1. Department of Biochemistry and Biotechnology, Laboratory of Bioorganic Chemistry, University of Thessaly, Viopolis, Larissa, Greece
2. Institute of Biology, National Centre for Scientific Research ‘‘Demokritos’’, 15310 Ag. Paraskevi, Athens, Greece
3. Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium