Vahl H H, Karbe L, Westendorf J
Department of Toxicology, Medical School, University of Hamburg, Germany.
Mutat Res. 1997 Nov 27;394(1-3):81-93. doi: 10.1016/s1383-5718(97)00129-0.
This study evaluates the applicability of three bacterial short-term genotoxicity test systems to aquatic suspended particulate matter of the Elbe river. This material was sampled in sedimentation vessels after deposition periods of one month. It was extracted in a Soxhlet apparatus with toluene and methanol. Aqueous elutriates were prepared additionally. A solid phase method was developed that enables to incubate bacteria in contact with the particulate material. The test battery consists of two mutagenicity assays (the Ames-test and the Ara-test) and an SOS induction assay (the umu-test). Both mutagenicity assays came to nearly the same assessment of the samples of particulate matter of the Elbe. The quantitative response, however, was higher in the Ara-test. The particulate river material generally induced lower genotoxic potencies in the umu-test than in the mutagenicity assays. This lead to a completely different outcome of the umu-test; 29 out of 35 mutagenic samples were not SOS inducing. No quantitative or rank correlations between the concentrations of anthropogenic contaminants (PAHs, chlorinated hydrocarbons and metals) and the observed effects could be established on a 90% confidence limit. However, there is obvious correspondence between more contaminated regions of the river system and mutagenic effects (Ames- and Ara-test) in the samples from this region, as well as correspondence between low contaminated regions and the absence of mutagenicity. For this reason, the mutagenicity assays appear more favourable to describe the anthropogenic contamination with genotoxins in complex mixtures than the umu-test. The authors recommend the Ara-test for a first genotoxicity screening of complex environmental mixtures. This forward mutagenicity assay is advantageous due to higher effects and lower costs compared to the Ames-test. The development and use of a solid phase version of Ames- and Ara-test revealed the occurrence of a major part of particle-bound mutagens. The hydrophobic nature of these mutagens was also confirmed by the gradually decreasing effects with decreasing lipophilicity of the solvents. The results suggest that the solid phase test and the use of extracts complement each other in detecting mutagens of different lipophilicity. Both versions should be used in order to include a broad variety of compounds.
本研究评估了三种细菌短期遗传毒性测试系统对易北河水中悬浮颗粒物的适用性。该物质在沉积一个月后于沉降容器中取样。用甲苯和甲醇在索氏提取器中进行提取。另外还制备了水相洗脱液。开发了一种固相方法，使细菌能够与颗粒物质接触进行培养。测试组合包括两种致突变性试验（艾姆斯试验和Ara试验）和一种SOS诱导试验（umu试验）。两种致突变性试验对易北河颗粒物样品的评估几乎相同。然而，Ara试验中的定量反应更高。河流颗粒物在umu试验中一般诱导的遗传毒性效力低于致突变性试验。这导致umu试验结果完全不同；35个致突变样品中有29个未诱导SOS。在90%置信限下，无法确定人为污染物（多环芳烃、氯代烃和金属）浓度与观察到的效应之间的定量或等级相关性。然而，河流系统中污染更严重的区域与该区域样品中的致突变效应（艾姆斯试验和Ara试验）之间存在明显对应关系，污染较轻的区域与无致突变性之间也存在对应关系。因此，与umu试验相比，致突变性试验似乎更有利于描述复杂混合物中基因毒素的人为污染。作者推荐Ara试验用于复杂环境混合物的首次遗传毒性筛选。这种正向致突变性试验由于与艾姆斯试验相比效果更高且成本更低而具有优势。艾姆斯试验和Ara试验固相版本的开发和使用揭示了大部分颗粒结合诱变剂的存在。这些诱变剂的疏水性也通过随着溶剂亲脂性降低效应逐渐减弱得到证实。结果表明，固相试验和提取物的使用在检测不同亲脂性的诱变剂方面相互补充。两种版本都应使用，以便涵盖多种化合物。
