Natural Polymeric Matrices Research Articles

Effect of Nanopriming with Selenium Nanocomposites on Potato Productivity in a Field Experiment, Soybean Germination and Viability of Pectobacterium carotovorum

In recent decades, the use of nanocomposites (NCs) in crop production has been actively studied. We have previously shown that chemically synthesized selenium nanocomposites (Se NCs) based on natural polymeric matrices of arabinogalactan (Se/AG NCs), carrageenan (Se/CAR NCs), and starch (Se/ST NCs) stimulated the growth and development of potatoes in vitro and had an antibacterial effect against the phytopathogen Clavibacter sepedonicus. It is important to confirm that the results obtained in the laboratory are also reproducible in the field conditions of crop cultivation. In addition, the applications of NCs can be expanded if a wider range of their biological activity is revealed, and the effect on other types of cultivated plants and phytopathogens is shown. In this regard, the purpose of this research was to study the effect of nanopriming with Se NCs on the productivity of potatoes in a field experiment, the germination of soybeans, and the viability of the phytopathogen Pectobacterium carotovorum under in vitro conditions. The study included the use of traditional methods of conducting a field experiment in natural growing conditions, also using microbiological cultures and studying the bacterial profile from the endosphere of potato tubers by the imprint method, germinating Glycine max L. soybean seeds after nanopriming in Petri dishes, followed by the measurement of morphometric and biochemical parameters such as the activity of antioxidant enzymes and content of diene conjugates. Based on the results of field experiments, it was found that the preplant treatment of tubers with Se/AG and Se/CAR NCs stimulated a significant increase in the number of stems in potato plants and tubers per plant, but for Se/AG NC, the increase was observed only in 2020 and 2022, and the stimulating effect of Se/AG and Se/CAR NCs on the weight of tubers was observed only in 2020. In the yield structure, the proportion of marketable seed tubers was increased under the influence of all Se NCs. Endosphere cultures from tubers showed that bacteria were present in only 56% of the tubers in the control, while 78% of the tubers obtained from plants grown from seed tubers treated with Se/AG NC and 100% of the tubers from plants grown from seed tubers treated with Se/ST and Se/CAR NCs contained bacteria. The bacteria were represented by both spore-forming Gram-positive and Gram-negative bacteria of various sizes. The results presented in this article and previously published data showed that the maximum diversity of bacteria was observed after treatment with Se/ST NC. Experiments on potatoes showed that Se/AG NC had the greatest biological effect. In addition, the growth-stimulating effect of these NCs on the biomass of the roots of soybean seedlings was shown. It activated the antioxidant enzymes and reduced the level of diene conjugates (DCs), the amount of which increased significantly after seed biopriming with the phytopathogen Pectobacterium carotovorum. The antibacterial effect of Se/AG NC in relation to the P. carotovorum was observed as a reduction in the growth of the bacterial culture, biofilm formation, and dehydrogenase activity of cells. Thus, it has been shown that Se/AG NC has a stimulating effect on such agriculturally important crops as potatoes and soybeans, as well as an antibacterial effect against Gram-negative and Gram-positive phytopathogenic bacteria.

Влияние нанокомпозитов селена в природных полимерных матрицах на антиоксидантный статус растений картофеля in vitro

In the present work researches on influence of chemically synthesized nanocomposites of selenium (NC) in natural polymeric matrices - arabinogalactan (selenium content 6.4%) and starch (selenium content 1.2%) on a condition of antioxidant system of potato plants are presented. It is known that during abiotic or biotic stress, lipid peroxidation products (POL) are formed in plant tissues and the content of reactive oxygen species (ROS) in plant tissues increases, which leads to dysfunction of the plant cell membrane, inhibition of biochemical processes in the plant cell and, as a consequence, cell death. Therefore, the main task of this work was the study of NC for antioxidant activity. Studies have been conducted on the effect of NC on the content of reactive oxygen species (ROS) in potato root tissues, the activity of peroxidase enzyme in the tissues of roots and leaves, and the content of lipid peroxidation products (LPO) - diene conjugates (DC) and malondialdehyde (MDA) in the tissues of roots and leaves of potatoes. Studies were conducted on uninfected potato plants of Lukyanovsky variety (susceptible variety) and infected with phytopathogenic bacterium Clavibacter sepedonicus (Cms) in vitro. The results of the study showed that NC affect the antioxidant system of plants during infection. NC action reduced the release of ROS, reduced the content of LPO products, and also reduced the activity of the enzyme peroxidase. Studies of the primary stress indicator – DC, it was found that only NC Se/Ag had a negligible effect when processing non-infected potato plants, but when at the same time, both studied substances reduced the indicator in the variant with infected plants. Thus, it was found that NC reduces the stress load on the infected plants, reducing cell damage by products of oxidative stress. Perhaps this effect is related to the nature of polysaccharide matrices and the size of encapsulated selenium nanoparticles in them and its toxic effect. Combining all the data obtained, we can talk about the effectiveness of NC in the fight against bacterial diseases of cultivated plants and assume its use as an effective and safe remedy against them.

Acetylated cashew gum-based nanoparticles for the incorporation of alkaloid epiisopiloturine.

The natural alkaloid epiisopiloturine has recently become the focus of study for various medicinal properties, particularly for its anti-inflammatory and antischistosomal effect. The incorporation of active molecules in natural polymeric matrices has garnered increasing interest during recent decades. A new derivative of cashew gum successfully obtained by gum acetylation has shown great potential as a carrier in controlled drug release systems. In this work, epiisopiloturine was encapsulated in acetylated cashew gum nanoparticles in order to increase solubility and allow slow release, whereas the morphology results were supported by computer simulations. The particles were produced under a variety of conditions, and thoroughly characterized using light scattering and microscopic techniques. The particles were spherical and highly stable in solution, and showed drug incorporation at high levels, up to 55% efficiency. Using a dialysis-based in vitro assay, these particles were shown to release the drug via a Fickian diffusion mechanism, leading to gradual drug release over approximately 6 h. These nanoparticles show potential for the use as drug delivery system, while studies on their potential anti-inflammatory action, as well as toxicity and efficacy assays would need to be performed in the future to confirm their suitability as drug delivery candidates.

Effect of temperature gradients on the activity of enzymes immobilized on natural polymeric matrices

The invertase activity has been studied in the presence of a temperature gradient by interposing the enzyme onto a polymeric membrane between two solutions, kept at different temperatures. The enzyme activity has been determined as a function of average temperature (Tav) and of the applied temperature difference ΔT=Tw − Tc. It has been found that in the non-isothermal state the activity is higher than in comparable isothermal conditions, the increase being proportional to the applied transmembrane temperature difference. Mathematical relationships between the isothermal and non-isothermal enzyme activity have been derived. The rapid product removal from the enzyme complex by means of a process of matter transport associated to the flux of thermal energy is indicated as the way by which the temperature gradient affects the enzyme activity. Some practical applications are suggested.