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


Kocharunchitt, C and King, T and Gobius, K and Bowman, JP and Ross, T, Global genome response of Escherichia coli O157:H7 Sakai during dynamic changes in growth kinetics induced by an abrupt downshift in water activity, PLoS One, 9, (3) Article e90422. ISSN 1932-6203 (2014) [Refereed Article]


Copyright Statement

Copyright 2014 the Authors-This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

DOI: doi:10.1371/journal.pone.0090422


The present study was undertaken to investigate growth kinetics and time-dependent change in global expression of Escherichia coli O157:H7 Sakai upon an abrupt downshift in water activity (aw). Based on viable count data, shifting E. coli from aw 0.993 to aw 0.985 or less caused an apparent loss, then recovery, of culturability. Exponential growth then resumed at a rate characteristic for the aw imposed. To understand the responses of this pathogen to abrupt osmotic stress, we employed an integrated genomic and proteomic approach to characterize its cellular response during exposure to a rapid downshift but still within the growth range from aw 0.993 to aw 0.967. Of particular interest, genes and proteins with cell envelope-related functions were induced during the initial loss and subsequent recovery of culturability. This implies that cells undergo remodeling of their envelope composition, enabling them to adapt to osmotic stress. Growth at low aw, however, involved up-regulating additional genes and proteins, which are involved in the biosynthesis of specific amino acids, and carbohydrate catabolism and energy generation. This suggests their important role in facilitating growth under such stress. Finally, we highlighted the ability of E. coli to activate multiple stress responses by transiently inducing the RpoE and RpoH regulons to control protein misfolding, while simultaneously activating the master stress regulator RpoS to mediate long-term adaptation to hyperosmolality. This investigation extends our understanding of the potential mechanisms used by pathogenic E. coli to adapt, survive and grow under osmotic stress, which could potentially be exploited to aid the selection and/or development of novel strategies to inactivate this pathogen.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Microbiology
Research Field:Bacteriology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Kocharunchitt, C (Dr Jay Kocharunchitt)
UTAS Author:Bowman, JP (Associate Professor John Bowman)
UTAS Author:Ross, T (Professor Tom Ross)
ID Code:89622
Year Published:2014
Web of Science® Times Cited:25
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2014-03-10
Last Modified:2017-11-06
Downloads:396 View Download Statistics

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