Escherichia coli K-12
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PROVIDER: PRJNA110989 | ENA |
REPOSITORIES: ENA
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Project description:RpoS, an alternative sigma factor, is critical for stress response in Escherichia coli. The RpoS regulon expression has been well characterized in rich media that support fast growth and high growth yields. In contrast, though RpoS levels are high in minimal media, how RpoS functions under such conditions has not been clearly resolved. In this study, we compared the global transcriptional profiles of wild type and an rpoS mutant of E. coli grown in glucose minimal media using microarray analyses. The expression of over 200 genes was altered by loss of RpoS in exponential and stationary phases, with only 48 genes common to both conditions. The nature of the RpoS-controlled regulon in minimal media was substantially different from that expressed in rich media. Specifically, the expression of many genes encoding regulatory factors (e.g., hfq, csrA and rpoE) and genes in metabolic pathways (e.g., lysA, lysC and hisD) were regulated by RpoS in minimal media. In early exponential phase, protein levels of RpoS in minimal media were much higher than that in LB media, which may at least partly account for the observed difference in the expression of RpoS-controlled genes. Expression of genes required for flagellar function and chemotaxis was elevated in the rpoS mutant. Western blot analyses show that the flagella sigma factor FliA was expressed much higher in rpoS mutants than in WT in all phase of growth. Consistent with this, the motility of rpoS mutants was enhanced relative to WT. In conclusion, RpoS and its controlled regulators form a complex regulatory network that mediates the expression of a large regulon in minimal media.
2008-10-10 | GSE12797 | GEO
Project description:RpoS, an alternative sigma factor, is critical for stress response in Escherichia coli. The RpoS regulon expression has been well characterized in rich media that support fast growth and high growth yields. In contrast, though RpoS levels are high in minimal media, how RpoS functions under such conditions has not been clearly resolved. In this study, we compared the global transcriptional profiles of wild type and an rpoS mutant of E. coli grown in glucose minimal media using microarray analyses. The expression of over 200 genes was altered by loss of RpoS in exponential and stationary phases, with only 48 genes common to both conditions. The nature of the RpoS-controlled regulon in minimal media was substantially different from that expressed in rich media. Specifically, the expression of many genes encoding regulatory factors (e.g., hfq, csrA and rpoE) and genes in metabolic pathways (e.g., lysA, lysC and hisD) were regulated by RpoS in minimal media. In early exponential phase, protein levels of RpoS in minimal media were much higher than that in LB media, which may at least partly account for the observed difference in the expression of RpoS-controlled genes. Expression of genes required for flagellar function and chemotaxis was elevated in the rpoS mutant. Western blot analyses show that the flagella sigma factor FliA was expressed much higher in rpoS mutants than in WT in all phase of growth. Consistent with this, the motility of rpoS mutants was enhanced relative to WT. In conclusion, RpoS and its controlled regulators form a complex regulatory network that mediates the expression of a large regulon in minimal media. Experiment Overall Design: A precise rpoS deletion mutant of MG1655 was constructed using the red recombinase method. Wild type and rpoS mutants were inoculated in triplicate into M63 glucose (0.2%) minimal media at a starting OD of 0.0001 and grown aerobically at 37oC. Cultures were harvested at OD600= 0.3 in exponential phase and at OD600= 1.5 in stationary phase. For RNA extraction, cultures were mixed directly with a boiling lysis buffer containing SDS and EDTA followed by acidic hot phenol (65C) to minimize RNA degradation. RNA samples were hybridized to Affymetrix E. coli Antisense Genome Array according to Affymetrix's standard protocols.
2008-10-26 | E-GEOD-12797 | biostudies-arrayexpress
Project description:To determine sites where RpoS binds (and hence likely plays a direct role in transcription), we used ChIP-seq to map the association of RpoS across the Escherichia coli chromosome during stationary phase growth in minimal medium. To facilitate ChIP, RpoS was C-terminally SPA-tagged at its native locus.
2016-12-23 | E-MTAB-5339 | biostudies-arrayexpress
Project description:In 2011, in Germany, Escherichia coli O104:H4 caused the enterohemorrhagic E. coli (EHEC) outbreak with the highest incidence rate of hemolytic uremic syndrome. This pathogen carries an exceptionally potent combination of EHEC- and enteroaggregative E. coli (EAEC)-specific virulence factors. Here, we identified an E. coli O104:H4 isolate that carried a single nucleotide polymorphism (SNP) in the start codon (ATG>ATA) of rpoS, encoding the alternative sigma factor S. The rpoS ATG>ATA SNP was associated with enhanced EAEC-specific virulence gene expression. Deletion of rpoS in E. coli O104:H4 Dstx2 and typical EAEC resulted in a similar effect. Both rpoS ATG>ATA and DrpoS strains exhibited stronger virulence-related phenotypes in comparison to wild type. Using promoter-reporter gene fusions, we demonstrated that wild-type RpoS repressed aggR, encoding the main regulator of EAEC virulence. In summary, our work demonstrates that RpoS acts as a global repressor of E. coli O104:H4 virulence, primarily through an AggR-dependent mechanism.
2024-04-04 | GSE243699 | GEO
Project description:RpoS, an alternative sigma factor, is critical for stress response in Escherichia coli.RpoS also acts as a global regulator for stress control of gene expression, and actually dose so in log stage and stationary stage. To further understand the effect of environmental stresses on in ethanologenic strains, DNA microarrys was used to analyze the expression profiles of E. coli and its rpoS mutant strain.
2010-07-20 | GSE17526 | GEO
Project description:Escherichia coli (E. coli) amine oxidase (ECAO) encoded by tynA gene has been one of the model enzymes to study the mechanism of oxidative deamination of amines to the corresponding aldehydes by amine oxidases. The biological roles of ECAO have been less addressed. Therefore we have constructed a gene deletion Escherichia coli K-12 strain, E. coli tynA-, and used the microarray technique to address its function by comparing the total RNA gene expression to the one of the wt. Our results suggest that tynA is a reserve gene for stringent environmental conditions and its gene product ECAO a growth advantage compared to other bacteria due to H2O2 production.
2015-09-30 | GSE65385 | GEO
Project description:The faecal indicator bacterium Escherichia coli K12 was used to study the effects of the global regulators RpoS and cAMP at the transcription level using microarray technology during short-term (physiological) adaptation to slow growth under limited nutrient supply. Effects due to the absence of one global regulator were assessed by comparing the mRNA levels isolated from rpoS or cya mutants under glucose-limited continuous culture at a dilution rate of 0.3 h-1 for the rpoS mutant or 0.16 h-1 for the cya mutant with those from wt E. coli grown under the same conditions.
2010-12-16 | GSE25982 | GEO
Project description:Bacteria generally possess multiple σ factors that, based on structural and functional similarity, divide into two families: σD and σN. Among the seven σ factors in Escherichia coli, six belongs to the σD family. Each σ factor recognizes a group of promoters, providing effective control of differential gene expression. Many studies have shown that σ factors of the σD family compete with each other for function. In contrast, the competition between σN and σD families has yet to be fully explored. Here we report a global antagonistic effect on gene expression between two alternative σ factors, σN (RpoN) and σS (RpoS), a σD family protein. Mutations in rpoS and rpoN inversely affected a number of cellular traits, such as expression of flagellar genes, σN-controlled growth on poor nitrogen sources, and σS-directed expression of acid phosphatase AppA. Transcriptome analysis reveals that 40% of genes in the RpoN regulon were under reciprocal RpoS control. Furthermore, loss of RpoN led to increased levels of RpoS, while RpoN levels were unaffected by rpoS mutations. Expression of the flagellar σF factor (FliA), another σD family protein, was controlled positively by RpoN but negatively by RpoS. These findings unveil a complex regulatory interaction among σN, σS and σF, and underscore the need to employ systems biology approaches to assess the effect of such interaction of σ factors on cellular functions, including motility, nutrient utilization, and stress response. Precise deletion mutants of rpoS or rpoN of MG1655 were constructed and employed in this study. Cultures were inoculated in triplicate in M9 minimal media (0.2% glucose) at a starting OD of 0.0001 and grown aerobically at 37C. Cultures were harvested at OD600 = 0.3 in exponential phase. For RNA extraction, cultures were mixed directly with a boiling lysis buffer containing SDS and EDTA followed by acidic hot phenol to minimize RNA degradation. RNA samples were hybridized to Affymetrix E. coli Genome 2.0 Array according to Affymetrix's standard protocols.
2010-12-04 | E-GEOD-20095 | biostudies-arrayexpress
Project description:The physiological role of the various nucleoid-associated proteins in bacteria and HU in particular has been addressed in a number of studies but remains so far not fully understood. In this work, a genome-wide microarray hybridization approach, combined with in vivo genetic experimentation, has been performed in order to compare and evaluate the effect of HUalpha, HUbeta and HUalphabeta on the transcription of the Escherichia coli K12 genes as a function of growth phase. The histone-like protein HU is present in the E. coli cell under three dimeric forms (HUalphabeta, HUalpha2 and HUbeta2) in a ratio that varies with growth phase. The experimental protocol is designed to handle strain genotype and growth phase as independent variables. Experiment Overall Design: We used microarrays to investigate global bacterial gene expression in five genotypes of E. coli C600: WT (JO2057), hupA (JO2081), hupB (JO2083), hupAB (JO3020) and rpoS (MW30) at three growth growth phases: exponential, transition and stationary and in three growth media: LB, M9 minimal Glucose and M9 minimal Glycerol. The most relevant experiments were carried out in duplicate: the wild type (JO2057) and the hupAB (JO3020) strains were tested in the exponential and stationary phase, in LB. Wild type and hupAB strains were also tested in single experiments at the transition phase in LB. The single hupA (JO2081) and single hupB (JO2083) mutants were tested at the three growth phases in LB. Wild type and hupAB strains were compared in single experiments both in M9 Minimal Glucose and M9 Minimal Glycerol at the exponential and stationary phase. The last chips were used to test respectively the rpoS mutant at the at the exponential and stationary phase in LB.
2009-01-14 | E-GEOD-11183 | biostudies-arrayexpress
Project description:Investigation of whole genome gene expression level in E. coli rpoS knock-out strain grown up to stationary phase in M9 minimal media supplemented with 0.2% glucose
2014-02-05 | GSE46543 | GEO