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Sample records for bivalve mollusc crassostrea

  1. Characterization of the mantle transcriptome in bivalves: Pecten maximus, Mytilus edulis and Crassostrea gigas.

    Science.gov (United States)

    Yarra, Tejaswi; Gharbi, Karim; Blaxter, Mark; Peck, Lloyd S; Clark, Melody S

    2016-06-01

    The calcareous shells secreted by bivalve molluscs display diverse and species specific structural compositions, which indicates possible divergent biomineralization processes. Thus, studying multiple mollusc species will provide a more comprehensive understanding of shell formation. Here, the transcriptomes of the mantle tissues responsible for shell deposition were characterized in three commercially relevant bivalve species. Using high-throughput sequencing and bioinformatics tools, de novo transcriptome assemblies of mantle tissues were generated for the mussel Mytilus edulis, the oyster Crassostrea gigas and the scallop Pecten maximus. These transcriptomes were annotated, and contigs with similarity to proteins known to have shell formation roles in other species were identified. Comparison of the shell formation specific proteins in the three bivalves indicates the possibility of species specific shell proteins. PMID:27160853

  2. Labelling and marketing of bivalve and gastropod molluscs retailed in Sardinia, Italy between 2009 and 2013

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    Domenico Meloni

    2015-06-01

    Full Text Available The aim of the present survey was to investigate the correct enforcement of the Community rules on the labelling and marketing of bivalve and gastropod molluscs retailed in Sardinia, Italy between 2009 and 2013. A total of 1500 packages and labels for live bivalve and gastropod molluscs were considered. A total of 375 labels (25% presented non-compliance concerning the wrong trade name and additional wrong or missing information. The highest percentage of anomalous labels has been detected in small-scale retail shops (35% and open-air markets (25% compared with the big retailing chains (20%. The 5% of packages were not in compliance with the European Community rules on packaging of bivalve and gastropod molluscs. The high percentage of non-compliance with the European regulations on labelling results is a strong limitation for the consumers and highlights the need to improve the control system about labelling of seafood products.

  3. The metal content of bivalve molluscs of a coastal lagoon of NW Mexico.

    Science.gov (United States)

    Frías-Espericueta, Martín G; Osuna-López, José I; Voltolina, Domenico; López-López, Gabriel; Izaguirre-Fierro, Gildardo; Muy-Rangel, María D

    2008-01-01

    The lagoonal system Altata-Ensenada del Pabellón supports important traditional fisheries and mollusc cultures and receives urban and agricultural effluents. The annual mean Cd contents of the oyster and mussel Crassostrea gigas and Mytella strigata of the inner mangrove swamps were higher than that of the clam Megapitaria squalida, which lives in areas under marine influence. Crassostrea corteziensis had the highest Cu and Zn contents, showing that it is a strong accumulator of both metals and especially of Zn, and there were no significant differences in the Pb content of the three species. PMID:18058043

  4. Relationships between innate immunity in bivalve molluscs and environmental pollution

    OpenAIRE

    MI Girón-Pérez

    2010-01-01

    The immune system of invertebrates, such as molluscs consists of innate mechanisms very effective against antigens commonly present in the environment. However, these defense strategies could be altered by pollutants. This review is focused mainly on the effect of metals, PCB, pesticides, PAHs, and others environmental pollutant on immune response of molluscs.

  5. Relationships between innate immunity in bivalve molluscs and environmental pollution

    Directory of Open Access Journals (Sweden)

    MI Girón-Pérez

    2010-06-01

    Full Text Available The immune system of invertebrates, such as molluscs consists of innate mechanisms very effective against antigens commonly present in the environment. However, these defense strategies could be altered by pollutants. This review is focused mainly on the effect of metals, PCB, pesticides, PAHs, and others environmental pollutant on immune response of molluscs.

  6. Genomic Analysis of the Pacific Oyster (Crassostrea gigas) Reveals Possible Conservation of Vertebrate Sex Determination in a Mollusc

    OpenAIRE

    Zhang, Na; Xu, Fei; Guo, Ximing

    2014-01-01

    Despite the prevalence of sex in animal kingdom, we have only limited understanding of how sex is determined and evolved in many taxa. The mollusc Pacific oyster Crassostrea gigas exhibits complex modes of sexual reproduction that consists of protandric dioecy, sex change, and occasional hermaphroditism. This complex system is controlled by both environmental and genetic factors through unknown molecular mechanisms. In this study, we investigated genes related to sex-determining pathways in C...

  7. Molluscs for Sale: Assessment of Freshwater Gastropods and Bivalves in the Ornamental Pet Trade.

    Science.gov (United States)

    Ng, Ting Hui; Tan, Siong Kiat; Wong, Wing Hing; Meier, Rudolf; Chan, Sow-Yan; Tan, Heok Hui; Yeo, Darren C J

    2016-01-01

    The ornamental pet trade is often considered a key culprit for conservation problems such as the introduction of invasive species (including infectious diseases) and overharvesting of rare species. Here, we present the first assessment of the biodiversity of freshwater molluscs in the ornamental pet trade in Singapore, one of the most important global hubs of the ornamental aquarium trade, and discuss associated conservation concerns. We recorded freshwater molluscs from ornamental pet shops and major exporters including non-ornamental species (e.g., hitchhikers, molluscs sold as fish feed). We recorded an unexpectedly high diversity-59 species-of freshwater bivalves and gastropods, with the majority (38 species or 64%) being from the Oriental region. In addition to morphological examination, we sequenced the DNA barcode region of mitochondrial CO1 and 16S genes to provide molecular data for the confirmation of the identification and for future re-identification. DNA barcodes were obtained for 50 species, and all but four were separated by > 3% uncorrected pairwise distances. The trade has been considered a main introduction pathway for non-native species to Singapore, and we found that out of 15 species in the trade as well as in the wild in Singapore, 12 are either introduced or of unknown origin, representing almost half of the known non-native freshwater molluscs in Singapore. Particularly prevalent are non-ornamental species: six hitchhikers on aquarium plants and six species sold as fish feed. We found that a quarter of the trade species have a history of introduction, which includes 11 known or potentially invasive species. We conclude that potential overharvesting is difficult to assess because only half of the trade species have been treated by IUCN. Of these, 21 species are of Least Concern and three are Data Deficient. Our checklist, with accompanying DNA barcodes, images, and museum vouchers, provides an important reference library for future monitoring

  8. Assessment of Heavy Metals in Bivalves Molluscs of Apulian Region: a 3-years control activity of a EU Laboratory

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    Miedico O.

    2013-04-01

    Full Text Available The bivalve molluscs represent an important matrix to be studied for several reasons. Their nutritional properties make them valuable to the consumers, so that their consumption and commercial value has risen worldwide. Simultaneously, their significant water-filtering capability and their persistence in the same place make them good bio-indicators of marine ecosystems. The presence of the heavy metal contaminants, as Cd, Pb and Hg, was investigated in bivalve molluscs such as mussels (Mytilus galloprovincialis, clams (Venus gallina and oysters (Ostrea edulis. In the present study, a survey was carried out on 334 samples addressed to the Istituto Zooprofilattico Sperimentale – Puglia e Basilicata, Foggia (ITALY between 2009-2011, and collected by official authorities along the coasts of Apulia Region. The conformity of heavy metal content in bivalve molluscs was verified, in according to EC Reg. 1881/2006. The compliance was found for the total amount of samples. The obtained data on heavy metals concentration in bivalve molluscs were compared with data found in monitoring studies on the incidence of heavy metals in 1981 in North-Western Mediterranean Sea, in 2003 in Tyrrhenian Sea and in 2010 in Pacific Ocean (Chile, reported in literature. The information obtained from this work offer an essential database, not only for the authorities involved in food control, but also for the official institutions responsible of a constant control of the marine ecosystem pollution.

  9. Review of the RNA Interference Pathway in Molluscs Including Some Possibilities for Use in Bivalves in Aquaculture

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    Leigh Owens

    2015-03-01

    Full Text Available Generalised reviews of RNA interference (RNAi in invertebrates, and for use in aquaculture, have taken for granted that RNAi pathways operate in molluscs, but inspection of such reviews show little specific evidence of such activity in molluscs. This review was to understand what specific research had been conducted on RNAi in molluscs, particularly with regard to aquaculture. There were questions of whether RNAi in molluscs functions similarly to the paradigm established for most eukaryotes or, alternatively, was it more similar to the ecdozoa and how RNAi may relate to disease control in aquaculture? RNAi in molluscs appears to have been only investigated in about 14 species, mostly as a gene silencing phenomenon. We can infer that microRNAs including let-7 are functional in molluscs. The genes/proteins involved in the actual RNAi pathways have only been rudimentarily investigated, so how homologous the genes and proteins are to other metazoa is unknown. Furthermore, how many different genes for each activity in the RNAi pathway are also unknown? The cephalopods have been greatly overlooked with only a single RNAi gene-silencing study found. The long dsRNA-linked interferon pathways seem to be present in molluscs, unlike some other invertebrates and could be used to reduce disease states in aquaculture. In particular, interferon regulatory factor genes have been found in molluscs of aquacultural importance such as Crassostrea, Mytilus, Pinctada and Haliotis. Two possible aquaculture scenarios are discussed, zoonotic norovirus and ostreid herpesvirus 1 to illustrate the possibilities. The entire field of RNAi in molluscs looks ripe for scientific exploitation and practical application.

  10. Haematopoiesis in molluscs: A review of haemocyte development and function in gastropods, cephalopods and bivalves.

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    Pila, E A; Sullivan, J T; Wu, X Z; Fang, J; Rudko, S P; Gordy, M A; Hanington, P C

    2016-05-01

    Haematopoiesis is a process that is responsible for generating sufficient numbers of blood cells in the circulation and in tissues. It is central to maintenance of homeostasis within an animal, and is critical for defense against infection. While haematopoiesis is common to all animals possessing a circulatory system, the specific mechanisms and ultimate products of haematopoietic events vary greatly. Our understanding of this process in non-vertebrate organisms is primarily derived from those species that serve as developmental and immunological models, with sparse investigations having been carried out in other organisms spanning the metazoa. As research into the regulation of immune and blood cell development advances, we have begun to gain insight into haematopoietic events in a wider array of animals, including the molluscs. What began in the early 1900's as observational studies on the morphological characteristics of circulating immune cells has now advanced to mechanistic investigations of the cytokines, growth factors, receptors, signalling pathways, and patterns of gene expression that regulate molluscan haemocyte development. Emerging is a picture of an incredible diversity of developmental processes and outcomes that parallels the biological diversity observed within the different classes of the phylum Mollusca. However, our understanding of haematopoiesis in molluscs stems primarily from the three most-studied classes, the Gastropoda, Cephalopoda and Bivalvia. While these represent perhaps the molluscs of greatest economic and medical importance, the fact that our information is limited to only 3 of the 9 extant classes in the phylum highlights the need for further investigation in this area. In this review, we summarize the existing literature that defines haematopoiesis and its products in gastropods, cephalopods and bivalves. PMID:26592965

  11. Prevalence and serotyping of Listeria monocytogenes in Portuguese live bivalve molluscs sampled in various steps along the sanitary control process

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    Pinto, Ana Luísa; Teixeira, Paula; Castilho, Fernanda; Felício, Maria Teresa; Pombal, Filomena

    2006-01-01

    The prevalence and contamination levels of Listeria monocytogenes were investigated in live bivalve molluscs for human consumption, collected in various steps of the commercial and sanitary circuits in the North of Portugal. Samples of di¡erent species were collected per lot before and after depuration treatment in two depuration units and further, when placed in retail markets. Listeria monocytogenes was isolated from 4% of the samples although with very low contam...

  12. Polonium-210 in marine mussels (bivalve molluscs) inhabiting the southern coast of India.

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    Khan, M Feroz; Wesley, S Godwin; Rajan, M P

    2014-12-01

    The present study focused on the determination of the alpha-emitter, (210)Po, in two species of marine mussels (bivalve molluscs) commonly available in the southern coastal region of India. The brown mussel, Perna indica was collected from the west coast and the green mussel, Perna viridis from the east coast. The concentration of (210)Po was related to the allometry (length of shell, wet/dry weight of shell/soft tissue) of the mussels and significant results were found. The study period focused on three seasons namely, pre-monsoon, monsoon and post-monsoon for a 1-year period (2010-2011). The results revealed higher activity levels in smaller-sized mussels compared to larger ones. Marked variation in (210)Po activity concentration was noted in the whole-body soft tissues between seasons and sampling site (p mussels was performed using the ERICA Assessment tool. The chronic exposure to mussels due to (210)Po was found to be lesser than the global benchmark dose rate of 10 μGy h(-1). The effective ingestion dose to adults who intake mussels was estimated to be in the range 5.1-34.9 μSv y(-1). The measurement contributes to the furthering of knowledge of (210)Po, since no data exist in this region. PMID:25042075

  13. Structure and Classification of Haemocytes in the Bivalve Mollusc Meretrix meretrix

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yanyan; REN Sulian; WANG Dexiu; SONG Weibo

    2006-01-01

    Light and electron microscopic studies were carried out in order to characterize haemocytes in the bivalve mollusc Meretrix meretrix. According to nucleus and cytoplasm characters, four types of haemocytes were recognized: agranular haemocytes, lymphoid haemocyte, large granular and small granular haemocytes. Agranular hamocyte is the main cell type,accounting for 75%. It is agranular with rich organelles in cytoplasm, including mitochondria, golgi body and endoplasmic reticulum. Glycogen deposits were usually found in this cell type. The number of lymphoid haemocyte accounts for 1% -2%. This cell type is agranular and shows a high ratio of nucleus to cytoplasm. A few organelles were found. High electrondense granules with diameters of 0.2 - 0.5 μm and rich organelles were found in small granular haemocyte. The proportion of this cell type is about 15%. Rich granules of high electron-dense with diameters of 0.8- 2.4μm were found in large granular haemocyte. The proportion of this cell type is about 10%, and the quantity of organelles is the least.

  14. Mixed function oxygenases and xenobiotic detoxication/toxication systems in bivalve molluscs

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    Moore, M. N.; Livingstone, D. R.; Donkin, P.; Bayne, B. L.; Widdows, J.; Lowe, D. M.

    1980-03-01

    Components of a xenobiotic detoxication/toxication system involving mixed function oxygenases are present in Mytilus edulis. Our paper critically reviews the recent literature on this topic which reported the apparent absence of such a system in bivalve molluscs and attempts to reconcile this viewpoint with our own findings on NADPH neotetrazolium reductase, glucose-6-phosphate dehydrogenase, aldrin epoxidation and other reports of the presence of mixed function oxygenases. New experimental data are presented which indicate that some elements of the detoxication/toxication system in M. edulis can be induced by aromatic hydrocarbons derived from crude oil. This includes a brief review of the results of long-term experiments in which mussels were exposed to low concentrations of the water accommodated fraction of North Sea crude oil (7.7-68 µg 1-1) in which general stress responses such as reduced physiological scope for growth, cytotoxic damage to lysosomal integrity and cellular damage are considered as characteristics of the general stress syndrome induced by the toxic action of the xenobiotics. In addition, induction in the blood cells of microsomal NADPH neotetrazolium reductase (associated with mixed function oxygenases) and the NADPH generating enzyme glucose-6-phosphate dehydrogenase are considered to be specific biological responses to the presence of aromatic hydrocarbons. The consequences of this detoxication/toxication system for Mytilus edulis are discussed in terms of the formation of toxic electrophilic intermediate metabolites which are highly reactive and can combine with DNA, RNA and proteins with subsequent damage to these cellular constituents. Implications for neoplasms associated with the blood cells are also discussed. Finally, in view of the increased use of mussel species in pollutant monitoring programmes, the induction phenomenon which is associated with microsomal enzymes in the blood cells is considered as a possible tool for the

  15. Polonium-210 in marine mussels (bivalve molluscs) inhabiting the southern coast of India

    International Nuclear Information System (INIS)

    The present study focused on the determination of the alpha-emitter, 210Po, in two species of marine mussels (bivalve molluscs) commonly available in the southern coastal region of India. The brown mussel, Perna indica was collected from the west coast and the green mussel, Perna viridis from the east coast. The concentration of 210Po was related to the allometry (length of shell, wet/dry weight of shell/soft tissue) of the mussels and significant results were found. The study period focused on three seasons namely, pre-monsoon, monsoon and post-monsoon for a 1-year period (2010–2011). The results revealed higher activity levels in smaller-sized mussels compared to larger ones. Marked variation in 210Po activity concentration was noted in the whole-body soft tissues between seasons and sampling site (p < 0.05). The dose rate assessment for mussels was performed using the ERICA Assessment tool. The chronic exposure to mussels due to 210Po was found to be lesser than the global benchmark dose rate of 10 μGy h−1. The effective ingestion dose to adults who intake mussels was estimated to be in the range 5.1–34.9 μSv y−1. The measurement contributes to the furthering of knowledge of 210Po, since no data exist in this region. - Highlights: • Polonium-210 was quantified in two species of Mytilid mussels inhabiting southern coast of India. • Polonium-210 activity showed significant variation among size classes, between seasons and sampling site. • The internal dose rate to mussels and the dose assessment to the adult population were performed

  16. Genomic analysis of the Pacific oyster (Crassostrea gigas) reveals possible conservation of vertebrate sex determination in a mollusc.

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    Zhang, Na; Xu, Fei; Guo, Ximing

    2014-11-01

    Despite the prevalence of sex in animal kingdom, we have only limited understanding of how sex is determined and evolved in many taxa. The mollusc Pacific oyster Crassostrea gigas exhibits complex modes of sexual reproduction that consists of protandric dioecy, sex change, and occasional hermaphroditism. This complex system is controlled by both environmental and genetic factors through unknown molecular mechanisms. In this study, we investigated genes related to sex-determining pathways in C. gigas through transcriptome sequencing and analysis of female and male gonads. Our analysis identified or confirmed novel homologs in the oyster of key sex-determining genes (SoxH or Sry-like and FoxL2) that were thought to be vertebrate-specific. Their expression profile in C. gigas is consistent with conserved roles in sex determination, under a proposed model where a novel testis-determining CgSoxH may serve as a primary regulator, directly or indirectly interacting with a testis-promoting CgDsx and an ovary-promoting CgFoxL2. Our findings plus previous results suggest that key vertebrate sex-determining genes such as Sry and FoxL2 may not be inventions of vertebrates. The presence of such genes in a mollusc with expression profiles consistent with expected roles in sex determination suggest that sex determination may be deeply conserved in animals, despite rapid evolution of the regulatory pathways that in C. gigas may involve both genetic and environmental factors. PMID:25213692

  17. Metals and pesticides in commercial bivalve mollusc production areas in the North and South Bays, Santa Catarina (Brazil).

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    de Souza, R V; Garbossa, L H P; Campos, C J A; Vianna, L F de N; Vanz, A; Rupp, G S

    2016-04-15

    Concentrations of heavy metals were quantified in mussels Perna perna and Pacific oysters Crassostrea gigas in 28 cultivation sites in the North and South Bays, SC (Brazil). Concentrations of pesticides were also quantified in these bivalve, water and sediment samples collected in 14 cultivation sites on four occasions in the period October 2012-October 2013. Pesticides were not detected in any of the mussel, oyster, water or sediment samples. The South Bay was found to be generally more contaminated with As while the North Bay showed higher concentrations of Ni. Concentrations of Pb and Cd were below the limit of detection of the method (0.5mg/kg) in all samples. Mussels accumulated more As and Ni than oysters, while the opposite was observed for Cu. Metal concentrations were below the maximum levels for foodstuffs specified in the Brazilian legislation. PMID:26897362

  18. Cytotoxic and antibacterial properties of Mytilus galloprovincialis, Ostrea edulis and Crassostrea gigas (bivalve molluscs) hemolymph

    OpenAIRE

    Hubert, Florence; Van Der Knaap, Wil; Noel, Thierry; Roch, Philippe

    1996-01-01

    Le plasma de la moule Mytilus galloprovincialis possède une activité cytotoxique dirigée à la fois contre des cellules de vertébrés (hématies et cellules tumorales de souris) et contre des protozoaires. Les cellules procaryotes (Escherichia coli et Vibrio alginolyticus) ne sont pas sensibles à l'activité cytotoxique. L'activité est toujours présente après dialyse des échantillons mais est inhibée par chauffage à 45°C. L'existence d'une importante variabilité individuelle, non corrélée à la co...

  19. Application of rapid test kits for the determination of Amnesic Shellfish Poisoning in bivalve molluscs from Great Britain.

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    Johnson, Sarah; Harrison, Keith; Turner, Andrew D

    2016-07-01

    Five commercial rapid screening methods for Amnesic Shellfish Poisoning were assessed for the analysis of naturally contaminated bivalve mollusc samples from GB. A range of shellfish species including mussels, scallops, clams, oysters and cockles, both positive and negative for domoic acid were assessed, with kit performance measured through comparison with the reference HPLC-UV method. Two lateral flow immunoassays manufactured by Neogen and Scotia Rapid Testing Ltd, were both found to provide a simple and accurate qualitative detection of ASP in shellfish. No false negative or false positive results were returned by either assay. The Scotia method showed the additional advantage of providing a numerical result which was found to correlate well with domoic acid concentration, thus providing a useful additional semi-quantitative aspect to the testing. Three ELISA kits, supplied by Beacon, Biosense and Bioo Scientific were all found to provide a good qualitative indication for the presence of domoic acid. Quantitative results varied between the three assays. The Beacon assay was the only kit to return no false negative results for samples containing domoic acid at concentrations above the maximum permitted regulatory limit of 20 mg/kg, but with, on average, a slight over-estimation of toxin concentrations. Both the Biosense and, more notably, the Bioo Scientific kits tended to under-estimate toxin levels, with both assays also returning false negative results. All methods were relatively straightforward to use, with the lateral flow assays in particular providing a simple and rapid methodology suited to those with no access to laboratory equipment. Whilst the data has provided some evidence for suitability for indicative testing for some species of bivalve shellfish from GB, further work would ideally be required using a larger number of test kit batches on a greater number of samples for any method being utilised safely for routine testing. PMID:27070387

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

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    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.

  1. Identification of growth increments in the shell of the bivalve mollusc Arctica islandica using backscattered electron imaging.

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    Karney, G B; Butler, P G; Scourse, J D; Richardson, C A; Lau, K H; Czernuszka, J T; Grovenor, C R M

    2011-01-01

    Annually resolved growth increments in the shell of the bivalve mollusc Arctica islandica have previously been used in combination with geochemical measurements to successfully construct high-resolution proxy records of past marine environmental conditions. However, to ensure the accuracy of these paleoenvironmental reconstructions it is essential that the annual growth series of increments within the examined shells are reliably identified, and can be distinguished from spurious lines caused by nonannual perturbations such as those resulting from storm disturbance. The current methods used for identifying the growth increment series are sometimes compromised because of ambiguity that results from the employed preparation methods. Here it is shown that backscattered electron imaging of polished shell cross sections may be used to clearly discriminate between the two compositionally and structurally distinct increments that comprise 1 year of outer shell growth. This method, involving minimal specimen preparation, is likely to be primarily useful as a validation technique of particular value in cases where increment identification using existing methods is difficult or ambiguous. PMID:21118202

  2. Morphology and ecology of bivalve molluscs from Admiralty Bay, King George Island, Antarctica

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    Theresinha M. Absher

    1998-08-01

    Full Text Available Bivalve species were collected from shallow coastal areas of King George Island (Martel, Mackellar and Ezcurra Inlets of Admiralty Bay. Twenty one species belonging to 16 genera and 12 families were identified and their morphometric and morphological shell characteristics were described. Three main characteristics were found to be common to the majority of the bivalve species sampled: 1 thin fragile shells; 2 small size of individuals (76%, and 3 the lack of true cardinal teeth (72%. Comparison of calcium data from a tropical estuary and a subantarctic coastal shallow area suggested that the calcium in the sea water was not a constraint to shell building but shell thickness could be an adaptation to the efficiency of energy partitioning. Small individual size and the lack of true cardinal teeth are discussed in relation to a high deposition environment and widespread mud bottoms.Espécies de bivalves foram coletadas na região costeira rasa da Ilha Rei George (Enseadas Martel, Mackellar e Ezcurra da Baía do Almirantado. Vinte e uma espécies pertencentes a 16 gêneros e 12 famílias foram identificadas e as caractrísticas morfológicas e morfométricas das conchas descritas. Destacaram-se 3 características principais comuns à maioria das espécies: 1 conchas finas e frágeis; 2 pequeno tamanho dos indivíduos (76%, e 3 a ausência de dentes cardinais (72%. A comparação entre os dados de cálcio de um estuário tropical e uma região rasa costeira subantártica sugeriu que os valores de cálcio na água do mar não seriam uma restrição à formação das conchas, mas a espessura das conchas poderia ser uma adaptação à eficiência na distribuição da energia. Discute-se a ausência de dentes cardinais e pequeno tamanho dos indivíduos em ralação a um ambiente de alta deposição e abundância de fundos lodosos.

  3. Assessment of bioavailability of weathered oil residues using caged bivalves (Crassostrea gigas and Mytilus edulis) as indicator organisms

    International Nuclear Information System (INIS)

    In April 1988, an estimated 400,000 gallons of San Joaquin Valley crude oil spilled into Peyton Slough and subsequently into Suisun Bay from an oil refinery in Martinez, California. The crude oil initially impacted a number of ecologically sensitive environments including estuarine water, marsh grasses, marsh and shoreline sediment, and intertidal sediment. A four-year oil weathering study was performed to determine the concentrations of environmentally important compounds in the stranded oil, to monitor changes in these concentrations over time, and to assess the potential long-term impact of the spilled oil in these various environments. As a result of marked differences in the rate of weathering at the different sites, a bioaccumulation component was added to the original study design in order to assess the bioavailability of crude oil residues remaining four-years post spill. Caged bivalves (Crassostrea gigas and Mytilus edulis) were deployed at the three study sites as sentinel organisms and exposed for three months. Sediments and organism tissues were analyzed using gas chromatography/mass spectrometry for polynuclear aromatic hydrocarbon (PAH) assemblages characteristics of the spilled oil. Advanced hydrocarbon fingerprinting techniques (e.g., double ratio plots of characteristic alkyl PAHs) were used to match distributions in the organisms and in the study site sediments

  4. Interactive effects of copper exposure and environmental hypercapnia on immune functions of marine bivalves Crassostrea virginica and Mercenaria mercenaria.

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    Ivanina, Anna V; Hawkins, Chelsea; Sokolova, Inna M

    2016-02-01

    Estuarine organisms such as bivalves are commonly exposed to trace metals such as copper (Cu) and hypercapnia (elevated CO2 levels) in their habitats, which may affect their physiology and immune function. This study investigated the combined effects of elevated CO2 levels (∼800-2000 μatm PCO2, such as predicted by the near-future scenarios of global climate change) and Cu (50 μg l(-1)) on immune functions of the sediment dwelling hard clams Mercenaria mercenaria and an epifaunal bivalve, the eastern oyster Crassostrea virginica. Clams and oysters were exposed for 4 weeks to different CO2 and Cu levels, and tissue Cu burdens and immune parameters were assessed to test the hypothesis that hypercapnia will enhance Cu uptake due to the higher bioavailability of free Cu(2+) and increase the immunomodulatory effects of Cu. Exposure to Cu stimulated key immune parameters of clams and oysters leading to increased number of circulating hemocytes, higher phagocytosis and adhesion ability of hemocytes, as well as enhanced antiparasitic and antibacterial properties of the hemolymph reflected in higher activities of lysozyme and inhibitors of cysteine proteases. Lysozyme activation by Cu exposure was most prominent in normocapnia (∼400 μatm PCO2) and an increase in the levels of the protease inhibitors was strongest in hypercapnia (∼800-2000 μatm PCO2), but other immunostimulatory effects of Cu were evident in all PCO2 exposures. Metabolic activity of hemocytes of clams and oysters (measured as routine and mitochondrial oxygen consumption rates) was suppressed by Cu exposure likely reflecting lower rates of ATP synthesis and/or turnover. However, this metabolic suppression had no negative effects of the studied immune functions of hemocytes such as phagocytosis or adhesion capacity. Hypercapnia (∼800-2000 μatm PCO2) slightly but significantly enhanced accumulation of Cu in hemocytes, consistent with higher Cu(2+) bioavailability in CO2-acidified water, but

  5. Species composition, richness, and distribution of marine bivalve molluscs in Bahía de Mazatlán, México

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    Esqueda-González, María del Carmen; Ríos-Jara, Eduardo; Galván-Villa, Cristian Moises; Rodríguez-Zaragoza, Fabian Alejandro

    2014-01-01

    Abstract We describe the composition and distribution of bivalve molluscs from the sandy and rocky intertidal and the shallow subtidal environments of Bahía de Mazatlán, México. The bivalve fauna of the bay is represented by 89 living species in 28 families, including 37 new records and four range extensions: Lithophaga hastasia, Adula soleniformis, Mactrellona subalata, and Strigilla ervilia. The number of species increases from the upper (44) and lower intertidal (53) to the shallow subtidal (76), but only 11 (17%) have a wide distribution in the bay (i.e., found in all sampling sites and environments). The bivalve assemblages are composed of four main life forms: 27 epifaunal species, 26 infaunal, 16 semi-infaunal, and 20 endolithic. A taxonomic distinctness analysis identified the sampling sites and environments that contribute the most to the taxonomic diversity (species to suborder categories) of the bay. The present work increased significantly (31%) to 132 species previous inventories of bivalves of Bahía de Mazatlán. These species represent 34% of the bivalve diversity of the southern Golfo de California and approximately 15% of the Eastern Tropical Pacific region. PMID:24843252

  6. Protandric hermaphroditism in the whale-fall bivalve mollusc Idas washingtonia

    Science.gov (United States)

    Tyler, Paul A.; Marsh, Leigh; Baco-Taylor, Amy; Smith, Craig R.

    2009-09-01

    Whale falls provide abundant but relatively ephemeral, sulphide-rich habitat islands on the deep-sea floor. To explore life-history adaptations to whale-fall habitats, we examined the reproductive biology of Idas washingtonia, a bathymodiolin mussel occurring in abundance on sunken whale skeletons in the deep northeast Pacific Ocean. Analysis of the reproductive biology of I. washingtonia demonstrates strong evidence of protandric hermaphroditism. Developing males were recognised in individuals as small as 1.7 mm shell length and spermatogenesis continued until ˜7 mm length. At >6.5 mm, males were generally spent and the first previtellogenic oocytes were observed. Although developing females were found as small as 4.5 mm shell length, most well-developed females were >6 mm shell length. Overall, females only formed ˜12% of the population. As with other modiolid bivalves, fecundity was high and the egg size whale falls even though these may have been severely reduced in abundance since the peak of commercial whaling activity in the 20th century.

  7. SURVEY ON V. CHOLERAE, V. VULNIFICUS AND V. PARAHAEMOLYTICUS IN BIVALVE MOLLUSCS OF THE ADRIATIC SEA AND PROPOSAL OF AN ANALYTICAL PROTOCOL

    Directory of Open Access Journals (Sweden)

    M.L. Valeri

    2009-06-01

    Full Text Available Bivalve molluscs from Adriatic sea were analyzed for V. parahaemolyticus, V. cholerae e V. vulnificus presence. The isolates on TCBS Agar and m-CPC Agar were selected on the basis of a new biochemical screening, that showed a good performance, because among 2344 strains from primary culture only 237 (10% were presumptively assigned to the species of interest. The PCR analyses was performed for the target genes toxR hlyA, ctxA, tcpI (V. cholerae, toxR, tl, tdh, trh (V. parahaemolyticus, vvhA and viuB (V. vulnificus. Among the 9 strains confirmed to belong to V. parahaemolyticus specie, 6 were sucrose positive. On 215 samples of molluscs only 5 resulted positive for V. parahaemolyticus being toxR+, tl+, although non pathogenic (tdh-, trh-, and none for V. cholerae e V. vulnificus.

  8. Interactive effects of pH and metals on mitochondrial functions of intertidal bivalves Crassostrea virginica and Mercenaria mercenaria

    International Nuclear Information System (INIS)

    Highlights: •Interactive effects of trace metals Cd and Cu and pH were studied in mitochondria of clams and oysters. •Mitochondrial respiration and membrane potential of bivalves were robust to pH variation (6.6–7.8). •Elevated levels of Cd and Cu inhibited mitochondrial respiration in the pH-dependent manner but did not affect the membrane potential. •Negative effects of Cd and Cd on mitochondrial respiration were alleviated at low pH (7.0 and below). •Moderate acidosis may protect molluscan mitochondria from metal toxicity. -- Abstract: Intertidal bivalves experience broad fluctuations of environmental temperature, pH and oxygen content which could change their intracellular pH. They are also exposed to trace metals such as cadmium (Cd) and copper (Cu) that accumulate in their tissues and may negatively affect mitochondrial functions and bioenergetics. We determined the interactive effects of pH and trace metals (25 μM Cd or Cu) on mitochondrial functions (including respiration and membrane potentials in both ADP-stimulated (state 3) and resting (state 4) states) of two common marine bivalves, the hard clams (Mercenaria mercenaria) and eastern oysters (Crassostrea virginica). In the absence of the trace metals, mitochondrial functions of C. virginica and M. mercenaria were insensitive to pH in a broad physiologically relevant range (6.6–7.8). Mitochondrial respiration was generally suppressed by 25 μM Cd or Cu (with the stronger effects observed for ADP-stimulated compared to the resting respiration) while the mitochondrial membrane potential was unaffected. pH modulated the effects of Cu and Cd on mitochondrial respiration of the bivalves. In oysters, Cu suppressed ADP-stimulated mitochondrial respiration at high and low pH values (6.6 and 7.8, respectively), but had no effect in the intermediate pH range (7.0–7.4). In clams, the negative effect of Cu on ADP-stimulated respiration was only observed at extremely high pH (7.8). A decrease in p

  9. Interactive effects of pH and metals on mitochondrial functions of intertidal bivalves Crassostrea virginica and Mercenaria mercenaria

    Energy Technology Data Exchange (ETDEWEB)

    Ivanina, Anna V.; Sokolova, Inna M., E-mail: isokolov@uncc.edu

    2013-11-15

    Highlights: •Interactive effects of trace metals Cd and Cu and pH were studied in mitochondria of clams and oysters. •Mitochondrial respiration and membrane potential of bivalves were robust to pH variation (6.6–7.8). •Elevated levels of Cd and Cu inhibited mitochondrial respiration in the pH-dependent manner but did not affect the membrane potential. •Negative effects of Cd and Cd on mitochondrial respiration were alleviated at low pH (7.0 and below). •Moderate acidosis may protect molluscan mitochondria from metal toxicity. -- Abstract: Intertidal bivalves experience broad fluctuations of environmental temperature, pH and oxygen content which could change their intracellular pH. They are also exposed to trace metals such as cadmium (Cd) and copper (Cu) that accumulate in their tissues and may negatively affect mitochondrial functions and bioenergetics. We determined the interactive effects of pH and trace metals (25 μM Cd or Cu) on mitochondrial functions (including respiration and membrane potentials in both ADP-stimulated (state 3) and resting (state 4) states) of two common marine bivalves, the hard clams (Mercenaria mercenaria) and eastern oysters (Crassostrea virginica). In the absence of the trace metals, mitochondrial functions of C. virginica and M. mercenaria were insensitive to pH in a broad physiologically relevant range (6.6–7.8). Mitochondrial respiration was generally suppressed by 25 μM Cd or Cu (with the stronger effects observed for ADP-stimulated compared to the resting respiration) while the mitochondrial membrane potential was unaffected. pH modulated the effects of Cu and Cd on mitochondrial respiration of the bivalves. In oysters, Cu suppressed ADP-stimulated mitochondrial respiration at high and low pH values (6.6 and 7.8, respectively), but had no effect in the intermediate pH range (7.0–7.4). In clams, the negative effect of Cu on ADP-stimulated respiration was only observed at extremely high pH (7.8). A decrease in p

  10. New insights from the oyster Crassostrea rhizophorae on bivalve circulating hemocytes.

    Directory of Open Access Journals (Sweden)

    Mauro de Freitas Rebelo

    Full Text Available Hemocytes are the first line of defense of the immune system in invertebrates, but despite their important role and enormous potential for the study of gene-environment relationships, research has been impeded by a lack of consensus on their classification. Here we used flow cytometry combined with histological procedures, histochemical reactions and transmission electron microscopy to characterize the hemocytes from the oyster Crassostrea rhizophorae. Transmission electron microscopy revealed remarkable morphological characteristics, such as the presence of membranous cisternae in all mature cells, regardless of size and granulation. Some granular cells contained many cytoplasmic granules that communicated with each other through a network of channels, a feature never previously described for hemocytes. The positive reactions for esterase and acid phosphatase also indicated the presence of mature cells of all sizes and granule contents. Flow cytometry revealed a clear separation in complexity between agranular and granular populations, which could not be differentiated by size, with cells ranging from 2.5 to 25 µm. Based on this evidence we suggest that, at least in C. rhizophorae, the different subpopulations of hemocytes may in reality be different stages of one type of cell, which accumulates granules and loses complexity (with no reduction in size as it degranulates in the event of an environmental challenge.

  11. The effects of cadmium of the growth and metallothionein expression of the bivalve larvae, crassostrea virginica

    Energy Technology Data Exchange (ETDEWEB)

    Craig, K.D. [Univ. of Charleston, WV (United States); Burnett, K.; Ringwood, A.; MacDougal, K.; Kendall, L.

    1994-12-31

    Oyster larvae, Crassostrea virginica, were exposed to 20 ppb of cadmium (Cd) and fed (mixture of Isochrysis galbana & Chaetoceros gracilis, 40mL) in the laboratory for 10 days. On the 0, 4, 7 and 10 day the larvae samples were taken and frozen. Then they were homogenized, centrifuged, ultrafiltered through a membrane separation technique used to segregate substances according to the molecular weight and size. The cytosolic protein was first partially purified by gel permeation, then by PAGE (Polyacrylamide Gel Electrophoresis). The controls and metal exposed larvae were evaluated on total wet weight and the metallothioneins (MT) were identified from the preparations using silver staining techniques. No significant changes could be detected in the controls. However, there was a great number dead at the beginning of the experiment. Cd accumulation began at the time of exposure. This suggests that surface area may play a role in determining short-term accumulation rates. Cd effects on growth (wet weight) was slightly different, the exposed weighed less than or equal to the controls. In addition, the Cd uptake via food played an insignificant role compared to direct uptake from sea water. Between day 0 and 7 there was a number of mortalities for the controls and exposed. In addition, there was a major weight change with the exposed, they appeared to weigh less than the controls on day 7, whereas on day 4 they weighed more. So weight is a very sensitive indicator of toxic stress.

  12. Fast and selective pressurized liquid extraction with simultaneous in cell clean up for the analysis of alkylphenols and bisphenol A in bivalve molluscs.

    Science.gov (United States)

    Salgueiro-González, N; Turnes-Carou, I; Muniategui-Lorenzoa, S; López-Mahía, P; Prada-Rodríguez, D

    2012-12-28

    A novel and green analytical methodology for the determination of alkylphenols (4-tert-octylphenol, 4-n-octylphenol, 4-n-nonylphenol, nonylphenol technical mixture) and bisphenol A in bivalve mollusc samples was developed and validated. The method was based on selective pressurized liquid extraction (SPLE) with a simultaneous in cell clean up combined with liquid chromatography–electrospray ionization tandem mass spectrometry in negative mode (LC–ESI-MS/MS). Quantitation was performed by standard addition curves in order to correct matrix effects. The analytical features of the method were satisfactory: relative recoveries varied between 80 and 107% and repeatability and intermediate precision were measurement was estimated on the basis of an in-house validation according to EURACHEM/CITAC guide. Quantitation limits of the method (MQL) ranged between 0.34 (4-n-octylphenol) and 3.6 ng g(−1) dry weight (nonylphenol). The main advantages of the method are sensitivity, selectivity, automaticity, low volumes of solvents required and low sample analysis time (according with the principles of Green Chemistry). The method was applied to the analysis of mussel samples of Galicia coast (NW of Spain). Nonylphenol and 4-tert-octylphenol were measured in all samples at concentrations between 9.3 and 372 ng g(−1) dw. As an approach, the human daily intake of these compounds was estimated and no risk for human health was found. PMID:23218190

  13. Effect of marine contamination on the genetic population structure of the bivalve Crassostrea angulata; Efecto de la contaminacion marina sobre la estructura genetica poblacional del bivalvo Crassostrea angulata

    Energy Technology Data Exchange (ETDEWEB)

    Cross, Ismael; Rebordinos, Laureana [Laboratorio de Genetica, Facultad de Ciencias del Mar, Universidad de Cadiz, Cadiz (Spain)

    2003-06-15

    Seven enzyme loci were analyzed in three natural populations of Crassostrea angulata located on the southern Atlantic coast of the Iberian Peninsula. Two of the populations showed distinct levels of contamination by heavy metals, whereas the third was not contaminated and served as control. These seven loci were shown to be very variable in terms of the number of alleles, polymorphism and average heterozygosity. The Lap and Mdh1 loci presented null alleles. A significant positive correlation was found between the number of alleles and the concentration of iron that was fitted to a model of linear regression. However, this correlation was negative for the heterozygosity, and significant for cadmium and zinc. The Em, Lap, Mdh1 y Xdh loci showed a deficit of heterozygotes in all the populations. The values of heterozygotic deficit (D) were statistically significant between the contaminated populations and the control for Mdh1 and very close to a significant level for Em. In Pgm, a heterozygotic excess appeared in the control population and deficit, which was correlated to the increased levels of metal concentration, occurred in the other two populations. The differences between the D values of the three populations were also significant in this locus. Positive, negative and significant relationships were obtained between the concentration of metals and some alleles of the Em, Lap and Pgm loci. Also, the homozygotic genotypes of the alleles with positive correlation values were selected in the contaminated areas, while the heterozygotes were more favoured in the control population, showing an adaptive behavior and corroborating the utility of some of these loci as biomarkers in studies of population dynamics in areas subjected to environmental contamination. [Spanish] Se analizaron siete loci alozimicos en tres poblaciones naturales de Crassostrea angulata localizadas en la costa suratlantica de la Peninsula Iberica. Dos de las poblaciones mostraban distintos niveles

  14. Geochemical survey and metal bioaccumulation of three bivalve species (Crassostrea gigas, Cerastoderma edule and Ruditapes philippinarum) in the Nord Medoc salt marshes (Gironde estuary, France)

    International Nuclear Information System (INIS)

    A 15-month experiment combining a geochemical survey of Cd, Cu, Zn and Hg with a bioaccumulation study for three filter-feeding bivalve species (oysters, Crassostrea gigas; cockles, Cerastoderma edule; and clams, Ruditapes philippinarum) was conducted in a breeding basin of the Nord Medoc salt marshes connected to the Gironde estuary, which is affected by historic polymetallic pollution. Regular manual surface measurements of temperature, salinity, pH and dissolved O2 concentration and hourly multiprobe in situ measurements throughout several periods for 6-8 weeks were performed. The geochemical behavior of metals in water, suspended particulate matter and sediment and their ecotoxicological impact on the three bivalve species were evaluated by in situ exposure of juvenile oysters (water column) and adult cockles and clams (sediment surface). The physico-chemical parameters reflected seasonal variations and basin management. A distinct daily periodicity (except salinity) indicated intense photosynthesis and respiration. In summer, low dissolved O2 saturations (∼40-50%) occurred in the early morning at 30 cm above the sediment, whereas in depressions, the water column near the sediment surface was suboxic. Cadmium, Zn and Cu concentrations in suspended particulate matter exceeded typical estuarine values and were much higher than the homogeneously distributed concentrations in different depth ranges of the basin sediment. Particles collected in sediment traps showed intermediate metal concentrations close to sediment values. These results suggest trace metal recycling due to reductive dissolution under suboxic conditions at the sediment surface resulting in trace metal release to the water column and adsorption onto suspended particles. Dissolved Cd, Zn and Hg concentrations (e.g. 13-136 ng l-1; 0.3-25.1 μg l-1 and 0.5-2.0 ng l-1, respectively) in the basin corresponded to the concentration range typically observed in the Gironde estuary, except for some maximum

  15. Interactive effects of CO2 and trace metals on the proteasome activity and cellular stress response of marine bivalves Crassostrea virginica and Mercenaria mercenaria

    International Nuclear Information System (INIS)

    Highlights: • Elevated PCO2 enhanced accumulation of Cu and Cd in the gills of mollusks. • The proteasome activities were affected by metals but robust to elevated PCO2. • Exposure to Cd and Cu had opposite effects on the proteasome activity. • Combined exposure to Cu and elevated PCO2 negatively affected energy status. - Abstract: Increased anthropogenic emission of CO2 changes the carbonate chemistry and decreases the pH of the ocean. This can affect the speciation and the bioavailability of metals in polluted habitats such as estuaries. However, the effects of acidification on metal accumulation and stress response in estuarine organisms including bivalves are poorly understood. We studied the interactive effects of CO2 and two common metal pollutants, copper (Cu) and cadmium (Cd), on metal accumulation, intracellular ATP/ubiquitin-dependent protein degradation, stress response and energy metabolism in two common estuarine bivalves—Crassostrea virginica (eastern oyster) and Mercenaria mercenaria (hard shell clam). Bivalves were exposed for 4–5 weeks to clean seawater (control) and to either 50 μg L−1 Cu or 50 μg L−1 Cd at one of three partial pressures of CO2 (PCO2 ∼395, ∼800 and ∼1500 μatm) representative of the present-day conditions and projections of the Intergovernmental Panel for Climate Change (IPCC) for the years 2100 and 2250, respectively. Clams accumulated lower metal burdens than oysters, and elevated PCO2 enhanced the Cd and Cu accumulation in mantle tissues in both species. Higher Cd and Cu burdens were associated with elevated mRNA expression of metal binding proteins metallothionein and ferritin. In the absence of added metals, proteasome activities of clams and oysters were robust to elevated PCO2, but PCO2 modulated the proteasome response to metals. Cd exposure stimulated the chymotrypsin-like activity of the oyster proteasome at all CO2 levels. In contrast, trypsin- and caspase-like activities of the oyster proteasome

  16. Interactive effects of CO₂ and trace metals on the proteasome activity and cellular stress response of marine bivalves Crassostrea virginica and Mercenaria mercenaria

    Energy Technology Data Exchange (ETDEWEB)

    Götze, Sandra [Alfred Wegener Institute, Helmholtz Centre for Polar, Marine Research, Functional Ecology, 27570 Bremerhaven (Germany); Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223 (United States); Matoo, Omera B. [Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223 (United States); Beniash, Elia [Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA (United States); Saborowski, Reinhard [Alfred Wegener Institute, Helmholtz Centre for Polar, Marine Research, Functional Ecology, 27570 Bremerhaven (Germany); Sokolova, Inna M., E-mail: isokolov@uncc.edu [Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223 (United States)

    2014-04-01

    Highlights: • Elevated PCO₂ enhanced accumulation of Cu and Cd in the gills of mollusks. • The proteasome activities were affected by metals but robust to elevated PCO₂. • Exposure to Cd and Cu had opposite effects on the proteasome activity. • Combined exposure to Cu and elevated PCO₂ negatively affected energy status. - Abstract: Increased anthropogenic emission of CO₂ changes the carbonate chemistry and decreases the pH of the ocean. This can affect the speciation and the bioavailability of metals in polluted habitats such as estuaries. However, the effects of acidification on metal accumulation and stress response in estuarine organisms including bivalves are poorly understood. We studied the interactive effects of CO₂ and two common metal pollutants, copper (Cu) and cadmium (Cd), on metal accumulation, intracellular ATP/ubiquitin-dependent protein degradation, stress response and energy metabolism in two common estuarine bivalves—Crassostrea virginica (eastern oyster) and Mercenaria mercenaria (hard shell clam). Bivalves were exposed for 4–5 weeks to clean seawater (control) and to either 50 μg L⁻¹ Cu or 50 μg L⁻¹ Cd at one of three partial pressures of CO₂ PCO₂ ~395, ~800 and ~1500 μatm) representative of the present-day conditions and projections of the Intergovernmental Panel for Climate Change (IPCC) for the years 2100 and 2250, respectively. Clams accumulated lower metal burdens than oysters, and elevated PCO₂ enhanced the Cd and Cu accumulation in mantle tissues in both species. Higher Cd and Cu burdens were associated with elevated mRNA expression of metal binding proteins metallothionein and ferritin. In the absence of added metals, proteasome activities of clams and oysters were robust to elevated PCO₂, but PCO₂ modulated the proteasome response to metals. Cd exposure stimulated the chymotrypsin-like activity of the oyster proteasome

  17. Can bivalve veligers escape feeding currents of adult bivalves?

    NARCIS (Netherlands)

    Troost, K.; Veldhuizen, R.; Stamhuis, E.J.; Wolff, W.J.

    2008-01-01

    While the stock of introduced Pacific oysters (Crassostrea gigas) increased in the Oosterschelde estuary (SW Netherlands), so did the filtration pressure of all bivalve species together. In the same period, stocks of native bivalves declined slightly. The expansion of Pacific oysters in Dutch estuar

  18. Coexistence of Pacific oyster Crassostrea gigas (Thunberg, 1793) and blue mussels Mytilus edulis Linnaeus, 1758 on a sheltered intertidal bivalve bed?

    DEFF Research Database (Denmark)

    Holm, M.W.; Davids, J.K.; Dolmer, Per;

    2016-01-01

    and M. edulis were collected from the bivalve bed, shell lengths were converted into biomass, which were interpolated to create biomass contours and combined with modelled topography of the bivalve bed to study niche separation. The bivalve bed slowly extended northwards over a period of 11 years, where......, and as C. gigas have been present in the ecosystem for more than 40 years, we hypothesize that the presence of C. gigas has altered the spatial and temporal distribution of M. edulis by inducing a niche separation. The spatiotemporal development of the bivalve bed was determined using orthophotos. C. gigas...

  19. The use of algal substitutes and the requirement for live algae in the hatchery and nursery rearing of bivalve molluscs: an international survey

    OpenAIRE

    Coutteau, P.; Sorgeloos, P.

    1992-01-01

    The mass-production of micro-algae has been recognized by several authors as the main bottle-neck for the culture of bivalve seed. This has prompted a search for alternatives to on-site algal production, such as dried heterotrophically-grown algae, preserved algal pastes, micro-encapsulated diets, and yeasts. However the extent to which these products have been tried, and rejected or retained by hatchery operators is poorly documented. Also, the actual algal requirement and production cost of...

  20. Mollusc gonadotropin-releasing hormone directly regulates gonadal functions: a primitive endocrine system controlling reproduction.

    Science.gov (United States)

    Treen, Nicholas; Itoh, Naoki; Miura, Hanae; Kikuchi, Ippei; Ueda, Takenori; Takahashi, Keisuke G; Ubuka, Takayoshi; Yamamoto, Kazutoshi; Sharp, Peter J; Tsutsui, Kazuyoshi; Osada, Makoto

    2012-04-01

    Gonadotropin-releasing hormone (GnRH) is central to the control of vertebrate reproductive cycles and since GnRH orthologs are also present in invertebrates, it is likely that the common ancestor of bilateral animals possessed a GnRH-like peptide. In order to understand the evolutionary and comparative biology of GnRH peptides we cloned the cDNA transcripts of prepro GnRH-like peptides from two species of bivalve molluscs, the Yesso scallop Patinopecten yessoensis and the Pacific oyster Crassostrea gigas. We compared their deduced uncleaved and mature amino acid sequences with those from other invertebrates and vertebrates, and determined their sites of expression and biological activity. The two molluscan GnRH sequences increased the number of known protostome GnRHs to six different forms, indicating the current classification of protostome GnRHs requires further revision. In both molluscs, RT-PCR analysis showed that the genes were highly expressed in nervous tissue with lower levels present in peripheral tissues including the gonads, while immunocytochemistry, using anti-octopus GnRH-like peptide, demonstrated the presence of GnRH-like peptide in neural tissue. Putative scallop GnRH-like peptide stimulated spermatogonial cell division in cultured scallop testis, but the scallop GnRH-like peptide did not stimulate LH release from cultured quail pituitary cells. This is the first report of the cloning of bivalve GnRH-like peptide genes and of molluscan GnRH-like peptides that are biologically active in molluscs, but not in a vertebrate. PMID:22326349

  1. Antiviral immunity in marine molluscs.

    Science.gov (United States)

    Green, Timothy J; Raftos, David; Speck, Peter; Montagnani, Caroline

    2015-09-01

    Marine molluscs, like all living organisms, are constantly exposed to viruses and have evolved efficient antiviral defences. We review here recent developments in molluscan antiviral immunity against viruses belonging to the order Herpesvirales. Emerging results suggest an interferon-like response and autophagy are involved in the antiviral defence of bivalves to viral infection. Multi-functional plasma proteins from gastropods and bivalves have been identified to have broad-spectrum antiviral activity against mammalian viruses. The antiviral defences present in molluscs can be enhanced by genetic selection, as shown by the presence of oyster strains specifically resistant to ostreid herpesvirus type 1. Whether varying amounts or different isoforms of these antiviral plasma proteins contributes to genetic resistance is worthy of further research. Other evolutionarily conserved antiviral mechanisms, such as RNA interference and apoptosis, still need further characterization. PMID:26297577

  2. Management for mollusc culture in Mexico

    OpenAIRE

    Marcet, G; Jimenez, F.; Rangel, C.; Arriaga, R

    1992-01-01

    Mollusc culture began formerly in Mexico in 1800, with the pearl oyster Pinctada mazatlanica. Oyster culture began in a commercial basis in the sixties, as an activity developed by the Mexican government in the Gulf of Mexico, yet the exploitation of the species was until 1989 reserved to fishermen grouped in cooperatives. Production data shows a noticeable variability up to 1986; from then, yearly production averaged 50,000 tonnes of Crassostrea virginica from the Gulf of Mexico. The whole y...

  3. Lead and other heavy metals (cadmium and mercury accumulation in bivalve mollusks (Mytilus galloprovincialis, Ruditapes spp. and Crassostrea gigas sampled in Sardinia in 2008-2012

    Directory of Open Access Journals (Sweden)

    Pierluigi Piras

    2013-12-01

    Full Text Available The Sardinian shellfish farming, like the national, is mainly focused on mussels and carpet-shell clams, still less on cupped oyster farming. After Olbia’s Gulf, various lagoon areas along the coastal perimeter have been interested to shellfish farming. They are transitional waters, whose state of pollution must be evaluated both as ecosystem’s health and as directly/indirectly human risk. This also applies to heavy metals such as lead, cadmium and mercury, arising both from anthropogenic that geological-natural activity. The aim of the present study is to investigate the variability of the concentrations of these metals in different mollusks to make a comparative assessment, detect trends (over the five-years or cyclicrecurring and identify hot spots. In 2008- 2012, 984 samples have been analysed by inductively coupled plasma mass spectrometry technique. Of them, 599 in pre-marketing (for classification of production areas or their monitoring and the remaining during marketing. The difference between the average levels of the three metals in the different mollusks species was statistically significant, with Pb>Cd>Hg, and there was evidence of a gradual downward trend, albeit moderate, in the contamination levels, with a significant seasonality in concentrations levels, of lead in particular. Also comparisons between the bio-monitored coastal areas were statistically different. Since the samples were representative of the entire production of bivalve mollusks in Sardinia and the contamination allowable limits have never been exceeded in the products marketed, it can be concluded that these products are safe, pointing out that maintenance of monitoring/surveillance plans provides useful information species-dependent, site-specific and temporal trends.

  4. Influence of toxic cyanobacteria on community structure and microcystin accumulation of freshwater molluscs

    International Nuclear Information System (INIS)

    Community structure and microcystin accumulation of freshwater molluscs were studied before and after cyanobacterial proliferations, in order to assess the impact of toxic blooms on molluscs and the risk of microcystin transfer in food web. Observed decrease in mollusc abundance and changes in species richness in highly contaminated waters were not significant; however, relative abundances of taxa (prosobranchs, pulmonates, bivalves) were significantly different before and after cyanobacterial bloom. Pulmonates constituted the dominant taxon, and bivalves never occurred after bloom. Microcystin accumulation was significantly higher in molluscs from highly (versus lowly) contaminated waters, in adults (versus juveniles) and in pulmonates (versus prosobranchs and bivalves). Results are discussed according to the ecology of molluscs, their sensitivity and their ability to detoxify. - Proliferations of toxic cyanobacteria may alter the structure of mollusc communities with cyanotoxin accumulation depending on age and taxon

  5. Histone H3 gene in the Pacific oyster, Crassostrea gigas Thunberg, 1793: molecular and cytogenetic characterisations

    Directory of Open Access Journals (Sweden)

    Karine Bouilly

    2010-12-01

    Full Text Available The Pacific oyster, Crassostrea gigas Thunberg, 1793 (2n = 20 is an economically important mollusc species cultured throughout the world. The most frequently used technique for molecular cytogenetic studies is fluorescence in situ hybridisation which offers new opportunities for the identification of oyster chromosomes. In oysters, it has been used to locate telomeric sequences, satellite DNA, simple sequence repeats, ribosomal RNA genes, and bacteriophage P1 clones. However, regarding chromosome identification, no study has been done with histone H3 gene. Histone H3 is among the most conserved eukaryotic proteins. Most histone H3 genes are repeatedly organised into clusters, which make them an ideal chromosomal marker. In bivalves, some data exist concerning sequence information but little knowledge is available concerning the physical mapping of histone genes. The histone H3 gene was sequenced in C. gigas and phylogenetic analysis revealed that C. gigas was more closely related to Ostrea edulis Linnaeus, 1758 and species of the genus Mytilus Linnaeus, 1758. In C. gigas, the histone H3 gene was mapped on two different pairs of chromosomes, one at an interstitial site on the long arm of chromosome pair 4, and the other on the telomeres of the smaller chromosome pair (pair 10. Polymorphism was detected on the telomeres of pair 10, once it was possible to observe single or double signals. Comparative chromosomal mapping should improve our understanding of bivalve genome organisation.

  6. Histological techniques for marine bivalve molluscs: update

    OpenAIRE

    Kim, Y.; Ashton-Alcox, K.A.; Powell, E.N.

    2006-01-01

    This chapter describes the procedures for determining the reproductive stage of oysters, mytilid mussels, and dreissenid mussels collected for NOAA’s National Status and Trends Mussel Watch Project. Analyses are conducted on paraffin-embedded tissues sectioned at a 5-μm thickness and stained using a pentachrome staining procedure. Each slide is examined microscopically to determine the animal’s sex and stage of gonadal development. A semi-quantitative ranking is assigned.

  7. Saxitoxin analysis in bivalve molluscs. Seafoodplus Traceability

    OpenAIRE

    Etienne, Monique

    2006-01-01

    Paralytic shellfish poisoning (PSP) is caused by consumption of a wide variety of shellfish which accumulated saxitoxins (STXs) from marine dinoflagellates (Alexandrium minutum, A. tamarense, Gymnodinium catenatum, Pyrodinium bahamense) and affect a wide variety of shellfish. There are about 20 saxitoxin analogs with closely related structures. A regulatory level of 0.8 mg/kg shellfish meat as STX equivalents has existed in North America and Europe for many years. The methods of determination...

  8. Effect of mangroves on distribution, diversity and abundance of molluscs in mangrove ecosystem: a review

    OpenAIRE

    Milad Kabir; Marziye Abolfathi; Abdolmajid Hajimoradloo; Saeed Zahedi; Kandasamy Kathiresan; Sheyda Goli

    2014-01-01

    The present study aims to identify relationship between the structural and ecological characteristics of mangrove ecosystem and mollusc communities. Bivalve and gastropod are considered as the main molluscs of mangrove forests and often show marked zonation patterns both horizontally and vertically. Gastropods have high distribution in the mangrove forests probably due to their mobile characteristic, while bivalves are often confined to a narrow seaward zone, due to feeding, larva...

  9. Developing tools for the study of molluscan immunity: The sequencing of the genome of the eastern oyster, Crassostrea virginica.

    Science.gov (United States)

    Gómez-Chiarri, Marta; Warren, Wesley C; Guo, Ximing; Proestou, Dina

    2015-09-01

    The eastern oyster, Crassostrea virginica, provides important ecological and economical services, making it the target of restoration projects and supporting a significant fishery/aquaculture industry with landings valued at more than $100 million in 2012 in the United States of America. Due to the impact of infectious diseases on wild, restored, and cultured populations, the eastern oyster has been the focus of studies on host-pathogen interactions and immunity, as well as the target of selective breeding efforts for disease resistant oyster lines. Despite these efforts, relatively little is known about the genetic basis of resistance to diseases or environmental stress, not only in eastern oyster, but also in other molluscan species of commercial interest worldwide. In order to develop tools and resources to assist in the elucidation of the genomic basis of traits of commercial, biological, and ecological interest in oysters, a team of genome and bioinformatics experts, in collaboration with the oyster research community, is sequencing, assembling, and annotating the first reference genome for the eastern oyster and producing an exhaustive transcriptome from a variety of oyster developmental stages and tissues in response to a diverse set of environmentally-relevant stimuli. These transcriptomes and reference genome for the eastern oyster, added to the already available genome and transcriptomes for the Pacific oyster (Crassostrea gigas) and other bivalve species, will be an essential resource for the discovery of candidate genes and markers associated with traits of commercial, biological, and ecologic importance in bivalve molluscs, including those related to host-pathogen interactions and immunity. PMID:25982405

  10. Overwiew on selective breeding and genetic improvement in bivalve shellfish

    OpenAIRE

    Boudry, Pierre

    2004-01-01

    Dr. Boudry focussed his talk on oysters, which are the most important bivalve species produced world wide (more than 4 million tons). One of the main characteristic of bivalve aquaculture is that most of the juveniles ("seed or "spat") are collected from natural recruitment (e.g. 100% of the European mussel production). Hatchery propagation is used in the case of introduced species (e.g. Crassostrea gigas in USA) or limited natural recruitment. The most significant genetic improvement ...

  11. Effect of orgnotin compounds (TBT) used in antifouling paints on cultured marine molluscs - a literature study

    OpenAIRE

    Heral, Maurice; Alzieu, Claude; Deslous-paoli, Jean-marc

    1989-01-01

    Organotin salts, used as antifouling substances have a deleterious effect on the environment particularly on molluscs and especially on the Japanese oyster Crassostrea gigas. A synthesis of the effects of tributyltin (TBT) on cultured molluscs reveals the following effects: 1) acute and chronic toxicity to the adults; 2) accumulation in the flesh 01 the adults; 3) perturbation 01 reproduction particularly fertility, mortality 01 offspring and decrease in larval growth rate; 4) decrease in the...

  12. Epigenetic features in the oyster Crassostrea gigas suggestive of functionally relevant promoter DNA methylation in invertebrates.

    Directory of Open Access Journals (Sweden)

    GuillaumeRiviere

    2014-04-01

    Full Text Available DNA methylation is evolutionarily conserved. Vertebrates exhibit high, widespread DNA methylation whereas invertebrate genomes are less methylated, predominantly within gene bodies. DNA methylation in invertebrates is associated with transcription level, alternative splicing and genome evolution, but functional outcomes of DNA methylation remain poorly described in lophotrochozoans. Recent genome-wide approaches improve understanding in distant taxa such as molluscs, where the phylogenetic position and life traits of Crassostrea gigas make this bivalve an ideal model to study the physiological and evolutionary implications of DNA methylation. We review the literature about DNA methylation in invertebrates and focus on DNA methylation features in the oyster. Indeed, though our MeDIP-seq results confirm predominant intragenic methylation, the profiles depend on the oyster’s developmental and reproductive stage. We discuss the perspective that oyster DNA methylation could be biased toward the 5’-end of some genes, depending on physiological status, suggesting important functional outcomes of putative promoter methylation from cell differentiation during early development to sustained adaptation of the species to the environment.

  13. Numerical Quantification of Perkinsus Marinus in the American Oyster Crassostrea virginicata (Gmelin 1791) (Mollusca: Bivalvia) by Modern Stereology

    Science.gov (United States)

    Species of Perkinsus are responsible for high mortalities of bivalve molluscs world-wide. Techniques to accurately estimate parasites in tissues are required to improve understanding of perkinsosis. This study quantifies the number and tissue distribution of Perkinsus marinus in ...

  14. "Protected" marine shelled molluscs: thriving in Greek seafood restaurants

    OpenAIRE

    S. KATSANEVAKIS; D. POURSANIDIS; Y. ISSARIS; A. PANOU; D. PETZA; Vassilopoulou, V.; I. CHALDAIOU; M. SINI

    2012-01-01

    International agreements as well as European and national legislation prohibit exploitation and trading of a number of edible marine shelled molluscs, due to either significant declines in their populations or destructive fishing practices. However, enforcement of existing legislation in Greece is ineffective and many populations of “protected” species continue to decline, mainly due to poaching. The extent of illegal trading of protected bivalves and gastropods in Greek seafood restaurants w...

  15. Indian marine bivalves: Potential source of antiviral drugs

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A.; Ansari, Z.A.; Ingole, B.S.; Bichurina, M.A.; Sovetova, M.; Boikov, Y.A.

    ( Crassostrea gryphoides ) and clam (Meretrix casta , M. meretrix , Paphia malabarica , Villorita cypr i noides ) . Recent investigations conducted jointly by Russian and Indian scientists showed that Indian green mussels ( P. viridis... prophyla c tic effect has been observed in mice when a dose of mussel extract was given 5 h before inoculation of v i rus 3 and the mice showed 100% survival. Marine bivalves are filter - feeding animals, and while feeding they accumulate...

  16. Patterns of DNA Barcode Variation in Canadian Marine Molluscs

    Science.gov (United States)

    Layton, Kara K.S.; Martel, André L.; Hebert, Paul DN.

    2014-01-01

    Background Molluscs are the most diverse marine phylum and this high diversity has resulted in considerable taxonomic problems. Because the number of species in Canadian oceans remains uncertain, there is a need to incorporate molecular methods into species identifications. A 648 base pair segment of the cytochrome c oxidase subunit I gene has proven useful for the identification and discovery of species in many animal lineages. While the utility of DNA barcoding in molluscs has been demonstrated in other studies, this is the first effort to construct a DNA barcode registry for marine molluscs across such a large geographic area. Methodology/Principal Findings This study examines patterns of DNA barcode variation in 227 species of Canadian marine molluscs. Intraspecific sequence divergences ranged from 0–26.4% and a barcode gap existed for most taxa. Eleven cases of relatively deep (>2%) intraspecific divergence were detected, suggesting the possible presence of overlooked species. Structural variation was detected in COI with indels found in 37 species, mostly bivalves. Some indels were present in divergent lineages, primarily in the region of the first external loop, suggesting certain areas are hotspots for change. Lastly, mean GC content varied substantially among orders (24.5%–46.5%), and showed a significant positive correlation with nearest neighbour distances. Conclusions/Significance DNA barcoding is an effective tool for the identification of Canadian marine molluscs and for revealing possible cases of overlooked species. Some species with deep intraspecific divergence showed a biogeographic partition between lineages on the Atlantic, Arctic and Pacific coasts, suggesting the role of Pleistocene glaciations in the subdivision of their populations. Indels were prevalent in the barcode region of the COI gene in bivalves and gastropods. This study highlights the efficacy of DNA barcoding for providing insights into sequence variation across a broad

  17. Domoic acid analysis in bivalve molluscs. Seafoodplus traceability

    OpenAIRE

    Etienne, Monique

    2006-01-01

    Domoic acid (DA) was identified as the toxin responsible for an outbreak of illness in Canada in 1987, caused by eating blue mussels that had accumulated DA as a result of the presence of Pseudo-nitzschia pungens. It is named amnesic shellfish poisoning (ASP). Since a regulatory level of 20 mg DA/kg of shellfish meat was established. The methods of determination of domoic acid are reviewed: biological assays in vivo and in vitro, biochemical and chemical assays. The AOAC mouse bioassay, which...

  18. Insights into shell deposition in the Antarctic bivalve Laternula elliptica: gene discovery in the mantle transcriptome using 454 pyrosequencing

    Directory of Open Access Journals (Sweden)

    Power Deborah M

    2010-06-01

    Full Text Available Abstract Background The Antarctic clam, Laternula elliptica, is an infaunal stenothermal bivalve mollusc with a circumpolar distribution. It plays a significant role in bentho-pelagic coupling and hence has been proposed as a sentinel species for climate change monitoring. Previous studies have shown that this mollusc displays a high level of plasticity with regard to shell deposition and damage repair against a background of genetic homogeneity. The Southern Ocean has amongst the lowest present-day CaCO3 saturation rate of any ocean region, and is predicted to be among the first to become undersaturated under current ocean acidification scenarios. Hence, this species presents as an ideal candidate for studies into the processes of calcium regulation and shell deposition in our changing ocean environments. Results 454 sequencing of L. elliptica mantle tissue generated 18,290 contigs with an average size of 535 bp (ranging between 142 bp-5.591 kb. BLAST sequence similarity searching assigned putative function to 17% of the data set, with a significant proportion of these transcripts being involved in binding and potentially of a secretory nature, as defined by GO molecular function and biological process classifications. These results indicated that the mantle is a transcriptionally active tissue which is actively proliferating. All transcripts were screened against an in-house database of genes shown to be involved in extracellular matrix formation and calcium homeostasis in metazoans. Putative identifications were made for a number of classical shell deposition genes, such as tyrosinase, carbonic anhydrase and metalloprotease 1, along with novel members of the family 2 G-Protein Coupled Receptors (GPCRs. A membrane transport protein (SEC61 was also characterised and this demonstrated the utility of the clam sequence data as a resource for examining cold adapted amino acid substitutions. The sequence data contained 46,235 microsatellites and 13

  19. The Bivalve Yangtzedonta is not the Brachiopod Xianfengella

    Institute of Scientific and Technical Information of China (English)

    YU Wen

    2005-01-01

    The alleged "holotype" of the bivalve Yangtzedontaprimitiva Yu, 1985 figured by Qian (2001) is a broken and distorted specimen of the brachiopod Xianfengella prima He and Yang, 1982 and not the holotype of Y. primitiva. Qian contends that the oldest recognized monoplacophoran, Maikhanella pristinis (Jiang, 1980), is neither a monoplacophoran nor the oldest molluscan fossil in the Meishucunian Stage of China. Furthermore, he considers that the oldest bivalve Xianfengoconcha elliptica Zhang, 1980 is an inarticulate brachiopod, not a mollusc. Watsonella yunnanensis (He and Yang, 1982), is associated with Yangtzedonta primitiva Yu but indicates no evolutionary relationship between the Classes Rostroconchia and Bivalvia in the Lower Cambrian Zhongyicun Member of the Yuhucun Formation. Qian's confusion in using non-molluscan fossils to discuss the early evolution of shelled molluscs also confuses the basic concepts of the respective groups.

  20. Indole pigments of molluscs

    OpenAIRE

    Verhecken, A.

    1989-01-01

    This study discusses occurrence and biosynthesis of melanins and indigoids, pigments with indole structure produced by Mollusca. Indigotin and 6,6'-dibromoindigotin (DBI), constituents of mollusc purple, are treated in some detail. Their colourless precursors in the organism are presumed to be of dietary origin. The hypothesis is formulated that formation of DBI is due to a detoxification mechanism; it is suggested that purple-producing species have developed it into an enzymatically controll...

  1. A Bivalve Proxy for Neogene Antarctic Shelf Marine Environments

    Science.gov (United States)

    Clark, N. A.; Williams, M.; Quilty, P. G.; Leng, M. J.; Zalasiewicz, J. A.; Smellie, J.; Dowsett, H. J.

    2012-12-01

    The Neogene shallow-marine successions of the Antarctic Peninsula and of the East Antarctic region preserve rich assemblages of bivalve molluscs. These bivalve molluscs provide a detailed record of palaeoseasonality in the chemical signature and morphology of their shells that can be used to assess sea temperatures and sea ice extent for the Antarctic shelf during the Pliocene. Analyses identify the following. 1) Neogene bivalves from James Ross Island, Antarctic Peninsula, comprise material of late Miocene through to late Pliocene age. Results identify warm (ca. 3-10 °C) early Pliocene sea temperatures, and cooler late Pliocene sea temperatures (ca. 0-4 °C), and flag a cooling trend which is consistent with the evolution of polar climate through this interval. 2) Neogene bivalves from the Larsemann Hills, East Antarctic, identify generally warmer than present sea temperatures (ca. 0-11 °C) in the early Pliocene consistent with data from other fossil groups of this age, including dolphins and silicoflagellates. The new data may provide significant ground truth for climate models assessing the Southern Ocean and Antarctic shelf climate.

  2. Freshwater bivalve mollusca (unionidae, sphaeriidae, corbiculidae) of the Savannah River Plant, South Carolina

    International Nuclear Information System (INIS)

    A guide to freshwater bivalve molluscs found at the Savannah River Plant is presented. A dichotomous taxonomic key is provided to common forms and to unreported species whose geographic distributions include nearby localities. Discussions of ecology, life history, larval hosts, and other pertinent information is provided

  3. Modelling isotopes dynamics in soft tissues of Crassostrea gigas in the context of DEB theory to study the trophic ecology of oysters at large spatial scale

    OpenAIRE

    Emmery, Antoine; LEFEBVRE, Sebastien; ALUNNO-BRUSCIA, Marianne; Kooijman, S. A. L. M.

    2009-01-01

    Biological performances (growth and reproduction) of intertidal bivalves mainly rely on environmental factors such as water temperature and food sources. Both quality and quantity of bivalve food sources, however, are not easy to determine because of complex features of coastal ecosystem functioning, such as high spatial heterogeneity. This is particularly critical for oyster (Crassostrea gigas) culture in France when quantifying and explaining the variability in growth performances of oyster...

  4. Identification and Functional Characterization of Two Executioner Caspases in Crassostrea gigas

    OpenAIRE

    Tao Qu; Baoyu Huang; Linlin Zhang; Li Li; Fei Xu; Wen Huang; Chunyan Li; Yishuai Du; Guofan Zhang

    2014-01-01

    Caspase-3 and caspase-7 are two key effector caspases that play important roles in apoptotic pathways that maintain normal tissue and organ development and homeostasis. However, little is known about the sequence, structure, activity, and function of effector caspases upon apoptosis in mollusks, especially marine bivalves. In this study, we investigated the possible roles of two executioner caspases in the regulation of apoptosis in the Pacific oyster Crassostrea gigas. A full-length caspase-...

  5. Evaluation of yolk protein as biomarkers for endocrine disruption in molluscs

    DEFF Research Database (Denmark)

    Morthorst, Jane Ebsen; Holbech, Henrik; Kinnberg, Karin Lund;

    in fish for decades. Vitellogenin (vtg) is mainly present in females, however, vtg synthesis can be induced by estrogens and EDCs in juveniles and males. During the last decade yolk protein has been used as biomarker in bivalve studies and alkali-labile phosphate (ALP) has been the applied method to...... indirectly estimate vtg levels. ALP was developed as an indirect method for determination of vtg in fish before more reliable and specific methods like ELISA (Enzyme-Linked Immuno Sorbent Assay) were developed. The use of yolk protein as biomarker in molluscs is based on the assumptions that vtg synthesis is...... biomarker for estrogenic exposure in molluscs by exposing the freshwater bivalve U. tumidus to 17β-estradiol (E2) (57, 164 and 512 ng/L) for eight weeks during their reproductive phase. Histological examination of the gonads revealed that E2 did not cause intersex and the ELISA revealed that the normal sex...

  6. Ostreid herpesvirus 1 detection and relationship with Crassostrea gigas spat mortality in France between 1998 and 2006

    OpenAIRE

    Garcia Céline; Thébault Anne; Dégremont Lionel; Arzul Isabelle; Miossec Laurence; Robert Maeva; Chollet Bruno; François Cyrille; Joly Jean-Pierre; Ferrand Sylvie; Kerdudou Nolwenn; Renault Tristan

    2011-01-01

    Abstract Since its molecular characterisation, Ostreid herpesvirus 1 (OsHV-1) has been regularly detected in Crassostrea gigas in France. Although its pathogenicity was demonstrated on larval stages, its involvement during mortality outbreaks at the juvenile stage was highly suspected but not evidenced. To investigate mortality outbreaks, the French National Network for Surveillance and Monitoring of Mollusc Health (REPAMO) carried out two surveys in juvenile C. gigas. The first survey lasted...

  7. Transmembrane myosin chitin synthase involved in mollusc shell formation produced in Dictyostelium is active

    Energy Technology Data Exchange (ETDEWEB)

    Schoenitzer, Veronika [INM - Leibniz Institute for New Materials, Biomineralisation Group, Campus D2.2, D-66123 Saarbruecken (Germany); Universitaet Regensburg, Biochemie I, Universitaetsstrasse 31, D-93053 Regensburg (Germany); Eichner, Norbert [Universitaet Regensburg, Biochemie I, Universitaetsstrasse 31, D-93053 Regensburg (Germany); Clausen-Schaumann, Hauke [Munich University of Applied Sciences, Lothstrasse 34, D-80335 Muenchen, Germany, and Center for NanoScience (CeNS), Geschwister-Scholl-Platz 1, D-80539 Muenchen (Germany); Weiss, Ingrid M., E-mail: ingrid.weiss@inm-gmbh.de [INM - Leibniz Institute for New Materials, Biomineralisation Group, Campus D2.2, D-66123 Saarbruecken (Germany); Universitaet Regensburg, Biochemie I, Universitaetsstrasse 31, D-93053 Regensburg (Germany)

    2011-12-02

    Highlights: Black-Right-Pointing-Pointer Dictyostelium produces the 264 kDa myosin chitin synthase of bivalve mollusc Atrina. Black-Right-Pointing-Pointer Chitin synthase activity releases chitin, partly associated with the cell surface. Black-Right-Pointing-Pointer Membrane extracts of transgenic slime molds produce radiolabeled chitin in vitro. Black-Right-Pointing-Pointer Chitin producing Dictyostelium cells can be characterized by atomic force microscopy. Black-Right-Pointing-Pointer This model system enables us to study initial processes of chitin biomineralization. -- Abstract: Several mollusc shells contain chitin, which is formed by a transmembrane myosin motor enzyme. This protein could be involved in sensing mechanical and structural changes of the forming, mineralizing extracellular matrix. Here we report the heterologous expression of the transmembrane myosin chitin synthase Ar-CS1 of the bivalve mollusc Atrina rigida (2286 amino acid residues, M.W. 264 kDa/monomer) in Dictyostelium discoideum, a model organism for myosin motor proteins. Confocal laser scanning immunofluorescence microscopy (CLSM), chitin binding GFP detection of chitin on cells and released to the cell culture medium, and a radiochemical activity assay of membrane extracts revealed expression and enzymatic activity of the mollusc chitin synthase in transgenic slime mold cells. First high-resolution atomic force microscopy (AFM) images of Ar-CS1 transformed cellulose synthase deficient D. discoideumdcsA{sup -} cell lines are shown.

  8. Seston dynamics and bivalve feeding in the Bay of Marennes-Oléron (France)

    OpenAIRE

    Zurburg, Wouter; Smaal, Aad; Heral, Maurice; Dankers, Norbert

    1994-01-01

    Within the framework of an investigation into the carrying capacity of the Bay of Marennes-Oléron (France) for bivalve culture, the in situ uptake of suspended particulate material by oysters (Crassostrea gigas) and mussels (Mytilus edulis) was determined in experiments with benthic ecosystem tunnels. Very high fluctuations in seston quantity and quality were observed within and between tidal cycles. The percentage of organic carbon was inversely related to seston quantity at low concentratio...

  9. Collision patterns on mollusc shells

    OpenAIRE

    P. J. Plath; J. K. Plath; Schwietering, J.

    1997-01-01

    On mollusc shells one can find famous patterns. Some of them show a great resemblance to the soliton patterns in one-dimensional systems. Other look like Sierpinsky triangles or exhibit very irregular patterns. Meinhardt has shown that those patterns can be well described by reaction–diffusion systems [1]. However, such a description neglects the discrete character of the cell system at the growth front of the mollusc shell. We have therefore developed a one-dimensional cellular vector automa...

  10. Collision patterns on mollusc shells

    Directory of Open Access Journals (Sweden)

    P. J. Plath

    1997-01-01

    Full Text Available On mollusc shells one can find famous patterns. Some of them show a great resemblance to the soliton patterns in one-dimensional systems. Other look like Sierpinsky triangles or exhibit very irregular patterns. Meinhardt has shown that those patterns can be well described by reaction–diffusion systems [1]. However, such a description neglects the discrete character of the cell system at the growth front of the mollusc shell.

  11. Sediment core fossils in ancient Lake Ohrid: testing for faunal change in molluscs since the Last Interglacial period

    OpenAIRE

    Albrecht, C.; H. Vogel; Hauffe, T.; Wilke, T.

    2010-01-01

    Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harboring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date.

    For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200) from the nor...

  12. Etude des voies metaboliques des sucres chez l'huitre creuse crassostrea gigas. Implication dans les mortalites estivales.

    OpenAIRE

    Bacca, Helene

    2007-01-01

    Glycogen, the main form of glucose reserve in bivalves, is known to play a key energetic role in the Pacific oyster (Crassostrea gigas) annual reproduction cycle. The aim of this work was to study the pathways of glycogen synthesis and utilization in order to explain the relationships between energy, reproduction and oyster summer mortality events. We first characterized full length mRNA sequences of Glycogen synthase (Cg-GYS) and Glycogen phosphorylase (Cg-GPH). Biochemical determination of ...

  13. A DEB model to predict accumulation and detoxification of paralytic shellfish toxins by the Japanese Oyster (Crassostrea gigas)

    OpenAIRE

    Pousse, Emilien; Jean, Frédéric; ALUNNO-BRUSCIA, Marianne; Flye Sainte Marie, Jonathan

    2015-01-01

    France being the largest consumer of oysters in Europe, oyster farming is deeply rooted in French heritage. The Japanese oyster (Crassostrea gigas) is the oyster species the most exploited in France, and in the world. Due to filter-feeding, these bivalves are sensitive to toxic algal blooms. Although not always lethal, toxic algae can affect oyster physiology and make it unfit for human consumption. Phytoplankton toxins can be classified in several groups: amnesic, neurotoxic, diarrhetic and ...

  14. The earliest post-paleozoic freshwater bivalves preserved in coprolites from the karoo basin, South Africa.

    Directory of Open Access Journals (Sweden)

    Adam M Yates

    Full Text Available BACKGROUND: Several clades of bivalve molluscs have invaded freshwaters at various times throughout Phanerozoic history. The most successful freshwater clade in the modern world is the Unionoida. Unionoids arose in the Triassic Period, sometime after the major extinction event at the End-Permian boundary and are now widely distributed across all continents except Antarctica. Until now, no freshwater bivalves of any kind were known to exist in the Early Triassic. PRINCIPAL FINDINGS: Here we report on a faunule of two small freshwater bivalve species preserved in vertebrate coprolites from the Olenekian (Lower Triassic of the Burgersdorp Formation of the Karoo Basin, South Africa. Positive identification of these bivalves is not possible due to the limited material. Nevertheless they do show similarities with Unionoida although they fall below the size range of extant unionoids. Phylogenetic analysis is not possible with such limited material and consequently the assignment remains somewhat speculative. CONCLUSIONS: Bivalve molluscs re-invaded freshwaters soon after the End-Permian extinction event, during the earliest part of the recovery phase during the Olenekian Stage of the Early Triassic. If the specimens do represent unionoids then these Early Triassic examples may be an example of the Lilliput effect. Since the oldest incontrovertible freshwater unionoids are also from sub-Saharan Africa, it is possible that this subcontinent hosted the initial freshwater radiation of the Unionoida. This find also demonstrates the importance of coprolites as microenvironments of exceptional preservation that contain fossils of organisms that would otherwise have left no trace.

  15. Molluscs and echinoderms aquaculture: biological aspects, current status, technical progress and future perspectives for the most promising species in Italy

    OpenAIRE

    Antonio Pais; Alessandra Roncarati; Genciana Terova; Giovanni Piccolo; Laura Gasco; Gerardo Centoducati; Giuliana Parisi; Pier Paolo Gatta; Vittorio Maria Moretti

    2012-01-01

    Shellfish aquaculture is a widespread activity in the Italian peninsula. However, only two bivalve species are mainly cultured along the coastline of that country: the Mediterranean mussel Mytilus galloprovincialis and the Manila clam Venerupis philippinarum (Ruditapes philippinarum). By contrast, just a few other mollusc species of commercial interest are scarcely reared at a small-scale level. After analysing the current status of Italian shellfish production, this paper reports and discuss...

  16. "Protected" marine shelled molluscs: thriving in Greek seafood restaurants

    Directory of Open Access Journals (Sweden)

    S. KATSANEVAKIS

    2012-12-01

    Full Text Available International agreements as well as European and national legislation prohibit exploitation and trading of a number of edible marine shelled molluscs, due to either significant declines in their populations or destructive fishing practices. However, enforcement of existing legislation in Greece is ineffective and many populations of “protected” species continue to decline, mainly due to poaching. The extent of illegal trading of protected bivalves and gastropods in Greek seafood restaurants was investigated by interviewing owners or managers of 219 such restaurants in 92 localities. Interviews were based on questionnaires regarding the frequency of availability in the menus and the origin of twenty-one species or groups of species, among which eight are protected - illegally exploited. Forty-two percent of the surveyed restaurants were found to serve at least one of the protected ¬- illegally exploited species. Among the illegally traded species, Lithophaga lithophaga, Pecten jacobaeus, and Pinnanobilis were served in a relatively high proportion of the surveyed restaurants (22.8%, 19.2%, and 16.4% respectively, outrunning many commercial species. In many cases these species were always or often available (11.4%, 4.6% and 5.0% respectively. There was substantial spatial variation in the proportion of restaurants that illegally served protected species with differing patterns for each species; very high proportions of illegal trading were observed in some marine regions (e.g., date mussels were served in >65% of the seafood restaurants along the coastline of Evvoikos Gulf. In most cases the illegally traded species were of local origin, while there was no finding of illegally imported molluscs from other countries. The strategy for enforcement of existing legislation should be greatly improved otherwise protection of shelled molluscs will remain ineffective.

  17. Biodiversity of trematodes in their intermediate mollusc and fish hosts in the freshwater ecosystems of Europe.

    Science.gov (United States)

    Faltýnková, Anna; Sures, Bernd; Kostadinova, Aneta

    2016-03-01

    We analysed two novel databases containing 2,380 and 8,202 host-parasite-locality records for trematode parasites of molluscs and fishes, respectively, to assess the biodiversity of trematodes in their intermediate mollusc and fish hosts in the freshwater environment in Europe. The "mollusc" dataset covers large numbers of pulmonate (29 spp.), "prosobranch" (15 spp.) and bivalve (11 spp.) molluscs acting as first intermediate hosts for 171 trematode species of 89 genera and 35 families. Of these, 23 and 40 species utilise freshwater fishes as definitive and second intermediate hosts, respectively. The most frequently recorded families are the Echinostomatidae Looss, 1899, Diplostomidae Poirier, 1886 and Schistosomatidae Stilles & Hassal, 1898, and the most frequently recorded species are Diplostomum spathaceum (Rudolphi, 1819), D. pseudospathaceum Niewiadomska, 1984 and Echinoparyphium recurvatum (von Linstow, 1873). Four snail species harbour extremely rich trematode faunas: Lymnaea stagnalis (L.) (41 spp.); Planorbis planorbis (L.) (39 spp.); Radix peregra (O.F. Müller) (33 spp.); and R. ovata (Draparnaud) (31 spp.). The "fish" dataset covers 99 fish species of 63 genera and 19 families acting as second intermediate hosts for 66 species of 33 genera and nine families. The most frequently recorded families are the Diplostomidae Poirier, 1886, Strigeidae Railliet, 1919 and Bucephalidae Poche, 1907, and the most frequently recorded species are Diplostomum spathaceum (Rudolphi, 1819), Tylodelphys clavata (von Nordmann, 1832) and Posthodiplostomum cuticola (von Nordmann, 1832). Four cyprinid fishes exhibit the highest species richness of larval trematodes: Rutilus rutilus (L.) (41 spp.); Abramis brama (L.) (34 spp.); Blicca bjoerkna (L.) (33 spp.); and Scardinius erythrophthalmus (L.) (33 spp.). Larval stages of 50 species reported in fish are also reported in freshwater molluscs, thus indicating a relatively good knowledge of the life-cycles of fish trematodes in

  18. Transplant rejection in terrestrial molluscs

    OpenAIRE

    E Furuta; Yamaguchi, K

    2011-01-01

    To know whether or not molluscs are capable of recognizing tissue allo-antigens, dorsal skin-allografts were exchanged between adult terrestrial slug, Incilaria fruhstorferi. We succeeded for the first time in orthotopic transplantation of allografts and observed chronic rejection of allografts. Cellular changes in the rejection process continued over for 40 days. Two functional types of “effector” cells were recognized at the rejection site, but they were observed to be macrophages possessin...

  19. Differential concentration of Technetium-99 (99Tc) in common intertidal molluscs with different food habits

    International Nuclear Information System (INIS)

    Highlights: → 99Tc-concentrations were measured in fucoids and four mollusc species. → Study was done in an intertidal locality on the southwestern coast of Norway. → The results showed that the 99Tc-concentrations differed between the mollusc species. → Fucoids at the locality showed very high 99Tc-concentrations. → Highest 99Tc-concentrations in the herbivorous gastropods Patella vulgata and Littorina obtusata. - Abstract: Concentration of 99Tc has been measured in fucoids and molluscs, sampled in a sheltered intertidal at the southwest coast of Norway from February to November 2006. The concentrations of 99Tc in molluscs differed significantly between species. The filtering bivalve Mytilus edulis had the lowest concentrations with averages of 2.3-5.9 Bq kg-1 d.w., while the herbivorous gastropods Littorinalittorina, Littorina obtusata and Patella vulgata had higher concentrations. P. vulgata and L. obtusata had the highest concentrations, 40-47 and 26-30 Bq kg-1 d.w., respectively. L. obtusata has a specialized habit of living, and prefers to feed on fucoids. P. vulgata can graze extensively on the fucoid Ascophyllum nodosum when available. Fucoids are known to have very high uptake of 99Tc, and this was also found in the present study. The high 99Tc-concentrations of L. obtusata and P. vulgata are most likely due to their habit of feeding on fucoids.

  20. Sediment core fossils in ancient Lake Ohrid: testing for faunal change in molluscs since the Last Interglacial period

    Directory of Open Access Journals (Sweden)

    C. Albrecht

    2010-05-01

    Full Text Available Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harboring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date.

    For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200 from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR dating of mollusc shells from the same stratigraphic level yielded an age of 130±28 ka. Lithofacies III sediments, i.e. a subdivision of the stratigraphic unit comprising the basal succession of core Co1200 between 181.5–263 cm appeared solid, grayish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO3>70% and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated. The agreement between sediment and palaeontological proxies was tested. The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial period.

    We tested for major faunal changes since the Last Interglacial period and searched for signs of extinction events. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5–25 m mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid sediment cores also

  1. Sediment core fossils in ancient Lake Ohrid: testing for faunal change in molluscs since the Last Interglacial period

    Science.gov (United States)

    Albrecht, C.; Vogel, H.; Hauffe, T.; Wilke, T.

    2010-05-01

    Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harboring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date. For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200) from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR) dating of mollusc shells from the same stratigraphic level yielded an age of 130±28 ka. Lithofacies III sediments, i.e. a subdivision of the stratigraphic unit comprising the basal succession of core Co1200 between 181.5-263 cm appeared solid, grayish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO3>70%) and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species) could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated. The agreement between sediment and palaeontological proxies was tested. The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial period. We tested for major faunal changes since the Last Interglacial period and searched for signs of extinction events. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5-25 m) mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid sediment cores also has great significance for future deep drilling

  2. Trace metals in bivalves and seagrass collected from Venezuelan coastal sites

    International Nuclear Information System (INIS)

    Ti vela mactroides and Crassostrea rhizophorae are two abundant species of bivalves along the Venezuelan coast and high local demand as seafood. The seagrass Thalassia testudinum, of interest in different parts of the world, is very abundant in coastal areas of Venezuela. The concentrations of Cd, Cr, Cu, Ni, V and Zn are reported in samples of soft tissue of Tivela mactroides and Crassostrea rhizophorae and tissues of Thalassia testudinum, collected along the Venezuelan coast. These metal concentrations were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Statistical analysis (one-way ANOVA) indicated that the species under consideration have different characteristics compared to metal bioaccumulation and could be used as potential indicators to investigate contamination by trace metals. (author)

  3. Pacific cupped oyster - Crassostrea gigas

    OpenAIRE

    Lapegue, Sylvie; Boudry, Pierre; Goulletquer, Philippe

    2006-01-01

    Originating from the north eastern Asia, Crassostrea gigas is endemic to Japan, but has been introduced and translocated, mainly for aquaculture purpose, into several countries, almost worldwide (1). In North America, the species can be found from Southeast Alaska to Baja California, while in European waters the species is cultured from Norway to Portugal as well as in Mediterranean Sea (Fig.1) (2). Biological characteristics make it suitable for a wide range of environmental conditions, alth...

  4. Moluscos bivalves em Portugal: composição química e metais contaminantes

    OpenAIRE

    Oliveira, Maria Cidália Rodrigues Mendes de

    2012-01-01

    A cultura e consumo de moluscos bivalves em Portugal são atividades cujo início se perde no tempo e com um grande impacto na economia nacional. Contudo, o consumo destes organismos envolve problemas específicos de segurança alimentar pelo que é necessário um controlo rigoroso associado a um plano de monitorização. A amêijoa japonesa (Ruditapes philippinarum), a ameijola (Callista chione), a lambujinha (Scrobicularia plana), o mexilhão (Mytilus edulis) e a ostra portuguesa (Crassostrea angu...

  5. Fatty acid compositions and trophic relationships of shelled molluscs from the Kuril-Kamchatka Trench and the adjacent abyssal plain

    Science.gov (United States)

    Kharlamenko, Vladimir I.; Würzberg, Laura; Peters, Janna; Borisovets, Evgeny E.

    2015-01-01

    Fatty acid (FA) compositions of 12 species of shelled molluscs (gastropods, bivalves, and scaphopods) from the Kuril-Kamchatka Trench and the adjacent abyssal plain were studied. According to the results of multivariate statistical analysis, molluscs were divided into three groups. Group I consisted of three scaphopod species, the bivalve Nucula profundorum and the gastropod Solariella delicata. FA compositions of this group were characterized by high levels of 20:4(n-6). We suggest that the FA pattern found in scaphopods with high values of 20:4(n-6) is most likely typical for that of benthic organisms feeding preferentially on foraminiferans. Group II included the bivalves Neilonella politissima, Bentharca asperula, and Rhinoclama filatovae. Bivalves from the second group had elevated concentrations of 22:6(n-3), and the ratio of 20:4(n-6) to 20:5(n-3) was lower than 1. Bivalves from the second group had elevated concentrations of 22:6(n-3). We propose that high concentrations of this FA can be used as a specific marker for a carnivorous feeding mode of deep-sea benthic invertebrates. The bivalve Bathyspinula calcarella as well as the scaphopod Polyschides sakuraii could not unambiguously be assigned to one group. Within the similarity analysis they rather clustered together with the foraminiferans feeders (group I), but forming an own subgroup. In the PCA on the other hand, P. sakuraii showed a position close to the other bivalves, while B. calcarella had an intermediate position between all three groups. Group III consisted of the gastropods Tacita holoserica and Paracteocina sp., which contained high concentrations of 20:5(n-3) and 22:5(n-3). Both are known to exhibit a carnivorous/scavenging feeding strategy. The very low content of DHA in both species is on first sight not consistent with the suggested carnivorous feeding behavior. A characteristic feature of Paracteocina sp. and T. holoserica was a high level of 22:5(n-3), and HUFA ratios indicate that DHA

  6. Cytotoxicity assessment of antibiofouling compounds and by-products in marine bivalve cell cultures.

    Science.gov (United States)

    Domart-Coulon, I; Auzoux-Bordenave, S; Doumenc, D; Khalanski, M

    2000-06-01

    Short-term primary cell cultures were derived from adult marine bivalve tissues: the heart of oyster Crassostrea gigas and the gill of clam Ruditapes decussatus. These cultures were used as experimental in vitro models to assess the acute cytotoxicity of an organic molluscicide, Mexel-432, used in antibiofouling treatments in industrial cooling water systems. A microplate cell viability assay, based on the enzymatic reduction of tetrazolium dye (MTT) in living bivalve cells, was adapted to test the cytotoxicity of this compound: in both in vitro models, toxicity thresholds of Mexel-432 were compared to those determined in vivo with classic acute toxicity tests. The clam gill cell model was also used to assess the cytotoxicity of by-products of chlorination, a major strategy of biofouling control in the marine environment. The applications and limits of these new in vitro models for monitoring aquatic pollutants were discussed, in reference with the standardized Microtox test. PMID:10806375

  7. The miRNA biogenesis in marine bivalves.

    Science.gov (United States)

    Rosani, Umberto; Pallavicini, Alberto; Venier, Paola

    2016-01-01

    Small non-coding RNAs include powerful regulators of gene expression, transposon mobility and virus activity. Among the various categories, mature microRNAs (miRNAs) guide the translational repression and decay of several targeted mRNAs. The biogenesis of miRNAs depends on few gene products, essentially conserved from basal to higher metazoans, whose protein domains allow specific interactions with dsRNA. Here, we report the identification of key genes responsible of the miRNA biogenesis in 32 bivalves, with particular attention to the aquaculture species Mytilus galloprovincialis and Crassostrea gigas. In detail, we have identified and phylogenetically compared eight evolutionary conserved proteins: DROSHA, DGCR8, EXP5, RAN, DICER TARBP2, AGO and PIWI. In mussels, we recognized several other proteins participating in the miRNA biogenesis or in the subsequent RNA silencing. According to digital expression analysis, these genes display low and not inducible expression levels in adult mussels and oysters whereas they are considerably expressed during development. As miRNAs play an important role also in the antiviral responses, knowledge on their production and regulative effects can shed light on essential molecular processes and provide new hints for disease prevention in bivalves. PMID:26989613

  8. Bivalve Omics: State of the Art and Potential Applications for the Biomonitoring of Harmful Marine Compounds

    Directory of Open Access Journals (Sweden)

    Paola Venier

    2013-11-01

    Full Text Available The extraordinary progress experienced by sequencing technologies and bioinformatics has made the development of omic studies virtually ubiquitous in all fields of life sciences nowadays. However, scientific attention has been quite unevenly distributed throughout the different branches of the tree of life, leaving molluscs, one of the most diverse animal groups, relatively unexplored and without representation within the narrow collection of well established model organisms. Within this Phylum, bivalve molluscs play a fundamental role in the functioning of the marine ecosystem, constitute very valuable commercial resources in aquaculture, and have been widely used as sentinel organisms in the biomonitoring of marine pollution. Yet, it has only been very recently that this complex group of organisms became a preferential subject for omic studies, posing new challenges for their integrative characterization. The present contribution aims to give a detailed insight into the state of the art of the omic studies and functional information analysis of bivalve molluscs, providing a timely perspective on the available data resources and on the current and prospective applications for the biomonitoring of harmful marine compounds.

  9. Molluscan biological and chemical diversity: secondary metabolites and medicinal resources produced by marine molluscs.

    Science.gov (United States)

    Benkendorff, Kirsten

    2010-11-01

    The phylum Mollusca represents an enormous diversity of species with eight distinct classes. This review provides a taxonomic breakdown of the published research on marine molluscan natural products and the medicinal products currently derived from molluscs, in order to identify priority targets and strategies for future research. Some marine gastropods and bivalves have been of great interest to natural products chemists, yielding a diversity of chemical classes and several drug leads currently in clinical trials. Molluscs also feature prominently in a broad range of traditional natural medicines, although the active ingredients in the taxa involved are typically unknown. Overall secondary metabolites have only been investigated from a tiny proportion (Polyplacophora, in particular, have been identified as worthy of future investigation given their use in traditional South African medicines and their abundance in littoral ecosystems. As bioactive compounds are not always constitutively expressed in molluscs, future research should be targeted towards biosynthetic organs and inducible defence reactions for specific medicinal applications. Given the lack of an acquired immune system, the use of bioactive secondary metabolites is likely to be ubiquitous throughout the Mollusca and broadening the search field may uncover interesting novel chemistry. PMID:20105155

  10. Bioactive potential of some intertidal molluscs collected from Mumbai coast,West coast of India

    Institute of Scientific and Technical Information of China (English)

    Atul G Babar; Anant Pande; Balasaheb G Kulkarni

    2012-01-01

    Objective: To identify the bioactive potential of crude methanolic extracts of five gastropods and one bivalve collected from the west coast of India (Mumbai coast). Methods: Disc-diffusion assay and micro-dilution technique were used to test the bioactive potential of these molluscs against six pathogenic bacteria. Results: The crude methanolic extracts of all the molluscs showed significant activity against one or more bacteria tested. Minimum inhibitory concentration of crude methanolic extracts was found in the range of 0.10–0.35 mg/mL against human pathogenic bacterial strains. Hemifusus pugilinus and Nerita sp. extracts were most effective showing activity against all bacterial strains. Hemifusus pugilinus extract exhibited good activity against Vibrio cholerae contrary to earlier reports. Methanolic extract of Gafrarium divaricatum demonstrated considerable activity against both Escherichia coli and Streptococcus pyogenes. Trochus radiatus extract was inactive against all the bacteria tested except Escherichiacoli. Euchelus asper extract was active against Klebsiella pneumoniae and Pseudomonas aeruginosa. Conclusions: All the molluscs screened exhibited potential activity against one or more bacterial strain. Further work is in progress to isolate the active constituents of the extracts.

  11. Molluscs production associated to lunar-tide cycle: a case study in Paraíba State under ethnoecology viewpoint

    Directory of Open Access Journals (Sweden)

    Alves Rômulo RN

    2006-06-01

    Full Text Available Abstract Molluscs have been for a long time a very important food resource for humans. Therefore, oysters, clams, and mussels are highly required at seafood markets. Like any commercial food, it is necessary that molluscs present good quality standards, concerning some criteria such as amount of meat and appearance. In bivalves, condition index or fattening index is considered a satisfactory method for estimating the amount of meat related to the shell cavity. Molluscs gatherers of Paraíba State coast, northeastern Brazil, state that molluscan meat production increases during spring tide (designated by them as maré de lançamento in opposition to the meat decrease which happens during neap tide (maré de quebramento (they are designated technically in Portuguese as maré de sizígia and maré de quadratura, respectively. Weperformed a survey on the production of unha-de-velho or 'oldman'snail' (Tagelus plebeius caught by molluscs gatherers in the estuary of River Paraíba do Norte, by observing locally their work, applying questionnaires, searching for a possible scientific relation of that molluscs condition to the gatherers empirical statement. Thus, we estimatedthe molluscs condition index through the method of solids percentage determination. We studied their work and the molluscs condition index during a full lunar-tide cycle. Determinations were carried out between 2nd September and 20th October, 1998, through 20 catches performed to obtain condition index from 400 bivalves. We observed that several biotic and abiotic ecological factors, namely reproduction cycle, biochemical components variations, animal size, and even parasitism, may affect the animal condition index. Despite this aspect, our present results confirmed a high overlapping (80% of the condition index curve with lunar-tide cycle, in agreement with the gatherers statement. Although we recognize the need for formulating and testing other hypotheses, we consider a priori that

  12. La Reproduction naturelle et contrôlée des bivalves cultivés en France. -Rapport de Groupe de Travail- IFREMER/Nantes/France, 14 et 15 novembre 1995

    OpenAIRE

    DEVAUCHELLE, Nicole; Barret, Jean; Salaun, Gilles

    1997-01-01

    This report compiles 17 short and illustrated syntheses concerning the natural strategies of reproduction and the artificial control of the reproductive process for the flat oyster, Ostrea edulis, the japanese oyster, Crassostrea gigas, the mussels, Mytilus edulis and My ti/us galloprovincialis, the scallop, Pecten maximus. An additional syntheses is presented, as a comparison within molluscs, which are the main research topics at IFREMER concerning the artificial control of the reproductive ...

  13. Is oxidative stress related to cadmium accumulation in the Mollusc Crassostrea angulata?

    International Nuclear Information System (INIS)

    Highlights: • The cadmium accumulation in C. angulata tended toward a stationary state. • Metallothionein-like protein (MTLP) is clearly induced by Cd accumulation. • The MTLP detoxification mechanism is affected at high Cd concentrations. • Cadmium toxicity causes GSH levels to decrease and inhibits antioxidant enzymes. - Abstract: The kinetics of cadmium (Cd) accumulation in the gills and digestive gland of Crassotrea angulata at three concentrations of cadmium (0.088 μM, 0.44 μM and 2.22 μM) was monitored for 28 days. The relationship between accumulation and toxicity was studied using metallothionein-like protein (MTLP) concentration and reduced glutathione levels (GSH) as biochemical endpoints. The activity of enzymes which form part of the antioxidant defense system, in particular glutathione reductase (GR), total glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT), as enzymatic endpoints, was also assessed. A first order kinetic model demonstrated that the accumulation process does not take place linearly, as the Cd concentration in gills and digestive gland tended toward a stationary state. Metallothionein-like protein is clearly induced by Cd accumulation; however, at high Cd concentrations the detoxification mechanism of this protein is affected. High Cd concentrations (2.22 μM) lead to a decrease in GSH levels, and also inhibit antioxidant enzyme activities, demonstrating the adverse effect of this metal on the antioxidant balance system

  14. Is oxidative stress related to cadmium accumulation in the Mollusc Crassostrea angulata?

    Energy Technology Data Exchange (ETDEWEB)

    Macías-Mayorga, Dayanara, E-mail: dayanara.macias@uleam.edu.ec [Instituto de Ciencias Marinas de Andalucía (CSIC), Campus Río San Pedro, S/N, 11510 Puerto Real, Cádiz (Spain); Departamento Central De Investigación (DCI), Universidad Laica Eloy Alfaro de Manabí, Vía San Mateo, Manta (Ecuador); Laiz, Irene [Departamento de Física Aplicada, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Río San Pedro, S/N, 11510 Puerto Real, Cádiz (Spain); Moreno-Garrido, Ignacio; Blasco, Julián [Instituto de Ciencias Marinas de Andalucía (CSIC), Campus Río San Pedro, S/N, 11510 Puerto Real, Cádiz (Spain)

    2015-04-15

    Highlights: • The cadmium accumulation in C. angulata tended toward a stationary state. • Metallothionein-like protein (MTLP) is clearly induced by Cd accumulation. • The MTLP detoxification mechanism is affected at high Cd concentrations. • Cadmium toxicity causes GSH levels to decrease and inhibits antioxidant enzymes. - Abstract: The kinetics of cadmium (Cd) accumulation in the gills and digestive gland of Crassotrea angulata at three concentrations of cadmium (0.088 μM, 0.44 μM and 2.22 μM) was monitored for 28 days. The relationship between accumulation and toxicity was studied using metallothionein-like protein (MTLP) concentration and reduced glutathione levels (GSH) as biochemical endpoints. The activity of enzymes which form part of the antioxidant defense system, in particular glutathione reductase (GR), total glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT), as enzymatic endpoints, was also assessed. A first order kinetic model demonstrated that the accumulation process does not take place linearly, as the Cd concentration in gills and digestive gland tended toward a stationary state. Metallothionein-like protein is clearly induced by Cd accumulation; however, at high Cd concentrations the detoxification mechanism of this protein is affected. High Cd concentrations (2.22 μM) lead to a decrease in GSH levels, and also inhibit antioxidant enzyme activities, demonstrating the adverse effect of this metal on the antioxidant balance system.

  15. Fracture mechanics of mollusc shells

    Energy Technology Data Exchange (ETDEWEB)

    Cortie, Michael B. [Institute for Nanoscale Technology, University of Technology, Sydney (Australia)]. E-mail: michael.cortie@uts.edu.au; McBean, Katie E. [Microstructural Analysis Unit, University of Technology, Sydney (Australia); Elcombe, Margaret M. [Bragg Institute, Australian Nuclear Science and Technology Organisation, PMB 1, NSW (Australia)

    2006-11-15

    The shape and structure of the shells of molluscs has attracted considerable attention. One aspect of interest is the comparatively high resistance to fracture of these shells. It is known that they are composite structures of aragonite, other calcereous materials, and up to 5% by volume of protein 'glue'. A large component of their toughening derives from crack tip blunting, deflection and closure, concepts well-known from the field of fracture mechanics. However, the possibility that they might also derive a measure of toughening from a residual stress distribution has been generally overlooked, although Illert first raised this over a decade ago. The optimum situation would be when the inner surface of the shell is maintained in a state of tensile stress, while the outer layers are in the necessarily counter-balancing compressive state. We have examined this hypothesis using a combination of neutron diffraction and scanning electron microscopy and find that it is certainly feasible. However, a definitive proof will require a diffraction study at higher resolution.

  16. Transplant rejection in terrestrial molluscs

    Directory of Open Access Journals (Sweden)

    E Furuta

    2011-01-01

    Full Text Available To know whether or not molluscs are capable of recognizing tissue allo-antigens, dorsal skin-allografts were exchanged between adult terrestrial slug, Incilaria fruhstorferi. We succeeded for the first time in orthotopic transplantation of allografts and observed chronic rejection of allografts. Cellular changes in the rejection process continued over for 40 days. Two functional types of “effector” cells were recognized at the rejection site, but they were observed to be macrophages possessing perforin granules and phagocytosing damaged cells of the allograft. Three days after transplantation, the perforin-positive cells were recognized only in the recipient tissue surrounding the allograft. Five days after transplantation, these cells started to appear in the graft, while they disappeared from the host tissue. However, TUNEL-positive cells (apoptotic cells were not observed throughout the graft-rejection process. Electron microscopic examination of the graft tissue revealed autophagic degeneration of epithelial cells, mucous cells, pigment cells, fibroblasts, and muscle cells. These observations suggest that the slugs have the capability to recognize differences in cell-surface molecules between the allogeneic and recipient tissue, and that an allograft is chronically rejected due to a type of immunocyte (macrophage that can induce perforin-dependent cell death

  17. Comparative Analysis and Distribution of Omega-3 lcPUFA Biosynthesis Genes in Marine Molluscs

    Science.gov (United States)

    Surm, Joachim M.; Prentis, Peter J.; Pavasovic, Ana

    2015-01-01

    Recent research has identified marine molluscs as an excellent source of omega-3 long-chain polyunsaturated fatty acids (lcPUFAs), based on their potential for endogenous synthesis of lcPUFAs. In this study we generated a representative list of fatty acyl desaturase (Fad) and elongation of very long-chain fatty acid (Elovl) genes from major orders of Phylum Mollusca, through the interrogation of transcriptome and genome sequences, and various publicly available databases. We have identified novel and uncharacterised Fad and Elovl sequences in the following species: Anadara trapezia, Nerita albicilla, Nerita melanotragus, Crassostrea gigas, Lottia gigantea, Aplysia californica, Loligo pealeii and Chlamys farreri. Based on alignments of translated protein sequences of Fad and Elovl genes, the haeme binding motif and histidine boxes of Fad proteins, and the histidine box and seventeen important amino acids in Elovl proteins, were highly conserved. Phylogenetic analysis of aligned reference sequences was used to reconstruct the evolutionary relationships for Fad and Elovl genes separately. Multiple, well resolved clades for both the Fad and Elovl sequences were observed, suggesting that repeated rounds of gene duplication best explain the distribution of Fad and Elovl proteins across the major orders of molluscs. For Elovl sequences, one clade contained the functionally characterised Elovl5 proteins, while another clade contained proteins hypothesised to have Elovl4 function. Additional well resolved clades consisted only of uncharacterised Elovl sequences. One clade from the Fad phylogeny contained only uncharacterised proteins, while the other clade contained functionally characterised delta-5 desaturase proteins. The discovery of an uncharacterised Fad clade is particularly interesting as these divergent proteins may have novel functions. Overall, this paper presents a number of novel Fad and Elovl genes suggesting that many mollusc groups possess most of the

  18. Investigating the impact of drilling mud and its major components on bivalve species of Georges Bank

    Energy Technology Data Exchange (ETDEWEB)

    1978-11-01

    The objective of this program has been to measure the response of commercially important marine bivalve molluscs to low levels of drilling muds. Because these materials are composed of several major components whose proportions vary between wells and with depth for a single well, the approach of this study has been to test the major components individually and then to test a representative synthetic mud and finally a used drilling mud from an offshore platform. In all but one of these tests the target organism has been the sea scallop, Placopecten magellanicus.

  19. Cellular and Transcriptional Responses of Crassostrea gigas Hemocytes Exposed in Vitro to Brevetoxin (PbTx-2

    Directory of Open Access Journals (Sweden)

    Alcir Luiz Dafre

    2012-03-01

    Full Text Available Hemocytes mediate a series of immune reactions essential for bivalve survival in the environment, however, the impact of harmful algal species and their associated phycotoxins upon bivalve immune system is under debate. To better understand the possible toxic effects of these toxins, Crassostrea gigas hemocytes were exposed to brevetoxin (PbTx-2. Hemocyte viability, monitored through the neutral red retention and MTT reduction assays, and apoptosis (Hoechst staining remained unchanged during 12 h of exposure to PbTx-2 in concentrations up to 1000 µg/L. Despite cell viability and apoptosis remained stable, hemocytes incubated for 4 h with 1000 µg/L of PbTx-2 revealed higher expression levels of Hsp70 (p < 0.01 and CYP356A1 ( p < 0.05 transcripts and a tendency to increase FABP expression, as evaluated by Real-Time quantitative PCR. The expression of other studied genes (BPI, IL-17, GSTO, EcSOD, Prx6, SOD and GPx remained unchanged. The results suggest that the absence of cytotoxic effects of PbTx-2 in Crassostrea gigas hemocytes, even at high concentrations, allow early defense responses to be produced by activating protective mechanisms associated to detoxification (CYP356A1 and possibly FABP and stress (Hsp70, but not to immune or to antioxidant (BPI, IL-17, EcSOD, Prx6, GPx and SOD related genes.

  20. Temporal distribution of heavy metal concentrations in oysters Crassostrea rhizophorae from the central Venezuelan coast.

    Science.gov (United States)

    Alfonso, Juan A; Handt, Helga; Mora, Abrahan; Vásquez, Yaneth; Azocar, José; Marcano, Eunice

    2013-08-15

    The oyster Crassostrea rhizophorae is a bivalve abundant in Venezuelan estuaries and consumed by local populations. No known values have been reported on trace metals in oysters from the central Venezuelan coast. We report the concentrations of Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V and Zn in the soft parts of C. rhizophorae, which were collected bimonthly between March 2008 and March 2009, at two sampling areas from the Central Venezuelan Coast: Buche estuary and Mochima estuary. Our results show that for each metal there is a similar temporal variation pattern. The concentrations of the heavy metals reported in this work are useful as reliable baselines and can be used for comparison in future environment studies. Concentrations in C. rhizophorae from the Buche estuary can be interpreted to be high on a global scale for Cd, Cu, Ni and Mn, indicating atypically raised bioavailabilities. PMID:23746942

  1. A Multi-module Approach to Calculation of Oyster ( Crassostrea virginica) Environmental Benefits

    Science.gov (United States)

    Cerco, Carl F.

    2015-08-01

    Environmental benefits are one of the motivations for management restoration of depleted bivalve populations. We describe a series of linked modules for benefits calculation. The modules include: oyster ( Crassostrea virginica) bioenergetics, materials transport via the tidal prism, and benefits quantification. Quantified benefits include carbon, nitrogen, and phosphorus removal and shell production. The modules are demonstrated through application to the Great Wicomico River, a tributary of Chesapeake Bay, USA. Oysters on seven reefs (total area 2.8 × 105 m2) are calculated to remove 15.2, 6.2, and 0.2 tons per annum of carbon, nitrogen, and phosphorus, respectively, from the Great Wicomico. Oyster mortality contributes 108 tons per annum dry weight shell to the reefs.

  2. Antioxidant defences role during post anoxic recovery in bivalve mollusc Scapharca inaequivalvis

    Directory of Open Access Journals (Sweden)

    J. Foschi

    2011-01-01

    Full Text Available Euryoxic organisms are able to withstand hypoxic conditions until the restoration of normal O2 levels, when the re-introduction of oxygen causes a decisive burst in reactive oxygen species (ROS. The consequent oxidative damage is countered by defence systems constituted by antioxidant enzymes, such as SOD, CAT, Se-GPx and G6PDH. Specimens of Scapharca inaequivalvis were exposed to anoxia for 3, 6 and 24 hours and subsequent reoxygenation for 1, 3, 5 and 24 hours. It has been investigated SOD, CAT, Se-GPx and G6PDH activity and MnSOD and CuZnSOD expression in the digestive gland. The results showed SODs activity to be high during both anoxia and reoxygenation. CAT and Se-GPx increase significantly overall during recovery. Only CuZnSOD expression was greater after 6 and 24 hours of anoxia. The presence of high levels of antioxidant enzymes during anozia suggests that the response of S. inaequivalvis is typical of euryoxic animals and represents an interesting model for studying the processes of ischaemia/reperfusion in mammals.

  3. Nucleosomal organization of chromatin in sperm nuclei of the bivalve mollusc Aulacomya ater.

    Science.gov (United States)

    Olivares, C; Ruiz, S

    1991-03-13

    The sperm nuclei of Aulacomya ater, family Mitylidae, contain three proteins (X, Aa5 and Aa6) which are specific to this cell type coexisting with a set of five somatic-type histones. Information about the chromatin structure resulting from this kind of association is scarce. Therefore, we have probed the structure of this sperm chromatin through digestion with micrococcal nuclease in combination with salt fractionation. The data obtained have allowed us to propose a nucleosomal arrangement for this chromatin. However, two types of nucleosomes would be present in agreement with their protein components. PMID:1861676

  4. Gynogenetic induction in marine bivalve molluscs for improvement of stocks: Standardization of some important factors

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, U.

    Experiments conducted for standardizing sperm density for artificial insemination of Chlamys mobilis prior to inducing gynogenesis by ultra-violet rays irradiated sperms showed that 10:1 ratio of sperms to eggs should be maintained for getting...

  5. Detection and quantification of Sapovirus in bivalve molluscs from Galicia (NW Spain.

    Directory of Open Access Journals (Sweden)

    Jesus L Romalde

    2014-06-01

    SaV was detected in 30 of the 168 samples (17,85%. There was no significant difference between the two Rías in terms of detections, although it was observed a seasonality increment of positive samples from November 2011 until April 2012 in both Rías due to the rainy season and the decrease of seawater temperature. Total quantification ranged between 103 and 105 copies of viral RNA/g of digestive tissue (c/g, being mussels the specie with lower main quantification (3,1 x 104 c/g and clams the species with higher medium rates (2,0 x 105 c/g. This represents the first study out of Japan in which human Sapovirus was detected and quantified into human food intended for consumption.

  6. Esterification of vertebrate like steroids in molluscs: a target of endocrine disruptors?

    Science.gov (United States)

    Giusti, Arnaud; Joaquim-Justo, Célia

    2013-11-01

    Alterations of the reproductive organs of gastropod molluscs exposed to pollutants have been reported in natural populations for more than 40 years. In some cases, these impacts have been linked to exposure to endocrine-disrupting chemicals (EDCs), which are known to induce adverse impacts on vertebrates, mainly by direct binding to steroid receptors or by altering hormone synthesis. Investigations on the mechanisms of action of endocrine disruptors in molluscs show that EDCs induce modifications of endogenous titres of androgens (e.g., testosterone, androstenedione) and oestrogens (e.g., 17ß-oestradiol). Alterations of the activity of enzymes related to steroid metabolism (i.e., cytochrome P-450 aromatase, acyltransferases) are also often observed. In bivalves and gastropods, fatty acid esterification of steroids might constitute the major regulation of androgen and oestrogen homeostasis. The present review indicates that metabolism of steroid hormones to fatty acid esters might be a target of synthetic EDCs. Alterations of this process would impact the concentrations of free, potentially bioactive, form of steroids. PMID:24004916

  7. The early radiation of stem group molluscs against the environmental background

    Science.gov (United States)

    Gubanov, A. P.

    2003-04-01

    The first helcionelloid molluscs appeared in the late Nemakit-Daldynian and were forerunners of the sudden molluscan diversification of the Cambrian explosion. The diversification of Mollusca is coincided with global changes in lithosphere, hydrosphere, atmosphere, and biosphere coincident with the rearrangement of the Late Proterozoic supercontinent Rodinia, a distinct shift in oceanic water geochemistry, and a sudden abundance of shelled multicellular organisms. Some of these changes have left indicators in the morphology and chemical properties of molluscan shells that allow reconstruction of global settings which are essential for understanding early molluscan evolution. A combination of tectonic and climatic cyclic changes is resulted in a major global transgression at the beginning of the Cambrian and the formation of extensive shallow water habitats within which the first molluscs expanded. Diversification into new ecological niches has been recognised in two evolutionary-adaptive lineages. The lineage from Oelandiella to Watsonella shows adaptation to a soft substrate and infaunal mode of life. In contrast, the Oelandiella-Helcionella lineage was an adaptation to a harder substrate. Appearance of large helcionelloids with associated archaeocyathan reefs in the middle Tommotian may suggest evolution of a browsing carnivorous habit capable of supporting a considerably larger body. Despite of a few such examples, most helcionelloids remained a small size until the Early Ordovician. Early Cambrian helcionelloids show considerable morphological diversity providing a fertile ground for speculation about early molluscan evolution. While almost the all molluscan classes are known from the Cambro-Ordovician transition, the relationship of these, including Tergomya, Gastropoda, Cephalopoda, and Rostroconchia to helcionelloids remains highly problematic. Analysis of morphological variation and evolutionary trends within the earliest molluscs may support derivation of

  8. Mollusc and brachiopod skeletal hardparts: Problematic archives of past seawater properties (Invited)

    Science.gov (United States)

    Immenhauser, A.; Schone, B. R.; Hoffmann, R.; Niedermayr, A.

    2013-12-01

    Biomineralized exo- or endoskeletons of fossil marine invertebrates are widespread and diverse components of the Phanerozoic rock record of Earth's past and present oceans. Exoskeletons serve as protection against environmental pressure or predators, whilst endoskeletons may act as support or serves as an attachment for muscles and ligaments and hence as a mechanism for transmitting muscular forces. Biogenic hardparts represent sophisticated products resulting from the hierarchical interaction of inorganic minerals (95%) and macromolecular organic matrix, forming commonly less than 5%. The significance of biogenic carbonate archives lies in the time-resolved growth-increments and their respective multi-proxy geochemical signatures that have been widely used to assess past oceanic seawater properties. We here compile and review published work dealing with crystallization pathways of skeletal hardparts secreted by molluscs (i.e., bivalves and cephalopods) as well as brachiopods as widely used archives of ancient neritic epeiric settings. Bivalves and cephalopods (e.g., extinct ammonoids and belemnites and extant Sepia, Nautilus and Spirula) all form accretionary calcitic, aragonitic or vateritic skeletal hardparts. Despite the fact that molluscs and brachiopods form part of very different branches of the animal phylogenetic tree, their biomineralization strategies are surprisingly similar. Our main focus lies in a critical assessment of the complex pathways of ions and aquo-complexes from their source (seawater) to the final product (biomineral). We do this as an attempt to critically test the commonly held hypothesis that many fossil shell hardparts precipitated, under favourable conditions and pending subsequent diagenetic alteration, in equilibrium with seawater. Two main observations stand out: (1) the present knowledge on pathways and mechanisms (e.g., ion channel trans-membrane or endocytosis and vesicle transport, precursor mineralogies etc.) is surprisingly

  9. Heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Molluscs are able to accumulate heavy metals and impose healthhazard to consumers. The main objective of the present study is to investigate the heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta. Fourteen species of edible molluscs were purchased from six markets in Hong Kong and Guangdong Province. The fresh of these biota were tested for their cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), antimony (Sb) and tin (Sn)concentrations (based on wet weight). The results indicated that amongst the 14 edible molluscs, only Cd, Pb, Ni, Cr, Sb and Sn concentrations in three species(Ruditapes philippinarum, Perna viridis and Hemifusus tuba) were within the local regulatory limits. Over 60% of bivalve species exceeded maximum permitted levels of Cd (2 μg/g) and Cr (1 μg/g), while over 40% of gastropod species exceeded the maximum levels of Sb (1 μg/g) and Cr(1 μg/g). Most of the samples collected from Hong Kong had significantly higher contents of Pb and Sb, but similar levels of Cd, Cu and Zn when compared with samples collected across the border (p<0.5; p<0.01; p<0.001 respectively). In general, the molluscs purchased in Guangdong markets had higher metal contents than those purchased from the Hong Kong markets. When compared with the Provisional Tolerable Weekly Intake or Maximum Acceptable Daily Load recommended by FAO/WHO Expert Committee on Food Additives, Cd levels of five species (Anadara ferruginea, Pinna pectinata, Chlamys nobilis, Babylonia lutosa and Hemifusus terntanus) and Cr levels of seven species (Anadara ferruginea, Paphia undulata, Pinna pectinata, Babylonia lutosa, Hemifusus terntanus, Cymbium melo and Cipangopaludina chinensis) were higher than both the human daily acceptable limits (for Cd and Cr respectively) and the local regulatory levels (for Cd and Cr respectively).

  10. Explosive demographic expansion by dreissenid bivalves as a possible result of astronomical forcing

    Directory of Open Access Journals (Sweden)

    M. Harzhauser

    2013-07-01

    Full Text Available Human induced range expansions of invasive dreissenid bivalves are of great concern. However, the underlying biological processes are only poorly understood, partly due to the lack of information on natural expansion events. Here we use the extinct bivalve species Sinucongeria primiformis as a model organism for testing natural (i.e. non-Anthropocene blooms of dreissenid species in a lacustrine system of Lake Pannon during the Tortonian (~10.5 Myr; Late Miocene. 600 samples from a consecutive core were evaluated for the relative abundance of this pavement-forming mollusc, which cover about 8 millennia of Late Miocene time with a decadal resolution. Our data indicate that the settlement by bivalves in the offshore environment was limited mainly by bottom water oxygenation, which follows predictable and repetitive patterns through time. These population fluctuations might be related to solar cycles: successful dreissenid settlement is re-occurring in a frequency known as the lower and upper Gleissberg cycles with a 50–80 and 90–120 yr period. These cycles appear to control regional wind patterns, which are directly linked to water mixing of the lake. This is modulated by the even more prominent 500 yr cycle, which seems to be the most important pacemaker for Lake Pannon hydrology.

  11. Malakofauna v nivě Jizery (Severní Čechy The mollusc fauna of the Jizera River floodplain (North Bohemia

    Directory of Open Access Journals (Sweden)

    Vojen Ložek

    2013-06-01

    Full Text Available This paper presents a research of floodplain mollusc communities of the Jizera River (the Elbe tributary, North Bohemia, Czech Republic. Altogether, 101 mollusc species (100 species of gastropods, one species of bivalve were recorded at 55 selected sites during previous and recent researches in 1945–1997 and 2002–2009, representing 40% of the total Czech malacofauna. The upper well-preserved stretch of the river hosts a rich forest mollusc fauna with some rare woodland species e.g. Arion intermedius, Cochlodina dubiosa corcontica, Daudebardia brevipes, D. rufa, Vertigo alpestris and Vitrea subrimata. Impoverish assemblages of the lower stretch are represented by some common or open/semi-open country species, because the river flows there through the landscape of an intensive agricultural land use and high settlement density. Despite, the occurrence of 31 rare species (four of them endangered, eight vulnerable, and 19 near threatened was recorded at the upper stretch of the Jizera River alluvium, which provides an important refuge for these mollusc faunas.

  12. Trace metal pollution and its influence on the community structure of soft bottom molluscs in intertidal areas of the Dar es Salaam coast, Tanzania

    International Nuclear Information System (INIS)

    The influence of trace metal pollution on the community structure of soft bottom molluscs was investigated in intertidal areas of the Dar es Salaam coast. Significant enrichment of As, Mn, Mo, Sb, and Zn in sediments was recorded. Redundancy analysis indicated that trace metal pollution contributed 68% of the variation in community structure. Monte Carlo permutation test showed that As and Sb contributed significantly to variation in species composition. T-value biplots and van Dobben circles showed that the gastropods Acteon fortis, Assiminea ovata, and Littoraria aberrans, were negatively affected by As and Sb, while the bivalve Semele radiata and the gastropod Conus litteratus were only negatively affected by As. Bioaccumulation of As, Cd, Cu, Mo and Zn occurred in the bivalve Mactra ovalina and the gastropod Polinices mammilla. This calls for regular monitoring and management measures.

  13. Galeommatid bivalves from Phuket, Thailand

    DEFF Research Database (Denmark)

    Lützen, Jørgen; Nielsen, Claus

    2005-01-01

    Twenty-seven species of galeommatid bivalves from six genera have been collected at intertidal reef flats near Phuket Marine Biological Center, Thailand (Andaman Sea, Indian Ocean). Fourteen of the species are new to science and a new genus (Nudiscintilla gen. nov.) has been established. The...... crustacean, the remainder hide under shale, rocks and coral blocks, often in small intra- or interspecific family flocks. The behaviour was also noted for some of the species. It is presumed that galeommatid species go through a lengthy planktonic phase....

  14. Neoplastic diseases of marine bivalves.

    Science.gov (United States)

    Carballal, María J; Barber, Bruce J; Iglesias, David; Villalba, Antonio

    2015-10-01

    Two types of prevalent neoplastic diseases have been described in marine bivalves of commercial interest: disseminated neoplasia (DN) and gonadal neoplasia. The first involves the excessive proliferation of abnormal cells with unknown origin (probably of hemic source in some cases/species), disseminating through the circulatory system and infiltrating the connective tissue of various organs; the second consists of an abnormal proliferation of undifferentiated germinal cells of the gonad. These two types of bivalve neoplasia fit the criteria of malignant tumors: pleomorphic and undifferentiated cells, rapid and invasive growth, abundance of mitotic figures, metastasis and progressive development often resulting in the death of the affected individual. Different causes have been suggested regarding etiology: genetic alterations, virus, retrotranspons, and contaminants, although it could depend on the mollusk species; evidence of horizontal transmission of clonal cancer cells as the cause of DN spreading in clam Mya arenaria populations has been recently reported. In some species and populations, the neoplastic disorders affect only a few individuals, but in others reach high prevalence. Among the diagnostic methods, DN has been detected by histology and cytologic examination of hemolymph, and with developed specific antibodies. Recently, flow cytometry has also been applied, allowing detecting DNA quantity alteration. Several studies reported many genes and pathways critically involved in neoplastic transformation in Mya arenaria, Mytilus spp. and Ostrea edulis. These genetic studies will allow the development of diagnosis by PCR which can be used in biomonitoring studies. PMID:26146225

  15. Characterization of reference genes for qPCR analysis in various tissues of the Fujian oyster Crassostrea angulata

    Science.gov (United States)

    Pu, Fei; Yang, Bingye; Ke, Caihuan

    2015-07-01

    Accurate quantification of transcripts using quantitative real-time polymerase chain reaction (qPCR) depends on the identification of reliable reference genes for normalization. This study aimed to identify and validate seven reference genes, including actin-2 ( ACT-2), elongation factor 1 alpha ( EF-1α), elongation factor 1 beta ( EF-1β), glyceraldehyde-3-phosphate dehydrogenase ( GAPDH), ubiquitin ( UBQ), β-tubulin ( β-TUB), and 18S ribosomal RNA, from Crassostrea angulata, a valuable marine bivalve cultured worldwide. Transcript levels of the candidate reference genes were examined using qPCR analysis and showed differential expression patterns in the mantle, gill, adductor muscle, labial palp, visceral mass, hemolymph and gonad tissues. Quantitative data were analyzed using the geNorm software to assess the expression stability of the candidate reference genes, revealing that β-TUB and UBQ were the most stable genes. The commonly used GAPDH and 18S rRNA showed low stability, making them unsuitable candidates in this system. The expression pattern of the G protein β-subunit gene ( Gβ) across tissue types was also examined and normalized to the expression of each or both of UBQ and β-TUB as internal controls. This revealed consistent trends with all three normalization approaches, thus validating the reliability of UBQ and β-TUB as optimal internal controls. The study provides the first validated reference genes for accurate data normalization in transcript profiling in Crassostrea angulata, which will be indispensable for further functional genomics studies in this economically valuable marine bivalve.

  16. Exposure to the Paralytic Shellfish Toxin Producer Alexandrium catenella Increases the Susceptibility of the Oyster Crassostrea gigas to Pathogenic Vibrios.

    Science.gov (United States)

    Abi-Khalil, Celina; Lopez-Joven, Carmen; Abadie, Eric; Savar, Veronique; Amzil, Zouher; Laabir, Mohamed; Rolland, Jean-Luc

    2016-01-01

    The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France), we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs), was concomitant with the accumulation of PSTs in oyster flesh and the occurrence of C. gigas mortalities. In order to investigate the possible role of toxic algae in this complex disease, we experimentally infected C. gigas oyster juveniles with Vibrio tasmaniensis strain LGP32, a strain associated with oyster summer mortalities, after oysters were exposed to Alexandrium catenella. Exposure of oysters to A. catenella significantly increased the susceptibility of oysters to V. tasmaniensis LGP32. On the contrary, exposure to the non-toxic dinoflagellate Alexandrium tamarense or to the haptophyte Tisochrysis lutea used as a foraging alga did not increase susceptibility to V. tasmaniensis LGP32. This study shows for the first time that A. catenella increases the susceptibility of Crassostrea gigas to pathogenic vibrios. Therefore, in addition to complex environmental factors explaining the mass mortalities of bivalve mollusks, feeding on neurotoxic dinoflagellates should now be considered as an environmental factor that potentially increases the severity of oyster mortality events. PMID:26784228

  17. Exposure to the Paralytic Shellfish Toxin Producer Alexandrium catenella Increases the Susceptibility of the Oyster Crassostrea gigas to Pathogenic Vibrios

    Directory of Open Access Journals (Sweden)

    Celina Abi-Khalil

    2016-01-01

    Full Text Available The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France, we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs, was concomitant with the accumulation of PSTs in oyster flesh and the occurrence of C. gigas mortalities. In order to investigate the possible role of toxic algae in this complex disease, we experimentally infected C. gigas oyster juveniles with Vibrio tasmaniensis strain LGP32, a strain associated with oyster summer mortalities, after oysters were exposed to Alexandrium catenella. Exposure of oysters to A. catenella significantly increased the susceptibility of oysters to V. tasmaniensis LGP32. On the contrary, exposure to the non-toxic dinoflagellate Alexandrium tamarense or to the haptophyte Tisochrysis lutea used as a foraging alga did not increase susceptibility to V. tasmaniensis LGP32. This study shows for the first time that A. catenella increases the susceptibility of Crassostrea gigas to pathogenic vibrios. Therefore, in addition to complex environmental factors explaining the mass mortalities of bivalve mollusks, feeding on neurotoxic dinoflagellates should now be considered as an environmental factor that potentially increases the severity of oyster mortality events.

  18. Assessment of arsenic in coastal sediments, seawaters and molluscs in the Tarut Island, Arabian Gulf, Saudi Arabia

    Science.gov (United States)

    El-Sorogy, Abdelbaset S.; Youssef, Mohamed; Al-Kahtany, Khaled; Al-Otaiby, Naif

    2016-01-01

    In order to assess arsenic on the Tarut coast, Saudi Arabian Gulf, 38 sediment samples, 26 seawater samples and 40 gastropod and bivalve specimens were collected for analyses by Inductively Coupled Plasma-Mass Spectrometer. The Enrichment Factor (EF), the Geoaccumulation Index (Igeo) and the Contamination Factor (CF) indicated that coastal sediments of Tarut Island are severely enriched, strongly polluted and very highly contaminated with arsenic as a result of anthropogenic inputs. Comparison with arsenic in coastal sediments, seawaters and molluscs in the Red Sea, the Arabian Gulf and abroad coasts suggested that the studied samples have higher concentrations of As. The suggested natural sources of arsenic in the study area are the weathering and decomposition of neighboring deserts. The anthropogenic sources include the land reclamation, petrochemical industries, boat exhaust emissions, oil leakage, desalination plants and sewage effluents. These anthropogenic sources are the dominant sources of As in the study area and mostly came from Al Jubail industrial city to the north.

  19. A glutamic acid decarboxylase (CgGAD) highly expressed in hemocytes of Pacific oyster Crassostrea gigas.

    Science.gov (United States)

    Li, Meijia; Wang, Lingling; Qiu, Limei; Wang, Weilin; Xin, Lusheng; Xu, Jiachao; Wang, Hao; Song, Linsheng

    2016-10-01

    Glutamic acid decarboxylase (GAD), a rate-limiting enzyme to catalyze the reaction converting the excitatory neurotransmitter glutamate to inhibitory neurotransmitter γ-aminobutyric acid (GABA), not only functions in nervous system, but also plays important roles in immunomodulation in vertebrates. However, GAD has rarely been reported in invertebrates, and never in molluscs. In the present study, one GAD homologue (designed as CgGAD) was identified from Pacific oyster Crassostrea gigas. The full length cDNA of CgGAD was 1689 bp encoding a polypeptide of 562 amino acids containing a conserved pyridoxal-dependent decarboxylase domain. CgGAD mRNA and protein could be detected in ganglion and hemocytes of oysters, and their abundance in hemocytes was unexpectedly much higher than those in ganglion. More importantly, CgGAD was mostly located in those granulocytes without phagocytic capacity in oysters, and could dynamically respond to LPS stimulation. Further, after being transfected into HEK293 cells, CgGAD could promote the production of GABA. Collectively, these findings suggested that CgGAD, as a GABA synthase and molecular marker of GABAergic system, was mainly distributed in hemocytes and ganglion and involved in neuroendocrine-immune regulation network in oysters, which also provided a novel insight to the co-evolution between nervous system and immune system. PMID:27208883

  20. Extraction and Identification of the Pigment in the Adductor Muscle Scar of Pacific Oyster Crassostrea gigas.

    Directory of Open Access Journals (Sweden)

    Shixin Hao

    Full Text Available In this study, UV (ultraviolet and IR (infrared radiation spectral analysis were integrated to identify the pigment in the adductor muscle scar of the Pacific oyster Crassostrea gigas. The pigment was extracted from the adductor muscle scars of cleaned oyster shells that were pulverized, hydrolyzed in hot hydrochloric acid, purified with diethyl ether, and dissolved in 0.01 mL/L NaOH. The maximum absorption of the pigment in the UV absorption spectrum within the range of 190-500 nm was observed between 210-220 nm. The UV absorbance decreased with increasing wavelength which was consistent with the UV spectral absorption characteristics of melanin. In addition, Fourier transform infrared spectroscopy scanning revealed characteristic absorption peaks that emerged near 3440 cm-1 and 1630 cm-1, which was consistent with infrared scanning features of eumelanin (a type of melanin. This study has demonstrated for the first time that the pigment in the adductor muscle scar of the Pacific oyster is melanin, hinting that the adductor muscle could be another organ pigmenting the mollusc shell with melanin other than mantle.

  1. Transcriptomic response to stress in marine bivalves

    Directory of Open Access Journals (Sweden)

    Q Li

    2013-10-01

    Full Text Available Marine bivalves have a set of unique capabilities to adapt to the complicated conditions owing to their habitats, living habits and feeding ways. Meanwhile, marine bivalves can be the biosensors to monitor the quality of the intertidal zones or other habitats. It is interesting for every biologist to find out the mechanisms by which organisms adapt to environmental challenges and the factors limiting their adaptive capacities. The development of biotechnology over the past few decades has provided biologists with a vast repertoire of biosensors that allow testing mRNA expression in response to environmental factors. This minireview is focused on the transcriptomic responses to abiotic and biotic stressors in bivalves and the relative methods to provide new perspectives as well as improve applications for bivalve biomonitoring studies.

  2. On the benthic molluscs of Banco Inglés (Río de la Plata, Uruguay

    Directory of Open Access Journals (Sweden)

    Carranza, A.

    2007-12-01

    Full Text Available We describe the specific richness and community structure of benthic molluscs on a shallow-water sandy bank (Banco Inglés in the Río de la Plata estuary. From a total of 25 macroinvertebrate taxa collected, that included one ophiuroid, one bryozoan, fourcrustaceans and four polychaete species, molluscs were the dominant taxon, with 15 species recorded. These were one species of Polyplacophora, eight Bivalvia and six Gastropoda (one exotic, representing 11families and 11 genera. In terms of mean relative abundance, the molluscan assemblage was dominated by the deposit-feeder bivalve Corbula caribaea, averaging ca. 30% of the individuals of the macroinfauna. The alien species Rapana venosa was noted in two stations, represented by one and four specimens. We used null model analysis to test for nonrandomness in the structure of the molluscan communities of the area. The analysis supported the null hypothesis that co-occurrence patterns could not be distinguished from those that might arise by random processes.

  3. Assessment of Bivalves as potential bioindicator of heavy metal pollution along Ghana's coast using Instrumental Neutron Activation Analysis

    International Nuclear Information System (INIS)

    The assessment of environmental metal pollution along the coast of Ghana was investigated by analysing the heavy and trace metals in the soft body tissue and shells of two abundant bivalve molluses Donax pulchelus, the brown mussel Perna perna and the sediment in which they live at three different sampling locations (Accra, Cape Coast and Axim). Potentially toxic or toxic metals analysed in this study were Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Sc, V, Zn using the analytical technique instrumental Neutron Activation Analysis (INAA) in the quantitative determination of the heavy metals. Marine sediment reference material (Estuarine Sediment SRM 1646a) and Peach leaves SRM 1547 provided the certified reference in the quality assurance control. The concentration found in the potentially toxic heavy metals (As, Cd, Co, Cu, Hg, Ni,and Zn) all recorded lower than the maximum acceptable limits in the bivalve molluscs designated for human consumption, fluctuating between blow detection limit <0.03 to 180.38μ/g. The other elements (Al, Ca, Fe, K, Mg, Mn and Na) recorded a high concentration in both Donax pulchelus and Perna perna (4.54μ/g to 565.13μ/g) in all the sampling location.The minor elements (V and Sc) recorded between 0.05 μ/g to 5.68μ/g. The data on the concentration of the bivalve mollusc also showed lower values compared with other regions of the world. The physicochemical parameters determined were generally supportive of aquatic life providing the necessary conditions. (au)

  4. Voyaging around nacre with the X-ray shuttle: From bio-mineralisation to prosthetics via mollusc phylogeny

    International Nuclear Information System (INIS)

    Research highlights: → Nacre could be a non ancestral form of calcium carbonate in molluscs. → Texture terms as useful links to ancestors in classification. → X-ray diffraction useful for biomineralisation, phylogeny, cladistic and implantology. → Farming conditions do not influence much shell growth. → Electrodeposition of aragonite as future technique for implant coating. - Abstract: Strong textures of mollusc shell layers are utilised to provide phylogenetic information. Aragonitic and calcitic layers are the targets here, inside which nacre layers, but not only, play a specific role. At the light of the texture patterns and a parcimonious approach, nacre appears not as an ancestral form of calcium carbonate in mollusc layers. Also, from texture terms we can propose some links to ancestral fossilised species. The aragonite unit-cell distortions due to macromolecule complex insertions in the microstructures are measured on raw specimens for several aragonite layers of gastropods and bivalves. The textural information is used to provide precise structural determination of the biogenic aragonite. Such information might provide useful lights on the biomineralisation processes in the future, in cladistic approaches. Farming conditions are shown not to influence much shell textures of Helix aspersa aspersa. Closely related species exhibit globally close textures, among which three are good candidates for bone neogeneration and which textures are identical. Electrodeposition of aragonite, with inclusion of molecular extract from shell species, results in nacre-like layers exhibiting structural distortions similar to known inductive layers. X-ray diffraction experiments are shown to provide invaluable insights in testing biomineralisation and phylogenetic hypotheses.

  5. Nivní malakofauna Ploučnice (Severní Čechy The floodplain mollusc fauna of the Ploučnice River (North Bohemia

    Directory of Open Access Journals (Sweden)

    Lucie Juřičková

    2013-04-01

    Full Text Available This paper presents a research of the floodplain mollusc communities of the Ploučnice River (Elbe tributary, North Bohemia, Czech Republic. Altogether, 66 mollusc species (65 species of gastropods, one species of bivalve were recorded in the 35 floodplain forest sites during the research between 2007 and 2011, representing 27% of the total Czech malacofauna. More than a half of all species represents the common forest species (52% of all recorded species with some rare woodland species as Aegopinella nitidula, Daudebardia rufa, Macrogastra ventricosa, Oxychilus depressus, O. glaber and two endangered species Clausilia bidentata and Daudebardia brevipes. Rare wetland species protected by the NATURA system Vertigo angustior and vulnerable V. antivertigo were also found. The occurrence of these rare species (two of them endangered, three vulnerable, and 11 near threatened makes the Ploučnice river alluvium as an important mollusc refugium of prime conservation importance in this fragmented Czech landscape of long-term agricultural land use.

  6. Contamination in sediments, bivalves and sponges of McMurdo Sound, Antarctica

    International Nuclear Information System (INIS)

    This study examined the concentrations of total hydrocarbons (THC), polychlorinated biphenyls (PCB), polyaromatic hydrocarbons (PAH), and trace metals (Cu, Zn, Cd, Pb, Hg and As) in marine sediments off Scott Base (NZ) and compared them with sediments near the highly polluted McMurdo Station (US) as well as less impacted sites including Turtle Rock and Cape Evans. The Antarctic mollusc, Laternula elliptica and three common sponge species were also analysed for trace metals. The mean THC concentration in sediments from Scott Base was 3 fold higher than the pristine site, Turtle Rock, but 10 fold lower than samples from McMurdo Station. McMurdo Station sediments also contained the highest concentrations of PAHs, PCBs and the trace metals, Cu, Zn, Pb, Cd and Hg. Copper was significantly higher in bivalves from McMurdo Station than other sites. Trace metal concentrations in sponges were generally consistent within sites but no spatial patterns were apparent. - Analyses of Antarctic marine sediments, bivalves and sponges revealed strong PAH, PCB and trace metal gradients in McMurdo Sound

  7. Investigating the impact of drilling mud and its major components on bivalve species of Georges bank. Progress report No. 2, February 28, 1979-November 1, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1979-11-01

    Results described in progress report No. 1 indicate that 0.3-1.0 grams of drilling mud/liter of seawater can stress bivalve molluscs and that metallic components of drilling muds are assimilated by these organisms. The results posed questions about the short- and long-term effects of stress on energy stores, reproduction, and metal assimilation; accordingly, this year's research program has focused on these three areas and on a continued chemical characterization of the drilling muds used.

  8. Patterns of DNA Barcode Variation in Canadian Marine Molluscs

    OpenAIRE

    Layton, Kara K. S.; Martel, André L.; Hebert, Paul D. N.

    2014-01-01

    BACKGROUND: Molluscs are the most diverse marine phylum and this high diversity has resulted in considerable taxonomic problems. Because the number of species in Canadian oceans remains uncertain, there is a need to incorporate molecular methods into species identifications. A 648 base pair segment of the cytochrome c oxidase subunit I gene has proven useful for the identification and discovery of species in many animal lineages. While the utility of DNA barcoding in molluscs has been demonst...

  9. Repamo network : a surveillance tool for mollusc health

    OpenAIRE

    Garcia, Celine; ARZUL, Isabelle; Chollet, Bruno; Francois, Cyrille; Joly, Jean-pierre; Miossec, Laurence; Robert, Maeva

    2005-01-01

    At the present time losses due to diseases are one of main factors limiting the aquaculture development. Unceasing increase of exchanges between different countries favours the risk of introduction and propagation of new pathogen agents. At the beginning of the 90's the European Union laid the surveillance of mollusc health inside each Member State in order to protect the safety of exchanges. Indeed few measures are available to protect molluscs from diseases. Only the prophylactic approach i...

  10. The Ghost in the Shell : Local and Remote Forcing of a Coastal Bivalve Inhabiting the Humboldt Current System

    Science.gov (United States)

    Gosselin, M.

    2014-12-01

    The external skeleton of mollusc bivalves, the shell, can furnish a recording of the environmental changes to which the organisms and population are exposed during their lives. The bivalve's growth is subjected to the thermocline variability; which itself is affected by environmental and climatic events. A highly variable environment such as the Humboldt current system (HCS) requires tools capable of recording its variations over a wide range of periodicities. Upwelling, Coastal trapped waves (CTWs), El Niño Southern Oscillation, and Pacific decadal oscillation events contribute to this environmental and climatic variability. The thermocline depth is modified by these different events at their own time-scales (respectively, daily to weekly, intraseasonally, interseasonally to interannually, and on a decadal scale). The thermocline variation translates into changes in Sea surface temperature (SST) and in the qualitative and quantitative productivity of phytoplankton. These two environmental factors are critical to bivalve growth.The sclerochronological (increment width) and sclerochemical (δ18O and δ13C) study consisted on the analysis of the Chilean bivalve Eurhomalea rufa, collected in 2005, as a recorder of the environmental HCS variability. The calibration step identified daily, monthly, and annual marks in the growth patterns of E. rufa. The results confirmed that the thermocline variability mainly drives the bivalve's activity and led to the establishment of a paleotemperature equation. Moreover, periodogram and wavelet analyses exposed the respective impacts of each environmental event from daily to interannual periodicities. In particular, the growth pattern of E. rufa follows SST variability at an intraseasonal periodicity (~ 60 days) which is remotely induced by CTWs. CTWs are generated by Kelvin oceanic waves, which are formed primarily by eastward equatorial Pacific winds (e.g. Shaffer et al. 1997; Montecino and Lange 2009).Sclerochronological studies

  11. Testing cosmic dose rate models for ESR: Dating corals and molluscs on San Salvador, Bahamas

    International Nuclear Information System (INIS)

    Sealevel curves are best developed on tectonically stable coastlines, like San Salvador, where eolianites preserve transgressive and regressive phases associated with Quaternary high seastands, while reef facies mark the highstands. At 11 locations around San Salvador, terrestrial molluscs (Cerion) from the eolianites, lagoonal bivalves (Codakia), and corals from the highstand deposits were dated by ESR. Volumetrically averaged sedimentary dose rates were calculated from sedimentary geochemistry and time-averaged cosmic dose rates from each sample's current and past geologic contexts. Rice Bay Formation corals dated at 3.9 ± 0.3 to 7.1 ± 0.4 ka (OIS 1). Minimum ages for the Cockburn Town Member's regressive phase ranged from 49 ± 6 to 75 ± 8 ka, correlating with OIS 3-4. Codakia dates showed that an OIS 5a sealevel approached modern levels at 91-78 ka. In situ corals from the Cockburn Town Reef averaged from 127 ± 6 to 138 ± 10 ka, correlating well with OIS 5e. Ages from the Reef's rubble zones hint that some coral reefs grew as early as OIS 7, but were likely reworked during OIS 5. San Salvador preserves deposits from three mid to late Quaternary highstands above, and as many as three that closely approach, modern sealevel.

  12. Testing cosmic dose rate models for ESR: Dating corals and molluscs on San Salvador, Bahamas

    Energy Technology Data Exchange (ETDEWEB)

    Deely, A.E. [RFK Science Research Institute, Glenwood Landing, NY, 11547-0866 (United States); Blackwell, B.A.B., E-mail: bonnie.a.b.blackwell@williams.edu [RFK Science Research Institute, Glenwood Landing, NY, 11547-0866 (United States); Dept. of Chemistry, Williams College, Williamstown MA, 01267-2692 (United States); Mylroie, J.E. [Dept. of Geosciences, Mississippi State University, MS, 39762-5448 (United States); Carew, J.L. [Dept. of Geology and Environmental Geosciences, College of Charleston, Charleston, SC 29424 (United States); Blickstein, J.I.B. [RFK Science Research Institute, Glenwood Landing, NY, 11547-0866 (United States); Skinner, A.R. [RFK Science Research Institute, Glenwood Landing, NY, 11547-0866 (United States); Dept. of Chemistry, Williams College, Williamstown MA, 01267-2692 (United States)

    2011-09-15

    Sealevel curves are best developed on tectonically stable coastlines, like San Salvador, where eolianites preserve transgressive and regressive phases associated with Quaternary high seastands, while reef facies mark the highstands. At 11 locations around San Salvador, terrestrial molluscs (Cerion) from the eolianites, lagoonal bivalves (Codakia), and corals from the highstand deposits were dated by ESR. Volumetrically averaged sedimentary dose rates were calculated from sedimentary geochemistry and time-averaged cosmic dose rates from each sample's current and past geologic contexts. Rice Bay Formation corals dated at 3.9 {+-} 0.3 to 7.1 {+-} 0.4 ka (OIS 1). Minimum ages for the Cockburn Town Member's regressive phase ranged from 49 {+-} 6 to 75 {+-} 8 ka, correlating with OIS 3-4. Codakia dates showed that an OIS 5a sealevel approached modern levels at 91-78 ka. In situ corals from the Cockburn Town Reef averaged from 127 {+-} 6 to 138 {+-} 10 ka, correlating well with OIS 5e. Ages from the Reef's rubble zones hint that some coral reefs grew as early as OIS 7, but were likely reworked during OIS 5. San Salvador preserves deposits from three mid to late Quaternary highstands above, and as many as three that closely approach, modern sealevel.

  13. Effects of ocean acidification on immune responses of the Pacific oyster Crassostrea gigas.

    Science.gov (United States)

    Wang, Qing; Cao, Ruiwen; Ning, Xuanxuan; You, Liping; Mu, Changkao; Wang, Chunlin; Wei, Lei; Cong, Ming; Wu, Huifeng; Zhao, Jianmin

    2016-02-01

    Ocean acidification (OA), caused by anthropogenic CO2emissions, has been proposed as one of the greatest threats in marine ecosystems. A growing body of evidence shows that ocean acidification can impact development, survival, growth and physiology of marine calcifiers. In this study, the immune responses of the Pacific oyster Crassostrea gigas were investigated after elevated pCO2 exposure for 28 days. The results demonstrated that OA caused an increase of apoptosis and reactive oxygen species (ROS) production in hemocytes. Moreover, elevated pCO2 had an inhibitory effect on some antioxidant enzyme activities and decreased the GSH level in digestive gland. However, the mRNA expression pattern of several immune related genes varied depending on the exposure time and tissues. After exposure to pCO2 at ∼2000 ppm for 28 days, the mRNA expressions of almost all tested genes were significantly suppressed in gills and stimulated in hemocytes. Above all, our study demonstrated that elevated pCO2 have a significant impact on the immune systems of the Pacific oyster, which may constitute as a potential threat to increased susceptibility of bivalves to diseases. PMID:26706224

  14. Characterization of GnRH-related peptides from the Pacific oyster Crassostrea gigas.

    Science.gov (United States)

    Bigot, Laetitia; Zatylny-Gaudin, Céline; Rodet, Franck; Bernay, Benoit; Boudry, Pierre; Favrel, Pascal

    2012-04-01

    Gonadotropin-releasing hormone (GnRH), a key neuropeptide regulating reproduction in vertebrates has now been characterized in a number of non-vertebrate species. Despite the demonstration of its ancestral origin, the structure and the function of this family of peptides remain poorly known in species as distant as lophotrochozoans. In this study, two GnRH-related peptides (Cg-GnRH-a and CgGnRH-G) were characterized by mass spectrometry from extracts of the visceral ganglia of the Pacific oyster Crassostrea gigas. These peptides showed a high degree of sequence identity with GnRHs of other mollusks and annelids and to a lesser extent with those of vertebrates or with AKH and corazonins of insects. Both the mature peptides and the transcript encoding the precursor protein were exclusively expressed in the visceral ganglia. Significant differences in transcriptional activity of Cg-GnRH encoding gene were recorded in the ganglia along the reproductive cycle and according to trophic conditions with a higher level in fed animals compared to starved animals. This suggests the involvement of Cg-GnRHs as synchronizers of nutritional status with energy requirements during reproduction in oyster. Evidence for a role of Cg-GnRHs as neuroregulators and as neuroendocrine factors in bivalve is discussed. PMID:22306476

  15. Drilling predation on molluscs in the northern Adriatic Sea: Spatial variability and temporal trends over the last millennia

    Science.gov (United States)

    Dengg, Markus; Wurzer, Sandra; Gallmetzer, Ivo; Haselmair, Alexandra; Zuschin, Martin

    2016-04-01

    Competition and predation are essential ecological factors influencing biodiversity. In a palaeontological context, the rate of predatory interactions between animal species is difficult to reconstruct because traces of predation are rarely incorporated into the fossil record. In the marine environment, the calcareous shells of molluscs, however, have good, long-time preservation potential, and predation in this group is often exerted by carnivorous gastropods that drill holes into mollusc shells. The prey's perforated shells remain in the sediment and can be used to study rates and intensities of predatory interactions in past marine molluscan communities. Differences in drilling frequencies along a sediment core not only reflect changes in local species richness and predation pressure, but may also mirror ecosystem changes through space and time. This makes the analysis of drilling predation an important tool when investigating the historical ecology of marine habitats. We used 1.5-m-long sediment cores from seven shelf locations spread throughout the northern Adriatic Sea basin to investigate regional and down-core variations in drilling frequencies. In total, about 54,000 bivalve and 40,000 gastropod shells were analysed to determine the following parameters: 1) overall drill frequency (DF), the proportion of shells drilled by predators; 2) edge drill frequency (EDF, only in bivalve shells), the proportion of shells with drilling traces at the shell edge; 3) multiple drill frequency (MDF), the percentage of individuals with more than one drill hole, 4) incomplete drill frequency (IDF), the percentage of shells unsuccessfully drilled; 5) prey effectiveness (PE), the proportion of individuals resisting the predator's attacks. Total drill frequency across all cores is 18% for bivalves and 13% for gastropods, but there are marked regional differences, with minima in the Po Delta (5%) and maxima in Panzano Bay (24%). Edge-drilled shells and multiple drill holes on

  16. Sub-chronic exposure to fluoxetine in juvenile oysters (Crassostrea gigas): uptake and biological effects.

    Science.gov (United States)

    Di Poi, Carole; Evariste, Lauris; Séguin, Alexis; Mottier, Antoine; Pedelucq, Julie; Lebel, Jean-Marc; Serpentini, Antoine; Budzinski, Hélène; Costil, Katherine

    2016-03-01

    The bioconcentration potential of fluoxetine (FLX) and its biological effects were investigated in juvenile Pacific oyster exposed for 28 days to environmentally relevant concentrations of FLX (1 ng L(-1), 100 ng L(-1) and up to 10 μg L(-1)). FLX bioaccumulated in oyster flesh resulting in 28-day bioconcentration factors greater than 2,000 and 10,000 by referring to wet and dry weights, respectively. Nevertheless, FLX did not induce oyster mortality, delayed gametogenesis, or lead to adverse histopathological alterations. At the two highest concentrations, despite non-optimal trophic conditions, FLX stimulated shell growth but only in a transient manner, suggesting a role of serotonin in the regulation of feeding and metabolism in bivalves. Those high concentrations seemed to drive bell-shaped responses of catalase and glutathione S-transferase activities throughout the exposure period, which may indicate the activation of antioxidant enzyme synthesis and then an enhanced catabolic rate or direct inhibition of those enzymes. However, no clear oxidative stress was detected because no strong differences in thiobarbituric acid-reactive substance (TBARS) content (i.e. lipid peroxidation) were observed between oyster groups, suggesting that cellular defence mechanisms were effective. These results demonstrate the importance of considering additional biomarkers of oxidative stress to obtain a comprehensive overview of the FLX-induced changes in marine bivalves exposed under realistic conditions. Considering the battery of biomarkers used, FLX appears to induce little or no effects on oyster physiology even at a concentration of 10 μg L(-1). These results do not confirm the lowest observed effect concentration (LOEC) values reported by some authors in other mollusc species. PMID:25315935

  17. Oxidative stress and bivalves: a proteomic approach

    Directory of Open Access Journals (Sweden)

    B McDonagh

    2008-09-01

    Full Text Available Bivalves are of major importance in aquatic ecology, aquaculture, are widely used as sentinel species in environmental toxicology and show remarkable plasticity to molecular oxygen. Excess reactive oxygen species (ROS arising from molecular oxygen can cause oxidative stress and this is also a consequence of exposure to many common environmental pollutants. Indices of oxidative stress have therefore found favor as biomarkers of exposure and effect in environmental toxicology. However, there is a growing body of literature on the use of discovery-led proteomics methods to detect oxidative stress in bivalves. This is because proteins absorb up to 70 % of ROS leading to complication of the proteome. This article explores the background to these developments and assesses the practice and future potential of proteomics in the study of oxidative stress in bivalves.

  18. Passive biomonitoring study and effect biomarker in oysters Crassostrea brasiliana (Lamark, 1819. Mollusca, Bivalvia) in Santos and Cananeia Estuaries in Sao Paulo State, Brazil

    International Nuclear Information System (INIS)

    This study assessed the exposure and effects of trace elements in sentinel organisms, using the bivalve Crassostrea brasiliana in two estuarine areas in Sao Paulo State, Brazil: Santos Estuary and Cananeia Estuary, site of oyster farms, which was used as reference site. Oysters were evaluated for bioaccumulation of As, Co, Cr, Fe, Se and Zn by INAA and Cd, Pb and Hg by AAS. Effect biomarker was assessed by evaluation of lysosomal membrane stability. In the study of bioaccumulation of trace elements it was verified that Santos Channel presented the largest concentrations of elements studied in most cases. From the study of the cellular biomarker, it was verified that Santos Channel and winter showed higher stress to organisms in the present study. (author)

  19. An exceptionally preserved vermiform mollusc from the Silurian of England.

    Science.gov (United States)

    Sutton, M D; Briggs, D E; Siveter, D J; Siveter, D J

    2001-03-22

    Studies of the origin and radiation of the molluscs have yet to resolve many issues regarding their nearest relatives, phylogeny and ancestral characters. The Polyplacophora (chitons) and the Aplacophora are widely interpreted as the most primitive extant molluscs, but Lower Palaeozoic fossils of the former lack soft parts, and the latter were hitherto unrecognized as fossils. The Herefordshire Lagerstätte is a Silurian (about 425 Myr bp) deposit that preserves a marine biota in remarkable three-dimensional detail. The external surface of even non-biomineralized cuticle was preserved by entombment in volcanic ash, subsequent incorporation into concretions, and infilling of the fossils with sparry calcite. Here we describe, from this deposit, a complete vermiform mollusc, which we interpret as a plated aplacophoran. Serial grinding at intervals of tens of micrometres, combined with computer-based reconstruction methods, renders the fossils in the round. PMID:11260711

  20. Resolving the evolutionary relationships of molluscs with phylogenomic tools.

    Science.gov (United States)

    Smith, Stephen A; Wilson, Nerida G; Goetz, Freya E; Feehery, Caitlin; Andrade, Sónia C S; Rouse, Greg W; Giribet, Gonzalo; Dunn, Casey W

    2011-12-15

    Molluscs (snails, octopuses, clams and their relatives) have a great disparity of body plans and, among the animals, only arthropods surpass them in species number. This diversity has made Mollusca one of the best-studied groups of animals, yet their evolutionary relationships remain poorly resolved. Open questions have important implications for the origin of Mollusca and for morphological evolution within the group. These questions include whether the shell-less, vermiform aplacophoran molluscs diverged before the origin of the shelled molluscs (Conchifera) or lost their shells secondarily. Monoplacophorans were not included in molecular studies until recently, when it was proposed that they constitute a clade named Serialia together with Polyplacophora (chitons), reflecting the serial repetition of body organs in both groups. Attempts to understand the early evolution of molluscs become even more complex when considering the large diversity of Cambrian fossils. These can have multiple dorsal shell plates and sclerites or can be shell-less but with a typical molluscan radula and serially repeated gills. To better resolve the relationships among molluscs, we generated transcriptome data for 15 species that, in combination with existing data, represent for the first time all major molluscan groups. We analysed multiple data sets containing up to 216,402 sites and 1,185 gene regions using multiple models and methods. Our results support the clade Aculifera, containing the three molluscan groups with spicules but without true shells, and they support the monophyly of Conchifera. Monoplacophora is not the sister group to other Conchifera but to Cephalopoda. Strong support is found for a clade that comprises Scaphopoda (tusk shells), Gastropoda and Bivalvia, with most analyses placing Scaphopoda and Gastropoda as sister groups. This well-resolved tree will constitute a framework for further studies of mollusc evolution, development and anatomy. PMID:22031330

  1. Identification of reproduction-specific genes associated with maturation and estrogen exposure in a marine bivalve Mytilus edulis.

    Directory of Open Access Journals (Sweden)

    Corina M Ciocan

    Full Text Available BACKGROUND: While it is established that vertebrate-like steroids, particularly estrogens (estradiol, estrone and androgens (testosterone, are present in various tissues of molluscs, it is still unclear what role these play in reproductive endocrinology in such organisms. This is despite the significant commercial shellfishery interest in several bivalve species and their decline. METHODOLOGY/PRINCIPAL FINDINGS: Using suppression subtraction hybridisation of mussel gonad samples at two stages (early and mature of gametogenesis and (in parallel following controlled laboratory estrogen exposure, we isolate several differentially regulated genes including testis-specific kinases, vitelline lysin and envelope sequences. CONCLUSIONS: The differentially expressed mRNAs isolated provide evidence that mussels may be impacted by exogenous estrogen exposure.

  2. Stanols as a tool to track the origin of microbial contamination of oysters, Crassostrea gigas, in shellfish areas.

    Science.gov (United States)

    Harrault, Loïc; Jardé, Emilie; Jeanneau, Laurent; Petitjean, Patrice

    2013-04-01

    Runoff of cattle manures (cows, pigs, sheeps) or discharge of effluent from wastewater treatment plants (WWTP) into aquatic ecosystems can lead to microbiological contamination of waters and living organisms. In coastal ecosystems and particularly in shellfish harvesting areas, the presence of pathogen microorganisms in waters induces fecal contamination of filter feeding bivalves (oysters, mussels, scallops…), therefore leading to human health risks associated to the consumption of these contaminated organisms. Watershed management plans that aim at limiting these risks require the development of tools able to identify fecal contamination sources. The fecal indicator bacteria used in the regulations to determine fecal contamination are not source specific since they are found in the feces of most warm-blooded animals. Thus, microbiological biomarkers have been developed in association with chemical biomarkers as Microbial Source Tracking (MST) methods. Fecal stanols, by-products of sterols obtained by human and animal microbial gut flora, are found in considerable amounts in feces with different relative proportions depending on their animal or human source. Recently, in association with microbiological biomarkers, the stanol fingerprint of contaminated waters has been successfully used to determine the main source of fecal contamination (cow, pig or human sources) in rural watersheds (Brittany, France). Up to now, the use of the stanol fingerprint to track the fecal contamination in shellfish tissues, especially bivalves, has been limited to the analysis of coprostanol, a stanol commonly associated to human contamination. Therefore, whether the stanol fingerprint can be used as a MST method in bivalves or not is still unknown. The first aim of this study was to compare several organic extraction procedures of stanols in the oyster Crassostrea gigas to determine a reliable method for stanol fingerprint analysis in bivalves. Solvent extraction and purification

  3. Morphometric method for the bivalve molluscs shells with regard to linear dimension anisometry (using Mediterranean mussel as an example)

    OpenAIRE

    Polupanov, V.N.; Misar, M.A.

    2015-01-01

    Рассматривается метод определения онтогенетической изменчивости формы двустворок, исходя из простой геометрической модели, учитывающей взаимосвязь линейных размеров, объема и массы. Предлагаемый метод основан на двух способах мультипликативного разложения размеров растущей раковины: первое разложение позволяет определить пропорции линейных размеров (изометрию), второе – изменение пропорций (анизометрию). Для нелинейного разложения (учета анизометрии) применяются степенные функц...

  4. Application of rapid test kits for the determination of paralytic shellfish poisoning (PSP) toxins in bivalve molluscs from Great Britain.

    Science.gov (United States)

    Harrison, Keith; Johnson, Sarah; Turner, Andrew D

    2016-09-01

    Six different commercial rapid screening assays for Paralytic Shellfish Poisoning toxins were assessed with the analysis of shellfish samples from GB. The performance of each kit was assessed through comparison with the current regulatory HPLC method. Samples assessed consisted of a wide variety of shellfish species of importance to the shellfish industry in GB. These had been sourced over a number of years and with a wide variety of geographical origins. One lateral flow immunoassay was found to provide a quick qualitative assessment of PSP toxicity, with a low proportion of false negative results for PSP-positive samples, but with higher numbers of false positives. The performance of the five quantitative ELISA assays varied considerably, with two demonstrating an inappropriate linear range, with others either over-estimating or under-estimating toxicity. One ELISA from R-Biopharm was found to show a good correlation with the HPLC toxicity results. All ELISAs, however, returned some false negative results, most notably for samples containing high proportions of toxins with low cross reactivity to saxitoxin such as GTX1&4. Whilst the lateral flow assays on the market are of particular use to Food Business Operators for end product testing, further work is required in parallel with instrumental testing methods using a larger number of samples to assess the reliability and accuracy of these kits over the long term. PMID:27373993

  5. Mollusc reproductive toxicity tests - Development and validation of test guidelines

    DEFF Research Database (Denmark)

    Ducrot, Virginie; Holbech, Henrik; Kinnberg, Karin Lund

    ). Cumulated fecundity per individual over the test period was SETAC 6th World Congress/SETAC Europe 22nd Annual Meeting 223 the main test endpoint. Tested animals came from a single laboratory culture (i.e. the University of Frankfurt for P. antipodarum and INRA for L. stagnalis). Snails were acclimated in...... experimental conditions and test procedures is required before the SOPs are ready to be proposed as OECD test guidelines.......The Organisation for Economic Cooperation and Development is promoting the development and validation of mollusc toxicity tests within its test guidelines programme, eventually aiming for the standardization of mollusc apical toxicity tests. Through collaborative work between academia, industry and...

  6. Bivalve grazing can shape phytoplankton communities

    Science.gov (United States)

    Lucas, Lisa; Cloern, James E.; Thompson, Janet K.; Stacey, Mark T.; Koseff, Jeffrey K.

    2016-01-01

    The ability of bivalve filter feeders to limit phytoplankton biomass in shallow waters is well-documented, but the role of bivalves in shaping phytoplankton communities is not. The coupled effect of bivalve grazing at the sediment-water interface and sinking of phytoplankton cells to that bottom filtration zone could influence the relative biomass of sinking (diatoms) and non-sinking phytoplankton. Simulations with a pseudo-2D numerical model showed that benthic filter feeding can interact with sinking to alter diatom:non-diatom ratios. Cases with the smallest proportion of diatom biomass were those with the fastest sinking speeds and strongest bivalve grazing rates. Hydrodynamics modulated the coupled sinking-grazing influence on phytoplankton communities. For example, in simulations with persistent stratification, the non-sinking forms accumulated in the surface layer away from bottom grazers while the sinking forms dropped out of the surface layer toward bottom grazers. Tidal-scale stratification also influenced vertical gradients of the two groups in opposite ways. The model was applied to Suisun Bay, a low-salinity habitat of the San Francisco Bay system that was transformed by the introduction of the exotic clam Potamocorbula amurensis. Simulation results for this Bay were similar to (but more muted than) those for generic habitats, indicating that P. amurensis grazing could have caused a disproportionate loss of diatoms after its introduction. Our model simulations suggest bivalve grazing affects both phytoplankton biomass and community composition in shallow waters. We view these results as hypotheses to be tested with experiments and more complex modeling approaches.

  7. Evolution and functional analysis of the Pif97 gene of the Pacific oyster Crassostrea gigas

    Directory of Open Access Journals (Sweden)

    Xiaotong WANG, Xiaorui SONG, Tong WANG, Qihui ZHU, Guoying MIAO, Yuanxin CHEN, Xiaodong FANG, Huayong QUE, Li LI, Guofan ZHANG

    2013-02-01

    Full Text Available Mollusc shell matrix proteins (SMPs are important functional components embedded in the shell and play a role in shell formation. A SMP (Pif177 was identified previously from the nacreous layer of the Japanese pearl oyster Pinctada fucata, and its cleavage products (named pfPif97 and pfPif80 proteins were found to bind to the chitin framework and induce aragonite crystal formation and orient the c axis. In this study, a homologue of pfPif177 was cloned from the mantle of the Pacific oyster Crassostrea gigas, containing the homologue of pfPif97 only and not pfPif80. This finding hints at the large divergence in gene structure between the two species. This homologue (cgPif97 shares characteristics with pfPif97, and suggests that the biological functions of these two proteins may be similar. The expression pattern of cgPif97 in different tissues and development stages indicates that it may play an important role in shell formation of the adult oyster. The morphology of the inner shell surface was affected by injected siRNA of cgPif97 and the calcite laths of the shell became thinner and narrower when the siRNA dose increased, suggesting that the cgPif97 gene plays an important role in calcite shell formation in C. gigas. In conclusion, we found evidence that the Pif177 gene evolved very fast but still retains a similar function among species [Current Zoology 59 (1: 109–115, 2013].

  8. Evolution and functional analysis of the Pif97 gene of the Pacific oyster Crassostrea gigas

    Institute of Scientific and Technical Information of China (English)

    Xiaotong WANG; Xiaorui SONG; Tong WANG; Qihui ZHU; Guoying MIAO; Yuanxin CHEN; Xiaodong FANG

    2013-01-01

    Mollusc shell matrix proteins (SMPs) are important functional components embedded in the shell and play a role in shell formation.A SMP (Pif177) was identified previously from the nacreous layer of the Japanese pearl oyster Pinctada fucata,and its cleavage products (named pfPif97 and pfPif80 proteins) were found to bind to the chitin framework and induce aragonite crystal formation and orient the c axis.In this study,a homologue ofpfPifl77 was cloned from the mantle of the Pacific oyster Crassostrea gigas,containing the homologue of pfPif97 only and not pfPif80.This finding hints at the large divergence in gene structure between the two species.This homologue (cgPif97) shares characteristics with pfPif97,and suggests that the biological functions of these two proteins may be similar.The expression pattern of cgPif97 in different tissues and development stages indicates that it may play an important role in shell formation of the adult oyster.The morphology of the inner shell surface was affected by injected siRNA of cgPif97 and the calcite laths of the shell became thinner and narrower when the siRNA dose increased,suggesting that the cgPif97 gene plays an important role in calcite shell formation in C.gigas.In conclusion,we found evidence that the Pif177 gene evolved very fast but still retains a similar function among species [Current Zoology 59 (1):109-115,2013].

  9. Bioaccumulation efficiency, tissue distribution, and environmental occurrence of hepatitis E virus in bivalve shellfish from France.

    Science.gov (United States)

    Grodzki, Marco; Schaeffer, Julien; Piquet, Jean-Côme; Le Saux, Jean-Claude; Chevé, Julien; Ollivier, Joanna; Le Pendu, Jacques; Le Guyader, Françoise S

    2014-07-01

    Hepatitis E virus (HEV), an enteric pathogen of both humans and animals, is excreted by infected individuals and is therefore present in wastewaters and coastal waters. As bivalve molluscan shellfish are known to concentrate viral particles during the process of filter feeding, they may accumulate this virus. The bioaccumulation efficiencies of oysters (Crassostrea gigas), flat oysters (Ostrea edulis), mussels (Mytilus edulis), and clams (Ruditapes philippinarum) were compared at different time points during the year. Tissue distribution analysis showed that most of the viruses were concentrated in the digestive tissues of the four species. Mussels and clams were found to be more sensitive to sporadic contamination events, as demonstrated by rapid bioaccumulation in less than 1 h compared to species of oysters. For oysters, concentrations increased during the 24-h bioaccumulation period. Additionally, to evaluate environmental occurrence of HEV in shellfish, an environmental investigation was undertaken at sites potentially impacted by pigs, wild boars, and human waste. Of the 286 samples collected, none were contaminated with hepatitis E virus, despite evidence that this virus is circulating in some French areas. It is possible that the number of hepatitis E viral particles discharged into the environment is too low to detect or that the virus may have a very short period of persistence in pig manure and human waste. PMID:24795382

  10. Shell Extracts from the Marine Bivalve Pecten maximus Regulate the Synthesis of Extracellular Matrix in Primary Cultured Human Skin Fibroblasts

    Science.gov (United States)

    Latire, Thomas; Legendre, Florence; Bigot, Nicolas; Carduner, Ludovic; Kellouche, Sabrina; Bouyoucef, Mouloud; Carreiras, Franck; Marin, Frédéric; Lebel, Jean-Marc; Galéra, Philippe; Serpentini, Antoine

    2014-01-01

    Mollusc shells are composed of more than 95% calcium carbonate and less than 5% of an organic matrix consisting mostly of proteins, glycoproteins and polysaccharides. Previous studies have elucidated the biological activities of the shell matrices from bivalve molluscs on skin, especially on the expression of the extracellular matrix components of fibroblasts. In this work, we have investigated the potential biological activities of shell matrix components extracted from the shell of the scallop Pecten maximus on human fibroblasts in primary culture. Firstly, we demonstrated that shell matrix components had different effects on general cellular activities. Secondly, we have shown that the shell matrix components stimulate the synthesis of type I and III collagens, as well as that of sulphated GAGs. The increased expression of type I collagen is likely mediated by the recruitment of transactivating factors (Sp1, Sp3 and human c-Krox) in the −112/−61 bp COL1A1 promoter region. Finally, contrarily to what was obtained in previous works, we demonstrated that the scallop shell extracts have only a small effect on cell migration during in vitro wound tests and have no effect on cell proliferation. Thus, our research emphasizes the potential use of shell matrix of Pecten maximus for dermo-cosmetic applications. PMID:24949635

  11. Cloning and characterization of the follistatin gene from Crassostrea angulata and its expression during the reproductive cycle.

    Science.gov (United States)

    Ni, Jianbin; Zeng, Zhen; Han, Guodong; Huang, Heqing; Ke, Caihuan

    2012-10-01

    Follistatin is an activin-binding protein that prevents activin from binding to its receptor and neutralizes its activity. Follistatin plays a key role in regulating folliculogenesis and the development of ovary. However, limited information on follistatin genes from molluscs is available until now. By using Race, real-time PCR, in situ hybridization and in silico analysis, a full-length cDNA of follistatin of the Portuguese oyster Crassostrea angulata was acquired. The full-length (1297 bp) cDNA of Ca-follistatin encodes a peptide of 241 amino acids. The similarity of its deduced amino acid sequence to these of other invertebrate species was about 60%. Ca-follistatin mRNA transcript was most abundantly expressed in ovary (preproductive cycle of female oyster (initiation stage, maturation stage, ripeness stage and partially spent stage), the expression of Ca-follistatin in the ovary continuously increased from initiation to ripeness stages attaining its highest value (poyster in the testis maintained a relatively stable low level during the first three stages, and also noticeably decreased thereafter (poysters by autocrine signaling. PMID:22771889

  12. Ostreid herpesvirus 1 detection and relationship with Crassostrea gigas spat mortality in France between 1998 and 2006

    Directory of Open Access Journals (Sweden)

    Garcia Céline

    2011-06-01

    Full Text Available Abstract Since its molecular characterisation, Ostreid herpesvirus 1 (OsHV-1 has been regularly detected in Crassostrea gigas in France. Although its pathogenicity was demonstrated on larval stages, its involvement during mortality outbreaks at the juvenile stage was highly suspected but not evidenced. To investigate mortality outbreaks, the French National Network for Surveillance and Monitoring of Mollusc Health (REPAMO carried out two surveys in juvenile C. gigas. The first survey lasted from 1998 to 2006 and was an epidemiological inquiry occurring when oyster farmers reported mortality outbreaks. The second survey, a longitudinal one, was set up in 1998 to complete the network observations on OsHV-1. Data analysis showed a specific pattern of mortality outbreaks associated with OsHV-1 detection. Ostreid herpesvirus 1 detection mainly appeared during the summer, suggesting the influence of the seawater temperature on its occurrence. It mostly presented a patchy distribution in the field in contrast to the nursery. Significant relationship between OsHV-1 detection and spat mortality was found, preferentially in sheltered and closed environments. The longitudinal survey confirmed most of the network observations. Although subsequent works particularly epidemiological surveys would be useful to confirm the causal link between the detection of OsHV-1 and the mortality outbreaks in juvenile C. gigas, the role of OsHV-1 in oyster mortality is progressing.

  13. Shell biofilm-associated nitrous oxide production in marine molluscs

    DEFF Research Database (Denmark)

    Heisterkamp, Ines M.; Schramm, Andreas; Larsen, Lone H.; Svenningsen, Nanna B.; Lavik, Gaute; de Beer, Dirk; Stief, Peter

    2013-01-01

    Emission of the greenhouse gas nitrous oxide (N2O) from freshwater and terrestrial invertebrates has exclusively been ascribed to N2O production by ingested denitrifying bacteria in the anoxic gut of the animals. Our study of marine molluscs now shows that also microbial biofilms on shell surfaces...

  14. Mollusc evolution: seven shells on the sea shore.

    Science.gov (United States)

    Telford, Maximilian J

    2013-11-01

    Recent phylogenies unite two seemingly very different groups of mollusc: the Polyplacophora with multiple shells and the shell-less Aplacophora. The finding of seven muscle rows in larvae of both classes suggests that polyplacophoran-like shell rows have been lost in adult Aplacophora. PMID:24200320

  15. Static tank depuration and chronic short-term experimental contamination of Eastern oysters (Crassostrea virginica) with Giardia duodenalis cysts.

    Science.gov (United States)

    Willis, Jessica E; McClure, J T; McClure, Carol; Spears, Jonathan; Davidson, Jeff; Greenwood, Spencer J

    2015-01-01

    Cysts of the protozoan parasite Giardia have been detected in many bivalve shellfish species worldwide. The detection of zoonotic Giardia duodenalis assemblages A and B is of public health concern, yet there is limited data available demonstrating the bioaccumulation and elimination of Giardia cysts in bivalve shellfish. This study quantified G. duodenalis cysts that were filtered and retained by oysters (Crassostrea virginica) over a one week chronic exposure period, or 24 hour exposure followed by a 6 day depuration period, using static tank systems containing 10 L of 29 ppt water inoculated with 1000 or 10,000 cysts. Under chronic exposure, each oyster retained a mean of 13.4 and 87.4 cysts during the first 24h of exposure at low and high doses, respectively, and the cysts bioaccumulated at a rate of 1.2 and 6.8 cysts/oyster/day, respectively, for the remaining duration of the trials. In acute exposure trials, oysters retained 13.8 cysts or 78.9 cysts at low and high doses, respectively, during the initial 24 hour exposure and naturally depurated cysts at a rate of -0.92 cysts/oyster/day and -2.2 cysts/oyster/day, respectively, after transfer. Although most G. duodenalis cysts were eliminated within the first 24h via pseudofeces and feces, detection of some cysts in the fecal material on day 7 of acute exposure trials was indicative of cysts which passed through the digestive tract and released in feces. Only 48-53% of the initial tank inocula were recovered and may indicate that some cysts were selectively filtered by oysters but degraded through digestion. PMID:25305439

  16. Mitochondrial activity, hemocyte parameters and lipid composition modulation by dietary conditioning in the Pacific oyster Crassostrea gigas.

    Science.gov (United States)

    Dudognon, Tony; Lambert, Christophe; Quere, Claudie; Auffret, Michel; Soudant, Philippe; Kraffe, Edouard

    2014-04-01

    Several parameters can affect membrane lipid composition in bivalves, including diet. Although two fatty acids (FA) 22:6n-3 and 20:5n-3 are essential membrane components, they are sparingly synthesized by bivalves and must be obtained from their diet. Here, effects of dietary modifications of membrane lipid composition were studied at both cellular and subcellular levels in the oyster Crassostrea gigas. To this end, we compared oysters fed two monoalgal diets that differed markedly in their FA composition and a mix of both. As expected, algae impacted phospholipids, in particular 22:6n-3 and 20:5n-3, reflecting differences of dietary microalgae FA composition. Meantime, total saturated FA, total monounsaturated FA, total polyunsaturated FA and total non-methylene-interrupted FA varied little and phospholipid class composition was only slightly affected by diets. Measures made in hemocytes indicated that only mitochondrial membrane potential was affected by diets. Total ROS production as well as mitochondrial superoxide production did not differ with diet. There was no difference in phosphorylating (state 3) and non-phosphorylating (state 4) rates of oxygen consumption rates or in cytochrome c oxidase activity of mitochondria isolated from gills between the three diets. Similarly, neither cytochromes a, b, c or c1 content nor citrate synthase activities were changed, suggesting that number and morphology of mitochondria were not affected by dietary treatment. These results suggest that oysters could possess high homeostatic capabilities, at both cellular and subcellular levels, to minimize the effect of dietary FA and related membrane lipid FA modifications on mitochondrial functions. These capabilities could be a means to face variations in diet composition in their natural environment and to preserve important oyster physiological functions such as growth and reproduction. PMID:24441864

  17. Exposure to the toxic dinoflagellate Alexandrium catenella modulates juvenile oyster Crassostrea gigas hemocyte variables subjected to different biotic conditions.

    Science.gov (United States)

    Lassudrie, Malwenn; Soudant, Philippe; Nicolas, Jean-Louis; Miner, Philippe; Le Grand, Jacqueline; Lambert, Christophe; Le Goïc, Nelly; Hégaret, Hélène; Fabioux, Caroline

    2016-04-01

    The Pacific oyster Crassostrea gigas is an important commercial species cultured throughout the world. Oyster production practices often include transfers of animals into new environments that can be stressful, especially at young ages. This study was undertaken to determine if a toxic Alexandrium bloom, occurring repeatedly in French oyster beds, could modulate juvenile oyster cellular immune responses (i.e. hemocyte variables). We simulated planting on commercial beds by conducting a cohabitation exposure of juvenile, "specific pathogen-free" (SPF) oysters (naïve from the environment) with previously field-exposed oysters to induce interactions with new microorganisms. Indeed, toxic Alexandrium spp. exposures have been reported to modulate bivalve interaction with specific pathogens, as well as physiological and immunological variables in bivalves. In summary, SPF oysters were subjected to an artificial bloom of Alexandrium catenella, simultaneously with a cohabitation challenge. Exposure to A. catenella, and thus to the paralytic shellfish toxins (PSTs) and extracellular bioactive compounds produced by this alga, induced higher concentration, size, complexity and reactive oxygen species (ROS) production of circulating hemocytes. Challenge by cohabitation with field-exposed oysters also activated these hemocyte responses, suggesting a defense response to new microorganism exposure. These hemocyte responses to cohabitation challenge, however, were partially inhibited by A. catenella exposure, which enhanced hemocyte mortality, suggesting either detrimental effects of the interaction of both stressors on immune capacity, or the implementation of an alternative immune strategy through apoptosis. Indeed, no infection with specific pathogens (herpesvirus OsHV-1 or Vibrio aesturianus) was detected. Additionally, lower PST accumulation in challenged oysters suggests a physiological impairment through alteration of feeding-related processes. Overall, results of this

  18. Comparative Study of Various Immune Parameters in Three Bivalve Species during a Natural Bloom of Dinophysis acuminata in Santa Catarina Island, Brazil

    Directory of Open Access Journals (Sweden)

    Danielle Ferraz Mello

    2010-05-01

    Full Text Available This study aimed to verify if Dinophysis acuminata natural blooms affected the immune system of three bivalves: the oyster, Crassostrea gigas, the mussel, Perna perna, and the clam, Anomalocardia brasiliana. Animals were obtained from a renowned mariculture farm in the southern bay of Santa Catarina Island during, and 30 days after (controls, an algal bloom. Various immunological parameters were assessed in the hemolymph of the animals: total and differential hemocyte counts, percentage of apoptotic hemocytes, protein concentration, hemagglutinating titer and phenoloxidase activity. The results showed that the mussel was the most affected species, with several altered immune parameters, whereas the immunological profile of clams and oysters was partially and completely unaffected, respectively.

  19. Disruption of amylase genes by RNA interference affects reproduction in the Pacific oyster Crassostrea gigas.

    Science.gov (United States)

    Huvet, Arnaud; Béguel, Jean-Philippe; Cavaleiro, Nathalia Pereira; Thomas, Yoann; Quillien, Virgile; Boudry, Pierre; Alunno-Bruscia, Marianne; Fabioux, Caroline

    2015-06-01

    Feeding strategies and digestive capacities can have important implications for variation in energetic pathways associated with ecological and economically important traits, such as growth or reproduction in bivalve species. Here, we investigated the role of amylase in the digestive processes of Crassostrea gigas, using in vivo RNA interference. This approach also allowed us to investigate the relationship between energy intake by feeding and gametogenesis in oysters. Double-stranded (ds)RNA designed to target the two α-amylase genes A and B was injected in vivo into the visceral mass of oysters at two doses. These treatments caused significant reductions in mean mRNA levels of the amylase genes: -50.7% and -59% mRNA A, and -71.9% and -70.6% mRNA B in 15 and 75 µg dsRNA-injected oysters, respectively, relative to controls. Interestingly, reproductive knock-down phenotypes were observed for both sexes at 48 days post-injection, with a significant reduction of the gonad area (-22.5% relative to controls) and germ cell under-proliferation revealed by histology. In response to the higher dose of dsRNA, we also observed reductions in amylase activity (-53%) and absorption efficiency (-5%). Based on these data, dynamic energy budget modeling showed that the limitation of energy intake by feeding that was induced by injection of amylase dsRNA was insufficient to affect gonadic development at the level observed in the present study. This finding suggests that other driving mechanisms, such as endogenous hormonal modulation, might significantly change energy allocation to reproduction, and increase the maintenance rate in oysters in response to dsRNA injection. PMID:25883379

  20. Identification and functional characterization of two executioner caspases in Crassostrea gigas.

    Directory of Open Access Journals (Sweden)

    Tao Qu

    Full Text Available Caspase-3 and caspase-7 are two key effector caspases that play important roles in apoptotic pathways that maintain normal tissue and organ development and homeostasis. However, little is known about the sequence, structure, activity, and function of effector caspases upon apoptosis in mollusks, especially marine bivalves. In this study, we investigated the possible roles of two executioner caspases in the regulation of apoptosis in the Pacific oyster Crassostrea gigas. A full-length caspase-3-like gene named Cgcaspase-3 was cloned from C.gigas cDNA, encoding a predicted protein containing caspase family p20 and p10 domain profiles and a conserved caspase active site motif. Phylogenetic analysis demonstrated that both Cgcaspase-3 and Cgcaspase-1 may function as effector caspases clustered in the invertebrate branch. Although the sequence identities between the two caspases was low, both enzymes possessed executioner caspase activity and were capable of inducing cell death. These results suggested that Cgcaspase-3 and Cgcaspase-1 were two effector caspases in C. gigas. We also observed that nucleus-localized Cgcaspase-3, may function as a caspase-3-like protein and cytoplasm-localized Cgcaspase-1 may function as a caspase-7-like protein. Both Cgcaspase-3 and Cgcaspase-1 mRNA expression increased after larvae settled on the substratum, suggesting that both caspases acted in several tissues or organs that degenerated after oyster larvae settlement. The highest caspase expression levels were observed in the gills indicating that both effector caspases were likely involved in immune or metabolic processes in C. gigas.

  1. Fabricational morphology of oblique ribs in bivalves.

    Science.gov (United States)

    Checa, Antonio G

    2002-11-01

    The formation of oblique ribs of bivalve shells usually has been attributed to processes of reaction-diffusion of morphogens from cell to cell at the mantle margin or neural activation and lateral inhibition in the mantle. In particular, such ribs appear with high rates of lateral diffusion. Nevertheless, theoretical models fail to explain either partially or wholly some varieties of oblique ribs. After surveying the modes of formation of the shell and oblique ribs by the bivalve mantle and associated fabricational defects, I have determined that the mantle is able to develop an elaborate behavior in order to displace the rib in a particular direction during growth. The mantle margin is, therefore, not only the shell-secreting organ, but also the main morphogenetic unit. In particular, there are two main fabricational strategies. In forms with strict contact guidance (SCG) the mantle is able to project far enough beyond the shell margins so as to feel the already formed reliefs and to align new growth increments of the ribs in the appropriate directions. The shell margin is always strongly reflected. In bivalves with reduced contact guidance plus constant lateral shift (RCG), the margin is usually acute and the information about ribs available to the mantle is reduced. During rib construction the mantle extrudes slightly from the shell edge and then pushes laterally by muscular action; in this way, the new growth increment of the rib is displaced laterally on a small scale. The contact-guidance model is supported also by the homogeneous structure of the shell-secreting mantle. From the morphogenetic standpoint, oblique ribs are related to commarginal ones and both differ completely from other ribbing patterns of bivalves. PMID:12353301

  2. Dynamics of sheet nacre formation in bivalves

    OpenAIRE

    Rousseau, Marthe; Meibom, Anders; Gèze, Marc; Bourrat, Xavier; Angellier, Martine; Lopez, Evelyne

    2009-01-01

    Formation of nacre (mother-of-pearl) is a biomineralization process of fundamental scientific as well as industrial importance. However, the dynamics of the formation process is still not understood. Here, we use scanning electron microscopy and high spatial resolution ion microprobe depth-profiling to image the full three-dimensional distribution of organic materials around individual tablets in the top-most layer of forming nacre in bivalves. Nacre formation proceeds by lateral, symmetric g...

  3. Markers associated with disease resistance in Eastern oysters, Crassostrea virginica

    Science.gov (United States)

    Eastern oyster, Crassostrea viginica, is an economically important aquaculture species in the USA, but production has been impacted by diseases such as dermo and MSX. Efforts have been put into the development of disease-resistant oyster lines using selective breeding techniques. However, these met...

  4. Tenacibaculum crassostreae sp. nov., isolated from the Pacific oyster, Crassostrea gigas.

    Science.gov (United States)

    Lee, Young Sun; Baik, Keun Sik; Park, So Yeon; Kim, Eun Mi; Lee, Dong-Heon; Kahng, Hyung-Yeel; Jeon, Che Ok; Jung, Jae Sung

    2009-07-01

    A rod-shaped, yellow-pigmented, aerobic, Gram-negative bacterium, designated strain JO-1(T), was isolated from an apparently healthy Pacific oyster, Crassostrea gigas, collected at Wan Island, Korea. It grew at 15-37 degrees C (optimum 30 degrees C) only in the presence of sea salts. Strain JO-1(T) hydrolysed casein, Tween 80 and starch. The major fatty acids were iso-C(15 : 0) (23.8 %), summed feature 3 (comprising C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH; 14.5 %) and iso-C(15 : 1) G (14.1 %). Analysis of the 16S rRNA gene sequence indicated that strain JO-1(T) was a member of the genus Tenacibaculum in the family Flavobacteriaceae, with sequence similarity of 94.6-97.8 % to the type strains of recognized members of the genus. The G+C content of the genomic DNA was 31.4 mol%. DNA-DNA relatedness levels between strain JO-1(T) and the five closest relatives, Tenacibaculum litoreum KCCM 42115(T), T. lutimaris KCTC 12302(T), T. aestuarii KCTC 12569(T), T. mesophilum DSM 13764(T) and T. adriaticum JCM 14633(T), were less than 28 %. Phylogenetic analyses and differences in physiological and biochemical characteristics suggested that strain JO-1(T) (=KCTC 22329(T) =JCM 15428(T)) should be classified as the type strain of a novel species within the genus Tenacibaculum, for which the name Tenacibaculum crassostreae sp. nov. is proposed. PMID:19542127

  5. Assimilation efficiencies and turnover rates of trace elements in marine bivalves: A comparison of oysters, clams and mussels

    Science.gov (United States)

    Reinfelder, J.R.; Wang, W.-X.; Luoma, S. N.; Fisher, N.S.

    1997-01-01

    Assimilation efficiencies (AEs) and physiological turnover-rate constants (k) of six trace elements (Ag, Am, Cd, Co, Se, Zn) in four marine bivalves (Crassostrea virginica Gmelin,Macoma balthica Linnaeus, Mercenaria mercenaria Linnaeus, and Mytilus edulis Linnaeus) were measured in radiotracer-depuration experiments. Egestion rates of unassimilated elements were highest during the first 24 h of depuration and declined thereafter. Significant egestion of unassimilated Co, however, continued for up to 5 d in Macoma balthica,Mercenaria mercenaria and Mytilus edulis. With the exception of the extremely low values for110 mAg, 109Cd, and 65Zn in C. virginica, physiological turnover-rate constants (k) showed no general pattern of variation among elements, bivalve species or food types, and were relatively invariant. Values from  ≤0.001 to 0.1 d−1 were observed, but excluding those for Co, most values were  ≤0.04 d−1. In all four species, the AEs of Ag, Am, and Co were generally lower than those of Cd, Se, and Zn. The AEs of Ag, Cd, Se, and Zn in these bivalves are directly related to the proportion of each element in the cytoplasmic fraction of ingested phytoplankton, indicating that >80% of elements in a prey alga's cytoplasm was assimilated. C. virginica, Macoma balthica, and Mercenaria mercenaria assimilated ∼36% of the Ag and Cd associated with the non-cytoplasmic (membrane/organelle) fraction of ingested cells in addition to the cytoplasmic fraction. The ratio of AE:k, which is proportional to the consumer–prey trace-element bioaccumulation factor (concentration in consumer:concentration in prey) was generally greater for Cd, Se, and Zn than for Ag, Am, and Co. This ratio was lowest in Mytilus edulis, suggesting that this bivalve, the most widely employed organism in global biomonitoring, is relatively inefficient at accumulating important elements such as Ag, Cd, and Zn from ingested phytoplankton.

  6. Pacific oyster (Crassostrea gigas) hemocyte are not affected by a mixture of pesticides in short-term in vitro assays.

    Science.gov (United States)

    Moreau, Pierrick; Burgeot, Thierry; Renault, Tristan

    2014-04-01

    Pesticides are frequently detected in estuaries among the pollutants found in estuarine and coastal areas and may have major ecological consequences. They could endanger organism growth, reproduction, or survival. In the context of high-mortality outbreaks affecting Pacific oysters, Crassostrea gigas, in France since 2008, it appears of importance to determine the putative effects of pesticides on oyster susceptibility to infectious agents. Massive mortality outbreaks reported in this species, mainly in spring and summer, may suggest an important role played by the seasonal use of pesticides and freshwater input in estuarine areas where oyster farms are frequently located. To understand the impact of some pesticides detected in French waters, their effects on Pacific oyster hemocytes were studied through short-term in vitro experiments. Bivalve immunity is mainly supported by hemocytes eliminating pathogens by phagocytosis and producing compounds including lysosomal enzymes and antimicrobial molecules. In this study, oyster hemocytes were incubated with a mixture of 14 pesticides and metaldehyde alone, a molecule used to eliminate land mollusks. Hemocyte parameters including dead/alive cells, nonspecific esterase activities, intracytoplasmic calcium, lysosome number and activity, and phagocytosis were monitored by flow cytometry. No significant effect of pesticides tested at different concentrations was reported on oyster hemocytes maintained in vitro for short-term periods in the present study. It could be assumed that these oyster cells were resistant to pesticide exposure in tested conditions and developing in vivo assays appears as necessary to better understand the effects of pollutants on immune system in mollusks. PMID:23818075

  7. Multi-species protein similarity clustering reveals novel expanded immune gene families in the eastern oyster Crassostrea virginica.

    Science.gov (United States)

    McDowell, Ian C; Modak, Tejashree H; Lane, Chris E; Gomez-Chiarri, Marta

    2016-06-01

    Comparative genomics research in non-model species has highlighted how invertebrate hosts possess complex diversified repertoires of immune molecules. The levels of diversification in particular immune gene families appear to differ between invertebrate lineages and even between species within lineages, reflecting differences not only in evolutionary histories, but also in life histories, environmental niches, and pathogen exposures. The goal of this research was to identify immune-related gene families experiencing high levels of diversification in eastern oysters, Crassostrea virginica. Families containing 1) transcripts differentially expressed in eastern oysters in response to bacterial challenge and 2) a larger number of transcripts compared to other species included those coding for the C1q and C-type lectin domain containing proteins (C1qDC and CTLDC), GTPase of the immune-associated proteins (GIMAP), scavenger receptors (SR), fibrinogen-C domain containing proteins (also known as FREPs), dopamine beta-hydrolase (DBH), interferon-inducible 44 (IFI44), serine protease inhibitors, apextrin, and dermatopontin. Phylogenetic analysis of two of the families significantly expanded in bivalves, IFI44 and GIMAP, showed a patchy distribution within both protostomes and deuterostomes, suggesting multiple independent losses and lineage-specific expansions. Increased availability of genomic information for a broader range of non-model species broadly distributed through vertebrate and invertebrate phyla will likely lead to improved knowledge on mechanisms of immune-gene diversification. PMID:27033806

  8. Intraspecific Variation in Mitogenomes of Five Crassostrea Species Provides Insight into Oyster Diversification and Speciation.

    Science.gov (United States)

    Ren, Jianfeng; Hou, Zhanhui; Wang, Haiyan; Sun, Ming-An; Liu, Xiao; Liu, Bin; Guo, Ximing

    2016-04-01

    A large number of Crassostrea oysters are found in Asia-Pacific. While analyses of interspecific variation have helped to establish historical relationships among these species, studies on intraspecific variation are necessary to understand their recent evolutionary history and current forces driving population biology. We resequenced 18 and analyzed 31 mitogenomes of five Crassostrea species from China: Crassostrea gigas, Crassostrea angulata, Crassostrea sikamea, Crassostrea ariakensis, and Crassostrea hongkongensis. Our analysis finds abundant insertions, deletions, and single-nucleotide polymorphisms in all species. Intraspecific variation varies greatly among species with polymorphic sites ranging from 54 to 293 and nucleotide diversity ranging from 0.00106 to 0.00683. In all measurements, C. hongkongensis that has the narrowest geographic distribution exhibits the least sequence diversity; C. ariakensis that has the widest distribution shows the highest diversity, and species with intermediate distribution show intermediate levels of diversity. Low sequence diversity in C. hongkongensis may reflect recent bottlenecks that are probably exacerbated by human transplantation. High diversity in C. ariakensis is likely due to divergence of northern and southern China populations that have been separated without gene flow. The significant differences in mitogenome diversity suggest that the five sister species of Crassostrea have experienced different evolutionary forces since their divergence. The recent divergence of two C. ariakensis populations and the C. gigas/angulata species complex provides evidence for continued diversification and speciation of Crassostrea species along China's coast, which are shaped by unknown mechanisms in a north-south divide. PMID:26846524

  9. Metabolic and histopathological alterations in the marine bivalve Mytilus galloprovincialis induced by chronic exposure to acrylamide.

    Science.gov (United States)

    Larguinho, Miguel; Cordeiro, Ana; Diniz, Mário S; Costa, Pedro M; Baptista, Pedro V

    2014-11-01

    Although the neurotoxic and genotoxic potential of acrylamide has been established in freshwater fish, the full breadth of the toxicological consequences induced by this xenobiotic has not yet been disclosed, particularly in aquatic invertebrates. To assess the effects of acrylamide on a bivalve model, the Mediterranean mussel (Mytilus galloprovincialis), two different setups were accomplished: 1) acute exposure to several concentrations of waterborne acrylamide to determine lethality thresholds of the substance and 2) chronic exposure to more reduced acrylamide concentrations to survey phases I and II metabolic endpoints and to perform a whole-body screening for histopathological alterations. Acute toxicity was low (LC50≈400mg/L). However, mussels were responsive to prolonged exposure to chronic concentrations of waterborne acrylamide (1-10mg/L), yielding a significant increase in lipid peroxidation plus EROD and GST activities. Still, total anti-oxidant capacity was not exceeded. In addition, no neurotoxic effects could be determined through acetylcholine esterase (AChE) activity. The findings suggest aryl-hydrocarbon receptor (Ahr)-dependent responses in mussels exposed to acrylamide, although reduced comparatively to vertebrates. No significant histological damage was found in digestive gland or gills but female gonads endured severe necrosis and oocyte atresia. Altogether, the results indicate that acrylamide may induce gonadotoxicity in mussels, although the subject should benefit from further research. Altogether, the findings suggest that the risk of acrylamide to aquatic animals, especially molluscs, may be underestimated. PMID:25262075

  10. Molluscs and echinoderms aquaculture: biological aspects, current status, technical progress and future perspectives for the most promising species in Italy

    Directory of Open Access Journals (Sweden)

    Antonio Pais

    2012-10-01

    Full Text Available Shellfish aquaculture is a widespread activity in the Italian peninsula. However, only two bivalve species are mainly cultured along the coastline of that country: the Mediterranean mussel Mytilus galloprovincialis and the Manila clam Venerupis philippinarum (Ruditapes philippinarum. By contrast, just a few other mollusc species of commercial interest are scarcely reared at a small-scale level. After analysing the current status of Italian shellfish production, this paper reports and discusses the potential for culturing several different invertebrate species [i.e., the European flat oyster Ostrea edulis, the grooved carpet shell Venerupis decussata (Ruditapes decussatus, the razor clams Ensis minor and Solen marginatus, the cephalopod Octopus vulgaris, and the purple sea urchin Paracentrotus lividus] in this country. In addition, a detailed overview of the progress made in aquacultural techniques for these species in the Mediterranean basin is presented, highlighting the most relevant bottlenecks and the way forward to shift from the experimental to the aquaculture phase. Finally, an outlook of the main economic and environmental benefits arising from these shellfish culture practices is also given.

  11. Molluscs of an intertidal soft-sediment area in China: Does overfishing explain a high density but low diversity community that benefits staging shorebirds?

    Science.gov (United States)

    Yang, Hong-Yan; Chen, Bing; Piersma, Theunis; Zhang, Zhengwang; Ding, Changqing

    2016-03-01

    The Yellow Sea is a key staging ground for shorebirds that migrate from Australasia to the Arctic each spring. A lot of attention has been paid to the impact of habitat loss due to land reclamation on shorebird survival, but any effects of overfishing of coastal resources are unclear. In this study, the abundance of molluscs in the intertidal mudflats of northern Bohai Bay on the Chinese Yellow Sea was investigated in 2008-2014 from the perspective of their importance as food for northward migrating shorebirds, especially Red Knots Calidris canutus. Numerically contributing 96% to the numbers of 17 species found in spring 2008, the bivalve Potamocorbula laevis (the staple food of Red Knots and other shorebirds) dominated the intertidal mollusc community. In the spring of 2008-2014, the densities of P. laevis were surprisingly high, varying between 3900 and 41,000 individuals/m2 at distinctly small sizes (average shell lengths of 1.1 to 4.8 mm), and thus reaching some of the highest densities of marine bivalves recorded worldwide and providing good food for shorebirds. The distribution of P. laevis was associated with relatively soft sediments in close proximity to the recently built seawalls. A monthly sampling programme showed steep seasonal changes in abundance and size. P. laevis were nearly absent in winter, each year settling on the intertidal mudflats anew. Peak densities were reached in spring, when 0-age P. laevis were 1-3 mm long. The findings point to a highly unusual demographic structure of the species, suggesting that some interfering factors are at play. We hypothesise that the current dominance of young P. laevis in Bohai Bay reflects the combined pressures of a nearly complete active removal of adult populations from mid-summer to autumn for shrimp farming (this clearing of adults may offer space for recruitment during the next spring) and low numbers of epibenthic predators of bivalves, such as shrimps and crabs, due to persistent overfishing in

  12. Biomimetic and bio-inspired uses of mollusc shells.

    Science.gov (United States)

    Morris, J P; Wang, Y; Backeljau, T; Chapelle, G

    2016-06-01

    Climate change and ocean acidification are likely to have a profound effect on marine molluscs, which are of great ecological and economic importance. One process particularly sensitive to climate change is the formation of biominerals in mollusc shells. Fundamental research is broadening our understanding of the biomineralization process, as well as providing more informed predictions on the effects of climate change on marine molluscs. Such studies are important in their own right, but their value also extends to applied sciences. Biominerals, organic/inorganic hybrid materials with many remarkable physical and chemical properties, have been studied for decades, and the possibilities for future improved use of such materials for society are widely recognised. This article highlights the potential use of our understanding of the shell biomineralization process in novel bio-inspired and biomimetic applications. It also highlights the potential for the valorisation of shells produced as a by-product of the aquaculture industry. Studying shells and the formation of biominerals will inspire novel functional hybrid materials. It may also provide sustainable, ecologically- and economically-viable solutions to some of the problems created by current human resource exploitation. PMID:27083864

  13. Amylase polymorphism affects growth in the cupped oyster Crassostrea gigas

    OpenAIRE

    Huvet, Arnaud; Samain, Jean-francois; Boudry, Pierre; Bedier, Edouard; Ropert, Michel; Van Wormhoudt, A

    2005-01-01

    The better understanding of physiological and environmental factors that determine optimal food conversion efficiencies is of major interest for the cupped oyster Crassostrea gigas for which the strong increase of aquaculture has been correlated in France with a decrease in productivity due to competition between aquatic species for limited food supplies at grow-out sites. To investigate the non-neutrality of the polymorphism of amylase, a key enzyme for carbohydrate assimilation, in oyster p...

  14. Sensory and Chemical Characteristics of Eastern Oysters(Crassostrea virginica)

    OpenAIRE

    Chen, Luman

    2011-01-01

    Eastern Oysters, or Crassostrea virginica, are an important dietary component in the Chesapeake region and have supported a major fishery in the Chesapeake for more than 100 years. Virginia oysters do not always receive attention in up-scale markets. It is possible that the lack of information on sensory characteristics of Chesapeake oysters may contribute to this problem. In order to differentiate Chesapeake oysters from other oysters, a descriptive sensory test (n=8) was conducted and chemi...

  15. Adult Pacific Oyster (Crassostrea gigas) May Have Light Sensitivity

    OpenAIRE

    Wu, Changlu; Wang, Jiao; Yang, Yanjian; Li, Zhuang; Guo, Ting; Li, Yongchuan; Wang, Xiaotong

    2015-01-01

    Light-sensitivity is an important aspect of mollusk survival as it plays a vital role in reproduction and predator avoidance. In the Pacific oyster Crassostrea gigas light sensitivity has been demonstrated in the larval stage but has not yet been conclusively demonstrated in adult oysters. In this paper we describe an experiment which was undertaken to determine if adult Pacific oysters were sensitive to light. One LED flashlight was used to shine light onto adult oysters while they were filt...

  16. Phylogeny and diversification patterns among vesicomyid bivalves.

    Directory of Open Access Journals (Sweden)

    Carole Decker

    Full Text Available Vesicomyid bivalves are among the most abundant and diverse symbiotic taxa in chemosynthetic-based ecosystems: more than 100 different vesicomyid species have been described so far. In the present study, we investigated the phylogenetic positioning of recently described vesicomyid species from the Gulf of Guinea and their western Atlantic and Pacific counterparts using mitochondrial DNA sequence data. The maximum-likelihood (ML tree provided limited support for the recent taxonomic revision of vesicomyids based on morphological criteria; nevertheless, most of the newly sequenced specimens did not cluster with their morphological conspecifics. Moreover, the observed lack of geographic clustering suggests the occurrence of independent radiations followed by worldwide dispersal. Ancestral character state reconstruction showed a significant correlation between the characters "depth" and "habitat" and the reconstructed ML phylogeny suggesting possible recurrent events of 'stepwise speciation' from shallow to deep waters in different ocean basins. This is consistent with genus or species bathymetric segregation observed from recent taxonomic studies. Altogether, our results highlight the need for ongoing re-evaluation of the morphological characters used to identify vesicomyid bivalves.

  17. Study on the bioaccumulation of Polonium-210 on bivalve indicator organisms of Tamilnadu and Pondicherry coast (East Coast of India)

    International Nuclear Information System (INIS)

    210Po is a major contributor (90%) of the natural radiation dose from alpha-emitting radionuclides, received by most marine organisms. Among marine organisms, benthic fauna are superior to many other biological groups, since they could be monitored due to their sedentary habits and then must either adapt to environmental stress or perish. They also reflect the water conditions not only at the time of sampling but also for some past time as well. The affinity of 210Po for protein enables it to pass through the food chain, and increased body burdens of 210Po have been found where diets include protein-rich meat and seafood. The present study was launched to evaluate the rate of accumulation of 210Po in the benthic bivalve molluscs such as Perna indica, P.viridis, Meretrix casta, Cardium coronatum, Gafrarium tumidum, Paphia textrix, Vellorita cyprinodea and Pinctada sp., of Tamilnadu and Pondicherry coast. Water samples, sediments and bivalves were collected from Gulf of Mannar (6 sampling stations), Palk Strait (8 sampling stations) of Tamilnadu and Pondicherry (6 sampling stations). 210Po determination as made was as per standard protocols. The results showed that 210Po concentration in coastal waters of Gulf of Mannar, Palk Strait and Pondicherry ranged 0.5 - 2.83 mBq/l (mean 1.33 mBq/I), 2.14 - 32.14 mBq/l (mean 15.3 mBq/l) and 1.36 - 2.0 mBq/1 (mean 1.59 mBq/1) respectively. The sediments maintained higher level of 210Po (mean value of 3.62 Bq/kg in Gulf of Mannar, 107.9 Bq/kg in Palk Strait and 3.0 Bq/kg in Pondicherry) than water. The 210Po rich sediment therefore serves as a vital link in the transfer of Polonium from water to the marine organisms. The concentration of 210Po in eight species of bivalves collected from the study area, recorded a maximum level ranging from 65.2 to 2668.9 Bq/kg in soft tissues and from 1.19 to 15.3 Bq/kg in shells. The bioaccumulation ability in bivalve species with reference to 210Po was observed to be highly variable among the

  18. The estimation of DEB parameters for various Northeast Atlantic bivalve species

    Science.gov (United States)

    van der Veer, Henk W.; Cardoso, Joana F. M. F.; van der Meer, Jaap

    2006-08-01

    Dynamic energy budgets are used for the description of the energy flow through individual organisms from the assimilation of food to the utilisation for maintenance, growth, development and reproduction. In this paper, a procedure for estimation of the parameters of Kooijman's Dynamic Energy Budget (DEB) model is introduced and subsequently parameters are estimated for the following Northeast Atlantic bivalve species: the Baltic clam Macoma balthica (L.), the sandgaper Mya arenaria L., the cockle Cerastoderma edule (L.), the blue mussel Mytilus edulis L. and the Pacifc oyster Crassostrea gigas (Thunberg, 1793). For none of the species, a complete set of parameters could be compiled. A special protocol was developed to account for missing values and to achieve consistency between parameters. Species were similar in their optimal temperature range, as reflected in a common Arrhenius temperature of 5800 K, which corresponds with a Q 10 of 2. Differences between species were observed in width of the optimal temperature range. The taxonomic relatedness between species was reflected in similar volume-specific maintenance costs, costs for growth and almost similar maximum storage density of energy. Species differed in their maximum surface area-specific assimilation rate by a factor of 6 and in the fraction of energy allocated to reproduction (ranging from 0.15 to 0.50). These differences are reflected in the maximum theoretical total shell length of the species, which varied from about 3 cm in M. balthica, 6 cm in C. edule, 15 cm in M. arenaria and M. edulis and 45 cm in C. gigas.

  19. INTRODUCTION After fourteen years of pioneering systematic work spanning from 1996 to 2010, carried out in the territory of Santa Catarina State, SC, within the Brazilian Southern region, framed in the socalled Atlantic Slope of the Southern Cone of South America (Agudo-Padrón, 2008a, a basic list of continental (land and freshwater and marine mollusc species was compiled. Besides constant interactions and consultations with numerous national and international specialists, such a list was mostly based on available literature and/or analyses of voucher specimens deposited in collections belonging to research centers or environmental education institutes. To date (up to the first semester of 2010, this list comprises a total of 878 taxa (species and subspecies, including 695 marine and 183 continental forms, and these numbers are likely to increase as field surveys ensue. In the present study, results obtained from the author’s active participation in three recent regional field sampling expeditions dealing with marine and continental mollusc taxa, are reported. I. Official State program for listing and control of invasive exotic species Starting from November 2009, and for the first time in the history of Santa Catarina State, the presence of invasive allochthonous mollusc species in Santa Catarina State was studied and discussed through the organisation of seminars by the Official Foundation for the Environment of the State of Santa Catarina (Fundação do Meio Ambiente – FATMA jointly with the Hórus Institute for Development and Environmental Conservation (Instituto Hórus de Desenvolvimento e Conservação Ambiental, with the main goal to compile the Official State List of Species. To date, the occurrence of a total of twenty allochthonous (exotic forms of mollusc species has been confirmed, 14 Gastropoda and 6 Bivalvia [namely, 11 terrestrial gastropods, 5 freshwater taxa (3 gastropods and 2 bivalves and 4 marine bivalves]. Taking into account the

    Directory of Open Access Journals (Sweden)

    A. Ignacio Agudo-Padrón

    2011-03-01

    Full Text Available Available knowledge of malacofauna (mollusc species conservation in the territory of Santa Catarina State,SC, central Southern Brazil region, is shortly analyzed and discussed herein. Present data originate from theauthor's active participation in three recent regional unpublished events dealing with biodiversity conservationin the State, carried out to cope the sensitive lack of population studies which is the main difficulty to face inorder to provide accurate and detailed evaluations on biodiversity and its conservation status.

  20. Příspěvek k poznání vodních měkkýšů evropsky významné lokality Bystřice se zaměřením na populaci velevruba tupého (Unio crassus A contribution to the knowledge of aquatic molluscs of the Bystřice SCI focused on the population of Unio crassus

    Directory of Open Access Journals (Sweden)

    Luboš Beran

    2011-03-01

    Full Text Available This paper brings results of a malacological survey of the Bystřice River on the territory of the Site of Community Importance (SCI Bystřice (Eastern Bohemia, Czech Republic. The research was focused on the population of endangered bivalve Unio crassus which is the main object of conservation of this SCI. Twenty one species of aquatic molluscs (11 gastropods, 10 bivalves were found in 2010. Most of the molluscs belong to common and widespread species. Altogether 26 species have been found during research in the Bystřice River since 2000. Expansion of non-native species Potamopyrgus antipodarum and Physella acuta is the most visible change in comparison with the previous research. The research in 2010 confirmed existence of the occurrence of Unio crassus all over the SCI and also upstream of this site. The population density documented in 2010 was higher than that found during the previous research. In the upper part of the SCI, the density of U. crassus population was at least 1 ind./1 m of the river stream while in the lower part it did not exceed 1 ind. per 10 m of the river. The reason was the canalisation of the river and the absence of suitable sediments. The occurrence of the bivalve was not recorded downstream of the SCI.

  1. Rodriguesic acids, modified diketopiperazines from the gastropod mollusc Pleurobranchus areolatus

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Fabio R.; Santos, Mario F.C.; Berlinck, Roberto G.S., E-mail: rgsberlinck@iqsc.usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Quimica; Williams, David E.; Andersen, Raymond J. [Departments of Chemistry and Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver (Canada); Padula, Vinicius [SNSB-Zoologische Staatssammlung München, München, Germany and Department Biology II and GeoBio-Center, Ludwig-Maximilians-Universität München, (Germany); Ferreira, Antonio G. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica

    2014-04-15

    In the present investigation, two specimens of the nudipleuran mollusc Pleurobranchus areolatus have shown to accumulate oxidized rodriguesin A derivatives. Rodriguesic acid presents a carboxylic acid replacing the terminal methyl group of the alkyl chain of rodriguesin A. A hydroxamate group was also present on the diketopiperazine moiety of a rodriguesic acid derivative. The structures of both rodriguesic acid and of rodriguesic acid hydroxamate have been established by analysis of spectroscopic data, including their absolute configuration. Two methyl esters of the rodriguesic acids have been isolated as major compounds, but were considered to be isolation artifacts. (author)

  2. A PCR-based diagnostic assay for the detection of Roseovarius crassostreae in Crassostrea virginica affected by juvenile oyster disease (JOD)

    Science.gov (United States)

    Maloy, A.P.; Barber, B.J.; Boettcher, K.J.

    2005-01-01

    We have developed a PCR-assay for the diagnosis of juvenile oyster disease (JOD) based on the detection of Roseovarius crassostreae directly from affected oysters. Species-specific primers are used to amplify the 16S-23S rDNA internal transcribed spacer (ITS) of R. crassostreae, and confirmation of product identity is accomplished by restriction enzyme analysis. No false positives were obtained with either closely related bacterial species or from other DNAs present in oyster samples. The assay has the potential to detect as few as 10 cells of R. crassostreae per oyster when samples are taken from the inner valve surfaces of the animal. Inclusion of material from soft body surfaces is not necessary, and may reduce sensitivity approximately 10-fold. In a JOD-affected population, a positive PCR result was obtained from all oysters from which these bacteria were subsequently cultured. The assay also detected the presence of R. crassostreae in 2 oysters from which no R. crassostreae isolates were recovered. No R. crassostreae was detected by either PCR or bacteriology in oysters from a population that was not exhibiting JOD-signs. This assay is expected to advance regional disease management efforts and provide valuable insights into the disease process and epizootiology of JOD. ?? Inter-Research 2005.

  3. Evaluation of the concentration of heavy metals in sea water, silt and rock oysters, Crassostrea iridescens, from Manzanillo bay

    International Nuclear Information System (INIS)

    Some essential metals such as Fe, Ni, Cu and Zn were evaluated by X-ray spectroscopy in water, soil and rock oyster Crassostrea iridescens from Manzanillo Bay. Four samplings were taken every two months during 1991. Concentration range on liofilized oysters for Fe was determined between 76 and 172 μ g/g dry weight, Ni 9-21 μ g/g dry weight, Cu 21-123 μ g/g dry weight and Zn 216-885 μ g/g dry weight. Ni concentration was above the toxicological tolerance level for crustaceans (5 μ g/g); Cu was above maxima permission limited (MPL) from FAO for molluscs (70 μ g/g); Zn was below MPL for oysters (1000 μ g/g). For Fe there is no MPL for oyster or any other aquatic organisms. Concentration and accumulation factors for the elements measured suggested the filtration oyster activity. Fe concentration range in water was 27-2266 μ g/l. This value is above the ecological aquatic life criteria in Mexico (50 μ g/l). For Cu the concentration range was 4-536 μ g/l., which is above the MPL for Mexican Legislation (5 μ g/l). Chemical elements detected in soil were the essential metal mentioned before. However, the heavy metals concentrations for soil, from Manzanillo Bay, were higher than those reported in other polluted regions in both Mexican coasts. Concentration range for Fe was 30661-76332 μ g/g, Ni 19-180 μ g/g, Cu 56-270 μ g/g and Zn 33-1377 μ g/g. Contamination problem in Manzanillo Bay must be considered as an evidence of potential risk, since the essential metals are reaching levels that could endanger aquatic life. (Author). 87 refs, 20 figs, 6 tabs

  4. Development and validation of OECD test guidelines on mollusc reproductive toxicity tests

    DEFF Research Database (Denmark)

    Lagadic, Laurent; Holbech, Henrik; hutchinson, tom;

    Validated guidelines in line with the OECD Conceptual Framework for the Testing and Assessment of Endocrine Disrupting Chemicals (EDTA) have been developed for rodents, amphibians, fish, aquatic insects and crustaceans. Only aquatic arthropods have been considered in this test battery although the...... comparison of endpoints relevant for reproduction in invertebrates often shows a much higher sensitivity in molluscs vs. e.g. daphnids. The OECD test guideline programme has thus been extended to cover reproduction effects of chemicals in molluscs. Existing mollusc toxicity test protocols have been reviewed...... mollusc reproduction test guideline will be developed describing partial- and full- life-cycle test protocols in these species, so as to propose a balanced suite of apical mollusc toxicity tests applicable for the assessment of any type of chemical, including endocrine disruptors, as level 4 and 5 assays...

  5. The immunological capacity in the larvae of Pacific oyster Crassostrea gigas.

    Science.gov (United States)

    Song, Xiaorui; Wang, Hao; Xin, Lusheng; Xu, Jiachao; Jia, Zhihao; Wang, Lingling; Song, Linsheng

    2016-02-01

    As the immune system has not fully developed during early developmental stages, bivalve larvae are more susceptible for pathogens, which frequently leads to the significant mortality in hatcheries. In the present study, the development of immune system and its response against bacteria challenge were investigated in order to characterize the repertoire of immunological capacity of Pacific oyster Crassostrea gigas during the ontogenesis. The phagocytosis was firstly observed in the early D-veliger larvae (17 hpf), especially in their velum site, which indicated the appearance of functional hemocytes during early D-veliger larvae stage. The whole-mount immunofluorescence assay of three pattern recognition receptors (integrin β-1, caspase-3 and C-type lectin 3) and one immune effector gene (IL17-5) was performed in blastula, early D-veliger and umbo larvae, suggested that velum and digestive gland were the potential sites of immune system in the larvae. The lowest activities of antioxidant enzymes (superoxide dismutase and catalase) and hydrolytic enzyme (lysozyme), as well as descended expression levels of 12 immune genes at the transition between embryogenesis and planktonic, indicated that the larvae at hatching (9 hpf) were in hypo-immunity. While the ascending activities of enzymes and expression levels of seven immune genes during the trochophore stage (15 hpf) suggested the initiation of immune system. The steadily increasing trend of all the 12 candidate genes at the early umbo larvae (120 h) hinted that the immune system was well developed at this stage. After bacterial challenge, some immune recognition (TLR4) and immune effector (IL17-5 and defh2) genes were activated in blastula stage (4 hpf), and other immune genes were up regulated in D-veliger larvae, indicating that the zygotic immune system could respond earlier against the bacterial challenge during its development. These results indicated that the cellular and humoral immune components

  6. PERSISTANCE OF VIRUSES IN OYSTER (CRASSOSTREA VIRGINICA) HEMOCYTES

    Science.gov (United States)

    Seafood is listed as one of the top three causes of human virus infection by foodborne products. The goal of this study is to determine why human enteric viruses such as hepatitis A (HAV) and Norovirus (NV) readily persist within bivalves. Shellfish bioaccumulate water-borne pathogens and concentra...

  7. Geography of end-Cretaceous marine bivalve extinctions

    Science.gov (United States)

    Raup, David M.; Jablonski, David

    1993-01-01

    Analysis of the end-Cretaceous mass extinction, based on 3514 occurrences of 340 genera of marine bivalves (Mollusca), suggests that extinction intensities were uniformly global; no latitudinal gradients or other geographic patterns are detected. Elevated extinction intensities in some tropical areas are entirely a result of the distribution of one extinct group of highly specialized bivalves, the rudists. When rudists are omitted, intensities at those localities are statistically indistinguishable from those of both the rudist-free tropics and extratropical localities.

  8. Lower Jurassic beds with bivalves in south Slovenia

    OpenAIRE

    Irena Debeljak; Stanko Buser

    1995-01-01

    The Lower Jurassic beds of south Slovenia outcrop on a surface of several hundred km^ with their thickness in places exceeding 300 meters. They were deposited on the Dinaric Carbonate Platform. In them rich accumulations of characteristic bivalves occur that in Pliensbachian and Toarcian inhabited the wide interconnected shallow water regions of the western and southern margins of Tethysand the eastern Pacific. The most interesting are three large bivalve species:Lithiotis problematica, Cochl...

  9. Characteristics of bivalve diversity in typical habitats of China seas

    OpenAIRE

    Fengshan Xu; Junlong Zhang

    2011-01-01

    With vast sea areas, long coastline and complex environmental conditions, the China seas contain various habitats for bivalves. The diversity characteristics of some typical habitats can reflect the molluscan fauna of China seas. Based on our years of work and records from malacologists home and abroad, the bi-valve diversity, habitats and ecological habits in different environments are described, and the distribution characters in different sea areas are analysed. Due to the effects of coast...

  10. Effects of chronic exposure to ionising radiation in the Pacific oyster Crassostrea gigas

    International Nuclear Information System (INIS)

    The Cotentin peninsula (Normandy, France) hosts nuclear industry facilities which operate with controlled discharges of radionuclides in the marine environment. Compared to natural radioactivity, the increase by artificial radionuclides is small but constant. As a consequence, marine species are chronically exposed to low additional doses of ionizing radiation (IR). The effects of chronic exposure to radionuclides were investigated in early stages of development of the Japanese oyster Crassostrea gigas. On the basis of literature, mollusks are expected to be particularly resistant to acute IR (UNSCEAR, 1996. Sources and effects of ionizing radiation. Report to the General Assembly, with Scientific Annex. 86 p). Two different chronic exposure conditions consisted in external (137Cs) and internal (241Am) irradiation for two weeks. Biological endpoints were analyzed in parallel at both the integrated (growth) and molecular (target stress gene expression) levels. To identify potential biological targets of IR, oysters were first exposed to very high dose rates and radionuclide activities with the perspective to reduce the levels and to derive dose-response curves. Although the initial exposure levels (137Cs 30 000 μGy.h-1; 241Am 57 000 Bq.L-1) were many orders of magnitude higher than those encountered in the natural environment, no significant change in the measured parameters was observed. This result was surprising because data from the literature showed that exposure of mussel Mytilus edulis to 3H at lower doses rates (10-100 μGy.h-1) induced DNA damage in hemocytes (Jha et al., 2005. Impact of low doses of tritium on the marine mussel, Mytilus edulis: Genotoxic effects and tissue-specific bioconcentration. Mutation Research/Genetic Toxicology and Environmental Mutagenesis 586, 47-57). To understand this apparent discrepancy between those two filtering bivalves, a new experiment was performed to compare the response of oyster exposed to 3H in the same condition

  11. Effects of chronic exposure to ionising radiation in the Pacific oyster Crassostrea gigas

    Energy Technology Data Exchange (ETDEWEB)

    Fievet, B.; Devos, A.; Voiseux, C.; Leconte-Pradines, C. [Institut de Radioprotection et de Surete' Nucleaire (France); Dallas, L.; Jha, A. [University of Plymouth (United Kingdom)

    2014-07-01

    The Cotentin peninsula (Normandy, France) hosts nuclear industry facilities which operate with controlled discharges of radionuclides in the marine environment. Compared to natural radioactivity, the increase by artificial radionuclides is small but constant. As a consequence, marine species are chronically exposed to low additional doses of ionizing radiation (IR). The effects of chronic exposure to radionuclides were investigated in early stages of development of the Japanese oyster Crassostrea gigas. On the basis of literature, mollusks are expected to be particularly resistant to acute IR (UNSCEAR, 1996. Sources and effects of ionizing radiation. Report to the General Assembly, with Scientific Annex. 86 p). Two different chronic exposure conditions consisted in external ({sup 137}Cs) and internal ({sup 241}Am) irradiation for two weeks. Biological endpoints were analyzed in parallel at both the integrated (growth) and molecular (target stress gene expression) levels. To identify potential biological targets of IR, oysters were first exposed to very high dose rates and radionuclide activities with the perspective to reduce the levels and to derive dose-response curves. Although the initial exposure levels ({sup 137}Cs 30 000 μGy.h{sup -1}; {sup 241}Am 57 000 Bq.L{sup -1}) were many orders of magnitude higher than those encountered in the natural environment, no significant change in the measured parameters was observed. This result was surprising because data from the literature showed that exposure of mussel Mytilus edulis to {sup 3}H at lower doses rates (10-100 μGy.h{sup -1}) induced DNA damage in hemocytes (Jha et al., 2005. Impact of low doses of tritium on the marine mussel, Mytilus edulis: Genotoxic effects and tissue-specific bioconcentration. Mutation Research/Genetic Toxicology and Environmental Mutagenesis 586, 47-57). To understand this apparent discrepancy between those two filtering bivalves, a new experiment was performed to compare the response

  12. The Pacific Oyster (Crassostrea gigas) in the Isefjord, Denmark

    OpenAIRE

    Wang, Jing; Chrisoffersen, Kenn; Buck, Sine; Tao, Ying

    2007-01-01

    The Pacific Oyster (Crassostrea gigas) is one of the alien species that were introduced and cultured in Europe. Researches show that C. gigas has reached a high density in the Limfjord as oyster reefs in recent years. Since 1986, several attempts for cultivations of C. gigas had been done in the Isefjord, and stopped in 1998. Till now, there is no previously specific study on C. gigas done in that area. In order to investigate the density of pacific oysters in the Isefjord, and to estimate wh...

  13. The complete mitochondrial genome of Crassostrea gasar (Bivalvia: Ostreidae).

    Science.gov (United States)

    Cavaleiro, Nathalia P; Solé-Cava, Antonio M; Melo, Cláudio M R; de Almeida, Luiz G; Lazoski, Cristiano; Vasconcelos, Ana Tereza R

    2016-07-01

    The complete mitochondrial genome of Crassostrea gasar was sequenced using the Ion Proton technology in combination with 454 Roche GS-FLX plataform data. We assembled a 17,686 bp complete circular mitochondrial genome, containing 13 protein-coding genes, a major non-coding region (MNR), two ribosomal RNA genes and 24 transfer RNA genes. Phylogenetic analysis of concatenated amino acid sequences from mitochondria showed monophyletic clades formed with high bootstrap values. This is the first complete mitochondrial sequence of an oyster from South America. Mitogenome sequence was deposited in GenBank under the accession number KR856227. PMID:27158791

  14. The invasive Pacific oyster, Crassostrea gigas, in Scandinavia coastal waters

    DEFF Research Database (Denmark)

    Dolmer, Per; Holm, Mark Wejlemann; Strand, Åsa;

    visualized the need for a continued collaboration between scientists in the Scandinavian countries, as the bio-invasion is a cross-border issue and management actions then have to be synchronized, and based on a “state of the art” knowledge of the Scandinavian bio-invasion of the species. The risk assessment......A massive invasion of the Pacific oyster, Crassostrea gigas , has occurred in Scandinavia during the last decade. The introduction and dispersal was described through collaboration between scientists from Sweden, Denmark and Norway. This work has been followed up by national activities that clearly...

  15. 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.

  16. Determination of the variability of both hydrophilic and lipophilic toxins in endemic wild bivalves and carnivorous gastropods from the southern part of Chile.

    Science.gov (United States)

    Zamorano, Ruben; Marín, Michelle; Cabrera, Fabiola; Figueroa, Diego; Contreras, Cristóbal; Barriga, Andrés; Lagos, Néstor; García, Carlos

    2013-01-01

    The aim of this study was to analyse and determine the composition of paralytic shellfish poisoning (PSP) toxins and lipophilic toxins in the Region of Aysén, Chile, in wild endemic mussels (Mytilus chilensis, Venus antiqua, Aulacomya ater, Choromytilus chorus, Tagelus dombeii and Gari solida) and in two endemic carnivorous molluscs species (Concholepas concholepas and Argobuccinum ranelliforme). PSP-toxin contents were determined by using HPLC with fluorescence detection, while lipophilic toxins were determined by using LC-MS/MS. Mean concentrations for the total of PSP toxins were in the range 55-2505 μg saxitoxin-equivalent/100 g. The two most contaminated samples for PSP toxicity were bivalve Gari solida and carnivorous Argobuccinum ranelliforme with 2505 ± 101 and 1850 ± 137 μg saxitoxin-equivalent/100 g, respectively (p < 0.05). The lipophilic toxins identified were okadaic acid, dinophysistoxin-1 (DTX-1), azaspiracid-1 (AZA-1), pectenotoxin-2 (PTX-2) and yessotoxins (YTX). All analysed molluscs contained lipophilic toxins at levels ranging from 56 ± 4.8 to 156.1 ± 8.2 μg of okadaic acid-equivalent/kg shellfish together with YTX at levels ranging from 1.0 ± 0.1 to 18 ± 0.9 μg of YTX-equivalent/kg shellfish and AZA at levels ranging from 3.6 ± 0.2 to 31 ± 2.1 μg of AZA-equivalent/kg shellfish. Furthermore, different bivalves and gastropods differ in their capacity of retention of lipophilic toxins, as shown by the determination of their respective lipophilic toxins levels. In all the evaluated species, the presence of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods was not identified, in contrast to the identification of PSP toxins, where the profiles identified in the different species are directly related to biotransformation processes. Thus, this study provides evidence that the concentration of toxins in the food intake of the evaluated species (Bivalvia and Gastropoda class) determines the degree of

  17. Marine diatoms sustain growth of bivalves in a Mediterranean lagoon

    Science.gov (United States)

    Pernet, Fabrice; Malet, Nathalie; Pastoureaud, Annie; Vaquer, André; Quéré, Claudie; Dubroca, Laurent

    2012-02-01

    Carbon stable isotopes and fatty acids were measured in the suspended particulate organic matter (POM) of the Thau lagoon to study its qualitative temporal changes in relation to environmental factors and to identify the food sources of bivalves over a one-yr-cycle in relation to their growth. Reciprocally, the impact of shellfish farming on POM was also studied. Oysters and mussels were sampled and measured for biometry, stable isotopes and fatty acid composition. Water samples were collected at two sites, both inside and outside of the shellfish farming area, to determine concentrations in POM, chlorophyll a (Chl a) and stable isotopes. Carbon isotopes and fatty acids in bivalves reflected seasonal changes in food sources, which varied consistently with the environment. Seasonal changes in δ13C and fatty acids in the bivalves suggested that dietary phytoplankton contribution varied according to season. Terrestrial organic matter and bacteria can contribute to the diet of bivalves during non-bloom periods. Mussels seemed to rely more on diatoms and less on terrestrial organic matter and bacteria than oysters did, particularly when phytoplankton biomass was low during the summer. Although one- and two-yr-old oysters showed similar δ13C, their fatty acid dynamics differed slightly. Periods of high growth rate in bivalves were mainly fuelled by diatoms, thus highlighting the importance of seasonal blooms of microphytoplankton during the critical period of bivalve growth and gamete production. Although there was no significant effect of shellfish farms on Chl a and POM δ13C, consistent differences indicate that stable isotopes could be used successfully to investigate the effects of bivalve aquaculture.

  18. Total mercury content in fish und molluscs from Adriatic sea

    International Nuclear Information System (INIS)

    In regard to a long known and still persisting problem of the ecosystem loaded with mercury, total mercury contents in different species of fish and molluscs in the Adriatic Sea have been followed in an interval of 12 years. Total mercury concentrations were determined by cold vapour atomic adsorption spectrometry (CVAAS) at 253. 7 nm after digestion of the edible of fish tissues. The results of analysis reveal positive shifts and unlike the samples in a previous study all the investigated samples meet the conditions of the Public Health Regulations on the quantity of pesticides, mycotoxins, metals, histamine and similar substances that may occur in foodstuff and on other conditions as to the standards of foodstuff and objects of general use, which fixed the total Hg content at maximum of 0.5 mg/kg on the basis of fresh mass. (orig.)

  19. Total mercury content in fish und molluscs from Adriatic sea

    Energy Technology Data Exchange (ETDEWEB)

    Vedrina-Dragojevic, I. [Zagreb Univ. (Croatia). Dept. of Food Chemistry; Dragojevic, D. [Water Quality Dept., Waterworks, Zagreb (Croatia); Bujan, M. [Zagreb Univ. (Croatia). Dept. of Chemistry

    2002-07-01

    In regard to a long known and still persisting problem of the ecosystem loaded with mercury, total mercury contents in different species of fish and molluscs in the Adriatic Sea have been followed in an interval of 12 years. Total mercury concentrations were determined by cold vapour atomic adsorption spectrometry (CVAAS) at 253. 7 nm after digestion of the edible of fish tissues. The results of analysis reveal positive shifts and unlike the samples in a previous study all the investigated samples meet the conditions of the Public Health Regulations on the quantity of pesticides, mycotoxins, metals, histamine and similar substances that may occur in foodstuff and on other conditions as to the standards of foodstuff and objects of general use, which fixed the total Hg content at maximum of 0.5 mg/kg on the basis of fresh mass. (orig.)

  20. Granular chitin in the epidermis of nudibranch molluscs.

    Science.gov (United States)

    Martin, Rainer; Hild, Sabine; Walther, Paul; Ploss, Kerstin; Boland, Wilhelm; Tomaschko, Karl-Heinz

    2007-12-01

    Chitin is usually found in stiff extracellular coatings typified by the arthropod exoskeleton, and is not associated with the soft, flexible mollusc skin. Here, we show, however, that chitin in nudibranch gastropods (Opisthobranchia, Mollusca) occurs as intracellular granules that fill the epidermal cells of the skin and the epithelial cells of the stomach. In response to nematocysts fired by tentacles of prey Cnidaria, the epidermal cells of eolid nudibranchs (Aeolidacea) release masses of chitin granules, which then form aggregates with the nematocyst tubules, having the effect of insulating the animal from the deleterious action of the Cnidaria tentacles. Granular chitin, while protecting the animal, does not interfere with the suppleness and flexibility of the skin, in contrast to the stiffness of chitin armor. The specialized epidermis enables nudibranchs to live with and feed on Cnidaria. PMID:18083970

  1. Karyotypes of three species of the marine Veneroida molluscs

    Institute of Scientific and Technical Information of China (English)

    Sun Zhenxing; Shao Yanqun; Guo Shengchao; Qin Yan; Yang Aiguo

    2003-01-01

    The karyotypes of three species of marine Veneroida molluscs, Solen grandis Dunker,Saxidomus purpuratus Sowerby and Mactra chinensis Philippi were studied by using the adult gill tissues. The chromosomes were prepared through injecting phytohemagglutinin (PHA) and colchicine, hypotonic treatment, chopping air-dry, and squashing technology. The results show that the diploid chromosome numbers of the three Veneroida species are the same as 2 n = 38. The karyotype of Solen grandis is 26m + 6sm + 2st + 4t, NF = 70, the karyotype of Saxidomus purpuratus is 32m + 2sm + 4st/t, NF = 72, and the karyotype of Mactra chinensis is 20m + 16sm + 2st/t, NF = 74. Satellite and sex chromosome were not found among the chromosomes of three species.

  2. Application of chemometric studies to metal concentrations in molluscs from the Strait of Magellan (Chile).

    Science.gov (United States)

    España, M S Astorga; Rodríguez, E M Rodríguez; Romero, C Díaz

    2007-05-01

    Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Se, Ni, and Cd concentrations were determined in 126 mollusc samples belonging to five different species (Mytilus chilensis, n = 47; Nacella deaurata, n = 65; Aulacomya ater, n = 4; Fissurella picta, n = 4; Acanthina monodon, n = 6) collected from the coasts of the Strait of Magellan. The metals analysed presented significant differences between the mean concentrations for the mollusc species considered. Factor and discriminant analyses made possible the differentiation of the mollusc species. In addition, when discriminant analysis was used, good classifications were obtained according to sampling zone and weight-to-length ratio of the organisms. PMID:17375348

  3. Interspecific hybridization between Crassostrea angulata and C. ariakensis

    Science.gov (United States)

    Yao, Tuo; Zhang, Yuehuan; Yan, Xiwu; Wang, Zhaoping; Li, Dongchun; Su, Jiaqi; Yu, Ruihai

    2015-08-01

    Interspecific hybridization can generate heterosis, which is proven to be a useful tool in selective breeding programs for oyster culture. Crassostrea angulata and C. ariakensis are two important economic shellfish species in China. We conducted 2 × 2 reciprocal crosses to determine whether these two species can cross-fertilize and their hybrids can hatch, survive and perform heterosis. Fertilization was found symmetrical without delay. The rate of fertilization success of C. angulata ♀ × C. ariakensis ♂ was lower than that of C. ariakensis ♀ × C. angulata ♂, and the success rate of both hybridizations was lower than that of two intraspecific crosses each. During the planktonic period, survival rate of the progeny was lower in the hybrid crosses than in the intraspecific crosses. On day 360, mean shell height of the progeny of C. angulata ♀ × C. angulata ♂ was highest, which was followed by that of C. angulata ♀ × C. ariakensis ♂, C. ariakensis ♀ × C. ariakensis ♂ and C. ariakensis ♀ × C. angulata ♂ in a descending order. Morphology of adults produced by the hybrid crosses was similar to that of C. angulata. Both hybrids underwent normal gonad development and produced mature gametes in the mating season. This study provided new insights into the quantitative traits in interspecific crosses of Crassostrea species, thus being of guidance value for selective breeding of oyster.

  4. The reproductive cycle of the oyster Crassostrea gasar.

    Science.gov (United States)

    Gomes, C H A M; Silva, F C; Lopes, G R; Melo, C M R

    2014-11-01

    The purpose of this study was to analyze the reproductive cycle of the oyster Crassostrea gasar (= C. brasiliana) in the field and the laboratory. The reproductive cycle of the animals was evaluated in the field at Sambaqui Beach, Florianópolis, SC (27° 29'18″ S and 48° 32'12″ W) from May 2008 through November 2009. In July, the animals were in the resting stage. The early growth stage began in August and was followed by the late growth stage in October. In November and December, the oysters began to enter the mature stage. Females in spawning condition were predominant during these months. The stages of the reproductive cycle were positively associated with temperature (r=0.77, Preproductive development of Crassostrea gasar. The condition index (CI) of the animals was also associated with the seawater temperature. The highest values of the condition index were observed during the months when the temperature of the seawater was gradually increasing. A laboratory experiment was performed to test the effect of salinity on the reproductive cycle of the oysters. The experiment was conducted in standardized tanks. The animals were conditioned using two salinities (24‰ and 34‰). The salinity regime influenced the development of the gonadal tissue of the oysters. A salinity of 24‰ produced greater reproductive development. PMID:25627610

  5. Marine molluscs in environmental monitoring. I. Cellular and molecular responses

    Science.gov (United States)

    Bresler, Vladimir; Abelson, Avigdor; Fishelson, Lev; Feldstein, Tamar; Rosenfeld, Michael; Mokady, Ofer

    2003-10-01

    The study reported here is part of an ongoing effort to establish sensitive and reliable biomonitoring markers for probing the coastal marine environment. Here, we report comparative measurements of a range of histological, cellular and sub-cellular parameters in molluscs sampled in polluted and reference sites along the Mediterranean coast of Israel and in the northern tip of the Gulf of Aqaba, Red Sea. Available species enabled an examination of conditions in two environmental 'compartments': benthic (Donax trunculus) and intertidal (Brachidontes pharaonis, Patella caerulea) in the Mediterranean; pelagic (Pteria aegyptia) and intertidal (Cellana rota) in the Red Sea. The methodology used provides rapid results by combining specialized fluorescent probes and contact microscopy, by which all parameters are measured in unprocessed animal tissue. The research focused on three interconnected levels. First, antixenobiotic defence mechanisms aimed at keeping hazardous agents outside the cell. Paracellular permeability was 70-100% higher in polluted sites, and membrane pumps (MXRtr and SATOA) activity was up to 65% higher in polluted compared to reference sites. Second, intracellular defence mechanisms that act to minimize potential damage by agents having penetrated the first line of defence. Metallothionein expression and EROD activity were 160-520% higher in polluted sites, and lysosomal functional activity (as measured by neutral red accumulation) was 25-50% lower. Third, damage caused by agents not sufficiently eliminated by the above mechanisms (e.g. single-stranded DNA breaks, chromosome damage and other pathological alterations). At this level, the most striking differences were observed in the rate of micronuclei formation and DNA breaks (up to 150% and 400% higher in polluted sites, respectively). The different mollusc species used feature very similar trends between polluted and reference sites in all measured parameters. Concentrating on relatively basic

  6. PARASITIC AND SYMBIONIC FAUNA IN OYSTERS (CRASSOSTREA VIRGINICA) COLLECTED FROM THE CALOOSAHATCHEE RIVER AND ESTUARY, FLORIDA

    Science.gov (United States)

    Studies of oysters, Crassostrea virginica, collected from ten sites in the Caloosahatchee River and Estuary, Florida, revealed a varied parasite and symbiotic fauna that have never been reported from this area. Organisms observed included ovacystis virus infecting gametes...

  7. Response of Metallothionein biomarker in oyster Crassostrea sp. to the mercury and cadmium gradient

    Directory of Open Access Journals (Sweden)

    A. Azimi

    2014-05-01

    Conclusion: MT protein in oyster Crassostrea sp. can be considered as a suitable biomarker of Cd contamination in body and environment. Hence, it could be used for assessing and monitoring ecosystems.

  8. Měkkýši zrušené Státní přírodní rezervace Loucké rybníky (Slezsko, Česká republika Molluscs of the abolished reserve of the Loucké Rybníky ponds (Silesia, Czech Republic

    Directory of Open Access Journals (Sweden)

    Jiří Kupka

    2011-11-01

    Full Text Available The Loucké Rybníky ponds State Nature Reserve was established in 1954 and due to negative effects of mining activities it was abolished in 1979. This article presents results of malacological survey in the Loucké Rybníky ponds (Karviná-Louky, Czech Republic conducted in 2006 and 2007. The samples were collected at seven locations which match with sites sampled in 1954 and 1978; the location of sites were detected based on original schematic maps showing their position. The research was focused on aquatic species, terrestrial mollusc were collected only marginally. In 2006 and 2007, 38 mollusc species were found (35 gastropods and 3 bivalves, which include 17 species of aquatic molluscs and 21 terrestrial. Based on comparison with the data collected in 1954 and 1978 we conclude that the total destruction of aquatic habitats was irreversible and lead to changes in the species composition. Several rare and endangered species have extinct at this site and the total species richness of aquatic species decided from 29 to 17.

  9. Genetic improvement of hatchery propagated bivalve stocks : prospects and constraints

    OpenAIRE

    Boudry, Pierre

    2005-01-01

    To date, the most significant genetic improvement for the production of Pacific oyster (Crassostrea gigas) has been obtained through the production of triploids, especially since the development of tetraploids. Quantitative genetics studies suggest that significant gains, for disease resistance or other traits, could be obtained in diploids. However, the limited extent of hatchery-propagation (versus natural recruitment) and/or various technical difficulties and biological characteristics of ...

  10. Polychlorinated biphenyls, organochlorine pesticides and trace metals in cultured and harvested bivalves from the eastern Adriatic coast (Croatia).

    Science.gov (United States)

    Milun, Vesna; Lušić, Jelena; Despalatović, Marija

    2016-06-01

    Polychlorinated biphenyls, organochlorine pesticides and trace metals were determined in tissues of bivalve molluscs (Mytilus galloprovincialis, Ostrea edulis, Venus verrucosa, Arca noae and Callista chione), collected from 11 harvesting and 2 cultured locations along the eastern Adriatic coast, in May and November 2012. Concentrations (ng g(-1) dry weight) of organochlorines ranged from 1.53 to 21.1 for PCBs and 0.68 to 5.21 for p,p'-DDTs. HCB, lindane, heptachlor and aldrin-like compounds were found in lower levels or were not detected. Metal concentrations (mg kg(-1) dry weight) ranged from 0.23 to 4.03 for Cd, 0.87-3.43 for Cr, 3.69-202.3 for Cu, 0.06-0.26 for HgT, 0.62-9.42 for Ni, 0.95-4.64 for Pb, and 55.76-4010.3 for Zn. Established organochlorine and trace metal levels were lower than the maximum allowable levels in seafood set by the European Commission. PMID:27010163

  11. Molecular identification, phylogeny and geographic distribution of Brazilian mangrove oysters (Crassostrea

    Directory of Open Access Journals (Sweden)

    Aline Grasielle Costa de Melo

    2010-01-01

    Full Text Available Oysters (Ostreidae manifest a high degree of phenotypic plasticity, whereby morphology is of limited value for species identification and taxonomy. By using molecular data, the aim was to genetically characterize the species of Crassostrea occurring along the Brazilian coast, and phylogenetically relate these to other Crassostrea from different parts of the world. Sequencing of the partial cytochrome oxidase c subunit I gene (COI, revealed a total of three species of Crassostrea at 16 locations along the Brazilian coast. C. gasar was found from Curuçá (Pará state to Santos (São Paulo state, and C. rhizophorae from Fortim (Ceará state to Florianópolis (Santa Catarina state, although small individuals of the latter species were also found at Ajuruteua beach (municipality of Bragança, Pará state. An unidentified Crassostrea species was found only on Canela Island, Bragança. Crassostrea gasar and C. rhizophorae grouped with C. virginica, thereby forming a monophyletic Atlantic group, whereas Crassostrea sp. from Canela Island was shown to be more similar to Indo-Pacific oysters, and either arrived in the Atlantic Ocean before the convergence of the Isthmus of Panama or was accidentally brought to Brazil by ship.

  12. Concentration peculiarities of radionuclides by freshwater molluscs of Chernobyl NPP exclusion zone

    International Nuclear Information System (INIS)

    The results of radionuclides 90Sr and 137Cs content in molluscs tissue of water objects within Chernobyl NPP exclusion zone has been analysed. The age dynamics of radionuclides content in some species of Gastropoda was studied

  13. The use of yolk protein as biomarkers for endocrine disruption in molluscs

    DEFF Research Database (Denmark)

    Holbech, Henrik; Kinnberg, Karin Lund; Bjerregaard, Poul;

    of standardized tests in molluscs is that no specific biomarkers or endpoints for endocrine effects have been validated. Some attempts have been made to transfer biomarkers developed for vertebrates – e.g. from fish to molluscs to investigate ED effects. One example is the vertebrate yolk protein...... vitellogenin that is known to be oestrogen dependent in fish. The yolk proteins in molluscs have been proposed to have the same oestrogenic dependence and used as biomarker for oestrogenic EDs. The present work investigates the possible usability of the main yolk protein in three species of molluscs to...... quantify the concentration of the yolk protein in juveniles and adult male and female U. pictorum and U. tumidus and in the hermaphroditic L. stagnalis. With use of immune-histology, the distribution of the proteins in the tissue of the three species was investigated. The ELISAs revealed that the normal...

  14. Fish and bivalves at Bolsa Chica Marsh re-establishment project; Progress report III

    OpenAIRE

    Knaggs, Eric H.; Mall, Rolf E.

    1980-01-01

    The objectives of our fish and bivalve study are: 1. Determine changes in the number of species of fish and bivalves before Phase I and during Phase 1 at Bolsa Chica Marsh. 2. Determine if California Department of Fish and Game's predicted benefits in Phase I were achieved by increases in fish species. 3. Determine influences of water management practices upon fish and bivalve composition. Thirteen species of fish and five species of bivalves were collected from ...

  15. An examination of the ingestion, bioaccumulation, and depuration of titanium dioxide nanoparticles by the blue mussel (Mytilus edulis) and the eastern oyster (Crassostrea virginica).

    Science.gov (United States)

    Doyle, John J; Ward, J Evan; Mason, Robert

    2015-09-01

    The production rates of titanium dioxide (TiO2) nanoparticles for consumer products far exceed the pace at which research can determine the effects of these particles in the natural environment. Sedentary organisms such as suspension-feeding bivalves are particularly vulnerable to anthropogenic contaminants, such as nanoparticles, that enter coastal environments. The purpose of this work was to examine the ingestion, bioaccumulation, and depuration rates of TiO2 nanoparticles by two species of suspension-feeding bivalves, the blue mussel (Mytilus edulis) and the eastern oyster (Crassostrea virginica). Two representative TiO2 nanoparticles, UV-Titan M212 (Titan) and Aeroxide P25 (P25), were delivered to the animals either incorporated into marine snow or added directly to seawater at a concentration of 1.0 mg/L for exposure periods of 2 and 6 h. After feeding, the animals were transferred to filtered-seawater and allowed to depurate. Feces and tissues were collected at 0, 12, 24, 72, and 120 h, post-exposure, and analyzed for concentrations of titanium by inductively coupled plasma-mass spectrometry. Results indicated that the capture and ingestion (i.e., transfer to the gut) of TiO2 nanoparticles by both mussels and oysters was not dependent on the presence of marine snow, and weight-standardized clearance rates of bivalves exposed to TiO2 nanoparticles were not significantly different than those of unexposed control animals. Both species ingested about half of the nanoparticles to which they were exposed, and >90% of the nanoparticles were egested in feces within 12 h, post-exposure. The findings of this study demonstrate that mussels and oysters can readily ingest both Titan and P25 nanoparticles regardless of the form in which they are encountered, but depurate these materials over a short period of time. Importantly, bioaccumulation of Titan and P25 nanoparticles does not occur in mussels and oysters following exposures of up to 6 h. PMID:26263835

  16. Gills as a glutathione-dependent metabolic barrier in Pacific oysters Crassostrea gigas: Absorption, metabolism and excretion of a model electrophile.

    Science.gov (United States)

    Trevisan, Rafael; Mello, Danielle F; Delapedra, Gabriel; Silva, Danilo G H; Arl, Miriam; Danielli, Naissa M; Metian, Marc; Almeida, Eduardo A; Dafre, Alcir L

    2016-04-01

    The mercapturic acid pathway (MAP) is a major phase II detoxification route, comprising the conjugation of electrophilic substances to glutathione (GSH) in a reaction catalyzed by glutathione S-transferase (GST) enzymes. In mammals, GSH-conjugates are exported from cells, and the GSH-constituent amino acids (Glu/Gly) are subsequently removed by ectopeptidases. The resulting Cys-conjugates are reabsorbed and, finally, a mercapturic acid is generated through N-acetylation. This pathway, though very well characterized in mammals, is poorly studied in non-mammalian biological models, such as bivalve mollusks, which are key organisms in aquatic ecosystems, aquaculture activities and environmental studies. In the present work, the compound 1-chloro-2,4-dinitrobenzene (CDNB) was used as a model electrophile to study the MAP in Pacific oysters Crassostrea gigas. Animals were exposed to 10μM CDNB and MAP metabolites were followed over 24h in the seawater and in oyster tissues (gills, digestive gland and hemolymph). A rapid decay was detected for CDNB in the seawater (half-life 1.7h), and MAP metabolites peaked in oyster tissues as soon as 15min for the GSH-conjugate, 1h for the Cys-conjugate, and 4h for the final metabolite (mercapturic acid). Biokinetic modeling of the MAP supports the fast CDNB uptake and metabolism, and indicated that while gills are a key organ for absorption, initial biotransformation, and likely metabolite excretion, hemolymph is a possible milieu for metabolite transport along different tissues. CDNB-induced GSH depletion (4h) was followed by increased GST activity (24h) in the gills, but not in the digestive gland. Furthermore, the transcript levels of glutamate-cysteine ligase, coding for the rate limiting enzyme in GSH synthesis, and two phase II biotransformation genes (GSTpi and GSTo), presented a fast (4h) and robust (∼6-70 fold) increase in the gills. Waterborne exposure to electrophilic compounds affected gills, but not digestive gland

  17. An Efficient Method for Genomic DNA Extraction from Different Molluscs Species

    OpenAIRE

    Henrique Guedes-Pinto; Alexandra Leitão; Raquel Chaves; Estela Bastos; Jorge C. Pereira

    2011-01-01

    The selection of a DNA extraction method is a critical step when subsequent analysis depends on the DNA quality and quantity. Unlike mammals, for which several capable DNA extraction methods have been developed, for molluscs the availability of optimized genomic DNA extraction protocols is clearly insufficient. Several aspects such as animal physiology, the type (e.g., adductor muscle or gills) or quantity of tissue, can explain the lack of efficiency (quality and yield) in molluscs genomic D...

  18. Three-dimensional morphometric ontogeny of mollusc shells by micro-computed tomography and geometric analysis

    OpenAIRE

    Monnet, C; Zollikofer, C; Bucher, H.; Goudemand, N.

    2009-01-01

    As one of the essential components of the fossil record, shells of molluscs provide crucial data for taxonomic, phylogenetic or evolutionary studies. The mollusc shell has often very few discrete morphological characters, and its most important character is its three-dimensional (3-D) geometry, which is well diversified, continuous and highly integrated. However, standard morphometric methods remain mostly two-dimensional (2-D) and do not account for the ontogenetic changes of the shell, whic...

  19. Modeling the carbon isotope composition of bivalve shells (Invited)

    Science.gov (United States)

    Romanek, C.

    2010-12-01

    The stable carbon isotope composition of bivalve shells is a valuable archive of paleobiological and paleoenvironmental information. Previous work has shown that the carbon isotope composition of the shell is related to the carbon isotope composition of dissolved inorganic carbon (DIC) in the ambient water in which a bivalve lives, as well as metabolic carbon derived from bivalve respiration. The contribution of metabolic carbon varies among organisms, but it is generally thought to be relatively low (e.g., 90%) in the shells from terrestrial organisms. Because metabolic carbon contains significantly more C-12 than DIC, negative excursions from the expected environmental (DIC) signal are interpreted to reflect an increased contribution of metabolic carbon in the shell. This observation contrasts sharply with modeled carbon isotope compositions for shell layers deposited from the inner extrapallial fluid (EPF). Previous studies have shown that growth lines within the inner shell layer of bivalves are produced during periods of anaerobiosis when acidic metabolic byproducts (e.g., succinic acid) are neutralized (or buffered) by shell dissolution. This requires the pH of EPF to decrease below ambient levels (~7.5) until a state of undersaturation is achieved that promotes shell dissolution. This condition may occur when aquatic bivalves are subjected to external stressors originating from ecological (predation) or environmental (exposure to atm; low dissolved oxygen; contaminant release) pressures; normal physiological processes will restore the pH of EPF when the pressure is removed. As a consequence of this process, a temporal window should also exist in EPF at relatively low pH where shell carbonate is deposited at a reduced saturation state and precipitation rate. For example, EPF chemistry should remain slightly supersaturated with respect to aragonite given a drop of one pH unit (6.5), but under closed conditions, equilibrium carbon isotope fractionation

  20. Artificially evolved functional shell morphology of burrowing bivalves

    DEFF Research Database (Denmark)

    Germann, D. P.; Schatz, W.; Hotz, Peter Eggenberger

    2014-01-01

    dimensional (3D) objects, the first ever artificial evolution of a physical bivalve shell was performed. The result was a vertically flattened shell occupying only the top sediment layers. Insufficient control of the sediment was the major limitation of the setup and restricted the significance of the results......, there are almost no studies experimentally testing their dynamic properties. To investigate the functional morphology of the bivalve shell, we employed a synthetic methodology and built an experimental setup to simulate the burrowing process. Using an evolutionary algorithm and a printer that prints three...

  1. Influence of food supply on the δ13C signature of mollusc shells: implications for palaeoenvironmental reconstitutions

    Science.gov (United States)

    Lartaud, Franck; Emmanuel, Laurent; de Rafelis, Marc; Pouvreau, Stephane; Renard, Maurice

    2010-02-01

    Compared to oxygen isotopes, the carbon isotope composition of biogenic carbonates is less commonly used as proxy for palaeoenvironmental reconstructions because shell δ13C is derived from both dissolved inorganic (seawater) and organic carbon sources (food), and interactions between these two pools make it difficult to unambiguously identify any independent effect of either. The main purpose of this study was to demonstrate any direct impact of variable food supply on bivalve shell δ13C signatures, using low/high rations of a 13C-light mixed algal diet fed to 14-month-old (adult) cultured Japanese Crassostrea gigas under otherwise essentially identical in vitro conditions during 3 summer months (May, June and July 2003, seawater temperature means at 16, 18 and 20 °C respectively) in experimental tanks at the Argenton laboratory along the Brittany Atlantic coast of France. At a daily ration of 12% (versus 4%) oyster dry weight, the newly grown part of the shells (hinge region) showed significantly lower δ13C values, by 3.5‰ (high ration: mean of -5.8 ± 1.1‰, n = 10; low ration: mean of -2.3 ± 0.7‰, n = 6; ANOVA Scheffe's test, p oysters from Marennes-Ol éron Bay in the study region, which is not inconsistent with an independent influence of diet type. Although there was no significant difference between the two food regimes in terms of δ18O shell values (means of 0.1 ± 0.3 and 0.4 ± 0.2‰ at high and low rations respectively, non-significant Scheffe's test), a positive δ13C vs. δ18O relationship recorded at high rations supports the interpretation of a progressive temperature-mediated rise in metabolic activity fuelled by higher food supply (in this case reflecting increased energy investment in reproduction), in terms not only of δ13C (metabolic signal) but also of δ18O (seawater temperature signal). Overall, whole-shell δ18O trends faithfully recorded summer/winter variations in seawater temperature experienced by the 17-month-old cultured

  2. Adult Pacific Oyster (Crassostrea gigas) May Have Light Sensitivity.

    Science.gov (United States)

    Wu, Changlu; Wang, Jiao; Yang, Yanjian; Li, Zhuang; Guo, Ting; Li, Yongchuan; Wang, Xiaotong

    2015-01-01

    Light-sensitivity is an important aspect of mollusk survival as it plays a vital role in reproduction and predator avoidance. In the Pacific oyster Crassostrea gigas light sensitivity has been demonstrated in the larval stage but has not yet been conclusively demonstrated in adult oysters. In this paper we describe an experiment which was undertaken to determine if adult Pacific oysters were sensitive to light. One LED flashlight was used to shine light onto adult oysters while they were filtering seawater through their shell openings. We found that the degree of opening increased gradually during the light period but rapidly decreased when the flashlight was turned off in the treated group but not in the control group. These results suggest that adult Pacific oyster may be sensitive to light. PMID:26474058

  3. Proton microprobe studies of fluorine distributions in mollusc shells

    Science.gov (United States)

    Coote, G. E.; Trompetter, W. J.

    1995-09-01

    Since the mineral in mollusc shells, calcium carbonate, has no site in the crystal for a fluorine ion we would expect this element to occur as only a trace element in shells. Our measurements have revealed something quite different: in seven of eight species we found in both aragonite and calcite shells some growth layers with concentrations as high as 150 ppm by weight, and in a common species of oyster layers about 0.15 mm wide with up to 1700 ppm; this is more than occurs in human tooth enamel, whose apatite has an affinity for fluorine ions. The overall pattern of fluorine was quite different to that of the other minor element strontium, although in several species peaks in the two distributions occurred in exactly the same layers, showing that they had a common cause. The highest fluorine concentration is usually found near the outer surface of the oldest part of the shell, but the evidence suggests that it was deposited during calcification and did not diffuse in aftewards from seawater; for example in the youngest parts of the shell the distribution is several times broader. Two species of oyster (with calcite shells) showed completely different fluorine patterns: the flat oyster Tiostrea had a constant level of about 30 ppm, whereas the Pacific oyster Crassotreh gigas revealed isolated narrow layers with concentrations as high as 1700 ppm. These two species have quite different reproductive behaviour and it is possible that Sr and F markings are formed during the spawning period.

  4. Phyletic patterns of early development in gastropod molluscs.

    Science.gov (United States)

    Lindberg, David R; Guralnick, Robert P

    2003-01-01

    Cell lineage data for 30 exemplar gastropod taxa representing all major subclades and the outgroup Polyplacophora were examined for phylogenetic signal using cladistic analysis. Most cell lineages show phyletic trends of acceleration or retardation relative to the outgroup and more basal ingroup taxa, and when coded this variation is phylo-genetically informative. PAUP analyses of a cell lineage data set under three sets of character ordering assumptions produced similar tree topologies. The topologies of the strict consensus trees for both ordered and Dollo (near irreversibility of character transformations) character assumptions were similar, whereas the unordered character assumption recovers the least phyletic information. The cell lineage cladograms are also in agreement with the fossil record of the timing and sequence of gastropod subclade origination. A long branch lies between the Patellogastropoda+Vetigastropoda grade and the Neritopsina+Apogastropoda clade. The geological timing of this long branch is correlated with the first large-scale terrestrially derived eutrophication of the near-shore marine habitat, and one possible explanation for this branch may be a developmental shift associated with the evolution of feeding larvae in response to the more productive conditions in the near-shore water column. Although character transformations are highly ordered in this data set, developmental rate characters (like all other morphological and molecular characters) are also subject to homoplasy. Finally, this study further supports the hypothesis that early development of gastropod molluscs has conserved a strong phyletic signal for about half a billion years. PMID:12950628

  5. Roles of extracellular ions and pH in 5-HT-induced sperm motility in marine bivalve.

    Science.gov (United States)

    Alavi, Sayyed Mohammad Hadi; Matsumura, Natsuki; Shiba, Kogiku; Itoh, Naoki; Takahashi, Keisuke G; Inaba, Kazuo; Osada, Makoto

    2014-03-01

    Factors that inhibit and stimulate the initiation of sperm motility were determined for Manila clam (Ruditapes philippinarum), Pacific oyster (Crassostrea gigas), and Japanese scallop (Patinopecten yessoensis). Compared with artificial seawater (ASW), serotonin (5-hydroxytryptamine creatinine sulfate, 5-HT) could fully trigger sperm motility and increase sperm velocity and motility duration. Sperm motility was decreased in ASW at pH 6.5-7.0 and suppressed at pH 4.0. In Manila clam and Pacific oyster, 5-HT could overcome the inhibitory effects of acidic pH on sperm motility. In the presence of nigericin (a K(+)/H(+) exchanger), sperm motility was only triggered at pH 8.3. Testicular fluid K(+) concentrations were two- to fourfold higher than that in ASW. Sperm motility and velocity were decreased in ASW or 5-HT containing ≥40  mM K(+) or ≥2.5  mM 4-aminopyridine, suggesting K(+) efflux requirement to initiate motility. Sperm motility and velocity were reduced in ASW or 5-HT containing EGTA or W-7, suggesting that extracellular Ca(2)(+) is required for Ca(2)(+)/calmodulin-dependent flagellar beating. Ca(2)(+) influx occurs via Ca(2)(+) channels because sperm motility and velocity were decreased in both ASW and 5-HT containing T-type and L-type Ca(2)(+) channel blockers. 5-HT-dependent initiation of sperm motility was associated with intracellular Ca(2)(+) rise, which was comparable to that seen in ASW but was not observed in the presence of EGTA or a Ca(2)(+) channel blocker. Extracellular Na(+) is also essential for sperm motility initiation via regulation of Na(+)/Ca(2)(+) exchange. Overall, 5-HT-dependent initiation of sperm motility in marine bivalve mollusks is an osmolality-independent mechanism and regulated by extracellular pH, K(+), Ca(2)(+), and Na(+). PMID:24398874

  6. Genetic inviability is a major driver of type III survivorship in experimental families of a highly fecund marine bivalve.

    Science.gov (United States)

    Plough, L V; Shin, G; Hedgecock, D

    2016-02-01

    The offspring of most highly fecund marine fish and shellfish suffer substantial mortality early in the life cycle, complicating prediction of recruitment and fisheries management. Early mortality has long been attributed to environmental factors and almost never to genetic sources. Previous work on a variety of marine bivalve species uncovered substantial genetic inviability among the offspring of inbred crosses, suggesting a large load of early-acting deleterious recessive mutations. However, genetic inviability of randomly bred offspring has not been addressed. Here, genome-wide surveys reveal widespread, genotype-dependent mortality in randomly bred, full-sib progenies of wild-caught Pacific oysters (Crassostrea gigas). Using gene-mapping methods, we infer that 11-19 detrimental alleles per family render 97.9-99.8% of progeny inviable. The variable genomic positions of viability loci among families imply a surprisingly large load of partially dominant or additive detrimental mutations in wild adult oysters. Although caution is required in interpreting the relevance of experimental results for natural field environments, we argue that the observed genetic inviability corresponds with type III survivorship, which is characteristic of both hatchery and field environments and that our results, therefore, suggest the need for additional experiments under the near-natural conditions of mesocosms. We explore the population genetic implications of our results, calculating a detrimental mutation rate that is comparable to that estimated for conifers and other highly fecund perennial plants. Genetic inviability ought to be considered as a potential major source of low and variable recruitment in highly fecund marine animals. PMID:26756438

  7. Lower Carboniferous marine bivalves from the Cantabrian Mountains (Spain)

    NARCIS (Netherlands)

    Amler, M.R.W.; Winkler Prins, C.F.

    1999-01-01

    The Lower Carboniferous bivalves of the Vegamián and Genicera formations are described, followed by a brief discussion on palaeoenvironmental and palaeogeographical aspects. The black shales of the Vegamián Fm. (Tournaisian) yield a peculiar association of euchondriid taxa (Euchondria wagneri sp. no

  8. Molecular approaches to bivalve population studies: a review

    Directory of Open Access Journals (Sweden)

    Dragomir-Cosmin David

    2011-12-01

    Full Text Available This paper presents a literature review concerning the importance of molecular approaches in bivalve’s population study. The class Bivalvia counts more than 20,000 species with a wide distribution both in freshwater and marine environment. Given their importance especially in aquaculture as a source of food, they have also a strong economic impact upon human society. This review encompasses best practices in bivalve studies from field sampling to laboratory analyses, addressing questions about molecular methods and tools commonly used by specialized researchers. Molecular tools specifically deals with phylogeography, population genetics, biology, ecology and taxonomy. In all these fields, molecular markers play an important role by completing some unanswered questions such as the role of the bivalves in the ecosystems in relation to anthropogenic and global change issues. Numerous genetic markers were developed for specific problems, thereferore we identify as a major issue the absence of uniform and universally recognized methods. The various sections of the paper emphasize from peer reviewed literature literature which are considered the most useful markers, costs and benefits of different methodology, major gaps of knowledge.in bivalve population studies. By reviewing virtually all genetic markers employed during nearly half a century of bivalve molecular research, in our opinion two are the best option “tools: the mitochondrial COI (cytochrome oxidase subunit I and nuclear ITS2 (internal transcribed spacer 2.

  9. Mollusc fauna associated with the Cystoseira algal associations in the Gulf of Trieste (Northern Adriatic Sea

    Directory of Open Access Journals (Sweden)

    V. PITACCO

    2014-07-01

    Full Text Available Mollusc assemblages associated with Cystoseira associations were sampled in the southern part of the Gulf of Trieste during the summers of 2008 and 2012. Samples were collected by SCUBA diving in the infralittoral belt (from 1 to 4 m depth. The surface within frames of 20 x 20 cm was scraped off with samples were collected by hand or with an air-lift sampler. Four erected algal species were found: Cystoseira barbata, C. compressa, C. corniculata and Halopithys incurva. A total of 69 species of molluscs were identified in those associations. Gastropoda were dominant, with the highest species richness and abundance, followed by Bivalvia and Polyplacophora. A large number of juveniles were found, proving the importance of Cystoseira associations for mollusc recruitment. Differences in composition, structure and abundance of mollusc assemblages were found for sites dominated by different algal species, and correspond to different morphology and degree of development of canopy-forming species. The present study confirms that the dominant algal species within Cystoseira associations strongly influence, although at different levels, abundance and distribution of mollusc assemblages in the Northern Adriatic Sea.

  10. Chemical composition of inks of diverse marine molluscs suggests convergent chemical defenses.

    Science.gov (United States)

    Derby, Charles D; Kicklighter, Cynthia E; Johnson, P M; Zhang, Xu

    2007-05-01

    Some marine molluscs, notably sea hares, cuttlefish, squid, and octopus, release ink when attacked by predators. The sea hare Aplysia californica releases secretions from the ink gland and opaline gland that protect individuals from injury or death from predatory spiny lobsters through a combination of mechanisms that include chemical deterrence, sensory disruption, and phagomimicry. The latter two mechanisms are facilitated by millimolar concentrations of free amino acids (FAA) in sea hare ink and opaline, which stimulate the chemosensory systems of predators, ultimately leading to escape by sea hares. We hypothesize that other inking molluscs use sensory disruption and/or phagomimicry as a chemical defense. To investigate this, we examined concentrations of 21 FAA and ammonium in the defensive secretions of nine species of inking molluscs: three sea hares (Aplysia californica, Aplysia dactylomela, Aplysia juliana) and six cephalopods (cuttlefish: Sepia officinalis; squid: Loligo pealei, Lolliguncula brevis, Dosidicus gigas; octopus: Octopus vulgaris, Octopus bimaculoides). We found millimolar levels of total FAA and ammonium in these secretions, and the FAA in highest concentration were taurine, aspartic acid, glutamic acid, alanine, and lysine. Crustaceans and fish, which are major predators of these molluscs, have specific receptor systems for these FAA. Our chemical analysis supports the hypothesis that inking molluscs have the potential to use sensory disruption and/or phagomimicry as a chemical defense. PMID:17393278

  11. Identification of North Sea molluscs with DNA barcoding.

    Science.gov (United States)

    Barco, Andrea; Raupach, Michael J; Laakmann, Silke; Neumann, Hermann; Knebelsberger, Thomas

    2016-01-01

    Sequence-based specimen identification, known as DNA barcoding, is a common method complementing traditional morphology-based taxonomic assignments. The fundamental resource in DNA barcoding is the availability of a taxonomically reliable sequence database to use as a reference for sequence comparisons. Here, we provide a reference library including 579 sequences of the mitochondrial cytochrome c oxidase subunit I for 113 North Sea mollusc species. We tested the efficacy of this library by simulating a sequence-based specimen identification scenario using Best Match, Best Close Match (BCM) and All Species Barcode (ASB) criteria with three different threshold values. Each identification result was compared with our prior morphology-based taxonomic assignments. Our simulation resulted in 87.7% congruent identifications (93.8% when excluding singletons). The highest number of congruent identifications was obtained with BCM and ASB and a 0.05 threshold. We also compared identifications with genetic clustering (Barcode Index Numbers, BINs) computed by the Barcode of Life Datasystem (BOLD). About 68% of our morphological identifications were congruent with BINs created by BOLD. Forty-nine sequences were clustered in 16 discordant BINs, and these were divided in two classes: sequences from different species clustered in a single BIN and conspecific sequences divided in more BINs. Whereas former incongruences were probably caused by BOLD entries in need of a taxonomic update, the latter incongruences regarded taxa requiring further investigations. These include species with amphi-Atlantic distribution, whose genetic structure should be evaluated over their entire range to produce a reliable sequence-based identification system. PMID:26095230

  12. An integrated study of endocrine disruptors in sediments and reproduction-related parameters in bivalve molluscs from the Biosphere's Reserve of Urdaibai (Bay of Biscay).

    Science.gov (United States)

    Puy-Azurmendi, Eunate; Ortiz-Zarragoitia, Maren; Kuster, Marina; Martínez, Elena; Guillamón, Míriam; Domínguez, Carmen; Serrano, Teresa; Barbero, Mari Carmen; Alda, Miren López de; Bayona, Josep M; Barceló, Damiá; Cajaraville, Miren P

    2010-01-01

    Urdaibai was declared a Biosphere's Reserve by UNESCO in 1984. Because we observed a high prevalence of hermaphroditism in mussels sampled in Urdaibai in March 2004, we started the present research work in order to determine the presence of endocrine disruptors (EDs) in sediments and to study possible EDs effects on mussels and oysters using gonad index and vitellogenin (VTG)-like protein levels as biomarkers. Samples were collected at five localities in April 2007 and 2008, and in October 2007. Estrogenic hormones were not detected in sediments and levels of bisphenol A and organotin compounds were very low. Alkylphenols were found at moderate levels and showed a time-dependent decrease. Phthalates were found at levels up to 8000 ng/g. High prevalence of oocyte atresia and necrosis occurred in mussels sampled in April. Retarded gametogenesis was observed in an oyster population from a shipyard. Hermaphrodites or alterations in VTG-like protein levels were not found but the high prevalence of histopathological alterations in oocytes is of concern. PMID:19913907

  13. Glycoconjugate histochemistry and nNOS immunolocalization in the mantle and foot epithelia of Tapes philippinarum (bivalve mollusc

    Directory of Open Access Journals (Sweden)

    Aurelio Licata

    2011-08-01

    Full Text Available Glycosaminoglycans and NO synthase probably regulate mucous cell secretion in the skin of Tapes philippinarum. We have demonstrated the presence of "protein" cells, "glycogen" cells, "phenol" cells and five types of mucous cells, with different chemical composition of the mucus in the mantle epithelium of T. philippinarum. The foot epithelium contained "protein" cells and two types of mucous cells. Using biotinylated lectins, in the mantle and foot epithelia we have shown specific sites for the following oligosaccharides: α-D-glucose, α-D-mannose, α-L-fucose, α-D-1,3-N-acetyl-galactosamine and α-N-acetyl-glucosamine. nNOS immunoreactivity in the intraepithelial and intradermal cells and in the mucocytes suggested a regulatory role of NO in mucus secretion, as demonstrated also in other invertebrates.

  14. Gal/GalNAc specific multiple lectins in marine bivalve Anadara granosa.

    Science.gov (United States)

    Adhya, Mausumi; Singha, Biswajit

    2016-03-01

    Complete lectin mapping of molluscs with their diversified recognition pattern and possible role in lectin-carbohydrate interaction based immune response triggering need much attention. In this communication, Gal/GalNAc specific three lectins AGL-IA (Anadara granosa lectin-IA), AGL-IB (A. granosa lectin-IB) and AGL-IV (A. granosa lectin-IV) and a lectin having hemolytic activity AGL-III (A. granosa lectin-III) were purified from the plasma of A. granosa bivalve by a combination of gel filtration and affinity chromatography. AGL-IA and IB were oligomeric lectins whereas, AGL-III and IV were monomeric. The molecular weight of AGL-IA, IB, III and IV were 375, 260, 45 and 33 kDa respectively. AGL-IA and IV agglutinated both rabbit and pronase treated human erythrocytes, whereas AGL-IB agglutinated only rabbit erythrocytes. AGL-III was found to agglutinate rabbit erythrocytes, however, it caused hemolysis of pronase treated human erythrocytes. The activity of all four lectins was calcium dependent and maximum at a pH range 7-8. Apart from Gal/GalNAc specific, the four lectins showed substantial differences in their carbohydrate recognition pattern. Moreover, there was a difference in the carbohydrate specificity between AGL-III and other three lectins (AGL-IA, AGL-IB and AGL-IV) towards polyvalent glycotope. On the one hand, 'cluster glycoside effect' i.e., an enhancement of the activity of a multivalent ligand, was observed for carbohydrate specificities of AGL-IA, AGL-IB, AGL-IV. On the other hand, the effect of multivalent ligands on the carbohydrate specificity of AGL-III was opposite of cluster glycoside effect. The affinity of AGL-IA, AGL-IB and AGL-IV for ligands can be ranked as follows: glycoproteins > polysaccharide > oligosaccharides and monosaccharides. However, Gal related monosaccharides were the best inhibitors of AGL-III and the inhibitory activity decreased gradually in the following order: monosaccharide > disaccharide > polysaccharide. Thus

  15. An Efficient Method for Genomic DNA Extraction from Different Molluscs Species

    Directory of Open Access Journals (Sweden)

    Henrique Guedes-Pinto

    2011-11-01

    Full Text Available The selection of a DNA extraction method is a critical step when subsequent analysis depends on the DNA quality and quantity. Unlike mammals, for which several capable DNA extraction methods have been developed, for molluscs the availability of optimized genomic DNA extraction protocols is clearly insufficient. Several aspects such as animal physiology, the type (e.g., adductor muscle or gills or quantity of tissue, can explain the lack of efficiency (quality and yield in molluscs genomic DNA extraction procedure. In an attempt to overcome these aspects, this work describes an efficient method for molluscs genomic DNA extraction that was tested in several species from different orders: Veneridae, Ostreidae, Anomiidae, Cardiidae (Bivalvia and Muricidae (Gastropoda, with different weight sample tissues. The isolated DNA was of high molecular weight with high yield and purity, even with reduced quantities of tissue. Moreover, the genomic DNA isolated, demonstrated to be suitable for several downstream molecular techniques, such as PCR sequencing among others.

  16. Development and application of a QuEChERS-based extraction method for the analysis of 55 pesticides in the bivalve Scrobicularia plana by GC-MS/MS.

    Science.gov (United States)

    Cruzeiro, Catarina; Rodrigues-Oliveira, Nádia; Velhote, Susana; Pardal, Miguel Ângelo; Rocha, Eduardo; Rocha, Maria João

    2016-05-01

    A method for quantitative determination of 55 pesticides in a bivalve matrix was established, based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction and using gas chromatography (GC)-ion trap (IT) mass spectrometry (MS/MS). Accomplishing the European SANCO guidelines, this method was validated using 5 g of homogenized soft tissue, allowing the quantification of pesticides at ng/g of wet weight (ww). Quantification limits and recovery rates ranged from 0.33 to 10.3 μg/L and from 78 to 119 %, respectively. As an important mollusc, not only from an ecological perspective but also for food consumption, the peppery furrow shell (Scrobicularia plana) was sampled at three strategical sites (Ria Formosa Lagoon, in the south of Portugal) during 2012-2013, over six campaigns. A total of 2160 animals were pooled by place and sex. No statistical differences were found among sites or between sexes. Forty percent of the sampled pools were above quantification limits, reaching total annual average concentrations of ∑800 ng/g ww. Additionally, 83 % of the selected compounds showed concentrations above the legal limits set by the European Directive 2013/39/EU. In conclusion, the applied method was successful and proved that bivalves were contaminated by the selected pesticides. In future work, this methodology can be used to monitor body burdens and obtain data for predicting impacts in shellfish consumers. Graphical Abstract Resume of pesticides extraction and analyses process from S. plana. PMID:27032408

  17. Characteristic crystal orientation of folia in oyster shell, Crassostrea gigas

    International Nuclear Information System (INIS)

    The thin sheets of calcite, termed folia, that make up much of the shell of an oyster are composed of foliated lath. Folia of the giant Pacific oyster (Crassostrea gigas) were examined using TEM (transmission electron microscopy) and tested using microindentation and nanoindentation techniques. Analysis of the Kikuchi patterns obtained from the folia showed that there are two types (type I and type II) of preferred orientation, with an angle of around 70o between them. Nanoindentation tests showed that the folia exhibit a hardness of about 3 GPa and elastic modulus of about 73 GPa. Microcracks were generated using a microindenter in order to study the fracture mechanisms of the folia. Following on from these investigations, fracture mechanisms are discussed in conjunction with the correlation between preferred orientation and structural characteristics during cracking of the folia. Comparing the morphology and the polymorphism with nacre (also known as mother of pearl), the advantages of the relatively fast crystal growth and less amount of organic matrix in folia may have interesting implications for the development of sophisticated synthetic materials

  18. Characteristic crystal orientation of folia in oyster shell, Crassostrea gigas

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Woo [Department of Chemical and Biomolecular Engineering, Sogang University, Seoul (Korea, Republic of); Kim, Gyeung Ho [Nano-Materials Reserch Center, Korea Institute of Science and Technology, Seoul (Korea, Republic of); Choi, Cheong Song [Department of Chemical and Biomolecular Engineering, Sogang University, Seoul (Korea, Republic of)], E-mail: cschoi@sogang.ac.kr

    2008-03-10

    The thin sheets of calcite, termed folia, that make up much of the shell of an oyster are composed of foliated lath. Folia of the giant Pacific oyster (Crassostrea gigas) were examined using TEM (transmission electron microscopy) and tested using microindentation and nanoindentation techniques. Analysis of the Kikuchi patterns obtained from the folia showed that there are two types (type I and type II) of preferred orientation, with an angle of around 70{sup o} between them. Nanoindentation tests showed that the folia exhibit a hardness of about 3 GPa and elastic modulus of about 73 GPa. Microcracks were generated using a microindenter in order to study the fracture mechanisms of the folia. Following on from these investigations, fracture mechanisms are discussed in conjunction with the correlation between preferred orientation and structural characteristics during cracking of the folia. Comparing the morphology and the polymorphism with nacre (also known as mother of pearl), the advantages of the relatively fast crystal growth and less amount of organic matrix in folia may have interesting implications for the development of sophisticated synthetic materials.

  19. Comparative pathology in bivalves: Aetiological agents and disease processes.

    Science.gov (United States)

    Carella, F; Feist, S W; Bignell, J P; De Vico, G

    2015-10-01

    Comparative pathology as a scientific discipline studies animal diseases in relation to their aetiology, pathogenesis and prognosis. Among the main aspects of this discipline, regressive changes, host defense responses with pathological implications and progressive changes, represent the majority of the possible responses of cells and tissues to pathogens and exposure to chemicals. One of the most persistent issues in the field of invertebrate pathology is the variability in terminology and definition, which has led to confusion in scientific communication. The aim of this paper is to provide an overview of the pathological basis of bivalve disease (defensive, regressive and progressive phenomena) and contribute to the standardised terminology for bivalve molluscan disease in the context of comparative pathology. PMID:26215472

  20. Bivalves build their shells from amorphous calcium carbonate

    Science.gov (United States)

    Jacob, D. E.; Wirth, R.; Soldati, A. L.; Wehrmeister, U.

    2012-04-01

    One of the most common shell structures in the bivalve class is the prism and nacre structure. It is widely distributed amongst both freshwater and marine species and gives cultured pearls their sought-after lustre. In freshwater bivalves, both shell structures (prism and nacre) consist of aragonite. Formation of the shell form an amorphous precursor phase is a wide-spread strategy in biomineralization and presents a number of advantages for the organisms in the handling of the CaCO3 material. While there is already evidence that larval shells of some mollusk species use amorphous calcium carbonate (ACC) as a transient precursor phase for aragonite, the use of this strategy by adult animals was only speculated upon. We present results from in-situ geochemistry, Raman spectroscopy and focused-ion beam assisted TEM on three species from two different bivalve families that show that remnants of ACC can be found in shells from adult species. We show that the amorphous phase is not randomly distributed, but is systematically found in a narrow zone at the interface between periostracum and prism layer. This zone is the area where spherulitic CaCO3- structures protrude from the inner periostracum to form the initial prisms. These observations are in accordance with our earlier results on equivalent structures in freshwater cultured pearls (Jacob et al., 2008) and show that the original building material for the prisms is amorphous calcium carbonate, secreted in vesicles at the inner periostracum layer. Quantitative temperature calibrations for paleoclimate applications using bivalve shells are based on the Mg-Ca exchange between inorganic aragonite (or calcite) and water. These calibrations, thus, do not take into account the biomineral crystallization path via an amorphous calcium carbonate precursor and are therefore likely to introduce a bias (a so-called vital effect) which currently is not accounted for. Jacob et al. (2008) Geochim. Cosmochim. Acta 72, 5401-5415

  1. Light indirectly mediates bivalve habitat modification and impacts on seagrass

    DEFF Research Database (Denmark)

    Castorani, Max Christopher Nicholas; Glud, Ronnie N.; Hasler-Sheetal, Harald;

    2015-01-01

    by directly or indirectly influencing the effects of habitat-modifying organisms that are capable of simultaneously ameliorating and exacerbating multiple stressors. Itwas hypothesized that light availability changes seagrassmetabolismand thereby indirectly regulates bivalve habitat modification...... and respiration),mussels and lowlight availability exacerbated sulfide intrusion of eelgrass tissues. Surprisingly, sulfide stress did not affect plant growth, survival, or energy stores. Thus, habitat modification by musselsmay represent a risk to eelgrass, especially during low productivity conditions...

  2. Magnetosome-containing bacteria living as symbionts of bivalves

    OpenAIRE

    Dufour, Suzanne C.; Laurich, Jason R; Batstone, Rebecca T; McCuaig, Bonita; Elliott, Alexander, 1983-; Poduska, Kristin M

    2014-01-01

    Bacteria containing magnetosomes (protein-bound nanoparticles of magnetite or greigite) are common to many sedimentary habitats, but have never been found before to live within another organism. Here, we show that octahedral inclusions in the extracellular symbionts of the marine bivalve Thyasira cf. gouldi contain iron, can exhibit magnetic contrast and are most likely magnetosomes. Based on 16S rRNA sequence analysis, T. cf. gouldi symbionts group with symbiotic and free-living sulfur-oxidi...

  3. Liquid chromatography quadrupole linear ion trap mass spectrometry for multiclass screening and identification of lipophilic marine biotoxins in bivalve mollusks.

    Science.gov (United States)

    Wu, Haiyan; Guo, Mengmeng; Tan, Zhijun; Cheng, Haiyan; Li, Zhaoxin; Zhai, Yuxiu

    2014-09-01

    A liquid chromatography quadrupole linear ion trap mass spectrometry method with fast polarity switching and a scheduled multiple reaction monitoring algorithm mode was developed for multiclass screening and identification of lipophilic marine biotoxins in bivalve molluscs. A major advantage of the method is that it can detect members of all six groups of lipophilic marine biotoxins [okadaic acid (OA), yessotoxins (YTX), azaspiracids (AZA), pectenotoxins (PTX), cyclic imines (CI), and brevetoxins (PbTx)], thereby allowing quantification and high confidence identification from a single liquid chromatography tandem mass spectrometry (LC-MS/MS) injection. An enhanced product ion (EPI) library was constructed after triggered collection of data via information-dependent acquisition (IDA) of EPI spectra from standard samples. A separation method for identifying 17 target toxins in a single analysis within 12min was developed and tested. Different solid phase extraction sorbents, the matrix effect (for oyster, scallop, and mussel samples), and stability of the standards also were evaluated. Matrix-matched calibration was used for quantification of the toxins. The limits of detection were 0.12-13.6μg/kg, and the limits of quantification were 0.39-45.4μg/kg. The method was used to analyze 120 shellfish samples collected from farming areas along the coast of China, and 7% of the samples were found to be contaminated with toxins. The library search identified PbTx-3, YTX, OA, PTX2, AZA1, AZA2, and desmethylspirolide C (SPX1). Overall, the method exhibited excellent sensitivity and reproducibility, and it will have broad applications in the monitoring of lipophilic marine biotoxins. PMID:25086754

  4. Predation and habitat modification synergistically interact to control bivalve recruitment on intertidal mudflats

    OpenAIRE

    Van der Heide, Tjisse; Tielens, Elske; van der Zee, Els; Weerman, Ellen J.; Holthuijsen, Sander; Eriksson, Britas Klemens; Piersma, Theun; van de Koppel, Johan; Olff, Han

    2014-01-01

    Bivalves are key components of coastal ecosystems because they link pelagic and benthic food webs, and shape the landscape through habitat modification. Nevertheless, many bivalve stocks have dramatically declined, and recruitment failure due to (anthropogenically-) increased predation by mesopredators and loss of facilitation mechanisms have been separately hypothesized as underlying causes. Here, we tested the interactive effects of predation and habitat modification on bivalve recruitment ...

  5. Spatial synchronies in the seasonal occurrence of larvae of oysters (Crassostrea gigas) and mussels (Mytilus edulis/galloprovincialis) in European coastal waters

    Science.gov (United States)

    Philippart, Catharina J. M.; Amaral, Ana; Asmus, Ragnhild; van Bleijswijk, Judith; Bremner, Julie; Buchholz, Fred; Cabanellas-Reboredo, Miguel; Catarino, Diana; Cattrijsse, André; Charles, François; Comtet, Thierry; Cunha, Alexandra; Deudero, Salud; Duchêne, Jean-Claude; Fraschetti, Simonetta; Gentil, Franck; Gittenberger, Arjan; Guizien, Katell; Gonçalves, João M.; Guarnieri, Giuseppe; Hendriks, Iris; Hussel, Birgit; Vieira, Raquel Pinheiro; Reijnen, Bastian T.; Sampaio, Iris; Serrao, Ester; Pinto, Isabel Sousa; Thiebaut, Eric; Viard, Frédérique; Zuur, Alain F.

    2012-08-01

    Reproductive cycles of marine invertebrates with complex life histories are considered to be synchronized by water temperature and feeding conditions, which vary with season and latitude. This study analyses seasonal variation in the occurrence of oyster (Crassostrea gigas) and mussel (Mytilus edulis/galloprovincialis) larvae across European coastal waters at a synoptic scale (1000s of km) using standardised methods for sampling and molecular analyses. We tested a series of hypotheses to explain the observed seasonal patterns of occurrence of bivalve larvae at 12 European stations (located between 37°N and 60°N and 27°W and 18°E). These hypotheses included a model that stated that there was no synchronisation in seasonality of larval presence at all between the locations (null hypothesis), a model that assumed that there was one common seasonality pattern for all stations within Europe, and various models that supposed that the variation in seasonality could be grouped according to specific spatial scales (i.e., latitude, large marine ecosystems and ecoregions), taxonomic groups, or several combinations of these factors. For oysters, the best models explaining the presence/absence of larvae in European coastal waters were (1) the model that assumed one common seasonal pattern, and (2) the one that, in addition to this common pattern, assumed an enhanced probability of occurrence from south to north. The third best model for oysters, with less empirical support than the first two, stated that oysters reproduced later in the south than in the north. For mussels, the best models explaining the seasonality in occurrence of larvae were (1) the model that assumed four underlying trends related to large marine ecosystems, and (2) the one that assumed one common seasonal pattern for larvae occurrence throughout Europe. Such synchronies in larval occurrences suggest that environmental conditions relevant to bivalve larval survival are more or less similar at large

  6. Relating Productivity Events to Holocene Bivalve Shell Growth Rates

    Science.gov (United States)

    Huntley, J. W.; Krause, R. A.; Kowalewski, M.; Romanek, C. S.; Kaufman, D. S.; Simoes, M. G.

    2007-12-01

    The growth rate of a bivalve can be influenced by many environmental factors that can change during the life of the organism. In this contribution we present initial data from a millennium scale chronology to assess the relationship between ontogenetic growth in the bivalve Semele casali and paleoenvironmental conditions preserved in the shell using growth increment analysis, radiocarbon-calibrated amino acid racemization dating techniques, stable isotopes (C and O) and high spatial resolution (125-150 samples per cm of shell profile) trace element (Ba, Mn) analysis (LA-ICPMS). Time-averaged specimens of S. casali were dredged from two sites at 10 meters and 30 meters depth along the inner continental shelf at Ubatuba Bay in the Southeast Brazilian Bight, an area influenced by productivity pulses triggered by coastal runoff events and coastal upwelling. Seventy-five individual valves were dated using amino acid racemization (aspartic acid). Dates were calculated using an expanded version of a previously published relationship (Barbour Wood et al., 2006 Quaternary Research 323- 331) between aspartic acid ratios and AMS radiocarbon dates of twelve S. casali individuals from the same sampling locations. The resulting time series has complete coverage for the past three thousand years at centennial resolution. From this time series, a sub-sample of dated valves was selected for more detailed growth increment, stable isotope and high-resolution trace element (Ba/Ca and Mn/Ca) analyses. Oceanic productivity is expressed differentially in the trace element profiles of S. casali with elevated Ba/Ca and Mn/Ca ratios capturing nutrient input through coastal runoff events while elevated Ba/Ca and depressed Mn/Ca ratios represent input through coastal upwelling. Fluctuations in Ba/Ca and Mn/Ca are not correlated to fluctuations in relative growth throughout the ontogeny of an individual bivalve, nor are they expected to be as periods of increased productivity are transient

  7. A population dynamic model assessing options for managing eastern oysters (Crassostrea virginica) and triploid Suminoe oysters (Crassostrea ariakensis) in Chesapeake Bay

    OpenAIRE

    Dew, Jodi Rebecca

    2002-01-01

    A demographic population simulation model was developed to examine alternative fishery management strategies and their likely effects on the probability of extirpation of local eastern oyster (Crassostrea virginica) populations in the Chesapeake Bay. Management strategies include varying the minimum shell length-at-harvest, harvest rate, and rate and frequency of stocking of oyster seed with respect to varying salinities and oyster population densities. We also examined the rate of disease-me...

  8. Marine molluscs in environmental monitoring. II. Experimental exposure to selected pollutants

    Science.gov (United States)

    Bresler, Vladimir; Mokady, Ofer; Fishelson, Lev; Feldstein, Tamar; Abelson, Avigdor

    2003-10-01

    In an effort to establish biomonitoring programmes for routine and emergency monitoring of littoral marine habitats, organismal responses are examined in two ways: firstly, in controlled, laboratory studies, where the response may be accurately characterized; secondly, in field-collected specimens, with the hope of obtaining evidence regarding disturbances such as the ones caused by anthropogenic pollution. In many cases, there is a gap between the two types of studies, and different species and experimental and/or analytical procedures are used. In a series of recent studies, we have examined responses of field-collected molluscs, and interpreted our findings with respect to pollution. Here, we report a complementary study, in which molluscs collected from reference and polluted sites were exposed to cadmium or DDT under controlled laboratory conditions. Using fluorescent probes and microfluorometry, we examined the effect of these pollutants on paracellular permeability, lysosomal stability and metabolic status of mitochondria. Our findings indicate that molluscs from polluted sites are less affected, showing significantly smaller alterations in all examined parameters. These findings are in line with previous results showing higher levels of activity of cellular defence mechanisms in molluscs collected from polluted sites. Taken together, the results may be used to establish a reliable biomonitoring system. The sensitivity of the suggested methodology is also expected to qualify such a system for early warning.

  9. Predicting the Response of Molluscs to the Impact of Ocean Acidification

    Directory of Open Access Journals (Sweden)

    John M. Wright

    2013-04-01

    Full Text Available Elevations in atmospheric carbon dioxide (CO2 are anticipated to acidify oceans because of fundamental changes in ocean chemistry created by CO2 absorption from the atmosphere. Over the next century, these elevated concentrations of atmospheric CO2 are expected to result in a reduction of the surface ocean waters from 8.1 to 7.7 units as well as a reduction in carbonate ion (CO32− concentration. The potential impact that this change in ocean chemistry will have on marine and estuarine organisms and ecosystems is a growing concern for scientists worldwide. While species-specific responses to ocean acidification are widespread across a number of marine taxa, molluscs are one animal phylum with many species which are particularly vulnerable across a number of life-history stages. Molluscs make up the second largest animal phylum on earth with 30,000 species and are a major producer of CaCO3. Molluscs also provide essential ecosystem services including habitat structure and food for benthic organisms (i.e., mussel and oyster beds, purification of water through filtration and are economically valuable. Even sub lethal impacts on molluscs due to climate changed oceans will have serious consequences for global protein sources and marine ecosystems.

  10. Induction of gynogenetic haploidy in oyster Crassostrea gigas, using ultra violet irradiated sperms

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, U.

    Eggs of Crassostrea gigas were fertilized with sperms exposed to different doses of UV irradiations by keeping a constant rate of 121.47 ergs. mm/2 sec/1 and changing the period of exposure from 4 to 90 sec. Samples of larvae were analysed...

  11. Impact of an icy winter on the Pacific oyster (Crassostrea gigas Thunberg, 1793) populations in Scandinavia

    DEFF Research Database (Denmark)

    Strand, Åsa; Blanda, Elisa; Bodvin, Torjan;

    2012-01-01

    The Pacific oyster (Crassostrea gigas) is an invasive species that has dispersed into Scandinavia during the last few decades. The objective of this study was to evaluate the effects of extreme winter conditions on the mortality of the Pacific oyster in Scandinavia. The study was done by compiling...

  12. Salinity influences the biochemical response of Crassostrea angulata to Arsenic.

    Science.gov (United States)

    Moreira, Anthony; Figueira, Etelvina; Soares, Amadeu M V M; Freitas, Rosa

    2016-07-01

    The increasing rate of occurrence and persistence of climatic events causing salinity shifts, in combination with contamination, may further challenge organisms response to environmental stress. Hence, we studied the effects of different salinity levels (10, 20, 30 and 40) on the response of the oyster Crassostrea angulata to Arsenic (As) exposure (4 mg L(-1)). Total As, Na(+) and K(+) concentrations in oyster tissues were determined. Biochemical analysis were performed to assess osmotic regulation (CA), metabolism (ETS), enzymatic (SOD, CAT and GSTs) and non-enzymatic (GSH/GSSG and LPO) markers of oxidative stress. Results obtained showed significantly higher metabolic activities in oysters maintained in low salinity (10) exposure, coupled with higher As accumulation, as well as higher SOD and CAT activities, compared to higher salinities (30 and 40). GSTs activity and LPO levels were higher in oysters exposed to As at salinities 20, 30 and 40, compared to the same conditions without As. From our findings we concluded that the response of C. angulata to As is influenced by salinity. At the lowest salinity (10) oysters accumulated higher As concentrations, here attributed to higher metabolic rate involved in physiological osmoregulation, also stimulating antioxidant related enzymes activity (SOD and CAT) and thus preventing increased LPO (higher ETS activity also observed without As). On the contrary, at salinities 30 and 40 with As, antioxidant SOD and CAT were inhibited, enabling for LPO generation. Given our results, the effects of As on the oysters antioxidant capacity appears to be more deleterious under higher salinities (20, 30 and 40), comparing to salinity 10. The differentiated responses demonstrated in the present study in C. angulata oysters exposed to As under different salinities, bring new insights on the mechanisms of environmental adaptability of this species, namely to salinity shifts, and the interactions between such alterations and As

  13. Biochemical profile of oyster Crassostrea madrasensis and its nutritional attributes

    Directory of Open Access Journals (Sweden)

    K.K. Asha

    2014-01-01

    Full Text Available Oysters are highly esteemed sea food and considered a delicacy throughout the world. Yet this resource is not optimally utilised in several parts of the world. The aim of this study is to highlight its nutritional importance. Biochemical composition and nutritional attributes of oyster meat are discussed. Proximate composition, fatty acid and amino acid profiles and mineral content were determined in oysters (Crassostrea madrasensis. Moisture, protein, fat, carbohydrate and ash contents in the oyster were 82.64%, 9.41%, 3.25% 3.2% and 1.01%, respectively and it was rich in macro-minerals and trace elements especially selenium. Polyunsaturated fatty acids (PUFA were highest of the total lipids among which eicosapentaenoic acid, docosahexaenoic acid and linoleic acid were the prominent fatty acids. The n-3/n-6 index was high indicating a predominance of n-3 fatty acids in the species. Total amino acid content was 99.33 g/100 g crude protein, of which, essential amino acid lysine was the most abundant. Valine had the lowest essential amino acid score (EAAS (0.17 while threonine had the highest EAAS of 3.62. Chemical score was 17% and the lowest limiting amino acid was valine. Protein efficiency ratio, essential amino acid index and biological value of oyster were 3.92, 120.2 and 174.0, respectively which indicates that the protein is of superior quality. Data on biochemical composition, nutritional attributes and quality indices of C. madrasensis protein may prove important for future policies regarding exploitation of this species and for inducing favourable changes in consumer preferences.

  14. 双壳类线粒体基因组结构分析%Analysis of Mitochondrial Genomic Structures in Bivalves

    Institute of Scientific and Technical Information of China (English)

    孟学平; 申欣; 赵娜娜; 田美; 郑立波; 程汉良; 阎斌伦; 董志国

    2013-01-01

    chain ,and mitochondrial genes from Unionoida in the 2 chains. A few species (12 species from Unionoida ,2 species from Veneroida ,1 species from Mytiloida ,and 1 species from Myoida , species from oyster Crassostrea) mitochondrial genomes contain 13 protein-coding genes (PCGs) ,and the remainings are comprised of 12 PCGs ,w hich are lack of AT P8 gene. The gene arrangements of PCGs and rRNAs are identical within same genus or family ,including 4 species from Meretrix ,4 species from Crassostrea ,11 species from Unionidae and Margaritiferidae , two species (Mytilus edulis and M. galloprovincialis) from mussel Mytilus. The gene arrangements of 10 mitochondrial genomes from Ostreidae can be divided into 7 types. There were no shared gene blocks in mitochondrial genomes from Pectinidae except similar gene structures were detected in bay scallop Argopecten irradians irradians f arreri(NC_012977)and A. irradians(NC_009687). The mussels Mytilus edulis and M. trossulus from Mytilidae have very similar genomic structures ,and the genomic structure of Musculista senhousia is very special with a duplicated cox2 genes. The gene arrangement of Hiatella arctica from Myoida is very different from other species. The proportions of non-coding regions in mitogenomes are ranged from 7.6%to 40.3% ,the major non-coding region ranging from 374nt to 4341nt in size in bivalves. The minimum divergence is found to be 0.2-1.0/0-1.0 in Meretrix ,0.4-2.0/0-3.2 in Mytilus and 1.9-13.9/0-6.4 in oyster Crassostrea based on nucleotides of PCGs genes/amino acids of proteins.

  15. Selective breeding to improve resistance against summer mortality in the Pacific oyster Crassostrea gigas : results after 3 generations

    OpenAIRE

    Boudry, Pierre; Degremont, Lionel; Bedier, Edouard; Samain, Jean-francois

    2004-01-01

    Summer mortality of adults and juveniles has been reported in the Pacific oyster, Crassostrea gigas, for many years and in several countries. The French multidisciplinary program "Morest" aims to investigate the causes of the summer mortality in Crassostrea gigas. Within this program, we designed multi-site field experiments to assess to what extent genetic variability exists for summer mortality in French populations of C. gigas and to determine whether selective breeding could improve survi...

  16. Filtration in some tropical intertidal bivalves exposed to mercury and cadmium mixtures

    OpenAIRE

    Mohan, C.V.; N. R. Menon; Gupta, T.R.C.

    1986-01-01

    Three species of intertidal filter feeding bivalves (Modiolus carvalhoi, Modiolus sp. and Donax spiculum) exposed to mercury and cadmium filtered significantly less volume of water under individual metal and metal mixture stress. Mercury and cadmium in mixtures interacted additively and more than additively (Synergism) in depressing the filtration rate of the bivalves.

  17. Lower Oligocene bivalves of Ramanian Stage from Kachchh, Gujarat, India

    Science.gov (United States)

    Kachhara, R. P.; Jodhawat, R. L.; Devi, K. Bigyapati

    2012-04-01

    Marine Oligocene sequences in India outcrop only in western part of Kachchh. Earlier researchers have recognized the Oligocene strata under the Nari Series (Nagappa 1959; Chatterji and Mathur 1966). The Nari Series has a type area in Pakistan. It has two subdivisions - the Lower Nari (Lower Oligocene) and the Upper Nari (Upper Oligocene). It seems that there is no valid proof about the age of the Lower Nari due to lack of proper fauna (Eames 1975), and according to Pascoe (1962), the Upper Nari slightly transgress into Aquitanian (Lower Miocene), therefore, one has to be very cautious. Biswas and Raju (1971) reclassified the Oligocene strata of Kachchh and lithostratigraphically clubbed them as the Maniyara Fort Formation with type section along the Bermoti stream. This Formation has four members. The lower three members correspond to the Ramanian Stage (Lower Oligocene, Biswas 1971, 1973) while the uppermost to the Waiorian Stage (Upper Oligocene, Biswas 1965, 1971, 1973). The Ramanian Stage is characterized by large forams especially Nummulites fichteli, Nummulites fichteli intermedius, Lepidocyclina ( Eulepidina) dialata and Operculina sp. Several ostracods are also known to occur. Megafauna include bivalves, gastropods, echinoids, corals, mammals and reptiles. Concerning bivalves earlier researchers have recorded a few taxa namely Trisidos semitorta (Lamarck), Cubitostrea angulata (J de C Sowerby), Pecten ( Amussiopecten) labadyei d'Archiac and Haime, Periglypta puerpera (Linne') var. aglaurae Brongniart, Ostrea fraasi Mayer Eymer and listed Pecten laevicostatus J de C Sowerby, Callista pseudoumbonella Vredenburg and Clementia papyracea (Gray) from Kachchh as against overall 42 forms from the Nari Series as a whole (Vredenburg 1928). This tempted us to make an attempt to collect bivalve fauna systematically which are occurring prolifically in the Ramanian Stage. In the present work, for this purpose, sections are worked out around Lakhpat (23°50'N; 68°47'E

  18. Lower Oligocene bivalves of Ramanian Stage from Kachchh, Gujarat, India

    Indian Academy of Sciences (India)

    R P Kachhara; R L Jodhawat; K Bigyapati Devi

    2012-04-01

    Marine Oligocene sequences in India outcrop only in western part of Kachchh. Earlier researchers have recognized the Oligocene strata under the Nari Series (Nagappa 1959; Chatterji and Mathur 1966). The Nari Series has a type area in Pakistan. It has two subdivisions – the Lower Nari (Lower Oligocene) and the Upper Nari (Upper Oligocene). It seems that there is no valid proof about the age of the Lower Nari due to lack of proper fauna (Eames 1975), and according to Pascoe (1962), the Upper Nari slightly transgress into Aquitanian (Lower Miocene), therefore, one has to be very cautious. Biswas and Raju (1971) reclassified the Oligocene strata of Kachchh and lithostratigraphically clubbed them as the Maniyara Fort Formation with type section along the Bermoti stream. This Formation has four members. The lower three members correspond to the Ramanian Stage (Lower Oligocene, Biswas 1971, 1973) while the uppermost to the Waiorian Stage (Upper Oligocene, Biswas 1965, 1971, 1973). The Ramanian Stage is characterized by large forams especially Nummulites fichteli, Nummulites fichteli intermedius, Lepidocyclina (Eulepidina) dialata and Operculina sp. Several ostracods are also known to occur. Megafauna include bivalves, gastropods, echinoids, corals, mammals and reptiles. Concerning bivalves earlier researchers have recorded a few taxa namely Trisidos semitorta (Lamarck), Cubitostrea angulata (J de C Sowerby), Pecten (Amussiopecten) labadyei d’Archiac and Haime, Periglypta puerpera (Linne’) var. aglaurae Brongniart, Ostrea fraasi Mayer Eymer and listed Pecten laevicostatus J de C Sowerby, Callista pseudoumbonella Vredenburg and Clementia papyracea (Gray) from Kachchh as against overall 42 forms from the Nari Series as a whole (Vredenburg 1928). This tempted us to make an attempt to collect bivalve fauna systematically which are occurring prolifically in the Ramanian Stage. In the present work, for this purpose, sections are worked out around Lakhpat (23° 50′N; 68

  19. Mollusc communities in Bulgarian fens: predictive power of the environment, vegetation, and spatial structure in an isolated habitat

    Czech Academy of Sciences Publication Activity Database

    Horsák, M.; Hájek, Michal; Hájková, Petra; Cameron, R.; Cernohorsky, N.; Apostolova, I.

    2011-01-01

    Roč. 98, č. 8 (2011), s. 671-681. ISSN 0028-1042 Institutional research plan: CEZ:AV0Z60050516 Keywords : molluscs * spring fens * Bulgaria Subject RIV: EF - Botanics Impact factor: 2.278, year: 2011

  20. A preliminary catalogue of natural substances of opistobranch molluscs from Western Mediterranean and near Atlantic

    OpenAIRE

    Ávila Escartín, Conxita

    1992-01-01

    A list of opisthobranch molluscs species from the western Mediterranean and nearby Atlantic is presented. These species have natural products that are of interest because of their chemical structure, origin and/or function in benthic ecosystems. This review contains data on the origin and activity of these molecules, collection sites of the animals, and their bibliographic references. A discussion of these subjects is also included.

  1. Circadian Rhythms of Crawling and Swimming in the Nudibranch Mollusc Melibe leonina

    OpenAIRE

    Newcomb, James M; Kirouac, Lauren E.; NAIMIE, AMANDA A.; BIXBY, KIMBERLY A.; Lee, Colin; MALANGA, STEPHANIE; RAUBACH, MAUREEN; Watson, Winsor H.

    2014-01-01

    Daily rhythms of activity driven by circadian clocks are expressed by many organisms, including molluscs. We initiated this study, with the nudibranch Melibe leonina, with four goals in mind: (1) determine which behaviors are expressed with a daily rhythm; (2) investigate which of these rhythmic behaviors are controlled by a circadian clock; (3) determine if a circadian clock is associated with the eyes or optic ganglia of Melibe, as it is in several other gastropods; and (4) test the hypothe...

  2. On the diversity of mollusc intermediate hosts of Angiostrongylus costaricensis Morera & Cespedes, 1971 in southern Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Graeff Teixeira

    1993-09-01

    Full Text Available Veronicellid slugs are considered the most important intermediate hosts of Angiostrongylus costaricensis, an intra-arterial nematode of rodents. Studies undertaken in three localities in southern Brazil led to identification of molluscs other than veronicellid slugs as hosts of A. costaricensis: Limax maximus, Limax flavus and Bradybaena similaris. These data indicate a low host specificity of larval stages of A. costaricensis, as it has been reported to other congeneric species.

  3. One-trial associative learning modifies food odor preferences of a terrestrial mollusc

    OpenAIRE

    Sahley, Christie; Gelperin, Alan; Rudy, Jerry W.

    1981-01-01

    We present evidence of rapid and reliable associative learning by the terrestrial mollusc, Limax maximus. Slugs were exposed once to a pairing of a highly attractive food odor (potato or carrot) and a saturated solution of quinidine sulfate, a bitter-tasting plant substance. In comparison with control slugs, the exposed slugs subsequently displayed a markedly reduced preference for the odor paired with quinidine. This reduced odor preference was limited to the specific odor paired with quinid...

  4. "First class oysters" : progress and constgraints in genetic improvement of the Pacific oyster (Crassostrea gigas)

    OpenAIRE

    Boudry, Pierre

    2007-01-01

    The most significant genetic improvement for the production of Pacific oyster (Crassostrea gigas) up until now has been obtained through the production of triploids, particularly since the development of tetraploids in the mid 90s. Alternatively, quantitative genetics studies suggest that significant gains could be obtained in traits of aquacultural interest. However, the limited extent of hatchery propagation (compared with natural recruitment) in some countries and/or technical difficulties...

  5. Deregulation of the humoral immune response of the oyster (Crassostrea corteziensis) exposed to naphthalene

    OpenAIRE

    KJG Díaz-Resendiz; CA Romero-Bañuelos; ML Robledo-Marenco; AE Rojas-García; BS Barrón-Vibanco; IM Medina-Díaz; MI Girón-Pérez

    2014-01-01

    Naphthalene is one of the most abundant polycyclic aromatic hydrocarbons (PAH) in aquatic ecosystems, and it can cause alterations in the immune system of organisms that live there. The oyster Crassostrea corteziensis is a species native to the Eastern Tropical Pacific, with economic and ecological importance. In this study, we evaluated the effect of subacute exposure to sublethal concentrations of naphthalene on the parameters of the humoral immune response (lysozyme and phenoloxidase activ...

  6. Growth and Survival of the American Oyster Crassostrea virginica in Jamaica Bay, New York

    OpenAIRE

    Sarinsky, Gary; Carroll, Margaret A; Nduka, Ebere; Catapane, Edward J.

    2005-01-01

    Jamaica Bay is a major inlet opening to the Atlantic Ocean. It was abundant with oysters until early 1900's. Over-harvesting, pressure from predators, parasitic invasion and declining water quality often are cited as causes. Despite actions to arrest and reverse the pollution, oysters are not reestablished. We are studying factors relating to the rehabitation of Crassostrea virginica in Jamaica Bay to determine if the water quality and environmental conditions are suitable for their survival....

  7. Genetic variation and trade-offs for reproduction ans survival in the Pacific oyster Crassostrea gigas

    OpenAIRE

    Boudry, Pierre; Degremont, Lionel; Bedier, Edouard; Pouvreau, Stephane; Normand, Julien; Ernande, Bruno

    2006-01-01

    To date, the most significant method to genetically reduce reproductive effort in the Pacific oyster (Crassostrea gigas) has been through the production of triploids, especially since the development of tetraploid lines allowing the breeding of 'natural' triploids. Gametogenesis of triploid oysters is strongly reduced compared with diploids, although they are not fully sterile and can produce viable gametes and some progenies when crossed with diploids. Reduced reproductive allocation and hig...

  8. Den invasive art, Stillehavsøsters (Crassostrea gigas)ved Agger Tange, Limfjorden

    OpenAIRE

    Davids, Jens; Holm, Mark; Schollert, Michelle; Herring Rasmussen, Nicolai; Raith Richter, Stine

    2007-01-01

    Climate changes and the movement of the climate zones can have great influence on the ecosystems. Introduced species are for instants a huge problem around the world due to the possible damage it can cause on already existing ecosystems. This could be a problem if the introduced specie is invasive and spread to takeover the niche of native species. Due to the resent years with increased water temperature it has been possible for the invasive species Crassostrea gigas to reproduce in the Li...

  9. Dimensional Relationships in Crassostrea madrasensis (Preston) and C. gryphoides (Schlotheim) in Mangrove Ecosystem

    Digital Repository Service at National Institute of Oceanography (India)

    Nagi, H.M.; Shenai-Tirodkar, P.S.; Jagtap, T.G.

    variations and productivity of oyster population. As case attempts have been made to study Crassostrea spp. from mangrove and in the vicinity regions of Mandovi estuary of Goa. The data described and discussed in the present paper would be applicable..., width, whole weight, flesh wet weight and dry weight. Shell length, height and width were measured to the nearest 0.02 mm using Vernier calipers. The dimensional terms (length, height and width) applied to oysters followed2. The total weight, shell...

  10. Study of the antioxydant capacity in link with reproduction in the Pacific oyster Crassostrea gigas

    OpenAIRE

    Béguel, Jean-Philippe

    2012-01-01

    The "cost of reproduction" is a concept defining that a high reproductive investment has a price that is paid later by an acceleration of senescence. That may translate tradeoff between reproduction and other physiological functions such as antioxidant defense. In the Pacific oyster Crassostrea gigas, reproduction is a major physiological function. In a study led to understand the summer mortalities affecting this species, a negative correlation between reproductive effort and survival was ob...

  11. Viral gametocytic hypertrophy of Crassostrea gigas in France: from occasional records to disease emergence?

    OpenAIRE

    Garcia, Celine; Robert, Maeva; ARZUL, Isabelle; Chollet, Bruno; Joly, Jean-pierre; Miossec, Laurence; Comtet, Thierry; Berthe, Franck

    2006-01-01

    Viral gametocytic hypertrophy was reported for the first time in 2001 in Pacific oyster Crassostrea gigas in France. Since this date, the number of reported cases and the distribution area have increased every year; however, the cases are not associated with macroscopic signs or increased mortality rates. Both male and female gametes were hypertrophied and basophilic inclusions were observed in gamete nuclei, Transmission electron microscopy revealed the presence of viral particles in these i...

  12. Selective extinction among Early Jurassic bivalves: A consequence of anoxia

    Science.gov (United States)

    Aberhan, Martin; Baumiller, Tomasz K.

    2003-12-01

    Analyses of taxonomically standardized data sets demonstrate several statistically robust extinction patterns in Early Jurassic bivalve species from northwest Europe and the Andean basins of South America. In both regions, extinction intensities were significantly enhanced in late Pliensbachian and early Toarcian time as compared to all other time intervals. The same intervals (except for the early Toarcian of South America) also represent times of unusual extinction selectivity, with infaunal taxa suffering distinctly more than epifaunal forms. As infaunal suspension feeders are extremely rare components of Early Jurassic oxygen-controlled macrofaunas, these results are entirely compatible with sedimentological and geochemical data suggesting that widespread anoxia was a principal cause of the diversity crisis. Although many biotic traits that enhance survivorship during background times seem to be irrelevant during major mass extinctions, patterns of survivorship selectivity may provide more distinct clues to the causes of less severe mass extinctions.

  13. Evolutionary implications of endosymbiont diversity within lucinid bivalves

    Science.gov (United States)

    Garcia, A. M.; Thiessen, M.; Aronowsky, A.; Anderson, L.; Bao, H.; Engel, A.

    2007-12-01

    Bacterial endosymbiosis is widespread among Bivalvia. Symbiosis between lucinid bivalves and sulfur-oxidizing (thiotrophic) bacteria has received recent attention, as lucinids are one of the geologically oldest extant bivalve clades to possess endosymbionts. However, the ecological and evolutionary relationships between host and symbiont are poorly understood, and reconstructing the evolutionary history and geological significance of lucinid endosymbiosis requires additional knowledge and characterization of endosymbiont ecology and taxonomic diversity. Our goal was to characterize the bacterial diversity of a modern lucinid habitat in order to evaluate possible lucinid endosymbiont diversity. Host organisms ( Lucinisca nassula and Phacoides pectinatus) and sediment cores were collected from geochemically reducing and sulfide-rich sea grass beds. PCR amplification and sequencing of bacterial 16S rRNA genes from the sediment cores retrieved 13 major taxonomic groups, including equally dominant Chloroflexi, Delta-, and Gammaproteobacteria, and rare Bacteroides, Acidobacteria, Spirochaetes, and Firmicutes. Less than 2% of the sequences were affiliated with uncultured gammaproteobacterial symbiont groups, but were not closely related to the sequences retrieved from the lucinid gills. Moreover, our analyses uncovered multiple gene sequence populations within an individual, as well as across individuals within the same sampling site. Additional habitat-host-symbiont diversity from three other lucinid taxa and from six geographically distinct habitat sites is also expanding the previously understood diversity of thiotrophic endosymbionts, and specifically that the lucinid symbionts are probably not a monophyletic species. These data suggest that thiotrophic bacteria are recruitable for endosymbiosis and are widely distributed in reducing marine environments. But, because of the diversity of bacteria in any one habitat, symbionts may be metabolically and physiologically

  14. Magnetosome-containing bacteria living as symbionts of bivalves.

    Science.gov (United States)

    Dufour, Suzanne C; Laurich, Jason R; Batstone, Rebecca T; McCuaig, Bonita; Elliott, Alexander; Poduska, Kristin M

    2014-12-01

    Bacteria containing magnetosomes (protein-bound nanoparticles of magnetite or greigite) are common to many sedimentary habitats, but have never been found before to live within another organism. Here, we show that octahedral inclusions in the extracellular symbionts of the marine bivalve Thyasira cf. gouldi contain iron, can exhibit magnetic contrast and are most likely magnetosomes. Based on 16S rRNA sequence analysis, T. cf. gouldi symbionts group with symbiotic and free-living sulfur-oxidizing, chemolithoautotrophic gammaproteobacteria, including the symbionts of other thyasirids. T. cf. gouldi symbionts occur both among the microvilli of gill epithelial cells and in sediments surrounding the bivalves, and are therefore facultative. We propose that free-living T. cf. gouldi symbionts use magnetotaxis as a means of locating the oxic-anoxic interface, an optimal microhabitat for chemolithoautotrophy. T. cf. gouldi could acquire their symbionts from near-burrow sediments (where oxic-anoxic interfaces likely develop due to the host's bioirrigating behavior) using their superextensile feet, which could transfer symbionts to gill surfaces upon retraction into the mantle cavity. Once associated with their host, however, symbionts need not maintain structures for magnetotaxis as the host makes oxygen and reduced sulfur available via bioirrigation and sulfur-mining behaviors. Indeed, we show that within the host, symbionts lose the integrity of their magnetosome chain (and possibly their flagellum). Symbionts are eventually endocytosed and digested in host epithelial cells, and magnetosomes accumulate in host cytoplasm. Both host and symbiont behaviors appear important to symbiosis establishment in thyasirids. PMID:24914799

  15. Life history traits to predict biogeographic species distributions in bivalves

    Science.gov (United States)

    Montalto, V.; Rinaldi, A.; Sarà, G.

    2015-10-01

    Organismal fecundity ( F) and its relationship with body size (BS) are key factors in predicting species distribution under current and future scenarios of global change. A functional trait-based dynamic energy budget (FT-DEB) is proposed as a mechanistic approach to predict the variation of F and BS as function of environmental correlates using two marine bivalves as model species ( Mytilus galloprovincialis and Brachidontes pharaonis). Validation proof of model skill (i.e., degree of correspondence between model predictions and field observations) and stationarity (i.e., ability of a model generated from data collected at one place/time to predict processes at another place/time) was provided to test model performance in predicting the bivalve distribution throughout the 22 sites in the Central Mediterranean Sea under local conditions of food density and body temperature. Model skill and stationarity were tested through the estimate of commission (i.e., proportion of species' absences predicted present) and omission (i.e., proportion of presences predicted absent) errors of predictions by comparing mechanistic predicted vs. observed F and BS values throughout the study area extrapolated by lab experiments and literature search. The resulting relationship was reliable for both species, and body size and fecundity were highly correlated in M. galloprovincialis compared to B. pharaonis; FT-DEB showed correct predictions of presence in more than 75 % of sites, and the regression between BS predicted vs. observed was highly significant in both species. Whilst recognising the importance of biotic interactions in shaping the distribution of species, our FT-DEB approach provided reliable quantitative estimates of where our species had sufficient F to support local populations or suggesting reproductive failure. Mechanistically, estimating F and BS as key traits of species life history can also be addressed within a broader, scale-dependent context that surpasses the

  16. Paleoenvironmental and sclerochronological reconstruction of Crassostrea gryphoides Miocene biostromes from Crete island (Greece)

    Science.gov (United States)

    Koskeridou, E.; Agiadi, K.

    2012-04-01

    The mangrove oyster Crassostrea gasar (Adanson, 1757) is a keystone species mainly along the African Atlantic coasts. It forms biostromes on muddy coasts and typically associated with river mouths in the intertidal zone in depths of 0.60 up to 1 m1. Similarly, many biostrome structures of the fossilized Crassostrea gryphoides are found within Cenozoic deposits of Greece2. Since Crassostrea gasar is the phyllogenetically corresponding species of Crassostrea gryphoides, it is investigated whether the fossil biostromes formed under environmental conditions similar to those favored by modern Crassostrea gasar and if growth rate and longevity are comparable. A biostrome from the Tortonian of Heraklion district, Crete island (southern Greece) was studied to investigate the paleoenvironmental conditions and the life history of these oysters. The shells are big, ranging up to 40 cm in length, thick and positioned mainly horizontally. The biostrome is approximately 2 m in thickness and a few meters in length. Individual oysters, associated fauna and lithologic samples were collected. Paleoenvironmental interpretation was based on the analysis of the oyster taphonomy, the associated fauna and the sclerochronology/stable isotopic geochemistry of the oyster shells. The biostrome is observed in sandy marl which laterally contains Veneridae, Melongena, Terebralia bidentata and oligospecific microfossils, mainly Ammonia beccarii and Miliolids. Borings by many ichnotaxa occur on the external and internal surface of the oyster shells during the pre and /or post-mortem. Using a micromill, successive samples were taken along the hinge/ligament region of an oyster for isotopic analyses. The δ18O values ranged from -2.9 to 0.1. The wide range of values supports the interpretation of changing environmental conditions. The δ13C values ranged from -2.6 to -0.1. A correlation between δ18O and δ13C was observed. The profiles exhibit cyclicity with respect to isotopic and Sr/Ca ratios

  17. Metals and organotins in multiple bivalve species in a one-off global survey

    DEFF Research Database (Denmark)

    Larsen, Martin Mørk; Strand, Jakob; Christensen, Jan H.;

    2011-01-01

    contamination levels on a global scale. Metal concentrations in nine bivalve species were normalised to the Mytilidae family using conversion factors based on cosampled species and literature bioconcentration factors. The lowest metal and tributyltin concentrations were below background assessment...

  18. Independent phylogenetic origins of methanotrophic and chemoautotrophic bacterial endosymbioses in marine bivalves

    OpenAIRE

    Distel, D L; Cavanaugh, Colleen Marie

    1994-01-01

    The discovery of bacterium-bivalve symbioses capable of utilizing methane as a carbon and energy source indicates that the endosymbionts of hydrothermal vent and cold seep bivalves are not restricted to sulfur-oxidizing chemoautotrophic bacteria but also include methanotrophic bacteria. The phylogenetic origin of methanotrophic endosymbionts and their relationship to known symbiotic and free-living bacteria, however, have remained unexplored. In situ localization and phylogenetic analysis of ...

  19. Influence of intertidal recreational fisheries and 'bouchot' mussel culture on bivalve recruitment.

    Science.gov (United States)

    Toupoint, Nicolas; Barbier, Pierrick; Tremblay, Réjean; Archambault, Philippe; McKindsey, Christopher W; Winkler, Gesche; Meziane, Tarik; Olivier, Frédéric

    2016-06-01

    In coastal environments, fishing and aquaculture may be important sources of disturbance to ecosystem functioning, the quantification of which must be assessed to make them more sustainable. In the Chausey Archipelago, France, recreational fishing and commercial shellfish farming are the only two evident anthropogenic activities, dominated by bivalve hand-raking and 'bouchot' mussel culture, respectively. This study evaluates the impact of both activities on bivalve recruitment dynamics by comparing primary recruitment intensity (short-term effect) and recruitment efficiency (medium-term effect) by sampling bivalves in reference (undisturbed) and disturbed (i.e. subjected to hand-raking or in 'bouchot' mussel culture areas) parcels throughout and at the end of the recruitment season, respectively. Specific hypotheses evaluated were that (H1) bivalve hand-raking negatively affects bivalve recruitment and that (H2) 'bouchot' mussel culture promotes bivalve recruitment. Patterns in bivalve community structure in reference parcels (i.e. natural pattern) differed between initial and final recruitment, underlining the great importance of early post-settlement processes, particularly secondary dispersal. Primary recruitment intensity was inhibited in hand-raking parcels whereas it was promoted in 'bouchot' mussel culture parcels, but the effect on recruitment efficiency was muted for both activities due to post-settlement processes. Nevertheless, the importance of effects that occur during the first step of recruitment should not be ignored as they may affect bivalve communities and induce immediate consequences on the trophic web through a cascade effect. Finally, it is highlighted that hand-raking damages all life stages of the common cockle Cerastoderma edule, one of the major target species, suggesting that this activity should be managed with greater caution than is currently done. PMID:27039134

  20. An overview of chemosynthetic symbioses in bivalves from the North Atlantic and Mediterranean Sea

    OpenAIRE

    Duperron, S.; Gaudron, S.M.; Rodrigues, C. F.; M. R. Cunha; C. Decker; Olu, K

    2012-01-01

    Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria which ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, East America, the Gulf o...

  1. An integrated ecosystem approach for assessing the potential role of cultivated bivalve shells as part of the carbon trading system

    DEFF Research Database (Denmark)

    Filgueira, Ramón; Byron, C.J.; Comeau, L.A.;

    2015-01-01

    The role of bivalve mariculture in the CO2 cycle has been commonly evaluated as the balance between respiration, shell calcium carbonate sequestration and CO2 release during biogenic calcification. However, this approach neglects the ecosystem implications of cultivating bivalves at high densities......, e.g. the impact on phytoplankton dynamics and benthic-pelagic coupling, which can significantly contribute to the CO2 cycle. Therefore, an ecosystem approach that accounts for the trophic interactions of bivalve aquaculture, including dissolved and particulate organic and inorganic carbon cycling......, is needed to provide a rigorous assessment of the role of bivalve mariculture in the CO2 cycle. On the other hand, the discussion about the inclusion of shells of cultured bivalves into the carbon trading system should be framed in the context of ecosystem goods and services. Humans culture bivalves...

  2. Calibration of the carbonate `clumped isotope' paleotemperature proxy using mollusc shells and benthic foraminiferal tests

    Science.gov (United States)

    Came, R. E.; Curry, W. B.; Weidman, C. R.; Eiler, J. M.

    2007-12-01

    It has recently been shown that the carbonate `clumped isotope' thermometer can provide temperature constraints that depend only on the isotopic composition of carbonate (in particular, on the proportion of 13C and 18O that form bonds with each other), and that do not require assumptions about the isotopic composition of the water in which the carbonate formed (Ghosh et al., 2006). Furthermore, this novel method permits the calculation of seawater δ18O based on the clumped isotope temperature estimates and the simultaneously obtained δ18O of carbonate, thereby enabling the extraction of global ice volume estimates for both the recent and distant geologic past. Here we present clumped isotope analyses of several naturally occurring marine carbonates that calcified at known temperatures in the modern ocean. First, we analyzed benthic foraminiferal tests from six high-quality multicore tops collected in the Florida Strait, spanning a temperature range of 9.3-20.2 degrees C. Second, we analyzed shallow-water mollusc shells from a variety of different climate regimes, spanning a temperature range of 2.5-26.0 degrees C. We find that the calcitic foraminiferal species Cibicidoides spp. agrees well with the inorganic calcite precipitation experiments of Ghosh et al. (2006), while the aragonitic species Hoeglundina elegans is significantly offset. Similarly, clumped isotope results obtained from aragonitic mollusc shells also reveal an offset from the Ghosh et al. (2006) trend, although the offset observed in mollusc aragonite is quite different in nature from that observed in foraminiferal aragonite. Assuming our estimates of the growth temperatures of these naturally occurring organisms are correct, these results suggest that there are vital effects associated with the stable isotope compositions of the aragonite-precipitating organisms examined in this study; further work will be required to determine their cause. Nevertheless, the internal coherence of trends for

  3. Tissue preservation biases in stable isotopes of fishes and molluscs from Patagonian lakes.

    Science.gov (United States)

    Correa, C

    2012-11-01

    Field work commonly involves preserving samples for later use; however, most preservation methods distort stable-isotope (SI) signatures that are of interest to ecologists. Although preservation of muscle samples with table salt and rubbing alcohol affected the SI (δ(13)C and δ(15)N) of important consumers in Patagonian lakes (molluscs and fishes), variation among individuals and lakes generally exceeded that among preservation treatments. Mathematical corrections for these preservation biases are provided, and a potentially bias-free preservation by air-drying is suggested. PMID:23130701

  4. Effects of cadmium on anaerobic energy metabolism and mRNA expression during air exposure and recovery of an intertidal mollusk Crassostrea virginica

    International Nuclear Information System (INIS)

    Marine organisms are exposed to periodical oxygen deficiency and pollution stress in estuarine and coastal zones which may strongly affect their performance and survival. We studied the combined effects of exposure to a common pollutant, cadmium (Cd), and intermittent anoxia on anaerobic metabolism, energy status and mRNA expression of 13 genes involved in and/or controlled by the hypoxia inducible factor-1 (HIF-1) pathway in hepatopancreas of an intertidal bivalve, the eastern oyster Crassostrea virginica. In control oysters, prolonged anoxia resulted in a selective suppression of nitric oxide synthase (NOS) and upregulation of cytochrome c oxidase subunit IV (COX4) while the levels of other transcripts remained unchanged. During post-anoxic recovery, mRNA expression of hypoxia inducible factor-1α (HIF-1α) was elevated, phosphoenolpyruvate carboxykinase (PEPCK), NOS and LON protease suppressed, and mRNA expression of other studied genes not changed. Notably, most of the key glycolytic genes that are stimulated by HIF-1 in mammals, either remained unchanged or were downregulated in anoxic oysters suggesting a different mechanism of molecular response to oxygen deficiency. Patterns of transcriptional response during anoxia and reoxygenation were significantly altered by Cd exposure in a gene-specific manner. Anaerobic metabolism (indicated by accumulation of L-alanine, succinate and acetate during anoxia) was also suppressed in Cd-exposed oysters. In control oysters, ATP turnover rate (MATP) during anoxia was mostly sustained by anaerobic glycolysis with negligible contributions from ATP and PLA breakdown. In contrast, in Cd-exposed oysters ATP breakdown contributed significantly to anaerobic MATP. Thus, while control oysters could efficiently defend the ATP levels and tissue energy status during prolonged anoxia, Cd-exposed oysters experienced a disturbance in tissue energy balance indicated by the depletion of ATP, a rapid decline in adenylate energy charge and

  5. Strontium and barium incorporation into freshwater bivalve shells

    Science.gov (United States)

    Zhao, Liqiang; Schöne, Bernd R.

    2015-04-01

    Despite strong vital control, trace elements of bivalve shells can potentially serve as proxies of environmental change. However, to reconstruct past environments with the geochemical properties of the shells and determine the degree to which the element levels are biologically influenced, it is essential to experimentally determine the relationship between environmental variables and the element composition of the shells. In particular, the trace element geochemistry of freshwater bivalve shells has so far received little attention. Here, we present a controlled laboratory experiment that aimed at providing a better understanding of the influence of changing environmental variables on the incorporation of trace elements into freshwater bivalve shells. Under controlled conditions, Asian clams Corbicula fluminea were reared for 5 weeks in three sets of experiments: (1) different water temperature (10, 16, and 22° C) and different food levels (an equally mixed Scenedesmu quadricanda and Chlorella vulgaris at rations of 0.4, 2, 4, and 8 × 104 cells ml-1 d-1); (2) different water temperature (10, 16, and 22° C) and different element levels (Sr, Ba); (3) five sediment types (sand, slightly muddy sand, muddy sand, slightly sandy mud and mud). In the first set of experiments, shell Sr/Ca showed a significantly negative correlation with temperature, where Sr/Ca decreased linearly by about 1.6 to 2.1% per 1° C, but responded far more weakly to food availability. On the other hand, temperature and food availability affected shell Ba/Ca ratios, which potentially confounds the interpretation of Ba/Ca variations. Moreover, shell Sr/Ca and Ba/Ca exhibited a clearly negative dependence on shells growth rate that varied significantly among combinations of temperature and food availability. In the second set of experiments, shell Sr/Ca and Ba/Ca were positively and linearly related to water Sr/Ca and Ba/Ca for all temperatures. However, significantly negative effects of

  6. A molecular palaeobiological hypothesis for the origin of aplacophoran molluscs and their derivation from chiton-like ancestors.

    Science.gov (United States)

    Vinther, Jakob; Sperling, Erik A; Briggs, Derek E G; Peterson, Kevin J

    2012-04-01

    Aplacophorans have long been argued to be basal molluscs. We present a molecular phylogeny, including the aplacophorans Neomeniomorpha (Solenogastres) and Chaetodermomorpha (Caudofoveata), which recovered instead the clade Aculifera (Aplacophora + Polyplacophora). Our relaxed Bayesian molecular clock estimates an Early Ordovician appearance of the aculiferan crown group consistent with the presence of chiton-like molluscs with seven or eight dorsal shell plates by the Late Cambrian (approx. 501-490 Ma). Molecular, embryological and palaeontological data indicate that aplacophorans, as well as chitons, evolved from a paraphyletic assemblage of chiton-like ancestors. The recovery of cephalopods as a sister group to aculiferans suggests that the plesiomorphic condition in molluscs might be a morphology similar to that found in monoplacophorans. PMID:21976685

  7. Anoxic survival potential of bivalves: (arte)facts.

    Science.gov (United States)

    de Zwaan, Albertus; Babarro, Jose M F; Monari, Marta; Cattani, Otello

    2002-03-01

    The anoxic survival time of the bivalves Chamelea gallina, Cerastoderma edule and Scapharca inaequivalvis from two different ecosystems and differing anoxia tolerances was studied in static (closed) and flow-through systems. The antibiotics chloramphenicol, penicillin and polymyxin were added, and molybdate (specific inhibitor of the process of sulfate reduction). Survival in (near) anoxic seawater of Chamelea was studied in a static system by comparing untreated seawater with autoclaved seawater and untreated clams with clams incubated in well-aerated seawater, containing the broad-spectrum antibiotic chloramphenicol, prior to the anoxic survival test. With untreated clams and natural seawater (median mortality time 2.4 days) a decrease in pH and exponential accumulation of sulfide and ammonium was observed in the anoxic medium, indicating excessive growth of (sulfate reducing) bacteria. In sterilized seawater LT50 (2.1 days) was not significantly different and again considerable amounts of ammonium and sulfide accumulated. However, pre-treatment of clams with chloramphenicol resulted in an increase of LT50 (11.0 days) by approximately fivefold. Accumulation of ammonium and sulfide was retarded, but was finally even stronger than in the medium containing untreated clams. Median mortality times were 2.5 and 2.4 days for Chamelea and 2.7 and 2.9 days for Cerastoderma for static and flow-through incubations, respectively. Addition of chloramphenicol increased strongly survival time in both systems with corresponding values of 11.0 and 16.3 days for Chamelea, and 6.4 and 6.5 days for Cerastoderma. LT50 of Scapharca in anoxic seawater was 14.4 days. Chloramphenicol and penicillin increased median survival time to 28.5 and 28.7 days, respectively, whereas polymyxin displayed no effect (LT50=13.6 days). Molybdate added to artificial sulfate free seawater blocked biotic sulfide formation, but did not improve survival time (LT50=13.7 days). Overall the results indicate

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

    OpenAIRE

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

    2014-01-01

    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: ...

  9. A checklist of malacofauna of the Vellar Estuarine Mangroves, India

    Directory of Open Access Journals (Sweden)

    K. Kesavan

    2009-07-01

    Full Text Available A survey conducted to know the diversity of malacofauna in Vellar estuarine mangroves (southeast coast of India. In this study, 13 species of molluscs (10 species of gastropods - Melampus ceylonicus, Cerithidea cingulata, Cassidula nucleus, Pythia plicata, Neritina (Dostia violacea, Littorina scabra, Littorina melanostoma, Ellobium aurisjudae, C. obtusa T. telescopium and Assiminea nitida and 3 species of bivalves - Perna viridis, Crassostrea madrasensis and Modiolus metcalfei were recorded. M. pulchella, C. obtusa, L. scabra and N. violacea were found arboreal. T. telescopium, C. cingulata and E. aurisjudae were found crawling on the intertidal mud.

  10. Trace Element Uptake in Marine Bivalve Shells Constraints from Field- and Laboratory Studies

    Science.gov (United States)

    Klünder, M.; Hippler, D.; Witbaard, R.; Frei, D.; Immenhauser, A.

    2006-12-01

    There is an increasing interest in the use of the trace element signatures recorded in calcium carbonate skeletons of marine organisms as archives of past and present environmental conditions, such as temperature, salinity or nutrition level. Because of their global occurrence in the modern and ancient oceans, the trace element chemistry of bivalve shells might be used as a potential proxy for present and past environmental conditions. If the composition of bivalve shells, for instance, can be shown to represent the environment in which they lived, then shells can be used to investigate conditions in the lifetime of the animal. And as the shell material is sequentially deposited, an understanding of the internal shell structure will enable time- resolution of the analyses. Therefore, the trace element signature of bivalve shells may provide an important record of climate changes and global geochemical cycles. One of the difficulties of using the trace element signatures of bivalve shells as proxies for environmental conditions is that little is known about the mechanisms by which the trace elements are incorporated into the shells. There has been quite an amount of research into the use of bivalve shell chemistry as proxy for one or more environmental parameters, but there are relatively few datasets in which both bivalve shells and the water in which the animals lived have been analysed. It is as yet not clear to what extent the trace element incorporation into bivalve shells is governed by biological processes, like growth rate and metabolism of the animals, or by physical and crystal chemical parameters. An added difficulty is that the existing data do suggest that trace element uptake in bivalve shells may be species specific. Therefore, studies that investigate the relationships between the content of these elements in the shells and the ambient water and the possible incorporation mechanisms are needed if the potential that bivalve shells offer as

  11. Ecotoxicological effects of metal pollution in two mollusc species from the Spanish South Atlantic littoral

    International Nuclear Information System (INIS)

    Metal accumulation and some of their biochemical effects have been studied in oysters (Crassostrea angulata) and mussels (Mytilus galloprovincialis) of the South Atlantic Spanish littoral. Especial attention has been paid to antioxidant defences and oxidative damage to biomolecules. Deep differences in the response of oysters and mussels to metal pollution were found. Oysters, with the higher metal loads of both species, showed increased antioxidant defences, and less extensive oxidative damage. In contrast, mussels, which accumulated much lower metal concentrations, showed clear increases in oxidized biomolecules, in agreement with their low increases in the antioxidant defence mechanisms. Our results suggest that mussels are more sensitive and less well adapted to metal pollution, probably explaining their absence in the most contaminated studied site, Mazagon. We conclude that oysters can be used as more sensitive bioindicator of pollution in the South Spanish littoral, and as a suitable model to study the adaptation to metal pollution. - Oysters adapt to metal pollution while mussels are more sensitive

  12. Changing restoration rules: exotic bivalves interact with residence time and depth to control phytoplankton productivity

    Science.gov (United States)

    Lucas, Lisa V.; Thompson, Janet K.

    2012-01-01

    Non-native species are a prevalent ecosystem stressor that can interact with other stressors to confound resource management and restoration. We examine how interactions between physical habitat attributes and a particular category of non-native species (invasive bivalves) influence primary production in aquatic ecosystems. Using mathematical models, we show how intuitive relationships between phytoplankton productivity and controllable physical factors (water depth, hydraulic transport time) that hold in the absence of bivalves can be complicated—and even reversed—by rapid bivalve grazing. In light-limited environments without bivalves, shallow, hydrodynamically “slow” habitats should generally have greater phytoplankton biomass and productivity than deeper, “faster” habitats. But shallower, slower environments can be less productive than deeper, faster ones if benthic grazing is strong. Moreover, shallower and slower waters exhibit a particularly broad range of possible productivity outcomes that can depend on whether bivalves are present. Since it is difficult to predict the response of non-native bivalves to habitat restoration, outcomes for new shallow, slow environments can be highly uncertain. Habitat depth and transport time should therefore not be used as indicators of phytoplankton biomass and production where bivalve colonization is possible. This study provides for ecosystem management a particular example of a broad lesson: abiotic ecosystem stressors should be managed with explicit consideration of interactions with other major (including biotic) stressors. We discuss the applicability and management implications of our models and results for a range of aquatic system types, with a case study focused on the Sacramento-San Joaquin Delta (California, USA). Simple mathematical models like those used here can illuminate interactions between ecosystem stressors and provide process-based guidance for resource managers as they develop strategies

  13. Intracellular Oceanospirillales bacteria inhabit gills of Acesta bivalves.

    Science.gov (United States)

    Jensen, Sigmund; Duperron, Sébastien; Birkeland, Nils-Kåre; Hovland, Martin

    2010-12-01

    A novel bacterium was discovered in the gills of the large bivalve Acesta excavata (Limidae) from coral reefs on the northeast Atlantic margin near the shelf break of the fishing ground Haltenbanken of Norway, and confirmed present in A. excavata from a rock-wall in the Trondheimsfjord. Purified gill DNA contained one dominant bacterial rRNA operon as indicated from analysis of broad range bacterial PCR amplicons in denaturant gradient gels, in clone libraries and by direct sequencing. The sequences originated from an unknown member of the order Oceanospirillales and its 16S rRNA gene fell within a clade of strictly marine invertebrate-associated Gammaproteobacteria. Visual inspection by fluorescent in situ hybridization and transmission electron microscopy indicated a pleomorphic bacterium with no visible cell wall, located in aggregates inside vacuoles scattered within the gill cells cytoplasm. Intracellular Oceanospirillales exist in bathymodiolin mussels (parasites), Osedax worms and whiteflies (symbionts). This bacterium apparently lives in a specific association with the Acesta. PMID:21044098

  14. Deregulation of the humoral immune response of the oyster (Crassostrea corteziensis exposed to naphthalene

    Directory of Open Access Journals (Sweden)

    KJG Díaz-Resendiz

    2014-01-01

    Full Text Available Naphthalene is one of the most abundant polycyclic aromatic hydrocarbons (PAH in aquatic ecosystems, and it can cause alterations in the immune system of organisms that live there. The oyster Crassostrea corteziensis is a species native to the Eastern Tropical Pacific, with economic and ecological importance. In this study, we evaluated the effect of subacute exposure to sublethal concentrations of naphthalene on the parameters of the humoral immune response (lysozyme and phenoloxidase activity, and nitric oxide production on the oyster C. corteziensis. The results indicated that naphthalene, under the conditions tested, significantly deregulated the parameters evaluated. This could increase susceptibility to infections and therefore affect oyster production.

  15. Massive settlements of the Pacific oyster, Crassostrea gigas, in Scandinavia : Invasion note

    DEFF Research Database (Denmark)

    Wrange, Anna-Lisa; Valero, Johanna; Harkestad, Lisbeth S.;

    2010-01-01

    the establishment of Pacific oysters in Scandinavia. However, recent surveys reveal that the Pacific oyster is now established in many areas in Scandinavia. The biomass of oysters in the Danish Wadden Sea has increased dramatically between 2005 and 2007, large numbers were observed along the Swedish......The Pacific oyster (Crassostrea gigas) is an important aquaculture species world-wide. Due to its wide environmental tolerance and high growth rate, it has also become a successful invader in many areas, leading to major ecosystem changes. Low water temperatures were previously believed to restrict...

  16. Massive settlements of the Pacific oyster, Crassostrea gigas, in Scandinavia : Original paper

    DEFF Research Database (Denmark)

    Wrange, Anna-Lisa; Valero, Johanna; Harkestad, Lisbeth S.;

    2010-01-01

    the establishment of Pacific oysters in Scandinavia. However, recent surveys reveal that the Pacific oyster is now established in many areas in Scandinavia. The biomass of oysters in the Danish Wadden Sea has increased dramatically between 2005 and 2007, large numbers were observed along the Swedish......The Pacific oyster (Crassostrea gigas) is an important aquaculture species world-wide. Due to its wide environmental tolerance and high growth rate, it has also become a successful invader in many areas, leading to major ecosystem changes. Low water temperatures were previously believed to restrict...

  17. Impact of an icy winter on the Pacific oyster (Crassostrea gigas Thunberg, 1793) populations in Scandinavia

    DEFF Research Database (Denmark)

    Strand, Åsa; Blanda, Elisa; Bodvin, Torjan; Davids, Jens K.; Fast Jensen, Lasse; Holm-Hansen, Tore Hejl; Hjelmert, Anders; Lindegarth, Susanne; Mortensen, Stein; Moy, Frithjof E.; Nielsen, Pernille; Norling, Pia; Nyberg, Carlo; Christensen, Helle Torp; Vismann, Bent; Wejlemann Holm, Mark; Winding Hansen, Benny; Dolmer, Per

    2012-01-01

    The Pacific oyster (Crassostrea gigas) is an invasive species that has dispersed into Scandinavia during the last few decades. The objective of this study was to evaluate the effects of extreme winter conditions on the mortality of the Pacific oyster in Scandinavia. The study was done by compiling...... sampling sites of oyster populations. Despite the severe winter conditions of 2009/2010 causing high mortality, the Pacific oyster still exists in large numbers in Scandinavia. The present investigation indicates that extreme winter conditions may result in a temporary reduction of the density of the...... Pacific oyster, but that the species can be expected to continue its invasion of Scandinavian coastal areas...

  18. Dynamique et enzymologie de la digestion chez l'huitre Crassostrea gigas

    OpenAIRE

    Boucaud, C; Lebesnerais, C; Lubet, P.; Lihrmann, I

    1983-01-01

    Chez Crassostrea gigas (Thunberg) des expériences d'alimentation contrôlée ont permis d'établir les modalités et la chronologie du transit alimentaire. Différentes activités enzymatiques en relation avec la digestion (glycosidases, esterases et peptidases) ont été localisées dans l'appareil digestif et ont permis de préciser les sites de digestion des glucides et des protides et les sites d'absorption. Un schéma explicatif des différentes étapes de la digestion est proposé.

  19. Growth of Crassostrea gasar cultured in marine and estuary environments in Brazilian waters

    OpenAIRE

    Gustavo Ruschel Lopes; Carlos Henrique Araujo de Miranda Gomes; Cláudio Rudolfo Tureck; Claudio Manuel Rodrigues de Melo

    2013-01-01

    The objective of this work was to evaluate the growth of the mangrove oyster Crassostrea gasar cultured in marine and estuarine environments. Oysters were cultured for 11 months in a longline system in two study sites - São Francisco do Sul and Florianópolis -, in the state of Santa Catarina, Southern Brazil. Water chlorophyll-α concentration, temperature, and salinity were measured weekly. The oysters were measured monthly (shell size and weight gain) to assess growth. At the end of the cult...

  20. Cloning, characterization and chromosomal location of a satellite DNA from the Pacific oyster, Crassostrea gigas

    Digital Repository Service at National Institute of Oceanography (India)

    Clabby, C.; Goswami, U.; Flavin, F.; Wilkins, N.P.; Houghton, J.A; Powell, R.

    of genetic information. Annu. Rev. Biochem. 55 (1986) 631-661. Wijers, E.R., Zijlstra, C. and Lenstra, J.A.: Rapid evolution of horse satellite DNA. Genomics 18 (1993) 113-117. Wisconsin Package: Program manual for Wisconsin Package Version 8, September... Elsevier Science B.V. All rights reserved. 0378-1119/96/$15.00 205 GENE 09452 Cloning, characterization and chromosomal location of a satellite DNA from the Pacific oyster, Crassostrea gigas (HaelII and FokI repeated DNA; tandem repetition; genomic...

  1. Peptide Induced Crystallization of Calcium Carbonate on Wrinkle Patterned Substrate: Implications for Chitin Formation in Molluscs

    Directory of Open Access Journals (Sweden)

    Ingrid M. Weiss

    2013-06-01

    Full Text Available We here present the nucleation and growth of calcium carbonate under the influence of synthetic peptides on topographically patterned poly(dimethylsiloxane (PDMS substrates, which have a controlled density of defects between the wrinkles. Experiments with two lysine-rich peptides derived from the extracellular conserved domain E22 of the mollusc chitin synthase Ar-CS1, AKKKKKAS (AS8 and EEKKKKKES (ES9 on these substrates showed their influence on the calcium carbonate morphology. A transition from polycrystalline composites to single crystalline phases was achieved with the peptide AS8 by changing the pH of the buffer solution. We analyzed three different pH values as previous experiments showed that E22 interacts with aragonite biominerals more strongly at pH 7.75 than at pH 9.0. At any given pH, crystals appeared in characteristic morphologies only on wrinkled substrates, and did not occur on the flat, wrinkle-free PDMS substrate. These results suggest that these wrinkled substrates could be useful for controlling the morphologies of other mineral/peptide and mineral/protein composites. In nature, these templates are formed enzymatically by glycosyltransferases containing pH-sensitive epitopes, similar to the peptides investigated here. Our in vitro test systems may be useful to gain understanding of the formation of distinct 3D morphologies in mollusc shells in response to local pH shifts during the mineralization of organic templates.

  2. Taste Evaluation of Non-volatile Taste Compounds in Bivalve Mollusks from Beibu Gluf, Guangxi%广西北部湾3种贝类中主要呈味物质的测定及呈味作用评价

    Institute of Scientific and Technical Information of China (English)

    陈德慰; 苏键; 刘小玲; 颜栋美; 林莹

    2012-01-01

    Major non-volatile taste active compounds in oyster (Crassostrea rivularis), clam (Meretrix meretrix) and paphia (Paphia undulata) were determined, which included free amino acids, nucleotides and so on. Taste impact of the main non-volatile taste compounds were evaluated by taste active value (TAVs) methods; umami intensity of bivalve mollusks were evaluated by equivalent umami concentration (EUC) methods. The EUC were oyster (3.2 g MSG/100 g meat), clam (1.9 g MSG/100 g meat) and paphia (2.7 g MSG/100 g meat), respectively. TAVs of all EUC were great than one, which meant they contributed to the strong umami taste of oyster, clam and paphia.%测定广西北部湾牡蛎(Crassostrea rivularis)、文蛤(Meretrix meretrix)和波纹巴非蛤(Paphia undulata)3种贝类中的呈味核苷酸(AMP、GMP、IMP)、糖原等非挥发性呈味物质的含量,并采用味道强度值和等价鲜味值(或味精当量)评价这些非挥发性呈味物质的呈味作用鲜味强度。结果表明:牡蛎、文蛤和波纹巴非蛤的味精当量分别为3.2、1.9、2.7g MSG/100g,对应的味精当量的味道强度值分别是106.7、63.3、90,均远大于1,是其呈强烈鲜味的主要原因。

  3. Maternal inheritance of mitochondrial DNA (mtDNA) in the Pacific oyster (Crassostrea gigas): a preliminary study using mtDNA sequence analysis with evidence of random distribution of MitoTracker-stained sperm mitochondria in fertilized eggs.

    Science.gov (United States)

    Obata, Mayu; Shimizu, Michiyo; Sano, Natsumi; Komaru, Akira

    2008-03-01

    In many bivalve species, paternal and maternal mitochondrial DNA (mtDNA) from sperm and eggs is transmitted to the offspring. This phenomenon is known as doubly uniparental inheritance (DUI). In these species, sperm mtDNA (M type) is inherited by the male gonad of the offspring. Egg mtDNA (F type) is inherited by both male and female somatic cells and female gonadal cells. In Mytilidae, sperm mitochondria are distributed in the cytoplasm of differentiating male germ cells because they are transmitted to the male gonad. In the present study, we investigated maternal inheritance of mtDNA in the Pacific oyster, Crassostrea gigas. Sequence analysis of two mitochondrial non-coding regions revealed an identical sequence pattern in the gametes and adductor muscle samples taken from six males and five females. To observe whether sperm mitochondria were specifically located in the cytoplasm of differentiating germ cells, their distribution was recorded in C. gigas fertilized eggs by vital staining with MitoTracker Green. Although the 1D blastomere was identified in the cytoplasm of differentiating germ cells, sperm mitochondria were located at the 1D blastomere in only 32% of eggs during the 8-cell stage. Thus, in C. gigas, sperm mitochondria do not specifically locate in the germ cell region at the 1D blastomere. We suggest that the distribution of sperm mitochondria is not associated with germ cell formation in C. gigas. Furthermore, as evidenced by the mtDNA sequences of two non-coding regions, we conclude that mitochondrial DNA is maternally inherited in this species. PMID:18393561

  4. Use of laboratory assays to predict subsequent growth and survival of Pacific oyster (Crassostrea gigas) families planted in coastal waters

    Science.gov (United States)

    Selective breeding programs for improving Pacific oyster (Crassostrea gigas) stocks are expensive, labor-intensive, and rely on lengthy field trials that are subject to stochastic outbreaks of Summer Mortality Syndrome. Laboratory assays that identify and eliminate poor-performing families prior to...

  5. Suivi de la reproduction de l'huître creuse Crassostrea gigas Secteur de Fouras 2000

    OpenAIRE

    2000-01-01

    In the framework of the actions conducted by the Ifremer for Regional Shellfish Culture Section of Ré Centre-Ouest in 2000, the DEL coastal laboratory of La Rochelle carried out a monitoring of the reproduction of the cupped oyster "Crassostrea gigas" in Fouras. This report briefly presents the obtained results.

  6. The Giant Pacific Oyster (Crassostrea gigas) as a modern analogue for fossil ostreoids

    DEFF Research Database (Denmark)

    Ullmann, Clemens Vinzenz; Böhm, Florian; Rickaby, Rosalind E.M.;

    2013-01-01

    variability is possible. Here, two shell structures of modern Giant Pacific Oysters (Crassostrea gigas), the chalky substance and foliate layers, have been sampled for trace element distributions (Mg, Sr, Mn) and stable isotope variability (C, O, Ca). Oxygen isotopes exhibit a clear seasonal signature. Mean...

  7. Transcriptome response of the Pacific oyster (Crassostrea gigas) to infection with Vibrio tubiashii using cDNA AFLP differential display

    Science.gov (United States)

    We used qualitative complementary DNA-Amplified Fragment Length Polymorphism (cDNA-AFLP) differential display analysis and real-time, quantitative PCR (RT-qPCR) to identify genes in the Pacific oyster Crassostrea gigas whose transcription either changes in response to exposure to a pathogenic bacter...

  8. Bio-accumulation kinetics of radioruthenium in marine bivalves. Laboratory study

    International Nuclear Information System (INIS)

    Three kinds of marine bivalves (wild Saccostrea cucullata, aquacultured Perna viridis and aquacultured Pinctada martens), collected from Daya Bay, the South China Sea, were used to investigate the bio-accumulation of radioruthenium in the glass aquarium with natural seawater (pH 8.20, 35 per mille salinity, filtered by 0.45 μm) at ambient temperature under laboratory feeding conditions. The experimental results show that the stead-state of biology concentration factor (BCF, ml/g) of radioruthenium was approached around 6 days for most species of bivalves. The values of BCF in shells are the highest in organs all the three bivalves. The orders of BCF values (ml x g-1) are as: Perna viridis (33.2) < Saccostrea cucullata (47.0) < Pinctada martensi (208.4) for shells and Saccostrea cucullata (1.5) < Pinctada martensi (2.2) ∼ Perma viridis (2.4) for soft tissues, respectively, after exposed for 14 days. The rate constants of uptake and elimination of radioruthenium on marine bivalves were also discussed by first-order kinetics model. The Pinctada martensi may be applicable to be an indictor for monitoring radioruthenium among the three bivalves. (author)

  9. Organohalogenated contaminants in sediments and bivalves from the Northern Arabian Gulf.

    Science.gov (United States)

    Ali, Nadeem; Ali, Lulwa Naseer; Eqani, Syed Ali Musstjab Akber Shah; Ismail, Iqbal Mohammad Ibrahim; Malarvannan, Govindan; Kadi, Mohammad W; Al-Badry Basahi, Jalal Mohammed; Covaci, Adrian

    2015-12-01

    Several classes of Organohalogenated contaminants (OHCs) were determined in sediments and bivalves collected from Kuwait coast. The levels and profile of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) were compared in both sediments and bivalves. PCB-153 and -138 were the major contributors towards total OHCs followed by DDT and its metabolites (DDTs). The higher contribution of DDTs (~40%) and BDE-47 (~15%) in bivalves as compared to that in associated sediments indicated high biota-sediment accumulation factors (BSAF). Higher BSAF (values for heavier PCBs, DDTs and PBDEs) also indicated their high accumulation potential from sediment into associated biota at most of the studied locations. Overall, OHCs in sediments and bivalves measured in current study were lower than those reported in the literature worldwide. Most of the sediment concentrations of OHCs (ng/g, dry weight) were in the range of permissible guideline values proposed by Canadian Sediment Quality Guidelines (CSQGs), with few exceptions for DDTs (5 ng/g) and PCBs (22.7 ng/g). Similarly, 10% of bivalve samples contained high levels (ng/g, lipid weight) of PCBs (300) and DDTs (150) and were above the set safety benchmarks. This study establishes baseline for future monitoring programs. PMID:26386334

  10. Organochlorine pollutants level in teleost fish and bivalve from Egyptian Mediterranean coast and Nile Estuary

    International Nuclear Information System (INIS)

    Residue levels of 15 organochlorine pollutants and 3 aroclors were analyzed by capillary Gas Chromatography GC in fish Mugil cephalus and bivalve Donax sp., collected from three different locations, at EI-Mex bay, Balteem and Rosetta. The studied pollutants were DDT's isomers, HCHs isomers as well as cyclodiene compounds, Mirex, methoxychlor, toxaphene and hexachlorobenzene (HCB), Aroclors 1248, 1254 and 1260 in addition to 10 individual PCBs congeners. Lipid content percentage ranged from 2.2 to 3.6% in fish and 1.0 to 1.5 % in bivalve, as judged by extractable Organic Matter (EOM) values. Lindane dominated the alph-isomer, with highest concentration 4.6 ng/g in fish from EI-Mex. p,p'-DDE dominated other DDTs analogs with the highest concentrations in fish 15.6 ng/g) and bivalve (9.9 ng/g) from Rosetta. Toxaphene was detected in all locations with maximum levels 13.0 and 11.0 ng/g in bivalve and fish respectively, from Rosetta. Aroclor 1248 dominated other aroclors in both fish and bivalve. For individual PCBs 153 congener dominated other congeners with lower chlorinated biphenyls (mono-through penta-chloro-biphenyls) congeners occurred at lower levels except PCB 200 and PCB 206. (author)

  11. Taxonomic Study of Edible Bivalve from Selected Division of Sarawak, Malaysia

    Directory of Open Access Journals (Sweden)

    M.K. Abu Hena

    2012-01-01

    Full Text Available The diversity of edible bivalve was conducted from August 2010 to July 2011 covering eight divisions i.e., Kuching, Sarikei, Sibu, Mukah, Bintulu, Miri, Limbang and Lawas of Sarawak, Malaysia. Samples were collected from native market and fishing village during the study period. All edible bivalves inhabit either in brackish or marine environment and comprised 19 species from 10 families namely Meretrix meretrix, M. lyrata, Paphia undulata, Circe scripta, Solen regularies, Solen lamarckii, Pharella acutidens, Amusium pleuronectes, Anadara granosa, Pholas orientalis, Gluconome virens, Placuna placenta, Crassotrea lugubris, Isognomon ephippium, Polymesoda erosa, P. bengalensis, P. expansa, Anadonta woodina and Pilsbryoconcha exilis. The diversity of edible bivalves was found highest in Kuching and Bintulu compared to other divisions studied in Sarawak. The bivalve species at Sarawak could have economic potentiality in terms of protein source, livelihoods of local tribes and economic value. Study suggests that if the high conservation and management of edible bivalve diversity could establish in the coastal and wetland area of Sarawak, a remarkable and vast economic return could achieve.

  12. Postglacial floodings of the Marmara Sea: molluscs and sediments tell the story

    Science.gov (United States)

    Büyükmeriç, Yeşim

    2016-08-01

    The early Holocene marine flooding of the Black Sea has been the subject of intense scientific debate since the "Noah's Flood" hypothesis was proposed in the late 1990s. The chronology of the flooding is not straightforward because the connection between the Black Sea and the Mediterranean Sea involves the intermediate Marmara Sea Basin via two sills (Dardanelles and Bosphorus). This study explores the chronology of late Pleistocene-Holocene flooding by examining sedimentary facies and molluscs from 24 gravity cores spanning shelf to slope settings in the southern Marmara Sea Basin. A late Pleistocene Ponto-Caspian (Neoeuxinian) mollusc association is found in 12 of the cores, comprising 14 mollusc species and dominated by brackish (oligohaline-lower mesohaline) endemic taxa (dreissenids, hydrobiids). The Neoeuxinian association is replaced by a Turritella- Corbula association at the onset of the Holocene. The latter is dominated by marine species, several of which are known to thrive under dysoxic conditions in muddy bottoms. This association is common in early Holocene intervals as well as sapropel intervals in younger Holocene strata. It is an indicator of low-salinity outflows from the Black Sea into the Marmara Sea that drive stratification. A marine Mediterranean association (87 species) represents both soft bottom and hard substrate faunas that lived in well-ventilated conditions and upper mesohaline-polyhaline salinities (ca. 25 psu). Shallower areas were occupied by hard substrate taxa and phytopdetritic communities, whereas deeper areas had soft bottom faunas. The middle shelf part of the northern Gemlik Gulf has intervals with irregular and discontinuous sedimentary structures admixed with worn Neoeuxinian and euryhaline Mediterranean faunas. These intervals represent reworking events (slumping) likely related to seismic activity rooted in the North Anatolian Fault system. The core data and faunas indicate an oscillating postglacial sea-level rise and

  13. Postglacial floodings of the Marmara Sea: molluscs and sediments tell the story

    Science.gov (United States)

    Büyükmeriç, Yeşim

    2016-08-01

    The early Holocene marine flooding of the Black Sea has been the subject of intense scientific debate since the "Noah's Flood" hypothesis was proposed in the late 1990s. The chronology of the flooding is not straightforward because the connection between the Black Sea and the Mediterranean Sea involves the intermediate Marmara Sea Basin via two sills (Dardanelles and Bosphorus). This study explores the chronology of late Pleistocene-Holocene flooding by examining sedimentary facies and molluscs from 24 gravity cores spanning shelf to slope settings in the southern Marmara Sea Basin. A late Pleistocene Ponto-Caspian (Neoeuxinian) mollusc association is found in 12 of the cores, comprising 14 mollusc species and dominated by brackish (oligohaline-lower mesohaline) endemic taxa (dreissenids, hydrobiids). The Neoeuxinian association is replaced by a Turritella- Corbula association at the onset of the Holocene. The latter is dominated by marine species, several of which are known to thrive under dysoxic conditions in muddy bottoms. This association is common in early Holocene intervals as well as sapropel intervals in younger Holocene strata. It is an indicator of low-salinity outflows from the Black Sea into the Marmara Sea that drive stratification. A marine Mediterranean association (87 species) represents both soft bottom and hard substrate faunas that lived in well-ventilated conditions and upper mesohaline-polyhaline salinities (ca. 25 psu). Shallower areas were occupied by hard substrate taxa and phytopdetritic communities, whereas deeper areas had soft bottom faunas. The middle shelf part of the northern Gemlik Gulf has intervals with irregular and discontinuous sedimentary structures admixed with worn Neoeuxinian and euryhaline Mediterranean faunas. These intervals represent reworking events (slumping) likely related to seismic activity rooted in the North Anatolian Fault system. The core data and faunas indicate an oscillating postglacial sea-level rise and

  14. Postglacial floodings of the Marmara Sea: molluscs and sediments tell the story

    Science.gov (United States)

    Büyükmeriç, Yeşim

    2016-03-01

    The early Holocene marine flooding of the Black Sea has been the subject of intense scientific debate since the "Noah's Flood" hypothesis was proposed in the late 1990s. The chronology of the flooding is not straightforward because the connection between the Black Sea and the Mediterranean Sea involves the intermediate Marmara Sea Basin via two sills (Dardanelles and Bosphorus). This study explores the chronology of late Pleistocene-Holocene flooding by examining sedimentary facies and molluscs from 24 gravity cores spanning shelf to slope settings in the southern Marmara Sea Basin. A late Pleistocene Ponto-Caspian (Neoeuxinian) mollusc association is found in 12 of the cores, comprising 14 mollusc species and dominated by brackish (oligohaline-lower mesohaline) endemic taxa (dreissenids, hydrobiids). The Neoeuxinian association is replaced by a Turritella-Corbula association at the onset of the Holocene. The latter is dominated by marine species, several of which are known to thrive under dysoxic conditions in muddy bottoms. This association is common in early Holocene intervals as well as sapropel intervals in younger Holocene strata. It is an indicator of low-salinity outflows from the Black Sea into the Marmara Sea that drive stratification. A marine Mediterranean association (87 species) represents both soft bottom and hard substrate faunas that lived in well-ventilated conditions and upper mesohaline-polyhaline salinities (ca. 25 psu). Shallower areas were occupied by hard substrate taxa and phytopdetritic communities, whereas deeper areas had soft bottom faunas. The middle shelf part of the northern Gemlik Gulf has intervals with irregular and discontinuous sedimentary structures admixed with worn Neoeuxinian and euryhaline Mediterranean faunas. These intervals represent reworking events (slumping) likely related to seismic activity rooted in the North Anatolian Fault system. The core data and faunas indicate an oscillating postglacial sea-level rise and

  15. Preliminary estimates of growth parameters for three commercial bivalve species of Peru (Gari solida, Anlacomya ater and Semele solida)

    OpenAIRE

    Urban, H. J.

    1991-01-01

    The parameters of the von Bertalanffy growth equation were estimated, mainly from size-frequency data, for three commercially exploited Peruvian bivalves, Gari solida, Aulacomya ater and Semele solida, collected by divers from "Bahia de Independencia", Pisco, Peru from November 1986 to September 1987 and from January to September 1990. Some related information on the three bivalves in question are also presented.

  16. The influence of sediment, food and organic ligands on the uptake of copper by sediment-dwelling bivalves

    NARCIS (Netherlands)

    Absil, M.C.P.; Berntssen, M.; Gerringa, L.J.A.

    1996-01-01

    The sediment-dwelling bivalve Macoma balthica was exposed to dissolved copper ina flow-through system in long-term experiments. Unlike another sediment-dwelling bivalve, the suspension feeder Cerastoderma edule (cockle), M. balthica accumulated copper from the sediment, while the cockles did not. Wh

  17. In situ method for measurements of community clearance rate on shallow water bivalve populations

    DEFF Research Database (Denmark)

    Hansen, Benni W.; Dolmer, Per; Vismann, Bent

    2011-01-01

    air lift connected to a SCUBA diver pressure tank generating a continuous and gentle water circulation. This ensures a complete mixture of suspended particles, and thereby, a maximum filtration by the bivalves. An in situ fluorometer was mounted to record plant pigment reduction due to mussel...... clearance in real-time. To calibrate the in situ fluorometer triplicate water samples were obtained initially in each of the bivalve filtration measurements. The water samples were filtrated, extracted, and later analyzed for plant pigment concentration on a laboratory spectrophotometer. The main conclusion......An open-top chamber was designed for measuring ambient community clearance rate on undisturbed bivalve populations in the field. The chamber was pressed 5-10 cm down in the sediment on the mussel bed. It holds approximately 30-40 cm water column equal to a volume of 43-77 L. It was provided with an...

  18. Dioxin-like chemicals in bivalves and sediment collected from around Australia

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, J.F.; Muller, R.; Goudkamp, K. [EnTox, The University of Queensland, Brisbane (AU)] (and others)

    2004-09-15

    The aquatic environment is a significant sink for persistent organic pollutants including dioxin-like chemicals. Besides continuous investigations into sources of higher chlorinated PCDD that have initially been found in soils, and later in dugong and sediments little is known about the levels of dioxin-like chemicals in Australia's aquatic environment. In 2002 the National Dioxin Program (NDP) was commissioned by the Department of Environment and Heritage, Australia. One focus of the NDP was to evaluate background levels of dioxin-like chemicals in Australia's environment. One component of the 'Environmental Levels' project aimed to identify dioxinlike chemicals in the aquatic environment including bivalves collected in both marine, estuarine and freshwater systems. Here we report results from the NDP aquatic study with a particular emphasis on the levels of dioxin-like chemicals in bivalves and sediments respectively in areas from where the bivalves were collected.

  19. Saturation-state sensitivity of marine bivalve larvae to ocean acidification

    Science.gov (United States)

    Waldbusser, George G.; Hales, Burke; Langdon, Chris J.; Haley, Brian A.; Schrader, Paul; Brunner, Elizabeth L.; Gray, Matthew W.; Miller, Cale A.; Gimenez, Iria

    2015-03-01

    Ocean acidification results in co-varying inorganic carbon system variables. Of these, an explicit focus on pH and organismal acid-base regulation has failed to distinguish the mechanism of failure in highly sensitive bivalve larvae. With unique chemical manipulations of seawater we show definitively that larval shell development and growth are dependent on seawater saturation state, and not on carbon dioxide partial pressure or pH. Although other physiological processes are affected by pH, mineral saturation state thresholds will be crossed decades to centuries ahead of pH thresholds owing to nonlinear changes in the carbonate system variables as carbon dioxide is added. Our findings were repeatable for two species of bivalve larvae could resolve discrepancies in experimental results, are consistent with a previous model of ocean acidification impacts due to rapid calcification in bivalve larvae, and suggest a fundamental ocean acidification bottleneck at early life-history for some marine keystone species.

  20. Sequestration of dietary alkaloids by the spongivorous marine mollusc Tylodina perversa.

    Science.gov (United States)

    Thoms, Carsten; Ebel, Rainer; Hentschel, Ute; Proksch, Peter

    2003-01-01

    Specimens of the spongivorous Mediterranean opisthobranch Tylodina perversa that had been collected while feeding on Aplysina acerophoba were shown to sequester the brominated isoxazoline alkaloids of their prey. Alkaloids were stored in the hepatopancreas, mantle tissues, and egg masses in an organ-specific manner. Surprisingly, the known sponge alkaloid aerothionin which is found only in A. cavernicola but not in A. aerophoba was also among the metabolites identified in wild caught specimens of T. perversa as well as in opisthobranchs with a documented feeding history on A. aerophoba. Mollusc derived aerothionin is postulated to be derived from a previous feeding encounter with A. cavernicola as T. perversa was found to freely feed on both Aplysina sponges in aquarium bioassays. The possible ecological significance of alkaloid sequestration by T. perversa is still unknown. PMID:12872940

  1. Intermittent hypoxia leads to functional reorganization of mitochondria and affects cellular bioenergetics in marine molluscs.

    Science.gov (United States)

    Ivanina, Anna V; Nesmelova, Irina; Leamy, Larry; Sokolov, Eugene P; Sokolova, Inna M

    2016-06-01

    Fluctuations in oxygen (O2) concentrations represent a major challenge to aerobic organisms and can be extremely damaging to their mitochondria. Marine intertidal molluscs are well-adapted to frequent O2 fluctuations, yet it remains unknown how their mitochondrial functions are regulated to sustain energy metabolism and prevent cellular damage during hypoxia and reoxygenation (H/R). We used metabolic control analysis to investigate the mechanisms of mitochondrial responses to H/R stress (18 h at recovery, combined with the ability to suppress ATP-demanding cellular functions during hypoxia, may contribute to high resilience of clams to H/R stress and help maintain energy homeostasis during frequent H/R cycles in the intertidal zone. PMID:27252455

  2. Self-similar mesostructure evolution of the growing mollusc shell reminiscent of thermodynamically driven grain growth

    Science.gov (United States)

    Bayerlein, Bernd; Zaslansky, Paul; Dauphin, Yannicke; Rack, Alexander; Fratzl, Peter; Zlotnikov, Igor

    2014-12-01

    Significant progress has been made in understanding the interaction between mineral precursors and organic components leading to material formation and structuring in biomineralizing systems. The mesostructure of biological materials, such as the outer calcitic shell of molluscs, is characterized by many parameters and the question arises as to what extent they all are, or need to be, controlled biologically. Here, we analyse the three-dimensional structure of the calcite-based prismatic layer of Pinna nobilis, the giant Mediterranean fan mussel, using high-resolution synchrotron-based microtomography. We show that the evolution of the layer is statistically self-similar and, remarkably, its morphology and mesostructure can be fully predicted using classical materials science theories for normal grain growth. These findings are a fundamental step in understanding the constraints that dictate the shape of these biogenic minerals and shed light on how biological organisms make use of thermodynamics to generate complex morphologies.

  3. Sperm tail differentiation in the nudibranch mollusc Hypselodoris tricolor (Gastropoda, Opisthobranchia).

    Science.gov (United States)

    Medina, A; Moreno, F J; García-Herdugo, G

    1988-06-01

    The sperm axoneme of Hypselodoris tricolor forms from a single centriole that is located initially beneath the plasma membrane and then migrates to the nuclear surface. A conspicuous centriolar adjunct-like formation is present in the neck of midspermatids, but it becomes very reduced at the end of spermiogenesis. In spermatocyte and spermatid mitochondria, intracristal bodies originate from the accumulation of a dense material in some cristae. From our observations and foregoing reports, it may be concluded that the process of sperm tail differentiation in opisthobranchs resembles that in pulmonates, whereas it differs in many respects from that occurring in prosobranchs. The appearance of intracristal bodies in modified mitochondria seems to be a special feature of spermatogenesis in the opisthobranchs that does not occur in the two other groups of gastropod molluscs. PMID:3235038

  4. Organic membranes determine the pattern of the columnar prismatic layer of mollusc shells.

    Science.gov (United States)

    Checa, Antonio G; Macías-Sánchez, Elena; Harper, Elizabeth M; Cartwright, Julyan H E

    2016-05-11

    The degree to which biological control is exercised compared to physical control of the organization of biogenic materials is a central theme in biomineralization. We show that the outlines of biogenic calcite domains with organic membranes are always of simple geometries, while without they are much more complex. Moreover, the mineral prisms enclosed within the organic membranes are frequently polycrystalline. In the prismatic layer of the mollusc shell, organic membranes display a dynamics in accordance with the von Neumann-Mullins and Lewis Laws for two-dimensional foam, emulsion and grain growth. Taken together with the facts that we found instances in which the crystals do not obey such laws, and that the same organic membrane pattern can be found even without the mineral infilling, our work indicates that it is the membranes, not the mineral prisms, that control the pattern, and the mineral enclosed within the organic membranes passively adjusts to the dynamics dictated by the latter. PMID:27147096

  5. Morphometric Studies on Anodonta Anatine Bivalve Population from the Dognecea Lake

    Directory of Open Access Journals (Sweden)

    Marian Bura

    2011-10-01

    Full Text Available In the Dognecea Lake, near town Bocsa in Caras-Severin county a strong bivalve population has been discovered from the duck mussel specie (Anodonta anatina. Harvested individuals were transported to the Aquaculture laboratory where measurements and correct identification was made. This specie is considered endangered but in Banat area, especially in the Dognecea Lake it is well represented, having an ecological importance, but the bivalve can have an economical importance too, due to the high percentage of edible part of 56.5%.

  6. Conus: first comprehensive conservation red list assessment of a marine gastropod mollusc genus.

    Directory of Open Access Journals (Sweden)

    Howard Peters

    Full Text Available Marine molluscs represent an estimated 23% of all extant marine taxa, but research into their conservation status has so far failed to reflect this importance, with minimal inclusion on the authoritative Red List of the International Union for the Conservation of Nature (IUCN. We assessed the status of all 632 valid species of the tropical marine gastropod mollusc, Conus (cone snails, using Red List standards and procedures to lay the groundwork for future decadal monitoring, one of the first fully comprehensive global assessments of a marine taxon. Three-quarters (75.6% of species were not currently considered at risk of extinction owing to their wide distribution and perceived abundance. However, 6.5% were considered threatened with extinction with a further 4.1% near threatened. Data deficiency prevented 13.8% of species from being categorised although they also possess characteristics that signal concern. Where hotspots of endemism occur, most notably in the Eastern Atlantic, 42.9% of the 98 species from that biogeographical region were classified as threatened or near threatened with extinction. All 14 species included in the highest categories of Critically Endangered and Endangered are endemic to either Cape Verde or Senegal, with each of the three Critically Endangered species restricted to single islands in Cape Verde. Threats to all these species are driven by habitat loss and anthropogenic disturbance, in particular from urban pollution, tourism and coastal development. Our findings show that levels of extinction risk to which cone snails are exposed are of a similar magnitude to those seen in many fully assessed terrestrial taxa. The widely held view that marine species are less at risk is not upheld.

  7. The effects of temperature on oxygen uptake and nutrient flux in sediment inhabited by molluscs

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2013-02-01

    Full Text Available Benthic invertebrates play important roles in oxygen uptake and nutrient cycling in the benthic boundary layer. Temperature is an important factor that influences both invertebrate activity and the effects of the bioturbation on biogeochemistry. The present study aimed to investigate the influence of temperature on the sediment oxygen uptake and nutrient flux across the sediment-water interface in sediment inhabited by molluscs, animals that often dominate the benthic community. A microcosm was constructed using sediment, lake water, and molluscs from Lake Taihu, China. The clam Corbicula fluminea (Bivalvia: Corbiculidae and the snail Bellamya aeruginosa (Gastropoda: Viviparidae were selected for the experiment because they dominate the benthic community in the lake. The effect of C. fluminea and B. aeruginosa on sediment oxygen uptake and nutrient flux was simultaneously examined at both 15 and 25℃. The results indicated that C. fluminea significantly increased the sediment oxygen uptake and release of soluble reactive phosphorus (SRP and ammonium from the sediment to the overlying water at both temperatures, and the net sediment oxygen uptake, and the net SRP and ammonium fluxes caused by the clams were significantly higher at 25℃ than at 15℃. Moreover, B. aeruginosa significantly increased the sediment oxygen uptake at the two experimental temperatures, however the net sediment oxygen uptake induced by the snail did not differ significantly between 15 and 25℃. The SRP released from the sediment was stimulated significantly by B. aeruginosa at 25℃, and B. aeruginosa also produced significantly more net SRP release at 25℃ than that at 15℃. In contrast, the influence of B. aeruginosa on the net ammonium flux at each temperature was not statistically significant.

  8. CYP1A-immunopositive proteins in bivalves identified as cytoskeletal and major vault proteins

    DEFF Research Database (Denmark)

    Grøsvik, Bjørn Einar; Jonsson, Henrik; Rodríguez-Ortega, Manuel J;

    2006-01-01

    To identify possible CYP1A-immunopositive proteins in bivalves, we used anti-fish CYP1A antibodies combined with one- and two-dimensional gel electrophoresis and mass spectrometry, and found that two of the main CYP1A-immunopositive proteins in digestive gland of Mytilus edulis, were cytoskeletal...

  9. 210Po, 40K activity concentrations in bivalves collected along the Southern Coastal from Spain

    International Nuclear Information System (INIS)

    The levels of 210Po and 40K were determined in several species of bivalves growing along the coast of the region of Andalusia (southern Spain) during 2005. A network sampling of 30 points was designed and the 5 species more consumed were selected, in order to obtain the base line (background) of these species. Once the bivalve samples were lyophilized, the natural radionuclides were measured by both alpha-particle spectrometry (210Po) and gamma spectrometry (40K), being 40K the only one radionuclide detected by gamma spectrometry. Several variables like type of water (Atlantic Ocean vs Mediterranean Sea), bivalve specie, percentage of water (dry weight/wet weight relation), and the geographical distribution have been studied in relation to activity concentrations of natural radionuclides. The values of the activity concentrations between the different species and the origin of waters (atlantics or mediterranean) were not statistically significant. The activity concentrations of 210Po varied between 85 ± 4 Bq kg-1 (d.w., dry weight) and 648 ± 22 Bq kg-1 (d.w.) (Average = 250 ± 121 Bq kg-1), while 40K activity concentrations ranged from 357 ± 28 to 817 ± 48 Bq kg-1 (d.w.) (Average = 522 ± 114 Bq kg-1). On the other hand, and due to the high consume rates of bivalves in the coastal populations, the dosimetric implications of the 210Po activity concentrations found in the study have been also evaluated. (author)

  10. Bivalve grazing, nutrient cycling and phytoplankton dynamics in an estuarine ecosystem.

    NARCIS (Netherlands)

    Prins, T.C.

    1996-01-01

    This thesis has considered the impact of the suspension feeding bivalve Mytilusedulis on nutrient cycling and phytoplankton in an estuarine ecosystem. The research was started within the framework of an extensive research project with the objective to evaluate the changes in the Oosterschelde ecosys

  11. Nutritional and reproductive strategies in a chemosymbiotic bivalve living in a tropical intertidal seagrass bed

    NARCIS (Netherlands)

    van der Geest, M.; Sall, A.A.; Ely, S.O.; Nauta, R.W.; van Gils, J.A.; Piersma, T.

    2014-01-01

    Sulphide-oxidizing endosymbiont-bearing bivalves often dominate the infauna of seagrass-covered sediments, where they control sulphide levels and contribute to carbon cycling by feeding on chemosynthetically fixed carbon and suspended particulate organic matter (SPOM). Previous studies from temperat

  12. Nutritional and reproductive strategies in a chemsoymbiotic bivalve living in a tropical intertidal seagrass bed

    NARCIS (Netherlands)

    van der Geest, Matthijs; Sall, Amadou Abderahmane; Ely, SIdi Ould; Nauta, Reindert W.; Gils, Jan A. van; Piersma, Theunis

    2014-01-01

    Sulphide-oxidizing endosymbiont-bearing bivalves often dominate the infauna of seagrass-covered sediments, where they control sulphide levels and contribute to carbon cycling by feeding on chemosynthetically fixed carbon and suspended particulate organic matter (SPOM). Previous studies from temperat

  13. Wood-Boring Bivalves (Mollusca: Teredinidae, Pholadidae) of Pacific coast of Colombia

    International Nuclear Information System (INIS)

    Twelve species of wood-boring bivalves, ten of the family Teredinidae and two of family Pholadidae were collected in mangroves at 6 locations of the Pacific coast of Colombia. This paper presents a brief description of these species, including size, ecological notes and geographical distribution.

  14. Novas ocorrências de gastrópodes e bivalves marinhos no Brasil (Mollusca

    Directory of Open Access Journals (Sweden)

    Absalão Ricardo Silva

    2003-01-01

    Full Text Available The gastropods Costaclis egregia (Dall, 1889, Thaleia nisonis (Dall, 1889, Tjaernoeia michaeli Engl, 2001 and the bivalves Bathyarca sp., Myonera aff. ruginosa (Jeffreys, 1882 are recorded for the first time in Brazilian waters. This paper presents a brief description of these species and also include ilustrations.

  15. 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. PMID:25017714

  16. Modiolarca lateralis (Pteryomorphia: Mytilidae: bivalve associated to six species of ascidians from Bocas del Toro, Panama

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    Juan I Cañete

    2013-11-01

    Full Text Available We describe the presence of the bivalve Modiolarca lateralis (Say, 1822 in six tropical ascidians Ascidia curvata, A. sydneiensis, A. panamensis, A. interrupta, Herdmania pallida and Polycarpa spongiabilis collected at depths of 1-3 m on coral reefs, mangrove roots and dock supports in Almirante Bay, Bocas del Toro, Panama (9°18'N, 82°13'W during June-July 2011. Bivalve prevalence varied between 9-30% across species, but was mainly associated with A. panamensis, P. spongiabilis and A. interrupta. Prevalence seems to be influenced by tunic thickness rather than by the ascidian size. Bivalves varied in size (0.6-11 mm shell length, with the smallest individual found in A. sydneiensis. There were only one or two bivalves per ascidians, although a maximum of 18 was found in one A. panamensis. M. lateralis seems to behave similarly to its temperate counterparts: it has a variety of hosts, occurs mainly in the anterior region of the ascidians, and has a variable abundance per host.

  17. Accumulation, Toxicity And Elimination Of 60Co In Some Aquatic Bivalves

    International Nuclear Information System (INIS)

    The present study was undertaken to evaluate the importance of some common bivalve oysters namely Caelatura teretiusculua and Caelatura companyoi as new radiobioindicators for 60Co in Egyptian aquatic environment.The uptake and accumulation of 60Co in water were followed for four weeks to evaluate the following:1-Maximum uptake as concentration factor values.2-The rate of survival of bivalves at different activity levels of 60Co to estimate its toxic effect.3-The lethal dose (LD50) of 60Co.4-The effect of ph of 60Co polluted water on survival of biota.5-The competitive effects of Zn+2 and Fe+3 with 60Co on the uptake and accumulation.6-The effect of biota weight on the uptake of 60Co.7-Elimination of the accumulated 60Co by such biota in water and in 10-4M ethylene diamine tetra acetic acid (EDTA) as chelating agent that enhance the bivalve to release the accumulated radioisotope.The results showed that 60Co was highly taken up by the investigated biota with high concentration factor values and that EDTA enhanced the decontamination of 60Co than water. It could be concluded that the investigated bivalves can be used as good radiobioindicators for pollution of water with 60Co.

  18. Study of the U and Th series in Crassostrea mangle shell

    International Nuclear Information System (INIS)

    Foraminifera, corals and mollusks shells have been used as proxies for environmental, paleoenvironmental and climatic change studies in marine system by using elemental and isotopic ratios as recorder of such events. Nevertheless, there is little information available on the U and Th radionuclides decay series applied on those fields. In this sense, the objective of this paper was to evaluate the activity concentrations of the U and Th nuclide decay series in Crassostrea mangle shell samples as a function of the geographic location. Samples from Sao Paulo, Parana, Alagoas, Rio Grande do Norte and Pernambuco states were analyzed by Neutron Activation Analysis and Gross Alpha and Beta Counting. Statistical analysis applied to the obtained results allowed differencing samples coming from Sao Paulo from that coming from Parana. (author)

  19. Moderate establishment success of Pacific oyster, Crassostrea gigas, on a sheltered intertidal mussel bed

    DEFF Research Database (Denmark)

    Holm, M.W.; Davids, J.K.; Dolmer, Per;

    2015-01-01

    The Pacific oyster (Crassostrea gigas Thunberg 1793) is introduced into marine ecosystems worldwide. In Denmark, C. gigas was introduced into the micro tidal Limfjord, around 1972 for aquaculture. This study describes the population structure of C. gigas at Agger Tange in 2007, 2009, 2010 and 2011....... Here, C. gigas use beds of Blue mussels (Mytilus edulis L.) as primary habitat. The mean abundance (±1 SD) of C. gigas was unchanged during our study (45±2indv.m-2), while it increased for M. edulis from 2010 to 2011 (934±610 to 1434±750indv.m-2, respectively). In 2009, a newly settled cohort of C....... gigas was present, but in the succeeding years no or negligible recruitment was recorded. However, age cohort analyses, based on individual shell size at different ages, suggest successful recruitment in three out of seven years. A comparison with the course of the bioinvasion in List Tidal Basin...

  20. Paleoclimatic reconstructions of the northern Red Sea during the Holocene inferred from stable isotope records of modern and fossil corals and molluscs.

    OpenAIRE

    Moustafa, Y.

    2000-01-01

    Fossil corals and molluscs from elevated and submerged reef terraces of the western Gulf of Aqaba (northern Red Sea) document Holocene climate changes in the northern Red Sea. The stable isotopic composition of oxygen and carbon in massive modern and fossil corals (Porites spp.) and also in modern and fossil molluscs (Tridacna spp.) is used to reconstruct the past climatic and oceanographic changes during the Holocene in the northern Red Sea and the Gulf of Aqaba.

  1. Influence of hydro-sedimentary factors on mollusc death assemblages in a temperate mixed tide-and-wave dominated coastal environment: Implications for the fossil record

    OpenAIRE

    Poirier, Clement; Sauriau, Pierre-Guy; Chaumillon, Eric; Bertin, Xavier

    2010-01-01

    Mollusc death assemblages were recovered in 98 subtidal sampling stations on the seafloor of the shallow Pertuis Charentais Sea (Atlantic coast of France). Taxonomic composition and spatial distribution of death assemblages were investigated, as well as their response to sediment grain size (field data), bottom shear stress (coupled tide and wave hydrodynamic modelling), and sediment budget (bathymetric difference map) Results showed that molluscs are likely to be reliable paleoenvironmental ...

  2. Late Paleocene Arctic Ocean shallow-marine temperatures from mollusc stable isotopes

    Science.gov (United States)

    Bice, Karen L.; Arthur, Michael A.; Marincovich, Louie, Jr.

    1996-01-01

    Late Paleocene high-latitude (80°N) Arctic Ocean shallow-marine temperatures are estimated from molluscan δ18O time series. Sampling of individual growth increments of two specimens of the bivalve Camptochlamys alaskensis provides a high-resolution record of shell stable isotope composition. The heavy carbon isotopic values of the specimens support a late Paleocene age for the youngest marine beds of the Prince Creek Formation exposed near Ocean Point, Alaska. The oxygen isotopic composition of regional freshwater runoff is estimated from the mean δ18O value of two freshwater bivalves collected from approximately coeval fluviatile beds. Over a 30 – 34‰ range of salinity, values assumed to represent the tolerance of C. alaskensis, the mean annual shallow-marine temperature recorded by these individuals is between 11° and 22°C. These values could represent maximum estimates of the mean annual temperature because of a possible warm-month bias imposed on the average δ18O value by slowing or cessation of growth in winter months. The amplitude of the molluscan δ18O time series probably records most of the seasonality in shallow-marine temperature. The annual temperature range indicated is approximately 6°C, suggesting very moderate high-latitude marine temperature seasonality during the late Paleocene. On the basis of analogy with modern Chlamys species, C. alaskensis probably inhabited water depths of 30–50 m. The seasonal temperature range derived from δ18O is therefore likely to be damped relative to the full range of annual sea surface temperatures. High-resolution sampling of molluscan shell material across inferred growth bands represents an important proxy record of seasonality of marine and freshwater conditions applicable at any latitude. If applied to other regions and time periods, the approach used here would contribute substantially to the paleoclimate record of seasonality.

  3. A glycoprotein in shells of conspecifics induces larval settlement of the Pacific oyster Crassostrea gigas.

    Directory of Open Access Journals (Sweden)

    Hebert Ely Vasquez

    Full Text Available Settlement of larvae of Crassostrea gigas on shell chips (SC prepared from shells of 11 different species of mollusks was investigated. Furthermore, the settlement inducing compound in the shell of C. gigas was extracted and subjected to various treatments to characterize the chemical cue. C. gigas larvae settled on SC of all species tested except on Patinopecten yessoensis and Atrina pinnata. In SC of species that induced C. gigas larvae to settle, settlement was proportionate to the amount of SC supplied to the larvae. When compared to C. gigas SC, all species except Crassostrea nippona showed lower settlement inducing activities, suggesting that the cue may be more abundant or in a more available form to the larvae in shells of conspecific and C. nippona than in other species. The settlement inducing activity of C. gigas SC remained intact after antibiotic treatment. Extraction of C. gigas SC with diethyl ether (Et2O-ex, ethanol (EtOH-ex, and water (Aq-ex did not induce larval settlement of C. gigas larvae. However, extraction of C. gigas SC with 2N of hydrochloric acid (HCl-ex induced larval settlement that was at the same level as the SC. The settlement inducing compound in the HCl-ex was stable at 100°C but was destroyed or degraded after pepsin, trypsin, PNGase F and trifluoromethanesulfonic acid treatments. This chemical cue eluted between the molecular mass range of 45 and 150 kDa after gel filtration and revealed a major band at 55 kDa on the SDS-PAGE gel after staining with Stains-all. Thus, a 55 kDa glycoprotein component in the organic matrix of C. gigas shells is hypothesized to be the chemical basis of larval settlement on conspecifics.

  4. Depth-related gradients in community structure and relatedness of bivalves and isopods in the Southern Ocean

    Science.gov (United States)

    Brandt, Angelika; Linse, Katrin; Ellingsen, Kari E.; Somerfield, Paul J.

    2016-05-01

    Despite increased research over the last decade, diversity patterns in Antarctic deep-sea benthic taxa and their driving forces are only marginally known. Depth-related patterns of diversity and distribution of isopods and bivalves collected in the Atlantic sector of the Southern Ocean are analysed. The data, sampled by epibenthic sledge at 40 deep-sea stations from the upper continental slope to the hadal zone (774-6348 m) over a wide area of the Southern Ocean, comprises 619 species of isopods and 81 species of bivalves. There were more species of isopods than bivalves in all samples, and species per station varied from 2 to 85 for isopods and from 0 to 18 for bivalves. Most species were rare, with 72% of isopod species restricted to one or two stations, and 45% of bivalves. Among less-rare species bivalves tended to have wider distributions than isopods. The species richness of isopods varied with depth, showing a weak unimodal curve with a peak at 2000-4000 m, while the richness of bivalves did not. Multivariate analyses indicate that there are two main assemblages in the Southern Ocean, one shallow and one deep. These overlap over a large depth-range (2000-4000 m). Comparing analyses based on the Sørensen resemblance measure and Γ+ (incorporating relatedness among species) indicates that rare species tend to have other closely related species within the same depth band. Analysis of relatedness among species indicates that the taxonomic variety of bivalves tends to decline at depth, whereas that of isopods is maintained. This, it is speculated, may indicate that the available energy at depth is insufficient to maintain a range of bivalve life-history strategies.

  5. Měkkýši PR Velké Doly u Českého Těšína (Slezsko, Česká republika Molluscs of the Velké Doly Natural Reserve near the town of Český Těšín (Silesia, Czech Republic

    Directory of Open Access Journals (Sweden)

    Jiří Kupka

    2006-09-01

    Full Text Available The molluscan fauna of the Velké Doly Natural Reserve was surveyed in 1999 and 2006. In total, 27 snail species were found (26 terrestrial gastropods and 1 bivalve. The Natural Reserve is only 1.5 km far from ironworks “Třinecké železárny”. In the 18th century, there was a limestone quarry and beech plantation (as a fuel for ironworks in the reserve. At the present time the reserve represents the secondary forests society Tilio cordatae-Carpinetum with protected and regional notable plants in undergrowth (Cephalanthera damasonium, Lilium martagon, Arum alpinum, Hacquetia epipactis, etc. The present character of the Velké Doly Natural Reserve is a result of human activities, nevertheless it is preserved and favourable site for molluscs, since many stenotopic and endangered woodland species occur there (e.g. Discus perspectivus, Petasina unidentata, Oxychilus glaber. The presence of the vulnerable snail Discus perspectivus is notable as first locality in Poland part of Těšín region (the Natural Reserve Velké Doly is located on the Poland border. Occurrence of euryecious species Arion distinctus, Arion lusitanicus and Limax maximus could relate with some human impact (e.g. presence of allotted gardens colony.

  6. An overview of chemosynthetic symbioses in bivalves from the North Atlantic and Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    S. Duperron

    2013-05-01

    Full Text Available Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria that ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, eastern Americas, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous, more easily accessible shallow marine species have been studied. Herein we provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east from the Gulf of Mexico to the Sea of Marmara, and north-to-south from the Arctic to the Gulf of Guinea. Characteristics of symbioses in 53 species from the area are summarized for each of the five bivalve families documented to harbor chemosynthetic symbionts (Mytilidae, Vesicomyidae, Solemyidae, Thyasiridae and Lucinidae. Comparisons are made between the families, with special emphasis on ecology, life cycle, and connectivity. Chemosynthetic symbioses are a major adaptation to ecosystems and habitats exposed to reducing conditions. However, relatively little is known regarding their diversity and functioning, apart from a few "model species" on which effort has focused over the last 30 yr. In the context of increasing concern about biodiversity and ecosystems, and increasing anthropogenic pressure on oceans, we advocate a better assessment of the diversity of bivalve symbioses in order to evaluate the capacities of these remarkable ecological and evolutionary units to withstand environmental change.

  7. The use of bivalves as rapid, real-time indicators of aquatic pollution

    International Nuclear Information System (INIS)

    The ability of bivalves to filter large volumes of water on a daily basis, combined with the relatively high permeability of their cell membranes, make them valuable organisms to use in the contemporary detection of pollution. Bivalves are well known to respond to chemical contaminants by isolating their soft tissues from the aquatic medium by valve closure. The sensory acuity (via specialized sensory regions including the osphradium) and associated repertoire of this behavioral response can be employed to assess subtle effects exerted by chemical contaminants, such as complex effluents, that may ultimately influence the survival of these organisms. As hazard assessment tools, behavioral studies reflect sublethal toxicity and often yield a highly sensitive estimate of the lowest observable effect concentration (LOEC). Moreover, valve movement behavior has been identified as one of the more sensitive biological early warning measures to a variety of aquatic contaminants, in comparison with those used in other aquatic animal phyla. Therefore, the valve movement behavior of both freshwater (Hyridella depressa, Velesunio angasi and V. ambiguus) and marine (Mytilus edulis) bivalves was continuously monitored, using an on-line computer based data acquisition system, during exposure to either trace metals (e.g. Cu, Cd, Mn and U) or complex effluents (ie treated sewage effluent and acid leachate derived from contaminated Sydney Harbour sediments), in the context of using the valve movement behavior of the bivalve species to indicate the biological significance of exposure to the above-mentioned pollutants. The results indicate that several components of the valve movement behavior of each bivalve provide quantifiable and ecologically interpretable sub-lethal endpoints for the rapid and sensitive evaluation of waters containing either complex effluents or elevated levels of trace metals

  8. First records of Freshwater Bivalves of Ilha Grande National Park, Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Flávio Henrique Ragonha

    2014-03-01

    Full Text Available The Ilha Grande National Park, Paraná, Brazil, is located in the Upper Paraná River and has characteristics typical of a floodplains. This protected area includes lagoons connected and disconnected to the Paraná River, although the latter also connect during periods of high water level, thus composing a heterogeneous group of lacustrine environments. The enormous potential the flora and fauna diversities are still little known to the region, as can be seen through benthic invertebrates, inclunding bivalves mollusks. The granulometric composition of these floodplain lagoons was formed mainly by mud and very fine sand. Furthermore, organic matter composition was predominantly of fine particulate. The other abiotic factors differed from lagoons located within the island of the park to those located in the left margin of Paraná River. The results demonstrated the importance of abiotic factors such as the physical composition of granulometric texture, organic matter and macrophyte banks, to the establishment of bivalves in these floodplain lagoons. We recorded bivalves of Pisidium (native, Diplodon (native, and Corbicula (invasive. The highest values of Diplodon sp. density were observed at São João/C lake, for Pisidium sterkianum (Pilsbry, 1897 at São João/M lake, and to Jatobá/C lagoon with high density of invasive species Corbicula fluminea (Müller, 1774. This study to obtain conduct the first records of freshwater bivalves in floodplains lagoon in the Ilha Grande National Park, and provides contributions to better understanding the ecology of these mollusks. The recording of native species in the region of Upper Paraná River floodplain after a lomg period without new records, demonstrated the importance of protecting the lagoons of the Ilha Grande National Park as they can be a possible refuge to some species of native freshwater bivalves.

  9. FMRFamide-like immunoreactivity in the central nervous system of the cephalopod mollusc, Idiosepius notoides

    DEFF Research Database (Denmark)

    Wollesen, Tim; Loesel, R; Wanninger, Andreas Wilhelm Georg

    2008-01-01

    For more than a century, cephalopod molluscs have been the subject of extensive studies with respect to their complex neuroanatomy and behavior. In comparison to gastropod molluscs surprisingly little work has been carried out on the characterization of neurons in the central nervous system (CNS......) of cephalopods with respect to their neurotransmitter phenotypes. This study presents preliminary results on the distribution of FMRFamide-like immunoreactive neurons within the CNS of the pygmy squid Idiosepius notoides . Its gross neuroanatomy resembles that of other cephalopods. FMRFamide...... the vertical lobes. Although certain immunohistochemical traits are shared with other cephalopods, such as a wall-like arrangement of FMRFamide-like immunoreactive cell somata within the dorsal basal lobe, others have so far only been found in Idiosepius . However, future investigations on other...

  10. Environmental and climatic aspects of the early to mid Holocene calcareous tufa and land mollusc fauna in southern Sweden

    OpenAIRE

    Gedda, Björn

    2001-01-01

    Although deposition of freshwater calcium carbonates, tufa, has occurred in large areas with carbonate soil or bedrock in Sweden, no tufa formation has been observed in Sweden. To better understand the factors controlling tufa formation in southern Sweden, bio- and lithostratigraphical studies were carried out on (paludal) calcareous tufa deposits in the province of Skåne. The biostratigraphical methods include mollusc, pollen, plant macrofossil and insect analysis. These were supplemented by...

  11. Fate of the fragrance material acetyl cedrene in sediment inhabited by the benthic molluscs Macoma balthica and Mya arenaria

    OpenAIRE

    Baral, Kaushal; Burdukovska, Valentina; David, Minodora; Kærhus Olufsen, Mads

    2013-01-01

    In recent time it has come to concern that hydrophobic organic compounds, from the relatively large group of fragrance materials, enter the aquatic environment via drainage systems and bioaccumulate in the sediment and biota. Acetyl cedrene is one of these compounds. In this report the fate and effects of acetyl cedrene were studied on two species of marine molluscs – Macoma balthica and Mya arenaria – with different feeding strategies. An experiment was conducted over a period of 14 days, af...

  12. Characterization of a defensin from the oyster Crassostrea gigas - Recombinant production, folding, solution structure, antimicrobial activities, and gene expression

    OpenAIRE

    Gueguen, Yannick; Herpin, Amaury; Aumelas, André; Garnier, Julien; Fievet, Julie; Escoubas, Jean-Michel; Bulet, Philippe; Gonzalez, Marcelo; Lelong, Christophe; Favrel, Pascal; Bachere, Evelyne

    2006-01-01

    In invertebrates, defensins were found in arthropods and in the mussels. Here, we report for the first time the identification and characterization of a defensin (Cg-Def) from an oyster. Cg-def mRNA was isolated from Crassostrea gigas mantle using an expressed sequence tag approach. To gain insight into potential roles of Cg-Def in oyster immunity, we produced the recombinant peptide in Escherichia coli, characterized its antimicrobial activities, determined its solution structure by NMR spec...

  13. Genetic variability and selective breeding for traits of aquacultural interest in the Pacific oyster (Crassostrea gigas) (slides)

    OpenAIRE

    Boudry, Pierre; Degremont, Lionel; Taris, Nicolas; Mccombie, Helen; Haffray, Pierrick; Ernande, Bruno

    2004-01-01

    To date, the most significant genetic improvement for the production of Pacific oyster (Crassostrea gigas) has been obtained through the breeding of triploids, especially since the development of tetraploids. Quantitative genetics studies suggest that significant gains, for disease resistance or for other traits of aquacultural interest, could be obtained in diploids using this approach. However, the limited extent of hatchery-propagation (versus natural recruitment) and/or various technical ...

  14. Association among growth, food consumption-related traits and amylase gene polymorphism in the Pacific oyster Crassostrea gigas

    OpenAIRE

    Huvet, Arnaud; Jeffroy, F; Fabioux, C; Daniel, Jean-Yves; Quillien, Virgile; Van Wormhoudt, A; Moal, Jeanne; Samain, Jean-francois; Boudry, Pierre; Pouvreau, Stephane

    2008-01-01

    To examine further a previously reported association between amylase gene polymorphism and growth in the Pacific oyster Crassostrea gigas, ecophysiological parameters and biochemical and molecular expression levels of alpha-amylase were studied in Pacific oysters of different amylase genotypes. Genotypes that previously displayed significantly different growth were found to be significantly different for ingestion and absorption efficiency. These estimated parameters, used in a dynamic energy...

  15. Status of the Pacific oyster Crassostrea gigas (Thunberg, 1793) in the western Limfjord, Denmark ‐ Five years of population development

    OpenAIRE

    Groslier, Tilde

    2012-01-01

    The Pacific oyster, Crassostrea gigas, has been present in Europe since it was introduced in 1964 for aquacultural purposes in the Netherlands, from where it has since spread extensively. This study revisits eight locations in the western part of the Limfjord, Denmark, that were examined for the presence of C. gigas in 2006, to determine how the population of Pacific oysters has developed in the five intervening years. Densities where found to have declined at all but two locations on Mors. N...

  16. Gametogenesis in the Pacific Oyster Crassostrea gigas: A Microarrays-Based Analysis Identifies Sex and Stage Specific Genes

    OpenAIRE

    Dheilly, Nolwenn M; Lelong, Christophe; Huvet, Arnaud; Kellner, Kristell; Dubos, Marie-pierre; Riviere, Guillaume; Boudry, Pierre; Favrel, Pascal

    2012-01-01

    Background: The Pacific oyster Crassostrea gigas (Mollusca, Lophotrochozoa) is an alternative and irregular protandrous hermaphrodite: most individuals mature first as males and then change sex several times. Little is known about genetic and phenotypic basis of sex differentiation in oysters, and little more about the molecular pathways regulating reproduction. We have recently developed and validated a microarray containing 31,918 oligomers (Dheilly et al., 2011) representing the oyster tra...

  17. Status of the Pacific Oyster Crassostrea gigas (Thunberg, 1793) in the western Limfjord, Denmark - Five years of population development

    OpenAIRE

    Groslier, Tilde; Christensen, Helle Torp; Davids, Jens; Dolmer, Per; Elmedal, Ingrid; Wejlemann Holm, Mark; Hansen, Benni Winding

    2014-01-01

    The Pacific oyster, Crassostrea gigas, was introduced into the Netherlands in 1964 for aquaculture purposes and has since spread extensively in Northern European waters. Eight locations in the western part of the Limfjord, Denmark, first sampled in 2006 were revisited in 2011, to determine how the population of C. gigas has changed. Densities were lower at all but two locations. No differences in average shell lengths or condition indices were detected. No changes in the number or distributio...

  18. A single bio-energetics growth and reproduction model for the oyster Crassostrea gigas in six Atlantic ecosystems

    OpenAIRE

    ALUNNO-BRUSCIA, Marianne; Bourles, Yves; Maurer, Daniele; Robert, Stephane; Mazurie, Joseph; Gangnery, Aline; Goulletquer, Philippe; Pouvreau, Stephane

    2011-01-01

    Many studies based on bioenergetics growth models have investigated the effects of environmental factors on oyster (Crassostrea gigas) growth and physiology. However, most of these models are site-specific and cannot be applied to other culture sites without the re-estimation of parameters or re-formulation of some processes. We aimed to develop a generic growth model suitable for application in contrasting environments, with a constant set of parameters. We tested the oyster-DEB model (Bourl...

  19. Pacific oyster (Crassostrea gigas) hemocyte are not affected by a mixture of pesticides in short-term in vitro assays

    OpenAIRE

    Moreau, Pierrick; Burgeot, Thierry; Renault, Tristan

    2014-01-01

    Pesticides are frequently detected in estuaries among the pollutants found in estuarine and coastal areas and may have major ecological consequences. They could endanger organism growth, reproduction or survival. In the context of high mortality outbreaks affecting Pacific oysters, Crassostrea gigas, in France since 2008, it appears of importance to determine the putative effects of pesticides on oyster susceptibility to infectious agents. Massive mortality outbreaks reported in this species,...

  20. Application of a dynamic energy budget model to the Pacific oyster, Crassostrea gigas, reared under various environmental conditions

    OpenAIRE

    Pouvreau, Stephane; Bourles, Yves; LEFEBVRE, Sebastien; Gangnery, Aline; ALUNNO-BRUSCIA, Marianne

    2006-01-01

    The Dynamic Energy Budget (DEB) model (Kooijman, S.A.L.M., 1986. Energy budgets can explain body size relations. J. Theor. Biol. 121, 269¿282; Kooijman, S.A.L.M., 2000. Dynamic Energy and Mass Budgets in Biological Systems. Cambridge University Press, Cambridge, 424 pp.) has been adapted to describe the dynamics of growth and reproduction of the Pacific oyster (Crassostrea gigas) reared in different areas under conditions ranging from controlled to natural. The values of the model parameters ...

  1. Gametogenesis, reproductive investment, and spawning behavior of the Pacific giant oyster Crassostrea gigas: evidence of an environment-dependent strategy

    OpenAIRE

    Enriquez-diaz, M.; Pouvreau, Stephane; Chavez-villalba, J.; Le Pennec, M

    2009-01-01

    The progress of gametogenesis was studied in oysters Crassostrea gigas having the same origin (Tremblade), but cultured during 1 year in two distinctive French marine areas, the Baie des Veys and Marennes-Ol,ron. We assessed seasonal changes in the reproduction cycle on the basis of stereological techniques to estimate reproductive investment and measurement of gonad evolution area by quantitative histology. From a qualitative point of view, both oyster groups presented typical reproductive s...

  2. Nutrition and reproduction are key parameters in the interaction process leading to Crassostrea gigas oyster summer mortality in France

    OpenAIRE

    Samain, Jean-francois; Degremont, Lionel; Soletchnik, Patrick; Ropert, Michel; Bedier, Edouard; Mazurie, Joseph; Martin, Jean-Louis; Moal, Jeanne; Mathieu, Michel; Pouvreau, Stephane; Lambert, Christophe; Escoubas, Jean-Michel; Nicolas, Jean-Louis; Le Roux, Frédérique; Renault, Tristan

    2006-01-01

    Complex interactions between oyster, environment and pathogens were observed during the MOREST (2001-2005) project on summer mortality events of Crassostrea gigas oysters in France. The talk will show how nutrition level increasing reproductive intensity generates a risk for pathogen infection under synergistic effect of temperature and stress. Moreover, a genetic component is associated to specific reproductive performances and spawning behaviour. To better understand origin of such resistan...

  3. Sex-Specific Regulation of AMP-Activated Protein Kinase (AMPK) in the Pacific Oyster Crassostrea gigas

    OpenAIRE

    Guevelou, Eric; Huvet, Arnaud; Galindo-sanchez, Clara E.; Milan, Massimo; Quillien, Virgile; Daniel, Jean-yves; Quere, Claudie; Boudry, Pierre; Corporeau, Charlotte

    2013-01-01

    The hermaphrodite Pacific oyster Crassostrea gigas displays a high energy allocation to reproduction. We studied the expression of AMP-activated protein kinase (AMPK) during gametogenesis in the gonad and characterized the mRNA sequences of the AMPK subunits: the AMPK alpha mRNA sequence was previously characterized; we identified AMPK beta, AMPK gamma, and mRNAs of putative AMPK-related targets following bioinformatics mining on existing genomic resources. We analyzed the mRNA expression of ...

  4. Impact of Two Commercial In Vivo Transport Methods on Physiological Condition of the Japanese Oyster (Crassostrea gigas)

    OpenAIRE

    Edgar Iván Jiménez-Ruiz; Enrique Márquez-Ríos; José Luis Cárdenas-López; Nathaly Montoya-Camacho; Francisco Javier Castillo-Yáñez; María Elena Duarte-Figueroa; Saul Ruiz-Cruz; Rosendo Balois-Morales; Víctor Manuel Ocaño-Higuera

    2015-01-01

    The effect of two commercial in vivo transport methods (cardboard boxes and ixtle sacks) on the physiological condition of Japanese oyster (Crassostrea gigas) was evaluated. Total carbohydrates, glycogen, adenosine 5′-triphosphate (ATP) and related products, adenylate energy charge (AEC), and pH of transported oysters in simulated conditions were determined. The results showed that the ATP initial concentration was low from the beginning of the experiment, and AEC decreased in both transport ...

  5. Combined effect of lime (Citrus aurantitolia) and drying on reducing bacteria of public health significance in Edible Oyster (Crassostrea madrasensis)

    OpenAIRE

    Hassan, Femeena; Geethalakshmi, V.; Jeeva, J. Charles; Babu, M. Remya

    2011-01-01

    Combined effect of lime and drying on bacteria of public health significance in Edible Oyster (Crassostrea madrasensis) from Munambam coastal belt (Kerala, India) were studied (without depuration). Samples were examined for Total Plate Count (TPC), Staphylococcus aureus (hygiene indicator), Total coliforms, Faecal coliforms, Escherichia coli, (faecal indicator) Faecal Streptococci (faecal indicator), Salmonella, Vibrio cholera and Listeria monocytogenes. The fresh oyster meat though did not c...

  6. Exposure to the paralytic shellfish toxin producer Alexandrium catenella increases the susceptibility of the oyster Crassostrea gigas to pathogenic vibrios.

    OpenAIRE

    Celina Abi-Khalil; Carmen Lopez-Joven; Eric Abadie; Veronique Savar; Zouher Amzil; Mohamed Laabir; Jean-Luc Rolland

    2016-01-01

    International audience The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France), we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs), was concomitant with the accumulation of PSTs in oyster flesh and the occurrenc...

  7. Impact of Ocean Acidification on Energy Metabolism of Oyster, Crassostrea gigas—Changes in Metabolic Pathways and Thermal Response

    OpenAIRE

    Christian Bock; Sokolova, Inna M.; Silke Eilers; Pörtner, Hans O.; Gisela Lannig

    2010-01-01

    Climate change with increasing temperature and ocean acidification (OA) poses risks for marine ecosystems. According to Pörtner and Farrell [1], synergistic effects of elevated temperature and CO2-induced OA on energy metabolism will narrow the thermal tolerance window of marine ectothermal animals. To test this hypothesis, we investigated the effect of an acute temperature rise on energy metabolism of the oyster, Crassostrea gigas chronically exposed to elevated CO2 levels (partial pressure ...

  8. Influence of one selected Tisochrysis lutea strain rich in lipids on Crassostrea gigas larval development and biochemical composition

    OpenAIRE

    Da Costa, F.; Petton, Bruno; Mingant, Christian; Bougaran, Gael; Rouxel, Catherine; Quere, Claudie; Wikfors, Gary H.; Soudant, Philippe; Robert, Rene

    2016-01-01

    Effects of a remarkably high overall lipid Tisochrysis lutea strain (T+) upon gross biochemical composition, fatty acid (FA), sterol and lipid class composition of Crassostrea gigas larvae were evaluated and compared with a normal strain of Tisochrysis lutea (T) and the diatom Chaetoceros neogracile (Cg). In a first experiment, the influence of different single diets (T, T+ and Cg) and a bispecific diet (TCg) was studied, whereas, effects of monospecific diets (T and T+) and bispecific diets ...

  9. Effects of Hypercapnic Hypoxia on Inactivation and Elimination of Vibrio campbellii in the Eastern Oyster, Crassostrea virginica▿

    OpenAIRE

    Macey, Brett M.; Achilihu, Ikenna O.; Burnett, Karen G.; Burnett, Louis E.

    2008-01-01

    The Eastern oyster, Crassostrea virginica, inhabits shallow coastal waters that frequently experience periods of low dissolved oxygen (hypoxia) and elevated CO2 (hypercapnia) levels. Bacteria are extremely abundant in these environments and accumulate in large numbers in filter-feeding oysters, which can act as passive carriers of human pathogens. Although hypercapnic hypoxia (HH) can affect certain specific immune mechanisms, its direct effect on the inactivation, degradation and elimination...

  10. Shaping mechanisms of metal specificity in a family of metazoan metallothioneins: evolutionary differentiation of mollusc metallothioneins

    Directory of Open Access Journals (Sweden)

    Atrian Sílvia

    2011-01-01

    Full Text Available Abstract Background The degree of metal binding specificity in metalloproteins such as metallothioneins (MTs can be crucial for their functional accuracy. Unlike most other animal species, pulmonate molluscs possess homometallic MT isoforms loaded with Cu+ or Cd2+. They have, so far, been obtained as native metal-MT complexes from snail tissues, where they are involved in the metabolism of the metal ion species bound to the respective isoform. However, it has not as yet been discerned if their specific metal occupation is the result of a rigid control of metal availability, or isoform expression programming in the hosting tissues or of structural differences of the respective peptides determining the coordinative options for the different metal ions. In this study, the Roman snail (Helix pomatia Cu-loaded and Cd-loaded isoforms (HpCuMT and HpCdMT were used as model molecules in order to elucidate the biochemical and evolutionary mechanisms permitting pulmonate MTs to achieve specificity for their cognate metal ion. Results HpCuMT and HpCdMT were recombinantly synthesized in the presence of Cd2+, Zn2+ or Cu2+ and corresponding metal complexes analysed by electrospray mass spectrometry and circular dichroism (CD and ultra violet-visible (UV-Vis spectrophotometry. Both MT isoforms were only able to form unique, homometallic and stable complexes (Cd6-HpCdMT and Cu12-HpCuMT with their cognate metal ions. Yeast complementation assays demonstrated that the two isoforms assumed metal-specific functions, in agreement with their binding preferences, in heterologous eukaryotic environments. In the snail organism, the functional metal specificity of HpCdMT and HpCuMT was contributed by metal-specific transcription programming and cell-specific expression. Sequence elucidation and phylogenetic analysis of MT isoforms from a number of snail species revealed that they possess an unspecific and two metal-specific MT isoforms, whose metal specificity was

  11. Toxic heavy metals in sediments, seawater, and molluscs in the eastern and western coastal waters of Guangdong Province, South China.

    Science.gov (United States)

    Zhang, Ling; Shi, Zhen; Zhang, Jingping; Jiang, Zhijian; Wang, Fei; Huang, Xiaoping

    2016-05-01

    Heavy metal concentrations and distribution were studied in sediments, seawater, and molluscs, and the possible heavy metal sources in the coastal waters of Guangdong Province, South China were discussed. The results showed that the concentrations of Cu, Pb, Zn, and Cr in sediments in eastern coastal waters were generally higher than those in the western coastal waters. However, concentrations of most metals in seawater and molluscs in western waters were higher than in the eastern waters, which was tightly related to the local economics and urbanization development, especially, the different industrial structure in two regions. The main heavy metal sources were attributed to the industrial and agricultural effluent, domestic sewage, and even waste gas. Furthermore, heavy metal contamination assessment indicated that high contamination levels of Cd, Zn, and Pb occurred in sediments in local areas, especially in the bays and harbors. The metal accumulation levels by molluscs ranked following the order of Cd > Cu > As > Zn > Pb > Cr, and the ecological risks introduced by heavy metals in different areas were in the order of Zhanjiang > Yangmao > Shantou > Shanhui. PMID:27126438

  12. Abdominal Angiostrongylosis in Southern Brazil - Prevalence and Parasitic Burden in Mollusc Intermediate Hosts from Eighteen Endemic Foci

    Directory of Open Access Journals (Sweden)

    Rambo Paulo R

    1997-01-01

    Full Text Available Angiostrongylus costaricensis is a parasitic nematode of rodents and molluscs are the intermediate hosts. Nocturnal collection of molluscs and search for infective third stage larvae of A. costaricensis was carried out in 18 endemic foci identified by the notification of a confirmed diagnosis in human biopsies or surgical specimens. Molluscs were digested in acidic solution and isolation of larvae eventually present was done in a Baermann funnel. Larvae identified by the presence of a delicate groove in the tail were counted to assess the individual parasitic burden. Four species were found infected, with ranges of prevalence in parenthesis: Phyllocaulis variegatus (7% to 33.3%; Bradybaena similaris (11.7% to 24.1%; Belocaulus angustipes (8.3% and Phyllocaulis soleiformis (3.3% to 14.2%. Parasitic burden varied from 1 to 75 with P. variegatus, 1 to 98 with B. similaris, 1 to 13 with B. angustipes and 1 larvae in each of two specimens of P. soleiformis. P. variegatus was present in all sites and was found infected with the highest prevalence figures and the highest individual parasitic burdens. These data stress the importance of veronicellid slugs as intermediate hosts for A. costaricensis in the endemic areas in Rio Grande do Sul, Brazil

  13. A shell concentration of the Middle Miocene Crassostrea gryphoides (Schlotheim, 1813) from Siwa Oasis, Western Desert, Egypt

    Science.gov (United States)

    El-Sabbagh, Ahmed M.; El Hedeny, Magdy M.

    2016-08-01

    A concentration of heavy, thick-shelled, large-sized, and elongated population of the oyster Crassostrea gryphoides (Schlotheim, 1813) was recorded in shallow-marine deposits of the basal Oasis Member of the Middle Miocene Marmarica Formation exposed at Siwa Oasis, Egypt. The oyster assemblage is resedimented as a lens-shaped bank up to 80-100 cm thick and about 220 m long. Crassostrea gryphoides specimens are embedded in a yellowish green, soft marl matrix. This is the first documented occurrence of this lens at Siwa Oasis. The lensoid structure is bounded by a lower marl and an upper shale beds of about 2 m and 1.5 m thick, respectively. Assemblage within this lens is characterized by extreme variations of Crassostrea gryphoides, forming an almost monotypic assemblage. The shell packing was dense (shell percentages higher than 75%) at the base and the center of the lens, whereas it exhibits loose packing at the top and right and left sides of the lens (shell percentage less than 15%). Valves are poorly sorted and randomly orientated (both in surface and cross section views). Encrustation and bioerosion have observed on both sides of the left and right valves. The relatively limited varieties of encrusters together with moderate frequency of borings indicate moderate to high sedimentation rate. On the other hand, the low abundance of fragmented and abraded shells indicates good preservation and minimal transport. The studied lens concentration is interpreted as proximal tempestites assemblage.

  14. Nanoscale assembly processes revealed in the nacroprismatic transition zone of Pinna nobilis mollusc shells

    Science.gov (United States)

    Hovden, Robert; Wolf, Stephan E.; Holtz, Megan E.; Marin, Frédéric; Muller, David A.; Estroff, Lara A.

    2015-12-01

    Intricate biomineralization processes in molluscs engineer hierarchical structures with meso-, nano- and atomic architectures that give the final composite material exceptional mechanical strength and optical iridescence on the macroscale. This multiscale biological assembly inspires new synthetic routes to complex materials. Our investigation of the prism-nacre interface reveals nanoscale details governing the onset of nacre formation using high-resolution scanning transmission electron microscopy. A wedge-polishing technique provides unprecedented, large-area specimens required to span the entire interface. Within this region, we find a transition from nanofibrillar aggregation to irregular early-nacre layers, to well-ordered mature nacre suggesting the assembly process is driven by aggregation of nanoparticles (~50-80 nm) within an organic matrix that arrange in fibre-like polycrystalline configurations. The particle number increases successively and, when critical packing is reached, they merge into early-nacre platelets. These results give new insights into nacre formation and particle-accretion mechanisms that may be common to many calcareous biominerals.

  15. Trace metals in seagrass, algae and molluscs from an uncontaminated area in the Mediterranean.

    Science.gov (United States)

    Campanella, L; Conti, M E; Cubadda, F; Sucapane, C

    2001-01-01

    The concentrations of Cd, Cr, Cu, Pb and Zn were measured in specimens of four marine organisms--the seagrass Posidonia oceanica (L.) Delile, the brown algae Padina pavonica (L.) Thivy, and the two gastropod molluscs Monodonta turbinata Born and Patella caerulea L.--selected as possible cosmopolitan biomonitors of trace metals in the Mediterranean area. The organisms were collected at five coastal sites in Favignana Island (Sicily, Italy), an area virtually uninfluenced by anthropogenic activities. In order to gain a more complete picture of both the environmental conditions of the experimental area and the bioaccumulation patterns of the selected organisms, soluble and total metal concentrations were determined in coastal water samples collected at the same stations. The picture of bioavailable metal loads in the different sites of the selected area provided by the four species was rather univocal. An overall trend of increased metal concentrations at the station in which the local harbour is located was clear. On the other hand, the metal concentrations recorded at the 'clean' stations generally fall in the range of the lowest values available in the literature and may be considered as useful background levels to which to refer for intraspecific comparison within the Mediterranean area. Implications in biomonitoring of the observed accumulation patterns, especially in the different tissues of Posidonia oceanica, are discussed. PMID:11202705

  16. Gradual versus punctuated equilibrium evolution in the Turkana Basin molluscs: evolutionary events or biological invasions?

    Science.gov (United States)

    Van Bocxlaer, Bert; Damme, Dirk Van; Feibel, Craig S

    2008-03-01

    A running controversy in evolutionary thought was Eldredge and Gould's punctuated equilibrium model, which proposes long periods of morphological stasis interspersed with rapid bursts of dramatic evolutionary change. One of the earliest and most iconic pieces of research in support of punctuated equilibrium is the work of Williamson on the Plio-Pleistocene molluscs of the Turkana Basin. Williamson claimed to have found firm evidence for three episodes of rapid evolutionary change separated by long periods of stasis in a high-resolution sequence. Most of the discussions following this report centered on the topics of (eco)phenotype versus genotype and the possible presence of preservational and temporal artifacts. The debate proved inconclusive, leaving Williamson's reports as one of the empirical foundations of the paradigm of punctuated equilibrium. Here we conclusively show Williamson's original interpretations to be highly flawed. The supposed rapid bursts of punctuated evolutionary change represent artifacts resulting from the invasion of extrabasinal faunal elements in the Turkana palaeolakes during wet phases well known from elsewhere in Africa. PMID:17999724

  17. Immunohistochemical localization of hepatopancreatic phospholipase in gastropods mollusc, Littorina littorea and Buccinum undatum digestive cells

    Directory of Open Access Journals (Sweden)

    Zarai Zied

    2011-11-01

    Full Text Available Abstract Background Among the digestive enzymes, phospholipase A2 (PLA2 hydrolyzes the essential dietary phospholipids in marine fish and shellfish. However, we know little about the organs that produce PLA2, and the ontogeny of the PLA2-cells. Accordingly, accurate localization of PLA2 in marine snails might afford a better understanding permitting the control of the quality and composition of diets and the mode of digestion of lipid food. Results We have previously producted an antiserum reacting specifically with mSDPLA2. It labeled zymogen granules of the hepatopancreatic acinar cells and the secretory materials of certain epithelial cells in the depths of epithelial crypts in the hepatopancreas of snail. To confirm this localization a laser capture microdissection was performed targeting stained cells of hepatopancreas tissue sections. A Western blot analysis revealed a strong signal at the expected size (30 kDa, probably corresponding to the PLA2. Conclusions The present results support the presence of two hepatopancreatic intracellular and extracellular PLA2 in the prosobranchs gastropods molluscs, Littorina littorea and Buccinum undatum and bring insights on their localizations.

  18. HEAVY METAL POLLUTION OF INDIAN RIVER AND ITS BIOMAGNIFICATIONS IN THE MOLLUSCS

    Directory of Open Access Journals (Sweden)

    Sanindhar Shreedhar Gaikwad

    2014-03-01

    Full Text Available River water is the reliable source of freshwater, which forms the basis of life for variety of creatures. Good water quality of river satisfies the basic need of these organisms. Now day’s due to the continuous water contamination, deterioration of water quality is becomes the serious concern in front of mankind. However, amongst these aquatic contaminants, heavy metals are of major concern. So, present investigation was carried out in order to assess the exact level of heavy metal contaminants and its impact over the aquatic creatures. Panchganga river MS, India was selected for the present study, because of its continuously polluting status. Freshwater mollusc species were selected to assess the biomagnifications due to its easy availability and bio-monitoring properties. Annual investigation concludes the alarming level of heavy metals contamination in the river and its severe deposition or biomagnification in the molluscan body. Contamination affects the total health of the river and hence, there is requirement of advanced scientific skill with practical approach to keep check on them.

  19. Metals in molluscs and algae: A north-south Tyrrhenian Sea baseline

    International Nuclear Information System (INIS)

    We develop a 800 km long relative baseline of metal pollution for the Tyrrhenian Sea, from the north of Naples to south of Sicily (Italy), based on spatio-temporal (1997-2004) concentrations of trace metals in marine organisms and on the bioaccumulative properties of those organisms. The study concerns sites in the gulf of Gaeta-Formia, near Naples, and three islands north, west, and south of Sicily: Ustica, Favignana and Linosa. The five metals are: cadmium, chromium, copper, lead, and zinc; the species include: Monodonta turbinata (n = 161), Patella caerulea (n = 244) and the algae Padina pavonica (n = 84). We use Johnson's (1949) probabilistic method to determine the type of distribution that accounts for our data. It is a system of frequency curves that represents the transformation of the standard normal curves. We find an N-S pollution gradient in molluscs considered: the lowest metal pollution occurs around the Sicilian islands. Our method can accurately characterize marine pollution by contributing to: policy-making, coastal resources management, the assessments of environmental damages from marine accidents and other events. The method here presented is a useful tool for pollution comparisons purposes among ecosystems (i.e., risk monitoring) and it is an ideal starting point for its application on a global scale.

  20. LATE MIDDLE PLEISTOCENE COOL NON-MARINE MOLLUSC AND SMALL MAMMAL FAUNAS FROM LIVORNO (ITALY

    Directory of Open Access Journals (Sweden)

    GIOVANNI ZANCHETTA

    2006-03-01

    Full Text Available New stratigraphic data (exposed sections and boreholes allowed a detailed reconstruction of the northern sector of the "Terrazzo di Livorno" (Central Italy. A new unit, called "Corea formation" was discovered and correlated to marine isotope stage (MIS 6 and to its transition to MIS 5. This formation comprises, at its base, fluvial gravels and sands followed by fine-grained alluvial plain deposits. Non-marine molluscs, small mammals and pollen allow a reconstruction of the environment present during the deposition of the alluvial plain deposits. The environment was mainly an open space, though sparse woodlands should have been present. The non-marine fauna shows features intermediate between typical interglacial and glacial assemblages described so far in Italy. Worth of note is the presence of Orcula dolium and Vallonia enniensis, which now inhabit northern Italy. These findings improve our knowledge on the biogeography of Quaternary non-marine faunas of Central Italy. Stable isotopes data on land snail shells, freshwater shells and pedogenic carbonates showed that climate conditions were cooler than today (possibly 1-2°C less with a significant amount of C4 vegetation, in an environment with moderately dry conditions.

  1. Serotonin immunoreactivity in the central nervous system of the marine molluscs Pleurobranchaea californica and Tritonia diomedea.

    Science.gov (United States)

    Sudlow, L C; Jing, J; Moroz, L L; Gillette, R

    1998-06-15

    The central nervous systems of the marine molluscs Pleurobranchaea californica (Opisthobranchia: Notaspidea) and Tritonia diomedea (Opisthobranchia: Nudibranchia) were examined for serotonin-immunoreactive (5-HT-IR) neurons and processes. Bilaterally paired clusters of 5-HT-IR neuron somata were distributed similarly in ganglia of the two species. In the cerebropleural ganglion complex, these were the metacerebral giant neurons (both species), a dorsal anterior cluster (Pleurobranchaea only), a dorsal medial cluster including identified neurons of the escape swimming network (both species), and a dorsal lateral cluster in the cerebropleural ganglion (Pleurobranchaea only). A ventral anterior cluster (both species) adjoined the metacerebral giant somata at the anterior ganglion edge. Pedal ganglia had the greatest number of 5-HT-IR somata, the majority located near the roots of the pedal commissure in both species. Most 5-HT-IR neurons were on the dorsal surface of the pedal ganglia in Pleurobranchaea and were ventral in Tritonia. Neither the buccal ganglion of both species nor the visceral ganglion of Pleurobranchaea had 5-HT-IR somata. Afew asymmetrical 5-HT-IR somata were found in cerebropleural and pedal ganglia in both species, always on the left side. The clustering of 5-HT-IR neurons, their diverse axon pathways, and the known physiologic properties of their identified members are consistent with a loosely organized arousal system of serotonergic neurons whose components can be generally or differentially active in expression of diverse behaviors. PMID:9619500

  2. Terrestrial molluscs of Pemba Island, Zanzibar, Tanzania, and its status as an “oceanic” island

    Directory of Open Access Journals (Sweden)

    Ben Rowson

    2010-11-01

    Full Text Available Pemba is thought to have had a longer and/or stronger history of isolation than its better-known counterpart, Unguja. The extent to which the biota support this hypothesis of greater oceanicity have been debated. Here, Pemba’s terrestrial mollusc (“land-snail” fauna is surveyed and reviewed for the first time. We find at best equivocal evidence for the following hallmarks of greater oceanicity: impoverishment, imbalance, and a high rate of endemism. At least 49 species are present, families are represented in typical proportions, and there are only between two and four island-endemic species - i.e. a 4% to 8% rate of endemism. For land-snails, isolation thus seems to have been short (Pleistocene or, if longer, weak. Nevertheless, Pemba does host endemic and globally rare species. Forty-five percent of the species found, including most of these, is restricted to forest reserves, with Ngezi Forest Reserve particularly rich. A further 45% are able to tolerate the island’s woody cultivated habitats. One new snail species (Cyclophoridae: Cyathopoma and one new slug species (Urocyclidae: Dendrolimax pro tem. are described. New data and illustrations are provided for other taxa.

  3. Metal-induced stress in bivalves living along a gradient of Cd contamination: relating sub-cellular metal distribution to population-level responses

    International Nuclear Information System (INIS)

    The use of biomarkers to assess the impacts of contaminants on aquatic ecosystems has noticeably increased over the past few years. Few of these studies, however, have contributed to the prediction of ecologically significant effects (i.e., at the population or community levels). The present field study was designed to evaluate the potential of metallothionein (MT) and sub-cellular metal partitioning measurements for predicting toxic effects at higher levels of the biological organization in freshwater bivalves (Pyganodon grandis) chronically exposed to Cd. For that purpose, we quantitatively sampled P. grandis populations in the littoral zone of nine lakes on the Precambrian Canadian Shield during two consecutive summers (1998 and 1999); lakes were characterized by contrasting Cd levels but similar trophic status. We tested relationships between the population status of P. grandis (i.e., growth parameters, density, biomass, secondary production, turnover ratio and cumulative fecundity) and (i) ambient Cd concentrations, (ii) sub-organismal responses (MT concentrations in the gill cytosol of individuals and Cd concentrations in three metal-ligand pools identified as M-HMW, the high molecular weight pool, M-MT, the metallothionein-like pool and M-LMW, the low molecular weight pool) and (iii) ecological confounding factors (food resources, presence of host fishes for the obligatory parasitic larval stage of P. grandis). Our results show that littoral density, live weight, dry viscera biomass, production and cumulative fecundity decreased with increasing concentrations of the free-cadmium ion in the environment (Pearson's r ranging from -0.63 to -0.78). On the other hand, theoretical maximum shell lengths (L∞) in our populations were related to both the dissolved Ca concentration and food quality (sestonic C and N concentrations). Overall, Cd concentrations in the gill cytosolic HMW pool of the individual molluscs were the biomarker response that was most frequently

  4. Polychlorinated biphenyls, organochlorine pesticides and polycyclic aromatic hydrocarbons in a one-off global survey of bivalves

    DEFF Research Database (Denmark)

    Vorkamp, Katrin; Strand, Jakob; Christensen, Jan H.;

    2010-01-01

    During the Danish Galathea 3 expedition, bivalve samples were collected at the Faroe Islands, Greenland, Ghana, South Africa, Australia, Solomon Islands, New Zealand, Chile, US Virgin Islands, Boston, Newfoundland and Shetland Islands and analysed for organochlorines and PAHs. Concentration...

  5. The presence of putative sulphur-oxidizing bacteria colonizing the periostracal secretion in the endosymbiont-bearing bivalve Loripes lucinalis

    OpenAIRE

    Jonhson, M.A.; Fernandez, C

    2001-01-01

    Loripes lucinalis. a small bivalve belonging to the Lucinacea superfamily living in reducing coastal sediments, possesses chemoautotrophic sulphur-oxidizing bacteria in its gill. Here, a population of putative sulphur-oxidizing bacteria is described colonizing the bivalve's inner periostracal secretion. The bacteria, were particularly abundant in the vicinity of the anterior and posterior inhalant syphons. Most of the bacteria observed were oval to rod-shaped and measured 3.9 +/- 1.2 mum on a...

  6. 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.

  7. 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

    2014-01-01

    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. PMID:24473139

  8. Geochemical Fractionation of Copper (Cu, Lead (Pb, and Zinc (Zn in Sediment and their Correlations with Concentrations in Bivalve Mollusc Anadara indica from Coastal Area of Banten Province, Indonesia

    Directory of Open Access Journals (Sweden)

    Noverita Dian Takarina

    2013-06-01

    Full Text Available Surface sediments collected from four sampling stations, each from the coastal area of Tanjung Pasir, Tangerang, and coastal areas of Panimbang, Pandeglang, Banten Province have been geochemically [easily, freely, leachable or exchangeable (EFLE, acid-reducible/Fe-Mn Oxides, oxidisable-organic and resistant] analyzed using AAS Shimadzu 6300 series. Cu, Pb, and Zn content in sediment fraction were correlated with the respective metal concentrations in tissues of Anadara indica collected from the same stations as for those sediment samples. The objective of this study was to determine the concentrations of heavy metals Cu, Pb and Zn in sediments and A. indica as well as to relate the possible differences in the accumulation patterns of Cu, Pb and Zn in A. indica to those in the geochemical fractions in the surface sediment. The results revealed that heavy metal concentrations were recorded to be higher in stations closed to the industries and anthropogenic activities (Garapan rivermouth, Tanjung Pasir compared to agricultural activities (Cibungur rivermouth, Panimbang. Significant (p < 0.01 correlations were observed between Cu in the soft tissue of A. indica with exchangeable, Fe-Mn oxides, oxidisable organic, residual fractions of Cu in the sediment, and Fe-Mn oxides, oxidisable organic, residual fraction for Pb, while significant correlations were observed between Zn in soft tissue of A. indica with Fe-Mn oxides and oxidisable organic fractions. It is suggested that the soft tissue of A. indica could be used as a useful biomonitoring agent for Cu, Pb, and Zn pollution.

  9. Studies on filtration rate in four species of suspension feeding bivalves

    Institute of Scientific and Technical Information of China (English)

    林元烧; 罗文新; 曹文清; 郭东晖; 郑爱榕; 黄长江

    2002-01-01

    The filtration rates of four kinds of bivalves that were cultivated dominantly around Xiamen sea area were measured by using a laboratory flowing system. The experimental results were shown below: (1) Filtration rates were measured in the range of 54~74.8 ml/ (g@min) among the four bivalves, sequencing descently Saccostrea cucullata > Sinonovacula constricta > Mytilus viridis > Ruditapes philippinarum. (2) The relationship between filtration rates on individual size showed a negative exponential function (FR = aWb, FR' = aWb-1), with b - 1 = - 0.435 6 and - 0.392. (3) Filtration rates on Skeletonema costatum were much higher than on Alexandrium tamarensis and Scrippsilla trochoidea inS. Cucullata and R. Philippinarum. (4) FR'on algal densities was also shown a negative function(FR' = aDb-1), with b-1 =-0.143 and-0.215 2 in S.cucullata and R.philippinarum, respectively.

  10. Bio-accumulation kinetics of radioruthenium in marine bivalves-laboratory study

    International Nuclear Information System (INIS)

    Bio-accumulation in marine organisms is a basic and important interaction for the retention and migration of pollutants such as heavy metals and radioactive nuclides in marine environment. Because of their high ability to bioconcentration trace metals and organic compounds, bivalves have been widely applied for monitoring the status of and temporal changes in the trance contaminants, i.e., the Mussel Watch Project of the USA. While their response to chemical change in their surroundings may be detectable within a matter of days, depending on the species and on the contaminants, therefore, bio-accumulation kinetics of pollutants in marine life body is important. In the present paper, three kinds of marine bivalves (wild Saccostrea cucullata, aquacultured Perna viridis and Pinctada martens), collected from Daya Bay, the South China Sea, where the first nuclear power station of China has been running from 1994, were chose to investigate the bio-accumulation of radioruthenium from natural seawater of Daya Bay (pH 8.20, 35 per thousand salinity) under laboratory conditions. Before experiment, the individual bivalve was acclimated for 2 days and then thoroughly washed with seawater to remove surface-adsorbed or/and surface-attached substances which could be an important source of the uptake of particle-reactive radioruthenium. After each interval of experiment, 5 individuals of each kinds of bivalves were sampled, executed, and dissected. The soft tissue was dried, ashed and nitrated and the shell was dried and powdered. The correspondence activity was determined by a γ-ray spectrometer (EG and G ORTEC ADCAM-2000, P-type, relative efficiency 35%). Bio-concentration factor is defined by BCF (mL/g)=103Ru Activity in tissue of bivalves (Bq/g-fresh)/103Ru Activity in seawater (Bq/ml). The plots of BCF of ruthenium in the tissues of bivalves are shown as a function of time The results clearly show that BCF increase sharply with time from beginning to 6 days and approach a

  11. Interactive effects of metal contamination and pathogenic organisms on the marine bivalve Cerastoderma edule

    International Nuclear Information System (INIS)

    The present study evaluated the interactive effects of cadmium contamination and pathogenic organisms (trematodes Himasthla elongata and bacteria Vibrio tapetis) singularly and in combination during 7 days on the bivalve Cerastoderma edule. Some defense-related activities were analyzed such as genetic expression, metallothionein and immune responses. Trematode metacercarial infection, similar whatever the treatment, induced the strongest responses of immune parameters. Particularly, the interaction between cadmium and parasite exposures induced unusual responses on gene expression and immune responses. No effect of bacterial challenge appeared on bivalve responses, nevertheless a strong mortality of V. tapetis infected cockles occured between 7 and 14 days. Cadmium bioaccumulation was significantly modulated by both pathogenic organisms. Furthermore, an antagonistic effect of trematodes and bacteria was shown on metal bioaccumulation of co-infected cockles. These results highlighted the importance of considering the multiplicity of perturbation sources in coastal ecosystems to assess the health status of organisms.

  12. Trace metals in water, sediment and bivalves of a tropical estuary, west coast of India.

    Science.gov (United States)

    Parvez Al-Usmani, S M; Jagtap, T G; Patil, D N

    2015-10-15

    Trace metal pollution was studied in water, sediment and three selected bivalves in Mandovi and Chapora estuaries of Goa. The trace metal in water and sediment of Mandovi was higher than in Chapora. The concentration in the tissues was in the range of 1205.2-2506.7 ppm for Paphia malabarica, 1906.2-2802.6 ppm for Perna viridis and 778.7-1607.5 ppm for Saccostrea cucullata in Mandovi estuary. Tha values for Chapora were 199.4-625.8 ppm for P. malabarica, 812.6-1220.2 for P. viridis and 392.5-418.6 ppm for S. cucullata. The anthropogenic input of metal in Mandovi estuary appears to be mainly responsible for the high accumulation of trace metals. These bivalves have potential to serve as indicator for metal contamination in seafood of Goa. PMID:26228069

  13. Identification of lysozyme activity from two edible bivalves - Perna viridis (Linnaeus) and Meretrix casta (Chemnitz)

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, S.; Tanu; Chatterji, A.

    Pertanika J. Trop. Agric. Sci. 32(1): 85 - 90 (2009) ISSN: 1511-3701 ©Universiti Putra Malaysia Press Received: 20 May 2008 Accepted: 8 October 2008 * Corresponding Author Identification of Lysozyme Activity from Two Edible Bivalves - Perna viridis... the lysozyme from the whole body extracts of two edible and commercially important marine PDF compression, OCR, web optimization using a watermarked evaluation copy of CVISION PDFCompressor 86 Pertanika J. Trop. Agric. Sci. Vol. 32(1) 2009 Sumita Sharma, Tanu...

  14. Some bivalve trace fossils in the Mirosla Plička collection

    Czech Academy of Sciences Publication Activity Database

    Mikuláš, Radek; Uchman, A.

    Prague : Institute of Geology, AS CR, 2006 - (Mikuláš, R.; Rindsberg, A.). s. 25-26 ISBN 80-903511-2-3. [Workshop on Ichnotaxonomy /3./. 04.09.2006- 09.09.2006, Praha, Jevíčko] R&D Projects: GA ČR GA205/05/0917 Institutional research plan: CEZ:AV0Z30130516 Keywords : ichnofossils * bivalves * Protovirgularia * fossil behaviour Subject RIV: EG - Zoology

  15. Paralytic shellfish toxins in bivalves which are not associated with dinoflagellates.

    Science.gov (United States)

    Ogata, T; Sato, S; Kodama, M

    1989-01-01

    Paralytic shellfish toxins (PSP toxins) were detected in the freshwater bivalve Corbicula sandai collected from Lake Biwa, Shiga Prefecture, Japan, and marine mussel Septifer virgatus from Mutsu Bay where known causative dinoflagellates and their cysts have never been observed. The toxin profile of C. sandai and S. virgatus was considerably different from suspected causative organisms Aphanizomenon flos-aquae and Protogonyaulax spp., respectively. The causative organism(s) responsible for PSP toxins in these waters is at present unknown. PMID:2617541

  16. Biogeographic patterns of the marine bivalve Cerastoderma edule along the European coasts

    OpenAIRE

    Krakau, Manuela

    2008-01-01

    The cockle Cerastoderma edule is a common bivalve that inhabits the marine soft-bottom intertidal along European shores. This invertebrate plays a key role in coastal food webs of the Northeast Atlantic coasts due of its high abundances. I studied cockles from 19 sites along the distribution range with the aim to describe the variation of geographic population structures on different analytical levels. Cockles from the Barents Sea to the African Atlantic coast were analysed with respect to th...

  17. Investigation of the molecular ageing process of the long-lived bivalve Arctica islandica

    OpenAIRE

    Gruber, Heike

    2013-01-01

    The question on why we age and how ageing proceeds has occupied researchers’ minds for a long time. Demands on research of healthy ageing and geriatric diseases rise with an older growing human population. Thus, studying the mechanisms of ageing in animals with extraordinarily long lifespans could possibly reveal secrets to longevity and healthy ageing. In this study, a short-lived population of the bivalve mollusk Arctica islandica from the Baltic Sea (with a maximum lifesp...

  18. Paleogene marine bivalves of the deep-water Keasey Formation in Oregon, Part III: The heteroconchs

    OpenAIRE

    Hickman, Carole S.

    2015-01-01

    The heteroconch bivalve fauna of the deep-water (>200 m) Keasey Formation in northwestern Oregon records the Eocene–Oligocene climatic transition and replacement of tropical widely-distributed taxa by the cryophilic taxa that dominate modern high-latitude faunas of the North Pacific. Low-diversity assemblages occur in tuffaceous mudstone and siltstone facies of a deep nearshore basin at the onset of subduction on the Cascadia Margin. Six species of anomalodesmatan heteroconchs have been treat...

  19. An ecosystem-based approach and management framework for the integrated evaluation of bivalve aquaculture impacts

    OpenAIRE

    Cranford, Peter J.; Kamermans, Pauline; Krause, Gesche; Mazurié, Joseph; Buck, Bela H.; Dolmer, Per; Fraser, David; Van Nieuwenhove, Kris; O’Beirn, Francis X.; Sanchez-Mata, Adoración; Thorarinsdóttir, Gudrun G.; Strand, Øivind

    2012-01-01

    An ecosystem-based approach to bivalve aquaculture management is a strategy for the integration of aquaculture within the wider ecosystem, including human aspects, in such a way that it promotes sustainable development, equity, and resilience of ecosystems. Given the linkage between social and ecological systems, marine regulators require an ecosystem-based decision framework that structures and integrates the relationships between these systems and facilitates communication of aquaculture–en...

  20. The categorization and mutual modulation of expanded MyD88s in Crassostrea gigas.

    Science.gov (United States)

    Xin, Lusheng; Wang, Mengqiang; Zhang, Huan; Li, Meijia; Wang, Hao; Wang, Lingling; Song, Linsheng

    2016-07-01

    MyD88 serves as a critical cytosolic adaptor mediating activation of NF-κB in innate immunity. It has been found that there is a considerable expansion of MyD88 in Crassostrea gigas. In the present study, four typical MyD88 genes in Crassostrea gigas (CgMyD88-A to CgMyD88-D) were successfully cloned and their potential functions were investigated together with another two known ones (CgMyD88-T1 and CgMyD88-T2). Multiple alignments revealed that CgMyD88-B and CgMyD88-C remained the conserved DD and TIR domains, while there was a significant variation of E51Q in the DD of CgMyD88-A, and some variations in both DD and TIR domains of CgMyD88-D, respectively. Both truncated CgMyD88-T1 and CgMyD88-T2 lacked Box II in their only TIR domains. Expression pattern analysis showed that CgMyD88-B and CgMyD88-C genes possessed higher expression in normal tissues, compared with the other four. When oysters were under bacteria challenge, CgMyD88-B, CgMyD88-C, CgMyD88-T1 and CgMyD88-T2 were firstly induced, while CgMyD88-A and CgMyD88-D were suppressed. Dual luciferase reporter assays showed that CgMyD88-B and CgMyD88-C could promote the activation of NF-κB signaling pathway, while the other four CgMyD88 genes failed or even suppressed the activities of CgMyD88-B and CgMyD88-C on the activation of NF-κB signaling. It was deduced that after oysters were challenged by bacteria, CgMyD88-B and CgMyD88-C could rapidly and efficiently activate NF-κB signaling pathway to elicit anti-pathogen responses before suppressor CgMyD88 genes (CgMyD88-T1 and CgMyD88-T2) exceeding their expression level. These results suggested that there was mutual modulation of expanded CgMyD88 genes on activating NF-κB signaling pathway in oyster C. gigas. PMID:27074442

  1. Functional-ecological and age-specific regularities of radionuclide concentration by freshwater molluscs of Chernobyl NPP exclusion zone

    International Nuclear Information System (INIS)

    The results of the studies on 90Sr and 137Cs content in the tissues of bivalve and gastropod mollusks of water basins in the exclusion zone of the Chernobyl NPP have been analyzed. The dependence of radionuclide accumulation factors on the peculiarities of morphological structure, functional ecology and nutrition type was found. The age dynamics of 137Cs content in some species of Gastropod was studied

  2. [Mollusc diversity in an Arca zebra (Mollusca: Bivalvia) community, Chacopata, Sucre, Venezuela].

    Science.gov (United States)

    Prieto, A S; Ruiz, L J; García, N; Alvarez, M

    2001-06-01

    The diversity of a subtidal epifaunal mollusk community was studied from September, 1990 to September, 1991 in Chacopata, Sucre State, Venezuela. There were 40 species (24 bivalves and 16 gastropods). The diversity indexes (H' = 2.087, J' = 0.392, 1/D = 0.528) were low when compared with other tropical zones. Monthly diversity reached its maximum in September, 1990 (1.63 bits/ind.) and July, 1991 (1.60 bits/ind.); minimum diversity occurred in June, 1991 (0.52 bits/ind.). A Log series model applied to species abundance data showed a straight line with a diversity index alpha of 5.56. Of 40 species identified, the turkeywing Arca zebra was dominant (69% in number of individuals and 72% of biomass) followed by Pinctada imbricata, Modiolus squamosus, Chama macerophyla and Anadara notabilis. The predatory snails Phyllonotus pomum, Chicoreus brevifrons and Murex recurvirostris seemed to have trophic relationships with A. zebra. The total mean biomass in wet weight (469.20 +/- 263 g m-2, shell included) was high which indicates that A. zebra, a species with a rapid growth rate, occupies a central role in the assemblage as an efficient filter feeder that converts planktonic food into available biomass, supporting one of the most important fisheries in Venezuela. PMID:11935909

  3. The study of the adductor muscle-shell interface structure in three Mollusc species

    Institute of Scientific and Technical Information of China (English)

    ZHU Yaoyao; SUN Chengjun; SONG Yingfei; JIANG Fenghua; YIN Xiaofei; TANG Min; DING Haibing

    2016-01-01

    The adductor muscle scar (AMS) is the fixation point of adductor muscle to the shell. It is an important organic-inorganic interface and stress distribution area. Despite recent advances, our understanding of the structure and composition of the AMS remain limited. Here, we report study on the AMS of three bivalves:Mytilus coruscus, Chlamys farreri andRuditapes philippinarum. Results showed that there were significant differences among their AMS structures. BothM. coruscus andC. farreri were found to have a columnar layer above the nacreous platelet shell structure at the AMS and this layer was more organized inM. coruscus. There was no distinguishable two-layer structure inR. philippinarum. Atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FT-IR) results showed that the AMS was much smoother than the nacreous inner shell in all the three species and the AMS had minor different compositions from the nacreous shell layer. SDS-PAGE (sodium dodecyl-sulfate polyacrylamide gel electophoresis) study of the proteins isolated from the interface indicated that there was a 70 kDa protein which seemed to be specifically located to the highly organized columnar AMS structure inMytilus coruscus. Further analysis of this protein showed it contained high level of Asx (Asp+Asn), Glx (Glu+Gln) and Gly. The special structure and composition of the AMS might play important roles in the stability, adhesion and function at this stress distribution site.

  4. 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.

  5. Triassic bivalves and the initial marine Mesozoic revolution: A role for predators?

    Science.gov (United States)

    McRoberts, Christopher A.

    2001-04-01

    Marine bivalves document the long-term increase in generic richness through the early Mesozoic. Following the end-Permian crisis, the Early Triassic was marked by a gradual recovery in generic richness (57 Induan and 66 Olenekian genera). Diversity slowly increased in the Middle Triassic (98 Anisian and 121 Ladinian genera) and peaked in the Late Triassic (171 Carnian, 165 Norian, and 143 Rhaetian genera). These data support earlier hypotheses that the recovery following the end-Permian extinction was very gradual and was not completed (in terms of both richness and ecologic complexity) until the Ladinian. Although a Carnian-Norian extinction is not evident in the data and may be a regional event limited to the Tethyan realm, the end-Triassic extinction is profound—fewer than 30 genera (reptiles), which had typically low abundances and limited distribution during the Triassic. Drilling predators, although present during the Triassic, are not considered to be prominent causes of mortality among bivalves. Instead, the infaunalization of bivalves during the Triassic may have been due to several interconnected abiotic and biotic causes associated with the recovery after the end-Permian mass extinction.

  6. Environmental changes and shallow marine fossil bivalve assemblages of the Lower Cretaceous Miyako Group, NE Japan

    Science.gov (United States)

    Fujino, Shigehiro; Maeda, Haruyoshi

    2013-03-01

    We reconstructed the environmental changes recorded in the Lower Cretaceous Miyako Group via facies analysis and delineated the relationship between depositional facies and the occurrence of diverse marine invertebrate macrofossils. The Miyako Group consists of deposits from alluvial bay-head delta, bay-head delta front, central bay, and lower shoreface to inner shelf depositional settings. Fossil bivalve assemblages responded to shifts in these sedimentary environments. We defined three fossil bivalve assemblages from the central bay and lower shoreface to inner shelf deposits. The assemblages in the inner shelf and central bay deposits are clearly different, even though they occur within similar depositional facies. This contrast in assemblages results from environmental differences between closed and open settings; this interpretation is supported by the occurrence of stenohaline crinoids. We defined a fourth bivalve assemblage in a tsunami deposit intercalated within the bay-head delta front deposits. It consists of polygenic allochthonous shells, some that were derived from an estuarine environment or the shallow seafloor and others that were torn from small reefs.

  7. Bioaccumulation of cadmium bound to ferric hydroxide and particulate organic matter by the bivalve M. meretrix

    International Nuclear Information System (INIS)

    Ferric hydroxide and particulate organic matter are important pools of trace metals in sediments and control their accumulation by benthic animals. We investigated bioaccumulation of cadmium in bivalve Meretrix meretrix by using a simplified system of laboratory synthesized iron oxides and commercially obtained humic acids to represent the inorganic and organic matrix found in nature. The results showed that bioaccumulation characteristics were distinctly different for these two substrates. Bioaccumulation from ferric hydroxide was not observed at 70 and 140 mg/kg, while the clams started to absorb Cd at 140 mg/kg from organic matter and the bioaccumulation rate was faster than that from ferric hydroxide. Within 28 d, accumulation of Cd from organic matter appeared to reach a steady state after rising to a certain level, while absorption from ferric hydroxide appeared to follow a linear profile. The findings have implications about the assimilation of trace metals from sediments by benthic animals. - Highlights: ► Accumulation of Cd adsorbed on ferric hydroxide and particulate organics was studied. ► Bioaccumulation characteristics were distinctly different for the substrates. ► The result was attributed to different properties and bio-responses of the particles. ► Bivalves may not accumulate more metals associated with more bioavailable particles. - Bioaccumulation characteristics of adsorbed Cd on ferric hydroxide and particulate organic matter by bivalve M. meretrix are distinctly different.

  8. Availability of pearl producing marine bivalves in south-eastern coast of Bangladesh and culture potentialities

    Directory of Open Access Journals (Sweden)

    Md. Ataur Rahman

    2015-12-01

    Full Text Available The present study was conducted during September 2014 to July 2015 to identify the pearl bearing bivalves in south-eastern coast of Bangladesh and culture potentialities of marine oyster in captivity based on field investigation. A total of 7 pearl bearing bivalve species were identified in the coast with a salinity of 18-34 ppt, pH 8.1-8.3 and water depth ranged 0.2-2.0 meter in their habitat. From the collected bivalves, most abundant oyster species windowpane oyster, Placuna placenta (Linnaeus, 1758 was reared in fiber glass tanks with seawater for a period of 6 months. During rearing highest survival rate of 88% was observed in T1 with sandy and gravel substratum and lowest survival rate of 78% was found in T2 with muddy substratum. Average temperature and salinity were varied between 24 °C-25 °C and 21-26 ppt respectively. From the reared oyster, highest 54 nos. small pearls in the month of April and lowest 7 pearls in December from a single P. placenta were obtained. The study proved that pearls can be obtained from the marine oysters in captivity in Bangladesh, and this offers large scale culture potentialities in our coast.

  9. Ethno-malacological knowledge of bivalve mollusks gathering in Acupe mangrove, Santo Amaro, Bahia

    Directory of Open Access Journals (Sweden)

    Francisco José Bezerra Souto

    2009-12-01

    Full Text Available The mangrove is a highly productive ecosystem that carries out important ecological functions and that historically it has been used for the subsistence and income of countless craft fishing communities. In the mangroves of Todos os Santos Bay, including those of the District of Acupe (Santo Amaro – Bahia State, the bivalve mollusks (shellfish are among the most important resources, and their gathering is known as “mariscagem”. This work aims to characterize the knowledge of the local female shellfish gatherers regarding the biology and ecology of bivalve shellfish. Semi-structured interviews were used with local shellfish women (N=54 involving ethnotaxonomy, trophic ecology, hydrodynamics, fenology and ethnocronology. Etic-emic analisys of the data was chosen in order to compare the information obtained in the field to that from the academic literature. The results demonstrated that the shellfish women of Acupe have a significant knowledge of bivalve shellfish, in addition to aspects related to the dynamics of local mangroves, that is sometimes compatible with academic knowledge.

  10. Sodium, K, Ca, Mg, Fe, Cu, and Zn concentrations in molluscs from the Magellan Strait (Chile): their contribution to dietary intake.

    Science.gov (United States)

    España, M S Astorga; Rodríguez, E M Rodríguez; Romero, C Díaz

    2005-08-01

    The concentrations of the essential metals Na, K, Ca, Mg, Fe, Cu, and Zn were determined in 126 specimens of molluscs belonging to five different species: Mytilus chilensis, n=47; Nacella deaurata, n=65; Aulacomya ater, n=4; Fissurella picta, n=4; Acanthina monodon, n=6, collected from the coastline of the Magellan Strait. Significant differences were obtained among the mean metal concentrations in the mollusc species considered. The contribution to the dietary daily intake of these metals for the consumption of one serving of these molluscs was high, especially the contribution to the Fe intake for the consumption of N. deaurata. Some significant differences were observed among the mean concentrations for the studied metals according to the zone of sampling. The influence of the zone of sampling on the mean concentration of metals in N. deaurata was higher than in M. chilensis. The application of lineal discriminant analysis (LDA) made it possible to differentiate statistically between specimens according to the mollusc species. Within the each mollusc species, the LDA helped to identify specimens according to the zone of sampling and weight/length ratio. PMID:16236595

  11. Influence of food on the assimilation of selected metals in tropical bivalves from the New Caledonia lagoon: qualitative and quantitative aspects

    OpenAIRE

    Hédouin, Laëtitia; Metian, Marc; Lacoue-Labarthe, Thomas; Fichez, Renaud; Bustamante, Paco; Warnau, Michel

    2010-01-01

    The present study aimed at examining the influence of food quality and quantity on the assimilation efficiency (AE) of metals in two abundant bivalves in the New Caledonia lagoon, the oyster Isognomon isognomon and the clam Gafrarium tumidum. Bivalves were exposed via their food to the radiotracers of three metals of concern in New Caledonia (54Mn, 57Co and 65Zn) under different feeding conditions (phytoplankton species, cell density, and cell-associated metal concentration). When bivalves we...

  12. Antipyretic, wound healing and antimicrobial activity of processed shell of the marine mollusc Cypraea moneta

    Institute of Scientific and Technical Information of China (English)

    Grasian Immanuel; Berkmans Jude Thaddaeus; Muthusamy Usha; Ramasamy Ramasubburayan; Santhiyagu Prakash; Arunachalam Palavesam

    2012-01-01

    Objective: Some of the products derived from marine organisms have been recommended in alternative system of medicine especially Siddha medicine for several treatments. Among the marine molluscs, Cypraea moneta shell has been used as siddha medicine from ancient days. But no systematic study has been done on its efficacy as antipyretic, wound healing and as antimicrobial agent. In the present study, the protective action of processed shell powder of C. moneta was evaluated by us in an animal model for the above treatments. Methods: C. moneta shell powder was prepared by standard method described in Siddha medicine. Then the antipyretic, wound healing as well as antimicrobial effect of the processed powder was tested in Wister albino rats. Results: By the intravenous injection of yeast cell suspension into albino rats, the antipyretic effect of the shell powder given orally was studied by various concentrations of 0, 10, 20 and 30 mg/ml. The body temperature of the albino rat became normal within a short duration (3h). The wound healing effect of the shell powder was very effective. In the thigh region 2 cm wound was made and the different dosages of shell powder (C -Control, SD - Single dose, DD -Double dosage and TD -Triple dose/day) were applied externally as ointment. The scar was produced in eighth day onwards in DD and TD. Antimicrobial activity was studied in three different oppurtunistic human pathogens such as Micrococcus sp., Proteus vulgaris andSalmonella abory in different concentrations (2, 3, 4 and 5% w/v) of C. moneta shell powder extract. Among these, Proteus vulgaris showed the maximum zone of inhibition (15mm size) against 5% w/v concentration, followed by Micrococcus sp. (12mm) and S. abory (10mm) against the same concentration. Conclusions: The present observation suggested that, processed C. moneta shell powder can be used as an alternative medicine, and it has antipyretic, wound healing as well as antimicrobial properties.

  13. Development of the excretory system in a polyplacophoran mollusc: stages in metanephridial system development

    Directory of Open Access Journals (Sweden)

    Baeumler Natalie

    2012-09-01

    Full Text Available Abstract Background Two types of excretory systems, protonephridia and metanephridial systems are common among bilaterians. The homology of protonephridia of lophotrochozoan taxa has been widely accepted. In contrast, the homology of metanephridial systems – including coelomic cavities as functional units – among taxa as well as the homology between the two excretory systems is a matter of ongoing discussion. This particularly concerns the molluscan kidneys, which are mostly regarded as being derived convergently to the metanephridia of e.g. annelids because of different ontogenetic origin. A reinvestigation of nephrogenesis in polyplacophorans, which carry many primitive traits within molluscs, could shed light on these questions. Results The metanephridial system of Lepidochitona corrugata develops rapidly in the early juvenile phase. It is formed from a coelomic anlage that soon achieves endothelial organization. The pericardium and heart are formed from the central portion of the anlage. The nephridial components are formed by outgrowth from lateral differentiations of the anlage. Simultaneously with formation of the heart, podocytes appear in the atrial wall of the pericardium. In addition, renopericardial ducts, kidneys and efferent nephroducts, all showing downstream ciliation towards the internal lumen, become differentiated (specimen length: 0.62 mm. Further development consists of elongation of the kidney and reinforcement of filtration and reabsorptive structures. Conclusions During development and in fully formed condition the metanephridial system of Lepidochitona corrugata shares many detailed traits (cellular and overall organization with the protonephridia of the same species. Accordingly, we suggest a serial homology of various cell types and between the two excretory systems and the organs as a whole. The formation of the metanephridial system varies significantly within Mollusca, thus the mode of formation cannot be used

  14. Development of the excretory system in a polyplacophoran mollusc: stages in metanephridial system development

    Science.gov (United States)

    2012-01-01

    Background Two types of excretory systems, protonephridia and metanephridial systems are common among bilaterians. The homology of protonephridia of lophotrochozoan taxa has been widely accepted. In contrast, the homology of metanephridial systems – including coelomic cavities as functional units – among taxa as well as the homology between the two excretory systems is a matter of ongoing discussion. This particularly concerns the molluscan kidneys, which are mostly regarded as being derived convergently to the metanephridia of e.g. annelids because of different ontogenetic origin. A reinvestigation of nephrogenesis in polyplacophorans, which carry many primitive traits within molluscs, could shed light on these questions. Results The metanephridial system of Lepidochitona corrugata develops rapidly in the early juvenile phase. It is formed from a coelomic anlage that soon achieves endothelial organization. The pericardium and heart are formed from the central portion of the anlage. The nephridial components are formed by outgrowth from lateral differentiations of the anlage. Simultaneously with formation of the heart, podocytes appear in the atrial wall of the pericardium. In addition, renopericardial ducts, kidneys and efferent nephroducts, all showing downstream ciliation towards the internal lumen, become differentiated (specimen length: 0.62 mm). Further development consists of elongation of the kidney and reinforcement of filtration and reabsorptive structures. Conclusions During development and in fully formed condition the metanephridial system of Lepidochitona corrugata shares many detailed traits (cellular and overall organization) with the protonephridia of the same species. Accordingly, we suggest a serial homology of various cell types and between the two excretory systems and the organs as a whole. The formation of the metanephridial system varies significantly within Mollusca, thus the mode of formation cannot be used as a homology criterion

  15. Circadian rhythms of crawling and swimming in the nudibranch mollusc Melibe leonina.

    Science.gov (United States)

    Newcomb, James M; Kirouac, Lauren E; Naimie, Amanda A; Bixby, Kimberly A; Lee, Colin; Malanga, Stephanie; Raubach, Maureen; Watson, Winsor H

    2014-12-01

    Daily rhythms of activity driven by circadian clocks are expressed by many organisms, including molluscs. We initiated this study, with the nudibranch Melibe leonina, with four goals in mind: (1) determine which behaviors are expressed with a daily rhythm; (2) investigate which of these rhythmic behaviors are controlled by a circadian clock; (3) determine if a circadian clock is associated with the eyes or optic ganglia of Melibe, as it is in several other gastropods; and (4) test the hypothesis that Melibe can use extraocular photoreceptors to synchronize its daily rhythms to natural light-dark cycles. To address these goals, we analyzed the behavior of 55 animals exposed to either artificial or natural light-dark cycles, followed by constant darkness. We also repeated this experiment using 10 animals that had their eyes removed. Individuals did not express daily rhythms of feeding, but they swam and crawled more at night. This pattern of locomotion persisted in constant darkness, indicating the presence of a circadian clock. Eyeless animals also expressed a daily rhythm of locomotion, with more locomotion at night. The fact that eyeless animals synchronized their locomotion to the light-dark cycle suggests that they can detect light using extraocular photoreceptors. However, in constant darkness, these rhythms deteriorated, suggesting that the clock neurons that influence locomotion may be located in, or near, the eyes. Thus, locomotion in Melibe appears to be influenced by both ocular and extraocular photoreceptors, although the former appear to have a greater influence on the expression of circadian rhythms. PMID:25572214

  16. Comparative mapping of GABA-immunoreactive neurons in the central nervous systems of nudibranch molluscs.

    Science.gov (United States)

    Gunaratne, Charuni A; Sakurai, Akira; Katz, Paul S

    2014-03-01

    The relative simplicity of certain invertebrate nervous systems, such as those of gastropod molluscs, allows behaviors to be dissected at the level of small neural circuits composed of individually identifiable neurons. Elucidating the neurotransmitter phenotype of neurons in neural circuits is important for understanding how those neural circuits function. In this study, we examined the distribution of γ-aminobutyric-acid;-immunoreactive (GABA-ir) neurons in four species of sea slugs (Mollusca, Gastropoda, Opisthobranchia, Nudibranchia): Tritonia diomedea, Melibe leonina, Dendronotus iris, and Hermissenda crassicornis. We found consistent patterns of GABA immunoreactivity in the pedal and cerebral-pleural ganglia across species. In particular, there were bilateral clusters in the lateral and medial regions of the dorsal surface of the cerebral ganglia as well as a cluster on the ventral surface of the pedal ganglia. There were also individual GABA-ir neurons that were recognizable across species. The invariant presence of these individual neurons and clusters suggests that they are homologous, although there were interspecies differences in the numbers of neurons in the clusters. The GABAergic system was largely restricted to the central nervous system, with the majority of axons confined to ganglionic connectives and commissures, suggesting a central, integrative role for GABA. GABA was a candidate inhibitory neurotransmitter for neurons in central pattern generator (CPG) circuits underlying swimming behaviors in these species, however none of the known swim CPG neurons were GABA-ir. Although the functions of these GABA-ir neurons are not known, it is clear that their presence has been strongly conserved across nudibranchs. PMID:24638845

  17. Cell-cell interactions determine the dorsoventral axis in embryos of an equally cleaving opisthobranch mollusc.

    Science.gov (United States)

    Boring, L

    1989-11-01

    Dorsoventral polarity in molluscan embryos can arise by two distinct mechanisms, where the mechanism employed is strongly correlated with the cleavage pattern of the early embryo. In species with unequal cleavage, the dorsal lineage, or "D quadrant", is determined in a cell-autonomous manner by the inheritance of cytoplasmic determinants. However, in gastropod molluscs with equal cleavage, cell-cell interactions are required to specify the fate of the dorsal blastomere. During the fifth cleavage interval in equally cleaving embryos, one of the vegetal macromeres makes exclusive contacts with the animal micromeres, and this macromere will give rise to the mesodermal precursor cell at the next division, thereby identifying the dorsal quadrant. This study examines D-quadrant determination in an equally cleaving species from a group of previously uninvestigated gastropods, the subclass Opisthobranchia. Blastomere ablation experiments were performed on embryos of Haminoea callidegenita to (i) determine the developmental potential of macromeres before and after fifth cleavage, and (ii) examine the role of micromere-macromere interactions in the establishment of bilateral symmetry. The results suggest that the macromeres are developmentally equivalent prior to fifth cleavage, but become nonequivalent soon afterward. The dorsoventral axis corresponds to the displacement of the micromeres over one macromere early in the fifth cleavage interval. This unusual cellular topology is hypothesized to result from constraints imposed on micromere-macromere interactions in an embryo that develops from a large egg and forms a stereoblastula (no cleavage cavity). Ablation of the entire first quarter of micromeres results in embryos which remain radially symmetrical in the vegetal hemisphere, indicating that micromere-macromere interactions are required for the elaboration of bilateral symmetry properties. Therefore, inductive interactions between cells may represent a general strategy

  18. Variation in heavy metals concentration in the edible oyster Crassostrea madrasensis, clam Polymesoda erosa and grey mullet Liza aurata from coastline of India

    Digital Repository Service at National Institute of Oceanography (India)

    Gawade, L.; Chari, N.V.H.; Sarma, V.V.; Ingole, B

    . Variation in heavy metals concentration in the edible oyster Crassostrea madrasensis, clam Polymesoda erosa and grey mullet Liza aurata from coastline of India, Indian Journal of Science, 2013, 2(4), 59-63, www.discovery.org.in http://www.discovery.org.in... RESEARCH Gawade Lata et al. Variation in heavy metals concentration in the edible oyster Crassostrea madrasensis, clam Polymesoda erosa and grey mullet Liza aurata from coastline of India, Indian Journal of Science, 2013, 2(4), 59-63, www.discovery.org.in...

  19. Museum Preserved Bivalves as Indicators of Long-term Trends in Methylmercury Concentrations

    Science.gov (United States)

    Luengen, A. C.; Foslund, H. M.; Greenfield, B. K.

    2015-12-01

    Despite the many efforts to reduce mercury concentrations in the environment, there are relatively few datasets on long-term trends in mercury in biota, especially for the bioavailable form, methylmercury (MeHg). This study used museum preserved bivalves (stored in ethanol) to look at MeHg trends in the Asian date mussel Musculista senhousia and the Asian clam Potamocorbula amurensis, collected from San Francisco Bay, California between 1975 and 2012. For each sampling date, 4 to 15 individuals were obtained from museum collections (N = 156 total specimens), freeze-dried, weighed, homogenized, digested, and individually analyzed for MeHg using trace metal clean techniques. The bivalves were also analyzed for δ13C and δ15N to look for changes in food web structure. P. amurensis specimens were only available from 1988 to 2012, and an increase in MeHg was observed during that time. In contrast, M. senhousia specimens were available for the entire 37 year period and exhibited a significant decline in MeHg in the southern reach of the estuary (South Bay). The median MeHg concentration in M. senhousia was highest at 239 ng/g dw in October 1975. That year was the last year of operations for the New Almaden Mercury Mining District, which drained into South Bay. By the 1990s, MeHg concentrations in M. senhousia dropped significantly to a median of 37 ng/g dw. Isotopic δ15N values did not support a hypothesis of reduced trophic position causing the MeHg decline. Over the study duration, δ15N increased in M. senhousia, which we attributed to a baseline shift. We also observed a decline in δ13C since 2000, which may represent a shift in bivalve carbon towards greater utilization of planktonic sources. To validate the use of museum specimens, we ran a preservation study, where we collected fresh bivalves, fixed them in ethanol or formalin, and then transferred them to ethanol for long-term storage. Although MeHg concentrations increased after 1 week, they stabilized over

  20. Uncharted waters: Bivalves of midway atoll and integrating mathematics into biology education

    Science.gov (United States)

    McCully, Kristin M.

    To protect and conserve the Earth's biodiversity and ecosystem services, it is important not only to understand and conserve species and ecosystems, but also to instill an understanding and appreciation for biodiversity and ecosystem services in the next generations of both scientists and citizens. Thus, this dissertation combines research into the ecology and identity of large bivalves at Midway Atoll in the Northwestern Hawaiian Islands (NWHI) with research on pedagogical strategies for integrating mathematics into undergraduate biology education. The NWHI is one of the few remaining large, mainly intact, predator-dominated coral reef ecosystems and one of the world's largest marine protected areas. Previous bivalve studies focused on the black-lipped pearl oyster, Pinctada margaritifera, which was heavily harvested in the late 1920s, has not recovered, and is now a candidate species for restoration. First, I combined remote sensing, geographic information systems, SCUBA, and mathematical modeling to quantify the abundance, spatial distributions, and filtration capacity of large epifaunal bivalves at Midway Atoll. These bivalves are most abundant on the forereef outside the atoll, but densities are much lower than reported on other reefs, and Midway's bivalves are unlikely to affect plankton abundance and productivity inside the lagoon. Second, I used molecular techniques and phylogenetic reconstructions to identify pearl oysters (Pinctada) from Midway Atoll as P. maculata , a species not previously reported in Hawaii. As a small morphologically cryptic species, P. maculata may be a native species that has not been collected previously, a native species that has been identified incorrectly as the morphologically similar P. radiata, or it may be a recent introduction or natural range extension from the western Pacific. Finally, I review science education literature integrating mathematics into undergraduate biology curricula, and then present and evaluate a

  1. Radiosensitivity of Salmonella spp and Vibrio parahaemolyticus artificially incorporated by oysters (Crassostrea brasiliana)

    International Nuclear Information System (INIS)

    Irradiation is considered one of the most efficient technological process to reduce the number of microorganisms in food. It can be used to improve the safety of food products as well as their shelf life. Oysters are considered one of the most important vehicle of pathogenic bacteria due to their feeding characteristic and because they are usually ingested raw. The aim of this study was to evaluate the influence of gamma radiation process on high levels of Salmonella Enteritidis, Salmonella Infantis and Vibrio parahaemolyticus incorporated by oysters (Crassostrea brasiliana) as well as on the survival of the animals and sensory attributes. The oysters were submitted to gamma radiation treatment (60Co) with doses ranging from 0.5 kGy to 3.0 kGy. At least four trials were conducted for each serotype. The dose of 3.0 kGy was, generally, sufficient to reduce the level of Salmonella serotypes in 6 log while for V.parahaemolyticus the dose as 1.o kGy. Animals were not killed and sensory attributes were not changed by the highest irradiation dose. Therefore, 3.0 kGy is a dose that is effective on the inactivation of Salmonella spp and V.parahaemolyticus in oysters without changing their odour, flavour and appearance. (author)

  2. Role of dissolved and particulate cadmium in the accumulation of cadmium in cultured oysters (Crassostrea gigas)

    International Nuclear Information System (INIS)

    Pacific oysters (Crassostrea gigas) collected on the coast of British Columbia, Canada have occasionally shown cadmium (Cd) concentrations at or above 2 μg g-1 (wet weight), which has resulted in the loss of some international markets. This study investigated the source and transfer of Cd to oysters by focusing on the role of dissolved and particulate Cd in seawater. Parameters monitored for 1 year at two oyster farm sites on Vancouver Island included: oyster tissue mass and shell length, Cd in oysters, dissolved Cd, particulate Cd, temperature and salinity. Results show that dissolved Cd was the main source of Cd to the oysters and that Cd was mainly concentrated in the gut tissues. A seasonal trend was observed in Cd in oysters, in which levels were lowest during periods of higher temperatures. Results also indicate that the local oceanographic inputs and sediment diagenesis directly affect dissolved Cd and thereby influence the Cd levels in oysters. Particulate matter was not found to be a source of Cd in oysters, and was actually negatively correlated. This was likely due to the uptake of dissolved Cd by phytoplankton and the effect of phytoplankton on oyster tissue mass

  3. Suppression of chemiluminescence of eastern oyster (Crassostrea virginica) hemocytes by the protozoan parasite Perkinsus marinus.

    Science.gov (United States)

    Volety, A K; Chu, F L

    1995-01-01

    Experiments were conducted to determine the ability of the protistan parasite, Perkinsus marinus, to inhibit chemiluminescence of hemocytes from the eastern oyster, Crassostrea virginica. Luminol-enhanced chemiluminescence (CL) was used to measure the production of reactive oxygen intermediates (ROI) generated by oyster hemocytes using zymosan as a stimulant. To determine whether P. marinus suppresses ROI evoked from zymosan-stimulated hemocytes, live or heat killed P. marinus in filtered estuarine water (YRW) (salinity = 20 ppt) were added to (1) zymosan-stimulated hemocytes after CL reached its peak, or (2) hemocytes at the same time as zymosan, and reduction of CL responses were recorded. In both tests, controls received only estuarine water. Live P. marinus meronts significantly suppressed ROI production by zymosan-stimulated hemocytes. The suppression of ROI production was dose dependent. Suppression of ROI production from zymosan-stimulated hemocytes by heat killed P. marinus was significantly less than by live P. marinus. Similarly, CL of hemocytes was reduced, though not significantly when hemocytes were exposed to YRW preincubated with P. marinus. When P. marinus meronts were used as a stimulant, no CL response was elicited. Results of this study suggest that P. marinus cells are able to suppress ROI release from oyster hemocytes, thus evading this component of the host's defense. PMID:7556800

  4. Environmental factors responsible for the incidence of antibiotic resistance genes in pristine Crassostrea virginica reefs

    International Nuclear Information System (INIS)

    Highlights: ► Estuary was the major source of antibiotic resistance genes (ARG) for tidal creeks. ► Watersheds were the secondary source of ARG for tidal creeks. ► Watershed contribution corresponded to the degree of its anthropogenic disturbance. ► ARG in tidal creeks were carried by native hosts preferring low termohaline niches. ► ARG incidence was the highest in oysters implying ARG bioaccumulation/proliferation. - Abstract: The occurrence of tetracycline resistance (TRG) and integrase (INT) genes were monitored in Crassostrea virginica oyster reefs of three pristine creeks (SINERR, Georgia, USA). Their profiles revealed 85% similarity with the TRG/INT profiles observed in the adjacent to the SINERR and contaminated Altamaha River estuary (Barkovskii et al., 2010). The TRG/INT spectra and incidence frequencies corresponded to the source of oceanic input and to run-offs from creeks’ watersheds. The highest incidence frequencies and concentrations were observed in oysters. TRG/INT incidences correlated positively (Spearman Rank = 0.88), and negatively correlated (−0.63 to −0.79) with creek salinity, conductivity, dissolved solids, and temperature. Coliform incidence positively correlated with temperature, and not with the TRG/INT incidence. The Altamaha River estuary was the primary TRG/INT source for the reefs with contributions from creek’s watersheds. TRG/INT were carried by non-coliforms with a preference for low-to-temperate thermohaline environments coupled with bioaccumulation by oysters.

  5. Differential fertilization success between two populations of eastern oyster, Crassostrea virginica.

    Science.gov (United States)

    Zhang, Haibin; Scarpa, John; Hare, Matthew P

    2010-10-01

    Identification of mechanisms promoting prezygotic reproductive isolation and their prevalence are key goals in evolutionary biology because of their potential role in speciation. In marine broadcast-spawning species, molecular interactions between gamete surface proteins are more important than mating behavior for determining reproductive compatibility. Evidence for differential fertilization capacity has been reported from experiments utilizing competing sperm from two males sampled within populations and between species, but to our knowledge conspecific populations that might have diverged in allopatry have never been tested on the basis of sperm competition. In the present study, the gametic compatibility and embryo survivorship from matings between two allopatric populations of Crassostrea virginica, the eastern oyster, on either side of a genetic step cline were investigated. Fertilization success, embryo survival, and paternity data all indicated an absence of strong reproductive barriers between the two oyster populations, implicating other mechanisms for maintenance of the cline step. Sperm from northern male oysters showed a tendency to produce more larvae than expected when competing with sperm from southern male oysters. Although the northern male advantage was not strong, the trend implies that long-distance dispersal across the step cline might more successfully result in north-to-south gene flow than the reverse, providing a mechanistic hypothesis explaining the asymmetric cline shape. PMID:20972259

  6. Growth and reproductive investment of introduced Pacific oysters Crassostrea gigas in southern European waters

    Science.gov (United States)

    Cardoso, Joana F. M. F.; Peralta, Nelson R. E.; Machado, Jorge P.; van der Veer, Henk W.

    2013-02-01

    Growth and reproductive investment of cultured Pacific oysters Crassostrea gigas were studied in two south-western European estuaries: the Ría de Ribadeo in Spain and the Ria Formosa in Portugal. Developing gonads were found in individuals >23.5 mm shell length in the Ria Formosa and >27.5 mm shell length in the Ría de Ribadeo. Although the amount of gonadal mass in relation to total body mass was higher in the Ría de Ribadeo, oysters from this location did not spawn completely. In contrast, oysters from the Ria Formosa completely emptied their gonad during spawning. Reproduction and, consequently, the maximum potential for population expansion may be constrained in both areas: in the Ría de Ribadeo due to suboptimal spawning threshold temperatures and in the Ria Formosa due to higher metabolic costs caused by warmer winter temperatures. Nevertheless, in comparison to northern oyster populations, Portuguese and Spanish populations have higher reproductive output. If suitable environmental conditions are met, expansion of Portuguese and Spanish populations will most likely occur. In the Ria Formosa, where environmental conditions for growth and reproduction are favourable, wild oysters are already observed. In order to follow the dynamics of oyster populations and predict possible negative effects on the ecosystems, it is important to continue monitoring the physiological performance of C. gigas in these areas.

  7. Reproductive responses and detoxification of estuarine oyster Crassostrea hongkongensis under metal stress: a seasonal study.

    Science.gov (United States)

    Weng, Nanyan; Wang, Wen-Xiong

    2015-03-01

    Understanding the impacts of metal stress on the reproduction of dominant species, such as oysters, in seriously contaminated estuarine environments has great ecological implications. In the present study, the reproductive conditions were examined monthly for 1 year in oysters Crassostrea hongkongensis from a heavily metal-contaminated site (Baijiao, mainly by Cu and Zn) in the Jiulong River estuary and a relatively clean nearby estuary (Jiuzhen). Oysters sampled in the contaminated site showed a delayed gametogenesis, a relatively shorter spawning period, and a lower gonad condition index in comparison to the oysters sampled in the reference site. In particular, we found that the proportion of females increased significantly in the contaminated oysters, which provided the first evidence that the feminization in wild oyster populations could be related to trace metal pollution. Additionally, the potential detoxification mechanism of trace metals in oysters was also investigated. Compartmentalization of trace metals in membrane-limited vesicles in hemocytes could be an important detoxification mechanism for the contaminated oysters. Our findings indicated that the long-term metal exposure may greatly influence the reproduction of the oysters and finally affect the recruitment and population of this species. PMID:25660751

  8. Distinct immune responses of juvenile and adult oysters (Crassostrea gigas) to viral and bacterial infections.

    Science.gov (United States)

    Green, Timothy J; Vergnes, Agnes; Montagnani, Caroline; de Lorgeril, Julien

    2016-01-01

    Since 2008, massive mortality events of Pacific oysters (Crassostrea gigas) have been reported worldwide and these disease events are often associated with Ostreid herpesvirus type 1 (OsHV-1). Epidemiological field studies have also reported oyster age and other pathogens of the Vibrio genus are contributing factors to this syndrome. We undertook a controlled laboratory experiment to simultaneously investigate survival and immunological response of juvenile and adult C. gigas at different time-points post-infection with OsHV-1, Vibrio tasmaniensis LGP32 and V. aestuarianus. Our data corroborates epidemiological studies that juveniles are more susceptible to OsHV-1, whereas adults are more susceptible to Vibrio. We measured the expression of 102 immune-genes by high-throughput RT-qPCR, which revealed oysters have different transcriptional responses to OsHV-1 and Vibrio. The transcriptional response in the early stages of OsHV-1 infection involved genes related to apoptosis and the interferon-pathway. Transcriptional response to Vibrio infection involved antimicrobial peptides, heat shock proteins and galectins. Interestingly, oysters in the later stages of OsHV-1 infection had a transcriptional response that resembled an antibacterial response, which is suggestive of the oyster's microbiome causing secondary infections (dysbiosis-driven pathology). This study provides molecular evidence that oysters can mount distinct immune response to viral and bacterial pathogens and these responses differ depending on the age of the host. PMID:27439510

  9. Phylogeny of forkhead genes in three spiralians and their expression in Pacific oyster Crassostrea gigas

    Science.gov (United States)

    Yang, Mei; Xu, Fei; Liu, Jun; Que, Huayong; Li, Li; Zhang, Guofan

    2014-11-01

    The Fox genes encode a group of transcription factors that contain a forkhead domain, which forms a structure known as a winged helix. These transcription factors play a crucial role in several key biological processes, including development. High-degree identity in the canonical forkhead domain has been used to divide Fox proteins into 23 families (FoxA to FoxS). We surveyed the genome of three spiralians, the oyster Crassostrea gigas, the limpet Lottia gigantea, and the annelid Capitella teleta. We identified 25 C. gigas fox genes, 21 L. gigantea fox genes, and 25 C. teleta fox genes. The C. gigas fox and L. gigantea fox genes represented 19 of the 23 families, whereas FoxI, Q1, R, and S were missing. The majority of the Fox families were observed within the C. teleta fox genes, with the exception of FoxR and S. In addition, the foxAB-like gene, foxY-like gene, and foxH gene were also present in the three genomes. The conserved FoxC-FoxL1 cluster, observed in mammals, was also found in C. gigas. The diversity of temporal expression patterns observed across the developmental process implies the C. gigas fox genes exert a wide range of functions. Further functional studies are required to gain insight into the evolution of Fox genes in bilaterians.

  10. Growth of Crassostrea gasar cultured in marine and estuary environments in Brazilian waters

    Directory of Open Access Journals (Sweden)

    Gustavo Ruschel Lopes

    2013-08-01

    Full Text Available The objective of this work was to evaluate the growth of the mangrove oyster Crassostrea gasar cultured in marine and estuarine environments. Oysters were cultured for 11 months in a longline system in two study sites - São Francisco do Sul and Florianópolis -, in the state of Santa Catarina, Southern Brazil. Water chlorophyll-α concentration, temperature, and salinity were measured weekly. The oysters were measured monthly (shell size and weight gain to assess growth. At the end of the culture period, the average wet flesh weight, dry flesh weight, and shell weight were determined, as well as the distribution of oysters per size class. Six nonlinear models (logistic, exponential, Gompertz, Brody, Richards, and Von Bertalanffy were adjusted to the oyster growth data set. Final mean shell sizes were higher in São Francisco do Sul than in Florianópolis. In addition, oysters cultured in São Francisco do Sul were more uniformly distributed in the four size classes than those cultured in Florianópolis. The highest average values of wet flesh weight and shell weight were observed in São Francisco do Sul, whereas dry flesh weight did not differ between the sites. The estuary environment is more promising for the cultivation of oysters.

  11. The simple neuroendocrine-immune regulatory network in oyster Crassostrea gigas mediates complex functions

    Science.gov (United States)

    Liu, Zhaoqun; Wang, Lingling; Zhou, Zhi; Sun, Ying; Wang, Mengqiang; Wang, Hao; Hou, Zhanhui; Gao, Dahai; Gao, Qiang; Song, Linsheng

    2016-05-01

    The neuroendocrine-immune (NEI) regulatory network is a complex system, which plays an indispensable role in the immunity of the host. In the present study, the bioinformatical analysis of the transcriptomic data from oyster Crassostrea gigas and further biological validation revealed that oyster TNF (CgTNF-1 CGI_10018786) could activate the transcription factors NF-κB and HSF (heat shock transcription factor) through MAPK signaling pathway, and then regulate apoptosis, redox reaction, neuro-regulation and protein folding in oyster haemocytes. The activated immune cells then released neurotransmitters including acetylcholine, norepinephrine and [Met5]-enkephalin to regulate the immune response by arising the expression of three TNF (CGI_10005109, CGI_10005110 and CGI_10006440) and translocating two NF-κB (Cgp65, CGI_10018142 and CgRel, CGI_10021567) between the cytoplasm and nuclei of haemocytes. Neurotransmitters exhibited the immunomodulation effects by influencing apoptosis and phagocytosis of oyster haemocytes. Acetylcholine and norepinephrine could down-regulate the immune response, while [Met5]-enkephalin up-regulate the immune response. These results suggested that the simple neuroendocrine-immune regulatory network in oyster might be activated by oyster TNF and then regulate the immune response by virtue of neurotransmitters, cytokines and transcription factors.

  12. Acetylcholinesterase inhibition and micronucleus frequency in oysters (Crassostrea corteziensis exposed to chlorpyrifos

    Directory of Open Access Journals (Sweden)

    AB Benitez-Trinidad1

    2014-09-01

    Full Text Available Chlorpyrifos (CPF is an Organophosphorous pesticide (OP that has been widely used for both agricultural and domestic pest control. To date, there is little information regarding the effects of this pesticide on aquatic organisms, particularly oysters. The aim of this study was to evaluate Acetylcholinesterase (AChE activity and Micronucleus (MN frequency in the oyster Crassostrea corteziensis in laboratory exposure with CPF (20, 40, 60, 80, and 160 μg/L and in a field study. The results showed that AChE was reduced 60 - 82 % in oysters exposed to CPF, relative to the negative control. Similar AChE results were observed in oysters collected from the Boca de Camichín Estuary in Nayarit, Mexico; with respect to genetic damage, evaluated through MN, treatment with CPF did not induce the MN frequency, nor did the oyster from the field study exhibit an increase in this biomarker. These results suggest that C. corteziensis is a sensitive model for evaluating the acute toxicity of OP in laboratory studies as well in the field. In addition, it generates prospects on studying mechanisms through which the oyster could possess resistance to genotoxic agents, as well as its being a reliable model for evaluating the genotoxic effects of xenobiotics through the MN technique.

  13. Linkage disequilibrium in wild and cultured populations of Pacific oyster ( Crassostrea gigas)

    Science.gov (United States)

    Guo, Xiang; Li, Qi; Kong, Lingfeng; Yu, Hong

    2016-04-01

    Linkage disequilibrium (LD) can be applied for mapping the actual genes responsible for variation of economically important traits through association mapping. The feasibility and efficacy of association studies are strongly dependent on the extent of LD which determines the number and density of markers in the studied population, as well as the experimental design for an association analysis. In this study, we first characterized the extent of LD in a wild population and a cultured mass-selected line of Pacific oyster ( Crassostrea gigas). A total of 88 wild and 96 cultured individuals were selected to assess the level of genome-wide LD with 53 microsatellites, respectively. For syntenic marker pairs, no significant association was observed in the wild population; however, three significant associations occurred in the cultured population, and the significant LD extended up to 12.7 cM, indicating that strong artificial selection is a key force for substantial increase of genome-wide LD in cultured population. The difference of LD between wild and cultured populations showed that association studies in Pacific oyster can be achieved with reasonable marker densities at a relatively low cost by choosing an association mapping population. Furthermore, the frequent occurrence of LD between non-syntenic loci and rare alleles encourages the joint application of linkage analysis and LD mapping when mapping genes in oyster. The information on the linkage disequilibrium in the cultured population is useful for future association mapping in oyster.

  14. High mobility group protein DSP1 negatively regulates HSP70 transcription in Crassostrea hongkongensis.

    Science.gov (United States)

    Miao, Zongyu; Xu, Delin; Cui, Miao; Zhang, Qizhong

    2016-06-10

    HSP70 acts mostly as a molecular chaperone and plays important roles in facilitating the folding of nascent peptides as well as the refolding or degradation of the denatured proteins. Under stressed conditions, the expression level of HSP70 is upregulated significantly and rapidly, as is known to be achieved by various regulatory factors controlling the transcriptional level. In this study, a high mobility group protein DSP1 was identified by DNA-affinity purification from the nuclear extracts of Crassostrea hongkongensis using the ChHSP70 promoter as a bait. The specific interaction between the prokaryotically expressed ChDSP1 and the FITC-labeled ChHSP70 promoter was confirmed by EMSA analysis. ChDSP1 was shown to negatively regulate ChHSP70 promoter expression by Luciferase Reporter Assay in the heterologous HEK293T cells. Both ChHSP70 and ChDSP1 transcriptions were induced by either thermal or CdCl2 stress, while the accumulated expression peaks of ChDSP1 were always slightly delayed when compared with that of ChHSP70. This indicates that ChDSP1 is involved, very likely to exert its suppressive role, in the recovery of the ChHSP70 expression from the induced level to its original state. This study is the first to report negative regulator of HSP70 gene transcription, and provides novel insights into the mechanisms controlling heat shock protein expression. PMID:27154224

  15. Effects of cadmium on aneuploidy and hemocyte parameters in the Pacific oyster, Crassostrea gigas

    International Nuclear Information System (INIS)

    Pacific oysters, Crassostrea gigas, are commonly reared in estuaries where they are exposed to anthropogenic pollution. Much research has been made on the toxicity of cadmium to aquatic organisms because the compound recurrently contaminates their environment. Our study examined the influence of cadmium on aneuploidy level (lowered chromosome number in a percentage of somatic cells) and hemocyte parameters in C. gigas at different stages of life. Adults and juveniles were exposed to two different concentrations of cadmium. The first concentration applied was equivalent to a peak value found in Marennes-Oleron bay (Charente-Maritime, France; 50 ng L-1) and the second was 10 times higher (500 ng L-1). Exposure to 50 ng L-1 cadmium caused a significant decrease in the survival time of C. gigas, but exposure to 500 ng L-1 surprisingly affected the survival time positively. Significant differences in aneuploidy level were observed between the cadmium treatments and the control in adults but not in juveniles or the offspring of the adult groups. The effects of cadmium on hemocyte parameters were analyzed by flow cytometry. Several hemocyte parameters increased significantly after 21 days of cadmium exposure and subsequently decreased. Phenoloxidase-like activity, evaluated by spectrophotometry, varied over the time of the experiment and increased after 66 days of contact with 500 ng L-1 cadmium. Taken together, cadmium at environmentally relevant concentrations seems to have only moderate effects on aneuploidy and hemocyte parameters

  16. Stress tolerance of a subtropical Crassostrea virginica population to the combined effects of temperature and salinity

    Energy Technology Data Exchange (ETDEWEB)

    Heilmayer, Olaf; DiGialleonardo, Julian J.; Qian, Lianfen; Roesijadi, Guritno

    2008-08-10

    The combination of salinity and temperature has synergistic effects on virtually all aspects of the biology of estuarine organisms. Of interest were site-specific characteristics in the response of the eastern oyster, Crassostrea virginica, from the St. Lucie River Estuary to the interactive effects of temperature and salinity. This estuary, one of the largest on the central east coast of Florida, is strongly influenced by anthropogenic modifications due to management needs to control the patterns of freshwater flow in the St. Lucie River watershed. C. virginica is designated a valued ecosystem component for monitoring the health of this estuary. Our approach used a multidimensional response surface design to study the effects of temperature and salinity on sublethal measures of oyster performance: (1) body condition index as an overall indicator of bioenergetic status and (2) the RNA/DNA ratio as a biochemical indicator of cellular stress. The results showed that there was a greater ability to withstand extreme salinity conditions at lower temperatures. However, there were no site-specific attributes that differentiated the response of the St. Lucie Estuary population from populations along the distribution range. Condition index was a less variable response than the RNA/DNA ratio, and the final models for mean condition index and the RNA:DNA ratios explained 77.3% and 35.8% of the respective variances.

  17. Response to Selection for Fast Growth in the Second Generation of Pacific Oyster (Crassostrea gigas)

    Institute of Scientific and Technical Information of China (English)

    WANG Qingzhi; LI Qi; KONG Lingfeng; YU Ruihai

    2012-01-01

    Mass selection for fast growth was conducted in three Pacific oyster(Crassostrea gigas)stocks from China,Japan and Korea using previously established lines(CS1,JS 1,and KS 1).To determine whether continuous progress can be achieved by selection for growth,the progeny of three second-generation Pacific oyster lines was selected for shell height and evaluated via a 400-day farming experiment.When harvested at the end of the experiment,the selected crosses of CS2,JS2,and KS2 lines grew by 9.2%,10.2% and 9.6% larger than the control crosses,respectively.During grow-out stage,the genetic gain of three selected lines was (10.2 ± 1.4)%,(10.4 ± 0.3)%,and(8.4 ± 1.6)%,respectively;and the corresponding realized heritability was 0.457 ± 0.143,0.312 ±0.071 and 0.332 ± 0.009,respectively.These results indicated that the selection for fast growth achieved steady progress in the second generation of oyster.Our work provides supportive evidence for the continuity of the Pacific oyster selective breeding program.

  18. Desarrollo de la Ostricultura de Crassostrea corteziensis en Panamá. Identificación y cuantificación de organismos colonizadores de la ostra Crassostrea corteziensis cultivada en fincas camaroneras

    OpenAIRE

    Sainz-Méndez, Ingrid; Vergara-López, Pablo

    2005-01-01

    La ostra Crassostrea corteziensis (Hertlein, 1951) comúnmente conocida como “ostión u ostra del placer” es un molusco bivalvo nativo, que habita la zona intermareal de áreas de baja influencia estuarina. Se encuentra distribuida geográficamente desde el Golfo de California hasta Perú (Fisher et al.,1995). La creciente industria de la acuicultura de bivalvos, ha registrado en algunas localidades del continente americano la infestación de sus cultivos por parte de algunas especies que, en v...

  19. Artificial radioactivity in edible parts of giant clam mollusc from Mururoa atoll from 1967 to 1990. Health physics aspect

    International Nuclear Information System (INIS)

    Radionuclides concentration by giant clams is associated with feeding habit. It's also a main food for polynesian atolls inhabitants, elsewhere than Mururoa island because this mollusc is not consumed like all the other fishery products from this atoll lagoon. Nevertheless measurements of ten artificial radionuclides are performed in edible parts of giant clams fished from Mururoa lagoon since the beginning of nuclear tests. The decay of radionuclides concentration is described versus time. To go further on we have computed the dose-equivalent for internal exposure of an eventual giant clams eater. It is estimated that the resulting risk of malignancy is below than 1 per 10 000

  20. Development of a comet-FISH assay for the detection of DNA damage in hemocytes of Crassostrea gigas

    OpenAIRE

    Perez Garcia, Maria Concepcion; Rouxel, Julien; Akcha, Farida

    2015-01-01

    In this work, the DNA-damaging effect of hydrogen peroxide on the structural integrity of nucleolar organizer regions (NORs) was studied for the first time by comet-FISH in the Pacific oyster Crassostrea gigas. Global DNA damage was assessed in hemocytes using an alkaline version of the comet assay. Next, NOR sensitivity was analysed by mapping major rDNA repeat unit by fluorescence in situ hybridisation (FISH) on the same comet slides. Exposure of hemocytes to 100 μM of hydrogen peroxide ind...

  1. In Vivo RNA Interference of a Gonad-Specific Transforming Growth Factor-beta in the Pacific Oyster Crassostrea gigas

    OpenAIRE

    Huvet, Arnaud; Fleury, Elodie; Corporeau, Charlotte; Quillien, Virgile; Daniel, Jean-yves; Riviere, Guillaume; Boudry, Pierre; Fabioux, Caroline

    2012-01-01

    We investigated the role of oyster gonadal TGF beta (og-TGF beta) in the reproduction of Crassostrea gigas, using an in vivo RNA interference approach. We designed double-stranded RNA targeting og-TGF beta, which is specifically expressed in the somatic cells surrounding germ cells in the gonad of both male and female oysters. In vivo injection of this og-TGF beta dsRNA into the gonad led to knock-down phenotypes for both sexes, with significant reduction (77.52% relative to controls) of the ...

  2. Effect of phytoplankton and temperature on the reproduction of the Pacific oyster Crassostrea gigas: investigation through DEB theory

    OpenAIRE

    Bernard, Ismael; De Kermoysan, Goulwen; Pouvreau, Stephane

    2011-01-01

    DEB theory can be used to obtain a detailed description of energy allocation in organisms and the control of this allocation by temperature and food concentration. In this study, we modified the model of Bourlès et al. (2009) developed for the Pacific oyster, Crassostrea gigas, to improve the description of reproductive effort. The model was amended in two ways: a new set of parameters was incorporated and a full description of gonad construction in spring was added, with a new state variable...

  3. Growth and reproductive investment of introduced Pacific oysters Crassostrea gigas in southern European waters

    OpenAIRE

    Cardoso, J.F.M.F.; Peralta, N.R.E.; J. P. Machado; H. W. van der Veer

    2013-01-01

    Growth and reproductive investment of cultured Pacific oysters Crassostrea gigas were studied in two south-western European estuaries: the Ria de Ribadeo in Spain and the Ria Formosa in Portugal. Developing gonads were found in individuals >23.5 mm shell length in the Ria Formosa and >27.5 mm shell length in the Ria de Ribadeo. Although the amount of gonadal mass in relation to total body mass was higher in the Ria de Ribadeo, oysters from this location did not spawn completely. In contrast, ...

  4. Status of the Pacific Oyster Crassostrea gigas (Thunberg, 1793) in the western Limfjord, Denmark – Five years of population development

    DEFF Research Database (Denmark)

    Groslier, Tilde; Christensen, Helle Torp; Davids, Jens;

    2014-01-01

    The Pacific oyster, Crassostrea gigas, was introduced into the Netherlands in 1964 for aquaculture purposes and has since spread extensively in Northern European waters. Eight locations in the western part of the Limfjord, Denmark, first sampled in 2006 were revisited in 2011, to determine how the...... population of C. gigas has changed. Densities were lower at all but two locations. No differences in average shell lengths or condition indices were detected. No changes in the number or distribution of shell size classes were observed. These similarities suggest there is a single population that has not....... gigas population is not a cause for concern in the Limfjord ecosystem...

  5. Inheritance of 15 microsatellites in the Pacific oyster Crassostrea gigas: segregation and null allele identification for linkage analysis

    Institute of Scientific and Technical Information of China (English)

    LI Li; GUO Ximing; ZHANG Guofan

    2009-01-01

    Microsatellites were screened in a backcross family of the Pacific oyster, Crassostrea gigas. Fifteen microsatellite loci were distinguishable and polymorphic with 6 types of allele-combinations. Null alleles were detected in 46.7% of loci, accounting for 11.7% of the total alleles. Four loci did not segregate in Mendelian Ratios. Three linkage groups were identified among 7 of the 15 segregating loci. Fluorescence-based automated capillary electrophoresis (ABI 310 Genetic Analyzer) that used to detect the microsatellite loci, has been proved a fast, precise, and reliable method in microsatellite genotyping.

  6. The lunar-tide cycle viewed by crustacean and mollusc gatherers in the State of Paraíba, Northeast Brazil and their influence in collection attitudes

    Directory of Open Access Journals (Sweden)

    Alves Rômulo RN

    2006-01-01

    Full Text Available Abstract Traditional human communities have a wide knowledge of their environment. Collection of animals in estuarine and coastal areas are directly influenced by tidal cycles. The aim of this study is to evaluate the understanding of the tides associated with the lunar cycle held by people who gather crustaceans and molluscs in the State of Paraiba. The empirical knowledge of 20 crab gatherers and 30 mollusc gatherers was recorded through open interviews and structured questionnaires. The results showed that the gatherers have an accurate comprehension of tidal phenomenon based on their exploitation of natural resources, which perpetuates through generations.

  7. Permian bivalves of the Taciba Formation, Itararé Group, Paraná Basin, and their biostratigraphic significance

    Directory of Open Access Journals (Sweden)

    Marcello Guimarães Simões

    2012-04-01

    Full Text Available A small and poorly diversified bivalve fauna from Taciba Formation, Itararé Group, Paraná Basin (State of Santa Catarina,Mafra Municipality, is described in this paper for the first time, based on new findings. The fauna is recorded in a 30 cmthick interval of fine sandstone locally at the top of Taciba Formation, in the Butiá quarry. The studied fossil-bearing sandstonebed is a marine intercalation recording a brief eustatic rise in sea-level, probably following glacier retreat and climateamelioration at the end of a broad glacial scenario. The fauna is mainly dominated by productid brachiopods, which are notdescribed here, and rare mollusk shells (bivalves and gastropods. Two bivalve species were identified: Myonia argentinensis(Harrington, 1955, and Aviculopecten multiscalptus (Thomas, 1928. The presence of Myonia argentinensis is noteworthysince this species is also present in the Baitaca assemblage found in marine siltstones (Baitaca assemblage of theRio do Sul Formation, cropping out at the Teixeira Soares region, Paraná State. This species is also recorded in the bivalvefauna from the Bonete Formation, Pillahinco Group, Sauce Grande Basin, Buenos Aires Province, in Argentina. Hence, themarine bivalves of the Taciba Formation are associated with the transgressive event that characterizes the Eurydesma fauna,indicating a Late Asselian-Sakmarian age for the bivalve fauna. Presence of the Myonia argentinensis megadesmid speciesreinforces the Gondwanic nature of the studied fauna.

  8. Validating the Incorporation of 13C and 15N in a Shorebird That Consumes an Isotopically Distinct Chemosymbiotic Bivalve.

    Science.gov (United States)

    van Gils, Jan A; Ahmedou Salem, Mohamed Vall

    2015-01-01

    The wealth of field studies using stable isotopes to make inferences about animal diets require controlled validation experiments to make proper interpretations. Despite several pleas in the literature for such experiments, validation studies are still lagging behind, notably in consumers dwelling in chemosynthesis-based ecosystems. In this paper we present such a validation experiment for the incorporation of 13C and 15N in the blood plasma of a medium-sized shorebird, the red knot (Calidris canutus canutus), consuming a chemosymbiotic lucinid bivalve (Loripes lucinalis). Because this bivalve forms a symbiosis with chemoautotrophic sulphide-oxidizing bacteria living inside its gill, the bivalve is isotopically distinct from 'normal' bivalves whose food has a photosynthetic basis. Here we experimentally tested the hypothesis that isotope discrimination and incorporation dynamics are different when consuming such chemosynthesis-based prey. The experiment showed that neither the isotopic discrimination factor, nor isotopic turnover time, differed between birds consuming the chemosymbiotic lucinid and a control group consuming a photosynthesis-based bivalve. This was true for 13C as well as for 15N. However, in both groups the 15N discrimination factor was much higher than expected, which probably had to do with the birds losing body mass over the course of the experiment. PMID:26458005

  9. Validating the Incorporation of 13C and 15N in a Shorebird That Consumes an Isotopically Distinct Chemosymbiotic Bivalve.

    Directory of Open Access Journals (Sweden)

    Jan A van Gils

    Full Text Available The wealth of field studies using stable isotopes to make inferences about animal diets require controlled validation experiments to make proper interpretations. Despite several pleas in the literature for such experiments, validation studies are still lagging behind, notably in consumers dwelling in chemosynthesis-based ecosystems. In this paper we present such a validation experiment for the incorporation of 13C and 15N in the blood plasma of a medium-sized shorebird, the red knot (Calidris canutus canutus, consuming a chemosymbiotic lucinid bivalve (Loripes lucinalis. Because this bivalve forms a symbiosis with chemoautotrophic sulphide-oxidizing bacteria living inside its gill, the bivalve is isotopically distinct from 'normal' bivalves whose food has a photosynthetic basis. Here we experimentally tested the hypothesis that isotope discrimination and incorporation dynamics are different when consuming such chemosynthesis-based prey. The experiment showed that neither the isotopic discrimination factor, nor isotopic turnover time, differed between birds consuming the chemosymbiotic lucinid and a control group consuming a photosynthesis-based bivalve. This was true for 13C as well as for 15N. However, in both groups the 15N discrimination factor was much higher than expected, which probably had to do with the birds losing body mass over the course of the experiment.

  10. Sessile snails, dynamic genomes: gene rearrangements within the mitochondrial genome of a family of caenogastropod molluscs

    Directory of Open Access Journals (Sweden)

    Bieler Rüdiger

    2010-07-01

    uncovered major changes in gene order within a family of caenogastropod molluscs that are indicative of a highly dynamic mitochondrial genome. Studies of mitochondrial genomes at such low taxonomic levels should help to illuminate the dynamics of gene order change, since the telltale vestiges of gene duplication, translocation, and remolding have not yet been erased entirely. Likewise, gene order characters may improve phylogenetic hypotheses at finer taxonomic levels than once anticipated and aid in investigating the conditions under which sequence-based phylogenies lack resolution or prove misleading.

  11. Transcriptome of the Australian Mollusc Dicathais orbita Provides Insights into the Biosynthesis of Indoles and Choline Esters

    Directory of Open Access Journals (Sweden)

    Abdul Baten

    2016-07-01

    Full Text Available Dicathais orbita is a mollusc of the Muricidae family and is well known for the production of the expensive dye Tyrian purple and its brominated precursors that have anticancer properties, in addition to choline esters with muscle-relaxing properties. However, the biosynthetic pathways that produce these secondary metabolites in D. orbita are not known. Illumina HiSeq 2000 transcriptome sequencing of hypobranchial glands, prostate glands, albumen glands, capsule glands, and mantle and foot tissues of D. orbita generated over 201 million high quality reads that were de novo assembled into 219,437 contigs. Annotation with reference to the Nr, Swiss-Prot and Kyoto Encyclopedia of Genes and Genomes (KEGG databases identified candidate-coding regions in 76,152 of these contigs, with transcripts for many enzymes in various metabolic pathways associated with secondary metabolite biosynthesis represented. This study revealed that D. orbita expresses a number of genes associated with indole, sulfur and histidine metabolism pathways that are relevant to Tyrian purple precursor biosynthesis, and many of which were not found in the fully annotated genomes of three other molluscs in the KEGG database. However, there were no matches to known bromoperoxidase enzymes within the D. orbita transcripts. These transcriptome data provide a significant molecular resource for gastropod research in general and Tyrian purple producing Muricidae in particular.

  12. Transcriptome of the Australian Mollusc Dicathais orbita Provides Insights into the Biosynthesis of Indoles and Choline Esters.

    Science.gov (United States)

    Baten, Abdul; Ngangbam, Ajit Kumar; Waters, Daniel L E; Benkendorff, Kirsten

    2016-01-01

    Dicathais orbita is a mollusc of the Muricidae family and is well known for the production of the expensive dye Tyrian purple and its brominated precursors that have anticancer properties, in addition to choline esters with muscle-relaxing properties. However, the biosynthetic pathways that produce these secondary metabolites in D. orbita are not known. Illumina HiSeq 2000 transcriptome sequencing of hypobranchial glands, prostate glands, albumen glands, capsule glands, and mantle and foot tissues of D. orbita generated over 201 million high quality reads that were de novo assembled into 219,437 contigs. Annotation with reference to the Nr, Swiss-Prot and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases identified candidate-coding regions in 76,152 of these contigs, with transcripts for many enzymes in various metabolic pathways associated with secondary metabolite biosynthesis represented. This study revealed that D. orbita expresses a number of genes associated with indole, sulfur and histidine metabolism pathways that are relevant to Tyrian purple precursor biosynthesis, and many of which were not found in the fully annotated genomes of three other molluscs in the KEGG database. However, there were no matches to known bromoperoxidase enzymes within the D. orbita transcripts. These transcriptome data provide a significant molecular resource for gastropod research in general and Tyrian purple producing Muricidae in particular. PMID:27447649

  13. Managing marine mollusc diseases in the context of regional and international commerce: policy issues and emerging concerns.

    Science.gov (United States)

    Carnegie, Ryan B; Arzul, Isabelle; Bushek, David

    2016-03-01

    Marine mollusc production contributes to food and economic security worldwide and provides valuable ecological services, yet diseases threaten these industries and wild populations. Although the infrastructure for mollusc aquaculture health management is well characterized, its foundations are not without flaws. Use of notifiable pathogen lists can leave blind spots with regard to detection of unlisted and emerging pathogens. Increased reliance on molecular tools has come without similar attention to diagnostic validation, raising questions about assay performance, and has been accompanied by a reduced emphasis on microscopic diagnostic expertise that could weaken pathogen detection capabilities. Persistent questions concerning pathogen biology and ecology promote regulatory paralysis that impedes trade and which could weaken biosecurity by driving commerce to surreptitious channels. Solutions that might be pursued to improve shellfish aquaculture health management include the establishment of more broad-based surveillance programmes, wider training and use of general methods like histopathology to ensure alertness to emerging diseases, an increased focus on assay assessment and validation as fundamental to assay development, investment in basic research, and application of risk analyses to improve regulation. A continual sharpening of diagnostic tools and approaches and deepening of scientific knowledge is necessary to manage diseases and promote sustainable molluscan shellfish industries. PMID:26880834

  14. Causes and effects of a highly successful marine invasion : Case-study of the introduced Pacific oyster Crassostrea gigas in continental NW European estuaries

    NARCIS (Netherlands)

    Troost, Karin

    2010-01-01

    Since the 1960's, the Pacific oyster Crassostrea gigas has been introduced for mariculture at several locations within NW Europe. The oyster established itself everywhere and expanded rapidly throughout the receiving ecosystems, forming extensive and dense reef structures. It became clear that the P

  15. Causes and effects of a highly successful marine invasion: Case-study of the introduced Pacific oyster Crassostrea gigas in continental NW European estuaries

    NARCIS (Netherlands)

    Troost, K.

    2010-01-01

    Since the 1960's, the Pacific oyster Crassostrea gigas has been introduced for mariculture at several locations within NW Europe. The oyster established itself everywhere and expanded rapidly throughout the receiving ecosystems, forming extensive and dense reef structures. It became clear that the P

  16. Malacofauna marinha da região costeira do Canal de São Sebastião, SP, Brasil: Gastropoda, Bivalvia, Polyplacophora e Scaphopoda A faunal survey of the marine molluscs of the Channel of São Sebastião, SP, Brazil: Gastropoda, Bivalvia, Polyplacophora and Scaphopoda

    Directory of Open Access Journals (Sweden)

    Alvaro Esteves Migotto

    1993-01-01

    Full Text Available Um levantamento faunístico dos moluscos marinhos do Canal de São Sebastião foi realizado entre junho de 1982 e fevereiro de 1983. Um total de 195 espécies foram encontradas: 103 gastrópodes, 87 bivalves, 4 quitons e 1 escafópodo. 140 espécies pertecem a fauna caribeana, 22 são cosmopolitas ou circuntropicais, 13 são endêmicas da costa brasileira e 10 pertecem à fauna patagônica. A maioria das espécies foi encontrada na região entremarés. São também listadas outras 142 espécies de moluscos registradas por outros autores para a região e não reencontradas. Foi notada uma redução no número de espécies ao se comparar os dados do presente trabalho com dados mais recentes, obtidos por outros autores. Levanta-se a hipótese de que esta situação é devida a poluição crônica e outros impactos ambientais.Between June 1982 and February 1983 a survey of the marine molluscs of the Channel of São Sebastião, State of São Paulo, was carried out A total of 195 species were found: 103 gastropods, 87 bivalves, 4 chitons, and 1 scaphopod. 140 species belong to the Caribbean fauna, 22 are circumtropical or worldwide in distribution, 13 are endemic to the Brazilian coast, and 10 belong to the Patagonian fauna. Most species (77,6 % were found in the intertidal zone. 142 species, recorded for the region by other authors and not found in the present survey, are also listed. A reduction in the number of species was also observed comparing the present data (1982-1983 with more recent data from other authors (1987-1989. This situation is probably due to chronic pollution and other environmental impacts.

  17. Differential reproductive strategies of two bivalves in the Dutch Wadden Sea

    Science.gov (United States)

    Cardoso, Joana F. M. F.; Witte, Johannes IJ.; van der Veer, Henk W.

    2009-08-01

    Cerastoderma edule and Mya arenaria are two common bivalve species in European waters. Longevity and maximum size are much greater in the latter species. Because comparison of species life-history strategies states that a long life span (i.e. high annual survival) generally goes with lower fecundity, we hypothesise that reproductive output would be lower in M. arenaria than in C. edule. In the present paper, we studied the reproductive strategies of these two species in an intertidal and a subtidal area of the western Dutch Wadden Sea, by following seasonal changes in absolute and relative weights of somatic and gonadal tissues in these bivalves. Starting of spawning was similar in the two species, around May, except for intertidal M. arenaria, which initiated spawning in August. Individual energy investment in reproduction was similar for the two species but, unlike M. arenaria, C. edule spawned completely, releasing all energy of gonadal mass in the form of gametes. Mya arenaria used the gonad not only for reproduction but also for storage. In the intertidal area, we found a trade-off between longevity and reproduction, i.e. maximum reproductive output (expressed as a proportion of body mass) was higher in C. edule than in M. arenaria. However, since body size is larger and life span longer in M. arenaria than in C. edule, mean lifetime reproductive output per individual must be higher in the first than in the latter. Based on the differences in reproductive strategies of these two species, we hypothesise that the negative effects of warming climate on bivalve population dynamics in the Wadden Sea will be stronger in C. edule than in M. arenaria.

  18. Caspase-3 serves as an intracellular immune receptor specific for lipopolysaccharide in oyster Crassostrea gigas.

    Science.gov (United States)

    Xu, Jiachao; Jiang, Shuai; Li, Yiqun; Li, Meijia; Cheng, Qi; Zhao, Depeng; Yang, Bin; Jia, Zhihao; Wang, Lingling; Song, Linsheng

    2016-08-01

    Apoptosis is a form of programmed cell death process controlled by a family of cysteine proteases called caspases, which plays a crucial role in the immune system homeostasis. The apoptosis and the detailed regulation mechanism have been well studied in vertebrate, but the information in lower animals, especially invertebrates, is still very limited. In the present study, Caspase-3 in the Pacific oyster Crassostrea gigas (designated CgCaspase-3) was enriched by lipopolysaccharide (LPS) affinity chromatography and further identified by MALDI-TOF/TOF-mass spectrometry. The binding activity of CgCaspase-3 to LPS was confirmed by enzyme-linked immunosorbent assay, and surface plasmon resonance analysis revealed its high binding specificity and moderate binding affinity (KD = 1.08 × 10(-6) M) to LPS. The recombinant CgCaspase-3 exhibited high proteolytic activity to substrate Ac-DEVD-pNA and relatively weak activity to substrate Ac-DMQD-pNA and Ac-VDQQD-pNA. The binding of CgCaspase-3 to LPS significantly inhibited its proteolytic activity toward AC-DEVD-pNA in vitro. The over-expression of CgCaspase-3 leaded to the phosphatidylserine exposure on the external plasma membrane and the cleavage of poly (ADP-ribose) polymerase, which reduced cell viability, and finally induced cell apoptosis. But the cell apoptosis mediated by CgCaspase-3 in vivo was significantly inhibited by the treatment of LPS. These results collectively indicated that CgCaspase-3 could serve as an intracellular LPS receptor, and the interaction of LPS with CgCaspase-3 specifically inhibited the cell apoptosis induced by CgCaspase-3. PMID:26993662

  19. Exploitable Lipids and Fatty Acids in the Invasive Oyster Crassostrea gigas on the French Atlantic Coast

    Directory of Open Access Journals (Sweden)

    Flore Dagorn

    2016-05-01

    Full Text Available Economic exploitation is one means to offset the cost of controlling invasive species, such as the introduced Pacific oyster (Crassostrea gigas Thunberg on the French Atlantic coast. Total lipid and phospholipid (PL fatty acids (FAs and sterols were examined in an invasive population of C. gigas in Bourgneuf Bay, France, over four successive seasons, with a view to identify possible sources of exploitable substances. The total lipid level (% dry weight varied from 7.1% (winter to 8.6% (spring. Of this, PLs accounted for 28.1% (spring to 50.4% (winter. Phosphatidylcholine was the dominant PL throughout the year (up to 74% of total PLs in winter. Plasmalogens were identified throughout the year as a series of eleven dimethylacetals (DMAs with chain lengths between C16 and C20 (up to 14.5% of PL FAs + DMAs in winter. Thirty-seven FAs were identified in the PL FAs. Eicosapentaenoic acid (20:5n-3 EPA/7.53% to 14.5% and docosahexaenoic acid (22:6n-3 DHA/5.51% to 9.5% were the dominant polyunsaturated FAs in all seasons. Two non-methylene-interrupted dienoic (NMID FAs were identified in all seasons: 7,13-docosadienoic and 7,15-docosadienoic acids, the latter being present at relatively high levels (up to 9.6% in winter. Twenty free sterols were identified, including cholesterol at 29.9% of the sterol mixture and about 33% of phytosterols. C. gigas tissues thus contained exploitable lipids for health benefits or as a potential source of high-quality commercial lecithin.

  20. Antioxidant deficit in gills of Pacific oyster (Crassostrea gigas) exposed to chlorodinitrobenzene increases menadione toxicity

    International Nuclear Information System (INIS)

    Disturbances in antioxidant defenses decrease cellular protection against oxidative stress and jeopardize cellular homeostasis. To knock down the antioxidant defenses of Pacific oyster Crassostrea gigas, animals were pre-treated with 1-chloro-2,4-dinitrobenzene (CDNB) and further challenged with pro-oxidant menadione (MEN). CDNB pre-treatment (10 μM for 18 h) was able to consume cellular thiols in gills, decreasing GSH (53%) and decrease protein thiols (25%). CDNB pre-treatment also disrupted glutathione reductase and thioredoxin reductase activity in the gills, but likewise strongly induced glutathione S-transferase activity (270% increase). Surprisingly, hemocyte viability was greatly affected 24 h after CDNB removal, indicating a possible vulnerability of the oyster immune system to electrophilic attack. New in vivo approaches were established, allowing the identification of higher rates of GSH–CDNB conjugate export to the seawater and enabling the measurement of the organic peroxide consumption rate. CDNB-induced impairment in antioxidant defenses decreased the peroxide removal rate from seawater. After showing that CDNB decreased gill antioxidant defenses and increased DNA damage in hemocytes, oysters were further challenged with 1 mM MEN over 24 h. MEN treatment did not affect thiol homeostasis in gills, while CDNB pre-treated animals recovered GSH and PSH to the control level after 24 h of depuration. Interestingly, MEN intensified GSH and PSH loss and mortality in CDNB-pre-treated animals, showing a clear synergistic effect. The superoxide-generating one-electron reduction of MEN was predominant in gills and may have contributed to MEN toxicity. These results support the idea that antioxidant-depleted animals are more susceptible to oxidative attack, which can compromise survival. Data also corroborate the idea that gills are an important detoxifying organ, able to dispose of organic peroxides, induce phase II enzymes, and efficiently export GSH

  1. The inhibitory role of γ-aminobutyric acid (GABA) on immunomodulation of Pacific oyster Crassostrea gigas.

    Science.gov (United States)

    Li, Meijia; Qiu, Limei; Wang, Lingling; Wang, Weilin; Xin, Lusheng; Li, Yiqun; Liu, Zhaoqun; Song, Linsheng

    2016-05-01

    γ-aminobutyric acid (GABA) is an inhibitory neurotransmitter to suppress the immune-mediated pro-inflammatory reactions, and it has been used in the treatment of many inflammation-related diseases in vertebrates, while its immunomodulatory role in invertebrates has never been reported. In the present study, GABA was found to exist in the hemolymph of Pacific oyster Crassostrea gigas, and its concentration decreased slightly from 8.00 ± 0.37 μmol L(-1) at normal condition to 7.73 ± 0.15 μmol L(-1) at 6 h after LPS stimulation, and then increased to 9.34 ± 0.15 μmol L(-1), 8.86 ± 0.68 μmol L(-1) at 12 h and 48 h, respectively. After LPS stimulation, the mRNA expressions of pro-inflammatory cytokines (CgIL-17 and CgTNF) and immune effectors (CgSOD and CgBPI), and the protein expression of NOS increased significantly, and these increased trends were remarkably inhibited by GABA stimulation. At the same time, the phagocytosis rate and apoptosis rate of immunocytes also increased obviously after LPS stimulation, whereas the increase was repressed with the addition of GABA. The results collectively demonstrated that GABA was an indispensable inhibitory agent for both humoral and cellular immune response, which mainly functioned at the late phase of immune response to avoid the excess immune reactions and maintain the immune homeostasis. PMID:26975413

  2. Transcriptional changes in Crassostrea gigas oyster spat following a parental exposure to the herbicide diuron.

    Science.gov (United States)

    Rondon, R; Akcha, F; Alonso, P; Menard, D; Rouxel, J; Montagnani, C; Mitta, G; Cosseau, C; Grunau, C

    2016-06-01

    The Pacific oyster Crassostrea gigas is the main oyster species produced in the world, and a key coastal economic resource in France. High mortalities affect Pacific oysters since 2008 in France and Europe. Their origins have been attributed to a combination of biotic and abiotic factors, underlining the importance of environment quality. The impact of water pollution has been pointed out and one of the pollutants, the genotoxic herbicide diuron, occurs at high concentrations all along the French coasts. Previous work has revealed that a parental exposure to diuron had a strong impact on hatching rates and offspring development even if spats were not exposed to diuron themselves. In this study, we explored for the first time the transcriptional changes occurring in oyster spats (non exposed) originating from genitors exposed to an environmentally relevant concentration of diuron during gametogenesis using the RNAseq methodology. We identified a transcriptomic remodeling revealing an effect of the herbicide. Different molecular pathways involved in energy production, translation and cell proliferation are particularly disturbed. This analysis revealed modulated candidate genes putatively involved in response to oxidative stress and mitochondrial damage in offspring of genitors exposed to diuron. Complementary measures of the activity of enzymes involved in these latter processes corroborate the results obtained at the transcriptomic level. In addition, our results suggested an increase in energy production and mitotic activity in 5-month-spats from diuron-exposed genitors. These results could correspond to a "catch-up growth" phenomenon allowing the spats from diuron-exposed genitors, which displayed a growth delay at 3 months, to gain a normal size when they reach the age of 6 months. These results indicate that exposure to a concentration of diuron that is frequently encountered in the field during the oyster's gametogenesis stage can impact the next generation

  3. The curious case of eastern oyster Crassostrea virginica stock status in Apalachicola Bay, Florida

    Directory of Open Access Journals (Sweden)

    William E. Pine III

    2015-09-01

    Full Text Available The Apalachicola Bay, Florida, eastern oyster (Crassostrea virginica industry has annually produced about 10% of the U.S. oyster harvest. Today's simple individual-operator, hand-tonging, small-vessel fishery is remarkably similar to the one that began in the 1800s. Unprecedented attention is currently being given to the status of oyster resources in Apalachicola Bay because this fishery has become central to the decision making related to multistate water disputes in the southeastern United States, as well as millions of dollars in funding for restoration programs related to the Deepwater Horizon oil spill. The oyster fishery collapsed in 2012, leading to large economic losses and community concerns over the current and future status of oyster resources, ecosystem health, and local economic opportunities. We used best available data to assess what mechanism(s may have led to the collapse of the Apalachicola Bay oyster fishery. We then assessed the efficacy of alternative management strategies (e.g., restoration, fishery closure to accelerate oyster population recovery. Our results suggest that the Apalachicola Bay oyster population is not overfished in the sense that recruitment has been limited by harvest, but that the 2012 collapse was driven by lower-than-average numbers and/or poor survival of juvenile oysters in the years preceding the collapse. This reduction in recruitment not only reduced the biomass of oysters available to harvest, but from a population resilience perspective, likely reduced the amount of dead shell material available as larval settlement area. Although the Apalachicola Bay oyster fishery has proven resilient over its >150-year history to periods of instability, this fishery now seems to be at a crossroads in terms of continued existence and possibly risks an irreversible collapse. How to use the restoration funds available, and which restoration and management practices to follow, are choices that will determine the

  4. Effect of carbonate chemistry alteration on the early embryonic development of the Pacific oyster (Crassostrea gigas.

    Directory of Open Access Journals (Sweden)

    Frédéric Gazeau

    Full Text Available Ocean acidification, due to anthropogenic CO₂ absorption by the ocean, may have profound impacts on marine biota. Calcareous organisms are expected to be particularly sensitive due to the decreasing availability of carbonate ions driven by decreasing pH levels. Recently, some studies focused on the early life stages of mollusks that are supposedly more sensitive to environmental disturbances than adult stages. Although these studies have shown decreased growth rates and increased proportions of abnormal development under low pH conditions, they did not allow attribution to pH induced changes in physiology or changes due to a decrease in aragonite saturation state. This study aims to assess the impact of several carbonate-system perturbations on the growth of Pacific oyster (Crassostrea gigas larvae during the first 3 days of development (until shelled D-veliger larvae. Seawater with five different chemistries was obtained by separately manipulating pH, total alkalinity and aragonite saturation state (calcium addition. Results showed that the developmental success and growth rates were not directly affected by changes in pH or aragonite saturation state but were highly correlated with the availability of carbonate ions. In contrast to previous studies, both developmental success into viable D-shaped larvae and growth rates were not significantly altered as long as carbonate ion concentrations were above aragonite saturation levels, but they strongly decreased below saturation levels. These results suggest that the mechanisms used by these organisms to regulate calcification rates are not efficient enough to compensate for the low availability of carbonate ions under corrosive conditions.

  5. Exploitable Lipids and Fatty Acids in the Invasive Oyster Crassostrea gigas on the French Atlantic Coast.

    Science.gov (United States)

    Dagorn, Flore; Couzinet-Mossion, Aurélie; Kendel, Melha; Beninger, Peter G; Rabesaotra, Vony; Barnathan, Gilles; Wielgosz-Collin, Gaëtane

    2016-01-01

    Economic exploitation is one means to offset the cost of controlling invasive species, such as the introduced Pacific oyster (Crassostrea gigas Thunberg) on the French Atlantic coast. Total lipid and phospholipid (PL) fatty acids (FAs) and sterols were examined in an invasive population of C. gigas in Bourgneuf Bay, France, over four successive seasons, with a view to identify possible sources of exploitable substances. The total lipid level (% dry weight) varied from 7.1% (winter) to 8.6% (spring). Of this, PLs accounted for 28.1% (spring) to 50.4% (winter). Phosphatidylcholine was the dominant PL throughout the year (up to 74% of total PLs in winter). Plasmalogens were identified throughout the year as a series of eleven dimethylacetals (DMAs) with chain lengths between C16 and C20 (up to 14.5% of PL FAs + DMAs in winter). Thirty-seven FAs were identified in the PL FAs. Eicosapentaenoic acid (20:5n-3 EPA/7.53% to 14.5%) and docosahexaenoic acid (22:6n-3 DHA/5.51% to 9.5%) were the dominant polyunsaturated FAs in all seasons. Two non-methylene-interrupted dienoic (NMID) FAs were identified in all seasons: 7,13-docosadienoic and 7,15-docosadienoic acids, the latter being present at relatively high levels (up to 9.6% in winter). Twenty free sterols were identified, including cholesterol at 29.9% of the sterol mixture and about 33% of phytosterols. C. gigas tissues thus contained exploitable lipids for health benefits or as a potential source of high-quality commercial lecithin. PMID:27231919

  6. Inter-site differences of zinc susceptibility of the oyster Crassostrea hongkongensis

    International Nuclear Information System (INIS)

    Highlights: ► Zn sensitivity and detoxification in oysters are related to the history of metal exposure. ► The lethal threshold concentration of total body Zn varied significantly among oyster populations. ► Total body Zn concentration could not serve as a suitable toxicity indicator in oysters. ► Zn toxicity is related to a threshold concentration of metabolically available metal. -- Abstract: Understanding the underlying mechanisms governing metal toxicity is crucial for predicting the risks and effects of metal pollutants. We hypothesized that metal toxicity is related to a threshold concentration of metabolically available metal but not to the total body metal concentration. Following a two-month laboratory Zn exposure, we characterized mortality and Zn bioaccumulation and subcellular partitioning in the oyster Crassostrea hongkongensis sampled from three sites with contrasting histories of Zn exposure and one multiple-metal contaminated site. Large differences in Zn sensitivity, lethal body concentration, and detoxification capability between sites were observed. Specifically, the oysters from the highly Zn-contaminated site were more tolerant to Zn exposure than those from the relatively clean ones, and the former accumulated and detoxified more Zn and had a significantly higher lethal body Zn concentration. The accumulation of Zn in the metabolically available pool (operationally defined as the metal-sensitive fraction) in the oysters from the multiple-metal contaminated site was relatively fast, and correspondingly they were highly sensitive to Zn exposure. The lethal threshold concentration of total body Zn varied significantly within the four sites, and thus total body Zn concentration could not serve as a suitable toxicity indicator. Importantly, Zn accumulation within the operationally defined metabolically available pool better explained variances in mortality than Zn accumulation in the whole body. Our results suggested that Zn toxicity is

  7. Antioxidant deficit in gills of Pacific oyster (Crassostrea gigas) exposed to chlorodinitrobenzene increases menadione toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Trevisan, Rafael; Arl, Miriam [Departamento de Bioquimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Sacchet, Cassia Lopes [Universidade do Oeste do Estado de Santa Catarina, 89600-000 Joacaba, SC (Brazil); Engel, Cristiano Severino; Danielli, Naissa Maria; Mello, Danielle Ferraz [Departamento de Bioquimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Brocardo, Caroline [Universidade do Oeste do Estado de Santa Catarina, 89600-000 Joacaba, SC (Brazil); Maris, Angelica Francesca [Departamento de Biologia Celular, Embriologia e Genetica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Dafre, Alcir Luiz, E-mail: alcir@ccb.ufsc.br [Departamento de Bioquimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil)

    2012-02-15

    Disturbances in antioxidant defenses decrease cellular protection against oxidative stress and jeopardize cellular homeostasis. To knock down the antioxidant defenses of Pacific oyster Crassostrea gigas, animals were pre-treated with 1-chloro-2,4-dinitrobenzene (CDNB) and further challenged with pro-oxidant menadione (MEN). CDNB pre-treatment (10 {mu}M for 18 h) was able to consume cellular thiols in gills, decreasing GSH (53%) and decrease protein thiols (25%). CDNB pre-treatment also disrupted glutathione reductase and thioredoxin reductase activity in the gills, but likewise strongly induced glutathione S-transferase activity (270% increase). Surprisingly, hemocyte viability was greatly affected 24 h after CDNB removal, indicating a possible vulnerability of the oyster immune system to electrophilic attack. New in vivo approaches were established, allowing the identification of higher rates of GSH-CDNB conjugate export to the seawater and enabling the measurement of the organic peroxide consumption rate. CDNB-induced impairment in antioxidant defenses decreased the peroxide removal rate from seawater. After showing that CDNB decreased gill antioxidant defenses and increased DNA damage in hemocytes, oysters were further challenged with 1 mM MEN over 24 h. MEN treatment did not affect thiol homeostasis in gills, while CDNB pre-treated animals recovered GSH and PSH to the control level after 24 h of depuration. Interestingly, MEN intensified GSH and PSH loss and mortality in CDNB-pre-treated animals, showing a clear synergistic effect. The superoxide-generating one-electron reduction of MEN was predominant in gills and may have contributed to MEN toxicity. These results support the idea that antioxidant-depleted animals are more susceptible to oxidative attack, which can compromise survival. Data also corroborate the idea that gills are an important detoxifying organ, able to dispose of organic peroxides, induce phase II enzymes, and efficiently export GSH

  8. Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Praveen Kumar, M.K., E-mail: here.praveen@gmail.com [Department of Zoology, Goa University, Goa 403206 (India); Shyama, S.K., E-mail: skshyama@gmail.com [Department of Zoology, Goa University, Goa 403206 (India); Sonaye, B.S. [Department of Radiation Oncology, Goa Medical College, Goa (India); Naik, U Roshini; Kadam, S.B.; Bipin, P.D.; D’costa, A. [Department of Zoology, Goa University, Goa 403206 (India); Chaubey, R.C. [Radiation Biology and Health Science Division, Bhabha Atomic Research Centre, Mumbai (India)

    2014-05-01

    Highlights: • Possible genotoxic effect of accidental exposure of aquatic fauna to γ radiation. • Relative sensitivity of bivalves to γ radiation is also analyzed using comet assay. • γ radiation induced significant genetic damage in both the species of bivalves. • P. malabarica and M. casta exhibited a similar level of sensitivity to γ radiation. • Comet assay may be used as a biomarker for the environmental biomonitoring. - Abstract: Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of ‘Comet assay’ for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in

  9. Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay

    International Nuclear Information System (INIS)

    Highlights: • Possible genotoxic effect of accidental exposure of aquatic fauna to γ radiation. • Relative sensitivity of bivalves to γ radiation is also analyzed using comet assay. • γ radiation induced significant genetic damage in both the species of bivalves. • P. malabarica and M. casta exhibited a similar level of sensitivity to γ radiation. • Comet assay may be used as a biomarker for the environmental biomonitoring. - Abstract: Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of ‘Comet assay’ for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in

  10. The use of bivalves as bio-indicators in the assessment of marine pollution along a coastal area

    International Nuclear Information System (INIS)

    The assessment of environmental pollution of the coastal areas of the Malaysian Peninsula was done by analyzing the contents of the heavy and trace elements in the bivalves blood clams (Anadara granosa) and green mussels (Perna viridis) and sediments at twenty-two sampling stations to look for prevailing trends. Heavy and trace elements analyzed in this study were As, Cd, Cr, Cu, Pb, Se and Zn. Two techniques, namely the neutron activation analysis (NAA) and atomic absorption spectrophotometry (AAS) were used in the quantitative determination of the heavy metals while Marine Sediment Reference Material (BCSS) and Lobster Hepatopancreas (TORT-1) provided the certified reference materials in the quality assurance control. The potential use of these bivalves as suitable bio-indicators was evaluated from correlation tests based on the concentrations of heavy and trace elements in the sediment-metals system to those in the bivalves. (author)

  11. Bioaccumulation, Toxicity And Decontamination Studies Of Some Radioisotopes From Radioactive Polluted Water By The Bivalve Carotol Carotol

    International Nuclear Information System (INIS)

    In this study, the bivalve Caelatura caelatura was examined as radiobio-indicator for some radioisotopes namely 134Cs and60Co in polluted water. The uptake process was followed at different concentrations of the radioisotope solutions and the concentration factor values were calculated. Studies of the accumulation of these radioisotopes and their toxic effects on survival of these bivalves were followed for six weeks and also the lethal dose (LD50) was calculated. Decontamination studies were also performed in water and ethylene diamine tetra acetic acid (EDTA). The results showed that the bivalve Caelatura caelatura can be considered as good radiobioindicator for some radioisotopes in polluted water due to its high concentration factor values and high tolerant for radioisotopes solutions.

  12. Bivalve growth rate and isotopic variability across the Barents Sea Polar Front

    Science.gov (United States)

    Carroll, Michael L.; Ambrose, William G.; Locke V, William L.; Ryan, Stuart K.; Johnson, Beverly J.

    2014-02-01

    Analysis of bivalve shell increments provides a means to reconstruct long-term patterns in growth histories and assess factors that regulate marine ecosystems, while tissue stable isotopes are indicators of food sources and trophic dynamics. We examined shell growth patterns and tissue stable isotopic composition (δ13C and δ15N) of the hairy cockle (Ciliatocardium ciliatum) in the northwest Barents Sea to evaluate the influence of different water masses and the Polar Front on growth rates and food sources and to assess the influence of climatic variability on ecological processes over seasonal to decadal scales. Shell growth rates were highest in Atlantic water, intermediate in Arctic water, and lowest at the Polar Front. Temporal patterns of ontogenetically-adjusted growth (SGI) were negatively correlated with the Atlantic Multidecadal Oscillation (AMO), local precipitation and ice-free days. The highest growth occurred during colder periods with more sea ice, while lower growth was associated with warmer periods and less sea ice. Stable isotope values of lipid-extracted tissues from Atlantic water cockles were enriched in δ13C by up to 2.1‰ and δ15N by 1.5‰ compared to animals from Arctic waters. Distinct seasonal and water mass variations in stable isotopic values reflect spatial and temporal variability in food supplies to the bivalves in this region on small spatial scales. Overall, Atlantic waters supported the highest growth rates, the most complex trophic webs, and the greatest sensitivity to interannual variability in environmental conditions. Bivalves from Arctic waters were the most distinct of the three groups in their response to regional climate forcing and local environmental manifestations of those conditions. The Polar Front exhibits growth and isotopic characteristics predominantly of the Atlantic domain. These results demonstrate that integrating results of sclerochronological and stable isotopic analyses of benthic bivalves provide

  13. Bivalve aquaculture transfers in Atlantic Europe. Part A: Transfer activities and legal framework

    DEFF Research Database (Denmark)

    Muehlbauer, F.; Fraser, D.; Brenner, M.; Van Nieuwenhove, K.; Buck, B.H.; Strand, O.; Mazurié, J.; Thorarinsdottir, G.; Dolmer, Per; O`Beirn, F.; Sanchez-Mata, A.; Flimlin, G.; Kamermans, P.

    2014-01-01

    of exotic species around the world. Threats due to the transfer and introduction of species have been identified and a range of global and regional agreements, guidelines, standards and statutes to minimize effects have been established. Yet whether such regulations can protect and conserve the......Intentional transfers of numerous bivalve species have had a long tradition and are commonly conducted along the European Atlantic coast. However numerous studies have concluded that intentional transfer of species for aquaculture purposes is one of the most principal vectors for the introduction...

  14. 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

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

    OpenAIRE

    Faust, Christina; Stallknecht, David; Swayne, David; Brown, Justin

    2009-01-01

    Avian influenza (AI) viruses are believed to be transmitted within wild aquatic bird populations through an indirect faecal–oral route involving contaminated water. This study examined the influence of filter-feeding bivalves, Corbicula fluminea, on the infectivity of AI virus in water. Clams were placed into individual flasks with distilled water inoculated 1:100 with a low pathogenic (LP) AI virus (A/Mallard/MN/190/99 (H3N8)). Viral titres in water with clams were significantly lower at 24 ...

  16. Mollusc shells as archival indicators of metal contamination in the Australian antarctic marine environment

    International Nuclear Information System (INIS)

    Full text: Although considered by many to be a pristine environment past activities in Antarctica have caused localised contamination. In particular, the practice of disposing of station waste in open tips adjacent to the seashore has caused heavy metals to migrate to the marine environment. Times have changed and these practices are no longer permitted. Under international agreements, such as the Protocol on Environmental Protection to the Antarctic Treaty System, operators are now required to clean-up these sites so long as the act of clean-up does not cause greater environmental harm than leaving them where they are. The Australian Antarctic Division has embarked on a program to develop techniques for clean-up and remediation of disused waste disposal sites and is also developing techniques for monitoring the environment to ensure that clean-up does not cause greater environmental harm. The Antarctic clam, Laternula elliptica, is common in near shore sediments around the entire coast of Antarctica. It is a filter feeder that extracts suspended sediments from the water column and has been suggested as a candidate for mussel watch-type monitoring in Antarctica. Contaminants in waste disposal tips in Antarctica are likely to be mobilised in pulses caused by the seasonal flush of melting snow as it passes through the contaminated material. As a filter feeder Laternula will be exposed to the highest concentrations of contaminants while they remain in suspension. If contaminants are sequestered into the shells of the bivalve and if their levels in the shell can be analysed in relation to the annual growth rings then they may prove to be a useful archive of past environmental contamination. Specimens of Laternula were exposed to known concentrations of copper and cadmium under aquarium conditions in Antarctica to understand accumulation and depuration rates in the soft tissues. This information is used to assist interpretation of concentrations in animals collected

  17. Adaptive morphologies and guild structure in a high-diversity bivalve fauna from an early Campanian rocky shore, Ivö Klack (Sweden)

    DEFF Research Database (Denmark)

    Sørensen, Anne Mehlin; Surlyk, Finn; Jagt, John W. M.

    2012-01-01

    The bivalve fauna from a late early Campanian rocky shore at Ivö Klack (southern Sweden), comprises just over sixty species, a very high diversity in comparison to other Late Cretaceous and modern rocky shore bivalve assemblages. This high diversity is here considered to represent a reliable census...... of the fauna; only in part can it be explained by the cumulative effect of generations of bivalves inhabiting this coastal environment. The high density and diversity and the wide range of shell morphologies allow interpretation of different modes of life in this variable environment with many...... from adjacent environments. It includes some of the most northerly known, very small rudistid bivalves, in addition to the oldest known occurrences of Mytilus and Barbatia in association with rocky shores. Bivalves constituted the most important invertebrate group inhabiting the late early Campanian...

  18. Organochlorine pesticides in Piracicaba river basin (São Paulo/Brazil: a survey of sediment, bivalve and fish

    Directory of Open Access Journals (Sweden)

    Daniela Mariano Lopes da Silva

    2008-01-01

    Full Text Available The main objective of this paper was to evaluate the level of occurrence of the organochlorine compounds in samples of sediments, bivalves and two fish species collected in the Piracicaba River basin (São Paulo, Brazil. The isomers alpha and gamma of HCH and Heptachlor were most frequently detected in samples of sediments and specimens of bivalve and fish. Therefore, although the levels of these compounds found were not critically high, they are still found in the environment. This fact suggests that they are still being used, despite the fact that the use of these compounds was outlawed more than twenty years ago.

  19. Mollusc succession of a prehistoric settlement area during the Holocene: A case study of the České středohoří Mountains (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Juřičková, L.; Horáčková, J.; Jansová, A.; Ložek, Vojen

    2013-01-01

    Roč. 23, č. 12 (2013), s. 1811-1823. ISSN 0959-6836 Institutional support: RVO:67985831 Keywords : České středohoří Mountains * Holocene * mollusc succession * prehistoric settlement * radiocarbon AMS dating Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.794, year: 2013

  20. Evaluation of the effects of candidate molluscicides on two nontarget bivalves

    Science.gov (United States)

    Waller, D.L.; Marking, L.L.; Rach, J.J.

    1992-01-01

    A variety of molluscicides have been proposed for use in control of zebra mussels (Dreissena polymorpha), but their effect on nontarget aquatic organisms has not been evaluated. Standard methods were adapted for assessing the toxicity of candidate molluscicides to two nontarget bivalves. Fingernail clams, Musculium transversum, and the fawnfoot mussel, Truncilla donaciformis, were selected to represent the two families of native bivalves. Test organisms were collected from pools 6 to 9 of the Upper Mississippi River near La Crosse, WI. Static acute toxicity tests were conducted for 48 hours followed by a 96-hour monitoring period in untreated water to more fully assess survival and mortality. Toxicity data were analyzed by probit analysis to give LC sub(50) values and 95% confidence limits. The same chemicals as those tested at Ohio State University were evaluated against zebra mussels. Results from these studies and those conducted at Ohio State University will be used to evaluate the effectiveness of chemicals in zebra mussel control and their potential hazard to nontarget organisms.

  1. Assessing phototoxicity of petroleum using the bivalve Mulinia lateralis and the mysid Mysidopsis bahia

    International Nuclear Information System (INIS)

    One of the major inputs of PAHs in the marine environment is petroleum products. A large and often catastrophic source of petroleum is an oil spill, which releases concentrated quantities of PAHs into the water column. Intermediate molecular weight compounds remain in the water column for a relatively extended length of time. These compounds include phototoxic PAHs such as anthracene, fluoranthene, pyrene, and their substituted derivatives. Assessments of the environmental impact of marine oil spills have not included phototoxicity tests using pelagic larvae of benthic invertebrates. In this study, the photoreactive toxicity of individual PAHs, including anthracene, pyrene, and fluoranthene, were determined using the bivalve, Mulinia lateralis and the mysid, Mysidopsis bahia. Ultraviolet light exposures increased toxicity relative to fluorescent light for both species but a particularly dramatic response was seen using M. lateralis embryos. This species was relatively insensitive when exposed under fluorescent lights, but exhibited up to a 4,000 fold increase in toxicity under ultraviolet lights. Exposures with different types of petroleum (e.g., fuel oil number-sign 2 and crude oil) under fluorescent and ultraviolet light will demonstrate the utility of this bivalve and mysid for assessing oil spill-related acute and sublethal toxicity in the marine environment

  2. Ocean acidification increases cadmium accumulation in marine bivalves: a potential threat to seafood safety

    Science.gov (United States)

    Shi, Wei; Zhao, Xinguo; Han, Yu; Che, Zhumei; Chai, Xueliang; Liu, Guangxu

    2016-01-01

    To date, the effects of ocean acidification on toxic metals accumulation and the underlying molecular mechanism remains unknown in marine bivalve species. In the present study, the effects of the realistic future ocean pCO2 levels on the cadmium (Cd) accumulation in the gills, mantle and adductor muscles of three bivalve species, Mytilus edulis, Tegillarca granosa, and Meretrix meretrix, were investigated. The results obtained suggested that all species tested accumulated significantly higher Cd (p health risk of Cd (based on the estimated target hazard quotients, THQ) via consumption of M. meretrix at pH 7.8 and 7.4 significantly increased 1.21 and 1.32 times respectively, suggesting a potential threat to seafood safety. The ocean acidification-induced increase in Cd accumulation may have occurred due to (i) the ocean acidification increased the concentration of Cd and the Cd2+/Ca2+ in the seawater, which in turn increased the Cd influx through Ca channel; (ii) the acidified seawater may have brought about epithelia damage, resulting in easier Cd penetration; and (iii) ocean acidification hampered Cd exclusion.

  3. Traces (ichnospecies Oichnus paraboloides of predatory gastropods on bivalve shells from the Seogwipo Formation, Jejudo, Korea

    Directory of Open Access Journals (Sweden)

    Dal-Yong Kong

    2015-12-01

    Full Text Available Circular to subcircular drill holes were identified on the bivalve shells collected from the Seogwipo Formation, Jejudo, Korea. A great majority of the drill holes (>70% were found on the surfaces of a bivalve species Glycymeris rotunda. They are characterized by a beveled sharp edge and paraboloid in cross section with larger outer borehole diameter (OBD; mean 4.21 mm and smaller inner borehole diameter (mean 2.94 mm. Walls of the drill holes are generally smooth, and walls ornamented with etched relief-like structures were also recognized. A slightly raised central boss observed in an incomplete specimen may indicate a failure of predator’s attack. All drill holes collected are classified as a single ichnospecies Oichnus paraboloides Bromley, 1981. They are interpreted as boring traces produced by predatory gastropods, particularly naticid gastropods. Most O. paraboloides boreholes are observed in the central area of shell surfaces; a few boreholes lie marginally, which may reflect a borehole-site selectivity. No correlation between size of prey (shell height and size of predator (OBD is recognized. It is likely, however, that drilled shells of about 30 mm in height represent optimal prey size for naticid predators that lived in a benthic Seogwipo community.

  4. Bivalve immunity and response to infections: Are we looking at the right place?

    Science.gov (United States)

    Allam, Bassem; Pales Espinosa, Emmanuelle

    2016-06-01

    Significant progress has been made in the understanding of cellular and molecular mediators of immunity in invertebrates in general and bivalve mollusks in particular. Despite this information, there is a lack of understanding of factors affecting animal resistance and specific responses to infections. This in part results from limited consideration of the spatial (and to some extent temporal) heterogeneity of immune responses and very limited information on host-pathogen (and microbes in general) interactions at initial encounter/colonization sites. Of great concern is the fact that most studies on molluscan immunity focus on the circulating hemocytes and the humoral defense factors in the plasma while most relevant host-microbe interactions occur at mucosal interfaces. This paper summarizes information available on the contrasting value of information available on focal and systemic immune responses in infected bivalves, and highlights the role of mucosal immune factors in host-pathogen interactions. Available information underlines the diversity of immune effectors at molluscan mucosal interfaces and highlights the tailored immune response to pathogen stimuli. This context raises fascinating basic research questions around host-microbe crosstalk and feedback controls of these interactions and may lead to novel disease mitigation strategies and improve the assessment of resistant crops or the screening of probiotic candidates. PMID:27004953

  5. A kinetic approach to assess oxidative metabolism related features in the bivalve Mya arenaria.

    Science.gov (United States)

    González, Paula Mariela; Abele, Doris; Puntarulo, Susana

    2012-12-01

    Electron paramagnetic resonance uses the resonant microwave radiation absorption of paramagnetic substances to detect highly reactive and, therefore, short-lived oxygen and nitrogen centered radicals. Previously, steady state concentrations of nitric oxide, ascorbyl radical (A·) and the labile iron pool (LIP) were determined in digestive gland of freshly collected animals from the North Sea bivalve Mya arenaria. The application of a simple kinetic analysis of these data based on elemental reactions allowed us to estimate the steady state concentrations of superoxide anion, the rate of A· disappearance and the content of unsaturated lipids. This analysis applied to a marine invertebrate opens the possibility of a mechanistic understanding of the complexity of free radical and LIP interactions in a metabolically slow, cold water organism under unstressed conditions. This data can be further used as a basis to assess the cellular response to stress in a simple system as the bivalve M. arenaria that can then be compared to cells of higher organisms. PMID:22829190

  6. Richness, systematics, and distribution of molluscs associated with the macroalga Gigartina skottsbergii in the Strait of Magellan, Chile: A biogeographic affinity study

    Science.gov (United States)

    Rosenfeld, Sebastián; Aldea, Cristian; Mansilla, Andrés; Marambio, Johanna; Ojeda, Jaime

    2015-01-01

    Abstract Knowledge about the marine malacofauna in the Magellan Region has been gained from many scientific expeditions that were carried out during the 19th century. However, despite the information that exists about molluscs in the Magellan Region, there is a lack of studies about assemblages of molluscs co-occurring with macroalgae, especially commercially exploitable algae such as Gigartina skottsbergii, a species that currently represents the largest portion of carrageenans within the Chilean industry. The objective of this study is to inform about the richness, systematics, and distribution of the species of molluscs associated with natural beds in the Strait of Magellan. A total of 120 samples from quadrates of 0.25 m2 were obtained by SCUBA diving at two sites within the Strait of Magellan. Sampling occurred seasonally between autumn 2010 and summer 2011: 15 quadrates were collected at each site and season. A total of 852 individuals, corresponding to 42 species of molluscs belonging to Polyplacophora (9 species), Gastropoda (24), and Bivalvia (9), were identified. The species richness recorded represents a value above the average richness of those reported in studies carried out in the last 40 years in sublittoral bottoms of the Strait of Magellan. The biogeographic affinity indicates that the majority of those species (38%) present an endemic Magellanic distribution, while the rest have a wide distribution in the Magellanic-Pacific, Magellanic-Atlantic, and Magellanic-Southern Ocean. The molluscs from the Magellan Region serve as study models for biogeographic relationships that can explain long-reaching patterns and are meaningful in evaluating possible ecosystemic changes generated by natural causes or related to human activities. PMID:26448707

  7. Richness, systematics, and distribution of molluscs associated with the macroalga Gigartina skottsbergii in the Strait of Magellan, Chile: A biogeographic affinity study.

    Science.gov (United States)

    Rosenfeld, Sebastián; Aldea, Cristian; Mansilla, Andrés; Marambio, Johanna; Ojeda, Jaime

    2015-01-01

    Knowledge about the marine malacofauna in the Magellan Region has been gained from many scientific expeditions that were carried out during the 19th century. However, despite the information that exists about molluscs in the Magellan Region, there is a lack of studies about assemblages of molluscs co-occurring with macroalgae, especially commercially exploitable algae such as Gigartina skottsbergii, a species that currently represents the largest portion of carrageenans within the Chilean industry. The objective of this study is to inform about the richness, systematics, and distribution of the species of molluscs associated with natural beds in the Strait of Magellan. A total of 120 samples from quadrates of 0.25 m(2) were obtained by SCUBA diving at two sites within the Strait of Magellan. Sampling occurred seasonally between autumn 2010 and summer 2011: 15 quadrates were collected at each site and season. A total of 852 individuals, corresponding to 42 species of molluscs belonging to Polyplacophora (9 species), Gastropoda (24), and Bivalvia (9), were identified. The species richness recorded represents a value above the average richness of those reported in studies carried out in the last 40 years in sublittoral bottoms of the Strait of Magellan. The biogeographic affinity indicates that the majority of those species (38%) present an endemic Magellanic distribution, while the rest have a wide distribution in the Magellanic-Pacific, Magellanic-Atlantic, and Magellanic-Southern Ocean. The molluscs from the Magellan Region serve as study models for biogeographic relationships that can explain long-reaching patterns and are meaningful in evaluating possible ecosystemic changes generated by natural causes or related to human activities. PMID:26448707

  8. Mollusc life and death assemblages on a tropical rocky shore as proxies for the taphonomic loss in a fossil counterpart

    DEFF Research Database (Denmark)

    Sørensen, Anne Mehlin; Surlyk, Finn

    2013-01-01

    lower taxonomic agreement to the death assemblage than found in previous published studies. Rocky shore life and death assemblages thus appear to show lower taxonomic agreement compared to muddy or sandy shelf assemblages due to the mix after death with the sandy beach assemblage. A hypothetical fossil......Comparison of a modern rocky shore mollusc life assemblage from Thailand with the associated death assemblage, and interpretation of the fossilization potential of the latter, are used to investigate the fidelity in reconstruction of ancient analogues. The fauna from the death assemblage represents...... species from the rocky shore and the associated sandy pocket beaches, and only a few exotic species from other, completely different habitats are present. The environmental fidelity between the life and death assemblage is thus high, with the majority of species from the death assemblage representing the...

  9. [Reproductive cycle of the mangrove oyster Crassostrea rhizophorae (Bivalvia: Ostreidae) in Camamu Bay, Bahia, Brasil].

    Science.gov (United States)

    Lenz, Tiago; Boehs, Guisla

    2011-03-01

    The mangrove oyster Crassostrea rhizophorae is important fishery resource along the entire Brasilian coast with excellent potential for marine culture. The purpose of this paper was to examine the reproductive characteristics of the oyster of the Maraú river estuary in Camamu Bay, Bahia, Brasil. The samples were collected monthly, from September 2006 to August 2007, at two points (I and II) in Camamu Bay. At each site 20 oysters were collected for histological analysis, fixed in Davidson's solution, embedded in paraffin, dehydrated in an ethanol series, sectioned (7 microm thick) and stained with Harris hematoxylin and Eosin (HE). Additionally, 30 oysters were sampled, at each point, for a condition index analysis. The water temperature ranged from 23.5 degrees C to 30 degrees C and the salinity from 15 to 25 ups at Point I (Maraú) and from 25 to 35 at Point II (Tanque Island). The oyster's height ranged from 30 to 92 mm at Point I and from 27 to 102 mm at Point II, with an average of 49.0 mm +/- 9.1 (n = 230) and 49.9 mm +/- 9.9 (n = 237), respectively. Among the sampled oysters at Point I, 59.1% were females, 31.3% males, 1.3% hermaphrodites and 8.2% of the oysters of undetermined sex. At Point II, 66.2% were females, 30.4% males, 0.8% hermaphrodites and 2.5% (n = 237) of undetermined sex. The gonadic stage analysis indicated that the reproduction period of the C. rhizophorae in the Maraú Peninsula was continuous all year, without any regressive phase. The condition index (R) ranged from 8.0% to 17.7%. The peak periods of R coincided with the expressive oyster's percentage in the maturation and liberation gametic stages. The results of these findings will contribute information for the oyster spat collection and to the process installation of the oyster culture in Camamu Bay. PMID:21516642

  10. Cultivo de la ostra Crassostrea gigas (Thunberg, 1795 en un vivero artesanal, La arena, Casma

    Directory of Open Access Journals (Sweden)

    Paul Baltazar

    2014-06-01

    Full Text Available El presente trabajo describe la metodología empleada para el cultivo de la ostra del Pacífico Crassostrea gigas en un vivero artesanal, en el Centro Acuícola La Arena, Casma. Se utilizó reproductores en fase intermedia de madurez gonádica procedentes de líneas de cultivo del Centro Acuícola. El acondicionamiento se realizó en tanques de fibra de vidrio de 1000 L, con agua de mar sin filtrar a una temperatura de 27 ± 0,9 oC; adicionalmente se les alimentó con fécula de maíz y microalgas obtenidas en el lugar y cultivadas al aire libre. El desove se indujo para un grupo sólo por estimulación térmica (30 a 31 oC y para el otro se añadió además peróxido de hidrógeno, a lo cual se presentaron respuestas diferentes. A los 20 minutos después de la fertilización se observó, en el 100% de huevos fecundados, el cuerpo polar definido y a las 24 horas las larvas veliger. Las larvas alcanzaron el estado de pediveliger luego de 20 días de cultivo, con tallas promedios de 237 ± 10 µm. Para la fijación de las larvas se utilizó conchuela molida (300 µm, plástico negro lijado y valvas de ostras. A los 33 días se obtuvieron semillas con tallas medias de 1262 ± 204 µm las que fueron colocadas en pearl net para su desarrollo en el mar. A los 30 días de la siembra en el mar, la talla promedio de las postlarvas alcanzó los 13,4 ± 3,4 mm. El trabajo muestra las ventajas de la metodología descrita en la producción masiva de semillas en un vivero artesanal.

  11. Influence of incubation conditions on the anoxic survival of marine bivalves. Static and semi-static incubations

    NARCIS (Netherlands)

    De Zwaan, A.; Cattani, O.; Vitali, G.; Cortesi, P.

    2001-01-01

    In a comparative study of 4 bivalve species we show that the apparent widely different tolerances in survival time observed in a closed system filled with N-2-gassed seawater is mainly due to the experimental conditions. Both a high dose of cadmium and the antibiotic chloramphenicol increase surviva

  12. A striking parallel between cardiolipin fatty acid composition and phylogenetic belonging in marine bivalves: a possible adaptative evolution?

    Science.gov (United States)

    Kraffe, E; Grall, J; Le Duff, M; Soudant, P; Marty, Y

    2008-10-01

    Thirty-five species of marine mollusk bivalves were analyzed for their fatty acid (FA) composition of cardiolipin (Ptd(2)Gro). All species showed a Ptd(2)Gro with strong selectivity for only a few polyunsaturated fatty acids, but three characteristic FA profiles emerged, with clear parallels to bivalve phylogeny. A first group of 12 species belonging to the Eupteriomorphia subgroup (Filibranchia) was characterized by a Ptd(2)Gro almost exclusively composed of 22:6n-3, whereas in the four Filibranchia Pteriomorph species analyzed, this FA was combined with substantial proportions of 18:2n-6 and 18:3n-3. Finally, a third group of 20 species, all belonging to the Heterodonta subclass, possessed Ptd(2)Gro containing predominantly both 22:6n-3 and 20:5n-3. Polyunsaturated FA moieties and arrangements in the Ptd(2)Gro of some marine species investigated in other classes of the mollusk phylum (Gastropoda, Polyplacophora) were found to be different. The present results suggest that the specific Ptd(2)Gro FA compositions in bivalves are likely to be controlled and conserved in species of the same phylogenetic group. Functional significances of the evolution of this mitochondrial lipid structure in bivalves are discussed. PMID:18716818

  13. Relationship of Parasites and Pathologies to Contaminant Body Burden in Sentinel Bivalves: NOAA Status and Trends `Mussel Watch? Program

    OpenAIRE

    Kim, Yungkul; Powell, Eric N.; Wade, Terry L.; Presley, Bobby J.

    2008-01-01

    Relationship of Parasites and Pathologies to Contaminant Body Burden in Sentinel Bivalves: NOAA Status and Trends `Mussel Watch? Program correspondence: Corresponding author. (Kim, Yungkul) (Kim, Yungkul) Haskin Shellfish Research Laboratory Rutgers University 6959 Miller Ave Port Norris NJ 08349-3167 - (Kim, Yungkul) UNITED STATES (Kim, Yungkul) Haskin Shellfish Research Laboratory Rutgers University 6959 Miller ...

  14. Studies on the causes of mortality of the estuarine bivalve Macoma balthica under conditions of (near) anoxia

    NARCIS (Netherlands)

    De Zwaan, A.; Babarro, J.M.F.

    2001-01-01

    Survival of the bivalve Macoma balthica in (near) anoxic seawater was studied in a static system and a flow-through system and compared with emersed exposure to air and NZ In the static system, a decrease in pH and exponential accumulation of sulphide in the incubation medium were observed, indicati

  15. Aeromonas spp. isolated from oysters (Crassostrea rhizophorea from a natural oyster bed, Ceará, Brazil Aeromonas spp. isoladas de ostras (Crassostrea rhizophorea coletadas em um criadouro natural, Ceará, Brazil

    Directory of Open Access Journals (Sweden)

    Norma S. Evangelista-Barreto

    2006-06-01

    Full Text Available Between April and October 2002, thirty fortnightly collections of oysters (Crassostrea rhizophorea from a natural oyster bed at the Cocó River estuary in the Sabiaguaba region (Fortaleza, Ceará, Brazil were carried out, aiming to isolate Aeromonas spp. strains. Oyster samples were submitted to the direct plating (DP and the presence/absence (P/A methods. Aeromonas were identified in 15 (50% samples analyzed by the DP method and in 13 (43% analyzed by the P/A method. A. caviae, A. eucrenophila, A. media, A. sobria, A. trota, A. veronii bv. sobria, A. veronii bv. veronii and Aeromonas sp. were isolated. The predominant species was A. veronii (both biovars, which was identified in 13 (43% samples, followed by A. media in 11 (37% and A. caviae in seven (23%. From the 59 strains identified, 28 (48% presented resistance to at least one of the eight antibiotics tested.Foram realizadas 30 coletas quinzenais, entre abril e outubro de 2002, de ostras (Crassostrea rhizophorea de um criadouro natural, no estuário do rio Cocó (Fortaleza/Ceará/Brasil, objetivando-se isolar cepas de Aeromonas spp. As amostras de ostras foram submetidas aos métodos de plaqueamento direto (PD e presença/ausência (P/A. Foram identificadas Aeromonas em 15 (50% amostras analisadas pelo método PD e em 13 (43% pelo método P/A. Foram isoladas: A. caviae, A. eucrenophila, A. media, A. sobria, A. trota, A. veronii bv. sobria, A. veronii bv. veronii e Aeromonas sp. A espécie predominate foi A. veronii (ambos biovars, identificada em 13 (43% amostras, seguida de A. media em 11 (37% e A. caviae em 7 (23%. Das 59 cepas identificadas, 28 (48% apresentaram resistência a pelo menos um, dos oitos antibióticos testados.

  16. Short and long term consequences of larval stage exposure to constantly and ephemerally elevated carbon dioxide for marine bivalve populations

    Directory of Open Access Journals (Sweden)

    C. J. Gobler

    2012-11-01

    Full Text Available While larval bivalves are highly sensitive to ocean acidification, the basis for this sensitivity and the longer term implications of this sensitivity are unclear. Experiments were performed to assess the short term (days and long term (months consequences of larval stage exposure to varying CO2 concentrations for calcifying bivalves. Higher CO2 concentrations depressed both calcification rates assessed using 45Ca uptake and RNA:DNA ratios in Mercenaria mercenaria and Argopecten irradians larvae with RNA:DNA ratios being highly correlated with larval growth rates r2 > 0.9. These findings suggested that high CO2 has a cascading negative physiological impact on bivalve larvae stemming in part from lower calcification rates. Exposure to elevated CO2 during the first four days of larval development significantly depressed A. irradians larval survival rates, while a 10 day exposure later in larval development did not, demonstrating the extreme CO2-sensitivity of bivalve larvae during first days of development. Short- (weeks and long-term (10 month experiments revealed that individuals surviving exposure to high CO2 during larval development grew faster when exposed to normal CO2 as juveniles compared to individuals reared under ambient CO2 as larvae. These increased growth rates could not, however, overcome size differences established during larval development, as size deficits of individuals exposed to even moderate levels of CO2 as larvae were evident even after 10 months of growth under normal CO2 concentrations. This `legacy effect' emphasizes the central role larval stage CO2 exposure can play in shaping the success of modern day bivalve populations.

  17. Influences of organic matter and calcification rate on trace elements in aragonitic estuarine bivalve shells

    Science.gov (United States)

    Takesue, Renee K.; Bacon, Charles R.; Thompson, Janet K.

    2008-11-01

    A suite of elements (B, Na, Mg, S, K, Ca, V, Mn, Cr, Sr, and Ba) was measured in aragonitic shells of the estuarine bivalve Corbula amurensis, the Asian clam, using the Sensitive High-Resolution Ion MicroProbe with Reverse Geometry (SHRIMP RG). Our initial intent was to explore potential geochemical proxy relationships between shell chemistry and salinity (freshwater inflow) in northern San Francisco Bay (SFB). In the course of this study we observed variations in shell trace element to calcium ([M]/Ca) ratios that could only be attributed to internal biological processes. This paper discusses the nature and sources of internal trace element variability in C. amurensis shells related to the shell organic fraction and shell calcification rates. The average organic content of whole C. amurensis shells is 19%. After treating whole powdered shells with an oxidative cleaning procedure to remove organic matter, shells contained on average 33% less total Mg and 78% less total Mn. Within our analytical uncertainty, Sr and Ba contents were unchanged by the removal of organic matter. These results show that aragonitic C. amurensis shells have a large component of non-lattice-bound Mg and Mn that probably contribute to the dissimilarity of [M]/Ca profiles among five same-sized shells. Non-lattice-bound trace elements could complicate the development and application of geochemical proxy relationships in bivalve shells. Because B, Ba and Sr occur exclusively in shell aragonite, they are good candidates for external proxy relationships. [M]/Ca ratios were significantly different in prismatic and nacreous aragonite and in two valves of the same shell that had different crystal growth rates. Some part of these differences can be attributed to non-lattice-bound trace elements associated with the organic fraction. The differences in [M]/Ca ratios were also consistent with the calcification rate-dependent ion transport model developed by Carré et al. [Carré M., Bentaleb I

  18. A Large Metabolic Carbon Ccontribution to the δ13C Record in Marine Aragonitic Bivalve Shells

    Science.gov (United States)

    Gillikin, D. P.; Lorrain, A.; Dehairs, F.

    2006-12-01

    The stable carbon isotopic signature archived in bivalve shells was originally thought to record the δ13C of seawater dissolved inorganic carbon (δ13C-DIC). However, more recent studies have shown that the incorporation of isotopically light metabolic carbon (M) significantly affects the δ13C signal recorded in biogenic carbonates. To assess the M contribution to Mercenaria mercenaria shells collected in North Carolina, USA, we sampled seawater δ13C-DIC, tissue, hemolymph and shell δ13C. We found up to a 4‰ decrease through ontogeny in shell δ13C in a 23 year old individual. There was no correlation between shell height or age and tissue δ13C. Thus, the ontogenic decrease observed in the shell δ13C could not be attributed to changes in food sources as the animal ages leading to more negative metabolic CO2, since this would require a negative relationship between tissue δ13C and shell height. Hemolymph δ13C, on the other hand, did exhibit a negative relationship with height, but the δ13C values were more positive than expected, indicating that hemolymph may not be a good proxy of extrapallial fluid δ13C. Nevertheless, the hemolymph data indicate that respired CO2 does influence the δ13C of internal fluids and that the amount of respired CO2 is related to the age of the bivalve. The percent metabolic C incorporated into the shell (%M) was significantly higher (up to 37%) than has been found in other bivalve shells, which usually contain less than 10 %M. Attempts to use shell biometrics to predict %M could not explain more than ~60% of the observed variability. Moreover, there were large differences in the %M between different sites. Thus, the metabolic effect on shell δ13C cannot easily be accounted for to allow reliable δ13C-DIC reconstructions. However, there does seem to be a common effect of size, as all sites had indistinguishable slopes between the %M and shell height (+0.19% per mm of shell height).

  19. Boccardia sp. (Polychaete: Spionidae presence in Crassostrea gigas [Thunberg, 1873] oysters reared in the mid coast of the Mexican Pacific

    Directory of Open Access Journals (Sweden)

    M. C. Gallo-García

    2005-01-01

    Full Text Available Desde 1997 se han realizado varios estudios acerca del cultivo del ostión del Pacífico, Crassostrea gigas, en la Laguna de Barra de Navidad (Jalisco, México. La presencia de ampollas de lodo en las valvas internas del ostión causadas por gusanos barrenadores de la concha, ha representado uno de los principales problemas en el cultivo. Boccardia sp. (Polychaete: Spionidae fue identificado de una muestra de 60 ostiones estudiados. A pesar del efecto de este gusano en el cultivo de ostión, se carece de información sobre su impacto en la industria ostrícola mexicana. El presente trabajo representa un primer reporte sobre la ocurrencia de este poliqueto en los cultivos de C. gigas que se localizan en la costa media del Pacífico mexicano

  20. Transmission of the haplosporidian parasite MSX Haplosporidium nelsoni to the eastern oyster Crassostrea virginica in an upweller system.

    Science.gov (United States)

    Sunila, I; Karolus, J; Lang, E P; Mroczka, M E; Volk, J

    2000-08-31

    The haplosporidian oyster parasite MSX (Multinucleated Sphere X) Haplosporidium nelsoni was transmitted to eastern oysters Crassostrea virginica. Hatchery-raised, MSX-free juvenile oysters were placed in upweller tanks. Water to the tanks was filtered through a screen with 1 mm2 openings and originated from the water column overlaying naturally infected oysters beds (MSX prevalence 17 to 57%). MSX was diagnosed by histopathological analysis. MSX-disease (57% prevalence) with increased mortality (19%) was observed 11 wk after the beginning of the exposure and mortality of 80% after 16 wk. The study demonstrates transmission of MSX via water-borne infectious agents capable of passing through a 1 mm filter. PMID:11023255