Isolation of nisin from native solution and its purification on cationites]

It was found possible to use organic sorbents and in particular carboxylic cationites for isolation of nisin from the fermentation broth filtrate and its purification. Nisin is known as a polypeptide antibiotic applied as a preservative. The sorbents were shown to have high exchange capacities by the isolated substance and mechanical strength and resistance. They also proved to be highly stable.     

Ability to induce an experimental hypercholesteremia in rats with reduced ability for drinking conditioning

A diet rich in cholesterol caused individual differences in its accumulation in the blood of unbred male rats. High sensitivity of rats to hypercholesterinemia is reciprocally related to drinking conditioning.     

The role of guanidine groups of arginine residues of Na, K-ATPase and glutamate dehydrogenase in an interaction with cholesterol

Cholesterol was studied in experiments in vitro for its effect on the activity of Na, K-ATPase of the synaptic brain membranes of rats and a crystalline preparation of glutamate dehydrogenase from the liver mitochondria of a bull. Cholesterol decreased the activity of the above enzymes. When blocking guanidine groups of arginine residues of Na, K-ATPase and glutamate dehydrogenase the inhibiting action of cholesterol was absent. The obtained data evidence for the possibility of a direct interaction of cholesterol with membrane enzymes as well as for the important significance of guanidine groups of arginine residues of proteins in the process.     

Interaction of steroid hormones with glutamate dehydrogenase]

The inhibitory action of sex hormones on the glutamate dehydrogenase activity is due to their binding to the enzyme protein. No binding of sex hormones to glutamate dehydrogenase is observed in the presence of L-amino acids, preventing the enzyme dissociation. Under those conditions the enzyme sensitivity to the inhibitory action of the hormones sharply decreases.     

The ecology and prevalence of arboviruses on the territory of the Saratov Region

The territorial spread of Tahyna, Batai, Sindbis, West Nile fever and Crimean-Congo hemorrhagic fever viruses throughout the Saratov region in 1998 - 2000 was analyzed. The characteristics of the epizootic activity of the natural foci of these arboviruses in different landscape zones (temperate forest-steppes, steppes and semi-deserts) were calculated. The species composition of small mammals, the natural reservoirs of the causative agents of arbovirus infections, was determined.     

Purification of waste water from the antibiotic-producing industry using synthetic sorbents]

It was shown possible to use Polysorb S-40/100, a synthetic sorbent, for after treatment of sewage from antibiotic production. Kinetic relationships between the sorption and sorbent regeneration are presented.     

Determination with a microelectrode of membrane potential of giant human erythrocytes obtained by La(3+)-induced fusion

The effect of La3+ on the fusion of erythrocytes of blood stored for a week at +4 degrees C was studied. It was shown that the fusion of erythrocytes begins after one day of storage of blood. The most intensive fusion of erythrocytes was observed on day 4 of blood storage. As a result, giant cells with a size of 100 microns and more arise. The electrical potential of giant cells was measured using a microelectrode and was -6.6 +/- 1.5 mV.     

Effects of parathyroid hormone and parathyroid hypertensive factor on myocardial mechanical properties in normotensive rats

After a 10-minute incubation, both the parathyroid hypertensive factor (PHF) and parathyroid hormone (PTH) reduced myocardial contractility and accelerated myocardial relaxation. Effects of the PTH and PHF on myocardial inotropic characteristics were of opposite directions.     

Inhibition of lipoprotein lipolysis by polyarginine and evaluation of the mechanism of its interaction with lipoprotein lipase

It was found that polyarginine (Mr 40 000-60 000) is a strong inhibitor of the lipoprotein lipase activity in vivo and in vitro. The inhibitory effect in vivo was observed after a single intravenous injection of 0.85-3.5 mg/kg to rabbits, that in vitro at the polypeptide concentration of greater than or equal to 2.5 micrograms/ml. Within the first few hours after intravenous injection of polyarginine hyperlipidemia occurred with an obvious increase in the plasma triglyceride and VLDL fractions and a slight decrease of the LDL and HDL fractions. These changes typical for reduced lipoprotein lipolysis were due to the formation of a polyarginine-heparin complex, on the one hand, and to the formation of a polyarginine-enzyme complex devoid of the lipolytic properties, on the other. The inhibitory effect of polyarginine on lipoprotein lipase is related to the whole polypeptide molecule or its large fragment, since arginine and metformine (bi-guanidine compound) have no effect on the enzyme activity.