1. Ludwig Maximillians University Munich; Dept. Biology I, LMU Biozentrum; 82152 Martinsried Germany
2. University of Stuttgart; Dept. of Material Science, Heisenbergstraße 3; 70569 Stuttgart Germany
3. Division of Microbiology, Faculty of Biology; Ludwig Maximilians University of Munich; Großhaderner Strasse 2-4 82152 Martinsried Germany