Prolonged cold stress response of Escherichia coli O157 and the role of rpoS

Sinisa Vidovic, Anil K. Mangalappalli-Illathu, Darren R. Korber

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

Phenotypic analyses were performed using an enterohemorrhagic Escherichia coli O157 (EHEC) strain (B-1) and a commensal E. coli K-12 strain, exposed to prolonged cold stress. The EHEC E. coli O157 showed significantly (P< 0.05) higher resistance to cold stress compared to non-pathogenic E. coli K-12 DH5α Further, it was found that RpoS sigma factor plays a significant (P< 0.05) role in the cold stress physiology of the enterohemorrhagic E. coli strain. Using comparative proteomic analysis of hypo-thermally adapted E. coli O157 wild-type and rpoS mutant strains, we identified 21 proteins that were differentially expressed upon cold temperature shifts or rpoS mutation. All identified proteins of cold post-acclimation stimulons fell into two large sub-groups: (i) stress proteins, and (ii) housekeeping proteins. This prolonged cold stress response included proteins involved in mRNA turnover, cell replication efficiency, conditional and post-synthetic modification of membrane lipid bilayers, biosynthetic processes, and the uptake of different sugars. The RpoS sigma factor had no control over the key stress proteins, polynucleotide phosphorylase and elongation factor G, in prolonged stress stimulon. However, RpoS was shown to regulate the expression of proteins involved in homeoviscous adaptation during cold shock, as well as various proteins involved in central metabolic pathways of this food-borne pathogen.

Original languageEnglish (US)
Pages (from-to)163-169
Number of pages7
JournalInternational Journal of Food Microbiology
Volume146
Issue number2
DOIs
StatePublished - Mar 30 2011

Bibliographical note

Funding Information:
The Beef Cattle Research Council , NSERC , and NSERC-CRD are acknowledged for financial support.

Keywords

  • Cold stress response
  • Escherichia coli O157
  • Proteomics
  • Sigma factor

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