328 



A. N. BELOZERSKIÏ 



RNA by (G + C)/(A + T) DNA) may fully correlate by its composition with 

 that of DNA. On the other hand, one may think that the main mass of cellular 

 RNA does show no correlation with DNA, its composition being similar in very 

 different species. 



The pronounced specificity of DNA as compared with RNA is well illustrated 

 by the data obtained in our laboratory by A. S. Spirin in studying the DNA of 

 certain bacteria of the intestinal group in the process of their experimental 

 variability [2]. The following cultures were chosen for this investigation: (i) the 

 original cvilture of Escherichia coli 'CM'; experiments were conducted with this 

 culture in direction of artificially altering its properties by growing it together 

 with Bacterium enteriditis Breslau killed by heat; (2) Bact. enteriditis Breslau, 

 No. 70, whose killed bodies were used as a specific substrate to alter the pro- 

 perties 0Ï E. coli 'CM'; (3) alkaU-producing form 11-IV-4 obtained from E. coli 

 'CM' by growing it together with Breslau Bacteria No. 70 killed by heat, and 

 (4) paratyphoid-Uke strain, 12-IV-4 obtained by growing the alkali producer 

 11-IV-4 with Breslau Bacteria, N. 70 killed by heat [12, 13]. 



Tables 5 and 6 show the results of the study of the nucleotide composition 

 of DNA and RNA in the above-listed bacteria. 



Table 5 



DNA composition of investigated cultures 



Table 6 

 RNA composition of investigated cultures 



