Global transcriptional response of E. coli to the presence and absence of bile salts
Ontology highlight
ABSTRACT:
ORGANISM(S): Escherichia coli
PROVIDER: GSE20380 | GEO | 2012/07/31
SECONDARY ACCESSION(S): PRJNA125503
REPOSITORIES: GEO
Similar Datasets
Project description:Unlike many other types of diarrheagenic bacteria that act primarily in the small intestine, O157:H7 expresses virulence primarily in the large intestine. In this study, microarray analysis is employed to examine the transcriptional response of O157:H7 to bile treatment, to gain insight into how bile affects virulence and whether bile might be temporally defending the small intestine against virulence by these bacteria. Keywords: Expression profiling of two different growth conditions Two groups of three replicates were used: E.coli O157:H7 grown in Luria broth with or without 0.8% bile salts
2012-07-30 | E-GEOD-20380 | biostudies-arrayexpress
Project description:Enterohemorrhagic Escherichia coli (EHEC), including serotype O157:H7, cause severe food-borne illness. On route to the human colon, they encounter and resist, numerous anti-microbial ingestion stresses. We hypothesize that these stresses cue EHEC to alter virulence properties. This study investigated the impact of bile salts on virulence properties and examined the genetic basis of the phenotypes. Established assays were used to examine adhesion to human epithelial cells, motility, verotoxin (VT) production and antimicrobial resistance with/without bile salt stress. Bacteria treated for 90 minute in DMEM plus 0.15% (w/v) bile salt mix demonstrated significantly enhanced adhesion to epithelial cells and resistance to several antibiotics but did not increase motility or VT production. To determine the genetic basis of these phenotypes a microarray experiment was conducted. EHEC strain 86-24, in mid-log phase of growth, were grown in DMEM pH 7.4 (control), or DMEM plus bile salt mix (0.15% w/v), for 90 minutes, statically at 37˚C, 5% CO2 prior to harvesting RNA for the microarray study. Four biological replicates were produced for each treatment. Microarray and gene expression analysis (semi-quantitative RT-PCR and beta-galactosidase reporter assays) of bile salt-treated EHEC revealed significant up-regulation of genes for lipid A modification, fimbriae, an efflux pump, and a two-component regulatory system relative to the bacteria grown in DMEM alone. This work points to several mechanisms that EHEC employs to resist the stresses of the human small intestine, notably efflux, antimicrobial resistance, and outer membrane alterations. Bile salts enhanced the virulence-related properties of increased adhesion and resistance to antimicrobials but not VT production or motility. This research contributes to our understanding of how EHEC senses and responds to host environmental signals and the mechanisms this pathogen uses to successfully colonize and infect the human host.
2011-09-06 | GSE22060 | GEO
Project description:Enterohemorrhagic Escherichia coli (EHEC), including serotype O157:H7, cause severe food-borne illness. On route to the human colon, they encounter and resist, numerous anti-microbial ingestion stresses. We hypothesize that these stresses cue EHEC to alter virulence properties. This study investigated the impact of bile salts on virulence properties and examined the genetic basis of the phenotypes. Established assays were used to examine adhesion to human epithelial cells, motility, verotoxin (VT) production and antimicrobial resistance with/without bile salt stress. Bacteria treated for 90 minute in DMEM plus 0.15% (w/v) bile salt mix demonstrated significantly enhanced adhesion to epithelial cells and resistance to several antibiotics but did not increase motility or VT production. To determine the genetic basis of these phenotypes a microarray experiment was conducted. EHEC strain 86-24, in mid-log phase of growth, were grown in DMEM pH 7.4 (control), or DMEM plus bile salt mix (0.15% w/v), for 90 minutes, statically at 37˚C, 5% CO2 prior to harvesting RNA for the microarray study. Four biological replicates were produced for each treatment. Microarray and gene expression analysis (semi-quantitative RT-PCR and beta-galactosidase reporter assays) of bile salt-treated EHEC revealed significant up-regulation of genes for lipid A modification, fimbriae, an efflux pump, and a two-component regulatory system relative to the bacteria grown in DMEM alone. This work points to several mechanisms that EHEC employs to resist the stresses of the human small intestine, notably efflux, antimicrobial resistance, and outer membrane alterations. Bile salts enhanced the virulence-related properties of increased adhesion and resistance to antimicrobials but not VT production or motility. This research contributes to our understanding of how EHEC senses and responds to host environmental signals and the mechanisms this pathogen uses to successfully colonize and infect the human host. Bacteria were grown in LB broth overnight with shaking, then subcultured into DMEM and grown statically at 37˚C, 5%CO2 to mid-log phase. Bacteria were then subjected to one of two 90 minute treatments: 1) Control: DMEM pH 7.4, or 2) Bile Salt Stress: DMEM pH 7.4 plus 0.15%, grown statically at 37˚C, 5%CO2.
2011-09-05 | E-GEOD-22060 | biostudies-arrayexpress
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:Pathogenic biofilms have been associated with persistent infections due to high resistance to antimicrobial agents while commensal biofilms often fortify host immune system. Hence, controlling biofilm formation of both pathogenic bacteria and commensal bacteria is important in bacteria-related diseases. We investigated the effect of plant flavonoids on biofilm formation of both enterohemorrhagic Escherichia coli O157:H7 and three commensal E. coli K-12 strains. Phloretin abundant in apples markedly reduced E. coli O157:H7 biofilm formation without affecting the growth of planktonic cells while phloretin did not harm commensal E. coli K-12 biofilms. Also, phloretin reduced E. coli O157:H7 attachment to human colon epithelial cells. Global transcriptome analyses revealed that phloretin repressed toxin genes (hlyE and stx2), autoinducer-2 importer genes (lsrACDBF), a curli gene (csgA), and a dozens of prophage genes in E. coli O157:H7 cells. Electron microscopy confirmed that phroretin reduced the curli production in E. coli O157:H7. In addition, phloretin suppressed TNF-α-induced inflammatory response in vitro using human colonic epithelial cells. Moreover, in the trinitrobenzene sulfonic acid (TNBS)-induced rat colitis model, phloretin significantly ameliorated colon inflammation and body weight loss. Taken together, our results suggest that phloretin may act as an inhibitor of E. coli O157:H7 biofilm formation as well as anti-inflammatory agent on inflammatory bowel diseases while leaving beneficial commensal E. coli biofilm intact.
2011-11-22 | GSE28144 | GEO
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:Secreted proteins constitute a major part of virulence factors that are responsible for pathogenesis caused by gram negative bacteria. Enterohemorrhagic Escherichia coli (E. coli), EHEC O157:H7 is the major pathogen often causing outbreaks. There is growing evidence that non-O157:H7 E. coli strains may also be involved in the recent outbreaks. However, there is no systematic study describing differential secreted proteins from non-O157:H7 E. coli strains. Here, we have applied isobaric tag-based TMT labeling combined with high-resolution Fourier transform mass spectrometry to study the differential secretome analysis of major non-O157:H7 E. coli strains, O103, O111, O121, O145, O26 and O45, which is known as diarrhea inducing non-O175:H7 ATCC “big six” serogroup E. coli strains. We identified 1,240 proteins quantitatively identified, 565 proteins were found to be secreted as predicted by PSORTb and SecretomeP. We identified 310 proteins containing signal peptide and 255 proteins as secreted. We identified 20 strain specific proteins with in big-six group and was confirmed by proteogenomics approach. Further we enriched and have shown relative expression of type III secretion system. To our knowledge, this study is the first comparative proteomic study on secretome of E. coli big six serogroup and the several of these strain specific secreted proteins can be further studied to develop potential markers for identification and strain level differentiation. Moreover, the results of this study can be utilized in several applications, including food safety, diagnostics of E. coli outbreaks, and biodefense.
2018-07-05 | PXD004372 | Pride
Project description:Bile Salts Influence Virulence Properties of E. coli O157:H7
| PRJNA128967 | ENA
Project description:The effect of pooled immunoglobulins (IgG) on E. coli O157:H7 colonization and the course of disease in an EHEC mouse model was investigated showing an improved survival and decreased intestinal and renal pathology. Treatment was given after inoculation thereby corresponding to the clinical setting. In vitro studies identified E. coli serine protease EspP as the E. coli O157:H7 protein that IgG bound to, via the Fc fragment, in both murine and human IgG preparations, and blocked its enzymatic activity. EspP is a virulence factor previously shown to promote colonic cell injury and the uptake of Shiga toxin by intestinal cells. The results suggest that IgG in commercial preparations binds to EspP protecting the host from E. coli O157:H7 infection and could potentially be beneficial in patients.
2022-02-08 | PXD029563 | Pride
Project description:The human intestinal microbiota associated with rats produces in vivo a soluble(s) factor(s) that down-regulates the expression of genes encoding for the Shiga toxin II in E. coli O157:H7. The Shiga toxin II is one of the major virulence factors of E. coli enterohemorragic leading to the deadly hemolitic and uremic syndrome. Investigation of the effect of the human intestinal microbiota on the whole transcriptome of EHEC O157:H7 is of major importance to increase our understanding of the pathogen transcriptomic adaptation in response to the human microbiota. We analysed by microarray hybridization the gene expression pattern of EHEC O157:H7 grown in the caecal content of germ-free rats or rats associated with the human microbiota of a healthy human subject. By doing so, we increased our understanding of the regulatory activities of the human gut microbiota on E. coli O157:H7
2013-09-10 | GSE37095 | GEO