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Inhibition of cereulide toxin synthesis by emetic Bacillus cereus via long-chain polyphosphates.
- Source :
-
Applied and environmental microbiology [Appl Environ Microbiol] 2011 Feb; Vol. 77 (4), pp. 1475-82. Date of Electronic Publication: 2010 Dec 17. - Publication Year :
- 2011
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Abstract
- Severe intoxications caused by the Bacillus cereus emetic toxin cereulide can hardly be prevented due to the ubiquitous distribution and heat resistance of spores and the extreme thermal and chemical stability of cereulide. It would therefore be desirable to inhibit cereulide synthesis during food manufacturing processes or in prepared foods, which are stored under time-temperature abuse conditions. Toward this end, the impacts of three long-chain polyphosphate (polyP) formulations on growth and cereulide production were examined. The inhibition was dependent on the concentration and the type of the polyP blend, indicating that polyPs and not the orthophosphates were effective. Quantitative PCR (qPCR) monitoring at sublethal concentrations revealed that polyPs reduced the transcription of ces nonribosomal peptide synthetase (NRPS) genes by 3- to 4-fold along with a significantly reduced toxin production level. At lower concentrations, toxin synthesis was decreased, although the growth rate was not affected. These data indicate a differential effect on toxin synthesis independent of growth inhibition. The inhibition of toxin synthesis in food was also observed. Despite the growth of B. cereus, toxin synthesis was reduced by 70 to 100% in two model food systems (reconstituted infant food and oat milk), which were analyzed with HEp-2 cell culture assays and high-performance liquid chromatography (HPLC)/electrospray ionization-time of flight mass spectrometry (ESI-TOF-MS). Accordingly, ces promoter activity was strongly downregulated, as visualized by using a lux-based reporter strain. These data illustrate the potential of polyphosphate formulations to reduce the risk of cereulide synthesis in food and may contribute to targeted hurdle concepts.
- Subjects :
- Bacillus cereus drug effects
Bacillus cereus growth & development
Chromatography, High Pressure Liquid
Depsipeptides genetics
Depsipeptides metabolism
Down-Regulation drug effects
Food Industry methods
Food Microbiology methods
Peptide Biosynthesis, Nucleic Acid-Independent drug effects
Peptide Synthases genetics
Polymerase Chain Reaction
Promoter Regions, Genetic
Spectrometry, Mass, Electrospray Ionization
Bacillus cereus genetics
Bacillus cereus metabolism
Bacterial Toxins biosynthesis
Depsipeptides biosynthesis
Peptide Synthases metabolism
Polyphosphates pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 1098-5336
- Volume :
- 77
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Applied and environmental microbiology
- Publication Type :
- Academic Journal
- Accession number :
- 21169440
- Full Text :
- https://doi.org/10.1128/AEM.02259-10