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the role of phytoplankton in the modulation of dissolved and oyster cadmium concentrations in deep bay, british columbia, canada.we previously identified dissolved cadmium (cd(diss)) as the main source of this metal in cultured pacific oysters, crassostrea gigas, in deep bay, british columbia, canada (lekhi et al., 2008). total suspended particulate cd (cd(part)) was not found to be a significant source of oyster cd (cd(oys)), with cd(part) >20 μm negatively correlated with cd(oys) concentration. high phytoplankton abundance in spring and summer was hypothesized to reduce cd(oys) indirectly by drawing down cd(diss) and in ...201121820696
whole transcriptome profiling of successful immune response to vibrio infections in the oyster crassostrea gigas by digital gene expression analysis.the cultivated pacific oyster crassostrea gigas has suffered for decades large scale summer mortality phenomenon resulting from the interaction between the environment parameters, the oyster physiological and/or genetic status and the presence of pathogenic microorganisms including vibrio species. to obtain a general picture of the molecular mechanisms implicated in c. gigas immune responsiveness to circumvent vibrio infections, we have developed the first deep sequencing study of the transcript ...201121829707
microarray analysis highlights immune response of pacific oysters as a determinant of resistance to summer mortality.summer mortality of crassostrea gigas is the result of a complex interaction between oysters, their environment, and pathogens. a high heritability was estimated for resistance to summer mortality, which provided an opportunity to develop lines of oysters that were resistant (r) or susceptible (s) to summer mortality. previous genome-wide expression profiling study of r and s oyster gonads highlighted reproduction and antioxidant defense as constitutive pathways that operate differentially betwe ...201221845383
effect of carbonate chemistry alteration on the early embryonic development of the pacific oyster (crassostrea gigas).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 ...201121860666
long-term records of cadmium and silver contamination in sediments and oysters from the gironde fluvial-estuarine continuum - evidence of changing silver sources.the gironde fluvial estuarine system is impacted by historic metal pollution (e.g. cd, zn, hg) and oysters (crassostrea gigas) from the estuary mouth have shown extremely high cd concentrations for decades. based on recent work (chiffoleau et al., 2005) revealing anomalously high ag concentrations (up to 65 mg kg(-1); dry weight) in gironde oysters, we compared long-term (~1955-2001) records of ag and cd concentrations in reservoir sediment with the respective concentrations in oysters collected ...201121868056
shell thickening and chambering in the oyster crassostrea gigas: natural and anthropogenic influence of tributyltin contamination.abnormal thickening and chambering in crassostrea gigas oysters have been adopted for many years as bioindicators of available tributyltin (tbt) in coastal waters. nevertheless, since natural causes can also induce the formation of multiple chambers, a field study and laboratory experimentation has been conducted with 72 examples of c. gigas in successive culture media. this work has enabled differences to be established between natural fine sediment-induced characteristics and the influence of ...201121877539
effect of acclimatization on hemocyte functional characteristics of the pacific oyster (crassostrea gigas) and carpet shell clam (ruditapes decussatus).most experimental procedures on molluscs are done after acclimatization of wild animals to lab conditions. similarly, short-term acclimation is often unavoidable in a field survey when biological analysis cannot be done within the day of sample collection. however, acclimatization can affect the general physiological condition and particularly the immune cell responses of molluscs. our aim was to study the changes in the hemocyte characteristics of the pacific oyster crassostrea gigas and the ca ...201121906683
genetic mapping and qtl analysis of growth-related traits in the pacific oyster.the pacific oyster (crassostrea gigas) is one of the most important oysters cultured worldwide. to analyze the oyster genome and dissect growth-related traits, we constructed a sex-averaged linkage map by combining 64 genomic simple sequence repeats, 42 expressed sequence tag-derived ssrs, and 320 amplified fragment length polymorphism markers in an f(1) full-sib family. a total of 426 markers were assigned to 11 linkage groups, spanning 558.2 cm with an average interval of 1.3 cm and 94.7% of g ...201221932055
quantifying ostreid herpesvirus (oshv-1) genome copies and expression during transmission.understanding the pathogenic potential of a new pathogen strain or a known pathogen in a new locale is crucial for management of disease in both wild and farmed animals. the ostreid herpesvirus-1 (oshv-1), a known pathogen of early-life-stage pacific oysters, crassostrea gigas, has been associated with mortalities of juvenile oysters in many locations around the world including tomales bay, california. in two trials, the california oshv-1 strain was transmitted from infected juvenile c. gigas to ...201121935610
quantitative trait locus analysis of stage-specific inbreeding depression in the pacific oyster crassostrea gigas.inbreeding depression and genetic load have been widely observed, but their genetic basis and effects on fitness during the life cycle remain poorly understood, especially for marine animals with high fecundity and high, early mortality (type-iii survivorship). a high load of recessive mutations was previously inferred for the pacific oyster crassostrea gigas, from massive distortions of zygotic, marker segregation ratios in f(2) families. however, the number, genomic location, and stage-specifi ...201121940682
cloning and localization of mcdef, a defensin from manila clams (ruditapes philippinarum).a defensin-like peptide was previously detected in hemocytes of manila clams (ruditapes philippinarum). in the current study, we cloned and characterized this defensin, designated mcdef. cloning produced a full-length gene sequence of 201 bp predicted to encode a 66-amino-acid precursor protein maturing to a 44-amino-acid residue. amino acid sequence analysis showed that mcdef is similar to defensins from marine mollusks and ticks. phylogenetic analysis suggested that mcdef is closely related to ...201221945146
development of a pacific oyster (crassostrea gigas) 31,918-feature microarray: identification of reference genes and tissue-enriched expression patterns.research using the pacific oyster crassostrea gigas as a model organism has experienced rapid growth in recent years due to the development of high-throughput molecular technologies. as many as 56,268 est sequences have been sequenced to date, representing a genome-wide resource that can be used for transcriptomic investigations.201121951653
big defensins, a diverse family of antimicrobial peptides that follows different patterns of expression in hemocytes of the oyster crassostrea gigas.big defensin is an antimicrobial peptide composed of a highly hydrophobic n-terminal region and a cationic c-terminal region containing six cysteine residues involved in three internal disulfide bridges. while big defensin sequences have been reported in various mollusk species, few studies have been devoted to their sequence diversity, gene organization and their expression in response to microbial infections.201121980497
quantitative determination of marine lipophilic toxins in mussels, oysters and cockles using liquid chromatography-mass spectrometry: inter-laboratory validation study.thirteen laboratories participated in an inter-laboratory study to evaluate the method performance characteristics of a liquid chromatography-tandem mass spectrometric method (lc-ms/ms) for marine lipophilic shellfish toxins. method performance characteristics were evaluated for mussel (mytilus edulis), oyster (crassostrea gigas) and cockle (cerastoderma edule) matrices. the specific toxin analogues tested included okadaic acid (oa), dinophysistoxins-1 and -2 (dtx1, -2), azaspiracids-1, -2 and - ...201121995816
predictive models for the effect of storage temperature on vibrio parahaemolyticus viability and counts of total viable bacteria in pacific oysters (crassostrea gigas).vibrio parahaemolyticus is an indigenous bacterium of marine environments. it accumulates in oysters and may reach levels that cause human illness when postharvest temperatures are not properly controlled and oysters are consumed raw or undercooked. predictive models were produced by injecting pacific oysters (crassostrea gigas) with a cocktail of v. parahaemolyticus strains, measuring viability rates at storage temperatures from 3.6 to 30.4°c, and fitting the data to a model to obtain parameter ...201122003032
effects of low-dose exposure to pesticide mixture on physiological responses of the pacific oyster, crassostrea gigas.this study investigated the effects on the physiology of pacific oyster, crassostrea gigas, of a mixture of pesticides containing 0.8 μg l(-1) alachlor, 0.6 μg l(-1) metolachlor, 0.7 μg l(-1) atrazine, 0.6 μg l(-1) terbuthylazine, 0.5 μg l(-1) diuron, 0.6 μg l(-1) fosetyl aluminum, 0.05 μg l(-1) carbaryl, and 0.7 μg l(-1) glyphosate for a total concentration of 4.55 μg l(-1) . the total nominal concentration of pesticides mixture corresponds to the pesticide concentrations in the shellfi ...201122012874
comparative ultrastructural study of spermatozoa in some oyster species from the asian-pacific coast.sperm organization in the oysters crassostrea gigas, crassostrea nippona, crassostrea cf. rivularis and saccostrea cf. mordax inhabiting asian pacific coast was studied. the spermatozoa of all studied species had a number of common morphological characters such as a cup-like acrosome with heterogeneous matrix on its top, an axial rod in the subacrosomal space, a barrel-shaped nucleus, four mitochondria in the midpiece, pericentriolar complexes, and a 9+2-organized flagellum. the spermatozoa of c ...201222019496
antioxidant deficit in gills of pacific oyster (crassostrea gigas) exposed to chlorodinitrobenzene increases menadione toxicity.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 gl ...201222036013
comparative study of various immune parameters in three bivalve species during a natural bloom of dinophysis acuminata in santa catarina island, brazil.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 apop ...201022069632
Non-specific defensive factors of the Pacific oyster Crassostrea gigas against infection with Marteilioides chungmuensis: a flow-cytometric study.In order to assess changes in the activity of immunecompetency present in Crassostrea gigas infected with Marteilioides chungmuensis (Protozoa), the total hemocyte counts (THC), hemocyte populations, hemocyte viability, and phagocytosis rate were measured in oysters using flow cytometry. THC were increased significantly in oysters infected with M. chungmuensis relative to the healthy appearing oysters (HAO) (P<0.05). Among the total hemocyte composition, granulocyte levels were significantly inc ...201122072822
in vivo rna interference of a gonad-specific transforming growth factor-β in the pacific oyster crassostrea gigas.we investigated the role of oyster gonadal tgfβ (og-tgfβ) in the reproduction of crassostrea gigas, using an in vivo rna interference approach. we designed double-stranded rna targeting og-tgfβ, 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-tgfβ dsrna into the gonad led to knock-down phenotypes for both sexes, with significant reduction (77.52% relative to controls) of the gonad area, lowered ...201222147255
characterisation and genetic polymorphism of metallothionein gene cgmt4 in experimental families of pacific oyster crassostrea gigas displaying summer mortality.summer mortality events have been observed in pacific oyster crassostrea gigas for several decades. this paper examines the selective pressure exerted by summer mortality on the polymorphism of a newly identified oyster metallothionein gene. cgmt4 cdna and genomic sequences were obtained. cgmt4 was studied in two generations of oysters reared in three sites on the french atlantic coast, using single strand conformation polymorphism analysis. four alleles were detected. individuals carrying genot ...201222149898
shell disturbances and butyltins burden in commercial bivalves collected from the bizerta lagoon (northern tunisia).shell disturbances and soft tissues butyltin burden were investigated in commercial bivalves lithophaga lithophaga, mytilus galloprovincialis, solen marginatus and crassostrea gigas from the bizerta lagoon. shell disturbances were found in all bivalves, being scarce in s. marginatus. in the internal valve of l. lithophaga, burrowing annelids and sipunculids living inside galleries were observed, while in the external valve, brown-blackish or white stains were found. in m. galloprovincialis, a ye ...201222170157
a crucial role in fertility for the oyster angiotensin-converting enzyme orthologue cgace.angiotensin-converting enzyme (ace) is a highly conserved metallopeptidase. in mammals, the somatic isoform governs blood pressure whereas the germinal isoform (tace) is required for fertility. in ecdysozoans, ace-like enzymes are implicated in reproduction. despite ace orthologues being present from bacteria to humans, their function(s) remain(s) unknown in distant organisms such as lophotrochozoans. in silico analysis of an oyster (crassostrea gigas) est library suggested the presence of an ac ...201122174750
impact of a sacrificial anode as assessed by zinc accumulation in different organs of the oyster crassostrea gigas: results from long- and short-term laboratory tests.sacrificial anodes made of zinc are currently used in marine environments to mitigate marine corrosion as part of cp systems of immerged metallic structures. the aim of this work was to study zinc bioconcentration in the oyster crassostrea gigas by performing two in vivo tests during different time periods and at different zinc concentrations. the first test was conducted during a period of 10 weeks at a concentration of 0.53 ± 0.04 mg zn l(-1) to simulate long-term exposure, and a second test w ...201122183875
geographical and annual variation in lipophilic shellfish toxins from oysters and mussels along the south coast of korea.to better understand critical aspects of diarrhetic shellfish poisoning (dsp) occurrence in a chief producing region of bivalves in korea, the geographical and annual variation of dsp toxins and other lipophilic toxins in mussels (mytilus galloprovincialis) and oysters (crassostrea gigas) were investigated by liquid chromatography-tandem mass spectrometry in an area on the south coast of korea from 2007 to 2009. the total lipophilic shellfish toxin (lst) levels in bivalves showed geographical an ...201122186054
a novel silk-like shell matrix gene is expressed in the mantle edge of the pacific oyster prior to shell regeneration.during shell formation, little is known about the functions of organic matrices, especially about the biomineralization of shell prismatic layer. we identified a novel gene, shelk2, from the pacific oyster presumed to be involved in the shell biosynthesis. the pacific oyster has multiple copies of shelk2. shelk2 mrna is specifically expressed on the mantle edge and is induced during shell regeneration, thereby suggesting that shelk2 is involved in shell biosynthesis. to our surprise, the databas ...201222197657
identification of ras, pten and p70s6k homologs in the pacific oyster crassostrea gigas and diet control of insulin pathway.insulin pathways were demonstrated from invertebrates to vertebrates to be involved in the regulation of numerous processes including storage metabolism and reproduction. in addition, insulin system may integrate variations of environmental conditions like dietary restrictions. in the pacific oyster crassostrea gigas, reproductive and storage compartments are closely intricated in the gonadal area and their respective development was found to be dependant of trophic conditions. for these reasons ...201222202600
responses of pacific oyster crassostrea gigas populations to abiotic stress in environmentally contrasted estuaries along the atlantic coast of france.genetic and ecophysiological responses of oyster, crassostrea gigas, populations to environmental stress were investigated in three highly contaminated french estuaries (the gironde, loire and vilaine) and compared to a control, the belon estuary. a strong response in both metallothionein cgmt4 mrna expression, as determined by semi-quantitative rt-pcr, and amount of protein, as determined by elisa tests, was demonstrated in estuarine populations subjected to differential contamination, with an ...201222204990
isolation and characterization of a phenolic antioxidant from the pacific oyster (crassostrea gigas).using an oxygen radical absorbance capacity (orac) assay, antioxidant activity was detected in the ethanol extract of the pacific oyster, which was purified by sequential extraction with organic solvents. the ethyl acetate fraction showed the strongest antioxidant activity and was further purified, yielding a single compound [as assessed by thin-layer chromatography (tlc) and reverse-phase high-performance liquid chromatography (hplc)]. this compound was identified as 3,5-dihydroxy-4-methoxybenz ...201222224848
characterizing short read sequencing for gene discovery and rna-seq analysis in crassostrea gigas.advances in dna sequencing technology have provided opportunities to produce new transcriptomic resources for species that lack completely sequenced genomes. however, there are limited examples that rely solely on ultra-short read sequencing technologies (e.g. solexa, solid) for transcript discovery and gene expression analysis (i.e. rna-seq). here we use solid sequencing to examine gene expression patterns in pacific oyster (crassostrea gigas) populations exposed to varying degrees of anthropog ...201222244882
comparison of haemocytic parameters among flat oyster ostrea edulis stocks with different susceptibility to bonamiosis and the pacific oyster crassostrea gigas.farming of the flat oyster ostrea edulis in europe is severely constrained by the protozoan bonamia ostreae. the introduction of the resistant species crassostrea gigas has been a relief for the farmers, while the pilot programmes to select o. edulis strains resistant to bonamiosis performed in various countries can be seen as a promising strategy to minimise the effects of bonamiosis. however, the physiological bases of this differential susceptibility remain unknown. a search for an explanatio ...201222245470
toxicity evaluation of diethylene glycol and its combined effects with produced waters of off-shore gas platforms in the adriatic sea (italy): bioassays with marine/estuarine species.diethylene glycol (deg) is commonly used to dehydrate natural gas in off-shore extraction plants and to prevent formation of gas hydrates. it may be released into the sea accidentally or in discharged produced waters (pws). pws samples from off-shore gas platforms in the adriatic sea (italy) have been used in this study. the objectives of the study were: a) to evaluate the toxicity of deg for marine organisms; b) to evaluate if a high deg content in pws may alter their toxicity; c) to verify whe ...201222245535
characterization of gnrh-related peptides from the pacific oyster crassostrea gigas.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 ...201222306476
assessing a bioremediation strategy in a shallow coastal system affected by a fish farm culture--application of gis and shellfish dynamic models in the rio san pedro, sw spain.an integrated multi-trophic aquaculture assessment for pacific oyster (crassostrea gigas) aquaculture as a bioremediation strategy in areas impacted by fish farm effluents in rio san pedro was assessed by combining geographic information system with carrying capacity models. sites of 0.44 km(2) were evaluated considering constraints; physical factors, growth and survival factors, environmental quality factors, water and sediment quality criteria, factor suitability ranges, and multi-criteria eva ...201222310375
the depuration dynamics of oysters (crassostrea gigas) artificially contaminated with hepatitis a virus and human adenovirus.within the country of brazil, santa catarina is a major shellfish producer. detection of viral contamination is an important step to ensure production quality and consumer safety during this process. in this study, we used a depuration system and ultraviolet (uv) disinfection to eliminate viral pathogens from artificially infected oysters and analysed the results. specifically, the oysters were contaminated with hepatitis a virus (hav) or human adenovirus type 5 (hadv5). after viral infection, t ...201222310530
mollusc gonadotropin-releasing hormone directly regulates gonadal functions: a primitive endocrine system controlling reproduction.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 crassost ...201222326349
expression, tissue localization and synergy of antimicrobial peptides and proteins in the immune response of the oyster crassostrea gigas.diverse families of antimicrobial peptides and proteins have been described in oysters. we investigated here how antimicrobials are involved in the immune response against a pathogenic strain of vibrio splendidus. oyster antimicrobials were shown to display a wide variety of expression profiles in hemocyte populations and tissues. oyster defensins are constitutively expressed in specific tissues such as mantle (cg-defm) or hemocytes (cg-defhs), while cg-bpi is inducible and cg-prp appears down-r ...201222327168
bioaccumulation and metabolisation of (14)c-pyrene by the pacific oyster crassostrea gigas exposed via seawater.the first objective of this study was to determine the bioaccumulation kinetics of pyrene in the soft tissues of crassostrea gigas (mantle, muscle, gills, digestive gland, and the remaining soft tissues). as bivalves can biotransform hydrocarbons in more polar compounds (metabolites) that are more easily excreted, the second objective was to investigate the oyster capacity to metabolize pyrene into its metabolite, the 1-hydroxypyrene. to these ends, oysters were exposed 24 h to waterborne (14)c- ...201222342284
investigation of mortality in pacific oysters associated with ostreid herpesvirus-1 μvar in the republic of ireland in 2009.high levels of mortality in pacific oysters crassostrea gigas in the republic of ireland were recorded during the summer of 2009. the new variant of ostreid herpes 1 (oshv-1 μvar) which first emerged in france in 2008 was identified from affected stocks. retrospective data was collected from 70 oyster farmers through an interviewer-administered questionnaire to investigate the distribution and determinants of the mortality. based on farmer recall, data were recorded at the batch level for cumula ...201222398251
detection of early effects of a single herbicide (diuron) and a mix of herbicides and pharmaceuticals (diuron, isoproturon, ibuprofen) on immunological parameters of pacific oyster (crassostrea gigas) spat.in the context of massive summer mortality events of the pacific oyster crassostrea gigas, the aim of this study was to investigate the early effects on genes, enzymes and haemocyte parameters implicated in immune defence mechanisms in c. gigas oysters exposed to a potentially hostile environment, i.e. to an herbicide alone or within a mixture. following 2 h of exposure to the herbicide diuron at 1 μg l(-1), the repression of different genes implicated in immune defence mechanisms in the haemocy ...201222405722
molecular analysis of the bacterial communities in the live pacific oyster (crassostrea gigas) and the influence of postharvest temperature on its structure.to evaluate the effect of postharvest temperature on bacterial communities in live pacific oysters (crassostrea gigas) using nonculture-based methods.201222429335
molecular analysis of bacterial microbiota associated with oysters (crassostrea gigas and crassostrea corteziensis) in different growth phases at two cultivation sites.microbiota presumably plays an essential role in inhibiting pathogen colonization and in the maintenance of health in oysters, but limited data exist concerning their different growth phases and conditions. we analyzed the bacterial microbiota composition of two commercial oysters: crassostrea gigas and crassostrea corteziensis. differences in microbiota were assayed in three growth phases: post-larvae at the hatchery, juvenile, and adult at two grow-out cultivation sites. variations in the micr ...201222450510
influence of crassostrea gigas (thunberg) sexual maturation stage and ploidy on uptake of paralytic phycotoxins.the purpose of this study was to assess paralytic phycotoxin uptake in diploid and triploid oysters at two stages of their sexual cycle corresponding to their status in early summer (june) and winter (november). samples of diploid and triploid oysters were exposed to a toxic culture of alexandrium minutum for 4 days in each season. no significant differences in filtration or clearance rates were observed during either november or june experiments. when diploid oysters were at resting stage (nove ...201222465018
live algae as a vector candidate for hydrophobic polychlorinated biphenyls translocation to bivalve filter feeders for laboratory toxicity test.live algae carrying hydrophobic xenobiotics can be an effective vector candidate for the chemical translocation to filter feeders in the laboratory toxicity test, but information on their application is lacking. time-course uptake and elimination of polychlorinated biphenyls (pcbs) (0, 50, 100, and 500 ng g(-1) by two key algal foods, isochrysis galbana and tetraselmis suecica, were measured. both of the algae achieved maximum concentration in an hourafter pcbs exposure regardless the chemical c ...201122471217
reductions of vibrio parahaemolyticus in pacific oysters (crassostrea gigas) by depuration at various temperatures.consumption of raw oysters has been linked to several outbreaks of vibrio parahaemolyticus infection in the united states. this study investigated effects of ice storage and uv-sterilized seawater depuration at various temperatures on reducing v. parahaemolyticus in oysters. raw pacific oysters (crassostrea gigas) were inoculated with a mixed culture of five clinical strains of v. parahaemolyticus (10290, 10292, 10293, be 98-2029 and 027-1c1) at levels of 10⁴⁻⁶ mpn/g. inoculated oysters were eit ...201222475942
comparative bioaccumulation of trace metals using six filter feeder organisms in a coastal lagoon ecosystem (of the central-east gulf of california).the tobari lagoon, located in the central-east coast of the gulf of california, receives effluents from the yaqui valley, one of the most extensive agricultural areas of méxico. the tobari lagoon also receives effluents from nearby shrimp farms and untreated municipal sewage. surface sediment samples and six different species of filter feeders (crassostrea corteziensis, crassostrea gigas, chione gnidia, anadara tuberculosa, chione fluctifraga, and fistulobalanus dentivarians) were collected duri ...201322527455
crassostrea gigas oysters as a shrimp farm bioindicator of white spot syndrome virus.this study explored whether crassostrea gigas oysters can be used as a bioindicator of white spot syndrome virus (wssv) in shrimp farm water canals. bioassays showed that c. gigas can accumulate wssv in their gills and digestive glands but do not become infected, either by exposure to seawater containing wssv or by cohabitation with infected shrimp. the use of a wssv nested pcr to screen oysters placed in water canals at the entry of a shrimp farm allowed wssv to be detected 16 d prior to the di ...201222535870
setting tools for the early assessment of the quality of thawed pacific oyster (crassostrea gigas) d-larvae.parameters used to assess the survival of larvae after cryopreservation generally misestimate the damages that prevent larval development. the objectives of the present study were to 1) define the reliability of the survival rate, assessed at 2 and 7 days post fertilization, to estimate pacific oyster larval quality after thawing, and 2) select complementary tools allowing an early and reliable estimation of their quality. oyster larvae were reared for 25 h after fertilization at 19 °c and cryop ...201222538008
influence of oyster culture on biogeochemistry and bacterial community structure at the sediment-water interface.bacterial community structure and some biogeochemical parameters were studied in the sediment of two pacific oyster farming sites, aber benoît (ab) and rivière d'auray (ra) in brittany (france), to examine the ecological impact of oysters and to evaluate the emission of sulfide and ammonia from sediment. at ab, the organic matter accumulated in the sediment beneath the oyster tables was rapidly mineralized, with strong fluxes of ammonia and sulfide that reached 1014 and 215 μmol m(-2) h(-1), res ...201222571367
expression of a natural antisense transcript of cg-foxl2 during the gonadic differentiation of the oyster crassostrea gigas: first demonstration in the gonads of a lophotrochozoa species.in the oyster crassostrea gigas, a successive hermaphrodite, cg-foxl2, an ortholog of foxl2, is suspected to be involved in vitellogenesis or female sex determination. the existence of a natural antisense transcript (nat) of this factor has been suspected in gonads but needs to be confirmed to better understand the early events of the gonadic differentiation. the occurrence of this nat was studied by orientation-specific rt-pcr. the nat and its mrna expressions were investigated during the devel ...201222572405
starch supplementation modulates amylase enzymatic properties and amylase b mrna level in the digestive gland of the pacific oyster crassostrea gigas.in the oyster crassostrea gigas consumption-related traits, amylase properties and growth were found to be linked through genotypes that differed for polymorphism in the two amylase genes amya and amyb. modulation of amya mrna level had already been observed in response to food availability, whereas the functional role of amyb was still unknown. to improve knowledge about the regulation of amylase expression in c. gigas and the respective roles of the two genes, we made an assay of amylase expre ...201222580267
gametogenesis in the pacific oyster crassostrea gigas: a microarrays-based analysis identifies sex and stage specific genes.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 transcriptome. the ...201222590533
cellular and transcriptional responses of crassostrea gigas hemocytes exposed in vitro to brevetoxin (pbtx-2).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 1 ...201222611355
effects of heavy metals on the expression of a zinc-inducible metallothionein-iii gene and antioxidant enzyme activities in crassostrea gigas.sequestration by metallothioneins and antioxidant defense are two kinds of important defense mechanisms employed by mollusks to minimize adverse effects caused by heavy metal contaminants in marine environment. in the present study, a novel metallothionein gene, cgmt-iii, was cloned from crassostrea gigas, consisting of eighteen conserved cysteine residues and encoding a mt iii-like protein with two tandem β domains. the expression level of cgmt-iii transcript induced by zinc was much higher tha ...201222614035
[mycobiota of giant oyster, crassostrea gigas (thunberg, 1787) (bivalvia), from the peter the great bay, sea of japan]. 201222629688
identification of differentially expressed proteins involved in the early larval development of the pacific oyster crassostrea gigas.the trochophore and d-veliger are two pivotal but distinct developmental stages in bivalve larval development. complex morphological and physiological processes are involved in the transition between these stages, yet the underlying molecular mechanisms remain largely elusive. in this study, a comparative proteomic analysis was conducted to identify the proteins related to early larval development of the pacific oyster crassostrea gigas. fifty proteins showing different levels of expression were ...201222634042
a study of diagnostic methods for marteilioides chungmuensis infections in the pacific oyster crassostrea gigas.the eggs of the pacific oyster, crassostraea gigas, become infertile when infected by the parasite marteilioides chungmuensis. histologically, m. chungmuensis infects the oyster oocyte cytoplasm, and the ovaries take on a "lumpy" appearance once infected, which lowers commercial value of the oyster. this has a negative economic impact on oyster farms in south korea and japan. in this study, we compared traditional diagnostic methods (histology) with two molecular-based methods (polymerase chain ...201222634519
the chronic toxicity of molybdate to marine organisms. i. generating reliable effects data.a scientific research program was initiated by the international molybdenum association (imoa) which addressed identified gaps in the environmental toxicity data for the molybdate ion (moo(4)(2-)). these gaps were previously identified during the preparation of eu-reach-dossiers for different molybdenum compounds (european union regulation on registration, evaluation, authorization and restriction of chemical substances; ec, 2006). evaluation of the open literature identified few reliable marine ...201222663766
identification of proteins with potential osteogenic activity present in the water-soluble matrix proteins from crassostrea gigas nacre using a proteomic approach.nacre, when implanted in vivo in bones of dogs, sheep, mice, and humans, induces a biological response that includes integration and osteogenic activity on the host tissue that seems to be activated by a set of proteins present in the nacre water-soluble matrix (wsm). we describe here an experimental approach that can accurately identify the proteins present in the wsm of shell mollusk nacre. four proteins (three gigasin-2 isoforms and a cystatin a2) were for the first time identified in wsm of ...201222666151
a hemocyte gene expression signature correlated with predictive capacity of oysters to survive vibrio infections.the complex balance between environmental and host factors is an important determinant of susceptibility to infection. disturbances of this equilibrium may result in multifactorial diseases as illustrated by the summer mortality syndrome, a worldwide and complex phenomenon that affects the oysters, crassostrea gigas. the summer mortality syndrome reveals a physiological intolerance making this oyster species susceptible to diseases. exploration of genetic basis governing the oyster resistance or ...201222708697
structural elucidation of molecular species of pacific oyster ether amino phospholipids by normal-phase liquid chromatography/negative-ion electrospray ionization and quadrupole/multiple-stage linear ion-trap mass spectrometry.although marine oysters contain abundant amounts of ether-linked aminophospholipids, the structural identification of the various molecular species has not been reported. we developed a normal-phase silica liquid chromatography/negative-ion electrospray ionization/quadrupole multiple-stage linear ion-trap mass spectrometric (nplc-ni-esi/q-trap-ms(3)) method for the structural elucidation of ether molecular species of serine and ethanolamine phospholipids from marine oysters. the major advantages ...201222713920
thermal treatment as a method to control transfers of invasive biofouling species via vessel sea chests.this study examined the efficacy of heated seawater for the treatment and remediation of fouled vessel sea chest habitats. in laboratory trials, three temperature regimes (37.5°c for 60 min, 40°c for 30min and 42.5°c for 20 min) were tested on a range of temperate taxa commonly found in sea chests. field validation trials further assessed the efficacy of heat treatment within a replica sea chest environment. during laboratory trials, 100% mortality was achieved across all three treatments for th ...201222732144
environmental stress increases selection against and dominance of deleterious mutations in inbred families of the pacific oyster crassostrea gigas.the deleterious effects of inbreeding are well documented and of major concern in conservation biology. stressful environments have generally been shown to increase inbreeding depression; however, little is known about the underlying genetic mechanisms of the inbreeding-by-stress interaction and to what extent the fitness of individual deleterious mutations is altered under stress. using microsatellite marker segregation data and quantitative trait locus (qtl) mapping methods, i performed a geno ...201222747636
effect of zinc sacrificial anode degradation on the defence system of the pacific oyster, crassostrea gigas: chronic and acute exposures.two types of exposures were performed to assess the effects of zinc released from sacrificial anode degradation: a chronic exposure, in which oysters were exposed to 0.53±0.04 mg zn l(-1) for 10 weeks, and an acute exposure, where oysters were exposed to 10.2±1.2 mg zn l(-1) for 1 week. at the end of the acute exposure experiment, 81.8% mortality was recorded. in contrast, no mortality was detected after 10 weeks exposure. moreover, all of the immune system biomarkers studied, except the number ...201222770699
a novel tissue inhibitor of metalloproteinase in blood clam tegillarca granosa: molecular cloning, tissue distribution and expression analysis.tissue inhibitor of metalloproteinases (timps) were originally characterized as inhibitors of matrix metalloproteinases (mmps), but their range of activities has been found to be broader as it includes the inhibition of several of the mmps, etc. the cdna encoding timp-4-like gene from blood clam tegillarca granosa (designated as tg-timp-4-like) which is the first tissue inhibitor of metalloproteinase identified in blood clams, was cloned and characterized. it was of 1164 bp, and an open reading ...201222771965
innervation of bivalve larval catch muscles by serotonergic and fmrfamidergic neurons.bivalve larvae use catch muscles for rapid shell closure and maintenance of the closed condition. we used specific antibodies against the muscle proteins together with phalloidin and neuronal markers, fmrfamide and serotonin (5-ht), to analyze mutual distribution of muscle and neuronal elements in larvae of the mussel, mytilus trossulus, and the oyster, crassostrea gigas. at trochophore and early veliger stages no anatomical connections between muscular and nervous system were detected. by the p ...201222776498
the antimicrobial defense of the pacific oyster, crassostrea gigas. how diversity may compensate for scarcity in the regulation of resident/pathogenic microflora.healthy oysters are inhabited by abundant microbial communities that vary with environmental conditions and coexist with immunocompetent cells in the circulatory system. in crassostrea gigas oysters, the antimicrobial response, which is believed to control pathogens and commensals, relies on potent oxygen-dependent reactions and on antimicrobial peptides/proteins (amps) produced at low concentrations by epithelial cells and/or circulating hemocytes. in non-diseased oysters, hemocytes express bas ...201222783227
a new species of gymnophallid (digenea) and an amended diagnosis of the genus gymnophalloides fujita, 1925.morphological and molecular evidence suggest that specimens formerly described as lacunovermis sp. from nacella (patinigera) spp. (patellogastropoda: patellidae) belong to a new species of gymnophalloides fujita, 1925 . based on the new information, they are identified as gymnophalloides nacellae n. sp. the new species differs from gymnophalloides tokiensis, gymnophalloides seoi , and gymnophalloides heardi mainly through the presence of a group of papillae located on the ventral surface between ...201322803608
evidence for a plastic dual circadian rhythm in the oyster crassostrea gigas.although a significant body of literature has been devoted to the chronobiology of aquatic animals, how biological rhythms function in molluscan bivalves has been poorly studied. the first objective of this study was to determine whether an endogenous circadian rhythm does exist in the oyster, crassostrea gigas. the second objective was to characterize it in terms of robustness. to answer these questions, the valve activity of 15 oysters was continuously recorded for 2 mo in the laboratory under ...201222823869
depuration of oysters (crassostrea gigas) contaminated with vibrio parahaemolyticus and vibrio vulnificus with uv light and chlorinated seawater.the efficacy of depuration using uv light and chlorinated seawater for decontaminating vibrio parahaemolyticus and vibrio vulnificus from oysters was investigated. oysters were contaminated with a five-strain cocktail of v. parahaemolyticus or v. vulnificus to levels of 10(4) to 10(5) cfu ml(-1) for bioaccumulation. the depuration was conducted in a closed system in which 350 liters of seawater was recirculated at a rate of 7 liters/min for 48 h at room temperature. counts of v. parahaemolyticus ...201222856577
purification and antimicrobial function of ubiquitin isolated from the gill of pacific oyster, crassostrea gigas.an antimicrobial polypeptide was purified from an acidified gill extract of pacific oyster (crassostrea gigas) by c(18) reversed-phase hplc. the purified polypeptide had a molecular weight of 8471da containing 74 amino acid residues. comparison of the obtained n-terminal sequences with those of others revealed that it was identical to ubiquitin reported from other species and named cgubiquitin. cgubiquitin showed broad potent antimicrobial activity against gram-positive and -negative bacteria in ...201322858580
proteomic identification of quality factors for oocytes in the pacific oyster crassostrea gigas.we used a 2-de proteomic approach to identify abundant proteins linked to oocyte quality in the pacific oyster crassostrea gigas, an economically important bivalve. oocyte quality of 14 females was estimated by recording fertilisation and early developmental success until d-larval stage under controlled conditions. proteins that were differentially expressed between females showing high or low oocyte quality were identified by nano-liquid chromatography tandem mass spectrometry. twelve up-accumu ...201222878033
genomic characterization and expression profiles upon bacterial infection of a novel cystatin b homologue from disk abalone (haliotis discus discus).cystatins are a large family of cysteine proteinase inhibitors which are involved in diverse biological and pathological processes. in the present study, we identified a gene related to cystatin superfamily, abcyt b, from disk abalone haliotis discus discus by expressed sequence tag (est) analysis and bac library screening. the complete cdna sequence of abcyt b is comprised of 1967 nucleotides with a 306 bp open reading frame (orf) encoding for 101 amino acids. the amino acid sequence consists o ...201222878425
characteristics and expression patterns of the lipopolysaccharide-induced tnf-α factor (litaf) gene family in the pacific oyster, crassostrea gigas.lipopolysaccharide-induced tumor necrosis factor-alpha factor (litaf) is a novel transcription factor responsible for lipopolysaccharide (lps)-induced transcription of tumor necrosis factor-alpha. here, we identified and characterized five new litaf genes in a mollusk, crassostrea gigas. the complete cdna sequences of these newly-cloned cglitafs each contain one small orf encoding putative proteins ranging from 67 to 132 amino acids in length. each cglitaf, except litaf2, includes a conserved do ...201222902610
transformation of paralytic shellfish poisoning toxins in crassostrea gigas and pecten maximus reference materials.matrix reference materials are an important requirement for the assessment of method performance characteristics and for routine quality control. in the field of marine toxin testing where biological assays have been used and where modern analytical testing methods are now becoming available, this requirement has become an urgent one. various approaches are utilised for preparation of such materials in the absence of available naturally occurring toxic shellfish samples. toxin-free shellfish may ...201222921579
analysis of pacific oyster larval proteome and its response to high-co2.most calcifying organisms show depressed metabolic, growth and calcification rates as symptoms to high-co(2) due to ocean acidification (oa) process. analysis of the global expression pattern of proteins (proteome analysis) represents a powerful tool to examine these physiological symptoms at molecular level, but its applications are inadequate. to address this knowledge gap, 2-de coupled with mass spectrophotometer was used to compare the global protein expression pattern of oyster larvae expos ...201222921897
infection status of estuarine fish and oysters with intestinal fluke metacercariae in muan-gun, jeollanam-do, korea.the source of human infection with intestinal flukes was surveyed in estuarine fishes, including the dotted gizzard shad, common sea bass, common blackish goby, redlip mullet, black sea bream, and oyster collected from muan-gun, jeollanam-do, korea during august and september 2007. collected fishes and oysters were artificially digested in pepsin-hcl solution and examined under a stereomicroscope. in 36 shads (konosirus punctatus) and 20 basses (lateolabrax japonicus) examined, heterophyopsis co ...201222949748
genetic evidence for the uncoupling of local aquaculture activities and a population of an invasive species--a case study of pacific oysters (crassostrea gigas).human-mediated introduction of nonnative species into coastal areas via aquaculture is one of the main pathways that can lead to biological invasions. to develop strategies to counteract invasions, it is critical to determine whether populations establishing in the wild are self-sustaining or based on repeated introductions. invasions by the pacific oyster (crassostrea gigas) have been associated with the growing oyster aquaculture industry worldwide. in this study, temporal genetic variability ...201222952271
purification and characterization of a novel peptide with inhibitory effects on colitis induced mice by dextran sulfate sodium from enzymatic hydrolysates of crassostrea gigas.the anti-inflammatory activity of purified peptides from crassostrea gigas (c. gigas) hydrolysates was studied. to prepare hydrolysates from c. gigas, we used eight different proteinases and the anti-inflammatory activities were determined using a nitric oxide (no) assay in raw264.7 cells. among the hydrolysates, protamex hydrolysates showed the highest anti-inflammatory activity. we separated and purified the total hydrolysate using an ultrafiltration membrane system and consecutive chromatogra ...201222960100
determination of brevetoxins in shellfish by lc/ms/ms: single-laboratory validation.a single-laboratory validation is reported for an lc/ms/ms quantification of six brevetoxins in four matrixes (greenshell mussel, eastern oyster, hard clam, and pacific oyster). recovery and precision data were collected from seven analytical batches using shellfish flesh at 0.05 mg/kg. method recoveries and within-laboratory reproducibility ranged from 73 to 112%, with an rsd between 14 and 18% for brevetoxin-3, brevetoxin b5, brevetoxin b2, and s-desoxy brevetoxin b2. the recovery and within-l ...201422970578
characterization of genes involved in ceramide metabolism in the pacific oyster (crassostrea gigas).the lipid signaling molecule, ceramide, is a key component of the vertebrate stress response, however, there is limited information concerning its role in invertebrate species. in order to identify genes involved in ceramide metabolism in bivalve molluscs, pacific oyster genomic resources were examined for genes associated with ceramide metabolism and signaling.201222974230
histological survey of pacific oysters crassostrea gigas (thunberg) in galicia (nw spain).in galicia, there is an increasingly interest among representatives of the oyster industry in the development of pacific oyster crassostrea gigas culture. nevertheless severe mortalities and emerging health problems in this species have been recently reported in european farming areas. a histological survey was performed from 2004 to 2009 to assess health status in both cultured and wild galician oysters. different symbiotic organisms and conditions were detected, including viral gametocytic hyp ...201222985902
the oyster genome reveals stress adaptation and complexity of shell formation.the pacific oyster crassostrea gigas belongs to one of the most species-rich but genomically poorly explored phyla, the mollusca. here we report the sequencing and assembly of the oyster genome using short reads and a fosmid-pooling strategy, along with transcriptomes of development and stress response and the proteome of the shell. the oyster genome is highly polymorphic and rich in repetitive sequences, with some transposable elements still actively shaping variation. transcriptome studies rev ...201222992520
effect of chronic exposure to zinc in young spats of the pacific oyster (crassostrea gigas).the marine coastal environment is exposed to a mixture of environmental pollutants of anthropogenic origin, resulting in chronic low concentrations of contaminants. as a consequence, most coastal marine species are exposed to low doses of such pollutants during their entire life. many marine species live for years in their natural environment, whereas they do not under laboratory exposure conditions. using early stages of development in laboratory work allows animals to be chronically exposed fr ...201222997013
in situ distribution and characterization of the organic content of the oyster shell crassostrea gigas (mollusca, bivalvia).cultivation of commercial oysters is now facing the possible influence of global change in sea water composition, commonly referred to as "ocean acidification". in order to test the potential consequence of the predicted environmental changes, a cultivation experiment was carried out. the left and right valves of the oyster shell crassostrea gigas differ in their structure; moreover, lenses of non compact layers are irregular. the shell layers of juvenile c. gigas are studied using a variety of ...201323022314
transcriptomic responses to salinity stress in the pacific oyster crassostrea gigas.low salinity is one of the main factors limiting the distribution and survival of marine species. as a euryhaline species, the pacific oyster crassostrea gigas is considered to be tolerant to relative low salinity. the genes that regulate c. gigas responses to osmotic stress were monitored using the next-generation sequencing of whole transcriptome with samples taken from gills. by rnaseq technology, transcript catalogs of up- and down-regulated genes were generated from the oysters exposed to l ...201223029449
effect of environmental impact to molecular expression of heat-shock protein (hsp70) in oyster crassostrea gigas from gamak bay, korea.the cdna of crassostrea gigas hsp70 was cloned and rapid amplification of cdna (race) techniques were used. the full length of hsp70 cdna was 2045 bp, consisting of a 5' terminal untranslated region (utr) of 80 bp, a 3' terminal utr 146 bp, and an open reading frame (orf) of 1829 bp encoding deduced 620 amino acids. the hsp70 cdna contained hsp70 family signatures, atp-gtp binding site motif, tetrapeptide (ggmp) and conserved carboxyl terminal region (eevd) at c-terminal of deduced amino acid se ...201223029911
a previously undescribed ostreid herpes virus 1 (oshv-1) genotype detected in the pacific oyster, crassostrea gigas, in ireland.significant mortalities of the pacific oyster, crassostrea gigas, have been reported worldwide since the 1950s. the impact these re-occurring mortality events have had on the c. gigas industry has highlighted the necessity to determine the factors that may be causing these mortalities. this study investigated the possible role of ostreid herpes virus (oshv-1) in c. gigas mortalities over 2 successive summers at 2 study areas in ireland. a single sample of adult c. gigas, which had been experienc ...201223036593
reactive oxygen species in unstimulated hemocytes of the pacific oyster crassostrea gigas: a mitochondrial involvement.the pacific oyster crassostrea gigas is a sessile bivalve mollusc whose homeostasis relies, at least partially, upon cells circulating in hemolymph and referred to as hemocytes. oyster's hemocytes have been reported to produce reactive oxygen species (ros), even in absence of stimulation. although ros production in bivalve molluscs is mostly studied for its defence involvement, ros may also be involved in cellular and tissue homeostasis. ros sources have not yet been described in oyster hemocyte ...201223056359
study of the antioxidant capacity in gills of the pacific oyster crassostrea gigas in link with its reproductive investment.energy allocation principle is a core element of life-history theory in which "the cost of reproduction" corresponds to an acceleration of senescence caused by an increase in reproductive investment. in the "theory of aging", senescence is mainly due to the degradation of lipids, proteins and dna by reactive oxygen species (ros), by-products of oxidative metabolism. some studies have shown that oxidative stress susceptibility could be a cost of reproduction. the present study investigates the ef ...201323073513
impact of weather conditions on escherichia coli accumulation in oysters of the thau lagoon (the mediterranean, france).the thau lagoon shellfish are regularly impacted by microbial pollution of faecal origin, which cause european health standards to be exceeded and closure of the shellfish harvest. the aims of this study were to investigate the impact of weather and hydrological conditions on escherichia coli (e. coli) accumulation factor (af) between water and oysters and to evaluate the relevance of the use of this ratio for the purpose of sanitary risk assessment.201323075079
embryotoxic and genotoxic effects of heavy metals and pesticides on early life stages of pacific oyster (crassostrea gigas).this study evaluated embryotoxicity and genotoxicity of two dissolved metals copper and cadmium (cu and cd) and two pesticides (metolachlor and irgarol) occurring in arcachon bay (sw france) in pacific oyster (crassostrea gigas) larvae and investigated the relationship between those two endpoints. embryotoxicity was measured by calculating the percentage of abnormal d-shaped larvae and genotoxicity was evaluated with dna strand breaks using the comet assay. after 24h exposure, significant increa ...201223122627
arsenic and arsenic species in cultured oyster (crassostrea gigas and c. corteziensis) from coastal lagoons of the se gulf of california, mexico.the aim of this study was to evaluate the bioavailability of arsenic (as) through cultured oyster crassostrea gigas and crassostrea corteziensis from four coastal lagoons (se gulf of california). organisms were collected in two seasons (rainy and dry season), and they were analyzed for total arsenic and chemical speciation of this element. the concentrations of as in oyster soft tissue fluctuated between 5.44 and 9.56 μg/g for rainy season and 6.46 and 8.33 μg/g for dry season (dry weight) in c. ...201323129525
effects of non-indigenous oysters on microbial diversity and ecosystem functioning.invasive ecosystem engineers can physically and chemically alter the receiving environment, thereby affecting biodiversity and ecosystem functioning. the pacific oyster, crassostrea gigas, invasive throughout much of the world, can establish dense populations monopolising shorelines and possibly altering ecosystem processes including decomposition and nutrient cycling. the effects of increasing cover of invasive c. gigas on ecosystem processes and associated microbial assemblages in mud-flats we ...201223144762
responses of b-esterase enzymes in oysters (crassostrea gigas) transplanted to pesticide contaminated bays form the ebro delta (ne, spain).marine bivalves such as oysters are widely used as bioindicators to monitor marine coastal pollution. this study aimed to use b-esterase activity responses in oysters (crassostrea gigas) cultured in ebro delta bays to monitor environmental effects of pesticides. the b esterases investigated were acetylcholinesterase, propionylcholinesterase, and carboxylesterase and their activities were measured in adductor muscle and gills from oysters transplanted in ebro delta bays where the are traditionall ...201323168234
characterisation of norovirus contamination in an irish shellfishery using real-time rt-qpcr and sequencing analysis.norovirus (nov) is the single most important agent of foodborne viral gastroenteritis worldwide. bivalve shellfish, such as oysters, grown in areas contaminated with human faecal waste may become contaminated with human pathogens including nov. a study was undertaken to investigate nov contamination in oysters (crassostrea gigas) from a shellfishery over a 24month period from october 2007 to september 2009. oyster samples were collected monthly from a commercial shellfish harvest area classified ...201223177049
paralytic toxins accumulation and tissue expression of α-amylase and lipase genes in the pacific oyster crassostrea gigas fed with the neurotoxic dinoflagellate alexandrium catenella.the pacific oyster crassostrea gigas was experimentally exposed to the neurotoxic alexandrium catenella and a non-producer of psts, alexandrium tamarense (control algae), at concentrations corresponding to those observed during the blooming period. at fixed time intervals, from 0 to 48 h, we determined the clearance rate, the total filtered cells, the composition of the fecal ribbons, the profile of the psp toxins and the variation of the expression of two α-amylase and triacylglecerol lipase pr ...201223203275
denman island disease (causative agent mikrocytos mackini) in a new host, kumamoto oysters crassostrea sikamea.mikrocytos mackini, causative agent of denman island disease in pacific oysters crassostrea gigas and other oyster species, was found in 2011 in a previously unreported host, the kumamoto oyster c. sikamea, in humboldt bay, california, usa. the detection was also the first reported finding of m. mackini in california. prevalence was estimated as high as approximately 27% from pooled samples analyzed by pcr. higher prevalence appeared related to longer residence time in the bay and somewhat colde ...201223209079
preference alters consumptive effects of predators: top-down effects of a native crab on a system of native and introduced prey.top-down effects of predators in systems depend on the rate at which predators consume prey, and on predator preferences among available prey. in invaded communities, these parameters might be difficult to predict because ecological relationships are typically evolutionarily novel. we examined feeding rates and preferences of a crab native to the pacific northwest, cancer productus, among four prey items: two invasive species of oyster drill (the marine whelks urosalpinx cinerea and ocenebra ino ...201223236472
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