College of Environmental & Natural Resources, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China.
College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Chemosphere. 2023 May;324:138373. doi: 10.1016/j.chemosphere.2023.138373. Epub 2023 Mar 9.
Cadmium (Cd), as one of the most carcinogenic substances, poses a great threat to human health. With the development of microbial remediation technology, the necessity for urgent research into the mechanism of Cd toxicity to bacteria has arisen. In this study, a highly Cd-tolerant strain (up to 225 mg/L) was isolated and purified from Cd-contaminated soil, which was identified by 16S rRNA as a strain of Stenotrophomonas sp., thus manually designated as SH225. By testing OD of the strain, we indicated that Cd concentrations below 100 mg/L had no discernible impact on the biomass of SH225. When the Cd concentration was over 100 mg/L, the cell growth was significantly inhibited, while the number of extracellular vesicles (EVs) was greatly elevated. After extraction, cell-secreted EVs were confirmed to contain large amounts of Cd cations, highlighting the crucial function of EVs in the Cd detoxification of SH225. Meanwhile, the TCA cycle was vastly enhanced, suggesting that the cells provided adequate energy supply for EVs transport. Thus, these findings emphasized the crucial role played by vesicles and TCA cycle in Cd detoxification.
镉 (Cd) 作为最具致癌性的物质之一，对人类健康构成了极大的威胁。随着微生物修复技术的发展，迫切需要研究细菌对 Cd 毒性的作用机制。本研究从 Cd 污染土壤中分离和纯化出一株高 Cd 耐受性菌株（高达 225mg/L），通过 16S rRNA 鉴定为 Stenotrophomonas 属菌株，因此人工命名为 SH225。通过测试菌株的 OD 值，我们表明 Cd 浓度低于 100mg/L 对 SH225 的生物量没有明显影响。当 Cd 浓度超过 100mg/L 时，细胞生长受到明显抑制，而细胞外囊泡 (EVs) 的数量大大增加。提取后，证实细胞分泌的 EVs 中含有大量的 Cd 阳离子，这突出了 EVs 在 SH225 的 Cd 解毒中的关键作用。同时，三羧酸 (TCA) 循环大大增强，表明细胞为 EVs 的运输提供了充足的能量供应。因此，这些发现强调了囊泡和 TCA 循环在 Cd 解毒中的关键作用。
