1. Hans Knoell Institute for Natural Products Research, Beutenbergstrasse I la, D-07745 Jena, Germany
2. Department of Bacteriology and Immunology, Haartman Institute, Haartmaninkatu 3, University of Helsinki, FIN-00290 Helsinki, Finland
3. Institute of Medical Microbiology, Frankfurt University Hospital, Paul-Ehrlich-Str. 40, D-60596 Frankfurt, Germany
4. Mario Negri Institute for Pharmacological Research, Bergamo, Italy