Studies on oocyte growth by the chimera frog of diploid and triploid

受精后冷处理可产生三倍体青蛙非洲爪蟾。三倍体卵巢中的卵母细胞不能生长，不能成为卵母细胞。本研究通过制备二倍体和三倍体生殖细胞嵌合体，研究生殖细胞和卵巢其他间充质组织与卵母细胞生长的关系.将含原始生殖细胞的区域切割成块，并在早期尾芽期在二倍体和三倍体胚胎之间交换。结果：1.手术后的胚胎外部形态基本正常，并于5个月后对性腺进行组织学观察.以二倍体胚胎间原始生殖细胞交换胚胎作为手术效果的对照实验。它们的性腺正常，与未手术的二倍体青蛙完全相同。这些结果表明，原始生殖细胞的交换操作对卵母细胞的生长没有影响.三倍体青蛙含有二倍体生殖细胞，卵巢中有许多成熟的卵母细胞。说明二倍体卵母细胞可以在三倍体环境中生长.二倍体蛙卵巢含有三倍体生殖细胞，与正常二倍体蛙卵巢不同，而与三倍体蛙卵巢相似。也就是说，三倍体生殖细胞不能在二倍体子房和系统结构中生长。上述结果提示，三倍体卵母细胞的生长停滞是由于生殖细胞的三倍体性所致。

Triploid frog, Xenopus laevis can be produced by the cold treatment after fertilization. The oocyte in triploid ovary can not grow and does not become ooxocyte. Chimera frog between diploid and triploid germ cell was produced to study the relationship of germ cell and other mesenchymal tissue in ovary in relation to oocyte growth.1. Primordial germ cell containing area was cut out as a block and exchanged between diploid and triploid embryos at early tail bud stage. The operated embryos were seems to be normal in external morphology and their gonad were studied histologically at 5 month after metamorphosis.2. Primordial germ cell exchanged embryos between diploid one were produced as the control experiment of operation effect. Their gonads were normal and exactly same as those of not-operated diploid frogs. These results showed that exchange operation of primordial germ cell did not affect on the growth of oocyte.3. The triploid frogs contained diploid germ cells showed many grown oocytes in their ovaries. These results indicated that diploid oocytes can grow in triploid environment.4. The ovaries of diploid frogs contained triploid germ cells were different from those of normal diploid ones and similar to triploid frog ovaries. In other words, the triploid germ cells did not grow in diploid ovary and systemic structures. These results mentioned above suggest that the growth arrest of triploid oocytes are due to the triploidy of germ cells.