ACTIVATORS AND INHIBITORS OF GERMINATION 



61 



Table VIII 



Inhibition of L-amino acid activation by 



D-amino acids. Suspension 5230-5 



Substance Added 



2-3 



Mean Spore Count per Plate 

 Incubation Time in Days 

 5-6 9-10 15-17 20-23 



5504 



L-serine 



DL-serine 



L-valine 



DL-valine 



L-alanine 



DL-alanine 



5230-5 and 5230-24. As strong activators we find only L-alanine, /3-alanine 

 and L-valine. The inactive substances include DL-methionine, DL-phenyl- 

 alanine, L-phenylalanine, L-glutamic acid, DL-serine, L-threonine, furfural 

 and Mn+ + . Some substances are listed as weak with a long lag. Further con- 

 sideration of the data of these experiments suggests that L-arginine, L-Ieu- 

 cine, NH4CI and Na pyruvate should be transferred to the inactive column, 

 leaving only L-methionine and L-serine in the group showing weak but def- 

 inite activation. 



Table VIII shows the inhibition of L-amino acid activation by D-amino 

 acids. As noted before, the inhibition of L-alanine by D-alanine and 

 L-valine by D-valine is overcome by prolonged incubation. The inhibition 

 of L-serine by D-serine appears to be of a more extended nature. In fact. 



