Smith, KF, Biessy, L, Argyle, PA, Trnski, T, Halafihi, T & Rhodes, LL 2017, 'Molecular identification of Gambierdiscus and Fukuyoa (Dinophyceae) from environmental samples', Marine Drugs, vol. 15, no. 8.View/Download from: Publisher's site
© 2017 by the authors. Licensee MDPI. Ciguatera Fish Poisoning (CFP) is increasing across the Pacific and the distribution of the causative dinoflagellates appears to be expanding. Subtle differences in thecal plate morphology are used to distinguish dinoflagellate species, which are difficult to determine using light microscopy. For these reasons we sought to develop a Quantitative PCR assay that would detect all species from both Gambierdiscus and Fukuyoa genera in order to rapidly screen environmental samples for potentially toxic species. Additionally, a specific assay for F. paulensis was developed as this species is of concern in New Zealand coastal waters. Using the assays we analyzed 31 samples from three locations around New Zealand and the Kingdom of Tonga. Fourteen samples in total were positive for Gambierdiscus/Fukuyoa and two samples were also positive using the F. paulensis assay. Samples from the Kermadec Islands were further characterized using high-throughput sequencing metabarcoding. The majority of reads corresponded to Gambierdiscus species with three species identified at all sites (G. australes, G. honu and G. polynesiensis). This is the first confirmed identification of G. polynesiensis, a known ciguatoxin producer, in New Zealand waters. Other known toxin-producing genera were also detected, included Alexandrium, Amphidinium, Azadinium, Dinophysis, Ostreopsis, and Prorocentrum.
Argyle, PA, Harwood, DT, Rhodes, LL, Champeau, O & Tremblay, LA 2016, 'Toxicity assessment of New Zealand and Pacific dinoflagellates Ostreopsis and Gambierdiscus (Dinophyceae) extracts using bioassays', New Zealand Journal of Marine and Freshwater Research, vol. 50, no. 3, pp. 444-456.View/Download from: Publisher's site
© 2016 The Royal Society of New Zealand. The dinoflagellate genus Ostreopsis produces palytoxin-like compounds (PLTXs) and the genus Gambierdiscus produces ciguatoxins (CTXs) and maitotoxin (MTX). Human illness has been recorded following the consumption of CTX-contaminated finfish. Their effects on the flora and fauna in the environment are largely unexplored. Toxin profiles of extracts of Ostreopsis and Gambierdiscus isolates from the Pacific region were characterised using liquid chromatography tandem mass spectrometry. Sea urchin (Evechinus chloriticus) fertilisation was unaffected by any algal extracts, but extracts containing maitotoxin-3 (MTX-3, but not MTX or CTXs), or with high concentrations of PLTXs, were toxic to urchin larval development. Gambierdiscus extracts containing CTXs elicited toxic responses in zebrafish (Danio rerio) embryo toxicity assays; extracts containing only MTX-3 elicited a limited response. Ostreopsis extracts containing PLTXs caused no response. The results demonstrate potential impacts of toxic dinoflagellates on larval organisms and the potential of embryonic assays as toxicity screening tools.
Rhodes, L, Harwood, T, Smith, K, Argyle, P & Munday, R 2016, 'Corrigendum to ‘Production of ciguatoxin and maitotoxin by strains of Gambierdiscus australes, G. pacificus and G. polynesiensis (Dinophyceae) isolated from Rarotonga, Cook Islands’ [Harmful Algae 39 (2014) 185–190] (S1568988314001449) (10.1016/j.hal.2014.07.018))', Harmful Algae, vol. 55, p. 295.View/Download from: Publisher's site
© 2016 Elsevier B.V. The authors regret that there are some errors in the above paper. Below is a correction to the Results section (sub-heading Toxin production) and the correct version of Table 2: Toxin production: G. polynesiensis CAWD212 produced CTX and putative MTX-3 and four isolates of G. pacificus (CAWD213, NLD-10, NLD-11 and NLD-14) and G. australes CAWD216 produced putative MTX-3 only (Table 2). The authors would like to apologise for any inconvenience caused.
Rhodes, L, Harwood, T, Smith, K, Argyle, P & Munday, R 2014, 'Production of ciguatoxin and maitotoxin by strains of Gambierdiscus australes, G. pacificus and G. polynesiensis (Dinophyceae) isolated from Rarotonga, Cook Islands', Harmful Algae, vol. 39, pp. 185-190.View/Download from: Publisher's site
© 2014 Elsevier B.V. The isolation and culturing of toxic Gambierdiscus species is desirable for obtaining reliable sources of toxins responsible for Ciguatera Fish Poisoning (CFP) in order to provide reference materials and purified standards for chemical analyses and bioassays. Gambierdiscus polynesiensis CAWD212, G. pacificus CAWD213 and G. australes CAWD149 and 216 have been isolated from samples of sea water from the Cook Islands. G. polynesiensis produced ciguatoxins (CTX; 18.2pg per cell) and G. australes CAWD149 produced maitotoxin (MTX; 8.3pg per cell) and in both extracts putative MTX-3 was detected. G. pacificus also produced putative MTX-3. The toxicities of extracts of G. polynesiensis and G. pacificus were similar by i.p. injection (LD50s of 1.0mg/kg and 0.8mg/kg respectively), but when administered by gavage, the MTX-3 analogue producing G. pacificus (LD50 251mg/kg) was 30-times less toxic than the CTX-producing G. polynesiensis (LD50 7.9mg/kg). Consumption of fish contaminated by CFP has caused illness and even death in the Cook Islands and throughout the Pacific region and is now considered a globally neglected disease. Large-scale cultures of these organisms are now available, and isolation of the toxins they produce is in progress.