title: Interactions between oral bacteria: inhibition of Streptococcus mutans bacteriocin production by Streptococcus gordonii.
abstract: Streptococcus mutans has been recognized as an important etiological agent in human dental caries. Some strains of S. mutans also produce bacteriocins. In this study, we sought to demonstrate that bacteriocin production by S. mutans strains GS5 and BM71 was mediated by quorum sensing, which is dependent on a competence-stimulating peptide (CSP) signaling system encoded by the com genes. We also demonstrated that interactions with some other oral streptococci interfered with S. mutans bacteriocin production both in broth and in biofilms. The inhibition of S. mutans bacteriocin production by oral bacteria was stronger in biofilms than in broth. Using transposon Tn916 mutagenesis, we identified a gene (sgc; named for Streptococcus gordonii challisin) responsible for the inhibition of S. mutans bacteriocin production by S. gordonii Challis. Interruption of the sgc gene in S. gordonii Challis resulted in attenuated inhibition of S. mutans bacteriocin production. The supernatant fluids from the sgc mutant did not inactivate the exogenous S. mutans CSP as did those from the parent strain Challis. S. gordonii Challis did not inactivate bacteriocin produced by S. mutans GS5. Because S. mutans uses quorum sensing to regulate virulence, strategies designed to interfere with these signaling systems may have broad applicability for biological control of this caries-causing organism.
authors.affiliation: Department of Oral Biology, State University of New York at Buffalo, 3435 Main St., Buffalo, NY 14214, USA.
authors.forename: Bing-Yan
authors.initials: BY
authors.lastname: Wang
authors.forename: Howard K
authors.initials: HK
authors.lastname: Kuramitsu
mesh_terms: D000898:Antibiosis; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001430:Bacteriocins / Q000096:biosynthesis*; D018441:Biofilms / Q000254:growth & development; D003470:Culture Media; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D009055:Mouth / Q000382:microbiology*; D009154:Mutation; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism; D011498:Protein Precursors; D021382:Protein Sorting Signals; D015398:Signal Transduction; D013291:Streptococcus / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D013295:Streptococcus mutans / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D001430:Bacteriocins; D003470:Culture Media; D011498:Protein Precursors; D021382:Protein Sorting Signals; C423628:competence factor, Streptococcus; D010447:Peptide Hydrolases