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PubMedDate not supplied

[Polyploid hybrids of industrial yeast races and the prospects for using them in production].

The ploidity of the parent forms, hybrids, and two industrial yeast races was studied by determining the content of DNA per cell, the ratios during allel splitting, the dimensions and volumes of the cells. The triploid nature of the baker's race 14--2 and some hybrids was found (for example, the productive hybrid 112 obtained by crossing the distillery and baker's races). The results obtained suggest the possibility to apply the techniques of hybridization and polyploidy for selecting productive yeast strains.

Alleles↗
PubMed1975

[Effect of ultraviolet light on human chromosomes (author's transl)].

Lymphocytes were cultured in quartz flasks and irradiated by UV light. Time of exposure and moment of application varied. After UV treatment, pulverization of the chromosomes occurred and larger nuclear fragments which might be products of an abnormally proceeding mitosis with chromatin confluence were observed. The usual chromosome aberrations such as breaks, special segments, abnormal chromosomes and polyploidy have been rarely observed, but are found more often in those cultures where pulverization and nuclear fragments are less abundant. A number of mitoses in the irradiated cultures, however, shows no chromosomal aberrations. The ratio of unaffected to unaffected mitoses is dose-dependent. Chromosome fragmentation can result from UV irradiation occurring at any instance during the time of culture. One finds maximum and minimum amounts of damage when a constant dose is applied at various times.

Cell Nucleus↗
PubMed2001

[Morphofunctional parameters of the nucleoli during development of polyploid nutrient cells of gonads from the snail Succinea lauta].

Ag-protein contents, integral area and number of nucleoli in polyploidizing nuclei of gonadal nutrient cells of the snail Succinea lauta were estimated on the squashed preparations by means of morphometry and cytophotometry. 8 NORs of different size were found in haploid chromosome set of prophase spermatocytes (n = 22), but usually 1-2 nucleoli per 2c DNA are present in the nutrient cell nuclei. During genome multiplication from 2c to 32c-64c the Ag-proteins content of nucleoli increased proportionally to gene dosage, but irregularly: before 8c-level the coefficient of increasing in each endocycle was more than 2; from 8c to 16c it was 2; after 16c-level it usually decreased to 1.6-1.3. This dynamics reflects the effects of several factors on nucleolar activity: endomitotic polyploidy (gene dosage effect), differentiation and rhythmic functioning of tissue. Increasing indexes of integral area and the number of nucleoli during polyploidization were significantly less, than increasing index of Ag-proteins. The lag of nucleolar area for 4 cycles (2c-32c) was 32%, and number of nucleoli per diploid set decreased from 2 to 1. It may be due to NOR aggregation corresponding chromosomes. The photometric index of Ag-protein content more adequately reflects in the nucleolar activity during development and functioning of tissues.

Animals↗
PubMed1975

Comparative effects of three nitrosourea derivatives on mammalian cell cycle progression.

Three nitrosourea analogs, 1,3-bis(2-chloroethyl)-1-nitrosourea, 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea, and 1-trans-(2-chloroethyl)-3-cyclohexyl-1-(4-methylcyclohexyl)-1-nitrosourea, were examined for effects on survival and cell cycle traverse capacity in exponentially growing (cycling) populations of line CHO Chinese hamster cells and in cultures arrested in G1 by isoleucine deprivation during treatment with drugs, then returned to the cycling mode by restoration of isoleucine (noncycling cells). Among parameters studied were survival, cell division, DNA initiation capacities, cell cycle distributions, and rates of cell cycle traverse in drug-treated cycling and noncycling cells utilizing a protocol combining autoradiography, cell number enumeration, and flow microfluorometry. The results obtained were in generally good agreement with results obtained in vivo in other studies and included the following. Cells treated with any of these agents accumulated preferentially in late S and G2, primarily the result of a gross increase in duration of these phases of the cell cycle. There was also a prolongation of doubling time during the early stages following drug treatment and return to the proliferating mode of cells which ultimately survived. All three drugs induced mitotic nondisjunction in cells capable of dividing and also induced polyploidy by allowing multiple rounds of progression through the cell cycle in the absence of an intervening cell division. In treated populations, the G2-arrested and polyploid cells were among the first cells to die. Treated, noncycling cells that were returned to cycle exhibited a lower survival capacity than did treated, cycling cells. Finally, 1-(2-chloroethyl-3-cyclohexyl)-1-nitrosourea and 1-trans(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea induced a dramatic alteration in clonal morphology and growth patterns in surviving cells that persisted for at least a week after drug removal. The results obtained suggest that our model system may be useful as a predictive guide for determining response of susceptible tumor cells to treatment with chemotherapeutic agents.

Animals↗
PubMed1975

Cultivated cells from diagnostic amniocentesis in second trimester pregnancies. II. Cytogenetic parameters as functions of clonal type and preparative technique.

From a total of 418 primary amniotic fluid colonies, 5.5% were fibroblast-like (F), 33.7% epithelioid (E) and 60.8% had characteristics of what was previously shown to be the principal class of clonable amniotic fluid cells (AF). Polyploidy occurred in all three categories, although both pure tetraploidy and mixoploidy were more frequent in E colonies. The incidence of non-constitutional chromosomal changes was identical in AF and E type colonies if primary spreads were analyzed in situ without prior trypsinization. Spreads from pooled cell suspensions showed higher base-line levels of both aneuploidy and structural changes. Analysis of individual colonies employing an in situ preparative technique is clearly the method of choice for a reliable cytogenetic prenatal diagnosis within the shortest possible period of time.

Amniocentesis↗
PubMed2002

Characteristics of mitotic cell death induced by enediyne antibiotic lidamycin in human epithelial tumor cells.

Mitotic cell death, a different cell death mode from apoptosis, has been focused on in tumor therapy. It may involve the mechanism of highly potent cytotoxicities of enediyne antibiotics toward tumor cells. We describe the characteristics of mitotic cell death induced by enediyne antibiotic lidamycin at low concentrations (0.01-1 nM), in the human hepatoma BEL-7402 cells and human breast carcinoma MCF-7 cells. The cells exerting mitotic cell death showed retardation at G2+M phase, enlargement of cell volume and multinucleation, some of which were positive in senescence-associate beta-galactosidase staining. The multinucleated living cells did not show apoptotic features by co-staining with mitochondria-specific dye Mitosensor and DNA-specific dye Hoechst 33342. The DNA polyploidy rather than increased with incubation time for the lidamycin-treated BEL-7402 cells. The proliferation status of BEL-7402 cells was shown by flow cytometry after the cells were labeled with PKH-67, a fluorescent dye for labeling living cells, but the fluorescent intensity of the lidamycin-treated cells was little changed. The smear DNA pattern was detected in the multinucleated cells by agarose gel electrophoresis. The results provide the first evidence for elucidating the potent cytotoxicities of lidamycin toward tumor cells and further describing characteristics of mitotic cell death.

Aminoglycosides↗
PubMed2002

[Genetic structure of a diploid-polyploid complex of the spined loach Cobitis taenia (Cypriniformes: Cobitidae) from the middle Dnieper bassin].

Biochemical genetic typing and cytometry showed that polyploid females account for 87% of the spined loach Cobitis taenia population from the middle Dnieper basin. The polyploidy series included triploids, tetraploids, and, possibly, a few pentaploids. A characteristic feature of the genetic structure of polyploids was that their genetic variation was due to the clonal variation in the haploid portion of the genome originating from Cobitis sp. and to polymorphism of the diploid portion originating from C. taenia. The results are discussed with regard to comparative evolution of alloploid complexes in fish and terrestrial vertebrates.

Animals↗
PubMed1975

[In vitro induction of numerical changes in the karyotype of normal and transformed cells of Dzhungarian and Chinese hamsters].

The comparative study of the frequency of colcemid-induced aneuploidy and polyploidy in cultured normal and transformed cells of Djungarian hamster is described. The occurrence of variants with changed chromosome number is much higher in populations of SV40-transformed cell line (4/21) than in normal embryonic cultures. In transformed lines of Djungarian and Chinese hamsters (4/21 and V-79) the frequency of cells with changed chromosome number was found to be depend on the culture density: the percentage of polyploids was 4-5-fold higher when the number of seeded cells was 2-fold lower. The highest number (18-29%) of hypermodal cells was produced at drug concentrations of 0.02--0.025 mkg/ml. The percentage of polyploids under these conditions reached 10--20. At further increaseof colcemid concentrations the proportion of polyploid cells increased. In Djungarian hamster embryonic cell cultures there were single cells with changed chromosome numbers at a concentrarion of the drug of 0.015-0.1 mkg/ml.

Animals↗
PubMed2002

[Morphofunctional parameters of nucleoli during development of the albumen gland polyploid cells in the snail Succinea lauta].

Ag-protein content, the total area and the number of nucleoli were estimated on AgNO3-methyl green stained squashed preparations of the albumen gland of Succinea lauta during polyploidization, differentiation and functioning of secretory cells. The investigation was made by means of morphometry and cytophotometry using the computer videoimage system. During the gland growth, the mean number of nucleoli increased from 1-2 in diploid (2c) nuclei to 3 in polyploid (16c-32c) nuclei, but commonly only one large nucleolus was formed in mature nuclei. As a whole, the area and Ag-protein content of nucleoli was changed proportionally to the gene dosage, but this dependence was not linear during several endocycles. Before 8c-level the coefficients of increase in each endocycle were more than 2 (2.7-4.0), and these decreased to 1.5-1.0 during the following endocycles (8c-16c-32c). The area of nucleoli increased more quickly than Ag-protein content in the course of endocycles of growing cells. On the contrary, a relative area of nucleoli decreased with the increase in ploidy levels in mature cells. This irregular dynamics reflects the influence of several factors of the nucleolar activity: endomitotic polyploidy (gene dosage effect), cell differentiation, inhibition of transcription, and its reactivation in mature cells. In addition, individual variations of nucleolar parameters in mature snails are associated with the rhythmical functioning of sexual system, and aging of animals.

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↗
PubMed2002

[Morphofunctional changes in hepatocytes during the early postnatal development of rats experimentally infected with the intestinal protozoan pathogen, Cryptosporidium parvum (Coccidia, Sporozoa)].

Morphofunctional changes in hepatocytes of 10-14-day old rats were followed in norm and after experimental infection with different doses of oocysts of Cryptosporidium parvum. The liver index (ratio between the liver and body masses) varied with the intensity of invasion on the background of slowing down up to the total cessation of animal growth rates, and all this obviously pointed to severe pathology. In the infected rats, some cytological indices were shifted compared to the norm: protein amount and the average number of genomes per hepatocyte were seen to increase, the normal ratio between cells with different ploidy levels being violated. The particular correlation analysis was employed to distinguish between the ontogenetic (animal growth related) and pathologic (related to the infection intensity) polyploidization and hypertrophy in hepatocytes. In 10-14-day old rats, the former is affected primarily by the increase in the share of multinuclear hepatocytes, whereas the latter is accomplished by the increase in the number of cells with polyploid nuclei (4c and 4c x 2 cells). In the heavily infected rats, the ontogenetic polyploidy was almost totally suppressed due, presumably, to their growth rate inhibition, the rise in hepatocyte ploidy resulting form the obvious pathological changes in the liver. In the infected rats, the ontogenetic hypertrophy of hepatic parenchymatous cells was not manifested, and the observed protein accumulation in hepatocytes also resulted from the pathological changes in the liver. It is obvious that changes in cell hypertrophy (protein content) may serve as a more susceptible tool that readily perceives the host's stress experienced due to the parasitic infection (cryptosporidiosis), than cell ploidy: the levels of the respective responses of these two parameters differing by 4 times. However, due to the known reversible nature of hypertrophy, it cannot be used for the aims of a long-term prediction about the future mode of liver functioning in the animal that survived cryptosporidiosis. Unlike, such a parameter as frequencies of hepatocytes with different ploidy levels is much more useful in this respect.

Animals↗
PubMed1976

[Analysis of DNA histograms by computer (author's transl)].

INTRODUCTION: Quantitative DNA cytophotometry, the study of morphology of chromosomes and cell kinetics are important approaches toward characterization of genetic information. Each approach has its own problems and limits. Difficulties with interpretation of DNA histograms arise from a lack of proper terminology, and from attempting to interpret them in terms of the existing terminologies for chromosomal analysis and cell kinetics. Aim of this research was to develop a computerized mathematical analysis of DNA histograms. MATERIALS AND METHODS: As a basis for the comparison of normal with those of tumor cell populations the DNA histograms of heart muscle cells were selected for the normal cell population from 14 normal hearts of adults, 16 hypertrophic hearts, 14 non-polyploidized hearts of children, and 14 hypertrophic hearts of children with congenital malformations. Normal diploid cell populations from 7 effusions were also included. The 24 populations of malignant cells consisted of primary tumors and metastatic effusions. DNA cytophotometry was performed on single nuclei in Feulgen stained preparations by means of the UMSP/XD 50 ZEISS. The approximation of the DNA histograms by linear combination of normal distributions was done according to spline-function and calculated by means of the IBM-375. RESULTS: The nuclear classes 2C, 4C, and 8C show no differences between the normal, left and right heart with respect to mean values (X), standard deviations (sx), variances (sX) and coefficients of variance (sx/X). However, coefficients of variance are smaller in hypertrophic (2.15 to 8.37%) than in normal hearts of adults (8.90 to 10.85%), and larger in hypertrophic heart of children (4.06 to 7.09%). The mean values of the DNA classes 2C, 4C, 8C, and 16C vary witin +/- 18.6% with a probability of 95.5%. Benign effusions contain only 2C and 4C nuclei with a variance of 4.00% and 8.75%, respectively. In DNA histograms of malignant cells, only one third has a first peak outside of 2C +/- 18.6%. In approximately one fifth of the histrograms the position of the second or third peaks deviates significantly from normal polyploid values. Since a large proportion of polyploid nuclei is limited to only a few normal tissues, pronounced polyploidy is suggestive of malignancy in all other tissues. If in the cases containing only two DNA classes, 2C and 4C, the populations are malignant, the proportion of 4C is more than 8% while in the corresponding benign populations the proportion of 4C atains only 2.97 +/- 2.5%. In some cases a few highly polyploidized nuclei not taken into a account by our computer program are suggestive of malignancy. In only one DNA histogram out of the 24 analysed, all of these criteria are negative. In six cases the computer analyses reveal two stemlines of tumor cells with corresponding polyploid values.

Adult↗
PubMed1962

Chromosomes of leukocytes. The problem of human individuality.

The technique of chromosome analysis of human leukocytes after short periods of culture in vitro gives promise in several areas of basic biology and medicine. Information is being accumulated on the possibility that stem-line cells in the circulation can assume hemopoietic function. A large number of congenital diseases are being described in terms of chromosomal aberrations. Human blood cells are found to be useful in the study of radiation, air pollution and drug injuries. It is possible that this method may also be helpful in evaluating various cancer therapeutic measures. Basic information is needed to assemble tables of constants regarding variation in the range of modal chromosome numbers (aneuploidy), as well as the occurrence of polyploidy and injury in presumably healthy persons.

Aneuploidy↗
PubMed2003

Overexpression of the oncogenic kinase Pim-1 leads to genomic instability.

Aneuploidy and chromosomal aberrations are hallmarks of most human epithelial malignancies. Here we show that overexpression of the oncogenic kinase Pim-1 in human prostate epithelial cells induces genomic instability by subverting the mitotic spindle checkpoint. Cells overexpressing Pim-1 have a defect in the mitotic spindle checkpoint, abnormal mitotic spindles, centrosome amplification, and chromosome missegregation. Polyploidy and aneuploidy ensue due to a delay in completing cytokinesis. These results define a novel role for elevated Pim-1 expression in promoting genomic instability in human prostate tumors.

Cell Cycle↗
PubMed2004

Evolution of triploidy in Apios americana (Leguminosae) revealed by genealogical analysis of the histone H3-D gene.

Autotriploidy is normally considered to be maladaptive in plants because of its association with high levels of sterility. Nonetheless, triploid individuals are found in many plant species and play important roles in plant evolution, in particular as a first step toward tetraploid formation. However, few studies have addressed the evolutionary potential of triploid lineages, which may principally suffer from the impossibility of combining useful mutations in a single genome due to their low fertility. Therefore, triploids acquire genetic diversity only via recurrent evolution and somaclonal mutation. This study evaluates the potential of multiple origins of polyploidy as a source of genetic diversity in Apios americana, a North American legume that possesses both diploid and triploid populations. Ploidy level determination via flow cytometry shows that triploids are mainly restricted to the portion of eastern North America that was covered by ice during the Wisconsinan glaciation 18,000 years ago. This distribution implies that either selection or postglaciation colonization played a role in shaping this cytogeographic pattern. A haplotype network of the single copy nuclear histone H3-D gene reconstructed using statistical parsimony, together with single-strand conformational polymorphism analysis, shows that autotriploidy evolved at least three times in this species and that heterozygosity is high in triploids. The genetic diversity found in A. americana resulting from recurrent evolution and fixed heterozygosity increases the likelihood of producing successful genotypes and may give the opportunity for triploids to be better fit than diploids in new habitats. This suggests that triploid lineages can exhibit evolutionary potential of their own, and do not serve solely as a first step toward tetraploid formation.

DNA Primers↗
PubMedDate not supplied

[Epigenetic and synergistic types of inheritance of the reproductive characters in angiosperms].

The author considers three types of hereditary memory (structural, cell and signal), that are realized on different levels of biological organization. These three types of hereditary memory correspond to three types of reproduction: self-replication, cell division and reproduction s. str. Reproductive characters are exemplified with three essential characters in angiosperm plants: dimorphism in population by flower sex; mono-, di- and trystyly of flowers; uni- and biparental mode of seed reproduction. All these characters are considered as "supercharacters" that are controlled by gene ensembles. The correspondence between three types of reproduction and three types of hereditary memory are discussed. The authors reviews also the role of polyploidy (auto- and endoploidy) in the inheritance of reproductive condition. From the information theory point the increase in cell ploidy causes the growth of uncertainty in expression of genes and gene ensembles thus creating new type of variability--epigenetic variation. The change of reproductive strategy in plants is regulated by state of gene and gene ensembles and does not demand structural changes in genome. The reproductive characters of plants in spite its complex structure are inherited in number of generations as a discrete Mendel characters by mono-, di-, ot trihybrid schemas.

Biological Evolution↗
PubMed2004

[Antiproliferative effect of bcl-2 gene does not concern the control of mitotic events].

E1A + c-Ha-ras-transformants overexpressing bcl-2 oncogene are able to be arrested at the G1/S boundary of the cell cycle after DNA damage and upon serum starvation, this cell cycle blockage being accompanied by a decrease in the activity of cyclin E--Cdk2 complexes. Roscovitine-induced inhibition of cyclin-dependent kinases (Cdks) activity does not result in the G1/S arrest of E1A + c-Ha-ras + bcl-2-transformants. Roscovitine treatment causes an accumulation of G2/M cells, mainly at the expense of mitotic cells. However, the expression of Bcl-2 oncoproducts does not re-establish the regulation of mitotic events broken by introduction of E1A and c-Ha-ras oncogenes in normal cells, as revealed by the treatment of E1A + c-Ha-ras + bcl-2-transformants with nocodazole inducing mitotic arrest in normal cells. In spite of the elevated expression of antiapoptotic bcl-2 gene in transformants, nocodazole treatment results in mass apoptotic death preceded by polyploidy. Roscovitine also induces apoptosis with no polyploid cell accumulation being observed. Inhibition of Cdks activity with Roscovitine, as well as violation of microtubule depolymerization with nocodazole result in the apoptotic death in the tested cell lines sensitive (E1A + c-Ha-ras) and resistant (E1A + c-Ha-ras + bcl-2) to damaging agents. Thus, the application of Roscovitine, a specific inhibitor of Cdks, suggests that the decrease in Cdks activity in E1A + c-Ha-ras + bcl-2-transformants is not likely to be responsible for G1/S cell cycle arrest realization after damaging influences. Moreover, an antiproliferative effect of Bcl-2 in E1A + c-Ha-ras-transformants is restricted by restoration of cell cycle events at G1/S and G2/M boundaries, and does not concern the program of mitotic events regulation.

Adenovirus E1A Proteins↗