218 



THE ACTIXOMYCETES Vol. I 



Table 57 



Inhibitor!/ activity of streptoniyces against selected phytopathogemc 

 bacteria and fungi (Pridham et al., 1956) 



of a rather large number of specific anti- 

 biotic-producing strains. They found such 

 strains to be present in four of the five soils 

 tested. This would seem to indicate a wide 

 distribution of such organisms. 



In the process of screening thousands of 

 soil samples from widely scattered geograph- 

 ical areas, Routien and Finlay found or- 

 ganisms producing certain antibiotics to be 

 extremely common. Actinomycetes elaborat- 

 ing streptomycin, streptothricin, chloram- 

 phenicol, actinomycin, and xanthomycin- 

 likc antibiotics apparently have a world-wide 

 distribution. The tetracycline-producing cul- 

 tures have been isolated only a few times. 

 One antibiotic was observed from only one 

 culture isolated from one particular soil. 

 These investigators found that certain anti- 

 biotics are produced by (-ultures of actino- 

 mycetes common in soils from somewhat 

 localized areas. On the other hand, soils col- 

 lected within a restricted area were found to 

 yield a number of different antibiotics. 



Routien and Finlay emphasized that 

 variations in the degree of activity of dif- 

 ferent cultures are frequent. Some cultures 

 may decline in potency. Some cultures may 

 produce only small quantities of an anti- 

 biotic, which, on concentration, may be found 

 to possess new and useful properties. 



The wide distribution of antagonistic 

 properties among actinomycetes has thus 

 been definitely established. Members of the 

 genus Streptomyces are most active. They 

 occur abundantly in soil (Rouatt d al., 1951). 

 lilven the plant pathogenic S. scabies pos- 

 sesses antagonistic properties (Ark and 

 Oswald), although this organism, as well, is 

 subject to the antagonistic action of certain 

 fungi (Dailies, 1987). V'arious nocardias are 

 capable of exerting an antagonistic action, as 

 shown by Uesaka and by others. 



In summarizing the results of evaluation of 

 antibiotic activities of 10,000 streptomyces 

 cultures isolated from various substrates, 

 Woodruff and McDaniel stated that, on the 



