Department of Biology, University of Trnava, Priemyselná 4, 918 43 Trnava, Slovak Republic.
Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic.
J Hazard Mater. 2017 Oct 5;339:200-207. doi: 10.1016/j.jhazmat.2017.06.035. Epub 2017 Jun 16.
Impact of exogenous ascorbic acid (AsA, 100μM) on acute metal toxicity (Pb and Hg, 24h of exposure to 100μM) in unicellular green alga Coccomyxa subellipsoidea was studied. Hg (often extensively) depleted amount of pigments, potassium, soluble proteins, endogenous AsA, non-protein thiols and nitric oxide signal but elevated ROS signal and activities of catalase and superoxide dismutase. Responses to Pb application (if any) were less visible with ROS signal being slightly elevated and amount of non-protein thiols being slightly reduced. Exogenous AsA considerably improved mainly Hg-induced damage at the level of oxidative stress and physiological parameters and evoked an increase in nitric oxide signal. Maximum amount of total Hg was almost 4-fold higher than that of Pb (36.5 vs. 9.73mg/g DW) and AsA depleted both total and intracellular accumulation. At the level of ascorbate-related proteins, exogenous AsA suppressed metal-induced expression and activity of MDHAR and APX but not of DHAR, which may indicate a role of DHAR in algal stress tolerance. Our data suggest that given Coccomyxa species is suitable candidate for remediation of Hg or Pb and that ascorbic acid effectively ameliorates metal-induced toxicity without side effects.
研究了外源性抗坏血酸（AsA，100μM）对单细胞绿藻球石藻（Coccomyxa subellipsoidea）急性金属毒性（Pb 和 Hg，暴露于 100μM 24 小时）的影响。Hg（通常大量）耗尽了色素、钾、可溶性蛋白质、内源性 AsA、非蛋白巯基和一氧化氮信号，但提高了 ROS 信号和过氧化氢酶和超氧化物歧化酶的活性。对 Pb 应用（如果有）的反应不太明显，ROS 信号略有升高，非蛋白巯基的含量略有降低。外源性 AsA 大大改善了主要由 Hg 引起的氧化应激和生理参数水平的损伤，并引起了一氧化氮信号的增加。总 Hg 的最大量几乎是 Pb 的 4 倍（36.5 与 9.73mg/g DW），并且 AsA 耗尽了总汞和细胞内积累。在抗坏血酸相关蛋白水平上，外源性 AsA 抑制了 MDHAR 和 APX 的金属诱导表达和活性，但不抑制 DHAR，这可能表明 DHAR 在藻类胁迫耐受中的作用。我们的数据表明，鉴于球石藻物种是修复 Hg 或 Pb 的合适候选物，抗坏血酸可有效减轻金属诱导的毒性而无副作用。
