Labeled, incorporation into polysaccharides

From this brief survey, it is seen that there were few features of carbohydrate metabolism in plants that escaped Hassid s touch, and much that we now know about the role of sugar nucleotides in the interconversion of carbohydrates in plants is a direct result of his persistent effort. From the incorporation of labelled precursors into monosaccharides, to the conversion of the monosaccharides into their glycosyl phosphates, to the action of the pyrophosphorylases in the synthesis of glycosyl esters of nucleoside pyrophosphates, to the interconversion of the resulting sugar nucleotides, to the polymerization of the activated monosaccharides to yield disaccharides and the homopolysaccharides, and, finally, to the modification of the polysaccharides by methylation—in summary, to almost every aspect... 

Cytochemical staining, by a method involving oxidation with periodate and reaction with thiosemicarbazide and osmium tetroxide, has revealed the presence of polysaccharide lamellae on the surface of the cell membrane of Claviceps purpurea.The membranous clusters in vacuolar bodies of the endoplasmic reticulum membranes, tonoplasts, and cytoplasmic membranes are covered with these lamellae. Somatic and metabolic polysaccharides composed of D-mannose and L-rhamnose have been isolated from Certocystic stenoceras and Sporotrichum schenckii , chemical and immunological analyses indicated close similarities in their structures. When pseudoplasmodia of Dictyostelium discoideum were incubated with 2-acetamido-2-deoxy-D-[ H]glucose, the label was incorporated into a polysaccharide in the slime sheath. The incorporated label disappeared... 

Particulate preparations from com shoots readily incorporate 14C-labeled D-xylose from UDP-D-xylose-14C into a polysaccharide in which the D-xylose residues are combined by / -l,4-D-xylosyl bonds (31). It was shown that this polysaccharide, similar to natural plant xylan, contains a small proportion of L-arabinose units which have the furanose configuration. 

The priming capacity of the polysaccharide fraction was confirmed by labeling experiments. Incubation of the purifie cytosolic phosphory-lase isozyme with the polysaccahride fraction and u-glucose 1-phosphate resulted in an effective incorporation of labeled glucosyl residues into the high molecular weight polysaccharide (data not shown). 

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