Dang Fei, Zhong Huan, Wang Wen-Xiong
AMCE and Department of Biology, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong.
Aquat Toxicol. 2009 Sep 14;94(3):238-44. doi: 10.1016/j.aquatox.2009.07.011. Epub 2009 Jul 22.
The uptake kinetics and regulation of copper in a marine predatory fish, the black sea bream Acanthopagrus schlegeli after acclimation to waterborne Cu were examined, using radiotracer techniques. The dissolved Cu uptake followed a linear pattern during the time of exposure, and the calculated uptake rate constant was 6.24 L kg(-1) day(-1). The efflux rate constant was 0.091 day(-1) following dietary uptake of Cu, and the dietary assimilation efficiency (AE) of Cu varied between 1.7% and 10.9% after the fish were fed with three types of prey (oysters, clams and brine shrimp). After the fish were acclimated at a nominal concentration of 50 microg Cu L(-1) for 14 days, the Cu uptake rate and efflux rate constant did not change significantly, but the Cu body concentrations and metallothionein (MT) concentrations in fish tissues increased significantly. Subcellular Cu distributions were also modified. Significant MT induction was observed in response to increased Cu tissue concentrations, indicating that MT rather than the uptake kinetics may play a primary role in Cu regulation during waterborne Cu acclimation in this marine fish. Moreover, the high Cu efflux may also be important in Cu regulation during long-term exposure. Our modeling calculations indicated that dietary uptake was likely to be the main route for Cu bioaccumulation in the fish, and the relative contribution of waterborne and dietary uptake depended on the bioconcentration factor (BCF) of the prey and ingestion rate of fish.
利用放射性示踪技术，研究了海洋掠食性鱼类黑鲷（Acanthopagrus schlegeli）在适应水体铜后对铜的吸收动力学及调节机制。在暴露期间，溶解态铜的吸收呈线性模式，计算得出的吸收速率常数为6.24 L kg⁻¹ day⁻¹。通过饮食摄取铜后，排出速率常数为0.091 day⁻¹，在用三种类型的猎物（牡蛎、蛤蜊和卤虫）喂养鱼类后，铜的饮食同化效率（AE）在1.7%至10.9%之间变化。在鱼类于50 μg Cu L⁻¹的标称浓度下适应14天后，铜的吸收速率和排出速率常数没有显著变化，但鱼组织中的铜体浓度和金属硫蛋白（MT）浓度显著增加。亚细胞铜分布也发生了改变。观察到随着铜组织浓度的增加，MT有显著诱导，这表明在这种海洋鱼类适应水体铜的过程中，MT而非吸收动力学可能在铜调节中起主要作用。此外，高铜排出在长期暴露期间的铜调节中也可能很重要。我们的模型计算表明，饮食摄取可能是鱼类铜生物积累的主要途径，水体和饮食摄取的相对贡献取决于猎物的生物浓缩因子（BCF）和鱼类的摄食率。
