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Eastern oysters (Crassostrea virginica) from three locations along the Delaware Bay were surveyed monthly from May to October 2017 for levels of total Vibrio parahaemolyticus, pathogenic strains of V. parahaemolyticus and Vibrio vulnificus, and for strain-specific bacteriophages against vibrios (vibriophages). The objectives were to determine (a) whether vibriophages against known strains or serotypes of clinical and environmental vibrios were detectable in oysters from the Delaware Bay and (b) whether vibriophage presence or absence corresponded with Vibrio abundances in oysters. Host cells for phage assays included pathogenic V. parahaemolyticus serotypes O3:K6, O1:KUT (untypable) and O1:K1, as well as clinical and environmental strains of V. vulnificus. Vibriophages against some, but not all, pathogenic V. parahaemolyticus serotypes were readily detected in Delaware Bay oysters. In July, abundances of total and pathogenic V. parahaemolyticus at one site spiked to levels exceeding regulatory guidelines. Phages against three V. parahaemolyticus host serotypes were detected in these same oysters, but also in oysters with low V. parahaemolyticus levels. Serotype-specific vibriophage presence or absence did not correspond with abundances of total or pathogenic V. parahaemolyticus. Vibriophages were not detected against three V. vulnificus host strains, even though V. vulnificus were readily detectable in oyster tissues. Selected phage isolates against V. parahaemolyticus showed high host specificity. Transmission electron micrographs revealed that most isolates were ~ 60-nm diameter, non-tailed phages. In conclusion, vibriophages were detected against pandemic V. parahaemolyticus O3:K6 and O1:KUT, suggesting that phage monitoring in specific host cells may be a useful technique to assess public health risks from oyster consumption.

This research focuses on the efficiency of recommended heavy use area protection (HUAP) pads installed in poultry houses utilizing the Choptank River, a tributary of the Chesapeake Bay. The Chesapeake Bay watershed is severely affected by crop agriculture and poultry feeding operations. Water quality degradation along with scarcity of water is a significant concern in this area, suggesting a need for changes in both environmental and groundwater management practices. Our objective in this study was to compare the efficiency of HUAP in reducing litter spillage and nutrient runoff between two poultry houses, one of which was constructed in 2005 and the other in 2009. The poultry house constructed in 2005 did not have HUAP pads initially, they were built in 2006. The poultry house built in 2009 had the pads from the starting point. We collected soil and water samples each month and analyzed them for pH, electrical conductivity (EC), nitrate, nitrite, total nitrogen, phosphate, and other soil properties throughout the year. The pH of soil and water samples was in the range of 6.8–8.0 and 6.5–7.2, respectively. We collected six water samples in total in the ditch, from points at retention ponds near the farm ditch to sites in wooded areas on the farm. Water sample B (where ditch water meets retention pond water from the poultry farm) had the highest EC value and nitrate, nitrite, and total nitrogen concentrations compared with other water samples. The subsequent water samples downstream had reduced loads of nutrients. The study results suggest that there was a minimum carryover of nutrients from soil into the runoff water, storm ditches, and adjacent stream. There was also a minimal effect of house cleaning and storm events in raising the concentration of nutrients in soil and water samples at our study sites. The older poultry site had higher total nitrogen and phosphorous surrounding the pads, whereas no elevated levels of nutrients were identified at the newer site. The ability of HUAP pads to hold onto contaminates decreases with age and use. This study also shows that the impacts from poultry activities on surface and groundwater can be minimized by using management practices such as HUAP pads. These practices can reduce pollution in the farm, increase productivity, and save farmers and ranchers time and money in the long run.

This study identifiedVibrio parahaemolyticusin oyster and seawater samples collected from Delaware Bay from June through October of 2016. Environmental parameters including water temperature, salinity, dissolved oxygen, pH, and chlorophyllawere measured per sampling event. Oysters homogenate and seawater samples were 10-fold serially diluted and directly plated on CHROMagarᵀᴹ Vibrio medium. PresumptiveV.parahaemolyticuscolonies were counted and at least 20% of these colonies were selected for molecular chracterization.V.parahaemolyticusisolates (n = 165) were screened for the presence of the species-specific thermolabile hemolysin (tlh) gene, the pathogenic thermostable direct hemolysin (tdh)/ thermostable related hemolysin (trh) genes, the regulatory transmembrane DNA-binding gene (toxR), andV.parahaemolyticusmetalloprotease (vpm) gene using a conventional PCR. The highest mean levels of the presumptiveV.parahaemolyticuswere 9.63×103CFU/g and 1.85×103CFU/mL in the oyster and seawater samples, respectively, during the month of July.V.parahaemolyticuslevels in oyster and seawater samples were significantly positively correlated with water temperature. Of the 165 isolates, 137 (83%), 110 (66.7%), and 108 (65%) weretlh+,vpm+, andtoxR+, respectively. Among theV.parahaemolyticus(tlh+) isolates, 7 (5.1%) and 15 (10.9%) weretdh+andtrh+, respectively, and 24 (17.5%), only oyster isolates, were positive for both genes. Potential pathogenic strains that possessedtdhand/ortrhwere notably higher in oyster (39%) than seawater (15.6%) isolates. The occurrence of totalV.parahaemolyticus(tlh+) was not necessarily proportional to the potential pathogenicV.parahaemolyticus. Co-occurrence of the five genetic markers were observed only among oyster isolates. The co-occurrence of the gene markers showed a relatedness potential oftdhoccurrence withvpm. We believe exploring the role ofV.parahaemolyticusmetalloprotease and whether it is involved in the toxic activity of the thermostable direct hemolysin (TDH) protein can be of significance. The outcomes of this study will provide some foundation for future studies regarding pathogenicVibriodynamics in relation to environmental quality.

Oyster and seawater samples were collected from five sites in the Chesapeake Bay, MD, and three sites in the Delaware Bay, DE, from May to October 2016 and 2017. Abundances and detection frequencies for total and pathogenic Vibrio parahaemolyticus and Vibrio vulnificus were compared using the standard most-probable-number–PCR (MPN-PCR) assay and a direct-plating (DP) method on CHROMagar Vibrio for total (tlh(+)) and pathogenic (tdh(+) and trh(+)) V. parahaemolyticus genes and total (vvhA) and pathogenic (vcgC) V. vulnificus genes. The colony overlay procedure for peptidases (COPP) assay was evaluated for total Vibrionaceae. DP had high false-negative rates (14 to 77%) for most PCR targets and was deemed unsatisfactory. Logistic regression models of the COPP assay showed high concordances with MPN-PCR for tdh(+) and trh(+) V. parahaemolyticus and vvhA(+) V. vulnificus in oysters (85.7 to 90.9%) and seawater (81.1 to 92.7%) when seawater temperature and salinity were factored into the model, suggesting that the COPP assay could potentially serve as a more rapid method to detect vibrios in oysters and seawater. Differences in total Vibrionaceae and pathogenic Vibrio abundances between state sampling sites over different collection years were contrasted for oysters and seawater by MPN-PCR. Abundances of tdh(+) and trh(+) V. parahaemolyticus were ∼8-fold higher in Delaware oysters than in Maryland oysters, whereas abundances of vcgC(+) V. vulnificus were nearly identical. For Delaware oysters, 93.5% were both tdh(+) and trh(+), compared to only 19.2% in Maryland. These results indicate that pathogenic V. parahaemolyticus was more prevalent in the Delaware Bay than in the Chesapeake Bay. IMPORTANCE While V. parahaemolyticus and V. vulnificus cause shellfish-associated morbidity and mortality among shellfish consumers, current regulatory assays for vibrios are complex, time-consuming, labor-intensive, and relatively expensive. In this study, the rapid, simple, and inexpensive COPP assay was identified as a possible alternative to MPN-PCR for shellfish monitoring. This paper shows differences in total Vibrionaceae and pathogenic vibrios found in seawater and oysters from the commercially important Delaware and Chesapeake Bays. Vibrio parahaemolyticus isolates from the Delaware Bay were more likely to contain commonly recognized pathogenicity genes than those from the Chesapeake Bay.

NOAA National Status and Trends Mussel Watch Report indicate the Delaware Bay has regionally medium levels of Cd and high levels of Pb. Environment New Jersey, a non-profit environmental group, reported the Delaware River, providing drinking water to millions, as the fifth most-polluted river in the country. These concerns resulted in this study monitoring water quality conditions near a wastewater facility in Delaware. Physical water quality parameters were measured, along with heavy metals Cd and Pb. Mean metal levels were consistently low at the wastewater discharge (1.3 μg/L Cd, 5.1 μg/L Pb), and high at the control location (9.2 μg/L Cd and 11.5 μg/L of Pb). Relationships were observed between heavy metals, salinity and pH levels. Results suggest water treated by the facility does not pose heavy metal contamination risks to the Lewes Rehoboth Canal. Further studies are warranted to seek heavy metal sources at the control point, farthest from the waste water treatment facility.

The change in the quality attributes (physical, microbial, and chemical) of oysters (Crassostrea virginica) after high hydrostatic pressure (HHP) treatment at 300 MPa at room temperature (RT, 25 °C) 300, 450, and 500 MPa at 0 °C for 2 min and control oysters without treatment were evaluated over 3 wk. The texture and tissue yield percentages of oysters HHP treated at 300 MPa, RT increased significantly (P < 0.05) compared to control. Aerobic and psychrotrophic bacteria in control oysters reached the spoilage point of 7 log CFU/g after 15 d. Coliform counts (log MPN/g) were low during storage with total and fecal coliforms less than 3.5 and 1.0. High pressure treated oysters at 500 MPa at 0 °C were significantly higher (P < 0.05) than oysters HHP treated at 300 MPa at 0 °C in lipid oxidation values. The highest pressure (500 MPa) treatment in this study, significantly (P < 0.05) decreased unsaturated fatty acid percentage compared to control. The glycogen content of control oysters at 3 wk was significantly higher (P < 0.05) when compared to HHP treated oysters [300 MPa, (RT); 450 MPa (0 °C); and 500 MPa (0 °C)]. HHP treatments of oysters were not significantly different in pH, percent salt extractable protein (SEP), and total lipid values compared to control. Based on our results, HHP prolongs the physical, microbial, and chemical quality of oysters.

Consumption of raw oysters is known to cause serious health conditions due to bioaccumulation of contaminants. As filter feeders, oysters ingest bacteria along with phytoplankton from their surrounding habitats. Ensuring seafood safety for human consumption is always a concern. Since oysters are consumed raw, disease causing organisms, environmental contaminants, toxins, chemicals, and even physical hazards such as soils and metals retained in the oysters can enter through feeding. The objective of this study was to determine the quality of oysters collected from Delaware Inland Bays (DIB) and compare them with market oysters. Environmental parameters were monitored from local waters of DIB classified as closed versus open for shellfish harvesting. Total aerobic bacteria and vibrio were higher in market oysters during the warmer months, with open water having the least microbial loads. There were no significant differences in total vibrio counts between the study sites (p=0.396), but significant differences were recorded over time (p=0.004). Water temperature and turbidity were directly proportional to total vibrio in oysters, and salinity was inversely related. Research findings in this study may help bring awareness of changes in bacterial loads due to seasonal changes and additional handling and storage.

The presence of heavy metals, excess nutrients, and microbial contaminants in aquatic systems of coastal Delaware has become a public concern as human population increases and land development continues. Delaware's coastal lagoons have been subjected to problems commonly shared by other coastal Mid-Atlantic states: turbidity, sedimentation, eutrophication, periodic hypoxic/anoxic conditions, toxic substances, and high bacterial levels. The cumulative impact of pollutants from run-off and point sources has degraded water quality, reduced the diversity and abundance of various fish species, invertebrates, and submerged aquatic vegetation. The effects are especially pronounced within the manmade dead end canal systems. In this article, we present selected case studies conducted in the Delaware Inland Bays. Due to the ecological services provided by bivalves, our studies in Delaware Inland Bays are geared toward oysters with special focus on the microbial loads followed by the water quality assessments of the bay. The relationships between oysters (Crassostrea virginica), microbial loads and nutrient levels in the water were investigated. The heavy metal levels monitored further away from the waste water treatment plant in the inland bays are marginally higher than the recommended EPA limits. Also, our studies confirmed that aerobic bacteria and Vibrionaceae levels are salinity dependent. Total bacteria in oysters increased when nitrate and total suspended solids increased in the waters. Studies such as these are important because every year millions of Americans consume raw oysters. Data collected over the last 10 years from our studies may be used to build a predictive index of conditions that are favorable for the proliferation of human pathogenic bacteria. Results from this study will benefit the local community by helping them understand the importance of oyster aquaculture and safe consumption of oysters while making them appreciate their ecological and commercial values. This will also be of tremendous help to the commercial shellfish aquaculture farms to predict poor conditions to prevent oysters' consumption when bacterial levels are high in water.

A mangrove Penicillium producing red pigment was cultured in an optimized medium that was designed by the authors previously and used in this study. The purpose of this study was to identify the pigment and also to study the effect of bio elements on pigment production. Pigment from the medium was efficiently extracted using chloroform, ethyl acetate and n-butanol. Most of the red pigment was extracted into ethyl acetate and further purified by preparative thin layer chromatography. From 1 H and 13 C NMR data supported by electronic imaging mass spectrometry, structure of the compound was elucidated as 2-(4-acetyl phenyl) acetic acid. The yield of pigment produced was studied with respect to various salts and bio elements. Salts at high concentrations (sodium chloride, ammonium sulfate, and sodium nitrite) had a drastic effect on pigment yield because most of the pigment remained adhered to the mycelium instead of diffusing into the medium. Also, when bio elements were supplemented to the medium; calcium, iron, and zinc enhanced pigment yield whereas; potassium, magnesium, copper and manganese did not have significant impact on pigment production. Lead had a drastic negative effect on the pigment yield. Therefore, this study proves that salts and bio elements play a major role in the production of various metabolites from mangrove fungi. Keywords: Penicillium , 2-(4-acetyl phenyl) acetic acid, bio elements, salts, soluble pigment. African Journal of Biotechnology , Vol 13(26) 2668-2674

Extracellular metabolites produced by harmful algae can act as growth-inhibiting agents for other phytoplankton species, influencing species competition and succession and hence affecting structure of the plankton community. Karlodinium veneficum Ballant., a cosmopolitan estuarine dinoflagellate, produces toxic compounds known as karlotoxins that exhibit sterol-dependent, cytotoxic activity and are frequently associated with fish kills. Karlotoxin-sensitive cells tend to have desmethyl sterols as predominant cellular sterols, and karlotoxin-resistant cells have 4-methyl sterols as dominant sterols. The allelopathic effects of karlotoxins on other algae have been described, but the question of whether or not K. veneficum is allelopathic against Prorocentrum minimum, a common co-occurring dinoflagellate, is unknown. We determined the sterol profiles of two different Chesapeake Bay strains (RR4B1 and IB) of P. minimum and also exposed them to different concentrations of karlotoxin extracted from K. veneficum cells. The strains, RR4B1 and IB, experienced mortality at high toxin concentrations, i.e., 256 ng mL -1 . After 24 hours of exposure, cell counts declined resulting in calculated “negative growth rates” of -1.17 (d -1 ) for RR4B1 and

The Intergovernmental Panel on Climate Change (IPCC), established by the United Nations and World Meteorological Organization, has determined with a 90% confidence interval that humans have very likely contributed to a net warming of the Earth due to an increase in the emissions of greenhouse gases, aerosols, and land use changes. This warming has caused glacial melting to accelerate and subsequently sea level is now a very tangible issue. In addition, extreme precipitation events are happening more often in certain geographic regions. The last few decades have seen tremendous efforts focused on the collection and distribution of scientific data to better understand trends and future projections/scenarios of climate change and how society must adapt to those changes. As science concerning global climate change advances, societal awareness and understanding of the issue appears to be lagging behind. Does the public have a solid understanding of the mechanisms and consequences of climate change? Depending on the type of government, public views can significantly influence the government to develop better climate policies. Therefore, public voice is vital in influencing political decisions concerning climate change. Clear communication of scientific knowledge can empower people to safely steer future generations out of harm’s way - sharing and understanding fosters more of the same possibility. This case study discusses one of the interactive classroom activities which facilitated the active engagement of students in a discussion of local issues and potential avenues to adapt to climate change. Because climate change affects everything on our planet, animal farms on Delmarva represent one of the many economically and socially critical variables that must be protected through preemptive adaptations. Conversely, farm operations affect the rate of climate change, as well as the surrounding environment. With modern management practices and technology, farming effects on the environment and climate can be drastically reduced. On the other hand, if operations are not managed properly they can also have a negative impact on the environment and climate. Through suggestions and the adoption of modern practices, animal farming can become sustainable and environmentally friendly. The earth’s climate is inherently dynamic, but with the adoption of sustainable farming practices on a global scale the rate of climate change may be decelerated.