UPTAKE AND METABOLISM OF EXOGENOUSLY SUPPLIED SUGARS BY BROWN ALGAE

In nine of eleven species of brown algae tested, much of the 14C‐glucose taken up from aqueous media was readily leached out again during subsequent washing in ice‐cold seawater. Whilst none of the unleachable fraction was converted to 14C‐mannitol, a considerable proportion was incorporated into insoluble glucose polymers and some was lost in respiration. Two species—Ascophyllum nodosum and Pelvetia canaliculata—were very different in that very little accumulated 14C‐glucose could be leached out. Most of the 14C‐glucose in the tissues of these two algae was rapidly converted to 14C‐mannitol, the remainder being either incorporated into insoluble compounds or respired. These two species were also able to convert exogenously supplied 14C‐mannose to mannitol, and Pelvetia incorporated much 14C from exogenous mannitol into a disaccharide compound. Fucus, as a representative of the other species investigated, was unable to metabolize either exogenous mannose or mannitol. None of the eleven species converted either galactose or fructose, supplied exogenously, to mannitol. Copyright © 1969, Wiley Blackwell. All rights reserved