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Results for “protein biosynthesis”

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At least 19 recordsLinked to original sources
PubMed1977

On the control of ribosomal protein biosynthesis in Escherichia coli. I. Studies on ribosomal protein biosynthesis in amino acid-starved cells.

The rate of individual ribosomal protein synthesis relative to total protein synthesis has been determined in Escherichia coli rel+ and rel- cells, under valyltRNA deprivation. These strains have a temperature-sensitive valyl-tRNA synthetase. Starvation was obtained following transfer to the cells to non-permissive temperature. Ribosomal proteins were obtained by treatment of either total lysates of freeze-thawed lysozyme spheroplasts or ammonium sulphate precipitate of ribosomes, with acetic acid. Differential labelling of the ribosomal proteins was observed in both strains: proteins from the rel+ strain appear more labelled than those from the rel- strain, the rate of labelling of individual proteins being about the same in both strains. Moreover ribosomal proteins were found as stable during starvation as total protein. It is thus concluded that in starving cells individual ribosomal proteins are not synthesized at equal rates. This indicates that the synthesis of ribosomal proteins is not only under the control of the rel gene.

Amino Acids↗
PubMedDate not supplied

[RNA biosynthesis and regulation of protein biosynthesis in the liver of chicks with experimental coccidiosis].

The aim of this work was to investigate the interrelationship between RNA biosynthesis and that of protein in chick liver during experimental coccidiosis induced by E. tenella. The peculiarity of this model is that in the course of this disease protein synthesis is significantly intensified inspite of the fact that the rate of the biosynthesis is rather high under normal conditions. It has been shown that 4 to 6 days after infection incorporation of labeled amino acids into proteins from chick liver subcellular fractions is greatly increased. The most pronounced changes are in ribosomal and mitochondrial fractions as well as in the postribosomal supernatant. At the same time the specific radioactivity of serum albumin excreted by liver was increased by factor 3. These changes in protein biosynthesis are associated with a significant increase of both the content and intensity of biosynthesis of high molecular weight precursors of rRNA as well as with those of mature 18S rRNA. The amount of 28S rRNA and mRNA per cell is practically without any changes whereas the mRNA turnover is somewhat more extensive. The selective accumulation of 18S rRNA is suggested to be responsible for the intensification of protein biosynthesis.

Animals↗
PubMed1975

Separation of myocardial cytoplasmic acidic inhibitor proteins which inhibit hepatic protein biosynthesis in vitro.

Cytoplasmic inhibitor proteins of rabbit and pig myocardium have been separated and their in-vitro effects on hepatic cell-free protein biosynthesis reported. Three protein peaks could be separated from myocardial cytoplasmic pH 5 fraction by DEAE and CM cellulose column chromatography. There was a difference in the elution pattern of the acidic inhibitor proteins obtained from pig and rabbit myocardium. The myocardial acidic inhibitor proteins inhibited a liver cell-free protein biosynthesizing system, but not a myocardial cell-free system.

Amino Acids↗
PubMedDate not supplied

[Study of the ultrastructural and functional expression of the hepatocyte genome under conditions of prolonged depression of protein biosynthesis by cycloheximide. III].

Dynamics of changes in mtRNA synthesis and mitochondria ultrastructure is strictly dependent on the level of inhibition of biosynthesis of cytoplasm proteins and "soluble" proteins of mitochondria by cycloheximide in hepatocytes: 1-6 hrs later a progressive weakening of protein synthesis is accompanied by a drop in mtRNA synthesis and essential destruction of mitochondria; from 12 to 24 hrs a partial restoration of protein biosynthesis induces the processes of the above-mentioned indexes normalization.

Animals↗
PubMedDate not supplied

[Factors participating in regulation of protein biosynthesis].

Studies in the processes of protein biosynthesis regulation revealed a close dependence of the biosynthetic processes (synthesis of many precursors of proteins, nucleic acids, lipids, carbohydrates as well as of tricarboxylic cycle acids) on the processes of carboxylation in the organism. A possibility is shown of the biosynthetic processes stimulation by activating the carboxylation processes. On this bases a highly effective method to increase productivity of farm animals and poultry and that for considerable acceleration of the regeneration processes of the damaged tissues and blood with blood less were developed. It is also established that at extremal states of the organism (long complete fasting, late stages of cancer, thyreoid toxicosis, experimental atherosclerosis, etc.) in tissues there occurs biosynthesis of proteins with differing primary structure, physiochemical properties and enzymatic activity as compared to proteins of the normal animals. The same changes in the primary structure and properties of proteins in the process of their biosynthesis are observed with the surplus feeding the animals on certain amino acids aginst a background of protein free ration. Possible mechanisms of changes in the primary structure of proteins in the process of their biosynthesis at extremal states of the organism are under discussion. In experiments in vitro on the tissue preparations, on the cell-free protein-synthetizing systems as well as in experiments with animals in vivo the presence of synergic and antagonistic interrelation was established between certain amino acids in the process of their utilization for protein biosynthesis. These interrelations are established to take place at the stage of transfer ribonucleic acids aminoacylation. Some details of this phenomenon are found out. Amino acids are shown to play not only a substrate role but also the regulatory one in the process of protein biosynthesis.

Amino Acids↗
PubMedDate not supplied

[Protein biosynthesis in a cell-free protein synthesis system from nodular euthyroid goiter cells].

Analysis of proteins, synthesized in cell-free system using nodal euthyroid goiter, was carried out by polyacrylamide gel disc electrophoresis. Four protein farctions, incorporating labelled amino acids, were found: "complete" thyroglobulin, two its subunits and thyroalmbumin. This correlates with the concept that malignant cell synthesizes intensively proteins untypical for a normal tissue.

Albumins↗
PubMed1977

[Role of protein biosynthesis activation in the mechanism of the negative chronotropic action of the vagus nerve and acetylcholine on the heart].

In rats, the following data were obtained: a) acetylcholine activates the rate of protein biosynthesis in auricles in vitro; b) protein biosynthesis inhibitors (actinomycine D, sarcolysine, neutral rot, tolluidine blue) weaken the negative chronotropic effect of acetylcholine and vagus on the heart; c) anabolic hormones increase the cholinergic effect on heart; d) acetylcholine induces hyperpolarization of the myocardial fibers which is prevented by actinomycine D. The activation of protein biosynthesis followed by hyperpolarization of the pacemaker cells seems to play an important role in the mechanism of negative chronotropic effect of acetylcholine and vagus on the heart.

Acetylcholine↗
PubMed1975

[Effect of the replication of rubella virus on the protein biosynthesis of BHK 21 cell cultures].

The protein biosynthesis of BHK-21/C 13 cell cultures under the influence of multiplying rubella virus was studied by the uptake and incorporation of 14C leucine. The uptake of 14C leucine by the cells of virus-infected cultures was found to increase up to the third day after infection; no further increase was detectable on the fourth day. Control cultures maintained under the same conditions showed a similar behaviour up to the second and on the fourth day. On the third day, the virus-infected cultures exhibited significantly higher uptake than the controls. It may be that the virus infection causes damage to the cellular wall, the nature of which has yet to be elucidated. The protein incorporation of 14C leucine slightly increases in the virus-infected cultures 36 hrs after infection. This increase is not equally pronounced in the control cultures, but the differences were not significant.

Cell Line↗
PubMed1979

Protein biosynthesis in isolated human scalp hair follicles.

The present study demonstrates that protein biosynthesis can be studied in single isolated human scalp hair follicles. The matrix and the sheath are the main regions where amino acids are built in. Incorporation is linear for at least five hours. The newly synthesized proteins can be separated into a water-soluble, a urea-soluble and a urea-insoluble fraction. Product analysis has been performed on the first two fractions, revealing different protein patterns.

Electrophoresis, Polyacrylamide Gel↗
PubMed1976

Studies on the mechanism of action of potassium iodide on thyroid protein biosynthesis.

Potassium iodide (KI) has been shown to have an antigoitrogenic action and to inhibit in vivo thyroid protein biosynthesis. Beef thyroid slices were used to clarify further the mechanism of action of KI. Incubations were performed in Krebs-Ringer-bicarbonate (KRB) buffer under 95%O2 and 5% CO2. KI caused a slight decrease in the uptake of [3H]eucine by the tissue. When labelled leucine incorporation into protein was measured it was found that 10(-6) M KI caused a marked inhibition. Increasing concentrations of KI up to 10(-3) M did not further increase this inhibition. This effect of KI was reduced by simultaneous addition of 0.5 mM KClO4 or 1 mM methylmercaptoimidazole (MMI). In several experiments it was found that equimolar amounts of thyroxine (T4) or triiodothyronine (T3) were more potent than KI in inhibiting thyroid protein biosynthesis. In double plabelled studies KI decreased [3H]leucine incorporation into thyroid soluble proteins and into immunoprecipitable thyroglobulin (T4) while it did not modify that of [14C]galactosamine. When tissue specificity was examined, KI failed to alter [3H]leucine incorporation into proteins either in the liver or in the submaxillary gland. The present results indicate that intracellular KI is necessary to exert its effect on protein synthesis, and that this effect is mediated through a organic form of iodine, probably iodothyronines. This action of KI is specific for the thyroid gland.

Animals↗
PubMedDate not supplied

[Effect of acetylcholine on protein biosynthesis in regions of the heart in adult and old rats].

Effect of acetylcholine on incorporation of labelled amino acids (14C hydrolysate of chlorella protein) into the free amino acid pool and total protein was studied using slices of auricles, right and left heart ventricles, obtained from 2-month, 8--10 month and 26--28-month old rats. Changes in the intensity of protein biosynthesis were estimated by following relative specific activity (RSA--protein specific activity/free amino acid pool specific activity). Maximal increase in the RSA value was found: in auricles of 2-month old rats in presence of 2.5.10(-4) M acetylcholine, in adult rats--in presence of 1.10(-3) M acetylcholine and in old rats--in presence of 5.10(-4) M acetylcholine; in right ventricle of all age groups--at the concentration of 1.10(-5) M acetylcholine. In left ventricle of all age groups the changes in RSA value were statistically unsignificant. Atropine blocked the stimulating effect of acetylcholine on protein biosynthesis in auricles.

Acetylcholine↗
PubMedDate not supplied

[RNA biosynthesis in mitochondria under conditions of prolonged inhibition of protein biosynthesis in rat liver cytoplasm].

When cytoplasmic protein synthesis is inhibited by cycloheximide (CHI) in vivo synthesis of water-soluble mitochondrial proteins and of mitochondrial RNA is decreased. These changes measured in isolated rat liver mitochondria are similar to those observed in vivo and correlate with the changes the synthesis of water-soluble proteins in mitochondria. When the cytoplasmic fraction (30,000 g-supernatant) had been added to the mitochondria showing decreased RNA synthesis, the RNA synthesis increased to the control level (the incubation conditions were favourable for the protein transport from microsomes to mitochondria). RNA synthesis in mitochondria was not stimulated by cytoplasmic fractions from the CHI-pretreated rats. After prolonged dialysis these fraction stimulated RNA synthesis even to a greater extent than cytoplasmic fractions from the untreated animals. Mitochondrial RNA polymerase activity (measured in mitochondrial extracts supplemented with exogenous DNA) was higher in extracts of mitochondria from livers of normal rats than in extracts of mitochondria from livers of animals injected with CHI.

Animals↗
PubMed1977

Compartmentation of free amino acids for protein biosynthesis. Influence of diurnal changes in hepatic amino acid concentrations of the composition of the precursor pool charging aminoacyl-transfer ribonucleic acid.

To investigate further the mechanisms by which amino acids are segregated for protein biosynthesis, the distribution of a pulse of [3H]valine was monitored in hepatic amino acid pools at seven intervals in the diurnal cycle of meal-fed rats. Although each condition was characterized by a unique balance between intracellular and extracellular valine, in every case the specific radioactivity of valyl-tRNA at steady state was higher that that of intracellular valine but below the extracellular value. Further, the specific radioactivity of the valyl-tRNA could be accurately predicted if extracellular and intracellular valine were combined in proportions specified by the transmembrane concentration gradient. These observations not only substantiate our earlier conclusions that the amino acids used for protein synthesis do not originate exclusively from either the intracellular or extracellular pools, but also strengthen our theory that the membrane transport system is the physical basis for such compartmentation. On the basis of these data we present a method for measuring the specific radioactivity of the precursor pool for protein biosynthesis in cases where the actual isolation of the aminoacyl-tRNA is not technically feasible, and also suggest a theoretical basis for interpreting the unequal distribution of both total and [3H]valine between intracellular and extracellular fluids.

Amino Acids↗
PubMed1975

The effects of polyamines on cardiac protein biosynthesis.

Putrescine, spermine, and spermidine were able to stimulate cell-free protein biosynthesis at low Mg++ ion concentrations. The addition of polyamines to the perfusate of an isolated perfused rat heart preparation caused an increased rate of [14C]phenylalanine incorporation into myocardial protein. Spermine increased the uptake of alpha-aminoisobutyric acid into the myocardium.

Aminoisobutyric Acids↗
PubMedDate not supplied

[Nucleic acid and protein biosynthesis in the accessory sex organs of rats during blockade of testosterone effect by androgen antagonist 4-nitro-3-trifluoromethylisobutyranilide].

The influence of testosterone and antiandrogen 4-nitro-3-trifluoromethylisobutyranilide (4N3TFMIBA) on the content and biosynthesis of nucleic acids and the protein in the ventral prostate and the seminal vesicles of Wistar rats was studied under experimental conditions. As revealed, with the simultaneous administration of the androgen and its antagonist there was a fall in the organs under study of the RNA and protein content and a reduction of incorporation of labeled precursors into the DNA, RNA, and protein. Similar changes were seen after castration. A conclusion was drawn that the capacity to block the stimulating influence of testosterone on the nucleic acid and protein biosynthesis underlay "castration" effects of antiandrogen 4N3TFMIBA, this causing atrophy of the accessory genital apparatus.

Anilides↗
PubMed1977

[Studies on protein biosynthesis in the silk gland of Bombyx mori L. silkworm].

The incorporation of (14C) lysine (to characterize the biosynthesis of cellular proteins) and (14C) glycine (for silk fibroin) in free and membrane-bound polyribosomes was studied in fibroin portion of the silk gland of Bombyx mori silkworm in the V instar. It was shown that although the membrane-bound polyribosomes are found in posterior silk gland from the beginning of the V instar, the fibroin biosynthesis in the membranebound polyribosomes takes place predominantly in the second part of the V instar. On the other hand the cellular proteins are synthesized mostly in the free polyribosomes in the first half of the V instar. In the second half of the V instar in the sucrose gradient zone corresponding to free polyribosomes, monoribosomes unable to synthesize protein for the absence of mRNA are present. Nevertheless, these ribosomes isolated from the fibroin part of the silk gland in the end of the V instar do synthesize polyphenylalanine in the presence of poly (U), and aminoacyl-t-RNA-synthetases and tRNA's obtained from the posterior silk gland.

Amino Acyl-tRNA Synthetases↗
PubMed1976

[On the molecular biology of the ageing. VI. Information. Changes of the protein biosynthesis in the age (author's transl)].

1. Most reports in the literature describe a diminished protein synthesis in the old organism. 2. The diminished protein synthesis may be the result of changes of ribosomes, unequal concentration of endogen m-RNA, changes of the activity or concentration of cytosol factors, especially the influence of SH-substances. 3. The age-dependent changes of protein biosynthesis are dependent on the technique of preparation and on the nutrition state of the organism. 4. Addition of 2-mercaptoethanol during preparation or to the incubation medium decreases the age-dependent differences of protein synthesis.

Aging↗