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Showing papers on "Oyster published in 2006"


Journal ArticleDOI
TL;DR: An international outbreak linked to oyster consumption involving a group of over 200 people in Italy and 127 total subjects in 13 smaller clusters in France was analyzed using epidemiological and clinical data and shellfish samples, and heavy rain was responsible for the accidental contamination of seafood.
Abstract: An international outbreak linked to oyster consumption involving a group of over 200 people in Italy and 127 total subjects in 13 smaller clusters in France was analyzed using epidemiological and clinical data and shellfish samples. Environmental information from the oyster-producing area, located in a lagoon in southern France, was collected to investigate the possible events leading to the contamination. Virologic analyses were conducted by reverse transcription-PCR (RT-PCR) using the same primer sets for both clinical and environmental samples. After sequencing, the data were analyzed through the database operated by the scientific network FoodBorne Viruses in Europe. The existence of an international collaboration between laboratories was critical to rapidly connect the data and to fully interpret the results, since it was not obvious that one food could be the link because of the diversity of the several norovirus strains involved in the different cases. It was also demonstrated that heavy rain was responsible for the accidental contamination of seafood, leading to a concentration of up to hundreds of genomic copies per oyster as detected by real-time RT-PCR.

258 citations


Journal ArticleDOI
TL;DR: Specific binding of virus to oysters can selectively concentrate a human pathogen, and this binding has the potential to selectively concentrate human pathogens.
Abstract: The primary pathogens related to shellfishborne gastroenteritis outbreaks are noroviruses. These viruses show persistence in oysters, which suggests an active mechanism of virus concentration. We investigated whether Norwalk virus or viruslike particles bind specifically to oyster tissues after bioaccumulation or addition to tissue sections. Since noroviruses attach to carbohydrates of the histo-blood group family, tests using immunohistochemical analysis were performed to evaluate specific binding of virus or viruslike particles to oyster tissues through these ligands. Viral particles bind specifically to digestive ducts (midgut, main and secondary ducts, and tubules) by carbohydrate structures with a terminal N-acetylgalactosamine residue in an α linkage (same binding site used for recognition of human histo-blood group antigens). These data show that the oyster can selectively concentrate a human pathogen and that conventional depuration will not eliminate noroviruses from oyster tissue.

251 citations


Journal ArticleDOI
TL;DR: An increase of temperature induced an increase of haemocyte mortality, in both in vitro and in vivo experiments, and temperature modulated aminopeptidase activity and an in vitro decrease of salinity was associated with cell mortality.

219 citations


Journal ArticleDOI
TL;DR: Combined effects of temperature and a toxic metal, cadmium (Cd), on energy metabolism of oysters were studied in a model marine bivalve and combined stressors appeared to override the capability for aerobic energy production resulting in impaired stress tolerance.

200 citations


Journal ArticleDOI
TL;DR: The model successfully reproduced quantitatively the growth and reproduction and the timing of spawning in the Pacific oyster and was proposed to propose several promising perspectives of application for this model in shellfish ecosystems.

200 citations


Journal ArticleDOI
TL;DR: The results suggest that Cg-def gene is continuously expressed in the mantle and would play a key role in oyster by providing a first line of defense against pathogen colonization.

197 citations


Journal ArticleDOI
TL;DR: Since reef macrofauna include many important fish prey species, oyster reef restoration may have the potential to augment fish production by increasing fish prey densities and fish foraging efficiency.

192 citations


Journal ArticleDOI
TL;DR: The interactions between the Pacific oyster immune system and Vibrio aestuarianus strain 01/32, a pathogenic bacterium originally isolated from moribund oysters, are investigated, providing new insights into the cellular and molecular bases of the host-pathogen interactions in C. gigas oyster.

175 citations


Journal ArticleDOI
TL;DR: In this paper, a semi-nested RT-PCR was used to detect norovirus in shellfish from oyster farms in the Netherlands and imported from other European countries.

162 citations


Journal ArticleDOI
TL;DR: It is concluded 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.

140 citations


Journal ArticleDOI
TL;DR: The species composition of fish and decapods was more strongly related to location within the estuary than to habitat, andFish and decapod species composition responded on a larger landscape scale than invertebrate assemblages.
Abstract: The complexity of habitat structure created by aquatic vegetation is an important factor determining the diversity and composition of soft-sediment coastal communities. The introduction of estuarine organisms, such as oysters or other forms of aquaculture, that compete with existing forms of habitat structure, such as seagrass, may affect the availability of important habitat refugia and foraging resources for mobile estuarine fish and decapods. Fish and invertebrate communities were compared between adjacent patches of native seagrass (Zostera marina), nonnative cultured oyster (Crassostrea gigas), and unvegetated mudflat within a northeastern Pacific estuary. The composition of epibenthic meiofauna and small macrofaunal organisms, including known prey of fish and decapods, was significantly related to habitat type. Densities of these epifauna were significantly higher in structured habitat compared to unstructured mudflat. Benthic invertebrate densities were highest in seagrass. Since oyster aquaculture may provide a structural substitute for seagrass being associated with increased density and altered composition of fish and decapod prey resources relative to mudflat, it was hypothesized that this habitat might also alter habitat preferences of foraging fish and decapods. The species composition of fish and decapods was more strongly related to location within the estuary than to habitat, and fish and decapod species composition responded on a larger landscape scale than invertebrate assemblages. Fish and decapod species richness and the size of ecologically and commercially important species, such as Dungeness crab (Cancer magister), English sole (Parophrys vetulus), or lingcod (Ophiodon elongatus), were not significantly related to habitat type.

Journal ArticleDOI
TL;DR: Oyster dry weights, carbohydrate and lipid contents, energetic adenylate charge, and hemocyte parameters of oysters were significantly affected by reproductive processes related to seasonal temperature variation and, to a lesser extent, by the dietary rations.

Journal ArticleDOI
TL;DR: In this article, the authors show that oysters are unlikely to have controlled blooms, despite the fact that sediment cores suggest that pre-colonial spring blooms were smaller than at present.
Abstract: Restoration of the oyster Crassostrea virginica population in Chesapeake Bay is often advocated as an easy solution for controlling phytoplankton blooms. Even at their pre-colonial densi- ties, oysters are unlikely to have controlled blooms, despite the fact that sediment cores suggest that pre-colonial spring blooms were smaller than at present. Lack of access to all bay water and low springtime filtration rates would make it impossible for oysters to control the spring bloom and the resulting summer hypoxia. Previous studies have overestimated potential oyster filtration rates, because they extrapolated summer rates to spring conditions that are 20°C cooler. Previous studies have also assumed that oysters have access to all phytoplankton, without considering the spatial sep- aration. In Chesapeake Bay, oysters and the spring bloom are separated horizontally owing to the size of the bay and its small tidal amplitude. Indeed, a multi-species guild of suspension feeders now pre- sent in the bay should have a filtration capacity approaching that of pre-colonial oysters, but it does not control the bloom. Actual oyster filtration potential must be lower than many advocates of oyster restoration assume, and replenishing the bay with oysters is not the means of controlling blooms and hypoxia.

Journal ArticleDOI
TL;DR: The Neighbor-joining tree topology constructed on the basis of genetic distances between populations showed a clear separation of the northern three populations and southern two populations, suggesting that geographically separated cultured populations of C. gigas could be genetically differentiated unless seeds are transplanted among them.

Journal ArticleDOI
TL;DR: A reduction in population abundance, brought on by an unprecedented 6 years of low recruitment, has reduced shell input through natural mortality on Delaware Bay oyster beds, permitting the reconstruction of the time history of shell since 1998 and estimation of the rates of shell addition and loss.
Abstract: A reduction in population abundance, brought on by an unprecedented 6 years of low recruitment, has reduced shell input through natural mortality on Delaware Bay oyster beds. Quantitative stock surveys provide an estimate of surficial shell over the same time period, permitting the reconstruction of the time history of shell since 1998 and estimation of the rates of shell addition and loss. Shell loss rates were unexpectedly high. In most cases, half of the shell added to an oyster bed in Delaware Bay in a given year is lost over a subsequent period of 2–10 years. Unexpectedly, the shortest half-lives, typically two to three years, are at intermediate salinities. Half-lives increase upbay into lower salinity and downbay into higher salinity to about 10 years. Minimal shell doubling times were calculated under the assumption of no shell loss, a maximum accretion rate. Minimal doubling times vary from somewhat less than a decade to more than a score of years. Doubling times of decadal scale emphasize that shell has the potential to accumulate rapidly on human time scales. The rarity of definitive documentation of shell accumulation, in terms of reef vertical accretion or lateral expansion, can only be explained if most shell produced yearly does not long remain recognizably intact. Doubling times are not rapid on the scale of oyster generation time, however. Management of essential fish habitat in the estuarine realm must include management of the shell budget and management of commercial shell-producing species must include the provision of animals as carbonate producers for habitat maintenance. Shell, at least in estuarine habitats, may have low preservational potential, even in areas that, when preserved, will appear to be shellbeds. The biases in the fossil record may not be minimized in shell-rich environments of preservation because shelliness does not imply good preservability.

Journal ArticleDOI
TL;DR: High survival and growth rates may compensate for years with low recruitment, and may therefore allow a fast population increase, which may lead to restrictions on habitat use by native mussels in the Wadden Sea.

Journal ArticleDOI
TL;DR: It is demonstrated that recent anthropogenic inputs of oysters affect the reef species assemblage more strongly than algal epibionts, causing a reduction in new recruits that over the long run may cause significant damage to the reef structure itself.
Abstract: Biogenic structures built by ecosystem engineers such as corals, bivalves, polychaetes, and sea grasses provide habitat for benthic vertebrates and invertebrates. The polychaete Sabellaria alveolata is an important foundation species whose reef structure adds topographic complexity and high levels of biodiversity to the otherwise low-relief, low diversity, soft-bottom environments in the Bay of Mont Saint-Michel, France, where the largest such reef formations in Europe are found. In this bay, reefs are being increasingly colonised by oysters (Crassostrea gigas) from local aquaculture operations and by green algae (Ulva sp.) due to the increasing inputs of nitrates from terrestrial origin. The purpose of this study was to investigate the possible impacts of epibiotic oysters and green algae on the S. alveolata population and reef community structure in the Bay of Mont Saint-Michel, France. Univariate and multivariate comparisons of macrofauna were conducted for five reef types: controls (no epibionts), low oyster density, high oyster density, green algae, and oyster and green algae. Results showed that all the three reef types with oysters had significantly higher species richness and diversity values than control and algae-only reef types. Pairwise ANOSIM and SIMPER comparisons of controls versus the four reef types with epibionts revealed that all three of the reef types with oysters were significantly different from controls, but there was no significant difference between controls and algae-only reef types. A striking feature of the reef comparisons is that no single species in this species-rich system contributed more than 8.86% to the dissimilarity between the reef types. Thus, k-dominance curves for species abundances were not effective in revealing differences among the reef types. Our results demonstrate that recent anthropogenic inputs of oysters affect the reef species assemblage more strongly than algal epibionts. In addition, epibionts, especially green algae, alter S. alveolata population structure, causing a reduction in new recruits that over the long run may cause significant damage to the reef structure itself. These results are a first step towards understanding anthropogenic threats to S. alveolata reefs and may be useful in the development of strategies for their protection and management.

Journal ArticleDOI
TL;DR: Fundamental data is obtained for further establishing an energy budget model and assessing the carrying capacity for cultivation of C. gigas in north China to determine differences among these parameters that act as a function of seasonal variation.

Journal ArticleDOI
TL;DR: This study shows carbohydrate anabolism contributed in the physiological stress leading to mortality events in oysters reared using “on bottom” culture conditions in Marennes–Oleron bay.

Journal ArticleDOI
TL;DR: This study scans the genome of the eastern oyster with a large number of amplified fragment length polymorphism (AFLP) markers before and after Dermo-inflicted mortalities, suggesting that post-mortality shifts in genotype frequency were not random, but linked to Dermo/summer mortality-resistance QTLs.

Journal ArticleDOI
TL;DR: This is the first study monitoring hemocyte parameters of wild diploids, hatchery bred diploid and triploid oysters reared in the field and results showed that triploids presented the highest values for several hemocytes parameters and the lowest mortality rates.

Journal ArticleDOI
TL;DR: It is argued that the potential impact of oyster culture on the environment should be assessed on the basis of parameters other than sediment redox and sulfide levels, as the upper layers of the sediment are frequently subjected to re-suspension by wave activity and physical erosion by winter ice.

Journal ArticleDOI
TL;DR: The stable isotope ratios of carbon (d 13 C) and nitrogen (d 15 N) of the muscle, ctenidia and viscera of the Sydney rock oyster, Saccostrea glomerata, showed the dilution and assimilation of tertiary treated sewage along an estuarine gradient.
Abstract: The stable isotope ratios of carbon (d 13 C) and nitrogen (d 15 N) of the muscle, ctenidia and viscera of the Sydney rock oyster, Saccostrea glomerata, showed the dilution and assimilation of tertiary treated sewage along an estuarine gradient. The enriched 15 N values of oyster ctenidia and viscera from within 50 m of the sewage outfall indicated the use of 15 N-enriched tertiary treated sewage effluent (16 G 2.3&) as a nutrient source. The effect of sewage nitrogen on oyster d 15 N was localised, with oysters 5 km upstream and downstream of the outfall not significantly enriched. Viscera d 15 N was most sensitive to sewage nutrients and d 13 C significantly defined an ocean-to-estuarine gradient. High variance in isotope ratios of viscera compromised its use as an indicator of anthropogenic nutrients, and this also reduced the utility of whole-body stable isotope ratios. Ctenidia was the most useful indicator tissue of sewage discharge at the scale of this study, being consistently and significantly enriched in d 15 N close to the sewage outfall and d 13 C clearly defined an estuarine gradient with less internal variability than viscera. Muscle d 15 N was least sensitive to sewage effluent and showed the least variability, making it more suited to investigations of anthropogenic nutrient enrichment over larger spatio-temporal scales. 2005 Elsevier Ltd. All rights reserved.

Journal ArticleDOI
TL;DR: Selecting oysters for resistance to QX disease did not appear to confer resistance to winter mortality and the converse also applied.
Abstract: A breeding program for Sydney rock oysters Saccostrea glomerata (Gould, 1850) has been selecting oysters for resistance to QX disease (Marteilia sydneyi) and winter mortality (Bonamia roughleyi) for three generations at three sites in Georges River, New South Wales, Australia. The experimental sites are located at the upper, middle and lower reaches of oyster growing areas in the estuary. QX disease mainly occurs in the middle and upper reaches and is most severe at the latter. Winter mortality on the other hand occurs mainly at the lower and middle reaches and is most severe at the former. Progeny of third-generation Sydney rock oyster breeding lines were evaluated for resistance to both QX disease and winter mortality against a non-selected control. Line 1, selected for QX disease resistance at the upper estuary site, had excellent resistance to one season of exposure to disease, but suffered high mortality during the second season of exposure. However, these oysters had already reached market size of 50 g whole weight, with low mortality at 2 years of age, before the second episode of QX disease. Line 2 showed good improvement in resistance to both diseases, whereas Line 3, was the most resistant to winter mortality. Selection for resistance to QX disease did not appear to confer resistance to winter mortality and the converse also applied.

Journal ArticleDOI
TL;DR: Broadly adapted genotypes are required if a single line of selection is to improve Pacific oyster production throughout the heterogeneous growing environments found in the Pacific Northwest region of the United States.

Journal ArticleDOI
Cédric Bacher1, Aline Gangnery1
TL;DR: A Dynamic Energy Budget model of the oyster Crassostrea gigas is tested using published environmental data and growth data collected in Thau lagoon (France) and an Individual Based Model (IBM) of cultivated oyster populations, showing that IBM offers a powerful alternative to continuous equations when several physiological variables are involved.

Journal ArticleDOI
TL;DR: To determine if histo‐blood group antigens (HBGA) present in oyster gastrointestinal (GI) cells mediate accumulation of human noroviruses (NoV) in Oyster GI cells, a large number of oyster cells have been infected with HBGA.
Abstract: Aims: To determine if histo-blood group antigens (HBGA) present in oyster gastrointestinal (GI) cells mediate accumulation of human noroviruses (NoV) in oyster GI cells. Methods and Results: HBGA-specific monoclonal antibodies (MAbs) were used to determine the presence of the corresponding HBGA in oyster GI cells. All oyster samples tested contained type A-like HBGA in GI tissue as measured by ELISA. Recombinant Norwalk virus viral like particles (rNVLP) were bound to plates coated with oyster GI homogenate. The binding was inhibited when rNVLPs were pre-incubated with MAbs specific for type A HBGA, or samples of human saliva from type A individuals. Co-localization of rNVLP and type A-like HBGA, but not type B-like or type H-like HBGA, on GI epithelial cells was observed by immunofluorescent histochemical staining and three-channel confocal scanning laser microscopy. Conclusion: Type A-like HBGA is present in oyster GI cells and responsible for binding of rNVLP. Significance and Impact of the Study: This is the first report of the presence of type A-like HBGA in oyster GI cells and the specific binding of rNVLP to type A-like HBGA on oyster GI cells. The results of this study suggest that human NoV concentrate in oyster GI cells by specific binding to concentrated type A-like HBGA rather than by a nonmolecular entrapment within the tissues.

Journal ArticleDOI
TL;DR: Multiresistant environmental strains were found, representing a potential threat to human health and testing isolates for antibiotic sensitivity.
Abstract: We analyzed the presence of Listeria spp. in oyster, fish, and seawater samples and tested isolates for antibiotic sensitivity. Listeria monocytogenes was found in 4.5% of fish samples and 8.3% of seawater samples and was not recovered from oysters. Multiresistant environmental strains were found, representing a potential threat to human health.

Journal ArticleDOI
TL;DR: Two new species, Trichoderma pleurotum and T. pleuroticola, associated with green mold disease of oyster mushroom in Korea are described and illustrated.
Abstract: This paper describes and illustrates two new species, Trichoderma pleurotum and T. pleuroticola, associated with green mold disease of oyster mushroom in Korea.

Journal ArticleDOI
TL;DR: Genotypic exact tests demonstrated significant levels of geographic differentiation overall, and a subtle pattern of isolation by distance (IBD), implying that local efforts to restore oyster populations will have local demographic payoffs, perhaps at the scale of tributaries or regional subestuaries within Chesapeake Bay.
Abstract: Intensive efforts are underway to restore depleted stocks of Crassostrea virginica in Chesapeake Bay. However, the extent of gene flow among local populations, an important force mediating the success of these endeavors, is poorly understood. Spatial and temporal population structures were examined in C. virginica from Chesapeake Bay using eight microsatellite loci. Deficits in heterozygosity relative to Hardy-Weinberg expectations were seen at all loci and were best explained by null alleles. Permutation tests indicated that heterozygote deficiency reduced power in tests of differentiation. Nonetheless, genotypic exact tests demonstrated significant levels of geographic differentiation overall, and a subtle pattern of isolation by distance (IBD) was observed. Comparisons between age classes failed to show differences in genotype frequencies, allelic richness, gene diversity, or differentiation as measured by F ST , contrary to predictions made by the sweepstakes hypothesis. The IBD pattern could reflect an evolutionary equilibrium established because local gene flow predominates, or be influenced in either direction by recent anthropogenic activities. An evolutionary interpretation appears justified as more parsimonious, implying that local efforts to restore oyster populations will have local demographic payoffs, perhaps at the scale of tributaries or regional sub-estuaries within Chesapeake Bay.