1. Health and Bioscience Laboratories, Meiji Seika Kaisha, Ltd., 5-3-1, Chiyoda, Sakado-shi, Saitama 350-0289, Japan, and Department of Environmental Bioremediation, Graduate School of Agriculture Science, Tohoku University, 1-1 Tsutsumidori Amamiyamachi, Aoba-ku, Sendai, Miyagi 981-8555, Japan