鹰爪虾卵子激活及卵裂的研究

OOCYTE ACTIVATION AND CLEAVAGE IN TRACHYPENAEUS CURVIROSTRIS

使用激光扫描共聚焦显微镜及电子显微镜对鹰爪虾的卵子产入海水中激活过程及卵裂特征进行研究。结果表明 ,鹰爪虾成熟卵子一接触海水立即被激活而发生皮层反应 :先排出皮质贮泡内的胶质前体 ,形成胶质层 ,进而释放皮层颗粒 ,形成孵化膜。孵化膜举起时 ,有许多囊泡排入卵周隙。在发生皮层反应的过程中 ,减数分裂完成 ,相继排出第一极体和第二极体。卵子可由海水激活而无需受精。未受精卵可以由海水刺激发生皮层反应并完成减数分裂 ,这一过程与受精卵的激活相同。未受精卵不能正常分裂 ,极少数可分裂为大小不等的子细胞。在 2 0℃水温条件下 ,受精卵在卵子产出后 70分钟开始第一次卵裂。此后胚胎 30分钟左右分裂一次 ,在 4细胞期 ,分裂球即开始发生扭转 ,8细胞期分裂球进一步扭转 ,表现出原始的螺旋卵裂的特征 ,16细胞期开始 ,分裂具有两侧对称的特性 。

The activation process of matured oocyte and its spiral cleavage in Trachypenaeus curvirostris were studied in 1996 to 1997 using laser scanning confocal microscope and electron microscope.The results revealed that the oocyte was quickly activated by seawater,and it turned round and began cortical reaction.Cortical vesicles (CVs) were released and dispersed to form jelly layer(JL).Cortical granules (CGs) were released and dispersed to form hatching envelope(HE).Matured meiosis was completed during cortical reaction,and polar body (Pbl) and polar body 2(Pb2) were released.The oocyte activation was exited by seawater and not by fertilization Fertilized eggs and unfertilized eggs had the same activation process.But the unfertilized eggs could not cleave or could only divide into a few cells with different sizes. \ \ At 20℃,the ferilized egg began cleavage at 70 min after the oocyte was spawned into sea water,and divided once at 30 min intervals.Spiral cleavage began at the end of 4cellstage, and the spiral character was obvious at 8cellstage.Rightleft symmetry began at 16cellstage when the spiral character disappeared.