1. Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
2. Center for Research and Development of Bioresources, Organization for Research Promotion, Osaka Prefecture University, 1-2, Gakuen-cho, Naka-ku, Sakai 599-8570, Japan