Contribution of glucan‐binding protein A to firm and stable biofilm formation by Streptococcus mutans. (10th November 2014)

• Record Type: Journal Article
• Authors: Matsumi, Y.; Fujita, K.; Takashima, Y.; Yanagida, K.; Morikawa, Y.; Matsumoto‐Nakano, M.
• Is Part Of: Molecular oral microbiology. Volume 30:Number 3(2015)
• Page Start: 217
• Page End: 226
• Publication Date: 2014-11-10
• Subjects: Mouth -- Microbiology -- Periodicals; Respiratory infections -- Microbiology -- Periodicals; Mouth -- Diseases -- Immunological aspects -- Periodicals; 617.522
• DOI: 10.1111/omi.12085
• Languages: English
• ISSNs: 2041-1006

Abstract

<abstract abstract-type="main" id="omi12085-abs-0001"> <title>Summary</title> <p>Glucan‐binding proteins (Gbps) of <italic>Streptococcus mutans</italic>, a major pathogen of dental caries, mediate the binding of glucans synthesized from sucrose by the action of glucosyltransferases (GTFs) encoded by <italic>gtfB</italic>, <italic> gtfC</italic>, and <italic>gtfD</italic>. Several stress proteins, including DnaK and GroEL encoded by <italic>dnaK</italic> and <italic>groEL</italic>, are related to environmental stress tolerance. The contribution of Gbp expression to biofilm formation was analyzed by focusing on the expression levels of genes encoding GTFs and stress proteins. Biofilm‐forming assays were performed using GbpA‐, GbpB‐, and GbpC‐deficient mutant strains and the parental strain MT8148. The expression levels of <italic>gtfB</italic>, <italic> gtfC</italic>, <italic> gtfD</italic>, <italic> dnaK</italic>, and <italic>groEL</italic> were evaluated by reverse transcription‐quantitative polymerase chain reaction (RT‐qPCR). Furthermore, the structure of biofilms formed by these Gbp‐deficient mutant strains was observed using confocal laser scanning microscopy (CLSM). Biofilm‐forming assay findings demonstrated that the amount formed by the GbpA‐deficient mutant strain (AD1) was nearly the same as that by the parental strain, while the GbpB‐ and GbpC‐deficient mutant strains produced lower amounts than MT8148. Furthermore, RT‐qPCR assay results showed that the expressions of <italic>gtfB</italic>, <italic> dnaK</italic>, and <italic>groEL</italic> in AD1 were elevated compared with MT8148. CLSM also revealed that the structure of biofilm formed by AD1 was prominently different compared with that formed by the parental strain. These results suggest that a defect in GbpA influences the expression of genes controlling biofilm formation, indicating its importance as a protein for firm and stable biofilm formation.</p> </abstract>