title: A novel gene involved in the survival of Streptococcus mutans under stress conditions.
abstract: A Streptococcus mutans mutant defective in aciduricity was constructed by random-insertion mutagenesis. Sequence analysis of the mutant revealed a mutation in gidA, which is known to be involved in tRNA modification in Streptococcus pyogenes. Complementation of gidA by S. pyogenes gidA recovered the acid tolerance of S. mutans. Although the gidA-inactivated S. pyogenes mutant exhibited significantly reduced expression of multiple extracellular virulence proteins, the S. mutans mutant did not. On the other hand, the gidA mutant of S. mutans showed reduced ability to withstand exposure to other stress conditions (high osmotic pressure, high temperature, and bacitracin stress) besides an acidic environment. In addition, loss of GidA decreased the capacity for glucose-dependent biofilm formation by over 50%. This study revealed that gidA plays critical roles in the survival of S. mutans under stress conditions, including lower pH.
authors.affiliation: Section of Preventive and Public Health Dentistry, Division of Oral Health, Growth and Development, Kyushu University Faculty of Dental Science, Fukuoka, Japan.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.forename: Yukie
authors.initials: Y
authors.lastname: Shibata
authors.forename: Toru
authors.initials: T
authors.lastname: Takeshita
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Yamashita
mesh_terms: D000143:Acids / Q000633:toxicity; D000900:Anti-Bacterial Agents / Q000378:metabolism; D001414:Bacitracin / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D004361:Drug Tolerance; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D050296:Microbial Viability; D016254:Mutagenesis, Insertional; D009997:Osmotic Pressure; D013295:Streptococcus mutans / Q000187:drug effects / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D013312:Stress, Physiological
chemical_list: D000143:Acids; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C108512:glucose-inhibited division protein A, bacteria; D001414:Bacitracin