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Comparative genomic hybridization of environmental Escherichia coli isolates indicates highly conserved ecophysiology

ABSTRACT: 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)

ORGANISM(S): Escherichia coli

SUBMITTER: Thomas Egli

PROVIDER: E-GEOD-6407 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Comparative genomic hybridization and physiological characterization of environmental isolates indicate that significant (eco-)physiological properties are highly conserved in the species Escherichia coli.

Ihssen Julian J Grasselli Elena E Bassin Claudio C François Patrice P Piffaretti Jean-Claude JC Köster Wolfgang W Schrenzel Jacques J Egli Thomas T

Microbiology (Reading, England) 20070701 Pt 7

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 o ...[more]

PMID: 17600050

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Dataset Information

Comparative genomic hybridization of environmental Escherichia coli isolates indicates highly conserved ecophysiology

Publications

Comparative genomic hybridization and physiological characterization of environmental isolates indicate that significant (eco-)physiological properties are highly conserved in the species Escherichia coli.

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