Interlaboratory performance and quantitative PCR data acceptance metrics for NIST SRM® 2917.

Surface water quality quantitative polymerase chain reaction (qPCR) technologies are expanding from a subject of research to routine environmental and public health laboratory testing. Readily available, reliable reference material is needed to interpret qPCR measurements, particularly across laboratories. Standard Reference Material® 2917 (NIST SRM® 2917) is a DNA plasmid construct that functions with multiple water quality qPCR assays allowing for estimation of total fecal pollution and identification of key fecal sources.

Indole Inhibits ToxR Regulon Expression in .

Indole is a degradation product of tryptophan that functions as a signaling molecule in many bacteria. This includes , where indole was shown to regulate biofilm and type VI secretion in nontoxigenic environmental isolates. Indole is also produced by toxigenic strains in the human intestine, but its significance in the host is unknown.

The Vibrio cholerae RND efflux systems impact virulence factor production and adaptive responses via periplasmic sensor proteins.

Resistance-nodulation-division (RND) efflux systems are ubiquitous transporters in Gram-negative bacteria that are essential for antibiotic resistance. The RND efflux systems also contribute to diverse phenotypes independent of antimicrobial resistance, but the mechanism by which they affect most of these phenotypes is unclear. This is the case in Vibrio cholerae where the RND systems function in antimicrobial resistance and virulence factor production.

Vibrio cholerae LeuO Links the ToxR Regulon to Expression of Lipid A Remodeling Genes.

Vibrio cholerae is an intestinal pathogen that causes the diarrheal disease cholera. Colonization of the intestine depends upon the expression of genes that allow V. cholerae to overcome host barriers, including low pH, bile acids, and the innate immune system.

Vibrio cholerae leuO Transcription Is Positively Regulated by ToxR and Contributes to Bile Resistance.

Unlabelled: Vibrio cholerae is an aquatic organism and facultative human pathogen that colonizes the small intestine. In the small intestine, V. cholerae is exposed to a variety of antimicrobial compounds, including bile.

Substrate-dependent activation of the Vibrio cholerae vexAB RND efflux system requires vexR.

Vibrio cholerae encodes six resistance-nodulation-division (RND) efflux systems which function in antimicrobial resistance, virulence factor production, and intestinal colonization. Among the six RND efflux systems, VexAB exhibited broad substrate specificity and played a predominant role in intrinsic antimicrobial resistance. The VexAB system was encoded in an apparent three gene operon that included vexR; which encodes an uncharacterized TetR family regulator.