1. Graduate School of Frontier Sciences, Department of Environment Systems, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa City, Chiba 277-8563, Japan
2. Environmental Science Center, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
3. Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan