一种溶菌酶样蛋白对肺炎链球菌毒力及荚膜多糖合成的影响

Influenceof lysozyme-like protein on virulence and capsular polysaccharide synthesis of Streptococcus pneumoniae

摘要:

摘要：【目的】为了研究肺炎链球菌（Streptococcus pneumoniae, S.pn）的一种假想的溶菌酶样蛋白在细菌生物学性状及其致病中的作用。【方法】利用长臂同源PCR对该基因进行敲出，并同时构建带有拯救质粒的缺失菌株，观察D39野生菌、缺失菌与带有拯救质粒的缺失菌株在相关生物学性状及其致病力改变，从而鉴定这种假想溶菌酶样蛋白的功能。【结果】缺失菌与野生菌相比，细菌生长减缓，毒力下降，荚膜多糖合成明显减少。而将拯救质粒转入缺失菌株后，该溶菌酶样蛋白的mRNA表达水平较野生菌高，其毒力及荚膜合成

Abstract:

Abstract：[Objective] To study the biological character and pathogenic effect of a lysozyme-like protein in Streptococcus pneumoniae. [Methods] The gene knockout mutant was constructed by the long flanking homology polymerase chain reaction. The mutant containing rescue plasmid to complement the lysozyme-like gene was also constructed. The differences in biology and pathogenicity in D39 wild strain, gene knockout mutant and gene knockout mutant containing rescue plasmid were observed to identify the functions of the lysozyme-like gene. [Results] Compared with the wild strain, the gene knockout mutant had the characteristics of slower growth, declining virulence, and obviously reduced capsule polysaccharide synthesis. Complement experiment showed when the rescue plasmid was transformed into the mutant strain, the mRNA level of hypothetical lysozyme-like gene in the gene knockout mutant containing rescue plasmid was higher than that of the wild strain .Although the levels of virulence and capsule polysaccharide synthesis could be partly complemented compared with those of the gene knockout mutant, but not reached the levels in the wild strain. [Conclusions] The lysozyme-like protein, a new Streptococcus pneumoniae virulence factor, may regulate the proliferation and the capsular polysaccharides synthesis of Streptococcus pneumoniae to affect expression of virulence.