title: Proteome analysis identifies the Dpr protein of Streptococcus mutans as an important factor in the presence of early streptococcal colonizers of tooth surfaces.
abstract: Oral streptococci are primary colonizers of tooth surfaces and Streptococcus mutans is the principal causative agent of dental caries in humans. A number of proteins are involved in the formation of monospecies biofilms by S. mutans. This study analyzed the protein expression profiles of S. mutans biofilms formed in the presence or absence of S. gordonii, a pioneer colonizer of the tooth surface, by two-dimensional gel electrophoresis (2-DE). After identifying S. mutans proteins by Mass spectrometric analysis, their expression in the presence of S. gordonii was analyzed. S. mutans was inoculated with or without S. gordonii DL1. The two species were compartmentalized using 0.2-μl Anopore membranes. The biofilms on polystyrene plates were harvested, and the solubilized proteins were separated by 2-DE. When S. mutans biofilms were formed in the presence of S. gordonii, the peroxide resistance protein Dpr of the former showed 4.3-fold increased expression compared to biofilms that developed in the absence of the pioneer colonizer. In addition, we performed a competition assay using S. mutans antioxidant protein mutants together with S. gordonii and other initial colonizers. Growth of the dpr-knockout S. mutans mutant was significantly inhibited by S. gordonii, as well as by S. sanguinis. Furthermore, a cell viability assay revealed that the viability of the dpr-defective mutant was significantly attenuated compared to the wild-type strain when co-cultured with S. gordonii. Therefore, these results suggest that Dpr might be one of the essential proteins for S. mutans survival on teeth in the presence of early colonizing oral streptococci.
authors: Department of Oral Microbiology, Matsumoto Dental University, Shiojiri, Japan; Division of Community Oral Health Science, Department of Oral Health Promotion, Kyushu Dental University, Kitakyushu, Japan.
authors: Akihiro
authors: A
authors: Yoshida
authors: Department of Bacteriology, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors: Mamiko
authors: M
authors: Niki
authors: Department of Animal Science, School of Veterinary Medicine, Kitasato University, Towada, Japan.
authors: Yuji
authors: Y
authors: Yamamoto
authors: Division of Community Oral Health Science, Department of Oral Health Promotion, Kyushu Dental University, Kitakyushu, Japan.
authors: Ai
authors: A
authors: Yasunaga
authors: Division of Community Oral Health Science, Department of Oral Health Promotion, Kyushu Dental University, Kitakyushu, Japan.
authors: Toshihiro
authors: T
authors: Ansai
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D018441:Biofilms; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D006801:Humans; D040901:Proteomics / Q000379:methods*; D054773:Streptococcus gordonii / Q000254:growth & development*; D013295:Streptococcus mutans / Q000502:physiology*; D014070:Tooth / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins