Common Yeast Survives Martian Conditions

Any past or future life on Mars must contend with challenging conditions, including, but not limited to, shock waves from meteorite impacts and soil perchlorates—highly oxidizing salts that destabilize hydrogen bonds and hydrophobic interactions.

In a study described in an article published V PNAS NexusPurushart I. Rajyaguru of the Indian Institute of Sciences, Bangalore, and colleagues subjected yeast Saccharomyces cerevisiae exposure to shock waves and perchlorates.

The authors chose yeast in part because it had already been studied in space. Under stress, yeast and many other organisms form ribonucleoprotein (RNP) condensates, structures made of RNA and proteins that protect the RNA and influence the fate of the mRNA. After the stressor disappears, RNP condensates, including their subtypes “stress granules” and “P-bodies,” disintegrate.

The authors simulated Martian shock waves at the Physics Research Laboratory in Ahmedabad, India.

Yeast exposed to shock waves with an intensity of Mach 5.6 (max – ratio of the speed of an object to the speed of sound in specific environment)survived by slowing their growth, as did yeast exposed to 100 millimoles of sodium perchlorate NaClO₂ — concentrations similar to those present in Martian soil. The yeast cells also survived the combined stress of both the shock waves and perchlorate. In both cases, the yeast formed RNP condensates.

Mutants incapable of assembling RNP condensates did not tolerate Martian conditions well. Transcriptomic analysis revealed specific RNA transcripts disrupted by Martian-like conditions.

The results demonstrate the importance of yeast and RNP condensates in understanding the impact of Martian conditions on life, the authors said.

Subscribe and read “Science” in Telegram