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The intact and isolated cortices of the Rana temporaria oocytes were studied at different stages of maturation by means of electron microscopy. In the isolated cortex of definitive oocyte the microfilaments were concentrated mainly in the microvilli, whereas under the plasma membrane there was only a thin disordered net of microfilaments. At the stage of(More)
Heterologous monoclonal antibodies E2 (against rat cytokeratin 8) and OSC-1 (against cytoskeletal preparations of mouse oocytes) were used to study the presence and distribution of cytokeratins in Xenopus oocytes during their maturation and growth. To improve visualization of cytokeratins, more adequate methods of oocyte fixation and processing were(More)
We studied the distribution of two actin-binding proteins, alpha-actinin and vinculin, in the oocytes and eggs of Xenopus laevis. These proteins are localized in the cortical area. A morphological connection of vinculin with the mirofilaments and plasma membrane was shown; the actin matrix in the egg was gold-labeled more intensely than in the oocyte. A(More)
Ultrastructure of oocyte and egg cortical layer isolated in media containing various ions has been studied. The following results were obtained: 1) in cortical layer a two-component cytoskeletal system is present; morphology of this system changes during development; 2) cytoskeleton of the egg cortex acts as a two-component system in response to the(More)
Using immunoblotting and immunofluorescent microscopy, we showed the presence in Xenopus laevis oocytes of two prosomal proteins (27 and 31-33 kDa) and studied their distribution during oogenesis. In the ooplasm, both proteins are detected in prosomal clusters of various size. During previtellogenesis, prosomal proteins are diffusely distributed in the(More)
It is proposed to consider certain states of the cortical actin cytoskeleton corresponding to various stages of oocyte maturation as morphological criteria of the cortical contractility during progesterone-induced oocyte maturation. In the definitive oocyte, the cortical microfilaments form an anisotropic network, while in the mature egg, they form an(More)
The cortex of Xenopus laevis eggs includes as two components the plasma membrane with underlying microfilaments (external layer) and cytoplasmic matrix with embedded pigment granules (internal layer). The both components of the egg cortex are capable of contraction under the influence of calcium ions. The cortex of the fully grown oocyte is not capable of(More)
Microfilaments were shown to be involved in maintaining spatial organization of the Xenopus laevis oocyte by using injections of DNAse I, which selectively destroys F-actin. An original method has been proposed for visualization of polymerized actin at the electron microscope level. Standard histological sections (5-6 um) were deparaffinized, treated with(More)
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