LuxS catalyzes the synthesis of the quorum-sensing signaling molecule autoinducer 2. We show that in Salmonella enterica serovar Typhimurium, deletion of the luxS gene polarizes flagellar phase variation toward the more immunogenic phase 1 flagellin. This phenotype is complementable by luxS in trans but is independent of quorum-sensing signals.

Quorum sensing is involved in the regulation of multicellular behavior through communication via small molecules. Given the high number and diversity of the gastrointestinal microbiota, it is postulated that members of this community communicate to coordinate a variety of adaptive processes. AI-2 is suggested to be a universal bacterial signaling molecule synthesized by the LuxS enzyme, which f...

Quorum-sensing (QS), the regulation of bacterial gene expression in response to changes in cell density, involves pathways that synthesize signaling molecules (auto-inducers). The luxS/AI-2-mediated QS system has been identified in both gram-positive and gram-negative bacteria. Bacillus anthracis, the etiological agent of anthrax, possesses genes involved in luxS/AI-2-mediated QS, and deletion ...

Biofilm is a sessile bacterial accretion embedded in self-producing matrix. It is the root cause of about 80% microbial infections in human. Among them, E. coli biofilms are most prevalent in medical devices associated nosocomial infections. The objective of this study was to inhibit biofilm formation by targeting gene involved in quorum sensing, one of the main mechanisms of biofilm formation....

Quorum sensing is a bacterial mechanism for regulating gene expression in response to changes in population density. Many bacteria are capable of acyl-homoserine lactone-based or peptide-based intraspecies quorum sensing and luxS-dependent interspecies quorum sensing. While there is good evidence about the involvement of intraspecies quorum sensing in bacterial biofilm, little is known about th...

Communication based on autoinducer 2 (AI-2) is widespread among gram-negative and gram-positive bacteria, and the AI-2 pathway can control the expression of genes involved in a variety of metabolic pathways and pathogenic mechanisms. In the present study, we identified luxS, a gene responsible for the synthesis of AI-2, in Streptococcus gordonii, a major component of the dental plaque biofilm. ...

Cell-to-cell communication in bacteria is mediated by quorum-sensing systems (QSS) that produce chemical signal molecules called autoinducers (AI). In particular, LuxS/AI-2-dependent QSS has been proposed to act as a universal lexicon that mediates intra- and interspecific bacterial behavior. Here we report that the model organism Bacillus subtilis operates a luxS-dependent QSS that regulates i...

LuxS/AI-2 quorum sensing (QS) system involves the production of cell signaling molecules via luxS-based autoinducer-2 (AI-2). LuxS has been reported to plays critical roles in regulating various behaviors of bacteria. AI-2 is a byproduct of the catabolism of S-adenosylhomocysteine (SAH) performed by the LuxS and Pfs enzymes. In our previous study, the function of LuxS in AI-2 production was ver...

In the present study we show that luxS of Bifidobacterium breve UCC2003 is involved in the production of the interspecies signaling molecule autoinducer-2 (AI-2), and that this gene is essential for gastrointestinal colonization of a murine host, while it is also involved in providing protection against Salmonella infection in Caenorhabditis elegans. We demonstrate that a B. breve luxS-insertio...

Quorum sensing is a phenomenon defined as gene regulation in response to cell density that regulates various functions in bacteria. The periodontopathogen Porphyromonas gingivalis possesses a luxS gene homologue that may encode a quorum-sensing system. In order to identify genes of P. gingivalis that are regulated by luxS, gene expression analysis was done using microarrays and RNA samples from...