Effects of sidA and AHL on EHEC virulence
Ontology highlight
ABSTRACT:
ORGANISM(S): Escherichia coli
PROVIDER: GSE13562 | GEO | 2010/04/09
SECONDARY ACCESSION(S): PRJNA110751
REPOSITORIES: GEO
Similar Datasets
Project description:A study on the effects of an sdiA mutant and the AHL molecule on the virulence of EHEC Comparison of wild type E. coli 8624 with and without AHL to and E. coli 8624 sdiA mutant with and without AHL to determine the effects of each factor on gene expression
2010-04-09 | E-GEOD-13562 | biostudies-arrayexpress
Project description:EHEC is a food-borne pathogen that colonizes human GI tract and leads to infection. To understand the process of colonization and to decipher if any factors secreted by intestinal epithelial cells help EHEC during the infection process, we studied expression of EHEC virulence gene expression when exposed to intestinal epithelial cell conditioned medium. In our study, we observed that exposure to epithelial cell conditioned medium for 1 h and 3 h increases expression of 32 out of 41 EHEC LEE virulence genes. In addition, expression of the shiga toxin 1 (Stx1) gene is up-regulated at 1 h of exposure. Also, 17 genes encoded by prophage 933W, including those for Stx2, are also upregulated at both time-points. The increase in 933W prophage expression is mirrored by a 2.7-fold increase in intracellular Stx2 phage titers. Consistent with the increase in virulence gene expression, we observed a 5-fold increase in EHEC attachment to epithelial cells when exposed to conditioned medium, suggesting that EHEC utilizes host cell molecules to increase virulence and infectivity. The molecule(s) responsible for increased EHEC virulence is heat-sensitive as heating the conditioned medium to 95oC abolishes the increase in attachment to epithelial cells. A similar decrease was observed when the conditioned medium was treated with proteinase-K to degrade the proteins. The secreted molecule(s) was found to be larger than 3 kDa and strongly suggests that the HCT-8 secreted molecule that increases EHEC virulence and colonization is a protein-based molecule. Affymetrix E. coli Genome 2.0 Arrays were used to determine the changes in EHEC virulence gene expression on exposure to intestinal epithelial cell-secreted factors (through growth in conditioned medium).
2012-10-04 | GSE22285 | GEO
Project description:EHEC is a food-borne pathogen that colonizes human GI tract and leads to infection. To understand the process of colonization and to decipher if any factors secreted by intestinal epithelial cells help EHEC during the infection process, we studied expression of EHEC virulence gene expression when exposed to intestinal epithelial cell conditioned medium. In our study, we observed that exposure to epithelial cell conditioned medium for 1 h and 3 h increases expression of 32 out of 41 EHEC LEE virulence genes. In addition, expression of the shiga toxin 1 (Stx1) gene is up-regulated at 1 h of exposure. Also, 17 genes encoded by prophage 933W, including those for Stx2, are also upregulated at both time-points. The increase in 933W prophage expression is mirrored by a 2.7-fold increase in intracellular Stx2 phage titers. Consistent with the increase in virulence gene expression, we observed a 5-fold increase in EHEC attachment to epithelial cells when exposed to conditioned medium, suggesting that EHEC utilizes host cell molecules to increase virulence and infectivity. The molecule(s) responsible for increased EHEC virulence is heat-sensitive as heating the conditioned medium to 95oC abolishes the increase in attachment to epithelial cells. A similar decrease was observed when the conditioned medium was treated with proteinase-K to degrade the proteins. The secreted molecule(s) was found to be larger than 3 kDa and strongly suggests that the HCT-8 secreted molecule that increases EHEC virulence and colonization is a protein-based molecule. Affymetrix E. coli Genome 2.0 Arrays were used to determine the changes in EHEC virulence gene expression on exposure to intestinal epithelial cell-secreted factors (through growth in conditioned medium). Overnight cultures of EHEC were diluted in LB medium to a turbidity of 0.1 at 600 nm. The cells were allowed to grow to a turbidity of 1.0 at 600 nm at 37°C and the EHEC cells were then resuspended in either fresh or conditioned medium. The cultures were then allowed to grow for 1 h or 3 h before cell pellets were collected by centrifugation and stored at -80°C. Total RNA was isolated from the cell pellets (173) and RNA quality was assessed using gel electrophoresis. Escherichia coli Genome 2.0 arrays (Affymetrix, Santa Clara, CA, USA) containing 10,208 probe sets for all 20,366 genes present in four strains of E. coli, including EHEC, were used to profile changes in gene expression using RNA samples for each treatment.
2012-10-04 | E-GEOD-22285 | biostudies-arrayexpress
Project description:The transcriptome of EHEC grown in vitro with or without Symbioflor® was analyzed using RNA-seq. The analysis revealed downregulation of several virulence-associated genes in the presence of Symbioflor®, including virulence key genes (e.g., LEE, flagellum, quorum-sensing).
2016-08-24 | GSE85950 | GEO
Project description:The transcriptome of EHEC grown in vitro with or without Symbioflor® was analyzed using RNA-seq. The analysis revealed downregulation of several virulence-associated genes in the presence of Symbioflor®, including virulence key genes (e.g., LEE, flagellum, quorum-sensing). EHEC were grown on LB medium, either with or without Symbioflor added.
2016-08-24 | E-GEOD-85950 | biostudies-arrayexpress
Project description:Enterohemorrhagic E. coli (EHEC) colonizes the large intestine and causes attaching and effacing lesions (AE). Most of the genes involved in the formation of AE lesions are encoded within a chromosomal pathogenicity island termed the Locus of Enterocyte Effacement (LEE). The LysR-like transcriptional factor QseA regulates the LEE by binding directly to the regulatory region of ler. Here, we performed transcriptome analyses comparing WT EHEC and the isogenic qseA mutant in order to elucidate the extent of QseA’s role in gene regulation in EHEC. The following results compare genes that were up-regulated and down-regulated ! 2-fold in the qseA mutant strain compared to the WT strain. At mid-exponential growth, 222 genes were up-regulated and 1874 were downregulated. At late-exponential growth, a total of 55 genes were up-regulated and 605 genes were down-regulated. During mid-exponential growth, QseA represses its own transcription, whereas during late-logarithmic growth, QseA activates expression of the LEE genes as well as non-LEE encoded effector proteins. During both growth phases, several genes carried in O-islands, were activated by QseA, whereas genes involved in cell metabolism were repressed. We also performed electrophoretic mobility shift assays, competition experiments, and DNAseI footprints, and the results suggested that QseA directly binds both the ler proximal and distal promoters, its own promoter, as well as promoters of genes encoded in EHEC-specific O-islands. Additionally, we mapped the transcriptional start site of qseA, leading to the identification of two promoter sequences. Taken together, these results indicate that QseA acts as a global regulator in EHEC, coordinating expression of virulence genes.
2010-09-07 | GSE18118 | GEO
Project description:Enterohemorrhagic E. coli (EHEC) colonizes the large intestine and causes attaching and effacing lesions (AE). Most of the genes involved in the formation of AE lesions are encoded within a chromosomal pathogenicity island termed the Locus of Enterocyte Effacement (LEE). The LysR-like transcriptional factor QseA regulates the LEE by binding directly to the regulatory region of ler. Here, we performed transcriptome analyses comparing WT EHEC and the isogenic qseA mutant in order to elucidate the extent of QseA’s role in gene regulation in EHEC. The following results compare genes that were up-regulated and down-regulated ! 2-fold in the qseA mutant strain compared to the WT strain. At mid-exponential growth, 222 genes were up-regulated and 1874 were downregulated. At late-exponential growth, a total of 55 genes were up-regulated and 605 genes were down-regulated. During mid-exponential growth, QseA represses its own transcription, whereas during late-logarithmic growth, QseA activates expression of the LEE genes as well as non-LEE encoded effector proteins. During both growth phases, several genes carried in O-islands, were activated by QseA, whereas genes involved in cell metabolism were repressed. We also performed electrophoretic mobility shift assays, competition experiments, and DNAseI footprints, and the results suggested that QseA directly binds both the ler proximal and distal promoters, its own promoter, as well as promoters of genes encoded in EHEC-specific O-islands. Additionally, we mapped the transcriptional start site of qseA, leading to the identification of two promoter sequences. Taken together, these results indicate that QseA acts as a global regulator in EHEC, coordinating expression of virulence genes. Design of the study was to make the knockout of the qseA gene and compare the transcriptional response to that and the wild type.
2010-09-07 | E-GEOD-18118 | biostudies-arrayexpress
Project description:Quorum sensing is a cell to cell communication process that involves chemical signaling. Yersinia pestis, the agent of plague, has two functional AHL quorum sensing systems Ysp and Ype. For several reasons, it was not clear what effect AHL pathways have on virulence gene expression and survival in the two different hosts, flea and human. To investigate to what effect AHL quorum sensing has on gene expression, we conducted microarray studies comparing Yersinia pestis CO92 (∆pgm) to a double AHL mutant strain (∆pgm ΔypeIR ΔyspIR) at 37°C.
2016-01-01 | GSE30331 | GEO
Project description:Quorum sensing is a cell to cell communication process that involves chemical signaling. Yersinia pestis, the agent of plague, has two functional AHL quorum sensing systems Ysp and Ype. For several reasons, it was not clear what effect AHL pathways have on virulence gene expression and survival in the two different hosts, flea and human. To investigate to what effect AHL quorum sensing has on gene expression, we conducted microarray studies comparing Yersinia pestis CO92 (∆pgm) to a double AHL mutant strain (∆pgm ΔypeIR) at 30°C.
2016-01-01 | GSE30332 | GEO
Project description:Quorum sensing is a cell to cell communication process that involves chemical signaling. Yersinia pestis, the agent of plague, has two functional AHL quorum sensing systems Ysp and Ype. For several reasons, it was not clear what effect AHL pathways have on virulence gene expression and survival in the two different hosts, flea and human. To investigate to what effect Ysp AHL quorum sensing has on gene expression, we conducted microarray studies comparing Yersinia pestis CO92 (∆pgm) to a single AHL mutant strain (∆pgm ΔyspI) at 30°C.
2016-01-01 | GSE30329 | GEO