Glutamine synthetase isolated from human brain: octameric structure and homology of partial primary structure with human liver glutamine synthetase

Glutamine synthetase (GS) has been purified from the cytosolic fraction of non-frozen human brain tissue. The purified GS migrated as a main band around 44 kD on reducing SDS-PAGE. Two-dimensional electrophoresis revealed heterogeneity within subunits of GS. The masses of eight different peptides from a tryptic digest of GS as measured by high resolution MALDI-MS matched with the respective masses from an in silico tryptic fingerprint of the Swiss-Prot database entry of human liver GS, proving that at least 24% of the primary sequences of GS from brain and liver are identical. Sedimentation equilibrium profiles obtained from analytical ultracentrifugation experiments at 10°C showed that human brain GS is mainly octameric. The quaternary structure of human brain GS at 10 M (subunit concentration) was not significantly affected by cations, such as magnesium (5 and 20 mM) or manganese (0.2 and 1 mM) within the range of pH 7.1-7.8.     

Microcalorimetric study of native cells of the microalgae Spirulina platensis in the temperature range (2-55)C

Thermal effects occurring upon heating a culture of blue-green microalgae Spirulina platensis in the temperature range 5-55 degrees C were studied. Under these conditions, an intensive heat evolution was observed. The heat evolution-versus-temperature curve has a peak with a maximum at approximately 45 degrees C and two distinct shoulders at approximately 25 and 40 degrees C. It was found that heat evolution Q at heating rates below 0.083 degree C/min does not change and is (381 +/- 20) J/g of dry biomass. It was concluded that this value is optimal for maintaining the cell viability (in particular, respiration) under anaerobic conditions, in the dark and in the stationary regime.     

Nutrient media for the isolation and accumulation of Listeria

Dried culture media for the isolation and accumulation of Listeria from pathological material and foodstuffs have been developed. The media are suitable for use in bacteriological and sanitary-hygienic practice. The optimum nutrient base has been selected: dried broth (from sprat hydrolysate), produced by the Research and Manufacturing Amalgamation "Culture Media". The optimum concentrations of ingredients, stimulating the growth of Listeria and inhibiting the growth of associated microbes, have been experimentally established. The samples of died accumulation and isolation culture media ensuring the growth of L. monocytogenes, diluted 10(-6), after 24-hour incubation at 37 degrees C have been obtained. The possibility of using these media for the bacteriological diagnosis of listeriosis in pregnant women has been demonstrated.     

Effects of the bee and various snake venoms on the rat thermoregulation

The most sensitive organ to any kind of venoms is the skin, whereas muscles response of milder, and the intestine response reveals no difference between effects of different venoms. The isobarin desympathetising effect combined with V.lebetina venom shows that the venom affects thermoregulation interacting with the sympathetic nervous system, and exerts a sympathomimetic effect. This action seems to be not adrenergic as there is no compensation of the catecholamine decrease due to isobarin administration.     

New Theoretical Schemes of the Simplest Chemical Oscillators

Based on the sufficient conditions for existence of concentration oscillations of the components of bicomponent reaction, all possible chemical reactions with two, three, or four intermediate stages proceeding via the mass-action expression are considered. About forty new schemes of chemical/biochemical oscillators are developed.