Riekeles Max, Santos Berke, Youssef Sherif Al-Morssy, Schulze-Makuch Dirk
Astrobiology Group, Center of Astronomy and Astrophysics, Technical University Berlin, 10623 Berlin, Germany.
Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
Life (Basel). 2024 Nov 21;14(12):1526. doi: 10.3390/life14121526.
This study investigates the effects of three Martian-relevant salts-sodium chlorate, sodium perchlorate, and sodium chloride-on the viability and motility of , a model organism for understanding microbial responses to environmental stress. These salts are abundant on Mars and play a crucial role in forming brines, one of the few sources of stable liquid water on the planet. We analyze the survivability under different salt concentrations using colony plating. Additionally, we perform a semi-automated motility analysis, analyzing microbial speeds and motility patterns. Our results show that sodium perchlorate is the most toxic, followed by sodium chlorate, with sodium chloride being the least harmful. Both survivability and motility are affected by salt concentration and exposure time. Notably, we observe a short-lived increase in motility at certain concentrations, particularly under sodium chlorate and sodium perchlorate stress, despite rapid declines in cell viability, suggesting a stress response mechanism. Given that motility might enhance an organism's ability to navigate harsh and variable environments, it holds promise as a key biosignature in the search for life on Mars.
本研究调查了三种与火星相关的盐——氯酸钠、高氯酸钠和氯化钠——对嗜盐栖热袍菌（一种用于理解微生物对环境应激反应的模式生物）的活力和运动性的影响。这些盐在火星上含量丰富，在形成卤水（这是该星球上为数不多的稳定液态水源之一）过程中起着关键作用。我们使用菌落平板计数法分析不同盐浓度下的存活率。此外，我们进行了半自动运动性分析，分析微生物的速度和运动模式。我们的结果表明，高氯酸钠毒性最大，其次是氯酸钠，而氯化钠危害最小。存活率和运动性均受盐浓度和暴露时间的影响。值得注意的是，尽管细胞活力迅速下降，但我们观察到在某些浓度下运动性会出现短暂增加，特别是在氯酸钠和高氯酸钠胁迫下，这表明存在一种应激反应机制。鉴于运动性可能增强生物体在恶劣多变环境中导航的能力，它有望成为在火星上寻找生命的关键生物特征。
