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Vol 60, No 2 (2024)
Articles
Chitosan and its derivatives in agrobiotechnology, medicine and industry (RosHit 2023)
121-122
Chitosan-based functional coatings for postharvest processing of tomatoes
Abstract
The review article includes information on the use of coatings, both from chitosan itself and in combination with other polysaccharides and functional compounds, for postharvest processing, mainly of tomatoes, to extend the shelf life of harvested produce. During harvesting of fruits and vegetables, losses due to fungal infection can be as high as 50%. To prevent yield losses and preserve fruit quality, various methods of postharvest treatment are used. Currently, the most effective means used to control postharvest diseases are synthetic fungicides, but their uncontrolled use negatively affects human health and the environment. Recently, there has been a continuing trend to increase the use of natural antimicrobial agents. Such natural compounds can be chitin and chitosan, they are renewable, biodegradable, low toxicity and safe for consumers and the environment. The film-forming ability of chitosan and its antimicrobial, antioxidant properties are important for obtaining functional coatings for postharvest processing of fruits.
123-133
Preparation of antibacterial composite aerogel for biomedical purposes based on alginate-chitosan complex and calcium carbonate
Abstract
Aerogel composites were synthesized on the basis of the sodium alginate-chitosan interpolymer complex with the inclusion of calcium carbonate microparticles and supercritical drying. It is shown that the textural characteristics of materials do not depend on the morphology of calcium carbonate particles: the specific surface area of aerogels is almost the same for all materials and amounts to 380–400 m2/g. The developed porous structure of composites along with the polyelectrolyte nature determines their high water absorption — up to 110 g/g. To impart antimicrobial properties, the materials were impregnated with atranorin isolated from the lichen Hypogymnia physodes, which has a pronounced inhibitory effect on the bacterium Proteus mirabilis, which is the main causative agent of wound infections. The minimum suppressive concentration of atranorine is 1 mg/ml. The release of the main amount of atranorine aerosol material included in the matrix occurs within 4 hours and amounts to 50%.
143-150
Isolation of chitosan-melanin complex from black soldier fly adults and obtaining nanofibrous materials based on it
Abstract
The article presents the results of studying the viscosity of chitosan-melanin complex solutions from the larvae of the insect Hermetia illucens and the process of gelation in these solutions in the presence of crosslinking reagents. Chemically cross-linked nanofibers were obtained from solutions of the chitosan-melanin complex in dilute solutions of acetic acid by the method of spinneretless electrospinning. The presence of 14% melanin made it possible to reduce the concentration of acetic acid in the spinning composition.
151-157
Functional derivatives of chitosan, soluble in neutral medium as drugs and genetic material carrier: preparation and properties
Abstract
Method of chitosan modification, providing controlled addition of the quaternized block has been proposed. The structure of the products obtained were studied by FT-IR and NMR spectroscopy; their solubility and acid-base properties was characterized by turbodimetry and potentiometry, respectively. Presence about 50% of quaternized amino groups was shown to be necessary to obtain soluble products. The difference in pH-sensitivity of modified derivatives with different types of quaternized block attachment was revealed by studying their interaction with a model polystyrene sulfonate anion. The possibility of preparing complexes based on the obtained derivatives with DNA — polyplexes, stable under conditions close to physiological ones has been demonstrated. It was shown the presence of primary amino groups on the polycation chains leads to a decrease in the polyplexe size. The data obtained can form the basis for development of drug and genetic material delivery system.
The 2-stage method of chitosan modification providing controlled addition of the quaternized block has been proposed. The structure of the products obtained were studied by FT-IR and NMR spectroscopy; their solubility and acid-base properties was characterized by turbodimetry and potentiometry, respectively. The presence about 50% of quaternized amino groups was shown to be necessary to obtain soluble products. The difference in pH-sensitivity of modified derivatives with different types of quaternized block attachment was revealed by studying their interaction with a model polystyrene sulfonate anion. The possibility of preparing complexes based on the obtained derivatives with DNA, polyplexes stable under conditions close to physiological ones has been demonstrated. It is shown that the presence of primary amino groups on the polycation chains leads to a decrease in the polyplexe size. The data obtained can form the basis for development of drug and genetic material delivery systems.
134-142
Influence of chitosanon on the ability of LPS to interact with cells of the immune system
Abstract
Complexes of lipopolysaccharide (LPS) from the bacterium Escherichia coli and chitosan (CN) with a molecular weight of 5 kDa were obtained and their supramolecular organization was studied. Using atomic force microscopy, it was shown that during the formation of complexes there is a transition from the micellar structure of the original LPS to linear network structures uniformly distributed over the surface of mica. The stability of LPS-CN complexes of various stoichiometries in biological media in the presence of serum proteins was investigated. It was shown that complexes with an LPS : CN ratio of 1 : 1 in the presence of serum proteins lost their surface charge and tended to aggregate; while complexes with maximum saturation of CN (1 : 5) did not aggregate under these conditions and maintained their surface charge. The effect of CNs of different molecular weights on the ability of LPS to interact with neutrophils in human whole blood was studied. It was observed that LPS-CN complexes were capable of binding to neutrophils and entering the cell, and this ability was enhanced in the presence of serum proteins. Chitosan exhibited the ability to suppress the synthesis of the proinflammatory cytokine TNF-α, induced by LPS, not only as part of the complex but also when cells were pretreated with a polycation.
158-166
Obtaining chitosan from chitine-containing uzbekistan raw materials and research of antimicrobial properties
Abstract
The optimal conditions for the isolation of valuable natural biopolymers were revealed. chitosan from cysts of Artemia parthenogenetia in the Aral Sea and from pupae of the silkworm Bombyx mori. Chitosan (Chs) was obtained from cysts of A. parthenogenetia with a molecular weight of 89 kDa, degree of deacetylation (DDA) — 72% and solubility — 81.62%. It has been shown that it is possible to isolate Chs from silkworm pupae of sufficient purity with different molecular weights and DDA depending on the synthesis conditions and the degree of purification. Bombyx mori Chs has a higher molecular weight of 100–160 kDa, a high DDA — up to 90% and a solubility of 88%. IR spectroscopy, X-ray diffraction and elemental analysis have shown the purity of the isolated Chs from various sources. In chitin from
A. parthenogenetia cysts of the Aral Sea, two types of modifications α and β with corresponding syngonies are observed, which confirms its polymorphic structure. The antibacterial activity of B. mori Chs has been shown, which tends to expand the spectrum of suppressed bacteria with increasing concentration and have a bactericidal effect on both gram-negative and gram-positive bacteria. Chs B. mori had an immunostimulating effect on living organisms, which allows us to recommend drugs based on Chs to strengthen the immune system.
167-176
Biological activity of chitosan nanoparticle dispersions produced by fractional precipitation
Abstract
An assessment was made of the antifungal and immunomodulatory activity of dispersions of chitosan nanoparticles obtained by fractional precipitation at pH 5.0 and pH 7.5 using chitosan of different molecular weights. The dispersion of nanoparticles obtained at pH 5 has increased fungistatic activity against C. sativus and A. solani, due to the higher availability of amino groups in looser nanoparticles. This dispersion showed immunostimulating activity, increasing the resistance of wheat to dark brown spot. It was also established that the elicitor activity of dispersions of chitosan nanoparticles is significantly higher than the activity of solutions of the original polymer.
177-182
Effect of chitosan conjugates with oxycinnamic acids and Bacillus subtilis bacteria on the activity of protective proteins and resistance of potato plants to Phytophthora infestans
Abstract
The effect of chitosan conjugates with caffeic (ChCA) and ferulic (ChFA) acids in combination with Bacillus subtilis bacteria on the transcriptional activity of PR protein genes and proteome changes in potato plants during infection with Phytophthora infestans (Mont.) de Bary was studied. Plants grown from mini tubers of the Luck variety were sprayed with solutions of ChCA and ChFA, suspension of B. subtilis bacteria strains 26D and 11 VM, composites of ChCA of ChFA together with bacteria. 3 days after treatment, some of the plants were infected with P. infestans. A decrease in the degree of development of the pathogen of late blight on potato leaves in all treatment options was revealed. The maximum protective effect was manifested when plants were treated with bacteria B. subtilis strain 26D in combination with conjugates of chitosan and oxycinnamic acids. The mechanisms of increasing the resistance of potato plants to P. infestans were associated with the activation of transcriptional activity of genes encoding the main protective protein (PR‑1), chitinase (PR‑3), thaumatin-like protein (PR‑5), protease inhibitor (PR‑6), peroxidase (PR‑9), ribonuclease (PR‑10). The revealed activation of the expression of marker genes of systemic acquired resistance and induced systemic resistance under the influence of joint treatment of plants with B. subtilis and chitin conjugates with oxycinnamic acids indicate the synergistic development of protective reactions in potato plants in this variant. By the method of two-dimensional electrophoresis of S. tuberosum leaf proteins followed by MALDI-TOF analysis, 12 proteins were identified, the presence of which in the leaves differed depending on the variant of the experiment. In all treatment variants, suppression of serine-threonine protein phosphatase activity was observed, reflecting the development of the hypersensitivity reaction. Different variants of the experiment formed weakly expressed clusters, which indicates multiple mechanisms of regulation of the synthesis of protective proteins involved in the reaction to treatment with bacteria, chitosan conjugates and infection with P. infestans.
183-192
Effect of Bacillus subtilis in combination with chitosan salicylate on peroxidase and catalase activity in B. sorokiniana infected wheat
Abstract
The aim of the work was to study the effect of Bacillus subtilis strains VKM B‑2604D and VKM B‑2605D which form the basis of the Vitaplan biological product, and their combinations with chitosan salicylate on antioxidant defense enzymes in the process of formation of resistance of wheat plants to infection with the dark brown blotch pathogen Bipolaris sorokiniana. In wheat plants treated with B. subtilis strains and their combinations with chitosan salicylate, upon subsequent infection, catalase and peroxidase are activated, which regulate the intensity of oxidative stress induced by the introduction of the pathogen. Taking into account the data obtained by us, it can be assumed that the increase in plant resistance to the pathogen is realized through the control of the activity of antioxidant enzymes (in particular, catalase, peroxidase), which maintain the concentration of H2O2 at the level necessary for the neutralization of the phytopathogen in tissues, including the direct destruction of the invading pathogen and / or activation of crosslinking and lignification of the cell wall. These processes strengthen the cell wall and help contain the spread of the pathogen in the plant. At the same time, protective reactions are also switched on, leading to the development of induced resistance in wheat plants to dark brown spotting, which manifests itself in a decrease in the development of the disease by 25–45% relative to the infected control in the treated plants. The obtained results indicate that the combination of active strains of microorganisms-antagonists of plant pathogens and chitosan salicylate is promising for increasing the biological efficiency and expanding the spectrum of action of the developed prescription forms of biological products.
193-204
The biological efficiency of multifunctional complexes based on Bacillus subtilis strains and chitosan salicylate in wheat cultivation
Abstract
The influence of multifunctional complexes capable of causing a growth-stimulating effect on plants and inhibiting the development of a wide range of diseases on the Leningradka 6 spring soft wheat cultivar (k-64900) was investigated. In the research, it was found that the application of multifunctional complexes based on the Bacillus subtilis bacterial strains and 0.1% chitosan salicylate in wheat cultivation led to a significant decrease in the incidence of plant diseases: yellow and brown rust, powdery mildew, root rot and caused an increase in morphometric productivity indicators. This tendency was associated with a significant influence of multifunctional complexes on the increase in the number of primary and nodal roots; the length of nodal roots; productive bushiness; the number of spikelets per spike; the grains weight per spike. However, the effectiveness of protective and stimulating wheat treatments depended on the complex of natural and climatic factors of wheat vegetation seasons.
205-218