[Thrombolytic activity of Bacillus mesentericus at different conditions of nitrogen nutrition of a culture]. / Tromboliticheskaia aktivnost' u Bacillus mesentericus pri razlichnykh usloviiakh azotnogo pitaniia kul'tury.

The work is concerned with studying the effect exerted by different sources of nitrogen nutrition on the biosynthesis of proteinases with a thrombolytic activity by a variant of Bacillus mesentericus, strain 64, obtained with the aid of analytical selection. Protein substrates taken as a nitrogen source stimulate the synthesis of proteinases by the bacterial culture. These enzymes have a high caseinolytic and thrombolytic activity, and the level of their activity correlates with the amount of a protein substrate added to the medium. Ammonium acetate and succinate are the best stimulants for the formation of proteinases when the salts of mineral and organic acids are used as a source of nitrogen nutrition. In that case, the enzymes have a high thrombolytic activity and a low caseinolytic activity. A semi-synthetic medium with the aforementioned nitrogen-containing compounds as a source of nitrogen nutrition is proposed for the synthesis of thrombolytic proteinase by the variant of B. mesentericus.

[Substrate specificity of enzymes from Bacillus mesentericus]. / Substratnaia spetsivichnost' fermentov Bacillus mesentericus.

The proteolytic enzymes of the sporogenous Bacillus mesentericus strains 64 and 8 were tested for their ability to hydrolyse different protein substrates. The enzymes were isolated using affinity chromatography on bacillichine-silochrome, and eluted with 25% isopropanol in 0.05 M Tris-HCl buffer, pH 8.0-8.4, containing 0.01 M CaCl2. Casein, hemoglobin, elastin, albumin and synthetic peptides, Z-L-Ala-Ala-Leu-pNa and Z-L-Ala-Gly-Leu-pNa, were used as substrates. The activity of esterase was assayed in terms of indophenyl acetate cleavage. The proteinases were compared with terrilytin, a commercial preparation. The proteinase of strain 64 was active in the hydrolysis of casein, hemoglobin and elastin; its specificity was close to that of terrilytin. The proteinase of strain 8 differed from them in a higher thrombolytic and fibrinolytic activity, and had a high esterase activity.

[Effect of inhibitors and cations on the proteolytic activity of Bacillus mesentericus]. / Vliianie ingibitorov i nekotorykh kationov na proteoliticheskuiu aktivnost' Bacillus mesentericus.

The effect of some inhibitors and bivalent metal cations (Mn2+, Ca2+, Fe2+, Zn2+, Mg2+, Co2+ and Cu2+) on the proteolytic activity of two Bacillus mesentericus strains (strain 8 and strain 64 M-variant) was comparatively studied. The both enzymes were shown to be serine proteinases, but the proteinase of strain 64 was also a metal-dependent enzyme. Metal ions exerted no essential effect on the proteinase of strain 8. Ca2+ and Mg2+ ions stimulated the proteinase activity of strain 64 whereas Fe2+ and Zn2+ ions inhibited it in the case of three substrates. Therefore, the two proteinases are different.

[Fibrinolytic activity of natural variants of Bacillus mesentericus]. / O fibrinoliticheskoi aktivnosti estestvennykh variantov Bacillus mesentericus.

The natural variability of the ability to synthesize proteinases by Bacillus mesentericus 64 was studied. The population of this strain was shown to be heterogeneous. Three types of variants (S, M and P) differed in the morphology of their colonies and in the culture characteristics from the typical colonies of the parent strain. The caseinolytic activity of the M variant was three times as high as that of the parent strain, and it also had an elevated fibrinolytic activity and a high rate of blood thrombolysis in experiments in vitro. The rate of proteinase synthesis correlated with the morphological types of sporogenic bacteria.

[Fibrinolytic activity of Bacillus mesentericus strains]. / O fibrinoliticheskoi aktivnosti nekotorykh shtammov Bacillus mesentericus.

Two Bacillus mesentericus strains with a high activity of proteolytic enzymes having the thrombolytic action were selected from a group of its collection strains. The effect of different carbon sources on the synthesis of proteases was studied. A growth medium containing potato broth (10%), peptone (0.5%) and lactose (0.5%) allowed one to obtain a cultural broth dissolving human blood clots within 2.5 to 3 hours in experiments in vitro.

[Formation of dextranases by mycelial fungi and actinomycetes]. / Obrazovanie dekstranaz mitselial'nymi gribami i aktinomitsetami

The dextranase activity of cultures of mycelial fungi of different genera and actinomycetes from the Chromogenes species of the Actinomyces genus was studied. About one third of the mycelial fungi and 8% of actinomycetes showed dextranase activity. The resulting extracellular dextranases demonstrated on endotypic pattern of action on the substrate. Actinomycete dextranases were several times more active than fungal dextranases and exhibited a significant activity in the neutral and weakly alkaline medium. Highly productive strains that are promising as dextranase producers were isolated.