1 National Institute of Health Sciences (NIHS, Japan) – 1-18-1 Kamiyoga, Setagaya, Tokyo 158-8501, Japan
2 Department of Food and Life Science, Azabu University – 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan
3 Graduate School of Science, University of the Ryukyus – 1 Senbaru, Nishihara, Okinawa 903-0213, Japan
4 Bonins a Pirates – Kiyose, Ogasawara, Tokyo 100-2101, Japan
5 Faculty of Science, University of the Ryukyus – 1 Senbaru, Nishihara, Okinawa 903-0213, Japan
6Tama Laboratory, Japan Food Research Laboratories – 6-11-10 Nagayama, Tama, Tokyo 206-0025, Japan
We analyzed ciguatoxins (CTXs) in fish specimens ofVariola louti collected off the Japanese Waters. Standard mix solution of CTXs used for LC-MS/MS was prepared from natural re- sources such as toxic fish specimens and dinoflagellate Gambierdiscus toxicus. And also, the reference materials, Ciguatoxin-1B and Ciguatoxin-3C provided by Japan Food Research Lab- oratory were used for quantitative analysis.
CTX1B congeners including CTX1B, 54-epi-52-deoxy-CTX1B and 52-deoxyCTX1B were de- tected from most of the specimens collected off Okinawa and Amami where recognized as CFP endemic area. The levels of CTX congeners were less than LOD in the all specimens obtained from Ogasawara (Bonin). According to interview to residents of the Chichijima a largest island in the Ogasawara, there has been no experience of CFP within the island.
LC-MS/MS analyses were also carried out on the samples prepared from several parts of the head and body. Within these samples, the extraocular muscles contained CTXS in two to three times higher concentrations than the other parts of muscles. The profiles of the CTX1B congeners were identical within the individual specimens.
∗Speaker
†Corresponding author: n-oshiro@nihs.go.jp
Managing the risk of Ciguatera Fish Poisoning in temperate Australia
Michaela E. Larsson ∗† 1, Martina Doblin 1
1 University of Technology Sydney (UTS) – P.O. Box 123, Broadway, New South Wales, Australia, 2007, Australia
Ciguatera Fish Poisoning (CFP) is a human illness caused by the consumption of seafood contaminated with ciguatoxins. CFP has been a problem in tropical Australia for some time, however more recently, there were several outbreaks linked to fish caught in cooler waters, prompting renewed concern. Ciguatoxins are produced by some species from the epibenthic microalgal genusGambierdiscus. Species from this genus are typically found in tropical environ- ments though in recent years, populations have been documented in more temperate locations.
In this study, we used a taxonomic, toxicological and ecological approach to assess the poten- tial of Gambierdiscus to extend its range in eastern Australia and evaluate what this means for managing the risk of human exposure to CFP in more temperate waters. Four species of Gambierdiscus (G. cf. pacificus, G. cf. silvae, G. carpenteri and G. lapillus) were identified from the tropical Great Barrier Reef region of Australia and onlyG. carpenteri was found at a temperate location. Interestingly, toxin profiling indicated differences between the tropical and temperate populations. Fitness curves across environmental gradients of temperature, salinity and irradiance suggest the distribution ofGambierdiscus is not limited by these abiotic factors, so the current and future species distribution is likely to be determined by other factors. Rafting on detached macrophyte fragments, transported south with the East Australian Current was found to be the likely natural long distance dispersal mechanism aiding extension of the distri- bution into more temperate locations, and successful colonisation was found to only require a single pulse of very few cells.
The risk of ciguatera fish poisoning to New Zealand and its territorial waters and a
molecular approach to monitoring
Lesley Rhodes ∗ 1, Kirsty Smith 1, Tim Harwood 1, Sam Murray 1, Rex Munday 2
1 Cawthron Institute (Cawthron) – 98 Halifax St East, Private Bag 2, Nelson, New Zealand
2 AgResearch (AgResearch) – Ruakura Research Centre, 10 Bisley Road, Private Bag 3240, Hamilton, New Zealand
Ciguatera fish poisoning (CFP) in humans is caused by the consumption of fish contaminated with ciguatoxins (CTXs), which are produced by species of the epiphytic dinoflagellate genus Gambierdiscus. With rising sea temperatures, it is expected thatGambierdiscus, which is preva- lent in the tropical south west Pacific region, will become established in mainland New Zealand.
In recent yearsGambierdiscus and CTX-contaminated fish have also been expanding into other more temperate waters (for example, New South Wales, Australia), which adds another factor to the CFP risk. Both traditional methods (microscopy and cell counts) and molecular techniques (qPCR, high-throughput sequencing) are being used to determine the potential risk of CFP occurring in New Zealand. CTXs and maitotoxins produced by Gambierdiscus isolates are be- ing characterised by chemical tests (LC-MS/MS) under development at the Cawthron Institute.
The toxicity ofGambierdiscus extracts is also being determined and preliminary results suggest that currently uncharacterised toxin compounds are being produced by some Gambierdiscus species.
∗Speaker
Towards a transcriptomic signature of long-term CTX exposure in naso
brevirostris
Gregory Nuel ∗ 1, Franck Letourneur 2, Jean-Philippe Jais 3, Fr´ ed´ eric Tores 3, Marie-Yasmine Dechraoui Bottein 4, Rachel Clausing 4, Andrea