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Astrobiology

Astrobiology is the interdisciplinary study of life in the universe, focused primarily on investigations to the origin, distribution and evolution of life. One major astrobiological research topic encompasses the question of what kind of environments can life tolerate. In the last decades the number of organisms discovered at locations, which would have been classified still recently as 'life-hostile', has increased immensely. Examples of such extremophilic terrestrial organisms are microorganisms from hot springs, hydrothermal vents, deserts, permafrost, salt crystals, and very acid or basic water. The increasing knowledge of the microbial adaptability and its fundamental molecular mechanisms enable the estimation of their hypothetical viability on other planets in our solar system, e.g. on Mars. The ability of life to move beyond Earth will depend upon the potential for microorganisms to utilize resources, and to adapt and evolve in extraterrestrial environments. Viable microorganisms might be transported by natural events such as impacts or by robotic spacecraft, but they most certainly will accompany human missions. Life forms will be challenged by extremes in temperature, pressure, radiation and the availability of nutrients. Studies of adaptation and survival will indicate not only whether microbial life can expand its evolutionary trajectories beyond Earth but also how it can play key supporting roles in human exploration.

The Lehrstuhl für Mikrobiologie and the Archaea Centre of the University of Regensburg have a long-lasting expertise in isolating, growing and characterizing extremophilic Bacteria and Archaea. These microorganisms are able to thrive under physicochemical conditions which are extreme and hostile for most life forms known on this planet. They are a rich resource of model organisms also for studying the effect of conditions in outer space or on other planets of our solar system, concerning radiation of various kinds (UV, ionizing), and extreme draught, i.e. low water pressure. While the Archaea Centre in Regensburg has tested the microorganisms under several kinds of extreme conditions, further astrobiological experiments cannot be performed in Regensburg.

The Research School provides the unique opportunity to join the biological resources of the Regensburg Archaea Centre with the equipment and expertise of the DLR research group 'Photo- and Exobiology', where laboratory and space experiments concerning research on viability and adaptability to space as well as to simulated Martian conditions are accomplished. The molecular and cellular mechanisms for the adaptation to extreme environmental conditions and the capability to repair different kinds of damages will be investigated in several microbial model organisms. The response of cells exposed to vacuum and ionizing radiation will be tested, and the cellular content of small and large molecules which are known to help microorganisms to sustain extreme conditions, like compatible solutes and protein complexes called chaperonins will be analyzed. Both molecules have been described to accumulate to great extent in the cytosol upon exposure to stress conditions.

The results of these ongoing investigations are also important for the development of ESA planetary protection guidelines for the future exploration of our solar system.