両生類の卵形成過程の研究 : III.ニホンアカガエルの初期卵黄形成

概要

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Electron microscopic studies have shown that there is a dual mechanism for the formation of proteinaceous yolk in young oocytes of Rana japonica as in those of other species of the same genus. In the first mode of formation crystalline yolk bodies begin to appear within the vesicular structure enclosing varying amounts of granular and fibrillar components in the peripheral cytoplasm of oocytes 200-250 μ in diameter. Small vesicles containing rather dark material appear to be added to the "yolk precursor vesicles" during their growth. Regarding the origin of these small vesicles, it is presumed to be derived from pinocytosis on the surface of oocytes. In the second mode of formation, plate-like hexagonally shaped yolk bodies originate within the cristae of mitochondria. These plate-like crystalline bodies grow into hexagonally shaped cylindrical yolk bodies the diameter of which is larger than that of mitochondria, therefore as they increase in size the yolk-containing part becomes enlarged compared with other part of the mitochondrion. It is emphasized that there is characteristic difference in the mode of yolk formation depending on the species of Rana, though it is characteristic of this genus that there is a dual mechanism for the formation of proteinaceous yolk.
社団法人日本動物学会の論文
1967-04-15