Small Bacillus cereus ATCC 14579 subpopulations are responsible for cytotoxin K production
Article first published online: 7 JAN 2013
© 2012 Ghent University © 2012 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 114, Issue 3, pages 899–906, March 2013
How to Cite
Ceuppens, S., Timmery, S., Mahillon, J., Uyttendaele, M. and Boon, N. (2013), Small Bacillus cereus ATCC 14579 subpopulations are responsible for cytotoxin K production. Journal of Applied Microbiology, 114: 899–906. doi: 10.1111/jam.12096
- Issue published online: 18 FEB 2013
- Article first published online: 7 JAN 2013
- Accepted manuscript online: 7 DEC 2012 07:57AM EST
- Manuscript Accepted: 27 NOV 2012
- Manuscript Revised: 22 NOV 2012
- Manuscript Received: 6 AUG 2012
- Special Research Funds of Ghent University. Grant Number: B/09036/02
- Bacillus cereus ;
- cytotoxin K (CytK);
- toxin gene expression;
- virulent subpopulation
Bacillus cereus diarrhoeal food poisoning can be caused by several potential enterotoxins, including the nonhaemolytic enterotoxin (Nhe), haemolysin BL (Hbl) and cytotoxin K (CytK). To get more insights into the CytK expression, a fluorescent reporter strain was created for CytK expression.
Bacillus cereus ATCC 14579 was used as the reporter strain that contained the cyan fluorescent protein (CFPopt) gene under control of the cytK promoter. Transcription of enterotoxin genes nheB, hblC and cytK was assessed by messenger RNA analysis (RT-qPCR), and their full expression was assessed by immunological protein detection in the case of Nhe and Hbl and fluorescence microscopy in the case of CytK, using the reporter gene CFPopt.
Transcription of enterotoxins Nhe, Hbl and CytK showed similar kinetics with a peak during the late exponential growth phase. Toxin expression of the reporter strain was unaltered in comparison with the wild type. However, fluorescence, and thus CytK expression, only occurred in a small (1–2%) portion of the cell population.
These results suggest that a small subpopulation of B. cereus ATCC 14579 is responsible for CytK production in a homogeneous monoculture.
Significance and Impact of the Study
Future research is warranted to determine whether genetically homogeneous B. cereus populations utilize differential gene expression for other toxins and virulence genes than CytK and whether this also applies to other B. cereus strains. If so, differential expression of toxin genes could be used by these bacteria to increase the fitness and survival chances of their population by diversification and specialization into different subpopulations.