State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2023 Aug 15;886:163952. doi: 10.1016/j.scitotenv.2023.163952. Epub 2023 May 8.
Earth's near space is an extreme atmosphere environment with high levels of radiation, low atmospheric pressure and dramatic temperature fluctuations. The region is above the flight altitude of aircraft but below the orbit of satellites, which has special and Mars-like conditions for investigating the survival and evolution of life. Technical limitations including flight devices, payloads and technologies/methodologies hinder microbiological research in near space. In this study, we investigated microbial survival and adaptive strategies in near space using a scientific balloon fight mission and multi-omics analyses. Methods for sample preparation, storage, protector and vessel were optimized to prepare the exposed microbial samples. After 3 h 17 min of exposure at a float altitude of ~32 km, only Bacillus strains were alive with survival efficiencies of 0-10. Diverse mutants with significantly altered metabolites were generated, firstly proving that Earth's near space could be used as a new powerful microbial breeding platform. Multi-omics analyses of mutants revealed cascade changes at the genome, transcriptome and proteome levels. In response to environmental stresses, two mutants had similar proteome changes caused by different genomic mutations and mRNA expression levels. Metabolic network analysis combined with proteins' expression levels revealed that metabolic fluxes of EMP, PPP and purine synthesis-related pathways were significantly altered to increase/decrease inosine production. Further analysis showed that proteins related to translation, molecular chaperones, cell wall/membrane, sporulation, DNA replication/repair and anti-oxidation were significantly upregulated, enabling cells to efficiently repair DNA/protein damages and improve viability against environmental stress. Overall, these results revealed genetic and metabolic responses of Bacillus to the harsh conditions in near space, providing a research basis for bacterial adaptive mechanisms in extreme environments.
地球近地空间是一种极端的大气环境，具有高水平的辐射、低气压和剧烈的温度波动。该区域位于飞机飞行高度以上，但低于卫星轨道以下，对于研究生命的生存和演化具有特殊的、类似火星的条件。技术限制，包括飞行设备、有效载荷和技术/方法，阻碍了近地空间的微生物研究。在这项研究中，我们使用科学气球飞行任务和多组学分析来研究近地空间中的微生物生存和适应策略。优化了样品制备、储存、保护和容器的方法，以准备暴露的微生物样品。在约 32 公里的漂浮高度暴露 3 小时 17 分钟后，只有芽孢杆菌菌株存活，存活效率为 0-10。生成了具有明显改变代谢物的多种突变体，首先证明地球近地空间可用作新的强大微生物繁殖平台。突变体的多组学分析揭示了基因组、转录组和蛋白质组水平的级联变化。为了应对环境压力，两个突变体具有相似的蛋白质组变化，这是由不同的基因组突变和 mRNA 表达水平引起的。代谢网络分析结合蛋白质表达水平表明，EMP、PPP 和嘌呤合成相关途径的代谢通量显著改变，以增加/减少肌苷的产生。进一步分析表明，与翻译、分子伴侣、细胞壁/膜、孢子形成、DNA 复制/修复和抗氧化相关的蛋白质显著上调，使细胞能够有效地修复 DNA/蛋白质损伤，提高对环境压力的生存能力。总的来说，这些结果揭示了芽孢杆菌对近地空间恶劣条件的遗传和代谢反应，为细菌在极端环境中的适应机制提供了研究基础。
