Schwalm Fritz E, Simpson Ross, Bender Harvey A
Department of Biology and Radiation Laboratory, University of Notre Dame, 46556, Notre Dame, Ind.
Illinois State University, 61761, Normal, Ill., USA.
Wilhelm Roux Arch Entwickl Mech Org. 1971 Sep;166(3):205-218. doi: 10.1007/BF00650030.
Changes in the fine structure of polar granules and distribution of these granules in the egg and pole cells during the earliest stages of embryonic development have been observed in the eggs ofCoelopa frigida. 1. Polar granules are composed of dense granules 25-35 Å in diameter. These dense granules associate in different patterns during the cleavage stages of theCoelopa egg. 2. From early cleavage until shortly before blastema formation (preblastoderm stage) the dense granules form globular subunits, 200-250 Å in diameter, within the polar granules. These subunits become more distinct in later cleavage stages. 3. With the formation of the blastema the globular subunits are transformed into electron dense rods of varying length and approximately the same diameter as the globular subunits. Groups of parallel rods are arranged in different directions within each polar granule. 4. When pole cells have been formed, all the polar granules within each cell associate to form a complex, shaped like a concave disc, on the distal side of the nucleus or on the side pointing toward neighboring pole cells. Those components contributed by individual polar granules can still be identified within the disc. 5. The possibility of a correlation between blastema formation (i.e., the arrival of nuclei in the pole plasm) and the structural change within polar granules as an indication of nucleocytoplasmic interaction is discussed.
在寒芒蝇的卵中观察到了胚胎发育最早阶段极性颗粒精细结构的变化以及这些颗粒在卵和极细胞中的分布情况。1. 极性颗粒由直径为25 - 35埃的致密颗粒组成。在寒芒蝇卵的卵裂阶段，这些致密颗粒以不同模式聚集。2. 从早期卵裂到芽基形成前不久（前胚盘阶段），致密颗粒在极性颗粒内形成直径为200 - 250埃的球状亚基。这些亚基在后期卵裂阶段变得更加明显。3. 随着芽基的形成，球状亚基转变为长度各异、直径与球状亚基大致相同的电子致密棒。每组平行排列的棒在每个极性颗粒内以不同方向排列。4. 当极细胞形成时，每个细胞内的所有极性颗粒聚集形成一个复合体，形状像一个凹盘，位于细胞核的远端或指向相邻极细胞的一侧。在这个盘状物中仍可识别出各个极性颗粒的组成部分。5. 讨论了芽基形成（即细胞核到达极质）与极性颗粒内结构变化之间存在关联的可能性，这种关联可作为核质相互作用的一种指示。
