State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China.
State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China; Key Laboratory of Biodiversity of Aquatic Organisms, Harbin Normal University, Harbin 150025, China.
J Hazard Mater. 2024 Aug 5;474:134762. doi: 10.1016/j.jhazmat.2024.134762. Epub 2024 May 29.
Bioremediation of cadmium (Cd) pollution, a recognized low-carbon green environmental protection technology, is significantly enhanced by the discovery of Cd-tolerant microorganisms and their underlying tolerance mechanisms. This study presents Colpoda sp., a soil ciliate with widespread distribution, as a novel bioindicator and bioremediator for Cd contamination. With a 24 h-LC of 5.39 mg l and an IC of 24.85 μg l in Cd-contaminated water, Colpoda sp. achieves a maximum bioaccumulation factor (BAF) of 3.58 and a Cd removal rate of 32.98 ± 0.74 % within 96 h. The toxic responses of Colpoda sp. to Cd stress were assessed through cytological observation with transmission electron microscopy (TEM), oxidative stress kinase activity, and analysis of Cd-metallothionein (Cd-MTs) and the cd-mt gene via qRT-PCR. The integrated biomarker response index version 2 (IBRv2) and structural equation models (SEM) were utilized to analyze key factors and mechanisms, revealing that the up-regulation of Cd-MTs and cd-mt expression, rather than the oxidative stress system, is the primary determinant of Cd accumulation and tolerance in Colpoda sp. The ciliate's ability to maintain growth under 24.85 μg l Cd stress and its capacity to absorb and accumulate Cd particles from water into cells are pivotal for bioremediation. A new mathematical formula and regression equations based on Colpoda sp.'s response parameters have been established to evaluate environmental Cd removal levels and design remediation schemes for contaminated sites. These findings provide a novel bioremediation and monitoring pathway for Cd remobilization and accumulation in soil and water, potentially revolutionizing the governance of Cd pollution.
利用耐镉微生物及其耐受机制来修复镉污染是一种被广泛认可的低碳绿色环保技术，该技术得到了显著增强。本研究发现土壤纤毛虫 Colpoda sp. 是一种分布广泛的新型生物指示剂和生物修复剂，可用于镉污染。在受镉污染的水中，Colpoda sp. 的 24 h-LC 为 5.39 mg l，IC 为 24.85 μg l，其最大生物积累因子（BAF）为 3.58，96 h 内 Cd 的去除率为 32.98±0.74%。通过透射电子显微镜（TEM）观察细胞形态、氧化应激激酶活性以及通过 qRT-PCR 分析 Cd 金属硫蛋白（Cd-MTs）和 cd-mt 基因，评估 Colpoda sp. 对 Cd 胁迫的毒性反应。利用整合生物标志物响应指数 2 版（IBRv2）和结构方程模型（SEM）分析关键因素和机制，结果表明，Cd-MTs 和 cd-mt 表达的上调而非氧化应激系统，是 Colpoda sp. 积累和耐受 Cd 的主要决定因素。纤毛虫在 24.85 μg l Cd 胁迫下维持生长的能力以及从水中吸收和将 Cd 颗粒积累到细胞内的能力，对生物修复至关重要。基于 Colpoda sp. 的响应参数，建立了一个新的数学公式和回归方程，用于评估环境中 Cd 的去除水平，并为污染场地设计修复方案。这些发现为土壤和水中 Cd 的再迁移和积累的生物修复和监测提供了新途径，可能会彻底改变 Cd 污染的治理方式。
