The identification of nitrate reductase fromEscherichia coli as the antigen for a monoclonal antibody of unknown specificity

The immunoaffinity chromatography of total membrane proteins fromEscherichia coli helped determine the specificity of the monoclonal antibody 3A6 that was obtained upon immunization of mice with nicotinamide nucleotide transhydrogenase preparations and reacted with an unknownE. coli antigen. Proteins with apparent molecular masses of 150, 45, and 20 kDa were isolated and identified byN-terminal sequencing as the subunits of nitrate reductase. This conclusion was confirmed by immunoblotting with the 3A6 antibody of the proteins from theE. coli cells grown upon induction of nitrate reductase. It was shown that the 3A6 antibody specifically recognizes the α subunit of nitrate reductase, and the formation of the enzyme-antibody complex does not result in a loss of the enzyme catalytic activity.     

Effect of testosterone on the rate of synthesis of cytoplasmic and nuclear proteins in the reproductive tract of rabbit embryos in vitro

The rate of synthesis of cytoplasmic and nuclear proteins in the reproductive tract and muscle of rabbit embryos from 17 to 23 days of development was estimated by the intensity of 3H-leucine incorporation per 1 mg protein for 30 min in vitro. Testosterone increased several-fold the rate of synthesis of both cytoplasmic and nuclear proteins. At the same time the intensity of synthesis of nuclear proteins was several times higher that of cytoplasmic ones and attained the max values on the 20 day of development.     

Comparative study of several preparations in different models of cerebral hypoxia

The antihypoxic effects of gutimine, piracetam, sodium hydroxybutyrate and lithium hydroxybityrate were studied on different models of brain hypoxia. All the drugs under study produced a remarkable antihypoxic effect in experimental asphyxic hypoxia, increasing brain resistance to oxygen deficiency and rapidly restituting brain function. Drug pretreatment of the animals with carotid artery occlusion raised the number of animals which survived 24 h after the operation. GABA salts appeared the most effective. Sodium hydroxybutyrate increased the lifespan of rats under histotoxic hypoxia.     

Versatility of the green microalga cell vacuole function as revealed by analytical transmission electron microscopy

Vacuole is a multifunctional compartment central to a large number of functions (storage, catabolism, maintenance of the cell homeostasis) in oxygenic phototrophs including microalgae. Still, microalgal cell vacuole is much less studied than that of higher plants although knowledge of the vacuolar structure and function is essential for understanding physiology of nutrition and stress tolerance of microalgae. Here, we combined the advanced analytical and conventional transmission electron microscopy methods to obtain semi-quantitative, spatially resolved at the subcellular level information on elemental composition of the cell vacuoles in several free-living and symbiotic chlorophytes. We obtained a detailed record of the changes in cell and vacuolar ultrastructure in response to environmental stimuli under diverse conditions. We suggested that the vacuolar inclusions could be divided into responsible for storage of phosphorus (mainly in form of polyphosphate) and those accommodating non-protein nitrogen (presumably polyamine) reserves, respectively.The ultrastructural findings, together with the data on elemental composition of different cell compartments, allowed us to speculate on the role of the vacuolar membrane in the biosynthesis and sequestration of polyphosphate. We also describe the ultrastructural evidence of possible involvement of the tonoplast in the membrane lipid turnover and exchange of energy and metabolites between chloroplasts and mitochondria. These processes might play a significant role in acclimation in different stresses including nitrogen starvation and extremely high level of CO₂ and might also be of importance for microalgal biotechnology. Advantages and limitations of application of analytical electron microscopy to biosamples such as microalgal cells are discussed.