[Comparative study of the phage sensitivity of actinomycetes and their Nocardia-like variants]. / Sravnitel'noe izuchenie fagochuvstvitel'nosti nekotorykh aktinomitsetov i ikh nokardiopodobnykh variantov.

The work was aimed at studying the resistance of three streptomycetes (Streptomyces chrysomallus, S. azureus and S. roseoflavus var. roseofungini) and their spontaneous Nocardia-like variants lacking aerial mycelium and spores against nine polyphages isolated mainly from soil. Some Nocardia-like variants were found to differ from their parent cultures in the resistance against certain actinophages. S. chrysomallus VKM Ac-590 and Ac-628 variants lost resistance against the phages. S. azureus VKM Ac-719 and S. roseoflavus var. roseofungini VKM Ac-770 variants became resistant to the phages. The changed phage resistance of the streptomycetes and their Nocardia-like variants was attributed to the disorganised process of adsorption (8 and 7%, respectively, against 70 and 90% for the parent strains).

[Characteristics of defective lysogeny in Streptomyces chrysomallus]. / Ob osobennostiakh defektnoi lizogenii Streptomyces chrysomalus.

When Streptomyces chrysomallus 2703 grows on solid media, lytic zones appear in the form of negative colonies which are not caused by the virulent phage. The material from these colonies and the cultural broth of S. chrysomallus 2703 were examined by electron microscopy. Four different morphological types of particles were revealed, three of which were defective phage particles (tails). Particles of the fourth type had a regular hexagonal shape and a diameter of 200A. The particles prevailed in all of the preparations. Their origin is discussed. S. chrysomallus in considered as a poly- and defective lysogenic culture.

[Actinophage restriction and modification by Streptomyces hygroscopicus and Str. levoris cultures]. / O restriktsii i modifikatsii aktinofagov kul'turami Streptomyces hygroscopicus i Str. levoris.

The capability for restriction and modification was studied in the cultures of Streptomyces hygroscopicus 0477 and Streptomyces levoris 1331, 2340, 2144 toward the active against them temperate phage and three polyphages. All these cultures were found to be capable of the restriction and modification of the temperate phage. Certain differences in the restriction and modification were established between Str. levoris 1331 and the two other cultures of this species. The culture 1331 could modify the temperate phage only with respect to itself rather than the two other cultures. The phage growing on the culture 1331 was restricted not only by the culture 0477, but also by the strains of Str. levoris 2340 and 2144. At the same time, the phage growing on the strains 2340 and 2144 gave the identical effectiveness of inoculation on any of these cultures, as well as on the culture 1331, and was restricted to the same degree by the culture 0477. One of the examined polyphages 14/3 was not restricted by any of the tested cultures. Two other polyphages SH4 and p4 were restricted only by the culture 2144. However, the modification by this culture was not observed. Among the studied cultures of Str. levoris, the culture 2144 was most capable of the restriction.

[Changes in the actinophage sensitivity and resistance of a culture of Actinomyces griseus and its variants]. / Izmeneniia chuvstvitel'nosti i ustoichivosti kul'tury Actinomyces griseus i ee variantov k aktinofagam.

Susceptibility and resistance of the culture of Actinomyces griseus 15 and its variants to actinophages was studied. Variants different from the parent culture in their susceptibility or resistance to certain phages can arise as the result of spontaneous variability and lysogenization. The culture of Actinomyces griseus 15 resistant to nine polyphates was found to be able to adsorb them. The mycelium of Act. griseus 15 was shown to contain receptors for a page to which it was susceptible different from those for a polyphage to which it was resistant though capable of adsorbing it.

[Phenomenon of temperate phage restriction and modification in a lysogenic culture of Streptomyces hygroscopicus]. / O iavlenii restriktsii i modifikatsii umerennykh fagov lizogennoi kul'tury Streptomyces hygroscopicus.

Temperate phages were isolated from the lysogenic culture of Streptomyces hygroscopicus 0485 in the indicator cultures of Str. hygroscopicus 0477 and Str. levoris 1331. The phages were found to be identical in the morphology of particles and serological properties. The phenomenon of cross limitation, by the culture of Str. hygroscopicus 0477, of the phage growing on the culture of Str. levoris 1331, and vice versa, was established. At the same time, the phages were shown to be modified by the host cell.

[Lysis from without of a culture of Actinomyces griseus--producer of the antibiotic kormogrizein]. / Iavlenie lizisa izvne u kul'tury Actinomyces griseus--produtsenta antibiotika kormogrizina.

A polylysogenic culture of Actinomyces griseus 15 producing the antibiotic cormogrisin is sensitive to actinophages, denoted as types 15 I, 15 II and 15 III, which are the virulent mutants of its temperate phages. In certain cases, the variants of Act. griseus 15, obtained by selection and resistant to the phages types 15 I and 15 II, can undergo lysis-from-without by these phages. A study of the mechanisms involved in this phenomenon has shown that the lytic activity is entirely eliminated if the phages have been a titre of 10(9) and higher. The lytic activity is entirely eliminated if the phages have been treated with a specific serum or inactivated by UV. The variants resistant to phage 15 I can adsorb this phage and undergo lysis-from-without at a high multiplicity of infection if only the age of the variant does not exceed 13 hours. The variants resistant to phages 15 I and 15 II can undergo lysis-from-within under the action of phage 15 III. The variants resistant to this phage have acquired this resistance as a result of lysogenization. They have entirely retained the ability to adsorb phage 15 I, but their ability to absorb phage 15 III is much lower. Therefore, the rate of mycelium growth is only slightly inhibited, but the lysis of the culture is not observed, under the action of phage 15 III having titres of 10(9) and 10(10).

[Lysogeny of the Streptomyces hygroscopicus culture reducing the antibiotic turimycin and some characteristics of its temperate phage]. / Lizogeniia kul'tury Streptomyces hygroscopieus--produtsenta antibiotika turimitsina i nekotorye osobennosti ee umerennogo faga

The culture of Streptomyces hygroscopicus JA 6599 producing antibiotic turimycin was found to be lysogenic. Four variants produced from this culture by the inducing with acridine orange did not synthesize the antibiotic but were also lysogenic. Temperate phages isolated from the parent culture and from its four variants were identical by their main biological properties. Therefore, production of turimycin is not controlled by the isolated temperate phage.

[New phages of a polylysogenic culture of Actinomyces griseus]. / Novye fagi polilizogennoi kul'tury Actinomyces griseus

The culture of Actinomyces griseus 15 was found to have a more complicated phage composition than it was supposed earlier. A new virulent mutant B has been isolated, which differs by its properties from the phage of Act. griseus 15, type I, isolated earlier. Phage lysates of the virulent mutants originating from different temperate phages of Act. griseus 15. Therefore, the culture of Act. griseus 15 is polylysogenic, defective lysogenic and contains at least three different phages.