title: Studies of protoplast fusion in Streptomyces chrysomallus.
abstract: Conditions for the regeneration of cells from protoplasts of Streptomyces chrysomallus, a producer of the peptide antibiotic actinomycin, are described. Regeneration of fusion products was most efficient at 27-30 degrees C on regeneration R2 medium (Okanishi et al., 1974) containing 0.25 M-sucrose. The addition of phosphate (150-300 mg 1(-1) to the medium and incubation at 23 degrees C proved to be optimal for the regeneration of individual strains. Highest recombination frequencies after protoplast fusion were obtained by fusing protoplasts in the presence of 45% (w/v) polyethylene glycol 6000. With strains that produce no, or little antibiotic, protoplasts must be present in excess in fusion mixtures in order to overcome inhibition of regeneration by the antibiotic-producing partner.
mesh_terms: D003609:Dactinomycin / Q000096:biosynthesis; D008970:Molecular Weight; D010710:Phosphates / Q000378:metabolism; D011092:Polyethylene Glycols / Q000494:pharmacology; D011523:Protoplasts / Q000378:metabolism / Q000502:physiology*; D011995:Recombination, Genetic / Q000187:drug effects; D012038:Regeneration; D013302:Streptomyces / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D013696:Temperature
chemical_list: D010710:Phosphates; D003609:Dactinomycin; D011092:Polyethylene Glycols; D013395:Sucrose