scholarly journals Anabolism versus catabolism of [5-3H]uridine and its relationship to ribonucleic acid labelling in mouse liver after partial hepatectomy

1979 ◽  
Vol 178 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Torsten Yngner ◽  
Claes Engelbrecht ◽  
Lillemor Lewan ◽  
Jan-Erik Annerfeldt
Keyword(s):  
Nucleic Acid ◽  
Partial Hepatectomy ◽  
Ribonucleic Acid ◽  
Mouse Liver ◽  
Rna Synthesis ◽  
Specific Radioactivity ◽  
Acid Synthesis ◽  
Liver Cells ◽  
Control Value

The balance between anabolism and catabolism of [5-3H]uridine was studied in the mouse after partial hepatectomy. Labelling of RNA and UDP-glucose was determined and evaluated in relation to changes in the specific radioactivity of UTP. The amounts of labelled catabolic products of uridine were increased several-fold in liver and blood after partial hepatectomy. The specific radioactivity of RNA decreased to about 60% of the control value at 6h and was in the same range as that of control liver at 24h after operation. Decreased labelling of RNA and UDP-glucose was attributable to decreased specific radioactivity of UTP. No changes in the size of the UTP pool or in the balance between uridine anabolism and catabolism were found that could explain the decreased specific radioactivity of UTP. Rather, the alterations in the labelling of this metabolite induced by the partial hepatectomy may be related to decreased phosphorylating capacity in the liver cells and/or dilution of the labelled precursor in an expanded uridine pool. The enhanced amounts of uridine catabolic products in liver and blood were probably a consequence of accumulation and altered incorporation of the metabolites from the blood into the liver cells. Despite the increased amounts of labelled catabolic products and the decreased labelling of RNA, the results reported here actually suggest decreased uridine catabolism and slightly increased RNA synthesis in mouse liver after partial hepatectomy. The results stress the importance of proper controls in determination of nucleic acid synthesis and in metabolic studies by use of labelled precursors.

Hormone-induced differentiation of antheridial branches in Achlya ambisexualis: dependence on ribonucleic acid synthesis

1974 ◽  
Vol 20 (7) ◽  
pp. 977-980 ◽  
Author(s):  
David K. Horowitz ◽  
Peter J. Russell
Keyword(s):  
Sexual Differentiation ◽  
Ribonucleic Acid ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Steroid Hormone ◽  
Acid Synthesis ◽  
Aquatic Fungus ◽  
Induced Differentiation ◽  
Sexual Steroid ◽  
Achlya Ambisexualis

Sexual differentiation in male strains of the aquatic fungus Achlya ambisexualis Raper is induced by antheridiol, a sexual steroid hormone secreted by female strains. Antheridiol-induced initiation of the morphologically distinct antheridial branches in male Achlya is completely prevented when DNA-dependent RNA synthesis is inhibited by actinomycin D. In addition antheridial branch elongation is inhibited to a degree proportional to the concentration of actinomycin D added. Thus, evidence indicates that RNA synthesis is required for antheridiol-induced initiation of antheridial branching and that continued RNA synthesis is required for elongation of antheridial branches.

Activité génétique au cours de l'embryogenèse de l'Oligochète Eisenia fœtida (autoradiographie à l'uracile-3H et traitement à l'actinomycine D)

Development ◽  
1976 ◽  
Vol 35 (2) ◽  
pp. 403-424
Author(s):  
Par J. Devriès
Keyword(s):  
Ribonucleic Acid ◽  
Actinomycin D ◽  
Acid Synthesis ◽  
Eisenia Foetida ◽  
Messenger Rnas ◽  
Blastula Stage ◽  
Stages Of Development ◽  
Interphase Nuclei ◽  
Nuclear Membranes

Embryos of Eisenia fœtida (Spiralia) have been cultivated with [3H]uracil precursor of RNA at different stages of development from egg to gastrula. The results show that ribonucleic acid synthesis detected by autoradiography begins precociously. During segmentation messenger RNAs are produced by interphase nuclei and liberated in cytoplasm cyclically at mitosis. After the blastula stage rRNAs (nucleoli), which can migrate through the nuclear membranes, predominate. The blastomeres, which contain polar plasm and also mesoderm, already known for its controlling part in embryogenesis after gastrulation, are the seats of the increasingly important ribonucleic acid synthesis. These genetic transcriptions, which are inhibited by actinomycin D, are implicated in the determination of the blastomeres and postblastular differentiation. Only the messages required for the segmentation divisions pre-exist in the undivided egg.

Protein and Nucleic Acid Syntheses in Dark-dormant Common Purslane(Portulaca oleracea)Seed

Weed Science ◽  
1978 ◽  
Vol 26 (6) ◽  
pp. 669-672 ◽  
Author(s):  
Bonnie J. Reger ◽  
Ida E. Yates
Keyword(s):  
Protein Synthesis ◽  
Nucleic Acid ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
Portulaca Oleracea ◽  
Dark Incubation ◽  
Radicle Protrusion ◽  
Lag Period ◽  
Common Purslane ◽  
H Protein

Dark-incubated common purslane(Portulaca oleraceaL.) seed synthesize very little protein and essentially no nucleic acids. Dark-incubated seed incorporate only 14 × 10−3nmoles14C-leucine/mg protein/12-h dark. In contrast, seed exposed to 12-h light following 24-h dark incubation incorporate 365 × 10−3-nmoles14C-leucine/mg protein/12-h light. Once dormancy is broken by exposure of seed to light, initiation of radicle protrusion occurs at 12 h. Protein synthesis gradually increases with time in the light and precedes nucleic acid synthesis which is associated with radicle protrusion. During the 12-h lag period preceding radicle protrusion protein synthesis increases significantly by 3 to 9 h in light, RNA synthesis by 9 h in light, and DNA synthesis by 12 h in light. After 12 h in light,32P can be detected in all nucleic acid fractions, DNA and RNAs.

scholarly journals Studies on the pathogenesis of liver necrosis by α-amanitin. Effect of α-amanitin on ribonucleic acid synthesis and on ribonucleic acid polymerase in mouse liver nuclei

1967 ◽  
Vol 105 (2) ◽  
pp. 779-782 ◽  
Author(s):  
F. Stirpe ◽  
L. Fiume
Keyword(s):  
Rna Polymerase ◽  
Ammonium Sulphate ◽  
Ribonucleic Acid ◽  
Mouse Liver ◽  
Orotic Acid ◽  
Acid Synthesis ◽  
Liver Necrosis ◽  
Liver Nuclei

1. Injection of α-amanitin to mice causes a decreased incorporation of [6−14C]-orotic acid into liver RNA in vivo. 2. The activity of RNA polymerase activated by Mn2+ and ammonium sulphate is greatly impaired in liver nuclei isolated from mice poisoned with α-amanitin, and is inhibited by the addition of the same toxin in vitro. 3. The activity of the Mg2+-activated RNA polymerase is only slightly affected by α-amanitin either administered to mice or added in vitro.

scholarly journals EFFECTS OF CORTISONE ON REGENERATING RAT LIVER

1954 ◽  
Vol 37 (4) ◽  
pp. 559-574 ◽  
Author(s):  
Stanley L. Einhorn ◽  
Erich Hirschberg ◽  
Alfred Gellhorn
Keyword(s):  
Nucleic Acid ◽  
Rat Liver ◽  
Acid Content ◽  
Acid Synthesis ◽  
Significant Degree ◽  
Liver Cells ◽  
Nucleic Acid Content ◽  
Cell Multiplication ◽  
Continuous Administration ◽  
Regenerating Rat Liver

The effects of continuous administration of cortisone on the metabolism of regenerating rat liver have been studied. Whereas the restoration of the weight of the liver after partial hepatectomy was not markedly affected by cortisone, the multiplication of cells was reduced to a significant degree after the first 2 days of regeneration. Liver restoration in terms of nucleic acids was similarly inhibited by cortisone. The results are consistent with the interpretation that the inhibition of cell multiplication in this system is dependent on and keeps pace with the inhibition of nucleic acid synthesis by this drug. At almost any time after hepatectomy, the nucleic acid content of the liver cells was the same in treated and in untreated animals. In ancillary studies, it was shown that cortisone caused the cells of regenerating liver to be increased in size and weight through the increased infiltration of lipids. Changes in water, protein, and carbohydrate content of the liver cells did not contribute to this increase in the weight of the cells. Since all animals were treated with cortisone for 5 days before hepatectomy, data were also obtained on the effect of this agent on the resting liver. This course of treatment brought about a significant decrease in the number of cells per unit wet weight and in the water content of the livers. The nucleic acid content of the cells at hepatectomy, on the other hand, was unchanged.

scholarly journals Decreased ribonucleic acid synthesis in isolated rat liver nuclei during starvation

1970 ◽  
Vol 120 (2) ◽  
pp. 381-384 ◽  
Author(s):  
D. Rickwood ◽  
H. G. Klemperer
Keyword(s):  
Rna Polymerase ◽  
Ammonium Sulphate ◽  
Ribonucleic Acid ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Acid Synthesis ◽  
Isolated Nuclei ◽  
Isolated Rat Liver ◽  
Liver Nuclei ◽  
Isolated Rat

1. Isolated nuclei from starved rats showed a lowered incorporation of [14C]UMP into RNA. 2. The Mg2+-dependent incorporation was decreased by 30% after 1 day of starvation, but incorporation in the presence of Mn2+ and ammonium sulphate decreased only after longer periods of starvation. 3. RNA synthesis by nuclei in the presence of excess of added RNA polymerase was unchanged after 1 day of starvation and was inhibited by 20% after 4 days. 4. The capacity of nuclei to bind actinomycin D was unchanged after 1 day and was decreased by 20% after 4 days of starvation.

Inhibition of nucleic acid synthesis in L1210 cells by nucleoside analogs

1984 ◽  
Vol 49 (11) ◽  
pp. 2551-2556 ◽  
Author(s):  
Jiří Beránek ◽  
Edward M. Acton
Keyword(s):  
Nucleic Acid ◽  
Rna Synthesis ◽  
Nucleoside Analogs ◽  
Acid Synthesis ◽  
Pyrimidine Nucleoside ◽  
Dna And Rna ◽  
L1210 Cells ◽  
Structure Activity ◽  
Dna And Rna Synthesis ◽  
Chloro Derivatives

Series of pyrimidine nucleoside analogs were tested for inhibition of DNA and/or RNA synthesis at L1210 cells. The structure-activity relationship was studied at the analogs of cancerostatic agents 5-fluorouracil and arabinosylcytosine. Out of them the 5'-chloro derivatives give some promise. The inhibitory activity of cyclocytidine vs DNA and RNA synthesis approaches the activity of cancerostatic antibotics.

scholarly journals RNA synthesis in regenerating mouse liver evaluated by incorporation of [methyl-14C]methionine and by determination of RNA polymerase activity

1984 ◽  
Vol 221 (1) ◽  
pp. 235-239 ◽  
Author(s):  
I Ljungquist ◽  
T Yngner ◽  
L Lewan ◽  
C Engelbrecht
Keyword(s):  
Rna Polymerase ◽  
Liver Regeneration ◽  
Partial Hepatectomy ◽  
Mouse Liver ◽  
Specific Radioactivity ◽  
Total Activity ◽  
Polymerase Activity ◽  
Rna Polymerase Activity ◽  
The Difference ◽  
Polymerase I

The synthesis of RNA during mouse liver regeneration was studied by two different methods at 24 and 48 h after partial hepatectomy. Total chromatin-bound RNA polymerase activity showed an increase of 32% at 24 h after partial hepatectomy. At 48 h a slight increase in total activity was also observed in regenerating liver, but the difference was not significant. The increase in total RNA polymerase activity was due to a rise in RNA polymerase I plus III activity. This enzyme activity was increased at both 24 and 48 h. The increase was 57% at 24 h and 51% at 48 h. When [methyl-14C]methionine was used for labelling of methyl groups in rRNA, there was an increased specific radioactivity of this class of RNA at both 24 h and 48 h. The increases were 263 and 103% at 24 and 48 h respectively. Thus both methods revealed an increased synthesis of rRNA during mouse liver regeneration. The results are discussed in relation to previous results from this laboratory [Yngner, Carlberg, Lewan & Engelbrecht (1979) Hoppe-Seyler's Z. Physiol. Chem. 360, 1069-1074; Yngner, Engelbrecht, Lewan & Annerfeldt (1979) Biochem. J. 178, 1-8; Yngner, Bengtsson, Carlberg, Engelbrecht & Wieslander (1980) Exp. Cell. Biol. 48, 393-403], which have shown that the incorporation of orotic acid or uridine into RNA is not increased in mouse liver regenerating after partial hepatectomy.

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