A microscopic approach to visualize assumed beneficial properties of Mars Global Simulant 1S on the desiccation tolerance of exemplary microorganisms

Abstract

Astrobiological research is focused on past and present life in the universe and the habitability of other celestial bodies. To address questions within this topic long-term space exposure experiments are a useful method of choice. These experiments require microorganisms which are known to withstand harsh conditions. Such organisms can be found in extreme and even extra-terrestrial analogue environments on Earth. One example are desiccation tolerant organisms which are of high interest for scientists in the field of astrobiology as it is of interest to investigate if these organisms might even be more tolerant, to desiccation or other Mars relevant stress factors, in simulated Martian conditions. The addition of Martian global simulant 1S (MGS-1S) has shown to be a promising candidate to improve the desiccation tolerance of several organisms. However, the mechanism behind this is still not clear. Here we try to show whether or not this mechanism is mechanical or chemical, by observing cultures grown in different conditions microscopically. However, this study was not able to clarify the reason behind the altered desiccation tolerance, as microscopy pictures do no show differences between cultures grown with and without regolith. Nevertheless, it could be shown that the addition of MGS-1S does impact the desiccation tolerance of some microorganism whereas others do not benefit from the addition. This study shows that MGS-1S is indeed a promising tool regarding the alteration of desiccation tolerance but the underlying mechanism still needs to be investigated.