Ukrains'kyi biokhimichnyi zhurnal最新文献

Biosynthesis of cholesterol and its precursors (metastenol, latosterol and 7-dehydrocholesterol) was studied in the mucous and serous membranes of small intestine, secretory and esophageal regions of the normal rat stomach. The content of these sterols was also determined. The intensity of sodium 2-14C-acetate incorporation into cholesterol and its precursors in the mucous membrane of the small intestine and stomach secretory region is considerably higher than into the same sterols of the serous membrane and esophageal region. Cholesterol synthesis is most intensive in the small intestine mucous membrane and stomach secretory region.

The interaction was studied between two fragments of bovine fibrinogen isolated from its tryptic hydrolysate: the D fragment, an inhibitor of fibrin-monomer polymerization, and the protector, a fragment inactivating the D fragment. This reaction is relatively rapid: it is completed for several minutes at room temperature and at 37 degrees and is slowed down at 5 degrees. However, the reached level of the D fragment inactivation does not depend upon temperature (within a range from 5 degrees to 37 degrees). Dilution of the incubation mixture under applied conditions caused no dissociation of the D fragment-protector complex. Inactivation of the D fragment by the protector depends on the solution ionic strength; ionic strength 0.13-0.16 is optimal.

Experiments on rats established that tRNA of the liver under the effect of total X-irradiation (800 R), nicotinic acid and neostigmine methylsulphate proves to be hypermethylated. In this case tRNA molecules undergo conformation changes. Nicotinic acid and neostigmine methylsulphate administered to the animals under experiment an hour before irradiation favour the normalization of these indexes. As a rule, a correlation is observed between changes in methylation of tRNA and activity of their methylases. Irradiation inhibits the processes of tRNA synthesis which are normalized under the effect of nicotinic acid administered before the irradiation. Nicotinic acid and neostigmine methylsulphate produce no effect on synthesis of tRNA in the liver of normal animals. The activity of acid tRNase under the effect of nicotinic acid is not changed, under other conditions of the experiment it decreases. Irradiation against a background of nicotinic acid and neostigmine methylsulphate administered to animals and neostigmine methylsulphate administration to the intact animals inhibit the activity of alkaline tRNase.

A procedure is proposed for electrophoretic studies of skeletal and smooth muscle myosins in 2.2% polyacrylamide gel at high ionic strength (mu = 0.4). When separated by electrophoresis myosin is shown to retain the ATPase activity which was dtermined histochemically directly in the gels. It is established that myosin molecules of the studied types of muscles have different electrophoretic mobility. At the electrophoresis on dodecylsulphate gels two types of light chains were detected in the smooth muscle myosin (their molecular weights being 26,900 and 17,800) in contrast to skeletal myosin which has three types of light chains. The obtained data evidence for existence of isoenzymic forms for myosin.

The specific activity of markers-enzymes in the subcellular fractions of the rabbit visual analyzer cortical end, the synaptosomes and mitochondria of nerve cells, changed under the effect of early long deprivation. For cytochromoxidase and Na+, K+-ATPase it lowers considerably in all subfractions, for monoaminoxidase and Mg2+-ATPase it rises mainly in synaptosomes; the activity of acetyl cholinesterase lowers per 1 g of tissue. In the light two weeks later a tendency is observed to normalization of the studied indexes. The specific activity of cytochrome oxidase (except for free mitochondria) and Na+, K+-ATPase reaches the control, that of monoaminoxidase also partially normalizes, but not competely; Mg2+ATPase in all the subfractions is more inhibited than in the control. This evidences for the effect of light deprivation on the activity of the enzymes associated with different cycles of metabolic processes, first of all, of oxidation and ion transport. These changes are reversible when visual impulsation is recovered. Disturbances in chemism at the subcellular level are specific for different enzymic systems and are not the same in certain subfractions of great hemispheres.

The content of nucleic acids in tissues of healthy animals and those suffering from thyrotoxicosis was studied as affected by parenteral administration of amino acid mixture of moriamine S-2 and casein hydrolysate. The content of RNA in the skeletal muscles, heart and liver is established to change considerably under the effect of nitrogenous media. With administration of moriamine S-2 or caseine hydrolysate the higher level of RNA in tissues with thyrotoxicosis, is normalized, especially in the skeletal muscles. The character of changes depends essentially on properties and composition of the administered preparations.

Experimental hypercorticism induced by multiple injections of ACTH-zinc-phosphate inhibits the incorporation of 1-14C-alanine and 3H-methionine into proteins of the liver, spleen, musculus quadratus femoris, blood and nuclear plasma, mitochondria, microsomas and cytosol of the liver as well as decreases the protein content in them. Under the effect of ACTH-zinc-phosphate in combination with enteral administration of sodium ribonucleate, the deviations from the normal level in the incorporation of the labelled amino acids into proteins and in the protein content of the tissues under study are less pronounced than under the effect of the hormone only. An opinion is advanced that enteral injection of sodium ribonucleate may be more preferable than parenteral administration of this preparation with hypercorticism under clinical conditions.

A protein fraction was isolated from the TCA residue of beef brain water-soluble proteins by 80% ethanol treatment. This fraction accounts for 3% of the total brain protein. The heterogeneity and tissue specificity of its component are studied by electrophoreses in 10% polyacrylamide gel (pH 8.3). The fraction consists of three proteins with different electrophoretic mobility and tissue specificity.

The rate of oxidative phosphorylation was studied in heart mitochondria of rats which were administered hydrocortisone and then corticoid in combination with insulin. It is established that 5 h after a single administration of hydrocortisone oxidative phosphorylation increases slightly and is statistically insignificant. Injections of corticosteroids to animals for 14 days inhibit considerably the rate of oxidation and phosphorylation, cause a decrease in the values of respiratory control and APD/O coefficient. Administration of insulin simultaneously with hydrocortisone to animals normalizes these disturbances to a considerable extent.

Medicamental stimulation has a definite positive effect on metabolism of macroergic compounds in the muscles of the replanted and contralateral extremeties. Application of medicamental stimulation reduced the time for the muscle reparation, increased considerably the level of creatine-phosphoric acid and ATP both in the replanted and intact extremeties as well as restored the succinate dehydrogenase activity. 4-Methyluracil applied in combination with vitamins proved to be the most effective preparation under conditions of the experiment.