[Stability of synthesis of type-II restriction endonucleases by streptomyces strains after their long-term storage].

Three streptomycete strains (Streptomnyces sp. 14, Streptomnzyces sp. 34, Streptomyces sp. 48)--producers of isoschisomers of restrictase Asull (Ssp34, Ssp48, Ssp14) were studied for the presence of synthesis of those site-specific endonucleases after long-term storage. Mycelium of streptomycete cultures was preserved at a temperature of -18 degrees C in 70% solution of glycerol for 10 years. It has been established that the studied strains preserved an ability to produce site-specific endonucleases of type II Ssp14, Ssp34 and Ssp48 after the long-term storage in the above conditions. Sporulation and synthesis of pigment have been also preserved. Plasmid DNA were found in Streptomyces sp. 14 and Streptomyces sp. 48. As to their electrophoretic mobility these DNA are analogous to those detected in these strains 10 years ago.