Matthews Adrianna, Lima-Zaloumis Jonathan, Debes Ii R Vincent, Boyer Grayson, Trembath-Reichert Elizabeth
School of Earth and Space Exploration, Arizona State University, Tempe, Arizona, USA.
Astrobiology. 2023 Apr;23(4):446-459. doi: 10.1089/ast.2022.0100. Epub 2023 Jan 31.
Due to their ability to withstand "extreme" conditions, Earth's extremophilic organisms can constrain habitability windows for other planetary systems. However, there are many other considerations to microbial growth requirements beyond environmental extremes, such as nutrient availability. Here, we conduct a literature review of the most extremotolerant extremophiles in culture, since working with cultured organisms allows environmental and nutrient variables to be constrained with a high level of specificity. We generated a database that includes the isolation environment, carbon source(s) used, and growth preferences across temperature, pressure, salinity, and pH extremes. We found that the "most extreme" conditions were primarily sustained by heterotrophs, except for hyperthermophiles. These results highlight the importance of considering organic carbon availability when using extremophiles for habitability constraints. We also interrogated polyextreme potential across temperature, pressure, salinity, and pH conditions. Our findings suggest that the investigation of growth tolerance rather than growth optimum may reveal wider habitability parameters. Overall, these results highlight the potential polyextremes, environments, nutrient requirements, and additional analyses that could improve the application of cultured investigations to astrobiology questions.
由于其耐受“极端”条件的能力，地球上的极端微生物会限制其他行星系统的宜居窗口。然而，除了极端环境之外，微生物生长需求还有许多其他需要考虑的因素，比如养分的可利用性。在此，我们对培养的最耐极端环境的极端微生物进行了文献综述，因为研究培养的生物体能够高度特异性地限制环境和养分变量。我们建立了一个数据库，其中包括分离环境、所使用的碳源以及在温度、压力、盐度和pH值极端条件下的生长偏好。我们发现，除了嗜热菌外，“最极端”的条件主要由异养生物维持。这些结果凸显了在利用极端微生物来限制宜居性时考虑有机碳可利用性的重要性。我们还探究了在温度、压力、盐度和pH值条件下的多极端潜力。我们的研究结果表明，对生长耐受性而非生长最适条件的研究可能会揭示更广泛的宜居性参数。总体而言，这些结果凸显了潜在的多极端情况、环境、养分需求以及其他分析，这些分析能够改进将培养研究应用于天体生物学问题的情况。
