I EFFECTS OF RADIATION AND PEROXIDES ON 

 VIRAL AND BACTERIAL FUNCTIONS LINKED TO 



DNA SPECIFICITY 



Raymond Latarjet 



Laboratoire Pasteur du VInstitut du Radium, Paris 



In the course of the last few years, attention has been drawn 

 to the production of organic peroxides within irradiated 

 Hving cells, tissues, and organisms. These substances are in 

 general very reactive, and, in the presence of oxygen, they can 

 elicit chain reactions of peroxidation. It has been thought 

 that they might play the role of intermediates in the produc- 

 tion of certain radiolesions, i.e., the role of true radiomimetics, 

 profoundly affecting cell metabolism. As a matter of fact, 

 peroxides have already been considered responsible for the 

 posteffect of radiation, and for the sensitizing influence of 

 oxygen ; mutagenic and lethal effects have been obtained with 

 these substances; conversely, certain radiolesions have been 

 prevented by posttreatment with peroxidases. 



These considerations led me some time ago to undertake 

 quantitative experimental comparisons of some effects pro- 

 duced by organic peroxides and by radiation in simple biological 

 systems such as a bacterial transforming agent, bacteriophages 

 and bacteria, with special emphasis on some specific hereditary 

 characters carried by their DNA. The present paper groups 

 the first results obtained by my collaborators and myself. 

 It should be clearly understood; 



(a) that these results are of preliminary character; 



(b) that differences among biological systems and even 

 among peroxides forbid any generalization on these 

 results at the present time; 



(c) that, in our opinion, peroxides are only some examples 

 (perhaps very important ones) among the many chemical 

 mediators which are brought into play in irradiated 

 living systems. 



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