. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. D Figure 6. Transmission electron microscopy of microvilli and fixing processes. lA. B) Quick-free/e and freeze-substitution fixation. (C-F) Chemical fixation. (A) An immature oocyte. Microvilli were identified embedded in the vitelline coat (VC) on the surface of the oocyte. Note bundles of fibers within microvilli. (B) A maturing oocyte 40 min after 1-MeAde treatment. Fiber bundles inside microvilli extend into the cytoplasm (white arrow). On the fiber bundles, some repeated strips are observed (black arrowheads). (C) Thir
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. D Figure 6. Transmission electron microscopy of microvilli and fixing processes. lA. B) Quick-free/e and freeze-substitution fixation. (C-F) Chemical fixation. (A) An immature oocyte. Microvilli were identified embedded in the vitelline coat (VC) on the surface of the oocyte. Note bundles of fibers within microvilli. (B) A maturing oocyte 40 min after 1-MeAde treatment. Fiber bundles inside microvilli extend into the cytoplasm (white arrow). On the fiber bundles, some repeated strips are observed (black arrowheads). (C) Thirty seconds after insemination (40 min after 1-MeAde treatment). The tips of microvilli (arrows) were connected to the vitelline coat that was transforming into the fertilization envelope. (D) One minute after insemination. Microvilli were lengthening with the elevation of the fertilization envelope, thereby transforming themselves into the fixing processes. A fixing process attached to the electron-dense innermost layer of the fertilization envelope (arrow). (E) Two minutes after insemination. The length of microvilli increased compared to that in D. A fixing process attached to the electron-dense innermost layer of the fertilization envelope (arrow). (F) The 8-cell stage. Short fixing processes were observed on the blastomere surface adherent to the fertilization envelope. The tips ol the processes were connected with the fertilization envelope (arrows). Scale bars: 500 nm (A-E). and 2 /^m (F). onto the cell surface and discharged the contents into the perivitelline space (Fig. 8B-D: cf. Fig. 6D, E), resulting in their disappearance from the cytoplasm (Fig. 6F). These granules are therefore considered to be cortical granules. Following exocytosis of the cortical granules, electron- dense particles appeared in the perivitelline space, indicat- ing that the particles correspond to the perivitelline-space particles observed under light microscopy (Fig. 4A, B) and are derived from
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
