小球藻对有机磷阻燃剂TDCPP暴露的响应与适应机制研究

Tris (1,3-dichloro-2-propyl) phosphate (TDCPP) is a widely used chlorinated organophosphorus flame retardant in the world. In recent years, It has been frequently detected in aquatic environment and its water environmental safety has attracted increasing attention. However, the available toxicological data of TDCPP are limited, and there is no report on the effect of TDCPP on microalgae, the primary producers in aquatic ecosystem. Our previous research showed that the biological effect of TDCPP on chlorella vulgaris was time-dependent, that is, chlorella vulgaris could gradually repair the damage caused by TDCPP with the exposure time. Photosynthetic system is the potential action site of TDCPP. Based on the time-dependent toxicity of TDCPP, the damage mechanism of TDCPP and the adaptation strategy of Chlorella vulgaris will be further studied in this project: the dynamic changes of photosynthesis reaction process and thylakoid membrane components under TDCPP exposure will be analyzed to reveal the inhibition mechanism of TDCPP on photosynthesis; the TDCPP removal and photosynthetic recovery characteristics will be studied to explore the adaptive mechanism of Chlorella vulgaris to TDCPP. The results will provide valuable references for aquatic toxicology research and aquatic ecological risk assessment of TDCPP.

磷酸三(1,3-二氯-2-丙基)酯(TDCPP)是一种全球广泛使用的氯代有机磷阻燃剂，近年来在水环境中被频繁检出，其水环境安全性日益引发关注。但目前已有的TDCPP毒理学数据有限，未见对水生态系统初级生产者-微藻影响的报道。申请人以小球藻为受试生物，发现TDCPP对小球藻的生物学效应呈现特殊的时间依赖性特征，即随着TDCPP暴露时间的延长，小球藻可逐渐修复其对自身造成的损伤。光合系统是TDCPP作用的一个关键部位。本项目将基于TDCPP的时间依赖毒性特征，深入研究TDCPP的伤害机理以及小球藻的适应策略：分析TDCPP暴露下光合作用反应过程及类囊体膜结构组分的动态变化，解析TDCPP对光合作用的抑制机理；通过研究小球藻对TDCPP的去除以及受损光合系统的恢复特征，探讨小球藻对TDCPP的适应机制。研究结果将为TDCPP的水生毒理学研究和水生态风险评估提供重要数据参考。

有机磷阻燃剂（OPFRs）是一类新型有机污染物，普遍存在于各种环境介质中，其毒性效应及生态风险受到高度重视。而OPFRs对于水生生态系统初级生产者-微藻的影响及机制研究较少。本项目前期发现小球藻在高浓度磷酸三(1,3-二氯-2-丙基)酯(TDCPP)暴露下表现非常强的生长恢复能力，以此为基础研究发现：（1）TDCPP暴露下，小球藻光合活性与生长抑制率变化趋势一致，而细胞未受到ROS介导的氧化损伤。（2）深入分析TDCPP对光合作用反应过程及光合系统结构组分的影响，发现光系统II（PSII）反应中心是TDCPP在小球藻光合系统中的作用靶点；对比添加和不添加叶绿体蛋白从头合成抑制剂（氯霉素）下，小球藻光合进程和PSII组成亚基的恢复差异，揭示PSII修复循环参与TDCPP暴露下光合系统的修复过程。（3）高效液相色谱-串联质谱法(HPLC-MS/MS)测定培养基、藻细胞表面和内部的TDCPP动态变化，证明TDCPP生物转化是小球藻强大适应能力的机制之一。（4）利用RNA-Seq高通量测序技术研究小球藻对TDCPP生物转化的分子机制。经基因功能注释与差异表达基因筛选，TDCPP处理组中紫色酸性磷酸酶（PAP）相关编码基因表达显著升高，推测PAP可能是参与TDCPP降解的水解酶，但仍需进一步研究。以上研究结果对于TDCPP的生态风险评估具有重要意义。