Vol 62, No 3 (2017)

A systemic regularity of molecular biology is considered: the tendency towards alternating of the sense of chirality of intramolecular structural levels of DNA and proteins, namely, D–L–D–L for DNA and L–D–L–D for proteins, is observable starting from the level of asymmetric carbon in deoxyribose and amino acids. Helicity is a special case of chirality. In intermolecular interactions, the sense of chirality of the highest intramolecular structural level directly involved in the interaction prevails in each of the participants. The interaction of molecules of the same nature (protein–protein, DNA–RNA, tRNA–mRNA, and ribozymes) mainly occurs in the case of the same sense of chirality, either L–L or D–D, and for molecules of different types (DNA–protein, tRNA–amino acids, and enzyme–substrate), in the case of different senses of chirality, either D–L or L–D. An alternating sense of the chiral hierarchy of conjugated levels of macromolecular structures in proteins and nucleic acids is of general biological importance: it determines the discreteness of levels, serves as a tool of folding, and provides a structural basis for “preferred collective” (or “macroscopic mechanical”) degrees of freedom in the design of macromolecular machines, as well as being one of the mechanisms of blockwise/saltatory development of the evolutionary process. A new fundamental concept is proposed: the homochirality of primary structures of DNA and proteins determines the amount of the entropic component of the free energy, which is used in the processes of folding and molecular rearrangements.

The Langevin dynamics method and statistical correlation analysis were used to study the α-helical structure folding dynamics of the (Ala)₅₀, (AlaGly)₂₅, and (AlaGly)₇₅ polypeptides depending on the viscosity of the medium. Friction forces that arise when the effective viscosity of the medium is similar to the viscosity of water were found to result in strong correlations between the backbone torsion angles. The polypeptides under study folded mainly to produce α-helical structures. A structure of two contacting α-helices that were approximately equal in length and had a loop between them was observed for a longer chain of 150 residues. A method to visualize the correlation matrix of the dihedral angles of a polypeptide chain was developed for analyzing the effects of the dynamic correlation of conformational degrees of freedom. The analysis of the dynamics of the correlation matrix showed that rotations involving angles of the same type (φ–φ and ψ–ψ) occur predominantly in one direction. Rotations invoving different angles (φ–ψ) occur predominantly in opposite directions, so that the total macromolecule does not rotate. A significant reduction in the effective viscosity of the medium disrupts the correlation and makes the rotations stochastic, thus distorting the formation of the regular (helical) structure. The effects of correlated conformational motions are consequences of viscous friction forces. This conclusion agrees with our previous results that outlined the principle of the minimum rate of energy dissipation and the equipartition of energy dissipation rate between conformational degrees of freedom.

The comparative study on the secondary structure of DNA isolated from the liver tissue of normal rats, as well as from the tumor tissue of rats both treated and untreated with porphyrins was carried out. meso- Tetra(4-N-hydroxyethylpyridyl)porphyrin and its Ag, Zn, Co derivatives (H₂TOEPyP4, AgTOEPyP4, ZnTOEPyP4, CoTOEPyP4) were studied as potential anticancer drugs. A method that allows revealing the conformational state of DNA via the study of the effects of transition metal ions, such as Mn²⁺, on the intramolecular melting was used in the work. DNA melting was carried out in the presence of different stoichiometric concentrations of Mn²⁺ ions. The main melting parameters, the melting temperature and the melting range (T_m and ΔT), were calculated. The melting parameters of DNA isolated from tumor tissue differed from those of normal DNA. The melting parameters of DNA isolated from rats treated with porphyrins were close to the normal ones. The results showed that AgTOEPyP4 and ZnTOEPyP4 have a better antitumor effect than H₂TOEPyP4 and CoTOEPyP4.

The possibility of detecting bacteriophages using phage mini-antibodies by the electroacoustic analysis method using bacteriophages FA1-59b was shown. It was found that the frequency dependence of the real and imaginary parts of the electrical impedance of a resonator with a suspension of phages and the appropriate antibodies significantly differs from that of the resonator with a control virus suspension without addition of mini-antibodies. The amount of FAl-Sp59b bacteriophage in the analyzed suspension varied from ~10¹⁰ to 10⁶ phage/mL; the analysis did not take longer than 5 min. The change in the real or imaginary parts of the electrical impedance at the fixed frequency near the resonance after addition of specific mini-antibodies in the suspension appeared to be an optimal information parameter to obtain reliable information. These results may allow the development of a biological sensor to identify and quantify viruses in the liquid phase.

A stoichiometric model that combines the reactions of central metabolism and the electron transport processes of respiration and primary photosynthetic reactions in a plant cell is considered. The central metabolic reactions, including glycolysis, the Calvin cycle, and the Krebs cycle, are associated with electrontransport processes via the NAD(P)H redox equivalents. The model is defined by algebraic equations and includes rules that enable the description of the change in the direction of metabolism dependent on the availability of different carbon sources. Experimental data on the changes of the levels of individual cellular metabolites in the alga Chlamydomonas reinhardtii under the conditions of sulfur deprivation were used to verify the model. The model allowed the generalization of the existing concepts of the changes in the direction of metabolic fluxes under the conditions of sulfur starvation.

Echinochrome A (6-ethyl-2,3,5,7,8-pentahydroxy-1,4-naphthoquinone) isolated from the body of sand dollar Scaphechinus mirabilis is an active substance of cardioprotective medication Histochrome and exerts a wide spectrum of anti-inflammatory activities. In the present paper, we conducted a comparative study of the antioxidant (radical-scavengering) properties of echinochrome A in 2,2′-azobis(2-methylpropionamidine) dihydrochloride−luminol and hemoglobin−hydrogen peroxide−luminol systems and assessed its impact on permeability of planar bilayer lipid membranes. Trolox was used as a reference antioxidant and ascorbic acid and dihydroquercetin are taken as standards. Echinochrome A shows moderate antioxidant activity, possessing higher antioxidant capacity than Trolox and ascorbic acid, but exhibiting lower antioxidant potential compared with dihydroquercetin in tests for antioxidant activity in both investigated systems. The test substances can be arranged in the following order according to the effectiveness of the antioxidant effect: dihydroquercetin > echinochrome A > Trolox > ascorbic acid. Echinochrome A does not lead to significant changes in the permeability of planar bilayer membranes in a dose range of 1.5 to 30 μМ. Our data indicate that echinochrome A has a rather high level of radical-scavengering activity without a primary membranotropic effect. It is thought that the high levels of the cardioprotective and anti-inflammatory activities of echinochrome A may be due not only to the ability of this substance to neutralize reactive oxygen species, but also to its capacity to generate physiological concentrations of hydrogen peroxide molecules in biological systems as signaling messengers of various metabolic processes and biochemical pathways. The suspected mechanisms of the biological activity of echinochrome A are discussed.

The contents of lipids in the tissue and the nuclei of liver cells during artificial hypobiosis, as well as in the nuclei of liver cells for 3 days after the cessation of cooling in rats, were studied. In the artificial hypobiosis and in the state of normothermia 24 h after the cessation of cooling, the total phospholipid content of the liver cell nuclei increased by 20% due to minor phospholipids. The levels of sphingomyelin, phosphatidylinositol, phosphatidylserine, cardiolipin, and lysophosphatidylcholine were doubled in hypobiosis and then nonmonotonically returned to the normal level within 72 h. In the state of artificial hypobiosis, the levels of fatty acids, cholesterol, and diglycerides increased by 30–40%. The state of artificial hypobiosis did not affect the level of lipids in the liver tissue of Wistar rats. The increase of the lipid content in the liver cell nuclei of Wistar rats indicates the important role of lipids in functions of the nucleus when the energy supply and protein synthesis are inhibited under conditions of artificial hypobiosis.

The oxygen consumption rate in red blood cell suspensions of two Black Sea fish species, a cartilaginous fish, the common stingray (Dasyatis pastinaca L.) and the teleost black scorpionfish (Scorpaena porcus L.) has been studied. The proposed stimulants of activators and inhibitors of the mitochondria electron transport chain had very predictable responses, indicating that mitochondria in fish erythrocytes have a classical set of respiratory enzymes. Despite the fact that the basic respiratory activity of common stingray erythrocytes was greater than those of the scorpionfish, the responses of common stingray red blood cells to the exposure during investigation of the respiratory activity of the mitochondria have an inverse relationship. The oxygen consumption rates in suspensions of scorpionfish erythrocytes in response to the stimulant were higher according to both the amplitude and the duration of the response. Investigations have shown the high energy potential of the red blood cell mitochondria of the scorpionfish and stingray. This may be the energy basis for maintaining the high intracellular concentrations of ATP required not only to keep an adequate level of intracellular metabolism, but also to provide a special mode of blood flow through the capillary beds.

The damaging effects of light that was emitted by a DRSh250-3 mercury lamp on the DNA of mouse blood leukocytes was studied in vitro. It was shown that the main DNA damage is due to the action of UVB radiation (280–320 nm). Under the combined effects of the UV radiation and the orange–red fluorescent component it was found that the additional fluorescent light with the spectral maximum at 625 nm from nanoluminophore materials (quantum dots that are based on CdSe/ZnS, CdSe/CdS/ZnS) protected the cellular DNA from the damaging effect of UV radiation. Using nanomolar concentrations of hydrogen peroxide, the hypothesis of the role of reactive oxygen species in the protective effects of the red–orange light was tested in vitro. It was shown for the first time that the mechanisms of the protective effects are associated with the induction of an adaptive response by nanomolar concentrations of hydrogen peroxide that are induced by the orange–red light.

The formation of dinitrosyl iron complexes with thiol-containing ligands in plant tissues (parsley and apple leaves) in the presence of nitric monoxide was demonstrated using electron paramagnetic resonance. In two types of tissues dinitrosyl iron complexes are predominantly represented by the binuclear diamagnetic form. This diamagnetic form can be transformed in EPR-detectable mononitrosyl iron complexes with diethyldithiocarbamate due to the ability of diethyldithiocarbamate to accept the iron-mononitrosyl groups from iron-dinitrosyl fragments of binuclear complexes. A similar transformation was observed under the effect of diethyldithiocarbamate on a mononuclear paramagnetic form of dinitrosyl iron complexes. The significant amount of binuclear dinitrosyl iron complexes found in plant tissues suggests that these complexes can be considered as a “working form” of nitric monoxide, which is recognized now as a universal regulator of metabolic processes in plants as well as in other organisms.

The effects of terahertz radiation (0.1–2.2 THz) on the dynamics of reaching the imago stage by drosophila of the F1 progeny obtained from the crossing of irradiated and unirradiated parental individuals in different combinations were studied. A shift in the maximum emergence peak for an earlier period and a shortening of the period of reaching the adult state were found in the progeny of both sexes obtained from irradiated females. The development up to the imago stage significantly differs in the progeny of irradiated males and irradiated females in a number of parameters. It was suggested that the effect of terahertz radiation on the dynamics of the onset of the imago stage can be associated with one or different mechanisms that change the expression of the genes and signaling pathways that control the development of drosophila.

A significant antitumor activity of aqueous solutions of binuclear dinitrosyl iron complexes with glutathione was found when they were injected intravenously in a model of a solid malignant tumor, that is, Lewis carcinoma, in mice. Dinitrosyl iron complexes completely inhibited the tumor growth (by 100%) at doses of 20, 10, and 2 μmol/kg in the first 11 days after the beginning of experiment followed by tumor proliferation at a rate that was lowest for the lowest of the used doses. At day 16, the inhibition of tumor growth was 90% when a solution of dinitrosyl iron complexes was injected at a dose of 2 μmol/kg five times with an interval of 2 to 3 days between injections; whereas the inhibition of tumor growth did not exceed 70 and 30% at doses of 10 and 20 μmol/kg, respectively. Acceleration, rather than inhibition of carcinoma growth was observed at a dose of 100 μmol/kg. The tumor weight increased 1.5–2.0 times compared to the control values, depending on the time.

Spectra of radiation penetration depth into the blood and skin tissues were calculated for the wavelength range of 405 to 950 nm with the optical properties of biological tissues taken into account. The proportion of radiation that reached the blood in the blood vessel in the case of supravenous irradiation of blood was estimated. Optimal wavelengths that allowed efficient formation of molecular oxygen in the blood due to photodissociation of oxyhemoglobin upon intravenous and supravenous irradiation of blood were determined. Changes in blood oxygenation parameters characteristic of phototherapy, such as the degree of hemoglobin saturation with oxygen, oxyhemoglobin concentration, partial pressure of oxygen, and the concentrations of certain products of metabolism initiated by the photodissociation of oxyhemoglobin, have been demonstrated for optical radiation of different wavelengths. The physical causes of changes in oxygenation characteristics and metabolic product levels induced by photohemotherapy are considered.

Secreted reporter proteins provide monitoring of intracellular events in real time without cell destruction. To create human melanoma cell lines that enables noninvasive bioluminescent monitoring of metabolic activity, a comparison of the efficiency of isoforms and mutant variants of luciferase from the Metridia longa as secreted reporter proteins in the cells of human melanoma lines Mel IL was conducted. The MLM3 deletion mutant had the highest activity in the medium of two studied isoforms and two deletion mutants of secreted M. longa luciferase during the Mel IL melanoma cell transfection. It was established that optimization of the gene structure of the selected MLM3 variant for expression in human cells increases the level of bioluminescent activity in the Mel IL cells by almost an order of magnitude. A stable Mel IL melanoma cell line with constitutive expression of the humanized hMLM3 reporter gene was obtained and characterized. The linear range of identification of living cells by the hMLM3 reporter activity was more than three orders of magnitude with a sensitivity of detection of 10 cells.