Study on Gametogenesis and Sex Steroids of Scleractinian Coral Goniopora burgosi in Bitou Cape, Taiwan

• Main Authors: Li, Han-Ru, 李函如
• Other Authors: shikina, shinya
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/4pntfm

碩士 === 國立臺灣海洋大學 === 海洋環境與生態研究所 === 106 === Sexual reproduction is among the most important biological phenomenon required for establishing coral populations. To date, most studies regarding coral sexual reproduction have focused on the environmental factors affecting coral gametogenesis and spawning. However, little studies have been performed on the intrinsic mechanisms underlying coral sexual reproduction. Sex steroids in vertebrates play fundamental roles in gametogenesis and spawning. Previous studies found that stony coral tissues contain sex steroids (e.g., 17beta-estradiol, testosterone). Interestingly, the concentration of 17beta-estradiol in the coral tissue elevated when the coral approached to the spawning month in the stony coral Euphyllia ancora. These findings suggest that sex steroids may be involved in the regulation of gametogenesis, oocyte maturation, and/or spawning in corals. However, the elevation in the concentration of 17beta-estradiol has only reported in E. ancora, it is still unclear that similar patterns can be observed in other corals. To get a better understanding of the function of steroids in the sexual reproduction, especially in germ cell development, of the stony corals, the present study investigated the relationship between gametogenesis and sex steroids using a stony coral Goniopora burgosi. G. burgosi colonies were collected at Pitouchiao near northern Taiwan at different timings over the periods during October 2016-December 2017. The germ cell development was investigated by immunohistochemical analysis with anti-Piwi (germ-cell marker) antibody. The sex steroids (17beta-estradiol, progesterone, and testosterone) in the tissue extract of G. burgosi were determined by UPLC-MS. We found that the germ development took approximately one year in both sexes. It started from August and proceeds until the next spawning periods, July or August. UPLC-MS analysis confirmed the presence of progesterone and testosterone in the most coral tissue that we examined. However, the concentration of these steroids in the coral tissues were basically very low throughout the year, and the distinct elevation in the levels of these steroids were not observed even in the corals that approached to the spawning month. Further studies were required to clarify the function of steroids in in germ cell development of the stony corals.