A biosynthesis activity of Streptomyces recifensis var. lyticus.

The structure of enzyme complex synthesized of soil streptomycete was investigated. Fractionation and purification of enzymes have allowed to identify a line of hydrolases: proteinases, amylases, DNA-ses, cellulases and also glycosidases and endopeptidases with lytic action. Their properties were studied.

[Oxidative activity and accumulation of metabolites in gonococcal and staphylococcal plasmid-containing strains].

A higher rate of glucose oxidation by antibiotic-resistant staphylococcus and gonococcus strains has been established; at the same time the sensitive strains are characterised by more intensive oxidation of pyruvate and acetate as compared with the resistant strains. High rate of lactate accumulation by antibiotic-resistant strains has been marked for the studied staphylococci strains. Antibiotic-resistant strains of gonococci are characterised by more intensive accumulation of acetate as the end product of glucose catabolism.

Imaging stochastic spatial variability of active channel clusters during excitation of single neurons.

Topographical maps of membrane voltages were obtained during action potentials by imaging, at 1 microm resolution, live dissociated neurons stained with the voltage sensitive dye RH237. We demonstrate with a theoretical approach that the spatial patterns in the images result from the distribution of net positive charges condensed in the inner sites of the membrane where clusters of open ionic channels are located. We observed that, in our biological images, this spatial distribution of open channels varies randomly from trial to trial while the action potentials recorded by the microelectrode display similar amplitudes and time-courses.

[Effect of rhenium complexes with organic ligands on acid resistance of human erythrocytes].

The authors showed stabilizing effect of rhenium binuclear cluster compounds with organic ligands on erythrocytic membranes. Estimation of functional condition of cells was studied by a chemical fragility method. Biphase type of rhenium complexes concentration curves stabilization has been found out; the influence of organic radicals and axial substructures (Cl- and Br-) on degree of stabilization has been showed.

[The effect of glucose on the biosynthesis of extracellular enzymes by Streptomyces recifensis var. lyticus 2435 and its mutants].

Different glucose concentrations have been studied for their effect on biosynthesis of bacterio- and proteolytic enzymes in Streptomyces recifensis var. lyticus 2435 and strains II-29 and 2P-15 obtained from the latter. It has been established that synthesis of enzymes by the parent strain 2435 was subjected to catabolite repression: synthesis of proteolytic and staphylolytic enzymes was the most sensitive to glucose, synthesis of glucosidases was less sensitive.

Activity-dependent reconfiguration of the effective dendritic field of motoneurons.

A neuron in vivo receives a continuous bombardment of synaptic inputs that modify the integrative properties of dendritic arborizations by changing the specific membrane resistance (R(m)). To address the mechanisms by which the synaptic background activity transforms the charge transfer effectiveness (T(x)) of a dendritic arborization, the authors simulated a neuron at rest and a highly excited neuron. After in vivo identification of the motoneurons recorded and stained intracellularly, the motoneuron arborizations were reconstructed at high spatial resolution.

[Investigation of oxosubstances in plant leaf lipids].

Surface lipids of plant leaves of different groups were investigated by spectral, chromatographic and functional analysis methods. Absence of oxosubstances in surface lipids of coniferous and their characteristics in tropical species were shown. Functions of oxosubstances are discussed.

[Spectral and thermographic characteristics of surface lipids from various plants].

Spectral (IR) and thermogravimetrical properties of surface lipids of two coniferous species, differing during molecular weights of their components, were investigated in the process of ontogenic development. Different mechanisms of surface lipid formation in leaves of the investigated species are shown. It is supposed that low temperature endothermic effect, which is connected with phase transfer of the surface lipids amorphous part may play functional role in formation of stability of plants to gases.

[Features of carbohydrate catabolism in plasmid-containing strains of staphylococcus].

It was established, that the antibiotic resistant strains of Staphylococcus aureus differed from susceptible strain in the intensity of the catabolic reactions of carbohydrate transformation and in the accumulation of metabolism central products, that is a result the R-plasmid presence in them.

[The effect of a soil extract on the development of Bacillus thuringiensis and on its synthesis of an insecticidal endotoxin].

Selection of effective and inexpensive nutrient medium for cultivation of entomopathogenic bacteria Bacillus thuringiensis was carried out. The medium with molasses [correction of patoka], corn extract and mineral salts has been chosen. Addition of a soil extract to the medium enhanced growth of microorganisms, increased the rate of culture development, the yield of spore-crystalline material and quantity of synthesized endotoxin.

[Inclusion of protein and nucleic acid precursors by staphylococci that are sensitive and resistant to antibiotics].

We have convey comparative study of including intensity of marking protein predecessors and nucleic acids by initial strains of Staphylococcus aureus sensitive to antibiotics and strains, which contain plasmids of resistance to different antibiotics. Shown including intensity increase of adenine, uridine, thymidine and marked amino acids by strains which contain plasmids of resistance to different antibiotics to compare with unplasmids variant. On the base of receiving results we may affirm that in general we observe intensification of protein synthesis and separate staves nucleic acid synthesis by observing staunch strains.

[A comparative analysis of energy process inhibitors on the efficiency of phage infection in staphylococci].

The study of the effect of KCN, DCCD and CCCP as inhibitors of the energy yielding processes showed that the efficacy of phage infection depended on respiration, proton ATPase, and proton electrochemical potential of hydrogen ions. There was a 49.5-68.

[Interaction of adhesion proteins with structural components of cytoskeleton in animal cells].

The short characteristic of cell adhesion molecules and the main components of cytoskeleton are submitted at the present review. Structural and functional peculiarities of these proteins are presented. On the basis of different sources an attempt to clarify the possible mechanism of the interaction of adhesion proteins cytoskeleton structure has been done.

Geometry-induced features of current transfer in neuronal dendrites with tonically activated conductances.

The impact of dendritic geometry on somatopetal transfer of the current generated by steady uniform activation of excitatory synaptic conductance distributed over passive, or active (Hodgkin-Huxley type), dendrites was studied in simulated neurons. Such tonic activation was delivered to the uniform dendrite and to the dendrites with symmetric or asymmetric branching with various ratios of branch diameters. Transfer effectiveness of the dendrites with distributed sources was estimated by the core current increment directly related to the total membrane current per unit path length.

[A comparison of the developmental characteristics of Neisseria gonorrhoeae and Staphylococcus aureus cultures on nutrient media of different compositions].

The growth parameters of gonococcus and staphylococcus strains in liquid medium were determined. The generation time varied within the limits from 0.8 to 1.

[Role of proton-motive force in the conjugative DNA transport in Staphylococci].

Sensitivity of the conjugative process in staphylococci to the action of uncouplers of oxidative phosphorylation and inhibitors of electron transport systems have been proved, that testifies to the energy-dependent character of conjugative transport of DNA. Proceeding of the conjugation process depends upon the generation of delta microH+ on the membrane of both the donor and recipient cells. contribution of protonmotive forces to providing for the transfer of plasmids during conjugation to staphylococci has been defined.

Effect of experimental hyperphenylalaninemia on the postnatal rat brain.

The molecular mechanism of the disturbance of brain development caused by phenylketonuria remains mostly unknown. We have studied three molecular markers that reflect the development of neurons, glia and the extracellular matrix of the postnatal rat brain in an animal model of hyperphenylalaninemia, in order to elucidate the possible mechanism by which increased phenylalanine influences brain development. The content of NCAM, GFAP and hyaluronate-binding activity were compared in cerebellum and telencephalon of normal rats and those subjected to high phenylalanine.

Spatial electrical patterns in simulated neuronal dendrites.

Steady state longitudinal distributions of (a) the density of channels conducting an inward transmembrane current of cations, (b) the submembrane concentrations of these cations, and (c) the resting membrane potential, were investigated in a phenomenological model of a cylinder-shaped dendritic process of the neuron. It was found that spatially non-uniform patterns of these distributions occur only if one of the following conditions held (i) an increase in the intracellular concentration of cations conducting an inward passive transmembrane current amplified the active efflux of those cations by the pump and attenuated their passive influx through the voltage dependent channels, with amplification of the efflux lower than attenuation of the influx; (ii) molecules of mobile channels bore a negative electrophoretic charge exposed to the intracellular space and were subject to lateral electrodiffusion in the membrane; (iii) the cations induced a further release of cations from intracellular stores. Numerical simulation studies of the membrane with Na and K channels and Na/K pumps with conditions (i) and (ii) have demonstrated the possibility of the creation of inhomogeneous patterns in the neurites.

Differential back-invasion of a single complex dendrite of an abducens motoneuron by N-methyl-D-aspartate-induced oscillations: a simulation study.

Intracellular recording of abducens motoneurons in vivo has shown that ionophoretic applications of N-methyl-D-aspartate produced long-lasting membrane potential oscillations including a slow depolarization plateau with a burst of fast action potentials. This complex N-methyl-D-aspartate pattern was reproduced in the model of abducens motoneuron in vivo identified, intracellularly stained with horseradish peroxidase and reconstructed at high spatial resolution. The excitable soma of the simulated cell contained voltage-gated Ca, Na and K conductances, N-methyl-D-aspartate-gated voltage-sensitive Ca-Na-K conductance and Ca-dependent K conductance.

Local mechanisms of phase-dependent postsynaptic modifications of NMDA-induced oscillations in the abducens motoneurons: a simulation study.

1. In vivo experiments have shown that extracellular microelectrophoretic application of N-methyl-D-aspartate (NMDA) induced oscillatory plateau potentials with bursts of action potentials in rat abducens motoneurons. The period of these slow NMDA oscillations could be altered by single trigeminal non-NMDA excitatory input delivered at low frequency during the NMDA oscillations.

Electro-geometrical coupling in non-uniform branching dendrites. Consequences for relative synaptic reflectiveness.

The relationships between somatofugal electronic voltage spread, somatopetal charge transfer and non-uniform geometry of the neuronal dendrites were studied on the basis of the linear cable theory. It is demonstrated that for the dendritic arborization of arbitrary geometry, the path distribution of the relative effectiveness of somatopetal synaptic charge transfer defined as in Barrett and Crill (1974) is identical to that of the somatofugal steady electronic voltage normalized to the voltage at the soma. The features of both distributions are determined by breaks in the voltage gradient (the slope of monotonic voltage decay) at the sites of local non-uniformity of the dendritic geometry, such as abrupt change in diameter and asymmetric branching.

Electrotonic clusters in the dendritic arborization of abducens motoneurons of the rat.

Following reconstruction with high spatial resolution of the 3-D geometry of the dendritic arborizations of two abducens motoneurons, we simulated the distribution of electronic voltage over the whole dendritic tree. Here, we demonstrate that the complex stochastic electronic structure of both motoneurons can be reduced to a statistically significant small set of well discriminated clusters. These clusters are formed by dendritic branches belonging to different dendrites of the neuron but with similar electronic properties.

Lateral patterns of the neural cell adhesion molecule on the surface of hippocampal cells developing in vitro.

In monolayer cultures of hippocampal neurons from newborn rats, an immunocytochemical quantitative study was carried out to investigate age-dependent arrangement of the neural cell adhesion molecules in different parts of cell membranes. On the fifth and 12th day in vitro, neural cell adhesion molecules were labelled with specific antibodies and protein A conjugated to colloidal gold particles. Samples of randomly selected electron micrographs that displayed labelled membrane fragments of cell bodies, growth cones, and axons were numerically analysed for the five- and 12-day in vitro neurons.

Changes in the neural cell adhesion molecule patterns on the rat glial cell surfaces with development and contact formation in vitro.

In monolayer cultures of newborn rat hippocampal cells, immunogold-labelling at the electron microscope level was used to study quantitatively the neural cell adhesion molecule (N-CAM) arrangement on the surface of glial soma and processes on 5 and 12 days in vitro (DIV). Four corresponding samples of micrographs were formed. To quantify the labelling, a stochastic geometry approach was used.