1. Department of Proteomics, School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Center, SE-106 91 Stockholm, Sweden
2. Department of Molecular Evolution, Evolutionary Biology Center, Uppsala University, SE-752 36 Uppsala, Sweden
3. Department of Bacteriology, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden
4. The Mycoplasma Group, Veterinary Laboratories Agency (VLA), Addlestone, Surrey KT15 3NB, UK