Vol. 53 No. 3 (250) (2019)

A method for obtaining methyl esters of β-1,2,4-triazole-substituted alanines by condensation of methyl acrylate with 3,4-disubstituted 5-mercapto-1,2,4-triazoles has been developed. Based on the products obtained, a number of new biheterocyclic systems, previously not described in the literature, have been synthesized. By testing the obtained compounds it was established that individual representatives of the latter exhibited antinematode activity for agricultural nematodes Steinernema feltiae, increasing the viability of the latter by 3–5%.

New 2-N-substituted 2,5-dihydrofurans were successfully synthesized by the convenient and efficient method, which was based on the reaction of functionalized 2-imino-2,5-dihydrofurans with benzohydrazide in glacial acetic acid. Synthesized compounds exhibited moderate to defined antibacterial activities against Grampositive (Staphylococcus aureus – 209p and 1) and Gram-negative (Shigella Flexneri 6858, Esherichia coli 0–55) bacteria compared to furazolidone.

N-deacetylation of the amide groups of 4,4'-diamino-N-acetyldiphenylamine, 4,4'-di(p-acetaminoanilino)-N-acetyldiphenylamine and 4,4'-dinitro-N-acetyldiphenylamine were carried out. Reactions were proceeded under reflux, correspondingly by 4N alkaline mixture of methanol / dioxane and concentrated hydrochloric acid. The structures of obtained compounds were confirmed by NMR spectroscopy.

The complex formation of the copper(II) ion with salicylic acid by means of the EPR and UV-Vis spectroscopy methods has been studied under standard conditions within pH 4.0–10.2 values. It has been shown that in the pH 4.0–5.5 acidic media the I type complex is formed, in which the Cu²⁺ ion is connected with two salicylic acid ligands H2Sal and two water molecules, when in the pH 7.5–10 alkaline media the type II complex is formed, in which the Cu²⁺ ion is connected only with two salicylic acid anions Sal²–. By means of the EPR and UV-Vis spectroscopy methods it has been also estimated that the ligand field of the type I complexes is strengthener than that of the type I complexes.

The results of studying the physicomechanical and sorption properties of bifunctional sorbents obtained by chemical and electrochemical oxidation of the surface of carbonizates of apricot kernel shells are presented. It was shown that sorbents based on carbonizates obtained by microwave carbonization of shells, in comparison with sorbents obtained in the traditional way, are characterized by a more uniform pore distribution and a larger specific surface area and adsorption capacity.

A comparative study on the interaction of classical intercalator ethidium bromide (EtBr) with different nucleic acids (NA) has been carried out. EtBr was revealed to preferentially bind to ds-NA belonging to A-family, rather than to B-family, because the stabilizing effect of this ligand decreases in the following order: ds-poly(rA)-poly(rU), ds-poly(dA)-poly(dT), ds-DNA.

The changes of cell size parameters of Gram-negative Pseudomonas aeruginosa GRP3 and Gram-positive Bacillus subtilis AK3 soil bacteria during 30 min irradiation with low 7.2 mGy dose of Cs¹³⁷ γ-rays with 2.56 μW·m⁻²·s⁻¹ intensity were investigated. The obtained results have shown that the first 15 min irradiation was very stressful, and bacterial size parameters in both cases were increased, but during the next 15 min irradiation the size parameters were decreased approaching their initial values. Therefore, even though only very high doses of gamma radiation could be lethal for these bacteria, they are also sensitive to low doses. The results obtained allow to develop a new method for monitoring the level of radioactive contamination, based on membranous alterations in soil bacteria.

The character of deviations of blood clotting indices in acute hypoxia was studied, as this testifies to the development of hypercoagulation and thrombotic status. Maximum changes are recorded after the 3-hour period exposure, which indicates the deeper impact of the factor within the timeframe. Tocopherol use is considered effective, which as a powerful antioxidant and antihypoxant helps to stabilize blood cells membranes to create favorable conditions for biological oxidation processes and regulation of coagulation parameters and clotting time.

The aim of the study was to assess the groundwater quality for agricultural irrigation in Masis Region, which is one of the traditional agricultural areas of Armenia. In order to evaluate the quality of groundwater in the study area, 27 groundwater samples were collected and analyzed to obtain various parameters such as electrical conductivity (EC), pH, as well as Na⁺, K⁺, Ca²⁺, Mg²⁺, HCO₃ ^–, CO₃^2– and Cl^– contents. The detected concentrations were interpreted and compared with different international irrigation standards. Study results led us to the conclusion that to control the process of soil salinization in the Masis Region (especially in the eastern and southern parts) the groundwater from great depths should be used for irrigation of agricultural areas, and an alternative source of irrigation water should be found in Ranchpar Village due to unsuitability of groundwater for these purposes.

Phytoplankton quantitative and qualitative parameters in “Yerevanyan Lich” Reservoir and the Hrazdan River were investigated in April and June–August 2015. The results of the study showed that algal bloom registered in “Yerevanyan Lich” Reservoir in summer 2015 created new environmental conditions which led to significant changes in reservoir’s phytoplankton dominant complex, affecting also phytoplankton composition in the Hrazdan River sites located downstream from the reservoir.

The current status of phytoplankton community in Lake Sevan (LS) was investigated. Water samples for phytoplankton and mineral phosphorus analyses were collected seasonally (spring–fall) in 2018. The results of the study showed that the unstabilized processes and nutrient pollution of the lake ecosystem led to bluegreen algae bloom in July. All of this caused ecological and toxicological risks to the lake ecosystem and the environment and may lead to further algal blooms in LS.