bluuebunny/crossref_metadata_2025 huggingface dataset:
Part of anti-covid therapy based on a theoretical model describing mechanics of contact interaction between coronavirus and cell membrane
Authors: Koltcova N. A
Published: April 2024

This article proposes a theoretical model of mechanical feedback in pattern formation on deforming a membrane when coronavirus enters a cell. Coronavirus stiff and flexible spike proteins attach to ACE2 receptors on the cell membrane of the target cell. TMPRSS2 triggers the fusion of the viral and cell membranes with the formation of a fusion pore leading to opening of a capsid surrounded by the coronavirus envelope and viral RNA release into the cell. Based on mechanical feedback analysis of contact interaction and elastic shell theory, a critical value of cell radius, at which a fusion pore is formed and membrane damage occurs locally, is determined. The results revealed that the smaller the cell size, the less likely that the cell will be damaged mechanically when exposed to the virus. One of the ways to reduce the cell size is to decrease intracellular fluid volume through the use of medicines - diuretics. The critical value of cell radius is inversely proportional to the value of binding energy at the time of attachment of the coronavirus to the cell membrane. Further research is required to improve our knowledge of the dependency of binding energy on the shape and sizes of spikelike bumps for various types of coronavirus strains. It may be predicted that when a new coronavirus strain will emerge, it may produce lower binding energy to cell surface and the severity of the disease may decrease. It is necessary to verify the conclusions of the theoretical study by experimental methods.
Dinitrosyl iron complexes with thiol-containing ligands as sources of universal cytotoxins - nitrosonium cations
Authors: Vanin A. F , Tkachev N. A
Published: April 2024

It was shown that the release of a half of nitrosyl ligands from dinitrosyl iron units in the form of nitrosonium cation (NO+) from binuclear dinitrosyl iron complexes with thiol-containing ligands (B-DNIC) during DNIC decomposition in acid solutions is increased with the decrease of the stability of these complexes and completely blocked with the increase of the concentrations of free thiols (non-included into B-DNIC) up to the level that was two times and more than that of dinitrosyl iron units. It was demonstrated that the less stable B-DNIC with mercaptosuccinate degrade in an acidic environment at ambient temperature, while the decomposition of more stable B-DNIC with glutathione was only marked when the solution was heated at 80°C. The inhibition of NO+ release from B-DNIC in the presence of elevated free thiol level in the solution was due to the ability of free thiols to induce the reduction of NO+ to NO.
Evaluation of the efficiency of intersystem crossing to a triplet state of fullerene in complexes with amino acids
Authors: Buchelnikov A. S , Sokolov P. A , Ramasanoff R. R
Published: April 2024

The important photophysical process that determines the efficiency of photosensitizers is saturation of a triplet state by intersystem crossing during light absorption. In the present work, C60 fullerene complexes with amino acids glycine, lysine, methionine and threonine were studied as promising photosensitizers. All these complexes, for which the calculations were done, demonstrate high values of rate constants of transition to triplet states and a high probability of the ability to generate reactive oxygen species through excitation in the visible spectrum. The carboxyl groups of amino acids that are not involved in electronic excitation can be used as the component of specific DNA aptamers for conjugation to photoactive complexes for a tumor-targeting drug delivery system.
The organic osmolyte betaine effectively counteracts the deleterious effect of diclofenac on protein structure and stability
Authors: Basheeruddin M. , Ahmed N. , Khan Kh. A , Jamal Sh.
Published: April 2024

Understanding the physicochemical properties of pharmacy and the concept of pharmacophore is essential to devise guidelines for the synthesis of target-oriented drugs. In the present study, thermal denaturation, circular dichroism, intrinsic fluorescence, and docking were employed for studying the effects of the non-steroidal anti-inflammatory drug, diclofenac sodium, on the stability and structure of bovine pancreatic ribonuclease (RNase A) taken as a model of an enzyme. Since drug-protein interaction is an important pharmacokinetic parameter of a drug, it was deemed significant to study the effects of diclofenac on protein structure and stability. When the thermodynamic parameters were assessed, it was shown that RNase-A was destabilized in the presence of diclofenac sodium in terms of Tm and ΔGD°, while the addition of osmolytes stabilized the protein. In the presence of diclofenac sodium and osmolyte, there was a change in a tertiary structure of the protein but not in its secondary structure. Spectral results revealed a decrease in fluorescence intensity confirming fluorescence quenching of RNase-A by diclofenac sodium and osmolytes. Molecular docking analysis suggested that hydrogen bonds and Van der Waals are involved in the binding of RNase-A to diclofenac sodium. The RNAse-A activity is decreased in the presence of diclofenac sodium while osmolyte can restore the RNase-A activity and the indices kcat increase and Km values decrease. This study presents new combination of drug therapy comprising diclofenac sodium and osmolytes to reduce the risk of adverse effects of diclofenac sodium.
Influence of laser radiation of a surgical laser on the structure of bovine serum albumin molecules in vitro
Authors: Serov D. A , Nagaev E. I , Kuleshova A. I , Reut V. E , Astashev M. E
Published: April 2024

The influence of laser radiation of a surgical laser on the physicochemical properties of bovine serum albumin molecules was studied. After exposure to laser radiation, the optical density of protein solutions increases, the fluorescence intensity decreases, a significant decrease of the intensity of the a-helix band on the Raman spectrum is observed and the refractive index of protein solution did not significantly change. However, the viscosity increased, and the pseudoplasticity of aqueous solutions of albumin decreased. There was no massive damage to the protein polypeptide chain, on the contrary, intensive aggregation was observed. Thus, in a bovine serum albumin solution subjected to contact action of laser radiation, the processes of partial denaturation and aggregation prevail, aromatic amino acid residues of the protein are damaged to a lesser extent, and fragmentation of albumin molecules is not observed.
Identification of pathogenic bacteria using the spectra of native DNA molecules
Authors: Ikhlov B. L
Published: April 2024

The purpose of detecting low-frequency (relative to infrared and ultraviolet) resonance absorption of an electromagnetic field in the centimeter wavelength range using DNA molecules at a frequency corresponding to the natural frequency of torsional vibrations of the native DNA helix is to find a relationship between the length of DNA (its spectrum) and the type of a bacterium. Instead of DNA solution, cultures of different bacteria that contained DNA were used and the resonance frequencies of torsional vibrations of the helices in DNA molecules were calculated for them. The cultures were placed in test tubes or in a cuvette and were subjected to microwave irradiation. Theoretical analysis was carried out with respect to the DNA reaction to external centimeter radiation and the resonant DNA frequencies of three types of bacteria such as E. coli M17, M. avium and Mycobacterium tuberculosis were determined. Peak absorption of the ultrahigh-frequency electromagnetic field by bacterial cultures was detected at frequencies close to the calculated natural frequencies of torsional vibrations of DNA helices of the said types of bacteria: 10.271 GHz, 10.317 GHz and 10.356 GHz, respectively.
Analysis of coverage of Alu repeats by aligned genomic reads
Authors: Tamazian G. S , Kanapin A. A , Samsonova A. A
Published: April 2024

Alu repeats occupy a notable part of the human genome and greatly affect processes related to genome integrity maintenance. One of the basic methods for studying variation in a genome, including Alu repeats is genome sequencing followed by mapping the sequenced reads to a reference genome sequence. The key feature of the read alignment is the depth of reference genome region coverage by mapped reads. In this paper, a new method is proposed for analyzing the coverage of Alu repeats and their flanking regions by whole-genome sequencing reads and the distribution of mean coverage in two aforementioned region types is explored.
Physiological role of slow sodium channels in primary sensory coding
Authors: Skrebenkov E. A , Krylov B. V , Vlasova O. L
Published: April 2024

Nav1.8 sodium channels of nociceptors participate in encoding signals generated by polymodal nociceptors and only the high-frequency component of this impulse response alerts the brain to tissue damage and provides information about the location and type of pain. Specific reduction of the functional activity of these channels should help in “switching off” this high-frequency component, hence, the possibility of retaining the normal functioning of polymodal mechanoreceptors, thermoreceptors, and chemoreceptors in case of chronic pain. From general medical practice, it is known that in the treatment of pain, there are no safe analgesics, the use of which as a long-term therapy would be completely safe. Mathematical modeling based on the Hodkgin and Nuxley formulation describing the flow of ionic currents was used to understand the mechanism of specific modulation of the functional activity of Nav1.8 channels and its role in primary sensory encoding of nociceptive information. This mechanism is based on a reduction in the potential sensitivity of these channels due to a decrease in the effective charge transferred by their activation gating structure. It is shown for the first time that this leads to a complete restoration of the normal function of the stimulus-response of the nociceptive neuron. At the same time, only the high-frequency component of its membrane response is specifically eliminated. The same effect can be achieved by reducing the density of slow sodium channels. However, it is obvious that in the second case, the action of pharmacological substances which are supposed to be called analgesics will be less specific since the interaction with other representatives of the superfamily of sodium channels might turn out to be feasible.
The dynamics of biophysical characteristics of the northern Black Sea pelagic ecosystem in the first decades of the XXI century
Authors: Piontkovski S. A , Serikova I. M , Minsky I. M , Zagorodnyaya Yu. A , Suslin V. V , Kovaleva I. V
Published: April 2024

Wind speed, sea surface temperature chlorophyll-a concentration (satellite data such MODIS-Aqua/Terra), bioluminescence intensity and zooplankton biomass (data from the research vessel), the value of fish traded, the indices of lower-than-normal atmospheric pressure and water mass transfer (model calculations) are the factors used to estimate a modern state of the pelagic ecosystem and its functional characteristics. It has been shown that, in the last two decades (2000-2020), after natural cataclysms associated with eutrophication and trophic stress of invasive plankton species in the 1990s, the ecosystem of the open areas in the northern portion of the Black sea has reached a state of relative stability in its structure and functioning. This state is characterized by the absence of changes in the interannual variability of the factors particular for it. Concepts are discussed which concern regional differences in physical factors and biological interactions over many years.
Salts of short-chain fatty acids increase the activity of the large conductance, Ca2+-activated K+ channels and reduce calcium oscillations in rat GH3 cells
Authors: Shaidullov I. F , Ermakova E. V , Sorokina D. M , Yakovleva O. V , Sitdikova G. F
Published: April 2024

The short-chain fatty acids such as acetic, propionic and butyric acids are microbiota metabolites that can exert a series of physiological effects both in the intestine and other organs, including the central nervous system. The present work aimed to examine the effects of sodium acetate, propionate, and butyrate on the activity of large conductance Ca2+ activated K+ channels and calcium oscillations in rat pituitary GH3 cells. It has been shown that fatty acids under study cause a dose-dependent increase in the amplitude of total outward potassium currents and these effects are prevented by tetraethylammonium, a Ca2+ activated K+ channel blocker, indicating the involvement of Ca2+ activated K+ channels in the effects of fatty acids. It is worthy of note that fatty acids increased open probability of single channels with no changes in the amplitude and the mean channel open time. In addition, fatty acids were associated with a significant reduction in the amplitude and frequency of Ca2+ oscillations in GH3 cells. An increase in potassium conductance and a decrease in the intracellular Ca2+ level can mediate the effects of short-chain fatty acids in various excitable structures, such as a relaxation of intestinal and vascular smooth muscle cells, hyperpolarization of neurons, and the regulation of hormone and neurotransmitter release.
Bioluminescence of ctenophore Pleurobrachia pileus (O.F. Muller, 1776) in the summer period
Authors: Temnykh A. V , Silakov M. I , Mashukova O. V
Published: April 2024

The capability of bioluminescence has been found in many marine hydrobionts, including almost all representatives of the phylum Ctenophora. The glow of species and bioluminescent substrates isolated from them is actively used in biology, ecology, and medicine to study the physiological state of an organism or to identify unfavorable environmental parameters. The parameters of luminescence of the Black Sea ctenophores Mne-miopsis leidyi A. Agassiz, 1865 (Lobata) and Berce ovata Bruguicre, 1789 (Beroida) are used to study the effects of toxicants, such as liquid hydrocarbons, PCBs, and heavy metals. Some researchers casted doubt on the capability of the Black Sea autochthonous inhabitant, ctenophore Pleurobrachia pileus (O. F Muller, 1776) to produce bioluminescent light. The objective of this work was to ensure scientific support for the light-producing ability of species under study and to choose the optimal time for conducting experiments on the factors that affect bioluminescence. It was found that mechanical and chemical stimulation triggered a bioluminescent response in all size groups of species under study at any time of day. Upon chemical stimulation of the studied species, the signal energy value was several times greater than that observed after mechanical stimulation. It was revealed that the optimal time interval for conducting biophysical research is the time from 8 pm to 6 am, because the values of luminescence activity are the greatest in this time interval within a day.
On biophysics and a chair of biophysics at the faculty of physics of Moscow State University
Authors: Tverdislov V. A , Lobyshev V. I , Yakovenko L. V , Gapochka M. G
Published: April 2024

A historical timeline created to celebrate the 63-year anniversary of a chair of biophysics, the first in the world of science chair founded at Lomonosov State Moscow University. Professor Lev Alexandrovich Blumenfeld and Professor Simon El’evich Shnoll, who both departed this life in 2002 and 2021, respectively, started the chair. In the latest issues of journal "Biophysics", a large series of articles written and prepared by friends, colleagues, students, and the successors of these outstanding scientists have been published. This article closes this series. The article includes a brief historical overview of the formation of world and Russian biophysics as a scientific discipline, gives information about the history of how the Chair of Biophysics has been established, its main achievements and the scientific schools formed within the walls of this Department.
Conformational particularities of beta-amyloid peptide 25-35
Authors: Agaeva G. A , Najafova G. Z
Published: April 2024

In Alzheimer's disease, beta-amyloid peptide (Ав) plays an important role in the mechanism of neurodegeneration. A small fragment of Лв(25-35) (with the sequence GSNKGAIIGLLM) is regarded to be the functional domain of Лв, responsible for its neurotoxic properties and represents the biological active region of Лв. Conformational analysis of each C-terminal segment of the peptide by the method of molecular mechanics revealed a limited number of most probable conformations and quite clearly helped to clarify what forces stabilize the structures. The obtained results showed that Лв(25-35) energetically has a propensity for adopting alpha-helix conformation of the C-terminal octapeptide segment. A molecular dynamics method was used to build a model of intramolecular mobility in the Лв(25-35) molecule. It was demonstrated that in low-energy conformations, Лв(25-35), the orientation of flexible structures of the N-terminal region with respect to the structures of the C-terminal region is different.
Effect of combined use of melatonin and diethyldithiocarbamate on the N1E-115 cell line (a clone of cells from mouse neuroblastoma C-1300)
Authors: Myakisheva S. N , Baburina Y. L , Kobyakova M. I , Krestinin R. R , Sotnikova L. D , Krestinina O. V
Published: April 2024

A study has been made on the effects of sodium diethyldithiocarbamate and melatonin and their interaction on proliferative activity, the variation in cytosolic Ca2+, membrane potential and reactive oxygen species production in the neuroblastoma N1E-115 cell line (a clone of cells from mouse neuroblastoma C-1300). This study showed that combined use of diethyldithiocarbamates and melatonin inhibited proliferation and enhanced cell differentiation. At the same time, the content of Bcl-2 decreased, while the content of Bax increased, that were likely to trigger an apoptotic cascade. However, the use of these two drugs in combination did not enhance the observed effects. Therefore, this study suggests that the mechanisms by which diethyldithiocarbamates and melatonin act are apparently different.
Comparative cytotoxic activity of lutein or cisplatin doped with liposomes against breast cancer cell lines after radiotherapy
Authors: Lafta R. A , Shafaa M. W , Darwish W. M , El-nagdy M. S
Published: April 2024

Interactions of the anticancer drug cisplatin or the antioxidant drug lutein with liposomes as model membranes were characterized. All liposomes had the almost spherical shape, taking into account that lyposomes without the said drugs were more evenly dispersed and tended to aggregate less. The mean size diameter of empty liposomal samples was 617.90 ± 75.64 nm, while liposomes loaded with cisplatin, lutein and a cisplatin+lutein combination were 425.60 ± 64.74 nm, 877.85 ± 93.90 nm and 189.91 ± 136.84 nm, respectively, in diameter. The incorporation of cisplatin or lutein into liposome membranes resulted in an increase in the zeta potential values. The lowest zeta potential value was achieved in lyposomes containing cisplatin in combination with lutein. The addition of cisplatin to liposomes caused a shift in the melting temperature towards higher values than those of the main peak of empty liposomes indicating a conformational disorder within the phospholipids. Encapsulation of lutein into liposomes resulted in the disappearance of the main characteristic endothermic peak of pure liposomes. FTIR spectroscopy confirmed the interaction of lutein or cisplatin with functional groups in liposomes. In the absence of external gamma-irradiation, the IC50 value for free lutein in the cytotoxic assay with MCF-7 treated cells was 10.62 gg/ml, while free cisplatin showed the IC50 value of 41.02 gg/ml. IC50 was 65.84 gg/ml and 34.29 gg/ml for nanoliposomal lutein and cisplatin, respectively. Using the combined therapy of gamma irradiation at dose rate 5 Gray followed by 10 Gray, the IC50 value for free lutein changed from 17.0 to 9.5 gg/ml. IC50 for free cisplatin changed from 51.00 to 43.09 gg/ml. This study showed that cytotoxic effect of a standard form of lutein is stronger than that of nanoliposomal lutein. The current evidence reveals a new regimen for the treatment during which replacing cisplatin with free lutein increases anticancer activity against the MCF-7 cancer cell line.
Proteostasis of heat shock protein 90 in skeletal muscles of the long-tailed ground squirrel during hibernation
Authors: Gritsyna Yu. V , Popova S. S , Mikhailova G. Z , Bobyleva L. G , Udaltsov S. N , Morenkov O. S , Zakharova N. M , Vikhlyantsev I. M
Published: April 2024

We investigated changes in the content of heat shock protein 90 in m. soleus (comprised of mainly fibers expressing the MyHC slow isoform I) and m. gastrocnemius (composed of mainly fibers expressing the MyHC fast isoforms II) of the long-tailed ground squirrel Urocitellus undulatus in different periods of the annual cycle: summer activity (seasonal control), hypothermia/torpor, winter (interbout) activity. The content of the protein in both muscles was found not to change throughout the entire hibernation period despite the development of atrophic changes, more pronounced in fast m. gastrocnemius. The role of HSP90 in maintaining the stability of giant sarcomeric titin protein molecules is discussed with reference to animal's entry into and exit from hypothermia, when the activity of calpain proteases increases due to the increased content of Ca2+ in the cytosol of muscle cells; and with respect to the torpor, when the activity of calpains is, most likely, not inhibited completely. During the interbout activity with an observed increased titin turnover in squirrel's striated muscles, a constant content of HSP90 appears to be required for the correct folding of newly synthesized titin molecules and their integration into sarcomeres, as well as for the removal of misfolded titin molecules and other proteins. Thus, HSP90 proteostasis in skeletal muscles of the long-tailed ground squirrel can contribute to maintaining a steady-state level of titin and, possibly, other sarcomeric proteins during hibernation, which, in turn, will contribute to maintaining a highly ordered sarcomeric structure and the necessary level of muscle contractile activity in different phases of the torpor-arousal cycle.
Modeling the critical fliker fusion frequency in the human visual system
Authors: Lyapunov S. I , Shoshina I. I , Lyapunov I. S
Published: April 2024

The temporal resolving power of the visual system is essential for the perception of the objective world. The lowest sampling rate of a sequence of images at which perception becomes fused is called the critical flicker fusion frequency. The variety of experimental data on critical frequency thresholds can be explained from a point of view of a model of the contrast sensitivity of the visual system that based on the tremor modulation signal. The model describes the dependence of critical frequency on stimulus brightness, adaptation brightness, duration, and the angular size of the stimulus. This model demonstrates that for bright stimuli with short duration and a large angular size, critical frequency values lie in the range up to 1000 Hz; the frame rate of 300-500 Hz should be considered optimal for the visual system; for small-sized angular stimuli, the critical frequency lies in the low-frequency region. Differences in the rate of flicker fusion can be explained by temporal sensitivity of magno- and parvocellular neurons.
A complex system of the mouse brain - selection for successful solution of a cognitive test
Authors: Poletaeva I. I , Perepelkina O. V , Zorina Z. A
Published: April 2024

The study provides a review of experimental research on selection of mice that yields positive results. The selection of mice was high (the task required mice to understand that an object which has become invisible, still exists and could be found) and poor performance in a cognitive test. The results obtained revealed better short term memory in mice, selected for high performance scores, and that these mice also showed higher performance in tests for novelty and attention. This suggests that differences between mice used in the experiment are associated not only with cognitive abilities in tests, but also with more pronounced “executive functions”.
Mechanism of the cytotoxic effect of noble metal polyacrylates on tumor cells
Authors: Chigasova A. K , Ostrovskaya L. A , Korman D. B , Bluhterova N. V
Published: April 2024

The present study was carried out to investigate and compare the cytotoxic activities and mechanism of action of gold polyacrylates (aurumacryl) and silver polyacrylates (argacryl) using human tumor cell line (MCF-7 cell culture). The tested compounds showed high cytotoxic activity. It was found that argacryl is 20 times more effective than aurumacryl. It was established that apoptosis represents the dominant mechanism by which tumor cells undergo cell death induced by aurumacryl and argacryl. Differences in the effect of drugs on the DNA structure in tumor cells were found.
Analysis of the relationship between the activity of the reticular formation of the medulla oblongata, respiratory and cardiovascular systems in rats under painful stimulation
Authors: Dick O. E
Published: April 2024

Using the method for calculating the average of conditional probabilities of recurrence intervals, a comparative analysis was performed to estimate the direction of coupling between different physiological rhythms in the form of fluctuations in blood pressure, respiration, and the activity of neurons in the reticular formation of the medulla oblongata in two groups of anesthetized rats under pain stimulation or no stimulus. It was found that there are different kinds of the directions of coupling between the analyzed rhythms. Most of the data obtained for rats from the control group and rats with experimentally induced colitis suggest the statistically significant unidirectionality of coupling. Painful stimulation did not affect the direction of coupling, but the amount of data on unidirectionaity of coupling slightly reduced. At the same time, the rhythms associated with the cardiovascular system (blood pressure variability) were controlled by the rhythms of the respiratory system, and the respiratory rhythm controlled the variability of the activity of neurons in the reticular formation of the medulla oblongata.
Meta-analysis of randomized clinical trials on the speed of pulse wave propagation
Authors: Gharamyan B. G
Published: April 2024

This paper presents a theoretical analysis of the literature on the speed of pulse wave propagation using a combination of ECG and PPG signals. The diagnostic value of pulse wave velocity in medical practice is use of this indicator for non-invasive measurement of blood pressure and also for determination of arterial stiffness. Some studies have shown an association of pulse wave velocity with risk factors for cardiovascular disease. The speed of pulse wave propagation is an early marker and predictor of cardiovascular risk both in individuals with normal blood pressure and people with hypertension and is used as the "gold standard" for assessing arterial stiffness; however, the question about accuracy and automation of the measurement of the speed of pulse wave propagation still remains to be answered.
Piezopulsometric analysis of the functional state of human cardiovascular system
Authors: Nesterov V. P , Burdygin A. I , Ivanov K. B , Sobol K. V , Shemarova I. V
Published: April 2024

This paper expounds how to apply in practice the developed computer method of arterial piezopulsometry, with examples, for non-invasive express analysis of the functional state and the nature of autonomic regulation of the cardiovascular system in patients of different ages and health conditions. The participation and role of the contractile component of myocytes of the left ventricle of the heart is assessed as a universal muscle effector, providing both the basic pumping function of the heart and the implementation of the autonomic regulation of heart contraction using peripheral neurohumoral mechanisms that maintain the optimal level of cardiac hemodynamics. This analysis enhances the predictive value of early non-invasive pulsometric diagnostics of the individual functional state and nature of regulation of human cardiovascular system during ontogenesis. This knowledge helps identify the risk of reducing the ability of the cardiovascular system, which has developed during its evolution, to maintain dynamic balance, self-regulation and adaptation to changing environmental conditions, which is associated with a violation of the body’s homeostasis.
SEXUAL POLYMORPHISM OF RANUNCULUS ACRIS (RANUNCULACEAE) IN THE MOSCOW REGION
Authors: Godin V. N.
Published: April 2024

The gynodioecy of the polycarpic Ranunculus acris L. was studied in the Moscow Region. This plant has three types of flowers that differ in androecium structure: perfect flowers (with fertile stamens and carpels), partially male-sterile ones (some of the stamens become staminodes to form sterile pollen), and pistillate ones (an extreme reduction of stamens and the complete absence of fertile pollen). These three types of flowers form a size gradient from the largest perfect to the smallest pistillate ones. Each flower type is formed on separate plants. The share of plants with perfect flowers in 10 studied coenopopulations varied from 43.9 to 53.0%, that of the plants with partially male-sterile flowers from 45.5 to 54.4%. Plants with pistillate flowers are extremely rare (1.5–2.0%). Over three years of observations (2020–2022), we found that the sexual forms of the plants did not change the sex of their flowers, and the sex ratio in the coenopopulations remained stable, without significant fluctuations.
MONITORING OF VEGETATION IN PALUDIFYING SMALL LAKES IN THE LOMONOSOVSKY DISTRICT OF THE LENINGRAD REGION
Authors: Smagin V. А. , Boychuk М. А.
Published: April 2024

The results of the vegetation monitoring in two paludifying lakes in the Lomonosovsky District of the Leningrad Region are reported. The paludification is triggered by a decline in the water level provoked by forest drainage melioration in the late 20th century. The vegetation of the lakes was first studied by V.А. Smagin in 1982–83, and was re-examined in 2004, 2014 and 2020. The composition of the bryoflora in the descriptions of 2014 and 2020 was determined by М.А. Boychuk. During the period of research, the successions were noted in lakeside mires, which led to the formation of the vegetation typical of lakeside mires. The vegetation lost its original mosaic and became more or less uniform throughout the profile, hardly distinguishable from “natural” lakeside mires. Meanwhile, in a number of places, the formation of a tree layer was noted. Beavers settled along the shores of the studied lakes, with various consequences. At one lake, the settlement of beavers turned out short-term and had no consequences, at the second one it was longer and affected the direction of successions and changes in the surrounding landscape.
TYPOLOGY OF TERRITORIAL VEGETATION UNITS ON THE EXAMPLE OF THERMOKARST MASSIFS ON KOTELNY ISLAND (NEW SIBERIAN ISLANDS)
Authors: Sumina O. I.
Published: April 2024

In the Arctic, permafrost and underground ice melting is one of the modern problems that requires constant monitoring. In the areas with spreading thick ice-wedge polygonal networks, the territories occupied by groups of mounds separated by trenches formed in the place of melted ice veins are a widespread result of thermokarst. The vegetation of such territories (referred to as massifs) is represented by territorial units of the first hierarchy levels with an intra- (mosaic of patches within communities) and supraphytocoenotic (micro- and mesokombinations: complexes, their aggregates and series) heterogeneity. The shape, size and vegetation of the mounds and trenches change under the influence of thermal denudation, and the vegetation of a whole massif also changes, so it can serve as an indicator of thermokarst intensity. The relief formed by thermokarst is typical of the landscapes of New Siberian Islands. According to the descriptions of 38 massifs made on Kotelny Island in 1974–1975, they were for the first time typified as territorial units of vegetation. In total, 7 types of massifs belonging to 2 classes are identified and characterized: baidzharakh massifs proper (with mineral mounds) and massifs with peat mounds (including 1 type of massifs). The first class comprises 2 groups of types: weakly differentiated massifs (microcombinations) and differentiated massifs (mesocombinations). In the first group, there are 2 types of massifs, in the second one – 4 types. Six distinguished types of baidzharakh massifs correspond to successive stages of massif transformation (a scheme is given). The heterogeneity of massif vegetation becomes more complicated with time, and becomes simpler again, when the massif is destroyed. Embryonal massifs are represented by microcombinations, a group of developed (differentiated) massifs – by mesocombinations, collapsing massifs – by microcombinations. The developed typology of the baidzharakh massifs as territorial vegetation units is convenient for practical work and using in monitoring and comparative assessment of thermokarst intensity in the Arctic areas with different flora and vegetation.
FINDING OF UROSPORA WORMSKIOLDII (CHLOROPHYTA, ULOTRICHACEAE) IN THE WHITE SEA
Authors: Berezina М. О. , Mikhaylova T. A.
Published: April 2024

The article deals with the first finding of Urospora wormskioldii in the White Sea. Information on the morphology of U. wormskioldii and the conditions of its growth is presented. The species entry into the White Sea is discussed.
OVERVIEW OF TECHNIQUES TO PREPARE LIGHT MICROSCOPIC MOUNTS OF HELIANTHUS (ASTERACEAE) REPRODUCTIVE STRUCTURES
Authors: Babro A. A. , Voronova O. N.
Published: April 2024

There are many investigations concerning material processing and staining of permanent or temporal mounts for light microscopy, and there are many works on Helianthus embryology either with the description of the methods or without it. Our aim was to make a review of these methods and to customize existing methods of permanent and temporal mounts staining for the work with representatives of the genus Helianthus to get good quality photo images.Wild perennial species Helianthus ciliaris, H. tuberosus, H. maximilianii, as well as cultivated forms of annual sunflower H. annuus were included in our research. The most of methods were worked out on H. ciliaris, and then were successfully used in the work with other Helianthus species listed above.When following classical methods, some stains become very pale or wash out completely during processing of the sunflower mounts. We developed some practices to avoid these failures. They are: prolongation of stains exposure; staining at higher temperature; reducing the time of processing by ethanol, acetic acid and other substances that can wash out the stain; changing the order of stains exposure; changing the way of mounts dehydration (drying in thermostat instead of treatment by absolute ethanol).We found out optimal techniques for staining of male and female reproductive structures of sunflower and the methods suitable for all structures: toluidine blue, Schiff’s reactive with alcian or toluidine blue as counter-stains, safranin with alcian blue. It is convenient to use acetocarmine solution for the estimation of sunflower pollen viability.Chloral hydrate, methyl benzoate or “Bio Clear” solution are applicable reagents for clearing ovules. The material after chloral hydrate or methyl benzoate is satisfactory to embed in paraffin and to make permanent mounts.
USE OF PHYTO-INDICATION METHODS IN ASSESSMENT OF RELATIONSHIP OF NITROGEN CONTENT IN PLANTS WITH THEIR GROWING CONDITIONS (ON THE EXAMPLE OF FORESTS IN THE SOUTHERN MOSCOW REGION)
Authors: Zubkova Е. V. , Stamenov M. N. , Priputina I. V. , Grabovsky V. I.
Published: April 2024

The relationship of the chemical composition of plants with conditions of their growth and their contribution to soil nitrogen during dying is revealed. The study was based on the materials of geobotanical relevés of 15 forest plots in the subzone of coniferous-deciduous forests in the south of the Moscow Region. Two methods of phytoindication were used. The type of habitat conditions was determined according to the Vorobyov-Pogrebnyak’s indicator species. The point values of soil nitrogen richness were calculated according to the Tsyganov’s scale. The nitrogen content in plant organs, samples of forest litter and soil was determined using gas chromatography. The analysis of the data showed a correlation between the types of forest vegetation conditions and the points on the Tsyganov’s nitrogen richness scale for the conditions of the southern Moscow Region. The nitrogen content in the forest litter has a high reliable relationship with the types of habitat conditions. It is shown that plants from the habitats which are richer in nitrogen according to the Tsyganov’s nitrogen richness scale have a higher nitrogen content in leaves, stems and rhizomes than plants growing in poorer soil conditions. The conducted study has shown the validity of using phytoindication scales for the assessment of soil conditions.
PHYTOPLANKTON IN THE LAKES OF THE REPUBLIC OF BASHKORTOSTAN
Authors: Belyaeva P. G.
Published: April 2024

The phytoplankton in a number of lakes in the Bashkir Trans-Urals (Atavdy, Sultankul (2017), Bursunsy, Kuldybay (2019), Bolshiye Uchaly, Uzunkul (2021)) and Bashkir Pre-Urals (Bolshoy Tolpak, 2022)) was studied. As a result of the study, the taxonomic structure, quantitative characteristics, dominant species, distribution features of main algal groups were reveald, and their ecological and geographical characteristics werre identified. 257 species and intraspecific taxa of algae from 9 divisions were registered in the algal flora. Green algae (33%), cyanoprokaryotes and diatoms (21% each of total species number) show the highest species diversity in the lakes. The algal flora is specific for each lake and has low degree of floristic similarity (0.13–0.57 according to Sørensen coefficients). In the ecological and geographical terms, the algal floras of lake plankton is represented by typical planktonic species, widespread in waterbodies of the globe, indifferent to water salinity, living only in fresh waterbodies and preferring neutral waters. Quantitative indicators of phytoplankton varied in a wide range of values: number of cells from 4.4 to 344 mln cells/L, biomass from 0.23 to 22.97 mg/L. Dominant species in terms of abundance are represented predominantly by cyanoprokaryotes (Snowella lacustris, Aphanocapsa delicatissima, A. incerta, Aphanizomenon flos-aquae, Gloeotrichia echinulata, Merismopedia tenuissima, Pseudanabaena galeata, Planktolyngbya limnetica, Woronichinia compacta, Anathece clathrata, Rhabdoderma lineare), in terms of biomass by green (Oocystis lacustris, O. borgei, O. marssonii, Scenedesmus apiculatus), dinophyte (Peridinium cinctum, Gymnodinium sp., Ceratium furcoides), desmidium algae (Staurodesmus cuspidatus, Cosmarium contractum, C. cucumis) and cyanoprokaryotes (Pseudanabaena galeata, Aphanizomenon flos-aquae, Gloeotrichia echinulata). According to the value of the saprobity index (Pantle – Bucc by number 1.57–2.80), the lake waters correspond to β- and α-mesosaprobic types of waterbodies with III and IV water quality classes (moderately polluted or dirty water).
CONTRIBUTIONS TO THE LICHEN FLORA OF THE TULA REGION
Authors: Muchnik E. E.
Published: April 2024

The article presents the results of field studies in 2021–2022 and revision of the lichenological collection of A.V. Gudovicheva collected in the period from 2000 to 2021. The list of lichen flora of the Tula Region is supplemented with 34 taxa: 28 lichens, 2 allied saprotrophic fungi, and 4 lichenicolous fungi. Cladonia conista, Lecanora sarcopidoides, Lichenodiplis lichenicola, Marchandiomyces corallinus and Pyrenodesmia chalybaea are listed for the first time for the territory of  Central Russia (within the Central Federal District). Bactrospora dryina, Chaenotheca hispidula, Cladonia parasitica and Cresponea chloroconia, as indicators of old-growth intact forest communities, are recommended to be included in the list of rare and vulnerable lichen species. The populations of these species need constant monitoring and control in the Tula Region.
Biology and Distribution of Stellate tadpole-goby Benthophilus stellatus and Don tadpole-goby B. durrelli (Teleostei: Gobiidae)
Authors: Boldyrev V. S. , Basko Yu. V. , Vipkhlo E. V.
Published: April 2024

Size-age and sex population structure have been studied for the aboriginal stellate tadpole-goby Benthophilus stellatus and Don tadpole-goby B. durrelli in the Don River basin. The females of Don tadpole-goby mature at a body length of about 35 mm, stellate tadpole-goby females, at 50 mm. Most breeders of Don tadpole-goby (~74%) are characterized by one-time spawning, stellate tadpole-goby spawns three times. The duration of the breeding season is about 3.5 and 1.5 months, the individual absolute female fecundity is 0.2–0.6 and 1–3 thousand eggs, respectively. All breeders of Don tadpole-goby die after spawning in the second year of life, an insignificant part of stellate tadpole-goby population lives up to three years. The food spectra, size and biotopic variability, the degree of food similarity, and the selectivity of food organisms in both species have been analyzed. The species are characterized by the similarity in feeding and high feeding flexibility. In the Tsimlyansk Reservoir, the main food objects for tadpole-gobies are mosquito larvae and the mollusk Lithoglyphus naticoides, in the lower reaches of the Don River, various crustaceans. We assume three species of tadpole-goby (Don, stellate tadpole-goby and Makhmudbekov tadpole-goby B. mahmudbejovi) inhabit currently in the Volga River reservoirs. Don tadpole-goby has also settled in the lower reaches of the Volga River. Apparently, its range includes the Black Sea, in addition to the native Sea of Azov and newly mastered Volga River basins.
Distribution of the Notched fin eelpout Lycodes pectoralis (Zoarcidae) in the Northeastern Sea of Okhotsk during the Hydrological Summer
Authors: Kurbanov Yu. K.
Published: April 2024

For the first time, the data are presented on the distribution and size composition of the notched fin eelpout Lycodes pectoralis in the northeastern part of the Sea of Okhotsk during the hydrological summer. Its densest aggregations are located on the continental slope of Kamchatka between 52° and 56° N and in the western part of the TINRO depression, in a local area 56°–57° N. The range of the vertical distribution of L. pectoralis covers depths from 199 to 653 m, and the temperature range in which this species occurs is 0–2.3°С. High frequency of occurrence, average density and biomass of the species are typical for depths of 301–400 and 401–500 m at a temperature of the near-bottom water of 1.0–2.0°С. Based on a critical analysis of the literature data and the fact that L. pectoralis is predominantly confined to the habitat in the waters of the unique intermediate water mass of the Sea of Okhotsk, it is suggested that the species is endemic to the Sea of Okhotsk.
Pethia chakpiensis (Cyprinidae), a New Species of Cyprinid Fish from the Chindwin-Irrawaddy Drainage of Manipur, India
Authors: Shangningam B. D. , Kosygin L.
Published: April 2024

Pethia chakpiensis sp. nov. is described from the Chakpi River of the Chindwin-Irrawaddy drainage in Manipur, India. This new species is characterized in having an incomplete lateral line with 4–7 pored scales, 21–24 scales in lateral series; 15 preanal scales; intercalated scale row originates above and after the 5th scale of lateral line scale row; absence of humeral spot; caudal peduncle spot on the 17th and 18th lateral series scales and a longitudinal stripe along the flank.
The European Eel Anguilla anguilla (Anguillidae) Invasion by the Allochthone Nematode Anguillicoloïdes crassus in Southern Mediterranean
Authors: Tahri M. , Bensouilah M.
Published: April 2024

For the first time, the spreading of a fearsome non-native parasite nematode Anguillicoloïdes crassus is studied in European Eel Anguilla anguilla in 4 different coastal ecosystems throughout 12 years. We found that the parasite become more abundant with time in each study site; only 4.8% of eels inhabited brackish water (Mellah Lagoon) are infected while—over the third of fish are infected in the other waterbodies parasite nematode is presented in fish of all ages as well as of both sex; however infected specimens are less common among juveniles and males Based on the evaluation of the swimbladder degenerative index, we found that swimbladder is damaged in more than a half of fish captured in freshwater, however the opposite situation is observed in the brackish water.There is a significant difference in age, length, weight and condition between infected and uninfected fish.
Separated by Space and Time but United by Kinship: Phylogeographical and Phylogenetic History of Two Species of Eleginus (Gadidae) Based on the Polymorphism of Cyt b Mitochondrial DNA Gene
Authors: Chikurova E. A. , Orlov A. M. , Shchepetov D. M. , Orlova S. Yu.
Published: April 2024

Fishes of the genus Eleginus (Gadidae) are typical representatives of the ichthyofauna of the Northern Hemisphere; they play an important trophic role in the marine ecosystems of the Arctic and North Pacific and serve as targets of commercial and artisanal coastal fishing in many areas of the Russian North and Far East, as well as in areas of the coast of Alaska and northern Japan. The level of knowledge about the intraspecific organization of representatives of the genus Eleginus that is necessary for the rational exploitation of their stocks remains insufficient and their interspecific relationships have so far been analyzed using limited materials. This paper presents the first study of the interspecific relationships and intraspecific structure of navaga (E. nawaga) and saffron cod (E. gracilis) using a large-scale material (986 specimens in 29 samples from most of the species ranges) based on analysis of the polymorphism of mtDNA gene Cyt b. It is shown that they are independent, genetically differentiated species and their comparison with representatives of the genus Microgadus indicates that both species of the genus Eleginus might originate from a common ancestor close to M. proximus, while the divergence in the genus Microgadus occurred much earlier. Data on the haplotypic composition of saffron cod samples inhabiting areas from the Peter the Great Bay to Alaska waters and navaga samples inhabiting areas from the White Sea to the Ob Bay of the Kara Sea are given, which makes it possible to consider the phylogeographic history of both species and their intraspecific organization within the studied areas. Three groups can be distinguished for saffron cod: (1) Pacific–Japanese–Sakhalin group, (2) Chukchi–Bering seas group, and (3) intermediate group, which includes samples from the Sea of Okhotsk and waters of the northern Kurils.