Effect of vasopressin on the ATP-ase activity of microsomal fractions of rabbit heart and liver]

It was shown that intravenous injection of vasopressin in a dose of 5 pressor units per 1 kg of body weight led to changes in the ATP-ase activity of the heart and liver microsomes in one hour. These changes coursed in a different direction, i.e. ATP-ase activity of the heart microsomes increased, and ATP-ase activity of the liver microsomes decreased.     

Kinetics of reversible inhibition of cholinesterases by quaternary diaminoalkyl esters of aromatic dicarboxylic acids]

Reversible inhibition of acetylcholinesterase (AChE) from bovine erythrocytes and butyrylcholinesterase (BuChE) from horse blood serum by quaternary diaminoalkyl esters of suberic (D-6), p-phenylenediacetic (PK-139), p-phenylenedipropionic (PK-154 and PK-155), p-phenylenediacrylic (PK-150 and PK-151) and phthalic (PK-105) acids, was studied under the following incubation conditions: pH 7.5, 25 degrees C, 0.1 M KCl. The inhibition kinetics were of a mixed competitive-incompetitive type, the incompetitive component alpha'-having higher values for AChE (0.26-0.60) than for BuChE (0.10-0.20). Diester PK-150 selectively inhibited BuChE (Ki=3.0-10(-6) M); its Ki value for AChE was 4.0-10(-4) M. The other diesters had a stronger inhibitory effect on AChE than on BuChE. High values of alpha' observed during AChE inhibition cannot be interpreted in terms of interaction of those bisquaternary compounds with the anionic site of the acetylated active centre and are probably due to their sorbtion at the peripheral anionic sites. Incompetitive inhibition constants (K'i=Ki/alpha') of BuChE by the diesters PK-139, PK-154 and PK-150 were found to be values of the same order as substrate inhibition constants determined in the course of BuChE hydrolysis of these diesters. Incompetitive inhibition found for the esters studied and substrate inhibition during hydrolysis of these compounds are presumably due to the same mechanism.     

Relation between the morphogenesis of Xanthomonas rubrilineans and biosynthesis of aminopeptidase in the process of growth and development of its producer]

The dynamics of growth and development of Xanthomonas rubrilineans, a culture producing intracellular aminopeptidase, was studied. A difference between the growth rate determined by intensity of the total biomass accumulation and the rate of the culture multiplication was found. The difference was due to the presence of two phases in the culture development during the exponential growth: the phase of increasing the linear sizes of the cells and the phase of the culture intensive multiplication. The most intensive synthesis of aminopeptidase was observed during the phase of increasing the linear sizes of the cells. The dynamics of consumption of the main sources of carbon and nitrogen by the culture was investigated.     

Perceptual learning in children during perception of the emotional component of speech utterances: The influence of age and gender

Perceptual learning was examined during perception of the emotional component of speech when a valid signal was presented against a background of noise to 7-to 17-year-old boys and girls. Accuracy of emotion recognition (AR) and response time (RT) were recorded in two consecutive test series. Analysis of variance of the results demonstrated a high significance of the series order for both the RT and the AR. The study revealed the ontogenetic features of the characteristics of perceptual learning under these conditions. The most notable changes were observed in the time of discriminating emotions. Mathematically, perceptual learning was modeled exponentially. Model parameters such as the rate of perceptual learning and the initial level of perceptual performance were estimated. It was found that the rate of learning, calculated for both the AR and the RT, had close values and similar trends of changes in both the male and the female samples. This suggests that the rate of perceptual learning is an invariant characteristic of perception of the emotional component of speech in a child. The initial level of perceptual performance increased as a function of age, more notably in the boys than in the girls. The initial level of the RT decreased with age in the girls and almost did not depend on age in the boys. However, the integral AR suggests that the age-related changes in the initial level of the integral perception of emotions are identical in girls and boys.     

Comparative assessment of different approaches for obtaining terminally differentiated cell lines

The study of pathogenesis of muscle disorders needs an appropriate cell model. In the field of muscle research, there is no general cell line considered standard for studying muscular and neuromuscular diseases. Most cell lines are incapable of differentiation into a muscle lineage exhibiting morphological and physiological properties of mature muscle cells and can hardly be genetically modified. The goal of our study was to find an informative cell model of muscle differentiation suitable for examination of muscular pathogenesis in vitro. We assayed cultured human mesenchymal stem cells (MSCs), mature murine muscle fibers, and primary murine satellite cells. It was shown that MSCs had very low capacity for myogenic differentiation; they were able to differentiate only in the presence of C2C12 cells. Lentiviral transduction had a toxic effect in primary myofiber cultures, and positively transduced cells were unable to respond to electrical stimulation, i.e., were functionally inactive. Satellite cells proved to be the most appropriate cell model, since they were easily transduced with lentiviruses and rapidly formed myotubes in the differentiation medima. Functional analysis of induced myotubes showed their ability to react to electrical and chemical stimulation. The patch-clump technique showed the presence of potassium and calcium channels. Collectively, the results show that cultured satellite cells are the most promising cell line for further experiments to explore molecular pathways in muscle pathologies.