Laboratory of Animal Reproduction, Faculty of Agriculture, University of Miyazaki, Gakuen-Kibanadai-Nishi, Miyazaki, Japan.
Anim Reprod Sci. 2010 Aug;121(1-2):181-7. doi: 10.1016/j.anireprosci.2010.04.009. Epub 2010 Apr 13.
In order to conserve the copper pheasants, one of the Japanese 'near threatened' species, the knowledge of the sperm characteristics is the inevitable issue. Therefore, temperature-dependent regulation of copper pheasant sperm motility was investigated in comparison with that of domestic fowl spermatozoa. Motility of intact spermatozoa from both species was markedly affected by temperature. During incubation at 30 degrees C, copper pheasant spermatozoa showed around 60-70% motility, but became almost immotile when the temperature was raised to 40 degrees C. Then, when the temperature of the sperm suspension was subsequently cooled to 30 degrees C, the spermatozoa regained their motility. The motility of domestic fowl spermatozoa showed a similar pattern. Temperature also affected the motility of both demembranated copper pheasant and domestic fowl spermatozoa in the same way. The motility of intact copper pheasant and domestic fowl spermatozoa at 30 degrees C was unaffected following the addition of 2 mM CaCl(2), 100 nM calyculin A, an inhibitor of protein phosphatase-type 1 (PP1), or 4 mM diB-cAMP, respectively, compared with those with no effectors. However, the presence of 10 microM ML-7, a selective inhibitor of myosin light chain kinase (MLCK), inhibited motility of spermatozoa from both species. At 40 degrees C, the presence of CaCl(2) or calyculin A restored the motility of spermatozoa from both species, but the addition of diB-cAMP or ML-7 could not prevent the immobilization of spermatozoa. At 30 degrees C in the presence of ATP, the motility of demembranated copper pheasant spermatozoa was over 60% but was inhibited following the addition of 10 microM ML-7; a similar pattern was found with demembranated domestic fowl sperm motility. The motility of demembranated spermatozoa from both species was inhibited following the addition of 2mM EGTA to the reactivation medium at 30 degrees C, but restored by the subsequent addition of 4 mM CaCl(2). These results suggest that copper pheasant sperm motility might be regulated by similar mechanisms to that of domestic fowl spermatozoa: i.e., the balance of Ca(2+)/MLCK or an MLCK-like protein-dependent phosphorylation and PP1-dependent dephosphorylation. The similarity in physiological regulation of spermatozoa from both species shows that extensive technology developed for artificial breeding of the domestic fowl might be applicable to captive breeding of copper pheasants.
为了保护铜雉，这是日本的“近危”物种之一，精子特征的知识是不可避免的问题。因此，我们研究了温度对铜雉精子活力的影响，并与家鸡精子进行了比较。两种物种完整精子的活力都明显受到温度的影响。在 30°C孵育时，铜雉精子的活力约为 60-70%，但当温度升高到 40°C时，精子几乎完全不动。然后，当精子悬液的温度随后冷却到 30°C时，精子恢复了活力。家鸡精子的活力也表现出类似的模式。温度也以相同的方式影响去膜的铜雉和家鸡精子的活力。在 30°C下，加入 2mM CaCl2、100nM calyculin A（一种蛋白磷酸酶 1 型（PP1）抑制剂）或 4mM diB-cAMP 后，完整的铜雉和家鸡精子的活力均不受影响，而无效应物的活力不受影响。然而，10μM ML-7（肌球蛋白轻链激酶（MLCK）的选择性抑制剂）的存在抑制了两种物种的精子活力。在 40°C时，CaCl2 或 calyculin A 的存在恢复了两种物种精子的活力，但加入 diB-cAMP 或 ML-7 不能阻止精子的固定。在 30°C下加入 ATP 时，去膜的铜雉精子的活力超过 60%，但加入 10μM ML-7 后活力受到抑制；去膜的家鸡精子活力也出现类似模式。在 30°C下，在再激活培养基中加入 2mM EGTA 会抑制两种物种去膜精子的活力，但随后加入 4mM CaCl2 会恢复活力。这些结果表明，铜雉精子活力的调节可能与家鸡精子相似：即 Ca2+/MLCK 或 MLCK 样蛋白依赖性磷酸化和 PP1 依赖性去磷酸化之间的平衡。两种物种精子在生理调节上的相似性表明，为家鸡人工繁殖开发的广泛技术可能适用于铜雉的圈养繁殖。
