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1.
Chem Biodivers ; 21(8): e202401038, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38849308

RESUMEN

The investigation into the behavior of ficin, bromelain, papain under thermal conditions holds both theoretical and practical significance. The production processes of medicines and cosmetics often involve exposure to high temperatures, particularly during the final product sterilization phase. Hence, it's crucial to identify the "critical" temperatures for each component within the mixture for effective technological regulation. In light of this, the objective of this study was to examine the thermal inactivation, aggregation, and denaturation processes of three papain-like proteases: ficin, bromelain, papain. To achieve this goal, the following experiments were conducted: (1) determination of the quantity of inactivated proteases using enzyme kinetics with BAPNA as a substrate; (2) differential scanning calorimetry (DSC); (3) assessment of protein aggregation using dynamic light scattering (DLS) and spectrophotometric analysis at 280 nm. Our findings suggest that the inactivation of ficin and papain exhibits single decay step which characterized by a rapid decline, then preservation of the same residual activity by enzyme stabilization. Only bromelain shows two steps with different kinetics. The molecular sizes of the active and inactive forms are similar across ficin, bromelain, and papain. Furthermore, the denaturation of these forms occurs at approximately the same rate and is accompanied by protein aggregation.


Asunto(s)
Bromelaínas , Ficaína , Papaína , Desnaturalización Proteica , Papaína/metabolismo , Papaína/química , Desnaturalización Proteica/efectos de los fármacos , Bromelaínas/química , Bromelaínas/metabolismo , Ficaína/química , Ficaína/metabolismo , Cinética , Temperatura , Agregado de Proteínas/efectos de los fármacos , Rastreo Diferencial de Calorimetría , Dispersión Dinámica de Luz
2.
Int J Mol Sci ; 24(15)2023 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-37569860

RESUMEN

The effect of hyperglycemia on the morphology of individual mitochondria and the state of the mitochondrial network in primary mouse lung microvascular endotheliocytes and human dermal fibroblasts has been investigated. The cells were exposed to high (30 mM) and low (5.5 mM) glucose concentrations for 36 h. In primary endotheliocytes, hyperglycemic stress induced a significant increase in the number of mitochondria and a decrease in the interconnectivity value of the mitochondrial network, which was associated with a decrease in the mean size of the mitochondria. Analysis of the mRNA level of the genes of proteins responsible for mitochondrial biogenesis and mitophagy revealed an increase in the expression level of the Ppargc1a, Pink1, and Parkin genes, indicating stimulated mitochondrial turnover in endotheliocytes under high glucose conditions. In primary fibroblasts, hyperglycemia caused a decrease in the number of mitochondria and an increase in their size. As a result, the mitochondria exhibited higher values for elongation. In parallel, the mRNA level of the Ppargc1a and Mfn2 genes in fibroblasts exposed to hyperglycemia was reduced. These findings indicate that high glucose concentrations induced cell-specific morphological rearrangements of individual mitochondria and the mitochondrial network, which may be relevant during mitochondria-targeted drug testing and therapy for hyperglycemic and diabetic conditions.

3.
Int J Mol Sci ; 24(2)2023 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-36674570

RESUMEN

A giant multidomain protein of striated and smooth vertebrate muscles, titin, consists of tandems of immunoglobulin (Ig)- and fibronectin type III (FnIII)-like domains representing ß-sandwiches, as well as of disordered segments. Chicken smooth muscles express several titin isoforms of ~500-1500 kDa. Using various structural-analysis methods, we investigated in vitro nonspecific amyloid aggregation of the high-molecular-weight isoform of chicken smooth-muscle titin (SMTHMW, ~1500 kDa). As confirmed by X-ray diffraction analysis, under near-physiological conditions, the protein formed amorphous amyloid aggregates with a quaternary cross-ß structure within a relatively short time (~60 min). As shown by circular dichroism and Fourier-transform infrared spectroscopy, the quaternary cross-ß structure-unlike other amyloidogenic proteins-formed without changes in the SMTHMW secondary structure. SMTHMW aggregates partially disaggregated upon increasing the ionic strength above the physiological level. Based on the data obtained, it is not the complete protein but its particular domains/segments that are likely involved in the formation of intermolecular interactions during SMTHMW amyloid aggregation. The discovered properties of titin position this protein as an object of interest for studying amyloid aggregation in vitro and expanding our views of the fundamentals of amyloidogenesis.


Asunto(s)
Amiloide , Proteínas Aviares , Pollos , Conectina , Músculo Liso , Animales , Amiloide/metabolismo , Proteínas Amiloidogénicas/metabolismo , Pollos/metabolismo , Conectina/metabolismo , Músculo Liso/metabolismo , Proteínas Aviares/metabolismo
4.
Biochemistry (Mosc) ; 87(7): 605-616, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36154883

RESUMEN

Effect of alisporivir (a mitochondrial permeability transition pore inhibitor) on the development of mitochondrial dysfunction under hyperglycemic conditions in the primary culture of mouse lung endothelial cells was investigated in this work. We demonstrated that hyperglycemia (30 mM glucose for 24 h) leads to the decrease in viability of the pulmonary endotheliocytes, causes mitochondrial dysfunction manifested by the drop in membrane potential and increase in superoxide anion generation as well as facilitates opening of the mitochondrial permeability transition pore (MPT pore). Incubation of endothelial cells with 5 µM alisporivir under hyperglycemic conditions leads to the increase in cell viability, restoration of the membrane potential level and of the MPT pore opening activity to control values. Hyperglycemia causes increased mitophagy in the lung endothelial cells: we observed increase in the degree of colocalization of mitochondria and lysosomes and upregulation of the Parkin gene expression. Alisporivir restores these parameters back to the levels observed in the control cells. Hyperglycemia results in the increase in the expression of the Drp1 gene in endotheliocytes responsible for synthesis of the protein involved in the process of mitochondria fission. Alisporivir does not significantly alter expression of the genes. The paper discusses mechanisms of the effect of alisporivir on mitochondrial dysfunction in murine pulmonary endotheliocytes under conditions of hyperglycemia.


Asunto(s)
Hiperglucemia , Poro de Transición de la Permeabilidad Mitocondrial , Animales , Ciclosporina , Células Endoteliales/metabolismo , Glucosa/metabolismo , Hiperglucemia/metabolismo , Pulmón/metabolismo , Ratones , Mitocondrias/metabolismo , Superóxidos/metabolismo , Ubiquitina-Proteína Ligasas/genética
5.
Molecules ; 27(10)2022 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-35630826

RESUMEN

Self-assembly of organic ions in aqueous solutions is a hot topic at the present time, and substances that are well-soluble in water are usually studied. In this work, aqueous solutions of sodium diclofenac are investigated, which, like most medicinal compounds, is poorly soluble in water. Classical MD modeling of an aqueous solution of diclofenac sodium showed equilibrium between the hydrated anion and the hydrated dimer of the diclofenac anion. The assignment and interpretation of the bands in the UV, NIR, and IR spectra are based on DFT calculations in the discrete-continuum approximation. It has been shown that the combined use of spectroscopic methods in various frequency ranges with classical MD simulations and DFT calculations provides valuable information on the association processes of medical compounds in aqueous solutions. Additionally, such a combined application of experimental and calculation methods allowed us to put forward a hypothesis about the mechanism of the effect of diclofenac sodium in high dilutions on a solution of diclofenac sodium.


Asunto(s)
Diclofenaco , Agua , Aniones , Iones , Soluciones/química , Agua/química
6.
Int J Mol Sci ; 22(21)2021 Nov 04.
Artículo en Inglés | MEDLINE | ID: mdl-34769399

RESUMEN

Despite more than a century of research on the hydration of biomolecules, the hydration of carbohydrates is insufficiently studied. An approach to studying dynamic hydration shells of carbohydrates in aqueous solutions based on terahertz time-domain spectroscopy assay is developed in the current work. Monosaccharides (glucose, galactose, galacturonic acid) and polysaccharides (dextran, amylopectin, polygalacturonic acid) solutions were studied. The contribution of the dissolved carbohydrates was subtracted from the measured dielectric permittivities of aqueous solutions based on the corresponding effective medium models. The obtained dielectric permittivities of the water phase were used to calculate the parameters describing intermolecular relaxation and oscillatory processes in water. It is established that all of the analyzed carbohydrates lead to the increase of the binding degree of water. Hydration shells of monosaccharides are characterized by elevated numbers of hydrogen bonds and their mean energies compared to undisturbed water, as well as by elevated numbers and the lifetime of free water molecules. The axial orientation of the OH(4) group of sugar facilitates a wider distribution of hydrogen bond energies in hydration shells compared to equatorial orientation. The presence of the carboxylic group affects water structure significantly. The hydration of polysaccharides is less apparent than that of monosaccharides, and it depends on the type of glycosidic bonds.


Asunto(s)
Carbohidratos/química , Espectroscopía de Terahertz/métodos , Agua/química , Enlace de Hidrógeno , Modelos Moleculares , Estructura Molecular
7.
Int J Mol Sci ; 22(20)2021 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-34681747

RESUMEN

Hydration plays a fundamental role in DNA structure and functioning. However, the hydration shell has been studied only up to the scale of 10-20 water molecules per nucleotide. In the current work, hydration shells of DNA were studied in a solution by terahertz time-domain spectroscopy. The THz spectra of three DNA solutions (in water, 40 mm MgCl2 and 150 mM KCl) were transformed using an effective medium model to obtain dielectric permittivities of the water phase of solutions. Then, the parameters of two relaxation bands related to bound and free water molecules, as well as to intermolecular oscillations, were calculated. The hydration shells of DNA differ from undisturbed water by the presence of strongly bound water molecules, a higher number of free molecules and an increased number of hydrogen bonds. The presence of 40 mM MgCl2 in the solution almost does not alter the hydration shell parameters. At the same time, 150 mM KCl significantly attenuates all the found effects of hydration. Different effects of salts on hydration cannot be explained by the difference in ionic strength of solutions, they should be attributed to the specific action of Mg2+ and K+ ions. The obtained results significantly expand the existing knowledge about DNA hydration and demonstrate a high potential for using the THz time-domain spectroscopy method.


Asunto(s)
ADN/química , Espectroscopía de Terahertz/métodos , Cationes/química , Enlace de Hidrógeno , Magnesio/química , Cloruro de Magnesio/química , Plásmidos/genética , Potasio/química , Soluciones/química , Agua/química
8.
Int J Mol Sci ; 22(5)2021 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-33800175

RESUMEN

Using a number of optical techniques (interferometry, dynamic light scattering, and spectroscopy), denaturation of hen egg white lysozyme (HEWL) by treatment with a combination of dithiothreitol (DTT) and guanidine hydrochloride (GdnHCl) has been investigated. The denaturing solutions were selected so that protein denaturation occurred with aggregation (Tris-HCl pH = 8.0, 50 mM, DTT 30 mM) or without aggregation (Tris-HCl pH = 8.0, 50 mM, DTT 30 mM, GdnHCl 6 M) and can be evaluated after 60 min of treatment. It has been found that denatured by solution with 6 M GdnHCl lysozyme completely loses its enzymatic activity after 30 min and the size of the protein molecule increases by 1.5 times, from 3.8 nm to 5.7 nm. Denaturation without of GdnHCl led to aggregation with preserving about 50% of its enzymatic activity. Denaturation of HEWL was examined using interferometry. Previously, it has been shown that protein denaturation that occurs without subsequent aggregation leads to an increase in the refractive index (Δn ~ 4.5 × 10-5). This is most likely due to variations in the HEWL-solvent interface area. By applying modern optical techniques conjointly, it has been possible to obtain information on the nature of time-dependent changes that occur inside a protein and its hydration shell as it undergoes denaturation.


Asunto(s)
Pollos , Ditiotreitol/química , Guanidina/química , Muramidasa/química , Agregado de Proteínas , Desplegamiento Proteico , Animales , Espectrofotometría Ultravioleta
9.
Int J Mol Sci ; 22(2)2021 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-33450960

RESUMEN

This work investigated in vitro aggregation and amyloid properties of skeletal myosin binding protein-C (sMyBP-C) interacting in vivo with proteins of thick and thin filaments in the sarcomeric A-disc. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) found a rapid (5-10 min) formation of large (>2 µm) aggregates. sMyBP-C oligomers formed both at the initial 5-10 min and after 16 h of aggregation. Small angle X-ray scattering (SAXS) and DLS revealed sMyBP-C oligomers to consist of 7-10 monomers. TEM and atomic force microscopy (AFM) showed sMyBP-C to form amorphous aggregates (and, to a lesser degree, fibrillar structures) exhibiting no toxicity on cell culture. X-ray diffraction of sMyBP-C aggregates registered reflections attributed to a cross-ß quaternary structure. Circular dichroism (CD) showed the formation of the amyloid-like structure to occur without changes in the sMyBP-C secondary structure. The obtained results indicating a high in vitro aggregability of sMyBP-C are, apparently, a consequence of structural features of the domain organization of proteins of this family. Formation of pathological amyloid or amyloid-like sMyBP-C aggregates in vivo is little probable due to amino-acid sequence low identity (<26%), alternating ordered/disordered regions in the protein molecule, and S-S bonds providing for general stability.


Asunto(s)
Amiloide/química , Amiloide/metabolismo , Proteínas Portadoras/química , Proteínas Portadoras/metabolismo , Agregado de Proteínas , Secuencia de Aminoácidos , Amiloide/ultraestructura , Cromatografía Líquida de Alta Presión , Dicroismo Circular , Dispersión Dinámica de Luz , Técnicas In Vitro , Cinética , Espectrometría de Masas , Modelos Moleculares , Agregación Patológica de Proteínas , Conformación Proteica , Relación Estructura-Actividad , Difracción de Rayos X
10.
Int J Mol Sci ; 21(21)2020 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-33126612

RESUMEN

Long-lived luminescence in the blue region was found to occur in deionized water saturated with atmospheric gases following mechanical shaking. Luminescence intensity decreased exponentially after the cessation of stress. During vigorous mechanical shaking, we observed gas bubbles in solution, and the liquid-gas interface area increased noticeably. At the same time, the concentration of molecular oxygen decreased, which could not be attributed to the water warming up with exposure to mechanical stress. However, deaerated water rapidly became saturated with gases following mechanical stress. The recommendation that cell culture media should be mixed after they are removed from the fridge in order to allow saturation with oxygen is probably misleading. It was shown that gases existed in water both in the form of individual molecules and nanobubbles. Mechanical stress did not influence the number or size of nanobubbles. While gas nanobubbles were absent in freshly prepared deaerated water, they appeared following exposure to mechanical stress. In addition, in mechanically treated gas-saturated water, there was seemingly an equilibrium shift towards the decomposition of carbonic acid to water and carbon dioxide. At the same time, the pH of water tended to increase immediately after mechanical stress. It was demonstrated that reactive oxygen species (ROS) form in gas-saturated water under mechanical stress (30 Hz, amplitude of 5 mm). The relative generation rate of hydrogen peroxide and of the hydroxyl radical was 1 nM/min and 0.5 nM/min, respectively. It was found that with an increase in the frequency of mechanical action (f), the rate of ROS generation increased in proportion to f 2. The major pathways for hydrogen peroxide generation are probably associated with the formation of singlet oxygen and its further reduction, and the alternative pathway is the formation of hydrogen peroxide as a result of hydroxyl radical recombination.


Asunto(s)
Peróxido de Hidrógeno/química , Radical Hidroxilo/química , Especies Reactivas de Oxígeno/química , Oxígeno Singlete/química , Estrés Mecánico , Agua/química
11.
Biochim Biophys Acta Biomembr ; 1860(2): 264-271, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28939382

RESUMEN

The effect of the antimicrobial compound triclosan (5-chloro-2'-(2,4-dichlorophenoxy)phenol) on the permeability of lecithin liposomes and rat liver mitochondria was studied. It was found that triclosan was able to increase nonspecific permeability of liposomes in a dose-dependent manner, which was detected by the release of the fluorescent probe sulforhodamine B (SRB) from vesicles. A partial release of SRB occurs instantly at the moment of triclosan addition, which is followed by a slow leakage of the dye. The triclosan-induced release of SRB from liposomes grew as pH of the medium was decreased from 9.5 to 7.5. As revealed by the laurdan generalized polarization (GP) technique, triclosan increased laurdan GP in lecithin liposomes, indicating a decrease in membrane fluidity. Measurements of GP as a function of fluorescence excitation wavelength gave an ascending line for triclosan-containing liposomes, which can be interpreted as phase heterogeneity of the lipid/triclosan system. Dynamic light scattering experiments also showed that at a high triclosan-to-lipid molar ratio (~0.5), a population of smaller light-scattering particles (~0.4 of the size of liposomes) appear in the system. Experiments with rat liver mitochondria demonstrated that triclosan (10-70µM) induced a high-amplitude cyclosporin А-insensitive swelling of the organelles accompanied the release of cytochrome c. On the basis of the results obtained, possible mechanisms of the toxic effect of triclosan in eukaryotic cells are discussed.


Asunto(s)
Lecitinas/metabolismo , Mitocondrias Hepáticas/efectos de los fármacos , Triclosán/farmacología , Liposomas Unilamelares/metabolismo , Animales , Antiinfecciosos Locales/farmacología , Citocromos c/metabolismo , Concentración de Iones de Hidrógeno , Lecitinas/química , Microscopía Confocal , Microscopía Electrónica de Transmisión , Mitocondrias Hepáticas/metabolismo , Mitocondrias Hepáticas/ultraestructura , Dilatación Mitocondrial/efectos de los fármacos , Permeabilidad/efectos de los fármacos , Ratas Wistar , Rodaminas/metabolismo , Espectrometría de Fluorescencia , Liposomas Unilamelares/química
12.
J Bioenerg Biomembr ; 50(5): 391-401, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30187271

RESUMEN

The paper examines membranotropic Ca2+-dependent effects of ω-hydroxypalmitic acid (HPA), a product of ω-oxidation of fatty acids, on the isolated rat liver mitochondria and artificial membrane systems (liposomes). It was established that in the presence of Ca2+, HPA induced aggregation of liver mitochondria, which was accompanied by the release of cytochrome c from the organelles. It was further demonstrated that the addition of Ca2+ to HPA-containing liposomes induced their aggregation and/or fusion. Ca2+ also caused the release of the fluorescent dye sulforhodamine B from liposomes, indicating their permeabilization. HPA was shown to induce a high-amplitude swelling of Ca2+-loaded mitochondria, to decrease their membrane potential, to induce the release of Ca2+ from the organelles and to result in the oxidation of the mitochondrial NAD(P)H pool. Those effects of HPA were not blocked by the MPT pore inhibitor CsA, but were suppressed by the mitochondrial calcium uniporter inhibitor ruthenium red. The effects of HPA were also observed when Ca2+ was replaced with Sr2+ (but not with Ba2+ or Mg2+). A supposition is made that HPA can induce a Ca2+-dependent aggregation of mitochondria, as well as Ca2+dependent CsA-insensitive permeabilization of the inner mitochondrial membrane - with the subsequent lysis of the organelles.


Asunto(s)
Liposomas/metabolismo , Mitocondrias Hepáticas/metabolismo , Mitocondrias/metabolismo , Ácidos Palmíticos/uso terapéutico , Animales , Ácidos Palmíticos/farmacología , Permeabilidad , Ratas
13.
Biochim Biophys Acta ; 1848(10 Pt A): 2200-5, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26014488

RESUMEN

The effect of surface-potential modulators on palmitate/Ca2+-induced formation of lipid pores was studied in liposomal and inner mitochondrial membranes. Pore formation was monitored by sulforhodamine B release from liposomes and swelling of mitochondria. ζ-potential in liposomes was determined from electrophoretic mobility. Replacement of sucrose as the osmotic agent with KCl decreased negative ζ-potential in liposomes and increased resistance of both mitochondria and liposomes to the pore inducers, palmitic acid, and Ca2+. Micromolar Mg2+ also inhibited palmitate/Ca2+-induced permeabilization of liposomes. The rate of palmitate/Ca2+-induced, cyclosporin A-insensitive swelling of mitochondria increased 22% upon increasing pH from 7.0 to 7.8. At below the critical micelle concentration, the cationic detergent cetyltrimethylammonium bromide (10 µM) and the anionic surfactant sodium dodecylsulfate (10-50 µM) made the ζ-potential less and more negative, respectively, and inhibited and stimulated opening of mitochondrial palmitate/Ca2+-induced lipid pores. Taken together, the findings indicate that surface potential regulates palmitate/Ca2+-induced lipid pore opening.


Asunto(s)
Calcio/farmacología , Permeabilidad de la Membrana Celular/fisiología , Liposomas/química , Membranas Mitocondriales/fisiología , Palmitatos/farmacología , Animales , Calcio/química , Permeabilidad de la Membrana Celular/efectos de los fármacos , Células Cultivadas , Iones , Membranas Mitocondriales/efectos de los fármacos , Palmitatos/química , Porosidad/efectos de los fármacos , Ratas , Ratas Wistar , Electricidad Estática , Propiedades de Superficie/efectos de los fármacos
14.
J Membr Biol ; 249(3): 339-47, 2016 06.
Artículo en Inglés | MEDLINE | ID: mdl-26762382

RESUMEN

The work examines the effect of inhibitors of cytosolic Ca(2+)-dependent and Ca(2+)-independent phospholipases A2 on bilayer lipid membranes. It was established that trifluoroperazine (TFP) and, to a lesser extent, arachidonyl trifluoromethyl ketone (AACOCF3) and palmitoyl trifluoromethyl ketone (PACOCF3) were able to permeabilize artificial lipid membranes (BLM and liposomes). It was shown that AACOCF3 lowered the temperature of phase transition of DMPC liposomes, inducing disordering of the hydrophobic region of lipid bilayer. TFP disordered membranes both in the hydrophobic region and in the region of hydrophilic heads, this being accompanied by changes in the membrane permeability: appearance of a channel-like BLM activity and leakage of sulforhodamine B from liposomes. In contrast to AACOCF3 and TFP, PACOCF3 increased membrane orderliness in the hydrophobic region (heightened the temperature of phase transition of DMPC liposomes) and in the region of lipid heads. The effectiveness of AACOCF3 and PACOCF3 as inductors of BLM and liposome permeabilization was considerably lower comparatively to TFP. As revealed by dynamic light scattering, incorporation of TFP, AACOCF3 and PACOCF3 into the membrane of liposomes resulted in the increase of the average size of particles in the suspension, presumably due to their aggregation or fusion. The paper discusses possible mechanisms of the influence of phospholipase A2 inhibitors on bilayer lipid membranes.


Asunto(s)
Membrana Dobles de Lípidos/química , Inhibidores de Fosfolipasa A2/química , Permeabilidad de la Membrana Celular/efectos de los fármacos , Conductividad Eléctrica , Liposomas/química , Fusión de Membrana , Estructura Molecular , Fosfatidilcolinas/química , Inhibidores de Fosfolipasa A2/farmacología , Fosfolipasas A2/química , Fosfolipasas A2/metabolismo , Rodaminas/metabolismo , Espectrometría de Fluorescencia , Temperatura
15.
Langmuir ; 32(43): 11245-11255, 2016 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-27350310

RESUMEN

Ion-stabilized nanobubbles in bulk aqueous solutions of various electrolytes were investigated. To understand the ion-specific mechanism of nanobubble stabilization, an approach based on the Poisson--Boltzmann equation at the nanobubble interface and in the near-surface layer was developed. It has been shown that the stabilization of nanobubbles is realized by the adsorption of chaotropic anions at the interface, whereas the influence of cosmotropic cations is weak. With increasing temperature, it should be accounted for by blurring the interface due to thermal fluctuations. As a result, the adsorbed state of ions becomes unstable: the nanobubble loses its stability and vanishes. This prediction was proven in our experiments. It turned out that in the case of liquid samples being kept in hermetically sealed ampules, where the phase equilibrium at the liquid-gas interface is fulfilled for any temperature, the volume number density of nanobubbles decreases with increasing temperature and this decrease is irreversible.

16.
Appl Spectrosc ; : 37028241261097, 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-38881287

RESUMEN

This paper describes an approach based on the method of terahertz time-domain spectroscopy, which allows the analysis of dynamical hydration shells of proteins with a thickness of 1-2 nm. Using the example of bovine serum albumin in three conformations, it is shown that the hydration shells of the protein are characterized by increased binding of water molecules in the primary hydration layers, and in more distant areas of hydration, on the contrary, the water structure is somewhat destroyed. The fraction of free or weakly bound molecules, usually observed in the structure of liquid water in hydration shells, become more numerous but its average binding is greater than in undisturbed water. The energy distribution of hydrogen bonds in hydration shells is narrowed compared to undisturbed water. All these manifestations of hydration are most pronounced for the native conformation of the protein. Also, the hydration shells of the native protein are characterized by a smaller number of hydrogen bonds and a tendency to decrease their average energy compared to non-native conformations. The fact of a pronounced peculiarity of the hydration shells of the protein in the native conformation has been noted for different proteins before. However, the methodological approach used in this work for the first time allowed this peculiarity to be described by specific parameters of the intermolecular structure and dynamics of water.

17.
Front Chem ; 12: 1444448, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39119519

RESUMEN

In this work, the terahertz time-domain spectroscopy method analyzed solutions of bovine serum albumin (BSA) in two high concentrations (50 and 334 mg/mL) at three pH values (2.5, 6.5, 8.5) and the same solvents without protein, at 25°C. The spectra of dry BSA were also recorded. For the first time, a method for determining the complex dielectric permittivity of protein molecules in aqueous solutions, without the dielectric contribution of the aqueous phase, is proposed. It is shown that the dielectric permittivity of dissolved and dry BSA (lyophilized, in the native conformation) differ significantly in the terahertz frequency range. These differences are small near 70 cm-1, but they increase greatly with decreasing frequency. It was found that the dielectric losses of protein molecules in solution are close to the dielectric losses of the aqueous environment, which in this frequency range are determined by intermolecular relaxation processes of water. Since dielectric losses are directly related to molecular dynamics, this fact shows that the intramolecular dynamics of the protein completely adjusts to the intermolecular dynamics of the aqueous environment. It also indicates that the native conformation does not determine all the fundamental characteristics of a protein molecule, in particular, it does not determine the dynamics of the protein, which significantly depends on the water environment.

18.
Front Chem ; 12: 1456533, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39391834

RESUMEN

The advancement of experimental methods has provided new information about the structure and structural fluctuations of water. Despite the appearance of numerous models, which aim to describe a wide range of thermodynamic and electrical characteristics of water, there is a deficit in systemic understanding of structuring in aqueous solutions. A particular challenge is the fact that even pure water is a heterogeneous, multicomponent system composed of molecular and supramolecular structures. The possibility of the existence of such structures and their nature are of fundamental importance for various fields of science. However, great difficulties arise in modeling relatively large supramolecular structures (e.g. extended hydration shells), where the bonds between molecules are characterized by low energy. Generally, such structures may be non-equilibrium but relatively long-lived. Evidently, the short times of water microstructure exchanges do not mean short lifetimes of macrostructures, just as the instability of individual parts does not mean the instability of the entire structure. To explain this paradox, we review the data from experimental and theoretical research. Today, only some of the experimental results on the lifetime of water structures have been confirmed by modeling, so there is not a complete theoretical picture of the structure of water yet. We propose a new hierarchical water macrostructure model to resolve the issue of the stability of water structures. In this model, the structure of water is presented as consisting of many hierarchically related levels (the stratification model). The stratification mechanism is associated with symmetry breaking at the formation of the next level, even with minimal changes in the properties of the previous level. Such a hierarchical relationship can determine the unique physico-chemical properties of water systems and, in the future, provide a complete description of them.

19.
Biophys Rev ; 15(5): 833-849, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37974994

RESUMEN

The hydration of biomolecules is one of the fundamental processes underlying the construction of living matter. The formation of the native conformation of most biomolecules is possible only in an aqueous environment. At the same time, not only water affects the structure of biomolecules, but also biomolecules affect the structure of water, forming hydration shells. However, the study of the structure of biomolecules is given much more attention than their hydration shells. A real breakthrough in the study of hydration occurred with the development of the THz spectroscopy method, which showed that the hydration shell of biomolecules is not limited to 1-2 layers of strongly bound water, but also includes more distant areas of hydration with altered molecular dynamics. This review examines the fundamental features of the THz frequency range as a source of information about the structural and dynamic characteristics of water that change during hydration. The applied approaches to the study of hydration shells of biomolecules based on THz spectroscopy are described. The data on the hydration of biomolecules of all main types obtained from the beginning of the application of THz spectroscopy to the present are summarized. The emphasis is placed on the possible participation of extended hydration shells in the realization of the biological functions of biomolecules and at the same time on the insufficient knowledge of their structural and dynamic characteristics.

20.
Biomolecules ; 13(7)2023 06 29.
Artículo en Inglés | MEDLINE | ID: mdl-37509089

RESUMEN

Turpentine oil, owing to the presence of 7-50 terpenes, has analgesic, anti-inflammatory, immunomodulatory, antibacterial, anticoagulant, antioxidant, and antitumor properties, which are important for medical emulsion preparation. The addition of turpentine oil to squalene emulsions can increase their effectiveness, thereby reducing the concentration of expensive and possibly deficient squalene, and increasing its stability and shelf life. In this study, squalene emulsions were obtained by adding various concentrations of turpentine oil via high-pressure homogenization, and the safety and effectiveness of the obtained emulsions were studied in vitro and in vivo. All emulsions showed high safety profiles, regardless of the concentration of turpentine oil used. However, these emulsions exhibited dose-dependent effects in terms of both efficiency and storage stability, and the squalene emulsion with 1.0% turpentine oil had the most pronounced adjuvant and cytokine-stimulating activity as well as the most pronounced stability indicators when stored at room temperature. Thus, it can be concluded that the squalene emulsion with 1% turpentine oil is a stable, monomodal, and reliably safe ultradispersed emulsion and may have pleiotropic effects with pronounced immunopotentiating properties.


Asunto(s)
Escualeno , Trementina , Emulsiones , Escualeno/farmacología , Aceites , Adyuvantes Inmunológicos
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