Triploid Cells Research Articles

Stability of the “two active X” phenotype in triploid somatic cells

We examined triploid cells of XXY karyotype heterozygous for glucose 6 phosphate dehydrogenase (G6PD) electrophoretic variants with regard to the stability of their X chromosome phenotype. Clonal populations of cells derived from these human fibroblasts maintained a precise 1:2:1 ratio of A:heteropolymer:B isozymes throughout their life span, indicating stability of the two active X chromosomes in these cells. To determine the influence of the autosomal complement on X chromosome expression, we attempted to perturb the relationship. Fusion of these triploid cells with human diploid fibroblasts carrying a novel G6PD variant (B') resulted in heterokaryons expressing a novel heteropolymer, presumably indicating that all three parental X chromosomes were active. However, no derepression of the inactive X chromosome was observed. Analysis of interspecific hybrids derived from triploid cells and mouse fibroblasts confirmed that activity of parental X chromosomes is maintained. Some human mouse hybrid clones, however, expressed only a single human G6PD isozyme, probably attributable to segregation of the pertinent X chromosome, but elimination of a relevant autosome cannot be excluded. The triploid cells transformed by SV40 showed alterations in LDH pattern and an approximately 10–20% decrease in chromosome number, but maintained the precise G6PD phenotype of the untransformed cell. These studies provide evidence for the stability of the X chromosome phenotype in triploid cells.

Polyploid Mosaics Induced by Cytochalasin B in Landlocked Atlantic Salmon Salmo salar

Abstract Polyploid mosaicism was induced in landlocked Atlantic salmon by treatment of fertilized eggs with 10 mg/liter solution of cytochalasin B. On the basis of nuclear size in 3,025 erythrocytes and chromosome counts we judged the treated fish to be polyploid mosaics of diploid, triploid, and tetraploid cells. The dominant polyploid cell type in test fish was triploid rather than tetraploid, in contrast to previous reports of Atlantic salmon exposed to cytochalasin B. Control groups had mainly diploid cells but a few triploid cells were measured in most individuals.

Cell ploidy in molar placental disease.

Molar diseases of the placenta is associated with cystic change in the villi. The cysts may be from 5-20+ mm in diameter. This disease has been described in association with triploid and diploid cell lines and with and without an accompanying embryo or fetus. It may be followed by malignant change and invasive chorio-carcinoma. In order to investigate the association between cell ploidy, embryonic development and subsequent malignancy, a detailed study of 30 conceptuses with molar disease was made, with the accompanying maternal history and follow-up. The cell ploidy was determined by measurement of nuclei by a cytoscan light microscope connected to a computer program as has been previously described. Diploid cell lines were not found with embryonic or fetal development. Triploid cell lines were always associated with an embryo or fetus. Triploidy is not associated with hyperplastic changes in the trophoblast. These results are presented and discussed.

X-chromosome inactivation and enzymatic activities in diploid and triploid fibroblasts

Diploid and triploid rabbit embryos obtained by artificial fertilization were cultured. No Barr's body in XXY and only one Barr's body in XXX triploid fibroblasts was observed. Six enzymatic activities were also determined. Two X-chromosome-bound enzymatic activities, glucose-6-phosphate dehydrogenase and phosphoglycerate kinase, were significantly increased in triploid fibroblasts, while another X-chromosome-bound activity (hypoxanthine phosphoribosyl transferase) was not modified. Among the autosome-bound activities studied, pyruvate kinase and adenine phosphoribosyl transferase were not modified, whereas in the triploid cells the 6-phosphogluconate dehydrogenase activity was decreased. The relationship between these modifications of enzymatic activities in triploids and the X-chromosome inactivation is discussed.

CYTOGENETIC STUDIES IN NORTH AMERICAN MINNOWS (CYPRINIDAE). IV. SOMATIC POLYPLOIDY IN GILA BICOLOR

The kidney tissue of a single individual of the California minnow Gila bicolor (Girard) contained polyploid cells in about 1.7% frequency. Chromosome spreads of triploid, tetraploid, hexaploid, octaploid, and dodecaploid cells were observed and may have arisen through endoreduplication of ancestral diploid and triploid cells. The cytological mechanism producing the triploid cells is unknown. Diplochromosomes were not present. The distribution of ploidy in cells of this individual is not random. In particular, cells having undergone one round of chromosomal increase appear increasingly susceptible to additional rounds of chromosomal gain.

Callus Formation and Embryogenesis of Endosperm Tissues of Parsley Seed Cultured on Hormone‐Free Medium

AbstractEmbryogenic callus was induced by culturing endosperm tissues of germinating parsley seeds on Murashige‐Skoog's basal medium without any exogenous supply of growth substances. No deterioration of the embryogenic potential of this callus strain was observed on this medium for more than half a year through several passages. The endosperm callus consisted of approximately triploid cells, but diploid ones predominated in the embryos originated from this callus.

A contribution to the problem of the origin of the blastema cells in planarians: A karyological and ultrastructural investigation

AbstractThe basic problem in Planarian regeneration, i.e., the origin of blastema cells, has been tackled by means of a karyological investigation carried out on a triplo‐hexaploid biotype of Dugesia lugubris. The main characteristic of this biotype is that male germ cells are karyologically distinguishable from female germ cells and from the somatic cells.Sexually mature specimens were transected at a caudal level, posterior to the testes: from each transected specimen two regenerants were obtained, both of which formed a blastema. Thirty‐six hours after the transection most of the metaphase cells of the anterior regenerant blastema (a.r.b.) had 12 chromosomes. However, cells with 8 chromosomes as well as cells showing signs of chromosome elimination were also present. Three days after the transection only cells with 8 or 12 chromosomes could be detected in the a.r.b.The ultrastructural examination of the 36‐hours‐old a.r.b. revealed that some blastema cells display features which can be interpreted as indicating a process of dedifferentiation, the others being virtually undifferentiated. In the posterior regenerant blastema (p.r.b.) of sexually mature specimens only cells with 12 chromosomes were present. The same applies to both the a.r.b. and p.r.b. of sexually immature specimens and to developing embryos.These findings suggest that in the sexually mature planarians studied, the blastema is formed mainly by triploid cells. However, in those regenerants which still possess testes, immature male germ cells can also contribute to the blastema formation. The possible role played by these male germ cells in the reconstitution of the missing tissues in the biotype studied is also discussed.

Chromosomal localization of human genes governing the interferon-induced antiviral state.

Interferon sensitivity of different normal and aneusomic human cells and of different mouse-human hybrids cells has been compared. G21 trisomic cells are more sensitive than diploid cells; whereas, on the contrary, triploid cells are normal in their human interferon sensitivity. Among other aneusomic cell lines tested, E16 trisomic cells are significantly less sensitive. These data are in favor of the hypotheses that the G21 chromosome carries genetic information for structural proteins involved in the receptor system for interferon, that there is a regulatory mechanism governing the antiviral state, and that the E16 chromosome is a possible candidate for carrying information for such a depressive regulatory mechanism. None of the chromosome abnormalities studies are involved with interferon synthesis.

Human triploid cell strain. Phenotype on cellular level.

The complex investigation of the bilogical properties of the triploid cell strain derived from a spontaneous abortus was carried out. Cytomorphological, autoradiographic, cytochemical, biochemical and immunochemical investigation showed that, according to most of the investigated properties, triploid cells did not differ from normal diploid cells. The cells had normal form, were well orientated, revealed expressed fibrillar apparatus and viability in the culture during 15--17 passages. The decrease of the alkaline phosphatase level, increase of acid phosphatase, lactate and malatdehydrogenase and greater nuclei area were the essential differences from the control. The cells had normal mitotic cycle parameters and the antigenic spectrum was practically identical to the normal cells.

Triploidy and haploid-triploid mosaicism among chick embryos <i>(Gallus domesticus</i><i>)</i>

Homomorphic, chromosomally abnormal roosters were mated to normal hens. The 23 hens produced 67 embryos, including two triploids and a haploid-triploid mosaic at about 26 hours of incubation. Both of the triploid embryos were conceived within a 5-day period. The presence of a single genome of paternal origin with marker chromosomes in each triploid led to the conclusion that these embryos were derived from diploid, ZW-type ova fertilized by haploid, Z-type spermatozoa. The inheritance pattern of the mosaic embryo was clearly due to a spermatozoal origin for the haploid cell line; and one genome of the three in the triploid cell line was paternal. The sec chromosomes were Z/ZZZ, with one Z of each cell line being a translocation product of paternal derivation.

The inheritance of cell differentiation during limb regeneration in the axolotl

The objective of these experiments was to determine whether, when a differentiated vertebrate cell divides, its daughter cells inherit the parental cell-type determination. This problem was investigated in the regenerating limb of the axolotl by grafting differentiated cells carrying the triploid cell marker (3 nucleoli per nucleus rather than 2) into the limbs of diploid X-irradiated host animals. The limbs were then amputated through their grafts, allowed to regenerate, and the regenerates examined histologically to determine whether the cells that descended from the triploid graft had regained the parental cell differentiation. The following results were obtained. 1. 1. During limb regeneration, cartilage cells dedifferentiate morphologically and can then give rise by mitosis to cells that differentiate as cartilage, perichondrium, joint connective tissue, subepidermal fibroblasts, and fibroblasts in skeletal muscle. Cartilage cells do not give rise to epidermis, and probably not to myoblasts. 2. 2. The combination of cell types present in whole muscle can, after dedifferentiation, give rise by mitosis to all the mesodermally-derived tissues of the limb, including cartilage. 3. 3. Epidermis produces only more epidermis.

Polyploidization in vitro: formation of a predominantly triploid cell population in an originally diploid tissue culture of Microtus agrestis.

In a tissue culture of male Microtus agrestis, transformation of the originally predominantly diploid cells to a population with 85% triploid cells was observed. The change from diploid to triploid occurred between the 8th and 11th month of tissue culture. Two triploid cell lines could be distinguished and isolated, one with the karyotype 3n,XXY, the other with 3n,XYY. In about 1%, diploid cells with two X or two Y chromosomes were found. Halooid, tetraploid, hexaploid and octoploid mitoses also occurred in a low percentage. The DNA replication pattern of triploid cells in the S period was studied by means of pulse labeling with 3H-thymidine and by measuring the relative DNA content. The G2 period of triploid cells was found to be about 1 hr longer than that of diploid cells, but about 15 min shorter than that of tetraploid cells. The role of multipolar mitoses in the formation of triploid cells and diploid cells with two X or two Y chromosomes is discussed.

Euploid segregation through multipolar mitosis in mammalian cell cultures. Identification of triploid, haploid, and segregating diploid cells in a diploid-euploid primary culture of rhesus kidney cells.

Cultures were made of kidney cells of male Rhesus monkey and a karyological analysis of these cells was carried out at various times after plating using the chromosome banding method of Seabringht (1972), in order to study the segregation phenomena which take place in cell cultures in vitro through multipolar mitoses and to identify segregating cells. — Several segregating cells were found: haploid cells, diploid cells with two X chromosomes and triploid cells which were strictly euploid. Polyploidization-segregation cycles in the cell cultures and their mechanism and chronological sequence were analyzed. — On the basis of these results it was suggested that the genome is organized in haploid sets capable of segregating as units and of producing strictly euploid segregating daughter cells.

Letter: Temporal allelic interaction, a new kind of dominance.

Ustilago violacea has a simple bipolar heterothallic mating system, with two alleles a1 and a2 of the mating-type locus. Haploid yeast-like cells of opposite mating type conjugate on a medium free of nutrients1. Earlier reports from this laboratory using diploid, triploid and tetraploid cells showed that allele a2 is dominant in log phase cultures (heterozygous cells conjugate with cells homozygous for a1 but not cells homozygous for a2). Heterozygous cells in stationary phase cultures failed to mate even though all the stationary phase homozygous cells mated actively. Consequently, the dlominance of allele a2 is termed age-related2.

Regulation of gene function: a comparison of enzyme activity levels in relation to gene dosage in diploids and triploids of Drosophila melanogaster.

A study of gene activity in diploid and triploid Drosophila melanogaster females has been performed. Levels of enzyme activity of X-linked glucose 6-phosphate and 6-phosphogluconate dehydrogenases and autosome-linked α-glycerophosphate and NADP-dependent isocitrate dehydrogenases were measured and correlated with DNA content, in crude extracts of whole flies or thoraces. The results show that the contribution of each dose of a given gene to the level of enzyme activity is equal in diploid and triploid cells. These findings are discussed in the context of the phenomenon of dosage compensation.

Inhibition of Mitosis in Human Triploid Cells

TRIPLOIDY—the possession of three instead of two sets of chromosomes per cell-is a substantial cause of death in man. At least 1% of conceptions produce triploid zygotes, most of which are aborted by the end of the third month of pregnancy1. Only a few triploid infants are reported to have survived birth but the reason is not known. Death in utero also seems to be the fate of triploid rats, mice and rabbits2, but in amphibia3, Drosophila4 and many plants5,6, triploid individuals are not only viable but do not differ markedly from normal diploids.

Pattern of DNA segregation in multipolar anatelophases of different ploidy in euploid and aneuploid mammalian cells cultivated in vitro.

A microdensitometrical analysis of multipolar anatolophases of cuploid and aneuploid mammalian cells in vitro has been made in order to study the quantitative distribution of DNA to the poles. In the tripolar anatelophases of aneuploid Chinese hamster cells (obtained using colchicine) DNA is distributed to poles in an almost random way. In the spontaneous tripolar anatelophases of euploid cells of Rhesus, DNA is distributed to the poles in whole number multiples of 1c. The following distributions were observed in tetraploid cells: 14 cases of 3 : 3 : 2 and 3 cases of 4 : 2 : 2. In triploid cells, 6 cases of 2 : 2 : 2 and 1 case of 3 : 2 : 1. Thus we have deduced that each ploidy degree has a preferential distribution of sets and in contrast to the original hypothesis, random segregation of the sets is not the common occurrence. Hypotheses have been made to explain the origin of multipolar mitosis and the preferential distribution of chromatid sets to the poles. The results would confirm the existence of haploid sets of chromatids and would explain the appearance of triploid, pentaploid and hexaploid cells in tissues and cell cultures.

Corrigendum

In the article, ”Haploid chicken embryos: evidence for diploid and triploid cell populatioas“, by Stephen E. Bloom (Journal of Heredity 61:147–150. 1970) an error appeared in the text. On page 147, right column, line 18, the proportion of haploid/diploid cells was printed as (2n/n = 7); it should read (n/2n = 7).

Haploid Chicken Embryos: Evidence for Diploid and Triploid Cell Populations

Haploid Chicken Embryos: Evidence for Diploid and Triploid Cell Populations

Somatic Cell Mating and Segregation in Chimeric Frogs

Both pentaploid and haploid cells were observed in a short-term culture of bone marrow of a diploid-triploid frog chimera. Apparently, diploid and triploid marrow cells fused to form "hybrid" pentaploid cells, which subsequently gave rise by somatic reduction to haploid daughter cells. The hybrid marrow cells and their haploid segregants are presumably at a selective disadvantage, as neither type of cell has been detected in the circulating blood of chimeric frogs.