“What Doesn’t Kill You Makes You Stronger”: Future Applications of Amyloid Aggregates in Biomedicine

Amyloid proteins are linked to the pathogenesis of several diseases including Alzheimer’s disease, but at the same time a range of functional amyloids are physiologically important in humans. Although the disease pathogenies have been associated with protein aggregation, the mechanisms and factors that lead to protein aggregation are not completely understood. Paradoxically, unique characteristics of amyloids provide new opportunities for engineering innovative materials with biomedical applications. In this review, we discuss not only outstanding advances in biomedical applications of amyloid peptides, but also the mechanism of amyloid aggregation, factors affecting the process, and core sequences driving the aggregation. We aim with this review to provide a useful manual for those who engineer amyloids for innovative medicine solutions.

ESIPT-Related Origin of Dual Fluorescence in the Selected Model 1,3,4-Thiadiazole Derivatives

In our previous work, we discussed the emergence of the dual fluorescence phenomenon in selected compounds from the group of 1,3,4-thiadiazoles. The results obtained in a number of experimental studies, supported by [TD]DFT calculations, clearly indicated that the phenomenon of dual fluorescence stemmed from an overlap of several factors, including the correct conformation of the analyzed molecule and, very significantly in this context, aggregation effects. Where those two conditions were met, we could observe the phenomenon of intermolecular charge transfer (CT) and the emergence of electronic states responsible for long wave emissions. However, in light of the new studies presented in this paper, we were able, for the first time, to provide a specific theory for the effect of dual fluorescence observed in the analyzed group of 1,3,4-thiadiazoles. We present the results of spectroscopic measurements conducted for two selected analogues from the 1,3,4-thiadiazole group, both in polar and non-polar solvents, which clearly evidence (as we have already suspected in the past, albeit have not shown in publications to date) the possibility of processes related to emission from the tautomer formed in the process of excited state intramolecular proton transfer, which is responsible for the long-wavelength emissions observed in the selected analogues. The presented results obtained with the use of UV-Vis, fluorescence (stationary and time-resolved), FTIR, and Raman spectroscopy, as well as from calculations of dipole moment changes between the ground and excited state with the use of two derivatives with different structures of the resorcylic system, corroborated our standing hypothesis. At the same time, they excluded the presence of ground state keto forms of the analyzed analogues unless necessitated by the structure of the molecule itself. In this case, aggregation factors enhance the observed effects related to the dual fluorescence of the analyzed compounds (by way of AIE—aggregated induced emissions).

Adhesion of freshwater sponge cells mediated by carbohydrate–carbohydrate interactions requires low environmental calcium

Marine ancestors of freshwater sponges had to undergo a series of physiological adaptations to colonize harsh and heterogeneous limnic environments. Besides reduced salinity, river-lake systems also have calcium concentrations far lower than seawater. Cell adhesion in sponges is mediated by calcium-dependent multivalent self-interactions of sulfated polysaccharide components of membrane-bound proteoglycans named aggregation factors. Cells of marine sponges require seawater average calcium concentration (10 mM) to sustain adhesion promoted by aggregation factors. We demonstrate here that the freshwater sponge Spongilla alba can thrive in a calcium-poor aquatic environment and that their cells are able to aggregate and form primmorphs with calcium concentrations 40-fold lower than that required by marine sponges cells. We also find that their gemmules need calcium and other micronutrients to hatch and generate new sponges. The sulfated polysaccharide purified from S. alba has sulfate content and molecular size notably lower than those from marine sponges. Nuclear magnetic resonance analyses indicated that it is composed of a central backbone of non- and 2-sulfated α- and β-glucose units decorated with branches of α-glucose. Assessments with atomic force microscopy/single-molecule force spectroscopy show that S. alba glucan requires 10-fold less calcium than sulfated polysaccharides from marine sponges to self-interact efficiently. Such an ability to retain multicellular morphology with low environmental calcium must have been a crucial evolutionary step for freshwater sponges to successfully colonize inland waters.

análisis en redes de aprendizaje organizacional como herramienta en la administración empresarial

En este trabajo se presentan los avances de nuestra investigación, la cual consiste en la aplicación de la Perspectiva de Redes en el estudio del Proceso de Aprendizaje Organizacional en una empresa de servicio ubicada en la Ciudad de México. El análisis de redes representa una herramienta fundamental en el proceso de modelación de Sistemas, específicamente en este trabajo se trata de sistemas sociales, los cuales se caracterizan como un tipo de Sistemas Complejos. Se propone construir y analizar una red, en la cual los nodos representan a los empleados de la compañía y los arcos simbolizan una relación de aprendizaje colaborativo. Se construye la red y se analiza su estructura utilizando el software PAJEK diseñado por Vladimir & Mrvar (2016). Con el propósito decomprobar tres suposiciones acerca de la misma. La primera suposición es que la estructura de esta red podría aproximarse al modelo de red libre de escala bajo la regla de conexión preferencial, la segunda suposición es que los factores de agregación en la red podrían ser: la experiencia de los empleados, la distancia, el género, relaciones de amistad y jerarquía. AbstractThis paper presents the advances of our research, which consists in the application of the Network Perspective in the study of theOrganizational Learning Process in a service company located in Mexico City. The analysis of networks represents a fundamental tool in the process of modeling of Systems, specifically in this work it deals with social systems, which are characterized as a type of Complex Systems. It is proposed to build and analyze a network, in which the nodes represent the employees of the company and the arcs symbolize a collaborative learning relationship. The network is built and itsstructure is analyzed using the PAJEK software designed by Vladimir & Mrvar (2016). In order to check three assumptions about it. The first assumption is that the structure of this network could approximate the scale-free network model under the preferential connection rule, the second assumption being that aggregation factors in the network could be: employee experience, distance, gender, relations of friendship and hierarchy.KeywordsOrganizational learning, Social network analysis, Complex networks, Organizational learning networks, Complex Systems.

The analysis of group в streptococcal clinical strains for the presence of the genes encoding for potential adherence factors and localized on the «pathogenicity islands»

The collection of group В streptococcal clinical strains has been analyzed for the presence of genes encoding for putative adherence and aggregation factors. The presence of the genes designated as sspB1 and sspB2 were tested by PCR and DNA hybridization. The genes under study located in GBS genome on pathogenicity islands were found to be heterogeneous and could be associated with urological or invasive diseases. No significant correlation between the GBS serotype and sspB genes pattern have been discovered.