Functional analysis of signal transduction system involving membrane transporters in Streptococcus mutans

点击翻译按钮获取中文摘要

Streptococcus mutans metabolizes carbohydrates for adherence to and formation of biofilm on tooth surfaces, which allows the pathogen to tolerate rapid and frequent environmental fluctuations, such as nutrient availability, aerobic-to-anaerobic transitions, and pH changes. Investigation of ammonium transporters is important, as they play crucial roles in the uptake of nutrients by S. mutans in biofilm. The present study focused on characterizing the SMu1510 gene corresponding to nrgA in S. mutans, which is homologous to the ammonium transporter gene in Bacillus subtilis. The growth rate of an nrgA-deficient mutant strain (NRGD) was lower than that of the parental strain in the presence of ammonium. In addition, confocal laser scanning microscopy revealed that the structure of biofilm formed by NRGD was drastically different as compared to formed by the parental strain. These results suggest that the nrgA gene in S. mutans is essential for export of molecules and biofilm formation.