Abstract:

Abstract:Objective To detect the mutation of  acid-resistant gene gluA in the fluoride-resistant strain of streptococcus mutans and clarify the  acid-resistant change of fluoride-resistant strain.  Methods Streptococcus mutans were artificially induced  into fluoride-resistant strain of streptococcus mutans in vitro.The genome of fluoride- resistant strain of streptococcus mutans was obtained by  alkaline method;in accordance with  primer design principles,according to the published GenBank sequence of streptococcus mutans gluA, a pair of  primers were designed  for PCR.The PCR products were cloned into pMD18-T vector and the recombinant plasmid was constructed.The insertion fragment was identified with restrictive enzyme and sequenced. Results By BLASTN comparison,the sequence of  acid-risistant gene gluA of the fluoride-resistant strain of streptococcus mutans was the same with that reported in GenBank. Conclusion The acid-resistant gene gluA of the fluoride-resistant strain of streptococcus mutans has not been any mutation which has no impact on the acid-resistant character of fluoride-resistant strain of streptococcus mutans.

Key words: streptococcus mutans；fluoride-resistant strain；acid-resistant gene gluA;recombinant plasmid;gene mutation