Department of Integrative Ecophysiology, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research , Am Handelshafen 12, 27570 Bremerhaven, Germany.
Faculty of Biology and Chemistry, University of Bremen , Leobener Straße, 28359 Bremen, Germany.
Environ Sci Technol. 2017 Jun 20;51(12):7208-7218. doi: 10.1021/acs.est.6b06613. Epub 2017 Jun 1.
Eulimnogammarus cyaneus and Eulimnogammarus verrucosus, closely related amphipod species endemic to Lake Baikal, differ with respect to body size (10- to 50-fold lower fresh weights of E. cyaneus) and cellular stress response (CSR) capacity, potentially causing species-related differences in uptake, internal sequestration, and toxic sensitivity to waterborne cadmium (Cd). We found that, compared to E. verrucosus, Cd uptake rates, related to a given exposure concentration, were higher, and lethal concentrations (50%; LC50) were 2.3-fold lower in E. cyaneus (4 weeks exposure; 6 °C). Upon exposures to species-specific subacutely toxic Cd concentrations (nominal LC1; E. cyaneus: 18 nM (2.0 μg L); E. verrucosus: 115 nM (12.9 μg L); 4 weeks exposure; 6 °C), Cd amounts in metal sensitive tissue fractions (MSF), in relation to fresh weight, were similar in both species (E. cyaneus: 0.25 ± 0.06 μg g; E. verrucosus: 0.26 ± 0.07 μg g), whereas relative Cd amounts in the biologically detoxified heat stable protein fraction were 35% higher in E. cyaneus. Despite different potencies in detoxifying Cd, body size appears to mainly explain species-related differences in Cd uptake and sensitivities. When exposed to Cd at LC1 over 4 weeks, only E. verrucosus continuously showed 15-36% reduced oxygen consumption rates indicating metabolic depression and pointing to particular sensitivity of E. verrucosus to persisting low-level toxicant pressure.
西伯利亚螯虾和红斑沼虾是两种亲缘关系密切的特有贝加尔湖端足目甲壳动物，在体型大小（西伯利亚螯虾的湿重比红斑沼虾低 10-50 倍）和细胞应激反应（CSR）能力方面存在差异，这可能导致它们在摄入、体内隔离以及对水基镉（Cd）的毒性敏感性方面存在种间差异。我们发现，与红斑沼虾相比，在相同暴露浓度下，西伯利亚螯虾的 Cd 吸收速率更高，LC50 低 2.3 倍（4 周暴露；6°C）。在暴露于特定的亚急性毒性 Cd 浓度（名义 LC1；西伯利亚螯虾：18 nM（2.0 μg/L）；红斑沼虾：115 nM（12.9 μg/L）；4 周暴露；6°C）下，与鲜重相比，两种虾金属敏感组织（MSF）中的 Cd 含量相似（西伯利亚螯虾：0.25±0.06 μg/g；红斑沼虾：0.26±0.07 μg/g），而生物解毒的热稳定蛋白部分的相对 Cd 含量在西伯利亚螯虾中则高出 35%。尽管在解毒 Cd 方面的能力不同，但体型似乎主要解释了 Cd 吸收和敏感性方面的种间差异。当在 LC1 下暴露于 Cd 超过 4 周时，只有红斑沼虾的耗氧率持续降低 15-36%，表明其代谢受到抑制，并指出红斑沼虾对持续存在的低水平毒性压力特别敏感。
