[Isolation and primary characteristics of elastase from a clinical strain of Pseudomonas aeruginosa]. / Poluchenie i pervichnaia kharakteristika élastazy iz klinicheskogo shtamma Pseudomonas aeruginosa.

The homogeneous preparation of elastase has been obtained from P. aeruginosa clinical strain. The molecular weight of the isolated enzyme is 33,000 daltons, and its isoelectric point is 6.8. Two media manufactured in this country (dialyzed bovine heart hydrolysate and a dried semisynthetic medium) ensuring good production of the enzyme have been proposed. The optimum time for the cultivation of the producer strain (30-40 hours) has been established. Elastase has been shown to be widely spread among P. aeruginosa clinical strains.

[Isolation of different variants of Pseudomonas aeruginosa anatoxin and their characteristics]. / Poluchenie razlichnykh variantov anatoksina Pseudomonas aeruginosa i ikh kharakteristiki.

The conditions for the detoxification of the crude preparations of P. aeruginosa exotoxin A, obtained by the cultivation of strain PA-7 in Martin's broth, have been studied, and the schemes for obtaining nontoxic, stable, specifically antigenic preparations of toxoid from exotoxins A with different degrees of purification have been developed. Toxoid obtained by formalin treatment on the level of a crude preparation with its subsequent purification and additional detoxification with formalin in the presence of lysin has been shown to possess high immunogenic potency. The preparation has been found to induce immune response and to ensure the protection of experimental animals challenged not only with the lethal dose of exotoxin A, but also with P. aeruginosa toxigenic and protease-producing strains.

[Characteristics of the activation of type E. Cl. botulinum toxins]. / Nekotorye osobennosti aktivatsii botulinicheskogo toksina tipa E.

Molecular changes occurring in type E. Cl. botulinum single-chain toxin as the result of treatment with trypsin under different conditions were studied. The intensity of activation of the precursor and the ensuing changes of its molecular structure were found to depend on the pH of the medium. At pH 6.0 complete activation induced by the trypsin treatment of the single-chain toxin coincided with complete break-up of the polypeptide chain, while at pH 5.0 the toxin was completely activated before all its molecules could acquire the double-chain structure. At pH 4.5 no increase in the potency of the toxin was registered even in those cases when break-up of the molecules was as pronounced as by the moment of complete activation of the toxin at pH 5.0. These data suggest that activation is not direct consequence of break-up of the peptide bond responsible for the formation of a double-chain molecule. Trypsin-induced activation seems to be linked with the splitting of some peptide bond in one of the end areas of the molecule.

[Isolation and properties of highly purified C1. botulinum toxin type E]. / Vydelenie i nekotorye svoistva vysokoochishchennogo botulinicheskogo toksina tipa E.

A new method of isolation of highly purified Cl. botulinum toxin of E type from the cultural fluid of strain 188 centrifugates was developed. The method allows to isolate the toxin both in a precursor and in activated forms with a yield of 10--15%. The method includes fractionation by ammonium sulfate, ultrafiltration and subsequent column chromatography on DEAE-cellulose, Sephadex G-200 and DEAE-Sephadex A-50. The preparations were found homogeneous during polyacrylamide gel electrophoresis and immunoprecipitation in agar with antitoxic horse serum. The potential specific toxicity of the preparations is 1--1,2.10(7) DLM/mg of protein. The molecular weight of the toxin is about 160 000; the molar extinction coefficient is equal to 278 nm. The isoelectric point lies around pH 6.0. The highly purified Cl. botulinum toxin of E type was found stable upon storage.

[Patterns in the formation of proteolytic enzymes by different strains of C1. botulinum type F]. / Nekotorye zakonomernosti obrazovaniia proteoliticheskikh fermentov razlichnymi shtammami C1. botulinum tipa F

The authors studied regularities attending the accumulation of proteolytic enzyme and toxin by C1. botulinum, type F, strains in the medium. Strains No. 470, 200, 76, 55 proved to possess caseinolytic capacity, whereas strains Eklund and Craig were "nonproteolytic". C1. botulinum strain, type F, medium and growing conditions providing a high yield of proteolytic enzymes were selected. Some properties of proteolytic enzyme of strain No. 470 were studied.