title: Synergistic effects of streptococcal glucosyltransferases on adhesive biofilm formation.
abstract: Glucosyltransferases (GTF)-I and GTF-SI of Streptococcus mutans synthesize water-insoluble and both water-soluble and -insoluble glucans, respectively, and play essential roles in the sucrose-dependent adhesion of the organism to tooth surfaces. To examine the interactions of different GTFs on artificial biofilm formed by S. mutans and other oral streptococci, we generated GTF-I- and GTF-SI-hyperproducing isogenic mutant strains. Transformant B42-21, which hyperexpressed GTF-SI, exhibited firm adhesion in the presence of sucrose, whereas transformant B42-10, which hyperexpressed GTF-I, failed to exhibit firm adhesion. Furthermore, co-culture of transformant B42-21 with water-soluble glucan-synthesizing Streptococcus sanguinis yielded firm adhesion, while the addition of dextran T10 to B42-21 growing culture had no effect on adhesion. These findings suggest that GTF-SI has a strong effect on sucrose-dependent adhesion and is essential for biofilm formation on smooth surfaces, in cooperation with water-soluble glucans synthesized de novo by oral streptococci that inherently lack cell adhesion ability.
authors.affiliation: Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita-Osaka 5650871, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tamesada
authors.forename: S
authors.initials: S
authors.lastname: Kawabata
authors.forename: T
authors.initials: T
authors.lastname: Fujiwara
authors.forename: S
authors.initials: S
authors.lastname: Hamada
mesh_terms: D000704:Analysis of Variance; D001422:Bacterial Adhesion / Q000502:physiology*; D001426:Bacterial Proteins / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D015153:Blotting, Western; D018920:Coculture Techniques; D017753:Ecosystem; D004591:Electrophoresis, Polyacrylamide Gel; D005822:Genetic Vectors; D005936:Glucans / Q000096:biosynthesis; D005964:Glucosyltransferases / Q000378:metabolism*; D012995:Solubility; D013045:Species Specificity; D013291:Streptococcus / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D013295:Streptococcus mutans / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D014169:Transformation, Bacterial
chemical_list: D001426:Bacterial Proteins; D005936:Glucans; D005964:Glucosyltransferases; C489364:glucosyltransferase I