[Antibacterial spectrum of lisosubtilin G10X]. / Antibakteria'lnyi spektr lizosubtilina G10X.

Data on the antibacterial spectrum of lysosubtilin G10X, a preparation of lytic enzymes from Bacillus subtilis SK-52 are presented. Lysosubtilin was active against grampositive and gramnegative pathogenic bacteria. When it was used as a substrate of live lyophilized microbial cells the highest lysis levels were observed in B. brevis, B. cereus, B. pumilis, B. subtilis and S. faecalis. Preincubation of the substrate in acid media mainly increased the levels of the lysis by enzyme preparation. Sometimes the increase was very high (B. sphaericus, B. subtilis 720, E. coli K12 and MRE-600). Such a preincubation provided cell lysis in some strains not liable to the effect of lysosubtilin (B. cereus 1312, C. renale, M. luteus, S. aureus KP, 800, 805 and 126001, S. pyogenes 291). An increase in the lysosubtilin concentration in the reaction mixture in the majority of the cases did not provide favourable results. However, some strains resistant to the preparation at a concentration of 1000 units/ml were lysed with its 10 times higher doses. An increase in the lysis level was also achieved with increasing the time of the incubation with the enzyme preparation. Proceeding from the preparation antibacterial spectrum it is possible to recommend it for treatment of diseases in agricultural animals. Its use in veterinary was a success.

[Lysosubtilin G10x--a new antimicrobial agent for treatment and prophylaxis. Physico-chemical properties]. / Lizosubtilin G10x--novyi antimikrobnyi agent lechebno-profilakticheskogo naznacheniia. Fiziko-khimicheskie svoistva.

Lysosubtilin G10x, a lytic enzyme from Bacillus subtilis SK-52 was studied with respect to its physico-chemical properties such as effect of optimal conditions and stability. The maximum activity of the enzyme was observed in phosphate buffer at a concentration of the buffer mixture equal to 0.004 M, pH 7.2 and the temperature of 37-50 degrees C. Aqueous solutions of lysosubtilin G10x were stable at pH 5-9. The lytic activity of the enzyme aqueous solutions rapidly lowered at a temperature above 50 degrees C. The ions of some metals, especially those of mercury, copper and ferrous iron inhibited the enzyme. Lysis activation was recorded in the presence of surface active substances such as sodium dodecylsuphate, tritone X-100 and certain twins. Comparison of the findings with the results of our previous studies on the lytic properties of enzymes from other strains of B. subtilis showed that irrespective of the strain lysosubtilins were sensitive to changes in the medium ionic strength, they were mostly active in neutral solutions of low ionic strength, their activity was inhibited by heavy metal ions and they were stable within wide ranges of pH. This should be taken into account in practical use of lysosubtilin G10x.

[Composition of the regulators of bacterial autolysis]. / Sostav reguliatorov avtoliza bakterii.

This work was aimed at studying the composition of agents regulating bacterial autolysis and isolated from the lysate of Bacillus subtilis 402, B. subtilis R2 and Micrococcus lysodeikticus biomass by extraction with 5% TCA followed by precipitation from the extract with 5 volumes of isopropanol. Fractions activating bacterial autolysis and fractions inhibiting it were found in all of the preparations after separation on Acrylex P-60. Fractions with a molecular mass below 12,600 D activated the autolysis whereas fractions with a molecular mass above 18,400 D inhibited it. The activity of fractions inhibiting the autolysis decreased while that of fractions activating the autolysis increased in the regulating agents isolated from B. subtilis cultures with the aging of the latter. The capability of the fractions to activate the autolysis correlated with the content of amino groups and phosphate in them whereas the capacity to inhibit the autolysis correlated with the content of reducing sugars in the fractions. The preparation of the fraction which activated the autolysis from B. subtilis R2 contained 18 amino acids with the predominance of alanine, glutamic acid, lysine and phenylalanine. Apparently, the regulating properties of the preparations are created with the aid of teichoic acids as well as peptidoglycan and protein fragments associated with the acids.

[Effect of regulators on bacterial autolysis]. / Vliianie reguliatorov na avtoliz bakterii.

The aim of this work was to study the effect of autolysis regulators (the fraction of microbial teichoic acids) on the rate of autolysis and the activity of bacterial extracellular lytic enzymes. The regulators of autolysis isolated from 23 cultures belonging to 10 microbial species regulated the rate of autolysis in Bacillus, E. coli and Streptococcus lactis. The regulators either activated or inhibited autolysis depending on the substrate (of a bacterium to be subjected to autolysis). The quantitative dependence of the autolysis rate on the regulator concentration was specific for each pair 'regulator--substrate'. The regulatory properties of the fraction of teichoic acids varied depending on the age of a culture from which they had been isolated. The regulators of autolysis, with an exception of the preparation from E. coli, inhibited the activity of B. subtilis extracellular lytic enzymes in the course of their action on E. coli cells. The possibility for using the regulators of autolysis in microbiological processes is discussed.

[Isolation and characterization of the lytic enzyme from Bacillus subtilis 797]. / Vydelenie i kharakteristika liticheskogo fermenta iz Bacillus subtilis 979.

The isolation procedure and some properties of the lytic enzyme produced by Bacillus subtilis 797 and capable of hydrolyzing the E. coli K-12 cells are described. Using hydrophobic chromatography on DNP-hexamethylene diamine Sepharose 4B and ion-exchange chromatography on DEAE-cellulose, a highly purified enzyme preparation with mol. weight of 28000, pI 8.2 has been obtained. The amino acid composition of the enzyme has been determined: Asp--37, Thr--17, Ser--34, Glu--15, Pro--14, Gly--17, Ala--36, Val--28, Met--4, Ile--11, Leu--17, Tyr--9, Phe--4, Lys--18, His--5, Arg--4. The enzyme is inhibited by a specific inhibitor of serine proteinases--benzylsulfonylfluoride, and is insensitive to EDTA and iodoacetic acid. The lytic enzyme has a proteolytic activity and splits the peptide substrate of bacterial serine proteinases--p-nitroanilide benzyloxycarbonyl-L-analyl-L-alanyl-L-leucine; the maxima for both activities lie within the pH range of 7.8-8.5. The lytic protease has the highest stability at pH 6-10. In some of its properties the enzyme is similar to serine proteinase from Bac. subtilis, i. e. subtilisins.

[Properties of a preparation of lytic enzymes from a culture of Bacillus subtilis]. / Izuchenie svoistv preparata liticheskikh fermentov iz kul'tury Bacillus subtilis

The effect of pH, temperature, various salts and other compounds on the activity of the preparation of lytic enzymes from the culture of Bacillus subtilis (lyzosubtilin) was investigated. The preparation was shown to be active in neutral solutions of low ionic strength at 30-50 degrees C. The salts of magnesium, manganese, copper, zinc, lead, mercury, aluminium and iron as well as Tris-buffer and Triton X-100 inhibited lyzosubtilin whereas lactic acid activated it. At 30 degrees C the preparation was stable within the pH range of 5 to 10. Its incubation for 60 min at 60 degrees C resulted in the loss of 50% activity. Lyzosubtilin lyzed cells of gram-positive and gram-negative bacteria, yeast and fungi.