144 FUNGI AS ANTAGONISTS 



eluting the active substance with ether, Wiesner (1012) obtained a 

 preparation having a bactericidal potency in dilutions of i : 100,000. 

 This activity was not inhibited by serum, pus, or urine j strains of bac- 

 teria that proved to be resistant to sulfonamides or mandelic acid were 

 inhibited by this material. 



The active substance was designated (957) clavacin. It is active 

 against E. colt and other gram-negative bacteria, as well as against 

 gram-positive bacteria. It is different in this respect from fumigacin. 

 Whereas the latter acts much more readily upon B. mycoides than B. 

 subiilis, clavacin shows the opposite effect — greater activity against B. 

 subtilis than against B. mycoides. Clavacin possesses a high bactericidal 

 action, as compared with other antibiotic substances. 



A detailed study of its production by a variety of strains of A. clava- 

 tus was made (968). The marked differences in the physiology of the 

 different strains of A . clavatus were said to explain the differences in the 

 production of clavacin by different strains. Those that change the re- 

 action of the medium to alkaline, for instance, tend to inactivate the 

 clavacin. 



Since clavacin is produced by a number of different fungi, it has re- 

 ceived a number of designations, including patulin formed by P. fatu- 

 lum (744), claviformin by P. claviforme (124, 125), and clavatin 

 (47). It is also produced by strains of P. exfansum-y P. urticaey A. ter- 

 reuSyA. giganteusy GymnoascuSy and others (24, 486, 501). For species 

 of Penlcilliufn it was found (578) that glucose as a source of carbon, an 

 incubation temperature of 20° C, stationary culture, and a source of 

 iron offer optimum conditions. 



Trichoderma and Gliocladmm Grouf 



Certain strains of fungi of the genera Trichoderma and Gliocladium 

 were found to exert a marked antagonistic action against various fungi 

 and bacteria. An antibiotic substance designated as gliotoxin was iso- 

 lated and found (82, 989) to be highly bactericidal. In order to produce 

 this substance, the fungus is grown in a submerged condition in shake- 

 cultures. An abundant supply of oxygen and a high acidity (/)H 5.0 or 

 lower) are essential. Ammonium salts as nitrogen sources give better 

 results than peptone or nitrates. Glucose and sucrose were found to be 



