scholarly journals SYNTHESIS OF MESSENGER-LIKE RIBONUCLEIC ACID AND PROTEIN DURING MEIOSIS IN ISOLATED CELLS OF TRILLIUM ERECTUM

1963 ◽  
Vol 19 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Yasuo Hotta ◽  
Herbert Stern
Keyword(s):  
Messenger Rna ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Morphological Changes ◽  
Reaction Rates ◽  
Meiotic Stage ◽  
Isolated Cells ◽  
Rna Analysis ◽  
Protein And Rna Synthesis

The synthesis of RNA and protein by cultures of isolated microsporocytes has been demonstrated. The variation in capacities of such cultures to perform syntheses is a function of meiotic stage and parallels the pattern of changes observed for microsporocytes in situ. A principal feature of this pattern is the induction of syntheses during pachytene and diplotene, stages at which the chromosomes are partly contracted. By use of Actinomycin D, chloramphenicol, pulse-labeling with P32-phosphate, and nucleotide analyses of RNA digests, part of the RNA synthesized has been shown to correspond to messenger RNA. Analysis of reaction rates and the overlappings of protein and RNA synthesis indicates that the spread of cytological events in Trillium is not purely a function of the low temperature at which it occurs but, presumably, arises from a complement of regulatory devices which govern the periodic onset of reactions within the cells. The main conclusion drawn from the whole of these studies is that the sequence of morphological changes associated with chromosome contraction and movement during meiosis is accompanied by a set of gene transcriptions. Although comparatively few genes are presumed to be active during meiosis, the action of such genes may be essential to a translation of some of the information embodying the meiotic sequence which has been stored in the genome in the course of evolution.

Effect of Some Metabolic Inhibitors on Vinblastine-Induced Ribosomal-Granular Material Complexes

1971 ◽  
Vol 29 ◽  
pp. 548-549
Author(s):  
Awtar Krishan ◽  
Dora Hsu
Keyword(s):  
Granular Material ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Actinomycin D ◽  
Metabolic Inhibitors ◽  
Protein And Rna Synthesis ◽  
Apparent Reduction ◽  
Plant Alkaloids ◽  
In Cells

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).

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 PROTEIN SYNTHESIS AND RNA SYNTHESIS DURING MITOSIS IN ANIMAL CELLS

1963 ◽  
Vol 19 (2) ◽  
pp. 267-277 ◽  
Author(s):  
Carol G. Konrad
Keyword(s):  
Protein Synthesis ◽  
Messenger Rna ◽  
Rna Synthesis ◽  
Animal Cells ◽  
Drastic Reduction ◽  
Human Amnion ◽  
Culture Cells ◽  
Cent Increase ◽  
Protein And Rna Synthesis ◽  
Synthetic Capacity

Protein synthesis and RNA synthesis during mitosis were studied by autoradiography on mammalian tissue culture cells. Protein synthesis was followed by incubating hamster epithelial and human amnion cells for 10 or 15 minutes with phenylalanine-C14. To study RNA synthesis the hamster cells were incubated for 10 minutes with uridine-C14. Comparisons of the synthetic capacity of the interphase and mitotic cells were then made using whole cell grain counts. The rate of RNA synthesis decreased during prophase and reached a low of 13 to 16 per cent of the average interphase rate during metaphase-anaphase. Protein synthesis in the hamster cells showed a 42 per cent increase during prophase with a subsequent return to the average interphase value during metaphase-anaphase. The human amnion cells showed no significant change at prophase but there was a 52 to 56 per cent drop in phenylalanine incorporation at metaphase-anaphase as compared to the average interphase rate. Colcemide was used on the hamster cells to study the effect of a prolonged mitotic condition on protein and RNA synthesis. Under this condition, uridine incorporation was extremely low whereas phenylalanine incorporation was still relatively high. The drastic reduction of RNA synthesis observed under mitotic conditions is believed to be due to the coiled condition of the chromosomes. The lack of a comparable reduction in protein synthesis during mitosis is interpreted as evidence for the presence in these cells of a relatively stable messenger RNA.

GIBBERELLIN, AS A REGULATOR OF PROTEIN AND RIBONUCLEIC ACID SYNTHESIS DURING SENESCENCE IN LEAF CELLS OF TARAXACUM OFFICINALE

1966 ◽  
Vol 44 (6) ◽  
pp. 739-745 ◽  
Author(s):  
R. A. Fletcher ◽  
Daphne J. Osborne
Keyword(s):  
Leaf Senescence ◽  
Ribonucleic Acid ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Acid Synthesis ◽  
Taraxacum Officinale ◽  
Leaf Discs ◽  
Protein And Rna Synthesis ◽  
Chlorophyll Protein ◽  
Gibberellin Treatment

The addition of gibberellin A3 (GA) to leaf discs of Taraxacum officinale Weber retards their senescence and delays the decline in the levels of chlorophyll, protein, and RNA. Incorporation of 14C leucine and 14C adenine into protein and RNA respectively was increased by GA. This enhancement of protein and RNA synthesis did not occur if the discs were supplied with actinomycin D before treatment with gibberellin. If, however, actinomycin D was added after the gibberellin treatment then the stimulatory effect of the hormone was maintained. These results suggest that the retarding action of gibberellins on leaf senescence could be mediated through a regulation of RNA synthesis that is DNA dependent.

FIBRIN STIMULATION OF ENDOTHELIAL CELL (EC) PRODUCTION OF PGI AND TISSUE PLASMINOGEN ACTIVATOR (t-PA)

1987 ◽  
Author(s):  
L K Kaplan ◽  
T Mather ◽  
L DeMarco ◽  
S Solomon
Keyword(s):  
Rna Synthesis ◽  
Actinomycin D ◽  
Umbilical Vein ◽  
Cytochalasin D ◽  
Time Dependent ◽  
Time Intervals ◽  
Tissue Plasminogen ◽  
Protein And Rna Synthesis ◽  
Maximal Production ◽  
Stimulation Of

Many substances are known to stimulate EC production of PGI2 and t-PA. Additionally, it has been reported that fibrin can Be formed on the EC surface. In this study, the possibility that fibrin generated on the surface of cells can stimulate production of PGI2 and t-PA was examined. Human umbilical vein ECs were incubated for various time intervals with citrated human plasma clotted on the cells by the addition of CaCl2 . Control dishes contained plasma without Ca++ or serum. Time-dependent generation of PGI2 and t-PA was seen over 22-24 hours. Maximal production of PGI2 occurred when fibrin on the cells was formed from 10 to 50% plasma, with serum comprising the remainder of the incubation volume, while maximal t-PA production occurred with clots formed from 100% plasma. Fibrin I formed by addition of batroboxin to citrated plasma stimulated less synthesis of t-PA than did fibrin formed by thrombin action, and it did not stimulate PGI2 production. Thrombin clots were significantly more adherent to the cells than were batroboxin clots. PG^ synthesis induced by fibrin was fully inhibited by indomethacin, approximately 50% inhibited by actinomycin D and cycloheximide, and 20% inhibited by trifluoperazine, but was unaffected by cytochalasin D and vinblastine. Stimulation of t-PA synthesis by fibrin was unaffected by indomethacin, completely inhibited by actinomycin D and cycloheximide, and 60%, 80% and 40% blocked by cytochalasin D, vinblastine, and trifluoperazine, respectively. Thus, thrombin-induced fibrin clots stimulated PGI2 synthesis, and both thrombin and batroboxin clots stimulated t-PA synthesis. Protein and RNA synthesis were essential to stimulation of t-PA synthesis but inhibition of these processes only partially inhibited stimulation of PGI2 synthesis. Integrity of the cytoskeleton was necessary for full stimulation of t-PA synthesis, but not for stimulation of PGI2 synthesis. Thus the mechanisms of stimulation of these two cellular products were different. Increased PGI2 production could serve to limit further fibrin formation by preventing platelets from contributing to the coagulation process and increased t-PA could stimulate lysis of existing fibrin.

scholarly journals SYNTHESIS OF PLASMA MEMBRANE-ASSOCIATED AND SECRETORY IMMUNOGLOBULIN IN DIPLOID LYMPHOCYTES

1972 ◽  
Vol 135 (1) ◽  
pp. 136-149 ◽  
Author(s):  
Richard A. Lerner ◽  
Patricia J. McConahey ◽  
Inga Jansen ◽  
Frank J. Dixon
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Plasma Membrane ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
G1 Phase ◽  
Synchronized Cells ◽  
Disappearance Time ◽  
Protein And Rna Synthesis ◽  
Secretory Immunoglobulin

The half disappearance time for detectable plasma membrane-associated and cytoplasmic immunoglobulin after treatment of continuously growing diploid lymphocytes with inhibitors of protein and RNA synthesis was studied. Also, the amount of plasma membrane-associated and cytoplasmic immunoglobulin of synchronized cells in the G1 phase of the cell cycle has been studied. Plasma membrane-associated immunoglobulin has a half disappearance time of 45 min after inhibition of protein synthesis. By contrast, after treatment of cells with actinomycin D for 24 hr, plasma membrane-associated immunoglobulin remains relatively unchanged whereas cytoplasmic immunoglobulin decreased by almost 90%. In the G1 phase of the cell cycle, plasma membrane-associated immunoglobulin and cytoplasmic immunoglobulin were 70 and 10%, respectively, of that in logarithmically growing cells, and the half disappearance of M-Ig after treatment of cells with puromycin was again 45 min. In toto, these results suggest that perhaps secreted and plasma membrane-associated immunoglobulin may be separately controlled by the cells.

Nature of the So-Called Fibrillar Component in the Segregated Nucleolus

1972 ◽  
Vol 30 ◽  
pp. 244-245
Author(s):  
T. Unuma ◽  
R. Senda ◽  
M. Muramatsu
Keyword(s):  
Rna Synthesis ◽  
Actinomycin D ◽  
Morphological Changes ◽  
Enzymatic Digestion ◽  
The Other ◽  
Granular Component ◽  
Fibrillar Component ◽  
Nucleolar Segregation ◽  
Nucleolar Components

Actinomycin D, selectively blocks DNA-dependent RNA synthesis, causes marked morphological changes of the nucleolus. One of the most prominent changes is the segregation of the nucleolar components. The granular component is redistributed and separated from the other components of the nucleolus. The term nucleolar segregation has been used to designate the separation of the granular and fibrillar components. In the present study, the nucleolus was segregated into two distinct zones, namely the granular and the so-called fibrillar component (Fig. 1). The purpose of this study is to present the evidences of protelnous nature of the so-called fibrillar component in the segregated nucleolus by morphological, biochemical and enzymatic digestion studies.

ACTION OF CYCLIC NUCLEOTIDES ON PROTEIN AND RNA SYNTHESIS IN THE THYROID

1977 ◽  
Vol 84 (2) ◽  
pp. 297-302 ◽  
Author(s):  
Mario A. Pisarev ◽  
Diana L. Kleiman de Pisarev
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Cyclic Nucleotides ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Soluble Fraction ◽  
Stimulatory Action ◽  
Protein And Rna Synthesis ◽  
Cyclic Cmp

ABSTRACT Thyrotrophin (TSH) regulates the biosynthesis of thyroid protein and RNA. This action is mediated by adenylate cyclase and cyclic AMP. In the present study the action of cyclic GMP and cyclic CMP was investigated in beef slices. Both cyclic AMP and cyclic GMP significantly increased the incorporation of [3H]uridine into RNA. These effects were blocked by actinomycin D, suggesting that their action is located at a preor at a transcriptional step. The PCA soluble fraction radioactivity followed in parallel with the variations observed in the RNA fraction, supporting the view that cyclic nucleotides may regulate RNA by modulating the nucleotide precursors pool. Cyclic CMP in concentrations between 0.35 to 1.5 mm progressively decreased the RNA labelling, and the values of the PCA soluble radioactivity again followed those of RNA. Furthermore, cyclic CMP also blocked the in vitro stimulatory action of cyclic AMP on the incorporation of [3H]leucine into protein, and of [3H]uridine into RNA. The present results provide the first information on the action of cyclic AMP on RNA synthesis and suggest that negative signals may also play a part in the regulation of thyroid function.

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