1. Marine Sciences Research Center, State University of New York at Stony Brook, Stony Brook, New York 11794-5000
2. Institut de Génétique et Microbiologie, CNRS UMR 8621, Université Paris Sud, Bâtiment 400, 91405 Orsay Cedex, France
3. Microbiology and Genetics, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium