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Ann-Kathrin Lörracher


Centre for Organismal Studies

Abteilung Tierphysiologie / Entwicklungsbiologie

Im Neuenheimer Feld 504

Phone: +49-(0)6221/54-5629

Fax:: +49-(0)6221/54-6162

e-Mail: Loerracher@stud.uni-heidelberg.de





Dissertation title:

Biotransformation and bioactivation capacities in early life stages of zebrafish

Short description:

Zebrafish (Danio rerio) early life stages (<120 hpf) have become increasingly used alternative models for toxicity testing and (eco-) toxicological screening. In 2013, the fish embryo acute toxicity (FET) test with zebrafish was adopted by OECD as test guideline 236.

Major objections to the use of the FET with the zebrafish have mainly based on the assumption of limited biotransformation capacity in early life stages. Doubts have been expressed concerning the comparability of metabolic capacity between early juvenile and adult life stages of zebrafish. In fact, a limited biotransformation or bioactivation capacity could lead to underestimations of toxic or teratogenic potency of a xenobiotic, which would be bioactivated in other life stages. It seems reasonable to assume at least qualitatively appropriate biotransformation capacities. As a consequence, in order to strengthen the acceptance of the fish embryo test, it is essential to better understand the metabolic capacities of zebrafish embryos throughout development.

The thesis will focus on the biotransformation and bioactivation capacity in early life stages of zebrafish. The spectrum of methods includes classical fish embryo toxicity testing with well-known pro-teratogens and their metabolites, in vivo fluorescence assays (e.g. EROD assay), as well as measurement of CYP induction (quantitative real-time PCR).

This project is funded by the Ministry of Science, Research and the Arts of the State of Baden-Württemberg.