Microarray-based transcriptome of  Listeria monocytogenes  adapted to sublethal concentrations of acetic acid, lactic acid, and hydrochloric acid.
Listeria monocytogenes , an important foodborne pathogen, commonly encounters organic acids in food-related environments. The transcriptome of L. monocytogenes L502 was analyzed after adaptation to pH 5 in the presence of acetic acid, lactic acid, or hydrochloric acid (HCl) at 25 °C, representing a condition encountered in mildly acidic ready-to-eat food kept at room temperature. The acid-treated cells were compared with a reference culture with a pH of 6.7 at the time of RNA harvesting. The number of genes and magnitude of transcriptional responses were higher for the organic acids than for HCl. Protein coding genes described for low pH stress, energy transport and metabolism, virulence determinates, and acid tolerance response were commonly regulated in the 3 acid-stressed cultures. Interestingly, the transcriptional levels of histidine and cell wall biosynthetic operons were upregulated, indicating possible universal response against low pH stress in L. monocytogenes. The opuCABCD operon, coding proteins for compatible solutes transport, and the transcriptional regulator sigL were significantly induced in the organic acids, strongly suggesting key roles during organic acid stress. The present study revealed the complex transcriptional responses of L. monocytogenes towards food-related acidulants and opens the roadmap for more specific and in-depth future studies.
Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway.
Girum Tadesse
GT
Tessema
Trond
T
Møretrø
Lars
L
Snipen
Even
E
Heir
Askild
A
Holck
Kristine
K
Naterstad
Lars
L
Axelsson
D019342:Acetic Acid / Q000494:pharmacology*; D000222:Adaptation, Physiological; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006851:Hydrochloric Acid / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000494:pharmacology*; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development; D025341:Principal Component Analysis; D040081:Protein Array Analysis; D019289:Pyruvic Acid / Q000378:metabolism; D015203:Reproducibility of Results; D059467:Transcriptome; D014774:Virulence / Q000187:drug effects / Q000235:genetics
D019344:Lactic Acid; D019289:Pyruvic Acid; D019342:Acetic Acid; D006851:Hydrochloric Acid