The biosynthesis of the oligosaccharide chains of glycoproteins in cultures of Koliella antarctica (Klebsormidiales), a green filamentous microalga collected from samples of seawater near the Italian station of Terra Nova (Ross Sea, Antarctica), has been studied by using D-[U-C-14] glucosamine as a tracer. To characterize the oligosaccharide moieties of Koliella glycoproteins, immunolabelling experiments with different lectins have also been performed. The use of radioactive tracer has shown that exogenously supplied D-[U-C-14] glucosamine is taken up by the microalga and sequentially metabolized to soluble radioactive UDP-N-acetylglucosamine and UDP-N-acetylgalactosamine. N-acetylglucosamine and N-acetylgalactosamine residues were incorporated mainly into the oligosaccharide chains of soluble and membrane-bound glycoproteins; the lowest amount of radioactive N-acetylhexosamines was detected in covalently and non-covalently linked cell-wall glycoproteins. Immunolabelling experiments with different lectins have shown similarities and differences among the patterns of soluble, membrane-bound and cell-wall glycoproteins. A peculiar characteristic of these microalgae is the presence of N-acetylgalactosamine residues as a component of the oligosaccharide chains of intracellular and cell wall N-linked glycoproteins.

Biosynthesis and characterization of glycoproteins in Koliella antarctica (Klebsormidiales, Chlorophyta)

ANDREOLI, CARLO;
2006

Abstract

The biosynthesis of the oligosaccharide chains of glycoproteins in cultures of Koliella antarctica (Klebsormidiales), a green filamentous microalga collected from samples of seawater near the Italian station of Terra Nova (Ross Sea, Antarctica), has been studied by using D-[U-C-14] glucosamine as a tracer. To characterize the oligosaccharide moieties of Koliella glycoproteins, immunolabelling experiments with different lectins have also been performed. The use of radioactive tracer has shown that exogenously supplied D-[U-C-14] glucosamine is taken up by the microalga and sequentially metabolized to soluble radioactive UDP-N-acetylglucosamine and UDP-N-acetylgalactosamine. N-acetylglucosamine and N-acetylgalactosamine residues were incorporated mainly into the oligosaccharide chains of soluble and membrane-bound glycoproteins; the lowest amount of radioactive N-acetylhexosamines was detected in covalently and non-covalently linked cell-wall glycoproteins. Immunolabelling experiments with different lectins have shown similarities and differences among the patterns of soluble, membrane-bound and cell-wall glycoproteins. A peculiar characteristic of these microalgae is the presence of N-acetylgalactosamine residues as a component of the oligosaccharide chains of intracellular and cell wall N-linked glycoproteins.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/1563673
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