Comparative analysis of transcriptional and physiological responses of Bacillus cereus to organic and inorganic acid shocks.
Comparative phenotype and transcriptome analyses were performed with Bacillus cereus ATCC 14579 exposed to pH 5.5 set with different acidulants including hydrochloric acid (HCl), lactic acid (HL) and acetic acid (HAc). Phenotypes observed included a decreased growth rate (with HCl), bacteriostatic and bactericidal conditions, with 2mM undissociated HAc or HL, and 15mM undissociated HAc, respectively. In the latter condition a concomitant decrease in intracellular ATP levels was observed. The transcriptome analyses revealed general and specific responses to the acidulants used. The general acid stress response includes modulation of pyruvate metabolism with activation of the butanediol fermentation pathway, and an oxidative stress response that was, however, more extensive in the bacteriostatic and bactericidal conditions. HL-specific and HAc-specific responses include modulation of metabolic pathways for amino acid metabolism. Activation of lactate, formate, and ethanol fermentation pathways, alternative electron-transport chain components and fatty acid biosynthesis genes was noted in the presence of 15mM undissociated HAc. In conclusion, our study has provided insights in phenotype-associated, and general and acidulant-specific responses in B. cereus.
Mols
Maarten
M
Top Institute Food and Nutrition, Wageningen, The Netherlands; Laboratory of Food Microbiology, Wageningen University and Research Centre, The Netherlands.
van Kranenburg
Richard
R
Tempelaars
Marcel H
MH
van Schaik
Willem
W
Moezelaar
Roy
R
Abee
Tjakko
T
D000143:Acids; D000255:Adenosine Triphosphate / Q000378:metabolism; D001409:Bacillus cereus / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology*; D005285:Fermentation; D005516:Food Microbiology; D015870:Gene Expression; D020869:Gene Expression Profiling; D005798:Genes, Bacterial; D006863:Hydrogen-Ion Concentration; D010641:Phenotype; D013312:Stress, Physiological
D000143:Acids; D000255:Adenosine Triphosphate