Polysaccharides from the green seaweed Codium decorticatum: Structure and cell wall distribution

Abstract

The cell wall polysaccharides from Codium decorticatum and their assembly were studied and these results were compared with those obtained previously for this genus. The water soluble polysaccharides are: i) Pyruvylated and sulfated 3- and 6-linked B-D-galactans with sulfate mainly on C-4 and also on C-6. Pyruvate ketals are linked to O-3 and O-4 of terminal B-D-galactose or O-4 and O-6 of 3-linked B-D-galactose. ii) Sulfated 3-linked B-L-arabinans substituted on C-2 or C-2 and C-4 predominantly with sulfate, but also with single stubs of arabinose, and iii) 4-Linked B-D-mannans with a low degree of sulfation on C-2. The whole polysaccharide system comprises 6.9 % of sulfated polysaccharides and 32.9 % of fibrillar polysaccharides, mostly insoluble mannans. By in situ localization it was possible to detect two similar fibrillar layers separated by a zone rich in charged polymers. Besides, arabinogalactan proteins co-localized with the fibrillar components.