Comparative genomic hybridization of environmental Escherichia coli isolates indicates highly conserved ecophysiology
Ontology highlight
ABSTRACT:
ORGANISM(S): Escherichia coli K-12 Escherichia coli
PROVIDER: GSE6407 | GEO | 2006/12/05
SECONDARY ACCESSION(S): PRJNA99543
REPOSITORIES: GEO
Similar Datasets
Project description:Escherichia coli, the common inhabitant of the mammalian intestine, exhibits considerable intraspecies genomic variation, which has been suggested to reflect adaptation to different ecological niches. Also, regulatory trade-offs, e.g., between catabolic versatility and stress protection, are thought to result in significant physiological differences between strains. For these reasons, the relevance of experimental observations made for âdomesticatedâ E. coli strains with regard to the behaviour of this species in its natural environments is often questioned and frequently doubts are raised on the status of E. coli as a defined species. We therefore investigated the variability of important eco-physiological functions such as carbon substrate uptake and breakdown capabilities as well as stress defence mechanisms in the genomes of commensal and pathogenic E. coli strains. Furthermore, eco-physiological properties of environmental strains were compared to standard laboratory strain K-12 MG1655. Catabolic, stress protection, and carbon- and energy source transport operons showed a very low intraspecies variability in 57 commensal and pathogenic E. coli. Environmental isolates adapted to glucose-limited growth in a similar way as E. coli MG1655, namely by increasing their catabolic flexibility and by inducing high affinity substrate uptake systems. Our results indicate that the major eco-physiological properties are highly conserved in the natural population of E. coli. This questions the proposed dominant role of horizontal gene transfer for niche adaptation. Keywords: comparative genomic hybridisation Standard approach for comparative genomic hybrisisation, 5 environmental strains were analysed on commercial E. coli MG1655 arrays (MWG), for each strains, biological replicates were done (separate LB cultures)
2006-12-04 | E-GEOD-6407 | biostudies-arrayexpress
Project description:Escherichia coli, the common inhabitant of the mammalian intestine, exhibits considerable intraspecies genomic variation, which has been suggested to reflect adaptation to different ecological niches. Also, regulatory trade-offs, e.g., between catabolic versatility and stress protection, are thought to result in significant physiological differences between strains. For these reasons, the relevance of experimental observations made for “domesticated” E. coli strains with regard to the behaviour of this species in its natural environments is often questioned and frequently doubts are raised on the status of E. coli as a defined species. We therefore investigated the variability of important eco-physiological functions such as carbon substrate uptake and breakdown capabilities as well as stress defence mechanisms in the genomes of commensal and pathogenic E. coli strains. Furthermore, eco-physiological properties of environmental strains were compared to standard laboratory strain K-12 MG1655. Catabolic, stress protection, and carbon- and energy source transport operons showed a very low intraspecies variability in 57 commensal and pathogenic E. coli. Environmental isolates adapted to glucose-limited growth in a similar way as E. coli MG1655, namely by increasing their catabolic flexibility and by inducing high affinity substrate uptake systems. Our results indicate that the major eco-physiological properties are highly conserved in the natural population of E. coli. This questions the proposed dominant role of horizontal gene transfer for niche adaptation. Keywords: CGH, E. coli, gDNA, environmental strains, eco-physiology
2007-04-01 | GSE6486 | GEO
Project description:Transcriptome profiling of E. coli MG1655, E. coli EDL933, E. coli ECOR26, and E. coli Nissle 1917 grown on mouse cecal mucus as carbon source The carbon sources that support growth of pathogenic E. coli O157:H7 in the mammalian intestine have not previously been investigated. In vivo, pathogenic E. coli EDL933 primarily grows as dispersed single cells within the mucus layer that overlies the mouse cecal epithelium. We therefore compared the pathogen and commensal E. coli MG1655 for their mode of metabolism in vitro on a mixture of the sugars known to be present in cecal mucus and found that the two strains used the thirteen sugars in a similar order and co-metabolized as many as nine sugars at a time. We conducted a systematic mutational analysis of E. coli EDL933 and E. coli MG1655 with lesions in the pathways used for catabolism of thirteen mucus-derived sugars and five other compounds for which the corresponding gene system was induced in the transcriptome of cells grown on cecal mucus. Each of 18 catabolic mutants in both genetic backgrounds was fed to streptomycin-treated mice together with the respective wildtype parent strain and their colonization was monitored in fecal plate counts. None of the mutations corresponding to the five compounds not found in mucosal polysaccharides resulted in colonization defects. Based on the mutations that caused colonization defects, we determined that both E. coli EDL933 and E. coli MG1655 used arabinose, fucose, and N-acetylglucosamine in the intestine. In addition, E. coli EDL933 used galactose, hexuronates, mannose and ribose, whereas E. coli MG1655 used gluconate and N-acetylneuraminic acid. The colonization defects of six catabolic lesions were found to be additive in E. coli EDL933, but not E. coli MG1655. The data indicate that pathogenic E. coli EDL933 uses sugars that are not used by commensal E. coli MG1655 to colonize the mouse intestine. The results suggest a strategy whereby invading pathogens gain advantage by simultaneously consuming several sugars that may be available because they are not consumed by the commensal intestinal microbiota. Keywords: growth condition: carbon source was mouse cecal mucus E. coli strains were grown on MOPS minimal medium containing 10 mg/ml of mucus or 0.2% glucose in 10 ml standing culture in testtubes and harvested at OD600 = 0.4.
2008-04-25 | E-GEOD-11254 | biostudies-arrayexpress
Project description:Transcriptome profiling of E. coli MG1655, E. coli EDL933, E. coli ECOR26, and E. coli Nissle 1917 grown on mouse cecal mucus as carbon source The carbon sources that support growth of pathogenic E. coli O157:H7 in the mammalian intestine have not previously been investigated. In vivo, pathogenic E. coli EDL933 primarily grows as dispersed single cells within the mucus layer that overlies the mouse cecal epithelium. We therefore compared the pathogen and commensal E. coli MG1655 for their mode of metabolism in vitro on a mixture of the sugars known to be present in cecal mucus and found that the two strains used the thirteen sugars in a similar order and co-metabolized as many as nine sugars at a time. We conducted a systematic mutational analysis of E. coli EDL933 and E. coli MG1655 with lesions in the pathways used for catabolism of thirteen mucus-derived sugars and five other compounds for which the corresponding gene system was induced in the transcriptome of cells grown on cecal mucus. Each of 18 catabolic mutants in both genetic backgrounds was fed to streptomycin-treated mice together with the respective wildtype parent strain and their colonization was monitored in fecal plate counts. None of the mutations corresponding to the five compounds not found in mucosal polysaccharides resulted in colonization defects. Based on the mutations that caused colonization defects, we determined that both E. coli EDL933 and E. coli MG1655 used arabinose, fucose, and N-acetylglucosamine in the intestine. In addition, E. coli EDL933 used galactose, hexuronates, mannose and ribose, whereas E. coli MG1655 used gluconate and N-acetylneuraminic acid. The colonization defects of six catabolic lesions were found to be additive in E. coli EDL933, but not E. coli MG1655. The data indicate that pathogenic E. coli EDL933 uses sugars that are not used by commensal E. coli MG1655 to colonize the mouse intestine. The results suggest a strategy whereby invading pathogens gain advantage by simultaneously consuming several sugars that may be available because they are not consumed by the commensal intestinal microbiota. Keywords: growth condition: carbon source was mouse cecal mucus
2008-04-25 | GSE11254 | GEO
Project description:AbuOun2009 - Genome-scale metabolic network
of Salmonella typhimurium (iMA945)
This model is described in the article:
Genome scale reconstruction
of a Salmonella metabolic model: comparison of similarity and
differences with a commensal Escherichia coli strain.
AbuOun M, Suthers PF, Jones GI,
Carter BR, Saunders MP, Maranas CD, Woodward MJ, Anjum MF.
J. Biol. Chem. 2009 Oct; 284(43):
29480-29488
Abstract:
Salmonella are closely related to commensal Escherichia coli
but have gained virulence factors enabling them to behave as
enteric pathogens. Less well studied are the similarities and
differences that exist between the metabolic properties of
these organisms that may contribute toward niche adaptation of
Salmonella pathogens. To address this, we have constructed a
genome scale Salmonella metabolic model (iMA945). The model
comprises 945 open reading frames or genes, 1964 reactions, and
1036 metabolites. There was significant overlap with genes
present in E. coli MG1655 model iAF1260. In silico growth
predictions were simulated using the model on different carbon,
nitrogen, phosphorous, and sulfur sources. These were compared
with substrate utilization data gathered from high throughput
phenotyping microarrays revealing good agreement. Of the
compounds tested, the majority were utilizable by both
Salmonella and E. coli. Nevertheless a number of differences
were identified both between Salmonella and E. coli and also
within the Salmonella strains included. These differences
provide valuable insight into differences between a commensal
and a closely related pathogen and within different pathogenic
strains opening new avenues for future explorations.
This model is hosted on
BioModels Database
and identified by:
MODEL1507180009.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
2015-07-30 | MODEL1507180009 | BioModels
Project description:Escherichia coli O157 presents a number of specific problems in terms of food safety and public health. It has been found that E. coli O157 is more resistant to a number of the stresses encountered during food production such as heat, pH and osmotic shock. This greater resistance is thought to contribute to the low infectious dose of E. coli O157 (<100 organisms). Moreover, E. coli O157 is associated with debilitating conditions such as haemorrhagic colitis and haemoytic uraemic syndrome, particularly in children and the elderly. We have been studying the stress responses of E. coli O157:H7 (Sakai) and comparing with a commensal strain of E. coli K-12, MG1655. We found that E. coli O157 (Sakai) is more sensitive to oxidative stress than MG1655. A microarray study of these strains treated with sub-lethal concentrations (0.5mg/ml) of menadione revealed big differences in their responses. In E. coli O157 (Sakai), 540 genes responded significantly to the treatment compared to 121 genes in MG1655. One surprising finding from the microarray data was the observation that many iron-transport genes were up-regulated in E. coli O157 (Sakai) whereas relatively few were induced in MG1655 despite the fact that the bacteria were grown in a medium containing ample iron. We speculated that the induction of iron transport genes in an iron-rich medium might have contributed to the enhanced killing of E. coli O157 (Sakai) through triggering of a Fenton reaction. We speculated that the difference in sensitivity to oxidative stress might be due to differences in the intracellular iron content of E. coli O157 and MG1655. We found that E. coli O157 contains ~50% more iron than MG1655 and believe that during oxidative stress, this iron is released by damaged proteins. The greater levels of free iron in E. coli O157 will trigger a greater Fenton reaction that can damage the ferric uptake regulator (Fur), resulting in unregulated iron transport. In MG1655, the lower iron content results in a smaller Fenton reaction, enabling the cellular protection systems to limit damage and protect Fur.
2015-02-22 | GSE36130 | GEO
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 (âpan-genomeâ) 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. Factorial design: Each of four test samples (G 1/2, G3/10, G 4/9, G5) are co-hybridized with two control strain samples (K-12 MG1655 and O157:H7 EDL933). Additional replicate co-hybridizations are included of the two control strain samples (O157:H7 EDL933 vs. K-12 MG1655).
2010-05-26 | E-GEOD-8595 | biostudies-arrayexpress
Project description:Escherichia coli O157 presents a number of specific problems in terms of food safety and public health. It has been found that E. coli O157 is more resistant to a number of the stresses encountered during food production such as heat, pH and osmotic shock. This greater resistance is thought to contribute to the low infectious dose of E. coli O157 (<100 organisms). Moreover, E. coli O157 is associated with debilitating conditions such as haemorrhagic colitis and haemoytic uraemic syndrome, particularly in children and the elderly. We have been studying the stress responses of E. coli O157:H7 (Sakai) and comparing with a commensal strain of E. coli K-12, MG1655. We found that E. coli O157 (Sakai) is more resistant to heat stress than MG1655. A microarray study of these strains subjected to sub-lethal heat-stress at 45M-BM-0C was carried out. In E. coli O157 (Sakai), 380 genes responded significantly to the treatment compared to 410 genes in MG1655. Overnight cultures of E. coli O157 (Sakai) and E. coli K-12 MG1655 were grown in Neidhardt's EZ Rich Defined Medium and diluted 1:100 in 50 ml fresh medium in 125 ml Ehrlenmeyer flasks. The cultures were shaken at 37M-BM-0C until the optical density (OD600) reached 0.4. Each culture was divided into 2 equal parts in identical flasks. One flask flask was transferred to a shaking water bath and incubated at 45M-BM-0C for 10 min; the other flask was incubated at 37M-BM-0C for 10 min. After incubation, the cultures were transferred to 50 mL centrifuge tubes and treated with RNAprotectM-bM-^DM-" to stabilise the mRNA. The experiment was performed 3 times on different days. Six custom-made microarray slides were used in this study; each slide was hybridised with labelled cDNA made from untreated and heated E. coli O157 (Sakai) or MG1655.
2018-03-20 | E-MTAB-5912 | biostudies-arrayexpress
Project description:To study the regulatory outcome of Hfq-mediated sRNA-target interactions, we measured the change in gene expression following overexpression of each of five well-established sRNAs: GcvB, MicA, ArcZ, RyhB and CyaR. For each of the studied sRNAs we applied RNA-seq to two E. coli K-12 MG1655 strains: (1) a WT strain or a strain deleted of the sRNA gene; (2) a strain overexpressing the sRNA, either artificially from a plasmid or from the endogenous sRNA gene by changing the growth condition. For GcvB induction, the E. coli K-12 MG1655 Z1 gcvB::Cm, pZA12-gcvB and the E. coli K-12 MG1655 Z1 gcvB::Cm, pTP-011 strains were used. For MicA overexpression the E. coli K-12 MG1655lacIq pBRplac, pEF21-Hfq and the E. coli K-12 MG1655lacIq pMicA, pEF21-Hfq strains were used. For ArcZ induction the E. coli K-12 MG1655 Z1 arcZ::Cm, pZE12-ArcZ and the E. coli K-12 MG1655 Z1 arcZ::Cm, pJV300 strains were used. For RyhB overexpression the E. coli K-12 MG1655 ryhB::Cm and the E. coli K-12 MG1655 were used. For CyaR induction the E. coli K-12 MG1655 Z1 cyaR::Cm, pZE12-CyaR and the E. coli K-12 MG1655 Z1 cyaR::Cm, pJV300 strains were used. All E. coli strains used in this study were grown overnight in Luria Bertani (LB) medium at 37 °C with shaking (200 r.p.m.), diluted 100-fold in fresh LB medium, and re-grown with shaking at 37 °C to exponential phase, for GcvB (OD600 = 0.3) and for RyhB (OD600 = 0.5), or to stationary phase, for ArcZ WT, ArcZ M1, ArcZ M2 and CyaR (OD600 = 1.0) and for MicA (grown for 6 hr). For induction of ArcZ and GcvB, IPTG was added (1mM, 20 min). MicA was constitutively expressed and further induced at the end of growth with IPTG (1mM, 20 min). For induction of RyhB, the iron chelator 2,2'-Dipyridyl was added (200 μM, 30 min).
2020-03-03 | E-MTAB-8229 | biostudies-arrayexpress
Project description:This entry refers to transcriptome analysis of five E. coli strains: E. coli K-12 MG1655, single deletions of rsd, ssrS, and rpoS, as well as a double deletion of rsd and ssrS, in five growth phases.
2016-06-10 | GSE74809 | GEO