Project description:Bacillus pumilus SAFR-032 was originally isolated from the Jet Propulsion Lab Spacecraft Assembly Facility and thoroughly characterized for its enhanced resistance to UV irradiation and oxidative stress. This unusual resistance of SAFR-032 is of particular concern in the context of planetary protection and calls for development of novel disinfection techniques to prevent extraterrestrial contamination. Previously, spores of SAFR-032 were exposed for 18 months to a variety of space conditions on board the International Space Station to investigate its resistance to Mars conditions and space travel. Here, proteomic characterization of vegetative SAFR-032 cells from space-surviving spores is presented in comparison to a ground control. Vegetative cells of the first passage were processed and subjected to quantitative proteomics using tandem mass tags. Approximately 60% of all proteins encoded by SAFR-032 were identified and 301 proteins were differentially expressed among the strains. The functional analysis of differentially expressed proteins revealed the downregulation of proteins related to carbohydrate transport/metabolism and energy production/conversion, which was validated by enzymatic assays. The same space-surviving strains showed upregulation of proteins related to competitive growth and stress response. Observed protein profiles provide insights into the possible molecular mechanisms of B. pumilus SAFR-032 to adapt and resist extreme extraterrestrial environments.
Project description:Reactive oxygen species such as hydrogen peroxide occur in all aerobically living organisms. Oxidative stress during fermentation can impair the fitness of the production host and the quality of the product. B. pumilus has been described as highly resistant to hydrogen peroxide. The response of exponentially growing B. pumilus cells to hydrogen peroxide was studied.
Project description:The proteome of Bacillus pumilus spores was established by shotgun proteomics to better characterize this biological material used as indicator to assess the effectiveness of decontamination procedures.
