Abstract
The unicellular green alga Dunaliella bardawil exhibits typical responses to excessive light when starved for sulfate under normal light (60 [mu]E m-2 s-1) but not under low light (14 [mu]E m-2 s-1). Algae were analyzed during several days of sulfate starvation for nonphotochemical quenching of chlorophyll fluorescence in the absence or presence of the uncouplers SF-6847 (SF) or carbonyl cyanide p- trifluoromethoxyphenyl hydrazone. Parallel analyses followed two light-stress responses: (a) violaxanthin conversion to zeaxanthin and (b) accumulation of Cbr, a protein analogous to plant early-light-induced proteins and implicated in zeaxanthin binding. In cells starved under normal light SF inhibited nonphotochemical quenching during the first 24 h, but not from 40 h onward. In cells starved under low light SF inhibited nonphotochemical quenching throughout the starvation period. Under normal light accumulation of zeaxanthin was nearly maximal by 24 h, but Cbr was fully induced only by 40h. Under low light zeaxanthin accumulated slowly but no Cbr was evident. These results suggest that during exposure to excessive light, the initial pH gradient-dependent, Cbr-independent mode of nonphotochemical quenching is modified to become less dependent on pH gradient and requires Cbr.
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- Adamska I., Kloppstech K., Ohad I. UV light stress induces the synthesis of the early light-inducible protein and prevents its degradation. J Biol Chem. 1992 Dec 5;267(34):24732–24737. [PubMed] [Google Scholar]
- Green B. R., Pichersky E., Kloppstech K. Chlorophyll a/b-binding proteins: an extended family. Trends Biochem Sci. 1991 May;16(5):181–186. doi: 10.1016/0968-0004(91)90072-4. [DOI] [PubMed] [Google Scholar]
- Grimm B., Kloppstech K. The early light-inducible proteins of barley. Characterization of two families of 2-h-specific nuclear-coded chloroplast proteins. Eur J Biochem. 1987 Sep 15;167(3):493–499. doi: 10.1111/j.1432-1033.1987.tb13364.x. [DOI] [PubMed] [Google Scholar]
- Horton P., Ruban A. V., Walters R. G. Regulation of Light Harvesting in Green Plants (Indication by Nonphotochemical Quenching of Chlorophyll Fluorescence). Plant Physiol. 1994 Oct;106(2):415–420. doi: 10.1104/pp.106.2.415. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Levy H., Tal T., Shaish A., Zamir A. Cbr, an algal homolog of plant early light-induced proteins, is a putative zeaxanthin binding protein. J Biol Chem. 1993 Oct 5;268(28):20892–20896. [PubMed] [Google Scholar]
- Pick U. Liposomes with a large trapping capacity prepared by freezing and thawing of sonicated phospholipid mixtures. Arch Biochem Biophys. 1981 Nov;212(1):186–194. doi: 10.1016/0003-9861(81)90358-1. [DOI] [PubMed] [Google Scholar]
- Pick U., Weiss M., Rottenberg H. Anomalous uncoupling of photophosphorylation by palmitic acid and by gramicidin D. Biochemistry. 1987 Dec 15;26(25):8295–8302. doi: 10.1021/bi00399a041. [DOI] [PubMed] [Google Scholar]
- Ruban A. V., Horton P. An Investigation of the Sustained Component of Nonphotochemical Quenching of Chlorophyll Fluorescence in Isolated Chloroplasts and Leaves of Spinach. Plant Physiol. 1995 Jun;108(2):721–726. doi: 10.1104/pp.108.2.721. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Terada H. Some biochemical and physiochemical properties of the potent uncoupler SF 6847 (3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile). Biochim Biophys Acta. 1975 Jun 17;387(3):519–532. doi: 10.1016/0005-2728(75)90090-0. [DOI] [PubMed] [Google Scholar]