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PubMed1997

[Correlation between the level of polyploidy and hypertrophy and degree of human atrial cardiomyocyte damage in certain congenital and acquired heart pathologies].

Cardiomyocytes of right auricle of human heart were obtained during open heart surgery from 5 patients (aged from 3.6 to 6 years) with congenital heart diseases (atrial septal defect and tetralogy of Fallot, group I), from 6 patients (aged from 20 to 49 years) with mitral valve disease (group II) and from 5 patients (aged from 40 to 54 years) with ischemic heart disease (group III). Ploidy and area of cells were measured in isolated myocytes after the Feulgen staining. The degree of ultrastructural changes in myocytes was evaluated by means of scoring system (0 to 3). The hearts of group I patients contain 55 to 82% of cells with 2c DNA, 18 to 41% of cells with 4c DNA and 0 to 4% of cells with 8c DNA. In the hearts of group II patients the level of cell ploidy is high: the share of 2c-cells varies from 1 to 24%, that of 4c-cells--from 1 to 55%, that of 8c-cells--from 13 to 57%, that of 16c-cells--from 1 to 39%, the share of cells with 32c and more DNA--from 3 to 47%. The ploidy of myocytes of group III patients is not high: 2c-cells make 35 to 55%, 4c-cells--39 to 55%, 8c-cells--5 to 15%. The average cell areas in group II are 4 times larger than in group I, and twice as large as in group III. In most cases, cells of all ploidy levels are larger in patients with higher average cell sizes. In all patients with increased ploidy levels, cells grow in size, but the rate of this growth is lower than that of cell DNA content. In all patients the myocytes with different degrees of organelle damage are observed. In patients of groups I and III there is a direct correlation between the extent of myocyte ploidy and hypertrophy, on the one hand, and the degree of cell degeneration, on the other hand. In contrast, in group II patients an inverse relation between ploidy and extent of degenerative changes of cells is evident.

Adult↗
PubMed1984

Flow cytometric analysis of mouse hepatocyte ploidy. II. The development of polyploidy pattern in four mice strains with different life spans.

The development of liver ploidy in mice aged up to 24 months was investigated by flow cytometry in four mouse strains. A mathematical procedure was applied for correction of flow cytometry histograms. In two of the mouse strains, C3H and DBA, both cellular and nuclear ploidy proceed in the same way. The octoploid cell with two tetraploid nuclei is the most numerous cell type in adulthood. On the other hand, strain NZB and the out-bred strain NMRI show at the corresponding age a higher proportion of diploid cells with strikingly low proportions of 4c cells. In addition, high values of 16c cells and nuclei are present in NMRI. In all strains the proportion of binucleate hepatocytes is in the same range (60%). However, the strains differ in ploidy classes of binucleate cells. Development of liver polyploidization does not depend on life span of the specific strain.

Aging↗
PubMed1995

Genome reorganization from polyteny to polyploidy in the nurse cells found in onion fly (Delia antiqua) and cabbage root fly (Delia radicum) ovaries (Diptera, Anthomyiidae).

The material required to ensure successful embryogenesis in the onion fly (Delia antiqua) and the cabbage root fly (Delia radicum) (Diptera, Anthomyiidae) is supplied by 15 nurse cells, while the oocyte chromosomes enter a quiescent stage during prophase I of meiosis. This level of transcription is achieved by the polyploidization of the nurse cell DNA. Elongate polytene chromosomes form in both species, but lack the banding and conspicuous puffing commonly seen in other dipteran tissues. The polytene chromosomes contract until they finally appear as small, densely staining spheres. These fragment into large numbers of endochromosomes that are much smaller than their mitotic counterparts, which then despiralize, resulting in the flocculate appearance of the nurse cell nucleus. Photodensitometry revealed a gradient of DNA values between nurse cells near the oocytes and those further away. Final DNA values 1000 times the haploid level were recorded in the nurse cell nearest to the oocyte compared with 336 times the C-value in the most distal cell. At lower temperatures (< 10 degrees C), the polytene chromosomes become banded and longer. None of the onion flies kept in these conditions produced viable eggs, though there was some reproductive success among the cabbage root flies.

Animals↗
PubMed1986

Post-meiotic DNA synthesis in nocodazole-blocked nuclei during conjugation of Tetrahymena thermophila. Induction of polyploidy in the micronucleus.

The formation of single, polyploid micronuclei was induced during conjugation of Tetrahymena thermophila with Nocodazole (ND) according to Kaczanowski et al. The increase in DNA content in these nuclei was measured cytophotometrically in conjugating pairs continuously exposed to the drug. ND-treated micronuclei ('restitution nuclei') undergo two complete rounds of DNA replication and enter the third at the time of pair separation. The DNA content of these micronuclei in late pairs was in the range 16-30C (mean 20C). This amount was similar to the sum of the DNA content of all post-meiotic products during normal conjugation at about the same stage. Thus the increase in DNA content in 'restitution' nuclei reflects some intrinsic ability of nuclei in pairing cells to replicate DNA independently of nuclear division.

Animals↗
PubMed2005

Molecular phylogeny of the Southeast Asian freshwater fish family Botiidae (Teleostei: Cobitoidea) and the origin of polyploidy in their evolution.

The freshwater fish family Botiidae is represented by seven genera on the Indian subcontinent and in East and Southeast Asia and includes diploid as well as evolutionary tetraploid species. We present a phylogeny of Botiidae including 33 species representing all described genera using the mitochondrial cytochrome b and 12s rRNA genes to reconstruct the phylogenetic relationships among the genera and to estimate the number of polyploidisation events during their evolution. Our results show two major lineages, the subfamilies Leptobotiinae with the genera Leptobotia and Parabotia and Botiinae with the genera Botia, Chromobotia, Sinibotia, Syncrossus, and Yasuhikotakia. Our results suggest that two species that were traditionally placed into the genus Yasuhikotakia form a monophyletic lineage with the species of Sinibotia. A review of the data on the ploidy level of the included species shows all diploid species to belong to Leptobotiinae and all tetraploid species to Botiinae. A single polyploidisation event can therefore be hypothesised to have occurred in the ancestral lineage leading to the Botiinae.

Animals↗