S. SPIEGELMAN AND A. M. CAMPBELL 



soning assumes, of course, that the four bases are the only com- 

 ponents of the code. 



An alternative explanation of these findings can be offered. 

 It may be that the active fragments of Gale-Folkes may, by 

 transfer reactions, generate the nucleotide components func- 

 tioning in the activating mechanism suggested by the work of 

 Hoagland (37) and DeMoss and Novelli (22). Whatever the 

 interpretation, it nevertheless remains true that these results 

 are pregnant with many possibilities. 



As distinguished from incorporation studies, the attainment 

 of protein synthesis has been reported in only two sorts of sub- 

 cellular fractions. One is the system of Gale and Folkes (28) in 

 which the development of "glucozymase," catalase, and the in- 

 ductive formation of beta-galactosidase have been demon- 

 strated. When these preparations are sufficiently resolved 

 either by removal of RNA or DNA, it is found that both DNA 

 and RNA stimulate the formation of both catalase and beta- 

 galactosidase. 



Again, the relative high activity of the DNA may be a con- 

 sequence of greater stability to extractive procedures. No 

 limits to the potentialities of this system are apparent. It is 

 difficult to believe that its further study can fail to provide defin- 

 itive answers to the basic problems of template function and 

 specificity. 



Another system which gives great promise of future fruit- 

 fulness are the so-called "protoplasts" of B. megaterium. Wei- 

 bull (100) showed that these could be prepared by treatment of 

 cells with lysozyme in hypertonic medium. Wiame et al. (101) 

 showed that these preparations were able to synthesize arabino- 

 kinase as demonstrated by an increased Qoj during incubation. 

 Simultaneously Landman and Spiegelman (44) isolated a lac- 

 tose positive mutant of B. megaterium and devised a stabilizing 

 medium for protoplasts which permits synthesis of beta-galac- 

 tosidase. Virtually all of the enzyme-forming capacity is re- 

 covered in the protoplasts. When supplemented with amino 

 acids, hexose-diphosphate, and inducer, they synthesize enzyme 



156 



