Biosynthesis of the neurotoxin domoic acid by the marine diatom Nitzschia pungens forma multiseries, determined with [13C]-labelled precursors and nuclear magnetic resonance

Labelling experiments with [1-13C]acetate and [1,2-13C]acetate provide evidence that the neurotoxin domoic acid, produced by the diatom Nitzschia pungens, is derived by the novel condensation of a geranyl unit with an activated citric acid cycle derivative and subsequent cyclisation to form a proline ring system.