I research the evolution and molecular ecology of marine microbial eukaryotes and their toxins. Marine biotoxins produced by dinoflagellates, a group of marine microalgae, are amongst the most toxic substances yet recorded and can have severe detrimental impacts on a diverse range of organisms and marine ecosystems.
I am an Associate Professor and core member of the Climate Change Cluster (C3), where I lead the Seafood Safety: Marine Algal Biotoxins research program. In our program, we are developing novel genetic tools for the monitoring of biotoxins based on the unique genetic processes of dinoflagellates. We also research the evolution and ecology of biotoxin production by marine microbial eukaryotes, and the evolution and systematics of the producing organisms. I moved to UTS in 2012 to take up an ARC Future Fellowship position, which has enabled my group to focus and develop our research program.
2018: Jenny Edwards Fellowship
2016 Vice Chancellor's Awards for Research Exellence, Research excellence through collaboration award.
2016 NSW Coastal Management Awards Innovation Prize.
2015 Prescott Prize (Phycological Society of America), with M Hoppenrath, N Chomerat and T Horiguchi.
2012 Australian Research Council Future Fellowship
Journal Editorial Boards:
Associate Editor, Journal of Experimental Marine Biology and Ecology (IF=2.0)
Editorial Board, Harmful Algae (IF=4.0)
Editorial Board, European Journal of Protistology (IF=2.4)
Can supervise: YES
Competitive Research Funding Awarded:
Total since 2008: $5.2 million
Australian Research Council: 9 ARC Grants since 2007 (2 Linkage, Equipment and Infrastructure (LIEF); 2 Discovery Projects; 4 Linkage Projects; 1 Future Fellowship). Non-ARC (funding and in-kind support): (1) Fisheries Research and Development Corporation; (2) The Recreational Fisheries Trust; (3) the Australian Academy of Science; (4) Gordon and Betty Moore Foundation; (5) the Australian Biological Resources Study; and (5) Cooperative Research Centre for Food Agility.
International patent application (WO/2012/155202) – Detection of saxitoxin-producing dinoflagellates.
91168 Molecular Ecology, Spring Semester
Hoppenrath, M, Murray, SA, Chomérat, N & Horiguchi, T 2014, Marine benthic dinoflagellates - unveiling their worldwide biodiversity, 1, Senckenberg, Stuttgart.
This publication presents the first summary of our knowledge of benthic dinoflagellate species. Dinoflagellates are important primary producers and symbionts, but, at the same time, also consumers and parasites. Species compositions of benthic habitats are quite distinct from those of planktonic habitats. Less than 10% of the approximately 2000 described extant dinoflagellate species appear to be benthic. They occur in different types of habitats (chapter II) and their morphology, their behavior, and some of their life cycles (chapter VI) seem to be well adapted to the benthic lifestyle. Information on their geographic distribution is still very limited and is compiled herein (chapter V). The study of harmful benthic dinoflagellates started in the late 1970s when it was suspected that a benthic species, later named Gambierdiscus toxicus, was responsible for ciguatera fish poisoning, a type of human poisoning linked to the consumption of certain species of tropical reef fish. As the number of ciguatera fish poisoning incidents increases, and the distribution of toxin producing benthic taxa seems to be expanding, detailed understanding of the species diversity and the ability to accurately identify them is becoming increasingly important (chapter VII). Dinoflagellate classification is currently undergoing changes and far from being settled, as new species and genera are discovered and systematic entities are rearranged. Many benthic dinoflagellate genera have unusual morphologies and appear to be only remotely related to known planktonic taxa, so that molecular phylogenetic analyses frequently show little statistical support for any relationship (chapter IV). Benthic species display unique thecal plate arrangements compared to planktonic species, e.g. Adenoides, Amphidiniella, Cabra, Planodinium, Sabulodinium, Rhinodinium (chapter III). Therefore, no classification on higher rank levels (e.g. family, order) was used throughout this book. Genera (and species within...
Hallegraef, GM, Bolch, CJ, Hill, DR, Jameson, I, LeRoi, J, McMinn, A, Murray, SA, de Salas, F & Saunders, K 2010, Algae of Australia: Phytoplankton of temperate coastal waters, 1, CSIRO Publishing, Canberra.
Murray, SA 2009, Diversity and phylogenetics of sand-dwelling dinoflagellates, 1, VDM Verlag, Germany.
Ajani, PA, Larsson, ME, Woodcock, S, Rubio, A, Farrell, H, Brett, S & Murray, SA 2020, 'Fifteen years of Pseudo-nitzschia in an Australian estuary, including the first potentially toxic P. delicatissima bloom in the southern hemisphere', Estuarine, Coastal and Shelf Science, vol. 236, pp. 106651-106651.View/Download from: Publisher's site
Barua, A, Ajani, PA, Ruvindy, R, Farrell, H, Zammit, A, Brett, S, Hill, D, Sarowar, C, Hoppenrath, M & Murray, SA 2020, 'First Detection of Paralytic Shellfish Toxins fromAlexandrium pacificumabove the Regulatory Limit in Blue Mussels (Mytilus galloprovincialis) in New South Wales, Australia', MICROORGANISMS, vol. 8, no. 6.View/Download from: Publisher's site
Kim, JH, Ajani, P, Murray, SA, Kim, J-H, Lim, HC, Teng, ST, Lim, PT, Han, M-S & Park, BS 2020, 'Sexual reproduction and genetic polymorphism within the cosmopolitan marine diatom Pseudo-nitzschia pungens', SCIENTIFIC REPORTS, vol. 10, no. 1.View/Download from: Publisher's site
Verma, A, Hughes, DJ, Harwood, DT, Suggett, DJ, Ralph, PJ & Murray, SA 2020, 'Functional significance of phylogeographic structure in a toxic benthic marine microbial eukaryote over a latitudinal gradient along the East Australian Current', Ecology and Evolution.View/Download from: Publisher's site
Ajani, PA, Lim, HC, Verma, A, Lassudrie, M, McBean, K, Doblin, MA & Murray, SA 2020, 'First report of the potentially toxic marine diatomPseudo-nitzschia simulans(Bacillariophyceae) from the East Australian Current', PHYCOLOGICAL RESEARCH, vol. 68, no. 3, pp. 254-259.View/Download from: Publisher's site
Hoppenrath, M, Kretzschmar, AL, Kaufmann, MJ & Murray, SA 2019, 'Morphological and molecular phylogenetic identification and record verification of Gambierdiscus excentricus (Dinophyceae) from Madeira Island (NE Atlantic Ocean)', Marine Biodiversity Records, vol. 12, no. 1.View/Download from: Publisher's site
Kretzschmar, AL, Verma, A, Kohli, GS & Murray, SA 2019, 'Development of a quantitative PCR assay for the detection and enumeration of a potentially ciguatoxin-producing dinoflagellate, Gambierdiscus lapillus (Gonyaulacales, Dinophyceae)'.View/Download from: Publisher's site
Abstract Ciguatera fish poisoning is an illness contracted through the ingestion of seafood containing ciguatoxins. It is prevalent in tropical regions worldwide, including in Australia. Ciguatoxins are produced by some species of Gambierdiscus. Therefore, screening of Gambierdiscus species identification through quantitative PCR (qPCR), along with the determination of species toxicity, can be useful in monitoring potential ciguatera risk in these regions. In Australia, the identity, distribution and abundance of ciguatoxin producing Gambierdiscus spp. is largely unknown. In this study we developed a rapid qPCR assay to quantify the presence and abundance of Gambierdiscus lapillus , a likely ciguatoxic species. We assessed the specificity and efficiency of the qPCR assay. The assay was tested on 25 environmental samples from the Heron Island reef in the southern Great Barrier Reef, a ciguatera endemic region, in triplicate to determine the presence and patchiness of these species across samples from Chnoospora sp., Padina sp. and Sargassum macroalgal hosts. Author's summary Ciguatera fish poisoning is a human disease contracted by ingesting seafood contaminated with a group of neurotoxins. The group of neurotoxins, named ciguatoxins, are synthesised by species of single celled marine algae from the genus Gambierdiscus. Ciguatera fish poisoning occurs worldwide, particularly in tropical nations. Pacific Island nations are disproportionately impacted, and this impact is predicted to increase as the effects of climate change unfold. Few effective monitoring and mitigation strategies exist for ciguatera fish poisoning, and reporting rates of the disease are estimated to be approximately 20% at best. A global ciguatera strategy was developed by a group of researchers coordinated by UNESCO's Intergovernmental Oceanographic Commission to characterise the cause and mode of action of ciguatera fish poisoning, as a matter of urgency. In this study, we designed a qPCR assay...
Murray, SA, Ruvindy, R, Kohli, GS, Anderson, DM & Brosnahan, ML 2019, 'Evaluation of sxtA and rDNA qPCR assays through monitoring of an inshore bloom of Alexandrium catenella Group 1.', Scientific reports, vol. 9, no. 1.View/Download from: Publisher's site
Alexandrium catenella (formerly A. tamarense Group 1, or A. fundyense) is the leading cause of Paralytic Shellfish Poisoning in North and South America, Europe, Africa, Australia and Asia. The quantification of A.catenella via sxtA, a gene involved in Paralytic Shellfish Toxin synthesis, may be a promising approach, but has not been evaluated in situ on blooms of A. catenella, in which cell abundances may vary from not detectable to in the order of 106 cells L-1. In this study, we compared sxtA assay performance to a qPCR assay targeted to a species-specific region of ribosomal DNA (rDNA) and an established fluorescent in situ hybridization (FISH) microscopy method. Passing-Bablok regression analyses revealed the sxtA assay to overestimate abundances when <5 cell equivalents A. catenella DNA were analysed, but otherwise was closer to microscopy estimates than the rDNA assay, which overestimated abundance across the full range of concentrations analysed, indicative of a copy number difference between the bloom population and a culture used for assay calibration a priori. In contrast, the sxtA assay performed more consistently, indicating less copy number variation. The sxtA assay was generally reliable, fast and effective in quantifying A. catenella and was predictive of PST contamination of shellfish.
Kretzschmar, AL, Verma, A, Kohli, G & Murray, S 2019, 'Development of a quantitative PCR assay for the detection and enumeration of a potentially ciguatoxin-producing dinoflagellate, Gambierdiscus lapillus (Gonyaulacales, Dinophyceae).', PloS one, vol. 14, no. 11.View/Download from: Publisher's site
Ciguatera fish poisoning (CFP) is an illness contracted through the ingestion of seafood containing ciguatoxins. It is prevalent in tropical regions worldwide, including in Australia. Ciguatoxins are produced by some species of Gambierdiscus. Therefore, screening of Gambierdiscus species identification through quantitative PCR (qPCR), along with the determination of species toxicity, can be useful in monitoring potential ciguatera risk in these regions. In Australia, CFP is prevalent in tropical Queensland and increasingly in sub-tropical regions of Australia, but has a report rate of approximately 10%. Yet the identity, distribution and abundance of ciguatoxin producing Gambierdiscus spp. is largely unknown. In this study, we developed a rapid qPCR assay to quantify the presence and abundance of Gambierdiscus lapillus, a likely ciguatoxic species first described from Australia. We assessed the specificity and efficiency of the qPCR assay. The assay was tested on 25 environmental samples from the Heron Island reef in the southern Great Barrier Reef, a ciguatera endemic region, to determine the presence and patchiness of this species across samples from Chnoospora sp., Padina sp. and Sargassum sp. macroalgal hosts.
Verma, A, Barua, A, Ruvindy, R, Savela, H, Ajani, PA & Murray, SA 2019, 'The Genetic Basis of Toxin Biosynthesis in Dinoflagellates.', Microorganisms, vol. 7, no. 8.View/Download from: Publisher's site
In marine ecosystems, dinoflagellates can become highly abundant and even dominant at times, despite their comparatively slow growth rates. One factor that may play a role in their ecological success is the production of complex secondary metabolite compounds that can have anti-predator, allelopathic, or other toxic effects on marine organisms, and also cause seafood poisoning in humans. Our knowledge about the genes involved in toxin biosynthesis in dinoflagellates is currently limited due to the complex genomic features of these organisms. Most recently, the sequencing of dinoflagellate transcriptomes has provided us with valuable insights into the biosynthesis of polyketide and alkaloid-based toxin molecules in dinoflagellate species. This review synthesizes the recent progress that has been made in understanding the evolution, biosynthetic pathways, and gene regulation in dinoflagellates with the aid of transcriptomic and other molecular genetic tools, and provides a pathway for future studies of dinoflagellates in this exciting omics era.
Verma, A, Kazandjian, A, Sarowar, C, Harwood, DT, Murray, JS, Pargmann, I, Hoppenrath, M & Murray, SA 2019, 'Morphology and Phylogenetics of Benthic Prorocentrum Species (Dinophyceae) from Tropical Northwestern Australia.', Toxins, vol. 11, no. 10.View/Download from: Publisher's site
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.
Kretzschmar, AL, Verma, A, Murray, S, Kahlke, T, Fourment, M & Darling, A 2019, 'Trial by phylogenetics - Evaluating the Multi-Species Coalescent for phylogenetic inference on taxa with high levels of paralogy (Gonyaulacales, Dinophyceae)'.View/Download from: Publisher's site
ABSTRACT From publicly available next-gen sequencing datasets of non-model organisms, such as marine protists, arise opportunities to explore their evolutionary relationships. In this study we explored the effects that dataset and model selection have on the phylogenetic inference of the Gonyaulacales, single celled marine algae of the phylum Dinoflagellata with genomes that show extensive paralogy. We developed a method for identifying and extracting single copy genes from RNA-seq libraries and compared phylogenies inferred from these single copy genes with those inferred from commonly used genetic markers and phylogenetic methods. Comparison of two datasets and three different phylogenetic models showed that exclusive use of ribosomal DNA sequences, maximum likelihood and gene concatenation showed very different results to that obtained with the multi-species coalescent. The multi-species coalescent has recently been recognized as being robust to the inclusion of paralogs, including hidden paralogs present in single copy gene sets (pseudoorthologs). Comparisons of model fit strongly favored the multi-species coalescent for these data, over a concatenated alignment (single tree) model. Our findings suggest that the multi-species coalescent (inferred either via Maximum Likelihood or Bayesian Inference) should be considered for future phylogenetic studies of organisms where accurate selection of orthologs is difficult.
Verma, A, Kohli, GS, Harwood, DT, Ralph, PJ & Murray, SA 2019, 'Transcriptomic investigation into polyketide toxin synthesis in Ostreopsis (Dinophyceae) species.', Environmental Microbiology, vol. 21, no. 11, pp. 4196-4211.View/Download from: Publisher's site
In marine ecosystems, dinoflagellates can become highly abundant and even dominant at times, despite their comparatively slow growth. Their ecological success may be related to their production of complex toxic polyketide compounds. Ostreopsis species produce potent palytoxin-like compounds (PLTX), which are associated with human skin and eye irritations, and illnesses through the consumption of contaminated seafood. To investigate the genetic basis of PLTX-like compounds, we sequenced and annotated transcriptomes from two PLTX-producing Ostreopsis species; O. cf. ovata, O. cf. siamensis, one non-PLTX producing species, O. rhodesae and compared them to a close phylogenetic relative and non-PLTX producer, Coolia malayensis. We found no clear differences in the presence or diversity of ketosynthase and ketoreductase transcripts between PLTX producing and non-producing Ostreopsis and Coolia species, as both groups contained >90 and > 10 phylogenetically diverse ketosynthase and ketoreductase transcripts, respectively. We report for the first-time type I single-, multi-domain polyketide synthases (PKSs) and hybrid non-ribosomal peptide synthase/PKS transcripts from all species. The long multi-modular PKSs were insufficient by themselves to synthesize the large complex polyether backbone of PLTX-like compounds. This implies that numerous PKS domains, including both single and multi-, work together on the biosynthesis of PLTX-like and other related polyketide compounds.
Kretzschmar, AL, Larsson, ME, Hoppenrath, M, Doblin, MA & Murray, SA 2019, 'Characterisation of Two Toxic Gambierdiscus spp. (Gonyaulacales, Dinophyceae) from the Great Barrier Reef (Australia): G. lewisii sp. nov. and G. holmesii sp. nov', PROTIST, vol. 170, no. 6.View/Download from: Publisher's site
Brown, P, RELISH Consortium & Zhou, Y 2019, 'Large expert-curated database for benchmarking document similarity in biomedical literature search', Database: the journal of biological databases and curation, vol. 2019, pp. 1-66.View/Download from: Publisher's site
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency–Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.
Litaker, RW, Fraga, S, Montresor, M, Brosnahan, M, Anderson, D, Hoppenrath, M, Murray, S, Wolny, J, John, U, Sampedro, N, Larsen, J & Calado, A 2018, 'A practical guide to the new nomenclature for species within the "Alexandrium tamarense" species complex', Harmful algae news / Unesco; IOC; Intergovernmental Oceanographic Commission, vol. 61, pp. 13-15.
Ruvindy, R, Bolch, CJ, MacKenzie, L, Smith, KF & Murray, SA 2018, 'qPCR Assays for the Detection and Quantification of Multiple Paralytic Shellfish Toxin-Producing Species of Alexandrium.', Frontiers in microbiology, vol. 9.View/Download from: Publisher's site
Paralytic shellfish toxin producing dinoflagellates have negatively impacted the shellfish aquaculture industry worldwide, including in Australia and New Zealand. Morphologically identical cryptic species of dinoflagellates that may differ in toxicity, in particular, species of the former Alexandrium tamarense species complex, co-occur in Australia, as they do in multiple regions in Asia and Europe. To understand the dynamics and the ecological drivers of the growth of each species in the field, accurate quantification at the species level is crucial. We have developed the first quantitative polymerase chain reaction (qPCR) primers for A. australiense, and new primers targeting A. ostenfeldii, A. catenella, and A. pacificum. We showed that our new primers for A. pacificum are more specific than previously published primer pairs. These assays can be used to quantify planktonic cells and cysts in the water column and in sediment samples with limits of detection of 2 cells/L for the A. catenella and A. australiense assays, 2 cells/L and 1 cyst/mg sediment for the A. pacificum assay, and 1 cells/L for the A. ostenfeldii assay, and efficiencies of >90%. We utilized these assays to discriminate and quantify co-occurring A. catenella, A. pacificum, and A. australiense in samples from the east coast of Tasmania, Australia.
Ajani, PA, Larsson, M, Woodcock, S, Rubio, A, Farrell, H, Brett, S & Murray, S 2018, 'Bloom drivers of the potentially harmful dinoflagellate Prorocentrum minimum (Pavillard) Schiller in a south eastern temperate Australian estuary', Estuarine, Coastal and Shelf Science, vol. 215.View/Download from: Publisher's site
Farrell, H, Ajani, PA, Murray, S, Baker, P, Webster, G, Brett, S & Zammit, A 2018, 'Diarrhetic Shellfish Toxin Monitoring in Commercial Wild Harvest Bivalve Shellfish in New South Wales, Australia', Toxins, vol. 10, no. 11.View/Download from: Publisher's site
Ajani, PA, Kahlke, T, Siboni, N, Carney, R, Murray, S & Seymour, J 2018, 'The microbiome of the cosmopolitan diatom Leptocylindrus reveals significant spatial and temporal variability', Frontiers in Microbiology, vol. 9.View/Download from: Publisher's site
Ajani, PA, Verma, A, Lassudrie, M, Doblin, MA & Murray, SA 2018, 'A new diatom species P. hallegraeffii sp. nov. belonging to the toxic genus Pseudo-nitzschia (Bacillariophyceae) from the East Australian Current.', PloS one, vol. 13, no. 4, pp. e0195622-e0195622.View/Download from: Publisher's site
A new species belonging to the toxin producing diatom genus Pseudo-nitzschia, P. hallegraeffii sp. nov., is delineated and described from the East Australian Current (EAC). Clonal cultures were established by single cell isolation from phytoplankton net hauls collected as part of a research expedition in the EAC region in 2016 on the RV Investigator. Cultures were assessed for their morphological and genetic characteristics, their sexual compatibility with other Pseudo-nitzschia species, and their ability to produce domoic acid. Light and transmission electron microscopy revealed cells which differed from their closest relatives by their cell width, rows of poroids, girdle band structure and density of band straie. Phylogenetic analyses based on sequencing of nuclear-encoded ribosomal deoxyribonucleic acid (rDNA) regions showed this novel genotype clustered within the P. delicatissima complex, but formed a discrete clade from its closest relatives P. dolorosa, P. simulans, P. micropora and P. delicatissima. Complementary base changes (CBCs) were observed in the secondary structure of the 3' nuclear ribosomal transcribed spacer sequence region (ITS2) between P. hallegraeffii sp. nov. and its closest related taxa, P. simulans and P. dolorosa. Under laboratory conditions, and in the absence of any zooplankton cues, strains of P. hallegraeffii sp. nov. did not produce domoic acid (DA) and were not sexually compatible with any other Pseudo-nitzschia clones tested. A total of 18 Pseudo-nitzschia species, including three confirmed toxigenic species (P. cuspidata, P. multistriata and P. australis) have now been unequivocally confirmed from eastern Australia.
Larsson, ME, Laczka, OF, Harwood, DT, Lewis, RJ, Himaya, SWA, Murray, SA & Doblin, MA 2018, 'Toxicology of Gambierdiscus spp. (Dinophyceae) from Tropical and Temperate Australian Waters.', Marine drugs, vol. 16, no. 1.View/Download from: Publisher's site
Ciguatera Fish Poisoning (CFP) is a human illness caused by the consumption of marine fish contaminated with ciguatoxins (CTX) and possibly maitotoxins (MTX), produced by species from the benthic dinoflagellate genus Gambierdiscus. Here, we describe the identity and toxicology of Gambierdiscus spp. isolated from the tropical and temperate waters of eastern Australia. Based on newly cultured strains, we found that four Gambierdiscus species were present at the tropical location, including G. carpenteri, G. lapillus and two others which were not genetically identical to other currently described species within the genus, and may represent new species. Only G. carpenteri was identified from the temperate location. Using LC-MS/MS analysis we did not find any characterized microalgal CTXs (P-CTX-3B, P-CTX-3C, P-CTX-4A and P-CTX-4B) or MTX-1; however, putative maitotoxin-3 (MTX-3) was detected in all species except for the temperate population of G. carpenteri. Using the Ca2+ influx SH-SY5Y cell Fluorescent Imaging Plate Reader (FLIPR) bioassay we found CTX-like activity in extracts of the unidentified Gambierdiscus strains and trace level activity in strains of G. lapillus. While no detectable CTX-like activity was observed in tropical or temperate strains of G. carpenteri, all species showed strong maitotoxin-like activity. This study, which represents the most comprehensive analyses of the toxicology of Gambierdiscus strains isolated from Australia to date, suggests that CFP in this region may be caused by currently undescribed ciguatoxins and maitotoxins.
Dorantes-Aranda, JJ, Campbell, K, Bradbury, A, Elliott, CT, Harwood, DT, Murray, SA, Ugalde, SC, Wilson, K, Burgoyne, M & Hallegraeff, GM 2017, 'Comparative performance of four immunological test kits for the detection of Paralytic Shellfish Toxins in Tasmanian shellfish.', Toxicon, vol. 125, pp. 110-119.View/Download from: Publisher's site
Blooms of the toxic dinoflagellate Alexandrium tamarense (Group 1) seriously impacted the Tasmanian shellfish industry during 2012 and 2015, necessitating product recalls and intensive paralytic shellfish toxin (PST) product testing. The performance of four commercial PST test kits, Abraxis™, Europroxima™, Scotia™ and Neogen™, was compared with the official AOAC LC-FLD method for contaminated mussels and oysters. Abraxis and Europroxima kits underestimated PST in 35-100% of samples when using standard protocols but quantification improved when concentrated extracts were further diluted (underestimation ≤18%). The Scotia kit (cut off 0.2-0.7 mg STX-diHCl eq/kg) delivered 0% false negatives, but 27% false positives. Neogen produced 5% false negatives and 13% false positives when the cut off was altered to 0.5-0.6 mg STX-diHCl eq/kg, the introduction of a conversion step eliminated false negatives. Based on their sensitivity, ease of use and performance, the Neogen kit proved the most suitable kit for use with Tasmanian mussels and oysters. Once formally validated for regulatory purposes, the Neogen kit could provide shellfish growers with a rapid tool for harvesting decisions at the farm gate. Effective rapid screening preventing compliant samples undergoing testing using the more expensive and time consuming LC-FLD method will result in significant savings in analytical costs.
Between 2014 and 2016, five cases of ciguatera fish poisoning (CFP), involving twenty four individuals, were linked to Spanish Mackerel (Scomberomorus commerson) caught in the coastal waters of the state of New South Wales (NSW) on the east coast of Australia. Previously, documented cases of CFP in NSW were few, and primarily linked to fish imported from other regions. Since 2015, thirteen individuals were affected across four additional CFP cases in NSW, linked to fish imported from tropical locations. The apparent increase in CFP in NSW from locally sourced catch, combined with the risk of CFP from imported fish, has highlighted several considerations that should be incorporated into risk management strategies to minimize CFP exposure for seafood consumers.
Kohli, GS, Campbell, K, John, U, Smith, KF, Fraga, S, Rhodes, LL & Murray, SA 2017, 'Role of Modular Polyketide Synthases in the Production of Polyether Ladder Compounds in Ciguatoxin-Producing Gambierdiscus polynesiensis and G. excentricus (Dinophyceae).', Journal of Eukaryotic Microbiology, pp. 1-16.View/Download from: Publisher's site
Gambierdiscus, a benthic dinoflagellate, produces ciguatoxins that cause the human illness Ciguatera. Ciguatoxins are polyether ladder compounds that have a polyketide origin, indicating that polyketide synthases (PKS) are involved in their production. We sequenced transcriptomes of Gambierdiscus excentricus and Gambierdiscus polynesiensis and found 264 contigs encoding single domain ketoacyl synthases (KS; G. excentricus: 106, G. polynesiensis: 143) and ketoreductases (KR; G. excentricus: 7, G. polynesiensis: 8) with sequence similarity to type I PKSs, as reported in other dinoflagellates. In addition, 24 contigs (G. excentricus: 3, G. polynesiensis: 21) encoding multiple PKS domains (forming typical type I PKSs modules) were found. The proposed structure produced by one of these megasynthases resembles a partial carbon backbone of a polyether ladder compound. Seventeen contigs encoding single domain KS, KR, s-malonyltransacylase, dehydratase and enoyl reductase with sequence similarity to type II fatty acid synthases (FAS) in plants were found. Type I PKS and type II FAS genes were distinguished based on the arrangement of domains on the contigs and their sequence similarity and phylogenetic clustering with known PKS/FAS genes in other organisms. This differentiation of PKS and FAS pathways in Gambierdiscus is important, as it will facilitate approaches to investigating toxin biosynthesis pathways in dinoflagellates.
Kohli, GS, Haslauer, K, Sarowar, C, Kretzschmar, AL, Boulter, M, Harwood, DT, Laczka, O & Murray, SA 2017, 'Qualitative and quantitative assessment of the presence of ciguatoxin, P-CTX-1B, in Spanish Mackerel (Scomberomorus commerson) from waters in New South Wales (Australia).', Toxicology Reports, vol. 4, pp. 328-334.View/Download from: Publisher's site
Ciguatera Fish Poisoning (CFP) is a tropical disease caused by the consumption of fish contaminated with ciguatoxins (CTXs). Currently, the only feasible prevention methods for CFP are to avoid the consumption of fish of certain species from some regions, avoid larger fish of certain species, or avoid all fish caught from specific regions. Here, we quantified levels of P-CTX-1B in Spanish Mackerel (Scomberomorus commerson), which is the main fish species that causes CFP in New South Wales and Queensland, Australia, using LC-MS detection against a toxin standard. We found detectable P-CTX-1B in both flesh and liver tissues in fish from New South Wales (n = 71, 1.4% prevalence rate, with a confidence interval of 1%-4%, and 7% prevalence, 1%-12%, in flesh and liver, respectively). In the small sample of fish from Queensland, there was a 46% prevalence (19-73%, n = 13). Toxin levels found were 0.13 μg kg-1 to <0.1 μg kg-1 in flesh, and 1.39 μg kg-1 to <0.4 μg kg-1 in liver, indicating that liver tissue had a significantly higher concentration (∼5 fold) of P-CTX-1B. No apparent relationship was observed between the length or weight of S. commerson and the detection of P-CTX-1B in this study. Footnote.
McLeod, C, Dowsett, N, Hallegraeff, G, Harwood, DT, Hay, B, Ibbott, S, Malhi, N, Murray, S, Smith, K, Tan, J & Turnbull, A 2017, 'Accumulation and depuration of paralytic shellfish toxins by Australian abalone Haliotis rubra: Conclusive association with Gymnodinium catenatum dinoflagellate blooms', FOOD CONTROL, vol. 73, pp. 971-980.View/Download from: Publisher's site
Smith, KF, Kohli, GS, Murray, SA & Rhodes, LL 2017, 'Assessment of the metabarcoding approach for community analysis of benthic-epiphytic dinoflagellates using mock communities', New Zealand Journal of Marine and Freshwater Research, pp. 1-22.View/Download from: Publisher's site
© 2017 The Royal Society of New Zealand In this study, we assessed the use of DNA metabarcoding as a method for biodiversity assessment of benthic-epiphytic dinoflagellate communities and for detecting rare, toxin-producing taxa. Mock communities and three primer pairs were used to establish the recovery of species signal and quantitative representation of species in the samples, as well as to determine primer biases, bioinformatic filtering steps, and threshold levels. Samples were analysed using high-throughput sequencing Illumina ™ MiSeq technology. We did not find a relationship between read number and cell abundance for all treatments. However, the method was extremely sensitive, with two of the primer pairs detecting a single cell representing less than 0.001% of the cells in the sample. Benthic and epiphytic dinoflagellate communities were also collected from the Bay of Islands (Northland, New Zealand). Dinophyceae species richness was much higher when samples were analysed using metabarcoding than when analysed by microscopy, and we detected several new taxonomic records for New Zealand.
Van Dolah, FM, Kohli, GS, Morey, JS & Murray, SA 2017, 'Both modular and single-domain Type I polyketide synthases are expressed in the brevetoxin-producing dinoflagellate, Karenia brevis (Dinophyceae)', JOURNAL OF PHYCOLOGY, vol. 53, no. 6, pp. 1325-1339.View/Download from: Publisher's site
Kretzschmar, AL, Verma, A, Harwood, T, Hoppenrath, M & Murray, S 2017, 'Characterization of Gambierdiscus lapillus sp. nov. (Gonyaulacales, Dinophyceae): a new toxic dinoflagellate from the Great Barrier Reef (Australia).', Journal of phycology, vol. 53, no. 2, pp. 283-297.View/Download from: Publisher's site
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.
Murray, SA, Ajani, P, Kretzschmar, AL & Verma, A 2017, 'Response to "More surprises in the global greenhouse: Human health impacts form recent toxic marine aerosol formulations, due to centennial alterations or world-wide coastal food webs".', Marine Pollution Bulletin, vol. 123, no. 1-2, pp. 415-417.View/Download from: Publisher's site
Rhodes, L, Smith, KF, Verma, A, Curley, BG, Harwood, DT, Murray, S, Kohli, GS, Solomona, D, Rongo, T, Munday, R & Murray, SA 2017, 'A new species of Gambierdiscus (Dinophyceae) from the south-west Pacific: Gambierdiscus honu sp. nov.', Harmful Algae, vol. 65, pp. 61-70.View/Download from: Publisher's site
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.
Farrell, H, O'Connor, W, Seebacher, F, Harwood, DT & Murray, S 2016, 'Molecular Detection Of The Sxta Gene From Saxitoxin-Producing Alexandrium Minutum In Commercial Oyster', The Journal of Shellfish Research, vol. 35, no. 1, pp. 169-177.View/Download from: Publisher's site
The production of toxic secondary metabolites by marine phytoplankton and their accumulation in molluscs and fish has ecosystem-wide and human health impacts.
Kohli, GS, John, U, Van Dolah, FM & Murray, SA 2016, 'Evolutionary distinctiveness of fatty acid and polyketide synthesis in eukaryotes', ISME JOURNAL, vol. 10, no. 8, pp. 1877-1890.View/Download from: Publisher's site
Murray, SA, Smith, K, Rhodes, L, Verma, A, Curley, B, Harwood, DT, Kohli, G, Solomona, D, Rongo, T & Munday, R 2016, 'A new Gambierdiscus species (Dinophyceae) from Rarotonga, Cook Islands: Gambierdiscus cheloniae sp. nov', Harmful Algae, vol. 60, pp. 45-56.View/Download from: Publisher's site
Verma, A, Hoppenrath, M, Harwood, T, Brett, S, Rhodes, L & Murray, S 2016, 'Molecular phylogeny, morphology and toxigenicity of Ostreopsis cf. siamensis (Dinophyceae) from temperate south-east Australia', PHYCOLOGICAL RESEARCH, vol. 64, no. 3, pp. 146-159.View/Download from: Publisher's site
Verma, A, Hoppenrath, M, Jose Dorantes-Aranda, J, Harwood, DT & Murray, SA 2016, 'Molecular and phylogenetic characterization of Ostreopsis (Dinophyceae) and the description of a new species, Ostreopsis rhodesae sp nov., from a subtropical Australian lagoon', HARMFUL ALGAE, vol. 60, pp. 116-130.View/Download from: Publisher's site
Ajani, PA, Armbrecht, L, Oliver, K, Kohli, G & Murray, S 2016, 'Diversity, temporal distribution and physiology of the centric diatom Leptocylindrus (Bacillariophyta) from a southern hemisphere upwelling system', Diatom Research.View/Download from: Publisher's site
The marine diatom Leptocylindrus is a major component of phytoplankton blooms in coastal ecosystems and upwelling regions worldwide, however, little is known about this genus in the southern hemisphere. Whilst Leptocylindrus danicus has been reported from south-eastern (SE) Australia since the 1930s, there has been neither unequivocal species identification nor focused examination of the temporal abundance of Leptocylindrus in this region. Such investigations are crucial in the context of climate change and the strengthening of the East Australian Current, which is expected to result in alterations to the seasonal abundance and distribution of Leptocylindrus along the east Australian coast. Thus we also describe the temporal distribution of Leptocylindrus based on 50 years of records, revealing that this diatom is a key component of the seasonal phytoplankton cycle, with greatest abundance in the austral spring and summer. Using light and transmission electron microscopy and molecular phylogenetics based on the nuclear-encoded ITS1–5.8S–ITS2 rDNA region, our study unambiguously revealed three species, L. danicus, Leptocylindrus convexus and Leptocylindrus aporus from 34 clonal isolates from SE Australia, with the majority (82%) of strains identified as L. danicus. Furthermore, we investigated the growth, auxospore and resting spore formation of the most commonly occurring species, L. danicus, under four temperature and irradiance scenarios. The diatom reached maximum growth rates (µMax, 1.71 divisions day−1) under relatively high temperatures (25°C) and light conditions (100 µmol photons m−2 s−1) between days 2 and 7 of the experiment. When temperature and light regimes were reduced (18°C, 50 µmol photons m−2 s−1) auxospores and resting spores were formed. The rapid growth rate and potential of L. danicus to form auxospores are important survival mechanisms in coastal upwelling systems and likely to result in the continued success of this species in Eastern Austr...
Ajani, PA, Hallegraeff, GM, Allen, D, Coughlan, A, Richardson, AJ, Armand, LK, Ingleton, T & Murray, SA 2016, 'Establishing baselines: a review of eighty years of phytoplankton diversity and biomass in southeastern Australia', Oceanography and Marine Biology: an annual review, vol. 54, pp. 387-412.View/Download from: Publisher's site
Establishing trends in phytoplankton diversity and biomass, particularly in relation to climate change,
is challenging and requires reference to baseline observations. Detecting changes over seasonal, interannual,
and interdecadal timescales requires the collection of long-term
datasets. Australian marine
ecosystems and their constituent phytoplankton have been studied only in the last approximately 100
years, focused on the south-eastern
coast of Australia, as this is the site of the major population centres.
The coastline of south-eastern
Australia is dominated by the dynamic East Australian Current, as
well as a diverse range of estuaries, each with its own distinct riverine inputs, tidal cycles, and flushing
times. Warming of the East Australian Current over the past century at two to three times the global
average, combined with increased nutrient loads and encroaching coastal urbanization, is likely to
have had an impact on the coastal environment, ecosystems, and supported phytoplankton communities.
Even though sporadic research has been undertaken into the diversity, distribution, and ecology
of marine and estuarine phytoplankton over the past 80 years, the first long-term
have only recently been completed. In this review, we conducted a meta-analysis
of 90 phytoplankton
studies from 1933 to 2015 and examined the major themes covered and methodologies used.
We examined five datasets spanning the past 50 years from the long-term
coastal station off shore
from Port Hacking, Sydney. Whilst species composition and distribution appear to have changed over
time, our knowledge of their systematics and identification has also expanded. Sixty-three
genera, and about 19 potentially harmful species have been described from south-eastern
waters over the past 30 years, and many represent first-time
Australian records. The emerging use of
sequencing and quantitative molecular methods for phytoplankton ide...
Ajani, PA, Hallegraeff, GM, Allen, D, Coughlan, A, Richardson, AJ, Armand, LK, Ingleton, T & Murray, SA 2016, 'Establishing baselines: Eighty years of phytoplankton diversity and biomass in south-eastern Australia', vol. 54, pp. 387-412.View/Download from: Publisher's site
© 2016 by R.N. Hughes, D.J. Hughes, I.P. Smith, A.C. Dale. All rights reserved. Establishing trends in phytoplankton diversity and biomass, particularly in relation to climate change, is challenging and requires reference to baseline observations. Detecting changes over seasonal, interannual, and interdecadal timescales requires the collection of long-term datasets. Australian marine ecosystems and their constituent phytoplankton have been studied only in the last approximately 100 years, focused on the south-eastern coast of Australia, as this is the site of the major population centres. The coastline of south-eastern Australia is dominated by the dynamic East Australian Current, as well as a diverse range of estuaries, each with its own distinct riverine inputs, tidal cycles, and flushing times. Warming of the East Australian Current over the past century at two to three times the global average, combined with increased nutrient loads and encroaching coastal urbanization, is likely to have had an impact on the coastal environment, ecosystems, and supported phytoplankton communities. Even though sporadic research has been undertaken into the diversity, distribution, and ecology of marine and estuarine phytoplankton over the past 80 years, the first long-term time-series investigations have only recently been completed. In this review, we conducted a meta-analysis of 90 phytoplankton studies from 1933 to 2015 and examined the major themes covered and methodologies used. We examined five datasets spanning the past 50 years from the long-term coastal station off shore from Port Hacking, Sydney. Whilst species composition and distribution appear to have changed over time, our knowledge of their systematics and identification has also expanded. Sixty-three species, 5 genera, and about 19 potentially harmful species have been described from south-eastern Australian waters over the past 30 years, and many represent first-time Australian records. The emerging use of nex...
Ajani, PA, Kim, JH, Han, MS & Murray, SA 2016, 'The first report of the potentially harmful diatom Pseudo-nitzschia caciantha from Australian coastal waters.', Phycological Research, vol. 64, no. 4, pp. 312-317.View/Download from: Publisher's site
Davies, CH, Coughlan, A, Hallegraeff, G, Ajani, P, Armbrecht, L, Atkins, N, Bonham, P, Brett, S, Brinkman, R, Burford, M, Clementson, L, Coad, P, Coman, F, Davies, D, Dela-Cruz, J, Devlin, M, Edgar, S, Eriksen, R, Furnas, M, Hassler, C, Hill, D, Holmes, M, Ingleton, T, Jameson, I, Leterme, SC, Lonborg, C, McLaughlin, J, McEnnulty, F, McKinnon, AD, Miller, M, Murray, S, Nayar, S, Patten, R, Pritchard, T, Proctor, R, Purcell-Meyerink, D, Raes, E, Rissik, D, Ruszczyk, J, Slotwinski, A, Swadling, KM, Tattersall, K, Thompson, P, Thomson, P, Tonks, M, Trull, TW, Uribe-Palomino, J, Waite, AM, Yauwenas, R, Zammit, A & Richardson, AJ 2016, 'A database of marine phytoplankton abundance, biomass and species composition in Australian waters', SCIENTIFIC DATA, vol. 3.View/Download from: Publisher's site
Murray, SA, Suggett, DJ, Seymour, JR, Doblin, M, Kohli, GS, Fabris, M & Ralph, PJ 2016, 'Unravelling the functional genetics of dinoflagellates: a review of approaches and opportunities', Perspectives in Phycology, vol. 3, no. 1, pp. 37-52.View/Download from: Publisher's site
Dinoflagellates occupy an extraordinarily diverse array of ecological niches. Their success stems from a suite of functional and ecological strategies, including the production of secondary metabolites with anti-predator or allelopathic impacts, nutritional flexibility, and the ability to form symbiotic relationships. Despite their ecological importance, we currently have a poor understanding of the genetic basis for many of these strategies, due to the complex genomes of dinoflagellates. Genomics and transcriptomic sequencing approaches are now providing the first insights into the genetic basis of some dinoflagellate functional traits, providing the opportunity for novel ecological experiments, novel methods for monitoring of harmful biotoxins, and allowing us to investigate the production of ecologically and economically important compounds such as the long chain polyunsaturated fatty acid, docosahexanoic acid and the climatically important metabolite, dimethylsulfoniopropionate. Despite these advances, we still generally lack the ability to genetically manipulate species, which would enable the confirmation of biosynthetic pathways and the development of novel bio-engineering applications. Here, we describe advances in understanding the genetic basis of dinoflagellate ecology, and propose biotechnological approaches that could be applied to further transform our understanding of this unique group of eukaryotes.
Farrell, H, Seebacher, F, O'Connor, W, Zammit, A, Harwood, DT & Murray, S 2015, 'Warm temperature acclimation impacts metabolism of paralytic shellfish toxins from Alexandrium minutum in commercial oysters.', Global Change Biology, vol. 21, no. 9, pp. 3402-3413.View/Download from: Publisher's site
Species of Alexandrium produce potent neurotoxins termed paralytic shellfish toxins and are expanding their ranges worldwide, concurrent with increases in sea surface temperature. The metabolism of molluscs is temperature dependent, and increases in ocean temperature may influence both the abundance and distribution of Alexandrium and the dynamics of toxin uptake and depuration in shellfish. Here, we conducted a large-scale study of the effect of temperature on the uptake and depuration of paralytic shellfish toxins in three commercial oysters (Saccostrea glomerata and diploid and triploid Crassostrea gigas, n = 252 per species/ploidy level). Oysters were acclimated to two constant temperatures, reflecting current and predicted climate scenarios (22 and 27 °C), and fed a diet including the paralytic shellfish toxin-producing species Alexandrium minutum. While the oysters fed on A. minutum in similar quantities, concentrations of the toxin analogue GTX1,4 were significantly lower in warm-acclimated S. glomerata and diploid C. gigas after 12 days. Following exposure to A. minutum, toxicity of triploid C. gigas was not affected by temperature. Generally, detoxification rates were reduced in warm-acclimated oysters. The routine metabolism of the oysters was not affected by the toxins, but a significant effect was found at a cellular level in diploid C. gigas. The increasing incidences of Alexandrium blooms worldwide are a challenge for shellfish food safety regulation. Our findings indicate that rising ocean temperatures may reduce paralytic shellfish toxin accumulation in two of the three oyster types; however, they may persist for longer periods in oyster tissue.
Gao, Y, Yu, R-C, Murray, SA, Chen, J-H, Kang, Z-J, Zhang, Q-C, Kong, F-Z & Zhou, M-J 2015, 'High Specificity of a Quantitative PCR Assay Targeting a Saxitoxin Gene for Monitoring Toxic Algae Associated with Paralytic Shellfish Toxins in the Yellow Sea', APPLIED AND ENVIRONMENTAL MICROBIOLOGY, vol. 81, no. 20, pp. 6973-6981.View/Download from: Publisher's site
Kohli, GS, John, U, Figueroa, RI, Rhodes, LL, Harwood, DT, Groth, M, Bolch, CJS & Murray, SA 2015, 'Polyketide synthesis genes associated with toxin production in two species of Gambierdiscus (Dinophyceae)', BMC GENOMICS, vol. 16.View/Download from: Publisher's site
Murray, SA, Diwan, R, Orr, RJS, Kohli, GS & John, U 2015, 'Gene duplication, loss and selection in the evolution of saxitoxin biosynthesis in alveolates', MOLECULAR PHYLOGENETICS AND EVOLUTION, vol. 92, pp. 165-180.View/Download from: Publisher's site
Murray, SA, Kohli, GS, Farrell, H, Spiers, ZB, Place, AR, Dorantes-Aranda, JJ & Ruszczyk, J 2015, 'A fish kill associated with a bloom of Amphidinium carterae in a coastal lagoon in Sydney, Australia.', Harmful Algae, vol. 49, pp. 19-28.View/Download from: Publisher's site
We report on a dense bloom (1.80 105 cells mL 1
) of the marine dinoflagellate species Amphidinium
carterae (Genotype 2) in a shallow, small intermittently open coastal lagoon in south eastern Australia.
This bloom co-occurred with the deaths of >300 individuals of three different species of fish. The
opening of the lagoon to the ocean, as well as localized high nutrient levels, preceded the observations of
very high cell numbers. A. carterae is usually benthic and sediment-dwelling, but temporarily became
abundant throughout the water column in this shallow (<2 m) sandy habitat. Histopathological results
showed that the Anguilla reinhardtii individuals examined had damage to epithelial and gill epithelial
cells. An analysis of the bloom water indicated the presence of a compound with a retention time and UV
spectra similar to Luteophanol A, a compound known from a strain of Amphidinium. Assays with a fish gill
cell line were conducted using a purified compound from cells concentrated from the bloom, and was
found to cause a loss of 87% in cell viability in 6 h. The fish deaths were likely due to the low dissolved
oxygen levels in the water and/or the presence of Luteophanol A-like compounds released during the
John, U, Litaker, RW, Montresor, M, Murray, S, Brosnahan, ML & Anderson, DM 2014, 'Formal Revision of the Alexandrium tamarense Species Complex (Dinophyceae) Taxonomy: The Introduction of Five Species with Emphasis on Molecular-based (rDNA) Classification', PROTIST, vol. 165, no. 6, pp. 779-804.View/Download from: Publisher's site
John, U, Litaker, W, Montresor, M, Murray, SA, Brosnahan, ML & Anderson, DM 2014, 'Proposal to reject the name Gonyaulax catenella (Alexandrium catenella) (Dinophyceae)', Taxon, vol. 63, no. 4, pp. 932-933.View/Download from: Publisher's site
Keeling, PJ, Burki, F, Wilcox, HM, Allam, B, Allen, EE, Amaral-Zettler, LA, Armbrust, V, Archibald, JM, Bharti, AK, Bell, CJ, Beszteri, B, Bidle, KD, Cameron, CT, Campbell, L, Caron, DA, Cattolico, RA, Collier, JL, Coyne, K, Davy, SK, Deschamps, P, Dyhrman, S, Edvardsen, B, Gates, RD, Gobler, CJ, Greenwood, SJ, Guida, SM, Jacobi, JL, Jakobsen, KS, James, ER, Jenkins, B, John, U, Johnson, MD, Juhl, AR, Kamp, A, Katz, LA, Kiene, R, Kudryavtsev, A, Leander, BS, Lin, S, Lovejoy, C, Lynn, D, Marchetti, A, McManus, G, Nedelcu, AM, Menden-Deuer, S, Miceli, C, Mock, T, Montresor, M, Moran, MA, Murray, SA, Nadathur, G, Nagai, S, Ngam, PB, Palenik, B, Pawlowski, J, Petroni, G, Piganeau, G, Posewitz, MC, Rengefors, K, Romano, G, Rumpho, ME, Rynearson, T, Schilling, KB, Schroeder, DC, Simpson, AG, Slamovits, CH, Smith, DR, Smith, J, Smith, SR, Sosik, HM, Stief, P, Theriot, E, Twary, SN, Umale, PE, Vaulot, D, Wawrik, B, Wheeler, GL, Wilson, WH, Xu, Y, Zingone, A & Worden, AZ 2014, 'The Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP): Illuminating the Functional Diversity of Eukaryotic Life in the Oceans through Transcriptome Sequencing', Plos Biology, vol. 12, no. 6.View/Download from: Publisher's site
Kohli, GS, Murray, SA, Neilan, BA, Rhodes, L, Harwood, T, Smith, KF, Meyer, L, Capper, A, Brett, S & Hallegraeff, GM 2014, 'High abundance of the potentially maitotoxic dinoflagellate Gambierdiscus carpenteri in temperate waters of New South Wales, Australia', Harmful Algae, vol. 39, pp. 134-145.View/Download from: Publisher's site
Species of the genus Gambierdiscus are epiphytic dinoflagellates well known from tropical coral reef areas at water temperatures from 24 to 29 °C. Gambierdiscus spp. are able to produce ciguatoxins (CTXs) known to bioaccumulate in fish, and the ingestion of tropical fish that accumulated CTXs and possibly also maitotoxins (MTXs) can cause ciguatera fish poisoning (CFP) in humans. In Australia, ciguatera poisonings have been reported in tropical parts of Queensland and the Northern Territory. Here, we report for the first time the seasonal abundance (AprilMay 2012/13) of Gambierdiscus spp. (up to 65658255 cells g-1 wet weight algae) from Merimbula and Wagonga Inlets in temperate southern New South Wales, Australia (37° S) at water temperatures of 16.517 °C. These are popular shellfish aquaculture and recreational fisheries areas with no reports of ciguatera poisoning. Sequencing of a region of the 28S rRNA gene led to the conclusive identification of Gambierdiscus carpenteri. The cells differed however from the Belize type description, including the absence of a thecal groove, dorsal rostrum and variable hatchet- to rectangular-shaped 2' plate, and were morphologically more similar to Gambierdiscus toxicus. To study the dinoflagellate community structure in detail, a pyrosequencing approach based on the 18S rRNA gene was applied, which confirmed the presence of a single Gambierdiscus species only. Neither CTXs nor MTXs were detected in natural bloom material by LCMS/MS; however, the extracts were found to be toxic via mouse-bioassay, with symptoms suggestive of poisoning by MTX-like compounds. Understanding the abundance of Gambierdiscus populations in areas with no apparent human health impacts is important towards defining the alternate conditions where sparse populations can create ciguatera problems.
Kohli, GS, Neilan, BA, Brown, MV, Hoppenrath, M & Murray, SA 2014, 'Cob gene pyrosequencing enables characterisation of benthic dinoflagellate diversity and biogeography', Environmental Microbiology, vol. 16, no. 2, pp. 467-485.View/Download from: Publisher's site
Kohli, GS, Papiol, GG, Rhodes, L, Harwood, T, Selwood, A, Jerrett, A, Murray, SA & Neilan, BA 2014, 'A feeding study to probe the uptake of Maitotoxin by snapper (Pagrus auratus)', Harmful Algae, vol. 37, pp. 125-132.View/Download from: Publisher's site
The role of ciguatoxins (CTX) in Ciguatera fish poisoning (CFP) has been investigated previously, but little is known about Maitotoxin (MTX) and whether it plays a significant role in causing human illness. The MTXs are known to have slightly higher potency than CTXs when administered intraperitoneally in mice, but are less potent when administered orally, due to their water solubility. It is not known whether MTXs accumulate in carnivorous fish tissues, and to investigate this further fish feeding trials with snapper (Pagrus auratus) were undertaken. Replicate P. auratus were fed with juvenile mullet (Aldrichetta forsteri) injected with a pellet of a known quantity of Gambierdiscus australes, which is a known producer of MTX. The levels of MTX in different fish tissues were determined using two newly developed sensitive LCMS/MS assays for MTX that monitor either a specific cleavage fragment (generated from micro-scale oxidation of the intact toxin) or the intact toxin itself. The investigations revealed the presence of MTX in P. auratus viscera, liver and muscle samples. The presence of Gambierdiscus-related genes in P. auratus digestive organs was confirmed using DNA amplification technology.
Murray, SA, Hoppenrath, M, Orr, RJ, Bolch, C, John, U, Diwan, R, Yauwenas, R, Harwood, T, de Salas, M, Neilan, B & Hallegraeff, G 2014, 'Alexandrium diversaporum sp. nov., a new non-saxitoxin producing species: Phylogeny, morphology and sxtA genes', Harmful Algae, vol. 31, pp. 54-65.View/Download from: Publisher's site
Murray, SA, Momigliano, P, Heimann, K & Blair, D 2014, 'Molecular phylogenetics and morphology of Gambierdiscus yasumotoi from tropical eastern Australia', Harmful Algae, vol. 39, pp. 242-252.View/Download from: Publisher's site
Here the occurrence of the species Gambierdiscus yasumotoi is reported for the first time along a latitudinal gradient spanning more than 1550 km of the Australian Great Barrier Reef (GBR), a region with endemic ciguatera fish poisoning. G. yasumotoi was found at three tropical and sub tropical coral reef sites, Raine Island (northern GBR), Nelly Bay (central GBR) and Heron Island (southern GBR), indicating a wide-ranging distribution in tropical and subtropical eastern Australia. Specimens from Australia broadly fitted the original description of G. yasumotoi, but differed in some aspects, showing some similarities to Gambierdiscus ruetzleri. Molecular phylogenetic analyses based on nuclear rRNA gene sequences and morphological analyses showed specimens to be intermediate between the two species G. yasumotoi and G. ruetzleri. The full intraspecific diversity of these two species appears to be incompletely known, and these two species may represent a species complex. Strains of this species from other sites around the world have been found to produce an as yet unknown toxin, possibly an analogue of maitotoxin.
Watanabe, K, Miyoshi, Y, Kubo, F, Onuma, R, Murray, SA & Horiguchi, T 2014, 'Ankistrodinium armigerum sp. nov. (Dinophyceae), a new species of heterotrophic marine sand-dwelling dinoflagellate from Japan and Australia', Phycological Research, vol. 62, no. 2, pp. 125-135.View/Download from: Publisher's site
A new heterotrophic sand-dwelling dinoflagellate, Ankistrodinium armigerum K. Watanabe, Miyoshi, Kubo, Murray et Horiguchi sp. nov., is described from Ishikari Beach, Hokkaido, Japan and Port Botany, NSW, Australia. The dinoflagellate is laterally compressed, possessing a short triangular epicone and a large sac-like hypocone. It possesses a right-handed cingulum and a deeply-incised sulcus. The sulcus descends towards the posterior of the cell where it becomes much deeper and wider, resulting in a bilobed ventral side to the hypocone, with a greater excavation of the left lobe than the right. In addition, the right lobe of the hypocone is shorter than the left lobe, which allows a partial view of the left sulcal wall when the cell is viewed from its right side. The sulcus ascends in the epicone to form an apical groove. The apical groove is linear but terminates in an ellipsoid fashion and its extremity approaches, but does not form a closed loop with the apical end of the linear portion. The dinoflagellate possesses two distinct size classes of trichocysts. The large trichocysts are located in the posterior part of the cell, while small trichocysts are distributed throughout the cell. The dinoflagellate shares morphological characteristics with the heterotrophic sand-dwelling dinoflagellate, Ankistrodinium semilunatum, the type species of the genus. These include a laterally compressed cell, a right-handed cingulum, a deeply-incised sulcus and the same basic structure to the apical groove. Molecular phylogenetic analyses based on small and large subunits of rDNA showed that in both trees, A. semilunatum and A. armigerum formed a robust clade, suggesting that these two species are closely related. Because no organism with the characteristics of this species exists and because this species is closely related to A. semilunatum, we concluded that this species should be described as a second species of the genus Ankistrodinium.
Wiese, M, Murray, SA, Alvin, A & Neilan, BA 2014, 'Gene expression and molecular evolution of sxtA4 in a saxitoxin producing dinoflagellate Alexandrium catenella', TOXICON, vol. 92, pp. 102-112.View/Download from: Publisher's site
Hoppenrath, M, Chomerat, N, Horiguchi, T, Schweikert, M, Nagahama, Y & Murray, SA 2013, 'Taxonomy and phylogeny of the benthic Prorocentrum species (Dinophyceae) - A proposal and review', Harmful Algae, vol. 27, no. 1, pp. 1-28.View/Download from: Publisher's site
Based on a literature review and new morphological and molecular phylogenetic data, a summary of all described benthic Prorocentrum species is presented. Short descriptions of the 29 species are provided including information and illustrations of platelet pattern. Increasing morphological data of the same taxon from different sites has revealed unexpected morphological variability. The variability of characters used for taxonomy is discussed. Many of these may be more variable than previously thought or phenotypically plastic. We conclude that the following features are constant within a species: (1) asymmetry or symmetry of the theca in combination with (2) the shape of the periflagellar area visible on the right thecal plate, (a) arc-shaped, (b) wide or simply V-shaped, (c) narrow and deep V-shaped, and (d) linear. At the same time, we are now beginning to understand that the cell shape of some species is more variable than thought and not in others. The stability of pore patterns is not known to date nor is it known whether the presence of a starch sheath is a reliable taxonomic character. The morphology of the periflagellar area might be a very useful character. The unstable terminology to describe similar or identical structures has made it difficult to interpret the literature on these features.
Orr, RJ, Stuken, A, Murray, SA & Jakobsen, KS 2013, 'Evolutionary acquisition and loss of saxitoxin biosynthesis in dinoflagellates: the second "core" gene, sxtG', Applied and Environmental Microbiology, vol. 79, no. 7, pp. 2128-2136.View/Download from: Publisher's site
Saxitoxin and its derivatives are potent neurotoxins produced by several cyanobacteria and dinoflagellate species. SxtA is the initial enzyme in the biosynthesis of saxitoxin. The dinoflagellate full mRNA and partial genomic sequences have previously been characterized, and it appears that sxtA originated in dinoflagellates through a horizontal gene transfer from a bacterium. So far, little is known about the remaining genes involved in this pathway in dinoflagellates. Here we characterize sxtG, an amidinotransferase enzyme gene that putatively encodes the second step in saxitoxin biosynthesis. In this study, the entire sxtG transcripts from Alexandrium fundyense CCMP1719 and Alexandrium minutum CCMP113 were amplified and sequenced. The transcripts contained typical dinoflagellate spliced leader sequences and eukaryotic poly(A) tails. In addition, partial sxtG transcript fragments were amplified from four additional Alexandrium species and Gymnodinium catenatum. The phylogenetic inference of dinoflagellate sxtG, congruent with sxtA, revealed a bacterial origin. However, it is not known if sxtG was acquired independently of sxtA. Amplification and sequencing of the corresponding genomic sxtG region revealed noncanonical introns. These introns show a high interspecies and low intraspecies variance, suggesting multiple independent acquisitions and losses. Unlike sxtA, sxtG was also amplified from Alexandrium species not known to synthesize saxitoxin. However, amplification was not observed for 22 non-saxitoxin-producing dinoflagellate species other than those of the genus Alexandrium or G. catenatum. This result strengthens our hypothesis that saxitoxin synthesis has been secondarily lost in conjunction with sxtA for some descendant species.
Orr, RJ, Stüken, A, Murray, SA & Jakobsen, KS 2013, 'Evolution and distribution of saxitoxin biosynthesis in dinoflagellates', Marine Drugs, vol. 11, no. 8, pp. 2814-2828.View/Download from: Publisher's site
Numerous species of marine dinoflagellates synthesize the potent environmental neurotoxic alkaloid, saxitoxin, the agent of the human illness, paralytic shellfish poisoning. In addition, certain freshwater species of cyanobacteria also synthesize the same toxic compound, with the biosynthetic pathway and genes responsible being recently reported. Three theories have been postulated to explain the origin of saxitoxin in dinoflagellates: The production of saxitoxin by co-cultured bacteria rather than the dinoflagellates themselves, convergent evolution within both dinoflagellates and bacteria and horizontal gene transfer between dinoflagellates and bacteria. The discovery of cyanobacterial saxitoxin homologs in dinoflagellates has enabled us for the first time to evaluate these theories. Here, we review the distribution of saxitoxin within the dinoflagellates and our knowledge of its genetic basis to determine the likely evolutionary origins of this potent neurotoxin
Ajani, P, Murray, SA, Hallegraeff, G, Brett, S & Armand, L 2013, 'First reports of Pseudo-nitzschia micropora and P. hasleana (Bacillariaceae) from the Southern Hemisphere: Morphological, molecular and toxicological characterization', Phycological Research, vol. 61, no. 3, pp. 237-248.View/Download from: Publisher's site
Pseudo-nitzschia H. Peragallo is a marine diatom genus found worldwide in polar, temperate, subtropical and tropical waters. It includes toxigenic representatives that produce domoic acid (DA), a neurotoxin responsible for Amnesic Shellfish Poisoning. In this study we characterized two species of Pseudo-nitzschia collected from Port Stephens and the Hawkesbury River (south eastern Australia) previously unreported from Australian waters. Clonal isolates were sub-sampled for (i) light and transmission electron microscopy; (ii) DNA sequencing, based on the nuclear-encoded partial large subunit ribosomal RNA gene and internal transcribed spacer (ITS)-ITS1, 5.8S and ITS2 rDNA regions and, (iii) DA production as measured by liquid chromatography-mass spectrometry. Morphological and molecular data unambiguously revealed the species to be Pseudo-nitzschia micropora Priisholm, Moestrup & Lundholm (Port Stephens) and Pseudo-nitzschia hasleana Lundholm (Hawkesbury River). This is the first report of the occurrence of these species from the Southern Hemisphere and the first report of P.?micropora in warm-temperate waters. Cultures of P.?micropora, tested for DA production for the first time, proved to be non-toxic. Similarly, no detectable toxin concentrations were observed for P.?hasleana. Species resolution and knowledge on the toxicity of local Pseudo-nitzschia species has important implications for harmful algal bloom monitoring and management.
Ajani, P, Murray, SA, Hallegraeff, G, Lundholm, N, Gillings, M, Brett, S & Armand, L 2013, 'The diatom genus Pseudo-nitzschia (Bacillariophyceae) in New South Wales, Australia: morphotaxonomy, molecular phylogeny, toxicity, and distribution', Journal of Phycology, vol. 49, no. 4, pp. 765-785.View/Download from: Publisher's site
Species belonging to the potentially harmful diatom genus Pseudo-nitzschia, isolated from 16 localities (31 sampling events) in the coastal waters of south-eastern Australia, were examined. Clonal isolates were characterized by (i) light and transmission electron microscopy; (ii) phylogenies, based on sequencing of nuclear-encoded ribosomal deoxyribonucleic acid (rDNA) regions and, (iii) domoic acid (DA) production as measured by liquid chromatographymass spectrometry (LC-MS/MS). Ten taxa were unequivocally confirmed as Pseudo-nitzschia americana, P. arenysensis, P. calliantha, P. cuspidata, P. fraudulenta, P. hasleana, P. micropora, P. multiseries, P. multistriata, and P. pungens. An updated taxonomic key for south-eastern Australian Pseudo-nitzschia is presented. The occurrence of two toxigenic species, P. multistriata (maximum concentration 11 pg DA per cell) and P. cuspidata (25.4 pg DA per cell), was documented for the first time in Australia. The Australian strains of P. multiseries, a consistent producer of DA in strains throughout the world, were nontoxic. Data from 5,888 water samples, collected from 31 oyster-growing estuaries (2,000 km coastline) from 2005 to 2009, revealed 310 regulatory exceedances for Total Pseudo-nitzschia, resulting in six toxic episodes. Further examination of high-risk estuaries revealed that the P. seriata group had highest cell densities in the austral summer, autumn, or spring (species dependent), and lowest cell densities in the austral winter, while the P. delicatissima group had highest in winter and spring
Farrell, H, Brett, S, Ajani, P & Murray, SA 2013, 'Distribution of the genus Alexandrium (Halim) and paralytic shellfish toxins along the coastline of New South Wales, Australia', Marine Pollution Bulletin, vol. 72, no. 1, pp. 133-145.View/Download from: Publisher's site
Blooms of Alexandrium species, in particular the species Alexandrium catenella, accounted for more than 50% of algal related, shellfish aquaculture harvest zone closures in New South Wales (NSW) Australia since 2005. While there are indications that species of Alexandrium are more abundant than they were formerly, there is little data available on the spatial and temporal distribution and abundance of the genus in NSW. A six and a half year dataset comprising a total of 8649 fortnightly samples from 31 estuaries spread over 2000 km of NSW coastline was analysed. The greatest abundances of Alexandrium spp. were observed during the austral Spring and Summer, in estuaries in the mid and southern latitudes of the state. In identifying these high risk zones, we propose variables such as season, temperature, rainfall and estuarine flushing to be targeted in intensive site specific studies, to support the development of predictive tools for resource managers.
Glanville, EJ, Murray, SA & Seebacher, F 2012, 'Thermal adaptation in endotherms: climate and phylogeny interact to determine population-level responses in a wild rat', Functional Ecology, vol. 26, no. 2, pp. 390-398.View/Download from: Publisher's site
1. The ecology of endotherms is driven by their great energetic need for thermoregulation, which renders mammals and birds particularly vulnerable to environmental temperature and resource fluctuations. Important outstanding questions are whether populations are specialized to their particular climate, and to what extent gene x environment interactions determine thermal responses. 2. Here, we show that phylogenetic relatedness and climate interact to determine metabolic capacities, body temperature and morphology in a wild rat ( Rattus fuscipes). 3. Mitochondrial metabolic capacities are greater in warm climate populations, indicating that these responses are not the result of cold adaptation. However, glycolytic capacities, fur thickness and capacity for nonshivering thermogenesis are greater in cool climate populations. In populations from cooler climates, body temperatures are lower, but more variable. Together, these changes lead to substantial energy savings in cool climate populations, although all traits are constrained by phylogenetic relatedness. 4. We demonstrate for the first time that gene u environment interactions determine thermal responses in wild mammal populations, and we suggest that physiological variability among populations may render the species more resilient to climate change because it increases wholespecies performance breadth. Climate envelope modelling is therefore insufficient to predict the future impact of climate change.
Hoppenrath, M, Murray, SA, Sparmann, SF & Leander, BS 2012, 'Morphology and molecular phylogeny of Ankistrodinium Gen. Nov (Dinophyceae), a new genus of marine sand-dwelling dinoflagellates formerly classified within Amphidinium', Journal Of Phycology, vol. 48, no. 5, pp. 1143-1152.View/Download from: Publisher's site
The classical athecate dinoflagellate genera (Amphidinium, Gymnodinium, Gyrodinium) have long been recognized to be polyphyletic. Amphidinium sensu lato is the most diverse of all marine benthic dinoflagellate genera; however, following the redefinition
Murray, SA, Garby, T, Hoppenrath, M & Neilan, BA 2012, 'Genetic diversity, morphological uniformity and polyketide production in dinoflagellates (Amphidinium, Dinoflagellata)', Plos One, vol. 7, no. 6, pp. e38253-0.View/Download from: Publisher's site
Dinoflagellates are an intriguing group of eukaryotes, showing many unusual morphological and genetic features. Some groups of dinoflagellates are morphologically highly uniform, despite indications of genetic diversity. The species Amphidinium carterae is abundant and cosmopolitan in marine environments, grows easily in culture, and has therefore been used as a `model dinoflagellate in research into dinoflagellate genetics, polyketide production and photosynthesis. We have investigated the diversity of `cryptic species of Amphidinium that are morphologically similar to A. carterae, including the very similar species Amphidinium massartii, based on light and electron microscopy, two nuclear gene regions (LSU rDNA and ITS rDNA) and one mitochondrial gene region (cytochrome b). We found that six genetically distinct cryptic species (clades) exist within the species A. massartii and four within A. carterae, and that these clades differ from one another in molecular sequences at levels comparable to other dinoflagellate species, genera or even families. Using primers based on an alignment of alveolate ketosynthase sequences, we isolated partial ketosynthase genes from several Amphidinium species. We compared these genes to known dinoflagellate ketosynthase genes and investigated the evolution and diversity of the strains of Amphidinium that produce them.
Murray, SA, Patterson, DJ & Thessen, AE 2012, 'Transcriptomics and microbial eukaryote diversity: a way forward', Trends in Ecology & Evolution, vol. 27, no. 12, pp. 651-652.View/Download from: Publisher's site
Recent reviews have pointed out the large proportion of microbial eukaryotic (protist) diversity that has yet to be described, and the enormous challenges that accompany its description . The ~100 000 species  of microbial eukaryotes may be significantly underestimated if we continue to discover increasing numbers of cryptic species. Tools such as environmental sequencing, which have been highly successful in revealing novel lineages of uncultured bacteria and archaea, promise to add substantial new data for comparatively little effort . In our opinion, significant challenges, grounded in both biology and the history of study of these organisms, need to be faced before environmental sequencing can unlock our understanding of microbial eukaryotic diversity.
Murray, SA, Wiese, M, Neilan, BA, Orr, RJ, de Salas, M, Brett, S & Hallegraeff, G 2012, 'A reinvestigation of saxitoxin production and sxtA in the 'non-toxic' Alexandrium tamarense Group V clade', Harmful Algae, vol. 18, no. 1, pp. 96-104.View/Download from: Publisher's site
The three Alexandrium species A. tamarense, A. fundyense and A. catenella include strains that can be potent producers of the neurotoxin saxitoxin (STX) and its analogues, the causative agents of paralytic shellfish poisoning (PSP). These three species a
Orr, RJ, Murray, SA, Stuken, A, Rhodes, L & Jakobsen, KS 2012, 'When naked became armored: An eight-gene phylogeny reveals monophyletic origin of theca in dinoflagellates', Plos One, vol. 7, no. 11, pp. e50004-0.View/Download from: Publisher's site
The dinoflagellates are a diverse lineage of microbial eukaryotes. Dinoflagellate monophyly and their position within the group Alveolata are well established. However, phylogenetic relationships between dinoflagellate orders remain unresolved. To date, only a limited number of dinoflagellate studies have used a broad taxon sample with more than two concatenated markers. This lack of resolution makes it difficult to determine the evolution of major phenotypic characters such as morphological features or toxin production e.g. saxitoxin. Here we present an improved dinoflagellate phylogeny, based on eight genes, with the broadest taxon sampling to date. Fifty-five sequences for eight phylogenetic markers from nuclear and mitochondrial regions were amplified from 13 species, four orders, and concatenated phylogenetic inferences were conducted with orthologous sequences. Phylogenetic resolution is increased with addition of support for the deepest branches, though can be improved yet further. We show for the first time that the characteristic dinoflagellate thecal plates, cellulosic material that is present within the sub-cuticular alveoli, appears to have had a single origin. In addition, the monophyly of most dinoflagellate orders is confirmed: the Dinophysiales, the Gonyaulacales, the Prorocentrales, the Suessiales, and the Syndiniales. Our improved phylogeny, along with results of PCR to detect the sxtA gene in various lineages, allows us to suggest that this gene was probably acquired separately in Gymnodinium and the common ancestor of Alexandrium and Pyrodinium and subsequently lost in some descendent species of Alexandrium.
Thessen, AE, Patterson, DJ & Murray, SA 2012, 'The taxonomic significance of species that have only been observed once: The genus Gymnodinium (dinoflagellata) as an example', Plos One, vol. 7, no. 8, pp. e44015-0.View/Download from: Publisher's site
Murray, SA, Mihali, TK & Neilan, BA 2011, 'Extraordinary conservation, gene loss, and positive selection in the evolution of an ancient neurotoxin', Molecular Biology And Evolution, vol. 28, no. 3, pp. 1173-1182.View/Download from: Publisher's site
The recent determination of the genetic basis for the biosynthesis of the neurotoxin, saxitoxin, produced by cyanobacteria, has revealed a highly complex sequence of reactions, involving over 30 biosynthetic steps encoded by up to 26 genes clustered at o
Murray, SA, Wiese, M, Stuken, A, Brett, S, Kellmann, R, Hallegraeff, G & Neilan, BA 2011, 'A quantitative molecular assay based on the gene sxtA to identify saxitoxin-producing harmful algal blooms in marine waters', Applied and Environmental Microbiology, vol. 77, no. 19, pp. 7050-7057.View/Download from: Publisher's site
The recent identification of genes involved in the production of the potent neurotoxin and keystone metabolite saxitoxin (STX) in marine eukaryotic phytoplankton has allowed us for the first time to develop molecular genetic methods to investigate the ch
Nagahama, Y, Murray, SA, Tomaru, A & Fukuyo, Y 2011, 'Species boundaries in the toxic dinoflagellate Prorocentrum lima (Dinophyceae, Prorocentrales), based on morphological and phylogenetic characters', Journal of Phycology, vol. 47, no. 1, pp. 178-189.View/Download from: Publisher's site
Wild and cultured specimens of Prorocentrum lima (Ehrenb.) F. Stein from 26 widely different areas in 13 countries were examined in order to determine consistent characters for delimiting species boundaries in this taxon. The morphological characters val
Stuken, A, Orr, RJ, Kellmann, R, Murray, SA, Neilan, BA & Jakobsen, KS 2011, 'Discovery of nuclear-encoded genes for the neurotoxin saxitoxin in dinoflagellates', Plos One, vol. 6, no. 5, pp. e20096-0.View/Download from: Publisher's site
Saxitoxin is a potent neurotoxin that occurs in aquatic environments worldwide. Ingestion of vector species can lead to paralytic shellfish poisoning, a severe human illness that may lead to paralysis and death. In freshwaters, the toxin is produced by p
Weatherby, K, Murray, SA, Carter, D & Slapeta, J 2011, 'Surface and flagella morphology of the motile form of Chromera velia revealed by field-emission scanning electron microscopy', Protist, vol. 162, no. 1, pp. 142-153.View/Download from: Publisher's site
Chromera velia (Chromerida; Alveolata) is an autotrophic protist isolated from stony corals. Ch. velia possesses a chloroplast thought to be most closely related to the apicoplasts of non-photosynthetic apicomplexa. Phylogenetic analyses place Ch. velia as a close relative of parasitic apicomplexa and predatory colpodellids. We have used field-emission scanning electron microscopy of cells sputter-coated with gold or chromium and non-coated cells to characterise the surface ultrastructure of the motile form of Ch. velia. In overall morphology the biflagellated Ch. velia cells resemble the colpodellid Colpodella edax, but with some notable differences. The ventral side of the flagellated Ch. velia cell has two grooves extending from the anterior flagella insertion point with a ridge rising towards the anterior apex of the cell. The anterior flagellum is shorter than the posterior flagellum and possesses a distinct, small curved appendage. The insertion point of the anterior flagellum is partly enclosed by a flap extending from the cell. The posterior flagellum is approximately four times the length of the cell and possesses mastigonemes. The combination of coating techniques proved superior to the commonly used gold coating to determine fine surface ultrastructure. This new ultrastructural information for Ch. velia allowed us to emend its diagnosis.
Kalaitzis, JA, Chau, R, Kohli, GS, Murray, SA & Neilan, BA 2010, 'Biosynthesis of toxic naturally-occurring seafood contaminants', Toxicon, vol. 56, no. 2, pp. 244-258.View/Download from: Publisher's site
Outbreaks of human illness caused by the consumption of contaminated seafood, continues to be a major problem particularly for the shellfish industry. Toxins from marine, brackish and freshwater environments, which are often produced as a result of harmful algal blooms, have been implicated as the causative agents of these poisonings. Commonly, poisoning events have been grouped into one of six classes, Paralytic Shellfish Poisoning (PSP), Diarrhetic Shellfish Poisoning (DSP), Neurotoxic Shellfish Poisoning (NSP), Ciguatera Fish Poisoning (CFP), Azaspiracid Shellfish Poisoning (AZP), and Amnesiac Shellfish Poisoning (ASP). The causative agents of these specific poisonings along with their biosyntheses are discussed in this review. The highly unusual and complex structures of most common seafood toxins have made them interesting targets for biosynthetic studies. Many of the toxins presented are biosynthesized via complex pathways that have been elucidated either through isotope labelled precursor feeding studies and/or characteriza- tion of the genes encoding the producing organisms biosynthetic machinery. Feeding studies key to our understanding of a particular toxins biosynthesis, such as the incor- poration of unusual precursors, as well as unique biosynthetic pathways and rare chemical mechanisms involved in the assembly process are highlighted. More recently, however, modern genomics-based techniques have been used for the elucidation of biosynthetic pathways and these are presented in the context of polyketide, non-ribosomal peptide, and hybrid pathway derived, toxin assembly.
Murray, SA, Ip, CL, Moore, R, Nagahama, Y & Fukuyo, Y 2009, 'Are prorocentroid dinoflagellates monophyletic? A study of 25 species based on nuclear and mitochondrial genes', Protist, vol. 160, no. 2, pp. 245-264.View/Download from: Publisher's site
The dinoflagellate sub-class Prorocentrophycidae has a distinct morphology, lacking the typical dinoflagellate cell structure of a clear cingulum and sulcus. It includes species that produce the toxin okadaic acid. Despite its uniqueness, the group has been found polyphyletic in some previous molecular phylogenetic studies. We have re-investigated the phylogeny of this sub-class by culturing and sequencing new strains, comparing sequences from three genes, the mitochondrial cytochrome c oxidase subunit 1 ( cox 1) and the nuclear large and small subunit rRNA (LSU and SSU) encoding genes. We analyzed sequences from twenty-five named and two still undescribed species of Prorocentrophycidae. We used newly recognized features of the secondary structure to align regions of the LSU rRNA. The phylogeny based on cox 1 provided the most well-supported tree and showed strong support for the monophyly of prorocentroid dinoflagellates, while the LSU phylogeny was inconclusive. As in previous studies, phylogeny based on SSU shows the group to appear paraphyletic, however, support values were low. Two strongly supported sub-clades were consistently identified. Benthic and planktonic modes appear to have evolved on multiple occasions within both clades of Prorocentriphycidae. The capability to synthesize toxins appears to have arisen early in prorocentroid evolution and, in particular, okadaic acid synthesis is present in some, but not all, members of Clade 2. The D2a region of the LSU rRNA appears to have developed a deletion in three definable steps during prorocentroid evolution. While the phylogenies inferred from the three genes were not congruent, our results give reserved support to the monophyly of the group.
Murray, SA, O'Connor, WA, Alvin, A, Mihali, TK, Kalaitzis, J & Neilan, BA 2009, 'Differential accumulation of paralytic shellfish toxins from Alexandrium minutum in the pearl oyster, Pinctada imbricata', Toxicon, vol. 54, no. 3, pp. 217-223.View/Download from: Publisher's site
To investigate the potential for differential accumulation of paralytic shellfish toxins (PSTs) in various tissues of the akoya pearl oyster, Pinctada imbricata, two feeding trials were carried out using the PST-producing dinoflagellate, Alexandrium minu
Seebacher, F, Murray, SA & Else, PL 2009, 'Thermal acclimation and regulation of metabolism in a reptile (Crocodylus porosus): the importance of transcriptional mechanisms and membrane composition', Physiological and Biochemical Zoology, vol. 82, no. 6, pp. 766-775.View/Download from: Publisher's site
Energy metabolism is fundamental for animal fitness because it fuels locomotion, growth, and reproduction. Mitochondrial capacities often acclimate to compensate for negative thermodynamic effects. Our aim was to determine the importance of transcriptional regulation and membrane fatty acid composition in modulating oxidative capacities at body temperatures selected in a cold and a warm environment by a reptile (Crocodylus porosus). In the cool environment (mean selected T(b) = 21 degrees C), mRNA concentrations of the transcription factor peroxisome proliferator-activated receptor gamma (PPAR gamma) and its coactivator PPAR gamma coactivator 1 alpha (PGC-1 alpha), as well as of the cytochrome c oxidase (COX) subunits COX1 and COX5, were significantly higher in the liver but not in skeletal muscle compared with animals in the warm environment (mean selected T(b) = 29 degrees C). F(O)F(1)-ATPase subunit alpha mRNA concentrations were significantly higher in both muscle and the liver in the cool animals. A positive relationship between PGC-1 alpha and PPAR gamma mRNA concentrations, with an indicator of mitochondrial density (16S rRNA) in muscle and COX and F(O)F(1)-ATPase subunit alpha mRNA concentrations in liver, suggest that these proteins regulate quantity increases of mitochondria during acclimation. The percent saturated fatty acids in liver membranes of cool animals was significantly lower, and the n3 fatty acid content was significantly higher, compared with in warm animals. The n3 fatty acid content was positively related to COX enzyme activity in the liver, and there was a negative relationship between n7 fatty acid content and COX activity in muscle. Hence, metabolic acclimation is mediated by both transcriptional regulation and membrane fatty acid composition. The importance of PGC-1 alpha and PPAR gamma in a reptile indicate that the mechanisms that regulate metabolism are conserved among vertebrates.
Schwartz, TS, Murray, SA & Seebacher, F 2008, 'Novel reptilian uncoupling proteins: molecular evolution and gene expression during cold acclimation', Proceedings of the Royal Society of London Series B-Biological Sciences, vol. 275, no. 1637, pp. 979-985.View/Download from: Publisher's site
Many animals upregulate metabolism in response to cold. Uncoupling proteins (UCPs) increase proton conductance across the mitochondrial membrane and can thereby alleviate damage from reactive oxygen species that may form as a result of metabolic upregulation. Our aim in this study was to determine whether reptiles (Crocodylus porosus) possess UCP genes. If so, we aimed to place reptilian UCP genes within a phylogenetic context and to determine whether the expression of UCP genes is increased during cold acclimation. We provide the first evidence that UCP2 and UCP3 genes are present in reptiles. Unlike in other vertebrates, UCP2 and UPC3 are expressed in liver and skeletal muscle of the crocodile, and both are upregulated in liver during cold acclimation but not in muscle. We identified two transcripts of UCP3, one of which produces a truncated protein similar to the UCP3S transcript in humans, and the resulting protein lacks the predicted nucleotide-binding regulatory domain. Our molecular phylogeny suggests that uncoupling protein 1 (UCP1) is ancestral and has been lost in archosaurs. In birds, UCP3 may have assumed a similar function as UCP1 in mammals, which has important ramifications for understanding endothermic heat production.
Gilbert, PM, Azanza, R, Burford, MA, Furuya, K, Abal, E, Al-Azri, A, Al-Yamani, F, Andersen, P, Anderson, DM, Beardall, J, Berg, GM, Brand, L, Bronk, D, Brookes, J, Burkholder, JM, Cembella, A, Cochlan, WP, Collier, JL, Collos, Y, Diaz, R, Doblin, MA, Drennen, T, Dyhrman, S, Fukuyo, Y, Furnas, M, Galloway, J, Graneli, E, Ha, D, Hallegraeff, GM, Harrison, J, Harrison, P, Heil, CA, Heimann, K, Howarth, R, Jauzein, M, Kana, AA, Kana, TM, Kim, H, Kudela, R, Legrand, C, Mallin, M, Mulholland, M, Murray, SA, O'Neil, J, Pitcher, G, Qi, Y, Rabalais, N, Raine, R, Seitzinger, S, Salomon, PS, Solomon, C, Stoecker, DK, Usup, G, Wilson, J, Yin, K, Zhou, M & Zhu, M 2008, 'Ocean urea fertilization for carbon credits poses high ecological risks', Marine Pollution Bulletin, vol. 56, no. 6, pp. 1049-1056.View/Download from: Publisher's site
The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed. Â© 2008 Elsevier Ltd. All rights reserved.
Murray, SA, de Salas, M, Luong-Van, J & Hallegraeff, G 2007, 'Phylogenetic study of Gymnodinium dorsalisulcum comb. nov. from tropical Australian coastal waters (Dinophyceae)', Phycological Research, vol. 55, no. 2, pp. 176-184.
Murray, SA, Nagahama, Y & Fukuyo, Y 2007, 'Phylogenetic study of benthic, spine-bearing prorocentroids, including Prorocentrum fukuyoi sp. nov.', Phycological Research, vol. 55, pp. 91-102.
Seebacher, F & Murray, SA 2007, 'Transient receptor potential ion channels control thermoregulatory behaviour in reptiles', PLoS One, vol. 3, p. e281.
Murray, SA, Hoppenrath, M, Larsen, J & Patterson, DJ 2006, 'Bysmatrum teres sp. nov., a new sand-dwelling dinoflagellate from north-western Australia', Phycologia, vol. 45, no. 2, pp. 161-167.View/Download from: Publisher's site
Murray, SA, Hoppenrath, M, Preisfeld, A, Larsen, J, Yoshimatsu, S, Toriumi, S & Patterson, DJ 2006, 'Phylogenetics of Rhinodinium broomeense gen. et sp. nov., a peridinoid, sand-dwelling dinoflagellate (Dinophyceae)', Journal of Phycology, vol. 42, pp. 934-942.View/Download from: Publisher's site
Murray, SA, Jorgensen, MF, Ho, SY, Patterson, DJ & Jermiin, LS 2005, 'Improving the analysis of dinoflagellate phylogeny based on rDNA', Protist, vol. 156, pp. 269-286.View/Download from: Publisher's site
Jorgensen, MF, Murray, S & Daugbjerg, N 2004, 'Amphidinium revisited. I. Redefinition of Amphidinium (Dinophyceae) based on cladistic and molecular phylogenetic analyses (vol 40, pg 351, 2004)', JOURNAL OF PHYCOLOGY, vol. 40, no. 6, pp. 1181-1181.View/Download from: Publisher's site
Jorgensen, MF, Murray, SA & Daugbjerg, N 2004, 'A new genus of athecate interstitial dinoflagellates, Togula gen. nov., previously encompassed within Amphidinium sensu lato: Inferred from light and electron microscopy and phylogenetic analyses of partial large subunit ribosomal DNA sequences', Phycological Research, vol. 52, no. 3, pp. 284-299.
Jorgensen, MF, Murray, SA & Daugbjerg, N 2004, 'Amphidinium revisited. I. Redefinition of Amphidinium (Dinophyceae) based on cladistic and molecular phylogenetic analyses', Journal of Phycology, vol. 40, pp. 351-365.View/Download from: Publisher's site
Lenzen, M, Dey, CJ & Murray, SA 2004, 'Historical accountability and cumulative impacts: the treatment of time in corporate sustainability reporting', Ecological Economics, vol. 51, no. 3-4, pp. 237-250.View/Download from: Publisher's site
Murray, SA & Patterson, DJ 2004, 'Cabra matta, gen. nov., sp. nov., a new benthic, heterotrophic dinoflagellate', European Journal of Phycology, vol. 39, pp. 229-234.View/Download from: Publisher's site
Murray, SA, Jorgensen, MF, Daugbjerg, N & Rhodes, L 2004, 'Amphidinium revisited. II. Resolving species boundaries in the Amphidinium operculatum species complex (Dinophyceae), including the descriptions of Amphidinium trulla sp. nov. and Amphidinium gibbosum comb. nov.', Journal of Phycology, vol. 40, pp. 366-382.View/Download from: Publisher's site
Lenzen, M, Murray, SA, Korte, B & Dey, CJ 2003, 'Environmental impact assessment including indirect effects - a case study using input - output analysis', Environmental Impact Assessment Review, vol. 23, pp. 263-282.
Al-Qassab, S, Lee, WJ, Murray, SA, Simp, AG & Patterson, DJ 2002, 'Flagellates from stromatolites and surrounding sediments in Shark Bay, Western Australia', Acta Protozoologica, vol. 41, pp. 91-144.
Murray, SA & Patterson, DJ 2002, 'The benthic dinoflagellate genus Amphidinium in south-eastern Australian waters, including three new species', European Journal of Phycology, vol. 37, pp. 279-298.View/Download from: Publisher's site
Murray, SA & Suthers, I 1999, 'Population ecology of Noctiluca scintillans Macartney, a red-tide-forming dinoflagellate', Marine and Freshwater Research, vol. 50, pp. 243-252.View/Download from: Publisher's site
The population ecology of the large heterotrophic dinoflagellate Noctiluca scintillans Macartney was examined in the coastal ocean and two estuaries in south-eastern Australia from July 1996 to June 1997. High concentrations (>100 cells LÂ1) occurred in spring and again in late summer, and low concentrations (<5 cells LÂ1) in mid summer and mid winter. Abundances were greater in coastal waters than in the estuaries during all months in which concentration exceeded 1 cell LÂ1. During the spring bloom, Noctiluca cells from coastal stations had small diameters (340Â450 mm), a high nutritional status and a high proportion of division stages, indicative of good condition. During the late summer blooms, poor-condition cells were found in coastal waters and especially in the near-surface concentrations of red tides (>104 cells LÂ1), and were characterized by large diameters (400Â1200 mm), cell lysis and uniformly low nutritional status; at this time, Noctiluca cells from estuaries were generally fewer, smaller and in better condition. Overall, cell concentrations were higher in coastal waters than in the estuaries, and red tides of Noctiluca probably developed along the local coast (in spring) or were advected into the area from northern regions (in late summer).
Murray, SA & Hallegraeff, G 2018, 'Harmful Algae Introductions: Vectors of Transfer, Mitigation, and Management' in Shumway, S, Burkholder, JA & Morton, S (eds), Harmful Algal Blooms A Compendium Desk Reference, John Wiley & Sons, USA, pp. 493-506.View/Download from: Publisher's site
Sophisticated molecular tools are now available to identify new introductions and range expansions, or the new blooming of previously unnoticed cryptic species of harmful algae. With the growing awareness of the problem of introduced marine pests in the past 30 years, a number of national and international regulations have been developed to reduce the risk of transfer of nonindigenous organisms. Determining whether a phytoplankton species has invasive characteristics is important for developing policy, management, and research responses to species with harmful impacts. While prediction of the impact of global climate change on marine harmful algal bloom (HAB) is fraught with difficulties, range expansion of warm‐water species at the expense of cold‐water species that are driven poleward is expected. Extensively researched ballast water treatment technologies serve as a guide toward suitable emergency treatment technologies to curb unwanted HAB translocations.
Kohli, GS, Farrell, H & Murray, SA 2015, 'Gambierdiscus, the cause of ciguatera fish poisoning: a review of progress in ecology and toxicology' in Luis Botana, Natalia.Vilarino (ed), Climate change and marine and freshwater toxins, Walter de Gruyter, Germany, pp. 273-312.
Murray, SA, Uwe, J & Kremp, A 2015, 'Alexandrium spp.: genetic and ecological factors influencing saxitoxin production and proliferation' in Botana, LM, Louzao, MC & Vilarino, N (eds), Climate Change and Marine and Freshwater Toxins, Walter de Gruyter, Germany, pp. 125-154.
Neilan, BA, Murray, SA & Chen, M 2010, 'Genomic contributions to understanding the evolution of red algal plastids and pigment biosynthesis' in Seckbach, J & Chapman, DJ (eds), Red algae in the genomic age, Springer, Netherlands, pp. 261-273.
Murray, SA 2007, 'Phylogenetics, molecular biology and ecological impacts of a group of highly unusual protists' in Seckbach, J (ed), Algae and Cyanobacteria in Extreme Environments, Springer, Netherlands, pp. 125-140.
Kohli, GS, Farrell, H & Murray, SA, '9. Gambierdiscus, the cause of ciguatera fish poisoning: an increased human health threat influenced by climate change' in Climate Change and Marine and Freshwater Toxins, DE GRUYTER.View/Download from: Publisher's site
Murray, S, Verma, A, Barua, A, Ruvindy, R, Savela, H & Kohli, G 2019, 'The molecular ecology and evolution of toxin synthesis in marine microbial eukaryotes', Genetics Society of Australasia, Melbourne.
Murray, S, Verma, A, Palanisami, S & Ajani, P 2019, 'The use of eDNA and arrays for precise estuarine water quality assessment', 3rd Australian and New Zealand Marine Biotechnology Society Conference, Sydney, Australia.
Verma, A, Palanisami, S, Ajani, P & Murray, S 2019, 'Novel molecular ecology tools to predict harmful algal blooms in oyster- producing estuaries', Australian Marine Science Association Conference, Freemantle, Australia.
Ajani, P, Farrell, H, Hallegraeff, G, Helleren, S, Lamb, P, Turnbull, A, Zammit, A & Murray, S 2019, 'Diarrhetic Shellfish Toxins in Australian Shellfish', Australian Shellfish Quality Assurance Advisory Committee's National Shellfish Symposium, Perth, WA.
Murray, S, Verma, A, Ajani, P, Zammit, A, Farrell, H, Palanisami, S & O'Connor, W 2018, 'Building profitability and sustainability in the NSW oyster industry (Oral Presentation)', Australian Shellfish Quality Assurance Advisory Committee Science Day, UTS.
Ajani, P, Larsson, M, Rubio, A, Bush, S, Brett, S, Woodcock, S, Farrell, H & Murray, S 2018, 'Modelling harmful algal blooms in the Hawkesbury River, Australia (Oral Presentation)', Australian Shellfish Quality Assurance Advisory Committee Science Day, UTS.
Ajani, PA, Larsson, M, Rubio, A, Bush, S, Brett, S, Woodcock, S, Farrell, H & Murray, S 2018, 'Modelling harmful algal blooms in the Hawkesbury River, Australia (Oral Presentation)', Estuarine and Coastal Science Association Conference, Perth, WA.
Coade, P, Rubio, A, Ajani, PA & Murray, S 2018, 'Local government requirements for managing estuarine algal blooms (Oral Presentation).', Estuarine and Coastal Science Association Conference (ESCA57), Perth, WA.
Farrell, H, Webster, G, Baker, P, Zammit, A, Ajani, PA, Murray, S & Brett, S 2018, 'Developing phytoplankton and biotoxin risk assessments for both shellfish aquaculture and wild harvest shellfish in New South Wales (Oral Presentation)', Australian Shellfish Quality Assurance Advisory Committee Science Day, UTS.
Verma, A, Kohli, G, Hoppenrath, M, Harwood, T, Kuzhiumparambil, U, Ralph, P & Murray, S 2016, 'Systematics and diversity of the genus Ostreopsis in the East Australian Current region', Marine and Fresh-Water Harmful Algae. Proceedings of the 17th International Conference on Harmful Algae., International Conference on Harmful Algae, International Society for Study of Harmful Algae, Brazil, pp. 84-88.
Hallegraeff, G, Bolch, C, Condie, S, Dorantes-Aranda, J, Murray, SA, Quinlan, R, Ruvindy, R, Turnbull, A, Ugalde, S & Wilson, K 2016, 'Unprecedented Alexandrium blooms in a previously low biotoxin risk area of Tasmania, Australia.', Proceedings of the 17th International Conference on Harmful Algae, 17th International Conference on Harmful Algae, ICHA, Brazil, pp. 38-41.
During October 2012, a shipment of blue mussels (Mytilus galloprovincialis) from the poorly monitored east coast of Tasmania, Australia, was tested by Japanese import authorities and found to be contaminated with unacceptable levels of Paralytic Shellfish Toxins (PSTs; 10 mg/kg). Subsequently local oysters, scallops, clams, the viscera of abalone and rock lobsters were also found to be contaminated. This led to a global product recall and loss to the local economy of AUD 23M. Following low toxicity during 2013 and 2014 and implementation of minimal shellfish farm closures, a more severe bloom event occurred during July-November 2015 and again June-September 2016 (up to 300,000 Alexandrium cells/L; 24 mg/kg PST in mussels, 6 mg/kg in Crassostrea gigas oysters), also causing 4 human illnesses resulting in hospitalization after consumption of wild shellfish. While Alexandrium tamarense had been detected in low concentrations in southeastern Australia since 1987, all cultured strains belonged to the mostly non-toxic group 5 (now designated A. australiense; detected since 1987) and weakly toxic group 4 (A. pacificum; detected in 1997).
In contrast, the 2012 to 2016 outbreaks were dominated by highly toxic group 1 (A. fundyense) never
detected previously in the Australian region. Molecular analyses suggest that A. fundyense may have been a cryptic ribotype previously present in Tasmania, but newly stimulated by altered water column stratification
conditions driven by changing rainfall and temperature patterns. Increased seafood and plankton monitoring of the area now include the implementation of Alexandrium qPCR, routine Neogen™ immunological and HPLC PST tests, but ultimately may also drive change in harvesting strategies and aquaculture species selection by the local seafood industry.
Ajani, PA, Hallegraeff, GM, Allen, D, Coughlan, A, Richardson, AJ, Armand, L, Ingleton, I & Murray, SA 2017, 'Establishing baselines: eighty years of phytoplankton diversity and biomass in south-eastern Australia (Oral Presentation). ALSO Aquatic Science Meeting 2017, Hawaii'.
Kim, JH, Wang, P, Park, BS, Kim, J, Patidar, SK, Ajani, PA, Murray, SA, Lim, HC, Lim, PT & Han, M 2017, 'Revealing the hybrid zone and genetic polymorphisms of genetic sub-populations within Pseudo-nitzschia pungens the cosmopolitan diatom species (Oral Presentation). 10th EASTHAB Symposium, Harmful Algal Blooms in East Asia, Dec 2017, Hokkaido, Japan'.
Kim, JH, Wang, P, Park, BS, Paditar, KS, Ajani, PA, Murray, SA, Lim, HC & Lim, PT 2017, 'Revealing the hybrid zone and genetic polymorphisms of genetic sub-populations within Pseudo-nitzschia pungens the cosmopolitan diatom species (Oral Presentation). H-HABs Working Group, 3rd Symposium, Nov 2017, Korea Institute of Ocean Science & Technology, South Korea'.
Murray, SA, Orr, R & John, U 2014, 'Can evolutionary ecology help us to design better biotoxin detection tools? The case of Alexandrium.', Marine and Freshwater Algae, International Conference on Harmful Algae, Cawthron Institute, Wellington, New Zealand, pp. 30-33.
An increase in the occurrence, frequency and severity of blooms of paralytic shellfish toxin (PST) producing
Alexandrium species over the past 30 years has been reported from many parts of the world. PSTs impact
disparate groups of marine organisms and can even structure ecosystems, leading to them being considered
‗keystone metabolites'. There have been many hypotheses as to the role of PSTs for Alexandrium species: of
these, a role as defensive compounds against copepod predation has been generally supported. This
hypothesis would suggest that predation might have acted as a selective force in the evolution of toxicity in
the genus. A study of the evolution and phylogeny of Alexandrium and the A1 and A4 domains of the sxtA
gene , and sxtG gene can be used to investigate such selection. The information on genes related to saxitoxin
synthesis in dinoflagellates can be applied to the design of rapid detection tools for marine biotoxin
monitoring. Such tools have been shown to be useful in the quantification of blooms of Alexandrium species
producing PSTs from Australian and New Zealand
Ajani, P, Murray, S, Hallegraeff, G, Brett, S, Webster, G & Armand, L 2013, 'Identification and seasonal occurrence of potentially toxic Pseudo-nitzschia diatoms in oyster growing estuaries of New South Wales, Australia', Proc. 9th Int. Conf. Molluscan Shellfish Safety, International Conference of Molluscan Shellfish Safety, United Nations FAO, Sydney Australia, pp. 100-103.
Abstract: Species belonging to the potentially toxic diatom genus Pseudo-nitzschia are a significant component of the phytoplankton community in south-east Australian waters. Toxigenic representatives of this genus produce domoic acid and are responsible for the majority of regulatory exceedances in New South Wales (NSW) oyster-growing estuaries. This toxic genus has been implicated in 6 toxic events during the sampling period 2005-2009 (max. concentration of 34 mg DA kg-1 oyster tissue). However, identification to species level is difficult and requires both electron microscopy and molecular techniques for unambiguous identification. Detailed analyses revealed 10 different species in NSW coastal waters, Pseudo-nitzschia americana, P. arenysensis, P. calliantha, P. cuspidata, P. fraudulenta, P. hasleana, P. micropora, P. multiseries, P. multistriata and P. pungens, including two confirmed domoic acid producers, P. cuspidata (25.4 pg DA cell-1) and P. multistriata (11 pg DA cell-1). Species diversity and the seasonal occurrence of regulatory Pseudo-nitzschia groupings have important implications for monitoring and management of shellfish harvest areas in NSW. The ubiquitous species, Pseudo-nitzschia cuspidata, represents the greatest challenge for coastal shellfish culture in NSW
Farrell, H, Ajani, P, Brett, S, Zammit, A & Murray, S 2013, 'Alexandrium species in New South Wales (NSW) coastal waters: historical distributions and identification of high-risk zones', Proc. 9th Int. Conf. Molluscan Shellfish Safety, International Conference on Molluscan Shellfish Safety, United Nations FAO, Sydney Australia, pp. 107-110.
Accumulation of paralytic shellfish poisoning (PSP) toxins, produced by marine planktonic dinoflagellates, can occur in all major commercial shellfish species. Aside from the potential risk to human health, aquaculture industries have reported severe economic losses due to regulatory closures. Members of the dinoflagellate genus Alexandrium are known PSP producers. Since 2005, there has been an apparent increase in reports of Alexandrium blooms in New South Wales (NSW), with species causing over 50% of algal related shellfish harvest zone closures. Our current knowledge of the distribution of the species in NSW is examined with an emphasis on high-risk zones.
Murray, SA, Wiese, M, Stuken, A, Kellmann, R, Brett, S, Hallegraef, GM & Neilan, BA 2011, 'Quantitative assessment of coastal harmful algal blooms based on the saxitoxin biosynthesis gene, sxtA', Gordon Conference on Phycotoxins and Mycotoxins, Boston, United States.
Farrell, H, Ajani, P, Murray, S, Baker, P, Webster, G, Brett, S, Barua, A, Zammit, A & Hill, D CSIRO 2020, Time series of harmful algal blooms in New South Wales, Integrated Marine Observing System, State and Trends of Australia's Oceans Report, Tasmania, Australia.View/Download from: Publisher's site
Ajani, P, Murray, S & Ruvindy, R University of Technology Sydney 2019, Community Composition Assessment in Northern Beaches Lagoons 2018-2019. A report to Northern Beaches Council, September 2019., pp. 1-30, Sydney, Australia.
Murray, SA, Kohli, GS, Harwood, DT, Laczka, O & Boulter, M Fisheries Research and Development Corporation 2016, Safeguarding seafood consumers in NSW from ciguatera fish poisoning, no. ISBN 978-0-646-95465-3, pp. 1-51, Canberra, ACT, Australia.
- Diagnostic Technology
- NSW Department of Primary Industries (Food Authority)
- Sydney Fish Market
- NSW Department of Primary Industries (Fisheries)
- The Yield Pty Ltd
- Northern Beaches Council
- Hornsby Council
- University of Tasmania
- University of Queensland
- Cawthron Institute (New Zealand)
- Senckenberg Institute (Germany)
- Alfred Wegener Institute for Polar and Marine Research (Germany)