High-light-dependent upregulation of carotenoids and their antioxidative properties in the cyanobacterium Synechocystis PCC 6803

Light-dependent carotenoid formation has been investigated in the cyanobacterium Synechocystis PCC 6803. Upon transfer of cultures from low- (35 μmol m −2 s −1) to high-intensity illumination (500 μmol m −2 s −1), a decrease of the endogenous carotenoids to 85% of the initial value is observed. Trea...

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Bibliographic Details
Published in:Journal of photochemistry and photobiology. B, Biology Biology, 1999-10, Vol.52 (1), p.14-18
Main Authors: Steiger, Sabine, Schäfer, Lutz, Sandmann, Gerhard
Format: Article
Language:English
Subjects:
algal culture
Carotenoid protection
carotenoids
Cyanophyta
Echinenone
Light regulation
myxoxanthophyl
Myxoxanthophyll
Photo-oxidation
Synechocystis
Synechocystis PCC 6803
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Summary:Light-dependent carotenoid formation has been investigated in the cyanobacterium Synechocystis PCC 6803. Upon transfer of cultures from low- (35 μmol m −2 s −1) to high-intensity illumination (500 μmol m −2 s −1), a decrease of the endogenous carotenoids to 85% of the initial value is observed. Treatment with norflurazon, an inhibitor that blocks the synthesis of coloured carotenoids, demonstrates a much stronger degradation of the existing carotenoids, which was more pronounced at high light intensities. However, the amounts of the accumulating precursor phytoene reveal that de novo biosynthesis is enhanced under high-light conditions. Nevertheless, this upregulated synthesis cannot fully compensate for carotenoid loss by photodegradation. The potential of the carotenoids from Synechocystis to protect against photosensitized and radical peroxidation reactions has been evaluated. It is found that myxoxanthophyll, which is preferentially synthesized in high light, exhibits the strongest protection and that echinenone is the most stable carotenoid under photo-oxidative conditions.
ISSN:1011-1344
1873-2682
DOI:10.1016/S1011-1344(99)00094-9