1. Max Planck Institute for Terrestrial Microbiology Karl-von-Frisch-Straße 10 35043 Marburg Germany
2. Laboratory of Inorganic Synthesis and Catalysis Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne (EPFL) ISIC-LSCI, BCH 3305 1015 Lausanne Switzerland
3. Department of Plant and Microbial Biology University of Minnesota Twin Cities St. Paul, MN USA