214 CHEMICAL NATURE OF ANTIBIOTIC SUBSTANCES 



fungi, especially those pathogenic to man and to plants. This effect is 

 largely fungistatic, giving titers up to i :8o,000 (271). 



Glutinosin is produced by Metarrhizimn glutinosum grown on syn- 

 thetic media (83a). The substance is extracted with ether, n-h\i.ty\ alco- 

 hol, or petroleum ether. The solvent is evaporated and the material 

 crystallized from ethyl alcohol in the form of thin, colorless plates, free 

 from S and N. It does not melt at 300° C. It has specific antifungal ac- 

 tivity, inhibiting spore germination, but does not possess any antibac- 

 terial properties. 



SUBSTANCES PRODUCED BY YEASTS 



According to Fernbach (252), certain yeasts produce volatile sub- 

 stances which are toxic not only to other yeasts but also to bacteria. Rose 

 yeasts {Torula suganii), either fresh or heated to 120 to 130° C, were 

 found (690) to contain a substance which has an antagonistic action 

 against fungi, especially in the young mycelial stage, but not against 

 yeasts ; the growth of A . niger was reduced by 60 to 70 per cent and 

 that of A. oryzae by 25 to 30 per cent. The substance was not found in 

 the ash of the organism and was not secreted in the filtrate, but re- 

 mained in the yeast cells. An alkaline reaction was unfavorable to its 

 formation and action. The active substance was soluble in acetone, alco- 

 hol, ether, and chloroform, and was adsorbed by kaolin, Seitz filter, 

 paper, and by the fungus mycelium. It could be removed from the 

 kaolin by treatment with ether or acetone. Acetone-treated yeast no 

 longer had an antagonistic effect, but only a stimulating one. 



According to Schiller (835), yeasts produce a bacteriolytic substance 

 only in a state of "forced antagonism," that is, in the presence of staphy- 

 lococci and certain other bacteria. The substance is thermolabile, since 

 it is destroyed at 60° C. It is active also outside the cell. More recently 

 ( 151 ), the active substance of yeast was concentrated. In a crude state, 

 the active material was found to be nonvolatile and readily soluble in 

 water, in 95 per cent alcohol, and in acetone containing a trace of water. 

 It was stable at 100° C. at fH 7.3. It contained nitrogen but no sulfur. 

 Although a positive biuret reaction was obtained, it appeared that the 

 protein was present as an impurity. 



