[Influence of protein molecule conformation on the character of its interaction with a phospholipid bilayer]. / O vliianii konformatsii molekuly belka na kharakter ego vzaimodeistviia s fosfolipidnym bisloem.

The adsorption of lysozyme on mixed phosphatidyl choline-cardiolipin vesicles was studied at pH 4.0 and 6.0. The binding constants at both pH were determined at 0 and 22 degrees C. The presence of maximum on the adsorption isotherm at pH 6.0 was interpreted as an indication of the formation of two types of the protein-lipid complexes. This interpretation was confirmed by electron-microscopic observations. On the other hand, at pH 4.0 only one type of the protein-lipid complex was formed. The lysozyme conformation in solution and in the protein-lipid complexes was studied by circular dichroism. It was found that at acidic pH the lysozyme molecule contains a higher per cent of alpha-helix segments than at neutral pH. As follows from the measurements of lysozyme distribution in two phase systems the increase in alpha-helicity results in the formation of hydrophobic patches on the surface of the protein molecule. The results of the present work and of the previous studies of the interaction of red- and oxy- form of cytochrome C with phospholipid allow the conclusion that for peripheral proteins the nature of protein-lipid interactions is determined by the protein alpha-helix content and by hydrophobic pattern of the protein molecule surface.

[Influence of phospholipids of different natures on the structure of ferricytochrome c]. / Vliianie fosfolipidov razlichnoi prirody na strukturu ferritsitokhroma c.

Influence of the two types of lipid molecules (neutral and acidic phospholipids) on the structure of ferricytochrome c in lipid-protein complexes was studied with the use of circular dichroism and absorption spectroscopy methods. It was found that interaction of ferricytochrome c with acidic phospholipids (cardiolipin and phosphatidylinositols) brings about some changes in the protein conformation, while interaction with neutral phospholipid (phosphatidylcholine plus 10% lauric acid) does not. Some difference in the mode of interaction of different acidic phospholipids with ferricytochrome c was also observed. As evidenced by visual light absorption spectra, cardiolipin induced the disruption of hem--methionine 80 bond in the protein molecule, while phosphatidylinositols do not cause such an effect.

[Spontaneous and induced autoxidation of phospholipids during conformational rearrangements in outer segment membranes of frog retinal rods]. / Spontannoe i indutsirovannoe avtookislenie fosfolipidov pri konformatsionnykh perestroikakh membran naruzhykh segmentov palochek setchatki liagushki

Kinetics of spontaneous and induced by the system Fe+++ascorbate peroxide oxidation of lipids in the membranes of outer segments of frog retina rods has been studied. Free radical oxidation of phospholipids passes the same stages as liquid phase oxidation of alkenes. Docosahexaenoi fatty acid residue of phosphatidyletanolamine is the main substrate of autooxidation. The structural organization of photoreceptor membranes is the factor which controls the reaction rate of peroxide oxidation; and reconstructions in membrane organization (at rhodopsin photolysis) result in the changes of autooxidation rate of phospholipids in the membrane.

[Protein-lipid interactions during lipid peroxidation in photoreceptor membranes]. / Belok-lipidnye vzaimodeistviia pri perekisnom okislenii lipidov v fotoretseptornoi membrane

It has been shown that chemical modification of hydrophobic lipid phase (lipoperoxidation) of outer segments membrane discs of frog retina rods brings about weakening protein-lipid interactions in the photoreceptor membrane. As a result of this extraction of rhodopsin with anion detergent (sodium cholate) in the concentrations not exceeding the critical concentration of micelloformation increases, and spontaneous release of rhodopsin into water phase is observed. At the same time the number of phospholipid molecules extracted in lipoprotein rhodopsin complex from the membranes of outer segments decreases 3-4-fold.

[Adsorptive and catalytic properties of cholinesterase on phospholipid monolyers in different oxidation states]. / Adsorbtsionnye i kataliticheskie svoistva kholinésterazy na fosfolipidnykh monosloiakh razlichnoi okislennosti

Adsorption isotherm and enzymatic activity of protein interacting with the surface of solid carrier formed by oriented fat lipid chains of differently oxidized phospholipids have been studied. It has been found that the appearance of peroxide groups in fat acid chains results in a twofold decrease of protein limiting adsorption on the lipid monolayer. The data on enzymatic activity of proteins at variously filled suface with protein molecules indicate that the peroxide groups produce an activating effect under the conditions when protein interactions can be neglected. Superoxidation of phospholipid fat acids is suggested to be one of the mechanisms involved in the control of the processes proceeding on the membranes.

[Antioxidants as cytochrome stabilizers in endoplasmic reticulum membranes of rat liver in vivo]. / Antioksidanty kak stabilizatory tsitokhromov v membranakh éndoplazmaticheskogo retikuluma pecheni krys in vivo

It has been shown that synthetic antioxidant 4-methyl-2, 6-ditrebuthylphenole (ionole) inhibits free radical oxidation of phospholipids in the membranes of endoplasmic reticulum, increases the life time of cytochrome P-448 after its induction with 20 methylcholantrene.

[Lateral diffusion of the concanavalin A and immunoglobulin receptors on the surface of lymphocyte plasma membranes on exposure to antigen]. / Lateral'naia diffuziia retseptorov konkanavalina A i immunoglobulinov poverkhnosti plazmaticheskikh membran limfotsitov pri antigennom vozdeistvii.

The lateral diffusion of integral glycoproteins of lymphocyte plasma membranes is not described only in terms of Brown movement. The development of immune process to the thymus-dependent antigene in vivo induces changes in physico-chemical state of ConA and immunoglobulin receptors of the surface of immuno-competent cells revealed when studying cap formation in vitro.

[Interrelationship between structural and functional modifications in the membranes of the sarcoplasmic reticulum following lipid peroxidation]. / Vzaimosviaz' strukturnykh i funktsional'nykh perestroek v membranakh sarkoplazmaticheskogo retikulums pri perekisnom okislenii lipidov.

Structural and functional modifications of sarcoplasmic reticulum membranes from skeletal muscles by molecular oxygen was studied. Lipid peroxidation (accumulation of 5-10 nmoles hydroperoxides/mg lipids) results in membrane permeability increase for Ca2+-ions whereas the activity of Ca2+-dependant ATPase preserved unchanged. In the temperature range 5-30 degrees C decrease of solubilization parameter alpha (for nitroxide radical 2,2,6,6-tetramethylpiperidin-1-oxyl) was registered while alpha reached the control values at temperatures higher than 30 degrees C. Further increase in lipoperoxide content (more than 20 nmoles/mg lipids) lead to inhibition of Ca2+dependant ATPase. In this case alpha was lower than in intack membranes in the whole temperature interval investigated. The loss of Ca2+-accumulating capacity is explained on the basis of peroxide clusters formation in lipid bilayer regions of sarcoplasmic membrane. One of the mechanisms of Ca2+-dependant ATPase inhibition after lipid peroxidation is the deficiency of polyunsaturated fatty acyls in microenvironment of the enzyme.

[Role of lipid peroxidation in the pathogenesis of ischemic injury and the antioxidant protection of the heart]. / Rol' perekisnogo okisleniia lipidov v patogeneze ishemicheskogo povrezhdeniia i antioksidantnaia zashchita serdtsa.

It has been shown that an important link of the heart ischaemic damage in the infarction is the so-called lipid triad supervening in the lipid bilayer of cardiomyocyte membranes. This triad consists in the activation of the lipid peroxidation (LPO), phospholipase activation, and the detergent effect of high concentrations of fatty acids, that results in an increase of the membrane permeability for calcium and plays an important role in the transition from the reversible ischaemic damage to the irreversible. The LPO activation established by the authors in the myocardial infarction in the ischaemic and non-ischaemic zones seems to be the link triggering the lipid triad. Administration of the synthetic LPO inhibitors, antioxidants 2.6 - ditretbutyl - 4 - methyl phenol, or OP-6 significantly decreased the ischaemic necrosis area, fermentemia and disturbances of the cardiac contractility in experimental infarction.

[Effect of antioxidants on regeneration of protoplasts in the mycelial fungus Trichoderma reesei 6/16]. / Vliianie antioksidantov na regeneratsiiu protoplastov mitselial'nogo griba Trichoderma reesei 6/16.

The relative content of antioxidants in the mycelium of Trichoderma reesei 6/16 obtained by propagation of fungal protoplasts was shown to decrease (as compared to the initial culture taken for preparation of protoplasts) and restored only in the second generation of regenerated mycelium. In this respect, the effects of various antioxidants (beta-carotene, ascorbic acid, alpha-tocopherol, and ionol) on the frequency of regeneration of T. reesei 6/16 protoplasts were studied. beta-Carotene increased the viability of fungal protoplasts to the greatest extent. The effect of ascorbic acid depended on the presence of Fe ions. Ionol did not cause any measurable protective effect.

[Degradation of the herbicide atrazine by the soil mycelial fungus INBI 2-26(-)--a producer of cellobiose dehydrogenase]. / Razlozhenie gerbitsida atrazina pochvennym mitselial'nym gribom INBI 2-26(-)--produtsentom tsellobiozodegidrogenazy.

Nonsporulating mycelial fungi producing cellobiose dehydrogenase (CDH) and isolated from soils of South Vietnam with high residual content of dioxins are capable of growing on a solid medium in the presence of high atrazine concentrations (to 500 mg/l). At 20 and 50 mg/l atrazine, the area of fungal colonies was 1.5-1.2-fold larger, respectively, compared with control colonies of the same age, whereas development of the colonies at 500 mg/l atrazine was delayed by 5 days, compared with controls grown in the absence of atrazine. Surface cultivation of the fungus on a minimal medium with glucose as a sole source of carbon and energy decreased the initial concentration of atrazine (20 mg/l) 50 times in 40 days; in addition, no pronounced sorption of atrazine by mycelium was detected. This was paralleled by accumulation in the culture medium of extracellular CDH; atrazine increased the synthesis of this enzyme two- to threefold. Accumulation of beta-glucosidase (a mycelium-associated enzyme) and cellulases preceded the formation of CDH.

[Enzymatic hydrolysis of willow treated with a steam burst without preliminary water extraction with a high concentration of substrate]. / Fermentativnyi gidroliz obrabotannoi parovym vzryvom drevesiny ivy bez predvaritel'noi vodnoi ékstraktsii pri vysokoi kontsentratsii substrata.

A laboratory reactor equipped with a screw press was used for hydrolysis of steam-SO2 exploded willow Salix caprea by a composition of Trichoderma reesei and Aspergillus foetidus enzyme preparations at high substrate concentrations. Optimal conditions providing the maximal volume of hydrolysis syrup with maximal sugar concentrations were determined. Two different hydrolysis procedures were developed in order to exclude initial washing of steam-pretreated plant raw material by large volumes of water, which is necessary to eliminate the inhibitory effect of explosion by-products on enzymatic hydrolysis. The first procedure included a one-hour-long enzymatic prehydrolysis of the substrate, then separation of sugar syrup containing 40-60 g/l of glucose, 20-25 g/l of xylose, and up to 10% of disaccharides, as well as up to 35% of the initial enzymatic activity, then addition of a diluted acetate buffer (pH 4.5), and subsequent hydrolysis of the substrate by the adsorbed enzymes leading to the final accumulation of up to 140 g/l glucose and up to 15 g/l xylose. In the second scenario, the exploded willow was initially adjusted by alkali to pH 4.5 and then hydrolyzed directly by added enzymes for 24 hours. This procedure resulted in a nearly total polysaccharide hydrolysis and accumulation of up to 170 g/l glucose and 20 g/l xylose. The reasons of inhibition of enzymatic hydrolysis are discussed.

[Consumption of the triazine herbicide atrazine by laccase and laccase-free variants of the soil fungus Mycelia sterilia INBI-2-26]. / Potreblenie triazinovogo gerbitsida atrazina lakkaznym i bezlakkaznym variatami pochvennogo griba Mycelia sterilia INBI 2-26.

Asporogenic fungus Mycelia sterilia INBI 2-26 isolated from tropical soils with high residual dioxin content (as a result of Agent Orange defoliant treatment during the Vietnamese-American war) and capable of atrazine decomposition was treated to obtain protoplasts. This technique resulted in isolation of laccase-positive and laccase-negative clones. Atrazine consumption by liquid surface cultures of Mycelia sterilia INBI 2-26 was monitored by using enzyme immune assay and reversed phase HPLC. Atrazine (20 micrograms/l) stimulated fungal growth. Laccase-positive clone consumed up to 80% of atrazine within four weeks. However, no correlation of atrazine consumption and laccase activity in the culture medium was observed. Moreover, the laccase-negative clone was also capable of consuming at least 60-70% of atrazine within three weeks. Surprisingly, in the corresponding control set (cultivation of laccase-negative clone without atrazine) an unidentified metabolite having a retention time and UV-spectrum similar to those of atrazine was also found. It was concluded that the presence of laccase was not a crucial factor in atrazine consumption by this fungus.

[Fungal decomposition of oat straw during liquid and solid state fermentation]. / Razlozhenie ovsianoi solomy gribami pri zhidkofaznom i tverdofaznom kul'tivirovanii.

White rot fungi (Coriolus hirsutus, Coriolus zonatus, and Cerrena maxima from the collection of the Komarov Botanical Institute of the Russian Academy of Sciences) and filamentous fungi (Mycelia sterilia INBI 2-26 and Trichoderma reesei 6/16) were grown on oat straw-based liquid and solid media, as well as in a bench-scale reactor, either individually or as co-cultures. All fungi grew well on solid agar medium supplemented with powdered oat straw as the sole carbon source. Under these conditions, the mould Trichoderma reesei fully suppressed the growth of all basidiomycetes studied; conversely, Mycelia sterilia neither affected the development of any of the cultures, nor did it show any substantial susceptibility to suppression by their presence. Pure solid cultures of basidiomycetes, as well as the co-culture of Coriolus hirsutus and Cerrena maxima caused a notable bleaching of the oat straw during its consumption. When grown on the surface of oat straw-based liquid medium, the basidiomycetes consumed up to 40% polysaccharides without measurable lignin degradation (a concomitant process). Under these conditions, Mycelia sterilia decomposed no more than 25% lignin in 60 days, but this was observed only after polysaccharide exhaustion and biomass accumulation. In contrast, during solid state straw fermentation, white rot fungi consumed up to 75% cellulose and 55% lignin in 83 days (C. zonarus), whereas the corresponding consumption levels for co-cultures of Mycelia sterilia and Trichoderma reesei equaled 70 and 45%, respectively (total loss of dry weight ranged from 55 to 60%). Carbon dioxide-monitored solid-state fermentation of oat straw by the co-culture of filamentous fungi was successfully performed in an aerated bench-scale reactor.

[Role of structural factor in the kinetics of free-radical oxidation of lipids in the membranes]. / O roli strukturnogo faktora v kinetike svobodnoradikal'nogo okisleniia lipidov v membranakh

Kinetics of free radical oxidation of lipids (formation of primary molecular products - hydroperoxides, secondary products - carbonyl substances and "fluorescent pigments") was studied in various membrane fragments, which were distinctly differentiated by their fatty acid composition. The non-enzymatic catalysis of lipoperoxidation in these systems was initiated by addition of Fe2+ + ascorbic acid. The membrane fragments were isolated from microsomes and mitochondria of rat liver tissue, external segments of frog retina rods, sarcoplasmic reticulum of rabbit and carp skeletal muscles and from microsomes of rabbit brain. In membrane structures the free radical oxidation of lipids developed following the same pattern as the liquid-phase oxidation of alkenes. But in phospholipids of biomembranes the rate of hydroperoxides formation did not correlate with the level of unsaturation of their polyene acyls. The rate of peroxidation of unsaturated fatty acids was distinctly determined by their structural organization in membranes.

[The Ecology Department of the Russian University of the Friendship of Peoples--a scientific, pedagogical and social concept]. / Ekologicheskii fakul'tet Rossiiskogo universiteta druzhby narodov--nauchno-pedagogicheskaia i sotsial'naia kontseptsiia.

The paper is about the foundation of the Environmental Department in the Russian University of Friendship of Peoples with a scientific-educational center of environmental biology and advanced technologies, the faculties of system and industrial environmental biology, human and radiation environmentology with the purpose to boost environmentalism and eco-culture.