

RNA without H NO- 



RN A ♦ HN0 2 



TIME (MIN.) W 



20 30 40 SO 60 70 «0 



TIME ( HOURS ) 10 20 30 40 50 60 70 SO 



1.5 • 



URlDYLlC ACID 



05 



TIME (HOURS) 10 20 30 40 50 60 70 SO 



Fig. 8. Inactivation of TMV-RNA with HN0 2 at pH 4.3. (A) Loss in infectivity 

 (tested on Nicotiana glutinosa). (B) and (C) Chemical alteration of the RNA nu- 

 cleotides under the same conditions as in (A). Sum of the purine and pyrimidine 

 bases = 4. [H. Schuster and G. Schramm, Z. Naturforsch. 13b, 697 (1958).] 



279 



