Health & Environmental Research Online (HERO)


Print Feedback Export to File
8687612 
Journal Article 
Intracellular sodium and potassium concentrations and net cation movements in Chlorella pyrenoidosa 
Shieh, YJ; Barber, J 
1971 
1 
Biochimica et Biophysica Acta. Biomembranes
ISSN: 0005-2736
EISSN: 1879-2642 
223 
3 
594-603 
English 
1. 1. Chlorella cells will accumulate K+ to a high internal level if this cation is present in the bathing medium. 2. 2. In the absence of external K+ these cells will accumulate Na+. 3. 3. When K+ was added to a suspension of these Na+-rich cells a relatively rapid exchange of internal Na+ for external K+ occurred with a half time of less than 10 min. 4. 4. During this change of internal Na+ for K+ there was no obvious change in the rates of respiration or photosynthesis. 5. 5. The Na+K+ exchange was sensitive to light and temperature and seemed to be under metabolic control. 6. 6. Inhibition of the net fluxes with carbonyl cyanide m-chlorophenylhydrazone and N,N′-dicyclohexylcarbodiimide implicates phosphorylation and a membrane-bound ATPase with the exchange. 7. 7. The action of 3-(3,4-dichlorophenyl)-1,1-dimethylurea and anaerobic conditions on illuminated cells suggested that the Na+K+ exchange can be supported by cyclic phosphorylation. 8. 8. The Na+K+ exchange was not inhibited by the cardiac glycoside, ouabain. 9. 9. In addition to the Na+K+ exchange there also seemed to be a H+K+ exchange which represented about 10% of the total net cation movement. 1971.