Photosynthesis and metabolism of marine algae. VIII. Incorporation of14C into the polysaccharides metabolized byFucus vesiculosusduring pulse labeling experiments

摘要

Samples ofFucus vesiculosusfronds were allowed to assimilate14CO2for 10ensp;min and 3ensp;h. In a second experiment fronds were allowed to grow for 10ensp;min in14CO2and were then transferred to fresh medium containing12CO2. Samples were taken immediately, after 30ensp;min, and after 2ensp;h. Sequential extraction and fractionation of the polysaccharides from each of the five samples gave14C-labeled laminaran, xylogalactofucoglucuronan (A), xyloglucuronogalactofucan (B) (these polysaccharides are named in the order of the increasing proportions of their constituent sugars), fucoidan (C), alginic acid, and residual polysaccharide material containing mainly glucose with some galactose. The activities of each of the polysaccharides, the residual material, and their constituent sugars were measured. Highly active low molecular weight carbohydrates, present in the acid extract, are the suggested precursors of the polysaccharides. The fucose-containing polysaccharides represent the extremes of a family of polymers; it is postulated from these studies that (A) is transformed into fucoidan via polysaccharide (B) in this alga.