Bacillus subtilis spores PROTECT experiment Space-exposed and Mars-exposed vs. Earth-control

Thus it is important to understand their global responses to long-term exposure to space or Mars environments. As part of the PROTECT experiment spores of B. subtilis 168 were exposed to real space conditions and to simulated martian conditions for 559 days in low Earth orbit mounted on the EXPOSE-E exposure platform outside the European Columbus module on the International Space Station.

Upon return spores were germinated total RNA extracted and fluorescently labeled and used to probe a custom Bacillus subtilis microarray to identify genes preferentially activated or repressed relative to ground control spores. Increased transcript levels were detected for a number of stress-related regulons responding to DNA damage (SOS response SP-beta prophage induction) protein damage (CtsR/Clp system) oxidative stress (PerR regulon) and cell envelope stress (SigV regulon).