[1] Max Planck Inst Chem Ecol, Dept Biochem, D-07745 Jena, Germany
[2] Univ Michigan, Dept Mol Cellular & Dev Biol, Ann Arbor, MI 48109 USA
[3] Ionicon Analyt GmbH, A-6020 Innsbruck, Austria
[4] Leopold Franzens Univ Innsbruck, Inst Ionenphys & Angewandte Phys, Innsbruck, Austria