The Sequence Analysis And Research In Immunogenicity Of The Prokaryotic Expression Product Of PilA Gene Of Pathogenic E.coli Isolated From Ducks

According to the published pilA gene sequence of human Escherichia coli from GenBank,using the software of Oligo6.0, a pair of primers were designed and synthesized. The duck pathogenic Escherichia coli positive by MSHA detection, the genomic DNA of which were extracted and used as templates to amplify the pilA gene by PCR, then the products were sequenced and analyzed by bioinformatics;the pilA gene had also been expressed by prokaryotic expression and had the immunogenicity detected.The results were as follows:185 strains of pathogenic E.coli isolated from ducks were detected by MSHA, and the positive rate was 65.9% (122/185) ; 25 strains of the MSHA positives were chosed toamplify the pilA gene by PCR, 21 strains were positive and the positive rate was 84%.The pilA gene of 5 strains ( GH1.2,CY1.3,EM2.5,SL3.2,YL4.3 ) were sequenced andanalyzed , and indicated that the specific amplicons were 549bp in length and encoded 182 amino acid. By comparison, the homology of Nucleotide and amino acid were 92.4%-100.0% and 92.9%-100% respectively among the pilA gene of ducks; 87.3%-99.8% and 87.5%-99.5% between the duck pilA genes and other isolates from chicken, pigs and human. The prediction and analysis of secondary structure, hydrophilicity , antigenicity and epitope of the pilA gene encoding protein from different isolates showed that they had some structure similarity between each other and they also had some common antigens. The phylogenetic tree showed that the pilA gene relationship between the genetic correlation of different strains and their host isolates was not so closely, nor was the serotype.