Transformation of substrate specificity of EcoRl restrictase by glycerol

In the presence of glycerol, EcoRl restriction endonuclease hydrolyzes DNA into a larger number of fragments than under ordinary conditions. On the addition of glycerol to 50% concentration, this enzyme begins to act by what is called the EcoRl' type of restriction, which was producible experimentally only by reducing the ionic strength and increasing the pH of the solution. However, under these extremal conditions, the enzyme is quickly inactivated and does not give reproducible results, especially during the hydrolysis of high-molecular-weight DNA. The conditions found for manifestation of EcoRl' activity yield reproductible results, which is essentially equivalent to the discovery of a new restriction endonuclease.The nomenclature of the restriction enzymes follows that of Smith and Nathans [6].Laboratory of Biochemistry, D. I. Inanovskii Institute of Virology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR S. S. Debov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 7, pp. 46–48, July, 1977.     

Analysis of the effect of morphine and trimeperidine on the uptake and liberation of noradrenalin by myocardial tissue

The effect of morphine and trimeperidine on the concentration, uptake, and liberation of noradrenalin (NA) in the rat myocardium was investigated. Trimeperidine lowers the NA level in the myocardium. Morphine does not affect the liberation of NA-¹⁴C from the isolated perfused heart, whereas trimeperidine significantly increases it, affecting both the slow and the rapid release of the mediator. Trimeperidine does not affect the uptake of NA-¹⁴C by the perfused heart but morphine significantly lowers it. Competition between morphine and NA is characterized by an incomplete inhibition effect: Morphine and NA mutually affect the affinity of each other for the receptor and their interaction depends on their relative concentrations.Laboratory of Pharmacology of the Cardiovascular System, Institute of Pharmacology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 11, pp. 1345–1347, November, 1976.     

Role of injury in the appearance of “activated” smooth muscle cells

In experiments on rats the ultrastructure of the muscle tissue of the inferior vena cava after disturbance of the outflow of blood, of the muscular coat of the stomach after resection of 50% of its fundus, and of the muscular coat of the cecum after constriction of its ascending portion was studied. Activation of smooth muscles was shown to reflect the phase of injury to the ultrastructure of the cells, followed by processes of intracellular regeneration. Analysis of the ratio between DNA-synthesizing and activated cells showed the local origin of the latter from differentiated myocytes.Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR. No. 4 Main Board, Ministry of Health of the USSR. Institute of Human Morphology, Academy of Medical Sciences of the USSR. Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 7, pp. 112–115, July, 1977.     

A low-molecular-weight homogeneous fraction of the thymus stimulating immunogenesis

The effect of a purified acetic acid extract of thymus (thymarin) and of three of its fractions obtained by ion-exchange chromatography, and consisting of individual substances of polypeptide nature, on the immune response was studied in mice immunized with sheep's erythrocytes. Thymarin and one of its fractions with a molecular weight of about 5000 were shown to have a marked stimulating action on the thymus-dependent immune response (the formation of cells producing IgM and IgG antibodies and the circulating antibody level).Department of Microbiology and Immunology, Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR V. I. Ioffe.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 7, pp. 56–58, July, 1977.     

Confirmation of the hypothetical diffusion barrier in the region of the Ranvier node of myelinated nerve fibers

Experiments were carried out on single nerve fibers with a covered node. The nerve fiber was isolated together with one to three fragments of neighboring fibers adjacent to the node and which were firmly connected to the nodal ends of the myelin sheath by means of numerous connective-tissue membranes, thereby strengthening the node and protecting it against stretching during dissection. In potassium-free solution after-hyperpolarization of the nerve fiber membrane with an amplitude of 2.7 mV develops immediately after the end of the spike. Its origin is connected with maintenance of the increased potassium permeability of the membrane. During repetitive stimulation of the covered node the amplitude of after-hyperpolarization falls successively, as a result of a decrease in the outward potassium current caused by a reduction in the potassium electrochemical gradient. These observations are regarded as confirmation of the hypothesis expressed previously on the existence of a diffusion barrier in the region of the Ranvier node due to accumulation of K⁺ in the juxtamembranous space.Department of Anatomy and Physiology of Man and Animals, Ul'yanovsk Pedagogic Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Chernigovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 11, pp. 517–519, November, 1978.     

A Possible Mechanism for the Dopamine-Evoked Synergistic Disinhibition of Thalamic Neurons Via the “Direct” and “Indirect” Pathways in the Basal Ganglia

The mechanism of synaptic plasticity which we have previously proposed for striatal spiny neurons, along with published data on the predominance of dopamine-sensitive D1/D2 receptors on strionigral/striopallidal neurons, was used as the basis to propose the hypothesis that the induction of long-term potentiation/depression of the efficiency of the cortical inputs to these cells may result from the excitatory/inhibitory actions of dopamine on the activity of the neurons originating the direct and indirect pathways through the basal ganglia. Thus, the action of dopamine increases disinhibition of thalamic neurons via the direct pathway and decreases their inhibition via the indirect pathway. Both effects lead to increases in the activity of thalamic cells and in the activity of the efferent neocortical neurons which they excite. The actions of dopamine on striosomal neurons, which mainly have D1 receptors, may also be to induce long-term potentiation of cortical inputs. This effect should lead to increased inhibition of dopaminergic cells and decreases in their dopamine release, which may promote the maintenance of a stable dopamine concentration in the cortex-basal ganglia-thalamus-cortex neural network.     

Inhibition of passive cutaneous anaphylaxis by dipeptides

The action of certain dipeptides (L-alanyl-histidine, L-alanyl-histidine, histidyl-leucine, and glycyl-L-histidine) and of histidine itself on passive cutaneous anaphylaxis was studied in guinea pigs. L-alanylhistidine (carnosine) and L-alanyl-histidine were found to inhibit passive cutaneous anaphylaxis. Histidyl-leucine, glycyl-histidine, and histidine had no inhibitory action on passive cutaneous anaphylaxis.Allergologic Research Laboratory, Academy of Medical Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 10, pp. 460–462, October, 1977.     

Peroxidation of lipids and degeneration of photoreceptors in the retina of rats with avitaminosis E

The formation of peroxidation products of lipids (hydroperoxides, dialkyl peroxides, intermolecular cross linkages) is sharply intensified in the retina of rats with alimentary avitaminosis Ein vivo and degeneration of the photoreceptors (mainly the layer of outer segments of the rods) develops. The experimental results are discussed on the basis of views regarding the antioxidant mechanism of action of -tocopherolin vivo.Laboratory of Physical chemistry of Biological Membranes, Departament of Biochemistry, Biological Faculty, M. V. Lomonosov Moscow State University. Institute of Chemical Physics, Academy of Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR S. E. Severin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 4, pp. 411–413, April, 1977.     

Heterogenous antigens in vaccine preparations ofVibrio cholerae

Serological similarity was found between antigens of the human small intestine, stomach, and liver and antigens of various fractions of cholera vibrios. An antigenic similarity was found on testing the heart and kidney. Heterogenous antigen was found not only in somatic antigen ofV. cholerae strain 569 (B), but also in the cholerogen, the toxoid which is the most widely used prophylactic preparation in use at the present time, obtained from it.Mikrob Plague Research Institute, Ministry of Health of the USSR. Research Laboratory of Experimental Immunobiology, Academy of Medical Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 8, pp. 961–962, August, 1976.     

Characteristics of hepatocytes containing α-fetoprotein in regenerating mouse liver

After poisoning SWR mice of different ages with single or repeated doses of CCl₄ vapor the synthesis of the embryo-specific protein -fetoprotein (-FP) was induced. The greatest rise in the -FP level was observed in mice under 1 month old. In sections through the liver regenerating after CCl₄ poisoning, -FP was found in hepatocytes indistinguishable from the main population: in small cells in young animals and in large, polyploid hepatocytes in the repeatedly poisoned mice. The only distinguishing feature of the -FP-containing cells after poisoning of the mice with different doses of CCl₄ was that most of them were on the boundary with the necrotic zone. A similar localization of -FP-containing hepatocytes was observed when two other hepatotoxins were used: paracetamol and allyl alcohol.Laboratory of Immunochemistry and Diagnosis of Tumors, N. F. Gamaleya Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR P. A. Vershilova.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 7, pp. 97–101, July, 1977.     

The rhombencephalon and vasomotor reflexes to impulses in somatic A-fibers

Cats were decerebrated so that the medulla preserved its connections with a greater or lesser part of the pons, after which they were immobilized with flaxedil or succinylcholine and the response of their arterial blood pressure (BP) to volleys of impulses in various subgroups of fibers of the tibial nerve (frequency of volleys 10 sec^–1) was investigated. Impulses in A + A₁-afferents and the most excitable fraction of A₂-afferents lowered BP in all animals. Application of impulses in all A₂-afferents potentiated the fall in BP in 79% of the experiments and led to a rise in BP in only 21% of the experiments. The addition of impulses in A₃-fibers to the afferent flow either did not change the mean decrease in BP or led to a small or sometimes more considerable increase in BP. The critical factor producing a sharp reduction in the pressor reflexes or their replacement by depressor reflexes was the integrity of the structures of the pontobulbar junction and the most rostral part of the medulla. This region of the hindbrain thus contains formations causing tonic depression of the excitatory action of impulses in somatic A-afferents on vasoconstrictor neurons and which thereby unmask the existence of an inhibitory component of their action on these neurons. In unanesthetized cats this action of hindbrain structures is depressed tonically by the mesencephalon.Laboratory of Biophysics and Pathophysiology of the Circulation, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 11, pp. 519–522, November, 1978.     

Ultrastructure of conjugates of cytolytic T lymphocytes and target cells

Conjugates of target cells and cytolytic T lymphocytes, isolated on the 11th day after alloimmunization, were investigated. Conjugates were formed by small and medium-sized lymphocytes, in the cytoplasm of which mature secretory granules, crystalloid structures, and lipids were found. The lymphocyte was spherical in shape and its area of contact with the target cell did not exceed 5–15%. Cytolysis of the target cells was observed after incubation for 30–60 min. The lymphocyte became flatter, its nucleus became oval in shape, and the area of its contact with the target cell increased. Meanwhile, hypertrophy and a change in the orientation of the Golgi complex were found in the zone of contact with the target cell, fusion of the secretory granules with the lipids and crystalloid structures took place, and immature secretory granules and vacuolar degeneration of the mitochondria appeared. Peeling of the lymphocyte membrane was observed, and structures connected with it and called membranosomes are described. It is suggested that secretory processes are activated in the cytoplasm of cytolytic T lymphocytes during their interaction with target cells.Laboratory of Systemic Blood Diseases, Oncologic Scientific Center, Academy of Medical Sciences of the USSR. Department of Electron Microscopy, N. F. Gamaleya Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. M. Zhdanov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 5, pp. 560–565, May, 1978.     

Ribonuclease activity of the “myofibrillary” fraction of normal and autolyzed muscle tissue

The separation in a sucrose gradient of the myofibrillary fraction of normal and autolyzed muscle tissue gave 4 components. During post-mortem destruction of the tissue there was observed a slight decrease of the myofibrillary fraction yield and also certain changes in the distribution of protein between different components. Under the selected conditions RNase activity was found in all 4 components. During the course of autolysis enzymatic activity increased in the whole myofibrillary fraction, as well as in the lysosomal-mitochondrial components of myofibrils.Research Laboratory, Ministry of Health of the USSR, Moscow. Translated from Buylleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 5, pp. 533–537, May, 1978.     

Mechanism of action of nonachlazine on nervous control over the coronary circulation

The new antiaginal drug nonachlazine, in experiments on anesthetized cats and dogs, inhibited the response of reflex decrease of the blood flow into the coronary arteries. In freely behaving cats nonachlazine also inhibited reflex changes in the blood flow in the system of the common carotid artery and reduced pressor vasomotor reflexes. Nonachlazine selectively inhibited vasoconstrictor impulses from A-afferent fibers of spinal nerves, i.e., it acts on the vasomotor component of the primary nociceptive response. This mechanism may perhaps lie at the basis of the relief of the pain syndrome by nonachlazine in ischemic heart disease.Laboratory of Pharmacology of the Cardiovascular System, Institute of Pharmacology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 3, pp. 319–322, March, 1976.     

Action of phytohemagglutinin on transplantable human cells

Agglutinating and growth-stimulating properties of phytohemagglutinin (PHA) preparations were studied in experiments on transplantable human cells (clonal line HeLa k-41 and Cave). PHA and its -globulin fraction were found to possess weak hemagglutinating properties for human erythrocytes of groups A, B, and O, but strong cytoagglutinating properties with respect to HeLa k-41 and Cave cells. With large doses of PHA (100 and 500 g/ml) proliferation and the mitotic index of the cells of the cultures were lower but the percentage of dead cells and the agglutinin titer in the preparations were higher (1:256). With smaller doses of PHA (5 and 25 g/ml) growth was much more intensive and the percentage of dead cells was smaller. The agglutinin titer in the preparation fell to 1:16–1:32. The -globulin fraction of PHA had the strongest growth-stimulating action and gave the smallest number of dead cells. However, the agglutinin titer in the preparations was high (1:128). It is concluded that the inhibitory and growth-stimulating action of PHA preparations on transplantable human cells is directly linked with the agglutinin content in the preparations, for the -globulin fraction of PHA had the strongest cytoagglutinating and growth-stimulating action.Research Laboratory of Experimental Immunobiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. N. Zhukov-Verezhnikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 8, pp. 970–972, August, 1976.     

Effect of adrenergic receptor blocking agents on mitotic activity of the regenerating liver

The -adrenergic blocking drug phentolamine was injected into male rats 1 h before resection of 70% of the liver and again 24 h after the operation. Phentolamine inhibited mitotic activity of the regenerating liver. Two injections of propranolol, a -adrenergic blocking drug, at the same times caused an increase in mitotic activity. It was concluded that adrenalin, which excites -adrenergic receptors, may inhibit regeneration. By its action through -adrenergic receptors, however, adrenalin stimulates this process.Department of Physiology of Animals, N. G. Chernyshevskii Saratov University. Central Scientific-Research Laboratory, Saratov Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 11, pp. 1373–1374, November, 1976.     

Synthesis of α-fetoproteinin vitro by human hepatocytes,singly and in microcolonies

By a combination of microelectrophoresis and precipitation in polyacrylamide gel, -fetoprotein (-FP) produced by single hepatocytes and by microcolonies of hepatocytes was determined. Liver cells from 6–13-week-old human fetuses were cultivatedin vitro for 2–5 days. -FP was found to be produced in amounts of between 70 and 800 pg per cell by 23 of 28 single hepatocytes and by 89 of 91 microcolonies consisting of 2 to 35 cellsLaboratory of Immunochemistry and Diagnosis of Tumors, N. F. Gamaleya Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR. Laboratory of Human Cytogenetics, Institute of Medical Genetics, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR L. M. Shabad.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 4, pp. 481–484, April, 1977.     

Determination of complete nucleotide sequence of <Emphasis Type="Italic">Hibiscus latent Singapore virus</Emphasis>: Evidence for the presence of an internal poly(A) tract

Summary. We have sequenced the complete genome of a hibiscus-infecting tobamovirus, Hibiscus latent Singapore virus (HLSV). The experimental host range of HLSV is similar to that of another distinct species of hibiscus infecting tobamovirus, Hibiscus latent Fort Pierce virus (HLFPV). The genomic structure of HLSV is similar to other tobamoviruses in general. It consists of a 5 untranslated region (UTR), followed by ORFs encoding for a 128kDa protein and a 186kDa readthrough protein, a 30kDa movement protein (MP), 18kDa coat protein (CP) and a 3 UTR. The unique feature of HLSV is the presence of a poly(A) tract within its 3 UTR. In our previous work, we have reported MP and CP sequences of HLSV and its phylogenetic analysis. Here we report the complete nucleotide sequence of HLSV, phylogenetic analysis of the nucleotide and amino acid sequences of 128/186kDa ORFs and the presence of a uniquely located poly(A) tract within the 3 UTR.The GenBank accession numbers of the sequences reported in this paper are AF400156, AF400157 and AY497578, respectively.     

Thalamic inhibition of locomotion induced by mesencephalic stimulation

By stimulation of a region of the thalamus with its center corresponding to Horsley-Clarke coordinates A7, L2, H2, locomotion of the lightly anesthetized cat with an intact brain can be inhibited, whether evoked by stimulation of the subthalamic or of the mesencephalic locomotor region.Laboratory of Physiology of Movements, Institute for Problems in Information Transmission, Academy of Sciences of the USSR, Moscow. (Presented by Academician V. N. Chernigovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 8, pp. 903–906, August, 1976.     

Effect of prolonged hypokinesia on the water and fat composition of the human body

The combined effect of prolonged hypokinesia (30–49 days) and differences in the body position relative to the gravitational vector on the composition of the body was studied in healthy men. The total body water content depends more on the position of the body in space than on the restricted mobility. In the antiorthostatic position, the loss of water takes place chiefly during the first few days. As a result of prolonged hypokinesia the lean mass of the body is reduced and so also is its water content. The water content is rapidly restored when motor activity is resumed.Institute of Medico-Biological Problems, Ministry of Health of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 3, pp. 279–281, March, 1976.