卷 41, 编号 3 (2024)

Tropical teleost fish Danio rerio is increasingly used as a model object for electrophysiological studies of human cardiac physiology and pathology. D. rerio is characterized by the similarity with humans in such functional parameters of the electrical activity of the heart as heart rate, action potential morphology, as well as in a set of ion currents depolarizing and repolarizing the cell membrane. D. rerio is easy to breed, easy to handle experimentally, and easy to genetically modify. This overview presents current data on the structural and functional organization of ion channels in D. rerio heart myocytes.

The effect of ionizing radiation (IR) on plants is mainly realized by altering the status of signaling systems and modifying stress signals. Variation potential (VP) is one of the types of electrical signals in plants. IR contributes to an increase in the amplitude of the VP, but the mechanisms of such influence are practically unknown. A possible way to implement changes arising from the action of IR is the regulation of gene expression. In the present work, the changes in the gene expression of participants in the generation and propagation of VP in irradiated plants are investigated. The experiments were performed on 14–15-day-old soft wheat plants (Triticum aestivum L.) grown under chronic irradiation (source ⁹⁰Sr-⁹⁰Y) with a dose rate of 31.3 μGy/h. The maximum accumulated dose was about 11.3 mGy. The irradiated plants showed no changes in the expression of calcium (TPC1), anionic (ALMT1 and CLC1), potassium (AKT1) channels, H⁺-ATPase (HA1), and NADPH oxidase (RBOHs) genes. A decrease in the expression of the SKOR potassium channel gene was revealed. The potassium channel blocker, tetraethylammonium chloride, caused an increase in response amplitude in control plants comparable to the increase in amplitude in the irradiated group. The obtained results indicate that one of the ways IR influences the electrical signals of plants is to inhibit the expression of the potassium channel.

Disulfiram (DSF) and its oxidized derivatives (DSFoxy) are currently being investigated as possible anticancer agents. We previously found that DSFoxy initiate paraptosis-like death of tumor cells, which is of potential interest for the treatment of tumors resistant to the initiation of apoptosis. Based on bioinformatics analysis of mass spectrometric data on protein ubiquitination, we formulated a conception about the important role of disruption of the retrograde transport of damaged proteins from the endoplasmic reticulum to the cytosol in the mechanism of initiation of paraptosis-like cell death. In the present work, it was found that DSFoxy, in the process of initiating paraptosis-like death of human adenocarcinoma HEp-2 cells, also enhances the ubiquitination of histones and histone code enzymes. In particular, this applies to the ubiquitination of histone H2BC12, histone methyltransferases responsible for transcription and repair of damaged DNA, as well as acetylating and ubiquitin-conjugating proteins. Bioinformatics analysis of changes in ubiquitination of cell nuclear proteins using the STRING database revealed during this process an increase in the occurrence of ubiquitinated proteins (functional enrichment) of cell cycle regulation, cell response to DNA damage and DNA repair, the regulation of which also depends on the histone code. This directly indicates damage to the cell nucleus and is consistent with confocal microscopy data. These results indicate that when paraptosis-like death is initiated by DSFoxy, along with impairment of retrograde transport and ER stress, there is also a change in the regulation of the histone code, which points to a pleotropic mechanism of cell death induction.

Hydrogen sulfide (H₂S), which, under physiological conditions, exists in cells mainly in the form of anion HS^–, is considered as a gaseous transmitter of inter- and intracellular signals along with nitrogen oxide and carbon monoxide. Analysis of the dynamics of H₂S content in living cells is impossible without creating sensitive and specific probes. Several acedan-based compounds have been synthesized in the group of K.H. Ahn (Singha et al., 2015. Anal. Chem. 87 (2), 1188–1195). In the presence of H₂S these probes attach to the sulfhydrilic group and form fluorescent carbocyclic compounds. The carbocyclic derivative of P3, compound csP3, was found to be optimal for fluorescence-microscopic studies in terms of spectral characteristics and response time to H₂S. In this work, we tested the suitability of csP3 to record H₂S changes in buffers mimicking the salt composition of the intracellular environment and in primary neuronal culture cells from rat cerebral cortex. It was found that reducing the polarity of the solution by adding dimethyl sulfoxide (30% by volume) caused a blue shift of the emission by ~10 nm and a twofold increase in fluorescence intensity. The csP3 fluorescence depends on the salt composition and increases in the presence of bicarbonate (NaHCO₃, 10 mM). Addition of P3 or csP3 to the neuronal culture caused a rapid increase in fluorescence, which was followed by a slow increase in fluorescence signal after 3–5 min. Glutamate (10 μM, in the presence of 10 μM glycine, 0 Mg²⁺) increased probe fluorescence, but only in those neurons in which delayed deregulation of calcium homeostasis did not occur. We conclude that the product of the reaction of P3 with H₂S is sensitive to a change in the salt composition of the intracellular medium and can be redistributed in cells between water and more hydrophobic environment. This means that an increase in P3 fluorescence in cells, especially after the addition of glutamate to neurons, does not necessarily indicate an increase in H₂S concentration. To confirm the feasibility of using P3 and structurally related probes as quantitative indicators of H₂S presence, additional studies of the properties of these compounds are needed.

The effect of different concentrations of copper ions (100 and 500 µM) on the fatty acid composition of the vacuolar membrane lipids of beet root tissues (Beta vulgaris L.) was studied. Exposure to 100 μM copper led to an increase in the content of FAs by 57 μg/mg of total lipids as compared to the control. Stearoyl desaturase (SDR) activity decreased from 0.87 in the control to 0.77 at 100 μM copper. Exposure to 500 μM copper caused an increase in the SDR activity up to 0.93, but the proportion of FAs decreased by 50 μg/mg of total lipids compared with 100 μM copper. In addition, there was an increase in the saturation of tonoplast lipids to 44 and 40% at 100 and 500 μM Cu²⁺, respectively. The results suggest that FAs of tonoplast lipids are involved in the stress response mechanisms induced by excessive Cu²⁺ concentrations.