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PubMed2003

Mitotic and meiotic analyses of the 'large race' of Cobitis striata, a polyploid spined loach of hybrid origin.

The large race of the Cobitis striata complex is a bisexual polyploid population. It is difficult to distinguish this polyploid loach morphologically from a sympatric diploid C. striata, the Biwa small race, indicating the close relationship between these two populations. The polyploid loach does have striata-specific satellite DNAs, but it also harbors C. biwae-related mtDNA. The large race has 2n=4x=98 chromosomes with 56 acrocentric chromosomes. Diploid C. striata has 2n=50 and C. Biwae 2n=48 chromosomes, suggesting the karyotype of polyploid striata as a combination of these two genomes. Meiotic figures showed a few quadrivalent formations besides many bivalents. Many of the quadrivalents were of metacentric chromosomes. Some were, however, made of four acrocentric or of two acro- plus two metacentric chromosomes. Chiasmata were visible in some quadrivalent association. Quadrivalent formation with chiasmata indicates the presence of homologous segments capable of crossing-over between two genomes. Thus, the general polyploid model is also applicable to this case of polyploidy.

Animals↗
PubMed2003

Genetics of the loach, Misgurnus anguillicaudatus: recent progress and perspective.

The loach Misgurnus anguillicaudatus is an interesting fish from the viewpoint of polyploidy and its related atypical reproduction. Among Japanese populations, bisexual diploid individuals are most common, but natural triploids have been recorded in some localities. Experimental crosses including induced gynogenesis and inter-specific hybridization showed that triploid loaches arose from unreduced eggs formed by sympatric diploids. Two types of unreduced eggs produced by these diploid females, bisexual and unisexual reproduction, have been identified by molecular genetic analysis. The first one required fertilization with normal sperm and produced triploids. The other one normally initiated spontaneous gynogenesis as clone, but sometimes incorporated sperm genome to generate triploid progeny. Natural tetraploids found in the specimens from commercial sources were considered as exotic fish. Progenies of tetraploid loaches such as triploids, pentaploids, and other polyploids exhibited various atypical modes of reproduction. Allozyme genetics suggested possible involvement of two or more cryptic species or races on natural polyploidization through their hybridizations and further studies using more sensitive markers are required. Recent progress in molecular techniques makes it possible to map DNA markers on the loach chromosomes. Such approaches will identify genomic synteny among cobitids. Integration of chromosome manipulation, transgenics, germ-line chimera and nuclear transplantation will open new possibilities of loach as a new experimental model, not only for basic biology, but also for aquaculture biotechnology.

Animals↗
PubMed1992

[The relationship between ploidy and morphological classification of human megakaryocytes].

The relation between polyploidy and morphological classification of human megakaryocytes was studied in bone marrow aspirates from five normal individuals. On a Wright-Giemsa stained smear, megakaryocytes were morphologically classified into four groups according to a modification of Feinendegen's classification which is considered to reflect megakaryocyte maturation. The DNA of the morphologically classified cell is measured by microcytofluorometry using DAPI (4',6-diamidino-2-phenylindole) staining after removing the Wright-Giemsa stain. Most of the normal megakaryocytes were classified into type III (mature megakaryocytes) and the maximum peak in population of the megakaryocyte ploidy was observed at 16N. In each individual, the ploidy showed a similar pattern regardless of the classification. These findings suggest that the development of ploidy depends on a factor different from the one that determined the megakaryocyte maturation of cytoplasm and the ploidy is determined at the level of a megakaryocyte precursor or the most juvenile megakaryocyte.

Adolescent↗
PubMed2005

Evidence for a monophyletic origin of triploid clones of the Amazon molly, Poecilia formosa.

Asexual reproduction in vertebrates is rare and generally considered an evolutionary dead end. Asexuality is often associated with polyploidy, and several hypotheses have been put forward to explain this relationship. So far, it remains unclear whether polyploidization in asexual organisms is a frequent or a rare event. Here we present a field study on the gynogenetic Amazon molly, Poecilia formosa. We used multilocus fingerprints and microsatellites to investigate the genetic diversity in 339 diploid and 55 triploid individuals and in 25 P. mexicana, its sexual host. Although multilocus DNA fingerprints found high clonal diversity in triploids, microsatellites revealed only two very similar clones in the triploids. Phylogenetic analysis of microsatellite data provided evidence for a monophyletic origin of the triploid clones of P. formosa. In addition, shared alleles within the triploid clones between the triploid and diploid genotypes and between asexual and sexual lineages indicate a recent origin of triploid clones in Poecilia formosa.

Animals↗
PubMed2005

[Chromosome instability in patients with different forms of cardiomyopathy and their relatives].

Comparative studies on spontaneous and induced by two agents (mytomycin C and Nickel chloride) chromosome instability have been conducted in cultured lymphocytes derived from patients with hypertrophic and dilated forms of cardiomyopathy (HCMP and DCMP) and their relatives compiling a high-risk group to develop mentioned pathologies. In patients with HCMP and DCMP, as well as in their relatives higher levels of spontaneous chromosome instability were found in comparison with the control group (comprising healthy individuals without cardiomyopathic anamnesis). Almost all the affected patients and their relatives revealed tendency to increased aneuploidy and significant elevation of polyploidy when compared with control values. It was demonstrated that nickel chloride-induced chromosome disorders registered more frequently in lymphocytes of the patients and their relatives than in cells of control subjects, but mytomycin C did not have such an affect. We assume to explain the similarity of studied parameters in patients with cardiomyopathy and their relatives as a consequence of identical rearrangements in genome functioning. The revealed analogy should be interpreted as a pre-illness condition for the individuals included in the risk-group.

Aneuploidy↗
PubMed2006

[Advances in researches on genetic markers of 2n gametes].

2n gametes are the result of meiotic mutation during micro- and mega-sporogenesis that bear the sporophytic rather than the gametophytic chromosome number. This paper reviewed the genetic markers including the morphologic, cytological, isozymes and DNA markers, which have been employed in the generation, inheritance, heterozygosity and marker-assisted breeding of 2n gametes based on the frequency of large pollen grains, cytological analyses, unexpected occurrence of polyploidy progeny and the associations between parents and progenies. Based on a better understanding of the genetic control and meiotic mutations responsible for 2n gametes formation, this could open up new prospects in the use of 2n gametes for plant breeding. It should be possible to use marker- assisted selection of superior 2n gametes for polyloid breeding.

Chromosomes, Plant↗
PubMed2005

Microsporogenesis in tetraploid accessions of Brachiaria nigropedata (Ficalho & Hiern) Stapf (Gramineae).

The genus Brachiaria (Trin.) Griseb. has achieved considerable importance to cattle production systems, as a result of the good production and adaptation of a few cultivars to poor and acid soils of the Brazilian savannas. Many of its species and accessions are polyploid and apomictic, which limits direct hybridization. To assist the breeding program, cytogenetic characterization has been undertaken on the accessions of Brachiaria collection at the Embrapa Beef Cattle Research Center. In this study, chromosome number and meiotic behavior are reported for the Brachiaria nigropedata (Ficalho & Hiern) Stapf collection. The 20 available accessions are tetraploid (2n = 4x = 36). Chromosomes paired preferentially as bivalents, but quadrivalents were found in high frequencies in some cells. Meiotic behavior was, in general, irregular, and varied among accessions. Most accessions presented more than 20% of abnormal tetrads. The most common meiotic abnormalities were those related to irregular chromosome segregation due to polyploidy, leading to micronuclei formation in the tetrad stage. A low frequency of other meiotic abnormalities such as the absence of cytokinesis, chromosome stickiness, cell fusion, anaphase bridges, and chromosome transfer among microsporocytes were also recorded in some accessions. Limitations of these accessions for use in hybridization programs are discussed.

Brachiaria↗
PubMed1991

Porokeratosis with large skin lesions. Histologic, cytologic and cytogenetic study of three cases.

Three porokeratosis patients with large skin lesion(s) are reported. The histopathology of the large lesions revealed that the epidermis 1) frequently presented slight or marked acanthosis and/or elongation of the rete ridge, and 2) contained abnormal cells, e.g. hyperchromatic, large, multinucleated, and/or irregular shaped nuclei. The DAPI-DNA microfluorometric study revealed DNA polyploidy and/or an increased population of epidermal cells with hyperdiploid and/or tetraploid DNA content. These results indicate the proliferating potential of the epidermis and the existence of a neoplastic clone or clones therein. This finding may explain the enlargement of skin lesions and possibly the development of malignancy, as sometimes occurs in large skin lesions. Furthermore, cultured skin fibroblasts from a patient's skin lesion or its surrounding skin revealed various kinds of chromosomal structural abnormalities, which may serve as a basis for the development of abnormal neoplastic clones in the porokeratotic epidermis.

Aged↗
PubMed2006

[The molecular genetic assessment of prognostic factors in carcioma of the prostate: a pilot study].

The loss of the 8p22 chromosome part and amplification of the 8q24 region (c-myc oncogene region) are the most frequent chromosomal aberrations observed in prostate carcinoma. We aimed to demonstrate the frequency of these chromosomal abnormalities and to assess how they correlate with the prognosis in patients with prostate carcinoma. From a set of 130 patients, we selected a group of 17 who died within five years after the diagnosis had been determined. Due to the lack of tumor cells in puncture biopsies, we managed to carry out in situ hybridization and assess the result objectively for 9 patients only. In seven cases, amplification of the region for c-myc oncogene was found; however, in five of them, polyploidy of chromosome 8 was manifested simultaneously. Deletion of the 8p22 chromosome part (region for the LPL gene) was found in five cases. A normal finding was detected in two cases. However, the analysis was carried out on a small number of cells gained from paraffin slices, so it was impossible to meet the requirement to examine 300 interphase cell nuclei. Therefore, we recommend to always determine whether the material taken is representative enough for this methodology and whether the tissue fixation is not inadequate or insufficient.

Aged↗
PubMed2006

[The use of hybridization in breeding of eukaryotic microorganisms].

The article deals with the genetic bases of breeding of eukaryotic microorganisms. Using the data on the Saccharomyces yeasts, application of different genetic approaches and methods to breeding is discussed, including interstrain, interlinear, and distant interspecific hybridization, as well as heterosis, polyploidy, cytoduction, and meiotic recombination.

Breeding↗
PubMed1975

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

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 dependent 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 percengate of polyploids under these conditions reached 10-20. At further increase of colcemid concentrations the proportion of polyploid cells increased. In Djungarian hamster embryonic cell cultures there were single cells with changed chromosome numbers at a concentration of the drug of 0.015-0.1 mkg/ml.

Aneuploidy↗
PubMed1990

Development of polyploidization in taxol-resistant human leukemia cells in vitro.

The effects of taxol on antitubulin immunofluorescent staining patterns, cellular DNA content, and labeling with [3H]thymidine were measured for the taxol-sensitive HL60 and taxol-resistant K562 cell lines after exposures for 0, 4, 12, and 24 h. Taxol caused a relative increase in the fraction of 4C interphase and metaphase cells in both lines although the 4C interphase accumulation was greater for the resistant K562 line. Of the cells with S-phase DNA content, taxol-treated HL60 cells were less likely to incorporate [3H]thymidine than taxol-treated K562 cells. However, a decrease in percentage of S-phase labeling for both lines relative to control cells was seen. Finally, taxol induced the development of polyploid cells (cells with DNA contents greater than that of the 4C G2-M peak) in the relatively taxol-resistant K562 cells, an effect not seen in the relatively taxol-sensitive HL60 line. After 24 h of taxol exposure 70% of all K562 cells were polyploid while only 8% of the HL60 cells were polyploid. The capacity of K562 cells to generate polyploidy in response to taxol correlated with taxol resistance by previous assay and may be a useful indicator of drug resistance.

Alkaloids↗
PubMed1990

Mitosis and polykaryon formation of Entamoeba histolytica in axenic cultures.

Axenic cultures of E. histolytica were established in Coplin jars containing glass slides. The cultures were harvested after 72 hours, fixed and stained with Giemsa and acridine orange. Sedimented parasites were used for inclusion in methacrylate for thin sections that were stained with acridine orange, and epon-araldite for ultrathin sections for electron microscope study. The Giemsa stain showed trophozoites of different sizes and variation in the shape, size and number of the nuclei. Division occurred by budding, sometimes by fission, with occasionally apparent extrusion of nuclear material into the cytoplasm. Acridine orange demonstrated DNA in the center of the nuclei and within intranuclear small vesicles. The electron microscope showed mono and multinucleated amoebae with irregular nuclear membranes, coarse material attached to the nuclear membrane, and sometimes intranuclear parallel microtubules without nuclear attachment. There were structures around the karyosome in some nuclei resembling chromosomic material of superior eukaryotes, without kinetochore, as well as intranuclear small vesicles containing sausage-shaped structures. The findings suggest that E. histolytica undergoes polyploidy evidenced by giant nuclei, followed by segregation of chromatin in smaller nuclei, by budding and production of polykaryons of different nuclear size. Multiple small intranuclear vesicles containing structures that may represent forms of rRNA thus contributing to ribosomes. Absence of cytokinesis is the cause of the production of polykaryons with an asynchronous rate of nuclear and cytoplasmic division. Polynucleation also could be related in the origin of cyst formation in amoeba, as unknown selective forces may induce amoebae the synthesis of chitin capsule.

Animals↗
PubMed1975

Cytogenetic study of the continuous RH cell line and its clones with a different susceptibility to measles virus.

A comparative karyological study was carried out on the RH continuous line of human embryo kidney cells and its 3 clones differing in their sensitivity to the cytopathic effect (CPE) of vaccine measles virus (L-16 strain). The clonal variants studied were shown to have different karyotypes and their sensitivities to be genetically determined. There was a correlation between the rate of appearance and the pattern of the CPE and the percentage of cells in which a set of 33 chromosomes and a high level of polyploidy were combined.

Cell Line↗
PubMed1989

Safety evaluation of irradiated foods in China: a condensed report.

Eight trials, with 439 human volunteers who consumed irradiated foods including rice, potatoes, mushrooms, peanuts, and Chinese sausages, as well as diets composed of multiple irradiated foods (irradiated at dosages of 0.2 to 8 kGy) that accounted for 60-66% of the entire diet, were carried out for 2-3 months according to a unified protocol. No adverse effects on body weight, blood pressure, ECG, hematology, blood enzyme activities, serum lipids or blood or urine 17-hydroxycortisol contents and no chromosomal aberration of peripheral blood lymphocytes were found. It is especially worthwhile to note that there was no change in the polyploidy after consumption of irradiated diets. On the basis of these results and a comprehensive analysis of the physical and chemical characteristics of irradiated foods, temporary hygienic standards for irradiated rice, potatoes, onions, garlic, Chinese sausages, peanuts, and mushrooms were promulgated by the Chinese Ministry of Public Health.

Adolescent↗
PubMed1989

Hereditary hepatitis in LEC rats: accumulation of abnormally high ploid nuclei.

The LEC (Long-Evans with a cinnamon-like coat color) rat is a new mutant strain with hereditary hepatitis. The rate of DNA synthesis, the relative amounts of binucleated cells, and the polyploidizations of LEC hepatocytes have been analyzed. Markedly high polyploidy, such as 32n and 64n, were detected after manifestation of hepatitis; however, no aneuploidy was detected. Bi-, tri- and tetranucleated cells whose nuclei occasionally differed in size were observed after the manifestation of hepatitis. In addition to small hepatocytes and oval cells in the periportal area of the hepatic lobule, enlarged cells with huge nuclei were also labeled with BrdU, indicating that in LEC rats suffering from hepatitis abnormal mitosis may be relevant to high polyploidization and multinucleation. Polypeptide analysis using 2D-PAGE detected the apparent lack of expression of two polypeptides, p29.5 and p30, in LEC liver cells; however, linkage analysis indicated no correlation between these peptide defects and the manifestation of hepatitis.

Aging↗