238 



PHYSIOLOGY OF THE FUNGI 



containing the vinylene group may be cited. Dittmer et al. (1948) found 

 methallylglycine, allylglycine, and crotylglycine to inhibit the growth of 

 Saccharomyces cerevisiae and Escherichia coli. The effects of these three 

 antimetabohtes on the growth of yeast are shown in Fig. 49. 



50 100 150 200 250 300 



Micrograms of unsoturoted amino acids per 7.5 ml. 



Fig. 49. The inhibition of growth of Saccharomyces cerevisiae, strain 139, by DL-allyl- 

 glycine, DL-methallylglycine, and DL-crotylglycine. (Courtesy of Dittmer, Goering, 

 Goodman, and Cristol, Jour. Am. Chem. Soc. 70: 2501, 1948. Published by permis- 

 sion of the American Chemical Society.) 



Natural amino acids. Antagonism among the amino acids is not 

 limited to competitive inhibition between naturally occurring amino 

 acids and their analogues. Robbins and McVeigh (1946) found hydroxy- 

 proline to inhibit the growth of several dermatophytes: Tricho-phyton 

 mentagrophytes, T. gypseum (granular form), T. purpureum, Epidermo- 

 phyton fiocculosum, and Microsporum canis. This inhibition was over- 

 come by proline. The relationship of these two naturally occurring 

 amino acids is shown below: 



H2C- 

 H.C 



-CH2 

 CH— COOH 



HOHC- 



H2C 



-CHo 



in- 



COOH 



N 



H 

 Proline 



N 



H 

 Hyd ro xy proline 



Low concentrations of hydroxyproline stimulated growth of Tricho- 

 phyton purpureum, while higher concentrations inhibited growth. Addi- 

 tion of hydroxyproline to a glucose-asparagine medium increased the 

 growth of Polyporus squamosiis. Hydroxyproline was without effect 

 on the growth of 19 other species of fungi. Whether amino-acid antago- 

 nisms may limit the nitrogen utilization of natural mixtures of these 



