Project description:Transcriptome analyses after the transfer of pCER270-spec megaplasmid in B. cereus F4810-72 (previously cured for its plasmid), B. thuringiensis HD73, and B. weihenstephanensis KBAB6 strains. We determined differentially expressed genes in pCER270+ strains in comparison with pCER270- strains.
Project description:Pathogenic species belonging to Bacillus cereus sensu lato group possess a high evolutionary advantage in the environment and in food matrices thanks to their capacity to survive as silent spores to harsh environmental insults and grow at relatively low temperatures. Ready to re-heat products are at severe risk for contamination by members of Bacillus cereus s.l. group if not stored at proper conditions. In this work, the goal was to assess, by means of a genome-wide transcriptional assay, the isolated strain Bacillus cereus UC10070 gene expression behind the process of spore germination and consequent outgrowth in an artificially contaminated vegetable-based food model. A vegetable food model subjected to a heat treatment was determined to present favourable conditions for spores germination. Microscopic analyses together with OD measurements were applied to select the key steps of B. cereus cell cycle to be used for the microarray analysis. Using this approach we found a total of 1,646 probe sets differentially expressed and modulated during the entire B. cereus life cycle in the vegetable foodstuff.
Project description:Pathogenic species belonging to Bacillus cereus sensu lato group possess a high evolutionary advantage in the environment and in food matrices thanks to their capacity to survive as silent spores to harsh environmental insults and grow at relatively low temperatures. Ready to re-heat products are at severe risk for contamination by members of Bacillus cereus s.l. group if not stored at proper conditions. In this work, the goal was to assess, by means of a genome-wide transcriptional assay, the isolated strain Bacillus cereus UC10070 gene expression behind the process of spore germination and consequent outgrowth in an artificially contaminated vegetable-based food model. A vegetable food model subjected to a heat treatment was determined to present favourable conditions for spores germination. Microscopic analyses together with OD measurements were applied to select the key steps of B. cereus cell cycle to be used for the microarray analysis. Using this approach we found a total of 1,646 probe sets differentially expressed and modulated during the entire B. cereus life cycle in the vegetable foodstuff. RNA was isolated from the dormant spores (DS), germinating spores at 40 minutes (GSP), early-log phase at 2h (C2h) and late log phase cells at 12 hours (C12h) after thermal treatment of B. cereus UC10070 previously isolated froma biofilm on a spoiled vegetable-based puree. There were 3 biological replicates (independent cultures) for each condition. Complete genome sequence of B. thuringiensis sv konkukian str. 97-27 (NCBI Reference Sequence: NC_005957.1) was chosen for its high homology with B. cereus s.l. UC10070, to design probes corresponding to 5,197 genes spotted in duplicates onto ElectraSenseH 12K microarrays chip.
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.