Biophysics最新文献

The effect of the plant growth regulator ambiol on the functional state of mitochondria of etiolated pea seedlings was studied. The drug prevented the activation of lipid peroxidation in mitochondrial membranes in the concentration range of 10^–5–10^–6 and 10^–9 M. The introduction of ambiol into the incubation medium of these organelles resulted in an increase in the oxidation rates of NAD-dependent substrates. The most effective concentrations were 10^–5 and 10^–6 M. Changes in the bioenergetic characteristics of mitochondria were accompanied by changes in the fatty acid composition of mitochondrial membranes. The most significant changes occurred in the content of 18:2ω6 and 18:3ω3 fatty acids. It was hypothesized that an increase in the content of these fatty acids in the membranes of mitochondria indicated an increase in the content of cardiolipin, which ensured the effective functioning of the mitochondrial respiratory chain and, consequently, the maintenance of energy metabolism at a high level. The treatment of pea seeds with ambiol not only prevented a decrease in the growth rate of pea seedlings under conditions of water stress, but also stimulated their growth.

The combined effects of electrolysis and ultrasound on the population of E. coli bacteria in an aqueous solution of sodium sulfate have been studied. The kinetics of bacterial inactivation with this method for water purification have been determined. It has been shown that the combined effect of ultrasonic and electrochemical treatment of an aqueous solution significantly increased the rate of bacterial inactivation. It has been suggested that hydroxyl radicals formed during combined treatment are responsible for the death of bacteria. A correlation has been found between the rate of formation of hydroxyl radicals and the rate of inactivation of bacteria.

The relationship between the compositions of five natural water samples and the parameters of the lipid peroxidation regulation in a model system based on natural phospholipids, as well as their participation in the toxicity of natural water, have been studied. It has been shown that the presence of N- and P-containing compounds in natural water samples led to inhibition of lecithin autooxidation and luminescence intensity of luminous bacteria; it had a significant effect on spontaneous aggregation of lecithin and an increase in the content of hydrophobic compounds increased the negative value of the ζ potential of its particles. The high sensitivity of the parameters of the lipid peroxidation regulation system to the composition of natural water, even at low concentrations of its components, allows them to be considered as promising indicators for assessing the effect of natural water on biological objects. Mathematical processing of ultraviolet spectra of natural water samples using the Gauss method can be used as an express test for the analysis of its hydrochemical composition. The effect of natural water components on the state of membranes and intracellular processes of biological objects has been confirmed by biotesting methods.

X-ray diffraction was used to study oriented films formed from solutions in chloroform of egg phosphatidylcholine, the synthetic hybrid antioxidant ICHPHAN-10-C-10, and their mixtures containing 12.5 and 32 wt % of ICHPHAN. The air-dried films obtained from phosphatidylcholine and ICHPHAN were multiphase and, in addition to nonlayered lipid phases, contained the crystalline phase of ICHPHAN. With an increase in the degree of hydration of such films, the formation of a single lamellar phase consisting of lipids and ICHPHAN occurred in them. The appearance and disappearance of the crystalline phase of ICHPHAN in the films with a change in their degree of hydration was reversible. The electron density profiles of lipid membranes calculated with a resolution of ~1.2 nm showed that in the presence of ICHPHAN, the membrane thickness was reduced and the ordering of lipid hydrocarbon chains in it decreased. The results we obtained indicated the ability of ICHPHAN to integrate from the crystalline phase into lipid membranes in large quantities.

The generalized results of the study of antitumor activity, cytotoxic effect, and mechanism of action of gold (aurumacryl) and silver (argacryl) polyacrylates are presented in the context of modern ideas about the prospects for the possible use of gold- and silver-containing compounds as potential antitumor drugs based on their experimental study.

Angeli’s salt is a nitroxyl donor, due to which it can prevent the negative consequences of hemolysis, such as the vasoconstrictive effect of free hemoglobin in blood plasma. However, the molecular mechanisms of the interaction of nitroxyl with various hemoproteins have not been sufficiently elucidated. It is known that oxoferryl forms of hemoproteins arising from oxidative stress are strong prooxidants. In this study, the reductive nitrosylation of meth- and oxoferryl forms of hemoglobin and myoglobin with nitroxyl was investigated. The experiments were carried out in vitro by detecting nitrosyl forms of hemoproteins using electron paramagnetic resonance spectroscopy. The results indicate the antioxidant effect of Angeli’s salt in systems simulating the oxidation of hemoglobin or myoglobin by hydrogen peroxide. As well, the addition of hydrogen peroxide to hemoglobin and myoglobin metforms led to the appearance of an EPR signal of free radicals with g = 2.005 associated with the protein part of these hemoproteins. Thus, nitroxyl acted simultaneously as a reducing and nitrosylating agent, thereby preventing the formation of oxoferryl forms of hemoproteins. The therapeutic properties of Angeli’s salt may be largely related to the antioxidant effect exerted on blood components.

The present study is an attempt to experimentally create conditions for the occurrence of childhood myopia in laboratory animals. Measurements were performed using ultrasound technique for different age groups of Japanese quail Coturnix japonica dom., from chicks (10, 25, and 45 days) and up to fully mature birds of the (65 days) in situ. To simulate the processes of myopization, everyday lighting sources with narrow spectrum filters, blue (450 ± 10 nm), red (630 ± 10 nm), and the most eye-friendly yellow (550 ± 20 nm), were used. High-frequency focused ultrasound (30–80 MHz) and the B/Z scanning mode provided high-quality visualization of the fine structure of the chick eye and the accuracy of measuring geometric parameters in its sagittal plane. The obtained data on the size of the eyeball, the thickness of the lens and sclera, cornea, vitreous body, and chorioretinal complex made it possible to trace the age-related changes in the eye during the ontogenesis of the animal. Preliminary data on the elasticity of the sclera of the quail eye were obtained.

We have previously shown that the heteroaromatic antioxidant oxibiol (N-acetylcysteinate 6-hydroxy-2-aminobenzothiazole) inhibited the process of fructosylation of serum albumin. The purpose of this study was to elucidate the inhibitory effect of oxibiol on protein modification by photodestruction products of bisretinoid A2E, the main fluorophore of lipofuscin granules of retinal pigment epithelium cells of the human eye. It was found that the water-soluble fraction obtained from A2E-liposomes irradiated with visible light, unlike the water-soluble fraction from nonirradiated A2E-liposomes, significantly modified albumin after a day of incubation at 37°C. Oxibiol at millimolar concentrations effectively inhibited this process. The inhibitory effect of oxibiol was probably based on its antioxidant activity and the ability to competitively interact with reactive aldehydes formed during the photo-oxidative destruction of A2E-cardiolipin liposomes. The acute toxicity of oxibiol in mice with intraperitoneal administration was studied and the values of LD₁₀ and LD₅₀ were determined. The results indicated the promising use of oxibiol in pharmacology for the prevention and treatment of diseases associated with the development of oxidative stress in various fields of medicine, primarily in ophthalmology.

The aim of this study was a comparative assessment of the antagonistic activity of the culture collection strains of Lactobacillus helveticus NK1, Lacticaseibacillus rhamnosus F, and fungal kefir starter culture, as well as their metabolic complexes against representatives of Pseudomonas aeruginosa strains. As a result of the study, the high antagonistic activity of the culture collection lactobacilli, fungal kefir starter culture, and their metabolic complexes against conditionally pathogenic bacteria P. aeruginosa, both for the culture collection type strain and wild-type isolates, was confirmed. The L. helveticus NK1 strain was a more active antagonist of P. aeruginosa compared to L. rhamnosus F, which might be due to its ability to produce peptides with antimicrobial activity. These data confirmed the prospects of using the L. helveticus NK1 strain and fungal kefir starter culture for the development of a fermented milk product enriched with metabolites of probiotic cultures. The results justify further studies to determine the mechanisms of their antimicrobial action.