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

• Published in: International journal of food microbiology Vol. 320; p. 108504
• Main Authors: Crespo Tapia, Natalia, Dorey, Amber L., Gahan, Cormac G.M., den Besten, Heidy M.W., O'Byrne, Conor P., Abee, Tjakko
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 02.05.2020; Elsevier BV
• Subjects: Acid stress; Adhesion assay; Biofilm; Biofilms; C2Bbe1 cell line; Carbon; Carbon source; Carbon sources; Cell activation; Cell lines; Fluorescence; Fluorescence microscopy; Fluorescence spectroscopy; Food; Food chains; Food preservation; Food processing; Glucose; Glycerol; Heat stress; Invasion assay; Lactose; Listeria; Listeria monocytogenes; Phenotypes; SigB; Sigma B; Sigma factor; Stress; Stress response; Virulence; Western blotting; Invasion assay; Adhesion assay; Virulence; Listeria monocytogenes; Glycerol; Glucose; Acid stress; Stress; Lactose; C2Bbe1 cell line; SigB; Sigma B; Biofilm; Carbon source; Heat stress; Stress response
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2019.108504

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. •Lactose induces high SigB activity in L. monocytogenes EGDe.•Lactose enhances L. monocytogenes EGDe resistance to heat and acid stress.•Lactose increases biofilm formation and number of culturable biofilm cells.•Lactose enhances adhesion/invasion capacity of Caco-2-derived C2Bbe1 cell lines.