THE EXPERIMENTS OF THE CHICAGO GROUP 



1651 



Clendenning (1950) made a closer study of the composition of the ben- 

 zene-soluble fraction A. After 20-sec. exposure, C* was found to be present 

 in tliis fraction in water-insoluble, nonvolatile compounds. The chloro- 

 phylls (a and h) were not tagged, and could be isolated free of C* by puri- 

 fication on sugar columns. After saponification of the A fraction, C* was 



10 SEC. LIGHT 

 6 SEC DARK 



pretreatment: ismin. illumination 

 in absence of cog , phosphate 

 buffer, ph 6.2 



TIMES: CONTACT WITH 



14 



c o. 



72.6% 



60 SEC DARK 



10 SEC LIGHT 



69.6% 



99% 



62.1! 



^■•^ 



ABC 



Fig. 36.11. C(14) fixation by Scenedesmus after 15 min. preillumination in the 

 absence of CO2 and O2. Light-shaded areas, phosphoglyceric acid; dark-shaded 

 areas, pyruvic acid; unshaded areas, other tagged compounds (after Gaffron et 

 al. 1951). 



found in the nonsaponified part, in fatty acids (saturated as well as un- 

 saturated), and in water-soluble products of saponification. 



These experiments showed that some C* enters lipoid products already 

 in the first minute of exposure to C*02. 



In revision of their earlier results, Fager, Rosenberg and Gaffron (1950) 



