Assessing cell survival and biosignature preservation of the extremely thermoacidophilic archaeon Acidianus manzaensis after exposure to Mars-like conditions

Considering the harsh surface conditions on Mars, terrestrial organisms that can survive and remain detectable after exposure to similar conditions provide invaluable models for guiding current and future search-for-life missions. To this end, we evaluated the extremophilic archaeon Acidianus manzaensis grown on ESA01-E Mars analog material as a model organism. We exposed cell-mineral mixtures to one month of desiccation and two weeks of Mars-like conditions in a Mars simulation chamber to evaluate the potential for cell survival after exposure to these conditions. In the search for reliable biomarkers in other planetary environments, such as Mars, molecules that are stable over geological timescales while preserving information indicative of their potential biological origin are crucial. Thiophene-bearing quinones fulfill these requirements, and thiophenes, which are their basic moieties, have been discovered on Mars. Therefore, we analyzed the thiophene-bearing quinone composition of A. manzaensis using mass spectrometry-based metabolomics and discussed potential molecular alterations. Successful re-cultivation after one month of desiccation and two weeks of exposure to Mars-like conditions proved the durability of the organism and its capability for cell recovery after exposure to extreme conditions, paving the way for further investigation.