The present study is aimed at the directed synthesis of a new ternary molybdate K₅Pb_0.5Zr_1.5(MoO₄)₆ isostructural to K₅Pb_0.5Hf_1.5(MoO₄)₆ by solid-phase reaction within the temperature range of 350–550 °С (for 100 h). The compound crystallizes in the rhombohedral system with the space group R3̅  and unit cell parameters of a = 10.6604(2) Å, c = 37.9769(9) Å, and V = 3737.6(2) ų. The structure was refined using the Rietveld method. The atomic positions were refined in the isotropic approximation, with soft constraints on Mo–O distances and O–Mo–O bond angles. The crystal structure constitutes a 3D scaffold comprising PbO₆ and ZrO₆ octahedrons and MoO₄ tetrahedrons sharing oxygen vertices. The thermal expansion of K₅Pb_0.5Zr_1.5(MoO₄)₆ was studied via high-temperature X-ray powder diffraction. The calculated thermal expansion coefficients along both crystallographic axes remain positive over the entire temperature range. In this case, the value of α_a remains constant, while that of α_c increases with rising temperature. The obtained ternary molybdate belongs to materials with high thermal expansion (α_V = 60×10^-6 °С^-1). The significant anisotropy in the crystallographic direction c can be attributed to the soft K–O and Pb-O bonds. The electrical conductivity of K₅Pb_0.5Zr_1.5(MoO₄)₆ was studied via impedance spectroscopy within the temperature range of 30–500 °С; at 500 °С, the conductivity amounted to 0.7×10^-4 S/cm, with E_a = 0.59 eV.

One of the directions in the development of organic chemistry is the synthesis of biologically active compounds, including those with bactericidal activity, based on available petrochemical raw materials. In order to expand the library of bioactive compounds containing a 1,3-dioxacyclane fragment, the synthesis of derivatives of 5-acyl-5-isopropyl-1,3-dioxane – 1-(5-isopropyl-1,3-dioxane-5-yl)ethanol and (5-isopropyl-1,3-dioxane-5-yl)ethyl phenyl carbamate was carried out. The effect of synthesized compounds containing a 1,3-dioxacyclane fragment on the growth of strains of gram-negative and gram-positive bacteria, lower fungi Candida albicans was studied. It was found that 2-methyl-2-ethyl-4-chloromethyl-1,3-dioxolane, containing a chloromethyl group, has an antimicrobial effect against gram-positive and gram-negative test cultures and weak antifungal activity (minimum inhibitory concentration is 100 μg/mL) against lower fungi Candida albicans. 1-(5-Isopropyl-1,3-dioxan-5-yl)ethanol exhibits antifungal activity (minimum inhibitory concentration is 2 μg/mL) and sharply reduces antimicrobial activity against Klebsiella pneumonia, Staphylococcus aureus, Enterobacter aerogenes (minimum inhibitory concentration is 100 μg/mL), in contrast to the structurally similar 2-methyl-2-ethyl-4-hydroxymethyl-1,3-dioxolane, which did not show similar properties. 5-Acyl-5-isopropyl-1,3-dioxane, containing a carbonyl group in its structure, showed antimicrobial activity (minimum inhibitory concentration is 25 μg/mL) against gram-negative test cultures, with the exception of Pseudomonas aeruginosa. Heterocycles (2-methyl-2-ethyl-4-chloromethyl-, 2-isobutyl-2,4-dimethyl-, 2-methyl-2-isobutyl-4-chloromethyl- and 2-methyl-2-isobutyl-4-hydroxymethyl-1,3-dioxolane) at concentrations up to 100 μg/mL did not inhibit the vital activity of the studied bacteria and lower fungi. The results obtained show the prospect of continuing the search for new antimicrobial and antifungal drugs of the series of 1,3-dioxacycloalkanes, the structure of which is fundamentally different from the known antibacterial drugs.

This study evaluated the antifungal and antioxidant activities of earthworm (Perionyx excavatus) powder extracts using different solvents including 80% ethanol, 50% ethanol, and distilled water. The extraction efficiencies ranged from 18.5 to 21.2%, while total protein contents ranged from 64.8 to 67.5%. Notably, the aqueous extract exhibited the highest values in both extraction efficiency and total protein content. Thin-layer chromatography analysis revealed the presence of amino acids and peptides with Rf values ranging from 0.42 to 0.65. Fourier-transform infrared spectroscopy spectra displayed characteristic peaks associated with protein structures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated protein compositions primarily below 50 kDa molecular weight in the extracts, particularly with the 80% ethanol extract predominantly consisting of proteins below 30 kDa. Antifungal tests against Candida albicans demonstrated the highest efficacy with 80% ethanol extract, exhibiting an inhibition zone diameter of 13.3 mm and a minimum inhibitory concentration of 75 mg/mL. Additionally, the extracts showed DPPH and ABTS radical scavenging activities, with 80% ethanol extract displaying the highest antioxidant potential with IC50 values of 231.3 μg/mL for DPPH assay and 208.9 μg/mL for ABTS assay. In conclusion, earthworm powder extracts exhibited significant biological activities, rendering them promising candidates for pharmaceutical and cosmetic applications.

The present study examines reaction products in the solution of antibiotic cefotaxime with succinic anhydride, maleic anhydride copolymer, and dialdehyde wheat starch. The reaction of cefotaxime with succinic anhydride is shown to produce succinamide; to maleic anhydride copolymer, cefotaxime is likely to bind via noncovalent intermolecular interactions. An azomethine derivative of oxidized polysaccharide with cefotaxime was found to form; the molar ratio of initial glucosidic units in starch, unreacted dialdehyde units, and those bonded to cefotaxime through the azomethine linkage is 0.204:0.606:0.19. Drug release from the obtained matrix form was studied in different biorelevant media (saline, phosphate buffer, and Tris-HCl buffer). The amount of cefotaxime released in ten hours was found to approach 100%. Its release proceeds in two phases. In the first phase (1–2 h), 35 (pH 7.14) to 70% (pH 7.4–8.0) of the drug substance is released into the solution, followed by a significant decrease in the release rate. The processing of kinetic data using the first-order and Higuchi equations revealed consistency with both models. The obtained rate constants increase in proportion to the solution pH. It is assumed that first, the azomethine bond hydrolysis occurs with the release of cefotaxime molecules from the polymer matrix; then, the macromolecules of oxidized starch residing on the surface are dissolved; due to an increase in the viscosity of the solution layer surrounding the conjugate particle, the hydrolysis rate decreases. In general, cefotaxime release from the conjugate proceeds as a pseudo-first-order reaction accompanied by diffusion processes.

Recent years have seen a rapidly growing interest in the use of plant-isolated bioactive compounds as ingredients in functional food and pharmaceuticals. It is known that food matrix, molecular size, external factors, and gastrointestinal environment can interfere with the bioavailability and absorption of such bioactive compounds in the body. The protection of specified compounds via nanoencapsulation technology can improve their stability. The present work is aimed at studying the application of a delivery system based on emulsion micro- and nanocapsules in the protection of bioactive compounds (essential oils), as well as examining the effect of ultrasound of different amplitudes on the stability of emulsion microcapsules in the protein/pectin system with essential oil. The following parameters were determined: average size of obtained microcapsules, zeta potential, specific surface area of the particles, and viscosity of the disperse system. Ultrasound is shown to initiate the formation of a pectin layer, with the charge density varying on the surface of emulsion particles depending on the applied ultrasonic force. The article presents the optimal ultrasound amplitude for the formation of medium-sized particles having a high specific surface area of 32967 cm2 per 1 mL of the emulsion. The obtained nano- and microparticles with essential oil exhibit good antimicrobial, antifungal, and antiviral activities. The developed delivery systems based on food biopolymers with identified characteristics may well meet the requirements of the antibacterial drugs market and find their application in the field of functional food development.

Xyloglucan endotransglycosylases are hydrolytic cell wall enzymes that are involved in the regulation and promotion of plant growth. Overexpression of genes encoding xyloglucan endotransglycosylases can have a positive effect on the growth and stress tolerance of transgenic plants; however, the mechanisms of such influence remain poorly understood. This study was aimed at creating transgenic tobacco plants with overexpression of the PtrXTH1 gene encoding aspen xyloglucan endotransglycosylase, as well as conducting a morphophysiological analysis of their roots under abiotic stress. The transgenic tobacco plants were characterized by an increased root length as compared to wild plants, both under optimal conditions and in response to salinity (100 mM sodium chloride), low temperature (12 °C), and cadmium contamination (200 μM cadmium acetate). The area of root parenchyma cells in transgenic tobacco plants is larger as compared to wild plants only under the effect of cadmium acetate, whereas under normal conditions and under low-temperature and salinity stress, no difference in cell size was observed. The PtrXTH1 gene overexpression contributed to the increased total antioxidant capacity in the roots, as well as a higher content of proline, water-soluble sugars, and oxidized and reduced glutathione, in the context of the three stress factors. Thus, the PtrXTH1 transgene stimulates the growth of tobacco roots under normal and abiotic stress conditions, which is accompanied by positive changes in the antioxidant system.

Biotechnological transformation of plant materials constitutes one of the most promising industrial processes for obtaining high-value products from inexpensive plant materials. The article analyzes the biotransformation of giant miscanthus (Miscanthus × giganteus) into high-value bacterial nanocellulose from the feedstock to the final product, i.e., presents the complete cycle of plant material processing. First, the chemical composition of giant miscanthus biomass was determined, and the content of cellulose was found to be 54%. After that, biotransformation was performed in three stages: in the first stage, the giant miscanthus biomass was pretreated using four methods; then, the obtained substrates were subjected to enzymatic hydrolysis under the same conditions, and carbohydrate growth media were obtained; in the final stage, bacterial nanocellulose was biosynthesized in the obtained growth media using Medusomyces gisevii Sa-12 symbiotic culture. The chemical pretreatment with dilute solutions of nitric acid and sodium hydroxide was found to be extremely effective and increase the reactivity to enzymatic hydrolysis by 28–31 times as compared to native miscanthus. It is shown that for the production of bacterial nanocellulose from giant miscanthus, biomass should undergo one-stage pretreatment with a dilute nitric acid solution. In this case, the substrate yield from the feedstock (for subsequent hydrolysis) amounts to 50%, the extraction of reducing sugars from miscanthus biomass is maximum (65.2%), and the yield of bacterial nanocellulose is 1.1–1.3 times higher than for the other three biomass pretreatment methods.

Low temperature is an important factor limiting plant viability and productivity. Along with other stresses, low temperatures increase the generation of reactive oxygen species, which are signaling molecules that can damage cell components. As well as representing one of the main targets of oxidative damage during stress, mitochondria represent a significant source of reactive oxygen species. Plant mitochondria have a large number of enzymes providing alternative electron transport pathways, many of which are activated under stress. Our aim was to assess the effect of low positive temperatures and increased expression of the heterologous gene NDB2 (alternative external NADH dehydrogenase of mitochondria) on the generation of reactive oxygen species, which involve an alternative respiratory chain in mitochondria and the expression of stress proteins under lighting conditions in Nicotiana tabacum tobacco leaves. In the leaves of tobacco plants with increased expression of the Arabidopsis thaliana NDB2 (AtNDB2) gene, a decrease in reactive oxygen species production was observed under normal and low temperature conditions. The results indicate that the heterologous Arabidopsis thaliana NDB2 gene is involved in increasing the activity of the alternative electron transport chain in mitochondria, which reduces the level of reactive oxygen species generation and affects the content of stress proteins under normal and low-temperature exposure.

Studies on the producers of L-lactic acid are highly relevant at the moment due to the broad scope of its applications. This study was aimed at selecting culture parameters for a milk-derived thermophilic strain of Weizmannia coagulans that is capable of producing L-lactic acid. It was found that the strain productivity depends on the culture temperature, stirring rate, medium pH, used neutralizing agent, and glucose concentration. The culture in flasks and a fermenter revealed that in 56 hours, the strain is capable of producing up to 80.4 g/L of lactic acid at a corresponding average productivity of 1.44 g/(L×h) with a conversion of about 99%. The most optimal parameters to achieve the highest indicators were a temperature of 50 °С, medium pH of 6.5, and a stirring rate of 150 rpm. This strain was shown to be uninhibited by high glucose concentrations; conversely, it exhibited higher productivity at glucose concentrations of 100–120 g/L in the medium. Among the neutralizing agents used for pH adjustment, the Ca(OH)2 agent was selected, which has the least effect on the size of producer cells during fermentation and whose by-products are the least toxic. The obtained results indicate that further studies on the metabolic properties and genetic modification of this strain are required in order to increase productivity, reduce the inhibitory effect of the target product on the metabolism of the producer, and obtain elevated lactic acid titers in a short fermentation time.

The article presents the culturing of nine microalgae strains from the IPPAS collection of IFR RAS using components of the aqueous phase of the excessive activated sludge hydrothermal revitalization process as a substrate. In order to select the most promising cultures, their growth characteristics and efficient removal of NH₄⁺ ions, PO₄^3- and organic compounds were studied. All the studied cultures are shown to be able to utilize components of the aqueous phase as a nutrient substrate. The highest specific growth rate of 0.92 day^-1 was observed in the strain Chlorella sp. IPPAS C-1210. However, the Parachlorella kessleri IPPAS C-9 and Chlorella minutissima IPPAS C-123 strains were also promising in terms of their efficiency of pollutant removal from the medium: efficiency of ammonium nitrogen assimilation was 78 and 81%, while phosphate ion assimilation was 89 and 91%, respectively. The biomass composition of C-9 and C-123 cultures was investigated, mainly consisting of polysaccharides – at 41 and 44% – and proteins – at 31 and 25% of the total mass, respectively. A high degree of neutralization of the medium was additionally achieved as a result of consecutive two-stage purification of the aqueous phase of the process of hydrothermal revitalization of excessive activated sludge with the use of microorganisms-destructors (Paenarthrobacter nicotinovorans and Comamonas testosteroni) and the studied microalgae cultures. During 17 days of the purification process, the concentration of ammonium ions decreased from 289.8±14.9 to 51.1±2.2 mg/dm³, phosphates from 116.3±8.1 to 11.3 mg/dm³; the overall efficiency of the process of pollutants removal from the aqueous phase was up to 90%.

The study examined the concentration dynamics of naphthalene, with its initial concentrations of 1, 2, and 3 g/L in synthetic wastewater. The initial number of Bacillus megaterium MK64-1 cells in the medium amounted to 1.7×10⁷ CFU/mL. On day 14 of the experiment, the concentration of naphthalene decreased to hundredths of a gram, while the microbial count increased to 10⁹ CFU/mL (at the initial naphthalene concentrations of 1 and 2 g/L) and 10¹¹ CFU/mL (at the initial naphthalene concentration of 3 g/L). After 14 days, the medium pH decreased by an average of 0.7 units (from 8.56 to 7.86) in both test and control media, with the addition of a microbial suspension. During this time, the redox potential of the medium increased by an average of 70 mV in the test media. Quite a strong direct correlation (p < 0.05) was found between the initial concentration and the amount of pollutant degraded by bacteria. The determination of dehydrogenase activity in Bacillus megaterium by means of two methods (with 2,3,5-triphenyltetrazolium chloride and methylene blue), as well as microbial sensitivity to hydrocarbon concentrations of 1, 2, and 3 g/L via the disk-diffusion method, showed no toxic effect of the analyzed pollutant concentrations on bacteria under the experimental conditions. The obtained results indicate the ability of Bacillus megaterium strain MK64-1 to biodegrade naphthalene.

The development of new promising materials of three-dimensional structure from available bioresorbable, biointegrable and biocompatible polymers is in demand and relevant in connection with the intensive development of regenerative medicine. In this work, hydrogels of the grafted copolymers of methyl methacrylate/butyl acrylate onto a mixture of collagen and pectin were obtained during photocatalysis in the presence of a complex oxide RbTe_1.5W_0.5O₆. The characteristics of the synthesis products were obtained by gel penetrating chromatography, elemental analysis, electron microscopy, and biological biocidality tests. The collagen content in an amount of less than 40%, the microstructure of the polymer in the form of a fine-mesh, and the biocidity of the sample films were established. The polymer product was identified on the catalyst surface after the separation of the oxide powder from the aqueous dispersion. The main advantage of such materials is the unique combination of properties of their components assembled into a specific structure. The advantages of the obtained material include, among other things, the environmental advantage of the initial components - natural renewable raw materials: collagen was isolated from cod processing waste, pectin from fruit and vegetable processing waste.

The entomopathogenic strains of Bacillus thuringiensis are used in the development of new-generation biopreparations against leaf-eating insects. The present study was aimed at analyzing the frequency of cry-like genes in the strains and at identifying a promising strain for the development of an entomopathogenic biopreparation on its basis. The study materials included the entomopathogenic strains of Bacillus thuringiensis obtained from the Crimean microorganism collection of the Crimean Agricultural Research Institute. The entomopathogenic effect of promising strains was studied in laboratory experiments on Coleoptera and Lepidoptera larvae. The following strains of Bacillus thuringiensis were identified as the most promising, i.e., containing at least four toxin genes: 708 (cry1, thuE, cry7-8, cry11), 942 (cry1, thuE, cry11, vip), 949 (cry1, thuE, cry4, cry7-8), 989 (cry1, thuE, cry11, vip), 0162 (cry1, thuE, cry11, vip), 0307 (cry1, thuE, cry4, cry7-8), 0308 (cry1, thuE, cry4, cry7-8), 0363 (cry1, thuE, cry5, cry11) и 0371 (cry1, thuE, cry9, cry11). The isolated strains of Bacillus thuringiensis 0162, 0307, 0363, and 0371 were found to have a high entomopathogenic effect on the larvae of the Colorado potato beetle and elm-leaf beetle (88.3–100%), as well as the caterpillars of ermine moth, cabbage moth, brown-tail moth, and fall webworm (92.3–100%). It is shown that Bacillus thuringiensis strain 0371 goes through all traditional stages of development and exhibits complete release of crystals and spores from the sporangium within 45–48 h. Thus, strain 0371 can be used to develop specifications for manufacturing a plant protection biopreparation.

The potato microbiome has a significant impact on plant growth and development. In order to affect this microbiome, agriculture can use various biopreparations on the basis of soil microorganisms. Being vulnerable to pathogens and drought, potato plants are particularly useful in the development of biopreparations. Special attention is given to Rhodococcus bacteria due to their ability to clean contaminated soil and stimulate plant growth. The present study was aimed at examining the effect of Rhodococcus qingshengii VKM Ac-2784D on bacteria isolated from potato endo- and rhizosphere. It is known that only a small fraction of microorganisms within the plant microbiome can be obtained in pure culture. Given these limitations, it was possible to isolate over 70 endophytic strains without the use of selective media and show that many of them are sensitive to the presence of a biopreparation component on the basis of Rhodococcus qingshengii VKM Ac-2784D. The metagenomic study indicates a change in the composition of the microbial community following treatment with the biopreparation. The experiments also show that the bacteria remain sensitive to Rhodococcus even in the presence of other competing strains. In general, the study results indicate a modulating effect of the biopreparation on the potato microbiome without phytotoxicity. The findings are important for understanding the effect of the biopreparation on the microbial composition of soil and potato plants, as well as for developing effective strategies for the use of microorganisms in agriculture.

The conducted study was aimed at validating a technology for processing a deep-sea fishing species of the Pacific Basin (giant grenadier) using the sous-vide method and enzymatic rearrangement of muscle tissue. The physicochemical properties of muscle tissue at different processing stages were determined, as well as changes in protein fractions; the proposed technology and conventional heat treatment methods were compared; rational process parameters were established; the stability of finished products during storage and their safety characteristics were analyzed. With the use of different processing methods (cooking in water, steam treatment, and sous-vide), the quality indicators reflect a decrease in density, destruction of the muscle tissue structure, and loss of consumer appeal of finished products in all cases. For the sous-vide method, the process losses were significantly lower, which corresponded to a lower degree of protein denaturation. In order to achieve the required quality indicators, giant grenadier muscle tissue was preliminarily rearranged using transglutaminase to form cross-links between protein molecules. Gelatin and chitosan lactate served as additional substrates, enhancing the polymerization of endogenous proteins. The products maintained their structural integrity with an increase in strength. The paper examines the effect of transglutaminase on the binding of sarcoplasmic and myofibrillar proteins with the formation of macromolecular conjugates. With six-month freezer storage of samples, no significant changes in the physicochemical parameters were observed, including the degree of protein denaturation and the strength of finished products. During storage, microbial contamination did not exceed 102 CFU/g for all samples. The addition of chitosan lactate significantly reduced the growth of psychrophilic microorganisms.

Cellulases whose temperature optimum is shifted to extremely high or low values are of particular interest since they allow for greater flexibility in controlling the technological conditions of their industrial use. Nevertheless, the mechanisms that explain enzymatic adaptations to limiting temperatures are not fully established. The study was aimed at using bioinformatics methods to examine how the structure of microbial endoglucanases depends on two factors: the belonging of producers to different taxonomic groups of higher rank (bacteria, fungi, and archaea) and the temperature optimum of their habitat (psychro-, meso-, and thermophiles). Enzymes retrieved from Uniprot and GenBank were analyzed via pairwise and multiple sequence alignment, pairwise structural alignment, and comparison of amino acid profiles. It is shown that the sequences cluster according to the systematics of producers and do not contain patterns associated with adaptations to temperature conditions. However, the amino acid profile of proteins depends also on the temperature conditions of the microbial habitat: the frequencies of some amino acids (E, I, Y, D, and Q) differ significantly in enzymes with different temperature optima. The study also identified a set of enzymes with low sequence identity but high similarity of 3D structures. This set includes enzymes from related taxa but with different temperature optima, as well as endoglucanases from microorganisms that are systematically distant while living under similar temperature conditions. Among other things, the possible mechanisms of the observed differences between the identity scores of different structural levels of protein are discussed.