EFFECT OF IODIDE AND THYROTROPHIN ON IN VITRO 14C-AMINO ACID INCORPORATION INTO RAT THYROID PROTEINS

1974 ◽  
Vol 76 (2) ◽  
pp. 273-285 ◽  
Author(s):  
Lubomir J. Valenta
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Relative Concentration ◽  
Total Radioactivity ◽  
Amino Acid Incorporation ◽  
Control Value ◽  
Acid Incorporation ◽  
Rat Thyroid

ABSTRACT Thyroid lobes from rats on normal (NID) or low iodine (LID) intake were incubated for 4 hours in vitro in the presence of 14C-amino acids. The 14C-amino acid incorporation into thyroid protein was significantly higher in thyroids from LID than from NID fed rats, 7.82 ± 1.01 % (mean ± sd) of total radioactivity of the incubation mixture per 100 mg tissue compared to 3.74 ± 0.60 % respectively. Thyrotrophin (TSH) in vitro did not influence the 14C-amino acid incorporation. Iodide in concentration 10−7 m and higher decreased 14C-radioactivity incorporation into protein by 19.40 ± 3.06 and 26.59 ± 4.06 % of the control value for NID and LID rats respectively. This effect of iodide did not depend on iodine organification and was not influenced by the changes of free amino acids pool. There were no significant differences in the relative concentration of 14C-labelled thyroglobulin and total 14C-thyroid protein. Differential fragility demonstrable by unfolding or dissociation was observed between different classes of thyroglobulin. The fragility was increasing from the old non-labelled molecules to newly iodinated and newly synthesized ones. It is concluded that iodide has a direct intrathyroidal blocking effect on thyroid protein synthesis which may contribute to its antigoitrogenic action. The lack of in vitro stimulation of protein synthesis by TSH remains unexplained.

Effect of Cycloheximide on In Vitro and In Vivo Protein Synthesis by Certain Tissues of Rats and Pigeons with Special Reference to Muscle

1973 ◽  
Vol 51 (12) ◽  
pp. 933-941 ◽  
Author(s):  
Njanoor Narayanan ◽  
Jacob Eapen
Keyword(s):  
Amino Acids ◽  
Body Weight ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Incorporation ◽  
Contrast Administration ◽  
Acid Incorporation ◽  
Tissue Homogenates

The effect of cycloheximide in vitro and in vivo on the incorporation of labelled amino acids into protein by muscles, liver, kidneys, and brain of rats and pigeons was studied. In vitro incorporation of amino acids into protein by muscle microsomes, myofibrils, and myofibrillar ribosomes was not affected by cycloheximide. In contrast, administration of the antibiotic into intact animals at a concentration of 1 mg/kg body weight resulted in considerable inhibition of amino acid incorporation into protein by muscles, liver, kidneys, and brain. This inhibition was observed in all the subcellular fractions of these tissues during a period of 10–40 min after the administration of the precursor. Tissue homogenates derived from in vivo cycloheximide-treated animals did not show significant alteration in in vitro amino acid incorporation with the exception of brain, which showed a small but significant enhancement.

scholarly journals Action of growth hormone in vitro on the net uptake and incorporation into protein of amino acids in muscle from intact rabbits given protein-deficient diets

1976 ◽  
Vol 35 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. R. Turner ◽  
P. J. Reeds ◽  
K. A. Munday
Keyword(s):  
Amino Acids ◽  
Growth Hormone ◽  
Protein Synthesis ◽  
Amino Acid ◽  
De Novo ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Amino Acid Incorporation ◽  
Acid Incorporation

1. Net amino acid uptake, and incorporation into protein have been measured in vitro in the presence and absence of porcine growth hormone (GH) in muscle from intact rabbits fed for 5 d on low-protein (LP), protein-free (PF) or control diets.2. In muscle from control and LP animals GH had no effect on the net amino acid uptake but stimulated amino acid incorporation into protein, although this response was less in LP animals than in control animals.3. In muscle from PF animals, GH stimulated both amino acid incorporation into protein and the net amino acid uptake, a type of response which also occurs in hypophysectomized animals. The magnitude of the effect of GH on the incorporation of amino acids into protein was reduced in muscle from PF animals.4. The effect of GH on the net amino acid uptake in PF animals was completely blocked by cycloheximide; the uptake effect of GH in these animals was dependent therefore on de novo protein synthesis.5. It is proposed that in the adult the role of growth hormone in protein metabolism is to sustain cellular protein synthesis when there is a decrease in the level of substrate amino acids, similar to that which occurs during a short-term fast or when the dietary protein intake is inadequate.

EFFECTS OF DIHYDROSTREPTOMYCIN ON AMINO ACID INCORPORATION INTO THE PROTEINS OF M. TUBERCULOSIS (BCG)

1959 ◽  
Vol 37 (1) ◽  
pp. 687-697
Author(s):  
E. Stachiewicz ◽  
J. H. Quastel
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Sodium Stearate ◽  
Ehrlich Ascites Carcinoma ◽  
Inhibitory Effect ◽  
Total Radioactivity ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Drug Concentrations

A study has been made of the effects of dihydrostreptomycin on amino acid incorporation into the proteins of M. tuberculosis (BCG). Suspensions of this organism on incubation at 37° with glycine-1-C14give rise, aerobically, to labelled proteins in which 80% of the radioactivity appears in the glycine and serine moieties of the proteins and about 20% in alanine and aspartic acid. In presence of glycine-2-C14, radioactivity appears in a larger number of amino acids of the protein. Incubation with serine-3-C14leads to a distribution of radioactivity in the amino acids in BCG proteins but alanine-1-C14and valine-1-C14give rise to proteins with the radioactivity almost entirely in the corresponding amino acids. The process of aerobic incorporation of radioactivity from glycine-1-C14in BCG proteins is stimulated by the presence of glucose, glycerol, sodium pyruvate, sodium stearate, or sodium benzoate in the medium in which the cells are incubated, the rate of incorporation being approximately constant over a period of 4 hours. The incorporation depends largely on the presence of oxygen. Dihydrostreptomycin (33 μg per ml) markedly inhibits labelling of proteins in the cell suspensions in presence of radioactive amino acids, the inhibition increasing with concentration of the streptomycin to an optimal concentration of 200 μg/ml. Penicillin and isonicotinic hydrazide are inactive but chloromycetin is an effective inhibitor. Cyanide, arsenite, and azide are inhibitory. The presence of lecithin stimulates incorporation of radioactivity from glycine-1-C14into BCG proteins. Dihydrostreptomycin inhibitions of amino acid incorporation into BCG proteins increase with time of incubation of the cells with the drug. Concentrations of dihydrostreptomycin that inhibit labelled amino acid incorporation into labelled proteins by 50% have no effect on BCG respiration. The drug has no inhibitory effect on labelled amino acid incorporation in E. coli or Ehrlich ascites carcinoma cells in vitro but is effective with M. phlei. It does not affect selectively the distribution of radioactivities of the component amino acids of BCG proteins; only the total radioactivity incorporated into the proteins is diminished. The results lead to the conclusion that dihydrostreptomycin brings about an inhibition of protein synthesis in the BCG strain of M. tuberculosis at concentrations at which it exerts antibiotic effects.

EFFECTS OF DIHYDROSTREPTOMYCIN ON AMINO ACID INCORPORATION INTO THE PROTEINS OF M. TUBERCULOSIS (BCG)

1959 ◽  
Vol 37 (5) ◽  
pp. 687-697 ◽  
Author(s):  
E. Stachiewicz ◽  
J. H. Quastel
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Sodium Stearate ◽  
Ehrlich Ascites Carcinoma ◽  
Inhibitory Effect ◽  
Total Radioactivity ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Drug Concentrations

A study has been made of the effects of dihydrostreptomycin on amino acid incorporation into the proteins of M. tuberculosis (BCG). Suspensions of this organism on incubation at 37° with glycine-1-C14give rise, aerobically, to labelled proteins in which 80% of the radioactivity appears in the glycine and serine moieties of the proteins and about 20% in alanine and aspartic acid. In presence of glycine-2-C14, radioactivity appears in a larger number of amino acids of the protein. Incubation with serine-3-C14leads to a distribution of radioactivity in the amino acids in BCG proteins but alanine-1-C14and valine-1-C14give rise to proteins with the radioactivity almost entirely in the corresponding amino acids. The process of aerobic incorporation of radioactivity from glycine-1-C14in BCG proteins is stimulated by the presence of glucose, glycerol, sodium pyruvate, sodium stearate, or sodium benzoate in the medium in which the cells are incubated, the rate of incorporation being approximately constant over a period of 4 hours. The incorporation depends largely on the presence of oxygen. Dihydrostreptomycin (33 μg per ml) markedly inhibits labelling of proteins in the cell suspensions in presence of radioactive amino acids, the inhibition increasing with concentration of the streptomycin to an optimal concentration of 200 μg/ml. Penicillin and isonicotinic hydrazide are inactive but chloromycetin is an effective inhibitor. Cyanide, arsenite, and azide are inhibitory. The presence of lecithin stimulates incorporation of radioactivity from glycine-1-C14into BCG proteins. Dihydrostreptomycin inhibitions of amino acid incorporation into BCG proteins increase with time of incubation of the cells with the drug. Concentrations of dihydrostreptomycin that inhibit labelled amino acid incorporation into labelled proteins by 50% have no effect on BCG respiration. The drug has no inhibitory effect on labelled amino acid incorporation in E. coli or Ehrlich ascites carcinoma cells in vitro but is effective with M. phlei. It does not affect selectively the distribution of radioactivities of the component amino acids of BCG proteins; only the total radioactivity incorporated into the proteins is diminished. The results lead to the conclusion that dihydrostreptomycin brings about an inhibition of protein synthesis in the BCG strain of M. tuberculosis at concentrations at which it exerts antibiotic effects.

scholarly journals FRUCTOSE-AMINO ACIDS IN LIVER: STIMULI OF AMINO ACID INCORPORATION IN VITRO

1955 ◽  
Vol 215 (1) ◽  
pp. 111-124 ◽  
Author(s):  
Henry Borsook ◽  
Adolph Abrams ◽  
Peter H. Lowy
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Incorporation ◽  
Acid Incorporation

scholarly journals Biotin-mediated protein biosynthesis

1974 ◽  
Vol 140 (3) ◽  
pp. 549-556 ◽  
Author(s):  
R. L. Boeckx ◽  
K. Dakshinamurti
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Rat Liver ◽  
Intestinal Mucosa ◽  
Protein Biosynthesis ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Stimulation Of

The effect of administration of biotin to biotin-deficient rats on protein biosynthesis was studied. Biotin treatment resulted in stimulation by more than twofold of amino acid incorporation into protein, both in vivo and in vitro in rat liver, pancreas, intestinal mucosa and skin. Analysis of the products of amino acid incorporation into liver proteins in vivo and in vitro indicated that the synthesis of some proteins was stimulated more than twofold, but others were not stimulated at all. This indicates a specificity in the stimulation of protein synthesis mediated by biotin.

Incorporation of C14-amino acids into protein of isolated diaphragms: effect of epinephrine and norepinephrine

1960 ◽  
Vol 198 (1) ◽  
pp. 54-56 ◽  
Author(s):  
Ira G. Wool
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glucose Concentration ◽  
Muscle Protein ◽  
Effective Concentration ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Minimal Effective Concentration

When diaphragms isolated from normal rats were incubated with a C14-amino acid the addition of epinephrine or norepinephrine decreased incorporation of C14 into muscle protein. The inhibition occurred whether epinephrine was added in vitro or administered in vivo. The minimal effective concentration of epinephrine in vitro was 0.1 µg/ml. When the glucose concentration in the medium was raised to 300 mg % or more the epinephrine induced inhibition of amino acid incorporation into muscle protein was no longer observed.

scholarly journals PROTEIN SYNTHESIS IN ISOLATED CELL NUCLEI

1957 ◽  
Vol 40 (3) ◽  
pp. 451-490 ◽  
Author(s):  
V. G. Allfrey ◽  
A. E. Mirsky ◽  
Syozo Osawa
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Ribonucleic Acid ◽  
Orotic Acid ◽  
Nuclear Protein ◽  
Acid Uptake ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Thymus Tissue

1. Nuclei prepared from calf thymus tissue in a sucrose medium actively incorporate labelled amino acids into their proteins. This is an aerobic process which is dependent on nuclear oxidative phosphorylation. 2. Evidence is presented to show that the uptake of amino acids represents nuclear protein synthesis. 3. The deoxyribonucleic acid of the nucleus plays a role in amino acid incorporation. Protein synthesis virtually ceases when the DNA is removed from the nucleus, and uptake resumes when the DNA is restored. 4. In the essential mechanism of amino acid incorporation, the role of the DNA can be filled by denatured or partially degraded DNA, by DNAs from other tissues, and even by RNA. Purine and pyrimidine bases, monoribonucleotides, and certain dinucleotides are unable to substitute for DNA in this system. 5. When the proteins of the nucleus are fractionated and classified according to their specific activities, one finds the histones to be relatively inert. The protein fraction most closely associated with the DNA has a very high activity. A readily extractable ribonucleoprotein complex is also extremely active, and it is tempting to speculate that this may be an intermediary in nucleocytoplasmic interaction. 6. The isolated nucleus can incorporate glycine into nucleic acid purines, and orotic acid into the pyrimidines of its RNA. Orotic acid uptake into nuclear RNA requires the presence of the DNA. 7. The synthesis of ribonucleic acid can be inhibited at any time by a benzimidazole riboside (DRB) (which also retards influenza virus multiplication (11)). 8. The incorporation of amino acids into nuclear proteins seems to require a preliminary activation of the nucleus. This can be inhibited by the same benzimidazole derivative (DRB) which interferes with RNA synthesis, provided that the inhibitor is present at the outset of the incubation. DRB added 30 minutes later has no effect on nuclear protein synthesis. These results suggest that the activation of the nucleus so that it actively incorporates amino acids into its proteins requires a preliminary synthesis of ribonucleic acid. 9. Together with earlier observations (27, 28) on the incorporation of amino acids by cytoplasmic particulates, these results show that protein synthesis can occur in both nucleus and cytoplasm.

In vitro protein synthesis directed by R17 viral ribonucleic acid. II. On the fate of mRNA in the cell-free system

1969 ◽  
Vol 47 (12) ◽  
pp. 1179-1186 ◽  
Author(s):  
Satomi J. Igarashi
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid Incorporation ◽  
Free System ◽  
Cell Free System ◽  
E Coli ◽  
Acid Incorporation ◽  
Binding Factor ◽  
Vitro Protein

In the crude E. coli B cell-free system, mRNA was hydrolyzed by contaminating nuclease activities before significant polymerization of amino acids took place. Ribosomes appeared to be one of the sources of nuclease. A modified high-salt washing procedure was developed to remove nuclease from ribosomes. RNase-free ribosomes thus obtained appeared to be inactive in poly-U-directed phenylalanine incorporation, unless poly-U binding factor was added to the system. R17 RNA could not direct amino acid incorporation in the presence of RNase-free ribosomes because binding of intact R17 RNA to ribosomes did not take place even in the presence of poly-U binding factor.

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