Alexander Pogorelov

• Prof., Sci.Dr., Ph.D.
• Principal Investigator at Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences

A method of extraction of quercetin from a plant cell based on the combined action of ultrasound and a metastable fraction of an aqueous solution is proposed. This treatment leads to more efficient release of the cytoplasmic component due to etching and/or mechanical destruction of the plant cell envelope. The oxidized fraction of the solution has...

Ensuring quality of food products and raw materials is one of the central issues at all stages of their life cycle and priority area of every state policy. The aim of the work is to provide systematic improvement quality and microbiological safety (Escherichia coli, Staphylococcus aureus, Listeria monocytogenes) of food by incorporating highly effe...

The method for the extraction of quercetin from plant cells with the use of ultrasound in combination with metastable fraction from aqueous solution is proposed. The procedure enabled more efficient isolation of the cytoplasmic part due to etching and/or mechanical destruction of the cell membrane. The oxidized water fraction has the most pronounce...

The present study was conducted to investigate the effect of complex amylolytic preparations on green buckwheat starch in the environment of oxidized and reduced fractions of electrochemically activated solutions. The novelty of the work lies in the study of the effect of catholyte and anolyte obtained from tap water on the accumulation of reducing...

In this work, the hydrolysis of starch in an enzyme solution was studied, where softened water or fractions of a metastable electrochemically activated aqueous solution (ECAS) were used as a solvent. Extracts obtained after hydrolysis of food starch grains were analyzed using optical density spectrometry of the sample and micro-weighing with a quar...

Metastable electrochemically-activated water solutions possess unique properties that make it possible to modify food emulsions. This comparative analysis featured the stability of model oil-in-water emulsions with anolyte or catholyte as a dispersion medium, as well as the physical and morphometric profile of the emulsion system. The research invo...

The determination of changes in the properties of polysaccharides in electrochemically activated water solution were carried out by means of UV-Vis spectrophotometry, time-of-flight secondary ion mass spectrometry and scanning electron microscopy. It was shown how the properties of samples analyzed (agar, modified starch, edible starch) changed dep...

Introduction. Electrochemical activation of water controls the physicochemical parameters of aquatic food environment without any reagents. Electrolyzed water affects the properties of macronutrient solutions. The present research studied the effect of anodic and cathodic fractions of electrochemically activated water on protein molecules and their...

Electrochemical activation of water (ECAW) is a topical method of reagent-free regulation of physicochemical parameters of aquatic food environments. The properties of solutions of macronutrients based in ECAW may differ from similar solutions on untreated water. In this work, the regularities of the interaction of the anodic and cathodic fractions...

A nanocarrier was obtained by coating the natural clinoptilolite particle surface with a phosphatidylcholine layer. The shell effective size does not exceed the thickness of the phospholipid molecular layer, which was confirmed by UV spectrometry and molecular mass spectrometry. The hydrodynamic diameter of the formulated nanocarrier, which was det...

One of the directions for improving existing and creating new technologies for bakery products can be associated with the regulation of dough making processes through the use of electrochemically activated (ECA) water during kneading. By the ECA water method in the zone of one of the electrodes (anode or cathode) of the diaphragm reactor, respectiv...

Electrochemically activated water has a high physicochemical and biological activity. It interacts with food ingredients and affects the baking process in a different way than untreated water. The research objective was to study the effect of the anodic and cathodic fractions of electrochemically activated water on the quality indicators of wheat f...

The change in the redox potential of water and solutions of bovine serum albumin and gelatin in electrochemically activated water with a reduced value of the redox potential obtained in the cathode chamber of a diaphragm electrochemical reactor is considered. The dependence of the relaxation rate of a protein solution in electrochemically activated...

The paper experimentally investigates and theoretically substantiates a reagent-free electrochemical technology for fresh natural water purification, which simulates oxidative, reduction and filtration processes of water purification for the needs of agriculture. The use of the latest advances in the design of flow-through electrochemical diaphragm...

Using a non-invasive approach, quantitative laser scanning microtomography (QLSM), the morphology of human oocyte was studied layer-by-layer. Then, the cell volume was computed based on 3D reconstruction of a stack of optical sections obtained by QLSM. The integrity of oocyte membrane after cryopreservation was assessed by measuring the changes in...

For in vitro fertilization technology, the quality of oocytes has a direct impact on the egg fertilization and developmental competence of early embryo. The morphological criteria are used for the estimation of oocyte quality before its fertilization in vitro. To date, only one method is known to determine the maturity of oocyte. This is the routin...

A technology for obtaining nanoparticles of natural clinoptilolite, a mineral from the zeolite family, under laboratory conditions has been developed. The size of zeolite particles was determined by scanning electron microscopy, and the size of nanocapsules was determined by dynamic light scattering. A method for applying a layer of alcohol-soluble...

Microporous materials can provide interesting tools for different goals from bioimaging to the delivery of bioactive molecules. In this study, the procedure based on cryo-approaches was designed to formulate the nanoparticles of natural clinoptilolite from the Zeolites mineral family. Applying scanning electron microscopy, clinoptilolite samples we...

Currently two techniques exist for 3D reconstruction of biological samples by time-of-flight secondary ion mass spectrometry (ToF-SIMS). The first, based on microtomy and combining of successive section images, is successfully applied for tissues, while the second, based on sputter depth profiling, is widely used for cells. In the present work, we...

This work aimed to study the fine structure of bacterial films grown on the inner tuber surface of flow reactor. Applying scanning electron microscopy (SEM) approaches, the detailed biofilm relief was visualized. The action of electrochemically reduced water (ERW) on the biofilm ultrastructure generated by the plankton form of E.coli and/or lacto b...

The aim of this work was to study the fine structure of bacterial films grown on the inner tube surface of a flow reactor. Using the scanning electron microscopy (SEM) approaches, the detailed biofilm relief was visualized. The action of electrochemically reduced water (ERW) on the biofilm ultrastructure generated by the plankton form of E. coli an...

The structure of bacterial film formed at the inner surface of the recirculation reactor tube, is studied. The surface relief of the biofilm was visualized by scanning electron microscopy. The effect of electrochemically activated water solution on the film formed from planktonic lactobacteria or E. coli was studied. Treatment with electrochemicall...

The technique for the preparation of biological tissue sections developed for Electron Probe Microanalysis has been adapted for ToF-SIMS analysis of mouse GV stage oocytes. GV-oocyte sample preparation involves the following steps: plunge freezing, freeze drying, impregnation in an embedding medium, and section cutting. Molecule-specific images of...

It has been shown that Dulbecco’s incubation medium prepared with electrochemically reduced water compensates for oxidative stress induced by hydrogen peroxide addition (H2O2, 0.2 mM) to the incubation medium. The incubation medium modified in this way does not affect the H2O2 induced apoptosis in an early mouse embryo. The embryonic cell in the ex...

Statements of significance: We found that cardiomyocytes grown on electrospun polymer nanofibers often create a striking "sheath" structure, enveloping fiber with the formation of a very narrow (∼22 nm) membrane gap leading from the fiber to the extracellular space. This wrapping makes the entire fiber surface available for cell attachment. This f...

The structural organization of the biological material in the nucleoli (Nucleolus-Like Bodies (NLBs)) in mouse GV oocytes has been studied with atomic force microscopy (AFM), scanning electron microscopy (SEM), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Experimental samples are prepared by quick plunge freezing, followed by free...

Analysis of the element composition of oviduct and uterine fluid in mammals showed high potassium concentrations in the early embryo microenvironment in vivo. The results of early embryogenesis of mammals in vitro in the presence of high potassium concentrations are discussed. The data are summarized in accordance with the conditions of experimenta...

The 2D-molecular thin film analysis protocol for fully grown mice oocytes is described using an innovative approach. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and optical microscopy imaging were applied to the same mice oocyte section on the same sample holder. A fre...

This paper updates our knowledge on quantitative laser scanning microscopy and summarizes the capabilities of this method as applied to cytometry and analysis of cell structure of the mouse early embryo and the oocyte. This method requires a stack of optical sections obtained as Z-series with subsequent 3D reconstruction. This approach was used for...

The given paper summarizes the data on the early mammalian embryo development in culture media containing low oxygen concentration. Experimental results on in vitro modeling the hypoxia for preimplantation development are reviewed. Hypoxic conditions were shown to be available in the female reproductive tract of different mammalian species. The est...

Regulatory volume decrease in response to hypotonic stress is typical of the oocytes and early mouse embryos. Changes in the kinetics of osmotic reaction can be used as a marker of the modulating effect of the incubation medium on transmembrane transport in embryonic cells. Quantitative laser scanning microtomography (QLSM) was used to measure oocy...

The inner surface of the drainage catheter used in surgical interventions for biliary system pathologies was examined by scanning electron microscopy. Microfl ora in the catheter lumen refl ects etiological characteristics of the pathological process and helps to predict possible complications. The developed scanning electron microscopy imaging tec...

Electron probe microanalysis was applied to study the kinetics of changes in potassium and sodium concentration in muscle cells of isolated heart from Wistar rat during experimental ischemia. Hypoxic perfusion without glucose was shown to evoke the potassium deficiency and sodium accumulation in cardiac myocells. Short-term action (10 min) of strop...

Using quantitative laser-scanning microtomography (QLSM), the response of mature mouse oocytes to hypotonic stress was investigated. The response exhibited the following features: (1) oocytes were capable of regulatory volume decrease (RVD); (2) unlike zygote and two-cell embryo, the oocyte volume recovery was not complete even by 120 min; (3) mill...

Specific features of the quantitative laser microtomography of biological samples are discussed. The method exhibits the main advantages of a confocal microscope (rapid measurement of a stack of parallel optical cross sections and accurate displacement of an object along the optical axis). A relatively high contrast is reached owing to the superpos...

Ice slices of root tissues were investigated by X-ray microanalysis. It is shown that the cytoplasm of the meristematic and differentiated cells of potassium dificiest roots maintains a high potassium level. The vacuoles of various root cells loose more K and accumulate more Na and Mg than does the cytoplasm.

The aim of the investigation was to estimate the availability of new biomedical technologies to identify bacterial biofilms and evaluate them on a staphylococcal biofilm model. Materials and Methods. We studied staphylococcal biofilms by mass spectrometry, laser scanning (confocal) microscopy, scanning electron microscopy, enzymatic and oxidative...

The surface of wound dressing Biocol was studied by scanning electron microscopy. This composite system consists of latex matrix with incorporated water-soluble polysaccharide. The peculiarities of the surface are important for manufacturing of the dressing and for modification of its surface upon contact with fluids, e.g. during de novo tissue rec...

In the given investigation contents of potassium and its physiological analog, rubidium, are determined in cardiomyocyte. Applying Electron Probe Microanalysis (EPMA), cytoplasmic concentrations of elements (K, Rb) are measured. The data obtained exhibit that for initial acute ischemia phase the active transport is involved in the uptake of rubidiu...

Mouse single-cell embryos exhibit robust Regulatory Volume Decrease (RVD). In what manner the very early mammalian embryo following zygote stage is appreciably altered by the anisotonic extracellular solution is, as yet, totally unclear. Little attention was paid to this direction since there was no way to determine the blastomere volume. This work...

Osmolarity of Dulbecco's medium at which the volume of two-cell mouse embryo remained similar to that of intact embryo was determined. The method is based on comparison of kinetic curves describing the volume of embryonic cell in solutions of different osmolarity. The blastomere volume was measured by quantitative laser microtomography after fixed...

Electron probe microanalysis was applied to determine cytoplasmic elemental (K, Na, Cl) concentrations in cardiac cells of the rat (Wistar). Potassium, sodium and chlorine contents were measured in papillary muscle myocytes of the rat heart perfused by the Langendorff procedure. Ischemic depletion was created by perfusion with deeply deoxygenated T...

We performed qualitative comparison of freeze drying and chemical drying as methods of preparing 3D wet specimens for scanning electron microscopy. Human fibroblasts immobilized in collagen gel were used as a model system. Specimens fixed with glutaraldehyde were frozen in liquid nitrogen and freeze-dried at low temperature in high vacuum. In paral...

Electron probe microanalysis was applied to determine cytoplasmic elemental (K, Na, Cl) concentrations in cardiac cells of the rat (Wistar). Potassium, sodium and chlorine contents were measured in papillary muscle myocytes of the rat heart perfused by the Langendorff's procedure. Ischemic depletion was created by perfusion with deeply deoxygenated...

The blastomer volume was measured by three-dimensional (3D) reconstruction of a series of successive optical sections of the early mouse embryo. Changes in cell volume during osmotic shock were studied. Incubation of a two-cell embryo in Dulbecco's medium induced slow shrinkage of the embryonic cells followed by recovery of its initial volume. A re...

The direct method of volumetric parameters’ measurement of early mammal embryo was developed. The sample preparation was based on embryo cryofixation followed by laser scanning microscopy. Digital image processing and three dimensional reconstruction of embryos was performed with standard graphic software. The availability of a developed technique...

The impact of the osmotic component of the incubation medium for the volume of mouse early embryonic cell was studied by laser scanning microscopy. Common Dulbecco's medium caused a prolonged hyperosmotic effect. Adaptive phase of regulatory compensation for the osmotic shock was observed under hypotonic conditions. From these data, water permeabil...

Osmotic adaptation in a mouse embryo blastomere has been studied by direct measurement of the cell volume using microtomography Osmotic adaptation in a mouse embryo blastomere has been studied by direct measurement of the cell volume using microtomography (laser scanning microscopy followed by quantitative 3D reconstruction). Embryo cells subjected...

Osmotic adaptation in a blastomere of mouse embryo has been studied by the direct measurement of the cell volume using laser scanning microscopy microtomography followed by quantitative 3D reconstruction. Embryonic cells subjected to hypotonic shock first swelled and then returned to the initial size. At the beginning of osmotic stress, the swellin...

The cytoplasmic concentrations of elements (K, P) in the cytoplasm of rat (Wistar) cardiomyocytes have been determined by electron probe microanalysis. The intracellular content of potassium and phosphorus was determined in early organogenesis and in unfertilized animals. A decrease in the cytoplasmic concentration of phosphorus and an increase in...

The cell volume alteration participates in a wide variety of cellular functions that may interfere with intra-cellular homeostasis. The most adequate approach of estimation of the volume changes induced by osmotic misbalance, alteration in shape and size due to the action shape forming substances, etc., is the direct measurement of volumetric param...

The concentrations of potassium and phosphorus in the cardiomyocyte cytoplasm of the Wistar rat were measured by means of electron probe microanalysis. Pregnancy was accompanied by a decrease in cytoplasmic phosphorus concentration and an increase in cytoplasmic potassium concentration. Acute hypoxia modified the concentrations of these elements in...

Cytoplasmic Na/K imbalance induced by cytotoxic substances (ethylene glycol and cytochalasin B) was studied. Incubation in Dulbecco's medium with these cytotoxins caused changes in K and Na concentrations in the mouse two-cell embryo blastomer. The effects of both substances resulted in a drop of Na content in the embryonic cell. Washing from cytoc...

Administration of substrates of energy metabolism in combination with hypoxen (sulfur-containing oligoquinone) promoted the increase in blood lactate concentration during maximum exercise, accelerated lactate utilization, and reduced the lactate/pyruvate ratio during recovery. The in vivo effects are in line with hypoxen capacity to accelerate in v...

Menopausal transition is often accompanied by a variety of adverse pathological symptoms, currently treated with hormone replacement therapy, which is associated with a number of health risks. This report investigated the role of a food supplement--a composition of energy-exchange metabolites, with succinate as the main component--for treating meno...

Age-related changes in the cardiac function in animals are accompanied and/or caused by a decrease in the action potential plateau [1]. This parameter changes with age and depends on the potassium current in the cardiomyocyte [2]. As a result, one should expect a change in the potassium balance in the cell, which would affect key molecular-genetic...

Changes in the cell volume play an important role in regulation of key cellular functions, including metabolism [1], protein synthesis [1], gene expression [2] and cell death [3]. The early embryo membrane is highly permeable for water, that makes the cell very sensitive to osmotic shock [4]. Qualitative relationships between osmotic characteristic...

Intracellular concentrations of potassium and sodium in two-cell mouse embryos in G1/S phase after exposure to vitrification solutions containing vitrificant agents (VFAs) ethane-1,2-diol (ethylene glycol, EG), propane-1,2-diol (propylene glycol, PG), or dimethyl sulfoxide (DMSO), and sucrose (S) after incubation in Dulbecco solution were measured...

In the companion paper (CryoLetters, 2007, 28:403-408), we reported effects of exposure of two-cell mouse embryos to vitrification solutions containing different vitrificants (EG, PG and DMSO) on the intracellular potassium and sodium content. We also compared exposure of 30% (v:v) ethylene glycol for 1.5 min to the similar experiments with 3-min e...

Changes in intracellular elemental (Na, K) concentrations caused by cytochalasin B were measured by electron probe microanalysis. Cytochalasin B is applied to transfer somatic cell nuclei into early embryo cells. This chemical causes a cytoskeleton rearrangement that may activate potassium channels, which, in turn, results in a cytoplasmic Na+/K+ i...

The 3D structure of the heart tissue of Wistar rats from different age groups has been reconstructed by light microscopy of consecutive series of semithin sections. At the histological resolution level, connective tissue segments in the myocardium of aged (18 months) animals were found, while in the myocardium of young (2 months) animals no connect...

This work was performed to study changes in intracellular elemental (Na/K) concentrations caused by Cytochalasin B in two-cell mouse embryo using Electron Probe Microanalysis. The presence of Cytochalasin B is required to transfer a somatic cell nuclear into an early embryo cell. The direct effect of this chemical is cytoskeleton transformation, wh...

Serial semithin optical sections were used for 3D reconstruction of rat ventricular tissue. At histological resolution, older animals (18 months) were found to have regions of fibrous connective tissue not observed in young animals (2 months). The 3D data were used in mathematical modeling of excitation wave propagation in a medium containing such...

Age-related changes in the concentrations of the main cations potassium and sodium in the cardiac muscle cell of Wistar rats were studied. The cytoplasmic concentrations of potassium and sodium were measured by electron probe microanalysis. The results obtained showed differences both in concentrations of the cations between young and old reference...

Age-related changes in the content of the major cellular cations of potassium and sodium in heart muscle cells of Wistar rats have been studied. The cytoplasmic concentration of potassium and sodium was determined by the electron probe microanalysis. The results revealed differences in both the concentration of the elements in young and old control...

Electron probe microanalysis is a method for evaluation of concentrations of elements at the subcellular level, effective in studies of an individual cell in culture or suspension. Intracellular concentrations of cytoplasmic ions (K+, Na+, Cl-) most rapidly and markedly reacting to changes is an adequate criterion for evaluating the traumatism of m...

Intracellular concentration of potassium and sodium in two-cell mouse embryos in G1/S phase after exposition to vitrification solutions containing ethylene glycol (EG) and sucrose or after incubation in Dulbecco solution were measured by electron probe microanalysis (EPMA). The embryos at room temperature were treated in 10 percent EG for 10 min, t...

The mean potassium and sodium concentrations and distribution of potassium in clonogenic culture of human neural stem cells (neurosphere) were estimated by means of electron probe microanalysis. High sodium concentration was typical of undifferentiated cells. Potassium was irregularly distributed in the test structure. Our results confirm published...

Oocytes, as well as one- and two-cell embryos, of the mouse are characterized by a low intracellular concentration of potassium [1‐2]. This may be accounted for by either a low Na/K-ATPase activity or an intense passive transport of the ä + cation from embryonic cells. Cell division cycles in early embryos have been demonstrated to be synchronized...

Intracellular concentrations of potassium and phosphorus were determined by Electron Probe Microanalysis in mouse mature oocytes and zygotes. The oocytes were characterized by insignificant variations in the concentrations of these elements in the cytoplasm: 60 4 and 103 6 mM, respectively. In zygotes, on the contrary, significant variations were o...

Intracellular concentrations of potassium and phosphorus were determined by Electron Probe Microanalysis in mouse mature oocytes and zygotes. The oocytes were characterized by insignificant variations in the concentrations of these elements in the cytoplasm: 60 +/- 4 and 103 +/- 6 mM, respectively. In zygotes, on the contrary, significant variation...

Method of 3-D reconstruction approaches for early mouse embryo in preimplantation stages was modified. The developed technique is based on application of light microscopy of serial thin sections and well known soft operating. The designed method enabled us 1) to get serial sections of a single mouse embryo; 2) to create an orthogonal system indepen...

This work aims to assay the regulation of cytoplasmic potassium content in mouse zygote by the embryonic cell-specific 240 pS K +-channel. Intracellular potassium concentration were measured with Electron Probe Microanalysis for oocyte and embryos at different stages of development. The data obtained suggest that elemental changes in zygote cytopla...

It is shown that change of compartmentalization in zygote is synchronized with 240 pS K+ channel cycle. Analysis of potassium concentration in peripheral and central cell parts allowed estimating K+ diffusion coefficient under embryo conditions, the value appeared to be by 4-5 orders lower than that for electrolyte in aqueous solution. The explanat...

The details of the quantitative X-ray electron probe microanalysis performed with wave dispersive spectrometer are described. Hydration of biological tissues, light element composition, low concentration of analyzed elements and their nonuniform distribution are the specific features of bioorganic film and tissue section. This work is aimed to disc...

Comparative analysis of potassium concentrations in the cytoplasm of intact and enucleated one-cell mouse embryos of showed that microsurgical manipulations during collection of pronuclei disordered potassium homeostasis in the embryonic cell.

We propose a method of evaluation of anticlimacteric efficiency of a drug by its effect on the estrous cycle. The study was carried out on 9-month-old mice with retained, but notably reduced reproductive function. Analysis of the cell components of the estrous cycle was carried out on histological preparations of vaginal smears.

The need for effective methods of cryopreservation of early mammalian embryos necessitates the study of the mechanisms of blastomere adaptation to the equilibration procedure and subsequent washing from the cryoprotector. The osmotic effects during these procedures can cause electrolyte imbalance in embryonic cells. Intracellular potassium concentr...

Direct effects of cardiotropic preparations on the hearts isolated from Wistar rats were examined. Deenergization of cardiomyocytes was modeled under conditions of hypoxic perfusion. Recovery of cardiac function during reperfusion was assessed by changes in the heart rate and contraction amplitude.

Using the electron probe microanalysis, potassium and sodium concentrations were measured in Wistar rat cardiac muscle cells. Hypoxic conditions were modeled according to the protocol of global ischemia in the absence of perfusion or via anoxic perfusion without glucose. It was shown that depending on the scheme of realization of hypoxia the change...

In order to successfully continue works in area of cloning, it is necessary to study mechanisms of interactions between embryo cells at early stages of development. However, it is difficult to identify the cell which participate in construction of embryo proper. In connection with this, three-dimensional reconstruction of micro-objects is applied f...