Role of cold shock proteins in growth of Listeria monocytogenes under cold and osmotic stress conditions.
The gram-positive bacterium Listeria monocytogenes is a food-borne pathogen of both public health and food safety significance. It possesses three small, highly homologous protein members of the cold shock protein (Csp) family. We used gene expression analysis and a set of mutants with single, double, and triple deletions of the csp genes to evaluate the roles of CspA, CspB, and CspD in the cold and osmotic (NaCl) stress adaptation responses of L. monocytogenes. All three Csps are dispensable for growth at optimal temperature (37 degrees C). These proteins are, however, required for efficient cold and osmotic stress tolerance of this bacterium. The hierarchies of their functional importance differ, depending on the environmental stress conditions: CspA>CspD>CspB in response to cold stress versus CspD>CspA/CspB in response to NaCl salt osmotic stress. The fact that Csps are promoting L. monocytogenes adaptation against both cold and NaCl stress has significant implications in view of practical food microbial control measures. The combined or sequential exposure of L. monocytogenes cells to these two stresses in food environments might inadvertently induce cross-protection responses.
Schmid
Barbara
B
Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstr. 272, CH-8057 Zurich, Switzerland.
Klumpp
Jochen
J
Raimann
Eveline
E
Loessner
Martin J
MJ
Stephan
Roger
R
Tasara
Taurai
T
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D003080:Cold Temperature; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics / Q000502:physiology*; D008089:Listeria monocytogenes / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D016415:Sequence Alignment
D001426:Bacterial Proteins; C088098:CspD protein, bacteria; D006360:Heat-Shock Proteins; C062260:cold shock protein CS7.4, Bacteria; C077188:cold-shock protein CspB, Bacteria