Bacillus cereus
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ABSTRACT:
PROVIDER: PRJNA1082486 | ENA |
REPOSITORIES: ENA
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Project description:Bacillus cereus is the second leading cause of collective food poisoning in France. B. cereus is also associated with severe clinical infections leading to patient death in 10% of the cases. The emergence of B. cereus as a foodborne and opportunistic pathogen has intensified the need to distinguish strains of public health concern. In this work, by performing a screen on a large collection of B. cereus strains of varying pathogenic potential, we identified genetic determinants capable of discriminating B. cereus strains inducing negative clinical outcomes. The combination of 4 biomarkers is sufficient to accurately discern clinical strains from harmless strains. Three of the biomarkers are located on the chromosome, with a fourth one identifying a plasmid carried by most pathogenic strains. A 50 kbp region of this plasmid promotes the virulence potential of these strains and could thus be defined as a new pathogenicity island of B. cereus. These new findings help in the understanding of B. cereus pathogenic potential and complexity and may provide tools for a better assessment of the risks associated with B. cereus contamination to improve patient health and food safety.
2022-01-12 | GSE171128 | GEO
Project description:Extracellular vesicles (EVs) from Gram-positive bacteria have gained considerable importance as a novel transport system of virulence factors in host-pathogen interactions. Bacillus cereus is a Gram-positive human pathogen, causing gastrointestinal toxemia as well as local and systemic infections. The pathogenicity of the B. cereus has been linked to a collection of virulence factors and exotoxins. Nevertheless, the exact mechanism of virulence factor secretion and delivery to target cells is poorly understood. Here, we investigate the production and characterization of enterotoxin-associated EVs from the enteropathogenic B. cereus strain NVH0075-95 by using a proteomics approach and studied their interaction with human host cells in vitro. Proteomic analysis of B. cereus EVs revealed virulence-associated factors, such as sphingomyelinase, phospholipase C, and the three-component enterotoxin Nhe. The detection of Nhe subunits was confirmed by immunoblotting, showing that the low abundant subunit NheC was exclusively detected in EVs as compared to vesicle-free supernatant. Fusion of B. cereus EVs with the plasma membrane of intestinal epithelial Caco2 cells represent entry routes for delivery of Nhe components to host cells, which was assessed by confocal microscopy. B. cereus EVs also elicit an inflammatory response in human monocytes and contribute to erythrocyte lysis via a cooperative interaction of enterotoxin Nhe and sphingomyelinase. Our results provide insights into the interaction of EVs from B. cereus with human host cells and add a new layer of complexity to our understanding of multicomponent enterotoxin assembly, offering new opportunities to decipher molecular processes involved in disease development.
2023-07-20 | PXD041561 | Pride
Project description:RNA-seq experiment comparing the transcriptomes of Bacillus cereus G9241 WT to B. cereus G9241 ∆pBCXO1 when cultured both 37 and 25 degree celsius. B. cereus G9241 is a B. cereus sensu stricto strain that was isolated from a welder with and anthrax-like illness. B. cereus G9241 carries the plasmids pBCXO1 and pBC210. pBCX01 has 99.6% sequence identity to pXO1 carried by Bacillus anthracis and encodes the tripartite anthrax toxin genes and atxA, a mammalian virulence transcriptional regulator. B. cereus G9241 WT and B. cereus G9241 ∆pBCXO1 were cultured to exponential phase at either 37 or 25 degree celsius before samples were taken for RNA extraction, library prep and sequencing.
2023-05-13 | E-MTAB-12883 | biostudies-arrayexpress
Project description:The Bacillus cereus ATCC 14579 alternative σ factor σZ and its putative regulon have been characterized. σZ shows overall similarity with ECF σ factors and sigZ constitutes an operon together with asfZ encoding its putative anti-σ factor. Expression analysis revealed sigZ to be induced by an array of stresses, including exposure to ethanol, alkaline pH and heat shock, and a typical promoter binding site for the sigZ-operon was identified by 5’RACE. Phenotypic characterization of B. cereus ATCC 14579 and its sigZ-deletion strain revealed diminished growth performance and sporulation capacity. The σZ-regulon was successfully established by transcriptome analysis of a nisin inducible sigZ-overexpression strain. Overexpression of sigZ was shown to affect expression of 42 genes, including 33 genes encoding proteins located in the extracytoplasm. The identified σZ regulon contained genes encoding proteins situated in the extracytoplasm involved in cell surface modifications and transport. The regulation of genes encoding cell surface modification proteins implies σZ to be involved in the regulation of interaction of B. cereus ATCC 14579 with its environments, which includes human intestinal cells, possibly influencing its virulence status. Keywords: Comparative transcriptome study
2008-05-11 | GSE9860 | GEO
Project description:Comparison of the Bacillus cereus with overexpressed Bacillus subtilis ComK (Bacillus cereus pNWcomKBsu) vs Bacillus cereus carrying empty plasmid (Bacillus cereus pNW33N)
2011-07-28 | GSE27265 | GEO
Project description:The alternative sigma factor sigmaB has an important role in the acquisition of stress-resistance in many gram-positive bacteria. In the foodborne pathogen Bacillus cereus sigmaB is activated strongly upon a heat shock and other stress conditions. Here we describe the identification of the set of sigmaB-regulated genes in B. cereus by DNA microarray analysis of the transcriptome upon a mild heat shock. A total of 24 genes could be identified as being sigmaB-dependent as witnessed by (i) significantly lower expression-levels of these genes in mutants deleted for sigB and rsbY (encoding the alternative sigma factor sigmaB and a PP2C phosphatase that acts as a crucial positive regulator of sigmaB-activity, respectively) than in the parental strain B. cereus ATCC 14579, and (ii) increased expression of these genes upon a heat shock. Newly identified members of the sigmaB-regulon of B. cereus include an ECF-sigma factor (sigmaZ), a histidine kinase and two genes that have predicted functions in spore germination. Our data indicate that the sigmaB-regulon of B. cereus is considerably smaller than that of other gram-positive bacteria. This appears to be in line with phylogenetic analyses of sigmaB in which sigmaB in the B. cereus group was suggested to be close to the ancestral form of sigmaB in gram-positive bacteria. Keywords: stress response, comparative genomics
2007-04-10 | GSE6005 | GEO
Project description:In the intestine, B. cereus comes in contact with the epithelial mucus layer. To investigate the overall response to that contact, total transcriptome analyses were performed using porcine gastric mucin (PGM), which is a commonly applied model for mucus interactions. Differential regulation of genes encoding enterotoxins and further virulence factors was of special interest.
2019-03-25 | GSE127189 | GEO