[The enzymatic activity of the antioxidant system in the ontogeny of mutant norflurazone-tolerant Arabidopsis thaliana]. / Izuchenie aktivnosti fermentov antioksidantnoi sistemy v ontogeneze mutantov Arabinopsis thaliana, tolerantnykh k norflurazonu.

The activities of superoxide dismutase and guaiacol-dependent peroxidase were studied in the ontogenesis of recessive homozygous mutants of Arabidopsis thaliana Heynh. le-2 and nfz24, which are characterized by two- to threefold increases in tolerance to the herbicide norflurazone. The mutants le-2 and nfz24 differed from the initial race Dijon in some phenotypic features, duration of ontogenetic stages, and dynamics of the superoxide dismutase and peroxidase activities in ontogenesis. A single treatment of plants with norflurazone induced an accelerated increase in the level of both enzymes in the mutants as compared to the wild type plants. Under the conditions of multiple treatment with norflurazone, the mutants le-2 and nfz24 displayed a higher tolerance to the bleaching effect of the herbicide and were characterized by a higher level of superoxide dismutase. The data obtained suggest that the superoxide dismutase and peroxidase activities are controlled by both ontogenetic factors and stress signals. Mutations in the lines le-2 and nfz24 increase sensitivity to a stress signal or increase efficiency of an adaptive response due to long-term maintenance of a high level of the antioxidant enzymes under the conditions of stress.

[Dependence of the process leading to phosphorylation of retinoblastoma protein (pRb) on the status of the actin cytoskeleton]. / Zavisimost' protsessa, vedushchego k fosforilirovaniiu belka retinoblastomy (pRb), ot sostaiianiia aktinovogo tsitoskeleta.

It has been confirmed that the main actin-dependent period of G1 phase of the cell cycle is the middle of G1. As the critical points in G1 phase are associated with the synthesis of cycling D and E and with the formation of their active complexes with cyclin-dependent kinases (Cdk's), a study of a possible influence of actin filaments on these processes was performed. The activity of G1 kinases was estimated by the degree of phosphorylation of their specific substrate-retinoblastoma protein (pRb). Immunoblot analysis with specific antibodies to pRb revealed hypophosphorylated from of Rb in lysates of resting Swiss 3T3 cells and the appearance of hyperphosphorylated form after 12 h of EGF and serum stimulation. In was shown that actin filaments distruction by H2CB led to a decrease in hyper phosphorylated form appearance, depending on the depth of resting state of the cells and efficiency of their stimulation by growth factors. Thus, these data may suggest the involvement of actin cytoskeleton in functioning of the transcription chain cyclin/Cdk-R1-E2F.

[The microorganism count on impression materials following disinfection by dynamic plasma treatment]. / Soderzhanie mikroorganizmov na slepochnykh massakh posle dezinfektsii metodom dinamicheskoi plazmennoi obrabotki.

B. subtilis and B. cereus in concentrations under 10(5) mt, and of E. coli M-17 below 10(7) mt on different plaster materials die within fractures of a second after dynamic plasma processing at atmospheric pressure and at least one passing of the processed surface at a rate of 2.0 to 2.5 m/s at plasma flow power of 60 kw.

[The ligand-dependent phosphorylation of epidermal growth factor receptors and the production of a secreted form of the receptor by cell strains of A-431 epidermoid carcinoma]. / Ligandzavisimoe fosforilirovanie retseptorov épidermal'nogo faktora rosta i produktsiia sekretiruemoi formy retseptora kletochnymi shtammami épidermoidnoi kartsinomy A-431.

Primary reactions on the addition of the epidermal growth factor (EGF) were investigated for the strains of A-431 cells, resistant to the antiproliferative effect of EGF. In spite of differences of EGF reception in the obtained strains, the EGF receptors in membrane preparations of these strains maintain the phosphorylating ability after addition of EGF. The rate of internalization of 125I-EGF in normal and resistant cells is the same. The production of a secreted fragment of the EGF receptor in resistant cells is lower than in normal ones. Questions of regulation of production of the normal receptor and of its shortened secreted fragment are discussed.

[Effect of amines on insulin-stimulated processes: the transport of sugars and synthesis of glycogen in frog sartorius muscles]. / Vliianie aminov na insulinstimuliruemye protsessy: transport sakharov i sintez glikogena v portniazhnykh myshtsakh liagushki.

Amines and amides were found to inhibit the process of stimulation of sugar transport in muscle tissue (N. A. Vinogradova et al., 1978). The present paper reports results of experiments on frog sartorius muscles acted upon by amines and other substances that inhibit induction of cultured cell proliferation. The stimulation of sugar transport induced by insulin, 2,4-dinitrophenol, or KCl was found to be inhibited by dansylcadaverine (1 mM), 5-methoxytryptamine (2 mM), or methylamine (100 mM). Such substances as chloroquine, bacitracin, or monensin exerted no effect. Besides, dansylcadaverine (1 mM), and 5-methoxytryptamine inhibited the stimulation of insulin induced glycogen synthesis. Dansylcadaverine was ineffective at concentrations lower than 0.5 mM. It is suggested that the inhibitory action of amines depends on their influence on the processes of membrane protein phosphorylation.

[Entry of cyclic nucleotides into frog muscles in vivo and in vitro]. / Postuplenie tsiklicheskikh nukleotidov v myshtsy liagushki v usloviiakh in vivo i in vitro.

The radioactive isotopes of cyclic nucleotides were used to study the possibility of their income to the isolated frog muscle from the environment as well as their distribution between blood plasma and muscle after injection to an animal. It is shown that the intracellular levels of nucleotides may be considerably higher after soaking the isolated muscle in 10(-6) M cGMP or 10(-4) cAMP solutions. After the cAMP injection into the lymphatic sac its content in blood and especially in muscles is high for a long time. In this case the label loss in muscles proceeds slower than in blood. A conclusion is drawn that conduction of studies on the artificial increase of the intracellular level of cyclic nucleotides by means of their injection to an animal is appropriate.

[Effect of dansylcadaverine on the epidermal growth factor-stimulated phosphorylation of uridine]. / Vliianie dansilkadaverina na stimulirovannoe épidermal'nym faktorom rosta fosforilirovanie uridina.

The increase of uridine phosphorylation during the first hour after epidermal growth factor (EGF) stimulation (1.25 nM) of Swiss 3T3 cells is completely blocked by 100 microM dansylcadaverine (DC). Lack of the effect of DC on uridine transport, uridine kinase activity in cell homogenate, intracellular ATP concentration and plasma membrane permeability for phosphorylated uridine derivatives makes it possible to propose the inhibition by DC (100 microM) of the activated state of uridine kinase. The rapidity of the inhibition of EGF effect and the lack of influence of DC (in tested concentration) upon the clustering of EGF-receptor complexes, rate of their internalization (Sorkin, 1985; Nikol'skii et al., 1987) and pH value of intracellular compartments (Sorkin et al., 1985; Teslenko et al., 1986) may suggest an association of DC inhibitory action with blocking of some steps of the receptor mediated endocytosis. Accumulation of DC in cell membranes, rather than in intracellular compartments with acidic pH, is a necessary factor for its blocking effect. Possibilities of DC action through the influence on calmodulin-dependent proteins or EGF-induced cell protein phosphorylation are discussed.

[Uptake of cyclic adenosine-3,5-monophosphate by cultured mammalian cells and frog muscles]. / Postuplenie tsiklicheskogo adenozin-3,5-monofosfata v kul'tiviruemye keltki mlekopitaiushchikh i myshtsy liagushki.

Uptake of 3H-cAMP by isolated frog sartorii muscles and cultured mouse 3T3 and 3T6 cells was studied. It was shown that after 1-2 hours of incubation the intracellular level of cAMP in frog muscles reached 10-20% of its concentration in the incubation medium. About 50% of intracellular radioactivity was represented by chromatographically pure cAMP which testifies to the insignificant cAMP metabolism rate. In the experiments with 3T3 and 3T6 cells the influence of possible admixtures and degradation products on 3H-cAMP uptake was revealed. To avoid these influences it is necessary to measure the uptake of cAMP in the presence of theophylline and with abundance of adenosine. In such experimental conditions the intracellular level of cAMP after 1 hour of incubation did not exceed 10% of its extracellular level, which is similar to values obtained on frog muscles. Permeability coefficient of cAMP for membrane of frog muscles and 3T3 and 3T6 cells was about 10(-9)-10(-8) cm X sec-1.

[Uptake of cyclic guanosine-3',5'-monophosphate and its metabolism in 3T6 cells]. / Postuplenie tsiklicheskogo guanozin-3',5'-monofosfata i ego metabolizm v kletkakh 3T6.

Uptake of 3H-cGMP by cultured murine 3T6 cells was studied. The cells were shown to contain radioactivity 1 minute after its addition, with the level of radioactivity increasing during a 3 hour incubation period. By this time, the intracellular non-metabolized cGMP corresponded to 1-5% of the whole intracellular radioactivity. In the presence of theophylline the uptake of 3H-cGMP by cells was seen decreasing, however, the portion of non-metabolized cGMP reached 45-50% of the whole intracellular radioactivity. Thus, the presence of theophylline made it possible to maintain the high level of intracellular cGMP. It is concluded that the incubation of cell cultures in the medium with cGMP may be useful for achieving an elevating intracellular cGMP concentration and for studying the biological effect of cyclic nucleotide.

[Role of calcium ions and cyclic nucleotides in neurotrophic control of the membrane properties of muscle fibers in the frog]. / Rol' ionov kal'tsiia i tsiklicheskikh nukleotidov v neirotroficheskom kontrole svoistv membrany myshechnykh volokon liagushki.

Subcutaneous injections of caffeine, calcium ionophore X537A or cAMP did not affect the changes of input resistance (R0) and time constant (T) of membrane caused by denervation of the frog m. sartorius but prevented the MP decrease and ACh sensitivity spread. Injections of cGMP did not affect the denervation changes of R0 and MP but increased the ACh sensitivity. The neurotrophic control of frog muscle membrane properties seems to depend on calcium and involve the cyclic nucleotides system.

[3',5'-AMP content of the bone marrow in mice during radiation and thermal injury]. / Soderzhanie 3',5'-AMP v kostnom mozge myshei pri radiatsionno-termicheskoi travme.

An elevated level of cAMP as compared to the control was observed in the bone marrow of mice 2 and 20 h after radiation-thermal trauma. No potentiation of burn and radiation effects was noted. It is assumed that thermal factor causes a delay of proliferating cells at the cycle stage where the level of this nucleotide achieves its maximum value without any influence.

[Independence of the insulin effect from the guanosine-3',5'-monophosphate level in muscle tissue]. / Nezavisimost' éffekta insulina v myshechnoi tkani ot urovnia guanozin-3',5'-monofosfata.

The role of cyclic GMP in the insulin effect was investigated using isolated frog sartorii. A study was made of the effect of exogenous cyclic GMP, dibutyryl cyclic GMP, 8-bromo-cyclic GMP on xylose transport, glycogen synthesis and muscle respiration. Only dibutyryl cyclic GMP (1.10(-6) - 10(-4) M) alone was observed to have a stimulating effect on glycogen synthesis and respiration. The xylose transport was but slightly accelerated only following a 20 hours incubation of muscles in the cyclic GMP solution. Cyclic GMP was shown to penetrate the muscle fibres. The cyclic GMP content in muscles was equal to 22.7 +/- 2.0 pM per gram of wet weight. Insulin exerted no effect on cyclic GMP concentration in muscles. The data obtained do not allow to conclude that cyclic GMP may serve as a mediator in realization of the insulin effect on membrane and intracellular processes.

[Effect of insulin and adrenaline on the respiration and glycolysis of the skeletal muscle of frog]. / Vliianie insulina i adrenalina na dykhanie i glikoliz skeletnykh myshts liagushki.

It was shown in the experiments on isolated sartorius muscles of the frog that insulin increased endogenous respiration by 10 mm3 O2 hr per gramm of wet weight. The effect of insulin and epinephrine on respiration is additive. Insulin in middle (5--50 milliunits/ml) and low, physiological, (50 microunits/ml) concentration does not induce acceleration of glycolyses. The conclusion was confirmed that the increase of the endogenous respiration by insulin cannot be accounted for by the mobilization of the substrate of glycolysis. In the presence of epinephrine, the low concentration (50 microunits/ml) of insulin induces the decrease of the content of glucose-6-phosphate. It is probably connected with the influence of insulin on the concentration level of the cAMP.