title: Differential gene expression of Listeria monocytogenes during high hydrostatic pressure processing.
abstract: High hydrostatic pressure processing (HPP) is currently being used as a treatment for certain foods to control the presence of food-borne pathogens, such as Listeria monocytogenes. Genomic microarray analysis was performed to determine the effects of HPP on L. monocytogenes in order to understand how it responds to mechanical stress injury. Reverse transcriptase PCR analysis of tufA and rpoC indicated that the reduction of mRNA expression in HPP-treated cells was dependent on intensity and time of the treatment. Treatments of 400 and 600 MPa for 5 min on cells in the exponential growth phase, though leading to partial or complete cellular inactivation, still resulted in measurable relative differential gene expression. Gene set enrichment analysis indicated that HPP induced increased expression of genes associated with DNA repair mechanisms, transcription and translation protein complexes, the septal ring, the general protein translocase system, flagella assemblage and chemotaxis, and lipid and peptidoglycan biosynthetic pathways. On the other hand, HPP appears to suppress a wide range of energy production and conversion, carbohydrate metabolism and virulence-associated genes accompanied by strong suppression of the SigB and PrfA regulons. HPP also affected genes controlled by the pleotrophic regulator CodY. HPP-induced cellular damage appears to lead to increased expression of genes linked to sections of the cell previously shown in bacteria to be damaged or altered during HPP exposure and suppression of gene expression associated with cellular growth processes and virulence.
authors.affiliation: Australian Food Safety Centre of Excellence, Tasmanian Institute of Agricultural Research, School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart, Tasmania, 7001, Australia.
authors.forename: John P
authors.initials: JP
authors.lastname: Bowman
authors.affiliation: Australian Food Safety Centre of Excellence, Tasmanian Institute of Agricultural Research, School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart, Tasmania, 7001, Australia.
authors.forename: Claudio R
authors.initials: CR
authors.lastname: Bittencourt
authors.affiliation: Australian Food Safety Centre of Excellence, Tasmanian Institute of Agricultural Research, School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart, Tasmania, 7001, Australia.
authors.forename: Tom
authors.initials: T
authors.lastname: Ross
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D050260:Carbohydrate Metabolism; D002473:Cell Wall / Q000235:genetics; D015536:Down-Regulation; D005293:Ferritins / Q000235:genetics; D005516:Food Microbiology; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics; D006874:Hydrostatic Pressure; D008089:Listeria monocytogenes / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D010454:Peptide Termination Factors / Q000235:genetics; D018085:Regulon / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012808:Sigma Factor / Q000235:genetics; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D010454:Peptide Termination Factors; C480945:SigB protein, Listeria monocytogenes; D012808:Sigma Factor; C418864:ferritin-like protein, Listeria; D005293:Ferritins