The impact of plastic particles on living organisms must be studied to develop monitoring and other environmental protection activities. Baikal endemic gastropods, Benedictia baicalensis, were cultivated for 9 months in the presence of fluorescently labeled polystyrene (PS) and polyvinyl chloride (PVC) nanoparticles with a diameter of 80 to 150 nm at concentrations of 0.01, 0.1, and 1 mg/L. Light, laser confocal microscopy, and scanning electron microscopy methods were used to characterize the impact of plastics. Comparison of degenerative changes in the digestive diverticula caused by exposure to different concentrations of both types of nanoplastics did not reveal significant differences. On the third day of mollusk cultivation in the presence of nanoplastics in the digestive gland, secretion and vacuolation of digestive cells increased, resulting in the disaggregation of the native structure of the digestive diverticula. The formation of large swelling sites is a common morphological feature of pathological changes in the digestive gland with chronic exposure to PS and PVC. During mollusk cultivation in the presence of PS at a concentration of 1 mg/L, large swelling sites were observed by the fifth month of the experiment, followed by the death of the animals. Similar degenerative changes occurred in the digestive gland of mollusks 9 months after nanoplastic exposure at concentrations of 0.01 and 0.1 mg/L. This indicates a cumulative effect of the toxic action of these xenobiotics, which increases the hazard of their long-term exposure and can disrupt natural processes of digestion and detoxification of foreign chemical substances.

Effective methods for indicating the state of lake ecosystems are important for preserving them. The focus of this study is the F-actin 3D-structure analysis of the normal fish epidermis and the evaluation of this methodological approach for the study of adaptive epidermal rearrangements in the bioindication technologies. This observational study was conducted on Leocottus kesslerii (Kessler’s sculpin) from Lake Baikal. Laser confocal microscopy was used to analyze the three-dimensional structure of the F-actin. It was shown that the microfilament system in epitheliocytes forms a spatial network with a reinforced framework in the external cell layer. The apical side of outer epidermal cells contains numerous actin patches that can be essential for interactions with the environment. We analyzed natural micro disruptions of the epidermis in L. kesslerii at the stage of reparation. In the main area of the damaged tissue, the actin cytoskeleton of keratocytes was dissociated. In these regions, a few cells with F-actin locomotory structures were detected: torpedo-shaped cells, cells with pseudopodia, and de novo formed clusters of epidermal cells. Also, we detected the large extracellular F-actin deposits colocalized with DNA in areas of necrotic cell debris location. Potentially, these extracellular molecules can enforce immunity or overstimulate inflammation. All of these data show the high ability of actin cytoskeleton to adaptive reconstructions. Overall, the obtained data on F-actin rearrangements in damaged fish epidermis has the potential for development of a methodological approach for biomonitoring of lakes and other water bodies ecosystems.

Magnetic ferrocarbon materials based on a nanocomposite of natural polysaccharide arabinogalactan with magnetite nanoparticles were obtained by heat treatment. In the process of thermal destruction with heating to 410–430 °C in an oxidizing atmosphere, nanosized carbon-shielded magnetite particles are formed. The obtained ferrocarbon powders are finely dispersed showing an average predominant nanoparticle diameter of 5–6 nm. The study of the analysis of ferrocarbon material formation was conducted using electron paramagnetic resonance and synchronous thermal analysis methods. Morphometric parameters were studied by transmission and scanning electron microscopy, as well as laser confocal microscopy. Structural changes were analyzed by X-ray diffraction analysis, magnetic resonance and infrared spectroscopy, which confirmed the preservation of the magnetic phase of magnetite during the carbonization of the organic matrix.

Oral mucositis is a complex inflammatory and ulcerative condition frequently associated with a heightened risk of infections, malnutrition and diminished quality of life in both humans and animals. Despite the availability of various preventive and therapeutic interventions, their overall efficacy remains unclear. Considering that vitamin D exhibits pronounced anti-inflammatory properties by modulating autophagic pathways via activation of the vitamin D receptor (VDR), the present study aims to determine whether supplementation with vitamin D after the mucogingival replacement surgery (MGRS) would effectively enhance autophagy, and therefore, protect the integrity of mucosal lining in cases of severe oral mucositis. Adult domestic cats suffered from feline chronic gingivostomatitis and undergoing MGRS were used in this study. After MGRS, experimental cats were orally administered either fat-soluble or water-soluble vitamin D at a dose of 200 ng/kg twice daily for 6 weeks. Quantitative analysis revealed that in cats with oral mucositis and received MGRS, post-operative supplementation of both types of vitamin D greatly improved the quality of life and increased the anti-inflammatory reactivity. Moreover, both types of vitamin D considerably enhanced the expression of VDR and light chain 3B (LC3B, a biochemical marker for autophagy) within the affected tissues, with the most notable change observed in cats that received fat-soluble vitamin D. Based on these findings, incorporating vitamin D into the post-operative care regimens may enhance the therapeutic efficacy of surgical interventions targeting severe mucosal injury. This strategy may also hold a novel promise for improving the overall management of oral mucositis and associated complications.

The morphological peculiarities of receptor neurons and support cells in the olfactory epithelium of male yellowfin sculpin (Cottocomephorus grewingkii; Dybowski, 1874) were studied during the pre-spawning, spawning (when males do not feed and have a higher sensitivity to female pheromones), and guarding (the fertilized eggs) periods. This study was performed using electron transmission and laser confocal microscopy. Structural changes in the fish olfactory epithelium are associated with the shift in olfactory signals from alimentary to pheromonal. These results expand our knowledge of the odorant-dependent plasticity of the periphery of the fish olfactory system.

Purpose: To evaluate ultrastructural characteristics of lenticule surface extracted during correction of residual myopia in patients after small-incision lenticule extraction (SMILE). Methods and material: This study had a prospective, consecutive, comparative design. Sixteen patients (16 eyes) underwent additional intervention for residual myopia correction after SMILE. 16 specimens of removed lenticules underwent morphological examination. Markers and reagents were used to determine actin microfilaments, neutral fats and cell nuclei. The tissue was analyzed in layers in 2D slices form, volumetric Z-stacks, or selected areas were formed in orthogonal projections. The surface of the extracted lenticule was analyzed using scanning electron microscopy. Patients’ refractive outcomes were measured postoperatively (1 day; 1 and 3 months). Results: Postoperatively uncorrected distance visual acuity (20/20 or better) was in 100% cases 3 months after surgery. Ultrastructural studies have shown the difference in surfaces of the newly formed lenticule. Structural changes of the posterior lenticule surface were characterized by ruptures of collagen fibers on its surface, degenerative changes in keratocytes with signs of colliquation necrosis, cell apoptosis and F-actin in cell cytoplasm. Conclusion: Collagen fibers are immersed in the stroma on the anterior surface of the lenticule. There is no complete structure restoration of collagen fibers explaining the lack of tight adhesion of anterior and posterior surfaces of the intrastromal space even in the long-term postoperative period. There are no degenerative changes of keratocytes on the anterior lenticule surface, that is, their changes in SMILE are reversible in most cases.

A new method is proposed for obtaining quantum dots based on cadmium chalcogenides CdE (E = S, Se, Te) by chemisorption of polyalkylene chalcogenides on the surface of nanoparticles with the formation of the dendrimeric architecture of nanocomposites. The obtained materials are of interest in various applications in engineering and biomedicine. Nanosystems are long-term aggregatively stable, and the sizes of the nanoparticles were estimated from X-ray diffraction data using the Scherrer formula and transmission electron microscopy. Other structural characteristics and paramagnetic properties of nanocomposites were studied by modern physicochemical methods (Fourier transform infrared spectroscopy, scanning electron microscopy, photoluminescence measurements, etc.). In the electron paramagnetic resonance spectra of nanocomposites the main signal due to conduction electrons was recorded, which demonstrates the quantum size effect of the resulting quantum dots.

The effect is studied of water-suspended soot microparticles on the actin cytoskeleton, apoptosis, and proliferation in the gill epithelium of pearl gourami. To this end, the fish are kept in aquariums with 0.005 g/L of soot for 5 and 14 days. Laser confocal microscopy is used to find that at the analyzed times of exposure to the pollutant zones appear in the gill epithelium, where the actin framework of adhesion belts dissociates and F-actin either forms clumps or concentrates perinuclearly. It is shown that the exposure to soot microparticles enhances apoptosis. On day 5, suppression of the proliferation of cells occurs, but the proliferation increases to the control values on day 14. Such a paradoxical increase in proliferation may be a compensatory process, maintaining the necessary level of gill function under the exposure to toxic soot. This process may occur until the gills’ recovery reserve is exhausted. In general, soot microparticles cause profound changes in the actin cytoskeleton in gill cells, greatly enhance cell death, and influence cell proliferation as described. Together, these processes may cause gill dysfunction and affect the viability of fish.

Visceral pain (VP) is the organ-derived nociception in which increased inflammatory reaction and exaggerated activation of the central nucleus of the amygdala (CeA) may contribute to this deficiency. Considering the amygdala also serves as the integration center for olfaction, the present study aimed to determine whether olfactory stimulation (OS) would effectively depress over-activation and inflammatory reaction in CeA, and successfully relieve VP-induced abnormalities. Adult rats subjected to intraperitoneal injection of acetic acid inhaled lavender essential oil for 2 or 4 h. The potential benefits of OS were determined by measuring the pro-inflammatory cytokine level, intracellular potassium and the upstream small-conductance calcium-activated potassium (SK) channel expression, together with detecting the stress transmitters that participated in the modulation of CeA activity. Results indicated that in VP rats, strong potassium intensity, reduced SK channel protein level, and increased corticotropin-releasing factor, c-fos, and substance P immuno-reactivities were detected in CeA. Enhanced CeA activation corresponded well with increased inflammatory reaction and decreased locomotion, respectively. However, in rats subjected to VP and received OS, all above parameters were significantly returned to normal levels with higher change detected in treating OS of 4h. As OS successfully depresses inflammation and CeA over-activation, application of OS may serve as an alternative and effective strategy to efficiently relieve VP-induced deficiency.

Presbyphagia is age-related changes in swallowing function, which imposes a high risk of aspiration in older adults. Considering olfactory stimulation (OS) can influence behavioral activities by modulating neuronal excitability, the present study aims to determine whether OS could improve the swallowing function of aged rats through activating the central neuronal networks and downstream muscular activities participated in the control of swallowing. Aged male Wistar rats received OS by inhaling a mixture of plant-based volatile molecules twice a day for 12 days were subjected to functional magnetic resonance imaging (fMRI) and c-fos, choline acetyltransferase (ChAT) immunostaining to detect the neuronal activities of the orbitofrontal cortex (OFC) and medullary nuclei engaged in swallowing control, respectively. The functional effects of OS on downstream pharyngeal muscle activity were examined by evaluating the dihydropyridine receptor-ryanodine receptor (DHPR-RyR)-mediated intramuscular Ca2+ expression, and analyzing the amplitude/frequency of muscle contraction, respectively. In untreated rats, only moderate signal of fMRI and mild c-fos/ChAT expression was detected in the OFC and medullary nuclei, respectively. However, following OS, intense signals of fMRI and immunostaining were clearly expressed in the orbitofronto-medullary networks. Functional data corresponded well with above findings in which OS significantly enhanced DHPR-RyR-mediated intramuscular Ca2+ expression, effectively facilitated a larger amplitude of pharyngeal muscle contraction, and exhibited better performance in consuming larger amounts of daily dietary. As OS successfully activates the neuromuscular activities participated in the control of swallowing, applying OS may serve as an effective, easy, and safe strategy to greatly improve the swallow function of aging populations.

The toxic influence of soot microparticles on terrestrial organisms has been well studied, although there is scarce data on how microparticles could affect hydrobionts. We performed a first-ever study of the short-term (5 days) impact of furnace soot (0.005 g/L) on the structural and functional features of gill cells in the Baikal Sculpin species Paracottus knerii , Dybowski, 1874. The soot samples used in the experiment were composed of small (10-100 nm) particles and larger (up to 20 mu m) aggregates. The dominant fractions of the polycyclic aromatic hydrocarbons of these microparticles were phenanthrene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzofluoranthenes, benzopyrenes, indeno[1,2,3-c,d]pyrenes, and benzo[ghi]perylene. Trace element analysis of the soot detected the presence of C, S, Si, Al, Ca, K, Mg, P, and Fe. The gill condition was assessed with electron scanning, transmission, and laser confocal microscopy. Soot induces degenerative changes in the macrostructure and surface of secondary lamellae and increases mucus production in fish gills. A decrease in mitochondrial activity, an increase in reactive oxygen species production, and an increase in the frequency of programmed cell death in gill epithelium were observed under the influence of soot. In chloride cells, an induction of macroautophagy was detected. In general, the changes in fish gills after the short-term influence of soot microparticles indicate the stress of respiratory and osmotic regulation systems in fish. The data obtained are important for forming a coherent picture of the impact of soot on hydrobionts and for developing bioindication methods for evaluating the risks of their influence on aquatic ecosystems.

This work simulates the consequences of HIREC using stone sculpins as model organisms. Sex-dependent effects of long-term noise exposure at mean sound pressure levels of 160–179 dB re 1 μPa (SPLpk–pk) were measured. We applied a multilevel approach to testing the stress response: a comparative analysis of the macula sacculi and an assessment of hematological and molecular stress responses. Noise exposure resulted in hair cell loss, changes in some cytometric parameters in blood, and an increase in the number of functionally active mitochondria in the red blood cells of males and its decrease in females, demonstrating a mitochondrial allostatic load and depletion of functional reserve. Finally, a statistically significant decrease in the telomerase activity of the auditory epithelium and a shortening of telomere length in the brain as molecular markers of stress were observed after noise exposure only in females. No significant decrease in telomerase activity and shortening of telomere length in nerve target tissues were observed in stressed males. However, we recorded an increase in the telomerase activity in male gonads. This sex-dependent difference in load may be associated with accelerated cellular aging in females and lower stress-related long-term risk in males. In this article, we discuss possible reasons for these noise-induced stress effects.

Relevance. One of the conditions for the functional outflow pathways' formation after filtering glaucoma surgeries is the uniform moisture absorption from the filtering blebs, which is provided by the blood and, possibly, lymphatic vessels of the conjunctiva. Purpose. To conduct a structural and molecular assessment of filtering blebs in patients with open-angle glaucoma (OAG) after non-penetrating deep sclerectomy (NPDS) according to OCT data, as well as ultrastructural and immunohistochemical studies. Material and methods. A clinical study of 12 patients with primary open-angle glaucoma (POAG) after NPDS was conducted. In the long-term postoperative period (12–18 months), the level of intraocular pressure (IOP) was determined, the structure of the filtering blebs using biomicroscopy and OCT of the anterior segment of the eye was evaluated, the immunohistochemical study of the filtering blebs' tissue for the expression of podoplanin and ultrastructural analysis of the samples obtained using a laser confocal microscope LSM 710 (Zeiss) was performed. In 8 cases (group 1), these were non-functional scarred filtering blebs, IOP 24.12± 2.24 mm Hg, in 4 cases (group 2) – functional filtering blebs, IOP 15.31± 4.08 mm Hg. Results. During the immunohistochemical examination of the first group patients' conjunctival samples, no vessels with characteristics of the lymphatic system were detected in any case. In each sample of the second group patients' filtering blebs, from 5 to 7 vessels with different variants of podoplanin expression were determined. Conclusion. The aqueous outflow entering the subconjunctival space through the newly created outflow pathway during glaucoma surgery is carried out at the expense of conjunctival lymphatic structures, the condition of which to a certain extent determines the success or failure of the surgery. Key words: non-penetrating deep sclerectomy; open-angle glaucoma; lymphatic outflow; filtering blebs

Algae–bacteria interactions play an important role in water ecosystems. In this work, the BS2-15 algicidal strain was isolated from the bottom sediments of Lake Baikal and identified as Bacillus mycoides on the basis of 16S rDNA sequencing, its described ultrastructure, and biochemical properties. B. mycoides BS2-15 was demonstrated to have a strong algicidal effect against a freshwater diatom culture of Ulnaria acus, inhibiting its growth and increasing frustules fragility. By analyzing the impact of bacterial filtrate onto the cells of U. acus, we demonstrated that perhaps an algicidal compound is produced by bacteria independently in the presence of diatoms in a medium. Using methods of TUNEL and confocal microscopy, we revealed that the bacterial algicidal effect on the diatom cells results in DNA fragmentation, nucleus destruction, and neutral lipid accumulation. This phenomenon highlights the complexity of algae–bacteria interactions and their potential role in regulating water ecosystem microbial populations.

Relevance. One of the conditions for the functional outflow pathways’formation after filtering glaucoma surgeries is the uniform moisture absorption from the filtering blebs, which is provided by the blood and, possibly, lymphatic vessels of the conjunctiva. Purpose. To conduct a structural and molecular assessment of filtering blebs in patients with open-angle glaucoma (OAG) after non-penetrating deep sclerectomy (NPDS) according to OCT data, as well as ultrastructural and immunohistochemical studies. Material and methods . A clinical study of 12 patients with primary open-angle glaucoma (POAG) after NPDS was conducted. In the long-term postoperative period (12–18 months), the level of intraocular pressure (IOP) was determined, the structure of the filtering blebs using biomicroscopy and OCT of the anterior segment of the eye was evaluated, the immunohistochemical study of the filtering blebs’ tissue for the expression of podoplanin and ultrastructural analysis of the samples obtained using a laser confocal microscope LSM 710 (Zeiss) was performed. In 8 cases (group 1), these were non-functional scarred filtering blebs, IOP 24.12±2.24 mm Hg, in 4 cases (group 2) – functional filtering blebs, IOP 15.31±4.08 mm Hg. Results. During the immunohistochemical examination of the first group patients’ conjunctival samples, no vessels with characteristics of the lymphatic system were detected in any case. In each sample of the second group patients’ filtering blebs, from 5 to 7 vessels with different variants of podoplanin expression were determined. Conclusion. The aqueous outflow entering the subconjunctival space through the newly created outflow pathway during glaucoma surgery is carried out at the expense of conjunctival lymphatic structures, the condition of which to a certain extent determines the success or failure of the surgery.

It is known that mitochondrial population of living organisms is heterogeneous. Using the density gradient of Percoll or sucrose, we obtained and characterized two distinct mitochondrial subfractions (named “light” and “heavy” according to their sedimentation) from three plant species (Brassica rapa, Zea mays, and Arabidopsis thaliana). Electron microscopy showed that mitochondria of a light subfraction have a poorly developed cristae structure. The respiratory control of these mitochondria was reduced; however the degree of their outer membrane integrity remained high. These data suggest that mitochondrial subfractions purified in the density gradient differ in their maturity. We carried out DNA import assays to study the ability of these two subfractions for DNA transport. We have shown that the mitochondria of light subfraction in all three plant species uptakes DNA more efficiently than the mitochondria of heavy subfraction. In addition, import of DNA with different sizes into the light and heavy mitochondrial subfractions has different sensitivity to specific inhibitors of the voltage-dependent anion channel and adenine nucleotide translocase, proteins playing a central role in DNA transport across the mitochondrial membrane. The obtained results suggest that DNA import depends on organization of the transport system in the double mitochondrial membrane influenced by the maturity of the mitochondria.

This research was devoted to studying the olfactory system adaptation mechanisms in fishes during their spawning period. For this purpose, the morpho-functional changes of supporting cells in the olfactory epithelium were analyzed by electron transmission and laser confocal microscopy. We have indicated that active mitochondria are concentrated in the apical zone of ciliated supporting cells. This position of mitochondria is important for the energy supply of cilia to enhance the olfactory mucus circulation. Moreover, there was an increase in mucous supporting cells secretory activity. Generally, identified changes in olfactory epithelium aim to raise the effectiveness of sex pheromone reception during the spawning period.

The blood of cottoid fishes has the lowest parameters that characterize the ability of heamoglobin to bind oxygen. Environmental characteristics of the species determine the morphological parameters of red blood cells and the structure of haemoglobins. In red blood cells of the Baikal yellowfin sculpin under the exposure of phenol, we revealed the damage of intracellular structures and a decrease in the number of active mitochondria by 60%.

It has been previously shown that the chemically synthesized nanocomposite of selenium with arabinogalactan (NC Se/AG) is characterized by antibacterial effect upon the agent of ring rot – gram-positive bacterium Clavibacter sepedonicus (Cms), with the NC Se/AG having no negative effect on potato plants. In the present paper, it has been found that, 1 hour after the treatment of the NC Se/AG, a substantial elevation of lipid peroxidation products was observed in potato root tissues. This supports earlier results on the increase in reactive oxygen species (ROS) production in potato root tissues under the influence of NC Se/AG. It is proposed that the increased ROS content in potato may inhibit pathogen colonization of plants. This has been tested by seeding homogenised plant tissues of various potato zones (roots, stems, shoot apex zone) onto the nutrient medium. In plants infected with Cms and untreated with the NC, the number of colony forming units (CFUs) of Cms has been shown to be numerous both in potato culture medium and in root and stem tissues. In shoot apex zone of such plants, it has been revealed, bacteria also present, but in smaller quantities. Similar data have been obtained by seeding homogenised tissues from roots and stems of potato plants treated with the NC followed by infection with Cms. However, seeding from shoot apex zones of the plants has been given 4 times less CFUs than from potato plants not treated with the NC. The effect of the NC Se/AG upon the pathogen colonization of plants appears to depend on the titre of the microorganism. In shoot apex zone of plants, characterized with small number of CFUs of Cms, the pathogen growth has been decreased. For the first time, Cms bacteria in potato plant tissues in vitro have been visualized with the aid of scanning microscopy.