[The organization of the karyosphere and capsule before oocyte maturation in the common frog].
The oocytes of the 6th stages, according to Dumont (1972), taken from R. temporaria in nature in April were studied. The semithin sections of Araldit-embedded material, as well as preparations of karyospheres with capsules isolated from nuclei using Callan's method (Callan et al., 1987), were analysed. Ultrastructural investigations were carried out both on intact nuclei and on nuclei extracted in 2M NaCl. The April oocytes differ from the winter ones previously analysed by Gruzova and Parfenov (1977), in the distribution of capsule components: the fibrous material surrounds, as previously, the central part of karyosphere, whereas the pseudomembranes penetrate into the chromosome tangle. The fibrous material reveals stability (resistance) to 2M NaCl treatment. Another feature of the April oocytes is the development of small intracellular bodies (0.3-2 microns). These bodies are composed of coiled threads 40-50 nm in diameter and connected with the nucleoli. The morphogenesis of the capsule fibrous component is discussed in connection with the double nature of the capsule material. Participation of actin filaments in the formation of the fibrillar part of the capsule is discussed. A similarity of the bodies composed of coiled threads in oocyte nuclei is drawn with the "coiled bodies" of somatic cell (Lamond, Carmo-Fonseca, 1993).
Pochukalina
G N
GN
Tsarfenov
V N
VN
D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure*; D002875:Chromosomes / Q000648:ultrastructure*; D005260:Female; D008854:Microscopy, Electron / Q000379:methods; D009865:Oocytes / Q000254:growth & development / Q000648:ultrastructure*; D011896:Rana temporaria