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G E Onishchenko

Publications and source records attributed to G E Onishchenko.

At least 19 recordsLinked to original sources
PubMed2004

[Organelle redistribution during PK cell spreading in normal conditions and in the presence of sodium azide].

Cell detachment from solid substratum results in a changed arrangement of cytoplasmic organelles and, primarily, in disruption of the centrosome and Golgi complex colocalization. In the course of cell spreading, reorganization of intracellular compartments occurs by stages. At first, mitochondria disperse in the cytoplasm volume, then the centrosome and Golgi complex unite, and finally collapse of intermediate filaments disappears. In the presence of Na azide the establishment of intracellular compartments during cell spreading proceeds in a similar manner. However, unlike the normal conditions, here atypical intracellular compartments appear: some of these containing lysosomes and lipid inclusions and located in the perinuclear area, and others with extended cisterns of endoplasmic reticulum on the cell periphery. Addiitionally, in the presence of Na azide the density of microtubules and intermediate filaments increases. It has been suggested that changes in the cytoskeleton organization lead to an enhanced cell spreading.

Animals↗
PubMed2003

[Induction of apoptosis in FAF28 cells by the protein synthesis inhibitor cycloheximide].

We have studied the influence of translation of inhibitor cycloheximide (CHI) on the Chinese hamster fibroblast line FAF28. This treatment inhibited the cell cycle and induced apoptosis. A short-term treatment and the following removal of CHI reduced the number of apoptotic cells up to the normal level. Under changed conditions (change in CO2 proportion and pH of cultural medium), the ability of CHI to induce apoptosis increases. The study of cell ultrastructure demonstrates three groups of apoptotic cells differing from each other in the state of cytoplasmic organelles: 1) cells with many well-identified organelles; 2) cells with a scanty number of cytoplasmic organelles; 3) cells lacking any recognizable organelles in the cytoplasm. Presumable causes of this morphological variety of apoptotic cells are discussed.

Animals↗
PubMed2000

[Spreading of porcine kidney epithelial cells under normal condition and under the effect of inhibitors of energy metabolism. I. Dynamics of spreading].

In the present work dynamics of cell spreading on a solid substratum has been investigated in normal conditions and under ATP-synthesis inhibitors. Sodium aside (20 mM), which blocks ATP-synthesis in mitochondria, and N,N-dicyclohexylcarbodiimide (DCCD) (100 mM), which blocks both ATP-synthesis and glycolysis, were ATP-synthesis inhibitors of choice. In the range from the moment of cell plating to 24 h three stages of cell spreading could be distinguished according to the dynamical change of the average projected cell area. At the first stage, within 1.5 h in the control culture the cell area increases rapidly. The slowing of spreading occurs at the second stage, within 1.5-4.0 h. The third stage is characterized by a slow but pronounced increase in cell spreading, which ceases in 24 h. Under inhibitory treatment, the pattern of cell spreading during the first 4 h is essentially the same as in control conditions. The subsequent DCCD action results in cell spreading inhibition; sodium aside, on the contrary, accelerates the spreading. The cell shape analysis has demonstrated that even as early as in 0.5 h the first small polarized cells appear simultaneously with the nonpolarized cells. In control cells, the share of polarized cells increases in almost 2 h, conversely, under drug actions the process of polarization begins earlier to be more pronounced in the presence of sodium aside. Thus, it has been shown that the spreading of PK cells does not require any additional ATP-synthesis. At early stages in normal conditions and under inhibitory treatment the picture of cell spreading is the same. A complete inhibition of ATP-synthesis slow down the process of cell spreading. However, an activation of these processes was observed in cells with low content of ATP, resulting from glycolysis retaining.

Adenosine Triphosphate↗
PubMed2000

[Spreading of porcine kidney epithelial cells under normal conditions and under the effect of inhibitors of energy metabolism. II. Behavior of cellular organelles].

In the present work the behavior of mitochondria and lysosomes during cell spreading has been investigated in normal conditions and under ATP-synthesis inhibitors: sodium aside and N,N-dicyclohexylcarbodiimide (DCCD). In the control culture, microtubules run along the stable edge and perpendicular to the leading edge in most of spreading cells. As a whole, microtubules form a dense network in these cells. However, the radial cells contain bundles of microtubules, radiating from the perinuclear area or form circular arrays around the nucleus. The microtubule network is more dense under inhibitory treatment, than in control conditions. In the control culture the spherical cells display numerous small mitochondria (staining with Rhodamine 123). In the process of cell spreading some elongated mitochondria appear, most of them being localized in the perinuclear area. The mitochondria of cells with radial microtubule organization are directed towards the cell periphery, while in cells with circular bundles of microtubules the mitochondria are localized chaotically. Under DCCD treatment the mitochondria retain the staining for 2-3 h. In the spreading cells, round mitochondria may be distributed all over the cytoplasm. In the presence of sodium aside the mitochondria are not stained. However, by means of phase contrast microscopy some disoriented thread-shaped structures are observed, obviously corresponding to mitochondria. In the control conditions, lysosomes (stained with Acridine orange) in spreading cells are dispersed chaotically, all over the cytoplasm, or are localized in the perinuclear area. In the presence of sodium aside lysosomes are observed only in the perinuclear area. Under DCCD treatment lysosomes do not accumulate the dye. Thus, the cytoskeleton modification and changes in the properties of membrane organelles, induced by ATP-synthesis inhibitors, do not prevent attachment, spreading or cell polarization.

Adenosine Triphosphate↗
PubMed1999

Structural and functional characteristics of the centrosome in gametogenesis and early embryogenesis of animals.

We present a description of the wide spectrum of centrosome behavior during gametogenesis, early development, and cell differentiation. During meiosis and terminal differentiation of gametes there occurs a process of centrosome maturation which includes alterations in characteristics such as the number of centriolar cylinders and their structure if the basal body is formed and ability to function as MTOC, reduplicate, split, and serve as a polar organizer. Such centrosome properties require modifications of the molecular composition. Maturation of the centrosome in gametes may be compared to transformation of centrosome characteristics during terminal differentiation of other cells. After fertilization different properties of maternal and paternal centrosomes are supposed to combine, adding to each other in the fused (hybrid) centrosome of a zygote. Restoration of centrosome features typical in diploid somatic cells takes place in cells of a developing embryo in the course of early cell cycles.

Animals↗
PubMed1999

Microtubule-organizing centers in the mitotic melanophores of Xenopus laevis larvae in vivo: ultrastructural study.

Mitotic melanophores of Xenopus laevis larvae at 51-53 stages of development were morphologically studied using light and electron microscopy, with special reference to their microtubule-organizing centers. These melanophores represented a highly branched cell shape in mitosis, each cell process is distributed with melanosomes without exhibiting any responsiveness to hormonal (melatonin) stimulation, and upon completion of mitosis, recovered the ability to translocate these granules in response to such a stimulus. At the metaphase, these cells contained bipolar or multipolar spindles, whose poles were composed of three zones: the centrosome with centrioles; the centrosphere; and an outlying radial arrangement of microtubules and their associated inclusions. In these mitotic melanophores, a number of microtubules are distributed within the radially stretching cell processes, whereas an abundance of microtubules reside in the spindles. Possible origins of the microtubules observed in these cytoplasmic processes are discussed in relation to the loss of the ability of pigment translocation during mitosis.

Animals↗
PubMed1999

Identification of microtubule-organizing centers in interphase melanophores of Xenopus laevis larvae in vivo.

The morphological characteristics of microtubule-organizing centers (MTOCs) in dermal interphase melanophores of Xenopus laevis larvae in vivo at 51-53 stages of development has been studied using immunostained semi-thick sections by fluorescent microscopy combined with computer image analysis. Computer image analysis of melanophores with aggregated and dispersed pigment granules, stained with the antibodies against the centrosome-specific component (CTR210) and tubulin, has revealed the presence of one main focus of microtubule convergence in the cell body, which coincides with the localization of the centrosome-specific antigen. An electron microscopy of those melanophores has shown that aggregation or dispersion of melanosomes is accompanied by changes in the morphological arrangement of the MTOC/centrosome. The centrosome in melanophores with dispersed pigment exhibits a conventional organization, and their melanosomes are situated in an immediate vicinity of the centrioles. In melanophores with aggregated pigment, MTOC is characterized by a three-zonal organization: the centrosome with centrioles, the centrosphere, and an outlying radial arrangement of microtubules and their associated inclusions. The centrosome in interphase melanophores is presumed to contain a pair of centrioles or numerous centrioles. Because of an inability of detecting additional MTOCs, it has been considered that an active MTOC in interphase melanophores of X. laevis is the centrosome. We assume that remaining intact microtubules in the cytoplasmic processes of mitotic melanophores (Rubina et al., 1999) derive either from the aster or the centrosome active at the interphase.

Animals↗
PubMed1999

Golgi complex is brefeldin A resistant in multidrug resistant cells.

The multidrug resistance (MDR) is one of the main reasons for chemotherapeutic failures in cancer patients. The overexpression of mdr1 gene product, P-glycoprotein (Pgp), leads to the appearance of resistant tumor cells. In the previous paper (Erokhina, 1997) we have demonstrated that the first stages of Pgp-mediated MDR are accompanied by the reorganization of cytoskeleton elements and the vacuolar system. These data were true for two independently isolated sublines of Syrian hamster embryo fibroblasts transformed by Raus sarcoma virus. In this study, we continued the investigation of the properties of the vacuolar system in Pgp-expressing cells. Brefeldin A (BFA), which is not a Pgp substrate, affects different elements of the vacuolar system and blocks vesicular transport. Our data demonstrate that BFA has different effects on parental and resistant cells. In parental cells, the Golgi apparatus and vesicular transport are sensitive to BFA, while in resistant sublines, BFA affects the vesicular transport but not the Golgi apparatus structure. We discuss the existence of similar and different BFA targets in parental and resistant cells and their role in the evolution of multidrug resistance mechanisms.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Effect of colcemid on the centrosome and microtubules in dermal melanophores of Xenopus laevis larvae in vivo.

An electron microscopy study showed that in melanophores with dispersed and aggregated pigment the sensitivity of the centrosome and the stability of microtubules were different and depended on the colcemid concentration. The structure of the centrosome didn't change upon exposure to colcemid in dispersed melanophores. In aggregated melanophores, on exposure to 10(-6) M colcemid, the centrosome retained its structure; colcemid at 10(-5)-10(-3) M caused a dramatic collapse of the centrosome. Treatment of aggregated melanophores with colcemid resulted in the complete disassembly of the microtubules; though microtubules in dispersed melanophores appear to be colcemid resistant. Light microscopy studies indicated that in Xenopus melanophores with aggregated or dispersed pigment melanosomes didn't change their location after exposure to 10(-3)-10(-6) M colcemid. Subsequent incubation in colcemid-free medium revealed that the cells retained their ability to translocate melanosomes in response to hormone stimulation. Electron microscopy data revealed the inactivation of the centrosome as MTOC (microtubule-organizing center) in dispersed melanophores with melatonin substituted for MSH in the presence of colcemid. In contrast, with melanocyte-stimulating hormone (MSH) substituted for melatonin, we observed the activation of the centrosome in aggregated cells. We showed that in aggregated melanophores pigment movement proceeded in the complete absence of microtubules, suggesting the involvement of a microtubule-independent component in the hormone-induced melanosome dispersion. However, we observed abnormal aggregation along colcemid-resistent microtubules in dispersed melanophores, suggesting the involvement of not only stable but also labile microtubules in the centripetal movement of melanosomes. The results raise the intriguing questions about the mechanism of the hormone and colcemid action on the centrosome structure and microtubule network in melanophores with dispersed and aggregated pigment.

Animals↗
PubMed1995

Centriolar cycle of fused cells.

Ultrastructure of centrioles of fused cells containing heterophasic interphase nuclei, premature chromosome condensation, and a telophase-like nucleus were studied. The study indicated that the heterophasic cellular environments contributed by the different cell partners exert a mutually opposite effect on the structure of centrioles. The G1-cell partner suppresses replication of S-centrioles. Asynchronous replications of G1 and S-stage centrioles were observed in some G1-S, G1-G2 and S-G2 fused cells. In interphase-mitotic fused cells, centrioles of interphase stages underwent mitotic activation when their nuclei were induced to premature chromosome condensation. Daughter centrioles of G1-, S-, and G2-stages were also capable of mitotic activation independently if they were separated from their mother centriole. Inactive centrioles were observed in some cells containing G1-premature chromosome condensation. When mitotic nuclei were induced to telophase-like nucleus formation, their centrioles were also inactivated. Concomitant events of induced nuclear and centriolar changes suggest that they might have been controlled by the heterophasic cytoplasmic factors through similar pathways.

Animals↗
PubMed1994

[The localization of intermediate filaments in polykaryons in the interphase and mitosis].

Localization of vimentin filaments has been investigated in polykaryons formed by cell fusion in culture of Chinese hamster cells (line Ag17). A network of vimentin filaments was observed around each nucleus of the interphase polykaryons. This compartmentalization of the network persists after beginning of mitoses up to metaphase, both in bipolar and multipolar mitotic cells. The picture of localization of intermediate filaments is most clear in polykaryons with mitotic asynchrony of the nuclei at early stages of mitosis. In anaphase, the central part of the network disappears, and in the polykaryon only peripheral part of the network is observed. The compartmentalization of the network of intermediate filaments is disrupted by such a way. In telophase, bright peripheral fluorescence may by the result of the beginning of network reorganization, and this process will be finished in daughter cells. The role of intermediate filaments in distribution of chromosomes and centrioles between daughter cells during mitosis is discussed.

Animals↗
PubMed1994

[The centriolar complex of heterophasic homokaryons in the interphase and mitosis].

Two patterns of heterophasic centrioles occur in interphase polykaryons obtained by cell fusion: in the form of a united complex, or as groups scattered around the cytoplasm. By the start of mitosis, replication of centrioles is finished. There is no cellular center in polykaryons with mitotic asynchrony of nuclei. In these polykaryons pairs of centrioles are situated near each nucleus. In polykaryons with mitotic asynchrony the spindle forms asynchronously and mainly near condensed chromosomes. At metaphase, the spindles display a complicated multipolar organization. Associated by interpolar microtubules, the spindle poles are not always the nearest to each other and therefore kinetochore microtubules may be directed not to the nearest centrioles. Pairs of centrioles are located at the poles. The problem is discussed of the correlation between the centriole number and polykaryon ploidy, as well as of the role of multipolar mitosis in distribution of centrioles and chromosomes between daughter hybrid cells.

Animals↗
PubMed1991

[The characteristics of the course of mitosis in polykaryons formed during cell fusion].

A new method of cell fusion is proposed utilizing treatment with 15% solution of DMSO in serum before and after PEG treatment. With such treatments in SPEV cell culture a higher rate of cell fusion was obtained than that with other known methods of cell fusion. In the first wave of mitoses (0.5-4 h) mainly asynchronous division of nuclei, premature chromosome condensation and formation of telophase-like nuclei were observed in polykaryons. In the period of the second wave (14-20 h), mitoses were mainly synchronous and completed with cytokinesis. Micronuclei were formed frequently as a result of such mitoses. After the first wave of mitoses the number of polykaryons with pycnotic chromosomes sharply increased, and after the second wave of mitoses the number of polykaryons with pycnotic nuclei increased. The results obtained allow to conclude that heterophasic condition of the fused cells is one of the causes of pathological mitosis of polykaryons and of their death.

Animals↗
PubMed1988

[Ultrastructural disorders of the mitotic apparatus during cytochalasin B action].

A correlation between the number of chromosome sets and the number of centrioles (8n--8 centrioles) was observed in polyploid metaphase cells, during cytochalasin B treatment on the cultured Chinese hamster cells. There is no correlation between the number of chromosome sets and the centriole number after stopping the action of the drug in many cells, but a great variation is observed in maintenance of chromosomes and centrioles (up 6 to 25 n and up 4 to 22 centrioles). In multipolar mitosis, either during the drug action or after its stopping, different numbers of chromosomes are directed towards the poles not depending on the number of centrioles in the poles. During the cytochalasin B treatment, either in bipolar or multipolar metaphases, there are destructions in the ultrastructure of the mitotic apparatus: there are no astral microtubules; in the poles there are diplosomes and duplex of centrioles with fibrillar material around both centrioles; kinetochores are of prometaphase type. After stopping the drug action the astral microtubules appear, but no other patterns of normalization in the mitotic apparatus occur. Desynchronization of three cycles (chromosomal, centriolar and centrosomal) is discussed as a factor of abnormal development of the mitotic apparatus and as a factor of stabilization of aneuploidy in the cell culture.

Animals↗
PubMed1987

[Variants of asynchronous DNA synthesis and mitoses in multinucleate cells induced by cytochalasin B].

Cases of asynchronous progression with separate nuclei of S-period and initial mitotic stages in multinucleate cells were discovered in Chinese hamster cell cultures during a prolonged action of cytochalasin B (7 days) and after its stopping (7 days of cell cultivation without drug). The interphase asynchrony under experimental conditions vary in value corresponding to the level of interphase asynchrony in spontaneous multinucleate cells in control cultures. So, the interphase asynchrony in cytochalasin B-induced multinucleate cells is suggested not to be connected with the drug action. Fusion of heterophase cells and a high level of proliferation activity of multinucleate cells seem to be the main reason of interphase asynchrony both in control cultures and in experimental conditions. Unlike the interphase asynchrony, the appearance of the mitotic asynchrony in multinucleate cells is shown to be connected with the action of cytochalasin B. The high level of the mitotic asynchrony remains after the stopping of drug action. A conclusion is made that mitotic asynchrony of nuclei, along with multipolar mitosis and cytokinesis inhibition, is one more display of the cytotoxic action of cytochalasin B on mitosis.

Animals↗