Pyruvated carrageenans from Solieria robusta and its adelphoparasite Tikvahiella candida

Solieria, the type genus of the commercially important red algal family Sol ieriaceae (Gigartinales), contains seven or eight species, three of which a re represented in Australia. The cell-wall galactans of the most common Aus tralian Solieria species, S. robusta (Greville) Kylin, were analysed by a c ombination of compositional assays, linkage analysis, and Fourier transform infrared (FTIR) and C-13 nuclear magnetic resonance (NMR) spectroscopy. Th ey are shown to be composed predominantly of carrabiose 2,4'-disulphate uni ts (the repeating unit of iota-carrageenan) and a significant proportion of 4',6'-pyruvated carrabiose 2-sulphate units. The constituent sugars, pyruv ate content, FTIR spectrum, and linkage and substitution patterns of the ga lactans from Tikvahiella candida Kraft et Gabrielson, an adelphoparasite of Solieria robusta, closely resemble those of its host and furnish evidence in support of a close phylogenetic relationship between the two species.