Production of Antibiotic Substances 



279 



In view of the fact that the organisms producing antibiotics are 

 of soil origin, the question has naturally been raised of what im- 

 portance those substances are in soil processes. It has been estab- 

 lished, for example, that various bacteria, both beneficial and harm- 



FiG. 111. Electron micrograph of actinophage, type I, of streptomycin-producing 

 Streptomtjces griseus X31,000 (courtesy of Squibb Institute for Medical Re- 

 search ) . 



ful, are affected by certain antibiotics; the former include the root- 

 nodule bacteria and Azotohacter, and the latter include bacteria 

 causing various blights and other plant infections. 



The effect of antibiotics upon the soil microbiological population 

 has given rise to various speculations. 



On the one hand, certain claims have been put forth that this 

 phenomenon is of only minor importance in soil processes. The 

 following reasons have been presented to substantiate this view: 



