title: Evidence for a signaling system in Helicobacter pylori: detection of a luxS-encoded autoinducer.
abstract: Helicobacter pylori possesses a homolog of the luxS gene, initially identified by its role in autoinducer production for the quorum-sensing system 2 in Vibrio harveyi. The genomes of several other species of bacteria, notably Escherichia coli, Salmonella enterica serovar Typhimurium, and Vibrio cholerae, also include luxS homologs. All of these bacteria have been shown to produce active autoinducers capable of stimulating the expression of the luciferase operon in V. harveyi. In this report, we demonstrate that H. pylori also synthesizes a functional autoinducer (AI-2) that can specifically activate signaling system 2 in V. harveyi. Maximal activity is produced during early log phase, and the activity is diminished when cells enter stationary phase. We show that AI-2 is not involved in modulating any of the known or putative virulence factors in H. pylori and that a luxS null mutant has a two-dimensional protein profile identical to that of its isogenic parent strain. We discuss the implications of having an AI-2-like quorum-sensing system in H. pylori and suggest possible roles that it may play in H. pylori infection.
authors.affiliation: Department of Microbiology and Molecular Biology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
authors.forename: E A
authors.initials: EA
authors.lastname: Joyce
authors.forename: B L
authors.initials: BL
authors.lastname: Bassler
authors.forename: A
authors.initials: A
authors.lastname: Wright
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D013437:Carbon-Sulfur Lyases; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D015870:Gene Expression; D016480:Helicobacter pylori / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D017386:Sequence Homology, Amino Acid; D014407:Tumor Cells, Cultured; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria