title: Toxicity screening of 13 Gambierdiscus strains using neuro-2a and erythrocyte lysis bioassays.
abstract: Species in the epi-benthic dinoflagellate genus Gambierdiscus produce ciguatoxins (CTXs) and maitotoxins (MTXs), which are among the most potent marine toxins known. Consumption of fish contaminated with sufficient quantities of CTXs causes Ciguatera Fish Poisoning (CFP), the largest cause of non-bacterial food poisoning worldwide. Maitotoxins, which can be found in the digestive system of fish, could also contribute to CFP if such tissues are consumed. Recently, an increasing number of Gambierdiscus species have been identified; yet, little is known about the variation in toxicity among Gambierdiscus strains or species. This study is the first assessment of relative CTX- and MTX-toxicity of Gambierdiscus species from areas as widespread as the North-Eastern Atlantic Ocean, Pacific Ocean and the Mediterranean Sea. A total of 13 strains were screened: (i) seven Pacific strains of G. australes, G. balechii, G. caribaeus, G. carpenteri, G. pacificus, G. scabrosus and one strain of an undetermined species (Gambierdiscus sp. Viet Nam), (ii) five strains from the North-Eastern Atlantic Ocean (two G. australes, a single G. excentricus and two G. silvae strains), and (iii) one G. carolinianus strain from the Mediterranean Sea. Cell pellets of Gambierdiscus were extracted with methanol and the crude extracts partitioned into a CTX-containing dichloromethane fraction and a MTX-containing aqueous methanol fraction. CTX-toxicity was estimated using the neuro-2a cytoxicity assay, and MTX-toxicity via a human erythrocyte lysis assay. Different species were grouped into different ratios of CTX- and MTX-toxicity, however, the ratio was not related to the geographical origin of species (Atlantic, Mediterranean, Pacific). All strains showed MTX-toxicity, ranging from 1.5 to 86pg MTX equivalents (eq) cell-1. All but one of the strains showed relatively low CTX-toxicity ranging from 0.6 to 50 fg CTX3C eq cell-1. The exception was the highly toxic G. excentricus strain from the Canary Islands, which produced 1426 fg CTX3C eq cell-1. As was true for CTX, the highest MTX-toxicity was also found in G. excentricus. Thus, the present study confirmed that at least one species from the Atlantic Ocean demonstrates similar toxicity as the most toxic strains from the Pacific, even if the metabolites in fish have so far been shown to be more toxic in the Pacific Ocean.
authors.affiliation: Ifremer, Phycotoxins Laboratory, rue de l'Ile d'Yeu, BP 21105, F-44311 Nantes, France. Electronic address: francesco.pisapia@ifremer.fr.
authors.forename: Francesco
authors.initials: F
authors.lastname: Pisapia
authors.affiliation: National Oceanic and Atmospheric Administration, National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Fisheries and Habitat Research (CCFHR),101 Pivers Island Road, Beaufort, NC 28516, USA.
authors.forename: William C
authors.initials: WC
authors.lastname: Holland
authors.affiliation: National Oceanic and Atmospheric Administration, National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Fisheries and Habitat Research (CCFHR),101 Pivers Island Road, Beaufort, NC 28516, USA.
authors.forename: D Ransom
authors.initials: DR
authors.lastname: Hardison
authors.affiliation: National Oceanic and Atmospheric Administration, National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Fisheries and Habitat Research (CCFHR),101 Pivers Island Road, Beaufort, NC 28516, USA.
authors.forename: R Wayne
authors.initials: RW
authors.lastname: Litaker
authors.affiliation: Instituto Español de Oceanografía (IEO), Centro Oceanográfico de Vigo, Subida a Radio Faro 50, 36390 Vigo, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Fraga
authors.affiliation: LAQUES (Laboratory of Aquatic Environmental Science), Faculty of Agriculture, Kochi University, 200 Otsu, Monobe, Nankoku, Kochi, 783-8502, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nishimura
authors.affiliation: LAQUES (Laboratory of Aquatic Environmental Science), Faculty of Agriculture, Kochi University, 200 Otsu, Monobe, Nankoku, Kochi, 783-8502, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Adachi
authors.affiliation: Institute of Oceanography, VAST, Cauda 01, Vinh Nguyen, Nha Trang, Viet Nam.
authors.forename: Lam
authors.initials: L
authors.lastname: Nguyen-Ngoc
authors.affiliation: Ifremer, Phycotoxins Laboratory, rue de l'Ile d'Yeu, BP 21105, F-44311 Nantes, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Séchet
authors.affiliation: Ifremer, Phycotoxins Laboratory, rue de l'Ile d'Yeu, BP 21105, F-44311 Nantes, France.
authors.forename: Zouher
authors.initials: Z
authors.lastname: Amzil
authors.affiliation: LUNAM, University of Nantes, MMS EA2160, Pharmacy Faculty, 9 rue Bias, F-44035 Nantes, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Herrenknecht
authors.affiliation: Ifremer, Phycotoxins Laboratory, rue de l'Ile d'Yeu, BP 21105, F-44311 Nantes, France.
authors.forename: Philipp
authors.initials: P
authors.lastname: Hess
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D036841:Ciguatera Poisoning; D002922:Ciguatoxins / Q000032:analysis / Q000633:toxicity; D004141:Dinoflagellida / Q000378:metabolism*; D004912:Erythrocytes / Q000187:drug effects; D008387:Marine Toxins / Q000032:analysis* / Q000633:toxicity; D035964:Oxocins / Q000032:analysis / Q000633:toxicity; D010802:Phylogeny; D000095702:Polyether Toxins
chemical_list: D002922:Ciguatoxins; D008387:Marine Toxins; D035964:Oxocins; C020394:maitotoxin; D000095702:Polyether Toxins
keywords: Ciguatera fish poisoning; Ciguatoxins; Erythrocyte lysis assay; Gambierdiscus; Maitotoxins; Neuro-2a assay