Tandem Gramicidin Channels Cross-linked by Streptavidin

The interaction of biotin-binding proteins with biotinylated gramicidin (gA5XB) was studied by monitoring single-channel activity and sensitized photoinactivation kinetics. It was discovered that the addition of streptavidin or avidin to the bathing solutions of a bilayer lipid membrane (BLM) with incorporated gA5XB induced the opening of a channel characterized by approximately doubled single-channel conductance and extremely long open-state duration. We believe that the deceleration of the photoinactivation kinetics observed here with streptavidin and previously (Rokitskaya, T.I., Y.N. Antonenko, E.A. Kotova, A. Anastasiadis, and F. Separovic. 2000. Biochemistry. 39:13053–13058) with avidin reflects the formation of long-lived channels of this type. Both opening and closing of the double-conductance channels occurred via a transient sub-state of the conductance coinciding with that of the usual single-channel transition. The appearance of the double-conductance channels after the addition of streptavidin was preceded by bursts of fast fluctuations of the current with the open state duration of the individual events of 60 ms. The streptavidin-induced double-conductance channels appeared to be inherent only to the gramicidin analogue with a biotin group linked to the COOH terminus through a long linker arm. Including biotinylated phosphatidylethanolamine into the BLM prevented the formation of the double-conductance channels even with the excess streptavidin. In view of the results obtained here, it is suggested that the double-conductance channel represents a tandem of two neighboring gA5XB channels with their COOH termini being cross-linked by the bound streptavidin at both sides of the BLM. The finding that streptavidin induces the formation of the tandem gramicidin channel comprising two channels functioning in concert is considered to be relevant to the physiologically important phenomenon of ligand-induced receptor oligomerization

THE ENVIRONMENTAL ATLAS—AN IMPORTANT STAGE IN ARCTIC RESEARCH

In the present and future development of the Arctic region, much attention is and will be given to environmental problems. Along with social and economic, these issues are the most essential components of a model of sustainable development of the region. Cartographic studies implemented in the atlas format (either printed or electronic) provide the most comprehensive, adequate, and complete representation of the Arctic environment. Such Atlas will serve as a basis for creation of the Atlas Information System “Environment of the Arctic.” The material presented herein describes the purpose of the Atlas and its scientific-methodological principles. The Atlas includes 7 parts (thematic blocks) and over 18 sub-blocks that characterize natural and anthropogenic factors of formation of the natural environment, the state of the natural environment, population ecology, and efforts of Russian and international organizations aimed at optimization of the regional environment. The material also presents methodological features of the Atlas and its role in the study and management of Arctic territories

Application of Cryogenic Methods in Skin Diseases of Different Etiology

The modern demand for effective treatment options in dermatology was successfully addressed by the invention of cryogenic method. By 2009, Dr. V.I. Kochenov had developed and patented cryogenic set of instruments based on 30 years of his personal clinical experience. The set includes a number of instruments, which could be used independently. It allows implementing a wide range of therapeutic and surgical procedures and has no commercially available alternatives. The main applications of the set include cryogenic revitalization, and treatment for such common dermatological ailments as psoriasis, warts, acne, hypertrophic scars, purulent diseases of the skin and subcutaneous fat, epithelial cysts, skin hemangiomas, precancerous skin lesions, and even malignant melanoma of the skin. A brief overview of etiology, classification and pathogenesis of these maladies is presented alongside with the step-by-step guidelines to cryo-exposure procedures. Not only guidelines but also comprehensive theoretical and practical training is provided to physicians at the center which was established at Nizhny Novgorod State Medical Academy. Physicians at Scientific Clinical Center of Medical Cryology “OnKolor” have been using the set, which proved to be effective even in the most difficult and otherwise costly cases. The procedures that have pronounced cosmetic effect, leaves no scars and dark spots

Proinflammatory cytokines IL-6, IL-1β, TNF-α in infective endocarditis

Aim. To study the features of macrophages in the tissues of resected valves in operated patients with infective endocarditis (IE), their significance and interaction with inflammatory markers to improve the effectiveness of IE diagnosis. Materials and methods. Prospectively the research included 25 adult patients with active IE (Duke criteria 2015) and 24 patients with heart defects without IE, hospitalized in a cardiosurgical hospital in Moscow (2021–2022). A standard laboratory and instrumental examination was carried out for the diagnosis of IE, including etiological diagnosis with microbiological and molecular biological methods, and echocardiographic examination of heart. Additionally, the neutrophil-to-lymphocyte ratio (NLR) was calculated. The study of macrophages was carried out in the tissues of resected valves with the determination of the expression of pro- and anti-inflammatory cytokine genes, macrophage markers (CD 68+) using real-time PCR. Results. Increased expression of proinflammatory cytokines IL-1β, TNF-α and IL-6 was revealed in the group of operated patients with IE with significant differences in IL-1β (CI [IQR] 0.00367 [0.00047–0.01553] vs 0.00018 [0.00012–0.00262]; p0.05) and IL-6 (CI [IQR] 0.00367 [0.00047–0.01553] vs 0.00018 [0.00012–0.00262]; p0.05) and IL-6 (CI [IQR] 0.00338 [0.00066–0.01674] vs 0.00054 [0.00044–0.00378]; p0.05). The expression of anti-inflammatory cytokines in valve tissues prevailed in the control group without significant differences from patients with IE. The macrophage marker CD 68+ was revealed in all examined patients with a significant quantitative predominance in the group of patients with IE. There were no differences in the expression of pro- and anti-inflammatory cytokines depending on the presence of embolic events, intracardiac complications, etiological affiliation to S. aureus, as well as hospital mortality and combined endpoint (death from all causes or recurrence of IE 6 months after surgery) in patients with IE with or without events. Cytokines IL-1β and IL-6 positively correlated with each other, with leukocytes and NLR. ROC analysis determined that IL-1β and NLR had the most favorable features for the diagnosis of IE [IL-1β AUC 0.816 (p=0.02), NLR AUC 0.807 (p=0.03)]. IL-6 did not show a diagnostic value in IE. The threshold value for IL-1β was 0.00029 (sensitivity 86.4%, specificity 60.0%, prognostic value of negative result 75.0% and positive 76.0%, AUC 0.761; p=0.008). Conclusion. The valve macrophages of patients with IE express elevated levels of proinflammatory cytokines IL-1β and IL-6, regardless of etiological affiliation or complicated course of IE. IL-1β has a high diagnostic value for determining the inflammatory activity in IE

Phylogenetic analysis of variants of the Puumala virus (Hantaviridae: <i>Orthohantavirus</i>) circulating in the Saratov region

The objective is to determine the complete nucleotide sequence and conduct a phylogenetic analysis of genome variants of the Puumala virus isolated in the Saratov region. Materials and methods. The samples for the study were field material collected in the Gagarinsky (formerly Saratovsky), Engelssky, Novoburassky and Khvalynsky districts of the Saratov region in the period from 2019 to 2022. To specifically enrich the Puumala virus genome in the samples, were used PCR and developed a specific primer panel. Next, the resulting PCR products were sequenced and the fragments were assembled into one sequence for each segment of the virus genome. To construct phylogenetic trees, the maximum parsimony algorithm was used. Results. Genetic variants of the Puumala virus isolated in the Saratov region have a high degree of genome similarity to each other, which indicates their unity of origin. According to phylogenetic analysis, they all form a separate branch in the cluster formed by hantaviruses from other subjects of the Volga Federal District. The virus variants from the Republics of Udmurtia and Tatarstan, as well as from the Samara and Ulyanovsk regions, are closest to the samples from the Saratov region. Conclusion. The data obtained show the presence of a pronounced territorial confinement of strains to certain regions or areas that are the natural biotopes of their carriers. This makes it possible to fairly accurately determine the territory of possible infection of patients and/or the circulation of carriers of these virus variants based on the sequence of individual segments of their genome

Novel Photosensitizers Trigger Rapid Death of Malignant Human Cells and Rodent Tumor Transplants via Lipid Photodamage and Membrane Permeabilization

BACKGROUND: Apoptotic cascades may frequently be impaired in tumor cells; therefore, the approaches to circumvent these obstacles emerge as important therapeutic modalities. METHODOLOGY/PRINCIPAL FINDINGS: Our novel derivatives of chlorin e(6), that is, its amide (compound 2) and boronated amide (compound 5) evoked no dark toxicity and demonstrated a significantly higher photosensitizing efficacy than chlorin e(6) against transplanted aggressive tumors such as B16 melanoma and M-1 sarcoma. Compound 5 showed superior therapeutic potency. Illumination with red light of mammalian tumor cells loaded with 0.1 µM of 5 caused rapid (within the initial minutes) necrosis as determined by propidium iodide staining. The laser confocal microscopy-assisted analysis of cell death revealed the following order of events: prior to illumination, 5 accumulated in Golgi cysternae, endoplasmic reticulum and in some (but not all) lysosomes. In response to light, the reactive oxygen species burst was concomitant with the drop of mitochondrial transmembrane electric potential, the dramatic changes of mitochondrial shape and the loss of integrity of mitochondria and lysosomes. Within 3-4 min post illumination, the plasma membrane became permeable for propidium iodide. Compounds 2 and 5 were one order of magnitude more potent than chlorin e(6) in photodamage of artificial liposomes monitored in a dye release assay. The latter effect depended on the content of non-saturated lipids; in liposomes consisting of saturated lipids no photodamage was detectable. The increased therapeutic efficacy of 5 compared with 2 was attributed to a striking difference in the ability of these photosensitizers to permeate through hydrophobic membrane interior as evidenced by measurements of voltage jump-induced relaxation of transmembrane current on planar lipid bilayers. CONCLUSIONS/SIGNIFICANCE: The multimembrane photodestruction and cell necrosis induced by photoactivation of 2 and 5 are directly associated with membrane permeabilization caused by lipid photodamage

PROBLEM OF LEGAL STATUS SETTLEMENT OF REFUGEES AND DISPLACED PERSONS AFTER THE WORLD WAR II

In the history of Russia "the second wave" of Russian emigration was a unique phenomenon in its origin and political destiny. The appearance of the camps for displaced persons was another milestone in the history of the Russian emigration. In this regard, the study of the daily life of displaced persons is particularly relevant. The complexity of this issue was realized immediately after the war, in Germany there accumulated huge masses of foreigners who came voluntarily or were forcibly brought. This article describes various aspects of the legal status of refugees and displaced persons on the basis of the Charter of the International Organization for Refugees and the Charter of the IRO, as well as other international legal instruments. In addition, the authorconsiders the activities of the emigre organization - "The Society of Russian foreign lawyers in Germany", associated with the problems of regulating the legal situation of refugees and displayced persons ("DP" - «Displaced persons»), as well as other legal issues, including repatriation and immigration

ACTIVITY OF THE CATHOLIC MISSION TO ASSIST DISPLACED PERSONS IN POST-WAR PERIOD

The article discusses the activities of the Catholic missions and organizations to provide assistance to displaced persons in the post-war period. There are considered the ways of help to the Russian refugees in the camps of DP, and during their migration to other countries; as well as the issue of the Catholic priests’ influence on the Russian displaced persons and their contribution to the development of Russian abroad. The article is based on the memoirs of the contemporaries of that time, the inhabitants of the camps for DP B. Shiryaev, R. Polchaninov as well as on abbot Rostislav (Kolupaev)’s research