Waksman 



— 112- 



Actinomycetes 



a whole, of certain groups of bacteria (249), of fungi pathogenic to man 

 (391), of viruses (196), and of phages (392, 393). 



The antagonistic properties of actinomycetes are not limited to mem- 

 bers of the genus Streptomyces. A culture of Nocardia, isolated by 

 Gardner (129) as an air contaminant, was found to produce antag- 

 onistic effects against a variety of gram-positive bacteria. The active 

 substance produced by this organism was designated as 'proactinomycin. 

 A representative of the genus Micromonospora was also reported (503) 

 to be capable of exerting antagonistic effects against certain bacteria. 



Actinomycetes also reveal antagonistic activities against fungi (424). 



Table 21 : Distribution of antagonistic actinomycetes in nature (468) :■ 



• I— Most 

 methods used. 



-more limited antagonistic properties; IV — no antibacterial effects 



Alexopoulos (8, 9) made a survey of the antagonistic properties of 

 80 cultures of actinomycetes, using Colletotrichum gloeosporioides as the 

 test organism. The following results were obtained: 17.5 per cent of 

 the cultures were strong inhibitors, 38.8 per cent were weak inhibitors, 

 and 43.7 per cent had no inhibiting effect upon the fungus. 



Meredith (291) surveyed the distribution of organisms antagonistic 

 to Fusarium oxysporum ciihense in Jamaica soils. Most of these an- 

 tagonists belonged to the actinomycetes. The antagonists were not 

 evenly distributed in the various soil samples, 10 of the 66 samples yield- 

 ing 44 per cent of the antagonistic organisms. Those actinomycetes 



