are characterized by negative potential for activation, fast kinetics of activation and inactivation, and the presence of cumulative inactivation during train of depolarizations. Perfusion of pyrethroids on these ALN neurons submitted to repetitive stimulations induced (1) an acceleration of cumulative inactivation, and (2) a marked slowing of the tail current recorded upon repolarization. Cypermethrin and permethrin accelerated cumulative inactivation of the sodium current peak in a similar manner and tetramethrin was even more effective. The slow-down of channel deactivation was markedly dependent on the type of pyrethroid. With cypermethrin, a progressive increase of the tail current amplitude along with successive stimulations reveals a traditionally described use-dependent recruitment of modified sodium channels. However, an unexpected decrease in this tail current was revealed with tetramethrin. If one considers the calculated percentage of modified channels as an index of pyrethroids effects, ALNs are significantly more susceptible to tetramethrin than to permethrin or cypermethrin for a single depolarization, but this difference attenuates with repetitive activity. Further comparison with peripheral neurons from antennae suggest that these modifications are neuron type specific. Modeling the sodium channel as a multi-state channel with fast and slow inactivation allows to underline the effects of pyrethroids on a set of rate constants connecting open and inactivated conformations, and give some insights to their specificity. Altogether, our results revealed a differential sensitivity of central olfactory neurons to pyrethroids that emphasize the ability for these compounds to impair detection and processing of

  4. The effect of environmental exposure to pyrethroids and DNA damage in human sperm.

    Science.gov (United States)

    Jurewicz, Joanna; Radwan, Michał; Wielgomas, Bartosz; Sobala, Wojciech; Piskunowicz, Marta; Radwan, Paweł; Bochenek, Michał; Hanke, Wojciech

    2015-01-01

    The present study was designed to investigate whether environmental exposure to pyrethroids was associated with sperm DNA damage. Between January 2008 and April 2011 286 men under 45 years of age with a normal sperm concentration of 15-300 10(6)/ml [WHO 2010] were recruited from an infertility clinic in Lodz, Poland. Participants were interviewed and provided urine, saliva, and semen samples. The pyrethroids metabolites: 3-phenoxybenzoic acid (3PBA), cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (CDCCA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (TDCCA), and cis-2,2-dibromovinyl-2,2-dimethylcyclopropane-carboxylic acid (DBCA) were analyzed in the urine using a validated gas chromatography ion-tap mass spectrometry method. Sperm DNA damage was assessed using a flow cytometry based on sperm chromatin structure assay (SCSA). A positive association was observed between CDCCA >50th percentile and the percentage of medium DNA fragmentation index (M DFI) and percentage of immature sperms (HDS) (p = 0.04, p = 0.04 respectively). The level of 3PBA >50th percentile in urine was positively related to the percentage of high DNA fragmentation index (H DFI) (p = 0.03). The TDCCA, DBCA levels, and the sum of pyrethroid metabolites were not associated with any sperm DNA damage measures. Our results suggest that environmental pyrethroid exposure may affect sperm DNA damage measures index indicated the reproductive effects of pyrethroid exposure on adult men. In view of the importance of human reproductive health and the widespread usage of pyrethroids, it is important to further investigate these correlations.

  5. Bendiocarb, a potential alternative against pyrethroid resistant Anopheles gambiae in Benin, West Africa

    Directory of Open Access Journals (Sweden)

    Irish Seth

    2010-07-01

    Full Text Available Abstract Background Anopheles gambiae, the main malaria vector in Benin has developed high level of resistance to pyrethroid insecticides, which is a serious concern to the future use of long-lasting insecticidal nets (LLIN and indoor residual spraying (IRS. In this context, one of the pathways available for malaria vector control would be to investigate alternative classes of insecticides with different mode of action than that of pyrethroids. The goal of this study was to evaluate under field conditions the efficacy of a carbamate (bendiocarb and an organophosphate (fenitrothion against pyrethroid-resistant An. gambiae s.s. Methods Wild populations and females from laboratory colonies of five days old An. gambiae were bio-assayed during this study. Two pyrethroids (deltamethrin and alphacypermethrin, an organophosphate (fenitrothion, a carbamate (bendiocarb and a mixture of an organophosphate (chlorpyriphos + a pyrethroid deltamethrin were compared in experimental huts as IRS treatments. Insecticides were applied in the huts using a hand-operated compression sprayer. The deterrency, exophily, blood feeding rate and mortality induced by these insecticides against An. gambiae were compared to the untreated control huts. Results Deltamethrin, alphacypermethrin and bendiocarb treatment significantly reduced mosquito entry into the huts (p An. gambiae (in the first month and 77.8% (in the fourth month. Bendiocarb and the mixture chlorpyriphos/deltamethrin mortality rates ranged from 97.9 to 100% the first month and 77.7-88% the third month respectively. Conclusion After four months, fenitrothion, bendiocarb and the mixture chlorpyriphos/deltamethrin performed effectively against pyrethroid-resistant Anopheles. These results showed that bendiocarb could be recommended as an effective insecticide for use in IRS operations in Benin, particularly as the mixture chlorpyriphos/deltamethrin does not have WHOPES authorization and complaints were mentioned

  6. Evaluation of pyrethroid exposures in pregnant women from 10 Caribbean countries.

    Science.gov (United States)

    Dewailly, Eric; Forde, Martin; Robertson, Lyndon; Kaddar, Nisrin; Laouan Sidi, Elhadji A; Côté, Suzanne; Gaudreau, Eric; Drescher, Olivia; Ayotte, Pierre

    2014-02-01

    Pyrethroid pesticides are commonly used in tropical regions such as the Caribbean as household insecticides, pet sprays, and where malaria is endemic, impregnated into mosquito-repellent nets. Of particular concern is exposure during pregnancy, as these compounds have the potential to cross the placental barrier and interfere with fetal development, as was shown in limited animal studies. The objective of this study was to evaluate exposure to pyrethroids to pregnant women residing in 10 English-speaking Caribbean countries. Pyrethroid exposures were determined by analyzing five pyrethroid metabolites in urine samples from 295 pregnant women: cis-DBCA, cis-DCCA, trans-DCCA, 3-PBA, and 4-F-3-PBA. Pyrethroid metabolite concentrations in Caribbean pregnant women were generally higher in the 10 Caribbean countries than levels reported for Canadian and U.S. women. In Antigua & Barbuda and Jamaica participants the geometric mean concentrations of cis-DBCA was significantly higher than in the other nine countries together (p<0.0001 and <0.0012 respectively). For cis- and trans-DCCA, only Antigua & Barbuda women differed significantly from participants of the other nine Caribbean countries (p<0.0001). Urinary 4-F-3-PBA and 3-PBA levels were significantly higher in Antigua & Barbuda (p<0.0028 and p<0.0001 respectively) as well as in Grenada (p<0.0001 and p<0.007 respectively). These results indicate extensive use of pyrethroid compounds such as permethrin and cypermethrin in Caribbean households. In Antigua & Barbuda, the data reveals a greater use of deltamethrin. This study underscores the need for Caribbean public health authorities to encourage their populations, and in particular pregnant women, to utilize this class of pesticides more judiciously given the potentially adverse effects of exposure on fetuses and infants. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Biannual monitoring of pyrethroid and neonicotinoid susceptibility in Danish pollen beetle (Meligethes aeneus F.) populations

    DEFF Research Database (Denmark)

    Kaiser, Caroline; Kristensen, Michael; Jensen, Karl-Martin Vagn

    2015-01-01

    The pollen beetle (Meligethes aeneus F.) is a serious pest in the northern countries in oilseed rape. To determine the present level of pyrethroid and neonicotinoid susceptibility of Danish pollen beetle populations, standardized methods recommended by IRAC (Insecticide Resistance Action Committee......, if the resistance level which was determined in 2014 was stable in selected regions. Therefore pollen beetle populations from 14 locations in Denmark and five locations in Germany have been tested. For all tests the standardised methods for pyrethroids, the Adult-vial-test No. 11 and the Adult-vials-test No. 21...

  8. Plant synthetic biology.

    Science.gov (United States)

    Liu, Wusheng; Stewart, C Neal

    2015-05-01

    Plant synthetic biology is an emerging field that combines engineering principles with plant biology toward the design and production of new devices. This emerging field should play an important role in future agriculture for traditional crop improvement, but also in enabling novel bioproduction in plants. In this review we discuss the design cycles of synthetic biology as well as key engineering principles, genetic parts, and computational tools that can be utilized in plant synthetic biology. Some pioneering examples are offered as a demonstration of how synthetic biology can be used to modify plants for specific purposes. These include synthetic sensors, synthetic metabolic pathways, and synthetic genomes. We also speculate about the future of synthetic biology of plants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Development of multifunctional metabolic synergists to suppress the evolution of resistance against pyrethroids in insects that blood feed on humans.

    Science.gov (United States)

    Hardstone, Melissa C; Strycharz, Joseph P; Kim, Junheon; Park, Il-Kwon; Yoon, Kyong Sup; Ahn, Young Joon; Harrington, Laura C; Lee, Si Hyeock; Clark, J Marshall

    2015-06-01

    Pyrethroids are the insecticides of choice when exposure to humans is likely, such as occurs in vector and public-health-related control programs. Unfortunately, the pyrethroids share a common resistance mechanism with dichlorodiphenyltrichloroethane (DDT), knockdown resistance (kdr), and prior extensive use of DDT has predisposed the pyrethroids to cross-resistance via kdr. Given the widespread occurrence of kdr, the use of synergists with pyrethroids is considered to be prudent to guard against the selection of multiply resistant insects. 3-Phenoxybenzyl hexanoate (PBH) was synthesized as a multifunctional pyrethroid synergist that, besides being a surrogate substrate for sequestration/hydrolytic carboxylesterases, now also functions as a substrate for oxidative xenobiotic metabolism. The addition of PBH to permethrin-treated females of the ISOP450 strain of Culex pipiens quinquefasciatus resulted in a threefold increase in synergism, as judged by the synergistic ratio. Similarly, PBH synergized the action of deltamethrin sixfold on females of the common bed bug, Cimex lectularius, and was 2.8-fold more synergistic than piperonyl butoxide (PBO). PBH synergized the action of both type I and type II pyrethroids in a mosquito vector (Cx. p. quinquefasciatus) and in a public-health pest, C. lectularius, respectively, indicating a broad spectrum of action on blood-feeding insects. PBH appears to have residual properties similar to permethrin and is itself non-toxic, unlike PBO, and therefore should be compatible with existing pyrethroid formulations used for insecticide-treated nets and home/residential sprays. © 2014 Society of Chemical Industry.

  10. Synthetic antifreeze peptide

    OpenAIRE

    1991-01-01

    A synthetic antifreeze peptide and a synthetic gene coding for the antifreeze peptide have been produced. The antifreeze peptide has a greater number of repeating amino acid sequences than is present in the native antifreeze peptides from winter flounder upon which the synthetic antifreeze peptide was modeled. Each repeating amino acid sequence has two polar amino acid residues which are spaced a controlled distance apart so that the antifreeze peptide may inhibit ice formation. The synthetic...

  11. [SYNTHETIC PEPTIDE VACCINES].

    Science.gov (United States)

    Sergeyev, O V; Barinsky, I F

    2016-01-01

    An update on the development and trials of synthetic peptide vaccines is reviewed. The review considers the successful examples of specific protection as a result of immunization with synthetic peptides using various protocols. The importance of conformation for the immunogenicity of the peptide is pointed out. An alternative strategy of the protection of the organism against the infection using synthetic peptides is suggested.

  12. Frequency-dependent effects of the pyrethroid insecticide decamethrin in frog myelinated nerve fibres

    NARCIS (Netherlands)

    Vijverberg, H.P.M.; Bercken, J. van den

    1979-01-01

    The pyrethroid insectide decamethrin (10−6M) caused a frequency-dependent depression of the action potential in frog myelinated nerve fibres which was associated with a progressive membrane depolarisation brought about by summation of depolarising after-potentials. Voltage clamp experiments with

  13. Assessing Dietary Exposure to Pyrethroid Insecticides by LCIMS/MS of Food Composites

    Science.gov (United States)

    Method Commercially-obtained vegetables, chips, cereal, meat, and other solid food products were homogenized together to create composited control matrices at 1%, 5%, and 100/0 fat content. Lyophilized homogenates were spiked with 7 pyrethroids, 6 degradation products, bisphen...

  14. Effects of sublethal pyrethroid exposure on host-seeking behavior of female mosquitoes

    Science.gov (United States)

    Adult mosquito control consists of residual application on surfaces and aerial spraying often using pyrethroids, however, not all insects contacting insecticides are killed. Sublethal exposure to neurotoxic compounds can negatively affect sensory organs and reducing the insect’s efficiency of host l...

  15. Acute toxicity of Lambda, Cyhalothrin Pyrethroid (Karate 2.5 EC) on ...

    African Journals Online (AJOL)

    0.4cm were exposed to nominal concentration of lambda, cyhalothrin pyrethroid pesticide (Karate 2.5 EC) at 20 ppm, 40 ppm, 60 ppm, 80 ppm and 100 ppm through a gravimetric toxicant auto delivery system during a continuous flow through ...

  16. Semen quality and the level of reproductive hormones after environmental exposure to pyrethroids.

    Science.gov (United States)

    Radwan, Michał; Jurewicz, Joanna; Wielgomas, Bartosz; Sobala, Wojciech; Piskunowicz, Marta; Radwan, Paweł; Hanke, Wojciech

    2014-11-01

    The aim of this study was to determine whether the environmental exposure to pyrethroids affects semen quality and the level of reproductive hormones in men. The study population consisted of 334 men who attended the infertility clinic for diagnostic purposes and who had normal semen concentration of 15 to 300 mln/mL. Participants were interviewed and provided a semen sample. The pyrethroids metabolites-3-phenoxybenzoic acid (3PBA), cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (CDCCA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (TDCCA), and cis-2,2-dibromovinyl-2,2-dimethylcyclopropane-1-carboxylic acid (DBCA) were analyzed in the urine using a validated gas chromatography ion-trap mass spectrometry method. Urinary pyrethroids metabolites levels were significantly associated with an increase in the percentage of sperm with abnormal morphology and decrease in sperm concentration, the level of testosterone, and computer-aided semen analysis parameters. Environmental pyrethroids exposure may affect semen quality and the level of reproductive hormones.

  17. An amino acid substitution (L925V associated with resistance to pyrethroids in Varroa destructor.

    Directory of Open Access Journals (Sweden)

    Joel González-Cabrera

    Full Text Available The Varroa mite, Varroa destructor, is an important pest of honeybees and has played a prominent role in the decline in bee colony numbers over recent years. Although pyrethroids such as tau-fluvalinate and flumethrin can be highly effective in removing the mites from hives, their intensive use has led to many reports of resistance. To investigate the mechanism of resistance in UK Varroa samples, the transmembrane domain regions of the V. destructor voltage-gated sodium channel (the main target site for pyrethroids were PCR amplified and sequenced from pyrethroid treated/untreated mites collected at several locations in Central/Southern England. A novel amino acid substitution, L925V, was identified that maps to a known hot spot for resistance within the domain IIS5 helix of the channel protein; a region that has also been proposed to form part of the pyrethroid binding site. Using a high throughput diagnostic assay capable of detecting the mutation in individual mites, the L925V substitution was found to correlate well with resistance, being present in all mites that had survived tau-fluvalinate treatment but in only 8 % of control, untreated samples. The potential for using this assay to detect and manage resistance in Varroa-infected hives is discussed.

  18. Pyrethroid Susceptibility Has Been Maintained in the Dengue Vector, Aedes aegypti (Diptera: Culicidae), in Queensland, Australia.

    Science.gov (United States)

    Endersby-Harshman, Nancy M; Wuliandari, Juli Rochmijati; Harshman, Lawrence G; Frohn, Verena; Johnson, Brian J; Ritchie, Scott A; Hoffmann, Ary A

    2017-11-07

    Although pesticide resistance is common in insect vectors of human diseases, the evolution of resistance might be delayed if management practices are adopted that limit selection of resistance alleles. Outbreaks of dengue fever have occurred in Queensland, Australia, since the late 1800s, leading to ongoing attempts to control the mosquito vector, Aedes aegypti (L.). Since the 1990s, pyrethroid insecticides have been used for this purpose, but have been applied in a strategic manner with a variety of delivery methods including indoor residual spraying, lethal ovitraps, and use of insect growth regulators as larvicides. Separate selection experiments on mosquitoes from Queensland using Type I and Type II pyrethroids did not produce resistant lines of Ae. aegypti, and bioassays of field material from Queensland showed only weak tolerance in comparison with a susceptible line. There was no evidence of knockdown resistance (kdr) mutations in Ae. aegypti from Queensland, in stark contrast to the situation in nearby southeast Asia. We suspect that careful management of pyrethroid insecticide use combined with surveillance and interception of exotic incursions has helped to maintain pyrethroid (and particularly kdr-based) susceptibility in Ae. aegypti in Australia. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Control of pyrethroid-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin

    NARCIS (Netherlands)

    N'Guessan, R.; Boko, P.; Odjo, A.; Knols, B.G.J.; Akogbeto, M.; Rowland, M.

    2009-01-01

    Objective To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance. Method Eight-week trial conducted in experimental

  20. Pyrethroid effects on freshwater invertebrates: a meta-analysis of pulse exposures.

    Science.gov (United States)

    Rasmussen, Jes Jessen; Wiberg-Larsen, Peter; Kristensen, Esben Astrup; Cedergreen, Nina; Friberg, Nikolai

    2013-11-01

    Pyrethroids are widely used insecticides that may seriously harm aquatic organisms. Being strongly hydrophobic, pyrethroids in solution occur only in short pulses but may be retained in sediments for longer periods. Consequently, most studies consider the chronic exposure of sediment dwelling organisms. We collected data from 16 studies to determine effect thresholds for stream macroinvertebrates exposed to short pyrethroid pulses evaluating lethal and sublethal ecologically relevant endpoints. Dose-response models showed EC50 for lethality, functional and behavioural endpoints down to 1/100, 1/100 and 1/1000 of the 48 h LC50 for Daphnia magna, respectively. The results indicate that the overall sensitivity of stream macroinvertebrates to pyrethroids may be higher than previously believed. This review shows the relevance of incorporating data on sublethal endpoints and appropriate post-exposure observation periods in future studies. The current risk assessment procedures and the higher tier approach are discussed in the light of our results. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Hypersensitivity Reaction and Acute Respiratory Distress Syndrome in Pyrethroid Poisoning and Role of Steroid Therapy

    Directory of Open Access Journals (Sweden)

    Jisa George

    2015-06-01

    Full Text Available Background: Pyrethroids are generally of low toxicity to humans, but in suicidal poisonings which are usually associated with ingestion of high doses, they lead to severe systemic effects. Case Report: A 30-year old woman presented to emergency department with a history of intentional ingestion of about 15 mL of prallethrin around 3 days earlier. She complained of shortness of breath along with chest pain for the last 2 days. She reported no vomiting or stomach pain prior to presentation to hospital. On chest auscultation, breath sounds were mildly decreased in bilateral infrascapular areas with generalized crepitation. Arterial blood gas analysis revealed respiratory alkalosis. Chest X ray and computed tomography of thorax revealed widespread confluent areas of consolidation with interlobular septal thickening involving bilateral parahilar regions suggestive of acute respiratory distress syndrome (ARDS. The patient did not respond to broad spectrum antibiotic coverage, diuretics and oxygen inhalation. Intravenous methylprednisolone (2 mg/kg/day divided 6 hourly was started and slowly tapered off during the next days. The patient discharged after 3 weeks in good health. Discussion: As pyrethroids can affect sodium channels, the osmotic gradient of alveolar epithelium probably disrupts and therefore, alveolar infiltrations gradually spread over lungs. In addition, there is a possibility of hypersensitivity reactions to pyrethroids, which can cause progressive inflammation and involve respiratory tract in severe cases. Conclusion: Pyrethroid poisoning can lead to ARDS. Steroid therapy may help such patients tide over the pulmonary crisis.

  2. EPA's SHEDS-multimedia model: children's cumulative pyrethroid exposure estimates and evaluation against NHANES biomarker data

    Science.gov (United States)

    The U.S. EPA's SHEDS-Multimedia model was applied to enhance the understanding of children's exposures and doses to multiple pyrethroid pesticides, including major contributing chemicals and pathways. This paper presents combined dietary and residential exposure estimates and cum...

  3. Myopia and Exposure to Organophosphate and Pyrethroid Pesticides in the General United States Population.

    Science.gov (United States)

    Migneron-Foisy, Vincent; Bouchard, Maryse F; Freeman, Ellen E; Saint-Amour, Dave

    2017-09-01

    Previous research suggests that exposure to pesticides might be associated with human myopia, although data were obtained only from highly exposed individuals. The present study aimed to assess whether exposure to organophosphates and pyrethroids in the United States general population was associated with the prevalence of myopia. Data were obtained from the National Health and Nutrition Examination Survey (NHANES, years 1999-2008). One-spot urine samples were used to estimate the concentration of several pesticide metabolites. Exposure data and equivalent spherical refraction errors were available for 5147 and 2911 individuals for organophosphates and pyrethroids, respectively. Multiple logistic regression models were used to assess the relation between log10-transformed urinary levels of pesticide metabolites and the risk of moderate (≤-1 and >-5 diopters [D]) and high myopia (≤-5 D) in adolescents (12- to 19-years old) and young adults (20- to 40-years old). Models were adjusted for sex, age, ethnicity, diabetes, creatinine, cadmium and lead concentrations, and income in both age groups, but also for education level and cigarette and alcohol consumption in the adult group. No association between organophosphates or pyrethroid metabolites and myopia was observed. However, after adjusting for education level and cigarette and alcohol consumption, a statistically significant decreased risk of high myopia in those with a 10-fold increase of dialkyl phosphate metabolites was found in adults but only in men (P organophosphates or pyrethroids do not increase the risk of myopia in the United States general population.

  4. Using a near-infrared spectrometer to estimate the age of Anopheles mosquitoes exposed to pyrethroids

    Science.gov (United States)

    We report on the accuracy of using near-infrared spectroscopy (NIRS) to predict the age of Anopheles mosquitoes reared from wild larvae and a mixed age-wild adult population collected from pit traps after exposure to pyrethroids. The mosquitoes reared from wild larvae were estimated as ,7 or $7 d ol...

  5. Dietary cumulative acute risk assessment of organophosphorus, carbamates and pyrethroids insecticides for the Brazilian population.

    NARCIS (Netherlands)

    Jardim, Andreia Nunes Oliveira; Brito, Alessandra Page; van Donkersgoed, Gerda; Boon, Polly E; Caldas, Eloisa Dutra

    Cumulative acute dietary risk assessments of organophosphorus (OPs), carbamates (CBs) and pyrethroids (PYs) were conducted for the Brazilian population. Residue data for 30786 samples of 30 foods were obtained from two national monitoring programs and one University laboratory, and consumption data

  6. Diversity of knockdown resistance alleles in a single house fly population facilitates adaptation to pyrethroid insecticides.

    Science.gov (United States)

    Kasai, S; Sun, H; Scott, J G

    2017-02-01

    Insecticide use exerts a tremendous selection force on house fly populations, but the frequencies of the initial resistance mutations may not reach high levels if they have a significant fitness cost in the absence of insecticides. However, with the continued use of the same (or similar) insecticides, it is expected that new mutations (conferring equal or greater resistance, but less of a fitness cost) will evolve. Pyrethroid insecticides target the insect voltage sensitive sodium channel (VSSC) and have been widely used for control of house flies at animal production facilities for more than three decades. There are three Vssc mutations known that cause resistance to pyrethroids in house flies: knockdown resistance (kdr, L1014F), kdr-his (L1014H) and super-kdr (M918T + L1014F). Whether or not there are any new mutations in house fly populations has not been examined for decades. We collected house flies from a dairy in Kansas (USA) and selected this population for three generations. We discovered multiple new Vssc alleles, including two that give very high levels of resistance to most pyrethroids. The importance of these findings to understanding the evolution of insecticide resistance, designing appropriate resistance monitoring and management schemes, and the future of pyrethroids for house fly control are discussed. © 2016 The Royal Entomological Society.

  7. Sublethal effects of pyrethroid and neonicotinoid insecticides on Iphiseiodes zuluagai Denmark and Muma (Mesostigmata: Phytoseiidae).

    Science.gov (United States)

    Zanuzo Zanardi, Odimar; Pavan Bordini, Gabriela; Aparecida Franco, Aline; Jacob, Cynthia Renata Oliveira; Takao Yamamoto, Pedro

    2017-11-01

    The predator mite Iphiseiodes zuluagai Denmark & Muma is an important biological-control agent of mite pests, and it is one of the most common species found in citrus orchards. This study assessed, under laboratory conditions, the toxicity and duration of the harmful effects of five insecticides, the three pyrethroids deltamethrin, esfenvalerate and lambda-cyhalothrin, and the two neonicotinoids imidacloprid and thiamethoxam on I. zuluagai. Furthermore, we estimated the life-table parameters of the predator. Our results showed that deltamethrin and lambda-cyhalothrin caused higher mortality of larvae and adults than imidacloprid and thiamethoxam. In contrast, esfenvalerate provided larval mortality similar to imidacloprid and thiamethoxam, but it did not cause significant adult mortality of the predator. Mites that developed on pyrethroid residues showed lower survival of the immature stages, fecundity, and longevity compared to neonicotinoid residues and the control treatment. The estimated life-table parameters indicated that deltamethrin, lambda-cyhalothrin and esfenvalerate caused greater reduction in R o and r of I. zuluagai compared with imidacloprid and thiamethoxam, which were similar to the control treatment. Besides the impacts on biological and population parameters, the duration of the harmful activity of pyrethroid insecticides was longer than the neonicotinoids. Therefore, the use of pyrethroid insecticides to control pest insects may involve serious implications for integrated pest-management programs that aim to exploit the biological control by I. zuluagai in citrus orchards.

  8. An amino acid substitution (L925V) associated with resistance to pyrethroids in Varroa destructor.

    Science.gov (United States)

    González-Cabrera, Joel; Davies, T G Emyr; Field, Linda M; Kennedy, Peter J; Williamson, Martin S

    2013-01-01

    The Varroa mite, Varroa destructor, is an important pest of honeybees and has played a prominent role in the decline in bee colony numbers over recent years. Although pyrethroids such as tau-fluvalinate and flumethrin can be highly effective in removing the mites from hives, their intensive use has led to many reports of resistance. To investigate the mechanism of resistance in UK Varroa samples, the transmembrane domain regions of the V. destructor voltage-gated sodium channel (the main target site for pyrethroids) were PCR amplified and sequenced from pyrethroid treated/untreated mites collected at several locations in Central/Southern England. A novel amino acid substitution, L925V, was identified that maps to a known hot spot for resistance within the domain IIS5 helix of the channel protein; a region that has also been proposed to form part of the pyrethroid binding site. Using a high throughput diagnostic assay capable of detecting the mutation in individual mites, the L925V substitution was found to correlate well with resistance, being present in all mites that had survived tau-fluvalinate treatment but in only 8 % of control, untreated samples. The potential for using this assay to detect and manage resistance in Varroa-infected hives is discussed.

  9. Contact Bioassays with Phenoxybenzyl and Tetrafluorobenzyl Pyrethroids against Target-Site and Metabolic Resistant Mosquitoes.

    Directory of Open Access Journals (Sweden)

    Sebastian Horstmann

    Full Text Available Mosquito strains that exhibit increased tolerance to the chemical class of compounds with a sodium channel modulator mode of action (pyrethroids and pyrethrins are typically described as "pyrethroid resistant". Resistance to pyrethroids is an increasingly important challenge in the control of mosquito-borne diseases, such as malaria or dengue, because one of the main interventions (the distribution of large numbers of long-lasting insecticide-treated bed nets currently relies entirely on long-lasting pyrethroids. Increasing tolerance of target insects against this class of insecticides lowers their impact in vector control. The current study suggests that the level of metabolic resistance depends on the structure of the molecule and that structurally different compounds may still be effective because detoxifying enzymes are unable to bind to these uncommon structures.Treated surface contact bioassays were performed on susceptible Aedes aegypti, East African knockdown resistance (kdr Anopheles gambiae (strain RSP-H and metabolically resistant Anopheles funestus (strain FUMOZ-R with different pyrethroids, such as cypermethrin, ß-cyfluthrin, deltamethrin, permethrin and transfluthrin (alone and in combination with the synergist piperonyl butoxide. The nonfluorinated form of transfluthrin was also assessed as a single agent and in combination with piperonyl butoxide.Although the dosages for pyrethroids containing a phenoxybenzyl moiety have exhibited differences in terms of effectiveness among the three tested mosquito species, the structurally different transfluthrin with a polyfluorobenzyl moiety remained active in mosquitoes with upregulated P450 levels. In trials with transfluthrin mixed with piperonyl butoxide, the added synergist exhibited no efficacy-enhancing effect.The results of this study suggest that transfluthrin has the potential to control P450-mediated metabolically resistant mosquitoes because the structural formula of

  10. Contact Bioassays with Phenoxybenzyl and Tetrafluorobenzyl Pyrethroids against Target-Site and Metabolic Resistant Mosquitoes.

    Science.gov (United States)

    Horstmann, Sebastian; Sonneck, Rainer

    2016-01-01

    Mosquito strains that exhibit increased tolerance to the chemical class of compounds with a sodium channel modulator mode of action (pyrethroids and pyrethrins) are typically described as "pyrethroid resistant". Resistance to pyrethroids is an increasingly important challenge in the control of mosquito-borne diseases, such as malaria or dengue, because one of the main interventions (the distribution of large numbers of long-lasting insecticide-treated bed nets) currently relies entirely on long-lasting pyrethroids. Increasing tolerance of target insects against this class of insecticides lowers their impact in vector control. The current study suggests that the level of metabolic resistance depends on the structure of the molecule and that structurally different compounds may still be effective because detoxifying enzymes are unable to bind to these uncommon structures. Treated surface contact bioassays were performed on susceptible Aedes aegypti, East African knockdown resistance (kdr) Anopheles gambiae (strain RSP-H) and metabolically resistant Anopheles funestus (strain FUMOZ-R) with different pyrethroids, such as cypermethrin, ß-cyfluthrin, deltamethrin, permethrin and transfluthrin (alone and in combination with the synergist piperonyl butoxide). The nonfluorinated form of transfluthrin was also assessed as a single agent and in combination with piperonyl butoxide. Although the dosages for pyrethroids containing a phenoxybenzyl moiety have exhibited differences in terms of effectiveness among the three tested mosquito species, the structurally different transfluthrin with a polyfluorobenzyl moiety remained active in mosquitoes with upregulated P450 levels. In trials with transfluthrin mixed with piperonyl butoxide, the added synergist exhibited no efficacy-enhancing effect. The results of this study suggest that transfluthrin has the potential to control P450-mediated metabolically resistant mosquitoes because the structural formula of transfluthrin differs

  11. Identification and characterization of a novel thermostable pyrethroid-hydrolyzing enzyme isolated through metagenomic approach

    Directory of Open Access Journals (Sweden)

    Fan Xinjiong

    2012-03-01

    Full Text Available Abstract Background Pyrethroid pesticides are broad-spectrum pest control agents in agricultural production. Both agricultural and residential usage is continuing to grow, leading to the development of insecticide resistance in the pest and toxic effects on a number of nontarget organisms. Thus, it is necessary to hunt suitable enzymes including hydrolases for degrading pesticide residues, which is an efficient "green" solution to biodegrade polluting chemicals. Although many pyrethroid esterases have consistently been purified and characterized from various resources including metagenomes and organisms, the thermostable pyrethroid esterases have not been reported up to the present. Results In this study, we identified a novel pyrethroid-hydrolyzing enzyme Sys410 belonging to familyV esterases/lipases with activity-based functional screening from Turban Basin metagenomic library. Sys410 contained 280 amino acids with a predicted molecular mass (Mr of 30.8 kDa and was overexpressed in Escherichia coli BL21 (DE3 in soluble form. The optimum pH and temperature of the recombinant Sys410 were 6.5 and 55°C, respectively. The enzyme was stable in the pH range of 4.5-8.5 and at temperatures below 50°C. The activity of Sys410 decreased a little when stored at 4°C for 10 weeks, and the residual activity reached 94.1%. Even after incubation at 25°C for 10 weeks, it kept 68.3% of its activity. The recombinant Sys410 could hydrolyze a wide range of ρ-nitrophenyl esters, but its best substrate is ρ-nitrophenyl acetate with the highest activity (772.9 U/mg. The enzyme efficiently degraded cyhalothrin, cypermethrin, sumicidin, and deltamethrin under assay conditions of 37°C for 15 min, with exceeding 95% hydrolysis rate. Conclusion This is the first report to construct metagenomic libraries from Turban Basin to obtain the thermostable pyrethroid-hydrolyzing enzyme. The recombinant Sys410 with broad substrate specificities and high activity was the most

  12. Exposure to pyrethroids insecticides and serum levels of thyroid-related measures in pregnant women

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jie; Hisada, Aya [Department of Environmental Studies, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563 (Japan); Yoshinaga, Jun, E-mail: junyosh@k.u-tokyo.ac.jp [Department of Environmental Studies, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563 (Japan); Shiraishi, Hiroaki [National Institute for Environmental Studies, Onogawa 16-2, Tsukuba, Ibaraki 305-8563 (Japan); Shimodaira, Kazuhisa; Okai, Takashi [Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555 (Japan); Noda, Yumiko; Shirakawa, Miyako; Kato, Nobumasa [Department of Psychiatry and Neurology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555 (Japan)

    2013-11-15

    Possible association between environmental exposure to pyrethroid insecticides and serum thyroid-related measures was explored in 231 pregnant women of 10–12 gestational weeks recruited at a university hospital in Tokyo during 2009–2011. Serum levels of free thyroxine (fT4), thyroid stimulating hormone (TSH) and thyroid biding globulin (TBG) and urinary pyrethroid insecticide metabolite (3-phenoxybenzoic acid, 3-PBA) were measured. Obstetrical information was obtained from medical records and dietary and lifestyle information was collected by self-administered questionnaire. Geometric mean concentration of creatinine-adjusted urinary 3-PBA was 0.363 (geometric standard deviation: 3.06) μg/g cre, which was consistent with the previously reported levels for non-exposed Japanese adult females. The range of serum fT4, TSH and TBG level was 0.83–3.41 ng/dL, 0.01–27.4 μIU/mL and 16.4–54.4 μg/mL, respectively. Multiple regression analysis was carried out by using either one of serum levels of thyroid-related measures as a dependent variable and urinary 3-PBA as well as other potential covariates (age, pre-pregnancy BMI, parity, urinary iodine, smoking and drinking status) as independent variables: 3-PBA was not found as a significant predictor of serum level of thyroid-related measures. Lack of association may be due to lower pyrethroid insecticide exposure level of the present subjects. Taking the ability of pyrethroid insecticides and their metabolite to bind to nuclear thyroid hormone (TH) receptor, as well as their ability of placental transfer, into consideration, it is warranted to investigate if pyrethroid pesticides do not have any effect on TH actions in fetus brain even though maternal circulating TH level is not affected. -- Highlights: • Pyrethroid exposure and thyroid hormone status was examined in pregnant women. • Urinary 3-phenoxybenzoic acid was used as a biomarker of exposure. • Iodine nutrition, age and other covariates were included

  13. Simultaneous determination of pyrethroids and pyrethrins by dispersive liquid-liquid microextraction and liquid chromatography triple quadrupole mass spectrometry in environmental samples.

    Science.gov (United States)

    Ccanccapa-Cartagena, Alexander; Masiá, Ana; Picó, Yolanda

    2017-08-01

    A simple and environmentally friendly dispersive liquid-liquid microextraction (DLLME) method coupled with electrospray ionization liquid chromatography triple quadrupole mass spectrometry (LC-QqQ-MS/MS) was developed for the simultaneous determination of 17 synthetic and natural pyrethroids. A comparison of solid-phase extraction (SPE) versus DLLME for water samples and only "dilute and shoot" versus the additional extract cleanup by DLLME for sediment samples is reported. Chloroform was the extracting solvent in the DLLME technique for both water and sediment samples. Ultrasonic energy was applied to fully extract the analytes into fine droplets, providing high recoveries in short times. Method detection limits (MDLs) ranged from 0.12 to 0.62 ng L -1 and recoveries from 70 to 119% with RSD values 2-15% (n = 5) for water samples. In sediment samples, MDLs ranged from 0.50 to 2.50 ng g -1 and recoveries from 71 to 112% with RSDs 2-16% (n = 5). The proposed method showed a good linearity within the range of 10-500 ng mL -1 , with coefficients of determination (R 2 ) higher than 0.99. Matrix effects were observed for most compounds in water and sediment (ME% Albufera wetland and Turia River. Acrinathrin (48 ng g -1 ) and etofenprox (16 ng g -1 ) were detected in sediment samples. Graphical abstract Pyrethrins and pyrethroid determination in water and sediments by DLLME and LC-MS/MS.

  14. Association of pyrethroids exposure with onset of puberty in Chinese girls.

    Science.gov (United States)

    Ye, Xiaoqing; Pan, Wuye; Zhao, Yuehao; Zhao, Shilin; Zhu, Yimin; Liu, Weiping; Liu, Jing

    2017-08-01

    Pyrethroids, a class of ubiquitous insecticides, have been considered as endocrine-disrupting chemicals (EDCs). Female animal studies suggested that early-life pyrethroids exposure might delay puberty onset. However, it remains unclear whether this association applies to human populations. A total of 305 girls at the ages of 9-15 years old were recruited in Hangzhou, China in this study. The concentration of the common metabolite of pyrethroids, 3-phenoxybenzoic acid (3-PBA), was analyzed in urine samples to reflect the exposure level of pyrethroids. The associations of 3-PBA with pubertal stages were evaluated using a multinomial logistic regression model. The geometric mean level of 3-PBA was 1.11 μg/L (1.42 μg/g for creatinine-adjusted concentration). There was a significant 45% reduction in odds of being in breast stage 3 (B3) per one-unit increase in the log-transformed 3-PBA levels [OR = 0.55 (95%CI: 0.31-0.98), p = 0.042]. A similar negative association was found between urinary 3-PBA levels with later onset by pubic hair stage 2 (P2) [OR = 0.56 (95%CI: 0.36-0.90), p = 0.015]. Similar negative association was also observed between urinary 3-PBA levels and pubertal onset indicated by menarche [OR = 0.51 (95%CI: 0.28-0.93), p = 0.029]. For the first time to our knowledge, this work reveals that pyrethroids exposure may increase the risk of delayed pubertal onset in girls. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Disposable diaper to collect urine samples from young children for pyrethroid pesticide studies.

    Science.gov (United States)

    Hu, Ye; Beach, James; Raymer, James; Gardner, Micheal

    2004-09-01

    Disposable diapers are widely used in the US and many other areas in the world; therefore, they are ideal media for urine collection for measurement of young children's exposure to pesticides. However, disposable diapers normally contain polyacrylate polymers that make the extraction and analysis of urine very difficult. The objectives of this paper were to evaluate whether disposable diapers that contain polyacrylate granules can be extracted using salt solutions, and whether they can be used for the collection and quantitative measurements of selected urinary pyrethroid pesticide metabolites and creatinine. The storage stability of the metabolites and creatinine in a wet diaper at body temperature and at refrigeration temperature was also evaluated. Salt solutions including calcium chloride dihydrate, magnesium sulfate, ammonium acetate, and sodium chloride solutions were tested for efficiency of polymer shrinkage. Pyrethroid metabolites 3-(2,2-dichlorovinyl)-2,2-dimethyl-(1-cyclopropane) carboxylic acid (DCCA), 3-(2,2-dibromovinyl)-2,2,dimethyl-(1-cyclopropane) carboxylic acid (DBCA) and 3-phenoxybenzoic acid (3-PBA) were analyzed using LC/MS/MS and evaluated for recoveries in the urine released from the diapers. The study found calcium chloride dihydate to be satisfactory in releasing urine and metabolites from the polymers. The percent recoveries for the three tested pyrethroid metabolites were mostly in the range of 65-130. The percent recoveries for creatinine were in the range of 71-133. The detection limit for each of the three metabolites was 0.1 microg/l. The pyrethroid metabolites and creatinine were stable on the diaper for at least 72 h. We concluded from this study that calcium chloride dihydrate can successfully release urine and metabolites from polyacrylate-containing diapers, and the method is promising for studies of pyrethroid metabolites.

  16. Impact of environment on mosquito response to pyrethroid insecticides: facts, evidences and prospects.

    Science.gov (United States)

    Nkya, Theresia Estomih; Akhouayri, Idir; Kisinza, William; David, Jean-Philippe

    2013-04-01

    By transmitting major human diseases such as malaria, dengue fever and filariasis, mosquito species represent a serious threat worldwide in terms of public health, and pose a significant economic burden for the African continent and developing tropical regions. Most vector control programmes aiming at controlling life-threatening mosquitoes rely on the use of chemical insecticides, mainly belonging to the pyrethroid class. However, resistance of mosquito populations to pyrethroids is increasing at a dramatic rate, threatening the efficacy of control programmes throughout insecticide-treated areas, where mosquito-borne diseases are still prevalent. In the absence of new insecticides and efficient alternative vector control methods, resistance management strategies are therefore critical, but these require a deep understanding of adaptive mechanisms underlying resistance. Although insecticide resistance mechanisms are intensively studied in mosquitoes, such adaptation is often considered as the unique result of the selection pressure caused by insecticides used for vector control. Indeed, additional environmental parameters, such as insecticides/pesticides usage in agriculture, the presence of anthropogenic or natural xenobiotics, and biotic interactions between vectors and other organisms, may affect both the overall mosquito responses to pyrethroids and the selection of resistance mechanisms. In this context, the present work aims at updating current knowledge on pyrethroid resistance mechanisms in mosquitoes and compiling available data, often from different research fields, on the impact of the environment on mosquito response to pyrethroids. Key environmental factors, such as the presence of urban or agricultural pollutants and biotic interactions between mosquitoes and their microbiome are discussed, and research perspectives to fill in knowledge gaps are suggested. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. A sodium channel mutation identified in Aedes aegypti selectively reduces cockroach sodium channel sensitivity to type I, but not type II pyrethroids

    Science.gov (United States)

    Hu, Zhaonong; Du, Yuzhe; Nomura, Yoshiko; Dong, Ke

    2010-01-01

    Voltage-gated sodium channels are the primary target of pyrethroid insecticides. Numerous point mutations in sodium channel genes have been identified in pyrethroid-resistant insect species, and many have been confirmed to reduce or abolish sensitivity of channels expressed in Xenopus oocytes to pyrethroids. Recently, several novel mutations were reported in sodium channel genes of pyrethroid-resistant Aedes mosquito populations. One of the mutations is a phenylalanine (F) to cysteine (C) change in segment 6 of domain III (IIIS6) of the Aedes mosquito sodium channel. Curiously, a previous study showed that alanine substitution of this F did not alter the action of deltamethrin, a type II pyrethroid, on a cockroach sodium channel. In this study, we changed this F to C in a pyrethroid-sensitive cockroach sodium channel and examined mutant channel sensitivity to permethrin as well as five other type I or type II pyrethroids in Xenopus oocytes. Interestingly, the F to C mutation drastically reduced channel sensitivity to three type I pyrethroids, permethrin, NRDC 157 (a deltamethrin analogue lacking the α-cyano group) and bioresemthrin, but not to three type II pyrethroids, cypermethrin, deltamethrin and cyhalothrin. These results confirm the involvement of the F to C mutation in permethrin resistance, and raise the possibility that rotation of type I and type II pyrethroids might be considered in the control of insect pest populations where this particular mutation is present. PMID:20869441

  18. Environmentally relevant mixtures in cumulative assessments: an acute study of toxicokinetics and effects on motor activity in rats exposed to a mixture of pyrethroids.

    Science.gov (United States)

    Starr, James M; Scollon, Edward J; Hughes, Michael F; Ross, David G; Graham, Stephen E; Crofton, Kevin M; Wolansky, Marcelo J; Devito, Michael J; Tornero-Velez, Rogelio

    2012-12-01

    Due to extensive use, human exposure to multiple pyrethroid insecticides occurs frequently. Studies of pyrethroid neurotoxicity suggest a common mode of toxicity and that pyrethroids should be considered cumulatively to model risk. The objective of this work was to use a pyrethroid mixture that reflects human exposure to common pyrethroids to develop comparative toxicokinetic profiles in rats, and then model the relationship between brain concentration and motor activity. Data from a national survey of child care centers were used to make a mixture reflecting proportions of the most prevalent pyrethroids: permethrin, cypermethrin, β-cyfluthrin, deltamethrin, and esfenvalerate. The mixture was administered orally at one of two concentrations (11.2 and 27.4 mg/kg) to adult male rats. At intervals from 1 to 24h, motor activity was assessed and the animals were sacrificed. Pyrethroid concentrations were measured in the blood, liver, fat, and brain. After controlling for dose, there were no differences in any tissue concentrations, except blood at the initial time point. Elimination half-lives for all pyrethroids in all tissues were pyrethroids (when cis- and trans-permethrin were pooled) at the initial time point were proportional to their relative doses. Decreases in motor activity indicated dose additivity, and the relationship between pyrethroid brain concentration and motor activity was described by a four-parameter sigmoidal E(max) model. This study links environmental data with toxicokinetic and neurobehavioral assays to support cumulative risk assessments of pyrethroid pesticides. The results support the additive model of pyrethroid effect on motor activity and suggest that variation in the neurotoxicity of individual pyrethroids is related to toxicodynamic rather than toxicokinetic differences.

  19. The sublethal affects of pyrethroid exposure on female mosquito behavior and sand fly behavior in the presence of spatial repellents.

    Science.gov (United States)

    Adult mosquito control consists of barrier treatments and areal spraying often using pyrethroids, however not all host seeking insects contacting insecticides are killed. Sublethal exposure to neurotoxic compounds can negatively affect sensory organs reducing their efficiency for locating hosts. Fe...

  20. Use of an allele-specific polymerase chain reaction assay to genotype pyrethroid resistant strains of Boophilus microplus (Acari: Ixodidae).

    Science.gov (United States)

    Guerrero, F D; Davey, R B; Miller, R J

    2001-01-01

    A polymerase chain reaction-based assay was developed to detect the presence of a pyrethroid resistance-associated amino acid substitution in Boophilus microplus (Canestrini). The assay uses a simple method for the extraction of genomic DNA from individual larvae and genotypes individuals for the presence of a Phe-->Ile amino acid substitution in the S6 transmembrane segment of domain III of the para-like sodium channel, clearly distinguishing heterozygotes from homozygotes. High frequencies for this amino acid substitution were found in the Corrales and San Felipe strains, which have target site insensitivity mechanisms for pyrethroid resistance. The Caporal resistant strain contained lower yet substantial numbers of amino acid-substituted alleles. Low amino acid substitution frequencies were found in the susceptible reference Gonzales strain and the Coatzacoalcos strain, which has metabolic esterase-mediated pyrethroid resistance. The amino acid substitution was not found in six other strains that were susceptible to pyrethroids.

  1. Concentrations of the urinary pyrethroid metabolite 3-phenoxybenzoic acid in farm worker families in the MICASA study

    International Nuclear Information System (INIS)

    Trunnelle, Kelly J.; Bennett, Deborah H.; Ahn, Ki Chang; Schenker, Marc B.; Tancredi, Daniel J.; Gee, Shirley J.; Stoecklin-Marois, Maria T.; Hammock, Bruce D.

    2014-01-01

    Indoor pesticide exposure is a growing concern, particularly from pyrethroids, a commonly used class of pesticides. Pyrethroid concentrations may be especially high in homes of immigrant farm worker families who often live in close proximity to agricultural fields, and are faced with poor housing conditions, causing higher pest infestation and more pesticide use. We investigate exposure of farm worker families to pyrethroids in a study of mothers and children living in Mendota, CA within the population-based Mexican Immigration to California: Agricultural Safety and Acculturation (MICASA) Study. We present pyrethroid exposure based on an ELISA analysis of urinary metabolite 3-phenoxybenzoic acid (3PBA) levels among 105 women and 103 children. The median urinary 3PBA levels (children=2.56 ug/g creatinine, mothers=1.46 ug/g creatinine) were higher than those reported in population based studies for the United States general population, but similar to or lower than studies with known high levels of pyrethroid exposure. A positive association was evident between poor housing conditions and the urinary metabolite levels, showing that poor housing conditions are a contributing factor to the higher levels of 3PBA seen in the urine of these farm worker families. Further research is warranted to fully investigate sources of exposure. - Highlights: • We investigate exposure of farm worker families to pyrethroids. • We present pyrethroid exposure based on an ELISA analysis of urinary 3PBA levels. • 3PBA levels were higher than those reported for the U.S. general population. • Poor housing conditions may be associated with pyrethroid exposure

  2. Concentrations of the urinary pyrethroid metabolite 3-phenoxybenzoic acid in farm worker families in the MICASA study

    Energy Technology Data Exchange (ETDEWEB)

    Trunnelle, Kelly J., E-mail: kjtrunnelle@ucdavis.edu [Department of Environmental Toxicology, University of California, Davis 1 Shields Avenue, Davis, CA 95616 (United States); Bennett, Deborah H. [Department of Public Health Sciences, University of California, Davis, CA 95616 (United States); Ahn, Ki Chang [Department of Entomology and Cancer Center, University of California, Davis 1 Shields Avenue, Davis, CA 95616 (United States); Schenker, Marc B. [Department of Public Health Sciences, University of California, Davis, CA 95616 (United States); Tancredi, Daniel J. [Department of Pediatrics, University of California, Davis School of Medicine, 4610 X Street Sacramento, CA 95817 (United States); Gee, Shirley J. [Department of Entomology and Cancer Center, University of California, Davis 1 Shields Avenue, Davis, CA 95616 (United States); Stoecklin-Marois, Maria T. [Department of Public Health Sciences, University of California, Davis, CA 95616 (United States); Hammock, Bruce D. [Department of Entomology and Cancer Center, University of California, Davis 1 Shields Avenue, Davis, CA 95616 (United States)

    2014-05-01

    Indoor pesticide exposure is a growing concern, particularly from pyrethroids, a commonly used class of pesticides. Pyrethroid concentrations may be especially high in homes of immigrant farm worker families who often live in close proximity to agricultural fields, and are faced with poor housing conditions, causing higher pest infestation and more pesticide use. We investigate exposure of farm worker families to pyrethroids in a study of mothers and children living in Mendota, CA within the population-based Mexican Immigration to California: Agricultural Safety and Acculturation (MICASA) Study. We present pyrethroid exposure based on an ELISA analysis of urinary metabolite 3-phenoxybenzoic acid (3PBA) levels among 105 women and 103 children. The median urinary 3PBA levels (children=2.56 ug/g creatinine, mothers=1.46 ug/g creatinine) were higher than those reported in population based studies for the United States general population, but similar to or lower than studies with known high levels of pyrethroid exposure. A positive association was evident between poor housing conditions and the urinary metabolite levels, showing that poor housing conditions are a contributing factor to the higher levels of 3PBA seen in the urine of these farm worker families. Further research is warranted to fully investigate sources of exposure. - Highlights: • We investigate exposure of farm worker families to pyrethroids. • We present pyrethroid exposure based on an ELISA analysis of urinary 3PBA levels. • 3PBA levels were higher than those reported for the U.S. general population. • Poor housing conditions may be associated with pyrethroid exposure.

  3. Pyrethroids cypermethrin, deltamethrin and fenvalerate have different effects on in vitro maturation of pig oocytes at different stages of growth.

    Science.gov (United States)

    Petr, J; Chmelíková, E; Zalmanová, T; Tůmová, L; Kheilová, K; Kučerová-Chrpová, V; Jílek, F

    2013-01-01

    Pesticides can significantly harm reproduction in animals and people. Pyrethroids are often used as insecticides, and their toxicity for mammals is considered to be low. However, cypermethrin, deltamethrin and fenvalerate - as potent specific inhibitors of protein phosphatase calcineurin - can influence the meiosis of mammalian oocytes. The objective of this study was to evaluate the effects of these pyrethroids on the in vitro maturation of pig oocytes at different levels of meiotic competence. Under the tested concentrations, cypermethrin, deltamethrin and fenvalerate neither had a significant effect on the viability of oocytes nor did they induce significant degeneration of oocytes. However, these pyrethroids significantly affected meiotic maturation. The effects depended on the stage of meiotic competence of the oocytes. Maturation of growing pig oocytes with partial meiotic competence was induced. On the other hand, in fully grown pig oocytes with full meiotic competence, maturation in vitro was delayed. The specificity of these effects was further supported by the same effect of non-pyrethroidal inhibitors of calcineurin - cyclosporin A or hymenistatin I - on the maturation of oocytes with different levels of meiotic competence. However, pyrethroids, which do not inhibit calcineurin - allethrin or permethrin - had no effect on pig oocyte maturation. We demonstrated a significant effect of pyrethroids on the maturation of mammalian oocytes under in vitro conditions. This indicates that exposure to these substances could affect the fertility of people or animals.

  4. Identification of hotspots for potential pyrethroid runoff: a GIS modeling study in San Joaquin River Watershed of California, USA

    Science.gov (United States)

    Zhang, Xuyang; Zhang, Minghua; Liu, Xingmei

    2008-09-01

    This paper attempts to identify the high-risk areas for potential runoff of pyrethroid pesticides in the San Joaquin River Watershed. Pyrethroid pesticides have been detected in water and fluvial sediments in this watershed, creating concerns about potential negative impacts on water quality. However, little documentation exists regarding the distributions or the extent of the adverse effects caused by the use of pyrethroids. This study developed a geographic information systems (GIS) model to identify areas with high potential for pyrethroid runoff during the rainy season. The model was then validated using field-monitoring data. Nine factors were identified for the runoff risk assessment: amount of active ingredient used, soil erodibility factor, hydrologic group, surface layer depth, seasonal rainfall, seasonal number of rainy days, seasonal number of storm events, stream density, and land cover. The results indicated that high pyrethroid runoff risks were associated with basins such as the Stanislaus River Sub-basin, Newman Gustine Sub-basin and South Merced Sub-basin. This study demonstrated that the GIS model is capable of predicting high-risk areas of pyrethroid runoff at sub-basin scale. The model can be used to prioritize sites for water quality monitoring and guide implementations of best management practices.

  5. Pyrethroid Resistance Reduces the Efficacy of Space Sprays for Dengue Control on the Island of Martinique (Caribbean)

    Science.gov (United States)

    Marcombe, Sébastien; Darriet, Frédéric; Tolosa, Michel; Agnew, Philip; Duchon, Stéphane; Etienne, Manuel; Yp Tcha, Marie Michèle; Chandre, Fabrice; Corbel, Vincent; Yébakima, André

    2011-01-01

    Background Dengue fever is reemerging on the island of Martinique and is a serious threat for the human population. During dengue epidemics, adult Aedes aegypti control with pyrethroid space sprays is implemented in order to rapidly reduce transmission. Unfortunately, vector control programs are facing operational challenges with the emergence of pyrethroid resistant Ae. aegypti populations. Methodology/Principal Findings To assess the impact of pyrethroid resistance on the efficacy of treatments, applications of deltamethrin and natural pyrethrins were performed with vehicle-mounted thermal foggers in 9 localities of Martinique, where Ae. aegypti populations are strongly resistant to pyrethroids. Efficacy was assessed by monitoring mortality rates of naturally resistant and laboratory susceptible mosquitoes placed in sentinel cages. Before, during and after spraying, larval and adult densities were estimated. Results showed high mortality rates of susceptible sentinel mosquitoes treated with deltamethrin while resistant mosquitoes exhibited very low mortality. There was no reduction of either larval or adult Ae. aegypti population densities after treatments. Conclusions/Significance This is the first documented evidence that pyrethroid resistance impedes dengue vector control using pyrethroid-based treatments. These results emphasize the need for alternative tools and strategies for dengue control programs. PMID:21713017

  6. [From synthetic biology to synthetic humankind].

    Science.gov (United States)

    Nouvel, Pascal

    2015-01-01

    In this paper, we propose an historical survey of the expression "synthetic biology" in order to identify its main philosophical components. The result of the analysis is then used to investigate the meaning of the notion of "synthetic man". It is shown that both notions share a common philosophical background that can be summed up by the short but meaningful assertion: "biology is technology". The analysis allows us to distinguish two notions that are often confused in transhumanist literature: the notion of synthetic man and the notion of renewed man. The consequences of this crucial distinction are discussed. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  7. Synthetic Cathinones ("Bath Salts")

    Science.gov (United States)

    ... cathinones? Behavioral therapy can be used to treat addiction to synthetic cathinones. Examples include: cognitive-behavioral therapy contingency management, or motivational incentives—providing rewards to ...

  8. Alanine to valine substitutions in the pore helix IIIP1 and linker-helix IIIL45 confer cockroach sodium channel resistance to DDT and pyrethroids.

    Science.gov (United States)

    Chen, Mengli; Du, Yuzhe; Nomura, Yoshiko; Zhu, Guonian; Zhorov, Boris S; Dong, Ke

    2017-05-01

    Pyrethroid insecticides exert toxic effects by prolonging the opening of voltage-gated sodium channels. More than 20 sodium channel mutations from arthropod pests and disease vectors have been confirmed to confer pyrethroid resistance. These mutations have been valuable in elucidating the molecular interaction between pyrethroids and sodium channels, including identification of two pyrethroid receptor sites. Previously, two alanine to valine substitutions, one in the pore helix IIIP1 and the other in the linker-helix connecting S4 and S5 in domain III (IIIL45), were found in Drosophila melanogaster mutants that are resistant to DDT and deltamethrin (a type II pyrethroid with an α-cyano group at the phenylbenzyl alcohol position, which is lacking in type I pyrethroids), but their role in target-site-mediated insecticide resistance has not been functionally confirmed. In this study, we functionally examined the two mutations in cockroach sodium channels expressed in Xenopus laevis oocytes. Both mutations caused depolarizing shifts in the voltage dependence of activation, conferred DDT resistance and also resistance to two Type I pyrethroids by almost abolishing the tail currents induced by Type I pyrethroids. In contrast, neither mutation reduced the amplitude of tail currents induced by the Type II pyrethroids, deltamethrin or cypermethrin. However, both mutations accelerated the decay of Type II pyrethroid-induced tail currents, which normally decay extremely slowly. These results provided new insight into the molecular basis of different actions of Type I and Type II pyrethroids on sodium channels. Computer modeling predicts that both mutations may allosterically affect pyrethroid binding. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Runoff of pyrethroid insecticides from concrete surfaces following simulated and natural rainfalls.

    Science.gov (United States)

    Jiang, Weiying; Haver, Darren; Rust, Michael; Gan, Jay

    2012-03-01

    Intensive residential use of insecticides has resulted in their ubiquitous presence as contaminants in urban surface streams. For pest eradication, urban hard surfaces such as concrete are often directly treated with pesticides, and wind/water can also carry pesticides onto hard surfaces from surrounding areas. This study expanded on previous bench-scale studies by considering pesticide runoff caused by irrigation under dry weather conditions and rain during the wet season, and evaluated the effects of pesticide residence time on concrete, single versus recurring precipitations, precipitation intensity, and concrete surface conditions, on pesticide transferability to runoff water. Runoff from concrete 1 d after pesticide treatment contained high levels of bifenthrin (82 μg/L) and permethrin (5143 μg/L for cis and 5518 μg/L for trans), indicating the importance of preventing water contact on concrete after pesticide treatments. Although the runoff transferability quickly decreased as the pesticide residence time on concrete increased, detectable residues were still found in runoff water after 3 months (89 d) exposure to hot and dry summer conditions. ANOVA analysis showed that precipitation intensities and concrete surface conditions (i.e., acid wash, silicone seal, stamping, and addition of microsilica) did not significantly affect the pesticide transferability to runoff. For concrete slabs subjected to natural rainfalls during the winter wet season, pesticide levels in the runoff decreased as the time interval between pesticide application and the rain event increased. However, bifenthrin and permethrin were still detected at 0.15-0.17 and 0.75-1.15 μg/L in the rain runoff after 7 months (221 d) from the initial treatment. In addition, pesticide concentrations showed no decrease between the two rainfall events, suggesting that concrete surfaces contaminated by pesticides may act as a reservoir for pesticide residues, leading to sustained urban runoff

  10. Characterisation of adult green lacewing (Chrysoperla carnea) digestive physiology: impact of a cysteine protease inhibitor and a synthetic pyrethroid.

    Science.gov (United States)

    Mulligan, Evan A; Ferry, Natalie; Jouanin, Lise; Romeis, Jörg; Gatehouse, Angharad M R

    2010-03-01

    In spite of concern regarding potential non-target effects of GM crops, few studies have compared GM pest control with conventional methods. The impacts of cypermethrin and oilseed rape expressing oryzacystatin-1 (OC-1) were compared in this study on the predator Chrysoperla carnea (Stephens). Adults fed purified rOC-1 showed a subtle shift in digestive protease profile, with an increasing reliance on serine proteases (chymotrypsin), increase in aspartic proteases and a slight reduction in elastase activity. Although there were no effects on mortality, onset of oviposition was delayed; however, once egg production commenced, egg laying and hatching success rates were comparable with those of controls. Oryzacystatin-1 expressed in pollen showed no detrimental effects. Cypermethrin had no effect on mortality owing to high levels of non-specific esterase activity resulting in partial breakdown of the insecticide. In spite of this, there was a significant delay in onset of oviposition and a significant reduction in egg production and viability. This study demonstrates the potential for pest management to impact on predators, but importantly it highlights the ability of the predator to detoxify/respond to treatments with different modes of action. In this case, exposure to an insecticide carried a greater fitness cost than exposure to a protease inhibitor expressed in transgenic crops.

  11. Monitoring of Total Type II Pyrethroid Pesticides in Citrus Oils and Water by Converting to a Common Product 3-Phenoxybenzoic Acid

    Science.gov (United States)

    McCoy, Mark R.; Yang, Zheng; Fu, Xun; Ahn, Ki Chang; Gee, Shirley J.; Bom, David C.; Zhong, Ping; Chang, Dan; Hammock, Bruce D.

    2012-01-01

    Pyrethroids are a class of insecticides that are becoming increasingly popular in agricultural and home use applications. Sensitive assays for pyrethroid insecticides in complex matrices are difficult both with instrumental and immunochemical methods. Environmental analysis of the pyrethroids by immunoassay requires either knowing which pyrethroids contaminate the source or the use of non-specific antibodies with cross reactivities to a class of compounds. We describe an alternative method that converts the type-II-pyrethroids to a common chemical product, 3-phenoxybenzoic acid (3-PBA), prior to analysis. This method is much more sensitive than detecting the parent compound, and it is much easier to detect a single compound rather than an entire class of compounds. This is useful in screening for pyrethroids as a class or in situations where a single type of pyrethroid is used. We demonstrated this technique in both citrus oils and environmental water samples with conversion rates of the pyrethroid to 3-PBA that range from 45%-75% and methods that require no extraction steps for either the immunoassay or LC-MS/MS techniques. Limits of detection for this technique applied to orange oil are 5 nM, 2 μM, and 0.8 μM when detected by LC-MS/MS, GC-MS, and immunoassay respectively. The limit of detection for pyrethroids in water when detected by immunoassay was 2 nM. PMID:22486225

  12. Children’s Exposures to Pyrethroid Insecticides at Home: A Review of Data Collected in Published Exposure Measurement Studies Conducted in the United States

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    Marsha K. Morgan

    2012-08-01

    Full Text Available Pyrethroid insecticides are frequently used to control insects in residential and agriculture settings in the United States and worldwide. As a result, children can be potentially exposed to pyrethroid residues in food and at home. This review summarizes data reported in 15 published articles from observational exposure measurement studies conducted from 1999 to present that examined children’s (5 months to 17 years of age exposures to pyrethroids in media including floor wipes, floor dust, food, air, and/or urine collected at homes in the United States. At least seven different pyrethroids were detected in wipe, dust, solid food, and indoor air samples. Permethrin was the most frequently detected (>50% pyrethroid in these media, followed by cypermethrin (wipes, dust, and food. 3-phenoxybenzoic acid (3-PBA, a urinary metabolite of several pyrethroids, was the most frequently (≥67% detected pyrethroid biomarker. Results across studies indicate that these children were likely exposed to several pyrethroids, but primarily to permethrin and cypermethrin, from several sources including food, dust, and/or on surfaces at residences. Dietary ingestion followed by nondietary ingestion were the dominate exposure routes for these children, except in homes with frequent pesticide applications (dermal followed by dietary ingestion. Urinary 3-PBA concentration data confirm that the majority of the children sampled were exposed to one or more pyrethroids.

  13. Children’s Exposures to Pyrethroid Insecticides at Home: A Review of Data Collected in Published Exposure Measurement Studies Conducted in the United States

    Science.gov (United States)

    Morgan, Marsha K.

    2012-01-01

    Pyrethroid insecticides are frequently used to control insects in residential and agriculture settings in the United States and worldwide. As a result, children can be potentially exposed to pyrethroid residues in food and at home. This review summarizes data reported in 15 published articles from observational exposure measurement studies conducted from 1999 to present that examined children’s (5 months to 17 years of age) exposures to pyrethroids in media including floor wipes, floor dust, food, air, and/or urine collected at homes in the United States. At least seven different pyrethroids were detected in wipe, dust, solid food, and indoor air samples. Permethrin was the most frequently detected (>50%) pyrethroid in these media, followed by cypermethrin (wipes, dust, and food). 3-phenoxybenzoic acid (3-PBA), a urinary metabolite of several pyrethroids, was the most frequently (≥67%) detected pyrethroid biomarker. Results across studies indicate that these children were likely exposed to several pyrethroids, but primarily to permethrin and cypermethrin, from several sources including food, dust, and/or on surfaces at residences. Dietary ingestion followed by nondietary ingestion were the dominate exposure routes for these children, except in homes with frequent pesticide applications (dermal followed by dietary ingestion). Urinary 3-PBA concentration data confirm that the majority of the children sampled were exposed to one or more pyrethroids. PMID:23066409

  14. Quantum synthetic aperture radar

    Science.gov (United States)

    Lanzagorta, Marco; Jitrik, Oliverio; Uhlmann, Jeffrey; Venegas-Andraca, Salvador E.

    2017-05-01

    Synthetic aperture radar (SAR) uses sensor motion to generate finer spatial resolution of a given target area. In this paper we explore the theoretical potential of quantum synthetic aperture quantum radar (QSAR). We provide theoretical analysis and simulation results which suggest that QSAR can provide improved detection performance over classical SAR in the high-noise low-brightness regime.

  15. Designing synthetic biology.

    Science.gov (United States)

    Agapakis, Christina M

    2014-03-21

    Synthetic biology is frequently defined as the application of engineering design principles to biology. Such principles are intended to streamline the practice of biological engineering, to shorten the time required to design, build, and test synthetic gene networks. This streamlining of iterative design cycles can facilitate the future construction of biological systems for a range of applications in the production of fuels, foods, materials, and medicines. The promise of these potential applications as well as the emphasis on design has prompted critical reflection on synthetic biology from design theorists and practicing designers from many fields, who can bring valuable perspectives to the discipline. While interdisciplinary connections between biologists and engineers have built synthetic biology via the science and the technology of biology, interdisciplinary collaboration with artists, designers, and social theorists can provide insight on the connections between technology and society. Such collaborations can open up new avenues and new principles for research and design, as well as shed new light on the challenging context-dependence-both biological and social-that face living technologies at many scales. This review is inspired by the session titled "Design and Synthetic Biology: Connecting People and Technology" at Synthetic Biology 6.0 and covers a range of literature on design practice in synthetic biology and beyond. Critical engagement with how design is used to shape the discipline opens up new possibilities for how we might design the future of synthetic biology.

  16. Level of CYP4G19 Expression Is Associated with Pyrethroid Resistance in Blattella germanica

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    Guang-zhou Guo

    2010-01-01

    Full Text Available German cockroaches have become a large problem in the Shenzhen area because of their pesticide resistance, especially to pyrethroid. A pyrethroid called “Jia Chong Qing” to prevent pests for a long time were found to be resistant to “Jia Chong Qing” with resistance index of 3.88 measured using RT-PCR and immunohistochemistry analysis showed that both CYP4G19 mRNA and CYP4G19 protein expression levels in the wild strain were substantially higher than that of a sensitive strain. dsRNA segments derived from the target gene CYP4G19 were prepared using in vitro transcription and were microinjected into abdomens of the wild strain. Two to eight days after injection, the result showed that CYP4G19 mRNA expressions were significantly reduced in the groups injected with dsRNAs.

  17. Identification and immobilization of a novel cold-adapted esterase, and its potential for bioremediation of pyrethroid-contaminated vegetables.

    Science.gov (United States)

    Fan, Xinjiong; Liang, Weiqu; Li, Yanfang; Li, He; Liu, Xiaolong

    2017-09-11

    Pyrethroids are potentially harmful to living organisms and ecosystems. Thus, concerns have been raised about pyrethroid residues and their persistence in agricultural products. To date, although several pyrethroid-hydrolyzing enzymes have been cloned, very few reports are available on pyrethroid-hydrolyzing enzymes with cold adaptation, high hydrolytic activity and good reusability, indispensable properties in practical bioremediation of pyrethroid-contaminated vegetables. Here, a novel gene (est684) encoding pyrethroid-hydrolyzing esterase was isolated from the Mao-tofu metagenome for the first time. Est684 encoded a protein of 227 amino acids and was expressed in Escherichia coli BL21 (DE3) in soluble form. The optimum temperature was 18 °C. It maintained 46.1% of activity at 0 °C and over 50% of its maximal activity at 4-35 °C. With the goal of enhancing stability and recycling biocatalysts, we used mesoporous silica SBA-15 as a nanometer carrier for the efficient immobilization of Est684 by the absorption method. The best conditions were an esterase-to-silica ratio of 0.96 mg/g (w/w) and an adsorption time of 30 min at 10 °C. Under these conditions, the recovery of enzyme activity was 81.3%. A large improvement in the thermostability of Est684 was achieved. The half-life (T 1/2 ) of the immobilized enzyme at 35 °C was 6 h, 4 times longer than the soluble enzyme. Interestingly, the immobilized Est684 had less loss in enzyme activity up to 12 consecutive cycles, and it retained nearly 54% of its activity after 28 cycles, indicating excellent operational stability. Another noteworthy characteristic was its high catalytic activity. It efficiently hydrolyzed cyhalothrin, cypermethrin, and fenvalreate in pyrethroid-contaminated cucumber within 5 min, reaching over 85% degradation efficiency after four cycles. A novel cold-adapted pyrethroid-hydrolyzing esterase was screened from the Mao-tofu metagenome. This report is the first on immobilizing

  18. Presence of pyrethroid pesticides in water and sediments of Ebro River Delta

    Science.gov (United States)

    Feo, M. L.; Ginebreda, A.; Eljarrat, E.; Barceló, D.

    2010-11-01

    SummaryThe distribution of pyrethroid insecticides of the Ebro River Delta (NE Spain) was assessed by measuring concentrations in surface water and sediment samples. Pyrethroid extraction from water was carried out by ultrasound-assisted emulsification-extraction (UAEE), while the sediment was sonicated and cleaned up using Florisil cartridge. Method detection of limits (MLODs) for the 12 pyrethroids analyzed by gas chromatography-mass spectrometer in negative chemical ionization (GC-NCI-MS) ranged from 0.03 to 35.8 ng L -1 for water and 2.6 to 62.4 pg g -1 for sediment. Recoveries values were in the range of 47-105% for water and 51-105% for sediments, showing satisfactory robustness of the method for analyzing pyrethroids in water and sediment samples. Cypermethrin was detected in 22 water samples collected from Ebro River Delta, while deltamethrin was present only in three water samples at concentrations ranging from 0.73 ng L -1 to 57.2 ng L -1 and 2 ng L -1 to 58.8 ng L -1 for cypermethrin and deltamethrin, respectively. These concentration levels were higher than median lethal concentration (LC50) values found for deltamethrin and lower than LC50 values found for cypermethrin when short time toxic effects are considered. In sediment samples only cypermethrin was detected at concentration levels ranged from 8.27 ng g -1 to 71.9 ng g -1. These levels were higher than its LC50 values. Environmental dynamic behaviour and fate were also evaluated for cypermethrin measuring the sediment/water partition coefficient (ranging from 5.0 to 6.3) and kinetic data (half-life ranging between 13 and 50 days). Results were in good agreement to those reported in literature

  19. Comparison of the toxic effect of pyrethroids on Ixodes ricinus and Dermacentor reticulatus females.

    Science.gov (United States)

    Buczek, Alicja; Bartosik, Katarzyna; Kuczyński, Paweł

    2014-01-01

    Despite the increased rates of infestations with I. ricinus (Ir) and D. reticulatus (Dr) ticks observed over the last decade, no effective control methods have been developed so far. The present study was focused on assessment of the action of pyrethroids on these both tick species. The different doses of four pyrethroids, i.e. deltamethrin - D (K-Othrine), permethrin - P (Copex WP), cypermethrin - C (Kordon 10WP), and alphacypermethrin - AC (Alfasekt 5SC) were tested. The LD₅₀ for each tested compound was also determined for both tick species. Unengorged and engorged (maintained on rabbit skin) tick females were sprayed with 20 ml of 0.01563-0.50% solutions of the tested preparations. The investigations showed that sensitivity of Ir and Dr to the tested pyrethroids, but the effects exerted by the different doses varied between both tick species and between engorged and unengorged females in these species. The strongest toxic effect on unengorged and engorged Ir and Dr females was exerted by D, whereas the effect of AC was weaker. The LD ₅₀ (in µg/1 g b.w.) of D, AC, C, and P for unengorged Ir and Dr females was, respectively, 55.4 and 25.5, 105.2 and 48.5, 225.9 and 197.7, and 553.8 and 380.8. In the case of engorged Ir and Dr females, the LD₅₀ of AC, D, C, and P reached a value of 0.9453 and 0.2310, 1.0428 and 1.3533, 3.489 and 6.5662, and 8.3955 and 7.3940, respectively. The differences between the effects of the tested pyrethroids and their different doses on Ir and Dr highlight the necessity for development of a strategy for control of the tick species in different regions, based on investigations of their sensitivity to chemical compounds.

  20. Unexpected Failures to Control Chagas Disease Vectors With Pyrethroid Spraying in Northern Argentina

    Science.gov (United States)

    Gurevitz, J. M.; Gaspe, M. S.; Enríquez, G. F.; Vassena, C. V.; Alvarado-Otegui, J. A.; Provecho, Y. M.; Mougabure Cueto, G. A; Picollo, M. I.; Kitron, U.; Gürtler, R. E.

    2013-01-01

    Effectiveness of the elimination efforts against Triatoma infestans (Klug) in South America through residual application of pyrethroid insecticides has been highly variable in the Gran Chaco region. We investigated apparent vector control failures after a standard community-wide spraying with deltamethrin SC in a rural area of northeastern Argentina encompassing 353 houses. Insecticide spraying reduced house infestation less than expected: from 49.5% at baseline to 12.3 and 6.7% at 4 and 8 mo postspraying, respectively. Persistent infestations were detected in 28.4% of houses, and numerous colonies with late-stage bugs were recorded after the interventions. Laboratory bioassays showed reduced susceptibility to pyrethroids in the local bug populations. Eleven of 14 bug populations showed reduced mortality in diagnostic dose assays (range, 35 ± 5% to 97 ± 8%) whereas the remainder had 100% mortality. A fully enclosed residual bug population in a large chicken coop survived four pyrethroid sprays, including two double-dose applications, and was finally suppressed with malathion. The estimated resistance ratio of this bug population was 7.17 (range, 4.47–11.50). Our field data combined with laboratory bioassays and a residual foci experiment demonstrate that the initial failure to suppress T. infestans was mainly because of the unexpected occurrence of reduced susceptibility to deltamethrin in an area last treated with pyrethroid insecticides 12 yr earlier. Our results underline the need for close monitoring of the impact of insecticide spraying to provide early warning of possible problems due to enhanced resistance or tolerance and determine appropriate responses. PMID:23270166

  1. Transcription profiling of a recently colonised pyrethroid resistant Anopheles gambiae strain from Ghana

    Directory of Open Access Journals (Sweden)

    Donnelly Martin J

    2007-01-01

    Full Text Available Abstract Background Mosquito resistance to the pyrethroid insecticides used to treat bednets threatens the sustainability of malaria control in sub-Saharan Africa. While the impact of target site insensitivity alleles is being widely discussed the implications of insecticide detoxification – though equally important – remains elusive. The successful development of new tools for malaria intervention and management requires a comprehensive understanding of insecticide resistance, including metabolic resistance mechanisms. Although three enzyme families (cytochrome P450s, glutathione S-transferases and carboxylesterases have been widely associated with insecticide detoxification the role of individual enzymes is largely unknown. Results Here, constitutive expression patterns of genes putatively involved in conferring pyrethroid resistance was investigated in a recently colonised pyrethroid resistant Anopheles gambiae strain from Odumasy, Southern Ghana. RNA from the resistant strain and a standard laboratory susceptible strain, of both sexes was extracted, reverse transcribed and labelled with either Cy3- or Cy5-dye. Labelled cDNA was co-hybridised to the detox chip, a custom-made microarray containing over 230 A. gambiae gene fragments predominantly from enzyme families associated with insecticide resistance. After hybridisation, Cy3- and Cy5-signal intensities were measured and compared gene by gene. In both females and males of the resistant strain the cytochrome P450s CYP6Z2 and CYP6M2 are highly over-expressed along with a member of the superoxide dismutase (SOD gene family. Conclusion These genes differ from those found up-regulated in East African strains of pyrethroid resistant A. gambiae and constitute a novel set of candidate genes implicated in insecticide detoxification. These data suggest that metabolic resistance may have multiple origins in A. gambiae, which has strong implications for the management of resistance.

  2. Pyrethroid susceptibility of malaria vectors in four Districts of western Kenya.

    Science.gov (United States)

    Ochomo, Eric; Bayoh, Nabie M; Kamau, Luna; Atieli, Francis; Vulule, John; Ouma, Collins; Ombok, Maurice; Njagi, Kiambo; Soti, David; Mathenge, Evan; Muthami, Lawrence; Kinyari, Teresa; Subramaniam, Krishanthi; Kleinschmidt, Immo; Donnelly, Martin James; Mbogo, Charles

    2014-07-04

    Increasing pyrethroid resistance in malaria vectors has been reported in western Kenya where long lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are the mainstays of vector control. To ensure the sustainability of insecticide-based malaria vector control, monitoring programs need to be implemented. This study was designed to investigate the extent and distribution of pyrethroid resistance in 4 Districts of western Kenya (Nyando, Rachuonyo, Bondo and Teso). All four Districts have received LLINs while Nyando and Rachuonyo Districts have had IRS campaigns for 3-5 years using pyrethroids. This study is part of a programme aimed at determining the impact of insecticide resistance on malaria epidemiology. Three day old adult mosquitoes from larval samples collected in the field, were used for bioassays using the WHO tube bioassay, and mortality recorded 24 hours post exposure. Resistance level was assigned based on the 2013 WHO guidelines where populations with District with mortality to deltamethrin ranging from 45-100%, while to permethrin the range was 30-100%. Mortality to deltamethrin in Teso District was eco-epidemiological zones.

  3. LABORATORY PROTECTION RATE OF TORN BEDNETS TREATED WITH THREE DOSAGES OF PYRETHROIDE AGAINST ANOPHELES CULICIFACIES

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    G. Babaee

    2007-05-01

    Full Text Available Evaluated under laboratory condition. The objective of the present study was to observe the effect of impregnated torn bednets on the number of bites by An. culicifacies A glass made tunnel test was designed to The effect of torn bednets treated with three dosages of cyfluthrin 5% EW, were induce hungry female mosquitoes to pass through holes cut in the pyrethroid treated nets. A guinea pig used as bait to attract mosquitoes through circular holes in the netting. With untreated netting, 72-87% of laboratory-reared females passed through the holes overnight, 64-92% blood-fed successfully and 0.3/9-4/3% died. When the netting was treated with cyfluthrin at doses of 25, 50 and 100 mg a.i./m2, the entry Index (the proportions that passed through the holes overnight were 43.37%, 42.82% and 24.72%; mortality rates were 66.31%, 81.45% and 95.99%; and the feeding rate were 45%, 27% and 3%. In conclusion it should be stressed that efficacy of pyrethroid impregnated bednets using “Tunnel Tests” showing acceptable protection rate both in lower and higher dosages as well as cause dead in the blood-fed mosquitoes. In addition, the higher dosages of these three dosages pyrethroid provided good levels of protection against An. culicifacies.

  4. Relationship between knockdown resistance, metabolic detoxification and organismal resistance to pyrethroids in Anopheles sinensis.

    Science.gov (United States)

    Zhong, Daibin; Chang, Xuelian; Zhou, Guofa; He, Zhengbo; Fu, Fengyang; Yan, Zhentian; Zhu, Guoding; Xu, Tielong; Bonizzoni, Mariangela; Wang, Mei-Hui; Cui, Liwang; Zheng, Bin; Chen, Bin; Yan, Guiyun

    2013-01-01

    Anopheles sinensis is the most important vector of malaria in Southeast Asia, including China. Currently, the most effective measure to prevent malaria transmission relies on vector control through the use of insecticides, primarily pyrethroids. Extensive use of insecticides poses strong selection pressure on mosquito populations for resistance. Resistance to insecticides can arise due to mutations in the insecticide target site (target site resistance), which in the case of pyrethroids is the para-type sodium channel gene, and/or the catabolism of the insecticide by detoxification enzymes before it reaches its target (metabolic detoxification resistance). In this study, we examined deltamethrin resistance in An. sinensis from China and investigated the relative importance of target site versus metabolic detoxification mechanisms in resistance. A high frequency (>85%) of nonsynonymous mutations in the para gene was found in populations from central China, but not in populations from southern China. Metabolic detoxification as measured by the activity of monooxygenases and glutathione S-transferases (GSTs) was detected in populations from both central and southern China. Monooxygenase activity levels were significantly higher in the resistant than the susceptible mosquitoes, independently of their geographic origin. Stepwise multiple regression analyses in mosquito populations from central China found that both knockdown resistance (kdr) mutations and monooxygenase activity were significantly associated with deltamethrin resistance, with monooxygenase activity playing a stronger role. These results demonstrate the importance of metabolic detoxification in pyrethroid resistance in An. sinensis, and suggest that different mechanisms of resistance could evolve in geographically different populations.

  5. Pyrethroid-sprayed tents for malaria control: an entomological evaluation in Pakistan.

    Science.gov (United States)

    Hewitt, S; Rowland, M; Muhammad, N; Kamal, M; Kemp, E

    1995-10-01

    Field trials were undertaken in the North West Frontier Province of Pakistan to determine the effects of pyrethroid-sprayed tents on feeding success, mortality and biting-rates of wild mosquitoes attracted to bait cows confined within the tents. Under natural conditions, endophagic mosquitoes rested only briefly in untreated tents during the night, followed by complete exodus at dawn. In tents sprayed on the interior surface with permethrin 0.5 mg/m2 or with deltamethrin 0.03 g/m2 the biting rate of Anopheles stephensi was reduced by about 40%; deterrency against culicines and other anophelines was much less. Mortality-rates of bloodfed mosquitoes from the treated tents were 75% An.stephensi, 65% An.subpictus but only 10% of culicines. Outer fly-sheets prolonged the effective life of the treatment; bioassays on the sprayed inner-sheets showed that insecticidal efficacy remained high for over a year, whereas on tents without fly-sheets permethrin residual efficacy declined rapidly 20-40 weeks post-treatment. It is concluded that tent-spraying with fast-acting photostable residual pyrethroid insecticide would probably provide effective protection against malaria transmission for the inhabitants of tents in any part of the world where the vector mosquitoes are endophilic and susceptible to pyrethroids.

  6. Synergy between repellents and non-pyrethroid insecticides strongly extends the efficacy of treated nets against Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    N'Guessan Raphaël

    2007-03-01

    Full Text Available Abstract Background To manage the kdr pyrethroid-resistance in Anopheline malaria vectors, new compounds or new strategies are urgently needed. Recently, mixing repellents (DEET and a non-pyrethroid insecticide (propoxur was shown to be as effective as deltamethrin, a standard pyrethroid, under laboratory conditions, because of a strong synergy between the two compounds. In the present study, the interactions between two repellents (DEET and KBR 3023 and a non-pyrethroid insecticide (pyrimiphos methyl or PM on netting were investigated. The residual efficacy and the inhibition of blood feeding conferred by these mixtures were assessed against Anopheles gambiae mosquitoes. Methods DEET and KBR 3023 were mixed with pyrimiphos methyl (PM, a organophosphate (OP insecticide. The performance of mono- and bi-impregnated nets against adult mosquitoes was assessed using a miniaturized, experimental hut system (laboratory tunnel tests that allows expression of behavioural responses to insecticide, particularly the mortality and blood feeding effects. Results Both mixtures (PM+DEET and PM+KBR3023 induced 95% mortality for more than two months compared with less than one week for each compound used alone, then reflecting a strong synergy between the repellents and PM. A similar trend was observed with the blood feeding rates, which were significantly lower for the mixtures than for each component alone. Conclusion Synergistic interactions between organophosphates and repellents may be of great interest for vector control as they may contribute to increase the residual life of impregnated materials and improve the control of pyrethroid-resistance mosquitoes. These results prompt the need to evaluate the efficacy of repellent/non-pyrethroid insecticide mixtures against field populations of An. gambiae showing high level of resistance to Ops and pyrethroids.

  7. Olyset Duo® (a pyriproxyfen and permethrin mixture net: an experimental hut trial against pyrethroid resistant Anopheles gambiae and Culex quinquefasciatus in Southern Benin.

    Directory of Open Access Journals (Sweden)

    Corine Ngufor

    Full Text Available Alternative compounds which can complement pyrethroids on long-lasting insecticidal nets (LN in the control of pyrethroid resistant malaria vectors are urgently needed. Pyriproxyfen (PPF, an insect growth regulator, reduces the fecundity and fertility of adult female mosquitoes. LNs containing a mixture of pyriproxyfen and pyrethroid could provide personal protection through the pyrethroid component and reduce vector abundance in the next generation through the sterilizing effect of pyriproxyfen.The efficacy of Olyset Duo, a newly developed mixture LN containing pyriproxyfen and permethrin, was evaluated in experimental huts in southern Benin against pyrethroid resistant Anopheles gambiae and Culex quinquefasciatus. Comparison was made with Olyset Net® (permethrin alone and a LN with pyriproxyfen alone (PPF LN. Laboratory tunnel tests were performed to substantiate the findings in the experimental huts.Overall mortality of wild pyrethroid resistant An. gambiae s.s. was significantly higher with Olyset Duo than with Olyset Net (50% vs. 27%, P = 0.01. Olyset DUO was more protective than Olyset Net (71% vs. 3%, P<0.001. The oviposition rate of surviving blood-fed An. gambiae from the control hut was 37% whereas none of those from Olyset Duo and PPF LN huts laid eggs. The tunnel test results were consistent with the experimental hut results. Olyset Duo was more protective than Olyset Net in the huts against wild pyrethroid resistant Cx. quinquefasciatus although mortality rates of this species did not differ significantly between Olyset Net and Olyset Duo. There was no sterilizing effect on surviving blood-fed Cx. quinquefasciatus with the PPF-treated nets.Olyset Duo was superior to Olyset Net in terms of personal protection and killing of pyrethroid resistant An. gambiae, and sterilized surviving blood-fed mosquitoes. Mixing pyrethroid and pyriproxyfen on a LN shows potential for malaria control and management of pyrethroid resistant vectors by

  8. Synthetic biological networks

    International Nuclear Information System (INIS)

    Archer, Eric; Süel, Gürol M

    2013-01-01

    Despite their obvious relationship and overlap, the field of physics is blessed with many insightful laws, while such laws are sadly absent in biology. Here we aim to discuss how the rise of a more recent field known as synthetic biology may allow us to more directly test hypotheses regarding the possible design principles of natural biological networks and systems. In particular, this review focuses on synthetic gene regulatory networks engineered to perform specific functions or exhibit particular dynamic behaviors. Advances in synthetic biology may set the stage to uncover the relationship of potential biological principles to those developed in physics. (review article)

  9. Synthetic Base Fluids

    Science.gov (United States)

    Brown, M.; Fotheringham, J. D.; Hoyes, T. J.; Mortier, R. M.; Orszulik, S. T.; Randles, S. J.; Stroud, P. M.

    The chemical nature and technology of the main synthetic lubricant base fluids is described, covering polyalphaolefins, alkylated aromatics, gas-to-liquid (GTL) base fluids, polybutenes, aliphatic diesters, polyolesters, polyalkylene glycols or PAGs and phosphate esters.Other synthetic lubricant base oils such as the silicones, borate esters, perfluoroethers and polyphenylene ethers are considered to have restricted applications due to either high cost or performance limitations and are not considered here.Each of the main synthetic base fluids is described for their chemical and physical properties, manufacture and production, their chemistry, key properties, applications and their implications when used in the environment.

  10. Acute effects of binary mixtures of Type II pyrethroids and organophosphate insecticides on Oreochromis niloticus.

    Science.gov (United States)

    Fai, Patricia Bi Asanga; Tsobgny Kinfack, Joel Stephane; Tala Towa, Yannick Jordan

    2017-09-01

    Pyrethroid and organophosphate insecticides have been used for more than 20 years worldwide to control a variety of insect pest in different settings. These pesticides have been detected in a variety of environmental samples, including surface waters and sediments and therefore there is significant concern about their potential toxic effects on non-target organisms. Mixtures of compounds from these groups of pesticides have been found to frequently show enhanced toxicity but it has been a challenge to predict whether or not enhanced toxicity will occur for a given combination of compounds. This study therefore studied the effects of binary pyrethroid-organophosphate mixtures using cypermethrin, deltamethrin and dimethoate in an acute toxicity test system with Oreochromis niloticus. The 96 h LC50s for individual insecticides were 9.13 µg/l, 9.42 µg/l and 45.52 mg/l for cypermethrin, deltamethrin and dimethoate respectively. These showed that the pyrethroid insecticides were highly toxic to Oreochromis niloticus and were far more toxic than dimethoate. All mixtures were also more toxic than single insecticides throughout the concentration-response curve with mixtures resulting in mortality at concentrations which the individual pesticides in the mixture were below their respective NOECs. In addition, observed mixture toxicities deviated from the predicted mixture effects based either on the Concentration Addition (CA) or Independent Action (IA) models independent of mixture ratio. However, the extent of observed mixture mortality deviation was dependent on the effect level. Significant deviations (MDR > 2.0) were observed at lower concentrations indicating synergistic effects at lower and possibly environmentally relevant concentrations. This is not unexpected since organophosphate insecticides are known to inhibit acetylcholinesterase as well as inactivate esterase, resulting in reduced detoxification of pyrethroid insecticides and consequently greater

  11. Synthetic Biological Membrane (SBM)

    Data.gov (United States)

    National Aeronautics and Space Administration — The ultimate goal of the Synthetic Biological Membrane project is to develop a new type of membrane that will enable the wastewater treatment system required on...

  12. Simultaneous presence of DDT and pyrethroid residues in human breast milk from a malaria endemic area in South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Bouwman, H. [School for Environmental Sciences and Development, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom 2520 (South Africa)]. E-mail: drkhb@puk.ac.za; Sereda, B. [Agricultural Research Council, Plant Protection Research Institute, Private Bag X134 Queenswood, Pretoria 0121 (South Africa); Meinhardt, H.M. [South African Bureau of Standards, Testing and Conformity Services (Pty) Ltd, Private Bag X191, Pretoria 0001 (South Africa)

    2006-12-15

    DDT and pyrethroids were determined in 152 breast-milk samples from three towns in KwaZulu-Natal, South Africa, one of which had no need for DDT for malaria control. All compounds were found present in breast milk. Primiparae from one town had the highest mean {sigma}DDT whole milk levels (238.23 {mu}g/l), and multiparae from the same town had the highest means for permethrin (14.51 {mu}g/l), cyfluthrin (41.74 {mu}g/l), cypermethrin (4.24 {mu}g/l), deltamethrin (8.39 {mu}g/l), and {sigma}pyrethroid (31.5 {mu}g/l), most likely derived from agriculture. The ADI for DDT was only exceeded by infants from one town, but the ADI for pyrethroids was not exceeded. Since the ADI for DDT was recently reduced from 20 to 10 {mu}g/kg/bw, we suggest that this aspect be treated with concern. We therefore raise a concern based on toxicant interactions, due to the presence of four different pyrethroids and DDT. Breastfeeding however, remains safe under prevailing conditions. - The simultaneous presence of DDT and pyrethroid residues in breast milk raises the question of infant exposure and safety.

  13. Simultaneous presence of DDT and pyrethroid residues in human breast milk from a malaria endemic area in South Africa

    International Nuclear Information System (INIS)

    Bouwman, H.; Sereda, B.; Meinhardt, H.M.

    2006-01-01

    DDT and pyrethroids were determined in 152 breast-milk samples from three towns in KwaZulu-Natal, South Africa, one of which had no need for DDT for malaria control. All compounds were found present in breast milk. Primiparae from one town had the highest mean ΣDDT whole milk levels (238.23 μg/l), and multiparae from the same town had the highest means for permethrin (14.51 μg/l), cyfluthrin (41.74 μg/l), cypermethrin (4.24 μg/l), deltamethrin (8.39 μg/l), and Σpyrethroid (31.5 μg/l), most likely derived from agriculture. The ADI for DDT was only exceeded by infants from one town, but the ADI for pyrethroids was not exceeded. Since the ADI for DDT was recently reduced from 20 to 10 μg/kg/bw, we suggest that this aspect be treated with concern. We therefore raise a concern based on toxicant interactions, due to the presence of four different pyrethroids and DDT. Breastfeeding however, remains safe under prevailing conditions. - The simultaneous presence of DDT and pyrethroid residues in breast milk raises the question of infant exposure and safety

  14. Hybridization with synthetic oligonucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Szostak, J.W.; Stiles, J.I.; Tye, B.K.; Sherman, F.; Wu, R.

    1978-01-01

    Procedures are described for the use of synthetic oligonucleotides for Southern blot experiments and gene bank screening, and the effect of various mismatches on the efficiency of hybridization is demonstrated. The following topics are discussed: sensitivity vs. specificity, hybridization of a 12-mer to the lambda endolysin gene; hybridization of oligonucleotide probes to the E. coli lac operator; hybridization of synthetic probes to the CYC1 gene of yeast; and cloning eucaryotic genes. (HLW)

  15. Mammalian Synthetic Biology

    OpenAIRE

    Martella, Andrea; Pollard, Steven M; Dai, Junbiao; Cai, Yizhi

    2016-01-01

    The enabling technologies of synthetic biology are opening up new opportunities for engineering and enhancement of mammalian cells. This will stimulate diverse applications in many life science sectors such as regenerative medicine, development of biosensing cell lines, therapeutic protein production, and generation of new synthetic genetic regulatory circuits. Harnessing the full potential of these new engineering-based approaches requires the design and assembly of large DNA constructs-pote...

  16. Structure-related effects of pyrethroid insecticides on the lateral-line sense organ and on peripheral nerves of the clawed frog, Xenopus laevis

    NARCIS (Netherlands)

    Vijverberg, H.P.M.; Ruigt, GeS. F.; Bercken, J. van den

    1982-01-01

    The effects of seven different pyrethroid insecticides on the lateral-line sense organ and on peripheral nerves of the clawed frog, Xenopus laevis, were investigated by means of electrophysiological methods. The results show that two classes of pyrethroid can be clearly distinguished. (i)

  17. Measurement of Pyrethroids and Their Environmental Degradates in Fruits and Vegetables using a Modification of the Quick Easy Cheap Effective Rugged Safe (QuEChERS) Method

    Science.gov (United States)

    Pyrethroid insecticides are used extensively in agriculture and they, as well as their environmental degradates, may remain as residues on food products such as fruits and vegetables. Since pyrethroid degradates can be identical to the urinary markers used in human biomonitoring ...

  18. Environmentally relevant mixing ratios in cumulative assessments: a study on the correlation of blood and brain concentrations of a mixture of pyrethroid insecticides to neurotoxicity in the rat

    Science.gov (United States)

    Human exposure to multiple pyrethroid insecticides may occur because of their broad use on crops and for residential pest control. To address the potential health risk from co-exposure to pyrethroids, it is important to understand their disposition and toxicity in target organs ...

  19. Comparison of green sample preparation techniques in the analysis of pyrethrins and pyrethroids in baby food by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Petrarca, Mateus Henrique; Ccanccapa-Cartagena, Alexander; Masiá, Ana; Godoy, Helena Teixeira; Picó, Yolanda

    2017-05-12

    A new selective and sensitive liquid chromatography triple quadrupole mass spectrometry method was developed for simultaneous analysis of natural pyrethrins and synthetic pyrethroids residues in baby food. In this study, two sample preparation methods based on ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) and salting-out assisted liquid-liquid extraction (SALLE) were optimized, and then, compared regarding the performance criteria. Appropriate linearity in solvent and matrix-based calibrations, and suitable recoveries (75-120%) and precision (RSD values≤16%) were achieved for selected analytes by any of the sample preparation procedures. Both methods provided the analytical selectivity required for the monitoring of the insecticides in fruit-, cereal- and milk-based baby foods. SALLE, recognized by cost-effectiveness, and simple and fast execution, provided a lower enrichment factor, consequently, higher limits of quantification (LOQs) were obtained. Some of them too high to meet the strict legislation regarding baby food. Nonetheless, the combination of ultrasound and DLLME also resulted in a high sample throughput and environmental-friendly method, whose LOQs were lower than the default maximum residue limit (MRL) of 10μgkg -1 set by European Community for baby foods. In the commercial baby foods analyzed, cyhalothrin and etofenprox were detected in different samples, demonstrating the suitability of proposed method for baby food control. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Identification of proteins associated with pyrethroid resistance by iTRAQ-based quantitative proteomic analysis in Culex pipiens pallens.

    Science.gov (United States)

    Wang, Weijie; Lv, Yuan; Fang, Fujin; Hong, Shanchao; Guo, Qin; Hu, Shengli; Zou, Feifei; Shi, Linna; Lei, Zhentao; Ma, Kai; Zhou, Dan; Zhang, Donghui; Sun, Yan; Ma, Lei; Shen, Bo; Zhu, Changliang

    2015-02-10

    Mosquito control based on chemical insecticides is considered as an important element in the current global strategies for the control of mosquito-borne diseases. Unfortunately, the development of pyrethroid resistance in important vector mosquito species jeopardizes the effectiveness of insecticide-based mosquito control. To date, the mechanisms of pyrethroid resistance are still unclear. Recent advances in proteomic techniques can facilitate to identify pyrethroid resistance-associated proteins at a large-scale for improving our understanding of resistance mechanisms, and more importantly, for seeking some genetic markers used for monitoring and predicting the development of resistance. We performed a quantitative proteomic analysis between a deltamethrin-susceptible strain and a deltamethrin-resistant strain of laboratory population of Culex pipiens pallens using isobaric tags for relative and absolute quantitation (iTRAQ) analysis. Gene Ontology (GO) analysis was used to find the relative processes that these differentially expressed proteins were involved in. One differentially expressed protein was chosen to confirm by Western blot in the laboratory and field populations of Cx. pipiens pallens. We identified 30 differentially expressed proteins assigned into 10 different categories, including oxidoreductase activity, transporter activity, catalytic activity, structural constituent of cuticle and hypothetical proteins. GO analysis revealed that 25 proteins were sub-categorized into 35 hierarchically-structured GO classifications. Western blot results showed that CYP6AA9 as one of the up-regulated proteins was confirmed to be overexpressed in the deltamethrin-resistant strains compared with the deltamethrin-susceptible strains both in the laboratory and field populations. This is the first study to use modern proteomic tools for identifying pyrethroid resistance-related proteins in Cx. pipiens. The present study brought to light many proteins that were not

  1. Assessing the effects of Aedes aegypti kdr mutations on pyrethroid resistance and its fitness cost.

    Directory of Open Access Journals (Sweden)

    Luiz Paulo Brito

    Full Text Available Pyrethroids are the most used insecticide class worldwide. They target the voltage gated sodium channel (NaV, inducing the knockdown effect. In Aedes aegypti, the main dengue vector, the AaNaV substitutions Val1016Ile and Phe1534Cys are the most important knockdown resistance (kdr mutations. We evaluated the fitness cost of these kdr mutations related to distinct aspects of development and reproduction, in the absence of any other major resistance mechanism. To accomplish this, we initially set up 68 crosses with mosquitoes from a natural population. Allele-specific PCR revealed that one couple, the one originating the CIT-32 strain, had both parents homozygous for both kdr mutations. However, this pyrethroid resistant strain also presented high levels of detoxifying enzymes, which synergistically account for resistance, as revealed by biological and biochemical assays. Therefore, we carried out backcrosses between CIT-32 and Rockefeller (an insecticide susceptible strain for eight generations in order to bring the kdr mutation into a susceptible genetic background. This new strain, named Rock-kdr, was highly resistant to pyrethroid and presented reduced alteration of detoxifying activity. Fitness of the Rock-kdr was then evaluated in comparison with Rockefeller. In this strain, larval development took longer, adults had an increased locomotor activity, fewer females laid eggs, and produced a lower number of eggs. Under an inter-strain competition scenario, the Rock-kdr larvae developed even slower. Moreover, when Rockefeller and Rock-kdr were reared together in population cage experiments during 15 generations in absence of insecticide, the mutant allele decreased in frequency. These results strongly suggest that the Ae. aegypti kdr mutations have a high fitness cost. Therefore, enhanced surveillance for resistance should be priority in localities where the kdr mutation is found before new adaptive alleles can be selected for diminishing the

  2. Molecular diagnostics for detecting pyrethroid and abamectin resistance mutations in Tetranychus urticae.

    Science.gov (United States)

    Ilias, Aris; Vassiliou, Vassilis A; Vontas, John; Tsagkarakou, Anastasia

    2017-01-01

    Avermectin and pyrethroid resistance mutations (the G314D and the G326E in the glutamate gated chloride channels, and the F1538I in the voltage gated sodium channel) have been reported in the spider mite Tetranychus urticae, one of the most devastating pests of protected and open field crops worldwide. We developed three TaqMan molecular diagnostic assays for monitoring the presence and frequency of these mutations in T. urticae field populations. The TaqMan assays were validated against known genotypes and subsequently used to monitor the frequency of the resistance mutations in eleven T. urticae populations from Greece and Cyprus, with variable history of avermectin and pyrethroids applications. The frequency of the F1538I pyrethroid resistance mutation largely varied among samples, with highest frequencies (75%-97%) detected in four populations derived from protected and open field crops from Crete and Peloponnesus, low frequencies in three populations (2.5%-11%) from Attiki, Cyprus and Crete and not detected in four populations from Crete, Peloponnesus and Cyprus. The frequency of the abamectin resistance mutations G314D and G326E also varied across populations (from 0 to 100%), showing fixation in two populations (>97.5% for the G314D and 100% for the G326E), originating from rose greenhouses from Greece, low frequencies in three populations (5%-12.5%) also originating from rose greenhouses (Crete, Peloponnesus and Cyprus) and not detected in six populations from protected and open field vegetable crops. The TaqMan diagnostics showed higher resolution in detecting specific alleles in low frequency, compared to massive quantitative sequencing approaches previously employed. They can be used, together with classical bioassays, to support evidence - based insecticide resistance management strategies. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Simultaneous determination of eight metabolites of organophosphate and pyrethroid pesticides in urine.

    Science.gov (United States)

    Guo, Xin Y; Sun, Li S; Huang, Meng Y; Xu, Wei L; Wang, Ying; Wang, Na

    2017-01-02

    A simultaneous method for quantifying eight metabolites of organophosphate pesticides and pyrethroid pesticides in urine samples has been established. The analytes were extracted using liquid-liquid extraction coupled with WCX solid phase extraction (SPE) cartridges. Eight metabolites were chemically derivatized before analysis using gas chromatography-tandem mass spectrometry (GC-MS-MS). The separation was performed on a HP-5MS capillary column (30 m × 0.25 mm × 0.25 µm) with temperature programming. The detection was performed under electro-spray ionization (ESI) in multiple reaction monitoring (MRM) mode. An internal standard method was used. The extraction solvent, types of SPE cartridges and eluents were optimized by comparing the sample recoveries under different conditions. The results showed that the calibration curves of the five organophosphorus pesticides metabolites were linear in the range of 0.2-200 μg/L (r 2 ≥ 0.992) and that of the three pyrethroid pesticides metabolites were linear in the range of 0.025-250 μg/L (r 2 ≥ 0.991). The limits of detection (LODs, S/N ≥ 3) and the limits of quantification (LOQs, S/N ≥ 10) of the eight metabolites were 0.008-0.833 μg/L and 0.25-2.5 μg/L, respectively. The recoveries of the eight metabolites ranged from 54.08% to 82.49%. This efficient, stable, and cost-effective method is adequate to handle the large number of samples required for surveying the exposure level of organophosphorus and pyrethroid pesticides in the general population.

  4. Concentrations versus amounts of biomarkers in urine: a comparison of approaches to assess pyrethroid exposure

    Directory of Open Access Journals (Sweden)

    Bouchard Michèle

    2008-11-01

    Full Text Available Abstract Background Assessment of human exposure to non-persistent pesticides such as pyrethroids is often based on urinary biomarker measurements. Urinary metabolite levels of these pesticides are usually reported in volume-weighted concentrations or creatinine-adjusted concentrations measured in spot urine samples. It is known that these units are subject to intra- and inter-individual variations. This research aimed at studying the impact of these variations on the assessment of pyrethroid absorbed doses at individual and population levels. Methods Using data obtained from various adult and infantile populations, the intra and inter-individual variability in the urinary flow rate and creatinine excretion rate was first estimated. Individual absorbed doses were then calculated using volume-weighted or creatinine-adjusted concentrations according to published approaches and compared to those estimated from the amounts of biomarkers excreted in 15- or 24-h urine collections, the latter serving as a benchmark unit. The effect of the units of measurements (volume-weighted or creatinine adjusted concentrations or 24-h amounts on results of the comparison of pyrethroid biomarker levels between two populations was also evaluated. Results Estimation of daily absorbed doses of permethrin from volume-weighted or creatinine-adjusted concentrations of biomarkers was found to potentially lead to substantial under or overestimation when compared to doses reconstructed directly from amounts excreted in urine during a given period of time (-70 to +573% and -83 to +167%, respectively. It was also shown that the variability in creatinine excretion rate and urinary flow rate may introduce a bias in the case of between population comparisons. Conclusion The unit chosen to express biomonitoring data may influence the validity of estimated individual absorbed dose as well as the outcome of between population comparisons.

  5. Distribution of Pyrethroid Resistant Populations of Triatoma infestans in the Southern Cone of South America

    Science.gov (United States)

    Bustamante Gomez, Marinely; Gonçalves Diotaiuti, Liléia; Gorla, David E.

    2016-01-01

    Background A number of studies published during the last 15 years showed the occurrence of insecticide resistance in Triatoma infestans populations. The different toxicological profiles and mechanisms of resistance to insecticides is due to a genetic base and environmental factors, being the insecticide selective pressure the best studied among the last factors. The studies on insecticide resistance on T. infestans did not consider the effect of environmental factors that may influence the distribution of resistance to pyrethroid insecticides. To fill this knowledge gap, the present study aims at studying the association between the spatial distribution of pyrethroid resistant populations of T. infestans and environmental variables. Methodology/Principal Findings A total of 24 articles reporting on studies that evaluated the susceptibility to pyrethroids of 222 field-collected T. infestans populations were compiled. The relationship between resistance occurrence (according to different criteria) with environmental variables was studied using a generalized linear model. The lethal dose that kills 50% of the evaluated population (LD50) showed a strong linear relationship with the corresponding resistance ratio (RR50). The statistical descriptive analysis of showed that the frequency distribution of the Log (LD50) is bimodal, suggesting the existence of two statistical groups. A significant model including 5 environmental variables shows the geographic distribution of high and low LD50 groups with a particular concentration of the highest LD50 populations over the region identified as the putative center of dispersion of T. infestans. Conclusions/Significance The occurrence of these two groups concentrated over a particular region that coincides with the area where populations of the intermediate cytogenetic group were found might reflect the spatial heterogeneity of the genetic variability of T. infestans, that seems to be the cause of the insecticide resistance in

  6. Population-based biomonitoring of exposure to organophosphate and pyrethroid pesticides in New York City.

    Science.gov (United States)

    McKelvey, Wendy; Jacobson, J Bryan; Kass, Daniel; Barr, Dana Boyd; Davis, Mark; Calafat, Antonia M; Aldous, Kenneth M

    2013-01-01

    Organophosphates and pyrethroids are the most common classes of insecticides used in the United States. Widespread use of these compounds to control building infestations in New York City (NYC) may have caused higher exposure than in less-urban settings. The objectives of our study were to estimate pesticide exposure reference values for NYC and identify demographic and behavioral characteristics that predict exposures. The NYC Health and Nutrition Examination Survey was a population-based, cross-sectional study conducted in 2004 among adults ≥ 20 years of age. It measured urinary concentrations of organophosphate metabolites [dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate, diethylphosphate, diethylthiophosphate, and diethyldithiophosphate] in 883 participants, and pyrethroid metabolites [3-phenoxybenzoic acid (3-PBA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (trans-DCCA), 4-fluoro-3-phenoxybenzoic acid, and cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid] in 1,452 participants. We used multivariable linear regression to estimate least-squares geometric mean total dialkylphospate (ΣDAP) and 3-PBA concentrations across categories of predictors. The dimethyl organophosphate metabolites had the highest 95th percentile concentrations (87.4 μg/L and 74.7 μg/L for DMP and DMTP, respectively). The highest 95th percentiles among pyrethroid metabolites were measured for 3-PBA and trans-DCCA (5.23 μg/L and 5.94 μg/L, respectively). Concentrations of ΣDAP increased with increasing age, non-Hispanic white or black compared with Hispanic race/ethnicity, professional pesticide use, and increasing frequency of fruit consumption; they decreased with non-green vegetable consumption. Absolute differences in geometric mean urinary 3-PBA concentrations across categories of predictors were too small to be meaningful. Estimates of exposure to pyrethroids and dimethyl organophosphates were higher in

  7. Occurrence, compositional distribution, and toxicity assessment of pyrethroid insecticides in sediments from the fluvial systems of Chaohu Lake, Eastern China.

    Science.gov (United States)

    Wang, Ji-Zhong; Bai, Ya-Shu; Wu, Yakton; Zhang, Shuo; Chen, Tian-Hu; Peng, Shu-Chuan; Xie, Yu-Wei; Zhang, Xiao-Wei

    2016-06-01

    Surface sediment-associated synthetic pyrethroid insecticides (SPs) are known to pose high risks to the benthic organisms in Chaohu Lake, a shallow lake of Eastern China. However, the pollution status of the lake's tributaries and estuaries is still unknown. The present study was conducted to investigate the occurrence, compositional distribution, and toxicity of 12 currently used SPs in the surface sediments from four important tributaries, as well as in the sediment cores at their estuaries, using GC-MS for quantification. All SPs selected were detectable, with cypermethrin, es/fenvalerate, and permethrin dominant in both surface and core sediments, suggesting that these compounds were extensively applied. Urban samples contained the highest summed concentrations of the 12 SPs analyzed (Σ12SP) in both surface and core sediments compared with rural samples, suggesting that urban areas near aquatic environments posed high risks for SPs. The mean concentration of Σ12SP in surface sediments of each river was generally higher than that found in core sediments from its corresponding estuary, perhaps implying recent increases in SP usage. Surface sediments were significantly dominated by cypermethrin and permethrin, whereas core sediments were dominated by permethrin and es/fenvalerate. The compositional distributions demonstrated a spatial variation for surface sediments because urban sediments generally contained greater percentages of permethrin and cypermethrin, but rural sediments had significant levels of es/fenvalerate and cypermethrin. In all sediment cores, the percentage of permethrin gradually increased, whereas es/fenvalerate tended to decrease, from the bottom sediments to the top, indicating that the former represented fresh input, whereas the latter represented historical residue. Most urban samples would be expected to be highly toxic to benthic organisms due to the residue of SPs based on a calculation of toxic units (TUs) using toxicity data of the

  8. Synthetic guide star generation

    Science.gov (United States)

    Payne, Stephen A [Castro Valley, CA; Page, Ralph H [Castro Valley, CA; Ebbers, Christopher A [Livermore, CA; Beach, Raymond J [Livermore, CA

    2008-06-10

    A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

  9. Synthetic Aperture Sequential Beamforming

    DEFF Research Database (Denmark)

    Kortbek, Jacob; Jensen, Jørgen Arendt; Gammelmark, Kim Løkke

    2008-01-01

    A synthetic aperture focusing (SAF) technique denoted Synthetic Aperture Sequential Beamforming (SASB) suitable for 2D and 3D imaging is presented. The technique differ from prior art of SAF in the sense that SAF is performed on pre-beamformed data contrary to channel data. The objective...... is stored. The second stage applies the focused image lines from the first stage as input data. The SASB method has been investigated using simulations in Field II and by off-line processing of data acquired with a commercial scanner. The performance of SASB with a static image object is compared with DRF...

  10. What Are Synthetic Cannabinoids?

    Science.gov (United States)

    ... market and are intended to produce the same effects as illegal drugs. Some of these substances may have been around for years but have reentered the market in altered chemical forms, or due to renewed popularity. False Advertising Synthetic cannabinoid products are often labeled "not for ...

  11. Towards a synthetic chloroplast.

    Directory of Open Access Journals (Sweden)

    Christina M Agapakis

    2011-04-01

    Full Text Available The evolution of eukaryotic cells is widely agreed to have proceeded through a series of endosymbiotic events between larger cells and proteobacteria or cyanobacteria, leading to the formation of mitochondria or chloroplasts, respectively. Engineered endosymbiotic relationships between different species of cells are a valuable tool for synthetic biology, where engineered pathways based on two species could take advantage of the unique abilities of each mutualistic partner.We explored the possibility of using the photosynthetic bacterium Synechococcus elongatus PCC 7942 as a platform for studying evolutionary dynamics and for designing two-species synthetic biological systems. We observed that the cyanobacteria were relatively harmless to eukaryotic host cells compared to Escherichia coli when injected into the embryos of zebrafish, Danio rerio, or taken up by mammalian macrophages. In addition, when engineered with invasin from Yersinia pestis and listeriolysin O from Listeria monocytogenes, S. elongatus was able to invade cultured mammalian cells and divide inside macrophages.Our results show that it is possible to engineer photosynthetic bacteria to invade the cytoplasm of mammalian cells for further engineering and applications in synthetic biology. Engineered invasive but non-pathogenic or immunogenic photosynthetic bacteria have great potential as synthetic biological devices.

  12. Synthetic Metabolic Pathways

    DEFF Research Database (Denmark)

    topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and practical, Synthetic Metabolic Pathways: Methods and Protocols aims to ensure successful results in the further study...

  13. Synthetic growth reference charts

    NARCIS (Netherlands)

    Hermanussen, Michael; Stec, Karol; Aßmann, Christian; Meigen, Christof; Van Buuren, Stef

    2016-01-01

    Objectives: To reanalyze the between-population variance in height, weight, and body mass index (BMI), and to provide a globally applicable technique for generating synthetic growth reference charts. Methods: Using a baseline set of 196 female and 197 male growth studies published since 1831, common

  14. A formidable synthetic challenge

    Indian Academy of Sciences (India)

    Isolation and characterization of maoecrystal V, a C19 terpenoid, having potent and selective cytotoxicity towards HeLa cells was recently reported. Unusually complex pentacyclic molecular structure, presence of spirofused rings and several stereogenic centres posed a great synthetic challenge. In this short review, efforts ...

  15. Synthetic antiferromagnetic spintronics

    Science.gov (United States)

    Duine, R. A.; Lee, Kyung-Jin; Parkin, Stuart S. P.; Stiles, M. D.

    2018-03-01

    Spintronic and nanomagnetic devices often derive their functionality from layers of different materials and the interfaces between them. We discuss the opportunities that arise from synthetic antiferromagnets consisting of two or more ferromagnetic layers that are separated by metallic spacers or tunnel barriers and have antiparallel magnetizations.

  16. Pyrethroid insecticides in wild bird eggs from a World Heritage Listed Park: A case study in Doñana National Park (Spain).

    Science.gov (United States)

    Corcellas, Cayo; Andreu, Ana; Máñez, Manuel; Sergio, Fabrizio; Hiraldo, Fernando; Eljarrat, Ethel; Barceló, Damià

    2017-09-01

    Recent studies demonstrated that the common pyrethroid insecticides are present in aquatic biota tissues. In this study, 123 samples of unhatched eggs of 16 wild bird species collected from 2010 to 2012 in Doñana National and Natural Park were analysed to determine 13 pyrethroids. This study represents the first time that pyrethroids are detected in tissues of terrestrial biota, 93% of these samples being positive to those pollutants. Levels of total pyrethroids ranged from not detected to 324 ng g -1 lw. The samples were characterized by stable isotope analysis. Species with diets based on anthropogenic food showed higher levels of pyrethroids and lower values of δ 15 N. Finally, we characterized the isomers of pyrethroids and discerned some isomeric- and enantiomeric-specific accumulations. In particular, tetramethrin and cyhalothrin showed an enantiomeric-selective accumulation of one enantiomer, highlighting the need to assess toxicological effects of each enantiomer separately to be able to make a correct risk assessment of pyrethroids in birds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Synthetic Plant Defense Elicitors

    Directory of Open Access Journals (Sweden)

    Yasemin eBektas

    2015-01-01

    Full Text Available To defend themselves against invading pathogens plants utilize a complex regulatory network that coordinates extensive transcriptional and metabolic reprogramming. Although many of the key players of this immunity-associated network are known, the details of its topology and dynamics are still poorly understood. As an alternative to forward and reverse genetic studies, chemical genetics-related approaches based on bioactive small molecules have gained substantial popularity in the analysis of biological pathways and networks. Use of such molecular probes can allow researchers to access biological space that was previously inaccessible to genetic analyses due to gene redundancy or lethality of mutations. Synthetic elicitors are small drug like molecules that induce plant defense responses, but are distinct from known natural elicitors of plant immunity. While the discovery of the some synthetic elicitors had already been reported in the 1970s, recent breakthroughs in combinatorial chemical synthesis now allow for inexpensive high-throughput screens for bioactive plant defense-inducing compounds. Along with powerful reverse genetics tools and resources available for model plants and crop systems, comprehensive collections of new synthetic elicitors will likely allow plant scientists to study the intricacies of plant defense signaling pathways and networks in an unparalleled fashion. As synthetic elicitors can protect crops from diseases, without the need to be directly toxic for pathogenic organisms, they may also serve as promising alternatives to conventional biocidal pesticides, which often are harmful for the environment, farmers and consumers. Here we are discussing various types of synthetic elicitors that have been used for studies on the plant immune system, their modes-of-action as well as their application in crop protection.

  18. Environmental fate of pyrethroids in urban and suburban stream sediments and the appropriateness of Hyalella azteca model in determining ecological risk.

    Science.gov (United States)

    Palmquist, Katherine; Fairbrother, Anne; Salatas, Johanna; Guiney, Patrick D

    2011-07-01

    According to several recent studies using standard acute Hyalella azteca sediment bioassays, increased pyrethroid use in urban and suburban regions in California has resulted in the accumulation of toxic concentrations of pyrethroids in sediments of area streams and estuaries. However, a critical review of the literature indicates that this is likely an overestimation of environmental risk. Hyalella azteca is consistently the most susceptible organism to both aqueous and sediment-associated pyrethroid exposures when compared to a suite of other aquatic taxa. In some cases, H. azteca LC50 values are less than the community HC10 values, suggesting that the amphipod is an overly conservative model for community- or ecosystem-level impacts of sediment-associated pyrethroids. Further, as a model for responses of field populations of H. azteca, the laboratory bioassays considerably overestimate exposure, because the amphipod is more appropriately characterized as an epibenthic organism, not a true sediment dweller; H. azteca preferentially inhabit aquatic macrophytes, periphyton mats, and leaf litter, which drastically reduces their exposure to contaminated sediments. Sediment-bound pyrethroids are transported via downstream washing of fine particulates resulting in longer range transport but also more efficient sequestration of the chemical. In addition, site-specific variables such as sediment organic carbon content, grain size, temperature, and microbial activity alter pyrethroid bioavailability, degradation, and toxicity on a microhabitat scale. The type and source of the carbon in particular, influences the pyrethroid sequestering ability of sediments. The resulting irregular distribution of pyrethroids in stream sediments suggests that sufficient nonimpacted habitat may exist as refugia for resident sediment-dwelling organisms for rapid recolonization to occur. Given these factors, we argue that the amphipod model provides, at best, a screening level assessment of

  19. A Mutation in the Intracellular Loop III/IV of Mosquito Sodium Channel Synergizes the Effect of Mutations in Helix IIS6 on Pyrethroid Resistance

    Science.gov (United States)

    Wang, Lingxin; Nomura, Yoshiko; Du, Yuzhe; Liu, Nannan; Zhorov, Boris S.

    2015-01-01

    Activation and inactivation of voltage-gated sodium channels are critical for proper electrical signaling in excitable cells. Pyrethroid insecticides promote activation and inhibit inactivation of sodium channels, resulting in prolonged opening of sodium channels. They preferably bind to the open state of the sodium channel by interacting with two distinct receptor sites, pyrethroid receptor sites PyR1 and PyR2, formed by the interfaces of domains II/III and I/II, respectively. Specific mutations in PyR1 or PyR2 confer pyrethroid resistance in various arthropod pests and disease vectors. Recently, a unique mutation, N1575Y, in the cytoplasmic loop linking domains III and IV (LIII/IV) was found to coexist with a PyR2 mutation, L1014F in IIS6, in pyrethroid-resistant populations of Anopheles gambiae. To examine the role of this mutation in pyrethroid resistance, N1575Y alone or N1575Y + L1014F were introduced into an Aedes aegypti sodium channel, AaNav1-1, and the mutants were functionally examined in Xenopus oocytes. N1575Y did not alter AaNav1-1 sensitivity to pyrethroids. However, the N1575Y + L1014F double mutant was more resistant to pyrethroids than the L1014F mutant channel. Further mutational analysis showed that N1575Y could also synergize the effect of L1014S/W, but not L1014G or other pyrethroid-resistant mutations in IS6 or IIS6. Computer modeling predicts that N1575Y allosterically alters PyR2 via a small shift of IIS6. Our findings provide the molecular basis for the coexistence of N1575Y with L1014F in pyrethroid resistance, and suggest an allosteric interaction between IIS6 and LIII/IV in the sodium channel. PMID:25523031

  20. Contribution of pyrethroids in large urban rivers to sediment toxicity assessed with benthic invertebrates Chironomus dilutus: A case study in South China.

    Science.gov (United States)

    Cheng, Fei; Li, Huizhen; Qi, Hongxue; Han, Qian; You, Jing

    2017-12-01

    The importance of pyrethroids as potential stressors to benthic organisms has gradually become evident in urban creeks; however, the occurrence and toxicity of sediment-associated pyrethroids are rarely studied in large rivers. In this context, 10 sediments from a large urban river (Guangzhou reach of the Pearl River in China) were assessed for pyrethroid occurrence and sediment toxicity to the benthic invertebrate Chironomus dilutus. One half of the sediments exhibited lethality to C. dilutus in a 10-d exposure and all surviving midges showed significant change of enzymatic activity. Moreover, mortality occurred during a 20-d exposure for all the sediments, in accordance with the high hazard quotients to benthic species estimated from pyrethroid residues in sediment. Pyrethroids were detectable in all sediments with the concentrations ranging from 2.43 to 61.2 ng/g dry weight, and permethrin and cypermethrin dominated pyrethroid composition. Acute toxic units for pyrethroids ranged from 0.03 to 0.56 (cypermethrin accounted for 13-81%) and showed a direct relationship with sediment mortality among the midges. This is consistent with the studies on small creeks in Guangzhou in which sediment-bound cypermethrin was found as a main stressor to benthic invertebrates. Comparatively, sediment toxicity and pyrethroid residues in large rivers were significantly lower than those in nearby creeks (urban tributaries). The difference may be partially explained by differing flow rates and water-carrying capacity among waterbodies at different scales; further validation is required. Overall, extensive use of pyrethroids has caused a threat to benthic species not only in small creeks but also in large rivers. Environ Toxicol Chem 2017;36:3367-3375. © 2017 SETAC. © 2017 SETAC.

  1. Differences of susceptibility of five triatomine species to pyrethroid insecticides - implications for Chagas disease vector control

    Directory of Open Access Journals (Sweden)

    Alfredo Martins de Oliveira Filho

    1999-09-01

    Full Text Available As pyrethroids are presently the favored group of insecticides to control triatomines, we performed a series of bioassays to determine the intrinsic activity of some of the main compounds used in the control campaigns, against five of the main species of triatomines to be controlled. Comparing the insecticides it can be seen that lambdacyhalothrin is more effective than the other three pyrethroids, both considering the LD50 and 99 for all the three species with comparable results. On Triatoma infestans the LD50 of lambdacyhalothrin was followed by that of alfacypermethrin, cyfluthrin and deltamethrin. On Rhodnius prolixus the sequence, in decreasing order of activity, was lambdacyhalothrin, alfacypermethrin, deltamethrin and cyfluthrin. Some modifications can be seen when we compare the LD99, that has more to see to what happens in the field. T. brasiliensis showed to be as sensible to lambdacyhalothrin as T. infestans, the most susceptible for this product. By the other side T. sordida is the least susceptible considering the LD99 of this insecticide.

  2. Carbamate and Pyrethroid Resistance in the Akron Strain of Anopheles gambiae

    Science.gov (United States)

    Mutunga, James M.; Anderson, Troy D.; Craft, Derek T.; Gross, Aaron D.; Swale, Daniel R.; Tong, Fan; Wong, Dawn M.; Carlier, Paul R.; Bloomquist, Jeffrey R.

    2015-01-01

    Insecticide resistance in the malaria vector, Anopheles gambiae is a serious problem, epitomized by the multi-resistant Akron strain, originally isolated in the country of Benin. Here we report resistance in this strain to pyrethroids and DDT (13-fold to 35-fold compared to the susceptible G3 strain), but surprisingly little resistance to etofenprox, a compound sometimes described as a “pseudo-pyrethroid.” There was also strong resistance to topically-applied commercial carbamates (45-fold to 81-fold), except for the oximes aldicarb and methomyl. Biochemical assays showed enhanced cytochrome P450 monooxygenase and carboxylesterase activity, but not that of glutathione-S-transferase. A series of substituted α,α,α,-trifluoroacetophenone oxime methylcarbamates were evaluated for enzyme inhibition potency and toxicity against G3 and Akron mosquitoes. The compound bearing an unsubstituted phenyl ring showed the greatest toxicity to mosquitoes of both strains. Low cross resistance in Akron was retained by all analogs in the series. Kinetic analysis of acetylcholinesterase activity and its inhibition by insecticides in the G3 strain showed inactivation rate constants greater than that of propoxur, and against Akron enzyme inactivation rate constants similar to that of aldicarb. However, inactivation rate constants against recombinant human AChE were essentially identical to that of the G3 strain. Thus, the acetophenone oxime carbamates described here, though potent insecticides that control resistant Akron mosquitoes, require further structural modification to attain acceptable selectivity and human safety. PMID:26047119

  3. The effect of insecticide synergists on the response of scabies mites to pyrethroid acaricides.

    Science.gov (United States)

    Pasay, Cielo; Arlian, Larry; Morgan, Marjorie; Gunning, Robin; Rossiter, Louise; Holt, Deborah; Walton, Shelley; Beckham, Simone; McCarthy, James

    2009-01-01

    Permethrin is the active component of topical creams widely used to treat human scabies. Recent evidence has demonstrated that scabies mites are becoming increasingly tolerant to topical permethrin and oral ivermectin. An effective approach to manage pesticide resistance is the addition of synergists to counteract metabolic resistance. Synergists are also useful for laboratory investigation of resistance mechanisms through their ability to inhibit specific metabolic pathways. To determine the role of metabolic degradation as a mechanism for acaricide resistance in scabies mites, PBO (piperonyl butoxide), DEF (S,S,S-tributyl phosphorotrithioate) and DEM (diethyl maleate) were first tested for synergistic activity with permethrin in a bioassay of mite killing. Then, to investigate the relative role of specific metabolic pathways inhibited by these synergists, enzyme assays were developed to measure esterase, glutathione S-transferase (GST) and cytochrome P450 monooxygenase (cytochrome P450) activity in mite extracts. A statistically significant difference in median survival time of permethrin-resistant Sarcoptes scabiei variety canis was noted when any of the three synergists were used in combination with permethrin compared to median survival time of mites exposed to permethrin alone (presistant mites compared to sensitive mites. These findings indicate the potential utility of synergists in reversing resistance to pyrethroid-based acaricides and suggest a significant role of metabolic mechanisms in mediating pyrethroid resistance in scabies mites.

  4. Susceptibility of Triatoma brasiliensis from state of Ceará, Northeastern Brazil, to the pyrethroid deltamethrin

    Directory of Open Access Journals (Sweden)

    Ivan Vieira Sonoda

    2010-05-01

    Full Text Available After controlling Triatoma infestans in Brazil, other species of triatomine that were considered minor in the transmission of Chagas disease became important. The persistence of Triatoma brasiliensis in Northeastern Brazil, associated with reinfection of domestic environments recently sprayed with pyrethroids, may be a signal of susceptibility alteration of this species to this insecticide. Specimens of T. brasiliensis from the municipality of Tauá, state of Ceará, were captured before and one year after spraying. They were submitted to bioassays using deltamethrin. The LD50 ranged from 0.19-0.33 ng of deltamethrin/nymph. The resistance ratio among samples from Tauá varied from 1.16-1.79 in the samples captured before the spraying and 1.00-1.74 in the samples captured one year after spraying, demonstrating that the two populations were equally susceptible to deltamethrin. The small difference in susceptibility between the two captures suggests that T. brasiliensis obtained in the second capture are from new invasions of the domestic environment and that the insecticide did not select resistant individuals. Therefore, it is suggested that T. brasiliensis control be carried out supplementing the regular use of pyrethroids with complementary measures, such as improvement of the dwellings and health education.

  5. Susceptibility to chlorpyrifos in pyrethroid-resistant populations of Aedes aegypti (Diptera: Culicidae) from Mexico.

    Science.gov (United States)

    Lopez, Beatriz; Ponce, Gustavo; Gonzalez, Jessica A; Gutierrez, Selene M; Villanueva, Olga K; Gonzalez, Gabriela; Bobadilla, Cristina; Rodriguez, Iram P; Black, William C; Flores, Adriana E

    2014-05-01

    Resistance to the organophosphate insecticide chlorpyrifos was evaluated in females from six strains of Aedes aegypti (L.) that expressed high levels of cross-resistance to eight pyrethroid insecticides. Relative to LC50 and LC90 at 24 h of a susceptible New Orleans (NO) strain, three strains were highly resistant to chlorpyrifos (Coatzacoalcos, resistance ratio [RRLC90 = 11.97; Pozarica, RRLC90 = 12.98; and Cosoleacaque, RRLC50 = 13.94 and RRLC90 = 17.57), one strain was moderately resistant (Veracruz, RRLC90 = 5.92), and two strains were susceptible (Tantoyuca and Martinez de la Torre, RRLC50 and RRLC90 < 5) in bottle bioassays according to Centers for Disease Control and Prevention. Furthermore, high levels of alpha- or beta-esterase activity in the sample populations were correlated with resistance, suggesting that esterase activity may be a mechanism causing the development of organophosphate resistance in these populations. Overall, the populations in this study were less resistant to chlorpyrifos than to pyrethroids. Rotation of insecticides used in control activities is recommended to delay or minimize the occurrence of high levels of resistance to chlorpyrifos among local populations of Ae. aegypti. The diagnostic dose and diagnostic time for chlorpyrifos resistance monitoring was determined to be 85 microg per bottle and 30 min, respectively, using the susceptible NO strain.

  6. Toxic heritage: Maternal transfer of pyrethroid insecticides and sunscreen agents in dolphins from Brazil.

    Science.gov (United States)

    Alonso, Mariana B; Feo, Maria Luisa; Corcellas, Cayo; Gago-Ferrero, Pablo; Bertozzi, Carolina P; Marigo, Juliana; Flach, Leonardo; Meirelles, Ana Carolina O; Carvalho, Vitor L; Azevedo, Alexandre F; Torres, João Paulo M; Lailson-Brito, José; Malm, Olaf; Diaz-Cruz, M Silvia; Eljarrat, Ethel; Barceló, Damià

    2015-12-01

    Pyrethroids (PYR) and UV filters (UVF) were investigated in tissues of paired mother-fetus dolphins from Brazilian coast in order to investigate the possibility of maternal transfer of these emerging contaminants. Comparison of PYR and UVF concentrations in maternal and fetal blubber revealed Franciscana transferred efficiently both contaminants to fetuses (F/M > 1) and Guiana dolphin transferred efficiently PYR to fetuses (F/M > 1) different than UVF (F/M < 1). PYR and UVF concentrations in fetuses were the highest-ever reported in biota (up to 6640 and 11,530 ng/g lw, respectively). Muscle was the organ with the highest PYR and UVF concentrations (p < 0.001), suggesting that these two classes of emerging contaminants may have more affinity for proteins than for lipids. The high PYR and UVF concentrations found in fetuses demonstrate these compounds are efficiently transferred through placenta. This study is the first to report maternal transfer of pyrethroids and UV filters in marine mammals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Synergism studies with binary mixtures of pyrethroid, carbamate and organophosphate insecticides on Frankliniella occidentalis (Pergande).

    Science.gov (United States)

    Bielza, Pablo; Espinosa, Pedro J; Quinto, Vicente; Abellán, Jaime; Contreras, Josefina

    2007-01-01

    The major mechanism of resistance to most insecticides in Frankliniella occidentalis (Pergande) is metabolic, piperonyl butoxide (PBO) suppressible, mediated by cytochrome-P450 monooxygenases and conferring cross-resistance among insecticide classes. The efficacy of insecticide mixtures of acrinathrin, methiocarb, formetanate and chlorpyrifos was studied by topical exposure in strains of F. occidentalis selected for resistance to each insecticide. The method consisted in combining increasing concentrations of one insecticide with a constant low rate of the second one as synergist. Acrinathrin activity against F. occidentalis was enhanced by carbamate insecticides, methiocarb being a much better synergist than formetanate. Monooxygenase action on the carbamates would prevent degradation of the pyrethroid, hence providing a level of synergism by competitive substrate inhibition. However, the number of insecticides registered for control of F. occidentalis is very limited, and they are needed for antiresistance strategies such as mosaics and rotations. Therefore, a study was made of the synergist effect of other carbamates not used against thrips, such as carbofuran and carbosulfan, against a susceptible strain and a field strain. Neither carbamate showed synergism to acrinathrin in the susceptible strain, but both did in the field strain, carbosulfan being a better synergist than carbofuran. The data obtained indicate that low rates of carbamates could be used as synergists to restore some pyrethroid susceptibility in F. occidentalis. Copyright (c) 2006 Society of Chemical Industry.

  8. Synthetic antifreeze peptide and synthetic gene coding for its production

    OpenAIRE

    1991-01-01

    A synthetic antifreeze peptide and a synthetic gene coding for the antifreeze peptide have been produced. The antifreeze peptide has a greater number of repeating amino acid sequences than is present in the native antifreeze peptides from winter flounder upon which the synthetic antifreeze peptide was modeled. Each repeating amino acid sequence has two polar amino acid residues which are spaced a controlled distance apart so that the antifreeze peptide may inhibit ice formation. The synthetic...

  9. Cumulative risk assessment of the exposure to pyrethroids through fruits consumption in China - Based on a 3-year investigation.

    Science.gov (United States)

    Li, Zhixia; Nie, Jiyun; Lu, Zeqi; Xie, Hanzhong; Kang, Lu; Chen, Qiusheng; Li, An; Zhao, Xubo; Xu, Guofeng; Yan, Zhen

    2016-10-01

    In the present study, the long-term and short-term cumulative risks of pyrethroids exposured for the Chinese general population and children through fruits consumption were evaluated. A total of 1450 fruit samples and seven pyrethroids were included based on the pesticide residues monitoring programme of China from 2013 to 2015. The exposure was estimated using both deterministic approach and semi-probabilistic model for comparison. The hazard index approach was used to assess cumulative risk. 26% of samples contained pyrethroid residues with concentrations ranged from 0.0050 mg/kg to 1.2 mg/kg, of which 30% simultaneously with 2-4 mixture residues. Results demonstrated that the cumulative health risks were extremely low for both general population and children (1-6 years old) of China in the long term. Acute risk estimations calculated by deterministic method were several or many times overestimated than the results based on semi-probabilistic method. Acute cumulative exposure of children to pyrethroid compounds in 0.76% samples were exceeded 1 in worst case scenario. More detailed assessments with adequate data in the future use probabilistic method is expected to reduce the uncertainties of cumulative dietary exposure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Electropolymerized multiwalled carbon nanotubes/polypyrrole fiber for solid-phase microextraction and its applications in the determination of pyrethroids.

    Science.gov (United States)

    Chen, Liangbi; Chen, Wenfeng; Ma, Chunhua; Du, Dan; Chen, Xi

    2011-03-15

    A novel solid-phase microextraction (SPME) fiber coated with multiwalled carbon nanotubes/polypyrrole (MWCNTs/Ppy) was prepared with an electrochemical method and used for the extraction of pyrethroids in natural water samples. The results showed that the MWCNTs/Ppy coated fiber had high organic stability, and remarkable acid and alkali resistance. In addition, the MWCNTs/Ppy coated fiber was more effective and superior to commercial PDMS and PDMS/DVD fibers in extracting pyrethroids in natural water samples. Under optimized conditions, the calibration curves were found to be linear from 0.001 to 10 μg mL(-1) for five of the six pyrethroids studied, the exception being fenvalerate (which was from 0.005 to 10 μg mL(-1)), and detection limits were within the range 0.12-0.43 ng mL(-1). The recoveries of the pyrethroids spiked in water samples at 10 ng mL(-1) ranged from 83 to 112%. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. ELISA AND SOL-GEL BASED IMMUNOAFFINITY PURIFICATION OF THE PYRETHROID BIOALLETHRIN IN FOOD AND ENVIRONMENTAL SAMPLES

    Science.gov (United States)

    The peer-reviewed article describes the development of a new sol-gel based immunoaffinity purification procedure and an immunoassay for the pyrethroid bioallethrin. The immunoaffinity chromatography procedure was applied to food samples providing an efficient cleanup prior to im...

  12. Poisoning suicide with ingestion of the pyrethroids alpha-cypermethrin and deltamethrin and the antidepressant mirtazapine: A case report.

    Science.gov (United States)

    Boumba, Vassiliki A; Rallis, Georgios N; Vougiouklakis, Theodore

    2017-05-01

    This case report describes a death attributed to the intake of the pyrethroid insecticides, alpha-cypermethrin and deltamethrin, and the antidepressant mirtazapine. The autopsy findings showed absence of external traumatic injuries and internal generalized visceral congestion, edema and cyanosis. The toxicological results revealed the presence of a toxic concentration of mirtazapine (12.5mg/L and 10.7mg/L in blood and urine, respectively) and high concentrations of pyrethroids (2.46mg/L alpha-cypermethrin and 2.40mg/L deltamethrin in blood, and 0.41mg/L alpha-cypermethrin and 0.46mg/L deltamethrin in urine, respectively). Blood ethanol concentration was 0.75g/L. All the evidence - from autopsy, police investigation and toxicology - was consistent with the intentional self-harm of the deceased. The current case was determined and recorded as a poisoning suicide. Cause of death of the deceased was reported as the synergistic toxicity of the ingested pyrethroids and mirtazapine. The presence of a significant blood ethanol concentration was considered a secondary contributory factor to the fatal outcome. The case presented herein is the first death attributed to poisoning from ingestion of pyrethroids in combination with mirtazapine, with the intention of the victim to cause self-harm, with corresponding toxicology results. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Home Use of a Pyrethroid-Containing Pesticide and Facial Paresthesia in a Toddler: A Case Report

    Directory of Open Access Journals (Sweden)

    Alexandra Perkins

    2016-08-01

    Full Text Available Paresthesias have previously been reported among adults in occupational and non-occupational settings after dermal contact with pyrethroid insecticides. In this report, we describe a preverbal 13-month-old who presented to his primary care pediatrician with approximately 1 week of odd facial movements consistent with facial paresthesias. The symptoms coincided with a period of repeat indoor spraying at his home with a commercially available insecticide containing two active ingredients in the pyrethroid class. Consultation by the Northwest Pediatric Environmental Health Specialty Unit and follow-up by the Washington State Department of Health included urinary pyrethroid metabolite measurements during and after the symptomatic period, counseling on home clean up and use of safer pest control methods. The child’s symptoms resolved soon after home cleanup. A diagnosis of pesticide-related illness due to pyrethroid exposure was made based on the opportunity for significant exposure (multiple applications in areas where the child spent time, supportive biomonitoring data, and the consistency and temporality of symptom findings (paresthesias. This case underscores the vulnerability of children to uptake pesticides, the role of the primary care provider in ascertaining an exposure history to recognize symptomatic illness, and the need for collaborative medical and public health efforts to reduce significant exposures in children.

  14. Transcriptional response of rat frontal cortex following acute In Vivo exposure to the pyrethroid insecticides permethrin and deltamethrin

    Directory of Open Access Journals (Sweden)

    Tornero-Velez Rogelio

    2008-11-01

    Full Text Available Abstract Background Pyrethroids are neurotoxic pesticides that interact with membrane bound ion channels in neurons and disrupt nerve function. The purpose of this study was to characterize and explore changes in gene expression that occur in the rat frontal cortex, an area of CNS affected by pyrethroids, following an acute low-dose exposure. Results Rats were acutely exposed to either deltamethrin (0.3 – 3 mg/kg or permethrin (1 – 100 mg/kg followed by collection of cortical tissue at 6 hours. The doses used range from those that cause minimal signs of intoxication at the behavioral level to doses well below apparent no effect levels in the whole animal. A statistical framework based on parallel linear (SAM and isotonic regression (PIR methods identified 95 and 53 probe sets as dose-responsive. The PIR analysis was most sensitive for detecting transcripts with changes in expression at the NOAEL dose. A sub-set of genes (Camk1g, Ddc, Gpd3, c-fos and Egr1 was then confirmed by qRT-PCR and examined in a time course study. Changes in mRNA levels were typically less than 3-fold in magnitude across all components of the study. The responses observed are consistent with pyrethroids producing increased neuronal excitation in the cortex following a low-dose in vivo exposure. In addition, Significance Analysis of Function and Expression (SAFE identified significantly enriched gene categories common for both pyrethroids, including some relating to branching morphogenesis. Exposure of primary cortical cell cultures to both compounds resulted in an increase (~25% in the number of neurite branch points, supporting the results of the SAFE analysis. Conclusion In the present study, pyrethroids induced changes in gene expression in the frontal cortex near the threshold for decreases in ambulatory motor activity in vivo. The penalized regression methods performed similarly in detecting dose-dependent changes in gene transcription. Finally, SAFE analysis of

  15. The dynamics of pyrethroid resistance in Anopheles arabiensis from Zanzibar and an assessment of the underlying genetic basis.

    Science.gov (United States)

    Jones, Christopher M; Haji, Khamis A; Khatib, Bakari O; Bagi, Judit; Mcha, Juma; Devine, Gregor J; Daley, Matthew; Kabula, Bilali; Ali, Abdullah S; Majambere, Silas; Ranson, Hilary

    2013-12-06

    The emergence of pyrethroid resistance in the malaria vector, Anopheles arabiensis, threatens to undermine the considerable gains made towards eliminating malaria on Zanzibar. Previously, resistance was restricted to the island of Pemba while mosquitoes from Unguja, the larger of the two islands of Zanzibar, were susceptible. Here, we characterised the mechanism(s) responsible for resistance on Zanzibar using a combination of gene expression and target-site mutation assays. WHO resistance bioassays were conducted using 1-5d old adult Anopheles gambiae s.l. collected between 2011 and 2013 across the archipelago. Synergist assays with the P450 inhibitor piperonyl-butoxide were performed in 2013. Members of the An. gambiae complex were PCR-identified and screened for target-site mutations (kdr and Ace-1). Gene expression in pyrethroid resistant An. arabiensis from Pemba was analysed using whole-genome microarrays. Pyrethroid resistance is now present across the entire Zanzibar archipelago. Survival to the pyrethroid lambda-cyhalothrin in bioassays conducted in 2013 was 23.5-54.3% on Unguja and 32.9-81.7% on Pemba. We present evidence that resistance is mediated, in part at least, by elevated P450 monoxygenases. Whole-genome microarray scans showed that the most enriched gene terms in resistant An. arabiensis from Pemba were associated with P450 activity and synergist assays with PBO completely restored susceptibility to pyrethroids in both islands. CYP4G16 was the most consistently over-expressed gene in resistant mosquitoes compared with two susceptible strains from Unguja and Dar es Salaam. Expression of this P450 is enriched in the abdomen and it is thought to play a role in hydrocarbon synthesis. Microarray and qPCR detected several additional genes putatively involved in this pathway enriched in the Pemba pyrethroid resistant population and we hypothesise that resistance may be, in part, related to alterations in the structure of the mosquito cuticle. None of the

  16. Associations between dietary factors and urinary concentrations of organophosphate and pyrethroid metabolites in a Canadian general population.

    Science.gov (United States)

    Ye, Ming; Beach, Jeremy; Martin, Jonathan W; Senthilselvan, Ambikaipakan

    2015-10-01

    Few studies to date have characterized the relationships between diet and urinary concentrations of pesticides. In the current study, associations between dietary factors and urinary concentrations of organophosphate and pyrethroid metabolites were examined in a Canadian general population using data from the Canadian Health Measures Survey (CHMS). In the CHMS, urinary concentrations of dialkylphosphate (DAP) and pyrethroid metabolites were measured in 5604 participants aged 6-79 years. Associations between dietary factors and total concentrations of DAP (ΣDAP) and pyrethroid metabolites (ΣPYR) were examined. Over 90% of participants had at least one type of DAP and 99.8% had pyrethroid metabolites detectable in urine samples. After adjusting for age, sex, race/ethnicity, immigrant status and body mass index, ΣDAP among participants with high (3rd tertile) fruit consumption was 1.43 (95% CI: 1.26-1.61) times the concentration among those with low (1st tertile) consumption. ΣDAP was also positively associated with vegetable consumption, for those with high consumption ΣDAP being 1.33 times (95% CI: 1.16-1.52) the concentration for those with low consumption. ΣPYR among participants with high vegetable consumption was 1.42 (95% CI: 1.23-1.66) times the concentration among those with low vegetable consumption. ΣPYR was also positively associated with pulses/nuts consumption (p-valuesorganophosphate and pyrethroid metabolites suggest greater regulation of pesticide use on food products may help to reduce pesticide exposures and associated health risks among the general population. Copyright © 2015 Elsevier GmbH. All rights reserved.

  17. Standardization in synthetic biology.

    Science.gov (United States)

    Müller, Kristian M; Arndt, Katja M

    2012-01-01

    Synthetic Biology is founded on the idea that complex biological systems are built most effectively when the task is divided in abstracted layers and all required components are readily available and well-described. This requires interdisciplinary collaboration at several levels and a common understanding of the functioning of each component. Standardization of the physical composition and the description of each part is required as well as a controlled vocabulary to aid design and ensure interoperability. Here, we describe standardization initiatives from several disciplines, which can contribute to Synthetic Biology. We provide examples of the concerted standardization efforts of the BioBricks Foundation comprising the request for comments (RFC) and the Registry of Standardized Biological parts as well as the international Genetically Engineered Machine (iGEM) competition.

  18. Optical synthetic aperture radar

    Science.gov (United States)

    Ilovitsh, Asaf; Zach, Shlomo; Zalevsky, Zeev

    2013-06-01

    A method is proposed for increasing the resolution of an object and overcoming the diffraction limit of an optical system installed on top of a moving imaging system, such as an airborne platform or satellite. The resolution improvement is obtained via a two-step process. First, three low resolution differently defocused images are captured and the optical phase is retrieved using an improved iterative Gershberg-Saxton based algorithm. The phase retrieval allows numerical back propagation of the field to the aperture plane. Second, the imaging system is shifted and the first step is repeated. The obtained optical fields at the aperture plane are combined and a synthetically increased lens aperture is generated along the direction of movement, yielding higher imaging resolution. The method resembles a well-known approach from the microwave regime called the synthetic aperture radar in which the antenna size is synthetically increased along the platform propagation direction. The proposed method is demonstrated via Matlab simulation as well as through laboratory experiment.

  19. Batrachotoxin, Pyrethroids, and BTG 502 Share Overlapping Binding Sites on Insect Sodium ChannelsS⃞

    Science.gov (United States)

    Du, Yuzhe; Garden, Daniel; Khambay, Bhupinder; Zhorov, Boris S.

    2011-01-01

    Batrachotoxin (BTX), a steroidal alkaloid, and pyrethroid insecticides bind to distinct but allosterically coupled receptor sites on voltage-gated sodium channels and cause persistent channel activation. BTX presumably binds in the inner pore, whereas pyrethroids are predicted to bind at the lipid-exposed cavity formed by the short intracellular linker-helix IIS4-S5 and transmembrane helices IIS5 and IIIS6. The alkylamide insecticide (2E,4E)-N-(1,2-dimethylpropyl)-6-(5-bromo-2-naphthalenyl)-2,4-hexadienamide (BTG 502) reduces sodium currents and antagonizes the action of BTX on cockroach sodium channels, suggesting that it also binds inside the pore. However, a pyrethroid-sensing residue, Phe3i17 in IIIS6, which does not face the pore, is essential for the activity of BTG 502 but not for BTX. In this study, we found that three additional deltamethrin-sensing residues in IIIS6, Ile3i12, Gly3i14, and Phe3i16 (the latter two are also BTX-sensing), and three BTX-sensing residues, Ser3i15 and Leu3i19 in IIIS6 and Phe4i15 in IVS6, are all critical for BTG 502 action on cockroach sodium channels. Using these data as constraints, we constructed a BTG 502 binding model in which BTG 502 wraps around IIIS6, probably making direct contacts with all of the above residues on the opposite faces of the IIIS6 helix, except for the putative gating hinge Gly3i14. BTG 502 and its inactive analog DAP 1855 antagonize the action of deltamethrin. The antagonism was eliminated by mutations of Ser3i15, Phe3i17, Leu3i19, and Phe4i15 but not by mutations of Ile3i12, Gly3i14, and Phe3i16. Our analysis revealed a unique mode of action of BTG 502, its receptor site overlapping with those of both BTX and deltamethrin. PMID:21680776

  20. Batrachotoxin, pyrethroids, and BTG 502 share overlapping binding sites on insect sodium channels.

    Science.gov (United States)

    Du, Yuzhe; Garden, Daniel; Khambay, Bhupinder; Zhorov, Boris S; Dong, Ke

    2011-09-01

    Batrachotoxin (BTX), a steroidal alkaloid, and pyrethroid insecticides bind to distinct but allosterically coupled receptor sites on voltage-gated sodium channels and cause persistent channel activation. BTX presumably binds in the inner pore, whereas pyrethroids are predicted to bind at the lipid-exposed cavity formed by the short intracellular linker-helix IIS4-S5 and transmembrane helices IIS5 and IIIS6. The alkylamide insecticide (2E,4E)-N-(1,2-dimethylpropyl)-6-(5-bromo-2-naphthalenyl)-2,4-hexadienamide (BTG 502) reduces sodium currents and antagonizes the action of BTX on cockroach sodium channels, suggesting that it also binds inside the pore. However, a pyrethroid-sensing residue, Phe(3i17) in IIIS6, which does not face the pore, is essential for the activity of BTG 502 but not for BTX. In this study, we found that three additional deltamethrin-sensing residues in IIIS6, Ile(3i12), Gly(3i14), and Phe(3i16) (the latter two are also BTX-sensing), and three BTX-sensing residues, Ser(3i15) and Leu(3i19) in IIIS6 and Phe(4i15) in IVS6, are all critical for BTG 502 action on cockroach sodium channels. Using these data as constraints, we constructed a BTG 502 binding model in which BTG 502 wraps around IIIS6, probably making direct contacts with all of the above residues on the opposite faces of the IIIS6 helix, except for the putative gating hinge Gly(3i14). BTG 502 and its inactive analog DAP 1855 antagonize the action of deltamethrin. The antagonism was eliminated by mutations of Ser(3i15), Phe(3i17), Leu(3i19), and Phe(4i15) but not by mutations of Ile(3i12), Gly(3i14), and Phe(3i16). Our analysis revealed a unique mode of action of BTG 502, its receptor site overlapping with those of both BTX and deltamethrin.

  1. Synthetic cannabis and respiratory depression.

    Science.gov (United States)

    Jinwala, Felecia N; Gupta, Mayank

    2012-12-01

    In recent years, synthetic cannabis use has been increasing in appeal among adolescents, and its use is now at a 30 year peak among high school seniors. The constituents of synthetic cannabis are difficult to monitor, given the drug's easy accessibility. Currently, 40 U.S. states have banned the distribution and use of some known synthetic cannabinoids, and have included these drugs in the Schedule I category. The depressive respiratory effect in humans caused by synthetic cannabis inhalation has not been thoroughly investigated in the medical literature. We are the first to report, to our knowledge, two cases of self-reported synthetic cannabis use leading to respiratory depression and necessary intubation.

  2. A residue in the transmembrane segment 6 of domain I in insect and mammalian sodium channels regulate differential sensitivities to pyrethroid insecticides

    Science.gov (United States)

    Oliveira, Eugênio E.; Du, Yuzhe; Nomura, Yoshiko; Dong, Ke

    2013-01-01

    Voltage-gated sodium channels are critical for electrical signaling in the nervous system. Pyrethroid insecticides exert their toxic action by modifying the gating of sodium channels. A valine to methionine mutation in the transmembrane segment 6 of domain I (IS6) of sodium channels from tobacco budworms (Heliothis virescens) has been shown to alter channel gating and reduce insect sodium channel sensitivity to pyrethroids. A valine to leucine substitution was subsequently reported in pyrethroid-resistant bedbug populations. Intriguingly, pyrethroid-resistant mammalian sodium channels possess an isoleucine at the corresponding position. To determine whether different substitutions at this position alter channel gating and confer pyrethroid resistance, we made valine to methionine, isoleucine or leucine substitutions at the corresponding position, V409, in a cockroach sodium channel and examined the gating properties and pyrethroid sensitivity of the three mutants in Xenopus oocytes. All three mutations reduced the channel sensitivity to three pyrethroids (permethrin, cismethrin and deltamethrin). V409M, but not V409I or V409L, caused 6-7 mV depolarizing shifts in the voltage dependences of both activation and inactivation. V409M and V409L slowed channel activation kinetics and accelerated open-state deactivation kinetics, but V409I did not. Furthermore, the substitution of isoleucine with valine, but not with methionine nor leucine, at the corresponding position in a rat skeletal muscle sodium channel, rNav1.4, enhanced channel sensitivity to deltamethrin. Collectively, our study highlights an important role of residues at 409 in regulating not only sodium channel gating, but also the differential sensitivities of insect and mammalian sodium channels to pyrethroids. PMID:23764339

  3. Nontarget Effects of Aerial Mosquito Adulticiding With Water-Based Unsynergized Pyrethroids on Honey Bees and Other Beneficial Insects in an Agricultural Ecosystem of North Greece

    Science.gov (United States)

    2014-05-01

    SHORT COMMUNICATION Nontarget Effects of Aerial Mosquito Adulticiding With Water-Based Unsynergized Pyrethroids on Honey Bees and Other Beneficial...beneÞcial nontarget organisms were used: honey bees (domesticated hives), family Apidae (Apis mellifera L.); mealybug destroyers, family Coccinellidae...py- rethroid) and d-phenothrin (type I pyrethroid) are toxic to beneÞcial insects such as honey bees (LC50s 0.05 and 0.067 g per bee for

  4. First Data on Resistance to Pyrethroids in Wild Populations of Aedes albopictus from Spain.

    Science.gov (United States)

    Bengoa, Mikel; Eritja, Roger; Delacour, Sarah; Miranda, Miguel Ángel; Sureda, Antonio; Lucientes, Javier

    2017-09-01

    The invasive mosquito, Aedes albopictus, found in Spain since 2004, is a competent vector of yellow fever, Zika, dengue, and chikungunya viruses among other diseases. Although controversial, the use of adulticiding is a relevant tool for vector control and could be crucial for the management of any possible outbreak of imported diseases. We present the 1st study in Spain on the susceptibility of field populations from Barcelona, Peñíscola, Castellón, and Mallorca of Ae. albopictus to several pyrethroids using either bioassays under the World Health Organization methodology and biochemical tests. In the bioassays, the discriminating concentrations were calculated using a local, susceptible laboratory strain. Different susceptibility levels were found for some combinations of populations and products. The biochemical tests carried out by enzymatic analysis supported these results, showing an overexpression of glutathione S-transferase activity in 1 population.

  5. Micronuclei induction in Rana catesbeiana tadpoles by the pyrethroid insecticide lambda-cyhalothrin

    Directory of Open Access Journals (Sweden)

    Campana Marcela Alejandra

    2003-01-01

    Full Text Available Pyrethroid lambda-cyhalothrin genotoxicity was evaluated using the micronucleus test in Rana catesbeiana tadpoles. The effects of concentration and exposure time on the micronuclei frequency were studied in blood smears obtained from tadpoles exposed to four concentrations (0.02, 0.1, 0.2 and 0.4 mg/L of the compound for 24, 48, 72 and 96 h and 8, 15, 20 and 30 days. As a positive control, tadpoles were exposed to cyclophosphamide (5 mg/L. The micronucleated cell frequency was expressed per 1,000 cells. R. catesbeiana tadpoles exposed to increasing concentrations of lambda-cyhalothrin showed an increase in the micronuclei frequency in peripheral blood. Tadpoles exposed to cyclophosphamide (CP also showed a significant increase in micronucleated erythrocytes which peaked after 15 days. These results suggest that R. catesbeiana tadpoles may provide a useful model for monitoring water pollution.

  6. Valve Movement response of the Mussel, Mytilus galloprovincialis to cypermethrin (pyrethroid-insecticide)

    International Nuclear Information System (INIS)

    Ait Ayad, M.; Ait Fdill, M.; Mouabad, A.

    2009-01-01

    The Moroccan lagoons are economically important and ecologically very sensitive. They are affected by pollution from a range of sources, especially by agricultural pollution from the adjacent agricultural areas that use huge quantities of organic pesticides. These products can be harmful to non target organisms by drainage. A biological monitor for the water quality surveillance using mussels is described. It was deigned to characterize the toxicity of the Cyermethrin (pesticide-pyrethroid ) to the coastal environment by assessing its sublethal effect on valve movement of the mussel Mytilus galloprovincialis. In this method the valve behaviour of exposed mussels to Cypermathrin is compared with normal valve opening (control and the reduction in the time of normal opening is used as a rapid response to detect contaminants. (Author)

  7. Incoordination, Paralysis and Recovery after Pyrethroid Treatment on Nymphs III of Triatoma infestans (Hemiptera: Reduviidae

    Directory of Open Access Journals (Sweden)

    Raúl A Alzogaray

    1997-05-01

    Full Text Available Symptoms of poisoning for deltamethrin and cis-permethrin on nymphs III of Triatoma infestans were described. The time required for incoordination and paralysis were determined. Deltamethrin was equal or more rapid in the onset of the first effect (accordingly to dose, and cis-permethrin in the onset of the second one. There were no significant differences between incoordination doses 50% (IncD50s at different times for the two pyrethroids. They showed equivalent incoordination power, but the nymphs treated with deltamethrin recovered slightly more rapid and in greater amount than the nymphs treated with cis-permethrin. The recovery was inhibited by the simultaneus application of piperonyl butoxide. This result suggests that biotransformation by mixed-function microsomal oxidases are involved in the process of recovery

  8. Synthetic cannabinoids revealing adrenoleukodystrophy.

    Science.gov (United States)

    Fellner, Avi; Benninger, Felix; Djaldetti, Ruth

    2016-02-01

    We report a 41-year-old man who presented with a first generalized tonic-clonic seizure after recent consumption of a synthetic cannabinoid. MRI showed extensive bilateral, mainly frontal, white matter lesions. Blood analysis for very long chain fatty acids was compatible with adrenoleukodystrophy, and a missense mutation in the ABCD1 gene confirmed the diagnosis. We hypothesize that cannabinoid use might have contributed to metabolic decompensation with subacute worsening of the underlying condition. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. CASH vs. SYNTHETIC CDOs

    Directory of Open Access Journals (Sweden)

    Silviu Eduard Dinca

    2015-12-01

    Full Text Available During the past few years, in the recent post-crisis aftermath, global asset managers are constantly searching new ways to optimize their investment portfolios while financial and banking institutions around the world are exploring new alternatives to better secure their financing and refinancing demands altogether with the enhancement of their risk management capabilities. We will exhibit herewith a comparison between the true-sale and synthetic CDO securitizations as financial markets-based funding, investment and risks mitigation techniques, highlighting certain key structuring and implementation specifics on each of them.

  10. Single and mixture impacts of two pyrethroids on damselfly predatory behavior and physiological biomarkers.

    Science.gov (United States)

    Kunce, Warren; Stoks, Robby; Johansson, Frank

    2017-09-01

    Direct mortality due to toxicity of single pesticide exposure along a concentration gradient, while the most common, is only one important parameter for assessing the effects of pesticide contamination on aquatic ecosystems. Sub-lethal toxicity can induce changes in an organism's behavior and physiology that may have population-level ramifications and consequences for ecosystem health. Additionally, the simultaneous detection of multiple contaminants in monitored watersheds stresses the importance of gaining a greater understanding of the toxicities of combined exposures, particularly at low, environmentally relevant concentrations. Using larvae of the Azure Damselfly (Coenagrion puella), we conducted a combined exposure investigation of two widely-used pyrethroid insecticides presumed to share the same neurotoxic mechanism of action, and estimated their effect on predatory ability, mobility and three physiological biomarkers (Glutathione S-transferase; GST, respiratory electron transport system; ETS, and malondialdehyde; MDA). Deltamethrin exposure (0.065μg/L and 0.13μg/L) was found to reduce the predatory ability, but it did not affect the larvae's mobility. Esfenvalerate exposure (0.069μg/L and 0.13μg/L), on the other hand, induced no significant changes in predatory ability or mobility. The decrease in predatory ability after the combination exposure (0.067μg/L deltamethrin and 0.12μg/L esfenvalerate) did not significantly differ from the impact of the single deltamethrin exposures. Glutathione-S-transferase was induced after single esfenvalerate exposure and the lower deltamethrin concentration exposure, but seemingly inhibited after exposure to the higher concentration of deltamethrin as well as the combination of both pyrethroids. Our data indicate that sub-lethal exposure to deltamethrin reduces predatory ability and suggest that sub-lethal combined exposure to deltamethrin and esfenvalerate inhibits the GST detoxification pathway. These effects can

  11. The effect of insecticide synergists on the response of scabies mites to pyrethroid acaricides.

    Directory of Open Access Journals (Sweden)

    Cielo Pasay

    Full Text Available Permethrin is the active component of topical creams widely used to treat human scabies. Recent evidence has demonstrated that scabies mites are becoming increasingly tolerant to topical permethrin and oral ivermectin. An effective approach to manage pesticide resistance is the addition of synergists to counteract metabolic resistance. Synergists are also useful for laboratory investigation of resistance mechanisms through their ability to inhibit specific metabolic pathways.To determine the role of metabolic degradation as a mechanism for acaricide resistance in scabies mites, PBO (piperonyl butoxide, DEF (S,S,S-tributyl phosphorotrithioate and DEM (diethyl maleate were first tested for synergistic activity with permethrin in a bioassay of mite killing. Then, to investigate the relative role of specific metabolic pathways inhibited by these synergists, enzyme assays were developed to measure esterase, glutathione S-transferase (GST and cytochrome P450 monooxygenase (cytochrome P450 activity in mite extracts. A statistically significant difference in median survival time of permethrin-resistant Sarcoptes scabiei variety canis was noted when any of the three synergists were used in combination with permethrin compared to median survival time of mites exposed to permethrin alone (p<0.0001. Incubation of mite homogenates with DEF showed inhibition of esterase activity (37%; inhibition of GST activity (73% with DEM and inhibition of cytochrome P450 monooxygenase activity (81% with PBO. A 7-fold increase in esterase activity, a 4-fold increase in GST activity and a 2-fold increase in cytochrome P450 monooxygenase activity were observed in resistant mites compared to sensitive mites.These findings indicate the potential utility of synergists in reversing resistance to pyrethroid-based acaricides and suggest a significant role of metabolic mechanisms in mediating pyrethroid resistance in scabies mites.

  12. Evidence of field-evolved resistance to organophosphates and pyrethroids in Chrysoperla carnea (Neuroptera: Chrysopidae).

    Science.gov (United States)

    Pathan, Attaullah Khan; Sayyed, Ali H; Aslam, Muhammad; Razaq, Muhammad; Jilani, Ghulam; Saleem, Mushtaq Ahmad

    2008-10-01

    The toxicity of some of the most commonly used insecticides in the organophosphate and pyrethroid classes were investigated against different Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) populations collected over three consecutive years (2005-2007). The populations were tested using leaf dip bioassays for residual effects and topical applications to measure the response of larvae that would come into direct contact with field application of insecticides. In leaf dip assays, the LC50 (micrograms per milliliter; 120 h) values for chlorpyrifos and profenofos were in the range of 59.3-1,023 and 180.02-1,118 respectively. The LC50 values for lambda-cyhalthrin, alphamethrin, and deltamethrin were 359.08-2,677, 112.9-923.5, and 47.81-407.03, respectively. The toxicity for the above insecticides in topical application was similar to toxicity in leaf dip assays. The susceptibility of a laboratory population, which was locally developed and designated as (Lab-PK), to deltamethrin was comparable with another susceptible laboratory population. Resistance ratios for five field populations were generally low to medium for deltamethrin, but high to very high for chlorpyrifos, profenofos, lambda-cyhalthrin and alphamethrin compared with the Lab-PK population. Our data also suggested that the five field populations had multiple resistance to two classes of insecticides. The populations showed resistance to two organophosphates tested and to lambda-cyhalthrin and alphamethrin; however, resistance to deltamethrin was only found at two locations. This pattern indicates occurrence of two divergent patterns of resistance within pyrethroids. The resistance to the insecticides was stable across 3 yr, suggesting field selection for general fitness had also taken place in various populations of C. carnea. The broad spectrum of resistance and stability of resistance to insecticides in C. carnea in the current study suggested that it could be a prime candidate for mass releases

  13. Prenatal Exposure to DDT and Pyrethroids for Malaria Control and Child Neurodevelopment: The VHEMBE Cohort, South Africa.

    Science.gov (United States)

    Eskenazi, Brenda; An, Sookee; Rauch, Stephen A; Coker, Eric S; Maphula, Angelina; Obida, Muvhulawa; Crause, Madelein; Kogut, Katherine R; Bornman, Riana; Chevrier, Jonathan

    2018-04-06

    Although indoor residual spraying (IRS) with dichlorodiphenyltrichloroethane (DDT) and pyrethroids effectively controls malaria, it potentially increases human exposure to these insecticides. Previous studies suggest that prenatal exposure to these insecticides may impact human neurodevelopment. We aimed to estimate the effects of maternal insecticide exposure and neurodevelopment of toddlers living in a malaria-endemic region currently using IRS. The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) is a birth cohort of 752 mother-child pairs in Limpopo, South Africa. We measured maternal exposure to DDT and its breakdown product, dichlorodiphenyldichloroethylene (DDE), in maternal serum, and measured pyrethroid metabolites in maternal urine. We assessed children's neurodevelopment at 1 and 2 y of age using the Bayley Scales of Infant Development, third edition (BSID-III), and examined associations with maternal exposure. DDT and DDE were not associated with significantly lower scores for any BSID-III scale. In contrast, each 10-fold increase in cis -DCCA, trans -DCCA, and 3-phenoxybenzoic acid were associated, respectively, with a -0.63 (95% CI: -1.14, -0.12), -0.48 (95% CI: -0.92, -0.05), and -0.58 (-1.11, -0.06) decrement in Social-Emotional scores at 1 y of age. In addition, each 10-fold increase in maternal cis -DBCA levels was associated with significant decrements at 2 y of age in Language Composite scores and Expressive Communication scores [β=-1.74 (95% CI: -3.34, -0.13) and β=-0.40 (95% CI: -0.77, -0.04), respectively, for a 10-fold increase]. Significant differences by sex were estimated for pyrethroid metabolites and motor function scores at 2 y of age, with higher scores for boys and lower scores for girls. Prenatal exposure to pyrethroids may be associated at 1 y of age with poorer social-emotional development. At 2 y of age, poorer language development was observed with higher prenatal pyrethroid levels. Considering the

  14. Methods of Analysis - Determination of Pyrethroid Insecticides in Water and Sediment Using Gas Chromatography/Mass Spectrometry

    Science.gov (United States)

    Hladik, Michelle; Smalling, Kelly L.; Kuivila, Kathryn

    2009-01-01

    A method for the determination of 14 pyrethroid insecticides in environmental water and sediment samples is described. The method was developed by the U.S. Geological Survey in response to increasing concern over the effects of pyrethroids on aquatic organisms. The pyrethroids included in this method are ones that are applied to many agricultural and urban areas. Filtered water samples are extracted for pyrethroids using solid-phase extraction (SPE) with no additional cleanup steps. Sediment and soil samples are extracted using a microwave-assisted extraction system, and the pyrethroids of interest are separated from co-extracted matrix interferences by passing the extracts through stacked graphitized carbon and alumina SPE cartridges, along with the use of high-performance liquid chromatography and gel-permeation chromatography (HPLC/GPC). Quantification of the pyrethroids from the extracted water and sediment samples is done using gas chromatography with mass spectrometry (GC/MS) or gas chromatography with tandem mass spectrometry (GC/MS/MS). Recoveries in test water samples fortified at 10 ng/L ranged from 83 to 107 percent, and recoveries in test sediment samples fortified at 10 ug/kg ranged from 82 to 101 percent; relative standard deviations ranged from 5 to 9 percent in the water samples and 3 to 9 percent in the sediment samples. Method detection limits (MDLs), calculated using U.S. Environmental Protection Agency procedures (40 CFR 136, Appendix B), in water ranged from 2.0 to 6.0 ng/L using GC/MS and 0.5 to 1.0 ng/L using GC/MS/MS. For sediment, the MDLs ranged from 1.0 to 2.6 ug/kg dry weight using GC/MS and 0.2 to 0.5 ug/kg dry weight using GC/MS/MS. The matrix-spike recoveries for each compound, when averaged for 12 environmental water samples, ranged from 84 to 96 percent, and when averaged for 27 environmental sediment samples, ranged from 88 to 100 percent.

  15. Synthetic collective intelligence.

    Science.gov (United States)

    Solé, Ricard; Amor, Daniel R; Duran-Nebreda, Salva; Conde-Pueyo, Núria; Carbonell-Ballestero, Max; Montañez, Raúl

    2016-10-01

    Intelligent systems have emerged in our biosphere in different contexts and achieving different levels of complexity. The requirement of communication in a social context has been in all cases a determinant. The human brain, probably co-evolving with language, is an exceedingly successful example. Similarly, social insects complex collective decisions emerge from information exchanges between many agents. The difference is that such processing is obtained out of a limited individual cognitive power. Computational models and embodied versions using non-living systems, particularly involving robot swarms, have been used to explore the potentiality of collective intelligence. Here we suggest a novel approach to the problem grounded in the genetic engineering of unicellular systems, which can be modified in order to interact, store memories or adapt to external stimuli in collective ways. What we label as Synthetic Swarm Intelligence defines a parallel approach to the evolution of computation and swarm intelligence and allows to explore potential embodied scenarios for decision making at the microscale. Here, we consider several relevant examples of collective intelligence and their synthetic organism counterparts. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Space Synthetic Biology Project

    Science.gov (United States)

    Howard, David; Roman, Monsi; Mansell, James (Matt)

    2015-01-01

    Synthetic biology is an effort to make genetic engineering more useful by standardizing sections of genetic code. By standardizing genetic components, biological engineering will become much more similar to traditional fields of engineering, in which well-defined components and subsystems are readily available in markets. Specifications of the behavior of those components and subsystems can be used to model a system which incorporates them. Then, the behavior of the novel system can be simulated and optimized. Finally, the components and subsystems can be purchased and assembled to create the optimized system, which most often will exhibit behavior similar to that indicated by the model. The Space Synthetic Biology project began in 2012 as a multi-Center effort. The purpose of this project was to harness Synthetic Biology principals to enable NASA's missions. A central target for application was to Environmental Control & Life Support (ECLS). Engineers from NASA Marshall Space Flight Center's (MSFC's) ECLS Systems Development Branch (ES62) were brought into the project to contribute expertise in operational ECLS systems. Project lead scientists chose to pursue the development of bioelectrochemical technologies to spacecraft life support. Therefore, the ECLS element of the project became essentially an effort to develop a bioelectrochemical ECLS subsystem. Bioelectrochemical systems exploit the ability of many microorganisms to drive their metabolisms by direct or indirect utilization of electrical potential gradients. Whereas many microorganisms are capable of deriving the energy required for the processes of interest (such as carbon dioxide (CO2) fixation) from sunlight, it is believed that subsystems utilizing electrotrophs will exhibit smaller mass, volume, and power requirements than those that derive their energy from sunlight. In the first 2 years of the project, MSFC personnel conducted modeling, simulation, and conceptual design efforts to assist the

  17. Life after the synthetic cell

    DEFF Research Database (Denmark)

    Rasmussen, Steen

    2010-01-01

    Nature asked eight synthetic-biology experts about the implications for science and society of the “synthetic cell” made by the J. Craig Venter Institute (JCVI). The institute's team assembled, modified and implanted a synthesized genome into a DNA-free bacterial shell to make a self-replicating ......Nature asked eight synthetic-biology experts about the implications for science and society of the “synthetic cell” made by the J. Craig Venter Institute (JCVI). The institute's team assembled, modified and implanted a synthesized genome into a DNA-free bacterial shell to make a self...

  18. Synthetic biology and occupational risk.

    Science.gov (United States)

    Howard, John; Murashov, Vladimir; Schulte, Paul

    2017-03-01

    Synthetic biology is an emerging interdisciplinary field of biotechnology that involves applying the principles of engineering and chemical design to biological systems. Biosafety professionals have done an excellent job in addressing research laboratory safety as synthetic biology and gene editing have emerged from the larger field of biotechnology. Despite these efforts, risks posed by synthetic biology are of increasing concern as research procedures scale up to industrial processes in the larger bioeconomy. A greater number and variety of workers will be exposed to commercial synthetic biology risks in the future, including risks to a variety of workers from the use of lentiviral vectors as gene transfer devices. There is a need to review and enhance current protection measures in the field of synthetic biology, whether in experimental laboratories where new advances are being researched, in health care settings where treatments using viral vectors as gene delivery systems are increasingly being used, or in the industrial bioeconomy. Enhanced worker protection measures should include increased injury and illness surveillance of the synthetic biology workforce; proactive risk assessment and management of synthetic biology products; research on the relative effectiveness of extrinsic and intrinsic biocontainment methods; specific safety guidance for synthetic biology industrial processes; determination of appropriate medical mitigation measures for lentiviral vector exposure incidents; and greater awareness and involvement in synthetic biology safety by the general occupational safety and health community as well as by government occupational safety and health research and regulatory agencies.

  19. Finding Hope in Synthetic Biology.

    Science.gov (United States)

    Takala, Tuija

    2017-04-01

    For some, synthetic biology represents great hope in offering possible solutions to many of the world's biggest problems, from hunger to sustainable development. Others remain fearful of the harmful uses, such as bioweapons, that synthetic biology can lend itself to, and most hold that issues of biosafety are of utmost importance. In this article, I will evaluate these points of view and conclude that although the biggest promises of synthetic biology are unlikely to become reality, and the probability of accidents is fairly substantial, synthetic biology could still be seen to benefit humanity by enhancing our ethical understanding and by offering a boost to world economy.

  20. Investigating knockdown resistance (kdr) mechanism against pyrethroids/DDT in the malaria vector Anopheles funestus across Africa.

    Science.gov (United States)

    Irving, Helen; Wondji, Charles S

    2017-08-09

    Understanding the molecular basis of insecticide resistance is key to improve the surveillance and monitoring of malaria vector populations under control. In the major malaria vector Anopheles funestus, little is currently known about the role of the knockdown resistance (kdr) mechanism. Here, we investigated the presence and contribution of knockdown resistance (kdr) to pyrethroids/DDT resistance observed in Anopheles funestus across Africa. Pyrosequencing genotyping and sequencing of the voltage gated sodium channel (VGSC) gene did not detect the common L1014F mutation in field collected An. funestus across Africa. Amplification and cloning of the full-length of the sodium channel gene in pyrethroid resistant mosquitoes revealed evidences of alternative splicing events with three transcripts of 2092, 2061 and 2117 amino acids (93% average similarity to An. gambiae). Several amino acid changes were detected close to the domain II of the protein such as L928R, F938 W, I939S, L802S and T1008 M. However, all these mutations are found at low frequency and their role in pyrethroid resistance could not be established. The presence of the exclusive alternative splicing at exon 19 was not associated with resistance phenotype. Analysis of patterns of genetic diversity of the VGSC gene revealed a high polymorphism level of this gene across Africa with no evidence of directional selection suggesting a limited role for knockdown resistance in pyrethroid resistance in An. funestus. Patterns of genetic differentiation correlate with previous observations of the existence of barriers to gene flow Africa-wide with southern population significantly differentiated from other regions. Despite an apparent limited role of knockdown resistance in An. funestus, it is necessary to continue to monitor the contribution of the mutations detected here as increasing selection from insecticide-based interventions may change the dynamic in field populations as previously observed in other

  1. Two-step microextraction combined with high performance liquid chromatographic analysis of pyrethroids in water and vegetable samples.

    Science.gov (United States)

    Mukdasai, Siriboon; Thomas, Chunpen; Srijaranai, Supalax

    2014-03-01

    Dispersive liquid microextraction (DLME) combined with dispersive µ-solid phase extraction (D-µ-SPE) has been developed as a new approach for the extraction of four pyrethroids (tetramethrin, fenpropathrin, deltamethrin and permethrin) prior to the analysis by high performance liquid chromatography (HPLC) with UV detection. 1-Octanol was used as the extraction solvent in DLME. Magnetic nanoparticles (Fe3O4) functionalized with 3-aminopropyl triethoxysilane (APTS) were used as the dispersive in DLME and as the adsorbent in D-µ-SPE. The extracted pyrethroids were separated within 30 min using isocratic elution with acetonitrile:water (72:28). The factors affecting the extraction efficiency were investigated. Under the optimum conditions, the enrichment factors were in the range of 51-108. Linearity was obtained in the range 0.5-400 ng mL(-1) (tetramethrin) and 5-400 ng mL(-1) (fenpropathrin, deltamethrin and permethrin) with the correlation coefficients (R(2)) greater than 0.995. Detection limits were 0.05-2 ng mL(-1) (water samples) and 0.02-2.0 ng g(-1) (vegetable samples). The relative standard deviations of peak area varied from 1.8 to 2.5% (n=10). The extraction recoveries of the four pyrethroids in field water and vegetable samples were 91.7-104.5%. The proposed method has high potential for use as a sensitive method for determination of pyrethroid residues in water and vegetable samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Dose-response relationship of an environmental mixture of pyrethroids following an acute oral administration in the rat

    Science.gov (United States)

    Dose-response relationship of an environmental mixture of pyrethroids following an acute oral administration in the rat M.F. Hughes1, D.G. Ross1, J.M. Starr1, E.J. Scollon1,2, M.J. Wolansky1,3, K.M. Crofton1, M.J. DeVito1,4 1U.S. EPA, ORD, Research Triangle Park, NC, 2U.S. EPA,...

  3. Anopheles darlingi and Anopheles marajoara (Diptera: Culicidae) susceptibility to pyrethroids in an endemic area of the Brazilian Amazon

    OpenAIRE

    Galardo, Allan Kardec Ribeiro; Póvoa, Marinete Marins; Sucupira, Izis Monica Carvalho; Galardo, Clícia Denis; Santos, Roseli La Corte dos

    2015-01-01

    Abstract: INTRODUCTION: This study aimed to evaluate the susceptibility of Anopheles darlingi Root (1926) and Anopheles marajoara Galvão & Damasceno (1942) to pyrethroids used by the National Malaria Control Program in Brazil. METHODS: Mosquitoes from Amapá, Brazilian Amazon, were assessed for resistance to cypermethrin, deltamethrin, and alpha-cypermethrin. Insecticide-impregnated bottles were used as suggested by the CDC/Atlanta. RESULTS: Diagnostic dose for Anopheles darlingi was 12.5µg...

  4. Leg loss in Lutzomyia longipalpis (Diptera: Psychodidae) due to pyrethroid exposure: Toxic effect or defense by autotomy?

    Science.gov (United States)

    Santamaría, E; Cabrera, O L; Avendaño, J; Pardo, R H

    2016-01-01

    Phlebotomine sandflies lose their legs after exposure to pyrethroids. In some insects leg loss helps to defend them from intoxication and predation, a phenomenon known as autotomy. A field observation has shown that sandflies that have lost some legs are still able to blood-feed. The aims of the study were to determine whether leg loss in sandflies, after exposure to deltamethrin, is due to autotomy and to establish the effect of the leg loss on blood-feeding. Two experiments were carried out with Lutzomyia longipalpis: (i) Females were individually exposed to a sublethal time of deltamethrin and mortality and the number of leg loss were recorded; and (ii) Groups of females with complete legs or with 1-3 legs lost due to pyrethroid exposure were offered a blood meal and percentages of blood-fed and fully-fed females were recorded. Most females lost a median of 1 leg within 1-48 h post-exposure to deltamethrin. Mortality (after 24 h) was significantly higher for exposed females with lost legs (31.1%), compared to exposed females with complete legs (7.3%), and there were no differences in mortality between females with complete legs and the control (unexposed females). There were no differences between the three treatments in the percentages of blood-fed and fully-fed females. Leg loss in sandflies is a toxic effect of pyrethroids and there was no evidence of autotomy. The loss of up to three legs after exposure to pyrethroids does not affect blood-feeding behaviour in laboratory and probably also in wild conditions.

  5. Prey Foraging Under Sublethal Lambda-Cyhalothrin Exposure on Pyrethroid-Susceptible and -Resistant Lady Beetles (Eriopis connexa (Coleoptera: Coccinelidae)).

    Science.gov (United States)

    D'Ávila, V A; Reis, L C; Barbosa, W F; Cutler, G C; Torres, J B; Guedes, R N C

    2018-02-21

    Sublethal insecticide exposure may affect foraging of insects, including natural enemies, although the subject is usually neglected. The lady beetle Eriopis connexa (Germar, 1824) (Coleoptera: Coccinelidae) is an important predator of aphids with existing pyrethroid-resistant populations that are undergoing scrutiny for potential use in pest management systems characterized by frequent insecticide use. However, the potential effect of sublethal pyrethroid exposure on this predator's foraging activity has not yet been assessed and may compromise its use in biological control. Therefore, our objective was to assess the effect of sublethal lambda-cyhalothrin exposure on three components of the prey foraging activity (i.e., walking, and prey searching and handling), in both pyrethroid-susceptible and -resistant adults of E. connexa. Both lady beetle populations exhibited similar walking patterns without insecticide exposure in noncontaminated arenas, but in partially contaminated arenas walking differed between strains, such that the resistant insects exhibited greater walking activity. Behavioral avoidance expressed as repellence to lambda-cyhalothrin was not observed for either the susceptible or resistant populations of E. connexa, but the insecticide caused avoidance by means of inducing irritability in 40% of the individuals, irrespective of the strain. Insects remained in the insecticide-contaminated portion of the arena for extended periods resulting in greater exposure. Although lambda-cyhalothrin exposure did not affect prey searching by susceptible lady beetles, prey searching was extended for exposed resistant predators. In contrast, prey handling was not affected by population or by lambda-cyhalothrin exposure. Thus, sublethal exposure to the insecticide in conjunction with the insect resistance profile can affect prey foraging with pyrethroid-exposed resistant predators exhibiting longer prey searching time associated with higher walking activity reducing

  6. Pyrethroids and Nectar Toxins Have Subtle Effects on the Motor Function, Grooming and Wing Fanning Behaviour of Honeybees (Apis mellifera).

    Science.gov (United States)

    Oliver, Caitlin J; Softley, Samantha; Williamson, Sally M; Stevenson, Philip C; Wright, Geraldine A

    2015-01-01

    Sodium channels, found ubiquitously in animal muscle cells and neurons, are one of the main target sites of many naturally-occurring, insecticidal plant compounds and agricultural pesticides. Pyrethroids, derived from compounds found only in the Asteraceae, are particularly toxic to insects and have been successfully used as pesticides including on flowering crops that are visited by pollinators. Pyrethrins, from which they were derived, occur naturally in the nectar of some flowering plant species. We know relatively little about how such compounds--i.e., compounds that target sodium channels--influence pollinators at low or sub-lethal doses. Here, we exposed individual adult forager honeybees to several compounds that bind to sodium channels to identify whether these compounds affect motor function. Using an assay previously developed to identify the effect of drugs and toxins on individual bees, we investigated how acute exposure to 10 ng doses (1 ppm) of the pyrethroid insecticides (cyfluthrin, tau-fluvalinate, allethrin and permethrin) and the nectar toxins (aconitine and grayanotoxin I) affected honeybee locomotion, grooming and wing fanning behaviour. Bees exposed to these compounds spent more time upside down and fanning their wings. They also had longer bouts of standing still. Bees exposed to the nectar toxin, aconitine, and the pyrethroid, allethrin, also spent less time grooming their antennae. We also found that the concentration of the nectar toxin, grayanotoxin I (GTX), fed to bees affected the time spent upside down (i.e., failure to perform the righting reflex). Our data show that low doses of pyrethroids and other nectar toxins that target sodium channels mainly influence motor function through their effect on the righting reflex of adult worker honeybees.

  7. Synthetic Aperture Compound Imaging

    DEFF Research Database (Denmark)

    Hansen, Jens Munk

    Medical ultrasound imaging is used for many purposes, e.g. for localizing and classifying cysts, lesions, and other processes. Almost any mass is first observed using B-mode imaging and later classified using e.g. color flow, strain, or attenuation imaging. It is therefore important that the B......, it is demonstrated through theoretical considerations that the compound effect achieved is close to a theoretical maximum for the amount of compounding attainable and using a -pitch convex array transducer, the first in-vivo images are created. The computational demands for an implementation are massive...... and the limiting factor is the amount of memory IO resources available. An equally high demand for memory throughput is found in the computer gaming industry, where a large part of the processing takes place on the graphics processing unit (GPU). Using the GPU, a framework for synthetic aperture imaging...

  8. Transionospheric synthetic aperture imaging

    CERN Document Server

    Gilman, Mikhail; Tsynkov, Semyon

    2017-01-01

    This landmark monograph presents the most recent mathematical developments in the analysis of ionospheric distortions of SAR images and offers innovative new strategies for their mitigation. As a prerequisite to addressing these topics, the book also discusses the radar ambiguity theory as it applies to synthetic aperture imaging and the propagation of radio waves through the ionospheric plasma, including the anisotropic and turbulent cases. In addition, it covers a host of related subjects, such as the mathematical modeling of extended radar targets (as opposed to point-wise targets) and the scattering of radio waves off those targets, as well as the theoretical analysis of the start-stop approximation, which is used routinely in SAR signal processing but often without proper justification. The mathematics in this volume is clean and rigorous – no assumptions are hidden or ambiguously stated. The resulting work is truly interdisciplinary, providing both a comprehensive and thorough exposition of the field,...

  9. Synthetic antibiofilm peptides.

    Science.gov (United States)

    de la Fuente-Núñez, César; Cardoso, Marlon Henrique; de Souza Cândido, Elizabete; Franco, Octavio Luiz; Hancock, Robert E W

    2016-05-01

    Bacteria predominantly exist as multicellular aggregates known as biofilms that are associated with at least two thirds of all infections and exhibit increased adaptive resistance to conventional antibiotic therapies. Therefore, biofilms are major contributors to the global health problem of antibiotic resistance, and novel approaches to counter them are urgently needed. Small molecules of the innate immune system called host defense peptides (HDPs) have emerged as promising templates for the design of potent, broad-spectrum antibiofilm agents. Here, we review recent developments in the new field of synthetic antibiofilm peptides, including mechanistic insights, synergistic interactions with available antibiotics, and their potential as novel antimicrobials against persistent infections caused by biofilms. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Biodegradation of type II pyrethroids and major degraded products by a newly isolated Acinetobacter sp. strain JN8.

    Science.gov (United States)

    Jin, Zhaoxia; Guo, Qiong; Zhang, Zongshen; Yan, Tongshuai

    2014-08-01

    A Gram-negative aerobic bacterium, designated as JN8, was isolated from activated sludge and soil in a pesticides factory in China. It was found that JN8 had a high capacity for degrading a broad range of type II pyrethroids and utilizing these pyrethroids as the sole carbon source for cell growth. The degradation rates of a 100 mg·L(-1) concentration of β-cypermethrin, cypermethrin, fenpropathrin, fenvalerate, and deltamethrin by JN8 in mineral salt medium were 74.1%, 64.9%, 57.9%, 48.1% and 34.9%, respectively. Strain JN8 was identified as a species of Acinetobacter based on its biochemical properties and 16S rRNA sequence analysis. β-Cypermethrin was degraded by JN8 through hydrolysis of the carboxylester linkage to form 3-phenoxybenzoic acid and 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid, both of which could be further degraded by JN8. JN8 is the first strain of an Acinetobacter species in which pyrethoid-degrading activity has been detected, and such a feature makes it a potential resource for disposal of waste and effluent from pyrethroid manufacturing facilities.

  11. Pyrethroids, pyrethrins, and piperonyl butoxide in sediments by high-resolution gas chromatography/high-resolution mass spectrometry.

    Science.gov (United States)

    Woudneh, Million B; Oros, Daniel R

    2006-11-24

    A new method for determination of pyrethroids, pyrethrins, and piperonyl butoxide (PBO) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was developed for aquatic sediments. The method detection limits for pyrethroids (15 compounds), pyrethrins, and PBO ranged from 0.16 to 1.50 ng/g sediment, which was suitable for detecting these chemicals at environmentally relevant concentrations (low ng/L range) that are toxicologically significant to benthic organisms. Recovery of the analytes from a low level spiked sediment ranged from 89.7% to 135%. Resmethrin showed the lowest recovery at 23.5% and pyrethrins showed the highest recovery at 154%. To confirm the utility of this new method for environmental applications, sediment samples collected from five tributaries of the San Francisco Bay, California were analyzed. Individual pyrethroids were detected in concentrations of up to 17.6 ng/g, while PBO was detected in all sediment samples in concentrations of 0.010-0.215 ng/g. Pyrethrins were not found in the sediment samples.

  12. Toxicity of pyrethroids and repellency of diethyltoluamide in two deltamethrin-resistant colonies of Triatoma infestans Klug, 1834 (Hemiptera: Reduviidae

    Directory of Open Access Journals (Sweden)

    Valeria Sfara

    2006-02-01

    Full Text Available The aim of the currrent investigation was to evaluate (a the toxicity of three pyrethroids (deltamethrin, lambda-cyhalothrin, and tetramethrin; (b the effect of these insecticides on the locomotor activity; and (c the repellent effect of N,N-diethyl-m-toluamide (DEET on two deltamethrin-resistant strains of Triatoma infestans from Argentina (El Chorro and La Toma, and one susceptible strain. The resistance ratios (RRs obtained for the La Toma strain were: > 10,769, 50.7, and > 5.2 for deltamethrin, lambda-cyhalothrin, and tetramethrin respectively. The RRs for the El Chorro strain were: > 10,769, 85.8, and > 5.2 for deltamethrin, lambda-cyhalothrin, and tetramethrin respectively. The hyperactivity usually caused by the three pyrethroids was in both the deltamethrin-resistant strains compared to the susceptible reference strain. No differences were observed in the repellent effect of DEET between the three groups. These results indicate that the deltamethrin-resistant insects have a cross resistance to lambda-cyhalothrin and tetramethrin, and are also resistant to the first symptom of pyrethroid poisoning (hyperactivity. However, the sensorial process related to DEET repellency does not appear to be altered.

  13. Challenges for malaria elimination in Zanzibar: pyrethroid resistance in malaria vectors and poor performance of long-lasting insecticide nets.

    Science.gov (United States)

    Haji, Khamis A; Khatib, Bakari O; Smith, Stephen; Ali, Abdullah S; Devine, Gregor J; Coetzee, Maureen; Majambere, Silas

    2013-03-28

    Long-lasting insecticide treated nets (LLINs) and indoor residual house spraying (IRS) are the main interventions for the control of malaria vectors in Zanzibar. The aim of the present study was to assess the susceptibility status of malaria vectors against the insecticides used for LLINs and IRS and to determine the durability and efficacy of LLINs on the island. Mosquitoes were sampled from Pemba and Unguja islands in 2010-2011 for use in WHO susceptibility tests. One hundred and fifty LLINs were collected from households on Unguja, their physical state was recorded and then tested for efficacy as well as total insecticide content. Species identification revealed that over 90% of the Anopheles gambiae complex was An. arabiensis with a small number of An. gambiae s.s. and An. merus being present. Susceptibility tests showed that An. arabiensis on Pemba was resistant to the pyrethroids used for LLINs and IRS. Mosquitoes from Unguja Island, however, were fully susceptible to all pyrethroids tested. A physical examination of 150 LLINs showed that two thirds were damaged after only three years in use. All used nets had a significantly lower (p Zanzibar is seriously threatened by the resistance of malaria vectors to pyrethroids and the short-lived efficacy of LLINs. This study has revealed that even in relatively well-resourced and logistically manageable places like Zanzibar, malaria elimination is going to be difficult to achieve with the current control measures.

  14. Detection of target site resistance to pyrethroids and organophosphates in the horn fly using multiplex polymerase chain reaction.

    Science.gov (United States)

    Foil, L D; Guerrero, F D; Bendele, K G

    2010-09-01

    The horn fly, Haematobia irritans L., is an obligate blood-feeding fly and the primary insect pest parasitizing cattle in the United States. Pesticide resistance has become a substantial problem for cattle producers, and although several mechanisms of resistance are possible, target site resistance is the most important mechanism preventing control of this fly in the United States and possibly other countries. We developed a multiplex polymerase chain reaction assay to detect the known target site, pyrethroid resistance-associated mutation in the horn fly and a recently reported G262A mutation in the horn fly acetylcholinesterase, the target site for organophosphates. As expected, the pyrethroid resistance target site mutation was found in fly populations from Texas, Louisiana, Washington, Georgia, Mexico, and Brazil. This mutation was found to have a gender bias as it was more prevalent in females than males. The G262A acetylcholinesterase mutation was found in Texas, Louisiana, Washington, Georgia, and Mexico, but not Brazil. There was no gender bias in the occurrence of this mutation, and there was no correlation between the occurrence of the kdr and the G262A mutations. Unlike the case with the pyrethroid target site mutation, the presence of G262A did not appear to exclusively provide the level of resistance required to account for bioassay results. It is likely an additional mutation(s) occurs in the target site and/or a metabolic resistance mechanism exists in organophosphate-resistant horn fly populations.

  15. Density shift, morphological damage, lysosomal fragility and apoptosis of hemocytes of Indian molluscs exposed to pyrethroid pesticides.

    Science.gov (United States)

    Ray, Mitali; Bhunia, Anindya Sundar; Bhunia, Niladri Sekhar; Ray, Sajal

    2013-08-01

    Bellamya bengalensis (Gastropoda: Prosobranchia) and Lamellidens marginalis (Bivalvia: Eulamellibranchiata) are the molluscs of Indian freshwater ecosystem and important biological resources. These edible species bear economical, ecological, nutritional and medicinal importance. Natural habitat of these organisms is under the ecological threat of contamination by cypermethrin and fenvalerate, the common pyrethroid pesticides of India. Hemocytes are chief immunoeffector cells of molluscs which exhibit responsiveness against environmental toxins and perform diverse immunological functions including phagocytosis, encapsulation and cytotoxicity. Experimental exposure of cypermethrin and fenvalerate resulted in significant shift in density and morphological damage in hemocytes of B. bengalensis and L. marginalis respectively. Pyrethroid induced fragility and destabilization of hemocyte lysosomal membrane was recorded and proposed as an indication of toxin induced stress in molluscs. Apoptosis is an immunologically important cellular response which is modulated by environmental toxins. Pyrethroid exposure suppressed the physiological level of apoptosis and necrosis in hemocytes of B. bengalensis and L. marginalis indicating possible impairment of apoptosis mediated immunoprotection. Differential responses of B. bengalensis and L. marginalis hemocytes may be due to species specificity, toxin specificity, nonidentical immune strategies of Gastropoda and Bivalvia, specific habitat preference and related ecological niches. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Mosquito nets treated with a mixture of chlorfenapyr and alphacypermethrin control pyrethroid resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes in West Africa.

    Science.gov (United States)

    N'Guessan, Raphael; Ngufor, Corine; Kudom, Andreas A; Boko, Pelagie; Odjo, Abibathou; Malone, David; Rowland, Mark

    2014-01-01

    The effectiveness of insecticide treated nets is under threat across Africa south of the Sahara from the selection of pyrethroid resistance in Anopheles gambiae mosquitoes. To maintain progress against malaria it is necessary to identify alternative residual insecticides for mosquito nets. Mixtures of pyrethroid and insecticides with novel mode of action provide scope for both improved control and management of resistance through concurrent exposure to unrelated insecticides. The pyrrole chlorfenapyr and the pyrethroid alphacypermethrin were tested individually and as a mixture on mosquito nets in an experimental hut trial in southern Benin against pyrethroid resistant An gambiae and Culex quinquefasciatus mosquitoes. The nets were deliberately holed to simulate the effect of wear and tear. The nets treated with the mixture of chlorfenapyr 200 mg/m² and alphacypermethrin 25 mg/m² killed a proportion of An gambiae (77%, 95%CI: 66-86%) significantly greater than nets treated with alphacypermethrin 25 mg/m(2) (30%, 95%CI: 21-41%) but not significantly different from nets treated with chlorfenapyr 200 mg/m² (69%, 95%CI: 57-78%). The nets treated with the mixtures procured personal protection against An gambiae biting(58-62%) by a greater margin than the alphacypermethrin treated net (39%), whereas the chlorfenapyr treated net was not protective. A similar trend in mortality and blood feeding inhibition between treatments was observed in Cx quinquefasciatus to that seen in An. gambiae, although the effects were lower. A mixture of alphacypermethrin with chlorfenapyr applied at 100 mg/m² had an effect similar to the mixture with chlorfenapyr at 200 mg/m². The effectiveness of ITNs against pyrethroid resistant mosquitoes was restored by the mixture: the alphacypermethrin component reduced human-vector contact while the chlorfenapyr controlled pyrethroid-resistant mosquitoes. The complementary action of these unrelated insecticides demonstrates that the combination on

  17. Multimodal pyrethroid resistance in malaria vectors, Anopheles gambiae s.s., Anopheles arabiensis, and Anopheles funestus s.s. in western Kenya.

    Directory of Open Access Journals (Sweden)

    Hitoshi Kawada

    Full Text Available Anopheles gambiae s.s., Anopheles arabiensis, and Anopheles funestus s.s. are the most important species for malaria transmission. Pyrethroid resistance of these vector mosquitoes is one of the main obstacles against effective vector control. The objective of the present study was to monitor the pyrethroid susceptibility in the 3 major malaria vectors in a highly malaria endemic area in western Kenya and to elucidate the mechanisms of pyrethroid resistance in these species. Gembe East and West, Mbita Division, and 4 main western islands in the Suba district of the Nyanza province in western Kenya were used as the study area. Larval and adult collection and bioassay were conducted, as well as the detection of point mutation in the voltage-gated sodium channel (1014L by using direct DNA sequencing. A high level of pyrethroid resistance caused by the high frequency of point mutations (L1014S was detected in An. gambiae s.s. In contrast, P450-related pyrethroid resistance seemed to be widespread in both An. arabiensis and An. funestus s.s. Not a single L1014S mutation was detected in these 2 species. A lack of cross-resistance between DDT and permethrin was also found in An. arabiensis and An. funestus s.s., while An. gambiae s.s. was resistant to both insecticides. It is noteworthy that the above species in the same area are found to be resistant to pyrethroids by their unique resistance mechanisms. Furthermore, it is interesting that 2 different resistance mechanisms have developed in the 2 sibling species in the same area individually. The cross resistance between permethrin and DDT in An. gambiae s.s. may be attributed to the high frequency of kdr mutation, which might be selected by the frequent exposure to ITNs. Similarly, the metabolic pyrethroid resistance in An. arabiensis and An. funestus s.s. is thought to develop without strong selection by DDT.

  18. Synthetic biology and metabolic engineering.

    Science.gov (United States)

    Stephanopoulos, Gregory

    2012-11-16

    Metabolic engineering emerged 20 years ago as the discipline occupied with the directed modification of metabolic pathways for the microbial synthesis of various products. As such, it deals with the engineering (design, construction, and optimization) of native as well as non-natural routes of product synthesis, aided in this task by the availability of synthetic DNA, the core enabling technology of synthetic biology. The two fields, however, only partially overlap in their interest in pathway engineering. While fabrication of biobricks, synthetic cells, genetic circuits, and nonlinear cell dynamics, along with pathway engineering, have occupied researchers in the field of synthetic biology, the sum total of these areas does not constitute a coherent definition of synthetic biology with a distinct intellectual foundation and well-defined areas of application. This paper reviews the origins of the two fields and advances two distinct paradigms for each of them: that of unit operations for metabolic engineering and electronic circuits for synthetic biology. In this context, metabolic engineering is about engineering cell factories for the biological manufacturing of chemical and pharmaceutical products, whereas the main focus of synthetic biology is fundamental biological research facilitated by the use of synthetic DNA and genetic circuits.

  19. Synthetic cannabinoids: new matrix addiction

    Directory of Open Access Journals (Sweden)

    Antsyborov A.V.

    2017-04-01

    Full Text Available the majority of synthetic cannabinoids (SC, belongs to the group of so-called designer drugs distributed through illegal online shopping. The first reports of this group of psychoactive substances appeared in the 70s of the last century. Today, according to various estimates, there are over 160 varieties of synthetic cannabinoids, and this figure is increasing annually due to the synthesis of new substances in the group. This group of substances is designed to «copy» the psychoactive effects of cannabis. Initially, these substances were created solely for research purposes, to study the endocannabinoid system of the person. Natural THC is a partial agonist of cannabinoid receptors. Synthetic cannabinoids are full agonists CB1R and CB2R types of cannabinoid receptors. Most countries in the world, including Russia, at the legislative level have taken restrictive measures for preventing the spread of this group of substances. In order to circumvent the legislative measures, the producers of synthetic cannabinoids regularly changing the chemical formula. Each year, an increasing number of emergency hospital admissions associated with the use of synthetic cannabinoids in the peer-reviewed literature describes the deaths directly attributable to medical complications after taking synthetic cannabinoids. Numerous studies have proven the possibility of developing psychological dependence due to the use of synthetic cannabinoids. The proposed review of the literature is presented for the purpose of organizing data in the field of synthetic cannabinoids.

  20. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    N.D. Zegers (Netty)

    1995-01-01

    textabstractSynthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps

  1. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    Zegers, N.D.

    1995-01-01

    Synthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps that lead to the

  2. Imaging with Synthetic Aperture Radar

    CERN Document Server

    Massonnet, Didier

    2008-01-01

    Describing a field that has been transformed by the recent availability of data from a new generation of space and airborne systems, the authors offer a synthetic geometrical approach to the description of synthetic aperture radar, one that addresses physicists, radar specialists, as well as experts in image processing.  

  3. Synthetic biology of polyketide synthases

    DEFF Research Database (Denmark)

    Yuzawa, Satoshi; Backman, Tyler W.H.; Keasling, Jay D.

    2018-01-01

    ). The modules are composed of enzymatic domains that share sequence and functional similarity across all known PKSs. We have used the nomenclature of synthetic biology to classify the enzymatic domains and modules as parts and devices, respectively, and have generated detailed lists of both. In addition, we...... realize the potential that synthetic biology approaches bring to this class of molecules....

  4. Habitat productivity and pyrethroid susceptibility status of Aedes aegypti mosquitoes in Dar es Salaam, Tanzania.

    Science.gov (United States)

    Mathias, Leah; Baraka, Vito; Philbert, Anitha; Innocent, Ester; Francis, Filbert; Nkwengulila, Gamba; Kweka, Eliningaya J

    2017-06-09

    Aedes aegypti (Diptera: Culicidae) is the main vector of the dengue virus globally. Dengue vector control is mainly based on reducing the vector population through interventions, which target potential breeding sites. However, in Tanzania, little is known about this vector's habitat productivity and insecticide susceptibility status to support evidence-based implementation of control measures. The present study aimed at assessing the productivity and susceptibility status of A. aegypti mosquitoes to pyrethroid-based insecticides in Dar es Salaam, Tanzania. An entomological assessment was conducted between January and July 2015 in six randomly selected wards in Dar es Salaam, Tanzania. Habitat productivity was determined by the number of female adult A. aegypti mosquitoes emerged per square metre. The susceptibility status of adult A. aegypti females after exposure to 0.05% deltamethrin, 0.75% permethrin and 0.05% lambda-cyhalothrin was evaluated using the standard WHO protocols. Mortality rates were recorded after 24 h exposure and the knockdown effect was recorded at the time points of 10, 15, 20, 30, 40, 50 and 60 min to calculate the median knockdown times (KDT 50 and KDT 95 ). The results suggest that disposed tyres had the highest productivity, while water storage tanks had the lowest productivity among the breeding habitats Of A. aegypti mosquitoes. All sites demonstrated reduced susceptibility to deltamethrin (0.05%) within 24 h post exposure, with mortalities ranging from 86.3 ± 1.9 (mean ± SD) to 96.8 ± 0.9 (mean ± SD). The lowest and highest susceptibilities were recorded in Mikocheni and Sinza wards, respectively. Similarly, all sites demonstrated reduced susceptibility permethrin (0.75%) ranging from 83.1 ± 2.1% (mean ± SD) to 96.2 ± 0.9% (mean ± SD), in Kipawa and Sinza, respectively. Relatively low mortality rates were observed in relation to lambda-cyhalothrin (0.05%) at all sites, ranging from 83.1 ± 0

  5. Conflict of interest: use of pyrethroids and amidines against tsetse and ticks in zoonotic sleeping sickness endemic areas of Uganda.

    Science.gov (United States)

    Bardosh, Kevin; Waiswa, Charles; Welburn, Susan C

    2013-07-10

    Caused by trypanosomes and transmitted by tsetse flies, Human African Trypanosomiasis and bovine trypanosomiasis remain endemic across much of rural Uganda where the major reservoir of acute human infection is cattle. Following elimination of trypanosomes by mass trypanocidal treatment, it is crucial that farmers regularly apply pyrethroid-based insecticides to cattle to sustain parasite reductions, which also protect against tick-borne diseases. The private veterinary market is divided between products only effective against ticks (amidines) and those effective against both ticks and tsetse (pyrethroids). This study explored insecticide sales, demand and use in four districts of Uganda where mass cattle treatments have been undertaken by the 'Stamp Out Sleeping Sickness' programme. A mixed-methods study was undertaken in Dokolo, Kaberamaido, Serere and Soroti districts of Uganda between September 2011 and February 2012. This included: focus groups in 40 villages, a livestock keeper survey (n = 495), a veterinary drug shop questionnaire (n = 74), participatory methods in six villages and numerous semi-structured interviews. Although 70.5% of livestock keepers reportedly used insecticide each month during the rainy season, due to a variety of perceptions and practices nearly half used products only effective against ticks and not tsetse. Between 640 and 740 litres of insecticide were being sold monthly, covering an average of 53.7 cattle/km(2). Sales were roughly divided between seven pyrethroid-based products and five products only effective against ticks. In the high-risk HAT district of Kaberamaido, almost double the volume of non-tsetse effective insecticide was being sold. Factors influencing insecticide choice included: disease knowledge, brand recognition, product price, half-life and mode of product action, product availability, and dissemination of information. Stakeholders considered market restriction of non-tsetse effective products the most

  6. Investigating the molecular mechanisms of organophosphate and pyrethroid resistance in the fall armyworm Spodoptera frugiperda.

    Directory of Open Access Journals (Sweden)

    Renato A Carvalho

    Full Text Available The fall armyworm Spodoptera frugiperda is an economically important pest of small grain crops that occurs in all maize growing regions of the Americas. The intensive use of chemical pesticides for its control has led to the selection of resistant populations, however, to date, the molecular mechanisms underlying resistance have not been characterised. In this study the mechanisms involved in the resistance of two S. frugiperda strains collected in Brazil to chlorpyrifos (OP strain or lambda-cyhalothrin (PYR strain were investigated using molecular and genomic approaches. To examine the possible role of target-site insensitivity the genes encoding the organophosphate (acetylcholinesterase, AChE and pyrethroid (voltage-gated sodium channel, VGSC target-site proteins were PCR amplified. Sequencing of the S. frugiperda ace-1 gene identified several nucleotide changes in the OP strain when compared to a susceptible reference strain (SUS. These result in three amino acid substitutions, A201S, G227A and F290V, that have all been shown previously to confer organophosphate resistance in several other insect species. Sequencing of the gene encoding the VGSC in the PYR strain, identified mutations that result in three amino acid substitutions, T929I, L932F and L1014F, all of which have been shown previously to confer knockdown/super knockdown-type resistance in several arthropod species. To investigate the possible role of metabolic detoxification in the resistant phenotype of the OP and PYR stains all EST sequences available for S. frugiperda were used to design a gene-expression microarray. This was then used to compare gene expression in the resistant strains with the susceptible reference strain. Members of several gene families, previously implicated in metabolic resistance in other insects were found to be overexpressed in the resistant strains including glutathione S-transferases, cytochrome P450s and carboxylesterases. Taken together these results

  7. IDENTIFIKASI MUTASI NOKTAH PADA” GEN VOLTAGE GATED SODIUM CHANNEL” Aedes aegypti RESISTEN TERHADAP INSEKTISIDA PYRETHROID DI SEMARANG JAWA TENGAH

    Directory of Open Access Journals (Sweden)

    Widiarti Widiarti

    2012-11-01

    Full Text Available Abstract The identification of a point mutation in voltage-gated sodium channel gene was conducted on the major of dengue vector Aedes aegypti from Simongan Village, Semarang Municypality Central Java, which occurred to be resistant toward malathion and cypermethrin base on WHO methodology standard (impregnated paper.  The objectives of this studi was to identify the point mutation on the codon 1014  of voltage gated sodium channel gene of Ae. aegypti mosquitoes which was associated  with the vector resistance of pyrethroid group. The detection of a point mutation of  voltage-gated sodium channel was conducted using DNA extraction and semi nested polymerase chain reaction (PCR amplification of the mosquitoes resistant strain. The susceptibility test (as a screening resistant phenotype showed that few samples of Ae. aegypti from Simongan Village, Semarang Municypality Central Java resistant to malathion 0,8 % ( organophosphate group and cypermethrin 0,25 % (pyrethroid group. The sequencing result showed that there has been a mutation from the leucine (TTA which turned to be phenylalanin (TTT (kdr-w type on the codon 1014 at the voltage gated sodium channel gene of Ae. aegypti mosquitoes from  Simongan Village, Semarang Municypality Central Java, which was associated with the pyrethroid insecticide resistance. There were 78 % mosquitoes which brought  mutation alel kdr-w type on the codon 1014 F. Therefore dengue vector control activities should not use any pyrethroid insecticide group. Key  Words :  Resistance,  Aedes   aegypti,  Voltage   Gated   Sodium  Channel    (VGSC,  Point  Mutation. Abstrak Identifikasi mutasi noktah pada  gen Voltage Gated Sodium Channel (VGSC telah dilakukan pada nyamuk Aedes aegypti dari Kelurahan Simongan Kota Semarang, yang telah resisten terhadap insektisida Malathion dan Cypermethrin pada screening susceptibility test (Standar WHO Impregnated paper. Tujuan penelitian adalah untuk mendeteksi

  8. Computing with synthetic protocells.

    Science.gov (United States)

    Courbet, Alexis; Molina, Franck; Amar, Patrick

    2015-09-01

    In this article we present a new kind of computing device that uses biochemical reactions networks as building blocks to implement logic gates. The architecture of a computing machine relies on these generic and composable building blocks, computation units, that can be used in multiple instances to perform complex boolean functions. Standard logical operations are implemented by biochemical networks, encapsulated and insulated within synthetic vesicles called protocells. These protocells are capable of exchanging energy and information with each other through transmembrane electron transfer. In the paradigm of computation we propose, protoputing, a machine can solve only one problem and therefore has to be built specifically. Thus, the programming phase in the standard computing paradigm is represented in our approach by the set of assembly instructions (specific attachments) that directs the wiring of the protocells that constitute the machine itself. To demonstrate the computing power of protocellular machines, we apply it to solve a NP-complete problem, known to be very demanding in computing power, the 3-SAT problem. We show how to program the assembly of a machine that can verify the satisfiability of a given boolean formula. Then we show how to use the massive parallelism of these machines to verify in less than 20 min all the valuations of the input variables and output a fluorescent signal when the formula is satisfiable or no signal at all otherwise.

  9. Synthetic biology: lessons from the history of synthetic organic chemistry.

    Science.gov (United States)

    Yeh, Brian J; Lim, Wendell A

    2007-09-01

    The mid-nineteenth century saw the development of a radical new direction in chemistry: instead of simply analyzing existing molecules, chemists began to synthesize them--including molecules that did not exist in nature. The combination of this new synthetic approach with more traditional analytical approaches revolutionized chemistry, leading to a deep understanding of the fundamental principles of chemical structure and reactivity and to the emergence of the modern pharmaceutical and chemical industries. The history of synthetic chemistry offers a possible roadmap for the development and impact of synthetic biology, a nascent field in which the goal is to build novel biological systems.

  10. A mutation (L1014F) in the voltage-gated sodium channel of the grain aphid, Sitobion avenae, is associated with resistance to pyrethroid insecticides.

    Science.gov (United States)

    Foster, Stephen P; Paul, Verity L; Slater, Russell; Warren, Anne; Denholm, Ian; Field, Linda M; Williamson, Martin S

    2014-08-01

    The grain aphid, Sitobion avenae Fabricius (Hemiptera: Aphididae), is an important pest of cereal crops. Pesticides are the main method for control but carry the risk of selecting for resistance. In response to reports of reduced efficacy of pyrethroid sprays applied to S. avenae, field samples were collected and screened for mutations in the voltage-gated sodium channel, the primary target site for pyrethroids. Aphid mobility and mortality to lambda-cyhalothrin were measured in coated glass vial bioassays. A single amino acid substitution (L1014F) was identified in the domain IIS6 segment of the sodium channel from the S. avenae samples exhibiting reduced pyrethroid efficacy. Bioassays on aphids heterozygous for the kdr mutation (SR) or homozygous for the wild-type allele (SS) showed that those carrying the mutation had significantly lower susceptibility to lambda-cyhalothrin. The L1014F (kdr) mutation, known to confer pyrethroid resistance in many insect pests, has been identified for the first time in S. avenae. Clonal lines heterozygous for the mutation showed 35-40-fold resistance to lambda-cyhalothrin in laboratory bioassays, consistent with the reported effect of this mutation on pyrethroid sensitivity in other aphid species. © 2013 Society of Chemical Industry.

  11. Measurement of pyrethroids and their environmental degradation products in fresh fruits and vegetables using a modification of the quick easy cheap effective rugged safe (QuEChERS) method

    Science.gov (United States)

    Pyrethroid insecticides are used extensively in agriculture, and they, as well as their environmental degradates, may remain as residues on foods such as fruits and vegetables. Since pyrethroid degradates can be identical to the urinary markers used in human biomonitoring, it is ...

  12. Spicing things up: synthetic cannabinoids.

    Science.gov (United States)

    Spaderna, Max; Addy, Peter H; D'Souza, Deepak Cyril

    2013-08-01

    Recently, products containing synthetic cannabinoids, collectively referred to as Spice, are increasingly being used recreationally. The availability, acute subjective effects-including self-reports posted on Erowid-laboratory detection, addictive potential, and regulatory challenges of the Spice phenomenon are reviewed. Spice is sold under the guise of potpourri or incense. Unlike delta-9-tetrahydrocannabinol, the synthetic cannabinoids present in Spice are high-potency, high-efficacy, cannabinoid receptor full agonists. Since standard urine toxicology does not test for the synthetic cannabinoids in Spice, it is often used by those who want to avoid detection of drug use. These compounds have not yet been subjected to rigorous testing in humans. Acute psychoactive effects include changes in mood, anxiety, perception, thinking, memory, and attention. Adverse effects include anxiety, agitation, panic, dysphoria, psychosis, and bizarre behavior. Psychosis outcomes associated with Spice provide additional data linking cannabinoids and psychosis. Adverse events necessitating intervention by Poison Control Centers, law enforcement, emergency responders, and hospitals are increasing. Despite statutes prohibiting the manufacture, distribution, and sale of Spice products, manufacturers are replacing banned compounds with newer synthetic cannabinoids that are not banned. There is an urgent need for better research on the effects of synthetic cannabinoids to help clinicians manage adverse events and to better understand cannabinoid pharmacology in humans. The reported psychosis outcomes associated with synthetic cannabinoids contribute to the ongoing debate on the association between cannabinoids and psychosis. Finally, drug detection tests for synthetic cannabinoids need to become clinically available.

  13. Synthetic Biology and Personalized Medicine

    Science.gov (United States)

    Jain, K.K.

    2013-01-01

    Synthetic biology, application of synthetic chemistry to biology, is a broad term that covers the engineering of biological systems with structures and functions not found in nature to process information, manipulate chemicals, produce energy, maintain cell environment and enhance human health. Synthetic biology devices contribute not only to improve our understanding of disease mechanisms, but also provide novel diagnostic tools. Methods based on synthetic biology enable the design of novel strategies for the treatment of cancer, immune diseases metabolic disorders and infectious diseases as well as the production of cheap drugs. The potential of synthetic genome, using an expanded genetic code that is designed for specific drug synthesis as well as delivery and activation of the drug in vivo by a pathological signal, was already pointed out during a lecture delivered at Kuwait University in 2005. Of two approaches to synthetic biology, top-down and bottom-up, the latter is more relevant to the development of personalized medicines as it provides more flexibility in constructing a partially synthetic cell from basic building blocks for a desired task. PMID:22907209

  14. Mechanisms of pyrethroid resistance inHaematobia irritans (Muscidae from Mato Grosso do Sul state, Brazil

    Directory of Open Access Journals (Sweden)

    Antonio Thadeu Medeiros Barros

    Full Text Available Horn fly resistance to pyrethroid insecticides occurs throughout Brazil, but knowledge about the involved mechanisms is still in an incipient stage. This survey was aimed to identify the mechanisms of horn fly resistance to cypermethrin in Mato Grosso do Sul state, Brazil. Impregnated filter paper bioassays using cypermethrin, synergized or not with piperonyl butoxide (PBO and triphenyl phosphate (TPP, were conducted from March 2004 to June 2005 in horn fly populations (n = 33 from all over the state. All populations were highly resistant to cypermethrin, with resistance factors (RF ranging from 89.4 to 1,020.6. Polymerase chain reaction (PCR assays to detect the knockdown resistance (kdr mutation also were performed in 16 samples. The kdr mutation was found in 75% of the tested populations, mostly with relatively low frequencies (<20%, and was absent in some highly resistant populations. Addition of TPP did not significantly reduce the LC50 in any population. However, PBO reduced LC50s above 40-fold in all tested populations, resulting in RFs ≤ 10 in most cases. Horn fly resistance to cypermethrin is widespread in the state, being primarily caused by an enhanced activity of P450 mono-oxygenases and secondarily by reduced target site sensitivity.

  15. Molecular diagnosis of pyrethroid resistance in Mexican strains of Boophilus microplus (Acari: Ixodidae).

    Science.gov (United States)

    Guerrero, Felix D; Li, Andrew Y; Hernandez, Ruben

    2002-09-01

    Polymerase chain reaction (PCR) diagnostic assays were used to identify possible resistance-associated roles of two amino acid substitutions found in pyrethroid resistance-associated genes of Boophilus microplus (Canestrini). Individual larvae from the San Felipe target site resistant strain and the Coatzacoalcos (Cz) metabolic resistant strain were separated into resistant and susceptible groups by larval packet bioassays and analyzed by PCR. A Phe --> Ile amino acid mutation in the sodium channel gene S6 transmembrane segment of domain III was found to have a close association with survival of acaricide treatments containing as high as 30% permethrin. As the permethrin dose was increased, an increase was seen in the proportion of surviving larvae that possessed two mutated sodium channel alleles. An Asp --> Asn amino acid substitution, originally found in high allele frequency in alleles of the CzEst9 esterase of the Cz strain, appeared to provide some resistance to permethrin. However, the presence of the mutation did not associate with resistance in the dose-response fashion seen with the sodium channel amino acid mutation. Resistance provided by CzEst9 might be more dependent on concentration of CzEst9 more so than the presence of a mutated allele.

  16. Development of apple certified reference material for quantification of organophosphorus and pyrethroid pesticides.

    Science.gov (United States)

    Otake, Takamitsu; Yarita, Takashi; Aoyagi, Yoshie; Kuroda, Youko; Numata, Masahiko; Iwata, Hitoshi; Watai, Masatoshi; Mitsuda, Hitoshi; Fujikawa, Takashi; Ota, Hidekazu

    2013-06-01

    An apple certified reference material for the analysis of pesticide residues was issued by the National Metrology Institute of Japan. Organophosphorus and pyrethroid pesticides were sprayed on apples, and these were used as raw materials of certified reference material. The harvested apples were cut into small pieces, freeze-dried, pulverized, sieved, placed into 200 brown glass bottles (3g each), and sterilized by γ-irradiation. Stability and homogeneity assessment was performed, and the relative uncertainties due to instability (for an expiry date of 32 months) and inhomogeneity were 10.3-25.0% and 4.0-6.8%, respectively. The characterization was carried out using multiple analytical methods to ensure the reliability of analytical results; the values of target pesticides were obtained by isotope dilution mass spectrometry. Certified values were 2.28 ± 0.82 mg/kg for diazinon, 3.14 ± 0.79 mg/kg for fenitrothion, 1.55 ± 0.81 mg/kg for cypermethrin, and 2.81 ± 0.70 mg/kg for permethrin. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Degradation of Organophosphorus and Pyrethroid Insecticides in Beverages: Implications for Risk Assessment

    Directory of Open Access Journals (Sweden)

    Samantha A. Radford

    2018-02-01

    Full Text Available Since urinary insecticide metabolites are commonly used as biomarkers of exposure, it is important that we quantify whether insecticides degrade in food and beverages in order to better perform risk assessment. This study was designed to quantify degradation of organophosphorus and pyrethroid insecticides in beverages. Purified water, white grape juice, orange juice, and red wine were fortified with 500 ng/mL diazinon, malathion, chlorpyrifos, permethrin, cyfluthrin, cypermethrin, and deltamethrin, and aliquots were extracted several times over a 15-day storage period at 2.5 °C. Overall, statistically significant loss of at least one insecticide was observed in each matrix, and at least five out of seven insecticides demonstrated a statistically significant loss in all matrices except orange juice. An investigation of an alternative mechanism of insecticide loss—adsorption onto the glass surface of the storage jars—was carried out, which indicated that this mechanism of loss is insignificant. Results of this work suggest that insecticides degrade in these beverages, and this degradation may lead to pre-existing insecticide degradates in the beverages, suggesting that caution should be exercised when using urinary insecticide metabolites to assess exposure and risk.

  18. Bistatic synthetic aperture radar

    Science.gov (United States)

    Yates, Gillian

    Synthetic aperture radar (SAR) allows all-weather, day and night, surface surveillance and has the ability to detect, classify and geolocate objects at long stand-off ranges. Bistatic SAR, where the transmitter and the receiver are on separate platforms, is seen as a potential means of countering the vulnerability of conventional monostatic SAR to electronic countermeasures, particularly directional jamming, and avoiding physical attack of the imaging platform. As the receiving platform can be totally passive, it does not advertise its position by RF emissions. The transmitter is not susceptible to jamming and can, for example, operate at long stand-off ranges to reduce its vulnerability to physical attack. This thesis examines some of the complications involved in producing high-resolution bistatic SAR imagery. The effect of bistatic operation on resolution is examined from a theoretical viewpoint and analytical expressions for resolution are developed. These expressions are verified by simulation work using a simple 'point by point' processor. This work is extended to look at using modern practical processing engines for bistatic geometries. Adaptations of the polar format algorithm and range migration algorithm are considered. The principal achievement of this work is a fully airborne demonstration of bistatic SAR. The route taken in reaching this is given, along with some results. The bistatic SAR imagery is analysed and compared to the monostatic imagery collected at the same time. Demonstrating high-resolution bistatic SAR imagery using two airborne platforms represents what I believe to be a European first and is likely to be the first time that this has been achieved outside the US (the UK has very little insight into US work on this topic). Bistatic target characteristics are examined through the use of simulations. This also compares bistatic imagery with monostatic and gives further insight into the utility of bistatic SAR.

  19. Synthetic biology for therapeutic applications.

    Science.gov (United States)

    Abil, Zhanar; Xiong, Xiong; Zhao, Huimin

    2015-02-02

    Synthetic biology is a relatively new field with the key aim of designing and constructing biological systems with novel functionalities. Today, synthetic biology devices are making their first steps in contributing new solutions to a number of biomedical challenges, such as emerging bacterial antibiotic resistance and cancer therapy. This review discusses some synthetic biology approaches and applications that were recently used in disease mechanism investigation and disease modeling, drug discovery and production, as well as vaccine development and treatment of infectious diseases, cancer, and metabolic disorders.

  20. The Ethics of Synthetic Biology

    DEFF Research Database (Denmark)

    Christiansen, Andreas

    The dissertation analyses and discusses a number of ethical issues that have been raised in connection with the development of synthetic biology. Synthetic biology is a set of new techniques for DNA-level design and construction of living beings with useful properties. The dissertation especially......) popular responsesto them succeed, and whether the objections are ultimately persuasive.2. Given that synthetic biology is a new technology, there is a certain degree of uncertainty about its ultimate effects, and many perceive the technology as risky. I discuss two common approaches in risk regulation...

  1. Tissue Harmonic Synthetic Aperture Imaging

    DEFF Research Database (Denmark)

    Rasmussen, Joachim

    The main purpose of this PhD project is to develop an ultrasonic method for tissue harmonic synthetic aperture imaging. The motivation is to advance the field of synthetic aperture imaging in ultrasound, which has shown great potentials in the clinic. Suggestions for synthetic aperture tissue...... system complexity compared to conventional synthetic aperture techniques. In this project, SASB is sought combined with a pulse inversion technique for 2nd harmonic tissue harmonic imaging. The advantages in tissue harmonic imaging (THI) are expected to further improve the image quality of SASB....... The first part of the scientific contribution investigates an implementation of pulse inversion for THI on the experimental ultrasound system SARUS. The technique is initially implemented for linear array transducers and then expanded for convex array transducers. The technique is evaluated based on spatial...

  2. Adaptive Synthetic Forces: Situation Awareness

    National Research Council Canada - National Science Library

    Hill, Randall

    2001-01-01

    ...: perception, comprehension, and prediction. Building on these ideas, we developed techniques for improving the situation awareness in synthetic helicopter pilots for the ModSAF military simulation by giving them more human-like perception...

  3. Designing synthetic networks in silico

    NARCIS (Netherlands)

    Smith, Robert W.; Sluijs, van Bob; Fleck, Christian

    2017-01-01

    Background: Evolution has led to the development of biological networks that are shaped by environmental signals. Elucidating, understanding and then reconstructing important network motifs is one of the principal aims of Systems & Synthetic Biology. Consequently, previous research has focused

  4. Synthetic Biology for Specialty Chemicals.

    Science.gov (United States)

    Markham, Kelly A; Alper, Hal S

    2015-01-01

    In this review, we address recent advances in the field of synthetic biology and describe how those tools have been applied to produce a wide variety of chemicals in microorganisms. Here we classify the expansion of the synthetic biology toolbox into three different categories based on their primary function in strain engineering-for design, for construction, and for optimization. Next, focusing on recent years, we look at how chemicals have been produced using these new synthetic biology tools. Advances in producing fuels are briefly described, followed by a more thorough treatment of commodity chemicals, specialty chemicals, pharmaceuticals, and nutraceuticals. Throughout this review, an emphasis is placed on how synthetic biology tools are applied to strain engineering. Finally, we discuss organism and host strain diversity and provide a future outlook in the field.

  5. Is synthetic biology mechanical biology?

    Science.gov (United States)

    Holm, Sune

    2015-12-01

    A widespread and influential characterization of synthetic biology emphasizes that synthetic biology is the application of engineering principles to living systems. Furthermore, there is a strong tendency to express the engineering approach to organisms in terms of what seems to be an ontological claim: organisms are machines. In the paper I investigate the ontological and heuristic significance of the machine analogy in synthetic biology. I argue that the use of the machine analogy and the aim of producing rationally designed organisms does not necessarily imply a commitment to mechanical biology. The ideal of applying engineering principles to biology is best understood as expressing recognition of the machine-unlikeness of natural organisms and the limits of human cognition. The paper suggests an interpretation of the identification of organisms with machines in synthetic biology according to which it expresses a strategy for representing, understanding, and constructing living systems that are more machine-like than natural organisms.

  6. Programming languages for synthetic biology.

    Science.gov (United States)

    Umesh, P; Naveen, F; Rao, Chanchala Uma Maheswara; Nair, Achuthsankar S

    2010-12-01

    In the backdrop of accelerated efforts for creating synthetic organisms, the nature and scope of an ideal programming language for scripting synthetic organism in-silico has been receiving increasing attention. A few programming languages for synthetic biology capable of defining, constructing, networking, editing and delivering genome scale models of cellular processes have been recently attempted. All these represent important points in a spectrum of possibilities. This paper introduces Kera, a state of the art programming language for synthetic biology which is arguably ahead of similar languages or tools such as GEC, Antimony and GenoCAD. Kera is a full-fledged object oriented programming language which is tempered by biopart rule library named Samhita which captures the knowledge regarding the interaction of genome components and catalytic molecules. Prominent feature of the language are demonstrated through a toy example and the road map for the future development of Kera is also presented.

  7. Developmental toxicity and neurotoxicity of synthetic organic insecticides in zebrafish (Danio rerio): A comparative study of deltamethrin, acephate, and thiamethoxam.

    Science.gov (United States)

    Liu, XingYu; Zhang, QiuPing; Li, ShiBao; Mi, Ping; Chen, DongYan; Zhao, Xin; Feng, XiZeng

    2018-05-01

    Synthetic organic insecticides, including pyrethroids, organophosphates, neonicotinoids and other types, have the potential to alter the ecosystems and many are harmful to humans. This study examines the developmental toxicity and neurotoxicity of three synthetic organic insecticides, including deltamethrin (DM), acephate (AP), and thiamethoxam (TM), using embryo-larval stages of zebrafish (Danio rerio). Results showed that DM exposure led to embryo development delay and a significant increase in embryo mortality at 24 and 48 h post-fertilization (hpf). DM and AP decreased embryo chorion surface tension at 24 hpf, along with the increase in hatching rate at 72 hpf. Moreover, DM caused ntl, shh, and krox20 misexpression in a dose-dependent manner with morphological deformities of shorter body length, smaller eyes, and larger head-body angles at 10 μg/L. TM did not show significant developmental toxicity. Furthermore, results of larval rest/wake assay indicated that DM (>0.1 μg/L) and AP (0.1 mg/L) increased activity behavior with different patterns. Interestingly, as an insect-specific pesticide, TM still could alter locomotor activity in zebrafish larvae at concentrations as low as 0.1 mg/L. Our results indicate that different types of synthetic organic insecticides could create different toxicity outcomes in zebrafish embryos and larvae. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Generating realistic synthetic meteoroid orbits

    Science.gov (United States)

    Vida, Denis; Brown, Peter G.; Campbell-Brown, Margaret

    2017-11-01

    Context. Generating a synthetic dataset of meteoroid orbits is a crucial step in analysing the probabilities of random grouping of meteoroid orbits in automated meteor shower surveys. Recent works have shown the importance of choosing a low similarity threshold value of meteoroid orbits, some pointing out that the recent meteor shower surveys produced false positives due to similarity thresholds which were too high. On the other hand, the methods of synthetic meteoroid orbit generation introduce additional biases into the data, thus making the final decision on an appropriate threshold value uncertain. Aims. As a part of the ongoing effort to determine the nature of meteor showers and improve automated methods, it was decided to tackle the problem of synthetic meteoroid orbit generation, the main goal being to reproduce the underlying structure and the statistics of the observed data in the synthetic orbits. Methods. A new method of generating synthetic meteoroid orbits using the Kernel Density Estimation method is presented. Several types of approaches are recommended, depending on whether one strives to preserve the data structure, the data statistics or to have a compromise between the two. Results. The improvements over the existing methods of synthetic orbit generation are demonstrated. The comparison between the previous and newly developed methods are given, as well as the visualization tools one can use to estimate the influence of different input parameters on the final data.

  9. Loss of protection with insecticide-treated nets against pyrethroid-resistant Culex quinquefasciatus mosquitoes once nets become holed: an experimental hut study

    Directory of Open Access Journals (Sweden)

    Irish SR

    2008-06-01

    Full Text Available Abstract Background An important advantage of pyrethroid-treated nets over untreated nets is that once nets become worn or holed a pyrethroid treatment will normally restore protection. The capacity of pyrethroids to kill or irritate any mosquito that comes into contact with the net and prevent penetration of holes or feeding through the sides are the main reasons why treated nets continue to provide protection despite their condition deteriorating over time. Pyrethroid resistance is a growing problem among Anopheline and Culicine mosquitoes in many parts of Africa. When mosquitoes become resistant the capacity of treated nets to provide protection might be diminished, particularly when holed. An experimental hut trial against pyrethroid-resistant Culex quinquefasciatus was therefore undertaken in southern Benin using a series of intact and holed nets, both untreated and treated, to assess any loss of protection as nets deteriorate with use and time. Results There was loss of protection when untreated nets became holed; the proportion of mosquitoes blood feeding increased from 36.2% when nets were intact to between 59.7% and 68.5% when nets were holed to differing extents. The proportion of mosquitoes blood feeding when treated nets were intact was 29.4% which increased to 43.6–57.4% when nets were holed. The greater the number of holes the greater the loss of protection regardless of whether nets were untreated or treated. Mosquito mortality in huts with untreated nets was 12.9–13.6%; treatment induced mortality was less than 12%. The exiting rate of mosquitoes into the verandas was higher in huts with intact nets. Conclusion As nets deteriorate with use and become increasingly holed the capacity of pyrethroid treatments to restore protection is greatly diminished against resistant Culex quinquefasciatus mosquitoes.

  10. Genome-wide and expression-profiling analyses suggest the main cytochrome P450 genes related to pyrethroid resistance in the malaria vector, Anopheles sinensis (Diptera Culicidae).

    Science.gov (United States)

    Yan, Zheng-Wen; He, Zheng-Bo; Yan, Zhen-Tian; Si, Feng-Ling; Zhou, Yong; Chen, Bin

    2018-02-02

    Anopheles sinensis is one of the major malaria vectors. However, pyrethroid resistance in An. sinensis is threatening malaria control. Cytochrome P450-mediated detoxification is an important pyrethroid resistance mechanism that has been unexplored in An. sinensis. In this study, we performed a comprehensive analysis of the An. sinensis P450 gene superfamily with special attention to their role in pyrethroid resistance using bioinformatics and molecular approaches. Our data revealed the presence of 112 individual P450 genes in An. sinensis, which were classified into four major clans (mitochondrial, CYP2, CYP3 and CYP4), 18 families and 50 subfamilies. Sixty-seven genes formed nine gene clusters, and genes within the same cluster and the same gene family had a similar gene structure. Phylogenetic analysis showed that most of An. sinensis P450s (82/112) had very close 1: 1 orthology with Anopheles gambiae P450s. Five genes (AsCYP6Z2, AsCYP6P3v1, AsCYP6P3v2, AsCYP9J5 and AsCYP306A1) were significantly upregulated in three pyrethroid-resistant populations in both RNA-seq and RT-qPCR analyses, suggesting that they could be the most important P450 genes involved in pyrethroid resistance in An. sinensis. Our study provides insight on the diversity of An. sinensis P450 superfamily and basis for further elucidating pyrethroid resistance mechanism in this mosquito species. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

  11. Pyrethroid resistance persists after ten years without usage against Aedes aegypti in governmental campaigns: Lessons from São Paulo State, Brazil.

    Science.gov (United States)

    Macoris, Maria de Lourdes; Martins, Ademir Jesus; Andrighetti, Maria Teresa Macoris; Lima, José Bento Pereira; Valle, Denise

    2018-03-01

    Aedes aegypti, vector of dengue, chikungunya and Zika viruses, is found at high densities in tropical urban areas. The dissemination of this vector is partially the consequence of failures in current vector control methods, still mainly relying upon insecticides. In the State of São Paulo (SP), Brazil, public health managers employed pyrethroids against Ae. aegypti adults from 1989 to 2000, when a robust insecticide resistance monitoring system detected resistance to pyrethroids in several Ae. aegypti populations. However, pyrethroids are also the preferred compounds engaged in household applications due to their rapid knockdown effect, lower toxicity to mammals and less irritating smell. We evaluated pyrethroid resistance in Ae. aegypti populations over the course of a decade, from 2004 to 2015, after interruption of pyrethroid public applications in SP. Qualitative bioassays with papers impregnated with a deltamethrin diagnostic dose (DD) performed with insects from seven SP municipalities and evaluated yearly from 2006 to 2014, detected resistance in most of the cases. Quantitative bioassays were also carried out with four populations in 2011, suggesting a positive correlation between resistance level and survivorship in the DD bioassays. Biochemical tests conducted with seven insect populations in 2006 and 2015, detected increasing metabolic alterations of all major classes of detoxifying enzymes, mostly of mixed function oxidases. Genotyping of the voltage-gated sodium channel (AaNaV, the pyrethroid target-site) with a TaqMan real time PCR based technique was performed from 2004 to 2014 in all seven localities. The two kdr mutations, Val1016Ile and Phe1534Cys, known to be spread throughout Brazil, were always present with a severe decrease of the susceptible allele over time. These results are discussed in the context of public and domestic insecticide use, the necessity of implementation of a strong integrated vector control strategy and the conceptual

  12. Kdr mutations in Triatoma infestans from the Gran Chaco are distributed in two differentiated foci: Implications for pyrethroid resistance management.

    Science.gov (United States)

    Sierra, Ivana; Capriotti, Natalia; Fronza, Georgina; Mougabure-Cueto, Gastón; Ons, Sheila

    2016-06-01

    Point mutations in the voltage-gated sodium channel, the primary target of pyrethroid insecticides, have been associated with the resistance in Triatoma infestans, an important vector of Chagas' disease. Hence, the sustainability of vector control programs requires the implementation of resistance management strategies. We determined the sensitivity of the molecular assays previously designed for early resistance detection to be used in pooled samples from a wide area of the endemic region, and validated them for their routine use in control campaigns for the monitoring of insecticide resistance in T. infestans. Consequently, we used these methods to examine the distribution of resistance-associated mutations in the sodium channel gene in populations of T. infestans from the Argentinean and Bolivian Gran Chaco. The PASA and REA assays tested proved sensitive enough to detect kdr SNPs in pooled samples, indicating these assays are suitable for routine screening in insecticide resistance surveillance. Two geographically differentiated foci were detected in T. infestans populations from the Argentinean and Bolivian Gran Chaco, with populations on the Bolivian-Argentinean border carrying L1014F mutation, and those from the Argentinean Chaco carrying L925I mutation. In all highly resistant populations analyzed, one of both kdr mutations was present, and toxicological assays determined that all pyrethroid resistant populations analyzed herein were sensitive to fenitrothion. The principal cause of pyrethroid resistance in T. infestans from the Gran Chaco ecoregion is kdr mutations in the sodium channel. Different levels of resistance occur in different populations carrying identical mutation, suggesting the existence of contributory mechanisms. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Analysing deltamethrin susceptibility and pyrethroid esterase activity variations in sylvatic and domestic Triatoma infestans at the embryonic stage

    Science.gov (United States)

    Santo-Orihuela, Pablo Luis; Carvajal, Guillermo; Picollo, María Inés; Vassena, Claudia Viviana

    2013-01-01

    The aim of the present work was to study the deltamethrin susceptibility of eggs from Triatoma infestans populations and the contribution of pyrethroid esterases to deltamethrin degradation. Insects were collected from sylvatic areas, including Veinte de Octubre and Kirus-Mayu (Bolivia) and from domiciliary areas, including El Palmar (Bolivia) and La Pista (Argentina). Deltamethrin susceptibility was determined by dose-response bioassays. Serial dilutions of deltamethrin (0.0005-1 mg/mL) were topically applied to 12-day-old eggs. Samples from El Palmar had the highest lethal dose ratio (LDR) value (44.90) compared to the susceptible reference strain (NFS), whereas the Veinte de Octubre samples had the lowest value (0.50). Pyrethroid esterases were evaluated using 7-coumaryl permethrate (7-CP) on individually homogenised eggs from each population and from NFS. The El Palmar and La Pista samples contained 40.11 and 36.64 pmol/min/mg protein, respectively, and these values were statistically similar to NFS (34.92 pmol/min/mg protein) and different from Kirus-Mayu and Veinte de Octubre (27.49 and 22.69 pmol/min/mg protein, respectively). The toxicological data indicate that the domestic populations were resistant to deltamethrin, but no statistical contribution of 7-CP esterases was observed. The sylvatic populations had similar LDR values to NFS, but lower 7-CP esterase activities. Moreover, this is the first study of the pyrethroid esterases on T. infestans eggs employing a specific substrate (7-CP). PMID:24402155

  14. Analysing deltamethrin susceptibility and pyrethroid esterase activity variations in sylvatic and domestic Triatoma infestans at the embryonic stage

    Directory of Open Access Journals (Sweden)

    Pablo Luis Santo-Orihuela

    2013-12-01

    Full Text Available The aim of the present work was to study the deltamethrin susceptibility of eggs from Triatoma infestans populations and the contribution of pyrethroid esterases to deltamethrin degradation. Insects were collected from sylvatic areas, including Veinte de Octubre and Kirus-Mayu (Bolivia and from domiciliary areas, including El Palmar (Bolivia and La Pista (Argentina. Deltamethrin susceptibility was determined by dose-response bioassays. Serial dilutions of deltamethrin (0.0005-1 mg/mL were topically applied to 12-day-old eggs. Samples from El Palmar had the highest lethal dose ratio (LDR value (44.90 compared to the susceptible reference strain (NFS, whereas the Veinte de Octubre samples had the lowest value (0.50. Pyrethroid esterases were evaluated using 7-coumaryl permethrate (7-CP on individually homogenised eggs from each population and from NFS. The El Palmar and La Pista samples contained 40.11 and 36.64 pmol/min/mg protein, respectively, and these values were statistically similar to NFS (34.92 pmol/min/mg protein and different from Kirus-Mayu and Veinte de Octubre (27.49 and 22.69 pmol/min/mg protein, respectively. The toxicological data indicate that the domestic populations were resistant to deltamethrin, but no statistical contribution of 7-CP esterases was observed. The sylvatic populations had similar LDR values to NFS, but lower 7-CP esterase activities. Moreover, this is the first study of the pyrethroid esterases on T. infestans eggs employing a specific substrate (7-CP.

  15. Assessment of complex water pollution with heavy metals and Pyrethroid pesticides on transcript levels of metallothionein and immune related genes.

    Science.gov (United States)

    Ghazy, Haneen A; Abdel-Razek, Mohamed A S; El Nahas, Abeer F; Mahmoud, Shawky

    2017-09-01

    Alteration of immunological function of an aquatic organism can be used as an indicator for evaluating the direct effect of exposure to pollutants. The aim of this work is to assess the impact of complex water pollution with special reference to Pyrethroid pesticides and heavy metals on mRNA transcript levels of Metallothionine and some immune related genes of Nile tilapia (Oreochromas Niloticus). Residues of six heavy metals and six Pyrethroid were assessed in water as well as fish tissues at three different sites of Lake Burullus, located at Northern Egypt. Variations of water physicochemical properties associated with different levels of heavy metals at the three different sections were recorded. Tissue residues of Fe, Mn and Zn, Cu, Ni exceed water levels in contrast to elevated water level of Pb. All assessed Pyrethroids are detected in fish tissue samples with higher concentration (3-42 folds) than that found in water samples especially Cypermethrin. Significant down-regulation of expression levels of metallothionein (MT) at the three sections of the lake was observed. The expression of immune related genes (IgM) and inflammatory cytokines (TNF, IL.8 and IL.1) were affected. IgM and TNF were significantly down-regulated at eastern and western section of the lake; meanwhile the expression of IL8 is down regulated at the three sections of the lack. IL1 was significantly up-regulated at eastern and middle sections. We conclude that, variable gene expression of MT and immune-related genes at the three sections of the lack impose different response to complex water pollution in relation to variable aquatic environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Freedom and Responsibility in Synthetic Genomics: The Synthetic Yeast Project.

    Science.gov (United States)

    Sliva, Anna; Yang, Huanming; Boeke, Jef D; Mathews, Debra J H

    2015-08-01

    First introduced in 2011, the Synthetic Yeast Genome (Sc2.0) PROJECT is a large international synthetic genomics project that will culminate in the first eukaryotic cell (Saccharomyces cerevisiae) with a fully synthetic genome. With collaborators from across the globe and from a range of institutions spanning from do-it-yourself biology (DIYbio) to commercial enterprises, it is important that all scientists working on this project are cognizant of the ethical and policy issues associated with this field of research and operate under a common set of principles. In this commentary, we survey the current ethics and regulatory landscape of synthetic biology and present the Sc2.0 Statement of Ethics and Governance to which all members of the project adhere. This statement focuses on four aspects of the Sc2.0 PROJECT: societal benefit, intellectual property, safety, and self-governance. We propose that such project-level agreements are an important, valuable, and flexible model of self-regulation for similar global, large-scale synthetic biology projects in order to maximize the benefits and minimize potential harms. Copyright © 2015 by the Genetics Society of America.

  17. 77 FR 56782 - Bifenthrin; Pesticide Tolerances

    Science.gov (United States)

    2012-09-14

    ... startle response was similar between adult and young rats. 3. Conclusion. Given different levels of...) of FFDCA defines ``safe'' to mean that ``there is a reasonable certainty that no harm will result... = 3x........ is an MOE = 100.. Occupational: Adults, LOC is an MOE = 100. Inhalation short-term (1 to...

  18. Comparison of the toxic effect of pyrethroids on [i]Ixodes ricinus[/i] and Dermacentor reticulatus females

    Directory of Open Access Journals (Sweden)

    Alicja Buczek

    2014-06-01

    Full Text Available introduction. Despite the increased rates of infestations with[i] I. ricinus (Ir[/i] and [i]D. reticulatus (Dr[/i] ticks observed over the last decade, no effective control methods have been developed so far. The resent study was focused on assessment of the action of pyrethroids on these both tick species. materials and method. The different doses of four pyrethroids, i.e. deltamethrin – D (K-Othrine, permethrin – P (Copex WP, cypermethrin – C (Kordon 10WP, and alphacypermethrin – AC (Alfasekt 5SC were tested. The LD50 for each tested compound was also determined for both tick species. Unengorged and engorged (maintained on rabbit skin tick females were sprayed with 20ml of 0.01563–0.50% solutions of the tested preparations. results. The investigations showed that sensitivity of Ir and Dr to the tested pyrethroids, but the effects exerted by the different doses varied between both tick species and between engorged and unengorged females in these species. The strongest toxic effect on unengorged and engorged Ir and Dr females was exerted by D, whereas the effect of AC was weaker. The LD 50 (in µg/1 g b.w. of D, AC, C, and P for unengorged Ir and Dr females was, respectively, 55.4 and 25.5, 105.2 and 48.5, 225.9 and 197.7, and 553.8 and 380.8. In the case of engorged Ir and Dr females, the LD50 of AC, D, C, and P reached a value of 0.9453 and 0.2310, 1.0428 and 1.3533, 3.489 and 6.5662, and 8.3955 and 7.3940, respectively. conclusions. The differences between the effects of the tested pyrethroids and their different doses on Ir and Dr highlight the necessity for development of a strategy for control of the tick species in different regions, based on investigations of their sensitivity to chemical compounds.

  19. Examining Mechanisms of Pyrethroid Resistance in Eggs of Two Populations of the Chagas' Disease Vector Triatoma infestans (Hemiptera: Reduviidae).

    Science.gov (United States)

    Roca-Acevedo, G; Picollo, M I; Capriotti, N; Sierra, I; Santo-Orihuela, P L

    2015-09-01

    Chagas disease is a zoonosis transmitted to man by blood-sucking triatomine bugs found in the Americas. Triatoma infestans (Klug, 1834) is the main vector of Chagas' disease in Argentina. The control of this illness relies heavily on vector control through the use of insecticide. However, resistance to pyrethroid insecticides associated with ineffective field treatments has been increasingly reported in T. infestans from Argentina and Bolivia. There are few reports on the expression and causes of resistance in eggs of resistant populations, and even fewer studies on insecticide resistance throughout embryonic development. In this study, we explore the biochemical and molecular mechanisms potentially associated with the deltamethrin resistance assessed in the developing eggs of the Argentinean (Campo Largo) and Bolivian (Entre Ríos) T. infestans populations.We found measurable activity of monooxigenases and pyrethroid esterases throughout embryonic development. The pyrethroid esterase activity grew steadily throughout development in all the studied populations and was highest in eggs 12 d old. Mean enzyme activity increased from 13.6 to 16.3 and 22.2 picomol 7-hydroxycoumarin/min (7-OHC) in eggs of 4-, 7-, and 12 d old from the susceptible reference bug colony. Mean activity of resistant populations increased from 16.0 to 25.9 picomol 7-OHC/min in eggs of 4- to 12 d old in Entre Ríos population, and from 15.9 to 28.9 picomol 7-OHC/min in Campo Largo population. Molecular analysis of susceptible and resistant developing eggs detected L1014F mutation in both resistant populations, but no L925I mutation was found in any of the studied populations.Higher esterase activity and L1014F presence justify the resistance to pyrethroid throughout developing eggs of both studied T. infestans populations. The description of resistance profiles including resistance mechanisms involved will allow a rational design of campaigns for the control of Chagas disease transmission

  20. 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 48h), 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

  1. Comparison of the Insecticidal Characteristics of Commercially Available Plant Essential Oils Against Aedes aegypti and Anopheles gambiae (Diptera: Culicidae).

    Science.gov (United States)

    Norris, Edmund J; Gross, Aaron D; Dunphy, Brendan M; Bessette, Steven; Bartholomay, Lyric; Coats, Joel R

    2015-09-01

    Aedes aegypti and Anopheles gambiae are two mosquito species that represent significant threats to global public health as vectors of Dengue virus and malaria parasites, respectively. Although mosquito populations have been effectively controlled through the use of synthetic insecticides, the emergence of widespread insecticide-resistance in wild mosquito populations is a strong motivation to explore new insecticidal chemistries. For these studies, Ae. aegypti and An. gambiae were treated with commercially available plant essential oils via topical application. The relative toxicity of each essential oil was determined, as measured by the 24-h LD(50) and percentage knockdown at 1 h, as compared with a variety of synthetic pyrethroids. For Ae. aegypti, the most toxic essential oil (patchouli oil) was ∼1,700-times less toxic than the least toxic synthetic pyrethroid, bifenthrin. For An. gambiae, the most toxic essential oil (patchouli oil) was ∼685-times less toxic than the least toxic synthetic pyrethroid. A wide variety of toxicities were observed among the essential oils screened. Also, plant essential oils were analyzed via gas chromatography/mass spectrometry (GC/MS) to identify the major components in each of the samples screened in this study. While the toxicities of these plant essential oils were demonstrated to be lower than those of the synthetic pyrethroids tested, the large amount of GC/MS data and bioactivity data for each essential oil presented in this study will serve as a valuable resource for future studies exploring the insecticidal quality of plant essential oils. © 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.

  2. Neurobehavioral effects of exposure to organophosphates and pyrethroid pesticides among Thai children

    Science.gov (United States)

    Fiedler, Nancy; Rohitrattana, Juthasiri; Siriwong, Wattasit; Suttiwan, Panrapee; Strickland, Pam Ohman; Ryan, P. Barry; Rohlman, Diane S.; Panuwet, Parinya; Barr, Dana Boyd; Robson, Mark G.

    2015-01-01

    The use of pesticides for crop production has grown rapidly in Thailand during the last decade, resulting in significantly greater potential for exposure among children living on farms. Although some previous studies assessed exposures to pesticides in this population, no studies have been conducted to evaluate corresponding health effects. Twenty-four children from a rice farming community (exposed) and 29 from an aquaculture (shrimp) community (control) completed the study. Participants completed a neurobehavioral test battery three times at 6 month intervals: Session I: preliminary orientation; Session II: high pesticide use season; Session III: low pesticide-use season. Only sessions II and III were used in the analyses. High and low pesticide use seasons were determined by pesticide use on rice farms. Urinary metabolites of organophosphates (OPs) and pyrethroids (PYR) were analyzed from first morning void samples collected the day of neurobehavioral testing. Rice farm participants had significantly higher concentrations of dialkylphosphates (DAPs) (common metabolites of OPs) and TCPy (a specific metabolite of chlorpyrifos) than aquaculture farm children regardless of season. But, TCPy was significantly higher during the low rather than the high pesticide use season for both participant groups. Rice farm children had significantly higher DCCA, a metabolite of PYR, than aquaculture participants only during the high exposure season. Otherwise, no significant differences in PYR metabolites were noted between the participant groups or seasons. No significant adverse neurobehavioral effects were observed between participant groups during either the high or low pesticide use season. After controlling for differences in age and the Home Observation for Measurement of the Environment (HOME) scores, DAPs, TCPy, and PYR were not significant predictors of adverse neurobehavioral performance during either season. Increasing DAP and PYR metabolites predicted some relatively

  3. Extracts from Field Margin Weeds Provide Economically Viable and Environmentally Benign Pest Control Compared to Synthetic Pesticides.

    Directory of Open Access Journals (Sweden)

    Prisila Mkenda

    Full Text Available Plants with pesticidal properties have been investigated for decades as alternatives to synthetics, but most progress has been shown in the laboratory. Consequently, research on pesticidal plants is failing to address gaps in our knowledge that constrain their uptake. Some of these gaps are their evaluation of their efficacy under field conditions, their economic viability and impact on beneficial organisms. Extracts made from four abundant weed species found in northern Tanzania, Tithonia diversifolia, Tephrosia vogelii, Vernonia amygdalina and Lippia javanica offered effective control of key pest species on common bean plants (Phaseolus vulgaris that was comparable to the pyrethroid synthetic, Karate. The plant pesticide treatments had significantly lower effects on natural enemies (lady beetles and spiders. Plant pesticide treatments were more cost effective to use than the synthetic pesticide where the marginal rate of return for the synthetic was no different from the untreated control, around 4USD/ha, compared to a rate of return of around 5.50USD/ha for plant pesticide treatments. Chemical analysis confirmed the presence of known insecticidal compounds in water extracts of T. vogelii (the rotenoid deguelin and T. diversifolia (the sesquiterpene lactone tagitinin A. Sesquiterpene lactones and the saponin vernonioside C were also identified in organic extracts of V. amygdalina but only the saponin was recorded in water extracts which are similar to those used in the field trial. Pesticidal plants were better able to facilitate ecosystem services whilst effectively managing pests. The labour costs of collecting and processing abundant plants near farm land were less than the cost of purchasing synthetic pesticides.

  4. Extracts from Field Margin Weeds Provide Economically Viable and Environmentally Benign Pest Control Compared to Synthetic Pesticides.

    Science.gov (United States)

    Mkenda, Prisila; Mwanauta, Regina; Stevenson, Philip C; Ndakidemi, Patrick; Mtei, Kelvin; Belmain, Steven R

    2015-01-01

    Plants with pesticidal properties have been investigated for decades as alternatives to synthetics, but most progress has been shown in the laboratory. Consequently, research on pesticidal plants is failing to address gaps in our knowledge that constrain their uptake. Some of these gaps are their evaluation of their efficacy under field conditions, their economic viability and impact on beneficial organisms. Extracts made from four abundant weed species found in northern Tanzania, Tithonia diversifolia, Tephrosia vogelii, Vernonia amygdalina and Lippia javanica offered effective control of key pest species on common bean plants (Phaseolus vulgaris) that was comparable to the pyrethroid synthetic, Karate. The plant pesticide treatments had significantly lower effects on natural enemies (lady beetles and spiders). Plant pesticide treatments were more cost effective to use than the synthetic pesticide where the marginal rate of return for the synthetic was no different from the untreated control, around 4USD/ha, compared to a rate of return of around 5.50USD/ha for plant pesticide treatments. Chemical analysis confirmed the presence of known insecticidal compounds in water extracts of T. vogelii (the rotenoid deguelin) and T. diversifolia (the sesquiterpene lactone tagitinin A). Sesquiterpene lactones and the saponin vernonioside C were also identified in organic extracts of V. amygdalina but only the saponin was recorded in water extracts which are similar to those used in the field trial. Pesticidal plants were better able to facilitate ecosystem services whilst effectively managing pests. The labour costs of collecting and processing abundant plants near farm land were less than the cost of purchasing synthetic pesticides.

  5. Meeting Report: Synthetic Biology Jamboree for Undergraduates

    Science.gov (United States)

    Campbell, A. Malcolm

    2005-01-01

    The field of synthetic biology (the name is derived from an analogy to synthetic chemistry) has recognized itself as a "field" only since about 2002. Synthetic biology has gotten some high-profile attention recently, but most people are not aware the field even exists. Synthetic biologists apply engineering principles to genomic circuits to…

  6. Control theory meets synthetic biology.

    Science.gov (United States)

    Del Vecchio, Domitilla; Dy, Aaron J; Qian, Yili

    2016-07-01

    The past several years have witnessed an increased presence of control theoretic concepts in synthetic biology. This review presents an organized summary of how these control design concepts have been applied to tackle a variety of problems faced when building synthetic biomolecular circuits in living cells. In particular, we describe success stories that demonstrate how simple or more elaborate control design methods can be used to make the behaviour of synthetic genetic circuits within a single cell or across a cell population more reliable, predictable and robust to perturbations. The description especially highlights technical challenges that uniquely arise from the need to implement control designs within a new hardware setting, along with implemented or proposed solutions. Some engineering solutions employing complex feedback control schemes are also described, which, however, still require a deeper theoretical analysis of stability, performance and robustness properties. Overall, this paper should help synthetic biologists become familiar with feedback control concepts as they can be used in their application area. At the same time, it should provide some domain knowledge to control theorists who wish to enter the rising and exciting field of synthetic biology. © 2016 The Author(s).

  7. Synthetic biology, metaphors and responsibility.

    Science.gov (United States)

    McLeod, Carmen; Nerlich, Brigitte

    2017-08-29

    Metaphors are not just decorative rhetorical devices that make speech pretty. They are fundamental tools for thinking about the world and acting on the world. The language we use to make a better world matters; words matter; metaphors matter. Words have consequences - ethical, social and legal ones, as well as political and economic ones. They need to be used 'responsibly'. They also need to be studied carefully - this is what we want to do through this editorial and the related thematic collection. In the context of synthetic biology, natural and social scientists have become increasingly interested in metaphors, a wave of interest that we want to exploit and amplify. We want to build on emerging articles and books on synthetic biology, metaphors of life and the ethical and moral implications of such metaphors. This editorial provides a brief introduction to synthetic biology and responsible innovation, as well as a comprehensive review of literature on the social, cultural and ethical impacts of metaphor use in genomics and synthetic biology. Our aim is to stimulate an interdisciplinary and international discussion on the impact that metaphors can have on science, policy and publics in the context of synthetic biology.

  8. Esterase and glutathione S-transferase levels associated with synthetic pyrethroid resistance in Hyalomma anatolicum and Rhipicephalus microplus ticks from Punjab, India.

    Science.gov (United States)

    Nandi, Abhijit; Jyoti; Singh, Harkirat; Singh, Nirbhay Kumar

    2015-05-01

    Larval packet test was used for assessment of resistance status against cypermethrin and deltamethrin in Hyalomma anatolicum and Rhipicephalus microplus from various districts of Punjab (India). Among the various field isolates of H. anatolicum susceptible status was recorded against cypermethrin in all isolates, whereas against deltamethrin resistance status (level I-III) was recorded. In R. microplus lower resistance levels (I-II) were recorded against cypermethrin in comparison to deltamethrin (level I-IV). Quantitative analysis of general esterase activity revealed a range of 4.21 ± 0.46 to 6.05 ± 0.55 and 2.23 ± 0.23 to 2.66 ± 0.24 µmol/min/mg protein for α- and β-esterase activity, respectively, in different field isolates of H. anatolicum and the increase in comparison to susceptible was not significant (P > 0.05). In contrast to H. anatolicum, the α- and β-esterase activity in all field isolates (except Jalandhar) of R. microplus was higher (range of 3.89 ± 0.26 to 10.85 ± 0.47 and 1.75 ± 0.08 to 5.87 ± 0.29 µmol/min/mg protein, respectively) (P GST) activity in field isolates of H. anatolicum and R. microplus was in the range of 0.01 ± 0.001 to 0.03 ± 0.001 and 0.02 ± 0.0003 to 0.03 ± 0.001 mM/mg/min. The enzyme ratios (α-and β-esterase and GST) and RR95 against deltamethrin of H. anatolicum isolates were correlated (P < 0.05), whereas in R. microplus only α-and β-esterase and RR50 against deltamethrin were correlated (P < 0.05).

  9. Comparison of the effects of the synthetic pyrethroid Metofluthrin and phenobarbital on CYP2B form induction and replicative DNA synthesis in cultured rat and human hepatocytes

    International Nuclear Information System (INIS)

    Hirose, Yukihiro; Nagahori, Hirohisa; Yamada, Tomoya; Deguchi, Yoshihito; Tomigahara, Yoshitaka; Nishioka, Kazuhiko; Uwagawa, Satoshi; Kawamura, Satoshi; Isobe, Naohiko; Lake, Brian G.; Okuno, Yasuyoshi

    2009-01-01

    High doses of Metofluthrin (MTF) have been shown to produce liver tumours in rats by a mode of action (MOA) involving activation of the constitutive androstane receptor leading to liver hypertrophy, induction of cytochrome P450 (CYP) forms and increased cell proliferation. The aim of this study was to compare the effects of MTF with those of the known rodent liver tumour promoter phenobarbital (PB) on the induction CYP2B forms and replicative DNA synthesis in cultured rat and human hepatocytes. Treatment with 50 μM MTF and 50 μM PB for 72 h increased CYP2B1 mRNA levels in male Wistar rat hepatocytes and CYP2B6 mRNA levels in human hepatocytes. Replicative DNA synthesis was determined by incorporation of 5-bromo-2'-deoxyuridine over the last 24 h of a 48 h treatment period. Treatment with 10-1000 μM MTF and 100-500 μM PB resulted in significant increases in replicative DNA synthesis in rat hepatocytes. While replicative DNA synthesis was increased in human hepatocytes treated with 5-50 ng/ml epidermal growth factor or 5-100 ng/ml hepatocyte growth factor, treatment with MTF and PB had no effect. These results demonstrate that while both MTF and PB induce CYP2B forms in both species, MTF and PB only induced replicative DNA synthesis in rat and not in human hepatocytes. These results provide further evidence that the MOA for MTF-induced rat liver tumour formation is similar to that of PB and some other non-genotoxic CYP2B form inducers and that the key event of increased cell proliferation would not occur in human liver

  10. Microfluidic Technologies for Synthetic Biology

    Directory of Open Access Journals (Sweden)

    Sung Kuk Lee

    2011-06-01

    Full Text Available Microfluidic technologies have shown powerful abilities for reducing cost, time, and labor, and at the same time, for increasing accuracy, throughput, and performance in the analysis of biological and biochemical samples compared with the conventional, macroscale instruments. Synthetic biology is an emerging field of biology and has drawn much attraction due to its potential to create novel, functional biological parts and systems for special purposes. Since it is believed that the development of synthetic biology can be accelerated through the use of microfluidic technology, in this review work we focus our discussion on the latest microfluidic technologies that can provide unprecedented means in synthetic biology for dynamic profiling of gene expression/regulation with high resolution, highly sensitive on-chip and off-chip detection of metabolites, and whole-cell analysis.

  11. US Competitiveness in Synthetic Biology.

    Science.gov (United States)

    Gronvall, Gigi Kwik

    2015-01-01

    Synthetic biology is an emerging technical field that aims to make biology easier to engineer; the field has applications in strategically important sectors for the US economy. While the United States currently leads in synthetic biology R&D, other nations are heavily investing in order to boost their economies, which will inevitably diminish the US leadership position. This outcome is not entirely negative--additional investments will expand markets--but it is critical that the US government take steps to remain competitive: There are applications from which the US population and economy may benefit; there are specific applications with importance for national defense; and US technical leadership will ensure that US experts have a leading role in synthetic biology governance, regulation, and oversight. Measures to increase competitiveness in S&T generally are broadly applicable for synthetic biology and should be pursued. However, the US government will also need to take action on fundamental issues that will affect the field's development, such as countering anti-GMO (genetically modified organism) sentiments and anti-GMO legislation. The United States should maintain its regulatory approach so that it is the product that is regulated, not the method used to create a product. At the same time, the United States needs to ensure that the regulatory framework is updated so that synthetic biology products do not fall into regulatory gaps. Finally, the United States needs to pay close attention to how synthetic biology applications may be governed internationally, such as through the Nagoya Protocol of the Convention on Biological Diversity, so that beneficial applications may be realized.

  12. Synthetic biology as red herring.

    Science.gov (United States)

    Preston, Beth

    2013-12-01

    It has become commonplace to say that with the advent of technologies like synthetic biology the line between artifacts and living organisms, policed by metaphysicians since antiquity, is beginning to blur. But that line began to blur 10,000 years ago when plants and animals were first domesticated; and has been thoroughly blurred at least since agriculture became the dominant human subsistence pattern many millennia ago. Synthetic biology is ultimately only a late and unexceptional offshoot of this prehistoric development. From this perspective, then, synthetic biology is a red herring, distracting us from more thorough philosophical consideration of the most truly revolutionary human practice-agriculture. In the first section of this paper I will make this case with regard to ontology, arguing that synthetic biology crosses no ontological lines that were not crossed already in the Neolithic. In the second section I will construct a parallel case with regard to cognition, arguing that synthetic biology as biological engineering represents no cognitive advance over what was required for domestication and the new agricultural subsistence pattern it grounds. In the final section I will make the case with regard to human existence, arguing that synthetic biology, even if wildly successful, is not in a position to cause significant existential change in what it is to be human over and above the massive existential change caused by the transition to agriculture. I conclude that a longer historical perspective casts new light on some important issues in philosophy of technology and environmental philosophy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Studies with pyrethroids (kadethrin and deltamethrin) and lindane in ethanol sensitive (LS) and insensitive (SS) mouse strains

    Energy Technology Data Exchange (ETDEWEB)

    Doherty, J.; Baker, R.C.; Deitrich, R. (Univ. of Colorado, Denver (United States))

    1990-02-26

    Ethanol (E) sensitive (LS) and insensitive (SS) mouse strains are distinguished by their sleeping time to a given dose of E and the locus for this difference is at the level of the neuron. In attempts to understand the neuropharmacological basis of insecticide action and to further define the differences in these mouse lines, LS and SS mice were dosed with type I (kadethrine, K) and II (deltamethrin, D) pyrethroids and lindane (L). These compounds were selected because their proposed modes of action are on the Na+ channel (K and D) and/or the GABA receptor ionophore (D and L). No consistent differences in the effects of K, D or L in the SS and LS mouse lines were evident. In preliminary studies both SS and LS mice dosed with 50 or 100 {mu}g/brain of L (intracerebroventricularly) but not D slept much longer (2-3X) than when dosed with E alone, an effect opposite of that predicted from L's known excitatory action. These data indicate that as far as can be distinguished by pyrethroids and L, the Na+ channel and GABA receptor/ionophore complex are similar in both the LS and SS mouse lines.

  14. In vitro covalent binding of the pyrethroids cismethrin, cypermethrin and deltamethrin to rat liver homogenate and microsomes

    Energy Technology Data Exchange (ETDEWEB)

    Catinot, R.; Hoellinger, H.; Sonnier, M.; Do-Cao-Thang; Pichon, J.; Nguyen-Hoang-Nam

    1989-05-01

    Phenobarbital-induced rat liver homogenate and microsomes were used to study covalent binding of /sup 14/C-labelled (at the alcohol moiety) cismethrin, /sup 14/C-labelled (at the alcohol and acid moieties) cypermethrin, and /sup 14/C-labelled (at the alcohol and acid moieties) deltamethrin. Covalent binding was dependent on pyrethroid concentration. With liver homogenate, inhibition of esterases by tetraethylpyrophosphate and of mitochondrial respiration by rotenone or potassium cyanide only slightly altered the covalent binding level. With microsomes, inhibition of cytochrome P-450 and mixed function oxidases by carbon monoxide and piperonyl butoxide reduced the covalent binding so far as to be nearly absent. Eighty percent inhibition of epoxide hydrolase decreased the covalent binding by 50%. The comparison of data between alcohol and acid labelling of the same pyrethroid suggested that, in vitro, the whole molecule is bound to proteins and that hydrolysis can occur afterwards. The experiments stress the role of cytochrome P-450-dependent monoxygenases in the covalent binding process. (orig.).

  15. A GIS model-based screening of potential contamination of soil and water by pyrethroids in Europe.

    Science.gov (United States)

    Pistocchi, A; Vizcaino, P; Hauck, M

    2009-08-01

    The paper presents a geographic information system (GIS) model-based approach for analysis of potential contamination of soil and water by pyrethroids for the European continent. Pyrethroids are widely used pesticides and their chemical and toxicological characteristics suggest there may be concerns about human health and ecosystems, although so far there is no strong evidence indicating actual risk. However, little monitoring has been conducted and limited experimental information is available. We perform an assessment exercise that demonstrates how accessible information and GIS-based modeling allow to estimate the spatial distribution of chemical concentrations and fluxes at a screening level. The assessment highlights potential hot spots and the main environmental transport pathways, in a quick and simple way. By combining information on pesticide use, crop distribution and landscape and climate parameters we identify potential problem areas to help focusing monitoring campaigns. The approach presented here is simple and fast, and can be applied to virtually all pesticide classes used over a large domain, and is therefore suitable for the screening of large quantities of chemicals, of which the majority has not undergone any systematic environmental monitoring program. The method has been tested through benchmarking with other well-established models. However, further research is needed to evaluate it against experimental observations.

  16. Occurrence, seasonal variation and inhalation exposure of atmospheric organophosphate and pyrethroid pesticides in an urban community in South China.

    Science.gov (United States)

    Li, Huizhen; Ma, Hongzhu; Lydy, Michael J; You, Jing

    2014-01-01

    The shift in pesticide usage patterns demands a better understanding of the occurrence, fate and exposure risk of atmospheric current-use pesticides (CUPs). Air samples collected in different seasons from an urban community in Guangzhou, China were analyzed to investigate seasonal variation, gas-particle partitioning and inhalation exposure of atmospheric organophosphate and pyrethroid pesticides. Chlorpyrifos and eight pyrethroids were detected in the air samples and the total concentrations of the nine CUPs ranged from 150 to 3816 pg m(-3). Chlorpyrifos and cypermethrin were the most dominant CUPs detected in the atmosphere, accounting for 68% and 15% of the total CUPs, respectively. Seasonal variation in concentration was observed for most CUPs, with peak concentrations occurring in summer and fall, which was consistent with their application patterns. Partitioning of chlorpyrifos between gas and particle phases was also seasonally-dependent, with more chlorpyrifos found in the gas phase in summer and fall. Additionally, gas-particle partitioning analysis suggested that chlorpyrifos might experience long-range transport. Evaluation of potential exposure from inhalation of atmospheric CUPs suggested that children, toddlers and infants had the highest exposure, but the risk quotients were low for all age groups when annual average concentrations were used as exposure metrics. Exposure risk was higher in summer and fall than the annual average level due to higher atmospheric pesticide concentrations, longer exposure times and more pesticides being in the gaseous form. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Synthetic Phage for Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    So Young Yoo

    2014-01-01

    Full Text Available Controlling structural organization and signaling motif display is of great importance to design the functional tissue regenerating materials. Synthetic phage, genetically engineered M13 bacteriophage has been recently introduced as novel tissue regeneration materials to display a high density of cell-signaling peptides on their major coat proteins for tissue regeneration purposes. Structural advantages of their long-rod shape and monodispersity can be taken together to construct nanofibrous scaffolds which support cell proliferation and differentiation as well as direct orientation of their growth in two or three dimensions. This review demonstrated how functional synthetic phage is designed and subsequently utilized for tissue regeneration that offers potential cell therapy.

  18. Synthetic biology and its promises

    Directory of Open Access Journals (Sweden)

    José Manuel De Cózar Escalante

    2016-12-01

    Full Text Available Synthetic biology is a new science and emerging technology, or rather a technoscience, which converges with others such as nanotechnology, information technology, robotics, artificial intelligence and neuroscience. All have common features that could have highly concerning social and environmental impacts. With its ambitious goals of controlling complexity, redesigning and creating new living entities, synthetic biology perfectly exemplifies the new bioeconomic reality. This requires expanding the focus of the discussion beyond the limited comparative analysis of risks and benefits, to address uncertainties, reassign responsibilities and initiate a thorough social assessment of what is at stake.

  19. Synthetic methodologies for carbon nanomaterials.

    Science.gov (United States)

    Liu, Zhaoping; Zhou, Xufeng; Qian, Yitai

    2010-05-04

    Carbon nanomaterials have advanced rapidly over the last two decades and are among the most promising materials that have already changed and will keep on changing human life. Development of synthetic methodologies for these materials, therefore, has been one of the most important subjects of carbon nanoscience and nanotechnology, and forms the basis for investigating the physicochemical properties and applications of carbon nanomaterials. In this Research News article, several synthetic strategies, including solvothermal reduction, solvothermal pyrolysis, hydrothermal carbonization, and soft-chemical exfoliation are specifically discussed and highlighted, which have been developed for the synthesis of novel carbon nanomaterials over the last decade.

  20. Cotton pest management practices and the selection of pyrethroid resistance in Anopheles gambiae population in Northern Benin

    Directory of Open Access Journals (Sweden)

    Yadouleton Anges

    2011-04-01

    Full Text Available Abstract Background Pyrethroid insecticides, carbamate and organophosphate are the classes of insecticides commonly used in agriculture for crop protection in Benin. Pyrethroids remain the only class of insecticides recommended by the WHO for impregnation of bed nets. Unfortunately, the high level of pyrethroid resistance in Anopheles gambiae s.l., threatens to undermine the success of pyrethroid treated nets. This study focuses on the investigation of agricultural practices in cotton growing areas, and their direct impact on larval populations of An. gambiae in surrounding breeding sites. Methods The protocol was based on the collection of agro-sociological data where farmers were subjected to semi-structured questionnaires based on the strategies used for crop protection. This was complemented by bioassay tests to assess the susceptibility of malaria vectors to various insecticides. Molecular analysis was performed to characterize the resistance genes and the molecular forms of An. gambiae. Insecticide residues in soil samples from breeding sites were investigated to determine major factors that can inhibit the normal growth of mosquito larvae by exposing susceptible and resistant laboratory strains. Results There is a common use by local farmers of mineral fertilizer NPK at 200 kg/ha and urea at 50 kg/hectare following insecticide treatments in both the Calendar Control Program (CCP and the Targeted Intermittent Control Program (TICP. By contrast, no chemicals are involved in Biological Program (BP where farmers use organic and natural fertilizers which include animal excreta. Susceptibility test results confirmed a high resistance to DDT. Mean mortality of An. gambiae collected from the farms practicing CCP, TICP and BP methods were 33%, 42% and 65% respectively. An. gambiae populations from areas using the CCP and TICP programs showed resistance to permethrin with mortality of 50% and 58% respectively. By contrast, bioassay test results of