Evaluation of salinity and temperature as stress factors affecting the enumeration of fecal coliforms by the electrochemical detection method

The ability of an electrochemical detection method to predict viable numbers of fecal coliforms was evaluated under laboratory conditions with respect to seawater adjusted to various salinities and temperatures. The viability of an Escherchia coli isolat~ as measured by the spread plate technique utilizing non-selective media was unaffected after 12 wk exposure at 2°C and 25 °100 salinity. At higher temperatures (15-30°C) both the total decrease in cell numbers as well as the rates of die-off were greater than at 2°C. There was little apparent difference in viability across the temperature range 15-30°C. Viability was observed to be inversely related to salinity over the range 10-30 °100. Stress was measured using the electrochemical detection method (ECDM) and defined as the difference between the predicted endpoint response time (ER) calculated from a standard curve and the observed ER time. Seawater of higher salinities generally produced greater stress. (...

Coliform Depuration Of Chesapeake Bay Oysters

Oysters contaminated in nature depurated fecal coliforms to levels below 50/100 g in 48 hr over a wide range of environmental conditions typical of the lower Chesapeake Bay region. Temperature was found to be the most crilical environmental factor with conditions below 10-12°C having the potential of inhibiting depuration. Coliform clearance did not appear to be correlated with pumping rate or biodeposition activity of oysters. Oysters infected with the pathogens Dermocystidium marinum and Minchinia nelsoni (MSX) depurated as rapidly as uninfected ones. Meat quality and size of oysters likewise did not affect depuration. Four commercial-size tanks of different designs were found to yield satisfactory results in 48 hr. Water flow rates over the ranges studied and location of trays within the tanks did not influence depuration. Biodeposits contained high levels of total and fecal coliforms, but their accumulation in the tanks did not have a detrimental effect under the conditions studied. Pooling oysters during monitoring of\u27 depuration samples was necessary due lo the variation of coliform levels in individual oysters. Samples of 6-8 pooled oysters appeared to be adequate for estimating coliform levels. The Medium A-1 test was superior to the elevated temperature coliform plate_ (ETCP) procedure of Cabelli and Heffernan for determination of fecal coliforms in oysters.https://scholarworks.wm.edu/vimsbooks/1020/thumbnail.jp

High Salinity Relay as a Postharvest Processing Strategy To Reduce Vibrio vulnificus Levels in Chesapeake Bay Oysters (Crassostrea virginica)

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 (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\u27s 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 (

A unique Mycobacterium species isolated from an epizootic of striped bass (Morone saxatilis)

We isolated a Mycobacterium sp. resembling Mycobacterium marinum and M. ulcerans from diseased striped bass (Morone saxatilis) during an epizootic of mycobacteriosis in the Chesapeake Bay. This isolate may represent an undescribed Mycobacterium species, based on phenotypic characteristics and comparative 16S rRNA gene sequence

Align And Refine: Using The Taxonomy Of Significant Learning To Plan For FYS Faculty Development

Our faculty development (FD) work applies Dee Fink’s (2013) integrated course design model. In this article, we describe the situational factors related to supporting faculty who teach a required, academically-focused First Year Seminar course at a large public university. We then describe how we designed a suite of FD opportunities with goals that directly responded to those situational factors. Finally, we offer a process for designing FD initiatives that can work for other programs even when their situational factors and goals are different

Publisher Correction: Understanding the genetic complexity of puberty timing across the allele frequency spectrum

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Understanding the genetic complexity of puberty timing across the allele frequency spectrum

Pubertal timing varies considerably and is associated with later health outcomes. We performed multi-ancestry genetic analyses on ~800,000 women, identifying 1,080 signals for age at menarche. Collectively, these explained 11% of trait variance in an independent sample. Women at the top and bottom 1% of polygenic risk exhibited ~11 and ~14-fold higher risks of delayed and precocious puberty, respectively. We identified several genes harboring rare loss-of-function variants in ~200,000 women, including variants in ZNF483, which abolished the impact of polygenic risk. Variant-to-gene mapping approaches and mouse gonadotropin-releasing hormone neuron RNA sequencing implicated 665 genes, including an uncharacterized G-protein-coupled receptor, GPR83, which amplified the signaling of MC3R, a key nutritional sensor. Shared signals with menopause timing at genes involved in DNA damage response suggest that the ovarian reserve might signal centrally to trigger puberty. We also highlight body size-dependent and independent mechanisms that potentially link reproductive timing to later life disease

Understanding the genetic complexity of puberty timing across the allele frequency spectrum

Pubertal timing varies considerably and is associated with later health outcomes. We performed multi-ancestry genetic analyses on ~800,000 women, identifying 1,080 signals for age at menarche. Collectively, these explained 11% of trait variance in an independent sample. Women at the top and bottom 1% of polygenic risk exhibited ~11 and ~14-fold higher risks of delayed and precocious puberty, respectively. We identified several genes harboring rare loss-of-function variants in ~200,000 women, including variants in ZNF483, which abolished the impact of polygenic risk. Variant-to-gene mapping approaches and mouse gonadotropin-releasing hormone neuron RNA sequencing implicated 665 genes, including an uncharacterized G-protein-coupled receptor, GPR83, which amplified the signaling of MC3R, a key nutritional sensor. Shared signals with menopause timing at genes involved in DNA damage response suggest that the ovarian reserve might signal centrally to trigger puberty. We also highlight body size-dependent and independent mechanisms that potentially link reproductive timing to later life disease