1. Department of Bioresource Engineering, Yamagata University, Tsuruoka-shi, Yamagata 997, Japan (T.T., W.M.)
2. Frontier Research Program, The Institute of Physical and Chemical Research, Wako-shi, Saitama 351-01, Japan (H.K., Y.K.)
3. Department of Applied Biological Science, Science University of Tokyo, Noda-shi, Chiba 278, Japan (Y.I.)