[Actinophage restriction and modification by Streptomyces hygroscopicus and Str. levoris cultures]

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.