Vol 68, No 3 (2023)

It was shown that the release of a half of nitrosyl ligands from dinitrosyl iron units in the form of nitrosonium cation (NO⁺) from binuclear dinitrosyl iron complexes with thiol-containing ligands (B-DNIC) during DNIC decomposition in acid solutions is increased with the decrease of the stability of these complexes and completely blocked with the increase of the concentrations of free thiols (non-included into B-DNIC) up to the level that was two times and more than that of dinitrosyl iron units. It was demonstrated that the less stable B-DNIC with mercaptosuccinate degrade in an acidic environment at ambient temperature, while the decomposition of more stable B-DNIC with glutathione was only marked when the solution was heated at 80°C. The inhibition of NO⁺ release from B-DNIC in the presence of elevated free thiol level in the solution was due to the ability of free thiols to induce the reduction of NO⁺ to NO.

The inhibition of horseradish peroxidase activity by N-phosphonomethyl-glycine, an active ingredient in the most extensively used glyphosate-based herbicide (Roundup) in agricultural applications worldwide, was investigated. It has been shown that N-phosphonomethyl-glycine inhibits the activity of peroxidase from horseradish roots. This inhibition is of a competitive nature, the value of K_i = 0.1004 mM. The Michaelis constant (K_m = 0.1776 mM) and herbicide concentration (I₅₀ of Roundup = 0.302 mM) were determined. The results demonstrate that N-phosphonomethyl-glycine can suppress the activity of the antioxidant system, and in warm-blooded organisms it may cause the accumulation of free radicals, thereby contributing to expanding knowledge of biological targets Roundup is applied to.

Protein oligomers are important intermediates in the formation of amyloid fibrils. In amyloidoses, for instance, in Alzheimer's disease, oligomers are able to exert toxic effects on cells. This paper describes the distinctive features of oligomerization of multidomain muscle proteins such as smooth muscle titin and myosin-binding protein C (MyBP-C) of skeletal muscles, which consist of FnIII-like and IgC2-like domains and form amorphous amyloid aggregates in vitro. MyBP-C at low ionic strength (below physiological values) formed stable oligomers that did not participate in further aggregation. In high ionic strength conditions (µ ~ 0.6), smooth muscle titin formed oligomers, which were precursors of amyloid amorphous aggregates of this protein. The results obtained help expand existing knowledge about the process of protein aggregation.

The influence of laser radiation of a surgical laser on the physicochemical properties of bovine serum albumin molecules was studied. After exposure to laser radiation, the optical density of protein solutions increases, the fluorescence intensity decreases, a significant decrease of the intensity of the a-helix band on the Raman spectrum is observed and the refractive index of protein solution did not significantly change. However, the viscosity increased, and the pseudoplasticity of aqueous solutions of albumin decreased. There was no massive damage to the protein polypeptide chain, on the contrary, intensive aggregation was observed. Thus, in a bovine serum albumin solution subjected to contact action of laser radiation, the processes of partial denaturation and aggregation prevail, aromatic amino acid residues of the protein are damaged to a lesser extent, and fragmentation of albumin molecules is not observed.

The purpose of detecting low-frequency (relative to infrared and ultraviolet) resonance absorption of an electromagnetic field in the centimeter wavelength range using DNA molecules at a frequency corresponding to the natural frequency of torsional vibrations of the native DNA helix is to find a relationship between the length of DNA (its spectrum) and the type of a bacterium. Instead of DNA solution, cultures of different bacteria that contained DNA were used and the resonance frequencies of torsional vibrations of the helices in DNA molecules were calculated for them. The cultures were placed in test tubes or in a cuvette and were subjected to microwave irradiation. Theoretical analysis was carried out with respect to the DNA reaction to external centimeter radiation and the resonant DNA frequencies of three types of bacteria such as E. coli M17, M. avium and Mycobacterium tuberculosis were determined. Peak absorption of the ultrahigh-frequency electromagnetic field by bacterial cultures was detected at frequencies close to the calculated natural frequencies of torsional vibrations of DNA helices of the said types of bacteria: 10.271 GHz, 10.317 GHz and 10.356 GHz, respectively.

Recent advances in high-throughput sequencing methods have enabled development of an innovative approach to evaluation of genome stability and integrity. The depth of the coverage signal at a particular location of the genome may indicate the loss of DNA integrity in the region. In this work, the previously developed metric of local genome integrity that estimates the uniformity of coverage signal is considered a quantitative trait and a search for genetic variants associated with the uniformity of coverage signal in flax genome is performed. In particular, quantitative trait locus (xQTL) analyses (i.e., x Quantitiave Trait Loci, where x is the designation of an arbitrary quantitative characteristic associated with a particular genome region; for example, the level of gene expression, the degree of ribosome coverage, etc.) have been applied to identify genomic regions that most likely contribute to loss of genome integrity and are, probably, involved in the maintenance of genome stability. The analysis carried out using information on whole-genome sequence assembly of 100 flax samples enabled identification of genes potentially implicated in genome integrity maintenance in flax and, possibly, in plants in general and also revealed novel processes associated with the maintenance of genome integrity.

The article presents data as to the effect of a diet containing natural zeolite, taken from the Mysovsky mine (Khanty-Mansi Autonomous Okrug - Ugra), and applied in powdered form on the ability of erythrocytes of white outbred rats to change their shape in shear flow under normal and hypothermic conditions. To assess the deformability of erythrocytes, a laser diffraction technique combined with a redesigned version of the ektacytomer has been used in this work. For comparison, zeolite from the Kholinsky mine (Zabaykalsky Krai), which is well-studied and widely used for medicines and nutraceuticals has been provided. It has been shown that hypothermia causes a significant increase in the parameter such as erythrocyte deformability in rats in a cold group and is associated with enhanced lipid peroxidation when compared to animals in a control group. These alterations were a result of macrocytosis, revealed by flow cytometry analysis. Natural zeolite powder used in animal feeds had antioxidant and membrane-protective effects on animals in both groups. These included a significant increase in the parameter such as erythrocyte deformability with a decrease in lipid peroxidation processes and expansion of the Price-Jones curve to the left, unlike those observed in animals subjected to hypothermia but not receiving zeolites. The results obtained demonstrated that the biological effects of natural zeolite-containing preparation which contains a clinoptilolite component are similar and that zeolites from the Mysovsky mine can be used as a potent raw material for drugs.

Radiation therapy is one of the main treatments for malignant neoplasms, including breast cancer. However, it is known, that radiation therapy can lead to an increase in the number of cancer stem cells, which are resistant to traditional antitumor effects, and are believed to be responsible for the development of recurrences and metastases. Therefore, the development of cancer stem cells elimination means is of considerable interest, especially in combination with ionizing radiation. The effects of single and combined exposure to new series of minor-groove DNA ligands - dimeric bisbenzimidazoles - DBA(n) and DBPA(n) (where n is the number of methylene groups between two bisbenzimidazole blocks) and Y-radiation on human Breast cancer cells were studied in our work for MCF-7 line in vitro. Compounds with maximum cytotoxic effect and cell binding were selected, and then the effects of the latter on the CD44⁺CD24^-/low cancer stem cells population and radiation-induced epithelial-mesenchymal transition were studied by the criterion of vimentin expression. An increase in the expression level of this protein and simultaneously in the relative number of cancer stem cells after a single exposure of Y-radiation at a dose of 4 Gy were shown. DBPA(1,4) in combination with irradiation blocked the radiation-induced vimentin expression and decreased the relative number of cancer stem cells by 1.7 and 4.1 times compared with irradiation (p = 0.041 and p = 0.005), respectively. At the same time, the absolute number of cancer stem cells decreased by 2.8 and 12.0 times compared to irradiation (p = 0.029 and p = 0.004), respectively. In contrast, DBA(5,7) by itself or in combination with Y-irradiation increased the level of vimentin expression and the same compounds when combined with irradiation increased the relative number of cancer stem cells by 3.1 and 3.6 times (p = 0.006 and p = 0.005), respectively, compared with irradiation. The absolute number of cancer stem cells increased by 2.2 and 1.5 times (p = 0.017 and p = 0.032), respectively. The data obtained show a close relationship between epithelial-mesenchymal transition and formation of the cancer stem cells pool after radiation exposure, and also indicate the prospects for further study of DBPA(1,4) as a means of cancer stem cells elimination under in vivo conditions.

Effects of the 50 Gy and 100 Gy doses of Y-irradiation on radiosensitivity of cell nuclei of soft dwarf wheat seedlings were studied. Changes in the biochemical composition of the nuclear fractions of seedlings of wheat seeds exposed to gamma-irradiation were determined. After exposure to ionizing radiation, total protein and nucleic acids levels appeared to be greater in the soluble nuclear fraction and the nuclear membrane-associated DNA content and proteins increased. It was also found that the value of the dzeta-potential of isolated nuclei of seedlings of irradiated seeds decreased in a static electric field. Changes in the surface charge of the nucleus lead to a violation of its functional activity, since the surface charge of the nuclei is necessary for the normal functioning and regulation of the nuclear-cytoplasmic transport of macromolecules. Exposure to radiation causes destruction of ionogenic groups of molecules of the nuclear membrane, leading to a decrease in the electronegativity of the nuclei, which, in turn, entails a change in the functional activity of the nucleus. The results obtained show that changes in electronegativity and in the content of nuclear fractions are directly dependent on the dose of ionizing radiation. It can be concluded that Y-irradiation in a range from 50 to 100 Gy had beneficial effects on metabolic and proliferative activities of soft wheat cells.

Automatic feature extraction methods have gained increasing attention in modern image processing. The confocal images of the single-layered epithelium of the developing Drosophila eye may form an excellent model system to develop methods for complex feature extraction. The aim of this work was to explore Cartesian genetic programming for determination of the boundaries of ommatidia, the light-sensitive units in the presumptive eye region. Application of Cartesian genetic programming for the analysis of Fasciclin III expression has shown good results. This opens interesting perspectives for further use of this technology in the automatic analysis of confocal images.

The review brings together experimental data from studies aimed to uncover the opportunities for application of nanotechnology in drug therapy of malignant tumors.

A lateral flow immunoassay (LFI) is a simple, low-cost and rapid diagnostic tool to identify various diseases by detecting analytes such as antibodies, parasites, or other relevant biomarkers. However, most LFIs can only confirm the presence or absence of a target analyte being applied as qualitative diagnostic tools. In addtion, the conventional LFIs, which require visual inspection of the test line, may demonstrate insufficient sensitivity for the mild form or early detection of infections and for this reason, the result can be falsely negative. This study presents the results of employing thioglycolic acid capped CdTe quantum dots as a probe to enhance luminescence and subsequently detection sensitivity in LFIs for diagnosis of malaria. The chemical route synthesis of thioglycolic acid capped CdTe quantum dots was optimized systematically by probing optical properties of the quantum dots. These optimized quantum dots of thioglycolic acid capped CdTe have been conjugated with the anti-malaria antibodies against HRP2 protein (P. falciparum) and were then incorporated into LFIs. Further, an image processing code has been developed to carry out the quantification of malaria parasites in terms of the ratio on intensities of control and test lines on the LFIs. The results have been compared with those obtained using the standard, colloidal gold based LFIs. It has been demonstrated that sensitivity and lower detection limits of malaria under low parasite concentration increase significantly due to enhanced luminescence of control and test lines under UV light, owing to the presence of thioglycolic acid capped CdTe quantum dots. It has also been shown that the image processing based quantification of malaria will likely minimize the chances of false negative results under low parasite concentration and assist in early diagnosis of malaria.