1. Department of Biochemistry and Microbiology, Rutgers University 76 Lipman Dr New Brunswick NJ 08901, USA
2. Department of Environmental Chemistry and Microbiology, National Environmental Research Institute, Aarhus University Frederiksborgvej 399 DK-4000 Roskilde Denmark
3. Department of Biology, University of Ottawa 30-268 Marie Curie Ottawa, Ontario, K1N 6N5, Canada