Altritol synthesis by Notheia anomala

The linear hexitol altritol has only been identified in six genera, all of them in the order Fucales of the brown algae. Five of these genera are clos ely related according to molecular phylogenetic and other data, while the s ixth (Notheia) is an obligate epiphyte on two other altritol-containing gen era with which it is symphanic. The possibility that Nothela obtains altrit ol from the algae on which it is epiphytic rather than by synthesizing altr itol independently was investigated by supplying C-13-inorganic carbon in t he light followed by mass spectrometric and nuclear magnetic resonance anal ysis. Notheia separated from the phorophyte Hormosira during exposure to C- 13 showed C-13 enrichment in both altritol and mannitol, while the Hormosir a only showed significant labelling of mannitol. These data show that altri tol can be synthesized by Notheia, with implications for the number of gain s and losses of the capacity to synthesize altritol in the evolution of the Fucales. (C) 2001 Published by Elsevier Science Ltd.