单核细胞增生性李斯特菌prfA基因缺失株的构建及其生物学特性  

Construction and characterization of Listeria monocytogenes ΔprfA mutant strains

作　　者：白春光[1] 殷月兰[1] 贾艳艳[1] 付红[1] 高云飞[1] 焦新安[1] 

机构地区：[1]扬州大学,江苏省人兽共患病学重点实验室,扬州225009

出　　处：《微生物学报》2011年第11期1555-1560,共6页Acta Microbiologica Sinica

基　　金：教育部“长江学者和创新团队发展计划”创新团队资助;国家支撑计划(2009BADB9B01);江苏高校优势学科建设工程资助项目~~

摘　　要：【目的】单核细胞增生性李斯特菌(Lm)是人兽共患李斯特菌病的病原菌,其致病性与调控因子PrfA蛋白作用下毒力基因的表达有着密切关系,本文初步探讨了PrfA蛋白对细菌毒力因子的调控作用。【方法】利用同源重组技术对血清型分别为1/2a和4b的LM4、F4636进行prfA基因的敲除,并构建其回复突变株,对获得的突变株LM4ΔprfA、F4636ΔprfA进行生物学特性研究。【结果】实验结果表明:两株缺失株的溶血活性丧失、回复突变株的溶血活性得到恢复,突变株还丧失磷脂酶活性,黏附和侵袭特性显著下降(P<0.05),对BALB/c小鼠的半数致死剂量提高了105个数量级。【结论】由此表明,PrfA蛋白对hly、plcB、inl家族基因的表达及细菌毒力具有重要的调控作用。prfA基因缺失株的构建为进一步研究PrfA蛋白的调控功能提供了材料,为研究其在Lm致病性中的作用奠定了基础。[Objective] Listeria monocytogenes（Lm） is an important pathogen that can cause serious listeriosis in humans and animals.The pathogenicity of Lm has a close relationship with the PrfA protein regulating the expression of virulence genes.Therefore,we studied the regulation functions of PrfA and its role on Lm＇s virulence.[Methods] The prfA genes of LM4,serotype 1/2a,and F4636,serotype 4b,were deleted by homologous recombination technology,and the biological characteristics of the mutants were further studied.[Results] The prfA gene deleted strains LM4ΔprfA and F4636ΔprfA and their back mutation strains were successfully constructed.The results show that the hemolysis activity was lost in prfA deleted strains and was recovered in the reverse mutant strains.The prfA deleted strains lost phospholipase activity;their adhesion and invasion ability significantly decreased.Furthermore,their 50% lethal doses（LD50） were 5 logs higher comparing with wild type strains.[Conclusion] PrfA regulates hly,plcB and inl gene family and affects significantly Lm＇s virulence.

关 键 词：单核细胞增生性李斯特菌 突变株 prfA基因 同源重组 生物学特性 

分 类 号：R378[医药卫生—病原生物学] S852.61[医药卫生—基础医学]