apl. Prof. Thomas BraunbeckAquatic Ecology and Toxicology
The research focus of the Aquatic Ecology and Toxicology Group is on the identification of hazard and risk of environmental contaminants to aquatic biota and ecosystems. Most research projects are focused on sublethal health effects in fish and fish embryos, with the zebrafish (Danio rerio), the Japanese medaka (Oryzias latipes), the fathead minnow (Pimephales promelas) and the rainbow trout (Oncorhynchus mykiss) being the major experimental models organisms.
Originally, the group focused on cellular models such as primary hepatocytes isolated from rainbow trout or permanent fish cell lines such as RTG-2 and RTL-W1. In 1999, zebrafish vitellogenins were sequenced and developed as biomarkers for endocrine disruption; as such, these yolk protein precursors are now routinely used within the framework of compulsory OECD guidelines (OECD TG 229, TG 230, TG 234) for the detection of endocrine-active substances.
Since 2000, however, fish embryos were added as experimental tools, and since then cellular and embryo models are being developed in parallel as potential alternatives to conventional acute toxicity testing protocols such OECD test guidelines. In 2013, the Fish Embryo Toxicity Test developed by the Aquatox Group at Heidelberg was the first alternative ecotoxicological test method to be implemented into the OECD Testing Guideline scheme (OECD TG 236).
The toxicological endpoints routinely recorded include:
• bacterial toxicity
• endocrine effects
• teratogenic effects
• induction of biotransformation processes
• calcium oscillations
• histology and cytology
• integrative environmental assessment
• population-relevant changes (life-cycle experiments, two-generation experiments)
In addition to lab-based work, efforts are made to adapt these endpoints to make them suitable for use in limnological studies into the remediation of local river and lake systems.