Photosynthetic metabolism in the cyanophyta Oscillatoria rubescens D.C. II. Carbon metabolism under nitrogen starvation

Short term 14C labelling experiments and enzymatic activities related to primary pathways of photosynthesis have been studied in the cyanophytaOscillatoria rubescens D.C. from axenic cyclostat cultures. Responses of samples from cultures with different amounts of nitrogen are presented and compared....

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Bibliographic Details
Published in:Archives of microbiology 1982, Vol.131 (2), p.107-111
Main Authors: Feuillade, J, Feuillade, M, Jolivet, E
Format: Article
Language:English
Subjects:
Cyanobacteria
Life Sciences
plant biochemistry
plant physiology
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Summary:Short term 14C labelling experiments and enzymatic activities related to primary pathways of photosynthesis have been studied in the cyanophytaOscillatoria rubescens D.C. from axenic cyclostat cultures. Responses of samples from cultures with different amounts of nitrogen are presented and compared. Variations in photosynthetic pigments are used to quantify the degree of nitrogen starvation at different levels. PEPcarboxylase activity remains low and is not affected by nitrogen starvation. RuBPcarboxylase activity is lowered to nearly two thirds of its normal metabolic rate by starvation but PEPcarboxykinase and aspartate aminotransferase activities are significantly higher in this case. Malate dehydrogenase is slightly altered and malic enzyme is never active. Starved algae replaced in fresh complete media fix rapidly14C in nitrogen compounds such as amino acids. Results are discussed in regard to both physiological and ecological characteristics ofO. rubescens. PEPcarboxykinase can play a role in making efficient use of HCO 3 - .
ISSN:0302-8933
1432-072X
DOI:10.1007/BF01053990