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.     

Larvae of related Diptera species from thermally contrasting habitats exhibit continuous up-regulation of heat shock proteins and high thermotolerance

A population of Stratiomys japonica, a species belonging to the family Stratiomyidae (Diptera), common name ‘soldier flies’, occurs in a hot volcanic spring, which is apparently among the most inhospitable environments for animals because of chemical and thermal conditions. Larvae of this species, which naturally often experience temperatures more than 40 °C, have constitutively high concentrations of the normally inducible heat-shock protein Hsp70, but very low level of corresponding mRNA. Larvae of three other species of the same family, Stratiomys singularior, Nemotelus bipunctatus and Oxycera pardalina, are confined to different type semi-aquatic habitats with contrasting thermal regime. However, all of them shared the same pattern of Hsp70 expression. Interestingly, heat-shock treatment of S. japonica larvae activates heat-shock factor and significantly induces Hsp70 synthesis, whereas larvae of O. pardalina, a species from constant cold environment, produce significantly less Hsp70 in response to heat shock. Adults of the four species also exhibit lower, but detectable levels of Hsp70 without heat shock. Larvae of all species studied have very high tolerance to temperature stress in comparison with other Diptera species investigated, probably representing an inherent adaptive feature of all Stratiomyidae enabling successful colonization of highly variable and extreme habitats.     

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.     

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.