In this study, the Pb-resistant strain S24, which contains quorum sensing (QS) systems responsible for N-acyl homoserine lactone (AHL) production, was investigated for QS system-mediated Pb stabilization and the underlying mechanisms. Whole-genome sequence analysis revealed the QS SinI/R and TraI/R systems in strain S24. Subsequently, strains S24 and the S24∆, S24∆, S24∆, and S24∆- mutants were constructed and compared for QS SinI/SinR-TraI/TraR system-mediated Pb stabilization in the solution and the mechanisms involved. After 5 days of incubation, strain S24 significantly decreased the Pb concentration in the Pb-contaminated solution compared with the mutants. The S24∆- mutant exhibited reduced Pb stabilization and AHL activity than the other mutants. The S24∆- mutant had significantly greater Pb concentrations in the solution and lower cell surface-adsorbed and extracellular precipitated Pb (PbS) contents as well as lower expression of HS-producing genes of and than did strain S24. Furthermore, the S24∆- mutant displayed reduced interactions between the hydroxyl, amino, carboxyl, and ether groups and Pb, compared with strain S24. These findings implied the vital role of the SinI/SinR-TraI/TraR systems in strain S24 for Pb stabilization through enhanced cell surface adsorption and extracellular precipitation in Pb-polluted aquatic environments.

中文翻译：

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群体感应 SinI/SinR-TraI/TraR 系统促进 Ensifer adhaerens S24 在铅污染的水生环境中稳定铅


在本研究中，对含有负责 N-酰基高丝氨酸内酯 (AHL) 生产的群体感应 (QS) 系统的 Pb 抗性菌株 S24 进行了 QS 系统介导的 Pb 稳定及其潜在机制的研究。全基因组序列分析揭示了菌株 S24 中的 QS SinI/R 和 TraI/R 系统。随后，构建了菌株 S24 和 S24Δ、S24Δ、S24Δ 和 S24Δ- 突变体，并比较了 QS SinI/SinR-TraI/TraR 系统介导的溶液中 Pb 稳定作用以及所涉及的机制。培养5天后，与突变体相比，菌株S24显着降低了Pb污染溶液中的Pb浓度。与其他突变体相比，S24Δ-突变体表现出降低的 Pb 稳定性和 AHL 活性。与菌株 S24 相比，S24Δ-突变体溶液中的 Pb 浓度显着更高，细胞表面吸附和细胞外沉淀的 Pb (PbS) 含量更低，并且 HS 产生基因的表达更低。此外，与菌株 S24 相比，S24Δ- 突变体显示羟基、氨基、羧基和醚基与 Pb 之间的相互作用减少。这些发现表明菌株 S24 中的 SinI/SinR-TraI/TraR 系统通过增强细胞表面吸附和细胞外沉淀在铅污染的水生环境中对铅的稳定发挥着至关重要的作用。