1. Department of Anatomy, College of Veterinary Medicine, Chonnam National University, 300 Yongbong-Dong, Puk-Ku, Kwangju, 500-757, South Korea
2. Food Irradiation Team, Korea Atomic Energy Research Institute, Taejeon, South Korea
3. Department of Biology, College of Natural Science, Sunchon National University, Sunchon, South Korea