Abstract EANA2024-31

The biophysical limits to life in multi-extreme environments are notoriously hard to explore due to the lack of instrumentation that can tolerate such harsh conditions. However, high-pressure differential scanning calorimetry (HPDSC) enables the measurement of thermal events such intracellular vitrification and proteome melting across temperature, pressure, and ionic compositions. Here I show that pressures of 1 kbar can depress the onset of intracellular vitrification of Bacillus subtilis  by ~8 °C, from -23 °C to -31 °C. These results suggest that the high pressures of the Martian and icy moon subsurface environments may enable cells to maintain their liquid state at even lower temperatures if combined with salts which are known to depress ice formation and intracellular vitrification. Additionally, it is shown how the proteome melting of Bacillus subtilis is affected by high pressures and perchlorate salts through HPDSC. These results demonstrate that HPDSC can used as a tool to measure the biophysical limits to life in multi-extreme conditions.