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G E Onishchenko

Publications and source records attributed to G E Onishchenko.

At least 37 records · Page 2Linked to original sources
PubMed1987

[Proliferation characteristics of multinucleate cells during prolonged exposure to cytochalasin B].

The growth of the Chinese hamster cell cultures for 7 days after the stopping of the prolonged cell cultivation with cytochalasin B (5 micrograms/ml, 7 days), on the one hand, results in the decrease in the amount of multinucleate cells from 75 to 25%. On the other hand, it leads to the appearance of a new class of multinucleate cells with more than 7 nuclei. By the 2nd day a rapid increase in the proliferation rate is observed both in uninucleate and multinucleate cells. Then, by the 7th day, the rate of proliferation activity of multinucleate cells decrease more quickly than that of uninucleate ones. It is shown that during a prolonged cell cultivation after the action of cytochalasin B all classes of multinucleate cells are able to DNA reproduction. A question on proliferation abilities of multinucleate cells is discussed.

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PubMed1987

[Role of multipolar mitoses in the proliferation of multinucleate cells induced by cytochalasin B].

A prolonged action of cytochalasin B results in the formation of numerous multipolar mitoses (26%) in Chinese hamster cell cultures. The transition to multipolar mitoses in the presence of cytochalasin B is not accompanied by K-mitotic delay. It is shown that a multipolar mitosis without cytoplasmic division is one of the main causes of multinucleation development in cytochalasin B-treated cultures. After stopping the drug action the cytochalasin B-induced multinucleate cells continue to divide by multipolar mitosis. In this case it completes with cytokinesis and, probably, leads to a decrease in the number of nuclei per cell. The origin of multipolar mitotic apparatus after the action of cytochalasin B is discussed in addition to the role of multipolar mitosis in formation and proliferation of multinucleate cells.

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PubMed1986

[Structure of the centriolar complex in the hepatocytes of intact and regenerating mouse live].

The structure of the cellular center in polyploid hepatocytes of intact and regenerating liver of adult mice has been studied. It was shown that the structure of the centriolar complex depends on stages of the cellular cycle. No pericentriolar structures (such as satellites, appendages and others) and cytoplasmic microtubules were found in the centriolar complex within G0-period. The satellites and appendages are formed in the half of the centrioles within G1-period. The microtubules can branch off some satellites; the daughter centrioles begin to form within S-period; there are diplosomes in the cells within G2-period, some mother centrioles are surrounded with the fine fibrillar halo. It is concluded that the structure of the centriolar complex within G0-period is distinguished by that within G1-period. The structure of the centriolar complex in polyploid hepatocytes has the same feature of reorganization in certain interphase periods of the cell cycle as in diploid cells of some cultured cells and the thyroid epithelium.

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PubMed1986

[Structure of the centriole complex in mouse hepatocytes in the experimental induction of a G2 block].

In the regenerating liver hepatocytes the centriolar cycle is retarded corresponding to the delay of the nuclear cycle up to the beginning of G2-block. A prolonged staying of cells in the premitotic condition results in the phenomenon that according to their DNA these cells correspond to the G2-period, whereas according to their centriolar complex structure they move into the following G1 and G0-periods, passing mitosis. Thus, in the G2-blocked hepatocytes there is a separation of the nuclear cycle and centriolar cycles. Moreover, during the diping action the centriolar capacity of forming cytoplasmic and mitotic microtubules is suppressed.

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PubMed1984

[Ultrastructure of the mitotic apparatus of metaphase cells in a pig embryo kidney tissue culture after stopping the action of 2-mercaptoethanol].

The ultrastructure of the metaphase mitotic apparatus has been studied in the KEPV cells during 6 hours after the removal of 2-mercaptoethanol (0.001 M). Starting from the analysis of chromosome disposition, the structures of the kinetochore regions and of the mitotic spindle poles, and the degree of integrity of the mitotic spindle microtubules, six types of metaphase cells were revealed. A comparison of the results of the present paper with those of the earlier studies enabled us to present the dynamics of the metaphase mitotic apparatus reconstruction. Four basic stages are revealed in this process. At the first stage, the K-metaphase centrioles form diplosomes again, the number and extent of kinetochore microtubules increase too. At the second stage, the metaphase plate forms, but interpolar and astral microtubules are absent. At the third stage, the structure of the kinetochore regions becomes normal. Thus, the metaphase plate may have formed before the orientation of kinetochores to the poles took place. At the fourth stage, the interpolar and astral microtubules appear; the mitotic spindle reestablishes completely. It is supposed that the formation and functioning of the mitotic apparatus is not confined to the interaction of microtubules of different types.

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PubMed1984

[Structural changes in the mitotic apparatus of metaphase cells exposed to 2-mercaptoethanol in a porcine embryonic kidney cell culture. A light microscopy study].

The sequence of reconstruction of the metaphase mitotic apparatus of the KEPV cells under the action of 2-mercaptoethanol (0.001 M) and after moving off the agent has been studied. In the presence of 2-mercaptoethanol, a destruction of the metaphase plate and that of the mitotic spindle proceed independently. The destruction of the mitotic spindle does not involve an immediate disorganization of the metaphase plate, and vice versa. In the course of resumption of the normal division after moving off the agent, the restoration of the mitotic apparatus structure proceeds within a definite temporal sequence: at first, the mitotic spindle reestablishes, and after that the metaphase plate forms. Distinctions between the 2-mercaptoethanol action and the action of other antimitotic agents are discussed.

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PubMed1983

[Effect of 2-mercaptoethanol on the individual periods of the mitotic cycle].

Dynamics of the mitotic cycle of the KEPV cells being on different interphase stages at the start of a 20 hour 2-mercaptoethanol (0.001 M) treatment has been studied during the treatment and for 11 hours after washing out the agent. The KEPV cells affected by mercaptoethanol during the interphase (G1, S, G2) were shown to continue their passage through the cycle to enter mitosis, but part of the cells of the S period and of the first half of the G2 period were arrested in the interphase. In the presence of mercaptoethanol, mitotic cells reach the metaphase stage, and their further behaviour depends on the duration of the treatment. For the first 8 hours of treatment, a phase of "unstable block" exists for cells that were in S and G2 periods at the beginning of treatment, while other cells are transformed into K-metaphases. 8 hours later a phase of "stable block" occurs and all the normal metaphases are transformed into K-metaphases. After washing out the culture from mercaptoethanol the cells are ejected from the block in K-metaphase. The transformation from K-metaphase into the normal metaphase is realised in the course of this process. The cells which were in S and G2 periods at the beginning of the treatment are ejected from the block simultaneously after washing, while the cells of the G1 period--with a small delay. After washing out mercaptoethanol the cells that were in the interphase (G1, S, G2) at the beginning of the treatment are capable of producing both multipolar mitoses and mitoses without cytotomy.

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PubMed1983

[Centriolar complex in somatic cell hybrids (mouse X Chinese hamster)].

The ultrastructure of centriolar complex in interphase cells and in for a long time dividing somatic hybrid cells (mouse X Chinese hamster) has been investigated. It was found that in the majority of hybrid cells (about 80%) the centriolar complex consists of a higher quantity of centrioles than in the parent cells; the fine structure of the centriolar complex has features characteristic of the centrioles of both the parents; the numerous centrioles have a capacity of organizing individual poles of the spindle of division to constitute the ground for multipolar mitosis in the hybrid cells. Besides that, hybrid cells were found with the centriole number corresponding to that in diploid cells. According to our preliminary data, the ultrastructure of these hybrid centrioles is like that in murine cells.

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PubMed1981

[Dynamics of the mitotic cycle and mitosis anomalies in 2-mercaptoethanol action on pig embryo kidney tissue culture cells].

The effect of 2-mercaptoethanol on the dynamics of mitotic cycle was examined in cells of a porcine embryo kidney culture. 2-mercaptoethanol is shown to block cell division in C-metaphase-like figures. After the agent removal the block was stopped, and cells proceeded to a normal metaphase again. The presence of 2-mercaptoethanol does not prevent the S/G2 transition, the entry of cells to the prophase and then to the normal metaphase. At the same time, the length of G2-period of interphase appears to remain normal. In a porcine embryo kidney culture 2-mercaptoethanol induced multipolar mitoses and mitoses without cytokinesis. The number of multipolar mitoses increased with the increase in the time of incubation.

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PubMed1981

[Ultrastructure of the mitotic apparatus in metaphase cells exposed to 2-mercaptoethanol in embryonic swine kidney tissue culture].

The ultrastructure of the mitotic apparatus in metaphasic cells of the porcine embryo kidney culture was studied in the course of the 20 hour treatment with 2-mercaptoethanol (0.001M). In these conditions metaphasic cells were recognized according to the following signs: chromosome disposition; the degree of spindle microtubule destruction; the structure of spindle poles, and the organization of kinetochore regions. On this basis, five types of metaphasic cells have been distinguished. It is suggested that modifications of the mitotic apparatus in these metaphasic types may reflect the reorganization of all its parts (metaphasic plate, mitotic spindle, spindle poles) that occur in the process of the transformation of mitotic cells, from the normal metaphase stage to the stage of C-metaphase under the influence of 2-mercaptoethanol treatment.

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PubMed1980

[Structural characteristics of the centromeric heterochromatin of mice].

The ultrastructure of centromeric heterochromatin in the interphase nuclei and mitotic chromosomes has been studied. The centromeric heterochromatin always consists of 10 nm DPN fibrils tightly arranged in a block having no chromonemal level of organization. Chromosome arms contain 20 nm DPN fibrils able to produce chromonemal structures in the prophase and telophase chromosomes of the normal mitosis, and in the metaphase chromosomes after experimental recondensation. The condensed chromatin of chromosome arms in the mitosis and interphase nuclei is less resistant to the dispersing action of hypotonic solutions compared to the centromeric heterochromatin.

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PubMed1978

[Use of the method of double labeling with H3 and C14-thymidine for identification of cells in different periods of interphase].

For the identification of the position of individual cells in G1, S- and G2-periods of mitotic cycle in any heteroploid cell culture, it is suggested to use the Wimber and Quastler radioautographical method of double labeling of cells. It was shown that independent of the basal polidy of the cells by the successive impulse labeling of the cells with H3- and C14-thymidine with the time interval as long as G2 + M, the cells of the G1-period are unlabeled, S-cells are double labeled with C14- and C14 + H3, and G2-cells have only H3-label.

Animals↗
PubMed1978

[Correlation between the number of centrioles and ploidy of mouse liver hepatocytes].

Using the electron microscope it was shown that in interphase hepatocytes with ploidies equal to 2n, 2n.2, 4n, 4n.2 and 8n, the number of centrioles per cell exactly corresponded to the ploidy of the cell. Both in mononuclear and binuclear cells all the centrioles are accumulated in one complex in which each pair of centrioles forms a diplosome. In binuclear cells, the complex of diplosomes is situated at equal distances from each nucleus, thus making the cell centre. The involvement of the supernumerous centrioles in polyploid metaphase cells was detected for the regenerating liver of old mice. It was found that each mitotic pole had at least four centrioles. In the pole, a pair of centrioles forms diplosomes tightly connected to each other. It is suggested that the initially tetraploid cell might divide in this manner. In addition, a question is discussed on how the existence of centrioles can be associated with the mechanism of polyploidization.

Animals↗
PubMed1978

[Centrioles in mouse bone marrow megakaryocytes].

In immature megakaryocytes, centriolar complexes have been observed with 8, 16, or 32 centrioles. In maturing and trombopoetic megakaryocytes, such a centriolar complex is absent, and individual centrioles lie separately in the cytoplasm. It is suggested that the quantitiy of centrioles in the centriolar complex correlates with the cell ploidy, and that only the cells with potential ability to divide have the centriolar complex.

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PubMed1976

[Ultrastructure of the centrometric regions of mouse chromosomes in metaphase chromosomes and interphase nuclei].

The chromatin ultrastructure was studied in the centromeric region of mitotic chromosomes and in interphase nuclei of mouse cells after differential staining on C-band. A new method is suggested to study centromeric region of chromosomes treated by the Giemsa banding technique. Fibers of chromosomes appeared to be packed denser in the centromeric regions of mitotic chromosomes than in arms. The disposition of chromatin fibers in the centromeric chromocentres of interphase nuclei is the same as in the centromeric regions of mitotic chromosomes.

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