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Plant Physiology 62:678-682 (1978) © 1978 American Society of Plant Biologists Light-induced Enzyme Formation in a Chlorophyll-less Mutant of Euglena gracilis 1
Department of Biology, Adelphi University, Garden City, New York 11530, Department of Biology, State University of New York, Stony Brook, New York 11794
A mutant strain, Y9, of Euglena gracilis strain Z that is unable to produce protochlorophyll or chlorophyll has been isolated following treatment of wild type cells with nalidixic acid. Dark-grown cells of the mutant contain proplastids that show only limited ultrastructural development when placed in the light. Treatment of Y9 cells with ultraviolet light brings about permanent cell bleaching with a target number similar to wild type Euglena, and with a slightly greater sensitivity to ultraviolet. Three enzymes of the reductive pentose phosphate cycle, fructose-1,6-diphosphate aldolase (class I), NADP-dependent glyceraldehyde-3-phosphate dehydrogenase, and 3-phosphoglycerate kinase, are detectable in dark-grown Y9 cells at the low concentrations characteristic of dark-grown wild type cells, and increase substantially when these cells are exposed to light. The activity of ribulose-1,5-diphosphate carboxylase increases in the light to a lesser extent. Cytochrome 552, a carrier in the photosynthetic electron transport chain, is not present in light-grown cells of Y9. The significance of this mutant for an understanding of the role of light in Euglena chloroplast development is discussed.
2 Present address: The Rockefeller University, New York, New York 10021. 1 This research was supported in part by National Science Foundation Grant BO-38262 to H. L.
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