Prediction and observation of an antiferromagnetic topological insulator.

Magnetic topological insulators are narrow-gap semiconductor materials that combine non-trivial band topology and magnetic order1. Unlike their nonmagnetic counterparts, magnetic topological insulators may have some of the surfaces gapped, which enables a number of exotic phenomena that have potential applications in spintronics1, such as the quantum anomalous Hall effect2 and chiral Majorana fermions3. So far, magnetic topological insulators have only been created by means of doping nonmagnetic topological insulators with 3d transition-metal elements; however, such an approach leads to strongly inhomogeneous magnetic4 and electronic5 properties of these materials, restricting the observation of important effects to very low temperatures2,3. An intrinsic magnetic topological insulator-a stoichiometric well ordered magnetic compound-could be an ideal solution to these problems, but no such material has been observed so far. Here we predict by ab initio calculations and further confirm using various experimental techniques the realization of an antiferromagnetic topological insulator in the layered van der Waals compound MnBi2Te4. The antiferromagnetic ordering  that MnBi2Te4  shows makes it invariant with respect to the combination of the time-reversal and primitive-lattice translation symmetries, giving rise to a ℤ2 topological classification; ℤ2 = 1 for MnBi2Te4, confirming its topologically nontrivial nature. Our experiments indicate that the symmetry-breaking (0001) surface of MnBi2Te4 exhibits a large bandgap in the topological surface state. We expect this property to eventually enable the observation of a number of fundamental phenomena, among them quantized magnetoelectric coupling6-8 and axion electrodynamics9,10. Other exotic phenomena could become accessible at much higher temperatures than those reached so far, such as the quantum anomalous Hall effect2 and chiral Majorana fermions3.

Endogenous Brassinosteroids Are Involved in the Formation of Salt Resistance in Plants.

The endogenous brassinosteroid (BS) profile was for the first time shown to change in response to salt stress in potato plants. A group of 6-keto-BSs was identified and found to significantly increase in content during salinization in contrast to other groups of hormones examined. A tenfold reduction in the level of endogenous BSs in mutant Arabidopsis thaliana plants with impaired biosynthesis (det2) (or reception (bri1)) of phytosteroids decreased their salt resistance, as evidenced by a lower efficiency of photochemical processes of photosystem II (PSII) and growth inhibition. The results confirmed the idea that endogenous BSs are involved in the formation of salt resistance in plants.

Silatrane-Sulfonamide Hybrids as Promising Antibacterial Agents.

At the A. E. Favorsky Irkutsk Institute of Chemistry, a series of silatrane-sulfonamide hybrids 1a-d and 2a-d was synthesized. The antibacterial activity of 1a, 1b, 1d, 2a, and 2b against test strains of bacteria Yersinia pestis EV NIIEG, Yersinia enterocolitica 628/1, Listeria monocytogenes 766, and Starhylococcus aureus ATCC 6538-P (FDA 209-Р) was evaluated. The minimum inhibitory concentration for silatrane-sulfonamide hybrids was 100-200 mg/liter. Silatrane-sulfonamide hybrid 1d was the most active against all tested strains: minimum inhibitory concentration 100 mg/liter. Exposure to silatrane-sulfonamide hybrids in a doses of 100-200 mg/liter inhibited culture growth by 50-75%.

Development of a Test System to Detect the Omicron Variant of SARS-CoV-2 and the Frequency of Its Detection in Patients.

We developed a new test system to detect the omicron variant of SARS-CoV-2 using allele-specific reverse transcription PCR and estimated the frequency of its detection in patients living in the Novosibirsk Region. Clinical samples were divided into 3 groups: samples collected from December 1 to December 30, 2021 (group 1; n=66), from December 30, 2021 to January 10, 2022 (group 2; n=20), and from January 11 to January 22, 2022 (group 3; n=101). Based on the identification of 5 mutations specific to SARS-CoV-2 (B.1.1.529), two systems of oligonucleotide primers and probes were developed for detecting this coronavirus genotype in clinical samples. Limit of detection (LOD95) was 4×103 genome equivalents per 1 ml of clinical sample for the first test system and 2×103 for the for the second test system. The omicron variant of SARS-CoV-2 was absent in group 1 of studied samples, but was detected in 20% (4/20) of group 2 samples and 88% of group 2 samples collected within less than 2 weeks of January 2022. Using developed test system, we showed that in less than 2 weeks the omicron variant has become dominant in patients, which confirms previously published data on its exceptional contagiousness.

Comparison of Protective Reactions of Rape Seeds to Chloride Salination at Exposure to Epibrassinolide before or during Salt Stress.

We compared the defensive response of rape plants to treatment with 24-epibrassinoldide (10 nM, EBL) before the onset of salt stress (preadaptation stage) and under conditions of chloride salination (150 mM NaCl). It is shown that salt stress inhibits some growth parameters by 30-35%. EBL, regardless of the plant treatment method, showed a pronounced protective effect, first of all, at the level of the assimilating surface, the main photosynthetic pigments, and the photochemical activity of photosystem II. It was established for the first time that the pretreatment of plants with EBL followed by salt stress is accompanied by suppression of NaCl-induced accumulation of proline and an increase in superoxide dismutase activity, whereas the addition of a hormone under salt stress increases the content of carotenoids, which leads to a decrease in the level of lipid peroxidation.

Polymetallic Stress Changes the Endogenous Status of Brassinosteroids and Reduces the Effectiveness of Photochemical Reactions Photosystem II in Barley Plants.

The effect of polymetallic stress (Mn2+, Cd2+, Cu2+, Ni2+, Zn2+, Pb2+, and Al3+) of different duration and intensity on the endogenous brassinosteroids (BS) content and photochemical activity of photosystem II in barley plants was studied. The content of steroid hormones was determined by a two-stage enzyme immunoassay. It was established for the first time that barley plants responded to polymetallic stress by changing the endogenous content of various phytosteroid groups (24S-methylBS, 24-epiBS, 28-homoBS, B-lactoneBS, and 6-ketoBS). It was shown that the stress-dependent dynamics of changes in the endogenous content of various BS groups is characterized by organ specificity and is determined by the age of plants, the intensity of the acting stressor, and the specificity of brassinosteroids. The observed changes in the endogenous status of BS in barley plants under polymetallic stress are accompanied by inhibition of growth processes, a decrease in the content of the main photosynthetic pigments, and a slight decrease in the efficiency of photochemical processes in PS II (Fv/Fm, ETR, qN, and NPQ). Considering the multifunctional stress-protective effect of brassinosteroids, it is assumed that the change in the endogenous status of BS against the background of polymetallic pollution is adaptive and allows minimizing the damaging effects of toxic heavy metals and aluminum.

[Testosterone and congestive heart failure].

This article summarizes current information about the interrelation between testosterone concentrations and chronic heart failure (CHF). The authors described key publications that address the prevalence of testosterone deficiency in patients with CHF, the effect of endogenous and exogenous testosterone on the cardiovascular system, the relationship between testosterone levels and the severity and prognosis of CHF, and the efficacy of interventional treatments for CHF.

Exogenic Melatonin Reduces the Toxic Effect of Polymetallic Stress on Barley Plants.

The effect of melatonin on growth parameters, the photochemical activity of photosystem II (PS II), the content of the main photosynthetic pigments, and lipid peroxidation in barley plant leaves under polymetallic stress were studied. Melatonin reduces the toxic effect of polymetals on biomass accumulation, root growth, and maintenance of the assimilating surface. The protective action of the hormone is based on its ability to reduce the intensity of oxidative stress by maintaining the level of carotenoids and increasing the activity of superoxide dismutase, but not by regulating the photochemical activity of chloroplasts. The effectiveness of melatonin does not depend on the duration of exposure. The data obtained can be the basis for optimizing the use of melatonin as a plant priming inducer.

The Influence of Comorbid Endemic Goiter on the Quality of Life of Patients with Gastrointestinal Pathology.

The impairment of adaptive mechanisms of functional systems of the body plays an important role in the occurrence of gastrointestinal diseases. This impairment is caused by unfavorable ecological and radiation conditions, external stress factors, food containing carcinogens, macro - and microelements deficiency. Technogenic environmental pollution contributes to decrease in the level of iodine in the body and more severe course of thyroid pathology. Diseases of the digestive and endocrine systems and their combination will occupy one of the leading places among the existing pathologies according to the forecasts of WHO experts in the XXI century. Adaptation of the body to various environmental influences is the most important factor in the quality of life. The relevance of the study was determined by the high incidence of psychological disadaptation, borderline personality disorders and, as a consequence, decrease in the quality of life in patients with gastrointestinal pathology and hypothyroidism. The article presents the results of comparative analysis of the quality of life indications of patients with gastric ulcer and / or gastroesophageal reflux disease in combination with hypothyroidism. The Russian-language analogue of the international questionnaire SF36 was used to analyze the indicatoions of patients' quality of life. The results of the study will allow to formulate the diagnosis exactly and organize adequate, comprehensive multidisciplinary treatment.

The risk score for in-hospital mortality in patients with ST-segment elevation myocardial infarction.

Aim    To develop a scale (score system) for predicting the individual risk of in-hospital death in patients with ST segment elevation acute myocardial infarction (STEMI) with an account of results of percutaneous coronary intervention (PCI).Material and methods    The analysis used data of 1 649 sequential patients with STEMI included into the hospital registry of PCI from 2006 through 2017. To test the model predictability, the original sample was divided into two groups: a training group consisting of 1150 (70 %) patients and a test group consisting of 499 (30 %) patients. The training sample was used for computing an individual score. To this purpose, ß-coefficients of each variable obtained at the last stage of the multivariate logistic regression model were subjected to linear transformation. The scale was verified using the test sample.Results    Seven independent predictors of in-hospital death were determined: age ≥65 years, acute heart failure (Killip class III-IV), total myocardial ischemia time ≥180 min, anterior localization of myocardial infarction, failure of PCI, SYNTAX scale score ≥16, glycemia on admission ≥7.78 mmol/l for patients without a history of diabetes mellitus and ≥14.35 mmol/l for patients with a history of diabetes mellitus. The contribution of each value to the risk of in-hospital death was ranked from 0 to 7. A threshold total score of 10 was determined; a score ≥10 corresponded to a high probability of in-hospital death (18.2 %). In the training sample, the sensitivity was 81 %, the specificity was 80.6 %, and the area under the curve (AUC) was 0.902. In the test sample, the sensitivity was 96.2 %, the specificity was 83.3 %, and the AUC was 0.924.Conclusion    The developed scale has a good predictive accuracy in identifying patients with acute STEMI who have a high risk of fatal outcome at the hospital stage.

Influence of Total Ischemic Time on Clinical Outcomes in Patients with ST-Segment Elevation Myocardial Infarction.

Aim      To evaluate the effect of the total time of myocardial ischemia on results of the treatment of patients with ST segment elevation acute myocardial infarction (STEMI) who underwent percutaneous coronary interventions (PCI).Material and methods This study used data from a hospital register for PCI in STEMI from 2006 through 2017. 1649 patients were included. Group 1 consisted of 604 (36.6 %) patients with a total time of myocardial ischemia not exceeding 1880 min; group 2 included 531 (32.2 %) patients with a duration of myocardial ischemia from 180 to 360 min; and group 3 included 514 (31.2 %) patients with a duration of myocardial ischemia longer than 360 min.Results Mortality was lower in group 1 (2.3 %) than in groups 2 and 3 (6.2 and 7.2 %, respectively; p1-2=0.001; p1-3<0.001; p2-3=0.520). The incidence of major cardiac complications ("adverse cardiac events", MACE) was lower in group 1 (4.1 %) than in groups 2 and 3 (7.3 and 9.5 %, respectively, p1-2=0.020; p1-3<0.001; p2-3=0.200). The incidence of no-reflow phenomenon was higher in group 3 (9.7 %) than in groups 2 and 3 (4.5 and 5.3 %, respectively (p1-2=0.539; p1-3=0.001; p2-3=0.005). The major factors associated with the increased total time of myocardial ischemia >180 min were age (odd ratio, OR, 1.01 at 95 % confidence interval, CI, 1.0 to 1.02; р=0.044), female gender (OR, 1.64 at 95 % CI 1.26 to 2.13; р<0.001), chronic kidney disease (OR 1.82 at 95 % CI 1.21 to 2.74; р=0.004). Performing prehospital thrombolysis was associated with a decrease in the total time of myocardial ischemia (OR 0.4 at 95 % CI 0.31 to 0.51; р<0.001). A strong direct correlation was observed between the total time of myocardial ischemia and the time from the onset of pain syndrome to hospitalization (r=0.759; р<0.001).Conclusion      The total time of myocardial ischemia >180 min was associated with increased mortality and development of MACE. The total time of myocardial ischemia > 360 min was associated with increased incidence of the no-reflow phenomenon. The major predictors for the time of myocardial ischemia >180 min included age, female gender, and chronic kidney disease. The use of pharmacoinvasive strategy was associated with an increased number of patients with a total duration of myocardial ischemia <180 min. The contribution of the time of prehospital delay to the total time of myocardial ischemia was greater than the contribution of the "door-to-balloon" time. The time of prehospital delay showed a strong direct correlation with the total time of myocardial ischemia.

[Assessment of no-reflow phenomenon in patients with acute ST-elevation myocardial infarction]. / Otsenka fenomena 'no-reflow' u patsientov s ostrym infarktom miokarda s pod''emom segmenta ST.

BACKGROUND: The problems concerning assessment of the state of myocardial perfusion in patients with acute ST elevation myocardial infarction after successful revascularization still remain of current importance. Contrast-enhanced echocardiography remains the least studied and most promising ultrasound technology for the diagnosis of the no-reflow phenomenon. AIM: The study was aimed at evaluating echocardiographic and angiographic characteristics of the no-reflow phenomenon detected by means of contrast-enhanced echocardiography in patients with ST-segment elevation myocardial infarction. PATIENTS AND METHODS: The study included a total of forty-three 40-to-82-year-old patients in acute period of myocardial infarction. The patients were divided into two groups: 32 patients with satisfactory myocardial reperfusion after revascularization according to the findings of contrast-enhanced echocardiography and 11 patients with impaired perfusion. RESULTS: The patients in the group with impaired perfusion demonstrated a greater size of the left ventricular (LV) asynergy (40.1±2.2% vs 27.4±8.5%, p<0.001), more frequent LV dilatation (LV end-systolic volume 67.3±20.3 ml vs 51.8±17.2 ml, p=0.015), decreased LV contractility (LV ejection fraction 39.5±3.4% vs 47.2±4.9%, p < 0.001), and significant mitral regurgitation (45.5% vs 3.1%, p=0.011) with a decrease in DP/DT (979.9±363.4 mmHg/s vs 1565.7±502.8 mmHg/s, p<0.001) were more often detected in this group. Coronary angiography showed no perfusion disorders after revascularization in more than a quarter of these patients. In the group with impaired perfusion, more frequently revealed were single-vascular lesions (46.9% vs 9.1%, p=0.033), lesions of the anterior interventricular artery (90.9% vs 40.6%, p=0.004), and acute occlusion (100% vs 68.8%, p=0.043); compliance by the SYNTAX score in this group was higher (18.9±3.7 vs 9.9±5.7, p<0.001). CONCLUSION: In patients with acute myocardial infarction after successfully performed revascularization, perfusion disorders revealed by the findings of contrast-enhanced echocardiography were accompanied by more pronounced echo signs of left-ventricular dysfunction, higher values of the SYNTAX score and significantly more frequently revealed lesions of the anterior interventricular septum as compared with the patients with recovered perfusion.

Fuels, power and chemical periodicity.

The insatiable-and ever-growing-demand of both the developed and the developing countries for power continues to be met largely by the carbonaceous fuels comprising coal, and the hydrocarbons natural gas and liquid petroleum. We review the properties of the chemical elements, overlaid with trends in the periodic table, which can help explain the historical-and present-dominance of hydrocarbons as fuels for power generation. However, the continued use of hydrocarbons as fuel/power sources to meet our economic and social needs is now recognized as a major driver of dangerous global environmental changes, including climate change, acid deposition, urban smog and the release of many toxic materials. This has resulted in an unprecedented interest in and focus on alternative, renewable or sustainable energy sources. A major area of interest to emerge is in hydrogen energy as a sustainable vector for our future energy needs. In that vision, the issue of hydrogen storage is now a key challenge in support of hydrogen-fuelled transportation using fuel cells. The chemistry of hydrogen is itself beautifully diverse through a variety of different types of chemical interactions and bonds forming compounds with most other elements in the periodic table. In terms of their hydrogen storage and production properties, we outline various relationships among hydride compounds and materials of the chemical elements to provide some qualitative and quantitative insights. These encompass thermodynamic and polarizing strength properties to provide such background information. We provide an overview of the fundamental nature of hydrides particularly in relation to the key operating parameters of hydrogen gravimetric storage density and the desorption/operating temperature at which the requisite amount of hydrogen is released for use in the fuel cell. While we await the global transition to a completely renewable and sustainable future, it is also necessary to seek CO2 mitigation technologies applied to the use of fossil fuels. We review recent advances in the strategy of using hydrocarbon fossil fuels themselves as compounds for the high capacity storage and production of hydrogen without any CO2 emissions. Based on these advances, the world may end up with a hydrogen economy completely different from the one it had expected to develop; remarkably, with 'Green hydrogen' being derived directly from the hydrogen-stripping of fossil fuels. This article is part of the theme issue 'Mendeleev and the periodic table'.

Melatonin Supports Photochemical Activity of Assimilation Apparatus and Delays Senescence of Leaves of Monocotyledonous Plants.

Melatonin supports the photochemical activity of photosystem II (PS II) and slows down the degradation of the main photosynthetic pigments during aging of leaves of monocotyledonous plants. The protective effect of melatonin is manifested in an increase in the maximum (Fv/Fm) and effective (Y(II)) quantum yield of PS II, in an increase of regulated (Y(NPQ)) and a decrease in unregulated dissipation of excitation energy (Y(NO)). These effects are based on the ability of melatonin to reduce the intensity of oxidative stress by maintaining a high level of carotenoids, which exhibit pronounced antioxidant properties, during aging.

The Multidimensional Scale of Perceived Social Support (MSPSS): Reliability and Validity of Russian Version.

Objective: To assess factorial and construct validity along with reliability of the Russian version of the Multidimensional Scale of Perceived Social Support (MSPSS) in cardiac patients.Methods: The study included 1018 patients with coronary artery disease. All patients were offered the opportunity to complete a questionnaire to detect psychosocial risk and protective factors, including the MSPSS.Results: Internal consistency of the Russian version of the MSPSS was high: Cronbach's alpha coefficient in the group of patients with stable angina was .91 vs. .90 in the group with acute coronary syndrome. The three-factor structure of the MSPSS was proved with exploratory and confirmatory factor analyses. As expected, the Russian version of the MSPSS was negatively correlated with measures of anxiety and depression, and positively correlated with curiosity.Conclusions: The Russian version of MSPSS corresponds closely with the English version in reliability, consistency, and internal structure. Test-retest reliability was satisfactorally high and construct validity was supported with the results of the correlation analysis.Clinical Implications: Our study confirms that MSPSS questionnaire is a high valid tool to estimate social support and it can be successfully applied to define social support in patients with cardiac pathology.

[Association of left bundle branch block definitions with response to cardiac resynchronisation therapy in patients with congestive heart failure].

Aim To compare diagnostic significance of different criteria for complete left bundle branch block (cLBBB) in prediction of reverse left ventricular (LV) remodeling associated with cardiac resynchronization therapy (CRT).Materials and methods This study included 93 patients (men, 81.7 %; mean age at the time of implantation, 56.6±9.3 years). Achievement of a maximum decrease in LV end-systolic volume (ESV) was recorded during the entire follow-up period for evaluation of LV reversibility by CRT. Based on the dynamics of LV ESV, patients were divided into two groups, non-responders (n=27) and responders (n=66). cLBBB was determined by 9 criteria (ESC 2006 and 2013, AHA 2009, Strauss, and MIRACLE, CARE-HF, MADIT-CRT, REVERSE, and RAFT used in large multicenter studies).Results Incidence of cLBBB was significantly higher in the group of responders as demonstrated by the AHA (p=0.001), ESC 2013 (p=0.014), Strauss (p=0.002), MADIT-CRT (p=0.014), REVERSE (p=0.013), and RAFT (p<0.001) criteria. The highest specificity was shown for the AHA and RAFT (92.6 %) criteria, and the highest sensitivity and overall accuracy were shown for the Strauss (80.3 % and 72.04 %, respectively) criterium. The criteria proposed in actual clinical guidelines (AHA and ESC 2013) demonstrated a strong consistency in detecting cLBBB (κ=0.818, 95 % CI, 0.7-0.936; p<0.001). However, the Strauss and ESC 2006 / AHA / ESC 2013 showed the least consistency in identifying cLBBB. For the criteria described in large multicenter studies, consistency in detecting cLBBB was minimal in most cases. However, criteria with moderate or strong consistency were used in the studies, which results have substantiated the use of cLBBB as a selection criterium (MADIT-CRT, REVERSE, and RAFT).Conclusion The reversibility of LV remodeling associated with CRT was different in patients with cLBBB determined by different criteria. All actual cLBBB criteria (AHA, ESC 2013, and Strauss) were significantly more frequently observed in the responder group. Nevertheless, these criteria differed in their sensitivity and specificity. A number of large multicenter studies have used criteria with minimal consistency in detecting cLBBB, which should be taken into account in interpreting results of these studies.

[Percutaneous Coronary Interventions in Patients With ST-Elevation Myocardial Infarction: 10-Years Follow-up].

Aim      To study long-term results and to identify predictors of death in patients with ST-segment elevation acute myocardial infarction (STEMI) who underwent endovascular revascularization.Materials and methods This study included 283 patients registered in the hospital registry of percutaneous coronary interventions (PCI) for STEMI from 2006 through 2009. Analysis of 10-year results included all-cause and cardiovascular death rate, incidence of recurrent myocardial infarction (MI), repeated revascularization, stroke, stent restenosis and thrombosis. Also, a composite endpoint МАССЕ (Major Adverse Cardiovascular and Cerebrovascular Events) was evaluated, which included death, recurrent MI, repeated PCI, stent restenosis and thrombosis, coronary bypass, and stroke.Results Information about the health condition was provided by 204 (72.1 %) patients. Mean follow-up period was 120.1±9.5 months. All-cause mortality was 25.5 % with cardiovascular death determined in 19.1 % of cases. Recurrent MI developed in 21.6 % of patients; in 1.5 % of cases, recurrent MI resulted from thrombosis of previously implanted stents. Repeated PCI was performed for 31.9 % of patients; in 13.7 % of cases, the PCI was performed for stent restenosis. Coronary bypass was performed for 5.4 % of patients. Incidence of stroke was 10.3 %. Major cardiovascular and cerebrovascular complications (МАССЕ) during the follow-up period were determined in 60.3 % patients. According to the Cox proportional hazards regression model, age ≥65 years (odds ratio (OR), 3.75 at 95 % confidence interval (CI) from 1.75 to 8.03; р=0.001) and incomplete coronary revascularization (OR, 3.09 at 95 % CI from 1.52 to 6.30; р=0.002) were independent predictors of death based on data of the 10-year observation.Conclusion      Therefore, at 10 years following endovascular revascularization, STEMI patients showed a moderate death rate with a high incidence of major cardiovascular and cerebrovascular complications. The leading causes for fatal outcomes were recurrent cardiovascular complications. The major predictors of death for the coming 10-year period included age ≥65 years and incomplete myocardial revascularization.

Tolerance of Potato Plants to Chloride Salinity Is Regulated by Selective Light.

Potato plant tolerance to chloride salinity rose after short-term exposure to blue light, which has been first shown in this study. The protective effect of blue light was based on its ability to stimulate the accumulation of low-molecular weight organic compounds with antioxidant activity.

Jasmonic Acid Enhances the Potato Plant Resistance to the Salt Stress in Vitro.

The protective effect of jasmonic acid (JA) was evaluated under the stress conditions (100 mM NaCl). The potato plants Solanum tuberosum L, mid-season variety Lugovskoy, were used in the experiments. The plant-regenerants were grafted and grown in test tubes on the modified Murashige and Skoog agar medium in the absence (control) or presence of JA at concentrations of 0.001, 0.1, and 10 µM under the optimal conditions or with addition of NaCl. After 28 days of cultivation, the growth (stem and root lengths, tier and leaf numbers, and plant mass) and physiological (proline and photosynthetic pigment contents and teh osmotic potential of cell exudate) characteristics of the plants were assessed. Jasmonic acid (0.1 and 10 µM) has been demonstrated to display a pronounced protective effect on potato plants under the salt stress condition. JA abolished partially the negative salt effect on the main photosynthetic pigments and maintained the cell osmotic status during salinization.

The Endogenous Brassinosteroid Content and Balance in Potato Microclones Is Determined by Organ Specificity and the Variety Ripening Term.

The brassinosteroid (BS) profiles in shoots and roots of the potato plants were shown to be organ-specific and dependent on the term of variety ripening. The amount of all studied groups of steroid phytohormones proved to be an order of magnitude higher in roots than in shoots. In roots, the brassinosteroid lactones predominated, while in shoots, their biogenetic precursors, 6-ketones, were prevailing. The early-ripening variety Zhukovsky Early is characterized by a high content of almost all BS groups (first of all, brassinolide group) and a relatively high content of B-lactones in shoots. With aging, the content of B-lactones in plants decreases, while that of B-ketones grows up.