Sequence and analysis of O-antigen gene cluster in Escherichia coli O_(139,142,26)

The O-antigen gene of Escherichia coli O139,142,26 was amplified by the shotgun method,which was isolated in the mesenteric lymph node from a dead pig due to the edema disease.The sequencing results showed that the length of O-antigen gene was 11 771 bp.Ten open reading frames and their functions were found and predicted by bioinformatics methods.By comparing with the O-antigen gene sequences and the structure of glycosyl chain among the Escherichia coil.O139,O142 and O26,analyzing the phylogenetic tree,transmembrane protein structure and the process of adding acetyl to lactose precursors(Glc),the results indicated that the Escherichia coli O139,142,26 and the Escherichia coli O139 had a close evolutionary relationship of O-antigen gene.