350 



[Vol.. 10 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



('14) are very significant; they found that the best source of N 

 for yeast is the autolysate of the yeast itself. Similarly Zaleski 

 and Pjukow ('14) showed that fungous autolysate was superior 

 to (NH«)iSO« as an N source for Aspergillus niger. 



It seems well to reconsider here the opinions of Ehrlich, Czapek, 

 Zaleski, and others on the form in which N is directly assimilated 

 from various N sources. While there is no conclusive proof that 

 N obtained by the fungi from amino acids, peptids, amines, 

 alkaloids, etc. is actually in the form of ammonia, the nicetv of 



S 



<Ntv,<S0r~ 



NhkNOs 



>t 



^ 



+£ 



3*5 





OAYS 



Fig. 10 



amount 



Aspergillus niger, third series. 



media 



the equations developed by Ehrlich and his associates, together 

 with quantitative proof in some cases, makes it seem likely that 

 the NH, and probably its simple substitution products are the 

 forms directly assimilated. More evidence for this is the fact 

 that Fischer obtained the diamino acids of 3 vinvl acrvlic acid. 





sorbic and fumaric acids by the direct action of ammonia on 

 these acids. It does not require a great stretch of the imagination 

 to think of the highly reactive cleavage products of sugars be- 

 having similarly toward NH,. This assuredly does not preclude 

 Czapek's theory of the direct utilization of amino acids and other 



