[Pigment and antibiotic substance contained in the spores of Actinomyces streptomycini B-6]. / Pigment i antibioticheskoe veshchestvo, soderzhashcheesia v sporakh Actinomyces streptomycini B-6

The antibiotic activity and fractional composition of the supernatant of the homogenate of Actinomyces streptomycini B-6 spores were investigated. The homogenate supernatant was of yellow colour and showed antibiotic activity when used as the test-organism of the culture St. aureus 209. The antibiotic activity was associated not with the homogenate pigment but with the colourless substance referring to streptomycins which was contained in spores.

[A serine proteinase from Thermoactinomyces vulgaris, strain INMI-4a]. / Serinovaia proteinaza Thermoactinomyces vulgaris sht. INMI-4a.

A serine proteinase was isolated from the cultural filtrate of the thermophylic actinomycet Thermoactinomycet vulgaris, strain INMI-4a. The purification procedure included affinity chromatography on bacitracin-Sepharose, ion-exchange separation on aminosilochrome, and gel-filtration on Sephadex G-25, resulting in a 194-fold purification and the 55% yield of the enzyme. The molecular weight of the enzyme as determined by polyacrylamide gel electrophoresis in the presence of Na-SDS as well as by gel-filtration on Sephadex G-75 is equal to 28 000; the amino acid composition is: Lys11, His4, Arg5, Asp33, Thr22, Ser24, Glu16, Pro16, Gly30, Ala38, Cys1-2, Val20, Met1, Ile14, Leu8, Tyr16, The4, Trp6-7. The isoelectric point lies at pH 8--9; the pH optimum for the peptide substrate hydrolysis is Z-L-Ala-L-Ala-L-Leu-pNA is at 8.2. The enzyme is stable at pH 7--9. The temperature optimum of the proteolytic activity lies at 55 degrees; however, the enzyme is stable to heating for 1 h at 37 degrees. The proteinase is completely inactivated by the serine proteinase specific inhibitors--phenylmethylsulphofluoride and the protein inhibitor IT-AjT from Actinomyces, as well as by p-chloromercuribenzoate. The enzyme shows lytic activity against the cells of E. coli, Micrococcus lysodeicticus and of the yeasts. The Thermoactinomyces vulgaris serine proteinase, being definitely different from the serine proteinases from Actinomyces griseus, also reveals specific differences when compared to bacterial serine proteinases, e. g. subtilisins. There are some indications to the enzyme relationship with the family of carboxypeptidase Y-like serine proteinases.

[Factors causing lysis of an Actinomyces rimosus culture, the producer of the antibiotic, oxytetracycline]. / O faktorakh, vyzyvaiushchikh lizis kul'tury Actinomyces rimosus-produtsenta antibiotika oksitetratsiklina

The lysis of Actinomyces rimosus producing oxytetracycline during its mass growth can be caused by two factors which were separated by differential centrifugation. The first factor is phage particles of a temperate phage produced by the culture; they are incapable of growth but may induce the lysis. The phage particles treated with low pH and a temperature of 70 degrees C lose the lytic activity. The second factor is a lytic enzyme produced under the control of the temperate phage during its induction; it seems to consist of at least two enzymes, a lytic enzyme and a proteolytic enzyme.