Fasulo S, Mauceri A, Giannetto A, Maisano M, Bianchi N, Parrino V
Department of Animal Biology and Marine Ecology, University of Messina, Messina, Italy.
Aquat Toxicol. 2008 Jun 2;88(1):62-8. doi: 10.1016/j.aquatox.2008.03.009. Epub 2008 Mar 21.
Metallothioneins (MTs), metal-inducible proteins, are crucial proteins for the regulation of essential metals, and are transcriptionally induced in all organisms by certain heavy metals, oxidative stress and inflammation. The gills represent an organ of uptake and loss of metals in which different mechanisms are present controlling the functions directly involved in the maintenance of homeostasis. In this study, the morphological and histomorphological aspects of branchial epithelium in Mytilus galloprovincialis from polluted environment (Faro swamp, Messina, Italy) have been investigated. The reverse transcriptase-polymerase chain reaction (PCR) has been used to isolate complementary DNA of both MT isoforms present from RNA extracted from mussel gills. The respective mRNAs on histological sections have been visualized by in situ hybridization. These methods showed that MT-10 mRNA is expressed at the basal level. In contrast, the MT-20 expression level was very low under basal conditions, while its mRNA increased dramatically in individuals collected in Faro. The presence of acid mucocytes and MTs in the gills may be considered a further defensive mechanism also related to the significantly higher concentration of Cd, Pb and Cr found in gills of M. galloprovincialis from Faro than specimens from the reference site (Goro). The results obtained show that, in stressed mussels, the defensive processes increase to maintain the normal functions of the organs more exposed to the action of polluted substances.
金属硫蛋白（MTs）是金属诱导蛋白，是调节必需金属的关键蛋白，在所有生物体中，某些重金属、氧化应激和炎症可诱导其转录。鳃是金属摄取和流失的器官，其中存在不同机制来控制直接参与维持体内平衡的功能。在本研究中，对来自污染环境（意大利墨西拿法罗沼泽）的地中海贻贝鳃上皮的形态学和组织形态学方面进行了研究。逆转录聚合酶链反应（PCR）已用于从贻贝鳃中提取的RNA中分离出两种MT亚型的互补DNA。通过原位杂交在组织切片上观察各自的mRNA。这些方法表明MT-10 mRNA在基础水平表达。相比之下，MT-20在基础条件下的表达水平非常低，而其mRNA在法罗采集的个体中显著增加。鳃中酸性黏液细胞和MTs的存在可能被认为是一种进一步的防御机制，这也与法罗的地中海贻贝鳃中镉、铅和铬的浓度显著高于参考地点（戈罗）的标本有关。获得的结果表明，在受到应激的贻贝中，防御过程会增强，以维持更易受到污染物质作用的器官的正常功能。
