Note
The influence of nitrogen availability on the chemical structure of agar polymers isolated from Gracilaria verrucosa strain G-16 was ascertained by sequential solvent extraction and carbon 13 nuclear magnetic resonance (13C NMR) spectroscopy. Agar isolated from G. verrucosa strain G-16 cultured under nitrogen limited conditions showed large non-polar components but produced spectra indicative of only minor amounts of methylation.