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Biomedical subjects

M I Lerman

Publications and source records attributed to M I Lerman.

At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

[Cell-free system of protein synthesis from rat's cardiac muscle].

A cell-free system of protein synthesis from rat heart muscle is described. The system contained preparations of ribosomes, which were not separated from myofibrillar proteins. The conditions for incorporation of 14C-leucine into the polyribosomes of the fraction were established and its protein synthetizing activity was studied.

Animals↗
PubMedDate not supplied

[Metabolism of mRNA in regenerating mouse liver: acceleration of the processing and decay of mRNA].

The kinetics of accumulation of poly(A+)mRNA in polyribosomes and the ratio: poly(A+)mRNA/(poly A-)mRNA were studied in regenerating mouse liver. It has been found, that the ratio: (poly A+)mRNA/(poly A-)mRNA was associated with the function of the cells: (poly A+)mRNA fraction has been decreased to 7% at 7 hours after partial hepatectomy and then reached the original value (25%) at 30-40 hours. The kinetics of accumulation of (poly A+)mRNA in polyribosomes during the transition from resting to growing state has revealed that both the lifetime and the presumable time of processing of the mRNAs of free and membranebound polyribosomes were decreased as compared to resting liver cells.

Animals↗
PubMedDate not supplied

[Metabolic stability of the protein-synthesizing system of the myocardium in compensatory cardiac hyperfunction in actinomycin D block of RNA synthesis].

Under conditions of complete actinomycin block in rat heart muscle an inhibition of protein synthesis and dissociation of myocardial polyribosome structures were observed (half-life was equal to 6.5 hrs). In compensatory hyperfunction of heart muscle, caused by stenosis of aorta, the inhibitory effect of actinomycin D on the protein synthesis was manifested earlier than in control and was exhibited more distinctly. In myocardium under compensatory hyperfunction of heart muscle the protein synthesis was decreased by 50% within 4 hrs after administration of actinomycin into animals and it was completely inhibited within 10 hrs after the antibiotic administration. The alteration in stability of polyritobosomes under compensatory hyperfunction of heart muscle was specific for myocardium and was not observed in liver tissue.

Adaptation, Physiological↗
PubMedDate not supplied

[Determination of the time of polypeptide chain synthesis in animal experiments].

A method is worked out for the estimation of the time of polypeptide chain synthesis in animals in vivo. The time of the synthesis of "middle" polypeptide was found to be 1.45 min. in mouse liver cells under normal conditions, while in the presence of translation inhibitors, cycloheximide (20 mg/kg) and aurintricarboxilic acid (1 g/mg) the time of the synthesis increased in 2.7 and 2.5 times respectively. The time of polypeptide synthesis linearly increased with the increase of aurintricarboxilic acid dose.

Animals↗
PubMedDate not supplied

[Kinetics of the in vivo synthesis of the polypeptide chain; the effect of translation inhibitors].

Effects of aurinetricarbonic acid and cycloheximide on kinetics of polypeptide chain synthesis and polyribosome protile in mouse liver cell in vivo are studied. Both compounds are found to decrease the absolute rate of protein synthesis and to increase the time of polypeptide synthesis. Cycloheximide changed the ratio of translating and non-translating ribosomes and different in size polyribosome types. Aurinetricarbonic acid exerts no effect on polyribosome profile. Effects of cycloheximide and aurinetricarbonic acid on kinetic parameters of translation and a mechanism of action of these compounds are studied.

Animals↗
PubMedDate not supplied

[The interaction between newly-formed mRNA and ribosomal particles during retarded translation].

The formation of polyribosomes in mouse liver cells at the reduced-rate translation was studied by treatment with cycloheximide (CHI) and aurintricarboxylic (ATA) acid. An increase of polypeptide synthesis time by 1.7-2.7 times (0.5 mg CHI per 25 g of weight or 15 mg ATA per 25 g) leads to a delay of the entrance of newly formed cytoplasmic D-RNA into polyribosomes. These results are in agreement with the model of polyribosome formation from ribonucleoprotein precursors containing cytoplasmic D-RNA. On the other hand, in the presence of a CHI dose (5 mg/25 g) causing a dramatic (240-fold) increase of polypeptide synthesis time, the kinetics of entrance of newly formed D-RNA into polyribosomes does not differ from the normal one, and amount of the incorporated mRNA is even somewhat higher than under normal conditions. It is suggested that in this situation ribosomes are moving along the newly formed mRNA, and their movement is not accompanied by the synthesis of completed polypeptide chain.

Animals↗
PubMedDate not supplied

[RNA and protein metabolism in the myocardium in aging and long-term hyperfunction of the heart].

Metabolism RNA and proteins was distinctly altered in myocardium hypertrophied due to prolonged hyperfunction and in the heart muscle of aged rats. The following alterations were observed: decrease in RNA concentration and in the absolute rate of protein synthesis in vivo, decrease in incorporation of labelled amino acids into heart ribosomes in cell-free system, the distinct depression of RNA turnover. The data obtained suggest that prolonged heart hyperfunction and hypertrophy promote the myocardium impairment and hence the process of senescence in developed more rapidly than under normal conditions.

Aging↗