118 ACTINOMYCETES AS ANTAGONISTS 



used as the test organism. On this basis, 87 cultures (53.1 per cent) 

 were found to be inactive, 53 cultures (32.3 per cent) were moderately 

 active, and 24 cultures (14.6 per cent) were highly active. The conclu- 

 sion was reached (1000) that bacteriolytic activities against killed bac- 

 teria and living gram-positive bacteria are widely distributed among 

 the actinomycetes. Growth-inhibiting properties of actinomycetes were 

 found to be significantly associated with bacteriolytic action upon living 

 gram-positive bacteria. 



Certain actinomycetes also show antagonistic activities against fungi 

 (10-12, 908). S. albus was capable of inhibiting the growth of all the 

 species of fungi tested, an effect shown to be due to the production 

 of an active substance. By the use of a culture of Colletotrkhum gloe- 

 osforioideSj the antagonistic activities of 80 type cultures of actino- 

 mycetes were measured. The antagonist was allowed to grow for 5 days 

 on maltose agar, at fH 7.4, and the fungus was then inoculated. The 

 cultures of actinomycetes were divided, on this basis, into three groups: 

 strong, weak, and noninhibitors. The first group comprised 17.5 per 

 cent of the cultures j the second, 38.8 per centj and the third, 43.7 per 

 cent. These results are surprisingly similar to those reported for the 

 distribution of actinomycetes possessing antibacterial properties, includ- 

 ing those that were isolated at random from the soil and those taken 

 from a culture collection. 



Meredith (633) made a survey of the distribution of organisms an- 

 tagonistic to Fusarium oxys forum cubense in Jamaica soils j most of 

 these antagonists belong to the actinomycetes. The antagonists were not 

 evenly distributed in the various soil samples, 10 of the d^i samples giv- 

 ing 44 per cent of the antagonistic organisms. Those actinomycetes that 

 were antagonistic to Fusarium when grown in their own soil-solution 

 agar were not always antagonistic when tested in soil-solution agar pre- 

 pared from other soil. A culture of actinomyces isolated from a compost 

 produced lysis of the Fusarium. When spores of both organisms were 

 mixed in an agar medium, the fungus developed normally for two days 

 but began to undergo lysis on the fifth day, large sections of the my- 

 celium disappearing. On the seventh day only chlamydospores were ob- 

 served. In 9 days the fungus completely disappeared, the actinomyces 

 making a normal growth. 



