Prevalence of Microplastics in the Eastern Oyster Crassostrea virginica in the Chesapeake Bay: The Impact of Different Digestion Methods on Microplastic Properties

This study aimed to determine the microplastic prevalence in eastern oysters (C. virginica) in three sites in the Chesapeake Bay in Virginia and optimize the digestion methods. The digestion results illustrate that the lowest recovery rate and digestion recovery were related to enzymatic, enzymatic + hydrogen peroxide (H2O2), and HCl 5% treatments, while the highest digestion recovery and recovery rate were observed in H2O2 and basic (KOH) treatments. Nitric acid digestion resulted in satisfying digestion recovery (100%), while no blue polyethylene microplastics were observed due to the poor recovery rate. In addition, nitric acid altered the color, changed the Raman spectrum intensity, and melted polypropylene (PP) and polyethylene terephthalate (PET). In order to determine the number of microplastics, 144 oysters with an approximately similar size and weight from three sites, including the James River, York River, and Eastern Shore, were evaluated. Fragments were the most abundant microplastics among the different microplastics, followed by fibers and beads, in the three sites. A significantly higher number of fragments were found in the James River, probably due to the greater amount of human activities. The number of microplastics per gram of oyster tissue was higher in the James River, with 7 MPs/g tissue, than in the York River and Eastern Shore, with 6.7 and 5.6 MPs/g tissue.

Oyster heat shock protein 70 plays a role in binding of human noroviruses

Human noroviruses (HuNoVs) are important foodborne pathogens causing acute gastroenteritis. Oysters are an important vehicle for transmission of HuNoVs. Histo-blood group antigen (HBGA)-like substances are considered the primary ligands for bioaccumulation of HuNoVs in oyster tissues. In this study, proteinaceous ligands for specific binding of HuNoVs were mined from oyster tissues using a bacterial cell surface display system. The macromolecular target was captured and identified in proteomic analysis. The distribution of viral particles, oyster heat shock protein 70 (oHSP 70), and type A HBGA (positive control) in oyster tissue was investigated by multiplex immunofluorescence assays after artificial contamination with HuNoVs (GII.4). Our results demonstrated that oHSP 70 is a candidate vital ligand for specific binding of HuNoVs in oyster tissues. In addition, P proteins (GI.1 and GII.4) and viral particles (GI.1 and GII.4) were captured by recombinant oHSP 70 in an enzyme-linked immunosorbent assay with sample signal/negative signal of 7.8, 6.3, 17.0, and 8.8, respectively. The findings suggested that oHSP 70 plays an important role in the binding of these foodborne viruses. Importance Human noroviruses (HuNoVs) are the most important pathogen for non-bacterial epidemic gastroenteritis cases. Foodborne transmission plays an important role in HuNoVs infection. Oysters, filter-feeding epibenthic bivalves, can be contaminated by faecal discharge in harvest water. A new proteinaceous ligand for HuNoVs other than HBGA is identified in oyster tissues. The significance of our research is in identifying and verifying the ligands in oyster tissues for HuNoVs binding. Our data will allow a better understanding of HuNoVs attachment and transmission with oysters, leading to control of undesired foodborne disease.

Effects of Extraction Buffer on the Solubility and Immunoreactivity of the Pacific Oyster Allergens

Despite recent technological advances, novel allergenic protein discovery is limited by their low abundance, often due to specific physical characteristics restricting their recovery during the extraction process from various allergen sources. In this study, eight different extraction buffers were compared for their ability to recover proteins from Pacific oyster (Crassostrea gigas). The protein composition was investigated using high resolution mass spectrometry. The antibody IgE-reactivity of each extract was determined using a pool of serum from five shellfish-allergic patients. Most of the investigated buffers showed good capacity to extract proteins from the Pacific oyster. In general, a higher concentration of proteins was recovered using high salt buffers or high pH buffers, subsequently revealing more IgE-reactive bands on immunoblotting. In contrast, low pH buffers resulted in a poor protein recovery and reduced IgE-reactivity. Discovery of additional IgE-reactive proteins in high salt buffers or high pH buffers was associated with an increase in allergen abundance in the extracts. In conclusion, increasing the ionic strength and pH of the buffer improves the solubility of allergenic proteins during the extraction process for oyster tissue. This strategy could also be applied for other difficult-to-extract allergen sources, thereby yielding an improved allergen panel for increased diagnostic efficiency.

Organic Pollutants along the Qatari Coast: A Case Study of the Pearl Oyster (Pinctada radiata)

The Qatari marine environment is endangered due to high industrial expansion and anthropogenic pressure over the last few decades. The presence of common contaminants such as total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs) is a threat to the marine environment. The aim of this study is to determine the environmental threats and risks posed by organic contaminants to Qatar’s marine environment using pearl oyster ‘Pinctada Radiata’ as the indicator study organism. The samples (marine sediment, seawater, and oysters) were collected four times within two years in different seasons from the four sites (Simaisma, Al Khor, Umm Bab, and Al Wakra), on March 2017, December 2017, May 2018, and November 2018. A total of 144 samples were analyzed, 48 samples of seawater, 48 samples of sediment and 48 samples of oysters. Levels of organic contaminants (TPHs and PAHs) were quantified in seawater, marine sediment and oyster tissues (P. radiata). In addition, the TOC and particle sizes were measured in abiotic matrices as well as the temperature, salinity, and pH of seawater in the study areas. Overall, the organic contaminants (TPHs and PAHs) were more readily detected in oyster tissue samples than marine sediment and seawater samples collected from the same areas. The surface seawater samples showed negligible levels of PAHs, while TPHs were ranged from 1.164 to 271.77 μg/L. The concentration of TPHs and PAHs in surface marine sediment were ranged between (75.02 -1751.82) and (4.25 - 36.73) μg/kg dry weight respectively. In oyster tissue samples, the level of TPHs was ranged from 633.33 to 6666.67 μg/kg dry weight, with the highest concentrations measured in Simaisma, while PAHs concentration showed an extreme variation from 25.90 to 2244.03μg/kg dry weight. The present study could, however, provide useful background information for further investigations to understand the presence of organic contaminants in Qatar’s marine environment.

Assessment of Nine Micronutrients in Jasmine 85 Rice Grown in Ghana Using Neutron Activation Analysis

The amount of micronutrients in food is a key factor that determines the health status of a person. The concentrations of nine micronutrients, Sodium (Na), Magnesium (Mg), Chlorine (Cl), Potassium (K), Calcium (Ca), Vanadium (V), Manganese (Mn), Copper (Cu) and Iodine (I), in polished Jasmine 85 rice, locally cultivated in five rice farming areas in Ghana (Afienya, Afife, Dawhenya, Ashaiman and Aveyime), were determined using Neutron Activation Analysis. The standard materials used as reference were the International Atomic Energy Agency (IAEA)-530 Tuna fish homogenate and the National Institute of Standard and Technology (NIST) USA 1566b Oyster Tissue. Recoveries of the elemental concentrations ranged from 88% to 111% of the certified values. Relative standardization method was used in the quantification of the elements. The range of concentrations measured in the rice are: 142.3-188.1 mg/kg for Na, 483.2-875.7 mg/kg for Mg, 465.6-718.0 mg/kg for Cl, 514.6-2949.0 mg/kg for K, 2303.0-2622.0 mg/kg for Ca, 0.0698-0.1925 mg/kg for V, 9.956-14.460 mg/kg for Mn, 0.8728-1.6790 mg/kg for Cu and 0.1181-0.1447 mg/kg for I. Using Hierarchical clustering analysis and Principal Component Analysis to evaluate the intensities of measured concentrations, K was established to be the most abundant, and was used to categorize two distinct clusters; Group 1 farms (Ashaiman, Afienya, and Dawhenya) and Group 2 farms (Aveyime and Afife). Group 2 farms recorded elevated intensities of micronutrients. With Pearson's correlation coefficient, some noteworthy correlations realized were between Na and K (r = 0.951), Na and V (r = 0.842) and K and V (r = 0.812). This indicated the same or similar source inputs for each pair. The calculated mean daily intake of K exceeded the mean Recommended Dietary Allowable and Adequate Intake for all Life Stage Groups. Estimated health risk associated with the consumption of rice was only present for children between the ages of 1 and 3 for Mg. The information on these nine micronutrients content of the rice from these five farming areas would be valuable in rice consumption studies to evaluate the overall availability of micronutrients to the Ghanaian populace and age groups and also in nutrition planning for analysis of nationwide rice supplies, mainly for regions and countries known to be susceptible to deficiencies of these micronutrients. The techniques espoused in this research can be used to accurately determine the concentration of micronutrients in rice and also trace the area where the rice was produced.

Enumeration and Survival of Salmonella enterica in Live Oyster Shellstock Harvested from Canadian Waters

ABSTRACT Since 2015, 11 recalls of live oyster shellstock have been issued in Canada due to the presence of Salmonella enterica. Six of those recalls took place in 2018. To understand this increase, fundamental information is needed on the relationship between S. enterica and oysters. The aims of this study were to address important data gaps concerning the levels of Salmonella in naturally contaminated oysters and the ability of this pathogen to survive in live oyster shellstock. Enumeration data were evaluated for five oyster and clam samples collected from the east coast of Canada from 2015 to 2018. The reported levels were <0.0015 to 0.064 most probable number per g of oyster tissue. The S. enterica isolates recovered from these animals belonged to serovars Typhimurium, Infantis, Enteritidis, and I 4,5:i:−. Filter feeding by the oysters was exploited to assess the Salmonella accumulation that would occur following a natural contamination event. Detectable levels of the pathogen were observed after 30 min of exposure and began to plateau at 60 min. A survival study in live oyster shellstock indicated that after 4 days of storage at ambient temperatures, the Salmonella level declined slightly from 4.3 to 3.7 log CFU/g. These data indicate that the levels of Salmonella found in naturally contaminated oysters are low and are not expected to increase between the point of harvest and the point of consumption. The changing ecology of shellfish environments requires continued monitoring and testing to safeguard public health. The data presented here will be useful for the evaluation and design of sampling plans and risk management approaches for the control of Salmonella in live oyster shellstock. HIGHLIGHTS

Carbon Isotopes (δ13C and Δ14C) in Shell Carbonate, Conchiolin, and Soft Tissues in Eastern Oyster (Crassostrea Virginica)

Biogeochemical analyses of eastern oysters (Crassostrea virginica) are frequently included in environmental monitoring and paleoecological studies because their shells and soft tissues record environmental and dietary signals. Carbon isotopes in the mineral phase of the shell are derived from ambient bicarbonate and dissolved inorganic carbon (DIC), while organic carbon present in soft tissue is of dietary origin. Mineral-bound organic matter within the carbonate shell matrix (“conchiolin”) is studied less frequently. The purpose of this study was to compare carbon isotope composition (δ13C and Δ14C) of conchiolin to those of shell carbonates and soft tissues in eastern oysters and assess the extent to which conchiolin can provide insight into paleoecological records. Eleven oyster specimens were live-collected from Apalachicola Bay, USA, as well as a set of environmental samples (water, sediment, and terrestrial plants). Overall, the δ13C values in all studied oyster tissue types record environmental signals related to carbon sources, with conchiolin being enriched in 13C by an average of 2.3‰ relative to bulk soft tissues. Δ14C values in oyster shell carbonates generally reflect the marine versus riverine source of DIC, while conchiolin Δ14C values are impacted by variable relative contributions of young and old organic matter. Environmental samples indicate a significantly large difference in Δ14C among sources, from –127‰ in particulate organic matter to approximately +15‰ in DIC. Conchiolin is significantly depleted in 14C relative to other tissue types, by as much as 56.6‰, posing a major obstacle to the use of conchiolin as an alternative material for radiocarbon dating.