Resistance of the anhydrobiotic eutardigrade Paramacrobiotus richtersi to space flight (LIFE–TARSE mission on FOTON-M3). ,

The project “TArdigrade Resistance to Space Effects (TARSE)” analyzed the effects of space environment stresses on the eutardigrade Paramacrobiotus richtersi allowing, for the first time, a comparison between hydrated and desiccated animals. TARSE experiments were part of the mission LIFE on FOTON-M3 that flew at an altitude between 250-290 km for 12 days in September 2007. In this paper, data on survival rate, Hsps expression (70 kDa and 90 kDa) and genomic DNA integrity (double strand breaks) of flown desiccated animals, and from specimens in ground control experiments are presented. For the flown experiments, microcosms of dry leaf litter collected in the field containing naturally desiccated specimens and square papers containing specimens desiccated under controlled conditions were used. After the space flight, desiccated animals had high survival rates (from 79% to 95%) showing a similar survival rate to that observed in ground controls. No visible damages to double strand genomic DNA were observed in all desiccated samples, while spaceflight induced the Hsps expression (Hsp70 and Hsp90) compared to ground controls. These data combined with earlier published results on hydrated specimens of P. richtersi indicate that tardigrades have the ability to tolerate for a short period of time several extreme stresses typical of the extraterrestrial environment.