Mutational and transcriptional analyses of an avian pathogenic Escherichia coli ColV plasmidReportar como inadecuado




Mutational and transcriptional analyses of an avian pathogenic Escherichia coli ColV plasmid - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

BMC Microbiology

, 8:24

First Online: 29 January 2008Received: 16 July 2007Accepted: 29 January 2008

Abstract

BackgroundPreviously we described a 184-kb ColV plasmid, pAPEC-O2-ColV, that contributed to the ability of an E. coli to kill avian embryos, grow in human urine, and colonize the murine kidney. Here, the roles of several genes encoded by this plasmid in virulence were assessed using mutational and transcriptional analyses.

MethodsGenes chosen for deletion were iss, tsh, iutA, iroN, sitA, and cvaB. In addition, a 35-kb region of the plasmid, containing iss, tsh, and the ColV and iro operons, along with a 15-kb region containing both the aerobactin and sit operons, were deleted. Mutants were compared to the wild-type APEC O2 for lethality to chick embryos and growth in human urine. Expression of the targeted genes was also assessed under these same conditions using RT-PCR

ResultsNo significant differences between the mutants and the wild-type in these phenotypic traits were detected. However, genes encoding known or predicted iron transport systems were up-regulated during growth in human urine, as compared to growth in LB broth, while iss, hlyF, and iroN were strongly up-regulated in chick embryos.

ConclusionWhile no difference was observed between the mutant strains and their wild-type parent in the phenotypic traits assayed, we reasoned that some compensatory virulence mechanism, insensitivity of the virulence assays, or other factor could have obscured changes in the virulence of the mutants. Indeed we found several of these genes to be up-regulated in human urine and-or in the chick embryo, suggesting that certain genes linked to ColV plasmids are involved in the establishment of avian extraintestinal infection.

Jerod A Skyberg, Timothy J Johnson contributed equally to this work.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2180-8-24 contains supplementary material, which is available to authorized users.

Jerod A Skyberg, Timothy J Johnson contributed equally to this work.

Download fulltext PDF



Autor: Jerod A Skyberg - Timothy J Johnson - Lisa K Nolan

Fuente: https://link.springer.com/article/10.1186/1471-2180-8-24







Documentos relacionados