METHODS OF ISOLATION 



57 



TABLE 6. GROWTH OF ANTAGONISTIC ORGANISMS ON BACTERIAL WASHED 

 AGAR MEDIA AND LYSIS OF BACTERIA 



ANTAGONISTIC 

 ORGANISM 



Bacteria: 

 B. brevis 

 B. simflex 

 Ps. aeruginosa 



Actinomycetes: 

 5. antibioticus 

 S. griseus 

 S, lavendulae 

 Micromonosfora sp. 

 N. gardneri 



Fungi: 



A. clavatus 

 A. flavus 

 A. fumigatus 

 Glioclaiium sp. 

 P. notatum 



MEDIUM CONTAINING WASHED CELLS OF 



E. coli S. lutea B. subtilis 



Growth Lysis Growth Lysis Growth Lysis 



O O 



o o 



O O 



O O 



O o 



O O 



O O 



O O 



h+ o 



H- O 



h+ O 



h+ o 



H- O 



From Waksman and Schatz (969). 



Note, o indicates no growtii of antagonist or lysis of test bacterium as shown by formation of 



clear zone on plate; ± indicates trace; + to I I I I indicates increasing amounts of growth or lysis. 



Direct Soil Inoculation Method 



Nutrient agar plates are inoculated with the bacteria or fungi for 

 which antagonists are to be found, and the plates are incubated for 24 

 to 48 hours at 28° or 37° C. Particles of fresh or enriched soil placed 

 on the surface of the bacterial or fungus growth on the plate will give 

 rise to antagonistic organisms that will bring about the killing or even 

 the lysis of the original culture. By this method, organisms antagonistic 

 to many bacteria and fungi causing plant and animal diseases have been 

 isolated (683,685). 



For the isolation of bacteria antagonistic to fungi, the latter are 

 grown on potato agars until they have spread over the plate j particles 

 of moist soil are then placed on the surface of the mycelium, and the 

 plates are incubated in a moist chamber. Bacteria lysogenic to the fungi 



