1. 1Division of Microbiology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya, Tokyo 158-8501, Japan
2. 2Mie Prefectural Science and Technology Promotion Center, 3690-1 Sakura-cho, Yokkaichi, Mie 512-1211, Japan
3. 3Department of Oceanography, Tokai University, 3-20-1 Shimizuorido, Shizuoka 424-8610, Japan