【摘要】 目的检测具有不同产细胞外多糖能力的变形链球菌株,在不同培养条件下产细胞外多糖的能力及与gtfA、B、C、D表达变化的关系。方法选取变形链球菌高产糖与低产糖的临床分离菌株各10株及标准菌株UA159,用蒽酮法分别检测在1%、2%蔗糖培养下产细胞外多糖的能力;再用real-time PCR方法检测这些条件下与变链产糖能力密切相关的毒力因子葡萄糖基转移酶A、B、C、D的表达变化。结果蔗糖能诱导各菌株产生细胞外多糖。不同蔗糖浓度,高产糖菌株葡萄糖基转移酶A、B、C、D的表达均高于低产糖菌株。1%蔗糖浓度下,高产糖株与低产糖株葡萄糖基转移酶A、B、C、D表达均有不同程度升高。2%蔗糖浓度下,低产糖株gtfB、C、D表达均不同程度降低,葡萄糖基转移酶A略有升高,而高产糖株葡萄糖基转移酶A、B、D表达升高,仅葡萄糖基转移酶C略有降低。结论变形链球菌葡萄糖基转移酶的表达水平和产生细胞外多糖的能力受蔗糖浓度的影响。更多还原

【Abstract】 Objective To determine the expression level of each gtf under various conditions and its relationship with the ability to produce extracellular polysacchradides(EPS) in different strains of S.mutans. Methods Twenty strains of S.mutans of clinical isolations with different EPS producibility and UA159 were selected,and their ability to produce EPS under 1% sucrose and 2% sucrose were tested.Then in two strains,the relative quantity of gtfA,B,C,D’s mRNA were examined by real-time PCR methods. Results In all strains,the quantity of EPS was prominently enhanced by sucrose.The expression levels of gtfA,B,C,D were increased in 1% sucrose in both strains.In 2% sucrose,the expression levels of gtfB,C,D were decreased and gtfA was increased in the strain which produced less EPS.gtfB,D were decreased and gtfA,C were increased in the strain which produced more EPS. Conclusion The expression level of gtfs from S.mutants and its ability to produce extracellular polysaccharides were influenced by sucrose concentration.更多还原