CHAPTER 7 



FUNGI AS ANTAGONISTS 



The antagonistic interrelationships in which fungi are involved com- 

 prise the following reactions: (a) the antibacterial activities of fungi j 

 (b) the antagonistic effects of fungi upon fungi; (c) the effects of bac- 

 teria and actinomycetes upon fungi; (d) the action of fungi upon in- 

 sects and other animal forms. From the point of view of practical utiliza- 

 tion, two aspects deserve special consideration: (a) the utilization of 

 fungi for combating human and animal diseases; (b) the antagonistic 

 interrelationships of fungi with o'ther organisms, since fungi comprise 

 the most important group of microorganisms that cause plant diseases. 



ANTIBACTERIAL EFFECTS OF FUNGI 



Apparently Gosio is to be credited (268) with having first demon- 

 strated that a crystalline material produced by a species of Penkillium 

 has the capacity of inhibiting the growth of a bacterium, namely B. an- 

 thracis; this substance is now known as mycophenolic acid. Soon after- 

 ward, in 1897, Duchesne (211) reported that certain green Penicillia 

 are capable of repressing the growth of various bacteria or of bringing 

 about their attenuation. Vaudremer (934) demonstrated in 19 13 that 

 the presence of A. jumigatus results in the attenuation of the cells of 

 M. tuberculosis. 



Vaudremer (934) was the first to attempt the clinical utilization of 

 a fungus product. He treated "more than 200 patients" suffering from 

 tuberculosis with extracts of the fungus; although no toxic effects were 

 observed, the curative properties of the preparation were such as not to 

 justify any significant conclusions. 



Since these early studies a number of fungi have been found to pos- 

 sess antibacterial properties; this phenomenon has sometimes been 

 spoken of as mycophagy (935a). Several fungi have been studied in de- 

 tail, and in some cases one or more antibiotic substances have been iso- 

 lated (Figure 12). The property of inhibiting the growth of bacteria is 



