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Sample records for water clam corbicula

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

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    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.

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

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    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.

  3. Dynamic changes in the accumulation of metabolites in brackish water clam Corbicula japonica associated with alternation of salinity.

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    Koyama, Hiroki; Okamoto, Seiji; Watanabe, Naoki; Hoshino, Naoshige; Jimbo, Mitsuru; Yasumoto, Ko; Watabe, Shugo

    2015-03-01

    The brackish water clam Corbicula japonica inhabits rivers and brackish waters throughout Japan where the major fishing grounds in the Ibaraki Prefecture, Japan, are located at the Hinuma Lake and Hinuma River. Water salinity in the Lake Hinuma is low and stable due to the long distance from the Pacific Ocean, whereas that in the downstream of the river varies daily due to a strong effect of tidal waters. In the present study, we dissected the gill and foot muscle of brackish water clam collected from these areas, and subjected them to metabolome analysis by capillary electrophoresis-time-of-flight mass spectrometry. More than 200 metabolites including free amino acids, peptides and organic acids were identified, and their amounts from the foot muscle tend to be higher than those from the gill. The principal component analysis revealed that the amount of each metabolite was different among sampling areas and between the gill and foot muscle, whereas no apparent differences were observed between male and female specimens. When the metabolites in the female clam at high salinity were compared with those at low salinity, concentrations of β-alanine, choline, γ-aminobutyric acid, ornithine and glycine betaine were found to be changed in association with salinity. We also compared various metabolites in relation to metabolic pathways, suggesting that many enzymes were involved in their changes depending on salinity. Copyright © 2014 Elsevier Inc. All rights reserved.

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

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    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.

  5. Influence of temperature, pH, oxygenation, water-type and substrate on biomarker responses in the freshwater clam Corbicula fluminea (Müller).

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    Vidal, Mary-Laure; Bassères, Anne; Narbonne, Jean-François

    2002-05-01

    We investigated the influence of abiotic factors on responses of components of detoxification metabolism of phases I and II, indicators related to oxidative stress and propionylcholinesterase, proposed as biomarkers of pollution in Corbicula fluminea. Combined effects of temperature (10 and 20 degrees C), water-type (water purified by reverse-osmosis, lake water from the collection site and tap water) and habitat substrate (presence and absence of sand) were assessed in a five-day experiment. Additionally, clams were exposed to hypoxia or submitted to acidic, neutral or alkaline conditions at 20 degrees C, in lake water, without sand, for five days. Responses of biomarkers were generally higher when clams were placed in tap water, except for level of peroxidised lipids (PL). Catalase (CAT) and NADH-cytochrome c reductase (NADH-red.) activities increased whereas propionylcholinesterase (PChE) activity decreased in absence of sand. Decreasing temperature resulted in depressing PChE and NADPH-cytochrome c reductase (NADPH-red.) activities. Hypoxia induced an increase of CAT activity and glutathione S-transferase activity towards ethacrynic acid and a decrease of PL level. CAT and NADH-red. activities as well as PL level were reduced when clams were exposed to acidic and/or alkaline conditions. These results indicate that effects of abiotic factors should be taken into account in environmental studies.

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

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    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...

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

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    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.

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

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

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    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.

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

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

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    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

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

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    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.

  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

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    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. 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

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    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.

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

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    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.

  17. 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.

  18. Associated macrozoobenthos with the invasive Asian clam Corbicula fluminea

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    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.

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

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    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.

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

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

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    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.

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

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    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.

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

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    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

  4. 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.

  5. 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.

  6. 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.

  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. 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.

  9. Influence of the asian clam Corbicula fluminea (bivalvia : corbiculidae) on estuarine epibenthic assemblages

    OpenAIRE

    Ilarri, Martina I.; Souza,A. T.; Antunes, C.; Guilhermino, Lúcia; Sousa, Ronaldo Gomes de

    2014-01-01

    Supplementary data related to this article can be found at: http:// dx.doi.org/10.1016/j.ecss.2014.03.017 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 infl...

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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.

  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. 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.

  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. 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.

  1. 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.

  2. 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.

  3. A study of Edwardsiella tarda colonizing live Asian clam, Corbicula fluminea, from Pasir Mas, Kelantan, Malaysia with the emphasis on its antibiogram, heavy metal tolerance and genetic diversity.

    OpenAIRE

    Wei, Lee Seong; Wee, Wendy; Che Manan, Zalina; Amin, Md. Ruhul; Hajisamae, Sukree

    2013-01-01

    This paper deals with the antibiogram, heavy metal tolerance and genetic properties of Edwardsiella tarda colonizing live Asian Clam, Corbicula fluminea from Pasir Mas, Kelantan, Malaysia. Asian Clam is a popular snack for Malaysians. An antibiotic susceptibility test was carried out using the disc diffusion method against 19 types of antibiotics, namely: oxolinic acid, ampicillin, erythromycin, lincomycin, oleandomycin, amoxicillin, colistin sulphate, sulfamethoxazole, chloramphenicol, doxyc...

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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)

  15. 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.

  16. 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

  17. 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.

  18. [Impacts of Asian clams (Corbicula fluminea) on lake sediment properties and phosphorus movement].

    Science.gov (United States)

    Zhang, Lei; Gu, Xiao-Zhi; Shao, Shi-Guang; Hu, Hai-Yan; Zhong, Ji-Cheng; Fan, Cheng-Xin

    2011-01-01

    To examine the impact of Corbicula fluminea on sediment properties and phosphorus dynamics across sediment-water interface in lake, the microcosm experiment was carried out with sediment and lake water from the estuary of Dapu River, a eutrophic area in Taihu Lake. Rhizon samplers were used to acquire pore water, and soluble reactive phosphorus (SRP) flux across sediment-water interface and sediment properties were determined. The activity of C. fluminea destroyed the initial sediment structure, mixed sediment in different depths, increased oxygen penetration depth, sediment water content, and total microbial activity in sediment. The downward movement of overlying water was enhanced by the activity of C. fluminea, which decreased Fe2+ in pore water by oxidation. The production of ferric iron oxyhydroxide adsorbed SRP from pore water and decreased SRP concentration in pore water, and this increased iron bound phosphorus in corresponding sediment. The emergence of C. fluminea accelerated SRP release from sediment to overlying water, and enhanced SRP flux increased with the rise of introduced C. fluminea density. Metabolization of C. fluminea might play an important role in accelerating SRP release.

  19. Interactions of Corbicula sp. with power plants. [Power plant condenser fouling by clams, use of waste heat for control of fouling by clams, and use of thermal effluents in clam aquaculture

    Energy Technology Data Exchange (ETDEWEB)

    Mattice, J.S.

    1977-01-01

    There are three perspectives with which to view the interaction of Corbicula and power plants: as a fouling agent; as an important part of the natural ecosystem; and as a potential species for use in waste heat aquaculture. The first two of these interactions are essentially negative in character, since they involve avoidance of impacts either of Corbicula on power plant operation or of power plant operation on Corbicula. Condenser fouling by these claims has been controlled by mechanical means or by continuous chlorination. Our data support the potential for using heated water to control fouling and a model for determining required thermal dosing is presented. Preliminary data also indicate potential for control by combining simultaneous short-term exposure to hot water and chlorine. The third of the interactions is essentially positive in character. The use of thermal effluents in Corbicula aquaculture systems is proposed.

  20. 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.

  1. 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

  2. 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.

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

    Science.gov (United States)

    Liao, Chung-Min; Jou, Li-John; Chen, Bo-Ching

    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.

  4. 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. A.; Peterson, J.T.; Unrine, J.M.; Rickard, J.; Black, M.C.

    2009-01-01

    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, USA). 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. ?? 2009 SETAC.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. A real-time biomonitoring system to detect arsenic toxicity by valve movement in freshwater clam Corbicula fluminea.

    Science.gov (United States)

    Chen, Wei-Yu; Jou, Li-John; Chen, Suz-Hsin; Liao, Chung-Min

    2012-05-01

    Arsenic (As) is the element of greatest ecotoxicological concern in aquatic environments. Effective monitoring and diagnosis of As pollution via a biological early warning system is a great challenge for As-affected regions. The purpose of this study was to synthesize water chemistry-based bioavailability and valve daily rhythm in Corbicula fluminea to design a biomonitoring system for detecting waterborne As. We integrated valve daily rhythm dynamic patterns and water chemistry-based Hill dose-response model to build into a programmatic mechanism of inductance-based valvometry technique for providing a rapid and cost-effective dynamic detection system. A LabVIEW graphic control program in a personal computer was employed to demonstrate completely the functional presentation of the present dynamic system. We verified the simulated dissolved As concentrations based on the valve daily rhythm behavior with published experimental data. Generally, the performance of this proposed biomonitoring system demonstrates fairly good applicability to detect waterborne As concentrations when the field As concentrations are less than 1 mg L(-1). We also revealed that the detection times were dependent on As exposure concentrations. This biomonitoring system could particularly provide real-time transmitted information on the waterborne As activity under various aquatic environments. This parsimonious C. fluminea valve rhythm behavior-based real-time biomonitoring system presents a valuable effort to promote the automated biomonitoring and offers early warnings on potential ecotoxicological risks in regions with elevated As exposure concentrations.

  14. 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.

  15. 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.

  16. 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.

  17. Assessment of diazinon toxicity in sediment and water of constructed wetlands using deployed Corbicula fluminea and laboratory testing.

    Science.gov (United States)

    Bouldin, J L; Farris, J L; Moore, M T; Smith, S; Cooper, C M

    2007-08-01

    Constructed wetlands for mitigation of nonpoint agricultural runoff have been assessed for their ability to decrease potential toxicity from associated contaminants. After a simulated runoff event, constructed wetlands positioned in series were used to measure the effects of the organophosphate insecticide diazinon. Water, sediment, and plant samples from five sites were analyzed for diazinon concentrations from 0.5 hours to 26 days; peak concentrations were measured in sediment after 0.5 hours (268.7 microg/kg) and in water and plant tissue after 3 hours (121.71 microg/L and 300.7 microg/kg, respectively). Cholinesterase activity and changes in shell growth were measured from Corbicula fluminea deployed at corresponding sites. Water collected after 9 hours from all wetland sites contained diazinon concentrations sufficient to cause toxicity to Ceriodaphnia dubia, but not to Pimephales promelas. C. dubia survival was decreased in water sampled through 7 days from the site nearest runoff introduction, whereas C. fluminea deployed at this same site experienced 100% mortality after 26 days. Clams from lower sites survived wetland conditions, but growth and ChE activity were significantly decreased lower than that of clams from a control site. C. dubia exposed to water from these sites continued to have decreased survival throughout the 26-day sampling. Sediment sampled from 48 hours through 14 days at the lowest wetland site decreased the laboratory survival of Chironomus dilutus, and sediment from upper sites elicited an effect only on day 26. Although wetland concentrations of aqueous diazinon were decreased lower than toxic thresholds after 26 days, decreased ChE activity in deployed clams provided evidence of residual diazinon effects to deployed organisms.

  18. Bioaccumulation and metallothionein response in the Asiatic clam (Corbicula fluminea) after experimental exposure to cadmium and inorganic mercury

    Energy Technology Data Exchange (ETDEWEB)

    Baudrimont, M.; Metivaud, J.; Maury-Brachet, R.; Ribeyre, F.; Boudou, A. [Univ. Bordeaux I/CNRS, Talence (France). Lab. d`Ecotoxicologie

    1997-10-01

    The involvement of metallothioneins (MTs) in cadmium (Cd) and inorganic mercury (Hg[II]) bioaccumulation by the freshwater bivalve Corbicula fluminea was experimentally investigated after 0, 15, 30 and 45 d of exposure from the water column source. Three levels of contamination were studied for each metal: 0, 5, and 35 {micro}g Cd/L and 0, 1.45, and 5 {micro}g Hg/L, with two replicates per condition. Forty eight experimental units (EUs) were conducted simultaneously. The mollusks were fed twice a week by additions of phytoplanktonic algae. Quantification of MTs was done by Hg-saturation assay, using cold Hg(II). A partial purification of these proteins was conducted by gel-filtration chromatography, followed by Cd determinations in the different eluted fractions. Results at the whole organism (soft tissues) and organ or tissue group (gills, mantle, foot, visceral mass) levels show high metal concentrations, with a fourfold greater accumulation of inorganic Hg than Cd after 30 d exposure at the same concentration of 5 {micro}g/L. Gills and visceral mass were the principal storage compartments. A significant increase in MT concentrations was revealed in these two organs after exposure to Cd: ratios between the MT concentrations in contaminated and control mollusks were 2.4 and 2.8, respectively, for 5 and 35 {micro}g Cd/L. Cd burdens in the cytosol and in {le}18-kDa protein fractions, similar to purified mammal MTs, correspond to 30 and 14% of the total Cd accumulated in the whole organisms. No significant increase in MT biosynthesis was observed after exposure to inorganic Hg, despite the high metal concentrations in the organs.

  19. Genetic damage in the bivalve mollusk Corbicula fluminea induced by the water-soluble fraction of gasoline.

    Science.gov (United States)

    Fedato, R P; Simonato, J D; Martinez, C B R; Sofia, S H

    2010-07-19

    Although gasoline is an important contaminant of aquatic ecosystems, information concerning the potential effects of this petroleum derivative on the DNA of aquatic biota is lacking. The present study aimed to evaluate the genotoxic and mutagenic effects of acute exposures (6, 24, and 96h) to gasoline water-soluble fraction (GWSF), diluted to 5%, on the Asian clam Corbicula fluminea. The comet assay and the micronucleus (MN) test were performed on hemocytes and gill cells of C. fluminea. For the three different times tested, the comet assay indicated DNA damage in hemocytes and gill cells of C. fluminea exposed to GWSF. The MN test detected significant damage in the genetic material of the hemocytes only after 96h of exposure to GWSF. The recovery capacity of organisms previously exposed for 6h to GWSF was also evaluated with the comet assay. The results revealed a great capacity of this species to repair DNA damage; following 6h of recovery, the comet score returned to that of the control groups. Overall, our findings indicate that GWSF has genotoxic and mutagenic effects on C. fluminea. In addition, the present results confirm the sensitivity of C. fluminea to damage caused by exposure to environmental contaminants, and, therefore, its suitability for use in environmental monitoring studies. Copyright 2010 Elsevier B.V. All rights reserved.

  20. 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.

  1. Colonization of the German part of the river Rhine by the Asiatic clam, Corbicula fluminea Müller, 1774 (Pelecypoda, Corbiculidae)

    NARCIS (Netherlands)

    NN,

    1991-01-01

    The freshwater bivalve Corbicula fluminea (Müller, 1774), new to the aquatic fauna of the Federal Republic of Germany, is recorded for the first time on four localities in the German part of the River Rhine.

  2. Integrated biomarker responses of the invasive species Corbicula fluminea in relation to environmental abiotic conditions: a potential indicator of the likelihood of clam's summer mortality syndrome.

    Science.gov (United States)

    Oliveira, Cristiana; Vilares, Pedro; Guilhermino, Lúcia

    2015-04-01

    The aim of this study was to investigate the variation of several biomarkers in wild populations of Corbicula fluminea in relation to abiotic condition changes to identify environmental factors associated with increased stress in this species potentially leading to massive mortality events. The study was carried out from July to October in the freshwater tidal areas of the estuaries of Minho and Lima Rivers (NW Iberian Peninsula). Monthly, 7 biomarkers (biotransformation, energy production, anti-oxidant defenses and lipid peroxidation damages) were determined in C. fluminea and 17 abiotic parameters were determined in water or sediments in 4 sampling sites: M1, M2 and M3 in Minho (up=> downstream); and L in Lima estuaries. The results of biomarkers were integrated using the Integrated Biomarker Response (IBR), Index and also analysed in relation to environmental parameters by Redundancy Analysis (RDA). Overall, the findings of the present study indicate that July and August are particularly stressful months for the studied C. fluminea populations, especially at downstream sites; the increase of nutrients and ammonium water concentrations, water temperature and conductivity are major contributors for this increased stress; the biomarkers indicated that in July/August C. fluminea is exposed to oxidative stress inducers, environmental chemical contaminants biotransformed by esterases and glutathione S-transferase enzymes, and that organisms need additional energy to cope with the chemical and/or thermally-induced stress. The findings of the present study stress the importance of biomonitoring the health condition of C. fluminea because it may allow determining the likelihood of summer/post summer mortality syndrome in this species. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Assessment of Lemna minor (duckweed) and Corbicula fluminea (freshwater clam) as potential indicators of contaminated aquatic ecosystems: responses to presence of psychoactive drug mixtures.

    Science.gov (United States)

    Mohamed, Bourioug; Jean-Yves, Mazzitelli; Pierre, Marty; Hélène, Budzinski; Aleya, Lotfi; Elsa, Bonnafé; Florence, Geret

    2017-01-31

    The pharmaceutical products are emerging pollutants continuously released into the environment, because they cannot be effectively removed by the wastewater treatment plants. In recent years, questions have been raised concerning the environmental risks related to these pollutants. The goal of this research was to evaluate the responses in Lemna minor after 7 days and in Corbicula fluminea after differing durations (1, 3, 7, and 19 days) of exposure to the psychoactive drug mixture (valproic acid, citalopram, carbamazepine, cyamemazine, hydroxyzine, oxazepam, norfluoxetine, lorazepam, fluoxetine, and sertraline) in different concentrations (0, 0 + ethanol, drug concentration (DC) 1 = river water concentration, DC2 = effluent concentration, and DC3 = 10× effluent concentration). In this aim, growth parameters of L. minor, gluthathione S-transferase (GSTs), catalase (CAT), ethoxyresorufin-O-deethylase (EROD) and/or gene expressions (pi-gst, cat, cytochrome P450 4 (cyp4), multidrug resistant 1 (mdr1), and superoxide dismutase (sod)) were measured. GST activities increased significantly in L. minor exposed to DC3, but no changes were found in CAT activity. In C. fluminea, EROD activity was induced significantly in both gill and digestive gland tissues after 3 days' exposure to DC3, while a GST increase was observed only in digestive gland tissues, suggesting that these pharmaceuticals induced an oxidative effect. Gene expression analysis revealed transient transcriptomic responses of cyp4, sod, and mdr1 under drug concentrations 2 or 3 and no change of expression for the other genes (cat and pi-gst) or condition (environmental drug concentration) tested. Finally, the data reported in this study represent important ecotoxicological information, confirming that this enzyme family (cyp4, sod, and mdr1) may be considered as a sensible and early indicator of exposure to drugs and emphasizing the involvement of selected genes in detoxification pathways.

  4. Comparison of metal concentrations in Corbicula fluminea and Elliptio hopetonensis in the Altamaha River system, Georgia, USA.

    Science.gov (United States)

    Shoults-Wilson, W Aaron; Unrine, Jason M; Rickard, James; Black, Marsha C

    2010-09-01

    The present study evaluated the use of the invasive clam Corbicula fluminea as a surrogate for metal accumulation in native mussels. The tissue concentrations of As, Cd, Cu, Hg, Mn, Ni, Pb, and Zn were analyzed in Corbicula and a native Unionid mussel species (Elliptio hopetonensis) collected from 13 sites in the Altamaha River system (GA, USA). Corbicula accumulated greater concentrations of As, Cd, Cu, Hg, and Ni when compared to E. hopetonensis at the same sites. The reverse was true for the metals Mn and Zn, with E. hopetonensis accumulating greater concentrations than Corbicula. Concentrations of As, Cd, Cu, Hg, and Pb were found to be significantly (alpha = 0.05) positively correlated between the two species. Greater water alkalinity and hardness tended to negatively correlate with metal accumulation, while organism size tended to correlate positively with tissue concentrations. Tissue Cd, Cu, and Pb concentrations demonstrated a correlation between bivalve tissues and concentrations of those metals in fine sediments. These correlations were significant (alpha = 0.05) for Cd and Cu concentrations in Corbicula and Pb concentrations in E. hopetonensis. The present findings support the hypothesis that bioaccumulation of some metals by Corbicula can be used to approximate levels accumulated by co-occurring native mussel species. Copyright 2010 SETAC.

  5. Characterization of Selenium Species in the Shijimi Clam.

    Science.gov (United States)

    Yoshida, Sakura; Koga, Kaori; Iwataka, Miho; Fuchigami, Takeshi; Haratake, Mamoru; Nakayama, Morio

    2017-01-01

    Selenium is an essential trace element for humans and animals. Fish and shellfish are known to be rich in selenium and suppose to be an effective selenium source. In this study, we characterized the selenium species in the Shijimi clam (Corbicula japonica), which is a typical clam eaten in Japan. The Shijimi clam contains a relatively high concentration of selenium (3.5 µg-selenium/g-dry Shijimi). Approximately 30% of the total selenium in the Shijimi clam meat was extractable with water, while selenium in the Shijimi clam was hardly extracted with ethanol, chloroform and hexane. Based on an ultrafiltration study, the molecular mass of the major selenium species in the Shijimi water-extract was estimated to be less than 5000. Because amphoteric selenium species were contained in the Shijimi water-extract, which was indicated by ion-exchange chromatographic separation, an ion-pair reagent was utilized to extract the ionic selenium species into an organic solvent. A matrix assisted laser desorption ionization (MALDI) time of flight (TOF)-mass spectrometric analysis revealed the selenium isotopic pattern involving one selenium atom in a molecule with the 80Se molecular ion peak at m/z 534. This selenium species was mainly found in the visceral part of the Shijimi clam by imaging mass spectrometry.

  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. 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.

  8. Oxidative stress and histological changes following exposure to diamond nanoparticles in the freshwater Asian clam Corbicula fluminea (Müller, 1774).

    Science.gov (United States)

    Cid, Antonio; Picado, Ana; Correia, José Brito; Chaves, Rúben; Silva, Héber; Caldeira, Jorge; de Matos, António P Alves; Diniz, Mário S

    2015-03-02

    Recently, the scientific community became aware of the potential ability of nanoparticles to cause toxicity in living organisms. Therefore, many of the implications for aquatic ecosystems and its effects on living organisms are still to be evaluated and fully understood. In this study, the toxicity of nanodiamonds (NDs) was assessed in the freshwater bivalve (Corbicula fluminea) following exposure to different nominal concentrations of NDs (0.01, 0.1, 1, and 10 mg l(-1)) throughout 14 days. The NDs were characterized (gravimetry, pH, zeta potential, electron microscopy, and atomic force microscopy) confirming manufacturer information and showing NDs with a size of 4-6 nm. Oxidative stress enzymes activities (glutathione-S-transferase, catalase) and lipid peroxidation were determined. The results show a trend to increase in GST activities after seven days of exposure in bivalves exposed to NDs concentrations (>0.1 mg l(-1)), while for catalase a significant increase was found in bivalves exposed from 0.01 to 1.0 mg l(-1) following an exposure of 14 days. The histological analysis revealed alterations in digestive gland cells, such as vacuolization and thickening. The lipid peroxidation showed a trend to increase for the different tested NDs concentrations which is compatible with the observed cellular damage. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. 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.

  10. Oxidative stress and histological changes following exposure to diamond nanoparticles in the freshwater Asian clam Corbicula fluminea (Müller, 1774)

    Energy Technology Data Exchange (ETDEWEB)

    Cid, Antonio [REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnología, Centro de Química Fina e Biotecnología, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Picado, Ana; Correia, José Brito [LNEG-Laboratório Nacional de Energia e Geologia, I.P. Estrada do Paço do Lumiar 22, 1649-038 Lisboa (Portugal); Chaves, Rúben; Silva, Héber [Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz, 2825-511 Caparica (Portugal); Caldeira, Jorge [REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnología, Centro de Química Fina e Biotecnología, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz, 2825-511 Caparica (Portugal); Alves de Matos, António P. [Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz, 2825-511 Caparica (Portugal); Centro de Estudos do Ambiente e do Mar (CESAM/FCUL)—Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa (Portugal); and others

    2015-03-02

    Highlights: • We assess the toxicity of NDs in the bivalve Corbiculafluminea. • Exposure to NDs cause a stress oxidative response. • Stress oxidative enzymes increase following exposure to nanodiamonds. • Increase in lipid peroxidation suggests damage in cells membranes. • Histopathology reveals alterations in digestive gland cells. - Abstract: Recently, the scientific community became aware of the potential ability of nanoparticles to cause toxicity in living organisms. Therefore, many of the implications for aquatic ecosystems and its effects on living organisms are still to be evaluated and fully understood. In this study, the toxicity of nanodiamonds (NDs) was assessed in the freshwater bivalve (Corbicula fluminea) following exposure to different nominal concentrations of NDs (0.01, 0.1, 1, and 10 mg l{sup −1}) throughout 14 days. The NDs were characterized (gravimetry, pH, zeta potential, electron microscopy, and atomic force microscopy) confirming manufacturer information and showing NDs with a size of 4–6 nm. Oxidative stress enzymes activities (glutathione-S-transferase, catalase) and lipid peroxidation were determined. The results show a trend to increase in GST activities after seven days of exposure in bivalves exposed to NDs concentrations (>0.1 mg l{sup −1}), while for catalase a significant increase was found in bivalves exposed from 0.01 to 1.0 mg l{sup −1} following an exposure of 14 days. The histological analysis revealed alterations in digestive gland cells, such as vacuolization and thickening. The lipid peroxidation showed a trend to increase for the different tested NDs concentrations which is compatible with the observed cellular damage.

  11. 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

  12. Physico-chemical analysis of fish pond water in Okada and its ...

    African Journals Online (AJOL)

    ONOS

    2010-09-06

    Sep 6, 2010 ... Low dissolved oxygen levels reduce anti- predator behaviours of the fresh water Clam Corbicula fluminea. Fresh Water Biol. 50: 1233-1238. Stone NM, Thormforde HK (2003). Understanding your fish pond water analysis report. University of Arkansas Co-operative Extension. Printing services. pp. 1-4.

  13. Geographic distribution of mercury in asiatic clams, Corbicuia plumihea, from the North Fork Holston River, Virginia

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A study was conducted quantifying mercury concentrations in the Asiatic clam, Corbicula fluminea, from the North Fork Holston River, Virginia. The purpose of this...

  14. 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

    2017-11-28

    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.

  15. Experimental research on the impact of Corbicula fluminea on DIN exchange at a tidal flat sediment-water interface

    Science.gov (United States)

    Liu, Jie; Chen, Zhenlou; Xu, Shiyuan; Zheng, Xiangmin

    2007-10-01

    Based on a simulative experiment and a comparison analysis, the effect of bivalve Corbicula fluminea activity on sediment-water exchange of dissolved inorganic nitrogen (DIN) is studied. The areas included three intertidal flat sites of the Changjiang (Yangtze) River estuary in China. The interface exchange flux of ammonium, nitrate and nitrite in the short experiment (6 h) was -46.4-40, -74.8-929.1 and 2.5-14.6 µmol/(m2·h), respectively. It was found that the burrowing activities of C. fluminea increased NH{4/+} and NO{3/-} release from sediments to overlying water in the short-term experiment. During long-term incubation, NH{4/+} and NO{3/-} released in turn from the sediments. At the beginning of incubation, bioturbation by C. fluminea could accelerate NH{4/+} release from sediments 2-17 times in different sites, resulting in stronger nitrification and increased NO{3/-} concentrations in the overlying water. Sediment profile analysis post-incubation shows that organic matter mineralization and sediment-water NH{4/+} exchange had been stimulated by C. fluminea bioturbation and bioirrigation during the experiment. Therefore, C. fluminea activities such as excretion, burrowing, irrigation and turbation can effectively alter nitrogen dynamics and accelerate and stimulate nitrogen exchange and cycling at the sediment-water interface.

  16. 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

  17. Assessment of metal contamination, bioavailability, toxicity and bioaccumulation in extreme metallic environments (Iberian Pyrite Belt) using Corbicula fluminea.

    Science.gov (United States)

    Bonnail, E; Sarmiento, A M; DelValls, T A; Nieto, J M; Riba, I

    2016-02-15

    The Iberian Pyrite Belt (SW Iberian Peninsula) has intense mining activity. Currently, its fluvial networks receive extremely acid lixiviate residue discharges that are rich in sulphates and metals in solution (acid mine drainage, AMD) from abandoned mines. In the current study, the sediment and water quality were analysed in three different areas of the Odiel River to assess the risk associated with the metal content and its speciation and bioavailability. Furthermore, sediment contact bioassays were performed using the freshwater clam Corbicula fluminea to determine its adequacy as a biomonitoring tool in relation to theoretical risk indexes and regulatory thresholds. Reburial activity and mortality were used as the toxic responses of clams when exposed to contaminated sediment. The results showed coherence between the water and sediment chemical contamination for most of the metals. The reburial activity was correlated with the metal toxicity, but no clam mortality was registered. The bioaccumulation of the studied metals in the clam did not have a significant correlation with the bioavailable fraction of the metal content in the environment, which could be related to a potential different speciation in this singular environment. The bioaccumulation responses were negative for As, Cd and Zn in highly contaminated environments and were characterized as severe, considerable and low potential environmental risks, respectively. The results show that C. fluminea is a good biomonitor of Cu and Pb. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Viewpoint – Happy Like a Clam in French Water

    Directory of Open Access Journals (Sweden)

    Pierre-Frédéric Ténière-Buchot

    2013-06-01

    Full Text Available After a few lines about his personal history, the author presents the legal context for water in France in the last century, and describes the hesitant first steps of the French Agences de l’Eau during the 1970s. While the financial system of French water policy is presented in detail, the role of economic transfers between various categories of water users is underlined. Then, the general socio-political aspects of French water governance are explained. A diagram illustrating the financial decision-making procedure for water (the 'water wheel' is given. Simple advice is drawn from the experience of a CEO of a water agency: the most useful skill for a water professional is to know how to swim…

  19. Multiple Biomarker Responses in Corbicula fluminea Exposed to Copper in Laboratory Toxicity Tests.

    Science.gov (United States)

    Bonnail, Estefanía; Buruaem, Lucas M; Araujo, Giuliana S; Abessa, Denis M S; DelValls, T Ángel

    2016-08-01

    This study evaluated the alteration of the enzymatic system of the freshwater Asian clam exposed to different copper concentrations. Individuals of Corbicula fluminea were exposed to different concentrations of dissolved Cu (0.5, 1, and 2 mg L(-1)) for 7 days, then, biomarkers of oxidative stress (GST, GPx, GR), exposure (MTs), effect (AChE), and damage (LPO, DNA strand breaks) were quantified. Results showed positive correlations between dissolved metal concentrations and GPx, MTs, and DNA damage, and negative correlation with GST and AChE. In contrast, no clear trend was found for GR and LPO. In general, the established mechanisms of protection might have a beneficial effect on the decreasing ROS attack on membrane and the activation of the metallothioneins. Integrated biomarker analysis revealed that the measured alterations are well correlated with the levels of increasing dissolved copper concentrations in water, demonstrating the effectiveness of this organism for biomonitoring approach purposes.

  20. Bioavailability and oxidative stress of cadmium to Corbicula fluminea.

    Science.gov (United States)

    Ren, Jinghua; Luo, Jun; Ma, Hongrui; Wang, Xiaorong; Ma, Lena Q

    2013-04-01

    This work set out to study the effects of cadmium (Cd) in sediments on the antioxidant enzyme activities in the digestive gland of Asian clam Corbicula fluminea and to explore the potential for applying these responses to evaluate the Cd-contaminated sediment. Additionally, diffusive gradients in thin-films (DGT) technique was used to predict the response of its antioxidant defense system. The sediments, collected from Taihu Lake, were spiked with Cd at different concentrations (0.72, 0.91, 1.62, 2.59, 11.2, 20.4 and 40.6 mg kg(-1), dry weight). Asian clam was cultivated for 28 days. Concentrations of Cd in the body of Asian clam had a good relationship with concentrations of Cd in overlying water and sediments, as measured by DGT. Cd affected these biochemical parameters significantly, especially for superoxide (SOD), peroxidase (POD) and glutathione (GSH), which began to show higher sensitivity and have a significant difference in low dosage (0.91 mg Cd kg(-1)) compared with blank. Contents of MDA and MT, which were induced by Cd, increased with the increasing Cd concentration in sediments and reached peak values at 11.2 and 20.4 mg kg(-1), respectively, after 28 days exposure. All of these results suggested that biochemical responses cooperated in detoxifying and maintaining cellular metabolic homeostasis. The R(2) of regression analysis between the contents of MT and the concentrations of Cd measured by DGT, in sediments and soft body were 0.71, 0.94 and 0.88 after 28 days exposure. This suggested that DGT measurement could predict the response of MT. Cd accumulation, GSH and MT were indispensable biomarkers and the MDA content and DGT appeared to be promising biomarkers. The results clearly indicated that Cd could induce oxidative stress in the digestive gland of Asian clam. The combination of biomonitors with DGT can obtain different information about Cd bioavailability and confirm the significance of applying a suite of biomarkers rather than a selective

  1. The impact of paracetamol on selected biomarkers of the mollusc species Corbicula fluminea.

    Science.gov (United States)

    Brandão, Fátima Pinto; Pereira, Joana Luísa; Gonçalves, Fernando; Nunes, Bruno

    2014-01-01

    The Asian clam Corbicula fluminea is an invasive bivalve that has recently spread in Europe and currently represents a large portion of the aquatic biomass in specific areas. Because of the impacts that the species may have in invaded ecosystems, increased knowledge on the physiologic features of the species life-cycle under different environmental scenarios (e.g., contamination events) is critical to understand the dynamics of the invasion and resulting ecosystem imbalance. The presence of pharmaceutical residues in the aquatic environment has recently received great attention since high levels of contamination have been found, not only in sewage treatment plant effluents, but also in open waters. The present article reports toxicological biochemical effects of paracetamol to Corbicula fluminea following short- and long-term exposures. Oxidative stress parameters were specially focused namely catalase (CAT), glutathione S-transferases (GSTs), and glutathione reductase (GRed). The effect of tested substances on lipid peroxidation was also investigated. Paracetamol did not induce alterations on CAT activity, caused a significant decrease of GSTs activity following short- and long-term exposure (LOEC values of 532.78 mg L(-1) and 30.98 μg L(-1) , respectively), and was responsible for a significant and dose-dependent decrease of GRed activity in short- and long-term exposures. These results indicate that exposure to paracetamol can provoke significant alterations on the cellular redox status of C. fluminea. Copyright © 2011 Wiley Periodicals, Inc.

  2. Bioavailability and toxicity of metals from a contaminated sediment by acid mine drainage: linking exposure-response relationships of the freshwater bivalve Corbicula fluminea to contaminated sediment.

    Science.gov (United States)

    Sarmiento, Aguasanta M; Bonnail, Estefanía; Nieto, José Miguel; DelValls, Ángel

    2016-11-01

    Streams and rivers strongly affected by acid mine drainage (AMD) have legal vacuum in terms of assessing the water toxicity, since the use of conventional environmental quality biomarkers is not possible due to the absence of macroinvertebrate organisms. The Asian clam Corbicula fluminea has been widely used as a biomonitor of metal contamination by AMD in freshwater systems. However, these clams are considered an invasive species in Spain and the transplantation in the field study is not allowed by the Environmental Protection Agency. To evaluate the use of the freshwater bivalve C. fluminea as a potential biomonitor for sediments contaminated by AMD, the metal bioavailability and toxicity were investigated in laboratory by exposure of clams to polluted sediments for 14 days. The studied sediments were classified as slightly contaminated with As, Cr, and Ni; moderately contaminated with Co; considerably contaminated with Pb; and heavily contaminated with Cd, Zn, and specially Cu, being reported as very toxic to Microtox. On the fourth day of the exposure, the clams exhibited an increase in concentration of Ga, Ba, Sb, and Bi (more than 100 %), followed by Co, Ni, and Pb (more than 60 %). After the fourth day, a decrease in concentration was observed for almost all metals studied except Ni. An allometric function was used to determine the relationship between the increases in metal concentration in soft tissue and the increasing bioavailable metal concentrations in sediments.

  3. Investigations of water bounded in clam mussels (Mytilius edulis) by nuclear magnetic relaxation for protons; Badanie wody zwiazanej w muszlach omulka (Mytillus edulls) metoda magnetycznej relaksacji dla protonow

    Energy Technology Data Exchange (ETDEWEB)

    Haranczyk, H.; Niziol, J. [Inst. Fizyki, Uniwersytet Jagiellonski, Cracow (Poland); Falniowski, A. [Inst. Zoologii, Uniwersytet Jagiellonski, Cracow (Poland)

    1994-12-31

    The process of water bounding in clam shells has been investigated by nuclear magnetic relaxation of protons measurements. Decomposition of measured relaxation functions have been done using the specially constructed computer program. 4 refs, 4 figs, 3 tabs.

  4. Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water

    Energy Technology Data Exchange (ETDEWEB)

    Merschel, Gila, E-mail: g.merschel@jacobs-university.de; Bau, Michael

    2015-11-15

    High-technology metals — such as the rare earth elements (REE) — have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. - Highlights: • Corbicula fluminea shells are bioarchives of dissolved geogenic REE in

  5. NA{sup +}, K{sup +}-ATPase, histopathological, and genetic responses of Corbicula fluminea to sediment-associated copper

    Energy Technology Data Exchange (ETDEWEB)

    Brown, S. [Univ. of Mississippi, Oxford, MS (United States)

    1995-12-31

    Time-dependent responses to sediment-associated copper were studies at hierarchical levels of biological organization along an extreme concentration gradient (40 to 40,000 mg/kg total Cu). Laboratory and in situ estimates of molecular to tissue-level responses (Na/K-ATPase activity, DNA content, histopathology) were monitored in Corbicula fluminea (Asiatic clam), and compared with laboratory and field based survival of Corbicula and Elimia teres (an indigenous Gastropoda). Mollusc survival was, in turn, compared with effects on macrobenthic community composition along the stream/[Cu] gradient. Relationships between selected sediment characteristics and the bioavailability and toxicity of sediment associated copper were also investigated. Sediment-associated copper depressed Na/K-ATPase activity and led to histopathological damage of renal and gill epithelia (vacuolization, degeneration), indicating that impaired ion regulation was an important mechanism of toxicity. Concurrent reductions in DNA content were believed to be secondary effects due to cell death, not an indication of genotoxicity. Sublethal responses were significantly correlated with survival in both species; however, while survival in situ was indicative of differences in community structure, laboratory-based survival was not. Copper levels in tissues were indicative of exposure, but were not significantly correlated with adverse effects. Copper levels in sediments, interstitial water, and overlying water varied independently of sediment characteristics except pH. Cu/AVS ratios were predictive of Corbicula and Elimia survival, but were not significantly related to differences in community structure. Instead, macrobenthic community structure was influenced by other sediment factors (grain size, Eh, pH).

  6. Allochthonous Organic Matter Subsidize the High Secondary Production of the Invasive Bivalve Corbicula fluminea in Minho Estuary (N-Portugal)

    Science.gov (United States)

    The Asian clam Corbicula fluminea is one of the most invasive species in freshwater ecosystems. In Minho estuary, this species colonize all the middle and upper part of the estuary, dominating the abundance, biomass and secondary production in River Minho tidal freshwater area (T...

  7. When gourmet is not enough: Organic matter sources supporting the production of Corbicula fluminea in an invaded estuary

    Science.gov (United States)

    The Asian clam Corbicula fluminea is one of the most pervasive species in freshwater ecosystems. Our objective was to characterize the food sources fuelling C. fluminea in the Minho river estuary (NW-Iberian Peninsula, Europe), an estuarine ecosystem in which C. fluminea presentl...

  8. First record of Corbicula fluminalis (Müller, 1774 in Lake Garda (Italy, living in sympatry with Corbicula fluminea (Müller, 1774

    Directory of Open Access Journals (Sweden)

    Cristina CAPPELLETTI

    2009-02-01

    Full Text Available The first record of Corbicula fluminalis (Müller, 1774 (Mollusca: Bivalvia: Veneroidea: Corbiculidae in Lake Garda (Italy is presented. This clam was observed in July 2008 along the lake shore, with a high number of shells; sampling of lake sediment revealed the presence of live specimens. C. fluminea (Müller, 1774 has already been recorded in Lake Garda since 2002. The need for further studies on the presence and the spread of the two clams and the biodiversity of the invertebrate community of the lake is underlined, in relation to recent records of other invasive species, such as Dikerogammarus villosus (Sowinsky, 1894.

  9. Biodynamic modeling of PCB uptake by Macoma balthica and Corbicula fluminea from sediment amended with activated carbon

    Science.gov (United States)

    McLeod, Pamela B.; Luoma, S.N.; Luthy, R.G.

    2008-01-01

    Activated carbon amendment was assessed in the laboratory as a remediation strategy for freshwater sediment contaminated with polychlorinated biphenyls (PCBs) from the Grasse River (near Massena, NY). Three end points were evaluated: aqueous equilibrium PCB concentration, uptake into semipermeable membrane devices (SPMDs), and 28-day bioaccumulation in the clam Corbicula fluminea. PCB uptake by water, SPMDs, and clams followed similar trends, with reductions increasing as a function of carbon dose. Average percent reductions in clam tissue PCBs were 67, 86, and 95% for activated carbon doses of 0.7, 1.3, and 2.5% dry wt, respectively. A biodynamic model that incorporates sediment geochemistry and dietary and aqueous uptake routes was found to agree well with observed uptake by C. fluminea in our laboratory test systems. Results from this study were compared to 28-day bioaccumulation experiments involving PCB-contaminated sediment from Hunters Point Naval Shipyard (San Francisco Bay, CA) and the clam Macoma balthica. Due to differences in feeding strategy, M. balthica deposit-feeds whereas C. fluminea filter-feeds, the relative importance of the aqueous uptake route is predicted to be much higher for C. fluminea than for M. balthica. Whereas M. balthica takes up approximately 90% of its body burden through sediment ingestion, C. fluminea only accumulates approximately 45% via this route. In both cases, results strongly suggest that it is the mass transfer of PCBs from native sediment to added carbon particles, not merely reductions in aqueous PCB concentrations, that effectively reduces PCB bioavailability and uptake by sediment-dwelling organisms. ?? 2008 American Chemical Society.

  10. Detection of genotoxicity of water from an urbanized stream, in Corbicula fluminea (Mollusca) (in vivo) and CHO-K1 cells (in vitro) using comet assay.

    Science.gov (United States)

    Rigonato, Janaina; Mantovani, Mário Sérgio; Jordão, Berenice Quinzani

    2010-07-01

    The comet assay was utilized to investigate the quality of water from seven locations along the Cambé Stream, in vivo (Corbicula fluminea hemolymph), in vitro (CHO-K1 cells), in situ, and in laboratory studies. The Cambé Stream basin (Londrina, PR, Brazil) is almost completely urbanized and receives different forms of industrial and domestic runoff. The data indicated the occurrence of DNA damage in cells examined in vivo and in vitro, shown by the significant increase in frequencies of cells with DNA damage after exposure to water from all seven locations used in the study. Our results strongly suggest the presence of genotoxic agent(s) in water at all of the sampled locations, demonstrated by elevated numbers of cells with DNA damaged in field and laboratory tests. In all of the places sampled, domestic sewage influence appeared to be one important cause for the introduction of xenobiotics, environmental genotoxins, and pollutants into the water. Thus, the comet assay applied in these cell systems was able to detect adverse environmental conditions, proving to be a very adequate short-term test and should be included in batteries of tests utilized in the monitoring of aquatic environments.

  11. Uptake of contaminants of emerging concern by the bivalves Anodonta californiensis and Corbicula fluminea.

    Science.gov (United States)

    Ismail, Niveen S; Müller, Claudia E; Morgan, Rachel R; Luthy, Richard G

    2014-08-19

    Uptake of seven contaminants regularly detected in surface waters and spanning a range of hydrophobicities (log D(ow) -1 to 5) was studied for two species of freshwater bivalves, the native mussel Anodonta californiensis and the invasive clam Corbicula fluminea. Batch systems were utilized to determine compound partitioning, and flow-through systems, comparable to environmental conditions in effluent dominated surface waters, were used to determine uptake and depuration kinetics. Uptake of compounds was independent of bivalve type. Log bioconcentration factor (BCF) values were correlated with log D(ow) for nonionized compounds with the highest BCF value obtained for triclocarban (TCC). TCC concentrations were reduced in the water column due to bivalve activity. Anionic compounds with low D(ow) values, i.e., clofibric acid and ibuprofen, were not removed from water, while the organic cation propranolol showed biouptake similar to that of TCC. Batch experiments supported compound uptake patterns observed in flow-through experiments. Contaminant removal from water was observed through accumulation in tissue or settling as excreted pseudofeces or feces. The outcomes of this study indicate the potential utility of bivalve augmentation to improve water quality by removing hydrophobic trace organic compounds found in natural systems.

  12. Experimental challenges of wild Manila clams with Perkinsus species isolated from naturally infected wild Manila clams.

    Science.gov (United States)

    Waki, Tsukasa; Shimokawa, Jun; Watanabe, Shinji; Yoshinaga, Tomoyoshi; Ogawa, Kazuo

    2012-09-15

    Manila clams, Ruditapes philippinarum, are widely harvested in the coastal waters in Japan. However, there have been significant decreases in the populations of Manila clams since the 1980s. It is thought that infection with the protozoan Perkinsus species has contributed to these decreases. A previous study demonstrated that high infection levels of a pure strain of Perkinsus olseni (ATCC PRA-181) were lethal to hatchery-raised small Manila clams, however, the pathogenicity of wild strain Perkinsus species to wild Manila clam is unclear. To address this, we challenged large (30-40 mm in shell length) and small (3-15 mm in shell length) wild Manila clams with Perkinsus species isolated from naturally infected wild Manila clams. We report high mortalities among the small clams, but not among the large ones. This is the first report to confirm the pathogenicity of wild isolate of Perkinsus species to wild Manila clams. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Corbicula fluminea (Bivalvia: Corbiculidae): a possible second molluscan intermediate host of Echinostoma cinetorchis (Trematoda: Echinostomatidae) in Korea

    Science.gov (United States)

    Jung, Younghun; Park, Yun-Kyu; Hwang, Myung-Gi; Soh, Chin-Thack

    2001-01-01

    More than 1,500 clams of Corbicula fluminea, the most favorable food source of freshwater bivalves in Korea, were collected from 5 localities to examine cercarial and metacercarial infection with Echinostoma cinetorchis. Although 3 clams infected with suspicious E. cinetorchis metacercariae out of 200 specimens collected at Kangjin, Chollanam-do were detected, no cercarial and metacercarial infections with E. cinetorchis were observed in field-collected Corbicula specimens. In the susceptibility experiments with laboratory-reared clams, those infected with miracidia of E. cinetorchis did not release their cercariae up to 60 days after infection. To confirm the identity of second intermediate host of E. cinetorchis experimentally, a total of 30 clams were exposed to the cercariae from Segmentina hemisphaerula that had been infected with miracidia of E. cinetorchis. The clams were susceptible to cercariae of E. cinetorchis with an infection rate of 93.3%. Metacercariae from clams taken more than 7 days after cercarial exposure were fed to rats (S/D strain), and adult worms of E. cinetorchis, characterized by 37-38 collar spines on the head crown, were recovered from the ileocecal regions. This is the first report of C. fluminea as a possible second intermediate host of E. cinetorchis. PMID:11775336

  14. How the fluctuations of water levels affect populations of invasive bivalve Corbicula fluminea (Müller, 1774) in a Neotropical reservoir?

    Science.gov (United States)

    Paschoal, L R P; Andrade, D P; Darrigran, G

    2015-01-01

    Corbicula fluminea is an invasive bivalve responsible for several environmental and financial problems around the globe. Despite the invasive potential of this species, it suffers certain restrictions in lentic environments due to natural phenomena that significantly affect its population structure (e.g. water column fluctuation and sunlight exposure). The present study addresses how temporal decline of the water level in a Neotropical reservoir and exposure to sunlight affect the population structure of C. fluminea. Samplings were carried out twice in the reservoir of Furnas Hydroelectric Power Station (HPS) (Minas Gerais, Brazil), in 2011 and 2012. Population density, spatial distribution and mean shell length of C. fluminea were estimated for each year after sampling in 51 quadrats (0.0625m2) placed on three transects at different distances along the reservoir margins (0, 10 and 20 m from a fixed-point). We observed a predominance of C. fluminea in both years, with a simultaneous gradual decrease in density and richness of native species in the sampling area. Significant differences in density of C. fluminea were registered at different distances from the margin, and are related to the temporal variability of physical conditions of the sediment and water in these environments. We also registered a trend toward an increase in the density and aggregation of C. fluminea as we moved away from the margin, due to the greater stability of these areas (>10 m). The mean shell length of C. fluminea showed significant difference between the distinct distances from the margin and during the years, as well as the interaction of these factors (Distances vs.Years). These results were associated with the reproductive and invasive capacity of this species. This study reveals that these temporal events (especially water column fluctuation) may cause alterations in density, spatial distribution and mean shell length of C. fluminea and the composition of the native malacofauna in

  15. How the fluctuations of water levels affect populations of invasive bivalve Corbicula fluminea (Müller, 1774 in a Neotropical reservoir?

    Directory of Open Access Journals (Sweden)

    LRP. Paschoal

    Full Text Available Corbicula fluminea is an invasive bivalve responsible for several environmental and financial problems around the globe. Despite the invasive potential of this species, it suffers certain restrictions in lentic environments due to natural phenomena that significantly affect its population structure (e.g. water column fluctuation and sunlight exposure. The present study addresses how temporal decline of the water level in a Neotropical reservoir and exposure to sunlight affect the population structure of C. fluminea. Samplings were carried out twice in the reservoir of Furnas Hydroelectric Power Station (HPS (Minas Gerais, Brazil, in 2011 and 2012. Population density, spatial distribution and mean shell length of C. fluminea were estimated for each year after sampling in 51 quadrats (0.0625m2 placed on three transects at different distances along the reservoir margins (0, 10 and 20 m from a fixed-point. We observed a predominance of C. fluminea in both years, with a simultaneous gradual decrease in density and richness of native species in the sampling area. Significant differences in density of C. fluminea were registered at different distances from the margin, and are related to the temporal variability of physical conditions of the sediment and water in these environments. We also registered a trend toward an increase in the density and aggregation of C. fluminea as we moved away from the margin, due to the greater stability of these areas (>10 m. The mean shell length of C. fluminea showed significant difference between the distinct distances from the margin and during the years, as well as the interaction of these factors (Distances vs.Years. These results were associated with the reproductive and invasive capacity of this species. This study reveals that these temporal events (especially water column fluctuation may cause alterations in density, spatial distribution and mean shell length of C. fluminea and the composition of the native

  16. Genetic analysis of the purplish Washington clam (Saxidomus purpuratus Sowerby) of Korean coastal waters.

    Science.gov (United States)

    Cho, Eun-Seob; Seo, Young-Il; Suh, Young-Sang

    2013-05-01

    To investigate the genetic structure of the purplish Washington clam population, Saxidomus purpuratus Sowerby, in Korea. A portion of mitochondrial COI gene sequences (605 bp) for phylogenetic comparison was determined. Sequence analysis of 62 individuals collected from six regions revealed 13 haplotypes. Phylogenetic analysis using Phylogeny Inference Package (PHYLIP) subdivided the purplish Washington clam into two clades (termed clade A and B), weak supported groups (Yeosu, Samcheonpo, Jubyeon and Geojedo, and the other at Sineju. Population genetic analysis subdivided these two population groups with a geographic distance (d = 0.431, p = 0.379). Furthermore, in the Sineju population, the maximum sequence divergence (2.67%) and minimum nucleotide diversity (0.0012426) were shown in which might be reflective of a relatively small population size and the geographical isolation of the population as compared with other populations. However, a very high migration rate (N(m) = 59.62-infinite) and a very low level of geographic distance (F(ST) = -0.076-0.055) were noted to exist among the South and East Sea populations, suggesting that individuals between populations should show a significantly active genetic mixing and migration regardless of geography. These findings allowed us to conclude that the purplish Washington clam populations occurring in the South and East Sea were formed with randomly dispersed individuals.

  17. Accumulation and Growth Responses in Corbicula fluminea Along a Longitudinal Gradient of Metal Exposure

    Science.gov (United States)

    Peltier, G. L.; Wright, M. S.; Hopkins, W. A.; Meyer, J. L.

    2005-05-01

    In a previous study, we investigated the concentrations of arsenic, selenium, cadmium, and mercury associated with different land uses in a large river system using an indicator species Corbicula fluminea (Asiatic clam). We found that Corbicula fluminea collected from sites downstream of discharges from coal-fired power plants (CFPP) had significantly higher tissue concentrations of selenium and cadmium than all other land use types. In order to quantify the bioavailability of metals associated with CFPP discharges in a lotic system, we designed a three month experiment in which clams were deployed in cages at four sites along a 3.5 km reach of stream at the Savannah River Site. We assessed metal accumulation in the clam tissue and shell growth over the entire reach. After 84 days, clams at the upstream, most contaminated site had the highest growth rate and highest mean concentrations of arsenic (7.85 ppm), selenium (17.05 ppm), and cadmium (7.28 ppm). Tissue concentrations decreased rapidly over the first 400 m rather than gradually along the entire reach.

  18. Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water.

    Science.gov (United States)

    Merschel, Gila; Bau, Michael

    2015-11-15

    High-technology metals - such as the rare earth elements (REE) - have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Heavy metal determinations in algae, mussels and clams. Their possible employment for assessing the sea water quality criteria

    Science.gov (United States)

    Locatelli, C.

    2003-05-01

    An empirical criterion for a possible classification of sea water quality is proposed. It is based on the knowledge of metal content in algae (Ulva Rigida) mussels (Mytilus Galloprovincialis) and clams (Tapes Philippinarum), three species present in marine ecosystems. The elements considered are Hg, Cu, Pb, Cd, Zn, Ni and Cr. The anatytical technique employed is Atomic Absorption Spectroscopy (AAS). The analytical procedure has been verified on three standard reference materials : Sea Water BCR-CRM 403, Ulva Lactuca BCR-CRM 279 and Mussel Tissue BCR-CRM 278. For all the elements, in addition to detection limits, accuracy and precision are given : the former, expressed as retative error (e). and the latter, expressed as relative standard deviation (sr), were in all cases lower than 6%.

  20. Heavy metal determinations in algae and clams and their possible employment for assessing the sea water quality criteria.

    Science.gov (United States)

    Locatelli, C; Fabbri, D; Torsi, G

    2001-01-01

    An empirical criterion for a possible classification of sea water quality is proposed. It is based on the knowledge of metal content in algae (Ulva Rigida) and clams (Tapes Philippinarum), two species present in marine ecosystems. The elements considered are Hg, Cu, Pb, Cd, Zn. The analytical technique employed is Differential Pulse Anodic Stripping Voltammetry (DPASV) in the case of Cu, Pb, Cd, Zn, while the determination of mercury is obtained by the Cold Vapour Atomic Absorption Spectroscopy (CV-AAS) technique with SnCl2 as reducing agent. The analytical procedure has been verified on three standard reference materials: Sea Water BCR-CRM 403, Ulva Lactuca BCR-CRM 279 and Mussel Tissue BCR-CRM 278. For all the elements, in addition to detection limits, accuracy and precision are given: the former, expressed as relative error (e), and the latter, expressed as relative standard deviation (Sr), were in all cases lower than 6%.

  1. The unusual mineral vaterite in shells of the freshwater bivalve Corbicula fluminea from the UK

    Science.gov (United States)

    Spann, Nicole; Harper, Elizabeth M.; Aldridge, David C.

    2010-08-01

    Asian clams ( Corbicula fluminea) with abnormally thickened shell valves were found in four rivers in the UK (Rivers Yare, Waveney, Thames and New Bedford River). The material making up these malformations was the rare calcium carbonate polymorph vaterite. Vaterite is seldom found in the natural environment because it is less stable than the other calcium carbonate polymorphs (aragonite and calcite). In the few reported cases of vaterite formation in molluscs, it is usually related to unusual biomineralisation events such as shell regeneration, pearls and initial stages of shell formation. We compared two populations from the Rivers Yare and Waveney in the Norfolk Broads, UK, one (River Waveney) displaying dominantly the normal Corbicula shell form with aragonitic shells. In the River Yare population, all individuals sampled had shell deformations to different extents. These deformations were apparent as bulges on the inside of the ventral shell margin. X-ray diffraction confirmed that the shell material in the bulges of recently collected clams was vaterite. Other parts of the deformed shells were aragonitic. The shell deformations alter the shell morphology, leading to higher and wider shells. The shell microstructure is fibrous in the vateritic parts and crossed-lamellar in the aragonitic parts of deformed or non-deformed shells. The cause for the malformations is probably a disrupted biomineralisation process in the bivalves. Fossil Corbicula specimens from the late Pleistocene had similar deformations, suggesting that this is not a response to anthropogenic causes, such as pollution.

  2. 33 CFR 117.323 - Outer Clam Bay

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Outer Clam Bay 117.323 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.323 Outer Clam Bay The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on signal if at least 30 minutes advance notice is given. ...

  3. Effect of acidic electrolyzed water-induced bacterial inhibition and injury in live clam (Venerupis philippinarum) and mussel (Mytilus edulis).

    Science.gov (United States)

    Al-Qadiri, Hamzah M; Al-Holy, Murad A; Shiroodi, Setareh Ghorban; Ovissipour, Mahmoudreza; Govindan, Byju N; Al-Alami, Nivin; Sablani, Shyam S; Rasco, Barbara

    2016-08-16

    The effect of acidic electrolyzed water (AEW) on inactivating Escherichia coli O104:H4, Listeria monocytogenes, Aeromonas hydrophila, Vibrio parahaemolyticus and Campylobacter jejuni in laboratory contaminated live clam (Venerupis philippinarum) and mussel (Mytilus edulis) was investigated. The initial levels of bacterial contamination were: in clam 4.9 to 5.7log10CFU/g, and in mussel 5.1 to 5.5log10CFU/g. Two types of AEW were used for treatment time intervals of 1 and 2h: strong (SAEW) with an available chlorine concentration (ACC) of 20mg/L, pH=3.1, and an oxidation-reduction potential (ORP) of 1150mV, and weak (WAEW) at ACC of 10mg/L, pH=3.55 and ORP of 950mV. SAEW and WAEW exhibited significant inhibitory activity against inoculated bacteria in both shellfish species with significant differences compared to saline solutions treatments (1-2% NaCl) and untreated controls (0h). SAEW showed the largest inhibitory activity, the extent of reduction (log10CFU/g) ranged from 1.4-1.7 for E. coli O104:H4; 1.0-1.6 for L. monocytogenes; 1.3-1.6 for A. hydrophila; 1.0-1.5 for V. parahaemolyticus; and 1.5-2.2 for C. jejuni in both types of shellfish. In comparison, significantly (Pmussel, which may help control possible unhygienic practices during production and processing of shellfish without apparent changes in the quality of the shellfish. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Water quality of the culture beds of hard clam and adjacent sea of the Yeosu Refinery of Honam Oil Refinery Company in Kwang Yang Bay

    Energy Technology Data Exchange (ETDEWEB)

    Won, J.H.; Go, N.P.

    1975-01-01

    The effects of oil spill from the wastewater of Yeosu Refinery on water quality of hard clam culture beds in Taein-Ri, Kwang Yang Bay, South Korea, were studied. Wastewater and oil spillage may reach culture beds in 6 to 8 h by tidal current movement. Water quality is nearly as normal as unpolluted sea water except the concentration of n-hexane extractive chemicals which was higher than unpolluted sea water in Sept.-Oct. 1973. It may be caused by wastewater of Yeosu Refinery.

  5. Propeleda platessa (Dall, 1890), a Nut Clam new for the coastal waters of Surinam (Pelecypoda, Nuculanidae)

    NARCIS (Netherlands)

    Nijssen-Meyer, J.

    1972-01-01

    A species of the family Nuculanidae, Propeleda platessa (Dall, 1890), from the coastal waters of Surinam is described and figured. It is compared with related species. The status of the genus Propeleda is discussed briefly.

  6. 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.

  7. Direct and indirect effects of different types of microplastics on freshwater prey (Corbicula fluminea) and their predator (Acipenser transmontanus)

    Science.gov (United States)

    Parnis, J. Mark; Browne, Mark A.; Serrato, Sebastian; Reiner, Eric J.; Robson, Matthew; Young, Thomas; Diamond, Miriam L.; Teh, Swee J.

    2017-01-01

    We examined whether environmentally relevant concentrations of different types of microplastics, with or without PCBs, directly affect freshwater prey and indirectly affect their predators. Asian clams (Corbicula fluminea) were exposed to environmentally relevant concentrations of polyethylene terephthalate (PET), polyethylene, polyvinylchloride (PVC) or polystyrene with and without polychlorinated biphenyls (PCBs) for 28 days. Their predators, white sturgeon (Acipenser transmontanus), were exposed to clams from each treatment for 28 days. In both species, we examined bioaccumulation of PCBs and effects (i.e., immunohistochemistry, histology, behavior, condition, mortality) across several levels of biological organization. PCBs were not detected in prey or predator, and thus differences in bioaccumulation of PCBs among polymers and biomagnification in predators could not be measured. One of the main objectives of this study was to test the hypothesis that bioaccumulation of PCBs would differ among polymer types. Because we could not answer this question experimentally, a bioaccumulation model was run and predicted that concentrations of PCBs in clams exposed to polyethylene and polystyrene would be greater than PET and PVC. Observed effects, although subtle, seemed to be due to microplastics rather than PCBs alone. For example, histopathology showed tubular dilation in clams exposed to microplastics with PCBs, with only mild effects in clams exposed to PCBs alone. PMID:29108004

  8. Using trace element concentrations in Corbicula fluminea to identify potential sources of contamination in an urban river

    Energy Technology Data Exchange (ETDEWEB)

    Loeffler Peltier, Gretchen [University of Georgia, Institute of Ecology, Athens, GA 30602 (United States)], E-mail: gl232@columbia.edu; Meyer, Judith L. [University of Georgia, Institute of Ecology, Athens, GA 30602 (United States); Jagoe, Charles H.; Hopkins, William A. [University of Georgia, Savannah River Ecology Laboratory, Aiken, SC 29802 (United States)

    2008-07-15

    We used the biomonitor, Corbicula fluminea, to investigate the contributions of trace elements associated with different point sources and land uses in a large river. Trace elements were analyzed in tissues of clams collected from 15 tributary streams draining five land use or point source types: agriculture, forest, urban, coal-fired power plant (CFPP), and wastewater (WWTP). Clams from forested catchments had elevated Hg concentrations, and concentrations of arsenic and selenium were highest (5.0 {+-} 0.2 and 13.6 {+-} 0.9 {mu}g g{sup -1} dry mass (DM), respectively) in clams from CFPP sites. Cadmium concentrations were significantly higher in clams from urban and CFPP sites (4.1 {+-} 0.2 and 3.6 {+-} 0.9 {mu}g g{sup -1} DM, respectively). Non-metric multidimensional scaling (NMS) of tissue concentrations in clams clustered at CFPP and forest/agriculture sites at opposite ends of the ordination space, and the distribution of sites was driven by Cu, Zn, Cd, and Hg. - C. fluminea collected downstream of CFPPs had elevated tissue concentrations of trace elements.

  9. Direct and indirect effects of different types of microplastics on freshwater prey (Corbicula fluminea and their predator (Acipenser transmontanus.

    Directory of Open Access Journals (Sweden)

    Chelsea M Rochman

    Full Text Available We examined whether environmentally relevant concentrations of different types of microplastics, with or without PCBs, directly affect freshwater prey and indirectly affect their predators. Asian clams (Corbicula fluminea were exposed to environmentally relevant concentrations of polyethylene terephthalate (PET, polyethylene, polyvinylchloride (PVC or polystyrene with and without polychlorinated biphenyls (PCBs for 28 days. Their predators, white sturgeon (Acipenser transmontanus, were exposed to clams from each treatment for 28 days. In both species, we examined bioaccumulation of PCBs and effects (i.e., immunohistochemistry, histology, behavior, condition, mortality across several levels of biological organization. PCBs were not detected in prey or predator, and thus differences in bioaccumulation of PCBs among polymers and biomagnification in predators could not be measured. One of the main objectives of this study was to test the hypothesis that bioaccumulation of PCBs would differ among polymer types. Because we could not answer this question experimentally, a bioaccumulation model was run and predicted that concentrations of PCBs in clams exposed to polyethylene and polystyrene would be greater than PET and PVC. Observed effects, although subtle, seemed to be due to microplastics rather than PCBs alone. For example, histopathology showed tubular dilation in clams exposed to microplastics with PCBs, with only mild effects in clams exposed to PCBs alone.

  10. Direct and indirect effects of different types of microplastics on freshwater prey (Corbicula fluminea) and their predator (Acipenser transmontanus).

    Science.gov (United States)

    Rochman, Chelsea M; Parnis, J Mark; Browne, Mark A; Serrato, Sebastian; Reiner, Eric J; Robson, Matthew; Young, Thomas; Diamond, Miriam L; Teh, Swee J

    2017-01-01

    We examined whether environmentally relevant concentrations of different types of microplastics, with or without PCBs, directly affect freshwater prey and indirectly affect their predators. Asian clams (Corbicula fluminea) were exposed to environmentally relevant concentrations of polyethylene terephthalate (PET), polyethylene, polyvinylchloride (PVC) or polystyrene with and without polychlorinated biphenyls (PCBs) for 28 days. Their predators, white sturgeon (Acipenser transmontanus), were exposed to clams from each treatment for 28 days. In both species, we examined bioaccumulation of PCBs and effects (i.e., immunohistochemistry, histology, behavior, condition, mortality) across several levels of biological organization. PCBs were not detected in prey or predator, and thus differences in bioaccumulation of PCBs among polymers and biomagnification in predators could not be measured. One of the main objectives of this study was to test the hypothesis that bioaccumulation of PCBs would differ among polymer types. Because we could not answer this question experimentally, a bioaccumulation model was run and predicted that concentrations of PCBs in clams exposed to polyethylene and polystyrene would be greater than PET and PVC. Observed effects, although subtle, seemed to be due to microplastics rather than PCBs alone. For example, histopathology showed tubular dilation in clams exposed to microplastics with PCBs, with only mild effects in clams exposed to PCBs alone.

  11. Using trace element concentrations in Corbicula fluminea to identify potential sources of contamination in an urban river

    Energy Technology Data Exchange (ETDEWEB)

    Peltier, G.L.; Meyer, J.L.; Jagoe, C.H.; Hopkins, W.A. [University of Georgia, Athens, GA (United States)

    2008-07-15

    We used the biomonitor, Corbicula fluminea, to investigate the contributions of trace elements associated with different point sources and land uses in a large river. Trace elements were analyzed in tissues of clams collected from 15 tributary streams draining five land use or point source types: agriculture, forest, urban, coal-fired power plant (CFPP), and wastewater (WWTP). Clams from forested catchments had elevated Hg concentrations, and concentrations of arsenic and selenium were highest (5.0 {+-} 0.2 and 13.6 {+-} 0.9 {mu}g{sup -1} dry mass (DM), respectively) in clams from CFPP sites. Cadmium concentrations were significantly higher in clams from urban and CFPP sites (4.1 {+-} 0.2 and 3.6 {+-} 0.9 {mu}g{sup -1} DM, respectively). Non-metric multidimensional scaling (NMS) of tissue concentrations in clams clustered at CFPP and forest/agriculture sites at opposite ends of the ordination space, and the distribution of sites was driven by Cu, Zn, Cd, and Hg.

  12. Acetylcholinesterase activity in Corbicula fluminea Mull., as a biomarker of organophosphate pesticide pollution in Pinacanauan River, Philippines.

    Science.gov (United States)

    Beltran, Kimberly S; Pocsidio, Glorina N

    2010-06-01

    Organophosphates are known to inhibit the enzyme acetylcholinesterase. In this study, the AChE activity from the total soft tissues of Corbicula fluminea Mull. was used as a biomarker of organophosphate pollution in Pinacanauan River. Clams were collected from two different sites and at different seasons of the year. A colorimetric assay on the total soft tissues of the clams showed a directly proportional relationship between enzyme activity and condition of the riverine system. In vitro experiments on the total soft tissue, adductor muscles, digestive glands, and gills were conducted to assess the degree of localization of AChE as well as the sensitivity and tolerance of the enzymes in these tissues to varying concentrations of malathion. The degree of enzyme localization from highest to lowest is as follows: adductor muscle > gills > digestive gland whereas sensitivity to OP from greatest to least is: gills > adductor muscles > digestive gland.

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

    African Journals Online (AJOL)

    The Clam (Galatea paradoxa Born 1778) is a dermesal dweller of riverine water and filter feed by passing water through gut concentrating particulate matter ... Citrobacter, Enterobacter, Escherichia, Flavobacterium, Klebsiella, Mi-crococcus, Morganella, Proteus, Pseudomonas, Salmonella, Serratia, Staphylococcus, ...

  14. Antioxidant Effects of Short-Neck Clam (Tapes philippinarum) Water Extract Containing Taurine Against AAPH-Induced Oxidative Stress in Zebrafish Embryos.

    Science.gov (United States)

    Lee, Dong-Sung; Lee, Seung-Hong; Jeon, You-Jin; Cheong, Sun Hee

    2017-01-01

    The purpose of this study was to investigate the antioxidant activities of short-neck clam water extract (SNC-WE) enriched in taurine. In the present study, the half-maximal inhibitory concentration (IC50) values of the SNC-WE for DPPH, superoxide, and alkyl radical scavenging activities determined by an electron spin resonance (ESR) spectrometer were 3.16, 1.54 and 0.58 mg/mL, respectively. Furthermore, we evaluated the inhibitory effect of taurine enriched SNC-WE against the oxidative stress induced by 2,2'-azobis dihydrochloride (AAPH) in zebrafish embryos. In the present study, we observed that taurine enriched SNC-WE significantly suppressed reactive oxygen species (ROS) production, lipid peroxidation as well as cell death in the zebrafish model. These results indicate that taurine enriched SNC-WE might have antioxidant effects in both in vitro and in vivo zebrafish model.

  15. Accumulation of trace elements and growth responses in Corbicula fluminea downstream of a coal-fired power plant.

    Science.gov (United States)

    Peltier, Gretchen Loeffler; Wright, Meredith S; Hopkins, William A; Meyer, Judy L

    2009-07-01

    Lentic organisms exposed to coal-fired power plant (CFPP) discharges can have elevated trace element concentrations in their tissues, but this relationship and its potential consequences are unclear for lotic organisms. To explore these patterns in a lotic environment, we transplanted Corbicula fluminea from a reference stream to a stream receiving CFPP discharge. We assessed trace element accumulation and glutathione concentration in clam tissue, shell growth, and condition index at five sites along a contamination gradient. Clams at the most upstream and contaminated site had the highest growth rate, condition index, glutathione concentrations, and concentrations of arsenic (7.85+/-0.25 microg/g [dry mass]), selenium (17.75+/-0.80 microg/g), and cadmium (7.28+/-0.34 microg/g). Mercury concentrations declined from 4.33+/-0.83 to 0.81+/-0.11 microg/g [dry mass] in clams transplanted into the selenium-rich environment nearest the power plant, but this effect was not as evident at less impacted, downstream sites. Even though dilution of trace elements within modest distances from the power plant reduced bioaccumulation potential in clams, long-term loading of trace elements to downstream depositional regions (e.g., slow moving, silty areas) is likely significant.

  16. Accumulation of trace elements and growth responses in Corbicula fluminea downstream of a coal-fired power plant

    Energy Technology Data Exchange (ETDEWEB)

    Peltier, G.L.; Wright, M.S.; Hopkins, W.A.; Meyer, J.L. [University of Georgia, Athens, GA (United States)

    2009-07-15

    Lentic organisms exposed to coal-fired power plant (CFPP) discharges can have elevated trace element concentrations in their tissues, but this relationship and its potential consequences are unclear for lotic organisms. To explore these patterns in a lotic environment, we transplanted Corbicula fluminea from a reference stream to a stream receiving CFPP discharge. We assessed trace element accumulation and glutathione concentration in clam tissue, shell growth, and condition index at five sites along a contamination gradient. Clams at the most upstream and contaminated site had the highest growth rate, condition index, glutathione concentrations, and concentrations of arsenic (7.85 {+-} 0.25 {mu} g/g (dry mass)), selenium (17.75 {+-} 0.80 {mu} g/g), and cadmium (7.28 {+-} 0.34 {mu} g/g). Mercury concentrations declined from 4.33 {+-} 0.83 to 0.81 {+-} 0.11 {mu} g/g (dry mass) in clams transplanted into the selenium-rich environment nearest the power plant, but this effect was not as evident at less impacted, downstream sites. Even though dilution of trace elements within modest distances from the power plant reduced bioaccumulation potential in clams, long-term loading of trace elements to downstream depositional regions (e.g., slow moving, silty areas) is likely significant.

  17. The Control of an Invasive Bivalve, Corbicula fluminea, Using Gas Impermeable Benthic Barriers in a Large Natural Lake

    Science.gov (United States)

    Wittmann, Marion E.; Chandra, Sudeep; Reuter, John E.; Schladow, S. Geoffrey; Allen, Brant C.; Webb, Katie J.

    2012-06-01

    Anoxia can restrict species establishment in aquatic systems and the artificial promotion of these conditions can provide an effective control strategy for invasive molluscs. Low abundances (2-20 m-2) of the nonnative bivalve, Asian clam ( Corbicula fluminea), were first recorded in Lake Tahoe, CA-NV in 2002 and by 2010 nuisance-level population densities (>10,000 m-2) were observed. A non-chemical control method using gas impermeable benthic barriers to reduce dissolved oxygen (DO) concentrations available to C. fluminea was tested in this ultra-oligotrophic natural lake. In 2009, the impact of ethylene propylene diene monomer (EPDM) sheets (9 m2, n = 6) on C. fluminea beds was tested on 1-7 day intervals over a 56 day period (August-September). At an average water temperature of 18 °C, DO concentrations under these small barriers were reduced to zero after 72 h resulting in 100 % C. fluminea mortality after 28 days. In 2010, a large EPDM barrier (1,950 m2) was applied to C. fluminea populations for 120 days (July-November). C. fluminea abundances were reduced over 98 % after barrier removal, and remained significantly reduced (>90 %) 1 year later. Non-target benthic macroinvertebrate abundances were also reduced, with variable taxon-specific recolonization rates. High C. fluminea abundance under anoxic conditions increased the release of ammonium and soluble reactive phosphorus from the sediment substrate; but levels of unionized ammonia were low at 0.004-0.005 mg L-1. Prolonged exposure to anoxia using benthic barriers can provide an effective short term control strategy for C. fluminea.

  18. 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.

  19. Differential protein expression in Corbicula fluminea upon exposure to a Microcystis aeruginosa toxic strain.

    Science.gov (United States)

    Martins, José C; Leão, Pedro N; Vasconcelos, Vítor

    2009-03-15

    Changes in protein expression induced by a Microcystis aeruginosa toxic strain in the freshwater clam Corbicula fluminea were studied using a proteomic approach in an effort to identify new molecular biomarkers. Clams were fed with 1 x 10(6) cells mL(-1) of a M. aeruginosa toxic strain (IZANCYA 2), during 24 b. Cytosolic fractions of gills and digestive tract were analyzed by two-dimensional (2D) electrophoresis in 7 cm IPG strips (pH 4-7). On average, about 400 spots were resolved using Coomassie staining. Altered protein expression was quantitatively detected in 16-13 spots in gills and digestive tract, respectively. In 2D electrophoresis gel protein maps from gills, 10 of 16 spots were downregulated. In the digestive tract, the general tendency was an increase in the protein expression level after the exposure. The altered protein spots were excised and analyzed by MALDI-TOF-MS, with identification of 8 proteins in gills and 5 in the digestive tract. Most of the identified proteins are involved in cytoskeleton assembly. Metabolic proteins were also detected. These results are in agreement with predicted effects of PP1 and PP2A phosphatase inhibition as major effect of microcystins-related toxicity.

  20. Proteomic changes in Corbicula fluminea exposed to wastewater from a psychiatric hospital.

    Science.gov (United States)

    Bebianno, M J; Sroda, S; Gomes, T; Chan, P; Bonnafe, E; Budzinski, H; Geret, F

    2016-03-01

    The increase use of pharmaceutical compounds in veterinary practice and human population results in the ubiquitous presence of these compounds in aquatic ecosystems. Because pharmaceuticals are highly bioactive, there is concern about their toxicological effects in aquatic organisms. Therefore, the aim of this study was to assess the effects of an effluent from a psychiatric hospital (containing a complex mixture of 25 pharmaceutical compounds from eleven therapeutic classes) on the freshwater clam Corbicula fluminea using a proteomic approach. The exposure of C. fluminea to this complex effluent containing anxiolytics, analgesics, lipid regulators, beta blockers, antidepressants, antiepileptics, antihistamines, antihypertensives, antiplatelets and antiarrhythmics induced protein changes after 1 day of exposure in clam gills and digestive gland more evident in the digestive gland. These changes included increase in the abundance of proteins associated with structural (actin and tubulin), cellular functions (calreticulin, proliferating cell nuclear antigen (PCNA), T complex protein 1 (TCP1)) and metabolism (aldehyde dehydrogenase (ALDH), alcohol dehydrogenase, 6 phosphogluconate dehydrogenase). Results from this study indicate that calreticulin, PCNA, ALDH and alcohol dehydrogenase in the digestive gland and T complex protein 1 (TCP1)) and 6 phosphogluconate dehydrogenase in the gills represent useful biomarkers for the ecotoxicological characterization of psychiatric hospital effluents in this species.

  1. Sodium sulfate impacts feeding, specific dynamic action, and growth rate in the freshwater bivalve Corbicula fluminea.

    Science.gov (United States)

    Soucek, David John

    2007-08-01

    Sodium sulfate is a ubiquitous salt that reaches toxic concentrations due to mining and other industrial activities, yet is currently unregulated at the Federal level in the United States. Previous studies have documented reduced growth of clams downstream of sulfate-dominated effluents, altered bioenergetics in filter-feeding invertebrates, and interactions between sulfate and other toxicants. Therefore, the purpose of this study was to determine if sodium sulfate affects the bioenergetics of the filter-feeding, freshwater bivalve, Corbicula fluminea, and the mechanism by which the effects are elicited. In addition to measuring effects on feeding, respiration and growth rates, I evaluated the relative sensitivity of a green algae consumed by clams to determine if top-down or bottom-up effects might be exhibited under field conditions. This study demonstrated that sodium sulfate had no effect on basal metabolic rates, but significantly reduced the feeding, post-feeding metabolic, and growth rates of C. fluminea. The proposed mechanism for these impacts is that filtering rates are reduced upon exposure, resulting in reduced food consumption and therefore, preventing increased metabolic rates normally associated with post-feeding specific dynamic action (SDA). In the field, these effects may cause changes in whole stream respiration rates and organic matter dynamics, as well as alter uptake rates of other food-associated contaminants like selenium, the toxicity of which is known to be antagonized by sulfate, in filter-feeding bivalves.

  2. Laboratory and field evaluation of a biological monitoring system using Corbicula fluminea and Mulinia lateralis

    Energy Technology Data Exchange (ETDEWEB)

    Waller, W.T.; Allen, H.J.; Schwalm, F.U.; Acevedo, M.F.; Ammann, L.P.; Dickson, K.L.; Kennedy, J.H. [Univ. of North Texas, Denton, TX (United States); Morgan, E.L. [Tennessee Technological Univ., Cookeville, TN (United States)

    1995-12-31

    Laboratory and field experiments have been performed to evaluate a non-invasive biomonitoring system using the Asiatic clam Corbicula fluminea and Mulinia lateralis. C. fluminea was exposed to simulated episodic toxicity events in the laboratory using copper, diazinon, and regulated flow rates. Group behavior during these simulated events was compared to behavior during unstressed periods to develop a statistical model and an alarm criteria. Bayou Chico, Pensacola Bay, FL, was the site for field experiments in which M. lateralis was placed in situ to evaluate the performance of the biomonitoring system. The biomonitoring system consists of proximity sensors which detect an aluminum foil target attached to the valve of an organism. Valve movements of the clams are then digitally recorded using a personal computer. Data collected from remote sites are telemetered to the lab using short wave radio. In its final form, the authors envision an in situ biological monitoring system using bivalves deployed in aquatic systems in conjunction with automated monitoring systems like those found at USGS gauging stations. A tool such as this could be used as a warning system to increase the probability of detecting toxic events as they occur.

  3. [Effects of Corbicula fluminea bioturbation on the community composition and abundance of ammonia-oxidizing archaea and bacteria in surface sediments].

    Science.gov (United States)

    Wang, Xue; Zhao, Da-Yong; Zeng, Jin; Yu, Duo-Wei; Wu, Qing-Long

    2014-06-01

    To better understand the effects of Corbicula fluminea bioturbation on the ammonia-oxidizing microorganisms in the surface sediment, sediment-water microcosms with different densities of Corbicula fluminea were constructed. Clone libraries and real-time qPCR were applied to analyze the community composition and abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in the surface sediments. The results obtained indicated that the bioturbation of Corbicula fluminea accelerated the release of nitrogen from the surface sediment. In the amoA gene clone libraries, the identified AOA amoA gene sequences affiliated with the two known clusters (marine and soil clusters). The identified AOB amoA gene sequences mostly belonged to the Nitrosomonas of beta-Proteobacteria. The abundance of the bacterial amoA gene was higher than that of the archaeal amoA gene in all treatments. With increasing density of Corbicula fluminea, decreased abundances of the bacterial amoA gene were observed. At the same time, the diversity of AOA and AOB reduced in the Corbicula fluminea containing microcosms. In conclusion, the bioturbation of Corbicula fluminea could affected the community composition and abundance of ammonia-oxidizing microorganisms in surface sediments.

  4. Seasonal variations of selected herbicides and related metabolites in water, sediment, seaweed and clams in the Sacca di Goro coastal lagoon (Northern Adriatic).

    Science.gov (United States)

    Carafa, R; Wollgast, J; Canuti, E; Ligthart, J; Dueri, S; Hanke, G; Eisenreich, S J; Viaroli, P; Zaldívar, J M

    2007-11-01

    This study assesses the status of Sacca di Goro coastal lagoon (Northern Adriatic, Italy) with respect to watershed pollution. Because 80% of its watershed is devoted to agriculture, plant protection products and their metabolites were found in the water column, sediments (the upper 0-15 cm layer), macroalgae (Ulva rigida) and clams (Tapes philippinarum). Five seasonal sampling campaigns were performed from May 2004 to April 2005 and concentrations measured in five stations in the lagoon and six in the watershed. Relatively high concentrations of the s-triazine - terbuthylazine -, urea herbicides - diuron - and alachlor were detected through the year mainly at stations directly influenced by the Po di Volano inflow. The concentrations of products in use follow a clear seasonal pattern with spring peaks. This pattern is also visible in the sediments as well as in biota. Among metabolites, hydroxylated compounds prevailed, often with concentrations greater than those of the parent compounds. For the most part of the year, the concentrations in biota were close to detection limits, with concentration peaks in spring.

  5. Dynamics of protein phosphatase gene expression in Corbicula fluminea exposed to microcystin-LR and to toxic Microcystis aeruginosa cells.

    Science.gov (United States)

    Martins, José Carlos; Machado, João; Martins, António; Azevedo, Joana; OlivaTeles, Luís; Vasconcelos, Vitor

    2011-01-01

    This study investigated the in vivo effects of microcystins on gene expression of several phosphoprotein phosphatases (PPP) in the freshwater clam Corbicula fluminea with two different exposure scenarios. Clams were exposed for 96 h to 5 μg L(-1) of dissolved microcystin-LR and the relative changes of gene expression of three different types of PPP (PPP1, 2 and 4) were analyzed by quantitative real-time PCR. The results showed a significant induction of PPP2 gene expression in the visceral mass. In contrast, the cyanotoxin did not cause any significant changes on PPP1 and PPP4 gene expression. Based on these results, we studied alterations in transcriptional patterns in parallel with enzymatic activity of C. fluminea for PPP2, induced by a Microcystis aeruginosa toxic strain (1 × 10(5) cells cm(-3)) during 96 h. The relative changes of gene expression and enzyme activity in visceral mass were analyzed by quantitative real-time PCR and colorimetric assays respectively. The clams exhibited a significant reduction of PPP2 activity with a concomitant enhancement of gene expression. Considering all the results we can conclude that the exposure to an ecologically relevant concentration of pure or intracellular microcystins (-LR) promoted an in vivo effect on PPP2 gene expression in C. fluminea.

  6. Dynamics of Protein Phosphatase Gene Expression in Corbicula fluminea Exposed to Microcystin-LR and to Toxic Microcystis aeruginosa Cells

    Directory of Open Access Journals (Sweden)

    Vitor Vasconcelos

    2011-12-01

    Full Text Available This study investigated the in vivo effects of microcystins on gene expression of several phosphoprotein phosphatases (PPP in the freshwater clam Corbicula fluminea with two different exposure scenarios. Clams were exposed for 96 h to 5 µg L−1 of dissolved microcystin-LR and the relative changes of gene expression of three different types of PPP (PPP1, 2 and 4 were analyzed by quantitative real-time PCR. The results showed a significant induction of PPP2 gene expression in the visceral mass. In contrast, the cyanotoxin did not cause any significant changes on PPP1 and PPP4 gene expression. Based on these results, we studied alterations in transcriptional patterns in parallel with enzymatic activity of C. fluminea for PPP2, induced by a Microcystis aeruginosa toxic strain (1 × 105 cells cm−3 during 96 h. The relative changes of gene expression and enzyme activity in visceral mass were analyzed by quantitative real-time PCR and colorimetric assays respectively. The clams exhibited a significant reduction of PPP2 activity with a concomitant enhancement of gene expression. Considering all the results we can conclude that the exposure to an ecologically relevant concentration of pure or intracellular microcystins (-LR promoted an in vivo effect on PPP2 gene expression in C. fluminea.

  7. Field transplantation of the freshwater bivalve Corbicula fluminea along a polymetallic contamination gradient (River Lot, France): 1. Geochemical characteristics of the sampling sites and cadmium and zinc bioccumulation kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Andres, S.; Baudrimont, M.; Lapaquellerie, Y.; Ribeyre, F.; Maillet, N.; Latouche, C.; Boudou, A.

    1999-11-01

    Specimens of the Asiatic clam Corbicula fluminea were transplanted from a clean lacustrine site to four stations along a polymetallic gradient in the river Lot (France), downstream from an old Zn ore treatment facility. The bivalves were held in benthic cages for a 5-month exposure period, April to September 1996; mollusk growth and metal bioaccumulation kinetics (Cd, Zn) were followed by subsampling the cages at t = 0, 21, 49, 85, 120, and 150 d. Rates of Cd bioaccumulation in the whole soft bodies and in individual organs were greater at the upstream stations located close to the pollution source, but there was no direct proportionality between Cd in the bivalves and in the unfiltered or filtered river water samples. Unlike the case for Cd, rates of Zn bioaccumulation did not reflect the contamination gradient. Marked growth differences were measured among the four stations, reflecting both nutritional differences and changes in the degree of metal contamination; these growth differences produced markedly different trends when metal bioaccumulation was expressed in terms of burdens rather than concentrations.

  8. 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... Nonstandardized Foods § 102.49 Fried clams made from minced clams. (a) The common or usual name of the food product that resembles and is of the same composition as fried clams, except that it is composed of...

  9. Low Genetic Diversity and High Invasion Success of Corbicula fluminea (Bivalvia, Corbiculidae) (Müller, 1774) in Portugal.

    Science.gov (United States)

    Gomes, Cidália; Sousa, Ronaldo; Mendes, Tito; Borges, Rui; Vilares, Pedro; Vasconcelos, Vitor; Guilhermino, Lúcia; Antunes, Agostinho

    2016-01-01

    The Asian clam, Corbicula fluminea, is an invasive alien species (IAS) originally from Asia that has spread worldwide causing major ecological and economic impacts in aquatic ecosystems. Here, we evaluated C. fluminea genetic (using COI mtDNA, CYTb mtDNA and 18S rDNA gene markers), morphometric and sperm morphology variation in Portuguese freshwater ecosystems. The COI marker revealed a single haplotype, which belongs to the Asian FW5 invasive lineage, suggesting a common origin for all the 13 Portuguese C. fluminea populations analysed. Morphometric analyses showed differences between the populations colonizing the North (with the exception of the Lima River) and the Centre/South ecosystems. The sperm morphology examination revealed the presence of biflagellate sperm, a distinctive character of the invasive androgenetic lineages. The low genetic variability of the Portuguese C. fluminea populations and the pattern of sperm morphology have been illuminating for understanding the demographic history of this invasive species. We hypothesize that these populations were derived from a unique introductory event of a Corbicula fluminea FW5 invasive androgenic lineage in the Tejo River, which subsequently dispersed to other Portuguese freshwater ecosystems. The C. fluminea asexual reproductive mode may have assisted these populations to become highly invasive despite the low genetic diversity.

  10. Low Genetic Diversity and High Invasion Success of Corbicula fluminea (Bivalvia, Corbiculidae (Müller, 1774 in Portugal.

    Directory of Open Access Journals (Sweden)

    Cidália Gomes

    Full Text Available The Asian clam, Corbicula fluminea, is an invasive alien species (IAS originally from Asia that has spread worldwide causing major ecological and economic impacts in aquatic ecosystems. Here, we evaluated C. fluminea genetic (using COI mtDNA, CYTb mtDNA and 18S rDNA gene markers, morphometric and sperm morphology variation in Portuguese freshwater ecosystems. The COI marker revealed a single haplotype, which belongs to the Asian FW5 invasive lineage, suggesting a common origin for all the 13 Portuguese C. fluminea populations analysed. Morphometric analyses showed differences between the populations colonizing the North (with the exception of the Lima River and the Centre/South ecosystems. The sperm morphology examination revealed the presence of biflagellate sperm, a distinctive character of the invasive androgenetic lineages. The low genetic variability of the Portuguese C. fluminea populations and the pattern of sperm morphology have been illuminating for understanding the demographic history of this invasive species. We hypothesize that these populations were derived from a unique introductory event of a Corbicula fluminea FW5 invasive androgenic lineage in the Tejo River, which subsequently dispersed to other Portuguese freshwater ecosystems. The C. fluminea asexual reproductive mode may have assisted these populations to become highly invasive despite the low genetic diversity.

  11. Purification and characterization of a novel C-type hemolytic lectin for clot lysis from the fresh water clam Villorita cyprinoides: a possible natural thrombolytic agent against myocardial infarction.

    Science.gov (United States)

    Sudhakar, G R Learnal; Vincent, S G Prakash

    2014-02-01

    Villorita cyprinoides (black clam) is a fresh water clam that belongs as a bivalve to the group of mollusc. The saline extracts from the muscle reveal high titers of agglutination potency on trypsin-treated rabbit erythrocytes. With the help of affinity chromatography a hemolytic protein with lectin activity which could all be inhibited by D-galactose were isolated. The lectins were separated on DEAE-cellulose and the main component was purified after an additional step of gel filtration on sephadex G-75. The main component is a non-glycosylated protein with a molecular weight of 96,560 Da determined by MALDI-ToF, consisting of a single protein chain and characterized by the lack of polymers and intermediate disulfide bonds. The pure main lectin with clot lytic feature shows two bands at molecular weights 36,360 and 26, 520 Da. Optimal inhibition of the pure lectin is achieved by D-galactose containing oligo- and polysaccharides. The lectin activity decreased above 40 °C and was lost at 62 °C, the stability over the pH range between 7.0 and 8.0 and requires divalent cations for their activity. The novel C-type hemolytic lectin for clot lysis from the clam Villorita cyprinoides was identified and evaluated, the purified hemolytic lectin (0.35 mg/ml and 0.175 mg/ml) enhanced clot lysis activity when compared to the different concentration (5 mg/ml and 1 mg/ml) of commercial streptokinase. In the present study identified hemolytic lectin was a rapid and effective clot lytic molecule and could be developed as new drug molecule in future. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Responses of cytochrome P450, GST, and MXR in the mollusk Corbicula fluminea to the exposure to hospital wastewater effluents.

    Science.gov (United States)

    Bonnafé, Elsa; Sroda, Sophie; Budzinski, Hélène; Valière, Amélie; Pedelluc, Julie; Marty, Pierre; Geret, Florence

    2015-07-01

    Pharmaceutical products are a major group of chemical compounds that are continuously released into the environment. The primary pathway of pharmaceuticals to the aquatic environment is the discharge of wastewater effluents. The Psychiatric hospital of Montpon (Dordogne, France) operates with its wastewater treatment plant. We first evaluated the presence and concentrations of 27 pharmaceuticals compounds in these effluents. All of the 27 compounds were detected in these wastewater effluents at concentrations ranging between 37,500 ng L(-1) (paracetamol) and 150 ng L(-1) (citalopram). The aim of the study was then to evaluate the exposure effects of the effluents on cytochrome P450, GST, and MXR responses in Corbicula fluminea gills and digestive glands. Experiments on clams exposed during 1, 3, 7 14, and 21 days revealed a strong and continuous overexpression of mdr1 (multidrug resistant 1) gene expression in gills and transitory variations in pi-gst expression and GST activity. EROD activity increased also transitory after 1 day in the digestive gland of exposed clams. These results indicated that in the effluent, some molecules have undergone metabolism of phase 1 and/or phase 2.

  13. Biomarkers in the freshwater bivalve Corbicula fluminea confined downstream a domestic landfill leachate discharge.

    Science.gov (United States)

    de Oliveira, Luciana Fernandes; Santos, Caroline; Dos Reis Martinez, Claudia Bueno

    2016-07-01

    Landfills represent a severe environmental problem mainly due to the generation of leachates, and this study aimed to evaluate sublethal effects of a domestic landfill leachate in the freshwater bivalve Corbicula fluminea. Clams were submitted to in situ tests along a stream, at three sites, representing increasing distances from the leachate discharge (Pq1, Pq2, and Pq3), for 1, 5, and 15 days. The following biomarkers were analyzed in the gills and digestive glands: 7-ethoxyresorufin-O-deethylase (EROD) and glutathione S-transferase (GST) activities, multixenobiotic resistance mechanism (MXR), total antioxidant capacity (TAC), reactive oxygen species (ROS), and lipid peroxidation (LPO). Metallothionein (MT) content was determined in the gills and DNA damage in hemocytes. The mortality rate of animals during in situ tests was reduced as the distance from the leachate discharge source increased. On the other hand, biomarker results showed sublethal effects on C. fluminea confined at all sites of PqS. GST, TAC, ROS, and DNA damage were the most significant biomarkers for this species and should be considered for future monitoring and assessment of freshwater environments located in landfill areas.

  14. Will Climate Change Help New York Hard Clams Fight Disease?

    Science.gov (United States)

    Dahl, S.; Allam, B.

    2016-02-01

    Warming trends will progress along with increased precipitation, particularly during winter and spring, in projections of climate change for the Northeastern US. Hard clams suffered significantly from QPX disease under cool water (13°C) laboratory treatments compared to warm water treatments (21°C and 27°C). Coastal New York (NY) waters are expected to experience more days of temperatures above 21°C. QPX related hard clam mortalities in the lab were greater under high (30ppt) vs low (17ppt) salinity treatments and in vitro studies have shown QPX growth to be inhibited by low salinities. Increased precipitation to watersheds and heavier river flow will alter estuarine salinity regimes that could restrict the distribution of QPX in hard clam habitats. Analysis of over ten years of infection and environmental monitoring data from Raritan Bay, a QPX enzootic estuary, reveals areas of lower salinity and higher summer temperatures have limited QPX infections. Climate change is often considered a source of potential stressors to marine organisms that increases their susceptibility to physiological ailments and opportunistic disease. In this particular scenario of QPX disease in NY coastal waters, climate change may become more detrimental to this specific opportunistic pathogen and could benefit the health of hard clam populations.

  15. Final Oahe Dam/Lake Oahe Master Plan Missouri River, South Dakota and North Dakota

    Science.gov (United States)

    2010-09-01

    water intake structures and cause ecological and economic damage in upper Midwest. Asian clam ( Corbicula fluminea ) Class 1 Corbicula are...freshwater natives of southern and eastern Asia. The sources and pathway of initial introductions are not well documented. Corbicula will cause the same

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

    Science.gov (United States)

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

    2014-10-01

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Growth and extremely high production of the non-indigenous invasive species Corbicula fluminea (Müller, 1774): Possible implications for ecosystem functioning

    Science.gov (United States)

    Sousa, Ronaldo; Nogueira, António J. A.; Gaspar, Miguel B.; Antunes, Carlos; Guilhermino, Lúcia

    2008-11-01

    The Asian clam Corbicula fluminea (Müller, 1774) is a major component of the River Minho estuary, almost completely dominating the benthic biomass. As part of a major study into the ecology of C. fluminea, benthic samples were collected monthly from January 2005 to August 2006. These data were then used to estimate the abundance, biomass, growth, and growth and elimination production of this non-indigenous invasive species. Corbicula fluminea growth was continuous throughout its life span. The annual 2005 growth production was estimated to be 463.778 g AFDW m -2 year -1, and the mean annual biomass was 160.651 g AFDW m -2, resulting in a P/B¯ ratio of 2.89 year -1 and a turnover time of 126.4 days. In the light of these results, C. fluminea is a fundamental element in the River Minho estuary, possibly sequestering a large portion of the carbon available for benthic production and altering the ecosystem functioning. This species should be considered when modelling the nutrient cycles and energy flow in aquatic ecosystems.

  18. Effect of transplantation on heavy metal concentrations in commercial clams of Lake Timsah, Suez Canal, Egypt

    Directory of Open Access Journals (Sweden)

    Howaida R. Gabr

    2008-03-01

    Full Text Available Ruditapes decussatus and Venerupis pullastra are commercially fished clamswith a wide distribution in the shallow inshore waters of Lake Timsah, Egypt.They are usually contaminated with heavy metals. Consumption of suchcontaminated clams can pose a public health risk. To minimise this risk,therefore, the clams should be removed from the contaminated waters andtransferred to an approved area to reduce the high levels of metals beforebeing marketed. The aim of this work was to study the effect of transplantation on levels of heavy metals(Fe, Mn, Zn, Cu, Ni, Co, Cd, Pb in these clams. The clams were removed from their polluted site and transplantedto a relatively clean area for a period of 120 days. Although the salinity atthe transplantation site was higher than at the polluted site, it was stableand did not appear to have any adverse effect on clam growth. Heavy metalswere analysed in the water, sediment and clam tissues from both the pollutedand the transplantation sites. Although in both species transplantationevidently reduced heavy metal levels, these still exceeded the maximumpermissible levels laid down by the WHO (1982.

  19. Feeding inhibition in Corbicula fluminea (O.F. Muller, 1774) as an effect criterion to pollutant exposure: Perspectives for ecotoxicity screening and refinement of chemical control.

    Science.gov (United States)

    Castro, Bruno Branco; Silva, Carlos; Macário, Inês Patrunilho Efe; Oliveira, Bruno; Gonçalves, Fernando; Pereira, Joana Luísa

    2018-03-01

    Bivalves are commonly used in biomonitoring programs to track pollutants. Several features, including its filter-feeding abilities, cumulatively argue in favour of the use of the Asian clam (Corbicula fluminea) as a biosentinel and an ecotoxicological model. Filtration in bivalves is very sensitive to external stimuli and its control is dictated by regulation of the opening/closure of the valves, which may be used as an avoidance defence against contaminants. Here, we investigate the filter-feeding behaviour of the Asian clam as an endpoint for assessing exposure to pollutants, driven by two complementary goals: (i) to generate relevant and sensitive toxicological information based on the ability of C. fluminea to clear an algal suspension, using the invasive species as a surrogate for native bivalves; (ii) to gain insight on the potential of exploring this integrative response in the refinement of chemical control methods for this pest. Clearance rates and proportion of algae removed were measured using a simple and reproducible protocol. Despite some variation across individuals and size classes, 50-90% of food particles were generally removed within 60-120 min by clams larger than 20 mm. Removal of algae was sensitive to an array of model contaminants with biocide potential, including fertilizers, pesticides, metals and salts: eight out of nine tested substances were detected at the μg l -1 or mg l -1 range and triggered valve closure, decreasing filter-feeding in a concentration-dependent manner. For most toxicants, a good agreement between mortality (96 h - LC 50 within the range 0.4-5500 mg l -1 ) and feeding (2 h - IC 50 within the range 0.005-2317 mg l -1 ) was observed, demonstrating that a 120-min assay can be used as a protective surrogate of acute toxicity. However, copper sulphate was very strongly avoided by the clams (IC 50  = 5.3 μg l -1 ); on the contrary, dichlorvos (an organophosphate insecticide) did not

  20. The Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment

    Science.gov (United States)

    Smith, William L., Jr.; Charlock, Thomas; Wielicki, Bruce; Kahn, Ralph; Martins, J. Vanderlei; Gatebe, Charles; Hobbs, Peter V.; Purgold, G. Carl; Redemann, Jens; Remer, Lorraine

    2004-01-01

    NASA has developed an Earth Observing System (EOS) consisting of a series of satellites designed to study global change from space. The EOS flagship is the EOS TERRA satellite, launched in December 1999, equipped with five unique sensors to monitor and study the Earth s heat budget and many of the key controlling variables governing the Earth's climate system. CLAMS, the Chesapeake Lighthouse and Aircraft Measurements for Satellites field campaign was conducted from NASA Wallops Flight Facility and successfully executed over the middle Atlantic eastern seaboard from July 10 August 2, 2001. CLAMS is primarily a shortwave closure experiment designed to validate and improve EOS TERRA satellite data products being derived from three sensors: CERES (Clouds and Earth's Radiant Energy System), MISR (Multi-angle Imaging Spectro-Radiometer) and MODIS (MODerate Resolution Imaging Spectroradiometer). CLAMS is jointly sponsored by the CERES, MISR and MODIS instrument teams and the NASA GEWEX Global Aerosol Climatology Project (GACP). CLAMS primary objectives are to validate satellite-based retrievals of aerosol properties and vertical profiles of radiative flux, temperature and water vapor. Central to CLAMS measurement strategy is the Chesapeake Lighthouse, a stable sea platform located in the Atlantic Ocean, 13 miles east of Virginia Beach near the mouth of the Chesapeake Bay and the site of an ongoing CERES Ocean Validation Experiment (COVE). Six research aircraft were deployed to make detailed measurements of the atmosphere and ocean surface in the vicinity of COVE, over the surrounding ocean, over nearby NOAA buoys and over a few land sites. The measurements are used to validate and provide ground truth for simultaneous products being derived from TERRA data, a key step toward an improved understanding and ability to predict changes in the Earth's climate. One of the two CERES instruments on-board TERRA was programmed for Rotating Azimuth Plane Scans (RAPS) during CLAMS

  1. Elimination of Escherichia coli and Salmonella in Clam by Using Zeolite in a Station of Depuration.

    Science.gov (United States)

    Gdoura, Morsi; Sellami, Hanen; Khannous, Lamia; Ketata, Najib; Neila, Idriss Ben; Traore, Al Ibrahim; Chekir, Zouhair; Gdoura, Radhouane

    2017-09-01

      The application of natural zeolite for water and wastewater treatment has been carried out and is still a promising technique in environmental cleaning processes. Natural zeolite can be used to improve the purification process of clams (Ruditapes decussatus). Thus, our study aimed at improving the clam purification system in order to reduce Escherichia coli and eliminate Salmonella in samples artificially contaminated with this bacterium using a natural zeolite to replace the biological filter. The results showed that zeolite used in a depuration system improved the clam purification process. Moreover, natural zeolite exhibited high performance in the adsorption of bacteria and allowed to reduce the Escherichia coli abundance in 24 h, thus ensuring purified clams conformity with the ISO 16649-3 standard. These results indicate the beneficial effects of using zeolite in the adsorption of bacteria and the reduction in the abundance of Escherichia coli and set the Salmonella from marine organisms.

  2. Selenium bioaccumulation in Chlamydomonas reinhardtii and subsequent transfer to Corbicula fluminea: role of selenium speciation and bivalve ventilation.

    Science.gov (United States)

    Fournier, Elodie; Adam, Christelle; Massabuau, Jean-Charles; Garnier-Laplace, Jacqueline

    2006-10-01

    The uptake of Se by the freshwater alga Chlamydomonas reinhardtii and the subsequent transfer to the Asiatic clam Corbicula fluminea was investigated. The objective was to investigate the bioavailability of algal-bound Se for C. fluminea while taking into account Se speciation and bivalve ventilation. First, uptake rates of waterborne Se (selenite, selenate, and selenomethionine) in the algae during a 1-h exposure period were determined for a range of concentrations up to 2,000 microg/L. Fluxes for selenite uptake were constant in the range of concentrations tested, whereas fluxes for selenate and selenomethionine uptake decreased with increasing concentrations, suggesting a saturated transport system at high concentrations (approximately 1,000 microg/L for selenate and 100 microg/L for selenomethionine). These data were used to set the algal contamination for the study of trophic transfer to the clam. Three parameters were studied: The Se form, the algal density, and the Se burden in the algae. The results show that for a fixed algal density, an Se-contaminated algal diet does not modify ventilation. In this case, the driving factor for ventilation is the algal density, with ventilation being enhanced for low algal densities. On the basis of ventilatory flow rate measurements and Se burdens in algae, it was found that bioaccumulation of Se in C. fluminea was proportional to the total quantity of Se passing through the whole organism, but with a lesser extraction coefficient for selenomethionine than for the inorganic forms. These results underline the importance of both physiological factors and speciation in understanding the trophic transfer of Se.

  3. Toxicity of chromium, copper and zinc to freshwater clam ( Galatea ...

    African Journals Online (AJOL)

    The results revealed that death occurred in the water treated with toxicants but no death occurred in the control experiment, indicating that all deaths recorded were due to the toxicants. The 96-hour LC50 values obtained were 2.51mgL-1 for copper, 91.2mgL-1 for zinc indication that copper was most toxic to the clams ...

  4. 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 < 0.05). There were no significant differences in the levels of white blood cells, interleukin (IL)-6, or IL-10. The wound areas of the NS group (23.9%) were larger than those in the FCE group (8.26%) on day 14 (P < 0.05). Numerous fibroblasts and collagen fiber organization were observed in the FCE group. FCE supplementation improves the wound healing process. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, S.; Huang, Q.; Li, C. [Institute of Plasma Physics, Chinese Academy of Sciences, Anhui (China)

    2007-07-01

    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)

  6. Corbiculae fluminea as a bioindicator on the Lower Colorado River

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Tissue samples from Asiatic clam (Corbimla fluminea) from the lower Colorado River were analyzed for trace element concentrations. Selenium and arsenic were elevated...

  7. 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 (<0.1% of cells abnormal), hemocytes from normal soft shell clams, and normal soft shell clam tissues did not produce a positive reaction in the PCR enhanced reverse transcriptase assay.

  8. REVIEW: Symbiosis between the Giant Clams (Bivalvia: Cardiidae and Zooxanthellae (Dinophyceae

    Directory of Open Access Journals (Sweden)

    UDHI EKO HERNAWAN

    2008-01-01

    Full Text Available Giant clams are the largest bivalves in the world that maintain a mutual relationship with zooxanthellae. Individual giant clam can harbor heterogeneous zooxanthellae, at least four taxa in genus Symbiodinium. The Symbiodinium lives in the zooxanthellal tubular system, a tube structure arising from one of the diverticular duct of the clam’s stomach. Since the numbers of zooxanthellae is the one of some significant factors contributing to the clams growth and survival, the giant clams need to adjust the number of zooxanthellae for physiological reason with unclear mechanism. The important role of the symbiotic relationship to the clams can be seen on the survival, growth and nutrition of the clams. There are at least two significant factors determining the symbiosis, i.e. water temperature in related with level of light intensities and ammonium-phosphate rate. Some topic is still unclear, i.e. the determination of species in genus Symbiodinium, the mechanism for adjusting the population numbers of the algae and what kind of environmental factors determining the symbiosis. Thereby further research is still needed to clarify those missing.

  9. 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.

  10. Inhibitory effects of chloroform extracts derived from Corbicula fluminea on the release of pro-inflammatory cytokines.

    Science.gov (United States)

    Lin, Ching-Min; Lin, Yu-Ling; Tsai, Nu-Man; Wu, Hsin-Yi; Ho, Shu-Yi; Chen, Chia-Hung; Liu, Yen-Ku; Chiu, Yi-Han; Ho, Li-Ping; Lee, Ru-Ping; Liao, Kuang-Wen

    2012-04-25

    Corbicula fluminea, the primary freshwater bivalve cultivated in Taiwan, was formerly used as a remedy for hepatitis. Recent reports indicate that C. fluminea has many bioactivities, but it remains unknown whether C. fluminea affects inflammation. This study explored the anti-inflammatory activity of C. fluminea. C. fluminea was first treated with chloroform to obtain clam chloroform extracts (CCEs). On the basis of the assay for the release of pro-inflammatory cytokines in vitro and in vivo, the results show that the CCEs significantly lowered the release of lipopolysaccharide (LPS)-induced pro-inflammatory cytokines. Additionally, the CCEs reduced LPS-induced organ damage. Real-time polymerase chain reaction analysis suggested that CCEs inhibit the LPS-induced mRNA expression of interleukin-1β and tumor necrosis factor-α. Western blot analysis indicated that the CCEs increased expression of IκB and attenuated the phosphorylation of IκB. Gas chromatography-mass spectrometry suggests that phytosterols and fatty acids are responsible for the anti-inflammatory properties of CCEs. Taken together, CCEs have the potential to be developed as an anti-inflammatory functional food.

  11. 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...

  12. 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.

  13. A review of the occurrence of Corbicula in the Pleistocene of North-West Europe

    NARCIS (Netherlands)

    Meijer, T.; Preece, R.C.

    2000-01-01

    Shells belonging to the bivalve genus Corbicula occur commonly in Pleistocene interglacial deposits in NW Europe. These have usually been identified as C. fluminalis, a modern species described from the Euphrates river, although the veracity of this specific attribution remains equivocal. Corbicula

  14. Effect of chronic selenium exposure on the freshwater bivalve Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, E.; Adam, C.; Massabuau, J.C.; Garnier-Laplace, J. [CEA Cadarache (DEI/SECRE/LRE), Laboratory of Radioecology and Ecotoxicology, Institute for Radioprotection and Nuclear Safety, 13 - Saint-Paul-lez-Durance (France)

    2004-07-01

    Selenium is essential for most of living organisms. In oxic to moderately oxic fresh-waters, Se exists predominantly in the (+VI) and (+IV) oxidation states as selenate (SeO{sub 4}{sup 2-}) and selenite (SeO{sub 3}{sup 2-}) respectively, whereas in the biota it is incorporated as Se(-II) into seleno-proteins or amino-acids, or as elemental selenium Se(0). At low concentrations, it acts against oxidative damages mainly as the glutathione peroxidase seleno-dependant, but it may be toxic at higher levels (for example, by replacing sulphur in important biomolecules). In filter feeders, such as the freshwater bivalve Corbicula fluminea, selected as biological model, the ventilation activity is a primary limiting step that controls the water influx and therefore the delivery of contaminants. Consequently, a series of short-term experiments were performed to study the effects of different dissolved Se concentrations and forms (selenite; selenate; selenomethionine) on the ventilation activity of Corbicula fluminea and Se tissular distribution. The modification of the ventilation activity of the Se-exposed groups, in comparison to this of reference groups (not exposed to Se) varied greatly according to the form and the concentrations of the Se used. Se concentrations in tissues indicated that selenite was the less bioavailable form whereas selenomethionine displayed the opposite trend. On the basis of this set of experiments, a limited number of conditions have been selected to provide highly contrasting ventilation flow rates and selenium bioaccumulation levels, in order to study the effects of long term exposures, i) at the molecular level, by measuring bio-markers of oxidative stress (forms of glutathione, glutathione peroxidase, glutathione reductase, superoxide dismutase, catalase, and bio-marker of genotoxicity (comet assay), ii) at the (sub)cellular level by analysing Se micro-localisation in target organs and iii) at the individual level by monitoring the variation

  15. High parasite burden increases the surfacing and mortality of the manila clam (Ruditapes philippinarum) in intertidal sandy mudflats on the west coast of Korea during hot summer.

    Science.gov (United States)

    Nam, Ki-Woong; Jeung, Hee-Do; Song, Jae-Hee; Park, Kwan-Ha; Choi, Kwang-Sik; Park, Kyung-Il

    2018-01-18

    Over the past few decades, mass mortality events of Manila clams have been reported from several tidal flats on the west coast of Korea during hot summers. During such mortality events, once clams simultaneously surface, they fail to re-burrow, perishing within a week. The present study aimed to identify the possible causes of the mass mortality of this clam species by investigating the Perkinsus olseni parasite burden and immune parameters of surfaced clams (SC) and normal buried clams (NBCs) when sea water or sediment temperature in the study area varied from 25 °C to 34 °C from late July through mid-August 2015. We collected 2 groups of clams distributed within a 10-m2 area when a summer clam mortality event occurred around Seonyu-do Island on the west coast of Korea in 2015. The clams were collected 2 days after they surfaced on the sediment and still looked healthy without any gaping. The clams were transported to the laboratory, and we compared P. olseni infection intensity and cell-mediated hemocyte parameters between the NBCs and SCs. SCs showed significantly higher levels of P. olseni burden, lower condition index, and lower levels of cell-mediated immune functions than those of NBCs. Our study suggests that high P. olseni infection weakens Manila clams' resistance against thermal stress, causing them to surface. We surmise that the summer mass mortality of Manila clams on the west coast of Korea is caused by the combined effects of high P. olseni infection levels and abnormally high water temperature stress.

  16. 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.

  17. 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

  18. Use of Population Parameters in Examining Changes in the Status of the Short-Necked Clam Paphia undulata Born, 1778 (Mollusca, Pelecypoda: Veneridae in Coastal Waters of Southern Negros Occidental

    Directory of Open Access Journals (Sweden)

    Anabelle del Norte Campos

    2010-06-01

    Full Text Available Growth, recruitment, mortality and exploitation rate of the short-necked clam Paphia undulata (Born, 1778 were studied in southern Negros Occidental waters between August 2007 and July 2008 from length-frequency data derived from catches of divers, to be able to compare with earlier data derived and analyzed 13 years ago by Agasen et al. (1998. Both sets of data were analyzed using the FiSAT software (Gayanilo & Pauly, 1997. The asymptotic shell length (S¥ = 79 mm derived from the present data proved to be smaller compared to the earlier data (SL¥ = 81.5 mm due to the lack of bigger sizes in the present samples. The growth constant (K = 1.0 yr-1 was however comparable indicating it to be a more species-characteristic parameter. Two recruitment pulses for each study were derived and were found to be correlated with the spawning pattern in the species. The value of natural mortality (M = 1.57 yr-1 derived from bivalve literature, is deemed more appropriate compared to the earlier estimate (M = 2.89 yr-1 based on Pauly’s (1980 empirical equation developed for fish. Total mortality (Z values for both studies were comparable, but a higher level of fishing mortality (F = 4.61 yr-1 was estimated for the present data set, thus resulting likewise in a higher exploitation rate (E = 0.75. These, together with fishery information from an accompanying paper (Villarta & del Norte-Campos, 2010, not only validate the earlier findings of overexploitation due to lack of management, but reveal a worsening condition of the stock, most likely as a result of growth overfishing. Overexploitation can only be mitigated by imposing stringent restrictions in terms of the minimum size for exploitation (45 mm shell length and closed seasons during the spawning peak (August-November.

  19. Climate, Clams, and a Changing Watershed: A time series analysis to quantify the impact of management and climate on water quality in the Potomac Estuary

    Science.gov (United States)

    The Potomac River is the largest tributary of the Chesapeake Bay and has been a key study site in water quality research, beginning with work to address public health concerns such as safe drinking water and waterborne disease during periods of population growth and urbanization ...

  20. Stable oxygen and carbon isotope profiles in an invasive bivalve ( Corbicula fluminea) in North Carolina watersheds

    Science.gov (United States)

    Bucci, John P.; Showers, William J.; Genna, Bernie; Levine, Jay F.

    2009-06-01

    The modern invasive bivalve Corbicula fluminea was collected in 2006 from three sites with different land uses located in a North Carolina River Basin. The primary objective was to describe the δ 18O and δ 13C profiles of C. fluminea shells under various land use conditions. An additional aim was to evaluate whether growth patterns of C. fluminea form seasonally. Annual shell growth patterns were measured from the umbo to the margin and co-varied with estimates of ambient water temperature, corresponding to seasonal variation. The C. fluminea growth patterns as translucent bands (slower growth) appeared to form during winter months and opaque bands (rapid growth) formed during summer. A mixed model analysis (ANOVA) showed a significant site level effect of δ 18O and δ 13C profiles examined among sites ( F = 17.1; p = 0.003). A second model showed a borderline significant site effect among profiles with variability more pronounced at the urban site, Crabtree Creek ( p = 0.085). Previous habitat assessment ratings and water chemistry measurements suggested that the urban site was more impacted by storm water runoff. Understanding δ 18O and δ 13C SHELL profiles and shell growth patterns of the invasive bivalve ( C. fluminea) may help establish a framework for using these animals as biomonitors to record water temperature and nutrient pollution.

  1. 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…

  2. Effect of "heat shock" treatments on QPX disease and stress response in the hard clam, Mercenaria mercenaria.

    Science.gov (United States)

    Wang, Kailai; Pales Espinosa, Emmanuelle; Allam, Bassem

    2016-07-01

    The hard clam, Mercenaria mercenaria, is one of the most valuable commercial mollusk species along the eastern coast of the United States. Throughout the past 2 decades, the hard clam industry in the Northeast was significantly impacted by disease outbreaks caused by a lethal protistan parasite known as Quahog Parasite Unknown (QPX). QPX is an opportunistic pathogen and the infection has been shown to be a cold water disease, where warmer conditions (above 21°C) lead to disease reduction and clam healing. In vitro studies also showed a sharp reduction in parasite growth and survivorship at temperatures exceeding 27°C. In this study, we evaluated the effect of short-term exposures to high temperatures on QPX disease dynamic and clam recovery. Infected clams were collected from an enzootic site and subsequently submitted to one of ten "heat shock" treatments involving a gradient of temperatures and exposure times. QPX prevalence was compared before and 10weeks after heat shock to assess the effect of each treatment on disease progress. Expression of several stress-related genes was measured 1 and 7days after heat shock using qPCR to evaluate the effect of each treatment on clam physiology. Anti-QPX activity in clam plasma was also measured in an attempt to link changes in defense factors to thermal stress and disease progress. Our results suggest that brief exposures to moderate high temperatures promote the greatest remission while imposing the mildest stress to clams. These results are discussed with the aim of providing the industry with possible strategies to mitigate QPX disease. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Impact of High Hydrostatic Pressure on the Shelling Efficacy, Physicochemical Properties, and Microstructure of Fresh Razor Clam (Sinonovacula constricta).

    Science.gov (United States)

    Xuan, Xiao-Ting; Cui, Yan; Lin, Xu-Dong; Yu, Jing-Feng; Liao, Xiao-Jun; Ling, Jian-Gang; Shang, Hai-Tao

    2018-01-22

    The effects of high hydrostatic pressure (HHP) treatments (200, 300, and 400 MPa for 1, 3, 5 and 10 min) on the shelling efficacy (the rate of shelling, the rate of integrity and yield of razor clam meat) and the physicochemical (drip loss, water-holding capacity, pH, conductivity, lipid oxidation, Ca2+ -ATPase activity, myofibrillar protein content), microbiological (total viable counts) and microstructural properties of fresh razor clam (Sinonovacula constricta) were investigated. HHP treatments significantly (P clam showed lower levels of microorganisms and drip loss than untreated razor clam. Levels of thiobarbituric acid reacting substances (TBA) in HHP-treated razor clam were greatly increased (up to 0.93 ± 0.09 mg MDA/kg at 400 MPa for 10 min) which was caused by the formation of hydroperoxides during HHP treatment. All HHP treatments were found to have adverse effects on the activity of Ca2+ -ATPase and the content of myofibrillar protein (MP), which might be due to the substantial damage to the tertiary structure of proteins at high pressure. Moreover, scanning electron microscopy (SEM) revealed the compaction of the muscle fibers and a decrease in the extracellular space with increasing pressure and holding time. This phenomenon was mainly correlated with the compaction of muscle fibers and denaturation, aggregation, and gelation of muscle protein triggered by high pressure. In general, HHP could be applied as a safe and effective nonthermal technology to produce high-quality shelled razor clam. High hydrostatic pressure (HHP) is now well known as a nonthermal processing technology and becoming increasingly acknowledged. However, it has not been widely applied to shell seafood due to its uncertain influence on its quality and shelling property. This study could provide valuable information regarding the shelling efficacy, physicochemical properties, and microstructure of razor clam treated by HHP. And it demonstrated that HHP showed a positive impact on

  4. 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

  5. Changes in bioturbation of iron biogeochemistry and in molecular response of the clam Ruditapes decussates upon Perkinsus olseni infection.

    Science.gov (United States)

    Simão, Márcio F; Leite, Ricardo B; Rocha, Carlos; Cancela, M Leonor

    2010-10-01

    A series of artificial microcosms was used to test the effect of clam density on benthic iron biogeochemistry and, subsequently, if the response of clam Ruditapes decussatus to infection with Perkinsus olseni, a common opportunistic parasite known to be iron dependent, was correlated with the dynamics of iron sediment pore waters within the chambers. Three series of benthic microcosms were used in the experiment, comparing similar densities of clams (none, one, two, three, or four individuals/chamber) between a control set (no deliberate infection) and two parallel sets of clams that were deliberately infected with the parasite after 10 days of incubation. Fifteen chambers were used simultaneously and the experiment was conducted for 35 days. In order to avoid spurious effects of differential organic loading and clam feeding efficiency on the oxidative state of the sediment, the iron balance was tentatively shifted during incubation toward decreased dissolved iron in pore water. This was done by applying a constant flow of air to all chambers and refraining from supplying extra organic matter during the experimental run, which led to the reduction of benthic oxygen demand as the experiment progressed. Results showed that microcosms bearing both higher clam densities and lower infection levels were able to exert a quantitative influence in iron biogeochemistry through bioturbation activity. This effect was significantly depressed in chambers hosting clams with high infection levels. In addition, analysis of molecular markers responsive to iron and parasite stress revealed an upper regulation of HSP70 and ferritin in infected clams, thus suggesting a role of those molecules on both host protection and response to parasite presence by limiting iron availability. Together, these findings suggest a correlation between the expression of clam molecular iron/stress markers and iron bioavailability, which can be modified by the presence or absence of Perkinsus infection. In

  6. Field transplantation of the freshwater bivalve Corbicula fluminea along a polymetallic contamination gradient (River Lot, France): 2. Metallothionein response to metal exposure

    Energy Technology Data Exchange (ETDEWEB)

    Baudrimont, M.; Andres, S.; Metivaud, J.; Lapaquellerie, Y.; Ribeyre, F.; Maillet, N.; Latouche, C.; Boudou, A.

    1999-11-01

    Specimens of the Asiatic clam Corbicula fluminea were transplanted from a clean lacustrine site to four stations along a polymetallic pollution gradient in the river Lot, France, downstream from an old Zn ore treatment facility (see Part 1). From April to September 1996, the authors studied Cd and Zn bioaccumulation and the metallothionein-like metal-binding protein (MT) concentrations by subsampling the ages at t = 0, 21, 49, 85, 120, and 150 d. Marked differences were observed among the four stations. At the most polluted station Riou-Mort, MT concentrations did not increase despite very rapid metal accumulation; all mollusks died between days 49 and 85, suggesting that the metal detoxification mechanisms were overwhelmed at this station. At the next station downstream, the final levels of bioaccumulated metal after 150 d were as high as those at the Riou-Mort station, but in this case the MT concentrations also increased progressively with positive correlations between MT and metal concentrations; no mortality was observed, but a significant growth inhibition was revealed in comparison to the reference site, with a lack of correlation between MT and reduced growth. Subcellular metal partitioning, as determined by size-exclusion chromatography, revealed that most of the Cd was sequestered by MT. In contrast, most of the Zn was bound to low molecular weight proteins, the MT fraction representing only 12% of cytosolic zn. These data show the marked role of MT toward Cd bioaccumulation and toxic effects on this freshwater bivalve species.

  7. 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.

  8. 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.

  9. Evaluation of the potential impact of polluted sediments using Manila clam Ruditapes philippinarum: bioaccumulation and biomarker responses.

    Science.gov (United States)

    Won, Eun-Ji; Hong, Seongjin; Ra, Kongtae; Kim, Kyung-Tae; Shin, Kyung-Hoon

    2011-08-01

    An assessment was made to monitor the short-term impact of heavily polluted sediments that may move out from the brackish man-made Lake Shihwa outside of the sea dike due to operations of a tidal power plant. Here, we exposed the Manila clam Ruditapes philippinarum collected from the western coast of Korea to natural sediment under lab condition for 96 h. Sediments were collected from Lake Shihwa and outside of the sea dike representing polluted and reference conditions, respectively. The results of chemical analysis revealed that the concentrations of nonylphenol and heavy metals in water and sediment from the inner region of Lake Shihwa were significantly higher than those of reference sediments. After 48 and 96 h of exposure, 30 specimens of clams were sampled from each experimental condition, and concentrations of nonylphenol and metals were measured in clams, water, and sediments. Several biomarkers, including concentrations of metallothionein-like proteins, and activities of the antioxidant enzymes glutathione S-transferase and catalase were determined in clams to characterize the effects of polluted sediments to clams. After 96 h of exposure, R. philippinarum assimilated nonylphenol up to 71 times compared to initial concentrations. However, there was no apparent uptake of heavy metals into the clams. Additionally, antioxidant enzymes exhibited higher activities in clams exposed to the polluted sediment. The results of the present study with physiological responses in R. philippinarum suggest that sediment transportation caused by the operation of a tidal power plant in Lake Shihwa will have striking effects on benthic organisms in the adjacent coastal area.

  10. Modification of boundary layer momentum by the presence and pumping behavior of the bivalve clam, Mercenaria mercenaria, in a tidal channel

    Science.gov (United States)

    Delavan, S. K.; Webster, D. R.

    2009-11-01

    The presence and activity of biological organisms have the potential to modify turbulent boundary layer characteristics in natural field settings. To determine the effect of the presence and pumping behavior of the bivalve clam, Mercenaria mercenaria, on the boundary layer momentum, profiles were collected for flood tides in the tidal rivers adjacent to Wassaw Sound, Georgia, USA. Velocity profiles were collected simultaneously with two adjacent Acoustic Doppler Velocimeters for boundary layer flows above sediments with and without the presence of buried clams. Treatment sites included clams buried in mud sediments, sand sediments, downstream of oyster beds, and downstream of sea grass beds. We hypothesize that the modification of boundary layer momentum is unique to the treatment characteristics. Vertical profiles of mean velocity, turbulent kinetic energy, and Reynolds shear stress are calculated from the collected time records. Preliminary analysis suggests that flows downstream of sea grass and oyster beds are less affected by the presence of clams than flows over sand and mud flats. Clams reduce the horizontal velocity values above mud substrates when compared to adjacent measurements without clams present, particularly close to the substrate. When buried in sand flats, clams tend to increase the horizontal velocity values higher in the water column.

  11. Effects of permethrin on biomarkers in Mediterranean clams (Ruditapes decussatus).

    Science.gov (United States)

    Sellami, B; Khazri, A; Louati, H; Boufahja, F; Dellali, M; Sheehan, D; Aissa, P; Driss, M Ridha; Mahmoudi, E; Beyrem, H

    2014-05-01

    The present study was focused on the assessment of Catalase (CAT) and Acetylcholinesterase (AChE) activities in Mediterranean clams (Ruditapes decussatus) exposed to 50, 100 and 150 μg/L of Permethrin for 5, 10, 15, 20 and 25 days. In water, the measured concentrations of Permethrin in the treated aquariums were respectively 16.66, 38.24 and 55.61 μg/L. Results showed that CAT activity was increased after 5 days of exposure to high concentration reaching maximum value of 10.14 μmol/min/mg proteins after 25 days. However, no significant changes in AChE activity after 5 days of exposure were detected in all treated groups. AChE activity was significantly inhibited after 10 days with 100 and 150 μg/L and still depending on concentration and time. Maximum inhibition of AChE activity was reached after 25 days with the highest concentration of Permethrin. Our data indicated that exposure to Permethrin modifies biomarker profiles inducing oxidative stress and reducing AChE activity in Mediterranean clams.

  12. 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.

  13. 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.

  14. Uptake and metabolism of carbamazepine (CBZ) by clam Ruditapes decussatus and its effects in biochemical responses.

    Science.gov (United States)

    Abdelhafidh, Khazri; Ali, Mezni; Hassen, Khazri; Badreddine, Sellami; Jaume, Aceña; Sandra, Pérez; Ethel, Eljarrat; Damià, Barceló; Hamouda, Beyrem; Ezzeddine, Mahmoudi

    2017-07-25

    1. Laboratory experiments were carried out to assess uptake and metabolism of the epilepsy drug, carbamazepine and its consequent biological responses in marine clam (Ruditapes decussatus) a model non-target organism in ecotoxicology. 2. Clams were exposed to two nominal concentrations (C1 = 30 μg/L and C2 = 50 μg/L) of CBZ for a maximum period of 14 days. Analysis of CBZ and their metabolites in clam and water after exposure to two nominal concentrations of the pharmaceutical drug were performed using UPLC-HRMS analysis. CBZ accumulation reached an average tissue concentration of 1241.59 ng/g dw and 1664.33 ng/g dw at low and high nominal concentration, respectively. 3. Furthermore, a metabolite (3-hydroxy-CBZ) was detected in tissues indicating carbamazepine translocation and metabolism inside clam, suspect screening of CBZ glucuronides was also performed by accurate mass extraction but it could not be detected. 4.  Activities of antioxidant enzymes superoxide dismutase, catalase and gluthatione-S-transferase generally increased. Change in the contents of glutathione, malondialdehyde and protein carbonyl were also studied. 5.  Results indicated that the bioaccumulation of CBZ resulted in the changes of the antioxidant defense system and the production of ROS with the oxidative stress, ultimately induced alteration in lipid peroxidation and protein carbonyl.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hedouin, L. [International Atomic Energy Agency-Marine Environment Laboratory, 4 Quai Antoine 1er, MC-98000 Monaco (Monaco); Laboratoire de Biologie et d' Environnement Marins, FRE 2727, La Rochelle University, 22 Av. Michel Crepeau, F-17000 La Rochelle (France); Institut de Recherche pour le Developpement, Centre d' Oceanologie de Marseille, Station Marine d' Endoume, Rue de la Batterie des Lions, F-13007 Marseille (France); Metian, M. [International Atomic Energy Agency-Marine Environment Laboratory, 4 Quai Antoine 1er, MC-98000 Monaco (Monaco); Teyssie, J.-L. [International Atomic Energy Agency-Marine Environment Laboratory, 4 Quai Antoine 1er, MC-98000 Monaco (Monaco); Fowler, S.W. [International Atomic Energy Agency-Marine Environment Laboratory, 4 Quai Antoine 1er, MC-98000 Monaco (Monaco); Fichez, R. [Institut de Recherche pour le Developpement, Centre d' Oceanologie de Marseille, Station Marine d' Endoume, Rue de la Batterie des Lions, F-13007 Marseille (France); Warnau, M. [International Atomic Energy Agency-Marine Environment Laboratory, 4 Quai Antoine 1er, MC-98000 Monaco (Monaco)]. E-mail: m.warnau@iaea.org

    2006-07-31

    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.

  16. Uranium uptake by the freshwater bivalve Corbicula fluminea: links between speciation, bioavailability and effects

    Energy Technology Data Exchange (ETDEWEB)

    Adam, C.; Tran, D.; Simon, O.; Fournier, E.; Denison, D.; Massabuau, J.C.; Garnier-Laplace, J. [CEA Cadarache (DEI/SECRE/LRE), Laboratory of Radioecology and Ecotoxicology, Institute for Radioprotection and Nuclear Safety, 13 - Saint-Paul-lez-Durance (France)

    2004-07-01

    Within the framework of ENVIRHOM research programme, dealing with the chronic low-level exposure of ecosystems to radionuclides, a set of experiments was conducted to investigate the links between speciation, bioavailability and effects of uranium in the bivalve Corbicula fluminea. Short-term uptake experiments were performed to link speciation to bioavailability, while evaluating the competitive effect of cations (Ca{sup 2+}, Mg{sup 2+} and H{sup +}) and the influence of uranium ligands in solution. Longer-term experiments were also performed to gain knowledge on distribution and uptake mechanisms. The effect of uranium on the bivalve behaviour was studied through (1) the valve movement activity, recorded by means of impedance measurements taken with two electrodes stuck on each shell of the bivalve, the measured current varying according to the distance between the electrodes and (2) the ventilation rate, whose measurement is based on the calculation of the volume of water cleared of algae per unit time in a transiently closed system. Effect Concentrations giving a closure response for p percent of the bivalves (ECp), can be calculated from experiments of valve movement activity via a logistic regression model. The main results of these studies will be presented, with a focus on their potential use for operational applications such as monitoring programmes. (author)

  17. Internal distribution of uranium and associated genotoxic damages in the chronically exposed bivalve Corbicula fluminea.

    Science.gov (United States)

    Simon, Olivier; Floriani, Magali; Cavalie, Isabelle; Camilleri, Virginie; Adam, Christelle; Gilbin, Rodolphe; Garnier-Laplace, Jacqueline

    2011-08-01

    Uranium (U) internal distribution and involved effects in the bivalve Corbicula fluminea have been studied after direct chronic exposure (90 d, 10 μg.L-1). U distribution was assessed at the subcellular level (Metal Rich Granules -MRG-, pellets and cytosol fractions) in two main organs of the bivalve (gills and visceral mass). Micro-localisation was investigated by TEM-EDX analysis in the gills epithelium. DNA damage in gill and hemolymph samples was measured by the Comet assay. The 90-d exposure period led to a significant increase of U concentration in gills over time (× 5) and a large U quantity in subcellular granules in gills. Finally, a significant increase (× 2) in DNA damage was noted in exposed gills and haemocytes. This study shows that the accumulation levels and consequently the potential toxicity cannot be successfully predicted only on the basis of concentration in water or in tissues and subcellular fractions after chronic exposure. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Internal distribution of uranium and associated genotoxic damages in the chronically exposed bivalve Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Olivier, E-mail: olivier.simon@irsn.fr [Laboratoire de Radioecologie et Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat, 186 BP3, 13115 Saint Paul-Lez-Durance Cedex (France); Floriani, Magali; Cavalie, Isabelle; Camilleri, Virginie; Adam, Christelle; Gilbin, Rodolphe; 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)

    2011-08-15

    Uranium (U) internal distribution and involved effects in the bivalve Corbicula fluminea have been studied after direct chronic exposure (90 d, 10 {mu}g.L-1). U distribution was assessed at the subcellular level (Metal Rich Granules -MRG-, pellets and cytosol fractions) in two main organs of the bivalve (gills and visceral mass). Micro-localisation was investigated by TEM-EDX analysis in the gills epithelium. DNA damage in gill and hemolymph samples was measured by the Comet assay. The 90-d exposure period led to a significant increase of U concentration in gills over time (x5) and a large U quantity in subcellular granules in gills. Finally, a significant increase (x2) in DNA damage was noted in exposed gills and haemocytes. This study shows that the accumulation levels and consequently the potential toxicity cannot be successfully predicted only on the basis of concentration in water or in tissues and subcellular fractions after chronic exposure. - Highlights: > Relevant information concerning the chronic impact of uranium on biota is scarce. > We study its biological speciation to explain bioavailability, accumulation, toxicity. > 80% of U accumulated was measured in the pellet fraction (organelles + granules/MRG). > Chronic exposure to U induced genetic damage in gill and haemolymph cells of the bivalve.

  19. An attempt to use stable isotopes in clam spoilage assessment

    OpenAIRE

    Aníbal, J.

    2013-01-01

    Clams...One of the most popular and profitable molluscs exploited in rearing plots in the Mediterranean, used as a food source for centuries. Usually seafood and clam intoxications can have 3 origins: Toxins DSP, PSP, NSP, ASP Microorganisms Clostridium, Listeria, Vibrio, Escherichia, Salmonella,Spoiled food… Goal of this study: assess the potential use of carbon and nitrogen stable isotopes as spoilage indicators for clams (Ruditapes decussatus), in order to better understand and assess t...

  20. Uniaxial diffusion bonding of CLAM/CLAM steels: Microstructure and mechanical performance

    Science.gov (United States)

    Zhou, Xiaosheng; Liu, Yongchang; Yu, Liming; Liu, Chenxi; Sui, Guofa; Yang, Jianguo

    2015-06-01

    By performing a two-step uniaxial diffusion bonding, the reliable joining between CLAM/CLAM steels has been attained. The microstructures at the vicinity of the joint region and in base material were respectively investigated through OM, SEM and TEM. The joint interface was integrated, and no microstructural defects were observed. In the base material, small amount of austenite is retained as thin films between martensite laths, which was suggested to be related to the compressive deformation in diffusion bonding. As a candidate structural material for the first wall in fusion energy systems, the radiation resistance of CLAM steel would be deteriorated by the retained austenite. Tensile and impact tests were carried out to assess the reliability of the joints subjected to post bond heat treatment. All the tensile specimens fractured in the base CLAM steel, meaning the good joining between CLAM steels. However, due to the low impact absorbed energy of the joints, efforts should still be made to optimize the bonding technology and the post bond heat treatment further.

  1. Uniaxial diffusion bonding of CLAM/CLAM steels: Microstructure and mechanical performance

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiaosheng; Liu, Yongchang, E-mail: licmtju@163.com; Yu, Liming; Liu, Chenxi; Sui, Guofa; Yang, Jianguo

    2015-06-15

    By performing a two-step uniaxial diffusion bonding, the reliable joining between CLAM/CLAM steels has been attained. The microstructures at the vicinity of the joint region and in base material were respectively investigated through OM, SEM and TEM. The joint interface was integrated, and no microstructural defects were observed. In the base material, small amount of austenite is retained as thin films between martensite laths, which was suggested to be related to the compressive deformation in diffusion bonding. As a candidate structural material for the first wall in fusion energy systems, the radiation resistance of CLAM steel would be deteriorated by the retained austenite. Tensile and impact tests were carried out to assess the reliability of the joints subjected to post bond heat treatment. All the tensile specimens fractured in the base CLAM steel, meaning the good joining between CLAM steels. However, due to the low impact absorbed energy of the joints, efforts should still be made to optimize the bonding technology and the post bond heat treatment further.

  2. 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.

  3. Effects of 2,2',4,4'-tetrabromodipheny ether (BDE-47) on gonadogenesis of the manila clam Ruditapes philippinarum.

    Science.gov (United States)

    Liu, Peipei; Miao, Jingjing; Song, Ying; Pan, Luqing; Yin, Pengfei

    2017-12-01

    The reported adverse effects of Polybrominated diphenyl ether (PBDE) congeners on gonadogenesis in fish may also occur in marine bivalves especially the burrowing species such as manila clam Ruditapes philippinarum. In this study, clams were exposed to BDE-47 for 25days at 0, 0.1 and 1μg/L. By using the water temperature control method, gonadal maturation from resting to ripe stage were observed successively in both the control and the treatment groups during 25days. The results showed that exposure to BDE-47 at concentration below 1μg/L did not delay the gonadogenesis process of the clam R. philippinarum, and no evidence of adverse effects of BDE-47 on clam gonadal histology was observed. However, exposure to 1μg/L BDE-47 caused significant decreases of haemolymph testosterone levels in both female and male clams at day 5 and day 15. The mRNA expression of 3β-HSD in females exposed to BDE-47 was significantly decreased at day 5, while mRNA expression of 17β-HSD and CYP17 was not significantly changed in either sex. Exposure to BDE-47 also resulted in up-regulation of the mRNA expression of vitellogenin (Vtg) in both sexes and spermatogenesis associated protein 4-homolog (SAP4) in males. These results suggest a potential contribution of BDE-47 to reproductive disruption in the manila clams, especially in males. This study demonstrates the promising utility of water temperature control method in conjunction with histological endpoints and biomarkers such as mRNA levels of Vtg in determining the reproductive disturbances caused by EDCs on bivalves. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Cadmium Accumulation and Metallothionein Response in the Freshwater Bivalve Corbicula fluminea Under Hydrodynamic Conditions.

    Science.gov (United States)

    Geng, Nan; Wang, Chao; Wang, Peifang; Qi, Ning; Ren, Lingxiao

    2015-06-01

    Freshwater bivalves such as Corbicula fluminea (Müller) are useful biomonitors for cadmium pollution because they absorb heavy metals and accumulate them in their tissues. We exposed C. fluminea in the laboratory to natural and cadmium (Cd)-spiked sediments below flowing water in order to evaluate the organisms' Cd accumulation and metallothionein (MT) response under hydrodynamic conditions. The accumulation of Cd and the induction of MT in C. fluminea were determined at 0, 1, 3, 6, 10, 16, and 23 days. Hydrodynamic conditions, represented by a water flow rate of 14 or 3.2 cm/s, increased Cd accumulation in the visceral mass, gill, foot, and mantle of C. fluminea in the first 3 or 6 days in the natural sediment. Cd concentrations in the C. fluminea tissues kept increasing over time in the three treatments, and significant differences were observed in Cd accumulation after 6 (visceral mass), 10 (foot) and 16 (gill and mantle) days among the three groups. The MT concentrations were barely affected by hydrodynamic conditions and were significantly linearly related to the Cd concentration in the visceral mass in the natural sediment and binomially related to it in the Cd-spiked sediment. Hydrodynamic conditions enhanced the accumulation of Cd in the soft tissues of C. fluminea, especially in the Cd-spiked sediment, but stronger hydrodynamic forces did not increase Cd accumulation. MT may be considered an indicator for Cd accumulation in C. fluminea under hydrodynamic conditions, but only when the Cd concentrations in the tissue remain below the toxic threshold values.

  5. Differential substrate affinity between two giant clam species ...

    African Journals Online (AJOL)

    Giant clams have been mostly reported in the South Paci c and Indian Ocean. The aim of this study was to com- pare the substrate a nity between two species of giant clams, Tridacna maxima and T. squamosa. Field surveys were carried out in April and May 2016 within the reef areas of three geographically di erent sites ...

  6. An annotated list of the species of the genus Corbicula from Indonesia (Mollusca: Corbiculidae)

    NARCIS (Netherlands)

    Djajasasmita, Machfudz

    1977-01-01

    The species of the genus Corbicula known from Indonesia are alphabetically listed and noted. Sixteen out of the 35 described species are considered valid, i.e. C. gustaviana, C. moltkiana, C. sumatrana, C. tobae and C. tumida from Sumatra; C. javanica, C. pulchella and C. rivalis from Java; C.

  7. 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.

  8. Toxicokinetics of waterborne trivalent arsenic in the freshwater bivalve Corbicula fluminea.

    Science.gov (United States)

    Costa, Pedro M; Santos, Hugo M; Peres, Isabel; Costa, Maria H; Alves, Sheila; Capelo-Martinez, José Luís; Diniz, Mário S

    2009-08-01

    Arsenite (As(III)) uptake and elimination kinetics were studied in a freshwater bivalve, Corbicula fluminea, exposed to several nominal concentrations of As(III) (0, 100, 300, 500, and 1000 microg L(-1)) in a static 28-day assay, followed by a depuration stage of 14 days. At the end of each sampling time (days 0, 7, 28, and 42) whole-body portions were surveyed for total As concentrations and, complimentarily, surveyed for whole-body metallothionein (MT) induction to assess its role as a defense mechanism against exposure to As(III). Histochemical evaluation of the digestive gland was performed to verify As deposition and elimination in the tissue. Results show a significant increase in whole-body total As after 28 days of exposure for all treatments, followed by a decrease at the end of the depuration phase. Biodynamic kinetic models for As uptake and elimination were obtained from bioaccumulation data during the exposure phase, for all As treatments, by estimating uptake and elimination rate constants. Bioconcentration factors (BCFs) were estimated by the ratio of these constants. Results revealed that exposure to higher concentrations of As(III) causes a decrease in BCFs, suggesting that C. fluminea triggers effective regulatory mechanisms when exposed to higher concentrations of the metalloid. Significant induction of MT was detected during the exposure phase, followed by a decrease in MT concentration to control levels after depuration for all treatments. No significant differences in MT concentrations were observed between treatments. This finding may confirm the role of MT as part of the As regulation process, but its independence relative to concentrations of As(III) in water suggests that MT induction is not dose dependent. The histochemical evaluation provided clear evidence that As was effectively accumulated in the digestive gland during exposure and eliminated during depuration. The present work demonstrated that C. fluminea is capable of regulating As

  9. 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.

  10. Using enriched stable isotope technique to study Cu bioaccumulation and bioavailability in Corbicula fluminea from Taihu Lake, China.

    Science.gov (United States)

    Fan, Wenhong; Ren, Jinqian; Wu, Chenguang; Tan, Cheng; Wang, Xiaolong; Cui, Minming; Wu, Kuang; Li, Xiaomin

    2014-12-01

    In this study, we measured trace metals (Cd, Cr, Cu, Ni, Pb, and Zn) in water and sediment from representative sites of Taihu Lake, with focus on the analysis of trace metal accumulation in Corbicula fluminea (bivalve). The results showed that the quality of water in Taihu Lake was generally good and the correlation was not found between Cu bioaccumulation in C. fluminea and the concentration in water and sediment. Thus, using the stable isotope tracer method, we studied Cu uptake from the water phase, the assimilation of Cu from the food phase, and the efflux of Cu in vivo by C. fluminea. The result revealed that this species exhibited a relatively lower efflux rate constant of Cu compared with other zoobenthos species. Using a simple bioenergetics-based kinetic model, Cu concentrations in the C. fluminea were calculated with the measured efflux rate. We put forward a novel method, which was taking the influence of biological kinetic on metal bioaccumulation into account to explain the field survey data.

  11. 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

  12. Modelling the risk of mortality of Corbicula fluminea (Müller, 1774 (Bivalvia: Corbiculidae exposed to different turbidity conditions

    Directory of Open Access Journals (Sweden)

    WEP. Avelar

    Full Text Available The provision of sediment in rivers, due to erosion processes that occur in the environment, consists of a major source of pollution and alteration of the physicochemical conditions of water resources. In addition, the increase in water turbidity may cause siltation, dramatically impacting aquatic communities. Specifically considering the bivalve Corbicula fluminea (Müller, 1774, the aim of this study was to analyse the effect of exposure to different turbidity conditions of sediments, as a risk factor for the animals. For this purpose, a docking device was designed to ensure water circulation in a closed system and to maintain the desired levels of turbidity. Although C. fluminea can generally tolerate environmental changes in aquatic systems, an intolerance to high turbidity levels was experimentally observed, expressed by the mortality rate of the animals when exposed to conditions above 150 nephelometric turbidity units (NTU. This value was similar to the one recorded at study sites in the rivers Pardo (Serrana-SP-Brazil and Mogi Guaçu (Porto Ferreira-SP-Brazil during the rainy season. Using a logistic regression model, the experimental results were analysed and the observed mortality rates indicate that the exposure of the animals to turbidity levels above 150 nephelometric turbidity units (NTU, for periods longer than 120 hours, may be considered a probable cause of mortality for the species.

  13. Modelling the risk of mortality of Corbicula fluminea (Müller, 1774) (Bivalvia: Corbiculidae) exposed to different turbidity conditions.

    Science.gov (United States)

    Avelar, W E P; Neves, F F; Lavrador, M A S

    2014-05-01

    The provision of sediment in rivers, due to erosion processes that occur in the environment, consists of a major source of pollution and alteration of the physicochemical conditions of water resources. In addition, the increase in water turbidity may cause siltation, dramatically impacting aquatic communities. Specifically considering the bivalve Corbicula fluminea (Müller, 1774), the aim of this study was to analyse the effect of exposure to different turbidity conditions of sediments, as a risk factor for the animals. For this purpose, a docking device was designed to ensure water circulation in a closed system and to maintain the desired levels of turbidity. Although C. fluminea can generally tolerate environmental changes in aquatic systems, an intolerance to high turbidity levels was experimentally observed, expressed by the mortality rate of the animals when exposed to conditions above 150 nephelometric turbidity units (NTU). This value was similar to the one recorded at study sites in the rivers Pardo (Serrana-SP-Brazil) and Mogi Guaçu (Porto Ferreira-SP-Brazil) during the rainy season. Using a logistic regression model, the experimental results were analysed and the observed mortality rates indicate that the exposure of the animals to turbidity levels above 150 nephelometric turbidity units (NTU), for periods longer than 120 hours, may be considered a probable cause of mortality for the species.

  14. Fate of redspotted grouper nervous necrosis virus (RGNNV) in experimentally challenged Manila clam Ruditapes philippinarum.

    Science.gov (United States)

    Volpe, E; Pagnini, N; Serratore, P; Ciulli, S

    2017-06-19

    Redspotted grouper nervous necrosis virus (RGNNV), genus Betanodavirus, family Nodaviridae, is the causative agent of viral encephalopathy and retinopathy (otherwise known as viral nervous necrosis) and can infect several fish species worldwide. Betanodaviruses, including RGNNV, are very resilient in the aquatic environment, and their presence has already been reported in several wild marine species including invertebrates. In order to investigate the interaction between a bivalve mollusc (Manila clam Ruditapes philippinarum) and RGNNV, we optimised a culture-based method. The bioaccumulation of the pathogenic RGNNV by R. philippinarum and the potential shedding of viable RGNNV from RGNNV-exposed clams were evaluated through a culture-based method. R. philippinarum clearly accumulated viable RGNNV in their hepatopancreatic tissue and were able to release viable RGNNV via faecal matter and filtered water into the surrounding environment. The role of clams as bioaccumulators and shedders of viable RGGNV could put susceptible cohabiting cultured fish at risk. RGNNV-contaminated molluscs could behave as reservoirs for this virus and may modify the virus epidemiology.

  15. Mechanisms of cadmium accumulation (adsorption and absorption) by the freshwater bivalve Corbicula fluminea under hydrodynamic conditions.

    Science.gov (United States)

    Nan, Geng; Peifang, Wang; Chao, Wang; Jun, Hou; Jin, Qian; Lingzhan, Miao

    2016-05-01

    Many heavy metals in sediments and water have potential adverse effects on aquatic organisms such as Corbicula fluminea (O.F. Müller, 1774), a bivalve species frequently used as a biomonitor for metal pollution. Studies over the past decades examining the heavy metal uptake by C. fluminea, very few has investigated the effect of hydrodynamic conditions on accumulation of heavy metal by C. fluminea. Therefore, in this study, to investigate the mechanism of intracellular and extracellular accumulation of metal, individuals of C. fluminea were exposed to cadmium (Cd)-treated water under three different hydrodynamic conditions. These included exposures in two set ups: three rates of rotation (500, 350, 200 r/min) in beakers for 10 days, and then exposure to Cd-treated sediment under two naturally turbulent water conditions (14 cm/s and 3.2 cm/s) in experimental flumes for 23 days. Hydrodynamic force increased the burrowing rate but decreased the activity of C. fluminea. After 10 days of exposure, the extracellular concentrations of Cd in the tissues of C. fluminea in the sand group were significantly higher than that in the gravel groups. The intracellular and extracellular concentrations of Cd in the tissues of C. fluminea dramatically increased in the Cd-treated sediment test. Moreover, the concentration of the extracellular Cd adsorbed on the tissues of C. fluminea in the 14 cm/s and 3.2 cm/s groups was significantly higher than that in the control group, whereas the effect of hydrodynamic force on absorption of Cd by C. fluminea was not obvious. These results suggest that hydrodynamic condition plays an important role in extracellular accumulation of Cd by C. fluminea. In future study, when using C. fluminea to assess Cd pollution in aquatic environment, extracellular Cd adsorbed on the tissue should be removed to avoid the influence of hydrodynamics. Copyright © 2016. Published by Elsevier Ltd.

  16. Clam predator protection is effective and necessary for food production.

    Science.gov (United States)

    Munroe, Daphne; Kraeuter, John; Beal, Brian; Chew, Ken; Luckenbach, Mark; Peterson, Charles P

    2015-11-15

    Shellfish aquaculture is a widely practiced way of producing food for human consumption in coastal areas. When farming intertidal clams, farmers commonly protect young seedling clams from predatory losses by covering farmed plots with netting or screening. Recent discussion of the effectiveness of protective nets or screens and their environmental effects has raised questions concerning the utility of the practice. We provide data based on a review of more than 35 peer-reviewed articles, as well as our own research that demonstrates the efficacy of predator protection for clam farms in various habitats around the world. In addition, we evaluate the effects of screening on temperature, and comment on ancient practices of clam gardening as conducted in the Pacific Northwest. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Effects of copper exposure on the energy metabolism in juveniles of the marine clam Mesodesma mactroides.

    Science.gov (United States)

    Giacomin, Marina; Jorge, Marianna Basso; Bianchini, Adalto

    2014-07-01

    In freshwater osmoregulating mollusks, Cu can cause toxicity by inducing ionoregulatory disturbances. In mussels, it inhibits the activity of key enzymes involved in Na(+) uptake and consequently induces ionic and osmotic disturbances. In snails, Cu induces disruption of the Ca(2+) homeostasis leading to effects in shell deposition and snail growth. However, the mechanisms involved in Cu toxicity in osmoconforming sweater mollusks remain unclear. Recent findings from our laboratory have suggested that Cu toxicity in marine invertebrates can be associated with both ionic and respiratory disturbances. In the present study, metabolic changes induced by waterborne Cu exposure were evaluated in the osmoconforming clam Mesodesma mactroides, a bivalve species widely distributed along the South American sandy beaches. Juvenile clams were kept under control conditions (no Cu addition in the water) or acutely (96h) exposed to Cu (96-h LC10=150μgL(-1)) in artificial seawater (30ppt). ATP, protein, lipid, glycogen and glucose contents were analyzed in gills, digestive gland, pedal muscle and hemolymph. Dinucleotide (NAD(+) and NADH) content was also analyzed in gills, digestive gland and pedal muscle while pyruvate and lactate content was determined in pedal muscle and hemolymph. In all tissues analyzed, Cu exposure did not affect ATP content and NAD(+)/NADH ratio, except in the hemolymph, where a decrease in ATP content was observed. These findings indicate that clam cells, except those from hemolymph, were able to maintain a constant level of free energy. A significant increase in total protein content was observed in the digestive gland, which could be a compensatory mechanism to counteract the higher level of protein oxidation previously observed in M. mactroides exposed to Cu under the same experimental conditions. Finally, reduced glucose content in the pedal muscle paralleled by increased lactate content in the pedal muscle and hemolymph was observed in Cu

  18. 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.

  19. 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.

  20. Yes, caffeine, ibuprofen, carbamazepine, novobiocin and tamoxifen have an effect on Corbicula fluminea (Müller, 1774).

    Science.gov (United States)

    Aguirre-Martínez, Gabriela V; DelValls, Angel T; Laura Martín-Díaz, M

    2015-10-01

    Reports indicating the presence of pharmaceutical in fresh water environment in the ngL(-1) to µgL(-1) range are occurring with increasing frequency. It is also a fact that pharmaceuticals may produce adverse effects on aquatic organisms. Nevertheless, there is still a lack of knowledge regarding how these emergent contaminants may affect aquatic biota. The goal of this research was to evaluate the sublethal responses in Corbicula fluminea such as, general stress (lysosomal membrane stability [LMS]), biomarkers of phase I and II (etoxyresorufin O-deethylase [EROD], dibenzylfluorescein dealkylase [DBF], gluthathione-S-transferase [GST]), oxidative stress (gluthathione reductase [GR], gluthathione peroxidase [GPX], lipid peroxidation [LPO]), and biomarkers of effect (DNA damage) after 21 days of exposure to caffeine, ibuprofen, carbamazepine, novobiocin and tamoxifen at 0.1, 1, 5, 10, 15, 50µgL(-1). Environmental concentrations tested in this study caused general stress and produced changes on biomarkers tested. LMS, responses from phase I and II enzymatic activity, oxidative stress, and biomarker of effect represent important ecotoxicological information, and will provide a useful reference for the assessment of selected drugs and the effects which these compounds may have on aquatic invertebrates, using C. fluminea as a bioindicator species. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. An experimental approach to assess Corbicula fluminea (Müller, 1774) resistance to osmotic stress in estuarine habitats

    Science.gov (United States)

    Ferreira-Rodríguez, Noé; Pardo, Isabel

    2016-07-01

    Corbicula fluminea arrived in the Miño Estuary in 1989 and, from there, colonized more than 150 km upstream. Our aim was to test the capacity of C. fluminea to cope with osmotic stress conditions previously to invade new freshwater habitats through estuaries. Based on previously collected information, the experiment aims to study the response of the species to marine osmotic stress, evaluated by survival and behaviour. Experiments determined the resistance by the species to various levels of osmotic stress, and recovery time after exposure to high salinity levels, representative of the temporal and spatial salinity variation existing in the estuary. Under osmotic stress the semi-maximum response was reached after 19 days exposure. The species tolerance range, measured by individual maintained activity, was at salinity ∼20 when exposed to winter temperatures, while when animals were exposed to summer ones its tolerance was reduced to salinity lower than 15. C. fluminea show a large physiological flexibility to cope with salinity variations in estuaries. In summer, the temperature increases the metabolic rate thus making the species more vulnerable to osmotic stress exposure. These findings are relevant to preventing new invasions through ship ballast waters ensuring complete mortality if individuals are retained for >26 days.

  2. CLAMS ER-2 Moderate Resolution Imaging Spectrometer (MODIS) Airborne Simulator (MAS)

    Data.gov (United States)

    National Aeronautics and Space Administration — CLAMS_ER2_MAS data were collected during the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment with the objective to combine long...

  3. Ecotoxicity of the antihistaminic drug cetirizine to Ruditapes philippinarum clams.

    Science.gov (United States)

    Almeida, Ângela; Calisto, Vânia; Esteves, Valdemar I; Schneider, Rudolf J; Soares, Amadeu M V M; Figueira, Etelvina; Freitas, Rosa

    2017-12-01

    Cetirizine (CTZ) is an antihistaminic drug present in the aquatic environment, with limited information on its toxicity to organisms inhabiting this system. This study intended to evaluate the effects of CTZ on oxidative stress and energy metabolism biomarkers in the edible clam Ruditapes philippinarum after a 28days exposure to environmentally relevant CTZ concentrations (0.0, 0.3, 3.0, 6.0 and 12.0μg/L). The results obtained showed that CTZ was accumulated by clams reaching maximum concentrations (up to ~22ng/g FW) at the highest CTZ exposure concentrations (6.0 and 12.0μg/L). The bioconcentration factor (average maximum values of ~5) decreased at 12.0μg/L reflecting a reduction in clams uptake or increase of excretion capacity at this condition. The present study revealed that, in general, clams decreased the metabolic potential after exposure to CTZ (decrease in electron transport system activity), a response that led to the maintenance of glycogen content in organisms exposed to CTZ in comparison to control values. Our findings also showed that, CTZ did not exert significant levels of oxidative injury to clams. However, comparing the control with the highest exposure concentrations (6.0 and 12.0μg/L) a significant increase of the antioxidant enzyme superoxide activity (~53 and ~44%) was observed in clams exposed to CTZ. Moreover, a tendency to increase lipid peroxidation (~14 and ~9%) and carbonyl groups on proteins (~11 and ~3%) was observed in clams exposed to CTZ (6.0 and 12.0μg/L) compared to control condition. Overall the present study suggests that toxic impacts may be induced in R. philippinarum if exposed for longer periods or higher CTZ concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

  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.

  5. 40 CFR 408.240 - Applicability; description of the mechanized clam processing subcategory.

    Science.gov (United States)

    2010-07-01

    ... mechanized clam processing subcategory. 408.240 Section 408.240 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Mechanized Clam Processing Subcategory § 408.240 Applicability; description of the mechanized clam processing subcategory. The provisions of this subpart are applicable to discharges resulting...

  6. 40 CFR 408.230 - Applicability; description of the hand-shucked clam processing subcategory.

    Science.gov (United States)

    2010-07-01

    ...-shucked clam processing subcategory. 408.230 Section 408.230 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Hand-Shucked Clam Processing Subcategory § 408.230 Applicability; description of the hand-shucked clam processing subcategory. The provisions of this subpart are applicable to discharges resulting...

  7. Conditions for Barrel and Clam-Shell Liquid Drops to Move on Bio-inspired Conical Wires.

    Science.gov (United States)

    Luo, Cheng; Wang, Xiang

    2017-08-29

    It has been reported that, in a foggy environment, water drops with either barrel or clam-shell shapes are capable of self-running on conical wire-like structures, such as cactus spines, spider silk, and water striders' legs. On the other hand, the corresponding moving mechanisms are still not quite understood. For instance, it is unclear under what conditions clam-shell drops would move from the tip towards the root on a conical wire. In this work, based on the balance of forces, we derive conditions for a drop to self-transport towards or away from the root. We find that, although barrel and clam-shell drops have different shapes, these conditions are applicable to both of them, which thus provide good guidelines for developing artificial fog collectors. Furthermore, based on the derived conditions, we interpret drop movements on both hydrophilic and hydrophobic wires, with the support of experimental results on cactus spines. Finally, our results indicate that not all the cacti are able to harvest water from fog.

  8. An efficient method of noroviruses recovery from oysters and clams

    Science.gov (United States)

    Zhou, Deqing; Ma, Liping; Zhao, Feng; Yao, Lin; Su, Laijin; Li, Xinguang

    2013-03-01

    Noroviruses (NoVs) are widespread causes of nonbacterial gastroenteritis. Outbreaks of NoVs caused diseases are commonly ascribed to the consumption of contaminated shellfish. The concentration and RNA extraction of NoVs are crucial steps of detecting NoVs in shellfish. This study aimed to select a simple, rapid and highly efficient recovery method of NoVs detection with real-time RT-PCR. Four methods of recovering GI.3 and GII.4 NoVs from spiked digestive tissues of oysters and clams, respectively, were compared, of them, the method involving proteinase K and PEG 8000 was found the most efficient. With this method, 9.3% and 13.1% of GI.3 and GII.4 NoVs were recovered from oysters and 9.6% and 12.3% of GI.3 and GII.4 NoVs were recovered from clams, respectively. This method was further used to detect NoVs in 84 oysters ( Crassostrea gigas) and 86 clams ( Ruditapes philippinarum) collected from 10 coastal cities in China from Jan. 2011 to Feb. 2012. The NoVs isolation rates were 10.47% of clams (9/86) and 7.14% of oysters (6/84). All the detected NoVs belonged to genotype GII. The NoVs recovery method selected is efficient for NoVs detection in oysters and clams.

  9. Status and improvement of CLAM for nuclear application

    Science.gov (United States)

    Huang, Qunying

    2017-08-01

    A program for China low activation martensitic steel (CLAM) development has been underway since 2001 to satisfy the material requirements of the test blanket module (TBM) for ITER, China fusion engineering test reactor and China fusion demonstration reactor. It has been undertaken by the Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences under wide domestic and international collaborations. Extensive work and efforts are being devoted to the R&D of CLAM, such as mechanical property evaluation before and after neutron irradiation, fabrication of scaled TBM by welding and additive manufacturing, improvement of its irradiation resistance as well as high temperature properties by precipitate strengthening to achieve its final successful application in fusion systems. The status and improvement of CLAM are introduced in this paper.

  10. Microstructure evolution of CLAM steel during creep at 923K

    Science.gov (United States)

    Ye, S.; Zhao, F.; Huang, F.; He, J.; Wang, J. L.

    2017-08-01

    The microstructure change of CLAM steel during creep testing process was investigated at the temperature of 923K with different stress. The results show that the fragmentation and polygonization of martensite lath, as well as the degeneration of dislocation structure are the main factors to deteriorate the creep performance. The stability of MX precipitates in CLAM steel during high temperature creep is good, but the amount and size of M23C6 precipitates are increased. The Laves phase was not found in all samples, which may be due to the experimental temperature is close to the dissolution temperature of Laves phase. The higher temperature accelerates the microstructure evolution of CLAM steel, which results in the degradation of creep properties.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. Kinetic analysis of uranium accumulation in the bivalve Corbicula fluminea: effect of pH and direct exposure levels

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Olivier; Garnier-Laplace, Jacqueline

    2004-06-10

    The bioaccumulation of natural uranium in the freshwater bivalve Corbicula fluminea was investigated subsequent to the bivalve's experimental waterborne exposures. A first experiment determined the accumulation rate (transfer efficiency, tissular distribution) and subcellular distribution of uranium in organs after over 42 days of uranium exposure (100 {mu}g l{sup -1}; pH 7) and later following 60 days of depuration. Results showed that there was direct transfer of uranium to the bivalve organs ([U]{sub organism}/[U]{sub water} = 0.16, fresh weight, fw). The highest accumulation levels occurred in the visceral mass and remained constant throughout the exposure duration, although a linear increase in the U concentration in the gills was observed (2.98{+-}1.3-10.9{+-}3.7 {mu}g g{sup -1} between Days 2 and 42). A second set of experiments were performed in order to test the influence of the exposure levels (100; 500; 1500 {mu}g l{sup -1}) and pH (7 and 8.1) on the bioaccumulation capacities. A marked difference of U distribution is observed as a function of exposure levels (gills were favoured in the case of high exposure levels-relative burden: 49.1{+-}3% (1500 {mu}g l{sup -1}), whereas the visceral mass presented higher accumulation levels at environmentally relevant U concentrations). Uranium concentration in the insoluble fraction (80%) in the whole body does not depend upon exposure levels in the water column or upon duration. These experiments did not allow any link to be established between the free-metal ion concentration and the bioaccumulation efficiency. Results showed a significant pH effect and indicated a link between the exposure conditions and the distribution of uranium in the bivalve organs.

  16. Effect of Surface Preparation on CLAM/CLAM Hot Isostatic Pressing diffusion bonding joints

    Science.gov (United States)

    Li, C.; Huang, Q.; Zhang, P.

    2009-04-01

    Surface preparation is essential for the Hot Isostatic Pressing (HIP) diffusion bonding of RAFM steels. Hot Isostatic Pressing (HIP) diffusion bonding experiments on China Low Activation Martensitic (CLAM) steel was performed to study the effect of surface preparation. A few approaches such as hand lapping, dry-milling and grinding etc., were used to prepare the faying surfaces of the HIP joints. Different sealing techniques were used as well. The HIP parameters were 150 MPa/3 h/1150 °C. After post HIP heat treatment (PHHT), the tensile and Charpy impact tests were carried out. The results showed that hand lapping was not suitable to prepare the faying surfaces of HIP diffusion bonding specimens although the surface roughness by hand lapping was very low.

  17. Rapid evolution of sessility in an endemic species flock of the freshwater bivalve Corbicula from ancient lakes on Sulawesi, Indonesia.

    Science.gov (United States)

    von Rintelen, Thomas; Glaubrecht, Matthias

    2006-03-22

    The fauna of ancient lakes frequently contains taxa with highly derived morphologies that resulted from in situ radiation of lacustrine lineages with high antiquity. We employed a molecular mtDNA phylogeny to investigate this claim for corbiculid freshwater bivalves in two ancient lake systems on the Indonesian island Sulawesi. Among the otherwise mobile corbiculid species flock, only one taxon, Posostrea anomioides, in the ancient Lake Poso exhibits a unique habit, i.e. cementing one valve to the substrate. Our data show that Corbicula on Sulawesi is polyphyletic, with the endemic riverine taxa in terminal position, and the lacustrine species flock being paraphyletic. Surprisingly, Posostrea is not confirmed as a genus distinct from Corbicula and genetic distances suggest a rather recent origin from the only other corbiculid species endemic to Lake Poso, the non-cementing Corbicula possoensis. While the cementing anomioides, despite its unique behavioural and morphological characteristics, clusters together with non-sessile Corbicula species, the latter exhibit strong genetic distances in the absence of morphological disparity and fall into several genetically rather distinct clades. These findings suggest that developmental plasticity of animals in ancient lakes rather than the antiquity of lineages might account for the unique morphology of some species.

  18. Endocrine-disrupting chemicals in coastal lagoons of the Po River delta: sediment contamination, bioaccumulation and effects on Manila clams.

    Science.gov (United States)

    Casatta, Nadia; Stefani, Fabrizio; Pozzoni, Fiorenzo; Guzzella, Licia; Marziali, Laura; Mascolo, Giuseppe; Viganò, Luigi

    2016-06-01

    The large estuary that the River Po forms at its confluence into the Adriatic Sea comprises a multitude of transitional environments, including coastal lagoons. This complex system receives the nutrients transported by the River Po but also its load of chemical contaminants, which may pose a substantial (eco)toxicological risk. Despite the high ecological and economic importance of these vulnerable environments, there is a substantial lack of information on this risk. In light of the recent amendments of the European Water Framework Directive (2013/39/EU), the present study investigated the sediment contamination of six coastal lagoons of the Po delta and its effects on Manila clams (Ruditapes philippinarum), exposed in situ for 3 months. Sediment contamination and clam bioaccumulation of a wide range of chemicals, i.e. trace metals (Cd, Cr, Ni, Hg, Pb, As), polybrominated diphenyl ethers (PBDEs), alkylphenols (APs), organochlorine compounds (PCBs, DDTs), polycyclic aromatic hydrocarbons (PAHs) and organotins (TPhT, TBT), suggested a southward increase related to the riverine transports. Where the River Po influence was more direct, the concentrations of contaminants were higher, with nonylphenol and BDE-209 exceeding sediment quality guidelines. Biometric indicators suggested the influence of contamination on organism health; an inverse relationship between PBDEs in sediments and clam condition index has been found, as well as different biota-sediment accumulation factors (BSAFs) in the lagoons.

  19. Measurement and analysis of SHCCT diagram for CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Huang Yuming [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Chen Xizhang, E-mail: kernel.chen@gmail.com [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Shen Zheng [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Madigan, Bruce [Montana Tech. of University of Montana, Butte, MT 59701 (United States); Yucheng, Lei [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Zhou Jianzhong [School of Mechanical Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China)

    2013-01-15

    China Low Activation Martensitic (CLAM) steel is a leading candidate material for construction of the Chinese fusion reactor Test Blanket Module. The Simulated HAZ Continuous Cooling Transformation (SHCCT) diagram is developed via physical simulation, and the effects of thermal history on the microstructure and mechanical properties of the weld coarse-grain heat-affected zone (CGHAZ) in CLAM steel are evaluated. The results of thermal cycle simulation show that grain size increases and hardness decreases gradually with increasing heat input. Under certain conditions, especially when cooling times from 800 Degree-Sign C to 500 Degree-Sign C (T8/5) are larger than 136 s, delta ferrite may form which is deleterious for the TBM application. The amounts of delta ferrite are given under different T8/5. A SHCCT diagram of CLAM steel is developed using dilatometry and it predicts the AC1, AC3 and the Ms temperatures. With decreased cooling rate (larger T8/5), martensite laths widen and carbide precipitates grow. The results indicate that welding heat input should be taken into consideration and controlled in practical CLAM steel welding process applications.

  20. Characterisation of the secretome of the clam parasite, QPX.

    Science.gov (United States)

    Rubin, Ewelina; Pales Espinosa, Emmanuelle; Koller, Antonius; Allam, Bassem

    2015-02-01

    Secreted and cell surface-associated molecules play a major role in disease development processes and host-pathogen interactions, and usually determine the virulence of invading organisms. In this study, we investigated proteins secreted by quahog parasite unknown, a thraustochytrid protist that infects the hard clam, Mercenaria mercenaria. In silico analysis of quahog parasite unknown transcripts predicted over 1200 proteins to possess an amino-terminal signal peptide which directs proteins into the classical eukaryotic secretory pathway. Proteomic analysis using LC/MS technology identified 56 proteins present in the extracellular secretion of quahog parasite unknown cells grown in vitro, including six mucin-like molecules, four glycosyl hydrolases and eight peptidases. Transcription levels of 19 quahog parasite unknown extracellular proteins were investigated in clam tissue lesions (in vivo) using quantitative PCR. The overexpression of six of these extracellular proteins in clam tissues compared with in vitro cultures suggests that they are involved in interaction with the clam host. Copyright © 2014 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  1. Development status of CLAM steel for fusion application

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qunying, E-mail: qunying.huang@fds.org.cn

    2014-12-15

    The China low activation martensitic (CLAM) steel is being developed at the Institute of Nuclear Energy Safety Technology (INEST) under wide collaboration within China. Significant R and D work on CLAM steel was carried out to help make it suitable for industrial applications. The effect of refining processes and thermal aging on composition, microstructures and mechanical properties were investigated. Material properties before irradiation including impact, fracture toughness, thermal aging, creep and fatigue properties etc. were assessed. A series of irradiation tests in the fission reactor HFETR in Chengdu up to 2 dpa and in the spallation neutron source SINQ in Paul Scherrer Institute up to 20 dpa were performed. PbLi corrosion tests for more than 10,000 h were done in the DRAGON-I and PICOLO loops. Fabrication techniques for a test blanket module (TBM) are being developed and a 1/3 scale TBM prototype is being fabricated with CLAM steel. Recent progresses on the development status of this steel are presented here. The code qualification of CLAM steel is under plan for its final application in ITER-TBM and DEMO in the future.

  2. Comanagement of clams in Brazil: a framework to advance comparison

    Directory of Open Access Journals (Sweden)

    Ligia M. Rocha

    2015-03-01

    Full Text Available In Brazil, the recognition that fisheries encompass both natural ecosystems and human well-being has increased, but initiatives are focused largely on highly-valued species, ignoring socially relevant resources such as Venus clams (Anomalocardia brasiliana. We investigate two initiatives involving comanagement of Venus clams in the past two decades: the Marine Extractive Reserve "Pirajubaé" and the "People of the Tides" project. We focus on the nature of the institutional arrangements, the involved groups (fishing communities and government, and the resource, as well as the steps involved in developing the partnerships, identifying which factors favor success in comanagement. Through these projects, fisherwomen got visibility and clam harvesters became the center of institutional developments. However, their rights in management will not become meaningful unless comanagement in protected areas is fully implemented, and government becomes more willing to share power in harvest planning, and to improve health, infrastructure, and the return of value to fisher families. Only then would such cooperation promote sustainability for Venus clams and fisher families.

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

    African Journals Online (AJOL)

    The aim of this study was to obtain protein extracts from the clam Chione fluctifraga and determine its antiproliferative activity against cervical and breast cancer cells. The extracts were obtained by ammonium sulfate fractionation, gel filtration and ion exchange chromatography. Antiproliferative activity was evaluated by 3-(4 ...

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

    Science.gov (United States)

    Kang, Hee Yoon; Lee, Young-Jae; Choi, Kwang-Sik; Park, Hyun Je; Yun, Sung-Gyu; Kang, Chang-Keun

    2016-01-01

    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 wide variety

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

    Science.gov (United States)

    Kang, Hee Yoon; Lee, Young-Jae; Choi, Kwang-Sik; Park, Hyun Je; Yun, Sung-Gyu; Kang, Chang-Keun

    2016-01-01

    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 wide

  6. 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

  7. Kinetics of phosphorus release from sediments and its relationship with iron speciation influenced by the mussel (Corbicula fluminea) bioturbation.

    Science.gov (United States)

    Chen, Musong; Ding, Shiming; Liu, Ling; Xu, Di; Gong, Mengdan; Tang, Hao; Zhang, Chaosheng

    2016-01-15

    The effects of bivalve (Corbicula fluminea) bioturbation on the lability of phosphorus (P) in sediments were investigated. The high-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) techniques were employed to obtain soluble and labile P/Fe profiles at a vertical resolution of 2 and 1mm, respectively. The bivalve bioturbation increased the concentrations of soluble reactive P (SRP) in pore water and DGT-labile P up to 116% and 833% of the control within the sediment depths from the sediment water interface (SWI) to -64 mm and -44 mm, respectively. The sediments with bioturbation had a smaller distribution coefficient than the control (1964 vs. 3010 cm(3) g(-1)), reflecting a weaker ability in retaining P. Meanwhile, the sediments with bioturbation had a greater ratio of the concentration of DGT-labile P to that of SRP (0.20 vs. 0.03), demonstrating a stronger ability to resupply pore water SRP by the sediment solids when they are affected by the bioturbation. The DGT-induced fluxes in sediments (DIFS) modeling further showed a much shorter response time (277.9 vs. 18,670 s) and a much higher rate (0.192 vs. 0.002 day(-1)) of the solids in release of P with the bioturbation. Correspondingly, the flux of P to the overlying water from the bioturbation treatment increased up to 157% of the control. The bivalve bioturbation significantly increased the concentrations of soluble Fe(II) and DGT-labile Fe up to 84% and 334% of the control from the SWI to -46 mm, respectively. The SRP and DGT-labile P were highly correlated with respective soluble and DGT-labile Fe. It was concluded that the release of P from the sediments with bioturbation to the pore water and the overlying water was promoted by the reductive dissolution of easily reducible Fe(oxyhydr)oxides due to the depletion of oxygen in the top sediments from bivalve respiration. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. 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

  9. A light-dependent ammonia-assimilating mechanism in the ctenidia of a giant clam

    Science.gov (United States)

    Hiong, Kum C.; Choo, Celine Y. L.; Boo, Mel V.; Ching, Biyun; Wong, Wai P.; Chew, Shit F.; Ip, Yuen K.

    2017-03-01

    Giant clams harbor symbiotic zooxanthellae and manifest light-enhanced calcification. In light, they also increase the absorption and assimilation of exogenous ammonia, but the roles of the host and symbionts are unclear and the reason for light dependency remains enigmatic. Here, we report the complete coding cDNA sequence of a glutamine synthetase (GS), from the ctenidia (gill) of Tridacna squamosa. The deduced GS amino acid sequence was closely related to other animal GSs, indicating a host origin. The GS/GS transcript level and protein abundance increased significantly in the ctenidia after 12 h of light exposure. These results denote the ctenidia as the site of light-enhanced ammonia absorption with the absorbed ammonia being assimilated to glutamine by the host GS. Immunofluorescence microscopy confirmed that GS was expressed predominantly in the cytoplasm of the epithelial cells separating the tertiary water channels from the hemolymph inside the ctenidia. Hence, unlike symbiotic cnidarians, the host clam probably supplies exogenous nitrogen as glutamine from the ctenidia, through the hemolymph and tubular fluid, to the nitrogen-deficient zooxanthellae which reside extracellularly in the extensible outer mantle. This is the first report on light-dependent gene and protein expression of a host enzyme involved in nitrogen metabolism in an alga-invertebrate association.

  10. Growth, Survival and Reproduction of the Giant Clam Tridacna maxima (Röding 1798, Bivalvia) in Two Contrasting Lagoons in French Polynesia

    Science.gov (United States)

    Van Wynsberge, Simon; Andréfouët, Serge; Gaertner-Mazouni, Nabila; Wabnitz, Colette C. C.; Menoud, Mathilde; Le Moullac, Gilles; Levy, Peva; Gilbert, Antoine; Remoissenet, Georges

    2017-01-01

    Shell growth, reproduction, and natural mortality of the giant clam Tridacna maxima were characterized over a two-year-period in the lagoon of the high island of Tubuai (Austral Archipelago) and in the semi-closed lagoon of Tatakoto (Tuamotu Archipelago) in French Polynesia. We also recorded temperature, water level, tidal slope, tidal range, and mean wave height in both lagoons. Lower lagoon aperture and exposure to oceanic swells at Tatakoto than at Tubuai was responsible for lower lagoon water renewal, as well as higher variability in temperature and water level at Tatakoto across the studied period. These different environmental conditions had an impact on giant clams. Firstly, spawning events in the lagoon of Tatakoto, detected by gonad maturity indices in June and July 2014, were timed with high oceanic water inflow and a decrease in lagoon water temperature. Secondly, temperature explained differences in shell growth rates between seasons and lagoons, generating different growth curves for the two sites. Thirdly, local mortality rates were also found to likely be related to water renewal patterns. In conclusion, our study suggests that reef aperture and lagoon water renewal rates play an integral role in giant clam life history, with significant differences in rates of shell growth, mortality and fertility found between open versus semi-closed atoll lagoons in coral reef ecosystems. PMID:28118406

  11. Zostera marina seed burial can be enhanced by Manila clam Ruditapes philippinarum: A microcosm study

    Science.gov (United States)

    Li, Chang-Jun; Li, Wen-Tao; Liu, Jianying; Zhang, Xiumei; Zhang, Peidong

    2017-06-01

    Seagrass seed bank plays a key role in the regeneration of new vegetation when seagrasses are removed by the natural or man-made disaster. Various factors may affect the development of sediment seed bank. We conducted a microcosm experiment to test the effects of burrowing and feeding activities of Manila clam, Ruditapes philippinarum on the burial of Zostera marina seeds in sediments. The effects of lasting time (3-hour, 1-day, 3-day, 7-day, 14-day and 28-day), clam density (0, 2, 4 and 8 clams with shell length of 3 cm in each microcosm) and clam size (shell length of 2, 3 and 4 cm at 4-clam density) on seed burial were examined in plastic microcosm cores (30 cm high × 10 in inner diameter) in a 28-day period. Results showed that the seed burial depth significantly increased with time, the density and the size of clams. No seeds were buried in the sediment in the cores without clams during the whole experiment period. For the 3-cm clams, about 91.61% of the seeds were buried in the sediment at the end of the experiment in the high-density treatment (8 clams at each core); while in the medium and low-density treatments (4 and 2 clams in each core, respectively), about 76.93% and 60.61% of the seeds were buried in the sediment, respectively. For the size treatments, large (4 cm) clams buried 89.56% of the seeds at the end of the experiment, much more than those of medium (3 cm, 76.93%) and small (2 cm, 61.50%) size clams. During the whole experiment period, nearly all of the buried seeds were at a depth of from 0 cm to 5 cm. These results suggested that Manila clam Ruditapes philippinarum may play an important positive role in seagrass seed bank dynamics in the field.

  12. Biodiesel Production from Castor Oil by Using Calcium Oxide Derived from Mud Clam Shell

    OpenAIRE

    Ismail, S.; Ahmed, A.S.; Reddy Anr; Hamdan, S

    2016-01-01

    The catalytic potential of calcium oxide synthesized from mud clam shell as a heterogeneous catalyst for biodiesel production was studied. The mud clam shell calcium oxide was characterized using particle size analyzer, Fourier transform infrared spectroscopy, scanning electron microscopy, and BET gas sorption analyzer. The catalyst performance of mud clam shell calcium oxide was studied in the transesterification of castor oil as biodiesel. Catalyst characterization and transesterification s...

  13. 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.

  14. 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.

  15. Domoic acid excretion in dungeness crabs, razor clams and mussels.

    Science.gov (United States)

    Schultz, Irvin R; Skillman, Ann; Woodruff, Dana

    2008-07-01

    Domoic acid (DA) is a neurotoxic amino acid produced by several marine algal species of the Pseudo-nitzschia (PN) genus. We studied the elimination of DA from hemolymph after intravascular (IV) injection in razor clams (Siliqua patula), mussels (Mytilus edulis) and Dungeness crabs (Cancer magister). Crabs were also injected with two other organic acids, dichloroacetic acid (DCAA) and kainic acid (KA). For IV dosing, hemolymph was repetitively sampled and DA concentrations measured by HPLC-UV. Toxicokinetic analysis of DA in crabs suggested most of the injected dose remained within hemolymph compartment with little extravascular distribution. This observation is in sharp contrast to results obtained from clams and mussels which exhibited similarly large apparent volumes of distribution despite large differences in overall clearance. These findings suggest fundamentally different storage and elimination processes are occurring for DA between bivalves and crabs.

  16. Filter-feeding bivalves can remove avian influenza viruses from water and reduce infectivity

    Science.gov (United States)

    Avian influenza (AI) viruses are transmitted within wild aquatic bird populations through an indirect fecal-oral route involving fecal-contaminated water. In this study, the influence of filter-feeding bivalves, Corbicula fluminea, on the infectivity of AI virus in water was examined. A single cla...

  17. The effects of human drugs in Corbicula fluminea. Assessment of neurotoxicity, inflammation, gametogenic activity, and energy status.

    Science.gov (United States)

    Aguirre-Martínez, G V; André, C; Gagné, F; Martín-Díaz, L M

    2018-02-01

    The constant release of pharmaceuticals products to aquatic environment even at low concentrations (ng L -1 to µg L -1 ) could lead to unknown chronic effects to non-target organisms. The aim of this study was to evaluate neurotoxic responses, inflammation, gametogenic activity and energy status on the fresh water clam C. fluminea after exposure to different concentrations of caffeine (CAF), ibuprofen (IBU), carbamazepine (CBZ), novobiocin (NOV) and tamoxifen (TMX) for 21 days under laboratory conditions. During the assay, water was spiked every two days with CAF (0; 0.1; 5; 15; 50µgL -1 ), IBU (0; 0.1; 5; 10; 50µgL -1 ), CBZ, NOV, and TMX (0.1, 1, 10, 50µgL -1 ). After the exposure period, dopamine levels (DOP), monoamine oxidase activity (MAO), arachidonic acid cyclooxygenase activity (COX), vitellogenin-like proteins (VTG), mitochondrial electron transport (MET), total lipids (TLP), and energy expenditure (MET/TLP) were determined in gonad tissues, and acetyl cholinesterase activity (AChE) was determined in digestive gland tissues. Results showed a concentration-dependence response on biomarkers tested, except for MAO. Environmental concentrations of pharmaceuticals induced significant changes (p fluminea constituted a suitable tool for environmental risk assessment of pharmaceutical in aquatic environment. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Electrophoretic separation of gill proteins of the clam Codakia orbicularis.

    Science.gov (United States)

    Gourdine, Jean-Philippe; Smith-Ravin, Emilie J

    2002-11-01

    Marine organisms inhabiting the coastal environment of the Caribbean islands have attracted the attention of a number of research scientists. These organisms generally live in areas of high environmental stress and may, therefore, contain specialized proteins and enzymes which exhibit valuable biotechnological applications. Among them, a small number of clams have been studied. Our work relates to the clam Codakia orbicularis. This bivalve lives in areas of high hydrogen sulfide concentrations on the Caribbean island of Guadeloupe. Its enzymatic system must, therefore, have evolved to allow its adaptation to this high-stress environment. C. orbicularis also contains endosymbiotic bacteria which are housed in the bacteriocytes of the gills. Its protein content can, therefore, be expected to have an impact on this symbiotic relationship. We have analysed gill protein extracts of this clam by various biochemical techniques: SDS-PAGE, IEF, PAS, and Western blotting using a panel of lectins, in order to establish its protein and glycoprotein profiles. This biochemical analysis, the first of its kind, constitutes an important step in separating and characterizing the proteins involved in the biochemical pathways of this organism whose stock is in decline in Guadeloupe. Our results show the presence of three major proteins whose molecular weights vary between 14,000 and 24,000 Daltons, and some of which are glycoproteins with predominantly alpha-mannose and N-acetylgalactosamine moieties. Their pI values are in the range between 4.5 and 5.6. These protein profiles are different from those observed for Lucina pectinata, a clam which has been the subject of earlier studies in the literature.

  19. Brown muscle disease: impact on Manila clam Venerupis (=Ruditapes) philippinarum biology.

    Science.gov (United States)

    Binias, Cindy; Gonzalez, Patrice; Provost, Margot; Lambert, Christophe; de Montaudouin, Xavier

    2014-02-01

    This study assessed the effect of Brown Muscle Disease (BMD) on Manila clam Venerupis philippinarum fitness. BMD was discovered in 2005. It affects the posterior adductor muscle and leads to clam gaping and eventually death. Three statuses of clams were compared: buried individuals with no signs of BMD (BUR); clams at the surface of the sediment with no signs of BMD (SURF) and clams at the surface of the sediment exhibiting signs of brown muscle disease (BMD). Physiological (condition index), immune (hemocyte parameters) and molecular (gene expressions) parameters collected seasonally were analyzed and compared. Results demonstrated a seasonal pattern in condition index (CI) with peaks in spring/summer and decreases in autumn/winter. At each season, the highest CI was observed in BUR and the lowest CI was observed in BMD. In terms of immune response, phagocytosis rate and capacity were higher in clams with BMD whereas the health status of the clams did not influence the total hemocyte count. Genes involved in the immune system (comp, tnf, inter) were upregulated in clams with BMD. The molecular analysis of gill and posterior muscle showed higher mitochondrial metabolism (cox-1, 16S) in cells of infected clams, suggesting a stronger energetic demand by these cells. Finally, genes involved in oxidative stress response (cat, sod), detoxification (mt) and DNA repair (gadd45) were also overexpressed due to reactive oxygen species production. Most of the studied parameters underlined a cause-effect correlation between Manila clam health status (BUR, SUR, BMD) and physiological parameters. An important stress response was observed in BMD-infected clams at different scales, i.e. condition index, immune parameters and stress-related gene expression. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. 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.

  1. Ontogenetic and temperature-dependent changes in tolerance to hypoxia and hydrogen sulfide during the early life stages of the Manila clam Ruditapes philippinarum.

    Science.gov (United States)

    Kodama, Keita; Waku, Mitsuyasu; Sone, Ryota; Miyawaki, Dai; Ishida, Toshiro; Akatsuka, Tetsuji; Horiguchi, Toshihiro

    2018-01-02

    Wind-induced upwelling of hypoxic waters containing hydrogen sulfide (H2S) sometimes causes mass mortalities of aquatic organisms inhabiting coastal areas, including the hypoxia-tolerant Manila clam Ruditapes philippinarum. We examined the tolerance of Manila clam to H2S under controlled laboratory conditions. Larvae and juveniles obtained by artificial fertilization or from a wild population were exposed to normoxic or to hypoxic water with or without un-ionized H2S (concentrations, 0.2-52.2 mg/L). Twenty-four-hour exposure experiments revealed ontogenetic changes in the clam's tolerance to H2S exposure: tolerance was enhanced from the larval stages to juveniles just after settlement but was attenuated as juveniles grew. Tolerance of larvae and juveniles to H2S exposure weakened as the water temperature rose from 20 to 28 °C. Prolonged 48-h exposure to H2S attenuated the tolerance of juveniles to H2S. Temporary suspension of H2S exposure by 24-h reoxygenation improved the ability of juveniles to withstand repeated H2S exposure. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. 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.

  3. 50 CFR 17.45 - Special rules-snails and clams. [Reserved

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 2 2010-10-01 2010-10-01 false Special rules-snails and clams. 17.45 Section 17.45 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—snails and clams. ...

  4. CLAM : Quickly deploy NLP command-line tools on the web

    NARCIS (Netherlands)

    van Gompel, M.; Reynaert, M.W.C.

    2014-01-01

    In this paper we present the software CLAM; the Computational Linguistics Application Mediator. CLAM is a tool that allows you to quickly and transparently transform command-line NLP tools into fully-fledged RESTful webservices with which automated clients can communicate, as well as a generic

  5. Male claspers in clam shrimps (Crustacea, Branchiopoda) in the light of evolution

    DEFF Research Database (Denmark)

    Kaji, Tomonari; Fritsch, Martin; Schwentner, Martin

    2014-01-01

    Male "clam shrimps" possess highly modified first (and second) trunk limbs for clasping the carapace of females during copulation. Claspers are present in all three clam shrimp taxa (Laevicaudata, Spinicaudata, and Cyclestherida) but despite striking similarities in their morphology and function,...

  6. 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 ...

  7. 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 (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 clams.

  8. Production and characterisation of hyaluronidase and elastase inhibitory protein hydrolysates from Venus clam.

    Science.gov (United States)

    Sutthiwanjampa, Chanutchamon; Kim, Sang Moo

    2015-01-01

    The hydrolysates of fresh and boiled Venus clams with five different proteases for the production of low-molecular protein hydrolysates were optimised by response surface methodology. Alcalase hydrolysates exhibited the strongest hyaluronidase inhibitory activity. The optimum hydrolysis conditions of fresh and boiled clams wereclam, and E/S, 2.02%; time, 4.11 h; W/S, 69.74 mL g(-1) for boiled clam. The fresh and boiled clam protein hydrolysates were fractionated by S-200 HR size-exclusion chromatography, which resulted in one (FH1) and two (BH1 and BH2) fractions, respectively. BH1 exhibited the highest hyaluronidase and elastase inhibitory activities with specific activities of 141.15 and 81.36% mL mg(-1), respectively. Therefore, the boiled Venus clam hydrolysate might be developed as a cosmeceutical agent because of its strong hyaluronidase and elastase inhibitory activities.

  9. The Whole-Genome and Transcriptome of the Manila Clam (Ruditapes philippinarum).

    Science.gov (United States)

    Mun, Seyoung; Kim, Yun-Ji; Markkandan, Kesavan; Shin, Wonseok; Oh, Sumin; Woo, Jiyoung; Yoo, Jongsu; An, Hyesuck; Han, Kyudong

    2017-06-01

    The manila clam, Ruditapes philippinarum, is an important bivalve species in worldwide aquaculture including Korea. The aquaculture production of R. philippinarum is under threat from diverse environmental factors including viruses, microorganisms, parasites, and water conditions with subsequently declining production. In spite of its importance as a marine resource, the reference genome of R. philippinarum for comprehensive genetic studies is largely unexplored. Here, we report the de novo whole-genome and transcriptome assembly of R. philippinarum across three different tissues (foot, gill, and adductor muscle), and provide the basic data for advanced studies in selective breeding and disease control in order to obtain successful aquaculture systems. An approximately 2.56 Gb high quality whole-genome was assembled with various library construction methods. A total of 108,034 protein coding gene models were predicted and repetitive elements including simple sequence repeats and noncoding RNAs were identified to further understanding of the genetic background of R. philippinarum for genomics-assisted breeding. Comparative analysis with the bivalve marine invertebrates uncover that the gene family related to complement C1q was enriched. Furthermore, we performed transcriptome analysis with three different tissues in order to support genome annotation and then identified 41,275 transcripts which were annotated. The R. philippinarum genome resource will markedly advance a wide range of potential genetic studies, a reference genome for comparative analysis of bivalve species and unraveling mechanisms of biological processes in molluscs. We believe that the R. philippinarum genome will serve as an initial platform for breeding better-quality clams using a genomic approach. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  10. 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)

  11. Biodeposition, respiration, and excretion rates of an introduced clam Mercenaria mercenaria in ponds with implications for potential competition with the native clam Meretrix meretrix in Shuangtaizi estuary, China

    Science.gov (United States)

    Zhang, Anguo; Yuan, Xiutang; Hou, Wenjiu; Li, Xiaodong; Zhao, Kai; Chen, Weixin; Su, Xiurong

    2016-05-01

    This study aimed to evaluate the potential impacts of an introduced clam Mercenaria mercenaria on estuarine ecosystem, and implications for the niche competition with a native clam Meretrix meretrix. The biodeposition, respiration, and excretion rates of M. mercenaria were determined seasonally using a sediment trap and a closed respirator in field. The biodeposition rates of M. mercenaria were 0.06-0.37 g/ (ind.·d), and the respiration rates were 0.31-14.66 mg/(ind.·d). The ammonia and phosphate excretion rates were 0.18-36.70 and 1.44-14.87 μg/(ind.·d), respectively. The hard clam M. mercenaria may discharge dry deposits up to 2.1×105 t, contribute 18.3 t ammonia and 9.0 t phosphate to culture ponds, and consume 7.9×103 t O2 from ponds annually. It suggested that the hard clam M. mercenaria might play an important role in pelagic-benthic coupling in pond ecosystem through biodeposition and excretion. A comparison of the key physiological parameters of the introduced clam M. mercenaria and the native clam Meretrix meretrix suggested that M. mercenaria had a niche similar to that of Meretrix meretrix in Shuangtaizi estuary and might have a potential competition with Meretrix meretrix for habitat and food if M. mercenaria species escaped from the culture pond or artificially released in estuarine ecosystem.

  12. Environmental Factors Affecting Escherichia coli Concentrations in Striped Venus Clam (Chamelea gallina L.) Harvested in the North Adriatic Sea.

    Science.gov (United States)

    Tabanelli, Giulia; Montanari, Chiara; Gardini, Aldo; Maffei, Mirko; Prioli, Chiara; Gardini, Fausto

    2017-09-01

    The aim of this work was to evaluate the microbiological quality of striped venus clams (Chamelea gallina L.) harvested in the north Adriatic Sea during an 8-year monitoring period. A total of 387 samples were analyzed to assess the presence of Escherichia coli. Environmental parameters (salinity, pH, dissolved oxygen, seawater temperature, and freshwater outflow) were collected to find out a possible relationship between the E. coli counts and environmental factors. The results evidenced that the microbiological quality of the clams was good, with only about 5% of the samples not complying with European and Italian regulations for this product, that is, with E. coli counts higher than 230 most probable number (MPN) per 100 g of flesh and intravalvar liquid. Statistical analyses revealed a relationship between microbial contamination and the season and water temperature, probably due to the difference in the filtering activity of the mollusks. However, the main factor affecting the E. coli concentration in the clams turned out to be the flow rate of Marecchia, the major river that reaches the sea in the area of harvesting. In fact, a model fitted to evaluate the probability of finding a higher E. coli count in relation to the environmental parameters evidenced that it was an increase of the level of the Marecchia led to a higher probability of elevated E. coli contamination. This result could be explained by the higher supply of both nutrients and coliforms (including E. coli) when the river is higher and by the anthropogenic characteristics of the lands crossed by the river.

  13. 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.

  14. Comparative investigations on the biological effects of As (III) and As (V) in clam Ruditapes philippinarum using multiple biomarkers.

    Science.gov (United States)

    Ji, Chenglong; Xu, Hai'e; Wang, Qing; Zhao, Jianmin; Wu, Huifeng

    2015-11-01

    Inorganic arsenic is a known pollutant with two chemical forms, arsenite (As (III)) and arsenate (As (V)), in marine environment. Clam Ruditapes philippinarum is an important fishery species along the Bohai coast. In this study, the biological effects induced by the two arsenic chemical forms (arsenite and arsenate) were compared using multiple biochemical indices in the digestive glands of clam R. philippinarum. The production of reactive oxygen species, antioxidant enzyme activities and metabolic responses exhibited that both As (III) and As (V) induced immune, oxidative and osmotic stresses in clam digestive glands. The differential metabolic biomarkers, histidine and taurine, indicated the differential responsive mechanisms in osmotic regulation in clam digestive glands. In addition, both arsenic treatments enhanced the anaerobiosis metabolism in clam digestive glands. Overall, this work illustrated that arsenite and arsenate induced similar biological effects in clams, which might be accounted for the biological transformation of arsenate to arsenite in clams. Copyright © 2015 Elsevier Ltd. All rights reserved.

  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. Experimental evaluation of the pathogenicity of Perkinsus olseni in juvenile Manila clams Ruditapes philippinarum.

    Science.gov (United States)

    Shimokawa, Jun; Yoshinaga, Tomoyoshi; Ogawa, Kazuo

    2010-11-01

    We evaluated the pathogenicity of Perkinsus olseni towards the Manila clam, Ruditapes philippinarum, by an experimental challenge. For production of prezoosporangia of P. olseni, we injected uninfected Manila clams with cells of a pure strain of P. olseni and reared them for 7d. Prezoosporangia were isolated from the soft tissue of the injected clams after culturing in Ray's fluid thioglycollate medium. Hatchery-reared, uninfected juvenile clams (3-10 mm shell length) were challenged by immersion in one of two concentrations of a prezoosporangial suspension of P. olseni for 6d. The challenged clams had significantly higher mortality at both the concentrations than the unchallenged clams. The mortality due to infection dose-dependently began approximately 4 weeks and 7 weeks after challenge in the higher and lower concentrations, respectively. This is the first experimental evidence that P. olseni causes direct mortality in Manila clams. The lethal level of infection was estimated at approximately 10⁷ pathogen cells/g soft tissue weight. Copyright © 2010 Elsevier Inc. All rights reserved.

  17. 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.

  18. [Case of food protein-induced enterocolitis syndrome caused by short-neck clam ingestion].

    Science.gov (United States)

    Hayashi, Daisuke; Aoki, Takeshi; Shibata, Rumiko; Ichikawa, Kunio

    2010-12-01

    A 6-year-old boy was referred for evaluation because he had several vomiting episodes, from the age of 2 years, following short-neck clam ingestion. He tested negative for short-neck clam-specific IgE just before visiting our hospital, and he was not allergic to other foods or shellfish. The patient had low levels of short-neck clam-specific IgE (1.04 UA/ml), and the skin prick test was positive for short-neck clam (4 mm). The lymphocyte stimulation test was positive (5305 counts per min (cpm), stimulation index (SI) =1211%) and the patch test was positive for short-neck clam ingestion. An oral challenge test with boiled short-neck clam induced abdominal pain and vomiting 2 h after ingestion, and the patient presented with increased peripheral leukocytes after 6 h. He was therefore diagnosed with food protein-induced enterocolitis syndrome (FPIES) due to short-neck clam ingestion. To our knowledge, this is the first case report of FPIES induced by the intake of shellfish.

  19. 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.

  20. Caloric variability of Corbicula fluminea (Mollusca, Bivalvia in Rosana Reservoir, Brazil

    Directory of Open Access Journals (Sweden)

    Yara Moretto Bagatini

    2007-01-01

    Full Text Available The purpose of the present study was to investigate temporal and longitudinal variation of caloric density of Corbicula fluminea in Rosana Reservoir. Significant differences concerning the caloric density of C. fluminea were observed throughout the year at the three reservoir sites. The caloric density variation during the year was probably related to reproductive activity, which demanded higher allocation of energy in certain period. The food source used by this species might be an important factor in the caloric value temporal and spatial variation of C. fluminea in Rosana Reservoir.O objetivo deste estudo foi investigar a variação temporal e longitudinal da densidade calórica de C. fluminea no reservatório de Rosana. Diferenças significativas na densidade calórica de C. fluminea foram observadas ao longo do ano e nas três estações do reservatório. A variação na densidade calórica de C. fluminea, durante o ano, provavelmente foi relacionada à atividade reprodutiva, que exige uma maior alocação de energia em determinado período. O recurso alimentar utilizado por esta espécie pode ser um importante fator na variação temporal e espacial do valor calórico de C. fluminea no reservatório de Rosana.

  1. Nanostructure and crystallography of aberrant columnar vaterite in Corbicula fluminea (Mollusca).

    Science.gov (United States)

    Frenzel, Max; Harrison, Richard J; Harper, Elizabeth M

    2012-04-01

    Both the crystallographic and nanostructural organisation of aberrant columnar vaterite occurring in Corbicula fluminea were characterised in detail for the first time using electron microscopic and X-ray powder diffraction techniques. At the millimetre scale, only a confinement of the otherwise randomly oriented c-axis to the growth surface is observed. Domains of 100 or more individual vaterite columns with common c-axis orientation exist within this disordered material. Each column behaves as a single crystal on the scale of EBSD measurements, but is internally composed of smaller irregularly shaped and slightly misaligned crystalline units (0.3-1.3μm in dimension). These are in turn partitioned by porous boundaries into rounded nanodomains, up to 600nm in size. The geometry of the nanodomains and their respective boundaries might suggest formation by the accretion of vesicles. In addition to crystallographic textures, this observation indicates formation under significant biological control with wider implications for possible causes of the condition. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Comet assay comparison of different Corbicula fluminea (Mollusca tissues for the detection of genotoxicity

    Directory of Open Access Journals (Sweden)

    Janaina Rigonato

    2005-09-01

    Full Text Available The comet assay was used to study the sensitivity of the widely distributed freshwater bivalve mollusk Corbicula fluminea to the DNA-damaging alkylating-agent methylmethane sulfonate (MMS. This study was undertaken to ascertain if C. fluminea is a good bioindicator of pollutants in aquatic environments and identify which C. fluminea tissue is most effective and practical for genotoxicity studies. The mollusks were exposed to 0.6, 1.2 or 2.4 X 10-4 M MMS for 40 min and their hemolymph, gill tissue and digestive gland tissue assessed for the level of DNA damage and the time needed for the tissues to recovery. Regression analysis showed a direct linear dose-response relationship between MMS concentration and the number of damaged cells for hemolymph and digestive gland tissue but a quadratic relationship for gill tissue, which made the interpretation the gill tissue results difficult. The basal level of DNA damage to gill tissue was very high, possibly because gill is the organs most directly exposed to environmental toxins and mutagenic agents. Although all three types of tissue produced useful results, hemolymph and digestive gland tissue produced more reproducible and reliable results. Hemolymph was the best sample type in that it was easy to obtain and handle, while gill tissue required more manipulation to obtain cell suspensions. Our results indicate that C. fluminea is an optimal bioindicator for the determination genotoxic contaminants in aquatic environments.

  3. Gonadal cycle of Corbicula fluminea (Bivalvia: Corbiculidae in Pampean streams (Southern Neotropical Region.

    Directory of Open Access Journals (Sweden)

    Luciana Cao

    Full Text Available Corbicula fluminea is an aggressive invasive species of bivalve that arrived into the Río de la Plata River between the late 60's and early 70's, and dispersed widely throughout the Neotropical region, evidencing a great adaptive flexibility to different environmental conditions. This species is a functional hermaphrodite with larval incubation inside the inner demibranch. Despite its widespread distribution, there are no previous studies of complete gonadal histology and reproductive cycle for this species in the Neotropical region. In this study, the reproductive dynamics of C. fluminea in a temperate region, the Santa Catalina Pampean stream, Argentina, is described. Samples of 20-30 individuals were collected monthly from April 2003-April 2005 and processed using traditional histological techniques. During the two years of this study, seven spawning events were recognized. Three major spawns occurred in spring and summer, and other four minor ones during summer and autumn. Events of oocyte recovery were observed after spawning. A high number of incubating individuals was detected. The results stressed the difficulty of identifying a particular pattern of gamete release and of spawning behaviour in this invasive species, especially when inhabiting an unstable environment.

  4. Three-phase partitioning for efficient extraction and separation of polysaccharides from Corbicula fluminea.

    Science.gov (United States)

    Yan, Jing-Kun; Wang, Yao-Yao; Qiu, Wen-Yi; Shao, Ning

    2017-05-01

    Three-phase partitioning (TPP), which is a simple, efficient, and green bioseparation technique, was used to extract and separate polysaccharides from Corbicula fluminea (CFPS). The optimal parameters with a high yield of 9.32% were as follows: mass fraction of (NH 4 ) 2 SO 4 , 20.0% (w/v); amount of t-butanol, 9.8mL; temperature, 35.3°C; extraction time, 30min; and pH 6.0. The purified CFPS after TPP consisted of d-glucose, d-glucosamine, and d-mannose in a molar ratio of 57.1: 5.6:1.0 with high purity (86.5%) and different molecular weights (1311.1 and 41.5-92.8kDa). Amino acid analysis, UV-vis absorption and Fourier transform-infrared spectra indicated that the purified CFPS was a proteoglycan with O-glycosidic bonds. Moreover, the purified CFPS possessed strong free-radical scavenging abilities and antioxidant activities in vitro. The obtained Trolox equivalent antioxidant capacity and ferric-reducing ability of plasma values were 95.01μmol Trolox/g sample and 38.30μmol Fe 2+ /g sample, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Purification, structural characterization and bioactivity evaluation of a novel proteoglycan produced by Corbicula fluminea.

    Science.gov (United States)

    Yan, Jing-Kun; Wang, Yao-Yao; Qiu, Wen-Yi; Wu, Li-Xia; Ding, Zhi-Chao; Cai, Wu-Dan

    2017-11-15

    A novel proteoglycan, named CFPS-11, was isolated from Corbicula fluminea, which is a food source of freshwater bivalve mollusk. CFPS-11 had an average molecular weight of 807.7kDa and consisted of d-glucose and d-glucosamine in a molar ratio of 12.2:1.0. The protein moiety (∼5%) of CFPS-11 was covalently bonded to the polysaccharide chain in O-linkage type through both serine and thereonine residues. The polysaccharide chain of CFPS-11 was composed of (1→4)-α-d-glucopyranosyl and (1→3,6)-α-d-glucopyranosyl residues, which branched at O-6. The branch chain consisted of (1→)-α-d-glucopyranosyl and (1→)-α-d-N-acetylglucosamine residues. CFPS-11 exhibited significant antioxidant activity in a dose-dependent manner and remarkable inhibition activities against α-amylase and α-glucosidase by in vitro assays. These findings indicated that the CFPS-11 from C. fluminea has the potential for development as a health food ingredient. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Gonadal cycle of Corbicula fluminea (Bivalvia: Corbiculidae) in Pampean streams (Southern Neotropical Region).

    Science.gov (United States)

    Cao, Luciana; Damborenea, Cristina; Penchaszadeh, Pablo E; Darrigran, Gustavo

    2017-01-01

    Corbicula fluminea is an aggressive invasive species of bivalve that arrived into the Río de la Plata River between the late 60's and early 70's, and dispersed widely throughout the Neotropical region, evidencing a great adaptive flexibility to different environmental conditions. This species is a functional hermaphrodite with larval incubation inside the inner demibranch. Despite its widespread distribution, there are no previous studies of complete gonadal histology and reproductive cycle for this species in the Neotropical region. In this study, the reproductive dynamics of C. fluminea in a temperate region, the Santa Catalina Pampean stream, Argentina, is described. Samples of 20-30 individuals were collected monthly from April 2003-April 2005 and processed using traditional histological techniques. During the two years of this study, seven spawning events were recognized. Three major spawns occurred in spring and summer, and other four minor ones during summer and autumn. Events of oocyte recovery were observed after spawning. A high number of incubating individuals was detected. The results stressed the difficulty of identifying a particular pattern of gamete release and of spawning behaviour in this invasive species, especially when inhabiting an unstable environment.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu Shaojun [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China)], E-mail: sjliu@ipp.ac.cn; Huang Qunying [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China); School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230027 (China); Li Chunjing; Huang Bo [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China)

    2009-06-15

    The effect of the size and distribution of non-metal inclusions on mechanical properties of the China low activation martensitic steel (CLAM) was investigated. The tensile and Charpy V-notch impact tests showed that electroslag remelting improved the tensile properties and reduced the ductile brittle transition temperature (DBTT). Inclusion detection of CLAM by optical microscopy and scanning electron microscope showed that both the dimensions and quantities of the alumina inclusions decreased and their distributions became more uniform after remelting. The better refinement and distribution uniformity of alumina inclusions were considered as the main possible reasons for the improvement of the mechanical properties of CLAM steel after remelting.

  8. Fossil clam shells reveal unintended carbon cycling consequences of Colorado River management

    Science.gov (United States)

    Smith, Jansen A.; Auerbach, Daniel A.; Flessa, Karl W.; Flecker, Alexander S.; Dietl, Gregory P.

    2016-09-01

    Water management that alters riverine ecosystem processes has strongly influenced deltas and the people who depend on them, but a full accounting of the trade-offs is still emerging. Using palaeoecological data, we document a surprising biogeochemical consequence of water management in the Colorado River basin. Complete allocation and consumptive use of the river's flow has altered the downstream estuarine ecosystem, including the abundance and composition of the mollusc community, an important component in estuarine carbon cycling. In particular, population declines in the endemic Colorado delta clam, Mulinia coloradoensis, from 50-125 individuals m-2 in the pre-dam era to three individuals m-2 today, have likely resulted in a reduction, on the order of 5900-15 000 t C yr-1 (4.1-10.6 mol C m-2 yr-1), in the net carbon emissions associated with molluscs. Although this reduction is large within the estuarine system, it is small in comparison with annual global carbon emissions. Nonetheless, this finding highlights the need for further research into the effects of dams, diversions and reservoirs on the biogeochemistry of deltas and estuaries worldwide, underscoring a present need for integrated water and carbon planning.

  9. Toxicological responses to acute mercury exposure for three species of Manila clam Ruditapes philippinarum by NMR-based metabolomics.

    Science.gov (United States)

    Liu, Xiaoli; Zhang, Linbao; You, Liping; Cong, Ming; Zhao, Jianmin; Wu, Huifeng; Li, Chenghua; Liu, Dongyan; Yu, Junbao

    2011-03-01

    The Manila clam (Ruditapes philippinarum) has been considered a good sentinel species for metal pollution monitoring in estuarine tidal flats. Along the Bohai coast of China, there are dominantly distributed three species of clams (White, Liangdao Red and Zebra in Yantai population) endowed with distinct tolerances to environmental stressors. In this study, adductor muscle samples were collected from both control and acute mercury exposed White, Liangdao Red and Zebra clams, and the extracts were analyzed by NMR-based metabolomics to compare the metabolic profiles and responses to the acute mercury exposure to determine the most sensitive clam species capable of acting as abioindicator for heavy metal pollution monitoring. The major abundant metabolites in the White clam sample were branched-chain amino acids (leucine, isoleucine and valine), lactate, arginine, aspartate, acetylcholine, homarine and ATP/ADP, while the metabolite profile of Zebra clam sample comprised high levels of glutamine, acetoacetate, betaine, taurine and one unidentified metabolite. For the Liangdao Red clam sample, the metabolite profile relatively exhibited high amount of branched-chain amino acids, arginine, glutamate, succinate, acetylcholine, homarine and two unassigned metabolites. After 48h exposure of 20μgL(-1) Hg(2+), the metabolic profiles showed significant differences between three clam species, which included increased lactate, succinate, taurine, acetylcholine, betaine and homarine and decreased alanine, arginine, glutamine, glutamate, acetoacetate, glycine and ATP/ADP in White clam samples, and elevated succinate, taurine and acetylcholine, and declined glutamine, glycine, and aspartate in Liangdao Red clam samples, while the increased branched-chain amino acids, lactate, succinate, acetylcholine and homarine, and reduced alanine, acetoacetate, glycine and taurine were observed in the Zebra clam samples. Overall, our findings showed that White clams could be a preferable

  10. The impact of bleaching on the metabolic contribution of dinoflagellate symbionts to their giant clam host

    National Research Council Canada - National Science Library

    LEGGAT, W; BUCK, B. H; GRICE, A; YELLOWLEES, D

    2003-01-01

    .... This report is the first to quantify the effects of bleaching on inorganic carbon (C i ) and ammonium flux, fixation and export of photosynthate to the host, in this case the giant clam Tridacna gigas...

  11. 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...

  12. Population Dynamics of the Giant Clam, Tridacna maxima, at Rose Atoll

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — There is a paucity of knowledge on the population dynamics of the giant clams of the family Tridacnidae. Such information on population dynamics is necessary for...

  13. Contaminant assessment of fish, rangia clams, and sediments in the Lower Pamlico River, North Carolina

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Samples of sediment, rangia clams (Rangia cuneata), gizzard shad (Dorosoma cepedianum), and longnose gar (Lepisosteus osseus) were collected from five sites in the...

  14. A theoretical individual-based model of Brown Ring Disease in Manila clams, Venerupis philippinarum

    Science.gov (United States)

    Paillard, Christine; Jean, Fred; Ford, Susan E.; Powell, Eric N.; Klinck, John M.; Hofmann, Eileen E.; Flye-Sainte-Marie, Jonathan

    2014-08-01

    An individual-based mathematical model was developed to investigate the biological and environmental interactions that influence the prevalence and intensity of Brown Ring Disease (BRD), a disease, caused by the bacterial pathogen, Vibrio tapetis, in the Manila clam (Venerupis (= Tapes, = Ruditapes) philippinarum). V. tapetis acts as an external microparasite, adhering at the surface of the mantle edge and its secretion, the periostracal lamina, causing the symptomatic brown deposit. Brown Ring Disease is atypical in that it leaves a shell scar that provides a unique tool for diagnosis of either live or dead clams. The model was formulated using laboratory and field measurements of BRD development in Manila clams, physiological responses of the clam to the pathogen, and the physiology of V. tapetis, as well as theoretical understanding of bacterial disease progression in marine shellfish. The simulation results obtained for an individual Manila clam were expanded to cohorts and populations using a probability distribution that prescribed a range of variability for parameters in a three dimensional framework; assimilation rate, clam hemocyte activity rate (the number of bacteria ingested per hemocyte per day), and clam calcification rate (a measure of the ability to recover by covering over the symptomatic brown ring deposit), which sensitivity studies indicated to be processes important in determining BRD prevalence and intensity. This approach allows concurrent simulation of individuals with a variety of different physiological capabilities (phenotypes) and hence by implication differing genotypic composition. Different combinations of the three variables provide robust estimates for the fate of individuals with particular characteristics in a population that consists of mixtures of all possible combinations. The BRD model was implemented using environmental observations from sites in Brittany, France, where Manila clams routinely exhibit BRD signs. The simulated

  15. 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

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

    Science.gov (United States)

    Lin, Chia-Hao; Yeh, Po-Ling; Lee, Tsung-Han

    2016-01-01

    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 the

  17. 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.

    , which is crucial in aquaculture development. Key words: Gametogenic development, mud clam, Polymesoda erosa, reproduction, spawning Introduction The process of reproduction is the generation of new individuals that have the potential to become mem- bers... based on 10 mm intervals. A total of 185 individuals were used only for fecundity studies, whereas a total of 588 indivi- duals were used for other parameters. After collec- tion, the clams were brought to the laboratory, washed of all mud and towel...

  18. 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.

  19. 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 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.

  20. Relative importance of burrow sediment and porewater to the accumulation of trace metals in the clam Amiantis umbonella.

    Science.gov (United States)

    Tarique, Qaiser; Burger, Joanna; Reinfelder, John R

    2013-07-01

    The objectives of this study were to evaluate the infaunal, facultative deposit-feeding clam Amiantis umbonella as a bioindicator of trace-metal contamination and the relative importance of clam burrow sediment and porewater to total accumulation in an urban/industrial coastal environment. Concentrations of eight trace metals (cadmium [Cd], chromium, copper, mercury [Hg], nickel, lead [Pb], vanadium, and zinc) were measured in the soft tissues of clams and in sediment and porewater from clam burrows along a 5-km transect from desalination/power plant discharges in inner Kuwait Bay. All metals had significantly greater concentrations in clams collected near the desalination/power plant discharges than from the reference site and exhibited decreasing trends with distance from the point source in clam soft tissues and burrow sediment and porewater. Concentrations of Hg (1-9 ppm [dry weight]) and the highest concentrations of Pb (3 ppm) and Cd (7 ppm) in clams from contaminated sites in Kuwait Bay were greater than human consumption limits. Metal concentrations in clams were correlated with those in burrow sediment and porewater across all sites and at sites closest to the point source but not within the reference site. The concentrations of all metals, except Pb, in clams from the contaminated sites were more highly correlated with those in clam burrow sediment than porewater. Concentrations of Pb in clam soft tissues were more strongly correlated with those in burrow porewater than sediment. These results indicate that A. umbonella is an excellent bioindicator of trace metal contamination and that sediment is an important source of contaminant metals to this infaunal clam; however, the source of each metal must be evaluated separately.

  1. The influence of lead on different proteins in gill cells from the freshwater bivalve, Corbicula fluminea, from defense to repair biomarkers.

    Science.gov (United States)

    Rocha, Caroline T; Souza, Marta M

    2012-01-01

    The objective of this study was to evaluate the influence of lead (Pb) on regulatory proteins linked to mechanisms of animal adaptation to polluted environments (using in vivo and in vitro tests) and to validate the in vitro assay as a tool for environmental assessment. Specimens of the bivalve Corbicula fluminea were exposed to nominal concentrations of Pb 5 mg l(-1) for 96 h. Isolated gill cells were exposed to three concentrations (1, 10, and 100 μM) for 5 h. Metal toxicity was evaluated by cell viability (trypan blue exclusion). We also analyzed Na+/K+ adenosine triphosphatase (ATPase) and carbonic anhydrase activity. Additionally, the multixenobiotic-resistance (MXR) phenotype was evaluated by the accumulation of rhodamine B (RB). Immunolabeling was used to quantify the expression of P-glycoproteins (C219) and proteins involved in ion transport, water movement, and cellular repair using antibodies against Na+/K+ ATPase, aquaporin 1, and heat-shock protein 70 (Hsp70). Pb was shown to be toxic in both in vivo and in vitro tests, in which cellular viability significantly decreased by approximately 25%. Cellular viability in the in vivo assays was determined by gill cell isolation after the entire animal was exposed to Pb. We observed that Na+/K+ ATPase activity was inhibited by 70%. Also, the expression of the MXR phenotype significantly increased in our in vivo tests. A statistically significant difference was observed in the expression of all proteins in the in vitro assays, whereas only Hsp70 increased in vivo. Employing these analyses, we could validate the sensitivity of the in vitro tests and can propose our in vitro model as a possible tool for environmental assessment.

  2. Genetic and shell morphological variability of the invasive bivalve Corbicula fluminea (Müller, 1774) in two Portuguese estuaries

    Science.gov (United States)

    Sousa, Ronaldo; Freire, Ruth; Rufino, Marta; Méndez, Josefina; Gaspar, Miguel; Antunes, Carlos; Guilhermino, Lúcia

    2007-08-01

    The identification of different species inside the Corbicula genus is complicated due to the high variation of shell shape, colour and sculpture of the individuals. The species Corbicula fluminea has been present in the River Minho estuary (NW Portugal) at least since 1989. More recently, individuals of the same genus colonized an adjacent estuary (River Lima estuary). Although appearing also to be C. fluminea, the individuals of the Lima estuary differ from those of Minho estuary in the colour and shape of the shell. Therefore, the two populations were compared by conventional morphometric measures (shell length, width and height), geometric morphometric methods (landmarks analysis using the interior of the shell) and genetic analysis (based on the mitochondrial cytochrome c oxidase subunit I gene sequence). Genetic analysis showed an identical mtCOI sequence indicating that both populations belong to the species C. fluminea. However, results of conventional and geometric morphometric analysis showed significant differences in shell shape between individuals from the two populations. These differences may be due to (a) phenotypical plasticity in response to different environmental and/or ecological conditions existing in the two estuaries, (b) different origins of the populations and/or distinct routes until reaching the two estuaries and (c) inter-population genetic differences caused by processes occurring after the introduction of the species in the two estuaries (e.g. differential selection).

  3. Caracterização morfológica e molecular de Corbicula (Mollusca, Bivalvia no reservatório de Rosana, Brasil - DOI: 10.4025/actascibiolsci.v27i4.1274 Morphological and molecular characterization of Corbicula (Mollusca, Bilvalvia at Rosana Resevoir, Brazil - DOI: 10.4025/actascibiolsci.v27i4.1274

    Directory of Open Access Journals (Sweden)

    Alberto José Prioli

    2005-03-01

    Full Text Available O objetivo do presente estudo foi verificar através de técnicas moleculares, RAPD e ISSR aliadas à caracterização morfológica da concha dos bivalves, se os indivíduos morfologicamente distintos de Corbicula fluminea amostrados no reservatório de Rosana pertencem a espécies diferentes. O tecido muscular do pé dos três grupos (G1, G2 e G3 de Corbicula foi removido e congelado em nitrogênio líquido para a análise do DNA. As variáveis morfométricas das conchas indicaram diferenças significativas entre os indivíduos de Corbicula. Por outro lado, as análises moleculares revelaram similaridade genética, evidenciando a não existência de polimorfismo molecular. Os resultados confirmam que os dois grupos diferentes morfologicamente também pertencem a espécie C. fluminea, demonstrando a ocorrência de plasticidade fenotípica, provavelmente causada por fatores bióticos ou ambientaisThe purpose of the present study was to verify, using RAPD and ISSR molecular techniques associated with the morphological characterization of bivalve shells, if the morphologically distinct specimens of Corbicula fluminea sampled at Rosana Reservoir belong to different species. The foot muscle tissue of the three groups (G1, G2, and G3 of Corbicula was removed and frozen in liquid nitrogen to the DNA analyze. Morphometric variables of the shell indicated significant differences among the specimens of Corbicula. On the other hand, molecular analyses revealed genetic similarity among the specimens, showing the nonexistence of molecular polymorphism. The data confirmed that the two morphologically different groups also belong to the species C. fluminea, showing the occurrence of phenotypic plasticity, probably caused by environmental or biotic factors

  4. 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.

  5. Structure of Manila Clam (Ruditapes philippinarum) Microbiota at the Organ Scale in Contrasting Sets of Individuals.

    Science.gov (United States)

    Meisterhans, Guillaume; Raymond, Natalie; Girault, Emilie; Lambert, Christophe; Bourrasseau, Line; de Montaudouin, Xavier; Garabetian, Frédéric; Jude-Lemeilleur, Florence

    2016-01-01

    Marine invertebrate microbiota has a key function in host physiology and health. To date, knowledge about bivalve microbiota is poorly documented except public health concerns. This study used a molecular approach to characterize the microbiota associated with the bivalve Manila clam (Ruditapes philippinarum) by determining (1) the difference among organs either or not under the influence of host habitat, (2) small-scale variability of microbiota, and (3) the experimental response of the Manila clam microbiota submitted to different lateral transmissions. These questions were investigated by sampling two groups of individuals living in contrasting habitats and carrying out a transplant experiment. Manila clam microbiota (i.e., bacterial community structure) was determined at organ-scale (gills, gut, and a pool of remaining tissues) by capillary electrophoresis DNA fingerprinting (CE fingerprinting). The Manila clam microbiota structure differed among organs indicating a selection of Manila clam microbiota at organ scale. Habitat strongly influenced gill and gut microbiota. In contrast, microbiota associated with remaining tissues was similar between group individuals suggesting that these communities are mostly autochthonous, i.e., Manila clam specific. Transplant experiment showed that improving living condition did not induce any change in microbiota associated with remaining tissues. In contrast, the reduction in individual habitat quality led to individuals in declining health as strongly suggested by the increase in phagocytosis activity and decrease in condition index together with the change in internal organ microbiota. This study provides a first description of the Manila clam holobiont which can withstand disturbance and respond opportunistically to improved environmental conditions.

  6. Field Validation of Toxicity Tests to Evaluate the Potential for Beneficial Use of Produced Water

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Bidwell; Jonathan Fisher; Naomi Cooper

    2008-03-31

    This study investigated potential biological effects of produced water contamination derived from occasional surface overflow and possible subsurface intrusion at an oil production site along the shore of Skiatook Lake, Oklahoma. We monitored basic chemistry and acute toxicity to a suite of standard aquatic test species (fathead minnow-Pimephales promelas, Daphnia pulex, Daphnia magna, and Ceriodaphnia dubia) in produced water and in samples taken from shallow groundwater wells on the site. Toxicity identification evaluations and ion toxicity modeling were used to identify toxic constituents in the samples. Lake sediment at the oil production site and at a reference site were also analyzed for brine intrusion chemically and by testing sediment toxicity using the benthic invertebrates, Chironomus dilutus, and Hyallela azteca. Sediment quality was also assessed with in situ survival and growth studies with H. azteca and the Asian clam, Corbicula fluminea, and by benthic macroinvertebrate community sampling. The produced water was acutely toxic to the aquatic test organisms at concentrations ranging from 1% to 10% of the whole produced water sample. Toxicity identification evaluation and ion toxicity modeling indicated major ion salts and hydrocarbons were the primary mixture toxicants. The standardized test species used in the laboratory bioassays exhibited differences in sensitivity to these two general classes of contaminants, which underscores the importance of using multiple species when evaluating produced water toxicity. Toxicity of groundwater was greater in samples from wells near a produced water injection well and an evaporation pond. Principle component analyses (PCA) of chemical data derived from the groundwater wells indicated dilution by lake water and possible biogeochemical reactions as factors that ameliorated groundwater toxicity. Elevated concentrations of major ions were found in pore water from lake sediments, but toxicity from these ions was

  7. Comparative sensitivity of European native (Anodonta anatina) and exotic (Corbicula fluminea) bivalves to mercury

    Science.gov (United States)

    Oliveira, Patrícia; Lopes-Lima, Manuel; Machado, Jorge; Guilhermino, Lúcia

    2015-12-01

    Pollution is believed to be an important factor modulating the competition between exotic invasive bivalves and their native competitors. Thus, the objective of the present study was to compare the sensitivity of the European native Anodonta anatina and the exotic invasive species Corbicula fluminea to mercury, a ubiquitous environmental contaminant of high concern. In laboratory acute bioassays, adult organisms of both species were exposed independently to mercury for 96 h (31-500 μg/L). The criteria indicative of toxicity were mortality and biomarkers of oxidative stress and damage, neurotoxicity, and energy production changes. Mercury induced mortality in A. anatina (72 h-LC10 and 72 h-LC50 of 14.0 μg/L and 49.6 μg/L, respectively) but not in C. fluminea. The ability of C. fluminea to maintaining the shell closed for considerable periods of time when exposed to high concentrations of mercury and the effective activation (up to 63 μg/L) of mechanisms against the oxidative stress caused by mercury may have contributed to its relatively low sensitivity. In the range of concentrations tested, mercury had no significant effects on the other parameters analysed in C. fluminea. Overall, the findings of the present study, suggest that in real scenarios of competition between C. fluminea and A. anatina populations, the presence of mercury may modulate the process, acting in favour of the exotic species because it is less sensitive to this environmental contaminant than the native bivalve. The results of the present study highlight the need of further investigation on the effects of mercury on the competition between exotic invasive species and their native competitors, especially the effects potentially induced by long-term exposure to low concentrations of this metal, the mechanisms involved in the tolerance to mercury-induced stress, and the potential post-exposure recovery of both exotic invasive and native bivalves. This knowledge is most important for

  8. Seasonal variation of metals in seawater, sediment, and Manila clam Ruditapes philippinarum from China.

    Science.gov (United States)

    Zhao, Liqiang; Yang, Feng; Wang, Yuan; Huo, Zhongming; Yan, Xiwu

    2013-06-01

    Concentrations of trace metals (Cu, Pb, Zn, Cd, Cr, Hg, and As) were determined for the first time in seawater, sediment, and Manila clam from Deer Island, Liaoning Province, China. The seawater, sediment, and clam samples were collected seasonally at three clam farming sites around Deer Island during 2010-2011. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg, and As in the seawater samples were 4.16, 0.72, 5.88, 0.45, 2.51, 0.03, and 1.02 μg/l, respectively. The seasonal variations of trace metals in seawater showed a significant difference in the concentrations of Cu, Pb, Zn, Hg, and As among seasons. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg, and As in the sediment samples were 6.43, 13.80, 53.08, 1.10, 36.40, 0.05, and 4.78 mg/kg dry weight, respectively. Trace metal concentrations in sediment seasonally varied significantly except for Cd and Hg. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg, and As in the clam samples were 11.28, 0.61, 92.50, 0.58, 3.98, 0.03, and 1.98 mg/kg dry weight, respectively. Concentrations of Cu, Zn, Cd, Cr, and As in Manila clam showed marked seasonal fluctuations with significant difference. Cu and Zn were the metals with the highest mean biosediment accumulation factor values in Manila clam. Besides, significant correlations for the concentrations of Cu and Zn relative to their concentrations in sediment were also found. Such differences in regression analyzes may be explained by differential bioaccumulation of essential and xenobiotic metals. Concentrations of trace metals in Manila clam did not exceed the maximum established regulatory concentrations for human consumption. Moreover, the calculations revealed that the estimated daily intake values for the examined clam samples were below the internationally accepted dietary guidelines and the calculated hazard quotient values were well less than 1, thus strongly indicating that health risk associated with the intake studied metals through the consumption

  9. Environmental context and trophic trait plasticity in a key species, the tellinid clam Macoma balthica L

    DEFF Research Database (Denmark)

    Törnroos, Anna; Nordström, M. C.; Aarnio, K.

    2015-01-01

    Species show varying levels of plasticity regarding morphology, physiology and behaviour in relation to their immediate environment, and several trait characteristics are habitat-dependent. Determining when and how the environmental context changes trait expression is of key importance for unders......Species show varying levels of plasticity regarding morphology, physiology and behaviour in relation to their immediate environment, and several trait characteristics are habitat-dependent. Determining when and how the environmental context changes trait expression is of key importance...... for understanding the role of individual species for ecosystem functioning. The tellinid clam Macoma balthica can vary its feeding behaviour, shifting between deposit- and suspension-feeding. In order to study the context-dependency of this trophic plasticity in adult clams, we conducted an experiment assessing...... showing differing isotopic signatures from clams at their original habitat, over time mirroring the changes in clams in the site to which they were transferred. The shift in carbon and nitrogen stable isotopes of the clams provides insights into the context-dependent intraspecific feeding plasticity...

  10. Transcriptomic responses to low temperature stress in the Manila clam, Ruditapes philippinarum.

    Science.gov (United States)

    Nie, Hongtao; Jiang, Liwen; Huo, Zhongming; Liu, Lianhui; Yang, Feng; Yan, Xiwu

    2016-08-01

    The Manila clam, Ruditapes philippinarum, is an economically important shellfish in marine aquaculture, with a broad thermal tolerance. The ability to cope with cold stress is quite important for the survival of aquatic species under natural conditions. A cold-tolerant clam that can survive the winter at temperatures below 0 °C might extend our understanding of the mechanisms underlying the response to cold stress. In this study, the transcriptional response of the Manila clam to cold stress (-1 °C) was characterized using RNA sequencing. The transcriptomes of a cold-treatment (O) group of clams, which survived under cold stress, and the control group (OC2), which was not subjected to cold stress, were sequenced with the Illumina HiSeq platform. In all, 148,593 unigenes were generated. Compared with the unigene expression profile of the control group, 1760 unigenes were up regulated and 2147 unigenes were down regulated in the O group. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed that signal transduction, mitochondrial metabolism, cellular component organization or biogenesis, and energy production processes were the most highly enriched pathways among the genes that were differentially expressed under cold stress. All these pathways could be assigned to the following biological functions in the cold-tolerant Manila clam: signal response to cold stress, antioxidant response, cell proliferation, and energy production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Aquaculture Land-Use Policy: The Case of Clam Farming in Thaibinh Province, Vietnam

    Directory of Open Access Journals (Sweden)

    Thi Thu Hang NGO

    2016-12-01

    Full Text Available Policy-making and enforcement remains centralized in Vietnam. Policies have been formulated with less scientific and public justification, thus being largely bureaucratic and infeasible, and in many cases, they have created plagues for people at the grass-roots levels. This article focuses on the implementation of policies related to intertidal land-use and supports for clam farming in the Thaibinh province as a case study to explore the impacts of policies on clam farming and farmers. During the period of 2011–2013, provincial policies on intertidal land allocation and technical and financial supports had boosted clam farming development in the province to a surprising extent. Rapid expansion of the clam farming area has created significant consequences for the farming sector, as well as farmer’s lives. However, for the same provincial policies, but with different enforcement, different farming outcomes for clam farmers in the three study communes have resulted. Where farmers had more of a voice and choice in bidding for the intertidal areas they preferred, they faced fewer problems. It is, thus, suggested that a more decentralized policy-making and enforcement are needed, in which more scientific assessment and farmer participation are required to not only make government policy more successful in supporting farmers and achieving their expected outcomes, but also to provide farmers with more room to make their own farming decisions from which farming and marketing risks could be mitigated.

  12. Differential metabolic responses of clam Ruditapes philippinarum to Vibrio anguillarum and Vibrio splendidus challenges.

    Science.gov (United States)

    Liu, Xiaoli; Ji, Chenglong; Zhao, Jianmin; Wu, Huifeng

    2013-12-01

    Clam Ruditapes philippinarum is one of the important marine aquaculture species in North China. However, pathogens can often cause diseases and lead to massive mortalities and economic losses of clam. In this work, we compared the metabolic responses induced by Vibrio anguillarum and Vibrio splendidus challenges towards hepatopancreas of clam using NMR-based metabolomics. Metabolic responses suggested that both V. anguillarum and V. splendidus induced disturbances in energy metabolism and osmotic regulation, oxidative and immune stresses with different mechanisms, as indicated by correspondingly differential metabolic biomarkers (e.g., amino acids, ATP, glucose, glycogen, taurine, betaine, choline and hypotaurine) and altered mRNA expression levels of related genes including ATP synthase, ATPase, glutathione peroxidase, heat shock protein 90, defensin and lysozyme. However, V. anguillarum caused more severe oxidative and immune stresses in clam hepatopancreas than V. splendidus. Our results indicated that metabolomics could be used to elucidate the biological effects of pathogens to the marine clam R. philippinarum. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Multiple biomarkers of biological effects induced by cadmium in clam Ruditapes philippinarum.

    Science.gov (United States)

    Ji, Chenglong; Wu, Huifeng; Zhou, Mo; Zhao, Jianmin

    2015-06-01

    Cadmium (Cd) is a known heavy metal pollutant in the Bohai Sea. Manila clam Ruditapes philippinarum is an important fishery species along the Bohai coast. In this study, the biological effects induced by two concentrations (20 and 200 μg/L) of Cd were characterized using multiple biochemical indices in the digestive glands of clam R. philippinarum. The total hemocyte counts, reactive oxygen species productions and antioxidant enzyme activities exhibited that Cd induced dose-dependent immune and oxidative stresses in clam digestive glands. Metabolic responses indicated that both Cd exposures caused immune stress marked by the elevated branched chain amino acids (valine, leucine and isoleucine), together with the disturbance in energy metabolism. The differential metabolic biomarkers related to osmotic stress, including homarine, betaine, tyrosine and phenylalanine, suggested the differential responsive mechanisms in clam digestive glands induced by Cd exposures. In addition, both Cd treatments enhanced the anaerobiosis metabolism in clam digestive glands via differential metabolic pathways. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Phylogenetic diversity and functional characterization of the Manila clam microbiota: a culture-based approach.

    Science.gov (United States)

    Leite, Laura; Jude-Lemeilleur, Florence; Raymond, Natalie; Henriques, Isabel; Garabetian, Frédéric; Alves, Artur

    2017-09-01

    According to the hologenome theory, the microbiota contributes to the fitness of the holobiont having an important role in its adaptation, survival, development, health, and evolution. Environmental stress also affects the microbiota and its capability to assist the holobiont in coping with stress factors. Here, we analyzed the diversity of cultivable bacteria associated with Manila clam tissues (mantle, gills, hemolymph) in two non-contaminated sites (Portugal and France) and one metal-contaminated site (Portugal). A total of 240 isolates were obtained. Representative isolates (n = 198) of the overall diversity were identified by 16S rDNA sequencing and subjected to functional characterization. Isolates affiliated with Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. Proteobacteria (mostly Pseudoalteromonadaceae and Vibrionaceae) were dominant in non-contaminated sites while Actinobacteria (mostly Microbacteriaceae) dominated in the metal-contaminated site. The main factor affecting the microbiota composition was contamination. No significant differences were observed between clam tissues and geographic regions. Several isolates tested positive for antibacterial activity, biofilm formation, protease, and siderophore production. The results show that the Manila clam harbors a diverse microbiota that may contribute to clam protection and overall fitness, as well as to its adaptation to stressful environments. In addition, the Manila clam microbiota is revealed as a promising source of novel probiotics with potential application in aquaculture.

  15. Euclidean Genetic Distances of Four Manila Clam (Ruditapes philippinarum) Populations analyzed by PCR Research.

    Science.gov (United States)

    Yoon, Jong-Man

    2017-09-01

    The PCR analysis was performed on DNA samples extracted from a total of 20 individuals using six oligonucleotides primers. The author accomplished clustering analyses to reveal the Euclidean genetic distances among four clam populations from Gochang, Seocheon, Taean and Anmyeon of the Korean peninsula. The oligonucleotides primer OPA-08 generated 5 unique loci to each population, approximately 550 bp and 600 bp, respectively, in the MCS population. Especially, the primer OPA-20 generated 15 unique loci to each population, which were identifying each population, approximately 400 bp, 750 bp and 800 bp, in the MCT population. Individuals from MCG clam population (0.637±0.227) exhibited higher bandsharing values than did individuals from MCG clam population (0.402±0.115) (Pclam individuals, the shortest genetic distance that displayed significant molecular differences was between individuals 14 and 15 from the MCT population (genetic distance = 0.094), while the longest genetic distance among the twenty individuals that displayed significant molecular differences was between individuals MCG no. 01 and MCG no. 02 (genetic distance = 0.687). Comparatively, individuals of MCS clam population were fairly closely related to that of MCT clam population, as shown in the hierarchical dendrogram of Euclidean genetic distances.

  16. Efficacy of domestic cooking inactivation of human hepatitis A virus in experimentally infected manila clams (Ruditapes philippinarum).

    Science.gov (United States)

    Pascoli, F; Pezzuto, A; Buratin, A; Piovesana, A; Fortin, A; Arcangeli, G; Toffan, A

    2016-10-01

    The aim of this work was to evaluate the efficacy of domestic cooking in inactivating Manila clams experimentally infected with human hepatitis A virus (HAV). Electronic temperature probes were positioned to measure the internal temperature of Manila clams during domestic cooking. Two batches were infected with 10(7) and 10(5) TCID50  ml(-1) of HAV. The infected whole-in-shell clams were divided into three replicates and cooked on a conventional stove both singularly and in group and removed from the pan at fixed intervals. Pools of three digestive glands were examined by virus isolation for three blind passages and cell culture supernatant tested with real-time PCR. Results showed that 2-min cooking by a traditional domestic method at a temperature close to 100°C, after the opening up of the valves of all the clams, can completely devitalize the HAV in high viral load-infected clams. This is the first study on inactivation of HAV in experimentally infected Manila clams subjected to domestic cooking. At present, labelling all lagoon products as 'requiring cooking before consumption' is highly recommended, but no specifications are given on how long and at what temperature they should be cooked. Considering the high commercial value of Manila clams, our results can provide both the producers and the consumer with useful indications on how to cook clams to prevent the risk of HAV foodborne illness. © 2016 The Society for Applied Microbiology.

  17. Geographic Variations and Genetic Distance of Three Geographic Cyclina Clam (Cyclina sinensis Gmelin) Populations from the Yellow Sea.

    Science.gov (United States)

    Yoon, Jong-Man

    2012-12-01

    The gDNA isolated from Cyclina sinensis from Gochang (GOCHANG), Incheon (INCHEON) and a Chinese site (CHINESE), were amplified by PCR. Here, the seven oligonucleotide decamer primers (BION-66, BION-68, BION-72, BION-73, BION-74, BION-76, and BION-80) were used to generate the unique shared loci to each population and shared loci by the three cyclina clam populations. As regards multiple comparisons of average bandsharing value results, cyclina clam population from Chinese (0.763) exhibited higher bandsharing values than did clam from Incheon (0.681). In this study, the dendrogram obtained by the seven decamer primers indicates three genetic clusters: cluster 1 (GOCHANG 01~ GOCHANG 07), cluster 2 (INCHEON 08~INCHEON 14), cluster 3 (CHINESE 15~CHINESE 21). The shortest genetic distance that displayed significant molecular differences was between individuals 15 and 17 from the Chinese cyclina clam (0.049), while the longest genetic distance among the twenty-one cyclina clams that displayed significant molecular differences was between individuals GOCHANG no. 03 and INCHEON no. 12 (0.575). Individuals of Incheon cyclina clam population was somewhat closely related to that of Chinese cyclina clam population. In conclusion, our PCR analysis revealed a significant genetic distance among the three cyclina clam populations.

  18. Toxicological evaluation of two pedigrees of clam Ruditapes philippinarum as bioindicators of heavy metal contaminants using metabolomics.

    Science.gov (United States)

    Ji, Chenglong; Cao, Lulu; Li, Fei

    2015-03-01

    Heavy metal pollution has been of great concern in the Bohai marine environment. Manila clam Ruditapes philippinarum has been used as a bioindicator in marine toxicology. In this study, NMR-based metabolomics was used to ascertain whether there were significant biological differences between two dominant pedigrees (White and Zebra) of clam and evaluate the suitability of two pedigrees for marine environmental toxicology, together with antioxidant enzymatic analysis. Our results indicated that there were significant biological differences between White and Zebra clams based on the metabolic profiles and antioxidant enzyme activities. In details, the metabolic profiles showed higher levels of amino acids and succinate in Zebra clam digestive glands and higher levels of ATP in White clam digestive glands, respectively. The superoxide dismutase activities in control White and Zebra clam samples were significantly different. Additionally, White clam was more sensitive to Cd based on the significant accumulation of Cd, antioxidant enzymatic alterations and sensitive metabolic changes. Overall, we concluded that White clam could be a preferable bioindicator for marine environmental toxicology. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. EFFECTS OF RECREATIONAL CLAM HARVESTING ON EELGRASS (ZOSTERA MARINA) AND ASSOCIATED INFAUNAL INVERTEBRATES: IN SITU MANIPULATIVE EXPERIMENTS

    Science.gov (United States)

    The effect of recreational clam harvesting on eelgrass (Zostera marina) was experimentally tested by raking or digging for clams in experimental 1-m2 plots located in a Yaquina Bay (Newport, OR) eelgrass meadow. After three monthly treatments, eelgrass measures of biomass, prima...

  20. Variation in genetic traits of the Baltic clam Macoma balthica from a tidal gradient in the subarctic

    NARCIS (Netherlands)

    Hummel, H.; Gunther, C.P.; Bogaards, R.H.; Fedyakov, V.

    1998-01-01

    In a subarctic tidal gradient, strong heterogeneity in genetic traits of the Baltic clam Macoma balthica was found. The heterogeneity was stronger within the intertidal gradient, over a distance of only about GO mi than along a horizontal gradient over a distance of 1200 km in clams from the west

  1. Growth and nutrient budgets (C-N-P) of the manila clam Venerupsis philippinarum in a commercial pond system

    NARCIS (Netherlands)

    Brinke, ten N.; Jansen, H.M.; Verdegem, M.C.J.

    2012-01-01

    To study potential mechanism(s) causing the reduced growth of the clam Venerupis philippinarum at the end of the production cycle, observed in the culture ponds at Zeeland Aquaculture in 2011, specific studies on eco-physiology and nutrient dynamics of individual clams were performed in the culture

  2. 福井県におけるシジミ(Corbicula)の生息状況の中間報告(2008-2014) : タイワンシジミ(Corbicula fluminea)の侵入の脅威

    OpenAIRE

    川崎,隆徳; 川内,一憲; 田中,幸枝; 小鍛治,優; 木元,久; 藤井,豊

    2016-01-01

    福井県に生息する淡水二枚貝のシジミ属(Corbicula)の生息調査を2008年から2014年にかけて行った。その中間結果として,168標本とその生息地を報告する。全標本中の10個体はマシジミ(Corbicula leana)であると形態学的に鑑定された。また,別の2個体も高い信頼性でもってマシジミと同定されている。一方,北潟湖の2個体のみが確実なヤマトシジミ(Corbicula japonica)と鑑定された。残念ながら,久々子湖の個体は,非常に大きな変異を示すため,確実にヤマトシジミであると鑑定できなかった。他はほとんどタイワンシジミ(Corbicula fluminea)と鑑定された。...

  3. [Temporal and spatial distribution characteristics and indicator effects of Corbicula fluminea in coastal flat of Changjiang estuary].

    Science.gov (United States)

    Li, Lina; Chen, Zhenlou; Xu, Shiyuan; Hou, Jing; Bi, Chunjuan; Shi, Guitao

    2006-05-01

    Corbicula fluminea is a kind of macrobenthos commonly seen in the coastal wetland ecosystem of Changjiang estuary. This paper studied the temporal and spatial distribution characteristics of its population density and biomass, and analyzed the heavy metals concentrations in its body and in suspended particles and sediments. The results showed that the distribution of C. fluminea was discrepant in different seasons, sampling sites, and even, sampling sections of same sampling site. The population density and biomass of C. fluminea were higher in spring and autumn but lower in summer, and higher in mid-tidal flat than in low and high flats of Chongming. Its annual average population density and biomass was the maximal in Xupu. C. fluminea had definite accumulation ability to copper and zinc, but not to lead and chromium. There was a significant negative correlation between the lead concentrations in C. fluminea and sediments.

  4. Occurrence of the invasive species Corbicula fluminea (Bivalvia, Corbiculidae in the Sapucaí River (São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Marina Peixoto Vianna

    2010-01-01

    Full Text Available Biological invasions are gaining increasing importance due to the ecological damage and economic impacts caused by the invaders. Corbicula fluminea (Müller, 1774 is an invasive exotic bivalve introduced into Brazil in the 1970's, and it has colonized the major rivers of the south and southeast. This species, owing to its adaptations to the environment, speed of colonization and reproductive success among others parameters, quickly occupies the substrates preferred by the natives. The present study registers its occurrence in Sapucaí River, São Paulo State. Samples were taken at two different sites of the river with different substrates, one sandy and another muddy. Granulometric analysis and determination of the organic matter content of the sediment were then conducted. The individuals captured in sandy sediment showed higher densities, higher average size, and therefore higher average biomass.

  5. Metallothionein coding sequence identification and seasonal mRNA expression of detoxification genes in the bivalve Corbicula fluminea.

    Science.gov (United States)

    Bigot, Aurélie; Doyen, Périne; Vasseur, Paule; Rodius, François

    2009-02-01

    The aim of this study was to identify a metallothionein (MT) coding sequence from the freshwater bivalve Corbicula fluminea and to measure the seasonal transcriptional pattern of MT in parallel with several detoxification genes: superoxide dismutase (SOD), catalase (CAT), glutathione S-transferases (GST) and glutathione peroxidases (GPx), in the digestive gland and the gills of this bivalve during a 1-year period. We identified a C. fluminea MT complete cDNA sequence using RT-PCR and RACE-PCR. The amino acid sequence deduced from the coding sequence encodes for a protein of 73 amino acids containing 21 cysteine residues. This protein exhibits high identities and similarities with the MT sequences of numerous bivalves. MT, SOD, CAT, pi-GST and Se-GPx expression patterns did not exhibit major seasonal variations. A slight increase of MT was observed in July. Therefore, the mRNA expression of these five genes could be used as biomarkers for monitoring studies.

  6. Detection and analysis of the microdistribution of uranium in the gills of freshwater Corbicula fluminea by SIMS technique

    Science.gov (United States)

    Tessier, C.; Suhard, D.; Simon, O.; Floriani, M.; Rebière, F.; Jourdain, J.-R.

    2009-06-01

    The microdistribution of uranium in the gills of freshwater bivalve Corbicula fluminea following chronic direct exposure to this radioelement has been investigated using the SIMS technique. Different exposure levels and exposure durations have been studied. The SIMS mass spectra and 238U + ion images produced with a SIMS CAMECA 4F-E7 show an U accumulation with the lower aqueous U concentration (20 μg/L) and the influence of the exposure levels on the bioaccumulation capacities. Furthermore, the ionic images display a heterogeneous distribution of uranium within the gill structure whatever the exposure conditions are. This study, in keeping with the ENVIRHOM French research program, was led to the conclusion that ion microscopy is an appropriate analytical method for trace elements and can give elemental cartography in a biological tissue section.

  7. Occurrence of the invasive species Corbicula fluminea (Bivalvia, Corbiculidae in the Sapucaí River (São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Marina Peixoto Vianna

    2010-09-01

    Full Text Available Biological invasions are gaining increasing importance due to the ecological damage and economic impacts caused by the invaders. Corbicula fluminea (Müller, 1774 is an invasive exotic bivalve introduced into Brazil in the 1970’s, and it has colonized the major rivers of the south and southeast. This species, owing to its adaptations to the environment, speed of colonization and reproductive success among others parameters, quickly occupies the substrates preferred by the natives. The present study registers its occurrence in Sapucaí River, São Paulo State. Samples were taken at two different sites of the river with different substrates, one sandy and another muddy. Granulometric analysis and determination of the organic matter content of the sediment were then conducted. The individuals captured in sandy sediment showed higher densities, higher average size, and therefore higher average biomass.

  8. Detection and analysis of the microdistribution of uranium in the gills of freshwater Corbicula fluminea by SIMS technique

    Energy Technology Data Exchange (ETDEWEB)

    Tessier, C. [IRSN, Direction de la RadioProtection de l' Homme, Service de Dosimetrie Interne, Laboratoire de RadioChimie, IRSN, BP 17, F-92262 Fontenay aux Roses Cedex (France)], E-mail: christine.tessier@irsn.fr; Suhard, D. [IRSN, Direction de la RadioProtection de l' Homme, Service de Dosimetrie Interne, Laboratoire de RadioChimie, IRSN, BP 17, F-92262 Fontenay aux Roses Cedex (France); Simon, O.; Floriani, M. [IRSN, Direction de l' Environnement et de l' Intervention, Service d' Etude du Comportement des Radionucleides dans les ecosystemes, Laboratoire de Radioecologie et d' ecotoxicologie, IRSN, BP F6 Cadarache (France); Rebiere, F.; Jourdain, J.-R. [IRSN, Direction de la RadioProtection de l' Homme, Service de Dosimetrie Interne, Laboratoire de RadioChimie, IRSN, BP 17, F-92262 Fontenay aux Roses Cedex (France)

    2009-06-01

    The microdistribution of uranium in the gills of freshwater bivalve Corbicula fluminea following chronic direct exposure to this radioelement has been investigated using the SIMS technique. Different exposure levels and exposure durations have been studied. The SIMS mass spectra and {sup 238}U{sup +} ion images produced with a SIMS CAMECA 4F-E7 show an U accumulation with the lower aqueous U concentration (20 {mu}g/L) and the influence of the exposure levels on the bioaccumulation capacities. Furthermore, the ionic images display a heterogeneous distribution of uranium within the gill structure whatever the exposure conditions are. This study, in keeping with the ENVIRHOM French research program, was led to the conclusion that ion microscopy is an appropriate analytical method for trace elements and can give elemental cartography in a biological tissue section.

  9. Specific bio-markers of pollution: assessment of the exposure to-and effects of- solid wastes (municipal wastes, cinders) on the bivalve mollusc Corbicula fluminea (Muller, 1774); Biomarqueurs specifiques de pollution: evaluation de l'exposition et des effets precoces des dechets solides (ordures menageres, machefers) a l'egard du mollusque bivalve Corbicula fluminea (Muller, 1774)

    Energy Technology Data Exchange (ETDEWEB)

    Rainglet, F.

    1998-11-02

    There is a continual increase of the volume of wastes produced every year. Incineration is actually used for reducing their volume. The residues produced through this process (cinders) can be used for several road works. Rain leaching of these sites, sometimes close to streams, could lead to the solubilization of noxious elements that could affect aquatic fauna. The present study concerned potential effects of cinders produced in the 'District de Nantes', on a bivalve mollusc (Corbicula fluminea), which inhabits in the Loire and Garonne rivers. We focused on heavy metals (Cu, Cd, Pb and Zn) contained in leachates prepared from cinders. C.fluminea were exposed to leachates, under laboratory controlled conditions during 15 days. Bivalves were exposed to mono-metallic solutions of Cu, Cd, Pb and Zn, under laboratory controlled conditions over a period of 15 days. Translocation experiments were conducted, from a control site to a site potentially submitted to influx of water contaminated through waste leaching. Next, the accumulation of heavy metals (Cu, Cd, Pb and Zn) in the tissues as well as bio-markers of toxic effects (PTM, AChE, Catalase, GST and MDA) indicators of physiological response and/or damage, were analyzed. Moreover inter-annual fluctuations of these parameters were monitored, in order to discriminate between natural variations and pollutant-induced variations. All these data would allow an assessment of potential early effects of cinders on bivalves. Moreover the relevance of using this freshwater species, widespread in streams will be discussed. In fact, when creating other waste disposal areas, the use of robust and autochthonous organisms could be very interesting for environmental quality testing. (author)

  10. High cycle fatigue properties of CLAM steel at 723 K and 823 K

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yanyun; Zhai, Xiangwei; Liu, Shaojun, E-mail: shaojun.liu@fds.org.cn; Li, Chunjing; Huang, Qunying

    2015-11-15

    Highlights: • High cycle fatigue properties of CLAM steel were investigated at 723 K and 823 K. • The condition fatigue limit at N = 10{sup 7} were 275 MPa and 235 MPa at 723 K and 823 K. • Fatigue strength decreased when stress and temperature increased at 723 K and 823 K. • Dislocation density decrease and subgrain coarsening during the test process were the possible reasons for fatigue limit decrease. - Abstract: This paper highlights the results of a study on the high cycle fatigue strength and fracture mechanism of China Low Activation Martensitic (CLAM) steel. The high cycle fatigue test results showed that the fatigue strength of CLAM steel decreased with the temperature, and the condition fatigue strengths (N = 10{sup 7}) were 275 MPa and 235 MPa at 723 K and 823 K, respectively. The fractograph results indicated that the fractures were mainly initiated from the surface of the specimen.

  11. Impact assessment of agricultural inputs into a Mediterranean coastal lagoon (Mar Menor, SE Spain) on transplanted clams (Ruditapes decussatus) by biochemical and physiological responses.

    Science.gov (United States)

    Campillo, Juan A; Albentosa, Marina; Valdés, N Juliana; Moreno-González, Rubén; León, Víctor M

    2013-10-15

    The Mar Menor is a coastal lagoon threatened by the development of intensive agriculture in the surrounding areas. Large amounts of pesticides from these areas are discharged into El Albujón, a permanent watercourse flowing into the lagoon. We have used a multi-biomarker approach to assess the biological effects of agricultural pollution on a bivalve species. Biomarkers indicative of neurotoxicity (acetylcholinesterase, AChE), oxidative stress (catalase, CAT; glutathione reductase, GR and lipid peroxidation, LPO), phase II biotransformation of xenobiotics (glutathione S-transferase, GST) and physiological stress (scope for growth, SFG) were measured in clams transplanted to four sites of the lagoon (two reference sites and two sites affected by the dispersion of the effluent of the El Albujón), for exposure periods of 7 and 22 days. The hazards of this effluent were also examined by simultaneously measuring up to 83 contaminants (pesticides, PCBs, PAHs and others) in samples of fresh water from the watercourse mouth and seawater from the deployed sites, as well as the bioaccumulation of organochlorinated compounds and PAHs in the transplanted animals. Biomarker responses showed marked differences between reference and affected sites after 7 and 22 days. However it was only after 22 days that principal component analysis (PCA) of the biomarker responses distinguished between clams deployed in sites affected by the dispersion of the effluent of the watercourse and those from the reference sites. The chemical analysis of water showed high concentrations of pesticides close to El Albujón watercourse mouth, with the greatest input flux corresponding to the organophosphate chlorpyrifos, followed by pendimethalin and naphthalene, and at lower levels acenaphthene, terbuthylazine-desethyl and chlorpyrifos-methyl. In this regard, PCA analysis showed that the biological effects of the mixture of pesticides in caged clams after 22 days were reduced levels of AchE and SFG

  12. An overview of the welding technologies of CLAM steels for fusion application

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xizhang, E-mail: kernel.chen@gmail.com [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Huang Yuming [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Madigan, Bruce [Montana Tech. of University of Montana, Butte, MT 59701 (United States); Zhou Jianzhong [School of Mechanical Engineering, Jiangsu University, ZhenJiang, Jiangsu 221013 (China)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Welding technologies of China Low Activation Martensitic steel is overviewed. Black-Right-Pointing-Pointer Most welding technologies in use are discussed and suggestions are given. Black-Right-Pointing-Pointer Proper welding technologies could ensure weld properties but more detailed work are necessary. - Abstract: China Low Activation Martensitic steel (CLAMs), a kind of RAFM steel with Chinese intellectual property rights, is considered as the primary structural material for the China-designed ITER test blanket module (TBM). As one of the key issues in the fabrication of the fusion reactor, the welding technologies of CLAMs are reviewed. Emphasis is placed on the weldability of CLAMs by different welding methods, and on the properties of as-welded and post-weld heat-treated joints. Recent highlights in research and development for the welding of CLAMs show that proper welding procedure could provide welds with adequate tensile strength but the welds exhibit lower impact toughness compared with the base metal. Post-weld heat treatment (PWHT) and the application of ultrasonic energy during TIG welding could dramatically improve impact toughness. Research also shows that welds in CLAMs have sufficient resistance to swelling under irradiation as well as suitable compatibility with liquid LiPb. The microstructure, mechanical and other physical properties of welds are significantly different from those of the base metal due to the complicated welding thermal cycle. The weld joint is the area most likely to fail one or more of the design requirements within the fusion reactor. Therefore significant additional research is necessary to ensure safe application of welded CLAM steel for fusion reactor construction.

  13. Arsenic biokinetics and bioavailability in deposit-feeding clams and polychaetes.

    Science.gov (United States)

    Zhang, Wei; Wang, Wen-Xiong

    2017-10-31

    In the present study, the arsenic (As) biokinetics and bioavailability in two deposit-feeding invertebrates (clams Gafrarium tumidum and polychaetes Nereis succinea) were quantified. Radiotracer techniques were applied to measure the dissolved uptake rate, dietary assimilation efficiency and efflux of As by the clams and polychaetes. Simultaneously, arsenic species analysis was conducted to examine the As biotransformation following dietary uptake. The radiotracer results showed that the uptake rate constant and efflux rate constant were 0.068L/g/d and 0.07d-1, and 0.173L/g/d and 0.09d-1, in the clams and polychaetes, respectively. Sediments labeled for different times (1.5-60 d) with different inorganic/organic As percentages led to diverse assimilation efficiencies of As (35.1-56.1% in the clams, and 51.6-72.6% in the polychaetes). Modeling calculations showed that sediment was a significant source for As bioaccumulation in the two deposit-feeders. After feeding on the spiked sediments, inorganic As (75.6%) was initially the predominant form, but arsenobetaine (AsB) became the predominant compound (>90%) in the clams and polychaetes during depuration, suggesting biotransformation of inorganic As. Combined with the biokinetics and biotransformation measurements, we showed that AsB was more efficiently assimilated and tended to be accumulated, whereas As(III) was less efficiently assimilated and more rapidly eliminated by the two invertebrates. This study demonstrated that As speciation in the sediments as a significant source for As bioaccumulation caused different bioavailability in deposit-feeding clams and polychaetes. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. 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...

  15. 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.

  16. Temporal dynamics of amino and fatty acid composition in the razor clam Ensis siliqua (Mollusca: Bivalvia)

    Science.gov (United States)

    Baptista, Miguel; Repolho, Tiago; Maulvault, Ana Luísa; Lopes, Vanessa M.; Narciso, Luis; Marques, António; Bandarra, Narcisa; Rosa, Rui

    2014-12-01

    Few studies have been conducted on the temporal dynamics of both amino acid (AA) and fatty acid (FA) profiles in marine bivalves. We investigated the seasonal variation of these compounds in the pod razor clam Ensis siliqua in relation to food availability, salinity, water temperature and reproductive cycle. AA content varied between 46.94 and 54.67 % dry weight (DW), and the AAs found in greater quantity were glutamic acid, glycine and aspartic acid. FA content varied between 34.02 and 87.94 mg g-1 DW and the FAs found in greater quantity were 16:0 and 22:6 n-3. Seasonal trends were observed for AAs and FAs. FAs increased with gametogenesis and decreased with spawning while AA content increased throughout spawning. The effect of increasing temperature and high food availability during the spawning season masked the loss of AAs resulting from gamete release. Still, a comparatively greater increase in the contents of glutamic acid and leucine with spawning indicate their possible involvement in a post-spawning gonad recovery mechanism. A post-spawning decrease in 14:0, 16:0, 16:1 n-7, 18:1 n-7 and 18:1 n-9 is indicative of the importance of these FAs in bivalve eggs. An increase in 18:3 n-3, 18:4 n-3, 20:1 n-9 and 20:2 n-6 during gametogenesis suggests their involvement in oocyte maturation. The FA 22:4 n-6, while increasing with spawning, appears to play a role in post-spawning gonad recovery. Salinity did not have an effect on the AA composition. None of the environmental parameters measured had an effect on FA composition.

  17. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (North Atlantic): Softshell Clam.

    Science.gov (United States)

    1986-06-01

    on (Rathbun). J. rp. Mar.BRiol.Fo-Tc molluscan coelomic fluid. Effect of 65: 67-81. change in environment on the carbon dioxide content of the... coelomic Rourne, J. 1967. Digging efficiency fluid. Anaerobic respiration in Mya" trials with a hydraulic clam rake. arenaria. J. Biol. Chem. 45: 23-3.- Fish

  18. Effect of high hydrostatic pressure on murine norovirus in Manila clams.

    Science.gov (United States)

    Arcangeli, G; Terregino, C; De Benedictis, P; Zecchin, B; Manfrin, A; Rossetti, E; Magnabosco, C; Mancin, M; Brutti, A

    2012-04-01

    Eating raw or insufficiently cooked bivalve molluscs contaminated with human noroviruses (NVs) can result in acute cases of gastroenteritis in humans. Manila clams (Ruditapes philippinarum) are particularly prone to exposure to NVs due to the brackish environment in which they are farmed which is known to be susceptible to human faecal contamination. High hydrostatic pressure processing (HHP) is a food treatment technique that has been shown to inactivate NV. In this study we investigated the ability of HHP to inactivate murine norovirus (MNV-1), a recognised surrogate for NV, in experimentally contaminated manila clams. Pools of contaminated live clams were subjected to hydrostatic pressure ranging from 300 to 500 MPa for different time intervals of between one and 10 min. The trial was repeated three times, at monthly intervals. Virus vitality post-treatment was assessed and the data obtained indicates that the use of high hydrostatic pressures of at least 500 MPa for 1 min was effective in inactivating MNV-1. HHP results to be an effective technique that could be applied to industrial process to obtain safe Manila clams ready to eat. © No claim to Italian Government works. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

  19. 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

  20. Genetic diversity of European populations of the invasive soft-shell clam Mya arenaria (Bivalvia)

    NARCIS (Netherlands)

    Lasota, R.; Hummel, H.; Wolowicz, M.

    2004-01-01

    The genetic diversity of the soft-shell clam Mya arenaria from seven locations in Europe (two stations in the southern Baltic Sea (the Gulf of Gdansk) and two in the North Sea (Veerse Meer and Oosterschelde), and three additional stations in the Denmark Straits and Bay of Biscay) was determined

  1. The Quiet Clam Is Quite Calm: Transposed-Letter Neighborhood Effects on Eye Movements during Reading

    Science.gov (United States)

    Johnson, Rebecca L.

    2009-01-01

    In responses time tasks, inhibitory neighborhood effects have been found for word pairs that differ in a transposition of two adjacent letters (e.g., "clam/calm"). Here, the author describes two eye-tracking experiments conducted to explore transposed-letter (TL) neighborhood effects within the context of normal silent reading. In…

  2. 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.

  3. 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...

  4. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (South Atlantic) Hard Clam,

    Science.gov (United States)

    1987-08-01

    North America, based on histological evidence of gametogenic activity and gamete release. The solid lines show periods of peak spawning. Temp. Months...1973; w, ,x-Wells 195Ra,b; y-Whetstone and Fvprso1l O’ crabs, usually feed on the smaller Starfish appear to be important preda- hard clams (Whetstone

  5. Multidrug-resistant and epidemic clones of Escherichia coli from natural beds of Venus clam.

    Science.gov (United States)

    Vignaroli, C; Di Sante, L; Leoni, F; Chierichetti, S; Ottaviani, D; Citterio, B; Biavasco, F

    2016-10-01

    Epidemic Escherichia coli clones have been recovered in marine sediment along the coast of Marche, an Adriatic region in central Italy. In the present study, E. coli strains from the clam Chamelea gallina, sampled from seven natural beds in the same area, were detected. Selected E. coli isolates from all sampling sites were screened for antimicrobial susceptibility, genetic diversity and correlation. The majority (60%) belonged to phylogroups A or B1, 31% to the other groups (B2, C, D, E, F), 8% to cryptic clades, and 1% were untypable. Moreover, 33.3% of isolates were resistant to at least one drug and 11% were multidrug resistant (MDR). The most common resistance was to tetracycline, ampicillin, and streptomycin. No clonality was detected, but the strains' high genetic heterogeneity pointed at multiple sources of microbiological contamination. MLST analysis found potentially pathogenic and even epidemic MDR strains in clams collected in class A (ST746 and ST46) and class B (ST393, ST58 and ST131) areas, indicating that strains of clinical origin are detectable in clams. These data highlight that eating raw or lightly cooked clams may pose a health risk if purification is not performed or is ineffective. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Seasonal variation of biochemical components in clam ( Saxidomus purpuratus Sowerby 1852) in relation to its reproductive cycle and the environmental condition of Sanggou Bay, China

    Science.gov (United States)

    Bi, Jinhong; Li, Qi; Zhang, Xinjun; Zhang, Zhixin; Tian, Jinling; Xu, Yushan; Liu, Wenguang

    2016-04-01

    Seasonal variation of biochemical components in clam ( Saxidomus purpuratus Sowerby 1852) was investigated from March 2012 to February 2013 in relation to environmental condition of Sanggou Bay and the reproductive cycle of clam. According to the histological analysis, the reproductive cycle of S. purpuratus includes two distinctive phases: a total spent and inactive stage from November to January, and a gametogenesis stage, including ripeness and spawning, during the rest of the year. Gametes were generated at a low temperature (2.1°C) in February. Spawning took place once a year from June to October. The massive spawning occurred in August when the highest water temperature and chlorophyll a level could be observed. The key biochemical components (glycogen, protein and lipid) in five tissues (gonad, foot, mantle, siphon and adductor muscle) were analyzed. The glycogen content was high before gametogenesis, and decreased significantly during the gonad development in the gonad, mantle and foot of both females and males, suggesting that glycogen was an important energy source for gonad development. The protein and lipid contents increased in the ovary during the gonad development, demonstrating that they are the major organic components of oocytes. The lipid and protein contents decreased in the testis, implying that they can provide energy and material for spermatogenesis. The results also showed that protein stored in the mantle and foot could support the reproduction after the glycogen was depleted.

  7. The influence of pH and salinity on the toxicity of heavy metals in sediment to the estuarine clam Ruditapes philippinarum.

    Science.gov (United States)

    Riba, Inmaculada; DelValls, T Angel; Forja, Jesús M; Gómez-Parra, Abelardo

    2004-05-01

    An approach is presented for determining the influence of two key variables, pH and salinity (S), on the toxicity of four common heavy metals bound to sediments in estuaries. Two samples of environmental sediment taken from two estuaries in southern Spain (the Huelva estuary and the Guadalquivir River estuary), together with a dilution of toxic mud from the Aznalcóllar (Spain) mining spill (April 1998) were used to determine their toxicity at different values of pH (6.5, 7.5, and 8.5) and salinity (10, 20, and 30) on the estuarine clam Ruditapes philippinarum. Two different endpoints, sublethal, indicated by clam reburial (median effective burial time [ET50]), and relative mortality (median lethal concentration [LC50]), were used to quantify the toxicity associated with the heavy metals. Neither salinity nor pH was found to influence the toxic responses measured by the behavioral endpoint (ET50). However, a strong effect on the LC50 related to pH and salinity was detected, with the toxicity of the heavy metals being increased at low values of both variables (pH = 6.5 and S = 10). The mechanism of heavy metals uptake through water may explain this influence of pH and salinity on the lethal toxicity detected. The results show differences in the toxicity of these heavy metals bound to sediments depending on whether the origin of metal contamination is chronic or acute.

  8. 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.

  9. 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.

  10. Transcriptome sequencing and microarray development for the Manila clam, Ruditapes philippinarum: genomic tools for environmental monitoring.

    Science.gov (United States)

    Milan, Massimo; Coppe, Alessandro; Reinhardt, Richard; Cancela, Leonor M; Leite, Ricardo B; Saavedra, Carlos; Ciofi, Claudio; Chelazzi, Guido; Patarnello, Tomaso; Bortoluzzi, Stefania; Bargelloni, Luca

    2011-05-12

    The Manila clam, Ruditapes philippinarum, is one of the major aquaculture species in the world and a potential sentinel organism for monitoring the status of marine ecosystems. However, genomic resources for R. philippinarum are still extremely limited. Global analysis of gene expression profiles is increasingly used to evaluate the biological effects of various environmental stressors on aquatic animals under either artificial conditions or in the wild. Here, we report on the development of a transcriptomic platform for global gene expression profiling in the Manila clam. A normalized cDNA library representing a mixture of adult tissues was sequenced using a ultra high-throughput sequencing technology (Roche 454). A database consisting of 32,606 unique transcripts was constructed, 9,747 (30%) of which could be annotated by similarity. An oligo-DNA microarray platform was designed and applied to profile gene expression of digestive gland and gills. Functional annotation of differentially expressed genes between different tissues was performed by enrichment analysis. Expression of Natural Antisense Transcripts (NAT) analysis was also performed and bi-directional transcription appears a common phenomenon in the R. philippinarum transcriptome. A preliminary study on clam samples collected in a highly polluted area of the Venice Lagoon demonstrated the applicability of genomic tools to environmental monitoring. The transcriptomic platform developed for the Manila clam confirmed the high level of reproducibility of current microarray technology. Next-generation sequencing provided a good representation of the clam transcriptome. Despite the known limitations in transcript annotation and sequence coverage for non model species, sufficient information was obtained to identify a large set of genes potentially involved in cellular response to environmental stress.

  11. Exploring the effects of seasonality and chemical pollution on the hepatopancreas transcriptome of the Manila clam.

    Science.gov (United States)

    Milan, Massimo; Ferraresso, Serena; Ciofi, Claudio; Chelazzi, Guido; Carrer, Claudio; Ferrari, Giorgio; Pavan, Lino; Patarnello, Tomaso; Bargelloni, Luca

    2013-04-01

    The assessment of marine environmental health is a complex but fundamental task both for ecosystem conservation and food safety related to the human consumption of marine products. Manila clams inhabiting the Venice Lagoon constitute an excellent case study for evaluating the effects of complex mixtures of industrial and urban effluents on aquatic organisms. Clams were collected in different seasons at four locations within the Venice Lagoon. The sampling sites were characterized by a range of pollutant concentrations and included Porto Marghera, a highly polluted industrial area where clam harvesting for human consumption is strictly forbidden. Pooled soft tissues were subjected to mass spectroscopy analysis to measure the concentrations of PCDDs/PCDFs/PCBs-DL, PCBs, PBDEs, HCB and PAHs, and pooled digestive gland samples were used for gene expression profiling. While seasonal variation was found to be responsible for the largest proportion of transcriptional changes, significance analysis of microarrays quantitative correlation analysis identified 162 transcripts that were correlated with at least one class of chemicals measured in the samples from the four different sampling sites. Prediction Analysis of Microarrays (PAM) identified a minimal set of seven genes that correctly assigned samples collected in the restricted polluted area (Porto Marghera), independent of the season in which they were collected. An integrated approach combining transcriptomics and chemical analyses of the Manila clam provided a global picture of how Manila clams respond to complex mixtures of xenobiotics and their interplay with other biotic and abiotic factors. We were also able to identify gene expression signatures for different classes of chemicals and a set of robust biomarkers of exposure to these chemicals. © 2013 Blackwell Publishing Ltd.

  12. Transcriptome sequencing and microarray development for the Manila clam, Ruditapes philippinarum: genomic tools for environmental monitoring

    Science.gov (United States)

    2011-01-01

    Background The Manila clam, Ruditapes philippinarum, is one of the major aquaculture species in the world and a potential sentinel organism for monitoring the status of marine ecosystems. However, genomic resources for R. philippinarum are still extremely limited. Global analysis of gene expression profiles is increasingly used to evaluate the biological effects of various environmental stressors on aquatic animals under either artificial conditions or in the wild. Here, we report on the development of a transcriptomic platform for global gene expression profiling in the Manila clam. Results A normalized cDNA library representing a mixture of adult tissues was sequenced using a ultra high-throughput sequencing technology (Roche 454). A database consisting of 32,606 unique transcripts was constructed, 9,747 (30%) of which could be annotated by similarity. An oligo-DNA microarray platform was designed and applied to profile gene expression of digestive gland and gills. Functional annotation of differentially expressed genes between different tissues was performed by enrichment analysis. Expression of Natural Antisense Transcripts (NAT) analysis was also performed and bi-directional transcription appears a common phenomenon in the R. philippinarum transcriptome. A preliminary study on clam samples collected in a highly polluted area of the Venice Lagoon demonstrated the applicability of genomic tools to environmental monitoring. Conclusions The transcriptomic platform developed for the Manila clam confirmed the high level of reproducibility of current microarray technology. Next-generation sequencing provided a good representation of the clam transcriptome. Despite the known limitations in transcript annotation and sequence coverage for non model species, sufficient information was obtained to identify a large set of genes potentially involved in cellular response to environmental stress. PMID:21569398

  13. Transcriptome sequencing and microarray development for the Manila clam, Ruditapes philippinarum: genomic tools for environmental monitoring

    Directory of Open Access Journals (Sweden)

    Patarnello Tomaso

    2011-05-01

    Full Text Available Abstract Background The Manila clam, Ruditapes philippinarum, is one of the major aquaculture species in the world and a potential sentinel organism for monitoring the status of marine ecosystems. However, genomic resources for R. philippinarum are still extremely limited. Global analysis of gene expression profiles is increasingly used to evaluate the biological effects of various environmental stressors on aquatic animals under either artificial conditions or in the wild. Here, we report on the development of a transcriptomic platform for global gene expression profiling in the Manila clam. Results A normalized cDNA library representing a mixture of adult tissues was sequenced using a ultra high-throughput sequencing technology (Roche 454. A database consisting of 32,606 unique transcripts was constructed, 9,747 (30% of which could be annotated by similarity. An oligo-DNA microarray platform was designed and applied to profile gene expression of digestive gland and gills. Functional annotation of differentially expressed genes between different tissues was performed by enrichment analysis. Expression of Natural Antisense Transcripts (NAT analysis was also performed and bi-directional transcription appears a common phenomenon in the R. philippinarum transcriptome. A preliminary study on clam samples collected in a highly polluted area of the Venice Lagoon demonstrated the applicability of genomic tools to environmental monitoring. Conclusions The transcriptomic platform developed for the Manila clam confirmed the high level of reproducibility of current microarray technology. Next-generation sequencing provided a good representation of the clam transcriptome. Despite the known limitations in transcript annotation and sequence coverage for non model species, sufficient information was obtained to identify a large set of genes potentially involved in cellular response to environmental stress.

  14. Physiological effects of polycyclic aromatic hydrocarbons on soft-shell clam Mya arenaria

    Energy Technology Data Exchange (ETDEWEB)

    Frouin, H. [Institut des Sciences de la Mer de Rimouski, Universite du Quebec a Rimouski, 310 Allee des Ursulines, C.P. 3300, Rimouski, Que. G5L 3A1 (Canada); Pellerin, J. [Institut des Sciences de la Mer de Rimouski, Universite du Quebec a Rimouski, 310 Allee des Ursulines, C.P. 3300, Rimouski, Que. G5L 3A1 (Canada)]. E-mail: jocelyne_pellerin@uqar.qc.ca; Fournier, M. [INRS-Institut Armand Frappier, 245 Hymus Boul., Pointe-Claire, Que. H9R 1G6 (Canada); Pelletier, E. [Institut des Sciences de la Mer de Rimouski, Universite du Quebec a Rimouski, 310 Allee des Ursulines, C.P. 3300, Rimouski, Que. G5L 3A1 (Canada); Richard, P. [Institut des Sciences de la Mer de Rimouski, Universite du Quebec a Rimouski, 310 Allee des Ursulines, C.P. 3300, Rimouski, Que. G5L 3A1 (Canada); Pichaud, N. [Institut des Sciences de la Mer de Rimouski, Universite du Quebec a Rimouski, 310 Allee des Ursulines, C.P. 3300, Rimouski, Que. G5L 3A1 (Canada); Rouleau, C. [Peches et Oceans Canada, Institut Maurice Lamontagne, C.P. 1000, Mont-Joli, Que. G5H 3Z4 (Canada); Garnerot, F. [Institut des Sciences de la Mer de Rimouski, Universite du Quebec a Rimouski, 310 Allee des Ursulines, C.P. 3300, Rimouski, Que. G5L 3A1 (Canada)

    2007-05-01

    The aim of this study was to investigate the effects of polycyclic aromatic hydrocarbons (PAHs) on the physiological status of the bivalve Mya arenaria. Specimens were exposed to four different sources of PAHs: aluminium smelter soot, sediment from an industrial discharge pound, charcoal fine particles and dietary PAHs assessed by feeding clams with phytoplankton freshly impregnated with dissolved PAHs. The exposure period lasted 30 days and bivalves were let to recover for an additional 20 days. At days 8, 15, 30 and 50, immune parameters (phagocytic activity and efficiency) were monitored in haemocytes. Oxidative stress measures such as catalase and lipid peroxidation were quantified in digestive gland as well as concentrations of bioaccumulated PAHs. In a second experiment, clams were exposed to [{sup 14}C]-pyrene via the phytoplankton, and the tissue distribution of radiolabelled compound was studied. Glycogen levels in gonad and digestive gland were also measured and gametogenesis stages were investigated. Results showed a high bioaccumulation in clams exposed to dietary PAHs and contaminated sediments. Tissue distribution of [{sup 14}C]-pyrene revealed that the radiolabelled compound persisted mainly in the gonad during 14 days. A decrease of phagocytosis was observed in contaminated male clams. The lipid peroxidation (malondialdehyde) was found to increase in the digestive gland tissues of clams exposed to dietary PAHs, smelter soot and discharge, but no differences were observed in the catalase activity. A delay in gametogenesis occurred in all exposed males and in females contaminated with coke dust and dietary PAHs. Males were more sensitive than females to PAH exposure. A dysfunction in steroid synthesis is suspected to occur due to the exposure to all sources of PAHs.

  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. Zebra Mussel Chemical Control Guide, Version 2.0

    Science.gov (United States)

    2015-07-01

    mussel (Dreissena polymorpha) and the Asian clam ( Corbicula fluminea ). In: Zebra mussels: Biology, impacts, and control, ed. T. F. Nalepa and D. W...C. Hagen. 1977. Responses of Corbicula to potassium. Proc. First Intl. Corbicula Symp. Texas Christian University, pp 215-225. Fisher, S. A., S. W

  17. Innovative In-Situ Remediation of Contaminated Sediments for Simultaneous Control of Contamination and Erosion. Part 1

    Science.gov (United States)

    2011-08-01

    252 Figure 124. Survival of Corbicula fluminea Held in Cages within Experimental Active Caps in Steel Creek (A = apatite, OC = organoclay, S = sand...plots using three types of benthic organisms including Hyalella azteca, Lumbriculus variegates, and Corbicula fluminea . The organisms were placed...California blackworm), Corbicula fluminea (Asiatic clam), and Hyalella azteca (amphipod). The erosion evaluation was based on visual observations

  18. Field screening of water quality, bottom sediment, and biota associated with irrigation drainage in the Yuma Valley, Arizona, 1995

    Science.gov (United States)

    Tadayon, Saeid; King, K.A.; Andrews, Brenda; Roberts, William

    1997-01-01

    , and concentrations ranged from 11 to 16 micrograms per gram. Concentrations ofaluminum, beryllium, boron, copper, lead, and zinc were highest in samples from Main Drain at southerly international boundary near San Luis, Arizona. Selenium was detected in all bottom-sediment samples, and concentrations ranged from 0.1 to 0.7 micrograms per gram. Concentrations of cadmium, europium, homium, mercury, molybdenum, silver, tantalum, tin, and uranium were below analytical reporting limits in the bottom-sediment samples. Concentrations of trace elements in bottom-sediment samples were within the ranges found in a study of soils of the western United States and did not indicate a significant accumulation of these constituents. p,p'Dichlorodiphenyldichloroethylene (commonly referred to as p,-p'-DDE) was detected in one bottom-sediment sample at a concentration of 1.4 micrograms per gram. No other organochlorine compounds were detected in the bottom-sediment samples. DDE was present in all fish and bird samples. Almost one-half of the fish samples contained DDE residues that were two times higher than the mean calculated for a national study in 1984-85. Twenty-tree percent of the fish contained more than three times the national mean. Fish from downstream parts of the Main Drain had the highest concentrations of DDE. Although concentrations of DDE in fish and in bird carcasses and eggs were above background levels, residues generally were below thresholds associated with chronic poisoning and reproductive problems in figh and wildlife. Concentrations of 18 trace elements were detected in cattail (Typha sp.) roots, freshwater clam (Corbicula fluminea), fish, and bird samples. Selenium in most fish and in livers of red-winged (Agelaius phoeniceus) and yellow-headed (Xanthocephalus xanthocephalus) blackbirds was above background concentrations but below toxic concentrations. In contrast, selenium was present in a killdeer (Charadrium vociferus) liver sample at potentially toxic con

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

    National Research Council Canada - National Science Library

    Van Wynsberge, Simon; Andréfouët, Serge; Gilbert, Antoine; Stein, Arsène; Remoissenet, Georges

    2013-01-01

    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...

  20. Physiological responses of Manila clams Venerupis (=Ruditapes) philippinarum with varying parasite Perkinsus olseni burden to toxic algal Alexandrium ostenfeldii exposure.

    Science.gov (United States)

    Lassudrie, Malwenn; Soudant, Philippe; Richard, Gaëlle; Henry, Nicolas; Medhioub, Walid; da Silva, Patricia Mirella; Donval, Anne; Bunel, Mélanie; Le Goïc, Nelly; Lambert, Christophe; de Montaudouin, Xavier; Fabioux, Caroline; Hégaret, Hélène

    2014-09-01

    Manila clam stock from Arcachon Bay, France, is declining, as is commercial harvest. To understand the role of environmental biotic interactions in this decrease, effects of a toxic dinoflagellate, Alexandrium ostenfeldii, which blooms regularly in Arcachon bay, and the interaction with perkinsosis on clam physiology were investigated. Manila clams from Arcachon Bay, with variable natural levels of perkinsosis, were exposed for seven days to a mix of the nutritious microalga T-Iso and the toxic dinoflagellate A. ostenfeldii, a producer of spirolides, followed by seven days of depuration fed only T-Iso. Following sacrifice and quantification of protozoan parasite Perkinsus olseni burden, clams were divided into two groups according to intensity of the infection ("Light-Moderate" and "Moderate-Heavy"). Hemocyte and plasma responses, digestive enzyme activities, antioxidant enzyme activities in gills, and histopathological responses were analyzed. Reactive oxygen species (ROS) production in hemocytes and catalase (CAT) activity in gills increased with P. olseni intensity of infection in control clams fed T-Iso, but did not vary among A. ostenfeldii-exposed clams. Exposure to A. ostenfeldii caused tissue alterations associated with an inflammatory response and modifications in hemocyte morphology. In the gills, superoxide dismutase (SOD) activity decreased, and an increase in brown cell occurrence was seen, suggesting oxidative stress. Observations of hemocytes and brown cells in tissues during exposure and depuration suggest involvement of both cell types in detoxication processes. Results suggest that exposure to A. ostenfeldii disrupted the pro-/anti-oxidant response of clams to heavy P. olseni intensity. In addition, depressed mitochondrial membrane potential (MMP) in hemocytes of clams exposed to A. ostenfeldii suggests that mitochondrial functions are regulated to maintain homeostasis of digestive enzyme activity and condition index. Copyright © 2014 Elsevier B

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

    Science.gov (United States)

    1983-10-01

    Franz (1977) found 1972). Food particles trapped on the that most surf clams selected by snails mucus -cm4ted inner siphonal surfaces off Long Island...and Murawski and Serchuk Ropes (1982) summarized monthiy (1979, 1981, 1982). The reader is landings and trends of the surf clam ) referred to these...dynamics. For Over this 9-year period, landings at the scope and purpose of this profile, New York, Maryland, ard dslaware only major aspects and trends

  2. Pathologic survey on the Manila clam Ruditapes philippinarum (Adams and Reeve 1850) from Haeju off the western coastal Yellow Sea

    Science.gov (United States)

    Yang, Hyun-Sung; Park, Kwang-Jae; Choi, Kwang-Sik

    2010-06-01

    Pathologic condition of Manila clam, Ruditapes philippinarum collected from Haeju off the west coast of North Korea in February and March 2007 was investigated in this study. The diagnostics included a protozoan parasite, Perkinsus olseni, the brown ring disease (BRD) caused by bacteria Vibrio tapetis and metazoan parasites Trematod and Cestod. P. olseni infection was examined using histology and Ray’s fluid thioglycollate medium (RFTM) assay along with Choi’s NaOH digestion technique. Trematode and cestode infection was also examined from the histology. A total of 140 clams with 35-45 mm in shell length (2-3 years old) were analyzed. Condition factor (CF), a ratio of the wet tissue weight to the shell dry weight, ranged from 0.445±0.074 (February) to 0.544±0.132 (March). Total body burden of P. olseni (i.e. infection intensity) ranged from 18,644±37,755 (February) to 26,933±80,611 cells/g wet tissue (March) with the prevalence of 76.7-43.3% (March) respectively. Prevalence of trematode and cestode infection in February and March varied 22.5-25.0 and 15.0-22.5% respectively. Infection intensity of V. tapetis ranged 1-2 and the prevalence was 1.4 (February) and 5.7% (March). Prevalence and infection intensity of P. olseni in clams from Haeju was comparatively lower than those of clams reported on the west coast of Korea. BRD and the other metazoan parasite infection were also relatively lower or similar to the condition of the clams reported previously. CF of Haeju clams was also relatively higher than the clams in Gyeonggi Bay and Taean, suggesting that Haeju clams had relatively better pathologic and health condition.

  3. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest). Common Littleneck Clam.

    Science.gov (United States)

    1986-04-01

    littleneck clams normally (Quayle and Bourne 1972). Two species live in a relatively narrow range of of tetraphyllidian cestodes were found temperature and...the littleneck clam (Venerupsis staminea with the Schmidt. R.R., and J.E. iWarme. 1969. larval cestode (Echeneibothrium Population characteristics of...Protothaca staminea by two species JI 445-467 in T.J. Conomus, ed. San of Tetraphylldian cestodes Francisco Bay, the unurbanized (Echeneibothrium spp

  4. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest). Common Littleneck Clam.

    Science.gov (United States)

    1987-08-01

    predators switched to the more % clams (Quayle and Bourne 1972). Two abundant deposit-feeding bivalve species of tetraphyllidian cestodes Macoma nasuta...gills and clam (Venerupsis staminea) with a occurrence of copper-binding pro- larval cestode (Echeneibothrium teins. Biol. Bull. (Woods Hole) spp.) J...Protothaca staminea by two species t tetraphylidian cestodes , (Echeneibothrium spp.) J. Inver- Smith, G.M. 1928. Food material as a tebr. Pathol

  5. Accumulation and risk assessment of heavy metals in sediments and zoobenthos (Bellamya aeruginosa and Corbicula fluminea) from Lake Taihu.

    Science.gov (United States)

    Kong, Ming; Hang, Xiaoshuai; Wang, Longmian; Yin, Hongbin; Zhang, Yimin

    2016-01-01

    Accumulation and risk assessment of metals in sediments and zoobenthos (Bellamya aeruginosa and Corbicula fluminea) from Lake Taihu were studied. Results showed that metal (Cr, Cd, Cu, Zn, Pb and Ni) concentrations in Lake Taihu varied greatly, and Cd in the Zhushan Bay showed higher bioavailability compared to the other metals studied. The spatial distribution of metals in B. aeruginosa and C. fluminea was similar to that in sediments. Zn and Cu exhibited the higher mean concentration in B. aeruginosa and C. fluminea, which was in good accordance with its higher content in surrounding sediment. Labile fractions (i.e., acid-soluble (F1), reducible (F2) and F1+F2) of Cu and Zn in sediments showed a significant positive correlation with them in B. aeruginosa (Pfluminea and in sediments. The results of ecological risk assessment showed that Zhushan Bay was seriously contaminated by metal Cd, as it made the main contribution of all the metals. Total target hazard quotients indicated that adults and children both had potential health risk through consuming C. fluminea. Hazard index values suggested that adults and children might experience adverse health effects through consuming B. aeruginosa and C. fluminea.

  6. Cholinesterase characterization in Corbicula fluminea and effects of relevant environmental contaminants: a pesticide (chlorfenvinphos) and a detergent (SDS).

    Science.gov (United States)

    Ramos, Ana S; Gonçalves, Fernando; Antunes, Sara C; Nunes, Bruno

    2012-01-01

    This study characterizes the cholinesterasic forms present in the bivalve Corbicula fluminea, through the analysis of differential affinity towards various substrates and inhibitors. This approach also permitted the validation of cholinesterase inhibition in the mentioned species for monitoring purposes by evaluating the inhibitory activity of a detergent (SDS) and a pesticide (chlorfenvinphos), both in vitro and in vivo. The cholinesterasic form present in the tissues of C. fluminea showed intermediate properties in terms of its relation with substrates and inhibitors. Furthermore, it was not inhibited by the detergent SDS under any of the test conditions, but was clearly inhibited by the selected organophosphate. The data show clearly that the main cholinesterasic form in C. fluminea is responsive to the organophosphate chlorfenvinphos, thus supporting the use of this biomarker for the environmental monitoring of specific contaminants such as anticholinesterasic pesticides. Despite not being commonly attained in the wild, the levels of chlorfenvinphos required to elicit a significant ChE inhibition were only one order of magnitude above actual values of aquatic contamination by this pesticide. Copyright © Taylor & Francis Group, LLC

  7. Dynamic behaviour of Cd2+ adsorption in equilibrium batch studies by CaCO3(-)-rich Corbicula fluminea shell.

    Science.gov (United States)

    Ismail, Farhah Amalya; Aris, Ahmad Zaharin; Latif, Puziah Abdul

    2014-01-01

    This work presents the structural and adsorption properties of the CaCO3(-)-rich Corbicula fluminea shell as a natural and economic adsorbent to remove Cd ions from aqueous solutions under batch studies. Experiments were conducted with different contact times, various initial concentrations, initial solution pH and serial biosorbent dosage to examine the dynamic characterization of the adsorption and its influence on Cd uptake capacity. The characterization of the C. fluminea shell using SEM/EDX revealed that the adsorbent surface is mostly impregnated by small particles of potentially calcium salts. The dominant Cd adsorption mechanism is strongly pH and concentration dependent. A maximum Cd removal efficiency of 96.20% was obtained at pH 7 while the optimum adsorbent dosage was observed as 5 g/L. The Langmuir isotherm was discovered to be more suitable to represent the experimental equilibrium isotherm results with higher correlation coefficients (R(2) > 0.98) than Freundlich (R(2) < 0.97).The correlation coefficient values (p < 0.01) indicated the superiority of the Langmuir isotherm over the Freundlich isotherm.

  8. Proteomic Profiling of Cytosolic Glutathione Transferases from Three Bivalve Species: Corbicula fluminea, Mytilus galloprovincialis and Anodonta cygnea

    Directory of Open Access Journals (Sweden)

    José Carlos Martins

    2014-01-01

    Full Text Available Suspension-feeding bivalves are considered efficient toxin vectors with a relative insensitivity to toxicants compared to other aquatic organisms. This fact highlights the potential role of detoxification enzymes, such as glutathione transferases (GSTs, in this bivalve resistance. Nevertheless, the GST system has not been extensively described in these organisms. In the present study, cytosolic GSTs isoforms (cGST were surveyed in three bivalves with different habitats and life strategies: Corbicula fluminea, Anodonta cygnea and Mytilus galloprovincialis. GSTs were purified by glutathione-agarose affinity chromatography, and the collection of expressed cGST classes of each bivalve were identified using a proteomic approach. All the purified extracts were also characterized kinetically. Results reveal variations in cGST subunits collection (diversity and properties between the three tested bivalves. Using proteomics, four pi-class and two sigma-class GST subunits were identified in M. galloprovincialis. C. fluminea also yielded four pi-class and one sigma-class GST subunits. For A. cygnea, two mu-class and one pi-class GST subunits were identified, these being the first record of GSTs from these freshwater mussels. The affinity purified extracts also show differences regarding enzymatic behavior among species. The variations found in cGST collection and kinetics might justify diverse selective advantages for each bivalve organism.

  9. Ultrasound synergized with three-phase partitioning for extraction and separation of Corbicula fluminea polysaccharides and possible relevant mechanisms.

    Science.gov (United States)

    Yan, Jing-Kun; Wang, Yao-Yao; Qiu, Wen-Yi; Wang, Zhen-Bin; Ma, Haile

    2018-01-01

    Ultrasound and three-phase partitioning (USTPP) were combined to extract and separate polysaccharides (PS) efficiently from Corbicula fluminea crude extracts. The following optimum experimental conditions were established: 20% (w/v) ammonium sulfate concentration, 1:1 (v/v) t-butanol to crude extract ratio, 180W ultrasonic power, 40kHz frequency, 100% duty cycle, 10min irradiation time, and 35°C. The maximum extraction yield of PS obtained from USTPP was approximately 11.22%, which was higher than the maximum yields from conventional three-phase partitioning (TPP; 9.32%) and ultrasound extraction (USE; 6.05%). The extraction time for USTPP was significantly reduced to 10min from 30 and 60min for TPP and USE methods, respectively. The primary chemical structures of PS collected through the three extraction protocols were basically conserved. The synergistic effects of ultrasound and TPP on PS extraction were also determined. Results revealed that USTPP is an effective technique to extract and separate PS from C. fluminea potentially applied in food, cosmetics, and medicines. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Early defense responses in the freshwater bivalve Corbicula fluminea exposed to copper and cadmium: Transcriptional and histochemical studies.

    Science.gov (United States)

    Bigot, Aurélie; Minguez, Laëtitia; Giambérini, Laure; Rodius, François

    2011-11-01

    The aim of the present study was to measure the early effects of copper (10 and 50 μg L(-1)), cadmium (2, 10, and 50 μg L(-1)) and mixtures of these metals in the freshwater bivalve Corbicula fluminea exposed for 12 h in laboratory. Transcription levels of superoxide dismutase (SOD), catalase (CAT), selenium-dependent glutathione peroxidase (Se-GPx), pi-class glutathione S-transferase (pi-GST), metallothionein (MT) in digestive gland and gills, and response of lysosomal system and neutral lipids in digestive gland were determined after the exposure period. Results showed that lysosomal system, neutral lipids content, and mRNA levels were modified, suggesting their early response against oxidative stress and their important role in cell integrity. The integrated biomarker response was calculated and showed that the effects of the combinations of Cu and Cd on the biomarker responses are additive. MT and pi-GST mRNA expression correspond to the largest ranges of response. As efficient biomarkers should have an early warning capacity, SOD, CAT, Se-GPx, pi-GST, MT transcripts levels, lysosomal system, and neutral lipids could be used as biomarkers of metal contamination in the aquatic environment. Copyright © 2010 Wiley Periodicals, Inc.

  11. Proteomic profiling of cytosolic glutathione transferases from three bivalve species: Corbicula fluminea, Mytilus galloprovincialis and Anodonta cygnea.

    Science.gov (United States)

    Martins, José Carlos; Campos, Alexandre; Osório, Hugo; da Fonseca, Rute; Vasconcelos, Vítor

    2014-01-27

    Suspension-feeding bivalves are considered efficient toxin vectors with a relative insensitivity to toxicants compared to other aquatic organisms. This fact highlights the potential role of detoxification enzymes, such as glutathione transferases (GSTs), in this bivalve resistance. Nevertheless, the GST system has not been extensively described in these organisms. In the present study, cytosolic GSTs isoforms (cGST) were surveyed in three bivalves with different habitats and life strategies: Corbicula fluminea, Anodonta cygnea and Mytilus galloprovincialis. GSTs were purified by glutathione-agarose affinity chromatography, and the collection of expressed cGST classes of each bivalve were identified using a proteomic approach. All the purified extracts were also characterized kinetically. Results reveal variations in cGST subunits collection (diversity and properties) between the three tested bivalves. Using proteomics, four pi-class and two sigma-class GST subunits were identified in M. galloprovincialis. C. fluminea also yielded four pi-class and one sigma-class GST subunits. For A. cygnea, two mu-class and one pi-class GST subunits were identified, these being the first record of GSTs from these freshwater mussels. The affinity purified extracts also show differences regarding enzymatic behavior among species. The variations found in cGST collection and kinetics might justify diverse selective advantages for each bivalve organism.

  12. Micro-structure and chemical composition of vateritic deformities occurring in the bivalve Corbicula fluminea (Müller, 1774).

    Science.gov (United States)

    Frenzel, Max; Harper, Elizabeth M

    2011-05-01

    Vateritic deformities occurring in the invasive heterodont bivalve Corbicula fluminea from several locations in the UK were characterised in detail for the first time using scanning electron microscopy, X-ray diffraction and different geochemical techniques (electron microprobe, ICP-AES, and mass spectrometry). Large volumes of vaterite are produced abnormally in the animals' shells in the form of yellow-green bulges. These are distinguished from the aragonitic parts of the shell by their characteristic micro-structures, content of organic material, trace elemental composition and carbon stable isotope signatures. The most commonly observed micro-structures include columnar vaterite, lamellar vaterite and different irregular structures occurring in all parts of the shell. There are indications that organic material is present largely as intracrystalline impurities or nano-scale phases and not as envelopes around microstructural units. These micro-structures are novel, nothing equivalent having yet been described for other vateritic systems. Euhedral vaterite crystals also occur occasionally. The vaterite has generally higher Mg/Ca and lower Na/Ca, K/Ca than the aragonite. In addition, δ¹³C is also always lower. Microstructural characteristics would suggest loss of biological control probably due to physiological stress(es) inducing the switch to vaterite production. The vaterite might be stabilised by its higher content of organic material and magnesium. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. The effectiveness of domestic cook on inactivation of murine norovirus in experimentally infected Manila clams (Ruditapes philippinarum).

    Science.gov (United States)

    Toffan, A; Brutti, A; De Pasquale, A; Cappellozza, E; Pascoli, F; Cigarini, M; Di Rocco, M; Terregino, C; Arcangeli, G

    2014-01-01

    The aim of this work was to evaluate the efficacy of domestic cooking in inactivating Manila clams experimentally infected with murine norovirus (MNV). A cooking pan was modified to enable electronic temperature probes to be positioned to record both flesh and environment temperature. Manila clams were infected with 10(4) TCID 50% ml(-1) of MNV. The infected whole-in-shell clams, divided into three replicates, were cooked on an electric stove, and groups of nine clams were removed from the pan at fixed intervals. Pools of three digestive glands were examined by virus isolation to ascertain residual viral load. Results showed that 10 min of cooking by a traditional domestic method at a temperature close to 100°C, for at least 2 min, can completely devitalize the MNV in infected clams. This is generally the time needed for the majority of valves to open up. At present, it is highly recommended to label all lagoon products as 'requiring cooking before consumption', but no specifications are given on how long and at what temperature they should be cooked. Our results can provide the consumer with useful indications on how to cook clams to prevent any risk of foodborne illness. © 2013 The Society for Applied Microbiology.

  14. Protein expression profiling in haemocytes and plasma of the Manila clam Ruditapes philippinarum in response to infection with Perkinsus olseni.

    Science.gov (United States)

    Fernández-Boo, S; Villalba, A; Cao, A

    2016-11-01

    The protein expression profiling in clam haemocytes and plasma in response to Perkinsus olseni was addressed. Adult Manila clams from a P. olseni-free bed were experimentally challenged with parasite zoospores to analyse immune response. In another experiment, the effects of longer term infection were assessed in adult clams collected from a P. olseni-affected bed, by comparing moderate to very heavily infected clams with non-infected ones. Haemocyte and plasma proteins were separated by two-dimensional electrophoresis; spot patterns were qualitatively compared between treatments within each experiment and the spots indicating differential protein expression associated with P. olseni challenge or with field infection were processed for protein identification. Fifteen clam proteins (four in haemocytes and eleven in plasma) of which expression was markedly affected by P. olseni were identified. Some of the identified proteins have a well-known role in clam immune response against the parasite, such as lysozyme and lectins. Rho GTPase-activating protein 6 could be a marker of resistance against P. olseni, which should be further studied. © 2016 John Wiley & Sons Ltd.

  15. Occurrence and Seasonal Variations of Lipophilic Marine Toxins in Commercial Clam Species along the Coast of Jiangsu, China.

    Science.gov (United States)

    Wang, Xin-Zhi; Cheng, Ying; Li, Na; Wen, Hong-Mei; Liu, Rui; Shan, Chen-Xiao; Chai, Chuan; Wu, Hao

    2015-12-25

    Recent studies have examined lipophilic marine toxins (LMTs) in shellfish and toxic algae worldwide, but the occurrence and seasonal variations of LMTs in commercial clams (including Mactra veneriformis, Ruditapes philippinarum, Meretrix meretrix, and Cyclina sinensis) at their major culturing area in Jiangsu, China, remain largely unexplored. In this study, a new solid phase extraction (SPE) in combination with an ultra-fast liquid chromatography and triple-quadrupole linear ion trap mass spectrometry (UFLC-TQ-MS) method was developed to determine the presence of 10 typical LMTs (okadaic acid (OA), yessotoxins (YTXs), azaspiracids (AZA1-3), pectenotoxins (PTX2), gymnodimine (GYM), dinophysistoxins (DTX1&2), and spirolides (SPX1)) in the aforementioned four clam matrices. After confirmation of its sensitivity and precision, this method was used to evaluate the amounts of LMTs in clam samples harvested in five aquaculture zones of the Jiangsu coastal area. Monthly variations of GYM, PTX2, OA, and DTX1&2 in 400 clam samples from the sample areas were determined from January 2014 through August 2015. Peak values were observed during May and August. This is the first systematic report of LMTs detected in clam samples harvested in Jiangsu. Follow-up research and the implementation of protective measures are needed to ensure the safety of clams harvested in this area.

  16. De novo RNA-Seq analysis of the venus clam, Cyclina sinensis, and the identification of immune-related genes.

    Science.gov (United States)

    Pan, Baoping; Ren, Yipeng; Gao, Jing; Gao, Hong

    2015-01-01

    The Venus clam, Cyclina sinensis, is one of the most important bivalves in China. In recent years, increasing expansive morbidity has occurred in breeding areas, imposing significant losses on the national economy. To understand the molecular mechanisms of immune-related genes, we analyzed and sequenced hemolymph samples that were injected with two pathogenic microorganisms using the Illumina Miseq system. After trimming, more than 12 M PE reads with an average length greater than 410 bp were assembled into 70,079 transcripts with a mean length of 980 bp. Using a homology analysis, 102 (135 transcripts) potentially immune-related genes were identified, and most of them exhibited a similar pattern in both samples. These data indicated that the response of the clam to both types of bacterial infection might follow a similar molecular mechanism. Using the TreeFam method, 9,904 gene families and 1,031 unique families of the clam were preliminarily classified in comparison to five related species. A significant number of SSRs were identified, which could facilitate the identification of polymorphisms in Venus clam populations. These datasets will improve our knowledge of the molecular mechanisms driving the immune response to bacterial infection in clam populations and will provide basic data about clam breeding and disease control.

  17. Effects of benzo(a)pyrene on differentially expressed genes and haemocyte parameters of the clam Venerupis philippinarum.

    Science.gov (United States)

    Liu, Na; Pan, Luqing; Gong, XiaoLi; Tao, Yanxia; Hu, Yanyan; Miao, Jingjing

    2014-03-01

    In this study a suppression subtractive hybridisation method was employed to identify differentially expressed genes of the clam Venerupis philippinarum exposed to benzo(a)pyrene (BaP). Nineteen known transcripts and seven predicted proteins were found from the subtractive cDNA library of the clam, which could provide more sequence information for further study. Seven of the differentially expressed genes were selected for mRNA expression analysis. Real-time PCR analysis revealed that the expression level of the selected cDNAs of clams was up-regulated to varying degrees by different concentration of BaP. They are suggested as potential molecular biomarkers for polycyclic aromatic hydrocarbons (PAHs) pollution monitoring in aquatic ecosystems. In addition, haemocyte parameters were also measured, and a decrease of total haemocyte counts and suppression of antibacterial and bacteriolytic activities were detected in BaP-stressed clams. We suggest that the modulation of the expression of the selected genes caused by PAHs probably leads to the disturbance of the immune defense of the clam. Meanwhile, the adverse effects of PAHs on haemocyte parameters caused the suppression of the immune defense and susceptibility to infectious diseases. Therefore, it is inferred that PAHs pollutants could interact with components of the immune system and interferes with defense functions of the clam V. philippinarum.

  18. De novo RNA-Seq analysis of the venus clam, Cyclina sinensis, and the identification of immune-related genes.

    Directory of Open Access Journals (Sweden)

    Baoping Pan

    Full Text Available The Venus clam, Cyclina sinensis, is one of the most important bivalves in China. In recent years, increasing expansive morbidity has occurred in breeding areas, imposing significant losses on the national economy. To understand the molecular mechanisms of immune-related genes, we analyzed and sequenced hemolymph samples that were injected with two pathogenic microorganisms using the Illumina Miseq system. After trimming, more than 12 M PE reads with an average length greater than 410 bp were assembled into 70,079 transcripts with a mean length of 980 bp. Using a homology analysis, 102 (135 transcripts potentially immune-related genes were identified, and most of them exhibited a similar pattern in both samples. These data indicated that the response of the clam to both types of bacterial infection might follow a similar molecular mechanism. Using the TreeFam method, 9,904 gene families and 1,031 unique families of the clam were preliminarily classified in comparison to five related species. A significant number of SSRs were identified, which could facilitate the identification of polymorphisms in Venus clam populations. These datasets will improve our knowledge of the molecular mechanisms driving the immune response to bacterial infection in clam populations and will provide basic data about clam breeding and disease control.

  19. Clam focal and systemic immune responses to QPX infection revealed by RNA-seq technology.

    Science.gov (United States)

    Wang, Kailai; del Castillo, Carmelo; Corre, Erwan; Pales Espinosa, Emmanuelle; Allam, Bassem

    2016-02-27

    The hard clam Mercenaria mercenaria is an important seafood species widely exploited along the eastern coasts of the United States and play a crucial role in coastal ecology and economy. Severe hard clam mortalities have been associated with the protistan parasite QPX (Quahog Parasite Unknown). QPX infection establishes in pallial organs with the lesions typically characterized as nodules, which represent inflammatory masses formed by hemocyte infiltration and encapsulation of parasites. QPX infection is known to induce host changes on both the whole-organism level and at specific lesion areas, which imply systemic and focal defense responses, respectively. However, little is known about the molecular mechanisms underlying these alterations. RNA-seq was performed using Illumina Hiseq 2000 (641 Million 100 bp reads) to characterize M. mercenaria focal and systemic immune responses to QPX. Transcripts were assembled and the expression levels were compared between nodule and healthy tissues from infected clams, and between these and tissues from healthy clams. De novo assembly reconstructed a consensus transcriptome of 62,980 sequences that was functionally-annotated. A total of 3,131 transcripts were identified as differentially expressed in different tissues. Results allowed the identification of host immune factors implicated in the systemic and focal responses against QPX and unraveled the pathways involved in parasite neutralization. Among transcripts significantly modulated upon host-pathogen interactions, those involved in non-self recognition, signal transduction and defense response were over-represented. Alterations in pathways regulating hemocyte focal adhesion, migration and apoptosis were also demonstrated. Our study is the first attempt to thoroughly characterize M. mercenaria transcriptome and identify molecular features associated with QPX infection. It is also one of the first studies contrasting focal and systemic responses to infections in

  20. Potential for Introduction of Invasive Species into Louisiana from Illinois River Dredged Material

    Science.gov (United States)

    2008-06-01

    Although not collected in the aforementioned surveys, the zebra mussel (Dreissena polymorpha) and the Asian clam ( Corbicula fluminea ) do occur in the...Sarotherodon, or Tilapia Tilapia Fish Tinca tinca Tench Mammals Myocastor coypus Nutria Mammals Sus scrofa Feral hog Mollusks Corbicula fluminea Asian...Oreochromis, Sarotherodon Tilapia Finfish PA Corbicula fluminea Asian clam Mollusk EE Dreissena polymorpha Zebra mussel Mollusk EE Perna perna Brown mussel

  1. In vivo exposure of the marine clam Ruditapes philippinarum to zinc oxide nanoparticles: responses in gills, digestive gland and haemolymph.

    Science.gov (United States)

    Marisa, Ilaria; Matozzo, Valerio; Munari, Marco; Binelli, Andrea; Parolini, Marco; Martucci, Alessandro; Franceschinis, Erica; Brianese, Nicola; Marin, Maria Gabriella

    2016-08-01

    Potential nanoparticle (NP) toxicity poses a growing concern in marine coastal environments. Among NPs, zinc oxide nanoparticles (nZnO) are widely used in many common products that ultimately become deposited in coastal habitats from multiple non-point sources. In this study, we evaluated the in vivo effects of nZnO in the clam Ruditapes philippinarum. Animals were exposed to nZnO (1 and 10 μg/L) and ZnCl2 (10 μg/L) for 7 days. ZnCl2 was used to compare the effects of the NPs to those of Zn(2+) and to ascertain whether nZnO toxicity is attributable to the release of ions into the aquatic medium. At differing time intervals during the exposure, several biochemical and cellular responses were evaluated in the clam gills, digestive gland, and haemolymph. The results showed that nZnO, at concentrations close to the predicted environmental levels, significantly affected various parameters in clam tissues. Significant increases in catalase and superoxide dismutase activities and a decreasing trend of glutathione S-transferase activity indicated the involvement of oxidative stress in nZnO toxicity. In clams exposed to ZnCl2, slight variations in antioxidant enzyme activities were detected with respect to nZnO-treated clams. However, no damage to lipids, proteins or DNA was revealed in all exposure conditions, suggesting a protection of antioxidant enzymes in the tissues. Of the various haemolymph parameters measured, haemocyte proliferation increased significantly, in ZnCl2-treated clams in particular. Under nZnO (10 μg/L) and ZnCl2 exposure, DNA damage in haemocytes was also revealed, but it was lower in clams exposed to ZnCl2. A decreasing trend in gill AChE activity of treated clams proposed a possible role of zinc ions in nZnO toxicity. However, the dissimilar modulation of the responses in the nZnO- and ZnCl2-exposed clams suggested different mechanisms of action, with nZnO toxicity possibly depending not only on the release of zinc ions but also on NP

  2. 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

  3. Tensile properties of CLAM steel irradiated up to 20.1 dpa in STIP-V

    Science.gov (United States)

    Ge, Hongen; Peng, Lei; Dai, Yong; Huang, Qunying; Ye, Minyou

    2016-01-01

    Specimens of China low activation martensitic steel (CLAM) were irradiated in the fifth experiment of SINQ Target Irradiation Program (STIP-V) up to 20.1 dpa/1499 appm He/440 °C. Tensile tests were performed at room temperature (R.T) and irradiation temperatures (Tirr) in the range of 25-450 °C. The tensile results demonstrated strong effect of irradiation dose and irradiation temperature on hardening and embrittlement. With Tirr below ˜314 °C, CLAM steel specimens tested at R.T and Tirr showed similar evolution trend with irradiation dose, compared to other reduced activation ferritic/martensitic (RAFM) steels in similar irradiation conditions. At higher Tirr above ˜314 °C, it is interesting that the hardening effect decreases and the ductility seems to recover, probably due to a strong effect of high irradiation temperature.

  4. Creep deformation and rupture behavior of CLAM steel at 823 K and 873 K

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Boyu [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Bo, E-mail: bo.huang@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Li, Chunjing; Liu, Shaojun; Xu, Gang [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Zhao, Yanyun; Huang, Qunying [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); University of Science and Technology of China, Hefei, Anhui 230027 (China)

    2014-12-15

    China Low Activation Martensitic (CLAM) steel is selected as the candidate structural material in Fusion Design Study (FDS) series fusion reactor conceptual designs. The creep property of CLAM steel has been studied in this paper. Creep tests have been carried out at 823 K and 873 K over a stress range of 150–230 MPa. The creep curves showed three creep regimes, primary creep, steady-state creep and tertiary creep. The relationship between minimum creep rate (ε-dot{sub min}) and the applied stress (σ) could be described by Norton power law, and the stress exponent n was decreased with the increase of the creep temperature. The creep mechanism was analyzed with the fractographes of the rupture specimens which were examined by scanning electron microscopy (SEM). The coarsening of precipitates observed with transmission electron microscope (TEM) indicated the microstructural degradation after creep test.

  5. He and H irradiation effects on the nanoindentation hardness of CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Siben [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Peng, Lei, E-mail: penglei@ustc.edu.cn [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Ge, Hongen [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Qunying; Xin, Jingping [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Zhao, Ziqiang [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)

    2014-12-15

    In this study, He and H ion irradiation induced hardening behavior of China Low Activation Martensitic (CLAM) steel was investigated, and the influence of Si on irradiation hardening was also examined. CLAM steel with different Si contents, Heat 0912 and Heat 0408D, were irradiated with single He (He concentration range from 0 to 2150 appm) ion beam and He/H dual ion beams. Then nanoindentation tests were applied to evaluate the ion irradiation induced hardening effect. The result of Heat 0912 showed hardening effect would be more serious with higher He concentration, and the trend saturated when He concentration reach 1000 appm. Comparing the result of Heat 0912 and Heat 0408D, higher Si content might improve the resistance to hardening.

  6. Relationships between intertidal clam population and health status of the soft-shell clam Mya arenaria in the St. Lawrence Estuary and Saguenay Fjord (Québec, Canada).

    Science.gov (United States)

    Gagné, F; Blaise, C; Pellerin, J; Fournier, M; Durand, M J; Talbot, A

    2008-01-01

    The purpose of this study was to examine the impacts of anthropogenic activity on the health status of intertidal clam populations of the Saguenay Fjord and the St. Lawrence Estuary (Québec, Canada). Clams were collected during low tide at sites subject to direct contamination and at sites far from human activity. Clams were analyzed for tributyltin and dibutyltin total levels and toxic stress (glutathione S-transferase, gonadal lipid peroxidation and DNA strand breaks), immunocompetence (phagocytic activity, hemocyte count and viability), reproduction (gonado-somatic index, gamete maturation, and vitellogenin-like proteins), energy status (temperature-dependent mitochondrial electron transport, and gonad lipids), and individual status (age, condition factor, and growth index). These responses were compared against population characteristics such as live clam density, number of empty shells, and sex ratio. The results show that clam density decreased with distance from the estuary (high salinity level) to upstream of the fjord (low salinity). There was no clear relationship between the number of empty shells and distance or site quality. Clam density values corrected against distance were significantly correlated with hemocyte viability, phagocytic activity, mitochondrial electron transport (MET), DNA damage in gonad, and temperature-dependent mitochondrial electron transport activity. A canonical analysis of the various groups of biomarkers revealed that population metrics were more strongly related with immunocompetence, followed by energy status and temperature-dependent mitochondrial electron transport activity. However, toxic stress biomarkers were strongly associated with energy status and reproduction. This was further confirmed by non-linear modeling using adaptive artificial neural networks (genetic selection and back propagation learning paradigms), where the following parameters were able to predict population parameters with salinity), where

  7. Dual roles of p82, the clam CPEB homolog, in cytoplasmic polyadenylation and translational masking.

    Science.gov (United States)

    Minshall, N; Walker, J; Dale, M; Standart, N

    1999-01-01

    In the transcriptionally inert maturing oocyte and early embryo, control of gene expression is largely mediated by regulated changes in translational activity of maternal mRNAs. Some mRNAs are activated in response to poly(A) tail lengthening; in other cases activation results from de-repression of the inactive or masked mRNA. The 3' UTR cis-acting elements that direct these changes are defined, principally in Xenopus and mouse, and the study of their trans-acting binding factors is just beginning to shed light on the mechanism and regulation of cytoplasmic polyadenylation and translational masking. In the marine invertebrate, Spisula solidissima, the timing of activation of three abundant mRNAs (encoding cyclin A and B and the small subunit of ribonucleotide reductase, RR) in fertilized oocytes correlates with their cytoplasmic polyadenylation. However, in vitro, mRNA-specific unmasking occurs in the absence of polyadenylation. In Walker et al. (in this issue) we showed that p82, a protein defined as selectively binding the 3' UTR masking elements, is a homolog of Xenopus CPEB (cytoplasmic polyadenylation element binding protein). In functional studies reported here, the elements that support polyadenylation in clam egg lysates include multiple U-rich CPE-like motifs as well as the nuclear polyadenylation signal AAUAAA. This represents the first detailed analysis of invertebrate cis-acting cytoplasmic polyadenylation signals. Polyadenylation activity correlates with p82 binding in wild-type and CPE-mutant RR 3' UTR RNAs. Moreover, since anti-p82 antibodies specifically neutralize polyadenylation in egg lysates, we conclude that clam p82 is a functional homolog of Xenopus CPEB, and plays a positive role in polyadenylation. Anti-p82 antibodies also result in specific translational activation of masked mRNAs in oocyte lysates, lending support to our original model of clam p82 as a translational repressor. We propose therefore that clam p82/CPEB has dual functions in

  8. 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.

    a stage with a digestive tract. Metamorphosis represents the next phase of development, where stored energy reserves are consumed for metabolism during early development (Whyte, Bourne & Hodgson1990). Energy reserves are accumulated by the planktonic... and Gopinathan (2004b) evaluated the optimum salinity and pH requirements for larval survival, growth and metamorphosis. However, informationonthe energy metabolism of early development in the short neck clam is lacking. The objective of this study...

  9. Cloning and localization of MCdef, a defensin from Manila clams (Ruditapes philippinarum).

    Science.gov (United States)

    Adhya, Mausumi; Jeung, Hee-Do; Kang, Hyun-Sil; Choi, Kwang-Sik; Lee, Dong Sun; Cho, Moonjae

    2012-01-01

    A defensin-like peptide was previously detected in hemocytes of Manila clams (Ruditapes philippinarum). In the current study, we cloned and characterized this defensin, designated MCdef. Cloning produced a full-length gene sequence of 201 bp predicted to encode a 66-amino-acid precursor protein maturing to a 44-amino-acid residue. Amino acid sequence analysis showed that MCdef is similar to defensins from marine mollusks and ticks. Phylogenetic analysis suggested that MCdef is closely related to defensins from Mytilus galloprovincialis (Mediterranean mussel) and Crassostrea gigas (Pacific cupped oyster). The three-dimensional structure of MCdef was modeled using the solution structure of C. gigas defensin as a template. With the exception of three variable loop areas, the modeled structure of MCdef was identical to that of C. gigas defensin. MCdef antiserum was raised against a synthetic MCdef peptide and verified by Western blotting using recombinant MCdef. RT-PCR analysis demonstrated high levels of MCdef mRNA in hemocytes and adductor, foot, gill, mantle, palp, and siphon tissues of Vibrio tapetis-infected Manila clams, whereas in V. tapetis-uninfected Manila clams, the level of MCdef mRNA was low in adductor, palp, and siphon tissues and even lower in the other tested tissues. Immunohistochemical analysis revealed high MCdef expression was detected in the gill, the mantle, and the digestive tubules of the diverticulum of V. tapetis-infected Manila clams. Minimum inhibitory concentration (MIC) of the purified rMCdef was determined. MCdef showed highest activity against Streptococcus iniae and Staphylococcus aureus. Copyright © 2011 Elsevier Inc. All rights reserved.

  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. Effect of tantalum content on microstructure and tensile properties of CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Xiangwei [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); University of Science and Technology of China, Hefei, Anhui 230027 (China); Liu, Shaojun, E-mail: shaojun.liu@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Zhao, Yanyun [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2016-03-15

    Highlights: • With the increase of Ta content, the grain size decreased firstly, and then leveled off when Ta content was higher than 0.15 wt%. • The content of Ta-riched MX particles increased with Ta content increasing, and the Cr-riched M{sub 23}C{sub 6} carbides reversed. • CLAM steel with Ta content of 0.027 wt% had the highest strength, but the difference in strength of the four ingots was little. - Abstract: Four ingots of China Low Activation Martensitic (CLAM) steel with different Tantalum (Ta) contents of 0.027 wt%, 0.078 wt%, 0.15 wt% and 0.18 wt%, respectively, were produced by vacuum induction furnace. Microstructure observation and tensile tests were performed to make clear the effect of Ta content on the microstructure and properties of CLAM steel. Experimental results showed that the content of Ta-riched MX particles increased with Ta content increasing from 0.027 wt% to 0.18 wt%, and the Cr-riched M{sub 23}C{sub 6} carbides reversed. Meanwhile, the grain size became finer with the increase of Ta content. However, the effect of Ta content on grain size refinement weakened when Ta content was higher than 0.15 wt% in this study. Both the grain size and precipitates could affect the tensile properties of the four ingots. The precipitation strengthening of Cr-riched M{sub 23}C{sub 6} carbides was considered to be the main possible reason that CLAM steel with Ta content of 0.027 wt% had the highest strength. In general, there was little difference in strength of the four ingots with the change of Ta content.

  12. 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 (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.

  13. The influence of different microalgal diets on European clam (Ruditapes decussatus, Linnaeus, 1758) larvae culture performances

    OpenAIRE

    Matias, D.; R. Ben-Hamadou; Joaquim, S.; Matias, A. M.; Sobral, P. (Paula); Leitão, A.

    2015-01-01

    The European clam, Ruditapes decussatus is a species with high commercial importance in Portugal and other Southern European countries. However, the development of R. decussatus culture has been limited by the highly variable patterns of natural recruitment. The development of hatchery technology will provide an alternative source of spat. The effect of six nutritional regimes on the survival, growth and biochemical composition of R. decussatus larvae were evaluated, aiming to provide crucial...

  14. 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...

  15. Effect of weld spacing on microstructure and mechanical properties of CLAM electron beam welding joints

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Yutao; Huang, Bo, E-mail: aufa0007@163.com; Zhang, Junyu; Zhang, Baoren; Liu, Shaojun; Huang, Qunying

    2016-11-15

    Highlights: • The welded joints of CLAM steel with different weld spacings have been fabricated with electron beam welding, and a simplified model of CLAM sheet was proposed. • The microstructure and mechanical properties such as microhardness, impact and tensile were investigated at different welding spacing for both conditions of as-welded and post weld heat treatment (PWHT). • The effect of the welding thermal cycle was significantly when the weld spacings were smaller than 4 mm. • When the weld spacing was small enough, the original microstructures would be fragmented with the high heat input. - Abstract: China low activation martensitic (CLAM) steel has been chosen as the primary structural material in the designs of dual function lithium-lead (DFLL) blanket for fusion reactors, China helium cooled ceramic breeder (HCCB) test blanket module (TBM) for ITER and China fusion engineering test reactor (CFETR) blanket. The cooling components of the blankets are designed with high density cooling channels (HDCCs) to remove the high nuclear thermal effectively. Hence, the welding spacing among the channels are small. In this paper, the welded joints of CLAM steel with different weld spacings have been fabricated with electron beam welding (EBW). The weld spacing was designed to be 2 mm, 3 mm, 4 mm, 6 mm and 8 mm. The microstructure and mechanical properties such as microhardness, impact and tensile were investigated at different welding spacing for both conditions of as-welded and post weld heat treatment (PWHT). The PWHT is tempering at 740 °C for 120 min. The results showed that the grain size in the heat affected zone (HAZ) increased with the increasing weld spacing, and the joint with small weld spacing had a better performance after PWHT. This work would give useful guidance to improve the preparation of the cooling components of blanket.

  16. Universal Virus Adsorption on Inert Particles Utilizing the Coated Latex Adsorption Method (CLAM)

    Science.gov (United States)

    1975-06-30

    ANALYSIS FOR CLAM SYSTEM AUTOMATION Automated image analysis can provide a rapid means of identifying and quantifying large amounts of pictorial information...J. L. Binet, C. Dereusefond and Y. Biozzi. 1970. Etude de la response immunologique an niverau cellulaire . I. Identification des cellules...preliminary rough screening process. 7. Automation of the process appears to be quite feasible with the major biological steps well defined in terms of

  17. 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.

  18. 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.

  19. Role of neuropeptide F in regulating filter feeding of Manila clam, Ruditapes philippinarum.

    Science.gov (United States)

    Wang, Xin; Miao, Jingjing; Liu, Peipei; Pan, Luqing

    2017-03-01

    Endogenous signals which may be involved in the regulation of filter feeding in bivalves have never been examined. NPY/NPF homologue has been proved to play an important role in the regulation of food intake in vertebrate and several invertebrates. In this study, a NPF homologue was cloned from visceral ganglia of clam Ruditapes philippinarum. The full-length cDNA sequence was 892bp in length and encoded a precursor of 82 amino acid residues. We then examined the effects of fasting and refeeding on the filtration rates (FR), plasma glucose concentration (PGC), 5-HT, DA and the expression level of the rp-NPF and insulin transcript. The mRNA expression level of rp-NPF in visceral ganglion was increased during fasting, and rose to highest level on 72h after starvation and declined immediately after food had been supplied. Hemocoel injection of rp-NPF(5μg/g)significantly increased FR of clams within 2h. Compared to the controls, a significant increase in insulin mRNA levels was observed at 8h after injection. Contents of 5-HT and DA also increased in the 5μg/grp-NPF administrated clams at 8 and 24h after injection. These results suggest that, similar to vertebrates, NPF, insulin, 5-HT and DA may play a role in the regulation of feeding in R. philippinarum. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Population genetics of the Manila clam (Ruditapes philippinarum) introduced in North America and Europe.

    Science.gov (United States)

    Cordero, David; Delgado, Marina; Liu, Baozhong; Ruesink, Jennifer; Saavedra, Carlos

    2017-01-03

    Globally, the Manila clam (Ruditapes philippinarum) stands as the second most important bivalve species in fisheries and aquaculture. Native to the Pacific coast of Asia, it is now well-established in North America and Europe, where its on-going management reflects local economic interests. The historic record of transfers spans the 20th century and suggests sequential movement from Japan to North America, as a hitch-hiker on oysters, and then intentional introduction in Europe, but global genetic data are missing. We have studied mitochondrial DNA and microsatellite markers in nine populations from Asia, North America and Europe. The results from the two types of markers indicated a good concordance of present-day genetic structure with the reported history of clam transfers across continents, and no evidence of relevant concealed introductions from continental Asia in Europe and North America. However, European populations showed a loss of genetic variability and significant genetic differentiation as compared to their American counterparts. Our study shows that in spite of the increasing ease for species to spread out of their native range, in the case of the Manila clam this has not resulted in new invasion waves in the two studied continents.

  1. Effect of Tantalum content on the low cycle fatigue properties of CLAM steel at 823 K

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Xiangwei [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); University of Science and Technology of China, Hefei, Anhui, 230027 (China); Liu, Shaojun, E-mail: shaojun.liu@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); Zhao, Yanyun; Wang, Kun [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China)

    2017-01-15

    Highlights: • The fatigue life initially decreased and then increased as the Ta content was increased from 0.027 wt% to 0.18 wt%. • The softening rate had declined with Ta content increased and the reduced softening rate was attributed to the increased number of Ta-rich MX particles. • The grain size and M{sub 23}C{sub 6} were closely associated with the Ta content. • The crack distribution was quite sensitive to the Ta content. - Abstract: The effect of tantalum (Ta) content on the low cycle fatigue (LCF) properties of CLAM steel at 823 K was investigated in this paper. Low cycle fatigue tests were carried out on four ingots of CLAM steel with Ta contents of 0.027 wt%, 0.078 wt%, 0.15 wt% and 0.18 wt%, respectively. The results showed that the fatigue life and softening behavior of CLAM steel were influenced by Ta content. The fatigue life initially decreased and then increased as the Ta content was increased from 0.027 wt% to 0.18 wt%. The softening rate had declined with Ta content increased and the reduced softening rate was attributed to the increased number of Ta-rich MX particles.

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

    Science.gov (United States)

    Hanana, Houda; Talarmin, Hélène; Pennec, Jean-Pierre; Droguet, Mickael; Morel, Julie; Dorange, Germaine

    2012-12-15

    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. Changes in fatty acid composition in the giant clam Tridacna maxima in response to thermal stress

    Directory of Open Access Journals (Sweden)

    Vaimiti Dubousquet

    2016-10-01

    Full Text Available Temperature can modify membrane fluidity and thus affects cellular functions and physiological activities. This study examines lipid remodelling in the marine symbiotic organism, Tridacna maxima, during a time series of induced thermal stress, with an emphasis on the morphology of their symbiont Symbiodinium. First, we show that the French Polynesian giant clams harbour an important proportion of saturated fatty acids (SFA, which reflects their tropical location. Second, in contrast to most marine organisms, the total lipid content in giant clams remained constant under stress, though some changes in their composition were shown. Third, the stress-induced changes in fatty acid (FA diversity were accompanied by an upregulation of genes involved in lipids and ROS pathways. Finally, our microscopic analysis revealed that for the giant clam's symbiont, Symbiodinium, thermal stress led to two sequential cell death processes. Our data suggests that the degradation of Symbiodinium cells could provide an additional source of energy to T. maxima in response to heat stress.

  4. The association between razor clam consumption and memory in the CoASTAL cohort.

    Science.gov (United States)

    Grattan, Lynn M; Boushey, Carol; Tracy, Kate; Trainer, Vera L; Roberts, Sparkle M; Schluterman, Nicolas; Morris, J Glenn

    2016-07-01

    This study represents a preliminary effort to examine the potential impacts of chronic, low level domoic acid (DA) exposure on memory in the CoASTAL cohort over the first four years of data collection (Wave 1). Five hundred and thirteen adult men and women representing three Native American Tribes were studied annually with standard measures of cognition and razor clam consumption (a known vector of DA exposure) over a four-year period. In addition, a pilot metric of DA concentration exposure was used which took into consideration average DA concentration levels in source beaches, as well as the amount consumed. Based upon generalized estimating equations (GEE) analysis, controlling for age, sex, race, year, education level, tribe, and employment status, findings indicated that high razor clam consumers (15 or more per month) had isolated decrements on some measures of memory (p=0.02-0.03), with other cognitive functions unaffected. The relatively lower memory scores were still within normal limits, and were thus not clinically significant. The pilot DA exposure metric had no association with any other aspect of cognition or behavior. There is a possible association between long-term, low-level exposure to DA through heavy razor clam consumption and memory functioning. Copyright © 2016. Published by Elsevier B.V.

  5. Molecular diversity and evolution of defensins in the manila clam Ruditapes philippinarum.

    Science.gov (United States)

    Wang, Qing; Zhang, Linbao; Yang, Dinglong; Yu, Qian; Li, Fei; Cong, Ming; Ji, Chenglong; Wu, Huifeng; Zhao, Jianmin

    2015-11-01

    Four types of defensins were identified in Manila clam and designated as Rpdef1, Rpdef2, Rpdef3 and Rpdef4, which encoded a polypeptide of 49, 46, 45 and 42 amino acids, respectively. Sequence alignments indicated that Rpdef1 shared 46.9% identity with Rpdef2, 40.8% with Rpdef3, and 34.7% with Rpdef4. Analysis of transcript polymorphism showed that Rpdef3 accounted for about 60% frequency of Rpdefs occurrence in clams from three geographic origins (Dalian, Qingdao and Hangzhou). By quantitative real-time RT-PCR (qRT-PCR) analysis, the transcripts of Rpdefs were mainly detected in hemocytes and they responded sensitively to bacterial challenge in hemocytes. Evolutionary analysis indicated that all Rpdefs were under positive selection with positively selected basic amino acid residues detected in the C-terminal regions, which perhaps have a functional relevance by modifying the charge distribution of Rpdefs. The results also showed some lineages with dN/dS > 1, suggesting positive selection pressures existed in some lineages of phylogeny tree constructed by mollusk defensins. Overall, our results suggest that Rpdefs perhaps played important roles in host defense and positive selection is the major driving force in generating high diversity of defensins in the Manila clam. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Microstructure evolution of the oxide dispersion strengthened CLAM steel during mechanical alloying process

    Energy Technology Data Exchange (ETDEWEB)

    Song, Liangliang [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Science, Hefei, Anhui, 230031 (China); University of Science and Technology of China, Hefei, Anhui, 230031 (China); Liu, Shaojun, E-mail: shaojun.liu@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Science, Hefei, Anhui, 230031 (China); Mao, Xiaodong [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Science, Hefei, Anhui, 230031 (China)

    2016-11-15

    Highlights: • A nano-sized oxides dispersed ODS-CLAM steel was obtained by MA and HIP. • A minimum saturated grain size of down to 30 nm was achieved by varying the milling time from 0 to 100 h. • Solution of W in the MA powder could be significantly improved by increasing MA rotation speed. - Abstracts: Oxide dispersion strengthened Ferritic/Martensitic steel is considered as one of the most potential structural material for future fusion reactor, owing to its high mechanical properties and good irradiation resistance. The oxide dispersion strengthened China Low Activation Martensitic (ODS-CLAM) steel was fabricated by mechanical alloying (MA) and hot isostatic pressing (HIP). The microstructural evolutions during the process of ball milling and subsequent consolidation were investigated by SEM, XRD and TEM. The results showed that increasing the milling time during the first 36 h milling could effectively decrease the grain size to a value of around 30 nm, over which grain sized remained nearly constant. Increasing the rotation speed promoted the solution of tungsten (W) element obviously and decreased the grain size to a certain degree. Observation on the consolidated and further heat-treated ODS-CLAM steel samples indicated that a martensite microstructure with a high density of nano-particles was achieved.

  7. Biochemical biomarkers of pollution in the clam Chamaelea gallina from south-Spanish littoral.

    Science.gov (United States)

    Rodríguez-Ortega, Manuel J; Alhama, José; Funes, Victoria; Romero-Ruíz, Antonio; Rodríguez-Ariza, Antonio; López-Barea, Juan

    2002-03-01

    Fourteen biochemical pollution biomarkers were analyzed in the clam Chamaelea gallina sampled at seven South-Spanish littoral sites at different times in 1999. They included enzymes that regenerate reduced nicotinamide adenine dinucleotide phosphate (NADPH) or maintain the cytosol-reduced (glucose-6-P- and isocitrate dehydrogenases, glutathione reductase), that decompose reactive oxygen species (catalase, superoxide dismutase, glutathione peroxidase), or detoxify glutathione-reactive electrophiles (soluble and microsomal glutathione transferases, glyoxalases II and I). The levels of reduced glutathione, malondialdehyde, and metallothionein and the glutathione redox status were also determined. Clams from Huelva sites with higher contaminant loads and metallothionein levels showed higher antioxidant and glutathione-related activities and a decreased glutathione level, lower malondialdehyde content, and a less oxidized glutathione status. This suggests that clams chronically exposed to contaminants released by Huelva and Guadalquivir Estuaries are better protected from oxidative stress than reference animals. Most biomarkers showed six-month cyclicity with up to threefold amplitudes, further supporting the inverse relationship between antioxidant defenses and oxidative damages. Thus the lower antioxidant defenses in June fit to maximum oxidative damages, whereas the high antioxidant defenses found in March and September through October agree with lower lipid damages and less oxidized glutathione status. The effect of environmental or endogenous factors on this cyclic response is discussed.

  8. BEHAVIORAL AND PHYSIOLOGICAL RESPONSES OF DAPHNIA MAGNA, CHLORELLA VULGARIS, CORBICULA FLUMINEA, LEPOMIS MACROCHIRUS, AND VIBRO FISCHERI

    Science.gov (United States)

    The research presented here is a continuation of work designed to further the science of available and developing continuous, automated water quality monitors and how they may be most effectively deployed in a watershed management plan and/or water quality early warning system (W...

  9. Puget Sound Dredged Disposal Analysis (PSDDA). Management Plan Report (MPR), Unconfined, Open-Water Disposal of Dredged Material. Phase 1 (Central Puget Sound)

    Science.gov (United States)

    1988-06-01

    laboratory experiments and field evaluations, clams and burrowing worms have been found to accumulate significant concentrations of organic compounds...the body tissue of sessile benthic organisms such as worms and clams that have been exposed in the laboratory to sediments taken from the field. Bio...creates special environmental conditions. Leachate . Water or other liquid that may have dissolved (leached) soluble materials, such as organic salts and

  10. Identification of an MITF gene and its polymorphisms associated with the Vibrio resistance trait in the clam Meretrix petechialis.

    Science.gov (United States)

    Zhang, Shujing; Yue, Xin; Jiang, Fengjuan; Wang, Hongxia; Liu, Baozhong

    2017-09-01

    Microphthalmia-associated transcription factor (MITF) regulates the transcription of its target genes by binding to their promoters. In this study, an MITF gene, MpMITF was identified in the clam Meretrix petechialis. The full-length cDNA of MpMITF is 3564 bp with an ORF of 1365 bp. The deduced amino acid sequence consists of a conserved functional structure of bHLH-LZ, which could bind with E-box. The mRNA and protein expression levels of MpMITF were significantly up-regulated 6 h post-Vibrio injection. The mRNA expression of MpMITF increased on day 2 and peaked on day 10 post-Vibrio immersion. Furthermore, MpMITF expression was significantly up-regulated in most resistant families of clams (P clams after the Vibrio immersion challenge. These results suggest that, in clams, MpMITF participates in the immune response against a Vibrio infection. Genotyping in two clam groups with different resistant levels to Vibrio parahaemolyticus (i.e., 11-R and 11-S), thirteen SNPs and five haplotypes were detected in the DNA sequence of MpMITF, of which five SNPs and two haplotypes were associated with Vibrio resistance. Four SNPs (SNP2, 5, 6 and 13) and one haplotype (Hap1) were further confirmed to be associated with Vibrio resistance in M. petechialis by association analysis in different clam families. This study deepens the understanding of MITF in marine bivalves and provides potential candidate markers for resistance selection in the clam M. petechialis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Hard clam walking: Active horizontal locomotion of adult Mercenaria mercenaria at the sediment surface and behavioral suppression after extensive sampling.

    Science.gov (United States)

    Tettelbach, Stephen T; Europe, James R; Tettelbach, Christian R H; Havelin, Jason; Rodgers, Brooke S; Furman, Bradley T; Velasquez, Marissa

    2017-01-01

    Locomotion of infaunal bivalve mollusks primarily consists of vertical movements related to burrowing; horizontal movements have only been reported for a few species. Here, we characterize hard clam walking: active horizontal locomotion of adults (up to 118 mm shell length, SL) of the commercially important species, Mercenaria mercenaria, at the sediment surface-a behavior only briefly noted in the literature. We opportunistically observed walking over a 10-yr period, at 9 different sites in the Peconic Bays, New York, USA, and tested several hypotheses for the underlying cause of this behavior through quantitative field sampling and reproductive analyses. Hard clam walking was exhibited by males and females at equal frequency, predominantly during June/July and October, when clams were in peak spawning condition. Extensive walking behavior appears to be cued by a minimum population density; we suggest it may be mediated by unidentified pheromone(s), infaunal pressure waves and/or other unidentified factors. There was no directionality exhibited by walking clams, but individuals in an area of extensive walking were highly aggregated and walking clams were significantly more likely to move toward a member of the opposite sex. Thus, we conclude that hard clam walking serves to aggregate mature individuals prior to spawning, thereby facilitating greater fertilization success. In the process of investigating this behavior, however, we apparently oversampled one population and reduced clam densities below the estimated minimum threshold density and, in so doing, suppressed extensive walking for a period of >3 years running. This not only reinforces the importance of detailed field investigations of species biology and ecology, even for those that are considered to be well studied, but also highlights the need for greater awareness of the potential for research activities to affect focal species behavior.

  12. RISK CHARACTERIZATION OF A COASTAL ENVIRONMENT FACING A MINING AND INDUSTRIAL AREA IN SARDINIA (SULCIS-IGLESIENTE BY MEANS OF CLUSTER SAMPLING AND CONTAMINANTS RESEARCH ON EDIBLE FISH AND CLAMS

    Directory of Open Access Journals (Sweden)

    P.L. Piras

    2011-01-01

    Full Text Available On the basis of the results obtained from the analysis carried out on various environmental substrates (sediments, sea water and bio-indicators, it can be assumed that there has been a transfer of contaminants from sediments to edible “biota” in the Boi Cerbus lagoon (Sulcis-Iglesiente. It has also been verified that the benthic clams, in particular the Cerastoderma glaucum, is the species mainly affected by heavy metals contamination, in particular Lead, even if the role of Cadmium in the lagoon would need further investigation.

  13. Differential protein expression in two bivalve species; Mytilus galloprovincialis and Corbicula fluminea; exposed to Cylindrospermopsis raciborskii cells.

    Science.gov (United States)

    Puerto, Maria; Campos, Alexandre; Prieto, Ana; Cameán, Ana; de Almeida, André Martinho; Coelho, Ana Varela; Vasconcelos, Vitor

    2011-01-17

    The cyanobacteria Cylindrospermopsis raciborskii is considered a threat to aquatic organisms due to the production of the toxin cylindrospermopsin (CYN). Despite the numerous reports evidencing the toxic effects of C. raciborskii cells and CYN in different species, not much is known regarding the toxicity mechanisms associated with this toxin and the cyanobacteria. In this work, a proteomics approach based in the two-dimensional gel electrophoresis and mass spectrometry was used to study the effects of the exposure of two bivalve species, Mytilus galloprovincialis and Corbicula fluminea, to CYN producing (CYN+) and non-producing (CYN-) C. raciborskii cells. Additionally the activities of glutathione S-transferase (GST) and glutathione peroxidase (GPx) were determined. Alterations in actin and tubulin isoforms were detected in gills of both bivalve species and digestive gland of M. galloprovincialis when exposed to CYN- and CYN+ cells. Moreover, GST and GPx activities changed in gills and digestive tract of bivalves exposed to both C. raciborskii freeze dried cells, in comparison to control animals exposed to the green alga Chlorella vulgaris. These results suggest the induction of physiological stress and tissue injury in bivalves by C. raciborskii. This condition is supported by the changes observed in GPx and GST activities which indicate alterations in the oxidative stress defense mechanisms. The results also evidence the capacity of CYN non-producing C. raciborskii to induce biochemical responses and therefore its toxicity potential to bivalves. The heat shock protein 60 (HSP60), extrapallial (EP) fluid protein and triosephosphate isomerase homologous proteins from gills of M. galloprovincialis were down-regulated specifically with the presence of CYN+ C. raciborskii cells. The presence of CYN may lead to additional toxic effects in M. galloprovincialis. This work demonstrates that proteomics is a powerful approach to characterize the biochemical effects of C

  14. Lead accumulation (adsorption and absorption) by the freshwater bivalve Corbicula fluminea in sediments contaminated by TiO2nanoparticles.

    Science.gov (United States)

    Fan, Xiulei; Wang, Peifang; Wang, Chao; Hu, Bin; Wang, Xun

    2017-12-01

    With the increasing production and applications of TiO 2 nanoparticles (NPs), their presence in aquatic environments, especially in sediments, will inevitably increase over time. Most studies investigating the influence of TiO 2 NPs on the bioaccumulation of co-existing contaminants have focused on the aqueous phase; however, few have examined the sediment phase, which contains more TiO 2 NPs and contaminants. We investigated the effects of TiO 2 NPs on Pb accumulation by Corbicula fluminea in sediments, and explored extracellular and intracellular Pb concentrations in the various soft tissues of the bivalve. Pb was spiked with 50 mg/kg in sediment and TiO 2 NPs/sediments ratios were within the range 0.2-3.0%. The results showed that TiO 2 NPs presented larger adsorption capacity and affinity to Pb ions than the sediments. In addition, the large adsorption capacity of TiO 2 NPs and the strong adsorption affinity to Pb ions caused part of the Pb ions released from sediments to aqueous phase were re-adsorbed by TiO 2 NPs in sediments. The concentration of TiO 2 NPs in C. fluminea tissues significantly increased with increasing TiO 2 NP content in sediments, following the order: gill > mantle > foot > visceral mass, which differed from the results found in the aqueous phase. In addition, the proportions of extracellular and intracellular Pb concentrations changed significantly in all the tissues as a result of TiO 2 NP contamination of sediments. TiO 2 NPs promote increased extracellular Pb in foot, mantle, and gill tissues, and increased intracellular Pb in the visceral mass. These results may be beneficial to more scientifically evaluate and predict the environmental risks of TiO 2 NPs to benthic organisms in sediments contaminated by heavy metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Transcriptome analysis of sex-related genes in the blood clam Tegillarca granosa.

    Science.gov (United States)

    Chen, Heng; Xiao, Guoqiang; Chai, Xueliang; Lin, Xingguan; Fang, Jun; Teng, Shuangshuang

    2017-01-01

    Blood clams (Tegillarca granosa) are one of the most commercial shellfish in China and South Asia with wide distribution in Indo-Pacific tropical to temperate estuaries. However, recent data indicate a decline in the germplasm of this species. Furthermore, the molecular mechanisms underpinning reproductive regulation remain unclear and information regarding genetic diversity is limited. Understanding the reproductive biology of shellfish is important in interpreting their embryology development, reproduction and population structure. Transcriptome sequencing (RNA-seq) rapidly obtains genetic sequence information from almost all transcripts of a particular tissue and currently represents the most prevalent and effective method for constructing genetic expression profiles. Non-reference RNA-seq, an Illumina HiSeq2500 Solexa system, and de novo assembly were used to construct a gonadal expression profile of the blood clam. A total of 63.75 Gb of clean data, with at least 89.46% of Quality30 (Q30), were generated which was then combined into 214,440 transcripts and 125,673 unigenes with a mean length of 1,122.63 and 781.30 base pairs (bp). In total, 27,325 genes were annotated by comparison with public databases. Of these, 2,140 and 2,070 differentially expressed genes (DEGs) were obtained (T05 T08 vs T01 T02 T04, T06 T07 vs T01 T02 T04; in which T01-T04 and T05-T08 represent biological replicates of individual female and male clams, respectively) and classified into two groups according to the evaluation of biological replicates. Then 35 DEGs and 5 sex-related unigenes, in other similar species, were investigated using qRT-PCR, the results of which were confirmed to data arising from RNA-seq. Among the DEGs, sex-related genes were identified, including forkhead box L2 (Foxl2), sex determining region Y-box (Sox), beta-catenin (β-catenin), chromobox homolog (CBX) and Sex-lethal (Sxl). In addition, 6,283 simple sequence repeats (SSRs) and 614,710 single nucleotide

  16. Low cycle fatigue properties of CLAM steel at 450 °C and 550 °C

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yanyun; Zhai, Xiangwei; Liu, Shaojun, E-mail: shaojun.liu@fds.org.cn

    2016-11-15

    Highlights: • Low cycle fatigue properties of CLAM steel were investigated at 450 °C and 550 °C. • CLAM steel showed the continuous softening up to fail failure under cyclic loading. The degree of softening increased with increasing temperature. • Dislocation density decrease and subgrain coarsening during the test process were the possible reasons for the cyclic softening of the CLAM steel. - Abstract: The low cycle fatigue behavior of China Low Activation Martensitic (CLAM) steel has been studied using a constant strain rate of 8 × 10{sup −3}/s with the strain amplitudes ranging from 0.3% to 0.8% at 450 °C and 550 °C. Cyclic stress response showed a gradual softening until complete failure. The fatigue life decreased with increasing test temperature, and the effect of temperature on fatigue life was more pronounced at lower strain amplitudes. The cyclic deformation behavior at different temperatures has been analyzed according to the hysteresis loop, and the mechanism of cyclic softening was interpreted in view of the changes taking place in dislocation density and lath structures. Evaluation of low cycle fatigue properties of CLAM steel at 450 °C and 550 °C can help in design of the Chinese Test Blanket Module (TBM) for the International Thermonuclear Experimental Reactor (ITER) and a future fusion power plant.

  17. Effect of post-weld heat treatment on the mechanical properties of CLAM/316L dissimilar joint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Junyu [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); University of Science and Technology of China, Hefei, Anhui 230027 (China); Huang, Bo [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Wu, Qingsheng, E-mail: qingsheng.wu@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Li, Chunjing; Huang, Qunying [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2015-11-15

    Highlights: • Dissimilar joints between CLAM and 316L steels welded by TIG were investigated. • After PWHTs, the hardening in HAZ on the CLAM steel side decreased remarkably. • Tempering at 740 °C for 2 h was considered as the preferable treatment rule. - Abstract: Dissimilar welding between China low activation martensitic (CLAM) steel and 316L austenitic stainless steel was investigated to achieve the reliable connection between test blanket modules (TBMs) and piping system in the international thermonuclear experimental reactor (ITER). The dissimilar joints were welded by tungsten inert gas (TIG) welding process with a filler material type-309. In order to stabilize the microstructure and improve the strength and toughness, post-weld heat treatments (PWHTs) of tempering at 740 °C, 780 °C and 820 °C, respectively, for 2 h were performed. The microstructure observation showed that tempering at 740 °C for 2 h was the preferable PWHT rule in this work. After the treatment, the hardening in heat affected zone (HAZ) on the CLAM steel side decreased remarkably. The tensile strength of the joint was roughly the same as that of the base metal. The impact toughness of HAZ on the CLAM steel side was 77% of that of the base metal. The absorbed energy of HAZ of 316L steel decreased by 93 J, and that of weld metal (WM) was 110 J after the treatment.

  18. Ca2+ is required for phosphorylation of clam p82/CPEB in vitro: implications for dual and independent roles of MAP and Cdc2 kinases.

    Science.gov (United States)

    Katsu, Y; Minshall, N; Nagahama, Y; Standart, N

    1999-05-01

    During early development gene expression is controlled principally at the translational level. Oocytes of the surf clam Spisula solidissima contain large stockpiles of maternal mRNAs which are translationally dormant or masked until meiotic maturation. Fertilisation of the oocyte leads to rapid polysomal recruitment of the abundant cyclin and ribonucleotide reductase mRNAs at about the time they undergo cytoplasmic polyadenylation. Clam p82, a 3' UTR RNA-binding protein, and a member of the CPEB (cytoplasmic polyadenylation element binding protein) family, functions as a translational masking factor in oocytes and as a polyadenylation factor in fertilised eggs. In meiotically maturing clam oocytes, p82/CPEB is rapidly phosphorylated on multiple residues to a 92-kDa apparent size, prior to its degradation during the first cell cleavage. Here we examine the protein kinase(s) that phosphorylates clam p82/CPEB using a clam oocyte activation cell-free system that responds to elevated pH, mirroring the pH rise that accompanies fertilisation. We show that p82/CPEB phosphorylation requires Ca2+ (model of clam p82/CPEB phosphorylation in which MAP kinase initially phosphorylates clam p82/CPEB, at a minor subset of sites that does not alter its migration, and cdc2 kinase is necessary for the second wave of phosphorylation that results in the large mobility size shift of clam p82/CPEB. The possible roles of phosphorylation for the function and regulation of p82/CPEB are discussed. Copyright 1999 Academic Press.

  19. NMR-based metabolomic investigations on the differential responses in adductor muscles from two pedigrees of Manila clam Ruditapes philippinarum to Cadmium and Zinc.

    Science.gov (United States)

    Wu, Huifeng; Liu, Xiaoli; Zhao, Jianmin; Yu, Junbao

    2011-01-01

    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.

  20. Ecophysiological and genetic traits of the Baltic clam Macoma balthica in the Baltic: Differences between populations in the Gdansk Bay due to acclimatization or genetic adaptation?

    NARCIS (Netherlands)

    Hummel, H.; Sokolowski, A.; Bogaards, R.H.; Wolowicz, M.

    2000-01-01

    Normal and irregular blunt clam-shells were found. Blunt shells increased with depth, because of increasing anoxia. Minimal weight-indices and reproductive stages were found at 40 m depth (near thermo-haline stratification) probably due to spawning just before sampling. Clams from shallower stations

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

    Science.gov (United States)

    Wu, Huifeng; Liu, Xiaoli; Zhao, Jianmin; Yu, Junbao

    2011-01-01

    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. PMID:22131959

  2. Selenium and stable isotopes of carbon and nitrogen in the benthic clam Corbula amurensis from Northern San Francisco Bay, California: May 1995-February 2010

    Science.gov (United States)

    Kleckner, Amy E.; Stewart, A. Robin; Luoma, Samuel N.

    2010-01-01

    The clam-based food webs of San Francisco Bay, California efficiently bioaccumlate selenium and thus provide pathways for exposure to predators important to the estuary. This study documents changes in monthly selenium concentrations for the clam Corbula amurensis, a keystone species of the estuary, at five locations in northern San Francisco Bay from 1995 through 2010. Samples were collected from designated U.S. Geological Survey stations and prepared and analyzed by U.S. Geological Survey methods. Stable isotopes of carbon and nitrogen in soft tissues of clams also were measured as an indicator of sources of selenium for the clams. These monitoring data indicate that clam selenium concentrations ranged from a low of 2 to a high of 22 micrograms per gram dry weight with strong spatial and seasonal variation over the period of study.

  3. 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.

  4. Metabolomic responses in caged clams, Ruditapes decussatus, exposed to agricultural and urban inputs in a Mediterranean coastal lagoon (Mar Menor, SE Spain).

    Science.gov (United States)

    Campillo, Juan A; Sevilla, Angel; Albentosa, Marina; Bernal, Cristina; Lozano, Ana B; Cánovas, Manuel; León, Víctor M

    2015-08-15

    The Mar Menor is a coastal lagoon affected by the growth of intensive agriculture and urban development in the surrounding area. Large amounts of chemical pollutants from these areas are discharged into El Albujón, a permanent water-course flowing into the lagoon. Biomarkers such as the activity of acetylcholinesterase or antioxidant enzymes have been previously tested in this lagoon demonstrating the presence of neurotoxicity and oxidative stress in clams transplanted in sites affected by the dispersion of the effluent from El Albujón. To complete this traditional toxicology work, a metabolomic profiling of these transplanted organisms has been carried out for the detection of metabolic biomarkers induced by agricultural/urban pollutants. More than 70 metabolites have been quantified using a targeting metabolomics platform based on HPLC-MS. The intracellular metabolic pattern was analyzed by PCA from the digestive gland of clams after 7 and 22 days of transplantation. Results showed a different profile of metabolite between organisms collected from control and exposed sites. At the shorter exposure time, there was an increase in several metabolites in the latter when compared with those from control sites, whereas metabolic profiling at 22 days showed that those metabolites were drastically diminished, with even lower levels than at control sites. These metabolites included: (i) 12 amino acids from the 21 proteogenic and HomoSer, (ii) osmotic protectants such as γ-butyrobetaine and taurine and (iii) nucleotides such as ITP. Regarding sulfur-containing molecules, taurine could be highlighted as a potential biomarker since its concentration was reduced by more than 30 times after 22 days of exposure, whereas the antioxidant glutathione remained constant in the organisms from both control and exposed sites. Although targeted metabolomics has been shown as an early technique of pollutant effect detection, the two-phase pattern could highlight a more complicated

  5. Organic matter modifies biochemical but not most behavioral responses of the clam Ruditapes philippinarum to nanosilver exposure.

    Science.gov (United States)

    Zhang, Tingwan; Pan, Jin-Fen; Hunt, Dana E; Chen, Min; Wang, Bo

    2018-02-01

    Adsorption of dissolved organic matter (DOM) can alter the environmental fate, bioavailability and toxicity of silver nanoparticles (Ag NPs). However, a number of questions remain about DOM's ability to modify nanotoxicity. Here, we examine the impact of humic acid (HA, as a model DOM) on the toxicity of Ag NPs (10 μg L-1) in the marine clam Ruditapes philippinarum. Results showed that DOM additions to Ag NP treatments reduce clam silver tissue burdens and the oxidative stress response. However, HA does not significantly affect the impact of Ag NPs on clam acetylcholinesterase activity and feeding behavior (measured as filtration rate). Overall, the integrated biological response index supports the conclusion that humic acid reduces the toxicity of Ag NPs, clearly indicating the importance of considering environmental factors when assessing potential risks posed by nanomaterials in natural settings. Copyright © 2017. Published by Elsevier Ltd.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yanyun [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Li, Chunjing, E-mail: chunjing.li@fds.org.cn [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Bo; Liu, Shaojun [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Qunying [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2014-12-15

    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.

  7. Frequency, Magnitude, and Possible Causes of Stranding and Mass-Mortality Events of the Beach Clam Tivela mactroides (Bivalvia: Veneridae.

    Directory of Open Access Journals (Sweden)

    Alexander Turra

    Full Text Available Stranding combined with mass-mortality events of sandy-beach organisms is a frequent but little-understood phenomenon, which is generally studied based on discrete episodes. The frequency, magnitude, and possible causes of stranding and mass-mortality events of the trigonal clam Tivela mactroides were assessed based on censuses of stranded individuals, every four days from September 2007 through December 2008, in Caraguatatuba Bay, southeastern Brazil. Stranded clams were classified as dying (closed valves did not open when forced or dead (closed valves were easily opened. Information on wave parameters and the living intertidal clam population was used to assess possible causes of stranding. This fine-scale monitoring showed that stranding occurred widely along the shore and year-round, with peaks interspersed with periods of low or no mortality. Dead clams showed higher mean density than dying individuals, but a lower mean shell length, attributed to a higher tolerance to desiccation of larger individuals. Wave height had a significant negative relationship to the density of dying individuals, presumed to be due to the accretive nature of low-energy waves: when digging out, clams would be more prone to be carried upward and unable to return; while larger waves, breaking farther from the beach and with a stronger backwash, would prevent stranding in the uppermost areas. This ecological finding highlights the need for refined temporal studies on mortality events, in order to understand them more clearly. Last, the similar size structure of stranded clams and the living population indicated that the stranded individuals are from the intertidal or shallow subtidal zone, and reinforces the ecological and behavioral components of this process, which have important ecological and socioeconomic implications for the management of this population.

  8. 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 (110mAg, 109Cd, 51Cr, 57Co, and 65Zn). 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.

  9. Norovirus recognizes histo-blood group antigens on gastrointestinal cells of clams, mussels, and oysters: a possible mechanism of bioaccumulation.

    Science.gov (United States)

    Tian, Peng; Engelbrektson, Anna L; Jiang, Xi; Zhong, Weiming; Mandrell, Robert E

    2007-09-01

    Outbreaks of norovirus (NoV) gastroenteritis are often associated with the consumption of contaminated bivalves such as oysters, clams, and mussels. Crassostrea virginica oysters trap the Norwalk virus through the intestinal type A-like histo-blood group antigen (HBGA), a possible mechanism of bioaccumulation responsible for NoV outbreaks. In this study, we tested binding and inhibition of binding in three species of oysters and one species each of clams and mussels with NoVs, representing four HBGA receptor-binding patterns. Our results indicated that all three oyster species expressed type A- and type O-like HBGA in their gastrointestinal tissue. Similar type A-like antigens also were found in mussels and clams, but only some of them express the O-like antigens. Both genogroups I and II recombinant norovirus-like particles (rNoVLPs) bound to gastrointestinal homogenates from oysters, mussels, and clams, and the binding was inhibited by preincubation of the rNoVLP with HBGA-specific monoclonal antibodies or with types A or O HBGA-positive human saliva. Co-localization of rNoVLPs and HBGA on gastrointestinal epithelial cells of oysters, mussels, and clams was also observed by immunofluorescent microscopy. Finally, the binding of rNoVLP to oyster gastrointestinal homogenates was inhibited by incubation with HBGA analogs. This study significantly expands our understanding that multiple HBGAs are expressed in oyster, mussel, and clam gastrointestinal tissues, which could be the major mechanism of bioaccumulation of NoVs by these bivalves. Our results also suggest that this bioaccumulation could be reversed by incubation with HBGA analogs, a possible important new strategy for depuration.

  10. 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

  11. Evaluation of Norfolk Harbor Deepening Project (A Study on Its Possible Impact on Oysters, Hard Clams and Oyster Drills).

    Science.gov (United States)

    1984-06-20

    Virginia 23062 DTIC 20 June 1984 ELECTE ~L&JMAR 12 i9BB IA B! ,", Contract No. DACW65-84-M-0056 -Ap’oved to: publicO t01b0 I D)WtbuZidon Unlimited .~Norfolk...impact on the transport of the larval oysters and hard clams during their planktonic stage. Oysters and hard clams are widely tolerant to high salinity...planktonic for about 2 weeks and during this period are transported by currents. This latter aspect will be covered later in our discussion on oysters. ~i

  12. Bioavailability of cadmium and biochemical responses on the freshwater bivalve Corbicula fluminea--the role of TiO₂ nanoparticles.

    Science.gov (United States)

    Vale, Gonçalo; Franco, Cristiana; Diniz, Mário S; dos Santos, Margarida M C; Domingos, Rute F

    2014-11-01

    The increasing and widespread applications of TiO2 engineered nanoparticles (nTiO2) led to the release of these materials into aquatic environments and consequently a change on the assessment of the environmental risk of trace metals. In this work, the role of two commercial nTiO2 with distinct crystalline phases and sizes (nTiO2-P25: 80% anatase+20% rutile, d=20nm; nTiO2-NA: 100% anatase, d=5 nm; 0.1 and 1.0 mg L(-1)) on Cd (112 μg L(-1)) speciation, biouptake and toxicity for the freshwater bivalve Corbicula fluminea was evaluated. The electroanalytical technique 'absence of gradients and Nernstian equilibrium stripping (AGNES)' was used to quantify the free Cd concentrations in the exposure medium in presence of both particles. Despite ca. 30-40% decrease of free Cd in the medium in presence of nTiO2, Cd uptake by C. fluminea was similar in the absence and presence of either of the particles. Superoxide dismutase and glutathione-S-transferase activities remained unchanged for Cd in absence and presence of nTiO2, whereas a significant increase of the catalase activity was obtained at the third day for Cd in presence of both nTiO2. Despite lipid peroxidation data shows that the presence of both nTiO2 seems to exert cells damage, a more quantitative description is not possible with the obtained data. The lack of clear-cut responses by the studied biomarkers, even when only in presence of Cd, do not allow insights into the effect of the presence of nTiO2 on the Cd toxicity to the bivalves. Notwithstanding, morphological changes in the digestive gland were clearly obtained in the presence of Cd, nTiO2 and Cd+nTiO2 indicating an inflammatory response. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Determination of multiple toxins in whelk and clam samples collected from the Chukchi and Bering seas.

    Science.gov (United States)

    Li, Aifeng; Chen, Huidan; Qiu, Jiangbing; Lin, Heshan; Gu, Haifeng

    2016-01-01

    Buccinidae whelk Neptunea varicifera (Dall), Cardiidae clam Serripes laperousii (Deshayes), and two unknown species of whelk and clam were collected from the Arctic Chukchi Sea and sub-Arctic Bering Sea in July 2014. In this study, the mollusk samples were analyzed by different liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) methods for multiple shellfish toxins, including okadaic acid (OA), pectenotoxin (PTX), yessotoxin (YTX), azaspiracid (AZA), cyclic imines (CI), and saxitoxin (STX) groups. PTX2 (≈2.0 μg kg(-1) whole tissues) was detected exclusively in the clam S. laperousii collected from the Chukchi Sea. OA and dinophysistoxin-1 (DTX1) were restricted to mollusk samples collected from the Bering Sea, and OA was the dominant component of the whelk N. varicifera (63 μg kg(-1) digestive gland) and an unknown species of whelk (6.8 μg kg(-1) digestive gland). Spirolide-1 (SPX1) was confirmed in most samples except for the whelk N. varicifera collected from the Bering Sea. The highest content of SPX1 (≈18.5 μg kg(-1) digestive gland) occurred in the whelk N. varicifera collected from the Chukchi Sea, along with the suspected presence of SPX-C, SPX-D and didesMe-SPX-C. YTX, as well as its derivatives 45-OH-YTX and 45,46,47-Trinor-YTX, were found in all samples, with the highest YTX content (66 μg kg(-1) digestive gland) present in the whelk N. varicifera collected from the Chukchi Sea. Interestingly, STX and dcSTX were measured only in the whelk N. varicifera and unknown species of clam collected from the Chukchi Sea. No AZA-group toxins, gymnodimine (GYM), or pinnatoxin G were found in any samples analyzed. Results demonstrated that the mollusk samples were contaminated by multiple shellfish toxins in the Chukchi and Bering seas. This study highlights the need to monitor potentially toxic microalgae in the Arctic and sub-Arctic regions, as well as species of mollusk that may be included in future commercial or

  14. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  15. Heavy metals in the clam Megapitaria squalida collected from wild and phosphorite mine-impacted sites in Baja California, Mexico: considerations for human health effects.

    Science.gov (United States)

    Méndez, Lia; Palacios, Elena; Acosta, Baudilio; Monsalvo-Spencer, Pablo; Alvarez-Castañeda, Ticul

    2006-06-01

    The "chocolate clam" Megapitaria squalida, is widely consumed by the population of several localities along the Pacific coast. Clams collected from seven stations in Bahía de la Paz, a bay within the Gulf of California, before and after the summer rainy season were analyzed for Pb, Ni, Cd, Mn, Zn, Cu, and Fe. The location of the sampling sites significantly affected the concentration of metals in clam tissues, but not in relation to the proximity to alleged contaminated sites. Clams from a site close to a phosphate mine had the highest levels of Pb, but only in April, and the highest concentrations of Cd were recorded in clams collected in areas with no anthropogenic activities. Clams from sites considered clean had higher levels of Cd, Fe, Zn, and Mn. The mean concentrations (microg/g dry weight) ranged from 0.1 to 7.8 for Pb, from 1.9 to 8.8 for Ni, from 1.5 to 11.1 for Cd, from 2.5 to 14.1 for Mn, from 47.2 to 64.6 for Zn, from 5.4 to 18.7 for Cu, and from 154 to 558 for Fe. Collecting clams in sites apparently pristine is no guarantee that metals will be in low concentrations.

  16. Premières observations sur la coexistence de Dreissena polymorpha, Corophium curvispinum et Corbicula spp. dans la rivière Moselle

    Directory of Open Access Journals (Sweden)

    BACHMANN V.

    1997-01-01

    Full Text Available La macrofaune benthique de la rivière Moselle a été échantillonnée par dragage sur plusieurs stations de son profil longitudinal, de juillet 1994 à septembre 1995. Ces dragages ont été réalisés suivant plusieurs transects, à des profondeurs de 1 à 4 mètres, sur chaque station. Ceux-ci ont permis de découvrir la présence de l'amphipode Corophium curvispinum et de deux formes (ou espèces ? différentes de bivalve du genre Corbicula. Ces recherches ont montré l'extension de l'aire de répartition de C. curvispinum à la Moselle française, jusqu'à Gondreville au moins (soit 137,5 km de cours nouvellement colonisé, et l'extension de l'aire de répartition du genre Corbicula jusqu'à Dieulouard (soit 337 km de cours depuis l'embouchure sur le Rhin. La distribution de ces espèces, réputées comme invasives et responsables de sérieux problèmes de "salissures" pour les utilisateurs d'eau brute des cours d'eau de plaine, semble être en relation avec la nature du substrat. Des phénomènes de compétition spatiale et trophique entre ces nouveaux arrivants et les populations macrobenthiques autochtones sont envisageables. Un suivi attentif de ces populations est nécessaire afin de prévenir d'éventuels problèmes économiques, voire écosystémiques.

  17. 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.

  18. Two molluscan BCL-2 family members from Manila clam, Ruditapes philippinarum: molecular characterization and immune responses.

    Science.gov (United States)

    Lee, Youngdeuk; Whang, Ilson; Lee, Sukkyoung; Menike, Udeni; Oh, Chulhong; Kang, Do-Hyung; Heo, Gang-Joon; Lee, Jehee; De Zoysa, Mahanama

    2013-06-01

    Apoptosis based immune responses are important component of host defense in mollusks. In this study, we have identified two novel molluscan BCL-2 cDNAs from Manila clam, Ruditapes philippinarum and named as RpBCL-2A and RpBCL-2B. There were four and three highly conserved BCL-2 homology (BH) regions in RpBCL-2A and RpBCL-2B, respectively suggesting these two genes could be different isoforms of anti-apoptotic BCL-2 family. Phylogenetic results revealed that Manila clam BCL-2 genes were clustered closely with invertebrate BCL-2 members. It gives evidence of their common origin and conserved features of invertebrate BCL-2 family. RpBCL-2A and 2B were expressed in tissue-specific manner showing the highest and lowest level of expression in gills and hemocytes, respectively. However there was no clear expression profile difference between two genes. After Vibrio tapetis challenge, transcriptional responses of RpBCL-2A and RpBCL-2B were induced in gills and hemocytes with high variation that could be due to effects of immune reactions of other host defense molecules. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Molecular cloning and characterization of SOCS-2 from Manila clam Ruditapes philippinarum.

    Science.gov (United States)

    Lee, Youngdeuk; Choi, Jin-Young; Oh, Chulhong; Kang, Do-Hyoung; Choi, Su-Young; Heo, Gang-Joon; Lee, Jehee; De Zoysa, Mahanama

    2014-02-01

    Suppressor of cytokine signaling (SOCS) family members are key regulators of immunological homeostasis. In this study, we have discovered the SOCS-2 member from Manila clam Ruditapes philippinarum and further analyzed its immune responses against lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid (poly I:C). Amino acid sequence of RpSOCS-2 consists of cytokine inducible SRC homology 2 (SH2) and SOCS box domains similar to vertebrate SOCS counterparts. It has the highest amino acid identity (41%) with Pacific oyster (Crassostrea gigas) SOCS-2 and showed close evolutional relationship with disk abalone (Haliotis discus discus) SOCS-2. Tissue specific expression results showed that RpSOCS-2 was constitutively expressed in all examined tissues with the highest level in gill tissue of un-challenged clams. RpSOCS-2 mRNA expression was up-regulated by LPS and poly I:C challenge in gills. Discovery of RpSOCS-2 homologue and expression analysis would support for understanding evolutional relationships and their role in innate immune responses in mollusks, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Inbreeding depression on growth and survival of full-sib family of Manila clam ( Ruditapes philippinarum)

    Science.gov (United States)

    Huo, Zhongming; Li, Na; Zhang, Xuekai; Li, Ying; Yan, Xiwu; Yang, Feng

    2017-02-01

    In present study, the inbreeding depression ( ID) of growth and survival of Manila clam (Ruditapes philippinarum) was investigated at larval and juvenile stages. Nine inbred families ( A 2, B 2, C 2, D 2, E 2, F 2, G 2, H 2 and I 2) were established by mating within nine full-sib families with expected inbreeding coefficient of 0.25. Inbred families showed significant differences in shell length and hatching rate of D-larvae (straight-hinged larvae). The larvae of the nine inbred families grew slower than those of control group ( CG), and their ID value ranged from 0.81% ± 6.09% to 16.10% ± 1.49%. The ID value of larval survival rate varied between 27.47% ± 9.36% and 70.50% ± 13.66%. The ID was also detected for juvenile growth in A 2, B 2, C 2, and D 2, which ranged from 4.60 ± 2.21 to 17.71 ± 7.73. The A 2 family maintained the highest juvenile survival rate, whereas the other inbred families exhibited ID values varying between 62.79% ± 4.54% and 96.14% ± 0.87%. The linear relationship of estimated ID between growth and survival was negatively correlated ( R = -0.434, P clam.

  1. 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.

  2. Tensile properties and fracturing behavior of weld joints in the CLAM at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Yucheng [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Xiao, Chengwen, E-mail: emoryxiao@163.com [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Wang, Xu; Yue, Jiajia; Zhu, Qiang [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2015-06-15

    Highlights: • We use the stress triaxiality theory to explain the plastic deformation and facture behavior of the joints during the short term tensile tests at high temperature. • The tensile strength of CLAM welded joint at high temperature is lower compared with that at room temperature. • We explained the formation of crack and the reason of fracture. - Abstract: The tensile properties and fracturing behavior of weld joints in the Chinese low activation martensitic steel (CLAM) at high temperatures were studied. The result revealed that the cracks of weld joints in the base metal would appear in the heat-affected zone, after post-weld heat treatment for the high-temperature tensile test. The microstructure in the fractured frontier had different deformation and directions, and the fractured surface had different angles, a result associating with the normal faulting and shear fracturing. The tri-axial theory of stress can well explain the deformation and fracturing behavior of weld joints in the high-temperature tensile.

  3. 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.

  4. Neuroprotection by freshwater clam extract against the neurotoxin MPTP in C57BL/6 mice.

    Science.gov (United States)

    Hsieh, Cho-Chen; Lin, Muh-Shi; Hua, Kuo-Feng; Chen, Wei-Jung; Lin, Chai-Ching

    2017-03-06

    Freshwater clams are a popular health food in Asia and are traditionally used to prevent hepatic inflammation. Freshwater clam extract (FCE) inhibits inflammatory responses in activated macrophages by reducing the activation of mitogen-activated protein kinase and nuclear factor kappa-light-chain-enhancer of activated B cells. In this study, we used a mouse model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine (MPTP; a neurotoxin)-induced Parkinson's disease (PD) to demonstrate the protective effect of FCE on dopamine neurons in the substantia nigra pars compacta (SNpc). Locomotor behavior and tyrosine hydroxylase immunohistochemical staining indicated that FCE significantly inhibited MPTP-induced dopaminergic cell loss in the SNpc. Glial fibrillary acidic protein immunohistochemistry and quantitative polymerase chain reaction analysis revealed that astroglial activation and tumor necrosis factor alpha, inducible nitric oxide synthase, and interleukin 1 beta production were significantly inhibited by FCE. The expressions of brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor, and nerve growth factor were markedly increased by FCE action against MPTP-induced toxicity. FCE showed a neuroprotective effect in a MPTP-induced PD model, which might be correlated with anti-inflammation and the stimulation of neurotrophic factors. Copyright © 2017. Published by Elsevier B.V.

  5. Trophic transfer of 134Cs in the Manila clam Ruditapes philippinarum.

    Science.gov (United States)

    Belivermiş, Murat; Kılıç, Önder; Sezer, Narin; Kalaycı, Gülşah; Metian, Marc

    2017-10-01

    Bioaccumulation of radiocaesium in many marine organisms occurs through complex trophic transfer mechanisms. The present study addresses the trophic transfer of 134Cs in the widely distributed marine bivalve, the Manila clam Ruditapes philippinarum, by experimentally determining the assimilation efficiency (AE) and the specific role of food quality or diet on the AE in this marine invertebrate. Pulse-chase feeding experiments were carried out on this clam using the phytoplankton species Tetraselmis chuii, Phaeodactylum tricornutum and Isochrysis galbana. Depuration kinetics of 134Cs over 21 days were analysed using a two-component exponential model. Observed assimilation efficiencies were consistently less than 10% but slightly varied among individuals fed on the three different phytoplankton species diets (T. chuii: AE = 8.4 ± 0.6%; P. tricornutum: AE = 9.8 ± 0.5%; I. galbana: AE = 5.3 ± 0.6%), although no statistical differences were observed. Comparing results from these experiments with existing data from the literature on the same species exposed to caesium through seawater, it appears that trophic transfer processes are the main accumulation pathway, contributing up to 96% of the global 134Cs bioaccumulation in this bivalve species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. 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.

  7. Vibrios in hatchery cultures of the razor clam, Solen marginatus (Pulteney).

    Science.gov (United States)

    Prado, S; Dubert, J; da Costa, F; Martínez-Patiño, D; Barja, J L

    2014-03-01

    Hatchery culture of the razor clam, Solen marginatus (Pulteney), has recently been developed in Galicia (NW Spain). However, recurrent episodes of mortalities of larval and post-larval cultures have been recorded during the course of various studies. The disease signs were similar to those described for other bivalve species in outbreaks caused by bacteria of the genus Vibrio. In this article, we present the results of microbiological monitoring of two batches of razor clams with different survival rates. All fermentative isolates were identified as members of the Splendidus clade within the genus Vibrio. Some of these isolates, identified as Vibrio splendidus-like, were clearly associated with the batch suffering mortalities, indicating their possible role as pathogens. Similar strains were found in the broodstock, suggesting vertical transmission of these bacteria. This is the first study of the microbiota associated with hatchery culture of S. marginatus, and the results will provide useful information for the optimization of a protocol for hatchery culture of this bivalve species. © 2013 John Wiley & Sons Ltd.

  8. Ocorrência do molusco asiático Corbicula fluminea (Müller, 1774 (Bivalvia, Corbiculidae no baixo rio Negro, Amazônia central Occurrence of the Asian mollusc Corbicula fluminea (Müller, 1774 (Bivalvia, Corbiculidae in the lower Rio Negro, Central Amazon Region, Brazil

    Directory of Open Access Journals (Sweden)

    Daniel Mansur Pimpão

    2008-01-01

    Full Text Available O rio Negro é um dos maiores afluentes do rio Amazonas, mas poucos moluscos foram registrados até o momento para aquele rio, representados apenas por gastrópodes. Foi registrada a presença do molusco bivalve exótico Corbicula fluminea na margem esquerda do baixo rio Negro, no lago do Tupé e no Catalão - margem direita do rio Negro, todas localidades no município de Manaus, Brasil. O registro foi realizado por meio da coleta de conchas e espécimes vivos. É o primeiro registro de C. fluminea para o estado do Amazonas e Amazônia central.The Rio Negro is one of the biggest Rio Amazonas tributaries. Few molluscs have been registered to that river yet, represented only by gastropods. It is reported the occurrence of the exotic bivalve mollusc Corbicula fluminea in left bank margin of Rio Negro, Lago do Tupé and Catalão - right bank margin of Rio Negro, all localities in the municipality of Manaus, Brazil. The species is recorded by a collection of shells and specimens alive. This is the first occurrence of C. fluminea in the Amazon State and Central Amazon.

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

    Science.gov (United States)

    1986-08-01

    comb winter, which allows the fall spawn to jelly Mnemiopsis leidyi are efficient establish in their absence, the feeders on the planktonic larvae of...Busycon canaliculatum, and the determining post-settling survival of lobed moon snail Polynices duplicatus softshell clams, predation by fish (Andrews 1970

  10. Caffeine impacts in the clam Ruditapes philippinarum: Alterations on energy reserves, metabolic activity and oxidative stress biomarkers.

    Science.gov (United States)

    Cruz, Diogo; Almeida, Ângela; Calisto, Vânia; Esteves, Valdemar I; Schneider, Rudolf J; Wrona, Frederick J; Soares, Amadeu M V M; Figueira, Etelvina; Freitas, Rosa

    2016-10-01

    Caffeine is known to be one of the most consumed psychoactive drugs. For this reason, caffeine is continuously released into the environment with potential impacts on inhabiting organisms. The current study evaluated the biochemical alterations induced in the clam species Ruditapes philippinarum after exposure for 28 days to caffeine (0.5, 3.0 and 18.0 μg/L). The results obtained showed that, with the increasing caffeine concentrations, an increase in clams defense mechanisms (such as antioxidant and biotransformation enzymes activity) was induced which was accompanied by an increase in protein content. Nevertheless, although an increase on defense mechanisms was observed, clams were not able to prevent cells from lipid peroxidation that increased with the increase of caffeine concentration. Furthermore, with the increase of exposure concentrations, clams increased their metabolic activity (measured by electron transport activity), reducing their energy reserves (glycogen content), to fight against oxidative stress. Overall, the present study demonstrated that caffeine may impact bivalves, even at environmentally relevant concentrations, inducing oxidative stress in organisms. The present study is an important contribution to address knowledge gaps regarding the impacts of long-term exposures to pharmaceuticals since most of the studies assessed the effects after acute exposures, most of them up to 96 h. Copyright © 2016. Published by Elsevier Ltd.

  11. Expression and localization of MCsialec, a sialic acid-specific lectin in the marine bivalve Manila clam, Ruditapes philppinarum.

    Science.gov (United States)

    Adhya, M; Choi, K-S; Yu, Y; Cho, M

    2010-11-01

    A novel sialic acid-specific lectin (MCsialec) was detected from an expressed sequenced tag (EST) sequence from Manila clam haemocytes infected with Perkinsus olseni. The cDNA of the lectin was cloned using gene-specific primers based on a previously determined EST and characterized. The full-length cDNA of MCsialec is 603 bp in length and encodes a polypeptide of 200 amino acids with a calculated molecular mass of 21.928 kDa. Sequence alignment and protein motif analyses showed that MCsialec shares identity with sialic acid-specific invertebrate lectins from Cepaea hortensis, Helix pomatia and Haliotis discus discus. The lectin was expressed in Escherichia coli M15 cells and purified using a Ni-NTA His-binding resin matrix for antibody production. The presence of the lectin in various tissues of Perkinsus-infected and uninfected Manila clams was analysed by both PCR and immunohistochemical localization assays. MCsialec was detected in each tissue of the clams; however, upon infection, the level of expression of the lectin increased in each tissue. Vibrio tapetis infection also induced high-level expression of MCsialec in the haemocytes. These data suggest that MCsialec plays a crucial role in the immune system of the Manila clam during pathogenic infection. © 2010 Blackwell Publishing Ltd.

  12. 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

  13. 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.

  14. PARTICLE REMOVAL RATES BY THE MUD SHRIMP UPOGEBIA PUGETTENSIS, ITS BURROW, AND A COMMENSAL CLAM: EFFECTS ON ESTUARINE PHYTOPLANKTON ABUNDANCE

    Science.gov (United States)

    The burrowing shrimp Upogebia pugettensis is an abundant intertidal inhabitant of Pacific Northwest bays and estuaries where it lives commensally with the bivalve Cryptomya californica. Suspension-feeding activities by the shrimp and by its commensal clam, as well as particle se...

  15. Metal sources to the Baltic clam Macoma balthica (Mollusca: Bivalvia) in the southern Baltic Sea (the Gulf of Gdansk)

    NARCIS (Netherlands)

    Sokolowski, A.; Wolowicz, M.; Hummel, H.

    2007-01-01

    Metal concentrations of Cu, Fe, Mn, Ni, Pb and Zn in an infaunal facultative deposit-feeding bivalve, the Baltic clam Macoma balthica, in the Gulf of Gdansk (southern Baltic Sea) were assessed and compared to selected concentrations of metals in the environment. Between October 1996 and September

  16. 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 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.

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

    Science.gov (United States)

    1985-02-01

    dredge with an escala - are absent above the mean tide line tor increases the catch of the more (Hibhert 1976). valuable small clams, but causes dis...Mann, D. Jablonski, V. Kennedy, S. Siddall, R. Goldberg , H. Landers, W.S. 1955. Summary of early Beattie, C. Falmagne, A. life history studies of the

  18. L’INVASION DU RÉSEAU HYDROGRAPHIQUE FRANÇAIS PAR LES MOLLUSQUES CORBICULA SPP. MODALITÉ DE COLONISATION ET RÔLE PRÉPONDÉRANT DES CANAUX DE NAVIGATION.

    Directory of Open Access Journals (Sweden)

    BRANCOTTE V.

    2002-04-01

    Full Text Available Originaire d’Asie et d’Afrique, Corbicula a colonisé la plupart des bassins hydrographiques européens depuis 1980. A la faveur de la découverte de nouvelles stations, les auteurs mettent en évidence l’importance du rôle des canaux de navigation dans la propagation du mollusque, par la mise en connexion des bassins versants et l’existence d’un milieu particulièrement favorable à la biologie de l’espèce. Corbicula a pénétré en France par au moins sept axes différents, parmi lesquels le Rhin joue un rôle prépondérant.

  19. 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

  20. Sampling trace organic compounds in water: a comparison of a continuous active sampler to continuous passive and discrete sampling methods

    Science.gov (United States)

    Coes, Alissa L.; Paretti, Nicholas V.; Foreman, William T.; Iverson, Jana L.; Alvarez, David A.

    2014-01-01

    A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring (CLAM) sampler (C.I.Agent® Storm-Water Solutions) is a submersible, low flow-rate sampler, that continuously draws water through solid-phase extraction media. CLAM samplers were deployed at two wastewater-dominated stream field sites in conjunction with the deployment of polar organic chemical integrative samplers (POCIS) and the collection of discrete (grab) water samples. All samples were analyzed for a suite of 69 TOCs. The CLAM and POCIS samples represent time-integrated samples that accumulate the TOCs present in the water over the deployment period (19–23 h for CLAM and 29 days for POCIS); the discrete samples represent only the TOCs present in the water at the time and place of sampling. Non-metric multi-dimensional scaling and cluster analysis were used to examine patterns in both TOC detections and relative concentrations between the three sampling methods. A greater number of TOCs were detected in the CLAM samples than in corresponding discrete and POCIS samples, but TOC concentrations in the CLAM samples were significantly lower than in the discrete and (or) POCIS samples. Thirteen TOCs of varying polarity were detected by all of the three methods. TOC detections and concentrations obtained by the three sampling methods, however, are dependent on multiple factors. This study found that stream discharge, constituent loading, and compound type all affected TOC concentrations detected by each method. In addition, TOC detections and concentrations were affected by the reporting limits, bias, recovery, and performance of each method.

  1. Occurrence of phytoplankton in the water and gut of the volta clam ...

    African Journals Online (AJOL)

    Members of the Bacillariophyta found at the surface and bottom layers belonged to six (6) genera (Asterionella, Diatoma, Fragilaria, Melosira, Navicula, and Synedra). Members of the Cyanophyta which were isolated from the gut only were Merismopedia elegans, Oscillatoria tenius and Planktothrix agardhii. Practical ...

  2. Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California; 2015

    Science.gov (United States)

    Cain, Daniel J.; Thompson, Janet K.; Crauder, Jeffrey; Parchaso, Francis; Stewart, Robin; Turner, Matthew A.; Hornberger, Michelle I.; Luoma, Samuel N.

    2016-07-22

    Trace-metal concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica), clam reproductive activity, and benthic macroinvertebrate community structure were investigated in a mudflat 1 kilometer south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in South San Francisco Bay, California. This report includes data collected by U.S. Geological Survey (USGS) scientists for the period from January 2015 to December 2015. These data are appended to long-term datasets extending back to 1974, and serve as the basis for the City of Palo Alto’s Near-Field Receiving Water Monitoring Program, initiated in 1994.

  3. Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California: 2014

    Science.gov (United States)

    Cain, Daniel J.; Thompson, Janet K.; Crauder, Jeff; Parcheso, Francis; Stewart, Robin; Kleckner, Amy E.; Dyke, Jessica; Hornberger, Michelle I.; Luoma, Samuel N.

    2015-01-01

    Trace-metal concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica), clam reproductive activity, and benthic macroinvertebrate community structure were investigated in a mudflat 1 kilometer (km) south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in South San Francisco Bay, Calif. This report includes the data collected by U.S. Geological Survey (USGS) scientists for the period January 2014 to December 2014. These append to long-term datasets extending back to 1974, and serve as the basis for the City of Palo Alto’s Near-Field Receiving Water Monitoring Program, initiated in 1994. 

  4. 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. coli<230MPN and Salmonella sp. absent in 25g of meat). However, the enteric viruses evaluated were detected throughout the analysis period, with the highest result for the hepatitis A virus (HAV); followed by Rotavirus-A (RVA); Human Adenovirus (HAdV) and Norovirus GI (NoV GI). The bioaccumulation of enteric viruses by A. brasiliana during a period of 24h was performed using NoV GI and GII, HAV, RVA and HAdV as models. Interestingly the mollusk demonstrated different uptake behaviors in relation to these viruses throughout the time period. NoV GI was the most adsorbed virus after 24h. HAV concentration was <1% at 3h, but it increased to <10% at 8h, remaining unchanged until 12h, and decreasing to <3% at 24h; HAdV reached its highest concentration at 12h, being released by the animals and lowering to <3% at 24h. RVA bioaccumulation was unstable over time, reaching its highest values after 24h (<5%); NoV GII bioaccumulation remained <1%. Thermal inactivation of HAdV-2 in A. brasiliana was also evaluated. After the usual gentle cooking procedure using different times (0, 1, 1.5, 3 and 5mins), viral infectivity was evaluated using ICC-et-RT-qPCR. The temperature inside the DT remained <80°C over time and after 5min of cooking the

  5. EVALUATION OF A FIRST-ORDER MODEL FOR THE PREDICTION OF THE BIOACCUMULATION OF PCBS AND DDT FROM SEDIMENT INTO THE MARINE DEPOSIT-FEEDING CLAM MACOMA NASUTA

    Science.gov (United States)

    A first-order model for predicting contaminant bioaccumulation from sediments into benthic invertebrates was validated using a marine deposit-feeding clam, Macoma nasuta, exposed to polychlorobiphenyl (PCB)-spiked and dichlorodiphenyltrichloroethane (DDT)-contaminated sediments. ...

  6. Incorporation of in situ exposure and biomarkers response in clams Ruditapes philippinarum for assessment of metal pollution in coastal areas from the Maluan Bay of China.

    Science.gov (United States)

    Wang, Zaosheng; Yan, Changzhou; Vulpe, Chris D; Yan, Yijun; Chi, Qiaoqiao

    2012-01-01

    The clams Ruditapes philippinarum were used to assess the impact of metal contaminants when transplanted to seven study sites along the Maluan Bay (China). Metal concentrations in digestive gland tissues of clams after 7-day in situ cage exposure were determined in conjunction with antioxidant enzyme activities. The results showed the importance of specific antioxidant biomarkers to assess complex pollutant mixtures and their good correlations to the pollutant compositions of deployment sites. Multivariate analysis indicated causal relationship between the chemicals at each study site and the biochemical "response" of the caged clams at these sites and demonstrated the potential presence of two different contaminant sources. This study suggested that the incorporation of tissue residue analysis with biomarkers response in caged clams together with factor analysis can be a useful biomonitoring tool for the identification of causal toxic pollutants and the assessment of complex metal pollutions in marine coastal environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Water Quality And Sediment Evaluation for Inner Harbor Navigation Canal Lock Replacement Project, New Orleans, Louisiana

    Science.gov (United States)

    2011-08-01

    Leptocheirus plumulosus 10-day solid phase toxicity tests. .............................................. 127 Table 44. Corbicula fluminea 28-day freshwater...solid phase bioaccumulation tests. ................... 131 Table 45. Corbicula fluminea 28-day freshwater solid phase bioaccumulation tests...132 Table 46. Corbicula fluminea 28-day freshwater solid phase bioaccumulation potential evaluation

  8. 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.

  9. 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.

  10. 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.

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