1. Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, Germany
2. Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
3. Biozentrum, University of Basel, Basel, Switzerland
4. Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
5. Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, USA