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: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:In order to understand the impact of genetic variants on transcription and ultimately in changes in observed phenotypes we have measured transcript levels in an Escherichia coli strains collection, for which genetic and phenotypic data has also been measured.
Project description:Escherichia coli release Extracellular Vesicles (EVs) which carry diverse molecular cargo. Pathogenic E.coli EVs contain virulence factors which assist during infection in the host in different mechanisms.The RNA cargo of E.coli EVs has not been assessed in their effect in the host. We used microarray data to asses and compare the global response of bladder cells to EV-RNA from pathogenic E.coli (Uropathogenic UPEC 536) and non-pathogenic E. coli (probiotic Nissle 1917)
Project description:Escherichia coli Nissle 1917 (EcN) is a probiotic used for treatment of intestinal disorders. EcN improves gastrointestinal homeostasis and microbiota balance; however little is known about how this probiotic delivers effector molecules to the host. Outer membrane vesicles (OMVs) are constitutively produced by gram-negative bacteria and have a relevant role in bacteria-host interactions. Here we performed proteomic analysis of EcN OMVs. Using 1D SDSD-PAGE and highly sensitive LC-MS/MS analysis we identified 192 EcN vesicular proteins with high confidence in three independent experiments. Of these proteins, 18 were encoded by strain-linked genes and 57 were common to pathogen-derived OMVs. These proteins may contribute to the ability of this probiotic to colonize the human gut as they fulfil functions related to adhesion to host tissues, immune modulation or bacterial survival in host niches. This study describes the first global OMV proteome of a probiotic strain and provides evidence that probiotic-derived OMVs contain proteins that can target these vesicles to the host and mediate their beneficial effects on intestinal function.
Project description:To investigate the regulatory targets of the RegR virulence regulon of rabbit specific enteropathogenic Escherichia coli strain E22
Project description:we designed a CRISPR-based chromosome-doubling technique to construct an artificial diploid Escherichia coli cell. The stable diploid E. coli was confirmed by quantitative PCR and third-generation genome sequencing.
Project description:Escherichia coli Nissle 1917 (EcN) is an intestinal probiotic that is effective for the treatment of intestinal disorders, such as inflammatory bowel disease and ulcerative colitis. EcN is a representative Gram-negative probiotic in biomedical research and is an intensively studied probiotic. However, to date, its genome-wide metabolic network model has not been developed. Here, we developed a comprehensive and highly curated EcN metabolic model, referred to as iDK1463, based on genome comparison and phenome analysis. The model was improved and validated by comparing the simulation results with experimental results from phenotype microarray tests. iDK1463 comprises 1463 genes, 1313 unique metabolites, and 2984 metabolic reactions. Phenome data of EcN were compared with those of Escherichia coli intestinal commensal K-12 MG1655. iDK1463 was simulated to identify the genetic determinants responsible for the observed phenotypic differences between EcN and K-12. Further, the model was simulated for gene essentiality analysis and utilization of nutrient sources under anaerobic growth conditions. These analyses provided insights into the metabolic mechanisms by which EcN colonizes and persists in the gut. iDK1463 will contribute to the system-level understanding of the functional capacity of gut microbes and their interactions with microbiota and human hosts, as well as the development of live microbial therapeutics.