The microbial reduction of selenite to elemental selenium nanoparticles (SeNPs) is thought to be an effective detoxification process of selenite for many bacteria. In this study, sp. ES129 and sp. ES111 with high selenite reduction efficiency or tolerance were selected for systematic and comparative studies on their performance in selenite removal and valuable SeNPs recovery. The kinetic monitoring of selenite reduction showed that the highest transformation efficiency of selenite to SeNPs was achieved at a concentration of 4.24 mM for ES129 and 4.88 mM for ES111. Ultramicroscopic analysis suggested that the SeNPs produced by ES111 and ES129 had been formed in cytoplasm and subsequently released to extracellular space through cell lysis process. Furthermore, the transcriptome analysis indicated that the expression of genes involved in bacillithiol biosynthesis, selenocompound metabolism and proline metabolism were significantly up-regulated during selenite reduction, suggesting that the transformation of selenite to Se may involve multiple pathways. Besides, the up-regulation of genes associated with nucleotide excision repair and antioxidation-related enzymes may enhance the tolerance of bacteria to selenite. Generally, the exploration of selenite reduction and tolerance mechanisms of the highly selenite-tolerant bacteria is of great significance for the effective utilization of microorganisms for environmental remediation.

中文翻译：

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从含硒土壤中分离出的高度耐亚硒酸盐细菌将亚硒酸盐还原为硒纳米颗粒


微生物将亚硒酸盐还原为元素硒纳米颗粒（SeNP）被认为是亚硒酸盐对许多细菌的有效解毒过程。在这项研究中，sp。 ES129 和 sp。选择具有高亚硒酸盐还原效率或耐受性的ES111对其在亚硒酸盐去除和有价值的SeNPs回收方面的性能进行系统和比较研究。亚硒酸盐还原的动力学监测表明，ES129 的亚硒酸盐转化为 SeNP 的效率最高，浓度为 4.24 mM，ES111 的浓度为 4.88 mM。超显微镜分析表明，ES111和ES129产生的SeNPs在细胞质中形成，随后通过细胞裂解过程释放到细胞外空间。此外，转录组分析表明，在亚硒酸盐还原过程中，参与杆菌硫醇生物合成、硒化合物代谢和脯氨酸代谢的基因表达显着上调，表明亚硒酸盐向硒的转化可能涉及多种途径。此外，与核苷酸切除修复和抗氧化相关酶相关的基因的上调可能会增强细菌对亚硒酸盐的耐受性。总之，探索高耐亚硒酸细菌的亚硒酸还原和耐受机制对于有效利用微生物进行环境修复具有重要意义。