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High Tolerance of Hydrogenothermus marinus to Sodium Perchlorate
Kristina Beblo-Vranesevic1, Harald Huber2, Petra Rettberg1
1Radiation Biology Division, Institute of Aerospace Medicine, German Aerospace Center (DLR e.V.)Cologne, Germany.
Abstract:
On Mars, significant amounts (0.4-0.6%) of perchlorate ions were detected in dry soil by the Phoenix Wet Chemistry Laboratory and later confirmed with the Mars Science Laboratory. Therefore, the ability of Hydrogenothermus marinus, a desiccation tolerant bacterium, to survive and grow in the presence of perchlorates was determined. Results indicated that H. marinus was able to tolerate concentrations of sodium perchlorate up to 200 mM ( 1.6%) during cultivation without any changes in its growth pattern. After the addition of up to 440 mM ( 3.7%) sodium perchlorate, H. marinus showed significant changes in cell morphology; from single motile short rods to long cell chains up to 80 cells. Furthermore, it was shown that the known desiccation tolerance of H. marinus is highly influenced by a pre-treatment with different perchlorates; additive effects of desiccation and perchlorate treatments are visible in a reduced survival rate. These data demonstrate that thermophiles, especially H. marinus, have so far, unknown high tolerances against cell damaging treatments and may serve as model organisms for future space experiments.
Insights
The bacterium Hydrogenothermus marinus tolerates high perchlorate concentrations found on Mars. Pre-treatment with perchlorates affects its desiccation tolerance, suggesting potential for space experiments.
Area of Science:
- Astrobiology
- Extremophile Biology
- Microbial Physiology
Background:
- Perchlorate ions are present in Martian soil at significant concentrations (0.4-0.6%).
- Desiccation-tolerant microorganisms may hold keys to understanding life's adaptability in extreme environments.
Purpose of the Study:
- To determine the survival and growth capabilities of Hydrogenothermus marinus in the presence of perchlorates.
- To investigate the influence of perchlorates on the desiccation tolerance of H. marinus.
Main Methods:
- Cultivation of H. marinus with varying concentrations of sodium perchlorate.
- Microscopic observation of cell morphology changes.
- Assessment of survival rates under combined desiccation and perchlorate stress.
Main Results:
- H. marinus tolerated sodium perchlorate up to 200 mM (1.6%) without altered growth.
- Higher perchlorate concentrations (up to 440 mM or 3.7%) induced morphological changes, forming long cell chains.
- Perchlorate pre-treatment negatively impacted desiccation tolerance, showing additive stress effects.
Conclusions:
- H. marinus exhibits remarkable tolerance to perchlorate, a key Martian soil component.
- Perchlorate exposure modifies H. marinus cell structure and affects its response to desiccation.
- Thermophiles like H. marinus serve as valuable models for astrobiological research and space exploration.
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