1. Department
of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
2. Institute
of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Academician Georgi Bonchev Street, Bl. 9, 1113 Sofia, Bulgaria
3. Institute
of Pharmacy, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
4. The
Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 26 Academician Georgi Bonchev Street, 1113 Sofia, Bulgaria