[The use of nontraditional approaches to the analysis of the effects of radiation on the system of protein phosphorylation in spleen lymphocytes]. / Ispol'zovanie netraditsionnykh podkhodov dlia analiza vliianiia oblucheniia na osobennosti funktsionirovaniia sistem fosforilirovaniia belkov v limfotsitakh selezenki]

Postradiation disturbances in functioning of Ca(2+)- and cyclic nucleotide-dependent protein kinase systems are established. Kinetic index of different protein kinases of spleen lymphocytes under irradiation with doses of 0.5 and 1 Gy are analysed using return-cards-construction and Lyapunov's-coefficient-determination methods. It is shown that determined disturbances can be considered as a part of general unspecific adaptational reaction of lymphocytes to irradiation.

[Effect of x-irradiation on the properties of cyclic AMP-dependent protein kinases from rat spleen lymphocytes]. / Vliianie rentgenovskogo oblucheniia na svoistva tsAMF-zavisimykh proteinkinaz iz limfotsitov selezenki krys.

It was shown, that in conditions of acute radiation affection in doze 0.5 and 1 Gy, there was a decrease of 32 and 55% in activity of cyclic AMP-dependent protein kinases, isolated from cytosol of lymphocytes. The analysis of cAMP-dependent protein kinases properties has shown, that disturbance in the interaction of the enzyme with protein substrate of phosphotransferase reaction and main modulater enzymes activity--cAMP proceeds of the ionising radiation effect.

[Effect of ionizing radiation on the structure and functional properties of the basolateral membrane of small intestine enterocytes]. / Vliianie ioniziruiushchei radiatsii na strukturu i funktsional'nye svoistva bazolateral'noi membrany énterotsitov tonkogo kishechnika.

The structural state and transport properties of basolateral membrane of rat small intestine enterocytes after exposure to X-ray irradiation (0.5; 1.0 and 2.0 Gy) were studied. The substantional suppression of the active Ca(2+)-transport process concomitant to versatile changes of the membrane structure involving the surface sites and intramembrane protein-lipid complexes was revealed one day after irradiation. Taking into account the early obtained data on apical membrane functional disorders these results confirm that ionizing radiation in sublethal doses induces the structure-function modification of enterocyte plasma membrane affecting the function of the small intestine epithelial cells.

[Electric activity of fragmented sarcoplasmic reticulum associated with the organic phase-water interface]. / Issledovanie élektricheskoi aktivnosti fragmentirovannogo sarkoplazmaticheskogo retikuluma, assotsiirovannogo s granitsei razdela organicheskaia faza-voda.

Electric activity of fragmented sarcoplasmic reticulum (FSR) in the model system organic phase-water was investigated by dynamic capacity method. FSR induced Mg-ATP, Ca2+-dependent change of border volt-potential only when phospholipids were present in the organic phase. It is suggested that FSR electric activity at the interface lipid-water is conditioned by functioning Ca2+, Mg2+-ATPase.

[The role of membrane phosphoinositides in mediating hormonal effects]. / Rol' membrannykh fosfoinozitidov v oposredovanii gormonal'nykh éffektov.

The present notions on the pathways of phosphoinositide metabolism in a cell and on the functional significance of the given process are reported. The enzymic systems providing catabolism of phosphoinositides are analyzed. The data indicating the dose interrelation between the stimulation of the phosphatidyl inosite and polyphosphoinositides metabolism by hormones and the Ca2+ transport into a cell are generalized. Universality, biochemical mechanisms and functional significance of the "phosphatidyl inosite" response are discussed. The phosphoinositide metabolism is considered from the standpoint of its significance for other cell processes: synthesis of eicosanoids, provision of Ca2+-dependent processes in the synapse, cell proliferation, activation and the "anchoring" of enzymes on membranes.

[High molecular weight multienzyme complexes of aminoacyl-tRNA-synthetases in eukaryotic cells]. / Vysokomolekuliarnye mul'tifermentnye kompleksy aminoatsil-tRNK-sintetaz v kletkakh éukariot.

The data available in literature on the possibility of the aminoacyl-tRNA-synthetases to function in different eukaryote cells in the composition of high-molecular-weight complexes are generalized. Interactions in complexes formed by synthetases and other components as well as the physiological significance of such universal multi-enzymic complexes in cells of higher organisms are discussed.

[Release of arachidonate from rat spleen lymphocytes after irradiation]. / Vysvobozhdenie arakhidonata iz limfotsitov selezenki krys posle oblucheniia.

After spleen lymphocytes incubation with 14C-arachidonic acid 14C label was found associated predominantly with phosphatidylethanolamine (PE) and phosphatidylcholine (PC). Addition of 0.5 mkM a 23187 to the incubation media with 2 mM CaCl2 caused a 4-fold increase in release of labeled free arachidonate in lymphocytes of the control animals. A dose-dependent increase in release of free arachidonate and membrane Ca(2+)-dependent phospholipase activity towards exogenous 2-14C-arachidonoyl-PE and -PC take place in a period 6-12 h after animal's irradiation in a doses 0.5 and 1.0 Gy. The maximum arachidonate release in 6h following 1 Gy irradiation correlates with activation of more active phospholipase A2, hydrolyzing PE. Free arachidonate is supposed to be mobilized from different phospholipid pools, depending on the content of Ca2+ in the cells after irradiation.

[Structural changes in the sarcoplasmic reticulum membrane of skeletal muscles at the early stage of x-ray irradiation]. / Strukturnye izmeneniia membran sarkoplazmaticheskogo retikuluma skeletnykh myshts na rannem étape rentgenovskogo oblucheniia.

A single X-ray irradiation of the rabbit hindlimbs in a dose of 0.24 C/kg evokes a decrease in fluorescence of the ANS probe bound with membranes of the sarcoplasmatic reticulum as a result of the decrease of binding sites, binding constant as well as the quantum output of the probe. A decrease in fluorescence of tryptophan residues of Ca-ATPase localized in membranes and attenuation of interaction of its SH-group with dithionitrobenzoic acid has been also observed at early postradiation terms (1 and 24 h). The obtained results evidence for structural rearrangements occurring in membranes of the sarcoplasmic reticulum under the effect of ionizing radiation. Changes in conformation of CA-ATPase molecules contribute much to this process.

[Properties of cyclic nucleotide phosphodiesterase from plasma membranes of rat synaptosomes at early stages of acute radiation injury]. / Svoistva fosfodiésterazy tsiklicheskikh nukleotidov plazmaticheskikhmembran sinaptosom golovnogo mozga krys na rannikh étapakh ostrogo luchevogo vozdeistviia.

Phosphodiesterase of cyclic nucleotides from membranes of rat brain synaptosomes hydrolyzes cAMP and cGMP; the maximal rate of cAMP hydrolysis is 2.5 times higher than the values of the analogous index for GMP. The enzyme is found to be activated by calmodulin. A different direction of changes in the rate of cAMP and cGMP hydrolysis is observed 1 h after total X-ray irradiation. The process of cAMP hydrolysis by phosphodiesterase is characterized by positive cooperativity which is also shown after irradiation and for the process of cGMP hydrolysis. It is established that enzyme inhibition by the reaction product takes place both in control and after irradiation.

[Properties of phosphoprotein phosphatase from the rat liver]. / Svoistva fosfoproteidfosfatazy iz pecheni krys.

Prosphoproteid phosphatase, an enzyme highly specific to lysyl-tRNA-synthetase and proteins of the high-molecular-multienzymic complex of aminoacyl-tRNA-synthetases, was isolated from the rat liver. The data of electrophoresis in 4-30% PAAG with the presence of DS-Na have shown that phosphoproteid phosphatase is homogeneous and its molecular mass is 56 kDa. The isolated phosphoproteid phosphatase is activated by 2.5 mM Mg2+, Mn2+ and is inhibited by ions of univalent metals ions--200 mM Na+, 5 mM K+ as well as by 1 mM ATP, ADP, AMP.

[Study of conditions of association of liposomes modified by Ca2+-ATPase in the organic phase-water system]. / Izuchenie uslovii assotsiatsii liposom, modifitsirovannykh Ca2+-ATP-azoi, v sisteme organicheskaia faza-voda.

Conditions are experimentally found for association of liposomes formed of asolectine and Ca2+-ATPase of sarcoplasmic reticulum with interface "asolectine solution in decane--water". It is established that Ca2+ ions participate in the change of Mg-ATP-dependent interface potential in this model system.

[cGMP-dependent protein kinases: properties, regulation and biological role]. / cGMP-zavisimye proteinkinazy: svoistva, reguliatsiia i biologicheskaia rol'.

The data available in literature on properties, methods of regulation and biological role of cGMP-dependent protein kinases are analyzed and generalized. Evidence on distribution of these enzymes in different tissues and intracellular compartments is presented. Physicochemical properties of cGMP-dependent protein kinases from different sources are analyzed. Peculiarities of their primary structure, regulation of their activity at the expense of autophosphorylation as well as in the presence of the modulator protein, metal ions and other factors are considered. These data permit postulating importance of cGMP-dependent phosphorylation in some physiological and biochemical processes.

[Phospholipase A2 from rat spleen lymphocytes hydrolyzing arachidonoyl-phospholipids]. / Fosfolipaza A2 limfotsitov selezenki krys, gidrolizuiushchaia arakhidonoil-fosfolipidy.

Phospholipase A2 activity in the postnuclear supernatant of lymphocytes has been studied by measuring 14C arachidonate released from labelled phosphatidyl ethanolamine (PE) and phosphatidyl choline (PC) as exogenous substrates. The pH optimum was 7.5-9.0 for PE and 9.0 for PC. Phospholipase A2 was not detected in the presence of 2 mM EGTA. It was optimal with the millimolar calcium concentrations and higher towards PE. Preincubation of lymphocytes with 0.5 M ionophore A-23187 was followed by 2.4 fold stimulation of the phospholipase activity. A stimulatory effect was observed after preincubation of cells with 10 micrograms/ml of phytohemagglutinin, lipopolysaccharide, concanavalin A; it decreased as: lipopolysaccharide greater than phytohemagglutinin greater than concanavalin A. The results obtained have suggested the possibility of existence of different forms of phospholipase A2 in the spleen lymphocytes and participation of the enzyme in the early signalling events.

[Physico-chemical properties of lysyl-tRNA-synthetase from the rat liver]. / Fiziko-khimicheskie svoistva lizil-tRNK-sintetazy pecheni krys.

Two lysyl-tRNA-synthetase forms are obtained from the rat liver. Their molecular masses are determined by electrophoresis and gel-filtration on Sephadex G-150: form I-122, form II-64 kDalton. Gel-electrophoresis in the presence of 0.1% SDS indicates that form I of lysyl-tRNA-synthetase consists of two subunits with a molecular mass of 64 kDalton each, i. e. it is a dimer. Optimal conditions and kinetic parameters (Km and Vmax) of aminoacylation for the both enzyme forms are similar. Amino acid composition, fluorescence parameters and thermal inactivation conditions are determined.

[Metabolism of choline-containing phospholipids in microsome fractions of the rat brain in acute radiation injury]. / Obmen kholinsoderzhashchikh fosfolipidov fraktsii mikrosom golovnogo mozga krys v usloviiakh ostrogo luchevogo porazheniia.

A considerable increase in activation of CDP-dependent pathway of the phosphatidylcholine and sphingomyelin synthesis in the microsomal fraction of rat brain grey matter is established one hour after the acute radiation injury. The level of [14C] choline incorporation into phosphatidyl choline is twice as low under these conditions.

[Second messenger systems and protein kinase activity in rat thymus and liver in the early stages of radiation injury]. / Sistemy vtorichnykh messendzherov i aktivnost' proteinkinaz v timuse i pecheni krys na rannikh étapakh luchevogo porazheniia.

The effect of ionizing radiation (7, 76 Gr) on the content of cyclic nucleotides and Ca2+ ions from rat thymus and liver has been established: it was increased 15, 30 min and 4.6 h and decreased 2, 12 h and 24 h after the irradiation. Changes in activity of cyclic nucleotide-dependent protein kinases and Ca2+, phospholipid-dependent protein kinase correlated with the contents of secondary messengers in the irradiated rats (30 min and 4 h after irradiation) are shown.

[Lipid peroxidation of rat spleen and thymus lymphocytes treated with x-rays (0-5-1.0 Gy)]. / Perekisnoe okislenie lipidov limfotsitov selezenki i timotsitov krys pri vozdeistvii rentgenovskogo oblucheniia (0.5-1.0 Gr).

It is established, that low doses of X-ray irradiation have affected activation of lipid peroxidation (LPO) in immunocompetent cells of the spleen and thymus. The amount of malonic dialdehyde (MDA) in lymphocytes of spleen and thymocytes increases 2 times twenty-four hours after animals' irradiation by X-rays in a dose of 0.5 Gy; when a dose grows to 1.0 Gy, the MDA content in the spleen lymphocytes increases from the 1st to the 6th days and in thymocytes from the 1st to the 3d days reaching its maximum at the 3d day. MDA accumulation in the immunocompetent cells of irradiated animals varies depending on the method of lipid peroxidation initiation.

[Study of the effect of phosphorylation of histones on their interaction with DNA-cellulose]. / Issledovanie vliianiia fosforilirovaniia gistonov na ikh vzaimodeistvie s DNK-tselliulozoi.

Data about the influence of phosphorylation levels of histones isolated from the prereplicative and replicative phases induced to proliferation by cycloheximide of rat hepatocytes, on their interaction with DNA-cellulose are presented. It is shown that the DNA-cellulose chromatography of histones is a sensitive model for the investigation of the effect of phosphorylation of histones on their electrostatic interaction with DNA. Using this method it is possible to separate high-phosphorylated subtype of rat liver H1 histones from other subtypes and also to show a direct dependence between the phosphorylation levels of histones and stability of their binding with DNA in prereplicative and replicative phases not only under conditions of proliferation induction by cycloheximide, but also under the subsequent influence of X-irradiation and serotonin.

[Effect of quaterin and S-methylmethionine on the intensity of chromatin protein methylation]. / Vliianie kvaterina i S-metilmetionina na intensivnost' metilirovaniia belkov khromatina.

It is known that 3-(2,2,2-trimethylhydrazinium) propionate (quaterin) synthetized at the Institute of Organic Synthesis of the Latvian SSR Academy of Sciences has a stimulating effect on cell proliferation in the process of healing wounds and burns. In this connection the above preparation is studied for its effect on the methylation intensity of histones and nonhistone proteins of rat tissues possessing different proliferative activity. For comparison S-methylmethionine (vitamin U), a known stimulator of the methylation reactions, was studied. The experiments conducted have shown that the methylation processes in all the studied tissues (heart, liver, small intestine mucosa, thymus and spleen) depend on the quaterin and the S-methylmethionine effect. On the whole, quaterin 1-6 h after its administration increases, as a rule, the methylation levels of histones and nonhistone proteins. This effect is the least in the thymus and the highest in the liver and spleen. When quaterin is applied daily for 5-15 days considerable changes occur in the levels of chromatin proteins methylation. The data obtained indicate that the processes of chromatin proteins methylation are an important link in the realization of quaterin action on transcription and replication which underlie the proliferative cell response.

[Stimulation with quaterin of DNA replication and repair]. / Stimuliatsiia kvaterinom intensivnosti replikativnogo i reparativnogo sinteza DNK.

Quaterine [3-(2,2,3-trimethylhydrasinium)propionate] possessing a wide spectrum of physiological activity has been studied for its effect on the intensity of replicative and reparative DNA synthesis in different rat tissues (liver, thymus, heart, intestine mucosa and spleen) in order to investigate molecular mechanisms of its action. It is shown that the pronounced stimulation of DNA synthesis in all tissues, as a rule, takes place 1-6h after quaterine administration in doses of 25 and 100 mg/kg. The estimation of the given compound effect on DNA synthesis after its multiple administration to animals (for 5, 10, 15 days in a dose of 100 mg/kg) permits supposing that 3-(2,2,2-trimethylhydrasinium)propionate is able of providing either stable proliferation of cells (thymus, spleen) or their hyperplasia and polyploidization (heart, liver). The data obtained make it possible to explain (to some extent) quaterine ability to activate immune responses, to stimulate healing of wounds and burns.