title: The novel ovatoxin-g and isobaric palytoxin (so far referred to as putative palytoxin) from Ostreopsis cf. ovata (NW Mediterranean Sea): structural insights by LC-high resolution MS(n.).
abstract: Blooms of the benthic dinoflagellate Ostreopsis cf. ovata are a concern in the Mediterranean Sea, since this species produces a wide range of palytoxin-like compounds listed among the most potent marine toxins. This study focused on two analogs of palytoxin found in cultures of six strains of O. cf. ovata isolated from the south of Catalonia (NW Mediterranean Sea). In addition to some already known ovatoxins, our strains produced two minor compounds, ovatoxin-g and the so far called putative palytoxin, whose structures had not been elucidated before. Insufficient quantity of these compounds impeded a full nuclear magnetic resonance (NMR)-based structural elucidation; thus, we studied their structure in crude algal extracts through liquid chromatography-electrospray ionization high-resolution mass spectrometry(n) (LC-ESI-HRMS(n)) in positive ion mode. Under the used MS conditions, the molecules underwent fragmentation at many sites of their backbone and a large number of diagnostic fragment ions were identified. As a result, tentative structures were assigned to both ovatoxin-g and the putative palytoxin, the latter being identified as a palytoxin isomer and re-named as  isobaric palytoxin.
authors.affiliation: IRTA, Seguiment del Medi Marí, Carretera de Poble Nou, km 5.5, 43540, Sant Carles de la Ràpita, Spain.
authors.forename: María
authors.initials: M
authors.lastname: García-Altares
authors.forename: Luciana
authors.initials: L
authors.lastname: Tartaglione
authors.forename: Carmela
authors.initials: C
authors.lastname: Dell'Aversano
authors.forename: Olga
authors.initials: O
authors.lastname: Carnicer
authors.forename: Pablo
authors.initials: P
authors.lastname: de la Iglesia
authors.forename: Martino
authors.initials: M
authors.lastname: Forino
authors.forename: Jorge
authors.initials: J
authors.lastname: Diogène
authors.forename: Patrizia
authors.initials: P
authors.lastname: Ciminiello
mesh_terms: D000178:Acrylamides / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003064:Cnidarian Venoms; D004141:Dinoflagellida / Q000737:chemistry*; D004988:Ethers, Cyclic / Q000302:isolation & purification*; D008522:Mediterranean Sea; D015394:Molecular Structure; D012623:Seawater / Q000032:analysis / Q000382:microbiology; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D000095702:Polyether Toxins
chemical_list: D000178:Acrylamides; D003064:Cnidarian Venoms; D004988:Ethers, Cyclic; C010272:palytoxin; D000095702:Polyether Toxins