The abundance of Vibrio vulnificus in coastal environments has been linked to water temperature, while its relationship to salinity is less clear. We have developed a culture-independent, most-probable-number quantitative PCR approach to examine V. vulnificus population dynamics in Barnegat Bay, N.J. Based on the combined analysis of our results from Barnegat Bay and from the literature, the present data show that (i) V. vulnificus population dynamics are strongly correlated to water temperature and (ii) although the general trend is for V. vulnificus abundance to be inversely correlated with salinity, this relationship depends on salinity levels. Irrespective of temperature, high abundances of V. vulnificus are observed at 5 to 10 ppt, which thus appears to be the optimal salinity regime for their survival. At 20 to 25 ppt, V. vulnificus abundances show a positive correlation to salinity. Unsuccessful attempts to resuscitate V. vulnificus, combined with our inability to detect cells during the winter despite an assay adapted to detect viable but nonculturable (VBNC) cells, suggest that the decline and eventual disappearance of V. vulnificus from the water column during the winter months is due primarily to a significant reduction in population size and is not only the consequence of cells entering the VBNC state. These findings are in line with the hypothesis that the sediment serves as a refuge for a subpopulation of V. vulnificus over the winter and weather-driven mixing events during the spring initiate a summer bloom in the water column.Vibrio vulnificus is a halophilic gamma proteobacterium endemic to temperate coastal waters. This bacterium is a major concern to public heath agencies and the shellfish industry because it is an opportunistic human pathogen found ubiquitously in the water column and sediment and as an intracellular symbiont of shellfish (5, 13, 49). Most environmental assessments of V. vulnificus have centered on coastal waters surrounding Gulf Coast states (23,28,30,43,46), and a few studies have reported the presence of this organism along the eastern (15, 41, 50) and western coasts (22) of the United States and the Mediterranean coast (3, 16). Together with laboratory experiments, these studies showed that V. vulnificus undergoes a striking seasonal fluctuation in estuarine waters, with water temperature being the major factor controlling the abundance of V. vulnificus. The highest abundances of this organism, both in the water column and in association with shellfish (43, 50), occur in warm waters (typically exceeding 20°C) of moderate salinity (ranging from 5 to 25 ppt) (8,18,20). The abundance as well as the incidence of V. vulnificusrelated disease decreases with temperature to the point where it is usually undetectable during the winter months. Salinity has also been identified as playing a role in controlling V. vulnificus abundance, though its effect on V. vulnificus is less clear. Several studies have identified an inverse correlation between V. vulnificus abundance (50) and sali...

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Microarrays have enabled the determination of how thousands of genes are expressed to coordinate function within single organisms. Yet applications to natural or engineered communities where different organisms interact to produce complex properties are hampered by theoretical and technological limitations. Here we describe a general method to accurately identify low-abundant targets in systems containing complex mixtures of homologous targets. We combined an analytical predictor of nonspecific probe–target interactions (cross-hybridization) with an optimization algorithm that iteratively deconvolutes true probe–target signal from raw signal affected by spurious contributions (cross-hybridization, noise, background, and unequal specific hybridization response). The method was capable of quantifying, with unprecedented specificity and accuracy, ribosomal RNA (rRNA) sequences in artificial and natural communities. Controlled experiments with spiked rRNA into artificial and natural communities demonstrated the accuracy of identification and quantitative behavior over different concentration ranges. Finally, we illustrated the power of this methodology for accurate detection of low-abundant targets in natural communities. We accurately identified Vibrio taxa in coastal marine samples at their natural concentrations (<0.05% of total bacteria), despite the high potential for cross-hybridization by hundreds of different coexisting rRNAs, suggesting this methodology should be expandable to any microarray platform and system requiring accurate identification of low-abundant targets amid pools of similar sequences.

Non-tumor hyperandrogenism with markedly elevated serum T and associated metabolic syndrome is a defined clinical entity in postmenopause as well as in premenopausal women with polycystic ovary syndrome. This has hitherto been only sparsely documented in the published literature. A fall in serum T level in response to insulin-sensitizing therapy with metformin and lifestyle change may be a reassuring indicator that such women are highly unlikely to harbor an androgen-secreting tumor.

A novel quantitative PCR (QPCR) approach, which combines competitive PCR with constant-denaturant capillary electrophoresis (CDCE), was adapted for enumerating microbial cells in environmental samples using the marine nanoflagellate Cafeteria roenbergensis as a model organism. Competitive PCR has been used successfully for quantification of DNA in environmental samples. However, this technique is labor intensive, and its accuracy is dependent on an internal competitor, which must possess the same amplification efficiency as the target yet can be easily discriminated from the target DNA. The use of CDCE circumvented these problems, as its high resolution permitted the use of an internal competitor which differed from the target DNA fragment by a single base and thus ensured that both sequences could be amplified with equal efficiency. The sensitivity of CDCE also enabled specific and precise detection of sequences over a broad range of concentrations. The combined competitive QPCR and CDCE approach accurately enumerated C. roenbergensis cells in eutrophic, coastal seawater at abundances ranging from approximately 10 to 10 4 cells ml ؊1 . The QPCR cell estimates were confirmed by fluorescent in situ hybridization counts, but estimates of samples with <50 cells ml ؊1 by QPCR were less variable. This novel approach extends the usefulness of competitive QPCR by demonstrating its ability to reliably enumerate microorganisms at a range of environmentally relevant cell concentrations in complex aquatic samples.