【摘要】 克隆并分析禽病原性大肠杆菌(avian pathogenic Escherichia coli,APEC)部分毒力基因,探寻APEC毒力因子的变异和进化发生关系。以APEC中国分离株为模板,PCR扩增其部分毒力基因(fimC,kpsM,csgA,papC,felA,cvaC,iss),并测定了这些毒力基因扩增片段的核苷酸序列,与GenBank中的同一基因进行序列比较。PCR扩增产物经克隆、酶切鉴定,均与预期结果一致,序列分析结果表明上述毒力因子在APEC中的保守性非常高,均能达到99%以上。与其他来源大肠杆菌的同一基因的同源性也非常高,但不同基因间有所差别。APEC分离株的受试部分毒力因子的变异程度非常小,保守性很高,一些毒力因子与人源致肠外感染大肠杆菌的毒力因子同源性也很高,说明APEC与人源致肠外感染大肠杆菌的亲缘关系很近。更多还原

【Abstract】 The study was to clone and analyse related genes of pathogenic Escherichia coli isolates of chicken origin from some regions in China. Selected genes of APEC were amplified by PCR(fimC,kpsM,csgA,papC,felA,cvaC,iss). The PCR products were inserted into the T vector PCR2.1,respectively. The recombinant plasmids were identified by restriction endonuclease analysis and each gene was sequenced. Nucleotide sequences showed that genes mentioned above among APEC isolates were highly conservative and exibited about ninety percent similarity to those of the same genes of Escherichia coli from other sources. It revealed that the selected genes related to virulence in APEC were closed to those of the human extrointestinal Escherichia coli.更多还原