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PubMed2003

Quantitative investigation of reproduction of gonosomal condensed chromatin during trophoblast cell polyploidization and endoreduplication in the East-European field vole Microtus rossiaemeridionalis.

Simultaneous determinations of DNA content in cell nuclei and condensed chromatin bodies formed by heterochromatized regions of sex chromosomes (gonosomal chromatin bodies, GCB) have been performed in two trophoblast cell populations of the East-European field vole Microtus rossiaemeridionalis: in the proliferative population of trophoblast cells of the junctional zone of placenta and in the secondary giant trophoblast cells. One or two GCBs have been observed in trophoblast cell nuclei of all embryos studied (perhaps both male and female). In the proliferative trophoblast cell population characterized by low ploidy levels (2-16c) and in the highly polyploid population of secondary giant trophoblast cells (32-256c) the total DNA content in GCB increased proportionally to the ploidy level. In individual GCBs the DNA content also rose proportionally to the ploidy level in nuclei both with one and with two GCBs in both trophoblast cell populations. Some increase in percentage of nuclei with 2-3 GCBs was shown in nuclei of the placenta junctional zone; this may be accounted for by genome multiplication via uncompleted mitoses. In nuclei of the secondary giant trophoblast cells (16-256c) the number of GCBs did not exceed 2, and the fraction of nuclei with two GCBs did not increase, which suggests the polytene nature of sex chromosomes in these cells. In all classes of ploidy the DNA content in trophoblast cell nuclei with the single GCB was lower than in nuclei with two and more GCBs. This can indicate that the single GCB in many cases does not derive from fusion of two GCBs. The measurements in individual GCBs suggest that different heterochromatized regions of the X- and Y-chromosome may contribute in GCB formation.

Animals↗
PubMed1997

Polyploid-specific repetitive DNA sequences from triploid ginbuna (Japanese silver crucian carp, Carassius auratus langsdorfi).

Repetitive DNA sequences (Cal3nDr) in the genome of a triploid ginbuna (Carassius auratus langsdorfi) were isolated from the DraI digests of the genomic DNA. This AT-rich (61%) Cal3nDr monomer was 137 bp in length. The nucleotide similarity among the monomers from the same individual was considerably high (above 97%). Hybridization analyses revealed that the Cal3nDr sequences were organized into tandem arrays. These DNA sequences were present only in triploid and tetraploid ginbunas and were absent from diploid ginbuna, gengorobuna, goldfish, and other cyprinid fishes, and therefore appeared to be specific to polyploid ginbunas. In situ hybridization data showed their localization on one to four out of a total of 150 to 156 chromosomes, depending on the individuals or clonal lines, of the triploid ginbuna. The origin of the Cal3nDr sequences is also discussed on the basis of observation of the artificial triploid ginbuna produced by crossing a diploid female with a tetraploid male.

Animals↗
PubMed1975

The recognition and incidence of haploid and polyploid spermatozoa in man, rabbit and mouse.

The existence of polyploid mammalian spermatozoa has been inferred from studies of Feulgen-DNA absorption. Rabbit spermatozoa fell into two discrete groups with mean absorptions close to a 1:2 ratio (inferred to be haploids and diploids respectively); simple visual appraisal of the size of the head or nucleus gave an identical classification. The incidences of ploidy classes were 98-94% haploid, 1-06% diploid, 0-00% higher than diploid (N = 3010; from DNA measurements and visual appraisal of the size in a rabbit chosen to have a high incidence of diploids) and, correspondingly, 99-691%, 0-308%, 0-001% (N = 138001; from sixty-nine unselected rabbits, scored by visual appraisal of the size of the sperm head). In man also, virtually discrete groups with absorptions close to a 1:2 ratio existed and were inferred to be haploids and diploids respectively. A few human spermatozoa were found with absorptions corresponding to a ploidy of three and/or four. Visual appraisal of the size of the human sperm nucleus as Small, Medium or Large was only a partial guide to ploidy. All Small human spermatozoa measured for DNA absorption were found to be haploid. About two-thirds of Medium human spermatozoa were found, however, to be haploid, and some Large spermatozoa were haploid or diploid. The incidences of ploidy classes in the human were 99-37% haploid, 0-56% diploid, 0-07% higher than diploid (N = 5554; with consistency between duplicate slides and between two subjects; from DNA measurements and visual appraisal of nuclear size). The estimated incidence of diploid human spermatozoa is consistent with the known incidence oftriploid fetuses. In a mouse with a putatively high incidence of diploids, all 1000 DNA measurements were nevertheless within the haploid range, with one diploid encountered outside the main sampling.

Animals↗
PubMed2002

Decrease in apoptosis and increase in polyploidization of megakaryocytes by stem cell factor during ex vivo expansion of human cord blood CD34+ cells using thrombopoietin.

Thrombopoietin (TPO) is widely used for ex vivo expansion of hematopoietic stem cells. Previously, we have reported that TPO induces a characteristic pattern of apoptosis, and the TPO-induced apoptosis is closely associated with megakaryocyte (MK) differentiation. In the present study, several cytokines, flt3-ligand, stem cell factor (SCF), interleukin-3 (IL-3), IL-6, IL-11, leukemia inhibitory factor, G-CSF, and erythropoietin, which are known to affect megakaryocytopoiesis, have been evaluated to elucidate their effects on the TPO-induced apoptosis. Measurement of apoptosis by flow cytometry revealed that only SCF absolutely reduced the TPO-induced apoptosis in MK fractions, particularly in the late phase of ex vivo expansion. Platelet production was demonstrated by electron microscopy in a later phase when SCF was added. Simultaneous measurement of DNA contents with immunophenotyping demonstrated a significant increase in polyploidization in the CD41+ cell fraction when cultured with SCF. These results suggested that SCF not only inhibited premature senescence but also enhanced maturation of the differentiating cells of MK lineage during ex vivo expansion using TPO.

Antigens, CD34↗
PubMedDate not supplied

[Biological effects in natural populations of small rodents in radiation contaminated areas. The frequency of bone marrow polyploid cells of bank voles in different years following Chernobyl accident].

On the basis of the metaphase analysis results, the peculiarities of dynamics of the genome mutation frequency (polyploid cells) were studied in bone marrow of bank voles inhabiting the areas with different radiocontamination level due to the Chernobyl accident (8-1526 kBq/m2 for 137Cs) in 1986-1991. Unexpectedly high frequencies of polypoid cells exceeding the pre-accidental level by a factor of 10(1)-10(3) were recorded in all populations studied. Relationship between the frequency of the parameter studied and the concentration of radionuclides incorporated in animal carcasses was proved. A statistically significant rise in the frequency of genome mutations with the time was revealed up to 1991, i.e. approximately to 12th post-accidental animal generation.

Animals↗
PubMedDate not supplied

Polyploidization induced by acridine orange in mouse osteosarcoma cells.

This study was undertaken to clarify the in vitro effect of acridine orange (AO) on the cell kinetics of mouse osteosarcoma cells, as well as the mechanism of cell growth inhibition induced by AO. A mouse osteosarcoma cell line (MOS), established from a radiation-induced mouse osteosarcoma, was cultured under exposure to 0.05, 0.5, 5, and 50 micrograms/ml of AO, either continuously or for 10 minutes. The cell kinetic analysis was performed using the following parameters: tumor cell growth by trypan blue exclusion test, mitotic activity, DNA synthetic activity by BrdU labeling and DNA ploidy by cytofluorometry. The results showed that continuous exposure to 5 and 50 micrograms/ml of AO or 10 minute exposure to 50 micrograms/ml of AO quickly killed the tumor cells within 12 hours, whereas continuous exposure to 0.5 microgram/ml of AO or 10 minute exposure to 5 micrograms/ml of AO gradually inhibited tumor cell growth. Under the latter conditions, mitotic activity was rapidly and completely inhibited within 48 hours but DNA synthetic activity was not completely inhibited even after 96 hours. DNA ploidy analysis demonstrated that most of the tumor cells arrested at the S-G2 phase after 12 hours, followed by G2 phase arrest after 24 hours and progressive DNA synthesis to a higher DNA ploidy class after 48 to 96 hours. We therefore concluded that a high concentration of AO has a strong cytocidal effect due to cytotoxicity whilst a moderate concentration of AO induces progressive and synchronous polyploidization by mitotic inhibition without DNA damage in MOS cells. We presume that this in vitro effect on MOS cells may be caused by protein synthetic inhibition after transfer RNA inactivation caused by AO binding.

Acridine Orange↗
PubMed2000

Dynamics of structural and functional association of nucleolar chromosomes in cells of the hexaploid wheat Triticum aestivum L. at different stages of the cell cycle and during genome polyploidization.

Quantitative analysis of interphase association of the nucleolar chromosomes at different stages of the cell cycle and during genome polyploidization was carried out. Cells of various tissues of hexaploid wheat Triticum aestivum L. (Moskovskaya-35) were used, including diploid root meristematic cells, endopolyploid root cells, triploid endosperm cells and antipodal cells with polytene chromosomes. Interphase nucleoli impregnated with silver or stained with autoimmune antibodies to 53 kDa nucleolar protein served as markers of the nucleolar chromosome association. The following data were obtained: (1) silver-staining revealed two pairs of homologous chromosomes 1B and 6B with active nucleolus-organizing regions in the root meristematic cells; (2) maximal number of nucleoli in diploid meristematic cells reaches four, which corresponds to the number of chromosomes with active organizers; (3) analysis of cells at different stages of the cell cycle has shown that the tendency to the nucleoli association is observed as soon as cells pass individual stages of the cycle; (4) after DNA and chromosome reduplication, the nucleolus-organizing regions in sister chromatids function as a common structure-functional complex; (5) in endopolyploid root cells and antipodal cells with polytene chromosomes, the number of nucleoli does not correlate with ploidy level, and an additional nucleolus revealed in some cells is the result of activation of the latent organizer in one of the nucleolar chromosomes; (6) in the triploid endosperm nucleologenesis, the stage of prenucleolar bodies is missing. Our data suggest that "fusion" of nucleoli and reduction of their number due to the "satellite" association of the nucleolar chromosomes are two independent processes regulated by different mechanisms.

Cell Cycle↗
PubMed1975

[Basic factors in the polyploidization of cerebellar Purkinfe cells in chick embryogenesis. III. Kinetics of RNA and DNA in Purkinje cell nuclei].

The content and concentration of RNA and DNA in the nuclei of the Purkinje cells of cerebellum of chick embryos (10-21 day-old) were determined by cytospectrophotometry. The RNA concentration shows a dayly rhythm, its content significantly increasing. The periods of the increase of RNA synthesis coincide with the periodicity of protein synthesis, the morphogenesis of the Purkinje cells and with the embryo's development as a whole. The DNA concentration remaining constant, its content increases sharply with the onset of the specific functional activity of cells and of the intensive growth of axons and dendrites. The variability of the mean values of this growth increases which is conditioned by the appearance of cells with hyperdiploid, tetraploid and hypertetraploid DNA contents in their nuclei. The Purkinje cells do not divide, their increased DNA content may be regarded as the expression of polyploidization or polytenization (which are functionaly equivalent) of a part of the nuclei. It is not excluded that in this case a differential gene amplification may take place. The increase of DNA content is associated with the onset of morphofunctional maturity of cells and may be due to a continuously increasing intensity of protein synthesis secured by the matrix material.

Animals↗
PubMedDate not supplied

[Changes in the content of different nuclear proteins and DNA from diploid and polyploid hepatocytes in regenerating liver of mice].

The content of 4 fractions of nuclear proteins (histones, acid chromatin protein, globulins and chromatin-free acid protein) in diploid and polyploid hepatocytes from intact and regenerating liver of mice is studied. These types of nuclei are found to differ in the protein content and in the protein/DNA ratio. Synthesis of all classes of nuclear proteins was intensified at the G1-stage, and synthesis of DNP non-histone proteins at the end of S- and G2-stage. Possible role of different nuclear proteins in the regulation of cell multiplication is discussed.

Animals↗
PubMed2002

[Quantitative investigation of reproduction of condensed chromatin of sex chromosomes during trophoblast cell polyploidization and endoreduplication in the East European field vole Microtus rossiaemeridionalis].

Simultaneous measurement of DNA content in cell nuclei and condensed chromatin bodies formed by heterochromatized regions of sex chromosomes (gonosomal chromatin bodies, GCB) has been performed in two trophoblast cell populations of the East-european field vole Microtus rossiaemeridionalis, namely in the proliferative population of trophoblast cells of the junctional zone of placenta and in the secondary giant trophoblast cells. One or two gonosomal chromatin bodies have been observed in trophoblast cell nuclei of all embryos studied (perhaps both male and female), In the proliferative trophoblast cell population, characterized by low ploidy levels (2c-16c), and in the highly polyploid population of secondary giant trophoblast cells (16c-256c), the total DNA content in GCB increased proportionally to the ploidy level. In separate bodies, the DNA content rose also in direct proportion with the ploidy level seen in the nuclei with both one and two GCBs in the two trophoblast cell populations. A certain increase in percentage of the nuclei with 2-3 GCBs was shown in the nuclei of the junctional zone of placenta; this may be accounted for by genome multiplication via uncompleted mitoses. In the secondary giant trophoblast cell nuclei (16c-256c), the number of GCBs did not exceed 2, and the share of nuclei with two GCBs did not increase, thus suggesting the polytene nature of sex chromosome in these cells. At different poloidy levels, the ratio of DNA content in the nucleus to the total DNA content in GCB did not change significantly giving evidence of a regular replication of sex chromosomes in each cycle of genome reproduction. In all classes of ploidy, the mean total DNA content in trophoblast cell nuclei with single heterochromatic body was less than in the nuclei with two and more GCBs. This may indicate that a single GCB in many cases does not derive from the fusion of two GCBs. To put it another way, in the nuclei with one GCB and in those with two or more GCBs, different chromosome regions may undergo heterochromatization. The regularities observed here are, most probably, associated with the peculiarities in the structure of X- and Y-chromosomes in a range of species of Microtus (M. agrestis, M. rossiaemeridionalis, M. transcaspicus). As a result, gonosomal chromatin bodies may include large blocks of both constitutive heterochromatin of X- and Y-chromosomes (in male and female embryos) and inactivated euchromatin of "lyonized" X-chromosome in female embryos. Therefore the presence of two or more GCBs in trophoblast cells of M. rossiaemeridionalis may be accounted for by both polyploidy and functional state of the nucleus, in which gonosomal constitutive heterochromatin and inactivated euchromatin form two large chromocenters rather than one. The differences in DNA content in GCBs in the nuclei with one and two GCBs seem to be an indirect indication that the two chromocenters may be formed by two different gonosomes, with the extent of their heterochromatization being higher than that in the nuclei with one GCB. GCBs in the trophoblast cells of M. rossiaemeridionalis are observed not only at the early developmental stages, as it was observed in rat at the first half of pregnancy (Zybina and Mosjan, 1967), but also at the later stages, up to the 17th day of gestation. At these stages, the nuclei with non-classical polytene chromosomes rearrange to those with a great number of endochromosomes, probably because of disintegration of chromosomes into oligotene fibrils. However, it does not seem unlikely that this process may involve heterochromatized gonosomal bodies, since only one or two large GCBs can be seen in the nuclei as before. The presence of prominent blocks of constitutive heterochromatin seems to favor a closer association of sister chromatids in polytene chromosomes, which prevents their dissociation into endochromosomes with the result that polyteny of sex chromosomes in the field vole trophoblast is probably retained during a longer period of embryonic development.

Animals↗
PubMed1992

Ultrastructure and biosynthetic activity of polyploid atrial myocytes in patients with mitral valve disease.

Biopsies of right auricle of human heart have been obtained during open heart surgery from 6 patients aged 23 to 49. The DNA and total protein content have been determined in isolated myocytes by two-wavelength scanning cytophotometry after double staining: Feulgen and naphthol yellow S. In all the biopsies predominant are polyploid hypertrophied myocytes. Both hypertrophied non-degenerating cells and cells with different extent of degenerative changes, primarily of myofibrils and membranes, are present. The highest extent of cell ploidy is in patients belonging to functional class IV according to the classification of New York Heart Association (NYHA); in these cases 72 to 98% of cells have nuclei with 8 c and more DNA content. With an increase in ploidy level, cells grow in size and in protein content, however the rate of this growth is much lower than that of DNA content in cells. There is no direct relation between ploidy and cell degeneration extent and no inverse relation between degeneration extent and ejection fraction.

Adult↗
PubMed1991

DNA-cytometric detection of euploid polyploidization in oral lichen ruber planus.

The DNA distribution was analyzed in 29 cases of oral lichen ruber planus that were negative for human papillomavirus and not suspected of being precancerous. Monolayer smears prepared from formalin-fixed, paraffin-embedded tissues were automatically Feulgen stained and used for rapid interactive DNA cytometry via a TV-based image analysis system combined with an automated microscope. Nuclei with DNA contents greater than 4c were found in 25 cases (86%). DNA contents greater than 8c were seen in five cases (17%), and small peaks at 8c were found in three cases. These increased DNA values in nonprecancerous lesions must be interpreted as euploid polyploidization and have to be taken into account if DNA measurements are performed for diagnostic purposes in lichen ruber planus lesions that are suspected of having malignant transformation.

DNA↗
PubMed1991

[Nuclear DNA contents in the cells of squamous cell carcinoma. III. Separation and analysis of polyploid cells].

In order to reveal the cytological nature of polyploid cells, the cell suspension of squamous cell carcinoma was separated into low density (1.050 greater than), intermediate density (1.050 to 1.088), and high density (1.988 greater than) fractions, by density gradient centrifugation. The DNA content of the tumor cells in each fraction were measured on the smear specimens prepared by Giemsa's staining and Feulgen's stainings. As the results, it was found that the cells showing high NC ratio and having high DNA content were observed in the high density fraction. However, there was no specific relationship between the nuclear contour index and density of the tumor cell.

Aged↗
PubMed1990

[N-terminal sequence of omega-gliadins from Aegilops longissima. The origin of the genome of polyploid wheat].

Using high-performance reversed phase liquid chromatography, the major components of omega-gliadins were isolated from four samples of Aegilops longissima. A high interspecific variability of Ae. longissima with regard to gliadin composition was demonstrated. The N-terminal sequences of omega-gliadins were determined. It was shown that omega-gliadins under study belong to the SRQ type earlier discovered in hexaploid wheat species and in Ae. squarrosa. It is supposed that this type of sequence is specific to the whole Aegilops genus. The N-terminal sequence of omega-gliadin of Ae. longissima was identified and its similarity to the alpha/beta-type sequence found in hexaploid wheat species was revealed. The data obtained are discussed in terms of the origin of polyploid wheat genomes.

Amino Acid Sequence↗
PubMed1987

[Polyploidization dynamics of tertiary trophoblast giant cells in the rat placenta].

Polyploidization peculiarities of tertiary giant trophoblast cells during their active detaching from the ectoplacental cone and migrating into decidua basalis are investigated. On the 12th day of gestation, the ploidy of the majority of cell nuclei varies within 4-8c, although there are a few 16c and 32c nuclei. On the 13th and 14th days of gestation, the ploidy level of tertiary giant trophoblast cells enhances; 8c and 16c nuclei prevail, the percentage of 32c nuclei increases, 64c nuclei arising. The ploidy level of tertiary giant cell coincides with the average and/or maximum ploidy degree of precursor cell populations. The significance of polyploidy as indispensable condition of differentiation of the trophoblast cells that actively invade into maternal tissues is discussed.

Animals↗
PubMedDate not supplied

[More active synthesis of the polysaccharide, pullulan, by polyploid cultures of Pullularia pullulans].

The polyploid strains of Pullularia pullulans differ from each other and from the haploid strain in the amount of the polysaccharide pullulan liberated into the cultural broth. The highest pullulan synthesizing activity (per unit of the assimilated carbon source and the synthesized biomass) was manifested by the diploid strain of P. pullulans 1125(13) whose cells produced more pullulan (by 75%) within three days of growth than the cells of the haploid culture. The content of pullulan calculated per unit area of the cell surface increased with the level of ploidy: 1.5-1.8 times in the diploid cultures and 3.4 times in the tetraploid culture cf. the parent haploid culture. Apparently, the polyploidy of the P. pullulans culture was accompanied with mutations involved in the synthesis of the extracellular polysaccharide.

Culture Media↗
PubMedDate not supplied

[Polyploidization of rat hepatocytes induced by x-ray radiation at different periods of the cell cycle].

As determined by the yield of polyploid hepatocytes after X-irradiation of rats with a dose of 6 Gy the S-stage of the cell cycle was most radiosensitive; as to the yield of cells with chromosome aberrations the middle of the G1-stage was the most radiosensitive period of the cell cycle. The differences in the radiosensitivity of the cell cycle stages indicated that although primary lesions were similar molecular mechanisms leading to tre final effect were essentially different.

Animals↗