Wu Yun, Guo Zhiqiang, Zhang Wei, Tan Qiaoguo, Zhang Li, Ge Xinlei, Chen Mindong
Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control (AEMPC), Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials (ECM), School of Environmental Science and Engineering, Nanjing University of Information Science &Technology (NUIST), Nanjing 210044, China.
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
Sci Rep. 2016 Oct 25;6:35935. doi: 10.1038/srep35935.
Heavy metals activate the synthesis of phytochelatins (PCs), while the induced PCs might affect metal uptake via chelating intracellular free metals. However, the relationship of PCs to metal uptake is poorly understood. In this study, we examined the kinetics of cadmium (Cd) accumulation and the synthesis of PCs in a marine diatom, Thalassiosira weissflogii, under different irradiance levels. Irradiance alone could not change the concentrations of PCs in the Cd-free treatments, while higher irradiance accelerated the induction of intracellular PCs at the same [Cd] level. PC-SH (2 × PC + 3 × PC + 4 × PC) was bound with Cd at a stoichiometric ratio of 2 to 49 in our short-term uptake experiments, indicating that PC induction is sufficient to serve as the first line of defense against Cd stress. A positive linear correlation between the induction rate of PCs and the Cd uptake rate was observed, while the ratio of the PC content to intracellular Cd varied greatly when the irradiance was increased several fold. Because metal uptake has been successfully used in predicting acute metal toxicity, our findings are helpful for understanding the role of PCs in metal detoxification and developing PCs as biomarkers for metal sensitivity.
重金属会激活植物螯合肽（PCs）的合成，而诱导产生的PCs可能会通过螯合细胞内的游离金属来影响金属的吸收。然而，PCs与金属吸收之间的关系却鲜为人知。在本研究中，我们检测了海洋硅藻威氏海链藻（Thalassiosira weissflogii）在不同光照水平下镉（Cd）积累的动力学以及PCs的合成情况。在无Cd处理中，单独的光照无法改变PCs的浓度，而在相同的[Cd]水平下，较高的光照会加速细胞内PCs的诱导。在我们的短期吸收实验中，PC-SH（2×PC + 3×PC + 4×PC）与Cd以2比49的化学计量比结合，这表明PCs的诱导足以作为抵御Cd胁迫的第一道防线。我们观察到PCs的诱导速率与Cd吸收速率之间呈正线性相关，而当光照增加数倍时，PC含量与细胞内Cd的比值变化很大。由于金属吸收已成功用于预测急性金属毒性，我们的研究结果有助于理解PCs在金属解毒中的作用，并将PCs开发为金属敏感性的生物标志物。
