1. University of Osnabrück, Department of Biology and Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
2. University of Osnabrück, Department of Biology and Chemistry, Neurobiology section, Barbarastrasse 11, 49076 Osnabrück, Germany
3. Department of Biology, University of Utah, Salt Lake City, UT 84112, USA