大肠杆菌O54 O-抗原基因簇的破译及进化分析

破译了大肠杆菌O5 4O 抗原基因簇的序列 ,序列全长 1 4 0 6 2bp。用生物信息学方法分析序列并鉴定基因 ,共确定 1 0个基因 ,包括鼠李糖合成酶基因BDA和C(rmlBDA和rmlC) ,糖基转移酶基因 ,O 抗原转运酶基因 ,O 抗原聚合酶基因和合成磷酸丝氨酸侧链的基因及 1个不能确定功能的开放阅读框。对rmlC的 (G C) %含量 ,稀有密码子含量及进化分析都表明大肠杆菌O5 4O 抗原基因簇是在近期通过rmlC介导的重组形成 ,而且大肠杆菌O5 4和鲍氏志贺氏菌 9型的亲缘关系很近。对UTP 葡萄糖 1 磷酸 尿苷转移酶基因 (galF)和 6 磷酸葡萄糖脱氢酶基因(gnd)的进化分析揭示志贺氏菌属与大肠杆菌属在进化上属于同一个属。用PCR方法筛选出了针对大肠杆菌O5 4的特异基因 ,用于基因芯片或PCR方法对大肠杆菌O5 4的快速检测。

Sequence and Evolutional Analysis of Escherichia coli O54 O-antigen Gene Cluster

The Escherichia coli O54 O antigen gene cluster was sequenced. It was found to contain genes responsible for the biosynthesis of nucleotide sugar dTDP rhamnose ( rmlBDA and rmlC ), genes encoding O unit flippase( wzx ) and O antigen polymerase( wzy ) and putative transferase. Unlike most of the cases in which rml genes are located together, rmlC was apart from other rml genes. Further analysis indicated that rmlC gene was recently introduced into the O antigen gene cluster of Escherichia coli O54 It was also found that E.coli O54 and Shigella bodyii 9 are closely related. By polymerase chain reaction for the 166 E.coli and 43 Shigella O serogroups, wzx and wzy as specific genes for E.coli O54 were identified This work provides the basis for a sensitive test for the rapid detection of E.coli O54