Universität Heidelberg

Given that the ultimate goal of ecotoxicology is the identification of effects at the population and ecosystem levels, microbial communities were picked for reasons of their supreme importance in the environment. Two microbial communities (intestinal microbiomes and environmental microbial biofilms) will be investigated with respect to effects by the test substances (cf. WPs 1 and 2). The intestinal biofilm population shifts may be responsible for the health status of the aquatic organisms, whereas
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As an intermediate stage of complexity, fish embryos will be used as a tool to mediate the transfer of data compiled at the molecular and cellular levels (WPs 3 and 4) to intact, fully developed fish (WP 6). To this end, similar endpoints as in WP 4 will be recorded in modified zebrafish embryo assays [85]. In addition, extension of the test duration will allow adding of teratogenic effects to the list of endpoints.

The purpose of WP 4 is to provide a set of toxicological base data on the test substances at the mo-lecular and cellular levels. The focus will not be restricted to basic acute toxicity, but will also cover specific endpoints such as interaction with DNA and DNA damage, the induction of cytochrome P450 as well as the response to glucocorticoid stress hormones and metabolic signaling by glucose. With respect to the selection of test compounds, WP 4 depends on the outcome of WPs 1 and 2.

WP 2 will address metabolites and transformation products (TPs) of compounds selected in WP 1. These will be generated and identified by means of electrochemical synthesis mimicking mainly Phase I metabolism and mass spectrometric detection. The mixture of metabolites and TPs will be used for ligand screening with nuclear receptors (WP 3) using the analytical methodology devel-oped as well as for further toxicity screening for effects on cells (WP 4) and in biota (WPs 5 and 6).

This WP aims at understanding the awareness of the different actor groups to the impact of two types of substances on aquatic ecosystems in terms of biodiversity and human health: pharmaceu-ticals and food additives. The WP brings together both quantitative and qualitative methods for gen-erating and analyzing data. Each research step will be informed by the findings of the science teams and make an effort to integrate as much of the knowledge produced with regard to toxicolog-ical and ecological
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