Podrug Marijana, Raspor Biserka, Erk Marijana, Dragun Zrinka
Ruder Bosković Institute, Division for Marine and Environmental Research, Zagreb, Croatia.
Chemosphere. 2009 May;75(7):843-9. doi: 10.1016/j.chemosphere.2009.01.079. Epub 2009 Mar 4.
Indigenous specimens of European chub were caught at five sites in Sava River during two successive non-reproductive periods and used as bioindicator organisms for the assessment of metal accumulation. Liver was selected as a target organ and the metal concentrations (Zn, Cu, Fe, Mn, and Cd) were determined in two fractions of hepatic cytosol, namely in untreated (S50) and heat-treated (HT S50) fraction. In addition, the concentrations of total cytosolic proteins were measured in untreated (S50) fractions, whereas the concentrations of specific metal-binding proteins, i.e. metallothioneins, were determined in the heat-treated fractions. Concentrations of Zn and Fe were significantly higher in the untreated compared to heat-treated cytosol, because these metals are associated to the heat-sensitive metalloenzyme and high molecular mass proteins. On the contrary, Cu, Mn and Cd were predominantly present in the heat-treated cytosol, which contains metallothioneins. In both fractions of hepatic cytosol, nonessential metal Cd showed statistically significant increase from the upstream sites (median 5 ng mL(-1)) toward the downstream site Jasenovac (median 11 ng mL(-1)). The metallothionein concentrations, on the contrary, did not differ between sites, probably due to low dissolved and labile concentrations of metals known as metallothionein inducers (Zn, Cu, and especially Cd) in river water. Therefore, Cd concentrations in hepatic cytosol of European chub can be recommended as an early-warning marker of fish chronic exposure to Cd from combined sources, water and ingested food.
在萨瓦河的五个地点，于两个连续的非繁殖期捕获了欧洲鲢的本地样本，并将其用作生物指示生物来评估金属积累情况。选择肝脏作为靶器官，测定了肝细胞溶质的两个组分中金属（锌、铜、铁、锰和镉）的浓度，即未处理组分（S50）和热处理组分（HT S50）。此外，测定了未处理组分（S50）中总细胞溶质蛋白的浓度，而在热处理组分中测定了特定金属结合蛋白即金属硫蛋白的浓度。与热处理后的细胞溶质相比，未处理细胞溶质中锌和铁的浓度显著更高，因为这些金属与热敏感金属酶和高分子量蛋白质相关。相反，铜、锰和镉主要存在于含有金属硫蛋白的热处理细胞溶质中。在肝细胞溶质的两个组分中，非必需金属镉从上游地点（中位数为5 ng mL(-1)）到下游地点亚塞诺瓦茨（中位数为11 ng mL(-1)）呈现出统计学上显著的增加。相反，金属硫蛋白的浓度在各地点之间没有差异，这可能是由于河水中作为金属硫蛋白诱导剂的金属（锌、铜，尤其是镉）的溶解浓度和不稳定浓度较低。因此，欧洲鲢肝细胞溶质中的镉浓度可被推荐作为鱼类长期暴露于来自水和摄入食物的联合镉源的早期预警指标。
