【摘要】 目的研究变形链球菌临床分离株耐酸因子F-ATPase亚基c、a、b联合基因uncEBF的遗传多态性,并探讨基因多态与细菌耐酸力的关系。方法选取18株变形链球菌高耐酸株、20株低耐酸株,以特异引物从细菌组DNA扩增uncEBF,行限制性内切酶长度多态性分析(RFLP)和测序比较。结果不同限制性内切酶RFLP产生不同的基因型,测序证实了导致多态出现的基因变异;其中内切酶AluⅠ产生的A、B基因型在不同耐酸力菌株的分布不同(P<0.05),高耐酸性菌株中A型基因uncEBF的检出高于低耐酸力菌株。结论变形链球菌F-ATPase亚基联合基因uncEBF具有明显基因多态性,酸性环境下生存力强的菌株可能出现基因的适应性变异,可认为不同基因型uncEBF分布与耐酸力不同相关。更多还原

【Abstract】 Objective The purpose of this research was to study the genetic diversity of F-ATPase subunit gene uncEBF derived from Streptococcus mutans(S.mutans) clinical isolates, furthermore to investigate the relationship between the genetic diversity of F-ATPase and S.mutans aciduric ability. Methods 38 S.mutans strains included 18 high acid tolerance strains and 20 low acid tolerance strains. Gene uncEBF of these isolates were amplified with specific primers from S.mutans genomic DNA, and the PCR products were analyzed by RFLP and sequenced. SPSS 11.0 statistic software assayed the results. Results It was testified that two genotypes A and B of PCR-RFLP were revealed when digested with AluⅠand DdeⅠdigested fragments of uncEBF displayed two different patterns C and D. Fisher exact two-tail test showed that the distributions of A and B genotype strains with different acidurance were different(P<0.05), and the proportion of A genotype strains from high acidurance group was higher than that from low acidurance one. Some of these amplified uncEBF genes from different genotype were sequenced and testified that there existed variation of AluⅠand DdeⅠrecognized sites. Conclusion This study indicated that uncEBF gene of S.mutans F-ATPase obviously exhibited genetic diversity.更多还原