1. Department of Microbiology and Immunology; Aichi Medical University; Aichi 480-1100 Japan
2. Japan Collection of Microorganisms; The Institute of Physical and Chemical Research (RIKEN); Wako Saitama 351-0198 Japan
3. Department of Bacteriology; Osaka City University Medical School; Osaka Osaka 545-0051 Japan
4. Department of Chemistry, Graduate School of Science; Osaka University; Toyonaka Osaka 560-0043 Japan