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PubMed1969

Evidence for control of the rate of nuclear DNA synthesis by the nuclear membrane in eukaryotic cells.

Rates of DNA synthesis in root tip cells of diploid and autotetraploid snapdragon (Antirrhinum majus) seedlings and in diploid and tetraploid (mononucleate and bidiploid-nucleate) regenerating mouse-liver cells have been studied. The increase in this rate in the tetraploid cells is closely correlated with the increase in nuclear surface area, but not with the nuclear volume; this suggests a possible control of the rate of DNA synthesis by the nuclear membrane.

Animals↗

PubMed1980

Melting fine structure of filamentous fungus nuclear DNA.

Melting fine structure of the nuclear DNA isolated from the filamentous fungus Fusarium graminearum Schwabe is presented. Optical melting profiles of nuclear DNA were analyzed by using a combination of curve fitting and derivative techniques. The "melting components" were obtained from the derivative curve by a simple decomposition technique. Differential optical melting curves of unsheared nuclear DNA indicate the presence of 15 "melting components" in filamentous fungus nuclear genome. It should be emphasized that the "melting components" observed here are different from the "thermalites" which can be observed in bacteriophage DNA. The "melting components" reported here represent the separately melting of large "blocks" of fungus nuclear DNA.

Base Composition↗

PubMed2003

Nuclear DNA amounts in Macaronesian angiosperms.

Nuclear DNA contents for 104 Macaronesian angiosperms, with particular attention on Canary Islands endemics, were analysed using propidium iodide flow cytometry. Prime estimates for more than one-sixth of the whole Canarian endemic flora (including representatives of 11 endemic genera) were obtained. The resulting 1C DNA values ranged from 0.19 to 7.21 pg for Descurainia bourgeauana and Argyranthemum frutescens, respectively (about 38-fold difference). The majority of species, however, possessed (very) small genomes, with C-values <1.6 pg. The tendency towards small nuclear DNA contents and genome sizes was confirmed by comparing average values for Macaronesian and non-Macaronesian representatives of individual families, genera and major phylogenetic lineages. Our data support the hypothesis that the insular selection pressures in Macaronesia favour small C-values and genome sizes. Both positive and negative correlations between infrageneric nuclear DNA amount variation and environmental conditions on Tenerife were also found in several genera.

Atlantic Islands↗

PubMed1984

Enzymatic activation and binding of adriamycin to nuclear DNA.

Rat liver microsomal activation of the anthracycline antitumor drug, Adriamycin, in the presence of reduced pyridine nucleotide under anaerobic conditions produces reactive species that bind covalently to cellular macromolecules including DNA. Since the nuclear membrane contains enzymes capable of activating Adriamycin, we have examined activation of Adriamycin by isolated nuclei. The anaerobic incubation of Adriamycin with rat hepatic nuclei resulted in the formation of the Adriamycin semiquinone free radical. Moreover, this activation resulted in the covalent binding of Adriamycin to nuclear DNA. The binding of Adriamycin to DNA was reduced pyridine nucleotide and time dependent and was significantly decreased in the presence of reduced glutathione or ethylxanthate . Dicumerol , an inhibitor of DT-diaphorase, in contrast, had no effect on this binding. When the incubation was carried out in the presence of oxygen, no semiquinone radical was detected; however, superoxide and hydroxyl radicals were readily detected by a spin-trapping technique. Furthermore, little binding of Adriamycin to nuclear DNA was observed under aerobic conditions. These observations suggest that the nuclear activation and covalent binding of Adriamycin to DNA may be important in the biochemical actions of this drug.

Anaerobiosis↗

PubMed1981

The relationship between nuclear DNA content and centromere volume in higher plants.

The total volume of centromeres per nucleus varies widely within Triticum aestivum cv. Chinese Spring (7-fold) and between 11 higher plant species (24-fold). Such variation is closely correlated with nuclear DNA content, nuclear volume and, to a lesser extent, the total volume of nucleoli per nucleus. Centromere volume reflects minor intraspecific developmental fluctuations in nuclear size independent of variation in nuclear DNA content, but variation in nuclear DNA plays the major role in determining centromere volume. Thus, in general a given total volume of centromeric material is apparently characteristic of an approximately constant nuclear volume and mass of nuclear DNA, but largely independent of chromosome number. The range of volume of single centromeres in 4 taxa corresponds with the ranges of their single chromosome lengths or chromosome DNA contents. The centromere is, therefore, not a unit structure of constant size and mass but a chromosome segment whose highly variable volume closely reflects the volume and mass of the chromosome to which it belongs. The correlation between centromere size and chromosome size and DNA content is potentially useful for identifying single centromeres in unsquashed interphase and dividing nuclei; thereby facilitating studies of the intranuclear disposition of chromosomes. The present results for centromeres provide probably the first example to indicate that variation in the total DNA content of small segments present on each chromosome sometimes varies directly in proportion to large interspecific variation in nuclear DNA C-value. The close correlation between centromere volume, and nuclear DNA content is probably nucleotypic in origin. The functional significance of the variation in centromere volume is unknown, as is the nature of the mechanism which determines that centromere volume closely reflects nuclear and chromosome size and mass.

Cell Cycle↗

PubMed2000

Damage to DNA and activity of nuclear DNA repair and replicative enzymes following N-nitrosodiethylamine treatment to rats.

Continuous administration in the drinking water of hepatocarcinogen N-nitrosodiethylamine (NDEA) to male rats (200 mg/L) for 60 days resulted in DNA damage in the form of single strand breaks. The damage, which is measured as a shift in the sedimentation of DNA in alkaline sucrose density gradients, was found to be maximum at the fourth week of treatment, and the sedimentation pattern of DNA was found to return to near normal size by the seventh week of NDEA treatment. Simultaneously, there were perturbations in the nuclear enzymes involved in DNA replication and repair. Activities of DNA polymerase beta, DNA ligase, and topoisomerase were found to increase in as early as the first week of NDEA treatment and reached the maximum at the fourth week, and thereafter declined to normal level by the eighth week of treatment. Concomitantly, the activities of DNA polymerase alpha, DNA primase, and RNA polymerase which were unaltered in the initial period of carcinogen treatment recorded a marked increase after sixth week of NDEA treatment. Results suggest that administration of NDEA inflicts DNA damage, which is manifested as increase in DNA repair enzymes in the initial period and activated DNA replicative enzymes at a later period, indicating the active proliferation of transformed cells.

Animals↗

PubMed1990

S100 protein, neurone specific enolase, and nuclear DNA content in Spitz naevus.

The differentiation between Spitz naevus and melanoma is at times difficult. The present study was undertaken to define means to positively identify such melanocytic tumours of doubtful malignancy. Immunohistochemical staining intensity for S100 protein and neurone specific enolase (NSE) was measured in sections of 35 Spitz naevi using a microcomputer image analysis system. The data were compared with results previously obtained from 19 cases of malignant melanoma and 16 benign compound naevi. Disaggregated cells from paraffin-embedded material were stained by the Feulgen technique for DNA estimation. The nuclear DNA content distributions were measured using the same image analysis system. Compared with the malignant cases, the Spitz naevi showed significantly lower staining intensity for both S100 protein (P less than 0.0001) and NSE (P less than 0.0001). When compared with the benign compound naevi, the staining intensity was significantly lower for S100 protein (P = 0.003). The nuclear DNA distribution in Spitz naevi proved to be a normal diploid pattern in 31 cases. Four cases showed a small proportion of hyperdiploid nuclei. The results show that Spitz naevi can be significantly distinguished from malignant melanoma by staining intensity for S100 protein and NSE. A normal diploid DNA content distribution appears to be typical for Spitz naevi. Spitz and benign compound naevi show dissimilar expression of S100 protein which may indicate different patterns of differentiation in these two types of lesion. The image analysis equipment used in this study is accurate, simple to use, produces results rapidly, and is economic. Therefore, it is clinically practicable.

Biomarkers, Tumor↗

PubMed1997

Genetic variation and interspecific hybridization among natural populations of zoysiagrasses detected by RFLP analyses of chloroplast and nuclear DNA.

Genetic variations among 17 accessions of zoysiagrasses collected from natural populations in Japan were investigated by RFLP analyses of chloroplast DNA (cpDNA) and nuclear DNA. These accessions were classified into five species based on morphological characteristics: Zoysia japonica, Z. matrella, Z. tenuifolia, Z. sinica, and Z. macrostachya. On the basis of eight kinds of RFLPs in cpDNAs detected across accessions, six chloroplast genome types (types A-F) were identified. Although type-A cpDNA was shared by five accessions of japonica and four accessions of matrella, derivative cpDNAs of type A, which each arose by a mutation, were identified in one accession of japonica (type B) and in two accessions of matrella (type C). One accession of japonica which showed spikelets similar to those of shapes macrostachya, contained type-F cpDNA as did sinica and macrostachya. The two accessions of tenuifolia each showed a specific cpDNA type, i.e. types D and E. Genetic relationships among the 17 accessions were investigated by the RFLP analyses of nuclear DNA with 20 genomic and gene probes. A dendrogram constructed with genetic distances calculated from the RFLP patterns indicated four major groups among them. Six accessions of japonica comprised one group, whereas the one accession of japonica possessing the type-F cpDNA was clustered with macrostachya and sinica. Four accessions of matrella with type A cpDNA constituted another group in the dendrogram, showing a closer relationship to the japonica accessions than to the other two accessions of matrella. The remaining two accessions of matrella and tenuifolia accessions were grouped together. These data indicate that zoysiagrasses distributed in Japan harbor highly genetic variations, and that interspecific hybridization has occurred in natural populations.

DNA, Chloroplast↗

PubMed1999

Nuclear DNA fragmentation in Creutzfeldt-Jakob disease: does a mere positive in situ nuclear end-labeling indicate apoptosis?

The method of in situ end-labeling of nuclear DNA fragmentation was used in the study of ten patients (two biopsies, eight autopsies) with sporadic Creutzfeldt-Jakob disease (CJD). All the patients had the typical morphological lesions including neuron loss, spongiform change and astrocytosis. Four of them also showed prion protein (PrP) deposits in the cerebral cortex, and two of them kuru-like plaques in the cerebellum. A few cells with DNA breaks were found in the two biopsy cases; one of them, suffering from a panencephalopathic form of the disease, showed positive nuclei not only in the cerebral cortex but also in the subcortical white matter. Variable numbers of positive nuclei were observed in the gray and white matter in the eight autopsy cases, in which, although the distribution of positive cells roughly correlated with the distribution of neuron loss, no clear relationship was found as regards the distribution and degree of cell labeling and the degree of neuron loss. Furthermore, large numbers of positive cells were concentrated in a particular area, whereas a few cells were seen in a neighboring equally affected area. Positive glial cells in the plexiform layer of the CA1 area of the hippocampus, and in the frontal white matter were frequently encountered. Staining of the cytoplasm in a minority of cells was interpreted as the result of nuclear DNA leakage. None of the stained cells had the typical morphology of apoptosis; most particularly, peripheral chromatin condensation and formation of apoptotic bodies were not seen in any case. PrP deposits did not result in an increase of nuclear DNA breaks either within the area or in adjacent regions. Although positive cells were also observed in autopsy cases of controls which were processed in the same way, positive labeling as a whole was higher in CJD than in age-matched controls. These results show that brain nuclear DNA is vulnerable in CJD, and suggest that increased DNA vulnerability has a role in cell death and neuron loss. Since nuclear shrinkage and positive nuclear staining with the method of in situ end-labeling of nuclear DNA fragmentation are not exclusive to apoptosis, further information is needed to categorize cell death in CJD as apoptosis. Necrosis or other forms of cell death, as well as increased DNA vulnerability to agonal changes of the individuals, and to postmortem delay in the fixation of the tissues, may account for additional positive staining in cases examined at autopsy.

Aged↗

PubMed2003

Conflicting phylogenies of Larix (Pinaceae) based on cytoplasmic and nuclear DNA.

The phylogeny of Larix species was studied using chloroplast DNA RFLPs and nuclear ITS sequences and AFLPs. The study resolved the sister relationships between the Eurasian and Asian species and the monophyletic origin of each major geographic group. It also provides strong evidence for an early splitting of American Larix from other species in the genus. The discrepancy between phylogenies based on chloroplast DNA and nuclear DNA, previously observed by Qian et al. [Can. J. For. Res. 25 (1995) 1197], is confirmed. Various explanations for the incongruence between chloroplast DNA and nuclear DNA are discussed, and a tentative reconstruction of Eurasian Larix phylogeography is proposed.

Cluster Analysis↗

PubMed1987

[Clinicopathological studies of nuclear DNA distribution in colorectal cancer].

The nuclear DNA content of paraffin-embedded materials was measured by microfluorometry in 108 colorectal (59 colon and 49 rectal) cancers and 29 metastatic liver tumors from the colorectum. The classification of the nuclear DNA distribution is as follows: Low ploidy, 10% greater than over 4C; intermediate ploidy, 10% less than or equal to over 4C and 10% greater than over 6C; high ploidy, 10% less than or equal to over 6C. In primary lesions, thirty-one (29%) were found to contain cells with high ploidy. The ploidy pattern was not related to pathological stage. However, in curatively resected cases, only 24% of patients with high ploidy survived 10 years. This 10 year-survival rate was significantly lower as compared with 80% and 88% of patients with intermediate and low ploidy, respectively (p less than 0.05). In non-curatively resected cases, no patients with high ploidy survived 2 years, although 21% and 67% of patients with intermediate and low ploidy survived, respectively. In metastatic liver lesions, eleven materials (42%) were found to contain cells with high ploidy. Prognosis of patients with high ploidy was worse than that with intermediate and low ploidy (p less than 0.05). These observations suggest that the nuclear DNA distribution in colorectal cancers may be an important prognostic factor, independent of pathological stage.

Colonic Neoplasms↗

PubMed1989

Central giant cell granulomas of the jaws. Nuclear DNA analysis using image cytometry.

Giant cell nuclear DNA, in 30 giant cell lesions of the jaws, was quantified by computer-assisted image analysis. DNA content was then used to predict clinical behavior and outcome. 4 nuclei in each of 25 giant cells (total = 100 nuclei) were randomly selected and the DNA content was quantified by the Leitz Texture-Analysis-System-Plus. DNA in nuclei of normal appearing stromal fibroblasts (n = 20) was similarly measured. The DNA index was calculated as the mean nuclear DNA content of giant cells divided by the mean DNA content of control fibroblasts. The mean DNA-index of aggressive lesions (1.09, SD = 0.12) was not significantly different from that of non-aggressive lesions (1.18, SD = 0.15) (p = 0.093). The results indicate that the nuclear DNA content of giant cells is not useful as a predictor of the clinical behavior of giant cell lesions of the jaws.

Adolescent↗

PubMed1994

Relationship of nuclear DNA content to clinicopathologic features in colorectal cancer.

Nuclear DNA content was determined in 123 colorectal adenocarcinomas by flow cytometry using multiple frozen tumor samples. Thirty-three (26.8%) carcinomas were classified as diploid and 90 as aneuploid (73.2%). Presence of DNA aneuploidy was found to be unrelated to tumor stage and grade of differentiation and to other histopathological variables such as pattern of growth, degree of peritumoral lymphocytic infiltration, and venous invasion. However, multiploid tumors (20/123, 16.3%) were more frequently noted in advanced stages of disease (Stages III and IV, P < 0.025) and more often showed unfavorable histopathological features, especially an infiltrating pattern of growth (P < 0.05), compared with diploid and single aneuploid carcinomas. Nuclear DNA content was found to be closely related to tumor site. Carcinomas of the proximal (right and transverse) colon were more frequently diploid (19/43, 44.2% versus 14/80, 17.5%--P < 0.005) and more often displayed a DNA index (DI, defined as the ratio of the DNA content of neoplastic cells to that of normal cells) < or = 1.20 (27/43, 62.8% versus 19/80, 23.7%--P < 0.001) than did tumors localized distally to the splenic flexure. Nuclear DNA content was also found to be related to tumor type. A high proportion of mucinous adenocarcinomas showed DI values < or = 1.20 (14/21, 66.7%); conversely only 32 of 102 (31.4%) non-mucinous adenocarcinomas had a DI < or = 1.20 (P < 0.01). The nuclear DNA content of mucinous adenocarcinomas seemed to be independent of tumor location.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗

PubMed1990

[Prognostic implications of the ploidy pattern of the nuclear DNA in hepatocellular carcinomas].

The nuclear DNA contents of paraffin-embedded specimens of 41 cases of a hepatocellular carcinoma have been measured by means of flow cytometry. Results have indicated that 25 cases (61%) were diploid and 16 cases (39%) were aneuploid. In the aneuploid cases, the serum AFP level was found to be higher and stage more advanced. We also found that patients with aneuploid tumors had a poorer prognosis than those with diploid tumors, this fact uncovered by means of a Cox's proportional hazard model. In conclusion, the ploidy pattern of the nuclear DNA may serve as a useful prognostic marker for a hepatocellular carcinoma.

Adolescent↗

PubMed1989

[Clinical significance of measurement of nuclear DNA content in breast cancer].

Nuclear DNA content measured by a cytofluorometric method was investigated to evaluate its clinical significance in 73 cases with breast cancer which had extended radical mastectomy. Many cases of D type (diploid type) which had a prominent peak at the 2c region (control DNA content of lymphocytes) were safe indications for modified radical mastectomy. Bone recurrence was significantly more frequent in D type than in N type (non-diploid type) which did not have a prominent peak at the 2c region. Because D type had high positive rate of hormone receptors, endocrine therapy might be effective for many cases. Local or lung recurrence was more common in cases with N type which had a significant low cumulative survival rate compared with D type and especially N type 4c-3 of which over 4c cells more than 30% had the poorest prognosis. Therefore, multidisciplinary treatment composed of extended operation, radiation and chemotherapy was necessary to improve the prognosis of breast cancer patients with N type 4c-3. It was concluded that the measurement of nuclear DNA content in breast cancer might be useful for decision of therapy suitable for each case based on malignancy grading.

Breast Neoplasms↗

PubMed1993

Mucin-producing pancreatic tumors: a study of nuclear DNA content by flow cytometry.

Nuclear DNA content in eight surgically resected mucin-producing pancreatic tumors (MPPT) consisting of two mucinous intraductal adenocarcinomas (MIDAC), two mucinous intraductal adenomas (MIDA), one mucinous cyst-adenocarcinoma (MCAC), and three mucinous cystadenomas (MCA) were measured by flow cytometry using paraffin-embedded tissue samples. The technique of Shutte was used for the preparation of paraffin-embedded tissue into single dissociated nuclei, while the method of Vindelov was used for staining the isolated nuclei with propidium iodine. Clinicopathologically, the four patients with MIDAC or MIDA were all male and had cystic lesions with a dilated pancreatic duct at the head of the pancreas, while the four patients with MCAC or MCA were all females and had cystic tumors at either the body or tail of the pancreas. All eight patients with MPPT had no metastasis to the regional lymph nodes and were all still alive without recurrence. In an analysis of nuclear DNA content, seven of eight patients had DNA diploid tumors while one patient with a MIDAC perforating the duodenum and choledochus had a DNA aneuploid tumor. Thus, these findings suggest that DNA diploid patterns in MPPT might be associated with a favorable prognosis in MPPT although some patients whose MPPT invaded the surrounding organs might have DNA aneuploid tumors.

Adenocarcinoma, Mucinous↗

PubMed1998

Mitochondrial and nuclear DNA sequence variability among populations of rainbow trout (Oncorhynchus mykiss).

Mitochondrial and nuclear DNA variability was examined to assess population genetic structure and phylogeographic relationships in rainbow trout. Single-strand conformation polymorphisms and restriction site differences within 1055 bp of the mitochondrial D-loop region and 1566 bp of nuclear DNA in six single-copy nuclear DNA regions identified 31 mitochondrial genotypes and 50 nuclear alleles. Gene trees were constructed by sequencing each variant allele or mitochondrial genotype identified. Examination of 30 populations in 10 native rainbow trout groups using analysis of molecular variance (AMOVA) indicated that 65% of mitochondrial variability and 35% of nuclear variability was explained by differences among the 10 groups. Phylogenetic patterns evident in mitochondrial and nuclear DNA were not always concordant. Differences in the evolutionary patterns detected by mitochondrial and nuclear DNA may reflect the differential impact of past introgression events on variability in the two genomes.

Alleles↗

PubMed1975

S-phase dependent forms of DNA - nuclear membrane complexes in HeLa cells.

DNA - nuclear membrane complexes were isolated from HeLa cells and examined by either zone sedimentation analysis or isopycnic centrifugation in sucrose/CsCl gradients. The data suggest that the complexes formed during the first 10 min of the S-phase remain as stable structures throughout the cell cycle. Other DNA - nuclear membrane complexes are formed at later times during replication. These later complexes appear as multiple species and the association of DNA and the nuclear membrane seems to be of a transient nature. Together, these results suggest that both the replicative origins and the replication points of the DNA are associated with the nuclear membrane. Although the complexes formed at the start of the S-phase and at later times during the S-phase appear to differ, these differences may provide them with the needed properties to serve as spatial organizers for the temporal regulation of DNA replication.

Binding Sites↗