肺炎链球菌感受态的形成影响毒力因子mRNA的表达

目的：通过体外实验诱导的转化过程，探索肺炎链球菌（Streptococcus pneumoniae,S.pn)毒力因子的表达是否与环境诱导细菌感受态形成与转化有关。方法：采用插入失活的方式断裂S.pn感受态形成的关键基因comE，获得感受态缺陷菌株。以实时定量RT－PCR测定毒力因子在感受态缺陷菌与野生菌的表达是否存在差异。所测毒力因子有自溶酶、溶血素、胆碱结合蛋白、S-IgA、神经氨酸酶、透明质酸酶。结果：S.pn在540nm处吸光度（A）值＝0.044－0.127之间产生感受态。自溶酶、神经氨酸酶、透明质酸酶3种毒力因子的表达，野生菌组表达高于缺陷菌组，两均数间比较的t值分别为2．96（P＜0．05）、2．8（P＜0．05）、4．56（P＜0．05）。结论：细菌感受态能启动自溶酶、神经氨酸酶、透明质酸酶3种毒力因子的表达，提示S.pn的感受态能影响其毒力因子的表达。

Investigation of competence-induced virulence of Streptococcus pneumoniae

Objective To induce the competence of Streptococcus pneumoniae( S.pn ) by an experiments in vitro and during the competence and to explore whether competence plays a role in the expression of virulence. To find if under certain in vitro circumstances the competence of S.pn can be induced. Methods (1) Competence was induced in the S.pn from clinic sample and created the mutants by insertion-duplicating the comE which is regarded as a key gene in competence establishing. (2) Use the real-time RT-PCR to test the expressing level of virulence in both the mutants and the wild type. Results Competence could be induced in vitro at A 540 nm=0.044-0.127 and the expressing level of three virulence, factors LytA, NanA, Hy were higher in wild type than in the come mutant ( P <0.05). Conclusion Competence can accelerate the expression of three virulence factors in S.pn , so it is regarded an important factor in disease causing by S.pn . [