Waksman 



— 110 — 



Actinomycetes 



teria. Under the influence of this bactericidal factor, the microbial cells 

 were either entirely lysed or were killed without subsequent lysis. The 

 action upon spore-forming bacteria was bacteriostatic rather than bacteri- 

 cidal (238). The antibiotic substance studied by these and other Rus- 

 sian workers was believed to be similar to lysozyme. 



An attempt to isolate an antibiotic substance from some of the soil 

 actinomycetes was made by Kriss (243). This substance was in- 

 soluble in ether, petroleum ether, benzol, and chloroform, and was re- 



FiG. 23 a.— The use of M. tnhercidosis for testing production of anti- 

 biotic substances by actinomycetes. Upper horizontal streak H37Rv 

 strain; lower streak fl37RvR (resistant to > 1000 Atg/ml streptomycin): 

 inhibition of streptomycin-sensitive but not of streptomycin-resistant 

 strain Qfrom Williston et al., 510). 



sistant to the eff^ects of hght, air, and high temperatures. The optimum 

 reaction for its production by Stre-ptoinyces vioJaceus was found to be 

 pH 7.1 to 7.8, the activity not being increased by selective cultivation. 

 Although it was believed that the substance is similar to egg-white 

 lysozyme, the above properties hardly justify this conclusion. The dif- 

 ferences in the antibiotic properties of the various antagonistic actino- 

 mycetes isolated by the Russian investigators definitely point to the fact 

 that more than one antibiotic substance was involved. 



