1. Department of Food and Environmental Sciences, Division
of Microbiology and Biotechnology, University of Helsinki, Viikinkaari
9, Helsinki 00014, Finland
2. Center for Microbial Ecology, Department
of Civil and Environmental Engineering, Michigan State University, East
Lansing, Michigan 48824-1325, United States
3. Department of Biosciences, University of Helsinki, Viikinkaari 1, Helsinki 00014, Finland