title: Karmitoxin: An Amine-Containing Polyhydroxy-Polyene Toxin from the Marine Dinoflagellate Karlodinium armiger.
abstract: Marine algae from the genus Karlodinium are known to be involved in fish-killing events worldwide. Here we report for the first time the chemistry and bioactivity of a natural product from the newly described mixotrophic dinoflagellate Karlodinium armiger. Our work describes the isolation and structural characterization of a new polyhydroxy-polyene named karmitoxin. The structure elucidation work was facilitated by use of13C enrichment and high-field 2D NMR spectroscopy, where1H-13C long-range correlations turned out to be very informative. Karmitoxin is structurally related to amphidinols and karlotoxins; however it differs by containing the longest carbon-carbon backbone discovered for this class of compounds, as well as a primary amino group. Karmitoxin showed potent nanomolar cytotoxic activity in an RTgill-W1 cell assay as well as rapid immobilization and eventual mortality of the copepod Acartia tonsa, a natural grazer of K. armiger.
authors.affiliation: Department of Biotechnology and Biomedicine, Technical University of Denmark , Søltofts Plads Building 221, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Silas Anselm
authors.initials: SA
authors.lastname: Rasmussen
authors.affiliation: Marine Biological Section, Department of Biology, University of Copenhagen , Strandpromenaden 5, DK-3000 Helsingør, Denmark.
authors.forename: Sofie Bjørnholt
authors.initials: SB
authors.lastname: Binzer
authors.affiliation: Department of Chemistry, Technical University of Denmark , Kemitorvet Building 207, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Casper
authors.initials: C
authors.lastname: Hoeck
authors.affiliation: Department of Chemistry, Technical University of Denmark , Kemitorvet Building 207, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Sebastian
authors.identifier: 0000-0003-3761-3217
authors.initials: S
authors.lastname: Meier
authors.affiliation: Faculty of Pharmaceutical Sciences, University of São Paulo , São Paulo, 05508-000, Brazil.
authors.forename: Livia Soman
authors.initials: LS
authors.lastname: de Medeiros
authors.affiliation: National Veterinary Institute, Technical University of Denmark , Bülowsvej 27, DK-1870 Frederiksberg C, Denmark.
authors.forename: Nikolaj Gedsted
authors.initials: NG
authors.lastname: Andersen
authors.affiliation: University of Maryland Center for Environmental Research , Institute of Marine and Environmental Technology, 701 E. Pratt Street, Baltimore, Maryland 21202, United States.
authors.forename: Allen
authors.initials: A
authors.lastname: Place
authors.affiliation: Department of Biotechnology and Biomedicine, Technical University of Denmark , Søltofts Plads Building 221, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Kristian Fog
authors.initials: KF
authors.lastname: Nielsen
authors.affiliation: Marine Biological Section, Department of Biology, University of Copenhagen , Strandpromenaden 5, DK-3000 Helsingør, Denmark.
authors.forename: Per Juel
authors.initials: PJ
authors.lastname: Hansen
authors.affiliation: Department of Biotechnology and Biomedicine, Technical University of Denmark , Søltofts Plads Building 221, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Thomas Ostenfeld
authors.identifier: 0000-0002-3362-5707
authors.initials: TO
authors.lastname: Larsen
mesh_terms: D000588:Amines / Q000737:chemistry*; D000818:Animals; D004141:Dinoflagellida / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008387:Marine Toxins / Q000737:chemistry*; D015394:Molecular Structure; D011090:Polyenes / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000588:Amines; D008387:Marine Toxins; D011090:Polyenes; C000622055:karmitoxin