bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduction of the Spin–Phonon Coupling of Quadrupole Nuclei in NaF Crystals under Magnetic Saturation
Authors: Mikushev V. M. , Rochev A M. , Charnaya E. V.
Published: April 2024

The rate of nuclear spin-lattice relaxation is determined by the efficiency of interaction between thermal phonons and nuclear spins. The results on reducing the efficiency of spin–phonon coupling by suppressing the contribution from paramagnetic centers to quadrupole nucleus relaxation are presented. The suppression has been performed by stationary magnetic effect at the Larmor frequency. It is shown that, as in the presence of an acoustic field, the rate of spin-lattice relaxation of 23Na nuclei in a sodium fluoride crystal at magnetic saturation of the NMR signal does not change in the region of a negative average spin temperature.In the region of positive spin temperature, the rate of relaxation of 23Na spins significantly decreases and nuclear magnetization recovery with time is described by the sum of two exponentials. The contribution from nuclear spins with a lower efficiency of spin–phonon coupling, corresponding to the exponential with a long relaxation time, increases with increasing saturating field intensity. It is demonstrated that the efficiency of spin–phonon coupling for 19F nuclei without quadrupole moment does not change under the saturation conditions.The results obtained can be used for analyzing the structure of real crystals.
Precision Measurement of the Group Velocity of Ultrasound in Samples with Millimeter Thickness
Authors: Savateeva E. V. , Makalkin D. I. , Karabutov A. A.
Published: April 2024

A methodology is proposed for high-precision local measurement of the group velocity of longitudinal waves in solid samples with millimeter thickness. Achievement of the required accuracy involves laser thermo-optical excitation of submicrosecond ultrasonic video pulses and ultrawideband piezoelectric recording of acoustic signals reflected from the test sample. Plane-parallel samples made of duralumin, quartz, and steel with a thickness of 2–6 mm are studied. To achieve the required accuracy in measuring the group velocityof ultrasound, the signal shape is mathematically processed with compensation for diffraction of the ultrasonic beam as it propagates through the sample. The possibility of ensuring the uncertainty in measuring the group velocity of ultrasound in the 1–15 MHz frequency range at a level of 0.1% in samples with millimeterthickness is demonstrated.
Laser Vibrometry of Shear Waves in a Layer of a Gel-Like Medium
Authors: Asfandiyarov Sh. A. , Agafonov A. A. , Korobov A. I. , Andreev V. G.
Published: April 2024

Abstract—A laser scanning vibrometer was used to measure the amplitudes and phases of the vibrational velocity of shear waves excited by a one-dimensional source in the form of a narrow rectangular bar in a gellike medium. The vibrations of 26 plates reflecting the laser beam and located inside an optically transparentphantom along a segment with a length of 84.5 mm at a distance of 20 mm from the source were measured.The angular distributions of the amplitude and phase of shear waves at discrete frequencies from 59 to 500 Hz were measured in continuous mode. In pulsed mode, the vibrator excited a pulse in the medium with a durationof 1.5 periods of the 300 Hz frequency. The amplitudes and phases of shear waves were calculated by fastFourier transform of the time profile of the vibration velocity of the plates with a duration of 50 ms. The angular amplitude distributions measured in the pulsed and continuous modes are qualitatively the same. At all frequencies, the distributions are symmetrical with respect to the vertical axis. The maximum oscillation amplitude is observed at angles close to ±45°. The velocity of shear waves, calculated from the measured phase distributions, increases from 2 to 2.5 m/s with a change in frequency from 50 to 500 Hz. It is shown that this velocity behavior is well described by a relaxation model of the medium with one relaxation time equal to 0.3 ms. Shear wave attenuation depends on frequency and exceeds 1 cm-1 for waves with frequencies above250 Hz. The maximum attenuation per wavelength is observed near the relaxation frequency of the medium in the 300–400 Hz range. The results can be used to optimize devices for measuring the elasticity of soft tissues.
Assessment of Tracks of Resonance Frequencies of the Vocal Tract
Authors: Leonov A. S. , Sorokin V. N.
Published: April 2024

A new method for estimating formant frequency tracks of the vocal tract for arbitrary speech segments is proposed. The method uses the ratio of two Fourier transforms of a speech signal with special exponential-type windows depending on some parameter. This ratio is used for specific points in time and is considered as a function of frequency and parameter. By analyzing, for several parameter values, the distribution of minimum points (in terms of frequency) for the phase of this ratio and/or a similar distribution of extreme points for its amplitude, it is possible to estimate formant frequencies from the peaks of these distributions. A mathematical study is presented that substantiates this approach. A series of numerical experiments were carried out on the processing of synthetic and real speech signals, which confirmed the performance capabilities of the proposed formant evaluation method. In particular, in experiments with synthesized vowels, it was found that the error in estimating their resonance frequencies is small and stable with respect to additive noise up to a signal-to-noise ratio of 5 dB. For real speech, the method makes it possible to calculate the formant frequency tracks for both sounds with vocal excitation and for voiceless fricatives, aspirated plosives, and whispered speech.
Present State of Zoobenthos in Small Reservoirs of Nothern Slope Baltic-Caspian Watershid of Volgo-Baltic Water Way
Authors: Ivicheva K. N. , Filonenko I. V.
Published: April 2024

In 2010–2013 first investigation of benthic fauna in Novinkinskiy, Belousovskiy and Vytegorskiy water reservoirs were carried out. Totally 103 species of zoobenthos were found. Increase of abundance, species richness and diversity in range profundal–open littoral–thicket littoral was recorded. In profundal of all reservoirs was found complex of species Limnodrilus hoffmeisteri – Procladius. In littoral structure of zoobenthos communities depended from type of substrate and thicket species. Maximum abundance of zoobenthos was recorded in anomaly hot 2010. In comparison with located to the south Volga reservoirs, Novinkinskiy, Belousovskiy Vytegorskiy reservoirs characterized low abundance and species richness.
Ecological Analysis of the Helminth Fauna in the Dice Snake Natrix tessellata (Reptilia, Colubridae) from the Low Volga Region (Russia)
Authors: Kirillov A. A. , Kirillova N. Yu. , Bakiev A. G. , Gorelov R. A.
Published: April 2024

The ecological analysis of the helminth fauna of the Dice snake Natrix tessellata from different habitats of the Astrakhan region in 2004, 2005, 2008 was carried out. The helminth community of the reptile includes 21 species of parasitic worms: 11 trematodes, 1 cestode, 8 nematodes and 1 acanthocephalan. Of these, 11 species are found in all the studied localities and form the basis of N. tessellata helminth fauna. Dominant and subdominant helminth species are found in snakes in all habitats as a result of the implementation of its main trophic relationships. Comparison of the helminth composition from different study sites showed a relatively high degree of similarity. Differences in the helminth fauna of the dice snake from different habitats are insignificant and relate to rare and accidental parasite species. Significant differences in the infection level of snakes with certain species of helminths were revealed. Most of the helminth species that parasitize the water snake have a complex life cycle. The infection of reptiles by them is determined to a large extent by biotic factors: fauna and the number of invertebrates (intermediate hosts of helminths) and vertebrates (paratenic and final hosts) in biocenosis.
Organisation of Fish Assemblage in the Mekong Delta as a Potential Indicator of Salt Water Intrusion
Authors: Malin M. I. , Malina I. P. , Hai Truong Ba , Dinh Cu Nguyen , Man Le Quang , Chi Duong Thi Kim
Published: April 2024

The problem of salt water intrusion into the Mekong Delta is a research topic involving various branches of science. Among the causes of this phenomenon are global sea level rise and regulation of the natural river discharge due to hydropower dam construction. The scale of the delta and its water dynamics complicate instrument-based observations. Meanwhile, communities of living organisms can serve as indicators of environmental heterogeneity. This study aimed to analyze the spatial variability of fish assemblage organisation in the Mekong Delta for use as an indicator of salt water intrusion. The composition of fish assemblages in different parts of the delta were determined by midwater trawl catches during January and April 2021. A total of ~15 thousand individual fish from 74 trawl hauls were captured and analyzed. The null hypothesis was that the fish assemblages in the Mekong Delta are represented by three taxonomic complexes that are localized in the upper course (freshwater), the lower course (brackish) and the middle course (zone of the contact of the fresh and brackish waters) of the delta. The taxonomic composition of the freshwater complex is the most poor and is represented by 9 families. Meanwhile, marginal (the contact zone) and brackish complexes include 26 and 23 families, respectively. Specimens of families Cobitidae, Eleotridae, Plotosidae and Siluridae that are only found in the zone of contact of fresh and brackish waters could be considered as indicator species of its position. The actual boundaries of the brackish and freshwater complexes were determined and the distance from them to the marine delta edge equals 34 and 78 km, respectively. Assessment of the salinity values that correspond to the complex boundaries is a task for future investigation. The position of the boundaries of freshwater and brackish fish taxonomic complexes has a biological basis and could be used as an indicator of salt water intrusion into the Mekong Delta.
Fishes Encountered in the Turkish Thrace River Systems (Northwestern Turkey)
Authors: Özuluğ Müfit , Gaygusuz Özcan , Gaygusuz Çiğdem Gürsoy , Kaya Nilgün , Saç Gülşah
Published: April 2024

In the last 30 years, the natural life in the inland waters of the Turkish Thrace has been threatened by water pollution, deterioration of river continuity, the presence of non-native or invasive fish, and drought. The aim of the present study was to determine the recent status of fish fauna in the river systems lying at the Turkish Thrace, under these threats. The field surveys were conducted in a total of 164 sampling sites in both Marmara and Meriç-Ergene water basins between July and August 2017. A total of 36 freshwater fish species representing 12 families (Acheilognathidae, Atherinidae, Centrarchidae, Cobitidae, Cyprinidae, Esocidae, Gobiidae, Gobionidae, Leuciscidae, Percidae, Poeciliidae, and Salmonidae) were determined. The most widespread species of the region was Cobitis strumicae and it was followed by Rhodeus amarus and Squalius orpheus. This study provides first detailed information on the distribution of the species of Barbus tauricus, Chondrostoma vardarense, Cobitis strumicae, Squalius orpheus, and Vimba melanops.
Features of Zoobenthos of Mesohumus Lakes of the Republic of Karelia in a Natural State
Authors: Savosin E. S. , Savosin D. S.
Published: April 2024

The results of studies of the current state of zoobenthic communities of lakes Sukkozero and Gimolskoye, located in the western part of the Republic of Karelia (Muezersky district), are presented. Under conditions of high color and low mineralization of waters, communities are formed with a predominance of chironomid larvae, caddisflies, mayflies, and oligochaetes. Biomass and abundance indicators in 2017–2018 were within 0.41–0.75 g/m2 and 315–685 ind./m2 in the lake Sukkozero and 0.41–0.93 g/m2 and 220–346 ind./m2 in the lake Gimolskoye. The highest values of abundance and biomass were noted in biotopes of silty soils (overgrown littoral and profundal), the lowest values in the biotope of sandy littoral. According to the level of quantitative development of zoobenthos, Sukkozero belongs to oligotrophic water bodies; Gimolskoye – mesotrophic. The experience of using common biotic indices for assessing the ecological quality of waters (Mayer, oligochaete, saprobity, chironomid) indicates that low mineralization and high humus content can affect their performance and distort the assessment of real organic pollution.
Diatom Assemblages in the Sediment Traps in Lake Onega
Authors: Ludikova A. V.
Published: April 2024

The paper presents the first study of the composition and structure of the diatom assemblages from sediment traps installed in different parts of Lake Onega. 171 species and intraspecific diatom taxa were observed belonging to 59 genera. The predominance of planktonic diatoms is favored by large depths of the lake and a small area of the littoral zone. Aulacoseira islandica and A. subarctica, the most abundant species in spring phytoplankton in Lake Onega dominate in the sediment-traps diatom assemblages. In the sites subject to anthropogenic eutrophication, Aulacoseira ambigua is numerous as well. In a number of sites Lindavia radiosa and Pantocsekiella tripartita are among the subdominating species, while P. schumannii, Stephanodiscus neoastraea and Stephanodiscus sp. are less common. Higher proportions of periphytic Tabellaria fenestrata were recorded in the sites with the largest areas colonized by macrophytes. In all sampling sites, neutrophilous oligo-mesotrophic and oligo-hypereutrophic taxa prevail in the diatom assemblages. The predominance of two or three species in the diatom assemblage results in low values of the floristic diversity index. More diverse diatom assemblages were found in rathers isolated bays. Concentrations of diatom valves and chrysophyte cysts in sediment traps material were also calculated.
Study of the Features of Natural Mortality Iin Muksun and Peladi of the Ob River by Constructing Dependences of the Number of Their Generations
Authors: Matkovskiy A. K.
Published: April 2024

It is shown that it is possible to determine the natural mortality of fish, using the example of muksun (Coregonus muksun) and peled (Coregonus peled) of the Ob River, by constructing dependences of the decrease in the number of generations. It is established that the dynamics of mortality has a U-shaped form. The minimum mortality rates are at the age when sexual maturity reaches more than 70% of individuals. The influence of various natural and anthropogenic factors on natural mortality is shown. It is noted that periodically occurring deficiency of dissolved oxygen has a significant impact on the wintering fish in the southern part of the Gulf of Ob. There was an increase in mortality during fish migrations and this fact can serve as one of the criteria for the periodicity of whitefish spawning. It is established that numerous generations of favorable years of feeding and reproduction are characterized by a higher survival rate of individuals. The presence of genera-tions with different degrees of survival is an important adaptive property of populations.
Tendency of an Increase in the Abundance of Macrozoobenthos Species in the Sevastopol Bay (Black Sea)
Authors: Shalovenkov N. N.
Published: April 2024

In the Sevastopol Bay, degradation of species composition and communities of the zoobenthos began to be shown in the 20's–30's years and has reached maximum demonstration in the 60s–90s years of the last century. Only five species of macrozoobenthos were the most resistant at high anthropogenous loadings and eutrophication in those years. The relative recovery of the species composition and the improvement of benthic biological parameters are observed in the bay since the beginning of the 21st century. The zoobenthos was replenished by 39 new species which here were not marked earlier. Mollusca, Crustacea and Polychaete, among taxonomic groups of zoobenthos, had the greatest quantity of new species. Registration of the zoobenthic animals even in areas, which were earlier as “dead zone”, indicates an improvement of habitat in the Bay. The reduction of the eutrophic level, the oxygen regime improvement and the area expansion with oxidizing conditions in bottom sediment were the major factors in improving benthic habitats in the Sevastopol Bay. These ecological changes coincided with increase of water temperature in the summer period. The positive tendencies for a zoobenthos are typical for the Romania, Bulgarian coasts in the last decade.
The Benthic Macroinvertebrates of the Kızılırmak River (Nevşehir, Turkey) and Their Relation with Environmental Variables
Authors: Aras Seval , Findik Ozlem
Published: April 2024

Turkey has many ecological characteristics due to its geographical location, allowing it to have a rich biodiversity in freshwater ecosystems. This study was carried out on the Kızılırmak river, the longest river (1.355 km) in the country; it originates and empties into the sea within its borders. The Kızılırmak river serves various agricultural, industrial, drinking water-related, and recreational purposes and greatly contributes to the region’s economy. This study aimed to determine the distribution of the river’s macroinvertebrate fauna and evaluate the impact of environmental variables on species distribution. In addition, using species-based biodiversity indices such as the Biological Monitoring Working Party (BMWP), Average Score per Taxon (ASPT), the Shannon–Wiener index, and evenness analysis, spatial and temporal similarities and differences were determined. According to the results, the ten taxonomic groups in the Kızılırmak river belong to the following categories: Gastropoda (81.5%), Gammaridae (9.8%), Oligochaeta (6.2%) Chironomidae (2.1%), Hirudinea (0.3%), and various others (0.1%). The Shannon–Wiener and evenness indexes were 0.29–1.9 and 0.46–0.14, respectively. TR-BMWP scores are in the poor to very poor water quality classes, and the ASPT ranges from moderate to poor water quality. Correlation analysis between species and physicochemical parameters indicated that the benthic macroinvertebrate fauna diversity of the river is affected by natural and anthropogenic factors.
Mollusc Anadara kagoshimensis, Allien Species, in Structures of the Benthic Communities on the Crimea Shelf
Authors: Shalovenkov N. N.
Published: April 2024

The frequency of occurrence of the mollusc-invader, Anadara kagoshimensis (Tokunaga, 1906), increased from 5 to 17–23% in zoobenthos of the South Coast of the Crimea Shelf for the last fifteen years. At the same time, the rate of the non-native mollusc was not significant and fluctuated: 0.73–23.29% from the biomass and 0.19–2.20% from abundance of the macrozoobenthos in the benthic communities. The mollusc A. kagoshimensis has been registered in the three communities: Chamelea gallina, Gouldia minima–Pitar rudis and Gouldia minima. The mollusc Anadara has not formed an independent community here. Influence of this alien species on bottom communities of the Crimean Coast was not such considerable as on bottom communities in northwest or in east parts of Black Sea Shelf. The structure of benthic communities had no significant changes on the shelf of the Southern Coast of the Crimea, compared with 70–80 of the last century. The first registration and the settlement of the mollusc-invader on the Crimea Shelf coincides with salinity decrease and temperature rise of coastal waters which are observed during last decade.
Regional Differences in the Infection of the European Anchoy Engraulis encrasicolus with the Nematode Hysterothylacium aduncum in the Winter Period of the Crimea and the Caucasus Coasts
Authors: Zavyalov A. V. , Samotoi Ju. V. , Sibirtsova E. N.
Published: April 2024

The main indicators of infestation of European anchovy Engraulis encrasicolus (L.) with larvae of the nematode Hysterothylacium aduncum (Rudolphi, 1802) in winter were studied in two areas of the Black Sea: off the coast of Crimea and the Caucasus. Regional differences in the indicators of invasion intensity and abundance index in two-year-old and three-year-olds were revealed. When analyzing the values of the extensiveness of invasion, no significant differences were found. Three main factors that determine regional differences in anchovy infestation in the studied areas are analyzed.
Salinity as a Factor Limiting the Crustacean Potential Taxonomic Richness in the World’s Hypersaline Water Ecosystems: a Review
Authors: Anufriieva E. V. , Shadrin N. V.
Published: April 2024

Crustaceans are one of the biosphere’s most diverse and successful groups, also inhabiting various extreme habitats. Summing up our data and 203 literary sources, we analyzed how the degree of environmental extremeness can limit the potential taxonomic richness of crustaceans using the example of hypersaline waters. An analysis showed that, with an increase in salinity, the number of classes and orders of the Crustacea subtype decreased linearly, while the number of genera and species decreased exponentially. It has been established that with an increase in environmental salinity, the contribution of Arthropoda species to the total species richness of animals in hypersaline waters increases from 49 to 100%, the gift of Crustacea species to the total species richness of Arthropoda increases from 66 to 78%, and the contribution of Branchiopoda to the species richness of Crustacea from 19 to 71%. In the Crimean hypersaline water bodies, in the range from 35 to 120 g/L, salinity is not the main factor determining the species richness and composition of the fauna, the combination of all other factors, primarily biotic ones, plays a more critical role. Only at higher values, salinity itself begins to play the role of a hard-environmental filter. Salinity growing above 35 g/L reduces the comfort of the environment for animals and filters out the pool of species that can exist in the ecosystem. In particular water bodies, the realization of this possibility depends not only on salinity but also on the existing biotic relationships and the entire set of abiotic factors.
Unique Haplotypes of Artemia salina (Crustacea, Branchiopoda, Anostraca) in Hypersaline Lake Sasyk-Sivash (Crimea)
Authors: Lantushenko A. O. , Meger Ya. V. , Gadzhi A. V. , Anufriieva E. V. , Shadrin N. V.
Published: April 2024

The genetic structure of the population of the Artemia salina (L., 1758) species from the hypersaline lake Sasyk-Sivash was studied on the basis of a fragment of the gene of the first subunit of cytochrome oxidase c (COI) of mitochondrial DNA. The phylogeny reconstruction was performed using all available nucleotide sequences of this gene for the salina species in the GenBank (NCBI) international database. Genealogical connections between COI haplotypes have been established and phylogeographic patterns have been revealed. Common haplotypes have been noted in Western Mediterranean populations, which may be a consequence of their location in a single migration corridor of birds, which, as is known, contribute to the passive spread of dormant stages of artemia. Geographically isolated groups of populations from Libya, Tunisia, Egypt, Cyprus and Crimea are characterized by unique haplotypes that are not currently found in other Mediterranean populations. It is suggested that unique haplotypes may be endemic to geographically remote regions.
The First Record of Acanthocyclops trajani (Copepoda, Cyclopidae) in the Vistula Lagoon of the Baltic Sea
Authors: Semenova A. S. , Mirabdullaev I. M. , Sheveleva N. G. , Podshivalina V. N.
Published: April 2024

In 2021 Acanthocyclops trajani Mirabdullayev et Defaye, 2002, was first record in the Vistula Lagoon of the Baltic Sea. This species quickly spread throughout the water area of the Lagoon. In summer, A. trajani reached its maximum development (up to 92 thousand ind./m3, 2.4 g/m3), was a dominant and forming a particularly high proportion of zooplankton in the most polluted, desalinated and eutrophicated eastern part of the Vistula Lagoon. As a result of predatory feeding, A. trajani exerted significant pressure on the planktonic communities of the Lagoon; its diet in August exceeded the production of non-predatory zooplankton. The pressure on zooplankton increased even more due to the mass development of Cercopagis pengoi (Ostroumov, 1891), with which the new species entered into competitive relationships. The main reasons for the successful naturalization of A. trajani in the Vistula Lagoon, apparently, include some features of its biology, the structure of the plankton community with the presence of unoccupied trophic niches, the continued eutrophication this waterbody, decreasing the pressure of the invasive mollusk Rangia cuneata (G.B. Sowerby, 1831), as well as local climate warming, noted in recent decades.
Comparison of Olfactory Sensilla Structure in Littoral and Deep-Water Amphipods from the Baikal Region
Authors: Shirokova Y. A. , Saranchina A. E. , Shatilina Zh. M. , Kashchuk N. D. , Timofeyev M. A.
Published: April 2024

The structure of olfactory sensilla was compared in amphipods from the Baikal region, namely in nine Baikal species (Ommatogammarus carneolus melanophthalmus Bazikalova, 1945, O. flavus (Dybowsky, 1874), O. albinus (Dybowsky, 1874), Eulimnogammarus verrucosus (Gerstfeldt, 1858), E. vittatus (Dybowsky, 1874), E. cyaneus (Dybowsky, 1874), Acanthogammarus godlewskii (Dybowsky, 1874), Pallasea cancelloides (Gerstfeldt, 1858) and Gmelinoides fasciatus (Stebbing, 1899)) and a Holarctic species Gammarus lacustris Sars, 1863. The results of the study demonstrate the comparison of aesthetasc lengths and numbers, as well as SEM images of the aesthetascs for Baikal amphipods for the first time. Our results confirm and complement the previously obtained data on the number of aesthetascs per segment for three deep-water Baikal amphipod species of the genus Ommatogammarus. Within the studied deep-water amphipods with different habitat depth ranges, Ommatogammarus albinus (Dybowsky, 1874), inhabiting maximum habitat depth, had the highest number of aesthetascs. The size and number of aesthetascs did not differ in males and females of the littoral Eulimnogammarus verrucosus (Gerstfeldt, 1858) and deep-water species. The littoral amphipods were shown to have equipped with more mechanoreceptors antennae I than deep-water amphipods.
The First Record of the Siberian Species Leptodiaptomus cf. angustilobus (Copepoda: Calanoida) in Europe
Authors: Shurganova G. V. , Zhikharev V. S. , Fefilova E. B. , Tereshina M. A. , Dubovskaya О. P. , Gavrilko D. E.
Published: April 2024

The Siberian species, identified as Leptodiaptomus cf. angustilobus (Sars G.O., 1898), was found for the first time in Europe (Russia, Nizhny Novgorod Region, mouth region of the Kerzhenets River (Middle Volga), 56°6′5″ N, 44°57′28″ E). A brief morphology description with illustrations of the species is presented. Differences between females from the Nizhny Novgorod Region and Siberia in the morphometry of abdominal somites, antennules, and the fifth legs are shown. We also obtained data on abundance of L. cf. angustilobus in the plankton community of the mouth area of the Kerzhenets River and described habitat conditions of new for this region species of Diaptomidae.
Changes in Phyto- and Zooplankton under the Climatic Shifts and Anthropogenic Load (Lake Baikal, Russia)
Authors: Bondarenko N. A. , Tomberg I. V. , Pen’kova O. G. , Sheveleva N. G.
Published: April 2024

The hydro-chemical data collected today and structural and quantitative parameters of phyto- and zooplankton from Maloe More Strait, Lake Baikal, were analysed. Comparison of current and earlier observations revealed recent alterations in phyto- and zooplankton functions analogous to other areas of Lake Baikal. Major reconstructions in phytoplankton were registered in spring: violation in cycles of annual growth maxima of large-cell Baikalian diatoms and changes in dominant species. Dramatic abundance of rotifers caused the increase by an order of magnitude in pelagic zooplankton numbers in 2019–2020. In 2021, all of these groups were suppressed under intensive diatom vegetation. In the Mukhor bay, such changes were related to a sharp increase of rotifer numbers until 2021. In 2021, we observed decline in plankton abundance, meanwhile the relative proportion of taxonomic groups did not change with dominance of rotifers.
Effect of a Gradual Salinity Increase on Water Quality, Survival and Growth Performance of Hybrid Red Tilapia (Oreochromis mossambicus ×O. niloticus)1
Authors: Chabet dis C. , Amira Didani , Rachida Itchir , Wissam Chaichi , Bouchra Abidi , Besma Larbi Ben Houra , Amina Seffah
Published: April 2024

We studied the effect of increasing salinity with respect to growth performance and water quality of Hybrid Red Tilapia (Oreochromis mossambicus × O. niloticus) (1.29 ± 0.48 g and 4.05 ± 0.48 cm) for 77 days, and we compared the obtained results to freshwater rearing. The results indicate no significant difference in all physico-chemical parameters between both variants, which are within the accepted range for fish growth. Better growth performance regarding weight was observed in freshwater rearing. However, in terms of length, the increasing salinity rearing showed the best growth performance. The survival rate decreased with a salinity increase, unlike freshwater rearing which showed 100%. Hybrid Red Tilapia raised in freshwater revealed isometric growth. However, Hybrid Red Tilapia reared in increasing salinity reported negative allometric growth. A strong positive correlation was observed between salinity and total length and weight, and between total length and total weight, while survival was strongly negatively correlated with salinity and total weight. Positive loadings of salinity, N\({\text{H}}_{4}^{ + }\), total length, and total weight were observed relatively to the factor 1, whereas N\({\text{O}}_{2}^{ - }\) and survival show negative loadings. For the factor 2, the chemical variables (N\({\text{O}}_{2}^{ - }\), P\({\text{O}}_{4}^{{3 - }}\) and N\({\text{H}}_{4}^{ + }\)) were the important variables. Our experiment suggests that Hybrid Red Tilapia can be reared in biotopes that are subject to climate change or that experience a hot and dry climate.
Abundance, Distribution and Mortality of Hydrobionts in the Section of the Gorky Reservoir Affected by Heated Waters of the Kostroma Hydroelectric Power Plant
Authors: Gerasimov Yu. V. , Bolotov S. E. , Tsvetkov A. I. , Borisenko E. S.
Published: April 2024

The study was conducted in the river section of the Gorky reservoir in the zone affected by the heated water discharge from the Kostroma hydroelectric power plant during the growing season (May–November) 2021. The reduced species richness was observed in the sites of the maximum water heating, which, however, quickly returned to the initial values in the downstream section of the river. The lethal effect of warm waters on zooplankton is mainly manifested in the summer, when the natural warming of the river waters is influenced by the heated water discharge from the Kostroma hydroelectric power plant. In autumn, the warming effect of heated waters, on the contrary, promotes better survival of organisms. Fish reach a high abundance in the study area by the end of summer, when the grown juvenile sleave shallow waters. In the autumn period, the fish redistribution and a significant increase in the abundance occur in the area of heated waters compared to the back ground sites. The results obtained indicate the absence of an environmentally significant lethal effect. Local plankton losses are quickly compensated due to high reproduction rates and short-cycle development of invertebrates. The lethal effect of exposure to high temperatures on fish was not found.
Salinity Tolerance, Seasonal and Multiyear Dynamics of Biting Midges (Diptera, Ceratopogonidae) in Macrozoobenthos Communities of Saline Rivers (the Lake Elton Basin, Russia)
Authors: Golovatyuk L. V.
Published: April 2024

The results of long-term studies of biting midges (Diptera, Ceratopogonidae) in macrozoobenthos communities of five saline rivers of the hyperhaline Lake Elton basin are presented. The fauna of Ceratopogonidae includes 5 halophilic and euryhaline species, among which representatives of the tribe Palpomyiinae predominate. Taxonomic composition of the family differs in rivers with different levels of salinity. Species Sphaeromias miricornis and Culicoides riethi are widely distributed in mesohaline the Khara, the Lantsug and the Bolshaya Samoroda rivers, and P. schmidti widely distributed in polyhaline the Chernavka and the Solyanka rivers. Two generations of S. miricornis and three generations of P. schmidti were recorded. Departure of the first generation of P. schmidti occurs in mid-May, S. miricornis in late May–early June. There is an increase in mean annual abundance and biomass of biting midges in polyhaline rivers compared to mesohaline rivers.
Effect of Algicide Based on Metabolites, Allelochemicals of Aquatic Plants on Seed Germination and the Development of Seedlings of Three Species of Helophytes
Authors: Lapirov A. G. , Belyakov E. A. , Lebedeva O. A. , Kurashov E. A. , Krylova J. V.
Published: April 2024

For the first time, the effect of a patented alcoholic solution of algicide on seed germination and the development of seedlings of three species of helophytes Sparganium emersum, S. glomeratum and Schoenoplectus lacustris was studied based on gallic, tetradecanoic, heptane and octane organic acids. Significant differences were found in the effect of different algicide concentrations (0.1, 1.0 and 10.0 mg/L) on seed germination and the initial stages of seedling development of three species of helophytes. We observed the stimulation of germination of Sparganium emersum seeds at a concentration of 10.0 mg/L and inhibition of this process in S. glomeratum at concentrations of 1.0 and 0.1 mg/L. No significant effect of algicide on the germination of Schoenoplectus lacustris seeds was found. According to the degree of increase in the resistance of morphological parameters of plants to the effect of different algicide concentrations, seedlings of three species of helophytes are arranged in the following series: Schoenoplectus lacustris Sparganium glomeratum S. emersum.
Genetic Variation among Three Species of Genus Erythroculter
Authors: Qiao Deliang , Chen Yunbo , Deng Hui , He Xiaomei , Xia Lunbin
Published: April 2024

The genus Erythroculter (Cypriniformes, Cyprinidae, Abramidinae) is one of the most commercially important freshwater fish species inhabiting China. However, very limited information is available regarding genetic variation among Erythroculter species, therefore hindering their effective management. In this regard, microsatellite markers and sequences of mitochondrial COII and D-loop were analyzed to investigate the genetic variation among three species of genus Erythroculter. Results demonstrated that 11 microsatellite loci were amplified effectually, and the size of allele was 110–350, 94–338 and 86–384 bps in E. ilishaeformis, E. dabryi and E. mongolicus respectively. Average number of allele was 5.82, 5.73 and 6.45 per locus for E. ilishaeformis, E. dabryi and E. mongolicus respectively. Fragments of COII and D-loop was 675 and 929 bps respectively. On the basis of Shannon’s information index, heterozygosity, polymorphic information content and nucleotide diversity index (P), the microsatellite and nucleotide diversity of E. ilishaeformis was most abundant, and that of E. mongolicus was least abundant. Based on the haplotype distribution of D-loop or the allele size in microsatellite loci of EI19 or HWB05, it could be distinguished perfectly among E. ilishaeformis, E. dabryi and E. mongolicus. Some historical and environmental elements might result in the high genetic divergence and promote the speciation of E. ilishaeformis, E. dabryi and E. mongolicus. These results would be of avail in the conservation and sustainable utilization of these three species.
Stable Differences in Growth Rates of Juvenile Triploid Oysters Crassostrea gigas
Authors: Vialova O. Yu.
Published: April 2024

The three groups of mollusks of the triploid Pacific oyster Crassostrea gigas from the Liman Donuzlav (Black Sea), differing in morphometric characteristics: fast growing (FG) – shell height (H) 40 mm, medium growing (MG) – 15 mm H 40 mm and slow growing (SG) – H 15 mm, were studied. The stable differences in the growth rates of juveniles of the same age were revealed. Mollusks of the FG group were the leaders in terms of weight gain and linear size throughout the study. The average daily increase in shell height in the studied mollusks ranged from 0.1 to 0.35 mm/day, with maximum values in June and September. Weight gain occurred with different intensity, on average in SG – 0.051 g/day, in MG – 0.168 g/day, in FG – 0.287 g/day. The peaks of this indicator were in August and September, reaching 0.12, 0.26 and 0.43 g/day, respectively. A negative allometry of the shell in height was obtained in slow–growing polyploid oysters (b = 2.17), in the other two other groups – a clear positive (for MG b = 3.23, for FG b = 3.80), i.e., the increase in mass was faster than linear growth in juveniles of the species. Polyploidy (triploidy) is suggested as the reason for the differences in the growth rates of the same-aged mollusks. The allometry indicator b can be used to identify growth features in the early stages of oyster development.
Influence of the structure of the coat protein N-terminal segment in potato virus X and alternanthera mosaic virus on the structure and physico-chemical properties of virions
Authors: Ksenofontov A. L , Petoukhov M. V , Matveev V. V , Fedorova N. V , Semenyuk P. I , Arutyunyan A. M , Manukhova T. I , Evtushenko E. A , Nikitin N. A
Published: April 2024

The amino acid sequences of coat proteins (CPs) of potexviruses such as potato virus X (PVX) and alternanthera mosaic virus (AltMV) share about 40% sequence identity. However, the N-terminal CP domains of these virions differ both in length (the N-terminal CP domain of PVX is longer by 28 residues, ∆N = 28), and in amino acid sequence. In this work, we determined the effect of the N-terminal CP domain on the structure and physicochemical properties of the entire PVX and AltMV virions. It was shown that the melting point of PVX samples is 10-12°C higher than that of AltMV preparations; the circular dichroism spectra of these viruses also differ significantly. Spatial alignment of the existing high-resolution potexvirus CP structures showed that the RMSD value between Cα-atoms was the largest for the N-terminal domains of the two compared models. From computer simulations the ∆N-terminal CP domain of PVX is completely disordered. According to synchrotron small-angle X-ray scattering (SAXS) data, the structure of CP of PVX and AltMV virions differs, in particular, CP PVX has a larger size of crystallinity regions and, therefore, is more ordered. Using SAXS, virion diameters and helix parameters in solution are calculated. The influence of the conformation and localization of the N-terminal domain of PVX CP relative to the surface of the virion on its structure was revealed. Presumably, the increased thermal stability of PVX virions compared to AltMV is provided by the elongated N-terminal domains (ΔN = 28), which ensures additional contact between the adjacent CP subunits in the PVX virion.
Melatonin can enhance the effect of drugs used in the treatment of leukemia
Authors: Lomovskiy A. I , Baburina Yu. L , Fadeev R. S , Lomovskaya Y. V , Kobyakova M. I , Krestinin R. R , Sotnikova L. D , Krestinina O. V
Published: April 2024

Melatonin (N-acetyl-5-methoxytryptamine, MEL), secreted by the pineal gland, plays an important role in the regulation of the different functions in human. However, there are the facts that MEL has an antitumor effect in various types of cancer. We have studied the combined effect of MEL and targeted drugs such as cytarabine (CYT) and navitoclax (ABT-737) on the development of acute myeloid leukemia in the MV4-11 cell model. The combined action of MEL with CYT or ABT-737 contributed to a decrease in the proliferative activity of leukemia cells, a drop in the membrane potential of mitochondria, and an increase in the production of reactive oxygen species and cytosolic Ca2+. We have shown that MEL, together with CYT or ABT-737, increases expression of homologous C/EBP protein and autophagy marker LC3A/B and decreases protein disulfide isomerase and immunoglobulin-binding protein levels, and consequently modulate endoplasmic stress. reticulum and initiate autophagy. The obtained data support the earlier suggestion that MEL may have potential benefits in cancer treatment and may be considered as an additive to drugs used in therapy.
Opportunities of complex analysis in single-cell RNA sequencing
Authors: Khozyainova A. A , Valyaeva A. A , Arbatsky M. S , Isaev S. V , Iamshchikov P. S , Volchkov E. V , Sabirov M. S , Zainullina V. R , Chechekhin V. I
Published: April 2024

Single-cell RNA sequencing (scRNA-seq) is a revolutionary tool for studying the physiology of normal and pathologically altered tissues. This approach provides information about the molecular features (gene expression, mutations, chromatin accessibility, etc.) of cells, opens up the possibility to analyze cell differentiation trajectories/phylogeny and cell-cell interactions and allows discovering new cell types and previously unexplored processes. From a clinical point of view, scRNA-seq allows a deeper and more detailed analysis of the molecular mechanisms of various diseases and serves as the basis for the development of new preventive, diagnostic and therapeutic solutions. This review describes the different approaches to analysis of scRNA-seq data, reviews the strengths and weaknesses of bioinformatic tools, provides recommendations and examples of their successful use and suggests potential directions for improvement. It also emphasizes the need to create new, including multi-omics, protocols for the preparation of DNA/RNA libraries of single cells in order to obtain a more complete and systematic understanding of each cell.
pH-dependent redox properties of epigallocatechin gallate (EGCG) and its effect on respiration, photosynthesis and cell death in pea
Authors: Kiselevsky D. B , Samuilova O. V , Samuilov V. D
Published: April 2024

The redox properties of the green tea component epigallocatechin gallate (EGCG) in vitro were studied and its effect on plant (pea) cells was tested. EGCG exhibited both pro- and antioxidant properties. In solutions, EGCG was oxidized by oxygen at physiological (slightly alkaline) pH values. Lowering the pH slowed down this process. Oxidation of EGCG was accompanied by the formation of O2-• and H2O2. In addition, EGCG functioned as an electron donor for peroxidase and, in combination with it, utilized H2O2. Exposure of EGCG to pea cells (leaf cuts or epidermis) suppressed respiration, reduced the transmembrane electric potential difference (Δψ) in mitochondria, and inhibited electron transfer in the photosynthetic electron transfer chain. Among the sites of the photosynthetic redox chain, Photosystem II was the least sensitive to the action of EGCG. EGCG reduced the rate of formation of reactive oxygen species in the epidermis, which was induced by NADH treatment and was registered using 2′,7′-dichlorofluorescine diacetate. In vivo, EGCG at concentrations from 10 µM to 1 mM suppressed KCN-induced death of guard cells in the epidermis, which was determined from the destruction of cell nuclei. EGCG at a concentration of 10 mM disrupted the barrier function of the guard cell plasma membrane, increasing its permeability to propidium iodide.
Curative potential of high-value phytochemicals on COVID-19 infection
Authors: Sruthi D. , Dhanalakshmi M. , Rao H. Ch.Y , Deepanraj Sh. P , Jayabaskaran C.
Published: April 2024

Medicinal plants and their therapeutically promising chemical compounds belonging to the valued category of ‘traditional medicine’ are potential remedies for various health problems. Due to their complex structure and enormous health benefits, the high-value plant-derived metabolites collectively termed as ‘phytochemicals’ have emerged as a crucial source for novel drug discovery and development. Indeed, several medicinal plants from diverse habitats are still in the ‘underexplored’ category in terms of their bioactive principles and therapeutic potential. COVID-19, infection caused by the SARS-CoV-2, first reported in November 2019, resulted in the alarming number of deaths (6.61 million), was further declared ‘pandemic’, and spread of the disease has continued till today. Even though the well-established scientific world has successfully implemented vaccines against COVID-19 within the short period of time, the focus on alternative remedies for long-term symptom management and immunity boosting have been increased. At this point, interventions based on traditional medicine, which include medicinal plants, their bioactive metabolites, extracts and formulations, attracted a lot of attention as alternative solutions for COVID-19 management. Here, we reviewed the recent research findings related to the effectiveness of phytochemicals in treatment or prevention of COVID-19. Furthermore, the literature regarding the mechanisms behind the preventive or therapeutic effects of these natural phytochemicals were also discussed. In conclusion, we suggest that the active plant-derived components could be used alone or in combination as an alternative solution for the management of SARS-CoV-2 infection. Moreover, the structure of these natural productomes may lead to the emergence of new prophylactic strategies for SARS-CoV-2-caused infection.
Interaction between adipocytes and B lymphocytes in human metabolic diseases
Authors: Stasevich E. M , Zheremyan E. A , Kuprash D. V , Schwartz A. M
Published: April 2024

Diseases associated with disorders of carbohydrate and fat metabolism are widespread in the modern world. An essential factor in the pathogenesis of such diseases is the interaction between the cells of adipose tissue, adipocytes, and immune system cells. A long-term increase in glucose and fatty acids leads to adipocyte hypertrophy and increased expression of proinflammatory cytokines and adipokines by these cells. As a result, immune cells acquire a pro-inflammatory phenotype, and new leukocytes are recruited. Inflammation of adipose tissue leads to insulin resistance and stimulates the formation of atherosclerotic plaques and the development of autoimmune processes. New studies show that different groups of B lymphocytes play an essential role in the regulation of inflammation in adipose tissue. A decrease in B2 type lymphocytes suppresses the development of a number of metabolic diseases, whereas decreased numbers of regulatory B lymphocytes and B1 lymphocytes are associated with an increased pathology. Recent studies showed that adipocytes influence B lymphocyte activity both directly and by altering the activity of other immune cells. These findings provide a better understanding of the molecular mechanisms of human pathologies associated with impaired carbohydrate and lipid metabolism, such as type 2 diabetes mellitus.