Science.gov

Sample records for oysters

  1. Oysters and Oyster Reef Communities in Florida.

    ERIC Educational Resources Information Center

    Knight, Jean; Bly, Joe

    1989-01-01

    The habitat, life history, feeding, classification, anatomy and pearl production of the American oyster (Crassostrea virginica) are presented. A list of other oyster reef inhabitants and predators is provided. Harvest and habitat loss are discussed. (CW)

  2. 21 CFR 161.136 - Olympia oysters.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Olympia oysters. 161.136 Section 161.136 Food and... oysters. Olympia oysters, raw Olympia oysters, shucked Olympia oysters, are of the species Ostrea lurida and conform to the definition and standard of identity prescribed for oysters in § 161.130....

  3. 21 CFR 161.136 - Olympia oysters.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Olympia oysters. 161.136 Section 161.136 Food and... oysters. Olympia oysters, raw Olympia oysters, shucked Olympia oysters, are of the species Ostrea lurida and conform to the definition and standard of identity prescribed for oysters in § 161.130....

  4. 21 CFR 161.136 - Olympia oysters.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Olympia oysters. 161.136 Section 161.136 Food and... oysters. Olympia oysters, raw Olympia oysters, shucked Olympia oysters, are of the species Ostrea lurida and conform to the definition and standard of identity prescribed for oysters in § 161.130....

  5. 21 CFR 161.136 - Olympia oysters.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Olympia oysters. 161.136 Section 161.136 Food and... oysters. Olympia oysters, raw Olympia oysters, shucked Olympia oysters, are of the species Ostrea lurida and conform to the definition and standard of identity prescribed for oysters in § 161.130....

  6. 21 CFR 161.136 - Olympia oysters.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Olympia oysters. 161.136 Section 161.136 Food and... oysters. Olympia oysters, raw Olympia oysters, shucked Olympia oysters, are of the species Ostrea lurida and conform to the definition and standard of identity prescribed for oysters in § 161.130....

  7. 78 FR 62293 - Safety Zone, Oyster Festival 30th Anniversary Fireworks Display, Oyster Bay; Oyster Bay, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-15

    ... CFR Part 165 RIN 1625-AA00 Safety Zone, Oyster Festival 30th Anniversary Fireworks Display, Oyster Bay; Oyster Bay, NY AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on the navigable waters of Oyster Bay near Oyster Bay, NY for the...

  8. 21 CFR 161.130 - Oysters.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Oysters. 161.130 Section 161.130 Food and Drugs... CONSUMPTION FISH AND SHELLFISH Requirements for Specific Standardized Fish and Shellfish § 161.130 Oysters. (a) Oysters, raw oysters, shucked oysters, are the class of foods each of which is obtained by shucking...

  9. 21 CFR 161.130 - Oysters.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Oysters. 161.130 Section 161.130 Food and Drugs... CONSUMPTION FISH AND SHELLFISH Requirements for Specific Standardized Fish and Shellfish § 161.130 Oysters. (a) Oysters, raw oysters, shucked oysters, are the class of foods each of which is obtained by shucking...

  10. 21 CFR 161.130 - Oysters.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Oysters. 161.130 Section 161.130 Food and Drugs... CONSUMPTION FISH AND SHELLFISH Requirements for Specific Standardized Fish and Shellfish § 161.130 Oysters. (a) Oysters, raw oysters, shucked oysters, are the class of foods each of which is obtained by shucking...

  11. 21 CFR 161.130 - Oysters.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Oysters. 161.130 Section 161.130 Food and Drugs... CONSUMPTION FISH AND SHELLFISH Requirements for Specific Standardized Fish and Shellfish § 161.130 Oysters. (a) Oysters, raw oysters, shucked oysters, are the class of foods each of which is obtained by shucking...

  12. 21 CFR 161.130 - Oysters.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Oysters. 161.130 Section 161.130 Food and Drugs... CONSUMPTION FISH AND SHELLFISH Requirements for Specific Standardized Fish and Shellfish § 161.130 Oysters. (a) Oysters, raw oysters, shucked oysters, are the class of foods each of which is obtained by shucking...

  13. Oyster Fisheries App

    NASA Technical Reports Server (NTRS)

    Perez Guerrero, Geraldo A.; Armstrong, Duane; Underwood, Lauren

    2015-01-01

    This project is creating a cloud-enabled, HTML 5 web application to help oyster fishermen and state agencies apply Earth science to improve the management of this important natural and economic resource. The Oyster Fisheries app gathers and analyzes environmental and water quality information, and alerts fishermen and resources managers about problems in oyster fishing waters. An intuitive interface based on Google Maps displays the geospatial information and provides familiar interactive controls to the users. Alerts can be tailored to notify users when conditions in specific leases or public fishing areas require attention. The app is hosted on the Amazon Web Services cloud. It is being developed and tested using some of the latest web development tools such as web components and Polymer.

  14. Putting oysters under pressure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High pressure processing (HPP) is the most commercially important food processing technology in use now and is anticipated to remain of equal or greater importance during the next five to 10 years. This month’s column reviews the theory and current applications of HPP for oysters to improve their sa...

  15. The American Oyster.

    ERIC Educational Resources Information Center

    Thompson, Nancy E.

    The Maryland Marine Science Education Project has produced a series of mini-units in marine science education for the junior high/middle school classroom. This unit focuses on the American oyster. Although the unit specifically treats the Chesapeake Bay, it may be adapted for use with similar estuarine systems. In addition, the unit may be…

  16. 21 CFR 161.145 - Canned oysters.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Canned oysters. 161.145 Section 161.145 Food and... oysters. (a) Identity. (1) Canned oysters is the food prepared from one or any mixture of two or all of the forms of oysters specified in paragraph (a)(2) of this section, and a packing medium of water,...

  17. 21 CFR 161.145 - Canned oysters.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Canned oysters. 161.145 Section 161.145 Food and... oysters. (a) Identity. (1) Canned oysters is the food prepared from one or any mixture of two or all of the forms of oysters specified in paragraph (a)(2) of this section, and a packing medium of water,...

  18. 21 CFR 161.145 - Canned oysters.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Canned oysters. 161.145 Section 161.145 Food and... oysters. (a) Identity. (1) Canned oysters is the food prepared from one or any mixture of two or all of the forms of oysters specified in paragraph (a)(2) of this section, and a packing medium of water,...

  19. 21 CFR 161.145 - Canned oysters.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Canned oysters. 161.145 Section 161.145 Food and... oysters. (a) Identity. (1) Canned oysters is the food prepared from one or any mixture of two or all of the forms of oysters specified in paragraph (a)(2) of this section, and a packing medium of water,...

  20. 21 CFR 161.145 - Canned oysters.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Canned oysters. 161.145 Section 161.145 Food and... oysters. (a) Identity. (1) Canned oysters is the food prepared from one or any mixture of two or all of the forms of oysters specified in paragraph (a)(2) of this section, and a packing medium of water,...

  1. Detection of Sapovirus in oysters.

    PubMed

    Ueki, You; Shoji, Mika; Okimura, Yoko; Miyota, Yasuko; Masago, Yoshifumi; Oka, Tomoichiro; Katayama, Kazuhiko; Takeda, Naokazu; Noda, Mamoru; Miura, Takayuki; Sano, Daisuke; Omura, Tatsuo

    2010-08-01

    SaV sequences which are either genetically identical or similar were detected from oysters, feces from gastroenteritis patients, and domestic wastewater samples in geographically close areas. This is the first report of the detection of SaV in oysters which meet the legal requirements for raw consumption in Japan.

  2. Unprecedented restoration of a native oyster metapopulation.

    PubMed

    Schulte, David M; Burke, Russell P; Lipcius, Romuald N

    2009-08-28

    Native oyster species were once vital ecosystem engineers, but their populations have collapsed worldwide because of overfishing and habitat destruction. In 2004, we initiated a vast (35-hectare) field experiment by constructing native oyster reefs of three types (high-relief, low-relief, and unrestored) in nine protected sanctuaries throughout the Great Wicomico River in Virginia, United States. Upon sampling in 2007 and 2009, we found a thriving metapopulation comprising 185 million oysters of various age classes. Oyster density was fourfold greater on high-relief than on low-relief reefs, explaining the failure of past attempts. Juvenile recruitment and reef accretion correlated with oyster density, facilitating reef development and population persistence. This reestablished metapopulation is the largest of any native oyster worldwide and validates ecological restoration of native oyster species.

  3. Hyperspectral remote sensing of wild oyster reefs

    NASA Astrophysics Data System (ADS)

    Le Bris, Anthony; Rosa, Philippe; Lerouxel, Astrid; Cognie, Bruno; Gernez, Pierre; Launeau, Patrick; Robin, Marc; Barillé, Laurent

    2016-04-01

    The invasion of the wild oyster Crassostrea gigas along the western European Atlantic coast has generated changes in the structure and functioning of intertidal ecosystems. Considered as an invasive species and a trophic competitor of the cultivated conspecific oyster, it is now seen as a resource by oyster farmers following recurrent mass summer mortalities of oyster spat since 2008. Spatial distribution maps of wild oyster reefs are required by local authorities to help define management strategies. In this work, visible-near infrared (VNIR) hyperspectral and multispectral remote sensing was investigated to map two contrasted intertidal reef structures: clusters of vertical oysters building three-dimensional dense reefs in muddy areas and oysters growing horizontally creating large flat reefs in rocky areas. A spectral library, collected in situ for various conditions with an ASD spectroradiometer, was used to run Spectral Angle Mapper classifications on airborne data obtained with an HySpex sensor (160 spectral bands) and SPOT satellite HRG multispectral data (3 spectral bands). With HySpex spectral/spatial resolution, horizontal oysters in the rocky area were correctly classified but the detection was less efficient for vertical oysters in muddy areas. Poor results were obtained with the multispectral image and from spatially or spectrally degraded HySpex data, it was clear that the spectral resolution was more important than the spatial resolution. In fact, there was a systematic mud deposition on shells of vertical oyster reefs explaining the misclassification of 30% of pixels recognized as mud or microphytobenthos. Spatial distribution maps of oyster reefs were coupled with in situ biomass measurements to illustrate the interest of a remote sensing product to provide stock estimations of wild oyster reefs to be exploited by oyster producers. This work highlights the interest of developing remote sensing techniques for aquaculture applications in coastal

  4. Sediment bioassays with oyster larvae

    SciTech Connect

    Chapman, P.M.; Morgan, J.D.

    1983-10-01

    Tests with naturally-occurring sediments are rare and sediment testing methodology is not standardized. The authors present a simple methodology for undertaking sediment bioassays with oyster larvae, and present data from a recent study to prove the utility of this method.

  5. Composted oyster shell as lime fertilizer is more effective than fresh oyster shell.

    PubMed

    Lee, Young Han; Islam, Shah Md Asraful; Hong, Sun Joo; Cho, Kye Man; Math, Renukaradhya K; Heo, Jae Young; Kim, Hoon; Yun, Han Dae

    2010-01-01

    Physio-chemical changes in oyster shell were examined, and fresh and composted oyster shell meals were compared as lime fertilizers in soybean cultivation. Structural changes in oyster shell were observed by AFM and FE-SEM. We found that grains of the oyster shell surface became smoother and smaller over time. FT-IR analysis indicated the degradation of a chitin-like compound of oyster shell. In chemical analysis, pH (12.3+/-0.24), electrical conductivity (4.1+/-0.24 dS m(-1)), and alkaline powder (53.3+/-1.12%) were highest in commercial lime. Besides, pH was higher in composted oyster shell meal (9.9+/-0.53) than in fresh oyster shell meal (8.4+/-0.32). The highest organic matter (1.1+/-0.08%), NaCl (0.54+/-0.03%), and moisture (15.1+/-1.95%) contents were found in fresh oyster shell meal. A significant higher yield of soybean (1.33 t ha(-1)) was obtained by applying composted oyster shell meal (a 21% higher yield than with fresh oyster shell meal). Thus composting of oyster shell increases the utility of oyster shell as a liming material for crop cultivation.

  6. SETTLEMENT AND SURVIVAL OF THE OYSTER CRASSOSTREA VIRGINICA ON CREATED OYSTER REEF HABITATS IN CHESAPEAKE BAY

    EPA Science Inventory

    Efforts to restore the Eastern oyster (Crassostrea virginica) reef habitats in Chesapeake Bay typically begin with the placement of hard substrata to form three-dimensional mounds on the seabed to serve as a base for oyster recruitment and growth. A shortage of oyster shell for ...

  7. High pressure inactivation of HAV within oysters: comparison of shucked oysters with whole in shell meats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High pressure inactivation of hepatitis A virus (HAV) within oysters bioaccumulated under simulated natural conditions to levels >106 PFU/oyster has been evaluated. Five min treatments at 20C were administered at 350, 375, and 400 MegaPascals (MPa). Shucked and whole-in-shell oysters were directly...

  8. Mapping Oyster Reef Habitats in Mobile Bay

    NASA Technical Reports Server (NTRS)

    Bolte, Danielle

    2011-01-01

    Oyster reefs around the world are declining rapidly, and although they haven t received as much attention as coral reefs, they are just as important to their local ecosystems and economies. Oyster reefs provide habitats for many species of fish, invertebrates, and crustaceans, as well as the next generations of oysters. Oysters are also harvested from many of these reefs and are an important segment of many local economies, including that of Mobile Bay, where oysters rank in the top five commercial marine species both by landed weight and by dollar value. Although the remaining Mobile Bay oyster reefs are some of the least degraded in the world, projected climate change could have dramatic effects on the health of these important ecosystems. The viability of oyster reefs depends on water depth and temperature, appropriate pH and salinity levels, and the amount of dissolved oxygen in the water. Projected increases in sea level, changes in precipitation and runoff patterns, and changes in pH resulting from increases in the amount of carbon dioxide dissolved in the oceans could all affect the viability of oyster reefs in the future. Human activities such as dredging and unsustainable harvesting practices are also adversely impacting the oyster reefs. Fortunately, several projects are already under way to help rebuild or support existing or previously existing oyster reefs. The success of these projects will depend on the local effects of climate change on the current and potential habitats and man s ability to recognize and halt unsustainable harvesting practices. As the extent and health of the reefs changes, it will have impacts on the Mobile Bay ecosystem and economy, changing the resources available to the people who live there and to the rest of the country, since Mobile Bay is an important national source of seafood. This project identified potential climate change impacts on the oyster reefs of Mobile Bay, including the possible addition of newly viable

  9. 7 CFR 701.54 - Oysters.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Oysters. 701.54 Section 701.54 Agriculture Regulations... ADMINISTERED UNDER THIS PART § 701.54 Oysters. (a) Notwithstanding § 701.5(b), but otherwise subject to the... be made available under this section for the eligible cost of refurbishing public or private...

  10. Uptake of cadmium from Pacific oysters (Crassostrea gigas) in British Columbia oyster growers

    SciTech Connect

    Copes, Ray Clark, Nina Annika; Rideout, Karen; Palaty, Jan; Teschke, Kay

    2008-06-15

    Background: Pacific oysters along the North American coast from Washington to Alaska contain concentrations of cadmium (Cd) that are high by comparison with Atlantic oysters, frequently exceeding 2 {mu}g/g wet weight, but it is unclear whether this Cd is absorbed by consumers. Objectives: To determine the effect of oyster consumption on Cd in blood and urine among a group with high oyster consumption. Methods: Sixty-one non-smoking oyster growers and family members with a mean age of 47.3{+-}7.6 years (range 33-64) were interviewed by telephone to assess their oyster consumption and other sources of Cd exposure at present and 5 years prior to the start of oyster farming. Their blood and urine Cd concentrations were measured. Results: The geometric mean Cd concentration in blood was 0.83 {mu}g/L and in urine was 0.76 {mu}g/g creatinine. Thirty-six percent of participants had urinary Cd levels above 1 {mu}g/g creatinine and 5% were above 2 {mu}g/g creatinine. Recent (last 12 months) and long-term oyster consumptions were positive predictors of blood Cd but did not directly predict urinary Cd. The optimal model for predicting the variance in blood Cd included recent intake of oyster-derived Cd, serum iron concentration and recent ketchup consumption (R{sup 2}=0.34, p=0.00004), with the latter two variables showing a protective effect. The factors found to predict urinary Cd were blood Cd concentration and duration of oyster farming. A rise in blood Cd was observed after 12 years of farming oysters, likely caused by higher consumption of oysters during this period. Conclusions: Oyster-derived Cd is bioavailable and affects body stores of the metal.

  11. How long does oyster shell last on an oyster reef?

    NASA Astrophysics Data System (ADS)

    Powell, Eric N.; Kraeuter, John N.; Ashton-Alcox, Kathryn A.

    2006-09-01

    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.

  12. Noroviruses in oysters from local markets and oyster farms in southern Thailand.

    PubMed

    Kittigul, Leera; Pombubpa, Kannika; Sukonthalux, Suntharee; Rattanatham, Tippawan; Utrarachkij, Fuangfa

    2011-01-01

    One hundred and eighteen oyster samples collected from local markets and oyster farms in southern Thailand were examined for noroviruses (NoVs) and bacterial indicators of fecal contamination (fecal coliforms and Escherichia coli). Using a virus concentration procedure followed by RT-nested PCR, NoVs were detected in 38% of the samples. Oysters collected from oyster farms were found with NoVs at a higher detection rate (25/53 samples) than oysters from local markets (20/65 samples). Of the 45 NoV-positive oyster samples, 67% belonged to NoV genogroup I (GI), 15% to GII, and 18% to both GI and GII. DNA sequencing showed that 2 NoVs belonged to NoV GI-2 genotype. Fecal coliforms in NoV-positive oyster samples were in the range of < 3.0 to 1.5 x 10(4) most probable number (MPN)/g and 33% of NoV-positive oyster samples contained fecal coliforms within the standard acceptable level of raw shellfish (< 20 MPN/g). E. coli was found in the range of < 3.0 to 1.5 x 10(4) MPN/g and 9% of NoV-positive oyster samples were within acceptable levels of E. coli contamination (< 3 MPN/g). These findings indicate that NoV contamination in oysters obtained from both markets and oyster farms might pose a potential risk of acute gastroenteritis associated with raw oyster consumption. Examination for both fecal bacterial indicators and enteric viruses should be conducted for microbiological food safety of shellfish.

  13. Calculation of Oyster Benefits with a Bioenergetics Model of the Virginia Oyster

    DTIC Science & Technology

    2014-11-01

    tissue, shell, and reproductive material. The bioenergetics model is coupled to an oyster benefits module. The calculation of benefits is based on...individual oyster (Figure 1). These are shell, soft tissue, and reproductive material. The oysters filter overlying water continuously, although the rate...is a constant fraction of the energy expended in feeding. Basal metabolism proceeds at a rate independent of activity. Reproductive material is

  14. Norovirus contamination on French marketed oysters.

    PubMed

    Schaeffer, Julien; Le Saux, Jean-Claude; Lora, Monica; Atmar, Robert L; Le Guyader, Françoise S

    2013-09-02

    Contaminated shellfish have been implicated in gastroenteritis outbreaks in different countries. As no regulation has been set up yet regarding viral contamination of food, very few data are available on the prevalence of contaminated products on the market. This study presents data obtained from oysters collected on the French market in one producing area over a 16 month period of time. Noroviruses were detected in 9% of samples with a seasonal impact and influence of climatic events. Contamination levels were low and, surprisingly, oysters sampled directly from the producer were found to have less contamination than oysters from supermarkets.

  15. Norovirus contamination on French marketed oysters

    PubMed Central

    Schaeffer, Julien; Le Saux, Jean-Claude; Lora, Monica; Atmar, Robert L.; Le Guyader, Françoise S.

    2014-01-01

    Contaminated shellfish have been implicated in gastroenteritis outbreaks in different countries. As no regulation has been set up yet regarding viral contamination of food, very few data are available on the prevalence of contaminated products on the market. This study presents data obtained from oysters collected on the French market in one producing area over a 16 month period of time. Noroviruses were detected in 9% of samples with a seasonal impact and influence of climatic events. Contamination levels were low and, surprisingly, oysters sampled directly from the producer were found to have less contamination than oysters from supermarkets. PMID:23973835

  16. ACTIVATION OF OYSTER DEFENSES BY ENVIRONMENTAL CONTAMINANTS

    EPA Science Inventory

    Four field studies performed on eastern oysters Crassostrea virginica support a hypothesis that Cu, Zn, and perhaps butyltins and polycyclic aromatic hydrocarbons (PAH) can stimulate hemopoiesis, hemocyte locomotion and hemocyte bactericidal capacity. The first study found circul...

  17. Survival of Salmonella Newport in oysters.

    PubMed

    Morrison, Christopher M; Armstrong, Alexandra E; Evans, Sanford; Mild, Rita M; Langdon, Christopher J; Joens, Lynn A

    2011-08-02

    Salmonella enterica is the leading cause of laboratory-confirmed foodborne illness in the United States and raw shellfish consumption is a commonly implicated source of gastrointestinal pathogens. A 2005 epidemiological study done in our laboratory by Brands et al., showed that oysters in the United States are contaminated with Salmonella, and in particular, a specific strain of the Newport serovar. This work sought to further investigate the host-microbe interactions between Salmonella Newport and oysters. A procedure was developed to reliably and repeatedly expose oysters to enteric bacteria and quantify the subsequent levels of bacterial survival. The results show that 10 days after an exposure to Salmonella Newport, an average concentration of 3.7 × 10(3)CFU/g remains within the oyster meat, and even after 60 days there still can be more than 10(2)CFU/g remaining. However, the strain of Newport that predominated in the market survey done by Brands et al. does not survive within oysters or the estuarine environment better than any other strains of Salmonella we tested. Using this same methodology, we compared Salmonella Newport's ability to survive within oysters to a non-pathogenic strain of E. coli and found that after 10 days the concentration of Salmonella was 200-times greater than that of E. coli. We also compared those same strains of Salmonella and E. coli in a depuration process to determine if a constant 120 L/h flux of clean seawater could significantly reduce the concentration of bacteria within oysters and found that after 3 days the oysters retained over 10(4)CFU/g of Salmonella while the oysters exposed to the non-pathogenic strain of E. coli contained 100-times less bacteria. Overall, the results of this study demonstrate that any of the clinically relevant serovars of Salmonella can survive within oysters for significant periods of time after just one exposure event. Based on the drastic differences in survivability between Salmonella and a non

  18. Immunochromatographic assay of cadmium levels in oysters.

    PubMed

    Nishi, Kosuke; Kim, In-Hae; Itai, Takaaki; Sugahara, Takuya; Takeyama, Haruko; Ohkawa, Hideo

    2012-08-15

    Oysters are one of foodstuffs containing a relatively high amount of cadmium. Here we report on establishment of an immunochromatographic assay (ICA) method of cadmium levels in oysters. Cadmium was extracted with 0.l mol L(-1) HCl from oysters and cleaned up from other metals by the use of an anion-exchange column. The behavior of five metals Mn, Fe, Cu, Zn, and Cd was monitored at each step of extraction and clean-up procedure for the ICA method in an inductively coupled plasma-mass spectrometry (ICP-MS) analysis. The results revealed that a simple extraction method with the HCl solution was efficient enough to extract almost all of cadmium from oysters. Clean-up with an anion-exchange column presented almost no loss of cadmium adsorbed on the column and an efficient removal of metals other than cadmium. When a spiked recovery test was performed in the ICA method, the recovery ranged from 98% to 112% with relative standard deviations between 5.9% and 9.2%. The measured values of cadmium in various oyster samples in the ICA method were favorably correlated with those in ICP-MS analysis (r(2)=0.97). Overall results indicate that the ICA method established in the present study is an adequate and reliable detection method for cadmium levels in oysters.

  19. Oyster Reef Communities in the Chesapeake Bay: A Brief Primer. VORTEX: Virginia's Oyster Reef Teaching EXperience.

    ERIC Educational Resources Information Center

    Harding, Juliana M.; Mann, Roger; Clark, Vicki P.

    This document introduces Virginia's Oyster Reef Teaching EXperience (VORTEX), which is an interdisciplinary program focusing on the importance of oyster reef communities in the Chesapeake Bay ecosystem. The VORTEX program uses field and laboratory experience supported by multimedia instruction. This document presents an overview on the biology of…

  20. Densoviruses in oyster Crassostrea ariakensis.

    PubMed

    Kang, Yan-Jun; Huang, Wei; Zhao, A-Li; Lai, Dan-Dan; Shao, Lin; Shen, Yan-Qin; Deng, Xutao; Delwart, Eric; Zhang, Wen

    2017-03-24

    Densoviruses have short ssDNA genomes and mainly infect arthropods. To characterize viral nucleic acid in shellfish, oysters (Crassostrea ariakensis) were analyzed using viral metagenomics. Two large de novo assembled contigs, CaaDV1 and CaaDV2, consisting of nearly complete densovirus genomes (5860 nucleotides (nt) and 4034 nt) with two major ambisense protein coding regions were identified. Several potential non-structural proteins and capsid proteins were encoded by these genomes, but these were divergent from the existing densoviral species. The NS1 protein of the two CaaDVs shared 43.3%~61.5% amino acid identities with the sea star-associated densovirus and cherax quadricarinatus densovirus, with the four species clustering by phylogenetic analysis. This is the first report of densovirus detection in shellfish, increasing the potential host range of densoviruses and the genetic diversity of the genus Ambidensovirus.

  1. Antiviral active peptide from oyster

    NASA Astrophysics Data System (ADS)

    Zeng, Mingyong; Cui, Wenxuan; Zhao, Yuanhui; Liu, Zunying; Dong, Shiyuan; Guo, Yao

    2008-08-01

    An active peptide against herpes virus was isolated from the enzymic hydrolysate of oyster ( Crassostrea gigas) and purified with the definite direction hydrolysis technique in the order of alcalase and bromelin. The hydrolysate was fractioned into four ranges of molecular weight (>10 kDa, 10 5 kDa, 5 1 kDa and <1 kDa) using ultrafiltration membranes and dialysis. The fraction of 10 5 kDa was purified using consecutive chromatographic methods including DEAE Sephadex A-25 column, Sephadex G-25 column, and high performance liquid chromatogram (HPLC) by activity-guided isolation. The antiviral effect of the obtained peptide on herpetic virus was investigated in Vero cells by observing cytopathic effect (CPE). The result shows that the peptide has high inhibitory activity on herpetic virus.

  2. BOILER, LOCATED IN BACK ROOM OF OYSTER SHUCKING BUILDING. STEAM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    BOILER, LOCATED IN BACK ROOM OF OYSTER SHUCKING BUILDING. STEAM WAS USED IN OYSTER PROCESSING, FOR EXAMPLE IN STERILIZING EQUIPMENT. - F. & H. Benning Company, 1014 Benning Road, Galesville, Anne Arundel County, MD

  3. Oyster shell conveyor used to lift shells from the dock ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Oyster shell conveyor used to lift shells from the dock into the receiving room housed in the 1965 concrete block addition. - J.C. Lore Oyster House, 14430 Solomons Island Road, Solomons, Calvert County, MD

  4. INFLUENCE OF ALTERED FRESHWATER FLOWS ON EASTERN OYSTERS

    EPA Science Inventory

    Abstract for National Shellfisheries Association

    Eastern oysters Crassostrea virginica are prominent in Gulf of Mexico estuaries. Valued both commercially and ecologically, oyster populations are threatened by human activity, including dredging, harvesting, and upstream al...

  5. Trace metals in Gulf of Mexico oysters.

    PubMed

    Presley, B J; Taylor, R J; Boothe, P N

    1990-11-01

    Oysters (Crassostrea virginica) from 50 to 69 locations (sites) along the Gulf of Mexico coastline, collected annually in 1986, 1987 and 1988, have been analyzed for 13 trace metals, including most of the metals of concern from an environmental quality perspective. Essentially the entire U.S. Gulf coastline was sampled, from far south Texas to far south Florida. Pooled samples of 20 oysters from three different stations at each site were analyzed by atomic absorption spectrophotometry. The concentrations found were generally less than or equal to literature values from other parts of the world thought to be uncontaminated by anthropogenic trace metal inputs. A few sites did, however, show apparent trace metal pollution and other sites gave anomalous values that cannot readily be explained by either known anthropogenic or natural causes. The range of values for the overall data set (maximum/minimum) varied from 15-fold for Mn to 624-fold for Pb, whereas the coefficient of variation (standard deviation/mean) was generally in the 50-60% range for most metals. Variations were much greater between stations than between years at a given station. Enrichments usually occurred in suites of three to four elements with Ag, Cd, Cu and Zn being the most common suite, thus several strong inter-element correlations were found. There was, however, little correlation between metal levels in oysters and in sediments from the collection sites even when sediment data were rationed to Al (sediment data are not given here). There was likewise little correlation between oyster metal levels and size, sex or reproductive stage of the oysters (data given elsewhere). Geographically, appreciably elevated (greater than 3 times average) metal levels were generally restricted to single sites within bays or estuaries, implying local control. On the other hand, regionally, Ag, Cd and Se levels were somewhat higher in Texas oysters than in those from Florida, whereas the reverse was true for As and

  6. Directly measured denitrification reveals oyster aquaculture and restored oyster reefs remove nitrogen at comparable high rates

    EPA Science Inventory

    Coastal systems are increasingly impacted by over-enrichment of nutrients, which has cascading effects for ecosystem functioning. Oyster restoration and aquaculture are both hypothesized to mitigate excessive nitrogen (N) loads via benthic denitrification (DNF). However, this has...

  7. Eating oysters without risk of vibriosis: application of a bacteriophage against Vibrio parahaemolyticus in oysters.

    PubMed

    Jun, Jin Woo; Kim, Hyoun Joong; Yun, Sae Kil; Chai, Ji Young; Park, Se Chang

    2014-10-01

    Vibrio parahaemolyticus is a major cause of foodborne illness and related with the consumption of raw contaminated seafood, especially oysters. To evaluate the effectiveness of various applications of a bacteriophage (phage), pVp-1, against a multiple-antibiotic-resistant V. parahaemolyticus pandemic strain (CRS 09-17), we designed artificial contamination models that are most likely to be encountered during oyster processing. When live oysters were treated with bath immersion with pVp-1 after CRS 09-17 challenge, the growth of bacterial strain was significantly reduced. After 72h of phage application with bath immersion, bacterial growth reduction was observed to be 8.9×10(6)CFU/ml (control group) to 1.4×10CFU/ml (treatment group). When pVp-1 was surface-applied on the flesh of oysters after CRS 09-17 inoculation, bacterial growth was properly inhibited. After 12h of phage application on the surface of oysters, bacterial growth inhibition was revealed to be 1.44×10(6)CFU/ml (control group) to 1.94CFU/ml (treatment group). This is the first report, to the best of our knowledge, of oyster surface-application of a phage against a multiple-antibiotic-resistant V. parahaemolyticus pandemic strain, and our successful phage application to various situations emphasizes the potential use of the phage to avoid V. parahaemolyticus infection from aquaculture to consumption.

  8. Inactivation of murine norovirus and feline calicivirus during oyster fermentation.

    PubMed

    Seo, Dong Joo; Lee, Min Hwa; Seo, Jina; Ha, Sang-Do; Choi, Changsun

    2014-12-01

    Fermented seafood is popular in Asian countries. This study examined the survival of feline calicivirus (FCV) and murine norovirus (MNV) during oyster fermentation. Oysters spiked with FCV and MNV were fermented with 5% or 10% salt at 18 °C for 15 days, and MNV and FCV titers, lactic acid bacteria (LAB) populations, pH, and enzymatic activity were measured at 0, 1, 3, 5, 7, 10, and 15 days post-fermentation (DPF). Reductions in MNV and FCV were greater in 5% NaCl-supplemented oysters than in 10% NaCl-supplemented oysters. In 5% NaCl oysters, MNV and FCV titers significantly decreased by 1.60 log and 3.01 log, respectively, at 15 DPF. Populations of LAB increased from 3.62 log10 colony-forming units/g at 0 DPF to 8.77 log10 colony-forming units/g at 15 DPF during oyster fermentation supplemented with 5% NaCl supplementation, and the pH decreased gradually from 5.38 at 0 DPF to 4.17 at 15 DPF. During oyster fermentation, α-amylase, proteinase, and lipase were produced at higher levels in 5% salted oysters than in 10% salted oysters (P < 0.01). We concluded that many of the antimicrobial factors produced in fermented oysters could contribute to a reduction in foodborne viruses.

  9. Shape analysis for an automatic oyster grading system

    NASA Astrophysics Data System (ADS)

    Lee, Dah-Jye; Xu, Xiaoqian; Lane, Robert M.; Zhan, Pengcheng

    2004-12-01

    An overview of the oyster industry in the U. S. with emphasis in Virginia shows oyster grading occurs at harvest, wholesale and processing markets. Currently whole oysters, also called shellstock, are graded manually by screening and sorting based on diameter or weight. The majority of oysters harvested for the processing industry are divided into three to four main grades: small, medium, large, and selects. We have developed a shape analysis method for an automatic oyster grading system. The system first detects and removes poor quality oysters such as banana shape, broken shell, and irregular shapes. Good quality oysters move further into grades of small, medium and large. The contours of the oysters are extracted for shape analysis. Banana shape and broken shell have a specific shape flaw (or difference) compared to the ones with good quality. Global shape properties such as compactness, roughness, and elongation are suitable and useful to measure the shape flaw. Image projection area or length of the major axis measured as global properties for sizing. Incorporating a machine vision system for grading, sorting and counting oysters supports reduced operating costs. The savings produced from reducing labor, increasing accuracy in size, grade and count and providing real time accurate data for accounting and billing would contribute to the profit of the oysters industry.

  10. Predation by native brown shrimp on invasive Pacific oyster spat

    NASA Astrophysics Data System (ADS)

    Weerman, E. J.; Eriksson, B. K.; Olff, H.; van der Heide, T.

    2014-01-01

    In the last decades, the invasive Pacific oyster (Crassostrea gigas) increased dramatically in the Wadden Sea. One of the driving mechanisms for the success of the Pacific oyster could be a relatively low predation pressure by epibenthic predators and shore birds on oyster spat. Nevertheless, observations and experiments on predation rates on early life-stages of the Pacific oyster are rare. Therefore, we examined predation rates of brown shrimps on Pacific oyster spat in a number of laboratory experiments. Our results demonstrate that spat of Pacific oysters are most susceptible to predation by brown shrimps (Crangon crangon) in the first days after settlement, when attachment to the substrate (unglazed tiles in our study) is still absent or weak. At this stage the shell length of oyster spat is around ~ 300 μm, and around 50% of the individuals in the experiment were consumed in the two hour trials. Predation rates decreased rapidly as the spat grew larger and reached zero within 10 days after settlement of the spat (shell length > 700 μm). Additional experiments revealed that the attachment of oysters is probably limiting predation by brown shrimps rather than the size of the spat. This indicates that Pacific oyster spat may limit predation loss faster compared to native bivalves, which commonly depend on size to reduce predation rates. Overall, our results suggest that the invasive success of Pacific oysters may in part be explained by relatively low predation rates throughout their life stages.

  11. Use of oysters to mitigate eutrophication in coastal waters

    NASA Astrophysics Data System (ADS)

    Kellogg, M. Lisa; Smyth, Ashley R.; Luckenbach, Mark W.; Carmichael, Ruth H.; Brown, Bonnie L.; Cornwell, Jeffrey C.; Piehler, Michael F.; Owens, Michael S.; Dalrymple, D. Joseph; Higgins, Colleen B.

    2014-12-01

    Enhancing populations of suspension feeding bivalves, particularly the eastern oyster, Crassostrea virginica, has been proposed as a means of mitigating eutrophication in coastal waters. Review of studies evaluating the effects of C. virginica on nitrogen (N) cycling found that oysters can have effects on water quality that vary by orders of magnitude among sites, seasons, and growing condition (e.g., oyster reefs, aquaculture). Nitrogen contained in phytoplankton consumed by oysters may be returned to the water column, assimilated into oyster tissue and shell, buried in the sediments, or returned to the atmosphere as dinitrogen gas, primarily via denitrification. Accurately quantifying oyster-related N removal requires detailed knowledge of these primary fates of N in coastal waters. A review of existing data demonstrated that the current state of knowledge is incomplete in many respects. Nitrogen assimilated into oyster tissue and shell per gram of dry weight was generally similar across sites and in oysters growing on reefs compared to aquaculture. Data on long-term burial of N associated with oyster reefs or aquaculture are lacking. When compared to suitable reference sites, denitrification rates were not consistently enhanced. Depending on environmental and oyster growing conditions, changes in denitrification rates varied by orders of magnitude among studies and did not always occur. Oyster aquaculture rarely enhanced denitrification. Unharvested oyster reefs frequently enhanced denitrification rates. Incorporating oysters into nutrient reduction strategies will require filling gaps in existing data to determine the extent to which relationships between N removal and environmental and/or growing conditions can be generalized.

  12. Oyster School Stands the Test of Time.

    ERIC Educational Resources Information Center

    Fern, Veronica

    1995-01-01

    Describes Oyster Elementary School's award-winning two-way bilingual (Spanish-English) program. The school's success has been maintained by strong parent and community support, high academic standards, and ongoing professional development efforts. However, cultural, generational, and socioeconomic differences among staff, students, and parents…

  13. Drywell corrosion stopped at Oyster Creek

    SciTech Connect

    Lipford, B.L. ); Flynn, J.C.

    1993-11-01

    This article describes the detection of corrosion on the drywell containment vessel of Oyster Creek Nuclear Plant and the application of a protective coating to repair the drywell. The topics of the article include drywell design features, identification of the problem, initial action, drywell corrosion, failure of cathodic protection, long-term repair, and repair results.

  14. INORGANIC ELEMENTS AND DISTRIBUTION OF EASTERN OYSTERS.

    EPA Science Inventory

    Fisher, William S. In press. Inorganic Elements and Distribution of Eastern Oysters (Abstract). To be presented at the 96th Annual Meeting (Aquaculture 2004) of the National Shellfisheries Association, 1-5 March 2004, Honolulu, HI. 1 p. (ERL,GB R962).

    For over a century w...

  15. A microbial spoilage profile of half shell Pacific oysters (Crassostrea gigas) and Sydney rock oysters (Saccostrea glomerata).

    PubMed

    Madigan, Thomas L; Bott, Nathan J; Torok, Valeria A; Percy, Nigel J; Carragher, John F; de Barros Lopes, Miguel A; Kiermeier, Andreas

    2014-04-01

    This study aimed to assess bacterial spoilage of half shell Pacific and Sydney rock oysters during storage using microbial culture and 16S rRNA pyrosequencing. Odour and pH of oyster meats were also investigated. Estimation of microbiological counts by microbial culture highlighted growth of psychrotrophic bacteria. During storage, odour scores (a score describing deterioration of fresh odours where a score of 1 is fresh and 4 is completely spoiled) increased from 1.0 to 3.0 for Pacific oysters and from 1.3 to 3.4 for Sydney rock oysters. pH results obtained for both species fluctuated during storage (range 6.28-6.73) with an overall increase at end of storage. Pyrosequencing revealed that the majority of bacteria at Day 0 represented taxa from amongst the Proteobacteria, Tenericutes and Spirochaetes that have not been cultured and systematically described. During storage, Proteobacteria became abundant with Pseudoalteromonas and Vibrio found to be dominant in both oyster species at Day 7. Analysis of the pyrosequencing data showed significant differences in bacterial profiles between oyster species and storage time (both P = 0.001). As oysters spoiled, bacterial profiles between oyster species became more similar indicating a common spoilage profile. Data presented here provides detailed insight into the changing bacterial profile of shucked oysters during storage and has identified two genera, Pseudoalteromonas and Vibrio, as being important in spoilage of shucked oysters.

  16. OYSTER POPULATUION ESTIMATION IN SUPPORT OF THE TEN-YEAR GOAL FOR OYSTER RESOTRATION IN THE CHESAPEAKE BAY: DEVELOPING STRATEGIES FOR RESTORING AND MANAGING THE EASTERN OYSTER

    EPA Science Inventory

    Mann, Roger, Steve Jordan, Gary Smith, Kennedy Paynter, James Wesson, Mary Christman, Jessica Vanisko, Juliana Harding, Kelly Greenhawk and Melissa Southworth. 2003. Oyster Population Estimation in Support of the Ten-Year Goal for Oyster Restoration in the Chesapeake Bay: Develop...

  17. From artificial structures to self-sustaining oyster reefs

    NASA Astrophysics Data System (ADS)

    Walles, Brenda; Troost, Karin; van den Ende, Douwe; Nieuwhof, Sil; Smaal, Aad C.; Ysebaert, Tom

    2016-02-01

    Coastal ecosystems are increasingly recognized as essential elements within coastal defence schemes and coastal adaptation. The capacity of coastal ecosystems, like marshes and oyster reefs, to maintain their own habitat and grow with sea-level rise via biophysical feedbacks is seen as an important advantage of such systems compared to man-made hard engineering structures. Providing a suitable substrate for oysters to settle on offers a kick-start for establishment at places where they were lost or are desirable for coastal protection. Accumulation of shell material, through recruitment and growth, is essential to the maintenance of oyster reefs as it provides substrate for new generations (positive feedback loop), forming a self-sustainable structure. Insight in establishment, survival and growth thresholds and knowledge about the population dynamics are necessary to successfully implement oyster reefs in coastal defence schemes. The aim of this paper is to investigate whether artificial Pacific oyster reefs develop into self-sustaining oyster reefs that contribute to coastal protection. Reef development was investigated by studying recruitment, survival and growth rates of oysters on artificial oyster reefs in comparison with nearby natural Pacific oyster reefs. The artificial reef structure successfully offered substrate for settlement of oysters and therefore stimulated reef formation. Reef development, however, was hampered by local sedimentation and increasing tidal emersion. Tidal emersion is an important factor that can be used to predict where artificial oyster reefs have the potential to develop into self-sustaining reefs that could contribute to coastal protection, but it is also a limiting factor in using oyster reefs for coastal protection.

  18. Immune and stress responses in oysters with insights on adaptation.

    PubMed

    Guo, Ximing; He, Yan; Zhang, Linlin; Lelong, Christophe; Jouaux, Aude

    2015-09-01

    Oysters are representative bivalve molluscs that are widely distributed in world oceans. As successful colonizers of estuaries and intertidal zones, oysters are remarkably resilient against harsh environmental conditions including wide fluctuations in temperature and salinity as well as prolonged air exposure. Oysters have no adaptive immunity but can thrive in microbe-rich estuaries as filter-feeders. These unique adaptations make oysters interesting models to study the evolution of host-defense systems. Recent advances in genomic studies including sequencing of the oyster genome have provided insights into oyster's immune and stress responses underlying their amazing resilience. Studies show that the oyster genomes are highly polymorphic and complex, which may be key to their resilience. The oyster genome has a large gene repertoire that is enriched for immune and stress response genes. Thousands of genes are involved in oyster's immune and stress responses, through complex interactions, with many gene families expanded showing high sequence, structural and functional diversity. The high diversity of immune receptors and effectors may provide oysters with enhanced specificity in immune recognition and response to cope with diverse pathogens in the absence of adaptive immunity. Some members of expanded immune gene families have diverged to function at different temperatures and salinities or assumed new roles in abiotic stress response. Most canonical innate immunity pathways are conserved in oysters and supported by a large number of diverse and often novel genes. The great diversity in immune and stress response genes exhibited by expanded gene families as well as high sequence and structural polymorphisms may be central to oyster's adaptation to highly stressful and widely changing environments.

  19. Bactericidal effects of wine on Vibrio parahaemolyticus in oysters.

    PubMed

    Liu, Chengchu; Chen, Ruiying; Su, Yi-Cheng

    2006-08-01

    The bactericidal effects of wines on Vibrio parahaemolyticus in oysters were studied to evaluate potential inactivation of V. parahaemolyticus in contaminated oysters by wine consumption. Shucked whole oyster and oyster meat homogenate were inoculated with V. parahaemolyticus and mixed with red or white wine. Survivals of V. parahaemolyticus in inoculated oysters were determined at 7 and 25 degrees C. Populations of V. parahaemolyticus in inoculated whole oysters (5.52 log most probable number [MPN] per g) decreased slightly to 4.90 log MPN/g (a 0.62-log reduction) after 24 h at 7 degrees C but increased to 7.37 log MPN/g over the same period at 25 degrees C. However, the populations in wine-treated whole oysters decreased by >1.7 and >1.9 log MPN/g after 24 h at 7 and 25 degrees C, respectively. Both red and white wines were more effective in inactivating V. parahaemolyticus in oyster meat homogenate than in whole oyster. Populations of V. parahaemolyticus in oyster meat homogenate (7.8 x 10(3) MPN/g) decreased rapidly to nondetectable levels (< 3 MPN/g) after 30 min of mixing with wine at 25 degrees C (a 3.89-log MPN/g reduction). These results suggest that chewing oysters before swallowing when eating raw oysters may result in greater inactivation of V. parahaemolyticus if wine is consumed. More studies are needed to determine the bactericidal effects of wine on V. parahaemolyticus in the complicated stomach environment.

  20. Understanding transplanted oysters as bioindicators of trace organic contamination

    SciTech Connect

    Sericano, J.L.; Wade, T.L.

    1995-12-31

    This study was designed to examine the uptake and depuration of polynuclear aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) by transplanted oysters (Crassostrea virginica) under field conditions in Galveston Bay, Texas. Oyster were transplanted from a relative pristine area to a highly contaminated location near the Houston Ship Channel. During 48 days, the concentrations of individual PAHs and PCBs in transplanted oysters were compared to the levels found in indigenous oysters. Four and fie-ring PAHs were rapidly bioaccumulated by transplanted oysters and apparent equilibrium concentrations were reached after 20 to 30 days of exposure to the new environmental conditions. One month after the experiment started, no statistically significant differences were observed in the concentration of individual PAHs or the distributions of PAHs grouped by ring number between indigenous and transplanted oysters. PCBs were also bioconcentrated during the uptake period although the final total concentrations were lower than those measured in indigenous oysters. Low molecular weight PCBs were rapidly taken up by transplanted oysters and reached an equilibrium plateau at the end of the seven-week exposure period. In contrast, the uptake of high molecular weight PCBs was significantly slower and a final equilibrium with environmental levels was not observed. Oysters can be useful tools in biomonitoring studies but results differ for different trace organic contaminants. While PAH and low molecular weight PCB concentrations reach a steady-state within about one month, high molecular weight PCB congeners require a much longer period of time, i.e. over 6 months.

  1. Temperature-dependent stress response in oysters, Crassostrea virginica: pollution reduces temperature tolerance in oysters.

    PubMed

    Lannig, Gisela; Flores, Jason F; Sokolova, Inna M

    2006-09-12

    Combined effects of temperature and a toxic metal, cadmium (Cd), on energy metabolism were studied in a model marine bivalve, the eastern oyster Crassostrea virginica, acclimated at 20, 24 and 28 degrees C and exposed to 50microgl(-1) of Cd. Both increasing temperature and Cd exposure led to a rise in standard metabolic rates, and combined stressors appeared to override the capability for aerobic energy production resulting in impaired stress tolerance. Oysters exposed to elevated temperature but not Cd showed no significant change in condition, survival rate and lipid peroxidation, whereas those exposed to both Cd and temperature stress suffered high mortality accompanied by low condition index and elevated lipid peroxidation. Furthermore, RNA/DNA ratios indicative of protein synthesis rate, and levels of glutathione, which is involved in metal detoxification, increased in Cd-exposed oysters at 20 degrees C but not at 28 degrees C. Implications of the synergism between elevated temperatures and cadmium stress on energy metabolism of oysters are discussed in the light of the potential effects of climate change on oyster populations in polluted areas.

  2. Non-indigenous predators threaten ecosystem engineers: Interactive effects of green crab and oyster size on American oyster mortality.

    PubMed

    Pickering, Tyler R; Poirier, Luke A; Barrett, Timothy J; McKenna, Shawn; Davidson, Jeff; Quijón, Pedro A

    2017-03-12

    Non-indigenous green crabs (Carcinus maenas) are emerging as important predators of autogenic engineers like American oysters (Crassostrea virginica) throughout the eastern seaboard of Canada and the United States. To document the spreading distribution of green crabs, we carried out surveys in seven sites of Prince Edward Island during three fall seasons. To assess the potential impact of green crabs on oyster mortality in relation to predator and prey size, we conducted multiple predator-prey manipulations in the field and laboratory. The surveys confirmed an ongoing green crab spread into new productive oyster habitats while rapidly increasing in numbers in areas where crabs had established already. The experiments measured mortality rates on four sizes of oysters exposed to three sizes of crab, and lasted 3-5 days. The outcomes of experiments conducted in Vexar(®) bags, laboratory tanks and field cages were consistent and were heavily dependent on both crab size and oyster size: while little predation occurred on large oysters, large and medium green crabs preyed heavily on small sizes. Oysters reached a refuge within the 35-55 mm shell length range; below that range, oysters suffered high mortality due to green crab predation and thus require management measures to enhance their survival. These results are most directly applicable to aquaculture operations and restoration initiatives but have implications for oyster sustainability.

  3. 76 FR 79227 - Exemption Request Submitted by Oyster Creek Nuclear Generating Station; Exelon Generation Company...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-21

    ... COMMISSION Exemption Request Submitted by Oyster Creek Nuclear Generating Station; Exelon Generation Company... Generation Company, LLC (the licensee), for operation of the Oyster Creek Nuclear Generating Station (Oyster... for Oyster Creek and NUREG-1437, Vol. 1, Supplement 28, ``Generic Environmental Impact Statement...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  5. Seasonal dynamics and diversity of bacteria in retail oyster tissues.

    PubMed

    Wang, Dapeng; Zhang, Qian; Cui, Yan; Shi, Xianming

    2014-03-03

    Oysters are one of the important vehicles for the transfer of foodborne pathogens. It was reported that bacteria could be bio-accumulated mainly in the gills and digestive glands. In artificially treated oysters, bacterial communities have been investigated by culture-independent methods after harvest. However, little information is available on the seasonal dynamics of bacterial accumulation in retail oyster tissues. In this study, retail oysters were collected from local market in different seasons. The seasonal dynamics and diversity of bacteria in oyster tissues, including the gills, digestive glands and residual tissues, were analyzed by denaturing gradient gel electrophoresis (DGGE). It was interesting that the highest bacterial diversity appeared in the Fall season, not in summer. Our results indicated that Proteobacteria was the predominant member (23/46) in oyster tissues. Our results also suggested that bacterial diversity in gills was higher than that in digestive glands and other tissues. In addition, not all the bacteria collected from surrounding water by gills were transferred to digestive glands. On the other hand, few bacteria were found in oyster tissues except in the gills. Therefore, the gills could be the best candidate target tissue for monitoring of pathogenic bacteria either to human or to oyster.

  6. Bioavailability of lead in oysters fed to young Japanese quail

    SciTech Connect

    Stone, C.L.; Spivey Fox, M.R.; Hogye, K.S.

    1981-12-01

    The presence of lead in atmospheric particulates, soil, and seawater reflects the input of both domestic and industrial wastes. Because bivalves can concentrate large quantities of heavy metals, particularly lead, consumption of their meat may be a potential risk. The relative bioavailability of lead physiologicaly incorporated into oyster meat was investigated. Day-old Japanese quail were fed purified diets with three levels of lead added as either lead acetate, freeze-dried lead-dosed oyster, or lead acetate plus freeze-dried control oyster for 2 weeks. Feeding lead from any source had little or no effect on body weight, hemoglobin, hematocrit, or percentage ash in the tibia. The concentration of lead in tibia at each level of dietary lead for each type of diet was different from those for all other levels of dietary lead. Slope-ratio analysis of the data showed that lead intrinsically incorporated into oyster meat was 69-75% as bioavailable as lead in lead acetate at levels between 25 and 100 ppm dietary lead. The combinations of (1) control oyster meat with lead acetate and (2) lead acetate with copper and zinc levels equal to those in oyster meat gave responses similar to those of the lead-dosed oyster groups. Although these data showed lower bioavailability of lead in oyster meat as compared with lead acetate, the intercept of the lines at 25 ppm dietary lead suggests that the relative bioavailability may be reserved at lower levels of lead intake.

  7. Shell Games. VORTEX: Virginia's Oyster Reef Teaching EXperience.

    ERIC Educational Resources Information Center

    Harding, Juliana M.; Mann, Roger; Clark, Vicki P.

    This document introduces Virginia's Oyster Reef Teaching EXperience (VORTEX), which is an interdisciplinary program focusing on the importance of oyster reef communities in the Chesapeake Bay ecosystem. The VORTEX program uses field and laboratory experiences supported by multimedia instruction. This document presents an overview on the biology of…

  8. Steaming oysters does not prevent Norwalk-like gastroenteritis.

    PubMed Central

    Kirkland, K B; Meriwether, R A; Leiss, J K; Mac Kenzie, W R

    1996-01-01

    OBJECTIVES: To determine whether steaming oysters prevents gastroenteritis caused by small round structured (Norwalk-like) viruses and to identify risk factors for illness. METHODS: The authors interviewed all 48 people who ate oysters at two church suppers that were followed by outbreaks of gastroenteritis from a Norwalk-like virus. Data were collected on demographics, clinical illness, number of oysters eaten, and the extent to which they were cooked. RESULTS: Among the 48 persons, the attack rate was 56%. The risk of illness increased with the number of oysters eaten (chi-square for trend = 5.7, P = 0.02). There was no decrease in attack rates among persons who ate oysters that were better done (chi-square for trend = 1.1, P = 0.29). CONCLUSIONS: In these outbreaks, the risk of illness increased with the number of oysters eaten. Steaming oysters did not appear to prevent illness, suggesting that steaming may not be adequate to inactivate small round structured viruses. Public health messages that have emphasized the role of raw shellfish in the transmission of enteric viruses should be altered to increase the public's awareness that eating steamed oysters may also pose health risks. PMID:8955700

  9. CAN OYSTERS PLAY A ROLE IN ENVIRONMENTAL MANAGEMENT?

    EPA Science Inventory

    The culinary and commercial value of oysters is widely recognized but, until recently, their ecological importance has been largely overlooked. Field and laboratory studies have begun to explore how filter-feeding and reef building by oysters can influence nutrient cycling, biodi...

  10. Heritability of shell pigmentation in the Pacific oyster, Crassostrea gigas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Pacific oyster (Crassostrea gigas) is a species of considerable economic importance, with among the highest global production of any cultured aquatic animal species. In the interest of increasing the value of Pacific oysters sold as “singles” for the half-shell market, we explored the feasibili...

  11. Utilization of detrital complexes by the oyster, Crassostrea virginica (Gmelin)

    SciTech Connect

    Crosby, M.P.

    1987-01-01

    The contribution of bacteria and nonliving particulate organic matter of detrital complexes to the nutrition of the American oyster, Crassostrea virginica, was investigated in the laboratory under normal feeding conditions. Results indicate the oysters were capable of assimilating crude fiber extracted from /sup 14/C-Spartina alterniflora with an efficiency of approximately 3% and that enteric bacteria did not enhance this process. Less than 1% of an oyster's energetic demands could be met by direct utilization of this substrate, in the Choptank River subestuary of the Chesapeake Bay. The potential contribution of refractory organics to oysters in large salt marshes having crude fiber concentration greater than in the Choptank system, are discussed. The ability of the oyster to utilize /sup 14/C and /sup 15/N from cellulolytic marine bacteria, isolated from a S. alterniflora dominated salt marsh, was also studied.

  12. [Norovirus outbreak in Majorca (Spain) associated with oyster consumption].

    PubMed

    Galmés Truyols, Antònia; Duran, Jaume Giménez; Riutort, Antonio Nicolau; Cerdá, Gabriel Arbona; Isabel, Catalina Bosch; Arbona, Margarita Portell; Berga, Joana Vanrell

    2011-01-01

    We describe investigation into an outbreak of norovirus gastroenteritis associated with oyster consumption. A survey was conducted in 346 exposed persons, 266 of whom were cases. Only 14 feces samples from patients were sent to the National Microbiology Laboratory. Oysters collected at the production site were sent to the National Food Center. The oysters met the microbiological quality standard required before sale, which did not include virus investigation. Epidemiological analysis showed an association between gastroenteritis and consumption of oysters (OR = 60.4; 95% CI: 26.2-139.3) and razor shells (OR = 3.13; 95% CI: 1.4-6.9). Microbiological analysis confirmed norovirus in affected individuals but not in the oysters that had been tested after a longer purification period than those consumed. Food with a special risk of norovirus transmission should be strictly monitored. Investigators should dispose of the necessary laboratory resources to study food-borne norovirus outbreaks.

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

    PubMed Central

    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

  14. Norwalk Virus–specific Binding to Oyster Digestive Tissues

    PubMed Central

    Loisy, Fabienne; Atmar, Robert L.; Hutson, Anne M.; Estes, Mary K.; Ruvoën-Clouet, Nathalie; Pommepuy, Monique; Le Pendu, Jacques

    2006-01-01

    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. PMID:16707048

  15. Water quality parameters and total aerobic bacterial and vibrionaceae loads in eastern oysters (Crassostrea virginica) from oyster gardening sites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oyster gardening is a practice designed to restore habitat for marine life and to improve water quality. This study determined physical and chemical water quality parameters at two oyster gardening sites in the Delaware Inland Bays and compared them with total aerobic bacteria and Vibrionaceae conc...

  16. Effect of calcinated oyster shell powder on growth, yield, spawn run, and primordial formation of king oyster mushroom (Pleurotus eryngii).

    PubMed

    Choi, Ung-Kyu; Lee, Ok-Hwan; Kim, Young-Chan

    2011-03-10

    This study was conducted to evaluate the calcium (Ca) absorption efficacy of king oyster mushroom (Pleurotus eryngii) grown on sawdust medium supplemented with Ca-sources, including oyster shell powder, and to determine the efficacy of oyster shell powder as a calcium supplement on growth, yield, spawn run and primordial formation of P. eryngii. Optimum calcination of oyster shell powder was achieved at the temperature of 620.56 °C. A 1% supplementation of oyster shell powder in sawdust medium did not suppress the mycelial growth of P. eryngii. Also the supplementation of 2% calcinated oyster shell powder to sawdust medium potentially increased the calcium content up to a level of 315.7 ± 15.7 mg/100 g in the fruiting body of P. eryngii, without extension of duration of spawn run and the retardation of the days to primordial formation. These results suggest that the shellfish by-products, including oyster shell powder, can be utilized to develop calcium enriched king oyster mushrooms.

  17. Prevalence and characterization of Salmonella serovars isolated from oysters served raw in restaurants.

    PubMed

    Brillhart, Crystal D; Joens, Lynn A

    2011-06-01

    To determine if Salmonella-contaminated oysters are reaching consumer tables, a survey of raw oysters served in eight Tucson restaurants was performed from October 2007 to September 2008. Salmonella spp. were isolated during 7 of the 8 months surveyed and were present in 1.2% of 2,281 oysters tested. This observed prevalence is lower than that seen in a previous study in which U.S. market oysters were purchased from producers at bays where oysters are harvested. To test whether the process of refrigerating oysters in restaurants for several days reduces Salmonella levels, oysters were artificially infected with Salmonella and kept at 4°C for up to 13 days. Direct plate counts of oyster homogenate showed that Salmonella levels within oysters did not decrease during refrigeration. Six different serovars of Salmonella enterica were found in the restaurant oysters, indicating multiple incidences of Salmonella contamination of U.S. oyster stocks. Of the 28 contaminated oysters, 12 (43%) contained a strain of S. enterica serovar Newport that matched by pulsed-field gel electrophoresis a serovar Newport strain seen predominantly in the study of bay oysters performed in 2002. The repeated occurrence of this strain in oyster surveys is concerning, since the strain was resistant to seven antimicrobials tested and thus presents a possible health risk to consumers of raw oysters.

  18. Modelling Oyster Population Response to Variation in Freshwater Input

    NASA Astrophysics Data System (ADS)

    Livingston, R. J.; Lewis, F. G.; Woodsum, G. C.; Niu, X.-F.; Galperin, B.; Huang, W.; Christensen, J. D.; Monaco, M. E.; Battista, T. A.; Klein, C. J.; Howell, R. L.; Ray, G. L.

    2000-05-01

    This paper describes the linkage of a three-dimensional hydrodynamic circulation model with descriptive and experimental biological data concerning oyster (Crassostrea virginica) population dynamics in the Apalachicola Estuary (Florida, U.S.A.). Our intent was to determine the direct and indirect role of Apalachicola River flow in the maintenance of oyster production. Results of a monthly field sampling programme conducted on the oyster reefs in the Apalachicola system during 1985-1986 were used to develop statistical models relating several life-history characteristics of oysters to physical-chemical aspects of water quality. The same life-history characteristics were related statistically to output from a circulation model of Apalachicola Bay. Highest oyster densities and overall bar growth were found in the vicinity of the confluence of high salinity water moving westwards from St George Sound and river-dominated (low salinity) water moving south and eastwards from East Bay. With the exception of models for oyster mortality, the predictive capability of results from the parallel modelling efforts was low. A time-averaged model was developed for oyster mortality during the summer of 1985 by running a regression analysis with averaged predictors derived from the hydrodynamic model and observed (experimental) mortality rates throughout the estuary. A geographic information system was then used to depict the results spatially and to compare the extent of expected mortality in 1985 and 1986. High salinity, relatively low-velocity current patterns, and the proximity of a given oyster bar to entry points of saline Gulf water into the bay were important factors that contribute to increased oyster mortality. Mortality was a major determinant of oyster production in the Apalachicola Estuary with predation as a significant aspect of such mortality. By influencing salinity levels and current patterns throughout the bay, the Apalachicola River was important in controlling

  19. Deployed bivalves (oysters and clams) as indicators of estuarine condition

    SciTech Connect

    Ringwood, A.H.; Holland, A.F.; Keppler, C.; Wert, M.; Hyland, J.

    1995-12-31

    Hatchery-reared bivalves, oysters (Crassostrea virginica) and clams (Mercenaria mercenaria), were deployed simultaneously at reference and degraded sites in SC estuaries for approximately 1 month. Juvenile bivalves with endogenously high growth rates were used because effects on growth can be detected in a short time frame. The effects on growth and bioaccumulation of metal contaminants, as well as two biochemical indices (expression of metallothioneins, MT, and multi-xenobiotic transporting proteins, {at}R) were evaluated. Metal concentrations of sediments were also measured. Adverse effects on growth of both species were observed at degraded sites. However, oysters tended to grow more rapidly than clams, and adverse effects on oysters were more pronounced than in clams. Many of the sediments were characterized by elevated concentrations of multiple metals (Cu, Pb, Cr, etc.). However, increases in metal concentrations of oyster tissues were observed primarily with Cu, suggesting that many of the other metals had low bioavailability. There was little evidence of bioconcentration of any metals in clams. There was a significant correlation between sediment Cu and Cu in oyster tissues, but not in clams. Alterations in MT and MXR expression were also observed in oysters deployed at degraded sites. These studies suggest that oysters may be better in-situ indicators of habitat condition because they have more rapid growth rates and greater bioaccumulation potentials.

  20. Improved tolerance of metals in contaminated oyster larvae.

    PubMed

    Weng, Nanyan; Wang, Wen-Xiong

    2014-01-01

    Environmental stress experienced by parents may make a significant difference in the response of their offspring. However, relevant studies on marine bivalves are very limited especially for the field populations. In the present study, we examined the relative metal tolerance of offspring produced by four natural populations of oyster Crassostrea sikamea that were contaminated by metals to different degrees. We demonstrated that the resistance of oyster offspring to copper and zinc was correlated with the level of metal pollution experienced by the parent oysters. Specifically, the oyster embryo and larvae produced by adult oysters from contaminated sites had a much higher tolerance to metal stress than those from the reference sites. Furthermore, tissue concentration-dependent maternal transfer of Cu and Zn was found in this study, and the metallothionein concentrations in eggs were positively related to the total concentrations of maternally transferred Cu and Zn. Thus, the maternally transferred metals inducing high level of MT synthesis in eggs was one of the possible mechanisms responsible for the enhanced metal tolerance of oyster embryos and larvae from heavily contaminated sites. We concluded that environmental exposure history of adult oysters significantly influenced the ability of their offspring to cope with metal stress. Our findings offered the field evidence of the possible transfer of metal tolerance from adults to offspring in marine bivalves.

  1. Drought Increases Consumer Pressure on Oyster Reefs in Florida, USA.

    PubMed

    Garland, Hanna G; Kimbro, David L

    2015-01-01

    Coastal economies and ecosystems have historically depended on oyster reefs, but this habitat has declined globally by 85% because of anthropogenic activities. In a Florida estuary, we investigated the cause of newly reported losses of oysters. We found that the oyster reefs have deteriorated from north to south and that this deterioration was positively correlated with the abundance of carnivorous conchs and water salinity. In experiments across these gradients, oysters survived regardless of salinity if conchs were excluded. After determining that conchs were the proximal cause of oyster loss, we tested whether elevated water salinity was linked to conch abundance either by increasing conch growth and survivorship or by decreasing the abundance of a predator of conchs. In field experiments across a salinity gradient, we failed to detect spatial variation in predation on conchs or in conch growth and survivorship. A laboratory experiment, however, demonstrated the role of salinity by showing that conch larvae failed to survive at low salinities. Because this estuary's salinity increased in 2006 in response to reduced inputs of freshwater, we concluded that the ultimate cause of oyster decline was an increase in salinity. According to records from 2002 to 2012, oyster harvests have remained steady in the northernmost estuaries of this ecoregion (characterized by high reef biomass, low salinity, and low conch abundance) but have declined in the southernmost estuaries (characterized by lower reef biomass, increases in salinity, and increases in conch abundance). Oyster conservation in this ecoregion, which is probably one of the few that still support viable oyster populations, may be undermined by drought-induced increases in salinity causing an increased abundance of carnivorous conchs.

  2. Characterization of adhesive from oysters: A structural and compositional study

    NASA Astrophysics Data System (ADS)

    Alberts, Erik

    The inability for man-made adhesives to set in wet or humid environments is an ongoing challenging the design of biomedical and marine adhesive materials. However, we see that nature has already overcome this challenge. Mussels, barnacles, oysters and sandcastle worms all have unique mechanisms by which they attach themselves to surfaces. By understanding what evolution has already spent millions of years perfecting, we can design novel adhesive materials inspired by nature's elegant designs. The well-studied mussel is currently the standard for design of marine inspired biomimetic polymers. In the work presented here, we aim to provide new insights into the adhesive produced by the eastern oyster, Crassostrea virginica. Unlike the mussel, which produces thread-like plaques comprised of DOPA containing-protein, the oyster secretes an organic-inorganic hybrid adhesive as it settles and grows onto a surface. This form of adhesion renders the oyster to be permanently fixed in place. Over time, hundreds of thousands of oyster grow and agglomerate to form extensive reef structures. These reefs are not only essential to survival of the oyster, but are also vital to intertidal ecosystems. While the shell of the oyster has been extensively studied, curiously, only a few conflicting insights have been made into the nature of the adhesive and contact zone between shell and substrate, and even lesfs information has been ascertained on organic and inorganic composition. In this work, we provide microscopy and histochemical studies to characterize the structure and composition of the adhesive, using oyster in the adult and juvenile stages of life. Preliminary work on extracting and characterizing organic components through collaborative help with solid-state NMR (SSNMR) and proteomics are also detailed here. We aim to provide a full, comprehensive characterization of oyster adhesive so that in the future, we may apply what we learn to the design of new materials.

  3. Drought Increases Consumer Pressure on Oyster Reefs in Florida, USA

    PubMed Central

    Garland, Hanna G.; Kimbro, David L.

    2015-01-01

    Coastal economies and ecosystems have historically depended on oyster reefs, but this habitat has declined globally by 85% because of anthropogenic activities. In a Florida estuary, we investigated the cause of newly reported losses of oysters. We found that the oyster reefs have deteriorated from north to south and that this deterioration was positively correlated with the abundance of carnivorous conchs and water salinity. In experiments across these gradients, oysters survived regardless of salinity if conchs were excluded. After determining that conchs were the proximal cause of oyster loss, we tested whether elevated water salinity was linked to conch abundance either by increasing conch growth and survivorship or by decreasing the abundance of a predator of conchs. In field experiments across a salinity gradient, we failed to detect spatial variation in predation on conchs or in conch growth and survivorship. A laboratory experiment, however, demonstrated the role of salinity by showing that conch larvae failed to survive at low salinities. Because this estuary’s salinity increased in 2006 in response to reduced inputs of freshwater, we concluded that the ultimate cause of oyster decline was an increase in salinity. According to records from 2002 to 2012, oyster harvests have remained steady in the northernmost estuaries of this ecoregion (characterized by high reef biomass, low salinity, and low conch abundance) but have declined in the southernmost estuaries (characterized by lower reef biomass, increases in salinity, and increases in conch abundance). Oyster conservation in this ecoregion, which is probably one of the few that still support viable oyster populations, may be undermined by drought-induced increases in salinity causing an increased abundance of carnivorous conchs. PMID:26275296

  4. Hemocytes Are Sites of Enteric Virus Persistence within Oysters

    PubMed Central

    Provost, Keleigh; Dancho, Brooke A.; Ozbay, Gulnihal; Anderson, Robert S.; Richards, Gary P.; Kingsley, David H.

    2011-01-01

    The goal of this study was to determine how enteric viruses persist within shellfish tissues. Several lines of novel evidence show that phagocytic blood cells (hemocytes) of Eastern oysters (Crassostrea virginica) play an important role in the retention of virus particles. Our results demonstrated an association of virus contamination with hemocytes but not with hemolymph. Live oysters contaminated overnight with hepatitis A virus (HAV) and murine norovirus (MNV) had 56% and 80% of extractable virus associated with hemocytes, respectively. Transfer of HAV-contaminated hemocytes to naïve (virus-free) oysters resulted in naïve oyster meat testing HAV positive for up to 3 weeks. Acid tolerance of HAV, MNV, poliovirus (PV), and feline calicivirus (FCV) correlated with the ability of each virus to persist within oysters. Using reverse transcription-PCR (RT-PCR) to evaluate persistence of these viruses in oysters, we showed that HAV persisted the longest (>21 days) and was most acid resistant, MNV and PV were less tolerant of acidic pH, persisting for up to 12 days and 1 day, respectively, and FCV did not persist (<1 day) within oysters and was not acid tolerant. This suggests that the ability of a virus to tolerate the acidic conditions typical of phagolysosomal vesicles within hemocytes plays a role in determining virus persistence in shellfish. Evaluating oyster and hemocyte homogenates and live contaminated oysters as a prelude to developing improved viral RNA extraction methods, we found that viruses were extracted more expediently from hemocytes than from whole shellfish tissues and gave similar RT-PCR detection sensitivities. PMID:21948840

  5. Relationship between Marteilioides chungmuensis infection and reproduction in the Pacific oyster, Crassostrea gigas.

    PubMed

    Tun, Kay Lwin; Itoh, Naoki; Ueki, Noriyuki; Yoshinaga, Tomoyoshi; Ogawa, Kazuo

    2007-11-01

    Marteilioides chungmuensis, a protozoan paramyxean parasite, infects the oocytes of the Pacific oyster, Crassostrea gigas. The effects of infection on the reproductive cycle of C. gigas were investigated over two consecutive years at Okayama Prefecture, Japan. In male oysters, gonadal development began during February/March, maturity was achieved in June and spawning activity extended from July to September. In November and December, male oysters were not seen, probably because their gonads regressed to connective tissue and they transformed into undifferentiated oysters. By contrast, female oysters, in which parasite spore formation occurred, were still carrying oocytes until the following March and the spawning process of female oysters took 5 months longer than that of males in epizootic areas. The prevalence of M. chungmuensis infection increased from July to September, when most female oysters had their spawning period, and declined from October to the following April when oysters were at the spent stage. The prevalence of infection increased again in May of the following year and high prevalence was observed in the following July. When prevalence was compared between oysters of different age classes, higher prevalence was detected in older than in younger oysters. Histological examination showed that infected oysters produced oocytes continuously and spawned repeatedly from October to March, during which period healthy oysters were reproductively inactive. Parasites can infect the oocytes of infected oysters throughout the longer spawning period. These observations suggest that M. chungmuensis extends the reproductive period of infected oysters for its own reproductive benefit.

  6. Assessing shoreline exposure and oyster habitat suitability maximizes potential success for sustainable shoreline protection using restored oyster reefs.

    PubMed

    La Peyre, Megan K; Serra, Kayla; Joyner, T Andrew; Humphries, Austin

    2015-01-01

    Oyster reefs provide valuable ecosystem services that contribute to coastal resilience. Unfortunately, many reefs have been degraded or removed completely, and there are increased efforts to restore oysters in many coastal areas. In particular, much attention has recently been given to the restoration of shellfish reefs along eroding shorelines to reduce erosion. Such fringing reef approaches, however, often lack empirical data to identify locations where reefs are most effective in reducing marsh erosion, or fully take into account habitat suitability. Using monitoring data from 5 separate fringing reef projects across coastal Louisiana, we quantify shoreline exposure (fetch + wind direction + wind speed) and reef impacts on shoreline retreat. Our results indicate that fringing oyster reefs have a higher impact on shoreline retreat at higher exposure shorelines. At higher exposures, fringing reefs reduced marsh edge erosion an average of 1.0 m y(-1). Using these data, we identify ranges of shoreline exposure values where oyster reefs are most effective at reducing marsh edge erosion and apply this knowledge to a case study within one Louisiana estuary. In Breton Sound estuary, we calculate shoreline exposure at 500 random points and then overlay a habitat suitability index for oysters. This method and the resulting visualization show areas most likely to support sustainable oyster populations as well as significantly reduce shoreline erosion. Our results demonstrate how site selection criteria, which include shoreline exposure and habitat suitability, are critical to ensuring greater positive impacts and longevity of oyster reef restoration projects.

  7. Assessing shoreline exposure and oyster habitat suitability maximizes potential success for sustainable shoreline protection using restored oyster reefs

    PubMed Central

    Serra, Kayla; Joyner, T. Andrew; Humphries, Austin

    2015-01-01

    Oyster reefs provide valuable ecosystem services that contribute to coastal resilience. Unfortunately, many reefs have been degraded or removed completely, and there are increased efforts to restore oysters in many coastal areas. In particular, much attention has recently been given to the restoration of shellfish reefs along eroding shorelines to reduce erosion. Such fringing reef approaches, however, often lack empirical data to identify locations where reefs are most effective in reducing marsh erosion, or fully take into account habitat suitability. Using monitoring data from 5 separate fringing reef projects across coastal Louisiana, we quantify shoreline exposure (fetch + wind direction + wind speed) and reef impacts on shoreline retreat. Our results indicate that fringing oyster reefs have a higher impact on shoreline retreat at higher exposure shorelines. At higher exposures, fringing reefs reduced marsh edge erosion an average of 1.0 m y−1. Using these data, we identify ranges of shoreline exposure values where oyster reefs are most effective at reducing marsh edge erosion and apply this knowledge to a case study within one Louisiana estuary. In Breton Sound estuary, we calculate shoreline exposure at 500 random points and then overlay a habitat suitability index for oysters. This method and the resulting visualization show areas most likely to support sustainable oyster populations as well as significantly reduce shoreline erosion. Our results demonstrate how site selection criteria, which include shoreline exposure and habitat suitability, are critical to ensuring greater positive impacts and longevity of oyster reef restoration projects. PMID:26500825

  8. Assessing shoreline exposure and oyster habitat suitability maximizes potential success for sustainable shoreline protection using restored oyster reefs

    USGS Publications Warehouse

    LaPeyre, Megan K.; Serra, Kayla; Joyner, T. Andrew; Humphries, Austin T.

    2015-01-01

    Oyster reefs provide valuable ecosystem services that contribute to coastal resilience. Unfortunately, many reefs have been degraded or removed completely, and there are increased efforts to restore oysters in many coastal areas. In particular, much attention has recently been given to the restoration of shellfish reefs along eroding shorelines to reduce erosion. Such fringing reef approaches, however, often lack empirical data to identify locations where reefs are most effective in reducing marsh erosion, or fully take into account habitat suitability. Using monitoring data from 5 separate fringing reef projects across coastal Louisiana, we quantify shoreline exposure (fetch + wind direction + wind speed) and reef impacts on shoreline retreat. Our results indicate that fringing oyster reefs have a higher impact on shoreline retreat at higher exposure shorelines. At higher exposures, fringing reefs reduced marsh edge erosion an average of 1.0 m y−1. Using these data, we identify ranges of shoreline exposure values where oyster reefs are most effective at reducing marsh edge erosion and apply this knowledge to a case study within one Louisiana estuary. In Breton Sound estuary, we calculate shoreline exposure at 500 random points and then overlay a habitat suitability index for oysters. This method and the resulting visualization show areas most likely to support sustainable oyster populations as well as significantly reduce shoreline erosion. Our results demonstrate how site selection criteria, which include shoreline exposure and habitat suitability, are critical to ensuring greater positive impacts and longevity of oyster reef restoration projects.

  9. The density and spatial arrangement of the invasive oyster Crassostrea gigas determines its impact on settlement of native oyster larvae

    PubMed Central

    Wilkie, Emma M; Bishop, Melanie J; O'Connor, Wayne A

    2013-01-01

    Understanding how the density and spatial arrangement of invaders is critical to developing management strategies of pest species. The Pacific oyster, Crassostrea gigas, has been translocated around the world for aquaculture and in many instances has established wild populations. Relative to other species of bivalve, it displays rapid suspension feeding, which may cause mortality of pelagic invertebrate larvae. We compared the effect on settlement of Sydney rock oyster, Saccostrea glomerata, larvae of manipulating the spatial arrangement and density of native S. glomerata, and non-native C. gigas. We hypothesized that while manipulations of dead oysters would reveal the same positive relationship between attachment surface area and S. glomerata settlement between the two species, manipulations of live oysters would reveal differing density-dependent effects between the native and non-native oyster. In the field, whether oysters were live or dead, more larvae settled on C. gigas than S. glomerata when substrate was arranged in monospecific clumps. When, however, the two species were interspersed, there were no differences in larval settlement between them. By contrast, in aquaria simulating a higher effective oyster density, more larvae settled on live S. glomerata than C. gigas. When C. gigas was prevented from suspension feeding, settlement of larvae on C. gigas was enhanced. By contrast, settlement was similar between the two species when dead. While the presently low densities of the invasive oyster C. gigas may enhance S. glomerata larval settlement in east Australian estuaries, future increases in densities could produce negative impacts on native oyster settlement. Synthesis and applications: Our study has shown that both the spatial arrangement and density of invaders can influence their impact. Hence, management strategies aimed at preventing invasive populations reaching damaging sizes should not only consider the threshold density at which impacts exceed

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

    DTIC Science & Technology

    1984-06-20

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

  11. The biogeography of trophic cascades on US oyster reefs.

    PubMed

    Kimbro, David L; Byers, James E; Grabowski, Jonathan H; Hughes, A Randall; Piehler, Michael F

    2014-07-01

    Predators can indirectly benefit prey populations by suppressing mid-trophic level consumers, but often the strength and outcome of trophic cascades are uncertain. We manipulated oyster reef communities to test the generality of potential causal factors across a 1000-km region. Densities of oyster consumers were weakly influenced by predators at all sites. In contrast, consumer foraging behaviour in the presence of predators varied considerably, and these behavioural effects altered the trophic cascade across space. Variability in the behavioural cascade was linked to regional gradients in oyster recruitment to and sediment accumulation on reefs. Specifically, asynchronous gradients in these factors influenced whether the benefits of suppressed consumer foraging on oyster recruits exceeded costs of sediment accumulation resulting from decreased consumer activity. Thus, although predation on consumers remains consistent, predator influences on behaviour do not; rather, they interact with environmental gradients to cause biogeographic variability in the net strength of trophic cascades.

  12. Methods for recovering poliovirus and rotavirus from oysters.

    PubMed Central

    Speirs, J I; Pontefract, R D; Harwig, J

    1987-01-01

    Polioviruses and rotaviruses are potential indicators of sewage pollution of water and shellfish. Several methods for detecting these viruses in oysters were assessed. Elution-precipitation involving Catfloc for clarification and skim milk for subsequent flocculation resulted in the recovery of an average of 79% of poliovirus type 1 and 37% of rotavirus SA-11 from oyster homogenates inoculated with low numbers of these viruses. Adsorption-elution-precipitation did not improve the recovery of poliovirus and was detrimental to the recovery of rotavirus. Ultrafiltration or ultracentrifugation resulted in improved recovery of rotavirus but also in higher toxicity of oyster extracts to cell cultures. We recommend the use of the described elution-precipitation method for detecting viral pollutants in sample of oysters. PMID:2827573

  13. The Edibility and Cultivation of the Oyster Mushroom.

    ERIC Educational Resources Information Center

    Brenneman, James; Guttman, Mark C.

    1994-01-01

    Describes an enjoyable and fascinating experience that involves the cultivation of oyster mushrooms. By allowing students to participate in this process, the students are able to better understand the biology and utility of fungi. (ZWH)

  14. RELATIONSHIPS BETWEEN OYSTER (CRASSOSTREA VIRGINICA) DEFENSE MEASUREMENTS AND TISSUE CONTAMINANTS

    EPA Science Inventory

    Bivalve mollusks such as Crassostrea virginica typically inhabit estuaries and coastal areas that are increasingly contaminated with anthropogenic chemicals. Oysters may bioaccumulate large quantities of metals, polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCB...

  15. CHEMICAL EFFECTS ON OYSTER (CRASSOSTREA VIRGINICA) HEMOCYTE MICROBICIDAL ACTIVITY

    EPA Science Inventory

    Oyster (Crassostrea virginica) hemocytes, or blood cells, perform important internal defense functions such as phagocytosis and intracellular destruction of pathogens and bacteria. Using techniques such as phagocytosis and chemiluminescence assays, potential impairment of hemocyt...

  16. 20. View of Sterling Creek Marsh looking southwest with oyster ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. View of Sterling Creek Marsh looking southwest with oyster house in the tree line - Richmond Hill Plantation, Sterling Creek Marsh, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  17. Genotoxicity of diuron and glyphosate in oyster spermatozoa and embryos.

    PubMed

    Akcha, F; Spagnol, C; Rouxel, J

    2012-01-15

    We investigated the effects of genotoxicant exposure in gametes and embryos to find a possible link between genotoxicity and reproduction/developmental impairment, and explore the impact of chemical genotoxicity on population dynamics. Our study focused on the genotoxic effects of two herbicides on oyster gametes and embryos: glyphosate (both as an active substance and in the Roundup formulation) and diuron. France is Europe's leading consumer of agrochemical substances and as such, contamination of France's coastal waters by pesticides is a major concern. Glyphosate and diuron are among the most frequently detected herbicides in oyster production areas; as oyster is a specie with external reproduction, its gametes and embryos are in direct contact with the surrounding waters and are hence particularly exposed to these potentially dangerous substances. In the course of this study, differences in genotoxic and embryotoxic responses were observed in the various experiments, possibly due to differences in pollutant sensitivity between the tested genitor lots. Glyphosate and Roundup had no effect on oyster development at the concentrations tested, whereas diuron significantly affected embryo-larval development from the lowest tested concentration of 0.05 μg L⁻¹, i.e. an environmentally realistic concentration. Diuron may therefore have a significant impact on oyster recruitment rates in the natural environment. Our spermiotoxicity study revealed none of the tested herbicides to be cytotoxic for oyster spermatozoa. However, the alkaline comet assay showed diuron to have a significant genotoxic effect on oyster spermatozoa at concentrations of 0.05 μg L⁻¹ upwards. Conversely, no effects due to diuron exposure were observed on sperm mitochondrial function or acrosomal membrane integrity. Although our initial results showed no negative effect on sperm function, the possible impact on fertilization rate and the consequences of the transmission of damaged DNA for

  18. Phylogeny and Species Diversity of Gulf of California Oysters

    EPA Pesticide Factsheets

    Dataset of DNA sequence data from two mitochondrial loci (COI and 16S) used to infer the phylogeny of oysters in the genus Ostrea along the Pacific coast of North America.This dataset is associated with the following publication:Raith, M., D. Zacherl, E. Pilgrim , and D. Eernisse. Phylogeny and species diversity of Gulf of California oysters (Ostreidae) inferred from mitochondrial DNA. American Malacological Bulletin. American Malacological Society, Arlington, VA, USA, 33(2): 263-283, (2016).

  19. Magnitude and distribution pattern of zinc in oysters

    SciTech Connect

    Koki, A.K.; Whitmore, R.; Lester, L.C. Jr.

    1986-06-01

    This study was an attempt to assess the magnitude and distribution pattern of trace element zinc in oysters to see if the problem of the magnitude of zinc contamination was evident in the South Carolina Fishery. It would identify potentially hazardous situations and persons affected would be made aware of the problem. Where high zinc concentration are found in oysters, it would then attempt to identify the source of pollution.

  20. Ancient oyster shells on the atlantic continental shelf

    USGS Publications Warehouse

    Merrill, A.S.; Emery, K.O.; Rubin, M.

    1965-01-01

    Shells of long-dead Crassostrea virginica are reported at 71 stations in depths of 14 to 82 meters. The depths exceed those of the estuaries where the species flourishes. Radiocarbon measurements indicate that the oysters were alive 8000 to 11,000 years ago. It is concluded that the oysters lived in lagoons or estuaries which became submerged when the sea level rose at the end of the latest glacial epoch.

  1. Inducible defenses in Olympia oysters in response to an invasive predator.

    PubMed

    Bible, Jillian M; Griffith, Kaylee R; Sanford, Eric

    2017-03-01

    The prey naiveté hypothesis suggests that native prey may be vulnerable to introduced predators because they have not evolved appropriate defenses. However, recent evidence suggests that native prey sometimes exhibit induced defenses to introduced predators, as a result of rapid evolution or other processes. We examined whether Olympia oysters (Ostrea lurida) display inducible defenses in the presence of an invasive predator, the Atlantic oyster drill (Urosalpinx cinerea), and whether these responses vary among oyster populations from estuaries with and without this predator. We spawned oysters from six populations distributed among three estuaries in northern California, USA, and raised their offspring through two generations under common conditions to minimize effects of environmental history. We exposed second-generation oysters to cue treatments: drills eating oysters, drills eating barnacles, or control seawater. Oysters from all populations grew smaller shells when exposed to drill cues, and grew thicker and harder shells when those drills were eating oysters. Oysters exposed to drills eating other oysters were subsequently preyed upon at a slower rate. Although all oyster populations exhibited inducible defenses, oysters from the estuary with the greatest exposure to drills grew the smallest shells suggesting that oyster populations have evolved adaptive differences in the strength of their responses to predators. Our findings add to a growing body of literature that suggests that marine prey may be less likely to exhibit naiveté in the face of invasive predators than prey in communities that are more isolated from native predators, such as many freshwater and terrestrial island ecosystems.

  2. Copper and zinc contamination in oysters: subcellular distribution and detoxification.

    PubMed

    Wang, Wen-Xiong; Yang, Yubo; Guo, Xiaoyu; He, Mei; Guo, Feng; Ke, Caihuan

    2011-08-01

    Metal pollution levels in estuarine and coastal environments have been widely reported, but few documented reports exist of severe contamination in specific environments. Here, we report on a metal-contaminated estuary in Fujian Province, China, in which blue oysters (Crassostrea hongkongensis) and green oysters (Crassostrea angulata) were discovered to be contaminated with Cu and other metals. Extraordinarily high metal concentrations were found in the oysters collected from the estuary. Comparison with historical data suggests that the estuary has recently been contaminated with Cr, Cu, Ni, and Zn. Metal concentrations in blue oysters were as high as 1.4 and 2.4% of whole-body tissue dry wt for Cu and Zn, respectively. Cellular debris was the main subcellular fraction binding the metals, but metal-rich granules were important for Cr, Ni, and Pb. With increasing Cu accumulation, its partitioning into the cytosolic proteins decreased. In contrast, metallothionein-like proteins increased their importance in binding with Zn as tissue concentrations of Zn increased. In the most severely contaminated oysters, only a negligible fraction of their Cu and Zn was bound with the metal-sensitive fraction, which may explain the survival of oysters in such contaminated environments.

  3. Raw oysters can be a risk for infections.

    PubMed

    Vieira, Regine Helena Silva dos Fernandes; de Sousa, Oscarina Viana; Costa, Renata Albuquerque; Theophilo, Grace Nazareth Diogo; Macrae, Andrew; Fonteles Filho, Antonio Adauto; Rodrigues, Dália dos Prazeres

    2010-01-01

    The aims of this study were to count and identify sucrose positive and negative vibrios isolated from cultivated Crassostrea rhizophorae oysters during their growing cycle. Every month for 12 months, 10 to 18 oysters were collected for study. Collections occurred at the Center for Studies of Coastal Aquaculture (CSCA), which is associated with the Institute of Marine Science, Labomar, located in Euzebio, Ceará, Brazil. Approximately 150 oysters and their intervalvular liquor were studied. Vibrio Standard Plates Counts (SPC) from oyster meat and their intervalvular liquor varied from 25 to 59,000,000 CFU/g. For most of the 12 months of the oysters' life, it was possible to identify Vibrio parahaemolyticus. Vibrio carchariae was identified in four collections. Among other isolated species, the most important, considering public health risks, was V. vulnificus, although only one strain was confirmed. We concluded that retail purchased oysters should never be eaten raw or undercooked because many species of the genus Vibrio are known to be pathogenic to humans and live naturally on and in shellfish throughout their life cycle.

  4. Oyster shell as substitute for aggregate in mortar.

    PubMed

    Yoon, Hyunsuk; Park, Sangkyu; Lee, Kiho; Park, Junboum

    2004-06-01

    Enormous amounts of oyster shell waste have been illegally disposed of at oyster farm sites along the southern coast of Korea. In this study to evaluate the possibility of recycling this waste for use as a construction material, the mechanical characteristics of pulverized oyster shell were investigated in terms of its potential utilization as a substitute for the aggregates used in mortar. The unconfined compressive strengths of various soil mortar specimens, with varying blending ratios of cement, water and oyster shell, were evaluated by performing unconfined compression tests, and the results were compared with the strengths of normal cement mortar made with sand. In addition, the effect of organic chemicals on the hardening of concrete was evaluated by preparing ethyl-benzene-mixed mortar specimens. The long-term strength improvement resulting from the addition of fly ash was also examined by performing unconfined compression tests on specimens with fly-ash content. There was no significant reduction in the compressive strength of the mortars containing small oyster shell particles instead of sand. From these test data, the possible application of oyster shells in construction materials could be verified, and the change in the strength parameters according to the presence of organic compounds was also evaluated.

  5. High-pressure treatment for shelf-life extension and quality improvement of oysters cooked in a traditional Taiwanese oyster omelet.

    PubMed

    Lai, Kung-Ming; Chi, Hsin-Yi; Hsu, Kuo-Chiang

    2010-01-01

    Whole oysters were processed using high-pressure (HP) treatment at 250 and 300 MPa for 0 to 10 min and stored at 4 degrees Celsius for up to 28 days. HP-treated oysters and untreated oysters were evaluated for lipid oxidation, growth of microorganisms, and sensory characteristics after cooking at 160 degrees Celsius for 90 s. Microbial counts after HP treatment revealed that the bacterial load was initially reduced at all pressures. HP-treated oysters had significantly higher pH and moisture (P < 0.05) relative to control (untreated) oysters during storage. HP treatment increased lipid oxidation with unpleasant odor during storage compared with the control. HP treatment decreased redness but did not significantly affect the brightness and yellowness of cooked oysters. From tests of mechanical properties, 300 MPa-treated oysters after cooking had significantly increased toughness as measured by cutting force. HP-treated oysters after cooking received higher quality scores than did the control during the storage trial. Results indicated that 300 MPa for 2 min is the optimum HP treatment that results in oysters most acceptable for oyster omelets during storage at 4 degrees Celsius, and this treatment may extend the shelf life of these oysters to 21 days.

  6. Predicting the effects of proposed Mississippi River diversions on oyster habitat quality; application of an oyster habitat suitability index model

    USGS Publications Warehouse

    Soniat, Thomas M.; Conzelmann, Craig P.; Byrd, Jason D.; Roszell, Dustin P.; Bridevaux, Joshua L.; Suir, Kevin J.; Colley, Susan B.

    2013-01-01

    In an attempt to decelerate the rate of coastal erosion and wetland loss, and protect human communities, the state of Louisiana developed its Comprehensive Master Plan for a Sustainable Coast. The master plan proposes a combination of restoration efforts including shoreline protection, marsh creation, sediment diversions, and ridge, barrier island, and hydrological restoration. Coastal restoration projects, particularly the large-scale diversions of fresh water from the Mississippi River, needed to supply sediment to an eroding coast potentially impact oyster populations and oyster habitat. An oyster habitat suitability index model is presented that evaluates the effects of a proposed sediment and freshwater diversion into Lower Breton Sound. Voluminous freshwater, needed to suspend and broadly distribute river sediment, will push optimal salinities for oysters seaward and beyond many of the existing reefs. Implementation and operation of the Lower Breton Sound diversion structure as proposed would render about 6,173 ha of hard bottom immediately east of the Mississippi River unsuitable for the sustained cultivation of oysters. If historical harvests are to be maintained in this region, a massive and unprecedented effort to relocate private leases and restore oyster bottoms would be required. Habitat suitability index model results indicate that the appropriate location for such efforts are to the east and north of the Mississippi River Gulf Outlet.

  7. 77 FR 135 - Exelon Generation Company, LLC, Oyster Creek Nuclear Generating Station; Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-03

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Exelon Generation Company, LLC, Oyster Creek Nuclear Generating Station; Exemption 1.0 Background...-16, which authorizes operation of the Oyster Creek Nuclear Generating Station (OCNGS). The...

  8. DIFFERENTIAL EFFECTS OF OYSTER (CRASSOSTREA VIRGINICA) DEFENSES ON CLINICAL AND ENVIRONMENTAL ISOLATES OF VIBRIO PARAHEMOLYTICUS

    EPA Science Inventory

    Three clinical (2030, 2062, and 2107) and three environmental (1094, 1163, and ATCC 17802) isolates of Vibrio parahaemolyticus were exposed to hemocytes and plasma collected from oysters (Crassostrea virginica) to determine their susceptibility to putative oyster defenses. Clinic...

  9. RESPONSES OF OYSTER (CRASSOSTREA VIRGINICA) HEMOCYTES TO NONPATHOGENIC AND CLINICAL ISOLATES OF VIBRIO PARAHAEMOLYTICUS

    EPA Science Inventory

    Bacterial uptake by oysters (Crassostrea virginica) and bactericidal activity of oyster hemocytes were studied using four environmental isolates and three clinical isolates of Vibrio parahaemolyticus. Clinical isolates (2030, 2062, 2107) were obtained from gastroenteritis patien...

  10. PERKINSUS-"CIDAL" ACTIVITY OF OYSTER HEMOCYTES USING A TETRAZOLIUM DYE REDUCTION ASSAY: OPTIMIZATION AND APPLICATIONS

    EPA Science Inventory

    A bactericidal assay developed to assess the ability of oyster (Crassostrea virginica) hemocytes to kill the human pathogen Vibrio parahaemolyticus was optimized to estimate killing of the oyster parasite Perkinsus marinus. Assay variables, temperature, hemocyte:parasite ratio, i...

  11. Respirators, internal dose, and Oyster Creek

    SciTech Connect

    Michal, R.

    1996-06-01

    This article looks at the experience of Oyster Creek in relaxing the requirements for the use of respirators in all facets of plant maintenance, on the overall dose received by plant maintenance personnel. For Roger Shaw, director of radiological controls for three years at GPU Nuclear Corporation`s Oyster Creek nuclear plant the correct dose balance is determined on a job-by-job basis: Does the job require a respirator, which is an effective means of decreasing worker inhalation of airborne radioactive particles? Will wearing a respirator slow down a worker, consequently increasing whole body radiation exposure by prolonging the time spent in fields of high external radiation? How does respiratory protection affect worker safety and to what degree? While changes to the Nuclear Regulatory Commission`s 10CFR20 have updated the radiation protection requirements for the nuclear industry, certain of the revisions have been directed specifically at reducing worker dose, Shaw said. {open_quotes}It basically delineates that dose is dose,{close_quotes} Shaw said, {open_quotes}regardless of whether it is acquired externally or internally.{close_quotes} The revision of Part 20 changed the industry`s attitude toward internal dose, which had always been viewed negatively. {open_quotes}Internal dose was always seen as preventable by wearing respirators and by using engineering techniques such as ventilation control and decontamination,{close_quotes} Shaw said, {open_quotes}whereas external dose, although reduced where practical, was seen as a fact of the job.{close_quotes}

  12. 21 CFR 161.30 - Declaration of quantity of contents on labels for canned oysters.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... canned oysters. 161.30 Section 161.30 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH....30 Declaration of quantity of contents on labels for canned oysters. (a) For many years packers of canned oysters in the Gulf area of the United States have labeled their output with a declaration of...

  13. 75 FR 33366 - Exelon Generation Company, LLC; Oyster Creek Nuclear Generating Station; Notice of Withdrawal of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ... COMMISSION Exelon Generation Company, LLC; Oyster Creek Nuclear Generating Station; Notice of Withdrawal of..., application for amendment to Facility Operating License No. DPR-16 for the Oyster Creek Nuclear Generating Station (Oyster Creek), located in Ocean County, New Jersey. The proposed amendment would have revised...

  14. 40 CFR 408.270 - Applicability; description of the steamed and canned oyster processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... steamed and canned oyster processing subcategory. 408.270 Section 408.270 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Steamed and Canned Oyster Processing Subcategory § 408.270 Applicability; description of the steamed and canned oyster processing subcategory. The provisions of this subpart...

  15. 21 CFR 161.30 - Declaration of quantity of contents on labels for canned oysters.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... canned oysters. 161.30 Section 161.30 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH....30 Declaration of quantity of contents on labels for canned oysters. (a) For many years packers of canned oysters in the Gulf area of the United States have labeled their output with a declaration of...

  16. 40 CFR 408.270 - Applicability; description of the steamed and canned oyster processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... steamed and canned oyster processing subcategory. 408.270 Section 408.270 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Steamed and Canned Oyster Processing Subcategory § 408.270 Applicability; description of the steamed and canned oyster processing subcategory. The provisions of this subpart...

  17. 21 CFR 161.30 - Declaration of quantity of contents on labels for canned oysters.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... canned oysters. 161.30 Section 161.30 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH....30 Declaration of quantity of contents on labels for canned oysters. (a) For many years packers of canned oysters in the Gulf area of the United States have labeled their output with a declaration of...

  18. 40 CFR 408.270 - Applicability; description of the steamed and canned oyster processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... steamed and canned oyster processing subcategory. 408.270 Section 408.270 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Steamed and Canned Oyster Processing Subcategory § 408.270 Applicability; description of the steamed and canned oyster processing subcategory. The provisions of this subpart...

  19. 40 CFR 408.270 - Applicability; description of the steamed and canned oyster processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... steamed and canned oyster processing subcategory. 408.270 Section 408.270 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Steamed and Canned Oyster Processing Subcategory § 408.270 Applicability; description of the steamed and canned oyster processing subcategory. The provisions of this subpart...

  20. 21 CFR 161.30 - Declaration of quantity of contents on labels for canned oysters.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... canned oysters. 161.30 Section 161.30 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH....30 Declaration of quantity of contents on labels for canned oysters. (a) For many years packers of canned oysters in the Gulf area of the United States have labeled their output with a declaration of...

  1. 75 FR 33656 - Exelon Generation Company, LLC Oyster Creek Nuclear Generating Station Environmental Assessment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-14

    ... COMMISSION Exelon Generation Company, LLC Oyster Creek Nuclear Generating Station Environmental Assessment....2, as requested by Exelon Generation Company, LLC (the licensee), for operation of the Oyster Creek Nuclear Generating Station (Oyster Creek), located in Ocean County, New Jersey. Therefore, as required...

  2. 21 CFR 161.30 - Declaration of quantity of contents on labels for canned oysters.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... canned oysters. 161.30 Section 161.30 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH....30 Declaration of quantity of contents on labels for canned oysters. (a) For many years packers of canned oysters in the Gulf area of the United States have labeled their output with a declaration of...

  3. 40 CFR 408.270 - Applicability; description of the steamed and canned oyster processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... steamed and canned oyster processing subcategory. 408.270 Section 408.270 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Steamed and Canned Oyster Processing Subcategory § 408.270 Applicability; description of the steamed and canned oyster processing subcategory. The provisions of this subpart...

  4. PARASITIC AND SYMBIOTIC FAUNA INHABITING OYSTERS (CRASSOSTREA VIRGINICA) SAMPLED FROM THE CALOOSAHATCHEE ESTUARY, FL

    EPA Science Inventory

    Oysters, Crassostrea virginica, inhabiting 5 sites in the Caloosahatchee River estuary were studied over a 13 month period to determine the suitability of oyster habitat in relation to their health and condition. Histological examination of 650 oysters (10 animals per station per...

  5. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest). Olympia Oyster

    DTIC Science & Technology

    1989-12-01

    oysters was spread in the dyked beds The maximum reported size of Olympia oysters and left for 3.5 to 5 years until most of the is 75 mm ( Hertlein ...rangec. In elevations. They are found at depths of’ 0 to California, the bat ray Myliobatis californica is 71 m ( Hertlein 1959). Oysters may attach to an

  6. Detection of hepatitis A virus and bacterial contamination in raw oysters in Thailand.

    PubMed

    Kittigul, Leera; Pombubpa, Kannika; Sukonthalux, Suntharee; Rattanatham, Tippawan; Utrarachkij, Fuangfa; Diraphat, Pornphan

    2010-01-01

    This study was conducted to determine the presence of hepatitis A virus (HAV) in raw oysters (Crassostrea belcheri) using a virus concentration method and reverse transcription-nested polymerase chain reaction (RT-nested PCR). A total of 220 oyster samples were collected from oyster farms and local markets in Thailand. HAV was found in three oyster samples. Nested PCR products of HAV detected in oysters were characterized further by DNA sequencing of the VP1/2A region and subjected to phylogenetic analysis. All HAV sequences (168 basepairs) were associated with human HAV subgenotype IB (GIB). Fecal coliforms and Escherichia coli were determined using the multiple tube fermentation method, to assess the microbiological quality of collected oysters. Among oyster samples tested, 65% had fecal coliforms higher than the standard level for raw shellfish [< 20 Most Probable Numbers (MPN)/g]; MPN values in the range of 21.0-4.6 x 10(4)/g. Most oyster samples (85%) were contaminated with E. coli in the range of 3.0-4.6 x 10(4) MPN/g. One oyster sample with an acceptable level of fecal coliforms contained HAV GIB. E. coli was found in all HAV-positive oyster samples. The results suggest a significant presence of HAV and bacterial indicators of fecal contamination in raw oysters, which are a health risk for consumers and a source of gastrointestinal illness. Enteric viruses should also be tested to assess the microbiological quality of oysters.

  7. Mortalities of eastern and pacific oyster larvae caused by the pathogens Vibrio coralliilyticus and Vibrio tubiashii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vibrio tubiashii is reported to be a bacterial pathogen of larval Eastern oysters (Crassostrea virginica) and Pacific oysters (Crassostrea gigas) and has been associated with major hatchery crashes, causing shortages in seed oysters for commercial shellfish producers. Another bacterium, Vibrio cora...

  8. Reconstructing early 17th century estuarine drought conditions from Jamestown oysters.

    PubMed

    Harding, Juliana M; Spero, Howard J; Mann, Roger; Herbert, Gregory S; Sliko, Jennifer L

    2010-06-08

    Oysters (Crassostrea virginica) were a central component of the Chesapeake Bay ecosystem in 1607 when European settlers established Jamestown, VA, the first permanent English settlement in North America. These estuarine bivalves were an important food resource during the early years of the James Fort (Jamestown) settlement while the colonists were struggling to survive in the face of inadequate supplies and a severe regional drought. Although oyster shells were discarded as trash after the oysters were eaten, the environmental and ecological data recorded in the bivalve geochemistry during shell deposition remain intact over centuries, thereby providing a unique window into conditions during the earliest Jamestown years. We compare oxygen isotope data from these 17th century oyster shells with modern shells to quantify and contrast estuarine salinity, season of oyster collection, and shell provenance during Jamestown colonization (1609-1616) and the 21st century. Data show that oysters were collected during an extended drought between fall 1611 and summer 1612. The drought shifted the 14 psu isohaline above Jamestown Island, facilitating individual oyster growth and extension of oyster habitat upriver toward the colony, thereby enhancing local oyster food resources. Data from distinct well layers suggest that the colonists also obtained oysters from reefs near Chesapeake Bay to augment oyster resources near Jamestown Island. The oyster shell season of harvest reconstructions suggest that these data come from either a 1611 well with a very short useful period or an undocumented older well abandoned by late 1611.

  9. Isolation of Vibrio cholerae serotype O1 from the eastern oyster, Crassostrea virginica.

    PubMed Central

    Hood, M A; Ness, G E; Rodrick, G E

    1981-01-01

    Two strains of Vibrio cholerae serotype O1 Inaba were isolated from eastern oysters, Crassostrea virginica, collected from estuarine waters in Florida during April 1980. The oyster meats and waters from which the oysters were collected had low fecal coliform counts, and the area had no prior evidence of sewage contamination. PMID:7235700

  10. Oyster reproduction is affected by exposure to polystyrene microplastics.

    PubMed

    Sussarellu, Rossana; Suquet, Marc; Thomas, Yoann; Lambert, Christophe; Fabioux, Caroline; Pernet, Marie Eve Julie; Le Goïc, Nelly; Quillien, Virgile; Mingant, Christian; Epelboin, Yanouk; Corporeau, Charlotte; Guyomarch, Julien; Robbens, Johan; Paul-Pont, Ika; Soudant, Philippe; Huvet, Arnaud

    2016-03-01

    Plastics are persistent synthetic polymers that accumulate as waste in the marine environment. Microplastic (MP) particles are derived from the breakdown of larger debris or can enter the environment as microscopic fragments. Because filter-feeder organisms ingest MP while feeding, they are likely to be impacted by MP pollution. To assess the impact of polystyrene microspheres (micro-PS) on the physiology of the Pacific oyster, adult oysters were experimentally exposed to virgin micro-PS (2 and 6 µm in diameter; 0.023 mg·L(-1)) for 2 mo during a reproductive cycle. Effects were investigated on ecophysiological parameters; cellular, transcriptomic, and proteomic responses; fecundity; and offspring development. Oysters preferentially ingested the 6-µm micro-PS over the 2-µm-diameter particles. Consumption of microalgae and absorption efficiency were significantly higher in exposed oysters, suggesting compensatory and physical effects on both digestive parameters. After 2 mo, exposed oysters had significant decreases in oocyte number (-38%), diameter (-5%), and sperm velocity (-23%). The D-larval yield and larval development of offspring derived from exposed parents decreased by 41% and 18%, respectively, compared with control offspring. Dynamic energy budget modeling, supported by transcriptomic profiles, suggested a significant shift of energy allocation from reproduction to structural growth, and elevated maintenance costs in exposed oysters, which is thought to be caused by interference with energy uptake. Molecular signatures of endocrine disruption were also revealed, but no endocrine disruptors were found in the biological samples. This study provides evidence that micro-PS cause feeding modifications and reproductive disruption in oysters, with significant impacts on offspring.

  11. Freshwater Detention by Oyster Reefs: Quantifying a Keystone Ecosystem Service.

    PubMed

    Kaplan, David A; Olabarrieta, Maitane; Frederick, Peter; Valle-Levinson, Arnoldo

    2016-01-01

    Oyster reefs provide myriad ecosystem services, including water quality improvement, fisheries and other faunal support, shoreline protection from erosion and storm surge, and economic productivity. However, their role in directing flow during non-storm conditions has been largely neglected. In regions where oyster reefs form near the mouth of estuarine rivers, they likely alter ocean-estuary exchange by acting as fresh water "dams". We hypothesize that these reefs have the potential to detain fresh water and influence salinity over extensive areas, thus providing a "keystone" ecosystem service by supporting estuarine functions that rely on the maintenance of estuarine (i.e., brackish) conditions in the near-shore environment. In this work, we investigated the effects of shore-parallel reefs on estuarine salinity using field data and hydrodynamic modeling in a degraded reef complex in the northeastern Gulf of Mexico. Results suggested that freshwater detention by long linear chains of oyster reefs plays an important role in modulating salinities, not only in the oysters' local environment, but over extensive estuarine areas (tens of square kilometers). Field data confirmed the presence of salinity differences between landward and seaward sides of the reef, with long-term mean salinity differences of >30% between sides. Modeled results expanded experimental findings by illustrating how oyster reefs affect the lateral and offshore extent of freshwater influence. In general, the effects of simulated reefs were most pronounced when they were highest in elevation, without gaps, and when riverine discharge was low. Taken together, these results describe a poorly documented ecosystem service provided by oyster reefs; provide an estimate of the magnitude and spatial extent of this service; and offer quantitative information to help guide future oyster reef restoration.

  12. Oyster reproduction is affected by exposure to polystyrene microplastics

    PubMed Central

    Sussarellu, Rossana; Suquet, Marc; Thomas, Yoann; Lambert, Christophe; Fabioux, Caroline; Pernet, Marie Eve Julie; Le Goïc, Nelly; Quillien, Virgile; Mingant, Christian; Epelboin, Yanouk; Corporeau, Charlotte; Guyomarch, Julien; Robbens, Johan; Paul-Pont, Ika; Soudant, Philippe; Huvet, Arnaud

    2016-01-01

    Plastics are persistent synthetic polymers that accumulate as waste in the marine environment. Microplastic (MP) particles are derived from the breakdown of larger debris or can enter the environment as microscopic fragments. Because filter-feeder organisms ingest MP while feeding, they are likely to be impacted by MP pollution. To assess the impact of polystyrene microspheres (micro-PS) on the physiology of the Pacific oyster, adult oysters were experimentally exposed to virgin micro-PS (2 and 6 µm in diameter; 0.023 mg·L−1) for 2 mo during a reproductive cycle. Effects were investigated on ecophysiological parameters; cellular, transcriptomic, and proteomic responses; fecundity; and offspring development. Oysters preferentially ingested the 6-µm micro-PS over the 2-µm-diameter particles. Consumption of microalgae and absorption efficiency were significantly higher in exposed oysters, suggesting compensatory and physical effects on both digestive parameters. After 2 mo, exposed oysters had significant decreases in oocyte number (−38%), diameter (−5%), and sperm velocity (−23%). The D-larval yield and larval development of offspring derived from exposed parents decreased by 41% and 18%, respectively, compared with control offspring. Dynamic energy budget modeling, supported by transcriptomic profiles, suggested a significant shift of energy allocation from reproduction to structural growth, and elevated maintenance costs in exposed oysters, which is thought to be caused by interference with energy uptake. Molecular signatures of endocrine disruption were also revealed, but no endocrine disruptors were found in the biological samples. This study provides evidence that micro-PS cause feeding modifications and reproductive disruption in oysters, with significant impacts on offspring. PMID:26831072

  13. Molecular and histological identification of Marteilioides infection in Suminoe Oyster Crassostrea ariakensis, Manila Clam Ruditapes philippinarum and Pacific Oyster Crassostrea gigas on the south coast of Korea.

    PubMed

    Limpanont, Yanin; Yanin, Limpanont; Kang, Hyun-Sil; Hong, Hyun-Ki; Jeung, Hee-Do; Kim, Bong-Kyu; Le, Thanh Cuong; Kim, Young-Ok; Choi, Kwang-Sik

    2013-11-01

    The oyster ovarian parasite Marteilioides chungmuensis has been reported from Korea and Japan, damaging the oyster industries. Recently, Marteilioides-like organisms have been identified in other commercially important marine bivalves. In this study, we surveyed Marteilioides infection in the Manila clam Ruditapes philippinarum, Suminoe oyster Crassostrea ariakensis, and Pacific oyster Crassostrea gigas, using histology and Marteilioides-specific small subunit (SSU) rDNA PCR. The SSU rDNA sequence of M. chungmuensis (1716 bp) isolated from C. gigas in Tongyoung bay was 99.9% similar to that of M. chungmuensis reported in Japan. Inclusions of multi-nucleated bodies in the oocytes, typical of Marteilioides infection, were identified for the first time in Suminoe oysters. The SSU rDNA sequence of a Marteilioides-like organism isolated from Suminoe oysters was 99.9% similar to that of M. chungmuensis. Marteilioides sp. was also observed from 7 Manila clams of 1840 individuals examined, and the DNA sequences of which were 98.2% similar to the known sequence of M. chungmuensis. Unlike Marteilioides infection of Pacific oysters, no remarkable pathological symptoms, such as large multiple lumps on the mantle, were observed in infected Suminoe oysters or Manila clams. Distribution of the infected Manila clams, Suminoe oysters and Pacific oysters was limited to small bays on the south coast, suggesting that the southern coast is the enzootic area of Marteilioides infection.

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  15. Genetic improvement for disease resistance in oysters: A review.

    PubMed

    Dégremont, Lionel; Garcia, Céline; Allen, Standish K

    2015-10-01

    Oyster species suffer from numerous disease outbreaks, often causing high mortality. Because the environment cannot be controlled, genetic improvement for disease resistance to pathogens is an attractive option to reduce their impact on oyster production. We review the literature on selective breeding programs for disease resistance in oyster species, and the impact of triploidy on such resistance. Significant response to selection to improve disease resistance was observed in all studies after two to four generations of selection for Haplosporidium nelsoni and Roseovarius crassostrea in Crassostrea virginica, OsHV-1 in Crassostrea gigas, and Martelia sydneyi in Saccostrea glomerata. Clearly, resistance in these cases was heritable, but most of the studies failed to provide estimates for heritability or genetic correlations with other traits, e.g., between resistance to one disease and another. Generally, it seems breeding for higher resistance to one disease does not confer higher resistance or susceptibility to another disease. For disease resistance in triploid oysters, several studies showed that triploidy confers neither advantage nor disadvantage in survival, e.g., OsHV-1 resistance in C. gigas. Other studies showed higher disease resistance of triploids over diploid as observed in C. virginica and S. glomerata. One indirect mechanism for triploids to avoid disease was to grow faster, thus limiting the span of time when oysters might be exposed to disease.

  16. Bioaccumulation of perfluorochemicals in Pacific oyster under different salinity gradients.

    PubMed

    Jeon, Junho; Kannan, Kurunthachalam; Lim, Han Kyu; Moon, Hyo Bang; Ra, Jin Sung; Kim, Sang Don

    2010-04-01

    Despite the reports of widespread occurrence of perfluorinated compounds (PFCs) in estuarine and coastal waters and open seas, little is known on the effect of salinity on bioaccumulation. In this study, effects of salinity on bioaccumulation of PFCs in Pacific oysters (Crassostrea gigas) were investigated. Furthermore, partitioning of PFCs between water and particles (oysters' food) was examined at different salinities. The distribution coefficients (K(d); partitioning between water and particles) for selected PFCs, that is, PFOS, PFOA, PFDA, and PFUnDA, increased by 2.1- to 2.7-fold with the increase in water salinity from 10 to 34 psu, suggesting "salting-out" effect, and the salting constant (delta) was estimated to range from 0.80 to 1.11. The nonlinear regression analysis of bioaccumulation suggested increase in aqueous and dietary uptake rates (K(w) and K(f)), with the increase in salinity, which resulted in elevated bioaccumulation, although the depuration rates (K(e)) also increased. The relative abundance of long carbon chain length PFCs (i.e., PFDA and PFUnDA) increased as salinity increased, while the proportion of PFOS and PFOA decreased, which is explained by the positive relationship between delta and carbon chain length. The contribution of diet to bioaccumulation in oysters ranged from 18 to 92%. Overall, salinity not only affected the chemistry of PFCs, but also the physiology of oysters, contributing to sorption and bioaccumulation of perfluorochemicals in oysters.

  17. Shell hardness and compressive strength of the Eastern oyster, Crassostrea virginica, and the Asian oyster, Crassostrea ariakensis.

    PubMed

    Lombardi, Sara A; Chon, Grace D; Lee, James Jin-Wu; Lane, Hillary A; Paynter, Kennedy T

    2013-12-01

    The valves of oysters act as a physical barrier between tissues and the external environment, thereby protecting the oyster from environmental stress and predation. To better understand differences in shell properties and predation susceptibilities of two physiologically and morphologically similar oysters, Crassostrea virginica and Crassostrea ariakensis, we quantified and compared two mechanical properties of shells: hardness (resistance to irreversible deformation; GPa) and compressive strength (force necessary to produce a crack; N). We found no differences in the hardness values between foliated layers (innermost and outermost foliated layers), age class (C. virginica: 1, 4, 6, 9 years; C. ariakensis: 4, 6 years), or species. This suggests that the foliated layers have similar properties and are likely composed of the same material. The compressive force required to break wet and dry shells was also not different. However, the shells of both six- and nine-year-old C. virginica withstood higher compressive force than C. virginica shells aged either one or four, and the shells of C. ariakensis at both ages studied (4- and 6-years-old). Differences in ability to withstand compressive force are likely explained by differences in thickness and density between age classes and species. Further, we compared the compressive strength of differing ages of these two species to the crushing force of common oyster predators in the Chesapeake Bay. By studying the physical properties of shells, this work may contribute to a better understanding of the mechanical defenses of oysters as well as of their predation vulnerabilities.

  18. Vibrio bacteria in raw oysters: managing risks to human health.

    PubMed

    Froelich, Brett A; Noble, Rachel T

    2016-03-05

    The human-pathogenic marine bacteria Vibrio vulnificus and V. parahaemolyticus are strongly correlated with water temperature, with concentrations increasing as waters warm seasonally. Both of these bacteria can be concentrated in filter-feeding shellfish, especially oysters. Because oysters are often consumed raw, this exposes people to large doses of potentially harmful bacteria. Various models are used to predict the abundance of these bacteria in oysters, which guide shellfish harvest policy meant to reduce human health risk. Vibrio abundance and behaviour varies from site to site, suggesting that location-specific studies are needed to establish targeted risk reduction strategies. Moreover, virulence potential, rather than simple abundance, should be also be included in future modeling efforts.

  19. Flow cytometry as a tool to quantify oyster defence mechanisms.

    PubMed

    Goedken, Michael; De Guise, Sylvain

    2004-04-01

    The fast growing oyster aquaculture industry is greatly hindered by Perkinsus marinus and Haplosporidium nelsoni which can kill up to 80% of the production. The relationship between parasites and oyster defence mechanisms is unclear. Two defence mechanisms of the Eastern Oyster (Crassostrea virginica) were quantified at the single cell level utilising flow cytometry. Phagocytosis was measured using fluorescent beads. Respiratory burst activity was quantified as the H2O2-specific increase in dichlorofluorescein-associated fluorescence upon stimulation. These two assays distinguished three populations of haemocytes (granulocytes, hyalinocytes and intermediate cells) with unique functional characteristics. Granulocytes were most active at phagocytosis and H2O2 production while hyalinocytes were relatively inactive. The intermediate cells had moderate phagocytic and respiratory burst activity. Flow cytometry can rapidly, accurately and directly quantify the morphology and function of a large number of individual cells, and will lead to a better understanding of the bivalve immune system.

  20. Histopathology of oedema in pearl oysters Pinctada maxima.

    PubMed

    Jones, J B; Crockford, M; Creeper, J; Stephens, F

    2010-07-26

    In October 2006, severe mortalities (80 to 100%) were reported in pearl oyster Pinctada maxima production farms from Exmouth Gulf, Western Australia. Only P. maxima were affected; other bivalves including black pearl oysters P. margaratifera remained healthy. Initial investigations indicated that the mortality was due to an infectious process, although no disease agent has yet been identified. Gross appearance of affected oysters showed mild oedema, retraction of the mantle, weakness and death. Histology revealed no inflammatory response, but we did observe a subtle lesion involving tissue oedema and oedematous separation of epithelial tissues from underlying stroma. Oedema or a watery appearance is commonly reported in published descriptions of diseased molluscs, yet in many cases the terminology has been poorly characterised. The potential causes of oedema are reviewed; however, the question remains as to what might be the cause of oedema in molluscs that are normally iso-osmotic with seawater and have no power of anisosmotic extracellular osmotic regulation.

  1. Vibrio bacteria in raw oysters: managing risks to human health

    PubMed Central

    Froelich, Brett A.; Noble, Rachel T.

    2016-01-01

    The human-pathogenic marine bacteria Vibrio vulnificus and V. parahaemolyticus are strongly correlated with water temperature, with concentrations increasing as waters warm seasonally. Both of these bacteria can be concentrated in filter-feeding shellfish, especially oysters. Because oysters are often consumed raw, this exposes people to large doses of potentially harmful bacteria. Various models are used to predict the abundance of these bacteria in oysters, which guide shellfish harvest policy meant to reduce human health risk. Vibrio abundance and behaviour varies from site to site, suggesting that location-specific studies are needed to establish targeted risk reduction strategies. Moreover, virulence potential, rather than simple abundance, should be also be included in future modeling efforts. PMID:26880841

  2. Guidelines for evaluating performance of oyster habitat restoration

    USGS Publications Warehouse

    Baggett, Lesley P.; Powers, Sean P.; Brumbaugh, Robert D.; Coen, Loren D.; DeAngelis, Bryan M.; Greene, Jennifer K.; Hancock, Boze T.; Morlock, Summer M.; Allen, Brian L.; Breitburg, Denise L.; Bushek, David; Grabowski, Jonathan H.; Grizzle, Raymond E.; Grosholz, Edwin D.; LaPeyre, Megan K.; Luckenbach, Mark W.; McGraw, Kay A.; Piehler, Michael F.; Westby, Stephanie R.; zu Ermgassen, Philine S. E.

    2015-01-01

    Restoration of degraded ecosystems is an important societal goal, yet inadequate monitoring and the absence of clear performance metrics are common criticisms of many habitat restoration projects. Funding limitations can prevent adequate monitoring, but we suggest that the lack of accepted metrics to address the diversity of restoration objectives also presents a serious challenge to the monitoring of restoration projects. A working group with experience in designing and monitoring oyster reef projects was used to develop standardized monitoring metrics, units, and performance criteria that would allow for comparison among restoration sites and projects of various construction types. A set of four universal metrics (reef areal dimensions, reef height, oyster density, and oyster size–frequency distribution) and a set of three universal environmental variables (water temperature, salinity, and dissolved oxygen) are recommended to be monitored for all oyster habitat restoration projects regardless of their goal(s). In addition, restoration goal-based metrics specific to four commonly cited ecosystem service-based restoration goals are recommended, along with an optional set of seven supplemental ancillary metrics that could provide information useful to the interpretation of prerestoration and postrestoration monitoring data. Widespread adoption of a common set of metrics with standardized techniques and units to assess well-defined goals not only allows practitioners to gauge the performance of their own projects but also allows for comparison among projects, which is both essential to the advancement of the field of oyster restoration and can provide new knowledge about the structure and ecological function of oyster reef ecosystems.

  3. Freshwater Detention by Oyster Reefs: Quantifying a Keystone Ecosystem Service

    PubMed Central

    Olabarrieta, Maitane; Frederick, Peter; Valle-Levinson, Arnoldo

    2016-01-01

    Oyster reefs provide myriad ecosystem services, including water quality improvement, fisheries and other faunal support, shoreline protection from erosion and storm surge, and economic productivity. However, their role in directing flow during non-storm conditions has been largely neglected. In regions where oyster reefs form near the mouth of estuarine rivers, they likely alter ocean-estuary exchange by acting as fresh water “dams”. We hypothesize that these reefs have the potential to detain fresh water and influence salinity over extensive areas, thus providing a “keystone” ecosystem service by supporting estuarine functions that rely on the maintenance of estuarine (i.e., brackish) conditions in the near-shore environment. In this work, we investigated the effects of shore-parallel reefs on estuarine salinity using field data and hydrodynamic modeling in a degraded reef complex in the northeastern Gulf of Mexico. Results suggested that freshwater detention by long linear chains of oyster reefs plays an important role in modulating salinities, not only in the oysters’ local environment, but over extensive estuarine areas (tens of square kilometers). Field data confirmed the presence of salinity differences between landward and seaward sides of the reef, with long-term mean salinity differences of >30% between sides. Modeled results expanded experimental findings by illustrating how oyster reefs affect the lateral and offshore extent of freshwater influence. In general, the effects of simulated reefs were most pronounced when they were highest in elevation, without gaps, and when riverine discharge was low. Taken together, these results describe a poorly documented ecosystem service provided by oyster reefs; provide an estimate of the magnitude and spatial extent of this service; and offer quantitative information to help guide future oyster reef restoration. PMID:27936184

  4. Proteomic characterization of oyster shell organic matrix proteins (OMP)

    PubMed Central

    Upadhyay, Abhishek; Thiyagarajan, Vengatesen; Tong, Ying

    2016-01-01

    Oysters are economically and ecologically important bivalves, with its calcareous shell and delicious meat. The shell composition is a blend of inorganic crystals and shell proteins that form an organic matrix which protects the soft inner tissue of the oyster. The objective of the study was to compare the composition of organic matrix proteins (OMP) of two phylogenetically related species: the Hong Kong oyster (Crassostrea hongkongensis) and the Portuguese oyster (Crassostrea angulata) which differ in their shell hardness and mechanical properties. C. hongkongensis shells are comparatively stronger than C. angulata. Modern shotgun proteomics has been used to understand the nature of the OMP and the variations observed in the mechanical properties of these two species of oyster shells. After visualizing proteins on the one (1DE) and two-dimensional electrophoresis (2DE) gels, the protein spots and their intensities were compared using PDQuest software and 14 proteins of C. hongkongensis were found to be significantly different (student׳s t-test; p<0.05) when compared to the C. angulata. Furthermore, shell OMP separated on 1DE gels were processed using Triple TOF5600 mass spectrometry and 42 proteins of C. hongkongensis and 37 of C. angulata identified. A Circos based comparative analysis of the shell proteins of both oyster species were prepared against the shell proteome of other shell forming gastropods and molluscs to study the evolutionary conservation of OMP and their function. This comparative proteomics expanded our understating of the molecular mechanism behind the shells having different hardness and mechanical properties. PMID:28246460

  5. Trace metals in oysters and sediments of Botany Bay, Sydney.

    PubMed

    Hayes, W J; Anderson, I J; Gaffoor, M Z; Hurtado, J

    1998-03-05

    Trace metal concentrations (Pb, Cd, Cu and Zn) in Sydney rock oysters (Sacostera commercialis) and sediments (< 53 microns fraction) were determined for six sites in the northern regions of Botany Bay. Levels for lead, cadmium, copper and zinc in oysters ranged (in microgram g-1) from 1.38 to 15.3, 1.81 to 16.3, 56.1 to 212 and 1806 to 2902, respectively. In sediments, levels ranged (in microgram g-1) from 599 to 4081, 3.57 to 91.0, 191 to 1113 and 227 to 1472, respectively. Such values indicated high levels of contamination, especially in the sediments. Indeed, high proportions of the samples displayed metal concentrations that exceeded the prescribed limits for oysters and sediments. No significant correlations in metal concentrations were found between oysters and sediments, suggesting that changes in the sediment metal loading are not solely influencing the levels of bioavailable metal. The results supported the conclusion that different rates and mechanisms of metal accumulation are taking place in the two types of samples. Variability between sites was high, particularly for oysters. Multidimensional scaling identified that the Cooks River (site 3) and La Perouse (site 6) sites were most dissimilar, both to each other as well as to the other four sites. This was a reflection of high contamination in the Cooks River and the generally low levels in the La Perouse reference sample. The configuration was mainly influenced by the sediment parameters, rather than the oyster metal concentrations, indicating the sediment data were better for identifying site similarities. These ordinations provide evidence of the usefulness of multidimensional scaling in elucidating the physico-chemical variability of the sampling sites.

  6. In vivo effects of metaldehyde on Pacific oyster, Crassostrea gigas: comparing hemocyte parameters in two oyster families.

    PubMed

    Moreau, Pierrick; Burgeot, Thierry; Renault, Tristan

    2015-06-01

    Pollutants via run-off into the ocean represent a potential threat to marine organisms, especially bivalves such as oysters living in coastal environments. These organisms filter large volumes of seawater and may accumulate contaminants within their tissues. Pesticide contamination in water could have a direct or indirect toxic action on tissues or cells and could induce alteration of immune system. Bivalve immunity is mainly supported by hemocytes and participates directly by phagocytosis to eliminate pathogens. Some studies have shown that pesticides can reduce immune defences and/or modify genomes in vertebrates and invertebrates. Metaldehyde is used to kill slugs, snails and other terrestrial gastropods. Although metaldehyde has been detected in surface waters, its effects on marine bivalves including the Pacific oyster, Crassostrea gigas, have never been studied. Given the mode of action of this molecule and its targets (molluscs), it could be potentially more toxic to oysters than other pesticides (herbicides, fungicides, insecticides, etc.). Effects of metaldehyde on oyster hemocyte parameters were thus monitored through in vivo experiments based on a short-term exposure. In this work, metaldehyde at 0.1 μg/L, which corresponds to an average concentration detected in the environment, modulated hemocyte activities of Pacific oysters after an in vivo short-term contact. Individuals belonging to two families showed different behaviours for some hemocyte activities after contamination by metaldehyde. These results suggested that effects of pollutants on oysters may differ from an individual to another in relation to genetic diversity. Finally, it appears essential to take an interest in the effects of metaldehyde on a wide variety of aquatic invertebrates including those that have a significant economic impact.

  7. Millennial-scale sustainability of the Chesapeake Bay Native American oyster fishery.

    PubMed

    Rick, Torben C; Reeder-Myers, Leslie A; Hofman, Courtney A; Breitburg, Denise; Lockwood, Rowan; Henkes, Gregory; Kellogg, Lisa; Lowery, Darrin; Luckenbach, Mark W; Mann, Roger; Ogburn, Matthew B; Southworth, Melissa; Wah, John; Wesson, James; Hines, Anson H

    2016-06-07

    Estuaries around the world are in a state of decline following decades or more of overfishing, pollution, and climate change. Oysters (Ostreidae), ecosystem engineers in many estuaries, influence water quality, construct habitat, and provide food for humans and wildlife. In North America's Chesapeake Bay, once-thriving eastern oyster (Crassostrea virginica) populations have declined dramatically, making their restoration and conservation extremely challenging. Here we present data on oyster size and human harvest from Chesapeake Bay archaeological sites spanning ∼3,500 y of Native American, colonial, and historical occupation. We compare oysters from archaeological sites with Pleistocene oyster reefs that existed before human harvest, modern oyster reefs, and other records of human oyster harvest from around the world. Native American fisheries were focused on nearshore oysters and were likely harvested at a rate that was sustainable over centuries to millennia, despite changing Holocene climatic conditions and sea-level rise. These data document resilience in oyster populations under long-term Native American harvest, sea-level rise, and climate change; provide context for managing modern oyster fisheries in the Chesapeake Bay and elsewhere around the world; and demonstrate an interdisciplinary approach that can be applied broadly to other fisheries.

  8. Development and use of an internal standard for oyster herpesvirus 1 detection by PCR.

    PubMed

    Renault, T; Arzul, I; Lipart, C

    2004-10-01

    Oyster samples were examined using a competitive PCR method in order to detect and quantify oyster herpesvirus 1 (OsHV-1) DNA. Quantitation of viral DNA by competitive PCR assay was based on co-amplification of OsHV-1 DNA and a competitor where a known amount of competitor DNA was present in the same reaction mixture. The competitor was engineered so that it differs in length (deletion of 76 base pairs) from the viral DNA. The assay allowed the detection of 1 fg of viral DNA among 0.5 mg of oyster tissues. The method was used to demonstrate the absence of PCR inhibitors in oyster spat ground tissues. PCR inhibition was observed in adult oyster samples when the same tissue preparation procedure was used. On the contrary, classical phenol/chloroform DNA extraction from adult oyster tissues allowed co-amplification of the internal standard competitor and the viral DNA. The method was successfully used to demonstrate the presence of viral DNA in asymptomatic adult oysters. Quantitation of OsHV-1 DNA in infected spat and asymptomatic adult oysters was also carried out. Viral DNA (1.5-325 pg) were detectable in 0.5 mg of oyster tissues in adults. The amounts of viral DNA in infected oyster spat varied from 750 pg to 35 ng per 0.5 mg of ground tissues.

  9. Millennial-scale sustainability of the Chesapeake Bay Native American oyster fishery

    PubMed Central

    Rick, Torben C.; Reeder-Myers, Leslie A.; Hofman, Courtney A.; Breitburg, Denise; Lockwood, Rowan; Henkes, Gregory; Kellogg, Lisa; Lowery, Darrin; Luckenbach, Mark W.; Mann, Roger; Ogburn, Matthew B.; Southworth, Melissa; Wah, John; Wesson, James; Hines, Anson H.

    2016-01-01

    Estuaries around the world are in a state of decline following decades or more of overfishing, pollution, and climate change. Oysters (Ostreidae), ecosystem engineers in many estuaries, influence water quality, construct habitat, and provide food for humans and wildlife. In North America’s Chesapeake Bay, once-thriving eastern oyster (Crassostrea virginica) populations have declined dramatically, making their restoration and conservation extremely challenging. Here we present data on oyster size and human harvest from Chesapeake Bay archaeological sites spanning ∼3,500 y of Native American, colonial, and historical occupation. We compare oysters from archaeological sites with Pleistocene oyster reefs that existed before human harvest, modern oyster reefs, and other records of human oyster harvest from around the world. Native American fisheries were focused on nearshore oysters and were likely harvested at a rate that was sustainable over centuries to millennia, despite changing Holocene climatic conditions and sea-level rise. These data document resilience in oyster populations under long-term Native American harvest, sea-level rise, and climate change; provide context for managing modern oyster fisheries in the Chesapeake Bay and elsewhere around the world; and demonstrate an interdisciplinary approach that can be applied broadly to other fisheries. PMID:27217572

  10. Microbiological Quality and Prevalence of β-Lactam Antibiotic Resistance Genes in Oysters ( Crassostrea rhizophorae ).

    PubMed

    Brandão, Maria Aparecida da RessurreiÇão; Lopes, Amanda Teixeira Sampaio; Neta, Maria Tereza da Silva; de Oliveira, Rhyan Barros Farias; Rezende, Rachel Passos; Albuquerque, George Rêgo; Gonçalves, Verônica Dias; Rodrigues, Dália Dos Prazeres; Boehs, Guisla; Maciel, Bianca Mendes

    2017-03-01

    The microbiological quality of oysters reflects the microbiological quality of their habitats because they are filter feeders. The objective of this study was to assess the bacterial composition of the edible oyster Crassostrea rhizophorae in urban and preserved estuaries. Particularly, we assessed the presence of pathogenic bacteria, investigated antibiotic susceptibility in bacterial isolates, and quantified β-lactam antibiotic resistance genes (blaTEM, blaSHV, and blaKPC) via quantitative PCR of oyster DNA. Our results detected total coliforms, Escherichia coli , and enterobacteria in the oysters from urban estuaries, which is indicative of poor water quality. In addition, our detection of the eaeA and stxA2 virulence genes in 16.7% of E. coli isolates from oysters from this region suggests the presence of multiantibiotic-resistant enteropathogenic and enterohemorrhagic E. coli strains. During periods of low precipitation, increased contamination by E. coli (in winter) and Vibrio parahaemolyticus (in autumn) was observed. In contrast, cultivated oysters inhabiting monitored farms in preserved areas had low levels of bacterial contamination, emphasizing that oyster culture monitoring enhances food quality and makes oysters fit for human consumption. Distinct antibiotic resistance profiles were observed in bacteria isolated from oysters collected from different areas, including resistance to β-lactam antibiotics. The presence of the blaTEM gene in 91.3% of oyster samples indicated that microorganisms in estuarine water conferred the capability to produce β-lactamase. To our knowledge, this is the first study to directly quantify and detect β-lactam antibiotic resistance genes in oysters. We believe our study provides baseline data for bacterial dynamics in estuarine oysters; such knowledge contributes to developing risk assessments to determine the associated hazards and consequences of consuming oysters from aquatic environments containing pathogenic bacteria

  11. Development of thermal-hydraulic analysis capabilities for Oyster creek

    SciTech Connect

    Lee, R.B.

    1987-01-01

    GPU Nuclear (GPUN) has been involved in developing analytical methodologies for Oyster Creek plant thermal-hydraulic response simulation for approx. 15 yr. Plant-system-related transient analysis is being accomplished via RETRAN02 MOD4 and loss-of-coolant accident (LOCA) analysis by SAFER-CORECOOL. This paper reviews the developmental process and lessons learned through this process.

  12. Performance of selected eastern oyster lines across northeastern US estuaries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eastern oyster production derived from aquaculture has expanded, but growth potential is constrained by losses to disease. Breeding programs supporting industry in the Northeast have targeted resistance to three diseases: MSX, Dermo, and ROD. Selected lines should possess some level of resistance a...

  13. Culture and Sustainability: Lessons from the Oyster and Other Metaphors

    ERIC Educational Resources Information Center

    Galloway, Vicki

    2015-01-01

    Consider the oyster. Like all good metaphors, it has done some morphing since the days of Shakespeare's "Merry Wives of Windsor." Newer bands of shell material have repainted the mollusk metaphor, transforming it from ostracism, opportunism, and exploitation to openness, opportunity and exploration, and thus an apt symbol for the…

  14. Active downward propulsion by oyster larvae in turbulence.

    PubMed

    Fuchs, Heidi L; Hunter, Elias J; Schmitt, Erika L; Guazzo, Regina A

    2013-04-15

    Oyster larvae (Crassostrea virginica) could enhance their settlement success by moving toward the seafloor in the strong turbulence associated with coastal habitats. We characterized the behavior of individual oyster larvae in grid-generated turbulence by measuring larval velocities and flow velocities simultaneously using infrared particle image velocimetry. We estimated larval behavioral velocities and propulsive forces as functions of the kinetic energy dissipation rate ε, strain rate γ, vorticity ξ and acceleration α. In calm water most larvae had near-zero vertical velocities despite propelling themselves upward (swimming). In stronger turbulence all larvae used more propulsive force, but relative to the larval axis, larvae propelled themselves downward (diving) instead of upward more frequently and more forcefully. Vertical velocity magnitudes of both swimmers and divers increased with turbulence, but the swimming velocity leveled off as larvae were rotated away from their stable, velum-up orientation in strong turbulence. Diving speeds rose steadily with turbulence intensity to several times the terminal fall velocity in still water. Rapid dives may require a switch from ciliary swimming to another propulsive mode such as flapping the velum, which would become energetically efficient at the intermediate Reynolds numbers attained by larvae in strong turbulence. We expected larvae to respond to spatial or temporal velocity gradients, but although the diving frequency changed abruptly at a threshold acceleration, the variation in propulsive force and behavioral velocity was best explained by the dissipation rate. Downward propulsion could enhance oyster larval settlement by raising the probability of larval contact with oyster reef patches.

  15. Stress-induced immune changes in the oyster Crassostrea gigas.

    PubMed

    Lacoste, Arnaud; Malham, Shelagh K; Gélébart, Florence; Cueff, Anne; Poulet, Serge A

    2002-01-01

    Information concerning the effect of stress on invertebrate immune functions are scarce. The present study investigated the consequences of a 15-min mechanical disturbance on immune parameters in oysters Crassostrea gigas. As indicated by noradrenaline and dopamine measurements, the mechanical disturbance caused a transient state of stress in oysters. The number of circulating hemocytes, the migratory and phagocytic activities and reactive oxygen species production of hemocytes were measured before, during and after application of the stressor. Results show that all immune functions were significantly downregulated during stress and a transient period of immunostimulation was observed 30-240 min after the end of the disturbance. Taken together, these results suggest that stress can exert a profound influence on oyster immune functions and they may explain why stress and the outbreak of disease are often linked in shellfish culture. Furthermore, the present study strongly suggests that checking the stress status of animals may be necessary to avoid biases when studying oyster immune responses in vivo.

  16. Norovirus outbreak associated with undercooked oysters and secondary household transmission.

    PubMed

    Alfano-Sobsey, E; Sweat, D; Hall, A; Breedlove, F; Rodriguez, R; Greene, S; Pierce, A; Sobsey, M; Davies, M; Ledford, S L

    2012-02-01

    During December 2009, over 200 individuals reported gastrointestinal symptoms after dining at a North Carolina restaurant. An outbreak investigation included a case-control study of restaurant patrons, a secondary household transmission study, environmental assessment of the restaurant facilities and operations, and laboratory analysis of stool and food samples. Illness was primarily associated with consumption of steamed oysters (odds ratio 12, 95% confidence interval 4·8-28) and 20% (8/41 households) reported secondary cases, with a secondary attack rate of 14% among the 70 susceptible household contacts. Norovirus RNA was detected in 3/5 stool specimens from ill patrons; sequencing of RT-PCR products from two of these specimens identified identical genogroup II genotype 12 sequences. Final cooked temperatures of the steamed oysters were generally inadequate to inactivate norovirus, ranging from 21°C to 74°C. Undercooked contaminated oysters pose a similar risk for norovirus illness as raw oysters and household contacts are at risk for secondary infection.

  17. Oyster reefs can outpace sea-level rise

    NASA Astrophysics Data System (ADS)

    Rodriguez, Antonio B.; Fodrie, F. Joel; Ridge, Justin T.; Lindquist, Niels L.; Theuerkauf, Ethan J.; Coleman, Sara E.; Grabowski, Jonathan H.; Brodeur, Michelle C.; Gittman, Rachel K.; Keller, Danielle A.; Kenworthy, Matthew D.

    2014-06-01

    In the high-salinity seaward portions of estuaries, oysters seek refuge from predation, competition and disease in intertidal areas, but this sanctuary will be lost if vertical reef accretion cannot keep pace with sea-level rise (SLR). Oyster-reef abundance has already declined ~85% globally over the past 100 years, mainly from over harvesting, making any additional losses due to SLR cause for concern. Before any assessment of reef response to accelerated SLR can be made, direct measures of reef growth are necessary. Here, we present direct measurements of intertidal oyster-reef growth from cores and terrestrial lidar-derived digital elevation models. On the basis of our measurements collected within a mid-Atlantic estuary over a 15-year period, we developed a globally testable empirical model of intertidal oyster-reef accretion. We show that previous estimates of vertical reef growth, based on radiocarbon dates and bathymetric maps, may be greater than one order of magnitude too slow. The intertidal reefs we studied should be able to keep up with any future accelerated rate of SLR (ref. ) and may even benefit from the additional subaqueous space allowing extended vertical accretion.

  18. An improved method for quantification of Vibrio vulnificus in oysters.

    PubMed

    Cruz, C D; Win, J K; Fletcher, G C

    2013-12-01

    Chromogenic agar was compared with the FDA recommended cellobiose-colistin agar for assessment of Vibrio vulnificus in oysters. A two-step culture confirmation method was also evaluated. The inclusion of CA gave a 33% increase in the detection rate and the two-step culture confirmation eliminated 62.5% of false positives.

  19. Study of atrazine effects on Pacific oyster, Crassostrea gigas, haemocytes.

    PubMed

    Gagnaire, B; Renault, T; Bouilly, K; Lapegue, S; Thomas-Guyon, H

    2003-01-01

    Shellfish farming is an important economic activity around the world. This activity often takes place in areas subjected to various recurring pollutions. The recrudescent use of herbicides in agriculture including atrazine implies pollutant transfer towards aquatic environment in estuarine areas. Harmful effects of such substances on animals in marine environment, particularly on cultured bivalves, are poorly documented. Bivalve molluscs such as mussels and oysters have been postulated as ideal indicator organisms because of their way of life. They filter large volumes of seawater and may therefore accumulate and concentrate contaminants within their tissues. Moreover, development of techniques allowing effect analysis of such compounds on bivalve biology may lead to the development of diagnosis tools adapted to analyze pollutant transfer towards estuarine areas. In this context, influence of atrazine on defence mechanisms was analyzed in Pacific oysters, Crassostrea gigas. Atrazine was tested in vitro and in vivo on oyster haemocytes, and its effects were analyzed by flow cytometry. Haemocyte viability, cell cycle and cellular activities were monitored. Atrazine induced no significant effect in oyster under tested conditions except for peroxidase activity.

  20. Detection of Salmonella spp. in oysters by PCR.

    PubMed Central

    Bej, A K; Mahbubani, M H; Boyce, M J; Atlas, R M

    1994-01-01

    PCR DNA amplification of a region of the himA gene of Salmonella typhimurium specifically detected Salmonella spp. In oysters, 1 to 10 cells of Salmonella spp. were rapidly detected by the PCR following a pre-enrichment step to increase sensitivity and to ensure that detection was based on the presence of viable Salmonella spp. Images PMID:8117091

  1. OYSTER HABITAT SUITABILITY AS A COMPONENT OF RESOURCE MANAGEMENT

    EPA Science Inventory

    Economic and ecological issues have led resource managers to examine depletion of eastern oyster reefs along the U.S. Gulf of Mexico and Atlantic coasts. Crassostrea virginica is a lucrative commercial species (over $60M in 2000) that also supports ecosystem integrity by providin...

  2. FISHERY-ORIENTED MODEL OF MARYLAND OYSTER POPULATIONS

    EPA Science Inventory

    We used time series data to calibrate a model of oyster population dynamics for Maryland's Chesapeake Bay. Model parameters were fishing mortality, natural mortality, recruitment, and carrying capacity. We calibrated for the Maryland bay as a whole and separately for 3 salinity z...

  3. High pressure processing inactivates human norovirus within oysters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Consumption of raw bivalve mollusks can result in norovirus infection. One potential intervention for virus-contaminated shellfish is high pressure processing (HPP). Currently HPP is known to inactivate Vibrio bacteria, hepatitis A virus, and murine norovirus within oysters. To evaluate the potentia...

  4. Antimicrobial peptides in oyster hemolymph: the bacterial connection.

    PubMed

    Defer, Diane; Desriac, Florie; Henry, Joël; Bourgougnon, Nathalie; Baudy-Floc'h, Michèle; Brillet, Benjamin; Le Chevalier, Patrick; Fleury, Yannick

    2013-06-01

    We have explored antimicrobial compounds in oyster hemolymph and purified four active peptides with molecular masses of 4464, 3158, 655 and 636 Da. While no exploitable structural elements were obtained for the former three, a partial amino acid sequence (X-P-P-X-X-I-V) was obtained for the latter, named Cg-636. Due to both its low MM and the presence of exotic amino acid residue (X), we suspected a bacterial origin and tracked cultivable hemolymph-resident bacteria of oyster for their antimicrobial abilities. Supernatants of 224 hemolymph resident bacteria coming from 60 oysters were screened against 10 target bacteria including aquaculture pathogens. Around 2% (5 strains) revealed antimicrobial activities. They belong to Pseudoalteromonas and Vibrio genera. Two closely related strains named hCg-6 and hCg-42 have been shown to produce Bacteriocin-Like Inhibitory Substances (BLIS) even in oyster hemolymph. We report herein first BLIS-producing bacteria isolated from bivalve hemolymph. These results strongly suggest that hemolymph resident bacteria may prevent pathogen establishment and pave the way for considering a role of resident bacteria into bivalve defense.

  5. Molecular detection of Marteilia sydneyi, pathogen of Sydney rock oysters.

    PubMed

    Kleeman, S N; Adlard, R D

    2000-03-14

    The life cycle of Marteilia sydneyi, the aetiological agent of QX disease in the Sydney rock oyster Saccostrea commercialis, is not known. We have developed and optimised 2 diagnostic assays, the polymerase chain reaction (PCR) and in situ hybridisation, for use in investigating the role of possible alternative hosts in the life cycle of this pathogen. PCR primers, designed within the ITS1 rDNA of M. sydneyi, amplified a 195 bp fragment. Sensitivity of the PCR assay was assessed using DNA extracted from known numbers of sporonts purified from infected oyster digestive gland. DNA equivalent to 0.01 sporonts was detectable following agarose gel electrophoresis. The potential inhibitory effect of the presence of host DNA on the PCR assay was tested by the addition of oyster genomic DNA during amplification. Concentrations of host DNA in excess of 50 ng per 20 microliters reaction reduced the sensitivity of the test. Environmental validation of the PCR assay was demonstrated by the amplification of M. sydneyi DNA from 50 ng of genomic DNA extracted from QX-infected oysters. A DNA probe was constructed using the M. sydneyi unique primers and was able to detect 10 pg of M. sydneyi PCR amplified DNA in dot-blot hybridisations. The probe hybridised with presporulating and sporulating M. sydneyi stages in paraffin sections of oyster digestive gland. No non-specific binding was observed. Hybridisation consistency and signal intensity decreased as sporonts matured. While the high sensitivity and specificity of the PCR test will allow rapid screening of large numbers of potential alternative hosts for the presence of parasite DNA, it does not actually identify infective stages. In situ hybridisation conducted on paraffin sections will determine the location of the parasite within the host for morphological characterisation.

  6. Latitudinal gradients in ecosystem engineering by oysters vary across habitats.

    PubMed

    McAfee, Dominic; Cole, Victoria J; Bishop, Melanie J

    2016-04-01

    Ecological theory predicts that positive interactions among organisms will increase across gradients of increasing abiotic stress or consumer pressure. This theory has been supported by empirical studies examining the magnitude of ecosystem engineering across environmental gradients and between habitat settings at local scale. Predictions that habitat setting, by modifying both biotic and abiotic factors, will determine large-scale gradients in ecosystem engineering have not been tested, however. A combination of manipulative experiments and field surveys assessed whether along the east Australian coastline: (1) facilitation of invertebrates by the oyster Saccostrea glomerata increased across a latitudinal gradient in temperature; and (2) the magnitude of this effect varied between intertidal rocky shores and mangrove forests. It was expected that on rocky shores, where oysters are the primary ecosystem engineer, they would play a greater role in ameliorating latitudinal gradients in temperature than in mangroves, where they are a secondary ecosystem engineer living under the mangrove canopy. On rocky shores, the enhancement of invertebrate abundance in oysters as compared to bare microhabitat decreased with latitude, as the maximum temperatures experienced by intertidal organisms diminished. By contrast, in mangrove forests, where the mangrove canopy resulted in maximum temperatures that were cooler and of greater humidity than on rocky shores, we found no evidence of latitudinal gradients of oyster effects on invertebrate abundance. Contrary to predictions, the magnitude by which oysters enhanced biodiversity was in many instances similar between mangroves and rocky shores. Whether habitat-context modifies patterns of spatial variation in the effects of ecosystem engineers on community structure will depend, in part, on the extent to which the environmental amelioration provided by an ecosystem engineer replicates that of other co-occurring ecosystem engineers.

  7. Experimental infection of Pacific oyster Crassostrea gigas spat by ostreid herpesvirus 1: demonstration of oyster spat susceptibility.

    PubMed

    Schikorski, David; Renault, Tristan; Saulnier, Denis; Faury, Nicole; Moreau, Pierrick; Pépin, Jean-François

    2011-02-07

    In 2008 and 2009, acute mortalities occurred in France among Pacific cupped oyster, Crassostrea gigas, spat. Different hypothesis including the implication of environmental factors, toxic algae and/or pathogens have been explored. Diagnostic tests indicated that OsHV-1 including a particular genotype, termed OsHV-1 μVar, was detected in most of samples and especially in moribund oysters with the highlighting of virus particles looking like herpes viruses by TEM examination. In this study, an experimental protocol to reproduce OsHV-1 infection in laboratory conditions was developed. This protocol was based on the intramuscular injection of filtered (0.22 μm) tissue homogenates prepared from naturally OsHV-1 infected spat collected on French coasts during mortality outbreaks in 2008. Results of the experimental trials showed that mortalities were induced after injection. Moreover, filtered tissue homogenates induced mortalities whereas the same tissue homogenates exposed to an ultraviolet (UV) treatment did not induce any mortality suggesting that oyster spat mortalities require the presence of a UV sensitive agent. Furthermore, analysis of injected oyster spat revealed the detection of high amounts of OsHV-1 DNA by real-time quantitative PCR. Finally, TEM analysis demonstrated the presence of herpes virus particles. The developed protocol allowed to maintain sources of infective virus which can be useful for the development of further studies concerning the transmission and the development of OsHV-1 infection.

  8. Experimental infection of Pacific oyster Crassostrea gigas spat by ostreid herpesvirus 1: demonstration of oyster spat susceptibility

    PubMed Central

    2011-01-01

    In 2008 and 2009, acute mortalities occurred in France among Pacific cupped oyster, Crassostrea gigas, spat. Different hypothesis including the implication of environmental factors, toxic algae and/or pathogens have been explored. Diagnostic tests indicated that OsHV-1 including a particular genotype, termed OsHV-1 μVar, was detected in most of samples and especially in moribund oysters with the highlighting of virus particles looking like herpes viruses by TEM examination. In this study, an experimental protocol to reproduce OsHV-1 infection in laboratory conditions was developed. This protocol was based on the intramuscular injection of filtered (0.22 μm) tissue homogenates prepared from naturally OsHV-1 infected spat collected on French coasts during mortality outbreaks in 2008. Results of the experimental trials showed that mortalities were induced after injection. Moreover, filtered tissue homogenates induced mortalities whereas the same tissue homogenates exposed to an ultraviolet (UV) treatment did not induce any mortality suggesting that oyster spat mortalities require the presence of a UV sensitive agent. Furthermore, analysis of injected oyster spat revealed the detection of high amounts of OsHV-1 DNA by real-time quantitative PCR. Finally, TEM analysis demonstrated the presence of herpes virus particles. The developed protocol allowed to maintain sources of infective virus which can be useful for the development of further studies concerning the transmission and the development of OsHV-1 infection. PMID:21314910

  9. ["Non-aging" pearl oyster and aging salmon (about lack of basis for production of medicines based on European pearl oyster Margaritifera margaritifera)].

    PubMed

    Popov, I Iu

    2009-01-01

    The article focuses on disproof of the claim by Valery Ziuganov, that pearl oyster infection prolongs the lifespan of salmon and that pearl oyster can be used as a source of medicine. His activity on the production of medicine pretending to care cancer and senescence based on the gills of salmon infected by pearl oyster is blamed. The data on pearl oyster and salmon biology are presented: Atlantic salmon survives after spawning irrespectively of oyster infection. The problem of shady medicines production is discussed. It was shown that even Academic editions and formal attributes of the belonging to scientific community do not provide a necessary barrier to frauds in this field. Adaptationist program popularity contributes such a situation, because it provides "grounds" for any speculation concerning advantages of any biological process.

  10. Molecular Basis for Adaptation of Oysters to Stressful Marine Intertidal Environments.

    PubMed

    Zhang, Guofan; Li, Li; Meng, Jie; Qi, Haigang; Qu, Tao; Xu, Fei; Zhang, Linlin

    2016-01-01

    Oysters that occupy estuarine and intertidal habitats have well-developed stress tolerance mechanisms to tolerate harsh and dynamically changing environments. In this review, we summarize common pathways and genomic features in oyster that are responsive to environmental stressors such as temperature, salinity, hypoxia, air exposure, pathogens, and anthropogenic pollutions. We first introduce the key genes involved in several pathways, which constitute the molecular basis for adaptation to stress. We use genome analysis to highlight the strong cellular homeostasis system, a unique adaptive characteristic of oysters. Next, we provide a global view of features of the oyster genome that contribute to stress adaptation, including oyster-specific gene expansion, highly inducible expression, and functional divergence. Finally, we review the consequences of interactions between oysters and the environment from ecological and evolutionary perspectives by discussing mass mortality and adaptive divergence among populations and related species of the genus Crassostrea. We conclude with prospects for future study.

  11. The recovery of oyster (Saccostrea glomerata) populations in Sydney estuary (Australia).

    PubMed

    Birch, G F; Scammell, M S; Besley, C H

    2014-01-01

    The current work documented a significant and widespread increase in the abundance of the Sydney rock oyster Saccostrea glomerata, in Sydney estuary (Australia) by undertaking surveys of oyster density in the estuary in 1989 and annually from 1994 to 2006. Oyster density at six control sites located in nearby National Parks unaffected by boating and stormwater discharges were compared to 17 study sites widely distributed within Sydney estuary. No oyster populations were evident in Sydney estuary in 1989; however, by 1994 oysters had colonised areas of the lower and central estuary and by 2002 densities were statistically similar to control sites. The timing of estuary-wide increases in oyster abundance suggests that the partial banning of tributyltin in 1989 for vessels under 25 m long may have played a major role in the increase of S. glomerata in this estuary.

  12. Influence of eutrophication on metal bioaccumulation and oral bioavailability in oysters, Crassostrea angulata.

    PubMed

    Li, Shun-Xing; Chen, Li-Hui; Zheng, Feng-Ying; Huang, Xu-Guang

    2014-07-23

    Oysters (Crassostrea angulata) are often exposed to eutrophication. However, how these exposures influence metal bioaccumulation and oral bioavailability (OBA) in oysters is unknown. After a four month field experimental cultivation, bioaccumulation factors (BAF) of metals (Fe, Cu, As, Cd, and Pb) from seawater to oysters and metal oral bioavailability in oysters by bionic gastrointestinal tract were determined. A positive effect of macronutrient (nitrate N and total P) concentration in seawater on BAF of Cd in oysters was observed, but such an effect was not significant for Fe, Cu, Pb, and As. Only OBA of As was significantly positively correlated to N and P contents. For Fe, OBA was negatively correlated with N. The regular variation of the OBA of Fe and As may be due to the effect of eutrophication on the synthesis of metal granules and heat-stable protein in oysters, respectively.

  13. Ocean acidification increases the vulnerability of native oysters to predation by invasive snails.

    PubMed

    Sanford, Eric; Gaylord, Brian; Hettinger, Annaliese; Lenz, Elizabeth A; Meyer, Kirstin; Hill, Tessa M

    2014-03-07

    There is growing concern that global environmental change might exacerbate the ecological impacts of invasive species by increasing their per capita effects on native species. However, the mechanisms underlying such shifts in interaction strength are poorly understood. Here, we test whether ocean acidification, driven by elevated seawater pCO₂, increases the susceptibility of native Olympia oysters to predation by invasive snails. Oysters raised under elevated pCO₂ experienced a 20% increase in drilling predation. When presented alongside control oysters in a choice experiment, 48% more high-CO₂ oysters were consumed. The invasive snails were tolerant of elevated CO₂ with no change in feeding behaviour. Oysters raised under acidified conditions did not have thinner shells, but were 29-40% smaller than control oysters, and these smaller individuals were consumed at disproportionately greater rates. Reduction in prey size is a common response to environmental stress that may drive increasing per capita effects of stress-tolerant invasive predators.

  14. Characterization studies on the cadmium-binding proteins from two species of New Zealand oysters

    SciTech Connect

    Nordberg, M.; Nuottaniemi, I.; Cherian, M.G.; Nordberg, G.F.; Kjellstroem, T.; Garvey, J.S.

    1986-03-01

    Two different types of New Zealand oysters - Ostrea lutaria (OL) and Crassostrea glomerata (CG) - contained different concentrations of zinc, copper, and cadmium. Both kinds of oysters were shown by gel filtration (G-75) to contain cadmium and zinc in fractions corresponding to a high molecular weight protein which was heat labile. OL oysters contained cadmium in fractions corresponding to a molecular weight of approximately 6500. The cadmium-binding protein in these fractions was heat-stable. This protein contained no detectable amounts of zinc and was not present in the CG oysters. CG oysters contained cadmium and zinc in a polypeptide with low molecular weight (MW 1000). The cadmium-binding oyster proteins are minimally reactive in a competitive binding radioimmunoassay in comparison to the reactivity of a typical vertebrate metallothionein; the proteins may be metallothioneins, but, if so, they do not exhibit the principal determinants characteristic of vertebrate metallothioneins.

  15. Benthic surveys of the historic pearl oyster beds of Qatar reveal a dramatic ecological change.

    PubMed

    Smyth, D; Al-Maslamani, I; Chatting, M; Giraldes, B

    2016-12-15

    The study aimed to confirm the presence of historic oyster banks of Qatar and code the biotopes present. The research also collated historical records and scientific publications to create a timeline of fishery activity. The oyster banks where once an extremely productive economic resource however, intense overfishing, extreme environmental conditions and anthropogenic impacts caused a fishery collapse. The timeline highlighted the vulnerability of ecosystem engineering bivalves if overexploited. The current status of the oyster banks meant only one site could be described as oyster dominant. This was unexpected as the sites were located in areas which once supported a highly productive oyster fishery. The research revealed the devastating effect that anthropogenic impacts can have on a relatively robust marine habitat like an oyster bed and it is hoped these findings will act as a driver to investigate and map other vulnerable habitats within the region before they too become compromised.

  16. Pearl oysters Pinctada margaritifera grazing on natural plankton in Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia).

    PubMed

    Fournier, Jonathan; Dupuy, Christine; Bouvy, Marc; Couraudon-Réale, Marine; Charpy, Loïc; Pouvreau, Stephane; Le Moullac, Gilles; Le Pennec, Marcel; Cochard, Jean-Claude

    2012-01-01

    In atoll lagoons of French Polynesia, growth and reproduction of pearl oysters are mainly driven by plankton concentration. However, the actual diet of black-lip pearl oysters Pinctada margaritifera in these lagoons is poorly known. To fill this gap, we used the flow through chamber method to measure clearance rates of P. margaritifera in Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia). We found: (i) that pearl oysters cleared plankton at a rate that was positively related to plankton biovolume, (ii) that nanoflagellates were the main source of carbon for the pearl oysters, and (iii) that the quantity and origin of carbon filtrated by pearl oysters was highly dependent on the concentration and composition of plankton. These results provide essential elements for the comprehension of growth and reproduction variability of pearl oysters in atoll lagoons of French Polynesia.

  17. A comparative proteomic study on the effects of metal pollution in oysters Crassostrea hongkongensis.

    PubMed

    Xu, Lanlan; Ji, Chenglong; Wu, Huifeng; Tan, Qiaoguo; Wang, Wen-Xiong

    2016-11-15

    The metal pollution has posed great risk on the coastal organisms along the Jiulongjiang Estuary in South China. In this work, two-dimensional electrophoresis-based proteomics was applied to the oysters Crassostrea hongkongensis from metal pollution sites to characterize the proteomic responses to metal pollution. Metal accumulation and proteomic responses indicated that the oysters from BJ site were more severely contaminated than those from FG site. Compared with those oyster samples from the clean site (JZ), metal pollution induced cellular injuries, oxidative and immune stresses in oyster heapatopancreas from both BJ and FG sites via differential metabolic pathways. In addition, metal pollution in BJ site induced disturbance in energy and lipid metabolisms in oysters. Results indicated that cathepsin L and ferritin GF1 might be the biomarkers of As and Fe in oyster C. hongkongensis, respectively. This study demonstrates that proteomics is a useful tool for investigating biological effects induced by metal pollution.

  18. Effect of parasitism by the pyramidellid gastropod Boonea impressa on the net productivity of oysters ( Crassostrea virginica)

    NASA Astrophysics Data System (ADS)

    White, M. E.; Powell, E. N.; Ray, S. M.

    1988-04-01

    The effect of an ectoparasitic gastropod, Boonea (= Odostomia) impressa, on the energy bidget of its host, the American oyster, Crassostrea virginica, was examined. A model was developed from laboratory and field data, as well as from equations developed by Powell and Stanton (1985). The model predicted that net productivity by large (7 cm length) oysters parasitized by 10 and 30 large (6 mm length) snails would be reduced by 21% and 63%, respectively. In contrast, net productivity in small (3 cm length) oysters would be reduced 25% by only 3 snails. Small oysters would have a negative energy balance when parasitized by 10 snails. The predicted reduction in growth was compared with measured growth in small and large oysters parasitized at abundances typical of Texas oyster reefs. Control oysters (no parasites) gained more shell weight than parasitized oysters. In four-week experiments conducted during the spring and fall, small control oysters gained 86% and 75% more weight than highly parasitized oysters. Large control oysters had 29% and 88% more shell deposition. Snail parasitism produced 75% mortality in small, highly parasitized oysters in the summer. In typical field populations in Texas bays, a minimal estimate of 4-12% of the energy otherwise available to the oyster for growth and reproduction is consumed by Boonea impressa.

  19. Hemolymph chemistry and histopathological changes in Pacific oysters (Crassostrea gigas) in response to low salinity stress.

    PubMed

    Knowles, Graeme; Handlinger, Judith; Jones, Brian; Moltschaniwskyj, Natalie

    2014-09-01

    This study described seasonal differences in the histopathological and hemolymph chemistry changes in different family lines of Pacific oysters, Crassostrea gigas, in response to the stress of an abrupt change to low salinity, and mechanical grading. The most significant changes in pallial cavity salinity, hemolymph chemistry and histopathological findings occurred in summer at low salinity. In summer (water temperature 18°C) at low salinity, 9 (25.7% of full salinity), the mean pallial cavity salinity in oysters at day 3 was 19.8±1.6 (SE) and day 10 was 22.8±1.6 (SE) lower than oysters at salinity 35. Associated with this fall in pallial cavity salinity, mean hemolymph sodium for oysters at salinity 9 on day 3 and 10 were 297.2mmol/L±20(SE) and 350.4mmol/L±21.3(SE) lower than oysters at salinity 35. Similarly mean hemolymph potassium in oysters held at salinity 9 at day 3 and 10 were 5.6mmol/L±0.6(SE) and 7.9mmol/L±0.6 (SE) lower than oysters at salinity 35. These oysters at low salinity had expanded intercellular spaces and significant intracytoplasmic vacuolation distending the cytoplasm of epithelial cells in the alimentary tract and kidney and hemocyte infiltrate (diapedesis) within the alimentary tract wall. In contrast, in winter (water temperature 8°C) oyster mean pallial cavity salinity only fell at day 10 and this was by 6.0±0.6 (SE) compared to that of oysters at salinity 35. There were limited histopathological changes (expanded intercellular spaces and moderate intracytoplasmic vacuolation of renal epithelial cells) in these oysters at day 10 in low salinity. Mechanical grading and family line did not influence the oyster response to sudden low salinity. These findings provide additional information for interpretation of non-lethal, histopathological changes associated with temperature and salinity variation.

  20. Bistability in a differential equation model of oyster reef height and sediment accumulation.

    PubMed

    Jordan-Cooley, William C; Lipcius, Romuald N; Shaw, Leah B; Shen, Jian; Shi, Junping

    2011-11-21

    Native oyster populations in Chesapeake Bay have been the focus of three decades of restoration attempts, which have generally failed to rebuild the populations and oyster reef structure. Recent restoration successes and field experiments indicate that high-relief reefs persist, likely due to elevated reef height which offsets heavy sedimentation and promotes oyster survival, disease resistance and growth, in contrast to low-relief reefs which degrade in just a few years. These findings suggest the existence of alternative stable states in oyster reef populations. We developed a mathematical model consisting of three differential equations that represent volumes of live oysters, dead oyster shells (=accreting reef), and sediment. Bifurcation analysis and numerical simulations demonstrated that multiple nonnegative equilibria can exist for live oyster, accreting reef and sediment volume at an ecologically reasonable range of parameter values; the initial height of oyster reefs determined which equilibrium was reached. This investigation thus provides a conceptual framework for alternative stable states in native oyster populations, and can be used as a tool to improve the likelihood of success in restoration efforts.

  1. Inhibition of 4NQO-Induced Oral Carcinogenesis by Dietary Oyster Shell Calcium.

    PubMed

    Chen, Ying; Jiang, Yi; Liao, Liyan; Zhu, Xiaoxin; Tang, Shengan; Yang, Qing; Sun, Lihua; Li, Yujie; Gao, Shuangrong; Xie, Zhongjian

    2016-03-01

    Oyster has gained much attention recently for its anticancer activity but it is unclear whether calcium, the major antitumor ingredient in oyster shell, is responsible for the anticarcinogenic role of the oyster. To address this issue, C57BL/6 mice were fed with the carcinogen 4-nitroquinoline-1-oxide (4NQO, 50 µg/mL) and normal diet or a diet containing oyster powder, oyster calcium, or calcium depleted oyster powder. The tongue tissue specimens isolated from these mice were histologically evaluated for hyperplasia, dysplasia, and papillary lesions, and then analyzed for proliferation and differentiation markers by immunohistochemistry. The results showed that mice on the diet containing oyster calcium significantly reduced rates of tumors in the tongue and proliferation and enhanced differentiation in the oral epithelium compared with the diet containing calcium depleted oyster powder. These results suggest that calcium in oyster plays a critical role in suppressing formation of oral squamous cell carcinoma and proliferation and promoting differentiation of the oral epithelium.

  2. Investigations of Salmonella enterica serovar newport infections of oysters by using immunohistochemistry and knockout mutagenesis.

    PubMed

    Morrison, Christopher M; Dial, Sharon M; Day, William A; Joens, Lynn A

    2012-04-01

    The consumption of raw oysters is an important risk factor in the acquisition of food-borne disease, with Salmonella being one of a number of pathogens that have been found in market oysters. Previous work by our lab found that Salmonella was capable of surviving in oysters for over 2 months under laboratory conditions, and this study sought to further investigate Salmonella's tissue affinity and mechanism of persistence within the oysters. Immunohistochemistry was used to show that Salmonella was capable of breaching the epithelial barriers, infecting the deeper connective tissues of the oysters, and evading destruction by the oysters' phagocytic hemocytes. To further investigate the mechanism of these infections, genes vital to the function of Salmonella's two main type III secretion systems were disrupted and the survivability of these knockout mutants within oysters was assayed. When the Salmonella pathogenicity island 1 and 2 mutant strains were exposed to oysters, there were no detectable deficiencies in their abilities to survive, suggesting that Salmonella's long-term infection of oysters does not rely upon these two important pathogenicity islands and must be due to some other, currently unknown, mechanism.

  3. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Northwest): Olympia oyster

    SciTech Connect

    Couch, D. . Coll. of Natural Resources); Hassler, T.J. . California Cooperative Fishery Research Unit)

    1989-12-01

    Species profiles are literature summaries of the taxonomy, morphology, range, life history, and environmental requirements of coastal aquatic species. They are designed to assist in environmental impact assessments. Olympia oysters initially spawn as males then alternate their functional genders. Spawning begins at 13-16 {degree}C and occurs from spring to fall. After a short planktonic stage, larvae attach to the substrate. Olympia oysters thrive at salinities of 25 ppt or above; they are killed by freezing temperatures. Olympia oysters once supported large sustenance and commercial fisheries. Olympia oysters have not returned to pre-exploitation population levels which declined because of pollution and loss of habitat. 32 refs., 2 figs.

  4. Exploring spatial and temporal variations of cadmium concentrations in pacific oysters from british columbia.

    PubMed

    Feng, Cindy Xin; Cao, Jiguo; Bendell, Leah

    2011-09-01

    Oysters from the Pacific Northwest coast of British Columbia, Canada, contain high levels of cadmium, in some cases exceeding some international food safety guidelines. A primary goal of this article is the investigation of the spatial and temporal variation in cadmium concentrations for oysters sampled from coastal British Columbia. Such information is important so that recommendations can be made as to where and when oysters can be cultured such that accumulation of cadmium within these oysters is minimized. Some modern statistical methods are applied to achieve this goal, including monotone spline smoothing, functional principal component analysis, and semi-parametric additive modeling. Oyster growth rates are estimated as the first derivatives of the monotone smoothing growth curves. Some important patterns in cadmium accumulation by oysters are observed. For example, most inland regions tend to have a higher level of cadmium concentration than most coastal regions, so more caution needs to be taken for shellfish aquaculture practices occurring in the inland regions. The semi-parametric additive modeling shows that oyster cadmium concentration decreases with oyster length, and oysters sampled at 7 m have higher average cadmium concentration than those sampled at 1 m.

  5. Increased temperatures combined with lowered salinities differentially impact oyster size class growth and mortality

    USGS Publications Warehouse

    LaPeyre, Megan K.; Rybovich, Molly; Hall, Steven G.; La Peyre, Jerome F.

    2016-01-01

    Changes in the timing and interaction of seasonal high temperatures and low salinities as predicted by climate change models could dramatically alter oyster population dynamics. Little is known explicitly about how low salinity and high temperature combinations affect spat (<25mm), seed (25–75mm), andmarket (>75mm) oyster growth and mortality. Using field and laboratory studies, this project quantified the combined effects of extremely low salinities (<5) and high temperatures (>30°C) on growth and survival of spat, seed, andmarket-sized oysters. In 2012 and 2013, hatchery-produced oysters were placed in open and closed cages at three sites in Breton Sound, LA, along a salinity gradient that typically ranged from 5 to 20. Growth and mortality were recorded monthly. Regardless of size class, oysters at the lowest salinity site (annualmean = 4.8) experienced significantly highermortality and lower growth than oysters located in higher salinity sites (annual means = 11.1 and 13.0, respectively); furthermore, all oysters in open cages at the two higher salinity sites experienced higher mortality than in closed cages, likely due to predation. To explicitly examine oyster responses to extreme low salinity and high temperature combinations, a series of laboratory studies were conducted. Oysters were placed in 18 tanks in a fully crossed temperature (25°C, 32°C) by salinity (1, 5, and 15) study with three replicates, and repeated at least twice for each oyster size class. Regardless of temperature, seed and market oysters held in low salinity tanks (salinity 1) experienced 100% mortality within 7 days. In contrast, at salinity 5, temperature significantly affected mortality; oysters in all size classes experienced greater than 50%mortality at 32°C and less than 40%mortality at 25°C. At the highest salinity tested (15), only market-sized oysters held at 32°C experienced significant mortality (>60%). These studies demonstrate that high water temperatures (>30°C) and

  6. The Effects of Salinity on the Filtration Rates of Juvenile Tropical Oyster Crassostrea iredalei.

    PubMed

    Chang, Geraldine Olive Ju Lien; Inn, Lai Ven; Hwai, Aileen Tan Shau; Yasin, Zulfigar

    2016-11-01

    A small scale laboratory study was conducted to determine the effects of salinity ranging from 15, 20, 25, 30, 35, 40, and 45 ppt on the filtration rates of juvenile oyster Crassostrea iredalei with 25 ppt as the control. Three juvenile oysters (shell weight: 1.04 ± 0.12 g; shell length: 1.9 ± 0.2 cm; shell height: 1.9 ± 0.1 cm) were used to test the filtration rates in each salinity over the course of 8 hours. The hourly filtration rates were determined from the exponential decrease in algal (Chaetoceros calcitrans) concentration as a function of time. The oyster in 35 ppt salinity produced the highest overall filtration rate (FR2) with 134.06 ± 15.66 mL(-1) hr(-1) oyster(-1) and the lowest overall filtration rate (FR2) occurred in oyster exposed to 15 ppt and 45 ppt with 31.30 ± 6.90 mL(-1) hr(-1) oyster(-1) and 32.11 ± 7.68 mL(-1) hr(-1) oyster(-1) respectively throughout the 8 hours. The result from this study can be useful for optimum oyster culturing and the oysters can be employed as a natural biofilter in marine polyculture farming.

  7. Bioaccumulation and metabolomics responses in oysters Crassostrea hongkongensis impacted by different levels of metal pollution.

    PubMed

    Cao, Chen; Wang, Wen-Xiong

    2016-09-01

    Jiulong River Estuary, located in southern China, was heavily contaminated by metal pollution. In this study, the estuarine oysters Crassostrea hongkongensis were transplanted to two sites with similar hydrological conditions but different levels of metal pollution in Jiulong River Estuary over a six-month period. We characterized the time-series change of metal bioaccumulation and final metabolomics responses of oysters. Following transplantation, all metals (Cd, Cu, Cr, Ni, Pb, and Zn) in the oyster digestive glands had elevated concentrations over time. By the end of six-month exposure, Cu, Zn and Cd were the main metals significantly differentiating the two sites. Using (1)H NMR metabolite approach, we further demonstrated the disturbance in osmotic regulation, energy metabolism, and glycerophospholipid metabolism induced by metal contaminations. Six months later, the oysters transplanted in the two sites showed a similar metabolite variation pattern when compared with the initial oysters regardless of different metal levels in the tissues. Interestingly, by comparing the oysters from two sites, the more severely polluted oysters accumulated significantly higher amounts of osmolytes (betaine and homarine) and lower energy storage compounds (glycogen) than the less polluted oysters; these changes could be the potential biomarkers for different levels of metal pollution. Our study demonstrated the complexity of biological effects under field conditions, and NMR metabolomics provides an important approach to detect sensitive variation of oyster inner status.

  8. COMPARISON OF CARBON AND NITROGEN FLUXES IN TIDEFLAT FOOD WEBS DOMINATED BY BURROWING SHRIMP OR BY CULTURED OYSTERS

    EPA Science Inventory

    Two species of indigenous, thalassinid burrowing shrimps are pests to the benthic culture of Pacific oysters (Crassostrea gigas) because deposition of sediment excavated by the shrimps buries or smothers the oysters. Carbaryl pesticide is used to reduce burrowing shrimp densitie...

  9. AN OVACYSTIS-LIKE CONDITION IN THE AMERICAN OYSTER CRASSOSTREA VIRGINICA GMELIN FROM THE NORTHEASTERN GULF OF MEXICO

    EPA Science Inventory

    Histological examination of the eastern oyster, Crassostrea virginica, from a study in Pensacola Bay, Florida, revealed two cases of abnormally large, basophilic ova that resemble ovacystis disease previously reported in oysters from Maine and Long Island. The hypertrophied gamet...

  10. PROGRESSION OF DISEASES CAUSED BY THE OYSTER PARASITES, PERKINSUS MARINUS AND HAPLOSPORIDIUM NELSONI IN CRASSOSTREA VIRGINICA ON CONSTRUCTED INTERTIDAL REEFS

    EPA Science Inventory

    The progression of diseases caused by the oyster parasites, Perkinsus marinus and Haplosporidium nelsoni, were evaluated by periodic sampling (May 1994 - December 1995) of oysters, Crassostrea virginica, on an artificial reef located in the Piankatank River, Virginia. The infecti...

  11. Management of health risks associated with oysters harvested from a norovirus contaminated area, Ireland, February-March 2010.

    PubMed

    Doré, B; Keaveney, S; Flannery, J; Rajko-Nenow, P

    2010-05-13

    Oysters from a harvesting area responsible for outbreaks of gastroenteritis were relaid at a clean seawater site and subsequently depurated in tanks of purified seawater at elevated temperatures. This combined treatment reduced norovirus levels to those detected prior to the outbreak. On the basis of norovirus monitoring the sale of treated oysters was permitted although the harvest area remained closed for direct sale of oysters. No reports of illness have been associated with the consumption of treated oysters.

  12. An outbreak of norovirus linked to oysters in Tasmania.

    PubMed

    Lodo, Kerryn L; Veitch, Mark G K; Green, Michelle L

    2014-03-31

    Norovirus is the most commonly reported virus in shellfish related gastroenteritis outbreaks. In March 2013 an investigation was conducted following the receipt of reports of gastroenteritis after the consumption of oysters at private functions in Tasmania. Cases were ascertained through general practitioners, emergency departments, media releases and self-reporting. Of the 306 cases identified in Tasmania, ten faecal specimens were collected for laboratory testing and eight were positive for norovirus (GII.g). The most common symptoms were vomiting (87%), diarrhoea (85%), myalgia (82%) and fever (56%). The implicated oysters were traced to a single lease from which they were harvested and distributed locally and interstate. Nationally 525 cases were identified from Tasmania (306), Victoria (209), New South Wales (8) and Queensland (2). This report highlights the consequences of norovirus outbreaks in shellfish, even with rapid identification, trace back and removal of the implicated product from the market.

  13. Plesiomonas shigelloides Periprosthetic Knee Infection After Consumption of Raw Oysters.

    PubMed

    Hustedt, Joshua W; Ahmed, Sarim

    Periprosthetic infections are a leading cause of morbidity after total joint arthroplasty. Common pathogens include Staphylococcus aureus, streptococcus, enterococcus, Escherichia coli, and Pseudomonas aeruginosa. However, there are many cases in which rare bacteria are isolated. This case report describes a periprosthetic knee infection caused by Plesiomonas shigelloides. In the United States, P shigelloides and 2 other Vibrionaceae family members, Vibrio vulnificus and Vibrio parahaemolyticus, are most often contracted from eating raw oysters and shellfish. P shigelloides usually causes a self-limiting watery diarrhea, but in immunosuppressed people it can cause septicemia. In this case report, a chemically and biologically immunosuppressed man consumed raw oysters and developed P shigelloides septicemia and acute periprosthetic knee infection that required surgical intervention.

  14. A feeding model of oyster larvae (Crassostrea angulata).

    PubMed

    Qiu, Tianlong; Liu, Ying; Zheng, Jimeng; Zhang, Tao; Qi, Jianfei

    2015-08-01

    There is a need to develop more efficient rearing systems for the aquaculture of economically important bivalves, such as oysters. Here, we constructed a model that describes the feeding behavior of larval Crassostrea angulata oysters and tested it in an experimental setting. Larval ingestion rate is closely correlated with larval length. Based on our model, we showed that larval swimming speed, velum diameter and the filtration coefficient, which also determine the ingestion rate, are also correlated with larval length. Our model integrates morphological, locomotory and feeding behavior parameters to establish a relation between them and so provides a mathematical way to describe variation in the feeding behavior of bivalve larvae. The results of this study could facilitate the precise management of the aquaculture of bivalve larvae, in particular the optimum prey density and feeding rate of these important organisms.

  15. Multibiomarker assessment of three Brazilian estuaries using oysters as bioindicators

    SciTech Connect

    Valdez Domingos, F.X. Azevedo, M.; Silva, M.D.; Randi, M.A.F.; Freire, C.A.; Silva de Assis, H.C.; Oliveira Ribeiro, C.A.

    2007-11-15

    Oysters have been largely employed as bioindicators of environmental quality in biomonitoring studies. Crassostrea rhizophorae was selected to evaluate the health status of three estuarine areas impacted by anthropogenic activities along the Brazilian coast, in three estuarine complexes, ranging in latitude from 7 to 25 deg. S. In each estuary three sites were sampled in Winter and in Summer: a site considered as reference, and two sites next to contamination sources. Condition index was similar at all sites and estuaries, with the highest values found for Itamaraca oysters in Summer. Necrosis, hyperplasia, mucocyte hypertrophy and fusion of ordinary filaments were the main histopathological lesions observed. Muscle cholinesterase activity was overall similar, but with a strong seasonal effect. Inhibition or activation of branchial total ATPase and Na,K-ATPase activities at the contaminated sites was observed. The health status of these estuarine areas is quite similar, and the combined use of biomarkers is recommended.

  16. When r-selection may not predict introduced-species proliferation: predation of a nonnative oyster.

    PubMed

    Bishop, Melanie J; Peterson, Charles H

    2006-04-01

    Predicting outcomes of species introductions may be enhanced by integrating life-history theory with results of contained experiments that compare ecological responses of exotic and analogue native species to dominant features of the recipient environment. An Asian oyster under consideration for introduction to the Chesapeake Bay, USA, the rapidly growing Suminoe oyster (Crassostrea ariakensis), may not be as successful an invader as its r-selected life history suggests if the trade-off for rapid growth and maturation is lower investment in defenses against blue crab (Callinectes sapidus) predation than the native Eastern oyster (Crassostrea virginica). In laboratory trials, blue crabs simultaneously offered equal numbers of Suminoe and Eastern oysters consumed more nonnatives, irrespective of whether the crabs had previous experience with Suminoe oysters as prey. Satiated blue crabs consumed nearly three times as many Suminoe oysters as Eastern oysters of 25-mm shell height, and eight times as many of 35-mm shell height. Despite blue crabs consuming small (30 mm) Suminoe oysters at twice the rate of large (40 mm) Suminoe oysters, when 40-mm Suminoe were paired with 30-mm Eastern oysters, seven times as many of the larger (Suminoe) oysters were consumed. The greater susceptibility of C. ariakensis than C. virginica to blue crab predation appears to be based upon the biomechanics of shell strength rather than active selection of a more attractive food. Much less force was required to crush shells of Suminoe than Eastern oysters of similar shell height. Tissue transplant experiments demonstrated greater predation on oyster tissues in weaker C. ariakensis shells independent of tissue identity, and duration of handling time before rejection of C. virginica exceeded the time to crush C. ariakensis. These results, coupled with the present importance of blue crab predation in limiting recovery of native Eastern oysters, imply a role for blue crabs in inhibiting Suminoe

  17. Factors affecting the uptake and retention of Vibrio vulnificus in oysters.

    PubMed

    Froelich, Brett A; Noble, Rachel T

    2014-12-01

    Vibrio vulnificus, a bacterium ubiquitous in oysters and coastal water, is capable of causing ailments ranging from gastroenteritis to grievous wound infections or septicemia. The uptake of these bacteria into oysters is often examined in vitro by placing oysters in seawater amended with V. vulnificus. Multiple teams have obtained similar results in studies where laboratory-grown bacteria were observed to be rapidly taken up by oysters but quickly eliminated. This technique, along with suggested modifications, is reviewed here. In contrast, the natural microflora within oysters is notoriously difficult to eliminate via depuration. The reason for the transiency of exogenous bacteria is that those bacteria are competitively excluded by the oyster's preexisting microflora. Evidence of this phenomenon is shown using in vitro oyster studies and a multiyear in situ case study. Depuration of the endogenous oyster bacteria occurs naturally and can also be artificially induced, but both of these events require extreme conditions, natural or otherwise, as explained here. Finally, the "viable but nonculturable" (VBNC) state of Vibrio is discussed. This bacterial torpor can easily be confused with a reduction in bacterial abundance, as bacteria in this state fail to grow on culture media. Thus, oysters collected from colder months may appear to be relatively free of Vibrio but in reality harbor VBNC cells that respond to exogenous bacteria and prevent colonization of oyster matrices. Bacterial-uptake experiments combined with studies involving cell-free spent media are detailed that demonstrate this occurrence, which could explain why the microbial community in oysters does not always mirror that of the surrounding water.

  18. Effects of refrigeration and alcohol on the load of Aeromonas hydrophila in oysters.

    PubMed

    Birkenhauer, J M; Oliver, J D

    2002-03-01

    Members of the bacterial genus Aeromonas are widely distributed throughout the environment and are readily cultured from a variety of foods. One member of this genus, Aeromonas hydrophila, has been reputed to be a significant cause of gastrointestinal disease. In this study, we examined the effects of refrigeration and alcohol on the level of A. hydrophila in oysters. Specifically, vodka was examined because it is used by the food service industry in preparation of Oysters Romanoff. One set of oysters was shucked on receipt, whereas others were refrigerated intact for 7 days at 5 degrees C. The oysters were blended and the numbers of A. hydrophila present determined using starch ampicillin agar. Oysters were also shucked and placed on the half shell with 5 ml of vodka for 10 min. The oysters were then washed and presumptive A. hydrophila levels determined in both the washate and homogenate. On the day of purchase, the average number of presumptive A. hydrophila found was 7.6 x 10(4) CFU/g of oyster meat. After 7 days of refrigeration, the average number had increased to 3.2 x 10(5) CFU/g of oyster meat. In the oysters treated with vodka, the average number of A. hydrophila present internally was 9.9 x 10(4) with high numbers (10(3) to 10(4)) isolated from the oyster surface. From these data, it is clear that refrigeration and alcohol treatment are not sufficient to reduce loads of A. hydrophila in or on oysters.

  19. A survey of the Oyster Creek reload licensing model

    SciTech Connect

    Alammar, M.A. )

    1991-01-01

    The Oyster Creek RETRAN licensing model was submitted for approval by the U.S. Nuclear Regulatory Commission in September 1987. This paper discusses the technical issues and concerns that were raised during the review process and how they were resolved. The technical issues are grouped into three major categories: the adequacy of the model benchmark against plant data; uncertainty analysis and model convergence with respect to various critical parameters (code correlations, nodalization, time step, etc.); and model application and usage.

  20. Oyster Reef Communities in the Chesapeake Bay. Virginia Institute of Marine Science Educational Series. [CD-ROM].

    ERIC Educational Resources Information Center

    Harding, Juliana M.; Mann, Roger; Clark, Vicki P.

    This CD-ROM, Oyster Reef Communities in the Chesapeake Bay, describes oyster reefs, reef communities, and their roles in the Chesapeake Bay ecosystem. Detailed descriptions of scientific research methods and techniques used to monitor and describe oyster reef communities as well as applications of the resulting data are provided. The CD-ROM was…

  1. 76 FR 59423 - Drakes Bay Oyster Company Special-Use Permit, Draft Environmental Impact Statement, Point Reyes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-26

    ... National Park Service Drakes Bay Oyster Company Special-Use Permit, Draft Environmental Impact Statement... statement to consider the Drakes Bay Oyster Company Special-use permit in Drakes Estero, Point Reyes... National Seashore Web site, at http://parkplanning.nps.gov/pore (click on the Drakes Bay Oyster...

  2. 75 FR 65373 - Drakes Bay Oyster Company Special Use Permit/Environmental Impact Statement, Point Reyes National...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-22

    ... National Park Service Drakes Bay Oyster Company Special Use Permit/Environmental Impact Statement, Point... Intent to prepare an Environmental Impact Statement for the Drakes Bay Oyster Company Special Use Permit... Statement (EIS) for the Drakes Bay Oyster Company Special Use Permit, Point Reyes National...

  3. Are oysters being bored to death? Influence of Cliona celata on Crassostrea virginica condition, growth and survival.

    PubMed

    Carroll, John M; O'Shaughnessy, Kathryn A; Diedrich, Grant A; Finelli, Christopher M

    2015-11-17

    The boring sponge Cliona celata is a nuisance species that can have deleterious effects on eastern oyster Crassostrea virginica growth, condition, and survival. Surprisingly, however, these effects have not been well documented and when examined, results have been equi-vocal. In this study, we provide a direct comparison of growth, condition, and survival of sponge-colonized and uncolonized oysters in southeast North Carolina in 2 separate experiments. In the first experiment, sponge-colonized oysters exhibited significantly slower growth rates, reduced condition, and lower survival relative to uncolonized oysters, although results may have been confounded by oyster source. In the second experiment, using smaller oysters from the same source population, growth rate was again significantly reduced in colonized oysters relative to uncolonized oysters, however neither condition nor survival differed. In field surveys of the same population, colonized individuals across a range of sizes demonstrated significantly reduced condition. Further, condition index was negatively correlated with sponge biomass, which was positively correlated with oyster size, suggesting that the impact of the sponge changes with ontogeny. By investigating clearance rates, tissue isotopic and nutrient content, as well as caloric value, this study provides further evidence that sponge presence causes the oysters to divert energy into costly shell maintenance and repair at the expense of shell and somatic growth. Thus, although variable, our results demonstrate negative impacts of sponge infestation on oyster demographics, particularly as oysters grow larger.

  4. 40 CFR 408.250 - Applicability; description of the Pacific Coast hand-shucked oyster processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Pacific Coast hand-shucked oyster processing subcategory. 408.250 Section 408.250 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Pacific Coast Hand-Shucked Oyster Processing Subcategory § 408.250 Applicability; description of the Pacific Coast hand-shucked oyster processing subcategory....

  5. 40 CFR 408.260 - Applicability; description of the Atlantic and Gulf Coast hand-shucked oyster processing...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Atlantic and Gulf Coast hand-shucked oyster processing subcategory. 408.260 Section 408.260 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Atlantic and Gulf Coast Hand-Shucked Oyster Processing Subcategory § 408.260 Applicability; description of the Atlantic and Gulf Coast hand-shucked oyster...

  6. 40 CFR 408.260 - Applicability; description of the Atlantic and Gulf Coast hand-shucked oyster processing...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Atlantic and Gulf Coast hand-shucked oyster processing subcategory. 408.260 Section 408.260 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Atlantic and Gulf Coast Hand-Shucked Oyster Processing Subcategory § 408.260 Applicability; description of the Atlantic and Gulf Coast hand-shucked oyster...

  7. 40 CFR 408.250 - Applicability; description of the Pacific Coast hand-shucked oyster processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Pacific Coast hand-shucked oyster processing subcategory. 408.250 Section 408.250 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Pacific Coast Hand-Shucked Oyster Processing Subcategory § 408.250 Applicability; description of the Pacific Coast hand-shucked oyster processing subcategory....

  8. 40 CFR 408.250 - Applicability; description of the Pacific Coast hand-shucked oyster processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Pacific Coast hand-shucked oyster processing subcategory. 408.250 Section 408.250 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Pacific Coast Hand-Shucked Oyster Processing Subcategory § 408.250 Applicability; description of the Pacific Coast hand-shucked oyster processing subcategory....

  9. 40 CFR 408.260 - Applicability; description of the Atlantic and Gulf Coast hand-shucked oyster processing...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Atlantic and Gulf Coast hand-shucked oyster processing subcategory. 408.260 Section 408.260 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Atlantic and Gulf Coast Hand-Shucked Oyster Processing Subcategory § 408.260 Applicability; description of the Atlantic and Gulf Coast hand-shucked oyster...

  10. 40 CFR 408.250 - Applicability; description of the Pacific Coast hand-shucked oyster processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Pacific Coast hand-shucked oyster processing subcategory. 408.250 Section 408.250 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Pacific Coast Hand-Shucked Oyster Processing Subcategory § 408.250 Applicability; description of the Pacific Coast hand-shucked oyster processing subcategory....

  11. 40 CFR 408.260 - Applicability; description of the Atlantic and Gulf Coast hand-shucked oyster processing...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Atlantic and Gulf Coast hand-shucked oyster processing subcategory. 408.260 Section 408.260 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Atlantic and Gulf Coast Hand-Shucked Oyster Processing Subcategory § 408.260 Applicability; description of the Atlantic and Gulf Coast hand-shucked oyster...

  12. 40 CFR 408.250 - Applicability; description of the Pacific Coast hand-shucked oyster processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Pacific Coast hand-shucked oyster processing subcategory. 408.250 Section 408.250 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Pacific Coast Hand-Shucked Oyster Processing Subcategory § 408.250 Applicability; description of the Pacific Coast hand-shucked oyster processing subcategory....

  13. 40 CFR 408.260 - Applicability; description of the Atlantic and Gulf Coast hand-shucked oyster processing...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Atlantic and Gulf Coast hand-shucked oyster processing subcategory. 408.260 Section 408.260 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Atlantic and Gulf Coast Hand-Shucked Oyster Processing Subcategory § 408.260 Applicability; description of the Atlantic and Gulf Coast hand-shucked oyster...

  14. Habitat Suitability Index Models: Gulf of Mexico American Oyster

    USGS Publications Warehouse

    Cake, Edwin W.

    1983-01-01

    The American or eastern oyster (Crassostrea virrinica [Gmelin]), a bivalve in the family Ostreidae, is an important commercia and recreational species along the Atlantic and Gulf of Mexico coasts of North America and other areas (U.S. Pacific coast and Hawaii) where it has been introduced (Galtsoff 1964). It evolved over the last 25 million years (Miocene and Pliocene epochs) from an ancestral, Atlantic-Pacific species that also gave rise to the Central American oyster of the Pacific coast, Crassostrea corteziensis (Hertlein) (Stenzel 1971). It evolved to fill a eurytopic niche in coastal estuaries where it forms massive reefs in nearshore bays, sounds, lagoons, and river mouths. Its existence depends on suitable substratum (cultch and firm bottom sediments) and acceptable sal-inity conditions. The location and distribution of oyster reefs in a salt marsh-estuari ne ecosystem are not acci denta 1; rather, they result from the interacti on of many bi 01 ogi ca 1, chemica1, geo1ogi ca1, and phys i ca 1 processes (Butler 1954a; Marshall 1954; Bahr and Lanier 1981).

  15. Flow and Turbulence Over an Oyster Reef Bank

    NASA Astrophysics Data System (ADS)

    Styles, R.

    2006-12-01

    In December of 2005, measurements of flow and turbulence were collected on opposite sides of a subtidal channel in the North Inlet/Winyah Bay National Estuary Research Reserve. One bank included an extensive cover of oyster reefs and the other was a mixture of fine sands and mud. The purpose was to examine the differences in flow and turbulence structure in a similar flow regime but with greatly varying roughness environments. Peak along channel velocities were higher on the mud bank side of the channel. Turbulent kinetic energy and Reynolds stresses components were generally greater over the oyster reef, but maximum values were sometimes highest over the sand/mud bank. Turbulence quantities were also anisotropic at both sites. During early flood, the lateral circulation was consistent with flow around a bend, with weak flow directed towards the inside of the bank at the bottom. The lateral circulation reversed direction during mid flood even though the current was still in the same direction. Implications describing the interaction between bed morphology and oyster reefs will be discussed.

  16. Detection of Toxoplasma gondii DNA in Brazilian oysters (Crassostrea rhizophorae).

    PubMed

    Ribeiro, L A; Santos, L K N S S; Brito, P A; Maciel, B M; Da Silva, A V; Albuquerque, G R

    2015-05-04

    The aim of this study was to detect evidence of Toxoplasma gondii using polymerase chain reaction (PCR)-based techniques in oysters (Crassostrea rhizophorae) obtained from the southern coastal region of Bahia, Brazil. A total of 624 oysters were collected, and the gills and digestive glands were dissected. Each tissue sample was separated into pools containing tissues (of the same type) from three animals, leading to a total of 416 experimental samples for analysis (208 samples each from the gills and digestive glands). Molecular analysis using PCR-based detection of the T. gondii AF 146527 repetitive fragment yielded negative results for all samples. However, when nested-PCR was used for detection of the T. gondii SAG-1 gene, 17 samples were positive, with the gills being the tissue with maximal detection of the parasite. These positive results were confirmed by sample sequencing. It is therefore suggested that C. rhizophorae oysters are capable of filtering and retaining T. gondii oocysts in their tissue. This represents a risk to public health because they are traditionally ingested in natura.

  17. Impact of atrazine on aneuploidy in pacific oysters, Crassostrea gigas.

    PubMed

    Bouilly, Karine; Leitão, Alexandra; McCombie, Helen; Lapègue, Sylvie

    2003-01-01

    Aneuploidy has previously been described and studied in the Pacific oyster, Crassostrea gigas, and has been shown to be negatively correlated with growth. The present study investigated the effect of atrazine on the level of aneuploidy in this species. Crassostrea gigas adults and juveniles were subjected to different concentrations of atrazine representing a peak value found in a polluted environment (46.5 nM) and a value 10 times higher (465 nM). Although atrazine did not show any effect on the oyster mortality, significant differences in aneuploidy level were observed between the different treatments (9% for the control, 16% for 46.5 nM and 20% for 465 nM atrazine). Moreover, the same levels of aneuploidy were observed at adult and juvenile stages. This is the first reported evidence for an environmental effect on aneuploidy in C. gigas. These results will be useful for the oyster aquaculture industry and management of resources. The lowest atrazine level in the current study represents realistic potential exposure, and the results suggest that studies should be made on other aquatic species at risk of exposure to atrazine in the wild. This widely used compound may be an important factor causing damage to genetic material.

  18. Identification of the Molecular Clockwork of the Oyster Crassostrea gigas

    PubMed Central

    Perrigault, Mickael; Tran, Damien

    2017-01-01

    Molecular clock system constitutes the origin of biological rhythms that allow organisms to anticipate cyclic environmental changes and adapt their behavior and physiology. Components of the molecular clock are largely conserved across a broad range of species but appreciable diversity in clock structure and function is also present especially in invertebrates. The present work aimed at identify and characterize molecular clockwork components in relationship with the monitoring of valve activity behavior in the oyster Crassostrea gigas. Results provided the characterization of most of canonical clock gene including clock, bmal/cycle, period, timeless, vertebrate-type cry, rev-erb, ror as well as other members of the cryptochrome/photolyase family (plant-like cry, 6–4 photolyase). Analyses of transcriptional variations of clock candidates in oysters exposed to light / dark regime and to constant darkness led to the generation of a putative and original clockwork model in C. gigas, intermediate of described systems in vertebrates and insects. This study is the first characterization of a mollusk clockwork. It constitutes essential bases to understand interactions of the different components of the molecular clock in C. gigas as well as the global mechanisms associated to the generation and the synchronization of biological rhythms in oysters. PMID:28072861

  19. Experimental ostreid herpesvirus 1 infection of the Pacific oyster Crassostrea gigas: kinetics of virus DNA detection by q-PCR in seawater and in oyster samples.

    PubMed

    Schikorski, D; Faury, N; Pepin, J F; Saulnier, D; Tourbiez, D; Renault, T

    2011-01-01

    Herpes- and herpes-like viruses are known to infect a wide range of bivalve mollusc species throughout the world. Abnormal summer mortalities associated to the detection of ostreid herpesvirus 1 (OsHV-1) have been currently reported in France among larvae and spat of the Pacific cupped oyster Crassostrea gigas. In the present work, we have developed an experimental protocol of horizontal transmission based on the cohabitation between healthy and experimentally infected oysters. Through a cohabitation trial, the kinetics of OsHV-1 detection in different oyster organs and seawater samples were investigated and characterized for the first time using real time quantitative PCR.

  20. Reconstructing pre-colonial oyster demographics in the Chesapeake Bay, USA

    NASA Astrophysics Data System (ADS)

    Mann, Roger; Harding, Juliana M.; Southworth, Melissa J.

    2009-11-01

    Recent estimates of growth and mortality rates in extant Chesapeake Bay, USA oyster ( Crassostrea virginica) populations are used to quantify changes in both population abundance (dN/dT) and shell accretion (dS/dT) associated with modern population demographics. The demographics of oyster populations that would be required to maintain reef accretion rates commensurate with sea level rise over geological time frames are examined using estimates of oyster longevity in pre-colonial (pre -1600) times combined with parallel estimates of pre-disease endemic mortality. The analysis demonstrates that modern populations, with their disease related, age-truncated demographics, are generally not capable of maintaining and building biogenic reefs through accretion. Estimates of filtration rates associated with Chesapeake Bay oyster populations prior to 1600 considerably underestimate actual benthic-pelagic coupling during that period. Pristine oyster populations would have supported water column turnover rates on the order of minutes to hours. Thus, the spatial footprint of oyster reefs was limited by available productivity in the estuary. Accretion rate calculations for pristine (pre-1600) oyster reefs describe the intimate relationship between benthic-pelagic coupling and the presence or absence of oyster reefs and the associated communities.

  1. Differential recruitment of introduced Pacific oysters and native mussels at the North Sea coast: coexistence possible?

    NASA Astrophysics Data System (ADS)

    Diederich, Susanne

    2005-04-01

    Pacific oysters ( Crassostrea gigas Thunberg 1793) have been introduced into the Wadden Sea (North Sea), where they settle on native mussel beds ( Mytilus edulis L.), which represent the only extensive insular hard substrata in this soft-sediment environment. As abundances of C. gigas rose, some mussel beds became increasingly overgrown with oysters, whereas others did not. Field experiments revealed that recruitment of C. gigas was higher in the lower intertidal than in the upper subtidal zone, that it was higher on conspecifics than on mussels, and that it was not affected by barnacle epigrowth except when settling on mussels. Mussel recruitment is known from inter- and subtidal zones. It occurred equally on oyster and mussel shells but showed a clear preference for barnacle epigrowth over clean shells. Assuming that settlement and recruitment are key processes for species abundances on the North Sea coast, it is predicted that the positive feedback in oyster settlement will lead to rapid reef formation of this invader at the expense of mussel beds. Mussels, however, may escape competitive exclusion by settling between or on the larger oysters especially when barnacles are abundant. Experimental patches with mussels were more often covered by fucoid algae ( Fucus vesiculosus forma mytili Nienburg) than patches with oysters, and oyster recruitment was poor underneath such algal canopies. Thus, fucoids may provide the native mussels with a refuge from the invading oysters and the two bivalves may coexist, provided food is not limiting.

  2. Growth and yield performance of Pleurotus ostreatus (Jacq. Fr.) Kumm (oyster mushroom) on different substrates.

    PubMed

    Girmay, Zenebe; Gorems, Weldesemayat; Birhanu, Getachew; Zewdie, Solomon

    2016-12-01

    Mushroom cultivation is reported as an economically viable bio-technology process for conversion of various lignocellulosic wastes. Given the lack of technology know-how on the cultivation of mushroom, this study was conducted in Wondo Genet College of Forestry and Natural Resource, with the aim to assess the suitability of selected substrates (agricultural and/or forest wastes) for oyster mushroom cultivation. Accordingly, four substrates (cotton seed, paper waste, wheat straw, and sawdust) were tested for their efficacy in oyster mushroom production. Pure culture of oyster mushroom was obtained from Mycology laboratory, Department of Plant Biology and Biodiversity Management, Addis Ababa University. The pure culture was inoculated on potato dextrose agar for spawn preparation. Then, the spawn containing sorghum was inoculated with the fungal culture for the formation of fruiting bodies on the agricultural wastes. The oyster mushroom cultivation was undertaken under aseptic conditions, and the growth and development of mushroom were monitored daily. Results of the study revealed that oyster mushroom can grow on cotton seed, paper waste, sawdust and wheat straw, with varying growth performances. The highest biological and economic yield, as well as the highest percentage of biological efficiency of oyster mushroom was obtained from cotton seed, while the least was from sawdust. The study recommends cotton seed, followed by paper waste as suitable substrates for the cultivation of oyster mushroom. It also suggests that there is a need for further investigation on various aspects of oyster mushroom cultivation in Ethiopia to promote the industry.

  3. ANTIOXIDANT ENZYMES, POTENTIAL VIRULENT FACTORS, IN DIFFERENT STRAINS OF THE OYSTER PROTOZOAN PARASITE, PERKINSUS MARINUS

    EPA Science Inventory

    The oyster protozoan parasite, Perkinsus marinus, is one of the two important parasites causing severe mortality in the eastern oysters (Crassostrea virginica) on the US east coast. Our recent study suggests that P. marinus cells and its extracellular products (ECP) could scaveng...

  4. High pressure processing with hot sauce flavoring enhances sensory quality for raw oysters (Crassostrea virginica)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated the feasibility of flavoring raw oysters by placing them under pressure in the presence of selected flavorings. Hand-shucked raw oysters were processed at high pressure (600 MPa), in the presence or absence of (Sriracha®) flavoring, and evaluated by a trained sensory panel 3 an...

  5. Desirability of oysters treated by high pressure processing at different temperatures and elevated pressures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organoleptic changes in sterile triploid oysters (Crassostrea virginica) induced by high pressure processing (HPP) were investigated using a volunteer panel. Using a 1-7 hedonic scale, where seven is “like very much”, and one is “dislike very much”, oysters were evaluated organoleptically for flavo...

  6. Temperature-dependent persistence of human norovirus within oysters (Crassotrea virginica)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study characterizes the persistence of human norovirus in Eastern oysters (Crassostrea virginica) held at different seawater temperatures. Oysters were contaminated with human norovirus GI.1 (Norwalk strain 8fIIa) by exposing them to virus contaminated water at 15 degrees C, and subsequently ho...

  7. Thermal inactivation of enteric viruses and bioaccumulation of enteric foodborne viruses in live oysters (Crassostrea virginica)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Human enteric viruses are one of the main causative agents of shellfish associated outbreaks. In this study, the kinetics of viral bioaccumulation in live oysters and the heat stability of the most predominant enteric viruses were determined in both tissue culture and in oyster tissues. A human nor...

  8. Heavy metals in the eastern oyster, Crassostrea virginica, of the Mississippi Sound

    SciTech Connect

    Lytle, T.F.; Lytle, J.S. )

    1990-01-01

    Levels of metals in oysters in the Sound are of profound interest not only because they document those geographic areas where metal pollution levels may be problematic but because they may disclose possible problems to consumers of oysters. At the present time objective federal standards for heavy metals in oysters and other seafood are restricted to mercury. The closure of Mississippi oyster reefs has been predicated upon bacteriological standards with little if any attention paid to heavy metals. A study of fourteen metals in oysters of the Sound was began in 1988 with objectives differing from that of the Status and Trends Program (STP) in three ways. STP levels are reported on dry weight basis of composites from three sites. In the present study, oysters were analyzed and reported on wet weight basis. Additionally analyses were made of individual specimens to indicate expected specimen to specimen variations and were conducted on oysters from the three STP and two other important oyster reef sites. In the future three or more additional sites will be added to this continuing survey effort. Metals chosen for this study were lead (Pb), cadmium (Cd), iron (Fe), copper (Cu), cobalt (Co), manganese (Mn), zinc (Zn), silver (Ag), nickel (Ni), mercury (Hg), aluminum (Al), chromium (Cr), molybdenum (Mo), and vanadium (V).

  9. High concentrations of trace metals in oysters from the Patuxent River, Maryland

    SciTech Connect

    Riedel, G.; Sanders, J.; Abbe, G.

    1995-12-31

    Oyster (Crassostrea virginica) populations from the Patuxent River have been analyzed for trace metals by a number of organizations over at least the past 19 years. During that period, high concentrations of Cu (200--500 {micro}g/g dry weight), Cd (3--7 {micro}g/g) and Ag (2--8 /{micro}g/g) have been found in oysters from the oyster bars furthest up river. In particular, Cd values in oysters from this region have had concentrations approaching or exceeding current FDA warning levels throughout the period. In previous studies it was suggested that a coal-burning power plant located in that region, Chalk Point Steam Electric Station, was responsible for the copper enrichment due to the corrosion of Cu/Ni alloy condenser tubes. However, a monthly survey of trace elements in the nearby oyster populations from 1986 to the present showed only a small decline in copper concentrations after the plant switched from Cu/Ni to Ti alloy condenser tubes in 1987. Other potential sources for trace metals in the region include municipal and industrial discharges, atmospheric deposition, and biocides (anti-fouling paint in particular). The very rapid rise in trace element concentrations in oysters with position up river, and the lack of such a response by another local bivalve, the hooked mussel (Ischadium recurvum), suggests that a physiological effect of low salinity stress on oysters may be in part responsible for the high concentrations of trace metals in oysters in this region.

  10. Energy and antioxidant responses of pacific oyster exposed to trace levels of pesticides.

    PubMed

    Epelboin, Yanouk; Quéré, Claudie; Pernet, Fabrice; Pichereau, Vianney; Corporeau, Charlotte

    2015-09-21

    Here, we assess the physiological effects induced by environmental concentrations of pesticides in Pacific oyster Crassostrea gigas. Oysters were exposed for 14 d to trace levels of metconazole (0.2 and 2 μg/L), isoproturon (0.1 and 1 μg/L), or both in a mixture (0.2 and 0.1 μg/L, respectively). Exposure to trace levels of pesticides had no effect on the filtration rate, growth, and energy reserves of oysters. However, oysters exposed to metconazole and isoproturon showed an overactivation of the sensing-kinase AMP-activated protein kinase α (AMPKα), a key enzyme involved in energy metabolism and more particularly glycolysis. In the meantime, these exposed oysters showed a decrease in hexokinase and pyruvate kinase activities, whereas 2-DE proteomic revealed that fructose-1,6-bisphosphatase (F-1,6-BP), a key enzyme of gluconeogenesis, was up-regulated. Activities of antioxidant enzymes were higher in oysters exposed to the highest pesticide concentrations. Both pesticides enhanced the superoxide dismutase activity of oysters. Isoproturon enhanced catalase activity, and metconazole enhanced peroxiredoxin activity. Overall, our results show that environmental concentrations of metconazole or isoproturon induced subtle changes in the energy and antioxidant metabolisms of oysters.

  11. Magnification of tributyl tin toxicity to oyster larvae by bioconcentration in biofilms of Shewanella colwelliana.

    PubMed Central

    Labare, M L; Coon, S L; Matthias, C; Weiner, R M

    1997-01-01

    The toxic effects of dissolved versus bioconcentrated tributyl tin (TBT) on oyster larvae were compared. Water column TBT levels, which had no effect in solution, inhibited natural attachment and metamorphosis of oyster larvae on bottom surfaces due to bioconcentration by biofilms. This mechanism should be considered when evaluating heavy metal toxicity in the environment. PMID:9327578

  12. Characterization studies on the cadmium-binding proteins from two species of New Zealand oysters.

    PubMed Central

    Nordberg, M; Nuottaniemi, I; Cherian, M G; Nordberg, G F; Kjellström, T; Garvey, J S

    1986-01-01

    Two different types of New Zealand oysters--Ostrea lutaria (OL) and Crassostrea glomerata (CG)--contained different concentrations of zinc, copper, and cadmium. OL oysters had 5.3 micrograms Cd/g, 3.4 micrograms Cu/g, 100 micrograms Zn/g; CG oysters had 1.4 micrograms Cd/g and 936 micrograms Zn/g. Both kinds of oysters were shown by gel filtration (G-75) to contain cadmium and zinc in fractions corresponding to a high molecular weight protein (corresponding to the size of albumin or larger) which was heat labile. OL oysters contained cadmium in fractions corresponding to a molecular weight of approximately 6500. The cadmium-binding protein in these fractions was heat-stable. This protein contained no detectable amounts of zinc and was not present in the CG oysters. Further purification by gel filtration (G-50) was performed to obtain a purer protein fraction. Isoelectric focusing of the protein obtained by G-50 filtration showed one main fraction of protein with a pI approximately 5.9 at approximately 13 degrees C. CG oysters contained cadmium and zinc in a polypeptide with low molecular weight (MW 1000). The cadmium-binding oyster proteins are minimally reactive in a competitive binding radioimmunoassay in comparison to the reactivity of a typical vertebrate metallothionein; the proteins may be metallothioneins, but, if so, they do not exhibit the principal determinants characteristic of vertebrate metallothioneins. PMID:3709467

  13. Bacterial loads and microbial composition in high pressure treated oysters during storage.

    PubMed

    Prapaiwong, Naparat; Wallace, Richard K; Arias, Covadonga R

    2009-05-31

    Analysis of bacterial communities present in high-pressure (HP)-treated, quick-frozen (QF), and raw oysters was carried out during three different seasons. Bacterial numbers and species diversity in each sample were determined at 0, 7, 14, and 21 days of storage. Results showed that numbers of total aerobic bacterial counts (TABC) in treated oysters were significantly lower than in untreated oysters at day 0 by 10 to 10(5) colony forming units per gram of oyster meat (CFU/g) in all samplings. However, an increase in TABC in HP-treated oysters was observed at days 7, 14, and 21 indicating that some bacteria survived the treatment and were able to proliferate during refrigeration conditions. Surprisingly, TABC in HP-treated oysters reached 10(8) CFU/g at 14 days of storage in all samplings (higher than TABC from raw oysters in two of the samplings performed). Analysis of the bacterial flora by 16S rDNA sequencing, revealed six different classes within the bacterial communities. The majority were Gram-negative bacteria, with the Gammaproteobacteria class representing between 56% and 92%. The most common bacterial genera found in this study were Shewanella, Vibrio and Psychrobacter. Four species of human pathogenic bacteria were also identified: V. vulnificus, V. parahaemolyticus, V. alginolyticus, and A. hydrophila although V. vulnificus was detected only in raw oysters.

  14. Acanthoparyphium sp. and other metazoan symbionts of the American oyster, Crassostrea virginica, from South Texas.

    PubMed

    Fredensborg, B L; Ramirez, J J; Partida, L

    2013-12-01

    In this study, we investigated oysters, Crassostrea virginica , from Laguna Madre in South Texas, where a 45-yr old study recorded metacercarial infections of the echinostomatid trematode, Acanthoparyphium spinulosum , an Asian relative of which, Acanthoparyphium tyosenense, has been associated with human infections via the ingestion of raw mollusks. In an effort to examine the base-line infection parameters of Acanthoparyphium sp. in oysters, we examined the effect of distance from the shoreline, which is the habitat of the first intermediate host snail, Cerithidea pliculosa, as well as temporal changes in oyster infection levels, by conducting quarterly collections of oysters during a year. We found that almost all oysters (prevalence = 97.8-100%) were infected regardless of distance to the shoreline and season. However, the abundance of metacercariae was significantly higher close to the shoreline, while no significant temporal changes could be detected. In addition to the echinostomatid, we found a high abundance of the metacestode Tylocephalum sp. and the presence of 4 other metazoan parasites. None of the infections seemed to incur significant tissue damage to the oysters. Our study shows that at least locally, recreational harvesters of oysters may be exposed to Acanthoparyphium sp. Future studies should examine oysters from snail host habitats in the Gulf of Mexico, and the potential zoonotic risk of Acanthoparyphium sp. should be evaluated using experimental infections of animal models.

  15. RESPONSES OF OYSTERS AND THEIR HEMOCYTES TO CLINICAL AND ENVIRONMENTAL ISOLATES OF VIBRIO PARAHAEMOLYTICUS

    EPA Science Inventory

    Interactions of Vibrio parahaemolyticus with oysters and oyster hemocytes were studied using three environmental isolates (1094, 1163 and ATCC 17802) and three clinical isolates (2030, 2062, 2107). Clinical isolates were from patients who became ill during the June 1998 food pois...

  16. A study of diagnostic methods for Marteilioides chungmuensis infections in the Pacific oyster Crassostrea gigas.

    PubMed

    Choi, Hee Jung; Hwang, Jee Youn; Choi, Dong Lim; Huh, Min Do; Park, Myoung Ae

    2012-09-15

    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 reaction [PCR] amplification and in situ hybridization [ISH]) to identify M. chungmuensis-infected oysters. The efficacy of PCR and ISH to identify M. chungmuensis-infected oysters was compared to that of routine histology in 100 oysters. Thirty infections were identified using PCR and 16 using histology, whereas 31 infections were identified using ISH. The ISH and PCR assays were more sensitive compared to using histology with standard epidemiological methods. We strongly recommend that early parasitic invasion should be monitored with PCR/ISH methodologies as a basis for developing effective diagnostic techniques to identify M. chungmuensis-infected oysters.

  17. FACTORS INFLUENCING IN VITRO KILLING OF BACTERIA BY HEMOCYTES OF THE EASTERN OYSTER (CRASSOSTREA VIRGINICA)

    EPA Science Inventory

    A tetrazolium dye reduction assay was used to study factors governing killing of bacteria by oyster hemocytes. In vitro tests were performed on bacterial strains by using hemocytes from oysters collected from the same location in winter and summer. Vibrio parahaemolyticus strains...

  18. ANTIMICROBIAL ACTIVITY OF COPPER AND ZINC ACCUMULATED BY EASTERN OYSTER AMEBOCYTES

    EPA Science Inventory

    Fisher, William S. Submitted. Antimicrobial Activity of Copper and Zinc Accumulated by Eastern Oyster Amebocytes. J. Shellfish Res. 54 p. (ERL,GB 1196).

    The distribution of eastern oysters Crassostrea virginica near terrestrial watersheds has led to a general impression t...

  19. The Potential Use of Electricity to Control Burrowing Shrimp in Oyster Aquaculture Beds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thalassinid shrimp cause significant problems for oyster aquaculture in the Pacific Northwest (USA) where oysters succumb to the physical disruption of the sediment by the burrowing activity of these animals. While electrofishing is a commonly used technique to capture fish and some invertebrates i...

  20. Digital PCR for Quantifying Norovirus in Oysters Implicated in Outbreaks, France

    PubMed Central

    Polo, David; Schaeffer, Julien; Fournet, Nelly; Le Saux, Jean-Claude; Parnaudeau, Sylvain; McLeod, Catherine

    2016-01-01

    Using samples from oysters clearly implicated in human disease, we quantified norovirus levels by using digital PCR. Concentrations varied from 43 to 1,170 RNA copies/oyster. The analysis of frozen samples from the production area showed the presence of norovirus 2 weeks before consumption. PMID:27869597

  1. Weight and salinity effects on zinc uptake and accumulation for the American oyster (Crassostrea virginica Gmelin).

    PubMed

    Mo, C; Neilson, B

    1993-01-01

    The power relationships of short-term net uptake and of in-situ body burden with body weight were examined. The accumulation of soft tissue zinc in the American oyster (Crassostrea virginica) was related to time integration of uptake. Short term uptake of (65)Zn was measured in the laboratory. It was (i) a function of the (dry soft-tissue) weight of the oyster, (ii) inversely related to the salinity of the ambient water, and (iii) increased linearly with ambient concentrations. When in-situ soft-tissue zinc body burdens of oysters from the James River and the Rappahannock River were fit to power functions of body weights (y = aWb), the values of b for all sites were larger by 1 than the powers for (65)Zn uptake when b was adjusted for the oyster-bed salinities. The soft-tissue zinc concentration (y/W) of an oyster increased continuously, but the rate of the increase was reduced as the oyster grows larger. Both short-term uptake and in-situ body burden varied with salinity. The soft-tissue zinc concentrations of hooked mussels (Ischadium recurvum) from the Rappahannock River oyster beds, contrary to the oysters, appeared to be in equilibrium with ambient concentrations.

  2. Kl-impregnated Oyster Shells as a Solid Catalyst for Soybean Oil Transesterificaton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research on inexpensive and green catalysts is needed for economical production of biodiesel. The goal of the research was to test KI-impregnated oyster shell as a solid catalyst for transesterification of soybean oil. Specific objectives were to characterize KI-impregnated oyster shell, determine t...

  3. On the Half Shell: An Introduction to Oysters and Their Unique Structures and Function

    ERIC Educational Resources Information Center

    Frederick, J. Adam; Haines, Sarah; Romano, Christina; Takacs, Jacqueline

    2017-01-01

    The eastern oyster, "Crassostrea virginica," is an ecologically and economically important species in Chesapeake Bay. Oysters are ecologically unique in the Chesapeake Bay because they build a structure known as a bar or reef by attaching to one another over a 45 long period of time. They have been coined the "Ecological Engineers…

  4. Evidence for the involvement of pathogenic bacteria in summer mortalities of the Pacific oyster Crassostrea gigas.

    PubMed

    Garnier, M; Labreuche, Y; Garcia, C; Robert, M; Nicolas, J L

    2007-02-01

    A study was conducted to investigate the involvement of bacteria in oyster mortalities during summer. Moribund and apparently healthy oysters were sampled during mortality events along the French coast and in rearing facilities, usually when temperature reached 19 degrees C or higher, and oysters were in the gonadal maturation phase. Hemolymph samples were aseptically withdrawn and submitted to bacteriological analysis. In healthy oysters, bacteria colonized hemolymph at low concentrations depending on the location. In most moribund oysters, bacteria were present in hemolymph and other tissues. These bacterial populations were more often diverse in oysters originating from the open sea than from facilities where animals were generally infected by a single type of bacterium. Only the dominant colonies were identified by phenotypic and genotypic characters (RFLP of GyrB gene and partial sequence of 16S rRNA gene). They belonged to a limited number of species including Vibrio aestuarianus, members of the V. splendidus group, V. natriegens, V. parahaemolyticus, and Pseudoalteromonas sp. The most frequently encountered species was V. aestuarianus (56% of isolates), which was composed of several strains closely related by their 16S rRNA gene but diverse by their phenotypic characters. They appeared intimately linked to oysters. The species within the V. splendidus group were less prevalent (25% of isolates) and more taxonomically dispersed. A majority of the dominant strains of V. aestuarianus and V. splendidus group injected to oysters induced mortality, whereas others belonging to the same species, particularly those found in mixture, appeared innocuous.

  5. Comparison of different methods for isolation of bacterial DNA from retail oyster tissues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oysters are filter-feeders that bio-accumulate bacteria in water while feeding. To evaluate the bacterial genomic DNA extracted from retail oyster tissues, including the gills and digestive glands, four isolation methods were used. Genomic DNA extraction was performed using the Allmag™ Blood Genomic...

  6. A new identification method for five species of oysters in genus Crassostrea from China based on high-resolution melting analysis

    NASA Astrophysics Data System (ADS)

    Wang, Jiafeng; Xu, Fei; Li, Li; Zhang, Guofan

    2014-03-01

    The high phenotypic plasticity in the shell of oysters presents a challenge during taxonomic and phylogenetic studies of these economically important bivalves. However, because DNA can exhibit marked differences among morphologically similar species, DNA barcoding offers a potential means for oyster identification. We analyzed the complete sequences of the cytochrome oxidase subunit I (COI) of five common Crassostrea species in China (including Hong Kong oyster C. hongkongensis, Jinjiang oyster C. ariakensis, Portuguese oyster C. angulata, Kumamoto oyster C. sikamea, and Pacific oyster C. gigas) and screened for distinct fragments. Using these distinct fragments on a high-resolution melting analysis platform, we developed an identification method that does not rely on species-specific PCR or fragment length polymorphism and is efficient, reliable, and easy to visualize. Using a single pair of primers (Oyster-COI-1), we were able to successfully distinguish among the five oyster species. This new method provides a simple and powerful tool for the identification of oyster species.

  7. Surveying a fossil oyster reef using terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Haring, A.; Exner, U.; Harzhauser, M.

    2009-04-01

    The Korneuburg Basin, situated north-west of Vienna, is well known to contain a rich variety of fossils from the Early Miocene (16.5 ma) and therefore has been investigated extensively by scientists in the past decades. An exceptional discovery was made in 2005: a large fossil oyster reef has been excavated and documented carefully during the last years. Aside from the giant-sized oyster (Crassostrea gryphoides), the excavation site contains numerous species of molluscs along with teeth of sharks and rays and even isolated bones of sea cows. The oysters, having lengths of up to 80 cm, are protruding from the ground surface, which is more or less a tilted plane (25˚ ) with a size of about 300 m2. The entire site is crosscut by a network of geological faults, often also offsetting individual oyster shells. Displacements along the normal faults do not exceed ~ 15 cm. The faulted fossils offer a unique opportunity to measure displacement distribution along the faults in great detail and provide insight in deformation mechanisms in porous, barely lithified sediments. In order to get a precise 3D model of the oyster reef, the terrestrial laser scanner system Leica HDS 6000 is used. It is a phase-based laser scanner, i.e. the distance measurement is performed using the phase-shift principle. Compared to the time-of-flight principle, this method is generally more appropriate to projects like this one, where the distances to be measured are relatively small (< 35 m) and where a high point density (point spacing of about 1 cm) and precision (some mm) is required for capturing the oysters adequately. However, due to fact that they occlude each other, one single scan is not sufficient to get all sides of their surface. Therefore, scans from different positions had to be acquired. These scans have to be merged, which involves the problem of sensor orientation as well as sampling of the entire 3D point cloud. Furthermore, a representation of the surface data is required that

  8. Oysters produce an organic-inorganic adhesive for intertidal reef construction.

    PubMed

    Burkett, Jeremy R; Hight, Lauren M; Kenny, Paul; Wilker, Jonathan J

    2010-09-15

    Coastal ecosystems rely upon oyster reefs to filter water, provide protection from storms, and build habitat for other species. From a chemistry perspective, few details are available to illustrate how these shellfish construct such extensive reef systems. Experiments presented here show that oysters generate a biomineralized adhesive material for aggregating into large communities. This cement is an organic-inorganic hybrid and differs from the surrounding shells by displaying an alternate CaCO(3) crystal form, a cross-linked organic matrix, and an elevated protein content. Emerging themes and unique aspects are both revealed when comparing oyster cement to the adhesives of other marine organisms. The presence of cross-linked proteins provides an analogy to mussel and barnacle adhesives whereas the high inorganic content is exclusive to oysters. With a description of oyster cement in hand we gain strategies for developing synthetic composite materials as well as a better understanding of the components needed for healthy coastal environments.

  9. Passive acoustics as a monitoring tool for evaluating oyster reef restoration

    NASA Astrophysics Data System (ADS)

    Zenil Becerra, Hilde P.

    Oyster reefs are biodiverse communities that provide many ecological and commercial benefits. However, oyster reefs have declined around the world from human activities. Oyster reef restoration programs have begun to limit some of the decline, but the need for determining the success of a program has been problematic. Passive acoustic techniques can use naturally occurring sounds produced by organisms to assess biodiversity. Passive acoustics was utilized to compare the sounds in natural and restored oyster reefs, with special attention on snapping shrimp (Alpheus spp.) snap sounds, in the St. Lucie Estuary, Florida over a one year period. Season, estuary region, habitat and day period had an effect on sound production Passive acoustic monitoring of snapping shrimp sound production may be a useful non-destructive technique for monitoring the progress of oyster reef restoration projects once further correlations are established between environmental effects and sound production.

  10. Crassaostrea gigas oyster shell extract inhibits lipogenesis via suppression of serine palmitoyltransferase.

    PubMed

    Tran, Nguyen Khoi Song; Kwon, Jeong Eun; Kang, Se Chan; Shim, Soon-Mi; Park, Tae-Sik

    2015-02-01

    Oysters are widely consumed seafood, but their shells impose a serious environmental problem. To extend the utilization of oyster shell waste, we investigated the biological role of oyster shell extract. In this study, we verified that the ethanol extract of oyster shell (EOS) contains taurine and betaine, the major components of oyster body. EOS downregulated transcription of Sptlc1 and Sptlc2 mRNA, the subunits of serine palmitoyltransferase (SPT). Suppression of SPT subunits reduced sphinganine and sphingomyelin by inhibiting de novo sphingolipid biosynthesis. Inhibition of sphingomyelin biosynthesis resulted in downregulation of lipogenic gene expression such as ACC, FAS, SCD1, and DGAT2. Consistent with inhibition of lipogenesis, cellular triglyceride levels were diminished by EOS, but cholesterol levels were not altered. Taken together, these results suggest that EOS has a lipid-lowering effect and could be applied as either a therapeutic or preventive measure for metabolic dysfunction.

  11. Viability and release of Salmonella charity and Escherichia coli from oyster feces.

    PubMed Central

    Rowse, A J; Fleet, G H

    1982-01-01

    Sydney Rock oysters (Crassostrea commercialis) contaminated with Salmonella charity and Escherichia coli produced feces containing viable cells of these species. The level of these bacteria in the feces depended upon the level of oyster contamination. Both S. charity and E. coli were released from the feces into overlying seawater. The extent of release into seawater depended upon the physical state of the fecal material, water temperature, and the time of contact with the water. The viability of S. charity and E. coli associated with the feces and released into seawater decreased with time and was a function of seawater temperature. The association and release of bacteria from oyster feces has important implications in oyster purification and purification tank design and may lead to a recontamination of purified oysters. PMID:6753743

  12. Structural and compositional characterization of the adhesive produced by reef building oysters.

    PubMed

    Alberts, Erik M; Taylor, Stephen D; Edwards, Stephanie L; Sherman, Debra M; Huang, Chia-Ping; Kenny, Paul; Wilker, Jonathan J

    2015-04-29

    Oysters have an impressive ability to overcome difficulties of life within the stressful intertidal zone. These shellfish produce an adhesive for attaching to each other and building protective reef communities. With their reefs often exceeding kilometers in length, oysters play a major role in balancing the health of coastal marine ecosystems. Few details are available to describe oyster adhesive composition or structure. Here several characterization methods were applied to describe the nature of this material. Microscopy studies indicated that the glue is comprised of organic fiber-like and sheet-like structures surrounded by an inorganic matrix. Phospholipids, cross-linking chemistry, and conjugated organics were found to differentiate this adhesive from the shell. Symbiosis in material synthesis could also be present, with oysters incorporating bacterial polysaccharides into their adhesive. Oyster glue shows that an organic-inorganic composite material can provide adhesion, a property especially important when constructing a marine ecosystem.

  13. Eastern oyster (Crassostrea virginica) δ15N as a bioindicator of nitrogen sources: Observations and modeling

    PubMed Central

    Fertig, B.; Carruthers, T.J.B.; Dennison, W.C.; Fertig, E.J.; Altabet, M.A.

    2013-01-01

    Stable nitrogen isotopes (δ15N) in bioindicators are increasingly employed to identify nitrogen sources in many ecosystems and biological characteristics of the eastern oyster (Crassostrea virginica) make it an appropriate species for this purpose. To assess nitrogen isotopic fractionation associated with assimilation and baseline variations in oyster mantle, gill, and muscle tissue δ15N, manipulative fieldwork in Chesapeake Bay and corresponding modeling exercises were conducted. This study (1) determined that five individuals represented an optimal sample size; (2) verified that δ15N in oysters from two locations converged after shared deployment to a new location reflecting a change in nitrogen sources; (3) identified required exposure time and temporal integration (four months for muscle, two to three months for gill and mantle); and (4) demonstrated seasonal δ15N increases in seston (summer) and oysters (winter). As bioindicators, oysters can be deployed for spatial interpolation of nitrogen sources, even in areas lacking extant populations. PMID:20381097

  14. Survey for protozoan parasites in Eastern oysters (Crassostrea virginica) from the Gulf of Maine using PCR-based assays.

    PubMed

    Marquis, Nicholas D; Record, Nicholas R; Robledo, José A Fernández

    2015-10-01

    Protozoan pathogens represent a serious threat to oyster aquaculture, since they can lead to significant production loses. Moreover, oysters can concentrate human pathogens through filter feeding, thus putting at risk raw oyster consumers' health. Using PCR-based assays in oysters (Crassostrea virginica) from Maine, we expand the Northeast range in the USA for the protozoans Perkinsus marinus, Perkinsus chesapeaki, and Haplosporidium nelsoni, and report for the first time the detection of the human pathogens Toxoplasma gondii and Cryptosporidium parvum. Oysters hosting both P. marinus and P. chesapeaki were more than three times as likely to be infected by a non-Perkinsus than those free of Perkinsus infections.

  15. Defining optimal freshwater flow for oyster production: effects of freshet rate and magnitude of change and duration on eastern oysters and Perkinsus marinus infection

    USGS Publications Warehouse

    LaPeyre, Megan K.; Gossman, B.; La Peyre, Jerome F.

    2009-01-01

    In coastal Louisiana, the development of large-scale freshwater diversion projects has led to controversy over their effects on oyster resources. Using controlled laboratory experiments in combination with a field study, we examined the effects of pulsed freshwater events (freshet) of different magnitude, duration, and rate of change on oyster resources. Laboratory and field evidence indicate that low salinity events (<5 psu) decreased Perkinsus marinus infection intensities. Furthermore, when salinity was low (<5 psu), parasite infection intensities continued to decrease even as temperatures exceeded 20°C. At the same time, oyster growth was positively correlated with salinity. To maximize oyster production, data indicate that both low and high salinity events will be necessary.

  16. [Reproductive cycle of the mangrove oyster Crassostrea rhizophorae (Bivalvia: Ostreidae) in Camamu Bay, Bahia, Brasil].

    PubMed

    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.

  17. Biotransformation and detoxification of inorganic arsenic in Bombay oyster Saccostrea cucullata.

    PubMed

    Zhang, Wei; Guo, Zhiqiang; Zhou, Yanyan; Liu, Huaxue; Zhang, Li

    2015-01-01

    Arsenic (As) exists as the toxic inorganic forms in marine water and sediment, while marine oysters usually accumulate high As contents mostly as the less toxic organic forms. It has not yet been clear that how As is biotransformed in marine oysters. This study therefore investigated the biotransformation and detoxification of two inorganic As forms (As(III) and As(V)) in Bombay oyster Saccostrea cucullata after waterborne exposures for 30 days. Seven treatments of dissolved As exposure (clean seawater, 1, 5, 20 mg/L As(III), and 1, 5, 20 mg/L As(V)) were performed. Body As concentration increased significantly after all As exposure treatments except 1mg/L As(V). Total As, As(III), and As(V) concentration were positive correlated with glutathione-S-transferases (GST) activities, suggesting GST might play an important role in the As biotransformation and detoxification process. Organic As species were predominant in control and the low As exposed oysters, whereas a large fraction of As was remained as the inorganic forms in the high As exposed oysters, suggesting As could be biotransformed efficiently in the oysters in clean or light contaminated environment. The results of As speciation demonstrated the As biotransformation in the oysters included As(V) reduction, methylation to monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), and subsequent conversion to arsenobetaine (AsB). More As was distributed in the subcellular metallothionein-like proteins fraction (MTLP) functioning sequestration and detoxification in the inorganic As exposed oysters, suggesting it was also a strategy for oysters against As stress. In summary, this study elucidated that marine oysters had high ability to accumulate, biotransform, and detoxify inorganic As.

  18. The Effect of Oyster Reef Morphology on Particulate Transfer in a North Carolina Tidal Creek

    NASA Astrophysics Data System (ADS)

    Lemon, M. G.; Posey, M.; Mallin, M.; Alphin, T.

    2014-12-01

    The eastern oyster (Crassostrea virginica) is a vital ecosystem engineer species, providing a number of ecosystem services that structure and maintain estuarine environments through the construction of large, hard-bottom reef complexes. Through suspension feeding, oysters clear the water column of particulates, leading to decreased suspended material and enhanced benthic pelagic coupling. Past field studies have indicated the potential importance of the physical reef structure in regulating the transfer of particulate material in the seston. In order to directly assess the existence of the physical reef effect, multiple field experiments were performed in a small tidal creek estuary along the south eastern coast of North Carolina. Comparison of clearance rates derived from two different in situ methods, one accounting for the physical structure of the oyster reef in addition to oyster filtration and one looking at oyster filtration alone, indicate that the reef structure may increase the amount of particulate removal performed by the reef by more than 4 times the removal performed by oyster filtration alone. A defaunation experiment was performed by eliminating the live component of the oyster reef and comparing particulate transfer of this defaunated transect to that of an adjacent faunated transect. The defaunated transect had reduced but not significantly lower material removal when compared to the faunated transect prior to defaunation. Results from short and long term sediment collection and flow velocity measurements indicate that the physical effect of oyster reefs is strong over short temporal scales (days) but is much smaller when evaluated over longer time periods (months). Generally, large silt and small sand sized material is permanently removed from the seston due to the interaction of oyster reef structure and tidal flows, however the transfer of small and medium sized silt grains is only slowed down by the presence of large reef complexes. This

  19. Cloning and characterization of neoplasia-related genes in flat oyster Ostrea edulis.

    PubMed

    Martín-Gómez, Laura; Villalba, Antonio; Carballal, María Jesús; Abollo, Elvira

    2014-04-01

    Bonamiosis and disseminated neoplasia (DN) are the most important diseases affecting cultured flat oysters Ostrea edulis in Galicia (NW Spain). Previous research using suppresive substraction hybridisation that had been performed addressing the molecular basis of DN as well as the induction and development of the disease in oysters, yielded the whole open reading frame of nine genes: XBP-1, RACK, NDPk, C1qTNF, RPA3, SAP18, p23, ubiquitin and ferritin. These nine genes were characterized in this study. The phylogenetic relationships for each gene were studied using minimum-evolution methods. Quantitative-PCR assays were also developed to analyse the modulation of the expression of these genes by bonamiosis and disseminated neoplasia. Gene expression profiles were studied in haemolymph cells and in various organs (gill, gonad, mantle and digestive gland) of oysters affected by bonamiosis, disseminated neoplasia, both diseases and in non-affected oysters (control). The expression of XBP-1, NDPk, RPA3, SAP18 and ferritin increased in haemolymph cells of oysters with heavy bonamiosis. The expression of C1qTNF; SAP18 and p23 increased in haemolymph cells of oysters with DN. The expression of XBP-1, RACK, NDPk, RPA3 and p23 significantly increased in haemolymph cells of oysters affected by both diseases. There were changes in the expression of a number of genes in different organs depeding on disease stage: RACK expression increased in gills of oysters with bonamiosis, XBP-1 increased in mantle and digestive organs of oysters with light DN and RPA3 expression increased in gonads of oysters with heavy bonamiosis and heavy neoplasia.

  20. Intertidal oysters reach their physiological limit in a future high-CO2 world.

    PubMed

    Scanes, Elliot; Parker, Laura M; O'Connor, Wayne A; Stapp, Laura S; Ross, Pauline M

    2017-03-01

    Sessile marine molluscs living in the intertidal zone experience periods of internal acidosis when exposed to air (emersion) during low tide. Relative to other marine organisms, molluscs have been identified as vulnerable to future ocean acidification; however, paradoxically it has also been shown that molluscs exposed to high CO2 environments are more resilient compared with those molluscs naive to CO2 exposure. Two competing hypotheses were tested using a novel experimental design incorporating tidal simulations to predict the future intertidal limit of oysters in a high-CO2 world; either high-shore oysters will be more tolerant of elevated PCO2 because of their regular acidosis, or elevated PCO2  will cause high-shore oysters to reach their limit. Sydney rock oysters, Saccostrea glomerata, were collected from the high-intertidal and subtidal areas of the shore and exposed in an orthogonal design to either an intertidal or a subtidal treatment at ambient or elevated PCO2 , and physiological variables were measured. The combined treatment of tidal emersion and elevated PCO2  interacted synergistically to reduce the haemolymph pH (pHe) of oysters, and increase the PCO2  in the haemolymph (Pe,CO2 ) and standard metabolic rate. Oysters in the intertidal treatment also had lower condition and growth. Oysters showed a high degree of plasticity, and little evidence was found that intertidal oysters were more resilient than subtidal oysters. It is concluded that in a high-CO2 world the upper vertical limit of oyster distribution on the shore may be reduced. These results suggest that previous studies on intertidal organisms that lacked tidal simulations may have underestimated the effects of elevated PCO2.

  1. Microbial quality of oysters sold in Western Trinidad and potential health risk to consumers.

    PubMed Central

    Rampersad, F. S.; Laloo, S.; La Borde, A.; Maharaj, K.; Sookhai, L.; Teelucksingh, J.; Reid, S.; McDougall, L.; Adesiyun, A. A.

    1999-01-01

    The prevalence and characteristics of Escherichia coli and Salmonella spp. as well as counts of E. coli in raw oysters, condiments/spices, and raw oyster cocktails sampled from 72 vendors across Western Trinidad were determined. The microbial quality of the water used in the preparation of raw oysters was also investigated. Of 200 samples each of raw oysters, condiments/spices and oyster cocktails tested, 154 (77.0%), 89 (44.5%) and 154 (77.0%) respectively yielded E. coli. The differences were statistically significant (P = < 0.001; chi square = 62.91). The mean E. coli count per g in the ready-to-eat oyster cocktail ranged from 1.5 x 10(3) +/- 2.7 x 10(3) in Couva to 8.7x10(6) +/- 4.9x10(7) in San Fernando. One hundred and forty-six (73.0%) oyster cocktails contaminated with E. coli had counts that exceeded the recommended standard of 16 per g. Of a total of 590 E. coli isolates from various sources tested, 24 (4.1%), 20 (3.4%) and 69 (11.7%) were mucoid, haemolytic and non-sorbitol fermenters respectively. Twelve (2.0%) isolates of E. coli were O157 strains, while 92 (46.0%) of 200 E. coli isolates tested belonged to enteropathogenic serogroups. Ninety (45.0%) and 73 (36.5%) of 200 water samples contained total coliforms and faecal coliforms respectively, with counts that exceeded 2.2 coliforms per 100 ml. Salmonella spp. were isolated from 7 (3.5%), 1 (0.5%) and 2 (1.0%) of 200 samples each, of raw oysters, condiments/spices and oyster cocktails respectively. Oysters pose a health risk to consumers in Trinidad, particularly from colibacillosis and salmonellosis, and the need for increased public awareness of this hazard cannot be over-emphasized. PMID:10579443

  2. High Salinity Relaying to Reduce Vibrio parahaemolyticus and Vibrio vulnificus in Chesapeake Bay Oysters (Crassostrea virginica).

    PubMed

    Parveen, Salina; Jahncke, Michael; Elmahdi, Sara; Crocker, Helen; Bowers, John; White, Chanelle; Gray, Stephanie; Morris, Amanda C; Brohawn, Kathy

    2017-02-01

    Cases of Vibrio infections in the United States have tripled from 1996 to 2009 and these infections are most often associated with the consumption of seafood, particularly oysters (Crassostrea virginica). Information is needed on how to reduce numbers of Vibrio parahaemolyticus and Vibrio vulnificus in bi-valve molluscan shellfish (for example, oysters). The purpose of this study was to evaluate the effectiveness of high salinity relaying or treatment in recirculating aquaculture systems (RASs) as methods to reduce the abundance of V. parahaemolyticus and V. vulnificus in oysters. For relaying field trials, oysters were collected from approved harvest waters, temperature abused outside under a tarp for 4 h, and then transferred to high (29 to 33 ppt.) and moderate (12 to 19 ppt.) salinities. For RAS treatment trial, oysters were transferred to 32 to 34 ppt. salinity at 15 °C. After 7, 14, 21, and in some instances 28 d, oysters were collected and analyzed for V. parahaemolyticus and V. vulnificus levels using multiplex real-time PCR. Initial levels of V. parahaemolyticus and V. vulnificus ranged from 3.70 to 5.64 log10 MPN/g, and were reduced by 2 to 5 logs after 21 to 28 d in high salinity water (29 to 34 ppt.). Oyster mortalities averaged 4% or less, and did not exceed 7%. Relaying of oysters to high salinity field sites or transfer to high salinity RAS tanks was more effective in reducing V. vulnificus compared with V. parahaemolyticus. These results suggest that high salinity relaying of oysters is more effective in reducing V. vulnificus than V. parahaemolyticus in the oyster species used in this study.

  3. Influence of water allocation and freshwater inflow on oyster production: a hydrodynamic-oyster population model for Galveston Bay, Texas, USA.

    PubMed

    Powell, Eric N; Klinck, John M; Hofmann, Eileen E; McManus, Margaret A

    2003-01-01

    A hydrodynamic-oyster population model was developed to assess the effect of changes in freshwater inflow on oyster populations in Galveston Bay, Texas, USA. The population model includes the effects of environmental conditions, predators, and the oyster parasite, Perkinsus marinus, on oyster populations. The hydrodynamic model includes the effects of wind stress, river runoff, tides, and oceanic exchange on the circulation of the bay. Simulations were run for low, mean, and high freshwater inflow conditions under the present (1993) hydrology and predicted hydrologies for 2024 and 2049 that include both changes in total freshwater inflow and diversions of freshwater from one primary drainage basin to another. Freshwater diversion to supply the Houston metropolitan area is predicted to negatively impact oyster production in Galveston Bay. Fecundity and larval survivorship both decline. Mortality from Perkinsus marinus increases, but to a lesser extent. A larger negative impact in 2049 relative to 2024 originates from the larger drop in fecundity under that hydrology. Changes in recruitment and mortality, resulting in lowered oyster abundance, occur because the bay volume available for mixing freshwater input from the San Jacinto and Buffalo Bayou drainage basins that drain metropolitan Houston is small in comparison to the volume of Trinity Bay that presently receives the bulk of the bay's freshwater inflow. A smaller volume for mixing results in salinities that decline more rapidly and to a greater extent under conditions of high freshwater discharge.Thus, the decline in oyster abundance results from a disequilibrium between geography and salinity brought about by freshwater diversion. Although the bay hydrology shifts, available hard substrate does not. The simulations stress the fact that it is not just the well-appreciated reduction in freshwater inflow that can result in decreased oyster production. Changing the location of freshwater inflow can also

  4. Transcriptome of American oysters, Crassostrea virginica, in response to bacterial challenge: insights into potential mechanisms of disease resistance.

    PubMed

    McDowell, Ian C; Nikapitiya, Chamilani; Aguiar, Derek; Lane, Christopher E; Istrail, Sorin; Gomez-Chiarri, Marta

    2014-01-01

    The American oyster Crassostrea virginica, an ecologically and economically important estuarine organism, can suffer high mortalities in areas in the Northeast United States due to Roseovarius Oyster Disease (ROD), caused by the gram-negative bacterial pathogen Roseovarius crassostreae. The goals of this research were to provide insights into: 1) the responses of American oysters to R. crassostreae, and 2) potential mechanisms of resistance or susceptibility to ROD. The responses of oysters to bacterial challenge were characterized by exposing oysters from ROD-resistant and susceptible families to R. crassostreae, followed by high-throughput sequencing of cDNA samples from various timepoints after disease challenge. Sequence data was assembled into a reference transcriptome and analyzed through differential gene expression and functional enrichment to uncover genes and processes potentially involved in responses to ROD in the American oyster. While susceptible oysters experienced constant levels of mortality when challenged with R. crassostreae, resistant oysters showed levels of mortality similar to non-challenged oysters. Oysters exposed to R. crassostreae showed differential expression of transcripts involved in immune recognition, signaling, protease inhibition, detoxification, and apoptosis. Transcripts involved in metabolism were enriched in susceptible oysters, suggesting that bacterial infection places a large metabolic demand on these oysters. Transcripts differentially expressed in resistant oysters in response to infection included the immune modulators IL-17 and arginase, as well as several genes involved in extracellular matrix remodeling. The identification of potential genes and processes responsible for defense against R. crassostreae in the American oyster provides insights into potential mechanisms of disease resistance.

  5. D Central Line Extraction of Fossil Oyster Shells

    NASA Astrophysics Data System (ADS)

    Djuricic, A.; Puttonen, E.; Harzhauser, M.; Mandic, O.; Székely, B.; Pfeifer, N.

    2016-06-01

    Photogrammetry provides a powerful tool to digitally document protected, inaccessible, and rare fossils. This saves manpower in relation to current documentation practice and makes the fragile specimens more available for paleontological analysis and public education. In this study, high resolution orthophoto (0.5 mm) and digital surface models (1 mm) are used to define fossil boundaries that are then used as an input to automatically extract fossil length information via central lines. In general, central lines are widely used in geosciences as they ease observation, monitoring and evaluation of object dimensions. Here, the 3D central lines are used in a novel paleontological context to study fossilized oyster shells with photogrammetric and LiDAR-obtained 3D point cloud data. 3D central lines of 1121 Crassostrea gryphoides oysters of various shapes and sizes were computed in the study. Central line calculation included: i) Delaunay triangulation between the fossil shell boundary points and formation of the Voronoi diagram; ii) extraction of Voronoi vertices and construction of a connected graph tree from them; iii) reduction of the graph to the longest possible central line via Dijkstra's algorithm; iv) extension of longest central line to the shell boundary and smoothing by an adjustment of cubic spline curve; and v) integration of the central line into the corresponding 3D point cloud. The resulting longest path estimate for the 3D central line is a size parameter that can be applied in oyster shell age determination both in paleontological and biological applications. Our investigation evaluates ability and performance of the central line method to measure shell sizes accurately by comparing automatically extracted central lines with manually collected reference data used in paleontological analysis. Our results show that the automatically obtained central line length overestimated the manually collected reference by 1.5% in the test set, which is deemed

  6. Improving early detection of exotic or emergent oyster diseases in France: identifying factors associated with shellfish farmer reporting behaviour of oyster mortality.

    PubMed

    Lupo, C; Osta Amigo, A; Mandard, Y V; Peroz, C; Renault, T

    2014-09-01

    Farmers' vigilance is essential for the detection of epidemics, including potential emerging diseases, in marine shellfish. A field study was conducted to investigate oyster farmers' reporting practices and behaviour, and to identify factors influencing the reporting process of oyster mortality, with the ultimate aim of improving early detection of unexplained oyster mortality outbreaks. A retrospective case-control study of oyster farmers from Charente-Maritime (France) was designed, based on interviews with 27 non-reporting and 89 reporting farmers, further split into 40 formerly-reporting and 49 currently-reporting farmers. Information about farmer and farm characteristics, farming practices, farm health history and related financial compensation on the farm, knowledge of the mortality reporting system and reporting behaviour was collected. Sampling design was considered in the calculations and farmers' reporting behaviour was modelled using an ordinal logistic regression (continuation-ratio model). Notification procedures were fairly well known among farmers and the reporting system was well accepted overall. Nevertheless, a lack of awareness of the aims of the reporting system was revealed, which contributed to late reporting. Factors identified as driving a farmer's decision to report oyster mortality concerned their lack of awareness of mortality reporting (production type, farm size, location of the production cycle, accessibility of the leasing grounds) and willingness to report (possibility and extent of financial compensation, a feeling of not being involved, whether it was first year of reporting). Overall classification performance of the model built in this study was 64%. In particular, financial compensation for oyster production losses appeared to be a clear incentive for reporting, but was countered by a habituation effect combined with a lack of awareness of the aims of the reporting system: oyster farmers looking for benefits for themselves in

  7. Pleurostrin, an antifungal peptide from the oyster mushroom.

    PubMed

    Chu, K T; Xia, Lixin; Ng, T B

    2005-11-01

    A 7kDa peptide, with inhibitory activity on mycelial growth in the fungi Fusaerium oxysporum, Mycosphaerella arachidicola and Physalospora piricola, was isolated from fresh fruiting bodies of the oyster mushroom. The isolation procedure entailed extraction with an aqueous buffer, ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel and gel filtration by fast protein liquid chromatography on Superdex 75. The protein was unadsorbed on DEAE-cellulose and adsorbed on Affi-gel blue gel. It demonstrated an N-terminal sequence different from known antifungal proteins and peptides.

  8. Fishing down the coast: historical expansion and collapse of oyster fisheries along continental margins.

    PubMed

    Kirby, Michael Xavier

    2004-08-31

    Estuarine ecosystems have changed dramatically from centuries of fishing, habitat disturbance, sedimentation, and nutrient loading. Degradation of oyster reefs by destructive fishing practices in particular has had a profound effect on estuarine ecology, yet the timing and magnitude of oyster-reef degradation in estuaries is poorly quantified. Here, I evaluate the expansion and collapse of oyster fisheries in 28 estuaries along three continental margins through the analysis of historical proxies derived from fishery records to infer when oyster reefs were degraded. Exploitation for oysters did not occur randomly along continental margins but followed a predictable pattern. Oyster fisheries expanded and collapsed in a linear sequence along eastern North America (Crassostrea virginica), western North America (Ostreola conchaphila), and eastern Australia (Saccostrea glomerata). Fishery collapse began in the estuaries that were nearest to a developing urban center before exploitation began to spread down the coast. As each successive fishery collapsed, oysters from more distant estuaries were fished and transported to restock exploited estuaries near the original urban center. This moving wave of exploitation traveled along each coastline until the most distant estuary had been reached and overfished.

  9. Angiotensin I-converting enzyme inhibitor derived from cross-linked oyster protein.

    PubMed

    Xie, Cheng-Liang; Kim, Jin-Soo; Ha, Jong-Myung; Choung, Se-Young; Choi, Yeung-Joon

    2014-01-01

    Following cross-linking by microbial transglutaminase, modified oyster proteins were hydrolyzed to improve inhibitory activity against angiotensin-converting enzyme (ACE) inhibitory activity with the use of a single protease, or a combination of six proteases. The oyster hydrolysate with the lowest 50% ACE inhibitory concentration (IC50) of 0.40 mg/mL was obtained by two-step hydrolysis of the cross-linked oyster protein using Protamex and Neutrase. Five ACE inhibitory peptides were purified from the oyster hydrolysate using a multistep chromatographic procedure comprised of ion-exchange, size exclusion, and reversed-phase liquid chromatography. Their sequences were identified as TAY, VK, KY, FYN, and YA, using automated Edman degradation and mass spectrometry. These peptides were synthesized, and their IC50 values were measured to be 16.7, 29.0, 51.5, 68.2, and 93.9 μM, respectively. Toxicity of the peptides on the HepG2 cell line was not detected. The oyster hydrolysate also significantly decreased the systolic blood pressure of spontaneously hypertensive rats (SHR). The antihypertensive effect of the oyster hydrolysate on SHR was rapid and long-lasting, compared to commercially obtained sardine hydrolysate. These results suggest that the oyster hydrolysate could be a source of effective nutraceuticals against hypertension.

  10. Effects of oyster harvest activities on Louisiana reef habitat and resident nekton communities

    USGS Publications Warehouse

    Beck, Steve; LaPeyre, Megan K.

    2015-01-01

    Oysters are often cited as “ecosystem engineers” because they modify their environment. Coastal Louisiana contains extensive oyster reef areas that have been harvested for decades, and whether differences in habitat functions exist between those areas and nonharvested reefs is unclear. We compared reef physical structure and resident community metrics between these 2 subtidal reef types. Harvested reefs were more fragmented and had lower densities of live eastern oysters (Crassostrea virginica) and hooked mussels (Ischadium recurvum) than the nonharvested reefs. Stable isotope values (13C and 15N) of dominant nekton species and basal food sources were used to compare food web characteristics. Nonpelagic source contributions and trophic positions of dominant species were slightly elevated at harvested sites. Oyster harvesting appeared to have decreased the number of large oysters and to have increased the percentage of reefs that were nonliving by decreasing water column filtration and benthopelagic coupling. The differences in reef matrix composition, however, had little effect on resident nekton communities. Understanding the thresholds of reef habitat areas, the oyster density or oyster size distribution below which ecosystem services may be compromised, remains key to sustainable management.

  11. The role of tissue-specific microbiota in initial establishment success of Pacific oysters.

    PubMed

    Lokmer, Ana; Kuenzel, Sven; Baines, John F; Wegner, Karl Mathias

    2016-03-01

    Microbiota can have positive and negative effects on hosts depending on the environmental conditions. Therefore, it is important to decipher host-microbiota-environment interactions, especially under natural conditions exerting (a)biotic stress. Here, we assess the relative importance of microbiota in different tissues of Pacific oyster for its successful establishment in a new environment. We transplanted oysters from the Southern to the Northern Wadden Sea and controlled for the effects of resident microbiota by administering antibiotics to half of the oysters. We then followed survival and composition of haemolymph, mantle, gill and gut microbiota in local and translocated oysters over 5 days. High mortality was recorded only in non-antibiotic-treated translocated oysters, where high titres of active Vibrio sp. in solid tissues indicated systemic infections. Network analyses revealed the highest connectivity and a link to seawater communities in the haemolymph microbiota. Since antibiotics decreased modularity and increased connectivity of the haemolymph-based networks, we propose that community destabilization in non-treated translocated oysters could be attributed to interactions between resident and external microbiota, which in turn facilitated passage of vibrios into solid tissues and invoked disease. These interactions of haemolymph microbiota with the external and internal environment may thus represent an important component of oyster fitness.

  12. Introduction, establishment and expansion of the Pacific oyster Crassostrea gigas in the Oosterschelde (SW Netherlands)

    NASA Astrophysics Data System (ADS)

    Smaal, A. C.; Kater, B. J.; Wijsman, J.

    2009-03-01

    The Pacific oyster Crassostrea gigas was first introduced as an exotic species by oyster farmers in 1964 in the Oosterschelde estuary (SW Netherlands). The initial phase is not well documented but first natural spatfall was recorded in 1975. Excessive spatfall occurred in 1976 and this is considered the start of the expansion phase of the wild oysters. Oyster beds in intertidal and subtidal areas of the Oosterschelde estuary have been growing since. The development in the intertidal area has been reconstructed by using aerial photography, validated by ground truth in 2000-2002. In the subtidal areas extensive oyster beds have been detected by using side scan sonar; on hard substrates along the dikes coverage with oysters up to 90% locally has been recorded by scuba diving surveys. Expansion has also occurred into adjacent water bodies including the Wadden Sea. By forming resistant reefs the oysters induce structural changes in the ecosystem. It is concluded that bed area is still expanding while decrease of the fraction live animals may indicate adjustment of the stock size to the local conditions.

  13. Epizootiology of Perkinsus sp. inCrassostrea gasar oysters in polyculture with shrimps in northeastern Brazil.

    PubMed

    da Silva, Patricia Mirella; Costa, Carolina Pereira; de Araújo, Jaíse Paiva Bragante; Queiroga, Fernando Ramos; Wainberg, Alexandre Alter

    2016-01-01

    Bivalve culture is of considerable economic and social interest in northeastern (NE) Brazil. The polyculture is an alternative approach to traditional monoculture for reducing the environmental impact of shrimp farming and improving oyster culture. Perkinsus marinus and Perkinsus olseni were found infecting oysters in NE Brazil and can threaten oyster production. This study evaluated Perkinsus spp. occurrence in Crassostrea gasar during all production stages. Oyster spats were produced in a hatchery and grown in shrimp ponds in Rio Grande do Norte state. Perkinsus spp. were surveyed by Ray's fluid thioglycollate medium and confirmed by polymerase chain reaction. Prevalence and intensity of infection were determined in oysters until they reached 7 cm. Results showed that the broodstock was already infected by Perkinsus (60%), but the derived spats were Perkinsus-free. Oyster spats acquired Perkinsus infection when transferred to ponds. The prevalence gradually increased in the seven months following placement in ponds (73%), and then decreased to 17% by the tenth month. The infections were initially mild, but intensity increased at the final growth stage. In conclusion, it is possible to produce Perkinsus-free C. gasar oyster spats from infected broodstock, and their culture in shrimp ponds is feasible.

  14. Annual dose of Taiwanese from the ingestion of 210Po in oysters.

    PubMed

    Lee, Hsiu-wei; Wang, Jeng-Jong

    2013-03-01

    Oysters around the coast of Taiwan were collected, dried, spiked with a (209)Po tracer for yield, digested with concentrated HNO(3) and H(2)O(2), and finally dissolved in 0.5 N HCl. The polonium was then spontaneously deposited onto a silver disc, and the activity of (210)Po was measured using an alpha spectrum analyzer equipped with a silicon barrier detector. Meanwhile, the internal effective dose of (210)Po coming from the intake of oysters by Taiwanese was evaluated. The results of the present study indicate that (210)Po average activity concentrations ranged from 23.4 ± 0.4 to 126 ± 94 Bq kg(-1) of fresh oysters. The oysters coming from Penghu island and Kinmen island regions contain higher concentrations of (210)Po in comparison with oysters from other regions of Taiwan. The value of (210)Po weighted average activity concentrations for all oyster samples studied is 25.9 Bq kg(-1). The annual effective dose of Taiwanese due to the ingestion of (210)Po in oysters was estimated to be 4.1 × 10(-2) mSv y(-1).

  15. Increases in the amounts of Vibrio spp. in oysters upon addition of exogenous bacteria.

    PubMed

    Froelich, Brett; Oliver, James

    2013-09-01

    The bacterial pathogen Vibrio vulnificus is found naturally in brackish coastal waters but can be greatly concentrated by filter-feeding organisms such as shellfish. Numerous experiments in which exogenous V. vulnificus cells are added to oysters in an attempt to measure uptake and depuration have been performed. In nearly all cases, results have shown that laboratory-grown bacteria are rapidly taken up by the oysters but ultimately eliminated, while naturally present Vibrio populations in oysters are resistant to depuration. In this study, oysters harvested during winter months, with low culturable Vibrio concentrations, were incubated in aquaria supplemented with strains of V. vulnificus that were either genotypically or phenotypically distinct from the background bacteria. These exogenous cells were eliminated from the oysters, as previously seen, but other vibrios already inhabiting the oysters responded to the V. vulnificus inoculum by rapidly increasing in number and maintaining a large stable population. The presence of such an oyster-adapted Vibrio population would be expected to prevent colonization by exogenous V. vulnificus cells, thus explaining the rapid depuration of these added bacteria.

  16. Incorporation of metabolites into glycogen and lipids of the oyster, crassostrea virginica

    SciTech Connect

    Swift, M.L.; Humphrey, C.L. )

    1987-05-01

    Groups of oysters, either fed or unfed, were exposed to U-{sup 14}C labelled D-glucose, L-asp, L-leu, L-ala or acetate for 6 hrs. Except for the glucose trials, the disappearance of radioactivity from the saline of the unfed oysters was greater (83%) than for the fed animals (65%). With glucose, 88% of the radioactivity disappeared in each trial. The specific radioactivity of glycogen isolated from oysters exposed to labelled glucose, asp and ala was 1283, 468 and 8.22 dpm/mg glycogen respectively. Radioactivity was found primarily in the triacylglycerols and phospholipids (PL) in fed oysters and in PL only in unfed oysters. Phosphatidyl choline, phosphatidyl ethanolamine, and a fraction containing phosphatidyl serine and phosphatidyl inositol, had 32%, 25% and 35-40% of the radioactivity respectively. Incorporation of total radioactivity into PL was 70% lower in unfed vs. fed trials, but the distribution of counts among the phospholipids classes was unchanged. Glycogenesis does not appear to be a significant pathway in the oyster. Apparently well-fed oysters are able to store excess dietary calories as lipid. During periods of starvation exogenous small metabolites along with glucose from glycogen are catabolized.

  17. Quantitative proteomics of heavy metal stress responses in Sydney rock oysters.

    PubMed

    Muralidharan, Sridevi; Thompson, Emma; Raftos, David; Birch, Gavin; Haynes, Paul A

    2012-03-01

    Currently, there are few predictive biomarkers in key biomonitoring species, such as oysters, that can detect heavy metal pollution in coastal waterways. Several attributes make oysters superior to other organisms for positive biomonitoring of heavy metal pollution. In particular, they are filter feeders with a high capacity for bioaccumulation. In this study, we used two proteomics approaches, namely label-free shotgun proteomics based on SDS-PAGE gel separation and gas phase fractionation, to investigate the heavy metal stress responses of Sydney rock oysters. Protein samples were prepared from haemolymph of oysters exposed to 100 μg/L of PbCl(2), CuCl(2), or ZnCl(2) for 4 days in closed aquaria. Peptides were identified using a Bivalvia protein sequence database, due to the unavailability of a complete oyster genome sequence. Statistical analysis revealed 56 potential biomarker proteins, as well as several protein biosynthetic pathways to be greatly impacted by metal stress. These have the potential to be incorporated into bioassays for prevention and monitoring of heavy metal pollution in Australian oyster beds. The study confirms that proteomic analysis of biomonitoring species is a promising approach for assessing the effects of environmental pollution, and our experiments have provided insights into the molecular mechanisms underlying oyster stress responses.

  18. Analysis of Stomach and Gut Microbiomes of the Eastern Oyster (Crassostrea virginica) from Coastal Louisiana, USA

    SciTech Connect

    King, Gary M.; Judd, Craig; Kuske, Cheryl R.; Smith, Conor

    2012-12-12

    In this paper, we used high throughput pyrosequencing to characterize stomach and gut content microbiomes of Crassostrea virginica, the Easter oyster, obtained from two sites, one in Barataria Bay (Hackberry Bay) and the other in Terrebonne Bay (Lake Caillou), Louisiana, USA. Stomach microbiomes in oysters from Hackberry Bay were overwhelmingly dominated by Mollicutes most closely related to Mycoplasma; a more rich community dominated by Planctomyctes occurred in Lake Caillou oyster stomachs. Gut communities for oysters from both sites differed from stomach communities, and harbored a relatively diverse assemblage of phylotypes. Phylotypes most closely related to Shewanella and a Chloroflexi strain dominated the Lake Caillou and Hackberry Bay gut microbiota, respectively. While many members of the stomach and gut microbiomes appeared to be transients or opportunists, a putative core microbiome was identified based on phylotypes that occurred in all stomach or gut samples only. The putative core stomach microbiome comprised 5 OTUs in 3 phyla, while the putative core gut microbiome contained 44 OTUs in 12 phyla. These results collectively revealed novel microbial communities within the oyster digestive system, the functions of the oyster microbiome are largely unknown. Finally, a comparison of microbiomes from Louisiana oysters with bacterial communities reported for other marine invertebrates and fish indicated that molluscan microbiomes were more similar to each other than to microbiomes of polychaetes, decapods and fish.

  19. Analysis of Stomach and Gut Microbiomes of the Eastern Oyster (Crassostrea virginica) from Coastal Louisiana, USA

    DOE PAGES

    King, Gary M.; Judd, Craig; Kuske, Cheryl R.; ...

    2012-12-12

    In this paper, we used high throughput pyrosequencing to characterize stomach and gut content microbiomes of Crassostrea virginica, the Easter oyster, obtained from two sites, one in Barataria Bay (Hackberry Bay) and the other in Terrebonne Bay (Lake Caillou), Louisiana, USA. Stomach microbiomes in oysters from Hackberry Bay were overwhelmingly dominated by Mollicutes most closely related to Mycoplasma; a more rich community dominated by Planctomyctes occurred in Lake Caillou oyster stomachs. Gut communities for oysters from both sites differed from stomach communities, and harbored a relatively diverse assemblage of phylotypes. Phylotypes most closely related to Shewanella and a Chloroflexi strainmore » dominated the Lake Caillou and Hackberry Bay gut microbiota, respectively. While many members of the stomach and gut microbiomes appeared to be transients or opportunists, a putative core microbiome was identified based on phylotypes that occurred in all stomach or gut samples only. The putative core stomach microbiome comprised 5 OTUs in 3 phyla, while the putative core gut microbiome contained 44 OTUs in 12 phyla. These results collectively revealed novel microbial communities within the oyster digestive system, the functions of the oyster microbiome are largely unknown. Finally, a comparison of microbiomes from Louisiana oysters with bacterial communities reported for other marine invertebrates and fish indicated that molluscan microbiomes were more similar to each other than to microbiomes of polychaetes, decapods and fish.« less

  20. Parasites infecting the cultured oyster Crassostrea gasar (Adanson, 1757) in Northeast Brazil.

    PubMed

    Queiroga, Fernando Ramos; Vianna, Rogério Tubino; Vieira, Cairé Barreto; Farias, Natanael Dantas; Da Silva, Patricia Mirella

    2015-05-01

    The oyster Crassostrea gasar is a species widely used as food and a source of income for the local population of the estuaries of Northeast Brazil. Perkinsus marinus and Perkinsus olseni are deleterious parasites for oyster farming and were recently detected in Brazil. In this study, a histopathologic survey of the oyster C. gasar cultured in the estuary of the River Mamanguape (Paraíba State) was performed. Adult oysters were collected in December 2011 and March, May, August and October 2012 and processed for histology and Perkinsus sp. identification by molecular analyses. Histopathological analysis revealed the presence of parasitic organisms including viral gametocytic hypertrophy, prokaryote-like colonies, protozoans (Perkinsus sp. and Nematopsis sp.) and metazoans (Tylocephalum sp. and cestodes). Other commensal organisms were also detected (the protozoan Ancistrocoma sp. and the turbellarian Urastoma sp.). The protozoan parasite Perkinsus sp. had the highest overall prevalence among the symbiotic organisms studied (48.9%), followed by Nematopsis sp. (36.3%). The other organisms were only sporadically observed. Only the protozoan Perkinsus sp. caused alterations in the oysters' infected organs. Molecular analyses confirmed the presence of P. marinus, P. olseni and Perkinsus beihaiensis infecting the oyster C. gasar. This is the first report of P. beihaiensis in this oyster species.

  1. Influence of oyster culture on biogeochemistry and bacterial community structure at the sediment-water interface.

    PubMed

    Azandégbé, Afi; Poly, Franck; Andrieux-Loyer, Françoise; Kérouel, Roger; Philippon, Xavier; Nicolas, Jean-Louis

    2012-10-01

    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), respectively, in June 2007. At RA, the fluxes were about half as strong on average and better distributed through the year. The ammonia and sulfide concentrations in the overlying water never reached levels that would be toxic to oysters in either site, nor did hypoxia occur. Total culturable bacteria (TCB) varied greatly according to the temperature: from 1.6 × 10(4) to 9.4 × 10(7) cell g(-1) sediment. Inversely, the bacterial community structure remained surprising stable through the seasons, marginally influenced by the presence of oysters and by temperature. Bacterial communities appeared to be characteristic of the sites, with only one common phylotype, Vibrio aestuarianus, a potential oyster pathogen. These data refine the hypothesis of seawater toxicity to oysters because of ammonia and sulfide fluxes and show that the measured environmental factors had only a weak influence on bacterial community structure.

  2. A xenograft mantle transplantation technique for producing a novel pearl in an akoya oyster host.

    PubMed

    Fukushima, Ei; Iwai, Toshiharu; Miura, Chiemi; Celino, Fritzie T; Urasaki, Shintarou; Miura, Takeshi

    2014-02-01

    The brightness and color of pearls varies among different pearl-producing shellfish and have been a source of human fascination since ancient times. When produced through cultivation, the characteristics and quality of a pearl depend on the kind of shellfish used and also the transplanted mantle graft. This suggests that the Akoya pearl oyster, which is generally used in Japan for pearl culturing, can produce different kinds of pearl through the use of mantles from different species of shellfish. However, a transplanted heterogeneous mantle would be rejected by the immune system of the Akoya oyster. We have therefore developed a new method to suppress the Akoya immune system that archives immune tolerance to other shellfish. It is generally known that small quantities of antigens can be used to produce archived immunological tolerance in a clinical setting. We successfully suppressed the Akoya pearl oyster immune response against a Mabé pearl oyster graft through repeat injections of mantle homogenates. We then transplanted a Mabé pearl oyster mantle graft into the immunologically tolerant Akoya pearl oyster and obtained a Mabé pearl from an Akoya pearl oyster. Our new technique thus makes the production of novel and different pearls in the Akoya possible. We believe that this has significant future potential for the advancement of the pearl industry.

  3. The new insights into the oyster antimicrobial defense: Cellular, molecular and genetic view.

    PubMed

    Bachère, Evelyne; Rosa, Rafael Diego; Schmitt, Paulina; Poirier, Aurore C; Merou, Nicolas; Charrière, Guillaume M; Destoumieux-Garzón, Delphine

    2015-09-01

    Oysters are sessile filter feeders that live in close association with abundant and diverse communities of microorganisms that form the oyster microbiota. In such an association, cellular and molecular mechanisms have evolved to maintain oyster homeostasis upon stressful conditions including infection and changing environments. We give here cellular and molecular insights into the Crassostrea gigas antimicrobial defense system with focus on antimicrobial peptides and proteins (AMPs). This review highlights the central role of the hemocytes in the modulation and control of oyster antimicrobial response. As vehicles for AMPs and other antimicrobial effectors, including reactive oxygen species (ROS), and together with epithelia, hemocytes provide the oyster with local defense reactions instead of systemic humoral ones. These reactions are largely based on phagocytosis but also, as recently described, on the extracellular release of antimicrobial histones (ETosis) which is triggered by ROS. Thus, ROS can signal danger and activate cellular responses in the oyster. From the current literature, AMP production/release could serve similar functions. We provide also new lights on the oyster genetic background that underlies a great diversity of AMP sequences but also an extraordinary individual polymorphism of AMP gene expression. We discuss here how this polymorphism could generate new immune functions, new pathogen resistances or support individual adaptation to environmental stresses.

  4. Angiotensin I-Converting Enzyme Inhibitor Derived from Cross-Linked Oyster Protein

    PubMed Central

    Xie, Cheng-Liang; Kim, Jin-Soo; Ha, Jong-Myung; Choung, Se-Young

    2014-01-01

    Following cross-linking by microbial transglutaminase, modified oyster proteins were hydrolyzed to improve inhibitory activity against angiotensin-converting enzyme (ACE) inhibitory activity with the use of a single protease, or a combination of six proteases. The oyster hydrolysate with the lowest 50% ACE inhibitory concentration (IC50) of 0.40 mg/mL was obtained by two-step hydrolysis of the cross-linked oyster protein using Protamex and Neutrase. Five ACE inhibitory peptides were purified from the oyster hydrolysate using a multistep chromatographic procedure comprised of ion-exchange, size exclusion, and reversed-phase liquid chromatography. Their sequences were identified as TAY, VK, KY, FYN, and YA, using automated Edman degradation and mass spectrometry. These peptides were synthesized, and their IC50 values were measured to be 16.7, 29.0, 51.5, 68.2, and 93.9 μM, respectively. Toxicity of the peptides on the HepG2 cell line was not detected. The oyster hydrolysate also significantly decreased the systolic blood pressure of spontaneously hypertensive rats (SHR). The antihypertensive effect of the oyster hydrolysate on SHR was rapid and long-lasting, compared to commercially obtained sardine hydrolysate. These results suggest that the oyster hydrolysate could be a source of effective nutraceuticals against hypertension. PMID:25140307

  5. Nutrient bioassimilation capacity of aquacultured oysters: quantification of an ecosystem service.

    PubMed

    Higgins, Colleen B; Stephenson, Kurt; Brown, Bonnie L

    2011-01-01

    Like many coastal zones and estuaries, the Chesapeake Bay has been severely degraded by cultural eutrophication. Rising implementation costs and difficulty achieving nutrient reduction goals associated with point and nonpoint sources suggests that approaches supplemental to source reductions may prove useful in the future. Enhanced oyster aquaculture has been suggested as one potential policy initiative to help rid the Bay waters of excess nutrients via harvest of bioassimilated nutrients. To assess this potential, total nitrogen (TN), total phosphorous (TP), and total carbon (TC) content were measured in oyster tissue and shell at two floating-raft cultivation sites in the Chesapeake Bay. Models were developed based on the common market measurement of total length (TL) for aquacultured oysters, which was strongly correlated to the TN (R2 = 0.76), TP (R2 = 0.78), and TC (R2 = 0.76) content per oyster tissue and shell. These models provide resource managers with a tool to quantify net nutrient removal. Based on model estimates, 10(6) harvest-sized oysters (76 mm TL) remove 132 kg TN, 19 kg TP, and 3823 kg TC. In terms of nutrients removed per unit area, oyster harvest is an effective means of nutrient removal compared with other nonpoint source reduction strategies. At a density of 286 oysters m(-2), assuming no mortality, harvest size nutrient removal rates can be as high as 378 kg TN ha(-1), 54 kg TP ha(-1), and 10,934 kg TC ha(-1) for 76-mm oysters. Removing 1 t N from the Bay would require harvesting 7.7 million 76-mm TL cultivated oysters.

  6. Modeling and Prediction of Oyster Norovirus Outbreaks along Gulf of Mexico Coast

    PubMed Central

    Wang, Jiao; Deng, Zhiqiang

    2015-01-01

    Background: Oyster norovirus outbreaks often pose high risks to human health. However, little is known about environmental factors controlling the outbreaks, and little can be done to prevent the outbreaks because they are generally considered to be unpredictable. Objective: We sought to develop a mathematical model for predicting risks of oyster norovirus outbreaks using environmental predictors. Methods: We developed a novel probability-based Artificial Neural Network model, called NORF model, using 21 years of environmental and norovirus outbreak data collected from Louisiana oyster harvesting areas along the Gulf of Mexico coast, USA. The NORF model involves six input variables that were selected through stepwise regression analysis and sensitivity analysis. Results: We found that the model-based probability of norovirus outbreaks was most sensitive to gage height (the depth of water in an oyster bed) and water temperature, followed by wind, rainfall, and salinity, respectively. The NORF model predicted all historical oyster norovirus outbreaks from 1994 through 2014. Specifically, norovirus outbreaks occurred when the NORF model probability estimate was > 0.6, whereas no outbreaks occurred when the estimated probability was < 0.5. Outbreaks may also occur when the estimated probability is 0.5–0.6. Conclusions: Our findings require further confirmation, but they suggest that oyster norovirus outbreaks may be predictable using the NORF model. The ability to predict oyster norovirus outbreaks at their onset may make it possible to prevent or at least reduce the risk of norovirus outbreaks by closing potentially affected oyster beds. Citation: Wang J, Deng Z. 2016. Modeling and prediction of oyster norovirus outbreaks along Gulf of Mexico coast. Environ Health Perspect 124:627–633; http://dx.doi.org/10.1289/ehp.1509764 PMID:26528621

  7. Effects of age and composition of field-produced biofilms on oyster larval setting.

    PubMed

    Campbell, Alaina H; Meritt, Donald W; Franklin, Rima B; Boone, Edward L; Nicely, Carol T; Brown, Bonnie L

    2011-03-01

    Lack of success in restoring the native Eastern oyster, Crassostrea virginica, to Chesapeake Bay has been linked to the low occurrence of oyster larval setting in tributaries to the Bay. Among the many potential factors that could affect efforts to produce oysters through aquaculture or supplementation of shell beds is substratum condition. The present study examined larval setting on field-produced biofilms from Little Wicomico River (Virginia, USA) to assess whether bacterial community structure (examined by terminal restriction fragment length polymorphism, T-RFLP) or other characteristics of contemporary biofilms in this tributary (biofilm age and mass, algal abundance, and percentage organic matter) inhibited setting of larval oysters. The structure of the natural and heterogenous bacterial community in the biofilms and the success of oyster set were correlated, suggesting that specific microbial species may play a role in oyster setting. Larval set increased with biofilm age and mass, suggesting that established field-produced biofilms have no inhibitory effect. In contrast, the percentage of organic matter was negatively correlated with oyster set, whereas chlorophyll a concentration had no observed effect. The study expands prior knowledge by providing a more realistic timeframe for biofilm development (weeks as opposed to days), recounting effects of biofilms that are more representative of the natural dynamic and disturbance processes that would be expected to occur on submerged structures, and by incorporating seasonal and spatial variation. An important negative effect observed during the study period was heavy predation by Stylochus ellipticus on newly set oysters. Overall, the results of this study, which is the first assessment of the effects of biofilms produced naturally within a Chesapeake Bay tributary, suggest that the absence of large numbers of oysters in Little Wicomico River is not related to microbes or other specific characteristics of

  8. Mortalities of Eastern and Pacific oyster Larvae caused by the pathogens Vibrio coralliilyticus and Vibrio tubiashii.

    PubMed

    Richards, Gary P; Watson, Michael A; Needleman, David S; Church, Karlee M; Häse, Claudia C

    2015-01-01

    Vibrio tubiashii is reported to be a bacterial pathogen of larval Eastern oysters (Crassostrea virginica) and Pacific oysters (Crassostrea gigas) and has been associated with major hatchery crashes, causing shortages in seed oysters for commercial shellfish producers. Another bacterium, Vibrio coralliilyticus, a well-known coral pathogen, has recently been shown to elicit mortality in fish and shellfish. Several strains of V. coralliilyticus, such as ATCC 19105 and Pacific isolates RE22 and RE98, were misidentified as V. tubiashii until recently. We compared the mortalities caused by two V. tubiashii and four V. coralliilyticus strains in Eastern and Pacific oyster larvae. The 50% lethal dose (LD50) of V. coralliilyticus in Eastern oysters (defined here as the dose required to kill 50% of the population in 6 days) ranged from 1.1 × 10(4) to 3.0 × 10(4) CFU/ml seawater; strains RE98 and RE22 were the most virulent. This study shows that V. coralliilyticus causes mortality in Eastern oyster larvae. Results for Pacific oysters were similar, with LD50s between 1.2 × 10(4) and 4.0 × 10(4) CFU/ml. Vibrio tubiashii ATCC 19106 and ATCC 19109 were highly infectious toward Eastern oyster larvae but were essentially nonpathogenic toward healthy Pacific oyster larvae at dosages of ≥1.1 × 10(4) CFU/ml. These data, coupled with the fact that several isolates originally thought to be V. tubiashii are actually V. coralliilyticus, suggest that V. coralliilyticus has been a more significant pathogen for larval bivalve shellfish than V. tubiashii, particularly on the U.S. West Coast, contributing to substantial hatchery-associated morbidity and mortality in recent years.

  9. Oyster resource zones of the Barataria and Terrebonne estuaries of Louisiana

    USGS Publications Warehouse

    Melancon, E.; Soniat, T.; Cheramie, V.; Dugas, R.; Barras, J.; Lagarde, M.

    1998-01-01

    A 1:100,000 scale map delineating the subtidal oyster resource zones within the Barataria and Terrebonne estuaries was developed. Strategies to accomplish the task included interviews with Louisiana oystermen and state biologists to develop a draft map, field sampling to document oyster (Crassostrea virginica), Dermo (Perkinsus marinus), and oyster drill (Stramonita haemastoma) abundances, use of historical salinity data to aid in map verification, and public meetings to allow comment on a draft before final map preparation. Four oyster resource zones were delineated on the final map: a dry zone where subtidal oysters may be found when salinities increase, a wet zone where subtidal oysters may be found when salinities are suppressed, a wet-dry zone where subtidal oysters may be consistently found due to favorable salinities, and a high-salinity zone where natural oyster populations are predominantly found in intertidal and shallow waters. The dry zone is largely coincident with the brackish-marsh habitat, with some intermediate-type marsh. The wet-dry zone is found at the interface of the brackish and saline marshes, but extends further seaward than up-estuary. The wet zone and the high salinity zones are areas of mostly open water fringed by salt marshes. The dry zone encompasses 91,775 hectares, of which 48,788 hectares are water (53%). The wet zone encompasses 83,525 hectares, of which 66,958 hectares are water (80%). The wet-dry zone encompasses 171,893 hectares, of which 104,733 hectares are water (61%). The high salinity zone encompasses 125,705 hectares, of which 113,369 hectares are water (90%). There is a clear trend of increasing water habitat in the four zones over the past 30 years, and oysters are now cultivated on bottoms that were once marsh. The map should be useful in managing the effects upon oysters of freshwater diversions into the estuaries. It provides a pre-diversion record of the location of oyster resource zones and should prove helpful in

  10. [History of oyster as drug from the origin to the 21st century].

    PubMed

    Bonnemain, Bruno

    2015-06-01

    Since Antiquity, oyster is a subject of interest and medical use, as indicated by Oribiase and Galien. From the 17th century, this unique drug was proposed by physicians for various diseases, and more often for (la rage). One could think that that drug disappeared at the 20th and 21st centuries. But we can observe that it was still recommended by several authors as drug. Still today, companies offer oyster under various forms for allopathic and homeopathic treatments, as well as for food supplement. Research are ongoing to discover active substances within oyster and their potential medical interests.

  11. Differential proteomic responses of selectively bred and wild-type Sydney rock oyster populations exposed to elevated CO2.

    PubMed

    Thompson, E L; O'Connor, W; Parker, L; Ross, P; Raftos, D A

    2015-03-01

    Previous work suggests that larvae from Sydney rock oysters that have been selectively bred for fast growth and disease resistance are more resilient to the impacts of ocean acidification than nonselected, wild-type oysters. In this study, we used proteomics to investigate the molecular differences between oyster populations in adult Sydney rock oysters and to identify whether these form the basis for observations seen in larvae. Adult oysters from a selective breeding line (B2) and nonselected wild types (WT) were exposed for 4 weeks to elevated pCO2 (856 μatm) before their proteomes were compared to those of oysters held under ambient conditions (375 μatm pCO2 ). Exposure to elevated pCO2 resulted in substantial changes in the proteomes of oysters from both the selectively bred and wild-type populations. When biological functions were assigned, these differential proteins fell into five broad, potentially interrelated categories of subcellular functions, in both oyster populations. These functional categories were energy production, cellular stress responses, the cytoskeleton, protein synthesis and cell signalling. In the wild-type population, proteins were predominantly upregulated. However, unexpectedly, these cellular systems were downregulated in the selectively bred oyster population, indicating cellular dysfunction. We argue that this reflects a trade-off, whereby an adaptive capacity for enhanced mitochondrial energy production in the selectively bred population may help to protect larvae from the effects of elevated CO2 , whilst being deleterious to adult oysters.

  12. Cryptosporidium and Giardia in commercial and non-commercial oysters (Crassostrea gigas) and water from the Oosterschelde, The Netherlands.

    PubMed

    Schets, Franciska M; van den Berg, Harold H J L; Engels, George B; Lodder, Willemijn J; de Roda Husman, Ana Maria

    2007-01-25

    The intestinal parasites Cryptosporidium and Giardia cause gastro-enteritis in humans and can be transmitted via contaminated water. Oysters are filter feeders that have been demonstrated to accumulate pathogens such as Salmonella, Vibrio, norovirus and Cryptosporidium from contaminated water and cause foodborne infections. Oysters are economically important shellfish that are generally consumed raw. Commercial and non-commercial oysters (Crassostrea gigas) and oyster culture water from the Oosterschelde, The Netherlands, were examined for the presence of Cryptosporidium oocysts and Giardia cysts. Nine of 133 (6.7%) oysters from two non-commercial harvesting sites contained Cryptosporidium, Giardia or both. Six of 46 (13.0%) commercial oysters harboured Cryptosporidium or Giardia in their intestines. Data on the viability of (oo)cysts recovered from Oosterschelde oysters were not obtained, however viable (oo)cysts were detected in surface waters that enter the Oosterschelde oyster harvesting areas. The detection of Cryptosporidium and Giardia in oysters destined for human consumption has implications for public health only when human pathogenic (oo)cysts that have preserved infectivity during their stay in a marine environment are present. Our data suggest that consumption of raw oysters from the Oosterschelde may occasionally lead to cases of gastro-intestinal illness.

  13. Heavy metals in oyster tissue around three coastal marinas

    SciTech Connect

    Marcus, J.M.; Thompson, A.M.

    1986-04-01

    The past decade has presented an unprecedented period of growth and development along the coastline of South Carolina. The majority of this development has been to serve the recreation and tourism industry and, as such, has included the construction of numerous recreational marinas in the coastal waters of the State. Various plans have been presented for the siting of marinas in pristine estuarine waters. This has raised much concern due to the possible impacts of such development on the plentiful oyster resource found in those waters. Marinas present the potential for the introduction of pollutants such as heavy metals into the surrounding waters. This investigation was conducted by the South Carolina Department of Health and Environmental Control (SCDHEC) during 1983, and yielded a multifaceted data base composed of physiocochemical and bacteriological analyses from water, chemical analyses from sediment and chemical/bacteriological physiological analyses from the American oyster, Crassostrea virginica (Gmelin). C. virginica was chosen as the organism of interest due to its wide distribution in the estuaries of South Carolina, its importance as an economic and recreational resource and its suitability as a sentinel organism for monitoring coastal pollution.

  14. Ingestion of Nanoplastics and Microplastics by Pacific Oyster Larvae.

    PubMed

    Cole, Matthew; Galloway, Tamara S

    2015-12-15

    Plastic debris is a prolific contaminant effecting freshwater and marine ecosystems across the globe. Of growing environmental concern are "microplastics"and "nanoplastics" encompassing tiny particles of plastic derived from manufacturing and macroplastic fragmentation. Pelagic zooplankton are susceptible to consuming microplastics, however the threat posed to larvae of commercially important bivalves is currently unknown. We exposed Pacific oyster (Crassostrea gigas) larvae (3-24 d.p.f.) to polystyrene particles spanning 70 nm-20 μm in size, including plastics with differing surface properties, and tested the impact of microplastics on larval feeding and growth. The frequency and magnitude of plastic ingestion over 24 h varied by larval age and size of polystyrene particle (ANOVA, P < 0.01), and surface properties of the plastic, with aminated particles ingested and retained more frequently (ANOVA, P < 0.01). A strong, significant correlation between propensity for plastic consumption and plastic load per organism was identified (Spearmans, r = 0.95, P < 0.01). Exposure to 1 and 10 μm PS for up to 8 days had no significant effect on C. gigas feeding or growth at <100 microplastics mL(-1). In conclusion, whil micro- and nanoplastics were readily ingested by oyster larvae, exposure to plastic concentrations exceeding those observed in the marine environment resulted in no measurable effects on the development or feeding capacity of the larvae over the duration of the study.

  15. Polynuclear aromatic hydrocarbons in oyster tissue around three coastal marinas

    SciTech Connect

    Marcus, J.M.; Stokes, T.P.

    1985-12-01

    Marinas present the potential for introduction of various pollutants into the surrounding waters such as coliform bacteria, primary pathogens, heavy metals, and petroleum hydrocarbons. Little data have been presented specifically addressing the effects of recreational marinas on petroleum hydrocarbon levels or, for that matter, other constituent levels in oysters near those marinas. In order to obtain such data, a comprehensive assessment of water and oyster quality around three coastal marinas was conducted by the South Carolina Department of Health and Environmental control (SCDHEC) during 1983. Polynuclear aromatic hydrocarbons (PAH) were selected as the petroleum hydrocarbon fraction of interest since they are mainly of pyrogenic origin; have been shown to be the most toxic/carcinogenic fraction of oil; have been shown to affect the respiration and heart rates of mussels; and have been shown to be linked to neoplasia in clams and proliferative disorders in mussels. C. virginica was chosen as the mollusc of interest because of its widespread distribution in the estuaries of South Carolina, its importance as an economic and recreational resource, and its suitability as a sentinel organism for monitoring coastal pollution.

  16. Richness and distribution of tropical oyster parasites in two oceans.

    PubMed

    Pagenkopp Lohan, Katrina M; Hill-Spanik, Kristina M; Torchin, Mark E; Aguirre-Macedo, Leopoldina; Fleischer, Robert C; Ruiz, Gregory M

    2016-08-01

    Parasites can exert strong effects on population to ecosystem level processes, but data on parasites are limited for many global regions, especially tropical marine systems. Characterizing parasite diversity and distributions are the first steps towards understanding the potential impacts of parasites. The Panama Canal serves as an interesting location to examine tropical parasite diversity and distribution, as it is a conduit between two oceans and a hub for international trade. We examined metazoan and protistan parasites associated with ten oyster species collected from both Panamanian coasts, including the Panama Canal and Bocas del Toro. We found multiple metazoan taxa (pea crabs, Stylochus spp., Urastoma cyrinae). Our molecular screening for protistan parasites detected four species of Perkinsus (Perkinsus marinus, Perkinsus chesapeaki, Perkinsus olseni, Perkinsus beihaiensis) and several haplosporidians, including two genera (Minchinia, Haplosporidium). Species richness was higher for the protistan parasites than for the metazoans, with haplosporidian richness being higher than Perkinsus richness. Perkinsus species were the most frequently detected and most geographically widespread among parasite groups. Parasite richness and overlap differed between regions, locations and oyster hosts. These results have important implications for tropical parasite richness and the dispersal of parasites due to shipping associated with the Panama Canal.

  17. Metal concentration in oysters from the southern African coast

    SciTech Connect

    Watling, H.R.; Watling, R.J.

    1982-04-01

    The survey presented of metal concentrations in Crassostrea margaritacea growing at 25 sites along a 500 km stretch of the South African coast was undertaken to provide data for the national marine pollution monitoring program and to supplement data from sediment and water sampling surveys of the estuaries in the region. Concentrations of Zn, Cd, Cu, Pb, Fe, Mn, Ni, Co, and Cr in C. margaritacea were determined, and the data indicated that some contamination of Victoria Bay environment had occurred; oysters from this site had accumulated Zn, Pb, Ni, Cr, and possibly, Co. Oysters growing at the mouth of the Papenkuils River and the Swartkops River were also found to be contaminated with Zn, Pb, Cu, and Cr, to a lesser extent. C. margaritacea growing at the mouth of the Great Fish River unexpectedly had elevated Cu, Pb, and Cr concentrations. Because there are no urban or industrial developments along the river, it was likely that these elements are derived from leaching of mineralized sequences in the catchment, and a geochemical survey was recommended to ascertain the source of the metals. (JMT)

  18. Anatomical distribution of sterols in oysters (Crassostrea gigas).

    PubMed

    Gordon, D T; Collins, N

    1982-11-01

    Oysters (Crassostrea gigas) contain at least 8 predominant sterols as determined by gas liquid chromatography and a modified Liebermann-Burchard reaction. These sterols and the average amount found in mg/100 are: C26-sterol (22-trans-24-norcholesta-5, 22-diene-3 beta-ol), 19.1; 22-dehydrocholesterol, 15.1; cholesterol, 46.8; brassicasterol, 27.2; delta 5,7-sterols (i.e., 7-dehydrocholesterol) 22.5; 24-methylenecholesterol 29.1; 24-ethylcholesta-5,22-diene-3 beta-ol, 1.2; and 24-ethylcholesta-5-en-3 beta-ol, 12.7. The distribution of these sterols appears uniform (r2 = 0.938) between 5 major organs of the oyster. The percent body mass vs percent total sterols in these 5 organs are: mantle 44.1--41.4; visceral mass 30.3--36.7; gills 13.2--11.7; adductor muscle 8.3--3.7; and labial palps 4.2--6.5. The possible sources of these sterols are discussed.

  19. The role of oyster restoration and aquaculture in nitrogen removal within a Rhode Island estuary

    EPA Science Inventory

    Coastal systems are increasingly impacted by over-enrichment of nutrients, which has cascading effects for ecosystem functioning. Oyster aquaculture and restoration are hypothesized to mitigate excessive nitrogen (N) loads via assimilation, burial, or benthic denitrification. Stu...

  20. The summer uptake and release of nitrogen by an intertidal oyster reef

    NASA Astrophysics Data System (ADS)

    Dame, R. F.; Wolaver, T. G.; Libes, S. M.

    It has long been speculated that oyster reefs process estuarine nutrients, but direct observation of this has been difficult. With a plastic tunnel (BEST - Benthic Ecosystem Tunnel), input/output concentrations of nitrogen and water velocities over an oyster reef were measured for 7 tidal cycles during summer conditions. Ammonia was always released from the oyster reef and average rates varied from 2825 to 15 304 μmol·m -2·h -1. Ammonia release was usually higher on the ebb tide than the flood tide. It is speculated that nitrogen uptake and release may be a function of not only feeding and digestive behaviour, but also of water velocity. The magnitude of ammonia release is much higher than any previous observations on natural benthic systems, suggesting that oyster reefs may be important components in nitrogen cycling in estuaries.

  1. Use of extracts from oyster shell and soil for cultivation of Spirulina maxima.

    PubMed

    Jung, Joo-Young; Kim, Sunmin; Lee, Hansol; Kim, Kyochan; Kim, Woong; Park, Min S; Kwon, Jong-Hee; Yang, Ji-Won

    2014-12-01

    Calcium ion and trace metals play important roles in various metabolisms of photosynthetic organisms. In this study, simple methods were developed to extract calcium ion and micronutrients from oyster shell and common soil, and the prepared extracts were tested as a replacement of the corresponding chemicals that are essential for growth of microalgae. The oyster shell and soil were treated with 0.1 M sodium hydroxide or with 10 % hydrogen peroxide, respectively. The potential application of these natural sources to cultivation was investigated with Spirulina maxima. When compared to standard Zarrouk medium, the Spirulina maxima cultivated in a modified Zarrouk media with elements from oyster shell and soil extract exhibited increases in biomass, chlorophyll, and phycocyanin by 17, 16, and 64 %, respectively. These results indicate that the extracts of oyster shell and soil provide sufficient amounts of calcium and trace metals for successful cultivation of Spirulina maxima.

  2. Fresh Water Inflow and Oyster Productivity in Apalachicola Bay, FL (USA)

    EPA Science Inventory

    Apalachicola Bay lies at the mouth of the Apalachicola River, where seasonally variable freshwater inflows and shifting winds support an unusually productive and commercially important oyster fishery. While there is concern that upstream water withdrawals may impact the fishery,...

  3. Spatial distribution and biophysics chemistry characterization of Pearl Oyster farming in Semau Strait, East Nusa Tenggara

    NASA Astrophysics Data System (ADS)

    Yulia Wardani, Enggar; Wardiatno, Yusli; Bahri Agus, Syamsul

    2017-01-01

    Pearl oyster is one of marine organisms which has high of economic value. One of Indonesia region that potential for pearl oyster farming activity is Semau Strait-East Nusa Tenggara. The purpose of this study is mapping and characterize spatial distribution based on biophysics chemistry condition of pearl oyster farming. Mapping using Geographic Information System (GIS) tools, while grouping and characterize using hierarchical clustering and Mann-Whitney method. Grouping based on character similarity of biophysics chemistry divided the stations distribution into three groups: Group I is excellent group, Group II is good group and Group III is bad group for pearl oyster farming. Group I is excellent area because it has the highest values of dissolved oxygen, chlorophyll-a, and phytoplankton abundance. Group III is bad area because it temperature is high relatively.

  4. Effects of glutathione depletion on copper cytotoxicity in oysters (Crassostrea virginica).

    PubMed

    Conners; Ringwood

    2000-10-01

    Glutathione is a tripeptide that plays an important role in ameliorating metal toxicity. Depletion of glutathione has been associated with an increased risk of metal toxicity in mammals. An understanding of the toxicological significance of glutathione depletion in oysters would be of considerable importance given the widespread use of bivalves in biological monitoring. Laboratory studies were conducted by using an inhibitor of glutathione synthesis (buthionine sulfoximine) to investigate the effects of glutathione depletion on metallothionein expression, lysosomal membrane destabilization, and lipid peroxidation in Cu-exposed oysters. In oysters exposed to Cu (20 and 80 µg/l) and buthionine sulfoximine (20 mg/l), metallothionein induction was suppressed and cellular stress responses were frequently higher than those observed in oysters exposed singly to Cu. Together, these results suggest that environmental conditions that cause glutathione depletion may increase the potential for adverse effects to pollutants during in situ exposures.

  5. Elimination of laboratory-acquired cadmium by the oyster Crassostrea virginica in the natural environment

    SciTech Connect

    Mowdy, D.E.

    1981-03-01

    Many productive shellfish-growing areas along the coast of the United States are closed because of pollution from domestic and industrial wastes. Many estuarine areas that are closed to shellfish harvesting because of bacterial pollution contain productive shellfish beds. These shellfish can be used as commercial food products after they have been relayed to approved growing waters and allowed to eliminate the polluting organisms. Relaying is not presently applied to shellfish contaminated with toxic metals for several reasons: There are no standards to control metal pollution (other than mercury) in seafood; few public health problems in this country involve toxic levels of trace metals in oysters; and not enough information is available to indicate the feasibility of such a project. This study demonstrates the feasibility of relaying cadmium-contaminated oysters to observe cadmium elimination. Because oysters containing naturally acquired cadmium were not readily available, oysters containing laboratory-incurred cadmium were studied.

  6. INFLUENCE OF SEASONAL FACTORS ON OYSTER HEMOCYTE KILLING OF VIBRIO PARAHEMOLYTICUS

    EPA Science Inventory

    Seasonal variation of cellular defenses of oyster Crassostrea virginica against Vibrio parahaemolyticus were examined from June 1997 to December 1998 using a recently developed bactericidal assay that utilizes a tetrazolium dye. Mean hemocyte numbers, plasma lysozyme, and P. mari...

  7. EFFECTS OF FRESHWATER RELEASES AND SEASON ON OYSTERS (CRASSOSTREA VIRGINICA) IN CALOOSAHATCHEE ESTUARY, FLORIDA

    EPA Science Inventory

    The influence of freshwater releases and season on disease prevalence and intensity of Perkinsus marinus, condition index, gonadal condition, recruitment potential, and growth of oysters was examined monthly at five locations along the Caloosahatchee estuary, Florida. Temperature...

  8. WATER QUALITY AND OYSTER HEALTH (CRASSOSTREA VIRGINICA): AN INTEGRATED APPROACH TO DETERMINING HABITAT RESTORATION POTENTIAL

    EPA Science Inventory

    Volety, Aswani K., S. Gregory Tolley and James T. Winstead. 2001. Water Quality and Oyster Health (Crassostrea virginica): An Integrated Approach to Determining Habitat Restoration Potential (Abstract). Presented at the 5th International Conference on Shellfish Restoration, 18-21...

  9. A metabolomic investigation of the effects of metal pollution in oysters Crassostrea hongkongensis.

    PubMed

    Ji, Chenglong; Wang, Qing; Wu, Huifeng; Tan, Qiaoguo; Wang, Wen-Xiong

    2015-01-15

    Metal pollution has been of great concern in the estuaries in Southern China. In this study, metabolic differences between oysters Crassostrea hongkongensis from clean and metal-polluted sites were characterized using NMR-based metabolomics. We collected oyster samples from one clean (Jiuzhen) and two metal polluted sites (Baijiao and Fugong). The metal concentrations in oyster gills indicated that both the Baijiao and Fugong sites were severely polluted by several metals, including Cr, Ni, Cu, Zn, Ag, Cd and Pb. In particular, Cu and Zn were the major contaminants from the Baijiao and Fugong sites. Compared with those oysters from the clean site (JZ), metal pollution in BJ and FG induced disturbances in osmotic regulation and energy metabolism via different metabolic pathways, as indicated by different metabolic biomarkers. This study demonstrates that NMR-based metabolomics is a useful tool for characterizing metabolic responses induced by metal pollution.

  10. Detection of enteric viruses in oysters by using the polymerase chain reaction.

    PubMed Central

    Atmar, R L; Metcalf, T G; Neill, F H; Estes, M K

    1993-01-01

    A procedure for the detection of enteric viral nucleic acid in oysters by the polymerase chain reaction was developed. Known quantities of poliovirus type 1 were seeded into oysters. Virus was extracted and concentrated by using organic flocculation and polyethylene glycol precipitation. Inhibitors of reverse transcription-polymerase chain reaction were present in the oyster extracts, preventing amplification of target viral nucleic acid. The use of cetyltrimethylammonium bromide precipitation sufficiently removed inhibitors to allow detection of as few as 10 PFU of poliovirus. Norwalk virus also could be detected after being seeded into oysters. This methodology may be useful for the detection of these and other shellfish-borne viral pathogens. Images PMID:8382024

  11. THE EFFECT OF PCBS ON GLYCOGEN RESERVES IN THE EASTERN OYSTER CRASSOSTREA VIRGINICA. (R825349)

    EPA Science Inventory

    Recent declines in Chesapeake Bay oyster populations have been attributed to disease, and reduced water quality from pollution. The stress associated with pollutant exposure may reduce energy available for growth and reproduction. Polychlorinated biphenyls (PCBs) are lipophilic c...

  12. Impact of diuron on aneuploidy and hemocyte parameters in Pacific oyster, Crassostrea gigas.

    PubMed

    Bouilly, Karine; Bonnard, Marc; Gagnaire, Béatrice; Renault, Tristan; Lapègue, Sylvie

    2007-01-01

    Diuron is a substituted urea herbicide used for agricultural and nonagricultural weed control. Its widespread use and relatively slow breakdown led us to analyze its influence on aneuploidy level (lowered chromosome number in a percentage of somatic cells) and hemocyte parameters in Pacific oysters, Crassostrea gigas. Adult oysters were subjected to two diuron concentrations (300 ng L(-1) and 3 microg L(-1)) for 11 weeks. Significantly higher aneuploidy level was observed in diuron-treated oysters compared with the control. Furthermore, the observed impact on aneuploidy persisted to the next generation as offspring exhibited significantly higher aneuploidy levels when their parents had been exposed to diuron. Significant increases in hemocyte parameters (cell mortality, phagocytosis, granulocyte percentage, reactive oxygen species, and lysosome presence) of the adults were also observed after 4 weeks of diuron exposure. The effects observed on oyster aneuploidy level and hemocyte parameters could have serious environmental and practical consequences.

  13. Transesterification of soybean oil using combusted oyster shell waste as a catalyst.

    PubMed

    Nakatani, Nobutake; Takamori, Hitoshi; Takeda, Kazuhiko; Sakugawa, Hiroshi

    2009-02-01

    Transesterification of soybean oil catalyzed by combusted oyster shell, which is waste material from shellfish farms, was examined. Powdered oyster shell combusted at a temperature above 700 degrees C, at which point the calcium carbonate of oyster shell transformed to calcium oxide, acted as a catalyst in the transesterification of soybean oil. On the basis of factorial design, the reaction conditions of catalyst concentration and reaction time were optimized in terms of the fatty acid methyl ester concentration expressed as biodiesel purity. Under the optimized reaction conditions of a catalyst concentration and reaction time of 25wt.%. and 5h, respectively, the biodiesel yield, expressed relative to the amount of soybean oil poured into the reaction vial, was more than 70% with high biodiesel purity. These results indicate oyster shell waste combusted at high temperature can be reused in biodiesel production as a catalyst.

  14. The role of oyster restoration and aquaculture in nutrient cycling within a Rhode Island estuary

    EPA Science Inventory

    Coastal ecosystems are increasingly impacted by over-enrichment of nutrients, which has cascading effects for other organisms. Oyster aquaculture and restoration are hypothesized to mitigate excessive nitrogen (N) loads via benthic denitrification. However, this has not been exam...

  15. A metabolomic study on the biological effects of metal pollutions in oysters Crassostrea sikamea.

    PubMed

    Ji, Chenglong; Wang, Qing; Wu, Huifeng; Tan, Qiaoguo; Wang, Wen-Xiong

    2016-01-15

    Metal pollution has become a great threat to organisms in the estuaries in South China. In the present study, the oysters Crassostrea sikamea were collected from one clean (Jiuzhen) and five metal polluted sites (Baijiao, Fugong, Gongqian, Jinshan and Songyu). The tissue metal concentrations in oysters indicated that the five metal sites were polluted by several metals, including Cr, Ni, Co, Cu, Zn, Ag, Cd and Pb with different patterns. Especially, Cu and Zn were the major contaminants in Baijiao, Fugong and Jinshan sites. The metabolic responses in oysters C. sikamea indicated that the metal pollutions in BJ, FG, JS and SY sites induced disturbances in osmotic regulation and energy metabolism via different metabolic pathways. However, the metal pollution in GQ site mainly influenced the osmotic regulation in the oysters C. sikamea. This study demonstrates that NMR-based metabolomics is useful to characterize metabolic responses induced by metal pollution.

  16. EFFECTS OF SEASONAL AND WATER QUALITY PARAMETERS ON OYSTERS (CRASSOSTREA VIRGINICA) AND ASSOCIATED FISH POPULATIONS.

    EPA Science Inventory

    Influence of water quality and seasonal changes on disease prevalence and intensity of Perkinsus marinus, gonadal condition, recruitment potential, growth of caged juvenile oysters, and habitat suitability of reefs for fishes and macrobenthic invertebrates were measured in Callos...

  17. IN VITRO KILLING OF PERKINSUS MARINUS BY HEMOCYTES OF OYSTERS CRASSOSTREA VIRGINICA

    EPA Science Inventory

    A colorimetric microbicidal assay was adapted, optimized and applied in experiments to characterize the in vitro capacity of eastern oyster (Crassostrea virginica) hemocytes to kill cultured isolates of Perkinsus marinus, a protozoan parasite causing a highly destructive disease...

  18. Rapid detection of toxic metals in non-crushed oyster shells by portable X-ray fluorescence spectrometry.

    PubMed

    Chou, Ju; Clement, Garret; Bursavich, Bradley; Elbers, Don; Cao, Baobao; Zhou, Weilie

    2010-06-01

    The aim of this study was the multi-elemental detection of toxic metals such as lead (Pb) in non-crushed oyster shells by using a portable X-ray fluorescence (XRF) spectrometer. A rapid, simultaneous multi-element analytical methodology for non-crushed oyster shells has been developed using a portable XRF which provides a quick, quantitative, non-destructive, and cost-effective mean for assessment of oyster shell contamination from Pb. Pb contamination in oyster shells was further confirmed by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The results indicated that Pb is distributed in-homogeneously in contaminated shells. Oyster shells have a lamellar structure that could contribute to the high accumulation of Pb on oyster shells.

  19. Application of ICP-AES with microwave digestion to detect trace elements in oysters from Jiaozhou Bay, China

    NASA Astrophysics Data System (ADS)

    Zheng, Kang; Yan, Cuiwei

    2011-09-01

    Using ICP-AES with microwave digestion, we determined the concentrations of 16 trace elements in oysters from six sampling points in Jiaozhou Bay. The distributions of the wholesome elements Zn, Fe and Mn, and heavy metals such as As, Cd, Hg and Pb were studied. The oysters collected are all rich in the wholesome trace elements, and the oysters from Licun River have the highest concentrations of the three wholesome trace elements. The concentrations of heavy metals in oysters from Licun River are the highest and those from Hongdao are the lowest. Compared with the domestic and foreign sea-areas, the heavy metal contents in the oysters from Jiaozhou Bay are less in amount than those from some developed countries, and more than those in Southeast China. This implies that the Jiaozhou Bay's oysters have been polluted by the environment to some extent.

  20. Changes in microbial flora of Pacific oysters (Crassostrea gigas) during refrigerated storage and its shelf-life extension by chitosan.

    PubMed

    Cao, Rong; Xue, Chang-Hu; Liu, Qi

    2009-05-31

    Changes in microbial flora of Pacific oysters (Crassostrea gigas) during storage at 5+/-1 degrees C were analyzed and the antimicrobial activity of chitosan was studied to identify its potential in shelf-life extension. The dominant microorganisms were found to be Pseudomonas (22%) and Vibrionaceae (20%) in raw oysters. During storage, proportion of Pseudomonas increased significantly and reached 73% at the end of storage, while Vibrionaceae preserved a level of approximate 20%. Wide-spectrum antibacterial property of chitosan against the bacteria isolated from oysters was discovered, and chitosan concentration of 5.0 g/L was eventually determined for application in oyster preservation. Based on microbiological analysis, biochemical indices determination and sensory evaluation, shelf-life of oysters stored at 5+/-1 degrees C was determined. Data showed that chitosan treatment extended the shelf-life of oysters from 8-9 days to 14-15 days.

  1. Optimal Site Characterization and Selection Criteria for Oyster Restoration using Multicolinear Factorial Water Quality Approach

    NASA Astrophysics Data System (ADS)

    Yoon, J.

    2015-12-01

    Elevated levels of nutrient loadings have enriched the Chesapeake Bay estuaries and coastal waters via point and nonpoint sources and the atmosphere. Restoring oyster beds is considered a Best Management Practice (BMP) to improve the water quality as well as provide physical aquatic habitat and a healthier estuarine system. Efforts include declaring sanctuaries for brood-stocks, supplementing hard substrate on the bottom and aiding natural populations with the addition of hatchery-reared and disease-resistant stocks. An economic assessment suggests that restoring the ecological functions will improve water quality, stabilize shorelines, and establish a habitat for breeding grounds that outweighs the value of harvestable oyster production. Parametric factorial models were developed to investigate multicolinearities among in situ water quality and oyster restoration activities to evaluate posterior success rates upon multiple substrates, and physical, chemical, hydrological and biological site characteristics to systematically identify significant factors. Findings were then further utilized to identify the optimal sites for successful oyster restoration augmentable with Total Maximum Daily Loads (TMDLs) and BMPs. Factorial models evaluate the relationship among the dependent variable, oyster biomass, and treatments of temperature, salinity, total suspended solids, E. coli/Enterococci counts, depth, dissolved oxygen, chlorophyll a, nitrogen and phosphorus, and blocks consist of alternative substrates (oyster shells versus riprap, granite, cement, cinder blocks, limestone marl or combinations). Factorial model results were then compared to identify which combination of variables produces the highest posterior biomass of oysters. Developed Factorial model can facilitate maximizing the likelihood of successful oyster reef restoration in an effort to establish a healthier ecosystem and to improve overall estuarine water quality in the Chesapeake Bay estuaries.

  2. Modeling and Mapping Oyster Norovirus Outbreak Risks in Gulf of Mexico Using NASA MODIS Aqua Data

    NASA Astrophysics Data System (ADS)

    Deng, Z.; Wang, J.

    2015-12-01

    Norovirus is a highly infectious virus and the leading cause of foodborne disease outbreaks such as oyster norovirus outbreaks. Currently, there is no vaccine to prevent norovirus infection and no drug to treat it. This paper presents an integrated modeling and mapping framework for predicting the risk of norovirus outbreaks in oyster harvesting waters in the Northern Gulf of Mexico coast. The framework involves (1) the construction of three novel remote sensing algorithms for the retrieval of sea surface salinity, sea surface temperature, and gage height (tide level) using NASA MODIS Aqua data; (2) the development of probability-based Artificial Neural Network (ANN) model for the prediction of oyster norovirus outbreak risk, and (3) the application of the Local Indicators of Spatial Association (LISA) for mapping norovirus outbreak risks in oyster harvesting areas in the Northern Gulf of Mexico using the remotely sensed NASA data, retrieved data from the three remote sensing algorithms, and the ANN model predictions. The three remote sensing algorithms are able to correctly retrieve 94.1% of sea surface salinity, 94.0% of sea surface temperature, and 77.8% of gage height observed along the US coast, including the Pacific coast, the Gulf of Mexico coast, and the Atlantic coast. The gage height, temperature, and salinity are the three most important explanatory variables of the ANN model in terms of spatially distributed input variables. The ANN model is capable of hindcasting/predicting all oyster norovirus outbreaks occurred in oyster growing areas along the Gulf of Mexico coast where environmental data are available. The integrated modeling and mapping framework makes it possible to map daily risks of norovirus outbreaks in all oyster harvesting waters and particularly the oyster growing areas where no in-situ environmental data are available, greatly improving the safety of seafood and reducing outbreaks of foodborne disease.

  3. A hemocyte gene expression signature correlated with predictive capacity of oysters to survive Vibrio infections

    PubMed Central

    2012-01-01

    Background 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 susceptibility to infections is thus a major goal for understanding field mortality events. In this context, we used high-throughput genomic approaches to identify genetic traits that may characterize inherent survival capacities in C. gigas. Results Using digital gene expression (DGE), we analyzed the transcriptomes of hemocytes (immunocompetent cells) of oysters able or not able to survive infections by Vibrio species shown to be involved in summer mortalities. Hemocytes were nonlethally collected from oysters before Vibrio experimental infection, and two DGE libraries were generated from individuals that survived or did not survive. Exploration of DGE data and microfluidic qPCR analyses at individual level showed an extraordinary polymorphism in gene expressions, but also a set of hemocyte-expressed genes whose basal mRNA levels discriminate oyster capacity to survive infections by the pathogenic V. splendidus LGP32. Finally, we identified a signature of 14 genes that predicted oyster survival capacity. Their expressions are likely driven by distinct transcriptional regulation processes associated or not associated to gene copy number variation (CNV). Conclusions We provide here for the first time in oyster a gene expression survival signature that represents a useful tool for understanding mortality events and for assessing genetic traits of interest for disease resistance selection programs. PMID:22708697

  4. Multiple clusters of norovirus among shellfish consumers linked to symptomatic oyster harvesters.

    PubMed

    McIntyre, Lorraine; Galanis, Eleni; Mattison, Kirsten; Mykytczuk, Oksana; Buenaventura, Enrico; Wong, Julie; Prystajecky, Natalie; Ritson, Mark; Stone, Jason; Moreau, Dan; Youssef, André

    2012-09-01

    We describe the investigation of a norovirus outbreak associated with raw oyster consumption affecting 36 people in British Columbia, Canada, in 2010. Several genotypes were found in oysters, including an exact sequence match to clinical samples in regions B and C of the norovirus genome (genogroup I genotype 4). Traceback implicated a single remotely located harvest site probably contaminated by ill shellfish workers during harvesting activities. This outbreak resulted in three recalls, one public advisory, and closure of the harvest site.

  5. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest), Pacific Oyster

    DTIC Science & Technology

    1988-09-01

    Loosanoff ( 965) de- broad, but only areas with suitable tails the various diseeses :ommon to habitat sustain populations of oy- juvenile oysters. sters...levels (Perdue Predators et al. 1981). Glude (1975) noted that this condition in the oysters was ac- Crabs and starfish can be serious companied by... crab Cancer lated summer mortality in the labora- maqister, the rock crab C. productus, tory and suggested that a Vibrio and the graceful crab C

  6. Seasonal tracking of histo-blood group antigen expression and norovirus binding in oyster gastrointestinal cells.

    PubMed

    Tian, Peng; Engelbrektson, Anna L; Mandrell, Robert E

    2008-08-01

    Noroviruses (NORs) are the most common cause of viral gastroenteritis outbreaks. Outbreaks are often associated with the consumption of contaminated oysters and generally occur between the months of November and March, when oysters produce the highest levels of glycogen. Oyster glycogen has been proposed as playing a role in NOR accumulation. Recent research indicates that histo-blood group antigens (HBGAs) function as viral receptors on human gastrointestinal cells. In this study, oyster glycogen was tested to determine whether it contains HBGA-like molecules and whether it plays a role in NOR binding. The correlation between the amount of HBGA expression and NOR binding also was measured. We also tested whether seasonal changes affected HBGA expression and binding of recombinant NORs. The results indicate that recombinant NOR binding is highly correlated with HBGA expression in Virginica (Crassostrea virginica), Pacific (Crassostrea gigas), and Kumamato (Crassostrea sikamea) oysters, but the association does not have a seasonal pattern. No obvious trend in either HBGA expression or recombinant NOR binding by month was noted. A significant increase in recombinant NOR binding was observed in Virginica and Pacific oysters in a season not generally associated with NOR gastroenteritis outbreaks. A significant increase in HBGA expression also was observed for Pacific and Virginica oysters in the same season. Paradoxically, HBGA expression and NOR binding both were higher in oysters produced in the non-NOR gastroenteritis season (April through October) than in those produced in the NOR gastroenteritis season (November through March), suggesting that seasonal NOR gastroenteritis outbreaks are not associated with high levels of HBGA expression or NOR binding.

  7. Using oysters as anthropogenic indicators to evaluate the occurrence of the wastewater contamination of the estuaries

    NASA Astrophysics Data System (ADS)

    Ding, Wang-Hsien

    2015-04-01

    The oyster (Crossostrea gigas) is an important aquacultural species in Taiwan. With an area of over 85% of the total inshore aquacultural field, its production, measured by quantity or economic value, ranks above all other aquacultural products in Taiwan. Since oyster's habitat is on shelves near the coast, the samples from a particular "oyster cultural site" can be applied to evaluate the pollution of a segment of the coastal water. Deficient wastewater treatment has caused untreated wastewaters to have flown in rivers into oyster cultural areas in estuaries as well as shallow coastal water. Therefore, the concentration of pollutants in the oysters can be used as anthropogenic indicators to evaluate the occurrence of the for wastewater contamination of the coastal water. In this study, two groups of anthropogenic organic compounds, chlorinated flame retardant (i.e., Dechlorane Plus) and benzophenone-type UV absorbing substances (i.e., 2-hydroxy-4-methoxybenzophenone), were determined in oyster samples as wastewater contamination pollutants. The method involves the use of matrix solid-phase dispersion prior to their determination by gas chromatography mass spectrometry. The results show that these two groups of compounds are ubiquitous in oysters with the concentrations of chlorinated flame retardant and benzophenone-type UV absorbing substances ranging from 0.3 to 3.6 ng/g and from 120 to 910 ng/g (lipid weight), respectively. Oysters are useful anthropogenic indicators of organic pollutants in Taiwan's marine environment. The ubiquity of these pollutants in Taiwan's coastal environment supports the need for greater awareness of bioaccumulation processes.

  8. Temporal variation in development of ecosystem services from oyster reef restoration

    USGS Publications Warehouse

    LaPeyre, Megan K.; Humphries, Austin T.; Casas, Sandra M.; La Peyre, Jerome F.

    2014-01-01

    Restoration ecology relies heavily on ecosystem development theories that generally assume development of fully functioning natural systems over time, but often fail to identify the time-frame required for provision of desired functions, or acknowledge different pathways of functional development. In estuaries, a decline of overall habitat quality and functioning has led to significant efforts to restore critical ecosystem services, recently through the creation and restoration of oyster reefs. Oyster reef restoration generally occurs with goals of (1) increasing water quality via filtration through sustainable oyster recruitment, (2) stabilizing shorelines, and (3) creating and enhancing critical estuarine habitat for fish and invertebrates. We restored over 260 m2 of oyster reef habitat in coastal Louisiana and followed the development and provision of these ecosystem services from 2009 through 2012. Oysters recruited to reefs immediately, with densities of oysters greater than 75 mm exceeding 80 ind m−2 after 3 years, and provision of filtration rates of 1002 ± 187 L h−1 m−2; shoreline stabilization effects of the created reefs were minimal over the three years of monitoring, with some evidence of positive shoreline stabilization during higher wind/energy events only; increased nekton abundance of resident, but not larger transient fish was immediately measurable at the reefs, however, this failed to increase through time. Our results provide critical insights into the development trajectories of ecosystem services provided by restored oyster reefs, as well as the mechanisms mediating these changes. This is critical both ecologically to understand how and where a reef thrives, and for policy and management to guide decision-making related to oyster reef restoration and the crediting and accounting of ecosystem services.

  9. Connectivity Among Three Restored Crassostrea Virginica Bars in the Severn River Estuary: Implications for Oyster Recovery Efforts

    DTIC Science & Technology

    2008-06-30

    planted in 2002) through time. The larger size classes represented by CC 10-07 may indicate that the part of the reef containing oysters grown in...Connectivity among three restored Crassostrea virginica bars in the Severn River Estuary; Implications for oyster recovery efforts...restored Crassostrea virginica bars in the Severn River Estuary: Implications for oyster recovery efforts 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  10. Geohistorical records indicate no impact of the Deepwater Horizon oil spill on oyster body size

    PubMed Central

    Durham, Stephen R.

    2016-01-01

    Documentation of the near- and long-term effects of the Deepwater Horizon (DWH) oil spill, one of the largest environmental disasters in US history, is still ongoing. We used a novel before-after-control-impact analysis to test the hypothesis that average body size of intertidal populations of the eastern oyster (Crassostrea virginica) inhabiting impacted areas in Louisiana decreased due to increased stress/mortality related to the oil spill. Time-averaged death assemblages of oysters were used to establish a pre-spill baseline of body-size structure for four impacted and four control locations along a 350 km stretch of Louisiana's coastline. Post-spill body sizes were then measured from live oysters at each site in order to evaluate the differences in body size between oiled (i.e. impact) and unoiled (i.e. control) locations before and after the spill. Our results indicate that average body size of oysters remained relatively unchanged after the oil spill. There were also no temporal patterns in temperature, salinity or disease prevalence that could have explained our results. Together, these findings suggest that oysters either recovered rapidly following the immediate impact of the DWH oil spill, or that its impact was not severe enough to influence short-term population dynamics of the oyster beds. PMID:28018663

  11. Reef-Specific Patterns of Gene Expression Plasticity in Eastern Oysters (Crassostrea virginica).

    PubMed

    Eierman, Laura E; Hare, Matthew P

    2016-01-01

    Understanding the interaction between phenotypic plasticity and evolutionary processes is important for predicting a species' response to changing environment. Strong recurrent selection each generation may be an important process in highly fecund species with broad dispersal and extensive early mortality. We tested whether selection was associated with spatial divergence in gene expression plasticity for osmoregulation in the eastern oyster (Crassostrea virginica). We collected adult oysters from high and low salinity reefs within a single estuary and after 9 weeks of acclimation at 10 and 30 salinity, measured gene expression in 24 oysters using next-generation RNA sequencing technology. The oysters had significantly different expression (DE) in response to salinity treatments for 7936 (18.9%) transcripts overall, with planned contrasts showing 8× more DE in oysters from the high-salinity reef and 15× more DE between reefs when tested at 10 salinity. The reef-by-treatment interaction was also genomically pervasive (5858 DE transcripts, 13.9%). Inter-reef F ST for transcript SNPs averaged 0.0025 with the top 1% between 0.29 and 0.73. Transcripts containing "outlier" SNPs were significantly enriched for osmoregulatory genes and showed patterns of variation consistent with selection on the low-salinity reef. Both phenotypic plasticity and recurrent selection seem to be important factors determining the realized niche of oysters within estuaries.

  12. Modulation of hemocyte activities in oysters (Crassostrea virginica) upon exposure to PAHs

    SciTech Connect

    Chu, F.L.E.; Volety, A.K.; Lingenfelser, J.T.; Hale, R.C.

    1995-12-31

    Hemocyte activities were assessed in oysters exposed to sediment sorbed PAHs. Dose of 0 or 30 g daily for 60 days (Experiment 1) and 0, 60, or 120 g three times/week for 41 days (Experiment 2) were used. In vitro effects of water soluble fractions (WSFs) prepared from sediment collected from a heavily polluted area on the hemocyte activities were also evaluated. To some extent, exposure of oysters to sediment sorbed PAHs (sPAHs) modulated the oyster hemocyte activities. In Experiment 1, 30 day exposure to sPAHs reduced the hemocytes` ability to incorporate {sup 14}C-labeled thymine, uridine and leucine. After 60 days of exposure, the overall uptake of these three components by hemocytes declined in both control and sPAHs exposed oysters and no significant difference was noted. However, after 60 days of exposure, phagocytic, chemotactic and chemiluminescence responses were significantly lower in hemocytes from sPAHs exposed than from control oysters. In Experiment 2, no difference was noted in thymidine, uridine and leucine uptake by oyster hemocytes between 14 and 30 days exposure, but uptake of these compounds increased at the end of the experiment in all groups including controls. Phagocytosis did not differ between treatments nor change with exposure time. No difference was observed in chemiluminescence measured at the end of 41 days among treatments. In vitro exposure of hemocytes to 100% WSF significantly stimulated mitochondrial dehydrogenases production (MTT reduction expressed as % of control), compared to hemocytes exposed to 25 and 50% WSF.

  13. Phaeobacter inhibens as biocontrol agent against Vibrio vulnificus in oyster models.

    PubMed

    Porsby, Cisse Hedegaard; Gram, Lone

    2016-08-01

    Molluscan shellfish can cause food borne diseases and here we investigated if addition of Vibrio-antagonising bacteria could reduce Vibrio vulnificus in model oyster systems and prevent its establishment in live animals. Phaeobacter inhibens, which produces an antibacterial compound, tropodithietic acid (TDA), inhibited V. vulnificus as did pure TDA (MIC of 1-3.9 μM). P. inhibens DSM 17395 (at 10(6) cfu/ml) eradicated 10(5) cfu/ml V. vulnificus CMCP6 (a rifampicin resistant variant) from a co-culture oyster model system (oyster juice) whereas the pathogen grew to 10(7) cfu/ml when co-cultured with a TDA negative Phaeobacter mutant. P. inhibens grew well in oyster juice to 10(8) CFU/ml and sterile filtered samples from these cultures were inhibitory to Vibrio spp. P. inhibens established itself in live European flat oysters (Ostrea edulis) and remained at 10(5) cfu/g for five days. However, the presence of P. inhibens could not prevent subsequently added V. vulnificus from entering the live animals, likely because of too low levels of the biocontrol strain. Whilst the oyster model studies provided indication that P. inhibens DSM 17395 could be a good candidate as biocontrol agent against V. vulnificus further optimization is need in the actual animal rearing situation.

  14. Detection and distribution of ostreid herpesvirus 1 in experimentally infected Pacific oyster spat.

    PubMed

    Segarra, Amélie; Baillon, Laury; Faury, Nicole; Tourbiez, Delphine; Renault, Tristan

    2016-01-01

    High mortality rates are reported in spat and larvae of Pacific oyster Crassostrea gigas and associated with ostreid herpesvirus 1 (OsHV-1) detection in France. Although the viral infection has been experimentally reproduced in oyster larvae and spat, little knowledge is currently available concerning the viral entry and its distribution in organs and tissues. This study compares OsHV-1 DNA and RNA detection and localization in experimentally infected oysters using two virus doses: a low dose that did not induce any mortality and a high dose inducing high mortality. Real time PCR demonstrated significant differences in terms of viral DNA amounts between the two virus doses. RNA transcripts were detected in oysters receiving the highest dose of viral suspension whereas no transcript was observed in oysters injected with the low dose. This study also allowed observing kinetics of viral DNA and RNA detection in different tissues of oyster spat. Finally, viral detection was significantly different in function of tissues (p<0.005), time (p<0.005) with an interaction between tissues and time (p<0.005) for each probe.

  15. Complete mitochondrial genome of the Olympia oyster Ostrea lurida (Bivalvia, Ostreidae).

    PubMed

    Xiao, Shu; Wu, Xiangyun; Li, Lu; Yu, Ziniu

    2015-06-01

    The complete mitochondrial (mt) genome of the Olympia oyster Ostrea lurida (16,344 bp), an economically important bivalve, was newly sequenced and annotated. Ostrea lurida is the largest reported Ostrea oyster mt genomes to date and has a comparatively highest overall A + T content (65%) among the available genomes of marine oysters. High levels of variability of nad2 and nad6 genes and that of major non-coding region (MNR) indicate their potential value as useful molecular markers for population and conservation genetic studies in the future. Phylogenetic analyses based on concatenated nucleotide sequences from all 13 PCGs and 2 rRNA genes show that the European flat oyster Ostrea edulis is sister to the Asian slipper oyster Ostrea denselamellosa, while O. lurida is put at the most basal position of the clade, and indicate that Ostrea are closer to Saccostrea than Crassostrea, although gene arrangement shows a closer relationship between Ostrea and Crassostrea. The observations of the evolutionary pattern of start codon usage among the three congeneric oysters indicate that variation in start codon usage is species-correlated rather than gene-correlated, and to some extent, bears useful phylogenetic information.

  16. The simple neuroendocrine-immune regulatory network in oyster Crassostrea gigas mediates complex functions

    PubMed Central

    Liu, Zhaoqun; Wang, Lingling; Zhou, Zhi; Sun, Ying; Wang, Mengqiang; Wang, Hao; Hou, Zhanhui; Gao, Dahai; Gao, Qiang; Song, Linsheng

    2016-01-01

    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. PMID:27193598

  17. Pesticides and Ostreid Herpesvirus 1 Infection in the Pacific Oyster, Crassostrea gigas

    PubMed Central

    Moreau, Pierrick; Faury, Nicole; Burgeot, Thierry; Renault, Tristan

    2015-01-01

    Since 2008, mass mortality outbreaks have been reported in all French regions producing Pacific oysters, and in several Member States of the European Union. These mass mortality events of Pacific oysters are related to OsHV-1 infection. They occur during spring and summer periods leaving suspect the quality of the marine environment and the role of seasonal use of pesticides associated with the arrival of freshwater in oyster rearing areas. Pesticides have been also detected in French coastal waters, especially in areas of oyster production. Using PMA real-time PCR we showed that a mixture of 14 pesticides has no effect on the integrity of virus capsids from viral suspension in the conditions tested. A contact of oysters with this pesticide mixture was related to higher mortality rates among experimentally infected animals in comparison with control ones (no previous pesticide exposure before experimental infection). We therefore suggest that pesticides at realistic concentration can exert adverse effects on Pacific oysters and causes an increased susceptibility to the viral infection in experimental conditions. PMID:26107171

  18. The simple neuroendocrine-immune regulatory network in oyster Crassostrea gigas mediates complex functions

    NASA Astrophysics Data System (ADS)

    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.

  19. Populations, not clones, are the unit of vibrio pathogenesis in naturally infected oysters

    PubMed Central

    Lemire, Astrid; Goudenège, David; Versigny, Typhaine; Petton, Bruno; Calteau, Alexandra; Labreuche, Yannick; Le Roux, Frédérique

    2015-01-01

    Disease in oysters has been steadily rising over the past decade, threatening the long-term survival of commercial and natural stocks. Our understanding and management of such diseases are of critical importance as aquaculture is an important aspect of dealing with the approaching worldwide food shortage. Although some bacteria of the Vibrio genus isolated from diseased oysters have been demonstrated to be pathogenic by experimental infection, direct causality has not been established. Little is known about the dynamics of how the bacterial population hosted by oysters changes during disease progression. Combining experimental ecology, a high-throughput infection assay and genome sequencing, we show that the onset of disease in oysters is associated with progressive replacement of diverse benign colonizers by members of a phylogenetically coherent virulent population. Although the virulent population is genetically diverse, all members of that population can cause disease. Comparative genomics across virulent and nonvirulent populations identified candidate virulence factors that were clustered in population-specific genomic regions. Genetic analyses revealed that one gene for a candidate virulent factor, a putative outer membrane protein, is necessary for infection of oysters. Finally, analyses of oyster mortality following experimental infection suggest that disease onset can be facilitated by the presence of nonvirulent strains. This is a new form of polymicrobial disease, in which nonpathogenic strains contribute to increase mortality. PMID:25489729

  20. Populations, not clones, are the unit of vibrio pathogenesis in naturally infected oysters.

    PubMed

    Lemire, Astrid; Goudenège, David; Versigny, Typhaine; Petton, Bruno; Calteau, Alexandra; Labreuche, Yannick; Le Roux, Frédérique

    2015-07-01

    Disease in oysters has been steadily rising over the past decade, threatening the long-term survival of commercial and natural stocks. Our understanding and management of such diseases are of critical importance as aquaculture is an important aspect of dealing with the approaching worldwide food shortage. Although some bacteria of the Vibrio genus isolated from diseased oysters have been demonstrated to be pathogenic by experimental infection, direct causality has not been established. Little is known about the dynamics of how the bacterial population hosted by oysters changes during disease progression. Combining experimental ecology, a high-throughput infection assay and genome sequencing, we show that the onset of disease in oysters is associated with progressive replacement of diverse benign colonizers by members of a phylogenetically coherent virulent population. Although the virulent population is genetically diverse, all members of that population can cause disease. Comparative genomics across virulent and nonvirulent populations identified candidate virulence factors that were clustered in population-specific genomic regions. Genetic analyses revealed that one gene for a candidate virulent factor, a putative outer membrane protein, is necessary for infection of oysters. Finally, analyses of oyster mortality following experimental infection suggest that disease onset can be facilitated by the presence of nonvirulent strains. This is a new form of polymicrobial disease, in which nonpathogenic strains contribute to increase mortality.

  1. Growth and reproductive investment of introduced Pacific oysters Crassostrea gigas in southern European waters

    NASA Astrophysics Data System (ADS)

    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.

  2. Biomarkers of dissolved oxygen stress in oysters: a tool for restoration and management efforts.

    PubMed

    Patterson, Heather K; Boettcher, Anne; Carmichael, Ruth H

    2014-01-01

    The frequency and intensity of anoxic and hypoxic events are increasing worldwide, creating stress on the organisms that inhabit affected waters. To understand the effects of low dissolved oxygen stress on oysters, hatchery-reared oysters were placed in cages and deployed along with continuously recording environmental data sondes at a reef site in Mobile Bay, AL that typically experiences low oxygen conditions. To detect and measure sublethal stress, we measured growth and survival of oysters as well as expression of three biomarkers, heat shock protein 70 (HSP70), hypoxia inducible factor (HIF) and phospho-p38 MAP kinase, in tissues from juvenile and adult oysters. Survival rates were high for both juvenile and adult oysters. Expression levels of each of the 3 isoforms of HSP 70 were negatively correlated to dissolved oxygen (DO) concentrations, suggesting that HSP 70 is useful to quantify sublethal effects of DO stress. Results for HIF and phospho-p38 MAP kinase were inconclusive. Test deployments of oysters to assess expression of HSP 70 relative to environmental conditions will be useful, in addition to measuring abiotic factors, to identify appropriate sites for restoration, particularly to capture negative effects of habitat quality on biota before lethal impacts are incurred.

  3. A survey of Australian oysters for the presence of human noroviruses.

    PubMed

    Brake, Felicity; Ross, Tom; Holds, Geoffrey; Kiermeier, Andreas; McLeod, Catherine

    2014-12-01

    Impending international policies for norovirus in oysters and the lack of Australian data suggested there was a need to undertake a national survey of norovirus in oysters. Two geographically distinct oyster-growing areas from each of three Australian states were sampled on 4 occasions during 2010 and 2011. The sites selected were considered by state shellfish authorities to be the most compromised with respect to the potential for human faecal contamination as identified by shoreline surveys. The oysters were tested for norovirus GI, GII and Escherichia coli. Norovirus GII was detected in two of 120 (1.7%) samples and norovirus GI was not detected. One of the norovirus positive samples was cloned and sequenced as GII.3. Five of 120 (4.2%) samples were found to have more than the guidance concentration of 230 E. coli per 100 g of shellfish but these samples did not contain detectable concentrations of norovirus. The apparently low prevalence of norovirus in oysters from Australian growing areas supports epidemiological data that suggests norovirus contamination of Australian oysters is rare. The results from this study emphasise the need for future norovirus control measures for shellfish to be commensurate with the risk associated with the growing area.

  4. Distinct immune responses of juvenile and adult oysters (Crassostrea gigas) to viral and bacterial infections.

    PubMed

    Green, Timothy J; Vergnes, Agnes; Montagnani, Caroline; de Lorgeril, Julien

    2016-07-21

    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.

  5. Ostreid herpesvirus type 1 replication and host response in adult Pacific oysters, Crassostrea gigas.

    PubMed

    Segarra, Amélie; Baillon, Laury; Tourbiez, Delphine; Benabdelmouna, Abdellah; Faury, Nicole; Bourgougnon, Nathalie; Renault, Tristan

    2014-10-08

    Since 2008, massive mortality outbreaks associated with OsHV-1 detection have been reported in Crassostrea gigas spat and juveniles in several countries. Nevertheless, adult oysters do not demonstrate mortality in the field related to OsHV-1 detection and were thus assumed to be more resistant to viral infection. Determining how virus and adult oyster interact is a major goal in understanding why mortality events are not reported among adult Pacific oysters. Dual transcriptomics of virus-host interactions were explored by real-time PCR in adult oysters after a virus injection. Thirty-nine viral genes and five host genes including MyD88, IFI44, IkB2, IAP and Gly were measured at 0.5, 10, 26, 72 and 144 hours post infection (hpi). No viral RNA among the 39 genes was detected at 144 hpi suggesting the adult oysters are able to inhibit viral replication. Moreover, the IAP gene (oyster gene) shows significant up-regulation in infected adults compared to control adults. This result suggests that over-expression of IAP could be a reaction to OsHV-1 infection, which may induce the apoptotic process. Apoptosis could be a main mechanism involved in disease resistance in adults. Antiviral activity of haemolymph against herpes simplex virus (HSV-1) was not significantly different between infected adults versus control.

  6. Detection of Vibrio vulnificus biotypes 1 and 2 in eels and oysters by PCR amplification.

    PubMed

    Coleman, S S; Melanson, D M; Biosca, E G; Oliver, J D

    1996-04-01

    DNA extraction procedures and PCR conditions to detect Vibrio vulnificus cells naturally occurring in oysters were developed. In addition, PCR amplification of V. vulnificus from oysters seeded with biotype 1 cells was demonstrated. By the methods described, V. vulnificus cells on a medium (colistin-polymyxin B-cellobiose agar) selective for this pathogen were detectable in oysters harvested in January and March, containing no culturable cells (< 67 CFU/g), as well as in oysters harvested in May and June, containing culturable cells. It was possible to complete DNA extraction, PCR, and gel electrophoresis within 10 h by using the protocol described for oysters. V. vulnificus biotype 2 cells were also detected in eel tissues that had been infected with this strain and subsequently preserved in formalin. The protocol used for detection of V. vulnificus cells in eels required less than 5 h to complete. Optimum MgCl2 concentrations for the PCR of V. vulnificus from oysters and eels were different, although the same primer pair was used for both. This is the first report on the detection of cells of V. vulnificus naturally present in shellfish and represents a potentially powerful method for monitoring this important human and eel pathogen.

  7. Geohistorical records indicate no impact of the Deepwater Horizon oil spill on oyster body size.

    PubMed

    Dietl, Gregory P; Durham, Stephen R

    2016-11-01

    Documentation of the near- and long-term effects of the Deepwater Horizon (DWH) oil spill, one of the largest environmental disasters in US history, is still ongoing. We used a novel before-after-control-impact analysis to test the hypothesis that average body size of intertidal populations of the eastern oyster (Crassostrea virginica) inhabiting impacted areas in Louisiana decreased due to increased stress/mortality related to the oil spill. Time-averaged death assemblages of oysters were used to establish a pre-spill baseline of body-size structure for four impacted and four control locations along a 350 km stretch of Louisiana's coastline. Post-spill body sizes were then measured from live oysters at each site in order to evaluate the differences in body size between oiled (i.e. impact) and unoiled (i.e. control) locations before and after the spill. Our results indicate that average body size of oysters remained relatively unchanged after the oil spill. There were also no temporal patterns in temperature, salinity or disease prevalence that could have explained our results. Together, these findings suggest that oysters either recovered rapidly following the immediate impact of the DWH oil spill, or that its impact was not severe enough to influence short-term population dynamics of the oyster beds.

  8. Pesticides and Ostreid Herpesvirus 1 Infection in the Pacific Oyster, Crassostrea gigas.

    PubMed

    Moreau, Pierrick; Faury, Nicole; Burgeot, Thierry; Renault, Tristan

    2015-01-01

    Since 2008, mass mortality outbreaks have been reported in all French regions producing Pacific oysters, and in several Member States of the European Union. These mass mortality events of Pacific oysters are related to OsHV-1 infection. They occur during spring and summer periods leaving suspect the quality of the marine environment and the role of seasonal use of pesticides associated with the arrival of freshwater in oyster rearing areas. Pesticides have been also detected in French coastal waters, especially in areas of oyster production. Using PMA real-time PCR we showed that a mixture of 14 pesticides has no effect on the integrity of virus capsids from viral suspension in the conditions tested. A contact of oysters with this pesticide mixture was related to higher mortality rates among experimentally infected animals in comparison with control ones (no previous pesticide exposure before experimental infection). We therefore suggest that pesticides at realistic concentration can exert adverse effects on Pacific oysters and causes an increased susceptibility to the viral infection in experimental conditions.

  9. The simple neuroendocrine-immune regulatory network in oyster Crassostrea gigas mediates complex functions.

    PubMed

    Liu, Zhaoqun; Wang, Lingling; Zhou, Zhi; Sun, Ying; Wang, Mengqiang; Wang, Hao; Hou, Zhanhui; Gao, Dahai; Gao, Qiang; Song, Linsheng

    2016-05-19

    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 [Met(5)]-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 [Met(5)]-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.

  10. Predatory blue crabs induce stronger nonconsumptive effects in eastern oysters Crassostrea virginica than scavenging blue crabs

    PubMed Central

    Garcia, Miranda M.; Smee, Delbert L.

    2017-01-01

    By influencing critical prey traits such as foraging or habitat selection, predators can affect entire ecosystems, but the nature of cues that trigger prey reactions to predators are not well understood. Predators may scavenge to supplement their energetic needs and scavenging frequency may vary among individuals within a species due to preferences and prey availability. Yet prey reactions to consumers that are primarily scavengers versus those that are active foragers have not been investigated, even though variation in prey reactions to scavengers or predators might influence cascading nonconsumptive effects in food webs. Oysters Crassostrea virginica react to crab predators by growing stronger shells. We exposed oysters to exudates from crabs fed live oysters or fed aged oyster tissue to simulate scavenging, and to controls without crab cues. Oysters grew stronger shells when exposed to either crab exudate, but their shells were significantly stronger when crabs were fed live oysters. The stronger response to predators than scavengers could be due to inherent differences in diet cues representative of reduced risk in the presence of scavengers or to degradation of conspecific alarm cues in aged treatments, which may mask risk from potential predators subsisting by scavenging. PMID:28265512

  11. Comparative and quantitative proteomics reveal the adaptive strategies of oyster larvae to ocean acidification.

    PubMed

    Dineshram, R; Quan, Q; Sharma, Rakesh; Chandramouli, Kondethimmanahalli; Yalamanchili, Hari Krishna; Chu, Ivan; Thiyagarajan, Vengatesen

    2015-12-01

    Decreasing pH due to anthropogenic CO2 inputs, called ocean acidification (OA), can make coastal environments unfavorable for oysters. This is a serious socioeconomical issue for China which supplies >70% of the world's edible oysters. Here, we present an iTRAQ-based protein profiling approach for the detection and quantification of proteome changes under OA in the early life stage of a commercially important oyster, Crassostrea hongkongensis. Availability of complete genome sequence for the pacific oyster (Crassostrea gigas) enabled us to confidently quantify over 1500 proteins in larval oysters. Over 7% of the proteome was altered in response to OA at pHNBS 7.6. Analysis of differentially expressed proteins and their associated functional pathways showed an upregulation of proteins involved in calcification, metabolic processes, and oxidative stress, each of which may be important in physiological adaptation of this species to OA. The downregulation of cytoskeletal and signal transduction proteins, on the other hand, might have impaired cellular dynamics and organelle development under OA. However, there were no significant detrimental effects in developmental processes such as metamorphic success. Implications of the differentially expressed proteins and metabolic pathways in the development of OA resistance in oyster larvae are discussed. The MS proteomics data have been deposited to the ProteomeXchange with identifiers PXD002138 (http://proteomecentral.proteomexchange.org/dataset/PXD002138).

  12. Oyster-based national mapping of trace metals pollution in the Chinese coastal waters.

    PubMed

    Lu, Guang-Yuan; Ke, Cai-Huan; Zhu, Aijia; Wang, Wen-Xiong

    2017-03-02

    To investigate the distribution and variability of trace metal pollution in the Chinese coastal waters, over 1000 adult oyster individuals were collected from 31 sites along the entire coastline, spanning from temperate to tropical regions (Bohai Sea, Yellow Sea, East China Sea and South China Sea), between August and September 2015. Concentrations of macroelements [sodium (Na), potassium (K), calcium (Ca), magnesium (Mg) and phosphorus (P)] and trace elements [cadmium (Cd), copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), chromium (Cr), silver (Ag), and titanium (Ti)] in these oysters were concurrently measured and analyzed. The results showed high Ti, Zn and Cu bioaccumulation in oysters from Guangdong (South China Sea) and Zhejiang (East China Sea). Oysters at Nanji Island (Wenzhou) and Daya Bay (Huizhou) accumulated significantly high concentrations of Ni and Cr. The elements in these oysters were several times higher than the national food safety limits of China. On the other hand, the present study found that normalization of metals by salinity (Na) and nutrient (P) could reflect more details of metal pollution in the oysters. Biomonitoring of metal pollution could benefit from incorporating the macroelement calibration instead of focusing only on the total metal concentrations. Overall, simultaneous measurement of macroelements and trace metals coupled with non-linear analysis provide a new perspective for revealing the underlying mechanism of trace metal bioavailability and bioaccumulation in marine organisms.

  13. The Effects of Salinity on the Filtration Rates of Juvenile Tropical Oyster Crassostrea iredalei

    PubMed Central

    Chang, Geraldine Olive Ju Lien; Inn, Lai Ven; Hwai, Aileen Tan Shau; Yasin, Zulfigar

    2016-01-01

    A small scale laboratory study was conducted to determine the effects of salinity ranging from 15, 20, 25, 30, 35, 40, and 45 ppt on the filtration rates of juvenile oyster Crassostrea iredalei with 25 ppt as the control. Three juvenile oysters (shell weight: 1.04 ± 0.12 g; shell length: 1.9 ± 0.2 cm; shell height: 1.9 ± 0.1 cm) were used to test the filtration rates in each salinity over the course of 8 hours. The hourly filtration rates were determined from the exponential decrease in algal (Chaetoceros calcitrans) concentration as a function of time. The oyster in 35 ppt salinity produced the highest overall filtration rate (FR2) with 134.06 ± 15.66 mL−1 hr−1 oyster−1 and the lowest overall filtration rate (FR2) occurred in oyster exposed to 15 ppt and 45 ppt with 31.30 ± 6.90 mL−1 hr−1 oyster−1 and 32.11 ± 7.68 mL−1 hr−1 oyster−1 respectively throughout the 8 hours. The result from this study can be useful for optimum oyster culturing and the oysters can be employed as a natural biofilter in marine polyculture farming. PMID:27965740

  14. Ocean acidification increases the vulnerability of native oysters to predation by invasive snails

    PubMed Central

    Sanford, Eric; Gaylord, Brian; Hettinger, Annaliese; Lenz, Elizabeth A.; Meyer, Kirstin; Hill, Tessa M.

    2014-01-01

    There is growing concern that global environmental change might exacerbate the ecological impacts of invasive species by increasing their per capita effects on native species. However, the mechanisms underlying such shifts in interaction strength are poorly understood. Here, we test whether ocean acidification, driven by elevated seawater pCO2, increases the susceptibility of native Olympia oysters to predation by invasive snails. Oysters raised under elevated pCO2 experienced a 20% increase in drilling predation. When presented alongside control oysters in a choice experiment, 48% more high-CO2 oysters were consumed. The invasive snails were tolerant of elevated CO2 with no change in feeding behaviour. Oysters raised under acidified conditions did not have thinner shells, but were 29–40% smaller than control oysters, and these smaller individuals were consumed at disproportionately greater rates. Reduction in prey size is a common response to environmental stress that may drive increasing per capita effects of stress-tolerant invasive predators. PMID:24430847

  15. Fluxomics of the Eastern Oyster for Environmental Stress Studies

    PubMed Central

    Tikunov, Andrey P.; Stoskopf, Michael K.; Macdonald, Jeffrey M.

    2014-01-01

    The metabolism of 2-13C/15N-glycine and U-13C-glucose was determined in four tissue blocks (adductor muscle, stomach and digestive gland, mantle, and gills) of the Eastern oyster (Crassostrea virginica) using proton (1H) and carbon-13 (13C) nuclear magnetic resonance (NMR) spectroscopy. The oysters were treated in aerated seawater with three treatments (5.5 mM U-13C-glucose, 2.7 mM 2-13C/15N-glycine, and 5.5 mM U-13C-glucose plus 2.7 mM 2-13C/15N-glycine) and the relative mass balance and 13C fractional enrichments were determined in the four tissue blocks. In all tissues, glycine was metabolized by the glycine cycle forming serine exclusively in the mitochondria by the glycine cleavage system forming 2,3-13C-serine. In muscle, a minor amount of serine-derived pyruvate entered the Krebs cycle as substantiated by detection of a trace of 2,3-13C-aspartate. In all tissues, U-13C-glucose formed glycogen by glycogen synthesis, alanine by glycolysis, and glutamate and aspartate through the Krebs cycle. Alanine was formed exclusively from glucose via alanine transaminase and not glycine via alanine-glyoxylate transaminase. Based on isotopomer analysis, pyruvate carboxylase and pyruvate dehydrogenase appeared to be equal points for pyruvate entry into the Krebs cycle. In the 5.5 mM U-13C-glucose plus 2.7 mM 2-13C/15N-glycine emergence treatment used to simulate 12 h of “low tide”, oysters accumulated more 13C-labeled metabolites, including both anaerobic glycolytic and aerobic Krebs cycle intermediates. The aerobic metabolites could be the biochemical result of the gaping behavior of mollusks during emergence. The change in tissue distribution and mass balance of 13C-labeled nutrients (U-13C-glucose and 2-13C/15N-glycine) provides the basis for a new quantitative fluxomic method for elucidating sub-lethal environmental effects in marine organisms called whole body mass balance phenotyping (WoMBaP). PMID:24958387

  16. The use of transplanted cultured tropical oysters (Saccostrea commercialis) to monitor Cd levels in North Queensland coastal waters (Australia).

    PubMed

    Olivier, Frédérique; Ridd, Michael; Klumpp, David

    2002-10-01

    Bivalves are commonly used to detect metal pollution in the marine environment. Commercially cultured Milky oysters (Saccostrea commercialis) were transplanted in various sites along the North Queensland coast and analyzed for two metals of potentially anthropogenic origin (Cd, Zn). To provide additional information, naturally occurring Black Lip oysters (Saccostrea echinata) were also collected at the transplantation sites. The study demonstrated that the oysters species transplanted are good bioindicators of these metal concentrations in tropical waters, sensitive to variations in the environment at concentrations which are much smaller than pollution signals commonly reported for temperate waters. Three transplant experiments were carried out from May 1999 to February 2000. Milky oysters transplanted to offshore areas (Orpheus Is., Kelso Reef) accumulated Cd in the soft parts whereas oysters sampled from cages placed in Ross Creek and the Herbert River estuaries showed a decrease in Cd concentration, which resulted from an increase in dry weight. Dry weight appeared to be an important covariant affecting Cd concentration in the oysters whereas it does not unambiguously affect Zn concentrations. For the duration of the experiments, oysters sampled from the Magnetic Is. reference site showed effectively constant Cd concentrations and total Cd contents which indicates that any seasonal cycle affecting metal concentration is weak. It was found that Cd accumulation in oysters increased as ambient dissolved Cd concentration decreased, from which it was concluded that for these oysters, the predominant source of Cd was from the particulate phase rather than the dissolved phase.

  17. Cadmium Bioaccumulation in European Flat Oysters (Ostrea Edulis) from Middle Adriatic Sea (San Benedetto Del Tronto District, Italy)

    PubMed Central

    Semeraro, Angela Marisa; Aliventi, Alessandra; Di Trani, Vittoria; Capocasa, Piero

    2014-01-01

    Bivalve molluscs represent an important source of cadmium exposure in humans, in particular oysters, because of their high filter feeding capability and high concentration of metal-binding metallothionein in tissues. In this study the authors investigated the difference in cadmium bioaccumulation in European flat oysters harvested from production areas in the district of San Benedetto del Tronto (Ascoli Piceno province, Italy), as a function of their origin (farming or natural beds) and the time of gathering. The beds lie 3 nm off-shore at a depth of 20-40 m and are collected by dredging. In the farms, baskets are suspended in the water column 2.5-3 nm offshore at a depth of 4 m. The authors analysed the results of cadmium monitoring plan carried out in oyster natural beds for a total of 15 samples collected from 2004 to 2012 and in two oyster farms for a total of 11 samples from 2009 to 2012. Although the few data did not allow to find a significant statistical association, they suggested two findings: i) cadmium concentration in oysters from natural beds seemed to be lower than in farmed oysters; and ii) in farmed oysters cadmium concentration even exceeded allowed maximum level for human consumption, in particular in autumn. The vertical stratification in the water column of phytoplankton and a cadmium dilution at oyster gonadal maturation might cause changes in oyster cadmium accumulation. PMID:27800338

  18. Investigating oyster shell thickness and strength using three imaging modalities: hyperspectral imaging, thermal imaging and digital photography

    NASA Astrophysics Data System (ADS)

    Mehrübeoglu, Mehrube; Smith, Dustin K.; Smith, Shane W.; Smee, Delbert L.; Simionescu, Petru-Aurelian

    2013-09-01

    A comparative study of three imaging technologies has been conducted to nondestructively assess the thickness and strength of oyster shells grown in various environmental conditions. Oyster shell thickness and strength are expected to be dependent on the harshness of the oyster's environment as well as other factors. Oysters have been grown in environments with and without predators, and within and out of tidal zones. Hyperspectral imaging has been used to detect possible differences in hyperspectral properties among oyster shells from each of the four environments. Thermal Imaging has been utilized to identify hot spots in the shells based on the principles of heat capacitance, indicating density or thickness of the shells. Finally, a visible-range digital photographic camera has been used to obtain digital images. The three technologies are compared to evaluate the effectiveness of each technology in identifying oyster shell thickness and strength. Although oyster shell thickness and strength are related, they may not be exactly correlated. The local thickness of the oyster shells have been measured with a micro caliper, and shells broken with a crush tester to establish a baseline and ground truth for average shell thickness and shell strength, respectively. The preliminary results from the three methods demonstrate that thermal imaging correlates the best with the invasive strength test results and weight measurements. Using hyperspectral data and principal component analysis, classification of the four oyster shell groups were achieved. Visible-range images mainly provided size, shape, color and texture information.

  19. Microbiological quality and bacterial diversity of the tropical oyster Crassostrea rhizophorae in a monitored farming system and from natural stocks.

    PubMed

    Silva Neta, M T; Maciel, B M; Lopes, A T S; Marques, E L S; Rezende, R P; Boehs, G

    2015-12-02

    Microbiological evaluation is one of the most important parameters for analyzing the viability of an oyster farming system, which addresses public health and ecological concerns. Here, the microbiological quality of the oyster Crassostrea rhizophorae cultivated in a monitored environment and from natural beds in Bahia, northeastern Brazil, was determined. Bacterial diversity in oysters was measured by polymerase chain reaction-denaturing gradient gel electrophoresis. Sequence analysis revealed that most bacterial species showed similarity with uncultured or unidentified bacteria from environmental samples, and were clustered into the phylum Proteobacteria. Diverse bacteria from cultivated (monitored) oyster samples were grouped in the same cluster with a high similarity index (above 79%). Microbiological analyses revealed that these oysters did not contain pathogens. These results reflect the natural balance of the microbial communities essential to the maintenance of health and in inhibiting pathogen colonization in the oyster. On the other hand, bacterial diversity of samples from native stocks in extractive areas displayed a similarity index varying between 55 and 77%, and all samples were clustered separately from each other and from the cluster of samples derived from the cultivation area. Microbiological analyses showed that oysters from the extractive area were not fit for human consumption. This reflected a different composition of the microbial community in this area, probably resulting from anthropic impact. Our study also demonstrated that low temperatures and high rainfall limits the bacterial concentration in tropical oysters. This is the first study analyzing the total bacterial community profiles of the oyster C. rhizophorae.

  20. Bacterial microbiota profile in gills of modified atmosphere-packaged oysters stored at 4 °C.

    PubMed

    Chen, Huibin; Wang, Meiying; Lin, Xiangzhi; Shi, Caihua; Liu, Zhiyu

    2017-02-01

    As filter-feeding bivalves, oysters can accumulate microorganisms into their gills, causing spoilage and potential safety issues. This study aims to investigate the changes in the gill microbiota of oysters packed under air and modified atmospheres (MAs, 50% CO2: 50% N2, 70% CO2: 30% O2, and 50% CO2: 50% O2) during storage at 4 °C. The diversity of bacterial microbiota in oyster gills was profiled through polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis on the 16S rRNA gene V3 region to describe the variation during the entire storage period. The DGGE profile revealed high bacterial diversity in the air- and MA-packaged oyster gills, and the spoilage bacterial microbiota varied in the MA-packaged oyster gills. Results indicated that CO2:O2 (70%:30%) was suitable for oyster MA packaging and that high bacterial loads in oyster gills need to be considered during storage. In addition, Lactobacillus and Lactococcus species were found to grow dominantly in fresh oyster gills under MA packaging, which supports the potential application of MA packaging for oyster storage.

  1. Digital feedwater and recirculation flow control for GPUN Oyster Creek

    SciTech Connect

    Burjorjee, D. ); Gan, B. )

    1992-01-01

    This paper describes the digital system for feedwater and recirculation control that GPU Nuclear will be installing at Oyster Creek during its next outage - expected circa December 1992. The replacement was motivated by considerations of reliability and obsolescence - the analog equipment was aging and reaching the end of its useful life. The new system uses Atomic Energy of Canada Ltd.'s software platform running on dual, redundant, industrial-grade 386 computers with opto-isolated field input/output (I/O) accessed through a parallel bus. The feedwater controller controls three main feed regulating valves, two low flow regulating valves, and two block valves. The recirculation controller drives the five scoop positioners of the hydraulic couplers. The system also drives contacts that lock up the actuators on detecting an open circuit in their current loops.

  2. Oyster toadfish fly on STS-90 as part of Neurolab

    NASA Technical Reports Server (NTRS)

    1998-01-01

    An oyster toadfish (Opsanus tau), like those that are part of the Neurolab payload on Space Shuttle Mission STS-90, is shown in its holding tank in the Space Station Processing Facility. Each fish is between eight and 14 inches long. Toadfish live in an estuarine environment and are native to areas along the Northeast coast of the United States. Investigations during the Neurolab mission will focus on the effects of microgravity on the nervous system. This fish is an excellent model for looking at vestibular function because the architecture of its inner and middle ear are similar to those of mammals with respect to the vestibular apparatus. The crew of STS-90, slated for launch April 16 at 2:19 p.m. EDT, includes Commander Richard Searfoss, Pilot Scott Altman, Mission Specialists Richard Linnehan, Dafydd (Dave) Williams, M.D., and Kathryn (Kay) Hire, and Payload Specialists Jay Buckey, M.D., and James Pawelczyk, Ph.D.

  3. Infectious diseases in oyster aquaculture require a new integrated approach.

    PubMed

    Pernet, Fabrice; Lupo, Coralie; Bacher, Cédric; Whittington, Richard J

    2016-03-05

    Emerging diseases pose a recurrent threat to bivalve aquaculture. Recently, massive mortality events in the Pacific oyster Crassostrea gigas associated with the detection of a microvariant of the ostreid herpesvirus 1 (OsHV-1µVar) have been reported in Europe, Australia and New Zealand. Although the spread of disease is often viewed as a governance failure, we suggest that the development of protective measures for bivalve farming is presently held back by the lack of key scientific knowledge. In this paper, we explore the case for an integrated approach to study the management of bivalve disease, using OsHV-1 as a case study. Reconsidering the key issues by incorporating multidisciplinary science could provide a holistic understanding of OsHV-1 and increase the benefit of research to policymakers.

  4. Infectious diseases in oyster aquaculture require a new integrated approach

    PubMed Central

    Lupo, Coralie; Whittington, Richard J.

    2016-01-01

    Emerging diseases pose a recurrent threat to bivalve aquaculture. Recently, massive mortality events in the Pacific oyster Crassostrea gigas associated with the detection of a microvariant of the ostreid herpesvirus 1 (OsHV-1µVar) have been reported in Europe, Australia and New Zealand. Although the spread of disease is often viewed as a governance failure, we suggest that the development of protective measures for bivalve farming is presently held back by the lack of key scientific knowledge. In this paper, we explore the case for an integrated approach to study the management of bivalve disease, using OsHV-1 as a case study. Reconsidering the key issues by incorporating multidisciplinary science could provide a holistic understanding of OsHV-1 and increase the benefit of research to policymakers. PMID:26880845

  5. The discrepancy in concentration of metals (Cu, Pb and Zn) in oyster tissue (Saccostrea glomerata) and ambient bottom sediment (Sydney estuary, Australia).

    PubMed

    Birch, G F; Melwani, A; Lee, J-H; Apostolatos, C

    2014-03-15

    The current study aimed to examine the relationship between metals in sediments and metal bioaccumulation in oyster tissue in a highly-modified estuary (Sydney estuary, Australia). While extensive metal contamination was observed in surficial sediments, suspended particulate matter and oyster tissue, a significant relationship between these media could not be established. No relationship was determined between sediment quality guidelines and oyster size or weight, nor with human consumption levels for metals in oyster tissue. Moreover, oyster tissue metal concentrations varied greatly at a single locality over temporal scales of years. Oyster tissue at all 19 study sites exceeded consumptions levels for Cu. Bioaccumulation of metals in oyster tissue is a useful dynamic indicator of anthropogenic influence within estuaries, however oysters cannot be used in Sydney estuary as a valid biomonitor due to overriding internal regulation (homoestasis) by the animal, or by external natural (sediment resuspension) and anthropogenic (sewer/stormwater discharges) pressures, or both.

  6. Successful cryopreservation of Pacific oyster (Crassostrea gigas) oocytes.

    PubMed

    Tervit, H R; Adams, S L; Roberts, R D; McGowan, L T; Pugh, P A; Smith, J F; Janke, A R

    2005-10-01

    Protocols for cryopreservation of sperm and oocytes would provide the ultimate control over parental crosses in selective breeding programmes. Sperm freezing is routine for many species, but oocyte freezing remains problematic, with virtually zero success in aquatic species to date. This paper describes the development of a successful protocol for cryopreserving high concentrations of Pacific oyster (Crassostrea gigas) oocytes. Ethylene glycol (10%) and dimethyl sulfoxide (15%) were found to be the most effective cryoprotectants resulting in post-thaw fertilization rates of 51.0+/-8.0 and 45.1+/-8.3%, respectively. Propylene glycol was less effective and methanol resulted in zero fertilization post-thaw. The use of Milli-Q water rather than seawater as a base medium significantly improved fertilization (20.4+/-3.0 and 8.7+/-2.2%, respectively) as did the inclusion of a 5 min isothermal hold at -10 or -12 degrees C (35.9+/-5.0 and 31.9+/-4.6%, respectively). The optimal cooling rate post-hold was 0.3 degrees C min(-1), with virtually zero post-thaw fertilization with cooling rates of 3 and 6 degrees C min(-1). Using an optimized protocol, post-thaw fertilization rates for oocytes from eight individual females ranged from 0.8 to 74.5% and D-larval yields from 0.1 to 30.1%. For three individuals, larvae were reared through to spat. Development of D-larvae to eyed larvae and spat was similar for larvae produced from unfrozen (24.8+/-4.1% developed to eyed larvae and 16.5+/-3.2% to spat) and cryopreserved (28.4+/-0.6 and 18.7+/-0.5%, respectively) oocytes. The ability to cryopreserve large quantities of oyster oocytes represents a major advance in cryobiology and selective breeding.

  7. Functional characterisation of phagocytes in the Pacific oyster Crassostrea gigas

    PubMed Central

    Jiang, Shuai; Jia, Zhihao; Zhang, Tao; Wang, Lingling; Qiu, Limei; Sun, Jinsheng

    2016-01-01

    Invertebrates lack canonical adaptive immunity and mainly rely on innate immune system to fight against pathogens. The phagocytes, which could engulf and kill microbial pathogens, are likely to be of great importance and have to undertake significant roles in invertebrate immune defense. In the present study, flow cytometry combined with histological and lectin staining was employed to characterise functional features of phagocytes in the Pacific oyster Crassostrea gigas. Based on the cell size and cellular contents, haemocytes were categorised into three cell types, i.e., granulocytes, semigranulocytes and agranulocytes. Agranulocytes with smaller cell volume and lower cytoplasmic-to-nuclear ratio did not show phagocytic activity, while semigranulocytes and agranulocytes exhibited larger cell volume, higher cytoplasmic-to-nuclear ratio and phagocytic activity. In addition, granulocytes with higher side scatter (SSC) exhibited higher phagocytic activity than that of semigranulocytes. When β-integrin and lectin-like receptors were blocked by RGD tripeptide and carbohydrates, respectively, the phagocytic activity of both granulocytes and semigranulocytes was significantly inhibited, indicating that β-integrin and certain lectin-like receptors were involved in phagocytosis towards microbes. Moreover, lipopolysaccharide but not peptidylglycan could enhance phagocytic activity of granulocytes and semigranulocytes towards Vibrio splendidus and Staphylococcus aureus. Lectin staining analysis revealed that Lycopersicon esculentum lectin (LEL), binding the epitope polylactosamine, was highly distributed on the extracellular cell surface of phagocytes, and could be utilized as a potential molecular marker to differentiate phagocytes from non-phagocytic haemocytes. The results, collectively, provide knowledge on the functional characters of oyster phagocytes, which would contribute to deep investigation of cell typing and cellular immunity in bivalves. PMID:27994957

  8. Enhanced Detection of Vibrio Cholerae in Oyster Homogenate Based on Centrifugal Removal of Inhibitory Agents

    NASA Technical Reports Server (NTRS)

    Alexander, Donita; DePaola, Angelo; Young, Ronald B.

    1998-01-01

    The disease cholera, caused by Vibrio cholerae, has been associated with consumption of contaminated seafood, including raw oysters. Detection of V. cholerae in foods typically involves blending the oysters, diluting the homogenate in alkaline peptone water (APW), overnight enrichment, and isolation on selective agar. Unfortunately, the oyster homogenate must be diluted to large volumes because lower dilutions inhibit the growth of V. cholerae. The goals of this study were to develop an alternative to large dilutions and to evaluate the basis for the inhibition observed in lower dilutions of oyster homogenates. Centrifugation of oyster homogenates at 10,000 x g for 15 min, followed by enrichment of the resulting pellet in APW, was found to eliminate the inhibition of V. cholerae growth. Inhibition appears not to be due to competing microflora but to a component(s) released when V. cholerae grows in the presence of oyster homogenate. The inhibitory component(s) kills the V. cholerae after the cell concentration reaches > 10(exp 8) cells/mL, rather than initially preventing their growth. The pH also declines from 8.0 to 5.5 during this period; however, the pH decline by itself appears not to cause V. cholerae death. Seven strains of V. cholerae (01 and non-01) and two strains of V. vulnificus were susceptible to the inhibitory agent(s). However, other Vibrio and non-Vibrio species tested were not inhibited by the oyster homogenates. Based on digestion of oyster homogenates with pronase, trypsin and lipase, the inhibitory reaction involves a protein(s). In a preliminary trial with oyster homogenate seeded with 1 cfu/g of V. cholerae, the modified centrifugation technique detected a slightly higher percentage of samples at a 1:10 dilution than the standard FDA Bacteriological Analytical Method (BAM) detected in uncentrifuged oyster homogenate at a 1:100 dilution. V. cholerae in seeded samples could also be detected more frequently by the modified centrifugation method

  9. Oyster larvae settle in response to habitat-associated underwater sounds.

    PubMed

    Lillis, Ashlee; Eggleston, David B; Bohnenstiehl, DelWayne R

    2013-01-01

    Following a planktonic dispersal period of days to months, the larvae of benthic marine organisms must locate suitable seafloor habitat in which to settle and metamorphose. For animals that are sessile or sedentary as adults, settlement onto substrates that are adequate for survival and reproduction is particularly critical, yet represents a challenge since patchily distributed settlement sites may be difficult to find along a coast or within an estuary. Recent studies have demonstrated that the underwater soundscape, the distinct sounds that emanate from habitats and contain information about their biological and physical characteristics, may serve as broad-scale environmental cue for marine larvae to find satisfactory settlement sites. Here, we contrast the acoustic characteristics of oyster reef and off-reef soft bottoms, and investigate the effect of habitat-associated estuarine sound on the settlement patterns of an economically and ecologically important reef-building bivalve, the Eastern oyster (Crassostrea virginica). Subtidal oyster reefs in coastal North Carolina, USA show distinct acoustic signatures compared to adjacent off-reef soft bottom habitats, characterized by consistently higher levels of sound in the 1.5-20 kHz range. Manipulative laboratory playback experiments found increased settlement in larval oyster cultures exposed to oyster reef sound compared to unstructured soft bottom sound or no sound treatments. In field experiments, ambient reef sound produced higher levels of oyster settlement in larval cultures than did off-reef sound treatments. The results suggest that oyster larvae have the ability to respond to sounds indicative of optimal settlement sites, and this is the first evidence that habitat-related differences in estuarine sounds influence the settlement of a mollusk. Habitat-specific sound characteristics may represent an important settlement and habitat selection cue for estuarine invertebrates and could play a role in driving

  10. Detection of oyster habitat in tidal flats using multi-frequency polarimetric SAR data

    NASA Astrophysics Data System (ADS)

    Choe, Byung-Hun; Kim, Duk-jin; Hwang, Ji-Hwan; Oh, Yisok; Moon, Wooil M.

    2012-01-01

    Exposed oyster reefs in tidal flats have complex and rough surfaces because of their unique surface texture, which are quite distinct from the surrounding mud or sand flats. Here we investigate the microwave signatures, backscattered from naturally distributed oyster reefs in tidal flats, utilizing the polarimetric analysis techniques to fully polarimetric RADARSAT-2 (C-band) and ALOS PALSAR (L-band) data. The study areas include the tidal flats around Jebu Island and Hampyung Bay on the west coast of the Korean peninsula. We analyzed the microwave scattering mechanisms associated with oyster reefs and surrounding areas using the polarimetric target decomposition theorem and quantitatively measu ρHHVV red target depolarization effects (the cross-polarized ratio (HV/VV), the co-polarized correlation coefficient ( ρHHVV), and the co-polarized phase difference between HH and VV). On the basis of a large increase in the cross-polarized backscattering (HV) in the C-band SAR data, one can observe strong volume (or multiple) scattering and depolarization effects over oyster reefs areas, whereas only surface scattering was dominant in most parts of the background tidal areas. In oyster reefs, the proportion of volume scattering and the cross-polarized ratio were greater than 0.7 and -8 dB, respectively. These scattering characteristics were also verified from in-situ measurements in the field using a ground-based polarimetric scatterometer system. However, almost no difference was observed between the scattering signatures of oyster reefs and background mudflat areas from L-band data, which have a considerably longer wavelength than C-band. The study clearly suggests that multi-frequency (C- and L-band) polarimetric SAR systems can be used to detect the naturally distributed oyster reefs in tidal flats.

  11. Improving management support tools for reintroducing bivalve species (eastern oyster [Crassostrea virginica Gmelin]) in urban estuaries.

    PubMed

    Ravit, Beth; Cooper, Keith; Buckley, Brian; Comi, Meredith; McCandlish, Elizabeth

    2014-10-01

    Successful reintroduction of "ecologically extinct" bivalve species into anthropogenically impaired urban estuaries is problematic when employing existing management tools used in estuaries where bivalves are present (GIS-based restoration models, expanding existing shellfish beds, placement of shell substrate, physical oceanographic parameters). A significant management challenge is appropriate site selection. We are proposing the inclusion of a biological parameter (evaluation of tissue histopathology) in an inexpensive and rapid site selection model to inform management decision making and identify sites with the greatest potential for reintroduction success. Use of biological biomarkers is not a new concept, but it is important that they be included in a multitiered management approach to bivalve reintroduction. This Case Study tested adult Eastern Oysters (Crassostrea virginica Gmelin) from locations that supported comparable short-term survival rates by evaluating growth and tissue health and/or disease. Biomarkers indicated oyster tissues at one site were normal, the female:male sex ratio was 50:50, and female oysters were in spawning condition. Conversely, oyster tissues at the second site exhibited multiple abnormalities, samples were 100% male, and the incidence of disease was high. Using the biomarker tool, we evaluated 4 additional sites where oysters exhibited short-term (1 year) survival. At 2 locations, we observed chronic health impacts that would preclude reintroduction, including samples from one site where a wild population was surviving. We also analyzed tissue and shell heavy metal contents. Soft tissue metal concentrations in Meadowlands samples were at the high range of scientific literature values, averaging 1.1% of total body weight, whereas tissue metal concentrations at the Keyport site were within acceptable ranges. Although initial survival and growth rates at both locations were comparable, site-specific urban stressors reduced oyster

  12. Invasive species cause large-scale loss of native California oyster habitat by disrupting trophic cascades.

    PubMed

    Kimbro, David L; Grosholz, Edwin D; Baukus, Adam J; Nesbitt, Nicholas J; Travis, Nicole M; Attoe, Sarikka; Coleman-Hulbert, Caitlin

    2009-06-01

    Although invasive species often resemble their native counterparts, differences in their foraging and anti-predator strategies may disrupt native food webs. In a California estuary, we showed that regions dominated by native crabs and native whelks have low mortality of native oysters (the basal prey), while regions dominated by invasive crabs and invasive whelks have high oyster mortality and are consequently losing a biologically diverse habitat. Using field experiments, we demonstrated that the invasive whelk's distribution is causally related to a large-scale pattern of oyster mortality. To determine whether predator-prey interactions between crabs (top predators) and whelks (intermediate consumers) indirectly control the pattern of oyster mortality, we manipulated the presence and invasion status of the intermediate and top trophic levels in laboratory mesocosms. Our results show that native crabs indirectly maintain a portion of the estuary's oyster habitat by both consuming native whelks (density-mediated trophic cascade) and altering their foraging behavior (trait-mediated trophic cascade). In contrast, invasive whelks are naive to crab predators and fail to avoid them, thereby inhibiting trait-mediated cascades and their invasion into areas with native crabs. Similarly, when native crabs are replaced with invasive crabs, the naive foraging strategy and smaller size of invasive crabs prevents them from efficiently consuming adult whelks, thereby inhibiting strong density-mediated cascades. Thus, while trophic cascades allow native crabs, whelks, and oysters to locally co-exist, the replacement of native crabs and whelks by functionally similar invasive species results in severe depletion of native oysters. As coastal systems become increasingly invaded, the mismatch of evolutionarily based strategies among predators and prey may lead to further losses of critical habitat that support marine biodiversity and ecosystem function.

  13. Warm temperature acclimation impacts metabolism of paralytic shellfish toxins from Alexandrium minutum in commercial oysters.

    PubMed

    Farrell, Hazel; Seebacher, Frank; O'Connor, Wayne; Zammit, Anthony; Harwood, D Tim; Murray, Shauna

    2015-09-01

    Species of Alexandrium produce potent neurotoxins termed paralytic shellfish toxins and are expanding their ranges worldwide, concurrent with increases in sea surface temperature. The metabolism of molluscs is temperature dependent, and increases in ocean temperature may influence both the abundance and distribution of Alexandrium and the dynamics of toxin uptake and depuration in shellfish. Here, we conducted a large-scale study of the effect of temperature on the uptake and depuration of paralytic shellfish toxins in three commercial oysters (Saccostrea glomerata and diploid and triploid Crassostrea gigas, n = 252 per species/ploidy level). Oysters were acclimated to two constant temperatures, reflecting current and predicted climate scenarios (22 and 27 °C), and fed a diet including the paralytic shellfish toxin-producing species Alexandrium minutum. While the oysters fed on A. minutum in similar quantities, concentrations of the toxin analogue GTX1,4 were significantly lower in warm-acclimated S. glomerata and diploid C. gigas after 12 days. Following exposure to A. minutum, toxicity of triploid C. gigas was not affected by temperature. Generally, detoxification rates were reduced in warm-acclimated oysters. The routine metabolism of the oysters was not affected by the toxins, but a significant effect was found at a cellular level in diploid C. gigas. The increasing incidences of Alexandrium blooms worldwide are a challenge for shellfish food safety regulation. Our findings indicate that rising ocean temperatures may reduce paralytic shellfish toxin accumulation in two of the three oyster types; however, they may persist for longer periods in oyster tissue.

  14. Physiological costs of reproduction in the Sydney rock oyster Saccostrea glomerata. How expensive is reproduction?

    PubMed

    Honkoop, P J C

    2003-04-01

    In this study, triploid Sydney rock oysters Saccostrea glomerata, which do not reproduce and have only limited gonadal development, were used to calculate the cost of producing and maintaining somatic tissues. The consumption of oxygen was measured and converted to units of energy expended. The consumption of oxygen of diploid oysters, in different stages of the reproductive cycle, was also measured. Knowing the costs of producing and maintaining somatic tissues (obtained from the triploid oysters), it was possible to calculate the energy demand of somatic and reproductive tissues of diploid oysters. The focus of this study was to test whether this method would work, to investigate if this method would give results in accordance with modern life-history theory and to test hypotheses about costs of reproduction in oysters. It was found that in diploid oysters, 27% of the consumed oxygen was needed for reproductive processes. It was also found that the costs of production and maintenance of reproductive tissues were on average 84% of those of somatic tissues. Costs for the production and maintenance of somatic tissues decreased over time. Costs for reproduction also decreased, but were dependent on the stage of gonadal development. If the relative mass of gametes in the gonads was large, the costs were relatively small; if the mass was relatively small, the costs were large. Differences between traits of males and females were never significant, suggesting that reproductive effort and costs were similar in males and females. It was estimated that if diploid oysters did not reproduce, they could gain 64% more somatic ash-free dry mass. Thus, in terms of growth, reproduction is an expensive activity.

  15. Rapid transcriptional acclimation following transgenerational exposure of oysters to ocean acidification.

    PubMed

    Goncalves, Priscila; Anderson, Kelli; Thompson, Emma L; Melwani, Aroon; Parker, Laura M; Ross, Pauline M; Raftos, David A

    2016-10-01

    Marine organisms need to adapt in order to cope with the adverse effects of ocean acidification and warming. Transgenerational exposure to CO2 stress has been shown to enhance resilience to ocean acidification in offspring from a number of species. However, the molecular basis underlying such adaptive responses is currently unknown. Here, we compared the transcriptional profiles of two genetically distinct oyster breeding lines following transgenerational exposure to elevated CO2 in order to explore the molecular basis of acclimation or adaptation to ocean acidification in these organisms. The expression of key target genes associated with antioxidant defence, metabolism and the cytoskeleton was assessed in oysters exposed to elevated CO2 over three consecutive generations. This set of target genes was chosen specifically to test whether altered responsiveness of intracellular stress mechanisms contributes to the differential acclimation of oyster populations to climate stressors. Transgenerational exposure to elevated CO2 resulted in changes to both basal and inducible expression of those key target genes (e.g. ecSOD, catalase and peroxiredoxin 6), particularly in oysters derived from the disease-resistant, fast-growing B2 line. Exposure to CO2 stress over consecutive generations produced opposite and less evident effects on transcription in a second population that was derived from wild-type (nonselected) oysters. The analysis of key target genes revealed that the acute responses of oysters to CO2 stress appear to be affected by population-specific genetic and/or phenotypic traits and by the CO2 conditions to which their parents had been exposed. This supports the contention that the capacity for heritable change in response to ocean acidification varies between oyster breeding lines and is mediated by parental conditioning.

  16. Detection and forecasting of oyster norovirus outbreaks: recent advances and future perspectives.

    PubMed

    Wang, Jiao; Deng, Zhiqiang

    2012-09-01

    Norovirus is a highly infectious pathogen that is commonly found in oysters growing in fecally contaminated waters. Norovirus outbreaks can cause the closure of oyster harvesting waters and acute gastroenteritis in humans associated with consumption of contaminated raw oysters. Extensive efforts and progresses have been made in detection and forecasting of oyster norovirus outbreaks over the past decades. The main objective of this paper is to provide a literature review of methods and techniques for detecting and forecasting oyster norovirus outbreaks and thereby to identify the future directions for improving the detection and forecasting of norovirus outbreaks. It is found that (1) norovirus outbreaks display strong seasonality with the outbreak peak occurring commonly in December-March in the U.S. and April-May in the Europe; (2) norovirus outbreaks are affected by multiple environmental factors, including but not limited to precipitation, temperature, solar radiation, wind, and salinity; (3) various modeling approaches may be employed to forecast norovirus outbreaks, including Bayesian models, regression models, Artificial Neural Networks, and process-based models; and (4) diverse techniques are available for near real-time detection of norovirus outbreaks, including multiplex PCR, seminested PCR, real-time PCR, quantitative PCR, and satellite remote sensing. The findings are important to the management of oyster growing waters and to future investigations into norovirus outbreaks. It is recommended that a combined approach of sensor-assisted real time monitoring and modeling-based forecasting should be utilized for an efficient and effective detection and forecasting of norovirus outbreaks caused by consumption of contaminated oysters.

  17. Construction and evaluation of a high-density SNP array for the Pacific oyster (Crassostrea gigas)

    PubMed Central

    Li, Chunyan; Wang, Wei; Li, Busu; Li, Li

    2017-01-01

    Single nucleotide polymorphisms (SNPs) are widely used in genetics and genomics research. The Pacific oyster (Crassostrea gigas) is an economically and ecologically important marine bivalve, and it possesses one of the highest levels of genomic DNA variation among animal species. Pacific oyster SNPs have been extensively investigated; however, the mechanisms by which these SNPs may be used in a high-throughput, transferable, and economical manner remain to be elucidated. Here, we constructed an oyster 190K SNP array using Affymetrix Axiom genotyping technology. We designed 190,420 SNPs on the chip; these SNPs were selected from 54 million SNPs identified through re-sequencing of 472 Pacific oysters collected in China, Japan, Korea, and Canada. Our genotyping results indicated that 133,984 (70.4%) SNPs were polymorphic and successfully converted on the chip. The SNPs were distributed evenly throughout the oyster genome, located in 3,595 scaffolds with a length of ~509.4 million; the average interval spacing was 4,210 bp. In addition, 111,158 SNPs were distributed in 21,050 coding genes, with an average of 5.3 SNPs per gene. In comparison with genotypes obtained through re-sequencing, ~69% of the converted SNPs had a concordance rate of >0.971; the mean concordance rate was 0.966. Evaluation based on genotypes of full-sib family individuals revealed that the average genotyping accuracy rate was 0.975. Carrying 133 K polymorphic SNPs, our oyster 190K SNP array is the first commercially available high-density SNP chip for mollusks, with the highest throughput. It represents a valuable tool for oyster genome-wide association studies, fine linkage mapping, and population genetics. PMID:28328985

  18. Post-mortem ecosystem engineering by oysters creates habitat for a rare marsh plant.

    PubMed

    Guo, Hongyu; Pennings, Steven C

    2012-11-01

    Oysters are ecosystem engineers in marine ecosystems, but the functions of oyster shell deposits in intertidal salt marshes are not well understood. The annual plant Suaeda linearis is associated with oyster shell deposits in Georgia salt marshes. We hypothesized that oyster shell deposits promoted the distribution of Suaeda linearis by engineering soil conditions unfavorable to dominant salt marsh plants of the region (the shrub Borrichia frutescens, the rush Juncus roemerianus, and the grass Spartina alterniflora). We tested this hypothesis using common garden pot experiments and field transplant experiments. Suaeda linearis thrived in Borrichia frutescens stands in the absence of neighbors, but was suppressed by Borrichia frutescens in the with-neighbor treatment, suggesting that Suaeda linearis was excluded from Borrichia frutescens stands by interspecific competition. Suaeda linearis plants all died in Juncus roemerianus and Spartina alterniflora stands, regardless of neighbor treatments, indicating that Suaeda linearis is excluded from these habitats by physical stress (likely water-logging). In contrast, Borrichia frutescens, Juncus roemerianus, and Spartina alterniflora all performed poorly in Suaeda linearis stands regardless of neighbor treatments, probably due to physical stresses such as low soil water content and low organic matter content. Thus, oyster shell deposits play an important ecosystem engineering role in influencing salt marsh plant communities by providing a unique niche for Suaeda linearis, which otherwise would be rare or absent in salt marshes in the southeastern US. Since the success of Suaeda linearis is linked to the success of oysters, efforts to protect and restore oyster reefs may also benefit salt marsh plant communities.

  19. Perkinsus marinus in pleasure oyster Crassostrea corteziensis from Nayarit, Pacific coast of México.

    PubMed

    Cáceres-Martínez, J; Vásquez-Yeomans, R; Padilla-Lardizábal, G; del Río Portilla, M A

    2008-09-01

    Culture of the pleasure oyster Crassostrea corteziensis is emerging as an alternative to the Pacific oyster (Crassostrea gigas) for oyster producers, who face severe mortalities since 1997 in Northwest México. For determining the health status of this species, we conducted a histopathological analysis of cultured populations from two estuaries in the Pacific coast of México. Macroscopical analysis revealed animals with transparent and retracted mantle. Histopathological analysis of these specimens showed tissue alterations and parasitic forms consistent with Perkinsus sp. infection. Stages of the parasite identified included tomont and trophozoites with an eccentric vacuole characteristic of Perkinsus spp. Pieces of tissues of infected oysters were incubated in Fluid Thioglycollate Medium (FTM) resulting in blue-black hypnospores after incubation. The identity of the parasite was confirmed by species specific PCR-based assay in DNA samples from oysters, tissue fractions from FTM cultures, and deparaffined samples with Perkinsus-like parasite detected by histology. Sequencing of positive amplified fragments (307bp) showed a sequence similar to Perkinsus marinus strain TXsc NTS ribosomal RNA gene (100% coverage and 98% identity, GenBank Accession No. AF497479.1) and to P. marinus, Genomic DNA, (100% coverage and 97% identity, GenBank Accession No. S78416.1). The prevalence of P. marinus varied from 1 to 5% in Boca del Camichín and from 1 to 6% in Pozo Chino. In general, the intensity of infection was moderate. The infection was observed in oysters from 31 to 110mm of shell length. This is the first record of P. marinus in oysters from the North America Pacific coast and the first record in C. corteziensis. The origin of this parasite in the area is unknown, but it may be associated to introductions of Crassostrea virginica from the East coast of United States of America or Gulf of México.

  20. Cadmium-dependent oxygen limitation affects temperature tolerance in eastern oysters (Crassostrea virginica Gmelin).

    PubMed

    Lannig, Gisela; Cherkasov, Anton S; Pörtner, Hans-O; Bock, Christian; Sokolova, Inna M

    2008-04-01

    Marine ectotherms, including oysters are exposed to variable environmental conditions in coastal shallow waters and estuaries. In the light of global climate change, additional stressors like pollution might pose higher risk to populations. On the basis of the concept of oxygen- and capacity-limited thermal tolerance in aquatic ectotherms (40), we show that a persistent pollutant, cadmium, can have detrimental effects on oysters (Crassostrea virginica). During acute warming from 20 to 28 degrees C (4 degrees C/48 h) standard metabolic rate (SMR) rose in control and cadmium-exposed (50 microg Cd2+/l) animals, with a consistently higher SMR in Cd-exposed oysters. Additionally, Cd-exposed oysters showed a stronger temperature-dependent decrease in hemolymph oxygen partial pressures. This observation indicates that the effect of temperature on aerobic metabolism was exacerbated due to the additional Cd stress. The oxygen delivery systems could not provide enough oxygen to cover Cd-induced elevated metabolic demands at high temperatures. Interestingly, cardiac performance (measured as the heart rate and hemolymph supply to tissues) rose to a similar extent in control and Cd-exposed oysters with warming indicating that cardiac output was unable to compensate for elevated energy demand in Cd-exposed oysters. Together with the literature data on metal-induced reduction of ventilatory capacity, these findings suggest that synergistic effects of elevated temperatures and cadmium exposure led to oxygen limitation by impaired performance in oxygen supply through ventilation and circulation. Overall, cadmium exposure resulted in progressive hypoxemia in oysters at high temperatures, suggesting that the thermal tolerance window is narrowed in marine ectotherms inhabiting polluted areas compared with pristine environments.

  1. Aneuploid progeny of the American oyster, Crassostrea virginica, produced by tetraploid × diploid crosses: another example of chromosome instability in polyploid oysters.

    PubMed

    de Sousa, Joana Teixeira; Allen, Standish K; Baker, Haley; Matt, Joseph L

    2016-05-01

    The commercial production of triploids, and the creation of tetraploid broodstock to support it, has become an important technique in aquaculture of the eastern oyster, Crassostrea virginica. Tetraploids are produced by cytogenetic manipulation of embryos and have been shown to undergo chromosome loss (to become a mosaic) with unknown consequences for breeding. Our objective was to determine the extent of aneuploidy in triploid progeny produced from both mosaic and non-mosaic tetraploids. Six families of triploids were produced using a single diploid female and crossed with three mosaic and non-mosaic tetraploid male oysters. A second set of crosses was performed with the reciprocals. Chromosome counts of the resultant embryos were tallied at 2-4 cell stage and as 6-hour(h)-old embryos. A significant level of aneuploidy was observed in 6-h-old embryos. For crosses using tetraploid males, aneuploidy ranged from 53% to 77% of observed metaphases, compared to 36% in the diploid control. For crosses using tetraploid females, 51%-71% of metaphases were aneuploidy versus 53% in the diploid control. We conclude that somatic chromosome loss may be a regular feature of early development in triploids, and perhaps polyploid oysters in general. Other aspects of chromosome loss in polyploid oysters are also discussed.

  2. Sensitivity of hepatitis A and murine norovirus to electron beam irradiation in oyster homogenates and whole oysters - quantifying the reduction in potential infection risks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite worldwide regulations and advisories restricting shellfish harvest to approved locations, consumption of raw oysters continues to be an exposure route for human norovirus (NoV) and hepatitis A virus (HAV). Therefore, a technology that can reduce the public health risks is needed. The focus...

  3. Comparison of haemocytic parameters among flat oyster Ostrea edulis stocks with different susceptibility to bonamiosis and the Pacific oyster Crassostrea gigas.

    PubMed

    Comesaña, Pilar; Casas, Sandra M; Cao, Asunción; Abollo, Elvira; Arzul, Isabelle; Morga, Benjamin; Villalba, Antonio

    2012-03-01

    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 explanation of the intra and interspecific differences in oyster susceptibility to bonamiosis was accomplished by comparing some immune parameters among various O. edulis stocks and C. gigas. On December 2003, naïve and Bonamia-relatively resistant flat oysters from Ireland, Galician flat oysters and Pacific oysters C. gigas were deployed in a Galician area affected by bonamiosis; haemolymph samples were taken in February and May 2004. A new oyster deployment at the same place was carried out on June 2004 and haemolymph sampling was performed on April 2005. On November 2004, new sets of Irish flat oysters and C. gigas were deployed in Ireland and haemolymph sampling was performed in June 2005. Various haemocytic parameters were measured: total and differential haemocyte count, phagocytic ability, respiratory burst (superoxide anion [O(2)(-)] and hydrogen peroxide [H(2)O(2)]) and nitric oxide [NO] production. The comparison of the parameters was carried out at 3 levels: (1) between O. edulis and C. gigas, (2) among O. edulis stocks with different susceptibility to bonamiosis, and (3) between Bonamia-infected and non infected O. edulis. In addition, haemocyte-B. ostreaein vitro encounters were performed to analyse interspecific differences in the haemocytic respiratory burst, using flow cytometry. Significant differences associated with total and differential haemocyte count, and respiratory burst between O. edulis and C. gigas were detected, which could be linked to differences in

  4. USE OF OYSTER HABITAT BY REEF-RESIDENT FISHES AND DECAPOD CRUSTACEANS IN THE CALOOSAHATCHEE ESTUARY, FLORIDA

    EPA Science Inventory

    Habitat suitability of oyster reefs for fishes and decapod crustaceans was examined monthly at three sites in the lower Caloosahatchee Estuary. At each site, 1-m2 lift nets containing approximately 5 liters (volume displacement) of oyster clumps were deployed for a period of two ...

  5. Multistate outbreak of viral gastroenteritis related to consumption of oysters--Louisiana, Maryland, Mississippi and North Carolina, 1993.

    PubMed

    1993-12-17

    On November 17, 1993, the state health departments of Louisiana, Maryland, and Mississippi notified CDC of several outbreaks of gastroenteritis occurring in their states since November 12. Preliminary epidemiologic investigations identified consumption of oysters as the primary risk factor for illness. On November 16, the Louisiana Department of Health and Hospitals (LDHH) had identified the Grand Pass and Cabbage Reef harvesting areas off the Louisiana coast as the source of oysters associated with outbreaks in Louisiana and Mississippi. Tagged oysters associated with outbreaks in Maryland were traced to the same oyster beds. The oysters harvested from these areas had been distributed throughout the United States. On November 18 and 19, the LDHH and CDC notified state epidemiologists of the potential for oyster-associated illness; outbreaks of oyster-associated gastroenteritis subsequently were identified in Florida and North Carolina. Collaborative investigations by state health officials, the Food and Drug Administration (FDA), and CDC were initiated to determine the magnitude and characteristics of the multistate outbreak, identify the etiologic agent, and trace the oysters. This report summarizes the preliminary findings of the ongoing investigation.

  6. INFLUENCE OF SALINITY ON HABITAT UTILIZATION OF OYSTER REEFS BY RESIDENT FISHES AND DECAPOD CRUSTACEANS IN THE CALOOSAHATCHEE ESTUARY, FLORIDA.

    EPA Science Inventory

    A spatiotemporal comparison of habitat suitability of oyster reefs for fishes and decapod crustaceans was conducted for the lower Caloosahatchee Estuary, Florida. Lift nets (1-m2) containing 5 liters (volume displacement) of oyster clusters were deployed monthly at three sites al...

  7. Oyster (Crassostrea gigas) hydrolysates produced on a plant scale have antitumor activity and immunostimulating effects in BALB/c mice.

    PubMed

    Wang, Yu-Kai; He, Hai-Lun; Wang, Guo-Fan; Wu, Hao; Zhou, Bai-Cheng; Chen, Xiu-Lan; Zhang, Yu-Zhong

    2010-02-02

    Oyster extracts have been reported to have many bioactive peptides. But the function of oyster peptides produced by proteolysis is still unknown. In this study, the oligopeptide-enriched hydrolysates from oyster (Crassostrea gigas) were produced using the protease from Bacillus sp. SM98011 at laboratory level, and scaled up to pilot (100 L) and plant (1,000 L) levels with the same conditions. And the antitumor activity and immunostimulating effects of the oyster hydrolysates in BALB/c mice were investigated. The growth of transplantable sarcoma-S180 was obviously inhibited in a dose-dependent manner in BALB/c mice given the oyster hydrolysates. Mice receiving 0.25, 0.5 and 1 mg/g of body weight by oral gavage had 6.8%, 30.6% and 48% less tumor growth, respectively. Concurrently, the weight coefficients of the thymus and the spleen, the activity of natural killer (NK) cells, the spleen proliferation of lymphocytes and the phagocytic rate of macrophages in S180-bearing mice significantly increased after administration of the oyster hydrolysates. These results demonstrated that oyster hydrolysates produced strong immunostimulating effects in mice, which might result in its antitumor activity. The antitumor and immunostimulating effects of oyster hydrolysates prepared in this study reveal its potential for tumor therapy and as a dietary supplement with immunostimulatory activity.

  8. 46 CFR 2.01-50 - Persons other than crew on towing, oyster, or fishing steam vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Persons other than crew on towing, oyster, or fishing steam vessels. 2.01-50 Section 2.01-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing,...

  9. Characterization of phenotypic variation for dermo resistance among selectively-bred families of the Eastern oyster, Crassostrea virginica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dermo disease impacts nearly every region where oysters are cultured in the Eastern U.S. and is a significant concern to industry stakeholders. Efforts to breed for Dermo resistance in the Eastern Oyster have had modest success, yet the range of existing phenotypic variation with respect to Dermo r...

  10. 46 CFR 2.01-50 - Persons other than crew on towing, oyster, or fishing steam vessels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Persons other than crew on towing, oyster, or fishing steam vessels. 2.01-50 Section 2.01-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing,...

  11. Perception of oyster-based products by French consumers. The effect of processing and role of social representations.

    PubMed

    Debucquet, Gervaise; Cornet, Josiane; Adam, Isabelle; Cardinal, Mireille

    2012-12-01

    The search for new markets in the seafood sector, associated with the question of the continuity of raw oyster consumption over generations can be an opportunity for processors to extend their ranges with oyster-based products. The twofold aim of this study was to evaluate the impact of processing and social representation on perception of oyster-based products by French consumers and to identify the best means of development in order to avoid possible failure in the market. Five products with different degrees of processing (cooked oysters in a half-shell, hot preparation for toast, potted oyster, oyster butter and oyster-based soup) were presented within focus groups and consumer tests, at home and in canteens with the staff of several companies in order to reach consumers with different ages and professional activities. The results showed that social representation had a strong impact and that behaviours were contrasted according to the initial profile of the consumer (traditional raw oyster consumers or non-consumers) and their age distribution (younger and older people). The degree of processing has to be adapted to each segment. It is suggested to develop early exposure to influence the food choices and preferences of the youngest consumers on a long-term basis.

  12. Assessing the extent of phenotypic variation for dermo resistance among selectively-bred families of the Eastern Oyster, Crassostrea virginica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dermo disease impacts nearly every region where oysters are cultured in the Eastern U.S. and is a significant concern to industry stakeholders. Efforts to breed for Dermo resistance in the Eastern Oyster have had modest success, yet the range of existing phenotypic variation with respect to Dermo ...

  13. 46 CFR 2.01-50 - Persons other than crew on towing, oyster, or fishing steam vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Persons other than crew on towing, oyster, or fishing steam vessels. 2.01-50 Section 2.01-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing,...

  14. PROGRESSION OF DISEASES CAUSED BY THE OYSTER PARASITES, PERKINSUS MARINUS AND HAPLOSPORIDIUM NELSONI, IN CRASSOSTREA VIRGINICA ON CONSTRUCTED INTERTIDAL REEFS

    EPA Science Inventory

    The progression of diseases caused by the oyster parasites, Perkinsus marinus and Haplosporidium nelsoni, were evaluated by periodic sampling (May 1994-Dec. 1995) of oysters, Crassostrea virginica, that set on an artificial reef located in the Piankatank River, Virginia, in Augus...

  15. Top-down control of phytoplankton by oysters in Chesapeake Bay, USA: Comment on Pomeroy et al. (2006)

    EPA Science Inventory

    Pomeroy et al. (2006) proposed that temporal and spatial mismatches between eastern oyster filtration and phytoplankton abundance will preclude restored stocks of eastern oysters from reducing the severity of hypoxia in the deep channel of central Chesapeake Bay. We refute this c...

  16. 46 CFR 2.01-50 - Persons other than crew on towing, oyster, or fishing steam vessels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Persons other than crew on towing, oyster, or fishing steam vessels. 2.01-50 Section 2.01-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing,...

  17. 46 CFR 2.01-50 - Persons other than crew on towing, oyster, or fishing steam vessels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Persons other than crew on towing, oyster, or fishing steam vessels. 2.01-50 Section 2.01-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing,...

  18. SURVEY OF OYSTERS CRASSOSTREA VIRGINICA FROM TAMPA BAY, FLORIDA: ASSOCIATIONS OF INTERNAL DEFENSE MEASUREMENTS WITH CONTAMINANT BURDENS

    EPA Science Inventory

    Oysters from 16 sites in Tampa Bay, Florida, were collected during a 6-week period in winter 1993 and analyzed for both biological characteristics and tissue chemical concentrations. Using previous sediment contamination and toxicity data, oyster tissues from the selected sites w...

  19. Apparent loss of Vibrio vulnificus from North Carolina oysters coincides with a drought-induced increase in salinity.

    PubMed

    Froelich, Brett A; Williams, Tiffany C; Noble, Rachel T; Oliver, James D

    2012-06-01

    Despite years of successful isolation of Vibrio vulnificus from estuarine waters, beginning in 2007, it was extremely difficult to culture V. vulnificus from either North Carolina estuarine water or oyster samples. After employing culture-based methods as well as PCR and quantitative PCR for the detection of V. vulnificus, always with negative results, we concluded that this pathogen had become nearly undetectable in the North Carolina estuarine ecosystem. We ensured that the techniques were sound by seeding North Carolina oysters with V. vulnificus and performing the same tests as those previously conducted on unadulterated oysters. V. vulnificus was readily detected in the seeded oysters using both classes of methods. Furthermore, oysters were obtained from the Gulf of Mexico, and V. vulnificus was easily isolated, confirming that the methodology was sound but that the oysters and waters of North Carolina were lacking the V. vulnificus population studied for decades. Strikingly, the apparent loss of detectable V. vulnificus coincided with the most severe drought in the history of North Carolina. The drought continued until the end of 2009, with an elevated water column salinity being observed throughout this period and with V. vulnificus being nearly nonexistent. When salinities returned to normal after the drought abated in 2010, we were again able to routinely isolate V. vulnificus from the water column, although we were still unable to culture it from oysters. We suggest that the oysters were colonized with a more salt-tolerant bacterium during the drought, which displaced V. vulnificus and may be preventing recolonization.

  20. Combined effects of temperature acclimation and cadmium exposure on mitochondrial function in eastern oysters Crassostrea virginica gmelin (Bivalvia: Ostreidae).

    PubMed

    Cherkasov, Anton S; Ringwood, Amy H; Sokolova, Inna M

    2006-09-01

    Cadmium and temperature have strong impacts on the metabolic physiology of aquatic organisms. To analyze the combined impact of these two stressors on aerobic capacity, effects of Cd exposure (50 microg/L) on mitochondrial function were studied in oysters (Crassostrea virginica) acclimated to 12 and 20 degrees C in winter and to 20 and 28 degrees C in fall. Cadmium exposure had different effects on mitochondrial bioenergetics of oysters depending on the acclimation temperature. In oysters acclimated to 12 degrees C, Cd exposure resulted in elevated intrinsic rates of mitochondrial oxidation, whereas at 28 degrees C, a rapid and pronounced decrease of mitochondrial oxidative capacity was found in Cd-exposed oysters. At the intermediate acclimation temperature (20 degrees C), effects of Cd exposure on intrinsic rates of mitochondrial oxidation were negligible. Degree of coupling significantly decreased in mitochondria from 28 degrees C-acclimated oysters but not in that from 12 degrees C- or 20 degrees C-acclimated oysters. Acclimation at elevated temperatures also increased sensitivity of oyster mitochondria to extramitochondrial Cd. Variation in mitochondrial membrane potential explained 41% of the observed variation in mitochondrial adenosine triphosphate synthesis and proton leak between different acclimation groups of oysters. Temperature-dependent sensitivity of metabolic physiology to Cd has significant implications for toxicity testing and for extrapolation of laboratory studies to field populations of aquatic poikilotherms, indicating the importance of taking into account the thermal regime of the environment.

  1. 33 CFR 165.552 - Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey. 165.552 Section 165.552 Navigation and Navigable... Coast Guard District § 165.552 Security Zone; Oyster Creek Generation Station, Forked River,...

  2. 33 CFR 165.552 - Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey. 165.552 Section 165.552 Navigation and Navigable... Coast Guard District § 165.552 Security Zone; Oyster Creek Generation Station, Forked River,...

  3. 33 CFR 165.552 - Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey. 165.552 Section 165.552 Navigation and Navigable... Coast Guard District § 165.552 Security Zone; Oyster Creek Generation Station, Forked River,...

  4. The Effects of Temperature and Nutritional Conditions on Mycelium Growth of Two Oyster Mushrooms (Pleurotus ostreatus and Pleurotus cystidiosus)

    PubMed Central

    Hoa, Ha Thi

    2015-01-01

    The influences of temperature and nutritional conditions on the mycelium growth of oyster mushroom Pleurotus ostreatus (PO) and Pleurotus cystidiosus (PC) were investigated in laboratory experiment during the summer season of 2014. The results of the experiment indicated that potato dextrose agar (PDA) and yam dextrose agar (YDA) were the most suitable media for the mycelium growth of oyster mushroom PO while four media (PDA, YDA, sweet potato dextrose agar, and malt extract agar medium) were not significantly different in supporting mycelium growth of oyster mushroom PC. The optimal temperature for mycelium growth of both oyster mushroom species was obtained at 28℃. Mycelium growth of oyster mushroom PO was improved by carbon sources such as glucose, molasses, and at 1~5% sucrose concentration, mycelium colony diameter of mushroom PO was achieved the highest value. Whereas glucose, dextrose, and sucrose as carbon sources gave the good mycelium growth of oyster mushroom PC, and at 1~3% sucrose concentration, mycelium colony diameter of PC was achieved the maximum value. Ammonium chloride concentrations at 0.03~0.09% and 0.03~0.05% also gave the greatest values in mycelium colony diameter of mushroom PO and PC. Brown rice was found to be the most favourable for mycelium growth of two oyster mushroom species. In addition, sugarcane residue, acasia sawdust and corn cob were selected as favourable lignocellulosic substrate sources for mycelium growth of both oyster mushrooms. PMID:25892910

  5. The performance of oyster families exposed to Dermo disease is contingent on the source of pathogen exposure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Here we report preliminary results from a course of research integrating pathology, feeding ecology, genetics and genomics to address resistance to Dermo disease in eastern oysters. We challenged six oyster families with Perkinsus marinus, the etiological agent of Dermo disease, through either direc...

  6. Radiation resistances and decontamination of common pathogenic bacteria contaminated in white scar oyster ( Crassostrea belcheri) in Thailand

    NASA Astrophysics Data System (ADS)

    Thupila, Nunticha; Ratana-arporn, Pattama; Wilaipun, Pongtep

    2011-07-01

    In Thailand, white scar oyster ( Crassostrea belcheri) was ranked for premium quality, being most expensive and of high demand. This oyster is often eaten raw, hence it may pose health hazards to consumers when contaminated with food-borne pathogens. As limited alternative methods are available to sterilize the oyster while preserving the raw characteristic, irradiation may be considered as an effective method for decontamination. In this study, the radiation resistance of pathogenic bacteria commonly contaminating the oyster and the optimum irradiation doses for sterilization of the most radiation resistant bacteria were investigated. The radiation decimal reduction doses ( D10) of Salmonella Weltevreden DMST 33380, Vibrio parahaemolyticus ATCC 17802 and Vibrio vulnificus DMST 5852 were determined in broth culture and inoculated oyster homogenate. The D10 values of S. Weltevreden, V. parahaemolyticus and V. vulnificus in broth culture were 0.154, 0.132 and 0.059 kGy, while those of inoculated oyster homogenate were 0.330, 0.159 and 0.140 kGy, respectively. It was found that among the pathogens tested, S. Weltevreden was proved to be the most resistant species. An irradiation dose of 1.5 kGy reduced the counts of 10 5 CFU/g S. Weltevreden inoculated in oyster meat to an undetectable level. The present study indicated that a low-dose irradiation can improve the microbial quality of oyster and further reduce the risks from the food-borne pathogens without adversely affecting the sensory attributes.

  7. The Effects of Temperature and Nutritional Conditions on Mycelium Growth of Two Oyster Mushrooms (Pleurotus ostreatus and Pleurotus cystidiosus).

    PubMed

    Hoa, Ha Thi; Wang, Chun-Li

    2015-03-01

    The influences of temperature and nutritional conditions on the mycelium growth of oyster mushroom Pleurotus ostreatus (PO) and Pleurotus cystidiosus (PC) were investigated in laboratory experiment during the summer season of 2014. The results of the experiment indicated that potato dextrose agar (PDA) and yam dextrose agar (YDA) were the most suitable media for the mycelium growth of oyster mushroom PO while four media (PDA, YDA, sweet potato dextrose agar, and malt extract agar medium) were not significantly different in supporting mycelium growth of oyster mushroom PC. The optimal temperature for mycelium growth of both oyster mushroom species was obtained at 28℃. Mycelium growth of oyster mushroom PO was improved by carbon sources such as glucose, molasses, and at 1~5% sucrose concentration, mycelium colony diameter of mushroom PO was achieved the highest value. Whereas glucose, dextrose, and sucrose as carbon sources gave the good mycelium growth of oyster mushroom PC, and at 1~3% sucrose concentration, mycelium colony diameter of PC was achieved the maximum value. Ammonium chloride concentrations at 0.03~0.09% and 0.03~0.05% also gave the greatest values in mycelium colony diameter of mushroom PO and PC. Brown rice was found to be the most favourable for mycelium growth of two oyster mushroom species. In addition, sugarcane residue, acasia sawdust and corn cob were selected as favourable lignocellulosic substrate sources for mycelium growth of both oyster mushrooms.

  8. 33 CFR 165.552 - Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey. 165.552 Section 165.552 Navigation and Navigable... Coast Guard District § 165.552 Security Zone; Oyster Creek Generation Station, Forked River,...

  9. 33 CFR 165.552 - Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey. 165.552 Section 165.552 Navigation and Navigable... Coast Guard District § 165.552 Security Zone; Oyster Creek Generation Station, Forked River,...

  10. ROLE OF ANTHROPOGENIC AND ENVIRONMENTAL VARIABLE ON THE PHYSIOLOGICAL AND ECOLOGICAL RESPONSES OF OYSTERS IN SOUTHWEST FLORIDA ESTUARIES

    EPA Science Inventory

    The role of freshwater alterations and seasonal changes on the ecological and physiological responses of oysters were investigated in the Caloosahatchee River, Estero Bay and Faka-Union estuaries in SW Florida. Condition index, oyster density, and disease incidence of Perkinsus m...

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

    PubMed Central

    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

  12. High pressure treatment changes spoilage characteristics and shelf life of Pacific oysters ( Crassostrea gigas) during refrigerated storage

    NASA Astrophysics Data System (ADS)

    Cao, Rong; Zhao, Ling; Liu, Qi

    2017-04-01

    The effects of high pressure (HP) treatment on spoilage characteristic and shelf life extension of Pacific oysters ( Crassostrea gigas) during refrigerated storage were studied. Results showed that HP treatment of 275 MPa for 3 min or 300 MPa for 2 min could achieve 100% full release of oyster adductor muscle, pressures higher than 350 MPa caused excessive release as the shells of oysters were broken, thus use of higher pressures should be cautious in oyster processing industry because of its adverse impact on the appearance of shells. HP treatment (300 MPa, 2 min) was proper for the shucking of Pacific oyster ( Crassostrea gigas) in China. This treatment caused no organoleptic disadvantage. Moreover, HP treatment resulted in obvious differences in biochemical spoilage indicators (pH, TVB-N and TBARS) changes and volatile compounds profile determined by electronic nose during storage. HP treatment (300 MPa, 2 min) also led to a reduction of aerobic bacterial count (APC) by 1.27 log cycles. Furthermore, the APC values of oysters treated by HP were always lower than those of the control samples during storage. Based on the organoleptic, biochemical and microbiological indicators, shelf life of 6-8 d for control and 12 d for HP-treated oysters could be expected. HP treatment showed great potential in oyster processing and preservation.

  13. Epizootic and enzootic aspects of Minchinia nelsoni (Haplosporida) disease in Maryland oysters.

    PubMed

    Farley, C A

    1975-08-01

    Minichinia nelsoni disease in oysters (Crassostrea virginica) from Marumsco Bar, Pocomoke Sound, Maryland (an estuarine tributary of Chesapeake Bay) was studied for 8 years (1961-68) to determine epizootiologic relationships concerning life cycle of the parasite, pathologic effects on the host, and effects of physical factors on population density and recruitment of the host and parasite. The study period covered pre-epizootic, epizootic, and post-epizootic disease conditions. Data on the native oyster population as well as annual introductions of previously unexposed, susceptible populations of juvenile oysters from 1965-68 were included. Salinity, water temperature, mortality, prevalence, incidence, life cycle stages, gross pathology, and histopathologic relationships were observed. Mortality was high (45-55% per year) during the first 3 years of the study; however, M. nelsoni prevalences were low (less than 25%) and did not clearly imply a cause and effect relationship. Drought conditions that began in the summer of 1963 and continued through 1967 caused higher salinities, and apparently initiated epizootic disease in the native oyster populations. The epizootic peaked in May 1965 with a diagnosed prevalence in native oysters of 70%. Enzootic levels of annual mortality (40% in 1966, 30% in 1967, and 2% in 1968) and fall prevalence (16%, 24%, and 4%) developed after that time. Introduced populations had a typical epizootiologic pattern in 1965 55% annual mortality, 82% incidence) and 1966 (55% annual mortality, 66% incidence) which declined in 1967 (30% annual mortality, 44% incidence) followed by a disappearance of the disease in 1968. Epizootiologic differences noted between native oysters (adult and juvenile) and the introduced juvenile populations were also evident from the stages of the disease. Infections in native animals tended to be less serious, and in many cases were delayed or attentuated, while infections in introduced oysters progressed to advanced

  14. Mortality and herpesvirus infections of the Pacific oyster Crassostrea gigas in Tomales Bay, California, USA.

    PubMed

    Burge, Colleen A; Griffin, Frederick J; Friedman, Carolyn S

    2006-09-14

    Seed losses of Pacific oysters Crassostrea gigas have been associated with an ostreid herpesvirus-1 (OsHV-1) in Europe, and in 2002, a similar OsHV was detected in Tomales Bay, California, USA. In May of 2003, 5 stocks of seed Pacific oysters were planted at 2 sites (Inner Bay and Outer Bay) in Tomales Bay and monitored for mortality, presence/prevalence of OsHV (using polymerase chain reaction [PCR] and histology), and growth. Temperature (degrees C) and salinity data were collected every half an hour at each site. OsHV was detected at both the Inner and Outer Bay sites on the same sample date and mean temperature predicted OsHV presence (p < 0.005). High levels of mortality occurred 2 wk (Inner Bay site) and 4 wk (Outer Bay site) after OsHV detection. OsHV presence predicted mortality (p = 0.01). Temperature maximums and overall temperature exposure were greater at the Inner Bay site and may explain why mortality affected these oysters sooner than oysters planted at the Outer Bay site. Differences in cumulative mortality were significant among stocks (p < 0.0001), but not between sites (p > 0.05). OsHV prevalence was similar among stocks (p > 0.05) and between sites (p > 0.05). No evidence of herpesvirus-induced Cowdry type A nuclear inclusions or other pathogens were observed. Changes in tissue and cellular architecture including dilation of the digestive tubules and nuclear chromatin margination and pycnosis were observed in OsHV-infected oysters, consistent with previously observed OsHV infections. Stocks with smaller oysters had higher mortality rates than those with larger oysters; growth rate did not correlate with mortalities (p > 0.05). Taken together, these data suggest that the OsHV may cause or act in synergy with temperature to kill Pacific oyster seed in Tomales Bay, but further investigation of OsHV etiology in seed oysters is needed.

  15. Unusually high intake and fecal output of cadmium, and fecal output of other trace elements in New Zealand adults consuming dredge oysters. [Tiostrea lutaria

    SciTech Connect

    McKenzie-Parnell, J.M.; Kjellstrom, T.E.; Sharma, R.P.; Robinson, M.F.

    1988-06-01

    The concentration of cadmium in New Zealand dredge oyster Tiostrea lutaria (commonly known as a Bluff oyster) is sufficiently high so that the ingestion of just one oyster can more than double a normal daily intake of cadmium for a New Zealand adult. A survey of 75 adults associated with the oyster fishing industry was carried out before and at the end of the oyster season. Preseason intakes (from dietary history questionnaires and from 3-day fecal collections) of cadmium, selenium, zinc, copper, and manganese were normal for a New Zealand adult not consuming Bluff oysters. The subjects were classified according to their reported average oyster consumption during the 6 months of the oyster fishing season; the subjects who consumed more oysters were more likely to smoke cigarettes. The end-season fecal output of cadmium confirmed the reported average oyster intakes: Category I (0-5 oysters/week): 15 +/- 8 (mean +/- SD) ..mu..g Cd/day; Category II (6-23 oysters/week): 84 +/- 134 ..mu..g Cd/day; Category III (24-71 oysters/week): 129 +/- 144 ..mu..g Cd/day; Category IV (72 + oysters/week): 233 +/- 185 ..mu..g Cd/day. The fecal output of selenium as well was increased by the consumption of many oysters but the fecal outputs of zinc, copper, manganese were not. Using fecal cadmium excretion to predict dietary cadmium intake, 8-15% of the subjects in this study were identified as having an intake of cadmium which has been associated with an increased prevalence of tubular proteinuria.

  16. Historical oyster reef connections to Chesapeake Bay - a framework for consideration

    NASA Astrophysics Data System (ADS)

    McCormick-Ray, Jerry

    2005-07-01

    Lieutenant Francis Winslow's 1878 oyster survey data of the lower Chesapeake Bay provided the spatial context for considering connectivities of Crassostrea virginica to estuarine function and food web dynamics. Winslow measured the area, water depths, and in some cases bed thickness for 70 distinct oyster beds in the 368 km 2 Tangier-Pocomoke complex, and 12 beds in 35 km 2 of the James River oyster reef habitat. Individual beds showed great size variations, yet most were <2 km 2. Beds occupied variable water depths, but most occurred in 1-4 m depths near shore and 2-12 m depths along channels. Varied bed-top topography and elevation changes created complex structures and hydrologic corridors between shores and tributaries. This historical spatial data provide a framework for considering oyster beds in the context of modern research to suggest they formed resource patches in the seascape at the estuarine scale. It is suggested that beds at different locations are connected by hydrologic corridors, and they facilitate dispersion, migration, and recruitment. Also, oyster-reef habitat added topographic roughness and spatial heterogeneity that increase resource-use options important to an active and diverse estuarine community moving between shore and tributary systems, and between Bay waters and watershed systems.

  17. Examining Relationships Among Several Oyster Pathogens in the Genus Bonamia Using Molecular Data, in Phylogenetic Analyses

    NASA Astrophysics Data System (ADS)

    White, D.; Burreson, E.

    2006-12-01

    Bonamiasis is a disease that affects oyster stocks around the world and is caused by intracellular protozoan parasites. Bonamia species can rapidly spread through oyster stocks and cause clinical disease in the host. The type species in the genus, Bonamia ostreae, was described from the European flat oyster Ostrea edulis. Since that time, several bonamia-like species have been observed in the following oyster hosts: Crassostrea ariakensis deployed in North Carolina, USA, Ostrea pulchana from Argentina, Ostrea chilensis from Chile, and in Ostrea angasi from Australia. There is, however, much debate over the species identity of these undescribed Bonamia parasites. An hypothesis that I will test is whether the species of Bonamia that occurs in the aforementioned oysters are representative of one species of Bonamia, Bonamia exitiosa, or are representative of different, currently undescribed, species of Bonamia. To test this hypothesis, molecular techniques to include the polymerase chain reaction (PCR) and simultaneous bi-directional sequencing (SBS) reactions were utilized to target the internal transcribed spacer (ITS) region of the ribosomal RNA gene complex for each of the undescribed Bonamia species and for Bonamia exitiosa. Phylogenetic analysis of the sequenced data in addition to pertinent morphological data, geographic distribution information, and possible host dispersals are included in this study to provide additional information for testing hypotheses developed based on molecular data.

  18. Field studies using the oyster Crassostrea virginica to determine mercury accumulation and depuration rates

    SciTech Connect

    Palmer, S.J.; Presley, B.J.; Powell, E.N. ); Taylor, R.J. )

    1993-09-01

    Mercury as an environmental hazard, especially with regard to human health, has been of concern since the Minamata disaster. From 1966 to 1970 a chlor-alkali plant in Point Comfort, Texas released mercury-enriched wastewater (up to 29.9 kgHg/day) into Lavaca Bay (TWQB 1977). Since 1970 the Texas Department of Health (TDH) has periodically closed and then re-opened portions of Lavaca Bay to the harvesting of crabs and finfish based on their levels (<>0.5 ppm Hg wet weight) of mercury. A 1988 closure remains in effect as of this writing. Mercury contamination in Lavaca Bay organisms thus continues to be a problem 22 years after the chlor-alkali plant ceased releasing mercury into the bay. The goal of the following research was to better understand the behavior of mercury in Lavaca Bay. Oysters have been widely used as indicator species in metal pollution studies. Most such programs have focused on the concentrations of metals in oysters from different geographic areas. This study, however, investigated the rate and amount of mercury a [open quotes]clean[close quotes] oyster would accumulate when transplanted to a contaminated estuary and the rate of mercury depuration by contaminated oysters placed in a clean environment. The oysters were additionally analyzed for Ba, Cu, Fe, P, and Zn to test for the possible involvement of these metals in mercury accumulation and depuration. 17 refs., 3 figs., 2 tabs.

  19. Stimulation of lymphocyte proliferation by oyster glycogen sulfated at C-6 position.

    PubMed

    Yang, Jingfeng; Zhu, Beiwei; Zheng, Jie; Sun, Liming; Zhou, Dayong; Dong, Xiuping; Yu, Chenxu

    2013-04-15

    In this study, glycogen was extracted from oyster Ostrea talienwhanensis Crosse and used as a model to investigate the structure-activity correlation of polysaccharides. Purified oyster glycogen was characterized by methylation analysis, nuclear magnetic resonance (NMR) spectroscopy and infrared spectroscopy (IR). The oyster glycogen was subsequently sulfated by chlorosulfonic acid-pyridine method, and a C-6 substituted species (SOG) was identified to be the primary sulfated oyster glycogen species by (13)C NMR spectroscopy. The molecular weight and sulfate content of the SOG was determined to be 3.2×10(4) g/mol and 33.6%, respectively. Another sulfated oyster glycogen species (SOG1) with C-2 and C-3 substitution was also identified at a lesser amount in the final product. SOG exhibited a much stronger stimulation effect to splenic lymphocyte proliferation than SOG1 in vitro, indicating that the position of sulfate substitution is a major determining factor on the efficacy of sulfated glycogens to stimulate lymphocyte proliferation.

  20. Norovirus genotypes implicated in two oyster-related illness outbreaks in Ireland.

    PubMed

    Rajko-Nenow, P; Keaveney, S; Flannery, J; McINTYRE, A; Doré, W

    2014-10-01

    We investigated norovirus (NoV) concentrations and genotypes in oyster and faecal samples associated with two separate oyster-related outbreaks of gastroenteritis in Ireland. Quantitative analysis was performed using real-time quantitative reverse transcription polymerase chain reaction and phylogenetic analysis was conducted to establish the NoV genotypes present. For both outbreaks, the NoV concentration in oysters was >1000 genome copies/g digestive tissue and multiple genotypes were identified. In faecal samples, GII.13 was the only genotype detected for outbreak 1, whereas multiple genotypes were detected in outbreak 2 following the application of cloning procedures. While various genotypes were identified in oyster samples, not all were successful in causing infection in consumers. In outbreak 2 NoV GII.1 was identified in all four faecal samples analysed and NoV GII concentrations in faecal samples were >108 copies/g. This study demonstrates that a range of NoV genotypes can be present in highly contaminated oysters responsible for gastroenteritis outbreaks.

  1. Chronic or accidental exposure of oysters to norovirus: is there any difference in contamination?

    PubMed

    Ventrone, Iole; Schaeffer, Julien; Ollivier, Joanna; Parnaudeau, Sylvain; Pepe, Tiziana; Le Pendu, Jacques; Le Guyader, Françoise S

    2013-03-01

    Bivalve molluscan shellfish such as oysters may be contaminated by human pathogens. Currently, the primary pathogens associated with shellfish-related outbreaks are noroviruses. This study was conducted to improve understanding of oyster bioaccumulation when oysters were exposed to daily contamination or one accidental contamination event, i.e., different modes of contamination. Oysters were contaminated with two representative strains of norovirus (GI.1 and GII.3) and then analyzed with real-time reverse transcription PCR. Exposure to a repeated virus dose for 9 days (mimicking a growing area subjected to frequent sewage contamination) led to an additive accumulation that was not significantly different from that obtained when the same total dose of virus was added all at once (as may happen after accidental sewage discharge). Similarly, bioaccumulation tests performed with mixed strains revealed additive accumulation of both viruses. Depuration may not be efficient for eliminating viruses; therefore, to prevent contaminated shellfish from being put onto the market, continuous sanitary monitoring must be considered. All climatic events or sewage failures occurring in production areas must be recorded, because repeated low-dose exposure or abrupt events may lead to similar levels of accumulation. This study contributes to an understanding of norovirus accumulation in oysters and provides suggestions for risk management strategies.

  2. Epizootiology of diseases of oysters (Crassostrea virginica), and parasites of associated organisms in eastern North America

    NASA Astrophysics Data System (ADS)

    Andrews, J. D.

    1984-03-01

    Haplosporidan parasites of oysters have been reported from four continents. Those of the general Minchinia, Haplosporidium, and Marteilia, which cause serious diseases of oysters, have been intensively studied. Epizootiology of these highly pathogenic species is well known. Life cycles are obscure for all haplosporidans because artificial infections have not been achieved. The high pathogenicity of newly-discovered haplosporidan diseases to native oysters in eastern North America and western Europe may indicate that these are exotic pathogens parasitizing susceptible oysters not previously exposed to these disease agents. Epizootiology of two haplosporidan pathogens along the middle Atlantic Coast of North America during 25 years of disease activity is discussed. Haplosporidium nelsoni sporulates only rarely and its life cycle remains unconfirmed. Resistant oysters were developed in nature and from laboratory breeding. Haplosporidium costale which causes “Seaside Disease” in high-salinity waters appears to be a more acclimated disease with regular patterns of infection and mortality. Several minor parasites whose life cycles and host species need more study are mentioned.

  3. Ostreid herpesvirus in wild oysters from the Huelva coast (SW Spain).

    PubMed

    López-Sanmartín, M; López-Fernández, J R; Cunha, M E; De la Herrán, R; Navas, J I

    2016-08-09

    This is the first report of ostreid herpesvirus 1 microvariant (OsHV-1 µVar) infecting natural oyster beds located in Huelva (SW Spain). The virus was detected in 3 oyster species present in the intertidal zone: Crassostrea gigas (Thunberg, 1793), C. angulata (Lamarck, 1819) and, for the first time, in Ostrea stentina Payraudeau, 1826. Oysters were identified by a specific polymerase chain reaction (PCR) and posterior restriction fragment length polymorphism (RFLP) analysis based on cytochrome oxidase I (COI) mitochondrial DNA. Results confirmed that C. angulata still remains the dominant oyster population in SW Spain despite the introduction of C. gigas for cultivation in the late 1970s, and its subsequent naturalization. C. angulata shows a higher haplotype diversity than C. gigas. OsHV-1 virus was detected by PCR with C2/C6 pair primers. Posterior RFLP analyses with the restriction enzyme MfeI were done in order to reveal the OsHV-1 µVar. Detections were confirmed by DNA sequencing, and infections were evidenced by in situ hybridization in C. gigas, C. angulata and O. stentina samples. The prevalence was similar among the 3 oyster species but varied between sampling locations, being higher in areas with greater harvesting activities. OsHV-1 µVar accounted for 93% of all OsHV-1 detected.

  4. Concentrations of polychlorinated biphenyl congeners in cultivated oysters (Crassostrea gigas) in western Taiwan.

    PubMed

    Fang, M D; Fang, H-T; Lee, C-L; Ko, F-C; Baker, J E

    2006-08-01

    Spatial and temporal variations of polychlorinated biphenyl (PCB) concentrations in cultivated oysters from five aquaculture areas along the western coast of Taiwan were investigated. Poor correlations between total PCB concentrations (ng/g dry weight [dw]) and physiologic parameters of oysters (shell length, width, thickness, and lipid content) were found. Total PCB concentrations ranged from 3.4 to 94 cng/g dw. The highest value was found in oysters from the Lu'ermen aquaculture area, which receives wastewater from a sodium hydroxide and pentachlorophenol factory. Furthermore, principal component analysis confirmed that the PCB congener pattern in this area was distinct from others and that two additional pollution sources might exist in the Tainan and Hsinchu areas. Oysters with PCB concentrations > 1 SD above the geometric mean were found mainly in Tainan (stations TN5 to TN9) with only one increased concentration in the Yunlin (station YL2) and Hsinchu (station HC4) aquaculture areas. Except for four confined stations, TN3 to TN6, where total PCB concentrations were higher (p = 0.028) in the warmer (May and July) than in the colder season (November and March), seasonal variation of total PCB concentrations in oysters was not significant. Geometric mean and geometric mean plus 1 SD of total PCB concentrations in this study are lower than those in South Korea and the United States (Mussel Watch).

  5. The ecology of intertidal oyster reefs of the South Atlantic Coast: A community profile

    USGS Publications Warehouse

    Bahr, Leonard M.; Lanier, William P.

    1981-01-01

    The functional role of the intertidal oyster reef community in the southeastern Atlantic coastal zone is described. This description is based on a compilation of published data, as well as some unpublished information presented as hypotheses. The profile is organized in a hierarchical manner, such that relevant details of reef oyster biology (autecology) are presented, followed by a description of the reef community level of organization. Then the reef community is described as a subsystem of the coastal marsh-ecosystem (synecoloqy). This information is also synthesized in a series of nested conceptual models of oyster reefs at the regional level, the drainage basin level, and the individual reef level. The final chapter includes a summary overview and a section on management implications and guidelines. Intertidal oyster reefs are relatively persistent features of the salt marsh estuarine ecosystem in the southeastern Atlantic coastal zone. The average areal extent of the oyster reef subsystem in this larger ecosystem is relatively small (about 0.05%). This proportion does not reflect, however, the functional importance of the reef subsystem in stablizing the marsh, providing food for estuarine consumers, mineralizing organic matter, and providing firm substrates in this otherwise soft environment.

  6. Vibrio crassostreae, a benign oyster colonizer turned into a pathogen after plasmid acquisition.

    PubMed

    Bruto, Maxime; James, Adèle; Petton, Bruno; Labreuche, Yannick; Chenivesse, Sabine; Alunno-Bruscia, Marianne; Polz, Martin F; Le Roux, Frédérique

    2016-12-06

    Vibrios are frequently associated with oyster mortality; however whether they are the primary causative agent or secondary opportunistic colonizers is not well understood. Here we combine analysis of natural infection dynamics, population genomics and molecular genetics to ask (i) to what extent oysters are passively colonized by Vibrio population present in the surrounding water, (ii) how populations turn over during pathogenicity events and (iii) what genetic factors are responsible for pathogenicity. We identified several populations of Vibrio preferentially associated with oyster tissues. Among these, Vibrio crassostreae is particularly abundant in diseased animals while nearly absent in the surrounding water, and its pathogenicity is correlated with the presence of a large mobilizable plasmid. We further demonstrate that the plasmid is essential for killing but not necessary for survival in tissues of oysters. Our results suggest that V. crassostreae first differentiated into a benign oyster colonizer that was secondarily turned into a pathogen by introgression of a virulence plasmid into the population, possibly facilitated by elevated host density in farming areas.The ISME Journal advance online publication, 6 December 2016; doi:10.1038/ismej.2016.162.

  7. Testing the effect of habitat structure and complexity on nekton assemblages using experimental oyster reefs

    USGS Publications Warehouse

    Humphries, Austin T.; LaPeyre, Megan K.; Kimball, Matthew E.; Rozas, Lawrence P.

    2011-01-01

    Structurally complex habitats are often associated with more diverse and abundant species assemblages in both aquatic and terrestrial ecosystems. Biogenic reefs formed by the eastern oyster (Crassostrea virginica) are complex in nature and are recognized for their potential habitat value in estuarine systems along the US Atlantic and Gulf of Mexico coasts. Few studies, however, have examined the response of nekton to structural complexity within oyster reefs. We used a quantitative sampling technique to examine how the presence and complexity of experimental oyster reefs influence the abundance, biomass, and distribution of nekton by sampling reefs 4 months and 16 months post-construction. Experimental oyster reefs were colonized immediately by resident fishes and decapod crustaceans, and reefs supported a distinct nekton assemblage compared to mud-bottom habitat. Neither increased reef complexity, nor age of the experimental reef resulted in further changes in nekton assemblages or increases in nekton abundance or diversity. The presence of oyster reefs per se was the most important factor determining nekton usage.

  8. Sequence analysis and quantitative detection of Norwalk-like viruses in cultured oysters of China

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Tang, Qingjuan; Yue, Zhiqin; Li, Zhaojie; Zhang, Jin; Xue, Changhu

    2008-05-01

    We isolated 4 Norwalk-like viruses (NLVs) contaminated oysters from 33 Chinese oysters collected from local commercial sources of Shandong Province. After amplification of the RNA-dependent RNA polymerase (RdRp) region of NLVs genomes with RT-PCR, the open reading frame 1 (ORF1) of the RdRp was sequenced and subjected to multiple-sequence alignment. The results showed that NLVs in the four isolates belong to genogroup II. The sequence comparison showed that the similarity between four Chinese oyster isolates were higher than 99.0%, which indicated that NLVs prevalent in close areas have high homogeneity in genome sequences. In addition, the most conserved sequences between diverse NLVs were used to design primers and TaqMan probes, then the real-time quantitative PCR assay was performed. According to the standard curve of GII NLVs, the original amounts (copies) of NLVs in positive patient’s fecal isolate, positive Japanese oyster isolate, and the Chinese oyster isolate were 8.9×108, 1.25×108 and 4.7×101 respectively. The detecting limit of NLVs was 1×101 copies. This study will be helpful for routine diagnosis of NLVs pathogens in foods and thus for avoiding food poisoning in the future.

  9. Oral bioaccessibility of toxic metals in contaminated oysters and relationships with metal internal sequestration.

    PubMed

    Gao, Shi; Wang, Wen-Xiong

    2014-12-01

    The Hong Kong oysters Crassostrea hongkongensis are widely farmed in the estuarine waters of Southern China, but they accumulate Cu and Zn to alarmingly high concentrations in the soft tissues. Health risks of seafood consumption are related to contaminants such as toxic metals which are bioaccessible to humans. In the present study, we investigated the oral bioaccessibility of five toxic metals (Ag, Pb, Cd, Cu and Zn) in contaminated oysters collected from different locations of a large estuary in southern China. In all oysters, total Zn concentration was the highest whereas total Pb concentration was the lowest. Among the five metals, Ag had the lowest oral bioaccessibility (38.9-60.8%), whereas Cu and Zn had the highest bioaccessibility (72.3-93.1%). Significant negative correlation was observed between metal bioaccessibility and metal concentration in the oysters for Ag, Cd, and Cu. We found that the oral bioaccessibility of the five metals was positively correlated with their trophically available metal fraction (TAM) in the oyster tissues, and negatively correlated with metal distribution in the cellular debris. Thus, metal partitioning in the TAM and cellular debris controlled the oral bioaccessibility to humans. Given the dependence of oral bioaccessibility on tissue metal contamination, bioaccessibility needs to be incorporated in the risk assessments of contaminated shellfish.

  10. Subcellular fractionation of Cu exposed oysters, Crassostrea virginica, and Cu accumulation from a biologically incorporated Cu rich oyster diet in Fundulus heteroclitus in fresh and sea water.

    PubMed

    Blanchard, Jonathan; Brix, Kevin; Grosell, Martin

    2009-05-01

    In order to examine the effect of salinity on Cu accumulation from a naturally incorporated diet, oysters (Crassostrea virginica) were exposed in sea water for 96 days to four waterborne [Cu]: 2.9+/-0.7 (control), 4.3+/-0.6, 5.4+/-0.5, and 10.7+/-1.0 microg L(-1). After 96 days, the control whole body [Cu] increased from 2.1+/-0.5 to 9.1+/-1.1 microg g(-1) w.w. and the highest [Cu] was 163.4+/-27.1 microg g(-1) w.w. in the oysters. Despite large differences in tissue [Cu], there was no effect on the fraction of trophically available metal in the oyster suggesting that trophic transfer will correlate well with tissue [Cu]. The control and highest [Cu] oysters became diet for killifish (Fundulus heteroclitus) in fresh and seawater for 40 days. The two diets contained 84.7+/-5.1 and 850.5+/-8.8 microg Cu g(-1) d.w. Fish were fed a combined diet of oyster and a pellet supplement (20.5+/-1.0 microg Cu g(-1) d.w.) both at 5% body mass day(-1). In killifish, Cu increased approximately 7% in gills and 100% in intestines after 6 weeks of exposure to the high Cu diet. No other tissues accumulated Cu above control levels. An 11-fold difference free Cu(2+) concentrations was predicted in intestinal fluid between fresh and sea water, but there was no corresponding effect of salinity on intestinal Cu accumulation suggesting that Cu is not accumulated as the free ion.

  11. Distribution of trace metals in the Pacific Oyster, Crassostrea gigas, and crabs from the east coast of Kyushu Island, Japan

    SciTech Connect

    Szefer, P.; Frelek, K.; Geldon, J.

    1997-01-01

    Oysters are known to be exceptional accumulators of Zn and Cu, and their tissue concentrations appear to reflect contamination of metals. According to Lauenstein and Dolvin, oysters clearly have a greater affinity for Ag, Cu and Zn than do mussels, while mussels have greater affinity for Cr and Pb. Oysters have been considered to be potential bioindicators for monitoring metallic pollution in marine environments. Extensive investigations of oysters from the east coast of Kyushu Island, Japan, have been performed. The aim of the study was to examine spatial differences in metal concentrations in soft tissues of the Pacific oyster (Crassostrea gigas) and whole bodies (soft tissues with shells) of the crabs Goetice depressa and Leptodius exaratus inhabiting the Japanese coastal region of the Pacific. 18 refs., 3 figs.

  12. Bioaccumulation of heavy metals in oysters from the southern coast of Korea: assessment of potential risk to human health.

    PubMed

    Mok, Jong Soo; Yoo, Hyun Duk; Kim, Poong Ho; Yoon, Ho Dong; Park, Young Cheol; Lee, Tae Seek; Kwon, Ji Young; Son, Kwang Tae; Lee, Hee Jung; Ha, Kwang Soo; Shim, Kil Bo; Kim, Ji Hoe

    2015-06-01

    From 2009 to 2013, 80 oyster and 16 seawater samples were collected from the southern coast of Korea, including designated shellfish growing areas for export. The concentrations and bioaccumulation of heavy metals were determined, and a potential risk assessment was conducted to evaluate their hazards towards human consumption. The cadmium (Cd) concentration in oysters was the highest of three hazardous metals, including Cd, lead (Pb), and mercury (Hg), however, below the standards set by various countries. The metal bioaccumulation ratio in oysters was relatively high for zinc and Cd but low for Hg, Pb, arsenic, and chromium. The estimated dietary intakes of all heavy metals for oysters accounted for 0.02%-17.75% of provisional tolerable daily intake. The hazard index for all samples was far <1.0, which indicates that the oysters do not pose an appreciable hazard to humans for the metal pollutants of study.

  13. Antibiotic resistance monitoring in heterotrophic bacteria from anthropogenic-polluted seawater and the intestines of oyster Crassostrea hongkongensis.

    PubMed

    Wang, Rui Xuan; Wang, AnLi; Wang, Jiang Yong

    2014-11-01

    A total of 1,050 strains of heterotrophic bacteria isolated from farming seawater and the intestines of oyster species Crassostrea hongkongensis were tested for resistance to 10 antibiotics by the Kirby-Bauer diffusion method. The resistant rates of seawater-derived bacteria to chloramphenicol, enrofloxacin, and ciprofloxacin were low (less than 20%), whereas the bacteria obtained from oysters showed low resistance to chloramphenicol and enrofloxacin. Many strains showed high resistant rates (more than 40%) to furazolidone, penicillin G, and rifampin. A total of 285 strains from farming seawater and oysters were resistant to more than three antibiotics. Several strains showed resistance to more than nine antibiotics. Furthermore, the peak resistant rates of the seawater-derived strains to multiple antibiotics overlapped in April, June, September, and November, and those of oyster-derived strains overlapped during April, July, and September. The multi-resistant rate patterns of strains from farming seawater and oyster intestines were similar.

  14. Expression, tissue localization and synergy of antimicrobial peptides and proteins in the immune response of the oyster Crassostrea gigas.

    PubMed

    Schmitt, Paulina; de Lorgeril, Julien; Gueguen, Yannick; Destoumieux-Garzón, Delphine; Bachère, Evelyne

    2012-07-01

    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-regulated in hemocytes upon infection. The migratory behavior of hemocytes that express the different antimicrobials was found to be involved in the oyster response to a pathogenic Vibrio infection. Indeed, it contributes to colocalize several antimicrobials that were shown here to have synergistic activities. We propose that such a synergy, which was evidenced both within and between families of antimicrobials, might compensate for the low concentration of antimicrobials in oyster tissues.

  15. Biomonitoring of trace metal contamination in the Potengi estuary, Natal (Brazil), using the oyster Crassostrea rhizophorae, a local food source.

    PubMed

    Silva, C A; Rainbow, P S; Smith, B D; Santos, Z L

    2001-12-01

    The oyster Crassostrea rhizophorae was collected in September 1997 from 10 stations along the Potengi estuary, Natal, Brazil, a mangrove-lined estuary receiving anthropogenic inputs of trace metals. C. rhizophorae is a net accumulator of trace metals and can be used as a biomonitor, the accumulated soft tissue concentrations representing integrated records of bioavailable metal fractions over the life of the oyster. Significant differences in oyster accumulated concentrations (and hence bioavailabilities) of Fe, Zn, Cu, Cr, Pb, Cd, Ni and Ag (but not Mn) were found between stations, and attributed to anthropogenic inputs including discharges of sewage and industrial effluent. The oysters are also a local food source, and concentrations of zinc, copper and lead in some of the oysters are above typical public health recommended limits.

  16. A restoration suitability index model for the eastern oyster (Crassostrea virginica) in the Mission-Aransas Estuary, TX, USA.

    PubMed

    Beseres Pollack, Jennifer; Cleveland, Andrew; Palmer, Terence A; Reisinger, Anthony S; Montagna, Paul A

    2012-01-01

    Oyster reefs are one of the most threatened marine habitats on earth, with habitat loss resulting from water quality degradation, coastal development, destructive fishing practices, overfishing, and storm impacts. For successful and sustainable oyster reef restoration efforts, it is necessary to choose sites that support long-term growth and survival of oysters. Selection of suitable sites is critically important as it can greatly influence mortality factors and may largely determine the ultimate success of the restoration project. The application of Geographic Information Systems (GIS) provides an effective methodology for identifying suitable sites for oyster reef restoration and removes much of the uncertainty involved in the sometimes trial and error selection process. This approach also provides an objective and quantitative tool for planning future oyster reef restoration efforts. The aim of this study was to develop a restoration suitability index model and reef quality index model to characterize locations based on their potential for successful reef restoration within the Mission-Aransas Estuary, Texas, USA. The restoration suitability index model focuses on salinity, temperature, turbidity, dissolved oxygen, and depth, while the reef quality index model focuses on abundance of live oysters, dead shell, and spat. Size-specific Perkinsus marinus infection levels were mapped to illustrate general disease trends. This application was effective in identifying suitable sites for oyster reef restoration, is flexible in its use, and provides a mechanism for considering alternative approaches. The end product is a practical decision-support tool that can be used by coastal resource managers to improve oyster restoration efforts. As oyster reef restoration activities continue at small and large-scales, site selection criteria are critical for assisting stakeholders and managers and for maximizing long-term sustainability of oyster resources.

  17. A Restoration Suitability Index Model for the Eastern Oyster (Crassostrea virginica) in the Mission-Aransas Estuary, TX, USA

    PubMed Central

    Beseres Pollack, Jennifer; Cleveland, Andrew; Palmer, Terence A.; Reisinger, Anthony S.; Montagna, Paul A.

    2012-01-01

    Oyster reefs are one of the most threatened marine habitats on earth, with habitat loss resulting from water quality degradation, coastal development, destructive fishing practices, overfishing, and storm impacts. For successful and sustainable oyster reef restoration efforts, it is necessary to choose sites that support long-term growth and survival of oysters. Selection of suitable sites is critically important as it can greatly influence mortality factors and may largely determine the ultimate success of the restoration project. The application of Geographic Information Systems (GIS) provides an effective methodology for identifying suitable sites for oyster reef restoration and removes much of the uncertainty involved in the sometimes trial and error selection process. This approach also provides an objective and quantitative tool for planning future oyster reef restoration efforts. The aim of this study was to develop a restoration suitability index model and reef quality index model to characterize locations based on their potential for successful reef restoration within the Mission-Aransas Estuary, Texas, USA. The restoration suitability index model focuses on salinity, temperature, turbidity, dissolved oxygen, and depth, while the reef quality index model focuses on abundance of live oysters, dead shell, and spat. Size-specific Perkinsus marinus infection levels were mapped to illustrate general disease trends. This application was effective in identifying suitable sites for oyster reef restoration, is flexible in its use, and provides a mechanism for considering alternative approaches. The end product is a practical decision-support tool that can be used by coastal resource managers to improve oyster restoration efforts. As oyster reef restoration activities continue at small and large-scales, site selection criteria are critical for assisting stakeholders and managers and for maximizing long-term sustainability of oyster resources. PMID:22792410

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

    PubMed

    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

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

    PubMed

    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.

  20. Effects of flash freezing, followed by frozen storage, on reducing Vibrio parahaemolyticus in Pacific raw oysters (Crassostrea gigas).

    PubMed

    Liu, Chengchu; Lu, Jianzhang; Su, Yi-Cheng

    2009-01-01

    This study investigated the effects of flash freezing, followed by frozen storage, on reducing Vibrio parahaemolyticus in Pacific raw oysters. Raw Pacific oysters were inoculated with a five-strain cocktail of V. parahaemolyticus at a total level of approximately 3.5 x 10(5) most probable number (MPN) per gram. Inoculated oysters were subjected to an ultralow flash-freezing process (-95.5 degrees C for 12 min) and stored at -10, -20, and -30 degrees C for 6 months. Populations of V. parahaemolyticus in the oysters declined slightly by 0.22 log MPN/g after the freezing process. Subsequent storage of frozen oysters at - 10, -20, and -30 degrees C resulted in considerable reductions of V. parahaemolyticus in the oysters. Storing oysters at -10 degrees C was more effective in inactivating V. parahaemolyticus than was storage at -20 or -30 degrees C. Populations of V. parahaemolyticus in the oysters declined by 2.45, 1.71, and 1.45 log MPN/g after 1 month of storage at -10, -20, and -30 degrees C, respectively, and continued to decline during the storage. The levels of V. parahaemolyticus in oysters were reduced by 4.55, 4.13, and 2.53 log MPN/g after 6 months of storage at -10, -20, and -30 degrees C, respectively. Three process validations, each separated by 1 week and conducted according to the National Shellfish Sanitation Program's postharvest processing validation-verification interim guidance for Vibrio vulnificus and Vibrio parahaemolyticus, confirmed that a process of flash freezing, followed by storage at -21 +/- 2 degrees C for 5 months, was capable of achieving greater than 3.52-log (MPN/g) reductions of V. parahaemolyticus in half-shell Pacific oysters.

  1. Application of oysters as useful concentration indicators to evaluate the fate of xenoestrogenic alkylphenols along the western coastal areas of Taiwan

    NASA Astrophysics Data System (ADS)

    Ding, Wanghsien

    2016-04-01

    The oyster is an important aquacultural species in Taiwan. Since oysters naturally inhabit shelves near the coast, samples from particular "oyster cultural sites" can be applied to evaluate the pollution levels of segments of coastal water. Insufficient wastewater treatment has caused untreated wastewaters to flow into rivers, and hence, into oyster cultural areas in estuaries as well as shallow coastal waters. Therefore, the concentration of pollutants in the oysters can be used as concentration indicators to evaluate the fate of the pollutants on the western coastal areas of Taiwan. In this study, xenoestrogenic alkylphenols were determined in oyster samples by extractive steam distillation prior to their determination by gas chromatography - mass spectrometry. The results show that a group of 4-nonylphenol isomers (4-NPs) were ubiquitous in oysters with concentration levels ranging from 23 to 3370 ng/g (wet weight). The concentrations of 4-NPs varied with different levels of 4-NPs found across unrelated estuaries water samples, and higher level of 4-NPs in water samples caused higher concentration of 4-NPs found in oyster tissue samples. Moreover, at the same oyster sites mentioned previously, the levels of 4-NPs in oysters decreased significantly after the year 2008. This drop in 4-NPs level can be attributed to environmental regulations that banned 4-NPs as additives in household cleaning agents since January 2008 in Taiwan. Due to the mentioned reasons, oysters are concluded to be useful organic pollutant concentration indicators in marine environments.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Continuous fission-product monitor system at Oyster Creek. Final report

    SciTech Connect

    Collins, L.L.; Chulick, E.T.

    1980-10-01

    A continuous on-line fission product monitor has been installed at the Oyster Creek Nuclear Generating Station, Forked River, New Jersey. The on-line monitor is a minicomputer-controlled high-resolution gamma-ray spectrometer system. An intrinsic Ge detector scans a collimated sample line of coolant from one of the plant's recirculation loops. The minicomputer is a Nuclear Data 6620 system. Data were accumulated for the period from April 1979 through January 1980, the end of cycle 8 for the Oyster Creek plant. Accumulated spectra, an average of three a day, were stored on magnetic disk and subsequently analyzed for fisson products, Because of difficulties in measuring absolute detector efficiency, quantitative fission product concentrations in the coolant could not be determined. Data for iodine fission products are reported as a function of time. The data indicate the existence of fuel defects in the Oyster Creek core during cycle 8.

  4. A pilot study on remediation of sediments enriched by oyster farming wastes using granulated coal ash.

    PubMed

    Yamamoto, T; Kim, K H; Shirono, K

    2015-01-15

    In order to evaluate the ability of granulated coal ash (GCA), a byproduct of coal thermal electric power stations, to remove hydrogen sulfide from organically enriched sediments, a pilot study was carried out at oyster farming sites, where sediments were enriched with oyster feces and dead oysters. Concentration of hydrogen sulfide in the interstitial water of the sediment decreased to nearly zero in both experimental sites, whereas it remained over 0.2mg/l in the control site. Concentration of acid volatile sulfide (AVS) in the sediment also decreased significantly in both experimental sites, while remained over 0.4 mg/g in the control site. Increases were observed in both the number of benthic microalgae species and the individual number of benthic animals in the surface sediments. This may have been due to the decrease in hydrogen sulfide.

  5. Vibrio gastroenteritis in the US Gulf of Mexico region: the role of raw oysters.

    PubMed

    Altekruse, S F; Bishop, R D; Baldy, L M; Thompson, S G; Wilson, S A; Ray, B J; Griffin, P M

    2000-06-01

    We examined clinical and epidemiological features of 575 laboratory-confirmed cases of vibrio gastroenteritis in Alabama, Florida, Louisiana, and Texas from 1988 to 1997 (the US Gulf of Mexico Regional Vibrio Surveillance System). Illnesses occurred year round, with peaks in spring and autumn. Illnesses lasted a median of 7 days and included fever in half of patients and bloody stools in 25% of patients with relevant information. Seventy-two percent of patients reported no underlying illnesses. In the week before onset, 236 (53%) of 445 patients for whom data were available ate raw oysters, generally at a restaurant or bar. Educational efforts should address the risk of vibrio gastroenteritis for raw oyster consumers, including healthy individuals. Further studies should examine environmental conditions affecting vibrio counts on seafood and processing technologies to enhance the safety of raw oysters.

  6. Oyster-bioimmured ammonites from the Upper Albian of Annopol, Poland: stratigraphic and palaeobiogeographic implications

    NASA Astrophysics Data System (ADS)

    Machalski, Marcin; Kennedy, William J.

    2013-12-01

    Machalski, M. and Kennedy, W.J. 2013. Oyster-bioimmured ammonites from the Upper Albian of Annopol, Poland: stratigraphic and palaeobiogeographic implications. Acta Geologica Polonica, 63 (4), 545-554. Warszawa. Ammonites Mortoniceras (Subschloenbachia) sp. are preserved as attachment scars on the oyster shells from the topmost portion of the Albian succession at Annopol, Poland. These oyster-bioimmured ammonites show a closest affinity to the representatives of Mortoniceras (Subschloenbachia) characteristic of the upper Upper Albian Mortoniceras perinflatum Zone. No ammonites indicative of the uppermost Albian-lowermost Cenomanian Praeschloenbachia briacensis Zone are recorded. Thus, the hiatus at the Albian-Cenomanian boundary at Annopol embraces the latter zone. The presence (and dominance) of Mortoniceras in the upper Upper Albian ammonite assemblage of Annopol suggests that the representatives of this Tethyan genus could migrate into the epicratonic areas of Poland directly from the Tethyan Realm, via the Lwow (Lviv) region.

  7. Denman Island disease in Washington State, USA: distribution and prevalence in Pacific and Olympia oysters.

    PubMed

    Elston, Ralph; Friedman, Carolyn; Gustafson, Lori; Meyer, Gary; Rogers, Russell

    2015-05-21

    We sampled over 2400 wild, feral, and cultured Pacific oysters Crassostrea gigas and Olympia oysters Ostrea lurida in Washington State, USA, from 2002 to 2006 to estimate the prevalence of infection with Mikrocytos mackini, the causative agent of Denman Island disease. Both histology and qualitative PCR methods were used. Estimates of true prevalence of M. mackini infection in C. gigas, after accounting for imperfect test sensitivity, ranged from mean values of 0 to 10.0% by histology and 0 to 8.4% based on pooled PCR samples. M. mackini was not detected in any of the O. lurida samples. Results suggest a lower prevalence of the pathogen and severity of this oyster disease in Washington than that indicated in previous reports from British Columbia, Canada, potentially attributable to higher seawater temperatures in the Washington sample locations.

  8. Effects of temperature and chelating agents on cadmium uptake in the American oyster

    SciTech Connect

    Hung, Y.W.

    1982-05-01

    The effect of temperature on cadmium accumulations was evaluated in the tissue of the American oyster, Crassostrea virginica, under controlled laboratory conditions. Oysters have been reported to accumulate cadmium from seawater containing added cadmium chloride. However, the chemical form of cadmium in seawater has not been defined. This may profoundly influence the mechanism of uptake. Therefore, the report is also concerned with the effect of chelating agents on the uptake of cadmium. Chelating agents used were nitrilotriacetic acid, ethylene diaminetetraacetic acid and humic acid. At the end of a 40-day exposure to cadmium, 15 oysters were randomly selected from each tank of synthetic seawater, and each was dissected into 5 fractions, namely gills, mantle, adductor muscle, hepatopancreas and the remainder. The cadmium content of each fraction was analyzed by atomic absorption spectrophotometry with a flameless graphite furnace. (JMT)

  9. Tulane Virus as a Potential Surrogate To Mimic Norovirus Behavior in Oysters

    PubMed Central

    Drouaz, Najoua; Schaeffer, Julien; Farkas, Tibor; Le Pendu, Jacques

    2015-01-01

    Oyster contamination by noroviruses is an important health and economic problem. The present study aimed to compare the behaviors of Norwalk virus (the prototype genogroup I norovirus) and two culturable viruses: Tulane virus and mengovirus. After bioaccumulation, tissue distributions were quite similar for Norwalk virus and Tulane virus, with the majority of viral particles detected in digestive tissues, while mengovirus was detected in large amounts in the gills and mantle as well as in digestive tissues. The levels of persistence of all three viruses over 8 days were comparable, but clear differences were observed over longer periods, with Norwalk and Tulane viruses displaying rather similar half-lives, unlike mengovirus, which was cleared more rapidly. These results indicate that Tulane virus may be a good surrogate for studying norovirus behavior in oysters, and they confirm the prolonged persistence of Norwalk virus in oyster tissues. PMID:26025893

  10. Relationship between the lability of sediment-bound Cd and its bioaccumulation in edible oyster.

    PubMed

    Chakraborty, Parthasarathi; Ramteke, Darwin; Chakraborty, Sucharita; Chennuri, Kartheek; Bardhan, Pratirupa

    2015-11-15

    A linkage between Cd speciation in sediments and its bioaccumulation in edible oyster (Crassostrea sp.) from a tropical estuarine system was established. Bioaccumulation of Cd in edible oyster increased with the increasing lability and dissociation rate constants of Cd-sediment complexes in the bottom sediments. Total Cd concentration in sediment was not a good indicator of Cd-bioavailability. Increasing trace metal competition in sediments increased lability and bioavailability of Cd in the tropical estuarine sediment. Low thermodynamic stability and high bioavailability of Cd in the estuarine sediment were responsible for high bioaccumulation of Cd in edible oysters (3.2-12.2mgkg(-1)) even though the total concentration of Cd in the bottom sediment was low (0.17-0.49mgkg(-1)).

  11. Preparation and characterization of coacervate microcapsules for the delivery of antimicrobial oyster peptides.

    PubMed

    Zhang, Li; Liu, Yezhou; Wu, Zhongchen; Chen, Haixu

    2009-03-01

    Oyster peptides-loaded alginate/chitosan/starch microcapsules were prepared using external gelation method and internal emulsion gelation method. The solution of oyster peptides complexes was encapsulated into the microcapsules, which endowed the microcapsules with intestine passive targeting properties. The swelling behavior, encapsulation efficiency, and release behavior of oyster peptides from the microcapsules at different pH values were investigated. The microcapsules exhibited sustained release of the peptides in intestinal medium, and the release rate could be regulated by the pH value: in simulated gastric fluid, the release rate was greatly decreased, and in simulated body fluid and intestinal fluid, the microcapsules exhibited a sustained release in 24 h with different release rates. The microspheres were characterized by Fourier transform infrared. The results suggested that the alginate/chitosan/starch microcapsules could be a suitable copolymeric carrier system for intestinal protein or peptides delivery in the intestine.

  12. Hybrid production of oyster mushroom Pleurotus ostreatus (Jacq: Fries) Kummer.

    PubMed

    Gharehaghaji, A Nikzad; Goltapeh, E Mohammadi; Masiha, S; Gordan, H R

    2007-07-15

    Optimization of industrial mushroom production depends on improving the culture process and breeding new strains with higher yields and productivities. So many works have been done on process improvement, Although few systematic studies of genetic breeding of Pleurotus ostreatus strains have been reported. The major aim of hybridization is to combine desirable characteristics from different strains and create variability in the existing germ plasm. In this study, we used a breeding approach to hybrid production from cultivated Oyster mushrooms Pleurotus ostreatus. Five strains of Pleurotus ostreatus (Jacq: Fries) Kummer were used in this research. Basidiospores were suspended in sterile distilled water and counted with a haemocytometer. After germination, colony of each isolate transferred into the PDA medium. Growth rate and colony type of each isolate was determined and then 17 monokaryons were selected. Consequently screening monokaryons were crossed to each other. Some characteristics such as morphological interaction in the contact zone of mycelium, increasing in growth rate of hybrid, change of colony morphology and the presence of clamp connections between dikaryotic cells used to distinction of monokaryons from dikaryons. We recognized 27 hybrids by these characteristics.

  13. Characterization of pseudomonads isolated from decaying sporocarps of oyster mushroom.

    PubMed

    Sajben, Eniko; Manczinger, László; Nagy, Adrienn; Kredics, László; Vágvölgyi, Csaba

    2011-05-20

    Pleurotus ostreatus is one of the most extensively cultivated mushrooms in the world; however, the success of cultivation often depends on the proliferation of different bacterial pathogens. Pseudomonas tolaasii is thought as the major cause of brown blotch disease of Agaricus bisporus and yellowing of Pleurotus ostreatus. In this study we examined the pathogenicity and assessed the industrial damage causing effect of 41 Pseudomonas strains isolated from deformed, yellowing oyster mushroom (P. ostreatus) sporocarps. Identification of the isolates at species level by the partial sequence analysis of the hypervariable region of the rpoB gene revealed nine Pseudomonas sps. We analyzed the presence of the tolaasin gene-cluster, the production of fluorescent pigments, the oxidase- and nitrite reductase activities, the growth at restrictive temperatures and the carbon source utilizing abilities of each strain. Complex lipopeptide production (including tolaasin) was examined with thin layer chromatography and a novel in vitro necrosis-test was developed and evaluated for the investigation of the pathogenic effect of Pseudomonas strains. Our results underline the importance of extracellular enzyme production in the sporocarp decaying process. Strong correlations were found between the secretion of trypsin-like proteases and lipases and the necrotic effect of these bacteria. All the results clearly established that besides Ps. tolaasii, Ps. fluorescens biovar V strains were pathogenic to P. ostreatus and cause serious losses during mushroom production. Our results underline the importance of extracellular enzyme production in the sporocarp decaying process, especially the trypsin-like proteases and lipases.

  14. Oyster toadfish fly on STS-90 as part of Neurolab

    NASA Technical Reports Server (NTRS)

    1998-01-01

    An oyster toadfish (Opsanus tau), like those that are part of the Neurolab payload on Space Shuttle Mission STS-90, is shown in its holding tank in the Space Station Processing Facility. Each fish is between eight and 14 inches long. Toadfish live in an estuarine environment and are native to areas along the Northeast coast of the United States. Since they are bottom dwellers that live in cracks and crevices, a tube is provided in its tank to give it a place to retreat and hide. Investigations during the Neurolab mission will focus on the effects of microgravity on the nervous system. This fish is an excellent model for looking at vestibular function because the architecture of its inner and middle ear are similar to those of mammals with respect to the vestibular apparatus. The crew of STS-90, slated for launch April 16 at 2:19 p.m. EDT, includes Commander Richard Searfoss, Pilot Scott Altman, Mission Specialists Richard Linnehan, Dafydd (Dave) Williams, M.D., and Kathryn (Kay) Hire, and Payload Specialists Jay Buckey, M.D., and James Pawelczyk, Ph.D.

  15. Oyster toadfish fly on STS-90 as part of Neurolab

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Oyster toadfish (Opsanus tau), like those that are part of the Neurolab payload on Space Shuttle Mission STS-90, are shown in their holding tank in the Space Station Processing Facility. Each fish is between 8 and 14 inches long. Toadfish live in an estuarine environment and are native to areas along the Northeast coast of the United States. Since they are bottom dwellers that live in cracks and crevices, tubes are provided in their tank to give them a place to retreat and hide. Investigations during the Neurolab mission will focus on the effects of microgravity on the nervous system. The toadfish fish is an excellent model for looking at vestibular function because the architecture of its inner and middle ear are similar to those of mammals with respect to the vestibular apparatus. The crew of STS-90, slated for launch April 16 at 2:19 p.m. EDT, includes Commander Richard Searfoss, Pilot Scott Altman, Mission Specialists Richard Linnehan, Dafydd (Dave) Williams, M.D., and Kathryn (Kay) Hire, and Payload Specialists Jay Buckey, M.D., and James Pawelczyk, Ph.D.

  16. Evaluation of ANF fuel failures in oyster creek

    SciTech Connect

    Howe, T.M.; Van Swam, L.F.; Piascik, T.G.; Spence, P.A.

    1988-01-01

    During the refueling outrage following cycle-10 operations of Oyster Creek nuclear generating station, fuel sipping identified 47 failed Advance Nuclear Fuels (ANF) fuel assemblies. The failed fuel was an unpressurized 8 x 8 design manufactured by ANF prior to 1980. Subsequent inspection of 46 of these 47 assemblies with the ANF ULTRATEST ultrasonic testing system indicated 104 either failed of suspect fuel rods in 44 assemblies. Two of the assemblies were identified as being sound. Selected fuel rods were removed from three of the assemblies and inspected both visually and with an eddycurrent coil. An evaluation has been performed to determine the cause of the failures. The failures were primarily the result of pellet/cladding interaction (PCI). Detailed analyses of several of the failed fuel rods were performed with ANF's fuel rod modeling code RAMPX2. RAMPX2 includes several state-of-the-art models, including a model describing the formation of fission product deposits called coins on the inside surface of the cladding, a model that accounts for axial PCI, and a trapped fuel stack model. The analyses provided an explanation for the failures.

  17. Ocean breeze monitoring network at the Oyster Creek Nuclear Plant

    SciTech Connect

    Heck, W.

    1987-01-01

    The Oyster Creek Nuclear Generating Station (OCNGS) is located in New Jersey 10 km west of the Atlantic Ocean. Routine meteorological monitoring at the station has consisted of a single meteorological tower 120 m high and instrumented at the 10-m, 46-m, and 116-m levels. An analysis of 5 yr of data from this tower showed the OCNGS is affected by an ocean breeze approx. 1 day out of 4 during May through August. This suggested the need for meteorological monitoring in addition to the single met tower at OCNGS. As a result of the 1985 OCNGS meteorological monitoring study, GPU Nuclear established an ocean breeze monitoring network in the fall of 1986. It is a permanent part of OCNGS meteorological monitoring and consists of the same sites as used in the 1985 field study. Meteorological towers are located at the ocean site, the inland site, and at OCNGS. The ocean tower is 13 m (43 ft) high, the inland tower 10 m (33 ft), and the OCNGS tower 116 m (380 ft). Wind speed, wind direction, and temperature are measured on each tower; delta-temperature is also measured on the main tower. The instruments are calibrated in the spring, summer, and fall. The network is operated and maintained by GPU Nuclear Environmental Controls. The ocean breeze monitoring network and meteorological information system forms the basis for including the effects of the ocean breeze in OCNGS emergency off-site dose assessment.

  18. Antimicrobial susceptibility of Vibrio alginolyticus isolated from oyster in Korea.

    PubMed

    Kang, Chang-Ho; Shin, YuJin; Jang, SeokCheol; Jung, Yeojung; So, Jae-Seong

    2016-10-01

    Pathogenic Vibrio alginolyticus, a cause of severe infection in shellfish, as well as in humans, has been found at high frequency around all coastal areas of Korea. The aim of this study was to determine the occurrence of V. alginolyticus, to identify the strains isolated from oysters in West Sea, and to investigate their antimicrobial resistance profiles. Biochemical analyses of the 90 initially recovered presumptive V. alginolyticus colonies indicated that 16 isolates were V. alginolyticus. PCR analysis to detect the presence of the gyrB gene confirmed that 15 (93.8 %) of the 16 isolates were V. alginolyticus. These 15 isolates had the following profiles of resistance against 16 antibiotics: all isolates were resistant to ampicillin and vancomycin, and 26.7 % of the isolates exhibited resistance to cephalothin. A large number of isolates showed intermediate resistance to erythromycin (100 %) and rifampin (73.3 %). Five (33.3 %) of the V. alginolyticus isolates demonstrated multiple resistance to at least three antimicrobials.

  19. Oyster toadfish fly on STS-90 as part of Neurolab

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Bill Kroeger, an aquatic technician for the Bionetics Corporation, examines an oyster toadfish (Opsanus tau), like those that are part of the Neurolab payload on Space Shuttle Mission STS-90, in its holding tank in the Space Station Processing Facility. Each fish is between eight and 14 inches long. Toadfish live in an estuarine environment and are native to areas along the Northeast coast of the United States. Investigations during the Neurolab mission will focus on the effects of microgravity on the nervous system. This fish is an excellent model for looking at vestibular function because the architecture of its inner and middle ear are similar to those of mammals with respect to the vestibular apparatus. The crew of STS-90, slated for launch April 16 at 2:19 p.m. EDT, includes Commander Richard Searfoss, Pilot Scott Altman, Mission Specialists Richard Linnehan, Dafydd (Dave) Williams, M.D., and Kathryn (Kay) Hire, and Payload Specialists Jay Buckey, M.D., and James Pawelczyk, Ph.D.

  20. Polycyclic aromatic hydrocarbons in rock oysters: a baseline study.

    PubMed

    Kagi, R; Alexander, R; Cumbers, M

    1985-01-01

    Coral-rock oysters were collected in September 1982 from six locations in the area of Mermaid Sound in North-Western Australia. Analysis was carried out by digestion of the samples, followed by solvent extraction and analysis of the extracts using HPLC-UVF and GC-MS. The levels of two- and three-ring aromatics ranged from very low for the site outside Mermaid Sound and for one site within the Sound, to low for the four other sites within the Sound. The PAH values at the latter four sites are attributed to occasional petroleum release episodes related to small boat activities and large-scale salt and iron ore shipping and general cargo activities of the Port of Dampier. The levels of PAHs with four or more rings were found to be low or very low at all sites; in fact, in most cases values measured for specific PAHs were below the limits of detection of even the very sensitive methods used in this study. Samples from sites within Mermaid Sound closest to the town and port of Dampier showed noticeably higher levels than those from outside; the present study does not allow the source of the PAHs to be determined. It is interesting to note, however, that the parent PAHs appear to form a greater proportion of the total PAH assemblage in these cases, indicating contributions from material which has been subjected to high temperature processing prior to release into the Sound.

  1. Cristispira from oyster styles: complex morphology of large symbiotic spirochetes

    NASA Technical Reports Server (NTRS)

    Margulis, L.; Nault, L.; Sieburth, J. M.

    1991-01-01

    Crystalline styles (digestive organs) of bivalve mollusks provide the habitat for highly motile bacteria. Styles from freshly-collected oysters, Crassostrea virginica, were studied by electron microscopy; Cristispira spirochetes were abundant in these organs. Detailed study reveals these spirochetes to be among the most complex prokaryotic cells known. More than 600 periplasmic flagella and an adhering outer lipoprotein membrane (e.g., a 270 degrees sillon) form the ultrastructural basis for the "crista," first described by light microscopy. Unique rosette structures corresponding to the "chambers" or "ovoid inclusions" of light microscopy were detected at the periphery of all protoplasmic cylinders. Polar organelles and linearly aligned flagellar insertions are conspicuous. In size and complexity, Cristispira more resembles Pillotina, Diplocalyx, Clevelandina and Hollandina (large spirochetes symbiotic in termites) than it does Treponema. Cristispira pectinis (Gross, 1910), the type species; Spirillum ostrea (Noguchi, 1921); and another, less frequent bacterial symbiont are the predominant inhabitants of the dense style matrix. The ultrastructure of the spirillum and an electron micrograph of the third bacterium are shown.

  2. Biochemical, serological, and virulence characterization of clinical and oyster Vibrio parahaemolyticus isolates.

    PubMed

    Jones, Jessica L; Lüdeke, Catharina H M; Bowers, John C; Garrett, Nancy; Fischer, Markus; Parsons, Michele B; Bopp, Cheryl A; DePaola, Angelo

    2012-07-01

    In this study, 77 clinical and 67 oyster Vibrio parahaemolyticus isolates from North America were examined for biochemical profiles, serotype, and the presence of potential virulence factors (tdh, trh, and type III secretion system [T3SS] genes). All isolates were positive for oxidase, indole, and glucose fermentation, consistent with previous reports. The isolates represented 35 different serotypes, 9 of which were shared by clinical and oyster isolates. Serotypes associated with pandemic strains (O1:KUT, O1:K25, O3:K6, and O4:K68) were observed for clinical isolates, and 7 (9%) oyster isolates belonged to serotype O1:KUT. Of the clinical isolates, 27% were negative for tdh and trh, while 45% contained both genes. Oyster isolates were preferentially selected for the presence of tdh and/or trh; 34% contained both genes, 42% had trh but not tdh, and 3% had tdh but not trh. All but 1 isolate (143/144) had at least three of the four T3SS1 genes examined. The isolates lacking both tdh and trh contained no T3SS2α or T3SS2β genes. All clinical isolates positive for tdh and negative for trh possessed all T3SS2α genes, and all isolates negative for tdh and positive for trh possessed all T3SS2β genes. The two oyster isolates containing tdh but not trh possessed all but the vopB2 gene of T3SS2α, as reported previously. In contrast to the findings of previous studies, all strains examined that were positive for both tdh and trh also carried T3SS2β genes. This report identifies the serotype as the most distinguishing feature between clinical and oyster isolates. Our findings raise concerns about the reliability of the tdh, trh, and T3SS genes as virulence markers and highlight the need for more-detailed pathogenicity investigations of V. parahaemolyticus.

  3. Effects of intraspecific diversity on survivorship, growth, and recruitment of the eastern oyster across sites.

    PubMed

    Hanley, Torrance C; Hughes, A Randall; Williams, Bethany; Garland, Hanna; Kimbro, David L

    2016-06-01

    Intraspecific diversity, particularly of foundation species, can significantly affect population, community, and ecosystem processes. Examining how genetic diversity relates to demographic traits provides a key mechanistic link from genotypic and phenotypic variation of taxa with complex life histories to their population dynamics. We conducted a field experiment to assess how two metrics of intraspecific diversity (cohort diversity, the number of independent juvenile cohorts created from different adult source populations, and genetic relatedness, genetic similarity among individuals within and across cohorts) affect the survivorship, growth, and recruitment of the foundation species Crassostrea virginica. To assess the effects of both cohort diversity and genetic relatedness on oyster demographic traits under different environmental conditions, we manipulated juvenile oyster diversity and predator exposure (presence/absence of a cage) at two sites differing in resource availability and predation intensity. Differences in predation pressure between sites overwhelmingly determined post-settlement survivorship of oysters. However, in the absence of predation (i.e., cage treatment), one or both metrics of intraspecific diversity, in addition to site, influenced long-term survivorship, growth, and recruitment. While both cohort diversity and genetic relatedness were negatively associated with long-term survivorship, genetic relatedness alone showed a positive association with growth and cohort diversity alone showed a positive association with recruitment. Thus, our results demonstrate that in the absence of predation, intraspecific diversity can affect multiple demographic traits of a foundation species, but the relative importance of these effects depends on the environmental context. Moreover, the magnitude and direction of these effects vary depending on the diversity metric, cohort diversity or genetic relatedness, suggesting that although they are inversely

  4. Cellular responses and disease expression in oysters (Crassostrea virginica) exposed to suspended field contaminated sediments.

    PubMed

    Chu, Fu-Lin E; Volety, Aswani K; Hale, Robert C; Huang, Yongqin

    2002-02-01

    Exposure of oysters to water soluble fractions derived from field-contaminated sediments (FCS) containing predominantly lower molecular weight organic aromatic compounds, has been previously demonstrated to enhance pre-existing infections caused by the protozoan parasite, Perkinsus marinus (Dermo), and the prevalence of experimentally induced infections. To further explore the role of pollution on the onset and progression of disease, effects of suspended FCS from an estuarine creek in Virginia, USA, dominated by higher molecular weight polycyclic aromatic hydrocarbons (PAHs) on cellular responses and Dermo disease expression in oysters (Crassostrea virginica) were examined. Sediments were collected from a PAH polluted estuarine creek in Virginia, USA. To test effects on cellular response, oysters from Maine were exposed daily to 0, 1.0, 1.5, or 2.0 g suspended FCS (corresponding to 0, 70.2, 105, or 140 microg PAHs, respectively) for 5, 10, 20, and 40 days. Hemocyte activities and plasma lipid, protein and lactate dehydrogenase (LDH) levels were then measured. Exposure stimulated neutral red uptake, MTT reduction, and 3H-leucine incorporation in oyster hemocytes at various exposure times, but did not affect the plasma protein, lipid and LDH levels. To test effects on Dermo expression, oysters from a Dermo enzootic area, with an initial estimated infection prevalence of 39%, were exposed daily to 0, 1.0, 1.5, or 2.0 g suspended FCS (corresponding to 0, 75.0, 113, or 150 microg PAHs, respectively) for 30 days. Exposure enhanced disease expression in oysters. However, no significant change was noted in any measured cellular or humoral parameters.

  5. Relative importance of hydrocarbon pollutants, salinity and tidal height in colonization of oyster reefs.

    PubMed

    Hulathduwa, Yasoma D; Brown, Kenneth M

    2006-10-01

    The relative effects of hydrocarbon pollutants, salinity and tidal height on the invertebrates and fish that inhabit oyster reefs were studied along the Louisiana Gulf of Mexico coastline. Dried oyster shell (cultch) was first exposed to crude oil in the laboratory. In a series of experiments, plastic trays filled with control and oil-exposed cultch were then deployed at two locations differing in salinity, in two seasons and at two tidal levels. In experiments on hydrocarbon, salinity, and seasonal effects, trays were colonized for one month. To examine the effects of colonization time, half of the trays were retrieved after two and the rest after five weeks. Salinity dramatically affected oyster reef assemblages, with species richness and total abundance halved at the estuarine site. Hydrocarbon effects were less prominent, whether cultch was dosed with light or heavy crude oil. The sub-tidal site had higher colonization rates, but colonization interval did not affect colonization, and seasonal differences occurred only at the higher-diversity, sub-tidal site. To determine effects of cleaners, Corexit 9580 was applied alone and with oil on cultch, and trays were colonized for one month. At high concentrations, the cleaner ameliorated hydrocarbon effects. In general, hydrocarbon effects were less prominent than salinity and aerial exposure in explaining colonization of oyster reef assemblages. Gas chromatography/mass spectrometry analysis of oyster shells after one month immersion revealed considerable losses of oil, especially with higher flow at the inter-tidal site. Sediment on shell also diluted oil. We argue that oyster reef assemblages should recover from small-scale spills, unless they occur during periods of reproduction and dispersal.

  6. Oyster reefs as natural breakwaters mitigate shoreline loss and facilitate fisheries.

    PubMed

    Scyphers, Steven B; Powers, Sean P; Heck, Kenneth L; Byron, Dorothy

    2011-01-01

    Shorelines at the interface of marine, estuarine and terrestrial biomes are among the most degraded and threatened habitats in the coastal zone because of their sensitivity to sea level rise, storms and increased human utilization. Previous efforts to protect shorelines have largely involved constructing bulkheads and seawalls which can detrimentally affect nearshore habitats. Recently, efforts have shifted towards "living shoreline" approaches that include biogenic breakwater reefs. Our study experimentally tested the efficacy of breakwater reefs constructed of oyster shell for protecting eroding coastal shorelines and their effect on nearshore fish and shellfish communities. Along two different stretches of eroding shoreline, we created replicated pairs of subtidal breakwater reefs and established unaltered reference areas as controls. At both sites we measured shoreline and bathymetric change and quantified oyster recruitment, fish and mobile macro-invertebrate abundances. Breakwater reef treatments mitigated shoreline retreat by more than 40% at one site, but overall vegetation retreat and erosion rates were high across all treatments and at both sites. Oyster settlement and subsequent survival were observed at both sites, with mean adult densities reaching more than eighty oysters m(-2) at one site. We found the corridor between intertidal marsh and oyster reef breakwaters supported higher abundances and different communities of fishes than control plots without oyster reef habitat. Among the fishes and mobile invertebrates that appeared to be strongly enhanced were several economically-important species. Blue crabs (Callinectes sapidus) were the most clearly enhanced (+297%) by the presence of breakwater reefs, while red drum (Sciaenops ocellatus) (+108%), spotted seatrout (Cynoscion nebulosus) (+88%) and flounder (Paralichthys sp.) (+79%) also benefited. Although the vertical relief of the breakwater reefs was reduced over the course of our study and this

  7. Longitudinal study of winter mortality disease in Sydney rock oysters Saccostrea glomerata.

    PubMed

    Spiers, Zoe B; Gabor, Melinda; Fell, Shayne A; Carnegie, Ryan B; Dove, Michael; O'Connor, Wayne; Frances, Jane; Go, Jeffrey; Marsh, Ian B; Jenkins, Cheryl

    2014-07-24

    Winter mortality (WM) is a poorly studied disease affecting Sydney rock oysters Saccostrea glomerata in estuaries in New South Wales, Australia, where it can cause significant losses. WM is more severe in oysters cultured deeper in the water column and appears linked to higher salinities. Current dogma is that WM is caused by the microcell parasite Bonamia roughleyi, but evidence linking clinical signs and histopathology to molecular data identifying bonamiasis is lacking. We conducted a longitudinal study between February and November 2010 in 2 estuaries where WM has occurred (Georges and Shoalhaven Rivers). Results from molecular testing of experimental oysters for Bonamia spp. were compared to clinical disease signs and histopathology. Available environmental data from the study sites were also collated and compared. Oyster condition declined over the study period, coinciding with decreasing water temperatures, and was inversely correlated with the presence of histological lesions. While mortalities occurred in both estuaries, only oysters from the Georges River study site showed gross clinical signs and histological changes characteristic of WM (lesions were prevalent and intralesional microcell-like structures were sometimes noted). PCR testing for Bonamia spp. revealed the presence of an organism belonging to the B. exitiosa-B. roughleyi clade in some samples; however, the very low prevalence of this organism relative to histological changes and the lack of reactivity of affected oysters in subsequent in situ hybridisation experiments led us to conclude that this Bonamia sp. is not responsible for WM. Another aetiological agent and a confluence of environmental factors are a more likely explanation for the disease.

  8. The recycling of oyster shells: an environmental analysis using Life Cycle Assessment.

    PubMed

    de Alvarenga, Rodrigo Augusto Freitas; Galindro, Bruno Menezes; Helpa, Camile de Fátima; Soares, Sebastião Roberto

    2012-09-15

    Oysters represent a substantial fraction of the world's overall intensive aquaculture production. In Brazil, oyster aquaculture is still in the deployment phase but has the potential for growth and, likewise other aquaculture products, generate environmental impacts over their life cycle. Special attention should be devoted to the disposal or processing of the oyster shells, whose high calcium carbonate content (80-95%) gives them the potential for use as raw material for several other products. The objective of this study was to conduct a cradle-to-grave Life Cycle Assessment (LCA) of 1 kg of oysters produced in southern Brazil, incorporating the recycling of the oyster shells on the LCA. Two scenarios were considered. The first scenario (termed scenario A) assumed that the oyster shells were deposited in a landfill, whereas the second scenario (scenario B) assumed that the shells were processed to make them available as raw material as a source of CaCO(3). We used Eco-indicator 99 H/A to perform the impact assessment. Scenario A had an overall impact of 93.71 mPt, whereas scenario B had an overall impact of 58.97 mPt. The latter scenario had lower environmental impacts, however they were depended strongly on the distance between the source of the shells (restaurant) and the shell-processing facility. This distance must not be greater than 323 km to yield overall environmental benefits. Moreover, it is hypothesized that the environmental benefits would be even higher than predicted because there is no evidence that all post-consumer shell residues would receive proper waste management, as assumed for scenario A (landfill).

  9. Recovery, Bioaccumulation, and Inactivation of Human Waterborne Pathogens by the Chesapeake Bay Nonnative Oyster, Crassostrea ariakensis

    PubMed Central

    Graczyk, Thaddeus K.; Girouard, Autumn S.; Tamang, Leena; Nappier, Sharon P.; Schwab, Kellogg J.

    2006-01-01

    The introduction of nonnative oysters (i.e., Crassostrea ariakensis) into the Chesapeake Bay has been proposed as necessary for the restoration of the oyster industry; however, nothing is known about the public health risks related to contamination of these oysters with human pathogens. Commercial market-size C. ariakensis triploids were maintained in large marine tanks with water of low (8-ppt), medium (12-ppt), and high (20-ppt) salinities spiked with 1.0 × 105 transmissive stages of the following human pathogens: Cryptosporidium parvum oocysts, Giardia lamblia cysts, and microsporidian spores (i.e., Encephalitozoon intestinalis, Encephalitozoon hellem, and Enterocytozoon bieneusi). Viable oocysts and spores were still detected in oysters on day 33 post-water inoculation (pwi), and cysts were detected on day 14 pwi. The recovery, bioaccumulation, depuration, and inactivation rates of human waterborne pathogens by C. ariakensis triploids were driven by salinity and were optimal in medium- and high-salinity water. The concentration of human pathogens from ambient water by C. ariakensis and the retention of these pathogens without (or with minimal) inactivation and a very low depuration rate provide evidence that these oysters may present a public health threat upon entering the human food chain, if harvested from polluted water. This conclusion is reinforced by the concentration of waterborne pathogens used in the present study, which was representative of levels of infectious agents in surface waters, including the Chesapeake Bay. Aquacultures of nonnative oysters in the Chesapeake Bay will provide excellent ecological services in regard to efficient cleaning of human-infectious agents from the estuarine waters. PMID:16672482

  10. Transcriptome Analysis of the Sydney Rock Oyster, Saccostrea glomerata: Insights into Molluscan Immunity

    PubMed Central

    Ertl, Nicole G.; O’Connor, Wayne A.; Papanicolaou, Alexie; Wiegand, Aaron N.

    2016-01-01

    Background Oysters have important ecological functions in their natural environment, acting as global carbon sinks and improving water quality by removing excess nutrients from the water column. During their life-time oysters are exposed to a variety of pathogens that can cause severe mortality in a range of oyster species. Environmental stressors encountered in their habitat can increase the susceptibility of oysters to these pathogens and in general have been shown to impact on oyster immunity, making immune parameters expressed in these marine animals an important research topic. Results Paired-end Illumina high throughput sequencing of six S. glomerata tissues exposed to different environmental stressors resulted in a total of 484,121,702 paired-end reads. When reads and assembled transcripts were compared to the C. gigas genome, an overall low level of similarity at the nucleotide level, but a relatively high similarity at the protein level was observed. Examination of the tissue expression pattern showed that some transcripts coding for cathepsins, heat shock proteins and antioxidant proteins were exclusively expressed in the haemolymph of S. glomerata, suggesting a role in innate immunity. Furthermore, analysis of the S. glomerata ORFs showed a wide range of genes potentially involved in innate immunity, from pattern recognition receptors, components of the Toll-like signalling and apoptosis pathways to a complex antioxidant defence mechanism. Conclusions This is the first large scale RNA-Seq study carried out in S. glomerata, showing the complex network of innate immune components that exist in this species. The results confirmed that many of the innate immune system components observed in mammals are also conserved in oysters; however, some, such as the TLR adaptors MAL, TRIF and TRAM are either missing or have been modified significantly. The components identified in this study could help explain the oysters’ natural resilience against pathogenic

  11. Oyster Reefs as Natural Breakwaters Mitigate Shoreline Loss and Facilitate Fisheries

    PubMed Central

    Scyphers, Steven B.; Powers, Sean P.; Heck, Kenneth L.; Byron, Dorothy

    2011-01-01

    Shorelines at the interface of marine, estuarine and terrestrial biomes are among the most degraded and threatened habitats in the coastal zone because of their sensitivity to sea level rise, storms and increased human utilization. Previous efforts to protect shorelines have largely involved constructing bulkheads and seawalls which can detrimentally affect nearshore habitats. Recently, efforts have shifted towards “living shoreline” approaches that include biogenic breakwater reefs. Our study experimentally tested the efficacy of breakwater reefs constructed of oyster shell for protecting eroding coastal shorelines and their effect on nearshore fish and shellfish communities. Along two different stretches of eroding shoreline, we created replicated pairs of subtidal breakwater reefs and established unaltered reference areas as controls. At both sites we measured shoreline and bathymetric change and quantified oyster recruitment, fish and mobile macro-invertebrate abundances. Breakwater reef treatments mitigated shoreline retreat by more than 40% at one site, but overall vegetation retreat and erosion rates were high across all treatments and at both sites. Oyster settlement and subsequent survival were observed at both sites, with mean adult densities reaching more than eighty oysters m−2 at one site. We found the corridor between intertidal marsh and oyster reef breakwaters supported higher abundances and different communities of fishes than control plots without oyster reef habitat. Among the fishes and mobile invertebrates that appeared to be strongly enhanced were several economically-important species. Blue crabs (Callinectes sapidus) were the most clearly enhanced (+297%) by the presence of breakwater reefs, while red drum (Sciaenops ocellatus) (+108%), spotted seatrout (Cynoscion nebulosus) (+88%) and flounder (Paralichthys sp.) (+79%) also benefited. Although the vertical relief of the breakwater reefs was reduced over the course of our study and

  12. Estaurine Freshwater Entrainment By Oyster Reefs: Quantifying A Keystone Ecosystem Service

    NASA Astrophysics Data System (ADS)

    Kaplan, D. A.; Olabarrieta, M.; Frederick, P.; Valle-Levinson, A.; Seavey, J.

    2014-12-01

    Oyster reefs have been shown to provide myriad critical ecosystem services, however their role in directing flow and currents during non-storm conditions has been largely neglected. In many regions, oyster reefs form as linear structures perpendicular to the coast and across the path of streams and rivers, potentially entraining large volumes of freshwater flow and altering nearshore mixing. We hypothesize that these reefs have the potential to influence salinity over large areas, providing a "keystone" ecosystem service by supporting multiple estuarine functions. Here we present results from a field and modeling study to quantify the effects of reef extent and elevation on estuarine salinities under varying river discharge. We found salinity differences ranging from 2 to 16 g/kg between inshore and offshore sides of degraded oyster reefs in the Suwannee Sound (FL, USA), supporting the role of reefs as local-scale freshwater dams. Moreover, differences between inshore and offshore salinities were correlated with flow, with the most marked differences during periods of low flow. Hydrodynamic modeling using the 3-D Regional Ocean Modeling System (ROMS) suggests that the currently degraded reef system entrained greater volumes of freshwater in the past, buffering the landward advance of high salinities, particularly during low flow events related to droughts. Using ROMS, we also modeled a variety of hypothetical oyster bar morphology scenarios (historical, current, and "restored") to understand how changes in reef structure (elevation, extent, and completeness) impact estuarine mixing and near-shore salinities. Taken together, these results serve to: 1) elucidate a poorly documented ecosystem service of oyster reefs; 2) provide an estimate of the magnitude and sptial extent of the freshwater entrainment effect; and 3) offer quantitative information to managers and restoration specialists interested in restoring oyster habitat.

  13. Faunal community use of enhanced and natural oyster reefs in Delaware Bay: A field study and classroom inquiry

    NASA Astrophysics Data System (ADS)

    Paterno, Jenny L.

    In addition to its value as a fisheries resource, the eastern oyster Crassostrea virginica, is a reef building, cornerstone species that provides ecosystem services to the environment. Oysters provide habitat for associated resident and transient species. With widespread declines in oyster populations, restoration efforts have focused on improving oyster stocks and enhancing the ecosystem services they provide. Community-based oyster restoration programs engage the public and local community in planning, construction and/or monitoring of restoration projects. Since 2007, a K-12 student centered community-based restoration venture, Project PORTS, Promoting Oyster Restoration Through Schools, has been working to educate students, promote stewardship values, and enhance oyster habitat in the Delaware Bay. The overarching goals of the present study were to (1) assess fish and macroinvertebrate utilization on the Project PORTS community-created, subtidal, low-relief oyster restoration area in the Delaware Bay, and (2) convert the data collected into a STEM (Science, Technology, Engineering and Mathematics) activity that can be implemented in the classroom. I examined six subtidal natural oyster reefs of varying oyster densities and one community-based restoration reef as habitat for fishes and invertebrates. Sampling methods on these low-relief reefs consisted of otter trawl tows and benthic habitat tray collections. Results revealed that the enhancement area supported a diverse faunal community consistent with nearby, natural oyster habitats. Data collected during the field study were then transformed into an educational lesson plan, "One Fish, Two Fish-Assessing Habitat Value of Restored Oyster Reefs", that fulfilled national and state (NJ) curriculum standards. The lesson was piloted in a middle school classroom and student learning was evaluated through summative assessments pre and post-participation in the activity. Results of the assessments indicated that

  14. Molecular epidemiology of oyster-related human noroviruses and their global genetic diversity and temporal-geographical distribution from 1983 to 2014.

    PubMed

    Yu, Yongxin; Cai, Hui; Hu, Linghao; Lei, Rongwei; Pan, Yingjie; Yan, Shuling; Wang, Yongjie

    2015-11-01

    Noroviruses (NoVs) are a leading cause of epidemic and sporadic cases of acute gastroenteritis worldwide. Oysters are well recognized as the main vectors of environmentally transmitted NoVs, and disease outbreaks linked to oyster consumption have been commonly observed. Here, to quantify the genetic diversity, temporal distribution, and circulation of oyster-related NoVs on a global scale, 1,077 oyster-related NoV sequences deposited from 1983 to 2014 were downloaded from both NCBI GenBank and the NoroNet outbreak database and were then screened for quality control. A total of 665 sequences with reliable information were obtained and were subsequently subjected to genotyping and phylogenetic analyses. The results indicated that the majority of oyster-related NoV sequences were obtained from coastal countries and regions and that the numbers of sequences in these regions were unevenly distributed. Moreover, >80% of human NoV genotypes were detected in oyster samples or oyster-related outbreaks. A higher proportion of genogroup I (GI) (34%) was observed for oyster-related sequences than for non-oyster-related outbreaks, where GII strains dominated with an overwhelming majority of >90%, indicating that the prevalences of GI and GII are different in humans and oysters. In addition, a related convergence of the circulation trend was found between oyster-related NoV sequences and human pandemic outbreaks. This suggests that oysters not only act as a vector of NoV through environmental transmission but also serve as an important reservoir of human NoVs. These results highlight the importance of oysters in the persistence and transmission of human NoVs in the environment and have important implications for the surveillance of human NoVs in oyster samples.

  15. The use of a coal combustion by-product as substrate for oyster reef development

    SciTech Connect

    Andrews, R.S.; Alden, R.W. III; Luckenbach, M.

    1997-07-01

    In 1994, a multi-year study was initiated to determine the feasibility as well as the environmental acceptability of using pellets produced from fly ash from Virginia Power`s Chesapeake Energy Center (CEC). The intent of the study was to demonstrate a beneficial use for the fly ash that would compensate for natural reef losses by providing an alternate substrate for oyster attachment in the Chesapeake Bay. The results of the study indicate that pellets made from a mixture of approximately 88% CEC fly ash and 12% Type II Portland Cement are environmentally safe and facilitate the settlement, attachment and growth of oysters.

  16. Acute toxicity of oil and bilge cleaners to larval American oysters (Crassostrea virginica)

    SciTech Connect

    Sigler, M.; Leibovitz, L.

    1982-08-01

    The study examines the toxicities to oyster larvae of three bilge cleaners and No. 2 fuel oil, as well as a detergent which is used to clean larval culture containers. The three bilge cleaners and the one detergent were tested alone and in combination with No. 2 fuel oil. No. 2 fuel oil was also tested alone. The toxicity of these compounds to oyster larvae was determined in the laboratory under simulated hatchery conditions. Water levels of petroleum hydrocarbons were found to cause significant larval mortality. (JMT)

  17. Heavy-metal contamination of the Pacific oysters (Crassostrea gigas) cultured in Deep Bay, Hong Kong

    SciTech Connect

    Wong, M.H.; Choy, C.K.; Lau, W.M.; Cheung, Y.H.

    1981-08-01

    Samples of Pacific oysters, Crassostrea gigas, cultured in Deep Bay, Hong Kong, were collected for analysis of various heavy-metal contents: iron, copper, lead, cadmium, manganese, chromium, and zinc. In general, the gill had the highest metal contents, followed by the mantle, the viscera, with the smallest amount being observed in the adductor muscle. All metal contents obtained in the present study were within the range reported for the same species in areas where heavy-metal pollution is already recognized as a problem. A long-term monitoring program of measuring the contents of various metals in seawater, sediment, and oysters is therefore essential.

  18. Transcriptional changes in oysters Crassostrea brasiliana exposed to phenanthrene at different salinities.

    PubMed

    Zacchi, Flávia Lucena; de Lima, Daína; Flores-Nunes, Fabrício; Mattos, Jacó Joaquim; Lüchmann, Karim Hahn; de Miranda Gomes, Carlos Henrique Araújo; Bícego, Márcia Caruso; Taniguchi, Satie; Sasaki, Silvio Tarou; Dias Bainy, Afonso Celso

    2017-02-01

    Euryhaline animals from estuaries, such as the oyster Crassostrea brasiliana, show physiological mechanisms of adaptation to tolerate salinity changes. These ecosystems receive constant input of xenobiotics from urban areas, including polycyclic aromatic hydrocarbons (PAHs), such as phenanthrene (PHE). In order to understand the influence of salinity on the molecular responses of C. brasiliana exposed to PHE, oysters were acclimatized to different salinities (35, 25 and 10) for 15days and then exposed to 100μgL(-1) PHE for 24h and 96h. Control groups were kept at the same salinities without PHE. Oysters were sampled for chemical analysis and the gills were excised for mRNA quantification by qPCR. Transcript levels of different genes were measured, including some involved in oxidative stress pathways, phases I and II of the xenobiotic biotransformation systems, amino acid metabolism, fatty acid metabolism and aryl hydrocarbon receptor nuclear translocator putative gene. Higher transcript levels of Sulfotransferase-like gene (SULT-like) were observed in oysters exposed to PHE at salinity 10 compared to control (24h and 96h); cytochrome P450 isoforms (CYP2AU1, CYP2-like1) were more elevated in oysters exposed for 24h and CYP2-like2 after 96h of oysters exposed to PHE at salinity 10 compared to control. These results are probably associated to an enhanced Phase I biotransformation activity required for PHE detoxification under hyposmotic stress. Higher transcript levels of CAT-like, SOD-like, GSTm-like (96h) and GSTΩ-like (24h) in oysters kept at salinity 10 compared to organisms at salinities 25 and/or 35 are possibly related to enhaced ROS production. The transcription of these genes were not affected by PHE exposure. Amino acid metabolism-related genes (GAD-like (24h), GLYT-like, ARG-like (96h) and TAUT-like at 24h and 96h) also showed different transcription levels among organisms exposed to different salinities, suggesting their important role for oyster

  19. Insight into invertebrate defensin mechanism of action: oyster defensins inhibit peptidoglycan biosynthesis by binding to lipid II.

    PubMed

    Schmitt, Paulina; Wilmes, Miriam; Pugnière, Martine; Aumelas, André; Bachère, Evelyne; Sahl, Hans-Georg; Schneider, Tanja; Destoumieux-Garzón, Delphine

    2010-09-17

    Three oyster defensin variants (Cg-Defh1, Cg-Defh2, and Cg-Defm) were produced as recombinant peptides and characterized in terms of activities and mechanism of action. In agreement with their spectrum of activity almost specifically directed against Gram-positive bacteria, oyster defensins were shown here to be specific inhibitors of a bacterial biosynthesis pathway rather than mere membrane-active agents. Indeed, at lethal concentrations, the three defensins did not compromise Staphylococcus aureus membrane integrity but inhibited the cell wall biosynthesis as indicated by the accumulation of the UDP-N-acetylmuramyl-pentapeptide cell wall precursor. In addition, a combination of antagonization assays, thin layer chromatography, and surface plasmon resonance measurements showed that oyster defensins bind almost irreversibly to the lipid II peptidoglycan precursor, thereby inhibiting the cell wall biosynthesis. To our knowledge, this is the first detailed analysis of the mechanism of action of antibacterial defensins produced by invertebrates. Interestingly, the three defensins, which were chosen as representative of the oyster defensin molecular diversity, bound differentially to lipid II. This correlated with their differential antibacterial activities. From our experimental data and the analysis of oyster defensin sequence diversity, we propose that oyster defensin activity results from selective forces that have conserved residues involved in lipid II binding and diversified residues at the surface of oyster defensins that could improve electrostatic interactions with the bacterial membranes.

  20. Gauging state-level and user group views of oyster reef restoration activities in the northern Gulf of Mexico

    USGS Publications Warehouse

    LaPeyre, Megan K.; Nix, Ashby; Laborde, Luke; Piazza, Bryan P.

    2012-01-01

    Successful oyster reef restoration, like many conservation challenges, requires not only biological understanding of the resource, but also stakeholder cooperation and political support. To measure perceptions of oyster reef restoration activities and priorities for future restoration along the northern Gulf of Mexico coast, a survey of 1500 individuals representing 4 user groups (oyster harvesters, shrimpers, environmental organization members, professionals), across 5 states (Texas, Louisiana, Mississippi, Alabama, Florida) was conducted in 2011. All respondents highly supported reef restoration efforts, but there was a dichotomy in preferred restoration goals with commercial fishermen more likely to support oyster reef restoration for stock enhancement, while professionals and environmental organization members were more likely to support oyster reef restoration to enhance ecosystem services. All user groups identified enforcement, funding, and appropriate site selection as basic requirements for successful reef restoration. For management of restored oyster reefs, oyster harvesters and shrimpers were less likely to support options that restricted the use of reefs, including gear restrictions and permanent closures, but did support rotating annual reef closures, while other stakeholders were willing to consider all options, including annual reef closures and sanctuary reefs. Overall, there were clear differences in management and communication preferences across user groups, but few differences across states. Understanding these key differences in stakeholder support for, and willingness to accept specific management actions is critical in moving management and restoration forward while minimizing conflict.

  1. Molecular Cloning and Characterization of Full-Length cDNA of Calmodulin Gene from Pacific Oyster Crassostrea gigas

    PubMed Central

    Li, Xing-Xia; Yu, Wen-Chao; Cai, Zhong-Qiang; He, Cheng; Wei, Na

    2016-01-01

    The shell of the pearl oyster (Pinctada fucata) mainly comprises aragonite whereas that of the Pacific oyster (Crassostrea gigas) is mainly calcite, thereby suggesting the different mechanisms of shell formation between above two mollusks. Calmodulin (CaM) is an important gene for regulating the uptake, transport, and secretion of calcium during the process of shell formation in pearl oyster. It is interesting to characterize the CaM in oysters, which could facilitate the understanding of the different shell formation mechanisms among mollusks. We cloned the full-length cDNA of Pacific oyster CaM (cgCaM) and found that the cgCaM ORF encoded a peptide of 113 amino acids containing three EF-hand calcium-binding domains, its expression level was highest in the mantle, hinting that the cgCaM gene is probably involved in shell formation of Pacific oyster, and the common ancestor of Gastropoda and Bivalvia may possess at least three CaM genes. We also found that the numbers of some EF hand family members in highly calcified species were higher than those in lowly calcified species and the numbers of these motifs in oyster genome were the highest among the mollusk species with whole genome sequence, further hinting the correlation between CaM and biomineralization. PMID:27703977

  2. Loss of an ecological baseline through the eradication of oyster reefs from coastal ecosystems and human memory.

    PubMed

    Alleway, Heidi K; Connell, Sean D

    2015-06-01

    Oyster reefs form over extensive areas and the diversity and productivity of sheltered coasts depend on them. Due to the relatively recent population growth of coastal settlements in Australia, we were able to evaluate the collapse and extirpation of native oyster reefs (Ostrea angasi) over the course of a commercial fishery. We used historical records to quantify commercial catch of O. angasi in southern Australia from early colonization, around 1836, to some of the last recorded catches in 1944 and used our estimates of catch and effort to map their past distribution and assess oyster abundance over 180 years. Significant declines in catch and effort occurred from 1886 to 1946 and no native oyster reefs occur today, but historically oyster reefs extended across more than 1,500 km of coastline. That oyster reefs were characteristic of much of the coastline of South Australia from 1836 to 1910 appears not to be known because there is no contemporary consideration of their ecological and economic value. Based on the concept of a shifted baseline, we consider this contemporary state to reflect a collective, intergenerational amnesia. Our model of generational amnesia accounts for differences in intergenerational expectations of food, economic value, and ecosystem services of nearshore areas. An ecological system that once surrounded much of the coast and possibly the past presence of oyster reefs altogether may be forgotten and could not only undermine progress towards their recovery, but also reduce our expectations of these coastal ecosystems.

  3. Role and value of nitrogen regulation provided by oysters (Crassostrea virginica) in the Mission-Aransas Estuary, Texas, USA.

    PubMed

    Beseres Pollack, Jennifer; Yoskowitz, David; Kim, Hae-Cheol; Montagna, Paul A

    2013-01-01

    Suspension-feeding activities of oysters impart a potentially significant benefit to estuarine ecosystems via reduction of water column nutrients, plankton and seston biomass, and primary productivity which can have a significant impact on human well-being. This study considered nitrogen regulation by eastern oysters Crassostrea virginica in the Mission-Aransas Estuary, Texas, USA, as a function of denitrification, burial, and physical transport from the system via harvest. Oyster reefs were estimated to remove 502.5 kg N km(-2) through denitrification of biodeposits and 251.3 kg N km(-2) in burial of biodeposits to sediments. Nitrogen is also physically transported out of the estuary via harvest of oysters. Commercial harvest of oysters in the Mission-Aransas Estuary can remove approximately 21,665 kg N per year via physical transport from the system. We developed a transferable method to value the service of nitrogen regulation by oysters, where the potential cost equivalent value of nitrogen regulation is quantified via cost estimates for a constructed biological nutrient removal (BNR) supplement to a wastewater treatment plant. The potential annual engineered cost equivalent of the service of nitrogen regulation and removal provided by reefs in the Mission-Aransas Estuary is $293,993 yr(-1). Monetizing ecosystem services can help increase awareness at the stakeholder level of the importance of oysters beyond commercial fishery values alone.

  4. Impacts of upstream drought and water withdrawals on the health and survival of downstream estuarine oyster populations

    PubMed Central

    Petes, Laura E; Brown, Alicia J; Knight, Carley R

    2012-01-01

    Increases in the frequency, duration, and severity of regional drought pose major threats to the health and integrity of downstream ecosystems. During 2007–2008, the U.S. southeast experienced one of the most severe droughts on record. Drought and water withdrawals in the upstream watershed led to decreased freshwater input to Apalachicola Bay, Florida, an estuary that is home to a diversity of commercially and ecologically important organisms. This study applied a combination of laboratory experiments and field observations to investigate the effects of reduced freshwater input on Apalachicola oysters. Oysters suffered significant disease-related mortality under high-salinity, drought conditions, particularly during the warm summer months. Mortality was size-specific, with large oysters of commercially harvestable size being more susceptible than small oysters. A potential salinity threshold was revealed between 17 and 25 ppt, where small oysters began to suffer mortality, and large oysters exhibited an increase in mortality. These findings have important implications for watershed management, because upstream freshwater releases could be carefully timed and allocated during stressful periods of the summer to reduce disease-related oyster mortality. Integrated, forward-looking water management is needed, particularly under future scenarios of climate change and human population growth, to sustain the valuable ecosystem services on which humans depend. PMID:22957175

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

    PubMed

    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.

  6. Molecular Cloning and Characterization of Full-Length cDNA of Calmodulin Gene from Pacific Oyster Crassostrea gigas.

    PubMed

    Li, Xing-Xia; Yu, Wen-Chao; Cai, Zhong-Qiang; He, Cheng; Wei, Na; Wang, Xiao-Tong; Yue, Xi-Qing

    2016-01-01

    The shell of the pearl oyster (Pinctada fucata) mainly comprises aragonite whereas that of the Pacific oyster (Crassostrea gigas) is mainly calcite, thereby suggesting the different mechanisms of shell formation between above two mollusks. Calmodulin (CaM) is an important gene for regulating the uptake, transport, and secretion of calcium during the process of shell formation in pearl oyster. It is interesting to characterize the CaM in oysters, which could facilitate the understanding of the different shell formation mechanisms among mollusks. We cloned the full-length cDNA of Pacific oyster CaM (cgCaM) and found that the cgCaM ORF encoded a peptide of 113 amino acids containing three EF-hand calcium-binding domains, its expression level was highest in the mantle, hinting that the cgCaM gene is probably involved in shell formation of Pacific oyster, and the common ancestor of Gastropoda and Bivalvia may possess at least three CaM genes. We also found that the numbers of some EF hand family members in highly calcified species were higher than those in lowly calcified species and the numbers of these motifs in oyster genome were the highest among the mollusk species with whole genome sequence, further hinting the correlation between CaM and biomineralization.

  7. Geologic controls on the recent evolution of oyster reefs in Apalachicola Bay and St. George Sound, Florida

    NASA Astrophysics Data System (ADS)

    Twichell, D.; Edmiston, L.; Andrews, B.; Stevenson, W.; Donoghue, J.; Poore, R.; Osterman, L.

    2010-07-01

    Apalachicola Bay and St. George Sound contain the largest oyster fishery in Florida, and the growth and distribution of the numerous oyster reefs here are the combined product of modern estuarine conditions in the bay and its late Holocene evolution. Sidescan-sonar imagery, bathymetry, high-resolution seismic profiles, and sediment cores show that oyster beds occupy the crests of a series of shoals that range from 1 to 7 km in length, trend roughly north-south perpendicular to the long axes of the bay and sound, and are asymmetrical with steeper sides facing to the west. Surface sediment samples show that the oyster beds consist of shelly sand, while much of the remainder of the bay floor is covered by mud delivered by the Apalachicola River. The present oyster reefs rest on sandy delta systems that advanced southward across the region between 6400 and 4400 yr BP when sea level was 4-6 m lower than present. Oysters started to colonize the region around 5100 yr BP and became extensive by 1200 and 2400 yr BP. Since 1200 yr BP, their aerial extent has decreased due to burial of the edges of the reefs by the prodelta mud that continues to be supplied by the Apalachicola River. Oyster reefs that are still active are narrower than the original beds, have grown vertically, and become asymmetrical in cross-section. Their internal bedding indicates they have migrated westward, suggesting a net westerly transport of sediment in the bay.

  8. Development and validation of a predictive model for the growth of Vibrio parahaemolyticus in post-harvest shellstock oysters.

    PubMed

    Parveen, Salina; DaSilva, Ligia; DePaola, Angelo; Bowers, John; White, Chanelle; Munasinghe, Kumudini Apsara; Brohawn, Kathy; Mudoh, Meshack; Tamplin, Mark

    2013-01-15

    Information is limited about the growth and survival of naturally-occurring Vibrio parahaemolyticus in live oysters under commercially relevant storage conditions harvested from different regions and in different oyster species. This study produced a predictive model for the growth of naturally-occurring V. parahaemolyticus in live Eastern oysters (Crassostrea virginica) harvested from the Chesapeake Bay, MD, USA and stored at 5-30 °C until oysters gapped. The model was validated with model-independent data collected from Eastern oysters harvested from the Chesapeake Bay and Mobile Bay, AL, USA and Asian (C. ariakensis) oysters from the Chesapeake Bay, VA, USA. The effect of harvest season, region and water condition on growth rate (GR) was also tested. At each time interval, two samples consisting of six oysters each were analyzed by a direct-plating method for total V. parahaemolyticus. The Baranyi D-model was fitted to the total V. parahaemolyticus growth and survival data. A secondary model was produced using the square root model. V. parahaemolyticus slowly inactivated at 5 and 10 °C with average rates of -0.002 and -0.001 log cfu/h, respectively. The average GRs at 15, 20, 25, and 30 °C were 0.038, 0.082, 0.228, and 0.219 log cfu/h, respectively. The bias and accuracy factors of the secondary model for model-independent data were 1.36 and 1.46 for Eastern oysters from Mobile Bay and the Chesapeake Bay, respectively. V. parahaemolyticus GRs were markedly lower in Asian oysters. Harvest temperature, salinity, region and season had no effect on GRs. The observed GRs were less than those predicted by the U.S. Food and Drug Administration's V. parahaemolyticus quantitative risk assessment.

  9. Smart-Geology for the World's largest fossil oyster reef

    NASA Astrophysics Data System (ADS)

    Dorninger, Peter; Nothegger, Clemens; Djuricic, Ana; Rasztovits, Sascha; Harzhauser, Mathias

    2014-05-01

    The geo-edutainment park "Fossilienwelt Weinviertel" at Stetten in Lower Austria exposes the world's largest fossil oyster biostrome. In the past decade, significant progress has been made in 3D digitizing sensor technology. To cope with the high amount of data, processing methods have been automated to a high degree. Consequently, we formulated the hypothesis that appropriate application of state-of-the-art 3D digitizing, data processing, and visualization technologies allows for a significant automation in paleontological prospection, making an evaluation of huge areas commercially feasible in both time and costs. We call the necessary processing steps "Smart Geology", being characterized by automation and large volumes of data. The Smart Geology project (FWF P 25883-N29) investigates three topics, 3D digitizing, automated geological and paleontological analysis and interpretation and finally investigating the applicability of smart devices for on-site accessibility of project data in order to support the two scientific hypotheses concerning the emerging process of the shell bed, i.e. was it formed by a tsunami or a major storm, and does it preserve pre- and post-event features. This contribution concentrates on the innovative and sophisticated 3D documentation and visualization processes being applied to virtualise approximately 15.000 fossil oysters at the approximately 25 by 17 m accessible shell bad. We decided to use a Terrestrial Laserscanner (TLS) for the determination of the geometrical 3D structures. The TLS achieves about 2 mm single point measurement accuracy. The scanning campaign provides a "raw" point cloud of approximately 1 bio. points at the respective area. Due to the scanning configuration used, the occurrence of occluded ares is minimized hence the full 3D structure of this unique site can be modelled. In addition, approximately 300 photos were taken with a nominal resolution of 0.6 mm per pixel. Sophisticated artificial lightning (close to

  10. Preliminary study of transplanting as a process for reducing levels of Vibrio vulnificus and Vibrio parahaemolyticus in shellstock oysters.

    PubMed

    Walton, William C; Nelson, Chris; Hochman, Mona; Schwarz, John

    2013-01-01

    Increasingly strict standards for harvest of oysters for the raw, half-shell market (designated as "white tag") should increase the proportion of oysters not meeting these standards (designated as "green tag"). Transplanting of green tag oysters into highsalinity waters (>20 practical salinity units) was explored as a means of returning Vibrio vulnificus and Vibrio parahaemolyticus levels to levels present on initial harvest. In summer 2011, oysters originally harvested in Louisiana were transplanted on two separate occasions (n = 2) to two sites in Mississippi Sound, AL: Sandy Bay and Dauphin Island. Oysters were tested for V. vulnificus and V. parahaemolyticus densities (by using the U.S. Food and Drug Administration enrichment method) after 2, 7, and 14 days deployed, with baseline samples taken (i) at the time of original harvest and iced, (ii) from oysters refrigerated within 1 h of harvest at <45°F ([7.2°C] white tag) and, (iii) from oysters not refrigerated during the harvest trip (green tag) but refrigerated after an 8-h trip. White and green tag oysters were sampled ∼24 h on arrival in Bon Secour, AL, put on ice, and shipped for analysis. Among baseline samples, there were no significant differences in V. vulnificus and V. parahaemolyticus densities, although the densities in the green tag oysters tended to be highest. After transplanting, V. vulnificus densities were significantly highest on day 2, with no significant differences among any of the other days within a site. On day 2, Sandy Bay had significantly greater densities of V. vulnificus than the Dauphin Island site, but no other days differed from time zero. For Vibrio parahaemolyticus, densities were greatest on day 2 and lowest at time zero, but this did not differ significantly from abundance on day 14. Average survival was 83.4% (± 3.13 SD), with no differences between sites. These preliminary results indicate that high-salinity transplanting could be an effective method of converting

  11. Regulation of Hox orthologues in the oyster Crassostrea gigas evidences a functional role for promoter DNA methylation in an invertebrate.

    PubMed

    Saint-Carlier, Emma; Riviere, Guillaume

    2015-06-04

    DNA methylation within promoter regions (PRDM) controls vertebrate early gene transcription and thereby development, but is neglected outside this group. However, epigenetic features in the oyster Crassostrea gigas suggest functional significance of PDRM in invertebrates. To investigate this, reporter constructs containing in vitro methylated oyster Hox gene promoters were transfected into oyster embryos. The influence of in vivo methylation was studied using bisulfite sequencing and DNA methyltransferase inhibition during development. Our results demonstrate that methylation controls the transcriptional activity of the promoters investigated, unraveling a functional role for PRDM in a lophotrochozoan, an important finding regarding the evolution of epigenetic regulation.

  12. [Pathogenic Vibrios in oysters (Crassostrea rhizophorae) served at restaurants in Rio de Janeiro: a public health warning].

    PubMed

    Pereira, Christiane Soares; Viana, Célio Mauro; Rodrigues, Dália dos Prazeres

    2007-01-01

    Forty oyster samples (Crassostrea rhizophorae) served raw in 15 restaurants in the city of Rio de Janeiro were evaluated in order to investigate the presence of Vibrio spp. The oyster samples were analyzed and subjected to enrichment in alkaline peptone water with the addition of 1 and 3% NaCl and incubated at 37 degrees C for 24 hours. Following this, the cultures were seeded onto thiosulfate citrate bile sucrose agar (TCBS) and the suspected colonies were subjected to biochemical characterization. Vibrio parahaemolyticus, Vibrio carchariae, Vibrio alginolyticus and Vibrio vulnificus were the main species (> 60%) isolated from raw oysters.

  13. Spermatogenesis in the rock oyster, Saccostrea forskali (Gmelin, 1791).

    PubMed

    Nuurai, Parinyaporn; Panasophonkul, Sasiporn; Tinikul, Yotsawan; Sobhon, Prasert; Wanichanon, Ratanasate

    2016-02-01

    Morphology of the differentiating spermatogenic cells of the rock oyster Saccostrea forskali (Bivalve: Ostreidae) was investigated by light and transmission electron microscopy. The testis is formed by several branching acini containing developing spermatogenic cells, classified into 7 stages based on nuclear characteristics, patterns of chromatin condensation and cytoplasmic contents. The spermatogonium is characterized by a euchromatic nucleus with a prominent nucleolus. The cytoplasm contains several round granulo-fibrillar dense bodies surrounded by numerous mitochondria. The round nucleus of the primary spermatocyte contains patches of electron-dense heterochromatin, numerous proacrosomal vesicles, ribosomes and mitochondria. The secondary spermatocytes contain a reticulated chromatin pattern and reduced number of proacrosomal vesicles. The early spermatids contain a small amount of euchromatin among dense patches of heterochromatin. A large single acrosomal vesicle is located in the posterior part of the cell. The middle spermatid is characterized by the migration of an acrosomal vesicle to the anterior part of the nucleus. The late spermatids contain highly condensed heterochromatin blocks and the acrosomal vesicle becomes cup-shaped and invaginated at the basal part. The spermatozoon contains a barrel-shaped head covered with the cup-like acrosome. At this stage, the subacrosomal space contains an axial rod in subacrosomal materials. Three to four transverse bands appear at the anterior region of the acrosome. The middle piece consists of spherical mitochondria surrounding the proximal and distal centrioles. The flagellum consists of 9+2 axonemal microtubule doublets surrounded by the plasma membrane. Our electron microscopic study of spermatogenesis in the S. forskali provides important new information on the mechanism of development of spermatogenesis of this species.

  14. Giant Upper Cretaceous oysters from the Gulf coast and Caribbean

    USGS Publications Warehouse

    Sohl, Norman F.; Kauffman, Erle G.

    1964-01-01

    Two unusually massive ostreid species, representing the largest and youngest Mesozoic members of their respective lineages, occur in Upper Cretaceous sediment of the gulf coast and Caribbean areas. Their characteristics and significance, as well as the morphologic terminology of ostreids in general, are discussed. Crassostrea cusseta Sohl and Kauffman n. sp. is the largest known ostreid from Mesozoic rocks of North America; it occurs sporadically in the Cusseta Sand and rarely in the Blufftown Formation of the Chattahoochee River region in Georgia and Alabama. It is especially notable in that it lacks a detectable posterior adductor muscle scar on large adult shells. C. cusseta is the terminal Cretaceous member of the C. soleniscus lineage in gulf coast sediments; the lineage continues, however, with little basic modification, throughout the Cenozoic, being represented in the Eocene by C. gigantissima (Finch) and probably, in modern times, by C. virginica (Gmelin). The C. soleniscus lineage is the first typically modern crassostreid group recognized in the Mesozoic. Arctostrea aguilerae (Böse) occurs in Late Campanian and Early Maestrichtian sediments of Alabama, Mississippi, Texas(?), Mexico, and Cuba. The mature shell of this species is larger and more massive than that of any other known arctostreid. Arctostrea is well represented throughout the Upper Jurassic and Cretaceous of Europe, but in North America, despite the great numbers and diversity of Cretaceous oysters, only A. aguilerae and the Albian form A. carinata are known. The presence of A. aquilerae in both the Caribbean and gulf coast faunas is exceptional, as the Late Cretaceous faunas of these provinces are generally distinct and originated in different faunal realms.

  15. Bacillus crassostreae sp. nov., isolated from an oyster (Crassostrea hongkongensis).

    PubMed

    Chen, Jin-Hua; Tian, Xiang-Rong; Ruan, Ying; Yang, Ling-Ling; He, Ze-Qiang; Tang, Shu-Kun; Li, Wen-Jun; Shi, Huazhong; Chen, Yi-Guang

    2015-05-01

    A novel Gram-stain-positive, motile, catalase- and oxidase-positive, endospore-forming, facultatively anaerobic rod, designated strain JSM 100118(T), was isolated from an oyster (Crassostrea hongkongensis) collected from the tidal flat of Naozhou Island in the South China Sea. Strain JSM 100118(T) was able to grow with 0-13% (w/v) NaCl (optimum 2-5%), at pH 5.5-10.0 (optimum pH 7.5) and at 5-50 °C (optimum 30-35 °C). The cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. The predominant respiratory quinone was menaquinone-7 and the major cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0, C16 : 0 and C16 : 1ω11c. The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unknown glycolipid and an unknown phospholipid. The genomic DNA G+C content was 35.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JSM 100118(T) belonged to the genus Bacillus , and was most closely related to Bacillus litoralis SW-211(T) (98.9% 16S rRNA gene sequence similarity), Bacillus halosaccharovorans E33(T) (98.3%), Bacillus niabensis 4T19(T) (97.8%) and Bacillus herbersteinensis D-1,5a(T) (97.1%). The combination of results from the phylogenetic analysis, DNA-DNA hybridization, and phenotypic and chemotaxonomic characterization supported the conclusion that strain JSM 100118(T) represents a novel species of the genus Bacillus , for which the name Bacillus crassostreae sp. nov. is proposed. The type strain is JSM 100118(T) ( = CTCC AB 2010452(T) =DSM 24486(T) =JCM 17523(T)).

  16. Sequence Polymorphism and Expression Variability of Crassostrea gigas Immune Related Genes Discriminate Two Oyster Lines Contrasted in Term of Resistance to Summer Mortalities

    PubMed Central

    Schmitt, Paulina; Santini, Adrien; Vergnes, Agnès; Degremont, Lionel; de Lorgeril, Julien

    2013-01-01

    Summer mortalities of Crassostreagigas are a major concern in oyster aquaculture. They are the result of a complex interaction between the host, pathogens and environmental factors. Oyster genetics have been identified as an essential determinant of oyster susceptibility to summer mortalities. As the capability of oysters to circumvent diseases depends in part on their immune defenses, we aimed to analyze the gene expression and sequence polymorphism of 42 immune related genes in two oyster lines selected for their “High” (H) and “Low” (L) survival to summer mortalities. Results showed that the variability of gene expression and the sequence polymorphism acting on particular genes could enable the discrimination between H and L oyster lines. Besides, a higher sequence polymorphism was observed on the L line affecting 11 of the 42 analyzed genes. By analyzing gene expression, sequence polymorphism and gene copy number of two antimicrobial peptide families (Cg-Defs and Cg-Prp), and an antimicrobial protein (Cg-BPI) on individual oysters, we showed that gene expression and/or sequence polymorphism could also discriminate H and L oyster lines. Finally, we observed a positive correlation between the gene expression and the gene copy number of antimicrobials and that sequence polymorphism could be encoded in the genome. Overall, this study gives new insights in the relationship between oyster immunity and divergent phenotypes, and discusses the potential implication of antimicrobial diversity in oyster survival to summer mortalities. PMID:24086661

  17. Sequence polymorphism and expression variability of Crassostrea gigas immune related genes discriminate two oyster lines contrasted in term of resistance to summer mortalities.

    PubMed

    Schmitt, Paulina; Santini, Adrien; Vergnes, Agnès; Degremont, Lionel; de Lorgeril, Julien

    2013-01-01

    Summer mortalities of Crassostreagigas are a major concern in oyster aquaculture. They are the result of a complex interaction between the host, pathogens and environmental factors. Oyster genetics have been identified as an essential determinant of oyster susceptibility to summer mortalities. As the capability of oysters to circumvent diseases depends in part on their immune defenses, we aimed to analyze the gene expression and sequence polymorphism of 42 immune related genes in two oyster lines selected for their "High" (H) and "Low" (L) survival to summer mortalities. Results showed that the variability of gene expression and the sequence polymorphism acting on particular genes could enable the discrimination between H and L oyster lines. Besides, a higher sequence polymorphism was observed on the L line affecting 11 of the 42 analyzed genes. By analyzing gene expression, sequence polymorphism and gene copy number of two antimicrobial peptide families (Cg-Defs and Cg-Prp), and an antimicrobial protein (Cg-BPI) on individual oysters, we showed that gene expression and/or sequence polymorphism could also discriminate H and L oyster lines. Finally, we observed a positive correlation between the gene expression and the gene copy number of antimicrobials and that sequence polymorphism could be encoded in the genome. Overall, this study gives new insights in the relationship between oyster immunity and divergent phenotypes, and discusses the potential implication of antimicrobial diversity in oyster survival to summer mortalities.

  18. DNA barcoding reveals that the common cupped oyster in Taiwan is the Portuguese oyster Crassostrea angulata (Ostreoida; Ostreidae), not C. gigas.

    PubMed

    Hsiao, Sheng-Tai; Chuang, Shin-Chang; Chen, Kao-Sung; Ho, Ping-Ho; Wu, Chi-Lun; Chen, Chaolun Allen

    2016-09-26

    The Pacific cupped oyster, Crassostrea gigas, is one of the major aquacultural shellfish species that has been introduced to Europe and America from its native source in the West Pacific. In Taiwan, the cultivated cupped oysters along the west coast have been identified as C. gigas for over centuries; however, several molecular phylogenetic studies have cast doubt upon the existence of this species in Taiwan and adjacent waters. Indeed, our analyses of mitochondrial cytochrome oxidase I (COI) sequences from 313 Crassostrea collected from 12 locations along Taiwanese and southern Chinese coastlines confirm that all samples were the Portuguese oyster, C. angulata, rather than C. gigas. Multiple lines of evidence, including haplotypic and nucleotide diversity of the COI gene, demographic history, and population genetics, suggest that Taiwanese C. angulata is unique, probably experienced a sudden population expansion after the Last Glacial Maxima around 20,000 years ago, and has a significantly limited genetic connectivity across the Taiwan Strait. Our study applies an extended sampling and DNA barcoding to confirm the absence of C. gigas in natural and cultivated populations in Taiwan and southern China, where we only found C. angulata. We highlight the importance of conserving the gene pool of the C. angulata population in Taiwan, particularly considering the current threats by large-scale environmental disturbances such as marine pollution, habitat destruction, and climate change.

  19. DNA barcoding reveals that the common cupped oyster in Taiwan is the Portuguese oyster Crassostrea angulata (Ostreoida; Ostreidae), not C. gigas

    NASA Astrophysics Data System (ADS)

    Hsiao, Sheng-Tai; Chuang, Shin-Chang; Chen, Kao-Sung; Ho, Ping-Ho; Wu, Chi-Lun; Chen, Chaolun Allen

    2016-09-01

    The Pacific cupped oyster, Crassostrea gigas, is one of the major aquacultural shellfish species that has been introduced to Europe and America from its native source in the West Pacific. In Taiwan, the cultivated cupped oysters along the west coast have been identified as C. gigas for over centuries; however, several molecular phylogenetic studies have cast doubt upon the existence of this species in Taiwan and adjacent waters. Indeed, our analyses of mitochondrial cytochrome oxidase I (COI) sequences from 313 Crassostrea collected from 12 locations along Taiwanese and southern Chinese coastlines confirm that all samples were the Portuguese oyster, C. angulata, rather than C. gigas. Multiple lines of evidence, including haplotypic and nucleotide diversity of the COI gene, demographic history, and population genetics, suggest that Taiwanese C. angulata is unique, probably experienced a sudden population expansion after the Last Glacial Maxima around 20,000 years ago, and has a significantly limited genetic connectivity across the Taiwan Strait. Our study applies an extended sampling and DNA barcoding to confirm the absence of C. gigas in natural and cultivated populations in Taiwan and southern China, where we only found C. angulata. We highlight the importance of conserving the gene pool of the C. angulata population in Taiwan, particularly considering the current threats by large-scale environmental disturbances such as marine pollution, habitat destruction, and climate change.

  20. The late Cenomanian oyster Lopha staufferi (Bergquist, 1944) - the oldest ribbed oyster in the Upper Cretaceous of the Western Interior of the United States

    NASA Astrophysics Data System (ADS)

    Hook, Stephen C.; Cobban, William A.

    2016-12-01

    Lopha staufferi (Bergquist, 1944) is a medium-sized, ribbed, Late Cretaceous oyster with a slightly curved axis and a zigzag commissure; it appears suddenly and conspicuously in upper Cenomanian rocks in the Western Interior Basin of the United States. At maturity, the ribs on both valves thicken into steep flanks that allow the oyster to increase interior volume without increasing its exterior footprint on the seafloor. Lopha staufferi is the first (earliest) ribbed oyster in the Late Cretaceous of the Western Interior, but has no ancestor in the basin. It disappears from the rock record as suddenly as it appeared, leaving no direct descendent in the basin. In the southern part of the basin where it is well constrained, L. staufferi is restricted stratigraphically to the upper Cenomanian Metoicoceras mosbyense Zone (= Dunveganoceras conditum Zone in the north). Lopha staufferi has an unusual paleogeographic distribution, occurring in only two, widely scattered areas in the basin. It has been found at several localities near the western shoreline of the Late Cretaceous Seaway in west-central New Mexico and adjacent Arizona, and in localities 1,900 km (1,200 mi) to the northeast near the eastern shoreline in northeastern Minnesota, but nowhere in between. In west-central New Mexico and adjacent Arizona, L. staufferi is a guide fossil to the Twowells Tongue of the Dakota Sandstone.