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- Title
Diurnal Rhythm of β-Carotene in Photosynthetic Alga Gonyaulax polyedra.
- Authors
Di Mascio, Paolo; Hollnagel, Heloisa C.; Speransa, Marcia; Colepicolo, Pio
- Abstract
Carotenoids comprise one of the most widespread classes of pigments found in nature. Polyene pigments from the dinoflagellate Gonyaulax polyedra were extracted every hour over a 24 hour period and the levels of β-carotene during the day-phase were found to be twice as high as during the night-phase period. Using the thermal decomposition of 1,4-dimethylnaphthalene endoperoxide, the overall quenching ability of β-carotene and G. polyedra carotenoids of singlet oxygen were found to be 2.04 109M-1s-1 and 4.75 x 109M-1s-1 respectively. Such a high quenching rate constant suggest a possible role for carotenoids as effective singlet oxygen quenchers in G. polyedra. The dose response curve for light-induced carotenoid synthesis shows a linear response up to 45 minutes of light exposure, after which night phase cells contain the same levels of β-carotene as day-phase cells. Cells exposed to light pulses at different times during the night period display the highest β-carotene induction in the middle of the night.
- Publication
Biological Chemistry, 1995, Vol 376, Issue 5, p297
- ISSN
1431-6730
- Publication type
Article