Folding of model polypeptide sequences consisting of 50 and 150 amino-acid residues with the alanine and glycine repeat was explored using Langevin dynamics techniques at different values of the viscosity of a virtual medium. The starting conformations corresponded to a totally extended chain structure. The change in the dissipative properties of the medium was simulated under varying parameters of

Using the voltage-clamp technique, it has been shown for the first time that the neuroleptic drugs chlorpromazine and trifluoperazine, which act as sigma-1 receptor antagonists, attenuate Na+ transport in the frog skin epithelium. The results suggest that sigma-1 receptors may be involved in the regulation of transepithelial Na+ transport in frog skin.

Many studies have been devoted to the passage of bees during the winter period, which indicate that this state of the bee family is yet to be understood. However, the most critical period for bees is late winter and spring. At this time, there are large temperature fluctuations in the air, and from time to time, bees are forced to switch from a passive state to an active state and vice versa. This

Changes in the electrical properties of blood corpuscles that are experiencing mechanical stress modeled in vitro have been studied. An increase in the concentration of ATP molecules in the intercellular space in response to the mechanical effect of moving plasma layers both in the blood of healthy people and patients with acute lymphoblastic leukemia is demonstrated. The surface potential of red blood

Complex causal relationships occur between population dynamics and a change in a population genetic structure. In our study, a simple model was used to show that the evolutionary process of density-independent natural selection depending on the fitnesses determined by a single diallelic locus can lead to a change in population growth parameters, thus changing the dynamic modes in a population. Possible

The results of biomonitoring of the Olkhovaya River (Donetsk oblast) are presented. The impact of mine sludge waste on the state of surface water was shown. The assessment of physical and chemical parameters made it possible to characterize the water in the Olkhovaya River as dirty and polluted with a large number of suspended coal particles, whose content significantly exceeded the maximum permissible

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 phosphatidylcholine (lecithin) onto the surface of

We have investigated the effect of colchicine, a disrupting agent of the tubulin cytoskeleton, on chlorophyll fluorescence parameters, the Hill reaction, noncyclic photophosphorylation, and the lipid peroxidation reaction in Solanum tuberosum grown in soil in a greenhouse environment. The destruction of microtubules caused an increase in the content of lipid fatty acid hydroperoxides, the primary product

Several models have been considered: those that describe mutation fixation in asexually or sexually reproducing species during speciation and are based on stochastic processes and a percolation selection lattice for mutation selection through generations and a trigger model of mutation fixation in a population cluster, which are based on both stochastic and deterministic processes. Lower (reversible

Abstract This paper mainly deals with the prey−predator dynamics where both the prey and predator exhibit herd behavior. Positivity, boundedness, some extinction criteria, stability of possible equilibrium points are discussed with some global behavior, in an innovative approach. Numerical simulations are represented to clarify the analytical discussions. The biological implications of analytical and

Energy transduction reactions in the photosynthetic membrane are a primary step in storing solar energy to be used later in biosynthetic and other processes in living systems. This review summarizes the recent data on modeling photosynthetic electron transport that were obtained at the Department of Biology, Moscow State University. Mathematical models of various types were used to simulate the processes

The pre- and postsynaptic effects of ATP on thermal sensibility in the diaphragm of the rat have been studied. It has been found that reduction in the bath temperatute from 37 to 22°С provokes a decrease in contractile force of diaphragm caused both by electrical stimulation and carbachol. At 37°C adding ATP to the incubation medium increases contractive activity of the diaphragm caused both by electrical

The physical regularities that lead to isotope fractionation and to the accumulation of certain isotope forms in the intercellular and intracellular space at various levels of biological objects were studied. A new hypothesis of fractionation of stable isotopes in biological objects through the neutron effect was discussed. The following feature is noted: it is very likely that the development of isotope

The effects of ozone on oxygen transport in the blood of experimental animals have been studied in vitro. Incubation of the blood with ozonated water at О3 concentrations of 2, 6, and 10 mg/L for 30 and 60 min caused changes in the oxygen-transport function of the blood, thus leading to increased oxygen tension and oxygenation, as well as reduced affinity of hemoglobin for oxygen. As a result, the

Analysis of the spatial arrangement of the drosophila retina has shown that the structure of cell layers can be represented by three-dimensional stack-like cell lattices. These lattices simulate the topology of cell layers and are a new object of histology. The proposed approach to studying these lattices is to construct a series of models of the spatial arrangement of tissues, to compare model sections

This paper is focused on the dynamics of the formation of conditioned responses in rats that experienced 14-day moderate magnetic shielding and were placed into a shelter setup when conducting the Barnes maze task. It was found that the acquisition rate of the conditioned active avoidance response was faster in rats under magnetic shielding conditions than that in the control animals. A direct accelerating

The influence of the nature of the ligands of nitric oxide-generating compounds, such as binuclear dinitrosyl iron complexes containing glutathione or mercaptosuccinate, on their tumor growth-inhibiting and cytotoxic effects has been studied in vivo and in vitro. The antitumor effect of the complex with glutathione exceeds that exerted by the complex with mercaptosuccinate. These complexes inhibit

A comparative analysis of the survival rate of the human gut microbiota after low-temperature preservation under the protection of penetrating (dimethylsulfoxide and glycerol), nonpenetrating (gelatin) and gas (helium) protectors was performed. Increased resistance of intestinal bacteria to the effect of low temperatures was revealed. A significant portion of the bacteria (50.0 ± 3.0%) remained viable

The pathogenesis of diseases of the gastrointestinal tract in horses is accompanied by inflammation and oxidative stress and may be caused by a lack of nitric oxide, which controls various signaling pathways in the body. The level of nitrites, which are metabolites of nitric oxide in horses with various intestinal diseases, has been evaluated in blood serum at 3.60 ± 3.02 μM and 8.3 ± 6.0 μM in horses

This review considers the molecular mechanisms involved in the redox regulation of the Na,K-ATPase. The enzyme creates a transmembrane gradient of sodium and potassium ions, which is necessary for the vital activity of all animal cells, and acts as a receptor of cardiotonic steroids (CTSs), which regulate cell proliferation and apoptosis. The function of the Na,K-ATPase depends on the cell’s redox

Electron paramagnetic resonance spectroscopy has been applied for the first time to study the bio-distribution of magnetoliposomes formed with magnetite nanoparticles (Fe3O4) in tumors and organs of Lewis carcinoma-bearing mice in the absence and presence of an external magnetic field. The animals of the experimental group were subjected to an external magnetic field (0.6 T) in the tumor area after

Abstract Penetration of a microelectrode into the cell soma is one of the most vulnerable stages of the method intracellular recording. Traumatic neuronal activity after piercing the membrane with a microelectrode can be an indicator of neuronal damage. In this paper we report the results from tests of our pulse electromagnetic micromanipulator. This device is designed to reduce the neuronal damage

Several models of long short-term memory (LSTM) neural networks were constructed. Each model was trained on the complete mouse genome to predict the exon–intron structure of a gene. The performance of the neural networks was compared using a test sample and experimental sequencing data obtained using rat brain cell cultures after treatment with spicing inhibitors.

Abstract Gold nanoparticles are promising radiosensitizers for proton radiotherapy. However, the physical mechanisms of gold nanoparticles radiosensitization remain unclear. In the present study, the Geant4 toolkit was used to estimate by the Monte-Carlo simulation the changes (1) in the contribution of primary and secondary particles to the absorbed dose, (2) in the dose-averaged linear energy transfer

The DBSCAN clustering algorithm, an in-house method of unsupervised machine learning, was used to explore specific histotopographical features of the megakaryocytic lineage in the bone marrow biopsies of patients with JAK2- or CALR-mutated essential thrombocythemia and prefibrotic primary myelofibrosis. Ninety-five bone marrow biopsies of patients with essential thrombocythemia and primary myelofibrosis

Studies on the effects of an electromagnetic field on the activity of recombinant luciferase in the luciferase–luciferin–ATP-Mg2+ system were conducted. The enzymatic activity was evaluated by the measurements of biochemiluminescence intensity with a standard chemiluminometer. Frequencies that effectively caused irreversible changes in the enzyme activity were identified. The intensity of chemiluminescence

High organoprotective properties of a carbon monoxide (CO)–oxygen (O2) gas mixture were confirmed after prolonged (24-h) preservation of the papillary muscle and an isolated rat heart at 4°C. Hypothermic preservation in the high-pressure gas mixture (6 atm) provided efficient restoration of the contractile activity of the isolated rat heart after 24-h storage at 4°C. The isolated retrograde-perfused

Ligand binding to DNA duplexes in a DNA biosensor was studied in conditions where the number of ligand molecules in the solution fluctuates under the influence of a fluctuating medium (external noise). A multiplicative stochastic differential equation was obtained for the case of low occupancy to describe the time-dependent change in the number of ligands absorbed on DNA duplexes. The average value

We have studied the contrast sensitivity of the visual system in various ranges of the spatial frequencies in “dry” immersion conditions that simulate the physiological effects of microgravity. The contrast sensitivity in the range of low and high spatial frequencies is indicative of the functional state of the magnocellular and parvocellular neuronal pathways that form the dorsal and ventral information

Abstract This study deals with participation of isoquinoline derivatives of coumarin in the peroxidase reaction catalyzed by the cytochrome c–cardiolipin complex. We have studied coumarin derivatives called coumarin-314 (C-314), coumarin-334 (C-334) and coumarin-525 (C-525). These substances are considered as specific physical activators of chemiluminescence, which accompanies the lipid peroxidation

Nanoparticles with a high atomic number are of interest as radiosensitizers for radiation therapy of cancer. A variety of nanoparticles and radiation sources makes the challenge of selecting their optimal combinations to achieve maximum irradiation efficacy relevant. In this work, we calculated the values of the dose enhancement factors of elemental compositions of metal oxide nanoparticles (Al2O3

The cellular mechanisms of pacemaker-cell activity and the contribution of various ion channels of the embryonic heart are not yet fully understood. This paper presents the results of an experiment to study the effects of specific ion-channel inhibitors on the generation of action potentials in pacemaker cells of the right atrium in chicken embryos. It has been found that the exclusion of calcium ions

The appropriateness of verification of the possible antiviral effect of dinitrosyl iron complexes with thiol-containing ligands as donors of nitrosonium cations (NO+) is argued. There is reason to hope that treatment of the human respiratory tract and lungs with sprayed solutions of dinitrosyl iron complexes with glutathione or N-acetylcysteine (NAC) ​​as NO+ donors during COVID-19 infection can initiate

This review is focused on literature data and our own research of the nontrivial quinoid pathway for the oxidation of adrenaline. All catecholamines can be oxidized similarly with formation of corresponding aminochromes. This process is simulated in vitro in an alkaline medium and is known as the adrenaline autoxidation chain reaction, whose products are adrenochrome and radical compounds, superoxide

Abstract The involvement of natural radicals in single-electron processes of cell activity is considered. It was shown that coenzymes that have intermediate free radical quinoid and semichinoid forms can interact with carotenoids to form complexes with a charge transfer with an absorption band of 1030 nm. Moreover, the complex can perform an active light-harvesting function during photosynthesis up

Much attention is given to research and development of efficient systems for the delivery of essential omega-3-polyunsaturated fatty acids and other nutraceuticals to the human body with food. Nanocomplexes, which are based on soybean phosphatidylcholine liposomes with nutraceuticals included, are among the efficient delivery systems. The prolonged use of these nanocomplexes may affect the antioxidant

We investigated the effects of the H2S and CO gasomediators on Ca2+-dependent potassium channels and an anion exchanger, which participate in the induction of the hyperpolarization response of the erythrocyte membrane and play an important role in regulation of the volume and deformability of erythrocytes. We showed that in the presence of H2S and CO donors, the amplitude of the redox-stimulated membrane

Abstract A hypothesis is proposed that the cytokine storm syndrome, which complicates COVID-19 in some patients, is a consequence of antibody-dependent enhancement of virus infection, which is in turn happens due to a change in dominant antigenic determinants of SARS-CoV-2 S-protein. The antibody-dependent enhancement of virus infection is a phenomenon in which virus-specific antibodies that are not

The effects of radiation from the young Sun and galactic cosmic rays on the physical conditions on the early Earth are significantly underestimated in studies of the problems related to the origin and evolution of the biosphere. This review considers the dynamics of solar and galactic processes over the 4.56 billion years of the existence of the Solar System. These factors substantially affected the

This study demonstrates the susceptibility of the Escherichia coli and Bacillus subtilis planktonic bacteria to inactivation by shock acoustic waves that arise from the rapid formation and collapse of vapor bubbles in a medium locally heated to its boiling point. Local heating of the medium occurred due to heat release through the relaxation of highly excited electronic states of exogenous molecules

We studied the effects of whole body gamma-radiation (4 Gy, dose rate 0.6 Gy/min) and proton-beam head irradiation (with an energy of 150 meV, 4 Gy and a dose rate of 0.8 Gy/min) on the intensity and timing of audiogenic seizures in rats of the Krushinsky–Molodkina selected strain. In experiments using gamma rays the rat behavior was tested in the open field, elevated plus maze, and Morris water maze

The crown of the Siberian fir ( Abies sibirica ) is characterized by a specific organization, namely, a narrow-pyramidal form, apical dominance, tiering by types of sexualization, and whorled branching. The gravitational vector is clearly manifested at all levels of the organization of the crown, that is, in the architecture (diageotropism of branches), morphostructure (dorsoventrality of tissues and

Growth-stimulating effects of water-soluble nanoparticles of N-substituted monoamino-acid derivatives of fullerene C60 (L- and D-alanine, L- and D-valine, L- and D-aspartic acid, β-alanine, and γ-aminobutyric and ε-aminocaproic acids in potassium salt form) were investigated. It was found that the nanoparticle size and relative antiradical activity of fullerene derivatives were factors that influence

This paper reports that pre-incubation of a neutrophil suspension in the presence of a near-null magnetic field produced using a system of magnetic shields (a residual constant magnetic field not greater than 20 nT) results in a considerable decrease in the intensity of neutrophil lucigenin-dependent chemiluminescence. The addition of the NADPH oxidase inhibitor diphenyliodonium to the incubation medium

It has been shown that the main components of levorin A, that is, A0, A1, A2, or A3, that contain an aromatic group increase the permeability of membranes in the series A3 > A2 > A1 > A0 when they are on the same side of the membrane. All levorin components have cationic selectivity. The most studied levorin, А2, promotes the almost ideal permeability of membranes to potassium ions. The membrane potential

The content of damaged 8-hydroxy-2-deoxyguanosine nitrogenous bases in the blood DNA of healthy donors and patients with epidermolysis bullosa after exposure to an alternating magnetic field of 550 ± 30 A/m in the frequency range from 3 to 60 Hz in vitro was determined using an enzyme immunoassay. The degree of oxidative DNA damage in epidermolysis bullosa was almost twice as high as in healthy donors

This review is dedicated to the memory of Dr. Sergei L’vovich Grokhovsky, who was a distinguished scientists and experimenter; it briefly describes one aspect of his multifaceted research activity. Gro-khovsky was the first to describe the specificity of ultrasound-induced cleavage of internucleotide bonds in double-stranded B-DNA. The discovery of this new physicochemical phenomenon made it possible

Astaxanthin and its esters, which are classified as secondary carotenoids, are synthesized under stress conditions in Haematococcus pluvialis cells that undergo transformation from vegetative cells to hematocysts. Stress factors can affect not only the rate and the direction of synthesis, but also the conformational changes in the pigment molecule, causing conversion of trans-isomers to cis-isomers

It was shown that 40-min exposure of peritoneal neutrophils to hypomagnetic conditions (with a residual field of 0.01 μT) caused a significant (25%) decrease in the intensity of intracellular dichlorofluorescein fluorescence. This effect of the weak magnetic field persisted if the constant magnetic field was increased to 1 μT. Upon further increase of the field to 2.5 μT, the effect of the field disappeared

An original method for visual-differential analysis of conformational features in (bio)macromolecular structures is applied to theoretical study of the differences between the structural organizations of the D and L chiral forms of diphenylalanine nanotubes. Common features in the spatial organization of the inner surfaces of nanotube channels are described: The mirror positions of hydrophilic atoms

Cryopreservation of fish and amphibian eggs is still an unsolved problem. The formation of ice crystals inside and outside cells acts as a main detrimental factor during a deep freezing of fish eggs, as well as crystal growth (recrystallization and repeated crystallization). Designing efficient cryoprotective media is necessary in order to avoid egg injury from freezing. Additional components that

AbstractThe effect of temperature on the kinetics of erythrocyte hemolysis induced by tert-butyl hydroperoxide and dinitrosyl iron complex with thiosulfate ligands was studied. The inverse of the time needed to achieve 50% hemolysis was used as an estimate of the rate of hemolysis. This has afforded us an opportunity to present the obtained experimental data in the form of linear graphs of Arrhenius

The specific characteristics of the distribution of secondary structures and coiled-coil superhelix structures were investigated for the first time, while taking the sign of chirality into account, in polypeptide chains of proteins belonging to eight functional classes: viral proteins, chaperones, oxidoreductases, hydrolases, structural proteins, proteins involved in exocytosis and endocytosis, and

Bees, wasps, and ants have no specialized receptors for the perception of an electric field. An appropriate response to naturally occurring electric fields in bees and ants is associated with atmospheric exposure, amplified by the approach of the front of a thunderstorm. The primary transducers of mechanoreceptors that respond to displacement are related to the perception of low-frequency electric

Abstract—The round-the-day effect of solar radiation on photoreceptors of the retina of the eye and its role in the control of the circadian rhythm of the human body within an arbitrary 11-year cycle of solar activity are considered. Processed data describing the variation of the spectral and energy characteristics of solar radiation that reach the Earth’s surface over a solar activity cycle are given

The effects of different magnesium and zinc isotopes on the enzyme activity of myosin subfragment-1 have been explored. The rate of the enzymatic ATP hydrolysis in reaction media enriched with the magnetic isotope, 25Mg, is twice as high as it is in reaction media enriched with the nonmagnetic isotopes, 24Mg or 26Mg. A similar effect of nuclear spin catalysis has been detected in the experiments with

In this paper, we discuss experimental data obtained during study of the effect of a low-frequency alternating magnetic field on the conformational transitions of human serum albumin in the presence of silver nanoparticles using fluorescence spectroscopy at different pH values. A sharp increase in the albumin fluorescence intensity was detected in the presence of silver nanoparticles; this effect changed

Sea urchins and their relatives are grouped together taxonomically in the class Echinoidea (phylum Echinodermata). Echinoids exhibit remarkable variation in their pentaradially symmetric body shape phenotypes, from spheroid tests (skeletons) in sea urchins to discoid tests in sand dollars. Researchers have speculated on the morphological evolutionary transitions among these phenotypes without reaching

The effect of terahertz radiation on the functional activity of bovine serum albumin was studied by electron paramagnetic resonance spectroscopy using spin trapping and spin probing techniques. The use of a pH sensitive imidazoline spin trap allowed us to record the change in the binding strength of albumin with nitric oxide. The change in the intensity and width of bands in the EPR spectrum of the

This review considers the basic models of mutation processes that occur during selection and drift. A basically new model was developed to describe the mutation flow through a percolation lattice of selection at the population level. Natural selection of optimal variants in the evolutionary flow of mutations was considered as a percolation filter, which acts as a physical tool that forms the mechanism