The extraordinarily resistant bacterium Deinococcus radiodurans withstands harsh environmental conditions present in outer space. Deinococcus radiodurans was exposed for 1 year outside the International Space Station within Tanpopo orbital mission to investigate microbial survival and space travel. In addition, a ground-based simulation experiment with conditions, mirroring those from low Earth orbit, was performed. We monitored Deinococcus radiodurans cells during early stage of recovery after low Earth orbit exposure using electron microscopy tools. Furthermore, proteomic, transcriptomic and metabolomic analyses were performed to identify molecular mechanisms responsible for the survival of Deinococcus radiodurans in low Earth orbit. D. radiodurans cells exposed to low Earth orbit conditions do not exhibit any morphological damage. However, an accumulation of numerous outer-membrane-associated vesicles was observed. On levels of proteins and transcripts, a multi-faceted response was detected to alleviate cell stress. The UvrABC endonuclease excision repair mechanism was triggered to cope with DNA damage. Defense against reactive oxygen species is mirrored by the increased abundance of catalases and is accompanied by the increased abundance of putrescine, which works as reactive oxygen species scavenging molecule. In addition, several proteins and mRNAs, responsible for regulatory and transporting functions showed increased abundances. The decrease in primary metabolites indicates alternations in the energy status, which is needed to repair damaged molecules. Low Earth orbit induced molecular rearrangements trigger multiple components of metabolic stress response and regulatory networks in exposed microbial cells. Presented results show that the non-sporulating bacterium Deinococcus radiodurans survived long-term low Earth orbit exposure if wavelength below 200 nm are not present, which mirrors the UV spectrum of Mars, where CO2 effectively provides a shield below 190 nm. These results should be considered in the context of planetary protection concerns and the development of new sterilization techniques for future space missions.

中文翻译：

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在Tanpopo任务中在国际空间站外暴露1年后，放射性杜鹃球菌的分子库

抵抗力极强的Deinococcus radiodurans细菌能承受外太空存在的恶劣环境条件。在坦波波（Tanpopo）轨道飞行任务中，放线菌（Deinococcus radiodurans）被暴露在国际空间站外一年，以调查微生物的存活和太空旅行。此外，还进行了基于地面条件的模拟实验，模拟了来自低地球轨道的情况。在低地球轨道暴露后，我们使用电子显微镜工具在恢复的早期监测了Deinococcus radiodurans细胞。此外，进行了蛋白质组学，转录组学和代谢组学分析，以确定负责低地球轨道放射性杜氏球菌生存的分子机制。暴露于低地球轨道条件下的D. radiodurans细胞不表现出任何形态学损害。然而，观察到许多外膜相关囊泡的积累。在蛋白质和转录本的水平上，检测到多方面的反应以减轻细胞应激。触发了UvrABC核酸内切酶切除修复机制以应对DNA损伤。过氧化氢酶丰度的增加反映了对活性氧种类的防御，并伴随着腐胺的增加，腐胺作为活性氧种类的清除分子。此外，负责调节和转运功能的几种蛋白质和mRNA显示出增加的丰度。初级代谢产物的减少表明能量状态的改变，这是修复受损分子所必需的。低地球轨道诱导的分子重排触发暴露的微生物细胞中代谢应激反应和调节网络的多个成分。提出的结果表明，如果不存在低于200 nm的波长，则非形成芽孢的Deinococcus radiodurans细菌可以长期长期暴露在低地球轨道下，这反映了火星的UV光谱，其中CO2有效地提供了190 nm以下的屏蔽。这些结果应在对行星保护的关注以及针对未来太空飞行的新灭菌技术的发展中加以考虑。CO2有效地提供了190 nm以下的屏蔽。这些结果应在对行星保护的关注以及针对未来太空飞行的新灭菌技术的发展中加以考虑。CO2有效地提供了190 nm以下的屏蔽。这些结果应在对行星保护的关注以及针对未来太空飞行的新灭菌技术的发展中加以考虑。