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PubMed2000

[Evolutionary regularities of somatic polyploidy manifestation in salivary glands of gastropod molluscs. I. Subclasses Cyclobranchia and Scutibranchia].

By means of histological and cytochemical methods, including DNA cytophotometry, the salivary glands of 11 species of molluscs of two old gastropod subclasses--Cyclobranchia and Scutibranchia (limpets)--have been investigated. In spite of some anatomical differences, the glandular epithelium of investigated molluscs includes functionally similar cell types: granular cells (with glycoproteid granular inclusions), mucocytes-I (that include sulfatic acid mucopolysaccharides), mucocytes-II (that include neutral and acid polysaccharides and proteins) and also the epithelial ciliated cells. Data of experiments on starvation and synchronous feeding of molluscs testify that all described cell types are independent. According to DNA cytophotometry data, the glandular cell nuclei are diploid in the main; only small part of the nuclei, varying in different species from 0.5 to 5.0%, displayed tetraploid DNA mass. A conclusion is made that in the oldest subclasses of gastropods (Cyclobranchia and Scutibranchia) somatic polyploidy, as a factor of tissue growth in salivary glands, is actually absent.

Animals↗
PubMed2000

[Somatic polyploidy in neurons from gastropod mollusks. I. Morphological characteristics of ganglia and neurons in the CNS of the snail Succinea lauta].

A study was made of general anatomy and histological organization of the central nervous system in Succinea lauta, a gastropod pulmonate snail. Neurons grow by means of polyploidy during the postnatal succineid ontogeny. In the adult individuals diameters of perikaria of large neurons increase 2.5 to 5 times, in comparison with young individuals. As a whole, in adult snails sizes of ganglian cells vary from 3 to 380 mkm. Most of giant neurons are in parietal, abdominal and pallial ganglia. The chromatin structure has been described in neurons of young and adult snails. The endomitotic mechanism of polyploidization in the succineid ganglioneurons is proposed.

Animals↗
PubMed2001

[Evolutionary regularities of somatic polyploidy in salivary glands of the Gastropod molluscs. II. Subclass Pectinibranchia: order Anisorbranchia].

Salivary glands of 5 species of gastropod molluscs of the order Anisobranchia, the most ancient order within the subclass Pectinibranchia, have been investigated by histological and cytochemical methods, including DNA cytophotometry. Glandular cells of the following types were recognized: granular cells (with glycoproteid granular inclusions), mucocytes-I (including sulfatic acid mucopolysaccharides), mucocytes-II (including neutral and acid polysaccharides and proteins), and epithelial ciliated cells. All the described cell types are considered to be independent and their morphofunctional characteristics coincide with those of salivary gland cells of the gastropod molluscs of subclasses Cyclobranchia and Scutibranchia. It has been shown that somatic polyploidy in salivary glands in the Anisobranchia molluscs, likely as in those of other Archaeogastropoda (Cyclobranchia and Scutibranchia), is actually absent.

Animals↗
PubMed2001

[Evolutionary regularities of the appearance of polyploidy in salivary glands of gastropod mollusks. III. A subclass of Pectinibranchia: Orders Discopoda, Echinospirida, Aspidophora and Entomostoma (Mesogastropoda)].

By means of histological methods and DNA cytophotometry, a study was made of the salivary glands of 16 species of gastropod molluscs belonging to the subclass Pectinibranchia and making a group of Mesogastropoda. Four cell types of salivary glands were distinguished: granular cells (with glycoproteid granular inclusions), mucocytes-I (with sulfatic acid mucopolysaccharides), mucocytes-II (with neutral and acid polysaccharides and proteins), and also the epithelial ciliated cells and mucous duct cells. Data of experiments on starvation and synchronous feeding of molluscs have testified that all described cell types are independent. In some species differentiation on protein and mucous departments within the glandular epithelium was shown. In some marine representatives of the orders Discopoda and Aspidophora polyploid cells with the ploidy levels from 8c to 32c were revealed along with diploid cells. The ecological and phylogenetic regularities of somatic polyploidy manifestation in Mesogastropoda are discussed.

Animals↗
PubMed2002

Forced expression of the interferon regulatory factor 2 oncoprotein causes polyploidy and cell death in FDC-P1 myeloid hematopoietic progenitor cells.

The IFN regulatory factor-2 (IRF-2) oncoprotein controls the cell cycle-dependent expression of histone H4 genes during S phase and may function as a component of an E2F-independent mechanism to regulate cell growth. To investigate the role of IRF-2 in control of cell proliferation, we have constructed a stable FDC-P1 cell line (F2) in which expression of IRF-2 is doxycycline (DOX)-inducible, and a control cell line (F0). Both the F2 and F0 cell lines were synchronized in the G1 phase by isoleucine deprivation, and IRF-2 was induced by DOX on release of cells from the cell cycle block. Flow cytometric analyses indicated that forced expression of IRF-2 has limited effects on cell cycle progression before the first mitosis. However, continued cell growth in the presence of elevated IRF-2 levels results in polyploidy (>4n) or genomic disintegration (<2n) and cell death. Western blot analyses revealed that the levels of the cell cycle regulatory proteins cyclin B1 and the cyclin-dependent kinase (CDK)-inhibitory protein p27 are selectively increased. These changes occur concomitant with a significant elevation in the levels of the FAS-L protein, which is the ligand of the FAS (Apo1/CD95) receptor. We also found a subtle change in the ratio of the apoptosis-promoting Bax protein and the antiapoptotic Bcl-2 protein. Hence, IRF-2 induces a cell death response involving the Fas/FasL apoptotic pathway in FDC-P1 cells. Our data suggest that the IRF-2 oncoprotein regulates a critical cell cycle checkpoint that controls progression through G2 and mitosis in FDC-P1 hematopoietic progenitor cells.

Animals↗
PubMed1992

[Myocyte polyploidy in human cardiac pathology].

With general atherosclerosis, the ploidy of left ventricle myocytes in the hearts of patients that underwent infarction corresponds to the norm variation irrespective of the ventricle and heart weights. At heart diseases the myocyte nucleus ploidy is often much higher than the norm variability both in hypertrophied ventricles and in those with normal weight. An additional polyploidization is suggested that may occur at some natural ontogenetic periods of human development (in the childhood) during heart diseases both innate or spontaneously appearing at the particular time. Unlike, the myocardial hypertrophy in adults does not stimulate myocyte polyploidy.

Cardiomegaly↗
PubMed2006

Hybridization, polyploidy, and the evolution of sexual systems in Mercurialis (Euphorbiaceae).

Hybridization and polyploidy are widely believed to be important sources of evolutionary novelty in plant evolution. Both can lead to novel gene combinations and/or novel patterns of gene expression, which in turn provide the variation on which natural selection can act. Here, we use nuclear and plastid gene trees, in conjunction with morphological data and genome size measurements, to show that both processes have been important in shaping the evolution of the angiosperm genus Mercurialis, particularly a clade of annual lineages that shows exceptional variation in the sexual system. Our results indicate that hexaploid populations of M. annua, in which the rare sexual system androdioecy is common (the occurrence of males and hermaphrodites) is of allopolyploid origin involving hybridization between an autotetraploid lineage of M. annua and the related diploid species M. huetii. We discuss the possibility that androdioecy may have evolved as a result of hybridization between dioecious M. huetii and monoecious tetraploid M. annua, an event that brought together the genes for specialist males with those for hermaphrodites.

Biological Evolution↗
PubMed1989

[Proliferation and polyploidy of hepatocytes as indicators of liver regeneration after exposure to environmental chemical factors].

The study revealed that a comprehensive assessment of proliferation and hepatocyte polyploidy serves as an integral indicator of compensator liver regeneration and its resistance. The development of reparative regeneration is correlated with the accumulation of the significant amount of destructive cells and is regarded as an adequate reaction to the damaging effect of toxic agents. Thus it is possible to consider reparative regeneration as an indicator of hepatotoxic effect under hygienic regulation and to justify its examination under the effect of environmental hygienic factors.

Animals↗
PubMed1982

[Polyploidy in the human liver normally and in hepatitis].

DNA contents in mono- and binucleated hepatocytes have been measured using cytofluorimetry on slides of isolated human liver cells. In all, 28 patients, with the mean age of 33.7 years (ranging from 17 to 50 years), were examined, including both healthy (normal) ones and those with chronical hepatitis. The normal livers were shown to include approximately 88% of mononucleated diploid hepatocytes, and 9% of binucleated hepatocytes with diploid nuclei, whereas mononucleated tetraploid cells, binucleated cells with tetraploid nuclei and mononucleated octaploid cells made all together only a bit slightly more than 3%. The patients with hepatitis displayed markedly increased numbers of binucleated hepatocytes with diploid nuclei; some of these having more than 40% of such cells. The number of mononucleated tetraploid hepatocytes, binucleated hepatocytes with tetraploid nuclei and of mononucleated octaploid hepatocytes was seen to increase very slightly not reflecting the degree of the liver disease. It has been proposed that the normal and the reparative growth of human liver is accomplished due mainly to mitotic divisions of mononucleated diploid hepatocytes; the role of polyploidy in these processes being insignificant.

Adolescent↗
PubMed1993

Detection of aneuploidy and polyploidy in non-Hodgkin's lymphoma by computer video image analysis.

Thirty-six cases of histologically intermediate and low grade non-Hodgkin's lymphoma, classified according to the International Working Formulation, were examined using image analysis cytometry. Aneuploidy was detected in 21 cases (58%). No significant difference in either the incidence or extent of aneuploidy was seen for cases that entered remission when compared to cases that did not. Bone marrow examinations, by either aspiration or trephine biopsy, were conducted on 34 cases, with 11 showing lymphocytic infiltration. Aneuploidy was detected in 6 of the 11 cases having bone marrow involvement, while 5 cases with bone marrow infiltration were euploid. Polyploid cell distributions were detected in 3 cases, and the remaining 12 cases were diploid. The biologic significance of polyploidy among non-Hodgkin's lymphomas is not well understood, and its detection is limited to static techniques for DNA quantitation. With further investigation, awareness of its presence may reveal some insight into the clonal evolution of this neoplasm.

Adolescent↗
PubMed1977

[Aneuploidy and polyploidy in the bone marrow cells of minks of different genotypes, ages and fertility].

An analysis of aneuploidy and polyploidy in bone marrow cells of female minks of different genotype and age has shown that in young minks with unsatisfactory reproductive characteristics, and in old females, the frequency of aneuploid and polyploid cells is significantly higher as compared to that in minks having a good reproductive capacity. The increase in aneuploidy level takes place mainly in the form of hypoploidy, and an increase of the frequency of polyploid cells is accompanied by a parellel increase of the proportion of cells with a low degree of ploidy. A correlation between frequencies of appearance of aneuploid and polyploid cells in minks is observed (r = 0.69 +/- 0.27). On the basis of original and bibliographic data, a hypothesis on a genetically determined instability of karyotype in mutant minks is argumented.

Age Factors↗
PubMed1999

p21(cip-1/waf-1) deficiency causes deformed nuclear architecture, centriole overduplication, polyploidy, and relaxed microtubule damage checkpoints in human hematopoietic cells.

A recent hypothesis suggests that tumor-specific killing by radiation and chemotherapy agents is due to defects or loss of cell cycle checkpoints. An important component of some checkpoints is p53-dependent induction of p21(cip-1/waf-1). Both p53 and p21 have been shown to be required for microtubule damage checkpoints in mitosis and in G1 phase of the cell cycle and they thus help to maintain genetic stability. We present here evidence that p21(cip-1/waf-1) deficiency relaxes the G1 phase microtubule checkpoint that is activated by microtubule damage induced with nocodazole. Reduced p21(cip-1/waf-1) expression also results in gross nuclear abnormalities and centriole overduplication. p53 has already been implicated in centrosome regulation. Our findings further suggest that the p53/p21 axis is involved in a checkpoint pathway that links the centriole/centrosome cycle and microtubule organization to the DNA replication cycle and thus helps to maintain genomic integrity. The inability to efficiently upregulate p21(cip-1/waf-1) in p21(cip-1/waf-1) antisense-expressing cells in response to microtubule damage could uncouple the centrosome cycle from the DNA cycle and lead to nuclear abnormalicies and polyploidy. A centrosome duplication checkpoint could be a new target for novel chemotherapy strategies.

Cell Cycle↗
PubMed2004

Polyploidy of smooth myocytes in coronary arteries.

Study of smooth myocytes in coronary arteries of dogs with experimental coarctation of the aorta revealed increased DNA content in myocyte nuclei and increased percentage of binucleated cells. Polyploidy of vascular myocytes did not disappear after correction of the aortal defect.

Animals↗
PubMed2005

Rheumatoid arthritis and pigmented villonodular synovitis: comparative analysis of cell polyploidy, cell cycle phases and expression of macrophage and fibroblast markers in proliferating synovial cells.

AIMS: Rheumatoid arthritis (RA) and pigmented villonodular synovitis (PVNS) are aggressive diseases with progressive joint destruction. The present study aims to define cell cycle phases, polyploidy and the immunophenotype of proliferating synovial cells in both diseases. METHODS AND RESULTS: Synovial tissues from patients with proliferative-active RA, localized and diffuse PVNS were analysed by DNA flow cytometry, immunohistochemistry and double immunofluorescence with confocal laser scan microscopy. Expression of macrophage markers (CD68/CD163), fibroblast markers (h4Ph/CD55) and Ki67 antigen was examined. Synovial cells positive for either macrophage or fibroblast markers as well as double-labelled cells were found in both RA and PVNS. In RA, CD68/CD163+ synoviocytes were preferentially located in the vicinity of the synovial lining layer, while they were more randomly distributed in PVNS. Of cases with diffuse PVNS, 20% showed an aneuploid cell pattern. All samples of localized PVNS and RA were diploid. Proliferative activity was significantly higher in aneuploid PVNS. CONCLUSIONS: In spite of their histologically homogeneous appearance, proliferating synovial cells display a heterogeneous immunophenotype in both RA and PVNS, indicating functional properties of both macrophages and fibroblasts. Aneuploidy seems to be a special feature of diffuse PVNS.

Antigens, CD↗
PubMed1988

Sexual immaturity and maternal age: incidence of aneuploidy and polyploidy in first-cleavage mouse embryos.

The influence of maternal age on the incidence of aneuploidy and polyploidy was studied, using C57Bl/6J X CBA/Ca hybrid mice, including immature females, as gamete donors. The age of the females ranged from 3.5-4 wk (immature or prepubertal), to 10-12 wk (young adults), to 24-28 wk (aged females). Ovulation was induced with gonadotrophins, and the differential condensation of paternal and maternal chromosomes was used to elucidate the origin of chromosome abnormalities in first-division metaphase plates. The results indicated a high incidence of aneuploid oocytes in immature and older female mice, as compared to young adult females. Eggs of immature female mice underwent polyspermic fertilization more often than those of young adults and older females, and the production of diploid oocytes was more frequent in immature females than in the other age groups.

Age Factors↗
PubMed1975

[Progressive polyploidy in mouse liver following repeated hepatectomy].

Mouse liver regeneration after partial hepatectomy results in sharp changes of ploidy classes towards the increase of high ploidy cells and the decrease low ploidy ones. These changes retain during three months. Each following partial hepatectomy (till 3 times) intensifies the hepatocyte polyploidy with appearance of cells with 32--64 ploidy nuclei. The cell polyploidization stimulated by repeated regenerations is similar to that observed in normal postnatal liver growth.

Animals↗
PubMed2025

From bottleneck to boom: Polyploidy, genetic instability and response to artificial selection resolve the peanut paradox.

This study, the second in a three-part series, shows how peanut's polyploid origin enabled rapid diversification and enhanced domestication potential. Building on the knowledge that cultivated peanut (Arachis hypogaea) originated from a narrow hybridization between Arachis duranensis and Arachis ipa&#xeb;nsis less than 10&#x2009;000&#x2009;years ago, we are confronted with a paradox: how did such a narrow origin give rise to so much diversity-two subspecies, six botanical varieties, and thousands of landraces differing in growth habit, seed size, and pod morphology? Although several diploid Arachis species were cultivated earlier, only the allotetraploid became fully domesticated and widely adopted. The global success of peanut, despite its narrow genetic origin, suggests that polyploidization itself facilitated domestication. To test this hypothesis, we investigated how the two diploid progenitors and neoallotetraploids derived from a single hybridization and polyploidization event responded under artificial selection. In a pollinator-free greenhouse, we advanced lineages of the neoallotetraploid and its diploid parents over 6&#x2009;years, selecting for divergent seed weights. The neoallotetraploid showed a much stronger response to artificial selection than its diploid parents, while also spontaneously generating diverse phenotypic variation-including flower color, pod reticulation, and chlorophyll content-traits that distinguish A. hypogaea subspecies and landraces. These traits mirrored directional shifts in parental genome dosage caused by homoeologous exchange, supporting a causal connection with phenotype. These findings offer a compelling rationale for a domestication advantage in polyploid peanut, and provide a living demonstration of how a single ancestral tetraploid, despite an extreme genetic bottleneck, generates a phenotypic boom.

Arachis↗