title: Metal complexes and free radical toxins produced by Pfiesteria piscicida.
abstract: Metal-containing organic toxins produced by Pfiesteria piscicida were characterized, for the first time, by corroborating data obtained from five distinct instrumental methods: nuclear magnetic resonance spectroscopy (NMR), inductively coupled plasma mass spectrometry (ICP-MS), liquid chromatography particle beam glow discharge mass spectrometry (LC/PB-G DMS), electron paramagnetic resonance spectroscopy (EPR), and X-ray absorption spectroscopy (XAS). The high toxicity of the metal-containing toxins is due to metal-mediated free radical production. This mode of activity explains the toxicity of Pfiesteria, as well as previously reported difficulty in observing the molecular target, due to the ephemeral nature of radical species. The toxins are highly labile in purified form, maintaining activity for only 2-5 days before all activity is lost. The multiple toxin congeners in active extracts are also susceptible to decomposition in the presence of white light, pH variations, and prolonged heat. These findings represent the first formal isolation and characterization of a radical forming toxic organic-ligated metal complex isolated from estuarine/marine dinoflagellates. These findings add to an increased understanding regarding the active role of metals interacting with biological systems in the estuarine environment, as well as their links and implications to human health.
authors.affiliation: Center for Coastal Environmental Health and Biomolecular Research, National Oceanic and Atmospheric Administration National Ocean Service, Hollings Marine Laboratory, Charleston, South Carolina 29412, USA. Peter.Moeller@noaa.gov
authors.forename: Peter D R
authors.initials: PD
authors.lastname: Moeller
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Beauchesne
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Huncik
authors.forename: W Clay
authors.initials: WC
authors.lastname: Davis
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Christopher
authors.forename: Pamela
authors.initials: P
authors.lastname: Riggs-Gelasco
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Gelasco
mesh_terms: D000818:Animals; D003300:Copper / Q000032:analysis* / Q000737:chemistry; D005609:Free Radicals / Q000032:analysis; D007501:Iron / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008387:Marine Toxins / Q000737:chemistry / Q000302:isolation & purification*; D008958:Models, Molecular; D020045:Pfiesteria piscicida; D013455:Sulfur / Q000032:analysis
chemical_list: D005609:Free Radicals; D008387:Marine Toxins; D013455:Sulfur; D003300:Copper; D007501:Iron