Transcriptional profiling of 2 outbreak strains of E. coli O157:H7 following exposure to epithelial cells
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ABSTRACT:
ORGANISM(S): Escherichia coli
PROVIDER: GSE17389 | GEO | 2009/09/17
SECONDARY ACCESSION(S): PRJNA118825
REPOSITORIES: GEO
Similar Datasets
Project description:Two outbreak strains of E. coli O157:H7 differ phylogenetically, in gene content, and in epidemiological characteristics. The working hypothesis in this experiment was that these strains will also differ in the transcription of shared virulence genes. Indeed, following a 30 minute exposure to epithelial cells, strain TW14359 overexpressed major and ancillary virulence genes, relative to strain Sakai. E. coli O157:H7 strains were physiologically normalized by growth to stationary phase, twice, in MOPS minimal media. Cultures were then transferred to DMEM media for adaptation. After 3 h of growth in DMEM, O157:H7 cultures were used to infect monolayers of MAC-T epithelial cells. 30 min following incubation, aliquots of suspended, non-adherent bacteria were used for RNA extraction. Five biological replications of the experiment were performed with each strain and, together with dye-swaps, 10 array hybridizations were carried out. Array data were fitted to a mixed model ANOVA using the following linear model: array+dye+sample (biological replicate)+strain+error.
2010-05-05 | E-GEOD-17389 | biostudies-arrayexpress
Project description:Minimal processing using chlorinated water washes is a common practice in the fresh produce industry to reduce the microbial load and bacterial pathogens attached on produce surfaces. To evaluate if E. coli O157:H7 strains with different phyllogenetic backgrounds are equally sensitive or display variable resistance to chlorine treatment, we studied the expression profile of Sakai and one 2006 spinach outbreak strain (TW 14359) in response to chlorine and hydrogen peroxide treatment.
2009-04-04 | GSE15533 | GEO
Project description:Minimal processing using chlorinated water washes is a common practice in the fresh produce industry to reduce the microbial load and bacterial pathogens attached on produce surfaces. To evaluate if E. coli O157:H7 strains with different phyllogenetic backgrounds are equally sensitive or display variable resistance to chlorine treatment, we studied the expression profile of Sakai and one 2006 spinach outbreak strain (TW 14359) in response to chlorine and hydrogen peroxide treatment. Experiment Overall Design: 2 E. coli O157 strains are incubated with or without chlorine or H2O2 for 30 min for RNA extraction and hybridization on Affymetrix microarrays. We sought to compare the expression profile between the 2 strains with or without oxidative stress.
2009-04-11 | E-GEOD-15533 | biostudies-arrayexpress
Project description:Integrating laterally acquired virulence genes into the backbone regulatory network is important for the pathogenesis of Escherichia coli O157:H7, which has captured many virulence genes through horizontal transfer during evolution. GadE is an essential transcriptional activator of glutamate decarboxylase (GAD) system, the most efficient acid resistance mechanism in E. coli. The full contribution of GadE to the acid resistance and virulence of pathogenic E. coli O157:H7 remains largely unknown. We inactivated gadE in E. coli O157:H7 Sakai and compared global transcription profiles with that of wild type in exponential and stationary phases of growth using microarrays containing 6088 ORFs from three E. coli genomes. gadE inactivation significantly altered the expression of 60 genes independent of growth phase and 122 genes in a growth phase-dependent manner. Inactivation of gadE markedly down-regulated the expression of gadA, gadB, gadC and many acid fitness island genes in a growth phase-dependent manner. Nineteen genes encoded on the locus of enterocyte effacement (LEE), including ler, showed a significant increase in expression upon gadE inactivation. Altogether, our data indicate that GadE is critical for acid resistance of E. coli O157:H7 and plays an important role in virulence by down-regulating expression of LEE. The results are based on O157:H7 Sakai wild type and gadE mutant exponential and stationary phase cultures grown in MOPS minimal medium. Differences in transcript levels were determined using a mixed model ANOVA in R/MAANOVA which tested for significant differences due to growth phase (exponential or stationary), strain (wild type or mutant) and the interaction of these two factors using the following linear model: array+dye+sample (biological replicate)+ phase+strain+phase*strain. We incorporated the dye-swaps among the biological replicates.
2010-05-18 | E-GEOD-13132 | biostudies-arrayexpress
Project description:Six isolates of PT21/28 and six of PT32 were analysed by CGH using UBECarray3 microarrays (containing probes for E. coli K-12 str. MG1655 and O157:H7 str. EDL933 and Sakai) to define genotypic differences between phage types. gDNA from E.coli O157 str. Sakai was hybridised to all arrays to provide a universal control channel on all arrays.
2012-04-21 | GSE28838 | GEO
Project description:We compared the transcriptional profiles of 12 E. coli O157:H7 isolates grown to stationary phase in LB broth. These isolates possess the same two enzyme PFGE profile and are related temporally or geographically to the above outbreak. These E. coli O157:H7 isolates included three clinical isolates, five isolates from separate bags of spinach, and single isolates from pasture soil, river water, cow feces, and a feral pig.
2011-11-01 | GSE33131 | GEO
Project description:Comparative analysis of EHEC O157:H7 Sakai vs. TW14359 secreted and cytosolic protein using iTRAQ and mass spectrometry on an LTQ Orbitrap. Samples were fractionated through strong cation exchange and HPLC before analsyis. For TW14359 sepD secretome analysis, strains were similarly prepared and analyzed. All samples were searched against a TW14359 specific protein database (Uniprot) coupled with randomized protein sequences.
2013-09-05 | PXD000023 | Pride
Project description:Integrating laterally acquired virulence genes into the backbone regulatory network is important for the pathogenesis of Escherichia coli O157:H7, which has captured many virulence genes through horizontal transfer during evolution. GadE is an essential transcriptional activator of glutamate decarboxylase (GAD) system, the most efficient acid resistance mechanism in E. coli. The full contribution of GadE to the acid resistance and virulence of pathogenic E. coli O157:H7 remains largely unknown. We inactivated gadE in E. coli O157:H7 Sakai and compared global transcription profiles with that of wild type in exponential and stationary phases of growth using microarrays containing 6088 ORFs from three E. coli genomes. gadE inactivation significantly altered the expression of 60 genes independent of growth phase and 122 genes in a growth phase-dependent manner. Inactivation of gadE markedly down-regulated the expression of gadA, gadB, gadC and many acid fitness island genes in a growth phase-dependent manner. Nineteen genes encoded on the locus of enterocyte effacement (LEE), including ler, showed a significant increase in expression upon gadE inactivation. Altogether, our data indicate that GadE is critical for acid resistance of E. coli O157:H7 and plays an important role in virulence by down-regulating expression of LEE.
2008-10-11 | GSE13132 | GEO
Project description:French outbreak of STEC O157:H7
| PRJEB52802 | ENA
Project description:Escherichia coli O157:H7 is a food-borne pathogen that causes bloody diarrhea and hemolytic uremic syndrome. Hfq is an sRNA chaperone protein that is involved in post-transcriptional regulation of virulence genes in pathogenic bacteria. In EHEC strain EDL933, Hfq acts a negative regulator of the locus of enterocyte effacement (LEE) that encodes most of the proteins involved in type three secretion and attaching and effacing lesions. We deleted hfq in E. coli O157:H7 strain 86-24 and compared global transcription profiles of the hfq mutant to the wild type strain in exponential growth phase. Deletion of hfq affected transcription of genes common to nonpathogenic and pathogenic strains of E. coli as well as pathogen-specific genes. Downregulated genes in the hfq mutant included ler as well as genes encoded in LEE2-5 that encode for type three secretion and AE lesion formation. Decreased expression of the LEE genes in the hfq mutant occurred at mid-, late, and stationary growth phases in both LB and DMEM media as detected by qRT-PCR. We also confirmed decreased regulation of the LEE genes by examining secreted proteins and AE lesion formation by the hfq mutant and WT strains. Deletion of hfq also caused decreased expression of the two-component system qseBC involved in inter-kingdom signaling and virulence gene regulation in EHEC as well as an increase in stx2AB expression that encodes for the deadly Shiga toxin. Altogether, these data indicate that Hfq plays a different regulatory role in EHEC 86-24 from what has been reported for EHEC strain EDL933 and that the role of Hfq in EHEC virulence regulation extends beyond the LEE.
2012-01-06 | GSE30893 | GEO