1. Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9
2. Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Box 5003, 1432, Ås, Norway/Microbial Evolution Research Group, Department of Biology, University of Oslo, PO Box 1066 Blindern, N-0316 Oslo, Norway
3. Medicine/Dentistry Electron Microscopy Unit, University of Alberta, Edmonton, Alberta T6G 2N8