Vol. 49 No. 3 (238) (2015)

Heat induced denaturation of bovine serum albumin (BSA) in dimethylsulfoxide (DMSO) containing solutions in the presence of potassium iodide has been studied using UV/vis spectroscopy method. It has been shown that the thermal stability of protein depends on competitive interactions taking place in the solution. At low DMSO concentrations (5 vol. %) BSA is more stable than at higher concentrations (10–25 vol. %).

Influence of amino acids (L-glycine, L-alanine, L-phenylalanine, L-serine, L-aspartic acid, L-lysine and L-leucine) on the critical micelle concentration (cmc) and thermodynamic of micellization of nonionic surfactant hexadecyl poly[oxyethylene(25)] alcohol (C₁₆A₂₅) in aqueous solutions at different temperatures was studied. It was shown that with the increase of amino acids concentration cmc of C₁₆A₂₅ decreased, and with the increase of the temperature cmc of C₁₆A₂₅ increased.

In the paper the migration of copper in water–sediment system and the dependence between copper content and pH, and dissolved oxygen were investigated. The Hrazdan River was the study area, one of the largest and the most important rivers in Armenia. Samples were taken from 6 sampling points of the Hrazdan River basin (66 samples of water and bottom sediment) during 2012–2013. Results of copper content analysis reveal that none of the identified values exceed maximum permissible concentration. The correlation coefficients between copper content and, both for pH and dissolved oxygen, were obtained. The influence of pH and dissolved oxygen on migration of copper in water–bottom sediment system was identified.

On the example of the model reaction of cumene initiation oxidation on kinetic method, the antioxidant properties of ethyl acetate extracts of leaves and fruits of twelve different plants are investigated. Both the content of the antioxidant substances in the studied extracts and their antioxidant activity are defined. It is established that most of the studied extracts of antioxidants contained extracts of Evening Primrose leaves (2.93·10^–5 mol/L in 1 mg) and Scarlet amaranth (1.15·10^–5 mol/L). The highest antioxidant activity of the extracts from the leaves showed Coneflower (3.21·10⁵ L/mol·s), Pumpkin (2.93·105 L/mol·s), Goosefoot (2.70·10⁵ L/mol·s) and Grecian Silk Vine (2.58·10⁵ L/mol·s). It was shown that oxidation products (Q) of origin antioxidants in the extracts also possess antioxidant activities. Correlation was found between the pre-exponential factor (lgA) and energy activation (E) for the constant rate reaction RO$^{\small{\bullet}}_2$+InH$\longrightarrow^{\small{k_7}}$ ROOH +In$^{\small{\bullet}}$ and RO$^{\small{\bullet}}_2$+$Q\longrightarrow^{\small{k_{71}}}Q^{\small{\bullet}}$ + ROOH. For constant k₇ is established that lgA = 4.9 +0.64 E and for k₇₁ lgA = 2.6 +0.64 E.

Growth of filamentous fungi in grape processing products depends on physical, chemical and biological factors. Our researches revealed high contamination level of dried vine fruit samples by filamentous fungi at high values of water activity. Definite correlation between values of acidity (pH) and sporulation level of dried vine fruit by filamentous fungi is revealed as well. The effect of temperature conditions of storage on mycobiota and contamination level of Armenian dried vine fruit by microscopic filamentous fungi is also studied. Storage of dried vine fruit in temperature lower then 4°С conditions promotes reduction of its sporulation degree by filamentous fungi.

In this work the data of methylene blue (MB) and Hoechst 33258 interaction with DNA are presented. It has been shown that at 0.002 M ionic strength of solution MB is bound to double-stranded DNA by three modes: intercalation, semi-intercalation and electrostatic. It was revealed that at higher ionic strengths of solution complete intercalation of MB becomes thermodynamically unacceptable. It was shown that Hoechst 33258 was bound to DNA by two types – “strong” and “weak”. It was also shown that the “strong” type of Hoechst 33258 binding depends on solution ionic strength.

It has been demonstrated that the adenosine deaminase of homogeneous solutions of rat’s organs is subject to inactivation under the influence of bivalent metals (Ca²⁺, Cu²⁺, Mg²⁺), even though different levels of sensitivity to these metals are shown. Maximum inhibitory effect has been observed when adding Cu²⁺ ions to the environment.

Fibrillation of amyloid Aβ (1-42) and Aβ (1-40) peptides (Aβs) is considered as one of causes of Alzheimer’s disease. In the present work we studied the influence of some plant preparations on the aggregation state of these peptides, evaluated by fluorescence of thioflavin T-containing samples. The abilities of some preparations to inhibit the self-aggregation of Aβs and to disaggregate their preformed aggregates were demonstrated. For somecases, IC50 values in these processes were evaluated. Based on the obtained data we recommend: a) frequent use of these plants by persons at risk group; b) clinical evaluating their extracts as sources of neurodegeneration preventing agents.

In the article influence of Montivipera raddei and Macrovipera lebetina obtusa venom including phospholipase A2 (PLA2) inhibited by p-bromophenacyl bromide on giant unilamellar vesicles, visualized with 8-anilino-1-naphthalenesulfonic acid fluorescence probe, was investigated. The results have shown that both venoms even without the PLA2 activity have a noticeable membranotropic effect on the artificial membranes, but in different ways, so one can propose that investigated viper venoms can contain different PLA2 isomers.

We will always remember Karlen V. Grigorian as a citizen, famous scientist and distinguished teacher. The bright memories of him will always remain in our hearts.