Objectives: The aim of this study is to clarify the correlations between colonial morphology and their glucan synthesis in wild types and their mutants of
Streptococcus mutans. The expression of their mRNA of three
gtfs were quantitatively examined and compared.
Methods: Ten smooth colony mutants from 4
S. mutans were isolated. The glucan synthesis and sucrose dependent artificial plaque formation abilities compared with wild types were examined. Total RNA were extracted from late logarithmic phase cells. The quantitative analysis of expression of three
gtfs (
gtfB, gtfC, and
gtfD) were performed with reverse transcription and real-time PCR using SYBR Green dye. The amount of expressions of three gtfs were normalized against housekeeping gene and compared with wild types and their mutants.
Results: Glucan syntheses of all mutants were negligible compared with those of wild types. Although wild types adhered to the glass surface tightly, the results of sucrose dependent artificial plaque formations of mutants were diverse. There were no differences of the expressions of
gtfB and
gtfD between wild types and mutants. Moreover, the expressions of
gtfC from wild types were similar among them, however those from mutants were not detected.
Conclusions: The expressions of
gtfc might beplay an important role in smooth colony formation. However the mechanism of colonial morphology formation and adhesion to hard surfaces might be difference. This work was supported in part by Grant-in-aid-for Scientific Research from the Ministry of Education, Scienceand Culture of Japan (16592096).