BOSS CYANO EXPERIMENT ON THE EXPOSE-R2 SPACE MISSION: ENHANCED SURVIVAL OFudCHROOCOCCIDIOPSIS BIOFILMS TO SPACE AND SIMULATED MARS CONDITIONSudCOMPARED TO PLANKTONIC COUNTERPARTS

摘要

The Biofilm Organisms Surfing Space (BOSS) experiment is part of the EXPOSE-R2 space mission.udIn one part of the BOSS experiment three Chroococcidiopsis desert stains (CCMEE 057, CCMEE 029udand CCMEE 064), were exposed to Low Earth Orbit (LEO) in the dried state either as biofilms orudmultilayered planktonic samples. Cells were exposed for 16 months to space and Mars-like conditionsudoutside the International Space Station. Exposure parameters included temperature variations, ionizingudradiation, vacuum or simulated Martian atmosphere and pressure, and Mars-like solar UV irradiation. Inudparallel to exposure in LEO, replicates of the experiment were performed on the ground: Some were keptudin the dark under ambient conditions, while others were exposed to stressors (extreme temperature cycles,udMars-simulated atmosphere or vacuum, and UV udux) mimicking those undergone during the EXPOSE-R2udspace mission, based on data recorded in-udight. Cyanobacteria were analyzed post-udight using confocaludmicroscopy, PCR-based assays and colony forming ability tests. Results are consistent with previousudground-based simulations of the mission1,2 and demonstrate an overall higher resistance of biofilms whenudcompared to planktonic as suggested by their increased viability and lower amounts of DNA damage.ud1. Baqué, M., Scalzi, G., Rabbow, E., Rettberg, P. Billi, D. Biofilm and Planktonic LifestylesudDifferently Support the Resistance of the Desert Cyanobacterium Chroococcidiopsis Under Space andudMartian Simulations. Orig. life Evol. Biosph. 43, 377-389 (2013).ud2. Baqué, M., de Vera, J.-P., Rettberg, P. Billi, D. The BOSS and BIOMEX space experiments on theudEXPOSE-R2 mission: Endurance of the desert cyanobacterium Chroococcidiopsis under simulated spaceudvacuum, Martian atmosphere, UVC radiation and temperature extremes. Acta Astronaut. 91, 180-186ud(2013).