1. Department of Medical Technology; Nagoya University Graduate School of Health Science; Nagoya Aichi 461-8673 Japan
2. Nagoya City Public Health Research Institute; Nagoya Aichi 467-8615 Japan
3. Department of Bacteriology; Nagoya University Graduate School of Medicine; Nagoya Aichi 466-8550 Japan
4. Department of Biosciences; Nagoya Institute of Technology Graduate School of Technology; Nagoya Aichi 466-8555 Japan