Biophysics最新文献

Changes in the activity of the angiotensin converting enzyme and the production of reactive oxygen species in the rat aorta during diabetes induction by alloxan have been studied. The activity of the angiotensin converting enzyme in the aortic segments was determined by the hydrolysis of hippuryl-L-histidyl-L-leucine and the formation of reactive oxygen species was determined by the oxidation of dichlorodihydrofluorescein. It has been shown that the activity of the angiotensin converting enzyme increases with an increase in blood glucose concentration to a maximum value at a glucose concentration of 12 mM and does not increase with a further increase in glucose levels. In contrast to the activity of the angiotensin converting enzyme, the formation of reactive oxygen species increases with increasing glucose concentration over the entire studied concentration range (up to 24 mM). Experiments with enalapril, an angiotensin converting enzyme inhibitor, have shown that it completely prevents an increase in the rate of formation of reactive oxygen species up to a glucose concentration of 12 mM (100% contribution of activation of angiotensin converting enzyme to an increase in the formation of reactive oxygen species), but at higher levels the effectiveness of enalapril decreases (about 30% contribution of activation of angiotensin converting enzyme to an increase in formation of reactive oxygen species).

Pioneering transcription factors from the Yamanaka cocktail carry out cell reprogramming. These proteins bind to heterochromatin, promote its opening, and attract proteins to alter the epigenetic landscape and activate transcription. However, there is no information in the literature about which chromatin proteins are attracted through direct protein-protein interactions with pioneer transcription factors. In this study, we used neural network algorithms to predict potential protein-protein complexes of three proteins from the Yamanaka cocktail (SOX2, OCT4, and KLF4), and performed a structural and functional analysis of the resulting complexes.

The aim of this work was to analyze the interactions of methyl-β-cyclodextrin and amphotericin B (AmB) with spectrin, actin, and hemoglobin by the method of molecular docking. The protein structures were taken from PDB. The full-atom models of proteins were “cleaned” of water molecules and buffer components, surface charge arrangement was performed, and cells were selected for “blind” docking. The structural formulas of methyl-β-cyclodextrin and amphotericin B were taken from PubChem and converted to HyperChem. Geometrical optimization was performed using the MM+ model potential; rigid/fixed structures were optimized using the PM3 semi-empirical quantum chemical method. The protein–ligand complex interactions were described using PLIP. The total binding energy for all complexes ranged from –4.4 to –10.3 kcal/mol. The complexes were formed due to hydrogen and van der Waals bonds and salt bridges. Visualization of the most energetically advantageous positions confirmed that both amphotericin B and methyl-β-cyclodextrin were located in the central cavities of hemoglobin and actin and in the distal sites of the α- and β-subunits of spectrin. Amphotericin B formed more stable complexes with each of the proteins: the strength of hydrogen bonds and the number of hydrophobic contacts with the proteins were higher than for complexes with methyl-β-cyclodextrin.

An overview of data on studies of multi-vector, as well as the persistence of unidirectional synaptic modulation in various types of motor units, is presented. As is known, modulators of synaptic transmission are numerous. These include the main mediators directly involved in this synapse, neuropeptides (endorphins and enkephalins, calcitonin, substance P, etc.), fatty acid derivatives (arachidonic acid and eicosanoids), gaseous mediators (NO, CO, and H₂S), as well as purines and pyrimidines (extracellular ATP, adenosine, etc.). Using the example of data analysis based on the results of the action of the most effective neuromodulators, purines, both their constant and variable effects in the synaptic modulation of various types of skeletal muscles were revealed.

The possibility of combined use of compounds containing precious metals, gold, silver, and cisplatin polyacrylates in experimental animal tumor models has been investigated. An additive effect has been found upon combined use of cisplatin and aurumacryl (Acatol adenocarcinoma and Lewis lung carcinoma) and the therapeutic synergism of the combination of cisplatin with argacryl (Lewis lung carcinoma). A tumor that recurs after exposure to cisplatin retains the sensitivity inherent in the original tumor to both cisplatin and argacryl (Lewis lung carcinoma).

The effect of 30-day antiorthostatic hanging of male Mus musculus mice on spermogram parameters, including the use of essential phospholipids, was studied. The concentration and motility of spermatozoa were measured and the fertilizing ability, the content of cholesterol, calcium ions and cytoskeletal proteins in spermatozoa were assessed. To assess the specificity of changes in spermatozoa, the contents of cholesterol and cytoskeletal proteins were determined using buccal epithelial cells. It was shown that anti-orthostatic hanging led to a decrease in the proportion of fertilized oocytes and the absence of 2–4-cell embryos, but the use of essential phospholipids prevented these changes. The observed increase in the cholesterol content in spermatozoa, which is nonspecific due to similar changes in buccal epithelial cells, in response to anti-orthostatic hanging, as well as the accumulation of calcium ions, could change the effectiveness of capacitation and cause a decrease in fertilizing capacity, which requires further research.

Mitochondrial DNA deletions are a recognized factor in mitochondrial disorders and aging. The purpose of this work was to study the prevalence of large-scale mitochondrial DNA deletions in peripheral blood samples from offspring whose parents were the employees of the Mayak Production Association, who were exposed to combined external gamma and internal alpha irradiation in the preconception period. By PCR amplification of extended fragments, a 4977 bp deletion and deletions ranging in size from 7436 to 8044 bp were detected. It was found that the prevalence of deletions in the studied groups of these offspring shows a tendency to increase, but there were no statistically significant differences with the control group.