1. Department of Microbiology, Max Planck Institute for Marine Microbiology, D-28359 Bremen, Germany
2. Center for EM (NWF III, Institute for Anatomy), University of Regensburg, D-93053 Regensburg, Germany
3. Department for Marine Microbiology, UFT, University of Bremen, D-28359 Bremen, Germany
4. Marine Microbiology Group, Institut Mediterrani d'Estudis Avançats (CSIC-UIB), E-07190 Esporles, Illes Balears, Spain