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(30-03) Evaluation of a battery of prokaryotic stress gene assays for environmental toxicity screening purposes. Dardenne, Freddy*,1,2, Vlaeminck, Andrea1, Willems, Kris1,2, Decoen, Wim1, Blust, Ronny1, 1 Department of Biology, Antwerp, Belgium, Belgium2 Food and Environmental Toxicology, Sint-Katelijne-Waver, Belgium, Belgium ABSTRACT- Thousands of environmental pollutants are continuously released to the environment and new substances are introduced on a permanent basis. To determine the potential hazards of the individual compounds and evaluate the toxicity of effluents and other sources of pollution different types of biological tests have been developed. Most of the currently used ecotoxicological test procedures use survival, growth inhibition or related processes as end-point. These assays can reveal whether or not a substance or effluent is potentially toxic, but do not provide information concerning the nature or mode of action of the toxicants present. Recent developments in ecotoxicological testing involves the use of in vitro cellular systems that generate differentiated responses providing information on the toxic action of the compounds or mixtures tested. In the present study a battery of E.coli based stress gene assays, the Protox gene profiling assay, was used to determine the effect of existing and well characterised toxic compounds and mixtures of these on stress gene activation. The assay detects a variety of transcriptional responses in E.coli through specific constructs that report the activity of certain genes in a quantitative manner. The bacterial promoters included in this assay are fused to the lacZ structural gene and cover a wide range of responses including osmotic shock, oxidative stress and genotoxicity. The potential of this test battery for incorporation in ecotoxicological test programs was evaluated and the results compared with existing tests used for regulatory purposes. A comparison was made between the response profiles obtained with single toxicants and more or less complex mixtures to explore the potential of the assays for use in regulatory and effluent toxicity screening. Key words: Stress gene assay, In vitro toxicology, gene expression, E. coli |
