Detection of dsrAB operon expression in Desulfotalea psychrophila cells subjected to simulated Martian conditions of temperature and regolith's sulphate minerals composition
by Mosquera, Sergio; Ivey, Mack; Chevrier, Vincent F.
Discoveries of transient liquid water in the Martian polar caps and the presence of liquid lakes and subsurface oceans in icy satellites have increased the interest of scientists in the capabilities of terrestrial extremophiles to grow and remain metabolically active in these extreme environments. The principal goal of this research is to understand the metabolic capacity of the anaerobic psychrophile, Desulfotalea psychrophila, cultured at subfreezing temperatures in media containing various concentrations of sulfate minerals. In this regard, our experiments focused on the detection of D. psychrophila survival and active metabolism, employing a biochamber that can recreate Martian temperatures Using standard bacteriol. methods for determining growth, combined with mol. and enzymic determination of sulfate reduction, we have found that D. psychrophila is capable to carry out biol. processes at temperatures down to -5°C, at concentrations that range from 0.35 to 18 wt% of MgSO4, 0.1 wt% of CaSO4 and 10 to 14 wt% of FeSO4 in which the highest sulfate concentration gradually returned the biosynthetic rate to basal limits, and the lowest temperature decreased bacterial cell division. These chem. salts, whose ions are classified as chaotropes, are known to act by maintaining water mols. in liquid state at subfreezing temperatures and by altering the stability of cellular components. This 'chaotropic effect' could potentially benefit the microbial metabolic activity up to a concentration in which cellular viability is jeopardized. Consequently, our hypothesis is directed towards the detection of metabolic activity as an indirect measurement of the potential influence of these ions in the flexibility/functionality of biol. structures that at cold temperatures are highly rigid, compact and partially/non-functional due to water freezing. Studies of this type of microorganism are critical considering the possibility of survival and colonization of psychrophilic sulfate reducers in other planets and icy satellites.
- Journal
- International Journal of Astrobiology
- Volume
- 22
- Issue
- 6
- Year
- 2023
- Start Page
- 641-662
- URL
- https://dx.doi.org/10.1017/s1473550423000198
- ISBN/ISSN
- 1473-5504; 1475-3006
- DOI
- 10.1017/s1473550423000198