UV resistance of the halophilic Archeon Natrinema hispanica

The search for past or existing life and for its traces on Mars is one main topic in Astrobiology. The presence of liquid water is essential for the emergence of life, as we know it, therefore if life existed on Mars, it should have developed in the earlier periods of its life. Data from various mission suggested the presence of liquid water on Mars, that was lost maybe by evaporation when the planet lost its atmosphere. In this scenario, water’s evaporation could have caused the concentration of the dissolved minerals and therefore the formation of brine pockets and evaporites. Such an environment would have selected organisms able to survive in a saline or hypersaline environment. Therefore, if life existed on Mars, a likely Martian biota would have been made of halophilic organisms. Life in saline and hypersaline environments on Earth is extremely diverse, including either microbial species or few macroorganisms, that are adapted to salt saturation concentrations, i.e. halophiles. In this poster we reported preliminary experiments assessing the resistance to Mars brine simulation, of the halophilic Arcahea Natrinema hispanica, an extremely halophilic archaeon from Fuente de Piedra, southern Spain, selected from the bacterial collection of the Institute of Biomolecular Chemistry (CE-ICB), [PNRR European Commission – NextGenerationEU, Project “SUS-MIRRI" n. IR0000005]. Natrinema hispanica, that has been the object of previous studies in which its resistance to several stressors mimicking the space environment was investigated. Mars simulation was carried out by irradiating with increasing UVB and UVC doses (up to 70000 J/m2), samples of Natrinema hispanica desiccated from its hypersaline medium containing KCl 2 g/L, sodium Citrate 3 g/L, MgSO4 20 g/L and NaCl 200g/L. Samples obtained at different conditions of irradiation were then characterized through NMR-based metabolic profiling.