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Global genome response of Escherichia coli O157:H7 Sakai during dynamic changes in growth kinetics induced by an abrupt temperature downshift

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posted on 2023-05-18, 05:33 authored by King, T, Chawalit KocharunchittChawalit Kocharunchitt, Gobius, K, John BowmanJohn Bowman, Thomas RossThomas Ross
Escherichia coli O157:H7 is a mesophilic food-borne pathogen. We investigated the growth kinetics of E. coli O157:H7 Sakai during an abrupt temperature downshift from 35°C to either 20°C, 17°C, 14°C or 10°C; as well as the molecular mechanisms enabling growth after cold stress upon an abrupt downshift from 35°C to 14°C in an integrated transcriptomic and proteomic analysis. All downshifts caused a lag period of growth before growth resumed at a rate typical of the post-shift temperature. Lag and generation time increased with the magnitude of the shift or with the final temperature, while relative lag time displayed little variation across the test range. Analysis of time-dependent molecular changes revealed, in keeping with a decreased growth rate at lower temperature, repression of genes and proteins involved in DNA replication, protein synthesis and carbohydrate catabolism. Consistent with cold-induced remodelling of the bacterial cell envelope, alterations occurred in the expression of genes and proteins involved in transport and binding. The RpoS regulon exhibited sustained induction confirming its importance in adaptation and growth at 14°C. The RpoE regulon was transiently induced, indicating a potential role for this extracytoplasmic stress response system in the early phase of low temperature adaptation during lag phase. Interestingly, genes previously reported to be amongst the most highly up-regulated under oxidative stress were consistently down-regulated. This comprehensive analysis provides insight into the molecular mechanisms operating during adaptation of E. coli to growth at low temperature and is relevant to its physiological state during chilling in foods, such as carcasses.

Funding

Meat and Livestock Australia

History

Publication title

PLoS One

Volume

9

Issue

6

Article number

e99627

Number

e99627

Pagination

1-13

ISSN

1932-6203

Department/School

Tasmanian Institute of Agriculture (TIA)

Publisher

Public Library of Science

Place of publication

United States of America

Rights statement

Licensed under Creative Commons Attribution 3.0 Unported (CC BY 3.0) http://creativecommons.org/licenses/by/3.0/

Repository Status

  • Open

Socio-economic Objectives

Expanding knowledge in the biological sciences

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