DISTEVA, Dipartimento di Scienze della Terra, della Vita e dell'Ambiente, Università Carlo Bo di Urbino, Italy.
Aquat Toxicol. 2012 Sep 15;120-121:109-18. doi: 10.1016/j.aquatox.2012.04.015. Epub 2012 May 16.
Hexavalent chromium Cr(VI) is an important contaminant released from both domestic and industrial effluents, and represents the predominant chemical form of the metal in aquatic ecosystems. In the marine bivalve Mytilus galloprovincialis exposure to non-toxic, environmentally relevant concentrations of Cr(VI) was shown to modulate functional parameters and gene expression in both the digestive gland and hemocytes. In this work, the effects of exposure to Cr(VI) (0.1-1-10 μg L(-1) animal(-1) for 96 h) in mussel gills were investigated. Gill morphology and immunolocalization of GSH-transferase (GST), of components involved in cholinergic (AChE and ChAT), adrenergic (TH) and serotoninergic (5-HT(3) receptor) systems, regulating gill motility, were evaluated. Total glutathione content, activities of GSH-related enzymes (glutathione reductase - GSR, GST), of catalase, and of key glycolytic enzymes (phosphofructokinase - PFK and pyruvate kinase - PK) were determined. Moreover, mRNA expression of selected Mytilus genes (GST-π, metallothionein isoforms MT10 and MT20, HSP70 and 5-HT receptor) was assessed by RT-q-PCR. Cr(VI) exposure induced progressive changes in gill morphology and in immunoreactivity to components involved in neurotransmission that were particularly evident at the highest concentration tested, and associated with large metal accumulation. Cr(VI) increased the activities of GST and GSR, and total glutathione content to a different extent at different metal concentrations, this suggesting Cr(VI) detoxication/reduction at the site of metal entry. Cr(VI) exposure also increased the activity of glycolytic enzymes, indicating modulation of carbohydrate metabolism. Significant changes in transcription of different genes were observed. In particular, the mRNA level for the 5-HTR was increased, whereas both decreases and increases were observed for GST-π, MT10, MT20 and HSP70 mRNAs, showing sex- and concentration-related differences. The results demonstrate that Cr(VI) significantly affected functional and molecular parameters in mussel gills, and indicate that this tissue represents the major target of exposure to environmentally relevant concentrations of the metal.
六价铬 Cr(VI) 是一种重要的污染物，来自于家庭和工业废水，是水生生态系统中金属的主要化学形态。在海洋双壳类贻贝 Mytilus galloprovincialis 中，暴露于无毒、环境相关浓度的 Cr(VI) 会调节消化腺和血细胞中的功能参数和基因表达。在这项工作中，研究了 Cr(VI)（0.1-1-10 μg L(-1) 动物(-1) ，96 h）在贻贝鳃中的暴露对贻贝鳃的影响。评估了鳃形态和谷胱甘肽转移酶 (GST)、涉及胆碱能 (AChE 和 ChAT)、肾上腺素能 (TH) 和 5-羟色胺能 (5-HT(3)受体) 系统的成分的免疫定位，这些成分调节鳃的运动。测定了总谷胱甘肽含量、GSH 相关酶（谷胱甘肽还原酶 - GSR、GST）、过氧化氢酶和关键糖酵解酶（磷酸果糖激酶 - PFK 和丙酮酸激酶 - PK）的活性。此外，通过 RT-qPCR 评估了选定的贻贝基因 (GST-π、金属硫蛋白同工型 MT10 和 MT20、HSP70 和 5-HT 受体) 的 mRNA 表达。Cr(VI) 暴露诱导鳃形态和参与神经传递的成分的免疫反应发生进行性变化，在测试的最高浓度下尤为明显，并且与大量金属积累有关。Cr(VI) 以不同的程度在不同的金属浓度下增加 GST 和 GSR 的活性以及总谷胱甘肽含量，这表明 Cr(VI) 在金属进入部位进行解毒/还原。Cr(VI) 暴露还增加了糖酵解酶的活性，表明碳水化合物代谢的调节。不同基因的转录发生了显著变化。特别是，5-HTR 的 mRNA 水平增加，而 GST-π、MT10、MT20 和 HSP70 的 mRNA 水平则下降和增加，表现出性别和浓度相关的差异。结果表明，Cr(VI) 显著影响贻贝鳃的功能和分子参数，并表明该组织是暴露于环境相关浓度金属的主要靶标。
