紫外线诱导太平洋牡蛎雄核发育的研究

Studies on the Induction of Androgenesis in the Pacific Oyster, Crassostrea gigas by Ultraviolet Irradiation

为诱导太平洋牡蛎雄核发育单倍体 ,本文研究利用紫外线诱导太平洋牡蛎雄核发育的条件。结果表明 :在强度为2 .8mW·cm-2 ·s-1的紫外线 (2 5 4nm)下分别照射 0 ,10 ,15 ,2 0 ,2 5 ,3 0 ,3 5 ,40 ,5 0 ,60 ,70和 80s后 ,照射 3 0s的卵子能够保持较高的受精率 (73 .5 % ) ;该处理组的D形幼虫发生率为 0。染色体检查结果显示此时单倍体率最高 (4 7.8% )。证明在强度为2 .8mW·cm-2 ·s-1的紫外线下照射 3 0s是获得雄核发育单倍体的适宜条件。研究还表明受精率和D形幼虫发生率随照射时间的增加而下降 ,遗传失活的卵子与正常精子受精后其胚胎发育至D形幼虫前期停止。实验中各处理组均出现非整倍体。原因可能由于紫外线对卵子染色体遗传失活的作用程度不同以及光线对DNA的修复作用。

Effects of ultraviolet (UV) irradiation on genetic inactivation of eggs were examined in the Pacific oyster, Crassostrea gigas. In this experiment egg suspension was treated with the UV light (254 nm, intensity 2.8 mW·cm -2·s -1) for 0,10,15,20,25,30,35,40,50,60,70 or 80s. The results showed that when the eggs were irradiated for 30s and mixed with normal sperm, the fertilization rate was relatively high (73.5%) and the developmental rate became zero. The results of chromosome observation showed that under this condition the rate of haploid was the highest (47.8%). This result indicated that irradiation for 30 s at UV intensity 2.8mW·cm -2·s -1 was the optimum dose to achieve haploid androgenesis. The rates of the fertilization and the development of D-shaped larvae decreased with increasing irradiation time, and the development of the genetically inactivated eggs fertilized with the normal sperm terminated before reaching the D-shaped stage. Aneuploids were found in this study. Occurrence of these aneuploids is probably attributed to different degrees of maternal chromosomal inactivation by UV irradiation and/or DNA repair.