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PubMed2006

Nuclear DNA content of Vitis vinifera cultivars and ploidy level analyses of somatic embryo-derived plants obtained from anther culture.

Flow cytometry was employed to determine the ploidy level of Vitis vinifera L. somatic embryo-derived plants obtained from anther culture. Only one among the 41 analysed plants (2.4%) presented somaclonal variation (tetraploidy); the other plants were diploid. No significant differences (P<or=0.05) were detected between diploid and parental field plants. No haploid or aneuploid plants were observed. The nuclear DNA content of nine V. vinifera cultivars was also estimated using flow cytometry. A non-significant variation was found among the cultivars, with DNA content ranging from 1.17 pg/2C (cv. 'Tinta Barroca' and 'Viosinho') to 1.26 pg/2C (cv. 'Cabernet Sauvignon'). These results and previous studies on other Vitis species suggest that Vitis genome is stable with regard to nuclear DNA content.

Cell Nucleus↗
PubMed1981

Flow cytometry of breast carcinoma: I. Relation of DNA ploidy level to histology and estrogen receptor.

Flow cytometry studies of the DNA distribution of tumor cells from 92 human breast cancers showed measurable aneuploidy (hyperploidy) in 83 cases (92%). The DNA ploidy values were unimodal in each case, but there was a bimodal distribution for the entire series. One group of tumors had a diploid or near diploid DNA distribution and a second group had ploidy levels from triploid to tetraploid or higher. The tumors with lower DNA ploidy (at or near diploid) tended to be histologically low grade, cytologically more orderly and estrogen-binding positive; those with higher DNA ploidy were more likely to be higher grade, more anaplastic, and estrogen-binding negative.

Breast Neoplasms↗
PubMed2004

Spatial structure and genetic diversity of two tropical tree species with contrasting breeding systems and different ploidy levels.

Analyses of the spatial distribution pattern, spatial genetic structure and of genetic diversity were carried out in two tropical tree species with contrasting breeding systems and different ploidy levels using a 50-ha demographic plot in a lowland dipterocarp forest in Peninsular Malaysia. Shorea leprosula is a diploid and predominantly outcrossed species, whereas S. ovalis ssp. sericea is an autotetraploid species with apomictic mode of reproduction. Genetic diversity parameters estimated for S. leprosula using microsatellite were consistently higher than using allozyme. In comparisons with S. leprosula and other tropical tree species, S. ovalis ssp. sericea also displayed relatively high levels of genetic diversity. This might be explained by the lower pressure of genetic drift due to tetrasomic inheritance, and for autotetraploids each locus can accommodate up to four different alleles and this allows maintenance of more alleles at individual loci. The observed high levels of genetic diversity in S. ovalis ssp. sericea can also be due to a random retention of more heterogeneous individuals in the past, and the apomictic mode of reproduction might be an evolutionary strategy, which allows the species to maintain high levels of genetic diversity. The spatial distribution pattern analyses of both species showed significant levels of aggregation at small and medium but random distribution at the big diameter-class. The decrease in magnitude of spatial aggregation from small- to large-diameter classes might be due to compensatory mortality during recruitment and survival under competitive thinning process. Spatial genetic structure analyses for both species revealed significant spatial genetic structure for short distances in all the three diameter-classes. The magnitude of spatial genetic structure in both species was observed to be decreasing from smaller- to larger-diameter classes. The high spatial genetic structuring observed in S. ovalis ssp. sericea at the small-diameter class is due primarily to limited seed dispersal and apomictic mode of reproduction. The similar observation in S. leprosula, however, can be explained by limited seed and pollen dispersal, which supports further the fact that the species is pollinated by weak fliers, mainly of Thrips and Megalurothrips in the lowland dipterocarp forest.

Age Factors↗
PubMed1984

Prognostic impact of ploidy level in carcinoma of the cervix.

The single cell DNA content was analyzed by use of flow cytometry in cervical carcinoma. The study included 171 patients, Stages Ib-III. The ploidy level was calculated as a DNA index by comparison with diploid lymphocytes. Accordingly, the tumors were divided into two groups with DNA index below and above 1.5. This division proved to be important to the recurrence frequency. In all stages investigated, a statistically significant higher recurrence frequency was found in the group with DNA index above 1.5. The same relation applied concerning the survival. It is concluded that the DNA distribution is an important prognostic factor in cervical carcinoma.

Brachytherapy↗
PubMed1996

Lectin histochemistry, ploidy level and proliferation indices in meningioma subtypes.

The glycohistochemical expression of binding sites for eight lectins is characterized in a series of 15 meningothelial, 10 fibroblastic and 15 transitional meningiomas. The correlation between lectin staining and either the proliferation index or ploidy level has also been investigated. The data show that the cytochemical binding of some lectins is of value in distinguishing between the different meningioma subgroups. For example, fibroblastic meningiomas express significantly higher amounts of wheat germ agglutinin (WGA) and Ulex europaeus agglutinin (UEA-I) than the meningothelial sub-type. Diploid tumours express a higher glycine maximus (SBA), Arachis hypogaea (PNA) and Phaseolus vulgaris leukoagglutinin (PHA-L) binding than aneuploid tumours. These differences are probably due to the modification of post-transcriptional glycosylation events linked to tumour ageing. The data also reveal that the increased binding of PHA-L is inversely correlated with the proliferation indices of the tumours.

Histocytochemistry↗
PubMed2002

Ploidy levels and the number of nuclei in cardiomyocytes of the lamprey and fish.

It is well known that polyploidization of cardiomyocytes (CMC) is an essential component of heart growth in the warm-blooded vertebrates. Using the Feulgen cytophotometry of alkali-dissociated cells, we determined the ploidy in CMC of the lower vertebrates: lamprey Lampetra fluviatilis (Cyclostomata), skate Bathyraja maculata (Chondrostei), sterlet Acipenser ruthenus, and Russian sturgeon Acipenser güldenstädti (Ganoids), as well as paradise fish Macropodus opercularis, Amur sleeper Perccottus glehni, and Atlantic salmon Salmo solar (Teleostei). The data obtained have demonstrated a wide variety in CMC ploidy of both cyclostomata and fishes. About 85% of the lamprey CMC contain 2 or more (up to 17) nuclei per cell; with 90 and 10% of the nuclei being, respectively, diploid and tetraploid. Hearts of the skate and sturgeons contain mononucleated diploid CMC. In the perch-like fishes, mononucleated diploid and mononucleated tetraploid CMC make, respectively, 95 and 5%. The salmon heart contains near 50% of mononucleated diploid CMC, 13% of mononucleated tetra- and octaploid CMC, the rest CMC being multinucleated (up to 6 nuclei per cell). In all the examined species, the increased nuclear ploidy is accompanied with a significant increase in the nuclear volume. The number of nucleoli per nucleus does not correlate with the nuclear ploidy level. Evolutionary aspects of CMC polyploidy in chordates are discussed.

Animals↗
PubMed1981

A flow cytometry study of the cell cycle and of ploidy levels in Physarum polycephalum myxamoebae and plasmodia.

The cell cycle of Physarum polycephalum myxamoebae, as well as haploid and diploid and plasmodia, was analysed using laser microfluorometry. The data obtained indicate that the cell cycle of all strains examined are similar. The DNA profiles also indicate that a haploid ploidy level is still uncertain and show conclusively that spontaneous chromosome loss is a parameter of concern in research involving these organisms.

Autoradiography↗
PubMed1980

Investigations on ploidy levels of haploid and diploid callus and cell suspension cultures of Datura innoxia Mill.

Using haploid and diploid Datura innoxia Mill, callus cultures and cell suspensions it was shown that meristematic material usually attains the lowest possible C-value of a given ploidy level. Parenchyma material of callus cultures, however, indicates a broad scattering of C-values up to 16 C, which is paralleled by C-value distribution of the free cell fraction in actively dividing cell suspensions. In these suspensions, cell division activity seems to be restricted to small meristem-like clusters.

Cell Cycle↗
PubMed1987

[Ploidy level and alpha-fetoprotein production in spontaneous murine hematomas in relation to the degree of histological differentiation].

Comparative morphological, cytospectrophotometric and immunochemical studies were carried out on 26 hepatocarcinomas of various malignancy excised from 21 F1 (CBA X C57B16) mice. It has been shown that in morphologically similar hepatomas the ploidy level and alpha-fetoprotein production intensity may vary markedly. Highly differentiated carcinomas usually of smaller sizes and homogeneous morphology have the modal class nuclei with tetraploid (6 cases) or octaploid (3 cases) DNA content. In moderately- and low-differentiated carcinomas the diploid class of nuclei significantly increased (in 4 out of 6 tumours). Large tumours morphologically heterogeneous according to the differentiation level had polymodal DNA distributions with predominating tetraploid nuclei (II cases).

Animals↗
PubMedDate not supplied

DNA content and ploidy level of bovine placentomal trophoblast giant cells.

Cytophotometric measurement of the DNA content of Feulgen-stained nuclei in touch preparations of bovine placentomes (n =5) revealed that 8C nuclei occurred in all, 16C nuclei in two, and 32C nuclei in one specimen. The determination of ploidy level by in situ hybridization with a Y-chromosome specific DNA probe showed that the majority of the fetal nuclei in touch preparations of placentomes from male fetuses (n =5) are tetraploid. Generally two tetraploid nuclei lie close together. These findings indicate that polyploidization is a normal feature in the development of the mostly binucleate trophoblast giant cells (TGCs). A new model for the development of these cells is proposed: a primary acytokinetic mitosis leads to a binucleate cell with two diploid nuclei. This cell enters a second acytokinetic mitosis during which the chromosomes of both nuclei form a common metaphase plate. The resulting cell with two tetraploid nuclei undergoes an additional S-phase but does not enter a renewed mitosis. The functional significance of this genome multiplication may be an increased synthetic capacity of bovine TGCs, caused by an increased number of gene copies available for transcription. Since genome multiplication is a property of invasive trophoblast cells of different species, it may be advantageous for trophoblast invasion.

Animals↗
PubMed2004

A simple method for the calculation of microsatellite genotype distances irrespective of ploidy level.

Abstract Microsatellites are powerful molecular markers, used commonly to estimate intraspecific genetic distances. With the exception of band sharing similarity index, available distance measures were developed specifically for diploid organisms and are unsuited for comparisons of polyploids. Here, we present a simple method for calculation of microsatellite genotype distances, which takes into account mutation processes and permits comparison of individuals with different ploidy levels. This method should provide a valuable tool for intraspecific analyses of polyploid organisms, which are widespread among plants and some animal taxa. An illustration is given using data from the planarian flatworm Schmidtea polychroa (Platyhelminthes).

Animals↗
PubMed2002

Ploidy levels among species in the 'Oxalis tuberosa alliance' as inferred by flow cytometry.

The 'Oxalis tuberosa alliance' is a group of Andean Oxalis species allied to the Andean tuber crop O. tuberosa Molina (Oxalidaceae), commonly known as 'oca'. As part of a larger project studying the origins of polyploidy and domestication of cultivated oca, flow cytometry was used to survey DNA ploidy levels among Bolivian and Peruvian accessions of alliance members. In addition, this study provided a first assessment of C-values in the alliance by estimating nuclear DNA contents of these accessions using chicken erythrocytes as internal standard. Ten Bolivian accessions of cultivated O. tuberosa were confirmed to be octoploid, with a mean nuclear DNA content of approx. 3.6 pg/2C. Two Peruvian wild Oxalis species, O. phaeotricha and O. picchensis, were inferred to be tetraploid (both with approx. 1.67 pg/2C), the latter being one of the putative progenitors of O. tuberosa identified by chloroplast-expressed glutamine synthetase data in prior work. The remaining accessions (from 78 populations provisionally identified as 35 species) were DNA diploid, with nuclear DNA contents varying from 0.79 to 1.34 pg/2C.

Bolivia↗
PubMed2005

Heterozygous indels as useful tools in the reconstruction of DNA sequences and in the assessment of ploidy level and genomic constitution of hybrid organisms.

In this paper we describe a simple approach using double peaks in chromatograms generated as artefacts in the vicinity of heterozygous indels, to identify the specific sequences present in individual strands of a given DNA fragment. This method is useful to assign bases in individuals that are heterozygous at multiple sites. In addition, the relative sizes of the double peaks help to determine the ploidy level and the relative contribution of the parental genomes in hybrids. Our interpretation was confirmed with the analysis of artificial mixtures of DNA of two different species. Results were robust with varying PCR and sequencing conditions. The applicability of this method was demonstrated in hybrids of the Squalius alburnoides complex and in heterozygotes of Chondrostoma oligolepis. Far from being limited to these fish models and the gene where it was tested (beta-actin), this sequence reconstruction methodology is expected to have a broader application.

Animals↗
PubMed2004

An efficient mannose selection protocol for tomato that has no adverse effect on the ploidy level of transgenic plants.

A protocol for Agrobacterium-mediated transformation with mannose selection was developed for cotyledon petiole, hypocotyl and leaf explants of tomato (Lycopersicon esculentum L. Mill). More than 400 transgenic plants from three tomato varieties were selected with 1% mannose in combination with 0.1-0.5% glucose. Average transformation frequencies ranged from 2.0 to 15.5% depending on the construct, genotype and type of tissue used for transformation. The highest transformation rate was obtained for hypocotyl explants from tomato variety SG048. The ploidy levels of 264 independent transgenic events and 233 non-transgenic plants regenerated from tissue culture were assessed by flow cytometry. The incidence of polyploids within the total population of transgenic plants varied from 10 to 78% and was not significantly different from the non-transgenic population. The greatest variation in the proportion of polyploids was observed in plants derived from different explant types, both in transgenic and non-transgenic regenerants, across three studied genotypes. Transgenic and non-transgenic plants regenerated from leaves included the highest number of normal diploid plants (82-100%), followed by cotyledon petiole-derived plants (63-78%). Transgenic plants produced from hypocotyls contained 22-58% diploids depending on the genotype used in transformation. Results described in this study demonstrate that, although transformation frequencies for leaf tissue are still lower under current protocols, the high percentage of diploids obtained make leaf tissue an attractive transformation target.

Agrobacterium tumefaciens↗
PubMedDate not supplied

Sex steroid hormones and receptors in relation to S-phase fraction and ploidy level in endometrial carcinoma.

Although endogenous hormones exert an effect on the proliferation of endometria adenocarcinoma, there also seems to be an autonomous proliferation of the malignant cells. Simultaneous measurement of endocrine and cell proliferation related variables in endometrial adenocarcinoma specimens are expected to increase the understanding of factors responsible for progression or regression of this form of cancer. Sixty patients with endometrial adenocarcinoma were examined. The following parameters were analysed: endogenous plasma concentration of oestradiol, oestrone, progesterone, androstenedione and testosterone; S-phase fraction (SPF) and ploidy level, by flow cytometry; oestrogen and progesterone receptors, by immunohistochemistry. The oestrogen receptor positive tumours had a lower S-phase fraction that receptor negative tumours (p < 0.05), but SPF was still under the mean for the whole group. ER positive tumours were all diploid, while progesterone receptors were found also in aneuploid tumours. The presence of PR did not relate to lower SPF, but in an earlier study increased progesterone concentration was found to relate to lower SPF, and the antiproliferative effect of progesterone was also seen in more malignant tumours.

Adenocarcinoma↗
PubMed2003

Variation in DNA-ploidy Levels of Reynoutria Taxa in the Czech Republic.

The genus Reynoutria is represented by four taxa in the Czech Republic: Reynoutria japonica var. japonica, R. japonica var. compacta, R. sachalinensis and R. xbohemica. By using flow cytometry, cytological variability within the genus is described based on 257 Reynoutria samples. The varieties of R. japonica are cytologically uniform, var. japonica is exclusively octoploid (2n = 8x = 88) and var. compacta occurs only as a tetraploid (2n = 4x = 44), but R. sachalinensis and R. xbohemica exhibit some variation in chromosome numbers. Reynoutria sachalinensis is predominantly tetraploid (2n = 4 x = 44), but also occurs occasionally as hexaploid and octoploid cytotypes. The most common ploidy level in R. xbohemica is hexaploid (2n = 6x = 66), but tetraploid and octoploid clones were also found. The four taxa occurring in the Czech Republic are described briefly and the possible origins of the cytotypes discussed.

Chromosomes, Plant↗
PubMed2004

Genome analysis at different ploidy levels allows cloning of the powdery mildew resistance gene Pm3b from hexaploid wheat.

In wheat, race-specific resistance to the fungal pathogen powdery mildew (Blumeria graminis f. sp. tritici) is controlled by the Pm genes. There are 10 alleles conferring resistance at the Pm3 locus (Pm3a to Pm3j) on chromosome 1AS of hexaploid bread wheat (Triticum aestivum L.). The genome of hexaploid wheat has a size of 1.6 x 1010 bp and contains more than 80% of repetitive sequences, making positional cloning difficult. Here, we demonstrate that the combined analysis of genomes from wheat species with different ploidy levels can be exploited for positional cloning in bread wheat. We have mapped the Pm3b gene in hexaploid wheat to a genetic interval of 0.97 centimorgan (cM). The diploid T. monococcum and the tetraploid T. turgidum ssp. durum provided models for the A genome of hexaploid wheat and allowed to establish a physical contig spanning the Pm3 locus. Although the haplotypes at the Pm3 locus differed markedly between the three species, a large resistance gene-like family specific to wheat group 1 chromosomes was consistently found at the Pm3 locus. A candidate gene for Pm3b was identified using partial sequence conservation between resistant line Chul and T. monococcum cv. DV92. A susceptible Pm3b mutant, carrying a single-base pair deletion in the coding region of the candidate gene was isolated. When tested in a single cell transformation assay, the Pm3b candidate gene conferred race-specific resistance to powdery mildew. These results demonstrate that the candidate gene, a member of the coiled-coil nucleotide binding site leucine-rich repeat (NBS-LRR) type of disease resistance genes, is the Pm3b gene.

Alleles↗
PubMed2002

Nuclear DNA endoreduplication during petal development in cabbage: relationship between ploidy levels and cell size.

The development of cabbage petals comprises two distinct phases: a cell division phase and a consecutive phase of cell expansion until the onset of opening. In this study, cytological changes characterizing the two phases of petal development were analysed. First, the mitotic activity and the surface area of epidermal cells during petal development were investigated. The DNA content of isolated nuclei from the different stages of petal tissues was determined by flow cytometric analysis. The results show that cell differentiation, leading to expanded cells, is characterized by endoreduplication. In the proximal part of the petal, after cell division arrest, differentiation frequently involves endoreduplication and cell enlargement. By contrast, normal diploid nuclei remained in the distal part of the lamina in the mature petal. It is suggested that the developmental programmes of the cabbage petal may be a trigger for the initiation of endoreduplication. Correlation between ploidy levels and cell size is also discussed.

Brassica↗