Science of the Total Environment ( IF 9.8 ) Pub Date : 2020-12-03 , DOI: 10.1016/j.scitotenv.2020.143907 Antoine Minet , Alain Manceau , Anaïs Valada-Mennuni , Maud Brault-Favrou , Carine Churlaud , Jérôme Fort , Thành Nguyen , Jérôme Spitz , Paco Bustamante , Thomas Lacoue-Labarthe
Mercury (Hg), one of the elements most toxic to biota, accumulates within organisms throughout their lifespans and biomagnifies along trophic chain. Due to their key role in marine systems, cephalopods constitute a major vector of Hg in predators. Further, they grow rapidly and display complex behaviours, which can be altered by neurotoxic Hg. This study investigated Hg concentrations within 80 cephalopod specimens sampled in the Bay of Biscay, which belonged to five species: Eledone cirrhosa, Sepia officinalis, Loligo vulgaris, Todaropsis eblanae and Illex coindetii. Hg concentrations were measured in the digestive gland, the mantle muscle and optic lobes of the brain. The digestive gland and the mantle were tissues with the most concentrated Hg among all species considered (up to 1.50 μg.g-1 dw), except E. cirrhosa. This benthic cephalopod had 1.3-fold higher Hg concentrations in the brain (up to 1.89 μg.g-1 dw) than the mantle, while other species had 2-fold lower concentrations of Hg in the brain than in the mantle. Brain-Hg concentrations can be predicted from muscle-Hg concentrations for a given species, which facilitates the assessment of Hg toxicokinetics in cephalopods. In the most contaminated E. cirrhosa individual, the chemical form of Hg in its digestive gland, mantle muscle, and optic lobes, was determined using High energy-Resolution X-ray Absorption Near Edge Structure (HR XANES) spectroscopy. In the digestive gland, 33 ± 11% of total Hg was inorganic Hg speciated as a dicysteinate complex (Hg(Cys)2), which suggested that the demethylation of dietary MeHg occurs in the organ. All Hg found in the mantle muscle and the optic lobes is methylated and bound to one cysteinyl group (MeHgCys complex), which implies that dietary MeHg is distributed to these tissues via the bloodstream. These results raised the questions regarding interspecific differences observed regarding Hg brain concentrations and the possible effect of Hg on cephalopod functional brain plasticity and behaviour.
中文翻译:
五个头足类动物组织中的汞:神经系统的第一批数据
汞(Hg)是对生物区系最具毒性的元素之一,它在生物的整个生命周期内积累并沿营养链生物放大。由于其在海洋系统中的关键作用,头足类动物是捕食者中汞的主要媒介。此外,它们迅速生长并表现出复杂的行为,这可由神经毒性汞改变。这项研究调查了在比斯开湾采样的80个头足类标本中的汞含量,该标本属于五个物种:硬皮Eledone,中药乌贼墨,寻常型低聚李子,Todaropsis eblanae和Illex coindetii。在消化腺,大脑的幔层和视神经叶中测量汞的浓度。消化腺和地幔是所有考虑的物种中汞含量最高的组织(高达1.50μg.g -1 dw),除了硬皮大肠杆菌。这种底栖头足类动物的脑中Hg浓度(高达1.89μg.g -1 dw)比地幔高1.3倍,而其他物种的脑中Hg浓度则比地幔低2倍。可以从给定物种的肌肉汞浓度预测脑汞浓度,这有助于评估头足类动物的汞毒代动力学。在污染最严重的大肠杆菌中使用高能量分辨X射线吸收近边缘结构(HR XANES)光谱法确定了Hg在其消化腺,地幔肌肉和视裂中的化学形式。在消化腺中,总Hg的33±11%是无机汞,以半胱氨酸配合物(Hg(Cys)2)的形式存在,这表明膳食中MeHg的去甲基化发生在器官中。在外套层肌肉和视神经叶中发现的所有Hg都被甲基化并结合到一个半胱氨酸基团(MeHgCys复合物),这意味着饮食中的MeHg通过血流分布到这些组织。这些结果引起了关于汞大脑浓度观察到的种间差异以及汞对头足类功能性大脑可塑性和行为的可能影响的问题。