维吾尔族不同龋敏感儿童变形链球菌临床分离株表面蛋白V区遗传多态性研究

Genetic diversity within the V-region of surface protein of Streptococcus mutans from different dental caries susceptible Uyghur children

目的比较维吾尔族高龋和无龋儿童变链菌临床分离株表面蛋白V区遗传多态性与其合成水不溶性葡聚糖的关系。方法选取课题组前期实验所得的维吾尔族高龋儿童合成水不溶性葡聚糖能力较强的变形链球菌临床株18株和无龋儿童合成水不溶性葡聚糖能力较弱临床株12株。提取全菌DNA,经PCR扩增其表面蛋白可变区V区编码基因SrV^+后,利用限制性内切酶DdeⅠ进行限制性片段长度多态性分析。结果经DdeⅠ酶切后,高产糖组变链菌出现了4种基因型,低产糖组出现了3种基因型。这几种基因型在不同产糖组中的分布不同(P<0.05)。结论维吾尔族不同龋敏感儿童变形链球菌临床分离株SrV^+基因的遗传多态性可能是其合成水不溶性葡聚糖能力出现差异的因素之一。

Objective To compare the genetic diversity within the V-regions of surface protein of Streptococcus mutans between caries-active and caries-free Uyghur children, and explore its relationship with the synthesis of insoluble glucans. Methods The isolates were collected from 18 caries-active Uyghur children harbored S. mutans strains producing high water-insoluble glucans and 12 caries-free children harbored the strains with low water-insoluble glucans. The genomic DNA was extracted, and the SrV＋ gene was ampli- fied by polymerase chain reaction （PCR） . Genetic diversity was assessed by restriction fragment-length pol- ymorphism （RFLP） with restriction endonucleases Dde I . Results The digestion with Dde I resulted in four genotypes in the high sugar-producing Streptococcus rnutans, and three genotypes in the low sugar-producing strains. These genotypes were distributed in different sugar groups （P〈0.05） . Conclusion Among different dental caries-susceptible Uyghur children, the genetic diversity within SrV＋ of clinical isolates of S. mutans might he related to the differences in the synthesis of insoluble glucans.