68 



NATURE, FORMATION, AND ACTIVITIES 



liberation of micleic acids and monoamine 

 acids into the medium. When alanine is 

 present in the medium, basic amino acids and 

 nucleic acid metabolites appear in the first 2 

 days; on the following day the concentra- 

 tion of histidine and nucleic acid metabolic 

 products diminishes. Arginine and lysine 

 remain on the same level. Inositol and sub- 

 stances containing a guanidine grouping 

 exert a marked effect upon the biosynthesis 

 of streptomycin (Egorov, 1959). 



Shaposhnikov et al. (1959) made a study 

 of the formation of streptomycin in synthetic 

 media containing proline, or histidine with 

 lysine or proline, succinimide, or succina- 

 mide. The yield of antibiotics on these media 

 w^as 74 to 84 per cent of that on soybean 

 meal medium. Oxyproline was found to be a 

 unique source of nitrogen, contributing to 

 the growth of the actinomycete, while only 

 weakly stimulating the formation of strepto- 

 mycin (Table 19). When this amino acid was 

 added to a medium already containing the 

 basic amino acids, growth was favored but 

 the antibiotic yield was lowered (Table 20). 



Schaiberger (1959) examined in detail the 

 mechanism leading to the biosynthesis of 



Table 19 

 Maximal mycelial weights and quantities of strep- 

 tomycin on media with pyrrole compounds 

 (Shaposhnikov et al., 1959) 



Table 20 

 Maximal mycelial weights and quantity of strepto- 

 mycin on media with histidine, lysine, and pyr- 

 role compounds (Shaposhnikov et al., 1959) 



* Control I contains an inorganic nitrogen 

 source. Control II contains an organic nitrogen 

 source. Both controls have sovbean meal added. 



* Basic medium: 2% glucose, 0.39( (NH4)2S04 , 

 0.25% NaCl, 0.05% KH.,P04 , 0.3% CaCO^ , distilled 

 water. Soybean meal, amino acids, or other pyr- 

 role compounds added on basis of 112 mg of ni- 

 trogen per 100 ml of medium. 



streptomycin. He used a high streptomycin- 

 producing culture of *S. griseus (S-f-) and a 

 mutant without streptomycin (S — ) derived 

 from it. The S— culture was asporogenous 

 and lacked the ability to synthesize strepto- 

 mycin; however, its rates of growth and of 

 sugar utilization were double those of the 

 S4- strain. The nutritional reciuirements for 

 growth and streptomycin synthesis by the 

 S+ culture included glucose, a suitable 

 inorganic nitrogen source (ammonia), and 

 six mineral salts (MgS04 , FeS04 , ZnCl,. , 

 CaCOa, K2HPO4, and NaCl). These nu- 

 trients also satisfied the growth require- 

 ments of the S— strain. Resting mycelial 

 suspensions confirmed the essentiality of the 

 salts for streptomycin synthesis, with the 

 exception of KiHP04 . Exogenous addition 

 of phosphate inhibited streptomycin syn- 

 thesis by resting cells. When used as the sole 

 nitrogen source in a mineral salts-glucose 

 medium, proline and the amino acids closely 

 related metabolically (asparagine, histidine. 



