High-frequency fusion of Streptomyces parvulus or Streptomyces antibioticus protoplasts induced by polyethylene glycol

Abstract

Conditions were established for the regeneration of protoplasts of S. parvullus and S. antibioticus to the mycelial form. Regeneration was accomplished with a hypertonic medium that contained sucrose, CaCl2, MgCl2 and low levels of phosphate. High-frequency fusion of protoplasts derived from auxotrophic strains of S. parvullus or S. antibioticus was induced by polyethylene glycol 4000 (42%, wt/vol). The frequency of genetic transfer by the fusogenic procedure varied with the auxotrophic strains examined. Fusion with auxotrophic strains of S. parvullus resulted in the formation of true prototrophic recombinants. Similar studies with S. antibioticus revealed that both stable prototrophic recombinants and heterokaryons were formed.