Репозиторий Университета

© 2020 This study demonstrates an ultra-sensitive material towards 1-butylamine. The material is composed of 4 wt% Au nanoparticles decorated on MoO3 nanobelts, which are prepared via the hydrothermal method and in-situ reduction. The related characterizations reveal that the nanobelts are highly crystallized layer structures with a width of ~ 200 nm, a thickness of 40 nm and a length of several micrometers. The Au/MoO3 composites exhibit ultra-high sensing response (~300) towards 100 ppm of 1-butylamine at the working temperature of 240 °C. Even without Au decoration, the pristine MoO3 nanobelts offer the response as high as ~ 90 toward the same concentration of 1-butylamine at the temperature of 340 °C, much higher than the existing materials. More importantly, the proposal materials have excellent selectivity towards 1-butylamine, which offers the possibility for practical use. The excellent sensing performance is attributed to the unique sensing mechanism of the layered MoO3 nanobelts via catalytic reaction between 1-butylamine and the lattice oxygen of MoO3. Besides, Au decoration enables to enhance the adsorption of 1-butylamine and facilitate the catalytic sensing process, resulting in further increase in sensing response and selectivity of 1-butylamine. This study may shield light on a promising high-performance gas sensing materials to detect amines in practical application.

© 2019 American Chemical Society. Various agents, including drugs as well as nonmolecular stimuli, induce alterations in the physicochemical properties of proteins in cell lysates, living cells, and organisms. These alterations can be probed by applying a stability- and solubility-modifying factor, such as elevated temperature, to a varying degree. As a second dimension of variation, drug concentration or agent intensity/concentration can be used. Compared to standard approaches where curves are fitted to protein solubility data acquired at different temperatures and drug concentrations, Proteome Integral Solubility Alteration (PISA) assay increases the analysis throughput by 1 to 2 orders of magnitude for an unlimited number of factor variation points in such a scheme. The consumption of the compound and biological material decreases in PISA by the same factor. We envision widespread use of the PISA approach in chemical biology and drug development.

© 2019 Wiley-Blackwell. All rights reserved. Laccases are enzymes that catalyze the oxidation of a wide range of organic and inorganic substrates accompanied by the reduction of molecular oxygen to water. Here, a subatomic resolution X-ray crystallographic study of the mechanism of inhibition of the laccase from the basidiomycete fungus Steccherinum murashkinskyi by chloride and fluoride ions is presented. Three series of X-ray diffraction data sets were collected with increasing doses of absorbed X-ray radiation from a native S. murashkinskyi laccase crystal and from crystals of complexes of the laccase with chloride and fluoride ions. The data for the native laccase crystal confirmed the previously deduced enzymatic mechanism of molecular oxygen reduction. The structures of the complexes allowed the localization of chloride and fluoride ions in the channel near the T2 copper ion. These ions replace the oxygen ligand of the T2 copper ion in this channel and can play the role of this ligand in the enzymatic reaction. As follows from analysis of the structures from the increasing dose series, the inhibition of laccases by chloride and fluoride anions can be explained by the fact that the binding of these negatively charged ions at the position of the oxygen ligand of the T2 copper ion impedes the reduction of the T2 copper ion.

© 2013-2018 Federal Scientific Center for Medical and Preventive Health Risk Management Technologies. Yessotoxin (YTX) is a polyether. There are more than 90 known derivatives of yessotoxin. YTX was excluded from diarrhea toxins group as it, unlike okadaic acid, doesn't cause diarrhea. YTX chemical structure is similar to that of brevetoxins and ciguatoxins that influence functioning of calcium-sodium pump and trans-membrane ion channels. So, YTX can exert influence on functioning of all the organs and systems in a body. YTX is known to promote apoptosis in the cerebral tissues. Average lethal dose LD50 for YTX and its analogues varied from 100 μg/kg to 500-750 μg/kg; the figures were obtained in various experiments performed on mice. Safe YTX level for acute impact (acute reference dose) amounts to 25 μM/kg of body weight. Nowadays toxicity parameters for YTX and some of its analogues are determined; its basic action mechanisms and a role it plays in promoting apoptosis are well-known. In spite of more and more data on biological effects produced by YTX on a warm-blooded organism, experts are still unable to describe its action mechanisms precisely. Our research goal was to examine YTX toxicity in experiments in vivo in doses that were lower than the detected acute reference dose. The experiment was performed on 72 male Wistar rats with initial body weight being equal to 100±10 g. Animals were given dry balanced feedstuffproduced by "Laboratortakorm" LLC (Russia) and had free access to it. We used YTX preparation produced by "National Research Council Canada" (Canada) in our experiment; the preparation was a methanol solution (YTX content was equal to 4.3 μmol). We determined mass of internal organs, biochemical and hematological blood parameters, apoptosis of brain cells, malonic dialdehyde level in the brain and reduced glutathione in the liver. We showed that YTX doses (2μM/kg, 8μM/kg and 12μM/kg) lower than ARfD=2μM/kg can exert toxic impacts on a warm-blooded organism. The obtain data prove it is necessary to additionally assess risks of an increase in maximum permissible YTX contents in shellfish from 1 mg/kg to 3.75 mg/kg.