Generation of hard twisted photons by charged particles in cholesteric liquid crystals.

We study the radiation from charged particles crossing a cholesteric plate in the shortwave approximation when the wavelength of photons is much smaller than the pitch of the cholesteric helix, whereas the escaping angle of the photon and the anisotropy of the permittivity tensor can be arbitrary. The radiation of photons is treated in the framework of quantum electrodynamics with classical currents. The radiation of the plane-wave photons and the photons with definite projection of the angular momentum (the twisted photons) produced by charged particles crossing the cholesteric plate and moving rectilinearly and uniformly is considered.

[Cellular changes in the paraurethral zone of the experimental animals in exposure to collost gel].

An experimental trial of the collagen gel collost was made on Wistar white female rats aged 68 and 30-36 months. 7 and 15% collost gel (the first Russian collagen gel produced from cattle skin) was implanted in paraurethral region of the animals. The connective tissue cells in the zone of collost gel injection was studied histologically, immunohistochemically, electron microscopically.

[The radical minimal access thoracoplasty by funnel chest in adults].

A new technique of radical thoracoplasty, performed with a small size incision, using the sternocostal complex fixation with nitinol plates with shape memory and the surgical toolkit required for the purpose, has been successfully introduced. 23 patients underwent surgery using the technique. Tree patients had early postoperative complications: 2 cases of exudative pleurisy and 1 case of bronchitis aggravation.

[Radical thoracoplasty by the funneled thorax malformation in adults].

Early and long-term results of radical thoracoplasty in 114 adult patients with funnel chest are presented. The Sulamaa-Paltia operation was performed in 24 patients, thoracoplasty with sternocostal complex fixing by arcuated nitinol plates was made in 30 patients. Thoracoplasty with sternocostal complex fixing by M-shaped nitinol plates was performed in 60 cases.

[Determination of free d-biotin--comparison of instrumental and non-instrumental methods of analysis].

Simple methods for determining free d-biotin were developed based on the latex agglutination reaction inhibition and competitive ELISA. Biotin-binding protein Str used as a biospecific marker was immobilized on the surface of colored polyacrolein latex particles or a nitrocellulose membrane. The sensitivity of both methods of the free d-biotin assay, which take 1.

[Stability of Escherichia coli to the membranotropic antibiotic gramicidin S].

The work was aimed at studying the effect of gramicidin S on the intact cells, spheroplasts and membrane specimens of Escherichia coli K12S with the natural resistance to this antibiotic. The resistance was shown to be caused by the barrier properties of the cell wall: the spheroplasts were highly sensitive to the lytic action of gramicidin S. The differences in the sensitivity to gramicidin S of substrate oxidation carried by the membranes of E.

[Study of the adaptation resistance in bacteria to membrane active polypeptide antibiotics].

Variants of Micrococcus lysodeikticus resistant to 100 micrograms/ml of gramicidin S with preserved resistance in subcultures on media without the antibiotic were isolated as a result of prolonged adaptation on a solid medium with increasing concentrations of gramicidin. The sensitive and resistant cells did not differ by their ability to bind gramicidin. Under the antibiotic effect permeability of the cytoplasmic membranes of the intact cells in the sensitive bacteria appeared to be impaired to a greater extent than that of the membranes of the cells in the resistant variant.

[Physicochemical mechanisms of the action of gramicidin S on a model membrane].

Influence of gramicidin S on electric parameters of nitrocellulose ultrafilter as a biomembrane model was studied, the ultrafilters being impregnated with fatty acids or their ethers. It was shown that addition of the antibiotic to the solution over one side of the model membrane resulted in generation of electric potential. With increasing of the drug concentration by one order there was observed more than a 10-fold drop in the membrane resistance while the electric capacitance actually remained unchanged.

[Effect of L-arabinose and sucrose on the biosynthesis of heliomycin by its producer Streptomyces olivocinereus 11-98].

When Streptomyces olivocinereus 11-98 MFU was grown in media containing L-arabinose or sucrose there was observed a converse relation between the culture growth and heliomycin biosynthesis. In media with two carbon sources: L-arabinose and glycerol or sucrose and glycerol at first L-arabinose or sucrose was consumed while the level of glycerol consumption remained low as compared to the control. After exhaustion of the first carbon source there was observed increased consumption of the second one i.

[The action of gramicidin S on the ionic permeability of bilayer lipid membranes].

The effect of cyclic decapeptide of gramicidin S on electrical conductivity of bilayer lipid membranes has been studied. The integral conductivity of bilayer has been shown to increase with the growth of antibiotic concentration. The integral conductivity increase occurs as series of conductivity discrete leaps, differing in amplitude from fluctuations of conductivity caused by linear gramicidins.

[Comparative study of the surface-active properties of gramicidin S and its derivatives by polarography].

Gramicidin S and its derivatives by the free amino groups of the ornithine moieties were studied with respect to their effect on interface tension of mercury and the polarographic background for comparative estimation of the surface active properties of these compounds. The same way as the compounds preserving their main properties, the neutral and acid derivatives lowered the polarographic maximum. No correlation between the level of the antimicrobial and membrane activity and the surface active properties of the tested compounds was observed.

[Action of different types of gramicidin S derivatives on bacterial cells and protoplasts].

The work was concerned with studying the effect of gramicidin S derivatives with modified free amino groups of ornithine residues on bacterial cells and protoplasts. The substitution of the amino groups with neutral or carboxyl-containing groups eliminated or sharply decreased the antibacterial activity of gramicidin S, its binding to the cells, and the ability to change the permeability of the cytoplasmic membranes of the intact cells. However, the neutral derivatives and the derivative with acidic properties showed a considerable lytic activity when they were incubated with the protoplasts of Micrococcus lysodeikticus, Bacillus megaterium and Bacillus subtilis.

[Effect of phosphates on the membrane activity of gramicidin S].

The membrane activity of gramicidin S against intact cells of staphylococci and micrococci determined by the loss of intracellular low-molecular compounds with the adsorption maxima at 260 nm by the bacteria markedly increased in the presence of phosphates. Acetate and hydrochlorides had no effect on the membranotropic action of the antibiotic. Analogous results were obtained for gramicidin S derivatives by free ornithine amino groups possessing basic and antibiotic activity.

[Optical density changes in bacterial protoplast suspensions exposed to membrane-active antibiotics].

The effect of membrane active antibiotics, such as gramicidin S, its derivatives and carbonyl-conjugated pentaens on suspended bacterial protoplasts resulted in lysis of the protoplasts accompanied by a marked decrease in the optical density (OD) of the suspensions. However, when the drug concentrations were lower than those inducing the lysis, an increase in the suspension OD by 10-30 per cent as compared to the control values of the OD was often observed. The increase in the protoplast suspension OD was most pronounced with the use of the drugs with a relatively low lytic activity or under the conditions lowering the lytic activity of the antibiotics.

[Clinical and experimental study of dioxidine. Its antibacterial action].

The effect of dioxidine on the growth of freshly isolated clinical strains of microorganisms with various levels of resistance to antibiotics was studied. It was shown that strains of Ps.aeruginosa not resistant to carbenicillin, chloramphenicol and nalidixic acid were most sensitive to the drug.

[Effect of antibiotics on human lymphocyte mitogenesis].

The effect of some antibiotics on in vitro blast transformation of lymphocytes of healthy donors stimulated with phytohemagglutinin was studied. The stimulation level was estimated by incorporation of 3H-thymidine into lymphocytes. It was shown that minocycline had a markedly pronounced inhibitory activity.

[Possibility of reversing the action of the membranotropic antibiotic, gramicidin S, on bacteria].

The study on the possibility of eliminating gramicidin S from the bacterial cells which had adsorbed it showed that a part of the labeled antibiotic bound by the bacteria may be washed out with buffer or salines. When the cells which had adsorbed gramicidin S were treated with lecithin emulsion, a significant part of the bound antibiotic was transferred to the lecithin liposomes. This turned the gramicidin S effect to the cells: significant but not complete reduction of the membrane barrier properties and dehydrogenase reactivation.

[Effect of raised temperatures on the protein and RNA synthesis rate in yeasts].

The rates of incorporation of labelled precursors of protein (14C-DL-leucine) and RNA (14C-uracil) into the cells of synchronous yeast cultures of Pichia membranaefaciens, Hansenula anomala, Saccharomyces cerevisiae and Saccharomyces (fabospora) fragilis were studied at different temperatures. Synthesis of RNA and then of protein was inhibited in H. anomala if the temperature was increased above the optimal one.

[Effect of increased temperatures on RNA and protein synthesis in the cells of a synchronous Candida utilis culture].

The rate of incorporation of labeled precursors for RNA ([14C]uracil) and protein ([14C]DL-leucine) into the cells of the synchronous culture of Candida utilis VKMY-1668 (the optimum temperature of growth, 31--32 degrees C) was studied as a function of different temperatures (28, 31, 32, 34, 36, 38, and 41 decrees C). The yeast was grown on a simple mineral medium containing glycerol. RNA synthesis was found to be more susceptible to elevated temperature than protein synthesis: the maximum rate of incorporation was registered at 32--34 degrees C for [14C]DL-leucine and only at 32 degrees C for [14C]uracil (the rate of its incorporation at 34 degrees C decreased by 50% as compared to that at 32 degrees C).

[Action of copper ions and of unfavorable medium pH values on protein and RNA synthesis by Candida utilis cells].

The effect of copper ions and unfavourable pH values of the medium on the incorporation of labelled precursors of protein and RNA was studied in Candida utilis. Specific inhibition of protein synthesis by copper ions and alkaline conditions was found. No specific inhibition of protein or RNA was detected at low pH values of the medium.

[Heliomycin decrease in the pool of purine- and pyrimidine-containing compounds in bacterial cells].

Heliomycin inhibited formation of the pool or purine and pyrimidine containing compounds in the cells of the growing cultures of Staphylococcus aureus and Escherichia coli both in the lag phase at the maximum rate of formation of the pool of compounds absorbing at 260 nm and in the exponential phase. A decrease in the concentration of purine and pyrimidine containing compounds in the acid-soluble fraction of the cells by the antibiotic was not caused by the disturbed permeability of the membranes. Apparently, heliomycin interfered with the regulation of RNA synthesis, either directly or through its action on the energy metabolism of the cells.