Light-Induced Proton Gradient Formation in Intact Cells of Dunaliella salina
AUTOR(ES)
Kaplan, Aaron
RESUMO
A light-induced proton gradient (ΔpH) increase as exhibited by an increase of 9-aminoacridine fluorescence quenching is demonstrated between the external medium and the interior of the halophytic green alga Dunaliella salina. The formation and maintenance of the ΔpH is sensitive to electron transport inhibitors and to uncouplers. It is inhibited by p-chloromercuribenzenesulfonic acid (50% inhibition at 3 micromolar), which does not affect photosynthetic O2 evolution. It is concluded that the observed ΔpH is located across the plasmalemma or the chloroplast envelope. The formation and maintenance of the light-induced proton gradient requires the presence of Na+. Substitution of NaCl by KCl or glycerol results in inhibition of the ΔpH formation. The proton gradient is also sensitive to ATPase and energy transfer inhibitors. It is suggested that a Na+/H+ pump mechanism may be involved in the formation of the proton gradient in intact Dunaliella cells.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=425920Documentos Relacionados
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