Norwegian University of Science and Technology, Department of Biology, N-7491 Trondheim, Norway; SINTEF Materials and Chemistry, Environmental Technology, N-7465 Trondheim, Norway.
BioTrix, N-7022 Trondheim, Norway.
Aquat Toxicol. 2014 Oct;155:160-5. doi: 10.1016/j.aquatox.2014.06.019. Epub 2014 Jul 3.
Acute lethal toxicity, expressed as LC50 values, is a widely used parameter in risk assessment of chemicals, and has been proposed as a tool to assess differences in species sensitivities to chemicals between climatic regions. Arctic Calanus glacialis and boreal Calanus finmarchicus were exposed to mercury (Hg(2+)) under natural environmental conditions including sea temperatures of 2° and 10°C, respectively. Acute lethal toxicity (96 h LC50) and sub-lethal molecular response (GST expression; in this article gene expression is used as a synonym of gene transcription, although it is acknowledged that gene expression is also regulated, e.g., at translation and protein stability level) were studied. The acute lethal toxicity was monitored for 96 h using seven different Hg concentrations. The sub-lethal experiment was set up on the basis of nominal LC50 values for each species using concentrations equivalent to 50, 5 and 0.5% of their 96 h LC50 value. No significant differences were found in acute lethal toxicity between the two species. The sub-lethal molecular response revealed large differences both in response time and the fold induction of GST, where the Arctic species responded both faster and with higher mRNA levels of GST after 48 h exposure. Under the natural exposure conditions applied in the present study, the Arctic species C. glacialis may potentially be more susceptible to mercury exposure on the sub-lethal level.
急性致死毒性（LC50 值）是化学品风险评估中广泛使用的参数，它被提议作为一种工具，以评估不同物种对化学物质在气候区域间敏感性的差异。北极拟哲水蚤和北方真刺水蚤在包括 2°C 和 10°C 海水温度在内的自然环境条件下暴露于汞（Hg(2+)）中。研究了急性致死毒性（96 h LC50）和亚致死分子反应（GST 表达；在本文中，基因表达被用作基因转录的同义词，尽管人们承认基因表达也受到调控，例如在翻译和蛋白质稳定性水平上）。使用七种不同的 Hg 浓度监测了 96 h 的急性致死毒性。亚致死实验是基于每种物种的名义 LC50 值建立的，使用相当于其 96 h LC50 值的 50%、5%和 0.5%的浓度。这两个物种的急性致死毒性没有显著差异。亚致死分子反应在 GST 的反应时间和诱导倍数上都显示出很大的差异，其中北极物种在暴露 48 h 后 GST 的 mRNA 水平反应更快，诱导倍数更高。在本研究中应用的自然暴露条件下，北极种 C. glacialis 可能在亚致死水平上更容易受到汞暴露的影响。
