Japanese society of Ova Research

Abstract

Vol.21 No.3

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Acquirement of Oocyte-activating Factor in Antarctic Minke Whale (Balaenoptera bonaerensis) Spermatogenic Cells, Assessed by Meiosis Resumption of Microinseminated Mouse Oocytes
JMOR, 21(3) 149-156, 2004
DOI: 10.1274/jmor.21.149
Kazue Amemiya1 Yoshihito Iwanami1 Toshihiro Kobayashi2 Tatsuma Terao1 Yutaka Fukui3 Hajime Ishikawa4 Seiji Ohsumi4 Masumi Hirabayashi5,6 Shinichi Hochi1,2* 
1Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
2Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
3Obihiro University of Agriculture and Veterinary Medicine, W2-S11 Inada-cho, Obihiro, Hokkaido 080-8555, Japan
4The Institute of Cetacean Research, 4-18 Toyomi-cho, Chuo-ku, Tokyo 104-0055, Japan
5National Institute for Physiological Sciences, 5-1 Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
6School of Life Science, The Graduate University of Advanced Studies, 5-1 Myodaiji-cho, Okazaki, Aichi 444-8787, Japan

The presence or absence of sperm-borne oocyte-activating factor (SOAF) in the Antarctic minke whale haploid spermatogenic cells was determined by assessing the meiosis resumption of microinseminated mouse oocytes. The relative capacity of mature spermatozoa from mouse, cattle and whale to resume the meiosis of BDF1 mouse oocytes was, respectively, 90.5, 84.6 and 76.5%, while nuclear changes in non-treated or buffer-injected oocytes did not occur after 90-min culture. In the whales, the late-stage elongating spermatids as well as the testicular spermatozoa triggered the meiosis resumption of mouse oocytes at similar rates (oocyte activation rates; 68.0 and 62.5%, respectively). The oocyte activating capacity of the early-stage elongating spermatids was significantly lower (25.0%), and the round spermatids did not activate mouse oocytes at all. This result suggests that the SOAF activity in the Antarctic minke whales is acquired during the early phase of spermiogenesis.

Keywords: Egg activation  Minke whale  Mouse test  Sperm factor  Spermiogenesis 
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