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.

Effects of pre- or post-processing storage conditions on high-hydrostatic pressure inactivation of Vibrio parahaemolyticus and V. vulnificus in oysters.

PubMed

Ye, Mu; Huang, Yaoxin; Gurtler, Joshua B; Niemira, Brendan A; Sites, Joseph E; Chen, Haiqiang

2013-05-15

The effects of storage conditions on subsequent high-hydrostatic pressure (HHP) inactivation of Vibrio parahaemolyticus and Vibrio vulnificus in oysters were investigated. Live oysters were inoculated with V. parahaemolyticus or V. vulnificus to ca. 7-8 log MPN/g by feeding and stored at varying conditions (i.e., 21 or 35 °C for 5h, 4 or 10 °C for 1 and 2 days and -18 °C for 2 weeks). Oyster meats were then treated at 225-300 MPa for 2 min at 4, 21 or 35 °C. HHP at 300 MPa for 2 min achieved a >5-log MPN/g reduction of V. parahaemolyticus, completely inactivating V. vulnificus (negative by enrichment) in oysters. Treatment temperatures of 4, 21 and 35 °C did not significantly affect pressure inactivation of V. parahaemolyticus or V. vulnificus (P>0.05). Cold storage at -18, 4 and 10 °C, prior to HHP, decreased V. parahaemolyticus or V. vulnificus populations by 1.5-3.0 log MPN/g, but did not increase their sensitivity to subsequent HHP treatments. The effects of cold storage after HHP on inactivation of V. parahaemolyticus in oysters were also determined. Oysters were inoculated with V. parahaemolyticus and stored at 21 °C for 5h or 4 °C for 1 day. Oyster meats were then treated at 250-300 MPa for 2 min at 21 or 35 °C and stored for 15 days in ice or in a freezer. V. parahaemolyticus populations in HHP-treated oysters gradually decreased during post-HHP ice or frozen storage. A validation study using whole-shell oysters was conducted to determine whether the presence of oyster shells influenced HHP inactivation of V. parahaemolyticus. No appreciable differences in inactivation between shucked oyster meat and whole-shell oysters were observed. HPP at 300 MPa for 2 min at 21 °C, followed by 5-day ice storage or 7-day frozen storage, and HPP at 250 MPa for 2 min at 21 °C, followed by 10-day ice or 7-day frozen storage, completely inactivated V. parahaemolyticus in whole-shell oysters (>7 log reductions). The combination of HHP at a relatively low pressure

Efficacy of petal fall and shuck split fungicides for control of scab on peach in middle Georgia, 2012

USDA-ARS?s Scientific Manuscript database

Fungicides were evaluated for control of scab in a mid-ripening experimental peach block (‘Flameprince’) located at the USDA-ARS Fruit and Tree Nut Research Laboratory (Byron, GA). Chemical formulations were applied at each application date: 3 Apr (petal fall to 1% shuck split), 10 Apr (shuck split ...

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 are...

An Analysis of Denitrification and Anammox Processes in Sediments Underneath Oyster Aquaculture

NASA Astrophysics Data System (ADS)

Mazur, C. I.; Edgcomb, V. P.; Rogers, D.; Cobban, A.

2016-02-01

Oysters play a very important role in the removal of nitrogen from eutrophic waters. While the amount of nitrogen that is converted into biomass is well studied, little is known about the additional amount of nitrogen that may be removed from the sediments due to the presence of oysters. The purpose of this project was to examine microbial processes that occur in sediments under oyster aquaculture cages in local ponds/estuaries, and to measure the rates of key processes associated with nitrogen removal. Little Pond and West Falmouth (Cape Cod, Massachusetts) are coastal waterways that are degraded due to nitrogen loading. Oyster aquaculture operations have been installed at both sites to help clean up those eutrophic estuaries. We measured nitrate and ammonia concentrations in porewaters and water columns. Direct measurements of rates of denitrification and anaerobic ammonium oxidation (anammox) were completed with Membrane Inlet Mass Spectroscopy (MIMS). Genes and transcripts associated with denitrification and anammox in sediments under oysters and at control sites were calculated using quantitative PCR. Results suggest that rates of denitrification are 2-30 times higher under oysters than at control sites, and gene expression patterns provide a second line of support for those findings. The ultimate goal of the project is to provide data to improve models of the nitrogen removal potential of shellfish aquaculture as a possible remediation strategy for improving the quality of eutrophic coastal waters.

High pressure processing inactivates human norovirus within oysters

USDA-ARS?s Scientific Manuscript database

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...

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

USDA-ARS?s Scientific Manuscript database

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...

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

... Safety Zone, Oyster Festival 30th Anniversary Fireworks Display, Oyster Bay; Oyster Bay, NY AGENCY: Coast... zone on the navigable waters of Oyster Bay near Oyster Bay, NY for the Oyster Festival 30th Anniversary... Oyster Festival 30th Anniversary Fireworks Display is scheduled for October 19, 2013 and is one of...

Gear and survey efficiency of patent tongs for oyster populations on restoration reefs.

PubMed

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

2018-01-01

Surveys of restored oyster reefs need to produce accurate population estimates to assess the efficacy of restoration. Due to the complex structure of subtidal oyster reefs, one effective and efficient means to sample is by patent tongs, rather than SCUBA, dredges, or bottom cores. Restored reefs vary in relief and oyster density, either of which could affect survey efficiency. This study is the first to evaluate gear (the first full grab) and survey (which includes selecting a specific half portion of the first grab for further processing) efficiencies of hand-operated patent tongs as a function of reef height and oyster density on subtidal restoration reefs. In the Great Wicomico River, a tributary of lower Chesapeake Bay, restored reefs of high- and low-relief (25-45 cm, and 8-12 cm, respectively) were constructed throughout the river as the first large-scale oyster sanctuary reef restoration effort (sanctuary acreage > 20 ha at one site) in Chesapeake Bay. We designed a metal frame to guide a non-hydraulic mechanical patent tong repeatedly into the same plot on a restored reef until all oysters within the grab area were captured. Full capture was verified by an underwater remotely-operated vehicle. Samples (n = 19) were taken on nine different reefs, including five low- (n = 8) and four high-relief reefs (n = 11), over a two-year period. The gear efficiency of the patent tong was estimated to be 76% (± 5% standard error), whereas survey efficiency increased to 81% (± 10%) due to processing. Neither efficiency differed significantly between young-of-the-year oysters (spat) and adults, high- and low-relief reefs, or years. As this type of patent tong is a common and cost-effective tool to evaluate oyster restoration projects as well as population density on fished habitat, knowing the gear and survey efficiencies allows for accurate and precise population estimates.

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). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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. Copyright © 2013 Elsevier B.V. All rights reserved.

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.

Randomized, double-blinded clinical trial for human norovirus inactivation in oysters by high hydrostatic pressure processing.

PubMed

Leon, Juan S; Kingsley, David H; Montes, Julia S; Richards, Gary P; Lyon, G Marshall; Abdulhafid, Gwen M; Seitz, Scot R; Fernandez, Marina L; Teunis, Peter F; Flick, George J; Moe, Christine L

2011-08-01

Contamination of oysters with human noroviruses (HuNoV) constitutes a human health risk and may lead to severe economic losses in the shellfish industry. There is a need to identify a technology that can inactivate HuNoV in oysters. In this study, we conducted a randomized, double-blinded clinical trial to assess the effect of high hydrostatic pressure processing (HPP) on Norwalk virus (HuNoV genogroup I.1) inactivation in virus-seeded oysters ingested by subjects. Forty-four healthy, positive-secretor adults were divided into three study phases. Subjects in each phase were randomized into control and intervention groups. Subjects received Norwalk virus (8FIIb, 1.0 × 10(4) genomic equivalent copies) in artificially seeded oysters with or without HPP treatment (400 MPa at 25°C, 600 MPa at 6°C, or 400 MPa at 6°C for 5 min). HPP at 600 MPa, but not 400 MPa (at 6° or 25°C), completely inactivated HuNoV in seeded oysters and resulted in no HuNoV infection among these subjects, as determined by reverse transcription-PCR detection of HuNoV RNA in subjects' stool or vomitus samples. Interestingly, a white blood cell (granulocyte) shift was identified in 92% of the infected subjects and was significantly associated with infection (P = 0.0014). In summary, these data suggest that HPP is effective at inactivating HuNoV in contaminated whole oysters and suggest a potential intervention to inactivate infectious HuNoV in oysters for the commercial shellfish industry.

Efficacy of low-temperature high hydrostatic pressure processing in inactivating Vibrio parahaemolyticus in culture suspension and oyster homogenate.

PubMed

Phuvasate, Sureerat; Su, Yi-Cheng

2015-03-02

Culture suspensions of five clinical and five environmental Vibrio parahaemolyticus strains in 2% NaCl solution were subjected to high pressure processing (HPP) under various conditions (200-300MPa for 5 and 10 min at 1.5-20°C) to study differences in pressure resistance among the strains. The most pressure-resistant and pressure-sensitive strains were selected to investigate the effects of low temperatures (15, 5 and 1.5°C) on HPP (200 or 250MPa for 5 min) to inactivate V. parahaemolyticus in sterile oyster homogenates. Inactivation of V. parahaemolyticus cells in culture suspensions and oyster homogenates was greatly enhanced by lowering the processing temperature from 15 to 5 or 1.5°C. A treatment of oyster homogenates at 250MPa for 5 min at 5°C decreased the populations of V. parahaemolyticus by 6.2logCFU/g for strains 10290 and 100311Y11 and by >7.4logCFU/g for strain 10292. Decreasing the processing temperature of the same treatment to 1.5°C reduced all the V. parahaemolyticus strains inoculated to oyster homogenates to non-detectable (<10CFU/g) levels. Factors including pressure level, processing temperature and time all need to be considered for developing effective HPP for eliminating pathogens from foods. Further studies are needed to validate the efficacy of the HPP (250MPa for 5 min at 1.5°C) in inactivating V. parahaemolyticus cells in whole oysters. Copyright © 2014 Elsevier B.V. All rights reserved.

The hot oyster: levels of virulent Vibrio parahaemolyticus strains in individual oysters.

PubMed

Klein, Savannah L; Lovell, Charles R

2017-02-01

Vibrio parahaemolyticus is the leading cause of seafood-associated gastroenteritis and is most commonly transmitted by raw oysters. Consequently, detection of virulent strains of this organism in oysters is a primary concern for seafood safety. Vibrio parahaemolyticus levels were determined in 110 individual oysters harvested from two sampling sites in SC, USA. The majority of oysters (98%) contained low levels of presumptive V. parahaemolyticus However, two healthy oysters contained presumptive V. parahaemolyticus numbers that were unusually high. These two 'hot' oysters contained levels of presumptive V. parahaemolyticus within the gills that were ∼100-fold higher than the average for other oysters collected at the same date and location. Current V. parahaemolyticus detection practices require homogenizing a dozen oysters pooled together to determine V. parahaemolyticus numbers, a procedure that would dilute out V. parahaemolyticus in these 'hot' oysters. This study demonstrates the variability of V. parahaemolyticus densities taken from healthy, neighboring individual oysters in the environment. Additionally, environmental V parahaemolyticus isolates were screened for the virulence-related genes, tdh and trh, using improved polymerase chain reaction primers and protocols. We detected these genes, previously thought to be rare in environmental isolates, in approximately half of the oyster isolates. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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.

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)

Does restoring oyster reefs restore oyster health?

USDA-ARS?s Scientific Manuscript database

American colonists found native oyster reefs so plentiful that oysters, with tobacco and spirits, completed the triumvirate of necessities, and their discarded shells paved the earliest colonial streets from New England down to the Gulf Coast. Industrialization and dredging, however, had devastating...

High salinity relay as a post-harvest processing method for reducing Vibrio vulnificus levels in oysters (Crassostrea virginica).

PubMed

Audemard, Corinne; Kator, Howard I; Reece, Kimberly S

2018-08-20

High salinity relay of Eastern oysters (Crassostrea virginica) was evaluated as a post-harvest processing (PHP) method for reducing Vibrio vulnificus. This approach relies on the exposure of oysters to natural high salinity waters and preserves a live product compared to previously approved PHPs. Although results of prior studies evaluating high salinity relay as a means to decrease V. vulnificus levels were promising, validation of this method as a PHP following approved guidelines is required. This study was designed to provide data for validation of this method following Food and Drug Administration (FDA) PHP validation guidelines. During each of 3 relay experiments, oysters cultured from 3 different Chesapeake Bay sites of contrasting salinities (10-21 psu) were relayed without acclimation to high salinity waters (31-33 psu) for up to 28 days. Densities of V. vulnificus and densities of total and pathogenic Vibrio parahaemolyticus (as tdh positive strains) were measured using an MPN-quantitative PCR approach. Overall, 9 lots of oysters were relayed with 6 exhibiting initial V. vulnificus >10,000/g. As recommended by the FDA PHP validation guidelines, these lots reached both the 3.52 log reduction and the <30 MPN/g densities requirements for V. vulnificus after 14 to 28 days of relay. Densities of total and pathogenic V. parahaemolyticus in relayed oysters were significantly lower than densities at the sites of origin suggesting an additional benefit associated with high salinity relay. While relay did not have a detrimental effect on oyster condition, oyster mortality levels ranged from 2 to 61% after 28 days of relay. Although the identification of the factors implicated in oyster mortality will require further examination, this study strongly supports the validation of high salinity relay as an effective PHP method to reduce levels of V. vulnificus in oysters to endpoint levels approved for human consumption. Copyright © 2018 Elsevier B.V. All

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

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

The Removal of Turbidity and TSS of the Domestic Wastewater by Coagulation-Flocculation Process Involving Oyster Mushroom as Biocoagulant

NASA Astrophysics Data System (ADS)

Pardede, Astrid; Budihardjo, Mochamad Arief; Purwono

2018-02-01

Oyster mushroom (Pleurotus ostreatus) can be utilized as biocoagulant since it has chitin cell wall. Chitin has characteristics of bioactivity, biodegradability, absorption and could bind the metal ions. In this study, Oyster Mushroom is micronized and mixed with wastewater to treat turbidity and Total Suspended Solid (TSS) using coagulation-flocculation process employed jartest method. Various doses of Oyster mushroom, 600 mg/l, 1000 mg/l, and 2000 mg/l were tested in several rapid mixing rates which were 100 rpm, 125 rpm, and 150 rpm for 3 minutes followed by 12 minutes of slow mixing at 45 rpm. The mixture then was settled for 60 minutes with pH level maintained at 6-8. The result showed that the Oyster mushroom biocoagulant was able to remove 84% of turbidity and 90% of TSS. These reductions were achieved with biocoagulant dose of 600 mg/ L at 150 rpm mixing rate.

Virus, protozoa and organic compounds decay in depurated oysters.

PubMed

Souza, Doris Sobral Marques; Piazza, Rômi Sharon; Pilotto, Mariana Rangel; do Nascimento, Mariana de Almeida; Moresco, Vanessa; Taniguchi, Satie; Leal, Diego Averaldo Guiguet; Schmidt, Éder der Carlos; Cargin-Ferreira, Eduardo; Bícego, Márcia Caruso; Sasaki, Silvio Tarou; Montone, Rosalinda Carmela; de Araujo, Rafael Alves; Franco, Regina Maura Bueno; Bouzon, Zenilda Laurita; Bainy, Afonso Celso Dias; Barardi, Célia Regina Monte

2013-11-01

(1) Evaluate the dynamic of the depuration process of Crassostrea gigas oysters using different ultraviolet doses with different amounts of contaminants (virus, protozoa and organic contaminants) and (2) investigate the morphological changes in the oysters' tissues produced by the depuration procedures. The oysters were allocated in sites with different degrees of contamination and analyzed after 14 days. Some animals were used as positive controls by artificial bioaccumulation with HAdV2 and MNV1 and subjected to depuration assays using UV lamps (18 or 36 W) for 168 h. The following pollutants were researched in the naturally contaminated oysters, oysters after 14 days in sites and oysters during the depuration processes: virus (HAdV, HAV, HuNoV GI/GII and JCPyV), by (RT) qPCR; protozoa (Cryptosporidium and Giardia species), by immunomagnetic separation and immunofluorescence; and organic compounds (AHs, PAHs, LABs, PCBs and organochlorine pesticides-OCs), by chromatography. Changes in the oysters' tissues produced by the depuration processes were also evaluated using histochemical analysis by light microscopy. In the artificially bioaccumulated oysters, only HAdV2 and MNV1 were investigated by (RT) qPCR before the depuration procedures and after 96 and 168 h of these procedures. At 14 days post-allocation, HAdV was found in all the sites (6.2 × 105 to 4.4 × 107 GC g(-1)), and Giardia species in only one site. Levels of PCBs and OCs in the oyster's tissues were below the detection limit for all samples. AHs (3.5 to 4.4 μg g(-1)), PAHs (11 to 191 ng g(-1)) and LABs (57 to 751 ng g(-1)) were detected in the samples from 3 sites. During the depuration assays, we found HAdV, Giardia and Cryptosporidium species until 168 h, independent of UV treatment. AHs, PAHs and LABs were found also after 168 h of depuration (36 W and without UV lamp). The depuration procedures did not produce changes in the oysters' tissues. In the artificially contaminated and depurated

Putting oysters under pressure

USDA-ARS?s Scientific Manuscript database

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...

Human norovirus inactivation in oysters by high hydrostatic pressure processing: A randomized double-blinded study

USDA-ARS?s Scientific Manuscript database

This randomized, double-blinded, clinical trial assessed the effect of high hydrostatic pressure processing (HPP) on genogroup I.1 human norovirus (HuNoV) inactivation in virus-seeded oysters when ingested by subjects. The safety and efficacy of HPP treatments were assessed in three study phases wi...

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.

Flow-sediment-oyster interaction around degraded, restored, and reference oyster reefs in Florida's Indian River Lagoon

NASA Astrophysics Data System (ADS)

Kitsikoudis, V.; Kibler, K. M.; Spiering, D. W.

2017-12-01

This study analyzes flow patterns and sediment distributions around three oyster reefs in a bar-built estuarine lagoon. We studied a degraded reef, a recently restored reef, and a reference condition reef with a healthy live oyster community. The restored reef had been regraded and restored with oyster shell mats to aid in recruitment of oyster spat, with the goal of reestablishing a healthy oyster community. Despite the fact that flow-biota-sediment interaction constitutes a blossoming research field, actual field data are sparse and current knowledge emanates from flume studies and numerical modeling. Moreover, the hydraulic effect of restored oyster reefs has not been thoroughly investigated and it is not clear if the flow field and sediment erosion/deposition are similar or diverge from natural reefs. Instantaneous three-dimensional flow velocities were collected on reefs using a Nortek Vectrino Profiler and an acoustic Doppler current profiler (Nortek Aquadopp). The former measured a 2 - 3 cm velocity profile above the oyster bed, while the latter quantified incoming velocities across the flow profile approximately 10 m from the edge of the reef. Flow measurements were conducted during rising tides and are coupled with simultaneous wind speed and direction data. In addition, 20 cm deep sediment cores were retrieved on and off the investigated reefs. Sediment grain size distributions were determined after individual cores were processed for loss on ignition. Incoming flow velocities were as high as 10 cm/s, relatively higher than those recorded close to reefs. Mean and turbulent flow velocities close to the reefs, varied among the investigated sites, despite the similar wind flow conditions offshore. For instance, the measurements at the degraded reef showed decreased wave attenuation and augmented flow velocities compared to the other sites. Boat wakes exhibited a very distinct signal in the flow velocity time-series and significantly increased the approaching

Effects of Substerilization Doses of Co60 Gamma Radiation on the Cold-Storage Life Extension of Shucked Soft-Shelled Clams and Haddock Fillets

PubMed Central

Masurovsky, E. B.; Goldblith, S. A.; Nickerson, J. T. R.

1963-01-01

Total aerobic-facultative and anaerobic (clostridia) macrocolony count data are presented, with analysis and interpretation, for both haddock fillets and shucked soft-shelled clams which received doses of from 50,000 to 800,000 rad of Co60 gamma rays. These data indicated that haddock fillets may be maintained in good condition at refrigeration temperatures above freezing for about 1 week at 6 C, and approximately 2 weeks at 0 C, when treated with from 50,000 to 150,000 rad of ionizing radiation. In the dose range from 200,000 to 350,000 rad, the storage life may be extended up to some 2 weeks at 6 C, and 3 weeks at 0 C. Treatments in the dose range from 400,000 to 500,000 rad may defer spoilage for about 1 month, and doses of 550,000 to 650,000 rad afford protection against bacterial spoilage up to approximately 1.5 months. At the high substerilization doses of 700,000 to 800,000 rad, haddock fillets may be held for from 2 to 3 months in refrigerated storage before becoming unfit for marketing and consumption. Shucked soft-shelled clams can be held for about 2.5 weeks at 0 C and close to 12 days at 6 C, when given low substerilization doses of from 50,000 to 150,000 rad of ionizing radiation. At doses of from 200,000 to 350,000 rad, the clams may be preserved effectively for periods up to 3 weeks at 0 or 6 C, and some 6 weeks at these temperatures with doses of about 450,000 rad. With treatments of 500,000 to 600,000 rad, the storage life may be extended for some 2 months, and at doses of 650,000 to 800,000 rad the shucked clams remain in a good state of preservation for up to 3 months at temperatures of 0 to 6 C. Thus, it would appear that shucked soft-shelled clams may be maintained for significantly longer periods in refrigerated storage than haddock fillets when the same radiation treatments are applied to each product. Clostridia levels in both products were relatively low initially, and were reduced significantly by the gamma rays at the doses studied

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.

High salinity relay as a postharvest processing strategy to reduce vibrio vulnificus levels in Chesapeake Bay oysters (Crassostrea virginica).

PubMed

Audemard, Corinne; Kator, Howard I; Rhodes, Martha W; Gallivan, Thomas; Erskine, A J; Leggett, A Thomas; Reece, Kimberly S

2011-11-01

In 2009 the U.S. Food and Drug Administration (FDA) announced its intention to implement postharvest processing (PHP) methods to eliminate Vibrio vulnificus from oysters intended for the raw, half-shell market that are harvested from the Gulf of Mexico during warmer months. FDA-approved PHP methods can be expensive and may be associated with unfavorable responses from some consumers. A relatively unexplored PHP method that uses relaying to high salinity waters could be an alternative strategy, considering that high salinities appear to negatively affect the survival of V. vulnificus. During relay, however, oysters may be exposed to rapid and large salinity increases that could cause increased mortality. In this study, the effectiveness of high salinity relay to reduce V. vulnificus to <30 most probable number (MPN) per g and the impact on oyster mortality were assessed in the lower Chesapeake Bay. Two relay experiments were performed during the summer and fall of 2010. Oysters collected from three grow-out sites, a low salinity site (14 to 15 practical salinity units [psu]) and two moderate salinity sites (22 to 25 psu), were relayed directly to a high salinity site (≥30 psu) on Virginia's Eastern Shore. Oysters were assayed for V. vulnificus and Vibrio parahaemolyticus (another Vibrio species of concern) densities at time 0 prior to relay and after 7 and 14 days of relay, using the FDA MPN enrichment method combined with detection by real-time PCR. After 14 days, both V. vulnificus and V. parahaemolyticus densities were ≤0.8 MPN/g, and decreases of 2 to 3 log in V. vulnificus densities were observed. Oyster mortalities were low (≤4%) even for oysters from the low salinity harvest site, which experienced a salinity increase of approximately 15 psu. Results, although preliminary and requiring formal validation and economic analysis, suggest that high salinity relay could be an effective PHP method.

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 oyster...

Surveying a fossil oyster reef using terrestrial laser scanning

NASA Astrophysics Data System (ADS)

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

2009-04-01

is suitable for answering certain questions of paleontologists and geologists. Finally, structural measurements may be performed in a geological software application, without treading on the fragile surface. On the other hand, paleontologists are interested in knowing if the oyster axes are aligned randomly or if they show a systematic alignment, in order to draw conclusions on the ocean currents at that time. For data processing, we use the 3D modeling software Geomagic Studio and the DTM (Digital Terrain Model) software SCOP++. The entire site has also been systematically documented by a large number of digital photographs. The obtained texture information allows a visual interpretation of the underlying surface. We discuss in how far such a 3D model derived from terrestrial laser scanner data may be useful to support the research work of geoscientists.

Vibrio parahaemolyticus and Vibrio vulnificus Recovered from Oysters during an Oyster Relay Study.

PubMed

Elmahdi, Sara; Parveen, Salina; Ossai, Sylvia; DaSilva, Ligia V; Jahncke, Michael; Bowers, John; Jacobs, John

2018-02-01

Vibrio parahaemolyticus and Vibrio vulnificus are naturally occurring estuarine bacteria and are the leading causes of seafood-associated infections and mortality in the United States. Though multiple-antibiotic-resistant V. parahaemolyticus and V. vulnificus strains have been reported, resistance patterns in vibrios are not as well documented as those of other foodborne bacterial pathogens. Salinity relaying (SR) is a postharvest processing (PHP) treatment to reduce the abundances of these pathogens in shellfish harvested during the warmer months. The purpose of this study was to evaluate the antimicrobial susceptibility (AMS), pathogenicity, and genetic profiles of V. parahaemolyticus and V. vulnificus recovered from oysters during an oyster relay study. Isolates ( V. parahaemolyticus [ n = 296] and V. vulnificus [ n = 94]) were recovered from oysters before and during the 21-day relaying study to detect virulence genes ( tdh and trh ) and genes correlated with virulence ( vcgC ) using multiplex quantitative PCR (qPCR). AMS to 20 different antibiotics was investigated using microbroth dilution, and pulsed-field gel electrophoresis (PFGE) was used to study the genetic profiles of the isolates. Twenty percent of V. vulnificus isolates were vcgC + , while 1 and 2% of V. parahaemolyticus were tdh + and trh + , respectively. More than 77% of the V. vulnificus isolates and 30% of the V. parahaemolyticus isolates were resistant to at least one antimicrobial. Forty-eight percent of V. vulnificus and 8% of V. parahaemolyticus isolates were resistant to two or more antimicrobials. All isolates demonstrated a high genetic diversity, even among those isolated from the same site and having a similar AMS profile. No significant effects of the relaying process on AMS, virulence genes, or PFGE profiles of V. vulnificus and V. parahaemolyticus were observed. IMPORTANCE Analysis of the antibiotic resistance profiles of V. vulnificus and V. parahaemolyticus isolated from oysters

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

Detection and genetic characterization of norovirus in oysters from China and Japan.

PubMed

Phan, Tung Gia; Khamrin, Pattara; Akiyama, Miho; Yagyu, Fumihiro; Okitsu, Shoko; Maneekarn, Niwat; Nishio, Osamu; Ushijima, Hiroshi

2007-01-01

A total of 225 oysters from China and Japan were collected during October 2005 to September 2006 and were then tested for the presence of norovirus by RT-nested PCR. The detection rate of norovirus was different between China and Japan, accounting for 14.6% (19 of 130) and 25.3% (24 of 95), respectively. In China, norovirus in oyster was detected continuously from July to February with the highest prevalence in August, October and November (each of 21%, 4 of 19). On the other hand, norovirus in Japan was found year-round with highest prevalence in March and October (each of 20.8%, 5 of 24). Norovirus strains detected were subjected to further characterization by sequence analysis. It was found that the norovirus strains belonged to only two distinct genotypes, the GII/3 (known as the Mexico virus cluster) and the GII/4 (known as the Lordsdale virus cluster). In China, the norovirus GII/4 was the most predominant, accounting for 78.9% (15 of 19). In contrast, it was interesting that both the norovirus GII/4 and the norovirus GII/3 were co-predominant with a prevalence of 50% (12 of 24) in Japan. Another interesting feature of the study was that the norovirus GII/4 strains in oysters from both countries were grouped into two distinct variant clusters known as the Farmington Hills variant and the Hunter variant. More than 102 copies of norovirus were detected in 41 of 43 oysters. This study provided additional evidence of the presence of norovirus in oysters and is also the first report to demonstrate the existence of norovirus variants in oysters.

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 ...

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

The biology of environmental stress: molecular biomarkers in Sydney rock oysters (Saccostrea glomerata).

PubMed

Raftos, D A; Melwani, A R; Haynes, P A; Muralidharan, S; Birch, G F; Amaral, V; Thompson, E L; Taylor, D A

2016-09-14

This review describes our recent work on environmental stress in Sydney rock oysters, focusing on the identification of molecular biomarkers for ecotoxicological analysis. We begin by describing the environmental pressures facing coastal estuaries in Australia, with particular reference to Sydney Harbour. After providing that context, we summarise our transcriptional and proteomic analyses of Sydney rock oysters responding to chemical contamination and other forms of environmental stress. This work has shown that the intracellular processes of oysters are highly responsive to environmental threats. Our data agree with the broader literature, which suggests that there is a highly conserved intracellular stress response in oysters involving a limited number of biological processes. We conclude that many effective molecular markers for environmental biomonitoring are likely to lie within these biological pathways.

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

2017-06-01

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. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

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

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.

Transcriptome of American Oysters, Crassostrea virginica, in Response to Bacterial Challenge: Insights into Potential Mechanisms of Disease Resistance

PubMed Central

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. PMID:25122115

Stabilization of As-, Pb-, and Cu-contaminated soil using calcined oyster shells and steel slag.

PubMed

Moon, Deok Hyun; Wazne, Mahmoud; Cheong, Kyung Hoon; Chang, Yoon-Young; Baek, Kitae; Ok, Yong Sik; Park, Jeong-Hun

2015-07-01

In this study, As-, Pb-, and Cu-contaminated soil was stabilized using calcined oyster shells (COS) and steel slag (SS). The As-contaminated soil was obtained from a timber mill site where chromate copper arsenate (CCA) was used as a preservative. On the other hand, Pb- and Cu-contaminated soil was obtained from a firing range. These two soils were thoroughly mixed to represent As-, Pb-, and Cu-contaminated soil. Calcined oyster shells were obtained by treating waste oyster shells at a high temperature using the calcination process. The effectiveness of stabilization was evaluated by 1-N HCl extraction for As and 0.1-N HCl extraction for Pb and Cu. The treatment results showed that As, Pb, and Cu leachability were significantly reduced upon the combination treatment of COS and SS. The sole treatment of SS (10 wt%) did not show effective stabilization. However, the combination treatment of COS and SS showed a significant reduction in As, Pb, and Cu leachability. The best stabilization results were obtained from the combination treatment of 15 wt% COS and 10 wt% SS. The SEM-EDX results suggested that the effective stabilization of As was most probably achieved by the formation of Ca-As and Fe-As precipitates. In the case of Pb and Cu, stabilization was most probably associated with the formation of pozzolanic reaction products such as CSHs and CAHs.

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.

Evaluation of impacted Brazilian estuaries using the native oyster Crassostrea rhizophorae: Branchial carbonic anhydrase as a biomarker.

PubMed

Azevedo-Linhares, Maristela; Freire, Carolina A

2015-12-01

In this study, we investigated the use of branchial carbonic anhydrase activity in a sessile filter feeding species, the oyster Crassostrea rhizophorae, as a biomarker. The oysters were collected in three human impacted Brazilian estuaries, following a crescent latitudinal gradient: in Pernambuco state (Itamaracá), in Espírito Santo state (Piraquê), and in Paraná state (Paranaguá), in August/2003 (Winter in the southern hemisphere) and February/2004 (Summer). Three sites were chosen in each estuary for oyster sampling: Reference (R), Contaminated 1 (C1, close to industrial/harbor contamination), and Contaminated 2 (C2, near to sewage discharges). Comparing to values in oysters sampled in reference sites, there was apparent inhibition in carbonic anhydrase activity (CAA) in gills of oysters from C1 of Itamaracá and from C2 of Piraquê, both cases in Summer. On the other hand, increased CAA was noted in C2 oysters of Itamaracá in winter, and of Paranaguá, in both seasons. Branchial CAA in C. rhizophorae was thus very responsive to coastal contamination. Data are consistent with its usefulness as a supporting biomarker for inexpensive and rapid analysis in the assessment of estuaries using a sessile osmoconformer species, but preferably allied to other biomarkers and with knowledge on the suite of contaminants present. Copyright © 2015. Published by Elsevier Inc.

Immune effects of HFO on European sea bass, Dicentrarchus labrax, and Pacific oyster, Crassostrea gigas.

PubMed

Bado-Nilles, Anne; Quentel, Claire; Auffret, Michel; Le Floch, Stéphane; Gagnaire, Béatrice; Renault, Tristan; Thomas-Guyon, Hélène

2009-07-01

The European sea bass, Dicentrarchus labrax, and the Pacific oyster, Crassostrea gigas, were exposed to a soluble fraction of heavy fuel oil for 5 and 9 days, respectively. The organisms were then transferred to non-contaminated seawater for 1 month. The bioaccumulation and elimination of PAHs in contaminated tissues were dissimilar between species. In fish, acenaphthene and naphthalene were detected and naphthalene was still detectable 30 days after the beginning of the recovery period. In oysters, on the other hand, pyrene and phenanthrene were bioaccumulated and 14 days after exposure no more PAHs were detected. Concerning innate immune parameters, the increase of haemolytic activity of the alternative complement pathway in fish and the reduction of phenoloxidase activity in oysters endured, respectively, 1 and 2 weeks in contaminated organisms. This indicates that these two enzymatic cascades could be quite useful for monitoring pollution by oil.

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.

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.

Persistence of Caliciviruses in Artificially Contaminated Oysters during Depuration▿

PubMed Central

Ueki, You; Shoji, Mika; Suto, Atsushi; Tanabe, Toru; Okimura, Yoko; Kikuchi, Yoshihiko; Saito, Noriyuki; Sano, Daisuke; Omura, Tatsuo

2007-01-01

The fate of calicivirus in oysters in a 10-day depuration was assessed. The norovirus gene was persistently detected from artificially contaminated oysters during the depuration, whereas feline calicivirus in oysters was promptly eliminated. The prolonged observation of norovirus in oysters implies the existence of a selective retention mechanism for norovirus within oysters. PMID:17630304

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

Transcriptomic Responses to Salinity Stress in the Pacific Oyster Crassostrea gigas

PubMed Central

Zhao, Xuelin; Yu, Hong; Kong, Lingfeng; Li, Qi

2012-01-01

Background Low salinity is one of the main factors limiting the distribution and survival of marine species. As a euryhaline species, the Pacific oyster Crassostrea gigas is considered to be tolerant to relative low salinity. The genes that regulate C. gigas responses to osmotic stress were monitored using the next-generation sequencing of whole transcriptome with samples taken from gills. By RNAseq technology, transcript catalogs of up- and down-regulated genes were generated from the oysters exposed to low and optimal salinity seawater. Methodology/Principal Findings Through Illumina sequencing, we reported 1665 up-regulated transcripts and 1815 down-regulated transcripts. A total of 45771 protein-coding contigs were identified from two groups based on sequence similarities with known proteins. As determined by GO annotation and KEGG pathway mapping, functional annotation of the genes recovered diverse biological functions and processes. The genes that changed expression significantly were highly represented in cellular process and regulation of biological process, intracellular and cell, binding and protein binding according to GO annotation. The results highlighted genes related to osmoregulation, signaling and interactions of osmotic stress response, anti-apoptotic reactions as well as immune response, cell adhesion and communication, cytoskeleton and cell cycle. Conclusions/Significance Through more than 1.5 million sequence reads and the expression data of the two libraries, the study provided some useful insights into signal transduction pathways in oysters and offered a number of candidate genes as potential markers of tolerance to hypoosmotic stress for oysters. In addition, the characterization of C. gigas transcriptome will not only provide a better understanding of the molecular mechanisms about the response to osmotic stress of the oysters, but also facilitate research into biological processes to find underlying physiological adaptations to

The risk of Vibrio parahaemolyticus infections associated with consumption of raw oysters as affected by processing and distribution conditions in Taiwan

USDA-ARS?s Scientific Manuscript database

The steadily increased consumption of raw oysters in Taiwan warrants an assessment of the risk (probability of illness) of raw oyster consumption attributed by Vibrio parahaemolyticus. The aim of this study was to estimate the risk of V. parahaemolyticus infection associated with raw oyster consumpt...

High hydrostatic pressure processing of murine norovirus 1-contaminated oysters inhibits oral infection in STAT-1 -/- deficient female mice

USDA-ARS?s Scientific Manuscript database

We have previously demonstrated that high pressure processing (HPP) is effective in preventing in vitro replication of murine norovirus strain 1 (MNV-1), a human norovirus surrogate, in a monocyte cell line following extraction from MNV-1-contaminated oysters. In the present study, the efficacy of ...

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

DTIC Science & Technology

2014-11-01

White, M., Powell. E., and Ray, S. (1988). “Effects of parasitism by the pyramidellid gastropod Boonea impressa on the net productivity of oysters...Effects of parasitism by the pyramidellid gastropod Boonea impressa on the net productivity of oysters (Crassostrea viginica),” Estuarine Coastal...Wisconsin Fish Model (Hanson et al. 1997) and was adapted for a model of Atlantic menhaden in Chesapeake Bay (Dalyander and Cerco 2010). Subsequent

Production of biodiesel from Chlorella sp. enriched with oyster shell extracts.

PubMed

Choi, Cheol Soon; Choi, Woon Yong; Kang, Do Hyung; Lee, Hyeon Yong

2014-01-01

This study investigated the cultivation of the marine microalga Chlorella sp. without supplying an inorganic carbon source, but instead with enriching the media with extracts of oyster shells pretreated by a high-pressure homogenization process. The pretreated oyster shells were extracted by a weak acid, acetic acid, that typically has harmful effects on cell growth and also poses environmental issues. The concentration of the residual dissolved carbon dioxide in the medium was sufficient to maintain cell growth at 32 ppm and pH 6.5 by only adding 5% (v/v) of oyster shell extracts. Under this condition, the maximum cell density observed was 2.74 g dry wt./L after 27 days of cultivation. The total lipid content was also measured as 18.1 (%, w/w), and this value was lower than the 23.6 (%, w/w) observed under nitrogen deficient conditions or autotrophic conditions. The fatty acid compositions of the lipids were also measured as 10.9% of C16:1 and 16.4% of C18:1 for the major fatty acids, which indicates that the biodiesel from this culture process should be a suitable biofuel. These results suggest that oyster shells, environmental waste from the food industry, can be used as a nutrient and carbon source with seawater, and this reused material should be important for easily scaling up the process for an outdoor culture system.

21 CFR 161.130 - Oysters.

Code of Federal Regulations, 2010 CFR

2010-04-01

... water. Before packing into the containers for shipment or other delivery for consumption the oysters are... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION FISH AND SHELLFISH Requirements for Specific Standardized Fish and Shellfish § 161.130 Oysters. (a...

Spatial patterns in the condition index of the wild Pacific oyster Crassostrea gigas in a macrotidal coastal ecosystem: Influence of tidal processes and beyond

NASA Astrophysics Data System (ADS)

Gasmi, Sonia; Bernard, Ismaël; Pouvreau, Stéphane; Maurer, Danièle; Schaal, Gauthier; Ganthy, Florian; Cominassi, Louise; Allain, Gwenhael; Sautour, Benoit; David, Valérie

2017-01-01

In macrotidal coastal ecosystems, spatial heterogeneity of the water column properties is induced by both oceanic and continental influences. Hydrodynamic processes generate a land-sea gradient of environmental conditions, affecting the biological performances of sedentary organisms. The aim of the present study is to establish an extensive spatial assessment in the reproductive investment of the wild Pacific oyster Crassostrea gigas in Arcachon Bay. This is done by looking for a relationship between the Lawrence and Scott condition index (LSCI) and two tidal processes: the immersion level (IL) and the local oceanic flushing time (LoFt). The LSCI of C. gigas was assessed, just before gamete release, at 68 sampling stations in Arcachon Bay. Oyster performance was overall low and spatially variable. Significant differences in the LSCI were detected between the outer and inner bay. Oyster reefs located toward the mouth of the bay exhibited high LSCI (between 9 and 11), while oyster reefs located in inner bay, especially in south-eastern part around the Eyre River, had low LSCI (below 6). Linear modelling allowed to highlight significant effects of both tidal processes IL and LoFt on the obtained LSCI gradient. IL, LoFt explained 33% of the spatial variability observed on LSCI (IL = 3%; LoFt = 17%; LoFt + IL: 13%), 6% were attributed to the intra-station variation (ISv). Thus, high IL and rapid LoFt favor a better development of somatic-gonadal volume, probably because of longer feeding time and higher supply of food from the ocean by tide flows. Disentangling the effects of IL and LoFt on LSCI allowed to describe the spatial pattern in 61% of variability not explained by both tidal factors. A residual gradient directed southeast-northwest highlighted that others factors, independent from IL and LoFt seems to hamper inner bay oyster reproductive performance. Consequently, investigating on the ecological functioning (Eyre influences), trophic potential and anthropogenic

Contrasting impacts of ocean acidification and warming on the molecular responses of CO2-resilient oysters.

PubMed

Goncalves, Priscila; Thompson, Emma L; Raftos, David A

2017-06-02

This study characterises the molecular processes altered by both elevated CO 2 and increasing temperature in oysters. Differences in resilience of marine organisms against the environmental stressors associated with climate change will have significant implications for the sustainability of coastal ecosystems worldwide. Some evidence suggests that climate change resilience can differ between populations within a species. B2 oysters represent a unique genetic resource because of their capacity to better withstand the impacts of elevated CO 2 at the physiological level, compared to non-selected oysters from the same species (Saccostrea glomerata). Here, we used proteomic and transcriptomic analysis of gill tissue to evaluate whether the differential response of B2 oysters to elevated CO 2 also extends to increased temperature. Substantial and distinctive effects on protein concentrations and gene expression were evident among B2 oysters responding to elevated CO 2 or elevated temperature. The combination of both stressors also altered oyster gill proteomes and gene expression. However, the impacts of elevated CO 2 and temperature were not additive or synergistic, and may be antagonistic. The data suggest that the simultaneous exposure of CO 2 -resilient oysters to near-future projected ocean pH and temperature results in complex changes in molecular processes in order to prevent stress-induced cellular damage. The differential response of B2 oysters to the combined stressors also indicates that the addition of thermal stress may impair the resilience of these oysters to decreased pH. Overall, this study reveals the intracellular mechanisms that might enable marine calcifiers to endure the emergent, adverse seawater conditions resulting from climate change.

The biofilteration ability of oysters (Crassostrea gigas) to reduce Aeromonas salmonicida in salmon culture.

PubMed

Ma, Xiaona; Li, Xian; Sun, Guoxiang; Sharawy, Zaki Zaki; Qiu, Tianlong; Du, Yishuai; Liu, Ying

2017-07-01

Pathogen contamination in the environment is inevitable with the rapid development of intensive aquaculture. Therefore, alternative ecofriendly biological strategies to control pathogenic bacteria are required. However, our aim was to investigate the ability of oysters (Crassostrea gigas) to filter the important opportunistic pathogen, Aeromonas salmonicida (strain C4), using a green fluorescent protein tag (GFP) in the Atlantic salmon (Salmo salar) farming wastewater. Hence, A. salmonicida removal efficiency and ingestion rate were detected in two different oyster stages (larvae and adults). To evaluate the practical performance of oysters as A. salmonicida biofilter, adult oysters were applied to an integrated constructed wetlands system (ICWS) and their long-term C4-GFP removal efficiency was recorded for 60 days. Overall, our results clearly indicated that oysters had substantial A. salmonicida removal ability via their ingestion process when observed under a fluorescent microscope. Approximately 88-95% of C4-GFP was removed by oyster larvae at an ingestion rate of 6.4 × 10 3 -6.2 × 10 5  CFU/h·ind, while 79-92% of C4-GFP was removed by adult oysters at an ingestion rate of 2.1 × 10 4 -3.1 × 10 6  CFU/h·ind. Furthermore, 57.9 ± 17.2% of C4-GFP removal efficiency was achieved when oysters were applied to ICWS. We, therefore, concluded that using oysters as a biofilter represents an effective alternative for removing A. salmonicida from aquaculture wastewater. However, the fate of oysters after ingesting the pathogenic bacteria, acting as a potential reservoir or vector for pathogens, is still debatable. This research provides the basis for the application of oysters as a biofilter to remove pathogens from aquaculture wastewater in industrialized production.

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...

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.

Estimating the impact of oyster restoration scenarios on transient fish production

USGS Publications Warehouse

McCoy, Elizabeth; Borrett, Stuart R.; LaPeyre, Megan K.; Peterson, Bradley J.

2017-01-01

Oyster reef restoration projects are increasing in number both to enhance oyster density and to retain valuable ecosystem services provided by oyster reefs. Although some oyster restoration projects have demonstrated success by increasing density and biomass of transient fish, it still remains a challenge to quantify the effects of oyster restoration on transient fish communities. We developed a bioenergetics model to assess the impact of selected oyster reef restoration scenarios on associated transient fish species. We used the model to analyze the impact of changes in (1) oyster population carrying capacity; (2) oyster population growth rate; and (3) diet preference of transient fish on oyster reef development and associated transient fish species. Our model results indicate that resident fish biomass is directly affected by oyster restoration and oyster biomass, and oyster restoration can have cascading impacts on transient fish biomass. Furthermore, the results highlight the importance of a favorable oyster population growth rate during early restoration years, as it can lead to rapid increases in mean oyster biomass and biomass of transient fish species. The model also revealed that a transient fish's diet solely dependent on oyster reef-derived prey could limit the biomass of transient fish species, emphasizing the importance of habitat connectivity in estuarine areas to enhance transient fish species biomass. Simple bioenergetics models can be developed to understand the dynamics of a system and make qualitative predictions of management and restoration scenarios.

Human enteroviruses in oysters and their overlying waters.

PubMed Central

Goyal, S M; Gerba, C P; Melnick, J L

1979-01-01

The presence of enteroviruses in oysters and oyster-harvesting waters of the Texas Gulf coast was monitored over a period of 10 months. Viruses were detected in water and oyster samples obtained from areas both open and closed to shellfish harvesting. Viruses were detected periodically in waters that met current bacteriological standards for shellfish harvesting. No significant statistical relationship was demonstrated between virus concentration in oysters and the bacteriological and physiochemical quality of water and shellfish. Viruses in water were, however, moderately correlated with total coliforms in water and oysters and with fecal coliforms in oysters. Total coliforms in water were realted to total coliforms in sediment were related only to total coliforms in sediment. Among the physiochemical characteristics of water, turbidity was related statistically to the organic matter content of water and to fecal coliforms in water. There was a marked effect of rainfall on the bacteriological quality of water. Of a total of 44 water samples, 26 yielded virus in concentrations from 4 to 167 plaque-forming units per 100-gallon (ca. 378.5-liter) sample. Of a total of 40 pools of 10 to 12 oysters each, virus was found in 14 pools at a concentration of 6 to 224 plaque-forming units per 100 g of oyster meat. On five occasions, virus was found in water samples when no virus could be detected in oysters harvested from the same sites. This study indicates that current bacteriological standards for determining the safety of shellfish and shellfish-growing waters do no reflect the occurrence of enteroviruses. PMID:222210

Human enteroviruses in oysters and their overlying waters.

PubMed

Goyal, S M; Gerba, C P; Melnick, J L

1979-03-01

The presence of enteroviruses in oysters and oyster-harvesting waters of the Texas Gulf coast was monitored over a period of 10 months. Viruses were detected in water and oyster samples obtained from areas both open and closed to shellfish harvesting. Viruses were detected periodically in waters that met current bacteriological standards for shellfish harvesting. No significant statistical relationship was demonstrated between virus concentration in oysters and the bacteriological and physiochemical quality of water and shellfish. Viruses in water were, however, moderately correlated with total coliforms in water and oysters and with fecal coliforms in oysters. Total coliforms in water were realted to total coliforms in sediment were related only to total coliforms in sediment. Among the physiochemical characteristics of water, turbidity was related statistically to the organic matter content of water and to fecal coliforms in water. There was a marked effect of rainfall on the bacteriological quality of water. Of a total of 44 water samples, 26 yielded virus in concentrations from 4 to 167 plaque-forming units per 100-gallon (ca. 378.5-liter) sample. Of a total of 40 pools of 10 to 12 oysters each, virus was found in 14 pools at a concentration of 6 to 224 plaque-forming units per 100 g of oyster meat. On five occasions, virus was found in water samples when no virus could be detected in oysters harvested from the same sites. This study indicates that current bacteriological standards for determining the safety of shellfish and shellfish-growing waters do no reflect the occurrence of enteroviruses.

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)

New Hampshire recreational oyster harvesters: profile, perceptions, and attitudes

Treesearch

Alberto B. Manalo; Bruce E. Lindsay; George E. Frick

1992-01-01

A survey of holders of a 1989 New Hampshire oyster-harvesting license revealed that recreational oyster harvesting is pursued mostly by older men. The 1988 closing of some parts of Great Bay to oyster harvesting resulted in license holders' taking one fewer trip and taking about six minutes longer to harvest one bushel of oysters in 1989. The average annual...

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

Production of Biodiesel from Chlorella sp. Enriched with Oyster Shell Extracts

PubMed Central

Choi, Woon Yong; Kang, Do Hyung; Lee, Hyeon Yong

2014-01-01

This study investigated the cultivation of the marine microalga Chlorella sp. without supplying an inorganic carbon source, but instead with enriching the media with extracts of oyster shells pretreated by a high-pressure homogenization process. The pretreated oyster shells were extracted by a weak acid, acetic acid, that typically has harmful effects on cell growth and also poses environmental issues. The concentration of the residual dissolved carbon dioxide in the medium was sufficient to maintain cell growth at 32 ppm and pH 6.5 by only adding 5% (v/v) of oyster shell extracts. Under this condition, the maximum cell density observed was 2.74 g dry wt./L after 27 days of cultivation. The total lipid content was also measured as 18.1 (%, w/w), and this value was lower than the 23.6 (%, w/w) observed under nitrogen deficient conditions or autotrophic conditions. The fatty acid compositions of the lipids were also measured as 10.9% of C16:1 and 16.4% of C18:1 for the major fatty acids, which indicates that the biodiesel from this culture process should be a suitable biofuel. These results suggest that oyster shells, environmental waste from the food industry, can be used as a nutrient and carbon source with seawater, and this reused material should be important for easily scaling up the process for an outdoor culture system. PMID:24696841

Dynamics of DNA methylomes underlie oyster development.

PubMed

Riviere, Guillaume; He, Yan; Tecchio, Samuele; Crowell, Elizabeth; Gras, Michaël; Sourdaine, Pascal; Guo, Ximing; Favrel, Pascal

2017-06-01

DNA methylation is a critical epigenetic regulator of development in mammals and social insects, but its significance in development outside these groups is not understood. Here we investigated the genome-wide dynamics of DNA methylation in a mollusc model, the oyster Crassostrea gigas, from the egg to the completion of organogenesis. Large-scale methylation maps reveal that the oyster genome displays a succession of methylated and non methylated regions, which persist throughout development. Differentially methylated regions (DMRs) are strongly regulated during cleavage and metamorphosis. The distribution and levels of methylated DNA within genomic features (exons, introns, promoters, repeats and transposons) show different developmental lansdscapes marked by a strong increase in the methylation of exons against introns after metamorphosis. Kinetics of methylation in gene-bodies correlate to their transcription regulation and to distinct functional gene clusters, and DMRs at cleavage and metamorphosis bear the genes functionally related to these steps, respectively. This study shows that DNA methylome dynamics underlie development through transcription regulation in the oyster, a lophotrochozoan species. To our knowledge, this is the first demonstration of such epigenetic regulation outside vertebrates and ecdysozoan models, bringing new insights into the evolution and the epigenetic regulation of developmental processes.

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

Pyrosequencing Analysis of Norovirus Genogroup II Distribution in Sewage and Oysters: First Detection of GII.17 Kawasaki 2014 in Oysters.

PubMed

Pu, Jian; Kazama, Shinobu; Miura, Takayuki; Azraini, Nabila Dhyan; Konta, Yoshimitsu; Ito, Hiroaki; Ueki, You; Cahyaningrum, Ermaya Eka; Omura, Tatsuo; Watanabe, Toru

2016-12-01

Norovirus GII.3, GII.4, and GII.17 were detected using pyrosequencing in sewage and oysters in January and February 2015, in Japan. The strains in sewage and oyster samples were genetically identical or similar, predominant strains belonging to GII.17 Kawasaki 2014 lineage. This is the first report of GII.17 Kawasaki 2014 in oysters.

Photosynthetic epibionts and endobionts of Pacific oyster shells from oyster reefs in rocky versus mudflat shores.

PubMed

Barillé, Laurent; Le Bris, Anthony; Méléder, Vona; Launeau, Patrick; Robin, Marc; Louvrou, Ioanna; Ribeiro, Lourenço

2017-01-01

The Pacific oyster, Crassostrea gigas (Thunberg), is the main bivalve species cultivated in the world. With global warming enabling its reproduction and larval survival at higher latitudes, this species is now recognized as invasive and creates wild oyster reefs globally. In this study, the spatial distribution of photosynthetic assemblages colonizing the shells of wild C. gigas was investigated on both a large scale (two contrasting types of reefs found in mudflats and rocky areas) and a small scale (within individual shells) using a hyperspectral imager. The microspatial distribution of all phototrophs was obtained by mapping the Normalized Difference Vegetation Index (NDVI). Second derivative (δδ) analyses of hyperspectral images at 462, 524, 571 and 647 nm were subsequently applied to map diatoms, cyanobacteria, rhodophytes and chlorophytes, respectively. A concomitant pigment analysis was carried out by high performance liquid chromatography and completed by taxonomic observations. This study showed that there was high microalgal diversity associated with wild oyster shells and that there were differences in the structure of the phototropic assemblages depending on the type of reef. Namely, vertically-growing oysters in mudflat areas had a higher biomass of epizoic diatoms (hyperspectral proxy at δδ462 nm) and were mainly colonized by species of the genera Navicula, Nitzschia and Hippodonta, which are epipelic or motile epipsammic. The assemblages on the horizontal oysters contained more tychoplanktonic diatoms (e.g. Thalassiosira pseudonana, T. proschkinae and Plagiogrammopsis vanheurckii). Three species of boring cyanobacteria were observed for both types of reef: Mastigocoleus testarum, Leptolyngbya terrebrans, and Hyella caespistosa, but the second derivative analysis at 524 nm showed a significantly higher biomass for the horizontally-growing oysters. There was no biomass difference for the boring chlorophyte assemblages (δδ647 nm), with two species

Photosynthetic epibionts and endobionts of Pacific oyster shells from oyster reefs in rocky versus mudflat shores

PubMed Central

Le Bris, Anthony; Méléder, Vona; Launeau, Patrick; Robin, Marc; Louvrou, Ioanna; Ribeiro, Lourenço

2017-01-01

The Pacific oyster, Crassostrea gigas (Thunberg), is the main bivalve species cultivated in the world. With global warming enabling its reproduction and larval survival at higher latitudes, this species is now recognized as invasive and creates wild oyster reefs globally. In this study, the spatial distribution of photosynthetic assemblages colonizing the shells of wild C. gigas was investigated on both a large scale (two contrasting types of reefs found in mudflats and rocky areas) and a small scale (within individual shells) using a hyperspectral imager. The microspatial distribution of all phototrophs was obtained by mapping the Normalized Difference Vegetation Index (NDVI). Second derivative (δδ) analyses of hyperspectral images at 462, 524, 571 and 647 nm were subsequently applied to map diatoms, cyanobacteria, rhodophytes and chlorophytes, respectively. A concomitant pigment analysis was carried out by high performance liquid chromatography and completed by taxonomic observations. This study showed that there was high microalgal diversity associated with wild oyster shells and that there were differences in the structure of the phototropic assemblages depending on the type of reef. Namely, vertically-growing oysters in mudflat areas had a higher biomass of epizoic diatoms (hyperspectral proxy at δδ462 nm) and were mainly colonized by species of the genera Navicula, Nitzschia and Hippodonta, which are epipelic or motile epipsammic. The assemblages on the horizontal oysters contained more tychoplanktonic diatoms (e.g. Thalassiosira pseudonana, T. proschkinae and Plagiogrammopsis vanheurckii). Three species of boring cyanobacteria were observed for both types of reef: Mastigocoleus testarum, Leptolyngbya terrebrans, and Hyella caespistosa, but the second derivative analysis at 524 nm showed a significantly higher biomass for the horizontally-growing oysters. There was no biomass difference for the boring chlorophyte assemblages (δδ647 nm), with two species

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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…

Molecular analysis of an oyster-related norovirus outbreak.

PubMed

Nenonen, Nancy P; Hannoun, Charles; Olsson, Margareta B; Bergström, Tomas

2009-06-01

Contaminated raw oysters were implicated in a severe outbreak of norovirus (NoV) gastroenteritis affecting 30 restaurant guests. To define the outbreak source by using molecular methods to characterize NoV strains detected in patient and oyster samples. Molecular epidemiological studies based on nucleotide sequencing and phylogenetic analyses of patient and oyster NoV strains, and comparison to background dataset. NoV genotype (G) I.1 was detected in the one patient stool analyzed by in-house TaqMan real time RT-PCR and classical nested RT-PCR targeting NoV RNA-dependent polymerase (RdRp, 285 nt), and by nested RT-PCR targeting RdRp-capsid-poly(A)-3' (3085 nt). Patient strain showed >or=99% similarity (285 nt) with three NoV strains detected in two of five oysters examined by classical nested RT-PCR (RdRp). A third oyster tested positive for NoV GII.3. Phylogenetic analysis showed clustering of patient and oyster strains related to this outbreak with GI.1 strains from previous local outbreaks, and mussel studies. Sequence data revealed >or=99% similarity (285 nt) between NoV GI.1 strains detected in patient stool and suspect oysters, linking the contaminated oysters to the outbreak. Identification of human NoV GI and GII strains in oysters indicated contamination of human fecal origin, presumably from inappropriate storage in the harbor. Comparative long-fragment analysis of the patient strain revealed 99% similarity (3085 nt) with NoV GI.1 strains detected in previous outbreaks and environmental mussel studies from West Sweden, 87% with M87661 (Norwalk68) and 96% with L23828 (SRSV-KY-89/89/J). These results indicated considerable genomic stability of NoV GI.1 strains over time.

Microcontroller based automatic temperature control for oyster mushroom plants

NASA Astrophysics Data System (ADS)

Sihombing, P.; Astuti, T. P.; Herriyance; Sitompul, D.

2018-03-01

In the cultivation of Oyster Mushrooms need special treatment because oyster mushrooms are susceptible to disease. Mushroom growth will be inhibited if the temperature and humidity are not well controlled because temperature and inertia can affect mold growth. Oyster mushroom growth usually will be optimal at temperatures around 22-28°C and humidity around 70-90%. This problem is often encountered in the cultivation of oyster mushrooms. Therefore it is very important to control the temperature and humidity of the room of oyster mushroom cultivation. In this paper, we developed an automatic temperature monitoring tool in the cultivation of oyster mushroom-based Arduino Uno microcontroller. We have designed a tool that will control the temperature and humidity automatically by Android Smartphone. If the temperature increased more than 28°C in the room of mushroom plants, then this tool will turn on the pump automatically to run water in order to lower the room temperature. And if the room temperature of mushroom plants below of 22°C, then the light will be turned on in order to heat the room. Thus the temperature in the room oyster mushrooms will remain stable so that the growth of oyster mushrooms can grow with good quality.

Assessment of pollution of the Boca de Camichin Estuary in Nayarit (Mexico) and its influence on oxidative stress in Crassostrea corteziensis oysters.

PubMed

Toledo-Ibarra, G A; Díaz Resendiz, K J G; Ventura-Ramón, G H; Romero-Bañuelos, C A; Medina-Díaz, I M; Rojas-García, A E; Vega-López, A; Girón-Pérez, M I

2016-10-01

Boca de Camichin Estuary is one of the main producers of Crassostrea corteziensis oysters in Mexico, but the presence of pollutants can affect oyster production. Molluscs produce reactive oxygen species (ROS) in response to changes in the environment and pollution. These ROS induce oxidative damage in biomolecules. The main objective of this study was to evaluate pollution in the estuary and the subsequent oxidative stress in C. corteziensis oysters during the 2010 production cycle. For this aim, we performed monthly samplings in the oyster farms from January to May. We took water samples to quantify polycyclic aromatic hydrocarbon (PAH) and metal content; also, we evaluated oxidative damage (lipoperoxidation, lipidic hydroperoxides, protein oxidation) and enzyme activity (CAT, SOD, GPx, GST and AChE) in oyster gills. The results show the presence of Cu, Fe, Mn, naphthalene, benz[a]anthracene, pyrene, benz[a]pyrene and benzo[k]fluoranthene. On the other hand, AChE activity was not inhibited, which suggests that organophosphorus pollutants or carbamates were absent. Regarding oxidative stress, oysters from the estuary had oxidative damage in lipids, not proteins, and altered antioxidant enzyme activity, when compared to control organisms. Interestingly, we did not observe any correlation between the pollutants and the oxidative stress parameters evaluated in this study. Thus, we cannot rule out that a synergistic effect between the environmental variables and the pollutants is causing the oxidative stress in these oysters. Copyright © 2016 Elsevier Inc. All rights reserved.

Thiabendazole uptake in shimeji, king oyster, and oyster mushrooms and its persistence in sterile and nonsterile substrates.

PubMed

Zhang, Zhiyong; Jiang, Wayne; Jian, Qiu; Song, Wencheng; Zheng, Zuntao; Ke, Changjie; Liu, Xianjin

2014-02-12

Thiabendazole in the substrates incurred from spraying and premixing was translocated to the pileus, stipe, and volva of selected mushrooms. The spraying on the substrates resulted in higher residues of thiabendazole in all three mushrooms than the premixing treatment. For premixing, in the five substrates, half-lives of thiabendazole were found to be 13.6 days for shimeji, 10.0 days for king oyster, 13.7 days for oyster, 19.1 days for sterilized substrate, and 8.4 days for nonsterilized substrate, respectively. For spraying, the longest and shortest half-lives were found to be 19.5 and 8.1 days for the nonsterilized and sterilized substrates, respectively. The residues of thiabendazole in three edible fungi were increased with the incubation days from 3 to 5 to 7. The residues of thiabendazole in king oyster were the highest among the three fungi while those in shimeji and oyster showed similar patterns.

Preliminary Evaluation of Microbial Communities Isolated from the Calcifying Fluid of Oysters

NASA Astrophysics Data System (ADS)

Banker, R.

2016-02-01

The process of biomineralization is defined as the selective uptake of elements that are incorporated into a defined mineral structure under strict biological control. For bivalve molluscs, such as clams, oysters, and mussels, the mantle is the primary organ in control of shell deposition. Alternatively, remote calcification takes place when carbonate-precipitating microbes (e.g. sulfate reducers) colonize a shell-secreting organism and enhance the ability of the host to build shell material. The oyster syndrome is a term that describes bivalves that possess an unusual shell morphology characterized by exceptionally thick valves containing numerous chambers filled with chalky calcite. Although remote calcification via microbial metabolism has been proposed as a mechanism of chalky deposit formation in oysters, this hypothesis has not yet been rigorously investigated. Here I present data on the microbial communities found in the calcifying fluid of two oyster species; Crassostrea gigas and Ostrea lurida are examples of oysters that do and do not exhibit the oyster syndrome, respectively. Comparison of the microbiomes of these two morphological end members may provide insight into the role of microbes in the formation of chalky deposits. Results indicate that the microbial community in the surrounding water is the dominant source for bacterial taxa found in the calcifying fluid of both oyster species. Also, it appears as though C. gigas maintains a microbial community that is more similar to its ambient environment than O. lurida. These results demonstrate that the ambient aquatic environment has a guiding influence on the microbiome found in the calcifying fluid of bivalve molluscs. However, the magnitude of this effect varies among organisms, even those that are closely related.

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.

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

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.

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. Copyright © 2012 Elsevier B.V. All rights reserved.

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.

Hand controller commonality evaluation process

NASA Technical Reports Server (NTRS)

Stuart, Mark A.; Bierschwale, John M.; Wilmington, Robert P.; Adam, Susan C.; Diaz, Manuel F.; Jensen, Dean G.

1990-01-01

A hand controller evaluation process has been developed to determine the appropriate hand controller configurations for supporting remotely controlled devices. These devices include remote manipulator systems (RMS), dexterous robots, and remotely-piloted free flyers. Standard interfaces were developed to evaluate six different hand controllers in three test facilities including dynamic computer simulations, kinematic computer simulations, and physical simulations. The hand controllers under consideration were six degree-of-freedom (DOF) position and rate minimaster and joystick controllers, and three-DOF rate controllers. Task performance data, subjective comments, and anthropometric data obtained during tests were used for controller configuration recommendations to the SSF Program.

Dynamics of DNA methylomes underlie oyster development

PubMed Central

Sourdaine, Pascal; Guo, Ximing; Favrel, Pascal

2017-01-01

DNA methylation is a critical epigenetic regulator of development in mammals and social insects, but its significance in development outside these groups is not understood. Here we investigated the genome-wide dynamics of DNA methylation in a mollusc model, the oyster Crassostrea gigas, from the egg to the completion of organogenesis. Large-scale methylation maps reveal that the oyster genome displays a succession of methylated and non methylated regions, which persist throughout development. Differentially methylated regions (DMRs) are strongly regulated during cleavage and metamorphosis. The distribution and levels of methylated DNA within genomic features (exons, introns, promoters, repeats and transposons) show different developmental lansdscapes marked by a strong increase in the methylation of exons against introns after metamorphosis. Kinetics of methylation in gene-bodies correlate to their transcription regulation and to distinct functional gene clusters, and DMRs at cleavage and metamorphosis bear the genes functionally related to these steps, respectively. This study shows that DNA methylome dynamics underlie development through transcription regulation in the oyster, a lophotrochozoan species. To our knowledge, this is the first demonstration of such epigenetic regulation outside vertebrates and ecdysozoan models, bringing new insights into the evolution and the epigenetic regulation of developmental processes. PMID:28594821

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.

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.

Suspension of oysters reduces the populations of Vibrio parahaemolyticus and Vibrio vulnificus.

PubMed

Cole, K M; Supan, J; Ramirez, A; Johnson, C N

2015-09-01

Vibrio parahaemolyticus (Vp) and Vibrio vulnificus (Vv) are associated with the consumption of raw oysters and cause illnesses ranging from simple gastroenteritis to life-threatening septicaemia. These halophilic bacteria are frequently found in marine and estuarine systems, accumulating within the tissues of a number of aquatic organisms and passing on to humans after consumption, through contaminated water, or via open wounds. As benthic organisms capable of filtering 40 gallons of water per hour, sediment is an important source of potentially pathogenic vibrios in oysters destined for raw consumption. This research used off-bottom oyster culture to reduce vibrio concentrations in oysters. Colony hybridization was used to enumerate Vp and Vv in bottom and suspended oysters. Vv and Vp concentrations were generally lower in oysters suspended off-bottom, and suspension decreased vibrio loads in oysters by an average of 13%. Suspension of oysters reduced vibrio concentrations. This study found that oyster suspension significantly reduced some populations of potentially pathogenic vibrios. These results indicate that oyster suspension could be a viable approach for preharvest treatment to reduce illness in consumers of raw oysters. © 2015 The Society for Applied Microbiology.

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 Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... and conform to the definition and standard of identity prescribed for oysters in § 161.130. ...

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 Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... and conform to the definition and standard of identity prescribed for oysters in § 161.130. ...

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

PubMed Central

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

2015-01-01

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. PMID:26293805

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

Evaluation of the proximate quality of the combination of Tuna (Thunnus albacares) and white oyster mushroom (Pleurotus ostreatus) nuggets

NASA Astrophysics Data System (ADS)

Yufidasari, H. S.; Prihanto, A. A.; Nurdiani, R.; Jaziri, A. A.

2018-04-01

Nugget is a processed meat product which has great market demand but need variations to increase its nutritional content. Tuna is rich in omega-3 protein, vitamins, and minerals. White oyster mushrooms have high nutritional content which are about 23-33% protein, 36-68 % carbohydrates and 12-22 % amino acids. The purpose of this research is to evaluate the chemical quality of Tuna nugget (Thunnus albacores) with combination of white oyster mushroom (Pleurotus ostreatus). Complete Randomized Design (RAL) with parameters of Tuna and white oyster mushroom formulation, TJ1 (70 % Tuna: 30 % white oyster mushroom), TJ2 (50 % Tuna: 50 % white oyster mushroom), TJ3 (30 % Tuna: 70 % white oyster mushroom), and Control or K Treatment (100 % Tuna) is used. Results of Tuna nuggets with white oyster mushroom combination showed the highest value of water content in TJ3 50.14 %, protein K 19.6 %, fat TJ3 22.98 %, ash K 3.99 % and 2.47 % crude fiber. From these results, there is a need for further research on fat, ash and coarse fiber content that is used in the manufacture of fish nuggets combined with oyster mushrooms because it failed to meet Indonesian National Standard (SNI).

Spatial and Temporal Dynamics of Mass Mortalities in Oysters Is Influenced by Energetic Reserves and Food Quality

PubMed Central

Pernet, Fabrice; Lagarde, Franck; Jeannée, Nicolas; Daigle, Gaetan; Barret, Jean; Le Gall, Patrik; Quere, Claudie; D’orbcastel, Emmanuelle Roque

2014-01-01

Although spatial studies of diseases on land have a long history, far fewer have been made on aquatic diseases. Here, we present the first large-scale, high-resolution spatial and temporal representation of a mass mortality phenomenon cause by the Ostreid herpesvirus (OsHV-1) that has affected oysters (Crassostrea gigas) every year since 2008, in relation to their energetic reserves and the quality of their food. Disease mortality was investigated in healthy oysters deployed at 106 locations in the Thau Mediterranean lagoon before the start of the epizootic in spring 2011. We found that disease mortality of oysters showed strong spatial dependence clearly reflecting the epizootic process of local transmission. Disease initiated inside oyster farms spread rapidly beyond these areas. Local differences in energetic condition of oysters, partly driven by variation in food quality, played a significant role in the spatial and temporal dynamics of disease mortality. In particular, the relative contribution of diatoms to the diet of oysters was positively correlated with their energetic reserves, which in turn decreased the risk of disease mortality. PMID:24551106

Spatial and temporal dynamics of mass mortalities in oysters is influenced by energetic reserves and food quality.

PubMed

Pernet, Fabrice; Lagarde, Franck; Jeannée, Nicolas; Daigle, Gaetan; Barret, Jean; Le Gall, Patrik; Quere, Claudie; D'orbcastel, Emmanuelle Roque

2014-01-01

Although spatial studies of diseases on land have a long history, far fewer have been made on aquatic diseases. Here, we present the first large-scale, high-resolution spatial and temporal representation of a mass mortality phenomenon cause by the Ostreid herpesvirus (OsHV-1) that has affected oysters (Crassostrea gigas) every year since 2008, in relation to their energetic reserves and the quality of their food. Disease mortality was investigated in healthy oysters deployed at 106 locations in the Thau Mediterranean lagoon before the start of the epizootic in spring 2011. We found that disease mortality of oysters showed strong spatial dependence clearly reflecting the epizootic process of local transmission. Disease initiated inside oyster farms spread rapidly beyond these areas. Local differences in energetic condition of oysters, partly driven by variation in food quality, played a significant role in the spatial and temporal dynamics of disease mortality. In particular, the relative contribution of diatoms to the diet of oysters was positively correlated with their energetic reserves, which in turn decreased the risk of disease mortality.

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.

Satellite remote sensing reveals a positive impact of living oyster reefs on microalgal biofilm development

NASA Astrophysics Data System (ADS)

Echappé, Caroline; Gernez, Pierre; Méléder, Vona; Jesus, Bruno; Cognie, Bruno; Decottignies, Priscilla; Sabbe, Koen; Barillé, Laurent

2018-02-01

Satellite remote sensing (RS) is routinely used for the large-scale monitoring of microphytobenthos (MPB) biomass in intertidal mudflats and has greatly improved our knowledge of MPB spatio-temporal variability and its potential drivers. Processes operating on smaller scales however, such as the impact of benthic macrofauna on MPB development, to date remain underinvestigated. In this study, we analysed the influence of wild Crassostrea gigas oyster reefs on MPB biofilm development using multispectral RS. A 30-year time series (1985-2015) combining high-resolution (30 m) Landsat and SPOT data was built in order to explore the relationship between C. gigas reefs and MPB spatial distribution and seasonal dynamics, using the normalized difference vegetation index (NDVI). Emphasis was placed on the analysis of a before-after control-impact (BACI) experiment designed to assess the effect of oyster killing on the surrounding MPB biofilms. Our RS data reveal that the presence of oyster reefs positively affects MPB biofilm development. Analysis of the historical time series first showed the presence of persistent, highly concentrated MPB patches around oyster reefs. This observation was supported by the BACI experiment which showed that killing the oysters (while leaving the physical reef structure, i.e. oyster shells, intact) negatively affected both MPB biofilm biomass and spatial stability around the reef. As such, our results are consistent with the hypothesis of nutrient input as an explanation for the MPB growth-promoting effect of oysters, whereby organic and inorganic matter released through oyster excretion and biodeposition stimulates MPB biomass accumulation. MPB also showed marked seasonal variations in biomass and patch shape, size and degree of aggregation around the oyster reefs. Seasonal variations in biomass, with higher NDVI during spring and autumn, were consistent with those observed on broader scales in other European mudflats. Our study provides the

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. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Perkinsus beihaiensis (Perkinsozoa) in oysters of Bahia State, Brazil.

PubMed

Luz, M S A; Carvalho, F S; Oliveira, H C; Boehs, G

2018-05-01

This study reports the pathogen Perkinsus beihaiensis in oysters of the genus Crassostrea on the coast of the State of Bahia (Brazil), its prevalence, infection intensity and correlation with salinity. Oysters (n = 240) were collected between October and December 2014 at eight sampling stations between latitudes 13°55'S and 15°42'S. The laboratory procedures included macroscopic analysis, histology, culture in Ray's fluid thioglycollate medium (RFTM), Polymerase Chain Reaction (PCR) and DNA sequencing. PCR and sequencing have been used for the genetic identification of oysters as well. Two species of oysters have been identified: Crassostrea rhizophorae and C. brasiliana. In both oyster species P. beihaiensis was the only Perkinsus species detected. In C. rhizophorae, the average prevalence was 82.8% by histology and 65.2% by RFTM. In C. brasiliana, the prevalences were 70.5% and 35.7%, respectively. The higher prevalence of P. beihaiensis in C. rhizophorae was probably influenced by salinity, with which was positively correlated (r> 0.8). In both oysters, P. beihaiensis was located mainly in the gastric epithelium. The infection was generally mild or moderate, without apparent harm to the hosts, but in cases of severe infection, there was hemocytical reaction and tissue disorganization. The generally high prevalence in the region suggests that oysters should be monitored with respect to this pathogen, especially in growing areas.

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

Inactivation and elimination of human enteric viruses by Pacific oysters.

PubMed

McLeod, C; Hay, B; Grant, C; Greening, G; Day, D

2009-12-01

To investigate the comparative elimination of three different human enterically transmitted viruses [i.e. hepatitis A virus (HAV), norovirus (NoV) and poliovirus (PV)] and inactivation of HAV and PV by Pacific oysters. New Zealand grown Pacific oysters (Crassostrea gigas) were allowed to bioaccumulate HAV, NoV and PV. Samples of oyster gut, faeces and pseudofaeces were then analysed by using real-time RT-PCR to determine the amount of viral RNA and cell culture methods to identify changes in the number of plaque forming units. The results suggest that the majority of the PV present in the oyster gut and oyster faeces is noninfectious, while in contrast, most of the HAV detected in the oyster gut are infectious. Depuration experiments identified a large drop in the count of PV in the gut over a 23-h cleansing period, whereas the levels of HAV and NoV did not significantly decrease. Human enterically transmitted viruses are eliminated and inactivated at different rates by Pacific oysters. The research presented in this article has implications for risk management techniques that are used to improve the removal of infectious human enteric viruses from bivalve molluscs.

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

USDA-ARS?s Scientific Manuscript database

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...

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

Bacteriophages as Biological Control Agents of Enteric Bacteria Contaminating Edible Oysters.

PubMed

Le, Tuan Son; Southgate, Paul C; O'Connor, Wayne; Poole, Sue; Kurtbӧke, D Ipek

2018-05-01

Bacterial contamination on seafood resulting from unhygienic food-handling practices causes foodborne diseases and significant revenue losses. Moreover, control measures are complicated by a high prevalence of antibiotic-resistant bacteria. Alternative measures such as the phage therapy, therefore, is considered as an environmental and consumer-friendly biological control strategy for controlling such bacterial contamination. In this study, we determined the effectiveness of a bacteriophage cocktail in controlling E. coli strains [JM 109, ATCC 13706 and the, extended spectrum beta-lactamase resistant strain (ATCC BAA 196)] and S. enterica subsp. enterica (ATCC 13311) as single and combined contaminants of the edible oysters. Five different E. coli-specific phages (belonging to the Siphoviridae family) and a Salmonella phage (belonging to the Tectiviridae family) were successfully isolated from sewage water samples taken from a local sewage treatment plan in the Sunshine Coast region of Australia. Phage treatments applied to the pathogens when they were presented on the oysters as either single or combined hosts, resulted in significant decrease of the number of these bacteria on edible oysters. Results obtained indicated that bacteriophages could have beneficial applications in oyster-processing plants in controlling pathogenic bacterial infestations. This study thus contributes towards ongoing international efforts into the effective use of bacteriophages for biological control purposes.

Analysis of Vibrio vulnificus Infection Risk When Consuming Depurated Raw Oysters.

PubMed

Deng, Kai; Wu, Xulei; Fuentes, Claudio; Su, Yi-Cheng; Welti-Chanes, Jorge; Paredes-Sabja, Daniel; Torres, J Antonio

2015-06-01

A beta Poisson dose-response model for Vibrio vulnificus food poisoning cases leading to septicemia was used to evaluate the effect of depuration at 15 °C on the estimated health risk associated with raw oyster consumption. Statistical variability sources included V. vulnificus level at harvest, time and temperature during harvest and transportation to processing plants, decimal reductions (SV) observed during experimental circulation depuration treatments, refrigerated storage time before consumption, oyster size, and number of oysters per consumption event. Although reaching nondetectable V. vulnificus levels (<30 most probable number per gram) throughout the year and a 3.52 SV were estimated not possible at the 95% confidence level, depuration for 1, 2, 3, and 4 days would reduce the warm season (June through September) risk from 2,669 cases to 558, 93, 38, and 47 cases per 100 million consumption events, respectively. At the 95% confidence level, 47 and 16 h of depuration would reduce the warm and transition season (April through May and October through November) risk, respectively, to 100 cases per 100 million consumption events, which is assumed to be an acceptable risk; 1 case per 100 million events would be the risk when consuming untreated raw oysters in the cold season (December through March).

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

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...

Neuropeptides encoded by the genomes of the Akoya pearl oyster Pinctata fucata and Pacific oyster Crassostrea gigas: a bioinformatic and peptidomic survey.

PubMed

Stewart, Michael J; Favrel, Pascal; Rotgans, Bronwyn A; Wang, Tianfang; Zhao, Min; Sohail, Manzar; O'Connor, Wayne A; Elizur, Abigail; Henry, Joel; Cummins, Scott F

2014-10-02

Oysters impart significant socio-ecological benefits from primary production of food supply, to estuarine ecosystems via reduction of water column nutrients, plankton and seston biomass. Little though is known at the molecular level of what genes are responsible for how oysters reproduce, filter nutrients, survive stressful physiological events and form reef communities. Neuropeptides represent a diverse class of chemical messengers, instrumental in orchestrating these complex physiological events in other species. By a combination of in silico data mining and peptide analysis of ganglia, 74 putative neuropeptide genes were identified from genome and transcriptome databases of the Akoya pearl oyster, Pinctata fucata and the Pacific oyster, Crassostrea gigas, encoding precursors for over 300 predicted bioactive peptide products, including three newly identified neuropeptide precursors PFGx8amide, RxIamide and Wx3Yamide. Our findings also include a gene for the gonadotropin-releasing hormone (GnRH) and two egg-laying hormones (ELH) which were identified from both oysters. Multiple sequence alignments and phylogenetic analysis supports similar global organization of these mature peptides. Computer-based peptide modeling of the molecular tertiary structures of ELH highlights the structural homologies within ELH family, which may facilitate ELH activity leading to the release of gametes. Our analysis demonstrates that oysters possess conserved molluscan neuropeptide domains and overall precursor organization whilst highlighting many previously unrecognized bivalve idiosyncrasies. This genomic analysis provides a solid foundation from which further studies aimed at the functional characterization of these molluscan neuropeptides can be conducted to further stimulate advances in understanding the ecology and cultivation of oysters.

Absorption and distribution of cadmium in mice fed diets containing either inorganic or oyster-incorporated cadmium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, M.F.; Hardy, J.T.; Miller, B.M.

1984-02-01

To determine the absorption, organ distribution, and retention of organically bound cadmium (Cd) and the effects of dietary zinc (Zn) on Cd metabolism, groups of mice were fed five different diets. The organic Cd used in the diets was in the form of lyophilized oyster (Crassostrea virginica) that had accumulated radiolabeled 109Cd through a plankton food chain. The mice were fed either a standard basal mouse diet (AIN-76) or diets containing five or eight times the Zn concentration of the basal diet. The source of Zn was either oyster tissue or ZnCO3. The concentration of organic and inorganic Cd providedmore » a dose of approximately 0.4 mg/kg. Diets prepared from oyster tissue probably contained all of the Cd and 85% of the Zn in organic form. Diets prepared with inorganic metals contained about the same Cd and Zn concentrations as the diets prepared with oyster. There was very little difference between the retention of Cd by mice that ingested organic (oyster bound) Cd and those fed inorganic Cd (CdCl2). However, when the Cd retained in the intestine was excluded, retention of organic Cd was significantly greater than that of inorganic Cd. The organ distribution of Cd differed significantly according to the chemical form of Cd fed (organic or inorganic) and the Zn level in the diet. The kidneys of mice fed organically bound Cd retained a higher percentage of the metal than the kidneys of those fed inorganic Cd. On the other hand, the livers of animals fed a low-Zn diet retained a higher percentage of the Cd than the livers of those fed a high-Zn diet, regardless of the dietary source of Cd.« less

Absence of surface-associated microorganisms in adult oysters (Crassostrea gigas).

PubMed Central

Garland, C D; Nash, G V; McMeekin, T A

1982-01-01

Healthy, actively feeding intertidal oysters were removed from an estuarine environment (Pipeclay Lagoon, Tasmania). The epithelial surfaces of various organs of the mantle cavity and alimentary tract were explored by scanning and transmission electron microscopy. All epithelial tissues examined were ciliated, and nearly all were partly covered with secreted mucus. However, microorganisms were seen rarely in the adhesive mucus and never attached to the epithelium. Electron microscopy also failed to demonstrate a surface microflora in emersed oysters which had been incubated at 5 to 25 degrees C for 6 or 24 h. The absence of an internal surface microflora did not vary on a seasonal basis. In laboratory experiments, oysters were allowed to filter feed from seawater containing diverse types of marine bacteria at concentrations of 10(3) to 10(7)/mL. However, no surface microflora could be found within actively feeding oysters or in emersed animals incubated at 20 degrees C for 6 or 24 h. In contrast, surface-associated microorganisms were detected readily by scanning electron microscopy on the external shell of healthy oysters and on various internal tissues in spoiled oysters. It is suggested that the major mechanisms restricting microbial growth within oysters are ciliary movement and mucus secretion. Images PMID:7181503

Does reef structure affect oyster food resources? A stable isotope assessment.

PubMed

Blomberg, Brittany N; Lebreton, Benoit; Palmer, Terence A; Guillou, Gaël; Beseres Pollack, Jennifer; Montagna, Paul A

2017-06-01

As ecosystem engineers, oysters create and maintain structured habitat and can influence trophodynamics and benthic-pelagic coupling in the surrounding landscape. The physical reef structure and associated biotic parameters can affect the availability of food resources for oysters. Oysters and potential composite food sources - suspended particulate organic matter (SPOM) and surface sediment organic matter (SSOM) - were assessed using a dual stable isotope (δ 13 C, δ 15 N) approach at three reef types (natural, restored, and unconsolidated) seasonally for two years to determine if changes in physical and/or biotic parameters affected the relative availability and/or use of food resources by oysters. SPOM was more depleted in 13 C (-24.2 ± 0.6‰, mean ± SD) than SSOM (-21.2 ± 0.8‰). SPOM composition is likely dominated by autochthonous phytoplankton production, while SSOM includes trapped phytoplankton and benthic microalgae. SSOM was used by oysters in increasing proportions relative to SPOM over time at all reef types. This temporal trend is likely due to increased oyster biomass over time, promoting enhanced microphytobenthos growth through feedback effects related to oyster biodeposits. Structural differences between reef types observed in this study had no effect on food resource availability and use by oysters, indicating strong bentho-pelagic coupling likely due to shallow depths as well as strong and consistent winds. This study provides insights for restoration of oyster reefs as it highlights that food resources used by oysters remain similar among reef types despite changes in abiotic and biotic parameters among habitats and over time. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecular confirmation of oysters as the vector for hepatitis A in a 2005 multistate outbreak.

PubMed

Shieh, Y C; Khudyakov, Y E; Xia, G; Ganova-Raeva, L M; Khambaty, F M; Woods, J W; Veazey, J E; Motes, M L; Glatzer, M B; Bialek, S R; Fiore, A E

2007-01-01

Numerous hepatitis A outbreaks were linked to the consumption of raw molluscan shellfish in the United States between 1960 and 1989. However, there had been no major molluscan shellfish-associated hepatitis A outbreaks reported in the United States for more than a decade (1989 to 2004). Beginning in late August 2005, at least 10 clusters of hepatitis A illnesses, totaling 39 persons, occurred in four states among restaurant patrons who ate oysters. Epidemiologic data indicated that oysters were the source of the outbreak. Traceback information showed that the implicated oysters were harvested from specific Gulf Coast areas. A voluntary recall of oysters was initiated in September. Hepatitis A virus (HAV) was detected in multiple 25-g portions in one of two recalled samples, indicating that as many as 1 of every 15 oysters from this source was contaminated. Comparing 315 nucleotides within the HAV VPl-2B region, 100% homology was found among four amplicons recovered from a total of six independent experiments of the implicated oysters, and an identical HAV sequence was detected in sera from all 28 patient serum specimens tested. Ten percent heterogeneity over 315 nucleotides (31 variants) was observed between the outbreak strain (subgenotype 1A) and an HM-175 strain (subgenotype 1B) used in the laboratory where the oysters were processed. To our knowledge, this investigation is the first in the United States to identify an HAV-identical strain in persons with hepatitis A as well as in the food that was implicated as the source of their infections.

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.

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...

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.

The contribution of oyster microbiomes to denitrification and nitrous oxide emissions in estuarine and coastal ecosystems

NASA Astrophysics Data System (ADS)

Arfken, A. M.; Song, B.; Smyth, A.

2016-02-01

Oysters are important nitrogen transformers in estuaries. Studies have shown that benthic-pelagic coupling by oysters stimulates sedimentary denitrification. The microbiomes living in and on oysters may also have high denitrification activity, generating N2O and N2 as end products. In order to evaluate the importance of oyster microbiome denitrification and its contribution to N2O emission in estuaries, continuous flow experiments with 15NO3- addition were conducted with oyster reef adjacent sediments, live oysters, live oysters with biofilm removed, and oyster shells. Denitrification rates were highest in live oysters, followed by scrubbed oysters, oyster shells, and finally by sediments, with the lowest activity. N2O production followed a similar trend, but with scrubbed oysters and shells being similar. We also found a significant linear correlation between N2 and N2O production, which indicates that denitrification is the source of N2O from oyster and oyster shells. Molecular analysis of microbiomes in oyster shells, guts and gills will be conducted using next generation sequencing of 16S rRNA gene and quantitative PCR assays targeting the functional genes in denitrification. We expect that within live oysters, the anaerobic gut microbiome will have higher abundances of denitrifiers than the shell biofilms or sediments, corresponding to higher denitrification activities in live oysters. This study will demonstrate that enhanced denitrification activity in oysters, in conjunction with sedimentary denitrification stimulated by oyster biodeposits, leads to oyster reefs being nitrogen removal hotspots and potential emission sources of N2O in estuarine and coastal ecosystems. In addition, the importance of microbiome structures in relation to oyster denitrification will be revealed.

Disturbance influences oyster community richness and evenness, but not diversity.

PubMed

Kimbro, David L; Grosholz, Edwin D

2006-09-01

Foundation species in space-limited systems can increase diversity by creating habitat, but they may also reduce diversity by excluding primary space competitors. These contrasting forces of increasing associate diversity and suppressing competitor diversity have rarely been examined experimentally with respect to disturbance. In a benthic marine community in central California, where native oysters are a foundation species, we tested how disturbance influenced overall species richness, evenness, and diversity. Surprisingly, overall diversity did not peak across a disturbance gradient because, as disturbance decreased, decreases in overall species evenness opposed increases in overall species richness. Decreasing disturbance intensity (high oyster abundance) led to increasing species richness of sessile and mobile species combined. This increase was due to the facilitation of secondary sessile and mobile species in the presence of oysters. In contrast, decreasing disturbance intensity and high oyster abundance decreased the evenness of sessile and mobile species. Three factors likely contributed to this decreased evenness: oysters reduced abundances of primary sessile species due to space competition; oysters supported more rare mobile species; and oysters disproportionately increased the relative abundance of a few common mobile species. Our results highlight the need for further studies on how disturbance can differentially affect the evenness and richness of different functional groups, and ultimately how these differences affect the relationship between overall diversity and ecosystem function.

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.

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

Antiviral Defense and Innate Immune Memory in the Oyster.

PubMed

Green, Timothy J; Speck, Peter

2018-03-16

The Pacific oyster, Crassostrea gigas , is becoming a valuable model for investigating antiviral defense in the Lophotrochozoa superphylum. In the past five years, improvements to laboratory-based experimental infection protocols using Ostreid herpesvirus I (OsHV-1) from naturally infected C. gigas combined with next-generation sequencing techniques has revealed that oysters have a complex antiviral response involving the activation of all major innate immune pathways. Experimental evidence indicates C. gigas utilizes an interferon-like response to limit OsHV-1 replication and spread. Oysters injected with a viral mimic (polyI:C) develop resistance to OsHV-1. Improved survival following polyI:C injection was found later in life (within-generational immune priming) and in the next generation (multi-generational immune priming). These studies indicate that the oyster's antiviral defense system exhibits a form of innate immune-memory. An important priority is to identify the molecular mechanisms responsible for this phenomenon. This knowledge will motivate the development of practical and cost-effective treatments for improving oyster health in aquaculture.

Streptomyces effect on the bacterial microbiota associated to Crassostrea sikamea oyster.

PubMed

García Bernal, M; Trabal Fernández, N; Saucedo Lastra, P E; Medina Marrero, R; Mazón-Suástegui, J M

2017-03-01

To determine the composition and diversity of the microbiota associated to Crassostrea sikamea treated during 30 days with Streptomyces strains N7 and RL8. DNA was extracted from oysters followed by 16S rRNA gene amplification and pyrosequencing. The highest and lowest species diversity richness was observed in the initial and final control group, whereas Streptomyces-treated oysters exhibited intermediate values. Proteobacteria was the most abundant phylum (81·4-95·1%), followed by Bacteroidetes, Actinobacteria and Firmicutes. The genera Anderseniella, Oceanicola, Roseovarius, Ruegeria, Sulfitobacter, Granulosicoccus and Marinicella encompassed the core microbiota of all experimental groups. The genus Bacteriovorax was detected in all groups except in the final control and the depurated N7, whereas Vibrio remained undetected in all Streptomyces-treated groups. RL8 was the only group that harboured the genus Streptomyces in its microbiota. Principal component analysis showed that Streptomyces strains significantly changed oyster microbiota with respect to the initial and final control. Crassostrea sikamea treated with Streptomyces showed high species diversity and a microbiota composition shift, characterized by keeping the predator genus Bacteriovorax and decreasing the pathogenic Vibrio. This is the first culture-independent study showing the effect of Streptomyces over the oyster microbiota. It also sheds light about the potential use of Streptomyces to improve mollusc health and safety for consumers after the depuration process. © 2016 The Society for Applied Microbiology.

Organic Stable Isotopes in Ancient Oyster Shell Trace Pre-colonial Nitrogen Sources

NASA Astrophysics Data System (ADS)

Darrow, E. S.; Carmichael, R. H.; Andrus, C. F. T.; Jackson, H. E.

2016-02-01

Oysters (Crassostrea virginica) were an important food resource for native peoples of the northern Gulf of Mexico, who harvested oysters and deposited waste shell and other artifacts in middens. Shell δ15N is a proxy for oyster tissue δ15N that reflects nitrogen (N) in food sources of bivalves. We tested the use of shell δ15N as a paleo proxy of ancient N sources, which to our knowledge has not been previously done for archeological bivalve specimens. To determine δ15N of the very low-N and high-carbonate ancient specimens, we tested established and modified acidification techniques developed for modern clams and oysters to decalcify organic shell matrix and extract sufficient N for analyses. Centrifugation following acidification better concentrated N from ancient shells for stable isotope analysis. Careful screening was required to detect effects of diagenesis, incomplete acidification, and sample contamination. Modern oyster shells did not require acidification and bulk shell material was directly analyzed for δ15N using an EA-IRMS coupled to a CO2 trap. δ15N values in ancient oyster shells did not differ from modern oyster shells from the same sites, but %N and % organic carbon (C) were lower in ancient than in modern shells. Organic δ13C in ancient shells had a significant negative relationship with shell age, possibly due to an effect of sea level rise increasing marine suspended particulate matter (SPM) sources to oysters. In modern oysters, δ15N had a significant relationship with soft tissue δ15N, and predicted by SPM δ15N, water column nitrate, and water column dissolved organic nitrogen (DON) concentrations, demonstrating the effectiveness of oyster shell δ15N to identify N sources to bivalves such as oysters. Our study has demonstrated the usefulness of δ15N from midden oyster shells as a proxy for N sources in an estuary that has undergone relatively light impacts from human land-use change through the past 2000 years.

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. Copyright © 2011 SETAC.

Development of a Simple Method for Concentrating Enteroviruses from Oysters

PubMed Central

Sobsey, Mark D.; Wallis, Craig; Melnick, Joseph L.

1975-01-01

The development of a simple method for concentrating enteroviruses from oysters is described. In this method viruses in homogenized oyster tissues are efficiently adsorbed to oyster solids at pH 5.5 and low salt concentration. After low-speed centrifugation, the supernatant is discarded and viruses are eluted from the sedimented oyster solids by resuspending them in pH 3.5 glycine-buffered saline. The solids are then removed by low-speed centrifugation, and the virus-containing supernatant is filtered through a 0.2-μm porosity filter to remove bacteria and other small particulates without removing viruses. The virus-containing filtrate is then concentrated to a volume of a few milliliters by ultrafiltration, and the concentrate obtained is inoculated directly into cell cultures for virus assay. When tested with pools of oysters experimentally contaminated with small amounts of different enteroviruses, virus recovery efficiency averaged 63%. PMID:234154

Development of a simple method for concentrating enteroviruses from oysters.

PubMed

Sobsey, M D; Wallis, C; Melnick, J L

1975-01-01

The development of a simple method for concentrating enteroviruses from oysters is described. In this method viruses in homogenized oyster tissues are efficiently absorbed to oyster solids at pH 5.5 and low salt concentration. After low-speed centrifugation, the supernatant is discarded and viruses are eluted from the sedimented oyster solids by resuspending them in pH 3.5 glycine-buffered saline. The solids are then removed by low-speed centrifugation, and the virus-containing supernatant is filtered through a 0.2-micronm porosity filter to remove bacteria and other small particulates without removing viruses. The virus-containing filtrate is then concentrated to a volume of a few milliliters by ultrafiltration, and the concentrate obtained is inoculated directly into cell cultures for virus assay. When tested with pools of oysters experimentally contaminated with small amounts of different enteroviruses, virus recovery efficiency averaged 63%.

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

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.

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.

Reducing oyster-associated bacteria levels using supercritical fluid CO2 as an agent of warm pasteurization.

PubMed

Meujo, Damaris A F; Kevin, Dion A; Peng, Jiangnan; Bowling, John J; Liu, Jianping; Hamann, Mark T

2010-03-31

An innovative approach to Post-Harvest Processing (PHP) of oysters is introduced focusing on the effects of supercritical carbon dioxide (scCO(2)) on bacterial contaminants trapped in the digestive system of oysters. Oysters were exposed to scCO(2) under two conditions: (1) 100 bar and 37 degrees C for 30 min and (2) 172 bar and 60 degrees C for 60 min. Using FDA standard guidelines for food analysis, variations in the Aerobic Plate Count (APC) were assessed. It was established that exposing oysters to CO(2) at 100 bar and 37 degrees C for 30 min and at 172 bar and 60 degrees C for 60 min induced 2-log and 3-log reductions in the APC respectively. The decrease in the microbial load as a result of treatment with scCO(2) was found to be significant (P=0.002). A release of adductor muscles from the shell was noted in oysters treated at 172 bar and 60 degrees C for 60 min; this was not the case for oysters treated at 100 bar and 37 degrees C for 30 min. A blind study allowing sensory analysis of treated vs. untreated oysters was also completed and no significant change in the physical appearance, smell, or texture was recorded. In this paper, we also report the effect of scCO(2) on several bacterial isolates, including a referenced ATCC strain of a non-pathogenic Vibrio (Vibrio fischeri) as well as several other bacterial isolates cultured from oyster' tissues and found to share biochemical features common to pathogenic Vibrio strains. A complete inactivation (minimum 7-log reduction) was achieved with these latter bacterial isolates. A 6-log reduction was observed with V. fischeri. Copyright 2009 Elsevier B.V. All rights reserved.

Recognizing the Operating Hand and the Hand-Changing Process for User Interface Adjustment on Smartphones.

PubMed

Guo, Hansong; Huang, He; Huang, Liusheng; Sun, Yu-E

2016-08-20

As the size of smartphone touchscreens has become larger and larger in recent years, operability with a single hand is getting worse, especially for female users. We envision that user experience can be significantly improved if smartphones are able to recognize the current operating hand, detect the hand-changing process and then adjust the user interfaces subsequently. In this paper, we proposed, implemented and evaluated two novel systems. The first one leverages the user-generated touchscreen traces to recognize the current operating hand, and the second one utilizes the accelerometer and gyroscope data of all kinds of activities in the user's daily life to detect the hand-changing process. These two systems are based on two supervised classifiers constructed from a series of refined touchscreen trace, accelerometer and gyroscope features. As opposed to existing solutions that all require users to select the current operating hand or confirm the hand-changing process manually, our systems follow much more convenient and practical methods and allow users to change the operating hand frequently without any harm to the user experience. We conduct extensive experiments on Samsung Galaxy S4 smartphones, and the evaluation results demonstrate that our proposed systems can recognize the current operating hand and detect the hand-changing process with 94.1% and 93.9% precision and 94.1% and 93.7% True Positive Rates (TPR) respectively, when deciding with a single touchscreen trace or accelerometer-gyroscope data segment, and the False Positive Rates (FPR) are as low as 2.6% and 0.7% accordingly. These two systems can either work completely independently and achieve pretty high accuracies or work jointly to further improve the recognition accuracy.

Global and local processing near the left and right hands

PubMed Central

Langerak, Robin M.; La Mantia, Carina L.; Brown, Liana E.

2013-01-01

Visual targets can be processed more quickly and reliably when a hand is placed near the target. Both unimodal and bimodal representations of hands are largely lateralized to the contralateral hemisphere, and since each hemisphere demonstrates specialized cognitive processing, it is possible that targets appearing near the left hand may be processed differently than targets appearing near the right hand. The purpose of this study was to determine whether visual processing near the left and right hands interacts with hemispheric specialization. We presented hierarchical-letter stimuli (e.g., small characters used as local elements to compose large characters at the global level) near the left or right hands separately and instructed participants to discriminate the presence of target letters (X and O) from non-target letters (T and U) at either the global or local levels as quickly as possible. Targets appeared at either the global or local level of the display, at both levels, or were absent from the display; participants made foot-press responses. When discriminating target presence at the global level, participants responded more quickly to stimuli presented near the left hand than near either the right hand or in the no-hand condition. Hand presence did not influence target discrimination at the local level. Our interpretation is that left-hand presence may help participants discriminate global information, a right hemisphere (RH) process, and that the left hand may influence visual processing in a way that is distinct from the right hand. PMID:24194725

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…

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.

Attention affects visual perceptual processing near the hand.

PubMed

Cosman, Joshua D; Vecera, Shaun P

2010-09-01

Specialized, bimodal neural systems integrate visual and tactile information in the space near the hand. Here, we show that visuo-tactile representations allow attention to influence early perceptual processing, namely, figure-ground assignment. Regions that were reached toward were more likely than other regions to be assigned as foreground figures, and hand position competed with image-based information to bias figure-ground assignment. Our findings suggest that hand position allows attention to influence visual perceptual processing and that visual processes typically viewed as unimodal can be influenced by bimodal visuo-tactile representations.

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

[Comparison of two nucleic acid extraction methods for norovirus in oysters].

PubMed

Yuan, Qiao; Li, Hui; Deng, Xiaoling; Mo, Yanling; Fang, Ling; Ke, Changwen

2013-04-01

To explore a convenient and effective method for norovirus nucleic acid extraction from oysters suitable for long-term viral surveillance. Two methods, namely method A (glycine washing and polyethylene glycol precipitation of the virus followed by silica gel centrifugal column) and method B (protease K digestion followed by application of paramagnetic silicon) were compared for their performance in norovirus nucleic acid extraction from oysters. Real-time RT-PCR was used to detect norovirus in naturally infected oysters and in oysters with induced infection. The two methods yielded comparable positive detection rates for the samples, but the recovery rate of the virus was higher with method B than with method A. Method B is a more convenient and rapid method for norovirus nucleic acid extraction from oysters and suitable for long-term surveillance of norovirus.

Using the Hands On Philosophy Daily in a Second Grade Classroom.

ERIC Educational Resources Information Center

Hammond, Pat

1988-01-01

Discusses student participation in many short-term projects related to regular study units in a second grade classroom. Describes projects of writing a class constitution, constructing a model colonial town, creating a mural of local colonial life, making corn shuck and apple-head dolls, and learning apple types grown locally. (DHP)

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

Reductions of Vibrio parahaemolyticus in Pacific oysters (Crassostrea gigas) by depuration at various temperatures.

PubMed

Phuvasate, Sureerat; Chen, Ming-Hui; Su, Yi-Cheng

2012-08-01

Consumption of raw oysters has been linked to several outbreaks of Vibrio parahaemolyticus infection in the United States. This study investigated effects of ice storage and UV-sterilized seawater depuration at various temperatures on reducing V. parahaemolyticus in oysters. Raw Pacific oysters (Crassostrea gigas) were inoculated with a mixed culture of five clinical strains of V. parahaemolyticus (10290, 10292, 10293, BE 98-2029 and 027-1c1) at levels of 10⁴⁻⁶ MPN/g. Inoculated oysters were either stored in ice or depurated in recirculating artificial seawater at 2, 3, 7, 10, 12.5, and 15 °C for 4-6 days. Holding oysters in ice or depuration of oysters in recirculating seawater at 2 or 3 °C for 4 days did not result in significant reductions (P > 0.05) of V. parahaemolyticus in the oysters. However, depuration at temperatures between 7 and 15 °C reduced V. parahaemolyticus populations in oysters by >3.0 log MPN/g after 5 days with no loss of oysters. Depuration at refrigerated temperatures (7-15 °C) can be applied as a post-harvest treatment for reducing V. parahaemolyticus in Pacific oysters. Copyright © 2012 Elsevier Ltd. All rights reserved.

Inducible variation in anaerobic energy metabolism reflects hypoxia tolerance across the intertidal and subtidal distribution of the Pacific oyster (Crassostrea gigas).

PubMed

Meng, Jie; Wang, Ting; Li, Li; Zhang, Guofan

2018-07-01

Pacific oyster (Crassostrea gigas) distribute a steep gradient of environmental stress between intertidal and subtidal habits and provide insight into population-scale patterns and underlying processes of variation in physiological tolerance. In this study, 1-year-old-F 1 oysters, collected from subtidal and intertidal habitats, were obtained after common garden experiment. Genetic differentiation and physiological responses under air exposure were examined to determine whether they had evolved into local adapted subpopulations. Mortality rate, anaerobic glycolysis metabolism, and energy status indicated that oyster had initiated metabolism depression and anaerobic glycolysis metabolism in both intertidal and subtidal oysters under air exposure. However, the subtidal oysters displayed the larger energy metabolism depressions and the earlier anaerobic glycolysis responses. This may indicate that subtidal oysters were more sensitives to hypoxia stress, which may lead the higher mortality rate under long term of air exposure. Based on a common garden experimental design, we propose that this diversification may have a genetic background. Overall, the clear differences between intertidal and subtidal oysters under air exposure have provided an important reference for their aquaculture and transportation used in commercial production. Copyright © 2018. Published by Elsevier Ltd.

Rapid methods for extraction and concentration of poliovirus from oyster tissues.

PubMed

Richards, G P; Goldmintz, D; Green, D L; Babinchak, J A

1982-12-01

A procedure is discussed for the extraction of poliovirus from oyster meats by modification of several enterovirus extraction techniques. The modified method uses meat extract and Cat-Floc, a polycationic electrolyte, for virus extraction and concentration. Virus recovery from inoculated oyster homogenates is 93-120%. Adsorption of viruses to oyster proteins by acidification of homogenates does not affect virus recovery. Elution of viruses from oyster proteins appears more efficient at pH 9.5 than at pH 8.0. This technique is relatively simple, economical and requires only 2.5 h to complete the combined extraction and concentration procedure.

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

USGS Publications Warehouse

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

2005-01-01

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

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). Copyright © 2013. Published by Elsevier Ltd.

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. © 2010, The International Biometric Society.

Real-time PCR quantification of Vibrio parahaemolyticus in oysters using an alternative matrix.

PubMed

Kaufman, G E; Blackstone, G M; Vickery, M C L; Bej, A K; Bowers, J; Bowen, Michael D; Meyer, Richard F; DePaola, A

2004-11-01

This study examined the relationship between levels of total Vibrio parahaemolyticus found in oyster tissues and mantle fluid with the goal of using mantle fluid as a template matrix in a new quantitative real-time PCR assay targeting the thermolabile hemolysin (tlh) gene for the enumeration of total V. parahaemolyticus in oysters. Oysters were collected near Mobile Bay, Ala., in June, July, and September and tested immediately after collection and storage at 26 degrees C for 24 h. Initial experiments using DNA colony hybridization targeting tlh demonstrated that natural V. parahaemolyticus levels in the mantle fluid of individual oysters were strongly correlated (r = 0.85, P < 0.05) with the levels found in their tissues. When known quantities of cultured V. parahaemolyticus cells were added to real-time PCR reactions that contained mantle fluid and oyster tissue matrices separately pooled from multiple oysters, a strong linear correlation was observed between the real-time PCR cycle threshold and the log concentration of cells inoculated into each PCR reaction (mantle fluid: r = 0.98, P < 0.05; and oyster: r = 0.99, P < 0.05). However, the mantle fluid exhibited less inhibition of the PCR amplification than the homogenized oyster tissue. Analysis of natural V. parahaemolyticus populations in mantle fluids using both colony hybridization and real-time PCR demonstrated a significant (P < 0.05) but reduced correlation (r = -0.48) between the two methods. Reductions in the efficiency of the real-time PCR that resulted from low population densities of V. parahaemolyticus and PCR inhibitors present in the mantle fluid of some oysters (with significant oyster-to-oyster variation) contributed to the reduction in correlation between the methods that was observed when testing natural V. parahaemolyticus populations. The V. parahaemolyticus-specific real-time PCR assay used for this study could estimate elevated V. parahaemolyticus levels in oyster mantle fluid within 1 h

The transcriptional response of the Pacific oyster Crassostrea gigas against acute heat stress.

PubMed

Yang, Chuanyan; Gao, Qiang; Liu, Chang; Wang, Lingling; Zhou, Zhi; Gong, Changhao; Zhang, Anguo; Zhang, Huan; Qiu, Limei; Song, Linsheng

2017-09-01

The Pacific oyster, Crassostrea gigas, has evolved sophisticated mechanisms to adapt the changing ambient conditions, and protect themselves from stress-induced injuries. In the present study, the expression profiles of mRNA transcripts in the haemocytes of oysters under heat stress were examined to reveal the possible mechanism of heat stress response. There were 23,315, 23,904, 23,123 and 23,672 transcripts identified in the haemocytes of oysters cultured at 25 °C for 0, 6, 12, and 24 h (designed as B, H6, H12, H24), respectively. And 22,330 differentially expressed transcripts (DTs) were yielded in the pairwise comparisons between the above four samples, which corresponded to 8074 genes. There were 9, 12 and 22 Gene Ontology (GO) terms identified in the DT pairwise comparison groups of H6_B, H12_H6 and H24_H12, respectively, and the richest GO terms in biological process category were cellular catabolic process, translational initiation and apoptotic process, respectively. There were 108, 102 and 102 KEGG pathways successfully retrieved from DTs comparison groups DTH6_B, DTH12_H6 and DTH24_H12, respectively, among which 93 pathways were shared by all three comparison groups, and most of them were related to metabolism of protein, carbohydrate and fat. The expression patterns of 12 representative heat stress response-relevant genes detected by quantitative real-time PCR (qRT-PCR) were similar to those obtained from transcriptome analysis. By flow cytometric analysis, the apoptosis rate of haemocytes increased significantly after oysters were treated at 25 °C for 24 h and recovered at 4 °C for 12 h (p < 0.05) and 36 h (p < 0.01), and it also increased significantly when the heat treatment lasted to 60 h (p < 0.01). The present results indicated that, when oysters encountered short term heat stress, the expression of genes related to energy metabolism, as well as unfolded protein response (UPR) and anti-apoptotic system, were firstly regulated to

National survey of foodborne viruses in Australian oysters at production.

PubMed

Torok, Valeria; Hodgson, Kate; McLeod, Catherine; Tan, Jessica; Malhi, Navreet; Turnbull, Alison

2018-02-01

Internationally human enteric viruses, such as norovirus (NoV) and hepatitis A virus (HAV), are frequently associated with shellfish related foodborne disease outbreaks, and it has been suggested that acceptable NoV limits based on end-point testing be established for this high risk food group. Currently, shellfish safety is generally managed through the use of indicators of faecal contamination. Between July 2014 and August 2015, a national prevalence survey for NoV and HAV was done in Australian oysters suitable for harvest. Two sampling rounds were undertaken to determine baseline levels of these viruses. Commercial Australian growing areas, represented by 33 oyster production regions in New South Wales, South Australia, Tasmania and Queensland, were included in the survey. A total of 149 and 148 samples were collected during round one and two of sampling, respectively, and tested for NoV and HAV by quantitative RT-PCR. NoV and HAV were not detected in oysters collected in either sampling round, indicating an estimated prevalence for these viruses in Australian oysters of <2% with a 95% confidence interval based on the survey design. The low estimated prevalence of foodborne viruses in Australian oysters was consistent with epidemiological evidence, with no oyster-related foodborne viral illness reported during the survey period. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Monitoring of trace elements in oysters marketed in Recife, Pernambuco, Brazil].

PubMed

Cavalcanti, André Dias

2003-01-01

Samples of oysters marketed in Recife, Pernambuco, Brazil, were monitored for the concentration of trace elements (Hg, Zn, Fe, Cu, and Mn) for one year (from March 2001 to February 2002). Mercury was the principal contaminant found in oysters and the element posing the greatest public health risk. Mercury levels in oysters reached 551.12 g/kg (wet weight). These values suggest that oyster consumption should be restricted, especially among communities that gather them as a subsistence activity, as well as by children and pregnant women. Evaluation of mercury concentration in seafood is an important factor for assessing the risk of contamination among individuals who are not occupationally exposed.

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.

Evaluating Ecosystem effects of oyster restoration in the Mississippi Sound

NASA Astrophysics Data System (ADS)

Klutse, C. K.; Milroy, S. P.

2016-02-01

Oyster reefs along the northern Gulf of Mexico are primarily formed by the eastern oyster, Crassostrea virginica, and are among the few biogenic natural habitats in the region. The increasing awareness of ecosystem services that habitat-forming bivalves provide, and the decline of the native species' population has led to a myriad of restoration efforts which have yielded varying results. Successful reef restoration efforts requires a deeper understanding of how variations in the timing and scales of environmental stressors control the survival, growth, and recruitment of reef associated species like oysters, shrimps, pelagic and benthic fish species. A modeling approach has been designed for exploring optimal growth conditions for oysters, studying the effect of seasonal trends in environmental stressors on the growth and survival of reef-associated species, and performing scenario testing for alternative restoration plans in the Mississippi Sound. The model uses a carbon budget approach, accounts for different functional groups within the trophic network on the reef, and operates on daily temporal resolution. Preliminary results indicate that restoration efforts may maximize benefits from the interactions between different salinity regimes and growth as well as mortality of oysters at three different class sizes of sacks, seeds, and spats. The study also seeks to evaluate the effects of different restoration efforts on promotion and recruitments in oyster populations as well as other reef-associated fishes and invertebrates. The current capabilities of the model can be scaled up to include evaluating changes in ecosystem goods and assessing their contributions to human well-being, the results of which will inform management decisions. Keywords: ecosystem modeling, oyster ecology, ecosystem-based management.

Recognizing the Operating Hand and the Hand-Changing Process for User Interface Adjustment on Smartphones †

PubMed Central

Guo, Hansong; Huang, He; Huang, Liusheng; Sun, Yu-E

2016-01-01

As the size of smartphone touchscreens has become larger and larger in recent years, operability with a single hand is getting worse, especially for female users. We envision that user experience can be significantly improved if smartphones are able to recognize the current operating hand, detect the hand-changing process and then adjust the user interfaces subsequently. In this paper, we proposed, implemented and evaluated two novel systems. The first one leverages the user-generated touchscreen traces to recognize the current operating hand, and the second one utilizes the accelerometer and gyroscope data of all kinds of activities in the user’s daily life to detect the hand-changing process. These two systems are based on two supervised classifiers constructed from a series of refined touchscreen trace, accelerometer and gyroscope features. As opposed to existing solutions that all require users to select the current operating hand or confirm the hand-changing process manually, our systems follow much more convenient and practical methods and allow users to change the operating hand frequently without any harm to the user experience. We conduct extensive experiments on Samsung Galaxy S4 smartphones, and the evaluation results demonstrate that our proposed systems can recognize the current operating hand and detect the hand-changing process with 94.1% and 93.9% precision and 94.1% and 93.7% True Positive Rates (TPR) respectively, when deciding with a single touchscreen trace or accelerometer-gyroscope data segment, and the False Positive Rates (FPR) are as low as 2.6% and 0.7% accordingly. These two systems can either work completely independently and achieve pretty high accuracies or work jointly to further improve the recognition accuracy. PMID:27556461

A norovirus outbreak associated with consumption of NSW oysters: implications for quality assurance systems.

PubMed

Huppatz, Clare; Munnoch, Sally A; Worgan, Tory; Merritt, Tony D; Dalton, Craig; Kelly, Paul M; Durrheim, David N

2008-03-01

Norovirus is a common cause of gastroenteritis outbreaks associated with raw shellfish consumption. In Australia there have been several reports of norovirus outbreaks associated with oysters despite the application of regulatory measures recommended by Food Standards Australia New Zealand. This study describes an outbreak of norovirus gastroenteritis following the consumption of New South Wales oysters. In September 2007, OzFoodNet conducted a cohort study of a gastroenteritis outbreak amongst people that had dined at a Port Macquarie restaurant. Illness was strongly associated with oyster consumption, with all cases having eaten oysters from the same lease (RR undefined, p < 0.0001). Norovirus was detected in a faecal specimen. Although no pathogen was identified during the environmental investigation, the source oyster lease had been closed just prior to harvesting due to sewage contamination. Australian quality assurance programs do not routinely test oysters for viral contamination that pose a risk to human health. It is recommended that the feasibility of testing oysters for norovirus, particularly after known faecal contamination of oyster leases, be assessed.

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

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.

Occurrence of marine algal toxins in oyster and phytoplankton samples in Daya Bay, South China Sea.

PubMed

Jiang, Tao; Liu, Lei; Li, Yang; Zhang, Jing; Tan, Zhijun; Wu, Haiyan; Jiang, Tianjiu; Lu, Songhui

2017-09-01

The occurrence and seasonal variations of marine algal toxins in phytoplankton and oyster samples in Daya Bay (DYB), South China Sea were investigated. Two Dinophysis species, namely, D. caudata and D. acuminata complex, were identified as Okadaic acid (OA)/pectenotoxin (PTX) related species. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis demonstrated that 2.04-14.47 pg PTX2 per cell was the predominant toxin in single-cell isolates of D. caudata. D. acuminata was not subjected to toxin analysis. The occurrence of OAs in phytoplankton concentrates of net-haul sample coincided with the presence of D. accuminata complex, suggesting that this species is most likely an OA producer in this sea area. OA, dinophysistoxins-1 (DTX1), PTX2, PTX2sa, gymnodimine (GYM), homoyessotoxin (homoYTX), and domoic acid (DA) demonstrated positive results in net haul samples. To our best knowledge, this paper is the first to report the detection of GYM, DA, and homoYTX in phytoplankton samples in Chinese coastal waters. Among the algal toxins, GYM demonstrated the highest frequency of positive detections in phytoplankton concentrates (13/17). Five compounds of algal toxins, including OA, DTX1, PTX2, PTX2sa, and GYM, were detected in oyster samples. DA and homoYTX were not detected in oysters despite of positive detections for both in the phytoplankton concentrates. However, neither the presence nor absence of DA in oysters can be determined because extraction conditions with 100% methanol used to isolate toxins from oysters (recommended by the EU-Harmonised Standard Operating Procedure, 2015) would likely be unsuitable for this water-soluble toxin. In addition, transformation of DA during the digestion process of oysters may also be involved in the negative detections of this toxin. GYM exhibited the highest frequency of positive results in oysters (14/17). OAs were only detected in the hydrolyzed oyster samples. The detection rates of PTX and PTX2sa in

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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.more » 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.« less

Reducing Oyster-Associated Bacteria Levels Using Supercritical Fluid CO2 as an Agent of Warm Pasteurization

PubMed Central

Meujo, Damaris A.F.; Kevin, Dion; Peng, Jiangnan; Bowling, John J.; Liu, Jianping; Hamann, Mark T.

2010-01-01

An innovative approach to Post-Harvest Processing (PHP) of oysters is introduced focusing on the effects of supercritical carbon dioxide (scCO2) on bacterial contaminants trapped in the digestive system of oysters. Oysters were exposed to scCO2 under two conditions: (1) 100 bar and 37 °C for 30 minutes and (2) 172 bar and 60 °C for 60 minutes. Using FDA standard guidelines for food analysis, variations in the Aerobic Plate Count (APC) was assessed. It was established that exposing oysters to CO2 at 100 bar and 37 °C for 30 minutes and at 172 bar and 60°C for 60 minutes induced 2-log and 3-log reductions in the APC respectively. The decrease in the microbial load as a result of treatment with scCO2 was found to be significant (P=0.002). A release of adductor muscles from the shell was noted in oysters treated at 172 bar and 60 °C for 60 minutes; this was not the case for oysters treated at 100 bar and 37 °C for 30 minutes. A blind study allowing sensory analysis of treated vs. untreated oysters was also completed and no significant change in the physical appearance, smell, or texture was recorded. In this paper, we also report the effect of scCO2 on several bacterial isolates, including a referenced ATCC strain of a non pathogenic Vibrio (V. fisherii) as well as several other bacterial isolates cultured from oyster’ tissues and found to share biochemical features common to pathogenic Vibrio strains. A complete inactivation (minimum 7-log reduction) was achieved with these latter bacterial isolates. A 6-log reduction was observed with V. fisherii. PMID:20022650

Effects of rigor status during high-pressure processing on the physical qualities of farm-raised abalone (Haliotis rufescens).

PubMed

Hughes, Brianna H; Greenberg, Neil J; Yang, Tom C; Skonberg, Denise I

2015-01-01

High-pressure processing (HPP) is used to increase meat safety and shelf-life, with conflicting quality effects depending on rigor status during HPP. In the seafood industry, HPP is used to shuck and pasteurize oysters, but its use on abalones has only been minimally evaluated and the effect of rigor status during HPP on abalone quality has not been reported. Farm-raised abalones (Haliotis rufescens) were divided into 12 HPP treatments and 1 unprocessed control treatment. Treatments were processed pre-rigor or post-rigor at 2 pressures (100 and 300 MPa) and 3 processing times (1, 3, and 5 min). The control was analyzed post-rigor. Uniform plugs were cut from adductor and foot meat for texture profile analysis, shear force, and color analysis. Subsamples were used for scanning electron microscopy of muscle ultrastructure. Texture profile analysis revealed that post-rigor processed abalone was significantly (P < 0.05) less firm and chewy than pre-rigor processed irrespective of muscle type, processing time, or pressure. L values increased with pressure to 68.9 at 300 MPa for pre-rigor processed foot, 73.8 for post-rigor processed foot, 90.9 for pre-rigor processed adductor, and 89.0 for post-rigor processed adductor. Scanning electron microscopy images showed fraying of collagen fibers in processed adductor, but did not show pressure-induced compaction of the foot myofibrils. Post-rigor processed abalone meat was more tender than pre-rigor processed meat, and post-rigor processed foot meat was lighter in color than pre-rigor processed foot meat, suggesting that waiting for rigor to resolve prior to processing abalones may improve consumer perceptions of quality and market value. © 2014 Institute of Food Technologists®

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.

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.

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

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 CO 2 environments are more resilient compared with those molluscs naive to CO 2 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-CO 2 world; either high-shore oysters will be more tolerant of elevated P CO 2 because of their regular acidosis, or elevated P CO 2  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 P CO 2 , and physiological variables were measured. The combined treatment of tidal emersion and elevated P CO 2  interacted synergistically to reduce the haemolymph pH (pH e ) of oysters, and increase the P CO 2  in the haemolymph ( P e,CO 2 ) 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-CO 2 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 P CO 2 . © 2017. Published by The Company of Biologists Ltd.

Oyster Larvae Settle in Response to Habitat-Associated Underwater Sounds

PubMed Central

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

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

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

The sense of hearing in the Pacific oyster, Magallana gigas.

PubMed

Charifi, Mohcine; Sow, Mohamedou; Ciret, Pierre; Benomar, Soumaya; Massabuau, Jean-Charles

2017-01-01

There is an increasing concern that anthropogenic noise could have a significant impact on the marine environment, but there is still insufficient data for most invertebrates. What do they perceive? We investigated this question in oysters Magallana gigas (Crassostrea gigas) using pure tone exposures, accelerometer fixed on the oyster shell and hydrophone in the water column. Groups of 16 oysters were exposed to quantifiable waterborne sinusoidal sounds in the range of 10 Hz to 20 kHz at various acoustic energies. The experiment was conducted in running seawater using an experimental flume equipped with suspended loudspeakers. The sensitivity of the oysters was measured by recording their valve movements by high-frequency noninvasive valvometry. The tests were 3 min tone exposures including a 70 sec fade-in period. Three endpoints were analysed: the ratio of responding individuals in the group, the resulting changes of valve opening amplitude and the response latency. At high enough acoustic energy, oysters transiently closed their valves in response to frequencies in the range of 10 to <1000 Hz, with maximum sensitivity from 10 to 200 Hz. The minimum acoustic energy required to elicit a response was 0.02 m∙s-2 at 122 dBrms re 1 μPa for frequencies ranging from 10 to 80 Hz. As a partial valve closure cannot be differentiated from a nociceptive response, it is very likely that oysters detect sounds at lower acoustic energy. The mechanism involved in sound detection and the ecological consequences are discussed.

New target tissue for food-borne virus detection in oysters.

PubMed

Wang, D; Wu, Q; Yao, L; Wei, M; Kou, X; Zhang, J

2008-11-01

To evaluate the different tissues of naturally contaminated oyster for food-borne virus detection. The different tissues of 136 field oyster samples were analysed for norovirus (NV), hepatitis A virus (HAV) and rotavirus (RV) by reverse transcription (RT)-PCR and were confirmed by sequencing. These viruses were detected in 20 samples (14.71%), showing positivity for NV (1.47%), HAV (5.15%) and RV (8.82%). Furthermore, among different tissues, the highest positive rate of the food-borne viruses was found in the gills (14.71%), followed by the stomach (13.97%) and the digestive diverticula (13.24%). The food-borne viruses were detected in the gills, stomach, digestive diverticula and the cilia of the mantle. In addition, the results showed that the gills are one of the appropriate tissues for viral detection in oysters by nucleic acid assay. This is the first paper to report on the presence of food-borne viruses in the gills and the cilia of the mantle of naturally contaminated oysters. The research team hopes that the results of the study will be of help in sampling the appropriate tissues for the detection of food-borne viruses in commercial oysters.

Clonal population structures are derived from various population processes in the protistan oyster parasite Perkinsus marinus

USDA-ARS?s Scientific Manuscript database

Population genetic analysis of genotypes comprised of seven microsatellite loci revealed clonal genetic patterns in each of four populations of the protistan estuarine parasite Perkinsus marinus. Each locus was amplified directly from DNA extracted from infected oysters collected from four geographi...

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.

Investigations of Salmonella enterica Serovar Newport Infections of Oysters by Using Immunohistochemistry and Knockout Mutagenesis

PubMed Central

Morrison, Christopher M.; Dial, Sharon M.; Day, William A.

2012-01-01

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. PMID:22307286

Reproductive responses and detoxification of estuarine oyster Crassostrea hongkongensis under metal stress: a seasonal study.

PubMed

Weng, Nanyan; Wang, Wen-Xiong

2015-03-03

Understanding the impacts of metal stress on the reproduction of dominant species, such as oysters, in seriously contaminated estuarine environments has great ecological implications. In the present study, the reproductive conditions were examined monthly for 1 year in oysters Crassostrea hongkongensis from a heavily metal-contaminated site (Baijiao, mainly by Cu and Zn) in the Jiulong River estuary and a relatively clean nearby estuary (Jiuzhen). Oysters sampled in the contaminated site showed a delayed gametogenesis, a relatively shorter spawning period, and a lower gonad condition index in comparison to the oysters sampled in the reference site. In particular, we found that the proportion of females increased significantly in the contaminated oysters, which provided the first evidence that the feminization in wild oyster populations could be related to trace metal pollution. Additionally, the potential detoxification mechanism of trace metals in oysters was also investigated. Compartmentalization of trace metals in membrane-limited vesicles in hemocytes could be an important detoxification mechanism for the contaminated oysters. Our findings indicated that the long-term metal exposure may greatly influence the reproduction of the oysters and finally affect the recruitment and population of this species.

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…

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.

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.

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

Suitability of oyster restoration sites along the Louisiana coast: Examining site and stock × site interaction

USGS Publications Warehouse

Schwarting Miller, Lindsay; La Peyre, Jerome F.; LaPeyre, Megan K.

2017-01-01

Recognition of the global loss of subtidal oyster reefs has led to a rise in reef restoration efforts, including in the Gulf of Mexico. Created reef success depends entirely on selecting a location that supports long-term oyster growth and survival, including the recruitment and survival of on-reef oysters. Significant changes in estuarine salinity through management of freshwater inflows and through changed precipitation patterns may significantly impact the locations of optimal oyster restoration sites. These rapid shifts in conditions necessitate a need to better understand both impacts to on-reef oyster growth and population development, and variation in oyster stock performance. Oyster growth, mortality, condition, and disease prevalence were examined in three different stocks of oysters located in protected cages, as well as oyster recruitment and mortality on experimental reef units in three different locations representing a salinity gradient, along the Louisiana Gulf coast in 2011 and 2012. Over a 2-y period, the high-salinity site had highest oyster growth rate in protected cages but demonstrated the least likelihood for reef development based on on-reef oyster population failure, likely because of predation-related mortality (high recruitment and 100% mortality). In contrast, the midsalinity site with moderate oyster growth and on-reef recruitment and low mortality demonstrated a higher likelihood for reef development. The lowest salinity site exhibited extreme variability in all oyster responses between years because of extreme variation in environmental conditions during the study, indicating a low likelihood of long-term reef development. Whereas limited differences in stock performance between sites were found, the range of site environmental conditions tested was ultimately much lower than expected and may not have provided a wide enough range of conditions. In areas with limited, low recruitment, or rapidly changing environmental conditions

Microplastics in oysters Saccostrea cucullata along the Pearl River Estuary, China.

PubMed

Li, Heng-Xiang; Ma, Li-Sha; Lin, Lang; Ni, Zhi-Xin; Xu, Xiang-Rong; Shi, Hua-Hong; Yan, Yan; Zheng, Guang-Ming; Rittschof, Daniel

2018-05-01

As a transitional zone between riverine and marine environments, an estuary plays an important role for the sources, accumulation and transport of microplastics. Although estuarine environments are hotspots of microplastic pollution, the correlation between microplastic pollution and aquatic organisms is less known. Here we investigated microplastic pollution in wild oysters Saccostrea cucullata from 11 sampling sites along the Pearl River Estuary in South China. The microplastic abundances in oysters ranged from 1.4 to 7.0 items per individual or from 1.5 to 7.2 items per gram tissue wet weight, which were positively related to those in surrounding waters. The oysters near urban areas contained significantly more microplastics than those near rural areas. Fibers accounted for 69.4% of the total microplastics in oysters. Microplastic sizes varied from 20 to 5000 μm and 83.9% of which were less than 100 μm. Light color microplastics were significantly more common than dark color ones. Based on the results, oysters are recommended as a biomonitor for the microplastic pollution in estuaries. Copyright © 2018 Elsevier Ltd. All rights reserved.

Oyster reproduction is compromised by acidification experienced seasonally in coastal regions.

PubMed

Boulais, Myrina; Chenevert, Kyle John; Demey, Ashley Taylor; Darrow, Elizabeth S; Robison, Madison Raine; Roberts, John Park; Volety, Aswani

2017-10-16

Atmospheric carbon dioxide concentrations have been rising during the past century, leading to ocean acidification (OA). Coastal and estuarine habitats experience annual pH variability that vastly exceeds the magnitude of long-term projections in open ocean regions. Eastern oyster (Crassostrea virginica) reproduction season coincides with periods of low pH occurrence in estuaries, thus we investigated effects of moderate (pH 7.5, pCO 2 2260 µatm) and severe OA (pH 7.1, pCO 2 5584 µatm; and 6.7, pCO 2 18480 µatm) on oyster gametogenesis, fertilization, and early larval development successes. Exposure at severe OA during gametogenesis caused disruption in oyster reproduction. Oogenesis appeared to be more sensitive compared to spermatogenesis. However, Eastern oyster reproduction was resilient to moderate OA projected for the near-future. In the context of projected climate change exacerbating seasonal acidification, OA of coastal habitats could represent a significant bottleneck for oyster reproduction which may have profound negative implications for coastal ecosystems reliant on this keystone species.

Monthly changes of glycogen, lipid and free amino acid of oyster

NASA Astrophysics Data System (ADS)

Zhicui, Zhang; Changhu, Xue; Xin, Gao; Zhaojie, Li; Qi, Wang

2006-07-01

Monthly difference of the chemical composition of oyster cultured along the eastern coast of Shandong Province was analyzed. The components analyzed included glycogen, fatty acid and free amino acid (FAA). The content of glycogen was high in January and March (2.89 and 2.82 g(100g)-1 on average, respectively) and low in October (2.07 g(100g)-1 on avarage). The low content of neutral lipids in October reflected a relatively poor nutritional value of oyster (1.42 g(100 g)-1 on average). The main fatty acids of oyster were palmitic acid (16:0), oleic acid (18:1), eicosapentaenoic acid (EPA, 20: 5ω-3) and docosahexaenoic acid (DHA, 22:6ω-3). The major FAAs of oyster were Taurine, Glutamicacid, Glycin, Alanine, Arginine and Proline. Taurine was the most abundant FAA with its content ranging from 603 mg (100g)-1 to 1139 mg(100g)-1. The high contents of glycogen, polyunsaturated fatty acid and FAA showed that oyster cultured along the eastern coast of Shandong Province was nutritionally good in January and March.

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.

A Spirochaete is suggested as the causative agent of Akoya oyster disease by metagenomic analysis

PubMed Central

Yasuike, Motoshige; Fujiwara, Atushi; Nakamura, Yoji; Takano, Tomokazu; Takeuchi, Takeshi; Satoh, Noriyuki; Adachi, Yoshikazu; Tsuchihashi, Yasushi; Aoki, Hideo; Odawara, Kazushi; Iwanaga, Shunsuke; Kurita, Jun; Kamaishi, Takashi; Nakayasu, Chihaya

2017-01-01

Mass mortality that is acompanied by reddish browning of the soft tissues has been occurring in cultured pearl oyster, Pinctada fucata martensii. The disease is called Akoya oyster disease (AOD). Although spreading pattern of the disease and transmission experiments suggest that the disease is infectious, the causative agent has not yet been identified. We used shotgun and 16S rRNA-based metagenomic analysis to identify genes that are present specifically in affected oysters. The genes found only in diseased oysters were mostly bacterial origin, suggesting that the causative agent was a bacterial pathogen. This hypothesis was supported by the inhibition of AOD development in naïve oysters injected with the hemolymph of diseased animals followed immediately with penicillin bath-administration. Further analyses of the hemolymph and mantle specifically and universally detected genes of bacteria that belong to phylum Spirochaetes in diseased pearl oysters but not in healthy oysters. By in situ hybridization or immunostaining, a Brachyspira-like bacterium was observed in the smears of hemolymph from affected oysters, but not from healthy oysters. Phylogenetic analysis using 16S rRNA sequences showed that the presumptive causative bacterium was outside of but most closely related to family Brachyspiraceae. We propose ‘Candidatus Maribrachyspira akoyae’ gen. nov, sp nov., for this bacterium. PMID:28771537

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.

The sense of hearing in the Pacific oyster, Magallana gigas

PubMed Central

Charifi, Mohcine; Sow, Mohamedou; Ciret, Pierre; Benomar, Soumaya

2017-01-01

There is an increasing concern that anthropogenic noise could have a significant impact on the marine environment, but there is still insufficient data for most invertebrates. What do they perceive? We investigated this question in oysters Magallana gigas (Crassostrea gigas) using pure tone exposures, accelerometer fixed on the oyster shell and hydrophone in the water column. Groups of 16 oysters were exposed to quantifiable waterborne sinusoidal sounds in the range of 10 Hz to 20 kHz at various acoustic energies. The experiment was conducted in running seawater using an experimental flume equipped with suspended loudspeakers. The sensitivity of the oysters was measured by recording their valve movements by high-frequency noninvasive valvometry. The tests were 3 min tone exposures including a 70 sec fade-in period. Three endpoints were analysed: the ratio of responding individuals in the group, the resulting changes of valve opening amplitude and the response latency. At high enough acoustic energy, oysters transiently closed their valves in response to frequencies in the range of 10 to <1000 Hz, with maximum sensitivity from 10 to 200 Hz. The minimum acoustic energy required to elicit a response was 0.02 m∙s-2 at 122 dBrms re 1 μPa for frequencies ranging from 10 to 80 Hz. As a partial valve closure cannot be differentiated from a nociceptive response, it is very likely that oysters detect sounds at lower acoustic energy. The mechanism involved in sound detection and the ecological consequences are discussed. PMID:29069092

Study on elemental fingerprint of traditional marine Chinese medicine oysters from Jiaozhou Bay, China

NASA Astrophysics Data System (ADS)

Zheng, Yongjun; Zheng, Kang; Li, Yantuan

2012-09-01

In order to investigate the relationship between the trace elements and the characteristics of the oysters, we analyzed the trace elements present in the germplasm of oysters from different producing areas in the Jiaozhou Bay. The element fingerprints were established to reflect the elemental characteristics of the oysters. Concentration patterns of the elements were deciphered by principle component analysis (PCA) and hierarchical cluster analysis (HCA). The six regions were discriminated with accuracy using HCA and PCA based on the concentration of 16 trace elements. The elements were viewed as characteristic elements of the oysters and the fingerprints of these elements could be used to distinguish the quality of the oysters.

Markers associated with disease resistance in Eastern oysters, Crassostrea virginica

USDA-ARS?s Scientific Manuscript database

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...

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

USDA-ARS?s Scientific Manuscript database

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...

Persistence of Vibrio vulnificus in tissues of Gulf Coast oysters, Crassostrea virginica, exposed to seawater disinfected with UV light.

PubMed

Tamplin, M L; Capers, G M

1992-05-01

Vibrio vulnificus is an estuarine bacterium which can cause opportunistic infections in humans consuming raw Gulf Coast oysters, Crassostrea virginica. Although V. vulnificus is known as a ubiquitous organism in the Gulf of Mexico, its ecological relationship with C. virginica has not been adequately defined. The objective of the present study was to test the hypothesis that V. vulnificus is a persistent microbial flora of oysters and unamenable to traditional methods of controlled purification, such as UV light depuration. Experimental depuration systems consisted of aquaria containing temperature-controlled seawater treated with UV light and 0.2-microns-pore-size filtration. V. vulnificus was enumerated in seawater, oyster shell biofilms, homogenates of whole oyster meats, and tissues including the hemolymph, digestive region, gills, mantle, and adductor muscle. Results showed that depuration systems conducted at temperatures greater than 23 degrees C caused V. vulnificus counts to increase in oysters, especially in the hemolymph, adductor muscle, and mantle. Throughout the process, depuration water contained high concentrations of V. vulnificus, indicating that the disinfection properties of UV radiation and 0.2-microns-pore-size filtration were less than the rate at which V. vulnificus was released into seawater. Approximately 10(5) to 10(6) V. vulnificus organisms were released from each oyster per hour, with 0.05 to 35% originating from shell surfaces. These surfaces contained greater than 10(3) V. vulnificus organisms per cm2. In contrast, when depuration seawater was maintained at 15 degrees C, V. vulnificus was not detected in seawater and multiplication in oyster tissues was inhibited.

Persistence, Seasonal Dynamics and Pathogenic Potential of Vibrio Communities from Pacific Oyster Hemolymph

PubMed Central

Wendling, Carolin C.; Batista, Frederico M.; Wegner, K. Mathias

2014-01-01

Bacteria of the genus Vibrio occur at a continuum from free-living to symbiotic life forms, including opportunists and pathogens, that can contribute to severe diseases, for instance summer mortality events of Pacific oysters Crassostrea gigas. While most studies focused on Vibrio isolated from moribund oysters during mortality outbreaks, investigations of the Vibrio community in healthy oysters are rare. Therefore, we characterized the persistence, diversity, seasonal dynamics, and pathogenicity of the Vibrio community isolated from healthy Pacific oysters. In a reciprocal transplant experiment we repeatedly sampled hemolymph from adult Pacific oysters to differentiate population from site-specific effects during six months of in situ incubation in the field. We characterized virulence phenotypes and genomic diversity based on multilocus sequence typing in a total of 70 Vibrio strains. Based on controlled infection experiments we could show that strains with the ability to colonize healthy adult oysters can also have the potential to induce high mortality rates on larvae. Diversity and abundance of Vibrio varied significantly over time with highest values during and after spawning season. Vibrio communities from transplanted and stationary oysters converged over time, indicating that communities were not population specific, but rather assemble from the surrounding environment forming communities, some of which can persist over longer periods. PMID:24728233

Oyster toadfish (Opsanus tau) boatwhistle call detection and patterns within a large-scale oyster restoration site

PubMed Central

Bohnenstiehl, DelWayne R.; Eggleston, David B.; Kellogg, M. Lisa; Lyon, R. Patrick

2017-01-01

During May 2015, passive acoustic recorders were deployed at eight subtidal oyster reefs within Harris Creek Oyster Sanctuary in Chesapeake Bay, Maryland USA. These sites were selected to represent both restored and unrestored habitats having a range of oyster densities. Throughout the survey, the soundscape within Harris Creek was dominated by the boatwhistle calls of the oyster toadfish, Opsanus tau. A novel, multi-kernel spectral correlation approach was developed to automatically detect these boatwhistle calls using their two lowest harmonic bands. The results provided quantitative information on how call rate and call frequency varied in space and time. Toadfish boatwhistle fundamental frequency ranged from 140 Hz to 260 Hz and was well correlated (r = 0.94) with changes in water temperature, with the fundamental frequency increasing by ~11 Hz for every 1°C increase in temperature. The boatwhistle call rate increased from just a few calls per minute at the start of monitoring on May 7th to ~100 calls/min on May 10th and remained elevated throughout the survey. As male toadfish are known to generate boatwhistles to attract mates, this rapid increase in call rate was interpreted to mark the onset of spring spawning behavior. Call rate was not modulated by water temperature, but showed a consistent diurnal pattern, with a sharp decrease in rate just before sunrise and a peak just after sunset. There was a significant difference in call rate between restored and unrestored reefs, with restored sites having nearly twice the call rate as unrestored sites. This work highlights the benefits of using automated detection techniques that provide quantitative information on species-specific call characteristics and patterns. This type of non-invasive acoustic monitoring provides long-term, semi-continuous information on animal behavior and abundance, and operates effectively in settings that are otherwise difficult to sample. PMID:28792543

Oyster toadfish (Opsanus tau) boatwhistle call detection and patterns within a large-scale oyster restoration site.

PubMed

Ricci, Shannon W; Bohnenstiehl, DelWayne R; Eggleston, David B; Kellogg, M Lisa; Lyon, R Patrick

2017-01-01

During May 2015, passive acoustic recorders were deployed at eight subtidal oyster reefs within Harris Creek Oyster Sanctuary in Chesapeake Bay, Maryland USA. These sites were selected to represent both restored and unrestored habitats having a range of oyster densities. Throughout the survey, the soundscape within Harris Creek was dominated by the boatwhistle calls of the oyster toadfish, Opsanus tau. A novel, multi-kernel spectral correlation approach was developed to automatically detect these boatwhistle calls using their two lowest harmonic bands. The results provided quantitative information on how call rate and call frequency varied in space and time. Toadfish boatwhistle fundamental frequency ranged from 140 Hz to 260 Hz and was well correlated (r = 0.94) with changes in water temperature, with the fundamental frequency increasing by ~11 Hz for every 1°C increase in temperature. The boatwhistle call rate increased from just a few calls per minute at the start of monitoring on May 7th to ~100 calls/min on May 10th and remained elevated throughout the survey. As male toadfish are known to generate boatwhistles to attract mates, this rapid increase in call rate was interpreted to mark the onset of spring spawning behavior. Call rate was not modulated by water temperature, but showed a consistent diurnal pattern, with a sharp decrease in rate just before sunrise and a peak just after sunset. There was a significant difference in call rate between restored and unrestored reefs, with restored sites having nearly twice the call rate as unrestored sites. This work highlights the benefits of using automated detection techniques that provide quantitative information on species-specific call characteristics and patterns. This type of non-invasive acoustic monitoring provides long-term, semi-continuous information on animal behavior and abundance, and operates effectively in settings that are otherwise difficult to sample.

Predicting the impacts of Mississippi River diversions and sea-level rise on spatial patterns of eastern oyster growth rate and production

USGS Publications Warehouse

Wang, Hongqing; Chen, Qin; La Peyre, Megan K.; Hu, Kelin; La Peyre, Jerome F.

2017-01-01

There remains much debate regarding the perceived tradeoffs of using freshwater and sediment diversions for coastal restoration in terms of balancing the need for wetland restoration versus preserving eastern oyster (Crassostrea virginica) production. Further complicating the issue, climate change-induced sea-level rise (SLR) and land subsidence are also expected to affect estuarine water quality. In this study, we developed a process-based numerical modeling system that couples hydrodynamic, water quality, and oyster population dynamics. We selected Breton Sound Estuary (BSE) (∼2740 km2) in the eastern Mississippi River Deltaic Plain since it is home to several of the largest public oyster seed grounds and private leases for the Gulf coast. The coupled oyster population model was calibrated and validated against field observed oyster growth data. We predicted the responses of oyster population in BSE to small- (142 m3 s−1) and large-scale (7080 m3 s−1) river diversions at the Caernarvon Freshwater Diversion structure planned in the 2012 Coastal Master Plan (Louisiana) under low (0.38 m) and high (1.44 m) relative sea-level rise (RSLR = eustatic SLR + subsidence) compared to a baseline condition (Year 2009). Model results showed that the large-scale diversion had a stronger negative impact on oyster population dynamics via freshening of the entire estuary, resulting in reduced oyster growth rate and production than RSLR. Under the large-scale diversion, areas with optimal oyster growth rates (>15 mg ash-free dry weight (AFDW) oyster−1 wk−1) and production (>500 g AFDW m−2 yr−1) would shift seaward to the southeastern edge of the estuary, turning the estuary into a very low oyster production system. RSLR however played a greater role than the small-scale diversion on the magnitude and spatial pattern of oyster growth rate and production. RSLR would result in an overall estuary-wide decrease in oyster growth rate and production as a

Chemical elements in pearl oysters (Paxyodon ponderosus), phytoplankton and estuarine sediments from eastern Amazon (Northern Brazil): Bioaccumulation factors and trophic transfer factors

NASA Astrophysics Data System (ADS)

Vilhena, Maria P. S. P.; Costa, Marcondes L.; Berrêdo, José F.; Paiva, Rosildo S.; Souza, Crisvaldo C. S.

2016-04-01

The current study was conducted near Barcarena County, which is a mid-sized urban center where aluminum ore processing industries (bauxite) and Vila do Conde cargo terminal are located. It aims to discuss the bioaccumulation factors as well as factors related to the trophic transfer of chemical elements in water, oyster, phytoplankton and bottom sediments from an estuary in the Brazilian Northern coast. The bioaccumulation factor (BAF), trophic transfer factor (TTF) and biota-sediment-water were used to correlate the contents of chemical elements found in organisms. The sediment, surface water, phytoplankton and pearl oysters chemical composition was analyzed by ICP-OES and ICP-MS. Pearl oysters showed K, Ca, Mg, P, Mn, Fe, Zn, Al, Ba and Pb accumulation, which concentration increase is associated with their diet (phytoplankton). Al concentrations are 14 times higher in pearl oysters (Paxyodon ponderosus), assuming that they are associated with wastewater emissions and with industrialization processes in the area. BAF and BSAF values are 1000 times higher than the metal concentrations in water and bioavailable fraction concentrations. The oyster-phytoplankton trophic transfer factor indicates that P, Ba, Ca, Na, Cd and Zn showed the largest transfers (from 5 to 19). These trophic transfers may be sufficient to cause significant ecotoxicological effects on the region biota.

Contribution of in Vivo Experimental Challenges to Understanding Flat Oyster Ostrea edulis Resistance to Bonamia ostreae

PubMed Central

Morga, Benjamin; Renault, Tristan; Faury, Nicole; Lerond, Sophie; Garcia, Céline; Chollet, Bruno; Joly, Jean-Pierre; Lapègue, Sylvie; Harrang, Estelle; Arzul, Isabelle

2017-01-01

Bonamiosis due to the parasite Bonamia ostreae has been associated with massive mortality outbreaks in European flat oyster stocks in Europe. As eradication and treatment are not possible, the control of the disease mainly relies on transfer restriction. Moreover, selection has been applied to produce resistant flat oyster families, which present better survival and lower prevalence than non-selected oysters. In order to better understand the mechanisms involved in resistance to bonamiosis, cellular and molecular responses of 2 oyster groups (selected oysters and wild-type oysters) were analyzed in the context of experimental injection and cohabitation infections. Cellular responses including non-specific esterases detection, ROS production and phagocytosis activity were analyzed by flow cytometry. Four genes homologous to those shown to be involved in immunity were selected (Inhibitor of apotosis OeIAP, Fas ligand OeFas-ligand, Oe-SOD, and OeEc-SOD) and monitored by quantitative reverse-transcription PCR (qRT-PCR). Infected oysters showed higher phagocytosis activity than controls. Infected selected oyster show a lower phagocytosis activity which might be a protection against the parasite infection. The expression of OeIAP and OeFas-ligand gene was significantly increased in selected oysters at 5 days post-injection. OeIAP gene expression appeared to be significantly increased in wild-type oysters at 8 days post-injection. Our results suggest that resistance to bonamiosis partly relies on the ability of the oysters to modulate apoptosis. PMID:29057216

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...

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

Behavior of pathogenic bacteria in the oyster, Crassostrea commercialis, during depuration, re-laying, and storage.

PubMed

Son, N T; Fleet, G H

1980-12-01

Oysters (Crassostrea commercials) harvested from major cultivation areas within the state of New South Wales, Australia, were commonly contaminated with low levels of the food-poisoning organisms Bacillus cereus, Clostridium perfringens, and Vibrio parahaemolyticus. Salmonella was found in oysters on only one occasion. These bacteria were cleansed from oysters during oyster purification by re-laying in a non-polluted waterway. Oysters were laboratory contaminated to levels in excess 1,000 cells per g with either B. cereus, C. perfringens, V. parahaemolyticus, Salmonella typhimurium, or S. senftenberg. These species were cleansed from such oysters during purification in a laboratory depuration unit that used ultraviolet light for sterilizing the depuration water. Escherichia coli was also cleansed from oysters under the same re-laying or depuration conditions so that its measurement alone could be used to indicate the cleansing of the above pathogenic species. The levels of these bacteria were also measured during the storage of oysters under conditions that occur during marketing. While B. cereus counts remained relatively stable during storage, the Salmonella spp. gradually decreased in numbers and C. perfringens rapidly died off. V. parahaemolyticus counts increased slightly during the first 4 days of storage, after which decreases occurred.

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% CO 2 : 50% N 2 , 70% CO 2 : 30% O 2 , and 50% CO 2 : 50% O 2 ) 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 CO 2 :O 2 (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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

A cytokine-like factor astakine accelerates the hemocyte production in Pacific oyster Crassostrea gigas.

PubMed

Li, Yiqun; Jiang, Shuai; Li, Meijia; Xin, Lusheng; Wang, Lingling; Wang, Hao; Qiu, Limei; Song, Linsheng

2016-02-01

Astakine has been reported to be a hematopoietic growth factor of prokineticin homolog firstly found in arthropods freshwater crayfish Pacifastacus leniusculus. In the present study, an astakine homologous gene was identified from Pacific oyster Crassostrea gigas (designated CgAstakine). The full length cDNA of CgAstakine encoded a polypeptide of 103 amino acids containing a prokineticin (PK) domain homologous to that in astakine from freshwater crayfish P. leniusculus. The deduced amino acid sequence of CgAstakine shared higher similarity with those of other invertebrate astakines than prokineticins from vertebrates. The mRNA of CgAstakine was highly expressed in hepatopancreas and adductor muscle of oyster, while the CgAstakine protein was mainly distributed in hepatopancreas, gill and hemocytes. The mRNA expression of CgAstakine in hemocytes was significantly increased (p < 0.01) and maintained at a high level from 3 h to 9 h after Vibrio anguillarum challenge. After the oyster hemocytes were incubated with 5 μg/mL recombinant CgAstakine protein (rCgAstakine) for 24 h in vitro, the proliferation of hemocytes was significantly increased to 1.89 fold of that in control group (p < 0.05). Moreover, the total count of oyster hemocytes was significantly upregulated (2.45 fold of that in control group, p < 0.05) at 12 h after the oysters were received an injection of rCgAstakine (0.5 μg/g). These results collectively indicated that CgAstakine could modulate the hemocytes proliferation both in vitro and in vivo, and probably involved in the hematopoietic process fighting against the invasion of foreign pathogens. Copyright © 2015 Elsevier Ltd. All rights reserved.

Temperature, energy metabolism, and adaptive divergence in two oyster subspecies.

PubMed

Li, Ao; Li, Li; Song, Kai; Wang, Wei; Zhang, Guofan

2017-08-01

Comparisons of related species that have diverse spatial distributions provide an efficient way to investigate adaptive evolution in face of increasing global warming. The oyster subjected to high environmental selections is a model species as sessile marine invertebrate. This study aimed to detect the adaptive divergence of energy metabolism in two oyster subspecies from the genus Crassostrea - C. gigas gigas and C. gigas angulata -which are broadly distributed along the northern and southern coasts of China, respectively. We examined the effects of acute thermal stress on energy metabolism in two oyster subspecies after being common gardened for one generation in identical conditions. Thermal responses were assessed by incorporating physiological, molecular, and genomic approaches. Southern oysters exhibited higher fluctuations in metabolic rate, activities of key energetic enzymes, and levels of thermally induced gene expression than northern oysters. For genes involved in energy metabolism, the former displayed higher basal levels of gene expression and a more pronounced downregulation of thermally induced expression, while the later exhibited lower basal levels and a less pronounced downregulation of gene expression. Contrary expression pattern was observed in oxidative stress gene. Besides, energy metabolic tradeoffs were detected in both subspecies. Furthermore, the genetic divergence of a nonsynonymous SNP ( SOD-132 ) and five synonymous SNPs in other genes was identified and validated in these two subspecies, which possibly affects downstream functions and explains the aforementioned phenotypic variations. Our study demonstrates that differentiations in energy metabolism underlie the plasticity of adaptive divergence in two oyster subspecies and suggest C. gigas angulata with moderate phenotypic plasticity has higher adaptive potential to cope with exacerbated global warming.

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. © 2016 John Wiley & Sons Ltd.

Oysters and eelgrass: potential partners in a high pCO2 ocean.

PubMed

Groner, Maya L; Burge, Colleen A; Cox, Ruth; Rivlin, Natalie; Turner, Mo; Van Alstyne, Kathryn L; Wyllie-Echeverria, Sandy; Bucci, John; Staudigel, Philip; Friedman, Carolyn S

2018-05-25

Climate change is affecting the health and physiology of marine organisms and altering species interactions. Ocean acidification (OA) threatens calcifying organisms such as the Pacific oyster, Crassostrea gigas. In contrast, seagrasses, such as the eelgrass Zostera marina, can benefit from the increase in available carbon for photosynthesis found at a lower seawater pH. Seagrasses can remove dissolved inorganic carbon from OA environments, creating local daytime pH refugia. Pacific oysters may improve the health of eelgrass by filtering out pathogens such as Labyrinthula zosterae (LZ), which causes eelgrass wasting disease (EWD). We examined how co-culture of eelgrass ramets and juvenile oysters affected the health and growth of eelgrass and the mass of oysters under different pCO 2 exposures. In Phase I, each species was cultured alone or in co-culture at 12°C across ambient, medium, and high pCO 2 conditions, (656, 1158 and1606 μatm pCO 2 , respectively). Under high pCO 2 , eelgrass grew faster and had less severe EWD (contracted in the field prior to the experiment). Co-culture with oysters also reduced the severity of EWD. While the presence of eelgrass decreased daytime pCO 2 , this reduction was not substantial enough to ameliorate the negative impact of high pCO 2 on oyster mass. In Phase II, eelgrass alone or oysters and eelgrass in co-culture were held at 15°C under ambient and high pCO 2 conditions, (488 and 2013 μatm pCO 2 , respectively). Half of the replicates were challenged with cultured LZ. Concentrations of defensive compounds in eelgrass (total phenolics and tannins), were altered by LZ exposure and pCO 2 treatments. Greater pathogen loads and increased EWD severity were detected in LZ exposed eelgrass ramets; EWD severity was reduced at high relative to low pCO 2 . Oyster presence did not influence pathogen load or EWD severity; high LZ concentrations in experimental treatments may have masked the effect of this treatment. Collectively, these

Offshore suspension relaying to reduce levels of Vibrio vulnificus in oysters (Crassostrea virginica).

PubMed

Motes, M L; DePaola, A

1996-10-01

Oysters naturally contaminated with 10(3) to 10(4) most probable numbers (MPN) of Vibrio vulnificus per g were relayed to offshore waters (salinity, 30 to 34 ppt), where they were suspended in racks at a depth of 7.6 m. V. vulnificus counts in oysters were reduced to < 10 MPN/g within 7 to 17 days in five of the six studies. At the end of the studies (17 to 49 days), V. vulnificus levels were reduced further and ranged from a mean of 0.23 to 2.6 MPN/g. Oyster mortalities during relaying were < 6%. The reduction of V. vulnificus in relayed oysters is associated with exposure to high-salinity environments essentially devoid of V. vulnificus. Offshore suspension relaying may be a method that industry can employ to reduce V. vulnificus levels in raw Gulf Coast oysters.

Temperature effect on high salinity depuration of Vibrio vulnificus and V. parahaemolyticus from the Eastern oyster (Crassostrea virginica).

PubMed

Larsen, A M; Rikard, F S; Walton, W C; Arias, C R

2015-01-02

Vibrio vulnificus (Vv) and Vibrio parahaemolyticus (Vp) are opportunistic human pathogens naturally associated with the Eastern oyster Crassostrea virginica. The abundances of both pathogens in oysters are positively correlated with temperature, thus ingestion of raw oysters during the warm summer months is a risk factor for contracting illness from these bacteria. Current post-harvest processing (PHP) methods for elimination of these pathogens are expensive and kill the oyster, changing their organoleptic properties and making them less appealing to some consumers. High salinity has proven effective in reducing Vv numbers in the wild and our research aims at developing an indoor recirculating system to reduce pathogenic Vibrios while maintaining the taste and texture of live oysters. The goal of this study was to determine the influence of temperature on the efficacy of high salinity depuration. Vv was enumerated as most probable number (MPN) per gram of oyster tissue using the FDA-approved modified cellobiose polymyxin colistin (mCPC) protocol and with an alternative Vibrio specific media CHROMagar™ Vibrio (CaV). CaV was also used to quantify Vp. Oysters were held at 35 psu for 10 days at three temperatures: low (20°C), mid (22.5°C) and high (25°C). There was no difference in MPN/g of Vv between media; however more Vv isolates were obtained from mCPC than CaV. There was no significant effect of temperature on reduction of Vv or Vp throughout depuration but there was a tendency for low temperatures to be less effective than the higher ones. High salinity resulted in a significant decrease in Vv by day 3 and again by day 10, and a decrease in Vp by day 3. Oyster condition indices were maintained throughout depuration and mortality was low (4% across three trials). Overall these results support the use of mCPC for Vv enumeration and demonstrate the promise of high salinity depuration for PHP of the Eastern oyster. The trend for lower temperatures to be less

[Phylogenetic analysis of tyrosinase gene family in the Pacific oyster (Crassostrea gigas Thunberg)].

PubMed

Yu, Xue; Yu, Hong; Kong, Lingfeng; Li, Qi

2014-02-01

The deduced amino acid sequence characteristics, classification and phylogeny of tyrosinase gene family in the Pacific oyster (Crassostrea gigas Thunberg) were analyzed using bioinformatics methods. The results showed that gene duplication was the major cause of tyrosinase gene expansion in the Pacific oyster. The tyrosinase gene family in the Pacific oyster can be further classified into three types: secreted form (Type A), cytosolic form (Type B) and membrane-bound form (Type C). Based on the topology of the phylogenetic tree of the Pacific oyster tyrosinases, among Type A isoforms, tyr18 seemed divergent from other Type A tyrosinases early, while tyr2 and tyr9 appeared divergent early in Type B. In Type C tyrosinses, tyr8 was divergent early. The cluster of the Pacific oyster tyrosinasesis determined by their classifications and positions in the scaffolds. Further analysis suggested that Type A tyrosinases of C. gigas clustered with those from cephalopods and then with nematodes and cnidarians. Type B tyrosinases were generally clustered with the same type of tyrosinases from molluscas and nematodes, and then with those from platyhelminths, cnidarians and chordates. Type A tyrosinases in the Pacific oyster and the Pearl oyster expanded independently and were divergent from membrane-bound form of tyrosinases in chordata, platyhelminthes and annelida. These observations suggested that Type C tyrosinases in the bivalve had a distinct evolution direction.

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. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

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

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-14

... Oyster Creek Nuclear Generating Station Environmental Assessment and Finding of No Significant Impact The... Company, LLC (the licensee), for operation of the Oyster Creek Nuclear Generating Station (Oyster Creek), located in Ocean County, New Jersey. Therefore, as required by 10 CFR Section 51.21, the NRC performed an...

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Behavior of pathogenic bacteria in the oyster, Crassostrea commercialis, during depuration, re-laying, and storage.

PubMed Central

Son, N T; Fleet, G H

1980-01-01

Oysters (Crassostrea commercials) harvested from major cultivation areas within the state of New South Wales, Australia, were commonly contaminated with low levels of the food-poisoning organisms Bacillus cereus, Clostridium perfringens, and Vibrio parahaemolyticus. Salmonella was found in oysters on only one occasion. These bacteria were cleansed from oysters during oyster purification by re-laying in a non-polluted waterway. Oysters were laboratory contaminated to levels in excess 1,000 cells per g with either B. cereus, C. perfringens, V. parahaemolyticus, Salmonella typhimurium, or S. senftenberg. These species were cleansed from such oysters during purification in a laboratory depuration unit that used ultraviolet light for sterilizing the depuration water. Escherichia coli was also cleansed from oysters under the same re-laying or depuration conditions so that its measurement alone could be used to indicate the cleansing of the above pathogenic species. The levels of these bacteria were also measured during the storage of oysters under conditions that occur during marketing. While B. cereus counts remained relatively stable during storage, the Salmonella spp. gradually decreased in numbers and C. perfringens rapidly died off. V. parahaemolyticus counts increased slightly during the first 4 days of storage, after which decreases occurred. PMID:6257164

Denman Island disease (causative agent Mikrocytos mackini) in a new host, Kumamoto oysters Crassostrea sikamea.

PubMed

Elston, Ralph A; Moore, James; Abbott, Cathryn L

2012-12-03

Mikrocytos mackini, causative agent of Denman Island disease in Pacific oysters Crassostrea gigas and other oyster species, was found in 2011 in a previously unreported host, the Kumamoto oyster C. sikamea, in Humboldt Bay, California, USA. The detection was also the first reported finding of M. mackini in California. Prevalence was estimated as high as approximately 27% from pooled samples analyzed by PCR. Higher prevalence appeared related to longer residence time in the bay and somewhat colder than typical winter seawater temperatures. No M. mackini was detected in Humboldt Bay juvenile Kumamoto oysters or Pacific oyster brood or seed stock in 2011 or 2012.

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.

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. Copyright © 2015 Elsevier Inc. All rights reserved.

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.

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.

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...

CHANGES IN THE MICROFLORA OF HADDOCK FILLETS AND SHUCKED SOFT-SHELLED CLAMS AFTER IRRADIATION WITH Co$sup 60$ GAMMA RAYS AND STORAGE TO 0 C AND 6 C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masurovsky, E.B.; Voss, J.S.; Goldblith, S.A.

1963-05-01

Microbiologic analyses were made on haddock fillets and shucked soft- shelled clams before and after treatment with doses of from 50000 to 800000 rad of Co/sup 60/ gamma rays. A decided change occurred in the constitution of the microbial populations of both products: from a mixed gram-negativegram-positive flora to a predominantly gram-positive flora immediately after irradiation. The majority of these surviving microorganisms were micrococci, spore-forming bacilli, yeasts, molds, and actinomyces. During storage at refrigeration temperatures above freezing, the microflora changed from the more radioresistant gram-positive species to the more prolific gram-negative psychrophilic species that flourish at low temperatures. Micrococci andmore » gram-positive rods declined somewhat during the rise of the actively proteolytic-lipolytic pseudomonads and related species, but still remained at high enough levels to contribute significantly to the spoilage observed at different times in storage. The eventual spoilage of haddock fillets was characterized by discoloration with water-soluble yellow, green, and red bacterial pigments; degradation of the tissue, by proteolytic and other microbial enzymes; and formation of volatile compounds that smelled putrid, rancid, and generally foul and pungent. Shucked soft-shelled clams displayed a different spoilage pattern, changing to a gelatinous mass with stale, acrid, putrid, sulfurous odor. These differences are attributable to the varied biochemical nature of the tissues involved, the Eh potential within the tissues, the time sequence of microfloral change, and the species and types of microorganisms associated with each product. Staphylococci were present in small numbers, but did not appear to be species of public health significance. Gram-negative enteric rods were also encountered, but were considered to be of doubtful public health importance. (BBB)« less

Salinity Tolerance of Early-Stage Oyster Larvae in the Choptank River, Chesapeake Bay, USA

NASA Astrophysics Data System (ADS)

Scharping, R. J.; North, E. W.; Plough, L. V.

2016-02-01

The eastern oyster (Crassostrea virginica) is ecologically and economically important to the Chesapeake Bay, Maryland, USA. Its population, however, is currently estimated to be less than one percent of what it was historically. To restore oyster populations, techniques such as larval transport modeling are being implemented to aid the selection of sanctuary locations. These models can incorporate biological factors such as salinity-induced mortality, but no data from low-salinity areas such as the oligohaline Choptank River, a major focus of oyster restoration in the Chesapeake, exist. The purpose of our study was to generate salinity-induced mortality data for oyster larvae from the Choptank River and compare their tolerances to those of oysters from different salinity regimes. We performed three experiments looking at the effect of salinities from 3 to 26 on the survival of larvae from 4 to 48 hrs post-fertilization. While overall survival differed across experiments, we found a consistent minimum survival threshold between 5-7 and peak survival window between 9-16. These salinity values were about 7 lower than those of oysters from the polyhaline Long Island Sound (threshold: 12.5-15; peak: 17.5-27). This research has direct application to oyster restoration in the Choptank River and similar low-salinity areas by improving larval transport model predictions.

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

Antioxidant and detoxification responses of oysters Crassostrea hongkongensis in a multimetal-contaminated estuary.

PubMed

Liu, Xuan; Wang, Wen-Xiong

2016-11-01

The contaminated oysters discovered in the Pearl River Estuary (Guangdong province, China) contained high levels of metals in their tissues, especially Cu and Zn, indicating that this large and densely urbanized estuary in Southern China suffers from serious metal pollution. The present study aimed to investigate the impacts of multimetal pollution in the Pearl River Estuary on oyster antioxidant and detoxification systems. The responses of various biochemical biomarkers in the ecologically important oyster Crassostrea hongkongensis collected from 7 sites in the Pearl River Estuary were quantified. Significant correlations were demonstrated between the accumulation of Cu and Zn and oxidative stress (lipid peroxidation) and oxidative stress defenses (catalase, glutathione peroxidase) in the oyster gills. Significant correlations between the accumulation of Cd and Cu and detoxification (glutathione and glutathione transferase) in the gills were also documented. Interestingly, metallothionein concentrations were positively correlated with Cd, but negatively correlated with Cu, Ni, and Zn concentrations in the gills. These measurements indicated that Cu in the Pearl River Estuary induced various biochemical responses in the oysters and influenced the susceptibility of oysters to environmental stress. The present study has provided the first evidence of antioxidant and detoxification responses in native contaminated oysters from a field environment seriously contaminated by metals. Coupling biomarkers with tissue metal concentration measurements was a promising approach to identify the metals causing biological impacts in a multimetal-contaminated estuary. Environ Toxicol Chem 2016;35:2798-2805. © 2016 SETAC. © 2016 SETAC.

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. © 2016 The Author(s).

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

PubMed

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

2016-12-01

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.

Varying Success of Relaying To Reduce Vibrio parahaemolyticus Levels in Oysters ( Crassostrea virginica).

PubMed

Taylor, Michael A; Yu, Jong W; Howell, Thomas L; Jones, Stephen H

2018-04-01

Vibrio parahaemolyticus is the leading cause of seafood-borne human infections in the United States, and many of these illnesses are associated with consumption of raw molluscan shellfish. V. parahaemolyticus levels in shellfish vary temporally and spatially with environmental conditions in and around production areas. The objective of this study was to study the potential for reducing levels of V. parahaemolyticus in live oysters by relaying them during higher-risk warm weather to a site with elevated salinity and consistently low V. parahaemolyticus levels. The effectiveness of relaying was assessed by analyzing oyster samples collected on days 0, 2, 7, 10, and 14 for V. parahaemolyticus levels using a three-tube most-probable-number enrichment method in conjunction with genetic marker-based quantitative PCR. The salinity at the relay site was always higher than the salinity at the harvest site, with the difference between the two sites ranging from 3.4 to 19.1 ppt (average, 12 ppt) during 2011 to 2014. Oysters relayed during June, July, and August in 2011 and 2012 showed consistently reduced V. parahaemolyticus levels after 14 days, whereas relaying was less successful and V. parahaemolyticus populations changed to include trh-positive strains during 2013. When effective, relay required at least 10 days to reduce V. parahaemolyticus levels. A sample of oysters collected in August 2012, which was temperature abused to increase initial V. parahaemolyticus levels, showed a 4.5-log decrease in V. parahaemolyticus levels after 14 days of relay. These results suggest that relaying oysters to reduce V. parahaemolyticus levels holds promise, but that both microbial community and environmental conditions at relay sites can affect relay success. Further investigation to discover key factors that affect V. parahaemolyticus levels in relayed oysters may aid in developing a consistent approach for reducing V. parahaemolyticus in oysters to eliminate the risk of illness for

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. Copyright © 2014 Elsevier Inc. All rights reserved.

Population resequencing reveals candidate genes associated with salinity adaptation of the Pacific oyster Crassostrea gigas.

PubMed

She, Zhicai; Li, Li; Meng, Jie; Jia, Zhen; Que, Huayong; Zhang, Guofan

2018-06-06

The Pacific oyster Crassostrea gigas is an important cultivated shellfish. As a euryhaline species, it has evolved adaptive mechanisms responding to the complex and changeable intertidal environment that it inhabits. To investigate the genetic basis of this salinity adaptation mechanism, we conducted a genome-wide association study using phenotypically differentiated populations (hyposalinity and hypersalinity adaptation populations, and control population), and confirmed our results using an independent population, high-resolution melting, and mRNA expression analysis. For the hyposalinity adaptation, we determined 24 genes, including Cg_CLCN7 (chloride channel protein 7) and Cg_AP1 (apoptosis 1 inhibitor), involved in the ion/water channel and transporter mechanisms, free amino acid and reactive oxygen species metabolism, immune responses, and chemical defence. Three SNPs located on these two genes were significantly differentiated between groups, as was Cg_CLCN7. For the hypersalinity adaptation, the biological process for positive regulating the developmental process was enriched. Enriched gene functions were focused on transcriptional regulation, signal transduction, and cell growth and differentiation, including calmodulin (Cg_CaM) and ficolin-2 (Cg_FCN2). These genes and polymorphisms possibly play an important role in oyster hyposalinity and hypersalinity adaptation. They not only further our understanding of salinity adaptation mechanisms but also provide markers for highly adaptable oyster strains suitable for breeding.

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.

Metabolism of the Pacific oyster, Crassostrea gigas, is influenced by salinity and modulates survival to the Ostreid herpesvirus OsHV-1

PubMed Central

Delisle, Lizenn; Petton, Bruno; Corporeau, Charlotte; Pernet, Fabrice

2018-01-01

ABSTRACT The Pacific oyster, Crassostrea gigas, is an osmoconforming bivalve exposed to wide salinity fluctuations. The physiological mechanisms used by oysters to cope with salinity stress are energy demanding and may impair other processes, such as defense against pathogens. This oyster species has been experiencing recurrent mortality events caused by the Ostreid herpesvirus 1 (OsHV-1). The objectives of this study were to investigate the effect of salinity (10, 15, 25 and 35‰) on energetic reserves, key enzyme activities and membrane fatty acids, and to identify the metabolic risk factors related to OsHV-1-induced mortality of oysters. Acclimation to low salinity led to increased water content, protein level, and energetic reserves (carbohydrates and triglycerides) of oysters. The latter was consistent with lower activity of hexokinase, the first enzyme involved in glycolysis, up-regulation of AMP-activated protein kinase, a major regulator of cellular energy metabolism, and lower activity of catalase, an antioxidant enzyme involved in management of reactive oxygen species. Acclimation to salinity also involved a major remodeling of membrane fatty acids. Particularly, 20:4n-6 decreased linearly with decreasing salinity, likely reflecting its mobilization for prostaglandin synthesis in oysters. The survival of oysters exposed to OsHV-1 varied from 43% to 96% according to salinity (Fuhrmann et al., 2016). Risk analyses showed that activity of superoxide dismutase and levels of proteins, carbohydrates, and triglycerides were associated with a reduced risk of death. Therefore, animals with a higher antioxidant activity and a better physiological condition seemed less susceptible to OsHV-1. PMID:29463513

Rice straw addition as sawdust substitution in oyster mushroom (Pleurotus ostreatus) planted media

NASA Astrophysics Data System (ADS)

Utami, Christine Pamardining; Susilawati, Puspita Ratna

2017-08-01

Oyster mushroom is favorite by the people because of the high nutrients. The oyster mushroom cultivation usually using sawdust. The availability of sawdust become difficult to find. It makes difficulties of mushroom cultivation. Rice straw as an agricultural waste can be used as planted media of oyster mushroom because they contain much nutrition needed to the mushroom growth. The aims of this research were to analysis the influence of rice straw addition in a baglog as planted media and to analysis the concentration of rice straw addition which can substitute sawdust in planted media of oyster mushroom. This research used 4 treatment of sawdust and rice straw ratio K = 75 % : 0 %, P1 = 60 % : 15 %, P2 = 40 % : 35 %, P3 = 15 % : 60 %. The same material composition of all baglog was bran 20%, chalk 5%, and water 70%. The parameters used in this research were wet weight, dry weight, moisture content and number of the mushroom fruit body. Data analysis was used ANOVA test with 1 factorial. The results of this research based on statistical analysis showed that there was no influence of rice straw addition in a planted media on the oyster mushroomgrowth. 15% : 60% was the concentrationof rice straw additionwhich can substitute the sawdust in planted media of oyster mushroom.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of 2003 state regulation on raw oyster-associated Vibrio vulnificus illnesses and deaths, California, USA.

PubMed

Vugia, Duc J; Tabnak, Farzaneh; Newton, Anna E; Hernandez, Michael; Griffin, Patricia M

2013-08-01

US vibriosis rates have increased since 1996, and many Vibrio vulnificus infections are fatal. In April 2003, California implemented a regulation restricting the sale of raw oysters harvested from the Gulf of Mexico during April 1-October 31, unless they were processed to reduce V. vulnificus to nondetectable levels. We analyzed California cases of V. vulnificus infection before and after the regulation's implementation and compared case data with data from other states. The annual number of reported V. vulnificus infections and deaths in California with patient's sole exposure to raw oysters dropped from 0 to 6 cases and 0 to 5 deaths per year during 1991-2002, before implementation, to 0 during 2003-2010, after implementation (p = 0.0005 for both). In other states, median annual numbers of similar cases and deaths increased slightly after 2002. The data strongly suggest that the 2003 regulation led to a significant reduction in reported raw oyster-associated V. vulnificus illnesses and deaths.

Image analysis method to quantify the effect of different treatments on the visual meat/shell ratio of half-shelled green lipped mussels (Perna canaliculus).

PubMed

Kim, Min Geun; Alçiçek, Zayde; Balaban, Murat O; Atar, Hasan Huseyin

2014-04-01

Aquacultured green lipped mussel (Perna canaliculus) is the New Zealand export leader of seafood in terms of weight. Different treatments shrink mussel meat differently and affect the consumer perception of half-shelled mussels. In order to quantify this, digital images of half-shelled green lipped mussels subjected to two postharvest treatments (ultrahigh pressure (UHP) and heat treatment (HT)) and raw controls were taken. The ratio of the view area of the meat to that of the shell (labelled as 'visual condition index' (VCI)) was measured using image analysis. A polygonal region of interest was defined on the image to depict the boundary of the meat and to calculate the view area. Raw mussels had a VCI of 85%. HT mussels had a much reduced VCI of 41%, indicating shrinkage of the meat due to heat. UHP treatment used as a shucking method resulted in a VCI of 83%. Since VCI is one measure of quality for the consumer, this quantitative method can be used in the optimization of shucking treatment (HT or UHP). VCI can be used to optimize postharvest treatments to minimize meat shrinkage. This method can also be applied to other shellfish such as oysters and clams. © 2013 Society of Chemical Industry.

Nutrient Removal through Oyster Habitat Restoration in the Indian River Lagoon, Florida

NASA Astrophysics Data System (ADS)

Gallagher, S. M.; Schmidt, C. A.; Walters, L.; Blank, R.

2017-12-01

In 2016, an algae bloom in the Indian River Lagoon (IRL) caused a state of emergency in Florida. As with many estuaries, nutrient loading in the IRL has led to periodic eutrophication. While previous studies have shown oyster bed restoration reduces suspended organic matter in estuaries, similar reductions to net nutrient loads are not well established. In addition, previous studies have focused on seasonal variation rather than ongoing yearly effects. Here, we determine the net nitrogen and phosphorus effects of oyster restoration in the IRL over seven years. Analysis of aerial images from 1943 and 2009 showed 14.7 ha of oyster beds were destroyed by boat traffic in the IRL (40% loss). According to our measurements of restored oyster bed sediment, this equates to a maximum of 1,580,000 kg•N•yr-1 of lost denitrification potential; this is equivalent to 150% of estimated current nitrogen loading in the IRL. Oyster restoration began in the IRL in 2007 and has recovered 7.7% of the lost beds and denitrification potential (1.13 ha and 107,000 kg•N•yr-1•ha-1). In all cases, denitrification reached a maximum within two years and remained significantly higher than open sediment for at least the seven years observed. Denitrification benefits came at the cost of mobilizing a maximum of 3450 kg ha-1 of recalcitrant phosphorus from restored bed sediment. This effect was limited to the two years following restoration, whereas increased denitrification was ongoing. Overall, our results show oyster restoration achieved maximum denitrification within two years and maintained significant denitrification benefits for at least seven years. In addition, our results are useful for future oyster restoration projects since they quantify nitrogen benefits in terms of phosphorus mobilization.

The comprehensive immunomodulation of NeurimmiRs in haemocytes of oyster Crassostrea gigas after acetylcholine and norepinephrine stimulation.

PubMed

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

2015-11-14

Neural-endocrine-immune (NEI) system is a major modulation network among the nervous, endocrine and immune system and weights greatly in maintaining homeostasis of organisms during stress and infection. Some microRNAs are found interacting with NEI system (designated NeurimmiRs), addressing swift modulations on immune system. The oyster Crassostrea gigas, as an intertidal bivalve, has evolved a primary NEI system. However, the knowledge about NeurimmiRs in oysters remains largely unknown. Six small RNA libraries from haemocytes of oysters stimulated with acetylcholine (ACh) and norepinephrine (NE) were sequenced to identify neurotransmitter-responsive miRNAs and survey their immunomodulation roles. A total of 331 miRNAs (132 identified in the present study plus 199 identified previously) were subjected to expression analysis, and twenty-one and sixteen of them were found ACh- or NE-responsive, respectively (FDR < 0.05). Meanwhile, 21 miRNAs exhibited different expression pattern after ACh or NE stimulation. Consequently, 355 genes were predicted as putative targets of these neurotransmitter-responsive miRNAs in oyster. Through gene onthology analysis, multiple genes involved in death, immune system process and response to stimulus were annotated to be modulated by NeurimmiRs. Besides, a significant decrease in haemocyte phagocytosis and late-apoptosis or necrosis rate was observed after ACh and NE stimulation (p < 0.05) while early-apoptosis rate remained unchanged. A comprehensive immune-related network involving PRRs, intracellular receptors, signaling transducers and immune effectors was proposed to be modulated by ACh- and NE-responsive NeurimmiRs, which would be indispensable for oyster haemocytes to respond against stress and infection. Characterization of the NeurimmiRs would be an essential step to understand the NEI system of invertebrate and the adaptation mechanism of oyster.

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.

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 log 10 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. © 2016 Institute of Food Technologists®.

Preliminary investigations on a new method of retaining the colour of shucked cockles ( Anadara Granosa), and the extension of shelflife by gamma irradiation and vacuum packing

NASA Astrophysics Data System (ADS)

Ng, Cher Siang; Low, Lai Kim; Chia, Lawrence H. L.

Live cockles were incubated in atmospheres containing different concentrations of carbon monoxide. Since CO combines more readily with myoglobin and haemoglobin than oxygen, the formation of in vivo deoxygenated haemoglobins and post mortem formation of methaemoglobin were retarded by the more stable carboxyhaemoglobin (HbCO). The bright red colour of the stable HbCO is retained during storage, giving the desired colour to the cockles. The colour of normal, chilled cockle meat deteriorated after 3 days ice storage while those treated with 50 and 100% CO retained the bright deep orange colour up to 10 days storage. Irradiation caused faster colour deterioration in both CO and non-CO treated samples. Vacuum packing influenced the colour of the cockles with irradiation and with CO treatments. In non-CO treated, irradiated samples, the effect of vacuum packing was not obvious. In CO treated, irradiated samples, vacuum packing retarded the deterioration of colour. Odour developments were influenced by irradiation, vacuum packing and storage temperature, and were not influenced by CO treatments. Irradiation suppressed the development of odour for the first 11 days storage (0°C) while vacuum packing depressed the odour by lowering its intensity instead. Odour development was slowed down by lowering the storage temperature. The odour of shucked cockles was rejected within one day at room temperature (26-28°C) while at 0°C the odour of the shucked cockles was still acceptable after 10 days. Suitable chemical indices for quality are K value and TVBN. Treatment with CO did not influence the K value development. Vacuum packing produced the highest K values after 19 days storage (0°C), while irradiated samples had higher K values than non-irradiated samples. The TVBN increased with storage and is an indicator of the odour development. The use of CO treatment extended the shelflife of the cockles based on appearance. A combination of CO treatment, vacuum packing, ice storage

Multidimensional assessment of sustainability extractivism of mangrove oyster Crassostrea spp. in the estuary of Cananéia, São Paulo, Brazil.

PubMed

Machado, I C; Fagundes, L; Henriques, M B

2015-08-01

This study was carried out with groups of extractivists of mangrove oysters in the estuary of Cananéia, São Paulo State, Brazil, between the years 1999 and 2007 with the objective to evaluate and compare trends in the sustainability of this activity, in a multidimensional and integrated way, in social, economic, ecological, technological and ethical dimensions, using the method RAPFISH. The different groups had distinct trends related to sustainability and the social, technological and ethical dimensions had more influence on trends in sustainability than the ecological and economic dimensions. The group with the best performance in the sustainability assessment was Mandira, due to advances promoted by local social organization. On the other hand, the Porto Cubatão group showed the worst performance, once this is very recent group in the extractivism of oysters. The RAPFISH proved to be a useful tool for data assessment.

Use of OmpU porins for attachment and invasion of Crassostrea gigas immune cells by the oyster pathogen Vibrio splendidus

PubMed Central

Duperthuy, Marylise; Schmitt, Paulina; Garzón, Edwin; Caro, Audrey; Rosa, Rafael D.; Le Roux, Frédérique; Lautrédou-Audouy, Nicole; Got, Patrice; Romestand, Bernard; de Lorgeril, Julien; Kieffer-Jaquinod, Sylvie; Bachère, Evelyne; Destoumieux-Garzón, Delphine

2011-01-01

OmpU porins are increasingly recognized as key determinants of pathogenic host Vibrio interactions. Although mechanisms remain incompletely understood, various species, including the human pathogen Vibrio cholera, require OmpU for host colonization and virulence. We have shown previously that OmpU is essential for virulence in the oyster pathogen Vibrio splendidus LGP32. Here, we showed that V. splendidus LGP32 invades the oyster immune cells, the hemocytes, through subversion of host-cell actin cytoskeleton. In this process, OmpU serves as an adhesin/invasin required for β-integrin recognition and host cell invasion. Furthermore, the major protein of oyster plasma, the extracellular superoxide dismutase Cg-EcSOD, is used as an opsonin mediating the OmpU-promoted phagocytosis through its RGD sequence. Finally, the endocytosed bacteria were found to survive intracellularly, evading the host defense by preventing acidic vacuole formation and limiting reactive oxygen species production. We conclude that (i) V. splendidus is a facultative intracellular pathogen that manipulates host defense mechanisms to enter and survive in host immune cells, and (ii) that OmpU is a major determinant of host cell invasion in Vibrio species, used by V. splendidus LGP32 to attach and invade oyster hemocytes through opsonisation by the oyster plasma Cg-EcSOD. PMID:21282662

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

USDA-ARS?s Scientific Manuscript database

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...

Molecular characterization and analysis of a putative 5-HT receptor involved in reproduction process of the pearl oyster Pinctada fucata.

PubMed

Wang, Qi; He, Maoxian

2014-08-01

5-HT (5-hydroxytryptamine; serotonin) has been linked to a variety of biological roles including gonad maturation and sequential spawning in bivalve molluscs. To gain a better understanding of the effects of 5-HT on developmental regulation in the pearl oyster Pinctada fucata, the isolation, cloning, and expression of the 5-HT receptor was investigated in this study. A full-length cDNA (2541 bp) encoding a putative 5-HT receptor (5-HTpf) of 471 amino acids was isolated from the ovary of the pearl oyster. It shared 71% and 51% homology, respectively, with the Crassostrea gigas 5-HT receptor and the Aplysia californica 5-HT1ap. The 5-HTpf sequence possessed the typical characteristics of seven transmembrane domains and a long third inner loop. Phylogenetic analysis also indicated that 5-HTpf was classified into the 5-HT1 subtype together with other invertebrate 5-HT1 receptors. Quantitative RT-PCR showed that 5-HTpf is widely expressed in all tissues tested, is involved in the gametogenesis cycle, embryonic and larval development stages, and expression is induced by E2 in ovarian tissues. These results suggest that 5-HTpf is involved in the reproductive process, specifically in the induction of oocyte maturation and spawning of P. fucata. Copyright © 2014 Elsevier Inc. All rights reserved.

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...

An outbreak of norovirus infection associated with fermented oyster consumption in South Korea, 2013.

PubMed

Cho, H G; Lee, S G; Lee, M Y; Hur, E S; Lee, J S; Park, P H; Park, Y B; Yoon, M H; Paik, S Y

2016-10-01

An acute gastroenteritis (AGE) outbreak was reported in May 2013 in Gyeonggi Province, South Korea. Eight students who had eaten breakfast on 21 May 2013 at a high-school restaurant exhibited AGE symptoms. Our case-control study showed that a strong association was observed between AGE symptoms and fermented oyster consumption. Virological studies also indicated that noroviruses (NoVs) were detected from both clinical samples and fermented oyster samples, and multiple different genotypes (genogroups GII.4, GII.11 and GII.14) of NoVs were present in both samples. The nucleotide sequence similarity between the strains found in the clinical samples and those in the fermented oysters was more than 99·5%. Therefore, to prevent further outbreaks, proper management of raw oysters is necessary and the food industry should be aware of the risk of viral gastroenteritis posed by fermented oysters contaminated with NoVs.

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.

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

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

Effects of electrolyzed oxidizing water treatment on reducing Vibrio parahaemolyticus and Vibrio vulnificus in raw oysters.

PubMed

Ren, Tingting; Su, Yi-Cheng

2006-08-01

Contamination of Vibrio parahaemolyticus and Vibrio vulnificus in oysters is a food safety concern. This study investigated effects of electrolyzed oxidizing (EO) water treatment on reducing V. parahaemolyticus and V. vulnificus in laboratory-contaminated oysters. EO water exhibited strong antibacterial activity against V. parahaemolyticus and V. vulnificus in pure cultures. Populations of V. parahaemolyticus (8.74 x 10(7) CFU/ml) and V. vulnificus (8.69 x 10(7) CFU/ml) decreased quickly in EO water containing 0.5% NaCl to nondetectable levels (> 6.6 log reductions) within 15 s. Freshly harvested Pacific oysters were inoculated with a five-strain cocktail of V. parahaemolyticus or V. vulnificus at levels of 10(4) and 10(6) most probable number (MPN)/g and treated with EO water (chlorine, 30 ppm; pH 2.82; oxidation-reduction potential, 1131 mV) containing 1% NaCl at room temperature. Reductions of V. parahaemolyticus and V. vulnificus in oysters were determined at 0 (before treatment), 2, 4, 6, and 8 h of treatment. Holding oysters inoculated with V. parahaemolyticus or V. vulnificus in the EO water containing 1% NaCl for 4 to 6 h resulted in significant (P < 0.05) reductions of V. parahaemolyticus and V. vulnificus by 1.13 and 1.05 log MPN/g, respectively. Extended exposure (> 12 h) of oysters in EO water containing high levels of chlorine (> 30 ppm) was found to be detrimental to oysters. EO water could be used as a postharvest treatment to reduce Vibrio contamination in oysters. However, treatment should be limited to 4 to 6 h to avoid death of oysters. Further studies are needed to determine effects of EO water treatment on sensory characteristics of oysters.

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.

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

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.

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

...; 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 the Technical Specifications to...

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

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

Follow-Up of Norovirus Contamination in an Oyster Production Area Linked to Repeated Outbreaks.

PubMed

Le Mennec, Cécile; Parnaudeau, Sylvain; Rumebe, Myriam; Le Saux, Jean-Claude; Piquet, Jean-Côme; Le Guyader, S Françoise

2017-03-01

A production area repeatedly implicated in oyster-related gastroenteritis in France was studied for several months over 2 years. Outbreaks and field samples were analyzed by undertaking triplicate extractions, followed by norovirus (NoV) detection using triplicate wells for genomic amplification. This approach allowed us to demonstrate that some variabilities can be observed for samples with a low level of contamination, but most samples analyzed gave reproducible results. At the first outbreak, implicated oysters were collected at the beginning of the contamination event, which was reflected by the higher NoV levels during the first month of the study. During the second year, NoV concentrations in samples implicated in outbreaks and collected from the production area were similar, confirming the failure of the shellfish depuration process. Contamination was detected mainly during winter-spring months, and a high prevalence of NoV GI contamination was observed. A half-life of 18 days was calculated from NoV concentrations detected in oysters during this study, showing a very slow decrease of the contamination in the production area. Preventing the contamination of coastal waters should be a priority.

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.

Cholera after the consumption of raw oysters. A case report.

PubMed

Klontz, K C; Tauxe, R V; Cook, W L; Riley, W H; Wachsmuth, I K

1987-12-01

In August 1986, a 76-year-old woman in Miami, Florida, developed profuse watery diarrhea and abdominal cramps. Two and four days before the onset of her illness, she had eaten six raw oysters at each of two restaurants in Miami. A stool specimen yielded toxigenic Vibrio cholerae O1 biotype El Tor, serotype Inaba. The results of toxin gene probing of the organism recovered from the patient differed significantly from those of other V. cholerae O1 isolates from the Gulf Coast and elsewhere in the world. A program of active surveillance identified no other cases of cholera in Miami. The source of the raw oysters eaten by the patient was traced to Louisiana. Her case represents the first reported case of cholera associated with eating raw oysters.

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.

Oyster reef restoration in controlling coastal pollution around India: A viewpoint.

PubMed

Chakraborty, Parthasarathi

2017-02-15

Coastal waters receive large amounts of nutrients and pollutants from different point and nonpoint sources through bays and estuaries. Excess supply of nutrients in coastal waters may have detrimental effects, leading to hypoxia and anoxia from eutrophication. Reduction in concentrations of excess nutrients/pollutants in bays/estuarine system is must for healthy coastal ecosystem functioning. Conservations of bays, estuaries and coastal zones are must for sustainable development in any maritime country. Excellent ability of oyster in removing and controlling the concentrations of nutrients, pollutants, suspended particulate matters from bays and estuarine waters stimulated me to provide a viewpoint on oyster reef restoration in controlling nutrient/heavy metals fluxes and marine coastal pollution around India. Oyster reefs restoration may decrease nutrient and heavy metals fluxes in coastal waters and reduce the intensity of oxygen depletion in the coastal Arabian Sea (seasonal) and Bay of Bengal. However, extensive research is recommended to understand the impact of oyster reef restoration in controlling coastal pollution which is essential for sustainable development around India. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

USDA-ARS?s Scientific Manuscript database

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...

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

Measuring Macrobenthos Biodiversity at Oyster Aquaculture Sites in the Delaware Inland Bays

NASA Astrophysics Data System (ADS)

Fuoco, M. J.; Ozbay, G.

2016-12-01

The Delaware Inland Bays consists of three shallow coastal bays located in the southern portion of Delaware. Anthropogenic activities have led to the degradation of water quality, because the bays are surrounded by highly developed areas and have low flushing rates. This results in loss of biodiversity and abundance of organisms. Ongoing degradation of the bays has led to a dramatic decline in local oyster populations since the late 1800s. Oysters are keystone species, which provide habitats for organisms and help to improve water quality. This study aims to find if the introduction of oyster aquaculture improves local biodiversity and abundance of macrobenthos. The study was conducted in Rehoboth Bay, Indian River Bay and Little Assawoman Bay. Aquaculture gear was placed at one location in each of the bays and 24 sediment core samples were taken once a month. From these core samples all worms were fixed and stained in a 10% Formalin Rose Bengal solution and preserved in 70% Ethanol for later identification. Stable carbon and nitrogen isotope analysis of oyster tissue will also be performed to assess the health of the bay. The goals of this research are to better understand the role of oyster aquaculture in restoring the viability and health of the Delaware Inland Bays.

Development of genetic programming-based model for predicting oyster norovirus outbreak risks.

PubMed

Chenar, Shima Shamkhali; Deng, Zhiqiang

2018-01-01

Oyster norovirus outbreaks pose increasing risks to human health and seafood industry worldwide but exact causes of the outbreaks are rarely identified, making it highly unlikely to reduce the risks. This paper presents a genetic programming (GP) based approach to identifying the primary cause of oyster norovirus outbreaks and predicting oyster norovirus outbreaks in order to reduce the risks. In terms of the primary cause, it was found that oyster norovirus outbreaks were controlled by cumulative effects of antecedent environmental conditions characterized by low solar radiation, low water temperature, low gage height (the height of water above a gage datum), low salinity, heavy rainfall, and strong offshore wind. The six environmental variables were determined by using Random Forest (RF) and Binary Logistic Regression (BLR) methods within the framework of the GP approach. In terms of predicting norovirus outbreaks, a risk-based GP model was developed using the six environmental variables and various combinations of the variables with different time lags. The results of local and global sensitivity analyses showed that gage height, temperature, and solar radiation were by far the three most important environmental predictors for oyster norovirus outbreaks, though other variables were also important. Specifically, very low temperature and gage height significantly increased the risk of norovirus outbreaks while high solar radiation markedly reduced the risk, suggesting that low temperature and gage height were associated with the norovirus source while solar radiation was the primary sink of norovirus. The GP model was utilized to hindcast daily risks of oyster norovirus outbreaks along the Northern Gulf of Mexico coast. The daily hindcasting results indicated that the GP model was capable of hindcasting all historical oyster norovirus outbreaks from January 2002 to June 2014 in the Gulf of Mexico with only two false positive outbreaks for the 12.5-year period. The

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. © 2015 John Wiley & Sons Ltd.

Effect of linear alkylbenzene mixtures and sanitary sewage in biochemical and molecular responses in pacific oyster Crassostrea gigas.

PubMed

Flores-Nunes, Fabrício; Mattos, Jacó J; Zacchi, Flávia L; Serrano, Miguel A S; Piazza, Clei E; Sasaki, Silvio T; Taniguchi, Satie; Bicego, Márcia C; Melo, Cláudio M R; Bainy, Afonso C D

2015-11-01

Urban effluents are rich in nutrients, organic matter, pharmaceuticals and personal care products (PPCPs), pesticides, hydrocarbons, surfactants, and others. Previous studies have shown that oysters Crassostrea gigas accumulate significant levels of linear alkylbenzenes (LABs) in sanitary sewage contaminated sites, but there is little information about its toxicological effects in marine bivalves. The aim of this study was to analyze the transcription of genes in two tissues of C. gigas exposed for 12, 24, and 36 h to LABs or sanitary sewage. Likewise, the activity of antioxidant and biotransformation enzymes was measured in oysters exposed for 36 h in all groups. Oysters exposed to LABs and oysters exposed to sanitary sewage showed different patterns of transcriptional responses. LAB-exposed oysters showed lower level of biological responses than the oysters exposed to sanitary sewage. Despite the ability of the oyster C. gigas to accumulate LABs (28-fold), the data indicate that these contaminants are not the cause for the transcriptional responses observed in oysters exposed to sanitary sewage. Possibly, the biological changes observed in the sanitary sewage-exposed oysters are associated with the presence of other contaminants, which might have caused synergistic, additive, or antagonistic effects. The results show that FABP-like and GST-ω-like messenger RNAs (mRNAs) have a rapid response in tissues of oyster C. gigas exposed to sanitary sewage, suggesting a possible protective response and a role in maintaining homeostasis of these organisms.

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.

The effect of a novel photodynamic activation method mediated by curcumin on oyster shelf life and quality.

PubMed

Liu, Fang; Li, Zhaojie; Cao, Binbin; Wu, Juan; Wang, Yuming; Xue, Yong; Xu, Jie; Xue, Changhu; Tang, Qing Juan

2016-09-01

In this paper, the effect of photodynamic method mediated by curcumin (PDT) on the shelf life and quality of pacific oysters during storage at 5±1°C were analyzed. In our previous study we investigated the optimal treatment conditions of photodynamic method mediated by curcumin to sterilization were 10uM photosensitizer concentration and 5.4J/cm 2 light energy density. Under these conditions, the effect of a novel photodynamic activation method mediated by curcumin on oyster shelf life and quality was researched. The total bacterial counts, TVB-N content and sensory analysis were used to evaluate the effects on oyster shelf life. The oyster shelf life was prolonged from 8days to 12days after photodynamic treatment and the oysters in the treatment group displayed notable odor retention, produced fewer odor corrupting substances when the control group oysters reached the end of their shelf life (day 8). Texture, free amino acid contents and fatty acid levels were applied to estimate the quality of the treated oysters. The texture had no significant change after treated with PDT. At the end of oyster shelf life, compared PDT group (PDT) with control group (control), total free amino acid contents (control: 234.30mg/100g, PDT: 813.02mg/100g) was higher and free fatty acid levels (control: 0.071mEq/L, PDT: 0.0455mEq/L) displayed lower in PDT group. This indicated that the treated oysters oxidized minimally, decayed slowly, decomposed fewer nutrients and had lower metabolic levels of spoilage microorganisms. PDT has a positive effect on prolonging oyster shelf life and its quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

Histological Alterations in Pacific Oysters Crassostrea gigas that Survived a Summer Mortality Event in Baja California, Mexico.

PubMed

Cáceres-Martínez, Jorge; Vásquez-Yeomans, Rebeca; Danigo, Philippe; Reyes-Roel, Carlos

2018-03-01

A mortality episode (>90%) of triploid and diploid Pacific oysters Crassostrea gigas cultured in Baja California Sur occurred during summer 2012, coinciding with a thermal anomaly, an algal bloom, and low oxygen values. To help explain the cause of the mortalities, histological analyses and molecular tests for specific pathogens (ostreid herpesvirus 1 [OsHV-1] and Perkinsus marinus) were performed on oysters surviving at the end of the episode. Triploid oysters showed a high percentage of males (43%) and hermaphrodites (30%); 93% of these oysters were in the gonadic reabsorption stage, and in some cases, hemocytes completely filled the lumen of the gonadic follicles. Oysters presented large areas with severe hemocyte infiltration that extended toward the digestive gland. Diploid oysters showed similar gonad alterations. None of samples showed histological or molecular evidence of OsHV-1 or P. marinus. Histological alterations can be related to physiological disorders caused by the mechanism driving summer mortality. This is the first case history of a summer mortality episode among Pacific oysters in Mexico. © 2017 American Fisheries Society.

Molecular Epidemiology of Oyster-Related Human Noroviruses and Their Global Genetic Diversity and Temporal-Geographical Distribution from 1983 to 2014

PubMed Central

Yu, Yongxin; Cai, Hui; Hu, Linghao; Lei, Rongwei; Pan, Yingjie; Yan, Shuling

2015-01-01

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. PMID:26319869

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. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Effective preservation techniques to prolong the shelf life of ready-to-eat oysters.

PubMed

Costa, Cristina; Conte, Amalia; Del Nobile, Matteo Alessandro

2014-10-01

Oysters have a high commercial value but owing to their short shelf life are generally commercialized as raw material within very restricted market borders. A step-by-step optimization approach was used in this work to design ready-to-eat oyster packaging. In particular, six different steps were carried out in order to extend their shelf life. The concentration of sodium alginate to realize a coating that was effective in terms of easy peeling and ability in preventing product dehydration was optimized. Coated oysters were packaged under different modified atmosphere (MAP) conditions to find the best MAP. Subsequently, to further promote product preservation, sodium acetate was selected as an effective antimicrobial agent to be applied by dipping treatment prior to coating. All preservation strategies singly tested were finally combined to assess the shelf life prolongation of ready-to-eat oysters. Dipping in sodium acetate (10 g L⁻¹), coating with sodium alginate (40 g L⁻¹) and packaging under MAP (0:75 O₂:CO₂) represent the best conditions to guarantee a significant shelf life extension to about 160 h compared with 57 h for unpackaged oysters. © 2014 Society of Chemical Industry.

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.

The modulation role of serotonin in Pacific oyster Crassostrea gigas in response to air exposure.

PubMed

Dong, Wenjing; Liu, Zhaoqun; Qiu, Limei; Wang, Weilin; Song, Xiaorui; Wang, Xiudan; Li, Yiqun; Xin, Lusheng; Wang, Lingling; Song, Linsheng

2017-03-01

Serotonin, also known as 5-hydroxytryptamine (5-HT), is a critical neurotransmitter in the neuroendocrine-immune regulatory network and involved in regulation of the stress response in vertebrates and invertebrates. In the present study, serotonin was found to be widely distributed in the tissues of Pacific oyster Crassostrea gigas, including haemolymph, gonad, visceral ganglion, mantle, gill, labial palps and hepatopancreas, and its concentration increased significantly in haemolymph and mantle after the oysters were exposed to air for 1 d. The apoptosis rate of haemocytes was significantly declined after the oysters received an injection of extra serotonin, while the activity of superoxide dismutase (SOD) in haemolymph increased significantly. After the stimulation of serotonin during air exposure, the apoptosis rate of oyster haemocytes and the concentration of H 2 O 2 in haemolymph were significantly decreased, while the SOD activity was significantly elevated. Furthermore, the survival rate of oysters from 4 th to 6 th d after injection of serotonin was higher than that of FSSW group and air exposure group. The results clearly indicated that serotonin could modulate apoptotic effect and redox during air exposure to protect oysters from stress. Copyright © 2017 Elsevier Ltd. All rights reserved.

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…

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, oyster...

Assessment of health status of oysters (Crassostreagigas) exposed to environmentally relevant concentrations of Ag and Cu in brackish waters

NASA Astrophysics Data System (ADS)

Rementeria, Ane; Mikolaczyk, Mathilde; Peña, Ainhize; Lanceleur, Laurent; Blanc, Gérard; Soto, Manu; Schäfer, Jörg; Zaldibar, Beñat

2017-12-01

Human activities have altered estuarine environments leading to increased presence of different pollutants including metals. Although the implementation of new environmental policies has caused a considerable decrease in trace metal concentrations in estuaries around the Bay of Biscay, some elements such as copper (Cu) and silver (Ag) are still present in relatively high concentrations. Oysters have been widely used in environmental biomonitoring programs as sentinel organisms. Oysters Crassostrea gigas from an uncontaminated estuary were exposed to sublethal, environmentally relevant concentrations of Cu (2000 ng Cu/L) and Ag (500 ng Ag/L) during 14 days in brackish water (S = 18). A battery of cell and tissue level (exposure) biomarkers at different levels of biological complexity was applied and integrated into the Integrative Biological Response (IBR) index including: metallothionein contents, intralysosomal metal accumulation, digestive gland atrophy and digestive gland tissue integrity. Condition Index (CI) was incorporated into the IBR index as a complementary parameter that reflects the general physiological condition of oysters (organism level). Results indicated an increase in intralysosomal metal accumulation after 7 and 14 days of exposure to Ag together with an increase in the digestive epithelium atrophy and lipofuscin content after 7 days of exposure to Ag. The responses detected with the aid of biomarkers integrated in the IBR index showed higher toxicity in oysters exposed to Ag, inducing the clear onset of detoxification processes which also occurred, to a lower extent, in Cu-exposed oysters.

Integrated application of transcriptomics and metabolomics provides insights into glycogen content regulation in the Pacific oyster Crassostrea gigas.

PubMed

Li, Busu; Song, Kai; Meng, Jie; Li, Li; Zhang, Guofan

2017-09-11

The Pacific oyster Crassostrea gigas is an important marine fishery resource, which contains high levels of glycogen that contributes to the flavor and the quality of the oyster. However, little is known about the molecular and chemical mechanisms underlying glycogen content differences in Pacific oysters. Using a homogeneous cultured Pacific oyster family, we explored these regulatory networks at the level of the metabolome and the transcriptome. Oysters with the highest and lowest natural glycogen content were selected for differential transcriptome and metabolome analysis. We identified 1888 differentially-expressed genes, seventy-five differentially-abundant metabolites, which are part of twenty-seven signaling pathways that were enriched using an integrated analysis of the interaction between the differentially-expressed genes and the differentially-abundant metabolites. Based on these results, we found that a high expression of carnitine O-palmitoyltransferase 2 (CPT2), indicative of increased fatty acid degradation, is associated with a lower glycogen content. Together, a high level of expression of phosphoenolpyruvate carboxykinase (PEPCK), and high levels of glucogenic amino acids likely underlie the increased glycogen production in high-glycogen oysters. In addition, the higher levels of the glycolytic enzymes hexokinase (HK) and pyruvate kinase (PK), as well as of the TCA cycle enzymes malate dehydrogenase (MDH) and pyruvate carboxylase (PYC), imply that there is a concomitant up-regulation of energy metabolism in high-glycogen oysters. High-glycogen oysters also appeared to have an increased ability to cope with stress, since the levels of the antioxidant glutathione peroxidase enzyme 5 (GPX5) gene were also increased. Our results suggest that amino acids and free fatty acids are closely related to glycogen content in oysters. In addition, oysters with a high glycogen content have a greater energy production capacity and a greater ability to cope with

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. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

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... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing, oyster dredging and planting, and fishing may be permitted to carry persons in addition to its crew. (b) The...

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... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing, oyster dredging and planting, and fishing may be permitted to carry persons in addition to its crew. (b) The...

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. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Differential expression of genes encoding anti-oxidant enzymes in Sydney rock oysters, Saccostrea glomerata (Gould) selected for disease resistance.

PubMed

Green, Timothy J; Dixon, Tom J; Devic, Emilie; Adlard, Robert D; Barnes, Andrew C

2009-05-01

Sydney rock oysters (Saccostrea glomerata) selectively bred for disease resistance (R) and wild-caught control oysters (W) were exposed to a field infection of disseminating neoplasia. Cumulative mortality of W oysters (31.7%) was significantly greater than R oysters (0.0%) over the 118 days of the experiment. In an attempt to understand the biochemical and molecular pathways involved in disease resistance, differentially expressed sequence tags (ESTs) between R and W S. glomerata hemocytes were identified using the PCR technique, suppression subtractive hybridisation (SSH). Sequencing of 300 clones from two SSH libraries revealed 183 distinct sequences of which 113 shared high similarity to sequences in the public databases. Putative function could be assigned to 64 of the sequences. Expression of nine ESTs homologous to genes previously shown to be involved in bivalve immunity was further studied using quantitative reverse-transcriptase PCR (qRT-PCR). The base-line expression of an extracellular superoxide dismutase (ecSOD) and a small heat shock protein (sHsP) were significantly increased, whilst peroxiredoxin 6 (Prx6) and interferon inhibiting cytokine factor (IK) were significantly decreased in R oysters. From these results it was hypothesised that R oysters would be able to generate the anti-parasitic compound, hydrogen peroxide (H(2)O(2)) faster and to higher concentrations during respiratory burst due to the differential expression of genes for the two anti-oxidant enzymes of ecSOD and Prx6. To investigate this hypothesis, protein extracts from hemolymph were analysed for oxidative burst enzyme activity. Analysis of the cell free hemolymph proteins separated by native-polyacrylamide gel electrophoresis (PAGE) failed to detect true superoxide dismutase (SOD) activity by assaying dismutation of superoxide anion in zymograms. However, the ecSOD enzyme appears to generate hydrogen peroxide, presumably via another process, which is yet to be elucidated. This

Characterisation of the spoilage bacterial microbiota in oyster gills during storage at different temperatures.

PubMed

Chen, Huibin; Liu, Zhiyu; Wang, Meiying; Chen, Shaojun; Chen, Tuanwei

2013-12-01

The spoilage bacterial community in oyster gill was investigated during storage at 4, 10 and 20 °C. Aerobic plate counts and pH values were determined. Total bacterial DNA was extracted from oyster gill and bulk cells of plate count media. The major bacterial species during fresh or different temperatures storage were determined by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The initial aerobic plate count in oyster gill reached 6.70 log CFU g(-1). PCR-DGGE fingerprinting analysis of the 16S rRNA gene V3 region revealed that most of the strains in fresh oyster gill belonged to the genera Lactococcus and Enterobacter. The major spoilage bacteria at a storage temperature of 20 °C were Leuconostoc pseudomesenteroides, an uncultured bacterium, Cytophaga fermentans, Lactococcus lactis, Pseudoalteromonas sp., Enterococcus mundtii, Clostridium difficile and an uncultured Fusobacteria; those at 10 °C were Lactococcus spp., Lactobacillus curvatus, Weissella confusa and C. difficile; those at 4 °C were Lactococcus, Weissella, Enterobacter and Aeromonas. The other minor species were L. curvatus, Pseudomonas sp. and E. mundtii. Lactococcus spp. was the most common main spoilage bacteria in oyster gill during chilled storage. PCR-DGGE revealed the complexity of the bacterial microbiota and the major bacteria species in oyster gill for fresh and storage. © 2013 Society of Chemical Industry.

Widespread survey finds no evidence of Haplosporidium nelsoni (MSX) in Gulf of Mexico oysters.

PubMed

Ford, Susan E; Paterno, Jenny; Scarpa, Emily; Stokes, Nancy A; Kim, Yungkul; Powell, Eric N; Bushek, David

2011-02-22

The advent of molecular detection assays has provided a set of very sensitive tools for the detection of pathogens in marine organisms, but it has also raised problems of how to interpret positive signals that are not accompanied by visual confirmation. PCR-positive results have recently been reported for Haplosporidium nelsoni (MSX), a pathogen of the oyster Crassostrea virginica in 31 of 40 oysters from 6 sites in the Gulf of Mexico and the Caribbean Sea. Histological confirmation of the PCR results was not undertaken, and no haplosporidian has been reported from the numerous histological studies and surveys of oysters in the region. To further investigate the possibility that H. nelsoni is present in this region, we sampled 210 oysters from 40 sites around the Gulf of Mexico and Puerto Rico using PCR and 180 of these using tissue-section histology also. None of the oysters showed evidence of H. nelsoni by PCR or of any haplosporidian by histology. We cannot, therefore, confirm that H. nelsoni is present and widespread in the Gulf of Mexico and the Caribbean Sea. Our results do not prove that H. nelsoni is absent from the region, but taken together with results from previous histological surveys, they suggest that for the purposes of controlling oyster importation, the region should continue to be considered free of the parasite.

Bioaccumulation and elimination of Cryptosporidium parvum oocysts in experimentally exposed Eastern oysters (Crassostrea virginica) held in static tank aquaria.

PubMed

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

2014-03-03

A variety of human enteropathogens, including viruses, bacteria, and parasites, have been shown to bioaccumulate in suspension-feeding bivalve shellfish. Cryptosporidium parvum is a zoonotic protozoan parasite that has been detected in many shellfish species within both fecally contaminated and clean oyster growing areas across the globe. For this study, C. parvum oocysts (1000 and 10,000) were spiked into 10 L of water in static tank systems housing Crassostrea virginica. Oysters were either held in the contaminated aquaria for 7 days of exposure or were exposed for 24h and subsequently placed in a clean static tank system for the remainder of the trial. Individual oysters, fecal material, and tank water were analyzed for oocysts up to 7 days post-exposure via direct immunofluorescence. Oysters held under chronic exposure conditions gradually accumulated oocysts (1.5 or 34.4 oocysts/oyster/day for low or high dose exposure groups, respectively) between days 1 and 7, with an exponential uptake in oocysts observed within the first 24h post-exposure (mean uptake of 29.6 or 241.9 oocysts/oyster, respectively). Oysters that were transferred to clean water after 24h were capable of slowly depurating oocysts, following a linear trend. During chronic exposure trials 48-49% of the total spiked inoculum was recovered from oyster tissue, whereas 4.8-5.9% and 38-40% was recovered from tank water and from fecal material at day 7, respectively. In acute exposure trials, 30-31% of the total tank inoculum was found in oysters, suggesting that chronically exposed oysters were likely re-filtering some oocysts. Examinations of oyster fecal material from acute exposures revealed that 72-82% of oocysts recovered were already excreted at the time of oyster transfer (day 1), with only 18-28% being excreted during the static depuration phase. These data support that although most C. parvum oocysts are removed by C. virginica oysters within 24h, elimination after this point occurs slowly

Long-term spatiotemporal trends and health risk assessment of oyster arsenic levels in coastal waters of northern South China Sea.

PubMed

Wang, Xuefeng; Wang, Lifei; Jia, Xiaoping; Jackson, Donald A

2017-09-01

Long-term spatiotemporal trends and health risk assessment of oyster arsenic levels in the coastal waters of northern South China Sea were investigated in order to help improve the quality and safety control and sustainable aquaculture for mollusks in China. Cultured oysters (Crassostrea rivularis) collected from the waters of 23 bays, harbors, and estuaries along the coast of northern South China Sea from 1989 to 2012 were examined for spatial patterns and long-term temporal trends of oyster arsenic levels. Single-factor index and health risk assessment were used to quantify arsenic exposure to human health through oyster consumption. Overall, arsenic was detected in 97.4% of the oyster samples, and oyster arsenic levels were non-detectable-2.51 mg/kg with an average of 0.63 ± 0.54 mg/kg. Oyster arsenic levels in the coastal waters of northern South China Sea showed an overall decline from 1989 to 2012, remained relatively low since 2005, and slightly increased after 2007. Oyster arsenic levels in Guangdong coastal waters were much higher with more variation than in Guangxi and Hainan coastal waters, and the long-term trends of oyster arsenic levels in Guangdong coastal waters dominated the overall trends of oyster arsenic levels in the coastal waters of northern South China Sea. Within Guangdong Province, oyster arsenic levels were highest in east Guangdong coastal waters, followed by the Pearl River estuary and west Guangdong coastal waters. Single-factor index ranged between 0.27 and 0.97, and average health risk coefficient was 3.85 × 10 -5 , both suggesting that oyster arsenic levels in northern South China Sea are within the safe range for human consumption. However, long-term attention should be given to seafood market monitoring in China and the risk of arsenic exposure to human health through oyster consumption.

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.

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.

Hand controller commonality evaluation process

NASA Technical Reports Server (NTRS)

Stuart, Mark A.; Bierschwale, John M.; Wilmington, Robert P.; Adam, Susan C.; Diaz, Manuel F.; Jensen, Dean G.

1993-01-01

Hand controller selection for NASA's Orbiter and Space Station Freedom is an important area of human-telerobot interface design and evaluation. These input devices will control remotely operated systems that include large crane-like manipulators (e.g., Remote Manipulator System or RMS), smaller, more dexterous manipulators (e.g., Flight Telerobotic Servicer or FTS), and free flyers (e.g., Orbital Maneuvering Vehicle or OMV). Candidate hand controller configurations for these systems vary in many ways: shape, size, number of degrees-of-freedom (DOF), operating modes, provision of force reflection, range of movement, and 'naturalness' of use. Unresolved design implementation issues remain, including such topics as how the current Orbiter RMS rotational and translational rate hand controllers compare with the proposed Space Station Freedom hand controllers, the advantages that position hand controllers offer for these applications, and whether separate hand controller configurations are required for each application. Since previous studies contain little empirical hand controller task performance data, a controlled study is needed that tests Space Station Freedom candidate hand controllers during representative tasks. This study also needs to include anthropometric and biomechanical considerations.

Amorphous calcium carbonate: A precursor phase for aragonite in shell disease of the pearl oyster.

PubMed

Huang, Jingliang; Liu, Chuang; Xie, Liping; Zhang, Rongqing

2018-02-26

Amorphous calcium carbonate (ACC) has long been shown to act as an important constituent or precursor phase for crystalline material in mollusks. However, the presence and the role of ACC in bivalve shell formation are not fully studied. In this study, we found that brown deposits containing heterogeneous calcium carbonates were precipitated when a shell disease occurred in the pearl oyster Pinctada fucata. Calcein-staining of the brown deposits indicated that numerous amorphous calcium deposits were present, which was further confirmed by Fourier-transform infrared spectroscopy (FTIR), Raman spectrum and X-ray difraction (XRD) analyses. So we speculate that ACC plays an important role in rapid calcium carbonate precipitation during shell repair process in diseased oysters. Copyright © 2018 Elsevier Inc. All rights reserved.

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.

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

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

USDA-ARS?s Scientific Manuscript database

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...

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...

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

PubMed Central

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

2012-01-01

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. 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. PMID:23251548

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

[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.

Detection of Vibrio vulnificus biotypes 1 and 2 in eels and oysters by PCR amplification.

PubMed Central

Coleman, S S; Melanson, D M; Biosca, E G; Oliver, J D

1996-01-01

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. PMID:8919800

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

40 CFR 408.160 - Applicability; description of the Alaskan hand-butchered salmon processing subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Alaskan hand-butchered salmon processing subcategory. 408.160 Section 408.160 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Hand-Butchered Salmon Processing Subcategory § 408.160 Applicability; description of the Alaskan hand-butchered salmon processing subcategory. The provisions of this subpart are...

40 CFR 408.160 - Applicability; description of the Alaskan hand-butchered salmon processing subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Alaskan hand-butchered salmon processing subcategory. 408.160 Section 408.160 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Hand-Butchered Salmon Processing Subcategory § 408.160 Applicability; description of the Alaskan hand-butchered salmon processing subcategory. The provisions of this subpart are...

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.

Denitrification potential of the eastern oyster microbiome using a 16S rRNA gene based metabolic inference approach

PubMed Central

Bowman, Jeff S.; Piehler, Michael

2017-01-01

The eastern oyster (Crassostrea virginica) is a foundation species providing significant ecosystem services. However, the roles of oyster microbiomes have not been integrated into any of the services, particularly nitrogen removal through denitrification. We investigated the composition and denitrification potential of oyster microbiomes with an approach that combined 16S rRNA gene analysis, metabolic inference, qPCR of the nitrous oxide reductase gene (nosZ), and N2 flux measurements. Microbiomes of the oyster digestive gland, the oyster shell, and sediments adjacent to the oyster reef were examined based on next generation sequencing (NGS) of 16S rRNA gene amplicons. Denitrification potentials of the microbiomes were determined by metabolic inferences using a customized denitrification gene and genome database with the paprica (PAthway PRediction by phylogenetIC plAcement) bioinformatics pipeline. Denitrification genes examined included nitrite reductase (nirS and nirK) and nitrous oxide reductase (nosZ), which was further subdivided by genotype into clade I (nosZI) or clade II (nosZII). Continuous flow through experiments measuring N2 fluxes were conducted with the oysters, shells, and sediments to compare denitrification activities. Paprica properly classified the composition of microbiomes, showing similar classification results from Silva, Greengenes and RDP databases. Microbiomes of the oyster digestive glands and shells were quite different from each other and from the sediments. The relative abundance of denitrifying bacteria inferred by paprica was higher in oysters and shells than in sediments suggesting that oysters act as hotspots for denitrification in the marine environment. Similarly, the inferred nosZI gene abundances were also higher in the oyster and shell microbiomes than in the sediment microbiome. Gene abundances for nosZI were verified with qPCR of nosZI genes, which showed a significant positive correlation (F1,7 = 14.7, p = 6.0x10-3, R2 = 0

Denitrification potential of the eastern oyster microbiome using a 16S rRNA gene based metabolic inference approach.

PubMed

Arfken, Ann; Song, Bongkeun; Bowman, Jeff S; Piehler, Michael

2017-01-01

The eastern oyster (Crassostrea virginica) is a foundation species providing significant ecosystem services. However, the roles of oyster microbiomes have not been integrated into any of the services, particularly nitrogen removal through denitrification. We investigated the composition and denitrification potential of oyster microbiomes with an approach that combined 16S rRNA gene analysis, metabolic inference, qPCR of the nitrous oxide reductase gene (nosZ), and N2 flux measurements. Microbiomes of the oyster digestive gland, the oyster shell, and sediments adjacent to the oyster reef were examined based on next generation sequencing (NGS) of 16S rRNA gene amplicons. Denitrification potentials of the microbiomes were determined by metabolic inferences using a customized denitrification gene and genome database with the paprica (PAthway PRediction by phylogenetIC plAcement) bioinformatics pipeline. Denitrification genes examined included nitrite reductase (nirS and nirK) and nitrous oxide reductase (nosZ), which was further subdivided by genotype into clade I (nosZI) or clade II (nosZII). Continuous flow through experiments measuring N2 fluxes were conducted with the oysters, shells, and sediments to compare denitrification activities. Paprica properly classified the composition of microbiomes, showing similar classification results from Silva, Greengenes and RDP databases. Microbiomes of the oyster digestive glands and shells were quite different from each other and from the sediments. The relative abundance of denitrifying bacteria inferred by paprica was higher in oysters and shells than in sediments suggesting that oysters act as hotspots for denitrification in the marine environment. Similarly, the inferred nosZI gene abundances were also higher in the oyster and shell microbiomes than in the sediment microbiome. Gene abundances for nosZI were verified with qPCR of nosZI genes, which showed a significant positive correlation (F1,7 = 14.7, p = 6.0x10-3, R2 = 0

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. © 2015 John Wiley & Sons Ltd.

The eastern oyster genome: A resource for comparative genomics in shellfish aquaculture species

USDA-ARS?s Scientific Manuscript database

Oyster aquaculture is an important sector of world food production. As such, it is imperative to develop a high quality reference genome for the eastern oyster, Crassostrea virginica, to assist in the elucidation of the genomic basis of commercially important traits. All genetic, gene expression and...

An oyster species-specific miRNA scaffold42648_5080 modulates haemocyte migration by targeting integrin pathway.

PubMed

Chen, Hao; Wang, Hao; Jiang, Shuai; Xu, Jiachao; Wang, Lingling; Qiu, Limei; Song, Linsheng

2016-10-01

miRNAs are important gene regulators at post-transcriptional level and can modulate diverse biological processes, including immune response. Dozens of species-specific miRNAs have been identified in oyster Crassostrea gigas while their functions remain largely unknown. In the present study, an oyster species-specific miRNA scaffold42648_5080 was found responsive to LPS stimulation and might target a total of 31 oyster genes possibly involved in cell communication, cellular localization and cellular response to stimulus. Besides, in gain-of-function assay of scaffold42648_5080 in vivo, the phagocytosis (30.90% in miRNA group verse 23.20% in miRNA control group), apoptosis (3.10% in miRNA group verse 5.30% in miRNA control group) and migration rate (13.88% in miRNA group verse 21.03% in miRNA control group) of oyster haemocytes were found significantly altered after the injection of scaffold42648_5080 mimics. Among the target genes, integrin-linked kinase (CgILK) was considered crucial in cell migration and its interaction with scaffold42648_5080 was then verified both in vitro and in vivo. Consequently, a significant decrease of relative luciferase ratio was observed in CgILK 3'-UTR luciferase reporter assay after transfection of scaffold42648_5080 mimics (0.70-fold of that in blank group, p < 0.01). Meanwhile, when scaffold42648_5080 was overexpressed in vivo (5.41-fold of miRNA control group, p < 0.01), the expression of CgILK declined significantly to 0.25-fold of miRNA control group (p < 0.01). Comparatively, a significant decrease of the haemocyte migration rate (19.76% verse 34.82% in siEGFP control group, p < 0.01) was observed after knock-down of CgILK in vivo. The present study, as far as we know, for the first time revealed the immunomodulation role of an oyster species-specific miRNA, which might provide new insights into miRNA-mediated adaptation mechanism of oysters. Copyright © 2016 Elsevier Ltd. All rights reserved.

Unusually abundant and large ciliate xenomas in oysters, Crassostrea virginica, from Great Bay, New Hampshire, USA.

PubMed

McGurk, Emily Scarpa; Ford, Susan; Bushek, David

2016-06-01

During routine histological examination of oysters (Crassostrea virginica) from Great Bay, New Hampshire, USA, a high prevalence and intensity of ciliate xenomas has been noted since sampling began in 1997. Xenomas are hypertrophic lesions on the gills of bivalve molluscs caused by intracellular ciliates, likely Sphenophrya sp. Although not known to cause mortality in oysters, xenomas have not previously been reported at this high abundance. The objectives of this study were to characterize the xenomas, describe the ciliates, and gather baseline epizootiological data with correlations to environmental and biological parameters. Upon gross examination, xenomas appeared as white nodules, up to 3mm in diameter, located in the gill tissue and occasionally fusing into large masses along the gill filaments. Light microscopy of histological sections revealed xenomas located in the gill water tubes, which they often completely blocked. Higher magnification revealed dual nuclei, eight kineties, and conjugation of the ciliates. Transmission electron microscopy revealed dual nuclei that varied in density, a maximum of twenty cilia in each kinety radiating from the oral apparatus to the posterior, and a 9+2 axoneme structure within the cilia. These traits place the ciliates into the Order Rhynchodida, but insufficient molecular data exist to confirm classification of this ciliate to the Genus Sphenophrya. Since 1997, xenoma prevalence has fluctuated with peaks in 2000, 2004, and 2011. Infected oysters generally contained <30 xenomas, but 2.1% contained >100, sharply contrasting the rare prevalence and low intensity reported elsewhere. Prevalence increased with oyster size, leveling off near 50% in oysters >60mm. Infection intensity peaked in 70-90mm oysters and declined in larger oysters. Individual oyster condition was not associated with xenoma intensity, but sites with oysters in higher condition generally had a greater prevalence and intensity of xenoma infections

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

OysterFutures: Integrating Stakeholder Objectives with Natural System Models to Promote Sustainable Natural Resource Policy

NASA Astrophysics Data System (ADS)

North, E. W.; Blair, J.; Cornwell, J. C.; Freitag, A. E.; Gawde, R. K.; Hartley, T. W.; Hood, R. R.; Jones, R. M.; Miller, T. J.; Thomas, J. E.; Wainger, L. A.; Wilberg, M. J.

2016-02-01

Achieving effective natural resource management is challenged by multiple and often competing objectives, a restricted set of policy options, and uncertainty in the performance of those options. Yet, managers need policies that allow continued use of natural resources while ensuring access for future generations and maintenance of ecosystem services. Formal approaches are needed that will assist managers and stakeholders in choosing policy options that have a high likelihood of achieving social, ecological, and economic goals. The goal of this project, OysterFutures, is to address this need by improving the use of predictive models to support sustainable natural resource policy and management. A stakeholder-centered process will be used to build an integrated model that combines estuarine physics, oyster life history, and the ecosystem services that oysters provide (e.g., harvest, water quality) to forecast outcomes under alternative management strategies. Through a series of facilitated meetings, stakeholders will participate in a science-based collaborative process which will allow them to project how well policies are expected to meet their objectives using the integrated model. This iterative process will ensure that the model will incorporate the complex human uses of the ecosystem as well as focus on the outcomes most important to the stakeholders. In addition, a study of the socioeconomic drivers of stakeholder involvement, information flow, use and influence, and policy formation will be undertaken to improve the process, enhance implementation success of recommended policies, and provide new ideas for integrating natural and social sciences, and scientists, in sustainable resource management. In this presentation, the strategy for integrating natural system models, stakeholder views, and sociological studies as well as methods for selecting stakeholders and facilitating stakeholder meetings will be described and discussed.

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.

Metal accumulation and differentially expressed proteins in gill of oyster (Crassostrea hongkongensis) exposed to long-term heavy metal-contaminated estuary.

PubMed

Luo, Lianzhong; Ke, Caihuan; Guo, Xiaoyu; Shi, Bo; Huang, Miaoqin

2014-06-01

Bio-accumulation and bio-transmission of toxic metals and the toxicological responses of organisms exposed to toxic metals have been focused, due to heavy metal contaminations have critically threatened the ecosystem and food security. However, still few investigations focused on the responses of certain organisms exposed to the long term and severe heavy metal contamination in specific environments. In present investigation, the Hong Kong oyster, Crassostrea hongkongensis were obtained from 3 sites which were contaminated by different concentrations of heavy metals (such as zinc, copper, manganese and lead etc.), respectively. Heavy metal concentrations in the sea water samples collected from the 3 sites and the dissected tissues of the oysters with blue visceral mass were determinated to estimate the metal contamination levels in environments and the bio-accumulation ratios of the heavy metals in the different tissues of oysters. Moreover, Proteomic methods were employed to analyze the differentially expressed proteins in the gills of oysters exposed to long-term heavy metal contaminations. Results indicated that the Jiulong River estuary has been severely contaminated by Cu, Zn and slightly with Cr, Ni, Mn, etc, moreover, Zn and Cu were the major metals accumulated by oysters to phenomenally high concentrations (more than 3.0% of Zn and about 2.0% of Cu against what the dry weight of tissues were accumulated), and Cr, Ni, Mn, etc were also significantly accumulated. The differentially expressed proteins in the gills of oysters exposed to heavy metals participate in several cell processes, such as metal binding, transporting and saving, oxidative-reduction balance maintaining, stress response, signal transduction, etc. Significantly up-regulated expression (about 10 folds) of an important metal binding protein, metallothionein (MT) and granular cells was observed in the gills of oysters exposed to long-term and severely heavy-metal-contaminated estuary, it

Development and validation of a predictive model for the growth of Vibrio vulnificus in postharvest shellstock oysters.

PubMed

DaSilva, Ligia; Parveen, Salina; DePaola, Angelo; Bowers, John; Brohawn, Kathy; Tamplin, Mark L

2012-03-01

Postharvest growth of Vibrio vulnificus in oysters can increase risk of human infection. Unfortunately, limited information is available regarding V. vulnificus growth and survival patterns over a wide range of storage temperatures in oysters harvested from different estuaries and in different oyster species. In this study, we developed a predictive model for V. vulnificus growth in Eastern oysters (Crassostrea virginica) harvested from Chesapeake Bay, MD, over a temperature range of 5 to 30°C and then validated the model against V. vulnificus growth rates (GRs) in Eastern and Asian oysters (Crassostrea ariakensis) harvested from Mobile Bay, AL, and Chesapeake Bay, VA, respectively. In the model development studies, V. vulnificus was slowly inactivated at 5 and 10°C with average GRs of -0.0045 and -0.0043 log most probable number (MPN)/h, respectively. Estimated average growth rates at 15, 20, 25, and 30°C were 0.022, 0.042, 0.087, and 0.093 log MPN/h, respectively. With respect to Eastern oysters, bias (B(f)) and accuracy (A(f)) factors for model-dependent and -independent data were 1.02 and 1.25 and 1.67 and 1.98, respectively. For Asian oysters, B(f) and A(f) were 0.29 and 3.40. Residual variations in growth rate about the fitted model were not explained by season, region, water temperature, or salinity at harvest. Growth rate estimates for Chesapeake Bay and Mobile Bay oysters stored at 25 and 30°C showed relatively high variability and were lower than Food and Agricultural Organization (FAO)/WHO V. vulnificus quantitative risk assessment model predictions. The model provides an improved tool for designing and implementing food safety plans that minimize the risk associated with V. vulnificus in oysters.

Case study on the orientation of phaco hand pieces during steam sterilization processes.

PubMed

van Doornmalen Gomez Hoyos, J P C M; van Wezel, R A C; van Doornmalen, H W J M

2015-05-01

Steam sterilization is an essential part of infection prevention. The literature shows that sterilization of medical instruments containing channels is not trivial. Phaco hand pieces have a simple configuration: a device contains a channel with a constant radius. No literature was found indicating whether the sterilization conditions on the inner surface of a phaco hand piece are influenced by the orientation of the hand piece. To determine whether the orientation of a phaco hand piece influences the results of a sterilization process of this device. A qualitative case study, including experiments, is performed with a protocolled combination of steam sterilizer, process, phaco hand piece, orientation of the phaco hand piece, and wrapping. In this specific case, the orientation of the hand piece influenced the result of the steam sterilization process; in vertically (upright) oriented phaco hand pieces with free water drainage, sterilization conditions are reproducibly established. In the same process, in horizontally oriented or vertically oriented hand pieces without free drainage, these conditions are not established in a reproducible way. In the investigated combination of sterilizer, process, load, loading pattern and wrapping, phaco hand pieces have to be oriented vertically (upright) with free water drainage to obtain steam sterilization conditions on the inner surface. It is likely that instruments with comparable configuration and dimensions will yield comparable results. It is therefore recommended that this issue is considered during the development of medical instruments and during performance qualifications of such instruments. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

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...

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.

Spatial and temporal variations in cadmium concentrations and burdens in the Pacific oyster (Crassostrea gigas) sampled from the Pacific north-west.

PubMed

Bendell, Leah I; Feng, Cindy

2009-08-01

Oysters from the north-west coast of Canada contain high levels of cadmium, a toxic metal, in amounts that exceed food safety guidelines for international markets. A first required step to determine the sources of cadmium is to identify possible spatial and temporal trends in the accumulation of cadmium by the oyster. To meet this objective, rather than sample wild and cultured oysters of unknown age and origin, an oyster "grow-out" experiment was initiated. Cultured oyster seed was suspended in the water column up to a depth of 7 m and the oyster seed allowed to mature a period of 3 years until market size. Oysters were sampled bimonthly and at time of sampling, temperature, chlorophyll-a, turbidity and salinity were measured. Oyster total shell length, dry tissue weights, cadmium concentrations (microg g(-1)) and burdens (microg of cadmium oyster(-1)) were determined. Oyster cadmium concentrations and burdens were then interpreted with respect to the spatial and temporal sampling design as well as to the measured physio-chemical and biotic variables. When expressed as a concentration, there was a marked seasonality with concentrations being greater in winter as compared in summer; however no spatial trend was evident. When expressed as a burden which corrects for differences in tissue mass, there was no seasonality, however cadmium oyster burdens increased from south to north. Comparison of cadmium accumulation rates oyster(-1) among sites indicated three locations, Webster Island, on the west side of Vancouver Island, and two within Desolation Sound, Teakerne Arm and Redonda Bay, where point sources of cadmium which are not present at all other sampling locations may be contributing to overall oyster cadmium burdens. Of the four physio-chemical factors measured only temperature and turbidity weakly correlated with tissue cadmium concentrations (r(2)=-0.13; p<0.05). By expressing oyster cadmium both as concentration and burden, regional and temporal patterns were

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.

In Situ Subcellular Imaging of Copper and Zinc in Contaminated Oysters Revealed by Nanoscale Secondary Ion Mass Spectrometry.

PubMed

Weng, Nanyan; Jiang, Haibo; Wang, Wen-Xiong

2017-12-19

Determining the in situ localization of trace elements at high lateral resolution levels in the biological system is very challenging, but critical for our understanding of metal sequestration and detoxification. Here, the cellular and subcellular distributions of Cu and Zn in contaminated oysters of Crassostrea hongkongensis were for the first time mapped using nanoscale secondary ion mass spectrometry (nanoSIMS). Three types of metal-containing cells were revealed in the gill and mantle of oysters, including Cu-specific hemocytes, Cu and Zn-containing granular hemocytes, and Cu and Zn-containing calcium cells. Obvious intercellular distribution of Cu was found in the gill tissue, indicating the potential role of hemolymph in the transportation of Cu in oysters. The distribution of Cu showed a strong colocalization with sulfur and nitrogen in Cu-specific hemocyte and intercellular hemolymph. In the Cu and Zn-containing granular hemocytes and calcium cells, the co-occurrence of Cu and Zn with phosphorus and calcium was also found. Different relationships of distributions between Cu/Zn and macronutrient elements (nitrogen, sulfur and phosphorus) implied the differential metal complexation in oysters. Interestingly, quantitative analysis of the ratios of 32 S - / 12 C 14 N - and 31 P - / 12 C 14 N - of metal-deposited sites suggested the dynamic process of transfer of Cu and Zn from the metabolized protein pool to a more thermodynamically stable and detoxified form.

Grasp posture alters visual processing biases near the hands

PubMed Central

Thomas, Laura E.

2015-01-01

Observers experience biases in visual processing for objects within easy reach of their hands that may assist them in evaluating items that are candidates for action. I investigated the hypothesis that hand postures affording different types of actions differentially bias vision. Across three experiments, participants performed global motion detection and global form perception tasks while their hands were positioned a) near the display in a posture affording a power grasp, b) near the display in a posture affording a precision grasp, or c) in their laps. Although the power grasp posture facilitated performance on the motion task, the precision grasp posture instead facilitated performance on the form task. These results suggest that the visual system weights processing based on an observer’s current affordances for specific actions: fast and forceful power grasps enhance temporal sensitivity, while detail-oriented precision grasps enhance spatial sensitivity. PMID:25862545

Apparent Loss of Vibrio vulnificus from North Carolina Oysters Coincides with a Drought-Induced Increase in Salinity

PubMed Central

Froelich, Brett A.; Williams, Tiffany C.; Noble, Rachel T.

2012-01-01

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. PMID:22447591

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.

Expression Characterization of Stress Genes Under High and Low Temperature Stresses in the Pacific Oyster, Crassostrea gigas.

PubMed

Zhu, Qihui; Zhang, Linlin; Li, Li; Que, Huayong; Zhang, Guofan

2016-04-01

As a characteristic sessile inhabitant of the intertidal zone, the Pacific oyster Crassostrea gigas occupies one of the most physically stressful environments on earth. With high exposure to terrestrial conditions, oysters must tolerate broad fluctuations in temperature range. However, oysters' cellular and molecular responses to temperature stresses have not been fully characterized. Here, we analyzed oyster transcriptome data under high and low temperatures. We also identified over 30 key temperature stress-responsive candidate genes, which encoded stress proteins such as heat shock proteins and apoptosis-associated proteins. The expression characterization of these genes under short-term cold and hot environments (5 and 35 °C) and long-term cold environments (5 °C) was detected by quantitative real-time PCR. Most of these genes reached expression peaks during the recovery stage after 24 h of heat stress, and these genes were greatly induced around day 3 in long-term cold stress while responded little to short-term cold stress. In addition, in the second heat stress after 2 days of recovery, oysters showed milder expression in these genes and a lower mortality rate, which indicated the existence of plasticity in the oyster's response to heat stress. We confirmed that homeostatic flexibility and anti-apoptosis might be crucial centers of temperature stress responses in oysters. Furthermore, we analyzed stress gene families in 11 different species and found that the linage-specific expansion of stress genes might be implicated in adaptive evolution. These results indicated that both plasticity and evolution played an important role in the stress response adaptation of oysters.

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...

Sensitivity to ocean acidification differs between populations of the Sydney rock oyster: Role of filtration and ion-regulatory capacities.

PubMed

Stapp, Laura S; Parker, Laura M; O'Connor, Wayne A; Bock, Christian; Ross, Pauline M; Pörtner, Hans O; Lannig, G

2018-04-01

Understanding mechanisms of intraspecific variation in resilience to environmental drivers is key to predict species' adaptive potential. Recent studies show a higher CO 2 resilience of Sydney rock oysters selectively bred for increased growth and disease resistance ('selected oysters') compared to the wild population. We tested whether the higher resilience of selected oysters correlates with an increased ability to compensate for CO 2 -induced acid-base disturbances. After 7 weeks of exposure to elevated seawater PCO 2 (1100 μatm), wild oysters had a lower extracellular pH (pH e = 7.54 ± 0.02 (control) vs. 7.40 ± 0.03 (elevated PCO 2 )) and increased hemolymph PCO 2 whereas extracellular acid-base status of selected oysters remained unaffected. However, differing pH e values between oyster types were not linked to altered metabolic costs of major ion regulators (Na + /K + -ATPase, H + -ATPase and Na + /H + -exchanger) in gill and mantle tissues. Our findings suggest that selected oysters possess an increased systemic capacity to eliminate metabolic CO 2 , possibly through higher and energetically more efficient filtration rates and associated gas exchange. Thus, effective filtration and CO 2 resilience might be positively correlated traits in oysters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). American Oyster.

DTIC Science & Technology

1986-07-01

umbones are usually straight. extends to the Yucatan Peninsula Single oysters from hard substrates of Mexico and the West Indies to are rounded and...season (Merrill and Boss postulated that phytoplankton blooms 1966). Kennedy and Krantz (1982) and nutrition may be responsible for documented the... nutritional factors which affect tidal American oyster Crassostrea the growth and setting of the virygnica (Gmelin). Ph.D. Thesis. larvae of the oyster

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Couch, D.; Hassler, T.J.

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 andmore » loss of habitat. 32 refs., 2 figs.« less

Geophysical mapping of oyster habitats in a shallow estuary; Apalachicola Bay, Florida

USGS Publications Warehouse

Twichell, David C.; Andrews, Brian D.; Edmiston, H. Lee; Stevenson, William R.

2007-01-01

This report presents high-resolution geophysical data, interpretive maps, and a preliminary discussion about the oyster habitat and estuary-floor geology within Apalachicola Bay, Florida (fig. 1). During two research cruises, conducted in 2005 and 2006, approximately 230 km² of the bay floor were surveyed using interferometric-bathymetry, sidescan-sonar, and chirp seismic-reflection techniques. The research was conducted as part of a cooperative program between the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration Coastal Services Center (CSC), and the Apalachicola Bay National Estuarine Research Reserve. The Apalachicola Bay National Estuarine Research Reserve was established in 1979 to provide opportunities for long-term monitoring and research to provide a basis for more informed coastal management decisions for this estuary. Apalachicola Bay is the largest oyster fishery in Florida (Whitfield and Beaumariage, 1977), and the primary objective of this program is to develop a suite of maps that define oyster habitat distribution and estuary-floor geology within the bay. The resulting maps will assist in effective management of oyster resources and provide a reference geologic framework for future scientific and applied research.

Tethered by Self-Generated Flow: Mucus String Augmented Feeding Current Generation in Larval Oysters

NASA Astrophysics Data System (ADS)

Jiang, H.; Wheeler, J.; Anderson, E.

2016-02-01

Marine zooplankton live in a nutritionally dilute environment. To survive, they must process an enormous volume of water relative to their own body volume for food. To achieve this, many zooplankters including copepods, invertebrate larvae, and protists create a feeding current to concentrate and transport food items to their food gathering structures. To enhance the efficiency of the feeding current, these zooplankters often rely on certain "tethering" mechanisms to retard their translational motion for producing a strong feeding current. The tethering force may include excess weight due to gravity, force from attachment to solid surfaces, and drag experienced by strategically placed morphological structures. Larval oysters are known from previous studies to release mucus strings during feeding, presumably for supplying a tethering force to enhance their feeding-current efficiency. But the underlying mechanism is unclear. In this study, we used a high-speed microscale imaging system (HSMIS) to observe the behavior of freely swimming and feeding larval oysters. We also used HSMIS to measure larval imposed feeding currents via a micro-particle image velocimetry (µPIV) technique. HSMIS allows observations along a vertically oriented focal plane in a relatively large water vessel with unprecedented spatial and temporal resolutions. Our high-speed videos show that a feeding larval oyster continuously released a long mucus string into its feeding current that flows downward; the feeding current subsequently dragged the mucus string downward. Analysis of our µPIV data combined with a hydrodynamic model further suggests that the drag force experienced by the mucus string in the feeding current contributes significantly to the tethering force required to generate the feeding current. Thus, mucus strings in larval oysters act as "anchors" in larval self-generated flow to actively tether the feeding larvae.

Fragmentation of the large subunit ribosomal RNA gene in oyster mitochondrial genomes.

PubMed

Milbury, Coren A; Lee, Jung C; Cannone, Jamie J; Gaffney, Patrick M; Gutell, Robin R

2010-09-02

Discontinuous genes have been observed in bacteria, archaea, and eukaryotic nuclei, mitochondria and chloroplasts. Gene discontinuity occurs in multiple forms: the two most frequent forms result from introns that are spliced out of the RNA and the resulting exons are spliced together to form a single transcript, and fragmented gene transcripts that are not covalently attached post-transcriptionally. Within the past few years, fragmented ribosomal RNA (rRNA) genes have been discovered in bilateral metazoan mitochondria, all within a group of related oysters. In this study, we have characterized this fragmentation with comparative analysis and experimentation. We present secondary structures, modeled using comparative sequence analysis of the discontinuous mitochondrial large subunit rRNA genes of the cupped oysters C. virginica, C. gigas, and C. hongkongensis. Comparative structure models for the large subunit rRNA in each of the three oyster species are generally similar to those for other bilateral metazoans. We also used RT-PCR and analyzed ESTs to determine if the two fragmented LSU rRNAs are spliced together. The two segments are transcribed separately, and not spliced together although they still form functional rRNAs and ribosomes. Although many examples of discontinuous ribosomal genes have been documented in bacteria and archaea, as well as the nuclei, chloroplasts, and mitochondria of eukaryotes, oysters are some of the first characterized examples of fragmented bilateral animal mitochondrial rRNA genes. The secondary structures of the oyster LSU rRNA fragments have been predicted on the basis of previous comparative metazoan mitochondrial LSU rRNA structure models.

Effect of intertidal exposure on Vibrio parahaemolyticus levels in Pacific Northwest oysters.

PubMed

Nordstrom, J L; Kaysner, C A; Blackstone, G M; Vickery, M C L; Bowers, J C; DePaola, A

2004-10-01

Interest in Vibrio parahaemolyticus (Vp) increased in the United States following Vp-associated gastroenteritis outbreaks in 1997 and 1998 involving the West Coast and other areas. The present study evaluated multiple aspects of Vp ecology in the Pacific Northwest with three objectives: (i) to determine the effect of low-tide exposure on Vp levels in oysters, (ii) to determine the relationship between total and pathogenic Vp, and (iii) to examine sediments and aquatic fauna as reservoirs for pathogenic Vp. Samples were collected from intertidal reefs along Hood Canal, Wash., in August 2001. Fecal matter from marine mammals and aquatic birds as well as intestinal contents from bottom-dwelling fish were tested. Total and pathogenic Vp levels in all the samples were enumerated with colony hybridization procedures using DNA probes that targeted the thermolabile direct hemolysin (tlh) and thermostable direct hemolysin (tdh) genes, respectively. The mean Vp densities in oysters were four to eight times greater at maximum exposure than at the corresponding first exposure. While tdh-positive Vp counts were generally < or = 10 CFU/g at first exposure, counts as high as 160 CFU/g were found at maximum exposure. Vp concentrations in sediments were not significantly different from those in oysters at maximum exposure. Pathogenic (tdh positive) Vp was detected in 9 of 42 (21%) oyster samples at maximum exposure, in 5 of 19 (26%) sediment samples, but in 0 of 9 excreta samples. These results demonstrate that summer conditions permit the multiplication of Vp in oysters exposed by a receding tide.

Effects of ambient exposure, refrigeration, and icing on Vibrio vulnificus and Vibrio parahaemolyticus abundances in oysters.

PubMed

Jones, J L; Lydon, K A; Kinsey, T P; Friedman, B; Curtis, M; Schuster, R; Bowers, J C

2017-07-17

Vibrio vulnificus (Vv) and V. parahaemolyticus (Vp) illnesses are typically acquired through the consumption of raw molluscan shellfish, particularly oysters. As Vibrio spp. are naturally-occurring bacteria, one means of mitigation of illness is achieved by limiting post-harvest growth. In this study, effects of ambient air storage, refrigeration, and icing of oysters on Vibrio spp. abundances were examined at two sites in Alabama (AL) [Dog River (DR) and Cedar Point (CP)] and one site in Delaware Bay, New Jersey (NJ). As the United States shellfish program recommendations include testing for total these organisms and gene targets, Vv and total (tlh) and pathogenic (tdh+ and trh+) Vp were enumerated from samples using MPN-real-time-PCR approaches. Mean Vv and Vp abundances in oysters from AL-DR were lowest in immediately iced samples (2.3 and -0.1 log MPN/g, respectively) and highest in the 5h ambient then refrigerated samples (3.4 and 0.5 log MPN/g, respectively). Similarly, in AL-CP Vv and Vp mean levels in oysters were lowest in immediately iced samples (3.6 and 1.2 log MPN/g, respectively) and highest in 5h ambient then refrigerated samples (5.1 and 3.2 log MPN/g, respectively). Mean levels of pathogenic Vp from AL sites were frequently below the limit of detection (<0.3 MPN/g). In NJ, Vv and Vp mean abundances in oysters were highest in samples which were held for 7h in the shade (5.3 and 4.8 log MPN/g, respectively). Mean pathogenic Vp levels in oysters at initial harvest were also highest in oysters 7h in the shade (2.1 and 2.2 log MPN/g for tdh+ and trh+ Vp). Regardless of sampling location, Vibrio spp. levels were generally significantly (p<0.05) greater in oysters exposed to 5h of air storage compared to the initially harvested samples. In addition, the data demonstrated that the use of layered ice resulted in lower Vibrio spp. levels in oysters, compared to those that were refrigerated post-harvest. These results suggest vibriosis risk can be mitigated

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

Emergence of a new Vibrio parahaemolyticus serotype in raw oysters: A prevention quandary.

PubMed

Daniels, N A; Ray, B; Easton, A; Marano, N; Kahn, E; McShan, A L; Del Rosario, L; Baldwin, T; Kingsley, M A; Puhr, N D; Wells, J G; Angulo, F J

2000-09-27

In May and June 1998, reported Vibrio parahaemolyticus infections increased sharply in Texas. To determine factors that contributed to the increase in V parahaemolyticus infections. Cross-sectional survey of persons reporting gastroenteritis after eating seafood in Texas; survey of environmental conditions in Galveston Bay. Traceback of oysters, water quality measures in harvest areas, presence of V parahaemolyticus in stool cultures; comparison of median values for environmental conditions before and during the outbreak compared with during the previous 5 years. Between May 31 and July 10, 1998, 416 persons in 13 states reported having gastroenteritis after eating oysters harvested from Galveston Bay. All 28 available stool specimens from affected persons yielded V parahaemolyticus serotype O3:K6 isolates. Oyster beds met current bacteriologic standards during harvest and fecal coliform counts in water samples were within acceptable limits. Median water temperature and salinity during May and June 1998 were 30.0 degrees C and 29.6 parts per thousand (ppt) compared with 28.9 degrees C and 15.6 ppt for the previous 5 years (P<.001). This is the first reported outbreak of V parahaemolyticus serotype O3:K6 infection in the United States. The emergence of a virulent serotype and elevated seawater temperatures and salinity levels may have contributed to this large multistate outbreak of V parahaemolyticus. Bacteriologic monitoring at harvest sites did not prevent this outbreak, suggesting that current policy and regulations regarding the safety of raw oysters require reevaluation. Consumers and physicians should understand that raw or undercooked oysters can cause illness even if harvested from monitored beds. In patients who develop acute gastroenteritis within 4 days of consuming raw or undercooked oysters, a stool specimen should be tested for Vibrio species using specific media. JAMA. 2000;284:1541-1545.

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.

Changes in the microbiological quality of mangrove oysters (Crassostrea brasiliana) during different storage conditions.

PubMed

Montanhini, Maike Taís Maziero; Montanhini Neto, Roberto

2015-01-01

This study aimed to determine the effect of temperature and period of postharvest storage on the microbiological quality and shelf life of raw mangrove oysters, Crassostrea brasiliana. A total of 150 dozen oysters were collected directly from the points of extraction or cultivation in southern Brazil, and in the laboratory, they were stored raw at 5, 10, 15, 20, and 25°C for 1, 4, 8, 11, and 15 days. On each of these days, the oysters were subjected to microbiological analyses of aerobic mesophilic count, total coliforms, enterococci, Escherichia coli, Staphylococcus aureus, and Salmonella. None of the tested samples under any storage condition showed contamination levels above those allowed by Brazilian legislation for E. coli, S. aureus, and Salmonella, and there was no change (P > 0.05) in the counts of these microorganisms due to the temperature and/or period of oyster storage. Counts of enterococci and total coliforms showed a tendency to increase (P < 0.05) among the different temperatures tested. Raw mangrove oysters remain in safe microbiological conditions for consumption up to 8 days after harvesting, regardless of temperature, and their shelf life may be extended to 15 days if they are stored at temperatures not exceeding 15°C.

A homeodomain transcription factor gene, PfMSX, activates expression of Pif gene in the pearl oyster Pinctada fucata.

PubMed

Zhao, Mi; He, Maoxian; Huang, Xiande; Wang, Qi

2014-01-01

We reported pearl oyster Pinctada fucata cDNA and genomic characterization of a new homeobox-containing protein, PfMSX. The PfMSX gene encodes a transcription factor that was localized to the nucleus. Analyses of PfMSX mRNA in tissues and developmental stages showed high expressions in mantle or D-shaped larvae. In electrophoretic mobility shift assays (EMSAs) PfMSX binded to MSX consensus binding sites in the 5' flanking region of the Pif promoter. In co-transfection experiment PfMSX transactivated reporter constructs containing Pif promoter sequences, and mutation of the MSX-binding sites attenuated transactivation. A knockdown experiment using PfMSX dsRNA showed decreased Pif mRNA and unregular crystallization of the nacreous layer using scanning electron microscopy. Our results suggested that PfMSX was a conserved homeodomain transcription factor gene, which can activate Pif gene expression through MSX binding site, and was then involved in the mineralization process in pearl oyster Pinctada fucata. Our data provided important clues about mechanisms regulating biomineralization in pearl oyster.

A Homeodomain Transcription Factor Gene, PfMSX, Activates Expression of Pif Gene in the Pearl Oyster Pinctada fucata

PubMed Central

Zhao, Mi; He, Maoxian; Huang, Xiande; Wang, Qi

2014-01-01

We reported pearl oyster Pinctada fucata cDNA and genomic characterization of a new homeobox-containing protein, PfMSX. The PfMSX gene encodes a transcription factor that was localized to the nucleus. Analyses of PfMSX mRNA in tissues and developmental stages showed high expressions in mantle or D-shaped larvae. In electrophoretic mobility shift assays (EMSAs) PfMSX binded to MSX consensus binding sites in the 5′ flanking region of the Pif promoter. In co-transfection experiment PfMSX transactivated reporter constructs containing Pif promoter sequences, and mutation of the MSX-binding sites attenuated transactivation. A knockdown experiment using PfMSX dsRNA showed decreased Pif mRNA and unregular crystallization of the nacreous layer using scanning electron microscopy. Our results suggested that PfMSX was a conserved homeodomain transcription factor gene, which can activate Pif gene expression through MSX binding site, and was then involved in the mineralization process in pearl oyster Pinctada fucata. Our data provided important clues about mechanisms regulating biomineralization in pearl oyster. PMID:25099698

Interior of processing room. Scale is in front of windows ...

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

Interior of processing room. Scale is in front of windows for weighing shuckers' buckets of oyster meat. Blow tank for thoroughly cleaning the oyster meat and two skimming tables for rinsing and draining can also be seen. - J.C. Lore Oyster House, 14430 Solomons Island Road, Solomons, Calvert County, MD

Susceptibility of Murine Norovirus and Hepatitis A Virus to Electron Beam Irradiation in Oysters and Quantifying the Reduction in Potential Infection Risks

PubMed Central

Praveen, Chandni; Dancho, Brooke A.; Kingsley, David H.; Calci, Kevin R.; Meade, Gloria K.; Mena, Kristina D.

2013-01-01

Consumption of raw oysters is an exposure route for human norovirus (NoV) and hepatitis A virus (HAV). Therefore, efficient postharvest oyster treatment technology is needed to reduce public health risks. This study evaluated the inactivation of HAV and the NoV research surrogate, murine norovirus-1 (MNV-1), in oysters (Crassostrea virginica) by electron beam (E-beam) irradiation. The reduction of potential infection risks was quantified for E-beam irradiation technology employed on raw oysters at various virus contamination levels. The E-beam dose required to reduce the MNV and HAV titer by 90% (D10 value) in whole oysters was 4.05 (standard deviations [SD], ±0.63) and 4.83 (SD, ±0.08) kGy, respectively. Microbial risk assessment suggests that if a typical serving of 12 raw oysters was contaminated with 105 PFU, a 5-kGy treatment would achieve a 12% reduction (from 4.49 out of 10 persons to 3.95 out of 10 persons) in NoV infection and a 16% reduction (from 9.21 out of 10 persons to 7.76 out of 10 persons) in HAV infections. If the serving size contained only 102 PFU of viruses, a 5-kGy treatment would achieve a 26% reduction (2.74 out of 10 persons to 2.03 out of 10 persons) of NoV and 91% reduction (2.1 out of 10 persons to 1.93 out of 100 persons) of HAV infection risks. This study shows that although E-beam processing cannot completely eliminate the risk of viral illness, infection risks can be reduced. PMID:23584781

Susceptibility of murine norovirus and hepatitis A virus to electron beam irradiation in oysters and quantifying the reduction in potential infection risks.

PubMed

Praveen, Chandni; Dancho, Brooke A; Kingsley, David H; Calci, Kevin R; Meade, Gloria K; Mena, Kristina D; Pillai, Suresh D

2013-06-01

Consumption of raw oysters is an exposure route for human norovirus (NoV) and hepatitis A virus (HAV). Therefore, efficient postharvest oyster treatment technology is needed to reduce public health risks. This study evaluated the inactivation of HAV and the NoV research surrogate, murine norovirus-1 (MNV-1), in oysters (Crassostrea virginica) by electron beam (E-beam) irradiation. The reduction of potential infection risks was quantified for E-beam irradiation technology employed on raw oysters at various virus contamination levels. The E-beam dose required to reduce the MNV and HAV titer by 90% (D(10) value) in whole oysters was 4.05 (standard deviations [SD], ±0.63) and 4.83 (SD, ±0.08) kGy, respectively. Microbial risk assessment suggests that if a typical serving of 12 raw oysters was contaminated with 10(5) PFU, a 5-kGy treatment would achieve a 12% reduction (from 4.49 out of 10 persons to 3.95 out of 10 persons) in NoV infection and a 16% reduction (from 9.21 out of 10 persons to 7.76 out of 10 persons) in HAV infections. If the serving size contained only 10(2) PFU of viruses, a 5-kGy treatment would achieve a 26% reduction (2.74 out of 10 persons to 2.03 out of 10 persons) of NoV and 91% reduction (2.1 out of 10 persons to 1.93 out of 100 persons) of HAV infection risks. This study shows that although E-beam processing cannot completely eliminate the risk of viral illness, infection risks can be reduced.

Factors affecting infection of corals and larval oysters by Vibrio coralliilyticus.

PubMed

Ushijima, Blake; Richards, Gary P; Watson, Michael A; Schubiger, Carla B; Häse, Claudia C

2018-01-01

The bacterium Vibrio coralliilyticus can threaten vital reef ecosystems by causing disease in a variety of coral genera, and, for some strains, increases in virulence at elevated water temperatures. In addition, strains of V. coralliilyticus (formally identified as V. tubiashii) have been implicated in mass mortalities of shellfish larvae causing significant economic losses to the shellfish industry. Recently, strain BAA-450, a coral pathogen, was demonstrated to be virulent towards larval Pacific oysters (Crassostrea gigas). However, it is unclear whether other coral-associated V. coralliilyticus strains can cause shellfish mortalities and if infections are influenced by temperature. This study compared dose dependence, temperature impact, and gross pathology of four V. coralliilyticus strains (BAA-450, OCN008, OCN014 and RE98) on larval C. gigas raised at 23°C and 27°C, and evaluated whether select virulence factors are required for shellfish infections as they are for corals. All strains were infectious to larval oysters in a dose-dependent manner with OCN014 being the most pathogenic and BAA-450 being the least. At 27°C, higher larval mortalities (p < 0.05) were observed for all V. coralliilyticus strains, ranging from 38.8-93.7%. Gross pathological changes to the velum and cilia occurred in diseased larvae, but there were no distinguishable differences between oysters exposed to different V. coralliilyticus strains or temperatures. Additionally, in OCN008, the predicted transcriptional regulator ToxR and the outer membrane protein OmpU were important for coral and oyster disease, while mannose sensitive hemagglutinin type IV pili were required only for coral infection. This study demonstrated that multiple coral pathogens can infect oyster larvae in a temperature-dependent manner and identified virulence factors required for infection of both hosts.

High pressure-induced inactivation of Qbeta coliphage and c2 phage in oysters and in culture media.

PubMed

Smiddy, Mary; Kelly, Alan L; Patterson, Margaret F; Hill, Colin

2006-02-01

High pressure (HP) treatment inactivates bacteria in shellfish, but its effects on viruses in shellfish have not yet been determined, although viral illness is frequently associated with shellfish consumption. The aim of this study was to investigate the baroresistance of two bacteriophage viruses, Qbeta coliphage and c2 phage, in oysters and in culture media. High numbers (>or=10(7) ml(-1) or g(-1)) of both phages were obtained in culture media and in oysters. Samples were HP treated at 200-800 MPa at 20 degrees C for up to 30 min. Little or no inactivation of either phage was observed in oysters or in culture media after treatment at oysters and in culture medium were observed following treatment at 500-700 MPa. Titres of both phages were reduced to non-detectable levels (up to 8 log inactivation) in oysters and in GM17 broth (for c2 phage) after treatment at 800 MPa. The level of Qbeta coliphage in tryptone soya broth with yeast extract (10(10) PFU ml(-1)) was reduced by approximately 7 log units following treatment of 800 MPa. Levels of inactivation of both phages in oysters were similar to those in culture media. Increasing the duration of treatment at 550 or 600 MPa increased the level of inactivation of both phages in oysters. HP treatment may effectively inactivate phage in shellfish but HP-induced inactivation of human enteric viruses in oysters needs to be studied directly, to more accurately assess the ability of this technology to inactivate these viruses.

Influence of water temperature and salinity on Vibrio vulnificus in Northern Gulf and Atlantic Coast oysters (Crassostrea virginica).

PubMed

Motes, M L; DePaola, A; Cook, D W; Veazey, J E; Hunsucker, J C; Garthright, W E; Blodgett, R J; Chirtel, S J

1998-04-01

This study investigated the temperature and salinity parameters associated with waters and oysters linked to food-borne Vibrio vulnificus infections. V. vulnificus was enumerated in oysters collected at three northern Gulf Coast sites and two Atlantic Coast sites from July 1994 through September 1995. Two of these sites, Black Bay, La., and Apalachicola Bay, Fla., are the source of the majority of the oysters implicated in V. vulnificus cases. Oysters in all Gulf Coast sites exhibited a similar seasonal distribution of V. vulnificus: a consistently large number (median concentration, 2,300 organisms [most probable number] per g of oyster meat) from May through October followed by a gradual reduction during November and December to < or = 10 per g, where it remained from January through mid-March, and a sharp increase in late March and April to summer levels. V. vulnificus was undetectable (< 3 per g) in oysters from the North and South Carolina sites for most of the year. An exception occurred when a late-summer flood caused a drop in salinity in the North Carolina estuary, apparently causing V. vulnificus numbers to increase briefly to Gulf Coast levels. At Gulf Coast sites, V. vulnificus numbers increased with water temperatures up to 26 degrees C and were constant at higher temperatures. High V. vulnificus levels (> 10(3) per g) were typically found in oysters from intermediate salinities (5 to 25 ppt). Smaller V. vulnificus numbers (< 10(2) per g) were found at salinities above 28 ppt, typical of Atlantic Coast sites. On 11 occasions oysters were sampled at times and locations near the source of oysters implicated in 13 V. vulnificus cases; the V. vulnificus levels and environmental parameters associated with these samples were consistent with those of other study samples collected from the Gulf Coast from April through November. These findings suggest that the hazard of V. vulnificus infection is not limited to brief periods of unusual abundance of V

Influence of Water Temperature and Salinity on Vibrio vulnificus in Northern Gulf and Atlantic Coast Oysters (Crassostrea virginica)

PubMed Central

Motes, M. L.; DePaola, A.; Cook, D. W.; Veazey, J. E.; Hunsucker, J. C.; Garthright, W. E.; Blodgett, R. J.; Chirtel, S. J.

1998-01-01

This study investigated the temperature and salinity parameters associated with waters and oysters linked to food-borne Vibrio vulnificus infections. V. vulnificus was enumerated in oysters collected at three northern Gulf Coast sites and two Atlantic Coast sites from July 1994 through September 1995. Two of these sites, Black Bay, La., and Apalachicola Bay, Fla., are the source of the majority of the oysters implicated in V. vulnificus cases. Oysters in all Gulf Coast sites exhibited a similar seasonal distribution of V. vulnificus: a consistently large number (median concentration, 2,300 organisms [most probable number] per g of oyster meat) from May through October followed by a gradual reduction during November and December to ≤10 per g, where it remained from January through mid-March, and a sharp increase in late March and April to summer levels. V. vulnificus was undetectable (<3 per g) in oysters from the North and South Carolina sites for most of the year. An exception occurred when a late-summer flood caused a drop in salinity in the North Carolina estuary, apparently causing V. vulnificus numbers to increase briefly to Gulf Coast levels. At Gulf Coast sites, V. vulnificus numbers increased with water temperatures up to 26°C and were constant at higher temperatures. High V. vulnificus levels (>103 per g) were typically found in oysters from intermediate salinities (5 to 25 ppt). Smaller V. vulnificus numbers (<102 per g) were found at salinities above 28 ppt, typical of Atlantic Coast sites. On 11 occasions oysters were sampled at times and locations near the source of oysters implicated in 13 V. vulnificus cases; the V. vulnificus levels and environmental parameters associated with these samples were consistent with those of other study samples collected from the Gulf Coast from April through November. These findings suggest that the hazard of V. vulnificus infection is not limited to brief periods of unusual abundance of V. vulnificus in Gulf Coast

Analysis of Pacific oyster larval proteome and its response to high-CO2.

PubMed

Dineshram, R; Wong, Kelvin K W; Xiao, Shu; Yu, Ziniu; Qian, Pei Yuan; Thiyagarajan, Vengatesen

2012-10-01

Most calcifying organisms show depressed metabolic, growth and calcification rates as symptoms to high-CO(2) due to ocean acidification (OA) process. Analysis of the global expression pattern of proteins (proteome analysis) represents a powerful tool to examine these physiological symptoms at molecular level, but its applications are inadequate. To address this knowledge gap, 2-DE coupled with mass spectrophotometer was used to compare the global protein expression pattern of oyster larvae exposed to ambient and to high-CO(2). Exposure to OA resulted in marked reduction of global protein expression with a decrease or loss of 71 proteins (18% of the expressed proteins in control), indicating a wide-spread depression of metabolic genes expression in larvae reared under OA. This is, to our knowledge, the first proteome analysis that provides insights into the link between physiological suppression and protein down-regulation under OA in oyster larvae. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Rhodopsin-Like Gene May Be Associated With the Light-Sensitivity of Adult Pacific Oyster Crassostrea gigas

PubMed Central

Wu, Changlu; Jiang, Qiuyun; Wei, Lei; Cai, Zhongqiang; Chen, Jun; Yu, Wenchao; He, Cheng; Wang, Jiao; Guo, Wen; Wang, Xiaotong

2018-01-01

Light-sensitivity is important for mollusc survival, as it plays a vital role in reproduction and predator avoidance. Light-sensitivity has been demonstrated in the adult Pacific oyster Crassostrea gigas, but the genes associated with light-sensitivity remain unclear. In the present study, we designed experiments to identify the genes associated with light-sensitivity in adult oysters. First, we assessed the Pacific oyster genome and identified 368 genes annotated with the terms associated with light-sensitivity. Second, the function of the four rhodopsin-like superfamily member genes was tested by using RNAi. The results showed that the highest level of mRNA expression of the vision-related genes was in the mantle; however, this finding is not true for all oyster genes. Interestingly, we also found four rhodopsin-like superfamily member genes expressed at an very high level in the mantle tissue. In the RNAi experiment, when one of rhodopsin-like superfamily member genes (CGI_1001253) was inhibited, the light-sensitivity capacity of the injected oysters was significantly reduced, suggesting that CGI_10012534 may be associated with light-sensitivity in the adult Pacific oyster. PMID:29615921

Changes in the Microflora of Haddock Fillets and Shucked Soft-Shelled Clams After Irradiation with Co60 Gamma Rays and Storage at 0 C and 6 C

PubMed Central

Masurovsky, E. B.; Voss, J. S.; Goldblith, S. A.

1963-01-01

Frequency distribution patterns of aerobic-facultative microflora, obtained by random selection of macrocolonies from samples of haddock fillets and shucked soft-shelled clams before and after treatment with doses of from 50,000 to 800,000 rad of Co60 gamma rays, are presented, with analyses and interpretation. The data showed that a decided change occurred in the constitution of the microbial populations of both products: from a mixed gram-negative—gram-positive flora to a predominantly gram-positive flora immediately after irradiation. The great majority of these surviving microorganisms were micrococci, sporeforming bacilli, and certain yeasts, molds, and actinomyces. During storage at refrigeration temperatures above freezing, the microflora changed from the descendants of the more radioresistant gram-positive species to the more prolific gram-negative psychrophilic species that flourish at these low temperatures. Micrococci and gram-positive rods declined somewhat during the rise of the actively proteolytic-lipolytic pseudomonads and related species, but still remained at high enough levels to contribute significantly to the spoilage observed at different times in storage. The eventual spoilage of haddock fillets was characterized by discoloration of the cream-white tissue with water-soluble yellow, green, and red bacterial pigments; degradation of the tissue, by proteolytic and other microbial enzymes, to a watery, flaccid mass; and formation of volatile compounds that smelled putrid, rancid, and generally foul and pungent. Shucked soft-shelled clams displayed a different spoilage pattern, changing to a variegated brown-gray and forming a matted or loose gelatinous mass from which arose stale, acrid, putrid, sulfurous odors. These differences are believed to be attributable to the varied biochemical nature of the tissues involved, the Eh potential within the tissues, the time sequence of microfloral change, and the species and types of microorganisms

40 CFR 408.180 - Applicability; description of the West Coast hand-butchered salmon processing subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Coast hand-butchered salmon processing subcategory. 408.180 Section 408.180 Protection of Environment... PROCESSING POINT SOURCE CATEGORY West Coast Hand-Butchered Salmon Processing Subcategory § 408.180 Applicability; description of the West Coast hand-butchered salmon processing subcategory. The provisions of...

40 CFR 408.180 - Applicability; description of the West Coast hand-butchered salmon processing subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Coast hand-butchered salmon processing subcategory. 408.180 Section 408.180 Protection of Environment... PROCESSING POINT SOURCE CATEGORY West Coast Hand-Butchered Salmon Processing Subcategory § 408.180 Applicability; description of the West Coast hand-butchered salmon processing subcategory. The provisions of...

The use of coconut dregs flour as food fiber and its application to oyster mushroom (reviewed from its nutrition)

NASA Astrophysics Data System (ADS)

Putri, Meddiati Fajri

2018-03-01

The need of fiber is an important thing for a food since it eases the metabolism, places the bacteria in the intestines, and decreases the cholesterol. Coconut dregs has high cellulose to play the role in body's physiology. Cellulose is food fiber which is unable to be digested by enzymes of metabolism. Nevertheless, its role in metabolism is very important to shorten the transition time of food and decrease the risk of intestines cancer. Besides, it can bind the fats, protein, and carbohydrate to form the complexed fat-protein-carbohydrate-fiber. The final form of this complex compound is unable to be digested by digestive enzyme which is excreted with feces. Thus, the consumer can be spared from obesity, hyper-cholesterol, and coronary heart. Oyster mushroom as the substitute ingredients of healthy food has not been revealed to the society. Oyster is a food material which has an excellency of supporting the food security. It is supported by high production, process, and tools potential used in making it to become more useful products. It can be added to breads, food's recipe, and other products as health food to support food diversification. This research is aimed to know the fiber contained in oyster nuggets which has been added with coconut dregs oil. The analysis of the fiber was using Sohxlet methods. The level of fiber in the nuggets with the flour in 6% per 100g was 2.604g. If the nuggets was with white oyster with fiber in each 100 gram of nuggets with 10% flour was 3.644g. In 14% flour of nuggets, the fiber was 4.064g. It can be concluded that the consumption of 100 grams nuggets can give about 2.604-4.064grams of nuggets each day. It means the substitute of oyster to the level of fiber in oyster nugget per 100 grams was 2.604-4.064 gram. Meanwhile, the necessity of food fiber each day is 6-15 grams.

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. Copyright © 2012 Elsevier B.V. All rights reserved.

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...

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...

A norepinephrine-responsive miRNA directly promotes CgHSP90AA1 expression in oyster haemocytes during desiccation.

PubMed

Chen, Hao; Xin, Lusheng; Song, Xiaorui; Wang, Lin; Wang, Weilin; Liu, Zhaoqun; Zhang, Huan; Wang, Lingling; Zhou, Zhi; Qiu, Limei; Song, Linsheng

2017-05-01

Oyster Crassostrea gigas is one model mollusc inhabiting in the intertidal zone and is frequently stressed by desiccation. The adaptation mechanism of oyster to environmental stress involves multiple levels, and miRNA is one of the most important regulators in post-transcriptional level. In the present study, an oyster norepinephrine-responsive miRNA cgi-miR-365 was proved to contribute to the host adaptation against desiccation by directly promoting the expression of CgHSP90AA1. Briefly, a significant increase of cgi-miR-365 was observed from the first day after aerial exposure and the up-regulation was vigorously repressed when oysters were injected with adrenoceptors antagonists. A total of 15 genes involved in biological regulation, metabolic process and response to stimulus were predicted to be modulated by cgi-miR-365. Among these genes, CgHSP90AA1 was up-regulated significantly during desiccation and could be down-regulated after simultaneous injection of adrenoceptors antagonists. The interaction between cgi-miR-365 and CgHSP90AA1 was subsequently verified in vitro, and a significant promotion of CgHSP90AA1 transcripts was observed after overexpressing cgi-miR-365 in either in vitro luciferase reporter assay or primarily cultured haemocytes. Meanwhile, CgHSP90AA1 transcripts decreased in vivo when cgi-miR-365 was repressed by its inhibitor during desiccation. Collectively, it was suggested that cgi-miR-365 could be induced by norepinephrine during desiccation and promote CgHSP90AA1 expression directly after binding to its 3'-UTR, which would provide new evidence in miRNA-mediated adaptation mechanism in oysters against intertidal stress. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Oyster aquaculture impacts Zostera marina epibiont community composition in Akkeshi-ko estuary, Japan

PubMed Central

Nakaoka, Masahiro

2018-01-01

Coastal fisheries are in decline worldwide, and aquaculture has become an increasingly popular way to meet seafood demand. While finfish aquaculture can have substantial adverse effects on coastal ecosystems due mostly to necessary feed inputs, bivalves graze on natural phytoplankton and are often considered for their positive ecosystem services. We conducted two independent studies to investigate the effects of long-line Crassostrea gigas oyster aquaculture on Zostera marina seagrass beds and associated epibiont communities in Akkeshi-ko estuary, Japan. Results from both studies yielded no evidence of an effect of oyster aquaculture on the morphology, density, or biomass of Z. marina, but significant differences were apparent in the epibiont community. Reference seagrass beds located away from aquaculture had higher seagrass epiphyte loads and higher abundances of amphipods. Conversely, seagrass beds below aquaculture lines had higher sessile polychaete biomass and higher isopod abundances. Our results suggest that the presence of oyster aquaculture may have indirect effects on seagrass by changing epibiont community composition and relative abundances of species. One proposed mechanism is that cultured oysters feed on epiphytic diatoms and epiphyte propagules before they can settle on the seagrass, which reduces epiphyte loads and influences subsequent faunal settlement. If carefully implemented and monitored, long-line oyster aquaculture may be a sustainable option to consider as bivalve aquaculture expands to meet global seafood demand, but further work is needed to fully assess and generalize the community-level effects on seagrass epibionts. PMID:29795609

Oyster aquaculture impacts Zostera marina epibiont community composition in Akkeshi-ko estuary, Japan.

PubMed

Smith, Carter S; Ito, Minako; Namba, Mizuho; Nakaoka, Masahiro

2018-01-01

Coastal fisheries are in decline worldwide, and aquaculture has become an increasingly popular way to meet seafood demand. While finfish aquaculture can have substantial adverse effects on coastal ecosystems due mostly to necessary feed inputs, bivalves graze on natural phytoplankton and are often considered for their positive ecosystem services. We conducted two independent studies to investigate the effects of long-line Crassostrea gigas oyster aquaculture on Zostera marina seagrass beds and associated epibiont communities in Akkeshi-ko estuary, Japan. Results from both studies yielded no evidence of an effect of oyster aquaculture on the morphology, density, or biomass of Z. marina, but significant differences were apparent in the epibiont community. Reference seagrass beds located away from aquaculture had higher seagrass epiphyte loads and higher abundances of amphipods. Conversely, seagrass beds below aquaculture lines had higher sessile polychaete biomass and higher isopod abundances. Our results suggest that the presence of oyster aquaculture may have indirect effects on seagrass by changing epibiont community composition and relative abundances of species. One proposed mechanism is that cultured oysters feed on epiphytic diatoms and epiphyte propagules before they can settle on the seagrass, which reduces epiphyte loads and influences subsequent faunal settlement. If carefully implemented and monitored, long-line oyster aquaculture may be a sustainable option to consider as bivalve aquaculture expands to meet global seafood demand, but further work is needed to fully assess and generalize the community-level effects on seagrass epibionts.

Restoration of oyster reefs in an estuarine lake: population dynamics and shell accretion

USGS Publications Warehouse

Casas, Sandra M.; La Peyre, Jerome F.; La Peyre, Megan K.

2015-01-01

Restoration activities inherently depend on understanding the spatial and temporal variation in basic demographic rates of the species of interest. For species that modify and maintain their own habitat such as the eastern oyster Crassostrea virginica, understanding demographic rates and their impacts on population and habitat success are crucial to ensuring restoration success. We measured oyster recruitment, density, size distribution, biomass, mortality and Perkinsus marinus infection intensity quarterly for 3 yr on shallow intertidal reefs created with shell cultch in March 2009. All reefs were located within Sister Lake, LA. Reefs were placed in pairs at 3 different locations within the lake; pairs were placed in low and medium energy sites within each location. Restored reefs placed within close proximity (<8 km) experienced very different development trajectories; there was high inter-site and inter-annual variation in recruitment and mortality of oysters, with only slight variation in growth curves. Despite this high variation in population dynamics, all reefs supported dense oyster populations (728 ± 102 ind. m-2) and high live oyster biomass (>14.6 kg m-2) at the end of 3 yr. Shell accretion, on average, exceeded estimated rates required to keep pace with local subsidence and shell loss. Variation in recruitment, growth and survival drives local site-specific population success, which highlights the need to understand local water quality, hydrodynamics, and metapopulation dynamics when planning restoration.

Overview and comparison of lipid-containing semipermeable membrane devices and oysters (Crassostrea gigas) for assessing organic chemical exposure

USGS Publications Warehouse

Huckins, J.N.; Prest, H.F.; Petty, J.D.; Lebo, J.A.; Hodgins, M.M.; Clark, R.C.; Alvarez, D.A.; Gala, W.R.; Steen, A.; Gale, R.; Ingersoll, C.G.

2004-01-01

We performed 20-d, flow-through exposures of lipid-containing semipermeable membrane devices (SPMDs) and Pacific oysters (Crassostrea gigas) to three concentrations (nominally 10, 100, and 250 ng/L) of a diverse mixture of polycyclic aromatic hydrocarbons (PAHs). Exposure water was seawater free of particulates larger than 0.1 μm. The results of these controlled laboratory studies demonstrated that SPMDs and oysters concentrate the same chemicals but that the relative amounts accumulated are different. For oysters, the 20-d mean (across treatments) concentration factors (CFs) of test compounds with log Kow ≤ 4.8 were much lower (4.0- to 20-fold lower) than those of the same compounds in SPMDs. In contrast, the 20-d CFs of PAHs with log Kow ≥ 5.6 in oysters from the low-level treatment were higher than the corresponding CFs for SPMDs. The CFs of these compounds in oysters from the low-level treatment ranged from approximately 3.0- to 13-fold higher than those in oysters from the high-level treatment. This physiologically mediated difference in oyster CFs appears to be linked to active feeding in the low-level treatment and to apparent toxicity-induced cessation of feeding (i.e., valve closure) in the high-level treatment. Because CFs for these compounds in oysters were not independent of exposure concentrations, it follows that tissue levels were not proportional to exposure concentration. However, both sampling approaches have advantages and disadvantages, and the appropriateness of their use depends on the goals of a given study.

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...

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…

Refining the tethering of American oysters (Crassostrea virginica) to measure the effects of two environmental stressors.

PubMed

Poirier, Luke A; Gilbert, Shane T C; St-Hilaire, Sophie; Davidson, Jeff; Cox, Ruth; Quijón, Pedro A

2018-02-01

Tethering assays, or the physical restraint of test organisms, has been used in the past to measure selected organisms' response to stressors while removing the observer from the experimental setting. Although informative for monitoring and hypothesis testing, these assays often used microfilaments that have been found to be too invasive or prone to biases given their effects on test organisms' behavior. Here, we describe a new variation of tethering using American oysters (Crassostrea virginica) and illustrate its use in the study of their mortality rates as a result of two stressors: siltation and predation by a non-indigenous species. Our protocol identified a resistant (non-toxic) glue that could be used to attach oysters to stone slabs, thus partially mimicking the natural cementation of the shell to natural substrates. This variation of tethering was harmless and maintained oysters' body position and natural ability to filter feed. Using tethered oysters in separate two-week field cage experiments, we also show how siltation and predation by a non-indigenous species (the European green crab, Carcinus maenas), caused a gradual, easily measurable increase in oyster mortality rates. We argue that this variation of tethering is a cost-effective and advantageous way to monitor or test the effects of these and other stressors on oysters and similar species. Copyright © 2017 Elsevier Ltd. All rights reserved.

Occurrence of Vibrio parahaemolyticus and Vibrio vulnificus in retail raw oysters from the eastern coast of Thailand.

PubMed

Changchai, Nuttawee; Saunjit, Sudarat

2014-05-01

Occurrence, population density and virulence of Vibrio parahaemolyticus and V. vulnificus in 240 retail raw oysters collected monthly between March 2010 and February 2011 from Ang Sila coast, Chon Buri Province, Thailand were determined using most probable number (MPN) multiplex PCR. Multiplex PCR detected V. parahaemolyticus in 219 raw oyster samples, of which 29 samples contained the virulence tdh. MPN values for V. parahaemolyticus and pathogenic strains in most samples ranged from 10 to 10(2) and from 3 to 10 MPN/g, respectively. The presence of V. vulnificus was found in 53 oyster samples in amounts between 10 and 10(2) MPN/g. Of 1,087 V. parahaemolyticus isolates, 14 and 2 isolates carried tdh and virulence trh, respectively but none with both genes. However, none of the presumptive isolates was shown to be V. vulnificus. The detection of pathogenic V. parahaemolyticus and V. vulnificus in raw oysters has rendered high awareness of risk in consumption of raw or undercooked oysters.

Application of a phage in decontaminating Vibrio parahaemolyticus in oysters.

PubMed

Zhang, Hui; Yang, Zhenquan; Zhou, Yan; Bao, Hongduo; Wang, Ran; Li, Tingwu; Pang, Maoda; Sun, Lichang; Zhou, Xiaohui

2018-06-20

Vibrio parahaemolyticus is a major pathogen that is mainly associated with seafood and is a global concern of food safety. With high prevalence of contamination in food, efficient strategy is needed to decontaminate those contaminated foods and control the emergence of vibriosis. In the present study, a V. parahaemolyticus-specific phage vB_VpaS_OMN (designated as phage OMN) was isolated from oyster. Phage OMN had good pH (5-9) and temperature tolerance (<50 °C). Phage OMN exhibited broad host range against isolates of V. parahaemolyticus (20/31). After treatment with phage OMN in the liquid condition for 7 h, the number of V. parahaemolyticus was reduced significantly compared to control treatment. When phage OMN was applied to oyster samples for 48 and 72 h, 90% and 99%, respectively, of V. parahaemolyticus was inactivated on Oyster meat surface. Sequence analysis showed that phage OMN had a 42.202 bp genome and revealed about 59.04% homology with Cronobacter phage vB_CsaP_Ss1. Only 10 CDSs can be predicted based on the GenBank database, while 42% of the CDSs were unique to OMN and had no known function, indicating that phage OMN is a new lytic phage. Fully understanding of the function for the phage genes and the properties of the phage is important for the development of strategies to control V. parahaemolyticus contamination in oysters and disease in aquaculture. Copyright © 2018 Elsevier B.V. All rights reserved.

The impact of suspended oyster farming on nitrogen cycling and nitrous oxide production in a sub-tropical Australian estuary

NASA Astrophysics Data System (ADS)

Erler, Dirk V.; Welsh, David T.; Bennet, William W.; Meziane, Tarik; Hubas, Cédric; Nizzoli, Daniele; Ferguson, Angus J. P.

2017-06-01

In this study we quantified nitrate (NO3-) reduction (denitrification, anammox and DNRA) and N2O production in sediments and epibiont communities associated with Sydney Rock Oyster (Saccostrea glomerata) farming. In sediments beneath an active suspended oyster farm, DNRA accounted for 98% of NO3- reduction with rates of up to 169 ± 45 μmol N m-2 h-1. Much of this DNRA was fuelled by NO3- derived from nitrification. Reference sediments had significantly lower DNRA rates of 83.8 ± 28.2 μmol N m-2 h-1, however this constituted 96% of the sites total NO3- reduction. Fatty acid analysis showed that sediment organic matter was more labile in the oyster impacted sediments, facilitating subtle shifts in sediment oxygen demand which increased the Fe2+ availability with respect to the reference sediments. The difference in DNRA rate between the sites was attributed to autotrophic oxidation of soluble Fe2+ in sediments underlying the oyster cultures. DNRA was absent in the oyster shell epibiont communities and rates of anammox and denitrification were lower than in the sediments. Production of NH4+ from the oysters and their associated epibionts was larger than DNRA and reached a rate of 206.2 μmol N m-2 h-1. Nitrous oxide production rates were generally low compared to other aquaculture systems and the net flux of N2O for the combined oyster cultivation system (i.e. sediments plus epibionts) was negative, i.e. there was N2O consumption in the sediments beneath the oysters. Overall, subtropical suspended oyster farming systems favour inorganic N retention over N loss.

Effects of High-Hydrostatic Pressure on Inactivation of Human Norovirus and Physical and Sensory Characteristics of Oysters.

PubMed

Ye, Mu; Lingham, Talaysha; Huang, Yaoxin; Ozbay, Gulnihal; Ji, Lin; Karwe, Mukund; Chen, Haiqiang

2015-06-01

The purpose of the study was to determine the effect of high-hydrostatic pressure (HHP) on inactivation of human norovirus (HuNoV) in oysters and to evaluate organoleptic characteristics of oysters treated at pressure levels required for HuNoV inactivation. Genogroup I.1 (GI.1) or Genogroup II.4 (GII.4) HuNoV was inoculated into oysters and treated at 300 to 600 MPa at 25 and 0 °C for 2 min. After HHP, viral particles were extracted by porcine gastric mucin-conjugated magnetic beads (PGM-MBs) and viral RNA was quantified by real-time RT-PCR. Lower initial temperature (0 °C) significantly enhanced HHP inactivation of HuNoV compared to ambient temperature (25 °C; P < 0.05). HHP at 350 and 500 MPa at 0 °C could achieve more than 4 log10 reduction of GII.4 and GI.1 HuNoV in oysters, respectively. HHP treatments did not significantly change color or texture of oyster tissue. A 1- to 5-scale hedonic sensory evaluation on appearance, aroma, color, and overall acceptability showed that pressure-treated oysters received significantly higher quality scores than the untreated control (P < 0.05). Elevated pressure levels at 450 and 500 MPa did not significantly affect scores compared to 300 MPa at 0 °C, indicating increasing pressure level did not affect sensory acceptability of oysters. Oysters treated at 0 °C had slightly lower acceptability than the group treated at room temperature on day 1 (P < 0.05), but after 1 wk storage, no significant difference in sensory attributes and consumer desirability was observed (P > 0.05). © 2015 Institute of Food Technologists®

DNA barcoding reveals that the common cupped oyster in Taiwan is the Portuguese oyster Crassostrea angulata (Ostreoida; Ostreidae), not C. gigas

PubMed Central

Hsiao, Sheng-Tai; Chuang, Shin-Chang; Chen, Kao-Sung; Ho, Ping-Ho; Wu, Chi-Lun; Chen, Chaolun Allen

2016-01-01

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. PMID:27666088

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.

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.

APPLICATION OF RADIOISOTOPE-LABELED BACTERIA IN FOOD SANITATION STUDIES. IV. ON THE BACTERIAL CONTAMINATION AND DECONTAMINATION OF LIVING OYSTER (in Japanese)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bito, T.; Takase, A.

Decontamination of the living oyster was studied by Y/sup 90/or Y/sup 91/ -labeled coliform bacteria. At low temperature, precultural temperature affected the contamination of the oyster but the uptake of bacteria by the oyster was distinctly observed below 5 deg C. In a study on elapsing change of contamination, it was determined that the whole bacterial load of the oyster depended mainly on the gill, but was not negligible on the digestive tract. The contaminating rate of the oyster was successfully measured by automatic recording of the shift of radioactivity in the contaminated cultural water with a dip-type G-M countermore » ratemeter and chart recorder, because the bacterial concentration of the closed cultural water decrease according to the bacterial uptake of the oyster. On decontamination of the oyster, it was observed that the most effective temperature existed in the region of 15 to 25 deg C, and at the upper or lower of this region the decontaminating efficiency decreased. As for the exchange rate of the culture water, the decontaminating effect on the oyster was proportional to an increase of the rate to 7.5 times per hour. However, more was of no effect. An increase in the cultured water volume was harmful for the decontamination of the oyster because of the exchanging efficiency of the water. (P.C.H.)« less

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.

Role and Value of Nitrogen Regulation Provided by Oysters (Crassostrea virginica) in the Mission-Aransas Estuary, Texas, USA

PubMed Central

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. PMID:23762341

Denitrification and Phosphorus Sequestration in Restored Oyster Beds in the Indian River Lagoon, Florida, USA

NASA Astrophysics Data System (ADS)

Gallagher, S. M.; Schmidt, C. A.; Walters, L.

2016-12-01

In 2016, an algae bloom in the St. Lucie River in Florida led the governor to declare a state of emergency. The river is part of a connected system of estuaries along the Atlantic coast of Florida called the Indian River Lagoon (IRL). As with many estuaries around the world, nutrient loading in the IRL has led to periodic eutrophication. As a result, much research has been done to address nutrients in these systems. Previous estuary studies have related oyster restoration to denitrification and phosphorus sequestration in their bed sediment. To this point, these studies have been inconclusive, and have only focused on seasonal variation in nutrient cycling. In 2007, yearly oyster bed installation and restoration began in a study area in the IRL. By 2016, beds aged up to eleven years were available for sampling. This unique advantage allowed investigation of bed sediment and nutrient cycling over long periods of time. Sediment from the IRL was measured for organic matter, microbial weight, carbon, nitrogen, and phosphorus. Denitrification was measured using an acetylene block technique. A statistical analysis was used to find differences in sediment characteristics and denitrification between restored beds and control sites over time. In addition, sequencing of 16S rRNA DNA and a variety of denitrifying genes was used to identify bacterial species and their denitrifying capability in the sediment. The ability to sequence denitrification genes in established oyster beds over a period of years was also unique to this study. Significant differences were found in soil properties, denitrification rates, and phosphorus sequestration between control sites and restored oyster beds. Gene sequencing also found differences in bacterial populations between the sites. Oyster bed restoration resulted in a rapid increase in nutrient removal as beds developed over three years, but additional benefits were limited as restoration progressed further. This study adds an investigation

A Nonautochthonous U.S. Strain of Vibrio parahaemolyticus Isolated from Chesapeake Bay Oysters Caused the Outbreak in Maryland in 2010

PubMed Central

Haendiges, Julie; Jones, Jessica; Myers, Robert A.; Mitchell, Clifford S.; Butler, Erin

2016-01-01

ABSTRACT In the summer of 2010, Vibrio parahaemolyticus caused an outbreak in Maryland linked to the consumption of oysters. Strains isolated from both stool and oyster samples were indistinguishable by pulsed-field gel electrophoresis (PFGE). However, the oysters contained other potentially pathogenic V. parahaemolyticus strains exhibiting different PFGE patterns. In order to assess the identity, genetic makeup, relatedness, and potential pathogenicity of the V. parahaemolyticus strains, we sequenced 11 such strains (2 clinical strains and 9 oyster strains). We analyzed these genomes by in silico multilocus sequence typing (MLST) and determined their phylogeny using a whole-genome MLST (wgMLST) analysis. Our in silico MLST analysis identified six different sequence types (STs) (ST8, ST676, ST810, ST811, ST34, and ST768), with both of the clinical and four of the oyster strains being identified as belonging to ST8. Using wgMLST, we showed that the ST8 strains from clinical and oyster samples were nearly indistinguishable and belonged to the same outbreak, confirming that local oysters were the source of the infections. The remaining oyster strains were genetically diverse, differing in >3,000 loci from the Maryland ST8 strains. eBURST analysis comparing these strains with strains of other STs available at the V. parahaemolyticus MLST website showed that the Maryland ST8 strains belonged to a clonal complex endemic to Asia. This indicates that the ST8 isolates from clinical and oyster sources were likely not endemic to Maryland. Finally, this study demonstrates the utility of whole-genome sequencing (WGS) and associated analyses for source-tracking investigations. IMPORTANCE Vibrio parahaemolyticus is an important foodborne pathogen and the leading cause of bacterial infections in the United States associated with the consumption of seafood. In the summer of 2010, Vibrio parahaemolyticus caused an outbreak in Maryland linked to oyster consumption. Strains isolated

A Nonautochthonous U.S. Strain of Vibrio parahaemolyticus Isolated from Chesapeake Bay Oysters Caused the Outbreak in Maryland in 2010.

PubMed

Haendiges, Julie; Jones, Jessica; Myers, Robert A; Mitchell, Clifford S; Butler, Erin; Toro, Magaly; Gonzalez-Escalona, Narjol

2016-06-01

In the summer of 2010, Vibrio parahaemolyticus caused an outbreak in Maryland linked to the consumption of oysters. Strains isolated from both stool and oyster samples were indistinguishable by pulsed-field gel electrophoresis (PFGE). However, the oysters contained other potentially pathogenic V. parahaemolyticus strains exhibiting different PFGE patterns. In order to assess the identity, genetic makeup, relatedness, and potential pathogenicity of the V. parahaemolyticus strains, we sequenced 11 such strains (2 clinical strains and 9 oyster strains). We analyzed these genomes by in silico multilocus sequence typing (MLST) and determined their phylogeny using a whole-genome MLST (wgMLST) analysis. Our in silico MLST analysis identified six different sequence types (STs) (ST8, ST676, ST810, ST811, ST34, and ST768), with both of the clinical and four of the oyster strains being identified as belonging to ST8. Using wgMLST, we showed that the ST8 strains from clinical and oyster samples were nearly indistinguishable and belonged to the same outbreak, confirming that local oysters were the source of the infections. The remaining oyster strains were genetically diverse, differing in >3,000 loci from the Maryland ST8 strains. eBURST analysis comparing these strains with strains of other STs available at the V. parahaemolyticus MLST website showed that the Maryland ST8 strains belonged to a clonal complex endemic to Asia. This indicates that the ST8 isolates from clinical and oyster sources were likely not endemic to Maryland. Finally, this study demonstrates the utility of whole-genome sequencing (WGS) and associated analyses for source-tracking investigations. Vibrio parahaemolyticus is an important foodborne pathogen and the leading cause of bacterial infections in the United States associated with the consumption of seafood. In the summer of 2010, Vibrio parahaemolyticus caused an outbreak in Maryland linked to oyster consumption. Strains isolated from stool and oyster

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.

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...

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...

Oyster Shell Recycling and Bone Waste Treatment Using Plasma Pyrolysis

NASA Astrophysics Data System (ADS)

Jae, Ou Chae; Knak, S. P.; Knak, A. N.; Koo, H. J.; Ravi, V.

2006-11-01

Investigations on the recycling of oyster shells and bone waste treatment using the plasma pyrolysis technique are presented in this paper. A arc based plasma torch operated at 25 kW was employed for the experiments. Fresh oyster shells were recycled using the plasma torch to convert them to a useful product such as CaO. Bone waste was treated to remove the infectious organic part and to vitrify the inorganic part. The time required for treatment in both cases was significantly short. Significant reduction in the weight of the samples was observed in both cases.

The hand surgery fellowship application process: expectations, logistics, and costs.

PubMed

Meals, Clifton; Osterman, Meredith

2015-04-01

To investigate expectations, logistics, and costs relevant to the hand surgery fellowship application process. We sought to discover (1) what both applicants and program directors are seeking, (2) what both parties have to offer, (3) how both parties collect information about each other, and (4) the costs incurred in arranging each match. We conducted on-line surveys of hand surgery fellowship applicants for appointment in 2015 and of current fellowship program directors. Sixty-two applicants and 41 program directors completed the survey. Results revealed applicants' demographic characteristics, qualifications, method of ranking hand fellowship programs, costs incurred (both monetary and opportunity) during the application process, ultimate match status, and suggestions for change. Results also revealed program directors' program demographics, rationale for offering interviews and favorably ranking applicants, application-related logistical details, costs incurred (both monetary and opportunity) during the application process, and suggestions for change. Applicants for hand surgery fellowship training are primarily interested in a potential program's academic reputation, emphasis on orthopedic surgery, and location. The typical, successfully matched applicant was a 30-year-old male orthopedic resident with 3 publications to his credit. Applicants rely on peers and Web sites for information about fellowships. Fellowship directors are primarily seeking applicants recommended by other experienced surgeons and with positive personality traits. The typical fellowship director offers a single year of orthopedic-based fellowship training to 2 fellows per year and relies on a common application and in-person interviews to collect information about applicants. Applicants appear to be more concerned than directors about the current state of the match process. Applicants and directors alike incur heavy costs, in both dollars and opportunity, to arrange each match. A nuanced

Network analysis of oyster transcriptome revealed a cascade of cellular responses during recovery after heat shock.

PubMed

Zhang, Lingling; Hou, Rui; Su, Hailin; Hu, Xiaoli; Wang, Shi; Bao, Zhenmin

2012-01-01

Oysters, as a major group of marine bivalves, can tolerate a wide range of natural and anthropogenic stressors including heat stress. Recent studies have shown that oysters pretreated with heat shock can result in induced heat tolerance. A systematic study of cellular recovery from heat shock may provide insights into the mechanism of acquired thermal tolerance. In this study, we performed the first network analysis of oyster transcriptome by reanalyzing microarray data from a previous study. Network analysis revealed a cascade of cellular responses during oyster recovery after heat shock and identified responsive gene modules and key genes. Our study demonstrates the power of network analysis in a non-model organism with poor gene annotations, which can lead to new discoveries that go beyond the focus on individual genes.

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…

Investigation of acidity and other water-quality characteristics of Upper Oyster Creek, Ocean County, New Jersey

USGS Publications Warehouse

Fusillo, Thomas V.; Schornick, J.C.; Koester, H.E.; Harriman, D.A.

1980-01-01

Water-quality data collected in the upper Oyster Creek drainage basin, Ocean County, N.J., indicate that the stream has excellent water quality except for a persistently low pH. The mean concentrations of the major inorganic ions were all less than 6.0 milligrams per liter. Mean concentrations of total nitrogen and total phosphorus were 0.15 mg/L and 0.01 mg/L, respectively. Dissolved oxygen averaged 8.7 mg/L and 81% saturation. Low pH levels are typical of streams draining cedar swamps. In Oyster Creek, the pH tended to decrease downstream due to chemical and biological processes. The pH levels in swamps were one-half unit or more lower than the pH levels in the adjacent stream. Sharp declines in stream pH were noted during runoff periods as the result of the mixing of poorly-buffered stream water with more highly acidic water from surrounding swamp areas. The quality of ground water within the study area was similar to the quality of streamflow, except for higher iron and ammonia-nitrogen concentrations and a higher pH range of 4.9 to 6.5. Precipitation represented a major source of many chemical constituents in the ground- and surface-waters of the Oyster Creek basin. (USGS)

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. © 2015 Society for Conservation Biology.

Geologic controls on the recent evolution of oyster reefs in Apalachicola Bay and St. George Sound, Florida

USGS Publications Warehouse

Twichell, D.; Edmiston, L.; Andrews, Brian; Stevenson, W.; Donoghue, J.; Poore, Richard; Osterman, Lisa E.

2010-01-01

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.

A conserved tad pilus promotes Vibrio vulnificus oyster colonization.

PubMed

Pu, Meng; Duriez, Patrick; Arazi, Mattan; Rowe-Magnus, Dean A

2018-02-01

Vibrio vulnificus has the highest death rate (>35%) and per-case economic burden ($3.3 million) of any foodborne pathogen in the United States. Infections occur via open wounds or following ingestion of contaminated seafood, most infamously oysters. We isolated a 1000th generation descendant, designated NT that exhibited increased biofilm and aggregate formation relative to its parent. We identified two significant causal changes underlying these phenotypes. First, the entire 24-kb capsular polysaccharide biosynthesis locus, which is essential for virulence but inhibits biofilm formation, had been purged from the genome. However, NT formed more extensive biofilms and aggregates than a defined cps mutant, suggesting that additional factor(s) contributed to its phenotypes. Second, the expression of a tight adherence (tad) pilus locus was elevated in NT. Deletion of the associated pilin (flp) decreased NT biofilm and aggregate formation. Furthermore, NTΔflp strains were deficient relative to NT in an oyster colonization model, demonstrating a positive correlation between the biofilm and aggregation phenotypes associated with Tad pilus production and efficient bacterial retention by feeding oysters. Despite being widely distributed in the Vibrionaceae, this is the first demonstration of a bona fide physiological role for a Tad pilus in this bacterial family. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Transmission of the haplosporidian parasite MSX Haplosporidium nelsoni to the eastern oyster Crassostrea virginica in an upweller system.

PubMed

Sunila, I; Karolus, J; Lang, E P; Mroczka, M E; Volk, J

2000-08-31

The haplosporidian oyster parasite MSX (Multinucleated Sphere X) Haplosporidium nelsoni was transmitted to eastern oysters Crassostrea virginica. Hatchery-raised, MSX-free juvenile oysters were placed in upweller tanks. Water to the tanks was filtered through a screen with 1 mm2 openings and originated from the water column overlaying naturally infected oysters beds (MSX prevalence 17 to 57%). MSX was diagnosed by histopathological analysis. MSX-disease (57% prevalence) with increased mortality (19%) was observed 11 wk after the beginning of the exposure and mortality of 80% after 16 wk. The study demonstrates transmission of MSX via water-borne infectious agents capable of passing through a 1 mm filter.

Vulnerability of Oyster Resource Users to Ecological Change: Case Study from Terrebonne Parish, Louisiana

NASA Astrophysics Data System (ADS)

Humphries, A.; La Peyre, M.; Hall, S.; Dowty Beech, R.

2016-02-01

Knowledge of vulnerability provides the foundation for developing actions that minimize impacts on people while maximizing the sustainability of ecosystem goods and services including fisheries. As a result, it is becoming increasingly important to determine if resource-dependent people are vulnerable to ecological change as anthropogenic and climate-induced stressors affect resources in different ways. In coastal Louisiana, the current era of rapid marsh loss and abrupt environmental variation (e.g., sediment diversions) has the potential to undermine oyster-associated livelihoods for those most vulnerable. To evaluate vulnerability, we examined dimensions of social sensitivity and adaptive capacity using semi-structured interviews with three stakeholder groups in the oyster fishery of Terrebonne Parish, Louisiana. Results indicate that oyster owners/operators are highly dependent, and thus sensitive, to changes in the ecological conditions of the fishery due to high levels of occupational identity; however they are likely adaptable, reflected in their willingness to learn about new practices and evolve over time. In contrast, oyster fishers that do not own any portion of the business in which they operate are bad at coping with change and frequently hold negative or fatalistic views on financial planning. Overall, oyster resource users most vulnerable to ecological change will be those with high levels of stewardship, open-minded values, and a balanced perception of environment, as well as low to moderate levels of personal and financial buffers and trust. These results suggest that resource users with higher sensitivity to change are not necessarily most vulnerable because sensitivity may be offset by adaptive capacity. In other words, while sensitivity may determine the potential impact of a climate- or human-induced ecological change to the oyster fishery, adaptive capacity can be a major influence on what impacts actually eventuate.

Impact of pCO2 on the energy, reproduction and growth of the shell of the pearl oyster Pinctada margaritifera

NASA Astrophysics Data System (ADS)

Le Moullac, G.; Soyez, C.; Vidal-Dupiol, J.; Belliard, C.; Fievet, J.; Sham-Koua, M.; Lo-Yat, A.; Saulnier, D.; Gaertner-Mazouni, N.; Gueguen, Y.

2016-12-01

The possible consequences of acidification on pearl farming are disruption of oyster metabolism and change in growth. In the laboratory, we studied the impact of pCO2 (3540, 1338 and 541 μatm) on the physiology of pearl oysters exposed for 100 days. This experiment was repeated after an interval of one year. Several physiological compartments were examined in pearl oysters: the scope for growth by measuring ingestion, assimilation and oxygen consumption, gametogenesis by means of histological observations, shell growth by measurement and observation by optical and electronic microscopy, and at molecular level by measuring the expression of nine genes of mantle cells implied in the biomineralisation process. Results from both experiments showed that high pCO2 had no effect on scope for growth and gametogenesis. High pCO2 (3540 μatm) significantly slowed down the shell deposit rate at the ventral side and SEM observations of the inside of the shell found signs of chemical dissolution. Of the nine examined genes high pCO2significantly decreased the expression level of one gene (Pmarg-PUSP 6). This study showed that shell growth of the pearl oyster would be slowed down without threatening the species since the management of energy and reproduction functions appeared to be preserved. Further investigations should be conducted on the response of offspring to acidification.

Interior of the shipping room with doorway leading to processing ...

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

Interior of the shipping room with doorway leading to processing room. A pass-through window with conveyor allowed the fresh packed oysters to be sent from the processing room into the shipping room. - J.C. Lore Oyster House, 14430 Solomons Island Road, Solomons, Calvert County, MD

Developing methods for assessing abundance and distribution of European oysters (Ostrea edulis) using towed video.

PubMed

Thorngren, Linnea; Dunér Holthuis, Thomas; Lindegarth, Susanne; Lindegarth, Mats

2017-01-01

Due to large-scale habitat losses and increasing pressures, benthic habitats in general, and perhaps oyster beds in particular, are commonly in decline and severely threatened on regional and global scales. Appropriate and cost-efficient methods for mapping and monitoring of the distribution, abundance and quality of remaining oyster populations are fundamental for sustainable management and conservation of these habitats and their associated values. Towed video has emerged as a promising method for surveying benthic communities in a both non-destructive and cost-efficient way. Here we examine its use as a tool for quantification and monitoring of oyster populations by (i) analysing how well abundances can be estimated and how living Ostrea edulis individuals can be distinguished from dead ones, (ii) estimating the variability within and among observers as well as the spatial variability at a number of scales, and finally (iii) evaluating the precision of estimated abundances under different scenarios for monitoring. Overall, the results show that the can be used to quantify abundance and occurrence of Ostrea edulis in heterogeneous environments. There was a strong correlation between abundances determined in the field and abundances estimated by video-analyses (r2 = 0.93), even though video analyses underestimated the total abundance of living oysters by 20%. Additionally, the method was largely repeatable within and among observers and revealed no evident bias in identification of living and dead oysters. We also concluded that the spatial variability was an order of magnitude larger than that due to observer errors. Subsequent modelling of precision showed that the total area sampled was the main determinant of precision and provided general method for determining precision. This study provides a thorough validation of the application of towed video on quantitative estimations of live oysters. The results suggest that the method can indeed be very useful for

Developing methods for assessing abundance and distribution of European oysters (Ostrea edulis) using towed video

PubMed Central

Dunér Holthuis, Thomas; Lindegarth, Susanne; Lindegarth, Mats

2017-01-01

Due to large-scale habitat losses and increasing pressures, benthic habitats in general, and perhaps oyster beds in particular, are commonly in decline and severely threatened on regional and global scales. Appropriate and cost-efficient methods for mapping and monitoring of the distribution, abundance and quality of remaining oyster populations are fundamental for sustainable management and conservation of these habitats and their associated values. Towed video has emerged as a promising method for surveying benthic communities in a both non-destructive and cost-efficient way. Here we examine its use as a tool for quantification and monitoring of oyster populations by (i) analysing how well abundances can be estimated and how living Ostrea edulis individuals can be distinguished from dead ones, (ii) estimating the variability within and among observers as well as the spatial variability at a number of scales, and finally (iii) evaluating the precision of estimated abundances under different scenarios for monitoring. Overall, the results show that the can be used to quantify abundance and occurrence of Ostrea edulis in heterogeneous environments. There was a strong correlation between abundances determined in the field and abundances estimated by video-analyses (r2 = 0.93), even though video analyses underestimated the total abundance of living oysters by 20%. Additionally, the method was largely repeatable within and among observers and revealed no evident bias in identification of living and dead oysters. We also concluded that the spatial variability was an order of magnitude larger than that due to observer errors. Subsequent modelling of precision showed that the total area sampled was the main determinant of precision and provided general method for determining precision. This study provides a thorough validation of the application of towed video on quantitative estimations of live oysters. The results suggest that the method can indeed be very useful for

Plugging the leak: barrier island restoration following Hurricane Katrina enhances larval retention and improves salinity regime for oysters in Mobile Bay, Alabama.

PubMed

Park, Kyeong; Powers, Sean P; Bosarge, George S; Jung, Hoon-Shin

2014-03-01

Changes in geomorphology of estuaries are common following major perpetuations such as hurricanes and may have profound impacts on biological systems. Hurricane Katrina in 2005 created a new pass, called Katrina Cut, halving Dauphin Island in Mobile Bay, Alabama. Significant decline in oyster population at Cedar Point Reef, the primary oyster harvest grounds in Mobile Bay, had persisted since then until the Cut was artificially closed in 2010. A bio-physical model for hydrodynamics and oyster larval transport was used to evaluate two potential mechanisms responsible for oyster population declines: salinity changes in the context of oyster habitat suitability and retention of oyster larvae. The model results revealed that when open Katrina Cut increased salinity at Cedar Point Reef. During high freshwater discharge, in particular, water exchange through Katrina Cut increased the bottom salinity from <5 psu to well over 15 (sometimes >20) psu during the tropic tides. Elevated salinities are associated with greater predation on oysters and higher disease incidence. The presence of the Katrina Cut also reduced larval retention in the spawning area regardless of tidal or river discharge conditions. We conclude that closing the Cut likely improved conditions for oysters within Mobile Bay and eastern Mississippi Sound and that these improved conditions have contributed to increased oyster landings. Copyright © 2013 Elsevier Ltd. All rights reserved.

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...

An outbreak of viral gastroenteritis associated with adequately prepared oysters.

PubMed Central

Chalmers, J. W.; McMillan, J. H.

1995-01-01

Over Christmas 1993, an outbreak of food poisoning occurred among guests in a hotel in South West Scotland. Evidence from a cohort study strongly suggested that raw oysters were the vehicle for infection, probably due to a Small Round Structured Virus (SRSV). Detailed enquiry about the source and preparation of the oysters revealed no evidence of any unsafe handling at any stage in the food chain, nor any evidence of bacterial contamination. It is suggested that the present standards of preparation and monitoring are inadequate to protect the consumer, and that bacteriophage monitoring may be a useful method of screening for viral contamination in future. PMID:7641830

Oyster reef restoration supports increased nekton biomass and potential commercial fishery value

PubMed Central

2015-01-01

Across the globe, discussions centered on the value of nature drive many conservation and restoration decisions. As a result, justification for management activities increasingly asks for two lines of evidence: (1) biological proof of augmented ecosystem function or service, and (2) monetary valuation of these services. For oyster reefs, which have seen significant global declines and increasing restoration work, the need to provide both biological and monetary evidence of reef services on a local-level has become more critical in a time of declining resources. Here, we quantified species biomass and potential commercial value of nekton collected from restored oyster (Crassostrea virginica) reefs in coastal Louisiana over a 3-year period, providing multiple snapshots of biomass support over time. Overall, and with little change over time, fish and invertebrate biomass is 212% greater at restored oyster reefs than mud-bottom, or 0.12 kg m−2. The additional biomass of commercial species is equivalent to an increase of local fisheries value by 226%, or $0.09 m−2. Understanding the ecosystem value of restoration projects, and how they interact with regional management priorities, is critical to inform local decision-making and provide testable predictions. Quantitative estimates of potential commercial fisheries enhancement by oyster reef restoration such as this one can be used directly by local managers to determine the expected return on investment. PMID:26336635

Oyster reef restoration supports increased nekton biomass and potential commercial fishery value

USGS Publications Warehouse

Humphries, Austin T.; LaPeyre, Megan K.

2015-01-01

Across the globe, discussions centered on the value of nature drive many conservation and restoration decisions. As a result, justification for management activities increasingly asks for two lines of evidence: (1) biological proof of augmented ecosystem function or service, and (2) monetary valuation of these services. For oyster reefs, which have seen significant global declines and increasing restoration work, the need to provide both biological and monetary evidence of reef services on a local-level has become more critical in a time of declining resources. Here, we quantified species biomass and potential commercial value of nekton collected from restored oyster (Crassostrea virginica) reefs in coastal Louisiana over a 3-year period, providing multiple snapshots of biomass support over time. Overall, and with little change over time, fish and invertebrate biomass is 212% greater at restored oyster reefs than mud-bottom, or 0.12 kg m−2. The additional biomass of commercial species is equivalent to an increase of local fisheries value by 226%, or $0.09 m−2. Understanding the ecosystem value of restoration projects, and how they interact with regional management priorities, is critical to inform local decision-making and provide testable predictions. Quantitative estimates of potential commercial fisheries enhancement by oyster reef restoration such as this one can be used directly by local managers to determine the expected return on investment.

Growth and survival of host pearl oyster Pinctada fucata martensii (Dunker, 1880) treated by different biofouling-clean methods in China

NASA Astrophysics Data System (ADS)

Li, Junhui; Yang, Chuangye; Wang, Qingheng; Du, Xiaodong; Deng, Yuewen

2018-07-01

Pearl oyster Pinctada fucata martensii is an economically important species farmed to produce round nucleated pearl in China. However, pearl oyster shells are commonly exposed to biofouling, which is manually cleaned. This study experimentally evaluates the effects of biofouling cleaning by Siganus fuscescens (Houttuyn, 1782) foraging on growth performance and pearl traits of host pearl oyster P. fucata martensii. Three groups designated as EG1, EG2 and EG3 were set in the experiment. In EG1, biofouling was manually cleaned every 2 weeks and oysters were cultured in natural sea conditions. In EG2, biofouling was cleaned by foraging behavior of S. fuscescens every 2 weeks and oysters were cultured in natural sea conditions. In EG3, oysters were farmed in the net cage where S. fuscescens were stored. The survival rate of EG2 was higher than those of EG1 and EG3 and the daily growth rates of length and weight of shell and the thickness and weight of pearl of EG3 were significantly larger than those of EG1 and EG2. The survival rate, daily growth rates of the length and weight of shell, and thickness and weight of pearl were not significantly different between EG1 and EG2. This study suggested S. fuscescens foraging could evidently improve survival of host pearl oyster, which is promising to improve pearl yield in pearl oyster farms in China.

Effects of Dry Storage and Resubmersion of Oysters on Total Vibrio vulnificus and Total and Pathogenic (tdh+/trh+) Vibrio parahaemolyticus Levels.

PubMed

Kinsey, Thomas P; Lydon, Keri A; Bowers, John C; Jones, Jessica L

2015-08-01

Vibrio vulnificus (Vv) and Vibrio parahaemolyticus (Vp) are the two leading causes of bacterial illnesses associated with raw shellfish consumption. Levels of these pathogens in oysters can increase during routine antifouling aquaculture practices involving dry storage in ambient air conditions. After storage, common practice is to resubmerge these stored oysters to reduce elevated Vv and Vp levels, but evidence proving the effectiveness of this practice is lacking. This study examined the changes in Vv and in total and pathogenic (thermostable direct hemolysin gene and the tdh-related hemolysin gene, tdh+ and trh+) Vp levels in oysters after 5 or 24 h of dry storage (28 to 32°C), followed by resubmersion (27 to 32°C) for 14 days. For each trial, replicate oyster samples were collected at initial harvest, after dry storage, after 7 days, and after 14 days of resubmersion. Oysters not subjected to dry storage were collected and analyzed to determine natural undisturbed vibrio levels (background control). Vibrio levels were measured using a most-probable-number enrichment followed by real-time PCR. After storage, vibrio levels (excluding tdh+ and trh+ Vp during 5-h storage) increased significantly (P < 0.001) from initial levels. After 7 days of resubmersion, Vv and total Vp levels (excluding total Vp in oysters stored for 5 h) were not significantly different (P < 0.1) from levels in background oysters. Vv and total and pathogenic Vp levels were not significantly different (P > 0.1) from levels in background oysters after 14 days of resubmersion, regardless of dry storage time. These data demonstrate that oyster resubmersion after dry storage at elevated ambient temperatures allows vibrio levels to return to those of background control samples. These results can be used to help minimize the risk of Vv and Vp illnesses and to inform the oyster industry on the effectiveness of routine storing and resubmerging of aquaculture oysters.

The Mendelian inheritance of rare flesh and shell colour variants in the black-lipped pearl oyster (Pinctada margaritifera).

PubMed

Ky, Chin-Long; Nakasai, Seiji; Pommier, Steve; Sham Koua, Manaarii; Devaux, Dominique

2016-10-01

Pinctada margaritifera is French Polynesia's most economically important aquaculture species. This pearl oyster has the specific ability to produce cultured pearls with a very wide range of colours, depending on the colour phenotypes of donor oysters used. Its aquaculture is still based on natural spat collection from wild stocks. We investigated three rare colour variants of P. margaritifera - orange flesh, and red and white shell colour phenotypes - in comparison with the wild-type black flesh and shell commonly found in this species. The study aimed to assess the geographic distribution and genetic basis of these colour variants. Colour frequencies were evaluated during transfer and graft processes of pearl oyster seed captured at collector stations. Among the collection locations studied, Mangareva Island showed the highest rate of the orange flesh phenotype, whereas Takaroa and Takume atolls had relatively high rates of red and white shell phenotypes respectively. Broodstocks were made of these rare colour variants, and crosses were performed to produce first- and second-generation progenies to investigate segregation. The results were consistent with Mendelian ratios and suggest a distinct model with no co-dominance: (i) a two-allele model for flesh trait, whereby the orange allele is recessive to the black fleshed type, and (ii) a three-allele model for shell trait, whereby the black wild-type allele is dominant to the red coloration, which is dominant to the white shell. Furthermore, the proposed model provides the basis for producing selected donor pearl oyster lines through hatchery propagation. © 2016 Stichting International Foundation for Animal Genetics.

Assessment of sediment contamination by spermiotoxicity and embryotoxicity bioassays with sea urchins (Paracentrotus lividus) and oysters (Crassostrea gigas).

PubMed

Geffard, O; Budzinski, H; Augagneur, S; Seaman, M N; His, E

2001-07-01

Gametes (sperm) and fertilized eggs (embryos) of the Mediterranean sea urchin, Paracentrotus lividus, and the Japanese oyster, Crassostrea gigas, were used to investigate the toxicity of two marine sediments, one polluted by polycyclic aromatic hydrocarbons (PAH) and the other by heavy metals. The sediment samples were freeze-dried for storage, and three different treatments were used for analysis: whole sediment, unfiltered elutriate, and filtered elutriate. The two sediments were toxic to sea urchin spermatozoa but not to oyster spermatozoa, and embryotoxicity was almost always the more sensitive endpoint for toxicity assessment. As a rule, whole sediment was more toxic than the elutriates by nearly two orders of magnitude. With respect to embryotoxicity, the whole sediments and the elutriates of the PAH-contaminated sediment were more toxic to oyster embryos, whereas the elutriates of the sediment polluted by heavy metals had stronger effects on sea urchin embryos. The results confirm that bioassays with Japanese oyster embryos provide a more sensitive appraisal of toxicity in the marine environment than bioassays with other developmental stages. As a whole, Mediterranean sea urchins and Japanese oysters were similar in overall sensitivity and are therefore both equally suited as bioassay organisms, but tests with oysters are more reproducible because of the better performance of the controls.

Growth, morphometrics and nutrient content of farmed eastern oysters, Crassostrea virginica (Gmelin), in New Hampshire, USA

EPA Science Inventory

When harvested, oysters represent a removal from the ecosystem of nutrients such as nitrogen (N)and carbon (C). A number of factors potentially affect nutrient content, but a quantitative understanding across the geographical range of the eastern oysters is lacking. This study wa...

Inactivation of Vibrio parahaemolyticus and Vibrio vulnificus in oysters by high-hydrostatic pressure and mild heat.

PubMed

Ye, Mu; Huang, Yaoxin; Chen, Haiqiang

2012-10-01

Several recent outbreaks associated with oysters have heightened safety concerns of raw shellfish consumptions, with the majority being attributed to Vibrio spp. The objective of this study was to determine the effect of high-hydrostatic pressure (HHP) followed by mild heating on the inactivation of Vibrio parahaemolyticus and Vibrio vulnificus in live oysters. Inoculated oysters were randomly subjected to: a) pressurization at 200-300 MPa for 2 min at 21 °C, b) mild heat treatment at 40, 45 or 50 °C for up to 20 min and c) pressure treatment of 200-300 MPa for 2 min at 21 °C followed by heat treatment at 40-50 °C. Counts of V. parahaemolyticus and V. vulnificus were then determined using the most probable number (MPN) method. Pressurization at 200-300 MPa for 2 min resulted in various degrees of inactivation, from 1.2 to >7 log MPN/g reductions. Heat treatment at 40 and 45 °C for 20 min only reduced V. parahaemolyticus and V. vulnificus by 0.7-2.5 log MPN/g while at 50 °C for 15 min achieved >7 log MPN/g reduction. HHP and mild heat had synergistic effects. Combinations such as HHP at 250 MPa for 2 min followed by heat treatment at 45 °C for 15 min and HHP at 200 MPa for 2 min followed by heat treatment at 50 °C for 5 min reduced both V. parahaemolyticus and V. vulnificus to non-detectable levels by the MPN method (<3 MPN/g). HHP at ≥275 MPa for 2 min followed by heat treatment at 45 °C for 20 min and HHP at ≥200 MPa for 2 min followed by heat treatment at 50 °C for 15 min completely eliminated both pathogens in oysters (negative enrichment results). This study demonstrated the efficiency of HHP followed by mild heat treatments on inactivation of V. parahaemolyticus and V. vulnificus and could help the industry to establish parameters for processing oysters. Copyright © 2012 Elsevier Ltd. All rights reserved.

[The composition of volatile components of cepe (Boletus edulis) and oyster mushrooms (Pleurotus ostreatus)].

PubMed