Plant Physiol. Tips for Better Browsing
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Plant Physiology 66:446-450 (1980)
© 1980 American Society of Plant Biologists

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Web of Science (39)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Spiller, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Spiller, H.
Agricola
Right arrow Articles by Spiller, H.
Articles

Photophosphorylation Capacity of Stable Spheroplast Preparations of Anabaena1

Hart Spiller2

Fakultät für Biologie Universität Konstanz, D-7750 Konstanz, West Germany

Spheroplasts from Anabaena 7119 (formerly designated Nostoc muscorum) were prepared in the presence of serum albumin in 0.5 molar sucrose. Electron transport and photophosphorylation were preserved (> 70% of the maximum rate for 1 week). The pH profile of electron transport and photophosphorylation in the reactions H2O -> NADP, H2O -> methyl viologen, and H2O -> ferricyanide shows that uncoupling by ammonia is small throughout and increases slightly with higher pH. ADP + Pi increased NADP reduction from H2O by 2.5-fold. The ratios of ATP formed per electron pair transported ranged from 0.9 to 1.5. Effects of catalase and superoxide dismutase on the overall O2 balance implicate pseudocyclic electron transport and phosphorylation. The quenching of 9-aminoacridine fluorescence indicates the formation of a {Delta} pH from 2 to 2.6 during illumination. This pH gradient is abolished by uncouplers; however, complete uncoupling is achieved only by 3-chlorocarbonyl cyanide phenylhydrazone or valinomycin + NH4+. In the presence of NH4+ alone, the membrane potential may act as the driving force for photophosphorylation.

Increasing amounts of bovine serum albumin protected phosphorylation from uncoupling by silicomolybdic acid. 3-(3,4-Dichlorophenyl)-1, 1-dimethylurea-insensitive water oxidation by silicomolybdic acid provides evidence that the site for 3-(3,4-dichlorophenyl)-1, 1-dimethylurea action is on the acceptor and not donor side of photosystem II in the procaryote Anabaena. It is concluded that stable spheroplasts retain coupled electron transport approaching in vivo rates.

2 Present address: Plant Growth Laboratory, University of California, Davis, Calif. 96516.

1 This research was supported by the Deutsche Forschungsgemeinschaft through its Sonderforschungsbereich 138 at the University of Konstanz.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 1980 by the American Society of Plant Biologists