1. Department of Nutritional Science, Kobe Gakuin University, Kobe, Hyogo, 651-2180 Japan.
2. Cooperative Research Center of Life Sciences, Kobe Gakuin University, Kobe, Hyogo, 650-8586 Japan.
3. Corresponding author. Phone: +78-974-1551. Fax: +78-974-5689. E-mail: yoshida@nutr.kobegakuin.ac.jp
4. Department of Biochemical Sciences, College of Sciences, Ritsumeikan University Kusatu, Shiga, 525-8577 Japan.