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Träfflista för sökning "WFRF:(Artemenko V) "

Sökning: WFRF:(Artemenko V)

  • Resultat 1-10 av 13
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1.
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2.
  • Samgina, T. Yu., et al. (författare)
  • Novel natural peptides from Hyla arborea schelkownikowi skin secretion
  • 2010
  • Ingår i: Rapid Communications in Mass Spectrometry. - : John Wiley & Sons, Ltd.. - 0951-4198 .- 1097-0231. ; 24:12, s. 1749-1754
  • Tidskriftsartikel (refereegranskat)abstract
    • Hyla arborea schelkownikowi is one of the leaf frog species inhabiting the southern territories of Russia and the former USSR. This frog species is a member of the Hylidae Rafinesque, 1815 batrachians family. The present study deals with the previously uninvestigated peptidome of the Hyla arborea schelkownikowi skin secretion. Nano-electrospray ionization Fourier transform mass spectrometry (nanoESI-FTMS) of the skin secretion, in the intact form and after acetylation, was selected as the general method of analysis. Electron-capture dissociation (ECD) and collision-induced dissociation (CID) fragmentation were both employed, while de novo sequencing was performed by manual interpretation of the MS data. The suppression of the cyclization of b-ions in the mass spectrometer by the acetylation reaction proved to be very efficient for the de novo sequencing of short peptides. Ten skin peptides were found and all of them, except for bradykinin, had not previously been reported. Six of the peptides belong to the tryptophyllins and related peptides, while three peptides are similar to the aureins.
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3.
  • Petrov, P. P., et al. (författare)
  • Dynamics of wind and the dusty environments in the accreting T Tauri stars RY Tauri and SU Aurigae
  • 2019
  • Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 483:1, s. 132-146
  • Tidskriftsartikel (refereegranskat)abstract
    • Classical T Tauri stars with ages of less than 10 Myr possess accretion discs. Magnetohydrodynamic processes at the boundary between the disc and the stellar magnetosphere control the accretion and ejections gas flows. We carried out a long series of simultaneous spectroscopic and photometric observations of the classical T Tauri stars, RY Tauri and SU Aurigae, with the aim to quantify the accretion and outflow dynamics at time-scales from days to years. It is shown that dust in the disc wind is the main source of photometric variability of these stars. In RY Tau, we observed a new effect: during events of enhanced outflow, the circumstellar extinction becomes lower. The characteristic time of changes in outflow velocity and stellar brightness indicates that the obscuring dust is near the star. The outflow activity in both stars is changing on a time-scale of years. Periods of quiescence in the variability of the H alpha profile were observed during the 2015-2016 period in RY Tau and during the 2016-2017 period in SU Aur. We interpret these findings in the framework of the magnetospheric accretion model, and we discuss how the global stellar magnetic field can influence the long-term variations of the outflow activity.
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4.
  • Samgina, T. Yu, et al. (författare)
  • Investigation of skin secretory peptidome of Rana lessonae frog by mass spectrometry
  • 2011
  • Ingår i: Journal of Analytical Chemistry. - 1061-9348 .- 1608-3199. ; 66:13, s. 1298-1306
  • Tidskriftsartikel (refereegranskat)abstract
    • Amphibian skin secretion represents a cerain scientific interest as a source of biologically active natural peptides. In the present research skin peptidome of wide-spread European frog Rana lessonae (Camerano, 1882) was studied for the first time ever. Peptide sequencing was accomplished with Fourier transform ion cyclotron resonance mass spectrometer in collision-induced and electron capture dissociation modes. A portion of amphibian peptides contains intramolecular C-terminal disulfide cycle which obstructs mass spectrometric sequencing. Two methods were utilized to overcome this difficulty: reduction with dithiotreithol followed by thiol group alkylation and oxidation into sulfonic acid groups with performic acid. Integrated approach employed in the present study allowed the identification of 49 peptides (of 6 to 37 amino acid residues), including 19 novel species.
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5.
  • Samgina, Tatyana Yu., et al. (författare)
  • LC-MS/MS with 2D mass mapping of skin secretions' peptides as a reliable tool for interspecies identification inside Rana esculenta complex
  • 2012
  • Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 34:2, s. 296-302
  • Tidskriftsartikel (refereegranskat)abstract
    • Identification of species constituting Rana esculenta complex represents a certain problem as two parental species Rana ridibunda and Rana lessonae form their hybrid R. esculenta, while external signs and sizes of the members of this complex are intersected. However the composition of skin secretion consisting mainly of peptides is different for the species of the complex. LC-MS/MS is an ideal analytical tool for the quantitative and qualitative analysis of these peptides. The results covering elemental composition of these peptides, their levels in the secretion, as well as their belonging to a certain family of peptides may be visualized by means of 2D mass maps. The proposed approach proved itself to be a perspective tool for the reliable identification of all 3 species constituting R. esculenta complex. Easy distinguishing between the species may be achieved using 2D maps as fingerprints. Besides this approach may be used to study hybridogenesis and mechanisms of hemiclonal transfer of genetic information, when rapid and reliable identification of species involved in the process is required.
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6.
  • Samgina, T. Yu., et al. (författare)
  • Mass spectral study of the skin peptide of brown frog Rana temporaria from Zvenigorod population
  • 2011
  • Ingår i: Journal of Analytical Chemistry. - 1061-9348 .- 1608-3199. ; 66:14, s. 1353-1360
  • Tidskriftsartikel (refereegranskat)abstract
    • Skin secretions of amphibian are an interesting source of biologically active peptides. The present study provides the profile of the skin secretions of the brown frog Rana temporaria from Zvenigorod population (Russia). Sequencing of the skin secretion components has been carried out on an ion cyclotron resonance instrument with electrospray ionization and two methods of fragmentation activation, collisional activation and electron capture. For sequencing of the peptides containing intermolecular C-terminal disulfide cycle two methods of disulfide bond opening have been used: reduction with subsequent alkylation of the free thiol groups and oxidation with performic acid with the formation of sulfo-acid groups. The peptide profile of Rana temporaria studied by a complex mass spectral method has been compared with the data for the frogs of other European populations of this species. For the first time we have revealed ornithokinin-antagonist of the ornithokinin receptor-in skin secretions of amphibians.
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7.
  • Sushko, Iurii, et al. (författare)
  • Applicability Domains for Classification Problems : Benchmarking of Distance to Models for Ames Mutagenicity Set.
  • 2010
  • Ingår i: Journal of chemical information and modeling. - : American Chemical Society (ACS). - 1549-9596 .- 1549-960X. ; 50:12, s. 2094-2111
  • Tidskriftsartikel (refereegranskat)abstract
    • The estimation of accuracy and applicability of QSAR and QSPR models for biological and physicochemical properties represents a critical problem. The developed parameter of "distance to model" (DM) is defined as a metric of similarity between the training and test set compounds that have been subjected to QSAR/QSPR modeling. In our previous work, we demonstrated the utility and optimal performance of DM metrics that have been based on the standard deviation within an ensemble of QSAR models. The current study applies such analysis to 30 QSAR models for the Ames mutagenicity data set that were previously reported within the 2009 QSAR challenge. We demonstrate that the DMs based on an ensemble (consensus) model provide systematically better performance than other DMs. The presented approach identifies 30-60% of compounds having an accuracy of prediction similar to the interlaboratory accuracy of the Ames test, which is estimated to be 90%. Thus, the in silico predictions can be used to halve the cost of experimental measurements by providing a similar prediction accuracy. The developed model has been made publicly available at http://ochem.eu/models/1 .
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8.
  • Valitova, Yu. N., et al. (författare)
  • Binding of sterols affects membrane functioning and sphingolipid composition in wheat roots.
  • 2010
  • Ingår i: Biochemistry (Moscow). - 0006-2979 .- 1608-3040. ; 75:5, s. 554-561
  • Tidskriftsartikel (refereegranskat)abstract
    • The present work was devoted to the exploration of the role of sterols in the functioning of membranes in root cells. Membrane characteristics and composition of the membrane lipids in the roots of wheat (Triticum aestivum L.) seedlings treated with exogenous cholesterol and antibiotic nystatin, which specifically binds with endogenous sterols, were analyzed. Cholesterol caused a fall of membrane potential, acidification of the incubation medium, decrease in potassium leakage of roots, and increase in the level of exogenous superoxide radical. Similarly to cholesterol, the application of nystatin also induced the depolarization of the plasma membrane, but in contrast with cholesterol it was accompanied by alkalinization of the incubation medium and decrease in the level of exogenous superoxide radical. Analysis of membrane lipids showed that following nystatin treatment the total sterol content in roots did not change, while the level of complex sphingolipids represented mainly by glycoceramides became higher. Using mass spectrometry with electrospray ionization (+ESI-MS) for the analysis of the glycoceramide composition, we showed that nystatin induced changes in the ratios of molecular species of glycoceramides. It was suggested that the modification of the sterol component of plasma membrane could influence membrane functioning by changing the sphingolipid composition of lipid rafts.
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9.
  • Galkin, Maxim V., et al. (författare)
  • Hydrogen-free catalytic fractionation of woody biomass
  • 2016
  • Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 9:23, s. 3280-3287
  • Tidskriftsartikel (refereegranskat)abstract
    • The pulping industry could become a biorefinery if the lignin and hemicellulose components of the lignocellulose are valorized. Conversion of lignin into well-defined aromatic chemicals is still a major challenge. Lignin depolymerization reactions often occur in parallel with irreversible condensation reactions of the formed fragments. Here, we describe a strategy that markedly suppresses the undesired condensation pathways and allows to selectively transform lignin into a few aromatic compounds. Notably, applying this strategy to woody biomass at organosolv pulping conditions, the hemicellulose, cellulose, and lignin were separated and in parallel the lignin was transformed into aromatic monomers. In addition, we were able to utilize a part of the lignocellulose as an internal source of hydrogen for the reductive lignin transformations. We hope that the presented methodology will inspire researchers in the field of lignin valorization as well as pulp producers to develop more efficient biomass fractionation processes in the future.
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10.
  • Petrov, P. P., et al. (författare)
  • Another deep dimming of the classical T Tauri star RW Aurigae A
  • 2015
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 577
  • Tidskriftsartikel (refereegranskat)abstract
    • Context. RWAur A is a classical T Tauri star (CTTS) with an unusually rich emission line spectrum. In 2014 the star faded by similar to 3 mag in the V band and went into a long-lasting minimum. In 2010 the star underwent a similar fading, although less pronounced. These events in RW Aur A are very unusual among the CTTS, and have been attributed to occultations by passing dust clouds. Aims. We want to find out if any spectral changes took place after the last fading of RW Aur A with the intention of gathering more information on the occulting body and the cause of the phenomenon. Methods. We collected spectra of the two components of RW Aur. The photometry was performed before and during the minimum. Results. The overall spectral signatures reflecting emission from accretion flows from disk to star did not change after the fading. However, blue-shifted absorption components related to the stellar wind increased in strength in certain resonance lines, and the profiles and strengths but not the fluxes of forbidden lines became drastically different. Conclusions. The extinction through the obscuring cloud is grey indicating the presence of large dust grains. At the same time, there are no traces of related absorbing gas. The cloud occults the star and the interior part of the stellar wind, but not the wind or jet further out. The dimming in 2014 was not accompanied by changes in the accretion flows at the stellar surface. There is evidence that the structure and velocity pattern of the stellar wind did change significantly. The dimmings could be related to passing condensations in a tidally disrupted disk, as proposed earlier, but we also speculate that large dust grains have been stirred up from the inclined disk into the line of sight through the interaction with an enhanced wind.
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