278 



ELECTRON TRANSPORT 



1.0- 



o 



(A 



o 



E 



E 



0.5- 



Q. 



3 



OQ.O 



0.0 



0.5 1.0 



ETHANOL (M) 



2.0 



Fig. 2. Effect of ethanol on oxygen consumption by light-grown cells of R. 

 nibnim. Experimental conditions were the same as for Fig. 1 except that 

 ethanol was added as indicated. 



respiration was never less than 1.7 (Fig, 3). This accords with the 

 well-known fact that ethylene glycol is an efficient solvent for storage 

 of photophosphorylating chromatophores below 0°C, In contrast, 

 respiration of the dark-grown cells was hardly influenced in the pres- 

 ence of 0.15 M /?-butanol. 



Carbon monoxide and cyanide, as typical respiratory inhibitors, 

 markedly inhibited respiration of either the dark-grown or the light- 

 grown cells. With the light-grown cells, dark and light respiration both 

 were inhibited by cyanide, but the ratio of dark-to-light respiration 



