Pseudomonas aeruginosa quorum control of gene expression involves three LuxR-type signal receptors LasR, RhlR, and QscR that respond to the LasI- and RhlI-generated acyl-homoserine lactone (acyl-HSL) signals 3OC12-HSL and C4-HSL. We found that a LasR-RhlR-QscR triple mutant responds to acyl-HSLs by regulating at least 37 genes. LuxR homolog-independent activation of the representative genes ant...

The Pseudomonas aeruginosa LasR protein functions in concert with N-3-oxo-dodecanoyl-L-homoserine lactone (3O-C(12)-HSL) to coordinate the expression of target genes, including many genes that encode virulence factors, with cell density. We used a LexA-based protein interaction assay to demonstrate that LasR forms multimers only when 3O-C(12)-HSL is present. A series of LasR molecules containin...

The Pseudomonas aeruginosa las (lasR-lasI) and rhl (rhlR-rhlI) quorum-sensing systems regulate the expression of several virulence factors, including elastase and rhamnolipid. P. aeruginosa strain PR1-E4 is a lasR deletion mutant that contains a second, undefined mutation which allows production of elastase and rhamnolipid despite a nonfunctional las system. We have previously shown that this s...

CRISPR-Cas loci encode for an adaptive immune system in prokaryotes that provides defense against viruses (1) and plasmids (2) that infect these organisms. CRISPR loci contain a series of repetitive sequences intercalated with short sequences derived from invading viruses and plasmids (3–5). These short sequences, called spacers, are acquired from the invader upon infection during an “immunizat...

More than 30 years ago microbiologists found a way to induce luminescent bacteria to emit light prematurely. By adding cell-free culture fluid from a bright bioluminescent culture at high cell density to a nonluminous low-cell-density culture, they were able to eliminate the characteristic lag in bioluminescence (5, 12, 16). Nealson et al. proved that the “light switch” that controls the biolum...

Abstract Background Life satisfaction is one of the most important components a person’s overall quality life and vital element successful ageing. Few studies have previously attempted to investigate level among Indian older adults; however, majority them were at risk omitted variable bias. This study, while controlling for household-level unobserved confounders, aims correlates adults using ho...

Pseudomonas aeruginosa is an opportunistic pathogen, having complicated quorum sensing (QS) system utilizing multiple signals and receptors to coordinate virulence pathogenicity. N-acyl-homoserine-lactones (AHLs) are the most common autoinducers responsible for regulation of QS-mediated gene expression. There four QS systems in P. among which LasI/R RhlI/R regulated by 3-oxo-C12-HSL C4-HSL resp...