Abstract EANA2026-20

Homochirality is a defining feature of life on Earth and one of the focuses in the search for biosignatures beyond our planet. However, extraterrestrial conditions may alter these traces of life. On Mars, wind-driven saltation abrades sand grains by repeated low-velocity impacts, exposing organics to erosion. Here, we present a study designed to evaluate the impact of simulated saltation on cells, biomolecules and their chirality to understand the influence of mechanical processes on biosignature preservation. 

Basalt and plagioclase sand was coated with Deinococcus Radiodurans cells and tumbled under simulated Martian conditions for up to a week. Cell survival was evaluated by CFU counts and flow cytometry. DNA was quantified using fluorescence and qPCR analyses, and fragmentation was evaluated by gel electrophoresis. Protein content was analyzed by fluorescence and SDS-PAGE. Chiral analyses by comprehensive two-dimensional gas chromatography will be conducted to test if abrasion may induce racemization in amino acids, the building blocks of proteins.

A strong decrease in cell and DNA abundance was observed early in the experiment, with the steepest decline occurring during the first two days, followed by a slower decline. In contrast, protein quantity was less affected, although longer tumbling times were associated with the appearance of smaller molecular fragments. These results indicate that saltation is strongly abrasive to cells and biomolecules and may therefore compromise biosignature preservation. Enantiomeric excesses at each step of the experiment will assess the preservation of chirality and confirm if homochirality could also be compromised.