Luminescence in Vibrio fischeri is controlled by a population density-responsive regulatory mechanism called quorum sensing. Elements of the mechanism include: LuxI, an acyl-homoserine lactone (acyl-HSL) synthase that directs synthesis of the diffusible signal molecule, 3-oxo-hexanoyl-HSL (V. fischeri autoinducer-1, VAI-1); LuxR, a transcriptional activator protein necessary for response to VAI...

Rhodobacter sphaeroides is a free-living, photoheterotrophic bacterium known for its genomic and metabolic complexity. We have discovered that this purple photosynthetic organism possesses a quorum-sensing system. Quorum sensing occurs in a number of eukaryotic host-associated gram-negative bacteria. In these bacteria there are two genes required for quorum sensing, the luxR and luxI homologs, ...

BACKGROUND Quorum sensing (QS) networks are more commonly known as acyl homoserine lactone (HSL) networks. Recently, p-coumaroyl-HSL has been found in a photosynthetic bacterium. p-coumaroyl-HSL is derived from a lignin monomer, p-coumaric acid, rather than a fatty acyl group. The p-coumaroyl-HSL may serve an ecological role in diverse QS pathways between p-coumaroyl-HSL producing bacteria and ...

Virulence and adaptability of many Gram-negative bacterial species are associated with an N-acylhomoserine lactone (AHL) gene regulation mechanism called quorum sensing (QS). The arrangement of quorum sensing genes is variable throughout bacterial genomes, although there are unifying themes that are common among the various topological arrangements. A bioinformatics survey of 1,403 complete bac...

SdiA of E. coli and Salmonella is a LuxR homolog that detects N-acyl homoserine lactones (AHLs). Most LuxR homologs function together with a cognate AHL synthase (a LuxI homolog), but SdiA does not. Instead, SdiA detects AHLs produced by other bacterial species. In this report, we performed a phylogenetic analysis of SdiA. The results suggest that one branch of the Enterobacteriaceae obtained a...

Members of the Roseobacter clade are ecologically important and numerically abundant in coastal environments and can associate with marine invertebrates and nutrient-rich marine snow or organic particles, on which quorum sensing (QS) may play an important role. In this review, we summarize current research progress on roseobacterial acyl-homoserine lactone-based QS, particularly focusing on thr...

background: luxi is a component of the quorum sensing signaling pathway in vibrio fischeri responsible for the inducer synthesis that is essential for bioluminescence. methods: homology modeling of luxi was carried out using phyre2 and refined with the galaxyweb server. five models were generated and evaluated by errat, anolea, qmean6, and procheck. results: five refined models were generated b...

UNLABELLED Burkholderia thailandensis has three acyl-homoserine lactone (AHL) LuxR-LuxI quorum-sensing circuits and two orphan LuxR homologs. Orphans are LuxR-type transcription factors that do not have cognate LuxI-type AHL synthases. One of the orphans, MalR, is genetically linked to the mal gene cluster, which encodes enzymes required for production of the cytotoxic polyketide malleilactone....

Harvard Medical School now recognized as players in widely used mechanisms Boston, Massachusetts 02115 for sensing cell numbers among gram-negative bacteria, the role of acylated HSLs as signal molecules was first discovered in the studies of the high cell density induc-Microbial Differentiation in Response tion of bioluminescence in the marine bacterium Vibrio to Starvation fischeri. The machi...

Quorum sensing (QS) is the ability of microbes to sense and respond to their own population density, which typically results in cooperative activity (Fuqua et al., 1994). This form of microbial communication is important to agriculture and human health as they often participate in the regulation of genes important for host interactions. The classic example of QS in bacteria is performed by the ...