scholarly journals EVIDENCE FOR CYTOPLASMIC DNA IN ROOT CELLS OF NICOTIANA

1965 ◽  
Vol 24 (2) ◽  
pp. 267-276 ◽  
Author(s):  
Effat Badr Mourad
Keyword(s):  
Actinomycin D ◽  
Nuclear Dna ◽  
Root Cultures ◽  
Cytoplasmic Fraction ◽  
Root Tips ◽  
High Concentration ◽  
Root Cells ◽  
Cytoplasmic Component ◽  
Cytoplasmic Dna ◽  
Measurable Rate

Sterile root cultures from Nicotiana tabacum were grown with H3-thymidine added to the medium for various intervals. Incorporation of the labeled nucleoside into nuclear DNA occurred in a fraction of the nuclei which increased with time. In addition, the cytoplasm of all cells incorporated enough tritium to be readily detected by autoradiography. The tritium was not removed by hydrolysis in 1 N HCl at 60°C for 10 minutes, but was removed by digestion in a DNase solution which also removed nuclear DNA. The amount of tritium in the cytoplasm increased during the first 2 hours, but did not appear to increase significantly during the following 5 hours. If the roots were transferred to unlabeled medium after 2 hours, the label was diluted faster than expected by growth without turnover of the labeled component. If FUdR was added to the unlabeled medium, the depletion occurred faster during the first 6 hours, but later appeared to level off so that at 10 hours these cultures did not differ from those incubated without FUdR. However, the addition of an excess of unlabeled carrier had no effect on the rate of depletion of the cytoplasmic label. Actinomycin D, which inhibited the incorporation of H3-cytidine into RNA in the root tips, had no effect on the incorporation of H3-thymidine into the cytoplasmic component. However, Mitomycin C or a high concentration of deoxyadenosine inhibited the incorporation of H3-thymidine into the cytoplasmic component as well as into the nuclear DNA. It is concluded that H3-thymidine is incorporated into a cytoplasmic fraction which has the characteristics of DNA, with a measurable rate of turnover. This fraction is synthesized regardless of whether or not the nucleus is synthesizing DNA. Although the function of cytoplasmic fraction is not yet known, it does not appear to be that of supplying precursors for the synthesis of the nuclear DNA.

Effect of Niacin on Mitochondria of Allium Cepa Root Cells

1967 ◽  
Vol 25 ◽  
pp. 78-79
Author(s):  
M. Arif Hayat
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Hydrogen Transfer ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nicotinamide Adenine ◽  
Root Tips ◽  
Root Cells ◽  
Transfer Processes ◽  
Standard Procedures ◽  
A Cell ◽  
Critical Interest

Although it is recognized that niacin (pyridine-3-carboxylic acid), incorporated as the amide in nicotinamide adenine dinucleotide (NAD) or in nicotinamide adenine dinucleotide phosphate (NADP), is a cofactor in hydrogen transfer in numerous enzyme reactions in all organisms studied, virtually no information is available on the effect of this vitamin on a cell at the submicroscopic level. Since mitochondria act as sites for many hydrogen transfer processes, the possible response of mitochondria to niacin treatment is, therefore, of critical interest.Onion bulbs were placed on vials filled with double distilled water in the dark at 25°C. After two days the bulbs and newly developed root system were transferred to vials containing 0.1% niacin. Root tips were collected at ¼, ½, 1, 2, 4, and 8 hr. intervals after treatment. The tissues were fixed in glutaraldehyde-OsO4 as well as in 2% KMnO4 according to standard procedures. In both cases, the tissues were dehydrated in an acetone series and embedded in Reynolds' lead citrate for 3-10 minutes.

Cytoplasmic DNA of hepatoma tumor cells studied by3H-actinomycin D binding

1975 ◽  
Vol 31 (3) ◽  
pp. 360-361 ◽  
Author(s):  
Joanne Aczel ◽  
Hildegard E. Enesco
Keyword(s):  
Tumor Cells ◽  
Actinomycin D ◽  
Cytoplasmic Dna

scholarly journals The Endoplasmic Reticulum and the Golgi Structures in Maize Root Cells

1959 ◽  
Vol 5 (3) ◽  
pp. 501-506 ◽  
Author(s):  
W. Gordon Whaley ◽  
Hilton H. Mollenhauer ◽  
Joyce E. Kephart
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Electron Microscope ◽  
Nuclear Envelope ◽  
Epoxy Resin ◽  
Maize Root ◽  
Root Tips ◽  
Animal Cells ◽  
Root Cells ◽  
Vesicular Structure

Maize root tips were fixed in potassium permanganate, embedded in epoxy resin, sectioned to show silver interference color, and studied with the electron microscope. All the cells were seen to contain an endoplasmic reticulum and apparently independent Golgi structures. The endoplasmic reticulum is demonstrated as a membrane-bounded, vesicular structure comparable in many aspects to that of several types of animal cells. With the treatment used here the membranes appear smooth surfaced. The endoplasmic reticulum is continuous with the nuclear envelope and, by contact at least, with structures passing through the cell wall. The nuclear envelope is characterized by discontinuities, as previously reported for animal cells. The reticula of adjacent cells seem to be in contact at or through the plasmodesmata. Because of these contacts the endoplasmic reticulum of a given cell appears to be part of an intercellular system. The Golgi structures appear as stacks of platelet-vesicles which apparently may, under certain conditions, produce small vesicles around their edges. Their form changes markedly with development of the cell.

scholarly journals Actinomycin D Induces Histone γ-H2AX Foci and Complex Formation of γ-H2AX with Ku70 and Nuclear DNA Helicase II

2005 ◽  
Vol 280 (10) ◽  
pp. 9586-9594 ◽  
Author(s):  
Hannah Elisabeth Mischo ◽  
Peter Hemmerich ◽  
Frank Grosse ◽  
Suisheng Zhang
Keyword(s):  
Complex Formation ◽  
Actinomycin D ◽  
Nuclear Dna ◽  
Dna Helicase ◽  
Dna Helicase Ii

scholarly journals Cytogenetic impact of sodium chloride stress on root cells of Vigna radiata L. seedlings

2020 ◽  
Vol 45 (2) ◽  
Author(s):  
Jabeen Farheen ◽  
Simeen Mansoor
Keyword(s):  
Mitotic Division ◽  
Root Tip ◽  
Ecological Problem ◽  
Root Tips ◽  
Root Cells ◽  
Nacl Concentration ◽  
Seedling Roots ◽  
Metaphase Stage ◽  
Tip Cells ◽  
Root Tip Cells

AbstractObjectivesThe high salinization stress to seedling is the substantial ecological problem in the ongoing era. It negatively influences the growth that retard mitotic division by enhancing aberrations in nuclear chromatin. In the light of these views, the current work was designed to investigate the response of Vigna seedlings root tip cells to the presence of NaCl ions.Materials and methodsNM-92 and NM19-19 seeds were imbibed separately in distilled water for 24 h and allowed to grow into 0, 50, 150, 250, and 350 mM NaCl solution for 24 h. Excised root tips were stained, and slides were scored at 100× objective for the mitotic index (MI) and chromosomal aberrations.ResultsOur data demonstrated that as NaCl molarity increased, the MI was declined along with various chromatin abnormalities. The 150 mM of NaCl showed more lagging (69%) of chromosomes during anaphase in NM19-19. The highest stickiness at metaphase stage (68%) was found in 250 mM NaCl in variety NM19-19. However, both varieties were differed non-significantly for c-mitosis that was recorded 99% at 350 mM NaCl concentration.ConclusionsThe NaCl ions toxicity induced various cytological anomalies in seedling roots that adversely affect the growth of Vigna seedlings.

scholarly journals NUCLEAR DNA AND CYTOPLASMIC DNA FROM TISSUES OF HIGHER PLANTS

1965 ◽  
Vol 27 (3) ◽  
pp. 451-457 ◽  
Author(s):  
Yasuo Hotta ◽  
Alix Bassel ◽  
Herbert Stern
Keyword(s):  
Inorganic Phosphate ◽  
Nuclear Dna ◽  
Higher Plants ◽  
Soluble Fraction ◽  
Buoyant Density ◽  
Wheat Roots ◽  
Cytoplasmic Dna ◽  
Sucrose Medium

Young wheat roots were labeled with 32P-inorganic phosphate. Following the labeling period, roots were homogenized in a sucrose medium and fractionated into nuclei, cytoplasmic particles (including proplastids and mitochondria), and a soluble fraction containing most of the microsomes. DNA prepared from the particles had a higher buoyant density than that from the nuclei and showed a marked loss in total label if the roots were exposed to non-radioactive medium for 48 hours prior to fractionation of the cells.

Cytoplasmic DNA is structurally different from nuclear DNA

1983 ◽  
Vol 70 (5) ◽  
pp. 252-254 ◽  
Author(s):  
J. Koch ◽  
G. Vogt ◽  
W. Kissel
Keyword(s):  
Nuclear Dna ◽  
Cytoplasmic Dna

scholarly journals EFFECT OF ACTINOMYCIN D ON RNA SYNTHESIS AND ANTIBODY FORMATION IN THE ANAMNESTIC RESPONSE IN VITRO

1964 ◽  
Vol 119 (6) ◽  
pp. 881-893 ◽  
Author(s):  
J. Donald Smiley ◽  
John G. Heard ◽  
Morris Ziff
Keyword(s):  
Messenger Rna ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Lymphoid Cells ◽  
Limiting Factor ◽  
High Concentration ◽  
Antibody Synthesis ◽  
Anamnestic Response ◽  
Low Concentrations

Antibody synthesis in anamnestic lymphoid cells, measured by incorporation of leucine-C14 into specific antibody, was inhibited at moderate concentrations of actinomycin D. This was accompanied by marked inhibition of synthesis of RNA as measured by incorporation of H3-cytidine monophosphate. However, at low concentrations of actinomycin D, antibody synthesis was unaffected or even increased while RNA synthesis continued to be inhibited. The results obtained suggest that messenger RNA for antibody synthesis, either because it is relatively stable or present in excess, does not become a limiting factor until its synthesis is maximally inhibited. Puromycin, an inhibitor of amino acid coupling, abolished antibody synthesis in low concentration. 6-Mercaptopurine had no effect on the synthesis of antibody or RNA even at high concentration. The data obtained support the view that antibody synthesis follows pathways similar to those utilized for the formation of other types of proteins.

scholarly journals Chromosome Number, Ploidy Level, and Nuclear DNA Content in 23 Species of Echeveria (Crassulaceae)

Genes ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1950
Author(s):  
Guadalupe Palomino ◽  
Javier Martínez-Ramón ◽  
Verónica Cepeda-Cornejo ◽  
Miriam Ladd-Otero ◽  
Patricia Romero ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Chromosome Number ◽  
Ploidy Level ◽  
Dna Content ◽  
Chromosome Numbers ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Root Tips ◽  
Ploidy Levels ◽  
Dna Amounts

Echeveria is a polyploid genus with a wide diversity of species and morphologies. The number of species registered for Echeveria is approximately 170; many of them are native to Mexico. This genus is of special interest in cytogenetic research because it has a variety of chromosome numbers and ploidy levels. Additionally, there are no studies concerning nuclear DNA content and the extent of endopolyploidy. This work aims to investigate the cytogenetic characteristics of 23 species of Echeveria collected in 9 states of Mexico, analyzing 2n chromosome numbers, ploidy level, nuclear DNA content, and endopolyploidy levels. Chromosome numbers were obtained from root tips. DNA content was obtained from the leaf parenchyma, which was processed according to the two-step protocol with Otto solutions and propidium iodide as fluorochrome, and then analyzed by flow cytometry. From the 23 species of Echeveria analyzed, 16 species lacked previous reports of 2n chromosome numbers. The 2n chromosome numbers found and analyzed in this research for Echeveria species ranged from 24 to 270. The range of 2C nuclear DNA amounts ranged from 1.26 pg in E. catorce to 7.70 pg in E. roseiflora, while the 1C values were 616 Mbp and 753 Mbp, respectively, for the same species. However, differences in the level of endopolyploidy nuclei were found, corresponding to 4 endocycles (8C, 16C, 32C and 64C) in E. olivacea, E. catorce, E. juarezensis and E. perezcalixii. In contrast, E. longiflora presented 3 endocycles (8C, 16C and 32C) and E. roseiflora presented 2 endocycles (8C and 16C). It has been suggested that polyploidization and diploidization processes, together with the presence of endopolyploidy, allowed Echeveria species to adapt and colonize new adverse environments.

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