Bacillus cereus spore and cell proteome dynamics

Bacterial spores are resistant structures capable of survival under unfavorable conditions. To get a deeper understanding of the spores’ germination process and provide fundamental knowledge for the strategies in the food industry, proteomics experiments are designed and conducted on B. cereus spores in this thesis. The protein composition of the spore inner membrane is first studied and compared with vegetative cell membrane proteome, the results of which demonstrated the differences in membrane proteome composition and the specifically required proteins in the inner membrane of B. cereus dormant spores to survive adverse conditions. Further, the protein dynamics during germination and outgrowth of spores coupled with co-expression network analysis were analyzed. This study showed the protein dynamics during B. cereus spore germination and outgrowth for the first time and provided a global view for a deeper understanding of the organization of proteins during spore revival. Additionally, to study the effects of intracellular perturbations on the spore proteome of B. cereus we examined and compared the spore proteome of the GR fusion protein mutants with wild type and demonstrated the extent that plasmid based genetic tools influence the composition of spores. Finally, a successful application of the single-pot, and solid phase-enhanced sample-preparation (SP3) method on spore and vegetative samples was described in the thesis. The results showed that the SP3 protein cleanup method can be used in spore related researches and be a substitute of “one-pot” method.