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PubMed1978

Co-replication of satellite DNA of Chironomus melanotus with mainband DNA during polytenization.

The DNAs of five Chironomus species, C. plumosus, C. nuditarsis, C. thummi thummi, C. melanotus, and Camptochironomus pallidivittatus, were investigated in analytical neutral isopycnic CsCl density gradients. DNA was isolated both from larval brains ("diploid-DNA") and salivary glands ("polytene-DNA"). The buoyant densities of mainband DNAs were 1.692 g/cm3, with the exception of C. melanotus whose mainband had a density of 1.693 g/cm3. The densities correspond to a calculated GC content of 33% and 34% respectively. Only in C. melanotus was the DNA clearly resolved into mainband DNA and two distinct satellite shoulders: Satellite I, with a buoyant density of 1.684 g/cm3 (25% GC, calculated) and satellite II of 1.679 g/cm3 (19% GC, calculated). The two satellites comprise 15% of the total DNA in the "diploid-DNA"' and they also occur in the "polytene-DNA", where they make up 11%. The results are discussed in the general context of under- and overreplication in polyploid and polytene cells.

Animals↗

PubMed1976

A cytogenetic study of human spontaneous abortions using banding techniques.

The karyotypes of 941 singleton and 42 twin abortuses and 4 cystic placentae were determined. 30.5% of the singletons were chromosomally abnormal; 49.8% of these were trisomic, 23.7% X-monosomics and 17.4% polyploid. 143 trisomies were identified by banding; over a third had an extra chromosome 16, more than 10% an extra 21 or 22 and about 5% an extra 2, 18 or 15. Examples of trisomy 3, 4, 8, 9, 10, 13, 14 and 20 were also encountered. Using the data from two other published studies, the prevalence of different trisomies was estimated and an attempt was made to relate the karyotype of the conceptus to its subsequent development.

Abortion, Spontaneous↗

PubMed1984

Induction of endoreduplication by hydrazine in Chinese hamster V 79 cells and reduced incidence of sister chromatid exchanges in endoreduplicated mitoses.

Hydrazine in high concentrations very effectively induces endoreduplication in Chinese hamster V79 cells. The addition of 5-bromodeoxyuridine (BrdU) for the duration of one cell cycle prior to the induction of endoreduplication produces diplochromosomes with sister chromatid differentiation (SCD) after differential chromatid staining. The fact that diplochromosomes with complete SCD are obtained shows that endoreduplication was induced in cells that were in G2-phase. The analysis of sister chromatid exchanges (SCEs) showed that hydrazine treatment rarely led to increased SCE frequencies in mitoses after endoreduplication, but that it caused a strong SCE induction in diploid second division metaphases in the same culture. Neither catalase nor cysteine had an effect on the induction of endoreduplication or the incidence of SCEs. Treatment of the cells with mitomycin C prior to addition of BrdU led to increased SCE frequencies. Compared with the normal mitoses from the same preparation, the mitoses after endoreduplication showed a significantly reduced induction of SCEs. In contrast to these findings, SCE induction was not reduced in the common tetraploid V 79 cells after colcemid-induced polyploidization.

Animals↗

PubMed1995

Expression of p53 protein related to human papillomavirus and DNA ploidy in superficial esophageal carcinoma.

We examined the p53 protein and human papilloma virus (HPV) by immunohistochemistry and DNA ploidy by cytofluorometry in paraffin-embedded esophageal carcinoma tissue specimens. Sixty-one patients with superficial esophageal carcinoma were operated on between 1983 and 1991 without any prior treatment. Immunostaining of the anti-p53 protein antibody (CM1) was positive in 32 carcinomas (52%). Patients with p53-positive tumors had a poorer outcome than those with p53-negative tumors (P < 0.05). In addition, patients with p53-positive tumors did not have any characteristic site of relapse. Only 5 of the 61 patients (8.2%) had HPV-positive tumors. One of these 5 carcinomas expressed both p53 protein and HPV. Three patients with HPV-positive tumors which had invaded the submucosal layer died of relapse. A determination of DNA ploidy revealed 30 patients with aneuploid tumors, 13 with polyploid tumors and 18 with diploid tumors. The outcome of the patients with aneuploid tumors was worse than that of the patients with diploid tumor (P < 0.05). p53 protein expression was not associated with DNA ploidy; however, the 16 patients who had both p53-positive and aneuploid tumors had a worse prognosis than patients with p53-negative and aneuploid tumors (P < 0.01). These findings suggest that p53 protein expression in conjunction with DNA ploidy may be a useful indicator in evaluating the prognosis of patients with superficial esophageal carcinoma.

Adult↗

PubMed1995

Determination of chromosome copy numbers in Saccharomyces cerevisiae strains via integrative probe and blot hybridization techniques.

Methods have been devised for analyzing chromosome copy numbers in S. cerevisiae strains that may be polyploid or aneuploid, as is apparent in the case of many industrial strains. The initial step involved transformation of a strain with an integrative "ploidy probe" transplacement fragment that enabled the copy number of the targeted chromosomal locus to be determined via genomic Southern blotting and quantitative probe hybridization. Dual probe co-hybridization to Southern genomic DNA blots was used to extend such locus copy number determinations to other loci within the same chromosome, thereby screening for internal consistency along the length of the chromosome. This approach was also used to extend the analysis to other chromosomes in the genome. The method was established and verified with euploid series laboratory strains and then used to examine chromosome copy numbers in three industrial strains. One brewing strain apparently contained three copies of the chromosomes tested, whilst another brewing and a baking strain showed evidence of aneuploidy.

Blotting, Southern↗

PubMed1981

Macronuclear chromatin organization in Paramecium primaurelia.

Chromatin organization and transcriptional activity in the macronucleus of the ciliate Paramecium primaurelia have been studied by electron microscopic examination of spread chromatin preparations. Under spreading conditions which inhibit the activity of endogenous nucleases and proteases, various morphologically distinct types of chromatin are seen: (1) Largely condensed chromatin in the form of 30-40 nm supranucleosomal globules which aggregate to form knobbly 40-60 nm fibres and unravel into 12 nm nucleosomal filaments; (2) In rapidly growing cells, extended chromatin arranged groups of 4-8 adjacent nucleofilaments, each bearing numerous and very densely packed lateral fibrils. These fibrils are 20 nm thick, have a smooth outline and extend to lengths of up to 3 micron. Such transcripts are grouped in units along the chromatin axis and are apparently organized in register in adjacent filaments; (3) In starved cells, extended nucleofilaments bearing only occasional RNP fibrils. These various morphological characteristics are discussed in terms of macronuclear transcriptional activity and the polyploid nature of macronuclei.

Animals↗

PubMed1980

Macronuclear DNA organization and transcription in Paramecium primaurelia.

Macronuclear DNA was isolated from Paramecium primaurelia, stock 168. Although the macronucleus is polyploid to the extent of 840C, in other respect the DNA appears to be simply organized, having neither satellite sequences nor substantial amounts of intermediately repetitive sequence. The sequence complexity of macronuclear DNA is quite low for a eukaryote cell, being approximately 19 times more complex than the genome of Escherichia coli. In addition, the GC content is low (25%) and the isolated DNA molecules have lengths mostly in the range 0.2-5 micrometer. In these various respects, the macronuclear DNA of Paramecium is similar to that of other ciliates. A clone of Paramecium cultured under controlled conditions contains polyadenylated RNA sequences which are homologous to 5-8% of the macronuclear DNA. Sequence complexity analysis indicates that the polyadenylated RNA contains two abundance classes of molecules, one present at low frequency and transcribed from approximately 10(4) genes, the other at 100 times greater concentration and transcribed from about 100 genes. The relevance of these results to the control of gene expression in Paramecium is discussed.

Animals↗

PubMed1979

Conservation of repeated DNA sequences in aneuploid human tumor cells.

A series of human neuroectodermal tumors, all containing more than the normal diploid DNA, and each with its own distinct chromosome mode, were studied using restriction enzyme cleavage and specific DNA sequence hybridization. Methods described were quite sensitive and quantitative and as few as 40 molecules with a given restriction site were reproducibly detected in total nuclear DNA. Analysis of several fluorescent gel bands associated with different chromosomal domains revealed no changes between any of the tumor and normal cells. Specific probe hybridization, using purified complex repeating sequences, indicated fidelity of base sequence, as well as preservation of the relative amounts of each of a number of minor related multimers in both the tumor and normal cells. Centromeric regions containing arrays of such sequences may be maintained in these tumor cells and furthermore it is possible that some of these cells are polyploid with respect to DNA sequences, rather than aneuploid as their chromosome profiles suggest.

Aneuploidy↗

PubMed1975

Independent replication of the ribosomal RNA genes in the polytrophic-meroistic ovaries of Calliphora erythrocephala, Drosophila hydei, and Sarcophaga barbata.

By filter saturation hybridizations the ribosomal (r)DNA contents of the ovaries Calliphora erythrocephala, Drosophila hydei, and Sarcophaga barbata have been measured in comparison to the rDNA percentages of their diploid brains. The measurements of the ovarian rDNA have been carried out on ovaries where the nurse cells in the distal egg chamber of the ovarioles had reached their highest ploidy level. The diploid rDNA content of each of the respective species was chosen as a 100% standard and the rDNA amounts of the ovaries were related to this 100% level. The results show that the ovaries of C. erythrocephala contain 135% rDNA whereas the rDNA contents in the ovaries of D. hydei and S. barbata are only 51% and 47%, respectively. Measurements carried out on isolated nuclei of the nurse cells and follicle cells in D. hydei show that both have a reduced rDNA content in comparison to the brains (45% and 70%, respectively). The data are discussed in relation to the problem of an rDNA amplification in the germ cells and an rDNA underreplication in polyploid nuclei.

Animals↗

PubMed1982

Spontaneous cell fusion and PCC formation in Bloom's syndrome.

Corresponding to 4,633 diploid lymphocytes 64 tetraploid or near-tetraploid (including one octoploid) metaphases were found in two sibs with Bloom's syndrome. Eight of the polyploid cells had resulted from cell fusion with half the chromosomes representing PCC. One similar fibroblast was also observed. In 13,584 untreated cells from persons without a chromosome-breakage syndrome no such cells were encountered (P = 0.0000176). This seems to be the first description of spontaneous fusion of nonmalignant cells. The extended segments in the G2 type PCC which correspond to the Q-bright, late-replicating chromosome parts are less tightly spiralized than other chromosome regions which renders the chromosomes similar to those which have incorporated BrdU late in the S period. Obviously the chromosome segments which replicate last also are the last to spiralize.

Bloom Syndrome↗

PubMed1994

Variations in ploidy among isolates of Botrytis cinerea: implications for genetic and molecular analyses.

Field isolates and laboratory strains of Botrytis cinerea, an ascomycetous fungus causing considerable economic losses, e.g., as "grey mould" of vine, were compared for differences in ploidy level by determining their DNA content per nucleus. Strain SAS56, an ascospore line used routinely for genetic analyses, is probably polyploid, since treatment with benomyl causes a significant reduction in DNA content per nucleus. This conclusion is substantiated by the increased sensitivity of the putative haploid derivatives to mutagens (UV and EMS). Molecular analyses (RAPD) of the haploidized strains indicate a very limited degree of heterozygosis of the parent strain SAS56. Analysis of field isolates of B. cinerea showed that their DNA content per nucleus varied considerably, indicating that aneuploidy/polyploidy is a widespread phenomenon in this species. This can explain both the variability and phenotypic instability of many field isolates of this fungus and the unusual difficulties faced by researchers in recovering stable recessive laboratory mutants. Since the haploid derivatives of SAS56 resemble the parent strain in their parasitic and physiological properties they should provide a good basis for classical and molecular genetic studies.

Base Sequence↗

PubMed1993

Self-diploidization in Saccharomyces cerevisiae kar2 heterokaryons.

Zygotes isolated by micromanipulation from crosses of Saccharomyces cerevisiae strains, one of which carries a kar mutation, give rise most frequently to cytoductant colonies showing the nuclear constitution of either one of the two haploid parental strains. In crosses of kar2-1 strains to wild-type, about 10% of the cytoductants of both mating types are homozygous autodiploids. There is evidence indicating that self-diploidization occurs by fusion between sibling nuclei in the heterokaryotic zygote. Here we describe this phenomenon and propose to take advantage of it for the construction of genotypically-defined diploids able to mate, and of polyploid strains, which are useful tools in genetic and cytological studies.

Crosses, Genetic↗

PubMed1989

Indirect mitotic nondisjunction in Vicia faba and Chinese hamster cells.

The hypothesis of indirect mitotic nondisjunction was tested in plant and mammalian cells. This hypothesis states that micronuclei derived from lagging chromosomes or chromatids are able to perform DNA synthesis and undergo mitotic condensation synchronously with main nuclei. Hence, as chromosomes, they can be moved to spindle poles together with the chromosomes of the main nuclei during mitosis. In that way chromosomes "lost" as micronuclei can be reincorporated in the main nuclei. In order to test this, both Vicia faba meristematic cells and cells of a Chinese hamster line (Cl-1) were treated with low doses of colchicine. Mitotic anomalies, micronuclei and cells with a polyploid or aneuploid karyotype were scored at different fixation times. A detailed analysis was performed on single chromosome misdistributions, as well as on micronuclei and cells with aneuploid karyotypes derived from single chromosome misdistributions. Indirect mitotic nondisjunction was shown to play a primary role in the origin of aneuploid karyotypes in Vicia faba, but not in Cl-1 cells.

Animals↗

PubMed1987

Does in vitro colony formation and chemosensitivity relate to DNA ploidy and S-phase fractions?

In vitro colony formation and chemosensitivity were analyzed in 65 human solid tumors and compared to proliferation parameters simultaneously obtained by DNA flow cytometry of the same tumor specimens. Colony growth in the human tumor colony assay was enhanced in aneuploid tumors (39/65) in comparison to diploid tumors (26/65, P less than 0.05). In addition, there was a relationship between % S-phase and colony growth. The existence of polyploid sublines (23/65) improved in vitro growth even in tumors with a diploid main G0/1-peak or with a low % S-phase. Metastases exhibited a higher proportion of aneuploidy and showed slightly better growth in vitro than primary tumors. Sensitivity testing in 34 of the 65 tumors showed no convincing relation between DNA parameters and the inhibition of colony formation by five standard anticancer agents with different mechanisms of action. This indicates additional factors other than the proliferative activity of the tumor to be responsible for drug sensitivity or resistance.

Antineoplastic Agents↗

PubMed1977

Rapid determination of polyploidy in human chorionic tissue sections.

Chromosomal analysis from aborted tissue has become an important diagnostic aid. However, the necessary cultures are frequently unsuccessful due to the condition of the aborted tissue. Polyploidy, in particular triploidy, in the conceptus is a common cause of early pregnancy loss and unlike aneuploidy does not appear to be associated with an increased recurrence risk. The necessity to monitor a subsequent pregnancy with amniocentesis is therefore eliminated. Therefore, in cases where a chromosomal anomaly is probable, a fast simple method of identification of a polyploid karyotype would be valuable. In this presentation, we describe a method using a scanning light microscope and histologic tissue preparations. This method can accurately determine the ploidy of the aborted material in 5 days.

Abortion, Spontaneous↗

PubMed1981

Cytokinetic behavior of Ehrlich ascites tumor after in vivo treatment with cis-diamminedichloroplatinum(II) and metallocene dichlorides.

The influence of an in vivo treatment with optimally tumor-inhibiting doses of cis-diamminedichloroplatinum(II) (DDP), titanocene dichloride (TDC), and vanadocene dichloride (VDC) on the DNA distribution pattern, determined by pulse-cytophotometry, and on the mitotic activity of EAT cells is investigated. Whereas DDP causes an immediate and long-lasting decrease of mitoses but no disturbances of the EAT cell kinetics, a marked G2 block with a maximum at 10-12 h a. t. and an irreversible and extensive mitotic depression is evoked by TDC. In the case of DDP and TDC, the tumor cells are removed several days a. t. by cells belonging to the defensive system of the host animals. In contrast, VDC induces partially synchronized waves after a transient suppression of mitoses and reversible cell accumulation in the late S and in the G2 phases. Additionally, 5-16% of the cells become polyploid after VDC treatment.

Animals↗

PubMed1985

Fungal flora of Egyptian baladi bread with special reference to the mutagenic effects of their toxic metabolites.

The fungal flora of wheat flour and baladi bread in upper Egypt were investigated. Most of the isolated fungal species belong to the genus Aspergillus. The presence of non heat resistant fungi of the both flat surfaces of baladi bread, came from contamination after baking and from improper handling at homes. Among the heat resistant fungi, A. fumigatus and A. niger, were recorded to inhabit the spongy crumb although the high temperature of baking process which reached approximately 100 degrees C in the center of the bread. The mutagenic effects of the fungal metabolites of the extract of mouldy Egypt were investigated. Most of the isolated fungal species all stages of mitotic division. The most interesting effect of these fungal metabolites were the induction of tripolar and quadripolar spindle. Multinucleate and polyploid cells were also observed under relatively high concentrations. It was noticed that at either higher concentrations or lower concentrations with long exposure, damaged cells were observed. The hazards involved through the consumption of individuals to such mouldy bread, is accumulation of possible deleterious effects from both long and short term exposure to these toxic metabolites.

Aspergillus↗

PubMed1977

Comparative cytogenetic and histologic studies on early malignant transformation in mesothelial tumors of the ovary.

Comparative cytogenetic and histologic studies on 18 mesothelial ovarian tumors revealed a normal chromosome complement in benign lesions, and the well-known cytogenetic pattern in cystadenocarcinomas. But all borderline tumors of the series evidenced an abnormal stem line and a more or less marked tendency to polyploidization. Serous papillary cystadenomas of this group showed in five out of six cases a stem line with the karyotype 47,XX+C10 (identified by Q-banding), present in both sides of bilateral lesions. It is evidenced that malignant change on the chromosomal level precedes histologically detectable features of malignancy. Histologic equivalents appeared, when the abnormal cell line was established. The initiation of malignant transformation therefore may be signalized by karyotype abnormalities before structural changes can be detected in the corresponding histologic specimens. The results discussed include the concepts of multicentric origin and clonal evolution of malignancy.

Cell Transformation, Neoplastic↗