Analysis of acid-stressed Bacillus cereus reveals a major oxidative response and inactivation-associated radical formation
Article first published online: 13 JAN 2010
© 2010 Society for Applied Microbiology and Blackwell Publishing Ltd
Volume 12, Issue 4, pages 873–885, April 2010
How to Cite
Mols, M., Van Kranenburg, R., Van Melis, C. C. J., Moezelaar, R. and Abee, T. (2010), Analysis of acid-stressed Bacillus cereus reveals a major oxidative response and inactivation-associated radical formation. Environmental Microbiology, 12: 873–885. doi: 10.1111/j.1462-2920.2009.02132.x
- Issue published online: 29 MAR 2010
- Article first published online: 13 JAN 2010
- Received 10 July, 2009; accepted 15 November, 2009.
Acid stress resistance of the food-borne human pathogen Bacillus cereus may contribute to its survival in acidic environments, such as encountered in soil, food and the human gastrointestinal tract. The acid stress responses of B. cereus strains ATCC 14579 and ATCC 10987 were analysed in aerobically grown cultures acidified to pH values ranging from pH 5.4 to pH 4.4 with HCl. Comparative phenotype and transcriptome analyses revealed three acid stress-induced responses in this pH range: growth rate reduction, growth arrest and loss of viability. These physiological responses showed to be associated with metabolic shifts and the induction of general stress response mechanisms with a major oxidative component, including upregulation of catalases and superoxide dismutases. Flow cytometry analysis in combination with the hydroxyl (OH·) and peroxynitrite (ONOO-)-specific fluorescent probe 3′-(p-hydroxyphenyl) fluorescein (HPF) showed excessive radicals to be formed in both B. cereus strains in bactericidal conditions only. Our study shows that radicals can indicate acid-induced malfunctioning of cellular processes that lead to cell death.