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CHEMISTRY, PROPERTIES, AND PHYLOGENETIC IMPLICATIONS OF THE METHYLATED CARRAGEENANS FROM RED ALGAE OF THE GENUS ARESCHOUGIA (ARESCHOUGIACEAE, GIGARTINALES, RHODOPHYTA)
Author(s) -
Chiovitti Anthony,
Kraft Gerald T.,
Bacic Antony,
Craik David J.,
Liao MingLong
Publication year - 2001
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1046/j.1529-8817.2001.01086.x
Subject(s) - gigartinales , carrageenan , biology , polysaccharide , botany , genus , algae , biochemistry
The three Australian‐endemic species comprising the genus Areschougia have been examined to determine the structure of their nonfibrillar wall components. The polysaccharide extracted from the most widely distributed species, A. congesta (Turner) J. Agardh, was shown by compositional analyses, Fourier transform infrared (FTIR) spectroscopy, linkage analysis, and 13 C‐NMR spectroscopy to be a carrageenan composed predominantly of the repeating disaccharides 6′‐ O ‐meth‐ ylcarrabiose 2,4′‐disulfate, carrabiose 2,4′‐disulfate (the repeating unit of ι‐carrageenan), 4′,6′‐ O ‐(1‐carboxyethylidene)carrabiose 2‐sulfate, and 6′‐ O ‐methylcarrabiose 2‐sulfate. The carrageenan also contained small amounts of 4‐linked Gal p residues, some bearing methyl ether substitution at O‐3 and some possibly bearing sulfate ester and/or glycosyl substitutions at O‐3. The A. congesta carrageenan had unique rheological properties, its gels having some similarities to those of commercial ι‐carrageenan but with the viscosity of commercial λ‐carrageenan. Polysaccharides from A. ligulata Harvey ex J. Agardh and A. stuartii Harvey were shown by constituent sugar and FTIR analyses to be sulfated galactans rich in mono‐ O ‐methylgalactose. The carrageenan structures of Areschougia spp. were consistent with those of the genera Rhabdonia , Erythroclonium , and Austroclonium , the other genera constituting the family Areschougiaceae.