Erwinia amylovora is a gram-negative phytopathogen that causes fire blight of pome fruit and related members of the family Rosaceae. We sequenced the putative autoinducer-2 (AI-2) synthase gene luxS from E. amylovora. Diversity analysis indicated that this gene is extremely conserved among E. amylovora strains. Quorum sensing mediated by LuxS has been implicated in coordinated gene expression, ...

The ubiquitous protein LuxS with S-ribosylhomocysteinase activity is involved in S-adenosyl methionine detoxification, C-1 unit recycling and the production of autoinducers that allow the cell to sense and respond to cell density. Independent reports describe the impact of LuxS deficiency on Streptococcus pneumoniae virulence in the mouse. In vitro, LuxS deficiency confers discrete phenotypes. ...

Abstract Background Streptococcus suis type 2 (SS2) is an important zoonotic pathogen. We have previously reported the structure of LuxS protein and found that luxS gene closely related to biofilm, virulence expression drug resistance SS2. However, mechanism mediated SS2 stress response unclear. Therefore, this experiment performed mutant (Δ ) complement strain ( C Δ ), overexpression +) wild-t...

The enzyme LuxS is responsible for the production of autoinducer-2 (AI-2), a molecule that has been implicated in quorum sensing in many bacterial species. This study investigated whether there is a luxS-dependent signalling system in the Gram-negative bacteria Serratia spp. Serratia marcescens is a broad-host-range pathogen and an important cause of nosocomial infections. Production of AI-2 ac...

Numerous pathogenic bacteria contain luxS, which is required for autoinducer-2 production. Here, we demonstrate that Neisseria meningitidis contains a functional copy of luxS that is necessary for full meningococcal virulence; strains with a luxS deletion are defective for bacteremia, a prerequisite of meningococcal pathogenesis.

Different species of bacteria important in the composition of dental plaque were tested for production of extracellular autoinducer-like activities that stimulate the expression of the luminescence genes in Vibrio harveyi. Several strains of Prevotella intermedia, Fusobacterium nucleatum, and Porphyromonas gingivalis were found to produce such activities. Interestingly, these bacteria belong to...

The LuxS protein is required for the biosynthesis of the type 2 autoinducer (AI-2), which is involved in quorum sensing in a wide range of bacterial species. We have determined the effects of a defined luxS mutation on the virulence of Streptococcus pneumoniae. Although the luxS mutant displayed reduced virulence relative to its wild-type parent, the type 2 strain D39, it was by no means avirul...

AI-2-mediated quorum sensing has been identified in various bacteria, including both Gram-negative and Gram-positive species, and numerous phenotypes have been reported to be regulated by this mechanism, using the luxS-mutant strain. But the AI-2 production process confused this regulatory function; some considered this regulation as the result of a metabolic change, which refers to an importan...

It is generally believed that probiotic bacteria need to survive gastrointestinal transit to exert a health-promoting effect. In this study, a genuine luxS mutant and a luxS mutant containing unknown suppressor mutations of the probiotic strain Lactobacillus rhamnosus GG were compared to the wild type for survival and persistence in the murine gastrointestinal tract. The LuxS enzyme, catalyzing...

The expression of a wide variety of physiological functions in many bacterial species is modulated by quorum sensing, a population-dependent signalling mechanism that involves the production and detection of extracellular signalling molecules. The genome sequence of Campylobacter jejuni NCTC 11168 contains a gene encoding an orthologue of LuxS, which is required for autoinducer-2 (AI-2) product...