Project description:A genome reduced E. coli strain MDS42ΔgalK::Ptet-gfp-kan were applied for the comparative transcriptome analysis. Genome-wide transcriptional changes under high osmotic prresure, high temperature condition and starvation were evaluated.
Project description:Archer2011 - Genome-scale metabolic model of
Escherichia coli (iCA1273)
This model is described in the article:
The genome sequence of E.
coli W (ATCC 9637): comparative genome analysis and an improved
genome-scale reconstruction of E. coli.
Archer CT, Kim JF, Jeong H, Park JH,
Vickers CE, Lee SY, Nielsen LK.
BMC Genomics 2011; 12: 9
Abstract:
BACKGROUND: Escherichia coli is a model prokaryote, an
important pathogen, and a key organism for industrial
biotechnology. E. coli W (ATCC 9637), one of four strains
designated as safe for laboratory purposes, has not been
sequenced. E. coli W is a fast-growing strain and is the only
safe strain that can utilize sucrose as a carbon source.
Lifecycle analysis has demonstrated that sucrose from sugarcane
is a preferred carbon source for industrial bioprocesses.
RESULTS: We have sequenced and annotated the genome of E. coli
W. The chromosome is 4,900,968 bp and encodes 4,764 ORFs. Two
plasmids, pRK1 (102,536 bp) and pRK2 (5,360 bp), are also
present. W has unique features relative to other sequenced
laboratory strains (K-12, B and Crooks): it has a larger genome
and belongs to phylogroup B1 rather than A. W also grows on a
much broader range of carbon sources than does K-12. A
genome-scale reconstruction was developed and validated in
order to interrogate metabolic properties. CONCLUSIONS: The
genome of W is more similar to commensal and pathogenic B1
strains than phylogroup A strains, and therefore has greater
utility for comparative analyses with these strains. W should
therefore be the strain of choice, or 'type strain' for group
B1 comparative analyses. The genome annotation and tools
created here are expected to allow further utilization and
development of E. coli W as an industrial organism for
sucrose-based bioprocesses. Refinements in our E. coli
metabolic reconstruction allow it to more accurately define E.
coli metabolism relative to previous models.
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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 (“pan-genome”) 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. Keywords: Comparative genomic hybridizations