Vogt Christian, Nowak Carsten, Diogo Joao Barateiro, Oetken Matthias, Schwenk Klaus, Oehlmann Jörg
J.W. Goethe University, Institute of Ecology, Evolution and Diversity, Department Aquatic Ecotoxicology, Siesmayerstrasse 70, D-60323 Frankfurt am Main, Germany.
Chemosphere. 2007 May;67(11):2192-200. doi: 10.1016/j.chemosphere.2006.12.025. Epub 2007 Jan 26.
While toxicological data are available for numerous chemicals from standard tests, little is known on effects of pollutants over several generations or regarding chronic effects of chemicals on genetic diversity. Within the experiments, effects of the model pollutant tributyltin (TBT) were investigated over eleven generations at a sublethal TBT concentration of 4.46 microg as Sn kg-1 sediment dw on life-cycle parameters and genetic variability of Chironomus riparius. Moreover, the adaptation potential towards TBT was determined. This experimental design enables the identification of TBT effects on life-cycle parameters and the determination of a potential extinction risk caused by chronic exposure. Furthermore, effects on the genetic structure can be determined, which are not predictable based solely on knowledge of the toxic mode of action of the chemical. Genetic variety was determined via microsatellite analysis, measuring individual length differences of highly variable satellite DNA fragments. For the identification of changes in tolerances towards the stressor, acute and chronic toxicity experiments were conducted. During the multi-generation study, significant effects on development and reproduction were determined. For some generations, the emergence was significantly (p<0.05) delayed under TBT exposure. Reproduction seems to be a sensitive parameter as well, whereby females laid significantly larger egg masses (p<0.05) in the latter generations. TBT did not affect the population growth rate nor the genetic variability, while clear deviations from the Hardy-Weinberg equilibrium appeared. The study also provides strong evidence for the acquirement of a higher tolerance towards the stressor in the TBT-exposed group.
虽然通过标准测试可获得众多化学物质的毒理学数据，但对于污染物在多代中的影响或化学物质对遗传多样性的慢性影响却知之甚少。在实验中，研究了模型污染物三丁基锡（TBT）在4.46微克锡/千克沉积物干重的亚致死浓度下，对摇蚊十一个世代的生命周期参数和遗传变异性的影响。此外，还确定了对TBT的适应潜力。这种实验设计能够识别TBT对生命周期参数的影响，并确定慢性暴露导致的潜在灭绝风险。此外，还可以确定对遗传结构的影响，而仅根据化学物质的毒性作用方式的知识是无法预测这些影响的。通过微卫星分析确定遗传多样性，测量高度可变的卫星DNA片段的个体长度差异。为了识别对压力源耐受性的变化，进行了急性和慢性毒性实验。在多代研究中，确定了对发育和繁殖的显著影响。在某些世代中，TBT暴露下羽化明显延迟（p<0.05）。繁殖似乎也是一个敏感参数，在后几代中，雌性产卵量显著更大（p<0.05）。TBT没有影响种群增长率和遗传变异性，但出现了明显偏离哈迪-温伯格平衡的情况。该研究还为TBT暴露组对压力源获得更高耐受性提供了有力证据。
