Morita Masaya, Okuno Makoto, Susilo Endang Sri, Setyo Bambang Pramono, Martarini Diptarina, Harnadi Lilik, Takemura Akihiro
Department of Chemistry, Biology and Marine Sciences, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan.
Comp Biochem Physiol A Mol Integr Physiol. 2006 Mar;143(3):361-7. doi: 10.1016/j.cbpa.2005.12.020. Epub 2006 Feb 3.
Sperm of most fresh water teleosts become motile when released into the hypotonic fresh water environment, but the role of osmolality and Ca2+ on sperm motility is not clear. Osmotic pressure and Ca2+ concentrations increase from fresh water to brackish water. Java carp Puntius javanicus and catfish Clarias batrachus live and reproduce only in fresh water. On the other hand, goby Oxyeleotris marmorata can acclimate and reproduce from fresh water to brackish water. In the present study, sperm motility and trajectory were compared among these three Indonesian endemic species. Sperm of Java carp, goby, and catfish begun to move in the hypotonic condition (< 200 mOsm/kg). However, the response to Ca2+ was different among these teleosts. In the presence of Ca2+, Java carp sperm swam in circular paths and immediately become quiescent, suggesting that Java carp sperm motility is activated in hypotonic aquatic environment without Ca2+. Goby sperm swam straightforward in the presence or absence of Ca2+. Percentages of motile sperm increased in 100-200 mOsm/kg but suppressed by removal of Ca2+. Regarding sperm motility and trajectory, no response was found in catfish sperm. These results suggest that a response to Ca2+ is different among sperm of the three species and suited to their habitat.
大多数淡水硬骨鱼的精子在释放到低渗的淡水环境中时会变得具有活力，但渗透压和钙离子对精子活力的作用尚不清楚。从淡水到咸淡水，渗透压和钙离子浓度会升高。爪哇鲤（Puntius javanicus）和胡子鲶（Clarias batrachus）仅在淡水中生存和繁殖。另一方面，弹涂鱼（Oxyeleotris marmorata）能够适应从淡水到咸淡水的环境并进行繁殖。在本研究中，对这三种印度尼西亚特有物种的精子活力和轨迹进行了比较。爪哇鲤、弹涂鱼和胡子鲶的精子在低渗条件（<200 mOsm/kg）下开始移动。然而，这些硬骨鱼对钙离子的反应有所不同。在有钙离子存在的情况下，爪哇鲤精子呈圆形游动，然后立即静止，这表明爪哇鲤精子的活力在没有钙离子的低渗水环境中被激活。弹涂鱼精子在有或没有钙离子的情况下都直线游动。活动精子的百分比在100 - 200 mOsm/kg时增加，但去除钙离子后受到抑制。关于精子活力和轨迹，胡子鲶精子没有反应。这些结果表明，这三种物种的精子对钙离子的反应不同，且与其栖息地相适应。
