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BARRON: This was 99. 5 percent peroxide obtained from Niagara 

 Falls. 



HOLLAENDER: Most of the commercial peroxide has a stablizing 

 substance incorporated in the suspension. 



BARRON: No, this is pure peroxide. 



ALLEN: It is supposed to be inhibitor-free. 



TOBIAS: Are these effects identical with X rays? 



CARTER: They have used peroxide plus UV and very extensive degra- 

 dation is produced. Whether it is identical, I don't know. 



KAMEN: Radiation has the same effect. 



CARTER: Yes, it does but is it identical? 



KAMEN: It is identical with low radiation doses. With high radiation 

 doses it is different. 



CARTER: Well, the point that I want to bring out from this discussion 

 is that apparently peroxide radicals are formed on the nucleic acid which ac- 

 tually participate synergistically in this phenomenon. 



POLLARD: Has anybody ever tried dry nucleic acid? 



CARTER: Yes, it has been done. 



POLLARD: What happens? 



HOLLAENDER: You have to go much higher. 



CARTER: I think, too, that we must include the factor of protein in 

 the high molecular weight structure. I don't know of any evidence which would 

 indicate that nucleic acids exist as free nucleic acids. They are polyelectro- 

 lytes, and undoubtedly they exist in combination with protein. Is that all right 

 with you, Dr. Chargaff? 



CHARGAFF: Sure. 



CARTER: So that actually when we study effects of radiation upon 

 these high molecular weight compounds, the studies should be conducted on a 

 nucleoprotein if we want data applicable to cell biology. This problem has been 

 studied by Anderson in Hollaender's laboratory and he finds that there is much 

 greater sensitivity as measured in terms of viscosity drop when a nucleoprotein 

 is irradiated compared with a nucleic acid. I believe this is because the factors 

 of high molecular weight orientation are probably preserved more closely to the 

 native state in these nucleoproteins, and that actually you have an increased 

 degree of sensitivity in your measurements simply because of high molecular 

 weight orientation. 



There may be another interpretation. Nevertheless, there is now 



dequate evidence that doses as low as 25 r will produce extensive depolymeri 

 ation or at least extensive changes in terms of viscosity alteration in the mol 



