Acidithiobacillus thiooxidans (A. thiooxidans) is often used for sulfur-bearing ores bioleaching, but its adaptive mechanism to harsh environments remains unclear. Here, we explored the adaptive mechanism of A. thiooxidans in the process of low-grade chalcopyrite bioleaching based on the physiology and comparative transcriptome analysis. It was indicated that A. thiooxidans maintains intracellular pH homeostasis by regulating unsaturated fatty acids, especially cyclopropane fatty acids, intracellular ATP, amino acid metabolism, and antioxidant factors. Comparative transcriptome analysis indicated that the key genes involved in sulfur oxidation, sor and soxABXYZ, were significantly up-regulated, generating more energy to resist extreme environmental stress by more active sulfur metabolism. Confocal laser scanning microscope analysis found that down-regulation of flagellar-related genes was likely to promote the biofilm formation. System-level understanding of leaching microorganisms under extreme stress can contribute to the evolution of these extremophiles via genetic engineering modification work, which further improves bioleaching in future.

中文翻译：

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基于生理和比较转录组学分析，硫代酸性硫杆菌CCTCC M 2012104在低级黄铜矿生物浸出过程中的胁迫适应机制。

酸性硫氧杆菌硫氧化物（A. thiooxidans）通常用于含硫矿石的生物浸出，但其对恶劣环境的适应机制仍不清楚。在这里，我们基于生理学和比较转录组分析，探讨了硫氧化农杆菌在低级黄铜矿生物浸出过程中的适应机制。结果表明，硫氧化农杆菌通过调节不饱和脂肪酸，特别是环丙烷脂肪酸，细胞内ATP，氨基酸代谢和抗氧化因子来维持细胞内pH稳态。比较转录组分析表明，涉及硫氧化的关键基因sor和soxABXYZ被显着上调，通过更活跃的硫代谢产生更多的能量来抵抗极端的环境压力。共聚焦激光扫描显微镜分析发现，鞭毛相关基因的下调可能促进了生物膜的形成。通过基因工程改造工作，系统级了解极端压力下的浸出微生物可有助于这些极端微生物的进化，这将进一步改善未来的生物浸出。