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Results for “Protein Biosynthesis”

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At least 73 records · Page 4Linked to original sources

PubMed1987

Neuronal protein biosynthesis by neonatally malnourished and nutritionally recovered rats.

1. The objective of the present study was to examine the reversibility of the effect of neonatal malnutrition on in vivo neuronal protein synthesis. 2. Neonatal malnutrition was achieved by letting the pups suckle mothers fed a low casein diet (6.4%) which decreased the amount of milk produced. The control group was composed of pups from mothers fed a 17% casein diet and kept on the same diet after weaning. A group of pups was undernourished during the suckling period, as above, but fed a 17% casein diet after weaning (recovered group). All animals were killed at 60 days of age. 3. Neuronal cell bodies were separated from forebrain by mechanical disruption of the tissue and centrifugation in a sucrose gradient. 4. Protein biosynthesis was measured by the incorporation of [14C]-leucine into proteins of neuronal cell bodies, after correcting for the specific activity of the precursor. 5. Forebrain cell number and cell size were evaluated by DNA content and the protein/DNA ratio, respectively. 6. The forebrains of the recovered group weighed less than those of the controls, perhaps due to a lower number of cells, which exhibited an average size similar to that of the control group. 7. The rate of protein biosynthesis was similar in malnourished and recovered groups, but both were only 57% of the rate of the control group. 8. We conclude that neonatal malnutrition promotes an irreversible adverse effect on in vivo neuronal protein synthesis by rats.

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↗

PubMed1965

EFFECT OF CAROB POD EXTRACT ON CELLULOLYSIS, PROTEOLYSIS, DEAMINATION, AND PROTEIN BIOSYNTHESIS IN AN ARTIFICIAL RUMEN.

Carob pod extract and its tannin and sugar fractions were compared with gallotannic acid and sucrose for their effect on the cellulolytic, proteolytic, protein biosynthetic, and deaminative activities of rumen microorganisms. The inhibitory effects of carob pod extract upon the cellulolysis and deamination were correlated mainly with its sugar, rather than its tannin components. On the other hand, proteolytic activity and protein biosynthesis were more significantly affected by the tannin fraction. In contrast to the tannin fraction of carob pod extract, gallotannic acid inhibited cellulolytic activity. The harmful effect of a low concentration of tannins on protein biosynthesis could be prevented by the addition of carbohydrates to the reaction mixture. At high tannin concentration (40 mug/ml), however, the addition of carbohydrates did not prevent the inhibition.

Ammonia↗

PubMed2007

Proteasome function and protein biosynthesis.

PURPOSE OF REVIEW: Protein synthesis and degradation govern protein turnover, which underlies the adaptation of organisms to changing developmental, physiological and environmental needs. The cellular mechanisms of these processes have been increasingly uncovered. Recent findings establishing additional links between protein synthesis and degradation are the topic of this review. RECENT FINDINGS: Several major developments in the field have taken place recently. First, the role of lysosomal-autophagosomal degradation, the established amino acid supplier for protein synthesis, has been demonstrated for additional diverse aspects of cellular physiology. Second, cytosolic protein degradation initiated by the proteasome has been assigned a critical role in sustaining ongoing protein synthesis upon acute nutrient restriction. A number of regulatory possibilities to modulate the intracellular amino acid flux by means of proteasomal degradation are discussed. Finally, the field of translation factor regulation by their degradation has emerged recently and is described here. SUMMARY: The elucidation of mechanisms determining protein turnover and, thus, cellular adaptation will help us to understand the (patho)physiological conditions caused or accompanying acute and chronic nutrient deficiencies and should lead to new therapeutic strategies to handle them.

Adaptation, Physiological↗

PubMedDate not supplied

[Modulating effect of surfactant on protein biosynthesis in lung macrophages].

Effect of lung surfactant on protein biosynthesis in macrophages at their cultivation in vitro has been studied. The surfactant is shown to stimulate protein synthesis in the cells. This phenomenon is probably stipulated by the increase of the transcription activity and formation of 45-pre rRNA, life of RNA. The surfactant is supposed to regulate the function of lung macrophages in norm and under pathology.

Animals↗

PubMed1996

Protein biosynthesis in low dose ionizing radiation-adapted human melanoma cells.

Adaptive responses induced by low dose gamma-ray irradiation in human melanoma cells were examined using a clonogenic assay. Survival fractions were significantly increased in cells irradiated with low dose gamma-rays then 4 hrs later with high dose gamma-ray as compared to cells irradiated only with high dose gamma-rays. When low dose irradiation was given 20 hrs prior to high dose irradiation, however, no adaptive response was induced. Changes in protein biosynthesis in human melanoma cells were observed under the same conditions. Significant changes in protein biosynthesis occurred in the nuclear and membrane proteins of cells first irradiated with a low dose then a high dose of gamma-rays after 4 hrs. No such changes were found in cells irradiated with low dose gamma-rays 20 hrs prior to high dose irradiation, consistent with the results of the clonogenic assay. Our findings suggest that prior treatment with low dose gamma-rays induces an adaptive response that has a significant effect on the induction of the nuclear and membrane protein biosynthesis caused by high dose gamma-ray irradiation of human melanoma cells.

Adaptation, Physiological↗

PubMed1987

20 (OH) ecdysone-induced transition from intermolt to premolt protein biosynthesis patterns in the hypodermis of the crayfish, Astacus leptodactylus, in vitro.

20 (OH) Ecdysone-induced alteration of protein biosynthesis and secretion by the hypodermis of the crayfish Astacus leptodactylus was studied using isolated tissues in vitro. Characteristic quantitative and qualitative changes of late intermolt tissues are governed by the hormone in a dose- and time-dependent manner. The greatest response to the hormone was observed in tissues which were exposed for 48 hr to 10(-8) M 20 (OH) ecdysone, followed by 1 day of hormone withdrawal. The observed differences correspond to the reprogramming in protein biosynthesis after transition from intermolt to the premolt stage.

Animals↗

PubMedDate not supplied

[Changes in the rate of protein biosynthesis in the organs of mice under the action of the delta sleep-inducing peptide and psychoemotional stress].

The effects of delta-sleep-inducing peptide (DSIP) and its analogs (ID-6 and ID-12) on the protein synthesis rate in the mouse brain, liver, and spleen were studied with special reference to mechanisms underlying the adaptogenic action of DSIP. Time-related changes of the protein synthesis rate were estimated in the mouse organs after a single intraperitoneal injection of the peptide (120 mg/kg body weight) and the psycho-emotional stress with or without preliminary (1 h before) injection of the peptide. After DSIP administration, the protein biosynthesis was activated and the dynamics of stress-induced changes of biosynthesis were modified. The data obtained suggest that the mechanisms underlying the DSIP adaptogenic action involve its modulatory effect on the regulatory system of protein biosynthesis.

Animals↗

PubMedDate not supplied

[Ethanol and protein biosynthesis in the animal liver (review of the literature)].

Protein biosynthesis was markedly altered in liver cells after acute and chronic administration of ethanol in vivo and in vitro. The effects were dose- and time-dependent. Synthesis of cytoplasmic and nuclear proteins was inhibited in hepatocytes. In chronic intoxication activity of fibroblasts and collagen synthesis were stimulated. The data obtained suggest that inhibition of amino acids activation, impairment of translation and transcription were involved in mechanisms of the ethanol toxic effects on liver tissue. At the same time, negative effects of ethanol and its metabolites appear to be related to post-translation modification of polypeptides.

Animals↗

PubMedDate not supplied

[Patterns of protein biosynthesis in the embryo and endosperm during embryogenesis in Pinus sylvestris L].

The patterns of protein biosynthesis in the embryo and endosperm during embryogenesis in the Scots pine were studied using electrophoresis and biochemistry methods. Proteins of the albumin-globulin fraction were visualized already at the early embryonic stages. The main polypeptide components (48-60, 37-39, and 20-22 kDa) were gradually accumulated in the course of maturation. A high synchrony was noted between the stages of embryogenesis and molecular events related to protein biosynthesis and accumulation in the developing seed.

Albumins↗

PubMed1974

Acetylation of reticulocyte ribosomal proteins at time of protein biosynthesis.

When rabbit reticulocytes were incubated in vitro with [(3)H]acetate, their ribosomal proteins were rapidly acetylated within 10 min. Polyacrylamide-urea gel electrophoresis showed that several major ribosomal protein fractions were highly acetylated. By the double-isotope labeling technique, the incorporation of [(3)H]acetate and [(14)C]aminoacid mixture into ribosomal proteins and nascent chains was found to be closely associated. Sodium fluoride abolished the acetylation of ribosomal proteins, whereas cycloheximide reduced the acetylation of ribosomal proteins to a much lower level. These findings suggest that acetylation of ribosomal proteins may be involved in the formation of the initiation complex during protein biosynthesis.

Acetates↗

PubMed1989

Effects of trypanocidal drugs on protein biosynthesis in vitro and in vivo by Trypanosoma cruzi.

Nifurtimox (NF) and benznidazole (BZ), drugs used in the treatment of Chagas' disease, did not inhibit protein biosynthesis in in vitro homologous cell-free systems isolated from Trypanosoma cruzi and Crithidia fasciculata; nevertheless, their addition to growing cultures caused polyribosomal depolymerization. On the other hand, Berenil, Antrycide and suramin, used against African trypanosomiasis, inhibited protein biosynthesis in vitro but did not affect ribosomal distribution, probably due to low permeability to the drugs. The results suggest that the inhibition by NF and BZ of protein synthesis, measured as [14C]leucine incorporation by other authors, is indirect, probably through inhibition of nucleic acid synthesis and energy metabolism.

Animals↗

PubMed1980

Protein biosynthesis in cultured human hair follicle cells.

A new technique has been used for culturing human keratinocytes. The cells grow on the basement membrane-like capsules of bovine lenses. Lens cells were removed from the capsules by rigid trypsinization. In order to exclude any contamination with remaining living cells the isolated capsules were irradiated with X-rays at a dose of 10,000 rad. In this way human epithelial cells can be brought in culture from individual hair follicles. Since feeder cells are not used in this culture technique, the biosynthesis of keratinocyte proteins can be studied in these cultures. 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 protein patterns identical to those of intact hair follicles. Product analysis of the urea-soluble fractions of microdissected hair follicles shows that the protein pattern of the cultured keratinocytes resembles the protein pattern of the hair follicle sheath. Studies on the metabolism of benzo(a)pyrene revealed that the enzyme aryl hydrocarbon hydroxylase (AHH) is present in cultured hair follicle cells. A possible use of our culture system for eventual detection of inherited predisposition for smoking-dependent lung cancer is discussed.

Animals↗

PubMed1953