Project description:Comparative genomic hybridization between Escherichia coli strains to determine core and pan genome content of clinical and environmental isolates Two color experiment, Escherichia coli Sakai (reference), clinical and environmental Escherichia coli strains (testers): At least two replicates including a single dye swap for each reference-tester comparison
Project description:Enterotoxigenic Escherichia coli (ETEC) is a globally prevalent cause of diarrhea. We report the first gene expression analysis of the human host response to experimental challenge with ETEC.
Project description:Comparative genomic hybridization between Escherichia coli strains to determine core and pan genome content of clinical and environmental isolates
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:The experiment contains ChIP-seq data for Enterotoxigenic Escherichia coli strain H10407 transformed with plasmids pAMNF (encoding an N-terminal MarR-3xFLAG fusion) or pAMNM (encoding an N-terminal MarR-8xmyc fusion). The cells was cultured at 37 degrees in LB medium and crosslinked with 1 % (v/v) formaldehyde. After sonication, to break open cells and fragment DNA, immunoprecipitations were done using an anti-FLAG antibody (i.e. the strain encoding the MarR-8xmyc fusion was used as a control). Libraries were prepared using DNA remaining after immunoprecipitation.
Project description:The intention of this study is to analyse the effect of antibiotics on the gene expression of Escherichia coli. Shaking-flask cultivations of Escherichia coli K12GFP-UTL2 were carried out with a medium containing nalidixic acid. Cultures with antibiotic-free medium, which were run in an identical way, served as reference. Samples were taken at different times during the cultivations, the RNA was isolated and hybridised on whole genome yeast microarrays. Keywords: Influence of toxins on gene expression in E. coli
Project description:Background: Based on 32 Escherichia coli and Shigella genome sequences, we have developed an E. coli pan-genome microarray. Publicly available genomes were annotated in a consistent manor to define all currently known genes potentially present in the species. The chip design was evaluated by hybridization of DNA from two sequenced E. coli strains, K-12 MG1655 (a commensal) and O157:H7 EDL933 (an enterotoxigenic E. coli). A dual channel and single channel analysis approach was compared for the comparative genomic hybridization experiments. Moreover, the microarray was used to characterize four unsequenced probiotic E. coli strains, currently marketed for beneficial effects on the human gut flora. Results: Based on the genomes included in this study, we were able to group together 2,041 genes that were present in all 32 genomes. Furthermore, we predict that the size of the E. coli core genome will approach ~1,560 essential genes, considerably less than previous estimates. Although any individual E. coli genome contains between 4,000 and 5,000 genes, we identified more than twice as many (11,872) distinct gene groups in the total gene pool (“pan-genome”) examined for microarray design. Benchmarking of the design based on sequenced control strain samples demonstrated a high sensitivity and relatively low false positive rate. Moreover, the array was highly sufficient to investigate the gene content of apathogenic isolates, despite the strong bias towards pathogenic E. coli strains that have been sequenced so far. Our analysis of four probiotic E. coli strains demonstrate that they share a gene pool very similar to the E. coli K-12 strains but also show significant similarity with enteropathogenic strains. Nonetheless, virulence genes were largely absent. Strain-specific genes found in probiotic E. coli but absent in E. coli K12 were most frequently phage-related genes, transposases and other genes related to mobile DNA, and metabolic enzymes or factors that may offer colonization fitness, which together with their asymptomatic nature may explain their nature. Conclusion: This high-density microarray provides an excellent tool for characterizing either DNA content or gene expression from unknown E. coli strains. Keywords: Comparative genomic hybridizations
Project description:The experiment contains ChIP-seq data for Enterotoxigenic Escherichia coli strain H10407 transformed with plasmid pRGM9818. The strain was grown at 37 degrees in LB medium and crosslinked with 1 % (v/v) formaldehyde. After sonication, to break open cells and fragment DNA, immunoprecipitations were done using antibodies against MarA, MarR or the RNA polymerase sigma 70 subunit. Libraries were prepared using DNA remaining after immunoprecipitation. Note that the MarR immunoprecipitations were not successful but the data served as a useful control for non-specifically immunoprecipitated DNA sequences.
