Abstract：
Spore-forming bacteria have a unique resistance to negative environmental conditions, including aggressive space factors, and are an excellent model for studying adaptation mechanisms and survival strategies at the molecular level. The study analyzed the genome of Bacillus velezensis, which remained viable after a 2-year exposure in outer space on the outer surface of the ISS as part of the Test space experiment. A comparative analysis of the draft genomes of the exhibit strain and the ground control did not reveal significant changes; the average nucleotide identity was 99.98%, which indicates the ability of microorganisms to maintain genome stability in space conditions, due to both increased stress resistance of bacterial spores and efficient operation of the system of repair of accumulated changes. The study of a single nucleotide polymorphism in the genome of B. velezensis revealed nine point substitutions, three of which are in intergenic regions, six in protein-coding genes, three of them are missense mutations, two nucleotide deletions leading to a shift in the reading frame, and one synonymous substitution. The profiles of the housekeeping genes were determined during MLST typing and it was found that the allelic profiles obtained for B. velezensis T15.2 and 924 strains do not correspond to any of the previously described sequence types. The presented results indicate the ability of B. velezensis bacteria to maintain the viability of spores and the integrity of the genome for a long time under extreme conditions of outer space, which is important for the problem of planetary protection, as well as the potential possibility of performing biotechnological processes based on B. velezensis during space exploration.
摘要：
孢子形成细菌对负面环境条件具有独特的抵抗力，包括侵略性的空间因素，并且是在分子水平上研究适应机制和生存策略的绝佳模型。这项研究分析了巴西芽孢杆菌的基因组，作为测试空间实验的一部分，在国际空间站外表面的外层空间暴露2年后仍然可行。对展示菌株和地面对照的基因组草案进行的比较分析未发现显着变化；平均核苷酸同一性为99.98％，这表明微生物在太空条件下保持基因组稳定性的能力，由于细菌孢子的胁迫抗性增加和累积变化的修复系统的有效操作。对维氏芽孢杆菌基因组中的单核苷酸多态性的研究揭示了九个点替换，其中三个在基因间区域，六个蛋白质编码基因，其中三个是错义突变，两个核苷酸缺失导致阅读框的移动，和一个同义词替换。在MLST分型过程中确定了管家基因的概况，发现从维氏芽孢杆菌T15.2和924菌株获得的等位基因概况与任何先前描述的序列类型都不对应。结果表明，在极端的外太空条件下，维氏芽孢杆菌能够长期维持孢子的活力和基因组的完整性，这对行星保护问题很重要，以及在太空探索过程中基于B.velezensis进行生物技术过程的潜在可能性。
