This award will support collaborative research between Dr. Michael Gretz of George Mason University and Dr. Richard Furneauz of the New Zealand Department of Scientific and Industrial Research (DSIR). Extracellular matrix polysac- charides of red algae include the commercially important carrageenans and agarocolloids as well as cellulose, xylans, mannans, and complex heteropolysaccharides. Due in part to the commercial significance of these compounds and their derivatives as gelling, emulsifying and sizing agents, much is known of the chemistry of these polymers from selected organisms. Relatively little is known, however, about the distribution of these and related natural compounds among major groups of the red algae. A more detailed survey of this plant division is therefore needed. The objective of this research is comparative biochemical analysis of cell wall polymers of New Zealand and North American red algae using techniques recently developed in New Zealand for methylation analysis (gas chromatography/mass spectrometry), as well as nuclear magnetic resonance (NMR) and x-ray diffraction analysis. A second objective is to better understand the biosynthetic pathways to these polysacchardides using a unique approach currently being developed in the United States incorporating 13C-labelling of precursor molecules coupled with methylation analysis and NMR. The project represents excellent collaboration between the U.S. and New Zealand group in utilizing their complementary skills in algal polysaccharide research. This is important fundmental work on the biochemistry of red algal polysaccrides, and has the potential for discovery of sources of additional natural products.