AUTORADIOGRAPHIC STUDIES ON NUCLEAR DNA AND RNA SYNTHESIS IN THE ADENOHYPOPHYSIS OF CASTRATED RATS

1970 ◽  
Vol 64 (2) ◽  
pp. 324-338 ◽  
Author(s):  
F. Städtler ◽  
E. Stöcker ◽  
G. Dhom ◽  
H. U. Tietze
Keyword(s):  
Dna Synthesis ◽  
Rna Synthesis ◽  
Nuclear Dna ◽  
Anterior Lobe ◽  
Synthesis Rate ◽  
Nuclear Area ◽  
Synthesis Time ◽  
Dna And Rna ◽  
Cell Groups ◽  
Dna And Rna Synthesis

ABSTRACT DNA and RNA synthesis was studied autoradiographically; 5 groups of cells were observed in the adenohypophysis of rats (gonadotrophs, thyrotrophs, acidophils, small and large chromophobes) 1, 2, 4 and 8 weeks following castration and the results compared with those obtained in control animals. The proliferation of cells in the anterior lobe of the hypophysis, determined by the incorporation of isotopically labelled 3H-thymidine into the nuclei of parenchymal cells, increases by 6 fold about two weeks after castration and returns to a normal level eight weeks after the operation. The number of silver grains/μm2 nuclear area =mean silver grain density (SGD) shows a doubling of the DNA-synthesis rate (= new formation/unit of time) two weeks following castration. This result agrees with a shortening of the DNA synthesis time – and very likely also of the G2 phase and the length of mitosis – to such an extent as to be characteristic for rapidly proliferating tissues. This effect on the mode of proliferation is reversible and normalized by the end of the experiment, i. e. eight weeks following castration. After the operation there is a more marked proliferation of the gonadotrophs than the chromophobic cells. RNA synthesis as measured by the incorporation of 3H=cytidine into the cell nucleus increases continuously in the nuclei of all cell groups throughout the whole period investigated. On the other hand, the average nuclear area diminishes. This dissociation of the extent of RNA synthesis and the nuclear size is discussed.

Effect of infection with R23 on DNA and RNA synthesis in Escherichia coli

1971 ◽  
Vol 17 (4) ◽  
pp. 461-466 ◽  
Author(s):  
Hiroko Watanabe ◽  
Mamoru Watanabe
Keyword(s):  
Escherichia Coli ◽  
Dna Synthesis ◽  
Rna Synthesis ◽  
Rrna Synthesis ◽  
Maximal Inhibition ◽  
Dna And Rna ◽  
Marked Inhibition ◽  
Dna And Rna Synthesis ◽  
Infected Cells

Infection of Escherichia coli by R23 results in a marked inhibition of rRNA synthesis. Both 16 S and 23 S RNA are inhibited with maximal inhibition occurring at 30 min. Inhibition of 4 S RNA is not as profound. DNA synthesis is also inhibited after R23 infection although infected cells continue to divide for about one generation (45–60 min) after infection.

scholarly journals DNA and RNA Synthesis of Circulating Atypical Lymphocytes in Infectious Mononucleosis

Blood ◽  
1965 ◽  
Vol 25 (2) ◽  
pp. 197-203 ◽  
Author(s):  
LOIS B. EPSTEIN ◽  
GEORGE BRECHER
Keyword(s):  
Dna Synthesis ◽  
Infectious Mononucleosis ◽  
Rna Synthesis ◽  
Mononuclear Cells ◽  
Early Period ◽  
Dna And Rna ◽  
Atypical Cells ◽  
Dna And Rna Synthesis ◽  
Considerable Period ◽  
Active Proliferation

Abstract The percentages of mononuclear cells synthesizing DNA and RNA in serial studies of blood from 13 patients with infectious mononucleosis were determined. Early in the disease a high percentage of atypical lymphocytes were in DNA synthesis but this percentage decreased rapidly as the disease progressed. Late in the disease many atypical lymphocytes were still present but few, if any, were synthesizing DNA. Similar results were found for RNA synthesis. Presumably active proliferation of atypical cells in the tissues is restricted to an early period of the disease, whereas release of such atypical cells may continue for a considerable period.

Oogenesis in Tenebrio molitor: Histological and autoradiographical observations on pupal and adult ovaries

Development ◽  
1973 ◽  
Vol 30 (1) ◽  
pp. 179-217
Author(s):  
Suzanne L. Ullmann
Keyword(s):  
Dna Synthesis ◽  
Rna Synthesis ◽  
Developmental Stages ◽  
Tenebrio Molitor ◽  
Follicle Cells ◽  
Nurse Cells ◽  
Dna And Rna ◽  
Primary Oocyte ◽  
Dna And Rna Synthesis ◽  
Dual Origin

(i) Nurse cells and oocytes in the telotrophic ovary of Tenebrio molitor L. (Insecta, Coleoptera-Polyphaga) are differentiated in the larval stadium. (ii) During pupation DNA synthesis occurs in the nurse cells and is probably associated with polyploidy; some of them become multinucleate. The functional significance of these events is interpreted as preparation for subsequent massive RNA synthesis. (iii) The oviducts incorporate [3H]thymidine and undergo elongation due to mitoses. This ceases at eclosion. (iv) RNA synthesis in the pupal ovary is low, but increases in the nurse cells and follicle cells just prior to eclosion. (v) In the adult ovary, once the growth phase has been initiated, a primary oocyte takes about six days to reach maturity. (vi) The nurse cells, though apparently lacking nucleoli, synthesize much stable RNA which reaches each oocyte via a trophic cord. (vii) The follicle cells undergo continuous DNA synthesis: some nuclei contain over 64 times the haploid amount of DNA. Replication is probably asynchronous within a nucleus: this may account for the phenomenon of simultaneous DNA and RNA synthesis in the follicle cells, which also lack nucleoli. (viii) Oogenesis has been divided into nine developmental stages, three of which are vitellogenic. (ix) The oocyte chromosomes are capable of RNA synthesis both when despiralized during early previtellogenesis and after karyosome formation, which occurs at stage 6. (x) The protein content of the oocyte appears to have a dual origin: at least part of the ooplasmic proteins form in situ; while yolk proteins are derived from the haemolymph. The extra-ovarian protein reaches the oocyte via spaces which develop between the follicle cells. (xi) The nucleoplasm becomes more heavily labelled with proteins than the ooplasm. With [3H]leucine, methionine and phenylalanine but not with tryptophane or arginine, there is an increased incorporation into the karyosome. It is suggested that this karyosome-associated protein may function in gene masking. (xii) The significance of these findings is discussed with reference to the literature.

scholarly journals CHARACTERIZATION OF LYMPHOCYTE TRANSFORMATION INDUCED BY ZINC IONS

1974 ◽  
Vol 61 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Nathan A. Berger ◽  
Sister Ann Marie Skinner
Keyword(s):  
Dna Synthesis ◽  
Rna Synthesis ◽  
Divalent Cations ◽  
Lymphocyte Transformation ◽  
Blast Transformation ◽  
Zinc Ions ◽  
Dna And Rna ◽  
Dna And Rna Synthesis ◽  
Human Adults ◽  
Lymphocyte Dna Synthesis

Lymphocyte cultures from all normal human adults are stimulated by zinc ions to increase DNA and RNA synthesis and undergo blast transformation. Optimal stimulation occurs at 0.1 mM Zn++. Examination of the effects of other divalent cations reveals that 0.01 mM Hg++ also stimulates lymphocyte DNA synthesis. Ca++ and Mg++ do not affect DNA synthesis in this culture system, while Mn++, Co++, Cd++, Cu++, and Ni++ at concentrations of 10-7–10-3 M are inhibitory. DNA and RNA synthesis and blast transformation begin to increase after cultures are incubated for 2–3 days with Zn++ and these processes reach a maximum rate after 6 days. The increase in Zn++-stimulated lymphocyte DNA synthesis is prevented by rendering cells incapable of DNA-dependent RNA synthesis with actinomycin D or by blocking protein synthesis with cycloheximide or puromycin. Zn++-stimulated DNA synthesis is also partially inhibited by 5'-AMP and chloramphenicol. Zn++ must be present for the entire 6-day culture period to produce maximum stimulation of DNA synthesis. In contrast to its ability to independently stimulate DNA synthesis, 0.1 mM Zn++ inhibits DNA synthesis in phytohemagglutinin-stimulated lymphocytes and L1210 lymphoblasts.

scholarly journals Lomofungin as an inhibitor of nucleic acid synthesis in Saccharomyces cerevisiae

1974 ◽  
Vol 142 (3) ◽  
pp. 457-463 ◽  
Author(s):  
Michael Cannon ◽  
Antonio Jimenez
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Synthesis ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
Growth Conditions ◽  
Dna And Rna ◽  
Dna And Rna Synthesis ◽  
Inhibition Of Dna Synthesis ◽  
Rna And Dna Synthesis ◽  
Rna And Dna

1. The antibiotic lomofungin was found to be a potent inhibitor of both DNA and RNA synthesis in Saccharomyces cerevisiae. Under selected growth conditions inhibition of DNA synthesis by the drug preceded inhibition of RNA synthesis. 2. Although in general lomofungin inhibited synthesis of ribosomal RNA and polydisperse RNA more effectively than that of low-molecular-weight RNA, under certain conditions the drug inhibited almost completely synthesis of both 4S and 5S RNA. 3. Inhibition of both RNA and DNA synthesis may be explained if RNA synthesis is required for DNA synthesis in yeast. Alternatively, lomofungin, in addition to interacting with DNA-dependent RNA polymerase, might interfere with a component(s) of the DNA-synthetic apparatus. The drug may thus prove to be of considerable value in studies of DNA synthesis in eukaryotes.

scholarly journals In Vitro DNA and RNA Synthesis in Human Bone Marrow Cells: A Study of 12 Normal Subjects and 12 Patients with Lymphoplasmocytic Disorders

Blood ◽  
1966 ◽  
Vol 27 (3) ◽  
pp. 310-318 ◽  
Author(s):  
JAKOB R. SCHMID ◽  
JOSEPH M. KIELY ◽  
W. NEWLON TAUXE ◽  
CHARLES A. OWEN
Keyword(s):  
Rna Synthesis ◽  
Plasma Cells ◽  
Bone Marrow Cells ◽  
Normal Subjects ◽  
Synthesis Rate ◽  
Dna And Rna ◽  
Dna And Rna Synthesis ◽  
Immature Cells ◽  
Marrow Cells

Abstract In 12 normal subjects, DNA and RNA synthesis by individual marrow cells was studied in vitro by autoradiography after short-term incubation with tritiated nucleosides. The DNA labeling index and RNA synthesis rate were highest in normal immature cells. The DNA index was zero in all mature cells, including small lymphocytes and plasma cells. In the most actively proliferating normal immature cells, the RNA synthesis rate was about 5 times higher than in normal plasma cells. Since both normal immature cells and plasma cells are characterized by a high content of RNA and active protein synthesis, the results of the present study suggest that a high RNA turnover may not be necessary for protein synthesis to proceed in nonproliferating, protein-producing marrow cells. In 10 patients with myeloma and in two patients with primary macroglobulinemia, the abnormal plasma cells were found to be labeled with H3thymidine in each instance. The RNA synthesis rate was about 3 times greater in plasmocytoid myeloma cells than in mature plasma cells of normal marrows, and also about 3 times greater in lymphocytoid myeloma cells than in mature lymphocytes of normal marrows. The abnormal cells in the lymphoplasmocytic disorders apparently differ from their counterparts in normal marrows not only by a higher proliferative potential, but also by a much greater rate of RNA synthesis. In actively dividing normal bone marrow cells, high values for both DNA and RNA synthesis were found. By contrast, in the neoplastic lymphoplasma cells studied, a discrepancy was noted between relatively low values of DNA synthesis and high values of RNA synthesis. Production of abnormal proteins within long-lived neoplastic plasmocytic cells may account for this finding.

The role of p53 in regulating genomic stability when DNA and RNA synthesis are inhibited

1995 ◽  
Vol 20 (10) ◽  
pp. 431-434 ◽  
Author(s):  
Olga B. Chernova ◽  
Michail V. Chernov ◽  
Munna L. Agarwal ◽  
William R. Taylor ◽  
George R. Stark
Keyword(s):  
Rna Synthesis ◽  
Genomic Stability ◽  
Dna And Rna ◽  
Dna And Rna Synthesis
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