Vol. 54 No. 1 (251) (2020)

The method has been developed for the preparation of ethyl esters of triazolo-substituted thioglycolic acid, basis on which the corresponding hydrazides, thiosemicarbazides and 1,2,4-triazolo-1,2,4-triazoles were synthesized by successive transformations. By the data of ¹H and ¹³C NMR spectroscopy and elemental analysis have been established the structures of obtained compounds. Biological studies have shown that triazolo-triazoles at concentrations of 50 and 100 μm/mL reduce the viability of nematodes Steinernema Feltiae by 10–40%.

ring were successfully synthesized based on thiosemicarbazones of 3-acetyl-2-oxo-2,5-dihydrofurans. The synthesized compounds exhibited moderate to defined antibacterial activities against Gram-positive (Staphylococcus aureus 209P and 1) and Gram-negative (Shigella Flexneri 6858, Esherichia coli 0–55) bacteria compared to furazolidone.

A comparative study of the esterification reactions of erythritol, mannitol, sorbitol, xylitol, citric and tartaric acids with higher aliphatic acids and alcohols without catalysts and under conditions for acid catalysis at temperatures of 150–200ºC has been carried out. Optimum temperatures and conditions for the expediency of using solvents and acid catalysts to increase the yields of esters were determined.

The turbidimetric and Z-potentiometric methods were used for the assessment of some properties of diatomite – bentonite based conditioners for dewatering of effluents from the digestate of a biogas plant. These physical conditioners were prepared based on natural porous highly dispersible systems such as bentonite and diatomaceous earth. Three types of modified systems in the forms of CaO were used, which differ from each other in the ratio of the content of bentonite and diatomite. The role of the silica-containing component is to ensure the structuring of these systems. Diatomite was used for this purpose.

The main results obtained in the study of the possibility of low-temperature chemical modification of porous silica, applying various nanodispersed substances to their surface are given. It has been shown that the use of the chemical transport reaction (CTR) H₂O₂/ZnO for this purpose with the participation of H₂O₂ vapors at room temperature makes it possible to apply a number of oxides, sulfides and metal halides to the surface of various sorbents. An important advantage of the proposed modification method is that changes in the original texture parameters of the substrate are minimized. Using the example of modifying the behavior of highly pure SiO₂ with zinc oxide, it was shown that the decomposition of gaseous intermediate products of CTR H₂O₂/ZnO occurs mainly in pores with a diameter of more than 6 nm.

The paper presents the results of studies on the interaction of intercalators ethidium bromide (EtBr) and methylene blue (MB) with synthetic double-stranded (ds) ribonucleotide ds-poly(rA)-poly(rU) at a solution ionic strengths of 0.02, 0.04 and 0.1 M. These results revealed that poly(rA)-poly(rU) has a relatively unstable structure at the ionic strengths μ$\leq$0.02 M, which leads to the interaction of the mentioned ligands with this polynucleotide. EtBr affinity for ds-poly(rA)-poly(rU) was revealed not to depend on the ionic strength of the solution, while the affinity of MB for this polynucleotide depends on this factor, as well as on the structural state of the polynucleotide.

The aim of the present study was to determine the effect of the Indian mycorrhizal preparation Mykonet (Mn) of Endo type on agronomical and economic indicators of the hot and sweet pepper production. The study was conducted with two sweet (Zmrukht and Nush-55) and two hot varieties of pepper (Kon and Punj). The experiments were carried out according to the block randomization method. It has been shown that Mn improves the biological and economic characteristics of sweet and hot peppers, depending on the treatment duration and variety. The most effective was 2 h treatment. The dry matter content was increased slightly, but increased for sugars and ascorbic acid. The best effect was obtained for Zmrukht. Given that Mn has improved the agronomical and economic characteristics of sweet and hot peppers, it can be recommended for pepper production.

In this study anaerobic utilization of mixed carbon sources (glucose, glycerol, formate) and generation of fermentation end-products by Escherichia coli at slightly alkaline and slightly acidic pHs was investigated at the first time. It has been shown that E. coli is able to perform co-fermentation of glucose and glycerol in the presence of external formate. The latter was utilized by bacterial cells at first. Acetate is the permanent product (25–50 mM) during both glucose and glycerol utilization. It has been revealed that composition of fermentation end-products depends not only on external pH, but also on co-utilization of substrates.

The endosymbiotic hypothesis suggests that mitochondria were free-living organisms that colonized another cells, and millions of years of co-evolution resulted in the transfer of a large number of genes from mitochondria to the nucleus. Recent studies indicate that this is an ongoing process and can be due to the impact of cells to DNA damaging agents, e.g. radiation or chemical mutagens. Here we demonstrate that cytogenetically visible mitochondrial DNA translocation into interphase nuclei genome in human blood lymphocytes can be identified via fluorescence in situ hybridization after exposure of cells to doxorubicin.

As with any essential oil (EO), the content and composition of Rosa × damascena Mill L. (EO) can be changed significantly, depending on the cultivation methods and terroir. The purpose of this research is to determine the chemical composition and biological activities of EO distilled from Damask rose flowers cultivated in Armenia at high elevation. The EO was obtained by hydro-distillation method, the chemical composition was analyzed by gas-chromatography analysis. The EO main compounds were citronellol (38.04%), nonadecane (4.9 %), nerol (7.12%), geraniol (26.32%) and linalool (6.15%). The antioxidant activity of EO was measured by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), TBARS and metal-chelating activity determination assays. Antimicrobial activity was determined by agar-diffusion method. According to our investigations the minimal inhibitory concentration values against tested gram-positive and gram-negative bacteria were varied between the 2.5 and 20 mg·mL^–1. Obtained data revealed high (DPPH) scavenging, metal chelating, lipid peroxidation inhibiting activities of EO. Thus, the results revealed a good potential of R. damascena EO.

Soil salinization, caused by natural and anthropogenic factors, is a pressing environmental issue in Masis Region, which is one of the important regions of irrigated agriculture in Armenia. To prevent this adverse process the groundwater quality in the region has been evaluated for agricultural uses. For this purpose, the water samples were collected from 27 extraction wells and analyzed for major quality parameters following standard test procedures. Other chemical indices, notably sodium adsorption ratio, permeability index and magnesium hazard, were derived from the measured quality parameters. During the studies the areas with good, permissible and unsuitable groundwater quality for irrigation were determined. According to results obtained for irrigation of agricultural lands in Masis Region (especially in its eastern and southern parts), the usage of highly saline groundwater from shallow horizons should be restricted as much as possible, and in Ranchpar Village, where the groundwater even from the high depths has а high salinity, it is required to use an alternative source of irrigation water.

The reaction between urea and melamine was studied. The reaction resulted in tris-carbamide derivative of melamine. During the reaction between the melamine derivative and the glycoside group of chitosan the sim-triazine functional groups were formed, which are included in the structure of synthesized derivative of chitosan. The synthesized derivative of chitosan was tested. It is recommended to use this chitosan derivative as an absorbent for the separation of heavy metal ions such as Cd²⁺, Hg¹⁺, Hg²⁺, Co²⁺, Ag¹⁺, As³⁺, As⁵⁺, etc. from the aqueous solutions of salts.

The nocturnal vertical migration activity of amphipods in the two coastal areas of Lake Baikal, exposed and not exposed to the influence of artificial lighting was investigated. In the conditions of prolonged artificial lighting, the migration activity of amphipods reduced on average by 20 times. Statistical analysis demonstrated significant differences between the two places of video surveillance indicating about the significant impact of light pollution on the nocturnal migration of the benthic animals.