Pradhan Arunava, Silva Carla O, Silva Carlos, Pascoal Cláudia, Cássio Fernanda
Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
Aquat Toxicol. 2016 Nov;180:227-235. doi: 10.1016/j.aquatox.2016.09.017. Epub 2016 Sep 28.
Commercial applications of nanometal oxides have increased concern about their release into natural waters and consequent risks to aquatic biota and the processes they drive. In forest streams, the invertebrate shredder Allogamus ligonifer plays a key role in detritus food webs by transferring carbon and energy from plant litter to higher trophic levels. We assessed the response profiles of oxidative and neuronal stress enzymatic biomarkers in A. ligonifer after 96h exposure to nanoCuO at concentration ranges <LC. To better understand the contribution of ionic form in nanoCuO-induced stress, Cu released from nanoCuO was quantified and the enzymatic responses to Cu exposure at similar effective concentrations were compared. The highest activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) were observed at concentrations <LC. The enzymatic activities decreased at effective concentrations between LC and LC. GR activity remained higher than in control at all concentrations. The activity of glutathione S-transferase (GST) increased whereas that of catalase (CAT) decreased at concentrations between LC and LC. The response patterns suggested that antioxidant enzymes could prevent oxidative stress at low concentrations (<LC) of nanoCuO, thereby contributing to the survival of A. ligonifer. At concentrations between LC and LC, effects of nanoparticulate or released ionic copper on enzyme activities were concentration-dependent, and led to oxidative stress and even to animal death. The activity of acetylcholinesterase (AChE) was strongly inhibited even at concentrations <LC, suggesting neuronal stress in A. ligonifer.
纳米金属氧化物的商业应用增加了人们对其释放到天然水体中以及随之对水生生物群及其驱动的过程造成风险的担忧。在森林溪流中，无脊椎动物碎食者利氏阿洛蜉蝣通过将碳和能量从植物凋落物转移到更高营养级，在碎屑食物网中发挥着关键作用。我们评估了利氏阿洛蜉蝣在暴露于浓度范围小于半数致死浓度（LC）的纳米氧化铜96小时后，氧化应激和神经应激酶生物标志物的反应情况。为了更好地理解纳米氧化铜诱导应激中离子形式的作用，对纳米氧化铜释放的铜进行了定量，并比较了在相似有效浓度下对铜暴露的酶反应。在浓度小于半数致死浓度时，观察到超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GPx）和谷胱甘肽还原酶（GR）的活性最高。在半数致死浓度和更高半数致死浓度之间的有效浓度下，酶活性下降。在所有浓度下，GR活性均高于对照组。在半数致死浓度和更高半数致死浓度之间的浓度下，谷胱甘肽S - 转移酶（GST）的活性增加，而过氧化氢酶（CAT）的活性下降。这些反应模式表明，抗氧化酶可以在纳米氧化铜低浓度（小于半数致死浓度）时预防氧化应激，从而有助于利氏阿洛蜉蝣的生存。在半数致死浓度和更高半数致死浓度之间的浓度下，纳米颗粒或释放的离子铜对酶活性的影响呈浓度依赖性，并导致氧化应激甚至动物死亡。即使在浓度小于半数致死浓度时，乙酰胆碱酯酶（AChE）的活性也受到强烈抑制，这表明利氏阿洛蜉蝣存在神经应激。
