荚膜聚合酶Wzy对猪链球菌Chz型致病力的影响

Oligosaccharide repeat unit polymerase Wzy affects the pathogenicity in Streptococcus suis serotype Chz

[目的]本文旨在研究荚膜聚合酶Wzy对猪链球菌Chz型致病力的影响。[方法]通过基因组可视化软件(ACT)和比较基因组学方法,探究猪链球菌荚膜(CPS)基因簇的遗传多样性;构建cpsB及wzy基因缺失株,利用透射电子显微镜(TEM)研究Wzy与荚膜合成的关系;采用细胞试验及动物试验等验证荚膜聚合酶Wzy对细菌致病力的影响。[结果]与野生株相比,wzy基因缺失株荚膜样物质减少并展现出更强的生物被膜形成能力。细胞试验显示,缺失株具有更强的小鼠脑微血管内皮细胞(bEnd.3)黏附能力和侵袭能力,但对小鼠巨噬细胞(RAW264.7)的吞噬作用更敏感。BALB/c小鼠攻毒试验结果表明,缺失株的致病力显著减弱,在小鼠体内的定殖和扩散能力也明显下降。[结论]荚膜聚合酶Wzy降低猪链球菌的致病力。

[Objectives]This study aims to investigate the role of oligosaccharide repeat unit polymerase Wzy on the pathogenicity of Streptococcus suis serotype Chz.[Methods]The genetic diversity of S.suis capsular polysaccharides(CPS)gene cluster was explored by ACT comparative genomics method.The gene wzy and cpsB mutant strains were then constructed respectively,and the CPS thickness was identified by TEM.The cell and animal experiments were applied to verifing the effects of Wzy on bacterial pathogenicity.[Results]The mutant strain exhibited the reduced capsular-like substance and a stronger biofilm-forming ability compared with the wild-type strain.Cell experiments showed that the mutant strain had stronger adhesion to mouse brain microvascular endothelial cells(bEnd.3),while was more sensitive to the phagocytosis of mouse macrophages RAW264.7.In addition,the deletion of gene wzy significantly attenuated the bacterial pathogenicity and proliferation in vivo.[Conclusions]Polymerase Wzy affects the pathogenicity of Streptococcus suis.