Cellular energy functions of a subline of mouse fibroblasts resistent to the action of ethidium bromide]

The respiration of subline Leb-25 cells, resistant to ethidium bromide (EB, 25 g/ml), is 2.5 times slower than the respiration of parental L cells of mouse fibroblasts. The EB resistant cells have a normal level of ATP. Disturbances of mitochondrial functions can be observed such as a defect of the succinate dehydrogenase complex and the uncoupling of respiration and oxidative phosphorylation in mitochondria of Leb-25 cells.     

Effect of alkaloid sanguinarine and a pharmaceutical preparation ukrain on modulation of vesicular membrane fusion and actin cytoskeleton of macrophages

A study was made of modulations of lysosome-phagosome fusion process and of fibrillar actin content in mouse peritoneal macrophages by an antitumor alkaloid sanguinarine and a derivative drug Ukrain. In addition, effects of these substances on in vitro polymerization of monomeric globular actin from rabbit muscle were investigated. Sanguinarine and Ukrain stimulated lysosome-phagosome fusion and increased the content of polymerized fibrillar form of actin in mouse macrophages. Effects of these substances were enhanced at their higher concentrations. Both sanguinarine and Ukrain induced in vitro polymerization of globular actin from rabbit muscle. A possible role of sanguinarine and Ukrain in changing vesicular membrane states during intracellular membrane interaction in lysosome-phagosome fusion process was discussed. The influence of these substances on actin polymerization and actin cytoskeleton rearrangement was evaluated. It could be supposed that sanguinarine and Ukrain may alter intracellular membrane transport.     

Regulation levels of photosynthesis processes

The basic mechanisms of kinetic regulation of photosynthetic processes are considered, which provide a strict light regulation of electron transfer in photosynthetic reaction centers and a more flexible regulation at the level of interaction of photosystems, transmembrane ion fluxes and coupling with dark reactions of the Calvin cycle. A generalized model was developed, which integrates the modern knowledge about photosynthetic processes of higher plants. The general principles of multilevel regulation in photosynthetic systems are discussed.     

Characteristic features of adaptation to experimental conditions in primates with various initial keeping conditions

Ethological study of emotional state and behavior was carried out in male macaques of two species (Macaca mulatta and Macaca fascicularis), which were divided in three groups according to their initial keeping: isolated, family, and gregarious. During instrumental conditioning, the initial keeping was changed for identical conditions (individual caging or sitting in a primatological chair). It was shown that adaptation to stress associated with a sharp enviromental change depended on initial keeping conditions. Monkeys brought up in family with experience of both intra- and interspecies interactions (for example, monkey--human) had the highest adaptation and learning abilities. Individual and gregarious keeping of monkeys impoverished their individual experience, and their adaptation to experimental conditions required additional efforts. The learning of individually caged monkeys was successful, if their keeping conditions were not changed. Initially gregarious monkeys were successfully trained after their habituation to contact with humans.     

A kinetic model of the cytochrome bf complex. Evaluation of kinetic parameters

A kinetic model of the cytochrome bf complex was developed on the assumption that the Q-cycle operates. The bf complex was considered as a membrane enzyme catalyzing the electron transfer from plastoquinol to plastocyanine, which is coupled with proton translocation from the chloroplast stroma to the thylakoid lumen. The dependence of the electron transfer rates on the value of the transmembrane electric potential was taken into account. The model was applied to describe the experimental data on the flash-induced turnover of cytochromes b, plastocyanine, and the kinetics of proton deposition in the thylakoid lumen. The estimation of model parameters was performed.     

Comparative characterization of laboratory-made selective nutrient media for Salmonella accumulation

In this work the results of the trial of three selective nutrient media for Salmonella accumulation, viz. Leifson's selenite broth produced by the Research and Manufacturing Amalgamation (RMA) Nutrient Media, tetrarathionate broth (Müller's medium), laboratory-prepared, and newly developed MA-broth produced by the RMA Nutrient Media, are presented. The results of 6- and 24-hour incubation in these selective media was evaluated. As found in this study, the laboratory-prepared medium was most effective for the accumulation of salmonellae (S. paratyphi, S. typhi, S. gallinarum). With respect to the possible concomitant microflora (Escherichia coli and shigellae), the inhibiting properties of MA-broth were superior to those of Leifson's medium, but inferior to those of Müller's medium.     

Influence of acute and chronic administrations of beta-casomorphins on the maternal motivation in albino rats

The influence of food-derived opioid peptides beta-casomorphines on the manifestation of nursing albino rats maternal behavior was investigated. It was shown that both acute and chronic (during the postnatal period) administration of beta-casomorphin-7 (Tyr-Pro-Phe-Pro-Gly-Pro), the typical representative of this group of peptides, decreases the level of the parental motivation. The effects of beta-casomorphin-7 were naloxone-dependent; N-terminal-reduced analogues had a significantly lesser activity. The obtained results testify in favor of the probable role of casein opioid fragments which were formed in mammary glands of a nursing female, in the development of maternal behavior abnormalities. At the same time, beta-casomorphins could be considered as the limiting factors to the excessive manifestation of the parental motivation.