假想的脂蛋白连接酶对肺炎链球菌毒力的影响

【目的】探索假想脂蛋白连接酶(putative lipoate-protein ligase,LPL)对肺炎链球菌毒力的影响。【方法】采用长臂同源多聚酶链式反应(LFH-PCR)的方法失活lpl基因,通过PCR、测序鉴定缺陷菌株,采用细胞实验比较缺陷菌和野生菌对宿主细胞的粘附能力,并通过动物实验观察lpl基因缺陷后菌株毒力的变化。【结果】小鼠毒力实验表明野生菌株和缺陷株半数致死时间均为12h,两者比较无统计学差异;缺陷菌在对宿主细胞的粘附能力明显高于野生菌株(P0.01);体外荚膜染色实验表明,野生菌和缺陷菌均有荚膜。【结论】实验结果提示lpl基因对细菌粘附宿主细胞有抑制作用,但不影响其腹腔感染小鼠的能力。

Contributions of putative lipoate-protein ligase to the virulence of Streptococcus pneumoniae

Abstract: Objective] To investigate the effect of putative lipoate-protein ligase (LPL) on the virulence of Streptococcus pneumoniae. Methods] lpl gene deficient strain was constructed by LFH-PCR and identified by PCR and sequencing. The cell adherence assay and mice challenge assay were used to observe the differences between wild strain and the mutant in the pathopoiesis of Streptococcus pneumoniae. Results] Mice virulence experiments showed that the median lethal time of wide type and the lpl mutant are both 12h, no statistics difference ;The ability of adherence of the mutant was greater than the wild strain( P < 0.01); The capsule stain in-vivo showed that the wild strain and the mutant both had the capsule. Conclusion] lpl gene inhibits the adherence to host, but no affect on the ability to infection mice by intraperitoneal injection.