1. Department of Food Science and Technology and Department of Agricultural Biology, Seoul National University, Suwon 441-744, Korea; Department of Biology, University of Inchon, Inchon 402-749, Korea; Department of Life Science, Pohang University of Science and Technology, Pohang, Kyungbook 790-784, Korea; Samyang Genex Research Institute, Taejeon 305-348, Korea; and A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia