Nuclear DNA

About: Nuclear DNA is a research topic. Over the lifetime, 3933 publications have been published within this topic receiving 185830 citations.

Nonrandom distribution of repeated DNA sequences with respect to supercoiled loops and the nuclear matrix.

Abstract: The DNA in a eukaryotic nucleus is arranged into a series of supercoiled loops that are anchored at their bases to the nuclear matrix. We have analyzed the DNA sequences that are closest to the matrix attachment points for their relative content of specific repeated sequences. Sequences were enriched (mouse satellite, human Alu family) or depleted (mouse EcoRI repeat, monkey alpha component), depending on the specific sequence and species examined. These results can be understood in terms of a nonrandom arrangement of DNA sequences with respect to nuclear DNA loops.

Leiomyosarcomas and Benign Smooth Muscle Tumors of the Stomach: Nuclear DNA Patterns Studied by Flow Cytometry

Abstract: Paraffin-embedded archival tissue samples were used for determination of DNA ploidy by flow cytometry on 117 surgically resected gastric smooth muscle tumors (44 leiomyosarcomas, 53 leiomyomas, and 20 benign leiomyoblastomas). The technique of Hedley was used for preparation of paraffin-embedded tissue into single dissociated nuclei, and the method of Vindelov was used for staining with propidium iodide. Among the 53 leiomyomas, the DNA ploidy pattern was diploid in most tumors (87%), except for 2 DNA tetraploid/polyploid and 5 DNA aneuploid samples. In comparison, the 20 benign leiomyoblastomas had more frequent abnormal DNA histograms: DNA tetraploidy/polyploidy in 5 (25%) and DNA aneuploidy in 2 (10%). The DNA histograms of the 44 leiomyosarcomas (including 4 epithelioid leiomyosarcomas) were classified as follows: 20 cases (45%) exhibited a DNA diploid pattern, 14 cases (32%) had a DNA tetraploid/polyploid pattern, and 10 cases (23%) had DNA aneuploid peaks. For the patients with leiomyosarcomas, the DNA ploidy pattern was significantly correlated with survival (P

Echinococcus granulosus strain typing in North Africa: comparison of eight nuclear and mitochondrial DNA fragments

Abstract: Recent studies of Echinococcus granulosus molecular strain typing have enabled a better understanding of the transmission cycle of cystic echinococcosis. There have been many publications in this area but there is a need for the evaluation of these tools. We have attempted to respond to this need in our study, which assessed 8 DNA fragments of 40 E. granulosus cysts from North Africa. Parasitological material was collected from 5 types of intermediate hosts, in 5 different countries. The primers chosen to amplify DNA targets were defined either in nuclear DNA, or in mitochondrial DNA. After amplification, PCR products were sequenced. The sequences obtained were aligned and comparisons were made within the group and with GenBank sequences. Whether the target was nuclear or mitochondrial, the same 2 main groups of genotypes were found. The first one, the 'sheep' strain, was found in the human, sheep and cattle samples collected in North Africa. The second one, the 'camel' strain, was found in the camel cysts and cattle and human cysts from Mauritania. These findings further confirm the congruence of the data given by the nuclear and the mitochondrial genome.

Loss of mitochondrial DNA with aging in Drosophila melanogaster.

Abstract: The buoyant densities of nuclear and mitochondrial DNA from Drosophila melanogaster lysates has been found to show no change with increasing age in both CsCl and Cs2SO4 equilibrium density gradients. Whole fly homogenates were used to demonstrate no change in nuclear DNA content during adult life. Mitochondrial DNA increased from 1.2 to 4.3% of the total DNA during the first week of adult life and then decreased during senescence to a minimum of 1.5% at 10 weeks of age which represented a 65% loss in mitochondrial DNA content with age. These data are interpreted to support the proposal that mitochondria destruction occurs during senescence.

Variable amounts of DNA related to the size of chloroplasts III. Biochemical determinations of DNA amounts per organelle

Abstract: Plastid genomes (plastomes) are part of the integrated compartmentalised genetic system of photoautotrophic eukaryotes. They are highly redundant and generally dispersed in several regions (nucleoids) within organelles. DNA quantities and number of DNA-containing regions per plastid vary and are developmentally regulated in a way not yet understood. Reliable quantitative data describing these patterns are scarce. We present a protocol to isolate fractions of pure plastids with varying average sizes from leaflets (≤1 mm) and leaves of different developmental stages continuously up to maturity (25 cm) from Beta vulgaris L. (sugar beet) to determine DNA amounts per organelle. The approach is based on plastid purification from homogenates of moderately fixed tissue by differential and isopycnic gradient centrifugations and on application of two different DNA specific colorimetric reactions after removing potentially interfering compounds. The sensitive fluorochrome DAPI (4′,6-diamidino-2-phenylindole) was used to estimate numbers and emission intensity of nucleoids per plastid. The amounts determined ranged from 0.15 to 4.9 × 10−2 pg DNA for plastids of 1→8 μm average diameter, corresponding from approximately a dozen to 330 genome equivalents per organelle and on average four to seven copies per nucleoid. The ratio of plastid/nuclear DNA changed continuously during leaf development from as little as 0.4% to about 20% in fully developed leaves. On the other hand, mesophyll cells of mature leaves differing in ploidy (di-, tri- and tetraploid) appeared to maintain a relatively constant nuclear genome/plastome ratio, equivalent to about 1,700 copies per C-value.