1. Institute of Pharmacology and Toxicology, University Hospital/RWTH Aachen, Aachen, Germany.
2. Biofilm Centre, University of Duisburg-Essen, Essen, Germany.
3. Research Group Astrobiology, Radiation Biology Department, Institute of Aerospace Medicine, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Cologne, Germany.