Proteomics analysis of Listeria monocytogenes ATCC 19115 in response to simultaneous triple stresses

Listeria monocytogenes can cause listeriosis in humans through consumption of contaminated food. L. monocytogenes can adapt and grow in a vast array of physiochemical stresses in the food production environment. In this study, we performed a proteomics strategy in order to investigate how L. monocytogenes survives with a simultaneous exposure to low pH, high salinity and low temperature. The results showed that the adaptation processes mainly affected the biochemical pathways related to protein synthesis, oxidative stress, cell wall and nucleotide metabolism. Interestingly, enzymes involved in the carbohydrate metabolism of energy, such as glycolysis and pentose phosphate pathway, were derepressed due to the down-regulation of CodY, a global transcriptional repressor. The down-regulation of CodY, together with the up-regulation of carbohydrate metabolism enzymes, likely leads to the accumulation of pyruvate and further to the activation of fatty acid synthesis pathway. Proteomics profiling offered a better understanding of the physiological responses of this pathogen to adapt to harsh environment and would hopefully contribute to improving the food-processing and storage methods.