title: Biosynthesis of 13-desmethyl spirolide C by the dinoflagellate Alexandrium ostenfeldii.
abstract: Biosynthetic origins of the cyclic imine toxin 13-desmethyl spirolide C were determined by supplementing cultures of the toxigenic dinoflagellate Alexandrium ostenfeldii with stable isotope-labeled precursors [1,2-13C2]acetate, [1-13C]acetate, [2-13CD3]acetate, and [1,2-13C2,15N]glycine and measuring the incorporation patterns by 13C NMR spectroscopy. Despite partial scrambling of the acetate labels, the results show that most carbons of the macrocycle are polyketide-derived and that glycine is incorporated as an intact unit into the cyclic imine moiety. This work represents the first conclusive evidence that such cyclic imine toxins are polyketides and provides support for biosynthetic pathways previously defined for other polyether dinoflagellate toxins.
authors.affiliation: Institute for Marine Biosciences, National Research Council of Canada, 1411 Oxford Street, Halifax NS, Canada B3H 3Z1.
authors.forename: Shawna L
authors.initials: SL
authors.lastname: MacKinnon
authors.forename: Allan D
authors.initials: AD
authors.lastname: Cembella
authors.forename: Ian W
authors.initials: IW
authors.lastname: Burton
authors.forename: Nancy
authors.initials: N
authors.lastname: Lewis
authors.forename: Patricia
authors.initials: P
authors.lastname: LeBlanc
authors.forename: John A
authors.initials: JA
authors.lastname: Walter
mesh_terms: D000818:Animals; D002247:Carbon Isotopes; D004141:Dinoflagellida / Q000737:chemistry / Q000378:metabolism*; D047028:Macrocyclic Compounds / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008387:Marine Toxins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D015394:Molecular Structure; D012680:Sensitivity and Specificity; D013141:Spiro Compounds / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013237:Stereoisomerism
chemical_list: C517170:13-desmethylspirolide C; D002247:Carbon Isotopes; D047028:Macrocyclic Compounds; D008387:Marine Toxins; D013141:Spiro Compounds