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Shubina V.S.,Russian Academy of Sciences | Shatalina Yu.V.,Pushchino State Institute of Natural science
Journal of Applied Spectroscopy | Year: 2013

We have used absorption spectroscopy to study the acid-base and metal-binding properties of two structurally similar flavanones: taxifolin and naringenin. We have determined the acid dissociation constants for taxifolin (pKa1 = 7.10 ± 0.05, pKa2 = 8.60 ± 0.09, pKa3 = 8.59 ± 0.19, pKa4 = 11.82 ± 0.36) and naringenin (pKa1 = 7.05 ± 0.05, pKa2 = 8.85 ± 0.09, pKa3 = 12.01 ± 0.38). The appearance of new absorption bands in the visible wavelength region let us determine the stoichiometric composition of the iron (II) complexes of the flavanones. We show that at pH 5, in solution there is a mixture of complexes between taxifolin and iron (II) ions in stoichiometric ratio 2:1 and 1:2, while at pH 7.4 and pH 9, we detect a 1:1 taxifolin:Fe(II) complex. We established that at these pH values, naringenin forms a 2:1 complex with iron (II) ions. We propose structures for the complexes formed. Comprehensive study of the acid-base properties and the metal-binding capability of the two structurally similar flavanones let us determine the structure-properties relation and the conditions under which antioxidant activity of the polyphenols appears, via chelation of variable-valence metal ions. © 2013 Springer Science+Business Media New York. Source


Murzaeva S.V.,Russian Academy of Sciences | Belova S.P.,Pushchino State Institute of Natural science | Lezhnev E.I.,Pushchino State Institute of Natural science | Luk'yanova L.D.,Russian Academy of Medical Sciences | Mironova G.D.,Pushchino State Institute of Natural science
Bulletin of Experimental Biology and Medicine | Year: 2013

Extralife, a Pentaphylloides fruticos extract, in concentrations of 0.005-10 μg/ml dose-dependently increased H2O2 production in rat heart mitochondria in the presence of respiration substrates. Extralife decreased ATP-induced accumulation of H2O2 related to inhibition of mitochondrial ATP-dependent potassium channel. This effect was observed only at low doses of the adaptogen (0.05-3 μg/ml). High doses of the substance (5-10 μg/ml) did not abolish ATP-dependent production of H2O2 and increased the rate of H2O 2 generation by the mitochondria. We concluded that Extralife in trace concentrations could activate mitochondrial ATP-dependent potassium channel and decrease H2O2 accumulation in the mitochondria. © 2013 Springer Science+Business Media New York. Source


Myasoedova N.M.,Skryabin Institute of Biochemistry and Physiology of Microorganisms | Gasanov N.B.,Pushchino State Institute of Natural science | Chernykh A.M.,Skryabin Institute of Biochemistry and Physiology of Microorganisms | Kolomytseva M.P.,Skryabin Institute of Biochemistry and Physiology of Microorganisms | Golovleva L.A.,Skryabin Institute of Biochemistry and Physiology of Microorganisms
Applied Biochemistry and Microbiology | Year: 2015

The effects of a number of culture medium components, such as peptone, yeast extract, mono- and disaccharides, copper ions, 2,6-dimethylphenol, and polycaproamide fiber, on the laccase activity dynamics in the culture liquid and laccase isoform production by the Lentinus strigosus 1566 fungus were studied. It was demonstrated that some saccharides selectively induced or inhibited the synthesis of different laccase isoforms. Similar action was exerted by copper ions, 2,6-dimethylphenol, and polycaproamide fiber, as well as by their combination. Selective in vivo regulation of the production of certain laccase isoforms by basidial fungi by means of altering the culturing medium composition can be utilised for various biotechnological purposes. © Pleiades Publishing, Inc., 2015. Source


Kirkby N.S.,Queens Medical Research Institute | Kirkby N.S.,Imperial College London | Duthie K.M.,Queens Medical Research Institute | Miller E.,Queens Medical Research Institute | And 6 more authors.
Cardiovascular Research | Year: 2012

Aims The potent vasoconstrictor endothelin-1 (ET-1), acting on the endothelin-A (ETA) receptor, promotes intimal lesion formation following vascular injury. The endothelin-B (ETB) receptor, which mediates nitric oxide release and ET-1 clearance in endothelial cells, may moderate lesion formation, but this is less clear. We used selective ET receptor antagonists and cell-specific deletion to address the hypothesis that ETB receptors in the endothelium inhibit lesion formation following arterial injury. Methods and results Neointimal proliferation was induced by wire or ligation injury to the femoral artery in mice treated with selective ETA (ABT-627) and/or ETB antagonists (A192621). Measurement of lesion formation by optical projection tomography and histology indicated that ETA blockade reduced lesion burden in both models. Although ETB blockade had little effect on ligation injury-induced lesion formation, after wire injury, blockade of the ETB receptor increased lesion burden (184 of vehicle; P < 0.05) and reversed the protective effects of an ETA antagonist. Selective deletion of ETB receptors from the endothelium, however, had no effect on neointimal lesion size. Conclusion These results are consistent with ETB receptor activation playing an important role in limiting neointimal lesion formation following acute vascular injury, but indicate that this protective effect is not mediated by those ETB receptors expressed by endothelial cells. These data support the proposal that selective ETA antagonists may be preferable to mixed ETA/ETB antagonists for targeting the arterial response to injury. Published on behalf of the European Society of Cardiology. All rights reserved. © 2012 The Author. Source


Semenov M.V.,Moscow State University | Stolnikova E.V.,Russian Academy of Sciences | Ananyeva N.D.,Russian Academy of Sciences | Ivashchenko K.V.,Pushchino State Institute of Natural science
Biology Bulletin | Year: 2013

The structure of the microbial community (the fungi-to-bacteria ratio) has been assessed by selective inhibition of the substrate-induced respiration (SIR) using streptomycin sulfate and cycloheximide antibiotics in the gray forest soil of eluvial, transite, transite-accumulative, and accumulative (meadow alluvial) parts of slope landscape on the right bank of the Oka River (near Pushchino, Moscow oblast) which represents an fallow, small-leaved wood, spruce forest, and meadow. The concentrations of bactericide and fungicide were selected experimentally for each landscape parts which provide the greatest SIR inhibition of the soil upon their individual application and in combination. Fungi were established to be predominant in the contribution to the total SIR which was found to be 82-97%. A dependence between the structure of the microbial community and the C/N ratio and pH of the soil was shown. © 2013 Pleiades Publishing, Ltd. Source

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