Photooxidative damage to the cyanobacterium Spirulina platensis mediated by singlet oxygen
- Cite this article as:
- Singh, D.P., Singh, N. & Verma, K. Current Microbiology (1995) 31: 44. doi:10.1007/BF00294633
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Experiments on the specific growth rate, bleaching of pigments, O2 evolution, lipid peroxidation, and loss of sulfhydryl (-SH) content in response to the varying light intensities (2–28 W/m2) suggested that photodamage to the Spirulina cells was maximum at or beyond the photosynthesis saturating light intensity (12 W/m2). However, photobleaching of the chlorophyll a was relatively higher than β carotenoid. The results on the N,N-dimethyl-p-nitrosoaniline (RNO) bleaching in the presence of oxygen radical quenchers exhibited maximum effect of sodium azide and indicated about the generation of singlet oxygen. The chlorophyll a-sensitized production of singlet oxygen by a type II reaction cannot be ruled out because of maximum oxidative damage to the cells at or beyond the photosynthesis saturating light intensity, i.e., 12 W/m2, when the availability of triplet chlorophyll is maximum.