EHECO157∶H7stx基因缺失突变株的构建及其特性  

Construction of a stx Deletion Mutant of EHEC O157∶H7

作　　者：孙洋[1] 刘军[1] 郭学军[1] 常国权[1] 尹铁勇[1] 冯书章[1] 

机构地区：[1]解放军军需大学军事兽医研究所,吉林长春130062

出　　处：《中国兽医学报》2005年第2期166-169,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：针对肠出血性大肠杆菌 (EHEC) O1 5 7∶H7的 stx基因 ,通过 PCR扩增出缺失了 1 83bp的 stx基因片段 ,将其克隆到自杀性载体 p CVD4 4 2中 ,然后通过接合性转导将重组自杀性质粒 p CVD4 4 2∷Δstx从大肠杆菌 SM1 0转到 O1 5 7∶ H7中 ,利用抗性标记和 PCR方法筛选出 O1 5 7∶ H7stx基因缺失突变菌株。Vero细胞毒性试验证实 ,该突变株不能产生完整的 Stx。动物试验表明 ,与强毒株相比该突变株的致病性明显降低。该突变株的构建为研究志贺毒素在 EHEC O1 5 7感染中所起的作用和研制 O1 5In order to determine the effect of stx gene of EHEC O157∶H7, stx deletion mutant was constructed.Δstx gene was amplified by PCR and cloned into a suicide vector pCVD442, which containing the pir-dependent R6K replicon and sacB gene. The recombinant plasmid pCVD442∷Δstx was transformed into a host cell SM10pir, then conjugated from SM10(pCVD442∷Δstx) into EHEC O157∶H7 86-24. Because a homologous recombination would take place between Δstx and stx which located on the chromosome, the strain of EHEC O157∶H7 stx deletion mutant was screened out. The study demonstrates that the stx deletion mutation results in loss of toxicity to vero cell, but some pathogenicity still remains. This study provides the foundation for construction of attenuated vaccine against EHEC O157.

关 键 词：肠出血性大肠杆菌 stx基因 基因缺失突变 致病性 自杀载体技术 表型 

分 类 号：S852.612[农业科学—基础兽医学]