目的 检测变形链球菌不同毒力株的致龋性与磷酸转移酶(pts)系统各编码基因表达变化的关系.方法 选取高毒力株临床分离株502与低毒力株标准株UA159,以real-time PCR方法检测在1%和2%蔗糖浓度下,变形链球菌磷酸转移酶系统各编码基因的表达变化.结果 1%蔗糖浓度,高毒力株和低毒力株的scrA、scrB、ptsH、ptsI的表达均明显升高,而ptsK的表达受到抑制;2%蔗糖浓度,各基因的调节方向与上述相反.结论 磷酸转移酶系统可能增加变形链球菌在低糖浓度环境下的致龋力.%Objective To determine the expression level of genes which code pts under various conditions in different strains of S. Mutans. Methods S. Mutans of clinical isolations with different EPS producibility and UA159 were selected. Under 1% sucrose and 2% sucrose, the relative quantity of scrA, scrB,ptsI,ptsH and ptsK's mRNA of the two strains were examined by real-time PCR methods. Results In 1% sucrose, the expression levels of scrA,scrB ,ptsI,ptsH were increased in both strains, the level of ptsK was decreased. Expression levels of ptsH and ptsl were increased more in the strain with stronger virulence. In 2% sucrose the expression levels of scrA scrB ptsI ptsH were decreased the level of ptsK was increased in both strains. Conclusion PTS strengthened the cariogenicity of S. Mutans in low sucrose condition.
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