par Van Gansen, Paulette 
Référence Experimental cell research, 47, 1-2, page (157-166)
Publication Publié, 1967-07
Référence Experimental cell research, 47, 1-2, page (157-166)
Publication Publié, 1967-07
Article révisé par les pairs
| Résumé : | 1. 1. Xenopus eggs were fixed during segmentation; stages 2 and 8, morula and blastula, were chosen. Only the animal hemispheres were ultrasectioned. 2. 2. We observe isolated granules of a mean diameter of 260 Å in all the embryos (Fig. 1). We see also strands of associated granules which look very similar to the isolated ones (Figs. 4, 5 and 6). All those granules are probably a mixture of ribosomes and β-glycogen particles, either isolated or associated. 3. 3. The endoplasmic reticulum of the embryos is built of smooth vesicles as in the unfertilized eggs (Fig. 1). With the exception of a few rough vesicles (Fig. 2) there is no ergastoplasm. Some vesicles contain many granules (Fig. 3). The nature and function of these "plurigranular vesicles" are unknown. 4. 4. The cytoplasm of the blastulae looks rich in electron dense substances is unequally distributed among the granules. The alternation of clear and dark areas of the cytoplasm give a characteristic aspect to the blastomeres (Figs. 7 and 8). 5. 5. In the blastulae, vesicles of 1 to 3 μ diameter are found between the cells. They contain a few membranes and numerous strands of associated granules (Figs. 9 and 10). © 1967. |
