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Sample records for prevent fingernail clams

  1. Digital image analysis of fingernail colour in cadavers comparing carbon monoxide poisoning to controls.

    Science.gov (United States)

    Langlois, Neil E I

    2010-03-01

    Carbon monoxide is a component of motor vehicle exhaust fumes, provided a functional catalytic converter is not present. This gas binds avidly to the hemoglobin molecule in red blood cells preventing its oxygen transport function, effectively poisoning the body by starving it of oxygen. In binding to hemoglobin, carbon monoxide forms carboxyhemoglobin, which has a characteristic bright pink color. It has been remarked that the fingernails of victims of carbon monoxide tend to exhibit pink color, otherwise fingernails of deceased bodies tend towards a dark red to blue color. This study sought to objectively determine by using digital image analysis if a color difference occurred between the fingernails of a group of cadavers with carbon monoxide poisoning compared to a group of controls. The fingernails of the carbon monoxide group did tend to be more red than the controls, but due to overlap between the two groups assessment of the fingernails cannot be recommended as a rapid screening test.

  2. Fingernails Yield Clues to Limb Regeneration

    Science.gov (United States)

    ... Spotlight on Research Fingernails Yield Clues to Limb Regeneration By Kirstie Saltsman, Ph.D. | January 5, 2014 ... Diseases has uncovered chemical signals that drive the regeneration of lost digit tips in mice. The findings, ...

  3. Manganese Concentrations In Hair and Fingernail of Some Kano ...

    African Journals Online (AJOL)

    Manganese concentrations in hair and fingernails were determined by Flame Atomic Absorption Spectrometry (AAS).The mean manganese in hair and fingernail were 0.54 ± 0.35mg/g and 0.68 ± 0.30mg/g respectively. A progressive decrease in manganese concentrations in hair and fingernails with age indicated no ...

  4. EXAMINATION OF FINGERNAIL CONTENTS AND STOOL FOR

    African Journals Online (AJOL)

    Computer Center

    intestinal helminths and protozoa. The objective of this study was to determine the level of fingernail ... prevalence rates of the major protozoan and helminthic infections (1,2). Intestinal parasites have been widely distributed in ..... Methods of Food-borne Disease. Control With Special reference to. Ethiopia. 1997; 32-59. 14.

  5. Fingernails as biological indices of metal exposure

    Indian Academy of Sciences (India)

    This paper deals with the quantitative determination of Cd, Pb, Cr, Mn, Fe, Ni, Cu, and Zn concentrations in nails of male subjects exposed to these metals ... of Cd, Pb, Cr, Mn, Fe, Ni, Cu and Zn in fingernails, assayed by atomic absorption spectrophotometry, were compared with their respective controls by student '' test.

  6. Split Fingernails: Can They Be Prevented?

    Science.gov (United States)

    ... induced disorders of the nail with update on contemporary nail manicures. The Journal of Clinical and Aesthetic ... Mayo," "Mayo Clinic," "MayoClinic.org," "Mayo Clinic Healthy Living," and the triple-shield Mayo Clinic logo are ...

  7. Factors influencing EPR dosimetry in fingernails

    International Nuclear Information System (INIS)

    Dubner, D.L.; Spinella, M.R.; Bof, E.

    2010-01-01

    The technique based on the detection of ionizing radiation induced radicals by EPR in tooth enamel is an established method for the dosimetry of exposed persons in radiological emergencies. Dosimetry based on EPR spectral analysis of fingernail clippings, currently under development, has the practical advantage of the easier sample collection. A limiting factor is that overlapping the radiation induced signal (RIS), fingernails have shown the presence of two mechanically induced signals, called MIS1 and MIS2, due to elastic and plastic deformation respectively, at the time of fingernails cutting. With a water treatment, MIS1 is eliminated while MIS2 is considerably reduced. The calibration curves needed for radiation accident dosimetry should have 'universal' characteristics, ie. Represent the variability that can be found in different individuals. Early studies were directed to the analysis of factors affecting the development of such universal calibration curves. The peak to peak amplitude of the signal before and after the water treatment as well as the effect of size and number of clippings were studied. Furthermore, the interpersonal and intrapersonal variability were analyzed. Taking into account these previous studies, the optimal conditions for measurement were determined and EPR spectra of samples irradiated at different doses were used for the developing of dose-response curves. This paper presents the analysis of the results.(authors) [es

  8. Stable isotope composition of human fingernails from Slovakia

    Energy Technology Data Exchange (ETDEWEB)

    Grolmusová, Zuzana, E-mail: zuzana.grolmusova@geology.sk [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia); Rapčanová, Anna [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); Michalko, Juraj; Čech, Peter [State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia); Veis, Pavel [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia)

    2014-10-15

    Stable isotope composition of human fingernails has proven to be useful for documenting human dietary information and geographical patterns in archeological, forensic, anthropological and biological studies. Therefore, it is of interest to detect all factors influencing the stable isotopic composition in the certain regions in the world. Carbon and nitrogen isotope data of human fingernail keratin from 52 individuals from Slovakia were reported in this study. The online combustion and continuous flow isotope-ratio mass spectrometer Delta V Advantage was used for δ{sup 13}C and δ{sup 15}N analysis of fingernail keratin samples from 24 vegetarian and 28 omnivorous individuals. A group of people with frequent meat consumption showed enrichment in {sup 13}C and {sup 15}N isotopes in fingernails. A similar trend was observed with increasing seafood in an individual's diet. Moreover a significant difference was revealed between smokers and nonsmokers for both δ{sup 13}C and δ{sup 15}N values. These data were compared to previously published δ{sup 13}C and δ{sup 15}N fingernail values from across the globe. This study brings new information on the stable isotope signature of individuals from Slovakia and characterizes the Central European region for the first time. The stable isotope composition of fingernails is influenced by the frequency of meat and seafood consumption as well as smoking. - Highlights: • This study deals with stable isotope analyses of fingernails from Slovak volunteers. • δ{sup 13}C and δ{sup 15}N values of vegetarian and omnivore fingernails were compared. • Influence of sex, diet and smoking was studied.

  9. Stable isotope composition of human fingernails from Slovakia

    International Nuclear Information System (INIS)

    Grolmusová, Zuzana; Rapčanová, Anna; Michalko, Juraj; Čech, Peter; Veis, Pavel

    2014-01-01

    Stable isotope composition of human fingernails has proven to be useful for documenting human dietary information and geographical patterns in archeological, forensic, anthropological and biological studies. Therefore, it is of interest to detect all factors influencing the stable isotopic composition in the certain regions in the world. Carbon and nitrogen isotope data of human fingernail keratin from 52 individuals from Slovakia were reported in this study. The online combustion and continuous flow isotope-ratio mass spectrometer Delta V Advantage was used for δ 13 C and δ 15 N analysis of fingernail keratin samples from 24 vegetarian and 28 omnivorous individuals. A group of people with frequent meat consumption showed enrichment in 13 C and 15 N isotopes in fingernails. A similar trend was observed with increasing seafood in an individual's diet. Moreover a significant difference was revealed between smokers and nonsmokers for both δ 13 C and δ 15 N values. These data were compared to previously published δ 13 C and δ 15 N fingernail values from across the globe. This study brings new information on the stable isotope signature of individuals from Slovakia and characterizes the Central European region for the first time. The stable isotope composition of fingernails is influenced by the frequency of meat and seafood consumption as well as smoking. - Highlights: • This study deals with stable isotope analyses of fingernails from Slovak volunteers. • δ 13 C and δ 15 N values of vegetarian and omnivore fingernails were compared. • Influence of sex, diet and smoking was studied

  10. Infection of Manila clams Ruditapes philippinarum from Galicia (NW Spain) with a Mikrocytos-like parasite.

    Science.gov (United States)

    Ramilo, Andrea; Iglesias, David; Abollo, Elvira; González, Mar; Darriba, Susana; Villalba, Antonio

    2014-07-24

    The name 'microcells' is frequently used to refer to small-sized unicellular stages of molluscan parasites of the genera Bonamia (Rhizaria, Haplosporidia) and Mikrocytos (Rhizaria). Histological examination of Manila clams Ruditapes philippinarum revealed microcells in the connective tissue of adductor muscle, foot, mantle, gills, siphon and visceral mass. The clams had been collected from 4 beds on the coast of Galicia, Spain. The prevalence of these microcells ranged from 73 to 93% in surface clams and from 3 to 33% in buried clams. However, the detection of brown ring disease signs in clams from every bed prevented us from making the assumption that the microcells alone were responsible for clam mortality. PCR assays using primer pairs designed to detect Bonamia spp. and haplosporidians gave negative results, whereas positive results were obtained with primers for the genus Mikrocytos. A consensus sequence of 1670 bp of the ribosomal gene complex of the microcells was obtained. It contained a section of the 18S region, the whole first internal transcribed spacer, the 5.8S region, the second internal transcribed spacer and a section of the 28S region. Comparison of this sequence with those of M. mackini infecting Crassostrea gigas and Mikrocytos sp. infecting Ostrea edulis showed that the microcells of Galician clams were the most divergent among the compared parasites. This is the first report of a Mikrocytos-like parasite infecting Manila clams. Care must be taken to avoid the spread of this parasite through Manila clam transfers.

  11. New trace element determinations in the fingernails of ALS patients

    Energy Technology Data Exchange (ETDEWEB)

    Van Dalsem, D.J.; Robinson, L. [Oak Ridge National Lab., TN (United States); Ehmann, W.D. [Kentucky Univ., Lexington, KY (United States). Dept. of Chemistry

    1996-02-01

    ORNL`s High Flux Isotope Reactor was used in a neutron activation analysis experiment to determine selected elemental composition of fingernails from patients afflicted with amyotrophic lateral sclerosis (AL). While no statistical difference were found in aluminium a suggestive difference was observed for copper concentrations.

  12. New trace element determinations in the fingernails of ALS patients

    International Nuclear Information System (INIS)

    Van Dalsem, D.J.; Robinson, L.; Ehmann, W.D.

    1996-01-01

    ORNL's High Flux Isotope Reactor was used in a neutron activation analysis experiment to determine selected elemental composition of fingernails from patients afflicted with amyotrophic lateral sclerosis (AL). While no statistical difference were found in aluminium a suggestive difference was observed for copper concentrations

  13. Intestinal parasites from fingernails of sidewalk food vendors

    Directory of Open Access Journals (Sweden)

    Suriptiastuti

    2011-08-01

    Full Text Available Intestinal infections with soil-transmitted helminths and protozoa are still prevalent in Indonesia, particularly in urban communities. Transmission of parasitic infections is effected directly or indirectly through objects contaminated with feces, including food, water, fingers and fingernails, indicating the importance of fecal-oral human-to-human transmission. Sidewalk food vendors (SFVs preparing food for their customers are a potential source of infections with many intestinal helminths and protozoa. Compared to other parts of the hand, the area beneath fingernails harbors the most microorganisms and is most difficult to clean. The objective of this cross-sectional study was to determine the prevalence of intestinal parasites in fingernail dirt of SFVs and to identify the associated factors. This study involved 112 SFVs in the vicinity of Hospital X in Central Jakarta, and used microscopic examination of SFV fingernail dirt for determining species prevalence of intestinal parasites. This study showed that 94 samples out of 112 (83.9% were positive for intestinal parasites; 60 samples (63.8% represented single infections and 34 (36.2% mixed infections. Ascaris lumbricoides eggs were found in 30 (26.8% samples and Giardia lamblia cysts in 12 (17.89%. The highest prevalence was found in subjects with primary school education, among whom 20 (30.8% had single infections of A. lumbricoides and 16 (24.6% mixed infections with A. lumbricoides and Trichuris trichiura. In conclusion, prevalence of intestinal parasites in SFV fingernail dirt is extremely high, with the highest prevalence among less educated SFVs. It is recommended to provide health education and training to all SFVs.

  14. Intestinal parasites from fingernails of sidewalk food vendors

    Directory of Open Access Journals (Sweden)

    Suriptiastuti Suriptiastuti

    2016-02-01

    Full Text Available Intestinal infections with soil-transmitted helminths and protozoa are still prevalent in Indonesia, particularly in urban communities. Transmission of parasitic infections is effected directly or indirectly through objects contaminated with feces, including food, water, fingers and fingernails, indicating the importance of fecal-oral human-to-human transmission. Sidewalk food vendors (SFVs preparing food for their customers are a potential source of infections with many intestinal helminths and protozoa. Compared to other parts of the hand, the area beneath fingernails harbors the most microorganisms and is most difficult to clean. The objective of this cross-sectional study was to determine the prevalence of intestinal parasites in fingernail dirt of SFVs and to identify the associated factors. This study involved 112 SFVs in the vicinity of Hospital X in Central Jakarta, and used microscopic examination of SFV fingernail dirt for determining species prevalence of intestinal parasites. This study showed that 94 samples out of 112 (83.9% were positive for intestinal parasites; 60 samples (63.8% represented single infections and 34 (36.2% mixed infections. Ascaris lumbricoides eggs were found in 30 (26.8% samples and Giardia lamblia cysts in 12 (17.89%. The highest prevalence was found in subjects with primary school education, among whom 20 (30.8% had single infections of A. lumbricoides and 16 (24.6% mixed infections with A. lumbricoides and Trichuris trichiura. In conclusion, prevalence of intestinal parasites in SFV fingernail dirt is extremely high, with the highest prevalence among less educated SFVs. It is recommended to provide health education and training to all SFVs.

  15. 21 CFR 102.49 - Fried clams made from minced clams.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Fried clams made from minced clams. 102.49 Section 102.49 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Nonstandardized Foods § 102.49 Fried clams made from minced clams. (a) The common or usual name of the food...

  16. Photosymbiotic giant clams are transformers of solar flux.

    Science.gov (United States)

    Holt, Amanda L; Vahidinia, Sanaz; Gagnon, Yakir Luc; Morse, Daniel E; Sweeney, Alison M

    2014-12-06

    'Giant' tridacnid clams have evolved a three-dimensional, spatially efficient, photodamage-preventing system for photosymbiosis. We discovered that the mantle tissue of giant clams, which harbours symbiotic nutrition-providing microalgae, contains a layer of iridescent cells called iridocytes that serve to distribute photosynthetically productive wavelengths by lateral and forward-scattering of light into the tissue while back-reflecting non-productive wavelengths with a Bragg mirror. The wavelength- and angle-dependent scattering from the iridocytes is geometrically coupled to the vertically pillared microalgae, resulting in an even re-distribution of the incoming light along the sides of the pillars, thus enabling photosynthesis deep in the tissue. There is a physical analogy between the evolved function of the clam system and an electric transformer, which changes energy flux per area in a system while conserving total energy. At incident light levels found on shallow coral reefs, this arrangement may allow algae within the clam system to both efficiently use all incident solar energy and avoid the photodamage and efficiency losses due to non-photochemical quenching that occur in the reef-building coral photosymbiosis. Both intra-tissue radiometry and multiscale optical modelling support our interpretation of the system's photophysics. This highly evolved 'three-dimensional' biophotonic system suggests a strategy for more efficient, damage-resistant photovoltaic materials and more spatially efficient solar production of algal biofuels, foods and chemicals.

  17. 50 CFR 648.72 - Minimum surf clam size.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Minimum surf clam size. 648.72 Section 648... Atlantic Surf Clam and Ocean Quahog Fisheries § 648.72 Minimum surf clam size. (a) Minimum length. The minimum length for surf clams is 4.75 inches (12.065 cm). (b) Determination of compliance. No more than 50...

  18. A study of association between fingernail elements and osteoporosis by laser-induced breakdown spectroscopy

    Science.gov (United States)

    Bahreini, Maryam; Hosseinimakarem, Zahra; Hassan Tavassoli, Seyed

    2012-09-01

    Laser induced breakdown spectroscopy (LIBS) is used to investigate the possible effect of osteoporosis on the elemental composition of fingernails. Also, the ability to classify healthy, osteopenic, and osteoporotic subjects based on their fingernail spectra has been examined. 46 atomic and ionic emission lines belonging to 13 elements, which are dominated by calcium and magnesium, have been identified. Measurements are carried out on fingernail clippings of 99 subjects including 27 healthy, 47 osteopenic, and 25 osteoporotic subjects. The Pearson correlations between spectral intensities of different elements of fingernail and age and bone mineral densities (BMDs) in nail samples are calculated. Correlations between line intensities of some elements such as sodium and potassium, calcium and iron, magnesium and silicon and also between some fingernail elements, BMD, and age are observed. Although some of these correlations are weak, some information about mineral metabolism can be deduced from them. Discrimination between nail samples of healthy, osteopenic, and osteoporotic subjects is shown to be somehow possible by a discriminant function analysis using 46 atomic emission lines of the LIBS spectra as input variables. The results of this study provide some evidences for association between osteoporosis and elemental composition of fingernails measured by LIBS.

  19. The susceptibility of Irish-grown and Galician-grown Manila clams, Ruditapes philippinarum, to Vibrio tapetis and Brown Ring Disease.

    Science.gov (United States)

    Drummond, Linda C; Balboa, Sabela; Beaz, Roxana; Mulcahy, Máire F; Barja, Juan L; Culloty, Sarah C; Romalde, Jesús L

    2007-05-01

    Brown Ring Disease (BRD), which affects the Manila clam in Europe, is caused by the bacterium, Vibrio tapetis. BRD has been diagnosed in Ireland on only one occasion (1997) although the aetiological agent has recently been detected in apparently healthy Manila clams from a number of sites around the Irish coast. The present work investigated the susceptibilities to BRD of two stocks of Manila clams, one from Ireland and the second from Galicia, north-western Spain, where BRD has been reported on a number of occasions. Exposure of the clams was by addition of V. tapetis to the holding waters. Development of BRD was assessed by the appearance of brown ring signs on the host shells, by bacterial isolation and characterization, and by detection of the bacterium by PCR. The pathogen was recovered from infected individuals and confirmed as V. tapetis by biochemical tests and a slide agglutination test. Galician clams experienced significantly higher mortalities, BRD prevalences and V. tapetis levels than Irish clams. Background infection with V. tapetis in the control stocks prevented conclusions being drawn on comparative susceptibility of the two stocks. Irish clams were significantly affected by the experimental challenge, as demonstrated by the development of BRD and an increase in V. tapetis levels. Results illustrate the vulnerability of Irish clams to BRD and have implications for the movement and transfer of clam seed in Ireland.

  20. New trace element determinations in the fingernails of ALS patients

    Energy Technology Data Exchange (ETDEWEB)

    Van Dalsem, D.J.; Ehmann, W.D. [Univ. of Kentucky, Lexington, KY (United States); Robinson, L. [Oak Ridge National Laboratory, TN (United States)

    1996-12-31

    Amyotrophic lateral sclerosis (ALS) afflicts 2 of every 100,000 people in the United States each year. A well-known example of ALS today is Stephen Hawking. He is a theoretical physicist, the author of A Brief History of Time, and is virtually immobilized by ALS. Diseases that cause progressive paralysis because of motor neuron degeneration in the central nervous system are termed motor neuron disorders (MND). Amyotrophic lateral sclerosis is a common form of MND. Pain-free, progressive muscular weakness is the most common clinical symptom. There is chronic weakness with atrophy of the affected muscles by the time the disease is diagnosed. Atrophy eventually results in wheelchair confinement and then only bed without the ability to speak or swallow. Death often occurs as a result of respiratory problems. Unlike other neurodegenerative diseases, in ALS the patient`s bladder and bowel control, eye movement, and mental faculties are preserved. The question today is whether or not certain trace elements are involved in the etiology or pathogenesis of ALS. A collaborative study was undertaken by the University of Kentucky and Oak Ridge National Laboratory (ORNL) using neutron activation analysis (NAA) to study trace element concentrations in ALS patients fingernails to determine if there existed statistically significant imbalances.

  1. Validation of fingernail fluoride concentration as a predictor of risk for dental fluorosis.

    Science.gov (United States)

    Buzalaf, M A R; Massaro, C S; Rodrigues, M H C; Fukushima, R; Pessan, J P; Whitford, G M; Sampaio, F C

    2012-01-01

    The aim of this study was to validate the use of fingernail fluoride concentrations at ages 2-7 years as predictors of the risk for developing dental fluorosis in the permanent dentition. Fifty-six children of both genders (10-15 years of age) had their incisors and premolars examined for dental fluorosis using the Thylstrup-Fejerskov index. Fingernail fluoride concentrations were obtained from previous studies when children were 2-7 years of age. Data were analyzed by unpaired t test, ANOVA, and Fisher's exact test when the fingernail fluoride concentrations were dichotomized (≤ 2 or >2 µg/g). Children with dental fluorosis had significantly higher fingernail fluoride concentrations than those without the condition, and the concentrations tended to increase with the severity of fluorosis (r(2) = 0.47, p dental fluorosis. The high positive predictive value indicates that fingernail fluoride concentrations should be useful in public health research, since it has the potential to identify around 80% of children at risk of developing dental fluorosis. Copyright © 2012 S. Karger AG, Basel.

  2. Human fingernail as interpositional graft material in the treatment of nasal septal perforations.

    Science.gov (United States)

    Akçal, Arzu; Karsidag, Semra; Ozkaya, Ozay; Sirvan, Selami Serhat; Sevim, Kamuran Zeynep; Kabukcuoglu, Fevziye

    2014-04-01

    The etiology of nasal septal perforations involves iatrogenic, traumatic, inflammatory, infectious, neoplastic, and caustic causes. To ensure successful closure, an appropriate interpositional graft material should be selected, and this graft material should be covered with healthy tissue. The study included 18 New Zealand white rabbits weighing 2 to 2.5 kg. Nasal septal perforations were created in group 1. After the creation of defects in group 2, repair was performed with cartilage graft and bilateral mucoperichondrial advancement flaps. After septal nasal perforations in group 3, the defect was covered with fingernail and bilateral mucoperichondrial flaps. At week 12, the rabbits were sacrificed. The septum site that had been repaired with fingernail was intact. No nail exposition, wound site decomposition, or re-perforation was observed. No findings of a breach of the structural integrity of the fingernails or disintegration were encountered. Fingernails can be used as an interpositional graft material in place of cartilage in eligible cases for the repair of nasal septal perforations. Fingernails have several properties that enable their use in such cases, such as form preservation that is similar to cartilage, the lack of live cells, easy availability, and a lack of donor-site morbidity at removal. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  3. Significance of fingernail and toenail mercury concentrations as biomarkers for prenatal methylmercury exposure in relation to segmental hair mercury concentrations.

    Science.gov (United States)

    Sakamoto, Mineshi; Chan, Hing M; Domingo, José L; Oliveira, Ricardo B; Kawakami, Shoichi; Murata, Katsuyuki

    2015-01-01

    To investigate the appropriateness of mercury (Hg) concentrations in fingernails and toenails at parturition for detecting prenatal exposure to methylmercury (MeHg). Total Hg concentrations were measured in 54 paired samples of fingernails, toenails, maternal blood, and maternal hair (1cm incremental segments from the scalp toward the tip) collected at 4th weeks of (early) pregnancy, and the same specimens and cord blood collected at parturition. Strong correlations were observed between Hg concentrations in fingernails and toenails at early pregnancy (r=0.923, pMercury concentrations in fingernails and toenails at parturition represented strong correlations with those in cord blood (r=0.803, pMercury in fingernails and toenails at early pregnancy reflected the maternal Hg body burden level approximately 5 months retroactively. At parturition, Hg levels in fingernails and toenails also showed strong correlations with those in cord blood. In addition, Hg levels in fingernails and toenails at parturition reflected more recent MeHg exposure, compared with those at early pregnancy. These results suggest that fingernails and toenails at parturition are useful biomarkers for prenatal MeHg exposure for mothers and fetuses, especially during the third-trimester of gestation. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Nickel concentrations in fingernails as a measure of occupational exposure to nickel

    DEFF Research Database (Denmark)

    Peters, K; Gammelgaard, Bente; Menné, T

    1991-01-01

    in nails (p less than 0.001). The difference between the 2 levels was also significant (p less than 0.001). No correlation between the nickel concentration in fingernails and the duration of exposure could be demonstrated. It was concluded that the higher the nickel level in the fingernails, the greater...... is the possibility that the person is occupationally exposed to nickel. Nail analysis is suggested as a measure of occupational exposure to nickel.......The nickel concentration in fingernails from 2 groups of people occupationally exposed to nickel was determined. In one group, comprising 83 persons moderately exposed to nickel, the mean +/- standard deviation (SD) was 29.2 micrograms/g +/- 56.7 micrograms/g and the median 13.8 micrograms/g (range...

  5. The Clam Trail: Blending Science Education, Public Art, and Tourism

    Science.gov (United States)

    Muscio, Cara; Flimlin, Gef; Bushnell, Rick

    2011-01-01

    The Barnegat Bay Shellfish Restoration's Clam Trail is an award-winning scavenger hunt that combines science education, public art, and tourism. This family adventure has participants seeking out giant painted fiberglass clams, upweller clam nurseries, and points of interest in search of science facts to record on their forms. Upon returning these…

  6. Continuous cooling transformation behaviors of CLAM steel

    International Nuclear Information System (INIS)

    Wu, Qing-sheng; Zheng, Shu-hui; Huang, Qun-ying; Liu, Shao-jun; Han, Yang-yang

    2013-01-01

    The continuous cooling transformation (CCT) behaviors of CLAM (China Low Activation Martensitic) steel were studied, the CCT diagram was constructed, and the influence of cooling rates on the microstructures was also investigated. The microstructures were investigated using optical microscopy (OM) and microhardness tests were also carried out. The results showed that CLAM steel possessed high hardenability and there were ferrite and martensite transformation regions only. The maximum cooling rate to form ferrite microstructure was found to be 10–12 K/min. In order to obtain fully ferrite microstructure, the cooling rate should be lower than 1 K/min. The CCT diagram also gave relevant parameters such as the transformation temperatures, i.e., A c1 , A c3 , M s and M f were 1124 K, 1193 K, 705 K and 593 K, respectively. The diagram made it possible to predict the microstructures and properties of CLAM steel with different cooling rates

  7. Response of the Asiatic clam, Corbicula manilensis, to gamma radiation

    International Nuclear Information System (INIS)

    Tilly, L.J.; Corey, J.C.; Bibler, N.E.

    1977-01-01

    When heat exchangers for reactors were plugged by the Asiatic clam, acute gamma radiation was considered as a possible control. Clams were collected and sorted by size; during irradiation the clams were submerged in natural water. Clams of both sizes survived large doses with no radiation damage evident in 30 days. Mortality rose steeply at doses of 2.4 x 10 4 Rad and above; smaller clams showed a greater resistance than large ones. The feasibility of using periodic exposure to gamma radiation as a means for controlling corbicula infestations is discussed

  8. Cortisol levels in fingernails, neurocognitive performance and clinical variables in euthymic bipolar I disorder.

    Science.gov (United States)

    Herane-Vives, Andres; Cleare, Anthony J; Chang, Chin-Kuo; de Angel, Valeria; Papadopoulos, Andrew; Fischer, Susanne; Halari, Rozmin; Cheung, Eric Y W; Young, Allan H

    2017-03-27

    Neurocognitive impairment has been found in bipolar patients. Hypercortisolemia is one possible cause but there has been no agreement on this. Previous sampling methods assessed only acute cortisol levels, whereas the association between cortisol and psychopathology might be better understood by investigating chronic levels. Fingernails are a novel method for measuring chronic cortisol concentration (CCC). Here, we measured CCC in euthymic bipolar disorder I (BD-I) patients and healthy controls using fingernails to investigate whether differences in CCC influenced neurocognitive performance. We also investigated whether differences in clinical illness variables influenced CCC in euthymic BD-I patients. A previous study demonstrated neurocognitive impairment in euthymic BD-I patients. The current study included a portion of this sample: 40 BD-I versus 42 matched controls who provided fingernail samples. There was no statistically significant difference in CCC between controls and BD-I (P = .09). Logistic regression analyses revealed that euthymic bipolar I subjects with more than five years of current euthymia had decreased odds of having higher fingernail cortisol concentration (>71.2 pg/mg) compared to those with less than 1.5 years (P = .04). There was no association between CCC and cognitive impairment in all domains before and after adjustment for age and sex. The current evidence suggests CCC is not a trait biomarker in euthymic BD-I (BD-I). Longer periods of stability in affective disorders are associated with lower CCC. Fingernail cortisol does not seem to be implicated in neurocognitive impairment and BD-I. Future studies may investigate CCC in different illness phases of BD-I.

  9. Pickle from blood clam (Anadara granosa) meat

    OpenAIRE

    Gupta, S.S.; Basu, S.

    1985-01-01

    A pickle was prepared from blood clam (Anadara granosa) meat. The pickle was subjected to biochemical, bacteriological and organoleptic tests at different stages of storage. The pickle has a shelf-life of more than 5½ months at ambient temperature.

  10. Epidemiology of Human Papillomavirus (HPV) Detected in the Oral Cavity and Fingernails of Mid-Adult Women

    Science.gov (United States)

    Fu, Tsung-chieh (Jane); Hughes, James P.; Feng, Qinghua; Hulbert, Ayaka; Hawes, Stephen E.; Xi, Long Fu; Schwartz, Stephen M.; Stern, Joshua E.; Koutsky, Laura A.; Winer, Rachel L.

    2015-01-01

    Background Oral and fingernail human papillomavirus (HPV) detection may be associated with HPV-related carcinoma risk at these non-genital sites and foster transmission to the genitals. We describe the epidemiology of oral and fingernail HPV among mid-adult women. Methods Between 2011–2012, 409 women aged 30–50 years were followed for 6 months. Women completed health and behavior surveys and provided self-collected oral, fingernail, and vaginal specimens at enrollment and exit for type-specific HPV DNA testing. Concordance of type-specific HPV detection across anatomic sites was described with kappa statistics. Using generalized estimating equations or exact logistic regression, we measured the univariate associations of various risk factors with type-specific oral and fingernail HPV detection. Results Prevalence of detecting HPV in the oral cavity (2.4%) and fingernails (3.8%) was low compared to the vagina (33.1%). Concordance across anatomic sites was poor (kappaHPV type (OR=101.0;95%CI: 31.4–748.6) and vaginal HPV viral load (OR per one log10 viral load increase=2.2;95%CI:1.5–5.5) were each associated with fingernail HPV detection. Abnormal Pap history (OR=11.1;95%CI:2.8-infinity), lifetime number of male vaginal sex partners ≥10 (OR vs. 0–3 partners=5.0;95%CI:1.2-infinity), and lifetime number of open-mouth kissing partners ≥16 (OR vs. 0–15 partners=infinity;95%CI:2.6-infinity, by exact logistic regression) were each associated with oral HPV detection. Conclusions While our findings support HPV DNA deposition or autoinoculation between anatomic sites in mid-adult women, the rarity of HPV in the oral cavity and fingernails suggests that oral/fingernail HPV does not account for a significant fraction of HPV in genital sites. PMID:26562696

  11. Analysis of trace elements in the shell of asari clams

    International Nuclear Information System (INIS)

    Arakawa, J.; Sakamoto, W.; Arai, N.; Yoshida, K.

    1999-01-01

    Strontium concentration in the shells of asari clams collected at different locations was analyzed by PIXE. The Sr concentration of external surface of shell umbo was ranged from 1000 to 3500 ppm for individuals. The Sr concentration of clams collected at Shirahama showed positive correlation with shell length, whereas clams collected at Maizuru did not show significant correlation. This result may be caused from the difference of the spawning seasons between two areas. (author)

  12. Continuous cooling transformation behaviors of CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qing-sheng, E-mail: qingsheng.wu@fds.org.cn; Zheng, Shu-hui; Huang, Qun-ying; Liu, Shao-jun; Han, Yang-yang

    2013-11-15

    The continuous cooling transformation (CCT) behaviors of CLAM (China Low Activation Martensitic) steel were studied, the CCT diagram was constructed, and the influence of cooling rates on the microstructures was also investigated. The microstructures were investigated using optical microscopy (OM) and microhardness tests were also carried out. The results showed that CLAM steel possessed high hardenability and there were ferrite and martensite transformation regions only. The maximum cooling rate to form ferrite microstructure was found to be 10–12 K/min. In order to obtain fully ferrite microstructure, the cooling rate should be lower than 1 K/min. The CCT diagram also gave relevant parameters such as the transformation temperatures, i.e., A{sub c1}, A{sub c3}, M{sub s} and M{sub f} were 1124 K, 1193 K, 705 K and 593 K, respectively. The diagram made it possible to predict the microstructures and properties of CLAM steel with different cooling rates.

  13. Relative element levels in the paired samples of scalp hair and fingernails of patients from New Delhi

    Energy Technology Data Exchange (ETDEWEB)

    Sukumar, A. [School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110 067 (India)]. E-mail: sukumarindia@rediffmail.com; Subramanian, R. [School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110 067 (India)

    2007-01-01

    Specific elements are bioconcentrated in human hair and nails, which have unique advantages of application in population monitoring studies thereby, recognized as biological tools for disease diagnosis and prevention. However, investigations are meager for relative element profile in hair and nails of same subjects. In this study, hair and nails were analyzed to find effects of age, sex, smoking habit, diet, urban and rural exposure gradients, occupation, and health on element levels. Scalp hair and fingernails were sampled along with a questionnaire from urban and rural subjects of New Delhi; patients of hypertension, coronary heart disease, and diabetes were identified clinically. Cadmium, chromium, copper, nickel, lead and zinc concentrations were determined by AAS in both the samples; CRM (human hair powder) analysis showed acceptable precision and accuracy in element measurement. In comparison to controls, Cr-H and Zn-H levels were lower respectively in female hypertensive and total hypertensive subjects, whereas, Zn-N and Cu-N were lower respectively in total CHD and diabetic subjects, and hypertensive and CHD urban subjects. Cd concentrations were higher in both the samples of tobacco smoking rural subjects than that of non-smokers. Farmers had lower Pb-H than rural businessmen did. Cr, Cu, Ni, and Zn concentrations were different due to rural and urban gradient but not to the influence of age, sex, and diet. Pb value was alone correlated between the paired samples. Thus, higher Cd levels in the smokers and lower Cr, Cu and Zn levels in the patients were observed.

  14. Relative element levels in the paired samples of scalp hair and fingernails of patients from New Delhi

    International Nuclear Information System (INIS)

    Sukumar, A.; Subramanian, R.

    2007-01-01

    Specific elements are bioconcentrated in human hair and nails, which have unique advantages of application in population monitoring studies thereby, recognized as biological tools for disease diagnosis and prevention. However, investigations are meager for relative element profile in hair and nails of same subjects. In this study, hair and nails were analyzed to find effects of age, sex, smoking habit, diet, urban and rural exposure gradients, occupation, and health on element levels. Scalp hair and fingernails were sampled along with a questionnaire from urban and rural subjects of New Delhi; patients of hypertension, coronary heart disease, and diabetes were identified clinically. Cadmium, chromium, copper, nickel, lead and zinc concentrations were determined by AAS in both the samples; CRM (human hair powder) analysis showed acceptable precision and accuracy in element measurement. In comparison to controls, Cr-H and Zn-H levels were lower respectively in female hypertensive and total hypertensive subjects, whereas, Zn-N and Cu-N were lower respectively in total CHD and diabetic subjects, and hypertensive and CHD urban subjects. Cd concentrations were higher in both the samples of tobacco smoking rural subjects than that of non-smokers. Farmers had lower Pb-H than rural businessmen did. Cr, Cu, Ni, and Zn concentrations were different due to rural and urban gradient but not to the influence of age, sex, and diet. Pb value was alone correlated between the paired samples. Thus, higher Cd levels in the smokers and lower Cr, Cu and Zn levels in the patients were observed

  15. Gamma Radiation Processing of Clam (Galatea Paradoxa Born ...

    African Journals Online (AJOL)

    Gamma Radiation Processing of Clam (Galatea Paradoxa Born 1778) from the Volta River Estuary for Microbiological Decontamination. ... The Clam (Galatea paradoxa Born 1778) is a dermesal dweller of riverine water and filter feed by passing water through gut concentrating particulate matter including bacteria in the gut ...

  16. Freshwater clams as bioconcentrators of avian influenza virus in water.

    Science.gov (United States)

    Huyvaert, Kathryn P; Carlson, Jenny S; Bentler, Kevin T; Cobble, Kacy R; Nolte, Dale L; Franklin, Alan B

    2012-10-01

    We report experimental evidence for bioconcentration of a low-pathogenicity avian influenza virus (H6N8) in the tissue of freshwater clams. Our results support the concept that freshwater clams may provide an effective tool for use in the early detection of influenza A viruses in aquatic environments.

  17. The behaviour of giant clams (Bivalvia: Cardiidae: Tridacninae).

    Science.gov (United States)

    Soo, Pamela; Todd, Peter A

    2014-01-01

    Giant clams, the largest living bivalves, live in close association with coral reefs throughout the Indo-Pacific. These iconic invertebrates perform numerous important ecological roles as well as serve as flagship species-drawing attention to the ongoing destruction of coral reefs and their associated biodiversity. To date, no review of giant clams has focussed on their behaviour, yet this component of their autecology is critical to their life history and hence conservation. Almost 100 articles published between 1865 and 2014 include behavioural observations, and these have been collated and synthesised into five sections: spawning, locomotion, feeding, anti-predation, and stress responses. Even though the exact cues for spawning in the wild have yet to be elucidated, giant clams appear to display diel and lunar periodicities in reproduction, and for some species, peak breeding seasons have been established. Perhaps surprisingly, giant clams have considerable mobility, ranging from swimming and gliding as larvae to crawling in juveniles and adults. Chemotaxis and geotaxis have been established, but giant clams are not phototactic. At least one species exhibits clumping behaviour, which may enhance physical stabilisation, facilitate reproduction, or provide protection from predators. Giant clams undergo several shifts in their mode of acquiring nutrition; starting with a lecithotrophic and planktotrophic diet as larvae, switching to pedal feeding after metamorphosis followed by the transition to a dual mode of filter feeding and phototrophy once symbiosis with zooxanthellae ( Symbiodinium spp.) is established. Because of their shell weight and/or byssal attachment, adult giant clams are unable to escape rapidly from threats using locomotion. Instead, they exhibit a suite of visually mediated anti-predation behaviours that include sudden contraction of the mantle, valve adduction, and squirting of water. Knowledge on the behaviour of giant clams will benefit

  18. Ixekizumab treatment improves fingernail psoriasis in patients with moderate-to-severe psoriasis: results from the randomized, controlled and open-label phases of UNCOVER-3

    NARCIS (Netherlands)

    Kerkhof, P. van de; Guenther, L.; Gottlieb, A.B.; Sebastian, M.; Wu, J.J.; Foley, P.; Morita, A.; Goldblum, O.; Zhang, L.; Erickson, J.; Ball, S.; Rich, P.

    2017-01-01

    BACKGROUND: Fingernail psoriasis is difficult to treat. OBJECTIVE: The objective was to evaluate the effect of ixekizumab, a monoclonal antibody selectively targeting IL-17A, on fingernail psoriasis. METHODS: This Phase 3, double-blind trial (UNCOVER-3) randomized patients to placebo, etanercept

  19. Trace element determination in fingernails, hair and blood serum in patients with Crohn's disease using neutron activation analysis

    International Nuclear Information System (INIS)

    Buschmann, H.

    1984-01-01

    The determination of trace elements and electrolyte concentrations in blood serum, hair and fingernails of 16 patients with Crohn's disease was carried out by means of instrumental neutron activation analysis. In the serum a significant decline in the zinc content could be registered, while the remaining trace elements remained in the normal range. The parenteral nutrition also showed a zinc deficiency. There was, however, also an iron deficiency. The studies of the hair and fingernails gave the following results: Rubidium and antimony in the normal range; zinc, selenium, iron and cobalt below normal values. (orig./PW) [de

  20. Manila clam Venerupis philippinarum as a biomonitor to metal pollution

    Science.gov (United States)

    Wu, Huifeng; Ji, Chenglong; Wang, Qing; Liu, Xiaoli; Zhao, Jianmin; Feng, Jianghua

    2013-01-01

    The Manila clam Venerupis philippinarum is a good biomonitor/bioindicator to marine metal pollution and is frequently used in aquatic toxicology. Two dominant pedigrees (white and zebra) of clam are distributed in the Bohai Sea; however, little attention has been paid to potential biological differences between these two pedigrees. In this study, we tested the sensitivity of both pedigrees to marine metal (cadmium and zinc) pollution biomonitoring and marine environmental toxicology. Results demonstrate significant biological differences in gills of white and zebra clams based on metabolic profiles and antioxidant enzyme activities. In addition, we found that hypotaurine, malonate and homarine were relatively high in white clam gills, while alanine, arginine, glutamate, succinate, 4-aminobutyrate, taurine and betaine were high in zebra clam gills. Zebra clam gills were also more sensitive to a mixture of Cd and Zn, as shown by antioxidant enzyme activities and metabolic profiles, but white clam gills could accumulate more Zn. Therefore, we suggest that the white pedigree can be used as a biomonitor to marine Zn pollution, whereas the zebra pedigree can be used for toxicology studies on Cd and Zn mixed pollution.

  1. Elemental concentration distribution in human fingernails – A 3D study

    International Nuclear Information System (INIS)

    Pineda-Vargas, C.A.; Mars, J.A.; Gihwala, D.

    2012-01-01

    The verification of pathologies has normally been based on analysis of blood (serum and plasma), and physiological tissue. Recently, nails and in particular human fingernails have become an important medium for pathological studies, especially those of environmental origin. The analytical technique of PIXE has been used extensively in the analysis of industrial samples and human tissue specimens. The application of the analytical technique to nails has been mainly to bulk samples. In this study we use micro-PIXE and -RBS, as both complementary and supplementary, to determine the elemental concentration distribution of human fingernails of individuals. We report on the 3D quantitative elemental concentration distributions (QECDs) of various elements that include C, N and O as major elements (10–20%), P, S, Cl, K and Ca as minor elements (1–10%) and Fe, Mn, Zn, Ti, Na, Mg, Cu, Ni, Cr, Rb, Br, Sr and Se as trace elements (less than 1%). For PIXE and RBS the specimens were bombarded with a 3 MeV proton beam. To ascertain any correlations in the quantitative elemental concentration distributions, a linear traverse analysis was performed across the width of the nail. Elemental distribution correlations were also obtained.

  2. The effects of clam fishing on the properties of surface sediments in the lagoon of Venice, Italy

    Directory of Open Access Journals (Sweden)

    R. J. Aspen

    2004-01-01

    Full Text Available Harvesting of clams(Tapes philippinarum has important socio-economic and environmental implications for the Venice lagoon area, Italy. Clam harvesting disrupts the structure of benthic communities but the effects upon sediment stability and surface structure remain unclear. The effect of clam fishing on the sediment properties of the lagoon bed was investigated at two different sites, a heavily fished site (San Angelo and an infrequently fished site (San Giaccomo. Both sites were assessed for immediate impacts of fishing, using indicators of biogenic sediment stabilisation. Samples were taken at three points along three 100 m linear transects at each site prior to and post fishing. Paired samples were also taken parallel to each transect at a distance of 5m, to allow for temporal variation. Sediment stability, measured with a cohesive strength meter (CSM, was significantly higher at the less impacted site (F1,34 = 6.23, p a (chl a, colloidal-S carbohydrate and dry bulk density were observed on the transect after fishing but not adjacent to the fishing path. At the heavily impacted site, clam fishing by trawling had, in general, no significant effect on the biological and physical properties (although chl a did decrease significantly after fishing. The lack of a significant impact from fishing at the impacted site was attributed to the higher frequency of fishing occurring in this area. Hence, frequent fishing of the lagoon prevents establishment of biotic communities, preventing biostabilisation and thus reduces the stability of the surface sediment. Keywords: clam harvesting, erosion threshold, microphytobenthos, sediment, stability

  3. Triage of populations potentially exposed to clinically significant doses of ionizing radiation using EPR measurements of fingernails and toenails

    International Nuclear Information System (INIS)

    Swartz, Harold

    2008-01-01

    Full text: Purpose: Under the sponsorship of NIH and DARPA a multidisciplinary, multi-institutional team is developing a field deployable device capable of carrying out triage under field conditions for large numbers of exposed individuals. Method The approach involves the development of two different techniques to obtain sufficiently accurate measurements of radiation-induced EPR signals in fingernails and toenails: in vivo in situ on the finger or toe and in vitro on clippings. The in vivo measurements from fingernails in situ use a 9500 MHz (X-band) EPR spectrometer with a resonator that is being developed specifically for making measurements in human subjects, based on finite element modelling to probe only the relative non-lossy fingernail plate and not the underlying lossy tissue. The approach based on clippings from toenails and fingernails using an adaptation of a commercial EPR spectrometer with modified resonators to achieve increased sensitivity and enhanced rapid and accurate positioning of the samples. For both approaches, post-acquisition software using the known characteristics of the radiation-induced EPR signal provides the estimate of the exposure dose. Major Findings: Between the time of submission and the meeting there will be a very intense period of research supported by a contract from DARPA and the continuing research supported by NIH, so the findings summarized here are expected to advance significantly in the interval. The technique based on the clippings of fingernails builds on the developments of collaborating scientists, especially A. Romanyukha and F. Trompier, which have shown that dose sufficient for triage can be resolved if adequate estimates of the signals induced by the clipping process ('MIS') can be made. The use of added water for removal of the mechanically induced signal appears very promising. A resonator for the in vivo approach that has the desirable features has been designed and that design is being optimized and then

  4. Ancient Clam Gardens Increased Shellfish Production: Adaptive Strategies from the Past Can Inform Food Security Today

    Science.gov (United States)

    Groesbeck, Amy S.; Rowell, Kirsten; Lepofsky, Dana; Salomon, Anne K.

    2014-01-01

    Maintaining food production while sustaining productive ecosystems is among the central challenges of our time, yet, it has been for millennia. Ancient clam gardens, intertidal rock-walled terraces constructed by humans during the late Holocene, are thought to have improved the growing conditions for clams. We tested this hypothesis by comparing the beach slope, intertidal height, and biomass and density of bivalves at replicate clam garden and non-walled clam beaches in British Columbia, Canada. We also quantified the variation in growth and survival rates of littleneck clams (Leukoma staminea) we experimentally transplanted across these two beach types. We found that clam gardens had significantly shallower slopes than non-walled beaches and greater densities of L. staminea and Saxidomus giganteus, particularly at smaller size classes. Overall, clam gardens contained 4 times as many butter clams and over twice as many littleneck clams relative to non-walled beaches. As predicted, this relationship varied as a function of intertidal height, whereby clam density and biomass tended to be greater in clam gardens compared to non-walled beaches at relatively higher intertidal heights. Transplanted juvenile L. staminea grew 1.7 times faster and smaller size classes were more likely to survive in clam gardens than non-walled beaches, specifically at the top and bottom of beaches. Consequently, we provide strong evidence that ancient clam gardens likely increased clam productivity by altering the slope of soft-sediment beaches, expanding optimal intertidal clam habitat, thereby enhancing growing conditions for clams. These results reveal how ancient shellfish aquaculture practices may have supported food security strategies in the past and provide insight into tools for the conservation, management, and governance of intertidal seascapes today. PMID:24618748

  5. Effect of low salinity on the yellow clam Mesodesma mactroides

    Directory of Open Access Journals (Sweden)

    YBM. Carvalho

    Full Text Available The aim of this study was to determine the lethal salinity (LC50 for the yellow clam Mesodesma mactroides (Bivalvia: Mesodesmatidae and identify histopathological alterations that could be used to diagnose structural changes in clam tissue. Clams in two size classes (adults and juveniles were placed in 10 L chambers and exposed to salinities of 35, 30, 25, 20, 15, 10, and 5 g/L. There were triplicate chambers with seven clams each for each salinity. The LC50 values for a 48 h exposure were 6.5 g/L and 5.7 g/L for adults and juveniles, respectively. For a 96 h exposure, the LC50 values were 10.5 g/L for adults and 8.8 g/L for juveniles. The histological examination of yellow clams exposed to 10 g/L for 96 h showed intercellular oedema and necrotic foci in the epithelium of the digestive gland and occlusion of the lumen of the digestive gland. In conclusion, M. mactroides can be characterised as a moderately euryhaline species, tolerating salinities from 35 to 15 g/L.

  6. Toxicity of a traditional molluscicide to asian clam veligers

    Science.gov (United States)

    Layhee, Megan J.; ,; Miho Yoshioka,; Bahram Farokhkish,; ,; Gross, Jackson A.; Sepulveda, Adam J.

    2014-01-01

    Aquaculture and hatchery industries are in need of effective control methods to reduce the risk of spreading aquatic invasive species, such as the Asian clam Corbicula fluminea, through aquaculture and hatchery activities. The planktonic nature of Asian clam veligers enables this life stage to enter water-based infrastructure undetected, including hatchery trucks used to stock fish. Once in hatchery trucks, veligers can disperse overland and establish in previously uninvaded habitats. As a result, there is a need to develop techniques that result in veliger mortality but do not harm fish. In September 2012, we conducted laboratory trials to determine if a molluscicide (750 mg/L potassium chloride and 25 mg/L formalin) commonly used to kill zebra mussel (Dreissena polymorpha) veligers in hatchery trucks can also effectively kill Asian clam veligers. We exposed Asian clam veligers to this molluscicide for 1, 3, and 5 h in each of two water types: deionized water and filtered lake water. We found ,20% mortality at the 1-h exposure period and 100% mortality at both the 3-h and 5-h exposure periods, regardless of water type. This laboratory study represents an important step toward reducing the spread of Asian clams by aquaculture facilities.

  7. Interpretation of laser desorption mass spectra of unexpected inorganic species found in a cosmetic sample of forensic interest: fingernail polish.

    Science.gov (United States)

    O'Neill, Emily; Harrington, Danielle; Allison, John

    2009-08-01

    When analytes containing color are irradiated with a pulsed UV laser in the ion source of a mass spectrometer, molecules such as dyes or pigments absorb energy, resulting in their desorption and ionization. This method, laser desorption mass spectrometry (LDMS), has been used successfully to analyze colorants of forensic interest in a wide variety of materials. Here, we present and interpret the most complex of such spectra obtained to date from a sample of fingernail polish. Interpretation of the spectrum provides a unique opportunity to characterize the laser desorption mass spectra of some unexpected inorganic materials found in cosmetics, such as "broken glass", cyanide compounds, and heavy metals. Also, the possibility of a useful forensic database of LDMS spectra of fingernail polishes is considered.

  8. Freshwater clam extract supplementation improves wound healing by decreasing the tumor necrosis factor α level in blood.

    Science.gov (United States)

    Peng, Yi-Chi; Fwu-LinYang; Subeq, Yi-Maun; Tien, Chin-Chieh; Lee, Ru-Ping

    2017-03-01

    The freshwater clam (Corbicula fluminea) is a widely consumed functional food in Asia and is traditionally used to improve health and either prevent or treat inflammation-related diseases. Numerous studies have proposed that freshwater clams act to prevent and attenuate inflammatory responses, and also serve as a possible inhibitor to systemic inflammation. However, there is limited information available about the effects of freshwater clams on wound healing. The present study investigated the influence of freshwater clam extract (FCE) on wound healing and inflammatory responses in a cutaneous incision model. Sixteen rats were used and divided into two groups: the FCE group and the normal saline (NS) group. The rats underwent dorsal full-thickness skin excisional wounds (diameter 20 × 10 mm). FCE or NS was administered for oral feeding twice daily for 14 days after wounding. Blood samples were taken and analyzed, and wound areas were measured at several time points during the 2 weeks after excision. On day 14 after wounding, skin biopsies from the wound sites were sent for histological examination. Treatment with FCE (71.63 ± 9.51 pg mL -1 ) decreased tumor necrosis factor-α levels compared to the NS group (109.86 ± 12.55 pg mL -1 ) after wounding at 3 h (P group (23.9%) were larger than those in the FCE group (8.26%) on day 14 (P group. FCE supplementation improves the wound healing process. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  9. Fingernail biting increase the risk of soil transmitted helminth (STH infection in elementary school children

    Directory of Open Access Journals (Sweden)

    Liena Sofiana

    2012-07-01

    Transmitted Helminth (STH infections in elementary school.Methods: A cross sectional study with purposive sampling method was carried out in a primary school children in a area of a Yogyakarta health Center from October to December 2009. Stool was examined by using the Kato Katz method and pupils were interviewed by questionnaires.Results: Two hundred and eleven subjects participated in this study, and 52 subjects (24.6% had STH infection. The most frequent STH infection was Trichuris trichiura, and the least was mixed infection (Ascaris lumbricoides, Trichuris trichiura and Hookworm. The highest risk (2.8-fold occurred among those with a habit of fingernail biting compared to those who did not bite fingernails [adjusted relative risk (RRa = 2.80; 95% confidence interval (CI = 1.22-4.04]. No hand washing before meals as well as no hand washing with soap after passing stool also increased the risk of STH infection by 2.2-fold.Conclusion: Fingernail biting and no hand washing before meals as well as no hand washing with soap after passing stool increased the risk of STH infections. (Health Science Indones 2011;2:81-6. 

  10. Performance Characteristics of AOAC Method 2005.06 for the Determination of Paralytic Shellfish Toxins in Manila Clams, European Otter Clams, Grooved Carpet Shell Clams, Surf Clams, and Processed King Scallops.

    Science.gov (United States)

    O'Neill, Alison; Turner, Andrew D

    2015-01-01

    An approach was developed for the verification of method performance of the AOAC 2005.06 LC-fluorescence detector (FLD) method for determination of paralytic shellfish poisoning (PSP) toxins in bivalve shellfish. This was developed following advice published by the Analytical Laboratory Accreditation Criteria Committee and applied to shellfish species that had not been previously subjected to a full single-laboratory validation scheme. The refined approach was developed following the need to assess performance in a number of shellfish species infrequently monitored through the UK statutory monitoring program, while reducing the impact and cost of the studies, most notably in terms of the use of valuable reference standards. The species assessed were manila clams (Ruditapes philippinarum), European otter clams (Lutraria lutraria), grooved carpet shell clams (R. decussatus), surf clams (Spisula solida), and king scallops (Pecten maximus) presented as adductor only or adductor plus roe. The method was assessed for sensitivity in terms of LOD and LOQ, toxin recovery, and method precision in each species. It incorporated the PSP toxins deemed toxic and/or prevalent in UK samples and commercially available as certified reference standards. The toxins studied included GTX1-5, dcSTX, STX, C1&2, and NEO. The toxins dcGTX2&3 were included for surf clams due to the prevalence of these toxins in this species as a result of toxin decarbamoylation. Method performance targets were met for each of the characteristics investigated. Consequently, the method was deemed fit for purpose for the screening and quantification of these clam and scallop species for PSP toxins by AOAC Method 2005.06 LC-FLD.

  11. Evaluating the prevalence of DNA mixtures found in fingernail samples from victims and suspects in homicide cases.

    Science.gov (United States)

    Nurit, Bublil; Anat, Gast; Michal, Shenfeld; Lilach, Front; Maya, Freund

    2011-11-01

    An important aspect of homicide investigations is the identification of the persons that had the last contact with the victim prior to death. Violent crimes are frequently characterized by a struggle between the victim and the perpetrator where biological material can be expected to be exchanged between them. Forensic DNA typing enables the generation of genetic profiles by extraction and amplification of cellular material found under fingernails. The evidential value of these samples may be critical if the secondary contributor found in a DNA mixture, can be matched with a potential suspect, or through a DNA database search. The amount of biological material transferred under the fingernails during "casual" activities is not sufficient to genotype reportable mixtures. This may not be the case with homicide victims that may have struggled and died under violent circumstances. The aim of this study was to evaluate the prevalence of DNA mixtures found under the fingernails of both victims and suspected perpetrators of violent deaths. We present a retrospective study of 137 DNA profiles genotyped from fingernail samples of homicide victims and suspects, collected at the Israeli National Center of Forensic Medicine. The majority of the samples produced single source profiles (n=107, 78%) that matched those of the donor's. DNA mixtures (n=30, 22%) were found in increased frequency among victims (n=25/100, 25%) compared to suspects (n=5/37, 13.5%). Mixtures were sub-divided into high level (n=15, 50%), low level (n=9, 30%) and residual (n=6, 20%), according to the number of the foreign contributors' alleles. Thus, this distinctive group of homicide victims was found to express both elevated frequency of DNA mixtures together with highly informative value of the secondary foreign profiles, as compared to other studied populations. These findings support an important aspect for the criminal investigation in murder cases, where a struggle may have ensued and the

  12. Isotopic Analysis of Fingernails as a USGS Open House Demonstration of the Use of Stable Isotopes in Foodweb Studies

    Science.gov (United States)

    Silva, S. R.; Kendall, C.; Young, M. B.; Choy, D.

    2011-12-01

    The USGS Isotope Tracers Project uses stable isotopes and tritium to add a unique dimension of chemical information to a wide range of environmental investigations. The use and application of isotopes is usually an unfamiliar and even esoteric topic to the general public. Therefore during three USGS open house events, as a public outreach effort, we demonstrated the use of stable isotopes by analyzing nitrogen and carbon isotopes from very small fragments of fingernail from willing participants. We titled the exhibit "You Are What You Eat". The results from all participants were plotted on a graph indicating the general influence of different food groups on the composition of body tissues as represented by fingernails. All participants were assigned a number and no personal-identification information was collected. A subset of participants provided us with an estimate of the number of days a week various foods were eaten and if they were vegetarians, vegans or non-vegetarians. Volunteers from our research group were on hand to explain and discuss fundamental concepts such as how foods attain their isotopic composition, the difference between C3 and C4 plants, the effects of assimilation, trophic enrichment, and the various uses of stable isotopes in environmental studies. The results of the fingernail analyses showed the variation of the range of isotopic compositions among about 400 people at each event, the distinct influence of C4 plants (mainly corn and cane sugar) on our carbon isotopic composition, and the isotopic differences between vegetarians and non vegetarians among other details (http://wwwrcamnl.wr.usgs.gov/isoig/projects/fingernails/). A poll of visitors attending the open house event in 2006 indicated that "You Are What You Eat" was among the most popular exhibits. Following the first two open house events we were contacted by a group of researchers from Brazil who had completed a very similar study. Our collaboration resulted in a publication in

  13. Effects of predation by sea ducks on clam abundance in soft-bottom intertidal habitats

    Science.gov (United States)

    Lewis, Tyler; Esler, Daniel N.; Boyd, W. Sean

    2007-01-01

    Recent studies have documented strong, top-down predation effects of sea ducks on mussel populations in rocky intertidal communities. However, the impact of these gregarious predators in soft-bottom communities has been largely unexplored. We evaluated effects of predation by wintering surf scoters Melanitta perspicillata and white-winged scoters M. fusca on clam populations in soft-bottom intertidal habitats of the Strait of Georgia, British Columbia. Specifically, we documented spatial and temporal variation in clam density (clams m–2), scoter diet composition, and the consequences of scoter predation on clam abundance. Of the 3 most numerous clams, Manila clams Venerupis philippinarum and varnish clams Nuttallia obscurata were the primary prey items of both scoter species, while clams of the genus Macoma were rarely consumed by scoters. Between scoter arrival in the fall and departure in the spring, Manila clams decreased in density at most sample sites, while varnish clam densities did not change or declined slightly. Our estimates of numbers of clams consumed by scoters accounted for most of the observed declines in combined abundance of Manila and varnish clams, despite the presence of numerous other vertebrate and invertebrate species known to consume clams. For Macoma spp., we detected an over-winter increase in density, presumably due to growth of clams too small to be retained by our sieve (<5 mm) during fall sampling, in addition to the lack of predation pressure by scoters. These results illustrate the strong predation potential of scoters in soft-bottom intertidal habitats, as well as their potentially important role in shaping community structure.

  14. Antiproliferative activity of protein extracts from the black clam ...

    African Journals Online (AJOL)

    Hiessu

    2016-02-24

    Feb 24, 2016 ... 2F2 showed IC50 values of 67.46 µg/ml on HeLa cells. These results suggest that protein extracts from. C. fluctifraga might be potential anticancer agents. Key words: Protein extracts, clam, antiproliferative activity, breast cancer, cervical cancer. INTRODUCTION. Cancer is a worldwide health issue; it is not ...

  15. The Clam-Gallas Palace in Prague: Emblematic Architecture?

    Czech Academy of Sciences Publication Activity Database

    Konečný, Lubomír

    2010-01-01

    Roč. 18, - (2010), s. 1-10 ISSN 0885-968X Institutional research plan: CEZ:AV0Z80330511 Keywords : Clam-Gallas Palace * Johann Bernhard Fischer von Erlach * architecture * emblem s * imprints Subject RIV: AL - Art, Architecture, Cultural Heritage

  16. Understanding arsenic metabolism through a comparative study of arsenic levels in the urine, hair and fingernails of healthy volunteers from three unexposed ethnic groups in the United Kingdom

    International Nuclear Information System (INIS)

    Brima, Eid I.; Haris, Parvez I.; Jenkins, Richard O.; Polya, Dave A.; Gault, Andrew G.; Harrington, Chris F.

    2006-01-01

    Very little is known about arsenic (As) metabolism in healthy populations that are not exposed to high concentrations of As in their food or water. Here we present a study with healthy volunteers from three different ethnic groups, residing in Leicester, UK, which reveals statistically significant differences in the levels of total As in urine and fingernail samples. Urine (n = 63), hair (n = 36) and fingernail (n = 36) samples from Asians, Somali Black-Africans and Whites were analysed using inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectroscopy (GF-AAS). The results clearly show that the total concentrations of As in urine and fingernail samples of a Somali Black-African population (urine 7.2 μg/g creatinine; fingernails 723.1 μg/kg) are significantly (P 0.05) in the level of As in the hair samples from these three groups; Somali Black-Africans (116.0 μg/kg), Asians (117.4 μg/kg) and Whites (141.2 μg/kg). Significantly different levels of total As in fingernail and urine and a higher percentage of urinary DMA in the Somali Black-Africans are suggestive of a different pattern of As metabolism in this ethnic group

  17. Trace elements in scalp hair and fingernails as biomarkers in clinical studies

    Directory of Open Access Journals (Sweden)

    Awad Abdalla Momen

    2015-01-01

    Full Text Available Context: There are accumulating evidences that the metabolism of several trace elements might have specific roles in clinical disorders and the pathogenesis of many diseases, such as diabetes mellitus (DM and hypertension (HT. Objectives: To validate the analytical procedure and compare the levels of Cd, Cr, Cu, Pb, and Zn in scalp hair (SH and fingernails (FN of patients. Furthermore, to prove that human tissues such as hair and nails are useful in the studies pertaining to chronic body exposure and good biomarkers in clinical studies. Setting and Design: Inductively coupled plasma optical emission spectroscopy operating conditions were carefully selected and well-optimised in order to maximise the sensitivity for the desired elements and to obtain the best precision and accuracy. Factors affecting analytical and biological variability of the concentrations under study were discussed and carefully optimised. Materials and Methods: Totally, 160 samples of SH and 130 FN were collected from occupants of urban population from different districts adjacent to Taif city, Kingdom of Saudi Arabia. Different analytical procedures were investigated, and the most reliable one was developed and validated. Method Validity: The validity of the method was checked by standard addition method. The recoveries were in the range of 96.2-105.7%. Results: Cd, Cr, Cu, and Pb levels in SH were significantly higher in DM and HT compared to control groups, whereas, Zn was significantly lower. Cd and Pb levels in FN were significantly higher in DM and HT, whereas, Cr and Zn were lower, and Cu was in the same levels as compared to the control group. Conclusion: These findings may be consistent with those obtained in other studies, confirming that the deficiency and efficiency of trace elements play a role in clinical disorders and the pathogenesis of many diseases.

  18. Ancient clam gardens, traditional management portfolios, and the resilience of coupled human-ocean systems

    Directory of Open Access Journals (Sweden)

    Julia Jackley

    2016-12-01

    Full Text Available Indigenous communities have actively managed their environments for millennia using a diversity of resource use and conservation strategies. Clam gardens, ancient rock-walled intertidal beach terraces, represent one example of an early mariculture technology that may have been used to improve food security and confer resilience to coupled human-ocean systems. We surveyed a coastal landscape for evidence of past resource use and management to gain insight into ancient resource stewardship practices on the central coast of British Columbia, Canada. We found that clam gardens are embedded within a diverse portfolio of resource use and management strategies and were likely one component of a larger, complex resource management system. We compared clam diversity, density, recruitment, and biomass in three clam gardens and three unmodified nonwalled beaches. Evidence suggests that butter clams (Saxidomus gigantea had 1.96 times the biomass and 2.44 times the density in clam gardens relative to unmodified beaches. This was due to a reduction in beach slope and thus an increase in the optimal tidal range where clams grow and survive best. The most pronounced differences in butter clam density between nonwalled beaches and clam gardens were found at high tidal elevations at the top of the beach. Finally, clam recruits (0.5-2 mm in length tended to be greater in clam gardens compared to nonwalled beaches and may be attributed to the addition of shell hash by ancient people, which remains on the landscape today. As part of a broader social-ecological system, clam garden sites were among several modifications made by humans that collectively may have conferred resilience to past communities by providing reliable and diverse access to food resources.

  19. Photosymbiotic Giant Clams are Transformers of Solar Flux

    Science.gov (United States)

    2014-01-01

    photosymbiosis. We discovered that the mantle tissue of giant clams, which harbours symbiotic nutrition-providing microalgae , contains a layer of iridescent cells...called iridocytes that serve to distribute photosynthetically productive wavelengths by lateral and forward-scattering of light into the tissue...while back-reflecting non- productive wavelengths with a Bragg mirror. The wavelength- and angle-dependent scattering from the iridocytes is

  20. Self-Inflicted Gingival Injury Due to Habitual Fingernail Scratching: A Case Report with a 1-Year Follow Up

    Science.gov (United States)

    Dilsiz, Alparslan; Aydin, Tugba

    2009-01-01

    Injuries to oral soft-tissues can occur due to accidental, iatrogenic, and factitious traumas. Traumatic lesions, whether chemical, physical, or thermal in nature, are among the most common in the mouth. A type of physical injury to the gingival tissues is self-inflicted. Sometimes the lesions are termed gingivitis artefacta. Self-inflicted gingival injuries in children and adolescents can occur as a result of accidental trauma, premeditated infliction, or chronic habits such as fingernail biting, digit sucking, or sucking on objects such as pens, pencils or pacifiers. The purpose of this case report was to illustrate the destructive nature of the habit and to describe the successful treatment of this case. A 14-year-old girl with moderate pain, gingival bleeding and recession in the anterior mandibulary region was admitted to periodontology clinic. Upon questioning, the patient readily admitted traumatizing her gingiva with her fingernail. Treatment consisted of oral hygiene instruction, mechanical debridement, psychological support and surgical periodontal treatment. Postoperatively, complete root coverage, gains in clinical attachment levels, and highly significant increases in the width of keratinized gingiva were observed. This case report shows that it is possible to treat gingival injury and maintain the periodontal health of a patient with destructive habit. Patient compliance, regular dental follow-ups, and psychological support may be useful in stabilizing the periodontal condition of these patients. Dentists must be aware that self-inflicted gingival injury, although thought to be uncommon, is quite widespread. PMID:19421397

  1. Research and Application of an Automatic Clam Collecting Device

    Directory of Open Access Journals (Sweden)

    Wang Bin

    2017-01-01

    Full Text Available To collect clams automatically and effectively on coastal beach, an automatic clam collecting device was designed. The device consists of a connecting device, a shovelling device, a conveying device, and a filtering device. The mechanical device is designed based on some of the presented devices, such as a blade with slope, a pipelined conveyor belt, planar linkage mechanisms and a ski mechanism. The connecting device is connected to the device body by bolts. The shovelling device adopts a blade with slope, which can reduce the resistance between sandy soil and the device. The transmission device adopts a conveyor belt with a two-stage reducer, which can effectively control the speed of the transmission and avoid the splash of mud. A mesh structure is used for soil filtering, which is designed with a certain slope, thus sandy soil and other impurities fall from the mesh for its own weight. The designed device for clam collecting will improve efficiency and decrease cost effectively.

  2. Infestation of the surf clam Mesodesma donacium by the spionid polychaete Polydora bioccipitalis

    Science.gov (United States)

    Riascos, José M.; Heilmayer, Olaf; Oliva, Marcelo E.; Laudien, Jürgen; Arntz, Wolf E.

    2008-08-01

    The surf clam Mesodesma donacium is an economically important species for Chilean and Peruvian shellfisheries. This clam is often infested by Polydora bioccipitalis, a species belonging to the Spionidae, the most common parasitic polychaete group. To study this association, clams were sampled monthly over a one-year period in northern Chile. Collected clams covered the entire available size range and were classified into four infestation levels in order to study: (1) the relationship between prevalence of infestation ( PI) and host size, (2) the temporal pattern of infestation events related to seasonal temperature changes, and (3) the relationship between infestation, body condition index ( BCI) and gonado-somatic index ( GSI). Additionally, growth rate and digging ability of clams with different infestation levels was studied. A logistic regression model best explained the relationship between PI and host size, with the smallest infested clam being 34 mm long and PI increasing steeply thereafter. Ontogenetic shifts in the habitat of the clam and ontogenetic changes, mainly in shell morphology, seem to explain the sigmoid pattern. Periods of increased shell blistering after infestation by P. bioccipitalis showed a similar seasonal pattern with GSI and BCI of non-infested clams, suggesting either an association between infestation ability and low condition of the clam or common environmental triggers for those factors. Heavily infested clams showed a significant lower BCI, growth rate and digging ability; however, given its low number, they are unlikely to be significant in terms of the local population survival. However, the infestation could play a key role in explaining mass mortality of northern populations during El Niño events, given the latitudinal differences in PI and the fact that infestation ability could be enhanced by increased temperature and facilitated in stressed clams.

  3. Acute toxicity and bioaccumulation of arsenic in freshwater clam Corbicula fluminea.

    Science.gov (United States)

    Liao, Chung-Min; Jau, Sheng-Feng; Chen, Wei-Yu; Lin, Chieh-Ming; Jou, Li-John; Liu, Chen-Wuing; Liao, Vivian Hsiu-Chuan; Chang, Fi-John

    2008-12-01

    Arsenic is a potent human carcinogen of skin, lung, and urinary bladder. Freshwater clam Corbicula fluminea is a commercially important native species in Taiwan. C. fluminea is also a suitable biomonitoring test organism. Little is known, however, about the actual effects of arsenic on C. fluminea. The objectives of this study were to provide information on the acute toxicity and bioaccumulation kinetics of arsenic in C. fluminea. We carried out a 14-day exposure experiment to obtain bioaccumulation parameters. Uptake was very rapid when C. fluminea was first exposed and then slightly decayed during the uptake phase of the experiment and an uptake rate constant of 1.718 +/- 6.70 (mean +/- SE) mL g(-1) d(-1) was estimated. The elimination of arsenic from C. fluminea obeyed first-order depuration kinetics (r(2) = 0.85, p fluminea. This had important implications for dietary exposure of arsenic to humans who eat contaminated clams, because the soft tissue usually constitutes the majority of tissue consumed. The 96-h LC50 value was estimated to be 20.74 (95% CI: 11.74-30.79) mg L(-1) obtained from a 7-day acute toxicity bioassay. We also kinetically linked an acute toxicity model and a Hill sigmoid model to reconstruct an internal effect concentration based dose-response profile to assess the effect of soft tissue arsenic burden on the C. fluminea mortality. This result could be used to support the establishment of an ecological risk assessment to prevent possible ecosystem and human health consequences. 2008 Wiley Periodicals, Inc.

  4. A SOCIAL COST-BENEFIT ANALYSIS OF A SMALL-SCALE CLAM ...

    African Journals Online (AJOL)

    Results from the CBA yielded positive net present values (NPVs) for project options involving live clams being sold on the export market (to Hong Kong) for R24.70 kg-1 and negative NPVs for domestic market options (Johannesburg and Cape Town), where the clam would be sold for R6.50 kg-1. Assuming a discount rate ...

  5. The Stability of the Giant Clam Holobiont over Time and during Bleaching Stress

    KAUST Repository

    Pappas, Melissa

    2017-12-01

    The stability of marine photosymbiotic holobionts has major implications for the future of coral reef communities. This study aims to describe the stability of the Red Sea giant clam holobiont over the duration of one year and during induced bleaching stress under laboratory thermal manipulations. Tridacnid clams of the species Tridacna maxima were sampled at three reef locations near the central Saudi coast of the Red Sea. Associated Symbiodinium of Red Sea giant clams have previously been described to be part of only Clade A, which suggests a strong specificity in the clam-algal partnership, but specific types and potential shifting of types within this clade have not been examined for giant clams. The results from this study confirm that tridacnid symbiont types shift over time and the change between three A1 types suggests a biological and functional significance of two undescribed A1 Symbiodinium types. Experimental bleaching shows that Red Sea giant clams, although exposed to rather hot temperatures naturally, will bleach at 34°C after two weeks, and severely bleached clams likely will not recover. During bleaching, Symbiodinium types shift as well, and shift more drastically than seasonal shifts during the year. This shifting may be an evolved characteristic of the giant clam to aid in surviving major changes in the environment. However, more research is needed to determine if these holobionts are capable of keeping up with the global forecast of warming in reef environments.

  6. Development and validation of an ex vivo electron paramagnetic resonance fingernail bio-dosimetric method

    International Nuclear Information System (INIS)

    He, Xiaoming; Swarts, Steven G.; Marsh, Stephen D.; Demidenko, Eugene; Flood, Ann B.; Grinberg, Oleg; Gui, Jiang; Mariani, Michael; Ruuge, Andres E.; Tipikin, Dmitry; Swartz, Harold M.; Sidabras, Jason W.; Wilcox, Dean E.

    2014-01-01

    There is an imperative need to develop methods that can rapidly and accurately determine individual exposure to radiation for screening (triage) populations and guiding medical treatment in an emergency response to a large-scale radiological/nuclear event. To this end, a number of methods that rely on dose-dependent chemical and/or physical alterations in biomaterials or biological responses are in various stages of development. One such method, ex vivo electron paramagnetic resonance (EPR) nail dosimetry using human nail clippings, is a physical bio-dosimetry technique that takes advantage of a stable radiation-induced signal (RIS) in the keratin matrix of fingernails and toenails. This dosimetry method has the advantages of ubiquitous availability of the dosimetric material, easy and non-invasive sampling, and the potential for immediate and rapid dose assessment. The major challenge for ex vivo EPR nail dosimetry is the overlap of mechanically induced signals and the RIS. The difficulties of analysing the mixed EPR spectra of a clipped irradiated nail were addressed in the work described here. The following key factors lead to successful spectral analysis and dose assessment in ex vivo EPR nail dosimetry: (1) obtaining a thorough understanding of the chemical nature, the decay behaviour, and the microwave power dependence of the EPR signals, as well as the influence of variation in temperature, humidity, water content, and O 2 level; (2) control of the variability among individual samples to achieve consistent shape and kinetics of the EPR spectra; (3) use of correlations between the multiple spectral components; and (4) use of optimised modelling and fitting of the EPR spectra to improve the accuracy and precision of the dose estimates derived from the nail spectra. In the work described here, two large clipped nail datasets were used to test the procedures and the spectral fitting model of the results obtained with it. A 15-donor nail set with 90 nail samples

  7. Assessment of clam ruditapes philippinarum as Heavy metal bioindicators using NMR-based metabolomics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoli; Zhang, Linbao; You, Liping [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China); The Graduate School of Chinese Academy of Sciences, Beijing (China); Yu, Junbao; Cong, Ming; Wang, Qing; Li, Fei; Li, Lianzhen; Zhao, Jianmin; Li, Chenghua; Wu, Huifeng [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China)

    2011-08-15

    There are mainly distributed three pedigrees (White, Liangdao Red, and Zebra) of Manila clam Ruditapes philippinarum in Yantai population along the Bohai marine and coast. However, the biological differences to environmental stressors have been ignored in toxicology studies, which could lead to the distortion of biological interpretations of toxicological effects induced by environmental contaminants. In this study, we applied a system biology approach, metabolomics to compare the metabolic profiles in digestive gland from three pedigrees of clam and characterize and compare the metabolic responses induced by mercury in clam digestive gland tissues to determine a sensitive pedigree of clam as a preferable bioindicator for metal pollution monitoring and toxicology research. The most abundant metabolites, respectively, included branched-chain amino acids, alanine, and arginine in White samples, glutamate, dimethylglycine, and glycine in Zebra clams and acetylcholine, betaine, glucose, and glycogen in Liangdao Red clams. After 48 h exposure of 20 {mu}g L{sup -1} Hg{sup 2+}, the metabolic profiles from the three pedigrees of clams showed differentially significant changes in alanine, glutamate, succinate, taurine, hypotaurine, glycine, arginine, glucose, etc. Our findings indicate the toxicological effects of mercury exposure in Manila clams including the neurotoxicity, disturbances in energetic metabolisms and osmoregulation in the digestive glands and suggest that Liangdao Red pedigree of clam could be a preferable bioindicator for the metal pollution monitoring based on the more sensitive classes of metabolic changes from digestive glands compared with other two (White and Zebra) pedigrees of clams. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Bioaccumulation of gasoline in brackish green algae and popular clams

    Directory of Open Access Journals (Sweden)

    Gihan A. El-Shoubaky

    2016-03-01

    Full Text Available The green algae (Ulva lactuca and Enteromorpha clathrata and the clams (Tapes decussates and Venerupis aurea grow together in Timsah Lake, Suez Canal, Egypt. Our ultimate goal is to validate the bioaccumulation of gasoline in the marine organisms and their behavior after exposure to the pollutant, experimentally. These species were treated with a serial treatment of gasoline (1000, 4000, 16,000 and 64,000 μl in aquaria with brackish sea-water for 72 h. The tested green algae and clams were taken for an analysis of total hydrocarbon accumulation daily. The statistical analysis showed significant differences between the four species and also between the duration of exposure. The accumulation of gasoline in U. lactuca and E. clathrata reached their maximum after 48 h at 1000 and 4000 μl. The highest absorption was registered after 24 h only at 16,000 and at 64,000 μl. U. lactuca recorded complete mortality in 64,000 μl at 72 h whereas E. clathrata registered death at 48 h and 72 h in the same treatment. V. aurea was more sensitive than T. decussates. The accumulation of gasoline reached its maximum in V. aurea after only 24 h in the first treatment while it retarded to 48 h in T. decussates with a lesser accumulation. However, both clam species accumulated the highest amount of petroleum hydrocarbons during the first hour of exposure at the first treatment. In the third and fourth treatments, clams did not accumulate gasoline but began to dispose it from their tissues till it became less than that in the control. Mortality gradually increased with time in each treatment except the last one (64,000 μl in which 100% death of the specimens was observed. In general, the bioaccumulation of gasoline level was in a descending order as follows: U. lactuca > E. clathrata > V. aurea > T. decussates. Their behavior changed from accumulation to detoxification with time and with the increase in pollutant concentration. Generally, these

  9. PCDD/F and dioxin-like PCB bioaccumulation by Manila clam from polluted areas of Venice lagoon (Italy)

    International Nuclear Information System (INIS)

    Sfriso, Adriano; Facca, Chiara; Raccanelli, Stefano

    2014-01-01

    POP bioaccumulation pathways in the clam Tapes philippinarum were examined for two years from juveniles to adult size. Two polluted sites, one with sandy sediment, the other muddy were compared with a reference site characterized by low contamination levels. Juvenile clams coming from a hatchery were reared both on the sediment and in nets suspended at 30 cm from the bottom. POP changes in clam tissue were related to the concentrations recorded in sediments and in the particulate matter during the entire fattening period. Results provided interesting data on the relationships between environmental contamination and bioaccumulation. Contrary to studies on the decontamination times of the clams collected in polluted areas, this work investigates the preferential clam bioaccumulation pathways during growth under different environmental conditions. In general POP bioaccumulation resulted to be correlated to concentrations in SPM rather than in sediments and was higher in S-clams rather than in B-clams. -- Highlights: • PCDD/Fs and dioxin-like PCB accumulation in clam tissues during growth. • Muddy and sandy polluted areas. • How sediment and suspended matter contamination affect clam toxicity. • Clam toxicity and law limits. -- Clam bioaccumulation pathways in polluted areas

  10. PCDD/F and dioxin-like PCB bioaccumulation by Manila clam from polluted areas of Venice lagoon (Italy).

    Science.gov (United States)

    Sfriso, Adriano; Facca, Chiara; Raccanelli, Stefano

    2014-01-01

    POP bioaccumulation pathways in the clam Tapes philippinarum were examined for two years from juveniles to adult size. Two polluted sites, one with sandy sediment, the other muddy were compared with a reference site characterized by low contamination levels. Juvenile clams coming from a hatchery were reared both on the sediment and in nets suspended at 30 cm from the bottom. POP changes in clam tissue were related to the concentrations recorded in sediments and in the particulate matter during the entire fattening period. Results provided interesting data on the relationships between environmental contamination and bioaccumulation. Contrary to studies on the decontamination times of the clams collected in polluted areas, this work investigates the preferential clam bioaccumulation pathways during growth under different environmental conditions. In general POP bioaccumulation resulted to be correlated to concentrations in SPM rather than in sediments and was higher in S-clams rather than in B-clams. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Freshwater Clam Extract Ameliorates Triglyceride and Cholesterol Metabolism through the Expression of Genes Involved in Hepatic Lipogenesis and Cholesterol Degradation in Rats

    Directory of Open Access Journals (Sweden)

    Thomas Laurent

    2013-01-01

    Full Text Available The freshwater clam (Corbicula spp. is a popular edible bivalve and has been used as a folk remedy for liver disease in Asia. As a Chinese traditional medicine, it is said that freshwater clam ameliorates alcoholic intoxication and cholestasis. In this study, to estimate the practical benefit of freshwater clam extract (FCE, we compared the effects of FCE and soy protein isolate (SPI on triglyceride and cholesterol metabolism in rats. FCE and SPI lowered serum cholesterol, and FCE tended to reduce serum triglycerides. FCE enhanced fecal sterol excretion and hepatic mRNA levels of CYP7A1 and ABCG5 more substantially than SPI; however, both diets reduced hepatic cholesterol. Both of the diets similarly suppressed liver lipids improved Δ9-desaturated fatty acid profile, and FCE was associated with a reduction in FAS and SCD1 mRNA levels. Hepatic transcriptome analysis revealed that inhibition of lipogenesis-related gene expression may contribute to downregulation of hepatic triglycerides by FCE. FCE would have better potential benefits for preventing metabolic disorders, through greater improvement of metabolism of triglycerides and cholesterol, likely through a mechanism similar to SPI.

  12. Great Lakes clams find refuge from zebra mussels in restored, lake-connected marsh (Ohio)

    Science.gov (United States)

    Nichols, S. Jerrine; Wilcox, Douglas A.

    2004-01-01

    Since the early 1990s, more than 95 percent of the freshwater clams once found in Lake Erie have died due to the exotic zebara mussel (Dreissena polymorpha). Zebra mussels attach themselves to native clams in large numbers, impeding the ability of the clams to eat and burrow. However, in 1996, we discovered a population of native clams in Metzger Marsh in western Lake Erie (about 50 miles [80 km] east of Toledo) that were thriving despite the longtime presence of zebra mussel in surrounding waters. At that time, Metzger Marsh was undergoing extensive restoration, including construction of a dike to replace the eroded barrier beach and of a water-control structure to maintain hydrologic connections with the lake (Wilcox and Whillans 1999). The restoration plan called for a drawdown of water levels to promote plant growth from the seedbank -- a process that would also destroy most of the clam population. State and federal resource managers recommended removing as many clams as possible to a site that was isolated from zebra mussels, and then returning them to the marsh after it was restored. We removed about 7,000 native clams in 1996 and moved them back to Metzger Marsh in 1999.

  13. Bacciger bacciger (Trematoda: Fellodistomidae) infection effects on wedge clam Donax trunculus condition.

    Science.gov (United States)

    de Montaudouin, Xavier; Bazairi, Hocein; Mlik, Karima Ait; Gonzalez, Patrice

    2014-10-16

    Wedge clams Donax trunculus inhabit high-energy environments along sandy coasts of the northeastern Atlantic Ocean and the Mediterranean Sea. Two sites were sampled monthly, one in Morocco (Mehdia), where the density was normal, and one in France (Biscarosse), where the density was very low. We tested the hypothesis that the difference in density between the sites was related to infection by the trematode parasite Bacciger bacciger. Identity of both the parasite and the host were verified using anatomical and molecular criteria. Parasite prevalence (i.e. the percentage of parasitized clams) was almost 3 times higher at Biscarosse. At this site, overall prevalence reached 32% in July and was correlated with the migration of several individuals (with a prevalence of 88%) to the sediment surface. After this peak, prevalence decreased rapidly, suggesting death of parasitized clams. The deleterious effect of B. bacciger on wedge clams was also supported by our calculations indicating that the weight of the parasite made up to 56% of the total weight of the parasitized clams. However, condition indices of trematode-free clams were also lower in Biscarosse than in Mehdia or other sites, suggesting that other factors such as pollutants or microparasites (Microcytos sp.) may alter wedge clam population fitness in Biscarosse.

  14. The antioxidant potential of the New Zealand surf clams.

    Science.gov (United States)

    Odeleye, Tinu; Li, Yan; White, William Lindsey; Nie, Shaoping; Chen, Shuping; Wang, Junqiao; Lu, Jun

    2016-08-01

    The antioxidant action of three New Zealand surf clams was evaluated for the first time. Aqueous (cd) and ethanolic extracts from Diamond shell - Crassula aequilatera, Storm shell - Mactra murchisoni, and Tua tua - Paphies donacina were studied for their antioxidant potentials using two in vitro assays. The ethanolic extracts were further fractioned into four parts; petroleum ether (pe), ethyl acetate (ea), n-butanol (nb), and the final aqueous fraction (w). Comparing among all fractions tested, the ea fraction of P. donacina showed the strongest free radical scavenging power, with a radical scavenging activity of 76.14% at 20μg/mL. The ea fraction of C. aequilatera had the highest copper reducing activity with an absorbance of 1.596 at 20μg/mL. Results from this study suggest that some bioactive compounds with significant antioxidant effects may exist in the New Zealand surf clams, and could potentially reduce oxidative stress to deliver health benefits or to produce functional foods. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Concentrations of organotin compounds in sediment and clams collected from coastal areas in Vietnam

    International Nuclear Information System (INIS)

    Midorikawa, Sayaka; Arai, Takaomi; Harino, Hiroya; Ohji, Madoka; Nguyen Duc Cu; Miyazaki, Nobuyuki

    2004-01-01

    Levels of butyltin (BT) and phenyltin (PT) compounds were determined in sediments and clam Meretrix spp. collected from north and central coastal areas in Vietnam. Concentrations of TBT in sediments ranged from 0.89 to 34 ng g -1 dry wt and those in clams ranged from 1.4 to 56 ng g -1 wet wt. The levels of TBT in sediments and clams from Vietnam were within limits reported from other countries. Further, the TBT level in clams was lower than the tolerable average residue level (TARL) estimated based on tolerable daily intake (TDI). Trace amounts of PTs were also found in both sediment and clam samples. In sediments from north and central Vietnam, the concentrations of TBT were highest in the order of Hue (28 ng g -1 dry wt), Cua Luc (15 ng g -1 dry wt), Sam Son (6.3 ng g -1 dry wt), and Tra Co (5.5 ng g -1 dry wt). Among the clams from north and central Vietnam, the levels of TBT in clams from Cua Luc were dramatically high at 47 ng g -1 wet wt. TBT formed the principal butyltin species in sediment at all sites studied. The ratios of TBT in sediment were higher among BT compounds at all study sites. Of total BTs, TBT was the dominant species in clams from almost all sites studied. In spatial distribution, TPT showed a pattern similar to TBT, suggesting the use of TPT as an antifouling paint. The partition coefficient between sediment and calms was calculated. The partition coefficients of TBT and TPT were 2.01 (0.56-5.5) and 9.23 (3.1-20), respectively. These results show that sediment-bound TBT is a source of contamination to clams in addition to dissolved TBT

  16. Annual harvests of Corbicula populations prevent clogging of nuclear reactor heat exchangers

    International Nuclear Information System (INIS)

    Harvey, R.S.

    1983-01-01

    An annual program for removal of millions of Corbicula from upstream cooling water basins has prevented reclogging of nuclear reactor heat exchanger distributor plates at the Savannah River Plant during the past seven years. There are nine 32-megaliter basins in the three operating reactor areas where some settling of particulates occurs before cooling water is passed through screens in route to heat exchangers. Annual cleanings keep silt/clam substrate levels low and clam sizes small. Data are presented on the size/age distribution for clams recolonizing basins between cleanings

  17. Recolonization of reactor cooling water system by the Asiatic clam Corbicula fluminea

    International Nuclear Information System (INIS)

    Harvey, R.S.

    1978-01-01

    Recolonization rates for the Asiatic clam Corbicula fluminea ranged from 3.0 to 5.6 metric tons per year in cooling water basins for a nuclear production reactor at the Savannah River Plant. However, a 10-month cleaning cycle for each basin (flow area, 6100 m 2 ) keeps the depth of the silt/clam layer low. With this cleaning frequency, Corbicula are not reaching heat exchangers at sufficient size or in sufficient numbers to restrict flow. Data are presented on the size/age distribution for clams recolonizing cooling water basins between cleanings

  18. The asiatic clam, Corbicula fluminea (Müller), in the tidal Potomac River, Maryland

    Science.gov (United States)

    Dresler, Paul V.; Cory, Robert L.

    1980-01-01

    The Asiatic clam,Corbicula fluminea (Müller), has extended its range to include the tidal fresh-water portion of the Potomac River, Maryland. Though patchily distributed, the clams have attained densities of 665 m−2. Size-class distributions indicate that the clams first appeared in 1975. About 90% of the population belong to year-class I and were less than 12 mm in length. Elsewhere, this species has created severe water quality problems; it should be closely watched in the Potomac.

  19. Prevention

    Science.gov (United States)

    ... Error processing SSI file About Heart Disease & Stroke Prevention Heart disease and stroke are an epidemic in ... secondhand smoke. Barriers to Effective Heart Disease & Stroke Prevention Many people with key risk factors for heart ...

  20. Using hair and fingernails in binary logistic regression for bio-monitoring of heavy metals/metalloid in groundwater in intensively agricultural areas, Thailand.

    Science.gov (United States)

    Wongsasuluk, Pokkate; Chotpantarat, Srilert; Siriwong, Wattasit; Robson, Mark

    2018-04-01

    In this study, the hair and fingernails of the local people in an intensively cultivated agricultural area in Ubon Ratchathani province, Thailand, were used as biomarkers of exposure to arsenic (As) and heavy metals. The study area has shallow acidic groundwater that is contaminated with As and heavy metals. The local people often consume this shallow groundwater; thus, they are exposed to As and heavy metals. Hair and fingernail samples were collected to characterize the differences between shallow groundwater drinking (SGWD) and tap water drinking (TWD) residents. The concentrations of As and the heavy metals Cd, Pb and Hg were significantly higher in the hair samples from the SGWD group than those from the TWD group, especially for As (0.020-0.571 vs. 0.024-0.359µg/g) and Cd (0.009-0.575 vs. 0.013-0.230µg/g). Similarly, the concentrations of As and the heavy metals in the fingernail samples collected from the SGWD group were larger than those of the TWD group, especially for As (0.039-2.440µg/g vs. 0.049-0.806µg/g). The χ 2 statistic and binary logistic regression were used to find the associated factors and assess the associated probabilities. The regression results show that the factors associated with the concentrations of As and the heavy metals in the hair samples were drinking water source, rate of water consumption, gender, bathing water source, education, smoking and underlying disease, whereas the factors associated with the concentrations of these species in the fingernail samples were drinking water source, gender, occupation, work hours per day, alcohol consumption, and the use of pesticides. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Risk-based probabilistic approach to assess the impact of false mussel invasions on farmed hard clams.

    Science.gov (United States)

    Liao, Chung-Min; Ju, Yun-Ru; Chio, Chia-Pin; Chen, Wei-Yu

    2010-02-01

    The purpose of this article is to provide a risk-based predictive model to assess the impact of false mussel Mytilopsis sallei invasions on hard clam Meretrix lusoria farms in the southwestern region of Taiwan. The actual spread of invasive false mussel was predicted by using analytical models based on advection-diffusion and gravity models. The proportion of hard clam colonized and infestation by false mussel were used to characterize risk estimates. A mortality model was parameterized to assess hard clam mortality risk characterized by false mussel density and infestation intensity. The published data were reanalyzed to parameterize a predictive threshold model described by a cumulative Weibull distribution function that can be used to estimate the exceeding thresholds of proportion of hard clam colonized and infestation. Results indicated that the infestation thresholds were 2-17 ind clam(-1) for adult hard clams, whereas 4 ind clam(-1) for nursery hard clams. The average colonization thresholds were estimated to be 81-89% for cultivated and nursery hard clam farms, respectively. Our results indicated that false mussel density and infestation, which caused 50% hard clam mortality, were estimated to be 2,812 ind m(-2) and 31 ind clam(-1), respectively. This study further indicated that hard clam farms that are close to the coastal area have at least 50% probability for 43% mortality caused by infestation. This study highlighted that a probabilistic risk-based framework characterized by probability distributions and risk curves is an effective representation of scientific assessments for farmed hard clam in response to the nonnative false mussel invasion.

  2. 76 FR 65180 - Proposed Information Collection; Comment Request; Application to Shuck Surf Clams/Ocean Quahogs...

    Science.gov (United States)

    2011-10-20

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration Proposed Information Collection; Comment Request; Application to Shuck Surf Clams/Ocean Quahogs at Sea AGENCY: National Oceanic and Atmospheric Administration...

  3. Total reflection X-ray spectrometry (TXRF) for trace elements assessment in edible clams.

    Science.gov (United States)

    Marguí, Eva; de Fátima Marques, Alexandra; de Lurdes Prisal, Maria; Hidalgo, Manuela; Queralt, Ignasi; Carvalho, Maria Luisa

    2014-01-01

    The present contribution presents a preliminary investigation of the chemical composition with respect to major, minor, trace, and ultratrace elements in several clam species that are frequently used for human consumption in Portuguese markets and worldwide. In order to use a simple and rapid analytical methodology for clam analysis, energy dispersive X-ray fluorescence (EDXRF) spectrometry and total reflection X-ray fluorescence (TXRF) spectrometry were selected as analytical techniques. The analytical capabilities of TXRF spectrometry were evaluated for the determination of minor and trace elements in commercial edible clams. We compared the direct analysis of powdered suspensions (using different sample amounts and dispersant agents) with the analysis of the digested samples for trace element determination. Inductively coupled plasma mass spectrometry analysis of clam digests was also performed to evaluate the analytical possibilities of TXRF spectrometry for trace and ultratrace analysis.

  4. Ionic and Amino Acid Regulation in Hard Clam (Meretrix lusoria in Response to Salinity Challenges

    Directory of Open Access Journals (Sweden)

    Chia-Hao Lin

    2016-08-01

    Full Text Available Most marine mollusks are osmoconformers, in that, their body fluid osmolality changes in the direction of the change in environmental salinity. Marine mollusks exhibit a number of osmoregulatory mechanisms to cope with either hypo- or hyperosmotic stress. The effects of changes in salinity on the osmoregulatory mechanisms of the hard clam (Meretrix lusoria, an economically important species of marine bivalve for Taiwan have not been determined. In this study, we examined the effect of exposure to hypo (10‰- and hyper (35‰-osmotic salinity on hard clams raised at their natural salinity (20‰. The osmolality, [Na+], and [Cl-] of the hard clam hemolymph were changed in the same direction as the surrounding salinity. Further, the contents of total free amino acids including taurine in the gills and mantles were significantly upregulated in hard clam with increasing salinity. The gill Na+,K+-ATPase (NKA activity, the important enzyme regulating cellular inorganic ions, was not affected by the changed salinity. Mantle NKA activity, however, was stimulated in the 35‰ SW treatment. The taurine transporter (TAUT is related to the regulation of intracellular contents of taurine, the dominant osmolyte. Herein, a TAUT gene of hard clam was cloned and a TAUT antibody was derived for the immunoblotting. The TAUT mRNA expression of the mantle in hard clam was significantly stimulated in 35‰ SW, but protein expression was not modulated by the changed salinity. In gills of the hard clam with 10‰ SW, both TAUT mRNA and protein expressions were significantly stimulated, and it may reflect a feedback regulation from the decreased gills taurine content under long-term hypoosmotic acclimation. These findings suggest that TAUT expression is regulated differently in gills and mantles following exposure to alterations in environmental salinity. Taken together, this study used the physiological, biochemical and molecular approaches to simultaneously explore

  5. Using the Asian clam as an indicator of microplastic pollution in freshwater ecosystems.

    Science.gov (United States)

    Su, Lei; Cai, Huiwen; Kolandhasamy, Prabhu; Wu, Chenxi; Rochman, Chelsea M; Shi, Huahong

    2018-03-01

    Bioindicators play an important role in understanding pollution levels, bioavailability and the ecological risks of contaminants. Several bioindicators have been suggested for understanding microplastic in the marine environment. A bioindicator for microplastics in the freshwater environment does not exist. In our previous studies, we found a high frequency of microplastic pollution in the Asian clam (Corbicula fluminea) in Taihu Lake, China. In the present study, we conducted a large-scale survey of microplastic pollution in Asian clams, water and sediment from 21 sites in the Middle-Lower Yangtze River Basin from August to October of 2016. The Asian clam was available in all sites, which included diverse freshwater systems such as lakes, rivers and estuaries. Microplastics were found at concentrations ranging from 0.3-4.9 items/g (or 0.4-5.0 items/individual) in clams, 0.5-3.1 items/L in water and 15-160 items/kg in sediment. Microfibers were the most dominant types of microplastics found, accounting for 60-100% in clams across all sampling sites. The size of microplastics ranged from 0.021-4.83 mm, and microplastics in the range of 0.25-1 mm were dominant. The abundance, size distribution and color patterns of microplastics in clams more closely resembled those in sediment than in water. Because microplastic pollution in the Asian clam reflected the variability of microplastic pollution in the freshwater environments, we demonstrated the Asian clam as an bioindicator of microplastic pollution in freshwater systems, particularly for sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Biochemical changes during larval development in the short neck clam, Paphia malabarica Chemnitz

    Digital Repository Service at National Institute of Oceanography (India)

    Gireesh, R.; Biju, A.; Muthiah, P.

    in Ashtamudi estuary. It is a major ¢shery in Kerala coasts (Appukuttan1993,1996) and is commercially exploited for both meat as food and shell as raw material for industrial applications Aquaculture Research, 2009, 40, 1510^1515 doi: 10.1111/j.1365... on this clam, and their commercial culture has shown considerable promise. Traditionally, clam farming depends on naturalseedsthatarecollectedfromintertidal zones, which is labour intensive, often unreliable and limited only to a short season. Moreover...

  7. Influence of non-metal inclusions on mechanical properties of Clam steel

    International Nuclear Information System (INIS)

    Liu, S.; Huang, Q.; Li, C.

    2007-01-01

    Full text of publication follows: With good irradiation swelling resistance, thermo-physical and thermo-mechanical properties, the RAFMs (Reduced Activation Ferritic / Martensitic steels) have been considered as the primary candidate structural materials for application in fusion systems in the near future. The China Low Activation Martensitic steel (CLAM) based on the nominal compositions of 9Cr1.5WVTa is being developed in Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) under wide collaboration with many other institutes and universities in domestic and overseas. The heat treatment of CLAM is quenching at 980 deg. C for 30 minutes and then cooled by air or water and tempering at 760 deg. C for 90 minutes and then cooled by air. Mechanical properties of CLAM were strongly affected by the size and distribution of non-metal inclusions as most steels, and its effects on mechanical properties of CLAM steel has been investigated. The evaluation of the non-metallic inclusions in CLAM has been done by optical microscopy observation, electron microscopy observation and Energy Dispersive X-ray Spectroscopy (EDS) analysis. The results showed that most of the non-metal inclusions in CLAM were brittle alumina phase with large size and non-uniform distribution and those were no good to the mechanical properties of CLAM. So electroslag remelting process was chosen to remelt the ingot which was smelted previously by vacuum induction furnace. Inclusion detection by optical microscopy showed that both of the dimensions and quantity of the inclusions decreased and their distributions became more uniform compared with the case before. And the tensile tests and Charpy V-notch impact tests indicated that electroslag remelting improved the tensile properties and impact toughness of CLAM steel. (authors)

  8. Addressing Sustainability of Clam Farming in the Venice Lagoon

    Directory of Open Access Journals (Sweden)

    Donata Melaku Canu

    2011-09-01

    According to the System Approach Framework (SAF, based on previous studies and stakeholder interactions, we developed a model integrating ecological, social, and economic (ESE aspects. We chose the aspects necessary to represent the essential dynamics of major ecological, social, and economic clam farming system components to project the consequences of implementing alternative management policies and to address the ecological and social carrying capacity. Results of the simulations suggest that a properly managed farming system can sustain an acceptable income and support the local community, while reducing negative environmental impacts, social conflicts, and consumer health risks and improving system resilience. The results highlight the importance of an interdisciplinary, participatory, and adaptive approach in planning the management of this important renewable resource.

  9. Effects of water temperature change on immune function in surf clams, Mactra veneriformis (Bivalvia: Mactridae).

    Science.gov (United States)

    Yu, Jin Ha; Song, Jae Hee; Choi, Min Chul; Park, Sung Woo

    2009-09-01

    Surf clam, Mactra veneriformis is one of the crucial fishery resources in Korea. This study was performed to examine the immune functions of the surf clam under the stress of water temperature changes at 10 degrees C, 20 degrees C or 30 degrees C for 24h. Viable bacterial counts (VBC), total haemocyte count (THC), phagocytic activity, lysozyme activity, NRR times and SOD activity were assessed in three different water temperature groups. Clams held at 10 degrees C decreased in THC, lysozyme activity and NRR times, but phagocytic activity was increased. The highest temperature (30 degrees C) significantly increased in THC, whereas it decreased in phagocytic activity, lysozyme activity and NRR times. In clams maintained at 20 degrees C, phagocytic activity, lysozyme activity and NRR times were increased whereas THC was somewhat decreased with respect to clams held at 30 degrees C. However, water temperature changes did not elicit any alteration of VBC and SOD activity. The present study demonstrates that acute water temperature change affects the haemocytic and haemolymphatic functions, reducing immunosurveillance in stressed surf clam, M. veneriformis.

  10. Occurrence of Perkinsus olseni in the Venus clam Protothaca jedoensis in Korean waters.

    Science.gov (United States)

    Park, Kyung-Il; Ngo, Thao T T; Choi, Sang-Duk; Cho, Moonjae; Choi, Kwang-Sik

    2006-10-01

    This is the first report of the occurrence of Perkinsus olseni in the Venus clam Protothaca jedoensis off the western and southern coasts of South Korea. Histological observations revealed Perkinsus-like organisms in the mantle, gills, digestive tubules, and gonad. Haemocytic infiltration and tissue necrosis were also observed in heavily infected clams. Hypnospore formation of the Perkinsus-like organism was confirmed with Ray's fluid thioglycollate medium assay (RFTM). When incubated in filtered and aerated seawater, the hypnospore gave rise to cell division and subsequently discharged hundreds of motile zoospores. Genus- and species-specific polymerase chain reaction (PCR) assays and the DNA sequences of the internal transcribed spacer region (ITS) of the Perkinsus sp. isolated from the Venus clam were identical to those of P. olseni reported from the Manila clam Venerupis (=Ruditapes)philippinarum. Based on the DNA sequences and microscopic data, the Perkinsus-like pathogen isolated from P. jedoensis was identified as P. olseni, which parasitizes the Manila clam in European and Asian waters and Haliotis rubra (abalone) in Australian waters. The prevalence and infection intensity of a clam population collected from Yosu, Korea, was determined using RFTM and Choi's 2M NaOH digestion technique. The intensities averaged 10,768 and 7438 Perkinsus cells per gram tissue in 2003 and 2004, and the prevalence ranged from 37.0 to 53.9%, respectively.

  11. A dynamic artificial clam (Corbicula fluminea) allows parsimony on-line measurement of waterborne metals

    Energy Technology Data Exchange (ETDEWEB)

    Jou, L.-J. [Ecotoxicological Modeling Center, Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan 10617 (China); Department of Biomechatronic Engineering, National Ilan University, Ilan, Taiwan 260 (China); Liao, C.-M. [Ecotoxicological Modeling Center, Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan 10617 (China)]. E-mail: cmliao@ntu.edu.tw

    2006-11-15

    We introduce a novel on-line biomonitoring system based on a valvometric conversion technique for clam Corbicula fluminea, allowing for rapid, continuous, and ecological relevant water quality control. Our model builds upon the basic principles of biological early warning system model in two ways. We first adopted a risk-based methodology to build a dynamic artificial clam for simulating how the bivalve closure rhythm in response to waterborne copper (Cu) and cadmium (Cd). Secondly, we integrated a probabilistic model associated with the time-varying dose-response relationships of valve closing behavior into the mechanisms of a dynamic artificial clam, allowing estimation of the time-varying waterborne Cu/Cd concentrations for on-line providing the outcomes of the toxicity detection technique. Measurements with Cu/Cd were performed and the calculated EC50 values were compared with published data for the valve movement test with C. fluminea. This proposed dynamic artificial clam provides a better quantitative understanding of on-line biomonitoring measurements of waterborne metals and may foster applications in clam farm management strategy and ecotoxicological risk assessment. - A dynamic artificial clam allows on-line biomonitoring waterborne metal toxicity.

  12. Evaluating sublethal indicators of stress in Asiatic clams (Corbicula fluminea) caged in an urban stream

    Energy Technology Data Exchange (ETDEWEB)

    Black, M.C.; Belin, J.I. [Univ. of Georgia, Athens, GA (United States). College of Agricultural and Environmental Sciences

    1998-12-31

    Freshwater bivalves have been used extensively to monitor chemical accumulation in field exposures, although little information is available on the use of biomarker measurements in field exposures with bivalves. DNA strand breakage, growth rate, condition index and percentage tissue water were measured in freshwater Asiatic clams (Corbicula fluminea) exposed in-situ in a stream that receives urban and industrial stormwater runoff and in a non-impacted reference stream. After 4 weeks exposure, DNA strand lengths in foot tissue from Trail Creek-exposed clams were significantly shorter than DNA from reference clams. These results suggest a reduction in DNA integrity in Trail Creek-exposed clams, possibly indicating exposure to genotoxic chemicals. No significant differences were observed in the growth rates of clams. However, a significant inverse relationship was detected between condition index and % tissue water for all clams. Furthermore, site-specific differences in percentage tissue water and condition indices were observed after 2 and 10 weeks exposure. For this study DNA strand breakage, condition indices, and tissue hydration appear to be more sensitive indicators of sublethal toxicity than growth.

  13. Microplastic Ingestion by Wild and Cultured Manila Clams (Venerupis philippinarum) from Baynes Sound, British Columbia.

    Science.gov (United States)

    Davidson, Katie; Dudas, Sarah E

    2016-08-01

    Microplastics, plastic particles microplastics are small, they are available to many filter-feeding organisms, which can then be consumed by higher trophic level organisms, including humans. This study documents the quantity of microplastics present in wild and cultured Manila clams (Venerupis philippinarum). Three active shellfish farms and three reference beaches (i.e., non-shellfish farm sites) in Baynes Sound, British Columbia were chosen to examine the microplastic concentrations in wild and cultured Manila clams. Microplastics were isolated using a nitric acid digestion technique and enumerated from 54 clams (27 farmed and 27 non-farmed). Qualitative attributes, such as colour and microplastic type (fiber, fragment, or film) also were recorded. There was no significant difference (F = 1.29; df = 1,4; P = 0.289) between microplastic concentrations in cultured and wild clams. Microplastic concentrations ranged from 0.07 to 5.47 particles/g (from reference beach and shellfish farm clams, respectively). Fibers were the dominant microplastic (90 %); colourless and dark gray fibers were the most common colours observed (36 and 26 %, respectively). Although this indicates that microplastics are definitely present in seafood consumed by humans, shellfish aquaculture operations do not appear to be increasing microplastic concentrations in farmed clams in this region.

  14. Mercury and iron uptake by cytosomes in mantle epithelial cells of quahog clams (Mercenaria mercenaria) exposed to mercury

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, B.A. (National Inst. of Environmental Health Sciences, Research Triangle Park, NC); Wolfe, D.A.; Hettler, W.F.

    1975-10-01

    Specimens of the quahog clam Mercenaria mercenaria were placed in sea water containing mercury (Hg/sup + +/) concentrations of 0.1, 1, and 10 parts per million (ppM) for 6 days. A dose-related increase of electron dense cytosomes was observed by electron microscopy in mantle tentacle epithelial cells of mercury-treated clams. Energy dispersive x-ray microanalysis of these cytosomes disclosed the presence of high iron concentrations in relation to mercury. Analysis of mantle fringes from the same clams by atomic absorption spectroscopy showed marked changes in tissue iron levels of mercury-treated clams in comparison to controls.

  15. Prevention

    Science.gov (United States)

    ... Contact Aging & Health A to Z Find a Geriatrics Healthcare Professional Medications & Older Adults Making Your Wishes ... Prevention Hearing Loss Heart Attack High Blood Pressure Nutrition Osteoporosis Shingles Skin Cancer Related News Quitting Smoking, ...

  16. Recovery of Waterborne Cryptosporidium parvum Oocysts by Freshwater Benthic Clams (Corbicula fluminea)

    Science.gov (United States)

    Graczyk, Thaddeus K.; Fayer, Ronald; Cranfield, Michael R.; Conn, David Bruce

    1998-01-01

    Asian freshwater clams, Corbicula fluminea, exposed for 24 h to 38 liters of water contaminated with infectious Cryptosporidium parvum oocysts (1.00 × 106 oocysts/liter; approximately 1.9 × 105 oocysts/clam) were examined (hemolymph, gills, gastrointestinal [GI] tract, and feces) on days 1, 2, 3, 7, and 14 postexposure (PE). No oocysts were detected in the water 24 h after the contamination event. The percentage of oocyst-containing clams varied from 20 to 100%, depending on the type of tissue examined and the technique used—acid-fast stain (AFS) or immunofluorescent antibody (IFA). The oocysts were found in clam tissues and feces on days 1 through 14 PE; the oocysts extracted from the tissues on day 7 PE were infectious for neonatal BALB/c mice. Overall, the highest number of positive samples was obtained when gills and GI tracts were processed with IFA (prevalence, 97.5%). A comparison of the relative oocyst numbers indicated that overall, 58.3% of the oocysts were found in clam tissues and 41.7% were found in feces when IFA was used; when AFS was used, the values were 51.9 and 48.1%, respectively. Clam-released oocysts were always surrounded by feces; no free oocysts or oocysts disassociated from fecal matter were observed. The results indicate that these benthic freshwater clams are capable of recovery and sedimentation of waterborne C. parvum oocysts. To optimize the detection of C. parvum oocysts in C. fluminea tissue, it is recommended that gill and GI tract samples be screened with IFA (such as that in the commercially available MERIFLUOR test kit). PMID:9464376

  17. Distribution and winter survival health of Asian clams, Corbicula fluminea, in the St. Clair River, Michigan

    Science.gov (United States)

    French, John R. P.; Schloesser, Don W.

    1996-01-01

    We studied the distribution and winter survival of the Asian clam, Corbicula fluminea, in the St. Clair River from the fall of 1988 to the spring of 1990. Between fall of 1988 and spring of 1989, distribution of Corbicula was extended from 5.5 to 11.5 km downstream from an electric power plant. However, total abundance of clams decreased during the winter. By fall of 1989, Corbicula was found 14.5 km from the power plant, and the mean density of clams was 27 individuals/m2. Between fall of 1989 and spring of 1990, distribution was reduced to 7.5 km from the power plant and abundance decreased 97%. During the winter of 1988-1989, we collected clams monthly from one station 2.2 km from the power plant, and we observed that clams survived the harsh winter for two months after the water temperature dropped about 1.5°C below the reported lethal level for Corbicula in midwinter. During the winer of 1989-1990, we held clams at the sediment-water interface in enclosures, and we observed that condition indices (dry body weight; dry shell weight) of clams remained stable (mean = 0.05 ± 0.01) in December and January and then declined significantly (p Corbicula in the St. Clair River. In contrast to the rapid geographic spread and population increases in the southern United States, Corbicula likely will not spread rapidly throughout the Great Lakes beyond shoreline thermal refugia of heated-water discharge plumes from power plants.

  18. Anaerobic methanotrophic community of a 5346-m-deep vesicomyid clam colony in the Japan Trench.

    Science.gov (United States)

    Felden, J; Ruff, S E; Ertefai, T; Inagaki, F; Hinrichs, K-U; Wenzhöfer, F

    2014-05-01

    Vesicomyidae clams harbor sulfide-oxidizing endosymbionts and are typical members of cold seep communities where active venting of fluids and gases takes place. We investigated the central biogeochemical processes that supported a vesicomyid clam colony as part of a locally restricted seep community in the Japan Trench at 5346 m water depth, one of the deepest seep settings studied to date. An integrated approach of biogeochemical and molecular ecological techniques was used combining in situ and ex situ measurements. In sediment of the clam colony, low sulfate reduction rates (maximum 128 nmol mL(-1) day(-1)) were coupled to the anaerobic oxidation of methane. They were observed over a depth range of 15 cm, caused by active transport of sulfate due to bioturbation of the vesicomyid clams. A distinct separation between the seep and the surrounding seafloor was shown by steep horizontal geochemical gradients and pronounced microbial community shifts. The sediment below the clam colony was dominated by anaerobic methanotrophic archaea (ANME-2c) and sulfate-reducing Desulfobulbaceae (SEEP-SRB-3, SEEP-SRB-4). Aerobic methanotrophic bacteria were not detected in the sediment, and the oxidation of sulfide seemed to be carried out chemolithoautotrophically by Sulfurovum species. Thus, major redox processes were mediated by distinct subgroups of seep-related microorganisms that might have been selected by this specific abyssal seep environment. Fluid flow and microbial activity were low but sufficient to support the clam community over decades and to build up high biomasses. Hence, the clams and their microbial communities adapted successfully to a low-energy regime and may represent widespread chemosynthetic communities in the Japan Trench. In this regard, they contributed to the restricted deep-sea trench biodiversity as well as to the organic carbon availability, also for non-seep organisms, in such oligotrophic benthic environment of the dark deep ocean. © 2014 The

  19. Prevention

    DEFF Research Database (Denmark)

    Halken, S; Høst, A

    2001-01-01

    , breastfeeding should be encouraged for 4-6 months. In high-risk infants a documented extensively hydrolysed formula is recommended if exclusive breastfeeding is not possible for the first 4 months of life. There is no evidence for preventive dietary intervention neither during pregnancy nor lactation...... populations. These theories remain to be documented in proper, controlled and prospective studies. Breastfeeding and the late introduction of solid foods (>4 months) is associated with a reduced risk of food allergy, atopic dermatitis, and recurrent wheezing and asthma in early childhood. In all infants....... Preventive dietary restrictions after the age of 4-6 months are not scientifically documented....

  20. A study on the etiological agent and clinico-mycological correlation of fingernail onychomycosis in eastern India

    Directory of Open Access Journals (Sweden)

    Das Nilay

    2008-01-01

    Full Text Available Background: Onychomycosis manifests itself in various forms, notably onychodystrophy, onycholysis, subungual hyperkeratosis, or nail-plate discoloration. Not necessarily nail changes mentioned here should always be of fungal origin. Objective: The present study is planned to get an idea about etiological agent and clinical correlation in fingernail onychomycosis. Materials and Methods: Nail-clipping and subungual debris of patients with above mentioned nail changes were subjected to KOH preparation. Culture was done on SDA and SDCCA media. Species identification was done by colony character, pigment production, LCB staining, and some special tests like germ tube test, etc. Results: Out of 85 cases, 44 cases showed the growth of fungus, amounting to 51.76% positivity. Among those 44 cases, the infective fungal agents were predominantly dermatophytes (50%, and the rest were due to yeasts (27.27% and moulds (22.72%. Among the different species, Trichophyton rubrum (29.54% accounted for the majority of dermatophytes; Candida albicans (11.78% was the predominant yeast; and Aspergillus niger (18.18% the commonest mold. No significant association could be established between the different fungal species and various clinical manifestations. Positive results were found more with fungal culture (95.45% than KOH preparation (63.64%. Conclusion: The results show that nail changes are not always a reliable marker for predicting the causative organism, and relying only on the clinical manifestation (i.e., pattern of nail changes in the diagnosis of onychomycosis is often misleading. The present study highlights the need for microbiological confirmation in case of onychomycosis.

  1. Infection by gymnophallid metacercariae enhances predation mortality of SW Atlantic stout razor clam Tagelus plebeius

    Science.gov (United States)

    Addino, Mariana; Lomovasky, Betina J.; Cremonte, Florencia; Iribarne, Oscar

    2010-02-01

    Parasite life cycles are frequently completed in different hosts, thus the parasites have its life cycle overlapped to natural trophic webs. The family Gymnophallidae (Class: Trematoda; Subclass: Digenea) includes digenetic parasites whose larval stages occur on bivalves and may affect bivalve predation by the final host of these parasites. In this work we evaluated: (a) if individuals of the razor clam Tagelus plebeius with higher parasite intensity suffer higher predation by the oystercatcher Haematopus palliatus and, (b) if there is any effect of parasite intensity on burrowing and escape behaviours of these razor clams which may enhance exposure to predators. Field experiments (oystercatcher exclusion vs. open access) showed that clams with higher parasite intensity support higher predation by oystercatchers, which suggests a higher consumption of more parasitized clams and thus, a more successful reproduction of parasites linked to the intensity of infection. However, clam burrowing and escape behaviours did not show differences related to different parasite intensity, suggesting that the commonly believed mechanisms are not responsible in this case.

  2. Immune- and Pollution-mediated DNA Damage in Two Wild Mya arenaria Clam Populations

    Directory of Open Access Journals (Sweden)

    François Gagné

    2009-01-01

    Full Text Available In aquatic environments, genotoxicity results from the effects of pollution combined with the inflammatory response triggered by the immune system. Indeed, the production of nitrosylated DNA and proteins are though to arise from the production of peroxinitrite during phagocytosis and inflammation. The purpose of this study was to examine new DNA biomarkers that differentiate between immune- and pollution-mediated genotoxicity in wild clam populations. Intertidal clam populations were sampled and analyzed for gonadal DNA strand breaks, DNA nitrosylation and xanthine oxidoreductase (XOR activity (purine salvage pathway. The clam weight-to-shell-length ratio, the gonado-somatic index (GSI, age status, lipid peroxidation, xenobiotic conjugation activity (glutathione S-transferase (GST and phagocytic activity were examined to shed light on their relationships with the observed genotoxic endpoints. XOR activity and DNA strand breaks were generally elevated at polluted sites and correlated significantly with clam weight-to-shell-length ratios and DNA nitrosylation. DNA nitrosylation was also higher at some sites and correlated significantly with phagocytic activity and with DNA strand breaks. This study showed that DNA strand breaks were associated with both immune- and pollution-mediated effects. This suggests that there is a loss of DNA repair capacity due to the combined effects of aging, pollution and immune response in wild clam populations that are impacted by anthropogenic activity.

  3. Quantitative modeling for risk assessment of Vibrio parahaemolyticus in bloody clams in southern Thailand.

    Science.gov (United States)

    Yamamoto, Akio; Iwahori, Jun'ichiro; Vuddhakul, Varaporn; Charernjiratragul, Wilawan; Vose, David; Osaka, Ken; Shigematsu, Mika; Toyofuku, Hajime; Yamamoto, Shigeki; Nishibuchi, Mitsuaki; Kasuga, Fumiko

    2008-05-10

    A risk assessment of Vibrio parahaemolyticus in bloody clams (Anadara granosa) consumed in southern Thailand was conducted. This study estimated the prevalence and concentration of pathogenic V. parahaemolyticus in bloody clams at harvest and retail stages; and during this process, methods to detect the total and pathogenic V. parahaemolyticus were investigated. Consumption of bloody clams and cooking efficiency were studied using interviews and on-site observation of consumers. A beta-Poisson dose-response model was used to estimate probability of illness applying estimation methods for the most likely parameter values presented by USFDA. Microbial and behavioral data were analyzed by developing a stochastic model and the simulation gave a mean number of times a person would get ill with V. parahaemolyticus by consuming bloody clams at 5.6 x 10(-4)/person/year. Sensitivity analysis demonstrated the fraction of people who did not boil the clams properly was the primary factor in increasing risk. This study serves as an example of how a microbiological risk assessment with limited data collection and international cooperation leads to valuable local insight.

  4. Impediment to Symbiosis Establishment between Giant Clams and Symbiodinium Algae Due to Sterilization of Seawater

    Science.gov (United States)

    Kurihara, Takeo; Yamada, Hideaki; Inoue, Ken; Iwai, Kenji; Hatta, Masayuki

    2013-01-01

    To survive the juvenile stage, giant clam juveniles need to establish a symbiotic relationship with the microalgae Symbiodinium occurring in the environment. The percentage of giant clam juveniles succeeding in symbiosis establishment (“symbiosis rate”) is often low, which is problematic for seed producers. We investigated how and why symbiosis rates vary, depending on whether giant clam seeds are continuously reared in UV treated or non treated seawater. Results repeatedly demonstrated that symbiosis rates were lower for UV treated seawater than for non treated seawater. Symbiosis rates were also lower for autoclaved seawater and 0.2-µm filtered seawater than for non treated seawater. The decreased symbiosis rates in various sterilized seawater suggest the possibility that some factors helping symbiosis establishment in natural seawater are weakened owing to sterilization. The possible factors include vitality of giant clam seeds, since additional experiments revealed that survival rates of seeds reared alone without Symbiodinium were lower in sterilized seawater than in non treated seawater. In conclusion, UV treatment of seawater was found to lead to decreased symbiosis rates, which is due possibly to some adverse effects common to the various sterilization techniques and relates to the vitality of the giant clam seeds. PMID:23613802

  5. Gene transcription and biomarker responses in the clam Ruditapes philippinarum after exposure to ibuprofen

    International Nuclear Information System (INIS)

    Milan, Massimo; Pauletto, Marianna; Patarnello, Tomaso; Bargelloni, Luca; Marin, Maria Gabriella; Matozzo, Valerio

    2013-01-01

    Pharmaceuticals are a class of emerging environmental contaminants that continuously enter aquatic environments. Presently, little information is available about the effects of these substances on non-target organisms, such as bivalves. We investigated the effects of ibuprofen (IBU) on the clam Ruditapes philippinarum. Clams were exposed for 1, 3, 5 and 7 days to 0, 100 and 1000 μg IBU/L, and established biomarker responses (haemolymph lysozyme, gill acetylcholinesterase and digestive gland superoxide dismutase activities) as well as digestive gland transcriptome were evaluated. A two-way ANOVA revealed significant effects of both “IBU concentration” and “exposure duration” on biomarker responses. Overall, the enzyme activities were generally lower in IBU-exposed clams than in controls. Although limited knowledge of the mollusc transcriptome makes it difficult to interpret the effects of IBU on clams, the gene transcription analysis using DNA microarrays enabled the identification of the putative molecular mode of action of the IBU. The functional analysis of differentially transcribed genes suggests that IBU can interfere with various signalling pathways in clams, such as arachidonic acid metabolism, apoptosis, peroxisomal proliferator-activated receptors, and nuclear factor-kappa B. In addition, several genes involved in the metabolism of xenobiotics (e.g., glutathione S-transferase, sulfotransferase, cytochrome P450) were also found to be significantly affected by IBU exposure. In summary, the integrated approach of gene transcription analysis and biomarker responses facilitated the elucidation of the putative mechanisms of action of IBU in non-target species.

  6. Comparative genomics of vesicomyid clam (Bivalvia: Mollusca chemosynthetic symbionts

    Directory of Open Access Journals (Sweden)

    Girguis Peter R

    2008-12-01

    Full Text Available Abstract Background The Vesicomyidae (Bivalvia: Mollusca are a family of clams that form symbioses with chemosynthetic gamma-proteobacteria. They exist in environments such as hydrothermal vents and cold seeps and have a reduced gut and feeding groove, indicating a large dependence on their endosymbionts for nutrition. Recently, two vesicomyid symbiont genomes were sequenced, illuminating the possible nutritional contributions of the symbiont to the host and making genome-wide evolutionary analyses possible. Results To examine the genomic evolution of the vesicomyid symbionts, a comparative genomics framework, including the existing genomic data combined with heterologous microarray hybridization results, was used to analyze conserved gene content in four vesicomyid symbiont genomes. These four symbionts were chosen to include a broad phylogenetic sampling of the vesicomyid symbionts and represent distinct chemosynthetic environments: cold seeps and hydrothermal vents. Conclusion The results of this comparative genomics analysis emphasize the importance of the symbionts' chemoautotrophic metabolism within their hosts. The fact that these symbionts appear to be metabolically capable autotrophs underscores the extent to which the host depends on them for nutrition and reveals the key to invertebrate colonization of these challenging environments.

  7. Associated macrozoobenthos with the invasive Asian clam Corbicula fluminea

    Science.gov (United States)

    Ilarri, Martina I.; Freitas, Fabiana; Costa-Dias, Sérgia; Antunes, Carlos; Guilhermino, Lúcia; Sousa, Ronaldo

    2012-08-01

    The Asian clam Corbicula fluminea is one of the most invasive species in brackish and freshwater ecosystems. In the Minho estuary (NW of the Iberian Peninsula) this invasive species can reach densities up to 4000 ind m- 2, occurring over large areas. C. fluminea can significantly alter the physical structure of the benthic environment, and the structure and functioning of this estuarine community. In this context, this work aimed to evaluate the correlation of different densities of C. fluminea on the macrozoobenthos across five sites in the Minho estuary during three distinct periods of 2009 (winter, spring and summer). The comparative analysis indicate that macrozoobenthic density, biomass and diversity positively respond to increasing density of C. fluminea, with abiotic conditions also playing an important role in the observed patterns, both in brackish and freshwater settings. Crustacea, Insecta and Gastropoda are the main faunal groups responding positively to C. fluminea increasing density. The mechanisms responsible for these positive trends still needs to be established although engineering activities and the increase in waste products may play essential roles. Nevertheless, despite such positive effects, earlier studies have showed that the density, biomass and spatial distribution of some species, especially native bivalves dramatically decreased after C. fluminea introduction.

  8. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). Softshell Clam.

    Science.gov (United States)

    1986-08-01

    pm in diameter. Mucus , secreted by the Adult softshell clams feed by mantle, gills, and visceral mass, filtering microscopic particles of collects...Busycon canaliculatum, and the determining post-settling survival of lobed moon snail Polynices duplicatus softshell clams, predation by fish (Andrews 1970...consequently the mantle and gills are increasingly greater concentrations constantly exposed to sediments and increase mucus secretions and decrease

  9. Long-Term Surveys Show Invasive Overbite Clams (Potamocorbula amurensis are Spatially Limited in Suisun Marsh, California

    Directory of Open Access Journals (Sweden)

    Jason Baumsteiger

    2017-07-01

    Full Text Available https://doi.org/10.15447/sfews.2017v15iss2art6The overbite clam (Potamocorbula amurensis is a major invasive species in the San Francisco Estuary, California, and has been implicated in the decline of pelagic productivity and native fish species. Little is known of its impact on Suisun Marsh, a large brackish tidal region of the estuary. We looked at the abundance and spatial distribution of clams in the marsh, including examining the influence of water quality, using long-term (1988–2015 otter trawl surveys. Temporal trends indicated that overbite clam abundance has been increasing, but adult clams were spatially restricted to a single large slough (Suisun. Clams were absent from most interior channels, limiting their overall effect on the marsh aquatic ecosystem. Abiotic variables, particularly salinity, proved important predictors of overbite clam abundance, although the variables examined alone could not explain overbite clam distributions. We propose that connectivity, detritus loads, and/or predation pressure may work in conjunction with abiotic variables to cause poor survival rates for recruits in interior marsh sites, keeping the distribution limited. Overall results are encouraging for restoration projects in brackish tidal marshes that need to deal with overbite clams.

  10. Clam bioaccumulation of Alkylphenols and Polyciclic aromatic hydrocarbons in the Venice lagoon under different pressures.

    Science.gov (United States)

    Ademollo, N; Patrolecco, L; Matozzo, V; Marin, M G; Valsecchi, S; Polesello, S

    2017-11-15

    Biota-Sediment Accumulation Factors (BSAFs) of nonylphenols (NPs) and polycyclic aromatic hydrocarbons (PAHs) in Ruditapes philippinarum from the Venice Lagoon (Italy) were determined with the aim to verify whether the routine biomonitoring studies are reliable in contaminated sites. Clams and sediments were collected in field campaigns (October 2003 to June 2004) in three sites of the Venice Lagoon. Results showed that Marghera and Campalto sediments were more contaminated by NPs and PAHs than Poveglia. Different trends were observed in the contamination of clams with the highest BSAFs found at Poveglia. BSAF trend appeared to be inversely related to the contaminant pressure on the sites. These results suggest that clam bioaccumulation is not always representative of the chemical pressure on aquatic biota. The direct correlation between sediment and biota concentrations in contaminated sites can be lost as a function of the site-specific conditions such as sediment toxicity and food availability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Responses of Manila clam growth and its food sources to global warming in a subarctic lagoon in Japan

    Science.gov (United States)

    Yoon, Seokjin; Abe, Hiroya; Kishi, Michio J.

    2013-12-01

    Akkeshi Lake is a subarctic shallow brackish lagoon located in Hokkaido, Japan. The Manila clam, Ruditapes philippinarum, is cultured in sandy sediments at the shallow, intertidal flat near the mouth of the lake. To quantitatively evaluate the effects of environmental factors such as water temperature and food availability on the growth of the Manila clam and to estimate the responses of Manila clam growth and food availability to global warming in Akkeshi Lake, we developed a numerical model by coupling a three-dimensional ecosystem model with a bioenergetics model for the growth of the Manila clam. We ran the model under two different conditions: the present condition and the global warming condition. For the global warming condition, water temperature was increased by 2 °C at the open boundary for the entire computational period. The growth of the Manila clam was limited by water temperature and food availability. The Manila clam grew up to 1.33 g dry weight ind.-1 at the lake mouth (station A) for 5 years, whereas it grew up to 1.00 g dry weight ind.-1 at the lake center (station B). The difference in the biomass of the Manila clam between two stations was due to the difference in food availability. Under the global warming condition, the water temperature limitation for the Manila clam was relaxed with a water temperature increase. The Manila clam grew up to 1.55 g dry weight ind.-1 at station A and 1.10 g dry weight ind.-1 at station B. While the growth of the Manila clam was improved in the lake under the global warming condition, its food sources, especially phytoplankton, decreased because of ingestion increases of grazers.

  12. Effect of coastal eutrophication on heavy metal bioaccumulation and oral bioavailability in the razor clam, Sinonovacula constricta

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Tengxiu [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Li, Shunxing, E-mail: lishunxing@mnnu.edu.cn [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology (China); Chen, Lihui [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Zheng, Fengying; Huang, Xu-Guang [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology (China)

    2014-10-15

    Graphical abstract: - Highlights: • Razor clams are often exposed to coastal eutrophication. • The bioaccumulation of Fe, Ni, V, and As was promoted by eutrophication. • Bionic gastrointestinal tract was used for metal oral bioavailability assessment. • Eutrophication decreased oral bioavailability of Fe and Pb but enhanced for V. • The daily maximum allowable intakes are controlled by eutrophication levels. - Abstract: As traditional seafoods, the razor clams are widely distributed from tropical to temperate areas. Coastal razor clams are often exposed to eutrophication. Heavy metal contamination is critical for seafood safety. However, how eutrophication affects bioaccumulation and oral bioavailability of heavy metals in the razor clams is unknown. After a four-month field experimental cultivation, heavy metals (Fe, Cu, Ni, V, As, and Pb) could be bioaccumulated by the razor clams (Sinonovacula constricta) through exposure to metals present in water and sediments or in the food chain, and then transferred to human via consumption of razor clams. Bionic gastrointestinal digestion and monolayer liposome extraction are used for metal oral bioavailability (OBA) assessment. The influence of eutrophication on OBA is decreased for Fe and Pb and increased for V. A significant positive linear correlation was observed between the bioaccumulation factors of Fe, Ni, V, and As in razor clams and the coastal eutrophication. These results may be due to the effect of eutrophication on metal species transformation in coastal seawater and subcellular distribution in razor clams. The maximum allowable daily intakes of razor clams are controlled by eutrophication status and the concentration of affinity-liposome As in razor clams.

  13. Effect of coastal eutrophication on heavy metal bioaccumulation and oral bioavailability in the razor clam, Sinonovacula constricta

    International Nuclear Information System (INIS)

    Tu, Tengxiu; Li, Shunxing; Chen, Lihui; Zheng, Fengying; Huang, Xu-Guang

    2014-01-01

    Graphical abstract: - Highlights: • Razor clams are often exposed to coastal eutrophication. • The bioaccumulation of Fe, Ni, V, and As was promoted by eutrophication. • Bionic gastrointestinal tract was used for metal oral bioavailability assessment. • Eutrophication decreased oral bioavailability of Fe and Pb but enhanced for V. • The daily maximum allowable intakes are controlled by eutrophication levels. - Abstract: As traditional seafoods, the razor clams are widely distributed from tropical to temperate areas. Coastal razor clams are often exposed to eutrophication. Heavy metal contamination is critical for seafood safety. However, how eutrophication affects bioaccumulation and oral bioavailability of heavy metals in the razor clams is unknown. After a four-month field experimental cultivation, heavy metals (Fe, Cu, Ni, V, As, and Pb) could be bioaccumulated by the razor clams (Sinonovacula constricta) through exposure to metals present in water and sediments or in the food chain, and then transferred to human via consumption of razor clams. Bionic gastrointestinal digestion and monolayer liposome extraction are used for metal oral bioavailability (OBA) assessment. The influence of eutrophication on OBA is decreased for Fe and Pb and increased for V. A significant positive linear correlation was observed between the bioaccumulation factors of Fe, Ni, V, and As in razor clams and the coastal eutrophication. These results may be due to the effect of eutrophication on metal species transformation in coastal seawater and subcellular distribution in razor clams. The maximum allowable daily intakes of razor clams are controlled by eutrophication status and the concentration of affinity-liposome As in razor clams

  14. Differences in Abundances of Total Vibrio spp., V. vulnificus, and V. parahaemolyticus in Clams and Oysters in North Carolina.

    Science.gov (United States)

    Froelich, B A; Phippen, B; Fowler, P; Noble, R T; Oliver, J D

    2017-01-15

    Filter feeding shellfish can concentrate pathogenic bacteria, including Vibrio vulnificus and Vibrio parahaemolyticus, as much as 100-fold from the overlying water. These shellfish, especially clams and oysters, are often consumed raw, providing a route of entry for concentrated doses of pathogenic bacteria into the human body. The numbers of foodborne infections with these microbes are increasing, and a better understanding of the conditions that might trigger elevated concentrations of these bacteria in seafood is needed. In addition, if bacterial concentrations in water are correlated with those in shellfish, then sampling regimens could be simplified, as water samples can be more rapidly and easily obtained. After sampling of oysters and clams, either simultaneously or separately, for over 2 years, it was concluded that while Vibrio concentrations in oysters and water were related, this was not the case for levels in clams and water. When clams and oysters were collected simultaneously from the same site, the clams were found to have lower Vibrio levels than the oysters. Furthermore, the environmental parameters that were correlated with levels of Vibrio spp. in oysters and water were found to be quite different from those that were correlated with levels of Vibrio spp. in clams. This study shows that clams are a potential source of infection in North Carolina, especially for V. parahaemolyticus These findings also highlight the need for clam-specific environmental research to develop accurate Vibrio abundance models and to broaden the ecological understanding of clam-Vibrio interactions. This is especially relevant as foodborne Vibrio infections from clams are being reported. Copyright © 2016 American Society for Microbiology.

  15. Diarrhetic shellfish poisoning toxin esters in Danish blue mussels and surf clams

    DEFF Research Database (Denmark)

    Jørgensen, Kevin; Scanlon, Sine Hedegaard; Jensen, L.B.

    2005-01-01

    . Samples of Danish surf clams ( Spisola spp.) and blue mussels ( Mytilus edulis) from 1999 - 2004 were analysed by liquid chromatography coupled with tandem mass spectrometry ( LC/ MS/ MS) for the presence of DSP toxin esters. The samples contained only okadaic acid and esters of okadaic acid. The level...... of total okadaic acid equivalents ranged from 224 to 2516 mu g kg (-1) in surf clams. The percentage of okadaic acid esters of the total okadaic acid equivalents ranged from 83 to 98%, mean 95%. The level of total okadaic acid equivalents ranged from 43 to 1631 mu g kg (-1) in blue mussels. The percentage...

  16. Improved recovery of repeat intoxicated drivers using fingernails and blood spots to monitor alcohol and other substance abuse.

    Science.gov (United States)

    Bean, Pamela; Brown, Guida; Hallinan, Patricia; Becerra, Sergio; Lewis, Doug

    2017-01-02

    This study reports the results of a pilot program in Kenosha County that used a combination of direct biomarkers extracted from blood spots and nails to monitor repeat intoxicated drivers for their use of alcohol and drugs with a detection window spanning from 3 weeks to several months. The objectives were to test whether the direct biomarkers phosphatidylethanol (PEth), ethylglucuronide (EtG), and 5 drug metabolites would (1) help assessors obtain a more objective evaluation of repeat offenders during the assessment interview, (2) allow for timely identification of relapses and improve classification of drivers into risk categories, and (3) predict recidivism by identifying offenders most likely to obtain a subsequent operating while intoxicated (OWI) offense within 4 years of enrollment in the program. All (N = 261) repeat offenders were tested using PEth obtained from blood spots and EtG obtained from fingernails; 159 participants were also tested for a 5 drugs of abuse nail panel. Drivers were tested immediately after the assessment interview (baseline) and at 3, 6, 9, and 12 months after baseline. Based on biomarker results and self-reports of abstinence, offenders were classified into different risk categories and required to follow specific testing timelines based on the program's decision tree. The baseline analysis shows that 60% of drivers tested positive for alcohol biomarkers (EtG, PEth, or both) at the assessment interview, with lower detection rates (0-11%) for the 5 drug metabolites. The comparison of biomarkers results to self-reports of abstinence identified 28% of all offenders as high risk and assigned them to more frequent testing and more intense monitoring. The longitudinal analysis shows that 56% (completers) of participants completed the program successfully and the remaining 44% (noncompliant) terminated prematurely. Two thirds (68%) of the completers were able to reduce or control their drinking and one third relapsed at least one time

  17. Uptake and release of paralytic shellfish toxins by the clam Ruditapes decussatus exposed to Gymnodinium catenatum and subsequent depuration.

    Science.gov (United States)

    Botelho, Maria João; Vale, Carlos; Grilo, Rita Velez; Ferreira, João Gomes

    2012-06-01

    A laboratory experiment was performed with the clam Ruditapes decussatus, fed with the toxic dinoflagellate Gymnodinium catenatum and the non-toxic algae Isochrysis galbana (14 days) and subsequently only with I. galbana (15 days). Individual paralytic shellfish toxins were determined by LC-FLD in G. catenatum cells, whole clam tissues, and particulate organic matter (POM) produced by clams. The toxins dcSTX and dcGTX2 + 3 in the algae were less abundant than C1 + 2 and B1, but were predominant in clams during both the exposure and depuration phases. The toxin dcNEO was only detected in clams during a short period, indicating conversion from other compounds. The toxin composition of the POM indicated the export of dcSTX as faeces or pseudo-faeces along the entire experiment (2.5-14 nmol mg(-1)), B1 was present in a short period of the exposure and C1 + 2 and dcGTX2 + 3 absent. A mass balance calculation indicated that approximately 95% of C1 + 2 and 85% of B1 supplied to the clams were converted into other toxins or lost in solution. Conversely, the net gain of 512, 61 and 31 nmol for dcSTX, dcGTX2 + 3 and dcNEO, respectively, suggests the conversion from other assimilated compounds by clams during exposure and depuration phases. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Species profiles: Life histories and environmental requirements of coastal fish and invertebrates (North Atlantic): Softshell clam. [Mya arenaria

    Energy Technology Data Exchange (ETDEWEB)

    Newell, C.R.; Hidu, H.

    1986-06-01

    The softshell clam, Mya arenaria, is a commercially and recreationally important invertebrate that inhabits the bottom sediments of subtidal and intertidal waters of moderate to high salinity. Its range is limited by water temperatures too low for reproduction in the north and by lethal warm temperatures in the south. Clams feed by siphoning seawater and removing food particles, especially phytoplankton, with their gills. Clams are therefore sensitive to factors affecting water quality, including suspended sediments, salinity, water temperature, oxygen, and waterborne pollutants. The clam life cycle consists of mass spawning and external fertilization, the development of pelagic larvae, settlement and metamorphosis into spat, and rapid juvenile growth to maturity. Clam recruitment and the migration of spat are dependent upon inshore currents. High morality of eggs, larvae, and spat is largely offset by high reproductive potential. As the clam grows, it finds refuge from most predators deep in the sediments, but it also loses its ability to burrow and is subject to suffocation by siltation. Sediment types, currents, and tidal heights all affect clam growth rates.

  19. Direct contribution of clams (Ruditapes philippinarum) to benthic fluxes, nitrification, denitrification and nitrous oxide emission in a farmed sediment

    Science.gov (United States)

    Welsh, David T.; Nizzoli, Daniele; Fano, Elisa A.; Viaroli, Pierluigi

    2015-03-01

    The influence of the manila clam (Ruditapes philippinarum) on N-cycle processes, and oxygen and nutrient fluxes in a farmed sediment was investigated using a multiple core incubation approach and parallel incubations of individual clams. Clam population/biomass density varied ∼8-fold between cores and all sediment-water column solute (O2. N2, N2O, NH4+, NOX and DIN) fluxes and benthic process (N-regeneration, nitrification and denitrification) rates were strongly and significantly correlated with clam density/biomass. Isolated clams exhibited high rates of respiration, N-excretion, nitrification and denitrification of 2050 ± 70, 395 ± 49, 201 ± 42 and 235 ± 40 nmol individual-1 h-1, respectively. The direct contribution of the clams and their associated microbiota to benthic processes was estimated by multiplying the per individual rates by the number of clams in each incubated core. The clams on average directly accounted for 64-133% of total rates of sediment oxygen demand, N-regeneration, nitrification and denitrification, indicating that they regulated processes primarily through their own metabolic activity and that of bacteria that colonise them. Clams and the farmed sediments were significant sources of the greenhouse gas N2O, but this was primarily due to their high nitrification and denitrification rates, rather than high specific N2O yields, as N2O emissions represented farmed sediments had a high denitrification efficiency of 67 ± 10%, but this ecosystem service came at the environmental cost of increased N-regeneration and N2O emission rates. The measured N2O emissions indicate that bivalve aquaculture may be a significant source of N2O. It is therefore recommended that N2O emissions should be included in the impact assessments of current and future bivalve-farming projects.

  20. Effect of mining activities on the clam fisheries and bottom fauna of Goa estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.; Ansari, Z.A.; Ingole, B.S.

    Comparison of two clam beds and associated benthic fauna, in Mandovi and Cumbarjua canal estuarine system of Goa, India, severely affected by massive inputs of mining rejects, revealed that, in less than 10 years (1972-73 to 1982-83), high biotic...

  1. Microstructures and Mechanical Properties of Laser Welding Joint of a CLAM Steel with Revised Chemical Compositions

    Science.gov (United States)

    Chen, Shuhai; Huang, Jihua; Lu, Qi; Zhao, Xingke

    2016-05-01

    To suppress the tendency to form delta ferrite in weld metal (WM) of China low activation martensitic (CLAM) steel joint, a CLAM steel with revised chemical compositions was designed. Laser welding of the CLAM steel was investigated. The microstructures of the WM and heat-affected zone were analyzed. The impact toughness of the WM was evaluated by a Charpy impact test method with three V notches. The influence of temper temperature on mechanical properties was analyzed. It was found that the delta ferrite was eliminated almost completely in laser WM of CLAM steel with revised chemical compositions which has lower tendency to form delta ferrite than original chemical compositions. The joint has higher tensile strength than the parent metal. With increasing the heat input, the impact toughness of the joint is approximatively equal with that of parent metal first and then decreases obviously. Temper treatment could effectively improve mechanical property of the joint. When the temper temperature exceeds 600 °C, the impact toughness of the joint is higher than that of the parent metal.

  2. CLAM - CoLlAborative eMbedded networks for submarine surveillance: An overview

    NARCIS (Netherlands)

    Meratnia, Nirvana; Havinga, Paul J.M.; Casari, Paolo; Petrioli, Chiara; Grythe, Knut; Husoy, Thor; Zorzi, Michele

    2011-01-01

    This paper provides an overview of the CLAM project, which aims at developing a collaborative embedded monitoring and control platform for submarine surveillance by combining cutting edge acoustic vector sensor technology and 1D, 2D, 3D sensor arrays, underwater wireless sensor networks protocol

  3. First molluscan antimicrobial peptide hydramacin in Manila clam: molecular characterization and expression analysis

    Directory of Open Access Journals (Sweden)

    Youngdeuk Lee

    2014-06-01

    Full Text Available Objective: To investigate molecular characterization and the immune responses of Manila clam hydramacin (Rp-hdmc. Methods: cDNA sequence of hydramacin was isolated from Manila clam transcriptome database. Molecular characterization of hydramacin cDNA was performed by BLAST and SWISS-MODEL bioinformatics programs. Tissue-specific expression and transcriptional regulation after Vibrio tapetis challenge was done by quantitative real time PCR. Results: Rp-hdmc has 291 bp open reading frame (ORF, encoding 97 amino acids with a mature hydramacin consisting of 77 amino acid residues. In un-challenged clam, Rp-hdmc was constitutively expressed in all tested tissues and the highest expression level was detected in gill. After pathogenic bacteria Vibrio tapetis challenge, Rp-hdmc mRNA was up-regulated in gill and hemocytes. Conclusions: We identified hydramacin cDNA (Rp-hdmc from mollusk Manila clam that shows the characteristic features of hydramacin sequence. It has eight cysteine residues with four disulfide linkages, three helices and two β-strands in secondary structure. Expression results after V. tapetis challenges suggest that Rp-hdmc is involved in immune response against pathogenic bacteria.

  4. Allometric relationships in the bioconcentration of heavy metals by the edible tropical clam Gafrarium tumidum

    International Nuclear Information System (INIS)

    Hedouin, L.; Metian, M.; Teyssie, J.-L.; Fowler, S.W.; Fichez, R.; Warnau, M.

    2006-01-01

    Although metal contamination is a problem of major concern in the lagoon of New Caledonia due to intense mining activities conducted on land, very little is known on the metal ecotoxicology of local marine organisms. The clam Gafrarium tumidum was investigated to assess its usefulness as a bioindicator species of metal contamination in this lagoon. More particularly, allometric relationships between metal accumulation and clam size were determined for five common metals in New Caledonian lagoon waters (Cd, Cr, Co, Zn and Ag) using a highly sensitive radiotracer technique. Experimental results showed that allometric relationships were dependent on the element and on the body compartment considered. As a rule, allometric relationships of metal concentration factor were more pronounced in shell than in soft parts. Significant relationships with clam size for Cd, Cr, Co and Zn followed inverse power functions. In contrast, the degree of Ag bioaccumulation was positively correlated with size. In view of the literature on Ag in bivalves, the latter observation suggests the occurrence of a specific detoxification mechanism (sequestration) that would be more efficient in old individuals. Overall, the experimental results indicate that the use of G. tumidum as a bioindicator in monitoring programmes requires selecting individuals of a specific size range in order to obtain comparable information about ambient metal levels. Since the size effect is greatest among smaller individuals, it is recommended to select clams with a shell width greater than 35 mm

  5. Gametogenic development and spawning of the mud clam, Polymesoda erosa (Solander, 1876) at Chorao Island, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Clemente, S.; Ingole, B.S.

    to 4.7 in March, with low values during the spawning period. The clams attained their best condition in quality of flesh weight during March-May. The data presented here should provide valuable information on the timing of spawning events for P. erosa...

  6. The clam (Chamelea gallina: evaluation of the effects of solids suspended in seawater on bivalve molluscs

    Directory of Open Access Journals (Sweden)

    Salvatora Angela Angioni

    2010-03-01

    Full Text Available The study was designed to evaluate the effects of solids in suspension in seawater on clams (Chamelea gallina. The aim was to investigate the possible correlation between the widespread deaths of clams in the coastal waters of the central and northern Adriatic in the last five years and increased concentrations of solids in suspension. The research involved conducting 96-hour tests on clams farmed in aquariums containing filtered seawater. The tests were preceded by a 7-day adaptation stage to allow the molluscs to acclimatise. During this period, the clams were fed on unicellular seaweed (Dunaliella tertiolecta. The molluscs were exposed to particles of solids in suspension consisting of pools of silica gel (SiO2 granules of various sizes, similar to those constituting silt, whose presence and suspension in the sea considerably increase after heavy rain and heavy seas. The study established that the number of deaths caused by solids suspended in seawater at the concentrations used in the tests was not statistically significant.

  7. The wedge clam Donax serra, popularly known as the white sand ...

    African Journals Online (AJOL)

    spamer

    Another choice is which market to target for selling the clams. The choice of market destinations is dictated by the need to cover local coastal and inland options as well as an export one. Whereas more distant markets are more costly to sell to, they often yield higher returns. To gain information on the merits of these choices,.

  8. Cadmium sulfide quantum dots induce oxidative stress and behavioral impairments in the marine clam Scrobicularia plana.

    Science.gov (United States)

    Buffet, Pierre-Emmanuel; Zalouk-Vergnoux, Aurore; Poirier, Laurence; Lopes, Christelle; Risso-de-Faverney, Christine; Guibbolini, Marielle; Gilliland, Douglas; Perrein-Ettajani, Hanane; Valsami-Jones, Eugenia; Mouneyrac, Catherine

    2015-07-01

    Cadmium sulfide (CdS) quantum dots have a number of current applications in electronics and solar cells and significant future potential in medicine. The aim of the present study was to examine the toxic effects of CdS quantum dots on the marine clam Scrobicularia plana exposed for 14 d to these nanomaterials (10 µg Cd L(-1) ) in natural seawater and to compare them with soluble Cd. Measurement of labile Cd released from CdS quantum dots showed that 52% of CdS quantum dots remained in the nanoparticulate form. Clams accumulated the same levels of Cd regardless of the form in which it was delivered (soluble Cd vs CdS quantum dots). However, significant changes in biochemical responses were observed in clams exposed to CdS quantum dots compared with soluble Cd. Increased activities of catalase and glutathione-S-transferase were significantly higher in clams exposed in seawater to Cd as the nanoparticulate versus the soluble form, suggesting a specific nano effect. The behavior of S. plana in sediment showed impairments of foot movements only in the case of exposure to CdS quantum dots. The results show that oxidative stress and behavior biomarkers are sensitive predictors of CdS quantum dots toxicity in S. plana. Such responses, appearing well before changes might occur at the population level, demonstrate the usefulness of this model species and type of biomarker in the assessment of nanoparticle contamination in estuarine ecosystems. © 2015 SETAC.

  9. Soft shell clams Mya arenaria with disseminated neoplasia demonstrate reverse transcriptase activity

    Science.gov (United States)

    House, M.L.; Kim, C.H.; Reno, P.W.

    1998-01-01

    Disseminated neoplasia (DN), a proliferative cell disorder of the circulatory system of bivalves, was first reported in oysters in 1969. Since that time, the disease has been determined to be transmissible through water-borne exposure, but the etiological agent has not been unequivocally identified. In order to determine if a viral agent, possibly a retrovirus, could be the causative agent of DN, transmission experiments were performed, using both a cell-free filtrate and a sucrose gradient-purified preparation of a cell-free filtrate of DN positive materials. Additionally, a PCR-enhanced reverse transcriptase assay was used to determine if reverse transcriptase was present in tissues or hemolymph from DN positive soft shell clams Mya arenaria. DN was transmitted to healthy clams by injection with whole DN cells, but not with cell-free flitrates prepared from either tissues from DN positive clams, or DN cells. The cell-free preparations from DN-positive tissues and hemolymph having high levels of DN cells in circulation exhibited positive reactions in the PCR-enhanced reverse transcriptase assay. Cell-free preparations of hemolymph from clams having low levels of DN (reverse transcriptase assay.

  10. Purification and Characterization of Hemagglutinating Proteins from Poker-Chip Venus (Meretrix lusoria) and Corbicula Clam (Corbicula fluminea)

    OpenAIRE

    Cheng, Chin-Fu; Hung, Shao-Wen; Chang, Yung-Chung; Chen, Ming-Hui; Chang, Chen-Hsuan; Tsou, Li-Tse; Tu, Ching-Yu; Lin, Yu-Hsing; Liu, Pan-Chen; Lin, Shiun-Long; Wang, Way-Shyan

    2012-01-01

    Hemagglutinating proteins (HAPs) were purified from Poker-chip Venus (Meretrix lusoria) and Corbicula clam (Corbicula fluminea) using gel-filtration chromatography on a Sephacryl S-300 column. The molecular weights of the HAPs obtained from Poker-chip Venus and Corbicula clam were 358 kDa and 380 kDa, respectively. Purified HAP from Poker-chip Venus yielded two subunits with molecular weights of 26 kDa and 29 kDa. However, only one HAP subunit was purified from Corbicula clam, and its molecul...

  11. Glycation in human fingernail clippings using ATR-FTIR spectrometry, a new marker for the diagnosis and monitoring of diabetes mellitus.

    Science.gov (United States)

    Coopman, Renaat; Van de Vyver, Thijs; Kishabongo, Antoine Sadiki; Katchunga, Philippe; Van Aken, Elisabeth H; Cikomola, Justin; Monteyne, Tinne; Speeckaert, Marijn M; Delanghe, Joris R

    2017-01-01

    Although HbA1c is a good diagnostic tool for diabetes, the precarity of the health system and the costs limit the use of this biomarker in developing countries. Fingernail clippings contain ±85% of keratins, which are prone to glycation. Nail keratin glycation may reflect the average glycemia over the last months. We explored if attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) can be used as a non-invasive tool for assessing glycation in diabetes. Using ATR-FTIR spectroscopy, glycation and deglycation experiments with fructosamine 3-kinase allowed to identify the spectrum that corresponds with keratin glycation in fingernail clippings. Clippings of 105 healthy subjects and 127 diabetics were subjected to the standardized ATR-FTIR spectroscopy method. In vitro glycation resulted in an increased absorption at 1047cm -1 . Following enzymatic deglycation, this peak diminished significantly, proving that the AUC between 970 and 1140cm -1 corresponded with glycated proteins. Within-run CV of the assay was 3%. Storage of nail clippings at 37°C for 2weeks did not significantly change results. In diabetics, glycated nail protein concentrations (median: 1.51μmol/g protein, IQR: 1.37-1.85μmol/g protein) were significantly higher than in the controls (median: 1.19μmol/g protein, IQR: 1.09-1.26μmol/g protein) (p<0.0001). ROC analysis yielded an AUC of 0.92 at a cut-off point of 1.28μmol/g nail (specificity: 82%; sensitivity: 90%). No correlation was observed between the glycated nail protein concentrations and HbA1c. Protein glycation analysis in fingernails with ATR-FTIR spectroscopy could be an alternative affordable technique for diagnosing and monitoring diabetes. As the test does not consume reagents, and the preanalytical phase is extremely robust, the test could be particularly useful in developing countries. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  12. Enhancement of dietary effect of Nannochloropsis sp. on juvenile Ruditapes philippinarum clams by alginate hydrolysates

    Directory of Open Access Journals (Sweden)

    Yasuhiro Yamasaki

    2018-02-01

    Full Text Available The eustigmatophyte Nannochloropsis sp. can be produced on a large scale at low cost. However, its dietary usefulness for juvenile bivalves is less than that of other algae. Recently, we reported that growth of juveniles of the clam Ruditapes philippinarum was dramatically promoted by supplementing a diet of the diatom Chaetoceros neogracile with alginate hydrolysates (AHs at the concentration of 4 mg L−1. In this study, we examined the effect of AHs on Nannochloropsis sp. as a clam diet. Ten-day rearing experiments in 500-mL beakers showed that AHs have a beneficial effect on clam culture regardless of water temperature. Shell growth in clams given AHs at the concentration of 4 mg L−1 along with Nannochloropsis sp. at the concentration of 20 × 104 cells mL−1 was higher than in any other test groups at 15 or 25 °C. In 20-day rearing experiments in 30-L tanks, the average shell length in the groups given AHs at the concentration of 4 mg L−1 along with Nannochloropsis sp. at the concentration of 30 × 104 cells mL−1 was significantly greater than that in the groups given C. neogracile and Nannochloropsis sp. alone (P ≪ 0.05. Furthermore, the total weight of clams given AHs at the concentration of 4 mg L−1 along with Nannochloropsis sp. at the concentration of 30 × 104 cells mL−1 was greater than that in the group given only Nannochloropsis sp. (P ≪ 0.05. Hence, the enhanced dietary effect of a combination of Nannochloropsis sp. and AHs will help to shorten the rearing time of R. philippinarum and to provide a stable supply of algal diet.

  13. Preliminary Study on Hot Isostatic Pressing Diffusion Bonding for CLAM Steel

    International Nuclear Information System (INIS)

    Chunjing Li; Qunying Huang; Yican Wu

    2006-01-01

    China Low Activation Martensitic (CLAM) steel is being developed in ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences) since three years ago. CLAM is selected as the major candidate structure materials for the FDS series design of fusion reactors and for China liquid metal LiPb Test Blanket Module (TBM) for ITER i.e. DFLL-TBM, which are being carried out in ASIPP. Since the hot isostatic pressing (HIP) bonding technique is one of the main candidate bonding techniques for manufacturing of the first wall of a fusion reactor, research of the HIP technique on CLAM/CLAM is greatly needed. Preliminary HIP diffusion bonding experiments on CLAM steel have been performed. A few machining approaches such as dry-milling, turnery and grounding etc. were used to prepare the sample surfaces and then they were degreased with a mixture of alcohol, ether and acetone in an ultrasonic bath. The samples were joined by HIP diffusion bonding with the compression pressure of 150 MPa and the holding time of 2 ∼ 3 hours under different temperatures between 950 deg. and 1100 deg.. Different seal techniques of the capsules were studied as well. Then appropriate post heat treatment was done. Tests on mechanical properties of the joints such as tensile strength and impact toughness have been performed. The preliminary results show that the tensile properties are roughly the same as those of the base material. The absorbed energy of the joints at present is a little low and further research is needed to increase it. Microstructure of the joints was studied by optical microscope, SEM and TEM. Compositions of the defects on the joining line were analyzed by EDS. Through analysis of the results, optimized parameters for HIP are given. (author)

  14. Gene transcription and biomarker responses in the clam Ruditapes philippinarum after exposure to ibuprofen

    Energy Technology Data Exchange (ETDEWEB)

    Milan, Massimo; Pauletto, Marianna; Patarnello, Tomaso; Bargelloni, Luca [Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell' Universita 16, Legnaro (Padova) (Italy); Marin, Maria Gabriella [Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131 Padova (Italy); Matozzo, Valerio, E-mail: matozzo@bio.unipd.it [Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131 Padova (Italy)

    2013-01-15

    Pharmaceuticals are a class of emerging environmental contaminants that continuously enter aquatic environments. Presently, little information is available about the effects of these substances on non-target organisms, such as bivalves. We investigated the effects of ibuprofen (IBU) on the clam Ruditapes philippinarum. Clams were exposed for 1, 3, 5 and 7 days to 0, 100 and 1000 {mu}g IBU/L, and established biomarker responses (haemolymph lysozyme, gill acetylcholinesterase and digestive gland superoxide dismutase activities) as well as digestive gland transcriptome were evaluated. A two-way ANOVA revealed significant effects of both 'IBU concentration' and 'exposure duration' on biomarker responses. Overall, the enzyme activities were generally lower in IBU-exposed clams than in controls. Although limited knowledge of the mollusc transcriptome makes it difficult to interpret the effects of IBU on clams, the gene transcription analysis using DNA microarrays enabled the identification of the putative molecular mode of action of the IBU. The functional analysis of differentially transcribed genes suggests that IBU can interfere with various signalling pathways in clams, such as arachidonic acid metabolism, apoptosis, peroxisomal proliferator-activated receptors, and nuclear factor-kappa B. In addition, several genes involved in the metabolism of xenobiotics (e.g., glutathione S-transferase, sulfotransferase, cytochrome P450) were also found to be significantly affected by IBU exposure. In summary, the integrated approach of gene transcription analysis and biomarker responses facilitated the elucidation of the putative mechanisms of action of IBU in non-target species.

  15. New polymorphic microsatellite markers derived from hemocyte cDNA library of Manila clam Ruditapes philippinarum challenged by the protozoan parasite Perkinsus olseni

    Science.gov (United States)

    Kang, Hyun-Sil; Hong, Hyun-Ki; Park, Kyung-Il; Cho, Moonjae; Youn, Seok-Hyun; Choi, Kwang-Sik

    2017-03-01

    Manila clam Ruditapes philippinarum is one of the most important benthic animals in the coastal north Pacific region, where clam populations have been mixed genetically through trade and aquaculture activities. Accordingly, identification of the genetically different clam populations has become one of the most important issues to manage interbreeding of the local and introduced clam populations. To identify genetically different populations of clam populations, we developed 11 expressed sequence tag (EST)-microsatellite loci (i.e., simple sequence repeat, SSR) from 1,128 clam hemocyte cDNA clones challenged by the protozoan parasite Perkinsus olseni. Genotype analysis using the markers developed in this study demonstrated that clams from a tidal flat on the west coast contained 6 to 19 alleles per locus, and a population from Jeju Island had 4 to 20 alleles per locus. The expected heterozygosity of the 2 clam populations ranged from 0.472 to 0.919 for clams from the west coast, and 0.494 to 0.919 for clams from Jeju Island, respectively. Among the 11 loci discovered in this study, 7 loci significantly deviated from the Hardy-Weinberg equilibrium after Bonferroni correction. The 5 loci developed in this study also successfully amplified the SSRs of R. variegatus, a clam species taxonomically very close to R. philippinarum, from Hong Kong and Jeju Island. We believe that the 11 novel polymorphic SSR developed in this study can be utilized successfully in Manila clam genetic diversity analysis, as well as in genetic discrimination of different clam populations.

  16. Bioaccumulation of hydrocarbons derived from terrestrial and anthropogenic sources in the Asian clam, Potamocorbula amurensis, in San Francisco Bay estuary

    Science.gov (United States)

    Pereira, Wilfred E.; Hostettler, Frances D.; Rapp, John B.

    1992-01-01

    An assessment was made in Suisun Bay, California, of the distributions of hydrocarbons in estuarine bed and suspended sediments and in the recently introduced asian clam, Potamocorbula amurensis. Sediments and clams were contaminated with hydrocarbons derived from petrogenic and pyrogenic sources. Distributions of alkanes and of hopane and sterane biomarkers in sediments and clams were similar, indicating that petroleum hydrocarbons associated with sediments are bioavailable to Potamocorbula amurensis. Polycyclic aromatic hydrocarbons in the sediments and clams were derived mainly from combustion sources. Potamocorbula amurensis is therefore a useful bioindicator of hydrocarbon contamination, and may be used as a biomonitor of hydrocarbon pollution in San Francisco Bay.

  17. Cohort life tables for a population of the soft-shell clam, Mya arenaria L., in the White Sea

    Science.gov (United States)

    Gerasimova, Alexandra V.; Maximovich, Nikolay V.; Filippova, Nadezhda A.

    2015-06-01

    The Mya arenaria generation in the White Sea was observed for almost the whole life cycle (around 25 years). Using the data on this generation dynamics, the cohort life table was built. The main purpose of the research is analysis of age-specific mortality in this soft-shell clam population. The mortality rate was found to change more than tenfold throughout the study period. No regular changes in its value were observed. Periods of low mortality alternated with periods of much higher mortality. Several reasons for the increase in M. arenaria mortality rate during its life cycle are proposed: (a) living in the surface sediment layer at early stages of life cycle (unstable environment, high mortality of non-viable clams, predator impact); (b) intense intraspecific relationships in dense aggregations of young clams; (c) increased intraspecific competition during periods of the rapid individual growth; (d) ageing (clam mortality increases with older age—achievement of an average and a maximum lifespan).

  18. Association between sex inequality in animal protein intake and economic development in the Papua New Guinea highlands: The carbon and nitrogen isotopic composition of scalp hair and fingernail.

    Science.gov (United States)

    Umezaki, Masahiro; Naito, Yuichi I; Tsutaya, Takumi; Baba, Jun; Tadokoro, Kiyoshi; Odani, Shingo; Morita, Ayako; Natsuhara, Kazumi; Phuanukoonnon, Suparat; Vengiau, Gwendalyn; Siba, Peter M; Yoneda, Minoru

    2016-01-01

    People in the Papua New Guinea Highlands consume sweet potatoes as their dietary staple; consumption of animal protein is limited. In such societies with marginal protein intake, the intra-household allocation of animal protein in terms of sex or age is of importance. The objective of this study was to investigate how the allocation pattern of protein-rich foods by sex and age is associated with economic development in the Papua New Guinea Highlands. The carbon and nitrogen isotopic compositions of fingernails, collected in 1995 in two areas (Tari and Port Moresby [the national capital where Tari migrants resided]), and of scalp hair, collected in 2007, 2012, and 2013 in three areas of different degree of economic development (Levani, Tari, and Goroka) were analyzed. Analysis of fingernail samples showed that δ(15)N was lower in rural communities than in the urban migrant community, while a sex difference in δ(15)N (higher in males than in females) was found in the former but not in the latter community. Age was not associated with either δ(15)N or δ(13)C values. The analysis of scalp hair samples showed that δ(15)N values were lowest in Levani, the least developed area. Furthermore, there were statistically significant sex differences in δ(15)N values in Levani but not in Tari and Goroka. Age was not associated with either δ(15)N or δ(13)C values. The sex inequality in animal protein consumption seems to have decreased as the communities in the Papua New Guinea Highlands have experienced economic development. © 2015 Wiley Periodicals, Inc.

  19. Size-related and seasonal diet of the manila clam (Ruditapes philippinarum), as determined using dual stable isotopes

    Science.gov (United States)

    Suh, Yeon Jee; Shin, Kyung-Hoon

    2013-12-01

    Stable isotope ratios of lab-cultured Manila clams (Ruditapes philippinarum) and those from natural tidal flats of Seonjae Island in Korea were investigated in terms of their dietary uptake patterns in relation to body size and season. The smallest size group of wild Manila clams revealed significantly depleted δ15N based on the results of a one-way ANOVA. There was significant seasonal change in the proportional contribution of food sources, especially in winter, from benthic particulate organic matter (BPOM) to pelagic particulate organic matter (POM). Laboratory-cultured Manila clams showed growth rates of 6.02-37.75 mm/yr, and smaller-sized clams did not fully utilise the microalgal diets that were provided constantly. Instead, they derived most of their energy from detritus or dead microalgae that had settled on the bottom. Bigger clams, however, exhibited well-balanced source contributions, converting the microalgal diets into biomass. This demonstrates intra-specific differences in the growth rates and preferred diet uptakes of Manila clams, even under similar environmental conditions.

  20. Long-Term Acclimation to Different Thermal Regimes Affects Molecular Responses to Heat Stress in a Freshwater Clam Corbicula Fluminea

    Science.gov (United States)

    Falfushynska, Halina I.; Phan, Tuan; Sokolova, Inna M.

    2016-12-01

    Global climate change (GCC) can negatively affect freshwater ecosystems. However, the degree to which freshwater populations can acclimate to long-term warming and the underlying molecular mechanisms are not yet fully understood. We used the cooling water discharge (CWD) area of a power plant as a model for long-term warming. Survival and molecular stress responses (expression of molecular chaperones, antioxidants, bioenergetic and protein synthesis biomarkers) to experimental warming (20-41 °C, +1.5 °C per day) were assessed in invasive clams Corbicula fluminea from two pristine populations and a CWD population. CWD clams had considerably higher (by ~8-12 °C) lethal temperature thresholds than clams from the pristine areas. High thermal tolerance of CWD clams was associated with overexpression of heat shock proteins HSP70, HSP90 and HSP60 and activation of protein synthesis at 38 °C. Heat shock response was prioritized over the oxidative stress response resulting in accumulation of oxidative lesions and ubiquitinated proteins during heat stress in CWD clams. Future studies should determine whether the increase in thermal tolerance in CWD clams are due to genetic adaptation and/or phenotypic plasticity. Overall, our findings indicate that C. fluminea has potential to survive and increase its invasive range during warming such as expected during GCC.

  1. Effects of clam size, food type, sediment characteristic, and seawater carbonate chemistry on grazing capacity of Venus clam Cyclina sinensis (Gmelin, 1791)

    Science.gov (United States)

    Lin, Tingting; Zhou, Kai; Liu, Xin; Lai, Qifang; Zhang, Dong; Shi, Liyan

    2017-09-01

    Aquaculture in saline-alkaline water has a major problem: microalgal blooming causes the pH of water to increase dramatically, thereby causing damage to the reared organisms. To solve this problem, we set out to find a candidate filter-feeding bivalve species suitable for saline-alkaline water to graze on microalgae and to control the pH. In the current study, we investigated the effect of carbonate alkalinity (CA, 2.5, 10.0, and 20.0 meq/L) and pH (8.0, 8.5, and 9.0) on the grazing capacity (GC) of the clam Cyclina sinensis. Additionally, the effect of clam size (small, medium, and large) and microalgae species ( Nannochloropsis oculata, Chaetoceros müelleri, and Isochrysis galbana), and the effect of bottom sediment characteristic (mud, sandy mud, and muddy sand) and thickness (3 and 6 cm) were analyzed as well. The results show that the GC on I. galbana was the highest and small size had the maximum GC/ W ( W: wet weight including body and shells). No significant differences were observed between sediment type and thickness. Regarding CA and pH, a significant decrease in GC by the pH or by their interaction was found. The GC of C. sinensis was not greatly reduced in the treatments of pH≤8.5 and CA≤20.0, and also not affected by bottom sediment type, indicating that this clam is capable to manage microalgal concentrations and might be a candidate species for pH reduction in saline-alkaline water ponds.

  2. Halogen-free organophosphorus flame retardants caused oxidative stress and multixenobiotic resistance in Asian freshwater clams (Corbicula fluminea).

    Science.gov (United States)

    Yan, Saihong; Wu, Huimin; Qin, Jianhui; Zha, Jinmiao; Wang, Zijian

    2017-06-01

    Halogen-free organophosphorus flame retardants are widespread in aquatic environments. Although it has been documented that they affect the behavior and reproduction of aquatic species, researches investigating cellular detoxification and the defense system in bivalves are scarce. In this study, adult Asian clams (C. fluminea) were exposed to tris (2-butoxyethyl) phosphate (TBEP) and tributyl phosphate (TBP) at 20, 200, and 2000 μg/L for 28 d. The results showed no noticeable difference in siphoning behavior. However, the siphoning behavior displayed a trend toward a slight decrease in the treatment groups. GR activity was markedly reduced compared with the control groups, whereas the levels of cyp4 significantly increased following the 2000 μg/L TBP treatments (p fluminea mainly relies on the antioxidant system to reduce damage without an increase in MDA levels following exposure to a low concentration. Moreover, mRNA expression levels of heat shock proteins (hsp 22, 40, 60, 70, and 90) were significantly down-regulated with TBEP and TBP treatments lower than 200 μg/L (p fluminea, which kept its shell closed at high concentrations to prevent xenobiotic entry. Our results provide a new insight into the different mechanisms of cellular detoxification and the MXR system of C. fluminea in response to low and high concentrations of TBEP and TBP. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Metallothionein responses in the Asiatic clam (Corbicula fluminea) after exposure to trivalent arsenic.

    Science.gov (United States)

    Diniz, Mário S; Santos, Hugo M; Costa, Pedro M; Peres, Isabel; Costa, Maria H; Capelo, José L

    2007-01-01

    The main objective of this work was to evaluate arsenic effects on metallothionein (MT) induction by exposing a freshwater Asiatic clam (Corbicula fluminea) to different concentrations of this metalloid. The presence of MT-like proteins was detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis and compared with a standard rabbit MT. In addition, the polarographic response showed good correspondence between standard MT and MT-like curves from C. fluminea, allowing MT quantification. The results show that clams exposed to different concentrations of arsenic are able to induce significant levels of MTs. Although variability was found in MT induction, significant differences in MT levels were found after 28 days of exposure in all treatments in comparison with the controls, suggesting that exposure to arsenic induced MT-like proteins in C. fluminea.

  4. Influence of Methylmercury from Tributary Streams on Mercury Levels in Savannah River Asiatic Clams

    Energy Technology Data Exchange (ETDEWEB)

    Paller, M.H.

    2004-03-01

    Average methylmercury levels in five Savannah River tributary streams sampled 11 times over two years were nearly twice as high as in the Savannah River. Total mercury levels in the tributaries did not differ significantly from the river. All of the tributaries drained extensive wetlands that would be expected to support comparatively high rates of methylation. Mercury concentrations in Asiatic clams (Corbicula fluminea) collected from the discharge plumes of Savannah River tributaries were significantly higher than in Asiatic clams collected from the Savannah River upstream from the tributary mouths . These results indicate that streams draining wetlands into coastal plain rivers can create localized areas of elevated methylmercury with resulting increases in the mercury levels of river biota.

  5. Flux of certain radionuclides in the blood-clam Anadara granosa Linnaeus under environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Patel, B.; Patel, S.; Balani, M.C.; Pawar, S.

    1978-01-01

    The bioaccumulation of the radionuclides cesium-137, cerium-144, and ruthenium-106, and of the product nuclide cobalt-60, by arcid clams (Anadara granosa L.) in the Bombay, India, harbor was monitored from 1970-76. During the study period, the input of low level radioactive waste decreased by more than 20 times. The arcid clam showed an affinity for all three radionuclides and cobalt-60. On reaching maximum accumulation, the levels of the radionuclides decreased exponentially with time although the radioactivity was still present in sediments. The ecological half-life for cerium-144 and ruthenium-106 was 3-6 times longer, and that of cesium-137 significantly shorter, than their biological half-lives. Data on tissue distribution and rates of loss of radionuclides are presented. The bioaccumulation of the activation product cobalt-60 was independent of ambient concentration and temperature, unlike that of the three radionuclides. (7 graphs, 28 references, 7 tables)

  6. Transformation of paralytic shellfish poisoning toxins in UK surf clams (Spisula solida) for targeted production of reference materials.

    Science.gov (United States)

    Turner, Andrew D; Lewis, Adam M; O'Neil, Alison; Hatfield, Robert G

    2013-04-01

    The periodic occurrence of Paralytic Shellfish Poisoning (PSP) toxins in UK surf clams and the recent move away from biological assays for PSP testing resulted in the need to determine method performance characteristics for the replacement analytical method in this species. With the requirement for laboratory reference materials to aid this validation together with known issues relating to toxin transformation in live clams and homogenised tissue, there was the need to assess the toxin transformation characteristics of PSP toxins in surf clam tissue. Initial work examined the rates of toxin transformation in UK surf clam tissue incubated with toxin standards, showing rapid transformation of N-sulfocarbamoyl toxins with slower transformation of carbamate toxins. Full transformational pathways were determined using a combination of three different analytical methods and confirmed the major expected transformations involving decarbamoylation, with some evidence for additional reaction pathways. Results obtained from the analysis of surf clam and oyster tissues incubated with varying concentrations of toxic Alexandrium algae highlighted expected transformation reactions, although significant differences were observed in the extent of the transformations amongst the range of toxins studied, with less efficient transformation of N-hydroxylated toxins as compared with other carbamate and N-sulfocarbamoyl toxins. Analysis of PSP-toxic incurred oyster, scallop and mussel tissues incubated with variable proportions of surf clam tissue showed large differences in the extent of the transformations. Total conversion of N-sulfocarbamoyl toxins was confirmed at low relative proportions of surf clam tissue in all three species, whereas transformation of carbamate toxins was found to occur only in the presence of higher proportions of surf clam tissue in oysters and mussels in comparison with scallops. Results enabled the production of three laboratory reference materials prepared

  7. Distribution of the pill clam Pisidium langleyanum melvill & Ponsonby, 1891 (Bivalvia: Sphaeriidae) in South Africa

    OpenAIRE

    Wolmarans, Cornelius T; De Kock, Kenne N

    2008-01-01

    This article focuses on the geographical distribution and habitats of the pill clam, Pisidium langleyanum as reflected by 632 samples on record in the database of the National Freshwater Snail Collection (NFSC). The 177 different loci (1/16 -degree squares) from which these samples were collected display a relatively continuous distribution in southern Gauteng, northeastern Free State, the central area of Mpumulanga and the western part of Lesotho. However, it is discontinuously spre...

  8. Blood clams community (Anadara granoasa in The Eastern Coastal Waters of Banyuasin Regency South Sumatera

    Directory of Open Access Journals (Sweden)

    Rini Setianingsih

    2016-04-01

    Full Text Available Abstract: This research aimed to study existence of blood clams population and the environmental factors that affect them. This research was conducted in the coastal waters of Banyuasin in February 2015. The blood clamp sample was collected using Ekman Grab at low tide. From the observation in the research site, the highest population density was 60 ind/m2 with clay substrate texture, while the lowest density was 20 ind/m2 on the dusty clay substrate. Blood clams population was not found on the sand substrate texture station. Morphometric data showed that the blood clam population in the research site, including the medium category with b < 3 growth pattern (allometric negative. The results of PCA analysis proved that the habitat texture and sediment organic habitats were dominant factors besides the chemical physics environmental factors of the waters (temperature, salinity, pH. Keywords: Blood clams, density, morphometric, PCA Abstrak (Indonesian: Penelitian ini bertujuan untuk mempelajari keberadaan populasi kerang-darah dan faktor lingkungan yang mempengaruhinya. Penelitian ini dilakukan di perairan pesisir Banyuasin pada bulan Februari 2015. Sampel kerang-darah diambil dengan mengunakan Ekman Grab pada saat air surut. Dari hasil pengamatan pada lokasi penelitian, kepadatan populasi kerang-darah tertinggi adalah 60 ind/m2 dengan tekstur substrat lempung, sedangkan kepadatan terendah adalah 20 ind/m2 pada substrat lempung berdebu. Populasi kerang-darah tidak ditemukan pada stasiun dengan tekstur substrat pasir. Data morfometrik menunjukan bahwa populasi kerang-darah di lokasi penelitian termasuk kategori sedang dengan pola pertumbuhan b < 3 (allometrik negatif. Hasil analisis PCA membuktikan bahwa tekstur habitat dan bahan organik sedimen merupakan faktor dominan disamping faktor lingkungan fisika kimia perairan (suhu, salinitas, pH. Kata kunci: Kerang-darah, kepadatan, morfometrik, PCA

  9. Aerosol Optical Thicknesses Derived from Direct Solar Radiance Measurements between 350 and 2200 nm during CLAMS

    Science.gov (United States)

    Rodriguez, W. J.; Schuster, G.; Rutledge, K.; Holben, B.

    2002-05-01

    Aerosol Optical Thicknesses (AOT) were derived for the period of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field campaign using direct solar radiance measurements. The CLAMS field campaign aims to assist the validation of Earth Observing System (EOS) data products and provide a more accurate description of the shortwave radiation budget in a cloud-free earth-atmosphere system. A commercially available spectroradiometer capable of measuring solar irradiances from 350 to 2500 nm at spectral intervals of 1 nm and time intervals as low as one second was utilized. This spectroradiometer is capable of providing direct solar radiances of 92 percent of the solar spectrum every second offering a dramatic increase in the amount of spectral and temporal information as compared to the conventionally used filter-based radiometers. This wealth of information could be utilized to monitor rapid variations in aerosol optical properties and other atmospheric species, e.g. water vapor. High altitude radiometric calibrations were performed prior to CLAMS to ensure the accuracy of the data. Results from this instrument as compared with a thoroughly calibrated and tested filtered-based instrument show good agreement in the days of interest. On July 17, 2001, the day where all the parties involved in the mission (satellite, airplane, and ground) acquired exceptional data, AOTs show values fluctuating from 0.49 to 0.44 at 500 nm and from 0.1 to .08 at 1020 nm. Alpha values derived for the visible wavelength range steadily increased throughout morning from 2.0 to 2.4 consistent with the presence of aerosols from continental air masses. The aerosol optical properties derived from this instrument are being utilized to validate and complement aircraft and satellite instrument data in the context of the CLAMS mission.

  10. Microbiota and environmental stress: how pollution affects microbial communities in Manila clams.

    Science.gov (United States)

    Milan, M; Carraro, L; Fariselli, P; Martino, M E; Cavalieri, D; Vitali, F; Boffo, L; Patarnello, T; Bargelloni, L; Cardazzo, B

    2018-01-01

    Given the crucial role of microbiota in host development, health, and environmental interactions, genomic analyses focusing on host-microbiota interactions should certainly be considered in the investigation of the adaptive mechanisms to environmental stress. Recently, several studies suggested that microbiota associated to digestive tract is a key, although still not fully understood, player that must be considered to assess the toxicity of environmental contaminants. Bacteria-dependent metabolism of xenobiotics may indeed modulate the host toxicity. Conversely, environmental variables (including pollution) may alter the microbial community and/or its metabolic activity leading to host physiological alterations that may contribute to their toxicity. Here, 16s rRNA gene amplicon sequencing has been applied to characterize the hepatopancreas microbiota composition of the Manila clam, Ruditapes philippinarum. The animals were collected in the Venice lagoon area, which is subject to different anthropogenic pressures, mainly represented by the industrial activities of Porto Marghera (PM). Seasonal and geographic differences in clam microbiotas were explored and linked to host response to chemical stress identified in a previous study at the transcriptome level, establishing potential interactions among hosts, microbes, and environmental parameters. The obtained results showed the recurrent presence of putatively detoxifying bacterial taxa in PM clams during winter and over-representation of several metabolic pathways involved in xenobiotic degradation, which suggested the potential for host-microbial synergistic detoxifying actions. Strong interaction between seasonal and chemically-induced responses was also observed, which partially obscured such potentially synergistic actions. Seasonal variables and exposure to toxicants were therefore shown to interact and substantially affect clam microbiota, which appeared to mirror host response to environmental variation. It

  11. Multi-species generalist predation on the stochastic harvested clam Tivela mactroides (Mollusca, Bivalvia)

    Science.gov (United States)

    Turra, Alexander; Fernandez, Wellington S.; Bessa, Eduardo; Santos, Flavia B.; Denadai, Márcia R.

    2015-12-01

    Top-down control is an important force modulating the abundance of prey and structuring marine communities. The harvested trigonal clam Tivela mactroides is hypothesized to be part of the diet of a variety of marine organisms, with its stock influencing predator abundance and being influenced by them. Here we analyzed the diet of potential predators of T. mactroides in Caraguatatuba Bay, northern coast of São Paulo State, Brazil, to identify the main consumers of this marine resource, and also to address the importance of this clam in the diet of each predator. Samples were taken year-round by trawls; all specimens collected were identified and measured and the food items identified and quantified. Twenty-one species consumed T. mactroides, whose importance in the diet varied greatly in both the volume ingested and the frequency of occurrence (pompano Trachinotus carolinus > blue crab Callinectes danae > starfish Astropecten marginatus). Top-down influence on T. mactroides was also dependent on the abundance of consumers (yellow catfish Cathorops spixii > rake stardrum Stellifer rastrifer > barred grunt Conodon nobilis > A. marginatus). Considering the mean volume ingested, the frequency of occurrence of T. mactroides in the diet, and the relative abundance of consumers, the predators that most influenced T. mactroides were T. carolinus, A. marginatus, and C. danae, in decreasing order. Large numbers of small-sized individuals of T. mactroides (<10 mm) were generally preyed upon by A. marginatus, which may have a stronger effect on clam abundance in comparison to C. danae and T. carolinus, which preyed upon larger clams. In conclusion, the results of this study indicate that predators' consumption of T. mactroides in Caraguatatuba Bay can influence its stocks, mainly due to the type and/or abundance of predator species, the volume and number of individuals of T. mactroides preyed upon, and the temporal variations in the abundance of predators.

  12. Acute and chronic exposure in mussel (aulacomya ater) and clam (semelle solida) with Cs137

    International Nuclear Information System (INIS)

    Bringas, J.E.

    1996-01-01

    Two of the most common Peruvian benthonic molluscs, have been shown to be effective concentrators of Cesium-137 and have also proven useful as indicators of that radionuclide in their natural environment, according with results in this paper. However the clam is a better indicator, when determining environmental acute release of Cesium-137 due to reactor accidents, nuclear tests, accidents in nuclear ships, submarines and radioactive material transport, and the mussel for a continuous monitoring of environmental radio contaminant levels. (author). 11 refs

  13. Clam-Gallasův palác - emblematická architektura?

    Czech Academy of Sciences Publication Activity Database

    Konečný, Lubomír

    2009-01-01

    Roč. 28, - (2009), s. 91-98 ISSN 0231-7443. [Život pražských paláců. Praha, 09.10.2007-11.10.2007] Institutional research plan: CEZ:AV0Z80330511 Keywords : Clam-Gallas Palace * Johann Bernhard Fischer von Erlach * architecture * emblem s * imprints Subject RIV: AL - Art, Architecture, Cultural Heritage

  14. Assessment of relationship between rainfall and Escherichia coli in clams (Chamelea gallina) using the Bayes Factor.

    Science.gov (United States)

    Ciccarelli, Cesare; Semeraro, Angela Marisa; Leinoudi, Melina; Trani, Vittoria Di; Murru, Sandra; Capocasa, Piero; Ciccarelli, Elena; Sacchini, Luca

    2017-08-16

    Consumption of bivalve shellfish harvested from water contaminated with sewage pollution presents a risk of human infections and targeting control measures require a good understanding of environmental factors influencing the transport and the fate of faecal contaminants within the hydrological catchments. Although there has been extensive development of regression models, the point of this paper, focused on the relationship between rainfall events and concentrations of Escherichia coli monitored in clams, was the use of a Bayesian approach, by the Bayes Factor. The study was conducted on clams harvested from the south coast of Marche Region (Italy), a coastal area impacted by continuous treated effluents, intermittent rainfalldependent untreated sewage spillage - as a consequence of stormwater overflowing - and rivers with an ephemeral flow regime. The work compared the different interpretation criteria of Bayes Factor, confirmed that E. coli concentrations in clams from the studied area varied in correlation with rainfall events, and demonstrated the effectiveness of Bayes Factor in the assessment of shellfish quality in coastal marine waters. However, it suggested that further investigations would be warranted to determine which environmental factors provide the better basis for accurate and timely predictions. Furthermore the gathered data could be useful, to the local authorities of Marche Region, in the definition of flexible monitoring programmes, taking into account the atmospheric events that could affect the correct functioning of sewage managing systems and the flow of tributary rivers.

  15. Histopathology and stress biomarkers in the clam Venerupis philippinarum from the Venice Lagoon (Italy).

    Science.gov (United States)

    Boscolo Papo, Michele; Bertotto, Daniela; Quaglio, Francesco; Vascellari, Marta; Pascoli, Francesco; Negrato, Elena; Binato, Giovanni; Radaelli, Giuseppe

    2014-07-01

    The aim of this study was to evaluate the histomorphology and the stress response in the bivalve Venerupis philippinarum sampled in four differently polluted sites of the Venice Lagoon (Palude del Monte, Marghera, Ca' Roman and Val di Brenta). This species is often used as bioindicator of environmental pollution since it can bioaccumulate a large variety of pollutants because of its filter feeding. Chemical analyses for heavy metals (Cd, Cu, Hg and Pb) and polycyclic aromatic hydrocarbons (PAHs) were performed on whole soft tissues of V. philippinarum. The histological evaluation of clams revealed the presence of Perkinsus sp. infection in animals from all sites, although a very high prevalence of parasites was evidenced in clams from Ca' Roman. Perkinsus sp. were systemically distributed in the mantle, in the intestine and digestive gland, in gonads and gills. The trophozoites of Perkinsus sp. were found isolated or in cluster surrounded by a heavy hemocitical response. Haemocytes always exhibited an immunopositivity to cytochrome P4501A (CYP1A), heat shock protein 70 (HSP70), 4-hydroxy-2-nonenal (HNE) and nitrotyrosine (NT) antibodies. The digestive gland of animals from Palude del Monte showed the highest malondialdehyde (MDA) concentration, whereas clams from Ca' Roman exhibited the highest quantity of metallothioneins. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Influence of thermal aging on microstructure and mechanical properties of CLAM steel

    Science.gov (United States)

    Huang, Lixin; Hu, Xue; Yang, Chunguang; Yan, Wei; Xiao, Furen; Shan, Yiyin; Yang, Ke

    2013-11-01

    In order to investigate the influence of thermal aging on microstructure and mechanical properties of CLAM (China low activation martensitic) steel, a comparison study was made on the as-tempered and the aged steels. The tempered CLAM steels were subjected to aging treatment at 600 °C for 1100 h and 3000 h, and at 650 °C for 1100 h, respectively. The changes of microstructure were characterized by both transmission electron microscope (TEM) and scanning electron microscope (SEM). The mechanical properties were evaluated by Charpy impact, tensile and Vickers hardness tests. The upper shelf energy (USE) of the thermal aged CLAM steel decreased with the extension of aging time, while the yield strength changed slightly. After long-term thermal aging, the MX type precipitates remained stable. The coarsening of M23C6 and the formation of Laves phase were confirmed by scanning/transmission electron microscopes. The Laves phase was the main factor leading to the increase of DBTT.

  17. Assessment of relationship between rainfall and Escherichia coli in clams (Chamelea gallina using the Bayes Factor

    Directory of Open Access Journals (Sweden)

    Cesare Ciccarelli

    2017-08-01

    Full Text Available Consumption of bivalve shellfish harvested from water contaminated with sewage pollution presents a risk of human infections and targeting control measures require a good understanding of environmental factors influencing the transport and the fate of faecal contaminants within the hydrological catchments. Although there has been extensive development of regression models, the point of this paper, focused on the relationship between rainfall events and concentrations of Escherichia coli monitored in clams, was the use of a Bayesian approach, by the Bayes Factor. The study was conducted on clams harvested from the south coast of Marche Region (Italy, a coastal area impacted by continuous treated effluents, intermittent rainfalldependent untreated sewage spillage - as a consequence of stormwater overflowing - and rivers with an ephemeral flow regime. The work compared the different interpretation criteria of Bayes Factor, confirmed that E. coli concentrations in clams from the studied area varied in correlation with rainfall events, and demonstrated the effectiveness of Bayes Factor in the assessment of shellfish quality in coastal marine waters. However, it suggested that further investigations would be warranted to determine which environmental factors provide the better basis for accurate and timely predictions. Furthermore the gathered data could be useful, to the local authorities of Marche Region, in the definition of flexible monitoring programmes, taking into account the atmospheric events that could affect the correct functioning of sewage managing systems and the flow of tributary rivers.

  18. Modeling habitat suitability of the invasive clam Corbicula fluminea in a Neotropical shallow lagoon, southern Brazil.

    Science.gov (United States)

    Silveira, T C L; Gama, A M S; Alves, T P; Fontoura, N F

    2016-04-19

    This study aimed to model the habitat suitability for an invasive clam Corbicula fluminea in a coastal shallow lagoon in the southern Neotropical region (-30.22, -50.55). The lagoon (19km2, maximum deep 2.5m) was sampled with an Ekman dredge in an orthogonal matrix comprising 84 points. At each sampling point, were obtained environmental descriptors as depth, organic matter content (OMC), average granulometry (Avgran), and the percentage of sand (Pcsand). Prediction performance of Generalized Linear Models (GLM), Generalized Additive Models (GAM) and Boosted Regression Tree (BRT) were compared. Also, niche overlapping with other native clam species (Castalia martensi, Neocorbicula limosa and Anodontites trapesialis) was examined. A BRT model with 1400 trees was selected as the best model, with cross-validated correlation of 0.82. The relative contributions of predictors were Pcsand-42.6%, OMC-35.8%, Avgran-10.9% and Depth-10.8%. Were identified that C. fluminea occur mainly in sandy sediments with few organic matter, in shallow areas nor by the shore. The PCA showed a wide niche overlap with the native clam species C. martensi, N. limosa and A. trapesialis.

  19. Triangular gold nanoparticles modify shell characteristics and increase antioxidant enzyme activities in the clam Ruditapes decussatus.

    Science.gov (United States)

    Abdelhafidh, Khazri; Badreddine, Sellami; Mezni, Amine; Mouhamed, Dellali; Wiem, Saidani; Imen, Bouzidi; David, Sheehan; Mahmoudi, Ezzeddine; Hamouda, Beyrem

    2018-04-19

    Nanoparticles may cause adverse environmental effects but there is limited information on their interactions with marine organisms. Our aim was to examine the effects of triangular gold nanoparticles (Tr-Au NPs) on the clam, Ruditapes decussatus. Clams were exposed to Tr-Au1 = 5 µg/L and Tr-Au2 = 10 µg/L for 2 and 7 days. Effects on shell structure were investigated. Superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GST) activities, protein carbonyl levels and malondialdehyde content were used to assess biochemical status. Transmission electron microscopy (TEM) and electron dispersive X-ray microanalysis (EDX) showed that Tr-Au NPs modified shell structure and morphology. Tr-Au NPs size increased forming aggregate particles. Tr-Au NPs increased SOD, CAT and GST activities in gill and digestive gland in a concentration- and time-dependent manner indicating defence against oxidative stress. Enhanced lipid peroxidation and protein carbonyl levels confirmed oxidative stress. Tr-Au NPs cause oxidative stress and affect shell structure of clams. These findings may have relevance to other marine species.

  20. Modeling habitat suitability of the invasive clam Corbicula fluminea in a Neotropical shallow lagoon, southern Brazil

    Directory of Open Access Journals (Sweden)

    T. C. L. Silveira

    Full Text Available Abstract This study aimed to model the habitat suitability for an invasive clam Corbicula fluminea in a coastal shallow lagoon in the southern Neotropical region (–30.22, –50.55. The lagoon (19km2, maximum deep 2.5m was sampled with an Ekman dredge in an orthogonal matrix comprising 84 points. At each sampling point, were obtained environmental descriptors as depth, organic matter content (OMC, average granulometry (Avgran, and the percentage of sand (Pcsand. Prediction performance of Generalized Linear Models (GLM, Generalized Additive Models (GAM and Boosted Regression Tree (BRT were compared. Also, niche overlapping with other native clam species (Castalia martensi, Neocorbicula limosa and Anodontites trapesialis was examined. A BRT model with 1400 trees was selected as the best model, with cross-validated correlation of 0.82. The relative contributions of predictors were Pcsand-42.6%, OMC-35.8%, Avgran-10.9% and Depth-10.8%. Were identified that C. fluminea occur mainly in sandy sediments with few organic matter, in shallow areas nor by the shore. The PCA showed a wide niche overlap with the native clam species C. martensi, N. limosa and A. trapesialis.

  1. Irradiation control of pathogenic bacteria and their growth during storage in short neckde clam

    International Nuclear Information System (INIS)

    Ju Hua; Wang Feng; Ha Yiming; Liu Shuliang

    2009-01-01

    The growth of pathogenic bacteria during storage and their D 10 values by irradiation in short necked clam were evaluated. The results showed that the D 10 values of the total bacteria count, E. coli, Vibrio parahaemolyticus in short necked clam at 0 degree C ∼ 4 degree C condition were 0.70, 0.56, 0.20kGy, respectively. The results showed that total bacteria count in vacuum packaged short necked clam sample was 4.46 log (CFU/g) after 3kGy 60 Co γ-irradiation and 28 days stored under 0 degree C ∼ 4 degree C, which could meet the requirement of related aquatic product standards, the E. coli and Vibrio parahaemolyticus would not detected after 0.4kGy irradiation and 7 days storage at 0 degree C ∼ 4 degree C. Therefore, micro-organisms could be controled effectively by 3 kGy irradiation and its shelf-life could extend to 28 days. (authors)

  2. Effect of okadaic acid on cultured clam heart cells: involvement of MAPkinase pathways

    Directory of Open Access Journals (Sweden)

    Houda Hanana

    2012-09-01

    Okadaic acid (OA is one of the main diarrhetic shellfish poisoning toxins and a potent inhibitor of protein phosphatases 1 and 2A. The downstream signal transduction pathways following the protein phosphatase inhibition are still unknown and the results of most of the previous studies are often conflicting. The aim of the present study was to evaluate the effects of OA on heart clam cells and to analyse its possible mechanisms of action by investigating the signal transduction pathways involved in OA cytotoxicity. We showed that OA at 1 µM after 24 h of treatment induces disorganization of the actin cytoskeleton, rounding and detachment of fibroblastic cells. Moreover, treatment of heart cells revealed a sequential activation of MAPK proteins depending on the OA concentration. We suggest that the duration of p38 and JNK activation is a critical factor in determining cell apoptosis in clam cardiomyocytes. In the opposite, ERK activation could be involved in cell survival. The cell death induced by OA is a MAPK modulated pathway, mediated by caspase 3-dependent mechanism. OA was found to induce no significant effect on spontaneous beating rate or inward L-type calcium current in clam cardiomyocytes, suggesting that PP1 was not inhibited even by the highest dose of OA.

  3. Giant Clams and Rising CO2: Light May Ameliorate Effects of Ocean Acidification on a Solar-Powered Animal.

    Directory of Open Access Journals (Sweden)

    Sue-Ann Watson

    Full Text Available Global climate change and ocean acidification pose a serious threat to marine life. Marine invertebrates are particularly susceptible to ocean acidification, especially highly calcareous taxa such as molluscs, echinoderms and corals. The largest of all bivalve molluscs, giant clams, are already threatened by a variety of local pressures, including overharvesting, and are in decline worldwide. Several giant clam species are listed as 'Vulnerable' on the IUCN Red List of Threatened Species and now climate change and ocean acidification pose an additional threat to their conservation. Unlike most other molluscs, giant clams are 'solar-powered' animals containing photosynthetic algal symbionts suggesting that light could influence the effects of ocean acidification on these vulnerable animals. In this study, juvenile fluted giant clams Tridacna squamosa were exposed to three levels of carbon dioxide (CO2 (control ~400, mid ~650 and high ~950 μatm and light (photosynthetically active radiation 35, 65 and 304 μmol photons m-2 s-1. Elevated CO2 projected for the end of this century (~650 and ~950 μatm reduced giant clam survival and growth at mid-light levels. However, effects of CO2 on survival were absent at high-light, with 100% survival across all CO2 levels. Effects of CO2 on growth of surviving clams were lessened, but not removed, at high-light levels. Shell growth and total animal mass gain were still reduced at high-CO2. This study demonstrates the potential for light to alleviate effects of ocean acidification on survival and growth in a threatened calcareous marine invertebrate. Managing water quality (e.g. turbidity and sedimentation in coastal areas to maintain water clarity may help ameliorate some negative effects of ocean acidification on giant clams and potentially other solar-powered calcifiers, such as hard corals.

  4. Giant Clams and Rising CO2: Light May Ameliorate Effects of Ocean Acidification on a Solar-Powered Animal.

    Science.gov (United States)

    Watson, Sue-Ann

    2015-01-01

    Global climate change and ocean acidification pose a serious threat to marine life. Marine invertebrates are particularly susceptible to ocean acidification, especially highly calcareous taxa such as molluscs, echinoderms and corals. The largest of all bivalve molluscs, giant clams, are already threatened by a variety of local pressures, including overharvesting, and are in decline worldwide. Several giant clam species are listed as 'Vulnerable' on the IUCN Red List of Threatened Species and now climate change and ocean acidification pose an additional threat to their conservation. Unlike most other molluscs, giant clams are 'solar-powered' animals containing photosynthetic algal symbionts suggesting that light could influence the effects of ocean acidification on these vulnerable animals. In this study, juvenile fluted giant clams Tridacna squamosa were exposed to three levels of carbon dioxide (CO2) (control ~400, mid ~650 and high ~950 μatm) and light (photosynthetically active radiation 35, 65 and 304 μmol photons m-2 s-1). Elevated CO2 projected for the end of this century (~650 and ~950 μatm) reduced giant clam survival and growth at mid-light levels. However, effects of CO2 on survival were absent at high-light, with 100% survival across all CO2 levels. Effects of CO2 on growth of surviving clams were lessened, but not removed, at high-light levels. Shell growth and total animal mass gain were still reduced at high-CO2. This study demonstrates the potential for light to alleviate effects of ocean acidification on survival and growth in a threatened calcareous marine invertebrate. Managing water quality (e.g. turbidity and sedimentation) in coastal areas to maintain water clarity may help ameliorate some negative effects of ocean acidification on giant clams and potentially other solar-powered calcifiers, such as hard corals.

  5. Growth and Histological Effects to Protothaca staminea (Littleneck Clam) of Long-Term Exposure to Chlorinated Sea Water

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, C. I.; Hillman, A. E.; Wilkinson, P.; Woodruff, D. L.

    1980-08-01

    There has been considerable concern about the potential for long-term effects to marine organisms from chlorinated sea water. As part of a larger study to investigate the effects of materials resulting from seawater chlorination on marine organisms, groups of littleneck clams, Protothaca staminea, were exposed to sea water that had been chlorinated. Two experiments were conducted. In one test, groups of littleneck clams were exposed to dilutions of chlorinated sea water that had average chlorine produced oxidant (CPO) concentrations of 16 {micro}g/l or less. In the second test, groups of clams were exposed to chlorinated seawater-unchlorinated seawater mixtures that had target CPO concentrations of 0, 6, 12, 25, 50 and 100 {micro}g/l. In the first experiment, length measurements were made on all clams at approximately one-month intervals for three months. In the second test, length, weight, depth, width and edge etching were used to measure growth, and subsamples were harvested and measured at one-month intervals. In addition, clams were preserved for histological examination. The clams in the first experiment all had negative growth. In the second test, growth was inhibited under all conditions through the first four months of exposure. During the last four months, there was positive signs of growth at the 0, 6 and 12 {micro}g/l CPO test conditions. Histological examination indicates that P. staminea does not adapt well to being held in aquaria. Most clams, tram all test and control conditions, showed evidence of necrosis at one month. This condition seemed to improve with longer exposure at lower CPO concentrations but persisted at CPO concentrations of 25 {micro}g/l and higher. Other histological effects were apparent at the higher exposure concentrations as the length of exposure increased.

  6. Acidified seawater increases accumulation of cobalt but not cesium in manila clam Ruditapes philippinarum.

    Science.gov (United States)

    Sezer, Narin; Kocaoğlan, Hasan Oğuz; Kılıç, Önder; Lacoue-Labarthe, Thomas; Belivermiş, Murat

    2018-04-01

    The pH of seawater around the world is expected to continue its decline in the near future in response to ocean acidification that is driven by heightened atmospheric CO 2 emissions. Concomitantly, economically-important molluscs that live in coastal waters including estuaries and embayments, may be exposed to a wide assortment of contaminants, including trace metals and radionuclides. Seawater acidification may alter both the chemical speciation of select elements as well as the physiology of organisms, and may thus pose at risk to many shellfish species, including the manila clam Ruditapes philippinarum. The bioconcentration efficiency of two common radionuclides associated with the nuclear fuel cycle, 134 Cs and 57 Co, were investigated by exposing live clams to dissolved 134 Cs and 57 Co at control (pH = 8.1) and two lowered pH (pH = 7.8 and 7.5) levels using controlled aquaria. The uptake and depuration kinetics of the two radionuclides in the whole-body clam were followed for 21 and 35 days, respectively. At steady-state equilibrium, the concentration factor (CF ss ) for 57 Co increased as the pH decreased (i.e. 130 ± 5, 194 ± 6, and 258 ± 10 at pH levels 8.1, 7.8 and 7.5, respectively), whereas the 134 Cs uptake was not influenced by a change in pH conditions. During depuration, the lowest depuration rate constant of 57 Co by the manila clam was observed at the intermediate pH of 7.8. An increase in the accumulation of 57 Co at the intermediate pH value was thought to be caused mainly by the aragonitic shell of the clam, as well as the low salinity and alkalinity of seawater used in the experiment. Considering that accumulation consists of uptake and depuration, among the three pH conditions moderately acidified seawater enhanced most the accumulation of 57 Co. Accumulation of 134 Cs was not strongly influenced by a reduced pH condition, as represented by an analogous uptake constant rate and CF ss in each treatment. Such results suggest that

  7. A novel approach for acid mine drainage pollution biomonitoring using rare earth elements bioaccumulated in the freshwater clam Corbicula fluminea.

    Science.gov (United States)

    Bonnail, Estefanía; Pérez-López, Rafael; Sarmiento, Aguasanta M; Nieto, José Miguel; DelValls, T Ángel

    2017-09-15

    Lanthanide series have been used as a record of the water-rock interaction and work as a tool for identifying impacts of acid mine drainage (lixiviate residue derived from sulphide oxidation). The application of North-American Shale Composite-normalized rare earth elements patterns to these minority elements allows determining the origin of the contamination. In the current study, geochemical patterns were applied to rare earth elements bioaccumulated in the soft tissue of the freshwater clam Corbicula fluminea after exposure to different acid mine drainage contaminated environments. Results show significant bioaccumulation of rare earth elements in soft tissue of the clam after 14 days of exposure to acid mine drainage contaminated sediment (ΣREE=1.3-8μg/gdw). Furthermore, it was possible to biomonitor different degrees of contamination based on rare earth elements in tissue. The pattern of this type of contamination describes a particular curve characterized by an enrichment in the middle rare earth elements; a homologous pattern (E MREE =0.90) has also been observed when applied NASC normalization in clam tissues. Results of lanthanides found in clams were contrasted with the paucity of toxicity studies, determining risk caused by light rare earth elements in the Odiel River close to the Estuary. The current study purposes the use of clam as an innovative "bio-tool" for the biogeochemical monitoring of pollution inputs that determines the acid mine drainage networks affection. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Purification and Characterization of Hemagglutinating Proteins from Poker-Chip Venus (Meretrix lusoria and Corbicula Clam (Corbicula fluminea

    Directory of Open Access Journals (Sweden)

    Chin-Fu Cheng

    2012-01-01

    Full Text Available Hemagglutinating proteins (HAPs were purified from Poker-chip Venus (Meretrix lusoria and Corbicula clam (Corbicula fluminea using gel-filtration chromatography on a Sephacryl S-300 column. The molecular weights of the HAPs obtained from Poker-chip Venus and Corbicula clam were 358 kDa and 380 kDa, respectively. Purified HAP from Poker-chip Venus yielded two subunits with molecular weights of 26 kDa and 29 kDa. However, only one HAP subunit was purified from Corbicula clam, and its molecular weight was 32 kDa. The two Poker-chip Venus HAPs possessed hemagglutinating ability (HAA for erythrocytes of some vertebrate animal species, especially tilapia. Moreover, HAA of the HAP purified from Poker-chip Venus was higher than that of the HAP of Corbicula clam. Furthermore, Poker-chip Venus HAPs possessed better HAA at a pH higher than 7.0. When the temperature was at 4°C–10°C or the salinity was less than 0.5‰, the two Poker-chip Venus HAPs possessed better HAA compared with that of Corbicula clam.

  9. Purification and characterization of hemagglutinating proteins from Poker-chip Venus (Meretrix lusoria) and Corbicula clam (Corbicula fluminea).

    Science.gov (United States)

    Cheng, Chin-Fu; Hung, Shao-Wen; Chang, Yung-Chung; Chen, Ming-Hui; Chang, Chen-Hsuan; Tsou, Li-Tse; Tu, Ching-Yu; Lin, Yu-Hsing; Liu, Pan-Chen; Lin, Shiun-Long; Wang, Way-Shyan

    2012-01-01

    Hemagglutinating proteins (HAPs) were purified from Poker-chip Venus (Meretrix lusoria) and Corbicula clam (Corbicula fluminea) using gel-filtration chromatography on a Sephacryl S-300 column. The molecular weights of the HAPs obtained from Poker-chip Venus and Corbicula clam were 358 kDa and 380 kDa, respectively. Purified HAP from Poker-chip Venus yielded two subunits with molecular weights of 26 kDa and 29 kDa. However, only one HAP subunit was purified from Corbicula clam, and its molecular weight was 32 kDa. The two Poker-chip Venus HAPs possessed hemagglutinating ability (HAA) for erythrocytes of some vertebrate animal species, especially tilapia. Moreover, HAA of the HAP purified from Poker-chip Venus was higher than that of the HAP of Corbicula clam. Furthermore, Poker-chip Venus HAPs possessed better HAA at a pH higher than 7.0. When the temperature was at 4°C-10°C or the salinity was less than 0.5‰, the two Poker-chip Venus HAPs possessed better HAA compared with that of Corbicula clam.

  10. Bioaccumulation of polychlorinated biphenyls and metals from contaminated sediment by freshwater prawns, Macrobrachium rosenbergii and clams, Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Tatem, H.E.

    1986-02-01

    Freshwater prawns, Macrobrachium rosenbergii, and clams, Corbicula Fluminea, were exposed for 48 or 50 days to three concentrations of a river sediment that contained environmental contaminants such as polychlorinated biphenyls (PCBs) and metals. The PCB sediment bioaccumulation factors (BAF) for prawns ranged from 0.11 to 0.90 for 1242 and 0.20 to 2.40 for 1254, and were highest for animals exposed to 10% sediment. Exposed clams also accumulated PCBs (1242 + 1254) from the sediment. Sediment BAFs for clams were 0.54 to 12.52 and were highest for animals exposed to 10% sediment. Analyses of clams for metals showed lead (Pb) in exposed animals at higher concentrations compared with controls. Bioaccumulation of Pb differed from PCB in that the Pb concentrations did not increase over time and concentrations were higher among animals exposed to 10% sediment compared to animals exposed to 100% sediment. Sediment 11-80 contained 99 mg/kg of Pb while exposed animals, at 48 days, contained approximately 2.2 mg/kg Pb. Analysis of clams for cadmium (Cd) showed exposed animals contained less Cd than controls.

  11. NMR-Based Metabolomic Investigations on the Differential Responses in Adductor Muscles from Two Pedigrees of Manila Clam Ruditapes philippinarum to Cadmium and Zinc

    Directory of Open Access Journals (Sweden)

    Junbao Yu

    2011-09-01

    Full Text Available Manila clam Ruditapes philippinarum is one of the most important economic species in shellfishery in China due to its wide geographic distribution and high tolerance to environmental changes (e.g., salinity, temperature. In addition, Manila clam is a good biomonitor/bioindicator in “Mussel Watch Programs” and marine environmental toxicology. However, there are several pedigrees of R. philippinarum distributed in the marine environment in China. No attention has been paid to the biological differences between various pedigrees of Manila clams, which may introduce undesirable biological variation in toxicology studies. In this study, we applied NMR-based metabolomics to detect the biological differences in two main pedigrees (White and Zebra of R. philippinarum and their differential responses to heavy metal exposures (Cadmium and Zinc using adductor muscle as a target tissue to define one sensitive pedigree of R. philippinarum as biomonitor for heavy metals. Our results indicated that there were significant metabolic differences in adductor muscle tissues between White and Zebra clams, including higher levels of alanine, glutamine, hypotaurine, phosphocholine and homarine in White clam muscles and higher levels of branched chain amino acids (valine, leucine and isoleucine, succinate and 4-aminobutyrate in Zebra clam muscles, respectively. Differential metabolic responses to heavy metals between White and Zebra clams were also found. Overall, we concluded that White pedigree of clam could be a preferable bioindicator/biomonitor in marine toxicology studies and for marine heavy metals based on the relatively high sensitivity to heavy metals.

  12. Evaluation of Using Caged Clams to Monitor Contaminated Groundwater Exposure in the Near-Shore Environment of the Hanford Site 300 Area

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Kyle B.; Poston, Ted M.; Tiller, Brett L.

    2008-01-31

    The Asiatic clam (Corbicula fluminea) has been identified as an indicator species for locating and monitoring contaminated groundwater in the Columbia River. Pacific Northwest National Laboratory conducted a field study to explore the use of caged Asiatic clams to monitor contaminated groundwater upwelling in the 300 Area near-shore environment and assess seasonal differences in uranium uptake in relation to seasonal flow regimes of the Columbia River. Additional objectives included examining the potential effects of uranium accumulation on growth, survival, and tissue condition of the clams. This report documents the field conditions and procedures, laboratory procedures, and statistical analyses used in collecting samples and processing the data. Detailed results are presented and illustrated, followed by a discussion comparing uranium concentrations in Asiatic clams collected at the 300 Area and describing the relationship between river discharge, groundwater indicators, and uranium in clams. Growth and survival, histology, and other sources of environmental variation also are discussed.

  13. Verification of the effect of surface preparation on Hot Isostatic Pressing diffusion bonding joints of CLAM steel

    Science.gov (United States)

    Zhao, Yanyun; Li, Chunjing; Huang, Bo; Liu, Shaojun; Huang, Qunying

    2014-12-01

    Hot Isostatic Pressing (HIP) diffusion bonding with CLAM steel is the primary candidate fabrication technique for the first wall (FW) of DFLL-TBM. Surface state is one of the key factors for the joints quality. The effect of surface state prepared with grinder and miller on HIP diffusion bonding joints of CLAM steel was investigated. HIP diffusion bonding was performed at 140 MPa and 1373 K within 3 h. The mechanical properties of the joints were investigated with instrumented Charpy V-notch impact tests and the microstructures of the joints were analyzed with scanning electron microscopy (SEM). The results showed that the milled samples with fine surface roughness were more suitable for CLAM steel HIP diffusion bonding.

  14. Size-dependent effects of low level cadmium and zinc exposure on the metabolome of the Asian clam, Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Spann, Nicole, E-mail: nicole.spann@web.de [Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ (United Kingdom); Aldridge, David C., E-mail: da113@cam.ac.uk [Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ (United Kingdom); Griffin, Julian L., E-mail: jlg40@mole.bio.cam.ac.uk [Sanger Building, Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA (United Kingdom); Jones, Oliver A.H., E-mail: o.jones@gmail.com [Sanger Building, Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA (United Kingdom)

    2011-10-15

    Highlights: Small and large Corbicula fluminea were exposed to cadmium and zinc spiked sediment. Metabolomic changes in the freshwater clams were determined by NMR and GC-MS. Metabolic perturbations were related to amino acid and energy related metabolism. Small and large clams were differentiated by their metabolic composition. Size classes showed opposite responses to metal stress. - Abstract: The toxic effects of low level metal contamination in sediments are currently poorly understood. We exposed different sized Asian clams, Corbicula fluminea, to sediment spiked with environmentally relevant concentrations of either zinc, cadmium or a zinc-cadmium mixture for one week. This freshwater bivalve is well suited for sediment toxicity tests as it lives partly buried in the sediment and utilises sediment particles as a food resource. After one week, the whole tissue composition of low molecular weight metabolites was analysed by nuclear magnetic resonance spectroscopy (NMR) and gas chromatography-mass spectrometry (GC-MS). The condition index (ratio of tissue dry weight to volume inside the shell valves) was also measured. Small and large clams were clearly differentiated by their metabolic composition and the two size classes showed opposite responses to the mixture spiked sediment. No effects of zinc alone on the metabolome were found and cadmium only influenced the smaller size class. The main perturbations were seen in amino acid and energy metabolism, with small clams using amino acids as an energy resource and larger clams primarily drawing on their larger storage reserves of carbohydrates. Our study demonstrates that metabolomics is a useful technique to test for low level toxicity which does not manifest in mortality or condition index changes. The differing effects between the two size classes stress that it is important to consider age/size when conducting metabolomic and ecotoxicology assessments, since testing for the effects on only one size class makes

  15. High contribution of the particulate uptake pathway to metal bioaccumulation in the tropical marine clam Gafrarium pectinatum.

    Science.gov (United States)

    Hédouin, Laetitia; Metian, Marc; Teyssié, Jean-Louis; Fichez, Renaud; Warnau, Michel

    2017-03-09

    The clam Gafrarium pectinatum was investigated to assess its usefulness as a bioindicator species of metal mining contamination in the New Caledonia lagoon. The uptake and depuration kinetics of Ag, Cd, Co, Cr, and Zn were determined following exposures via seawater, sediment, and food using highly sensitive radiotracer techniques ( 110m Ag, 109 Cd, 51 Cr, 57 Co, and 65 Zn). When the clams were exposed to dissolved metals, Co, Zn, and Ag were readily incorporated in their tissues (concentration factors (CF) ranging from 181 to 4982 after 28 days of exposure) and all metals were strongly retained (biological half-lives always >2 months). The estimated transfer factor (TF) in clam tissues after a 35-day sediment exposure was 1 to 4 orders of magnitude lower than the estimated CF, indicating a lower bioavailability of sediment-bound metals than dissolved ones. Once incorporated, metals taken up from sediment and seawater were retained longer than metals ingested with food, indicating that the uptake pathway influences the storage processes of metals in clam tissues. Compilation of our data into a global bioaccumulation model indicated that, except for Ag that essentially originated from food (92%), sediment was the main source of metal bioaccumulation in the clam (more than 80%). These results highlight that bioaccumulation processes strongly depend from one metal to the other. The overall efficient bioaccumulation and retention capacities of the clam G. pectinatum confirm its usefulness as a bioindicator species that can provide time-integrated information about ambient contamination levels in the tropical marine coastal environment.

  16. Sequencing and characterization of striped venus transcriptome expand resources for clam fishery genetics.

    Directory of Open Access Journals (Sweden)

    Alessandro Coppe

    Full Text Available BACKGROUND: The striped venus Chamelea gallina clam fishery is among the oldest and the largest in the Mediterranean Sea, particularly in the inshore waters of northern Adriatic Sea. The high fishing pressure has lead to a strong stock abundance decline, enhanced by several irregular mortality events. The nearly complete lack of molecular characterization limits the available genetic resources for C. gallina. We achieved the first transcriptome of this species with the aim of identifying an informative set of expressed genes, potential markers to assess genetic structure of natural populations and molecular resources for pathogenic contamination detection. METHODOLOGY/PRINCIPAL FINDINGS: The 454-pyrosequencing of a normalized cDNA library of a pool C. gallina adult individuals yielded 298,494 raw reads. Different steps of reads assembly and filtering produced 36,422 contigs of high quality, one half of which (18,196 were annotated by similarity. A total of 111 microsatellites and 20,377 putative SNPs were identified. A panel of 13 polymorphic transcript-linked microsatellites was developed and their variability assessed in 12 individuals. Remarkably, a scan to search for contamination sequences of infectious origin indicated the presence of several Vibrionales species reported to be among the most frequent clam pathogen's species. Results reported in this study were included in a dedicated database available at http://compgen.bio.unipd.it/chameleabase. CONCLUSIONS/SIGNIFICANCE: This study represents the first attempt to sequence and de novo annotate the transcriptome of the clam C. gallina. The availability of this transcriptome opens new perspectives in the study of biochemical and physiological role of gene products and their responses to large and small-scale environmental stress in C. gallina, with high throughput experiments such as custom microarray or targeted re-sequencing. Molecular markers, such as the already optimized EST

  17. Presence of enteric viruses, bioaccumulation and stability in Anomalocardia brasiliana clams (Gmelin, 1791).

    Science.gov (United States)

    Souza, Doris Sobral Marques; Dominot, Ana Ferreira Ávila; Moresco, Vanessa; Barardi, Célia Regina Monte

    2018-02-02

    Bivalve mollusks are filter feeders and may accumulate human pathogens in their tissues. Many studies demonstrated human diseases associated with bivalve consumption, especially oysters. Anomalocardia brasiliana clams are distributed along the Brazilian coastal area and are an exotic ingredient for some typical dishes in Brazil. Even though there are several reports describing the contamination of oysters and mussels with human pathogens, there is a lack of studies reporting contamination of A. brasiliana with human pathogens. An evaluation of natural microbiological contamination in A. brasiliana samples over a period of 18months (November 2014 to April 2016) showed that the bacteria indices were in accordance with Brazilian regulations (E. colitime period. NoV GI was the most adsorbed virus after 24h. HAV concentration was time, reaching its highest values after 24h (times (0, 1, 1.5, 3 and 5mins), viral infectivity was evaluated using ICC-et-RT-qPCR. The temperature inside the DT remained time and after 5min of cooking the HAdV reached a decay of 90% (1 log 10 ). The results showed a real warn to the consumers that can be exposed to infectious human viruses if they eat these clams improperly cooked. HAV was the most detected virus in these animals, which may lead to outbreaks. A. brasiliana exhibited distinct behavior in NoV GI bioaccumulation and persistence, pointing to the need for further studies about the cellular ligands used by these viruses to become attached to these clams. Copyright © 2017. Published by Elsevier B.V.

  18. Comparison of selenium bioaccumulation in the clams Corbicula fluminea and Potamocorbula amurensis: A bioenergetic modeling approach

    Science.gov (United States)

    Lee, B.-G.; Lee, J.-S.; Luoma, S.N.

    2006-01-01

    Selenium uptake from food (assimilation efficiency) and dissolved phase (influx rate) as well as loss kinetics (efflux rate) were compared between two bivalves, Corbicula fluminea and Potamocorbula amurensis. The effects of salinity and temperature on these kinetic parameters for both clam species also were evaluated. The Asiatic clam, C. fluminea, more efficiently assimilated Se associated with algae (66-87%) than Se associated with oxic sediments (20-37%). However, no consistent difference was found between Se assimilation efficiencies from both food types (19-60%) for P. amurensis. The temperature and salinity had a minor influence on the Se assimilation from ingested food. However, the effects of temperature and salinity were more evident in the uptake from dissolved sources. The influx rate of Se(IV) increased by threefold with the increase of temperature from 5 to 21??C for C. fluminea. The increase of salinity from 4 to 20 psu decreased the uptake rate constant (ku) of Se in P. amurensis from 0.011 to 0.005 L/g/h, whereas salinity change (0-8 psu) had a negligible effect on the Se influx rate of C. fluminea. The Se influx rate of P. amurensis decreased by half with the 3.5-fold increase in tissue dry weight. The rate constant of loss was greater for P. amurensis (0.029/d at 8 psu) than for C. fluminea (0.014/d at 0 psu and 0.01/d at 8 psu). A bioenergetic model suggests that dietary uptake is the dominant pathway for Se bioaccumulation in the two clams in San Francisco Bay and that interspecies differences in Se bioaccumulation can be explained by differences in food ingestion rates. ?? 2006 SETAC.

  19. Assessment of domestic landfill leachate toxicity to the Asian clam Corbicula fluminea via biomarkers.

    Science.gov (United States)

    Oliveira, Luciana F; Silva, Sandra M C P; Martinez, Claudia B R

    2014-05-01

    In order to evaluate the effects of domestic landfill leachate to bivalves Corbicula fluminea, clams were exposed to different leachate concentrations (v/v): 2, 3, 6 and 10 percent, corresponding to dilutions observed along a stream that receives this effluent, or only to clean water for comparisons. After 5 and 15 days of exposure the activity of the biotransformation enzymes 7-ethoxyresorufin-O-deethylase (EROD) and glutathione S-transferase (GST), the multixenobiotic resistance mechanism (MXR) and lipid peroxidation (LPO) in gills and digestive gland and metallothionein (MT) content in gills were evaluated. Differences in biomarkers responses were observed between gills and digestive gland, except for MXR that decreased in both tissues of clams exposed to 6 percent for 5 days. EROD activity in gills was reduced in all leachate concentrations after 5 days and only in 2 percent after 15 days exposure, while an EROD increase was observed in digestive gland after 15 days exposure to 6 percent. GST activity increased only in the gills of clams exposed to 10 percent for 5 days. LPO varied between tissues and different conditions. A significant increase in LPO was observed in the gills, after 5 days exposure to 2 and 6 percent, and in digestive gland after 5 and 15 days exposure to 2 and 3 percent. MT content in the gills increased after 15 days exposure to 2 percent. In conclusion, different leachate concentrations tested here caused biochemical changes in C. fluminea, but due to the observed variability in biomarkers responses among leachate concentrations, it was difficult to determine patterns or thresholds concentrations. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Impact of cadmium contamination and oxygenation levels on biochemical responses in the Asiatic clam Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Legeay, Alexia [Laboratoire d' Ecophysiologie et Ecotoxicologie des Systemes Aquatiques (LEESA), UMR 5805-OASU, Universite Bordeaux 1 and CNRS, Place Peyneau, 33120 Arcachon (France)]. E-mail: a.legeay@epoc.u-bordeaux1.fr; Achard-Joris, Maud [Laboratoire d' Ecophysiologie et Ecotoxicologie des Systemes Aquatiques (LEESA), UMR 5805-OASU, Universite Bordeaux 1 and CNRS, Place Peyneau, 33120 Arcachon (France); Baudrimont, Magalie [Laboratoire d' Ecophysiologie et Ecotoxicologie des Systemes Aquatiques (LEESA), UMR 5805-OASU, Universite Bordeaux 1 and CNRS, Place Peyneau, 33120 Arcachon (France); Massabuau, Jean-Charles [Laboratoire d' Ecophysiologie et Ecotoxicologie des Systemes Aquatiques (LEESA), UMR 5805-OASU, Universite Bordeaux 1 and CNRS, Place Peyneau, 33120 Arcachon (France); Bourdineaud, Jean-Paul [Laboratoire d' Ecophysiologie et Ecotoxicologie des Systemes Aquatiques (LEESA), UMR 5805-OASU, Universite Bordeaux 1 and CNRS, Place Peyneau, 33120 Arcachon (France)

    2005-09-10

    The aim of this work was to evaluate the potential utility of several biochemical parameters as indicators of the toxic effects of cadmium in the freshwater clam Corbicula fluminea under two levels of oxygenation (normoxia 21 kPa and hypoxia 4 kPa). These variations in oxygenation are representative of the natural environments of bivalves living at the bottom of the water column, where hypoxic episodes may occur regularly. Cadmium accumulation, metallothionein synthesis, MXR protein induction, lipoperoxidation and antioxidant enzyme activities (catalase, glutathione reductase and total and selenium-dependent glutathione peroxidases) were assessed in the gills of C. fluminea in four experimental conditions: normoxia, hypoxia, normoxia with cadmium and hypoxia with cadmium ([Cd] = 30 {mu}g l{sup -1}) over a 14-day period. Behavioural reactions were also followed for the duration of the experiment by monitoring clam activity and valve movements. This study is a first report on biochemical responses under cadmium contamination and hypoxia and will enable us to determine better biomarkers for C. fluminea as they were measured simultaneously. In metal-exposed animals, we found an increasing accumulation of cadmium in the gills with time, and this was more severe in hypoxic conditions. Metallothionein synthesis occurred in contaminated clams and was precocious in hypoxic conditions. MXR protein induction appeared promising due to its quick and significant response to metal with a strong impact from hypoxic contamination. On the other hand, in our experimental conditions, antioxidant parameters did not show decisive responses to contamination and hypoxia, except glutathione peroxidases which decreased systematically with time in a cadmium-independent manner. Lipid peroxidation, expressed as malondialdehyde content, was not stimulated by normoxic contamination, as has been shown in other studies, but was stimulated under hypoxic cadmium contamination. Our study confirms the

  1. Manila clams from Hg polluted sediments of Marano and Grado lagoons (Italy) harbor detoxifying Hg resistant bacteria in soft tissues

    International Nuclear Information System (INIS)

    Baldi, Franco; Gallo, Michele; Marchetto, Davide; Faleri, Claudia; Maida, Isabel; Fani, Renato

    2013-01-01

    A mechanism of mercury detoxification has been suggested by a previous study on Hg bioaccumulation in Manila clams (Ruditapes philippinarum) in the polluted Marano and Grado lagoons and in this study we demonstrate that this event could be partly related to the detoxifying activities of Hg-resistant bacteria (MRB) harbored in clam soft tissues. Therefore, natural clams were collected in six stations during two different periods (winter and spring) from Marano and Grado Lagoons. Siphons, gills and hepatopancreas from acclimatized clams were sterile dissected to isolate MRB. These anatomical parts were glass homogenized or used for whole, and they were lying on a solid medium containing 5 mg l −1 HgCl 2 and incubated at 30 °C. A total of fourteen bacterial strains were isolated and were identified by 16S rDNA sequencing and analysis, revealing that strains were representative of eight bacterial genera, four of which were Gram-positive (Enterococcus, Bacillus, Jeotgalicoccus and Staphylococcus) and other four were Gram-negative (Stenotrophomonas, Vibrio, Raoultella and Enterobacter). Plasmids and merA genes were found and their sequences determined. Fluorescence in situ hybridization (FISH) technique shows the presence of Firmicutes, Actinobacteria and Gammaproteobacteria by using different molecular probes in siphon and gills. Bacterial clumps inside clam flesh were observed and even a Gram-negative endosymbiont was disclosed by transmission electronic microscope inside clam cells. Bacteria harbored in cavities of soft tissue have mercury detoxifying activity. This feature was confirmed by the determination of mercuric reductase in glass-homogenized siphons and gills. -- Highlights: ► We isolated Gram-positive and Gram-negative Hg resistant strains from soft tissues of Ruditapes philippinarum. ► We identify 14 mercury resistant strains by 16S rRNA gene sequences. ► Bacteria in siphon and gill tissues of clams were observed by TEM and identified with

  2. Chromium accumulation in the Asian clam, Corbicula fluminea (Müller, 1774), as an indicative of landfill leachate contamination.

    Science.gov (United States)

    de Oliveira, Luciana Fernandes; Martinez, Claudia Bueno dos Reis

    2014-08-01

    The Asian clam Corbicula fluminea exposed in situ for periods of 1, 5, 15 and 30 days along a stream which receives landfill leachate effluent showed increased Cr accumulation in gills and digestive gland, although Cr concentrations have been found to be low in sediment. Other metals such as Pb, Ni, Al and Cu were also analyzed but were found to accumulate in clam tissues in lower concentrations or without showing a consistent pattern. Thus, the accumulation of a single contaminant such as Cr is proposed to be used as a tool to assess exposure to a complex mixture such as landfill leachates.

  3. Long-Term Surveys Show Invasive Overbite Clams (Potamocorbula amurensis) are Spatially Limited in Suisun Marsh, California

    OpenAIRE

    Baumsteiger, Jason; Schroeter, Robert E.; O'Rear, Teejay; Cook, Jonathan D.; Moyle, Peter B.

    2017-01-01

    https://doi.org/10.15447/sfews.2017v15iss2art6 The overbite clam (Potamocorbula amurensis) is a major invasive species in the San Francisco Estuary, California, and has been implicated in the decline of pelagic productivity and native fish species. Little is known of its impact on Suisun Marsh, a large brackish tidal region of the estuary. We looked at the abundance and spatial distribution of clams in the marsh, including examining the influence of water quality, using lon...

  4. Long-Term Surveys Show Invasive Overbite Clams (Potamocorbula amurensis) are Spatially Limited in Suisun Marsh, California

    OpenAIRE

    Jason Baumsteiger; Robert E. Schroeter; Teejay O'Rear; Jonathan D. Cook; Peter B. Moyle

    2017-01-01

    https://doi.org/10.15447/sfews.2017v15iss2art6The overbite clam (Potamocorbula amurensis) is a major invasive species in the San Francisco Estuary, California, and has been implicated in the decline of pelagic productivity and native fish species. Little is known of its impact on Suisun Marsh, a large brackish tidal region of the estuary. We looked at the abundance and spatial distribution of clams in the marsh, including examining the influence of water quality, using long-term (1988–2015) o...

  5. Manila clams from Hg polluted sediments of Marano and Grado lagoons (Italy) harbor detoxifying Hg resistant bacteria in soft tissues

    Energy Technology Data Exchange (ETDEWEB)

    Baldi, Franco, E-mail: baldi@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Cà Foscari University of Venice, Dorsoduro 2137, 30123 Venice (Italy); Gallo, Michele; Marchetto, Davide [Dipartimento di Scienze Molecolari e Nanosistemi, Cà Foscari University of Venice, Dorsoduro 2137, 30123 Venice (Italy); Faleri, Claudia [Department of Environmental Science ‘G. Sarfatti’, University of Siena, 53100 Siena (Italy); Maida, Isabel; Fani, Renato [Dipartimento di Biologia Evoluzionistica, Via Romana, 17, University of Florence, 50125 Florence (Italy)

    2013-08-15

    A mechanism of mercury detoxification has been suggested by a previous study on Hg bioaccumulation in Manila clams (Ruditapes philippinarum) in the polluted Marano and Grado lagoons and in this study we demonstrate that this event could be partly related to the detoxifying activities of Hg-resistant bacteria (MRB) harbored in clam soft tissues. Therefore, natural clams were collected in six stations during two different periods (winter and spring) from Marano and Grado Lagoons. Siphons, gills and hepatopancreas from acclimatized clams were sterile dissected to isolate MRB. These anatomical parts were glass homogenized or used for whole, and they were lying on a solid medium containing 5 mg l{sup −1} HgCl{sub 2} and incubated at 30 °C. A total of fourteen bacterial strains were isolated and were identified by 16S rDNA sequencing and analysis, revealing that strains were representative of eight bacterial genera, four of which were Gram-positive (Enterococcus, Bacillus, Jeotgalicoccus and Staphylococcus) and other four were Gram-negative (Stenotrophomonas, Vibrio, Raoultella and Enterobacter). Plasmids and merA genes were found and their sequences determined. Fluorescence in situ hybridization (FISH) technique shows the presence of Firmicutes, Actinobacteria and Gammaproteobacteria by using different molecular probes in siphon and gills. Bacterial clumps inside clam flesh were observed and even a Gram-negative endosymbiont was disclosed by transmission electronic microscope inside clam cells. Bacteria harbored in cavities of soft tissue have mercury detoxifying activity. This feature was confirmed by the determination of mercuric reductase in glass-homogenized siphons and gills. -- Highlights: ► We isolated Gram-positive and Gram-negative Hg resistant strains from soft tissues of Ruditapes philippinarum. ► We identify 14 mercury resistant strains by 16S rRNA gene sequences. ► Bacteria in siphon and gill tissues of clams were observed by TEM and identified

  6. Effects of burial by the disposal of dredged materials from the Columbia River on Pacific razor clams (Siliqua patula)

    Energy Technology Data Exchange (ETDEWEB)

    Vavrinec, John; Kohn, Nancy P.; Hall, Kathleen D.; Romano, Brett A.

    2007-05-07

    Annual maintenance of the Columbia River navigation channel requires the U.S. Army Corps of Engineers (Corps) to dredge sediment from the river and dispose of the sediment in coastal areas at the mouth of the Columbia River. Some of these disposal areas can be as shallow as 12 m deep in waters off the coastal beaches, and dredged material disposal activities have therefore raised concerns of impacts to local razor clam (Siliqua patula) populations that are prevalent in the area. The Corps’ Portland District requested that the Marine Sciences Laboratory of the U.S. Department of Energy’s Pacific Northwest National Laboratory conduct laboratory experiments to evaluate the potential impacts of burial by dredged material to razor clams during disposal. Prior modeling of disposal events indicates three stresses that could have an impact on benthic invertebrates: convective descent and bottom encounter (compression forces due to bottom impact), dynamic collapse and spreading (surge as material washes over the bottom), and mounding (burial by material). Because the razor clam is infaunal, the effects of the first two components should be minimal, because the clams should be protected by substrate that is not eroded in the event and by the clams’ rapid digging capabilities. The mound resulting from the disposal, however, would bury any clams remaining in the footprint under as much as 12 cm of new sediment according to modeling, and the clams’ reaction to such an event and to burial is not known. Although the literature suggests that razor clams may be negatively affected by siltation and therefore perhaps by dredging and disposal activity, as well, impacts of this type have not been demonstrated. The primary purpose of this study was to evaluate the potential impacts of dredge material disposal on adult subtidal razor clam populations at the mouth of the Columbia River. Using the parameters defined in a previous model, a laboratory study was created in which a

  7. In Vitro Interactions of Asian Freshwater Clam (Corbicula fluminea) Hemocytes and Cryptosporidium parvum Oocysts

    Science.gov (United States)

    Graczyk, T. K.; Fayer, R.; Cranfield, M. R.; Conn, D. B.

    1997-01-01

    Corbicula fluminea hemocytes phagocytosed infectious oocysts of Cryptosporidium parvum in vitro. After 15, 30, 60, 90, and 120 min of incubation, averages of 35.8, 58.0, 69.7, 77.7, and 81.6% of the oocysts were phagocytosed by 24.3, 70.0, 78.5, 87.3, and 93.0% of the hemocytes, respectively. A single clam can retain by phagocytosis an average of 1.84 x 10(sup6) oocysts per ml of hemolymph. C. fluminea bivalves can serve as biological indicators of contamination of wastewaters and agricultural drainages with Cryptosporidium. PMID:16535656

  8. ALAM/CLAM and some applications of computer algebra systems to problems in general relativity

    International Nuclear Information System (INIS)

    Russell-Clark, R.A.

    1973-01-01

    This paper is divided into three parts. Part A presents a historical survey of the development of the system, a brief description of its features and, finally, a critical assessment. ALAM and CLAM have been used in many problems in General Relativity; the vast majority of these belong to a set of standard calculations termed ''metric applications''. However, four large non-standard applications have been attempted successfully and these are described in Part B. CAMAL is the only other system which has been used extensively for work in relativity. CAMAL has played an important role in two research projects and details of these are given in Part C

  9. Expression of cyp1a protein in the freshwater clam Corbicula fluminea (Müller

    Directory of Open Access Journals (Sweden)

    Vranković Jelena

    2011-01-01

    Full Text Available We investigated the expression of CYP1A in the foot, gill and visceral mass of the freshwater clam Corbicula fluminea in relation to polychlorinated biphenyls (PCBs exposure. Different PCBs congeners were found in the foot and visceral mass, while the expression of CYP1A was observed only in the visceral mass. However the level of CYP1A expression in the visceral mass was not related to the level of PCBs present in the tissue. Our results indicate a higher rate of biotransformation and lower threshold of CYP1A induction in the visceral mass compared with other tissues.

  10. Overview on the welding technologies of CLAM steel and the DFLL TBM fabrication

    Directory of Open Access Journals (Sweden)

    Junyu Zhang

    2016-12-01

    Full Text Available Dual Functional Lithium Lead (DFLL blanket was proposed for its advantages of high energy exchange efficiency and on-line tritium extraction, and it was selected as the candidate test blanket module (TBM for China Fusion Engineering Test Reactor (CFETR and the blanket for Fusion Design Study (FDS series fusion reactors. Considering the influence of high energy fusion neutron irradiation and high heat flux thermal load on the blanket, China Low Activation Martensitic (CLAM steel was selected as the structural material for DFLL blanket. The structure of the blanket and the cooling internal components were pretty complicated. Meanwhile, high precision and reliability were required in the blanket fabrication. Therefore, several welding techniques, such as hot isostatic pressing diffusion bonding, tungsten inner gas welding, electron beam welding and laser beam welding were developed for the fabrication of cooling internals and the assembly of the blanket. In this work, the weldability on CLAM steel by different welding methods and the properties of as-welded and post-weld heat-treated joints were investigated. Meanwhile, the welding schemes and the assembly strategy for TBM fabrication were raised. Many tests and research efforts on scheme feasibility, process standardization, component qualification and blanket assembly were reviewed.

  11. Toxicity of ammonia to surf clam (Spisula solidissima) larvae in saltwater and sediment elutriates.

    Science.gov (United States)

    Ferretti, James A; Calesso, Diane F

    2011-04-01

    Ammonia is a natural component of sediments and has been identified as a common contributor to toxicity in marine sediment, elutriate and porewater testing. In our study, the role of ammonia as a possible toxicant in sediment toxicity tests was evaluated using larvae of the surf clam, Spisula solidissima. Elutriates were prepared and tested using six baseline sediment samples. Ammonia was then purged from aliquots of the baseline sediment samples prior to elutriate preparation. Finally, ammonia was spiked into aliquots of the purged elutriates to mimic ammonia concentrations measured in the baseline elutriates. Toxicity was present in all of the baseline samples and was removed in the ammonia purged samples. In most cases, toxicity was comparable in the ammonia spiked samples to levels measured in the baseline samples. Water only toxicity tests revealed that larvae of the surf clam are one of the more ammonia sensitive marine species. The LC50 for survival was 10.6 mg/L total ammonia (.53 mg/L unionized ammonia) and the EC50 for shell development was 2.35 mg/L total ammonia (.12 mg/L unionized ammonia). Toxicity endpoints calculated from the water only ammonia toxicity test were good predictors of effects observed in the sediment elutriate tests. Published by Elsevier Ltd.

  12. Genetic diversity of giant clams (Tridacna spp.) and their associated Symbiodinium in the central Red Sea

    KAUST Repository

    Pappas, Melissa

    2017-05-19

    The biodiversity of the Red Sea remains relatively understudied, particularly for invertebrate taxa. Documenting present patterns of biodiversity is essential for better understanding Red Sea reef ecosystems and how these ecosystems may be impacted by stressors (such as fishing and climate change). Several species of giant clams (genus Tridacna) are reported from the Red Sea, although the majority of research effort has occurred in the Gulf of Aqaba. We investigated the genetic diversity (16S rDNA) of the Tridacna species found in the central Saudi Arabian Red Sea. We also investigated the genetic diversity (ITS rDNA) of symbiotic dinoflagellates Symbiodinium associated with these clams. Samples were collected from nine reefs on a cross-shelf gradient near Thuwal, Saudi Arabia. Two species, T. squamosa and T. maxima, were recorded, with the latter being the most abundant. Tridacna squamosina, a species recently reported in the northern Red Sea, was not found, suggesting that this species is not present or is very rare in our study region. All tridacnids sampled were found to harbor Symbiodinium grouped in Clade A, considered an opportunistic, heat-tolerant symbiont group in anemones and corals. The consistent association with Clade A Symbiodinium in central Red Sea tridacnids may reflect the consequence of adaptation to the relatively extreme conditions of the Red Sea. This study contributes to an ever-growing catalog of Red Sea biodiversity and serves as important baseline information for a region experiencing dynamic pressures.

  13. Two new miniature inverted-repeat transposable elements in the genome of the clam Donax trunculus.

    Science.gov (United States)

    Šatović, Eva; Plohl, Miroslav

    2017-10-01

    Repetitive sequences are important components of eukaryotic genomes that drive their evolution. Among them are different types of mobile elements that share the ability to spread throughout the genome and form interspersed repeats. To broaden the generally scarce knowledge on bivalves at the genome level, in the clam Donax trunculus we described two new non-autonomous DNA transposons, miniature inverted-repeat transposable elements (MITEs), named DTC M1 and DTC M2. Like other MITEs, they are characterized by their small size, their A + T richness, and the presence of terminal inverted repeats (TIRs). DTC M1 and DTC M2 are 261 and 286 bp long, respectively, and in addition to TIRs, both of them contain a long imperfect palindrome sequence in their central parts. These elements are present in complete and truncated versions within the genome of the clam D. trunculus. The two new MITEs share only structural similarity, but lack any nucleotide sequence similarity to each other. In a search for related elements in databases, blast search revealed within the Crassostrea gigas genome a larger element sharing sequence similarity only to DTC M1 in its TIR sequences. The lack of sequence similarity with any previously published mobile elements indicates that DTC M1 and DTC M2 elements may be unique to D. trunculus.

  14. Distribution of platinum and other traffic related metals in sediments and clams (Corbicula sp.).

    Science.gov (United States)

    Ruchter, Nadine; Sures, Bernd

    2015-03-01

    Platinum is part of traffic-emitted metals since the introduction of automotive catalyst converters. Still, automobile emissions are one of the major sources for metals in European river systems. However, field data on Pt is scarce and there is a lack of knowledge concerning the distribution and biological availability of Pt. Therefore, the distribution of traffic related metals (Cd, Cr, Cu, Ni, Pb, Pt, and Zn) was analyzed in sediment samples and in the Asian clam Corbicula sp. Samples were taken from three transects following road runoff inlets. Pt was introduced into the river by road runoff. The highest Pt concentrations in sediments were analyzed in the silt/clay fraction (45 ng/g), while the highest total Pt burden was obtained for the sand fraction, that makes up more than 60% of the sediment. Metal concentrations were related to the area of the drained street section as well as to their distance from the discharge point, and to grain size distribution within the sediment. Pt and other traffic related metals were accumulated by clams. Due to the feeding behavior of the freshwater mussel Corbicula sp. Pt concentrations in the soft tissue remain relatively low (max Pt concentration: 1.3 ng/g freeze dried soft tissue) and acute lethal or toxic effects therefore appear to be unlikely. Nonetheless, chronic exposure effects still have to be examined. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Online detection of waterborne bioavailable copper by valve daily rhythms in freshwater clam Corbicula fluminea.

    Science.gov (United States)

    Jou, L J; Chen, W Y; Liao, C M

    2009-08-01

    Freshwater clam Corbicula fluminea, a surrogate species in metal toxicity testing, is a promising bioindicator of impairment in aquatic ecosystems. Little is known, however, about the relationship between clam valve daily rhythmic response and metal bioavailability related to a metal biological early warning system (BEWS) design. The purpose of this study was to link biotic ligand model (BLM)-based bioavailability and valve daily rhythm in C. fluminea to design a biomonitoring system for online in situ detection of waterborne copper (Cu). We integrated the Hill-based dose-time-response function and the fitted daily rhythm function of valve closure into a constructed programmatic mechanism. The functional presentation of the present dynamic system was completely demonstrated by employing a LabVIEW graphic control program in a personal computer. We used site-specific effect concentration causing 10% of total valve closure response (EC10) as the detection threshold to implement the proposed C. fluminea-based Cu BEWS. Here our results show that the proposed C. fluminea-based BEWS could be deliberately synthesized to online in situ transmit rapidly the information on waterborne bioavailable Cu levels under various aquatic environmental conditions through monitoring the valve daily rhythmic changes. We suggested that the developed C. fluminea-based dynamic biomonitoring system could assist in developing technically defensible site-specific water quality criteria to promote more efficient uses in water resources for protection of species health in aquatic environments.

  16. Development of molecular resources for an intertidal clam, Sinonovacula constricta, using 454 transcriptome sequencing.

    Directory of Open Access Journals (Sweden)

    Donghong Niu

    Full Text Available BACKGROUND: The razor clam Sinonovacula constricta is a benthic intertidal bivalve species with important commercial value. Despite its economic importance, knowledge of its transcriptome is scarce. Next generation sequencing technologies offer rapid and efficient tools for generating large numbers of sequences, which can be used to characterize the transcriptome, to develop effective molecular markers and to identify genes associated with growth, a key breeding trait. RESULTS: Total RNA was isolated from the mantle, gill, liver, siphon, gonad and muscular foot tissues. High-throughput deep sequencing of S. constricta using 454 pyrosequencing technology yielded 859,313 high-quality reads with an average read length of 489 bp. Clustering and assembly of these reads produced 16,323 contigs and 131,346 singletons with average lengths of 1,376 bp and 458 bp, respectively. Based on transcriptome sequencing, 14,615 sequences had significant matches with known genes encoding 147,669 predicted proteins. Subsequently, previously unknown growth-related genes were identified. A total of 13,563 microsatellites (SSRs and 13,634 high-confidence single nucleotide polymorphism loci (SNPs were discovered, of which almost half were validated. CONCLUSION: De novo sequencing of the razor clam S. constricta transcriptome on the 454 GS FLX platform generated a large number of ESTs. Candidate growth factors and a large number of SSRs and SNPs were identified. These results will impact genetic studies of S. constricta.

  17. Fishery of the short-necked clam Paphia undulata in Southern Negros Occidental, Central Philippines

    Directory of Open Access Journals (Sweden)

    Karen A. Villarta

    2010-06-01

    Full Text Available This study documents the fishery of the short-necked clam Paphia undulata in coastal waters of southern Negros Occidental. Catch and effort estimates were determined based on daily records of compressor divers gathered between February-July 2008 in Himamaylan City and July 2008-May 2009 in the town of Hinigaran. Fishing and marketing practices in both areas were also documented and population biology information noted.Compared to earlier conditions, present fishing patterns show a worsened stage of overexploitation primarily characterized by collection of predominantly small and immature (mostly <45 mm shell lengths sizes. Intensity/duration and location of fishing also varied due to both abundance and demand factors.The difference in sizes of clams and the varying fishing durations in each area suggest a non-uniform pattern of settlement resulting most likely from differential larval recruitment, the likely factors causing the local boom and bust fishery. The larger and long term extent of the effect of these factors can only be further investigated by parallel 2-3 year fishery-dependent and -independent surveys

  18. Clams sensitivity towards As and Hg: A comprehensive assessment of native and exotic species.

    Science.gov (United States)

    Velez, Cátia; Freitas, Rosa; Antunes, Sara C; Soares, Amadeu M V M; Figueira, Etelvina

    2016-03-01

    To assess the environmental impact of As and Hg, bioindicator organisms such as bivalves have been used. Nevertheless, few studies have assessed the impacts of As and Hg in Ruditapes decussatus and Ruditapes philippinarum, which are native and exotic species in Europe, respectively. The main goal of the present study was to assess elements' partitioning and detoxification strategies of R. decussatus and R. philippinarum. Both clams showed a higher capacity to bioconcentrate Hg (BCF 2.29-7.49), when compared to As (0.59-1.09). Furthermore, As accumulation in both species was similar in the soluble and insoluble fractions, while in both species the majority of Hg was found in the insoluble fraction. Clams exposed to As showed different detoxification strategies, since R. decussatus had higher ability to enhance antioxidant enzymes and metallothioneins in order to reduce toxicity, and R.philippinarum increased glutathione S-transferase Ω activity, that catalyzes monomethyl arsenate reduction, the rate-limiting reaction in arsenic biotransformation. When exposed to Hg, R. decussatus presented, higher synthesis of antioxidant enzymes and lower LPO, being able to better tolerate Hg than the exotic species R. philippinarum. Thus under relevant levels of As and Hg contamination our work evidenced the higher ability of R. decussatus to survive and inhabit coastal environments not heavily contaminated by Hg and As. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Evaluation of the Appearance of Nail Polish Following Daily Treatment of Ex Vivo Human Fingernails With Topical Solutions of Tavaborole or Efinaconazole.

    Science.gov (United States)

    Vlahovic, Tracey C; Coronado, Dina; Chanda, Sanjay; Merchant, Tejal; Zane, Lee T

    2016-01-01

    Patients with onychomycosis may mask infected nails with polish. Tavaborole topical solution, 5% is a boron-based, small-molecule pharmaceutical approved for the treatment of toenail onychomycosis caused by Trichophyton rubrum and Trichophyton mentagrophytes; efinaconazole topical solution, 10% is approved for the same indication. Nail polish appearance after application of tavaborole (dropper) or efinaconazole (brush); respective applicator appearance; presence of color transfer from respective applicators; and color transfer to remaining solutions after dosing of polished nails were evaluated. Twelve ex vivo human cadaver fingernails were cleaned, polished with two coats of L'Oréal® Nail Color, Devil Wears Red #420, and mounted on floral foam. Nails were treated with tavaborole or efinaconazole solutions once daily for 7 days. Dropper and brush applicators were applied to white watercolor paper immediately after dosing to evaluate color transfer from polished nails. On day 7, remaining solutions were transferred to clear glass vials to evaluate color transfer from applicators to solutions. Nails, applicators, and papers were photographed daily following application; remaining solutions were photographed after 7 days of dosing. Tavaborole-treated polished nails showed no polish discoloration, and tavaborole applicators did not change in appearance during treatment. No color transfer from polished nails was evident to applicator, paper, or remaining solution. Efinaconazole-treated polished nails showed substantial polish changes after the first day of treatment, with polish appearance and discoloration progressively worsening over 7 days of treatment. Color transfer from nails was evident to applicator, paper, and remaining solution. Daily dropper application of tavaborole to ex vivo polished nails did not alter polish appearance. Brush application of efinaconazole produced visible changes in polish appearance and color transfer to applicators, paper, and

  20. Biomarker responses and contamination levels in the clam Ruditapes philippinarum for biomonitoring the Lagoon of Venice (Italy).

    Science.gov (United States)

    Matozzo, Valerio; Binelli, Andrea; Parolini, Marco; Locatello, Lisa; Marin, Maria Gabriella

    2010-03-01

    A multibiomarker approach was used to assess effects of environmental contaminants in the clam Ruditapes philippinarum from the Lagoon of Venice. Bivalves were collected in 8 sites of the Lagoon (Campalto, Marghera, Palude del Monte, Valle di Brenta, Cà Roman, San Servolo, Fusina and Canale Dese), differently influenced by both anthropogenic impact and natural conditions. The following biomarkers were chosen: total haemocyte count and lysozyme activity in cell-free haemolymph as immunomarkers, acetylcholinesterase activity in gills as a biomarker of exposure to neurotoxic compounds, vitellogenin-like protein levels in both digestive gland and cell-free haemolymph as a biomarker of exposure to estrogenic compounds, and survival-in-air widely used to evaluate general stress conditions in clams. In addition, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), 1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) and its breakdown products (DDE, DDD), hexachlorobenzene (HCB) and hexachlorocyclohexane (HCH) were measured in clams. Results demonstrated that the integrated approach between biomarkers and chemical analyses in R. philippinarum is a useful tool in biomonitoring the Lagoon of Venice. The biomarker responses suggested quite similar contamination levels in the entire Lagoon, although the relative impact of differing classes of pollutants changed among sites according to potential sources, as chemical analyses demonstrated. Overall, among the sampling sites investigated, Palude del Monte can represent an environmental risk area, bearing in mind its peculiar use for clam culture.

  1. Induction of a multixenobiotic resistance protein (MXR) in the Asiatic clam Corbicula fluminea after heavy metals exposure

    Energy Technology Data Exchange (ETDEWEB)

    Achard, M.; Baudrimont, M.; Boudou, A.; Bourdineaud, J.P

    2004-05-12

    Multixenobiotic resistance mechanisms (MXR) related to the mammalian P-glycoprotein multidrug transporter protein (P-gp) are known to occur in several marine invertebrates. In the present work, we report on the induction of an MXR protein by various heavy metals in the gills of the freshwater clam Corbicula fluminea. The evaluation of the MXR protein level was assessed by Western blot using a specific monoclonal antibody raised against the human P-gp (C219). A field transplantation experiment, where clams were caged in a gradient relative to an industrial site, demonstrated a positive relationship between MXR levels and (a) metal pollution (Cd and Zn) in the environment and (b) metal bioaccumulation in the gills. To establish this correlative relationship, clams were exposed to different levels of cadmium (15-60 {mu}g l{sup -1}) for up to 15 days in a controlled laboratory experiment. MXR protein levels increased in time for all treatments (including the control). However, the highest levels of MXR protein titer were expressed in clams that had been exposed to the lowest dose of cadmium. The causes for this observed inverse relationship between the exposure dose and the MXR induction is discussed. MXR protein titer was also shown to be induced by other heavy metals (zinc, inorganic mercury, and copper)

  2. Sodium Gill Potential as a Tool to Monitor Valve Closure Behavior in Freshwater Clam Corbicula fluminea in Response to Copper

    Directory of Open Access Journals (Sweden)

    Wei-Yu Chen

    2008-09-01

    Full Text Available Valve closure behavior in freshwater clam Corbicula fluminea is a biologically sensitive endpoint. The purpose of this paper was to derive an electrophysiological response model of C. fluminea to assess copper (Cu-sodium (Na interactions in gill membrane, whereby valve closure behavior and Cu toxicity could be monitored. The proposed model was based on the integration of Cu bioavailability, Na and Cu internalizations, and electrochemically-based gill potentials. Based on Na active transport under non-equilibrium conditions, predicted gill potential of -8.2 mV agreed reasonably well with published the measured transepithelial potential of -7 mV in C. fluminea. Our proposed framework captured the general features observed in model applications including: (i 50% inhibitory Cu2+ activities for Na membrane potential (ENa and uptake rate (JNa were estimated to be 0.072 and 0.043 mM, respectively, with a stoichiometry of 3Cu2+: 1ENa and 1JNa; (ii the external Cu2+-dependent internal Na concentration could be parsimoniously estimated, and (iii the site-specific clam gill potentials could be monitored. Here we provided a new approach to monitor waterborne metal toxicity to reduce the nationwide economic losses due to bans on harvesting of contaminated clam and the potential risks to the health of clams.

  3. Sodium Gill Potential as a Tool to Monitor Valve Closure Behavior in Freshwater Clam Corbicula fluminea in Response to Copper

    Science.gov (United States)

    Liao, Chung-Min; Lin, Chieh-Ming; Jou, Li-John; Chen, Wei-Yu

    2008-01-01

    Valve closure behavior in freshwater clam Corbicula fluminea is a biologically sensitive endpoint. The purpose of this paper was to derive an electrophysiological response model of C. fluminea to assess copper (Cu)–sodium (Na) interactions in gill membrane, whereby valve closure behavior and Cu toxicity could be monitored. The proposed model was based on the integration of Cu bioavailability, Na and Cu internalizations, and electrochemically-based gill potentials. Based on Na active transport under non-equilibrium conditions, predicted gill potential of −8.2 mV agreed reasonably well with published the measured transepithelial potential of −7 mV in C. fluminea. Our proposed framework captured the general features observed in model applications including: (i) 50% inhibitory Cu2+ activities for Na membrane potential (ENa) and uptake rate (JNa) were estimated to be 0.072 and 0.043 μM, respectively, with a stoichiometry of 3Cu2+: 1ENa and 1JNa; (ii) the external Cu2+–dependent internal Na concentration could be parsimoniously estimated, and (iii) the site-specific clam gill potentials could be monitored. Here we provided a new approach to monitor waterborne metal toxicity to reduce the nationwide economic losses due to bans on harvesting of contaminated clam and the potential risks to the health of clams. PMID:27873813

  4. Selective pressurized liquid extraction technique capable of analyzing dioxins, furans, and PCBs in clams and crab tissue.

    Science.gov (United States)

    Subedi, Bikram; Aguilar, Lissette; Williams, E Spencer; Brooks, Bryan W; Usenko, Sascha

    2014-04-01

    A selective pressurized liquid extraction technique (SPLE) was developed for the analysis of polychlorodibenzo-p-dioxins, polychlorodibenzofurans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) in clam and crab tissue. The SPLE incorporated multiple cleanup adsorbents (alumina, florisil, silica gel, celite, and carbopack) within the extraction cell. Tissue extracts were analyzed by high resolution gas chromatography coupled with electron capture negative ionization mass spectrometry. Mean recovery (n = 3) and percent relative standard deviation for PCDD/Fs and dl-PCBs in clam and crabs was 89 ± 2.3 and 85 ± 4.0, respectively. The SPLE method was applied to clams and crabs collected from the San Jacinto River Waste Pits, a Superfund site in Houston, TX. The dl-PCBs concentrations in clams and crabs ranged from 50 to 2,450 and 5 to 800 ng/g ww, respectively. Sample preparation time and solvents were reduced by 92 % and 65 %, respectively, as compared to USEPA method 1613.

  5. A quantitative estimation of the energetic cost of brown ring disease in the Manila clam using Dynamic Energy Budget theory.

    NARCIS (Netherlands)

    Flye Sainte Marie, J.G.; Jean, F.; Paillard, C.; Kooijman, S.A.L.M.

    2009-01-01

    Brown ring disease (BRD) in the Manila clam, Ruditapes philippinarum, is a bacterial disease caused by the pathogen Vibrio tapetis. This disease induces the formation of a characteristic brown conchiolin deposit on the inner shell and is associated with a decrease in condition index indicating that

  6. Grazing impact of the invasive clam Corbula amurensis on the microplankton assemblage of the northern San Francisco Estuary

    Science.gov (United States)

    Greene, Valerie E.; Sullivan, Lindsay J.; Thompson, Janet K.; Kimmerer, Wim J.

    2011-01-01

    Grazing by the overbite clam Corbula amurensis (formerly known as Potamocorbula) may be the cause of substantial declines in phytoplankton biomass and zooplankton in the San Francisco Estuary (SFE) following its introduction in 1986. While grazing rates have been examined on bacteria, phytoplankton, and copepod nauplii, the consumption of protistan microzooplankton by C. amurensis has not previously been measured. In this study, laboratory feeding experiments revealed that C. amurensis cleared 0.5 l ind-1 h-1 of microzooplankton (ciliates) and 0.2 l ind-1 h-1 of chlorophyll (chl) a. Despite the higher clearance rate on microzooplankton, clams obtained more of their carbon from phytoplankton, which dominated the prey assemblage on most dates. When the measured clearance rates are extrapolated to field populations of clams, fractional loss rates (50 to 90% d-1) exceed the population growth capacity of microzooplankton. Although microzooplankton may not be a major component of the diet of these clams, C. amurensis may further alter food web dynamics through consumption of this important trophic intermediary, thus disrupting this link from bacteria and phytoplankton to higher trophic levels.

  7. Paleo-environments reconstructed from hermatypic coral skeleton and giant clam shell; Sango shakogai kokkaku ni yoru kokankyo no kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Nakamori, T. [Tohoku University, Sendai (Japan)

    1998-07-01

    For the elucidation of long-term climate changes in the Western Pacific tropical sea area on the basis of the outcome of studies for the reconstruction of paleo-environments using hermatypic corals, consideration is under way for exerting efforts for the tasks to be named below. The 8 degrees N line, corresponding to the northern border of the Western Pacific warm tongue, and the l40 degrees E line, longitudinally crossing the middle part of the said warm tongue, will be designated as the priority survey lines. Along these survey lines, Porites skeletons having bandings continuously covering 200-300 years and giant clam shells will be sampled. Weather data will be collected from meteorological observatories located in the vicinity of the locations of coral core specimens sampling. Data from AVHRR (advanced very high resolution radiometer) aboard NOAA (National Oceanic and Atmospheric Administration) satellites will be utilized. Secular changes in insolation will be revealed using thin flakes of big clam shells. Accuracy of seawater temperature estimation will be improved by use of coral and big clam shell for the establishment of salinity estimation algorithm. Hermatypic coral skeletons will be utilized to clarify variations in the Western Pacific warm tongue for the past 200-300 years. Fossils of coral and big clam shell will be used to reconstruct variations in oceanic environments due to climate changes in the Quaternary Period. 23 refs., 2 figs.

  8. Benthic metabolism over the emersion - immersion alternation in sands colonized by the invasive Manila clam Ruditapes philippinarum

    Science.gov (United States)

    Migné, Aline; Trigui, Rima Jihane; Davoult, Dominique; Desroy, Nicolas

    2018-01-01

    The effect of an invasive infaunal suspension-feeding bivalve, the Manila clam Ruditapes philippinarum, on benthic inorganic carbon and nutrient fluxes was examined through in situ incubations. Measurements were performed in spring and summer on a tidal sandflat of the Rance estuary (south part of the Western English Channel) colonized by the Manila clam after its deliberate introduction in the 1990's. Benthic inorganic carbon fluxes were measured using light and dark benthic chambers both at emersion and immersion. Benthic nutrient fluxes were measured using dark benthic chambers at immersion. Inorganic carbon (IC) and ammonium sediment release under darkness at immersion reached 5.60 mmol m-2 h-1 and 441 μmol m-2 h-1 respectively for a clam density of 291 ind m-2. The sediment IC-release under darkness was lower during emersion than during immersion, probably due to the reduced activity of infauna at low tide. Under ambient light, a sediment IC-uptake was systematically measured at emersion, indicating a net autotrophy under the condition of measurements (125 dark (i.e. community respiration), was similar at emersion and immersion and reached 6.2 mmolC m-2 h-1. These results suggest that the metabolic activity of the invasive Manila clam Ruditapes philippinarum contributes to increase inorganic C and ammonium sediment release. These regenerated nutrients may support microphytobenthic production which appeared particularly high on this intertidal sand flat.

  9. Effects of Fishing and Fishing Closures on Beach Clams: Experimental Evaluation across Commercially Fished and Non-Fished Beaches before and during Harvesting.

    Science.gov (United States)

    Gray, Charles A

    2016-01-01

    Management responses to reconcile declining fisheries typically include closed areas and times to fishing. This study evaluated this strategy for a beach clam fishery by testing the hypothesis that changes in the densities and size compositions of clams from before to during harvesting would differ between commercially fished and non-fished beaches. Sampling was spatially stratified across the swash and dry sand habitats on each of two commercially fished and two non-fished beaches, and temporally stratified across three six-week blocks: before, early and late harvesting. Small-scale spatio-temporal variability in the densities and sizes of clams was prevalent across both habitats and the components of variation were generally greatest at the lowest levels examined. Despite this, differences in the densities and sizes of clams among individual beaches were evident, but there were few significant differences across the commercially fished versus non-fished beaches from before to during harvesting. There was no evidence of reduced densities or truncated size compositions of clams on fished compared to non-fished beaches, contrasting reports of some other organisms in protected areas. This was probably due to a combination of factors, including the current levels of commercial harvests, the movements and other local-scale responses of clams to ecological processes acting independently across individual beaches. The results identify the difficulties in detecting fishing-related impacts against inherent levels of variability in clam populations. Nevertheless, continued experimental studies that test alternate management arrangements may help refine and determine the most suitable strategies for the sustainable harvesting of beach clams, ultimately enhancing the management of sandy beaches.

  10. Continuous low-level aquatic monitoring (CLAM) samplers for pesticide contaminant screening in urban runoff: Analytical approach and a field test case.

    Science.gov (United States)

    Ensminger, Michael P; Vasquez, Martice; Tsai, Hsing-Ju; Mohammed, Sarah; Van Scoy, A; Goodell, Korena; Cho, Gail; Goh, Kean S

    2017-10-01

    Monitoring of surface waters for organic contaminants is costly. Grab water sampling often results in non-detects for organic contaminants due to missing a pulse event or analytical instrumentation limitations with a small sample size. Continuous Low-Level Aquatic Monitoring (CLAM) samplers (C.I.Agent ® Solutions) continually extract and concentrate organic contaminants in surface water onto a solid phase extraction disk. Utilizing CLAM samplers, we developed a broad spectrum analytical screen for monitoring organic contaminants in urban runoff. An intermediate polarity solid phase, hydrophobic/lipophilic balance (HLB), was chosen as the sorbent for the CLAM to target a broad range of compounds. Eighteen urban-use pesticides and pesticide degradates were targeted for analysis by LC/MS/MS, with recoveries between 59 and 135% in laboratory studies. In field studies, CLAM samplers were deployed at discrete time points from February 2015 to March 2016. Half of the targeted chemicals were detected with reporting limits up to 90 times lower than routine 1-L grab samples with good precision between field replicates. In a final deployment, CLAM samplers were compared to 1-L water samples. In this side-by-side comparison, imidacloprid, fipronil, and three fipronil degradates were detected by the CLAM sampler but only imidacloprid and fipronil sulfone were detected in the water samples. However, concentrations of fipronil sulfone and imidacloprid were significantly lower with the CLAM and a transient spike of diuron was not detected. Although the CLAM sampler has limitations, it can be a powerful tool for development of more focused and informed monitoring efforts based on pre-identified targets in the field. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Investigation of coating CLAM steel substrates with erbium oxide by a magnetron sputtering method

    International Nuclear Information System (INIS)

    Liu Shuai; Ju Xin; Xin Yong; Qiu Jie; Li Tao; Cao Jiangli

    2010-01-01

    The study of tritium permeation barrier (TPB) coating is one of the most important subjects in the development of liquid lithium blankets in ITER and future fusion reactors. Erbium oxide ceramic is a promising candidate material for a TPB coating because of its high electrical resistance and high compatibility with liquid lithium. In this paper, an Er 2 O 3 coating was fabricated by using a magnetron sputtering method to deposit it on a China Low Activation Martensitic (CLAM) steel substrate. Er was performed as the buffer in order to improve the adhesive property of the Er 2 O 3 ceramic. The crystallinity of the coating was observed by X-ray diffraction (XRD) after annealing. A dominant orientation (4 4 0) presented with a thickness more than 1.5 μm. The structural properties, surface morphology and other physical properties of the coating were also studied.

  12. Comparative Study of the Accumulation of Ni in Different Tissues of Mussels and Soft Clams

    Directory of Open Access Journals (Sweden)

    Chalkiadakis O.

    2013-04-01

    Full Text Available Two bivalves, the mussel Mytilus galloprovincialis, and the soft clam Callista chione were exposed to various Ni concentrations for a total period of 20 days, and then a depuration period of 10 days followed. Nickel accumulation in gills, mantle and the remaining body of the animals was measured after 5, 10, 15 and 20 days of exposure to Ni-contaminated seawater. The two organisms showed different behavior regarding Ni accumulation in all three tissues examined. In all concentrations, Ni accumulation increased with time in all three tissues of Mytilus galloprovincialis with gills being the most effective accumulator per dry mass. On the other hand, Callista chione showed an initial response to Ni contamination the first 5 days, followed by stabilization or even a slight decrease of Ni accumulation.

  13. Use of antioxidant enzymes of clam Ruditapes philippinarum as biomarker to polycyclic aromatic hydrocarbon pollution

    Science.gov (United States)

    Zhu, Lin; Tang, Xuexi; Wang, Ying; Sui, Yadong; Xiao, Hui

    2016-03-01

    The typical organic pollutant polycyclic aromatic hydrocarbon (PAH) anthracene was selected as a contaminant to investigate its effects on the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in the clam Ruditapes philippinarum. The results show that SOD, CAT and GSH-Px had diff erent induction and inhibition reactions to anthracene stress, and that three diff erent organs in R. philippinarum (visceral mass, muscle tissue and mantle) had diff erent sensitivities to anthracene stress. This study suggest that SOD activities of the visceral mass, CAT activitities of the mantle and the visceral mass, and GSH-Px activity of the muscle tissue could be used as sensitive indicators of anthracene stress in R. philippinarum.

  14. Antioxidant and anti-tumor activity of a polysaccharide from freshwater clam, Corbicula fluminea.

    Science.gov (United States)

    Liao, Ningbo; Chen, Shiguo; Ye, Xingqian; Zhong, Jianjun; Wu, Nian; Dong, Shilei; Yang, Bo; Liu, Donghong

    2013-04-25

    The fresh water clam Corbicula fluminea is currently one of the most economically important aquatic species in China because of its nutritional value and pharmacological activity. In order to explore the potential of C. fluminea as a natural resource of bioactive compounds, a papain-released polysaccharide designated CFPS-2 was isolated. Chemical composition analysis indicated that CFPS-2 contained glucosamine, glucose, galactose, fucose, protein and sulfate groups, with an average molecular weight of about 22 kDa. Furthermore, the antioxidant and antitumor activities, in vitro, of the polysaccharide fractions (crude CFPS and purified CFPS-2) were evaluated. CFPS-2, which exhibited strong antioxidant activities in a dose dependent manner also showed significant inhibitory effects on growth of human gastric cancer cells (SGC7901) and human ovarian carcinoma cells (SKOV3 and A2780). The present results suggest that CFPS-2 could be a potential candidate for the development of novel functional food ingredient.

  15. POSSIBILITIES OF CULTIVATION OF CHAMELEA GALLINA (LINNAEUS, 1758 CLAM ALONG EASTERN ADRIATIC COAST

    Directory of Open Access Journals (Sweden)

    Iris Dupčić

    2004-09-01

    Full Text Available Chamelea gallina clam is among 16 shellfish species commonly present on Croatian fish markets. In the year 2000, European fishermen collected 39,819 tons of this species. The most abundant settlements of Chamelea gallina are situated along western Adriatic coast, however, there are settlements along eastern Adriatic coast especially in the estuaries of Neretva and Cetina, Nin and Novigradsko more areas, as well as along the coasts of islands; Brač, Rab and Susak. Ecological parameters affect growth rates, reproduction and mortality. Due to great temperature oscillations insufficient spat recruitment occurs on occasion. Temperature values determine the time and the intensity of spawning. Hatcheries insure constant and secure spat resource. Adults from brood stock mature during conditioning process, after which they are transferred into spawning tanks for fertilization. Brood stock, larvae, and spat are fed by cultured phytoplankton species.

  16. Parasites of the hard clam Meretrix meretrix Linnaeus from Western Johor Straits, Malaysian

    Science.gov (United States)

    Azmi, Nur Fauzana; Ghaffar, Mazlan Abd.; Cob, Zaidi Che

    2014-09-01

    This study describes the apicomplexa as well as other parasites infecting organs/tissues of the hard clam Meretrix meretrix Linnaeus, from Merambong Shoal, Western Johor Straits, Malaysia. Samples were collected randomly by hand picking, in November and December 2013. Histological techniques were performed, stained using Masson's Trichrome protocol and observed under light microscope. The results showed that gonad and gill were the most infected organs followed by digestive gland, intestine and adductor muscle. No pathology condition was observed in the mantle. Histophatological examination showed that the gregarine, Nematopsis, unidentified coccidian and Perkinsus were found in the gill and gonad, and also in the numerous hemocytes. Other pathological conditions such as bacteria-like inclusion and intracellular bacteria were also observed in the same organs. Further investigations are needed particularly on other molluscs present at the study area. Understanding the morphology and pathology of parasites infecting mollusks are very important for management of the resources.

  17. Purification and partial characterization of a heparin-binding lectin from the marine clam Anadara granosa.

    Science.gov (United States)

    Dam, T K; Bandyopadhyay, P; Sarkar, M; Ghosal, J; Bhattacharya, A; Choudhury, A

    1994-08-30

    The heparin-binding lectin, Anadarin MS, from the plasma of the marine clam Anadara granosa is purified through affinity chromatography on heparin-Sepharose 4B followed by gel filtration on a Sepharose 6B column. The purified lectin is a pentameric protein of native M(r) 300 kDa and is composed of identical subunits of 60 kDa. The pI value of this Ca(2+)-dependent lectin is 6.2. Anadarin MS agglutinates normal rabbit erythrocytes but not that of human. Aspartic acid, glutamic acid, histidine and glycine are the predominant amino acids. Unlike other reported heparin-binding lectins, Anadarin MS exhibits a unique and strict specificity for iduronic acid containing glycosaminoglycans. This lectin agglutinates infective promastigotes of Leishmania donovani exclusively and can therefore be used as a novel biochemical surface marker for this parasite.

  18. Combined proteomic and metallomic analyses in Scrobicularia plana clams to assess environmental pollution of estuarine ecosystems.

    Science.gov (United States)

    González-Domínguez, Raúl; Santos, Hugo Miguel; Bebianno, Maria João; García-Barrera, Tamara; Gómez-Ariza, José Luis; Capelo, José Luis

    2016-12-15

    Estuaries are very important ecosystems with great ecological and economic value, but usually highly impacted by anthropogenic pressure. Thus, the assessment of pollution levels in these habitats is critical in order to evaluate their environmental quality. In this work, we combined complementary metallomic and proteomic approaches with the aim to monitor the effects of environmental pollution on Scrobicularia plana clams captured in three estuarine systems from the south coast of Portugal; Arade estuary, Ria Formosa and Guadiana estuary. Multi-elemental profiling of digestive glands was carried out to evaluate the differential pollution levels in the three study areas. Then, proteomic analysis by means of two-dimensional gel electrophoresis and mass spectrometry revealed twenty-one differential proteins, which could be associated with multiple toxicological mechanisms induced in environmentally stressed organisms. Accordingly, it could be concluded that the combination of different omic approaches presents a great potential in environmental research. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Metal-solid interactions controlling the bioavailability of mercury from sediments to clams and sipunculans.

    Science.gov (United States)

    Zhong, Huan; Wang, Wen-Xiong

    2006-06-15

    The bioavailability of sedimentary Hg(II) and methylmercury (MeHg) was quantified by measuring the assimilation efficiency (AE) in the clam Ruditapes philippinarum and the extraction of the gut juices from the sipunculan Sipunculus nudus. Three factors (Hg concentration in sediment, Hg sediment contact time, and organic content of sediments) were modified to examine metal-solid interactions in controlling Hg bioavailability. The Hg AEs in the clams were strongly correlated with the extraction from the sipunculan gut juices for both Hg species. The bioavailability of both Hg(II) and MeHg generally increased with increased sediment Hg concentration but decreased with sedimentmetal contact time and increasing organic content (except that MeHg was not influenced by organic content). Hg(II) speciation in sediments, quantified by sequential chemical extraction (SCE), was dependent on geochemical conditions and greatly controlled the mobility and bioavailability of Hg(II) in sediments. Most bioavailable Hg(II) originated from the strongly complexed phase (e.g., Hg bound up in Fe/Mn oxide, amorphous organosulfur, or mineral lattice), whereas Hg bound with the organocomplexed phase (Hg humic and Hg2Cl2) was not bioavailable. Hg bound with the other geochemical phases (water soluble, HgO, HgSO4, and HgS) contributed very little to the bioavailable Hg due to their low partitionings. Further, the amount of bioavailable Hg was inversely related to the particle reactivity of Hg with the sediments. Detailed analyses of metal-solid interactions provide a better understanding of how Hg in sediments can predict Hg concentration and therefore bioavailability in benthic invertebrates.

  20. Impaired regulation of divalent cations with acute copper exposure in the marine clam Mesodesma mactroides.

    Science.gov (United States)

    Jorge, Marianna Basso; Lauer, Mariana Machado; Martins, Camila De Martinez Gaspar; Bianchini, Adalto

    2016-01-01

    The mechanism of copper (Cu) toxicity in marine invertebrates remains unclear. Therefore, marine clams (Mesodesma mactroides) were exposed (96h) to a concentration of dissolved Cu (1.6μmolL(-1)) inducing 10% mortality in sea water (30ppt). After in vivo exposure, tissue Cu accumulation (hemolymph, gill and digestive gland); hemolymph ionic (Na(+), K(+), Mg(2+) and Ca(2+)) and osmotic concentrations; tissue (gill and digestive gland) ionic concentration, enzyme (Na(+),K(+)-ATPase and carbonic anhydrase) activity, and oxygen consumption; and whole-body oxygen consumption were analyzed. Succinate dehydrogenase activity was evaluated in mitochondria isolated from gills and digestive gland and exposed (1h) in vitro to different concentrations of dissolved Cu (0.8, 7.7 and 78.7μmolL(-1)). In vivo exposure induced Cu accumulation in hemolymph, gills and digestive gland; increased Mg(2+) and decreased Ca(2+) concentration in hemolymph; decreased Mg(2+) concentration, increased Na(+),K(+)-ATPase activity and reduced carbonic anhydrase activity in gills; decreased Mg(2+) concentration, increased Ca(2+) concentration and increased Na(+),K(+)-ATPase activity in digestive gland; and reduced gill, digestive gland and whole-body oxygen consumption. Succinate dehydrogenase activity was inhibited after in vitro exposure to 78.7μmolL(-1) Cu. These findings indicate that Cu is an ionoregulatory toxicant in the marine clam M. mactroides. However, toxicity is related to disturbances in regulation of divalent cations (Mg(2+) and Ca(2+)) without effect on regulation of major monovalent cations (Na(+) and K(+)), as opposed to that observed in osmoregulating invertebrates exposed to Cu. However, other mechanism(s) of toxicity cannot be ruled out. Future studies must be performed to evaluate the consequence of the Cu-induced respiratory disturbances observed in M. mactroides. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. The Manila clam population in Arcachon Bay (SW France): Can it be kept sustainable?

    Science.gov (United States)

    Dang, Cécile; de Montaudouin, Xavier; Gam, Mériame; Paroissin, Christian; Bru, Noëlle; Caill-Milly, Nathalie

    2010-02-01

    The venerid clam Ruditapes philippinarum is the most prominent suspension-feeding bivalve inhabiting muddy intertidal seagrass beds in Arcachon Bay (SW France). It is exploited by fishermen, and Arcachon Bay ranks number one in France in terms of production and total biomass of this species. Previous studies revealed a decrease in the standing stock of R. philippinarum since 2003 and unbalanced length-frequency distributions with a lack of juveniles and of adults > 40 mm. Consequently, the population dynamics of this bivalve were studied at four intertidal sites and one oceanic site in Arcachon Bay. As clam size structure did not allow classical dynamics computations, field monitoring was coupled with field experiments (tagging-recapture) over two years. Monitoring of condition index and gonadal maturation stages highlighted a high variability in spawning number and intensity between sites. Recruitment events in the exploited area varied spatially but with uniformly low values. Von Bertalanffy Growth Function (VBGF) parameters ( K, L∞) were determined using Appeldoorn and ELEFAN methods. In the exploited sites in the inner lagoon, K was relatively high (mean = 0.72 yr - 1 ) but L∞ was low (mean = 41.1 mm) resulting in a moderate growth performance index (Φ' = 2.99). Growth parameters were not correlated with immersion time and L∞ was different between sites. Comparison of mortality coefficients ( Z) between cage experiments and field monitoring suggested that fishing accounts for 65-75% of total adult mortality. Low recruitment, a low growth rate and a normal mortality rate led to low somatic production (4.1 and 8.7 g Shell-Free Dry Weight (SFDW) m - 2 yr - 1 ) and an annual P/ B ratio from 0.44 to 0.92 yr - 1 . Under current conditions, the possibility of a sustainable population in Arcachon Bay will strongly depend on recruitment success and fishing management.

  2. Recruitment constraints in Singapore's fluted giant clam (Tridacna squamosa population--a dispersal model approach.

    Directory of Open Access Journals (Sweden)

    Mei Lin Neo

    Full Text Available Recruitment constraints on Singapore's dwindling fluted giant clam, Tridacna squamosa, population were studied by modelling fertilisation, larval transport, and settlement using real-time hydrodynamic forcing combined with knowledge of spawning characteristics, larval development, behaviour, and settlement cues. Larval transport was simulated using a finite-volume advection-diffusion model coupled to a three-dimensional hydrodynamic model. Three recruitment constraint hypotheses were tested: 1 there is limited connectivity between Singapore's reefs and other reefs in the region, 2 there is limited exchange within Singapore's Southern Islands, and 3 there exist low-density constraints to fertilisation efficacy (component Allee effects. Results showed that connectivity among giant clam populations was primarily determined by residual hydrodynamic flows and spawning time, with greatest chances of successful settlement occurring when spawning and subsequent larval dispersal coincided with the period of lowest residual flow. Simulations suggested poor larval transport from reefs located along the Peninsular Malaysia to Singapore, probably due to strong surface currents between the Andaman Sea and South China Sea combined with a major land barrier disrupting larval movement among reefs. The model, however, predicted offshore coral reefs to the southeast of Singapore (Bintan and Batam may represent a significant source of larvae. Larval exchange within Singapore's Southern Islands varied substantially depending on the locations of source and sink reefs as well as spawning time; but all simulations resulted in low settler densities (2.1-68.6 settled individuals per 10,000 m(2. Poor fertilisation rates predicted by the model indicate that the low density and scattered distribution of the remaining T. squamosa in Singapore are likely to significantly inhibit any natural recovery of local stocks.

  3. Influence of the invasive Asian clam Corbicula fluminea (Bivalvia: Corbiculidae) on estuarine epibenthic assemblages

    Science.gov (United States)

    Ilarri, M. I.; Souza, A. T.; Antunes, C.; Guilhermino, L.; Sousa, R.

    2014-04-01

    One of the most widespread invasive alien species (IAS) in aquatic ecosystems is the Asian clam Corbicula fluminea. Several studies have shown that C. fluminea can cause large-scale changes in macrozoobenthic assemblages; however, very few attempted to investigate the effects of this IAS on mobile epibenthic species, such as fishes and crustaceans. In this context, the influence of C. fluminea on epibenthic species was investigated during one year by comparing the associated epibenthic fauna in three nearby sites of the Minho estuary (NW of the Iberian Peninsula), wherein the abiotic conditions are similar but the density of the Asian clam is highly different. From a total of 13 species, six were significantly influenced by C. fluminea; five responded positively, namely the brown shrimp Crangon crangon, the European eel Anguilla anguilla, the common goby Pomatoschistus microps, the brown trout Salmo trutta fario and the great pipefish Syngnathus acus, whereas the shore crab Carcinus maenas was negatively influenced. However, stomach contents analysis revealed that fish and crustacean species do not feed on C. fluminea, suggesting that this IAS is still not a large component of the diet of higher trophic levels in this estuarine ecosystem. Our results suggest that the structure provided by C. fluminea shells is likely to be one of the main factors responsible for the differences observed. C. fluminea physical structure seems to influence the epibenthic associated fauna, when found in densities higher than 1000 ind./m2, with sedentary small-bodied crustaceans and fishes being mainly attracted by the increasing in habitat complexity and consequent enhancement of heterogeneity and shelter availability.

  4. Effects of elevated carbon dioxide concentrations on survivorship in zebra mussels (Dreissena polymorpha) and Asian clams (Corbicula fluminea)

    Energy Technology Data Exchange (ETDEWEB)

    McMahon, R.F.; Matthews, M.A.; Shaffer, L.R.; Johnson, P.D. [Univ. of Texas, Arlington, TX (United States)

    1995-06-01

    In order to determine their tolerance to elevated concentrations of carbon dioxide, Asian clams and zebra mussels were collected. Subsamples of both species were acclimated to 25{degrees}C>14 days and then exposed in water at 25{degrees}C to various concentrations of CO{sub 2} and survivorship recorded. Zebra mussels were allowed to byssally attach prior to testing. Media CO{sub 2} concentrations were maintained by continuous bubbling with appropriate gas mixtures. Gas treatment included: (1) anoxia; (2) hypercapnic anoxia; and (3) hypercapnic normoxia. Deaths were recorded in subsamples of both species every 12-24 h until 100% mortality was achieved. No significant mortality occurred among specimens of either species in air bubbled control media in any experiment. Mortality time of zebra mussels exposed to anoxia under 100% N{sub 2} was 103.7 h and of Asian clams, 349.7 h. Mortality was more rapid among samples of both species exposed to anoxia under 100% CO{sub 2}, mean time to death being 43.6 h for zebra mussels and 46.3 h for Asian clams. There was no difference in the survivorship of samples of either species under atmospheres of either 5% CO{sub 2} and 95% N{sub 2} or 100% N{sub 2}, however, Asian clams survived anoxia under either atmosphere 4 to 5 times longer than did zebra mussels. There was no significant mortality among Asian clam or zebra mussel samples after a 39 day exposure to hypercapnic normoxia. While exposure to hypercapnic normoxia under an atmosphere of 5% CO{sub 2}:19% O{sub 2}:76% N{sub 2} did not induce mortality in zebra mussel samples, it completely suppressed all byssal thread production after 7 days of exposure and induced all sampled individuals to release from their byssal attachments within 10 days of exposure. These results indicate that CO{sub 2} injection may be an easily applied, cost-effective, environmentally acceptable molluscicide for mitigation and control of raw water system macrofouling by Asian clams and zebra mussels.

  5. Morphological and functional characterization of hemocytes from two deep-sea vesicomyid clams Phreagena okutanii and Abyssogena phaseoliformis.

    Science.gov (United States)

    Tame, Akihiro; Ozawa, Genki; Maruyama, Tadashi; Yoshida, Takao

    2018-03-01

    Deep-sea vesicomyid clams harboring intracellular symbiotic sulfur-oxidizing bacteria are often dominant in chemosynthetic animal communities. Although they are known to have erythrocytes, little is known about other hemocytes. To investigate the types and roles of various hemocytes in vesicomyid clams, we performed morphological, histochemical and functional characterization of the hemocytes in two species, Phreagena okutanii, collected from 873 to 978 m depth, and Abyssogena phaseoliformis, from 5199 to 5355 m. Both were found to have three types of hemocytes: erythrocytes (ERCs), eosinophilic granulocytes (EGs), and basophilic granulocytes (BGs). The ERCs contain hemoglobin in the cytoplasm, with basophilic vacuoles containing acid polysaccharide, neutral lipids, and peroxidase. The EGs were found to contain acid polysaccharides and eosinophilic granules containing lysosomal enzymes, acid and alkaline phosphatases, chloroacetate esterase, and peroxidase. Although BGs had some basophilic granules with alkaline phosphatase, they lacked acid phosphatase and acid polysaccharides. The EGs and BGs were shown to have phagocytic ability, while the ERCs exhibited no phagocytosis. The EGs showed higher phagocytic activity as well as a higher phagosome-lysosome fusion rate than BGs. The hemocytes of the two vesicomyid species differed in the intracellular structures. In A. phaseoliformis, ERCs additionally contained neutral polysaccharides in vacuoles and had vesicles with acinus-like acidic mucus in the cytoplasm, neither of which were observed in P. okutanii. The eosinophilic granules in the EGs had heteromorphically-elongated shapes containing homogeneously electron-dense material in P. okutanii, but were more spherical and composed of fibrous structures in A. phaseoliformis. The difference in hemocytes between the two clams seems to be reflective of phylogenetically differentiated lineages adapting to differing conditions in their respective deep-sea environments

  6. Systems-level modeling the effects of arsenic exposure with sequential pulsed and fluctuating patterns for tilapia and freshwater clam

    International Nuclear Information System (INIS)

    Chen, W.-Y.; Tsai, J.-W.; Ju, Y.-R.; Liao, C.-M.

    2010-01-01

    The purpose of this paper was to use quantitative systems-level approach employing biotic ligand model based threshold damage model to examine physiological responses of tilapia and freshwater clam to sequential pulsed and fluctuating arsenic concentrations. We tested present model and triggering mechanisms by carrying out a series of modeling experiments where we used periodic pulses and sine-wave as featured exposures. Our results indicate that changes in the dominant frequencies and pulse timing can shift the safe rate distributions for tilapia, but not for that of freshwater clam. We found that tilapia increase bioenergetic costs to maintain the acclimation during pulsed and sine-wave exposures. Our ability to predict the consequences of physiological variation under time-varying exposure patterns has also implications for optimizing species growing, cultivation strategies, and risk assessment in realistic situations. - Systems-level modeling the pulsed and fluctuating arsenic exposures.

  7. Systems-level modeling the effects of arsenic exposure with sequential pulsed and fluctuating patterns for tilapia and freshwater clam

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.-Y. [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Tsai, J.-W. [Institute of Ecology and Evolutionary Ecology, China Medical University, Taichung 40402, Taiwan (China); Ju, Y.-R. [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Liao, C.-M., E-mail: cmliao@ntu.edu.t [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2010-05-15

    The purpose of this paper was to use quantitative systems-level approach employing biotic ligand model based threshold damage model to examine physiological responses of tilapia and freshwater clam to sequential pulsed and fluctuating arsenic concentrations. We tested present model and triggering mechanisms by carrying out a series of modeling experiments where we used periodic pulses and sine-wave as featured exposures. Our results indicate that changes in the dominant frequencies and pulse timing can shift the safe rate distributions for tilapia, but not for that of freshwater clam. We found that tilapia increase bioenergetic costs to maintain the acclimation during pulsed and sine-wave exposures. Our ability to predict the consequences of physiological variation under time-varying exposure patterns has also implications for optimizing species growing, cultivation strategies, and risk assessment in realistic situations. - Systems-level modeling the pulsed and fluctuating arsenic exposures.

  8. Combined Effects of Temperature and Seston Concentration on the Physiological Energetics of the Manila Clam Ruditapes philippinarum.

    Directory of Open Access Journals (Sweden)

    Hee Yoon Kang

    Full Text Available The suspension-feeding Manila clam Ruditapes philippinarum is a native species of the western Pacific that is now widely distributed around the globe because of its commercial importance. To determine the adaptive physiological responses to changing thermal and nutritional conditions, clearance, filtration, feces production, ammonium excretion, respiration rates, and scope for growth (SFG were measured in adult clams. The clams were exposed to 24 treatments involving the combination of four water temperatures (8, 13, 18, and 23°C and six concentrations of suspended particulate matter (SPM: 9.5 to 350.5 mg L(-1. Physiological rates were standardized by using the mean (480 mg of tissue dry weights of experimental clams using allometric equations between physiological variables and tissue dry weight. Higher clearance rates were recorded at higher temperatures and lower SPM concentrations, and these rates decreased with increasing SPM concentration at individual temperatures. Consumed energy increased with increasing temperature and SPM concentration, peaking at around 100-200 mg L(-1 at 18-23°C. Whereas fecal energy was largely determined by SPM concentration, ammonia excretion was mainly governed by temperature. Respiration rate studies revealed a predominant quadratic effect of temperature on the metabolism, indicating a lack of acclimatory adjustment of metabolic rate to rising temperature. SFG values were positive under almost all the treatment conditions and were much higher at higher SPM concentrations (> 45 mg L(-1, with the highest level being recorded at 18°C and 100-200 mg L(-1 SPM. Increased filtration rate offset the increased metabolic cost at warm temperatures. Our holistic findings suggest that a high degree of physiological plasticity allows R. philippinarum to tolerate the wide range of temperatures and SPM concentrations that are found in tidal flats, accounting in part for the successful distribution of this species over a

  9. Identification of larvae: The zebra mussel (Dreissena polymorpha), quagga mussel (Dreissena rosteriformis bugensis), and Asian clam (Corbicula fluminea)

    Science.gov (United States)

    Nichols, S. Jerrine; Black, M.G.

    1994-01-01

    There are presently four freshwater bivalves in the United States that produce larvae or veligers commonly found in the water column: two forms of Asian clams and two species of dreissenids. Portions of the geographic range of three of these bivalves, one species of Asian clam (Corbicula fluminea), zebra mussels (Dreissena polymorpha), and quagga mussels (Dreissena rosteriformis bugensis), overlap, causing problems with larval identification. To determine which characteristics can be used to separate larval forms, adult Asian clams, quaggas, and zebra mussels were brought into the laboratory and induced to spawn, and the resulting larvae were reared. Hybrids between quaggas and zebra mussels were also produced, but not reared to maturity. Characteristics allowing for the most rapid and accurate separation of larvae were hinge length, shell length/height, shell shape, shell size, and the presence or absence of a foot and velum. These characteristics were observed in laboratory-reared larvae of known parentage and field-caught larvae of unknown parentage. In most cases, larvae of the Asian clam can be readily separated from those produced by either type of dreissenid on the basis of shell size and presence of a foot. Separating the gametes and embryos of the two types of dreissenids is not possible, but after shell formation, most of the larval stages can be distinguished. Hinge length, shell length/height, and the similarity in size of the shell valves can be used to separate straight-hinged, umbonal, pediveliger, and plantigrade larvae. Quagga × zebra mussel hybrids show characteristics of both parents and are difficult to identify.

  10. Shell shape analysis and spatial allometry patterns of Manila Clam (Ruditapes philippinarium) in a mesotidal coastal lagoon

    OpenAIRE

    Caill-Milly, Nathalie; Bru, Noëlle; Mahé, Kélig; D'Amico, Franck

    2012-01-01

    While gradual allometric changes of shells are intrinsically driven by genotype, morphometrical shifts can also be modulated by local environmental conditions. Consequently the common use of a unique dimension (usually length) to assess bivalves’ growth may mask phenotypic differences in valve shape among populations. A morphometric exhaustive study was conducted on Manila clam, Ruditapes philippinarum, by acquiring data in the French Arcachon Bay (intrasite phenotypic variability) and by com...

  11. Predicting acute copper toxicity to valve closure behavior in the freshwater clam Corbicula fluminea supports the biotic ligand model.

    Science.gov (United States)

    Liao, Chung-Min; Jou, Li-John; Lin, Chieh-Ming; Chiang, Kuo-Chin; Yeh, Ching-Hung; Chou, Berry Yun-Hua

    2007-06-01

    The objective of this paper is to employ biotic ligand model (BLM) to link between acute copper (Cu) toxicity and its effect on valve closure behavior of freshwater clam Corbicula fluminea in order to further support for the BLM that potentially offers a rapid and cost-effective method to conduct the acute toxicity tests for freshwater clam exposed to waterborne Cu. Reanalysis of published experimental data of C. fluminea closure daily rhythm and dose-response profiles based on the laboratory-acclimated clams showed that a BLM-based Hill model best described the free Cu(2+)-activity-valve closure response relationships. Our proposed Cu-BLM-Corbicula model shows that free ionic form of waterborne Cu binds specifically to a biotic ligand (i.e., clam gills) and impairs normal valve closure behavior, indicating that a fixed-level of metal accumulation at a biotic ligand is required to elicit specific biological effects. With derived mechanistic-based Cu-BLM-Corbicula model, we show that the site-specific EC50(t) and valve closure behavior at any integrated time can be well predicted, indicating that our model has the potential to develop a biomonitoring system as a bioassay tool to on-line measure waterborne Cu levels in aquatic systems. Our results confirm that BLM can be improved to analytically and rigorously describe the bioavailable fraction of metal causing toxicity to valve closure behavior in freshwater C. fluminea. We suggest that the Cu-BLM-Corbicula model can be used to assist in developing technically defensible site-specific water quality criteria and performing ecological risk assessment and to promote more focused and efficient uses of resources in the regulation and control of metals and the protection of the aquatic ecosystems.

  12. Size-dependent effects of low level cadmium and zinc exposure on the metabolome of the Asian clam, Corbicula fluminea.

    Science.gov (United States)

    Spann, Nicole; Aldridge, David C; Griffin, Julian L; Jones, Oliver A H

    2011-10-01

    The toxic effects of low level metal contamination in sediments are currently poorly understood. We exposed different sized Asian clams, Corbicula fluminea, to sediment spiked with environmentally relevant concentrations of either zinc, cadmium or a zinc-cadmium mixture for one week. This freshwater bivalve is well suited for sediment toxicity tests as it lives partly buried in the sediment and utilises sediment particles as a food resource. After one week, the whole tissue composition of low molecular weight metabolites was analysed by nuclear magnetic resonance spectroscopy (NMR) and gas chromatography-mass spectrometry (GC-MS). The condition index (ratio of tissue dry weight to volume inside the shell valves) was also measured. Small and large clams were clearly differentiated by their metabolic composition and the two size classes showed opposite responses to the mixture spiked sediment. No effects of zinc alone on the metabolome were found and cadmium only influenced the smaller size class. The main perturbations were seen in amino acid and energy metabolism, with small clams using amino acids as an energy resource and larger clams primarily drawing on their larger storage reserves of carbohydrates. Our study demonstrates that metabolomics is a useful technique to test for low level toxicity which does not manifest in mortality or condition index changes. The differing effects between the two size classes stress that it is important to consider age/size when conducting metabolomic and ecotoxicology assessments, since testing for the effects on only one size class makes it more difficult to extrapolate laboratory results to the natural environment. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). HARD CLAM.

    Science.gov (United States)

    1985-02-01

    sediment. The rock iated and secrete mucus . Particles crab, blue crab (Callinectes sapus), brought in through the incurrent and green crab (Carcinides...maenas) dig siphon attach to the mucus . Deposits up the clams, whereas mud crabs bury on the gills are collected by the themselves in the sediment to...caudata) and materials are collected on the mantle the moon snails 7Polinices duplicata and carried to the base of the siphon, and Lunatia heros

  14. Assessment of wet weather impact on clam (Chamelea gallina faecal contamination in the district of San Benedetto del Tronto (Italy

    Directory of Open Access Journals (Sweden)

    Piero Capocasa

    2013-02-01

    Full Text Available Since 1998 clams (Chamelea gallina from the production areas of the district of San Benedetto del Tronto (South Marche - Italy have been periodically monitored to check the microbiological quality by the detection of the faecal indicator E. coli (MPN method. Results have been inconstant. They were not directly related to contamination sources identified by means of a Sanitary Survey. This one included a desk-based study of the physical, geographic, demographic and urban features of the district above and a shoreline survey to confirm or update previously identified sources. With regard to this, several authors found out that meteoric events, in particular rainfalls, increase faecal loading in marine coastal water. This study investigated the impact of rainfalls on E. coli values in clams from the district of San Benedetto del Tronto according to the sampling plan from 2002 to 2011. The study focused on rainfalls occurred until 4 days before mollusc sampling and set up E. coli values into satisfactory and unsatisfactory levels compared to the food safety limit of 230 MPN/100 g. Data were processed by a statistical tool, the Fisher’s exact test. Results revealed the association between precipitations and exceeding values of E. coli in clams collected from coastal waters of most populous areas to be statistically significant.

  15. Toxicological effects induced by cadmium in gills of Manila clam ruditapes philippinarum using NMR-based metabolomics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Linbao; Liu, Xiaoli; You, Liping; Zhou, Di [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China); The Graduate School of Chinese Academy of Sciences, Beijing (China); Yu, Junbao; Zhao, Jianmin; Wu, Huifeng [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China); Feng, Jianghua [Department of Electronic Science, Fujian Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen (China)

    2011-11-15

    Cadmium (Cd) has become an important heavy metal contaminant in the sediment and seawater along the Bohai Sea and been of great ecological risk due to its toxic effects to marine organisms. In this work, the toxicological effects caused by environmentally relevant concentrations (10 and 40 {mu}g L{sup -1}) of Cd were studied in the gill tissues of Manila clam Ruditapes philippinarum after exposure for 24, 48, and 96 h. Both low (10 {mu}g L{sup -1}) and high (40 {mu}g L{sup -1}) doses of Cd caused the disturbances in energy metabolism and osmotic regulation and neurotoxicity based on the metabolic biomarkers such as succinate, alanine, branched chain amino acids, betaine, hypotaurine, and glutamate in clam gills after 24 h of exposure. However, the recovery of toxicological effects of Cd after exposure for 96 h was obviously observed in clam to Cd exposures. Overall, these results indicated that NMR-based metabolomics was applicable to elucidate the toxicological effects of heavy metal contaminants in the marine bioindicator. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Shell Shape Analysis and Spatial Allometry Patterns of Manila Clam (Ruditapes philippinarum in a Mesotidal Coastal Lagoon

    Directory of Open Access Journals (Sweden)

    Nathalie Caill-Milly

    2012-01-01

    Full Text Available While gradual allometric changes of shells are intrinsically driven by genotype, morphometrical shifts can also be modulated by local environmental conditions. Consequently the common use of a unique dimension (usually length to assess bivalves’ growth may mask phenotypic differences in valve shape among populations. A morphometric exhaustive study was conducted on Manila clam, Ruditapes philippinarum, by acquiring data in the French Arcachon Bay (intrasite phenotypic variability and by comparing with other sites in the literature (intersite phenotypic variability. 2070 shells were subsampled, weighted, and automatically measured using TNPC software. Some ratios’ values indicate a relatively round and globular shape shell in comparison with other sites confirming poor conditions for some individuals. Among adult clams, three main morphological groups were identified and discussed according to spatial considerations. Allometric relations for pairs of shell descriptors were determined by testing classical linear and piecewise regression models on log-transformed relation of Huxley. A significant shape change correlated to size was observed; it corresponds to the second year of life of the clam. Relationships between density, disease, and shell shape are demonstrated and discussed related to other potential factors affecting shell shape. Finally, consequences on population regulation are addressed.

  17. A novel method to detect seven microcystins in hard clam and corbicula fluminea by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yang, Bo; Xu, Jin-Zhong; Ding, Tao; Wu, Bin; Jing, Su; Ding, Shu-jing; Chen, Hui-Lan; Sheng, Chong-Yu; Jiang, Yuan

    2009-11-01

    A simple and reliable method to detect seven microcystins in hard clam and corbicula fluminea, based on liquid chromatography with electrospray ionization and tandem mass spectrometry (LC-ESI-MS/MS), was developed and validated. The sample preparation procedure includes extraction of tissue by methanol, followed by cleanup on a reversed-phase solid phase extraction (SPE) cartridge. With the optimized method, recoveries were between 43.7% and 92.3% for hard clam, 54.3% and 93.8% for corbicula fluminea, the relative standard deviations (RSD) were less than or equal to 16.2% and 15.7% in hard clam and corbicula fluminea at spiking levels of 1 microg/kg, 2 microg/kg and 5 microg/kg for MC-RR, MC-YR, MC-LR, and MC-LY, and 2 microg/kg, 5 microg/kg and 10 microg/kg for MC-LA, MC-LW and MC-LF, respectively, the limits of quantitation (LOQ) of this method were ranged from 0.7 microg/kg to 2.0 microg/kg.

  18. Risk-based approach to appraise valve closure in the clam Corbicula fluminea in response to waterborne metals

    Energy Technology Data Exchange (ETDEWEB)

    Liao, C.-M. [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan 10617 (China)]. E-mail: cmliao@ntu.edu.tw; Jou, L.-J. [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan 10617 (China); Department of Biomechatronic Engineering, National Ilan University, Ilan, Taiwan 260 (China); Chen, B.-C. [Department of Post-Modern Agriculture, Mingdao University, Changhua, Taiwan 52345 (China)

    2005-05-01

    We developed a risk-based approach to assess how the valve closure behavior of Asiatic clam Corbicula fluminea responds to waterborne copper (Cu) and cadmium (Cd). We reanalyzed the valve closure response data from published literature to reconstruct the response time-dependent dose-response profiles based on an empirical three-parameter Hill equation model. We integrated probabilistic exposure profiles of measured environmental Cu and Cd concentrations in the western coastal areas of Taiwan with the reconstructed dose-response relationships at different integration times of response to quantitatively estimate the valve response risk. The risk assessment results implicate exposure to waterborne Cu and Cd may pose no significant risk to clam valve activity in the short-time response periods (e.g., <30 min), yet a relative high risk for valve closure response to waterborne Cu at response times greater than 120 min is alarming. We successfully linked reconstructed dose-response profiles and EC50-time relationships associated with the fitted daily valve opening/closing rhythm characterized by a three-parameter lognormal function to predict the time-varying bivalve closure rhythm response to waterborne metals. We parameterized the proposed predictive model that should encourage a risk-management framework for discussion of future design of biological monitoring systems. - A model was developed to link valve closure in clams to concentrations of metals in water.

  19. Atypical feeding behavior of Long-tailed Ducks in the wake of a commercial fishing boat while clamming

    Science.gov (United States)

    Perry, Matthew; Osenton, Peter C.; White, Timothy P.

    2017-01-01

    A foraging group of Clangula hyemalis (Long-tailed Duck) was observed on 10 February 2010 diving behind a commercial boat that was clamming near Monomoy Island, Nantucket Sound, MA. We used a shotgun to collect 9 of the ducks, and our analyses of gizzard and gullet (esophagus and proventriculus) revealed 37 food items in the gizzard and 16 in the gullet. Mollusca were the dominant food in the gizzard (49%), whereas Crustacea were dominant in the gullet (57%). Crustacea were the second most important food in the gizzard (38%), whereas Mollusca were the second most important food in the gullet (31%). Relatively high volumes of the Amphipoda Caprella sp. (skeleton shrimp) and the Decopoda Crangon septemspinosa (Sand Shrimp) were recorded in the gullet and gizzard. Ensis directus (Atlantic Jackknife Clam) formed the greatest volume of Mollusca in the gizzard (15%) and in the gullet (15%). Long-tailed Ducks had fed on this Bivalvia and several other species of Mollusca that had no shell or broken shell when consumed. Many of the food organisms were apparently dislodged and some damaged by the clamming operation creating an opportunistic feeding strategy for the Long-tailed Ducks.

  20. Freshwater Clams (Pilsbryoconcha Exilis) as an Potential Local Mineral Sources in Weaning Food to Overcome Stunting in Grobogan, Central Java, Indonesia

    Science.gov (United States)

    Putri, S. R.; Anjani, Gemala; Wijayanti, Hartanti Sandi; Nuryanto

    2018-02-01

    Based on a preliminary survey in Grobogan Central Java, one of the local food that has a prospective nutrient content developed is freshwater clams. Results of PSG report in 2015, especially in Grobogan district with stunting problem of 31.5% consisting of 7.2% very short and 24.1% short. From the stunting event factor, the role of weaning food in the form of baby porridge is the most important component in the fulfillment of infant nutrition. The research is divided into two stages of the research is the initial stage to make the formulation process by way of freshwater clams, nutrient analysis, and formula calculation. The second stage is the process of formulation weaning food by way of formula making, nutrient analysis, and acceptance test of weaning food on the baby slurry is substituted by the freshwater clams. The influence statistically different substitution of freshwater clams on protein content (p=0.014), fat (p=0,041), carbohydrate (p=0,039), water (p=0,0001), ash (p=0.0001), iron (p=0.0001), and zinc (p=0.0001). There is no influence substitution of freshwater clams on energy content (p=0,129) and fiber (p=0,225). The percentage of favorite level on the acceptance test of color (p=0,005) and taste (p=0,006) was statistically different, but there was no difference flavour (p=0,913) and texture (p=0,198). freshwater clams flour is rich in iron and zinc content, so it can serve as local food, especially in Grobogan Central Java as a stunting handling. Obtained from the results of several formulations substituted of freshwater clams in formulation 2 is a formula that can meet the standards of KEPMENKES except on the content of protein and moisture content. Formula 2 acceptable to the panelists, except for the assessment of taste.

  1. Tactile sensibility on the fingernail.

    Science.gov (United States)

    Seah, Benjamin Zhi Qiang; Wu, Clement Chun Ho; Sebastin, Sandeep Jacob; Lahiri, Amitabha

    2013-11-01

    To measure tactile discrimination (static and moving 2-point discrimination) and threshold levels (Weinstein enhanced sensory test) over the nail plate in normal subjects and compare these values with those at the corresponding finger pulps. Tactile discrimination and threshold values over the nail plates and finger pulps were measured on 300 digits in 30 healthy subjects with a mean age of 23 years. Subjects with cosmetic nail modifications, injuries, neurological deficits, dermatological conditions, or history of upper limb surgery were excluded. Equivalence testing was conducted to look for clinical equivalence between values obtained at both sites. The mean static 2-point discrimination, moving 2-point discrimination, and threshold value over the human nail were 6.7 mm, 2.4 mm, and 0.06 g, respectively. The corresponding values for the finger pulp were 2.4 mm, 2.2 mm, and 0.01 g, respectively. The static 2-point discrimination and threshold values were superior for the finger pulp, whereas moving 2-point discrimination values at both sites were clinically equivalent. Our study suggests that tactile discrimination and threshold levels can be measured over the nail plate and that moving 2-point discrimination values are clinically equivalent to those obtained on the corresponding pulp. This highlights the importance of the nail plate in the sensory function of the fingertip. The normative data from this study may be useful in establishing the impact of nail injury and the contribution of the nail to the overall function of the hand. Diagnostic II. Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  2. Razor clam (Ensis directus) shell as a low-cost adsorbent for the removal of Congo red and Rhodamine B dyes from aqueous solution

    Science.gov (United States)

    Areibat, Lila Elamari Mohamed; Kamari, Azlan

    2017-05-01

    Wastewater originating from industrial effluents contains many types of pollutants including dyes. Anionic and cationic dyes are very toxic and they can cause several problems to aquatic system. In present study, razor clam shell was used as a potential adsorbent to remove two classes of dyes, namely anionic (Congo red, CR) and cationic (Rhodamine B, RB) dyes from aqueous solution. Batch adsorption experiments were performed to study the effects of three experimental parameters, namely solution pH, adsorbent dosage and initial dye concentration, on adsorption capacity of CR and RB onto razor clam shell. Results indicated that pH 2.0 was optimum pH for adsorbent to adsorb both CR and RB. At an initial concentration of 20 mg/L, the removal percentages of CR and RB were 97% and 38%, respectively. The Freundlich and Langmuir isotherm models were used to describe adsorption behaviour of CR and RB, as well as the relationship between adsorbent and adsorbate. The adsorption equilibrium data were well fitted to Freundlich isotherm model. The separation factor (RL) constants suggest that both CR and RB were favourably adsorbed by razor clam shell. Razor clam shell was characterised by using two techniques, namely Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectrometry (FTIR). Overall, this study suggests that razor clam shell has great potential to be an alternative to expensive adsorbents.

  3. iTRAQ-based quantitative proteomics reveals the biochemical mechanism of cold stress adaption of razor clam during controlled freezing-point storage.

    Science.gov (United States)

    Wang, Chong; Chu, Jianjun; Fu, Linglin; Wang, Yanbo; Zhao, Feng; Zhou, Deqing

    2018-05-01

    Razor clam is a major cultivated shellfish of great economic importance and high nutritional value. Due to high corruptible potential, razor clam is generally preserved by controlled freezing-point storage (CFPS). Here, we applied isobaric tags for relative and absolute quantification (iTRAQ) labeling to investigate the biochemical mechanism of cold stress adaption in razor clam during CFPS. In total, 369 proteins were quantified, and 27 of them were identified as differentially expressed proteins during CFPS, mostly involved in energy metabolism process, DNA duplication and protein synthesis, and stress response, specifically, MAPK is the predominant pathway. Further qPCR results revealed H2A and S6K 2 alpha to be the critical post-transcriptionally regulated genes. Our results provided proteomics information with respect to the biochemical mechanism of cold stress adaption in razor clam, shed light on the further elongation of razor clams storage period, and help clarify the novel mechanisms of cold tolerance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Microcystin uptake and biochemical responses in the freshwater clam Corbicula leana P. exposed to toxic and non-toxic Microcystis aeruginosa: Evidence of tolerance to cyanotoxins

    Directory of Open Access Journals (Sweden)

    Thanh-Luu Pham

    2015-01-01

    Full Text Available We investigated the accumulation and adverse effects of toxic and non-toxic Microcystis in the edible clam Corbicula leana. Treated clams were exposed to toxic Microcystis at 100 μg of MC (microcystin-LReq L−1 for 10 days. The experimental organism was then placed in toxin-free water and fed on non-toxic Microcystis for the following 10 days for depuration. Filtering rates (FRs by C. leana of toxic and non-toxic Microcystis and of the green alga Chlorella vulgaris as a control were estimated. Adverse effects were evaluated though the activity of catalase (CAT, superoxide dismutase (SOD and glutathione S-transferase (GST. Clam accumulated MCs (up to 12.7 ± 2.5 μg g−1 dry weight (DW of free MC and 4.2 ± 0.6 μg g−1 DW of covalently bound MC. Our results suggest that although both toxic and non-toxic cyanobacteria caused adverse effects by inducing the detoxification and antioxidant defense system, the clam was quite resistant to cyanotoxins. The estimated MC concentration in C. leana was far beyond the World Health Organization's (WHO provisional tolerable daily intake (0.04 μg kg−1 day−1, suggesting that consuming clams harvested during cyanobacterial blooms carries a high health risk.

  5. Nutrients and clam contamination by Escherichia coli in a meso-tidal coastal lagoon: Seasonal variation in counter cycle to external sources

    International Nuclear Information System (INIS)

    Botelho, Maria João; Soares, Florbela; Matias, Domitília; Vale, Carlos

    2015-01-01

    Highlights: • Sources of nutrients and E. coli in Ria Formosa linked to tourism in summer. • Lower nutrient values and clam contamination by E. coli in summer. • Bactericide effect of temperature and solar radiation causes lower E. coli. • Higher biological consumption of nutrients in warmer periods. • Results mirror possible effects of climate changes on coastal lagoons. - Abstract: The clam Ruditapes decussatus was transplanted from a natural recruitment area of Ria Formosa to three sites, surveyed for nutrients in water and sediments. Specimens were sampled monthly for determination of Escherichia coli, condition index and gonadal index. Higher nutrient values in low tide reflect drainage, anthropogenic sources or sediment regeneration, emphasising the importance of water mixing in the entire lagoon driven by the tide. Despite the increase of effluent discharges in summer due to tourism, nutrient concentrations and E. coli in clams were lower in warmer periods. The bactericide effect of temperature and solar radiation was better defined in clams from the inlet channel site than from sites closer to urban effluents. High temperature in summer and torrential freshwater inputs to Ria Formosa may anticipate climate change scenarios for south Europe. Seasonal variation of nutrients and clam contamination may thus point to possible alterations in coastal lagoons and their ecosystem services

  6. Toxicity and the fractional distribution of trace metals accumulated from contaminated sediments by the clam Scrobicularia plana exposed in the laboratory and the field

    Energy Technology Data Exchange (ETDEWEB)

    Kalman, J., E-mail: judit.kalman@uca.es [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Bonnail-Miguel, E. [Department of Physical-Chemistry, University of Cadiz, Poligono Industrial Rio San Pedro s/n, 11,510 Puerto Real, Cadiz (Spain); Smith, B.D. [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Bury, N.R. [Division of Diabetes and Nutritional Science, King' s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH (United Kingdom); Rainbow, P.S. [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom)

    2015-02-15

    The relationship between the subcellular distribution of accumulated toxic metals into five operational fractions (subsequently combined into presumed detoxified and non-detoxified components) and toxicity in the clam Scrobicularia plana was investigated under different laboratory exposures. Clams were exposed to metal contaminated media (water and diet) and analysed for the partitioning of accumulated As, Cu and Zn into subcellular fractions. In general, metallothionein-like proteins, metal-rich granules and cellular debris in different proportions acted as main storage sites of accumulated metals in the clam soft tissues for these three metals. No significant differences were noted in the accumulation rates of As, Cu and Zn of groups of individuals with or without apparent signs of toxicity after up to 30 days of exposure to naturally contaminated sediment mixtures. There was, however, an increased proportional accumulation of Cu in the non-detoxified fraction with increased Cu accumulation rate in the clams, suggesting that the Cu uptake rate from contaminated sediments exceeded the combined rates of elimination and detoxification of Cu, with the subsequent likelihood for toxic effects in the clams. - Highlights: • Scrobicularia plana accumulated As, Cu and Zn from naturally toxic sediments. • Toxic metals were accumulated in detoxified and non-detoxified components. • Cu accumulation in the non-detoxified pool increased with increased Cu uptake rate. • Cu uptake rate exceeded combined loss and detoxification rates to cause toxicity.

  7. Development of a Taqman real-time PCR assay for rapid detection and quantification of Vibrio tapetis in extrapallial fluids of clams

    Directory of Open Access Journals (Sweden)

    Adeline Bidault

    2015-12-01

    Full Text Available The Gram-negative bacterium Vibrio tapetis is known as the causative agent of Brown Ring Disease (BRD in the Manila clam Venerupis (=Ruditapes philippinarum. This bivalve is the second most important species produced in aquaculture and has a high commercial value. In spite of the development of several molecular methods, no survey has been yet achieved to rapidly quantify the bacterium in the clam. In this study, we developed a Taqman real-time PCR assay targeting virB4 gene for accurate and quantitative identification of V. tapetis strains pathogenic to clams. Sensitivity and reproducibility of the method were assessed using either filtered sea water or extrapallial fluids of clam injected with the CECT4600T V. tapetis strain. Quantification curves of V. tapetis strain seeded in filtered seawater (FSW or extrapallial fluids (EF samples were equivalent showing reliable qPCR efficacies. With this protocol, we were able to specifically detect V. tapetis strains down to 1.125 101 bacteria per mL of EF or FSW, taking into account the dilution factor used for appropriate template DNA preparation. This qPCR assay allowed us to monitor V. tapetis load both experimentally or naturally infected Manila clams. This technique will be particularly useful for monitoring the kinetics of massive infections by V. tapetis and for designing appropriate control measures for aquaculture purposes.

  8. Accumulation and elimination profiles of paralytic shellfish poison in the short-necked clam Tapes japonica fed with the toxic dinoflagellate Gymnodinium catenatum.

    Science.gov (United States)

    Samsur, Mohamad; Takatani, Tomohiro; Yamaguchi, Yasunaga; Sagara, Takefumi; Noguchi, Tamao; Arakawa, Osamu

    2007-02-01

    The paralytic shellfish poison (PSP)-producing dinoflagellate Gymnodinium catenatum (Gc) was fed to the short-necked clam Tapes japonica, and the accumulation, transformation and elimination profiles of PSP were investigated by means of high-performance liquid chromatography with postcolumn fluorescence derivatization (HPLC-FLD). The short-necked clams ingested most of the Gc cells (4 x 10(6) cells) supplied as a bolus at the beginning of the experiment, and accumulated a maximal amount of toxin (181 nmol/10 clams) after 12 hr. The rate of toxin accumulation at that time was 16%, which rapidly decreased thereafter. During the rearing period, a variation in toxin composition, derived presumably from the transformation of toxin analogues in the clams, was observed, including a reversal of the ratio of C2 to C1, and the appearance of carbamate (gonyautoxin (GTX) 2, 3) and decarbamoyl (dc) derivatives (decarbamoylsaxitoxin (dcSTX) and dcGTX2, 3), which were undetectable in Gc cells. The total amount of toxin contained in clams and residue (remaining Gc cells and/or excrement in the rearing tank) gradually declined, and only about 1% of the supplied toxin was detected at the end of the experiment.

  9. Enhanced trace element concentrations in tissues of the clam Ruditapes decussatus transplanted to areas influenced by human activities (Ria Formosa, Portugal

    Directory of Open Access Journals (Sweden)

    Maria João Botelho

    2017-06-01

    Full Text Available To examine the extent to which human activities near the Ria Formosa coastal lagoon influence the accumulation of trace elements (TE in Ruditapes decussatus, individuals were transplanted from a natural bank located in the lower lagoon to three sites located in clam growth grounds under the influence of a small city (Faro, a fish farming centre (Olhão and a site near the lagoon inlet (Lavajo. Concentrations were determined in substrate of the clam grounds and in the digestive gland, gills, mantle plus siphons, and remaining tissues of clams in four periods of the year. These measurements were accomplished with the monthly survey of the gametogenic stages, condition index, proteins, glycogen, total lipids, pH and osmolarity of hemolymph. Arsenic, Cu, Mn, V, Cr and Pb were preferentially linked to the digestive gland, while Cd was linked to the gills. TE concentrations in the digestive gland and remaining tissues were higher in winter, most likely reflecting additional inputs associated with rain. The lack of disruptions in biological parameters and the prolonged period of spawning and gonad recovery in clams suggest that the current TE availability in the lagoon has a minor influence on the reproductive cycle and hence on clam production.

  10. Thermal tolerance of the adult Asiatic clam Corbicula manilensis (Mollusca:Bivalvia)

    International Nuclear Information System (INIS)

    Mattice, J.S.; Dye, L.L.

    1975-01-01

    Knowledge of the thermal tolerance of Corbicula manilensis is important for antifouling at water intakes and protection below discharges. Groups of 20 clams were acclimated to temperatures ranging between 5 and 32 0 C and exposed continuously to higher temperatures (24-39 0 C), continuously to lower temperatures (2 to 20 0 C), or for 30 minutes to temperatures between 37 and 43 0 C. Mortality was determined by lack of response to prying open the valves. Exposure to temperatures between 40 (5 0 C Acclimation) and 43 0 C (30 0 C Acclimation) for 30 minutes caused 100 per cent mortality. For continuous exposures, upper tolerance limits (50 per cent) were between 24 (5 0 C Acclimation) and 34 0 C (30 0 Acclimation) and lower tolerance limits were between 2 (15 0 C Acclimation) and 12 0 C (30 0 C Acclimation). Relationships between acclimation and resistance temperatures were linear. The upper incipient lethal temperature was 34 0 C. Use of results at 24 and 48 hours (and 96 hours for long-term heat stress) yielded significant overestimates of tolerance limits. (U.S.)

  11. Is metal contamination responsible for increasing aneuploidy levels in the Manila clam Ruditapes philippinarum?

    KAUST Repository

    Piló, D.

    2016-11-03

    The present study assessed the metal genotoxicity potential at chromosome-level in the bivalve Ruditapes philippinarum collected along different areas of the Tagus estuary. Higher levels of aneuploidy on gill cells were detected at the most sediment contaminated area both in May (31.7%) and October (36.0%) when compared to a less contaminated area over the same periods (20.3% and 29.0% respectively). Interestingly, metal bioaccumulation in gills was higher in the specimens collected at the least contaminated area with the exception of Pb. Indeed, the multivariate analysis revealed a stronger relation between aneuploidy and sediment contamination than between aneuploidy and the bioaccumulation of the metals. The temporal and spatial inconsistency found for the bioaccumulation of metals in R. philippinarum and the positive correlation between sediment contamination and aneuploidy at the most contaminated area suggest that these chromosome-level effects might be due to chronic metal contamination occurring in the Tagus estuary, rather than a direct result of the temporal variation of bioavailable contaminants. The vertical transmission phenomenon of bivalve aneuploidy levels may then be perpetuating those levels on clams from the most contaminated area. The present results shed light about the effect of metal toxicity at the chromosome-level in species inhabiting chronic contaminated areas and highlight the use of aneuploidy as an effective tool to identify persistent contamination in worldwide transitional waters.

  12. Morphometry, growth and reproduction of an Atlantic population of the razor clam Ensis macha (Molina, 1782

    Directory of Open Access Journals (Sweden)

    Pedro J. Barón

    2004-06-01

    Full Text Available Ensis macha is a razor clam distributed throughout the coasts of southern Argentina and Chile. Even though it represents a valuable fishery resource, the exploitation of its Atlantic populations has begun only in recent years. This study provides the first estimates of growth rate, an interpretation of the reproductive cycle on the coast of the northern Argentine Patagonia and an analysis of the species morphometry. Growth was estimated by direct observation of growth rings on the valves by two observers. The reproductive cycle was interpreted by the analysis of temporal change of oocyte size frequency distributions. Parameter estimations for the von Bertalanffy equations respectively obtained by observers 1 and 2 were 154 and 153.7 mm for L?, 0.25 and 0.20 yr-1 for k, and -0.08 and -0.72 yr for t0. Two spawning peaks were detected: September-November 1999 and May-June 2000. However, mature females were found all year round. An abrupt change in the relationship between shell length and height was detected at 11.2 mm length.

  13. Capillary crystallization and molecular-replacement solution of haemoglobin II from the clam Lucina pectinata

    International Nuclear Information System (INIS)

    Gavira, José A.; Jesus, Walleska de; Camara-Artigas, Ana; López-Garriga, Juan; García-Ruiz, Juan M.

    2006-01-01

    The haemoglobin II from the clam L. pectinata has been crystallized using counter-diffusion in single capillary in the presence of agarose to improve crystal quality. Initial phases have been obtained by molecular replacement. Haemoglobin II is one of three haemoglobins present in the cytoplasm of the Lucina pectinata mollusc that inhabits the Caribbean coast. Using HBII purified from its natural source, crystallization screening was performed using the counter-diffusion method with capillaries of 0.2 mm inner diameter. Crystals of HbII suitable for data collection and structure determination were grown in the presence of agarose at 0.1%(w/v) in order to improve their quality. The crystals belong to the tetragonal space group P4 2 2 1 2, with unit-cell parameters a = b = 73.92, c = 152.35 Å, and diffracted X-rays to a resolution of better than 2.0 Å. The asymmetric unit is a homodimer with a corresponding Matthews coefficient (V M ) of 3.15 Å 3 Da −1 and a solvent content of 61% by volume

  14. Predicting bioavailability and bioaccumulation of arsenic by freshwater clam Corbicula fluminea using valve daily activity.

    Science.gov (United States)

    Chen, Wei-Yu; Liao, Chung-Min; Jou, Li-John; Jau, Sheng-Feng

    2010-10-01

    There are many bioindicators. However, it remains largely unknown which metal-bioindicator systems will give the reasonable detection ranges of bioavailable metals in the aquatic ecosystem. Various experimental data make the demonstration of biomonitoring processes challenging. Ingested inorganic arsenic is strongly associated with a wide spectrum of adverse health outcomes. Freshwater clam Corbicula fluminea, one of the most commonly used freshwater biomomitoring organisms, presents daily activity in valve movement and demonstrates biotic uptake potential to accumulate arsenic. Here, a systematical way was provided to dynamically link valve daily activity in C. fluminea and arsenic bioavailability and toxicokinetics to predict affinity at arsenic-binding site in gills and arsenic body burden. Using computational ecotoxicology methods, a valve daily rhythm model can be tuned mathematically to the responsive ranges of valve daily activity system in response to varied bioavailable arsenic concentration. The patterned response then can be used to predict the site-specific bioavailable arsenic concentration at the specific measuring time window. This approach can yield predictive data of results from toxicity studies of specific bioindicators that can assist in prediction of risk for aquatic animals and humans.

  15. Toxicological effects and bioaccumulation in the freshwater clam (Corbicula fluminea) following exposure to trivalent arsenic.

    Science.gov (United States)

    Santos, H M; Diniz, M S; Costa, P M; Peres, I; Costa, M H; Alves, S; Capelo, J L

    2007-10-01

    Contamination of aquatic environments by arsenic is a serious worldwide problem. The main objective of this work was to evaluate the response of a freshwater clam (Corbicula fluminea) to arsenic (As III) exposure and infer its potential as a biological indicator of contamination. Metallothioneins (MTs) were used as indicators of metalloid toxicity in combination with an histological and histochemical evaluation. After a period of acclimatization in the laboratory, 50 C. fluminea (0.4 g +/- 0.1) were exposed to different nominal concentrations of arsenic (100, 300, 500, and 1000 microg L(-1)) for 7 days. The concentration of total As III in the water and in the tissues of the organisms was determined by atomic absorption spectrometry, and MTs were quantified through differential pulse polarography. Results suggest that the organisms exposed to the concentrations of 300 and 1000 microg As L(-1) accumulated the highest levels of As III in the tissues (17 +/- 9 and 15 +/- 3 microg g(-1) distilled water, respectively), which was confirmed through histochemical analysis. An apparent induction of MTs was also observed in the organisms exposed to As III, suggesting that C. fluminea possesses some capacity for arsenic regulation. The results suggest that the induction of MTs may be of high interest as a biomarker for arsenic contamination in aquatic environments, and confirms the potential of C. fluminea as a biological indicator. 2007 Wiley Periodicals, Inc.

  16. Effects of upper-limit water temperatures on the dispersal of the Asian clam Corbicula fluminea.

    Directory of Open Access Journals (Sweden)

    Inês Correia Rosa

    Full Text Available Temperature is a determinant environmental variable in metabolic rates of organisms ultimately influencing important physiological and behavioural features. Stressful conditions such as increasing temperature, particularly within high ranges occurring in the summer, have been suggested to induce flotation behaviour in Corbicula fluminea which may be important in dispersal of this invasive species. However, there has been no experimental evidence supporting this hypothesis. It was already proven that C. fluminea drift is supported by a mucilaginous drogue line produced by mucocytes present in the ctenidia. Detailed microscopic examination of changes in these cells and quantification of clam flotation following one, two and three weeks of exposure to 22, 25 and 30°C was carried out so that the effects of increasing water temperatures in dispersal patterns could be discussed. Results show that changes in temperature triggered an acceleration of the mucocytes production and stimulated flotation behaviour, especially following one week of exposure. Dilution of these effects occurred following longer exposure periods. It is possible that these bivalves perceive changing temperature as a stress and respond accordingly in the short-term, and then acclimate to the new environmental conditions. The response patterns suggest that increasing water temperatures could stimulate C. fluminea population expansion.

  17. Growth and overwinter survival of the Asiatic clam, Corbicula fluminea, in the St. Clair River, Michigan

    Science.gov (United States)

    French, John R. P.; Schloesser, Donald W.

    1991-01-01

    We report the discovery in April 1986 of the first population of Asiatic clam, Corbicula fluminea, known to occupy a lotic environment in the Laurentian Great Lakes system. This population occupied a 3.8 km long sandy shoal in the discharge plume of a steam-electric power plant on the St. Clair River (Michigan), the outflow of Lake Huron. Samples collected April 1986 to April 1987 revealed the growth of one-year-old Corbicula (1985 cohort) began after mid-May and ended by mid-November, while water temperatures were higher than 9°C. Maximum growth (0.78 mm wk-1) occurred between mid-August and mid-September, while water temperatures were about 16-23°C. We recorded a substantial overwinter mortality of the 1986 cohort, but not the 1985 cohort; this was particularly evident at sampling locations more remote from the heated discharge of the power plant, suggesting low water temperature wast the major mortality agent. The available information suggests low water temperature in the St. Clair River may limit the success of Corbicula in the river, including portions of populations inhabiting thermal plumes, by reducing growth, delaying the onset of sexual maturity and reproduction, and causing heavy overwinter mortality in the first year of life.

  18. Effects of upper-limit water temperatures on the dispersal of the Asian clam Corbicula fluminea.

    Science.gov (United States)

    Rosa, Inês Correia; Pereira, Joana Luísa; Costa, Raquel; Gonçalves, Fernando; Prezant, Robert

    2012-01-01

    Temperature is a determinant environmental variable in metabolic rates of organisms ultimately influencing important physiological and behavioural features. Stressful conditions such as increasing temperature, particularly within high ranges occurring in the summer, have been suggested to induce flotation behaviour in Corbicula fluminea which may be important in dispersal of this invasive species. However, there has been no experimental evidence supporting this hypothesis. It was already proven that C. fluminea drift is supported by a mucilaginous drogue line produced by mucocytes present in the ctenidia. Detailed microscopic examination of changes in these cells and quantification of clam flotation following one, two and three weeks of exposure to 22, 25 and 30°C was carried out so that the effects of increasing water temperatures in dispersal patterns could be discussed. Results show that changes in temperature triggered an acceleration of the mucocytes production and stimulated flotation behaviour, especially following one week of exposure. Dilution of these effects occurred following longer exposure periods. It is possible that these bivalves perceive changing temperature as a stress and respond accordingly in the short-term, and then acclimate to the new environmental conditions. The response patterns suggest that increasing water temperatures could stimulate C. fluminea population expansion.

  19. Valve movement response of the freshwater clam Corbicula fluminea following exposure to waterborne arsenic.

    Science.gov (United States)

    Liao, Chung-Min; Jau, Sheng-Feng; Lin, Chieh-Ming; Jou, Li-John; Liu, Chen-Wuing; Liao, Vivian Hsiu-Chuan; Chang, Fi-John

    2009-07-01

    We developed an inductance-based valvometry technique as a detection system to measure the valve daily activity in freshwater clam Corbicula fluminea in response to waterborne arsenic. Our findings reveal that C. fluminea experiences a valve opening in the absence of arsenic predominantly in the morning hours (03:00-08:00) with a mean daily opening/closing period of 21.32 (95% CI: 20.58-22.05) h. Amplification of daily activity occurred in the presence of arsenic. Behavioral toxicity assays revealed arsenic detection thresholds of 0.60 (95% CI: 0.53-0.66) mg l(-1) and 0.35 (95% CI: 0.30-0.40) mg l(-1) for response times of 60 and 300 min, respectively. The proposed valve daily activity model was linked with response time-specific Hill dose-response functions to predict valve opening/closing behavior in response to arsenic. The predictive capabilities were verified satisfactory with the measurements. Our results implicate a biomonitoring system by valve daily activity in C. fluminea to identify safe water uses in areas with elevated arsenic.

  20. Overfishing population characteristics of razor clam, Ensis macha, from Independencia Bay, Peru, in 2004 year

    Directory of Open Access Journals (Sweden)

    Juan Tarazona

    2011-05-01

    Full Text Available Quantitative monthly samplings, in 2004, were carried out to estimate the density and biomass of Ensis macha (Molina 1782, from Morro Quemado area, Bay Independence, Pisco. The present study analyzes biometric relationships, growth parameters and somatic production using the ELEFAN I routine and the Crisp’s method. During the year 2004 the rate of exploitation (E= 0.69 y-1 was significantly bigger than the values of 2003 and the monthly landings (maximum of 335 t and fishing effort (maximum of 848 trips were twice increased. These changes induced in the same year a significant decrease of population mean density (D= 54.13 ind. m-2 and the halfway reduction of somatic production (P= 81.99 gAFDW m-2 y-1 and P/B rate (0.38 y-1 values, regarding the values of the previous year. Also, a significant increment of total mortality rate (2.84 y-1 and the fishing mortality rate (1.97 y-1 were twice increased, regarding the previous year. It is assumed that the population of razor clams already was a overfishing commercial resource in the 2003 and that the increment of fishing pressure in the 2004, particularly during the second semester, intensified its overfishing resource condition.

  1. Identification and characterization of a novel phage-type like lysozyme from Manila clam, Ruditapes philippinarum.

    Science.gov (United States)

    Ding, Jianfeng; Wang, Rui; Yang, Feng; Zhao, Liqiang; Qin, Yanjie; Zhang, Guofan; Yan, Xiwu

    2014-11-01

    A novel lysozyme gene (RpLysPh) with high similarity to the bacteriophage lysozymes was identified in Manila clam, Ruditapes philippinarum. The full length cDNA of RpLysPh is 828bp and contains a 462bp open reading frame (ORF) that codes for a 154 amino acid protein. Multiple sequence alignment analysis revealed that the three residues essential for catalytic activity in phage-type lysozyme (Glu(20), Asp(29), and Thr(35)) are conserved in RpLysPh. The comparison of the 3D models of RpLysPh and Coxiella burnetii lysozyme also suggested that the active sites involved in the binding of substrate have similar conformations. Phylogenetic analysis suggested that RpLysPh shares a similar origin with the bacterial phage-type lysozyme group. The highest level of expression of RpLysPh was observed in hemocytes, followed by mantle. Induction of RpLysPh expression was observed in gills in response to lipopolysaccharide (LPS), peptidoglycan (PGN), polyinosinic-polycytidylic acid (Poly(I:C)), and whole glucan particles (WGP) challenge. The recombinant protein of RpLysPh showed antibacterial activity against both Gram-positive and Gram-negative bacteria. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Favored use of anti-predator netting (APN) applied for the farming of clams leads to little benefits to industry while increasing nearshore impacts and plastics pollution.

    Science.gov (United States)

    Bendell, L I

    2015-02-15

    An overview of the efficacy of anti-predator netting (APN) used by the shellfish industry is presented. There is little support that the currently favored APN effectively protects farmed clams from predators. Evidence does suggest that APN leads to impacts and pollution. APN is an attractant for predators, e.g., crabs, by providing a refuge within Ulva sp. which attaches onto the surface of APN. APN entrains silt and organic matter and increases sediment temperatures degrading habitat underneath the APN. APN present hazards to fish and wildlife and is a source of plastics to the marine environment. The continued use of ineffective APN does not serve either the environment or industry well, and many of these issues could be addressed through the alternate use of "ancient" technology used by aboriginal people to maintain clam gardens; building of rock walls optimizing the amount of clam habitat thereby increasing numbers without the use of APN. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Removal of Escherichia coli, Enterococcus fecalis, coliphage MS2, poliovirus, and hepatitis A virus from oysters (Crassostrea virginica) and hard shell clams (Mercinaria mercinaria) by depuration.

    Science.gov (United States)

    Love, David C; Lovelace, Greg L; Sobsey, Mark D

    2010-10-15

    Filter-feeding bivalve mollusks (shellfish) can bioaccumulate pathogenic microorganisms in up to 1000-fold higher levels than overlying waters, and therefore disease risks are associated with consuming raw or partially cooked shellfish. Many of these shellfish-borne diseases are due to enteric bacteria and viruses associated with fecal contamination. To control shellfish-borne diseases, guidelines for shellfish harvest waters and shellfish meat have been devised, which include cleansing of contaminated shellfish by depuration in controlled systems, heat pasteurization, or relay to clean waters. This study examines the depuration of oysters (Crassostrea virginica) and hard shell clams (Mercinaria mercinaria) in a flow-through depuration system under variable temperature (12 °C, 18 °C, and 25 °C), salinity (8 ppt, 18 ppt, and 28 ppt), turbidity (parameters of water temperature improved E. coli, MS2, poliovirus and HAV depuration, and optimized salinity improved E. coli, E. faecalis, and MS2 depuration rates. In hard shell clams, salinity improved E. coli and E. faecalis depuration rates. Adjusting turbidity, pH or algae did not improve microorganism depuration in either oysters or hard shell clams, with the exception of turbidity on E. faecalis in hard shell clams. Microorganism depuration rates in oysters from greatest to least were: MS2>E. coli>E. faecalis>poliovirus>HAV, and in clams depuration rates from greatest to least were: E. coli>E. faecalis>HAV>MS2>poliovirus. Because E. coli and E. faecalis were removed at faster rates than HAV and poliovirus, these fecal bacteria appear to be poor process indicators of the virological quality of depurated oysters and hard shell clams. Copyright © 2010 Elsevier B.V. All rights reserved.

  4. Can ecological history influence response to pollutants? Transcriptomic analysis of Manila clam collected in different Venice lagoon areas and exposed to heavy metal.

    Science.gov (United States)

    Milan, Massimo; Matozzo, Valerio; Pauletto, Marianna; Di Camillo, Barbara; Giacomazzo, Matteo; Boffo, Luciano; Binato, Giovanni; Marin, Maria Gabriella; Patarnello, Tomaso; Bargelloni, Luca

    2016-05-01

    Chronic exposure to environmental pollutants can exert strong selective pressures on natural populations, favoring the transmission over generations of traits that enable individuals to survive and thrive in highly impacted environments. The lagoon of Venice is an ecosystem subject to heavy anthropogenic impact, mainly due to the industrial activities of Porto Marghera (PM), which led to a severe chemical contamination of soil, groundwater, and sediments. Gene expression analysis on wild Manila clams collected in different Venice lagoon areas enabled to identify differences in gene expression profiles between clams collected in PM and those sampled in clean areas, and the definition of molecular signatures of chemical stress. However, it remains largely unexplored to which extent modifications of gene expression patterns persists after removing the source of contamination. It is also relatively unknown whether chronic exposure to xenobiotics affects the response to other chemical pollutants. To start exploring such issues, in the present study a common-garden experiment was coupled with transcriptomic analysis, to compare gene expression profiles of PM clams with those of clams collected in the less impacted area of Chioggia (CH) during a period under the same control conditions. Part of the two experimental groups were also exposed to copper for seven days to assess whether different "ecological history" does influence response to such pollutant. The results obtained suggest that the chronic exposure to chemical pollution generated a response at the transcriptional level that persists after removal for the contaminated site. These transcriptional changes are centered on key biological processes, such as defense against either oxidative stress or tissue/protein damage, and detoxification, suggesting an adaptive strategy for surviving in the deeply impacted environment of Porto Marghera. On the other hand, CH clams appeared to respond more effectively to copper

  5. Insights into the establishment of the Manila clam on a tidal flat at the southern end of an introduced range in Southern California, USA.

    Directory of Open Access Journals (Sweden)

    Drew M Talley

    Full Text Available Coastal ecosystem modifications have contributed to the spread of introduced species through alterations of historic disturbance regimes and resource availability, and increased propagule pressure. Frequency of occurrence of the Manila clam (Venerupis phillipinarum, Veneridae in Southern California estuaries has increased from absent or sparse to common since the mid-1990s. Potential invasion vectors include seafood sales and aquaculture, and spread from established northern populations over decades. The clam's post-settlement habitat preferences are, however, uncertain in this region. Our project aimed to identify factors associated with established patches of the clam within a bay toward the southern end of this introduced range. During summer 2013, we sampled 10 tidal flat sites in Mission Bay, San Diego; each containing an area with and without hard structure (e.g., riprap, boulders. We measured likely environmental influences (e.g., sediment variables, distance to ocean. Manila clam densities across the bay were most strongly associated with site, where highest densities were located in the northern and/or back halves of the bay; and weakly correlated with lower porewater salinities. Within sites, Manila clam density was enhanced in the presence of hard structure in most sites. Prevailing currents and salinity regimes likely contribute to bay wide distributions, while hard structures may provide suitable microhabitats (refuge from predators and physical stress and larval entrapment within sites. Results provide insights into decisions about future shoreline management efforts. Finally, we identify directions for future study to better understand and therefore predict patterns of establishment of the Manila clam in the southern portion of its introduced range.

  6. The impact of selection on population genetic structure in the clam Meretrix petechialis revealed by microsatellite markers.

    Science.gov (United States)

    Lu, Xia; Wang, Hongxia; Li, Yan; Liu, Baozhong

    2016-02-01

    The aim of our work is to evaluate the impact of mass selection on genetic structure in artificially closed populations of the clam Meretrix petechialis. In the present study, we performed mass selection over four generations (from 2004 to 2010) on two clam populations [shell features of purple lines (SP) and black dots (SB)] and analyzed their temporal genetic variation and structure using microsatellite makers. The two closed populations originated from the natural Shandong population (SD); thus, a natural SD population (10SD) was used to detect the current genetic structure after 6 years of natural selection. The results showed that the genetic diversity of the four generations of SB and SP was gradually reduced but remained at relatively high levels (SB, A = 18.9.4-16.8, Ho = 0.7389-0.6971, and He = 0.8897-0.8591; SP, A = 20.0-17.8, Ho = 0.7512-0.7043, and He = 0.8938-0.8625), which has not been reduced compared with that of the 10SD population (A = 17.8, Ho = 0.6803, and He = 0.8302). The Ne estimates for the two populations were almost at the same levels as the actual numbers of parental individuals. In addition, a low inbreeding coefficient was detected in the two populations (SB, 0.00201-0.00639; SP, 0.00176-0.00541). Based on the results, the present mass selection has not made a large impact on the population genetic structure of the closed populations. The present investigation provides important information for the development of management strategies for genetic breeding of the clam.

  7. Expression of a symbiosis-specific gene in Symbiodinium type A1 associated with coral, nudibranch and giant clam larvae

    KAUST Repository

    Mies, M.

    2017-05-24

    Symbiodinium are responsible for the majority of primary production in coral reefs and found in a mutualistic symbiosis with multiple animal phyla. However, little is known about the molecular signals involved in the establishment of this symbiosis and whether it initiates during host larval development. To address this question, we monitored the expression of a putative symbiosis-specific gene (H+-ATPase) in Symbiodinium A1 ex hospite and in association with larvae of a scleractinian coral (Mussismilia hispida), a nudibranch (Berghia stephanieae) and a giant clam (Tridacna crocea). We acquired broodstock for each host, induced spawning and cultured the larvae. Symbiodinium cells were offered and larval samples taken for each host during the first 72 h after symbiont addition. In addition, control samples including free-living Symbiodinium and broodstock tissue containing symbionts for each host were collected. RNA extraction and RT-PCR were performed and amplified products cloned and sequenced. Our results show that H+-ATPase was expressed in Symbiodinium associated with coral and giant clam larvae, but not with nudibranch larvae, which digested the symbionts. Broodstock tissue for coral and giant clam also expressed H+-ATPase, but not the nudibranch tissue sample. Our results of the expression of H+-ATPase as a marker gene suggest that symbiosis between Symbiodinium and M. hispida and T. crocea is established during host larval development. Conversely, in the case of B. stephanieae larvae, evidence does not support a mutualistic relationship. Our study supports the utilization of H+-ATPase expression as a marker for assessing Symbiodinium-invertebrate relationships with applications for the differentiation of symbiotic and non-symbiotic associations. At the same time, insights from a single marker gene approach are limited and future studies should direct the identification of additional symbiosis-specific genes, ideally from both symbiont and host.

  8. Spatial and overwinter changes in clam populations of San Pablo Bay, a semiarid estuary with highly variable freshwater inflow

    Science.gov (United States)

    Poulton, V.K.; Lovvorn, J.R.; Takekawa, John Y.

    2004-01-01

    In many estuaries worldwide, climate trends together with human diversion of fresh water have dramatically impacted the benthos. Such impacts have sometimes been complicated by exotic species, whose invasion and persistence can be mediated by wide variations in freshwater inflow. Monitoring such changes usually involves periodic samples at a few sites; but sampling that does not recognize variation at a range of spatial and seasonal scales may not reveal important benthic trends. San Pablo Bay, in northern San Francisco Bay, has extreme fluctuations in freshwater inflow. This bay also experienced a major benthic change with introduction of the Asian clam (Potamocorbula amurensis) in 1986. This species initially displaced the former community, but later appeared to vary in abundance depending on site and freshwater inflow. To investigate such patterns and provide guidelines for research and monitoring, we took 1746 core samples at six sites around San Pablo Bay from 19 October to 17 December 1999 and from 6 March to 19 April 2000. Most biomass consisted of the clams P. amurensis,Macoma balthica and Mya arenaria. Potamocorbula amurensis dominated the benthos at most sites in the fall and recruited a new cohort during winter, while there was weak recruitment in M. balthica and none in M. arenaria. At most but not all sites, densities of P. amurensis and M. arenaria declined dramatically over winter while M. balthica declined only slightly. The dominant clams had patch diameters >5 m at most but not all sites, and some showed inconsistent patch structure at scales of 100–1400 m. In this semiarid estuary with highly variable freshwater inflow, samples for research and monitoring should include multiple sites and seasons, and samples within sites should be ≥5 m apart to account for between-patch variation. Species abundance in winter 1999–2000 appeared to be affected by high freshwater inflows in 1997–1999, while spatial patterns were probably most affected by

  9. Size dependent bioaccumulation and ecotoxicity of gold nanoparticles in an endobenthic invertebrate: The Tellinid clam Scrobicularia plana

    International Nuclear Information System (INIS)

    Pan Jinfen; Buffet, Pierre-Emmanuel; Poirier, Laurence; Amiard-Triquet, Claude; Gilliland, Douglas; Joubert, Yolaine; Pilet, Paul; Guibbolini, Marielle; Risso de Faverney, Christine; Roméo, Michèle; Valsami-Jones, Eugenia; Mouneyrac, Catherine

    2012-01-01

    Gold nanoparticles (AuNPs) have important technological applications resulting in an increased potential for release to the environment, and a greater possibility of toxicological effects. The marine bivalve Scrobicularia plana was exposed to AuNPs of size 5, 15 and 40 nm during a 16 d laboratory exposure at 100 μg Au L −1 . After exposure to AuNPs forming aggregates (>700 nm), the clams accumulated Au in their soft tissues. Biochemical (biomarkers) and behavioral (burrowing and feeding) responses were investigated. Au NPs were responsible of metallothionein induction (5, 40 nm), increased activities of catalase (15, 40 nm) and superoxide dismutase (40 nm) and of glutathione S-transferase by the three sizes of AuNPs indicating defense against oxidative stress. Exposure to AuNPs impaired burrowing behavior. However, it must be underlined that these effects were observed at a dose much higher than expected in the environment. - Highlights: ► AuNPs were aggregated to a maximum distribution peak at 0.6 μm in seawater. ► Scrobicularia plana accumulated Au with higher accumulation for bigger NPs. ► Induction of MT, CAT, SOD and GST showed oxidative stress in clams. ► TBARS levels advocated no significant oxidative damage in clams. ► Gold is an inert metal, ecotoxic effects are probably due to the nanoparticle form. - AuNPs were aggregated in seawater, Scrobicularia plana accumulated Au with higher accumulation for bigger NPs and increased activities of biomarkers showed oxidative stress.

  10. Physiological effects of temperature and a herbicide mixture on the soft-shell clam Mya arenaria (Mollusca, Bivalvia).

    Science.gov (United States)

    Greco, Luna; Pellerin, Jocelyne; Capri, Ettore; Garnerot, Florent; Louis, Séverine; Fournier, Michel; Sacchi, Angela; Fusi, Marco; Lapointe, Dominique; Couture, Patrice

    2011-01-01

    The aim of the current study was to investigate effects of temperature and a mixture of herbicides on the physiological status of the bivalve Mya arenaria. Bivalves acclimated to two temperatures (7 and 18°C) were exposed for 28 d to 0.01 mg/L of a pesticide formulation containing dichlorophenoxyacetic acid (2,4-D), 2-(2-methyl-4-chlorophenoxy) propionic acid (mecoprop), and 3,6-dichloro-2-methoxybenzoic acid (dicamba). At days 7, 14, and 28, mortality, immune parameters (hemocyte number, phagocytic activity, and efficiency), biomarkers of oxidative stress (catalase [CAT] and superoxide dismutase [SOD] activities and malondialdehyde [MDA] content), the metabolic enzyme cytochrome C oxidase (CCO), a biomarker of pesticide exposure (acetylcholinesterase [AChE]), and the activity of an enzyme related to gametogenesis (aspartate transcarbamylase [ATCase]) were monitored in clam tissues. Gonadosomatic index (GSI), condition factor (CF), and sex were also assessed. In clams acclimated to 7°C, exposure to pesticide enhanced CCO activity and CF and decreased MDA content, hemocyte number, CAT, and SOD activities. In clams kept at 18°C, pesticide effects appeared minor compared with samples kept at 7°C. In bivalves acclimated to 18°C, CCO, SOD, and ATCase activity and MDA content were enhanced, and hemocyte number, CAT, and AchE activities and phagocytosis were suppressed. In samples exposed to pesticides, increased temperature enhanced MDA content and CCO and SOD activity and suppressed hemocyte number and CAT and AchE activity. A gradual sexual maturation was observed in both sexes through experimental time, but females had a higher sensitivity to temperature and pesticides compared to males. Increased temperature altered the ability of the sentinel species Mya arenaria to respond to pesticide exposures. Further work is needed to understand the impacts of increasing temperature on the whole St. Lawrence estuary ecosystem. © 2010 SETAC.

  11. Best management strategies for sustainable giant clam fishery in French Polynesia islands: answers from a spatial modeling approach.

    Directory of Open Access Journals (Sweden)

    Simon Van Wynsberge

    Full Text Available The giant clam Tridacna maxima has been largely overexploited in many tropical regions over the past decades, and was therefore listed in appendix II of the Convention of International Trade in Endangered Species (CITES in 1985. In French Polynesia, several atolls and islands harbor the world's highest stocks of giant clams in very shallow and accessible areas, which are therefore highly vulnerable to fishing pressure. The local fishery authority (i.e., Direction des Resources Marines or "DRM" implemented several management schemes in 2002 to control and regulate fishing pressure. However, for further decisions DRM was missing a sensitivity analysis on the effectiveness of the possible management actions. Here, we report on the use of a deterministic Viable Population Analysis (VPA and spatially-explicit age-based population model that simulated the 30-year trajectory of a Tridacna maxima stock under different management approaches. Specifically, given various scenarios of intra-island larval dispersal, we tested which of No-take-Areas (NTAs, rotational closures, size limits, quotas, and restocking schemes would lead to the highest future stocks in Tubuai and Raivavae, two exploited islands of the Austral archipelago. For both islands, stock abundances were estimated in 2004/2010 and 2005/2010 respectively, and natural mortalities were assessed previously only in Tubuai. When compared to field data, the model successfully predicted the 2010 stocks for Tubuai, but proved to be less reliable for Raivavae, where natural mortality rates may well be different from those on Tubuai. For Tubuai, the spatial model suggested that reducing fishing effort (through fixed quotas and banning fishing below the 12 cm size limit (as currently implemented were the most effective management actions to sustain T. maxima populations into the future. Implementing NTAs was of poor effectiveness. NTAs increased giant clam stock inside the protected area, but also

  12. Coping with seawater acidification and the emerging contaminant diclofenac at the larval stage: A tale from the clam Ruditapes philippinarum.

    Science.gov (United States)

    Munari, Marco; Chemello, Giulia; Finos, Livio; Ingrosso, Gianmarco; Giani, Michele; Marin, Maria G

    2016-10-01

    Seawater acidification could alter the susceptibility of marine organisms to emerging contaminants, such as pharmaceuticals. In this study, the combined effects of seawater acidification and the non-steroidal anti-inflammatory drug diclofenac on survival, growth and oxidative stress-related parameters (catalase activity and lipid peroxidation) in the larvae of the Manila clam Ruditapes philippinarum were investigated for the first time. An experimental flow-through system was set up to carry out a 96-h exposure of clam larvae. Two pH levels (pH 8.0, the control, and pH 7.8, the predicted pH by the end of this century) were tested with and without diclofenac (0.5 μg/L). After 4 days, mortality was dramatically higher under reduced pH, particularly in the presence of diclofenac (62% of the larvae dead). Shell morphology was negatively affected by both acidification and diclofenac from the first day of exposure. The percentage of abnormal larvae was always higher at pH 7.8 than in controls, peaking at 98% in the presence of diclofenac after 96 h. Instead, shell length, shell height or the ratio of these values were only negatively influenced by reduced pH throughout the whole experiment. After 96 h, catalase activity was significantly increased in all larvae kept at pH 7.8, whereas no significant difference in lipid peroxidation was found among the treatments. This study demonstrates a high susceptibility of R. philippinarum larvae to a slight reduction in seawater pH. Furthermore, the results obtained highlight that acidification enhances the sensitivity of clam larvae to environmentally relevant concentrations of diclofenac. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Settlement, mortality and growth of the asari clam (Ruditapes philippinarum) for a collapsed population on a tidal flat in Nakatsu, Japan

    Science.gov (United States)

    Tezuka, Naoaki; Kamimura, Satomi; Hamaguchi, Masami; Saito, Hajime; Iwano, Hideki; Egashira, Junichi; Fukuda, Yuichi; Tawaratsumida, Takahiko; Nagamoto, Atsushi; Nakagawa, Koichi

    2012-04-01

    Although fluctuation and decline in bivalve populations have been reported worldwide, the underlying processes are not yet fully understood. This lack of understanding is partly due to an absence of demographic information for the early post-settlement period. This is the case particularly for annual production of the asari clam (also commonly known as the Manila clam, Ruditapes philippinarum) in Japan, which has greatly decreased in recent years. A remarkable decrease has been observed in the Nakatsu tidal flat, where current yields are less than 0.02% of the maximum yield. Possible explanations for this decline are: 1. limitation on recruitment due to overfishing; and 2. the demographic processes of growth and mortality have been altered by environmental changes, such as rise in seawater temperature or decrease in phytoplankton abundance. However, because of a lack of demographic information (e.g., the initial densities of larval settlement and mortality and growth rates post-settlement), the reasons for the decline, and the relative importance of each period in the life cycle in determining population abundance, remain unclear. Despite the decline, we observed high levels of recruitment of 0-year-class clams on the Nakatsu tidal flat in spring 2005, where more than 10,000 individuals m- 2 3-5 mm in shell length, estimated to have settled during the previous autumn, were observed. To obtain demographic information on the Nakatsu clams, we investigated two factors. First, we investigated the distribution of the 0-year-class clams and their rate of change in density as a combination of mortality, emigration and immigration on the whole tidal flat after a year. Second, we investigated the rate of change in the density and growth of clams after settlement in the center of the flat for 3 years. The rate of decrease in the density of the 0-year-class clams over the whole tidal flat after a year was greater at the stations where the initial density was higher. This

  14. Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): Spatial distribution in agriculturally impacted estuaries

    International Nuclear Information System (INIS)

    Muttray, Annette; Reinisch, Carol; Miller, Jason; Ernst, William; Gillis, Patricia; Losier, Melanie; Sherry, James

    2012-01-01

    Intensive farming of potatoes in Prince Edward Island (PEI) relies on the repeated and widespread application of fertilizers and pesticides. In PEI the main potato farming areas are in close proximity and drain directly to estuaries. Runoff from high agricultural activity watersheds could impact benthic organism health in the depositional zone of downstream estuaries. The estuarine filter feeder Mya arenaria (soft-shell clam) could be particularly vulnerable to both particle-adsorbed and water soluble contaminants. M. arenaria is susceptible to haemocytic leukemia. In May 2009, we established that heavily proliferated leukemia (HPL) prevalence was generally higher in PEI estuaries located downstream of high intensity potato farming (Dunk and Wilmot estuaries) watersheds than in estuaries downstream of lower intensity areas. Using Mab-1E10 based immunocytochemistry we observed that leukemic haemocytes from the Dunk and Wilmot estuaries were 1E10 negative whereas those from the Ox/Sheep estuary (low potato farming intensity) were 1E10 positive. The expression of genes in the p53 tumour suppressor pathway enabled us to differentiate groups of leukemic and normal M. arenaria, validating our diagnoses. In October 2009, we confirmed that HPL prevalence was elevated in the Dunk and Wilmot estuaries compared to reference (Souris River). Moreover, leukemia prevalence declined with distance from the river mouths along transects through the Dunk and Wilmot estuaries. The pesticides ß-endosulfan and α-endosulfan were detected in surface sediments from the Dunk and Wilmot estuaries, but not in sediments from either the Souris River or several other lower intensity potato farming watersheds. Our study provides evidence of an association between intensity of potato farming and prevalence of clam leukemia at downstream estuaries in PEI. - Highlights: ► We examined leukemia prevalence in PEI clams Mya arenaria. ► Prevalence was generally higher downstream of high intensity

  15. Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): Spatial distribution in agriculturally impacted estuaries

    Energy Technology Data Exchange (ETDEWEB)

    Muttray, Annette, E-mail: amuttray@rescan.com [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Reinisch, Carol, E-mail: creinisch@mbl.edu [Visiting Scientist Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Miller, Jason, E-mail: j.miller@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Ernst, William, E-mail: bill.ernst@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 45 Alderney Drive, Dartmouth, NS, Canada B2Y 2N6 (Canada); Gillis, Patricia, E-mail: patty.gillis@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Losier, Melanie, E-mail: melanie.losier@ec.gc.ca [Environment Canada, Atlantic Laboratory for Environmental Testing, Environmental Science Centre, P.O. Box 23005 Moncton, NB, Canada E1A 6S8 (Canada); Sherry, James, E-mail: jim.sherry@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada)

    2012-05-01

    Intensive farming of potatoes in Prince Edward Island (PEI) relies on the repeated and widespread application of fertilizers and pesticides. In PEI the main potato farming areas are in close proximity and drain directly to estuaries. Runoff from high agricultural activity watersheds could impact benthic organism health in the depositional zone of downstream estuaries. The estuarine filter feeder Mya arenaria (soft-shell clam) could be particularly vulnerable to both particle-adsorbed and water soluble contaminants. M. arenaria is susceptible to haemocytic leukemia. In May 2009, we established that heavily proliferated leukemia (HPL) prevalence was generally higher in PEI estuaries located downstream of high intensity potato farming (Dunk and Wilmot estuaries) watersheds than in estuaries downstream of lower intensity areas. Using Mab-1E10 based immunocytochemistry we observed that leukemic haemocytes from the Dunk and Wilmot estuaries were 1E10 negative whereas those from the Ox/Sheep estuary (low potato farming intensity) were 1E10 positive. The expression of genes in the p53 tumour suppressor pathway enabled us to differentiate groups of leukemic and normal M. arenaria, validating our diagnoses. In October 2009, we confirmed that HPL prevalence was elevated in the Dunk and Wilmot estuaries compared to reference (Souris River). Moreover, leukemia prevalence declined with distance from the river mouths along transects through the Dunk and Wilmot estuaries. The pesticides ss-endosulfan and {alpha}-endosulfan were detected in surface sediments from the Dunk and Wilmot estuaries, but not in sediments from either the Souris River or several other lower intensity potato farming watersheds. Our study provides evidence of an association between intensity of potato farming and prevalence of clam leukemia at downstream estuaries in PEI. - Highlights: Black-Right-Pointing-Pointer We examined leukemia prevalence in PEI clams Mya arenaria. Black

  16. Genotoxic and biochemical effects of atrazine and Roundup(®), alone and in combination, on the Asian clam Corbicula fluminea.

    Science.gov (United States)

    dos Santos, Kelly Cristina; Martinez, Claudia B R

    2014-02-01

    The present study aimed to evaluate biochemical and genotoxic effects of the herbicides atrazine (ATZ) and Roundup(®) (RD) separately, as well as their mixture, on the freshwater clam Corbicula fluminea after 96 h exposure. Animals were exposed to 2 and 10 ppb of ATZ (ATZ2 and ATZ10), 2 and 10 ppm of RD (RD2 and RD10) and the following mixtures: 2 ppb ATZ+2ppm RD (AR2) and 10 ppb ATZ+10 ppm RD (AR10). Activities of ethoxyresorufin-O-deethylase (EROD), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR), as well as the multixenobiotic resistance mechanism (MXR), reduced glutathione concentrations (GSH) and lipid peroxidation (LPO) were measured in gills and digestive gland. DNA damage was determined in clams hemocytes through the comet assay. The gills were more susceptible to the action of the herbicides and the results showed that ATZ2 and ATZ10 caused a significant reduction in EROD and the mixture leads to a significant decrease in EROD and MXR. No significant change in the biotransformation parameters was observed in the digestive gland. Regarding the primary antioxidant defenses, SOD activity increased in the gills of clams exposed to ATZ10 and RD10 and in the digestive gland of animals exposed to RD2 and RD10, CAT activity was significantly reduced only in digestive gland of clams exposed RD10 while GPX increased in the gills after exposure to ATZ2 and RD10. The exposure to RD10 caused a significant increase in LPO in both gills and digestive gland. While the exposure to ATZ and RD separately did not increase DNA damage, the exposure to AR2 and AR10 caused a significant increase in the occurrence of DNA damage. In conclusion, this study showed that both herbicides applied alone caused effects on C. fluminea; ATZ interfered mostly in biotransformation while RD interfered mainly in antioxidant defenses leading to lipid peroxidation. The herbicides mixture showed antagonistic

  17. Baseline of organotin pollution in fishes, clams, shrimps, squids and crabs collected from the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Jadhav, S.; Bhosale, D.; Bhosle, N.B.

    of Karwar is around 36,000 tonnes. Mumbai coast is about 140 km long. Mumbai is among busiest harbours on the west coast of India is known for industrial pollution. The fishes, clams, crabs and squids and shrimps were collected from local fish markets...; Fishes; Butyltin degradation index; Phenyltin degradation index; Tolerable daily intake. *Corresponding author. Tel.: + 91 832 2450 537 Fax: + 91 832 2450 615 Email address: sangeeta.jadhav@gmail.com or sjadhav@nio.org (S Jadhav) 2 Industrial use...

  18. First study of Vibrios in larval cultures of pullet carpet shell clam (Venerupis corrugata in hatchery

    Directory of Open Access Journals (Sweden)

    Javier Dubert Pérez

    2014-07-01

    Full Text Available Protocol for hatchery culture of the pullet carpet shell clam Venerupis corrugata spat is currently under development, as the only reliable means of providing spat to replenish natural beds or to support aquaculture activities. Among other variables, the microbiota has been demonstrated to be critical for successful bivalve culture. Shellfish hatcheries are hindered by fatal outbreaks of disease, regardless the bivalve species. These mass mortalities are mainly caused by opportunistic bacteria belonging to genus Vibrio and constitute one bottleneck for this economic activity. Different species, as V. tubiashii, V. pectenicida, V. splendidus, V. neptunius, V. ostreicida and V. bivalvicida, have been identified as responsible of mortalities in hatchery-reared larvae, affecting a wide range of bivalves. This is the first report of the microbiota associated with larval cultures of the pullet carpet shell clam. We present the results of the microbiological analyses of two larval cultures of pullet carpet shell reared in the Centro de Investigacións Mariñas (CIMA, Xunta de Galicia de Ribadeo (Galicia, NW Spain following the procedures developed in the institution. Each batch, A and B, was obtained from broodstocks collected in natural environment but in different geographical locations, the stock A (SW Galicia and the stock B (NW Galicia. Previous records of mortalities led us to divide each batch in two. One sub-batch (A1 and B1 was cultured following the routine procedures. Antibiotic was experimentally added to the other sub-batch (A2 and B2 with the aim of evaluating the effects on the culturable bacterial population (total marine bacteria and presumptive vibrios and on larval survival. Chloramphenicol, formerly the most commonly used antibiotic in bivalve hatcheries, was supplied with each change of seawater during larval development. Microbiological samples of broodstock, larvae and seawater in culture tanks were taken and processed

  19. Toxicity assessment of ZnO-decorated Au nanoparticles in the Mediterranean clam Ruditapes decussatus.

    Science.gov (United States)

    Sellami, Badreddine; Mezni, Amine; Khazri, Abdelhafidh; Bouzidi, Imen; Saidani, Wiem; Sheehan, David; Beyrem, Hamouda

    2017-07-01

    The synthesis of hybrid nanomaterials has greatly increased in recent years due to their special physical and chemical properties. However, information regarding the environmental toxicity associated with these chemicals is limited, in particular in the aquatic environment. In the present study, an experiment was performed in which the marine bivalve (Ruditapes decussatus) was exposed for 14days to 2 concentrations of zinc oxide-decorated Au nanoparticles (Au-ZnONPs: Au-ZnONP50=50μg/L; Au-ZnONP100=100μg/L). The stability and resistance of Au-ZnONPs in the natural seawater were assessed by combining transmission electron microscopy and dynamic light scattering. Inductively coupled plasma-atomic emission spectroscopy revealed uptake of these nanoparticles within clams and their ability to induce metallic deregulation. The results obtained indicate that Au-ZnONPs induce biochemical and histological alterations within either the digestive gland or gill tissues at high concentration. This was deduced from the significant increase in H 2 O 2 level, superoxide dismutase and catalase activities and malondialdehyde content. Furthermore, the toxicity of Au-ZnO nanoparticles was linked with the increase of intracellular iron and calcium levels in both tissues. Histological alterations in gill and digestive gland were more pronounced with Au-ZnONP100 and this is likely related to oxidative mechanisms. Gill and digestive gland are differentially sensitive to Au-ZnONPs if the exposure concentration is higher than 50μg/L. In conclusion, the parameters considered here could constitute reliable biomarkers for evaluation of hybrid nanoparticles toxicity in environmental model organisms. In addition, based on the results obtained, gill and digestive gland of R. decussatus could be proposed as models to detect harmful effects of hybrid nanoparticles. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Effects of an in situ diesel oil spill on oxidative stress in the clam Anomalocardia flexuosa.

    Science.gov (United States)

    Sardi, Adriana E; Renaud, Paul E; Morais, Gisele C; Martins, César C; da Cunha Lana, Paulo; Camus, Lionel

    2017-11-01

    Intensive exploitation and transport of oil and derivatives are increasing the risk of coastal contamination by either dramatic disasters or diffuse sources. Tools for monitoring diffuse contamination, such as diesel oil that leaks from marine vessels are much needed. We experimentally tested the efficiency of antioxidant biomarkers as indicators of chronic exposure to diesel oil in a mudflat from the subtropical Bay of Paranaguá, in southern Brazil. We examined the effects of three successive diesel oil spills, with two weeks of recovery time between exposures, on the edible clam Anomalocardia flexuosa. Previous studies have highlighted its potential as a bioindicator species for diesel oil contamination in subtropical and tropical ecosystems. Endpoints measured in gill and digestive gland homogenates included the activity of antioxidant enzymes SOD, GPx, GST and levels of lipid peroxides. PAHs concentration in sediments and soft tissue were also quantified. GST and SOD were the most responsive biomarkers to the exposure. There were significant but non-cumulative departures from control levels in organisms from treated samples, which were, in all cases, more common 48 h after each experimental spill. Biomarker responses were more evident in the digestive gland than in gills. This work validated the short-term responsiveness of biomarkers as measures of repeated pulsed in situ exposure to low concentrations of diesel oil. For their routine implementation into monitoring programs for tropical estuaries our general recommendations are 1) to include several reference sites, 2) to analyze biomarker data using a logarithmic-scale and 3) to interpret deviations from "normal" activity as multiplicative interval differences. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A biomineralization study of the Indo-Pacific giant clam Tridacna gigas

    Science.gov (United States)

    Gannon, M. E.; Pérez-Huerta, A.; Aharon, P.; Street, S. C.

    2017-06-01

    The giant clam, Tridacna gigas, is an important faunal component of reef ecosystems of the Indo-Pacific region. In addition to its ecological role, shells of this bivalve species are useful bioarchives for past climate and environmental reconstructions. However, the biomineralization processes involved in shell aragonite deposition are insufficiently understood. Here, we present a study of the shell microstructure of modern specimens from Palm Island, Great Barrier Reef (GBR), Australia, and Huon Peninsula, Papua New Guinea (PNG), using a combination of petrography, scanning electron microscopy, electron backscatter diffraction, Raman spectroscopy and stable carbon isotope ratios. Daily growth increments were recognizable in all specimens through ontogeny, and counting these growth lines provides a robust specimen age estimate. For the internal layers, paired increments of organized aragonitic needles and compact, oblong crystals were recognized in a specimen from PNG, whereas specimens from GBR were composed of shield-like crystals that were not definable at the microscale. The combination of nutrient availability, rainfall and solar irradiance are likely to be the most significant factors controlling shell growth and may explain the observed differences in microstructure. The external layer, identical in all specimens, was composed of dendritic microstructure that is significantly enriched in 13C compared to the internal layer, suggesting different metabolic controls on layer deposition. We propose that the mineralization of the internal and external layers is independent from each other and associated with the activity of specific mantles. Future studies using T. gigas shells as bioarchives should consider the microstructure as it reflects the environment in which the individual lived and the differences in mineralization pathways of internal and external layers.

  2. [Carbon, nitrogen, and phosphorus budgets of bottom-cultured clam Ruditapes philippinarum].

    Science.gov (United States)

    Zhang, Sheng-li; Zhang, An-guo; Yuan, Xiu-tang; Liang, Bin; Liu, Shu-xi

    2015-04-01

    In order to elucidate the role of bottom-cultured clams in the coastal nutrient cycle, the seasonal filtration, ingestion and biodeposition rates were in situ measured and carbon (C), nitrogen (N) and phosphorus (P) budgets of Ruditapes philippinarum among four seasons were modeled. The results showed that the scope for growth of R. philippinarum in carbon (SFG(C)), nitrogen (SFG(N)), and phosphorus (SFG(P)) all varied significantly among seasons, with the highest values in spring. Meanwhile, SFG(C) was negative in summer, SFG(N) and SFG(P) were always positive throughout the year. The seasonal variations of SFG(C), SFG(N) and SFG(P) were -3.94-49.82 mg C x ind(-1) x d(-1), 0.72-9.49 mg N x ind(-1) x d(-1), and 0.15-3.06 mg P x ind(-1) x d(-1), respectively. The net growth efficiencies in carbon (K(C2)), nitrogen (K(N2)), and phosphorus (K(P2)) also showed a distinct seasonal pattern among seasons, and ranked as K(P2) > K(N2) > K(C2). The C, N, and P budgets illustrated that the R. philippinarum population relatively used more N and P than C for growth and efficiently transferred the pelagic primary production to a higher trophic level. The current study suggested that R. philippinarum bottom-cultured at large scale might play a dominant role in the nutrient cycle of the coastal ecosystem and should be considered as an important ecological component in coastal areas.

  3. Sterilization of freeze dried manila clam (Ruditapea philippinarum) porridge for immuno-compromised patients

    Energy Technology Data Exchange (ETDEWEB)

    Song, Beom Seok; Park, Jae Nam [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2017-02-15

    This study was conducted to evaluate the combined effect of gamma irradiation and different conditions (vacuum packaging, antioxidant and freezing) on the microbiological and sensory characteristics of freeze dried Manila clam porridge (MCP) for immuno-compromised patient food. McP can be sterilized at 1 kGy to 10 kGy. the initial counts of total aerobic bacteria and yeast molds in the non-irradiated MCP were 2.4±0.5 and 1.2±0.3 log CFU g{sup -}'1, respectively, but gamma irradiation significantly decreased the total aerobic bacteria to below the detection limit (1 log CFU g{sup -1}) (5 kGy). Moreover, gamma irradiation effectively eliminated yeasts/molds at dose below than 1 kGy. However, gamma irradiation accelerated the increase of lipid oxidation and therefore, decreased the sensory characteristics of MCP as irradiation dose increased. to improve the sensory qualities of gamma irradiated MCP, combination treatment (vacuum packaging, 0.1% vitamin c) were applied. there was no significant difference in the overall acceptance scores between the combined-treatment sample (5.6 points) and the non-irradiated samples (6.0). the results indicate that combination treatment (vacuum packaging, 0.1% vitamin c) may help to maintain the quality of MCP. therefore, it considered that irradiation of MCP with combined treatment and this is an effective method for the consumption as a special purpose food such as for space travel or immuno-compromised patients.

  4. Effect of cadmium in the clam Ruditapes decussatus assessed by proteomic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chora, Suze [University of Algarve, CIMA, Faculty of Marine and Environmental Sciences, Campus de Gambelas, 8000-139 Faro (Portugal); University of Nice-Sophia Antipolis EA 4228 ECOMERS ' Ecosystemes Cotiers Marins et Reponses aux stress' Parc Valrose, BP 71, 06108 Nice cedex 2 (France); Starita-Geribaldi, Mireille [University of Nice-Sophia Antipolis, Laboratory of Oral Microbiology, URE 01., Faculty of Odontology, Pole Universitaire Saint-Jean d' Angely, 24 avenue des Diables Bleus 06357 Nice cedex 4 (France); Guigonis, Jean-Marie [University of Nice-Sophia Antipolis, Plateforme Bernard Rossi - Proteome Metabolome IFR50, Nice, F-06107 (France); Samson, Michel [University of Nice-Sophia Antipolis, Plateforme Bernard Rossi - Proteome Metabolome IFR50, Nice, F-06107 (France); INSERM, Unite 638, Nice, F-06107 (France); Romeo, Michele [University of Nice-Sophia Antipolis EA 4228 ECOMERS ' Ecosystemes Cotiers Marins et Reponses aux stress' Parc Valrose, BP 71, 06108 Nice cedex 2 (France); Bebianno, Maria Joao, E-mail: mbebian@ualg.pt [University of Algarve, CIMA, Faculty of Marine and Environmental Sciences, Campus de Gambelas, 8000-139 Faro (Portugal)

    2009-10-04

    Cadmium, an environmental stressor due to its toxicity, persistence and accumulation in biota, is widespread in the aquatic environment. Cadmium accumulation kinetics have revealed that Ruditapes decussatus has a high affinity to this metal. Proteomics is an effective tool to evaluate the toxic effects of contaminants. The aim of this study was to investigate the Cd effects in the gill and digestive gland of the sentinel species R. decussatus. Protein expression profiles (PEPs) in the clam tissues exposed to Cd (40 {mu}g l{sup -1}, 21 days) were compared to unexposed ones. Cd induces major changes in tissue-specific protein expression profiles in gill and digestive gland. This tissue dependent response results mainly from differences in Cd accumulation, protein inhibition and/or autophagy. An overall decrease of protein spots was detected in both treated tissues, being higher in gill. Some of the spots more drastically altered after pollutants exposure were excised and nine were identified by micro liquid chromatography tandem mass spectrometry (LC-MS/MS). Proteins identified by homology search in databases included: three proteins (8-fold) up-regulated, one down-regulated, four suppressed and one induced. Cd induces major changes in proteins involved in cytoskeletal structure maintenance (muscle-type actin, adductor muscle actin and {beta}-tubulin), cell maintenance (Rab GDP) and metabolism (ALDH and MCAD, both identified by de novo sequencing) suggesting potential energetic change. They provide a valuable knowledge of Cd effects at biochemical and molecular levels in the gill and digestive gland of R. decussatus.

  5. Clams as CO2 generators: The Potamocorbula amurensis example in San Francisco Bay

    Science.gov (United States)

    Chauvaud, Laurent; Thompson, Janet K.; Cloern, James E.; Thouzeau, Gerard

    2003-01-01

    Respiration and calcium carbonate production by the invasive Asian clam, Potamocorbula amurensis, were calculated to assess their importance as CO2 sources in northern San Francisco Bay. Production, calculated using monthly population density and size structure measured at three sites over 7 yr and a shell length/CaCO3 conversion factor, averaged 221 (6184) g CaCO3 m22 yr21 . Net calcium carbonate production by this exotic bivalve releases CO2 at a mean rate of 18 (617) g C m22 yr21 . Respiration by P. amurensis, estimated from secondary production, releases additional CO2 at a mean rate of 37 (634) g C m22 yr21 . Therefore, total net CO2 production by P. amurensis averages 55 (651) g C m22 yr21 in an estuarine domain where net primary production consumes only 20 g inorganic C m22 yr21 . CO2 production by P. amurensis in northern San Francisco Bay is an underestimate of the total CO2 supply from the calcified zoobenthic communities of San Francisco Bay, and results from other studies have suggested that this rate is not unusual for temperate estuaries. Global extrapolation yields a gross CO2 production rate in the world’s estuaries of 1 3 1014 g C yr21 , which suggests that calcified benthic organisms in estuaries generate CO2 equal in magnitude to the CO2 emissions from the world’s lakes or from planetary volcanism (the net source is determined by the highly variable rate of CO2 consumption by carbonate dissolution). This biogenic CO2 source is increasing because of the continuing global translocation of mollusks and their successful colonization of new habitats.

  6. Three vibrio-resistance related EST-SSR markers revealed by selective genotyping in the clam Meretrix meretrix.

    Science.gov (United States)

    Nie, Qing; Yue, Xin; Chai, Xueliang; Wang, Hongxia; Liu, Baozhong

    2013-08-01

    The clam Meretrix meretrix is an important commercial bivalve distributed in the coastal areas of South and Southeast Asia. In this study, marker-trait association analyses were performed based on the stock materials of M. meretrix with different vibrio-resistance profile obtained by selective breeding. Forty-eight EST-SSR markers were screened and 27 polymorphic SSRs of them were genotyped in the clam stocks with different resistance to Vibrio parahaemolyticus (11-R and 11-S) and to Vibrio harveyi (09-R and 09-C). Allele frequency distributions of the SSRs among different stocks were compared using Pearson's Chi-square test, and three functional EST-SSR markers (MM959, MM4765 and MM8364) were found to be associated with vibrio-resistance trait. The 140-bp allele of MM959 and 128-bp allele of MM4765 had significantly higher frequencies in resistant groups (11-R and 09-R) than in susceptive/control groups (11-S and 09-C) (P markers were consistent with the three subgroups distinctions. The putative functions of contig959, contig4765 and contig8364 also suggested that the three SSR-involved genes might play important roles in immunity of M. meretrix. All these results supported that EST-SSR markers MM959, MM4765 and MM8364 were associated with vibrio-resistance and would be useful for marker-assisted selection (MAS) in M. meretrix genetic breeding. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Development and validation of 89 novel expressed sequence tag-derived microsatellite markers in blood clam, Tegillarca granosa

    Science.gov (United States)

    Teng, Shuangshuang; Fang, Jun; Cai, Yilong; Chai, Xueliang; Xiao, Guoqiang

    2017-06-01

    Blood clam, Tegillarca granosa, is an important shellfish in Chinese mariculture industry. Investigative research in this species, such as genetic linkage mapping, requires a large panel of molecular markers. In present study, a total of 89 polymorphic microsatellite markers were developed in T. granosa using the sequence database of Life Sciences Technology 454 next generation sequencing technology. All 89 loci were characterized in 20 individual clams from a natural population inhabiting Yueqing Gulf, Zhejiang Province, China. The number of alleles per polymorphic locus varied between 2 and 15, while the observed heterozygosity, expected heterozygosity and polymorphic information content varied between 0.000 and 1.000, 0.102 and 0.921, and 0.048 and 0.886, respectively. Of the 89 loci identified, 32 loci deviated significantly from Hardy-Weinberg equilibrium following Bonferroni correction. Thirty nine markers, which were shown to be polymorphic in a full-sibling family, were tested in Mendelian segregations. As expected, 32 loci were co-dominantly segregated in a Mendelian fashion. These novel developed microsatellite markers represent useful research tools for investigation of population genetic structure and genetic diversity in this species.

  8. Effects of LSP on micro-structures and residual stresses in a 4 mm CLAM steel weld joints

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xizhang, E-mail: chenxizhang@wzu.edu.cn [School of Mechanical and Electrical Engineering, Wenzhou University., Wenzhou 325035 (China); School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China); Fang, Yuanyuan [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China); Zhang, Shuyan; Kelleher, Joe F. [ISIS, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); Zhou, Jianzhong [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China)

    2015-05-15

    The effects of laser shock processing (LSP) on the distribution of residual stress and micro-structure of China Low Activation Martensitic (CLAM) steel weldment were investigated via neutron diffraction and optical microscope (OM). A pair of 4 mm CLAM steel plates joined by GTA welding. Special attention is paid to the generation of high level compressive residual stresses introduced by LSP. Residual stress in longitudinal, normal and transversal direction at weldment surface and longitudinal stress through thickness are evaluated via neutron diffraction. Compressive residual stress after LSP occurred at more than 90% areas within the weld joint, it is almost double the areas of compressive stress compare to weldment surface before LSP. The maximum compressive normal residual stress becomes to −183 MPa after LSP from −63 MPa before LSP. The Modification of surface micro-structures including weld zone (WZ), heat affected zone (HAZ) and base metal (BM) are also discussed. Results to date demonstrate that laser shock processing has been a great potential method for the improvement of mechanical performance of components.

  9. Effects of LSP on micro-structures and residual stresses in a 4 mm CLAM steel weld joints

    International Nuclear Information System (INIS)

    Chen, Xizhang; Fang, Yuanyuan; Zhang, Shuyan; Kelleher, Joe F.; Zhou, Jianzhong

    2015-01-01

    The effects of laser shock processing (LSP) on the distribution of residual stress and micro-structure of China Low Activation Martensitic (CLAM) steel weldment were investigated via neutron diffraction and optical microscope (OM). A pair of 4 mm CLAM steel plates joined by GTA welding. Special attention is paid to the generation of high level compressive residual stresses introduced by LSP. Residual stress in longitudinal, normal and transversal direction at weldment surface and longitudinal stress through thickness are evaluated via neutron diffraction. Compressive residual stress after LSP occurred at more than 90% areas within the weld joint, it is almost double the areas of compressive stress compare to weldment surface before LSP. The maximum compressive normal residual stress becomes to −183 MPa after LSP from −63 MPa before LSP. The Modification of surface micro-structures including weld zone (WZ), heat affected zone (HAZ) and base metal (BM) are also discussed. Results to date demonstrate that laser shock processing has been a great potential method for the improvement of mechanical performance of components

  10. Biomonitoring approach with mussel Mytilus galloprovincialis (Lmk) and clam Ruditapes philippinarum (Adams and Reeve, 1850) in the Lagoon of Venice.

    Science.gov (United States)

    Moschino, Vanessa; Delaney, Eugenia; Meneghetti, Francesca; Ros, Luisa Da

    2011-06-01

    Transplanted Mytilus galloprovincialis and native Ruditapes philippinarum were deployed in 10 sampling stations with different pollution impact within the Lagoon of Venice to evaluate the temporal variations and the suitability of the following cytochemical and histochemical biomarkers just as indicators of environmental stress: lysosomal membrane stability, lipofuscins, neutral lipids and lysosome to cytoplasm volume ratio. The physiological status of the organisms was also investigated by determining the survival in air capability and the reburrowing rate (clams). The biological parameters were assessed in June and October. Furthermore, for a better definition of the environmental aspects of the study sites, heavy metal, PAH and PCB concentrations were also evaluated in the sediments. As a whole, the biological responses examined in both species from all the sampling sites showed significant differences between the two seasonal campaigns, only lysosomal membrane stability exhibited less variability. Pollutants in sediments generally showed low-intermediate contamination levels, few hotspots persisting mostly in the inner areas of the lagoon, the most influenced by the industrial zone. Transplanted mussels were more responsive than native clams and the biological responses of both species varied temporally. The range of the spatial variability was always narrow and reflected only partially the broader variability shown by the chemical content in the sediments. In this sense, biological responses seemed to be particularly influenced by the high temporal and spatial heterogeneity that characterise the Lagoon of Venice, as well as most of the transitional environments.

  11. Consequences of an uncertain mass mortality regime triggered by climate variability on giant clam population management in the Pacific Ocean.

    Science.gov (United States)

    Van Wynsberge, Simon; Andréfouët, Serge; Gaertner-Mazouni, Nabila; Remoissenet, Georges

    2018-02-01

    Despite actions to manage sustainably tropical Pacific Ocean reef fisheries, managers have faced failures and frustrations because of unpredicted mass mortality events triggered by climate variability. The consequences of these events on the long-term population dynamics of living resources need to be better understood for better management decisions. Here, we use a giant clam (Tridacna maxima) spatially explicit population model to compare the efficiency of several management strategies under various scenarios of natural mortality, including mass mortality due to climatic anomalies. The model was parameterized by in situ estimations of growth and mortality and fishing effort, and was validated by historical and new in situ surveys of giant clam stocks in two French Polynesia lagoons. Projections on the long run (100 years) suggested that the best management strategy was a decrease of fishing pressure through quota implementation, regardless of the mortality regime considered. In contrast, increasing the minimum legal size of catch and closing areas to fishing were less efficient. When high mortality occurred due to climate variability, the efficiency of all management scenarios decreased markedly. Simulating El Niño Southern Oscillation event by adding temporal autocorrelation in natural mortality rates increased the natural variability of stocks, and also decreased the efficiency of management. These results highlight the difficulties that managers in small Pacific islands can expect in the future in the face of global warming, climate anomalies and new mass mortalities. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. The influence of salinity on toxicological effects of arsenic in digestive gland of clam Ruditapes philippinarum using metabolomics

    Science.gov (United States)

    Ji, Chenglong; Wu, Huifeng; Liu, Xiaoli; Zhao, Jianmin; Yu, Junbao; Yin, Xiuli

    2013-03-01

    Ruditapes philippinarum, a clam that thrives in intertidal zones of various salinities, is a useful biomonitor to marine contaminants. We investigated the influence of dilution to 75% and 50% of normal seawater salinity (31.1) on the responses of the digestive gland of R. philippinarum to arsenic exposure (20 μg/L), using nuclear magnetic resonance (NMR)-based metabolomics. After acute arsenic exposure for 48 h, salinity-dependent differential metabolic responses were detected. In normal seawater, arsenic exposure increased the concentrations of branched-chain amino acids, and of threonine, proline, phosphocholine and adenosine, and it decreased the levels of alanine, hypotaurine, glucose, glycogen and ATP in the digestive glands. Differential changes in metabolic biomarkers observed at lower salinity (˜23.3) included elevation of succinate, taurine and ATP, and depletion of branched-chain amino acids, threonine and glutamine. Unique effects of arsenic at the lowest salinity (˜15.6) included down-regulation of glutamate, succinate and ADP, and up-regulation of phosphocholine. We conclude that salinity influences the metabolic responses of this clam to arsenic.

  13. Histopathological survey of the mussel Mytilus chilensis (Mytilidae and the clam Gari solida (Psammobiidae from southern Chile

    Directory of Open Access Journals (Sweden)

    Florencia Cremonte

    2015-03-01

    Full Text Available A total of 175 specimens of mussels, Mytilus chilensis (Mytilidae, and 56 specimens of clams, Gari solida (Psammobiidae, were collected in natural beds and culture sites of southern Chile. Juvenile mussel specimens (3 cm of maximum length were free of parasites and diseases, whilst the commercial sized populations was parasitized by intracellular inclusions of bacteria-like organisms in the digestive gland epithelium and in the gills, by ciliates in the gills, turbellarians similar to Paravortex (Rhabocoela in the intestine lumen and copepods attached to the gills. In addition, the disseminated neoplasia disease was also present although in low prevalences. In the clam, G. solida, prokariotic inclusions were found in the digestive gland epithelium and bacteria-like organisms in the gills, often encapsulated by haemocytes; oocysts containing up to 8 sporozoites similar to Nematopsis (Apicomplexa in the connective tissue, causing haemocytic infiltration when the intensity of infection was high; ciliates belonging to two different species (one of them similar to Trichodina inhabiting the gills; and a turbellarian similar to Paravortex in the lumen of digestive system without apparent host reaction. The populations of the bivalve species here studied were devoid of serious pathogens.

  14. Linking valve closure behavior and sodium transport mechanism in freshwater clam Corbicula fluminea in response to copper

    Energy Technology Data Exchange (ETDEWEB)

    Liao, C.-M. [Department of Bioenvironmental Systems Engineering, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei, Taiwan 10617 (China)]. E-mail: cmliao@ntu.edu.tw; Lin, C.-M. [Department of Bioenvironmental Systems Engineering, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei, Taiwan 10617 (China); Jou, L.-J. [Department of Bioenvironmental Systems Engineering, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei, Taiwan 10617 (China); Department of Biomechatronic Engineering, National Ilan University, Ilan, Taiwan 260 (China); Chiang, K.-C. [Department of Bioenvironmental Systems Engineering, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei, Taiwan 10617 (China)

    2007-06-15

    The purpose of this study is to develop a mechanistic model to describe a conceptually new 'flux-biological response' approach based on biotic ligand model (BLM) and Michaelis-Menten (M-M) kinetics to allow the linkage between valve closure behavior and sodium (Na) transport mechanism in freshwater clam Corbicula fluminea in response to waterborne copper (Cu). We test the proposed model against published data regarding Na uptake kinetics in rainbow trout and Na uptake profile in C. fluminea, confirming that the predictive model is robust. Here, we show that the predicted M-M maximum Cu internalization flux in C. fluminea is 0.369 {mu}mol g{sup -1} h{sup -1} with a half-saturation affinity constant of 7.87 x 10{sup -3} {mu}M. Dynamics of Na uptake and valve closure daily rhythm driven by external Cu can also be predicted simultaneously. We suggest that this 'Na transport-valve closure behavior' approach might provide the basis of a future design of biomonitoring tool. - A new flux-biological response model can link valve closure and sodium transport mechanisms in freshwater clam in response to copper.

  15. Removal of methyl orange and methylene blue dyes from aqueous solution using lala clam (Orbicularia orbiculata) shell

    Science.gov (United States)

    Eljiedi, Arwa Alseddig Ahmed; Kamari, Azlan

    2017-05-01

    Textile effluents are considered as potential sources of water pollution because they contain toxic dyes. In the present study, lala clam shell was used as an alternative low-cost adsorbent for the removal of two harmful dyes, namely methyl orange (MO) and methylene blue (MB) from aqueous solution. Batch adsorption studies were carried out by varying experimental parameters such as solution pH, initial concentration and adsorbent dosage. The optimum pH values for MO and MB removal were pH 2.0 and pH 8.0, respectively. At an initial MO and MB concentration of 20 mg/L, the maximum removal percentage of MO and MB were 18.9 % and 81.3 %, respectively. The adsorption equilibrium data were correlated with both Langmuir and Freundlich isotherm models. The biomass adsorbent was characterised using Field Emission Scanning Electron Microscope (FESEM) and Fourier Transform Infrared Spectrometer (FTIR). Results from this study suggest that lala clam shell, a fishery waste, can be beneficial for water treatment.

  16. Mussels and clams from the italian fish market. is there a human exposition risk to metals and arsenic?

    Science.gov (United States)

    Chiesa, L M; Ceriani, F; Caligara, M; Di Candia, D; Malandra, R; Panseri, S; Arioli, F

    2018-03-01

    Seafood is associated with many beneficial effects on human health. However, the overall level of contaminants in biota has increased over the last two centuries and seafood is one of the source of oral exposition to contaminants. Therefore, this work aimed to evaluate cadmium, lead, mercury, arsenic, chromium and nickel presence in mussels and clams, from the Italian market, and the associated risk. The samples were from five different FAO areas. Analyses were carried out using inductively-coupled plasms-mass spectrometry. The sample concentrations were below the maximum levels stated by Commission Regulation (EC) 1881/2006, except one mussel sample, which was non-compliant for cadmium (2.13 ± 0.20 mg kg -1 ). For arsenic, nickel and chromium, maximum levels are not stated by the European Union. In this study, arsenic ranged from 1.29 to 13.35 mg kg -1 and nickel ranged from 1, and BMDL 10 for lung bladder and skin cancer in all mussel samples was overcome, in the 100% and 25% of mussel and clam samples, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Conversion of Biowaste Asian Hard Clam (Meretrix lusoria Shells into White-Emitting Phosphors for Use in Neutral White LEDs

    Directory of Open Access Journals (Sweden)

    Tsung-Yuan Chang

    2016-12-01

    Full Text Available The increasing volume and complexity of waste associated with the modern economy poses a serious risk to ecosystems and human health. However, the remanufacturing and recycling of waste into usable products can lead to substantial resource savings. In the present study, clam shell waste was first transformed into pure and well-crystallized single-phase white light-emitting phosphor Ca9Gd(PO47:Eu2+,Mn2+ materials. The phosphor Ca9Gd(PO47:Eu2+,Mn2+ materials were synthesized by the solid-state reaction method and the carbothermic reduction process, and then characterized and analyzed by means of X-ray diffraction (XRD and photoluminescence (PL measurements. The structural and luminescent properties of the phosphors were investigated as well. The PL and quantum efficiency measurements showed that the luminescence properties of clam shell-based phosphors were comparable to that of the chemically derived phosphors. Moreover, white light-emitting diodes were fabricated through the integration of 380 nm chips and single-phase white light-emitting phosphors (Ca0.979Eu0.006Mn0.0159Gd(PO47 into a single package of a white light emitting diode (WLED emitting a neutral white light of 5298 K with color coordinates of (0.337, 0.344.

  18. Influence of different cooling rates on the microstructure of the HAZ and welding CCT diagram of CLAM steel

    International Nuclear Information System (INIS)

    Zheng Shuhui; Wu Qingsheng; Huang Qunying; Liu Shaojun; Han Yangyang

    2011-01-01

    The evolution of microstructure in the weld HAZ (Heat Affected Zone) under welding thermal cycle was simulated by Gleeble-1500. The microstructures and properties of HAZ at different cooling rates were investigated by optical microscopy (OM), scanning electron microscopy (SEM) and microhardness test. The results showed that when the cooling rates ranged from 3600 K/min to 60 K/min, fully martensitic transformations were achieved, and the cooling rates had little influence on the microstructure and microhardness of martensite. The maximum cooling rate to form ferrite was 60 K/min. When the cooling rates ranged from 60 K/min to 1 K/min, the microhardness of the HAZ began to decrease due to the presence of ferrite, and the lath sizes grew up to 0.13-0.15 μm. The critical cooling rate to gain fully ferrite was found to be slower than 1 K/min. The welding CCT diagram of CLAM steel was constructed and it showed that there were ferrite and martensite transformation regions only. The diagram made it possible to predict the microstructures and properties of HAZ and became an important tool to evaluate weldability of CLAM steel.

  19. Invasive zebra mussels (Driessena polymorpha) and Asian clams (Corbicula fluminea) survive gut passage of migratory fish species: implications for dispersal

    Science.gov (United States)

    Gatlin, Michael R.; Shoup, Daniel E.; Long, James M.

    2013-01-01

    The introduction and spread of invasive species is of great concern to natural resource managers in the United States. To effectively control the spread of these species, managers must be aware of the multitude of dispersal methods used by the organisms. We investigated the potential for survival through the gut of a migrating fish (blue catfish, Ictalurus furcatus) as a dispersal mechanism for two invasive bivalves: zebra mussel (Driessena polymorpha) and Asian clam (Corbicula fluminea). Blue catfish (N = 62) were sampled over several months from Sooner Lake, Oklahoma, transported to a laboratory and held in individual tanks for 48 h. All fecal material was collected and inspected for live mussels. Survival was significantly related to water temperature in the lake at the time of collection, with no mussels surviving above 21.1 C°, whereas 12 % of zebra mussels (N = 939) and 39 % of Asian clams (N = 408) consumed in cooler water survived gut passage. This research demonstrates the potential for blue catfish to serve as a dispersal vector for invasive bivalves at low water temperatures.

  20. Identification of Angiotensin I-Converting Enzyme Inhibitory Peptides Derived from Enzymatic Hydrolysates of Razor Clam Sinonovacula constricta

    Directory of Open Access Journals (Sweden)

    Yun Li

    2016-06-01

    Full Text Available Angiotensin I-converting enzyme (ACE inhibitory activity of razor clam hydrolysates produced using five proteases, namely, pepsin, trypsin, alcalase, flavourzyme and proteases from Actinomucor elegans T3 was investigated. Flavourzyme hydrolysate showed the highest level of degree of hydrolysis (DH (45.87% followed by A. elegans T3 proteases hydrolysate (37.84% and alcalase (30.55%. The A. elegans T3 proteases was observed to be more effective in generating small peptides with ACE-inhibitory activity. The 3 kDa membrane permeate of A. elegans T3 proteases hydrolysate showed the highest ACE-inhibitory activity with an IC50 of 0.79 mg/mL. After chromatographic separation by Sephadex G-15 gel filtration and reverse phase-high performance liquid chromatography, the potent fraction was subjected to MALDI/TOF-TOF MS/MS for identification. A novel ACE-inhibitory peptide (VQY was identified exhibiting an IC50 of 9.8 μM. The inhibitory kinetics investigation by Lineweaver-Burk plots demonstrated that the peptide acts as a competitive ACE inhibitor. The razor clam hydrolysate obtained by A. elegans T3 proteases could serve as a source of functional peptides with ACE-inhibitory activity for physiological benefits.

  1. Population density, biomass, and age-class structure of the invasive clam Corbicula fluminea in rivers of the lower San Joaquin River watershed, California

    Science.gov (United States)

    Brown, L.R.; Thompson, J.K.; Higgins, K.; Lucas, L.V.

    2007-01-01

    Corbicula fluminea is well known as an invasive filter-feeding freshwater bivalve with a variety of effects on ecosystem processes. However. C. fluminea has been relatively unstudied in the rivers of the western United States. In June 2003, we sampled C. fluminea at 16 sites in the San Joaquin River watershed of California, which was invaded by C. fluminea in the 1940s. Corbicula fluminea was common in 2 tributaries to the San Joaquin River, reaching densities of 200 clams??m-2, but was rare in the San Joaquin River. Biomass followed a similar pattern. Clams of the same age were shorter in the San Joaquin River than in the tributaries. Distribution of clams was different in the 2 tributaries, but the causes of the difference are unknown. The low density and biomass of clams in the San Joaquin River was likely due to stressful habitat or to water quality, because food was abundant. The success of C. fluminea invasions and subsequent effects on trophic processes likely depends on multiple factors. As C. fluminea continues to expand its range around the world, questions regarding invasion success and effects on ecosystems will become important in a wide array of environmental settings.

  2. Age and growth of the sword razor clam Ensis arcuatus in the Ría de Pontevedra (NW Spain): Influence of environmental parameters

    Science.gov (United States)

    Hernández-Otero, A.; Gaspar, M. B.; Macho, G.; Vázquez, E.

    2014-01-01

    The sword razor clam Ensis arcuatus is the most important commercial species of razor clam in Spain, and its fishery in the Ría de Pontevedra (Galicia, NW Spain) is the most productive. Despite the economic importance of this species, information on its biology is scarce. This study reports shell morphometric relationships, age, and growth rates of E. arcuatus in three fishing beds in the Ría de Pontevedra (Brensa, Bueu and Ons, located in respectively the inner, middle and outer zones of the ria), providing the first estimates of growth parameters for the species in the Iberian Peninsula. Growth was estimated by examination of surface growth rings and internal shell microgrowth patterns (acetate peel technique) that proved to be the most suitable method for growth estimate. Growth of E. arcuatus was slower in Bueu (L∞ = 140.4, k = 0.40) followed by Brensa (L∞ = 151.91, k = 0.40) and Ons (L∞ = 172.7, k = 0.33), and the clams reached commercial size in 1.7, 2.3 and 2.8 years in Ons, Brensa and Bueu, respectively. The differences in growth between sites in relation to environmental parameters are evaluated and the implications for the razor clam fishery are discussed.

  3. Ecotoxicological and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Short-Neck Clam (Paphia undulata) and Contaminated Sediments in Malacca Strait, Malaysia.

    Science.gov (United States)

    Keshavarzifard, Mehrzad; Zakaria, Mohamad Pauzi; Sharifi, Reza

    2017-10-01

    The distribution, sources, and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediment and the edible tissue of short-neck clam (Paphia undulata) from mudflat ecosystem in the west coast of Malaysia were investigated. The concentrations of ∑ 16 PAHs varied from 347.05 to 6207.5 and 179.32 to 1657.5 ng g -1 in sediment and short-neck clam samples, respectively. The calculations of mean PEL quotients (mean-PELQs) showed that the ecological risk of PAHs in the sediment samples was low to moderate-high level, whereas the total health risk through ingestion and dermal contact was considerably high. The PAHs biota sediment accumulation factors data for short-neck clam were obtained in this study, indicating a preferential accumulation of lower molecular weight PAHs. The source apportionment of PAHs in sediment using positive matrix factorization model indicated that the highest contribution to the PAHs was from diesel emissions (30.38%) followed by oil and oil derivate and incomplete coal combustion (23.06%), vehicular emissions (16.43%), wood combustion (15.93%), and natural gas combustion (14.2%). A preliminary evaluation of human health risk using chronic daily intake, hazard index, benzo[a]pyrene-equivalent (BaP eq ) concentration, and the incremental lifetime cancer risk indicated that PAHs in short-neck clam would induce potential carcinogenic effects in the consumers.

  4. Perkinsus olseni and P. chesapeaki detected in a survey of perkinsosis of various clam species in Galicia (NW Spain) using PCR-DGGE as a screening tool.

    Science.gov (United States)

    Ramilo, Andrea; Pintado, José; Villalba, Antonio; Abollo, Elvira

    2016-01-01

    A survey on perkinsosis was performed involving 15 locations scattered along the Galician coast (NW Spain) and four clam species with high market value (Ruditapes decussatus, Ruditapes philippinarum, Venerupis corrugata and Polititapes rhomboides). The prevalence of Perkinsus parasites was estimated by PCR using genus-specific primers. The highest percentage of PCR-positive cases for perkinsosis corresponded to clams R. decussatus and V. corrugata, while lower values were detected in R. philippinarum and no case was found in P. rhomboides. The discrimination of Perkinsus species was performed by PCR-RFLP and by a new PCR-DGGE method developed in this study. Perkinsus olseni was identified in every clam species, except in P. rhomboides, using both PCR-DGGE and PCR-RFLP. Additionally, Perkinsus chesapeaki was only detected by PCR-DGGE infecting two Manila clams R. philippinarum from the same location, reporting the first case in Galicia. P. chesapeaki identification was further confirmed by in situ hybridisation assay and phylogenetic analysis of ITS region and LSU rDNA. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. A study of the naturalisation and dispersal of a non-native bivalve, the Manila clam, Ruditapes philippinarum (Adams and Reeve 1850) in estuaries along the South coast of England.

    OpenAIRE

    Harris, Matthew

    2016-01-01

    The Manila clam, Ruditapes philippinarum, was introduced into the British Isles in the 1980s for the purpose of aquaculture in order to take advantage of the rapid growth rate and high profitability of this non-native species. The decision to import the Manila clam, was based on the findings of a report commissioned by the Ministry of Agriculture Fisheries and Food which determined that the Manila clam would be able to be grown to marketable size faster than the local species Ruditapes decuss...

  6. Do selenium and glutathione (GSH) detoxify mercury in marine invertebrates. Pt. 2. Effect on gill adenosine triphosphatase and related blood factors in an arcid clam Anadara granosa

    Energy Technology Data Exchange (ETDEWEB)

    Patel, B.; Chandy, J.P.

    1987-12-14

    Arcid blood clams Anadara granosa (L.) with erythrocytic haemoglobin were exposed to sublethal concentrations of Hg/sup 2+/ (0.1 mg l/sup -1/, as HgCl/sub 2/), Se/sup 4+/ (1.0 mg l/sup -1/, SeO/sub 2/) and reduced glutathione (GSH, 1.0 mg l/sup -1/), either individually or in combination, for 96 to 144 h in vivo. Parameters studied included gill ATPase, haemoglobin (Hb), haemolymph, haematocrit, protein, free amino acids (FAA) and plasma Na/sup +/, K/sup +/, Ca/sup ++/, Mg/sup ++/ and osmolality. Hg reduced gill ATPase activity by at least 50%. Se alone and Hg+Se also inhibited enzyme activity. No similar changes occured on exposure to GSH alone. GSH in the presence of Hg, on the other hand, completely nullified the inhibitory effect of Hg. In the clams transferred to GSH (for 72 h) after initial exposure to Hg (72 h) and vice versa, enzyme activity was inhibited by 45% compared to controls. Haematocrit increased significantly in clams exposed to Hg alone and to Se alone, but exposure to GSH alone and GSH+Hg had no significant effect. Erythrocyte sedimentation rate (ESR) increased significantly in clams exposed to Se, but was lowered to varying degrees in all other experimental clams. Hb content and haemolymph protein levels in experimental groups did not change significantly compared to controls. Methaemoglobin increased significantly in all experimental groups, the maximum increase (ca 137%) being in those exposed to Hg. Free amino acid (FAA) levels were appreciably raised in clams treated with Hg alone and Hg+Se, but exposure to Se alone and GSH alone had no significant effect. Plasma cations (Na/sup +/, K/sup +/ and Ca/sup ++/) showed significant changes following exposure to Hg. However, in clams exposed to Hg+Se only K/sup +/ and Ca/sup ++/ levels increased. Concentration of Mg/sup ++/ in haemolymph of groups treated with Hg, Se and GSH remained practically unaltered, but in groups exposed to Hg+Se and Hg+GSH it increased appreciably. (Abstract Truncated)

  7. Certification of Trace Elements and Methyl Mercury Mass Fractions in IAEA-461 Clam (Gafrarium tumidum) Sample

    International Nuclear Information System (INIS)

    2016-01-01

    The primary goal of the IAEA Environment Laboratories is to assist Member States in the use of both stable and radioisotope analytical techniques to understand, monitor and protect the environment. In this context, the major impact exerted by large coastal cities on marine ecosystems is an issue of primary concern for the IAEA and the IAEA Environment Laboratories. The marine pollution assessments required to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. The IAEA Environment Laboratories has been assisting national laboratories and regional laboratory networks since the early 1970s through the provision of reference material programme for the analysis of radionuclides, trace elements and organic compounds in marine samples. Quality assurance, quality control and associated good laboratory practice are essential components of all marine environmental monitoring studies. Quality control procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess the reliability and comparability of measurement data. Data that are not based on adequate quality assurance and quality control can be erroneous, and their misuse can lead to poor environmental management decisions. This publication describes the production of the IAEA-461 certified reference material, which was produced following ISO Guide 34:2009, General Requirements for the Competence of Reference Material Producers. A sample of approximately 60 kg of clams (Gafrarium tumidum) was collected in Noumea, New Caledonia, and processed at the IAEA Environment Laboratories to produce a certified reference material of marine biota. The sample contained certified mass fractions for arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, mercury, methyl mercury, manganese, nickel, selenium, vanadium and zinc. The produced vials

  8. Phylogeny and androgenesis in the invasive Corbicula clams (Bivalvia, Corbiculidae in Western Europe

    Directory of Open Access Journals (Sweden)

    Descy Jean-Pierre

    2011-05-01

    Full Text Available Abstract Background The genus Corbicula is one of the most invasive groups of molluscs. It includes both sexual and androgenetic lineages. The present study re-assessed the different morphotypes and haplotypes of West European Corbicula in order to clarify their taxonomic identification and phylogenetic relationships with American and Asian Corbicula clams. We studied several populations from West European river basins (Meuse, Seine, Rhine and Rhône through an "integrative taxonomy" approach. We combined morphology, partial mitochondrial COI and cyt b sequences and eleven microsatellite loci. Furthermore, we looked for discrepancies between mtDNA and nrDNA/morphology, indicative of androgenesis between lineages. Results There are three Corbicula morphotypes in Western Europe associated to three mitochondrial lineages and three genotypes. Form R shares the same COI haplotype as the American form A and the Japanese C. leana. Form S and the American form C have the same haplotype, although their morphologies seem divergent. The European form Rlc belongs to the same mitochondrial lineage as both the American form B and the Asian C. fluminea. Interestingly, within each haplotype/genotype or lineage, no genetic diversity was found although their invasive success is high. Moreover, we detected rare mismatches between mtDNA and nrDNA/morphology, indicative of androgenesis and mitochondrial capture between form R and form S and therefore challenging the phylogenetic relatedness and the species status within this genus. The global phylogenetic analysis revealed that the sexual Corbicula lineages seem restricted to the native areas while their androgenetic relatives are widespread and highly invasive. Conclusions We clarified the discrepancies and incongruent results found in the literature about the European morphotypes of Corbicula and associated mitochondrial lineages. The three West European morphotypes belong to three distinct nuclear and

  9. Evaluation of the MODIS Aerosol Retrievals over Ocean and Land during CLAMS.

    Science.gov (United States)

    Levy, R. C.; Remer, L. A.; Martins, J. V.; Kaufman, Y. J.; Plana-Fattori, A.; Redemann, J.; Wenny, B.

    2005-04-01

    The Chesapeake Lighthouse Aircraft Measurements for Satellites (CLAMS) experiment took place from 10 July to 2 August 2001 in a combined ocean-land region that included the Chesapeake Lighthouse [Clouds and the Earth's Radiant Energy System (CERES) Ocean Validation Experiment (COVE)] and the Wallops Flight Facility (WFF), both along coastal Virginia. This experiment was designed mainly for validating instruments and algorithms aboard the Terra satellite platform, including the Moderate Resolution Imaging Spectroradiometer (MODIS). Over the ocean, MODIS retrieved aerosol optical depths (AODs) at seven wavelengths and an estimate of the aerosol size distribution. Over the land, MODIS retrieved AOD at three wavelengths plus qualitative estimates of the aerosol size. Temporally coincident measurements of aerosol properties were made with a variety of sun photometers from ground sites and airborne sites just above the surface. The set of sun photometers provided unprecedented spectral coverage from visible (VIS) to the solar near-infrared (NIR) and infrared (IR) wavelengths. In this study, AOD and aerosol size retrieved from MODIS is compared with similar measurements from the sun photometers. Over the nearby ocean, the MODIS AOD in the VIS and NIR correlated well with sun-photometer measurements, nearly fitting a one-to-one line on a scatterplot. As one moves from ocean to land, there is a pronounced discontinuity of the MODIS AOD, where MODIS compares poorly to the sun-photometer measurements. Especially in the blue wavelength, MODIS AOD is too high in clean aerosol conditions and too low under larger aerosol loadings. Using the Second Simulation of the Satellite Signal in the Solar Spectrum (6S) radiative code to perform atmospheric correction, the authors find inconsistency in the surface albedo assumptions used by the MODIS lookup tables. It is demonstrated how the high bias at low aerosol loadings can be corrected. By using updated urban/industrial aerosol

  10. Phylogeny and androgenesis in the invasive Corbicula clams (Bivalvia, Corbiculidae) in Western Europe

    Science.gov (United States)

    2011-01-01

    Background The genus Corbicula is one of the most invasive groups of molluscs. It includes both sexual and androgenetic lineages. The present study re-assessed the different morphotypes and haplotypes of West European Corbicula in order to clarify their taxonomic identification and phylogenetic relationships with American and Asian Corbicula clams. We studied several populations from West European river basins (Meuse, Seine, Rhine and Rhône) through an "integrative taxonomy" approach. We combined morphology, partial mitochondrial COI and cyt b sequences and eleven microsatellite loci. Furthermore, we looked for discrepancies between mtDNA and nrDNA/morphology, indicative of androgenesis between lineages. Results There are three Corbicula morphotypes in Western Europe associated to three mitochondrial lineages and three genotypes. Form R shares the same COI haplotype as the American form A and the Japanese C. leana. Form S and the American form C have the same haplotype, although their morphologies seem divergent. The European form Rlc belongs to the same mitochondrial lineage as both the American form B and the Asian C. fluminea. Interestingly, within each haplotype/genotype or lineage, no genetic diversity was found although their invasive success is high. Moreover, we detected rare mismatches between mtDNA and nrDNA/morphology, indicative of androgenesis and mitochondrial capture between form R and form S and therefore challenging the phylogenetic relatedness and the species status within this genus. The global phylogenetic analysis revealed that the sexual Corbicula lineages seem restricted to the native areas while their androgenetic relatives are widespread and highly invasive. Conclusions We clarified the discrepancies and incongruent results found in the literature about the European morphotypes of Corbicula and associated mitochondrial lineages. The three West European morphotypes belong to three distinct nuclear and mitochondrial lineages. However

  11. Advances in the representation of stratospheric transport by the Brewer-Dobson circulation by use of Lagrangian modelling with CLaMS

    Science.gov (United States)

    Ploeger, Felix; Konopka, Paul; Diallo, Mohamadou; Birner, Thomas; Hoppe, Charlotte; Müller, Rolf; Haenel, Florian; Stiller, Gabriele; Poshyvailo, Liubov; Garny, Hella; Dietmüller, Simone; Jöckel, Patrick; Engel, Andreas; Boenisch, Harald

    2017-04-01

    The global stratospheric Brewer-Dobson circulation (BDC) is expected to accelerate with rising Greenhouse gas concentrations, in turn changing the stratospheric trace gas composition and providing an important feedback via radiation on climate change. However, trends in the BDC are largely uncertain, with current climate model results disagreeing with existing observations of mean age of air, the average transit time for an air parcel since entering the stratosphere. We present advances in representing stratospheric trace gas transport caused by the Brewer-Dobson circulation by using the Chemical Lagrangian model of the Stratosphere (CLaMS), a global Lagrangian chemistry transport model with a physically-based parameterization of small-scale mixing. Mean age simulated with CLaMS driven by reanalysis meteorology agrees well with satellite and in-situ observations. Regarding the inter-annual and decadal changes, like increasing age in the Northern hemisphere and decreasing age in the Southern hemisphere during 2002-2012, the natural variability (e.g., QBO, ENSO, volcanic aerosols) is found to play a key role. Age of air spectra simulated with CLaMS provide further insights into the processes involved. Our analysis reveals a crucial effect of mixing on mean age and its decadal change pattern, suggesting that differences between climate models and observations likely involve differences in the effect of mixing. This progress in modelling stratospheric transport has recently been transferred to climate modelling by coupling the Lagrangian transport scheme CLaMS into the global atmosphere-chemistry model EMAC. First results show improvements of stratospheric transport compared to the standard flux-form semi-Lagrangian transport scheme. These improvements are found particularly in regions of strong transport barriers like the polar vortex, with Lagrangian CLaMS transport resulting in a stronger and more realistic transport barrier.

  12. Recruitment of mud clam Polymesoda erosa (Solander, 1876 in a mangrove habitat of Chorao island, Goa

    Directory of Open Access Journals (Sweden)

    Sandhya Clemente

    2011-06-01

    Full Text Available Habitat-specific settlement success results either from active habitat selection or differential mortality after non-selective settlement. The mud clam Polymesoda erosa (Solander, 1876 is an ecologically and economically important benthic invertebrate with high abundance in the mangrove forests of Chorao Island, Goa, India. A one-year study (Jul 2004-Jul 2005 was conducted to characterize the patterns of post-larval settlement and survival of P. erosa in the mangrove habitat. The mean density of settling post-larvae was 28 no.m-2 with a majority of settlers during Sept 04. The density of adult clams in the landward zone ranged from 7-12 no.m-2 (mean: 9 ± 6 sd; n=122. In the seaward region, adults were completely absent at the low tide level. Higher densities of juveniles observed at the low- and mid-tide levels were assumed to be due to frequent inundation which allowed the young individuals to feed adequately and attain the critical sizes at which vulnerability to physical and biological constraints is substantially reduced, whereas, at high-tide level, increased desiccation may account for the mortality of settlers. It is speculated that initially the settlers settle according to the hydrodynamic conditions for sedimentation; however, adult survival is affected by their recruitment in a suitable habitat (e.g. substrates near Avicennia sp.. Thus, habitat dependent viability during the post-settlement phase could be the best explanation for the non-random, patchy distribution of P. erosa observed in the Chorao mangrove swamp.Um assentamento larval bem sucedido resulta da seleção ativa do habitat pelas larvas ou da mortalidade diferencial destas após o assentamento não seletivo. Nos manguezais da ilha Chorao, Goa, India, a ostra do lodo Polymesoda erosa (Solander, 1876 é um invertebrado muito abundante e de importância econômica. O presente trabalho, realizado durante um ano (julho de 2004 a julho de 2005, visou caracterizar os padr

  13. Following the infection process of vibriosis in Manila clam (Ruditapes philippinarum) larvae through GFP-tagged pathogenic Vibrio species.

    Science.gov (United States)

    Dubert, Javier; Nelson, David R; Spinard, Edward J; Kessner, Linda; Gomez-Chiarri, Marta; da Costa, Fiz; Prado, Susana; Barja, Juan L

    2016-01-01

    Vibriosis represents the main bottleneck for the larval production process in shellfish aquaculture. While the signs of this disease in bivalve larvae are well known, the infection process by pathogenic Vibrio spp. during episodes of vibriosis has not been elucidated. To investigate the infection process in bivalves, the pathogens of larvae as V. tubiashii subsp. europaensis, V. neptunius and V. bivalvicida were tagged with green fluorescent protein (GFP). Larvae of Manila clam (Ruditapes philippinarum) were inoculated with the GFP-labeled pathogens in different infection assays and monitored by microscopy. Manila clam larvae infected by distinct GFP-tagged Vibrio spp. in different challenges showed the same progression in the infection process, defining three infection stages. GFP-tagged Vibrio spp. were filtered by the larvae through the vellum and entered in the digestive system through the esophagus and stomach and colonized the digestive gland and particularly the intestine, where they proliferated during the first 2h of contact (Stage I), suggesting a chemotactic response. Then, GFP-tagged Vibrio spp. expanded rapidly to the surrounding organs in the body cavity from the dorsal to ventral region (Stage II; 6-8h), colonizing the larvae completely at the peak of infection (Stage III) (14-24h). Results demonstrated for the first time that the vibriosis is asymptomatic in Manila clam larvae during the early infection stages. Thus, the early colonization and the rapid proliferation of Vibrio pathogens within the body cavity supported the sudden and fatal effect of the vibriosis, since the larvae exhibited the first signs of disease when the infection process is advanced. As a first step in the elucidation of the potential mechanisms of bacterial pathogenesis in bivalve larvae the enzymatic activities of the extracellular products released from the wild type V. neptunius, V. tubiashii subsp. europaensis and V. bivalvicida were determined and their cytotoxicity was

  14. The Effect of Varied Concentration Tamarind (Tamarindus Indica L) Extract and the Soaking TIME on the Reduction Level of Heavy Metals Plumbum (Pb) and Cadmium (Cd) in the Clam (Anadara Granosa) Blood

    OpenAIRE

    Edina, Lydia Mia; ', Sumarto; ', Edison

    2017-01-01

    This research aimed to determine the optimum concentration of tamarind extract and soaking time to reduce the heavy metals Pb and Cd in the blood of clam (Anadara granosa). The research was used the experimental method and designed as Factorial Completely Randomized Design. The clam was soaked into the solution of tamarind extract at 4 level concentrations, namely: without extract tamarind (K0), 10% tamarind (K10), 15% tamarind (K15), and 20% tamarind (K20), combined to 3 varied soaking time,...

  15. The tertiary structure of an i-type lysozyme isolated from the common orient clam (Meretrix lusoria).

    Science.gov (United States)

    Kuwano, Yuko; Yoneda, Kazunari; Kawaguchi, Yuya; Araki, Tomohiro

    2013-11-01

    To evaluate the structure-function relationships of invertebrate lysozymes, a new invertebrate-type (i-type) lysozyme was isolated from the common orient clam (Meretrix lusoria) and the tertiary structure of this enzyme was determined. Comparison of the tertiary structure of this enzyme with those of chicken and Venerupi philippinarum lysozymes revealed that the location of the side chain of the second catalytic residue, an aspartic acid, and the N-acetylglucosamine trimer bound at subsites A-C were different. Furthermore, the amino acid electrostatically interacting with Asp30 in V. philippinarum lysozyme, Lys108, was substituted by Gly in M. lusoria lysozyme and no other possible amino acid that could contribute to this interaction was found in M. lusoria lysozyme. It therefore seems that the substitutions of the amino acids at the interface of the V. philippinarum lysozyme dimer are likely to change the oligomeric state of the M. lusoria lysozyme.

  16. Purification and partial characterization of a N-glycolylneuraminic acid specific lectin from the clam Anadara granosa (L).

    Science.gov (United States)

    Dam, T K; Sarkar, M; Ghosal, J; Choudhury, A

    1993-10-15

    The N-glycolylneuraminic acid-specific lectin (AFL) from the foot muscles of the marine clam Anadara granosa has been purified to homogeneity by affinity chromatography on bovine submaxillary mucin-Sepharose 4B. The Ca(2+)-dependent lectin agglutinates rabbit erythrocytes. The purified lectin is a tetrameric protein of native M(r) 254 kDa having a pI value of 6.65. The M(r) of two subunits is 65 kDa each and that of the remaining two is 62 kDa each. The dominant amino acids of the lectin are aspartic acid, glutamic acid, serine and glycine. The lectin activity is inhibited only by N-glycolylneuraminic acid specially when it is present in the macromolecular structure of mucin viz., porcine submaxillary mucin, which is the most potent inhibitor. The binding site does not recognize N-acetylneuraminic acid. Due to this strict specificity, the lectin appears to be unique.

  17. Composition and dynamics of the nucleolinus, a link between the nucleolus and cell division apparatus in surf clam (Spisula) oocytes.

    Science.gov (United States)

    Alliegro, Mark C; Hartson, Steven; Alliegro, Mary Anne

    2012-02-24

    The nucleolinus is a little-known cellular structure, discovered over 150 years ago (Agassiz, L. (1857) Contributions to the Natural History of the United States of America, First Monograph, Part IIL, Little, Brown and Co., Boston) and thought by some investigators in the late 19th to mid-20th century to function in the formation of the centrosomes or spindle. A role for the nucleolinus in formation of the cell division apparatus has recently been confirmed in oocytes of the surf clam, Spisula solidissima (Alliegro, M. A., Henry, J. J., and Alliegro, M. C. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 13718-13723). However, we know so little about the composition and dynamics of this compartment, it is difficult to construct mechanistic hypotheses or even to be sure that prior reports were describing analogous structures in the cells of mammals, amphibians, plants, and other organisms where it was observed. Surf clam oocytes are an attractive model to approach this problem because the nucleolinus is easily visible by light microscopy, making it accessible by laser microsurgery as well as isolation by common cell fractionation techniques. In this report, we analyze the macromolecular composition of isolated Spisula nucleolini and examine the relationship of this structure to the nucleolus and cell division apparatus. Analysis of nucleolinar RNA and protein revealed a set of molecules that overlaps with but is nevertheless distinct from the nucleolus. The proteins identified were primarily ones involved in nucleic acid metabolism and cell cycle regulation. Monoclonal antibodies generated against isolated nucleolini revealed centrosomal forerunners in the oocyte cytoplasm. Finally, induction of damage to the nucleolinus by laser microsurgery altered the trafficking of α- and γ-tubulin after fertilization. These observations strongly support a role for the nucleolinus in cell division and represent our first clues regarding mechanism.

  18. Northern Marshall Islands radiological survey: radionuclide concentrations in fish and clams and estimated doses via the marine pathway

    International Nuclear Information System (INIS)

    Robison, W.L.; Noshkin, V.E.; Phillips, W.A.; Eagle, R.J.

    1981-01-01

    The survey consisted, in part, of an aerial radiological reconnaissance to map the external gamma-ray exposure rates. As a secondary phase, terrestrial and marine samples were collected to assess the radiological dose from pertinent food chains to atoll inhabitants. The marine sample collection, processing, and dose assessment methodology are presented as well as the concentration data for 90 Sr, 137 Cs, 238 Pu, 239+240 Pu, 241 Am, and any of the other gamma emitters in fish and clam muscle tissue from the different species collected. Doses are calculated from the average radionuclide concentrations in fish and clam muscle tissue assuming an average daily intake of 200 and 10 g, respectivelty. The 90 Sr concentration in muscle tissue is very low and there is little difference in the average concentrations from the different fish from different atolls or islands. The 239+240 Pu concentration in the muscle tissue of all reef species, however, is higher than that in pelagic lagoon fish. In contrast, 137 Cs concentrations are lowest in the muscle tissue of the bottom-feeding reef species and highest in pelagic logoon fish. Recent measurements of radionuclide concentrations in fish muscle tissue and other marine dietary items from international sources show that the average concentrations in species from the Marshall Islands are comparable to those in fish typically consumed as food in the United States and are generally lower than those in most international marine dietary items. The whole-body dose rates based on continuous consumption of 200 g/d of fish range from 0.028 to 0.1 mrem/y; the bone-marrow dose rates range from 0.029 to 0.12 mrem/y. The dose commitment, or 30-y integral doses, range from 0.00063 to 0.0022 rem for the whole body and from 0.00065 to 0.0032 rem for the bone marrow

  19. Toxicological responses of the hard clam Meretrix meretrix exposed to excess dissolved iron or challenged by Vibrio parahaemolyticus

    International Nuclear Information System (INIS)

    Zhou, Qing; Zhang, Yong; Peng, Hui-Fang; Ke, Cai-Huan; Huang, He-Qing

    2014-01-01

    Highlights: • Fe accumulated in hepatopancreas tissues after iron-enriched exposure. • Ferritin expression was positively correlated with iron concentration in seawater. • Ferritin appears to be involved in iron homeostasis and immune defense mechanism of M. meretrix. • mRNAs of cytokine genes responded faster than antioxidant enzyme genes in immune defense mechanism. • The study gives a new potential biomarker for monitoring iron levels in seawater. - Abstract: The responses of genes encoding defense components such as ferritin, the lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF), the inhibitor of nuclear factor-κB (IκB), metallothionein, and glutathione peroxidase were assessed at the transcriptional level in order to investigate the toxicological and immune mechanism of the hard clam Meretrix meretrix (HCMM) following challenge with iron or a bacterium (Vibrio parahaemolyticus). Fe dissolved in natural seawater led to an increase of Fe content in both the hepatopancreas and gill tissue of HCMM between 4 and 15 days of exposure. The ferritin gene responded both transcriptionally as indicated by real-time quantitative PCR and translationally as shown by western blotting results to iron exposure and both transcriptional and translational ferritin expression in the hepatopancreas had a positive correlation with the concentration of dissolved iron in seawater. Both iron and V. parahaemolyticus exposure triggered immune responses with similar trends in clam tissues. There was a significant post-challenge mRNA expression of LITAF and IκB at 3 h, ferritin at 24 h, and metallothionein and glutathione peroxidase at 48 h. This behavior might be linked to their specific functions in physiological processes. These results suggested that similar signaling pathways were triggered during both iron and V. parahaemolyticus challenges. Here, we indicated that the ferritin of Meretrix meretrix was an intermediate in the pathway of iron homeostasis

  20. Persistent organic pollutants (POPs) in populations of the clam Chione californiensis in coastal lagoons of the Gulf of California.

    Science.gov (United States)

    Vargas-González, Héctor H; Méndez-Rodríguez, Lía C; García-Hernández, Jaqueline; Mendoza-Salgado, Renato A; Zenteno-Savín, Tania; Arreola-Lizárraga, José A

    2016-07-02

    This study examines the potential public health risk due to the massive use of organochlorine pesticides (OCs) in agriculture in the Gulf of California. Specimens of the clam Chione californiensis were collected from three coastal lagoons (Yavaros, Altata and Reforma). Sites were classified as polluted/nonpolluted based on the presence/absence of OCs as an indicator of the persistence of these pollutants; in polluted sites, the time elapsed since pesticide application (past or recent) was estimated. Screening values (SV) for protecting human health as per the U.S. Environmental Protection Agency (EPA) were used for risk assessment. OCs detected were ranked according to frequency of occurrence as follows: γ-chlordane (75%) > endrin (54%) > aldrin (48%) > heptachlor, and dichlorodiphenyl-trichloroethane (DDE) (37%) > β-heptachlor epoxide (30%) > lindane (α-BHC, δ-BHC) and endosulphan I (≤ 6%). Specifically, OCs detected at the highest concentration were heptachlor in Yavaros (0.0168 µgg(-1)) and Altata (0.0046 µgg(-1)), and aldrin in Reforma (0.0019 µgg(-1)). β-Heptachlor epoxide in Altata and Reforma was the only OC with a concentration exceeding the EPA Screening Value. From our results and based on the monthly consumption limit set forth by EPA, the maximum safe consumption of clams to avoid a carcinogenic risk derived from β-heptachlor epoxide in the fishing villages of Yavaros and Altata is 4 servings per month (1 serving = 0.227 kg) by a 70-kg person. These findings suggest that concentrations of OCs and their isomers in C. californiensis populations reflect environmental persistence as well as recent inputs of OCs into coastal lagoons in the Gulf of California.

  1. Sequencing and de novo assembly of the Asian clam (Corbicula fluminea) transcriptome using the Illumina GAIIx method.

    Science.gov (United States)

    Chen, Huihui; Zha, Jinmiao; Liang, Xuefang; Bu, Jihong; Wang, Miao; Wang, Zijian

    2013-01-01

    The Asian clam (Corbicula fluminea) is currently one of the most economically important aquatic species in China and has been used as a test organism in many environmental studies. However, the lack of genomic resources, such as sequenced genome, expressed sequence tags (ESTs) and transcriptome sequences has hindered the research on C. fluminea. Recent advances in large-scale RNA-Seq enable generation of genomic resources in a short time, and provide large expression datasets for functional genomic analysis. We used a next-generation high-throughput DNA sequencing technique with an Illumina GAIIx method to analyze the transcriptome from the whole bodies of C. fluminea. More than 62,250,336 high-quality reads were generated based on the raw data, and 134,684 unigenes with a mean length of 791 bp were assembled using the Velvet and Oases software. All of the assembly unigenes were annotated by running BLASTx and BLASTn similarity searches on the Nt, Nr, Swiss-Prot, COG and KEGG databases. In addition, the Clusters of Orthologous Groups (COGs), Gene Ontology (GO) terms and Kyoto Encyclopedia of Gene and Genome (KEGG) annotations were also assigned to each unigene transcript. To provide a preliminary verification of the assembly and annotation results, and search for potential environmental pollution biomarkers, 15 functional genes (five antioxidase genes, two cytochrome P450 genes, three GABA receptor-related genes and five heat shock protein genes) were cloned and identified. Expressions of the 15 selected genes following fluoxetine exposure confirmed that the genes are indeed linked to environmental stress. The C. fluminea transcriptome advances the underlying molecular understanding of this freshwater clam, provides a basis for further exploration of C. fluminea as an environmental test organism and promotes further studies on other bivalve organisms.

  2. Sequencing and de novo assembly of the Asian clam (Corbicula fluminea transcriptome using the Illumina GAIIx method.

    Directory of Open Access Journals (Sweden)

    Huihui Chen

    Full Text Available BACKGROUND: The Asian clam (Corbicula fluminea is currently one of the most economically important aquatic species in China and has been used as a test organism in many environmental studies. However, the lack of genomic resources, such as sequenced genome, expressed sequence tags (ESTs and transcriptome sequences has hindered the research on C. fluminea. Recent advances in large-scale RNA-Seq enable generation of genomic resources in a short time, and provide large expression datasets for functional genomic analysis. METHODOLOGY/PRINCIPAL FINDINGS: We used a next-generation high-throughput DNA sequencing technique with an Illumina GAIIx method to analyze the transcriptome from the whole bodies of C. fluminea. More than 62,250,336 high-quality reads were generated based on the raw data, and 134,684 unigenes with a mean length of 791 bp were assembled using the Velvet and Oases software. All of the assembly unigenes were annotated by running BLASTx and BLASTn similarity searches on the Nt, Nr, Swiss-Prot, COG and KEGG databases. In addition, the Clusters of Orthologous Groups (COGs, Gene Ontology (GO terms and Kyoto Encyclopedia of Gene and Genome (KEGG annotations were also assigned to each unigene transcript. To provide a preliminary verification of the assembly and annotation results, and search for potential environmental pollution biomarkers, 15 functional genes (five antioxidase genes, two cytochrome P450 genes, three GABA receptor-related genes and five heat shock protein genes were cloned and identified. Expressions of the 15 selected genes following fluoxetine exposure confirmed that the genes are indeed linked to environmental stress. CONCLUSIONS/SIGNIFICANCE: The C. fluminea transcriptome advances the underlying molecular understanding of this freshwater clam, provides a basis for further exploration of C. fluminea as an environmental test organism and promotes further studies on other bivalve organisms.

  3. Toxicological responses of the hard clam Meretrix meretrix exposed to excess dissolved iron or challenged by Vibrio parahaemolyticus

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Qing [State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102 (China); State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102 (China); Zhang, Yong [Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory of Chemical Biology of Fujian Province, Xiamen University, Xiamen 361102 (China); Peng, Hui-Fang [State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102 (China); Ke, Cai-Huan, E-mail: chke@xmu.edu.cn [State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102 (China); Huang, He-Qing, E-mail: hqhuang@xmu.edu.cn [State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102 (China); State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102 (China); Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory of Chemical Biology of Fujian Province, Xiamen University, Xiamen 361102 (China)

    2014-11-15

    Highlights: • Fe accumulated in hepatopancreas tissues after iron-enriched exposure. • Ferritin expression was positively correlated with iron concentration in seawater. • Ferritin appears to be involved in iron homeostasis and immune defense mechanism of M. meretrix. • mRNAs of cytokine genes responded faster than antioxidant enzyme genes in immune defense mechanism. • The study gives a new potential biomarker for monitoring iron levels in seawater. - Abstract: The responses of genes encoding defense components such as ferritin, the lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF), the inhibitor of nuclear factor-κB (IκB), metallothionein, and glutathione peroxidase were assessed at the transcriptional level in order to investigate the toxicological and immune mechanism of the hard clam Meretrix meretrix (HCMM) following challenge with iron or a bacterium (Vibrio parahaemolyticus). Fe dissolved in natural seawater led to an increase of Fe content in both the hepatopancreas and gill tissue of HCMM between 4 and 15 days of exposure. The ferritin gene responded both transcriptionally as indicated by real-time quantitative PCR and translationally as shown by western blotting results to iron exposure and both transcriptional and translational ferritin expression in the hepatopancreas had a positive correlation with the concentration of dissolved iron in seawater. Both iron and V. parahaemolyticus exposure triggered immune responses with similar trends in clam tissues. There was a significant post-challenge mRNA expression of LITAF and IκB at 3 h, ferritin at 24 h, and metallothionein and glutathione peroxidase at 48 h. This behavior might be linked to their specific functions in physiological processes. These results suggested that similar signaling pathways were triggered during both iron and V. parahaemolyticus challenges. Here, we indicated that the ferritin of Meretrix meretrix was an intermediate in the pathway of iron homeostasis

  4. Metals bioaccumulation and biomarkers responses in the Neotropical freshwater clam Anodontites trapesialis: Implications for monitoring coal mining areas.

    Science.gov (United States)

    Oliveira, Luciana Fernandes de; Cabral, Millena Terezinha; Vieira, Carlos Eduardo Delfino; Antoniazzi, Matheus Henrique; Risso, Wagner Ezequiel; Martinez, Claudia Bueno Dos Reis

    2016-11-15

    As one of the most impactful industries, coal mining can promote several alterations at surrounding environment. In surface water, elevated concentrations of metals like Mn, Zn, Fe and Al are often observed. Thus, the aim of this study was to investigate the bioaccumulation and the sub-lethal effects of these metals on various organs of the Neotropical bivalve Anodontites trapesialis confined along a stream located near a coal mine, in order to assess a set of biomarkers that could be used for effectively monitoring coal mining areas. Clams were caged, for 96h, at two sites located upstream (Up1 and Up2) and two sites downstream (Dw1 and Dw2) from the mine. Metals bioaccumulation was determined in gills, mantle, digestive gland, muscle and hemolymph and the following biomarkers were measured in A. trapesialis tissues: total antioxidant capacity against peroxyl radicals, metallothionein content, lipid peroxidation (LPO), proteins carbonylation, glutathione S-transferase activity, superoxide dismutase activity and acetylcholinesterase (AChE) activity. The results showed that Al and Fe bioaccumulation in the gills and hemolymph, Al bioaccumulation in the mantle and muscle, increased LPO in the gills (Dw1 and Dw2) and mantle (Dw1), as well as reduced AChE activity in the muscle (Dw1 and Dw2) should be considered effective biomarkers for monitoring coal mining areas. A. trapesialis proved to be an efficient biological model, considering that biomarkers responses were observed in the clams after only 96h of confinement at Dw sites, accordingly this species could be a good candidate for monitoring Neotropical freshwaters. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Seawater acidification affects the physiological energetics and spawning capacity of the Manila clam Ruditapes philippinarum during gonadal maturation.

    Science.gov (United States)

    Xu, Xian; Yang, Feng; Zhao, Liqiang; Yan, Xiwu

    2016-06-01

    Ocean acidification is predicted to have widespread implications for marine bivalve mollusks. While our understanding of its impact on their physiological and behavioral responses is increasing, little is known about their reproductive responses under future scenarios of anthropogenic climate change. In this study, we examined the physiological energetics of the Manila clam Ruditapes philippinarum exposed to CO 2 -induced seawater acidification during gonadal maturation. Three recirculating systems filled with 600 L of seawater were manipulated to three pH levels (8.0, 7.7, and 7.4) corresponding to control and projected pH levels for 2100 and 2300. In each system, temperature was gradually increased ca. 0.3°C per day from 10 to 20°C for 30days and maintained at 20°C for the following 40days. Irrespective of seawater pH levels, clearance rate (CR), respiration rate (RR), ammonia excretion rate (ER), and scope for growth (SFG) increased after a 30-day stepwise warming protocol. When seawater pH was reduced, CR, ratio of oxygen to nitrogen, and SFG significantly decreased concurrently, whereas ammonia ER increased. RR was virtually unaffected under acidified conditions. Neither temperature nor acidification showed a significant effect on food absorption efficiency. Our findings indicate that energy is allocated away from reproduction under reduced seawater pH, potentially resulting in an impaired or suppressed reproductive function. This interpretation is based on the fact that spawning was induced in only 56% of the clams grown at pH 7.4. Seawater acidification can therefore potentially impair the physiological energetics and spawning capacity of R. philippinarum. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Extreme differences between hemoglobins I and II of the clam Lucina pectinalis in their reactions with nitrite.

    Science.gov (United States)

    Bonaventura, Celia; Henkens, Robert; De Jesus-Bonilla, Walleska; Lopez-Garriga, Juan; Jia, Yiping; Alayash, Abdu I; Siburt, Claire J Parker; Crumbliss, Alvin L

    2010-10-01

    The clam Lucina pectinalis supports its symbiotic bacteria by H₂S transport in the open and accessible heme pocket of Lucina Hb I and by O₂ transport in the narrow and crowded heme pocket of Lucina Hb II. Remarkably, air-equilibrated samples of Lucina Hb I were found to be more rapidly oxidized by nitrite than any previously studied Hb, while those of Lucina Hb II showed an unprecedented resistance to oxidation induced by nitrite. Nitrite-induced oxidation of Lucina Hb II was enabled only when O₂ was removed from its active site. Structural analysis revealed that O₂ "clams up" the active site by hydrogen bond formation to B10Tyr and other distal-side residues. Quaternary effects further restrict nitrite entry into the active site and stabilize the hydrogen-bonding network in oxygenated Lucina Hb II dimers. The dramatic differences in nitrite reactivities of the Lucina Hbs are not related to their O₂ affinities or anaerobic redox potentials, which were found to be similar, but are instead a result of differences in accessibility of nitrite to their active sites; i.e. these differences are due to a kinetic rather than thermodynamic effect. Comparative studies revealed heme accessibility to be a factor in human Hb oxidation by nitrite as well, as evidenced by variations of rates of nitrite-induced oxidation that do not correlate with R and T state differences and inhibition of oxidation rate in the presence of O₂. These results provide a dramatic illustration of how evolution of active sites with varied heme accessibility can moderate the rates of inner-sphere oxidative reactions of Hb and other heme proteins. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. Inactivation of Vibrio cholerae O1 El Tor inoculated into Peruvian ''choro'' mussels (Aulacomya ater) and two species of clams (Argopecten purpuratus and Gari solida) using medium-dose irradiation

    International Nuclear Information System (INIS)

    Torres, Z.; Bernuy, B.; Kahn, G.; Zapata, G.; Vivanco, M.; Guzman, E.; Leon, R.

    2001-01-01

    The radiation decimal reduction dose (D 10 ) for Vibrio cholerae O1 biotype El Tor inoculated through the natural feeding system into three species of bivalve mollusks from the Peruvian Pacific coast: ''choro'' mussels (Aulacome ater), ''abanico'' clams (Argopecten purpuratus), and common clams (Gari solida), was determined in vivo. The D 10 value obtained in vivo was 0.14 kGy in all mollusks tested. Concurrent studies conducted to determine the potential use of irradiation to extend the microbiological shelf-life of the mollusks during post-irradiation storage at 0-1 deg. C indicated that a dose of 1.0 kGy was optimal for choro mussels and abanico clams, whereas 2.0 kGy produced the best results when treating common clams. Shelf-life extension thus achieved was 31 days for choro mussels, 16 days for abanico clams, and 21 days for common clams. Non-irradiated control samples of all mollusks spoiled after 17 days of refrigerated storage. There were no significant (p<.05) adverse effects from the application of the optimal radiation treatments on the sensory characteristics (i.e. appearance, odor, flavor, and texture) of the mollusks. Total volatile basic nitrogen (VBN) and pH values were examined for use as indexes of seafood freshness. (author)

  8. Influence of the toxicity of cryoprotective agents on the involvement of insulin-like growth factor-I receptor in surf clam (Spisula sachalinensis) larvae.

    Science.gov (United States)

    Choi, Youn Hee; Nam, Taek Jeong

    2014-01-01

    The signaling of insulin-like growth factor-I (IGF-I) is involved in the development, growth, reproduction and aging of vertebrates. However, few studies have investigated the involvement of IGF-I during states of extreme shock, such as those induced by potently toxic cryoprotective agents (CPAs) or low temperature conditions, in bivalves. We investigated the toxicity of CPAs and the potential relationship between larval viability and the IGF-I receptor (IGF-IR) after treatment with CPAs or freezing in surf clam (Spisula sachalinensis) larvae. The umbo larvae and different concentrations of CPAs (dimethyl sulfoxide, DMSO; ethylene glycol, EG) were used to investigate the toxicity of CPAs and the vitrification of surf clam larvae. The relationship between larval viability and the IGF-I receptor (IGF-IR) after treatment with CPAs or freezing was investigated using immunoblot analysis. An increase in concentration greater than 4M DMSO was fatal in larvae; however, 5M EG combined with a mixture of CPAs had no harmful effects. Moreover, live larvae immersed in a 5M EG solution remained intact and maintained their normal shape and organs. However, even though the larvae survived the CPA toxicity test, none of the vitrified larvae survived. After immersion into CPAs and vitrification, 97-kDa IGF-IR ß-subunits could be detected in all larvae; but tyrosine phosphorylation of the intracellular β-subunits was detected only in the control and live groups. IGF-IR was activated in the umbo larvae but not in dead surf clam larvae treated with CPA and frozen. Activation of IGF-IR has relevance to the umbo larval stage in live surf clams treated with CPAs.

  9. Effects of environmental and biological conditions on the recruitment and growth of the Manila clam Ruditapes philippinarum on the west coast of Korea

    Science.gov (United States)

    Kim, Sang Lyeol; Kwon, Soon Hyun; Lee, Hyung-Gon; Yu, Ok Hwan

    2017-03-01

    The distribution of the Manila clam Ruditapes philippinarum, which is often dominant in intertidal zones, is influenced by both environmental and biological conditions. However, there have been few comprehensive studies on the interactive effects of these two groups of factors. The present study examined the environmental and biological parameters determining the population dynamics of the clams that is a dominant component of the intertidal communities of Euhangri and Padori on the west coast of Korean peninsula. We collected R. philippinarum and other members of the macrobenthos (> 1 mm long) monthly from 0.25 m2 quadrats deployed in the intertidal zones at Euhangri, Taean, and Padori during the period from August 2013 to January 2015. Physicochemical parameters of the water and sediment were measured at the same time. Water temperature and salinity is high and low in the summer to winter, respectively. While mean grain size of the sediment was higher at Euhangri than at Padori, total mean density of R. philippinarum was higher at Euhangri (325 ind./ 0.25 m2 at Padori vs. 194 ind./0.25 m2 at Euhangri). Settled spat (population increased, the condition index of individual clams decreased, but as the population density of the spat increased the body condition index increased. The chlorophyll a content of the sediments at Padori exceeded that at Euhangri and decreased as the population of R. philippinarum increased. The shapes of R. philippinarum shells at Euhangri were more prolate than those at Padori, and the condition index at Euhangri exceeded that at Padori, indicating better growth conditions at Euhangri. The condition index and density of R. philippinarum were affected by the amount of chlorophyll a in the water column and in the sediment. The recruitment success of spats was negatively influenced by spat density. We suggest that regulation of habitat conditions for R. philippinarum, including the food supply, will optimize production of these commercial

  10. Mating behaviour in laevicaudatan clam shrimp (Crustacea, Branchiopoda and functional morphology of male claspers in a phylogenetic context: a video-based analysis.

    Directory of Open Access Journals (Sweden)

    Zandra M S Sigvardt

    Full Text Available Clam shrimps are freshwater branchiopod crustaceans which often present complicated breeding systems including asexual reproduction (parthenogenesis and mixed mating systems (in androdioecious species both selfing and outcrossing occurs due to the co-presence of hermaphrodites and males. Reproductive patterns of Spinicaudata, which contains most clam shrimp species, have received much attention. Another group of clam shrimps, Laevicaudata, which holds a key position in branchiopod phylogeny, has practically not been studied. As a part of the mating process, males clasp to the carapace margin of the females with a pair (or two pairs of anterior trunk limbs modified as claspers. Previous studies have shown that clasper morphology is important in a phylogenetic context, and that some parts of the claspers in Spinicaudata and Laevicaudata may have undergone a remarkable parallel evolution. Here we have used video microscopy to study aspects of the mating behaviour, egg extrusion, and fertilization in Lynceus brachyurus (Laevicaudata. It is shown that fertilization is likely to be external and that the peculiar tri-lobed lateral lamellae of female's hind body assist in guiding the egg mass to the exopodal egg carriers where they are collected by their distal setation. The functional morphology of the male claspers was studied in detail by close-up video recordings. The movable "finger" of the clasper bends around the female's carapace edge and serves to hold the female during mating. The larger palp grasps around the female carapace margin in a way very similar to the movable "finger", possibly indirectly providing sensory input on the "finger" position. A brief comparative study of the claspers of a spinicaudatan clam shrimp showed both similarities and differences to the laevicaudatan claspers. The presence of two pairs of claspers in Spinicaudata seems to give males a better hold of the female which may play a role during extended mate guarding.

  11. Effects of salinity, temperature and food type on the uptake and elimination rates of cd, cr, and zn in the asiatic clam corbicula fluminea

    Science.gov (United States)

    Lee, Jung-Suk; Lee, Byeong-Gweon

    2005-06-01

    Laboratory radiotracer experiments were conducted to determine assimilation efficiencies (AE) from ingested algal food and oxic sediment particles, uptake rates from the dissolved phase, and the efflux rates of Cd, Cr and Zn in the Asiatic clam Corbicula fluminea. Among three elements, AE from both algal and sediment food was greatest for Cd, followed by Zn and Cr. The AEs of tested elements from algal food (Phaeodactylum tricornutum) were consistently higher than those from sediments at a given salinity and temperature. The influence of salinity (0, 4 and 8 psu) and temperature (5, 13 and 21¼) on the metal AEs was not evident for most tested elements, except Cd AEs from sediment. The rate constant of metal uptake from the dissolved phase ( k u was greatest for Cd, followed by Zn and Cr in freshwater media. However, in saline water, the k u of Zn were greater than those of Cd. The influx rate of all tested metals increased with temperature. The efflux rate constant was greatest for Cr (0.02 d-1), followed by Zn (0.010~0.017 d-1) and Cd (0.006 d-1). The efflux rate constant for Zn in clam tissues depurated in 0 psu (0.017 d-1) was faster than that in 8 psu (0.010 d-1). Overall results showed that the variation of salinity and temperature in estuarine systems can considerably influence the metal bioaccumulation potential in the estuarine clam C. fluminea. The relatively high Cd accumulation capacity of C. fluminea characterized by the high AE, high dissolved influx rate and low efflux rate, suggested that this clam species can be used as an efficient biomonitor for the Cd contamination in freshwater and estuarine environments.

  12. Intra-specific diet shift in manila clams (Ruditapes philippinarum) as revealed by carbon and nitrogen stable isotopes and fatty acid biomarker

    Science.gov (United States)

    Suh, Y.; Shin, K.

    2011-12-01

    Manila clams sampled in Seonjae Island, Korea with shell lengths (SL) below 19.76 mm in average showed a significantly depleted carbon and nitrogen isotope values (Pmetabolism of fatty acids not required by the animals and an accumulation of the essential fatty acids (PUFA). In addition, their higher energy requirement and more active state of development would further diminish lipid reserve of the species.

  13. Comparison of two methods for the detection of hepatitis A virus in clam samples (Tapes spp.) by reverse transcription-nested PCR.

    Science.gov (United States)

    Suñén, Ester; Casas, Nerea; Moreno, Belén; Zigorraga, Carmen

    2004-03-01

    The detection of hepatitis A virus in shellfish by reverse transcription-nested polymerase chain reaction (RT-nested PCR) is hampered mainly by low levels of virus contamination and PCR inhibitors in shellfish. In this study, we focused on getting a rapid and sensitive processing procedure for the detection of HAV by RT-nested PCR in clam samples (Tapes spp.). Two previously developed processing methods for virus concentration in shellfish have been improved upon and compared. The first method involves acid adsorption, elution, polyethylene glycol (PEG) precipitation, chloroform extraction and PEG precipitation. The second method is based on elution with a glycine buffer at pH 10, chloroform extraction and concentration by ultracentrifugation. Final clam concentrates were processed by RNA extraction or immunomagnetic capture of viruses (IMC) before the RT-nested PCR reaction. Both methods of sample processing combined with the RNA extraction from the concentrates were very efficient when they were assayed in seeded and naturally contaminated samples. The results show that the first method was more effective in removal inhibitors and the second was simpler and faster. The IMC of HAV from clam concentrates processed by method 1 was revealed to be a very effective method of simultaneously removing residual PCR inhibitors and of concentrating the virus.

  14. Fracture toughness and fracture behavior of CLAM steel in the temperature range of 450 °C-550 °C

    Science.gov (United States)

    Zhao, Yanyun; Liang, Mengtian; Zhang, Zhenyu; Jiang, Man; Liu, Shaojun

    2018-04-01

    In order to analyze the fracture toughness and fracture behavior (J-R curves) of China Low Activation Martensitic (CLAM) steel under the design service temperature of Test Blanket Module of the International Thermonuclear Experimental Reactor, the quasi-static fracture experiment of CLAM steel was carried out under the temperature range of 450 °C-550 °C. The results indicated that the fracture behavior of CLAM steel was greatly influenced by test temperature. The fracture toughness increased slightly as the temperature increased from 450 °C to 500 °C. In the meanwhile, the fracture toughness at 550 °C could not be obtained due to the plastic deformation near the crack tip zone. The microstructure analysis based on the fracture topography and the interaction between dislocations and lath boundaries showed two different sub-crack propagation modes: growth along 45° of the main crack direction at 450 °C and growth perpendicular to the main crack at 500 °C.

  15. Laboratory simulation reveals significant impacts of ocean acidification on microbial community composition and host-pathogen interactions between the blood clam and Vibrio harveyi.

    Science.gov (United States)

    Zha, Shanjie; Liu, Saixi; Su, Wenhao; Shi, Wei; Xiao, Guoqiang; Yan, Maocang; Liu, Guangxu

    2017-12-01

    It has been suggested that climate change may promote the outbreaks of diseases in the sea through altering the host susceptibility, the pathogen virulence, and the host-pathogen interaction. However, the impacts of ocean acidification (OA) on the pathogen components of bacterial community and the host-pathogen interaction of marine bivalves are still poorly understood. Therefore, 16S rRNA high-throughput sequencing and host-pathogen interaction analysis between blood clam (Tegillarca granosa) and Vibrio harveyi were conducted in the present study to gain a better understanding of the ecological impacts of ocean acidification. The results obtained revealed a significant impact of ocean acidification on the composition of microbial community at laboratory scale. Notably, the abundance of Vibrio, a major group of pathogens to many marine organisms, was significantly increased under ocean acidification condition. In addition, the survival rate and haemolytic activity of V. harveyi were significantly higher in the presence of haemolymph of OA treated T. granosa, indicating a compromised immunity of the clam and enhanced virulence of V. harveyi under future ocean acidification scenarios. Conclusively, the results obtained in this study suggest that future ocean acidification may increase the risk of Vibrio pathogen infection for marine bivalve species, such as blood clams. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. The Whitish Inner Mantle of the Giant Clam, Tridacna squamosa, Expresses an Apical Plasma Membrane Ca2+-ATPase (PMCA Which Displays Light-Dependent Gene and Protein Expressions

    Directory of Open Access Journals (Sweden)

    Yuen K. Ip

    2017-10-01

    Full Text Available Giant clams live in symbiosis with extracellular zooxanthellae and display high rates of growth and shell formation (calcification in light. Light-enhanced calcification requires an increase in the supply of Ca2+ to, and simultaneously an augmented removal of H+ from, the extrapallial fluid where shell formation occurs. We have obtained the complete coding cDNA sequence of Plasma Membrane Ca2+-ATPase (PMCA from the thin and whitish inner mantle, which is in touch with the extrapallial fluid, of the giant clam Tridacna squamosa. The deduced PMCA sequence consisted of an apical targeting element. Immunofluorescence microscopy confirmed that PMCA had an apical localization in the shell-facing epithelium of the inner mantle, whereby it can actively secrete Ca2+ in exchange for H+. More importantly, the apical PMCA-immunofluorescence of the shell-facing epithelium of the inner mantle increased significantly after 12 h of exposure to light. The transcript and protein levels of PMCA/PMCA also increased significantly in the inner mantle after 6 or 12 h of light exposure. These results offer insights into a light-dependable mechanism of shell formation in T. squamosa and a novel explanation of light-enhanced calcification in general. As the inner mantle normally lacks light sensitive pigments, our results support a previous proposition that symbiotic zooxanthellae, particularly those in the colorful and extensible outer mantle, may act as light-sensing elements for the host clam.

  17. Large-scale mitochondrial COI gene sequence variability reflects the complex colonization history of the invasive soft-shell clam, Mya arenaria (L.) (Bivalvia)

    Science.gov (United States)

    Lasota, Rafal; Pierscieniak, Karolina; Garcia, Pascale; Simon-Bouhet, Benoit; Wolowicz, Maciej

    2016-11-01

    The aim of the study was to determine genetic diversity in the soft-shell clam Mya arenaria on a wide geographical scale using mtDNA COI gene sequences. Low levels of genetic diversity was found, which can most likely be explained by a bottleneck effect during Pleistocene glaciations and/or selection. The geographical genetic structuring of the studied populations was also very low. The star-like phylogeny of the haplotypes indicates a relatively recent, rapid population expansion following the glaciation period and repeated expansion following the founder effect(s) after the initial introduction of the soft-shell clam to Europe. North American populations are characterized by the largest number of haplotypes, including rare ones, as expected for native populations. Because of the founder effect connected with initial and repeated expansion events, European populations have significantly lower numbers of haplotypes in comparison with those of North America. We also observed subtle differentiations among populations from the North and Baltic seas. The recently founded soft-shell clam population in the Black Sea exhibited the highest genetic similarity to Baltic populations, which confirmed the hypothesis that M. arenaria was introduced to the Gulf of Odessa from the Baltic Sea. The most enigmatic results were obtained for populations from the White Sea, which were characterized by high genetic affinity with American populations.

  18. Phytoplankton growth balanced by clam and zooplankton grazing and net transport into the low-salinity zone of the San Francisco Estuary

    Science.gov (United States)

    Kimmerer, Wim J.; Thompson, Janet K.

    2014-01-01

    We estimated the influence of planktonic and benthic grazing on phytoplankton in the strongly tidal, river-dominated northern San Francisco Estuary using data from an intensive study of the low salinity foodweb in 2006–2008 supplemented with long-term monitoring data. A drop in chlorophyll concentration in 1987 had previously been linked to grazing by the introduced clam Potamocorbula amurensis, but numerous changes in the estuary may be linked to the continued low chlorophyll. We asked whether phytoplankton continued to be suppressed by grazing and what proportion of the grazing was by benthic bivalves. A mass balance of phytoplankton biomass included estimates of primary production and grazing by microzooplankton, mesozooplankton, and clams. Grazing persistently exceeded net phytoplankton growth especially for larger cells, and grazing by microzooplankton often exceeded that by clams. A subsidy of phytoplankton from other regions roughly balanced the excess of grazing over growth. Thus, the influence of bivalve grazing on phytoplankton biomass can be understood only in the context of limits on phytoplankton growth, total grazing, and transport.

  19. Impact of hypoxia on hemolymph contamination by uranium in an aquatic animal, the freshwater clam Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Damien [Universite Bordeaux 1, CNRS, UMR 5805 EPOC, Place du Dr Peyneau, 33120 Arcachon (France)], E-mail: d.tran@epoc.u-bordeaux1.fr; Massabuau, Jean-Charles [Universite Bordeaux 1, CNRS, UMR 5805 EPOC, Place du Dr Peyneau, 33120 Arcachon (France)], E-mail: jc.massabuau@epoc.u-bordeaux1.fr; Garnier-Laplace, Jacqueline [Laboratoire de Radioecologie et Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat. 186, BP3, 13115 Saint Paul-Lez-Durance, Cedex (France)], E-mail: Jacqueline.Garnier-Laplace@irsn.fr

    2008-12-15

    Multi-stress situations are a major question and low-oxygenated waters (hypoxia) are a growing problem. Importantly, hypoxia stimulates the ventilatory flow rate in aquatic animals and this increases gill exposure to contaminants. Surprisingly, in the freshwater clam Corbicula fluminea, this is associated with increased bioaccumulation of uranium in gills but not in deep tissues. We searched for an explanation by analyzing hemolymph U-transport in Corbicula exposed to 0.36 {mu}M dissolved uranium at various O{sub 2}-levels for 10 days. In hypoxia, one observed an increased U concentration in the arterial hemolymph flowing from gills to tissues but this was not associated with an increased U concentration in the venous hemolymph nor in the other tissues. We conclude that the cardiac flow rate must have decreased to explain this absence of over-accumulation. In addition to its already known deleterious effects, uranium can thus deeply impair cardiac flow rate in exposed aquatic animals during multi-stress exposures. - Uranium contamination enhanced by hypoxia can deeply impair circulatory hemolymph flow in aquatic animals.

  20. Effects of Calcination on the Crystallography and Nonbiogenic Aragonite Formation of Ark Clam Shell under Ambient Condition

    Directory of Open Access Journals (Sweden)

    Chee Wah Loy

    2016-01-01

    Full Text Available This paper presents a study of crystallographic evolution of disposed ark clam shell (ACS after calcination at 400–1400°C which was kept at room temperature under ambient condition in Malaysia during nine months. A better understanding of hydration and recarbonation of ACS powder (≤63 μm after calcination was discovered by PXRD and FTIR. The research focuses on the crystallographic transformation, biogenic calcite decomposition, and unusual atmospheric aragonite formation in ACS after calcination and atmospheric air exposure. Ex situ PXRD showed calcite present in ACS at ≤900°C. ACS transformed to pyrogenic fcc CaO at ≥800°C after three months. Long term atmospheric air exposure of decarbonized ACS caused nucleation of nonbiogenic aragonite, vaterite, calcite, and portlandite. However, in situ PXRD analysis of ACS at instantaneous temperature without cooling process does not indicate the presence of aragonite, vaterite, and portlandite crystals. FTIR spectra revealed CaO–CO2 bond in ACS dissociated with temperature (600–900°C to form CaO and CO2. Ca–OH bond was also traced in FTIR spectra of ≥700°C. It resulted by hydroadsorption of CaO with H2O in atmospheric air.

  1. Identification of functional genes involved in Cd(2+) response of Chinese surf clam (Mactra chinensis) through transcriptome sequencing.

    Science.gov (United States)

    Zhang, Jingjing; Li, Hongjun; Qin, Yanjie; Ye, Sheng; Liu, Min

    2016-01-01

    The Chinese surf clam Mactra chinensis is an economically important bivalve species in the coastal waters of Liaoning and Shandong Province, China. In this study, we carried out transcriptome sequencing to develop molecular resources for M. chinensis and conducted an acute test of Cd(2+) stimulation through quantitative real-time PCR (qRT-PCR) to analyze the relative expression of six functional genes. A total of 100,839 transcripts and 56,712 unigenes were obtained from 39.9 million filtered reads and 21,305 unigenes were annotated by hitting against NCBI database. According to the results of qRT-PCR, heat shock protein 22 (Hsp22) and cytochrome P450 (CYP450(2C31)) were inhibited in the low concentration, and induced in the high concentration of Cd(2+); thioredoxin peroxidase (TPx-A) was at normal level in low concentration, but induced in high concentration of Cd(2+); glutathione peroxidase A (GPA), glutathione peroxidase 1 (GPA1) and Mn superoxide dismutase gene (MnSOD) were down-regulated when exposed to any treatment groups. Expression levels of the six functional genes following Cd(2+) exposure indicated that these genes were linked to environmental stress. Moreover, the present work enriched the molecule genetic data of M. chinensis. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Identification and expression of antioxidant and immune defense genes in the surf clam Mesodesma donacium challenged with Vibrio anguillarum.

    Science.gov (United States)

    Maldonado-Aguayo, W; Lafarga-De la Cruz, F; Gallardo-Escárate, C

    2015-02-01

    The immune system in marine invertebrates is mediated through cellular and humoral components, which act together to address the action of potential pathogenic microorganisms. In bivalve mollusks biomolecules implicated in oxidative stress and recognition of pathogens have been involved in the innate immune response. To better understand the molecular basis of the immune response of surf clam Mesodesma donacium, qPCR approaches were used to identify genes related to its immune response against Vibrio anguillarum infection. Genes related to oxidative stress response and recognition of pathogens like superoxide dismutase (MdSOD), catalase (MdCAT), ferritin (MdFER) and filamin (MdFLMN) were identified from 454-pyrosequencing cDNA library of M. donacium and were evaluated in mantle, adductor muscle and gills. The results for transcripts expression indicated that MdSOD, MdFLMN and MdFER were primarily expressed in the muscle, while MdCAT was more expressed in gills. Challenge experiments with the pathogen V. anguillarum had showed that levels of transcript expression for MdSOD, MdCAT, MdFER, and MdFLMN were positively regulated by pathogen, following a time-dependent expression pattern with significant statistical differences between control and challenge group responses (p<0.05). These results suggest that superoxide dismutase, catalase, ferritin and filamin, could be contributing to the innate immune response of M. donacium against the pathogen V. anguillarum. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Purification, molecular cloning, and application of a novel sphingomyelin-binding protein (clamlysin) from the brackishwater clam, Corbicula japonica.

    Science.gov (United States)

    Takara, Taketoshi; Nakagawa, Tetsuto; Isobe, Masami; Okino, Nozomu; Ichinose, Sachiyo; Omori, Akira; Ito, Makoto

    2011-05-01

    A novel sphingomyelin-binding protein (clamlysin) was purified from the foot muscle of a brackishwater clam, Corbicula japonica. The purified 24.8-kDa protein lysed sheep, horse and rabbit erythrocytes and the hemolytic activity was inhibited by sphingomyelin, but not other phospholipids or glycosphingolipids. The open reading frame of the clamlysin gene encoded a putative 26.9-kDa protein (clamlysin B) which showed high sequence similarity with the actinoporin family. A surface plasmon resonance assay confirmed that clamlysin B specifically bound to sphingomyelin. Furthermore, two cDNA variants of clamlysin, encoding putative 31.4 kDa (clamlysin A) and 11 kDa (clamlysin C) proteins, were isolated. Only the 31.4-kDa variant was found to exhibit sphingomyelin-binding activity. Clamlysin A and B, but not C, shared a sequence (domain II) conserved in all known sphingomyelin-binding proteins. Domain II fused with a glutathione S-transferase bound to sphingomyelin. Horse erythrocytes, mouse melanoma B16 and GM95 cells, and Chinese hamster ovary CHO-K1 cells, but not the same cells treated with bacterial sphingomyelinase, were immunostained with clamlysin B. These results indicate that clamlysin B binds to the sphingomyelin of living cells and thus would be useful as a molecular probe to detect sphingomyelin. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Effect of post-weld heat treatment on the mechanical properties of electron beam welded joints for CLAM steel

    Science.gov (United States)

    Wu, Qingsheng; Zheng, Shuhui; Liu, Shaojun; Li, Chunjing; Huang, Qunying

    2013-11-01

    In this paper the microstructure and mechanical properties of electron beam weld (EBW) joints for China low activation martensitic (CLAM) steel, which underwent a series of different post weld heat treatments (PWHTs) were studied. The aim of the study was to identify suitable PWHTs that give a good balance between strength and toughness of the EBW joints. The microstructural analyses were performed by means of optical microscope (OM) and scanning electron microscope (SEM). The mechanical properties were determined via tensile tests and Charpy impact tests. The results showed that the tensile strength of the as-weld joint (i.e. without any PWHT) were close to that of the base metal, but the impact toughness was only 13% of that of the base metal due to the existence of a delta-ferrite microstructure. To achieve a significant improvement in toughness a PWHT needs to be performed. If a one-step PWHT is applied tempering at 760 °C for 2 h gives EBW joints with high strength at a still acceptable toughness level. If a two-step PWHT is applied, a process involving quenching at 980 °C for 0.5 h followed by tempering at 740 °C or 760 °C for 2 h gives EBW joints with high strength and toughness properties. Whenever possible a two-step PWHT should be applied in favor of a one-step process, because of higher resulting strength and toughness properties.

  5. Protective effects of water extract of clam on normal and CCl₄-induced damage in primary cultured rat hepatocytes.

    Science.gov (United States)

    Chi, H M; Chou, S T; Lin, S C; Su, Z Y; Sheen, Lee-Yan

    2010-01-01

    The objective of this study was to investigate the effects of various concentrations and incubation times of water extract of clam (WEC) on glutathione, its antioxidant and the detoxification defense systems in normal and CCl₄-induced oxidative damaged primary rat hepatocytes. This study showed that when the hepatocytes were treated with WEC (0.14 ~ 1.68 mg/ml), the intracellular glutathione (GSH) levels, GSH/GSSG ratio, and the activities of GSH-related enzymes (GPx, GRd, and GST) were higher than those in the control at 24 or 48 hour treatments. However, the lactate dehydrogenase (LDH) leakage and microscopic observations did not differ from those of the control. Yet, when the hepatocytes were pretreated with various concentrations of WEC for 24 hours and then exposed to 5 mM carbon tetrachloride (CCl₄) for 1 hour, at concentrations of WEC between 0.42 ~ 1.68 mg/ml, the viabilities, intracellular GSH level, and activities of GST and GPx were significantly increased compared to those of the CCl₄-treated control group (p WEC could improve the viability and the capabilities of detoxification and antioxidation in hepatocytes by increasing the GSH level and the activities of GSH-related enzymes.

  6. A freshwater clam (Corbicula fluminea) extract improves cholesterol metabolism in rats fed on a high-cholesterol diet.

    Science.gov (United States)

    Chijimatsu, Takeshi; Tatsuguchi, Iwao; Abe, Kazuaki; Oda, Hiroaki; Mochizuki, Satoshi

    2008-10-01

    The effect of a freshwater clam (Corbicula fluminea) extract (FCE) on cholesterol metabolism in rats fed on a high-cholesterol diet was investigated. When rats were fed various amounts of FCE in addition to the high-cholesterol diet for 2 wk, the serum and hepatic cholesterol levels were gradually reduced in a dose-dependent manner, as compared with the control group. The excretion of neutral sterols and bile acids into the feces was increased by feeding FCE. Several phytosterols were detected in the feces of rats fed on the FCE-containing diet. In addition, substantial amounts of phytosterols were found in FCE. Cholesterol 7alpha-hydroxylase (CYP7A1) mRNA in the liver of the rats fed on the FCE-containing diets was higher than that of rats fed on the high-cholesterol diets without FCE. These results may suggest that enhanced cholesterol degradation and the excretion of neutral sterols and bile acids contributed to the hypocholesterolemic effect of FCE observed in the hypercholesterolemic rats fed on the high-cholesterol diet.

  7. Genetic diversity analysis of Asian clam Corbicula fluminea in the Hongze Lake based on mitochondrial cytochrome b gene.

    Science.gov (United States)

    Zhu, Chuankun; Li, Jin; Xie, Songguang; Ding, Huaiyu; Pan, Zhengjun; Wang, Hui; Chang, Guoliang

    2017-03-24

    The Asian clam Corbicula fluminea is a small bivalve with high nutritional and medical values. However, natural resources of C. fluminea have declined in many areas of China including the Hongze Lake. In this study, 119 individuals from 10 sites of this lake and 2 outgroups were analyzed using a 456 bp mitochondrial cytochrome b (cytb) gene segment. Totally, 19 polymorphic sites were detected, which defined 16 haplotypes. Polymorphism varied among the 10 populations with those at the water inlet being more polymorphic. Most F ST values among these populations were below 0.15 with the overall value of 0.060 (p < .05), meanwhile, the overall gene flow was 7.67, both of which indicated the low level of population differentiation in this lake. Neutrality test and mismatch analyses indicated that population explosion may have occurred in this lake. The results obtained in this study will provide useful information for artificial breeding and resource protection of this species in the Hongze Lake.

  8. Linking valve closure behavior and sodium transport mechanism in freshwater clam Corbicula fluminea in response to copper.

    Science.gov (United States)

    Liao, Chung-Min; Lin, Chieh-Ming; Jou, Li-John; Chiang, Kuo-Chin

    2007-06-01

    The purpose of this study is to develop a mechanistic model to describe a conceptually new "flux-biological response" approach based on biotic ligand model (BLM) and Michaelis-Menten (M-M) kinetics to allow the linkage between valve closure behavior and sodium (Na) transport mechanism in freshwater clam Corbicula fluminea in response to waterborne copper (Cu). We test the proposed model against published data regarding Na uptake kinetics in rainbow trout and Na uptake profile in C. fluminea, confirming that the predictive model is robust. Here, we show that the predicted M-M maximum Cu internalization flux in C. fluminea is 0.369 micromolg(-1)h(-1) with a half-saturation affinity constant of 7.87x10(-3) microM. Dynamics of Na uptake and valve closure daily rhythm driven by external Cu can also be predicted simultaneously. We suggest that this "Na transport-valve closure behavior" approach might provide the basis of a future design of biomonitoring tool.

  9. Impact of hypoxia on hemolymph contamination by uranium in an aquatic animal, the freshwater clam Corbicula fluminea.

    Science.gov (United States)

    Tran, Damien; Massabuau, Jean-Charles; Garnier-Laplace, Jacqueline

    2008-12-01

    Multi-stress situations are a major question and low-oxygenated waters (hypoxia) are a growing problem. Importantly, hypoxia stimulates the ventilatory flow rate in aquatic animals and this increases gill exposure to contaminants. Surprisingly, in the freshwater clam Corbicula fluminea, this is associated with increased bioaccumulation of uranium in gills but not in deep tissues. We searched for an explanation by analyzing hemolymph U-transport in Corbicula exposed to 0.36 microM dissolved uranium at various O2-levels for 10 days. In hypoxia, one observed an increased U concentration in the arterial hemolymph flowing from gills to tissues but this was not associated with an increased U concentration in the venous hemolymph nor in the other tissues. We conclude that the cardiac flow rate must have decreased to explain this absence of over-accumulation. In addition to its already known deleterious effects, uranium can thus deeply impair cardiac flow rate in exposed aquatic animals during multi-stress exposures.

  10. Effects of environmental factors on growth, survival, and metamorphosis of geoduck clam (Panopea japonica A. Adams, 1850 larvae

    Directory of Open Access Journals (Sweden)

    Zhongming Huo

    2017-11-01

    Full Text Available A series of experiments were conducted to evaluate the effects of temperature, salinity, diet, and stocking density on the growth, survival, and metamorphosis of geoduck clam Panopea japonica larvae. The larvae all died at a temperature of 22 °C after day 12, suggesting that the larvae of P. japonica could not survive when the temperature was higher than 22 °C. P. japonica could be incubated at 19 °C for the fast growth, high survival and metamorphosis of larvae. The embryos all died when the salinity was below 25 ppt. The larvae showed poor survival when the salinity was below 25 ppt, with all larvae dying before day 12, suggesting that larvae are sensitive to low salinity. The optimum salinity for the growth, survival and metamorphosis of larvae was 32 ppt. The use of a mixture of Isochrysis galbana and Nitzschia closterium (1:1 as a food source for the P. japonica larvae improved their growth, survival, and metamorphosis. A density of 20 individuals/ml appeared to be optimal for normal D-larvae of Panopea japonica, and 3–9 larvae/ml was optimal for the growth and survival of the P. japonica larvae raised in the hatchery.

  11. Histological survey of symbionts and other conditions of pod razor clam Ensis siliqua (Linnaeus, 1758) in Galicia (NW Spain).

    Science.gov (United States)

    Ruiz, Maite; Darriba, Susana; Rodríguez, Rosana; López, Carmen

    2013-01-01

    The aim of the present study was to carry out a survey of parasites and other conditions affecting pod razor clam populations, Ensis siliqua, in two beds from Galicia (NW Spain). In Galicia, the production of E. siliqua has increased in recent years due to the development of specific plans for its exploitation, however few and quite recent pathological studies have been carried out in this species. The results of this study showed the presence of different protozoa as the more prevalent group, especially Nematopsis sp. gregarines, unidentified branchial protozoa, renal coccidia and Trichodina sp. ciliates. Larval stages of trematodes and neoplastic disorders were also observed with lower prevalences. Furthermore, an ultrastructural analysis of two types of unidentified basophilic inclusions, both found in the digestive gland, revealed the presence of icosahedral viral particles and prokaryotic organisms, respectively. None of the parasites detected in E. siliqua from this study was notifiable to the World Organisation for Animal Health (OIE) and the majority of the symbionts and conditions observed in their tissues did not cause host damage. Nevertheless, parasites like bucephalid digenean sporocysts, viral inclusions, prokaryotic infections, disseminated neoplasm or germinoma detected in some samples could cause moderate or severe damage to the host depending on the intensity of infection. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Choking Prevention

    Science.gov (United States)

    ... Healthy Living Healthy Living Healthy Living Nutrition Fitness Sports Oral Health Emotional Wellness Growing Healthy Sleep Safety & Prevention Safety & Prevention Safety and Prevention Immunizations At Home ...

  13. Acute toxicity, toxicokinetics, and tissue target of lead and uranium in the clam Corbicula fluminea and the worm Eisenia fetida: comparison with the fish Brachydanio rerio.

    Science.gov (United States)

    Labrot, F; Narbonne, J F; Ville, P; Saint Denis, M; Ribera, D

    1999-02-01

    The general objective of our work was to propose new reference material for chemical toxicity testing and new sentinel organisms for environmental quality survey programs (freshwater or soils). We also wanted to provide basic toxicological data on the environmental effects of uranium. Thus, we conducted a comparative study to establish the acute toxicity and toxicokinetics of lead (Pb) and uranium (U) to the bivalve mollusc Corbicula fluminea and the terrestrial annelid Eisenia fetida andrei and to compare these findings with those of the well-known teleost fish Brachydanio rerio. We then measured the concentration of these metals in various tissues of the clam and the worm after two periods of exposure (4 and 11 days) to identify the affinities of these tissues for Pb and U. Our results have shown that Pb and U are very toxic to Eisenia and relatively nontoxic to Corbicula. By comparison, Pb was relatively nontoxic and U appeared to be very toxic to the fish. The toxicokinetic studies indicated that the three species are able to accumulate Pb and U, the rate and level of accumulation depending both on the species and the metal. We also found that fish and clams depurate the two metals. Data collected for the worm were conflicting: Pb was not depurated whereas tissue concentrations of U declined after the eighth day of exposure. Our study has also shown that the tissue distribution of Pb in the mollusc and in the earthworm differs significantly from that of U, both after 4 and 11 days exposure. In conclusion, these three species showed potential as bioindicators of environmental contamination by metals. Indeed, they could be used in conjunction to test different compartments of an ecosystem: worms for soils, fish for the water column, and clams for the water/sediment interface.

  14. Effects of ocean acidification driven by elevated CO2 on larval shell growth and abnormal rates of the venerid clam, Mactra veneriformis

    Science.gov (United States)

    Kim, Jee-Hoon; Yu, Ok Hwan; Yang, Eun Jin; Kang, Sung-Ho; Kim, Won; Choy, Eun Jung

    2016-11-01

    The venerid clam ( Mactra veneriformis Reeve 1854) is one of the main cultured bivalve species in intertidal and shallow subtidal ecosystems along the west coast of Korea. To understand the effects of ocean acidification on the early life stages of Korean clams, we investigated shell growth and abnormality rates and types in the D-shaped, umbonate veliger, and pediveliger stages of the venerid clam M. veneriformis during exposure to elevated seawater pCO2. In particular, we examined abnormal types of larval shell morphology categorized as shell deformations, shell distortions, and shell fissures. Specimens were incubated in seawater equilibrated with bubbled CO2-enriched air at (400±25)×10-6 (ambient control), (800±25)×10-6 (high pCO2), or (1 200±28)×10-6 (extremely high pCO2), the atmospheric CO2 concentrations predicted for the years 2014, 2084, and 2154 (70-year intervals; two human generations), respectively, in the Representative Concentration Pathway (RCP) 8.5 scenario. The mean shell lengths of larvae were significantly decreased in the high and extremely high pCO2 groups compared with the ambient control groups. Furthermore, under high and extremely high pCO2 conditions, the cultures exhibited significantly increased abundances of abnormal larvae and increased severity of abnormalities compared with the ambient control. In the umbonate veliger stage of the experimental larvae, the most common abnormalities were shell deformations, distortions, and fissures; on the other hand, convex hinges and mantle protuberances were absent. These results suggest that elevated CO2 exerts an additional burden on the health of M. veneriformis larvae by impairing early development.

  15. Diurnal Fluctuations in Acidification and Hypoxia Reduce Growth and Survival of Larval and Juvenile Bay Scallops (Argopecten irradians) and Hard Clams (Mercenaria mercenaria)

    OpenAIRE

    Gobler, Christopher J.; Clark, Hannah R.; Griffith, Andrew W.; Lusty, Mark W.

    2017-01-01

    Diurnal variations in pH and dissolved oxygen (DO) concentrations are common seasonal phenomena in many eutrophic estuaries, yet few studies have investigated the concurrent effects of low pH and low DO on marine organisms inhabiting these coastal systems. Here, we assess the effects of diurnal variations in pH and DO on the early-life history of two bivalve species native to Northeast US estuaries, the bay scallop (Argopecten irradians) and hard clam (Mercenaria mercenaria). In one set of ex...

  16. Assessing the Effects of Amoxicillin on Antioxidant Enzyme Activities, Lipid Peroxidation and Protein Carbonyl Content in the Clam Ruditapes philippinarum and the Mussel Mytilus galloprovincialis.

    Science.gov (United States)

    Matozzo, Valerio; Battistara, Margherita; Marisa, Ilaria; Bertin, Valeria; Orsetti, Alessandro

    2016-10-01

    In this study, we evaluated the capability of amoxicillin (AMX)-one of the most widely used antibiotics worldwide-to induce oxidative stress in both gills and digestive gland from two bivalve species, the clam Ruditapes philippinarum and the mussel Mytilus galloprovincialis. Superoxide dismutase (SOD) and catalase (CAT) activities, as well as the lipid peroxidation levels (LPO) and protein carbonyl content (PCC), were measured in bivalves exposed to 100, 200 and 400 µg AMX/L for 1, 3 and 7 days. The results obtained demonstrated that AMX affected slightly biomarker responses of molluscs.

  17. Veligers of the invasive Asian clam Corbicula fluminea in the Columbia River Basin: Broadscale distribution, abundance, and ecological associations

    Science.gov (United States)

    Hassett, Whitney; Bollens, Stephen M.; Counihan, Timothy D.; Rollwagen-Bollens, Gretchen; Zimmerman, Julie; Emerson, Joshua E.

    2017-01-01

    The invasive Asian clam Corbicula fluminea was introduced to North America in the 1930s and now inhabits most regions of the conterminous United States; however, the distribution and ecology of C. fluminea in the Columbia River Basin is poorly understood. During 2013 and 2014, 5 Columbia-Snake River reservoirs were sampled monthly from May through September, along with 23 additional lakes and reservoirs sampled once each summer. Associations among C. fluminea veligers, other components of the plankton, and environmental variables were analyzed using non-metric multidimensional scaling and canonical correspondence analysis. Corbicula fluminea veligers were found in high abundances in all mainstem Columbia-Snake River reservoirs, with an annual mean abundance of 71.2 individuals per cubic meter (inds./m3). Only 3 of 23 lakes and (non-mainstem) reservoirs contained C. fluminea, with abundances considerably lower (maximum = 21.2 inds./m3) than in the mainstem reservoirs. A diatom-dominated community preceded the spawning of C. fluminea in early summer at all sites. Corbicula fluminea veligers characterized the plankton community in late summer and were associated with cyanobacteria and high water temperatures. A third community, characterized by cyanobacteria, was apparent in non-mainstem sites in July and August. Our analyses describe the relationship of C. fluminea to the plankton community and environment, which contributes to our understanding of the possible effects of C. fluminea infestations and which waterbodies in the Columbia River Basin are at risk for infestation. Understanding the effects and environmental determinants of invasive mollusks will be increasingly important in the future with the possible arrival of zebra (Dreissena polymorpha) or quagga (D. bugensis) mussels to the region.

  18. A microarray-based analysis of gametogenesis in two Portuguese populations of the European clam Ruditapes decussatus.

    Directory of Open Access Journals (Sweden)

    Joana Teixeira de Sousa

    Full Text Available The European clam, Ruditapes decussatus is a species with a high commercial importance in Portugal and other Southern European countries. Its production is almost exclusively based on natural recruitment, which is subject to high annual fluctuations. Increased knowledge of the natural reproductive cycle of R. decussatus and its molecular mechanisms would be particularly important in providing new highly valuable genomic information for better understanding the regulation of reproduction in this economically important aquaculture species. In this study, the transcriptomic bases of R. decussatus reproduction have been analysed using a custom oligonucleotide microarray representing 51,678 assembled contigs. Microarray analyses were performed in four gonadal maturation stages from two different Portuguese wild populations, characterized by different responses to spawning induction when used as progenitors in hatchery. A comparison between the two populations elucidated a specific pathway involved in the recognition signals and binding between the oocyte and components of the sperm plasma membrane. We suggest that this pathway can explain part of the differences in terms of spawning induction success between the two populations. In addition, sexes and reproductive stages were compared and a correlation between mRNA levels and gonadal area was investigated. The lists of differentially expressed genes revealed that sex explains most of the variance in gonadal gene expression. Additionally, genes like Foxl2, vitellogenin, condensing 2, mitotic apparatus protein p62, Cep57, sperm associated antigens 6, 16 and 17, motile sperm domain containing protein 2, sperm surface protein Sp17, sperm flagellar proteins 1 and 2 and dpy-30, were identified as being correlated with the gonad area and therefore supposedly with the number and/or the size of the gametes produced.

  19. From water to land: How an invasive clam may function as a resource pulse to terrestrial invertebrates.

    Science.gov (United States)

    Novais, Adriana; Souza, Allan T; Ilarri, Martina; Pascoal, Cláudia; Sousa, Ronaldo

    2015-12-15

    Resource pulses are episodes of low frequency, large magnitude and short duration that result in increased resource availability in space and time, with consequences for food web dynamics. Studies assessing the importance of resource pulses by invasive alien species in the interface between terrestrial and aquatic ecosystems are rare, especially those in the direction from water to land. This study assessed the importance of massive die-offs of the Asian clam Corbicula fluminea (Müller, 1774) as a resource pulse to the terrestrial invertebrate community after an extreme climatic event using a manipulative experiment. We used 5 levels of C. fluminea density (0, 100, 500, 1000 and 2000ind·m(-2)), with terrestrial invertebrates being censused 7, 30 and 90days after C. fluminea addition. We also assessed the possible effect of plots position, where plots that delimited the experiment were assigned as edge plots and the remaining as core plots. Clear differences were detected in abundance, biomass, richness and diversity of terrestrial invertebrates depending on the C. fluminea density, time and position. Interestingly, the highest abundance of adult Diptera was observed 7days after C. fluminea addition, whereas that of the other terrestrial invertebrates was on day 30, both with C. fluminea densities higher than 500ind·m(-2) located on the edge of the experimental design. This study highlights the importance of major resource pulses after massive die-offs of invasive bivalves, contributing with remarkable amounts of carrion for adjacent terrestrial systems. Part of this carrion can be consumed directly by a great number of invertebrate species while the remainder can enter the detrital food web. Given the high density and biomass attained by several invasive bivalves worldwide and the predicted increase in the number, intensity and magnitude of extreme climatic events, the ecological importance of this phenomenon should be further investigated. Copyright © 2015

  20. Preparation of fingernails for trace element analysis.

    Science.gov (United States)

    Bank, H L; Robson, J; Bigelow, J B; Morrison, J; Spell, L H; Kantor, R

    1981-10-26

    There are substantial differences in the reported elemental composition of human nails. Most investigators have used extensive washing procedures to minimize environmental contamination, however, such washing poses the risk of extraction of elements bound to the nail matrix. To determine if a portion of this variability could be accounted for by the "washing solutions" used by different investigators, nails were washed in nine solvents previously used for cleaning nails and their residual elemental composition measured by atomic absorption spectroscopy or energy dispersion analysis. In general, treatment with organic solvents resulted in less elemental loss than did treatment with aqueous detergents, while aqueous acids caused the greatest loss. Organic solvents more readily extracted iron and magnesium than calcium, copper and zinc. Virtually all of the magnesium was extracted by distilled water or aqueous detergents.

  1. Fingernails as biological indices of metal exposure

    Indian Academy of Sciences (India)

    Unknown

    metal levels (Cd, Pb, Cr, Mn, Fe, Ni, Cu and Zn) in dif- ferent age groups of subjects with varying personal habits and prone to the hazards of trace metals in their occupa- tional environment. For this study, we have used finger- nails as biopsy material. Male subjects of matching ages in different groups were taken as controls ...

  2. Fingernails as biological indices of metal exposure

    Indian Academy of Sciences (India)

    Unknown

    sed vehicular traffic and use of fertilizers and pesticides in agriculture have resulted in increased metal contamina- tion in our environment. Not only the occupationally ex- posed workers (high-risk population group) but the community at large (low-risk population group) may suf- fer due to increased metal pollutants in the ...

  3. Rape prevention

    Science.gov (United States)

    Date rape - prevention; Sexual assault - prevention ... Centers for Disease Control and Prevention website. Sexual assault and abuse and STDs. In: 2015 sexually transmitted diseases treatment guidelines 2015. www.cdc.gov/std/tg2015/sexual- ...

  4. Dengue Prevention

    Science.gov (United States)

    ... Address What's this? Submit What's this? Submit Button Prevention Recommend on Facebook Tweet Share Compartir This photograph ... medications to treat a dengue infection. This makes prevention the most important step, and prevention means avoiding ...

  5. The Effect of Season on the Metabolic Profile of the European Clam Ruditapes decussatus as Studied by 1H-NMR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Violetta Aru

    2017-07-01

    Full Text Available In this study, the metabolome of Ruditapes decussatus, an economically and ecologically important marine bivalve species widely distributed in the Mediterranean region, was characterized by using proton Nuclear Magnetic Resonance (1H-NMR spectroscopy. Significant seasonal variations in the content of carbohydrates and free amino acids were observed. The relative amounts of alanine and glycine were found to exhibit the same seasonal pattern as the temperature and salinity at the harvesting site. Several putative sex-specific biomarkers were also discovered. Substantial differences were found for alanine and glycine, whose relative amounts were higher in males, while acetoacetate, choline and phosphocholine were more abundant in female clams. These findings reveal novel insights into the baseline metabolism of the European clam and represent a step forward towards a comprehensive metabolic characterization of the species. Besides providing a holistic view on the prominent nutritional components, the characterization of the metabolome of this bivalve represents an important prerequisite for elucidating the underlying metabolic pathways behind the environment-organism interactions.

  6. Effects of Freshwater Clam Extract Supplementation on Time to Exhaustion, Muscle Damage, Pro/Anti-Inflammatory Cytokines, and Liver Injury in Rats after Exhaustive Exercise

    Directory of Open Access Journals (Sweden)

    Kuang-Wen Liao

    2013-03-01

    Full Text Available The potent anti-inflammatory activities and tissue-protective effects of freshwater clams (Corbicula fluminea have been well reported. The aim of this study was to determine the effects of freshwater clam extract (FCE supplementation on time to exhaustion, muscle damage, pro- and anti-inflammatory cytokines, and liver injury in rats after exhaustive exercise. Thirty-two rats were divided into four groups: sedentary control (SC; SC group with FCE supplementation (SC+FCE; exhaustive exercise (E; and E group with FCE supplementation (E+FCE. The SC+FCE and E+FCE groups were treated with gavage administration of 20 mg/kg for seven consecutive days. Blood samples were collected for the evaluation of biochemical parameters. The cytokine levels of TNF-α and IL-10 were also examined. Twenty-four hours after exhaustive exercise, the rat livers were removed for H & E staining. The FCE supplementation could extend the time to exhaustion in exercised rats. The levels of CPK, LDH, AST, ALT, lactate, TNF-α and H & E stains of the liver injury were significantly decreased in the E+FCE group, but the blood glucose and IL-10 were significantly higher in comparison with the E group. This study suggests that FCE supplementation may improve endurance performance and reduce exercise-induced muscle damage, inflammatory stress and liver injury.

  7. Induction of DNA strand breaks in the mussel (Mytilus trossulus) and clam (Protothaca staminea) following chronic field exposure to polycyclic aromatic hydrocarbons from the Exxon Valdez spill.

    Science.gov (United States)

    Thomas, Robert E; Lindeberg, Mandy; Harris, Patricia M; Rice, Stanley D

    2007-06-01

    In 2002, 13 years after the Exxon Valdez spill, mussels and clams were examined for lingering oil exposure and damage. Known oil patches were sampled at four locations, and compared to nearby reference areas (same bay), and were also compared to "hot reference" sites to verify the methods used (Cordova harbor and fresh diesel spill at Port Chalmers). Passive samplers deployed for a month at the sites, along with tissue samples, confirmed that the oiled sites were oiled (fingerprinting back to Exxon Valdez oil) and that reference sites were clean. The highest PAH loads were detected in sub-surface interstitial waters at oiled sites. Exposure at the surface was generally low level, and probably intermittent. DNA damage was assessed in blood cells using sensitive comet analyses. DNA strand breakage was detected in both mussels and clams, with the highest level of damage detected at "hot reference" sites of Cordova harbor and Port Chalmers. Bioavailability and DNA damage at the oiled sties was low, indicating there has been substantial progress in recovery from the spill 13 years before, yet low level bioavailability and damage were still detectable.

  8. Relationship between two androgenetic clam species, Corbicula leana and Corbicula fluminea, inferred from mitochondrial cytochrome b and nuclear 28S rRNA markers.

    Science.gov (United States)

    Komaru, Akira; Yamada, Mitsuya; Houki, Shouji

    2013-05-01

    Two shell color types, yellow (type I) and brown (type II), of hermaphrodite Corbicula fluminea clams from Ritto, Shiga Prefecture, Japan, are sympatric with both male and hermaphrodite Corbicula leana. In the present study, the mitochondrial DNA (mtDNA) cytochrome b and nuclear 28S rRNA genes of C. fluminea were sequenced to construct a haplotype network in order to investigate the genetic relationship with C. leana. Ninety C. fluminea samples revealed only two cytb haplotypes; the majority (97.8%) were CB7, while the remainder were CB1. In C. leana, only CB1 was detected in hermaphrodites, but both CB1 and CB7 were detected in males. Nuclear 28S rRNA haplotypes of C. fluminea type I individuals were divergent from those of hermaphrodite C. leana. However, C. fluminea type I clams shared haplotypes with male C. leana individuals, whereas C. fluminea type II individuals shared haplotypes with both hermaphrodite and male C. leana samples. These results suggest that it may be difficult to define a clear genetic border between these species.

  9. Development of Vibrio spp. infection resistance related SNP markers using multiplex SNaPshot genotyping method in the clam Meretrix meretrix.

    Science.gov (United States)

    Nie, Qing; Yue, Xin; Liu, Baozhong

    2015-04-01

    The clam Meretrix meretrix is a commercially important mollusc species in the coastal areas of South and Southeast Asia. In the present study, large-scale SNPs were genotyped by the Multiplex SNaPshot genotyping method among the stocks of M. meretrix with different Vibrio spp. infection resistance profile. Firstly, the AUTOSNP software was applied to mine SNPs from M. meretrix transcriptome, and 323 SNP loci (including 120 indels) located on 64 contigs were selected based on Uniprot-GO associations. Then, 38 polymorphic SNP loci located on 15 contigs were genotyped successfully in the clam stocks with different resistance to Vibrio parahaemolyticus infection (11-R and 11-S groups). Pearson's Chi-square test was applied to compare the allele and genotype frequency distributions of the SNPs between the different stocks, and seven SNP markers located on three contigs were found to be associated with V. parahaemolyticus infection resistance trait. Haplotype-association analysis showed that six haplotypes had significantly different frequency distributions in 11-S and 11-R (P Vibrio harveyi infection, four out of the seven selected SNPs had significantly different distributions (P Vibrio spp. infection resistance. Sequence alignments and annotations indicated that the contigs containing the associated SNPs had high similarity to the immune related genes. All these results would be useful for the future marker-assisted selection of M. meretrix strains with high Vibrio spp. infection resistance. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Mortality event involving larvae of the carpet shell clam Ruditapes decussatus in a hatchery: isolation of the pathogen Vibrio tubiashii subsp. europaeus.

    Science.gov (United States)

    Dubert, J; Aranda-Burgos, J A; Ojea, J; Barja, J L; Prado, S

    2017-09-01

    Diseases caused by bacteria belonging to the genus Vibrio are a common, as yet unresolved, cause of mortality in shellfish hatcheries. In this study, we report the results of routine microbiological monitoring of larval cultures of the carpet shell clam Ruditapes decussatus in a hatchery in Galicia (NW Spain). Previous episodes of mortality with signs similar to those of vibriosis affecting other species in the installation indicated the possibility of bacterial infection and led to division of the culture at the early D-veliger larval stage. One batch was cultured under routine conditions, and the other was experimentally treated with antibiotic (chloramphenicol). Differences in larval survival were assessed, and culturable bacterial population in clams and sea water was evaluated, with particular attention given to vibrios. Severe mortalities were recorded from the first stages of culture onwards. The pathogen Vibrio tubiashii subsp. europaeus was detected in both batches, mainly associated with larvae. Moreover, initial detection of the pathogen in the eggs suggested the vertical transmission from broodstock as a possible source. Experimental use of antibiotic reduced the presence and diversity of vibrios in sea water, but proved inefficient in controlling vibrios associated with larvae from early stages and it did not stop mortalities. © 2017 John Wiley & Sons Ltd.

  11. Plague Prevention

    Science.gov (United States)

    ... Healthcare Professionals Clinicians Public Health Officials Veterinarians Prevention History of Plague Resources FAQ Prevention Recommend on Facebook Tweet Share Compartir Reduce rodent habitat around your ...

  12. Neuroenzymatic activity and physiological energetics in Manila clam, Ruditapes philippinarum, during short-term sublethal exposure to harmful alga, Heterocapsa circularisquama.

    Science.gov (United States)

    Basti, Leila; Nagai, Satoshi; Watanabe, Satoshi; Oda, Tatsuya; Tanaka, Yuji

    2016-07-01

    The harmful alga, Heterocapsa circularisquama, causes recurrent mortalities of bivalve molluscs in Japan, with demonstrated hemolysis and cytotoxicity in rabbit erythrocytes, HeLa cells, and bivalve tissues. Nonetheless, the effects of exposure to sublethal cell densities on the physiological energetics of bivalves have not been investigated, nor the potential involvement of neurotoxicity. In the present study, two sets of experiments were conducted with adult clams, Ruditapes philippinarum. In the first set, the clearance rate (CR), respiration rate (RR), absorption efficiency (AE), ingestion rate (IR), and absorption rate (AR) were examined in clams exposed to H. circularisquama to quantify the scope for growth (SFG) as an indicative of the bioenergetic status of clams (5, 50, 2.5×10(2), and 5×10(2)cellsml(-1); under 15°C and 20°C). In the second set, the activity of the biomarker of neurotoxic exposure, acetylcholinesterase (AChE), was monitored following 3, 6, 24, and 48h of exposure (5, 50, 5×10(2), and 10(3)cellsml(-1), at 20°C) in gills of R. philippinarum, and compared to that in Mediterranean mussels, Mytilus galloprovincialis; a species also affected by H. circualrisquama and in which AChE activity was more extensively studied. At 15°C, CR, IR, and AR were decreased for exposures to 50-5×10(2) cells ml(-1) resulting in a significant decrease in the absorbed energy (A), and a significant decrease in SFG at 5×10(2)cellsml(-1). At 20°C, AE was null for exposures to 2.5×10(2) and 5×10(2)cellsml(-1). RR was decreased at 2.5×10(2) and 5×10(2)cellsml(-1), CR, IR, and AR were decreased at 5-5×10(2)cellsml(-1), and the AE was null for 2.5×10(2)-5×10(2)cellsml(-1) resulting in a significant decrease in the respired energy (R), but mainly in (A) especially at 2.5×10(2) and 5×10(2)cellsml(-1) decreasing the SFG over the entire range of cell density with negative values for 2.5×10(2) and 5×10(2)cellsml(-1). The activity of AChE in both clams and

  13. Paralytic shellfish toxins in the chocolata clam, Megapitaria squalida (Bivalvia: Veneridae, in Bahía de La Paz, Gulf of California

    Directory of Open Access Journals (Sweden)

    I Gárate-Lizárraga

    2004-09-01

    Full Text Available Occurrence and toxic profiles of paralytic shellfish toxins (PST in the chocolata clam Megapitaria squalida were investigated. From December 2001 to December 2002, 25 clams were obtained monthly from Bahía de La Paz, Gulf of California. Additionally, net (20 µm and bottle phytoplankton samples were also collected to identify toxic species. Toxins were analyzed by HPLC with post-column oxidation and fluorescence detection. Toxicity in the clam was low and varied from 0.14 to 5.46 µg/STXeq/100 g. Toxicity was detected in December, March, April, June, and August. Toxin profile was composed mainly by STX, GTX2, GTX3, dcGTX2, dcGTX3, C2, dcSTX and B1. Gymnodinium catenatum was the only PST-producing dinoflagellate identified in the phytoplankton samples throughout the study period. G. catenatum was observed mainly in net samples from December 2001 to December 2002; however, in bottle samples, G. catenatum was only observed in five months. Highest abundance (2 600 cells l-1 was observed in March and the lowest (160 cells l-1 in June. G. catenatum mainly formed two-cell chains and rarely four or eight. The presence of PST in net phytoplankton samples support the fact that G. catenatum is the main source of PST in the clams. This study represents the first report of PST toxins in the chocolata clam from Bahía de La PazSe investigó la ocurrencia así como los perfiles de toxinas paralíticas (PST en la almeja chocolata Megapitaria squalida (Sowerby, 1835, de la cual se recolectaron mensualmente 25 ejemplares de diciembre del 2001 a diciembre del 2000 en La Bahía de La Paz, Golfo de California. Simultáneamente, se obtuvieron muestras de fitoplancton de botella y de red (20 µM para identificar especies tóxicas, así como para detectar la presencia de toxinas paralíticas. Las toxinas se analizaron por HPLC con una oxidación post-columna y detección fluorescente. La toxicidad en las almejas fue baja y varió de 0.14 a 5.46 µg/STXeq/100 g y se

  14. Evaluación de la tasa de aclaración de la almeja dulceacuícola Anodontites tortolis en un medio con coliformes Escherichia coli Clearance rate of faecal coliforms by netropical freshwater clam

    Directory of Open Access Journals (Sweden)

    Juan René Mallama Leyton

    2011-01-01

    Full Text Available En condiciones de laboratorio se evaluón acute; la eficiencia de la almeja de agua dulce (Anodontites tortolis) para disminuir la carga de coliformes fecales (Escherichia coli) determinada mediante filtración en membrana por 8 horas. El experimento se diseñó con dos tratamientos (densidades de seis (T1) y ocho almejas (T2) más un control) con tres replicaciones. Se encontraron diferencias significativas (PUnder laboratory conditions the efficiency of the freshwater clam Anodontites tortolis to diminish the quantity of faecal coliforms, determined by the membrane filtration method during eight hours was evaluated. The experiment was design with two treatments (two densities of six (T1) and eight clams (T2) and a control) and three replications. Statistical significant differences (P<0.05) according to the Kruskal-Wallis test for the clearance rates were found. The highest levels of remotion of E. coli belonged to the treatment in which there was the highest number of individuals. The clearance rate of the clams varied between 0.47 and 3.80 l.h-1.ind-1 which is reported in the literature. Removal levels showing A. tortolis suggest that this clam can be used as a biological resource for the treatment of the tertiary waters contaminated with faecal coliform bacteria.

  15. A Comparative Study of Clam and Squid. Biting Flies of the Coastal Region. Diatoms: Nature's Aquatic Gems. Learning Experiences for Coastal and Oceanic Awareness Studies, Nos. 227, 231, 232. [Project COAST].

    Science.gov (United States)

    Delaware Univ., Newark. Coll. of Education.

    Included are three units related to coastal and oceanic awareness. The units are: (1) A Comparative Study of Clam and Squid; (2) Biting Flies of the Coastal Region; and (3) Diatoms: Nature's Aquatic Gems. All three units were designed for secondary school students. Each unit contains teacher background materials, student activity materials,…

  16. Embrionary and larval development of the marine clam Tivela mactroides (Bivalvia:Veneridaein Zulia State,Venezuela

    Directory of Open Access Journals (Sweden)

    Yinett M Reverol

    2004-12-01

    Full Text Available The marine clam,Tivela mactroides ,from Caño Sagua beach,Venezuela,was spawned and reared under laboratory conditions to monitor its early development.Spawning was spontaneous but in some cases it had to be induced by the additon of eggs and sperm.After fertilization,the embryonic development occurred at 5 hr approximately. Trochophore larvae were observed between eight and ten hours later.Straight-hinged veliger stage appeared 15 hr after fertilization.Transition from veliger stage to the umbo stage occurred about eight days after fertilization.Pediveliger stage was observed 22 days after fertilization.Metamorphosis of T.mactroides was not successful under our laboratory conditions;probably the bacterial contamination and subsequent mortalities were important factors constraining the final phase of the larval cycle.However,in a few cases young individuals were observed.We suspect that this was due to unfavorable conditions (e.g.:bacterial contamination, unsuitable food availability,etc.and the broad variation in developmental times,suggesting that these stages might be particularly sensitive to environmental changes.These results may not necessarily reflect what happens under natural conditions.Rev.Biol.Trop.52(4:903-909.Epub 2005 Jun 24.La almeja Tivela mactroides ,de la playa Caño Sagua, Venezuela,fue desovada y cultivada bajo condiciones de laboratorio,monitoreando su desarrollo embrionario y larvario.El desove fue espontáneo,sin embargo,en algunos casos se indujo adicionando óvulos y espermatozoides. El desarrollo embrionario se produjo en cinco horas, aproximadamente.La larva trocófora fue observada a las diez horas,mientras que la prodisoconcha aparece a las 15 horas después de la fertilización.La larva disoconcha aparece ocho días después de la fecundación y la veliconcha,aproximadamente a los 20 días.La metamorfosis de T.mactroides no fue satisfactoria bajo estas condiciones, ya que la contaminación bacterial fue uno de los

  17. Subcellular partitioning profiles and metallothionein levels in indigenous clams Moerella iridescens from a metal-impacted coastal bay

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zaosheng, E-mail: zswang@iue.ac.cn [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Boulevard, Xiamen 361021 (China); State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Feng, Chenglian; Ye, Chun [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Wang, Youshao [State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301 (China); Yan, Changzhou, E-mail: czyan@iue.ac.cn [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Boulevard, Xiamen 361021 (China); Li, Rui; Yan, Yijun; Chi, Qiaoqiao [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Boulevard, Xiamen 361021 (China)

    2016-07-15

    Highlights: • Subcellular partitioning profile of metals were investigated in biomonitor organism. • Cu, Zn and Cd levels in main fraction of HSP increase along accumulation gradients. • Despite MTs as the major binding pool, detoxification of Cd and Pb was incomplete. • Induced MTs were sequentially correlated with Cu, Zn and Cd levels in HSP fraction. • Intracellular metal fates highlighted the metabolic availability within organism. - Abstract: In this study, the effect of environmental metal exposure on the accumulation and subcellular distribution of metals in the digestive gland of clams with special emphasis on metallothioneins (MTs) was investigated. Specimens of indigenous Moerella iridescens were collected from different natural habitats in Maluan Bay (China), characterized by varying levels of metal contamination. The digestive glands were excised, homogenized and six subcellular fractions were separated by differential centrifugation procedures and analyzed for their Cu, Zn, Cd and Pb contents. MTs were quantified independently by spectrophotometric measurements of thiols. Site-specific differences were observed in total metal concentrations in the tissues, correlating well with variable environmental metal concentrations and reflecting the gradient trends in metal contamination. Concentrations of the non-essential Cd and Pb were more responsive to environmental exposure gradients than were tissue concentrations of the essential metals, Cu and Zn. Subcellular partitioning profiles for Cu, Zn and Cd were relatively similar, with the heat-stable protein (HSP) fraction as the dominant metal-binding compartment, whereas for Pb this fraction was much less important. The variations in proportions and concentrations of metals in this fraction along with the metal bioaccumulation gradients suggested that the induced MTs play an important role in metal homeostasis and detoxification for M. iridescens in the metal-contaminated bay. Nevertheless

  18. Effects of temperature and salinity on metabolic rate of the Asiatic clam Corbicula fluminea (Müller, 1774).

    Science.gov (United States)

    Xiao, Bai-Cai; Li, Er-Chao; Du, Zhen-Yu; Jiang, Run-Lan; Chen, Li-Qiao; Yu, Na

    2014-01-01

    The effects of temperature and salinity on the metabolism of the Asiatic clam Corbicula fluminea (mollusca, Lamellibranchia) were studied experimentally. Firstly, three indexes of basal metabolism (oxygen consumption rate, OCR; ammonia excretion rate, AER; and CO2 emission rate, CER), patterns of diurnal rhythm and O: N ratios were measured for three size ranges (large: h = 25.54 ± 1.96 mm, medium: h = 22.07 ± 1.33 mm and small: h = 17.70 ± 1.43 mm) at two salinities (0.3‰ and 1.8‰). The results showed that: (1) three indexes decreased with increasing body size. (2) no significant difference was found between two salinities for the O: N ratios of the small and large size, but a significant difference was found for the medium-sized one; (3) however, there were similar and distinct diurnal rhythms of metabolic rate at two salinities over a 24 hour period in three size C. fluminea. N ratios and Q10 (temperature coefficient) of small-sized C. fluminea were measured across five water temperatures (4, 11, 18, 25 and 32°C) and two salinities (0.3‰ and 1.8‰) in the following experiments. Our results of the small C. fluminea were as follows: there was no significant difference in the O: N ratios among the five temperatures and two salinity treatments; and no significant difference of three indexes between both salinity levels were observed at same temperature controlled; and three indexes increased significantly with increasing temperature from 4°C to 25°C, while no significant difference was observed in the 25-32°C range; and the highest Q10 coefficients (Q10 = 1.825 at salinity of 0.3‰ and Q10 = 1.683 at salinity of 1.8‰) were observed at the 18-25°C temperature increase, and the low values were found in the 4-11°C, 11-18°C and 25-32°C interval. It indicates that there is not a synergetic effect of our temperature and salinity on the metabolic rate of small C. fluminea, and a temperature of 18-25°C may represent an optimum adequate metabolic

  19. High resolution climate records from modern and last interglacial period derived from giant clam shells (Tridacnidae) from Sulawesi, Indonesia.

    Science.gov (United States)

    Arias Ruiz, Camilo; Elliot, Mary; Bezos, Antoine; Padoja, Kevin; Husson, Laurent; Michel, Elisabeth; La, Carole

    2017-04-01

    We studied Tridacnidae giant clams as environmental archives to reconstruct climate evolution in a region characterized by major ocean-atmosphere exchange on seasonal and inter-annual timescales: the Sulawesi archipelago. Using environmental proxies (18O and trace elements) we present reconstructions of inter-annual climate change derived from modern and past interglacial period (MIS 5). For fossil archive, U-Th ages were obtained from fossil coral samples from the same paleo-reef of Tridacna samples, because these bivalves exhibit an open system behavior in U-Th series. Comparison of a 18O profile derived from a 6 year old modern T. squamosa (2006-2012) and a predicted 18O profile derived from local temperature and salinity records confirms the isotopic equilibrium in shell deposition. The strong sea surface temperature (SST) anomaly of 2010 related to a strong La Niña was also recorded in the shell 18O signal. The modern 18O record presents a mean seasonal range of 0.5 ± 0.1 ‰. Additional trace element analyses show that Mg/Ca and Sr/Ca are also temperature dependent in this species and appear less affected by changes in salinity/rainfall. Finally, Ba/Ca ratio appears to reflect both primary production related to coastal up-welling during the dry season, and continental run-off during the wet season. Trace element profiles also exhibit strong anomalies reflecting changes in local hydrography related to the 2010 La Niña. The ages of the Tridacna fossils derived from U-Th dating are around last interglacial MIS-5 period. 18O records derived from a fossil Tridacna gigas specimen provide a time-window of 14 years. The record shows a reduced mean seasonal range of 18O of around 0.4±0.2 ‰. Absence of Ba/Ca peaks during the wet season suggest a weakened monsoon rainfall activity, but the presence during the dry season suggests a persistent seasonal up-welling at this time. Our study illustrates the usefulness of Tridacnidae fossils in

  20. Preventing Addiction.

    Science.gov (United States)

    Moore, Susan Fordney

    The purpose of this paper is to provide the beginning counselor with an overview of prevention concepts. Prevention is a relatively new emphasis in community efforts to stem the rising costs of substance abuse and other high-risk behaviors. The paper discusses agent, host, and environmental prevention models and how they relate to causal theories…

  1. A Freshwater clam (Corbicula fluminea) extract reduces cholesterol level and hepatic lipids in normal rats and xenobiotics-induced hypercholesterolemic rats.

    Science.gov (United States)

    Chijimatsu, Takeshi; Tatsuguchi, Iwao; Oda, Hiroaki; Mochizuki, Satoshi

    2009-04-22

    We investigated whether a freshwater clam (Corbicula fluminea) extract (FCE) could improve cholesterol metabolism and hepatic lipids accumulation in rats fed xenobiotics such as chloretone. Feeding chloretone resulted in hypercholesterolemia and fatty liver. An increase in serum cholesterol, high density lipoproteins (HDL) in particular, after intake of chloretone was observed. Serum cholesterol was decreased by supplementation with FCE. Accumulation of the hepatic lipids including triacylglycerol, cholesterol, and phospholipid was significantly suppressed by supplementation with FCE. The excretion of neutral and acidic sterols into the feces was enhanced by FCE. The hepatic gene expression of cholesterol 7alpha-hydroxylase was enhanced in rats fed a FCE-containing diet. Apolipoprotein A-I gene expression in the liver, which is a major apolipoprotein of HDL, was suppressed by FCE. These results demonstrated that FCE reduced cholesterol level and hepatic lipids in normal rats and hypercholesterolemic rats fed chloretone.

  2. A simple allometric diffusion-based biokinetic model to predict Cu(II) uptake across gills of freshwater clam Corbicula fluminea.

    Science.gov (United States)

    Chen, W-Y; Lin, C-M; Ju, Y-R; Liao, C-M

    2010-06-01

    The purpose of this study was to link Fick's type mass transfer and biokinetics together with Michaelis-Menten kinetics to arrive at a simple predictive framework for quantifying biouptake mechanisms in gills of freshwater clam Corbicula fluminea exposed to Cu(II). A diffusion-based Cu(II) influx and permeability can be calculated using physiological and allometric-related parameters. Simulations indicate that Cu(II) bioconcentration factor of gills was 42. Estimated steady-state Cu(II) gill uptake influx and permeability were 0.097 nmol cm(-2) s(-1) and 0.48 cm s(-1), respectively. The proposed simple allometric diffusion-based biokinetic model meets the need for describing nonequilibrium aspects of biouptake mechanisms in bivalve gills.

  3. Effects of the human antiepileptic drug carbamazepine on the behavior, biomarkers, and heat shock proteins in the Asian clam Corbicula fluminea.

    Science.gov (United States)

    Chen, Huihui; Zha, Jinmiao; Liang, Xuefang; Li, Jiasu; Wang, Zijian

    2014-10-01

    Carbamazepine (CBZ), an anticonvulsant and mood-stabilizing pharmaceutical, is a widespread contaminant in aquatic environments. In this study, the effects of chronic exposure to environmentally relevant CBZ concentrations were investigated in freshwater clams Corbicula fluminea. Adult C. fluminea were exposed to 0.5, 5, and 50 μg/L of CBZ for 30 days, after which siphoning behavior (filtration rates), biomarker levels, and heat shock protein expression were measured. The filtration rates were significantly decreased (pfluminea health. Superoxide dismutase (SOD) and glutathione reductase (GR) activities were decreased, and catalase (CAT) activity and malondialdehyde (MDA) content were increased in the gills and digestive gland, suggesting that CBZ induced an oxidative effect. The levels of Hsp22, Hsp40, and Hsp70 mRNAs were also markedly induced after 5 or 50 μg/L CBZ treatment (pfluminea tissue at the molecular and protein level. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Dietary freshwater clam (Corbicula fluminea) extract suppresses accumulation of hepatic lipids and increases in serum cholesterol and aminotransferase activities induced by dietary chloretone in rats.

    Science.gov (United States)

    Chijimatsu, Takeshi; Umeki, Miki; Kobayashi, Satoru; Kataoka, Yutaro; Yamada, Koji; Oda, Hiroaki; Mochizuki, Satoshi

    2015-01-01

    We investigated the ameliorative effect of freshwater clam extract (FCE) on fatty liver, hypercholesterolemia, and liver injury in rats exposed to chloretone. Furthermore, we examined the effects of major FCE components (fat and protein fractions) to determine the active components in FCE. Chloretone increased serum aminotransferase activities and led to hepatic lipid accumulation. Serum aminotransferase activities and hepatic lipid content were lower in rats fed total FCE or fat/protein fractions of FCE. Expression of fatty acid synthase and fatty acid desaturase genes was upregulated by chloretone. Total FCE and fat/protein fractions of FCE suppressed the increase in gene expression involved in fatty acid synthesis. Serum cholesterol levels increased twofold upon chloretone exposure. Total FCE or fat/protein fractions of FCE showed hypocholesterolemic effects in rats with hypercholesterolemia induced by chloretone. These suggest that FCE contains at least two active components against fatty liver, hypercholesterolemia, and liver injury in rats exposed to chloretone.

  5. Effect of okadaic acid on carpet shell clam (Ruditapes decussatus) haemocytes by in vitro exposure and harmful algal bloom simulation assays.

    Science.gov (United States)

    Prado-Alvarez, Maria; Flórez-Barrós, Fernanda; Méndez, Josefina; Fernandez-Tajes, Juan

    2013-06-01

    Okadaic acid (OA), produced by dinoflagellates during harmful algal blooms (HAB), belongs to the Diarrheic Shellfish Poisoning toxins that cause gastrointestinal symptoms in humans after consumption. In the present work, Ruditapes decussatus haemocytes were selected to evaluate the effect of OA on cell viability, enzymatic status and immune capacity through the measure by flow cytometry of apoptosis-cell death, non-specific esterase activity and phagocytosis. In order to compare different exposure conditions, two experiments were developed: in vitro exposure to OA and HAB simulation by feeding clams with the OA producer, Prorocentrum lima. Apoptosis was not OA dose-dependent and cell death increased in both assays. Phagocytosis of latex beads and esterase activity decreased in haemocytes incubated with OA. In contrast, esterases increased during the feeding with P. lima. Our results showed that OA and the simulated HAB caused damages on haemocyte functions and viability.

  6. Expression of genes involved in the uptake of inorganic carbon in the gill of a deep-sea vesicomyid clam harboring intracellular thioautotrophic bacteria.

    Science.gov (United States)

    Hongo, Yuki; Ikuta, Tetsuro; Takaki, Yoshihiro; Shimamura, Shigeru; Shigenobu, Shuji; Maruyama, Tadashi; Yoshida, Takao

    2016-07-10

    Deep-sea vesicomyid clams, including the genus Phreagena (formerly Calyptogena), harbor thioautotrophic bacterial symbionts in the host symbiosome, which consists of cytoplasmic vacuoles in gill epithelial cells called bacteriocytes. The symbiont requires inorganic carbon (Ci), such as CO2, HCO3(-), and CO3(2-), to synthesize organic compounds, which are utilized by the host clam. The dominant Ci in seawater is HCO3(-), which is impermeable to cell membranes. Within the bacteriocyte, cytoplasmic carbonic anhydrase (CA) from the host, which catalyzes the inter-conversion between CO2 and HCO3(-), has been shown to be abundant and is thought to supply intracellular CO2 to symbionts in the symbiosome. However, the mechanism of Ci uptake by the host gill from seawater is poorly understood. To elucidate the influx pathway of Ci into the bacteriocyte, we isolated the genes related to Ci uptake via the pyrosequencing of cDNA from the gill of Phreagena okutanii, and investigated their expression patterns. Using phylogenetic and amino acid sequence analyses, three solute carrier family 4 (SLC4) bicarbonate transporters (slc4co1, slc4co2, and slc4co4) and two membrane-associated CAs (mcaco1 and mcaco2) were identified as candidate genes for Ci uptake. In an in situ hybridization analysis of gill sections, the expression of mcaco1 and mcaco2 was detected in the bacteriocytes and asymbiotic non-ciliated cells, respectively, and the expression of slc4co1 and slc4co2 was detected in the asymbiotic cells, including the intermediate cells of the inner area and the non-ciliated cells of the external area. Although subcellular localizations of the products of these genes have not been fully elucidated, they may play an important role in the uptake of Ci into the bacteriocytes. These findings will improve our understanding of the Ci transport system in the symbiotic relationships of chemosynthetic bivalves. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Can the hemoglobin characteristics of vesicomyid clam species influence their distribution in deep-sea sulfide-rich sediments? A case study in the Angola Basin

    Science.gov (United States)

    Decker, C.; Zorn, N.; Le Bruchec, J.; Caprais, J. C.; Potier, N.; Leize-Wagner, E.; Lallier, F. H.; Olu, K.; Andersen, A. C.

    2017-08-01

    Vesicomyids live in endosymbiosis with sulfur-oxidizing bacteria and therefore need hydrogen sulfide to survive. They can nevertheless live in a wide range of sulfide and oxygen levels and depths, which may explain the exceptional diversity of this clam family in deep-sea habitats. In the Gulf of Guinea, nine species of vesicomyid clams are known to live in cold-seep areas with pockmarks from 600 to 3200 m deep, as well as in the organic-rich sediments of the Congo deep-sea fan at 5000 m deep. Our previous study showed that two species living in a giant pockmark have different oxygen carriers, suggesting different adaptations to hypoxia. Here, we studied the hemoglobin structure and oxygen affinity in three other species, Calyptogena valdiviae, Elenaconcha guiness and Abyssogena southwardae to determine whether the characteristics of their oxygen carriers contribute to their distribution in sulfide-rich sediments at a regional scale. Documenting pairwise species associations in various proportions, we give a semi-quantitative account of their local distribution and oxygen and sulfide measurements at seven sites. Mass spectrometry showed that each vesicomyid species has four intracellular monomeric hemoglobin molecules of 15-16 kDa, all differing in their molecular mass. As expected, the monomers showed no cooperativity in oxygen binding. Their oxygen affinities were very high (below 1 Torr), but differed significantly. C. valdiviae had the highest affinity and was dominant in the Harp pockmark, the site with the lowest oxygen content (half the value of fully oxygenated water). A. southwardae dominated in the Congo Lobe area, the site with the deepest sulfides. We discuss how hemoglobin may favor an active, vertical distribution of vesicomyids in sulfide-rich sediments.

  8. Microhabitat and biology of Sphaerium striatinum in a central New York stream

    Science.gov (United States)

    Dittman, Dawn E.; Johnson, James H.; Nack, Christopher C.

    2018-01-01

    In many lotic systems, drastic declines in freshwater bivalve populations, including fingernail clams (Sphaeriidae), have created concerns about biodiversity and future ecosystem services. We examined the local occurrence of the historically common fingernail clam, Sphaerium striatinum, in a central New York stream. We sampled the density of sphaeriids and measured the associated habitat variables (substrate, depth, water flow) to test within-stream multivariate benthic microhabitat association. Size distribution, density, and diel feeding periodicity were measured as focal aspects of fingernail clam biology and ecology. S. striatinum tended to be found in microhabitats that had harder substrates and faster flow. The Labrador Creek fingernail clam local population had positive indicators (size distribution, density). There was significant diel periodicity in feeding behavior. The clams fed most actively during the 0400–0800 h periods. This kind of behavioral periodicity can indicate a significant ecological interaction between predators and bivalve prey. Increased understanding of the behavioral ecology of small native freshwater bivalves in an unimpacted headwater stream is a fundamental building block for development of overall ecological conservation goals for freshwater bivalves and their lotic habitats.

  9. Prevention: Exercise

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    Full Text Available ... Steroid Injections Lumbar Zygapophysical (Facet) Joint Injections PREVENTION Lifestyle Choices 10 Tips for a Healthy Back Smoking Weight Patient Safety Exercise Strengthening Strengthen ...

  10. Prevention: Exercise

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    Full Text Available ... Injections PREVENTION Lifestyle Choices 10 Tips for a Healthy Back Smoking Weight Patient Safety Exercise Strengthening Strengthen Your Core! Stretching/Flexibility Aerobic Exercise ...

  11. Prevention: Exercise

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    Full Text Available ... Watchful Waiting and Education Injection Treatments for Spinal Pain Epidural Steroid Injections Lumbar Zygapophysical (Facet) Joint Injections PREVENTION Lifestyle Choices 10 ...

  12. Evaluation of toxicological effects induced by tributyltin in clam Ruditapes decussatus using high-resolution magic angle spinning nuclear magnetic resonance spectroscopy: Study of metabolic responses in heart tissue and detection of a novel metabolite

    Directory of Open Access Journals (Sweden)

    H. Hanana

    2014-01-01

    The main finding of this study was the appearance of an original metabolite after TBT treatment likely N-glycine-N′-alanine. It is the first time that this molecule has been identified as a natural compound. Its exact role is unknown and remains to be elucidated. We suppose that its formation could play an important role in clam defense response by attenuating Ca2+ dependent cell death induced by TBT. Therefore this compound could be a promising biomarker for TBT exposure.

  13. Poison Prevention

    Science.gov (United States)

    ... Prevention Listen Español Text Size Email Print Share Poison Prevention Page Content Article Body Post the Poison Help number 1-800-222-1222 on the ... or empty container of a toxic substance, call Poison Help immediately. More than a million American children ...

  14. Water-quality assessment of the Albemarle-Pamlico drainage basin, North Carolina and Virginia; trace elements in Asiatic clam (Corbicula fluminea) soft tissues and redbreast sunfish (Lepomis auritus) livers, 1992-93

    Science.gov (United States)

    Ruhl, P.M.; Smith, K.E.

    1996-01-01

    The analysis of potential contaminants in biological tissues is an important part of many water-quality assessment programs, including the National Water-Quality Assessment (NAWQA) Program. Tissue analyses often are used to provide information about (1) direct threats to ecosystem integrity, and (2) the occurrence and distribution of potential contaminants in the environment. During 1992-93, trace elements in Asiatic clam (Corbicula fluminea) soft tissues and redbreast sunfish (Lepomis auritus) livers were analyzed to obtain information about the occurrence and distribution of trace element contaminants in the Albemarle-Pamlico Drainage Basin of North Carolina and Virginia. The investigation was conducted as part of the NAWQA Program. All but 3 of the 22 trace elements that were analyzed were detected. Although all 10 of the U.S. Environmental Protection Agency (U.S. EPA) priority pollutants were detected in the tissues sampled, they were present in relatively low concentrations. Concentrations of U.S. EPA priority pollutants in Asiatic clams collected in the Albemarle-Pamlico Drainage Basin are similar to concentrations observed in other NAWQA study units in the southeastern United States. Mercury (a U.S. EPA priority pollutant) was widely detected, being present in 29 of 30 tissue samples, but concentrations did not exceed the FDA action level for mercury of a risk-based screening value for the general public. Mercury concentrations in Asiatic clams were similar to concentrations in other NAWQA study areas in the Southeast.

  15. Preventive analgesia

    DEFF Research Database (Denmark)

    Dahl, Jørgen B; Kehlet, Henrik

    2011-01-01

    This paper will discuss the concepts of pre-emptive and preventive analgesia in acute and persistent postsurgical pain, based on the most recent experimental and clinical literature, with a special focus on injury-induced central sensitization and the development from acute to chronic pain. Recent...... of preventive analgesia for persistent postoperative pain are promising. However, clinicians must be aware of the demands for improved design of their clinical studies in order to get more conclusive answers regarding the different avenues for intervention. Summary: The concept of preventive analgesia is still...

  16. Dynamics and chemistry of vortex remnants in late Arctic spring 1997 and 2000: Simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS

    Directory of Open Access Journals (Sweden)

    P. Konopka

    2003-01-01

    Full Text Available High-resolution simulations of the chemical composition of the Arctic stratosphere during late spring 1997 and 2000 were performed with the Chemical Lagrangian Model of the Stratosphere (CLaMS. The simulations were performed for the entire northern hemisphere on two isentropic levels 450 K (~18 km and 585 K (~24 km. The spatial distribution and the lifetime of the vortex remnants formed after the vortex breakup in May 1997 display different behavior above and below 20 km. Above 20 km, vortex remnants propagate southward (up to 40°N and are "frozen in'' in the summer circulation without significant mixing. Below 20 km the southward propagation of the remnants is bounded by the subtropical jet. Their lifetime is shorter by a factor of 2 than that above 20 km, owing to significant stirring below this altitude. The behavior of vortex remnants formed in March 2000 is similar but, due to an earlier vortex breakup, dominated during the first 6 weeks after the vortex breakup by westerly winds, even above 20 km. Vortex remnants formed in May 1997 are characterized by large mixing ratios of HCl indicating negligible, halogen-induced ozone loss. In contrast, mid-latitude ozone loss in late boreal spring 2000 is dominated, until mid-April, by halogen-induced ozone destruction within the vortex remnants, and subsequent transport of the ozone-depleted polar air masses (dilution into the mid-latitudes. By varying the intensity of mixing in CLaMS, the impact of mixing on the formation of ClONO2 and ozone depletion is investigated. We find that the photochemical decomposition of HNO3 and not mixing with NOx-rich mid-latitude air is the main source of NOx within the vortex remnants in March and April 2000. Ozone depletion in the remnants is driven by ClOx photolytically formed from ClONO2. At the end of May 1997, the halogen-induced ozone deficit at 450 K poleward of 30°N amounts to ~12% with ~10% in the polar vortex and ~2% in well-isolated vortex remnants

  17. Combined effects of carbonate alkalinity and pH on survival, growth and haemocyte parameters of the Venus clam Cyclina sinensis.

    Science.gov (United States)

    Lin, Tingting; Lai, Qifang; Yao, Zongli; Lu, Jianxue; Zhou, Kai; Wang, Hui

    2013-08-01

    Carbonate alkalinity (CA) and pH are considered to be two important stress factors that determine the response of aquatic animals to sudden transfers into saline-alkaline water. To evaluate the potential for aquaculture production of Venus clams (Cyclina sinensis) farmed in saline-alkaline water, the combined effects of CA (2.5 (control), 10.0, 20.0 and 40.0 meq/l) and pH (8.0 (control), 8.5, 9.0 and 9.5) on survival rate was monitored every day for 10 days. Length gain rate (LGR) and weight gain rate (WGR) were also monitored for two months, and total haemocyte count (THC), phagocytic rate (PR) and haemocyte mortality (HM) were measured for 3, 6, 12 and 24 days under the same water temperature (20 °C) and salinity (15‰) conditions. The results showed that survival rates in treatments of CA ≤ 20.0, combined with pH ≤ 9.0, were 100%. LGR and WGR in treatments of CA 2.5 & pH 8.0 (control), CA 2.5 & pH 8.5 and CA 10.0 & pH 8.0 exhibited the largest values (P > 0.05), while in other treatments, they showed a decreasing trend with an increase in either CA or pH or both (P 0.05), however, in other treatments, they presented significant differences, especially on day 3 and 6 (P pH, but returned to control levels on day 12. In conclusion, in this study, a strong interaction between CA and pH was observed. Additionally, it was ascertained that the Venus clam C. sinensis can withstand the stress of CA 20.0 combined pH 9.0, although individuals grows slowly and may take approximately 12 days to recover to the unstressed condition. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Fate of isotopically labeled zinc oxide nanoparticles in sediment and effects on two endobenthic species, the clam Scrobicularia plana and the ragworm Hediste diversicolor.

    Science.gov (United States)

    Buffet, Pierre-Emmanuel; Amiard-Triquet, Claude; Dybowska, Agnieszka; Risso-de Faverney, Christine; Guibbolini, Marielle; Valsami-Jones, Eugénia; Mouneyrac, Catherine

    2012-10-01

    Although it is reported that metal and metal oxide nanoparticles, which are among the most rapidly commercialized materials, can cause toxicity to organisms, their fate in the environment and toxicity to marine organisms are not well understood. In this study, we used a stable isotope labelling approach to trace the fate of nanoparticles (NPs) in sediments and also investigated bio-uptake in two estuarine intra-sedimentary invertebrates Scrobicularia plana and Nereis diversicolor. We selected exposure to 3 mg kg(-1) sediment ZnO NPs since this level is a realistic prediction of the environmental concentration in sediments. 67ZnO NPs (DLS: 21-34 nm, positively charged: 31.3 mV) suspensions were synthesised in diethylene glycol (DEG). We explored the fate of 67ZnO NPs in sediment, 67Zn bioaccumulation and the biochemical (biomarkers of defence and damage) and behavioural (burrowing kinetics and feeding rates) biomarkers in both species to 67ZnO NPs and DEG on its own during a 16 d laboratory exposure. After exposure, 67Zn concentrations in sediment showed higher levels in the upper section (1cm: 2.59 mg kg(-1)) decreasing progressively (2 cm: 1.63 mg kg(-1), 3 cm: 0.90 mg kg(-1), 4 cm: 0.67 mg kg(-1)) to a minimum value at the bottom (5 cm: 0.31 mg kg(-1)). 67Zn bioaccumulation was observed in both organisms exposed to 67ZnO NPs in DEG but no major inter-species differences were found. At the biochemical level, 67ZnO NPs exposure significantly induced increased glutathione-S-transferase activity in worms and catalase activity in clams whereas superoxide dismutase activity and thiobarbituric acid reactive substance levels were not affected in any species. Exposure to DEG on its own leads to a significant increase of metallothionein-like protein levels in clams compared with those exposed to 67ZnO NPs or controls. Burrowing behaviour as well as feeding rate were significantly impaired in both species exposed to 67ZnO NPs. Concerning exposure to DEG on its own

  19. Prevention: Exercise

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    Full Text Available ... Exercise Strength Training for the Elderly Other Back Pack Safety Pregnancy and Back Pain Preventing Osteoporosis Back ... in very slightly. Hold a ball directly in front of you. Keep your abdominal muscles tight and ...

  20. Prevention: Exercise

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    Full Text Available ... Tips for a Healthy Back Smoking Weight Patient Safety Exercise Strengthening Strengthen Your Core! Stretching/Flexibility Aerobic ... Strength Training for the Elderly Other Back Pack Safety Pregnancy and Back Pain Preventing Osteoporosis Back Pain ...

  1. Prevent Shingles

    Science.gov (United States)

    ... Submit What's this? Submit Button Past Emails Prevent Shingles Language: English (US) Español (Spanish) Recommend on Facebook ... that can result in vision loss. Older Adults & Shingles As you get older, you are more likely ...

  2. Prevention: Exercise

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    Full Text Available ... Epidural Steroid Injections Lumbar Zygapophysical (Facet) Joint Injections PREVENTION Lifestyle Choices 10 Tips for a Healthy Back Smoking Weight Patient Safety Exercise Strengthening Strengthen Your Core! ...

  3. Prevention: Exercise

    Medline Plus

    Full Text Available ... and Education Injection Treatments for Spinal Pain Epidural Steroid Injections Lumbar Zygapophysical (Facet) Joint Injections PREVENTION Lifestyle ... Z Spine Specialists Videos 9 for Spine Epidural Steroid Injections Exercise: The Backbone of Spine Treatment Spondylolisthesis ...

  4. Prevention: Exercise

    Medline Plus

    Full Text Available ... A SPECIALIST Prevention Strengthening Exercise Committee Exercise Committee Core Strengthening Many popular forms of exercise focus on ... acute pain, you should stop doing it. Transverse Core Strengthening This strengthens the muscles that cross from ...

  5. Prevention: Exercise

    Medline Plus

    Full Text Available ... Lumbar Zygapophysical (Facet) Joint Injections PREVENTION Lifestyle Choices 10 Tips for a Healthy Back Smoking Weight Patient ... the floor; rotate from side to side. Repeat 10 times. Check with your physician; if you are ...

  6. Prevention: Exercise

    Medline Plus

    Full Text Available ... Pregnancy and Back Pain Preventing Osteoporosis Back Pain Basics Book RESOURCES Patient ... popular forms of exercise focus on core strengthening, or building the muscles that provide support for your body. Pilates, yoga and martial arts ...

  7. HIV Prevention

    Centers for Disease Control (CDC) Podcasts

    2012-02-01

    Dr. Kevin Fenton, Director of CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, talks about steps people can take to protect their health from HIV.  Created: 2/1/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 2/1/2012.

  8. Seasonal variations of Escherichia coli contamination in clams (Chamelea gallina harvested in the Adriatic Sea (San Benedetto del Tronto district, Italy

    Directory of Open Access Journals (Sweden)

    Cesare Ciccarelli

    2014-06-01

    Full Text Available In the European Union, the classification of shellfish harvesting areas depends on levels of Escherichia coli checked in shellfish flesh and determines whether post-harvest treatment required before shellfish can be sold for human consumption. Nevertheless, intermittent sources of contamination, such as rainfall and runoff from agricultural and urban lands, may give rise to seasonal variations of E. coli concentration, hence an annual classification could not be correct. In this study, we investigated the microbial trend in clams (Chamelea gallina harvested from the district of San Benedetto del Tronto, Italy. The Algaeadria database, a monitoring network for the whole Adriatic area, provided results from 2005 to 2012. E. coli values compliant and non-compliant with food safety criteria were evaluated by graphical data analysis tools and one-tailed Fisher’s exact test. The results showed a clear general seasonal trend and, in one of the considered areas, the non-compliant values from July to February were significantly lower than those from March to June (P<0.05. These findings may scientifically support a seasonal classification.

  9. Population subdivision of the surf clam Mactra chinensis in the East China Sea: Changjiang River outflow is not the sole driver.

    Science.gov (United States)

    Ni, Gang; Li, Qi; Ni, Lehai; Kong, Lingfeng; Yu, Hong

    2015-01-01

    The northwestern Pacific, characterized by unique tectonic and hydrological settings, has greatly intrigued marine phylogeographers. However, current studies mostly focus on the influence of Pleistocene isolation of sea basins in population structure of species in the region, leaving the contribution of other factors (such as freshwater outflow and environmental gradients) largely unexploited. Here we shed light on the question by investigating phylogeography of the surf clam Mactra chinensis in the East China Sea (ECS). Genetic information was acquired from 501 specimens collected from its main distribution in the region, represented by mitochondrial cytochrome oxidase I (COI) and nine polymorphic microsatellite loci. A shallow and star-like phylogeny was revealed for all COI haplotypes, indicating the origin of populations from a single refugium. Although no divergent lineages existed, population subdivision was detected in both data sets. The most striking pattern was the significant differentiation between populations north and south of a biogeographic boundary-the Changjiang Estuary, suggesting a barrier effect of the freshwater outflow to gene flow. For the northern group, substructure was revealed by COI result as one southernmost population was significant different from other ones. Clear latitude gradations in allele frequencies were revealed by microsatellite analyses, likely influenced by environmental gradient factors such as temperature. Our results demonstrate that genetic subdivision can arise for populations within the ECS despite they have a single origin, and multiple mechanisms including Changjiang River outflow, environmental gradient factors and life-history traits may act in combination in the process.

  10. Population subdivision of the surf clam Mactra chinensis in the East China Sea: Changjiang River outflow is not the sole driver

    Directory of Open Access Journals (Sweden)

    Gang Ni

    2015-09-01

    Full Text Available The northwestern Pacific, characterized by unique tectonic and hydrological settings, has greatly intrigued marine phylogeographers. However, current studies mostly focus on the influence of Pleistocene isolation of sea basins in population structure of species in the region, leaving the contribution of other factors (such as freshwater outflow and environmental gradients largely unexploited. Here we shed light on the question by investigating phylogeography of the surf clam Mactra chinensis in the East China Sea (ECS. Genetic information was acquired from 501 specimens collected from its main distribution in the region, represented by mitochondrial cytochrome oxidase I (COI and nine polymorphic microsatellite loci. A shallow and star-like phylogeny was revealed for all COI haplotypes, indicating the origin of populations from a single refugium. Although no divergent lineages existed, population subdivision was detected in both data sets. The most striking pattern was the significant differentiation between populations north and south of a biogeographic boundary—the Changjiang Estuary, suggesting a barrier effect of the freshwater outflow to gene flow. For the northern group, substructure was revealed by COI result as one southernmost population was significant different from other ones. Clear latitude gradations in allele frequencies were revealed by microsatellite analyses, likely influenced by environmental gradient factors such as temperature. Our results demonstrate that genetic subdivision can arise for populations within the ECS despite they have a single origin, and multiple mechanisms including Changjiang River outflow, environmental gradient factors and life-history traits may act in combination in the process.

  11. Interannual to decadal variability of summer sea surface temperature in the Sea of Okhotsk recorded in the shell growth history of Stimpson's hard clams (Mercenaria stimpsoni)

    Science.gov (United States)

    Tanabe, Kazushige; Mimura, Toshihiro; Miyaji, Tsuzumi; Shirai, Kotaro; Kubota, Kaoru; Murakami-Sugihara, Naoko; Schöne, Bernd R.

    2017-10-01

    Sclerochronological and shell stable oxygen isotopic analyses were conducted on live-caught specimens of Stimpson's hard clams, Mercenaria stimpsoni, from the southern Sea of Okhotsk, off northern Hokkaido, Japan. In this region, the main growing season of this species during early ontogeny (below the age of 12 years) lasts from mid-spring to mid-fall at sea surface temperatures (SST) between approximately 10 and 22 °C. Growth cessation begins between late fall and early spring at SST, below approximately 6 °C; however, shell growth was largely limited to the summer season later in life. Counting of annual increments indicated that this species had a relatively long life span of up to 100 years. Annual shell growth rates were high during early ontogeny and declined abruptly afterwards. Mean standardized shell growth indices (SGIs) of long-lived specimens were positively correlated to the mean summer SSTs near the sampling site and in the coastal waters off northern Hokkaido. The SGI chronology of the longest-lived specimen (99 years old) exhibited periodicities of approximately 10 and 5 years during the calendar years 1920-2011, possibly reflecting the quasi-decadal variability of summer SST in the southern Sea of Okhotsk. These findings indicate that M. stimpsoni could serve as an archive to reconstruct past marine climate changes in the Sea of Okhotsk.

  12. Comparing the Survival Rate of Mangrove Clam, Polymesoda (Geloina) spp. (Solander 1876) Through Field Experiments in Mangrove Forests of Iriomote Island.

    Science.gov (United States)

    Washitani, Yasuko; Hayakawa, Reiko; Li, Meihua; Shibata, Shozo

    2017-06-01

    Polymesoda spp., which represent bivalves in the mangrove ecosystem, inhabit the mangrove forests of the Indo-Pacific region. They tend not to be broadly distributed across zones within the mangrove forest, but are instead typically encountered in the mesozone. We conducted field rearing experiments on four plots which were set across a mangrove forest along the Urauchi River of Iriomote Island, from the seaward to landward sides, over a period of 10 months. We compared the survival rates of clams at these plots with different environment for four months. Salinity was also measured during the study period, and we established a correlation between survival rate and change in salinity of each plot. The survival rate of the plot in the mesozone was 90%, that of two plots which were positioned in the seaward zone of the mesozone was 40%, and that of the plot on the landward side was 0%. In plot 4, the ambient water of the bivalves was fresh water. The salinity of the seaward zone changed rapidly in one day, or the salinity of the ambient water surrounding the bivalves was high for a long period of time. In Plot 3, salinity change was gradual, and the average salinity was lower than in Plots 1 and 2. This study indicates that salinity level affects bivalve survival rate and that area similar the mesozone, where gradual salinity change and average salinity were neither too high nor too low, are suitable for these species.

  13. Evidence for the role of horizontal transfer in generating pVT1, a large mosaic conjugative plasmid from the clam pathogen, Vibrio tapetis.

    Directory of Open Access Journals (Sweden)

    Gaël Erauso

    Full Text Available The marine bacterium Vibrio tapetis is the causative agent of the brown ring disease, which affects the clam Ruditapes philippinarum and causes heavy economic losses in North of Europe and in Eastern Asia. Further characterization of V. tapetis isolates showed that all the investigated strains harbored at least one large plasmid. We determined the sequence of the 82,266 bp plasmid pVT1 from the CECT4600(T reference strain and analyzed its genetic content. pVT1 is a mosaic plasmid closely related to several conjugative plasmids isolated from Vibrio vulnificus strains and was shown to be itself conjugative in Vibrios. In addition, it contains DNA regions that have similarity with several other plasmids from marine bacteria (Vibrio sp., Shewanella sp., Listonella anguillarum and Photobacterium profundum. pVT1 contains a number of mobile elements, including twelve Insertion Sequences or inactivated IS genes and an RS1 phage element related to the CTXphi phage of V. cholerae. The genetic organization of pVT1 underscores an important role of horizontal gene transfer through conjugative plasmid shuffling and transposition events in the acquisition of new genetic resources and in generating the pVT1 modular organization. In addition, pVT1 presents a copy number of 9, relatively high for a conjugative plasmid, and appears to belong to a new type of replicon, which may be specific to Vibrionaceae and Shewanelleacae.

  14. The assessment of environmental pollution along the coast of Beibu Gulf, northern South China Sea: an integrated biomarker approach in the clam Meretrix meretrix.

    Science.gov (United States)

    Meng, Fanping; Wang, Zhifeng; Cheng, Fenglian; Du, Xiuping; Fu, Wenchao; Wang, Qun; Yi, Xiaoyan; Li, Yongfu; Zhou, You

    2013-04-01

    The clam Meretrix meretrix was used as a biomonitor to implement an environmental monitoring program along the coast of Beibu Gulf in October 2011. This program not only analyzed biomarkers including acetylcholinesterase, glutathione peroxidase, glutathione S-transferase, catalase and superoxide dismutase activities, total glutathione content and lipid peroxidation level in M. meretrix but also adopted a multi-biomarker approach - integrated biomarker response (IBR) to assess the environmental quality in this ecosystem. In addition, the metal (Hg, As, Cu, Pb, Zn, Cd and Cr) and polychlorinated biphenyls (PCBs) content in the surface sediment at the study area were also measured. The results showed that IBR index was able to distinguish a space trend between sampling sites with different degrees of anthropogenic environmental stress. Integrated contamination degree were displayed in the form of star plots and compared to IBR plots. There was a visual consistency between the pollution level and IBR variation. Based on the results, it was proved that the IBR method coupled with chemical analysis was quite useful for the assessment of environmental pollution in the coastal system. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Ocean acidification weakens the immune response of blood clam through hampering the NF-kappa β and toll-like receptor pathways.

    Science.gov (United States)

    Liu, Saixi; Shi, Wei; Guo, Cheng; Zhao, Xinguo; Han, Yu; Peng, Chao; Chai, Xueliang; Liu, Guangxu

    2016-07-01

    The impact of pCO2 driven ocean acidification on marine bivalve immunity remains poorly understood. To date, this impact has only been investigated in a few bivalve species and the underlying molecular mechanism remains unknown. In the present study, the effects of the realistic future ocean pCO2 levels (pH at 8.1, 7.8, and 7.4) on the total number of haemocyte cells (THC), phagocytosis status, blood cell types composition, and expression levels of twelve genes from the NF-kappa β signaling and toll-like receptor pathways of a typical bottom burrowing bivalve, blood clam (Tegillarca granosa), were investigated. The results obtained showed that while both THC number and phagocytosis frequency were significantly reduced, the percentage of red and basophil granulocytes were significantly decreased and increased, respectively, upon exposure to elevated pCO2. In addition, exposure to pCO2 acidified seawater generally led to a significant down-regulation in the inducer and key response genes of NF-kappa β signaling and toll-like receptor pathways. The results of the present study revealed that ocean acidification may hamper immune responses of the bivalve T. granosa which subsequently render individuals more susceptible to pathogens attacks such as those from virus and bacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. The Asian clam Corbicula fluminea as a biomonitor of trace element contamination: accounting for different sources of variation using an hierarchical linear model.

    Science.gov (United States)

    Shoults-Wilson, W Aaron; Peterson, James T; Unrine, Jason M; Rickard, James; Black, Marsha C

    2009-10-01

    In the present study, specimens of the invasive clam, Corbicula fluminea, were collected above and below possible sources of potentially toxic trace elements (As, Cd, Cr, Cu, Hg, Pb, and Zn) in the Altamaha River system (Georgia, U.S.A.). Bioaccumulation of these elements was quantified, along with environmental (water and sediment) concentrations. Hierarchical linear models were used to account for variability in tissue concentrations related to environmental (site water chemistry and sediment characteristics) and individual (growth metrics) variables while identifying the strongest relations between these variables and trace element accumulation. The present study found significantly elevated concentrations of Cd, Cu, and Hg downstream of the outfall of kaolin-processing facilities, Zn downstream of a tire cording facility, and Cr downstream of both a nuclear power plant and a paper pulp mill. Models of the present study indicated that variation in trace element accumulation was linked to distance upstream from the estuary, dissolved oxygen, percentage of silt and clay in the sediment, elemental concentrations in sediment, shell length, and bivalve condition index. By explicitly modeling environmental variability, the Hierarchical linear modeling procedure allowed the identification of sites showing increased accumulation of trace elements that may have been caused by human activity. Hierarchical linear modeling is a useful tool for accounting for environmental and individual sources of variation in bioaccumulation studies.

  17. First occurrence of the exotic Asian clam Corbicula fluminea (Muller, 1774 in the Jundiaí-Mirim River Basin, SP, Brazil

    Directory of Open Access Journals (Sweden)

    Frederico Guilherme de Souza Beghelli

    2014-07-01

    Full Text Available Corbicula fluminea is a naturally occurring Asian bivalve that was spread around the world, and which has become a highly aggressive invasive species in many countries. C. fluminea has many ecological, economic and social impacts, such as the extinction of native species, ecosystems alterations, and damage to pipes and hydropower turbines. As an illustration of the potential damage that proliferation of C. fluminea can cause, it is noted that the United States government spends more than 1 billion dollars per year to control this species. This work recorded the first occurrence of the Asian clam C. fluminea in the Jundiaí- Mirim Basin, SP, Brazil, and included basic ecological information such as density, frequency distribution of size and species distribution along the basin. Seventy-eight individuals were sampled with a van Veen grab along the basin. The specimens were identified and measured. The exotic species was found only in two of four sampling points and its distribution was possibly influenced by sediment composition and water flow. Moderate densities were calculated, ranging from 12 to 235 ind.m-2 . Our data suggest that young populations are growing in the basin. The presence of C. fluminea is a concern for the maintenance of the ecosystem and for different water uses in the Jundiai region.

  18. Cd, Cu, Pb and Zn in clams and sediments from an impacted estuary by the oil industry in the southwestern Gulf of Mexico: concentrations and bioaccumulation factors.

    Science.gov (United States)

    Ruelas-Inzunza, J; Spanopoulos-Zarco, P; Páez-Osuna, F

    2009-12-01

    With the objective of estimating the temporal variation and bioavailability of Cd, Cu, Pb and Zn in Coatzacoalcos estuary, the biota-sediment accumulation factors (BSAF) were calculated. For this purpose, surficial sediments and clams from 14 selected sites were collected during three climatic seasons. In surficial sediments, highest levels of Cd and Cu were measured during the rainy season near to the industrial area of Minatitlan, while highest concentrations of Pb and Zn were registered during the windy season in sediments collected near to the industrial area of Coatzacoalcos. Considering all the sampling seasons and bivalve species, average metal concentrations followed the order Zn > Cu > Cd > Pb. BSAF ranged from 0.01 (Pb) in Corbicula fluminea during the hot season to 25.1 (Cd) in Polymesoda caroliniana during the windy season. BSAF of Cd, Cu and Zn were higher during the windy season; in the case of Pb, the dry season was the time when such figure was more elevated. It can be stated that Polymesoda caroliniana is a net accumulator of Cd and Zn and a weak accumulator of Pb for the studied estuary.

  19. Application of electron-beam irradiation on the production of salted and seasoned short-necked clam, Tapes Pilippinarum, for safe distribution

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.; Song, H.P.; Choe, J.H.; Jung, S. [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Jang, A. [Quality Control and Utilization of Animal Products, National Institute of Animal Science, Suwon 441-706 (Korea, Republic of); Kim, Y.J. [Food Safety Research Division, Korea Food Research Institute, Seongnam 463-746 (Korea, Republic of); Jo, C. [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)], E-mail: cheorun@cnu.ac.kr

    2009-07-15

    Salted and seasoned short-necked clam (Tapes Philippinarum; SNC) and its major ingredients, red hot pepper powder, ginger, garlic and onion were irradiated at 0.5, 1, 2 and 5 kGy, respectively, and the microbiological and sensory quality were evaluated. The water activities of SNC and red pepper powder were 0.91 and 0.56, respectively, and others were higher than 0.97. The initial microbial populations of SNC were approximately 3.99, 4.38 and 2.22 log CFU/g for total aerobic bacteria, yeast and mold, and coliform bacteria. The highest contamination of total aerobic bacteria was detected from ground ginger among ingredients at 5.51 log CFU/g. Electron-beam irradiation (0, 0.5, 1, 2 and 5 kGy) significantly reduced the initial microbial level of SNC and its ingredients not only immediately after irradiation, but also during storage at 10 {sup o}C for 4 weeks (p<0.05). There was no adverse change of sensory score except for the color of onion irradiated at 5 kGy, which results in a lower score than control. From the results electron-beam irradiation is a useful tool to enhance the storage stability and safe distribution of SNC.

  20. Effect of feedback techniques for lower back pain on gluteus maximus and oblique abdominal muscle activity and angle of pelvic rotation during the clam exercise.

    Science.gov (United States)

    Koh, Eun-Kyung; Park, Kyue-Nam; Jung, Do-Young

    2016-11-01

    This study was conducted in order to determine the effect of feedback tools on activities of the gluteus maximus (Gmax) and oblique abdominal muscles and the angle of pelvic rotation during clam exercise (CE). Comparative study using repeated measures. University laboratory. Sixteen subjects with lower back pain. Each subject performed the CE without feedback, the CE using a pressure biofeedback unit (CE-PBU), and the CE with palpation and visual feedback (CE-PVF). Electromyographic (EMG) activity and the angles of pelvic rotation were measured using surface EMG and a three-dimensional motion-analysis system, respectively. One-way repeated-measures ANOVA followed by the Bonferroni post hoc test were used to compare the EMG activity in each muscle as well as the angle of pelvic rotation during the CE, CE-PBU, and CE-PVF. The results of post-hoc testing showed a significantly reduced angle of pelvic rotation and significantly more Gmax EMG activity during the CE-PVF compared with during the CE and CE-PBU. These findings suggest that palpation and visual feedback is effective for activating the Gmax and controlling pelvic rotation during the CE in subjects with lower back pain. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. The usability of ark clam shell (Anadara granosa) as calcium precursor to produce hydroxyapatite nanoparticle via wet chemical precipitate method in various sintering temperature.

    Science.gov (United States)

    Khiri, Mohammad Zulhasif Ahmad; Matori, Khamirul Amin; Zainuddin, Norhazlin; Abdullah, Che Azurahanim Che; Alassan, Zarifah Nadakkavil; Baharuddin, Nur Fadilah; Zaid, Mohd Hafiz Mohd

    2016-01-01

    This paper reported the uses of ark clam shell calcium precursor in order to form hydroxyapatite (HA) via the wet chemical precipitation method. The main objective of this research is to acquire better understanding regarding the effect of sintering temperature in the fabrication of HA. Throughout experiment, the ratio of Ca:P were constantly controlled, between 1.67 and 2.00. The formation of HA at these ratio was confirmed by means of energy-dispersive X-ray spectroscopy analysis. In addition, the effect of sintering temperature on the formation of HA was observed using X-ray diffraction analysis, while the structural and morphology was determined by means of field emission scanning electron microscopy. The formation of HA nanoparticle was recorded (~35-69 nm) in the form of as-synthesize HA powder. The bonding compound appeared in the formation of HA was carried out using Fourier transform infrared spectroscopy such as biomaterials that are expected to find potential applications in orthopedic and biomedical industries .

  2. A novel paramyxean parasite, Marteilia octospora n. sp. (Cercozoa) infecting the Grooved Razor Shell clam Solen marginatus from Galicia (NW Spain).

    Science.gov (United States)

    Ruiz, Maite; López, Carmen; Lee, Ren-Shiang; Rodríguez, Rosana; Darriba, Susana

    2016-03-01

    Protozoan parasites of the genus Marteilia have been detected in marine bivalves and other invertebrates around the world, associated in some cases with mass mortalities. The present paper reports the characterization of the Marteilia sp. protozoan infecting the digestive gland of the Grooved Razor Shell clam (Solen marginatus) from Galicia (NW Spain), proposing a novel species in the genus: Marteilia octospora n. sp. Morphological and molecular techniques were used for the description of this parasite. Tissue imprints were essential in the study to confirm the presence of 8 spores per sporangium, a number never reported in other species from this genus. An ultrastructural study revealed that the size and number of dense granules, free in the mature sporangia, were quite different from granules in other Marteilia spp. Another morphological difference is the absence of a layer of concentric membranes found surrounding the mature spore in other species. In addition, concentric membranous structures observed in the different stages of the parasite have never been mentioned in other species of genus Marteilia. Moreover, molecular analysis of the rDNA intergenic spacer (IGS) and the internal transcribed spacer (ITS-1) showed differences with the sequences available for other Marteilia spp. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Recovery of macroinvertebrates by screening in the field: a comparison between coarse (1.18 mm) and fine (0.60 mm) mesh sieves

    Science.gov (United States)

    Dukerschein, J.T.; Gent, R.; Sauer, J.

    1996-01-01

    We evaluated the potential loss of target benthic macroinvertebrates from coarse-mesh field wash down of samples through a 1.18-mm mesh sieve nested on a 0.60-mm mesh sieve. Visible target organisms (midges, mayflies, and fingernail clams) in the 1.18-mm mesh sieve were removed from the sample and enumerated in the field. The entire contents of both sieves were preserved for subsequent laboratory enumeration under 4X magnification. Percent recoveries from each treatment were based on total intact organisms found in all sieves. Percent recovery for fingernail clams found in the field (31%) was lower than for mayflies (79%) and midges (88%). Laboratory enumeration of organisms retained by the 1.18-mm sieve yielded additional fingernail clams (to total 74% recovered in the field and lab), mayflies (to total 89%), and midges (to total 91%). If the 1.18-mm sieve is used alone in the field, it is adequate to monitor mayflies, midges >1 cm, and adult fingernail clams greater than or equal to 5.0 mm shell length.

  4. Bullying Prevention

    Science.gov (United States)

    Kemp, Patrice

    2016-01-01

    The focus of the milestone project is to focus on bridging the gap of bullying and classroom instruction methods. There has to be a defined expectations and level of accountability that has to be defined when supporting and implementing a plan linked to bullying prevention. All individuals involved in the student's learning have to be aware of…

  5. Prevention: Exercise

    Medline Plus

    Full Text Available ... Strengthen Your Core! Stretching/Flexibility Aerobic Exercise Cervical Exercise Strength Training for the Elderly Other Back Pack Safety Pregnancy and Back Pain Preventing Osteoporosis Back Pain Basics Book RESOURCES ... The Backbone of Spine Treatment Spondylolisthesis BLOG FIND ...

  6. Prevent Pneumonia

    Centers for Disease Control (CDC) Podcasts

    2015-08-06

    CDC’s Matthew Westercamp explains what pneumonia is, its symptoms, and how to prevent it.  Created: 8/6/2015 by National Center for Immunization and Respiratory Diseases (NCIRD), Division of Bacterial Diseases (DBD), Respiratory Diseases Branch (RDB).   Date Released: 8/6/2015.

  7. HIV Prevention

    Science.gov (United States)

    ... Abroad Treatment Basic Statistics Get Tested Find an HIV testing site near you. Enter ZIP code or city Follow HIV/AIDS CDC HIV CDC HIV/AIDS See RSS | ... Collapse All Is abstinence the only 100% effective HIV prevention option? Yes. Abstinence means not having oral, ...

  8. Prevention: Exercise

    Medline Plus

    Full Text Available ... Information Feature Articles Patient Q&A Success Stories Definitions Anatomy of the Spine Definitions A-Z Spine Specialists Videos 9 for Spine Epidural Steroid Injections Exercise: The Backbone of Spine Treatment Spondylolisthesis BLOG FIND A SPECIALIST Prevention ...

  9. Molecular characterization of two kazal-type serine proteinase inhibitor genes in the surf clam Mesodesma donacium exposed to Vibrio anguillarum.

    Science.gov (United States)

    Maldonado-Aguayo, Waleska; Núñez-Acuña, Gustavo; Valenzuela-Muñoz, Valentina; Chávez-Mardones, Jacqueline; Gallardo-Escárate, Cristian

    2013-06-01

    This study reports two kazal-type serine protease inhibitors (KPI) identified in a cDNA library from the surf clam Mesodesma donacium, and characterized through Rapid Amplification of cDNA Ends (RACE). The KPIs, denoted as MdSPI-1 and MdSPI-2, presented full sequences of 1139 bp and 781 bp respectively. MdSPI-1 had a 5'untranslated region (UTR) of 175 bp, a 3'UTR of 283 bp and an open reading frame (ORF) of 681 pb that encodes for 227 amino acids. MdSPI-2 showed a 5'UTR of 70 bp, a 3'UTR of 279 bp and an ORF of 432 bp that encodes for 144 amino acids. Both sequences presented two kazal-type tandem domains. Phylogenetic analysis of MdSPI-1 and MdSPI-2 shows a main clade composed by other bivalve species and closely related crustaceans. Real time PCR analysis showed that MdSPI-1 is mainly up-regulated in mantle, foot, gills and muscle tissues, while MdSPI-2 is expressed principally in foot tissue. Moreover, to evaluate the immune response of MdSPI-1 and MdSPI-2, infections with Vibrio anguillarum were performed. Herein, MdSPI-1 and MdSPI-2 transcription expression were significantly up-regulated at 2 and 8 h post-challenge. Our results suggest that MdSPI-1 and MdSPI-2 are important humoral factors of innate immunity in M. donacium. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. A Microarray Study of Carpet-Shell Clam (Ruditapes decussatus Shows Common and Organ-Specific Growth-Related Gene Expression Differences in Gills and Digestive Gland

    Directory of Open Access Journals (Sweden)

    Carlos Saavedra

    2017-11-01

    Full Text Available Growth rate is one of the most important traits from the point of view of individual fitness and commercial production in mollusks, but its molecular and physiological basis is poorly known. We have studied differential gene expression related to differences in growth rate in adult individuals of the commercial marine clam Ruditapes decussatus. Gene expression in the gills and the digestive gland was analyzed in 5 fast-growing and five slow-growing animals by means of an oligonucleotide microarray containing 14,003 probes. A total of 356 differentially expressed genes (DEG were found. We tested the hypothesis that differential expression might be concentrated at the growth control gene core (GCGC, i.e., the set of genes that underlie the molecular mechanisms of genetic control of tissue and organ growth and body size, as demonstrated in model organisms. The GCGC includes the genes coding for enzymes of the insulin/insulin-like growth factor signaling pathway (IIS, enzymes of four additional signaling pathways (Raf/Ras/Mapk, Jnk, TOR, and Hippo, and transcription factors acting at the end of those pathways. Only two out of 97 GCGC genes present in the microarray showed differential expression, indicating a very little contribution of GCGC genes to growth-related differential gene expression. Forty eight DEGs were shared by both organs, with gene ontology (GO annotations corresponding to transcription regulation, RNA splicing, sugar metabolism, protein catabolism, immunity, defense against pathogens, and fatty acid biosynthesis. GO term enrichment tests indicated that genes related to growth regulation, development and morphogenesis, extracellular matrix proteins, and proteolysis were overrepresented in the gills. In the digestive gland overrepresented GO terms referred to gene expression control through chromatin rearrangement, RAS-related small GTPases, glucolysis, and energy metabolism. These analyses suggest a relevant role of, among others

  11. Effect of permethrin, anthracene and mixture exposure on shell components, enzymatic activities and proteins status in the Mediterranean clam Venerupis decussata

    Energy Technology Data Exchange (ETDEWEB)

    Sellami, Badreddine, E-mail: sellamibadreddine@gmail.com [Laboratory of Environment Biomonitoring, Coastal Ecology Unit, Faculty of Sciences of Bizerta, University of Carthage, 7021 Zarzouna (Tunisia); Khazri, Abdelhafidh [Laboratory of Environment Biomonitoring, Coastal Ecology Unit, Faculty of Sciences of Bizerta, University of Carthage, 7021 Zarzouna (Tunisia); Mezni, Amine [Unit of Research 99/UR12-30, Department of Chemistry, Faculty of Sciences of Bizerte, 7021 Jarzouna (Tunisia); Louati, Héla; Dellali, Mohamed; Aissa, Patricia; Mahmoudi, Ezzeddine; Beyrem, Hamouda [Laboratory of Environment Biomonitoring, Coastal Ecology Unit, Faculty of Sciences of Bizerta, University of Carthage, 7021 Zarzouna (Tunisia); Sheehan, David, E-mail: d.sheehan@ucc.ie [Environmental Research Institute and Department of Biochemistry, University College Cork, Western Gateway Building, Western Road, Cork (Ireland)

    2015-01-15

    Highlights: • We assessed toxicity of anthracene, permethrin and their mixture on clams. • Tissue and stressor-dependent changes were observed in biochemical responses. • Permethrin induces phase transition from aragonite to calcite in shell structure. • Interactive effects were observed on digestive gland and gill biomarkers. • Both approaches give new vision to risk assessment of organic pollution. - Abstract: Anthracene (ANT) and permethrin (PER) are two of the more toxic compounds reaching the marine environment. This study aimed to determine the impact of these molecules on Venerupis decussata, an economically important species cultured on the Tunisian coast. Shell structure and its possible transformation upon exposure to the two contaminants were studied by X-ray diffraction and gravimetric analyses. Results revealed a phase transition in shell composition from aragonite to calcite after PER exposure, to a mixture of PER and ANT (Mix) but not for ANT alone. Catalase (CAT), superoxide dismutase (SOD) and glutathione transferase (GST) activities were determined in digestive gland and gills after exposure to ANT, PER and Mix to assess the impact of the contamination on the oxidative status of V. decussata. Enzyme activities increased in the digestive gland after PER treatment and in the gills after ANT treatment. PER exposure significantly reduced the levels of free thiols and increased levels of carbonylated proteins in the digestive gland, as compared to controls. In contrast, ANT exposure significantly reduced free thiols and increased the number of carbonylated proteins in the gills. Mix induced additive effects as measured by both enzymatic and proteomic approaches. The present study suggests that PER has a strong effect on shell structure; that PER and ANT exposure generate compound-dependent oxidative stress in the tissues of V. decussata and that a mixture of the two compounds has synergistic effects on biochemical response.

  12. Effect of permethrin, anthracene and mixture exposure on shell components, enzymatic activities and proteins status in the Mediterranean clam Venerupis decussata

    International Nuclear Information System (INIS)

    Sellami, Badreddine; Khazri, Abdelhafidh; Mezni, Amine; Louati, Héla; Dellali, Mohamed; Aissa, Patricia; Mahmoudi, Ezzeddine; Beyrem, Hamouda; Sheehan, David

    2015-01-01

    Highlights: • We assessed toxicity of anthracene, permethrin and their mixture on clams. • Tissue and stressor-dependent changes were observed in biochemical responses. • Permethrin induces phase transition from aragonite to calcite in shell structure. • Interactive effects were observed on digestive gland and gill biomarkers. • Both approaches give new vision to risk assessment of organic pollution. - Abstract: Anthracene (ANT) and permethrin (PER) are two of the more toxic compounds reaching the marine environment. This study aimed to determine the impact of these molecules on Venerupis decussata, an economically important species cultured on the Tunisian coast. Shell structure and its possible transformation upon exposure to the two contaminants were studied by X-ray diffraction and gravimetric analyses. Results revealed a phase transition in shell composition from aragonite to calcite after PER exposure, to a mixture of PER and ANT (Mix) but not for ANT alone. Catalase (CAT), superoxide dismutase (SOD) and glutathione transferase (GST) activities were determined in digestive gland and gills after exposure to ANT, PER and Mix to assess the impact of the contamination on the oxidative status of V. decussata. Enzyme activities increased in the digestive gland after PER treatment and in the gills after ANT treatment. PER exposure significantly reduced the levels of free thiols and increased levels of carbonylated proteins in the digestive gland, as compared to controls. In contrast, ANT exposure significantly reduced free thiols and increased the number of carbonylated proteins in the gills. Mix induced additive effects as measured by both enzymatic and proteomic approaches. The present study suggests that PER has a strong effect on shell structure; that PER and ANT exposure generate compound-dependent oxidative stress in the tissues of V. decussata and that a mixture of the two compounds has synergistic effects on biochemical response

  13. De Novo assembly of the Manila clam Ruditapes philippinarum transcriptome provides new insights into expression bias, mitochondrial doubly uniparental inheritance and sex determination.

    Science.gov (United States)

    Ghiselli, Fabrizio; Milani, Liliana; Chang, Peter L; Hedgecock, Dennis; Davis, Jonathan P; Nuzhdin, Sergey V; Passamonti, Marco

    2012-02-01

    Males and females share the same genome, thus, phenotypic divergence requires differential gene expression and sex-specific regulation. Accordingly, the analysis of expression patterns is pivotal to the understanding of sex determination mechanisms. Many bivalves are stable gonochoric species, but the mechanism of gonad sexualization and the genes involved are still unknown. Moreover, during the period of sexual rest, a gonad is not present and sex cannot be determined. A mechanism associated with germ line differentiation in some bivalves, including the Manila clam Ruditapes philippinarum, is the doubly uniparental inheritance (DUI) of mitochondria, a variation of strict maternal inheritance. Two mitochondrial lineages are present, one transmitted through eggs and the other through sperm, as well as a mother-dependent sex bias of the progeny. We produced a de novo annotation of 17,186 transcripts from R. philippinarum and compared the transcriptomes of males and females and identified 1,575 genes with strong sex-specific expression and 166 sex-specific single nucleotide polymorphisms, obtaining preliminary information about genes that could be involved in sex determination. Then we compared the transcriptomes between a family producing predominantly females and a family producing predominantly males to identify candidate genes involved in regulation of sex-specific aspects of DUI system, finding a relationship between sex bias and differential expression of several ubiquitination genes. In mammalian embryos, sperm mitochondria are degraded by ubiquitination. A modification of this mechanism is hypothesized to be responsible for the retention of sperm mitochondria in male embryos of DUI species. Ubiquitination can additionally regulate gene expression, playing a role in sex determination of several animals. These data enable us to develop a model that incorporates both the DUI literature and our new findings.

  14. Growth increment periodicity in the shell of the razor clam Ensis directus using stable isotopes as a method to validate age

    Directory of Open Access Journals (Sweden)

    J. F. M. F. Cardoso

    2013-07-01

    Full Text Available To evaluate the role of the razor clam Ensis directus in Dutch coastal waters, understanding its population dynamics is important. As such, the age structure of the population forms a key parameter. Accurate age determination in bivalve shells is not always straightforward due to the difficulty of interpreting externally visible growth lines. In the present paper, we aimed at validating the seasonality in growth line formation using visual techniques in combination with stable oxygen and carbon isotope analyses (δ18O and δ13C. High δ18O values in the shell coincided with growth marks on the external surface of the valve and in acetate peels of the shell's cross section. Most shell δ18O samples were assigned to the months from June to September. From November to March no samples were retrieved, indicating that the shell did not grow. The lowest reconstructed temperature (6.3 °C suggests that ~ 6 °C may be the threshold temperature for growth. Nevertheless, most of the reconstructed values fell above 14.5 °C, indicating that growth occurred mainly in the summer at relatively high temperatures. Shell δ13C profiles followed a more or less seasonal cycle, but no direct relationship could be made between δ13C values and annual growth lines. Although counting external annual growth lines led to a correct estimation of age and consequently of growth rates, we recommend analysing acetate peels of cross sections to support the distinction between annual lines and disturbance lines.

  15. Ecological effects of the harvest phase of geoduck clam (Panopea generosa Gould, 1850) aquaculture on infaunal communities in southern Puget Sound, Washington USA.

    Science.gov (United States)

    VanBlaricom, Glenn R.; Eccles, Jennifer L.; Olden, Julian D.; Mcdonald, P. Sean

    2015-01-01

    Intertidal aquaculture for geoducks (Panopea generosa Gould, 1850) is expanding in southern Puget Sound, Washington, where gently sloping sandy beaches are used for field culture. Geoduck aquaculture contributes significantly to the regional economy, but has become controversial because of a range of unresolved questions involving potential biological impacts on marine ecosystems. From 2008 through 2012, the authors used a “before-after-control-impact” experimental design, emphasizing spatial scales comparable with those used by geoduck culturists to evaluate the effects of harvesting market-ready geoducks on associated benthic infaunal communities. Infauna were sampled at three different study locations in southern Puget Sound at monthly intervals before, during, and after harvests of clams, and along extralimital transects extending away from the edges of cultured plots to assess the effects of harvest activities in adjacent uncultured habitat. Using multivariate statistical approaches, strong seasonal and spatial signals in patterns of abundance were found, but there was scant evidence of effects on the community structure associated with geoduck harvest disturbances within cultured plots. Likewise, no indications of significant “spillover” effects of harvest on uncultured habitat adjacent to cultured plots were noted. Complementary univariate approaches revealed little evidence of harvest effects on infaunal biodiversity and indications of modest effects on populations of individual infaunal taxa. Of 10 common taxa analyzed, only three showed evidence of reduced densities, although minor, after harvests whereas the remaining seven taxa indicated either neutral responses to harvest disturbances or increased abundance either during or in the months after harvest events. It is suggested that a relatively active natural disturbance regime, including both small-scale and large-scale events that occur with comparable intensity but more frequently than

  16. A novel galactosyl-binding lectin from the plasma of the blood clam, Anadara granosa (L) and a study of its combining site.

    Science.gov (United States)

    Dam, T K; Sarkar, M; Ghosal, J; Choudhury, A

    1992-11-04

    The marine blood clam species Anadara granosa (L) belong to arcidae, a family with some extraordinary haematological features. The plasma of this species exhibited strong haemagglutinating activities, from which a galactosyl binding lectin, Anadarin P, was purified in a single step affinity chromatography using Sepharose 4B-asialofetuin as an affinity matrix. The purified lectin, eluted with lactose, was found to be homogeneous by alkaline polyacrylamide disc gels, gel-filtration and isoelectric focusing. Native M(r) of the lectin was 130,000 having a PI value of 6.82 and was composed of two subunits of M(r) 17,000 and M(r) 16,000 which were noncovalently bound. The lectin was remarkably thermostable; the agglutinating titre remained unchanged over a wide range of pH (from 5 to 10) but increased with neuraminidase treated rabbit erythrocytes. Anadarin P combining site has been proposed to be small pocket-like structure which recognised only C-3 and C-4 hydroxyl groups of D-galactose. Presence of bulky groups at C-2 and C-6 exert strong steric hindrance as L-arabinose, 2-deoxy-D-galactose and D-xylose are better inhibitors than D-galactose. The lectin fails to differentiate methyl substituted galactosides as both alpha- and beta- methyl galactosides are equally active; but in case of substituted phenyl glycosides, the lectin shows different affinity towards alpha and beta anomers. The avidity of the lectin to bind the aromatic aglycons of galactosides suggests the presence of a hydrophobic region in the combining site. Interactions with some disaccharides indicate the presence of an extended area near the monosaccharide binding site.

  17. Heavy metals in sediments and soft tissues of the Antarctic clam Laternula elliptica: more evidence as a possible biomonitor of coastal marine pollution at high latitudes?

    Science.gov (United States)

    Vodopivez, Cristian; Curtosi, Antonio; Villaamil, Edda; Smichowski, Patricia; Pelletier, Emilien; Mac Cormack, Walter P

    2015-01-01

    Studies on metal contamination in 25 de Mayo Island, Antarctica, yielded controversial results. In this work, we analyzed Antarctic marine sediments and Antarctic clam (Laternula elliptica) tissues to investigate the possible use of this mollusk as a biomonitor of metals and to identify the sources of metal pollution. Different types of paint from several buildings from Carlini Station were examined to assess their contribution to the local and random metal pollution. Five sediment samples, 105 L. elliptica specimens (40.2-78.0mm length) and four types of paint were analyzed to quantify Cd, Cr, Cu, Fe, Mn, Pb and Zn using inductively coupled plasma-optical emission spectrometry. Metal concentrations in sediments were lower than the global averages of the earth's crust, with the exception of Cd and Cu. These results were related to the contribution of the local fresh-water runoff. The different varieties of paint showed low levels of Cu, Mn, Fe and Zn, whereas a broad range of values were found in the case of Cr and Pb (20-15,100 μg·g(-1) and 153-115,500 μg·g(-1) respectively). The remains of the paint would be responsible for the significant increases in Cr and Pb which are randomly detected by us and by other authors. High levels of Fe and Cd, in comparison to other Antarctic areas, appear to be related to the terrigenous materials transported by the local streams. Accumulation indexes suggested that kidney tissue from L. elliptica could be an adequate material for biomonitoring pollution with Cd, Zn and probably also Pb. In general, relationships between size and metal contents reported by other authors were not verified, suggesting that this issue should be revised. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Allergy prevention.

    Science.gov (United States)

    Muche-Borowski, Cathleen; Kopp, Matthias; Reese, Imke; Sitter, Helmut; Werfel, Thomas; Schäfer, Torsten

    2010-09-01

    The further increase of allergies in industrialized countries demands evidence-based measures of primary prevention. The recommendations as published in the guideline of 2004 were updated and consented on the basis of a systematic literature search. Evidence from the period February 2003-May 2008 was searched in the electronic databases Cochrane and MEDLINE as well as in reference lists of recent reviews and by contacting experts. The retrieved citations were screened for relevance first by title and abstract and in a second step as full paper. Levels of evidence were assigned to each included study and the methodological quality of the studies was assessed as high or low. Finally the revised recommendations were formally consented (nominal group process) by representatives of relevant societies and organizations including a self-help group. Of originally 4556 hits, 217 studies (4 Cochrane Reviews, 14 meta-analyses, 19 randomized controlled trials, 135 cohort and 45 case-control studies) were included and critically appraised. Grossly unchanged remained the recommendations on avoiding environmental tobacco smoke, breast-feeding over 4 months (alternatively hypoallergenic formulas for children at risk), avoiding a mold-promoting indoor climate, vaccination according to current recommendations, and avoidance of furry pets (especially cats) in children at risk. The recommendation on reducing the house dust mite allergen exposure as a measure of primary prevention was omitted and the impact of a delayed introduction of supplementary food was reduced. New recommendations were adopted concerning fish consumption (during pregnancy / breast-feeding and as supplementary food in the first year), avoidance of overweight, and reducing the exposure to indoor and outdoor air pollutants. The revision of this guideline on a profound evidence basis led to (1) a confirmation of existing recommendations, (2) substantial revisions, and (3) new recommendations. Thereby it is possible

  19. Water-quality assessment of the Albemarle-Pamlico Drainage Basin, North Carolina and Virginia; organochlorine compounds in Asiatic clam (Corbicula fluminea) soft tissues and whole redbrest sunfish (Lepomis auritus) 1992-93

    Science.gov (United States)

    Smith, K.E.; Ruhl, P.M.

    1996-01-01

    The analysis of potential contaminants in biological tissues is an important part of many water-quality assessment programs, including the National Water-Quality Assessment (NAWQA) Program. Tissue analyses often are used to provide information about (1) direct threats to ecosystem integrity, and (2) the occurrence and distribution of potential contaminants in the environment. During 1992-93, Asiatic clam (Corbicula fluminea) soft tissues and whole redbreast sunfish (Lepomis auritus) samples were collected and analyzed to obtain information about the occurrence and distribution of organochlorine compounds in the Albemarle-Pamlico drainage Basin of North Carolina and Virginia. The investigation was conducted as part of the NAWQA Program. Relatively few organochlorine compounds were detected and of the compounds detected, all were detected in relatively low concentrations. The organochlorine compounds detected were p,p'-DDD, p,p'-DDE, p,p'-DDT, dieldrin, trans-nonachlor, PCB's, and toxaphene. Multiple compounds were detected at 16 of 19 sites sampled. Compared to Asiatic clams, redbreast sunfish appear to be better bioindicators of organochlorine contamination in aquatic systems. Except for one detection of toxaphene, pesticide concentrations are well below the National Academy of Sciences and National Academy of Engineering (NAS/NAE) guidelines for the protection of fish-eating wildlife.

  20. Rotating preventers

    International Nuclear Information System (INIS)

    Tangedahl, M.J.; Stone, C.R.

    1992-01-01

    This paper reports that recent changes in the oil and gas industry and ongoing developments in horizontal and underbalanced drilling necessitated development of a better rotating head. A new device called the rotating blowout preventer (RBOP) was developed by Seal-Tech. It is designed to replace the conventional rotating control head on top of BOP stacks and allows drilling operations to continue even on live (underbalanced) wells. Its low wear characteristics and high working pressure (1,500 psi) allow drilling rig crews to drill safely in slightly underbalanced conditions or handle severe well control problems during the time required to actuate other BOPs in the stack. Drilling with a RBOP allows wellbores to be completely closed in tat the drill floor rather than open as with conventional BOPs

  1. Treating and Preventing Burns

    Science.gov (United States)

    ... Healthy Living Healthy Living Healthy Living Nutrition Fitness Sports Oral Health Emotional Wellness Growing Healthy Sleep Safety & Prevention Safety & Prevention Safety and Prevention Immunizations At Home ...

  2. Relapse prevention.

    Science.gov (United States)

    Hall, S M; Wasserman, D A; Havassy, B E

    1991-01-01

    Although knowledge about relapse prevention is still at an early stage, the extant data highlight the importance of several constructs. 1. Motivation for abstinence remains central. The construct itself is often clouded because of its association with mystical notions such as willpower and self-control. We know that manipulation of environmental events can increase motivation. These interventions are effective, however, only as long as the contingencies are in effect. We need to develop and evaluate strategies for transferring contingency management to the natural environment, that is, to institutions and groups that can perpetuate them for the long term. Also, clarification of the kinds of abstinence goals needed to prevent relapse is important. 2. Coping skills have been studied by several investigators, but research on these, except for job-finding skills, is not encouraging. The skills usually taught may be too basic. Skills training oriented to complex targets, such as building nondrug-using networks, may be useful and should be further explored. 3. Social support is clearly important, yet we do not know how best to use it to promote abstinence. The little research available suggests that both familial and nonfamilial systems should be mobilized. We need to define abstinence-promoting supportive behaviors, identify and engage important support systems in treatment, and help patients expand their nondrug-using contacts. 4. Negative affect may be causally related to relapse. We need to continue efforts to identify dysphoric patients and develop interventions to ameliorate dysphoria concurrent with drug abuse treatment (cf. Zweben and Smith 1989). 5. Drug cue reactivity and extinction to drug cues have been demonstrated in the laboratory. What is needed in this promising line of research are (1) investigation of cues and cue-reactivity phenomena in the natural environment or in conditions closely mimicking that environment and (2) extinction methods that transfer

  3. Selective initiation and transmission of disseminated neoplasia in the soft shell clam Mya arenaria dependent on natural disease prevalence and animal size.

    Science.gov (United States)

    Taraska, Norah G; Anne Böttger, S

    2013-01-01

    Disseminated neoplasia, a diffuse tumor of the hemolymph system, is one of the six most destructive diseases among bivalve mollusk populations, characterized by the development of abnormal, rounded blood cells that actively proliferate. Though the specific etiology of disseminated neoplasia in Mya arenaria remains undetermined, the involvement of viral pathogens and/or environmental pollutants has been suggested and considered. The current study used 5-bromodeoxyuridine (BrDU) known to induce the murine leukemia virus and filtered neoplastic hemolymph to initiate disseminated neoplasia in clams from different populations and size classes respectively. M. arenaria from three locations of different natural neoplasia occurrences were divided into a control and three experimental treatments and injected with 200 μl of sterile filtered seawater or 50-200 μg/ml BrDU respectively. In a concurrent experiment, animals from different size classes were injected with 2.5% total blood volume of 0.2 μm filtered blood from a fully neoplastic animal. Animals were biopsied weekly and cell neoplasia development was counted and scored as 0-25, 26-50, 51-75 and 76-100% neoplastic hemocytes (stages 1-4) in 50 μl samples. BrDU injection demonstrated that neoplasia development in M. arenaria was dose dependent on BrDU concentration. In addition, natural disease prevalence at the source location determined initiation of neoplasia induction, with animals from the area of the highest natural disease occurrence displaying fastest neoplasia development (p=0.0037). This could imply that depending on the natural disease occurrence, a potential infectious agent may remain dormant in normal (stage 1) individuals in higher concentrations until activated, i.e. through chemical injection or potentially stress. The size experiment demonstrated that only M. arenaria between 40 and 80 mm developed 26-100% neoplastic hemocytes when injected with filtered neoplastic hemolymph, indicating that

  4. Biodynamic modelling of the bioaccumulation of trace metals (Ag, As and Zn) by an infaunal estuarine invertebrate, the clam Scrobicularia plana

    Energy Technology Data Exchange (ETDEWEB)

    Kalman, J., E-mail: judit.kalman@uca.es [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Smith, B.D. [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Bury, N.R. [Division of Diabetes and Nutritional Science, King' s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH (United Kingdom); Rainbow, P.S. [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom)

    2014-09-15

    Highlights: • Biodynamic modelling is used to predict accumulation of Ag, As and Zn in S. plana. • Dissolved and sediment-associated metals contribute to total metal bioaccumulation. • Relative importance varies with water and sediment concentrations and geochemistries. - Abstract: Biodynamic modelling was used to investigate the uptake and accumulation of three trace metals (Ag, As, Zn) by the deposit feeding estuarine bivalve mollusc Scrobicularia plana. Radioactive labelling techniques were used to quantify the rates of trace metal uptake (and subsequent elimination) from water and sediment diet. The uptake rate constant from solution (±SE) was greatest for Ag (3.954 ± 0.375 l g{sup −1} d{sup −1}) followed by As (0.807 ± 0.129 l g{sup −1} d{sup −1}) and Zn (0.103 ± 0.016 l g{sup −1} d{sup −1}). Assimilation efficiencies from ingested sediment were 40.2 ± 1.3% (Ag), 31.7 ± 1.0% (Zn) and 25.3 ± 0.9% (As). Efflux rate constants after exposure to metals in the solution or sediment fell in the range of 0.014–0.060 d{sup −1}. By incorporating these physiological parameters into biodynamic models, our results showed that dissolved metal is the predominant source of accumulated Ag, As and Zn in S. plana, accounting for 66–99%, 50–97% and 52–98% of total accumulation of Ag, As and Zn, respectively, under different field exposure conditions. In general, model-predicted steady state concentrations of Ag, As and Zn matched well with those observed in clams collected in SW England estuaries. Our findings highlight the potential of biodynamic modelling to predict Ag, As and Zn accumulation in S. plana, taking into account specific dissolved and sediment concentrations of the metals at a particular field site, together with local water and sediment geochemistries.

  5. Polio and Prevention

    Science.gov (United States)

    ... Photo Collections Videos Polio Today → Polio + Prevention Polio + Prevention Polio and prevention Polio is a crippling and ... a child for life. Learn more about polio + prevention The Virus The Vaccines The Communities Related resources ...

  6. Diabetes Prevention Program (DPP)

    Science.gov (United States)

    ... Recruiting Patients & Families Consortia, Networks & Centers Reports & Planning Diabetes Prevention Program (DPP) The NIDDK-sponsored Diabetes Prevention ... Diabetes Prevention Program for those who are eligible. Diabetes Prevention Program (DPP) DPP Goal The DPP looked ...

  7. First genotoxicity study of Paraná river water from Argentina using cells from the clam Corbicula fluminea (Veneroida Corbiculidae and Chinese hamster (Cricetulus griseus Rodentia, Cricetidae K1 cells in the comet assay

    Directory of Open Access Journals (Sweden)

    Jacqueline D. Caffetti

    2008-01-01

    Full Text Available High concentrations of xenobiotics from urban and industrial wastes have contributed to the contamination of many aquatic environments. We used the comet assay to evaluate the genotoxic potential of water collected from the River Paraná, which receives a great deal of waste, at three points (Puerto Piray, Eldorado and Montecarlo in the Misiones Province of Argentina. The in vivo comet assay used 40 freshwater clams (Corbicula fluminea while the in vitro comet assay used Chinese hamster (Cricetulus griseus K1 cell (CHO-K1 cultures with the mutagen ethyl methanesulfonate (EMS as the positive control and phosphate buffered saline (PBS as the negative control. Both assays showed statistically significant differences between the three sampling sites in relation to the negative control, the results of this preliminary study indicating that at these three sites water from the Paraná River presents genotoxic potential.

  8. Vertical distribution, segregation by size and recruitment of the yellow clam Mesodesma mactroides Deshayes, 1854 (Mollusca, Bivalvia, Mesodesmatidae) in exposed sandy beaches of the Rio Grande do Sul state, Brazil.

    Science.gov (United States)

    Bergonci, P E A; Thomé, J W

    2008-05-01

    The vertical distribution and the segregation by size of the yellow clam Mesodesma mactroides Deshayes, 1854 were investigated in the intertidal zone and its limits with the lower and upper shores at exposed sandy beaches of Rio Grande do Sul state, Brazil. The gathering was made throughout 12 months; from the Pinhal beach towards the south of the State, in six 15 km equidistant transects, determined through random selection. In these transects, the calculation of 30 consecutive waves was made in order to determine its average amplitude point (P0), from which two points were marked towards the lower shore (P-1 and P-2) and three towards the upper shore (P1, P2 and P3). A 30 by 50 cm cylinder was buried down to the depth of 40 cm, the material was separated with a 0.25 cm mesh and the specimens were quantified and measured in length. The yellow clam presented segregation by size, especially between recruit and adult individuals, with recruits occupying preferably the zones above P0 and adults from this point towards the sea. The young specimens are distributed through all zones, mixed with adult and recruit specimens, which dismisses the hypothesis of segregation by size in function of competition for space and food, once the burying depth is directly proportional to their length. However, the segregation between recruits and adults might be related to the filtering mechanism of the adults, which could ingest the larva, as well as the fact that the recruits, being small and light, are easily transported to the regions above P0. Seasonal migration was observed for adult individuals during winter and spring, probably associated to the reproduction period of the species, being that the peak of recruitment was greater in the end of the winter and the beginning of spring.

  9. In vitro exposure of haemocytes of the clam Ruditapes philippinarum to titanium dioxide (TiO2) nanoparticles: nanoparticle characterisation, effects on phagocytic activity and internalisation of nanoparticles into haemocytes.

    Science.gov (United States)

    Marisa, Ilaria; Marin, Maria Gabriella; Caicci, Federico; Franceschinis, Erica; Martucci, Alessandro; Matozzo, Valerio

    2015-02-01

    The continuous growth of nanotechnology and nano-industries, the considerable increase of products containing nanoparticles (NPs) and the potential release of NPs in aquatic environments suggest a need to study NP effects on aquatic organisms. In this context, in vitro assays are commonly used for evaluating or predicting the negative effects of chemicals and for understanding their mechanisms of action. In this study, a physico-chemical characterisation of titanium dioxide NPs (n-TiO2) was performed, and an in vitro approach was used to investigate the effects of n-TiO2 on haemocytes of the clam Ruditapes philippinarum. In particular, the effects on haemocyte phagocytic activity were evaluated in two different experiments (with and without pre-treatment of haemocytes) by exposing cells to P25 n-TiO2 (0, 1 and 10 μg/mL). In addition, the capability of n-TiO2 to interact with clam haemocytes was evaluated with a transmission electron microscope (TEM). In this study, n-TiO2 particles showed a mean diameter of approximately 21 nm, and both anatase (70%) and rutile (30%) phases were revealed. In both experiments, n-TiO2 significantly decreased the phagocytic index compared with the control, suggesting that NPs are able to interfere with cell functions. The results of the TEM analysis support this hypothesis. Indeed, we observed that TiO2 NPs interact with cell membranes and enter haemocyte cytoplasm and vacuoles after 60 min of exposure. To the best of our knowledge, this is the first study demonstrating the internalisation of TiO2 NPs into R. philippinarum haemocytes. The present study can contribute to the understanding of the mechanisms of action of TiO2 NPs in bivalve molluscs, at least at the haemocyte level. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Measuring cortisol and DHEA in fingernails: A pilot study

    OpenAIRE

    Seo, Rubo

    2009-01-01

    Fay Warnock1, Kevin McElwee2, Rubo J Seo3, Sean McIsaac3, Danielle Seim3, Tatiana Ramirez-Aponte3, Karine AN Macritchie3, Allan H Young31Developmental Neuroscience and Child Health, BC Children’s Hospital, Vancouver, BC, Canada; 2Department of Dermatology and Skin Science, 3Institute of Mental Health-Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada Purpose: Abnormalities in both cortisol and dehydroepiandrosterone (DHEA) have been reported in psychiatr...

  11. Evaluation of Heavy and Trace Metals in Fingernails of Young ...

    African Journals Online (AJOL)

    WAHAB

    environmental hazards, often as a result of gross inefficiency and negligence. These poor environmental conditions have resulted in increasingly deteriorating health condition as well as drastic reduction in the expectancy, contrary to what obtains in the developed world (Mehra and Juneja, 2005). Nail tissue is rich in.

  12. Examination of Fingernail Contents and Stool for Ova, Cyst and ...

    African Journals Online (AJOL)

    The parasites identified were Ascaris lumbericoides, Taenia species, Giardia lamblia and Entamoeba histolytica. Of the 101 of the stool specimens examined 59(58.4%) were positive for any one parasite and multiple infections were identified in 17.8% of the positive cases. A. lumbricoides 24(23.8%) was found to be the ...

  13. Manganese Concentrations In Hair and Fingernail of Some Kano ...

    African Journals Online (AJOL)

    MICHAEL

    Elevated levels may reflect occupational exposure (Chatt and Katz, 1988). Increased manganese concentrations were found in hair samples of school children scoring poorly in tests to assess general intelligence, visual motor skills, receptive language, verbal memory, non- verbal problem solving and behavioral problems.

  14. Fingernails: Do's and Don'ts for Healthy Nails

    Science.gov (United States)

    ... induced disorders of the nail with update on contemporary nail manicures. The Journal of Clinical and Aesthetic ... Mayo," "Mayo Clinic," "MayoClinic.org," "Mayo Clinic Healthy Living," and the triple-shield Mayo Clinic logo are ...

  15. Stomach (Gastric) Cancer Prevention

    Science.gov (United States)

    ... likely as white men to die from stomach cancer. Stomach Cancer Prevention Key Points Avoiding risk factors and increasing ... factors and increasing protective factors may help prevent stomach cancer. Avoiding cancer risk factors may help prevent certain ...

  16. "AN OUNCE OF PREVENTION..."

    Science.gov (United States)

    HASELKORN, FLORENCE

    PREVENTION AS FUNCTION, VALUE ISSUE, CONCEPTUAL SHORTCOMING, AND PRACTICE IS DISCUSSED AND RELATED TO EDUCATIONAL TASK. PREVENTION AS FUNCTION IS GENERATED BY OUR VALUE PREMISES. IN SEEKING TO PREVENT SOME FORMS OF SOCIAL DYSFUNCTION, WE MAY BE PERPETUATING OTHERS. THE CONCEPT OF PREVENTION IS AMBIGUOUS. CRUCIAL CONCEPTUAL ISSUES INCLUDE THE…

  17. [Prevention of dementia].

    Science.gov (United States)

    Urakami, Katsuya

    2016-03-01

    The dementia prevention consists of three steps, primary prevention of dementia is to prevent from normal and mild cognitive impairment to dementia, secondary prevention is early detection and early treatment of dementia, and tertiary prevention is three stages of progress prevention of dementia. Primary prevention of dementia had been considered impossible until recently, but potential scientific evidence has been shown recently. The fact that 4.62 million people are person with dementia and 400 million people are person with mild cognitive impairment are considered to be urgent problem and we must intend to perform dementia prevention from primary to tertiary prevention thoroughly. We perform dementia screening using touch panel type computer and we recommend person with mild cognitive impairment to join dementia prevention classroom. Therefore, we can prevent progression from mild cognitive impairment to dementia (primary prevention). Early diagnosis and introduction to the specialized medical institution are needed if you find early stage of dementia and treat early (secondary prevention). To prevent progression by the appropriate drug treatment and care for dementia is required (tertiary prevention).

  18. The properties of weft knitted fabric medical and preventive treatment action using eco-raw materials

    Science.gov (United States)

    Halavska, L.; Batrak, O.

    2016-07-01

    A new trend in the world is the clothing production using the new types of ecological raw materials application - milk, pineapple, coconut, hemp, banana, eucalyptus, clams, corn, bamboo, soya, nettle yarn. This makes it possible to create textile materials of new generation with unique antibacterial and antiseptic properties. Such materials have a positive preventive and sometimes therapeutic effect on people, and their health. Eco-raw materials clothing is able to protect the human body from the environment harmful effects: cold, heat, rain, dust, opportunely remove from underclothing layer the steam and gases, sweat; maintain in underclothing layer the necessary microclimate for normal organism functioning. Study of knitwear consumer properties, produced with eco-materials, is an urgent task of the world vector, directed on ecological environmental protection. This paper presents the research results of hygroscopicity and capillarity weft knitted fabrics, what knitted from different types of eco-raw materials: bamboo yarn, yarn containing soybean and nettle yarn. Character of influence of the liquid raising level changes depending on the experiment time and the knitting structure is revealed.

  19. Jet lag prevention

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000719.htm Jet lag prevention To use the sharing features on this page, ... Headache Irritability Stomach upset Sore muscles Tips for Prevention Before your trip: Get plenty of rest, eat ...

  20. Research Areas: Prevention

    Science.gov (United States)

    NCI’s prevention research has a broad focus, from identifying environmental and lifestyle factors that influence cancer risk to studying the biology of how cancer develops and studying ways to disseminate prevention interventions.

  1. Marine Pollution Prevention Act

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Pollution Prevention Act of 2008 implements the International Convention for the Prevention of Pollution from Ships, including related Protocols (MARPOL)...

  2. Preventing Type 2 Diabetes

    Science.gov (United States)

    ... Sexual & Urologic Problems Clinical Trials Preventing Type 2 Diabetes Perhaps you have learned that you have a ... I lower my chances of developing type 2 diabetes? Research such as the Diabetes Prevention Program shows ...

  3. Preventing Diabetes Problems

    Science.gov (United States)

    ... Problems Diabetes & Sexual & Urologic Problems Clinical Trials Preventing Diabetes Problems View or Print All Sections Heart Disease & ... prevent or delay sexual and urologic problems. Depression & Diabetes Depression is common among people with a chronic, ...

  4. Statins and Cancer Prevention

    Science.gov (United States)

    ... cell membrane integrity, cell signaling, protein synthesis, and cell cycle progression, all of which are potential areas of intervention to arrest the cancer process. What are the ... at the NCI Division of Cancer Prevention Web site at http://prevention. ...

  5. Preventing food poisoning

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/007441.htm Preventing food poisoning To use the sharing features on this page, please enable JavaScript. To prevent food poisoning , take the following steps when preparing food: Carefully ...

  6. Breast Cancer Prevention

    Science.gov (United States)

    ... of Breast & Gynecologic Cancers Breast Cancer Screening Research Breast Cancer Prevention (PDQ®)–Patient Version What is prevention? Go ... from starting. Risk-reducing surgery . General Information About Breast Cancer Key Points Breast cancer is a disease in ...

  7. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... Peer Counseling Blog About Media Donate Spinal Cord Injury Medical Expert Videos Topics menu Topics Preventing Pressure Sores Adult Injuries Spinal Cord Injury 101 David Chen, MD Preventing ...

  8. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... Injury Medical Expert Videos Topics menu Topics Preventing Pressure Sores Adult Injuries Spinal Cord Injury 101 David Chen, MD Preventing Pressure Sores Mary Zeigler, MS Transition from Hospital to ...

  9. Traditional preventive treatment options

    DEFF Research Database (Denmark)

    Longbottom, C; Ekstrand, K; Zero, D

    2009-01-01

    Preventive treatment options can be divided into primary, secondary and tertiary prevention techniques, which can involve patient- or professionally applied methods. These include: oral hygiene (instruction), pit and fissure sealants ('temporary' or 'permanent'), fluoride applications (patient...... options....

  10. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... L Sarah Harrison, OT Anne Bryden, OT The Role of the Social Worker after Spinal Cord Injury ... do to prevent pressure sores? play_arrow What role does diet and hydration play in preventing pressure ...

  11. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... to prevent pressure sores? play_arrow What is “skin tolerance” and how can it be ... play_arrow What role does diet and hydration play in preventing pressure sores among ...

  12. National Suicide Prevention Lifeline

    Science.gov (United States)

    ... Our Crisis Centers Stories of Hope and Recovery Mental Health & Suicide Prevention Glossary Get Involved Participate Our Crisis Centers Social Media Hub Promote National Suicide Prevention Month Providers & Professionals ...

  13. Prevention of gravitational collapse

    International Nuclear Information System (INIS)

    Moffat, J.W.; Taylor, J.G.

    1981-01-01

    We apply a new theory of gravitation to the question of gravitational collapse to show that collapse is prevented in this theory under very reasonable conditions. This result also extends to prevent ultimate collapse of the Universe. (orig.)

  14. Accident prevention in radiotherapy.

    Science.gov (United States)

    Holmberg, O

    2007-04-01

    In order to prevent accidents in radiotherapy, it is important to learn from accidents that have occurred previously. Lessons learned from a number of accidents are summarised and underlying patterns are looked for in this paper. Accidents can be prevented by applying several safety layers of preventive actions. Categories of these preventive actions are discussed together with specific actions belonging to each category of safety layer.

  15. Accident prevention in radiotherapy

    OpenAIRE

    Holmberg, O

    2007-01-01

    In order to prevent accidents in radiotherapy, it is important to learn from accidents that have occurred previously. Lessons learned from a number of accidents are summarised and underlying patterns are looked for in this paper. Accidents can be prevented by applying several safety layers of preventive actions. Categories of these preventive actions are discussed together with specific actions belonging to each category of safety layer.

  16. Prevention of periodontal diseases.

    Science.gov (United States)

    Dentino, Andrew R; Kassab, Moawia M; Renner, Erica J

    2005-07-01

    The ultimate goal of periodontal disease prevention is to maintain the dentition over a lifetime in a state of health, comfort, and function in an aesthetically pleasing presentation. This article focuses on primary and secondary periodontal disease prevention as they relate to gingivitis and periodontitis. Risk assessment, mechanical plaque control, chemical plaque control, current clinical recommendations for optimal prevention, and future preventive strategies are discussed.

  17. Fall Prevention: Simple Tips to Prevent Falls

    Science.gov (United States)

    ... bars for the shower or tub A sturdy plastic seat for the shower or tub — plus a ... healthy-lifestyle/healthy-aging/in-depth/fall-prevention/art-20047358 . Mayo Clinic Footer Legal Conditions and Terms ...

  18. Chickenpox Prevention and Treatment

    Science.gov (United States)

    ... Multimedia Related Links Medline Plus Healthfinder.gov Shingles Prevention & Treatment Language: English Español (Spanish) Recommend on Facebook ... Prescribed by Your Doctor Español: Prevención y tratamiento Prevention The best way to prevent chickenpox is to ...

  19. Prevention IS Care

    Centers for Disease Control (CDC) Podcasts

    2009-03-26

    This podcast provides an overview of the Prevention IS Care campaign, which provides HIV prevention tools for medical care providers to use on a daily basis with patients who are living with HIV.  Created: 3/26/2009 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 3/26/2009.

  20. Strategies to prevent loneliness

    NARCIS (Netherlands)

    de Jong Gierveld, J.; Fokkema, T.; Sha'ked, A.; Rokach, A.

    2015-01-01

    Prevention is better than cure’. This also applies to loneliness experiences: preventing people from loneliness is better than helping them to reduce their feelings of loneliness through interventions. In this chapter, we argue the necessity of loneliness prevention strategies for handling future

  1. Prevention of Food Poisoning.

    Science.gov (United States)

    Army Quartermaster School, Ft. Lee, VA.

    The programed text provides a single lesson, four-hour, correspondence subcourse on the prevention of food poisoning. It covers the following areas: a definition of food poisoning; chemical food poisoning; biological food poisoning; causes and prevention of trichinosis; six factors controlling bacteria growth; bacterial infection; prevention of…

  2. Cancer risks and prevention

    International Nuclear Information System (INIS)

    Vessey, M.P.; Gray, M.

    1985-01-01

    A series of essays in honour of Sir Richard Doll is presented. Chapters cover the preventability of cancer, geography, smoking, diet, occupation, radiation, infections and immune impairment, exogenous and endogenous hormones, other drugs, prevention through legislation and by education and cancer risks and prevention in the Third World. The chapter on radiation has been indexed separately. (UK)

  3. Sunburn: Treatment and Prevention

    Science.gov (United States)

    ... 12 mos.) Toddler 1-3yrs. Preschool 3-5yrs Grade School 5-12yrs. Teen 12-18yrs. Young Adult 18-21yrs. Healthy Living Healthy Living Healthy Living Nutrition Fitness Sports Oral Health Emotional Wellness Growing Healthy Sleep Safety & Prevention Safety & Prevention Safety and Prevention Immunizations ...

  4. [Prevention of eating disorders].

    Science.gov (United States)

    Papežová, Hana

    2017-01-01

    The quality of the prevention of eating disorders represents in several last decades frequently discussed issue in the context of rapidly changing socio-economic conditions, a significant increase of influence of the media, new technologies and knowledge of risk factors. Primary prevention aims to reduce the risk of developing eating disorders, but secondary and tertiary prevention play the important role as well. Effective and coordinated prevention is still missing. Our experience of international cooperation of the last 20 years led to the development and evaluation of prevention programs. We are describing their fast development and ongoing programs following the new trends recommended by WHO.

  5. Prevalência da infecção por clamídia e gonococo em gestantes de seis cidades brasileiras Prevalence of Chlamydia and Neisseria gonorrhoeae infections in pregnant women in six Brazilian cities

    Directory of Open Access Journals (Sweden)

    Emilia Moreira Jalil

    2008-12-01

    Full Text Available OBJETIVO: este trabalho buscou estimar a prevalência das infecções pela Chlamydia trachomatis e pela Neisseria gonorrhoeae em gestantes de seis cidades brasileiras e identificar sua associação com variáveis socioeconômicas e demográficas. MÉTODOS: este estudo faz parte de uma pesquisa multicêntrica, de âmbito nacional, transversal, com amostra de gestantes atendidas entre 2004 e 2005 nos serviços de pré-natal da atenção básica de seis cidades brasileiras (Manaus, Fortaleza, Goiânia, Rio de Janeiro, São Paulo e Porto Alegre. Amostras cérvico-vaginais foram coletadas de todas as gestantes e submetidas posteriormente à técnica de captura híbrida para identificação da clamídia e do gonococo. As informações sociodemográficas, médicas, sexuais e obstétricas foram coletadas por meio de questionários específicos. Para avaliar os fatores de risco associados à infecção por gonorréia e clamídia, foi utilizado o Odds Ratio (OR. A análise estatística foi feita com a utilização do teste t de Student, o χ2 e o teste exato de Fischer. RESULTADOS: foram recrutadas 3.303 gestantes, cuja idade média foi 23,8 anos (±6,9. As prevalências da infecção por clamídia e pelo gonococo foram, respectivamente, 9,4 e 1,5%. Dez por cento das gestantes com infecção por clamídia apresentaram presença simultânea do gonococo. O risco de apresentar uma dessas infecções foi duas vezes maior para as gestantes com menos de 20 anos. Os principais preditores da infecção foram: idade menor de 20 anos, raça/cor negra, ser solteira ou separada e relato de mais de um parceiro no último ano. CONCLUSÕES: este estudo observou prevalências elevadas da infecção pela Chlamydia trachomatis e pela Neisseria gonorrhoeae em gestantes brasileiras. O principal fator de risco para a infecção foi ter menos de 20 anos de idade.PURPOSE: This paper has aimed at estimating the prevalence of infections by Chlamydia trachomatis and by Neisseria

  6. Prevention Of Stroke

    Directory of Open Access Journals (Sweden)

    Nagaraja D

    2005-01-01

    Full Text Available Stroke is an important cause for neurological morbidity and mortality. Prevention of ischemic stroke involves identification and prevention of risk factors and optimal use of pharmacotherapy. Risk factors have been classified as modifiable and non-modifiable; control of modifiable factors should prevent stroke occurrence. Stroke prevention has been described at three levels: primary, secondary and tertiary. Prolonged hypertension increases an individual′s risk for developing fatal or nonfatal stroke by three times and its control has been shown to prevent stroke. Diabetes mellitus is an important cause for microangiopathy and predisposes to stroke. Statin trials have shown significant reduction in stroke in those who were treated with statins. Stroke risk can be reduced by avoiding tobacco use, control of obesity and avoiding sedentary life style. Anti platelet medications are effective for secondary prevention of stroke. Educating society regarding modifiable risk factors and optimal use of pharmacotherapy form the cornerstone for the prevention of stroke.

  7. Prevention of suicide

    Directory of Open Access Journals (Sweden)

    Rajiv Gupta

    2017-01-01

    Full Text Available Suicide is a major public health problem in India, probably even bigger than in the West. Suicidal behavior is the best conceptualized as a multifaceted complex problem involving social factors and mental illnesses. Broadly, there are two approaches to suicide prevention; population preventive strategies and high-risk preventive strategies. Population preventive strategies include reducing availability of means for suicide, education of primary care physicians, influencing media portrayal of suicidal behavior, education of the public, telephone helplines, and addressing economic issues associated with suicidal behavior. High-risk preventive strategy includes identifying individuals with high risk of committing suicide, intensively treating mental illness if present, and providing psychosocial support. Thus, prevention requires a multipronged effort with collaboration from various sectors including mental health professionals, social justice department, and macroeconomic policy makers.

  8. Traditional preventive treatment options

    DEFF Research Database (Denmark)

    Longbottom, C; Ekstrand, K; Zero, D

    2009-01-01

    conventional operative care, and since controlling the caries process prior to first restoration is the key to breaking the repair cycle and improving care for patients, future research should address the shortcomings in the current level of supporting evidence for the various traditional preventive treatment......Preventive treatment options can be divided into primary, secondary and tertiary prevention techniques, which can involve patient- or professionally applied methods. These include: oral hygiene (instruction), pit and fissure sealants ('temporary' or 'permanent'), fluoride applications (patient...

  9. Prevention of Prosthetic Dentistry

    Directory of Open Access Journals (Sweden)

    Eremin O.V.

    2011-03-01

    Full Text Available Prevention in prosthetic dentistry is not just a regular oral hygiene and the prevention of caries in the early stages of its development. The initial goal of orthopedic and dental should be the ability to convey to the patient's sense of pros-thetics that proteziruya one saved more. An example is included prosthetic dental arch defects with bridges or single artificial crowns on implants that will prevent movement of teeth and the continuity of the dentition

  10. Prevent Infections During Chemotherapy

    Centers for Disease Control (CDC) Podcasts

    2011-10-24

    This podcast discusses the importance of preventing infections in cancer patients who are undergoing chemotherapy. Dr. Lisa Richardson, CDC oncologist, talks about a new Web site for cancer patients and their caregivers.  Created: 10/24/2011 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP), Division of Cancer Prevention and Control (DCPC).   Date Released: 10/24/2011.

  11. Preventing food allergy

    DEFF Research Database (Denmark)

    de Silva, Debra; Panesar, Sukhmeet S; Thusu, Sundeep

    2013-01-01

    The European Academy of Allergy and Clinical Immunology is developing guidelines about how to prevent and manage food allergy. As part of the guidelines development process, a systematic review is planned to examine published research about the prevention of food allergy. This systematic review...... recommendations. The aim of this systematic review will be to assess the effectiveness of approaches for the primary prevention of food allergy....

  12. Speech disorder prevention

    Directory of Open Access Journals (Sweden)

    Miladis Fornaris-Méndez

    2017-04-01

    Full Text Available Language therapy has trafficked from a medical focus until a preventive focus. However, difficulties are evidenced in the development of this last task, because he is devoted bigger space to the correction of the disorders of the language. Because the speech disorders is the dysfunction with more frequently appearance, acquires special importance the preventive work that is developed to avoid its appearance. Speech education since early age of the childhood makes work easier for prevent the appearance of speech disorders in the children. The present work has as objective to offer different activities for the prevention of the speech disorders.

  13. Work hazard prevention plans

    International Nuclear Information System (INIS)

    Albertos Campos, F.

    2009-01-01

    The prevention of industrial risks is a constantly evolving discipline that has changed considerable in the last 25 years. The Cofrentes Nuclear Power Plants has always been operated with a clear policy favoring prevention by supporting the principle of its integration, i. e., that the hierarchical functional organization of the company make sure that industrial risk prevention is effective and that health and safety standards are met. The historical evolution of occupational safety in the Cofrentes Nuclear Power Plant shows a a clear trend towards improvement and is the results of many years of hard work and effort by the plants own and contractor personnel in the field of industrial risk prevention. (Author)

  14. Fungus Infections: Preventing Recurrence

    Science.gov (United States)

    ... Favorite Name: Category: Share: Yes No, Keep Private Fungus Infections: Preventing Recurrence Share | Doctors have excellent treatments for skin fungus infections that occur on the feet, nails, groin, ...

  15. Prevention at Community Colleges. Prevention Update

    Science.gov (United States)

    Higher Education Center for Alcohol, Drug Abuse, and Violence Prevention, 2012

    2012-01-01

    According to "Community College Student Alcohol Use: Developing Context-Specific Evidence and Prevention Approaches," community colleges have traditionally had a threefold mission that includes preparing students for transfer to four-year colleges, developmental education, and workforce preparation. The researchers point out that the demographic…

  16. Preventing Eye Injuries

    Science.gov (United States)

    ... Stories Español Eye Health / Eye Health A-Z Eye Injuries Sections Preventing Eye Injuries Recognizing and Treating ... Infographic Five Steps to Safer Champagne Celebrations Preventing Eye Injuries Leer en Español: Lesiones de los ojos ...

  17. Injury prevention in football

    African Journals Online (AJOL)

    and cool downs before and after training and matches, respectively. As part of injury prevention, adequate injury management and rehabilitation are essential; especially in the prevention of re-injury. Unfortunately, youth football is often disadvantaged with inadequate or unavailable sports medicine personnel and treatment ...

  18. HIV Risk and Prevention

    Science.gov (United States)

    ... Prevention VIH En Español Get Tested Find an HIV testing site near you. Enter ZIP code or city Follow HIV/AIDS CDC HIV CDC HIV/AIDS See RSS | ... Email Updates on HIV Syndicated Content Website Feedback HIV Risk and Prevention Recommend on Facebook Tweet Share ...

  19. Preventative Medicine today

    Directory of Open Access Journals (Sweden)

    José Antonio Maluf de Carvalho

    2005-03-01

    Full Text Available The great majority of chronic diseases can be prevented byreducing risks, understood as factors that increase the probabilityof a specific disease or condition, such as hypertension,hypercholesterolemia, inadequate diet, smoking habit, obesity andsedentarism. These aspects are evaluated in this article as wellas prevention and screening methods.

  20. [Prevention of psychosocial risks].

    Science.gov (United States)

    Dalle, Édouard; Trichard-Salembier, Alexandra; Sobaszek, Annie

    2018-02-01

    The theme of psychosocial risks remains in the workplace. It is therefore essential that all members of a company are made aware of the terminology and specific prevention actions in this field. Distinguishing between the manifestations of these risks and their causes and consequences helps to improve prevention. Copyright © 2017 Elsevier Masson SAS. All rights reserved.