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(W/EH044) Toxicity screening of newly synthesized substances and environmental samples using high-throughput-microplate assays with bacteria and algae: ring testing and automization. Eisentraeger, Adolf1, Reinke, Martin2, 1 2 ABSTRACT- In the recent years a lot of biological test systems have been transferred to the microplate scale with the aims of both reducing the costs and optimizing the biotests with respect to quality assurance and good laboratory practice. New fields of application of these microplate assays are given, since extremely low amounts of sample are needed and since test performance can be automized. E.g. newly synthesized chemical substances can be characterized ecotoxicologically, even if only low amounts of chemicals are available. Results of a laboratory intercomparison tests and a ring test with both standard tests in erlenmeyer flasks resp. cuvettes and microplate assays are presented. It is demonstrated, that the microplate assays fulfill the validity criteria of the existing standards. On the other hand, the deviations caused by different test set ups and their dependence on the physico-chemical characteristics of the chemicals or environmental samples are shown. A prototype of a High-Throughput-Algal-Growth-Inhibition-Test in accordance with the existing ISO-DIN-standards is presented, that is completely automized and allows to perform and evaluate algal and bacterial growth inhibition tests with photometric and fluorometric data acquistion. Light intensity and incubation temperature can be recorded and controlled on-line. If needed, other bioassays or liquid handling steps can be integrated. The technological approach of this flexible high throughput test system and first results are presented. Key words: Toxicity screening, high-throughput-testing, automization, ring testing |
