Biological Properities and Reproductive Ability of Chimeric Fish Produced by Blastderm Reconstruction.

(1)从细胞学、组织学和生物化学的角度对金鱼原肠胚前阶段进行了研究，以期为发育技术提供依据。在20C条件下，受精后50min至6h，每30min约发生9次同步卵裂，随后转置非同步卵裂期，提示中囊胚过渡（MBT）。这个时间阶段是囊胚中期。在受精后8h，用原位杂交法检测中胚层标记物（鹅样和无尾）的基因组表达。这个时间被称为囊胚晚期。(2)对金鱼和斑马鱼的原始生殖细胞（PGCs）分化进行组织学观察。在金鱼的7 ~ 9点和斑马鱼的6点时在组织学上检测到PGCs，但在这之前没有检测到PGCs。(3)为了阐明金鱼原始生殖细胞（PGCs）的起源，研究了囊胚中期胚皮的部分缺失或重复是否会影响受精后10 d幼虫原始生殖细胞的数量。胚下半部分切除后的幼体PGCs数量减少，胚上半部分切除后的幼体PGCs数量减少。在囊胚下半部分复制的胚胎发育成的幼虫中，这些因子增加。(4)在中囊胚期将鲫鱼囊胚下部移植到金鱼囊胚中部的嵌合鱼可繁殖出两个品系的卵。在斑马鱼囊胚中期，将金黄色菌株的整个囊胚移植到野生菌株囊胚的动物部分，嵌合鱼也能繁殖出两种菌株的卵。

(1) In order to contribute developmental technology, the pre-gastrula stage were studied by cytological, histological or biochemical viewpoints in goldfish. Synchronous cleavages occur 9 times every about 30min from 50min to 6h post-fertilization at 20C,and, thereafter, transpose asynchronous phase, suggesting mid-blastula transition (MBT). This timing is staged as the mid-blastula. Genomic expression of mesodermal markers, goosecoid and no tail, are detected with in situ hybridization assay from 8h post-fertilization. This timing is staged as the late-blastula.(2) Histological observation was performed for diffentiation of primordial germ cells (PGCs) in goldfish and zebrafish. PGCs were histologically detected at the 7 to 9 somite stage in goldfish and at the 6 somite stage in zebrafish, but did not before the stages.(3) In order to elucidate the origin or primordial germ cells (PGCs) of goldfish, it was investigated whether partial deletion or duplication of blastoderm at the mid-blastula stage effects on the numbers of PGCs in 10-day-larva after fertilization or not. The number of PGCs were decreased in larvac developed from the embryos extirpated lower half of blastoderm, but not in larvae from the embryos extirpated upper half of blastderm. Those were increased in larvae developed from the embryos duplicated lower half of blastoderm.(4) The chimeric fish which lower part of crucian-carp blastoderm was transplanted to the middle part of goldfish blastoderm at the midblastula stage, reproduced the eggs from two strains. The chimeric fish in zebrafish, in which entire blastoderm of golden strain was transplanted to animal part of blastoderm of wild strain at the mid-blastula stage, also reproduced the eggs of two strains.