Project description:Transcriptional profiles of uropathogenic Escherichia coli CFT073 exposed to cranberry-derived proanthocyanidins (PACs) were determined. Our results indicate that bacteria grown on media supplemented with PACs were iron-deprived. To our knowledge, this is the first time that PACs have been shown to induce a state of iron-limitation in this bacterium.
Project description:Here we dissected a regulatory network directed by the conserved iron homeostasis regulator, Ferric Uptake Regulator (Fur), in uropathogenic E. coli strain CFT073. Comparing anaerobic genome-scale Fur DNA binding, with Fur dependent transcript expression and protein levels of the uropathogen to that of commensal E. coli K-12 strain MG1655, showed that the Fur regulon of the core genome is conserved but also includes genes within the pathogenicity/genetic islands. Unexpectedly, regulons indicative of amino acid limitation and the general stress response were also indirectly activated in the uropathogen fur mutant, suggesting that induction of the Fur regulon increases amino acid demand. Using RpoS levels as a proxy, addition of amino acids mitigated the stress. In addition, iron chelation increased RpoS to the same levels as in the fur mutant. The increased amino acid demand of the fur mutant or iron chelated cells was exacerbated by aerobic conditions, which could be partly explained by the O 2 -dependent synthesis of the siderophore aerobactin, encoded within a pathogenicity island. Taken together, this data suggest in the iron-poor environment of the urinary tract, amino acid availability could play a role in the proliferation of this uropathogen, particularly if there is sufficient O 2 to produce aerobactin.
Project description:Transcriptional profiles of uropathogenic Escherichia coli CFT073 exposed to cranberry-derived proanthocyanidins (PACs) were determined. Our results indicate that bacteria grown on media supplemented with PACs were iron-deprived. To our knowledge, this is the first time that PACs have been shown to induce a state of iron-limitation in this bacterium. Cultures of E. coli CFT073 were streaked onto LB agar plates and incubated (37°C, 24 h). A single colony was inoculated into 150 mL of LB broth. Three inoculated flasks contained LB broth alone (controls), and three inoculated flasks were supplemented with cranberry PACs (100 µg/mL). After incubation (37°C, 5 h, 200 rpm to mid-log growth phase), bacteria were harvested for RNA extraction.
Project description:The purpose of this study is to determine whether the presence of pathogenic Escherichia coli in colon is associated with psychiatric disorders.
Project description:Despite the characterization of many aetiologic genetic changes. The specific causative factors in the development of sporadic colorectal cancer remain unclear. This study was performed to detect the possible role of Enteropathogenic Escherichia coli (EPEC) in developing colorectal carcinoma.
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