Study On The Ability Of Acidogenicity、aciduricity And Genetic Diversity Within Aciduric Viruience Of Streptococcus Mutans From Caries-active And Caries-free Individuais In Urumqi Uygur Children

Objective: To investigate the acidogenicity and aciduric ability of Streptococcusmutans isolated from the Uyghur children with different caries susceptibility andstatus in Urumqi;and genetic diversity of F-ATPase subunit gene uncD and uncEBF.Methods:50S.mutans isolates Uyghur children wereinoculated in the media withdifferent pH values. The subtraction values before inoculation and after24h growth weremeasured and the densities of the cultures were determined. The acidogenie abilities andgrowth of these strains growing at different pH values were compared. In the second partof the experiment,33strains with different aciduric abilitie were chosen to grow in theBHI media, Gene uncEBF and uncD of these isolates PCR products were analyzed byRFLP. Results:1) The acidogenicity and aciduric ability of Streptococcus mutans isolatedfrom the high caries-susceptible Uyghur children and were significantly higher than thatisolated from caries-free group. The high cariogenecity of Streptococcus mutans strainsisolated from caries-active Uyghur children shows a close relationship with the highacidogenecity and aciduric ability of the isolated Streptococcus mutans strains.2)Six genotype uncD were revealed by AluⅠ-RFLP and HinfⅠ-RFLP,but the distributiondifferences of the A、B、C genotypes with different acidurance strains had no significance.D、E、F different aciduranc strains were shown difference.3) It is testified that twogenotypes A and B of PCR-RFLP were revealed when uncEBF Was digested withAluⅠ.The distributions of A and B genotype strains with different acidurance weredifferent, and the proportion of A genotype strains from high acidurance group was higherthan that from low acidurance one. Conclusion: It is thus evident that S.mutans F-ATPaseexsit obviously genetic diversity in genotype. This diversity characteristic is closelyassociated with the aciduric ability of S. mutans strains.