Listeria monocytogenes Biofilm Adaptation to Different Temperatures Seen Through Shotgun Proteomics

Abstract

Listeria monocytogenes is a foodborne pathogen that can cause invasive severe human illness (listeriosis) in susceptible patients. Most human listeriosis cases appear to be caused by consumption of refrigerated ready-to-eat foods. Although initial contamination levels in foods are usually low, the ability of these bacteria to survive and multiply at low temperatures allows it to reach levels high enough to cause disease. This study explores the set of proteins that might have an association with L. monocytogenes adaptation to different temperatures. Cultures were grown in biofilm, the most widespread mode of growth in natural and industrial realms. Protein extractions were performed from three different growth temperatures (10, 25, and 37°C) and two growth phases (early stage and mature biofilm). L. monocytogenes subproteomes were targeted using three extraction methods: trypsin-enzymatic shaving, biotin-labeling and cell fractionation. The different subproteomes obtained were separated and analyzed by shotgun proteomics using high-performance liquid chromatography combined with tandem mass spectrometry (LC-OrbiTrap LTQVelos, ThermoFisher Scientific). A total of 141 (biotinylation), 98 (shaving) and 910 (fractionation) proteins were identified. Throughout the 920 unique proteins identified, many are connected to basic cell functions, but some are linked with thermoregulation. We observed some noteworthy protein abundance shifts associated with the major adaptation to cold mechanisms present in L. monocytogenes , namely: the role of ribosomes and the stressosome with a higher abundance of the general stress protein Ctc (Rl25) and the general stress transcription factor sigma B (σ B ), changes in cell fluidity and motility seen by higher levels of foldase protein PrsA2 and flagellin (FlaA), the uptake of osmolytes with a higher abundance of glycine betaine (GbuB) and carnitine transporters (OpucA), and the relevance of the overexpression of chaperone proteins such as cold shock proteins (CspLA and Dps). As for 37°C, we observed a significantly higher percentage of proteins associated with transcriptional or translational activity present in higher abundance upon comparison with the colder settings. These contrasts of protein expression throughout several conditions will enrich databases and help to model the regulatory circuitry that drives adaptation of L. monocytogenes to environments.

The Uptake and Release of Amino Acids by Staphylococcus aureus at Mid-Exponential and Stationary Phases and Their Corresponding Responses to Changes in Temperature, pH and Osmolality

“…Bacteria have been previously reported to produce secondary metabolites and small molecules in the stationary phase of growth (Martin and Liras, 1989;. These function as signaling molecules to start the process of biofilm induction or inhibiting the growth of other organisms sharing the same environments Santos et al, 2019). At stationary phase, the population density increases significantly, and the production of extracellular molecules that participate in cell-cell communications (quorum sensing) show a high correlation with cell density (Beenken et al, 2004;Resch et al, 2006).…”

Antimicrobial Effects of Berries on Listeria monocytogenes

“…Listeria monocytogenes is a foodborne pathogen that can cause invasive severe human illness (listeriosis) in susceptible patients. Most human listeriosis cases appear to be caused by consumption of refrigerated ready-to-eat foods [3]. In the European Union (EU), 1763 confirmed human cases of listeriosis were reported in 2013 by 27 member states.…”

Biofilm formation and extracellular microvesicles—The way of foodborne pathogens toward resistance

“…Santos et al [54] investigated influence of L. monocytogenes adaptation to different temperatures (10,25, and 37°C) by use of quantitative proteomics. This pathogen can survive and multiply at low temperatures and it can reach concentration levels in food that are high enough to cause disease outbreak.…”

“…Based on published data, Pizzaro-Cerdá and Cossard [132] gave an omics profile of this food pathogen. Unfortunately, in above discussed article by Santos et al [54], neither LLO, nor InlB were taken in consideration, and possible role of these two virulence factors in biofilm formation and virulence of biofilm growing L. monocytogenes still has to be explored.…”