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.
Project description:The study aims to identify the metabolic differences between two promising fast-growing, non-model cyanobacterial strains, S. elongatus PCC 11801 and PCC 11802. To this end, dynamic 13C-labeling experiments were carried out in the two cyanobacterial strains grown in shake flasks at a similar light intensity of approx. 300-350 µmole photons.m-2. s-1. The samples for metabolomics analysis were collected during the exponential growth phase at an optical cell density of 0.5-0.6. The detailed protocol for experiment can be found in the protocol file.
Project description:The study aims to identify the metabolic differences between two promising fast-growing, non-model cyanobacterial strains, S. elongatus PCC 11801 and PCC 11802. To this end, experiments were carried out to measure metabolite levels in the two cyanobacterial strains grown in shake flasks at a similar light intensity of approx. 300-350 µmole photons.m-2. s-1. The samples for metabolomics analysis were collected during the exponential growth phase at an optical cell density of 0.5-0.6. Isotopic ratio method was utilized to compare the metabolite levels and delineate the differences in their metabolic pathways.
Project description:We installed and optimized a genetic tool that allows control over protein stability in a model cyanobacterium. This tool has potential uses for the fundamental study of cyanobacterial genes, and may be useful for the design of more sophisticated, bioindustrial cyanobacterial strains.