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Understanding the toxicity and production rates of the various secondary metabolites produced by Gambierdiscus and cohabitating benthic dinoflagellates is essential to unravelling the complexities associated with ciguatera poisoning. In the present study, a sulphated cyclic polyether, gambierone, was purified from Gambierdiscus cheloniae CAWD232 and its acute toxicity was determined using intraperitoneal injection into mice. It was shown to be of low toxicity with an LD50 of 2.4 mg/kg, 9600 times less toxic than the commonly implicated Pacific ciguatoxin-1B, indicating it is unlikely to play a role in ciguatera poisoning. In addition, the production of gambierone and 44-methylgambierone was assessed from 20 isolates of ten Gambierdiscus, two Coolia and two Fukuyoa species using quantitative liquid chromatography–tandem mass spectrometry. Gambierone was produced by seven Gambierdiscus species, ranging from 1 to 87 pg/cell, and one species from each of the genera Coolia and Fukuyoa, ranging from 2 to 17 pg/cell. The production of 44-methylgambierone ranged from 5 to 270 pg/cell and was ubiquitous to all Gambierdiscus species tested, as well as both species of Coolia and Fukuyoa. The relative production ratio of these two secondary metabolites revealed that only two species produced more gambierone, G. carpenteri CAWD237 and G. cheloniae CAWD232. This represents the first report of gambierone acute toxicity and production by these cohabitating benthic dinoflagellate species. While these results demonstrate that gambierones are unlikely to pose a risk to human health, further research is required to understand if they bioaccumulate in the marine food web.
J. Murray; Sarah Finch; Jonathan Puddick; Lesley Rhodes; D. Harwood; Roel van Ginkel; Michèle Prinsep. Acute Toxicity of Gambierone and Quantitative Analysis of Gambierones Produced by Cohabitating Benthic Dinoflagellates. Toxins 2021, 13, 333 .
AMA StyleJ. Murray, Sarah Finch, Jonathan Puddick, Lesley Rhodes, D. Harwood, Roel van Ginkel, Michèle Prinsep. Acute Toxicity of Gambierone and Quantitative Analysis of Gambierones Produced by Cohabitating Benthic Dinoflagellates. Toxins. 2021; 13 (5):333.
Chicago/Turabian StyleJ. Murray; Sarah Finch; Jonathan Puddick; Lesley Rhodes; D. Harwood; Roel van Ginkel; Michèle Prinsep. 2021. "Acute Toxicity of Gambierone and Quantitative Analysis of Gambierones Produced by Cohabitating Benthic Dinoflagellates." Toxins 13, no. 5: 333.
The cyanobacterium Microcoleus autumnalis grows as thick benthic mats in rivers and is becoming increasingly prevalent around the world. M. autumnalis can produce high concentrations of anatoxins and ingestion of benthic mats has led to multiple dog deaths over the past two decades. M. autumnalis produces a suite of different anatoxin congeners including anatoxin-a (ATX), dihydroanatoxin-a, (dhATX), homoanatoxin-a and dihydrohomoanatoxin-a. Benthic mat samples often contain high levels of dhATX, but there is little toxicology information on this congener. In the present study, natural versions of dhATX and ATX were purified from cyanobacteria to determine the acute toxicity by different routes of administration using mice. Nuclear magnetic resonance spectroscopy was used to confirm the putative structure of dhATX. By intraperitoneal (ip) injection, the median lethal dose (LD50) for dhATX was 0.73 mg/kg, indicating a reduced toxicity compared to ATX (LD50 of 0.23 mg/kg). However, by oral administration (both gavage and feeding), dhATX was more toxic than ATX (gavage LD50 of 2.5 mg/kg for dhATX and 10.6 mg/kg for ATX; feeding LD50 of 8 mg/kg for dhATX and 25 mg/kg for ATX). The relative nicotinic acetylcholine receptor (nAChR)-binding affinities of ATX and dhATX were determined using the Torpedo electroplaque assay which showed consistency with the relative toxicity determined by ip injection. This work highlights that toxicity studies based solely on ip injection may not yield LD50 values that are relevant to those derived via oral administration, and hence, do not provide a good estimate of the risk posed to human and animal health in situations where oral ingestion is the likely route of exposure. The high acute oral toxicity of dhATX, and its abundance in M. autumnalis proliferations, demonstrates that it is an important environmental contaminant that warrants further investigation.
Jonathan Puddick; Roel van Ginkel; Carrie D. Page; J. Sam Murray; Hannah E. Greenhough; Joel Bowater; Andrew I. Selwood; Susanna A. Wood; Michèle R. Prinsep; Penelope Truman; Rex Munday; Sarah C. Finch. Acute toxicity of dihydroanatoxin-a from Microcoleus autumnalis in comparison to anatoxin-a. Chemosphere 2020, 263, 127937 .
AMA StyleJonathan Puddick, Roel van Ginkel, Carrie D. Page, J. Sam Murray, Hannah E. Greenhough, Joel Bowater, Andrew I. Selwood, Susanna A. Wood, Michèle R. Prinsep, Penelope Truman, Rex Munday, Sarah C. Finch. Acute toxicity of dihydroanatoxin-a from Microcoleus autumnalis in comparison to anatoxin-a. Chemosphere. 2020; 263 ():127937.
Chicago/Turabian StyleJonathan Puddick; Roel van Ginkel; Carrie D. Page; J. Sam Murray; Hannah E. Greenhough; Joel Bowater; Andrew I. Selwood; Susanna A. Wood; Michèle R. Prinsep; Penelope Truman; Rex Munday; Sarah C. Finch. 2020. "Acute toxicity of dihydroanatoxin-a from Microcoleus autumnalis in comparison to anatoxin-a." Chemosphere 263, no. : 127937.
Ciguatera fish poisoning (CFP) is prevalent around the tropical and sub-tropical latitudes of the world and impacts many Pacific island communities intrinsically linked to the reef system for sustenance and trade. While the genus Gambierdiscus has been linked with CFP, it is commonly found on tropical reef systems in microalgal assemblages with other genera of toxin-producing, epiphytic and/or benthic dinoflagellates – Amphidinium, Coolia, Fukuyoa, Ostreopsis and Prorocentrum. Identifying a biomarker compound that can be used for the early detection of Gambierdiscus blooms, specifically in a mixed microalgal community, is paramount in enabling the development of management and mitigation strategies. Following on from the recent structural elucidation of 44-methylgambierone, its potential to contribute to CFP intoxication events and applicability as a biomarker compound for Gambierdiscus spp. was investigated. The acute toxicity of this secondary metabolite was determined by intraperitoneal injection using mice, which showed it to be of low toxicity, with an LD50 between 20 and 38 mg kg−1. The production of 44-methylgambierone by 252 marine microalgal isolates consisting of 90 species from 32 genera across seven classes, was assessed by liquid chromatography-tandem mass spectrometry. It was discovered that the production of this secondary metabolite was ubiquitous to the eight Gambierdiscus species tested, however not all isolates of G. carpenteri, and some species/isolates of Coolia and Fukuyoa.
J. Sam Murray; Tomohiro Nishimura; Sarah C. Finch; Lesley L. Rhodes; Jonathan Puddick; D. Tim Harwood; Michaela E. Larsson; Martina A. Doblin; Priscilla Leung; Meng Yan; Frode Rise; Alistair L. Wilkins; Michèle R. Prinsep. The role of 44-methylgambierone in ciguatera fish poisoning: Acute toxicity, production by marine microalgae and its potential as a biomarker for Gambierdiscus spp. Harmful Algae 2020, 97, 101853 .
AMA StyleJ. Sam Murray, Tomohiro Nishimura, Sarah C. Finch, Lesley L. Rhodes, Jonathan Puddick, D. Tim Harwood, Michaela E. Larsson, Martina A. Doblin, Priscilla Leung, Meng Yan, Frode Rise, Alistair L. Wilkins, Michèle R. Prinsep. The role of 44-methylgambierone in ciguatera fish poisoning: Acute toxicity, production by marine microalgae and its potential as a biomarker for Gambierdiscus spp. Harmful Algae. 2020; 97 ():101853.
Chicago/Turabian StyleJ. Sam Murray; Tomohiro Nishimura; Sarah C. Finch; Lesley L. Rhodes; Jonathan Puddick; D. Tim Harwood; Michaela E. Larsson; Martina A. Doblin; Priscilla Leung; Meng Yan; Frode Rise; Alistair L. Wilkins; Michèle R. Prinsep. 2020. "The role of 44-methylgambierone in ciguatera fish poisoning: Acute toxicity, production by marine microalgae and its potential as a biomarker for Gambierdiscus spp." Harmful Algae 97, no. : 101853.
Gambierdiscus and Fukuyoa species have been identified in Aotearoa/New Zealand’s coastal waters and G. polynesiensis, a known producer of ciguatoxins, has been isolated from Rangitāhua/Kermadec Islands (a New Zealand territory). The warming of the Tasman Sea and the waters around New Zealand’s northern subtropical coastline heighten the risk of Gambierdiscus proliferating in New Zealand. If this occurs, the risk of ciguatera fish poisoning due to consumption of locally caught fish will increase. Research, including the development and testing of sampling methods, molecular assays, and chemical and toxicity tests, will continue. Reliable monitoring strategies are important to manage and mitigate the risk posed by this emerging threat. The research approaches that have been made, many of which will continue, are summarised in this review.
Lesley L. Rhodes; Kirsty F. Smith; J. Sam Murray; Tomohiro Nishimura; Sarah C. Finch. Ciguatera Fish Poisoning: The Risk from an Aotearoa/New Zealand Perspective. Toxins 2020, 12, 50 .
AMA StyleLesley L. Rhodes, Kirsty F. Smith, J. Sam Murray, Tomohiro Nishimura, Sarah C. Finch. Ciguatera Fish Poisoning: The Risk from an Aotearoa/New Zealand Perspective. Toxins. 2020; 12 (1):50.
Chicago/Turabian StyleLesley L. Rhodes; Kirsty F. Smith; J. Sam Murray; Tomohiro Nishimura; Sarah C. Finch. 2020. "Ciguatera Fish Poisoning: The Risk from an Aotearoa/New Zealand Perspective." Toxins 12, no. 1: 50.
Approximately 70 species of Prorocentrum are known, of which around 30 species are associated with benthic habitats. Some produce okadaic acid (OA), dinophysistoxin (DTX) and their derivatives, which are involved in diarrhetic shellfish poisoning. In this study, we isolated and characterized Prorocentrum concavum and P. malayense from Broome in north Western Australia using light and scanning electron microscopy as well as molecular sequences of large subunit regions of ribosomal DNA, marking the first record of these species from Australian waters. The morphology of the motile cells of P. malayense was similar to P. concavum in the light microscopy, but differed by the smooth thecal surface, the pore pattern and the production of mucous stalk-like structures and a hyaline sheath around the non-motile cells. P. malayense could also be differentiated from other closely related species, P. leve and P. foraminosum, despite the similarity in thecal surface and pore pattern, by its platelet formula and morphologies. We tested the production of OA and DTXs from both species, but found that they did not produce detectable levels of these toxins in the given culturing conditions. This study aids in establishing more effective monitoring of potential harmful algal taxa in Australian waters for aquaculture and recreational purposes.
Arjun Verma; Aniuska Kazandjian; Chowdhury Sarowar; D. Tim Harwood; J. Sam Murray; Insa Pargmann; Mona Hoppenrath; Shauna A. Murray. Morphology and Phylogenetics of Benthic Prorocentrum Species (Dinophyceae) from Tropical Northwestern Australia. Toxins 2019, 11, 571 .
AMA StyleArjun Verma, Aniuska Kazandjian, Chowdhury Sarowar, D. Tim Harwood, J. Sam Murray, Insa Pargmann, Mona Hoppenrath, Shauna A. Murray. Morphology and Phylogenetics of Benthic Prorocentrum Species (Dinophyceae) from Tropical Northwestern Australia. Toxins. 2019; 11 (10):571.
Chicago/Turabian StyleArjun Verma; Aniuska Kazandjian; Chowdhury Sarowar; D. Tim Harwood; J. Sam Murray; Insa Pargmann; Mona Hoppenrath; Shauna A. Murray. 2019. "Morphology and Phylogenetics of Benthic Prorocentrum Species (Dinophyceae) from Tropical Northwestern Australia." Toxins 11, no. 10: 571.
Species in the genus Gambierdiscus produce ciguatoxins (CTXs) and/or maitotoxins (MTXs), which may cause ciguatera fish poisoning (CFP) in humans if contaminated fish are consumed. Species of Gambierdiscus have previously been isolated from macroalgae at Rangitahua (Raoul Island and North Meyer Islands, northern Kermadec Islands), and the opportunity was taken to sample for Gambierdiscus at the more southerly Macauley Island during an expedition in 2016. Gambierdiscus cells were isolated, cultured, and DNA extracted and sequenced to determine the species present. Bulk cultures were tested for CTXs and MTXs by liquid chromatography-mass spectrometry (LC-MS/MS). The species isolated were G. australes, which produced MTX-1 (ranging from 3 to 36 pg/cell), and G. polynesiensis, which produced neither MTX-1 nor, unusually, any known CTXs. Isolates of both species produced putative MTX-3. The risk of fish, particularly herbivorous fish, causing CFP in the Zealandia and Kermadec Islands region is real, although in mainland New Zealand the risk is currently low. Both Gambierdiscus and Fukuyoa have been recorded in the sub-tropical northern region of New Zealand, and so the risk may increase with warming seas and shift in the distribution of Gambierdiscus species.
Lesley L. Rhodes; Kirsty F. Smith; Sam Murray; D. Tim Harwood; Tom Trnski; Rex Munday. The Epiphytic Genus Gambierdiscus (Dinophyceae) in the Kermadec Islands and Zealandia Regions of the Southwestern Pacific and the Associated Risk of Ciguatera Fish Poisoning. Marine Drugs 2017, 15, 219 .
AMA StyleLesley L. Rhodes, Kirsty F. Smith, Sam Murray, D. Tim Harwood, Tom Trnski, Rex Munday. The Epiphytic Genus Gambierdiscus (Dinophyceae) in the Kermadec Islands and Zealandia Regions of the Southwestern Pacific and the Associated Risk of Ciguatera Fish Poisoning. Marine Drugs. 2017; 15 (7):219.
Chicago/Turabian StyleLesley L. Rhodes; Kirsty F. Smith; Sam Murray; D. Tim Harwood; Tom Trnski; Rex Munday. 2017. "The Epiphytic Genus Gambierdiscus (Dinophyceae) in the Kermadec Islands and Zealandia Regions of the Southwestern Pacific and the Associated Risk of Ciguatera Fish Poisoning." Marine Drugs 15, no. 7: 219.
Ciguatoxins (CTXs), and possibly maitotoxins (MTXs), are responsible for Ciguatera Fish Poisoning, an important health problem for consumers of reef fish (such as inhabitants of islands in the South Pacific Ocean). The habitational range of the Gambierdiscus species is expanding, and new species are being discovered. In order to provide information on the potential health risk of the Gambierdiscus species, and one Fukuyoa species (found in the Cook Islands, the Kermadec Islands, mainland New Zealand, and New South Wales, Australia), 17 microalgae isolates were collected from these areas. Unialgal cultures were grown and extracts of the culture isolates were analysed for CTXs and MTXs by liquid chromatography tandem mass spectrometry (LC-MS/MS), and their toxicity to mice was determined by intraperitoneal and oral administration. An isolate of G. carpenteri contained neither CTXs nor MTXs, while 15 other isolates (including G. australes, G. cheloniae, G. pacificus, G. honu, and F. paulensis) contained only MTX-1 and/or MTX-3. An isolate of G. polynesiensis contained both CTXs and MTX-3. All the extracts were toxic to mice by intraperitoneal injection, but those containing only MTX-1 and/or -3 were much less toxic by oral administration. The extract of G. polynesiensis was highly toxic by both routes of administration.
Rex Munday; Sam Murray; Lesley L. Rhodes; Michaela E. Larsson; D. Tim Harwood. Ciguatoxins and Maitotoxins in Extracts of Sixteen Gambierdiscus Isolates and One Fukuyoa Isolate from the South Pacific and Their Toxicity to Mice by Intraperitoneal and Oral Administration. Marine Drugs 2017, 15, 208 .
AMA StyleRex Munday, Sam Murray, Lesley L. Rhodes, Michaela E. Larsson, D. Tim Harwood. Ciguatoxins and Maitotoxins in Extracts of Sixteen Gambierdiscus Isolates and One Fukuyoa Isolate from the South Pacific and Their Toxicity to Mice by Intraperitoneal and Oral Administration. Marine Drugs. 2017; 15 (7):208.
Chicago/Turabian StyleRex Munday; Sam Murray; Lesley L. Rhodes; Michaela E. Larsson; D. Tim Harwood. 2017. "Ciguatoxins and Maitotoxins in Extracts of Sixteen Gambierdiscus Isolates and One Fukuyoa Isolate from the South Pacific and Their Toxicity to Mice by Intraperitoneal and Oral Administration." Marine Drugs 15, no. 7: 208.
Two isolates of a new tropical, epiphytic dinoflagellate species, Gambierdiscus honu sp. nov., were obtained from macroalgae sampled in Rarotonga, Cook Islands, and from North Meyer Island, Kermadec Islands. Gambierdiscus honu sp. nov. had the common Gambierdiscus Kofoidian plate formula: Po, 3', 6″, 6C?, 6 or 7S, 5‴, 1p and 2⁗. The characteristic morphological features of this species were its relatively small short dorsoventral length and width and the shape of individual plates, in particular the combination of the hatchet-shaped 2' and pentagonal 3' plates and the length to width ratio of the antapical 1p plate. The combination of these characteristics plus the smooth thecal surface and equal sized 1⁗ and 2⁗ plates differentiated this species from other Gambierdiscus species. The phylogenetic analyses supported the unique description. Both isolates of G. honu produced the putative maitotoxin (MTX)-3 analogue, but neither produced ciguatoxin (CTX) or MTX. Extracts of G. honu were shown to be highly toxic to mice by intraperitoneal injection (0.2mg/kg), although less toxic by gavage. It is possible that toxins other than putative MTX-3 are produced.
Lesley Rhodes; Kirsty F. Smith; Arjun Verma; Belinda G. Curley; D. Tim Harwood; Sam Murray; Gurjeet S. Kohli; Dorothy Solomona; Teina Rongo; Rex Munday; Shauna A. Murray. A new species of Gambierdiscus (Dinophyceae) from the south-west Pacific: Gambierdiscus honu sp. nov. Harmful Algae 2017, 65, 61 -70.
AMA StyleLesley Rhodes, Kirsty F. Smith, Arjun Verma, Belinda G. Curley, D. Tim Harwood, Sam Murray, Gurjeet S. Kohli, Dorothy Solomona, Teina Rongo, Rex Munday, Shauna A. Murray. A new species of Gambierdiscus (Dinophyceae) from the south-west Pacific: Gambierdiscus honu sp. nov. Harmful Algae. 2017; 65 ():61-70.
Chicago/Turabian StyleLesley Rhodes; Kirsty F. Smith; Arjun Verma; Belinda G. Curley; D. Tim Harwood; Sam Murray; Gurjeet S. Kohli; Dorothy Solomona; Teina Rongo; Rex Munday; Shauna A. Murray. 2017. "A new species of Gambierdiscus (Dinophyceae) from the south-west Pacific: Gambierdiscus honu sp. nov." Harmful Algae 65, no. : 61-70.
An expedition to North Meyer Island, Kermadec Islands, in November 2015, resulted in the isolation of two Gambierdiscus species, G. australes and a previously unknown Gambierdiscus species maintained in the Cawthron Institute Culture Collection of Micro-algae as CAWD242. Identifications were based on morphology and DNA sequence data analysis. Nine isolates of G. australes produced maitotoxin-1 (MTX-1) ranging from present (detectable but below the confidence level) to 36.6 pg per cell. One further isolate did not produce MTX-1, but all G. australes isolates produced putative MTX-3. Isolate CAWD242 was negative for MTX-1 but produced MTX-3. Ostreopsis sp. 3 isolated from samples collected during an earlier expedition in 2013 produced low concentrations of palytoxin (PLTX)-like compounds (0.013 pg per cell), but an isolate of the same species from samples collected in 2015 was non-toxic. Other dinoflagellates isolated and identified were Coolia malayensis, Amphidinium carterae and Prorocentrum hoffmannianum.
Lesley L. Rhodes; Kirsty F. Smith; Arjun Verma; Sam Murray; D. Tim Harwood; Tom Trnski. The dinoflagellate genera Gambierdiscus and Ostreopsis from subtropical Raoul Island and North Meyer Island, Kermadec Islands. New Zealand Journal of Marine and Freshwater Research 2017, 51, 490 -504.
AMA StyleLesley L. Rhodes, Kirsty F. Smith, Arjun Verma, Sam Murray, D. Tim Harwood, Tom Trnski. The dinoflagellate genera Gambierdiscus and Ostreopsis from subtropical Raoul Island and North Meyer Island, Kermadec Islands. New Zealand Journal of Marine and Freshwater Research. 2017; 51 (4):490-504.
Chicago/Turabian StyleLesley L. Rhodes; Kirsty F. Smith; Arjun Verma; Sam Murray; D. Tim Harwood; Tom Trnski. 2017. "The dinoflagellate genera Gambierdiscus and Ostreopsis from subtropical Raoul Island and North Meyer Island, Kermadec Islands." New Zealand Journal of Marine and Freshwater Research 51, no. 4: 490-504.
D. Tim Harwood; Sam Murray; Michael J. Boundy. Sample Preparation Prior to Marine Toxin Analysis. Advances in the Use of Liquid Chromatography Mass Spectrometry (LC-MS) - Instrumentation Developments and Applications 2017, 89 -136.
AMA StyleD. Tim Harwood, Sam Murray, Michael J. Boundy. Sample Preparation Prior to Marine Toxin Analysis. Advances in the Use of Liquid Chromatography Mass Spectrometry (LC-MS) - Instrumentation Developments and Applications. 2017; ():89-136.
Chicago/Turabian StyleD. Tim Harwood; Sam Murray; Michael J. Boundy. 2017. "Sample Preparation Prior to Marine Toxin Analysis." Advances in the Use of Liquid Chromatography Mass Spectrometry (LC-MS) - Instrumentation Developments and Applications , no. : 89-136.