Project description:Avian pathogenic Escherichia coli strains frequently cause extra-intestinal infections and are responsible for significant economic losses in the poultry industry worldwide. APEC isolates are closely related to human extraintestinal pathogenic E.coli strains and may also act as pathogens for humans. In this work, three type VI secretion systems were deleted to analyze which pathogenicity characteristics would change in the mutants, compared to wild type strain (SEPT 362).
Project description:Avian pathogenic Escherichia coli strains frequently cause extra-intestinal infections and are responsible for significant economic losses in the poultry industry worldwide. APEC isolates are closely related to human extraintestinal pathogenic E.coli strains and may also act as pathogens for humans. In this work, three type VI secretion systems were deleted to analyze which pathogenicity characteristics would change in the mutants, compared to wild type strain (SEPT 362). Four Avian Pathogenic Escherichia coli strains (one wild type and three deleted mutants) were grown at 37°C in Dulbecco´s Modified Eagle´s Media (DMEM) media until reach O.D 600 = 0.8, for RNA extraction and hybridization on Affymatrix microarrays.
Project description:DNA microarray-mediated transcriptional profiling of avian pathogenic Escherichia coli O2 strain E058 during its infection of chicken
Project description:Colisepticemia caused by avian pathogenic Escherichia coli (APEC) results in annual multimillion dollar losses to the poultry industry. Recent research suggests that APEC may have an important role in public health as well. Generally, colisepticemia follows a respiratory tract infection in which APEC penetrate the respiratory epithelium to enter the bloodstream. From the bloodstream, bacteria may spread to various internal organs resulting in perihepatitis, pericarditis, and other conditions. The aim of this study was to identify molecular mechanisms enabling APEC to survive and grow in the bloodstream. To do so, we compared the transcriptome of APEC O1 during growth in Luria-Bertani broth and chicken serum. Selected genes that were significantly up-regulated in chicken serum were then subjected to mutational analysis to confirm their role in APEC pathogenesis. Several categories of genes, predicted to contribute to adaptation and growth in the avian host, were identified. These included several known virulence genes and genes involved in adaptive metabolism, protein transport, biosynthesis pathways, stress resistance, and virulence regulation. Several genes with unknown function, which were localized to pathogenicity islands or APEC O1’s large virulence plasmid, were also identified, suggesting that they too contribute to survival in chicken serum. This genome-wide analysis provides novel insight into processes that are essential to APEC O1’s survival and growth in chicken serum. Two-condition experiment: LB vs. chicken serm; four biological replicates, independently grown and harvested.
Project description:Many reports show an association between the Pst system, the Pho regulon related genes and bacterial virulence. Our previous results showed that a functional Pst system is required for full virulence, resistance to serum, polymyxin B and acid shock. However, the interplay between the Pst system and virulence has an unknown molecular basis. To understand global APEC virulent strain responses to Pho regulon activation, we conducted transcriptome profiling experiments comparing the APEC chi7122 strain and its isogenic Pst mutant grown in rich phosphate medium using the Affymetrix GeneChip® E. coli Genome 2.0 Array. The Affymetrix GeneChip® E. coli Genome 2.0 Array contains the genome of the E. coli MG1655 and three pathogenic E. coli strain (EDL933, Sakai and CFT073) representing 20,366 genes. While comparing genes expression between Pst mutant and the wild type chi7122 strain, 471 genes are either up- (254) or down-regulated (217) of at least 1.5-fold, with a p-value inferior or equal to 0.05 and a false discovery rate of 2.71%. Keywords: Escherichia coli, phosphate starvation response, Pho regulon, Pst system, Affymetrix, transcriptional analysis