full sequence and comparative analysis of the plasmid papec-1 of avian pathogenic e. coli χ7122 (o78∶k80∶h9)完整的序列和比较分析禽致病性大肠杆菌的质粒papec-1χ7122(o78∶k80∶h9).pdfVIP

Full Sequence and Comparative Analysis of the Plasmid pAPEC-1 of Avian Pathogenic E. coli x7122 (O78:K80:H9) 1 2 1,2 Melha Mellata , Jeffrey W. Touchman , Roy Curtiss III * 1The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America, 2 School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America Abstract Background: Extra-intestinal pathogenic E. coli (ExPEC), including Avian Pathogenic E. coli (APEC), are very diverse. They cause a complex of diseases in Human, animals, and birds. Even though large plasmids are often associated with the virulence of ExPEC, their characterization is still in its infancy. Methodology/Principal Findings: We fully sequenced and analyzed the large plasmid pAPEC-1 (103,275-bp) associated with the APEC strain x7122, from worldwide serogroup O78:K80:H9. A putative virulence region spanning an 80-kb region of pAPEC-1 possesses four iron acquisition systems (iutA iucABCD, sitABCD, iroBCDN, and temperature-sensitive hemagglutinin tsh), a colicin V operon, increasing serum sensitivity iss, ompT, hlyF, and etsABC. Thirty three ORFs in pAPEC-1 are identified as insertion sequences (ISs) that belong to nine families with diverse origins. The full length of the transfer region in pAPEC-1 (11 kb) is shorter compared to the tra region of other sequenced F plasmids; the absence of some tra genes in pAPEC-1 affects its self-transferability, and the conjugative function of the plasmid was effective only in the presence of other plasmids. Two-replicon systems, repFIIA-repFIC and repFIB, and two post-segregational systems, srnB and hok/sok, are also present in the sequence of pAPEC-1. The com