Article

Growth-related variations in theBacillus cereus secretome

Institut National de la Recherche Agronomique (INRA), Génétique microbienne et Environnement, Guyancourt, France.
PROTEOMICS (Impact Factor: 3.81). 05/2007; 7(10):1719-28. DOI: 10.1002/pmic.200600502
Source: PubMed

ABSTRACT

Using 2-DE, transcriptional gene fusions and cell cytotoxicity assays, we followed changes in the Bacillus cereus strain ATCC14579 secretome, gene expression and culture supernatant cytotoxicity from the end of the vegetative phase up to 5 h after entry into the stationary phase. The concentration of each of the 22 proteins in the culture supernatant was determined at various times. In addition, the stability of the proteins was studied. Fifteen of these proteins, including 14 members of the virulence regulon PlcR, were known or predicted to be secreted. All of the secreted proteins reached a maximum concentration during early stationary phase, but there were significant differences in the kinetics of their concentrations. The time courses of protein concentrations were in agreement with gene expression data, except for cytotoxin CytK, which was unstable, and for the metalloprotease InhA1. Supernatant cytoxicity also peaked in early stationary phase, and the kinetics of cytotoxicity paralleled the time course of concentration of the PlcR-controlled toxin, CytK. Our concomitant study of the time course of protein concentrations, gene expression and supernatant cytotoxicity reveals that the pathogenic potential of B. cereus peaks during the transition state. It also suggests that there is diversity in the regulation of gene expression within the PlcR regulon.

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Available from: Stéphane Perchat, Aug 28, 2014
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    • "In the early stationary phase, B. cereus produces several extracellular compounds (degradative enzymes, cytotoxic factors and cell surface proteins) that might contribute to virulence [8], [9], [10], [11], [12]. However, the mechanisms leading to the various pathologies of B. cereus are not completely elucidated. "
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    Preview · Article · Feb 2013 · PLoS ONE
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    • "Moreover, enterotoxins Nhe, Hbl, and CytK are all toxic for Vero cells (Wehrle et al., 2009), so a positive cytotoxicity assay requires further analysis to reveal which specific enterotoxins the B. cereus strain produces. Similar to the liquid chromatography mass spectrometry (LC-MS) assay for B. cereus emetic toxin cereulide (Delbrassinne et al., 2011), all B. cereus enterotoxins can be detected by mass spectrometry assays (Gilois et al., 2007). The strong points of these methods include their high specificity and sensitivity, while the main drawbacks are the extensive, labor-intensive sample preparation and high investment, running, and maintenance costs. "
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