Search results for "Telophase"
showing 5 items of 5 documents
Periodic expression of cell-cycle regulators: A laboratory experiment proposal for students in molecular and cell biology
2018
This article describes a laboratory exercise designed for undergraduate students in the subject of "Regulation of cell proliferation" which allows the students to carry out a research experiment in an important field such as cell cycle control, and to be introduced to a widely used technique in molecular biology laboratories such as the western blot. The cell cycle is regulated by the succession of cyclin-CDK kinase activities. Activation and inactivation of different cyclin-CDK complexes depend on the control of their positive and negative regulators, cyclins and CDK inhibitors (CKIs), respectively. In this experiment, fluctuations in the level of mitotic cyclin Clb2 and CDK inhibitor Sic1…
Spermatocytes of the caddisfly Potamophylax rotundipennis (Trichoptera, Insecta): a fine structure study with emphasis on synaptonemal complex plates…
1996
Abstract Electron microscopy of ultrathin sections was used to study the restructuring of primary spermatocytes in a caddisfly, Potamophylax rotundipennis (Limnephilidae). Spindle structure was also examined using light microscopy of dividing spermatocytes lysed in a microtubule-stabilizing buffer. The bulk of pachytene spermatocytes was usual in that the nuclei contained tripartite synaptonemal complexes (SCs). The SCs were attached end-on to the inner face of the nuclear envelope and loosely surrounded by electron-dense chromatin. Cells of this type gave rise to late prophase I spermatocytes, where SCs were missing and chromatin condensation was advanced. By metaphase I, a conventional bi…
The autoantigen La/SSB: detection on and uptake by mitotic cells.
1992
Abstract The nuclear autoantigen La, a transcription/termination factor of RNA polymerase III, was recently shown to translocalize to the cell surface of growth-stimulated cells during transition from G0- to G1-phase. Here we describe the staining of living mitotic cells with the anti-La mab La11G7. Moreover, La protein added to cell culture medium was able to enter into synchronized mitotic cells. Uptake was inhibited by the anti-La mab. La protein taken up into prophase cells assembled into a fibrillar network. Taken up by ana/telophase cells, La protein was preferentially transported into the newly forming or formed nuclei. This import allowed us to study directly the intranuclear locali…
Strange vesicles with a homogeneous content in spermatocytes and spermatids of a click beetle, Adelocera murina (Elateridae). A fine structure study
1996
Abstract The restructuring of primary spermatocytes of Adelocera murina, a click beetle, is described using electron microscopy of ultrathin sections. Emphasis is on spherical or rod-shaped cytoplasmic inclusions, invested by a unit membrane. The content of the inclusions is slightly more electron-dense than that of the surrounding cytoplasm and homogeneously textured in most cases. The inclusions are missing in spermatogonia but are abundant in prophase I through anaphase I spermatocytes. Their number declines in telophase I. Very similar elements are associated with the distal ends of the outgrowing flagella in metaphase I through telophase I spermatocytes and form the so-called flagellar…
Mutants of Saccharomyces cerevisiae cell division cycle defective in cytokinesis. Biosynthesis of the cell wall and morphology
1982
The four temperature-sensitive mutants of Saccharomyces cerevisiae in the cell division cycle defective in cytokinesis (cdc, 3, 10, 11 and 12), have been analyzed with respect to the biosynthesis of the cell wall polymers. After 3 hours of incubation at the non-permissive temperature (37 degrees C) these strains stop growing. The synthesis of glucan, mannan and chitin (wall polymers) level off in a similar time, but glucan, mannan and chitin synthases remained active for at least 4 hours. If the mutants are analyzed by transmission and scanning electron microscopy different pictures emerge. Two of the mutants cdc 10 and cdc 12, after 3 hours of incubation at 37 degrees C present apparently …