1. Department of Virology II; National Institute of Infectious Diseases; 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011
2. Institute of Organic Chemistry with Centre of Phytochemistry; Bulgarian Academy of Sciences; Academician Georgi Bonchev Street, Bl.9-1113
3. Stephan Angeloff Institute of Microbiology; Bulgarian Academy of Sciences, 26 Academician Georgi Bonchev Street; BG-1113 Sofia Bulgaria