Recognition of specific sialoglycan structures by oral streptococci impacts the severity of endocardial infection.

Streptococcus gordonii and Streptococcus sanguinis are primary colonizers of the tooth surface. Although generally non-pathogenic in the oral environment, they are a frequent cause of infective endocarditis. Both streptococcal species express a serine-rich repeat surface adhesin that mediates attachment to sialylated glycans on mucin-like glycoproteins, but the specific sialoglycan structures recognized can vary from strain to strain. Previous studies have shown that sialoglycan binding is clearly important for aortic valve infections caused by some S. gordonii, but this process did not contribute to the virulence of a strain of S. sanguinis. However, these streptococci can bind to different subsets of sialoglycan structures. Here we generated isogenic strains of S. gordonii that differ only in the type and range of sialoglycan structures to which they adhere and examined whether this rendered them more or less virulent in a rat model of endocarditis. The findings indicate that the recognition of specific sialoglycans can either enhance or diminish pathogenicity. Binding to sialyllactosamine reduces the initial colonization of mechanically-damaged aortic valves, whereas binding to the closely-related trisaccharide sialyl T-antigen promotes higher bacterial densities in valve tissue 72 hours later. A surprising finding was that the initial attachment of streptococci to aortic valves was inversely proportional to the affinity of each strain for platelets, suggesting that binding to platelets circulating in the blood may divert bacteria away from the endocardial surface. Importantly, we found that human and rat platelet GPIbα (the major receptor for S. gordonii and S. sanguinis on platelets) display similar O-glycan structures, comprised mainly of a di-sialylated core 2 hexasaccharide, although the rat GPIbα has a more heterogenous composition of modified sialic acids. The combined results suggest that streptococcal interaction with a minor O-glycan on GPIbα may be more important than the over-all affinity for GPIbα for pathogenic effects

Differential surface activation of the A1 domain of von Willebrand factor

The clotting protein von Willebrand factor (VWF) binds to platelet receptor glycoprotein Ibα (GPIbα) when VWF is activated by chemicals, high shear stress, or immobilization onto surfaces. Activation of VWF by surface immobilization is an important problem in the failure of cardiovascular implants, but is poorly understood. Here, the authors investigate whether some or all surfaces can activate VWF at least in part by affecting the orientation or conformation of the immobilized GPIbα-binding A1 domain of VWF. Platelets binding to A1 adsorbed onto polystyrene surfaces translocated rapidly at moderate and high flow, but detached at low flow, while platelets binding to A1 adsorbed onto glass or tissue-culture treated polystyrene surfaces translocated slowly, and detached only at high flow. Both x-ray photoelectron spectroscopy and conformation independent antibodies reported comparable A1 amounts on all surfaces. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and near-edge x-ray absorption fine structure spectra suggested differences in orientation on the three surfaces, but none that could explain the biological data. Instead, ToF-SIMS data and binding of conformation-dependent antibodies were consistent with the stabilization of an alternative more activated conformation of A1 by tissue culture polystyrene and especially glass. These studies demonstrate that different materialsurfaces differentially affect the conformation of adsorbed A1 domain and its biological activity. This is important when interpreting or designing in vitro experiments with surface-adsorbed A1 domain, and is also of likely relevance for blood-contacting biomaterials

The Bacterial Fimbrial Tip Acts as a Mechanical Force Sensor

The subunits that constitute the bacterial adhesive complex located at the tip of the fimbria form a hook-chain that acts as a rapid force-sensitive anchor at high flow

Principles of the System Approach in Family Consulting

The article considers the problem of the system model of family counseling, in particular, the analysis of the family as a social system, as a complex of elements and their properties, which are in dynamic connections and relationships. The analysis of the theory of systems and the description of the principles of family counseling is carried out. Particular attention is paid to highlighting the main provisions of the individual (“adlerian”) psychology in counseling the family. Currently among specialists there is a high interest in the provision of psychological assistance to a family in crisis. This is largely due to the fact that over the past decades, the institution of the family in this country is experiencing an increase in destructive tendencies. This is evidenced by an increase in the number of appeals to school psychologists, psychological counseling, psychological services and centers from both the individual members of the family and families in general. The psychological help to the family is positioned as a relatively new field of practice for a psychologist. The practice of counseling, including family, is largely determined by the theoretical skills of the counselor, primarily as (s)he understands the personality, determination of behavior, the source of family problems, and the possibility of change. Today, practitioners prefer the integrative method, which is a system approach. The purpose of this article is to analyze the theory of systems as the basis of family counseling. The system model of family counseling is considered to be one of the youngest and most widespread models that received their recognition at the end of the twentieth century

Numerical simulations of a subsonic round jet with transverse acoustic and mechanical forcing

The results of numerical experiments on the bifurcation effects for a free round jet caused by acoustic or vibrational excitations are presented. The three-dimensional distributions of the instantaneous and time-averaged velocity vector components have been obtained and analyzed. The effects of Strouhal and Reynolds numbers on the jet splitting angle, as well as those of the amplitude and type of jet perturbations is discussed in such a comparative parametric study

Assessment of the differentiation of social and economic development of the municipal districts in the Voronezh region

One of the problems that have arisen in the past and have an inertial impact on the development of the Russian Federation is the problem of heterogeneity of the country’s socio-economic space. The large scale of the space of Russia predetermines the predominantly macroscopic nature of the regulatory impact, the object of which is large territorial formations: economic districts, federal districts, regions of the Russian Federation. Each separate region, each municipality is a complex system with a set of unique factors: geographic location, climatic conditions, resource potential, population, etc. The article presents the author’s methodology for assessing the differentiation of social and economic development of municipalities in the Voronezh region. In modern conditions, the formation of convenient and effective methods and tools for measuring sustainable social and economic development, which make it possible to give an unambiguous interpretation of the results, is of high value both from a research and management point of view. On the basis of the author’s methodology, an assessment of the differentiation of the social and economic development of municipalities in the Voronezh region has been carried out. The proposed method, having individual characteristics in limiting the number of basic indicators along with the existing approaches, contributes to obtaining more objective results and allows it to be used in the development of a regional social and economic Strategy. These indicators are among the most important areas of the region’s social and economic system

The role of soil and plant cover as drivers of soil macrofauna of the Dnipro River floodplain ecosystems

Floodplain ecosystems are hotspots of biological diversity and perform important ecosystem functions in the landscape. The key to understanding the sustainability of ecosystem function is knowledge of the relationships between ecosystem components. The article reveals the role of morphological and physical properties of soil, as well as phytoindication of environmental factors as drivers of biological diversity of soil macrofauna of protected ecosystems of the Dnipro River floodplain. The studies were conducted in the forest floodplain ecosystems of the “Dnipro-Orilskiy” Nature Reserve. The studies of morphological properties of soils allowed us to identify the representatives of two reference groups: Fluvisol and Gleysol. The soil physical property data were subjected to principal component analysis, which extracted four principal components whose eigenvalues exceeded unity and described 79.9% of the variation in traits. The principal components of variation in soil physical properties and phytoindication assessments of environmental factors were used as predictors of the community structure of soil macrofauna. These predictors were able to explain 29.6% of the community variation. Physical soil properties are most important as a driver of soil macrofauna. The morphological properties of the soil and phytoindicator assessments are able to explain a much smaller part of the community variation. The pure influence of the predictors is small, indicating that they interact significantly in influencing soil animals. The results obtained have implications for the development of optimal strategies for floodplain ecosystem management and biodiversity conservation

The demographic potential of the Voronezh region as a factor of human capital development

Population is the key object of public policy, as it forms the demographic potential, without which the development of either a country or the world economy as a whole is impossible. The study of the location of the population, the number of labour resources, sex and age structure are important government tasks, the proper implementation of which forms the potential of the population. The aim of the article is to estimate the demographic potential of Voronezh Oblast. To achieve the goal the methods of statistical analysis were used, namely: grouping, relative, average, and index methods. Results. A comprehensive assessment of the demographic potential of the region has been made. The study will make it possible to make refined forecasts of demographic development of the region