How to change the oligomeric state of a circular protein assembly: switch from 11-subunit to 12-subunit TRAP suggests a general mechanism

Many critical cellular functions are performed by multisubunit circular protein oligomers whose internal geometry has evolved to meet functional requirements. The subunit number is arguably the most critical parameter of a circular protein assembly, affecting the internal and external diameters of the assembly and often impacting on the protein's function. Although accurate structural information has been obtained for several circular proteins, a lack of accurate information on alternative oligomeric states has prevented engineering such transitions. In this study we used the bacterial transcription regulator TRAP as a model system to investigate the features that define the oligomeric state of a circular protein and to question how the subunit number could be manipulated.We find that while Bacillus subtilis and Bacillus stearothermophilus TRAP form 11-subunit oligomers, the Bacillus halodurans TRAP exclusively forms 12-subunit assemblies. Significantly, the two states of TRAP are related by a simple rigid body rotation of individual subunits around inter-subunit axes. We tested if such a rotation could be induced by insertion or deletion mutations at the subunit interface. Using wild type 11-subunit TRAP, we demonstrate that removal of five C-terminal residues at the outer side of the inter-subunit axis or extension of an amino acid side chain at the opposite, inner side, increased the subunit number from 11 to 12. Our findings are supported by crystal structures of TRAP oligomers and by native mass spectrometry data.The subunit number of the TRAP oligomer can be manipulated by introducing deletion or addition mutations at the subunit interface. An analysis of available and emerging structural data on alternative oligomeric states indicates that the same principles may also apply to the subunit number of other circular assemblies suggesting that the deletion/addition approach could be used generally to engineer transitions between different oligomeric states

ABOUT THE FACTORS AND REASONS OF UNIVERSITY STUDENT EXPULSIONS AND STUDENT MOTIVATION FOR EDUCATIONAL ACTIVITIES

Introduction. The conclusion of the “effective contract” with teachers has recently become one of the innovations at the higher school. According to the drafters of this document, it has to take the position of the economic instrument for increasing the labour productivity of educators and stimulating them to the effective result-oriented activity. However, some qualitative and quantitative indicators of the contract which form the basis of the fixed amount of financial award of teachers lead to confusion. In particular, the number of the students expelled from higher education institution belongs to such indicators. Aim. Based on the factual material, statistical data and mathematical calculations, the aim of the publication is to prove the absence of direct relationship between the number of the expelled students and the quality of professional activity of the university teacher. Methodology and research methods. In the course of the research, the review and synthesis of the scientific publications on the discussed problems were used; poll and questioning of students were conducted by means of the T. I. Ilyina’s technique “Motivation for Training in Higher Education Institution”. The obtained data was processed by the method of the correlation analysis; degree of statistical reliability of results was estimated by means of calculation of F-criterion. Results and scientific novelty. The survey was conducted among full-time students of different years of studies enrolled on the five-year specialty training programme “Train Traffic Management Systems” of the Far Eastern State Railway Communications University. The survey made it possible to identify the common factors and reasons of expulsion from higher education institution among students of all years of studies. Statistical data on motivation of students for training are collected and analysed. Correlations between indicators of expulsion and motives to get higher education are established. The authors provided a reasoned justification for obvious absurdity of the issue about accounting the student contingent retention as criterion of the teacher quality of work. Student expulsion is the indicator that reflects a condition of all education system and includes the following: school, institute of the Unified State Examination (USE), selection criteria in higher education institution, standard legislative base in education, curricula, logistics and equipment, conditions of educational activity, etc., as well as student motivation for training. Therefore, the ordinary teacher can not and must not be responsible for student expulsions.Practical significance. The authors conclude that the “effective contract” as it drafted encourages not teachers, but a high number of uneducated “professionals” who graduate from higher education institutions, including those who study free of charge. Artificial support of student membership completely contradicts state policy on human resource development of the country; furthermore, it poses threat of destruction both for the system of the higher education, and for national economy in general. It is obviously required to develop other more reasonable approaches that are adequate to the higher school tasks and to the choice of quality criteria for activity of higher education institutions and their employees.Введение. Одним из нововведений последнего времени в высшей школе стало внедрение в практику заключения «эффективного контракта» с преподавателями, который, по мнению его разработчиков, должен стать экономическим инструментом повышения производительности труда работников сферы образования, стимулирующим их к эффективной деятельности, нацеленной на результат. Однако некоторые качественные и количественные показатели контракта, на основании которых определяется размер финансового поощрения педагогов, вызывают недоумение. К таким показателям относится, в частности, количество отчисленных из вуза студентов.Цель публикации – доказать с опорой на фактический материал, статистические данные и математические расчеты отсутствие прямой связи между количеством отчисляющихся обучающихся и качеством профессиональной деятельности преподавателя вуза. Методы и методики. В процессе исследования использовались обзор и обобщение содержания научных источников, касающихся обсуждаемых проблем; опрос и анкетирование студентов с помощью методики «Мотивация обучения в вузе» Т. И. Ильиной. Обработка полученных данных производилась методом корреляционного анализа; степень статистической достоверности результатов оценивалась посредством вычисления F-критерия Фишера. Результаты и научная новизна. На выборках студентов специальности «Системы обеспечения движения поездов», обучающихся очно в Дальневосточном государственном университете путей сообщения по пятилетней программе специалитета, выявлены закономерности и причины их отчислений из вуза на всех курсах профессиональной подготовки. Собраны и проанализированы статистические данные о мотивированности студентов к обучению. Установлены корреляции между показателями отчислений и мотивами получения высшего образования. Аргументированно обоснована абсурдность учета сохранности студенческого контингента в качестве критерия качества работы преподавателя. Отчисление студента – это показатель, отражающий состояние всей системы образования, включая школу, институт ЕГЭ, критерии отбора в вуз, нормативно-законодательную базу в сфере образования, учебные планы, материально-техническую обеспеченность, условия учебной деятельности и т. д., а также мотивацию к обучению самого студента. Поэтому рядовой преподаватель не может и не должен нести индивидуальную ответственность за отчисление студента. Практическая значимость. Сделан вывод о том, что «эффективный контракт» в существующем виде поощряет не педагогов, а выпуск из вузов необразованных «профессионалов», в том числе за бюджетные средства. Искусственная поддержка численного состава студентов противоречит государственной политике развития кадрового потенциала страны и несет угрозу разрушения как для системы высшего образования, так и для экономики страны в целом. Очевидно, что требуется выработать иные, более разумные и адекватные задачам высшей школы подходы к выбору критериев качества деятельности вузов и их сотрудников

New Method of Vaccination Against Anthrax

The aim of this work was to develop an oral method of vaccination against anthrax, since wide vaccination campaigns using this method require no special conditions, equipment, and instruments. Also, minimum number of medical personnel is sufficient to ensure control over the intake of the drug. Materials and methods. Domestic raw materials, consumables and reagents that passed the incoming inspection and met the requirements of State and industry standards, technical specifications, and the articles of the Pharmacopoeia were used for the work. Batches of anthrax vaccines based on Bacillus anthracis strain STI-1, manufactured at the Research Center (Kirov) of the “48th Central Research Institute” of the Ministry of Defense of Russia were put to the test. Results and discussion. The immunization schemes have been tested on animals, taking into account the features of the antigen. One of the crucial factors that determine the effectiveness of oral vaccination is the correct choice of the type and form of the oral anthrax vaccine administered enterally. It has been shown that in contrast to oral vaccines, the vaccine strain in enteral vaccines must be protected from the harmful effects of stomach contents. Thus, enteric-coated capsules coated with a shell that is resistant to the action of stomach acid were used for the study. The presented experimental data indicate that a single administration of the capsules with oral anthrax vaccine STI protects at least 70 % of laboratory animals from a highly virulent strain of the anthrax microbe and confirm the safety and non-reactogenicity of the drug. The developed laboratory technology makes it possible to obtain a finished product containing one inoculation dose of an oral vaccine for laboratory animals. So, a new method of vaccination has been designed. It is necessary to conduct preclinical and clinical trials to promptly introduce the oral administration of anthrax vaccine into medical practice as the simplest method for mass vaccination of humans

Classical swine fever: retrospective analysis of epidemic situation in Russian Federation (1996-2015)

Progress trends in classical swine fever (CSF) epidemic situation in the Russian Federation in 1996-2015 are discussed in the paper. Spatial shift of CSF outbreaks from the central regions of the country (2007-2012) to the western and eastern border regions of the Russian Federation (2013-2015) has been confirmed. Based on the analysis, a short-term prognosis for 2016 has been made as well as recommendations on DIVA-based measures for CSF eradication in domestic pigs and wild boars in the RF have been provided

Thiouronium Salt Derivatives Based on Vicinal Diamines as Potential Neuroprotectors

Most of the medicinal products that are currently approved and used in clinical practice for neurodegenerative diseases, in particular Alzheimer’s disease, have a compensatory mechanism of action that enhances neurotransmitter signalling. It is an urgent need to develop new medicinal products combining cognitive-enhancing, neuroprotective, and disease-specific effects resulting from a multi-target mechanism of action including, in particular, prevention of glutamate-induced neuronal calcium uptake and stabilisation of microtubules.The aim of this study was to search for potentially neuroprotective and tauopathy-alleviating medicines amongst new thiouronium salt derivatives based on vicinal diamines.Materials and methods. The study investigated the ability of thiouronium salts to block glutamate-induced 45Ca2+ uptake by synaptosomes prepared from the brain of Wistar rats. The authors evaluated effects of these new compounds on polymerisation of a preparation of C57bl mouse brain tubulin and microtubule-associated proteins. The evaluation was carried out in the presence of guanosine triphosphate (GTP) and based on specific absorbance changes at 355 nm due to formation of microtubules. The authors analysed the structure of these microtubules, using negative staining followed by transmission electron microscopy. The IC50 determination and the statistical analysis were performed using standard software (Excel and PRISM 6.02).Results. The authors developed a screening algorithm for a number of new thiouronium salt derivatives based on vicinal diamines and studied biological activity of these derivatives by the effects on glutamate-induced calcium uptake by synaptosomes and on microtubule assembly processes. The authors identified compounds suppressing glutamate-induced calcium uptake by synaptosomes, i.e. compounds with neuroprotective potential. In addition, a number of new compounds were able to stimulate GTP-dependent microtubule assembly processes. The authors observed formation of microtubules with a normal structure in the presence of isopropyl-N’-[2-(benzoylamino)-1,2-diphenylethyl]-N-ethylimidothiocarbamate hydrobromide and considered the compound a promising scaffold for further optimisation.Conclusions. Chemical modification of thiouronium salts is a promising direction for developing effective neuroprotectors and microtubule stabilisers

Characterization of tularemia foci in the Republic of Kazakhstan from 2000 to 2020

The wide distribution of tularemia in the territory of Kazakhstan is associated with landscape and geographical characteristics. This is explained by a combination of natural factors: the presence of certain types of rodents—reservoirs and sources, ectoparasites—carriers of the causative agent of tularemia. The study of the current spatial and temporal characterization of tularemia in Kazakhstan from 2000 to 2020 will determine the epidemiological status of tularemia and improve the monitoring system in Kazakhstan. In this work we demonstrated the results of a retrospective survey of natural foci of tularemia: analysis of vector, small mammal and human data. The spatial and temporal characteristics of tularemia from 2000 to 2020 in the territory of Kazakhstan were studied in comparison with historical data, including the description of tularemia outbreaks, the clinical picture, and the source of infection, transmission factors, and geographical coordinates of outbreak registration. Sampling was carried out by trapping rodents on snap traps and collecting ticks by rodent combing and by "flagging" methods. For the last 20 years, 85 human cases of tularemia have been reported. During the period from 2000 to 2020, more than 600 strains of F. tularensis were isolated from field rodents and ticks in the natural foci of tularemia. MLVA typing of F. tularensis strains isolated from natural foci of tularemia in Kazakhstan over the past 20 years. The results of retrospective monitoring indicate that currently active foci of tularemia include the Aktobe, West Kazakhstan, Almaty, East Kazakhstan, and Pavlodar regions. Low-activity natural foci are located in the territory of the Akmola, Karaganda, North Kazakhstan, Kostanay, Atyrau, Zhambyl, and Kyzylorda regions. There are no active natural foci of tularemia in the Mangystau and Turkestan regions. The widespread occurrence of tularemia in the country is associated with landscape and geographical features that contribute to the circulation of the pathogen in the natural focus. An analysis of natural foci of tularemia showed that it is necessary to continue monitoring studies of carriers and vectors for the presence of the causative agent of the F. tularensis, in order to prevent mass cases of human disease

Pharmacological sequestration of mitochondrial calcium uptake protects against dementia and β-amyloid neurotoxicity

All forms of dementia including Alzheimer's disease are currently incurable. Mitochondrial dysfunction and calcium alterations are shown to be involved in the mechanism of neurodegeneration in Alzheimer's disease. Previously we have described the ability of compound Tg-2112x to protect neurons via sequestration of mitochondrial calcium uptake and we suggest that it can also be protective against neurodegeneration and development of dementia. Using primary co-culture neurons and astrocytes we studied the effect of Tg-2112x and its derivative Tg-2113x on β-amyloid-induced changes in calcium signal, mitochondrial membrane potential, mitochondrial calcium, and cell death. We have found that both compounds had no effect on β-amyloid or acetylcholine-induced calcium changes in the cytosol although Tg2113x, but not Tg2112x reduced glutamate-induced calcium signal. Both compounds were able to reduce mitochondrial calcium uptake and protected cells against β-amyloid-induced mitochondrial depolarization and cell death. Behavioral effects of Tg-2113x on learning and memory in fear conditioning were also studied in 3 mouse models of neurodegeneration: aged (16-month-old) C57Bl/6j mice, scopolamine-induced amnesia (3-month-old mice), and 9-month-old 5xFAD mice. It was found that Tg-2113x prevented age-, scopolamine- and cerebral amyloidosis-induced decrease in fear conditioning. In addition, Tg-2113x restored fear extinction of aged mice. Thus, reduction of the mitochondrial calcium uptake protects neurons and astrocytes against β-amyloid-induced cell death and contributes to protection against dementia of different ethology. These compounds could be used as background for the developing of a novel generation of disease-modifying neuroprotective agents

Techniques of blood sampling for detection of African swine fever virus in wild boar and domestic pigs in the field conditions

It is thought that due to the high virulence of the African swine fever virus its circulation in the Russian Federation is accompanied by a low seroprevalence. However taking into account a long-term ASF unfavourable situation, the introduction of the virus into the wild boar population, and the occurrence of attenuated viral variants, the significance of serological testing aimed at the detection of viral antibodies is increasing. To collect field samples of biological material from animals for molecular genetic, virological, and serological tests, filter paper, as well as swabs, can be used. The specificity and sensitivity of enzyme-linked immunosorbent assay when testing blood absorbed by filter paper are worse than those shown when testing sera, but they allow effective detection of African swine fever virus antibodies. It was demonstrated that blood absorbed on filter paper can be used for the immunoblot analysis, but the optimum performance could be achieved when the immunoperoxidase technique in combination with samples, taken by swabs was used. When comparing results of enzyme-linked immunosorbent assay performed on sera collected from domestic pigs (infected with ASFV isolates Antonovo 07/14 and Sobinka 07/15), and blood from ear veins absorbed on filter paper the sensitivity was 88.9%, specificity – 90.6%. However, the use of the immunoperoxidase technique for testing blood from swabs showed 100% coincidence with ELISA, while testing of sera with immunoperoxidase technique was superior to ELISA in sensitivity. This means blood sampling using swabs may be recommended for tests after proper validation. This technique can be especially useful for collecting data about infected wild boars because effective eradication strategies are impossible without such data