Vol 10, No 4 (2020)
Chemical Sciences
Research into complexes of triethanolamine with ZnCl2 and CdCl2 using NMR Spectroscopy and Quantum Chemistry methods
Abstract
Complexes of triethanolamin with ZnCl2 and CdCl2 were studied using the methods of quantum chemistry and NMR spectroscopy. Triethanolamine complexes are prone to ligand exchange, which make them suitable as metal transporters. Therefore, research into the biological action of such compounds is of particular importance. 1H and 13C NMR spectra were recorded using a Bruker DPX250 pulsed spectrometer operated at 298 K. Non-empirical quantum-chemical calculations were performed by the B3LYP method using the Gaussian 09 software package. Changes in the chemical shifts and spin-spin coupling constants during the formation of triethanolamine complexes with heavy metals were studied. The obtained experimental data indicate that changes in the NMR spectrum shifts are accompanied by an increase in the spinspin coupling constants, with the 1J(C, H) constants of the methylene group associated with nitrogen being the most significant. On the basis of the conducted NMR spectrum analysis, the authors propose a scheme for describing the structure and intermolecular dynamics of the complexes under study. In order to elucidate the observed changes in the NMR spectra of triethanolamine in the process of complex formation, a series of quantum-chemical calculations was carried out. Three states corresponding to mono-, bi- and tricyclic structures were taken into account. According to the obtained theoretical and experimental results, the complexes under study are characterized by intermolecular metabolic processes that lead to the averaging of NMR signals from various compounds existing in the solution. For triethanolamine complexes with CdCl2, the existence of bi- and tricyclic forms is equally probable. For triethanolamine complexes with ZnCl2, the tricyclic form seems to be more beneficial.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):548-555
548-555
Computer simulation of the sorption of heavy metal ions by a sulphur-containing modified zeolite
Abstract
This paper considers complex-chelating and complex-coordinating mechanisms of sorption of heavy metal ions, which have an affinity for sulphur atoms, by sulphur-containing sorbents. The advantages and disadvantages of sulphur-containing sorbents obtained by modification of natural materials are shown. The STATGRAPHICS Plus environment was used to analyse the applicability of classical linearized Freundlich and Langmuir equations for describing the adsorption isotherms of zinc, copper and nickel ions from aqueous solutions by the Kholinsky zeolite modified with a sulphur-containing polymer. It is shown that the classical Freundlich equation accurately describes the sorption isotherms of Zn2+ and Ni2+ by the sorbent under study at the aqueous solution temperatures of 20-40 °C and 20 °C, respectively. The use of the Freundlich equation to describe the sorption isotherms of Cu2+ is impractical due to its low accuracy. For this purpose, regression models for approximating experimental data or a linearized Langmuir equation are more suitable. It is shown that the Langmuir equation describes 99.35, 98.41 and 92.12% of the experimental values of Cu2+ sorption at the aqueous solution temperatures of 20, 40 and 60 °C, respectively. It was established that an increase in the temperature of the model solution leads to an increase in the equilibrium constant and equilibrium adsorption capacity, at the same time as decreasing the accuracy of isotherm description. The sorption isotherms of Zn2+ and Ni2+ do not obey the Langmuir equation, which can be explained by the Pearson acid-base concept (HSAB). According to this concept, Zn2+ and Ni2+ ions are acids of intermediate hardness, while Cu2+ ions refer to ‘soft’ acids capable of forming the strongest compounds with ‘soft’ bases (polymer sulphur atoms). Zn2+ and Ni2+ ions bind not only to sulphur atoms, but also to oxygen atoms (‘hard’ base) of the zeolite matrix, thus moving along the sorbent surface in search of sites more convenient for coordination. Therefore, for Zn2+ and Ni2+ ions, one of the basic principles of the Langmuir theory is violated, i.e. localization of the sorbate on the sorbent surface. Apparently, it is for this reason that the Langmuir equation is not applicable for describing the Zn2+ and Ni2+ sorption.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):564-572
564-572
Acid-base properties of imidazo[2,1-b] tiazole and tiazolo[3,2- а] benzimidazole derivatives
Abstract
For over 30 years, azomethine groups have been attracting significant research interest due to their high electrophilicity formed under the influence of strong electrophilic substituents. The combination of a polyhalidealkyl group and functional substitutes in close proximity to the azomethine bond reveals a wide range of possible chemical transformations, one of which is the production of heterocyclic derivatives. Since heterocyclic compounds are of interest in terms of their medical and synthetic prospects, research into the NH-acidity of these compounds is highly relevant. Information on the acid-base properties of such compounds is useful for predicting their reactivity and physical-chemical properties. The potentiometric titration method was used to determine the dissociation constants of the substances under study. As a result, titration curves with a different number of dissociation stages (their number was determined by the number of NH-groups) were obtained, which showed a clear jump in the potential of the indicating electrode. The experimental determination of the acid-base behaviour of the synthesized sulphonylamine-substituted imidazo[2,1-b]tiazoles and thiazolo[3,2-a]benzimidazoles was carried out in dimethylsulphoxide medium. The semi-neutralization potentials were determined using titration curves. A relationship between acidity constants (pKA) and semi-neutralization potentials was determined. The pKA =f (E1/2) dependence allows the constants of NH-acidity for newly synthesized compounds in dimethylsulphoxide medium to be predicted. The statistical range of the conducted potentiometric titration was determined. The obtained dissociation constants showed a high level of intermediate precision. The variation coefficients ranged from 0.34 to 1.48%. The PASS software was used to calculate the potential of biological activity (Pa) of the compounds under study. The relationship between NH-acidity and biological potential is still ambiguous.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):573-580
573-580
Synthesis and using of 10-hydroxy-3,3,6,6-tetramethyl-9-(4-hydroxy-3-methoxyphenyl)-1,2,3,4,5,6,7,8,9,10-decahydroacridin-1,8-dion as acid base titration indicator
Abstract
The aim of this work is the synthesis of new 10-hydroxydecahydroacridine-1,8-dione derivative, determination of the structure and to study the possibility of using this compound as an indicator of acid-base titration. Environmentally friendly synthesis of 10-hydroxy-3,3,6,6-tetramethyl-9-(4-hydroxy-3-methoxyphe-nyl)-1,2,3,4,5,6,7,8,9,10-decahydroacridin-1,8-dion has been developed by one pot interaction of dimedone, hydroxylamine and 4-hydroxy-3-methoxybenzoic aldehyde in water-alcohol or water solution using citric acid or sodium dodecyl sulfate as catalysts, respectively. Purification of the synthesized compound was carried out by crystallization from ethanol. The obtained compound was characterised by 1H NMR ,13C NMR and UV-Vis spectroscopies. This substance in water-alcohol solution shows intense violet light absorption. Addition alkali induces red shift of absorption maximum to the blue region. UV irradiation of solution of this substance in alcohol induces two-band fluorescence in the visible region. One band disappears upon addition of a base in solution. The structure of the obtained compound was confirmed by high resolution massspectrometry analysis. In the mass-spectrum of 10-hydroxy-3,3,6,6-tetramethyl-9-(4-hydroxy-3-methoxyphe-nyl)-1,2,3,4,5,6,7,8,9,10-decahydroacridin-1,8-dion observed [M+1]+ ion peak. The base peak corresponds to tricyclic fragment due to the elimination aromatic cycle from molecular ion. This substance is colorless in acidic and neutral and pink in base solutions. The acid dissociation constant of this compound in a water-alcohol solution was determined by the UV-Vis spectroscopic technique. It was shown that the obtained compound can be used as an indicator for the titration of strong acids and bases.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):556-563
556-563
Physico-chemical biology
Increasing the biodegradability of epoxy materials by means of vegetable oils and their oxygenated derivatives
Abstract
Recycling of epoxy resin products is an urgent problem due to the microbiological resistance of such polymers. In this work, we aimed to increase the biodegradability of epoxy materials under the action of soil microorganisms and mycelial fungi. The modification of epoxy materials was carried out using soybean oil, rubber tree oil and their oxygenated derivatives, as well as a mixture of soybean oil and oleic acid. According to the obtained results, the introduction of a material based on unmodified epoxy resin into a soil leads to a 2.2-fold decrease in the respiratory activity of the soil microbiocenosis compared to untreated soil samples. This proves that epoxy-diane resins or hardeners (aminophenol) inhibit soil microbiocenosis. In comparison with the action of unmodified epoxy resins, the epoxy resins treated with vegetable oils and their oxygenated derivatives caused an increase in the respiratory activity of soil microbiocenosis, thus indicating the biodegradability of the materials under study. The decrease in the content of carboxylic acids in the composition of rubber tree oil after its epoxidation, which was confirmed by a decrease in the acid value, led to a slight decrease in the respiratory activity of soil microbiocenosis. For the same reason, the carbonation of vegetable oils had a similar effect. An improved biodegradation profile of epoxy materials following their modification was also confirmed by assessing their fungal resistance in terms of the number of the Tricho-derma fungi. It was concluded that vegetable oils and their oxygenated derivatives increase the biodegradability of epoxy materials. Among all the studied compositions, the epoxy materials modified with rubber tree oil and a mixture of soybean oil and oleic acid demonstrated the highest level of biodegradability.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):700-707
700-707
Biosynthesis of exopolysaccharides by soil bacteria Paenibacillus mucilaginosus on a nutrient molasses medium
Abstract
Bacterial exopolysaccharides exhibiting water-retaining and cementing properties play an essential role in such processes as the formation and stabilization of soil aggregates, regulation of nutrients and water flow through plant roots, as well as reduction of salt stress in plants. When bacteria producing exopolysaccharides are introduced into a soil, plants become more resistant to water stress due to improved structure and significant accumulation of proline, sugars and free amino acids under the conditions of water deficiency. In this work, we set out to determine the efficiency of exopolysaccharide biosynthesis by the soil bacteria Paenibacillus mucilaginosus when cultivated on a nutrient molasses medium. The bacterial strains P. mucilaginosus 560 and 574 provided by the Departmental collection of non-pathogenic microorganisms for agricultural purposes (All-Russia Research Institute for Agricultural Microbiology, St. Petersburg) were used as exopolysaccharide producers. In order to determine the influence of cultivation conditions on the synthesis of exopolysaccharides by P. mucilaginosus, the one-factor-at-a-time (OFAT) method was used. On the basis of the obtained results, we determined the most effective producer of exopolysaccharides, the age and dose of the inoculum, the optimal values of the cultivation temperature and medium pH, the source of nitrogen and its concentration, as well as the aeration conditions affecting exopolysaccharide biosynthesis and the growth of the selected bacterial strain P. mucilaginosus. It was established that the P. mucilaginosus 574 strain is the most effective producer of exopolysaccharides. It was shown that the biosynthesis of exopolysaccharides is most effective and economical upon the cultivation of P. mucilaginosus 574 on a nutrient medium containing 2% molasses without addition of minerals and nitrogen. The maximum amount of exopolysaccharides can reach 9.55 g/L on a nutrient medium containing 2% molasses at a volume of 50 ml with the addition of 0.1% corn extract as an inducer of exopolysaccharide synthesis at a cultivation temperature of 30±1 °C, a medium pH of 6.0±0.2 with the introduction of 5% inoculum after 24 hours of inoculation. The obtained research results are recommended for use when creating new technologies for the production of microbiological fertilizers.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):708-718
708-718
Growth-inhibiting effect of azoxystrobin and its ability to inhibit sugar consumption in winter wheat sprouts and roots
Abstract
This study aimed to assess the prospects for the use of azoxystrobin, a fungicide of the strobilurin class, for increasing the resistance of winter wheat to low temperatures. The effect of azoxystrobin on growth processes, cell viability and the content of water-soluble carbohydrates in winter wheat (Triticum aestivum L.), the Ikutskaya variety, was studied. In comparison with other synthetic strobilurins, azoxystrobin is more frequently used in multicomponent fungicidal preparations. Azoxystrobin is a broad-spectrum fungicide that inhibits complex III of the mitochondrial electron transport chain. Experiments were carried out in laboratory conditions using 3-day-old etiolated winter wheat sprouts. The sprouts were grown in a dark place at a temperature of +24 °C on azoxystrobin solutions dissolved in a 0.36% aqueous solution of dimethyl sulfoxide, distilled water and a 0.36% dimethyl sulfoxide solution. The effect of various azoxystrobin concentrations (2.5, 5, 10 and 20 μM) on the growth of sprouts and roots was assessed, along with the viability of sprout and root cells. Azoxystrobin had a concentration-dependent growth-inhibiting effect on sprouts and roots. At concentrations of 2.5 μM and 20 μM, the inhibition degree for sprouts varied from 2.8% to 41.7%, respectively. For roots, these values comprised 34.6 and 63.1%, respectively. The growth-inhibiting effect was not accompanied by a decrease in the cell viability of sprouts and roots, which was assessed using in vivo staining with fluorescein diacetate (FDA). The effect of azoxystrobin at a concentration of 10 μM on the sugar content in germinated sprouts was also evaluated. At this concentration of azoxystrobin, the sugar content was higher by 3.6% in sprouts germinated on a dimethyl sulfoxide solution. Since growth inhibition and sugar accumulation are important factors in plant adaptation to low temperatures, further research into effects of azoxystrobin on the physiological and biochemical parameters of plants associated with the development of low-temperature resistance seems justified.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):657-665
657-665
Study of physicochemical changes and microbiological parameters of semi-finished potato products after electron-beam sterilization
Abstract
A popular method for electron-beam sterilization of agricultural products consists in their exposure to ionizing radiation, also called beta-radiation. Beta-radiation contributes to the preservation of the quality and safety of freshly harvested crops and can be used to disinfect semi-finished products. In this work, we aimed to study the effect of various doses of ionizing radiation (1, 3, 6 and 9 kGy) on vacuumized peeled and cut potatoes of the Bellarosa variety. Potato samples were treated with ascorbic acid at concentrations of 3, 6 and 9% in order to preserve the native content of vitamin C and the initial structural and mechanical properties. PET packages were used for evacuation, since this material emits no hazardous or harmful impurities in such aggressive environments as 9% ascorbic acid solution and 9 kGy radiation. Studies of organoleptic, physicochemical and microbiological parameters of semi-finished potato products were carried out using conventional methods. According to the obtained results, an irradiation dose of 1 kGy neither affects significantly the quality of a semi-finished potato product, nor contributes to a decrease in the number of pathogens. An irradiation dose of 3 kGy has no significant effect on the controlled parameters, although a decrease in the number of pathogens is observed. An irradiation dose of 6 kGy has a significant effect on the microbiological indicators; however, at low concentrations of ascorbic acid (3 and 6%), the organoleptic indicators of the studied semi-finished products begin to deteriorate. At a dose of 9 kGy, almost all microorganisms die, and the controlled parameters deteriorate regardless of the ascorbic acid concentration. It is concluded that the optimal irradiation doses for semi-finished potato products comprise 3 and 6 kGy. The optimal concentration of ascorbic acid was found to be 9%, at which the quality and safety indicators of semifinished potato products are preserved for 7 days of storage.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):666-677
666-677
Thermal destruction of d -mannose condensation products using p -aminoacetanilide in solvent-free systems
Abstract
Thermal destruction of D-mannose condensation products using p-aminoacetanilide in solvent-free systems, such as paraffinic oil and a KBr-matrix, was studied by the methods of electronic and vibrational spectroscopy. The thermal destruction of mannosylamine in a KBr matrix is accompanied by intense coloration. At the same time, the bands in the IR spectra characterizing the functionalization of aminoacetanilide retain their position and intensity, which indicates the absence of transformation of the amine fragment. The appearance of the 1645, 1680, 1690 cm-1 bands of enone O=C-C=C- fragments is noted, along with the 1750 and 1780 cm-1 bands attributed to the stretching C=O vibrations of esters and lactones likely formed as a result of transformation of the primary mannosylamine degradation products. The thermal destruction of a mannosylamine suspension in paraffinic oil shows a lower transformation of the mannosyla-mine structure in comparison with experimental processes in a KBr matrix. The spectra depict the bands of С = O vibrations in different structural environments, as well as the signal shift of 1280 cm-1 into the low- frequency region characterizing the elimination of arylamine. The reflection spectra of the alcohol solutions of destruction products demonstrate the presence of only the 1750 cm-1 band; the 1780 cm-1 band does not appear probably due to the instability of lactones in solutions, which causes their recyclization. An analysis of vibrational spectra showed the absence of bands characteristic of melanoidin N-heterocycles due to the predominant formation of acyclic conjugated systems and carboxylic acid derivatives in the studied solvent-free systems. In the electronic spectra of the alcohol solutions of destruction products in both systems, maxima of about 260 nm were recorded. These maxima correspond to the absorption of oxyenone chromophores and the continuous absorption region in the visible part of the spectrum, caused by the formation of extended chromophores, i.e. condensation products of the intermediates of mannosylamine decomposition. The obtained results can be useful both when selecting conditions for the Maillard reaction with a given functionalization and when developing methods for the synthesis of antioxidant agents for protecting polymers and oils.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):581-589
581-589
Use of an electrochemical biotesting technique for comparing the antibiotic properties of plant extracts obtained using liquefied CO2
Abstract
We present a biotesting technique that allows periodic (every 2 hours) recording of changes in the pH, redox potential and electrical conductivity of a liquid nutrient medium incubated in the presence or absence of viable test microorganisms and test samples. This technique was used to compare the pro- and antibiotic activity of various concentrations of subcritical whole extracts obtained from 10 plant species using liquefied CO2 against Lactobacillus acidophilus and other test microorganisms, such as Chlorella vulgaris and Rhodotorula glutinis. It was established that the proposed technique provides for a quicker, more objective and informative, as well as less material-consuming and labour-intensive, microbiological testing compared to conventional visual methods aimed at assessing effects of pharmaceutical, food and other products on the activity of test microorganisms. Among the studied plant varieties, extracts from celandine roots (Chelidonium majus) and calendula officinalis flowers (Calendula officinalis) at a concentration of 3% vol. and above demonstrated the most active prolonged antibiotic properties. Extracts from mistletoe shoots (Viscum album) and walnut leaves (Juglans regia) at a concentration of 0.2% vol. showed the most active prolonged probiotic properties. The initial pro- and antibiotic activity of the tested extracts was in most cases greater than their prolonged activity. At the same time, the medium-term (with respect to the period of interaction of the extracts and microorganisms) pro- and antibiotic activity of the tested extracts showed intermediate values between their initial and prolonged activity. It is noteworthy that a decrease in the concentration of the tested extracts in the test environment led to a steady decrease in their antibiotic activity, at the same time as increasing their probiotic activity. Thus, it is clear that the pro- and antibiotic activity of pharmaceutical, food and other products, including various plant extracts, is determined not only by the choice of raw materials and the method for extracting biologically active substances, but also by the concentration of extracts, the time of their interaction with microbiota and other living organisms, as well as by a variety of other factors. The exact nature of these dependencies can only be established through multiple tests, which can conveniently be carried out using the methodology presented in this work.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):590-602
590-602
Sorption action of silicon-containing samples against bacteria
Abstract
Silicon-containing amorphous substances, such as silicon dioxide (silica) and aluminosilicates, have a wide range of applications due to their porosity, chemical inertness and thermal stability. These materials are conventionally produced from quartz, diatomite and silicates of various compositions. However, the existing methods for isolating pure compounds are quite expensive and energy intensive. Renewable biological waste containing large amounts of silicon, e.g. rice husks and straw (Oryza sativa), can be used as an alternative raw material. The main advantages of such a material consist in its low cost, almost constant chemical composition, as well as simple and relatively inexpensive processing methods. Due to the high content of silicon dioxide in rice husks and straw, their recycling products are effective adsorbents of many types of pollutants from aqueous solutions. Although some publications describe interaction processes between microorganisms and highly-dispersive synthetic materials based on silicon dioxide of mineral origin, there is a lack of information on the biogenic forms of silica and aluminosilicates obtained from rice production wastes. In previous studies, we established the ability of a number of silicon-containing samples isolated from rice production wastes, depending on the raw material (husk or straw) and production conditions, to bind different bacteria, e.g. Escherichia coli, Streptococcus aureus, Candida albicans, Pseudomonas aeruginosa and Bacillus subtilis. In this work, we studied the sorption action of amorphous silicon dioxide and aluminosilicates obtained from rice husks and straw against the test cultures of Escherichia coli and Bacillus subtilis. The reference materials were such commercial products as expanded vermiculite (natural aluminosilicate) and the ‘White Coal’ sorbent containing approximately equal proportions of silica and microcrystalline cellulose. The obtained results were discussed in the context of the physicochemical parameters of the studied substances, including their chemical composition, IR absorption spectra, characteristics of the acid-base properties of the surface assessed by the methods of pH-metry and adsorption of acid-base indicators (Hammett's method). It was established that the sorption capacity of a sorbent in relation to bacteria depends on the initial material, its composition and production method.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):603-612
603-612
Study of potential anti-carcinogenic and antioxidant effects of plant extracts
Abstract
One of the main etiological factors in the development of some malignant tumours is the presence of chronic inflammatory processes. A number of biomedical studies have confirmed the anticarcinogenic effect of anti-inflammatory drugs with respect to colon cancers. In addition, some biologically active substances present in medicinal plants have been found to exhibit both anti-carcinogenic and antioxidant activity. In this paper, we investigate potential anticarcinogenic effects of extracts obtained from plant raw materials, including lingonberry (Vaccinium vttis-idaea), raspberry (Rubus idaeus), black chokeberry (Aronia melanocarpa), grape seeds (Vitis L.), grape pomace (Vitis L.), Krasnodar green tea (Camellia sinensis), ginseng (Panax L.), fireweed (Chamaenerion angustifolium) and coffee (Coffea arabica). The effect of these extracts on the growth and viability of colon HCT-116 cancer cells was assessed in vitro using the method of MTT assay. In addition, the effect of non-toxic doses of the extracts under study on the basal and induced levels of pro-inflammatory gene expression - cyclooxygenase (COX2), inducible NO synthase (iNOS) and interleukin 8 (IL8) - was assessed by quantitative PCR. The working concentrations of the extracts under study for HCT-116 cells were determined. It is demonstrated that all investigated extracts are capable of suppressing the expression of COX-2, iNOS and IL-8. Black chokeberry and fireweed extracts exhibit the most pronounced total inhibitory effect on the expression of these inflammatory genes. Future research should investigate effects of black chokeberry and fireweed extracts on the induced expression of COX-2, iNOS and IL-8 and their anti-carcinogenic activity in vivo. The antioxidant activity determined using DPPH and FRAP was the highest for black chokeberry, raspberry and fireweed. A relationship between the anticar-cinogenic and antioxidant effects of the extracts under study was revealed.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):613-626
613-626
Sugar-mediated regulation and the role of HXK1, SnRK1, TOR kinases in Arabidopsis thaliana
Abstract
Sugars play an important role in plant metabolism. They are not only a source of energy, but also an integral part of the intracellular signalling network. Signals involving sugars regulate a variety of metabolic reactions, e.g. carbon and nitrogen metabolism, and produce plant response to biotic and abiotic stresses. This paper provides a brief review of modern publications about sugars acting as metabolites and signaling molecules. The well-known and recently discovered pathways for the transmission of sugar-mediated signals are described, along with their role in the regulation of plant metabolism and expression of nuclear genes. Hexokinase 1 (an enzyme for glucose synthesis), which was one of the first studied participants in the sugar-mediated signalling network, regulates the expression of many nuclear genes in response to changes in the glucose level. Hexokinase 1 should be considered as a broad-spectrum regulator due to its participation in the transmission of mitochondrial-nuclear signals and regulation of aging processes in plants, which functions lay beyond the regulation of metabolic reactions. Of particular interest is the participation of sugar-mediated signals in the switching of metabolic reactions in response to changes in carbohydrate concentrations. Sugar deficiency deactivates most energy-intensive processes, at the same time as stimulating photosynthesis or (in its absence) enhancing catabolic reactions due to activation of the SnRK1 kinase. Under sufficient sugar levels, the SnRK1 kinase is suppressed and the TOR kinase is activated, which stimulates anabolic reactions and growth. The role of competing SnRK1 and TOR kinases as the main regulators of such a process is considered, along with the function of signals mediated by trehalose-6-phosphate highly similar to the TOR signalling pathway. All these regulatory mechanisms enable plants to adapt to environmental changes and maintain homeostasis. It is possible that additional information will be obtained in the nearest future on the interaction of energy and stress-dependent signals in plants through the antagonism of TOR and SnRK1.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):627-638
627-638
Identification of a compound similar to triiodothyronine in the cells of higher plants
Abstract
Iodothyronines play an important role in human and animal metabolism; however, their action in plant species is yet to be described. The known beneficial effects of medicinal plants on the function of the thyroid gland suggest the presence of compounds similar to thyroid hormones in plant cells. In this work, we aim to reveal the presence of 3,5,3'-triiodothyronine, the most active representative of iodothyronines, in the cells of higher plants. Using the method of immunoenzyme analysis, it was determined that the roots and stems of bean seedlings contain a compound interacting with a polyclonal serum to 3,5,3'-triiodothyronine. The identified compound is distributed unevenly within the cell: its concentration in the cell nuclei is 7-10 times higher than that in the cytoplasm. Along with bean plants, 8 randomly selected plants belonging to both dicotyledonous and monocotyledonous families were studied. In all the studied species, the presence of an analogue of 3,5,3'-triiodothyronine was determined using the method of immunoenzyme analysis. The use of exogenous iodothyronine - thyroxine (3,5,3',5'-tetraiodothyronine) - for the pre-sowing treatment of wheat seeds reliably improved their germination and led to a significant increase in the root-shoot mass ratio of five-day-old wheat seedlings under the soaking time of 6 and 12 hours. The treatment of wheat seeds with thyroxine led to a significant decrease in the concentration of the identified compound in the stem and root cell nuclei of five-day-old wheat seedlings. The revealed physiological and accumulation effects of exogeus 3,5,3',5' tetraiodothyronine suggest its involvement in gene regulation in the cells of higher plants, similarly to that in animal cells.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):639-646
639-646
Effects of Bacillus thuringiensis 0271 on individual indicators of nonspecific resistance of Origanum vulgare L. to stressful conditions
Abstract
In this paper, we aim to study the effect of the Bacillus thuriengiensis strain var. darmstadiensis 0271 on the biochemical parameters of Origanum vulgare L., which determine its nonspecific resistance to unfavourable environmental conditions. The research materials were a liquid spore culture of B. Thuringiensis 0271 and the following oregano samples: 100.1 with 75.5% of carvacrol, g-4with 52.0% of carvacrol, No. 2 with 59.85% of а-terpineol, No. 1 with 21.5% of germacrene D and 19.4% of в-caryophyllene. The preservation of the strain spores on the leaf surface of Origanum vulgare was determined using A.G. Kolchevskys method. The proline content was determined by V.A. Khramov’s and E.M. Ageeva’s method, while the pigment content was measured spectrophotometrically. The total content of phenolic compounds, ascorbic acid and water-soluble carbohydrates was established according to the methods by M.N. Zaprometov, M.M. Okuntsov and M. Dubois, respectively. Ten days after treating the leaves of the 100.1 and No. 1 oregano varieties with the spore culture of B. Thuringiensis 0271, the amount of chlorophylls decreased by 27.1 and 15.2% compared to the control, respectively. At the same time, the amount of chlorophylls increased by 91.4 and 72.7% in the leaves of the g-4and No. 2 varieties, respectively. On the 10th day of the experiment, the amount of proline and phenolic compounds decreased by 4 times in the leaves of the g-4 sample. Compared to the control, the 100.1 variety demonstrated a decrease in the amount of soluble carbohydrates and phenolic compounds by 1.76 and 2.0 times, respectively. On the 10th day of the experiment, the treatment of O. vulgare plants with B. Thuringiensis 0271 promoted the accumulation of antioxidants in the leaves of the g-4sample by 14.5% compared to the control.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):647-656
647-656
Fourier-transform infrared spectroscopy in a comparative study of animal and plant proteins
Abstract
The method of infrared attenuated total reflection spectroscopy was used to compare proteins (sarcoplasmic, myofibrillar, stroma) contained in the pork muscle tissue, globular proteins obtained from industrially crushed flax seeds, as well as protein-polysaccharide complexes extracted from husked seed coats and whole seeds. Protein components were isolated from saline solutions by precipitation with a threefold excess of 96% ethanol and 5% trichloroacetic acid, as well as by isoelectric precipitation at pH = 4.2. It is shown that the use of different anatomical parts (core and seed coat), including crushed or whole forms and flax seed meal, under varying conditions of pre-treatment, extraction and isolation allow biologically active protein-containing products to be obtained. Such products - protein concentrates, peptide polysaccharides and protein-lipid-polysaccharide complexes with a variable composition and ratio of components - are valuable raw materials for the food industry, medicine, pharmacopoeia and cosmetology. A comparative study of the kinetics of air drying of crude plant and animal globular proteins at 20°C showed these proteins to be similar in terms of extreme changes in the spectra of light absorption curves and the intensity of the main characteristic bands upon moisture removal. Temperature changes, affecting the general appearance of light absorption spectra, lead to deformation of the Amide-I band, which carries information about the protein structure. Deformational changes may be promoted not only by differentiation of globular proteins (albumins and globulins), but also by packing of their polypeptide chains during reconstruction or formation of a new secondary structure destroyed as a result of various mechanical and chemical interventions. According to the obtained data, elevated temperatures have a significant effect on the structural transformations of both protein concentrates and protein-polysaccharide complexes, regardless of their nature.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):678-690
678-690
Some regularities in the process of anthocyanin extraction from vegetable sources
Abstract
This work investigates regularities in the process of extracting anthocyanins from various plant sources in the medium of extractants. For extraction, fresh plant samples were used, including the roots of purple carrots, roots of purple potatoes of the Amethyst variety, fresh fruits of Michurin's aronia, fruits of the garden nightshade, cornelian cherries, blueberries and red cabbage, as well as dried peony petals. The extraction was carried out by infusing the plant material under study in a selected extractant (left overnight). The concentration of anthocyanins was determined spectrophotometrically. It was shown that a 0.1 M aqueous solution of HCl is an effective and environmentally friendly extractant allowing for the extraction of anthocyanins from various sources. Provided that the medium acidity is greater than 1, significant losses of anthocyanins are possible: 5-45% at pH = 2; 33-88% at pH = 3; 41-92% when extracted with distilled water. Acylation does not contribute to an increase in the degree of anthocyanin extraction. The addition of organic solvents (ethanol, acetonitrile and glycerin) can significantly accelerate the anthocyanin extraction in some cases, which is particularly true for cornelian cherries. When using crushed material, the influence of the extractant on the degree of extraction is minimal. Information is presented on the solvatochromic effect, which affects the spectral characteristics of some anthocyanin solutions. It was shown that the shift of the absorption band maximum is the greatest for non-acylated anthocyanins, while decreasing for acylated compounds. The latter is most likely to be associated with the intramolecular copigmentation of acylated anthocyanins in aqueous solutions. When determining the concentration of anthocyanins in solvents with different concentrations of organic additives, the solvatochromic effect should be taken into account. The addition of an organic solvent leads not only to a shift in the absorption band maxima, but also to significant hyperchromic effects. If this effect is ignored, errors in determination of anthocyanins can exceed 70%. This paper proposes a simple and effective approach to considering these effects using a cross-dilution scheme. Therefore, the choice of extractants for efficient anthocyanin extraction from various plant raw materials was experimentally substantiated, and a method for evaluating solvatochromic effects was proposed.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):691-699
691-699
Effects of crude oil on the biological activity of chernozem soils
Abstract
The article investigates the effect of crude oil on soil microorganisms and the enzymatic activity of chernozem soils. Experiments were carried out on podzolized medium loamy chernozem in the Samara region using high-sulphur crude oil of medium density. Per 1 kg of soil, 10.00 g (1%), 30.00 g (3%) and 50.00 g (5%) of oil were applied. According to the obtained results, the native soil microbiota contains a wide variety of microorganisms capable of oxidizing both individual hydrocarbons and crude oil in general. Bacteria of the Acinetobacter, Bacillus, Mycobacterium, Pseudomonas and Streptomyces genera, filamentous fungi of the Aspergillus and Penicillium genera, as well as Candida yeast showed the greatest activity in the degradation of both individual hydrocarbons and crude oil in general. The soils freshly polluted with oil demonstrated an increase in the number of bacteria that consume organic forms of nitrogen, actinomycetes, fungi and hydro-carbon-oxidizing microorganisms. In addition, a growing trend in the number of autochthonous microorganisms participating in the mineralization of humic substances was observed. Following 3 months of experiments, a decrease in the number of bacteria consuming organic forms of nitrogen and actinomycetes was revealed. The number of fungi showed the most pronounced decrease upon addition of 3 and 5% of oil, while the number of autochthonous microorganisms participating in the mineralization of humic substances and hydrocarbon-oxidizing microorganisms grew with an increase in the degree of oil pollution. Inhibition of various microorganisms by means of physical or toxic action of hydrocarbons contained in crude oil can cause a decrease in the activity of enzymes present in chernozem soils. Oil hydrocarbons inhibit the activity of polyphenol oxidase, catalase, invertase, phosphatase and lipase present in chernozem soils, although slightly stimulating the peroxidase activity. A decrease in the soil humification coefficient indicates that the oxidation of humic substances prevail over the decomposition of organic aromatic compounds into soil humus components, as well as a decrease in soil fertility as a result of its contamination with crude oil hydrocarbons.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):719-727
719-727
Molecular weight characteristics and sorption properties of pectin extracted from different substrates
Abstract
The study of natural polymers is one of the most advanced tasks of modern chemistry. One of these polymers is the common polysaccharide pectin. Widespread acid hydrolysis was used to extract pectin from various substrates. Oxalic, citric and hydrochloric acids have been investigated for this purpose. The water-soluble pectin-containing fraction was extracted from the apples, sugar beet, lemon peel, pine needles. The optimal condition is heating the substrate in a boiling water bath for 1 hour with reflux in a solution of hydrochloric acid (pH 2-3). We neutralized the extract after cooling with an ammonia solution to isolate the dry powder of the pectin-containing component and the pectin was precipitated with ethanol. The study of pectin solutions by the method of gel permeation chromatography showed that they most often have three polymer fractions that are close in molecular weights: ~17-20, ~10-12 and ~0.5 kDa. The content of the last fraction in all selected samples is predominant. Solutions of pre-planted powders of the pectin-containing fraction significantly differ from the previously discussed results: the oligomeric fraction is practically absent in them. For a number of samples of pectin powders, the degree of esterification was determined by potentiometric titration. The dependence of the degree of esterification on both the feedstock and the isolation method was revealed. The method of reverse complexometric titration was used to study the sorption capacity of pectin. The analysis results suggest that there is an inversely proportional dependence of the degree of lead sorption of the pectin sample on its degree of esterification.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2020;10(4):728-737
728-737