Investigating changes in thiophene-bearing quinones of the archaeon Acidianus manzaensis after exposure to Mars-like conditions

In the search for reliable biomarkers in other planetary environments such as Mars, molecules that are stable over geological timescales, while preserving indicative information about their potential biological origin, are crucially needed. Thiophene-bearing quinones fulfill these requirements, and thiophenes, which are their basic moieties, have been found on Mars. However, thiophenes can be produced abiotically and have been found in meteorites. Furthermore, the Martian environment may alter their molecular structure over time. To evaluate whether there could be a distinction between biotically and abiotically produced thiophenes, considering the harsh environmental conditions on Mars, we cultivated the extremophilic archaeon Acidianus manzaensis on ESA01-E Mars analog material. We then exposed the cell-mineral samples to one month of desiccation and Mars-like conditions in a Mars simulation chamber to analyze changes in the composition of thiophene-bearing quinones using mass spectrometry-based metabolomics, and evaluated the potential for cell recovery after exposure.