DEAN' B. COWIK AND RICHARD B. ROHKRTS 



27 



Measurement of the radioactivity of the wash solutions gave a water space 

 of 66 and 63% for the two pellets of cells. Chromatograms of the immersion 

 fluid before the addition of the cells were compared with chromatograms of 

 the first wash solution. The distribution of radioactivity was the same. Identi- 

 fication of the reduced and oxidized peptide was possible from radioautographs 

 of the paper chromatograms and their ninhydrin 'lingerprints' on the paper 

 chromatograms. 



These results demonstrate that penetration by passive diffusion occurs. 

 This penetration must be rapid since the sulfur of glutathione can compete 

 for utilization with sulfate sulfur (24). The appearance of glutathione in the 

 culture fluid of growing cells demonstrates the outward passage of glutathione. 



Table 21. Immediate uptake of 

 glutathione by e. coli 



Table 22. Immediate uptake of 

 c"-fructose 



* Peptide concentration per ml immer- 

 sion fluid, I mg. 



t Wash solution volumes, 5 ml. 



The water space measured for E. coli with these oxidized and reduced peptides 

 is approximately equal to that obtained for inorganic ions and amino acids. 

 Permeability of Escherichia Coli to Fructose. Fructose is able to diffuse 

 passively into and out of the E. coli cell as shown in table 22. E. coll cells, 

 grown overnight in a synthetic medium containing glucose, were harvested 

 and washed in 0.85% saline solution. A fraction of these cells (0.61 grams w^et 

 weight) w^ere resuspended in fresh synthetic medium containing 200 mg C'- 

 fructose per ml medium. The cells and medium were maintained at t,°C for 

 15 minutes and then centrifuged. The chilled pellet of cells was then immersed 

 in 2 ml of 3°C synthetic medium containing C'^ fructose at the above concen- 

 tration. There was little metabolic incorporation of the labeled fructose as 

 shown in table 22 and, by supernatant analysis, the water space measurement 

 was 78%. The C^^ fructose was prepared from canna leaves (22, 28) using 

 BaCi^Oa as a source of COa. 



