Abstract
Light-dependent 14CO2 fixation by the algae of Diplosoma virens (Hartmeyer) ranged between about 3 and 27 μmoles mg-1 chlorophyll h-1. The principal first products of 14C fixation were 3-phosphoglyceric acid and phosphorylated sugars, indicating that ribulose bisphosphate carboxylase was the primary carboxylation enzyme. The activity of this enzyme in crude extracts of the algae was 4 to 6 μmoles CO2 mg-1 chlorophyll h-1. The principal end product of 14C fixation by these algae in the ascidian host was a water-soluble oligosaccharide which was an α-1,4-glucan. A maximum of 7% of the 14C fixed was found in insoluble materials of the algae or its host after 60 min 14CO2 fixation. Whether the α-1,4-glucan is a product of algal or animal metabolism remains to be determined.
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Communicated by G.F. Humphrey, Sydney
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Akazawa, T., Newcomb, E.H. & Osmond, C.B. Pathway and products of CO2-fixation by green prokaryotic algae in the cloacal cavity of Diplosoma virens . Mar. Biol. 47, 325–330 (1978). https://doi.org/10.1007/BF00388923
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DOI: https://doi.org/10.1007/BF00388923