| 谢伟霞,朱梦可,范瑞娟,闫兴富.抗镉菌株的吸附特性及抗镉机制[J].农业环境科学学报,2024,43(12):2889-2900. |
| 抗镉菌株的吸附特性及抗镉机制 |
| Cadmium adsorption characteristics and mechanisms of cadmium-resistant strains |
| 投稿时间：2024-01-05 |
| DOI：10.11654/jaes.2024-0017 |
| 中文关键词: 重金属 Cd 生物吸附 微生物修复 转录组 |
| 英文关键词: heavy metal cadmium adsorption microbial remediation transcriptome |
| 基金项目:国家自然科学基金项目（21966001）；宁夏自然科学基金优秀青年项目（2021AAC05012）；农产品产地土壤与农产品重金属协同检测项目（2021-87）；北方民族大学研究生创新项目（YCX23192） |
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| 中文摘要: |
| 以前期筛选获得的3株镉（Cd）抗性菌株Stenotrophomonas sp.Cd-2、Achromobacter sp.Cd-3和Staphylococcus sp.Cd-7为研究对象，分析了菌体吸附剂对Cd2+的吸附特性及Cd2+胁迫下3株菌胞外聚合物（Extracellular polymeric substances，EPS）的分泌量，并在此基础上选择菌株Cd-3，通过转录组测序技术分析了其受Cd2+胁迫后基因表达谱差异，对其抗Cd机制进行了探讨。结果表明，在pH 7、温度30℃、培养时间120 min、Cd2+浓度为20~100 mg·L-1、吸附剂浓度1 g·L-1（ Cd-7）和8 g·L-1（ Cd-2、Cd-3）时，菌株吸附剂对Cd2+的吸附率最高，达90%以上，吸附过程均符合Langmuir模型和准二级动力学模型，说明3株菌对Cd2+的吸附属于单分子层吸附，且吸附速率主要受化学吸附限制。EPS测定表明，3株菌在Cd2+胁迫下主要通过蛋白组分络合Cd2+来阻止其进入细胞。转录组测序结果发现，Cd-3受Cd2+胁迫后与生长代谢、氧化还原和跨膜转运相关的基因表达上调，说明菌株Cd-3通过调节这些基因的表达来抵抗Cd2+的胁迫。 |
| 英文摘要: |
| The focus of this study was the mechanism of cadmium resistance of three previously screened bacterial strains, i. e., Stenotrophomonas sp. Cd-2, Achromobacter sp. Cd-3, and Staphylococcus sp. Cd-7. The characteristics of bacterial adsorbents for Cd2+ and the secretion of extracellular polymeric substances（EPS）of the three strains under Cd2+ stress were investigated. The gene expression profile of strain Cd-3 was examined using transcriptome sequencing technology after exposure to Cd2+ stress, with the aim of investigating the mechanisms underlying the resistance to Cd. The results showed that the strains exhibited the highest adsorption rate of Cd 2+, reaching over 90%, under the following conditions：pH, 7; temperature, 30 ℃; contact time, 120 min; Cd2+ concentrations, 20~100 mg·L-1; bacterial biosorbent concentrations, 1 g·L-1（Cd-7）and 8 g·L-1（Cd-2, Cd-3）. The adsorption processes followed the Langmuir model and pseudosecond-order kinetic model, indicating that the adsorption of Cd2+ by these three strains is via a single molecular layer, with the adsorption rate mainly limited by chemical adsorption. The EPS assay revealed that, under conditions of Cd2+ stress, the three strains primarily inhibited the entry of Cd2+ into cells through extracellular protein complexation. The transcriptome sequencing results showed that strain Cd-3 exhibited a response to Cd2+ stress by upregulating genes associated with growth metabolism, redox reactions, and transmembrane transport, indicating that strain Cd-3 was resistant to Cd2+ stress by regulating the expression of these genes. |
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