Mouneyrac C, Amiard J C, Amiard-Triquet C, Cottier A, Rainbow P S, Smith B D
IRFA, Département des Sciences de la Vie et de la Terre, Laboratoire d'Ecologie Animale, 44, rue Rabelais, 49100 Angers, France.
Aquat Toxicol. 2002 Jun;57(4):225-42. doi: 10.1016/s0166-445x(01)00201-6.
The induction of metallothionein-like proteins (MTLP) as biomarkers of trace metal pollution has been investigated in the talitrid amphipod Orchestia gammarellus, an established biomonitor of trace metal availabilities in coastal areas. Sensitivity to metal exposure, MTLP and copper and zinc concentrations have been examined in amphipods from a metal-contaminated site (Dulas Bay, Wales) and two clean sites (Millport, Scotland and Bradwell, England). Groups of 10 amphipods from Dulas Bay and Millport were exposed separately to one of a concentration series (1, 3.16, 10, 31.6, 100 microM) of Cu or Zn for 17 days at 10 degrees C. Specimens from Bradwell were exposed under similar conditions but the experiment was extended to 25 days with intermediate samplings at 5, 10 and 17 days and additional groups were exposed to a mixture of Cu+Zn (7:10 molar ratio). In addition, specimens from Millport were exposed to 1 or 31.6 microM Cd for 17 days. Amphipods from Dulas Bay, which had been chronically exposed to metals in their natural environment had not acquired any tolerance to Cu and Zn since the lowest LC 50s were registered in these samples. Whatever the origin of the amphipods experimentally exposed to metals and whatever the dose of exposure, both Cu and Zn remained approximately equally distributed between cytosolic and insoluble fractions in the amphipods, suggesting that mechanisms of metal storage were identical over the whole range of conditions. Concentrations of MTLP were higher in O. gammarellus from Dulas Bay than in those from Millport analysed directly after collection, although laboratory exposures to dissolved Cd, Cu or Zn have failed to demonstrate differences in the induction of MTLP between amphipods from the clean or contaminated sites. A potential role for metallothionein-like proteins as biomarkers is thus unlikely although it remains plausible that turnover of these proteins does increase in response to increased metal challenges, enabling MTLP to play a role in metal detoxification.
在沿海地区痕量金属有效性的既定生物监测器——海蟑螂（Orchestia gammarellus）中，对作为痕量金属污染生物标志物的类金属硫蛋白（MTLP）的诱导情况进行了研究。研究人员检测了来自金属污染场地（威尔士的杜拉斯湾）以及两个清洁场地（苏格兰的米尔波特和英格兰的布拉德韦尔）的海蟑螂对金属暴露的敏感性、MTLP以及铜和锌的浓度。将来自杜拉斯湾和米尔波特的每组10只海蟑螂分别暴露于一系列浓度（1、3.16、10、31.6、100微摩尔）的铜或锌中，在10摄氏度下暴露17天。来自布拉德韦尔的样本在类似条件下暴露，但实验延长至25天，在第5、10和17天进行中间取样，另外几组暴露于铜 + 锌混合物（摩尔比7:10）中。此外，将来自米尔波特的样本暴露于1或31.6微摩尔的镉中17天。在自然环境中长期暴露于金属的杜拉斯湾海蟑螂，由于在这些样本中记录到最低的半数致死浓度（LC50），所以对铜和锌没有获得任何耐受性。无论实验中暴露于金属的海蟑螂来源如何，也无论暴露剂量如何，铜和锌在海蟑螂的胞质和不溶性部分中大致均匀分布，这表明在整个条件范围内金属储存机制是相同的。采集后直接分析发现，杜拉斯湾的海蟑螂中MTLP的浓度高于米尔波特的海蟑螂，尽管在实验室中将其暴露于溶解的镉、铜或锌中，未能证明清洁场地或污染场地的海蟑螂在MTLP诱导方面存在差异。因此，类金属硫蛋白作为生物标志物的潜在作用不太可能，但这些蛋白质的周转率确实会因金属挑战增加而增加，从而使MTLP在金属解毒中发挥作用，这一点似乎仍然合理。
