The mechanism of perchlorate resistance of the desert cyanobacterium Chroococcidiopsis sp. CCMEE 029 was investigated by assessing whether the pathways associated with its desiccation tolerance might play a role against the destabilizing effects of this chaotropic agent. During 3 weeks of growth in the presence of 2.4 mM perchlorate, an upregulation of trehalose and sucrose biosynthetic pathways was detected. This suggested that in response to the water stress triggered by perchlorate salts, these two compatible solutes play a role in the stabilization of macromolecules and membranes as they do in response to dehydration. During the perchlorate exposure, the production of oxidizing species was observed by using an oxidant-sensing fluorochrome and determining the expression of the antioxidant defense genes, namely superoxide dismutases and catalases, while the presence of oxidative DNA damage was highlighted by the over-expression of genes of the base excision repair. The involvement of desiccation-tolerance mechanisms in the perchlorate resistance of this desert cyanobacterium is interesting since, so far, chaotropic-tolerant bacteria have been identified among halophiles. Hence, it is anticipated that desert microorganisms might possess an unrevealed capability of adapting to perchlorate concentrations exceeding those naturally occurring in dry environments. Furthermore, in the endeavor of supporting future human outposts on Mars, the identified mechanisms might contribute to enhance the perchlorate resistance of microorganisms relevant for biologically driven utilization of the perchlorate-rich soil of the red planet.

中文翻译：

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深入了解沙漠蓝藻 Chroococcidiopsis sp 的离液耐受性。029（色球菌属，蓝藻菌）

沙漠蓝藻Chroococcidiopsis sp.的高氯酸盐抗性机制。通过评估与其耐干燥性相关的途径是否可能对这种离液剂的不稳定作用发挥作用，对 CCMEE 029 进行了研究。在 2.4 mM 高氯酸盐存在下的 3 周生长期间，检测到海藻糖和蔗糖生物合成途径的上调。这表明，为了响应高氯酸盐引发的水胁迫，这两种相容的溶质在稳定大分子和膜方面发挥着作用，就像它们响应脱水一样。在高氯酸盐暴露期间，通过使用氧化剂感应荧光染料并确定抗氧化防御基因（即超氧化物歧化酶和过氧化氢酶）的表达来观察氧化物质的产生，同时氧化性 DNA 损伤的存在通过过表达碱基切除修复的基因。这种沙漠蓝细菌的高氯酸盐抗性中涉及干燥耐受机制很有趣，因为到目前为止，已在嗜盐菌中鉴定出耐离液细菌。因此，预计沙漠微生物可能具有一种未被揭示的适应高氯酸盐浓度超过干燥环境中自然存在的能力。此外，在支持未来人类在火星上的前哨基地的努力中，所确定的机制可能有助于增强与生物驱动利用红色星球富含高氯酸盐的土壤相关的微生物的高氯酸盐抗性。