Biochemistry (Moscow), Supplement Series A: Membrane and Cell Biology最新文献

The processes of electron transport in the leaves of two species of plants of the genus Cucumis, the shade-tolerant species Cucumis sativus (cucumber) and the light-loving species Cucumis melo (melon), grown under moderate (50–125 µmol photons m^–2 s^–1) or strong illumination (850–1000 µmol photons m^–2 s^–1) were studied. The parameters of fast and slow induction of chlorophyll a fluorescence were used as indicators characterizing the activity of photosystem 2 (PS2). The functioning of photosystem 1 (PS1) was monitored by changes in the electron paramagnetic resonance signal from the oxidized reaction centers of PS1, ({text{P}}_{{700}}^{ + }). A significant difference was revealed in the dynamics of changes in photosynthetic parameters of shade-tolerant (C. sativus) and light-loving (C. melo) species during their acclimation to moderate or high light intensity. In the shade-tolerant species C. sativus, photosynthetic indicators characterizing the activity of PS2 showed a noticeable sensitivity to increased illumination compared to the light-loving species C. melo, indicating a weakening of the activity of PS2 with an increase in light intensity during acclimation of plants. During a long-term (more than 1–2 months) acclimation of C. sativus to high intensity light (≥500 µmol photons m^–2 s^–1), their PS2 lost photochemical activity, which, however, was not observed in the leaves of C. melo. The weakening of the activity of PS2 in the leaves of C. sativus was reversible, that is, after returning to light of moderate intensity, the activity of PS2 was restored to the level characteristic of the leaves of C. melo. In the leaves of plants of both species, differences in the kinetics of photoinduced redox transformations of the reaction centers of PS1 were manifested, depending on the acclimation conditions. In plants acclimated to strong light, there was a clearly pronounced delayed phase of signal from ({text{P}}_{{700}}^{ + }) growth, which presumably could be caused by cyclic electron transport (CET) around PS1. The ratio of the amplitudes of EPR signals from ({text{P}}_{{700}}^{ + }) under the white and far-red light (707 nm) became higher in plants grown under strong light. This might be due to an increase in CET, which helped to optimize the energy balance and reduce light stress when there was an excess of illumination. The results obtained are discussed in the context of the task of optimizing photosynthetic processes during plant acclimation.

We studied the mutual influence of multipotent mesenchymal stromal cells (MMSC) isolated from human umbilical cord Wharton’s jelly and primary culture of hippocampal cell from transgenic (Tg) 5XFAD mice, a model of familial Alzheimer’s disease (AD). Antibodies to human nuclear antigen were used to identify MMSCs in “chimeric culture”; the cells belonging to neurons or astrocytes were determined by the presence of positive immunoreactivity to marker proteins MAP2 and GFAP. It was shown that the result of the interaction depends on both the cocultivation method and the age of the culture. In indirect (non-contact) cocultivation, the aggressive environment of the transgenic culture affected the survival rate and impaired the adhesive properties of the MMSCs. Pretreatment of these cells with stress proteins YB-1 and HSP70, which possess neuroprotective properties, increased the resistance of MMSCs. In young culture during contact cocultivation, the MMSCs play the role of specific strands that promote grouping of hippocampal cells of transgenic mice and formation of neurospheres. In old transgenic cultures, irrespective of the cocultivation method, the MMSCs differentiated into astrocytes, but during prolonged direct cocultivation, a part of MMSCs became immunopositive to the neuronal marker MAP2. The work shows that the interaction between the MMSCs and the hippocampal cell culture can be carried out with the participation of gap junctions as well as due to the formation of nanotubes. The results obtained indicate the presence of a complex relationship between donor MMSCs and recipient cells, which must be taken into account when introducing cell therapy into the practice of treating AD patients.

BAR proteins are key components of the synaptic vesicle cycle in nerve terminals. They participate in the regulation of neurotransmitter release during the fusion of synaptic vesicles with the presynaptic membrane and synaptic vesicle recycling. Localization of these proteins at the sites of liquid–liquid phase separation in nerve terminals suggests additional functions of these molecules. In the current review, we discuss the tasks of BAR proteins at different stages of the secretory cycle, including their putative role in liquid–liquid phase transitions in nerve terminals during synaptic activity. We suggest that BAR proteins, along with their established functions in exo- and endocytosis, play crucial roles in the organization of the reserve pool of synaptic vesicles and at intermediate stages of the vesicle cycle.

This work is aimed to develop several cationic amphiphiles based on amino acid derivatives of diethanolamine as potentially membrane-active antibacterial agents. The developed compounds contain two amino acid residues in the polar block and aliphatic chains of various length in the hydrophobic domain. Amphiphiles were obtained in preparative amounts sufficient to confirm their structures and perform a study of antibacterial activity. The synthesized samples based on β-Ala (4c) and GABA (4d) with aliphatic C12 chain in the hydrophobic domain showed a promising level of antimicrobial activity against gram-positive (B. subtilis) and gram-negative (E. coli) bacteria (minimal inhibitory concentration, MIC, 1 μg/mL). Amphiphiles containing aromatic amino acids L-Phe (6a) and L-Trp (6b) in the polar head group and C8 hydrocarbon chain exhibited an antibacterial activity against B. subtilis with MIC of 1 μg/mL. The obtained data on antimicrobial activity make the selected compounds attractive for further detailed study of their mechanism of action.

The new coronavirus infection (COVID-19) pandemic caused by SARS-CoV-2 has many times surpassed the epidemics caused by SARS-CoV and MERS-CoV. The reason for this was the presence of sites in the protein sequence of SARS-CoV-2 that provide interaction with a broader range of receptor proteins on the host cell surface. In this review, we consider both already known receptors common to SARS-CoV and SARS-CoV-2 and new receptors specific to SARS-CoV-2.

Extracellular vesicles are lipid bilayer membrane structures without nuclei that are released from various cells as a result of physiological and metabolic changes. They play an important role in intercellular communication through the transfer of a wide range of bioactive molecules, contributing to the regulation of various physiological and pathological processes. Extracellular vesicles may have procoagulant properties due to the presence of phosphatidylserine, which accelerates coagulation reactions, on the outer layer of the membrane, as well as the expression of tissue factor, which activates coagulation along the external pathway, on the surface of some vesicles. A large number of clinical and experimental studies have shown that in various pathologies and specific physiological conditions, including pregnancy, the concentration of extracellular vesicles significantly exceeds that in healthy volunteers, which could theoretically be a factor in the development of hypercoagulable states This review focuses on describing the procoagulant properties of extracellular vesicles of various origins in normal and pathological pregnancy.

The study of the mechanisms of resistance of tumor cells to TRAIL-induced death remains an urgent task since this cytokine is an important highly selective molecular effector of antitumor immunity. Our study showed that human leukemia cells THP-1, HL-60, and K562 increased their resistance to TRAIL-induced death in vitro as a result of induction of myeloid differentiation in them by exogenous factors in all directions of myelopoiesis, except for erythroid, by reducing the expression of DR4 and DR5 receptors on the cell surface. It was also found that ONC 201, tunicamycin, and SAHA (hydroxamic acid suberoylanilide), capable of causing an increase in the expression of DR5 in leukemic cells, suppressed their TRAIL resistance induced by differentiation factors. The results obtained are of interest for the development of drugs and strategies to improve the effectiveness of the treatment of myeloid leukemia.