1. Department of Parasitology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan,
2. Division of Cell Proliferation, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan,
3. Department of Biology, Faculty of Science, Nara Women’s University, Nara, Nara 630-8263, Japan,
4. Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA,
5. Department of Biosciences, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan, and
6. Department of Biology, Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan