1. Ōmura Satoshi Memorial Institute, Kitasato University, Minato-ku, Tokyo 108-8641, Japan
2. Graduate School of Infection Control Sciences, Kitasato University, Minato-ku, Tokyo 108-8641, Japan
3. Laboratory of Microbiology, School of Pharmacy, Kitasato University, Minato-ku, Tokyo 108-8641, Japan
4. Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
5. School of Pharmacy and Pharmaceutical Sciences, and Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan