致犊牛脑膜炎大肠杆菌新疆分离株ibeB基因的特性分析  

Characterization of ibeB gene of meningitic Escherichia coli strains in calves from Xinjiang

作　　者：凌晨[1] 蒋建军[1] 宋康[1] 张坤[1] 师燕霞 冯广余 倪宏斌[1] 朱玲[1] 王鹏雁[1] 剡根强[1] 

机构地区：[1]石河子大学动物科技学院,新疆石河子832000

出　　处：《微生物学报》2016年第6期974-982,共9页Acta Microbiologica Sinica

基　　金：国家科技支撑计划(2012BAD43B02)~~

摘　　要：【目的】分析致犊牛脑膜炎大肠杆菌分离株ibeB基因的分子生物学信息。【方法】以自脑炎死亡犊牛脑组织、肝组织分离鉴定的O161-K99-STa致病性大肠杆菌牛-EN株和牛-EG分离株为材料。根据GenBank中公布的脑膜炎大肠杆菌K1株RS218 ibeB基因序列设计1对引物,采用PCR方法,从分离株中成功克隆ibe B基因,比较分离株ibeB基因与不同来源大肠杆菌ibeB基因的部分生物信息学特性。【结果】分离株ibeB基因序列全长1500 bp,包含1371 bp开放阅读框,共编码457个氨基酸;生物信息学分析显示,牛-EN株与致人脑膜炎大肠杆菌K1 RS218的核苷酸和氨基酸同源性分别为90.5%和96.9%,牛-EG株与大肠杆菌K12的核苷酸和氨基酸同源性分别为99.4%和100.0%;ibeB蛋白为亲水性蛋白,分子质量为50.26 kDa,理论等电点为6.05;该蛋白无跨膜区,但具有信号肽序列;亚细胞定位显示,分泌信号通路位点(SP)占比例为0.939,说明该蛋白属于分泌型蛋白。【结论】从致脑膜炎大肠杆菌分离株中成功克隆ibeB基因,该基因与致人脑膜炎大肠杆菌K1 RS218 ibeB基因有较高的同源性,均有相似的生物学特性,属肠外致病性大肠杆菌。[Objective] To understand the molecular biology information of ibeB gene of meningitic Escherichia coli isolates in calves. [Methods] The strain used was isolated from the brain and liver tissue of calves died from Meningitis. It was identified to be an O161-K99-STa pathogenic Escherichia coli strain and named as bovine-EN and bovine-EG. Based on the sequence of ibeB gene of meningitic Escherichia coli K1 RS218 strain in Gen Bank, a pair of primers was designed and the ibeB gene was cloned from isolates by PCR. Part molecular biology information of ibeB among different strains was compared. [Results] The sequence length of isolates ibeB gene was 1500 bp, containing a1371 bp open reading frame（ORF） encoding 457 amino acids. Bioinformatics analysis showed that the nucleotide and amino acid homology of ibeB gene of bovine-EN strain shared 90.5% and 96.9% identity with Escherichia coli K1RS218 ibeB gene, respectively, while bovine-EG strain shared 99.4% and 100.0% identity with Escherichia coli K12 respectively. The ibeB gene of bovine- E strains encoded water-soluble protein whose molecular weight was 50.26 k Da and isoelectric point was 6.05. This protein contained a signal peptide A but no transmembrane domain.Subcellular localization of ibeB belonged to the secreted protein, which secretory signal path site（SP） proportion was0.939. [Conclusion] The ibeB gene was cloned from meningitic E. coli isolates and had higher homology and similar biological characteristics with meningitis E. coli K1 RS218 ibeB, which belongs to extraintestinal pathogenic Escherichia coli.

关 键 词：脑膜炎 大肠杆菌 ibeB 克隆 生物信息学分析 

分 类 号：S852.61[农业科学—基础兽医学]