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Mass capture of small fishes with a variety of nets, traps, and weirs was widely practiced and economically important across East Polynesia at western contact. Archaeological research, however, has suggested these technologies were less important during the early settlement period and gained prominence over time. Several explanations have been proposed, including resource depression, changes in marine environments, and/or social and economic reorientations. In the Marquesas Islands, pelagic and offshore fishes were historically well represented in early assemblages relative to most Polynesian islands. Here we report on fishbone assemblages from Nuku Hiva Island that were recovered with fine mesh screens, identified using a wide range of skeletal elements, and analysed with morphometric methods. The Hakaea Beach results demonstrate that mass capture of small fishes was especially important at this locality and sustained over three early, successive occupations. These patterns may reflect the nature of the local fisheries, preferential use of high‐return capture strategies in this reef‐limited setting, and/or purposeful avoidance of ciguatera‐prone fishes and a preference for less vulnerable fishes. Overall, our findings highlight geographic variation in early Marquesan fisheries and provide archaeological evidence that mass capture technologies had an important place in the maritime toolkits of the earliest East Polynesian fishers. [ABSTRACT FROM AUTHOR]

The EuroCigua project main objective is to characterize the risk of Ciguatera Poisoning (CP) in Europe including several specific objectives: to determine the incidence of ciguatera in Europe and the epidemiological characteristics of cases; to assess the presence of ciguatoxin in food and the environment in Europe and to develop and validate methods for the detection, quantification and confirmation of the presence of ciguatoxin contaminated specimens. This report compiles the activities carried out during the EuroCigua project from the signing in April 2016 until December 2020. The present document corresponds to Deliverable No. 6: "Final Scientific Report" on Risk characterization of ciguatera food poisoning in Europe of the Specific Agreement no. 1 "MANAGEMENT AND SCIENTIFIC COORDINATION" within the Framework Partnership Agreement GP/EFSA/AFSCO/2015/03 "Risk characterization of ciguatera food poisoning in Europe". [ABSTRACT FROM AUTHOR]

The present document corresponds to the final report (deliverable No. 7) of the specific agreement (SA 2) "To determine the incidence and epidemiological characteristics of ciguatera cases in Europe" within the Framework Partnership Agreement GP/EFSA/AFSCO/2015/03 "Risk characterization of ciguatera food poisoning in Europe". This report summarises the activities performed, results and conclusions obtained in the specific agreement. The objective of the SA2 was to estimate the incidence and to describe the epidemiological characteristics of ciguatera in the EU/EEA. A protocol for a harmonized ciguatera surveillance in the European Union (EU)/Economic European Area (EEA) was elaborated. The protocol includes a ciguatera case definition and questionnaires for collecting information on ciguatera cases or outbreak. Around half of the countries answered the data call for reporting cases. Four countries reported 34 outbreaks from 2012 to 2019. Spain and Portugal reported outbreaks due to consumption of fish captured in the Canary Islands and Madeira (autochthonous outbreaks), mainly due to consumption of Seriola spp. and Ephinephelus spp. In more than half of these outbreaks, the fish was captured by sport fishing. Germany and France reported outbreaks due to consumption of fish imported from outside the EU (imported outbreaks, mainly Lutjanus spp). Spain, Germany and France reported outbreaks in travellers to tropical endemic territories (travel related outbreaks). All the outbreaks cases presented neurological symptoms, most of them had also gastrointestinal symptoms and few outbreak cases mentioned cardiovascular symptoms. Six countries (Austria, France, Germany, Portugal, Spain and Switzerland) reported 34 single cases. The incidence rate in the EU/EEA was very low (0.0054 cases per 100.000 inhabitants per year). The incidence rate in the Canary Islands was higher 0.47 cases/100.000 inhabitants. [ABSTRACT FROM AUTHOR]

The present document corresponds to Deliverable No. 10: "Final report (1st of April 2016‐31stOctober2020)." of the specific agreement "EVALUATION OF CTXs IN SEAFOOD AND THE ENVIRONMENT for the RISK ASSESSMENT OF CIGUATERA FISH POISONING (CFP), with the consequent OBTENTION OF REFERENCE MATERIAL" within the Framework Partnership Agreement GP/EFSA/AFSCO/2015/03 "Risk characterization of ciguatera food poisoning in Europe"© Institute for Research and Technology in Food and Agriculture (IRTA), Universidad de Las Palmas de Gran Canarias (ULPGC), Canary Health Service (ServicioCanario de la Salud, SCS), Instituto Português do Mar e da Atmosfera I.P (IPMA), State General Laboratory (SGL) / Ministry of Health, Aristotle University of Thessaloniki (AUT), 2021 [ABSTRACT FROM AUTHOR]

The primary objective of this specific grant was to characterize the risk associated to Ciguatera Poisoning (CP) in the EU by developing a sensitive methodology of LC‐MS/MS. The preparation of reference materials including the main ciguatoxins (CTXs) responsible for the contamination was considered the secondary objective to facilitate the implementation of the LC‐MS/MS methods in the EU laboratories to characterize this emerging risk. C‐CTX1 has been identified by LC‐MS/MS, and further confirmed by LC‐HRMS, as the main responsible for the CTX toxicity in the samples from the areas selected for this study. The low concentrations levels of CTXs found on the samples evaluated has been a key limitation for the completion of the objectives of this specific grant (SG), being necessary to establish contingency plans, not only to overcome the problems of sensitivity that might compromise the confirmation of the toxic profiles, but also to accomplish the task of preparing reference materials. The contingency plans involved the development of two complementary LC‐MS/MS approaches, as well as a methodological approach combiningLC‐MS/MS, Neuroblastoma cell assay and chromatographic fractionations (HPLC and GPC) to characterize the toxins present in the contaminated extracts. This approach has been also used for the preparation of reference materials in order to confirm the presence of the C‐CTX1 in both pure solutions of C‐CTX1 and Fish Tissue Reference materials (FTRM) containing C‐CTX1. The LC‐MS/MS analysis of Dinoflagellates samples (Gambierdiscus and Fukuyoa sp) allowed to confirm the lack of correlation between the CTXs contamination and the fish samples from the areas were these dinoflagellates were collected. In these samples, the toxicity was attributed to several Maitotoxins analogues as well as gambieric acids C and D, Gambierone, 44‐methyl gambierone, and gambieroxide that were identified by LC‐HRMS with varying degrees of confirmation in strains of Gambierdiscus and Fukuyoa from the Mediterranean Sea and North East Atlantic Ocean. [ABSTRACT FROM AUTHOR]

Liquid chromatography (LC) coupled to mass spectrometry (MS) is being widely applied as an analytical tool in the field of marine biotoxins both for regulated and for new and emerging compounds. LC-MS/MS recently became the reference method for the control of lipophilic toxins in the European Union, and new methods are being developed and optimized to extend the applicability of this technique to other toxin groups. In this work, conditions for the analysis of ciguatoxins (CTXs) by LC-MS/MS were investigated using standard solutions of CTX1B and CTX3C, which are structurally representative compounds for the rest of the main congeners of Pacific group toxins (P-CTXs). Preliminary studies were carried out for the selection of precursor and product ions used for multiple reaction monitoring. Two transitions based on the chemical structures of CTXs were set up, and mass spectrometer parameters were adjusted for selected reactions monitored. The electrospray ionization source has been carefully optimized through a design of experiments that consisted of a two-level fractional factorial design of resolution IV for the screening of adequate source conditions and of response surface designs for optimization of the main interactions between factors. The statistical approach allowed maximizing the sensitivity on the MS analyzer that provides a good specificity in P-CTX detection, which can be also used for confirmation purposes. [ABSTRACT FROM AUTHOR]

Abstract: Ciguatera fish poisoning is a seafood‐toxin illness resulting from consumption of fish contaminated with ciguatoxins. Managing ciguatera fish poisoning is complex. It is made easier, however, by local fishers from endemic areas reporting regional predictability for local fish species’ ciguatera fish poisoning risk, which the present study then tested. We investigated the prevalence of ciguatoxins in 4 commonly marketed and consumed species (Balistes vetula, Haemulon plumierii, Ocyurus chrysurus, and Epinephelus guttatus) across an oceanic gradient (north, south, east, and west) from the US Virgin Islands. Fish muscle extracts were analyzed for Caribbean ciguatoxins using an in vitro mouse neuroblastoma (N2a) cytotoxicity assay and confirmed by liquid chromatography–tandem mass spectrometry (LC‐MS/MS). Fish collected from the north location had 0 fish with detectable ciguatoxins; this site also had the greatest wave energy. Caribbean ciguatoxins in fish ranged from 0.01 to 0.11, 0.004 to 0.10, and 0.005 to 0.18 ng Caribbean ciguatoxin‐1 eq/g, from the west, east, and south respectively. Ciguatoxin‐like activity was detectable by the N2a assay in 40, 41, 50, and 70% of H. plumierii, O. chrysurus, B. vetula, and E. guttatus, respectively. Of the fish collected, 4% had Caribbean ciguatoxin levels exceeding the US Food and Drug Administration guidance of 0.1 ng Caribbean ciguatoxin‐1 eq/g fish. These findings concurred with spatial ciguatera fish poisoning prevalence information provided by local fishers in the US Virgin Islands and demonstrate how partnerships between researchers and fishers can aid the improvement of science‐based ciguatera fish poisoning management. Environ Toxicol Chem 2018;39:1852–1863. Published 2018 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. [ABSTRACT FROM AUTHOR]

SUMMARY Species of the marine benthic dinoflagellate genus Gambierdiscus are the principal cause of Ciguatera fish poisoning. This genus has been recorded from tropical to temperate oceans, although Gambierdiscus species have rarely been found in Chinese waters. Our work revealed the morphological and genetic characteristics of three potentially toxic Gambierdiscus species observed in the temperate to subtropical waters of China. The fine thecal morphology was determined based on light microscopy and scanning electron microscopy analyses, and these species were also characterized by sequencing the D1-D3 and D8-D10 regions of the LSU r DNA. The morphological and genetic data indicated that these three Gambierdiscus species were G. pacificus, G. australes and G. caribaeus. This work provides the first report of these species in Chinese waters, which increases the known species distribution of this genus. [ABSTRACT FROM AUTHOR]

A single cell of the dinoflagellate genus Fukuyoa was isolated from the island of Formentera (Balearic Islands, west Mediterranean Sea), cultured, and characterized by morphological and molecular methods and toxin analyses. This is the first report of the Gambierdiscus lineage (genera Fukuyoa and Gambierdiscus) from the western Mediterranean Sea, which is cooler than its eastern basin. Molecular analyses revealed that the Mediterranean strain belongs to F. paulensis and that it bears LSU rDNA sequences identical to New Zealand, Australian, and Brazilian strains. It also shared an identical sequence of the more variable ITS-rDNA with the Brazilian strain. Toxin analyses showed the presence of maitotoxin, 54-deoxyCTX1 B, and gambieric acid A. This is the first observation of the two latter compounds in a Fukuyoa strain. Therefore, both Gambierdiscus and Fukuyoa should be considered when as contributing to ciguatera fish poisoning. Different strains of Fukuyoa form a complex of morphologically cryptic lineages where F paulensis stands as the most distantly related nominal species. The comparison of the ITS2 secondary structures revealed the absence of CBCs among strains. The study of the morphological and molecular traits depicted an unresolved taxonomic scenario impacted by the low strains sampling. [ABSTRACT FROM AUTHOR]

Cold hypersensitivity is evident in a range of neuropathies and can evoke sensations of paradoxical burning cold pain. Ciguatoxin poisoning is known to induce a pain syndrome caused by consumption of contaminated tropical fish that can persist for months and include pruritus and cold allodynia; at present no suitable treatment is available. This study examined, for the first time, the neural substrates and molecular components of Pacific ciguatoxin-2-induced cold hypersensitivity. Electrophysiological recordings of dorsal horn lamina V/VI wide dynamic range neurones were made in non-sentient rats. Subcutaneous injection of 10 nM cigua-toxin-2 into the receptive field increased neuronal responses to innocuous and noxious cooling. In addition, neuronal responses to low-threshold but not noxious punctate mechanical stimuli were also elevated. The resultant cold hypersensitivity was not reversed by 6-({2-[2-fluoro-6-(trifluoromethyl)phenoxy]-2-methylpropyl}carbamoyl)pyridine-3-carboxylic acid, an antagonist of transient receptor potential melastatin 8 (TRPM8). Both mechanical and cold hypersensitivity were completely prevented by co-injection with the Nav1.8 antagonist A803467, whereas the transient receptor potential ankyrin 1 (TRPA1) antagonist A967079 only prevented hypersensitivity to innocuous cooling and partially prevented hypersensitivity to noxious cooling. In naive rats, neither innocuous nor noxious cold-evoked neuronal responses were inhibited by antagonists of Nav1.8, TRPA1 or TRPM8 alone. Cigua-toxins may confer cold sensitivity to a subpopulation of cold-insensitive Nav1.8/TRPA1-positive primary afferents, which could underlie the cold allodynia reported in ciguatera. These data expand the understanding of central spinal cold sensitivity under normal conditions and the role of these ion channels in this translational rat model of ciguatoxin-induced hypersensitivity. [ABSTRACT FROM AUTHOR]

The benthic dinoflagellates in the genus Gambierdiscus produce toxins that bioaccumulate in tropical and sub-tropical fish causing ciguatera fish poisoning ( CFP). Other co-occurring genera such as Coolia have also been implicated in causing CFP. Little is known about the diversity of the two genera Gambierdiscus and Coolia along the Thai coasts. The results of morphological analyses based on observation under light microscopy and scanning electron microcopy showed that strains of Gambierdiscus from Thailand displayed the typical Gambierdiscus plate formula: Po, 4′, 0a, 6″, 6c,?s, 5′′′, 0p and 2′′′′. Morphological examination of Thai Gambierdiscus enabled it to be identified as Gambierdiscus caribaeus: round and anterior-posteriorly compressed cell shape, broad 2′′′′ plate, rectangular 2′ plate, and symmetrical 3″ plate. The phylogenetic analyses based on the large subunit ( LSU) rDNA D8/ D10 sequences of Gambierdiscus from Thailand confirmed the morphological identification. The thecal plate formula for all of the Coolia isolates from Thailand was Po, 4′, 0a, 6″,?c,?s, 5′′′, 0p and 2′′′′. Most, but not all, of these isolates could be identified morphologically as Coolia malayensis. An LSU rDNA D1/ D2 phylogenetic analysis confirmed identity of C. malayensis isolates identified morphologically. The remaining unidentified isolates fell in the C. tropicalis clade. [ABSTRACT FROM AUTHOR]

Ciguatoxins, the principal causative agents of ciguatera seafood poisoning, are extremely large polycyclic ethers. We report herein a reliable route for constructing the left wing of CTX1B, which possesses the acid/base/oxidant-sensitive bisallylic ether moiety, by a 6- exo radical cyclization/ring-closing metathesis strategy. This new route enabled us to achieve the second-generation total synthesis of CTX1B and the first synthesis of 54-deoxyCTX1B. [ABSTRACT FROM AUTHOR]

Ciguatera poisoning is a toxinological syndrome from ingestion of seafood contaminated by dinoflagellate toxins which has serious social and economic consequences from the Indo-Pacific to the Caribbean. These polyannealed ethereal-ring toxins, which comprise ciguatoxins, maitotoxin, and gambierol, are known to affect ion channels. Reported here are the first indications at molecular level as to the mode of interaction of these toxins with ion channels. The study concerns gambierol, an eight-ring ladder polyether which is known to affect TRPV1-type of thermal and pain sensation channels, as well as to inhibit voltage-gated currents in K+ channels of mouse taste cells. Automated docking of gambierol on a homology model of the voltage-gated Kv1.5 potassium ion channel in implicit solvent is followed by molecular dynamics (MD) simulation of the complex in a POPC membrane solvated with water. It is found that gambierol binds to the internal helices of the channel, unequally to the different subunits of the tetramer. Such unequal binding is a novel observation that should stimulate and aid developing a much demanded medical treatment of ciguatera poisoning. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Gambierdiscus is a genus of benthic dinoflagellates found worldwide. Some species produce neurotoxins (maitotoxins and ciguatoxins) that bioaccumulate and cause ciguatera fish poisoning ( CFP), a potentially fatal food-borne illness that is common worldwide in tropical regions. The investigation of toxigenic species of Gambierdiscus in CFP endemic regions in Australia is necessary as a first step to determine which species of Gambierdiscus are related to CFP cases occurring in this region. In this study, we characterized five strains of Gambierdiscus collected from Heron Island, Australia, a region in which ciguatera is endemic. Clonal cultures were assessed using (i) light microscopy; (ii) scanning electron microscopy; (iii) DNA sequencing based on the nuclear encoded ribosomal 18S and D8-D10 28S regions; (iv) toxicity via mouse bioassay; and (v) toxin profile as determined by Liquid Chromatography-Mass Spectrometry. Both the morphological and phylogenetic data indicated that these strains represent a new species of Gambierdiscus, G. lapillus sp. nov. (plate formula Po, 3′, 0a, 7″, 6c, 7-8s, 5‴, 0p, 2″″ and distinctive by size and hatchet-shaped 2′ plate). Culture extracts were found to be toxic using the mouse bioassay. Using chemical analysis, it was determined that they did not contain maitotoxin ( MTX1) or known algal-derived ciguatoxin analogs ( CTX3B, 3C, CTX4A, 4B), but that they contained putative MTX3, and likely other unknown compounds. [ABSTRACT FROM AUTHOR]

ON THE COVER Scanning electron micrograph of Gambierdiscus lapillus sp. nov., on a Tescan VEGA3 microscope. The picture shows the heavy thecal ornamentation for which the species is named (Latin, lapillus = little gem). The new species may hold the key in identifying the causative agent of ciguatera fish poisoning in Australia. SEM image: Mona Hoppenrath [Vol. 53, No. 2, pp. 283-297] [ABSTRACT FROM AUTHOR]