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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Cell. Infect. Microbiol. | doi: 10.3389/fcimb.2019.00263

The Salmonella specific, σE-regulated, STM1250 and AgsA, function with the sHsps IbpA and IbpB, to counter oxidative stress and survive macrophage killing

 Claire L. Hews1*, Emily J. Pritchard1 and  Gary Rowley1*
  • 1University of East Anglia, United Kingdom

The host presents an array of environments which induce bacterial stress including changes in pH, antimicrobial compounds and reactive oxygen species. The bacterial envelope sits at the interface between the intracellular and extracellular environment and its maintenance is essential for Salmonella cell viability under a range of conditions, including during infection. In this study, we aimed to understand the contribution of the σH- and σE-regulated small heat shock proteins IbpA, IbpB and AgsA and the putative σE-regulated stress response protein STM1250 to the Salmonella envelope stress response. Due to shared sequence identity, regulatory overlap, and the specificity of STM1250 and AgsA to Salmonella sp., we hypothesised that functional overlap exists between these four stress response proteins, which might afford a selective advantage during Salmonella exposure to stress. We present here new roles for three small heat shock proteins and a putative stress response protein in Salmonella that are not limited to heat shock. We have shown that, compared to WT, a quadruple mutant is significantly more sensitive to hydrogen peroxide, has a lower minimum bactericidal concentration to the cationic antimicrobial peptide polymyxin B, and is attenuated in macrophages.

Keywords: Salmonella, envelope stress, Oxidative Stress, RpoE, sHsps, small heat shock proteins

Received: 02 Apr 2019; Accepted: 04 Jul 2019.

Edited by:

Jyl S. Matson, University of Toledo, United States

Reviewed by:

Dan Drecktrah, University of Montana, United States
Travis Bourret, Creighton University, United States
James M. Slauch, University of Illinois at Urbana-Champaign, United States  

Copyright: © 2019 Hews, Pritchard and Rowley. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Miss. Claire L. Hews, University of East Anglia, Norwich, United Kingdom, C.Hews@uea.ac.uk
Dr. Gary Rowley, University of East Anglia, Norwich, United Kingdom, G.Rowley@uea.ac.uk