Project description:To further explore potential molecular mechanisms and pathways by which the presence or absence of the pGKT2 plasmid may be affecting the overall fitness cost in the native Gordonia sp KTR9 strain, transcriptome studies were performed. Transcriptome experiments comparing KTR9 wild-type and mutant strains grown in rich media confirmed the loss of the pGKT2 plasmid and also indicated the loss of the 90 kb pGKT1 plasmid.
Project description:To further explore potential molecular mechanisms and pathways by which the presence or absence of the pGKT2 plasmid may be affecting the overall fitness cost in a transconjugant Rhodococcus jostii RHA1 strain, transcriptome studies were performed. Transcriptome experiments comparing RHA1 wild-type and RHA1 transconjugant strains grown in rich media confirmed the presence of the pGKT2 plasmid.
Project description:Test whether it is possible to conjugate a whole plasmid library into a recipient strain without loss of fidelity (as judged by aCGH analysis)
Project description:Related surrogate species are often used to study the molecular basis of pathogenicity of a pathogen on the basis of a shared set of biological features generally attributable to a shared core genome consisting of orthologous genes. An important and understudied aspect, however, is the extent to which regulatory features affecting the expression of such shared genes are present in both species. Here we report on an analysis of whole transcriptome maps for an important member of the TB complex Mycobacterium bovis and a closely related model organism for studying mycobacterial pathogenicity Mycobacterium marinum.
Project description:Many species of pathogenic bacteria harbor critical plasmid-encoded virulence factors, and yet the regulation of plasmid replication is often poorly understood despite playing key role in plasmid-encoded gene expression. Human pathogenic Yersinia, including the plague agent Yersinia. pestis and its close relative Y. pseudotuberculosis, require the type III secretion system (T3SS) virulence factor to subvert host defense mechanisms and colonize host tissues. The Yersinia T3SS is encoded on the IncFII plasmid for Yersinia virulence (pYV). Several layers of gene regulation enables a large increase in expression of Yersinia T3SS genes at mammalian body temperature. Surprisingly, T3SS expression is also controlled at the level of gene dosage. The number of pYV molecules relative to the number of chromosomes per cell, referred to as plasmid copy number, increases with temperature. The ability to increase and maintain elevated pYV plasmid copy number, and therefore T3SS gene dosage, at 37˚C is important for Yersinia virulence. In addition, pYV is highly stable in Yersinia at all temperatures, despite being dispensable for growth outside the host. Yet how Yersinia reinforces elevated plasmid replication and plasmid stability remains unclear. In this study, we show that the chromosomal gene pcnB encoding the polyadenylase PAP I is required for regulation of pYV plasmid copy number (PCN), maintenance of pYV in the bacterial population outside the host, robust T3SS activity, and Yersinia virulence in a mouse infection model. Likewise, pcnB/PAP I is also required for robust expression of the Shigella flexneri virulence plasmid-encoded T3SS that, similar to Yersinia, is encoded on a virulence plasmid whose replication is regulated by sRNA. Furthermore, Yersinia and Shigella pcnB/PAP I is required for maintaining normal PCN of model antimicrobial resistance (AMR) plasmids whose replication is regulated by sRNA, thereby increasing antibiotic resistance by ten-fold. These data suggest that pcnB/PAP I contributes to the spread and stabilization of sRNA-regulated virulence and AMR plasmids in bacterial pathogens, and is essential in maintaining the gene dosage required to mediate plasmid-encoded traits. Importantly pcnB/PAP I has been bioinformatically identified in many species of bacteria despite being studied in only a few species to date. Our work highlights the potential importance of pcnB/PAP I in antibiotic resistance, and shows for the first time that pcnB/PAP I reinforces PCN andpromotes virulence plasmid stability in natural pathogenic hosts with a direct impact on bacterial virulence.