Short description
(English)
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In this project a screening tool for the ecotoxicological hazard assessment of porous media and other aqueous samples shall be developed. The test system can be used for the cost-efficient and fast investigation of the potentially toxic samples. The test will be based on an already existing teratogenesis assay using zebrafish eggs and will be expanded with molecular tools. Beside the potential of acute toxicity and teratogenesis further chronic toxic effects, such as endocrine disruption and genotoxicity and can be detected in the genetically modified zebrafish eggs within 48 hours by simple microscopic observations. The gained knowledge about the mode of toxic action may render a predictive transfer of the results to other species possible.
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Partners and International Organizations
(English)
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AT, BE, BG, HR, CY, CZ, DK, FR, DE, EL, HU, IE, IL, IT, LT, MT, NL, NO, SK, ES, CH, UK
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Abstract
(English)
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Testing of molecular effects in ecotoxicology usually is performed in unicellular organisms or cell cultures. However, pollutant-uptake kinetics, partitioning, as well as metabolism, cell type-specific transcription and developmental stages are absent in such test systems and can strongly influence toxic effects observed in higher organisms. A test system that on the one hand permits detection and integration of (several) molecular effects in higher organisms and on the other hand is still relatively easy and quick to perform is highly interesting for ecotoxicological studies. Using zebrafish embryos/larvae, we have developed such a test system. Freshly fertilized zebrafish eggs are exposed in groups of 50 during 5 days in 50ml sample volume. Total RNA is isolated, reverse transcribed and semiquantitative real-time PCR on targeted genes is then carried out. A first module of this test system is the detection of estrogenic effects, induced by (xeno-)estrogens. Based on gene array data, we have selected the vitellogenin1 gene (vtg1) as target gene for xenoestrogen exposures. Vitellogenin1 is clearly induced by the model compound Ethinylestradiol (EE2). This is much faster compared to two weeks exposure in adult fish. Significant induction can be measured already at three days after fertilization at 100ng/L EE2. Currently we are further developing the system for testing other (and putative) xenoestrogens. In principle, the test is also applicable for environmental samples. By identifying further genes that make suitable biomarkers for other toxic effects, such as androgenicity, thyroidicity, immunotoxicity and DNA mutagenicity, we plan to expand the scope of this test system, thus making it a fairly quick and dense multi-tox screening method for environmental samples and single compounds.
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