Díaz Silvia, Martín-González Ana, Carlos Gutiérrez Juan
Departamento de Microbiología-III, Facultad de Biología, C/. José Antonio Novais 2, Universidad Complutense (UCM), Madrid 28040, Spain.
Environ Int. 2006 Aug;32(6):711-7. doi: 10.1016/j.envint.2006.03.004. Epub 2006 May 2.
Laboratory toxicity tests, using ciliated protozoa, are scarce and they have been carried out usually with freshwater species. In this study, we have analysed the acute cytotoxicity of Cd, Zn and Cu in five different strains of very common soil ciliate species (Colpoda steinii, Colpoda inflata and Cyrtolophosis elongata), which were isolated from very different soil samples (polluted or not with heavy metals). Soil ciliates are quite resistant to heavy metals pollution with regard to ciliates from other habitats. The toxicity sequence was Cd>Cu>>Zn. Results from Cd+Zn mixtures indicated that Cd cytotoxicity decreases in the presence of low or moderate Zn concentrations. A broad heavy metal resistance level diversity exists among isolates of colpodid ciliates and it is seen to be a genetic feature rather than a habitat dependence. Bioaccumulation is seen to be the main mechanism involved in the metal resistance, except for Cu. For the first time in ciliates, a fluorescent method has been applied to detect Zn intracellular deposits. This methodology might be an useful tool for monitoring heavy metal pollution in soils.
使用纤毛原生动物进行的实验室毒性测试很少，而且通常是针对淡水物种开展的。在本研究中，我们分析了镉、锌和铜对五种非常常见的土壤纤毛虫（斯坦尼肾形虫、膨胀肾形虫和细长环毛虫）不同菌株的急性细胞毒性，这些菌株是从截然不同的土壤样本（受重金属污染或未受污染）中分离出来的。与来自其他生境的纤毛虫相比，土壤纤毛虫对重金属污染具有相当强的抗性。毒性顺序为镉>铜>>锌。镉与锌混合物的结果表明，在低浓度或中等浓度锌存在的情况下，镉的细胞毒性会降低。肾形虫纤毛虫的分离株之间存在广泛的重金属抗性水平差异，这被视为一种遗传特征而非对生境的依赖。除了铜之外，生物积累被视为金属抗性的主要机制。在纤毛虫中首次应用荧光方法检测细胞内锌沉积物。这种方法可能是监测土壤中重金属污染的有用工具。
