Fluorescence of Supported Phospholipid Bilayers Recorded in a Conventional Horizontal-Beam Spectrofluorometer

Supported phospholipid bilayers are a convenient model of cellular membranes in studies of membrane biophysics and protein-lipid interactions. Traditionally, supported lipid bilayers are formed on a flat surface of a glass slide to be observed through fluorescence microscopes. This paper describes a method to enable fluorescence detection from the supported lipid bilayers using standard horizontal-beam spectrofluorometers instead of the microscopes. In the proposed approach, the supported lipid bilayers are formed on the inner optical surfaces of the standard fluorescence microcell. To enable observation of the bilayer absorbed on the cell wall, the microcell is placed in a standard fluorometer cell holder and specifically oriented to expose the inner cell walls to both excitation and emission channels with a help of the custom cell adaptor. The signal intensity from supported bilayers doped with 1 % (mol) of rhodamine-labeled lipid in the standard 3-mm optical microcell was equivalent to fluorescence of the 70–80 nM reference solution of rhodamine recorded in a commercial microcell adaptor. Because no modifications to the instruments are required in this method, a variety of steady-state and time-domain fluorescence measurements of the supported phospholipid bilayers may be performed with the spectral resolution using standard horizontal-beam spectrofluorometers

The Ras G Domain Lacks the Intrinsic Propensity to Form Dimers

Ras GTPase is a molecular switch controlling a number of cellular pathways including growth, proliferation, differentiation, and apoptosis. Recent reports indicated that Ras undergoes dimerization at the membrane surface through protein-protein interactions. If firmly established this property of Ras would require profound reassessment of a large amount of published data and modification of the Ras signaling paradigm. One proposed mechanism of dimerization involves formation of salt bridges between the two GTPase domains (G domains) leading to formation of a compact dimer as observed in Ras crystal structures. In this work, we interrogated the intrinsic ability of Ras to self-associate in solution by creating conditions of high local concentration through irreversibly tethering the two G domains together at their unstructured C-terminal tails. We evaluated possible self-association in this inverted tandem conjugate via analysis of the time-domain fluorescence anisotropy and NMR chemical shift perturbations. We did not observe the increased rotational correlation time expected for the G domain dimer. Variation of the ionic strength (to modulate stability of the salt bridges) did not affect the rotational correlation time in the tandem further supporting independent rotational diffusion of two G domains. In a parallel line of experiments to detect and map weak self-association of the G domains, we analyzed NMR chemical shifts perturbations at a number of sites near the crystallographic dimer interface. The nearly complete lack of chemical shift perturbations in the tandem construct supported a simple model with the independent G domains repelled from each other by their overall negative charge. These results lead us to the conclusion that self-association of the G domains cannot be responsible for homodimerization of Ras reported in the literature

The experience of multiformat classes

The article describes the experience of forming a «multi-format» system of teaching the subject. The use of various forms of employment in combination with modern technologies of training gives a positive result.В статье приводится опыт формирования «мультиформатной» системы преподавания учебной дисциплины. Использование разнообразных форм проведения занятий в сочетании с современными технологиями обучения дает положительный результат

Проектно-дипломные коллективы как основа интеграции образования и научного поиска

Integration of educational process and scientific inquiry, development of creative abilities of graduates by creating graduate thesis project writing teams. Cooperative work of students and teachers of higher educational institution is presented in the article.Интеграция образовательного процесса и научного поиска, развитие творческих способностей выпускников возможно путем создания дипломно-проектных творческих коллективов. Опыт совместной работы студентов и преподавателей вуза в рамках такого коллектива излагается в статье

Abbreviations of the modern medical language used in the written press

El objetivo del presente artículo es estudiar el potencial lingüístico y creativo de unidades léxicas creadas a base de palabras o sintagmas abreviados mediante el análisis del lenguaje de la prensa escrita. El estatus lingüístico de las abreviaciones no es fijo, van acomodando su configuración externa, pronunciación y propiedades morfosintácticas a las palabras naturales del idioma. Los rasgos que testimonian la adaptación de las abreviaciones son su lexicalización y acomodación gráfica y fónica, pérdida de motivación semántica, participación activa en los procesos derivativos. La variedad en el aspecto grafemático y morfológico (oscilaciones con respecto al género, formación del plural, dificultad para distinguir las categorías gramaticales de sustantivo y adjetivo, uso de guion, mayúsculas o minúsculas) tiene relación, por un lado, con el creciente y continuado uso de las unidades abreviadas en el lenguaje y con ausencia de normas de uso convencionales, por otro. La frecuencia y amplitud de uso de las abreviaciones por razones de comodidad y economía lingüística concurre con la búsqueda de efectos estilísticos, por lo que su presencia es amplia en los llamados géneros de opinión

EBV-Positive Lymphoproliferative Diseases: A New Concept and Differential Diagnosis (Literature Review and Case Reports)

In recent years increasing attention focuses on the concept of EBV-positive lymphoproliferative diseases related to primary or secondary immunodeficiency resulting from immunosuppressive therapy and persistent infections. Due to the progress of treatment methods in oncohematology and oncology this pathology also occurs as a delayed event when new surgical and therapeutic approaches are applied. The paper presents proof for the pathogenetic significance of Epstein-Barr virus (EBV) in the pathology under consideration with its various clinical manifestations and describes the evolution of knowledge on posttransplant lymphoproliferative disorders with their morphological classification underlying EBV+ lymphoproliferative diseases. The WHO Classification of Tumours of Hematopoietic and Lymphoid Tissues revised in 2017 includes new forms of EBV+ lymphoproliferative diseases (mucocutaneous ulcer, T- and NK-cell childhood lymphoproliferative disorders including cutaneous and systemic forms of chronic active EBV infection) and EBV+ large B-cell lymphomas (unspecified and fibrin-associated diffuse large B-cell lymphomas). The paper summarizes major characteristics of these diseases and exemplifies them by the author’s own experience

Conformational States of Cytochrome P450 Oxidoreductase Evaluated by Förster Resonance Energy Transfer Using Ultrafast Transient Absorption Spectroscopy

NADPH-cytochrome P450 oxidoreductase (CYPOR) was shown to undergo large conformational rearrangements in its functional cycle. Using a new Förster resonance energy transfer (FRET) approach based on femtosecond transient absorption spectroscopy (TA), we determined the donor–acceptor distance distribution in the reduced and oxidized states of CYPOR. The unmatched time resolution of TA allowed the quantitative assessment of the donor–acceptor FRET, indicating that CYPOR assumes a closed conformation in both reduced and oxidized states in the absence of the redox partner. The described ultrafast TA measurements of FRET with readily available red–infrared fluorescent labels open new opportunities for structural studies in chromophore-rich proteins and their complexes

COGNITIVE PROBLEM IN THE MODERN STUDIES OF SOCIO-INTEGRAL PROCESSES (TO A FIRST APPROXIMATION)

Цель. Проанализировать роль, значение и направления реализации когнитивной тематики в современных науках об обществе с точки зрения эвристичности данного подхода в исследованиях проблемы социальной интеграции.Метод или методология проведения работы. При подготовке статьи были использованы сопоставительный анализ и обобщение с референцией к данным как теоретических, так и практических исследований.Результаты. В современном обществознании, включающем социологию, антропологию, экономику, социальную психологию когнитивная проблематика занимает все более значительное место, что дает возможность исследовать социальные процессы на новом теоретико-методологическом уровне и в рамках действительной полидисциплинарности. Серьезным эвристическим потенциалом обладает подход, учитывающий когнитивные факторы, и для исследования процессов социальной интеграции или конъюнкции, напрямую связанным с доминирующей в массовом сознании в конкретный исторический период поведенческой «схемой».Область применения результатов. Выводы и результаты могут быть применены для теоретического обоснования и методологического оснащения дальнейших исследований различных социальных процессов, включая социальную интеграцию. Закономерным будет и использование данных результатов в образовательной практике социально-гуманитарных направлений.Purpose. To analyze the role, significance and directions of realizing of cognitive themes in modern social sciences from the point of view of the applicability of this approach in studies of the problem of social integration.Methodology. During the preparation of the article, comparative analysis and generalization used with reference to the data of both theoretical and practical studies.Results. In modern social science, including sociology, anthropology, economics, social psychology, cognitive problems occupy an increasingly important place, which makes it possible to investigate social processes on a new theoretical and methodological level and within the framework of actual polydisciplinarity. A cognitive-based approach has an important heuristic potential for the study of processes of social integration, for those are directly related to a certain behavioral “scheme” dominant in the mass consciousness in a given historical period.Practical implications. Conclusions and results could be applied to the theoretical substantiation and methodological equipment of further studies of various social processes, including social integration. It will be natural to use these results in the educational practice of social and humanitarian areas

Analysis of Binding Site Hot Spots on the Surface of Ras GTPase

We have recently discovered an allosteric switch in Ras, bringing an additional level of complexity to this GTPase whose mutants are involved in nearly 30% of cancers. Upon activation of the allosteric switch, there is a shift in helix 3/loop 7 associated with a disorder to order transition in the active site. Here, we use a combination of multiple solvent crystal structures and computational solvent mapping (FTMap) to determine binding site hot spots in the “off” and “on” allosteric states of the GTP-bound form of H-Ras. Thirteen sites are revealed, expanding possible target sites for ligand binding well beyond the active site. Comparison of FTMaps for the H and K isoforms reveals essentially identical hot spots. Furthermore, using NMR measurements of spin relaxation, we determined that K-Ras exhibits global conformational dynamics very similar to those we previously reported for H-Ras. We thus hypothesize that the global conformational rearrangement serves as a mechanism for allosteric coupling between the effector interface and remote hot spots in all Ras isoforms. At least with respect to the binding sites involving the G domain, H-Ras is an excellent model for K-Ras and probably N-Ras as well. Ras has so far been elusive as a target for drug design. The present work identifies various unexplored hot spots throughout the entire surface of Ras, extending the focus from the disordered active site to well-ordered locations that should be easier to target

Успешная последовательная иммуноэпигенетическая терапия эритродермической формы грибовидного микоза

Mucosis fungoidea (МF) belongs to the class of epidermotropic T-cell lymphomas. MF is represented by over 10 sub-types only in terms of its clinical manifestations, with one of them being erythrodermic MF (EMF). This disease is characterized by diverse symptomatology in the form of erythroderma and intense skin itch, aggressive сlinical course and unfavorable prognosis. The disease prognosis also correlates with age, previous history of long-term systemic gluco-corticosteroid treatment (GCS), increased activity of lactate dehydrogenase (LDH) and hypereosinophilia. The choice of MF treatment is determined by the disease stage and somatic status of the patient. In EMF, a therapy combining various effective preparations and taking into account the specifics of the given case is required. Extracorporeal photopheresis (ECP) is frequently an approach of choice; however, it has demonstrated the highest efficacy in Sezary disease or in EFM associated with leucemization. Application of new pharmaceuticals (monoclonal antibodies, epigenetic agents) in combination or in sequence with immune therapy is a promising direction, particularly for treating patients older than 75 years. In this paper, we describe the clinical case of an elderly patient suffering from EMF without peripheral blood leukemia with multimodal factors of unfavorable prognosis, such as age, increased lactate dehy drogenase activity, history of prolonged inefficient treatment with gluco-cortecosteroid preparations and eosinophilia. A long-term positive response to the treatment using sequential immune epigenetic therapy has not been achieved, although the treatment tolerability and the patient's life quality were satisfactory.Грибовидный микоз (ГМ) относится к эпидермотропным Т-клеточным лимфомам и по своему только клиническому проявлению и течению представлен более чем 10 подтипами, одним из которых является эритродермическая форма ГМ (эГМ). Данный вариант болезни имеет развернутую симптоматику в виде эритродермии и наличия интенсивного кожного зуда, агрессивный характер течения и неблагоприятный прогноз. Прогноз также коррелирует с возрастом, предшествующим анамнезом длительного приема системных глюкокортикостероидных препаратов (ГКС), повышенной активностью лактатдегидрогеназы (ЛДГ) и гиперэозинофилией. Лечение ГМ определяется стадией, соматическим статусом пациента, и, как правило, при эГМ необходимо сочетанное применение потенциально эффективных препаратов, основываясь на пациент-индивидуализированном подходе. Экстракорпоральный фотоферез (ЭКФ) является одним из рекомендуемых методов лечения, однако наилучшие результаты демонстрирует при синдроме Сезари или эГМ с лейкемизацией. Применение новых препаратов (моноклональные антитела, эпигенетические агенты) в сочетании или последовательно с иммунотерапией является перспективным изучаемым направлением, открывающим возможность успешного лечения, в том числе для пациентов старше 75 лет. В приведенном клиническом случае у пожилого пациента с эритродермическим вариантом грибовидного микоза без лейкемического состава периферической крови с мультимодальными факторами неблагоприятного прогноза, такими как возраст, повышенная активность ЛДГ, анамнез длительного неэффективного приема ГКС и эозинофилия, полного продолжительного ответа удалось достичь в результате последовательной иммуноэпигенетической терапии при удовлетворительной переносимости лечения и сохранения хорошего качества жизни больного