Bioengineering Laboratory, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Porto, Portugal; CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal.
LEPABE, Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal.
J Hazard Mater. 2015 Oct 15;296:82-92. doi: 10.1016/j.jhazmat.2015.04.022. Epub 2015 Apr 9.
The green alga Pseudokirchneriella subcapitata has been widely used in ecological risk assessment, usually based on the impact of the toxicants in the alga growth. However, the physiological causes that lead algal growth inhibition are not completely understood. This work aimed to evaluate the biochemical and structural modifications in P. subcapitata after exposure, for 72 h, to three nominal concentrations of Cd(II), Cr(VI), Cu(II) and Zn(II), corresponding approximately to 72 h-EC10 and 72 h-EC50 values and a high concentration (above 72 h-EC90 values). The incubation of algal cells with the highest concentration of Cd(II), Cr(VI) or Cu(II) resulted in a loss of membrane integrity of ~16, 38 and 55%, respectively. For all metals tested, an inhibition of esterase activity, in a dose-dependent manner, was observed. Reduction of chlorophyll a content, decrease of maximum quantum yield of photosystem II and modification of mitochondrial membrane potential was also verified. In conclusion, the exposure of P. subcapitata to metals resulted in a perturbation of the cell physiological status. Principal component analysis revealed that the impairment of esterase activity combined with the reduction of chlorophyll a content were related with the inhibition of growth caused by a prolonged exposure to the heavy metals.
铜绿微囊藻已被广泛应用于生态风险评估中，通常基于毒物对藻类生长的影响。然而，导致藻类生长抑制的生理原因尚不完全清楚。本研究旨在评估铜绿微囊藻在暴露于三种名义浓度的 Cd(II)、Cr(VI)、Cu(II)和 Zn(II)下 72 小时后的生化和结构变化，这些浓度分别约为 72 h-EC10、72 h-EC50 和高浓度（高于 72 h-EC90 值）。用最高浓度的 Cd(II)、Cr(VI)或 Cu(II)孵育藻类细胞会导致约 16%、38%和 55%的细胞膜完整性丧失。对于所有测试的金属，均观察到酯酶活性呈剂量依赖性抑制。叶绿素 a 含量减少、光合作用系统 II 的最大光量子产量下降以及线粒体膜电位改变也得到了验证。总之，金属暴露会干扰铜绿微囊藻的细胞生理状态。主成分分析表明，酯酶活性的损伤以及叶绿素 a 含量的减少与重金属暴露时间延长导致的生长抑制有关。
