肠出血性大肠杆菌O157ler基因缺失突变株的构建及其特性  

Construction and characterization of EHEC O157∶H7 ler gene deletion mutant

作　　者：孙洋[1] 刘军[1] 郭学军[1] 张勇[2] 祝令伟[1] 周博[1] 冯书章[1] 

机构地区：[1]军事医学科学院军事兽医研究所,吉林长春130062 [2]空军航空大学特种专业系,吉林长春130000

出　　处：《中国兽医学报》2008年第11期1269-1272,共4页Chinese Journal of Veterinary Science

基　　金：国家自然科学基金资助项目(30270985)

摘　　要：以肠出血性大肠杆菌O157∶H786～24为始发菌株,利用自杀性载体pCVD442,根据同源重组的原理敲除了染色体上的ler基因,构建了O157∶H7 ler基因缺失突变菌株,并对其生物学特性进行了初步研究。荧光定量PCR试验结果表明,始发菌株对HEp-2细胞的平均黏附数量是突变菌株的17倍。试验也证实了ler基因对LEE致病岛毒力基因的正调控作用,这为O157∶H7基因缺失突变弱毒疫苗株的建立奠定了基础。One of the important virulence traits of enterohemorrhagic Escherichia coli （EHEC） O157 ： H7 is capable to produce attaching and effacing （A/E） lesions on enterocyte. This property encoded by a pathogenicity island （PAI） termed the locus of enterocyte effacement （LEE）. In this study,a let （LEE-encoded regulator） deletion mutant of O157 ： H7 was constructed by using suicide vector pCVD442. Adherence of the mutants to HEp-2 cells was diffuse with few intimate attachments whereas wild-type bacteria formed more microcolonies. The date of fluorescent quantitation PCR showed that the mutants quantity of adhere to HEp-2 cell reduced 17 times than wild-type bacteria. These results confirm that ler gene is necessary for adherence but additional adherence factors are involved in adherence. These studies provide a foundation for construction of a mutant attenuated vaccine strain against EHEC O157 ： H7.

关 键 词：肠出血性大肠杆菌O157:H7 ler基因 缺失突变 

分 类 号：S852.61[农业科学—基础兽医学] S855.99[农业科学—兽医学]