Metals are widespread aquatic contaminants and affect aquatic wildlife in different ways. For instance, copper ions have been shown to specifically impair hair cells of the lateral line organ in fish. These cells are sensors of hydrodynamic flows helping the fish to orient, detect predators and prey and communicate with conspecifics. As a consequence, some behavioral responses, such as e.g. rheotaxis, a natural behavioral reaction of fish to orient counter-flow in order to hold a fixed position in a stream, are severely affected in copper-exposed fish.
AIM: The aim of this Master thesis is to investigate the effects of different metals on hair-cell mediated behavior of fish and to explore the mechanism by which these cells are specifically affected.
METHODs: To tackle this question, we are using zebrafish (Danio rerio) larvae, because of several reasons: genomic resources and genetic tools are available, their transparent larval stages enable different optical techniques and their small body size allows the continuous measurement of behavior with full control of the environment.
The impact of metals on hair cells will be elucidated from different angles: 1) Behavioral tests of metal-exposed zebrafish larvae will be performed, 2) hair cell structure and metal distribution will be investigated by different staining techniques followed by bright-field or confocal imaging and 3) the molecular basis of metal transport mechanisms will be studied by whole mount in situ hybridization in zebrafish larvae, which allows to localize gene expression of relevant transporters to specific tissues such as e.g. hair cells. Gene expression will form the basis for further loss-of-function experiments. Depending on the progression, the Master thesis could be extended with such functional tests.
Up to two Master thesis can be offered about this topic, and the project can be tailored to the candidate’s interests.
Suitable candidates for this project are expected to hold a BSc degree in biology, environmental sciences or a related discipline and to have experience in laboratory work.
For further information please contact Colette vom Berg (Colette.firstname.lastname@example.org) or Michael Burkard (Michael.Burkard@cluttereawag.ch) . This work will be performed at Eawag in the department of Environmental Toxicology in Dübendorf.