Eggs regulate sperm flagellar motility initiation, chemotaxis and inhibition in the coral Acropora digitifera, A-gemmifera and A-tenuis
Eggs regulate sperm flagellar motility initiation, chemotaxis and inhibition in the coral Acropora digitifera, A-gemmifera and A-tenuis
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DOI：
10.1242/jeb.02500
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发表时间：
2006-11-15
影响因子：
2.8
通讯作者：
Okuno, Makoto
中科院分区：
文献类型：
--
作者：
Morita, Masaya;Nishikawa, Akira;Okuno, Makoto
珊瑚在满月前后同时大量产卵。大多数Acropora物种将配子束释放到海水中，配子束是卵子和精子的复合体。然后，配子束被分离成卵子和精子。当精子和卵子相互接触时，卵子就受精了。然而，在有许多不同物种的卵子存在的情况下，精子是如何与同一物种的卵子相遇的，以及卵子是如何防止不同物种的精子受精的，这些都还不清楚。在本研究中，我们观察到A. digitalfera、A. gemmifera和A. tenuis精子在靠近卵子的地方表现出运动起始/吸引。精子在海水中是完全不动的，但当它们靠近卵子时，它们开始以圆周运动游泳，然后沿着直线接近卵子。精子鞭毛运动不是由不同物种的卵子激活的，这表明卵细胞启动鞭毛运动是物种特有的。此外，在观察条件下，这些物种之间没有发生杂交。此外，当许多精子接近卵子时，活力激活的精子变得静止。本研究首次报道了卵子分泌固定因子。我们的研究结果表明，鞭毛运动调节的进化是为了避免在产卵过程中不同物种之间的杂交。
Corals perform simultaneous mass spawning around the full moon. Most Acropora species release gamete bundles, which are a complex of eggs and sperm, into the seawater. Then, gamete bundles are separated into eggs and sperm. Eggs are fertilized when sperm and eggs come in contact with each other. However, it is still unclear how sperm meet the eggs of the same species in the presence of many eggs of different species and how eggs guard against the fertilization attempts by sperm of different species. In this study, we observed that A. digitifera, A. gemmifera and A. tenuis sperm showed motility initiation/attraction close to eggs. Sperm were completely immotile in seawater, but they began to swim in circular motion when they came in close proximity to eggs, and then approached the eggs in straightforward paths. Sperm flagellar motility was not activated by an egg from different species, suggesting that motility initiation by the egg is species specific. In addition, hybridization among these species did not occur under observed conditions. Furthermore, motility-activated sperm became quiescent when many sperm approached the eggs. This study is the first report to show that the egg secretes immobilization factor(s). Our results suggest that the flagellar motility regulation has evolved to avoid hybridization among different species during the mass spawning.