1. Antibiotics Laboratory, RIKEN, Hirosawa, Wako, Saitama 351-0198, Japan
2. Faculty of Science and Engineering, Tokyo Denki University, Hatoyama, Saitama 350-0394, Japan
3. Department of Life Science and Research Center for Life Science, Rikkyo University, Nishi-Ikebukuro, Toshima-ku, Tokyo 171–8501, Japan
4. Kunming Institute of Botany, Chinese Academy of Science, Kunming 650204, China
5. Department of Chemistry and Research Center for Smart Molecules, Rikkyo University, Nishi-Ikebukuro, Toshima-ku, Tokyo 171–8501, Japan