1. Department of Applied Bioorganic Chemistry, Gifu University, 1‐1 Yanagido, Gifu‐shi, Gifu 501‐1193 (Japan), Fax: (+81) 58‐293‐3452
2. Department of Applied Bioorganic Chemistry, Institute for Integrated Cell‐Material Sciences (WPI program), Kyoto University, Yoshida Ushinomiya‐cho, Sakyo‐ku, Kyoto 606‐8501 (Japan)
3. Departments of Microbiology & Medicine, National University of Singapore, 5 Science Drive 2, Blk MD4A, Level 5, Singapore 117597