1. Department of Bacteriology, Nagoya University School of Medicine, Showa-ku, Nagoya, Aichi 466-8550,1
2. Department of Bacteriology, Aichi Prefectural Institute of Public Health, Kita-ku, Nagoya, Aichi 462-8576,2 and
3. Department of Pharmacology, Aichi Medical University School of Medicine, Nagakute, Aichi 480-1195,3 Japan