OXIDATIVE KNZYMKS OF HACTKKIAL SI'OKK KXTRACTS 161 



oxidations, but obtained results which were difilcult to interpret ( Powell, 

 J. F. unpublished results. Resting spores of these organisms tested intact 

 and mechanically disintegrated catalyzed the oxidation of p-phenylene dia- 

 mine (Qo^, 37° =^ 60 ( and hydnxjuinone (Qo., 25° ^ 30). There was, how- 

 ever, no stimulation of this oxidation by added cytochrome C. The oxida- 

 tion catalyst of B. subtilis was unaffected by heating at 60° for 15 min., 

 whereas that of B. megatherium was 75% destroyed. Spores of B. subtilis 

 showed no change in oxidative activity after germination in L-alanine solu- 

 tion and the catalyst remained heat stable. Spores of B. subtilis catalyzed 

 the oxidation of ascorbic acid and of reduced cytochrome C. Disintegrated 

 spores were rather more active than spore extracts in the oxidation of re- 

 duced cytochrome C. On a dry weight basis, disintegrated vegetative cells 

 appeared to be roughly ten times as active as disintegrated spores. 



These results, though rather scattered and incomplete, suggest that spores 

 contain a DPN-linked flavoprotein system and possibly a cytochrome sys- 

 tem of relatively low activity compared with that of vegetative cells. The 

 germination of spores of B. subtilis and B. megatherium was not inhibited 

 by cyanide or azide (Powell. J. F.. unpublished results; Powell, J. F., 1951 1 

 and the rate of glucose oxidation by these germinated spores was consider- 

 ably less sensitive to cyanide than that of the corresponding vegetative cells 

 (Spencer and Powell, 1951). It therefore appears that the constitution of 

 the cytochrome system and its function change during sporulation and re- 

 vert during the development of the germinated spore into a growing vege- 

 tative cell. Such changes in cytochrome constitution during the sporulation 

 cycle might be very profitably studied using the spectrophotometric tech- 

 niques developed by Chance ( 1952 1 and already applied to bacteria by 

 Smith (1954). 



It appears that these changes in the terminal oxidation systems may be 

 paralleled by changes in the pathway of glucose oxidation. Dr. Halvorson 

 has pointed out that vegetative cells of Bacillus species possess glycolytic 

 activity as well as components of the phosphorylitic shunt which appear to 

 be absent from resting spores. These systems must therefore fade out at 

 sporulation and re-appear as the spore germinates and grows. 



It is interesting to speculate on the connection between these changes in 

 ezymic activity of the cell and the initiation of the sporulation process. 

 Cantino (1956) in his studies on the sporulation of the water mold Blasto- 

 cladiella has shown that the weakly-functional tricarboxylic acid cycle in 

 this organism disappears at sporulation and reappears at the start of the 

 next generation. The initiation of sporulation and the accumulation of in- 

 termediates in the tricarboxylic acid cycle could be induced by the addition 

 of bicarbonate to the growth medium. It seems likely that similar studies with 



