l'll\S10l,(HiV 



115 



(MUM\<i;y needs from some simple compouiHls 

 prescMit in the ntmosphei'e. Heijerinck Mnd 

 \;ui neldeii tound tli;it the tolhiwinjj; ele- 

 ments are essential : X, P, K, and Mi;-. WIhmi 

 a simple syntlu^tie medium to which no cai- 

 l)on compounds had hccn added was inocai- 

 latiHJ with a small (luantity of soil and in- 

 cubated at 2.'{ to '2P)°i\ there ai)peafed "a 

 thin, white or t'lH'hly rose-colored, \'erv dry 

 (ilm, dillicult to moisten." Tlu> i>;rowth of the 

 lilm continued for months and resulted in 

 tlu> accunudation of considci'ahle amounts 

 of orj^anic mat(M-ial. [either nitrate oi' am- 

 monium salt could he us(>d as a soui'ce of 

 nitrojien. The carbon was derixcd fi'om \-ol- 

 atile carbon comi)ounds of the atmos])here. 

 Lantzsch, who identified this organism as an 

 actinomycete, differentiated between the 

 nutrition of two \-ariants, one a filamentous 

 form which assimilated CO; the other, a 

 coccus-like or bacillary form, which assim- 

 ilated aliphatic hydrocarbons. The organism 

 was considered to be an air purifier (Kober). 



With the growing recognition of the im- 

 portance of actinomycetes as producers of 

 antibiotics and vitamins, extensive studies 

 have been made of their metabolic processes. 



Waksman, Schatz, and Reilly (1946) 

 found that the growth of S. griseus reaches 

 a maximum in stationary cultures in 10 

 days and in submerged cultures in 3 to 5 

 days, followed by the lysis of the mycelium. 

 Growth of the organism is accompanied by 

 a gradual rise in the pH value of the culture 

 and hi the ammonia and amino nitrogen 

 contents. The total nitrogen in the myce- 

 lium tends to be higher during the active 

 stages of growth. The prc^duction and ac- 

 cumulation of streptomycin parallels the 

 growth of the organism (Table 18). After 

 maximum activity has been reached, there 

 is a rapid drop, especially in submerged cul- 

 tures. The production of streptomycin re- 

 ([uires the presence in the medium of a 

 complex organic substance, which either 

 .serves as the precursor of the streptomycin 



TIME. DAYS 



FujiRE 54. Mot;il)()lisiii of S. coelicolor (Repro- 

 (liU'od from: C'nchraiic, \'. W. and Dimmifk, I. 

 J. li.M-tciioi. .-)«: 727, l!)4i)). 



Table 18 



Rale of growth and streptomycin production of S. 



griseus in stationary cultures (Waksman, 



Schatz, and Reilly) 



Per 250-ml portion of medium. 



Incubation, Growth, 

 days gm 



Nitrogen Strepto- NH3-N NHi-N 

 in myce- mycin, in broth, in broth, 

 lium, mg Mg/ml mg mg 



molecule as a whole or of an important group 

 in the molecule, or functions as a prosthetic 

 group in the mechanism essential for the 

 synthesis of the antibiotic. This substance 

 was designated as "activity factor"; it can be 

 gradually sj'nthesized by the organism. 

 When it is provided in the medium in a pre- 

 formed state, however, as in meat extract or 

 in corn steep, the process of antibiotic syn- 

 thesis is greatly facilitated. 



In a study of the metabolism of S. aureo- 

 faciens in complex media containing .sucrose 

 and i)roteins, Biffi ct al. found that myce- 

 lium synthesis is rapid tluring the first 24 

 hours then slows down in the next 24 hours. 

 During the first 12 hours, sugar consump- 

 tion is negligible, while the XH3 content of 



