1. Intestinal Flora Laboratory, The Calpis Food Industry Co., Ltd, Fuchinobe, Sagamihara, Kanagawa, 229, Japan
2. Chemical Laboratory of Intestinal Microbial Products, Kamegai, Niigata, Niigata, 950-21, Japan
3. Department of Biomedical Science, Faculty of Agriculture, The University of Tokyo, Bunkyo-ku, Tokyo, 113, Japan
4. Laboratory for Intestinal Flora, Frontier Research Program, Riken, Wako, Saitama, 351-01, Japan