Paramylon synthesis by Euglena gracilis photoheterotrophically grown under low O 2 pressure: Description of a mitochloroplast complex

Special culture conditions for Euglena gracilis Z and ZR are described. They induce interactions between the chloroplast and mitochondrial metabolisms leading to paramylon synthesis. When grown in continuous light under pure nitrogen and in the presence of lactate as the sole carbon source, sugar sy...

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Bibliographic Details
Published in:Planta 1981-01, Vol.153 (1), p.6-13
Main Authors: Calvayrac, R., Laval-Martin, D., Briand, J., Farineau, J.
Format: Article
Language:English
Subjects:
Cell growth
Chloroplasts
Cultured cells
Euglena
Lactates
Mitochondria
Nitrogen
Oxygen
Plant cells
Plants
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Description
Summary:Special culture conditions for Euglena gracilis Z and ZR are described. They induce interactions between the chloroplast and mitochondrial metabolisms leading to paramylon synthesis. When grown in continuous light under pure nitrogen and in the presence of lactate as the sole carbon source, sugar synthesis occurs during the first 24 h of culture with the participation of both mitochondria (using lactate) and of chloroplasts (fixing CO2 from lactate decarboxylation). The activities of ribulose bisphosphate carboxylase, phosphoenolpyruvate carboxylase, and phosphoenolpyruvate carboxykinase are very high and mitochondria and chloroplasts develop then a common network of vesicles in which paramylon grains can be seen. Electron micrographs demonstrate membrane continuity between the two types of organelles. Occasionally the mitochondrial matrix and the chloroplast stroma are separated by only a unit membrane.
ISSN:0032-0935
1432-2048
DOI:10.1007/BF00385311