Photodynamic effects of hypericin on photosynthetic electron transport and fluorescence of Anacystis nidulans (Synechococcus 6301)

1996 ◽  
Vol 48 (1-2) ◽  
pp. 221-226 ◽  
Author(s):  
George C. Papageorgiou ◽  
Aikaterini Alygizaki-Zorba ◽  
Spyros Loukas ◽  
Steven S. Brody
Keyword(s):  
Electron Transport ◽  
Photosynthetic Electron Transport ◽  
Anacystis Nidulans ◽  
Synechococcus 6301

scholarly journals Modification of a gInB-like gene product by photosynthetic electron transport in the cyanobacterium Synechococcus 6301

FEBS Letters ◽  
1990 ◽  
Vol 264 (1) ◽  
pp. 25-28 ◽  
Author(s):  
Michael A. Harrison ◽  
Jeffrey N. Keen ◽  
John B.C. Findlay ◽  
John F. Allen
Keyword(s):  
Electron Transport ◽  
Gene Product ◽  
Photosynthetic Electron Transport ◽  
Synechococcus 6301

Superoxide-and Ethane-Formation in Subchloroplast Particles: Catalysis by Pyridinium Derivatives

1980 ◽  
Vol 35 (9-10) ◽  
pp. 770-775 ◽  
Author(s):  
E. F. Elstner ◽  
H. P. Fischer ◽  
W. Osswald ◽  
G. Kwiatkowski
Keyword(s):  
Electron Transport ◽  
Photosystem I ◽  
Photosynthetic Electron Transport ◽  
Redox Potentials ◽  
Light Reaction ◽  
Pyridinium Bromide ◽  
Superoxide Formation ◽  
Fatty Acid Peroxidation ◽  
Chlorophyll Bleaching ◽  
Ethane Formation

Abstract Oxygen reduction by chloroplast lamellae is catalyzed by low potential redox dyes with E′0 values between -0 .3 8 V and -0 .6 V. Compounds of E′0 values of -0 .6 7 V and lower are inactive. In subchloroplast particles with an active photosystem I but devoid of photosynthetic electron transport between the two photosystems, the active redox compounds enhance chlorophyll bleaching, superoxide formation and ethane production independent on exogenous substrates or electron donors. The activities of these compounds decrease with decreasing redox potential, with one exception: 1-methyl-4,4′-bipyridini urn bromide with an E′0 value of lower -1 V (and thus no electron acceptor of photosystem I in chloroplast lamellae with intact electron transport) stimulates light dependent superoxide formation and unsaturated fatty acid peroxidation in sub­ chloroplast particles, maximal rates appearing after almost complete chlorophyll bleaching. Since this activity is not visible with compounds with redox potentials below -0 .6 V lacking the nitrogen atom at the 1-position of the pyridinium substituent, we assume that 1 -methyl-4,4′-bi-pyridinium bromide is “activated” by a yet unknown light reaction.

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