REFERENCES 293 



We mentioned in the introduction that radiation death in organisms 

 could be effected by many factors. Hydrogen peroxide may be one of 

 the contributing factors, but other radicals found in the decomposition 

 of water by radiation may play a special role in contributing to the 

 killing of the organisms. The effect of oxygen in regard to the sensi- 

 tivity could be largely explained by such a hypothesis. I feel that we 

 are basing our speculation too much on studies which have been con- 

 ducted with pure water, whereas in living cells, where really "pure" 

 water does not exist, there must be a loose association of molecules 

 which could be affected by these radiation-produced radicals. A typical 

 example would be a nucleoprotein built into chromatin material. It 

 appears somewhat promising that untangling metabolism mechanisms 

 effected by oxygen under the influence of radiation will give us a clue 

 to this problem. Finally, the inactivation of the sulfhydryl-requiring 

 enzyme systems discussed by Barron may also play an important role. 



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