1. Laboratory of Molecular Microbiology, Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical SciencesNagoya UniversityChikusa‐ku, Nagoya464‐8601 Japan
2. Department of Biological Science, Faculty of Science and EngineeringChuo University1‐13‐27 Kasuga, Bunkyo‐kuTokyo112‐8551 Japan