1. Department of SciencesRoma Tre University Roma Italy
2. Department of Molecular Biotechnology and Health SciencesUniversity of Torino Torino Italy
3. Department of MicrobiologyIWWR, Radboud University, Heyendaalseweg 135 Nijmegen AJ The Netherlands
4. Interdepartmental Laboratory for Electron MicroscopyRoma Tre University Roma Italy