Despite the great interest of scientists in the question of what cell aging is, and the long history of its study, there are still many contradictions in this area. They arise because several different approaches have been developed to model aging in vitro. As a result, even different terms arose – cell senescence and cell aging. There are not only differences between models for studying aging at the cellular level, they also have common features. Moreover, it is now becoming apparent that some models complement others. This is evidenced, in particular, by the fact that biomarkers used in one model are suitable for use in another (aging-associated β-galactosidase, lipofuscin, etc.). The development of approaches to the study of cellular aging has been uneven, and at present, research on this topic is experiencing another rise due to the prospects for the use of senolytics (drugs that selectively eliminate “senescent” cells) to increase the lifespan of multicellular organisms. This review considers the pros and cons of various models for studying aging on cultured cells of various nature.

In the present study, Chlorella-like strains of green microalgae from various commercial biological products were studied for the first time using morphological and molecular genetic analyses. It was found that representatives of the Chlorella clade or sister Parachlorella clade were present in all analyzed samples. In addition, microalgae from the genera Edaphochlorella, Chloroidium, Edaphochloris and Muriella belonging to the Trebouxiophyceae class, as well as Coelastrella and Chromochloris belonging to the Chlorophyceae class were found. According to direct light microscopy data, filamentous cyanobacteria were observed in all preparations, and the presence of diatoms was also noted in the biopreparation “Gera”. Since the correct identification of green microalgae based on phenotypic traits is very difficult due to their scarcity, lack of information and variability, the control of the composition of microalgae in biological products should be carried out using modern molecular genetic methods.

Currently, the problem of effectiveness reduction of the anti-tuberculosis drugs is associated not only with the development of drug resistance by the pathogen, but also with the activity of the multidrug resistance protein P-gp (P-glycoprotein) of macroorganism cells. Rifampicin, the main anti-tuberculosis drug, is a substrate for P-gp. The article presents data on the activity of P-gp in pro-inflammatory human macrophages and assesses the effect of a new form of the anti-tuberculosis drug – rifampicin-loaded lactic acid polymer nanoparticles – on it. Scanning electron microscopy, laser confocal microscopy, MTT test and flow cytometry methods were used. It was shown that the new form of rifampicin is non-toxic for human monocytes and macrophages of the THP-1 cell line. In addition, it activates the processes of endocytosis/ phagocytosis and reduces the functional activity of P-gp. Thus, it seems promising to develop encapsulated anti-tuberculosis drugs – with phagocytosis-activating properties that specifically affect certain features of human macrophages.

Fast sodium current (I_Na) provides depolarization of working myocardium and defines the excitability of its cells and the velocity of excitation propagation in the tissue. Alterations in activation and inactivation of I_Na channels can lead to the onset of various arrhythmias. Cardiac I_Na is poorly studied in most vertebrate animals (excepting mammals) – including birds which are of great interest for comparative physiology. In the present work we for the first time study the characteristics of fast sodium current in myocardium of adult bird. Using standard patch clamp method, we recorded I_Na in isolated atrial and ventricular cardiomyocytes of Japanese quail. The current had great amplitude and quickly recovered from inactivation both in atrial and ventricular cells; the fast inactivation time constant of I_Na in atrial cells was lower than that of ventricular cells. Steady-state activation and inactivation suggest that sodium window current in avian myocardium is less pronounced in comparison to that in mammalian heart. In quail ventricular myocytes the blocker of late sodium current ranolazine caused a slight decrease in peak current amplitude and did not affect inactivation – however, it shifted steady-state inactivation curve towards more negative potentials, shortened action potentials and caused a decrease in maximum upstroke velocity. Thus, the characteristics of I_Na in quail myocardium reflect an adaptation to high heart rates in birds, and also suggest possible differences in the structure and function of I_Na channels between birds and mammals.

Chlorophyll fluorescence methods were used for study of phytoplankton in the Kislo-Sladkoe Lake on the White Sea coast in 2018. In the chemocline (between aerobic and anaerobic zones) of the lake at a depth of 3.3 m a red water layer was observed with chlorophyll a concentration of 1.7 μg/L, despite the presence of hydrogen sulfide. This water layer was dominated by cryptophyte algae (Rhodomonas sp.), in which a high functional activity of the photosynthetic apparatus was observed in terms of the PI_ABS fluorescence parameter, expressed through high values of the quantum yield of the primary photochemical reaction in PS2 (F_V / F_M), the proportion of active RCs (RC/ABS), and the quantum yield of electron transport in PS2(φ_Eo). Such a high functional activity of the photosynthetic apparatus of cryptophyte algae in the chemocline may indicate the resistance of cryptophyte algae to the presence of hydrogen sulfide. By comparison, the phytoplankton in the surface water layer showed lower photosynthetic activity. Experiments with photoinhibition showed that the chemocline phytoplankton community is characterized by a greater reparative capacity after photooxidative stress despite the increased photosensitivity. Application of chlorophyll fluorescence methods for study of the state of phytoplankton in stratified meromictic water bodies is proposed.

Тo activate respiratory metabolism Lacticaseibacillus rhamnosus CM MSU 529 was grown in a batch culture under intensive aeration in the presence of 38 μM hemin and 18 μM vitamin K₂ as a source of menaquinone. Unsupplemented aerobic culture served as a control. Supplementation of the growth medium with hemin or menaquinone separately had no significant effect on culture growth. Biomass concentration of 2,86 ± 0,05 g dw cells/l and the yield coefficient for biomass Y_P/S of 25,6 ± 1,5 g dw cells/mol glucose consumed were determined after 24 h and 18 h of cultivation under respiratory conditions (hemin + K₂) respectively. Both values were 27% higher compared to those for aerobic conditions. Spectral analysis revealed the presence of cytochromes b- and d-type in membranes of L. rhamnosus CM MSU 529. The activity of bacterial electron transport chain was investigated by polarographic technique. Membrane preparations obtained from cells grown aerobically on hemin-containing medium intensively consumed oxygen in the presence of 1 mM NADH. Addition of 0.2 mM menaquinone to reaction mixture caused the increase of NADH oxidation rate by 4.6 fold. Enzymes presumably involved in NADH oxidation by membranes were identified using MALDI-TOF MS/MS: pyridine nucleotide-disulfide oxidoreductase (Nox-2), NADH dehydrogenase 2 (Ndh-2), and ubiquinol oxidase bd subunit I (CydA). Thus, during NADH oxidation 80% of electron transport from NADH to oxygen went via Ndh-2, menaquinone, bd-type quinol oxidase and only 20% – via Nox-2. The study presents experimental evidence for electron transport chain functioning in L. rhamnosus CM MSU 529 during aerobic cultivation with hemin and menaquinone. The NADH oxidation rates of membrane preparations of lactic acid bacteria were measured for the first time. The property of exogenous menaquinone to transfer electrons from Ndh-2 to bd-type quinol oxidase was demonstrated for the first time in vitro in lactic acid bacteria.

Fibrillar proteins play a significant role in the living organisms functioning, and recently much attention has been paid to them as targets in the therapy and diagnosis of various diseases, substrates for the biopolymers production, as well as industrially important proteins that are key agents in the textile and food manufacture. To implement the development of these directions, fibrillar proteins hydrolysis and processing methods are needed, the most promising of which is the use of proteolytic enzymes. 11 enzyme preparations obtained by cultivation of micromycetes belong to the genus Aspergillus and containing from 1 to 10 proteins were studied for the ability to hydrolyze fibrillar proteins: collagen, keratin, fibrin and elastin. The proteolytic enzymes of A. alliaceus 7dN1, A. clavatus A16, and A. ustus 1 showed an activity comparable to or higher than that of the commercial preparation Terrilitin used in wound therapy. The A. fumigatus D1 enzyme preparation also showed high level of fibrinolytic activity.

Elevated level of circulatory interleukin 6 (IL-6) is a biomarker for cytokine storm of various etiologies including COVID-19 and contributes to poor prognosis. Vascular endothelial cells are one of the main targets of pathological action of IL-6. IL-6 activates trans-signaling pathway via the formation of the IL-6/sIL-6Ra/gp130 receptor complex and subsequent activation of the JAK/STAT3 signaling pathway, and in some cases PI3K/AKT and MEK/ERK kinases. Previously, by our group and other researchers, it was shown that reactive oxygen species (ROS) including mitochondrial ROS (mito-ROS) contribute to the induction of IL-6 expression in the endothelium, mainly due to increased activation of the transcription factor NF-kB. We have also shown that the mitochondria-targeted antioxidant SkQ1 (plastoquinolyl-10(6’-decyltriphenyl) phosphonium) prevented tumor necrosis factor (TNF)-induced cytokine storm and death in mice. In the aortas of these animals, SkQ1 also prevented the increase in the expression of NF-kB-dependent genes, including the cytokine IL-6 and the chemokine MCP-1. In the current work, we have tested the hypothesis of mito-ROS involvement in the IL-6-signaling-mediated pro-inflammatory gene expression in endothelial cells. SkQ1 suppressed the expression and secretion of the MCP-1 chemokine, induced by IL-6 in combination with sIL-6-Ra, but not the expression of ICAM1 adhesion molecules in EA.hy926 human endothelial cells. Using specific inhibitors, we have shown that in EA.hy926 cells, IL-6-induced expression of MCP-1 and ICAM-1 depends on the signaling protein and transcription activator STAT3 and, in some cases, on JNK, PI3K, and MEK1/2 kinases and is independent of p38 kinase. In this model, IL-6 induced rapid STAT3 activation while ERK1/2 activation was less pronounced, and there was no IL-6 effect on Akt and JNK activation. SkQ1 partially suppressed STAT3 and ERK1/2 activation. Thus, we have shown that SkQ1 suppresses not only NF-kB-dependent expression of IL-6 and other proinflammatory genes, but also IL-6-induced activation of JAK/STAT3 and STAT3-dependent expression of MCP-1, which probably contributes to the overall therapeutic effect of SkQ1.