bluuebunny/crossref_metadata_2025 huggingface dataset:
Revisiting the role of ectonucleotidases in synaptic transmission. Thermal sensitivities of ATP-producing metabolic pathways
Authors: Khairullin A. E , Efimova D. V , Ivanova D. V , Grishin S. N , Ziganshin A. U
Published: April 2024

The release of ATP as an intermediate at the neuromuscular junction, and acetylcholine, the chief neurotransmitter, may take place by mechanisms responsible for quantal and non-quantal secretion from the motor neurons of the central and peripheral nervous system. The dephosphorylation pathway of ATP that is completed by the hydrolysis of AMP to adenosine in the synaptic cleft is a cascade of reactions catalyzed by ectonucleotidases. These enzymes are of enormous interest, the research in this field is necessary to clarify their role in a complex signaling cascade, since it is known that they have dual functions: ectonucleotidases limit the action of ATP as a neurotransmitter and participate in the formation of other neuromodulators (ADP, AMP and adenosine). In addition, ATP and its metabolites can cause completely different physiological effects. The activity of ectonucleatidases in different types of skeletal muscles was determined, it varies within 5-7 IU. A decrease in temperature to 22°C leads to a multiple decrease in the enzymatic regeneration of ATP in skeletal muscle tissues. It is assumed that enzymatic limitation of ATP and the production of its metabolites ensures stabilization of effective cholinergic neuromuscular transmission in norm and pathology.
Use of peroxiredoxin 6 to prevent liver dysfunction in acute kidney injury
Authors: Gordeeva A. E , Kurganova E. A , Novoselov V. I
Published: April 2024

Acute kidney injury causes deterioration of liver function, that is a confounding factor affecting treatment outcomes. In this work, renal ischemia reperfusion injury was used as a model. Taking into account that hyperproduction of reactive oxygen species is the major risk factor for kidney damage, the exogenous antioxidant enzyme peroxiredoxin 6, able to neutralize reactive oxygen species, has been used to prevent liver damage when kidneys are damaged. Kidney injury was initiated by a 45-minute ischemia simultaneously with a left-sided donor nephrectomy without manipulations of the liver. Peroxiredoxin 6 was administered intravenously 15 minutes before ischemia. The functional state of the liver was assessed after 2, 5 and 24 hours of reperfusion using histological and biochemical analysis. The signs of liver damage were detected in the best possible way after 5 hours of kidney reperfusion. It was found that peroxiredoxin 6 helps reduce the severity of the vascular reaction and leukocyte infiltration in the liver; lower the level of dystrophy and apoptosis of hepatocytes; keep the concentration of TBA-reactive products even and stabilize the level of cytokines, IL-6 and IL-10, in the liver tissue, as well as normalize the activity of intracellular transferases in the blood at the onset of reperfusion. The protective effect of peroxiredoxin 6 is associated primarily with its antioxidant properties, due to which hyperproduction of reactive oxygen species can be neutralized in the early phase of kidney reperfusion, but the signal-regulatory function of the protein can also contribute to a protective role peroxiredoxin 6.
A raman spectroscopic investigation of conformation of flavin adenine dinucleotide, a coenzyme of d-amino acid oxidase
Authors: Bochkova J. V , Liu W. , Brazhe N. A , Zhgun A. A , Maksimov G. V
Published: April 2024

Based on silver nanoparticles application, surface-enhanced Raman scattering spectra of D-amino acid oxidase from pig kidney were recorded and analyzed. Spectral parameters characteristic of conformational changes in cofactor flavin adenine dinucleotide during activation of the enzyme by D-amino acids were revealed. It was found that enzyme substrate specificity determines the amount of time from the start of of the conformational changes of flavin adenine dinucleotide until they no longer occur: in the presence of D-alanine, registration of the said conformational changes takes up just a few seconds, while it takes 10 min in the presence of D-serine .
The specificity of interactions between endoinulinase from Aspergillus ficuum and mono-, diand polysaccharides
Authors: Makin S. M , Dubovitskaya A. N , Bogomolov D. Yu , Kondratyev M. S , Holyavka M. G , Artyukhov V. G
Published: April 2024

The aim of this study was to analyze the peculiarities of spatial organization of an endoinulinase molecule from Aspergillus ficuum after its binding to mono-, di-, and polysaccharides. This study examined changes in volume and number of internal cavities upon binding of inulinase to mono- (glucose, fructose), di- (sucrose, mannose), and polysaccharides (inulin). Transformations in the quantity and length of tunnels and pores were described, and the reorganization of the composition and localization of charged and hydrophobic amino acid residues clusters on the surface of the enzyme molecule was analyzed. It was shown that the models of inulinase in the complex with sucrose (an alternative substrate) and mannose (an activator) exhibit the same types of internal structures. The similar pattern was found in the formation of complexes with fructose (a reaction product) and glucose (an inhibitor). In addition, it was established that both charged and hydrophobic clusters do not undergo significant changes in chemical composition after the binding of inulinase to mono-, di-, and polysaccharides, i.e., the interaction between inulinase and carbohydrates mentioned above primarily affects the internal structures of the enzyme. The specificity of the binding of inulinases to various ligands should be taken into account while developing modern industrial biocatalysts based on inulinase.
Updating nucleosome positions within individual genes using molecular modeling methods and mnase sequencing data
Authors: Vasilev V. A , Ryabov D. M , Shaytan A. K , Armeev G. A
Published: April 2024

Organization of chromatin plays an important role in regulating the genetic machinery of the cell. The basic unit of chromatin packaging is a nucleosome, which harbors DNA of about 145 base pairs in length. The packaging of genetic material and its accessibility to transcription enzymes and other regulatory chromatin proteins depends on the positions of nucleosomes. MNase sequencing is used to examine nucleosome positions in a genome. MNase sequencing data are sufficient for detecting the presence of nucleosomes on the sequence, but a determination of the precise locations of nucleosomes can be problematic. Accurate determination of nucleosome positions requires additional data filtering and processing. In this study, using MNase sequencing data, a combined method based on geometric analysis of nucleosome chain molecular models is proposed for selecting possible nucleosome positions. The developed algorithm efficiently eliminates inaccessible nucleosome chain combinations and conformationally prohibited nucleosome positions.
A study on the radiosensitivity and induction of adaptive response in peripheral blood lymphocytes of patients with secondary immunodeficiency syndrome
Authors: Rozanova O. M , Smirnova E. N , Belyakova T. A , Strelnikova N. S
Published: April 2024

This study examined radiosensitivity at low and high dose exposure to X-rays in human lymphocytes and the ability of low and high dose radiation to induce radioadaptive response when the peripheral blood cells from patients with secondary immune deficiency syndrome and healthy donors of different ages were irradiated in vitro. The frequency of micronuclei in cytochalasin-blocked binuclear lymphocytes in culture served as an indication of cytogenetic damage. It was found that the spontaneous level of cytogenetic damage in blood lymphocytes of patients with secondary immune deficiency syndrome was 2.5 times greater than that of healthy young and older volunteers and there was also a substantial interindividual variability in outcome parameters as compared to the data of control groups. There were no differences in mean values for radiosensitivity at low and high dose exposure of X-rays between the groups. In all groups, no correlation was shown between the spontaneous level of micronuclei in lymphocytes and the radiosensitivity of individuals. The adaptive response was induced with the same frequency and to the same extent in lymphocytes in patients with secondary immune deficiency syndrome and in healthy donors of different ages.
Effect of taxifolin, a conjugate of taxifolin with glyoxylic acid, and naringenin on the functional activity of neutrophils
Authors: Shubina V. S , Kobyakova M. I , Shatalin Yu. V
Published: April 2024

The aim of the present work was to study the effects of taxifolin, a conjugate of taxifolin with glyoxylic acid, and naringenin on phagocytosis of latex beads by neutrophils and adhesive properties of these cells. It was shown that taxifolin had no effect on the phagocytic activity and adhesive properties of neutrophils. A conjugate of taxifolin with glyoxylic acid strongly inhibited the phagocytic activity of neutrophils. At the same time, the conjugate significantly enhanced adhesion of these cells. Naringenin decreased phagocytic activity of neutrophils, though to a lesser extent than the conjugate did. Naringenin also inhibited adhesion of neutrophils. Thus, the data collected during our study indicate that polyphenols may influence the functional activity of neutrophils that can play an important role in the modulation of inflammation, especially when prolonged activation of neutrophils leads to tissue damage.
Role of nitric oxide and calcium ions in the effects of hydrogen sulfide on contractile activity of rat jejunum
Authors: Sorokina D. M , Shaidullov I. F , Gizzatullin A. R , Sitdikov F. G , Sitdikova G. F
Published: April 2024

This study was performed to explore the role of nitric oxide, intracellular and extracellular calcium in the effects of hydrogen sulfide on spontaneous and carbachol-induced contractions of a rat jejunum preparation during a isometric contraction. Application of H2S donor, sodium hydrosulfide, led to a decrease in tonic tension, the amplitude and frequency of spontaneous contractions, as well as in the amplitude induced by carbachol, a nonspecific acetylcholine receptor agonist. Inhibiting the production of endogenous NO synthesis by with L-NAME, the effect of H2S donor remained unchanged, while in the presence of SNAP, a NO donor, the effects of NaHS on the amplitude of spontaneous and carbachol-induced contractions were less pronounced. Dantrolene, a ryanodine receptor inhibitor was used to stop a decrease in tonic tension in the presence of NaHS. The calcium-free solution reduced the inhibitory effect of NaHS on carbachol-induced contractions. This suggests that the inhibitory effect of H2S is associated with the dynamics of the intracellular concentration of calcium ions, and the interaction between NO and H2S occurs at the level of common targets of two gases.
Minimal model for the dependence of stresses in the wall of a cerebral vessel on the parameters of a smooth muscle cell
Authors: Shadrina N. Kh
Published: April 2024

A minimal mathematical model of the wall of a small arterial vessel is described. This model is created based on the published results of experiments performed on rat cerebral vessels. It is assumed that the active stress has only a circumferential component and depends on the circumferential stretch, calcium concentration in the cytoplasm, and the membrane potential of smooth muscle cells. The presented model for a small artery can qualitatively reproduce the results of more sophisticated models for other vessels under normal physiological conditions. Unlike a similar model, that accounts for only one cellular parameter, the addition of membrane potential as one of the main parameters was crucial to reveal a qualitative change in the dependency of circumferential stress on stretch and the radial coordinate with an alteration in vascular tone. At fixed values of membrane potential and calcium concentration in the phase of a development of vascular tone, stress decreases as it approaches the outer wall of the vessel and increases as stretch increases, and after it is formed, the direction of changes in the circumferential stress reverses.
Trend analysis of the current epidemic situation and analysis of factors underlying local uneven spread of covid cases
Authors: Perevaryukha A. Yu
Published: April 2024

This research has been carried out by analyzing the specific processes of the local epidemic dynamics of COVID by comparing the qualitative differences in fluctuations in 2020 and 2023. Methods of nonlinear dynamics of the development of epidemic processes in a rapidly changing situation were used to identify and qualify trends and unique situations that sometimes changed extremely fast. A distinctive feature of the modern pandemic is a rather sharp change in local trends: the effect of the fading of the primary outbreak of the disease and the sudden sharp onset of a new epidemic wave after a long trend of decreasing daily infections. Minimization of the exposure to viral infections did not prevent spreading the virus but created the illusion of success. The existing experience in generating forecasts of epidemic outbreaks based on models of past epidemic processes could not help when faced with a new evolving virus. The previously obtained understanding of the development and completion of epidemic processes of influenza virus strains more likely hindered the prediction of the scenario for the completion of the spread of a new infection, which is also associated with the eventual nature of the process and a variety of dynamic situations. A victory over COVID in the phase of the minimum after the wave, which was announced by many countries, turned out to be premature. New Zealand and Japan, which opted for a strict lockdown strategy in 2020, had a surge of COVID cases in early 2023 because new strains came into circulation. Outbreaks of respiratory diseases known as the Spanish flu and swine flu pandemics, data from which were used by many countries to make predictions, had run their course naturally in two or three waves of illness. At the beginning of 2023, against the backdrop of a global positive trend, some countries have reported a record rise in both mortality and daily morbidity due to the emergence of locally circulating “alarm” strains. A current stage on isolation of stable regional strains substantiates the classification of a series of differentiated properties of the dynamics of regional epidemic situations. Among the observed epidemic effects, extreme phenomena in the form of instantaneous bifurcation destruction of established regimes such as a sharp transition from long-term damped oscillations to a new exponential outbreak in some infections are separately highlighted. The selected options for the development of epidemic transient oscillatory processes are separately introduced in equation forms with delay for local epidemic trends. Equations are proposed to describe three variants of development of the observed stages of local epidemics. The task of constructing a generalized predictive model of a pandemic to describe interrelated regional processes at this stage seems insoluble.
On illusion of flying dreams. the mechanism of their occurrence
Authors: Ivanitskii G. R
Published: April 2024

It is shown that there is no need to resort to exoteric hypotheses to explain flying in a dream. From a biophysical point of view, the phenomenon of "flying in a dream" is based on the already studied adaptive mechanisms and daily rhythms of the human body. During sleep, the brain's arousal thresholds are lowered, making it easier to arouse the brain with weak signals. This study considers one of the mechanisms of such excitation with a change in body position, which is perceived by the brain in the rapid eye movement sleep phase as a decrease in body weight, which, under certain conditions, can cause the illusion of flying in the brain.
Interaction of magnesium ions with semiquinone radicals of tiron used as an indicator of reactive oxygen species
Authors: Ustynuyk L. Yu , Medvedeva V. A , Liubimovskii S. O , Ruuge E. K , Tikhonov A. N
Published: April 2024

Electron paramagnetic resonance spectroscopy (EPR) and quantum chemical calculations based on density functional theory were used to demonstrate that the earlier observed changes in the EPR spectra of Tiron semiquinone radical dissolved in sea water solution occur due to interaction of Mg2+ ions with Tiron radical. This interaction is caused by electrostatic attraction between Mg2+ ions and Tiron radicals, which bears great charges of opposite sign (+2 and -3), on the one hand, and due to the ability of Mg2+ ion to bind to bidentate oxygen-containing ligands efficiently, on the other hand. The formation of tight contact ion pairs leads to electron and spin density redistribution in the Tiron radical, as can been seen by the observed changes in the EPR spectra of the radical.
Spatial structure of soymorphin-6 molecule
Authors: Agaeva L. N , Abdinova A. A , Akhmedova S. R , Akhmedov N. F , Akhmedov N. A
Published: April 2024

By the method of the theoretic conformational analysis the conformational capabilities of the soymorphin-6 (Tyr1-Pro2-Phe3-Val4-Val5-Asn6-NH2) molecule were studied. The potential energy of this molecule is given as the sum of nonvalent, electrostatic and torsional interactions and the energy of hydrogen bonds. Low-energy conformations of the soymorphin-6 molecule, the values of the dihedral angles of the main and side chains of amino acid residues that make up the molecules are found, the energy of intra- and inter-residual interactions is estimated. It is shown that the spatial structure of the soymorphin-6 molecule can be represented by eight conformations. The results obtained can be used to study the structure and structural-functional organization of the soymorphin molecules.
Exploring the fluorescence action spectrum of photosynthesis
Authors: Zienko S. I , Zhbanova V. L
Published: April 2024

The mathematical study of the fluorescence action spectrum of photosynthesis was performed. The calculation of typical spectra for photosynthesis was done for the red and blue frequencies. The transition of the action spectrum of photosynthesis from wavelengths to the frequency scale was completed. A numerical method based on the use of the inverse Fourier transform approach was used to obtain a relaxation curve for the impulse (time) characteristic of fluorescence. It turned out that the radius vector of the module of impulse response in polar coordinates makes one half-turn or half of the period of light oscillations in time. It was established that the optical medium of a plant during the relaxation time has a negative space charge of electrons, inverse properties and properties of the coherent radiation. The condition of neutrality of the material environment is not met. It was found that the ratio of the variable chlorophyll fluorescence for red and blue light has almost the same value. An analysis of the dependence of the quality factor of the chlorophyll spectrum on frequency shows that the fluorescence energy loss in blue light significantly exceeds the energy loss in red light. The proposed method can be used for express analysis of the intensity of photosynthesis. It was also concluded that plants can emit ultra-wideband signals. The relaxation time of chlorophyll fluorescence is shorter than the relaxation time of electronic polarization in atoms (molecules). As a result, a population inversion is created in the optical medium of chlorophyll - there are more atoms in the upper energy level than in the lower level. Due to this, stimulated emission and amplification of light of the radiative recombination occur. In this case, the emission of fluorescence light becomes coherent. All these properties of plants are considered for the first time and have not been described either in domestic or in foreign articles.
Lipase and esterase activity in soils from ancient burial vessels
Authors: Kashirskaya N. N , Chernysheva E. V , Udaltsov S. N , Plekhanova L. N
Published: April 2024

The activity of lipolytic enzymes was assessed using the microplate method using heteromolecular exchange in soils from the bottom of burial vessels, followed by cluster analysis. Groups with a contrasting ratio of lipases C12 - C18 and esterases C4 - C8 were identified in a sample that included 57 burial pots aged two to three thousand years. The total lipolytic activity of soil samples from dishes with the presumptive initial presence of fat-containing food products was above 6% of the maximum value within the sample. Inhibition of esterases in the presence of high concentrations of fatty acids is reflected in the extremely low relative values of esterase activity of the soil microbial community against the background of maximum activity levels of C18 and C12 lipases in two groups of pots. In three groups, esterase activity was observed against the background of high relative activity of C16 lipases, average relative activity of C18 lipases and extremely low activity of true lipases. In the group of pots with high total lipolytic activity (with the exception of certain extreme values of this indicator), the proportion of true lipase activity was 1.7-1.8 times higher compared to the proportion of esterase activity. The grouping of burial vessels by the ratio of lipase and esterase activity reflects the characteristics of the funeral food, while the absolute values of enzyme activity among selected vessels with the highest total lipolytic activity are grouped according to the type of burial.
Dependence of the oxygen release intensity from red cells on the degree of their clustering in sludges
Authors: Ponomarev I. A , Guria G. Th
Published: April 2024

An efficiency of oxygen release from red cells strongly depends on the regimes of their motion through microvessels. Mathematical model of oxygen transfer taking into account the red cells ability to form intravascular sludges has been constructed and studied. An analytical expression for the dependence of the oxygen release intensity on the size of erythrocyte sludges were derived. The possible significance of the obtained results for the express diagnostics of the red cell’s ability for an oxygen transmission is discussed.
Comparative analysis of the degree of hydrolysis of biopolymers in hyaline cartilage homogenates in the presence of proteolytic enzymes
Authors: Nikolaeva T. I , Barsuk D. A , Molchanov M. V , Prokhorov D. A , Emelyanenko V. I. , Shekhovtsov P. V
Published: April 2024

Investigating the degree of hydrolysis in the presence of different proteolytic enzymes is one of the tasks regarding further development of nutraceuticals obtained from connective tissues for biomedicine. Hydrolysis of biopolymers in cattle and swine tracheal hyaline cartilage homogenates was carried out in the presence of the following enzymes: pancreatin, chymopsin, papain and karipazim, a drug that contains papain, a proteolytic enzyme. This study shows that karipazim manufactured by MedFlorina LLC has better efficacy than karipazim manufactured by ZAO Vifiteh, and the greatest degree of hydrolysis for collagen occurrs at 60°C and karipazim concentration of 10%. More complete hydrolysis of proteoglycans was performed in the cattle hyaline cartilage homogenates, because the analysis of NMR spectra revealed the glucose, the final product of glycosaminoglycan hydrolysis.
Why gaseous nitric oxide inhalation does not influence on systemic arterial pressure in human and animal organisms?
Authors: Vanin A. F , Abramov A. A , Vagapov A. B , Timoshin A. A , Pekshev A. V , Lakomkin V. L , Ruuge E. K
Published: April 2024

The reason has been elucidated why gaseous nitric oxide inhalation does not produce hypotensive effect in human and animal organisms. The defect was completely removed when low molecular thiol solutions were added by intravenous pathway simultaneously with gaseous NO inhalation into the animals (rats). The proposition was made that gaseous NO molecules including through the lungs into the circulation of the blood are transformed as a result of one-electron mechanism oxidation into nitosonium cation (NO+) which are not capable of vasodilating and thereby hypotensive action on men and animals. NO+ cation binding with low molecular thiols results in the S-nitrosothiol (RS-NO) formation with following release of the nitrosyl component from the RS-NO in the form of neutral NO molecule characterized with hypotensive activity. The formation of another NO donor - dinitrosyl iron complexes with thiol-containing ligands did not occur in the animals. Hypotensive action observed in lungs could be determined by gaseous NO penetration trough external vascular wall followed by the activation of vasodilation and hypotensia inductor - guanylate cyclase enzyme immediately inside of vascular walls.
About the pathway of amyloid aggregation of titin
Authors: Bobyleva L. G , Uryupina T. A , Timchenko M. A , Udaltsov S. N , Vikhlyantsev I. M , Bobylev A. G
Published: April 2024

The process of amyloid aggregation is quite complex and poorly understood. In this work, having summarized previously obtained results on the aggregation of the multidomain smooth muscle protein titin, an attempt has been made to expand understanding of this process, and a new possible mechanism by which amyloid aggregation of titin may occur is delineated. Our main conclusion is that the ability of titin to form amorphous aggregates seems to be the only possible way of aggregation of this protein. Most likely, only separate parts of the molecules, but not the whole protein, are involved in the formation of the amyloid structure in amorphous aggregates of smooth muscle titin. This feature, given the large size of the protein molecule, distinguishes titin from other amyloid or amyloid-like proteins. The paper discusses the potential energy landscape underlying the formation of titin amyloid aggregates.
THE III ALL-RUSSIAN SCIENTIFIC CONFERENCE “PROBLEMS OF STUDYING AND PRESERVING THE PLANT WORLD OF EURASIA” DEDICATED TO THE MEMORY OF L. V. BARDUNOV (1932−2008) (IRKUTSK, LISTVYANKA, AUGUST 29−SEPTEMBER 3, 2022)
Authors: Krivenko D. A.
Published: April 2024

The III All-Russian Conference with the international participation “Problems of studying and preserving the plant world of Eurasia”, dedicated to the memory of Doctor of Biological Sciences, Professor, Honoured Scientist of the Russian Federation, Leonid Vladimirovich Bardunov (1932−2008) was held on August 29 − September 3, 2022. It was housed by the Irkutsk Scientific Center of the SB RAS (Irkutsk) and the Baikal Museum of the SB RAS (Listvyanka township). The Conference was attended by colleagues from 24 cities and other settlements of Russia and from 4 cities of 4 foreign countries, representing 48 scientific, scientific-research, educational, environment-oriented domestic organizations as well as 5 foreign ones. Six plenary lectures, 52 sectional ones and 4 poster sessions on various problems of modern botany were presented at the Conference.
PECULIARITIES OF SHOOTS OF AXES OF DIFFERENT ORDERS IN THE CROWN STRUCTURE OF ULMUS GLABRA (ULMACEAE) VIRGINAL TREES
Authors: Antonova I. S. , Televinova M. S. , Bart V. A.
Published: April 2024

The crown of model trees growing in natural habitats is characterized. An attempt was made to identify more conservative and stable traits of crown axes of different orders. The dependence of the composition of shoots of second-order axes on their position in the first-order axis of the maternal growth is shown. The relationship between the lifetime of the axes and the time of their growth (aging) is revealed. Skeletal axes of the second order show similar pattern of changing the number of shoots from year to year, but differ in the length of their constituent shoots. The axes of the third, fourth and fifth orders determine individual differences of trees, by adjusting them to specific habitats. It was revealed that the change in the dominance of the fourth order over the third one in the crown reflects the regulation of the crown development under specific conditions and the rate of ontogeny. Acrotonia in the form of a stronger development of lateral shoots in the second and third positions from above on the mother shoot is characteristic of all branching orders. With an increase of the branching order, the manifestation of acrotonia is smoothed out. In this regard, the shoots of high orders become more and more similar to each other, which is particularly associated with the manifestation of the aging effect.
GYNODIOECY IN NEPETA GONTSCHAROVII (LAMIACEAE)
Authors: Cheryomushkina V. A. , Godin V. N. , Astashenkov A. Yu.
Published: April 2024

Gynodioecy is described for the first time in Nepeta gontscharovii, an endemic herbaceous polycarpic plant from the Hissar Darvaz mountains (Tajikistan). N. gontscharovii forms the flowers of two types: perfect and pistillate, on different plants. Both types of flowers are median zygomorphic, tetracyclic, and heteromeric: pentameric in the perianth, tetrameric in the androecium, and dimeric in the gynoecium. The stamens in pistillate flowers have transformed into staminodes. We have observed that the values of the vast majority of the studied morphological traits in perfect flowers are larger than in the pistillate ones. Three criteria have been identified which allow to distinguish reliably the flowers of different sexual forms: the size of flowers and their parts, the ratio of the length of corolla tube and calyx, and the position of anthers. The perfect flowers are characterized by pronounced protandry. According to the determined pollen/ovules ratio (from 1286 to 1657), N. gontscharovii is to be considered as a facultative xenogamous species. Females were rare (6.6%) in the studied population. We discuss the presence and distribution of gynodioecy within the genus Nepeta and section Macronepeta and its adaptive significance for the N. gontscharovii population.
STRUCTURE OF THE EPIPHYTE MOSS COVER ON THE TREES IN MIDDLE TAIGA BLUEBERRY SPRUCE FOREST
Authors: Obabko R. P. , Kryshen A. M.
Published: April 2024

The paper presents the results of a study of the spatial structure of the distribution of epiphytes on the sample plot, and on the trunk of Picea abies (L.) H. Karst. The distribution of all trees and individual species on the sample plot, as well as most species of epiphytic mosses, does not differ from random. Only one species, namely Dicranum fuscescens Turner, which in this community grows only on the trunks of living trees, has an aggregated distribution, while all other epiphytic moss species are also found in the ground cover and their distribution in the communities is random. The epiphytic cover on the trunk of a spruce tree, in the conditions of the middle taiga blueberry spruce forest, has a structure consisting of stripes and spots of various types distributed along the humidity gradient.
RECORD OF BOTRYCHIUM MATRICARIIFOLIUM (OPHIOGLOSSACEAE) IN ORYOL REGION (EUROPEAN RUSSIA)
Authors: Abadonova M. N.
Published: April 2024

The report contains data on the first record of Botrychium matricariifolium (Retz.) A. Br. ex W.D.J. Koch in the Oryol Region (Central European Russia). The information on the geographical location and species composition of the plant comunity is given, some morphometric features and the total number of individuals in the population are indicated.
MOSSES OF THE WESTERN PART OF THE CHUKCHI HIGHLANDS. 1. DISTRIBUTION BY HABITAT TYPES, AND ACTIVITY OF SPECIES
Authors: Kholod S. S. , Afonina O. M.
Published: April 2024

The analysis of the distribution of mosses in the landscape of the western part of the Chukchi Highlands served as the basis for distinguishing 12 types of habitats, which differ in a number of abiotic (altitude above sea level, slope exposure, steepness, degree of surface moisture) and biotic (composition of dominant species, cover of mosses and vascular plants, percentage of ground area free of vegetation) parameters. The vast majority of habitat types are the slopes of various steepness (including accumulative slopes – plumes with runoff hollows), which are characterized by active movement of solid matter. Each habitat type is characterized by its own moss composition, or bryocenotype. The species richness in the bryocenotypes varies from 23 (mountain slopes with moving scree) to 65 (sloping valleys of plumes with reservoir runoff), the lowest average number of species was found in the tormer bryocenotype – 2.63, the highest – 6.67 – was noted in floodplain terraces. Based on 322 geobotanical relevés, there were identified 12 bryocenotypes, i.e. aggregates of moss species of the same habitat type. Five classes of species activity have been distinguished, based on 3 parameters: the number of habitat types where the species has settled, the constancy of the species in one type of habitat, the cover of the species. Of the 122 moss species noted in geobotanical relevés, 5 oned are classified as especially active (Aulacomnium palustre, A. turgidum, Dicranum elongatum, Distichium capillaceum, Hylocomium splendens, Sanionia uncinata, Tomentypnum nitens), 11 are highly active, 24 are medium-active, 30 are low-active and 52 are inactive.
Response of Pinus sylvestris (Pinaceae) to Inbreeding, and Its Characterization as an Element of Incompatibility System
Authors: Kuznetsova N. F.
Published: April 2024

The results of the study of seed reproduction systems of Scots pine (Pinus sylvestris L.) under self-pollination and open-pollination are summarized (2- and 12-year experiment on self-pollination; electron microscopy). It was shown that in optimal years the generative sphere of pine is in equilibrium, with the populations being characterized by a minimum level of self-fertility (Rsf = 0.13–0.14). The ratio between self-sterile, partly self-fertile and self-fertile forms is 8ss : 4psf : 1sf, the proportion of inbred progeny is 7–8%. It was found that self-pollination partially reduces cone yield and increases the share of empty seeds. During self-pollination, the incompatibility of the self-sterile forms is ultrastructurally manifested in formation of the isolation zone at the border of pollen tube and nucellus, or of the embryo and endosperm. In early embryogenesis, the isolation zone between embryo and endosperm reaches a diameter of 1–2 cells, indicating the intensity of incompatibility processes. It has been shown that in slightly anomalous (cold or warm) and dry years the level of self-fertility increases in proportion to the strength of weather stress, and the sample structure changes. The share of inbred progeny increases from 1/12 in optimal years to 1/9, 1/5 and 1/3, in cold and warm, moderately dry and severely dry years, respectively. This confirms the participation of inbreeding in the adaptation of the seed gene pool to the habitat. The organization of the genetic incompatibility system in the pine and its changes in the transition from gymnosperms to angiosperms are discussed.
New Species of Freshwater Phaeophyta in Permian and Triassic of Siberia
Authors: Sadovnikov G. N.
Published: April 2024

The genus Mesenteriophyllum, described by T.A. Sistel in Kyrgyzstan and known in Australia and Antarctica, is revealed on the Taimyr Peninsula. The new species Mesenteriophyllum sixtelae with a transversely wavy thallus is described there. Morphologically similar plants were found in Central Siberia. The genus Kotchumdeckia is distinguished there, differing from Mesenteriophyllum by a flat thallus and a broad flattened marginal border. The newly described species Mesenteriophyllum sixtelae, Kotchumdeckia borutchinkinae, K. clavata, and K. parallela differ in the shape of the thallus. These plants belong to Phaeophyta. There are some Phaeophyta thalli overgrown with Cyanobionta.
NEW RECORD OF BUXBAUMIA VIRIDIS (BUXBAUMIACEAE) IN THE NORTH-WEST OF RUSSIA
Authors: Doroshina G. Ya. , Kurbatova L. E.
Published: April 2024

The moss Buxbaumia viridis, protected in Russia, was for the first time found in the territory of the North-West of Russia for the past 150 years. Data on the distribution of Buxbaumia viridis in Russia and Europe, as well as its phytocenotic confinement, biological features and accompanying species are discussed. There is a noticeable increase in the number of localities of this species in Europe, including in forests with significant human impact. Monitoring of the Buxbaumia viridis population in the territory of the reserve “Kurgalsky” is recommended, as well as the search for new localities.
ADDITION TO THE MOSS FLORA OF THE SOUTHERN KURILE ISLANDS (RUSSIAN FAR EAST)
Authors: Ignatova E. A. , Koroteeva T. I. , Fedosov V. E. , Ignatov M. S. , Kuzmina E. Yu. , Liksakova N. S. , Shkurko A. V. , Ezhkin A. K. , Kaganov V. V.
Published: April 2024

As a result of identification the moss collections from Shikotan, Kunashir, Iturup and Urup islands (Southern Kuril Islands, Russian Far East) collected by T.I. Koroteeva, V.E. Fedosov, A.V. Shkurko, N.S. Liksakova, and A.K. Ezhkin in 2015–2021, new species for the islands were revealed: 6 ones for Urup, 8 for Iturup, 10 for Kunashir, and 19 for Shikotan. For the first time, 4 species new for the Kuril Islands were discovered, including three new for the Sakhalin Region (Forsstroemia cryphaeoides, Haplocladium intermedium, Rhizogemma staphylina, Meteorium buchananii). Another 3 species found in the islands are new for the Southern Kuriles (Dicranum fragilfolium, Gollania turgens, Hygroamblystegium varium). Most of the discovered species are rare in both the Sakhalin Region and the Russian Far East. To date, the moss flora of the Southern Kurils numbers 468 species and is the richest bryoflora in Russia.
FEATURES OF ADSORPTION OF PARTICULATE MATTER BY NEEDLES AND LEAVES OF TREES IN IRKUTSK URBAN FORESTS
Authors: Mikhailova T. A. , Shergina O. V. , Mironova A. S.
Published: April 2024

The pollution of natural forests preserved on the territory of the Irkutsk city was studied in terms of the level of adsorption of aerosol particles (particulate matter, PMx) by main forest-forming species of woody plants. The needles of Scotch pine (Pinus sylvestris L.) and Siberian larch (Larix sibirica Ledeb.), as well as leaves of Silver birch (Betula pendula Roth) were sampled on the laid test plots to study their sorption capacity in relation to PMx. Using the methods of scanning electron microscopy and X-ray spectral microanalysis, a wide variety of shapes, sizes, and chemical composition of aerosol particles on the surface of needles and leaves was shown. The adsorbed PMx particles were found to contain carbon, silicon, sulfur, calcium, phosphorus, chlorine, and magnesium in the greatest amount; a significant proportion of heavy metals present in the form of metallized particle accumulations, in which the metal content can reach 80%. It has been shown that aerosol particles actively penetrate needle/leaf tissues through stomata and cuticle, damaging them. With a high level of pollution by PMx, complete clogging of the stomata and heavy destruction of dermal tissues are often observed. The high level of adsorption of particulate matter by needles and leaves of trees indicates a high cleaning capacity of urban forests. At the same time, pollution with PMx particles has a powerful negative effect on physiological and biochemical processes of a tree organism, which is manifested in a sharp violation of the parameters of photosynthesis, transpiration, and inhibition of growth processes.
XENOXYLON (CONIFERALES) FOSSIL WOODS FROM THE LOWER CRETACEOUS DEPOSITS OF THE FRANZ JOSEF LAND ARCHIPELAGO
Authors: Afonin М. А. , Gromyko D. V.
Published: April 2024

Fossil wood species Xenoxylon phyllocladoides and X. jakutiense of the Mesozoic genus Xenoxylon (Coniferales) are described from the Lower Cretaceous volcano-sedimentary deposits of Mac-Cult and Salisbury islands of the Franz Josef Land Archipelago. Fossil woods from Mac-Cult and Salisbury islands are described for the first time. Record of X. jakutiense from Salisbury Island represents the first record of this species from the island part of the Arctic. The presence of abietinean pitting on the radial walls of tracheids indicates that these species belong to the “phyllocladoides” group sensu Philippe et al. (2013), evolved from ancestral forms of Xenoxylon in the Early Jurassic. The discovery of  X. phyllocladoides and X. jakutiense fossil woods in the Lower Cretaceous deposits both on the island and mainland parts of the Russian Arctic confirms the conclusions about floristic links between Franz Josef Land and the northern part of the Siberian Platform in the Early Cretaceous.
SPECIFIC PROBLEMS OF GENOMIC DNA EXTRACTION FROM PLANTS: WAYS FOR SOLUTION
Authors: Galaktionova U. A. , Bolshakov V. N. , Tikhodeeva M. Yu. , Tikhodeyev O. N.
Published: April 2024

In modern botanical studies, various molecular genetic methods such as genome sequencing, PCR, AFLP-analysis, etc. are often involved. These methods require the use of high-quality (i.e. well purified and non-degraded) genomic DNA. However, extraction of such DNA from plants is complicated by a wide spectrum of organic compounds that contaminate DNA and drastically reduce its quality. As a result, the protocols for DNA extraction from plants are usually labor-intensive, time-consuming and require expensive reagents, most of which are imported from abroad. In the case of high-throughput DNA extraction from plant material, these disadvantages are of a great importance, especially in view of the current import problems. Moreover, there is no universal protocol suitable for all plant species and all variants of plant material used: different protocols are effective in different cases and additional modifications are often required. Promising ways to overcome these problems include the search for simplified methods of plant DNA extraction, as well as the use of specially prepared initial material.
ECOLOGICAL AND GEOGRAPHICAL CHARACTERISTICS OF THE DIATOM ALGAL FLORA IN THE ZEYA RIVER BASIN (AMUR REGION)
Authors: Medvedeva L. A.
Published: April 2024

The results of the study of freshwater algae communities in some watercourses located in the middle course of the Zeya River basin are presented. The annotated list of algae includes 245 taxa belonging to 232 species from 65 genera of Bacillariophyta. The characteristics of the algal flora in terms of habitats, relation to water salinity, saprobity of algae and their geographical distribution are given. Among the most interesting and rare species with a limited distribution ranges, there are Brebissonia boeckii, Cymbella amplificata, Cymbopleura stauroneiformis, Gomphonema angusticephalum, and Tetracyclus glans.
THE HERBARIUM OF MACROPHYTES OF THE A.O. KOVALEVSKY INSTITUTE OF BIOLOGY OF THE SOUTHERN SEAS OF RAS (SIBS), AND THE STAGES OF ITS FORMATION
Authors: Milchakova N. A. , Ryabogina V. G.
Published: April 2024

The paper presents the results of a retrospective analysis of the history of the formation of the macrophyte herbarium of Kovalevsky Institute of Biology of the Southern Seas of RAS (IBSS, Sevastopol, until 1963 – Sevastopol Biological Station, SBS). For the analysis, the electronic database of the herbarium, sources and archival materials published over a period of more than a hundred years, memoirs of the oldest employees of the SBS were used. Three stages of the herbarium fund formation were distinguished, its beginning dating back to 1878. The first herbarium specimens were collected and designed by S.M. Pereyaslavtseva, the first Russian female zoologist and the first head of the SBS. According to archival data, by the beginning of the World War II, the herbarium contained about 3 000 herbarium sheets; like all museum collections of the SBS, it burned down in 1942. The beginning of its restoration dates back to 1945, today it contains 30914 sheets of 715 species and 198 genera from 734 localities, it is included in the international herbarium database Index Herbariorum (its acronym is SIBS). The paper summarizes the data on collection sites in the Atlantic, Arctic, Pacific, Indian and Southern Oceans. The historical collections of famous algologists N.V. Morozova-Vodyanitskaya (collection from 1920 to 1931) and A.A. Kalugina-Gutnik (from 1960 to 1991), and of a collector of the Karadag Biological Station G.M. Stanilovsky (from 1924 to 1946) are characterized; they account for 71% of the total volume of the fund. It is shown that the key macroalgae of the Black Sea are represented by collections for more than half a century from the same locality (Phyllophora crispa (Hudson) P.S. Dixon, Ericaria crinita (Duby) Molinari et Guiry, Gongolaria barbata (Stackhouse) Kuntze, Ulva rigida C. Agardh, etc.). There are unique macroalgae specimens from the underwater uplifts of the Mediterranean Sea, 14 islands and atolls of the Seychelles archipelago, the islands of Antarctica, of the seagrasses of the Indian Ocean, whose localities are not found in the herbaria of the world. To expand access to the herbarium fund, it is necessary to export data to the global bank and the global biodiversity information system (GBIF). On the basis of the studies performed, a rationale was prepared of naming the herbarium of macrophytes of world ocean IBSS after A.A. Kalugina-Gutnik (1929–1994), taking into account her significant contribution to the preservation of scientific heritage and traditions, and the creation of the collection fund.
DEVELOPMENT OF FLOATING KARST MIRES IN THE NORTH-EASTERN PART OF THE MIDDLE RUSSIAN UPLAND, AND CARBON ACCUMULATION IN PEAT DEPOSITS
Authors: Volkova E. M. , Leonova O. A. , Zatsarinnaya D. V.
Published: April 2024

The floating karst mires are unique natural ecosystems of the Middle Russian Upland, since they are habitats of rare species and communities in the region with low paludification (0.5%), and also participate in the deposition of atmospheric carbon. The study of the genesis of the floating karst mires will allow to develop approaches to their conservation.
The purpose of this work is to identify the features of development and to estimate the intensity of carbon accumulation in the peat deposits of the floating mires of the Middle Russian Upland. The objects of the study were the mires Glavnoe and Kochaki-1, located in the north-eastern part of the Middle Russian Upland. To identify the genesis of the mires, the peat deposits were drilled and the botanical composition of peat was studied. The carbon content (%) was determined in peat samples and the rate of carbon accumulation by mire paleocenoses was calculated.
The conducted studies have revealed different types of paludification in karst depressions, accompanied by the formation of a float, depending on a hydrological regime. It is shown that the most active vertical growth of peat deposits occurs in conditions of high moisture content of mire biotopes. This contributes to the maximum accumulation of atmospheric carbon by mire paleocommunities (up to 79.3–125 gC/m2/year). The highest carbon deposition rates are characteristic of the sphagnum and herb-sphagnum paleocenoses (up to 151–305 gC/m2/year) formed on the floats in the second half of the Subatlantic Holocene period. The results obtained indicate the diversity of the genesis of the floating mires and characterize these ecosystems as a “depot” of atmospheric carbon.