Different carbon sources result in differential activation of sigma B and stress resistance in Listeria monocytogenes

Natalia Crespo Tapia, Amber L. Dorey, Cormac G.M. Gahan, Heidy M.W. den Besten, Conor P. O'Byrne, Tjakko Abee*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Listeria monocytogenes is an important food-borne pathogen that is ubiquitous in the environment. It is able to utilize a variety of carbon sources, to produce biofilms on food-processing surfaces and to survive food preservation–associated stresses. In this study, we investigated the effect of three common carbon sources, namely glucose, glycerol and lactose, on growth and activation of the general stress response Sigma factor, SigB, and corresponding phenotypes including stress resistance. A fluorescent reporter coupled to the promoter of lmo2230, a highly SigB-dependent gene, was used to determine SigB activation via quantitative fluorescence spectroscopy. This approach, combined with Western blotting and fluorescence microscopy, showed the highest SigB activation in lactose grown cells and lowest in glucose grown cells. In line with this observation, lactose grown cells showed the highest resistance to lethal heat and acid stress, the highest biofilm formation, and had the highest adhesion/invasion capacity in Caco-2-derived C2Bbe1 cell lines. Our data suggest that lactose utilisation triggers a strong SigB dependent stress response and this may have implications for the resistance of L. monocytogenes along the food chain.

Original languageEnglish
Article number108504
JournalInternational Journal of Food Microbiology
Volume320
DOIs
Publication statusPublished - 2 May 2020

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Keywords

  • Acid stress
  • Adhesion assay
  • Biofilm
  • C2Bbe1 cell line
  • Carbon source
  • Glucose
  • Glycerol
  • Heat stress
  • Invasion assay
  • Lactose
  • Listeria monocytogenes
  • SigB
  • Sigma B
  • Stress
  • Stress response
  • Virulence

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