Neuronal activity controls transsynaptic geometry

The neuronal synapse is comprised of several distinct zones, including presynaptic vesicle zone (SVZ), active zone (AZ) and postsynaptic density (PSD). While correct relative positioning of these zones is believed to be essential for synaptic function, the mechanisms controlling their mutual localization remain unexplored. Here, we employ high-throughput quantitative confocal imaging, super-resolution and electron microscopy to visualize organization of synaptic subdomains in hippocampal neurons. Silencing of neuronal activity leads to reversible reorganization of the synaptic geometry, resulting in a increased overlap between immunostained AZ and PSD markers; in contrast, the SVZ-AZ spatial coupling is decreased. Bayesian blinking and bleaching (3B) reconstruction reveals that the distance between the AZ-PSD distance is decreased by 30 nm, while electron microscopy shows that the width of the synaptic cleft is decreased by 1.1 nm. Our findings show that multiple aspects of synaptic geometry are dynamically controlled by neuronal activity and suggest mutual repositioning of synaptic components as a potential novel mechanism contributing to the homeostatic forms of synaptic plasticity

Quantum-chemical calculation of the adsorption energy of the Pb atom on the graphene

© 2018 Author(s). Graphene can be used as sensors to detect toxic heavy metals in peripheral blood. This requires a clear understanding of adsorption process on the graphene surface. The DFT-functional method is used to calculate adsorption energy. In the article we present the calculation results and analyse interaction of Pb atom with graphene surface. It is shown that the Pb atom in B-site position on a graphene plane has a minimum of energy

Gallium(III) Citrato Complexes in Solution

The complexing gallium(III) with citric acid at pH from 2 to 10 and the gallium(III) and citric acid concentrations from 0.005 to 0.025 mol/l is studied by using pH titration. The stability constants of 1 : 1 complexes of various degrees of protonation formed in the system are found by mathematical modeling