Key Laboratory of Marine Environment and Ecology (Ministry of Education), College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, People's Republic of China.
Department of Biology, University of Alabama at Birmingham, Birmingham, AL, 35924, USA.
Environ Sci Pollut Res Int. 2021 Sep;28(36):50908-50918. doi: 10.1007/s11356-021-14318-2. Epub 2021 May 11.
To understand the arsenic (As) toxicity to aquatic organisms in the phosphors-polluted aquatic ecosystem, the growth, the physiological response of Chlorella vulgaris exposed to As (V), and the underlying mechanism were investigated under different phosphorus (P) levels (0, 6, 13, 32 μM). Results showed that As toxicity to the marine microalga C. vulgaris was enhanced under P-limited condition. P supply distinctly altered the effect of As on the light-harvesting efficiency of photosystem. Insufficient P supply also resulted in an enhanced level of membrane integrity loss, which probably facilitated As entering cells and led to stronger toxicity to C. vulgaris under low P supply. At high concentrations of As, the relative superoxide dismutase (SOD) activity was significantly enhanced. When phosphorus was limited, the activation of peroxidase (POD) was significantly enhanced after adding As (V). When intracellular SOD activity was at its highest level, the level of membrane peroxidation (MDA) was also at the highest level, and membrane peroxidation level was positively related to the level of membrane integrity loss (Pearson R=0.8977). These results suggested that alternation of light-harvesting efficiency of photosystem and As-induced oxidative damage, resulting in membrane peroxidation and integrity loss, were the possible mechanism of As toxicity to C. vulgaris. This study provided insight into the understanding of As toxicity to algae in the eutrophication aquatic system and the potential application of algae in As remediation.
为了了解富磷水生生态系统中砷（As）对水生生物的毒性，在不同磷（P）水平（0、6、13、32 μM）下研究了小球藻暴露于 As（V）时的生长和生理反应及其潜在机制。结果表明，在 P 限制条件下，As 对海洋微藻小球藻的毒性增强。P 的供应明显改变了 As 对光系统捕光效率的影响。P 供应不足也导致膜完整性丧失水平增强，这可能促进了 As 进入细胞，并在低 P 供应下导致对 C. vulgaris 的毒性更强。在高浓度的 As 下，相对超氧化物歧化酶（SOD）活性显著增强。当磷受到限制时，添加 As（V）后过氧化物酶（POD）的活性明显增强。当细胞内 SOD 活性达到最高水平时，膜过氧化（MDA）水平也达到最高水平，膜过氧化水平与膜完整性丧失水平呈正相关（Pearson R=0.8977）。这些结果表明，光系统捕光效率的改变和 As 诱导的氧化损伤导致膜过氧化和完整性丧失，可能是 As 对 C. vulgaris 毒性的机制。本研究深入了解了富营养化水体中藻类对 As 的毒性以及藻类在 As 修复中的潜在应用。
