[Effect of nitrogen source on growth of Arthrobacter simplex and its biosynthesis of cholinesterase].

The effect of organic and inorganic forms of nitrogen on biomass accumulation and cholinesterase synthesis was studied with Arthrobacter simplex var. cholinesterasus. The culture assimilates nitrogen of ammonium compounds better than other forms of inorganic nitrogen; the best nitrogen source for biosynthesis of cholinesterase is ammonium phosphate.

[Use of hydropyrite in the chemiluminescent determination of iron-porphyrin proteins].

Hydropyrite was found to be a suitable reagent which may be used in chemiluminescent reactions for determination of iron-porphyrin proteins.

[Radiometric study of the decarboxylating activity of desert soil microflora].

Employment of growth media containing salts of organic acids, labelled with 14C, gave a rapid and intensive signal concerning the decarboxylating activity of microorganisms from desert soils. The value of the signal was higher than that during the decomposition of uniformly labelled glucose. The results of these studies would help to select the optimal growth medium for carrying out exobiological experiments.

[Activity of microorganisms decomposing cholesterol].

The rates of cholesterol decomposition was compared among cell suspensions of different microorganisms. Fifty seven cultures were studied: 2 strains of actinomycetes, 23 strains of proactinomycetes, 22 strains of mycobacteria, and 10 strains of bacteria. During four hours of incubation, 11 strains virtually did not decompose cholesterol at all, 10 strains decomposed it by up to 20 per cent, 21 strains by 20 to 70 per cent, and 15 strains by 70 to 100 per cent.

[Decomposition of cholesterol by Achromobacter candicans].

The decomposition of cholesterol by the cell suspensions of Achromobacter candicans 42 and by the cell-free extracts of this bacterium was studied. The decomposition of cholesterol in the presence of the wet biomass during four hours of the incubation was 72.5 percent, and with the cells that were preliminarily lyophilized or treated by acetone 49.