290 PHYSIOLOGY OF THE FUNGI 



physiology of penicillin-fast bacteria vao^y be abnormal (Bellamy and 

 Klimek 1948). Penicillin is most active against young cells, in that it 

 inhibits the process of cell division. For papers on the mechanism of 

 penicillin action see Cavallito et al. (1945), Chain and Diithie (1945); 

 Bailey and Cavallito (1948) ; and a series of papers by Pratt and Dufrenoy 

 (1949). 



Table 52. The Production of Penicillin in the United States for the Years 



1943 TO 1948 

 A unit of penicillin is 0.6 ^g. (Coghill and Koch, Chem. Eng. Neivs 23, 1045; Lee, 

 Ind. Eng. Chem. 41, 1949. Published by permission of the American Chemical 

 Society.) 



Year Billions of Units 



Further details may be found in the following selected references. For 

 a concise authoritative account of all phases of penicillin, see Foster 

 (1949). The medical aspects of penicillin therapy are discussed by 

 Fleming (1949). The chemistry of penicillin is covered in the monograph 

 edited by Clarke et al. (1949). The early history of penicillin is pre- 

 sented by Chain and Florey (1944) and Waksman (1947). 



Streptomycin. This antibiotic was discovered in Waksman's labora- 

 tory in 1943, and three years later, commercial production of this drug 

 began. Streptomycin is synthesized by some isolates of Streptomyces 

 griseus. The techniques used in industry resemble those used for the 

 production of penicillin in submerged aerated culture. Streptomycin 

 is adsorbed on activated carbon as the first step in isolation and purifica- 

 tion. In contrast to penicillin, streptomycin is a basic compound. The 

 production of streptomycin in the United States increased from 1,175 

 billion units in 1946 to 37,710 billion units in 1948 (Lee, 1949). The 

 chemistry of streptomycin is reviewed by Lemieux and Wolfrom (1948). 



Streptomycin is mainly active against Gram-negative bacteria and 

 certain acid-fast organisms, including Mycohacterium tuberculosis. This 

 drug controls many pathogens which are unaffected by penicillin. Organ- 

 isms exposed to streptomycin frequently become fast. Indeed, some 

 bacteria have been reported to become dependent upon the drug. 



The composition of the medium influences streptomycin production. 

 Soybean meal appears to be a suitable source of nitrogen for commercial 

 production (Rake and Donovick, 1946). The influence of carbon and 

 nitrogen sources in synthetic media has been studied by Dulaney (1948, 

 1949). These results may be summarized as follows: Glucose and man- 



