Kotani Minoru, Ogiso Yurie, Ozaki Ritsuko, Ikenishi Kohji, Tsugawa Katsuji
Department of Natural Science, Osaka Women's University, Daisen-cho, Sakai, Osaka 590, Japan.
Department of Biology, Faculty of Science, Osaka City University, Sugimoto-cho, Sumiyoshiku, Osaka 558, Japan.
Dev Growth Differ. 1994 Oct;36(5):457-467. doi: 10.1111/j.1440-169X.1994.00457.x.
In order to determine whether or not tadpoles that once lacked primordial germ cells (PGCs) in the genital ridges and dorsal mesentery as a result of ultraviolet (UV) irradiation subsequently contained germ cells at more advanced stages of larval development, the numbers of presumptive PGCs or PGCs were carefully examined in Xenopus tadpoles at Nieuwkoop and Faber's stage 35/36-52 that developed normally from UV-irradiated eggs. No late-appearing germ cells were observed in almost all the UV-irradiated tadpoles examined at stages 49-52. This same population had completely lacked PGCs at about stage 46. Moreover, presumptive PGCs (pPGCs) or cells with granular cytoplasm that reacted with a monoclonal antibody specific for the germ plasm of cleaving Xenopus eggs stayed in the central part of the endoderm cell mass in the irradiated tadpoles at stage 35/36, when the majority of those cells were located in the dorsal part of the endoderm in unirradiated controls. Furthermore, in the irradiated embryos pPGCs were demonstrated to decrease in number with development and eventually to disappear in tadpoles at about stage 40. The results strongly suggest that UV irradiation under the conditions used here totally eliminated germline cells from the irradiated animals.
为了确定因紫外线（UV）照射而在生殖嵴和背系膜中曾经缺乏原始生殖细胞（PGC）的蝌蚪在随后的幼虫发育更高级阶段是否含有生殖细胞，我们仔细检查了从经紫外线照射的卵正常发育而来的非洲爪蟾蝌蚪在Nieuwkoop和Faber分期35/36至52期的推定PGC或PGC数量。在49 - 52期检查的几乎所有经紫外线照射的蝌蚪中，均未观察到后期出现的生殖细胞。同一批蝌蚪在约46期时完全缺乏PGC。此外，在35/36期，经紫外线照射的蝌蚪中，推定PGC（pPGC）或与用于切割非洲爪蟾卵的生殖质特异性单克隆抗体发生反应的具有颗粒状细胞质的细胞停留在内胚层细胞团的中央部分，而在未照射的对照中，这些细胞大多位于内胚层的背侧部分。此外，在经照射的胚胎中，pPGC数量随着发育而减少，最终在约40期的蝌蚪中消失。结果强烈表明，此处所用条件下的紫外线照射完全消除了受照射动物的生殖系细胞。
