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Extracellular vesicles (EVs) are cell-derived membrane vesicles which play an important role in cell-to-cell communication and physiology. EVs deliver biological information from producing to recipient cells by transport of different cargo such as proteins, mRNAs, microRNAs, non-coding RNAs and lipids. Adipose tissue EVs could regulate metabolic and inflammatory interactions inside adipose tissue depots as well as distal tissues. Thus, adipose tissue EVs are assumed to be implicated in obesity-associated pathologies, notably in insulin resistance and type 2 diabetes mellitus (T2DM). In this study we for the first time characterize EVs secreted by visceral (VAT) and subcutaneous adipose tissue (SAT) of patients with obesity and T2DM with standard methods as well as analyze their morphology with cryo-electron microscopy. Cryo-electron microscopy allowed us to visualize heterogeneous population of EVs of various size and morphology including single EVs and EVs with internal membrane structures in samples from obese patients as well from the control group. Single vesicles prevailed (up to 85% for SAT, up to 75% for VAT) and higher proportion of EVs with internal membrane structures compared to SAT was typical for VAT. Decreased size of single and double SAT EVs compared to VAT EVs, large proportion of multilayered EVs and all EVs with internal membrane structures secreted by VAT distinguished obese patients with/without T2DM from the control group. These findings could support the idea of modified biogenesis of EVs during obesity and T2DM., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Miroshnikova et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Large protein aggregates, known as circulating immune complexes (CICs), are formed in biological fluids as a result of the development of the body's immune response to various provoking factors. The kinetic characteristics of the formation and removal of immune complexes (ICs), their physical parameters, the isotypic composition of immunoglobulins (Igs) and the antigenic component of the CICs may reflect certain aspects of certain pathological and metabolic processes taking place in humans and animals. The aim of this study is to assess the kinetic characteristics of the formation and removal of the CICs that form in blood after eating. We also analyze the changes in the isotypic composition of Igs of ICs that accompany this biological process in rodents and humans. Methods: We identified the CICs, which differed in size and class of Igs, using dynamic light scattering. To remove ICs from the plasma, we used immune-affinity sedimentation. Monoclonal antibodies for the Igs of different isotypes were added to the plasma samples to determine the isotypic composition of the ICs. Results: A large number of ICs were formed in the blood of rats and humans after eating (food CICs). In rats, food ICs are almost immediately filtered in the liver, without circulating in the bloodstream through the body. In humans, the level of food ICs in the blood increases for 3.5 h after ingestion, then within 7-8 h their gradual removal takes place. It was found that in the process of digestion in humans, the isotypic composition of Igs in the CICs changes and becomes more diverse. Conclusions: The molecular-cellular mechanisms of the formation and utilization of food CICs in humans and rodents do not match completely., Competing Interests: No competing interests were disclosed.

Exosomes are small membrane vesicles secreted by most cell types in vivo and in vitro. Exosomes are found in cell culture media, blood, urine, amniotic fluid, malignant ascite fluids and contain distinct subsets of microRNAs and proteins depending upon the tissue from which they are secreted. Thus exosomes constitute potential biomarkers of human diseases, such as cancer. A major bottleneck in the development of exosome-based diagnostic assays is the challenging purification of these vesicles; this requires time-consuming and instrument-based procedures. Isolation of exosomes can be a tedious, non-specific, and difficult process. Here, we provide a preparative technique for isolation of exosomes based on their ability to aggregate in the presence of lectins. The new method for lectin-based isolation of exosomes from cell culture media was developed as a sample preparation step for exosome-based protein biomarker research.

The role of Tamm-Horsfall protein in pathogenesis of urolithiasis was analyzed. The study of oligomeric forms of protein was carried out using technique of dynamic light scattering. The sampling of 57 patients with urolithiasis and 51 patients of control group of comparative age and gender were examined. The degree of purification of Tamm-Horsfall protein was controlled using denaturant electrophoresis in polyacridine amyl gel. The reversing change of oligomeric form of protein with molecule size 2 Mda in polymeric form 28 Mda under impact of guanidinhydrochloride. Under urolithiasis, the form of protein associated with non-organic components and with size of macromolecular complex larger than 1500 nm was detected. The diagnostic criterion of urolithiasis was proposed based on totality of biochemical and biophysical analyses of urine.

A mirror-symmetry motif was discovered in the N-terminus of the influenza virus PB1 protein. Structure of peptide comprised of the corresponding part of PB1 (amino acid residues 6-25) was investigated by circular dichroism and in silico modeling. We found that peptide PB1 (6-25) in solution assumes beta-hairpin conformation. A truncated peptide PB1 (6-13), containing only half of the mirror-symmetry motif, appeared to stabilize the beta-structure of the original peptide and, at high concentrations, was capable of reacting with peptide to form insoluble aggregates in vitro. Ability of PB1 (6-13) peptide to interact with the N-terminal domain of PB1 protein makes it a potential antiviral agent that inhibits PA-PB1 complex formation by affecting PB1 N-terminus structure.

Changes in the rigidity of the polymetric chain of phage lambda double-strand DNA have been studied by laser correlation spectroscopy. It was shown that, as the ionic strength increases, the effect of the screening of the hydrodynamic interaction of the links of the polymeric chain specific for polymeric coils arises in a DNA solution. It is assumed that the screening occurs when the threshold of the overlapping of DNA coils is achieved. The overlapping of coils is the result of a previously observed significant rise of DNA coil size from abnormally small DNA coils in low ionic strength buffers (about 10(-2) M Na+ or less) to maximum possible large coils in the 5SSC and 5SSC-like buffers. Further analysis of the far interlink interactions in linear lambda phage DNA coils in similar buffers at pH 7 and 4 confirms the earlier proposal about the role of H+ ions in the appearance of abnormally small DNA coils. The abnormal decrease in the DNA coil size in low ionic strength buffers is not a specific feature of lambda phage DNA only.

Laser correlation spectroscopy, atomic force microscopy, and immunoaffinity chromatography were used to characterize exosomes produced by different human cells. The exosomes secreted into a culture medium by normal fibroblasts, dendritic cells, lymphocytes, as well as malignant cells obtained from tumors of various tissue origins. The similar investigations were made for exosomes detectable in plasma and cerebrospinal fluid. The dynamic light scattering technique has demonstrated that the exosomes from different sources are homogenous and similar in size of the order of 20 and 90 nm. The exceptional homogeneity of exosomes was confirmed by atomic force microscopy. The immunoaffinity method has shown that all the exosomes under study carry antigenic determinants recognizable by antibodies to the major histocompatibility complex of type 1 (HLA-ABC). A method is proposed for evidence-based detection of exosomes in various biological fluids. For this, dynamic light scattering detects 20- and 90-nm particles and whether they can be removed by immunoaffinity chromatography with HLA-ABC antibodies is checked.

The pattern of metabolic changes was studied in nuclear fuel plant workers by laser correlation spectroscopy (LCS) of biological fluids (blood serum and plasma, urine, oropharyngeal lavages (OPL). Plasma samples were divided into 3 groups: 1) control (unirradiated) samples; 2) those irradiated by below 100 mZv; 2) those irradiated by more than 100 mZv. With larger dose irradiation, the contribution of small particles (6-8 nm) to the dispersion of increased and the proportion of large components (300-400 nm) decreased. There was a correlation between the total accumulated dose, the dose in the past 9 months and the changes in the contribution of the above groups of particles to light diffusion. The found regulations in the changes of the subfraction composition of blood agree with earlier data on changes in the serum of nuclear fuel workers. Analysis of urine samples revealed an increase in the contribution of catabolic processes. That of OPL showed the preponderance of anabolic changes over catabolic ones in the presence of a considerable contribution of normologically similar LC spectra. Differences were found in the pattern of metabolic changes in relation to technological stages. Although the nature of the observed spectral transformations remains unknown, the simplicity and rapidity of the LCS technique may be considered as a suitable tool for detecting the effects caused by small dose irradiation and other factors.

Tamm-Horsfall uroprotein accounts for more than 50% of the urinary proteins in healthy individuals. In abnormalities, it creates a favorable background for detecting smaller-sized uroproteins and for diagnosing pathological processes from the results of native urine tests. In this connection, there is a need for precipitating Tamm-Horsfall glycoprotein while applying laser correlation spectroscopy to analyze the size of urine particles in patients with type 2 diabetes mellitus. Eighty patients with this condition concurrent with different stages of diabetic nephropathy and 23 apparently healthy individuals were examined. The findings suggest that the subfraction urine composition before and after Tamm-Horsfall protein precipitation is different in apparently healthy individuals and patients with type 2 diabetes mellitus concurrent with diabetic nephropathy. This is most likely to be due to the change in the qualitative composition of protein as renal lesion progresses, to the specific features of protein excretion at different stages of a pathological process, and to different concentrations of other low and high molecular-weight proteins.

Using the method of laser correlation spectroscopy of biological fluids (blood serum, urine, oropharyngeal washout fluid) we studied the types of metabolic shifts in workers employed in nuclear fuel complex plant. In was found that the incidence of catabolic shifts considerably increased in workers with higher level of occupational exposure. In individuals contacting with open radiation sources we found the contribution of anabolic immunomodifying shifts with predominance of autoimmune sensibilization. A risk group for blood diseases was identified.

A combination of two methodical approaches (parallel evaluation of the psychomotor function and metabolic shifts) was used in examination of children with scoliosis. We evaluated adaptation of children at the certain stage of the disease for prediction of its further course and correction of the treatment.

Three thermo- and radiosensitive mutants of yeast-Saccharomyces were used to study cell inactivation under the effect of elevated temperature, UV-light, and ionizing radiation. The forms of cell inactivation were shown to be identical with all the factors under study and to resemble lethal "terminal phenotypes" of Hartwell cds mutants. It is suggested that the cell division cycle is blocked due to the disorders in the system of gene product synthesis and not to defects in the enzymes themselves.

The purpose of this work was to test the possibility of using a luminescent variant of the Feulgen reaction with the reagent auramine-SO2 for staining yeast cell nuclei in order to determine the content of DNA in them. Reproducibility and stability of results obtained by this method suggest that it can be used to control the ploidy of the nuclei from yeast cells belonging to one and the same species.