Molecular organization of bacteriochlorophyll in the light-converging B850 complex of purple bacteria

The light-harvesting bacteriochlorophyll-protein complex B850 has been isolated from two species of purple bacteria, Rhodopseudomonas palustris and Chromatium minutissimum. Absorption and fluorescence spectra at 20 degrees and--196 degrees C of this complex were registered. Second derivatives of the absorption spectra, Stepanov's relation and computer curve analyses in terms of asymmetrical Gaussian components show that absorption spectra consist of five and fluorescence spectra--of three components. These components were analysed in terms of exciton interaction among bacteriochlorophyll molecules. Data obtained were used for building-up of the molecular model of the complex.     

Parameters of systemic hemodynamics in conscious rats with acute streptozotocin diabetes]

The effect of acute streptozotocin-induced diabetes mellitus on the systemic hemodynamic parameters was studied in conscious rats by thermodilution technique. Male Wistar rats were made diabetic with a single intravenous injection of streptozotocin (STZ, 50 mg/kg). The most important finding of this work was the elucidation of the systemic vasodilation and increased cardiac index one day after STZ injection. Such alteration in hemodynamic parameters could result in the increased blood flow and capillary hypertension in some vascular beds and, therefore, be considered as a pathogenic factor in the development of diabetic microangiopathy.     

Biosynthesis of levorin and activity of several enzyme systems of Streptomyces levoris depending on culture conditions

The regularities of changes in the main oxidation-reduction enzymes of the tricarboxylic acid cycle (TAC) and the pentose cycle were studied under different cultivation conditions: with the use of the control soybean-corn-hydrol medium and the medium with addition of a biostimulant produced by C. tropicalis. It was shown that the activity levels of the dehydrogenase systems of the TAC and the pentose cycle of S. levoris grown in the presence of the biostimulant were higher. The increase in the production levels of levorin due to addition of the biostimulant was connected with the activity of the systems responsible for regeneration of NADP.H2.     

Estimation of the evolutionary stability of the Influenza A virus: Prediction of variable regions in the domain structure of the M1 protein

Influenza virus is a human pathogen that is responsible for several pandemics with high death rates. Two programs were written for the statistical analysis of the coding regions of genes from extensive samples of Influenza A virus. While inner viral proteins appeared to be evolutionarily stable, surface antigens and the NS1 nonstructural protein are highly variable. Using programs to predict the evolutionarily variable regions inside the M1 protein sequence it was shown that the N-domain is the most conserved domain while the M- and C-domains are the most variable. In addition, the C-domain was shown to be the most unfolded one, according to prediction by the DISOPRED algorithm and, thus, possesses the most structural plasticity.     

Dynamics of the measured oxidative potential of preserved blood]

An expression for oxidative potential (phi) of conservated blood is suggested proceeding from the assumption of the steady character of the system methemoglobin -- hemoglobin, oxihemoglobin included. This system is suggested to be responsible for the formation of phi in the blood. The equation qualitatively describes the experimental relation of phi on time at the contact of blood with air. Relationship between the changes of oxidative potential in the blood during its storage with the state of conservated blood hemoglobin is discussed. The experimental data show that measuring of the oxidative potential may be the basis for creating a control method for the state of conservated blood during its storage.     

Effect of myelopeptides on the postradiation recovery of the thymus

The influence of myelopeptides on the postirradiation recovery of thymus was studied by estimating the thymus cellularity, proliferation of thymocytes in vivo, and composition of thymocyte subpopulations characterized by the expression of Thy-1,2 and Sc-1 antigens and receptors for peanut agglutinin. A single intraperitoneal administration of myelopeptide (the optimal dose of 10(-5) mg/mouse) 24 h following 6.5 Gy irradiation gives rise to proliferative and differentiation processes favoring the recovery of thymus.