Чинники ефективності антикризового управління суб'єктами господарювання в економіці України

У статті розглядаються проблеми формування підходів організації антикризового управління суб'єктами господарювання в економіці України. На ґрунті вітчизняного та зарубіжного досвіду й результатів власних досліджень автора запропоновано психологічний тип антикризового менеджера. (The article is devoted to the problems of forming of approaches of organization of anticrisis management by the subjects of menage in the economy of Ukraine. On the base of domestic and foreign experience and results of own researches of author the psychological type of anticrisis manager is offered.

Studies of Early Events of Folding of a Predominately β‑Sheet Protein Using Fluorescence Correlation Spectroscopy and Other Biophysical Methods

The interplay between the early collapse of the unfolded state and the formation of the secondary structure has been the subject of extensive research in protein chemistry. In this study, we used the intestinal fatty acid binding protein (IFABP), a small model protein with predominately β-sheet structure, to study the early events, including the early chain collapse and the formation of the secondary structure. We used a combination of fluorescence correlation spectroscopy and far-UV circular dichroism (CD) to understand how these early processes influence the late folding events like the stabilization of the secondary structure and aggregation. Acid-induced unfolded IFABP was found to collapse in the presence of low concentrations of added salt and aggregate at higher concentrations. Both the formation of the collapsed state and aggregation were conveniently probed by fluorescence correlation spectroscopy, a sensitive fluorescence technique with single-molecule resolution. In contrast, the formation of the secondary structure was monitored by far-UV CD. The results suggested that backbone hydrogen bond formation, not only the overall hydrophobicity of IFABP, may play crucial roles in the early collapse. Two mutant proteins positioned at a crucial nucleating site, namely, G80V and L64G, although being opposite in their overall hydrophobicity, collapsed relatively rapidly compared to the wild-type protein. The interconnection among the early collapse, the formation of the secondary structure, and aggregation was similar for these two mutants. Another mutant, G44V, which was identical in its overall hydrophobicity to G80V but situated in a region distant from the hydrophobic core, was found to be very different from G80V and L64G

Fluorescence Correlation Spectroscopy Study on the Effects of the Shape and Size of a Protein on Its Diffusion Inside a Crowded Environment

Fluorescence correlation spectroscopy (FCS) has been commonly used to study the diffusional and conformational fluctuations of labeled molecules at single-molecule resolution. Here, we explored the applications of FCS inside a polyacrylamide gel to study the effects of molecular weight and molecular shape in a crowded environment. To understand the effect of molecular weight, we carried out FCS experiments with four model systems of different molecular weights in the presence of varying concentrations of acrylamide. The correlation curves were fit adequately using a model containing two diffusing components: one representing unhindered diffusion and one representing slow hindered diffusion in the gel phase. A large number of measurements carried out at different randomly chosen spots on a gel were used to determine the most probable diffusion time values using Gaussian distribution analysis. The variation of the diffusivity with the molecular weight of the model systems could be represented well using the effective medium model. This model assumes a combination of hydrodynamic and steric effects on solute diffusivity. To study the effects of solute shape, FCS experiments were carried inside a urea gradient gel to probe the urea-induced unfolding transition of Alexa488Maleimide-labeled bovine serum albumin. We showed that the scaling behavior, relating the hydrodynamic radius and the number of amino acids, changes inside an acrylamide gel for both folded and unfolded proteins. We showed further that crowding induced by a polyacrylamide gel increases the resolution of measuring the difference in hydrodynamic radii between the unfolded and folded states

A Facile Synthesis of PEG-Coated Magnetite (Fe₃O₄) Nanoparticles and Their Prevention of the Reduction of Cytochrome C

We report here a facile and green synthetic approach to prepare magnetite (Fe₃O₄) nanoparticles (NPs) with magnetic core and polyethylene glycol (PEG) surface coating. The interaction of the bare and PEG-coated Fe₃O₄ NPs with cytochrome c (cyt c, an important protein with direct role in the electron transfer chain) is also reported in this study. With ultrasonication as the only peptization method and water as the synthesis medium, this method is easy, fast, and environmentally benign. The PEG coated NPs are highly water dispersible and stable. The bare NPs have considerable magnetism at room temperature; surface modification by PEG has resulted in softening the magnetization. This approach can very well be applicable to prepare biocompatible, surface-modified soft magnetic materials, which may offer enormous utility in the field of biomedical research. Detailed characterizations including XRD, FTIR, TG/DTA, TEM, and VSM of the PEG-coated Fe₃O₄ NPs were carried out in order to ensure the future applicability of this method. Although the interaction of bare NPs with cyt c shows reduction of the protein, efficient surface modification by PEG prevents its reduction

Unfolding transitions of WT and cysteine mutants of Viperin monitored by far- UV CD.

<p>Urea induced unfolding of the WT (black), the triple mutant (red), C83A mutant (blue), C87A mutant (dark green), and C90A mutant (magenta) of Viperin. The ellipticity measured at 223 nm is plotted against urea concentration. The data for WT and the cysteine mutants are fit to equation 1 assuming two state unfolding transitions. The experiments have been carried out in 20 mM phosphate buffer at pH 7.5.</p

Far-UV circular dichroism spectra of WT and cysteine mutants of Viperin.

<p>Far-UV CD spectra of the WT Viperin (____), the triple cysteine mutant (-.-.-.), C83A mutant (_ . . . _), C87A mutant (- - - -), C90A mutant (. . . .). The CD experiments have been carried out in 20 mM sodium phosphate buffer at ph7.5.</p

Fluorescence spectra of WT and cysteine mutants of Viperin in folded and unfolded condition.

<p>Fluorescence emission spectra of (a) the WT Viperin, (b) the triple mutant (c) C83A mutant, (d) C87A mutant and (e) C90A mutant (f) NATA in the absence (void circle) and presence (closed circle) of 10 M urea. Fluorescence experiments have been carried out in 20 mm phosphate buffer at pH 7.5. A red shift in the emission spectra is shown by a double headed arrow for the WT protein.</p

Thermodynamic parameters of the equilibrium unfolding transitions of WT and cysteine mutants of Viperin.

<p>Thermodynamic parameters of the equilibrium unfolding transitions of WT and cysteine mutants of Viperin.</p

UV-visible absorption spectra of WT and cysteine mutants of Viperin.

<p>UV-visible absorption spectra of the WT Viperin (black), the triple cysteine mutant (cyan), C83A mutant (red), C87A mutant (blue), and C90A mutant (dark green). The experiments are performed in 20 mM sodium phosphate buffer at ph7.5. The WT protein exhibits two peaks at 325 nm and 410 nm (shown by arrows) which are characteristic of Fe-S cluster. They are found to be absent in the case of cysteine mutants.</p

Comparative Study of Toluidine Blue O and Methylene Blue Binding to Lysozyme and Their Inhibitory Effects on Protein Aggregation

A comparative binding interaction of toluidine blue O (TBO) and methylene blue (MB) with lysozyme was investigated by multifaceted biophysical approaches as well as from the aspects of in silico biophysics. The bindings were static, and it occurred via ground-state complex formation as confirmed from time-resolved fluorescence experiments. From steady-state fluorescence and anisotropy, binding constants were calculated, and it was found that TBO binds more effectively than MB. Synchronous fluorescence spectra revealed that binding of dyes to lysozyme causes polarity changes around the tryptophan (Trp) moiety, most likely at Trp 62 and 63. Calorimetric titration also depicts the higher binding affinity of TBO over MB, and the interactions were exothermic and entropy-driven. In silico studies revealed the potential binding pockets in lysozyme and the participation of residues Trp 62 and 63 in ligand binding. Furthermore, calculations of thermodynamic parameters from the theoretical docking studies were in compliance with experimental observations. Moreover, an inhibitory effect of these dyes to lysozyme fibrillogenesis was examined, and the morphology of the formed fibril was scanned by atomic force microscopy imaging. TBO was observed to exhibit higher potential in inhibiting the fibrillogenesis than MB, and this phenomenon stands out as a promising antiamyloid therapeutic strategy