70 



NATURE, FORMATION, AND ACTIVITIES 



Tabi.e 22 

 Changes characterizing the three phases of streptomycin production (Hockenhull, 1960) 



meal are favorable for the production of the 

 antil^iotic. 



A detailed review of the biogenesis of 

 streptomycin has recently been published 

 by Hockenhull (H)()0). Three distinct phases 

 were recognized in the growth of the organ- 

 ism and formation of the antibiotic (Table 

 22). Although the surface growth of the 

 streptomycin-producing *S. griseus tended at 

 first to gwe higher yields than the growing 

 of the organisms under submerged condi- 

 tions (Thornberry and Anderson, 1948), the 

 latter method gradually became generally 

 employed. The first medium, recommended 

 by Waksman and Schatz (1945), consisted, 

 in grams per liter, of glucose (10), peptone 

 (5), meat extract (5), and sodium chloride 

 (5). Yeast extract, soybean meal, and dried 

 whole yeast were later used to replace the 

 meat extract. Glucose was usually the sugar 

 of choice, in amounts of 10 to more than 25 

 gm per liter. Certain strains were found to 

 be able to utilize, for streptf)mycin i)r(Kluc- 

 tion, fats, oils, or certain fatt.y acids in 

 place of glucose (Perlman and Wagman, 

 1952). 



Of the various nitrogen sources, L-proline 

 was found (Table 23) to be the most efTec- 

 ti\'e for streptomycin synthesis, although it 

 is only slowly utilized for the growth of the 

 organism. 



Streptomycin is basically a trisaccharide 

 with various substituent nitrogen groups. 

 By the use of isotopic carbon (C^), Hunter 

 and Hockenhull (1955) demonstrated that 

 the carbon of the glucose was distributed 

 evenly among the streptamine, streptose, 

 and the X-methyl-L-glucosamine portions 

 of the streptomycin molecule. The carbon 

 of the guanidine group was poorer in radio- 

 activity, thus indicating that this carbon 

 came from CO2 , as shown in Table 24 (see 

 also Xumerof et al., 1954). 



The effect of phosphate concentration on 

 streptomycin production is illustrated in 

 Table 25. In synthetic media, phosphate 

 exerted an effect on glucose breakdown and 

 on streptomycin biosynthesis. An excess of 

 phosphate caused an increased glucose con- 

 siunption. Increasing concentrations of phos- 

 phate first showed an increase, then a de- 

 crease in streptomycin synthesis. Arsenate 

 had a similar effect (Hockenhull et al., 1954). 



Hockenhull (1960) concluded that the 

 following factors favored streptomycin bio- 

 genesis: (1) high oxygen supply, (2) low 

 inorganic phosphate, (3) adec^uate glucose 

 concentration, and (4) nitrogen levels that 

 would not lead to high protein synthesis. It 

 was suggested that once the enzymes re- 

 (luired for streptomycin production have 

 Ijeen formed, further biosynthesis will take 



