1. Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 00 Prague 4, Czech Republic
2. First Faculty of Medicine, Charles University, Prague, Czech Republic
3. Institute of Molecular Genetics of the Czech Academy of Sciences, Microscopy Centre, Electron Microscopy Core Facility, Videnska 1083, 142 20 Prague 4, Czech Republic
4. Institute for Environmental Studies, Faculty of Science, Charles University, Benatska 2, 128 01 Prague 2, Czech Republic
5. Institute of Hydrodynamics of the Czech Academy of Sciences, Pod Patankou 30/5, 166 12, Prague 6, Czech Republic