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 Plant Functional Biology and 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.
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
Can supervise: YES
Competitive Research Funding Awarded:
Summary: $4.4 M since 2003 (award of PhD); $3.1 M as UTS employee (3.5 years), 80% Category 1 grants
Australian Research Council: 8 ARC Grants since 2007 (2 Linkage, Equipment and Infrastructure (LIEF); 2 Discovery Projects; 3 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) Japan Society for the Promotion of Science.
International patent application (WO/2012/155202) – Detection of saxitoxin-producing dinoflagellates
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, G.M., Bolch, C.J., Hill, D.R., Jameson, I., LeRoi, J., McMinn, A., Murray, S.A., de Salas, F. & Saunders, K. 2010, Algae of Australia: Phytoplankton of temperate coastal waters, 1, CSIRO Publishing, Canberra.
Murray, S.A. 2009, Diversity and phylogenetics of sand-dwelling dinoflagellates, 1, VDM Verlag, Germany.
Larsson, M.E., Laczka, O.F., Harwood, D.T., Lewis, R.J., Himaya, S.W.A., Murray, S.A. & Doblin, M.A. 2018, 'Toxicology of Gambierdiscus spp. (Dinophyceae) from Tropical and Temperate Australian Waters.', Marine drugs, vol. 16, no. 1.View/Download from: UTS OPUS or 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.
Ajani, P.A., Verma, A., Lassudrie, M., Doblin, M.A. & Murray, S.A. 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, p. 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.
Ajani, P.A., Harwood, D.T. & murray, S.A. 2017, 'Recent trends in marine phycotoxins from Australian coastal waters', Marine Drugs.
Ajani, P.A., Harwood, D.T. & murray, S.A. 2017, 'Recent trends in marine phycotoxins from Australian coastal waters', Marine Drugs.
Dorantes-Aranda, J.J., Campbell, K., Bradbury, A., Elliott, C.T., Harwood, D.T., Murray, S.A., Ugalde, S.C., Wilson, K., Burgoyne, M. & Hallegraeff, G.M. 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: UTS OPUS or 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, G.S., Campbell, K., John, U., Smith, K.F., Fraga, S., Rhodes, L.L. & Murray, S.A. 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: UTS OPUS or 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, G.S., Haslauer, K., Sarowar, C., Kretzschmar, A.L., Boulter, M., Harwood, D.T., Laczka, O. & Murray, S.A. 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: UTS OPUS or 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 g kg-1 to <0.1 g kg-1 in flesh, and 1.39 g kg-1 to <0.4 g 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, D.T., 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: UTS OPUS or Publisher's site
© 2016 Elsevier Ltd Paralytic shellfish toxins (PST) were detected in abalone (Haliotis rubra) in April 2011 in south-east Tasmania, Australia, during a dinoflagellate bloom of Gymnodinium catenatum. This led to restrictions on abalone harvesting and triggered continued PST monitoring by Ultra Performance Liquid Chromatography (UPLC-FLD) of abalone and mussels (Mytilus galloprovincialis), and concurrent phytoplankton monitoring, between 2011 and 2013. PST up to 2437 g STX eq kg1(three times the bivalve regulatory limit) were confirmed in abalone viscera, with toxicity up to 586 g STX eq kg1in the muscular foot (mainly doSTX and minor proportions of STX and dcSTX). Mussels accumulated PST at a faster rate than abalone which suggests they can serve as sentinels of PST accumulation to inform abalone risk management protocols. Three lines of evidence for G. catenatum as the source of PST in abalone were established: (1) PST in abalone tissues increased and declined in association with dinoflagellate blooms; (2) G. catenatum DNA was detected by real-time PCR in abalone digestive tracts; and (3) the PST analogues (toxin profile) observed in both abalone viscera and mussels were similar suggesting a common PST source. This is the first time a conclusive linkage between the occurrence of PST in abalone and a dinoflagellate source has been demonstrated.
Smith, K.F., Kohli, G.S., Murray, S.A. & Rhodes, L.L. 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: UTS OPUS or 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, F.M., Kohli, G.S., Morey, J.S. & Murray, S.A. 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: UTS OPUS or Publisher's site
Dinoflagellates are prolific producers of polyketide compounds, many of which are potent toxins with adverse impacts on human and marine animal health. To identify polyketide synthase (PKS) genes in the brevetoxin-producing dinoflagellate, Karenia brevis, we assembled a transcriptome from 595 million Illumina reads, sampled under different growth conditions. The assembly included 125,687 transcripts greater than 300 nt in length, with over half having >100 coverage. We found 121 transcripts encoding Type I ketosynthase (KS) domains, of which 99 encoded single KS domains, while 22 contained multiple KS domains arranged in 1-3 protein modules. Phylogenetic analysis placed all single domain and a majority of multidomain KSs within a monophyletic clade of protist PKSs. In contrast with the highly amplified single-domain KSs, only eight single-domain ketoreductase transcripts were found in the assembly, suggesting that they are more evolutionarily conserved. The multidomain PKSs were dominated by trans-acyltransferase architectures, which were recently shown to be prevalent in other algal protists. Karenia brevis also expressed several hybrid nonribosomal peptide synthetase (NRPS)/PKS sequences, including a burA-like sequence previously reported in a wide variety of dinoflagellates. This contrasts with a similarly deep transcriptome of Gambierdiscus polynesiensis, which lacked NRPS/PKS other than the burA-like transcript, and may reflect the presence of amide-containing polyketides in K. brevis and their absence from G. polynesiensis. In concert with other recent transcriptome analyses, this study provides evidence for both single domain and multidomain PKSs in the synthesis of polyketide compounds in dinoflagellates.
Kretzschmar, A.L., 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: UTS OPUS or 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, S.A., Ajani, P., Kretzschmar, A.L. & 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: UTS OPUS or Publisher's site
Rhodes, L., Smith, K.F., Verma, A., Curley, B.G., Harwood, D.T., Murray, S., Kohli, G.S., Solomona, D., Rongo, T., Munday, R. & Murray, S.A. 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: UTS OPUS or 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.
Davies, C.H., 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, S.C., Lønborg, C., McLaughlin, J., McEnnulty, F., McKinnon, A.D., Miller, M., Murray, S., Nayar, S., Patten, R., Pritchard, T., Proctor, R., Purcell-Meyerink, D., Raes, E., Rissik, D., Ruszczyk, J., Slotwinski, A., Swadling, K.M., Tattersall, K., Thompson, P., Thomson, P., Tonks, M., Trull, T.W., Uribe-Palomino, J., Waite, A.M., Yauwenas, R., Zammit, A. & Richardson, A.J. 2016, 'Corrigendum: A database of marine phytoplankton abundance, biomass and species composition in Australian waters.', Sci Data, vol. 3, p. 160111.View/Download from: UTS OPUS or Publisher's site
Farrell, H., O'Connor, W., Seebacher, F., Harwood, D.T. & 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, G.S., John, U., Van Dolah, F.M. & Murray, S.A. 2016, 'Evolutionary distinctiveness of fatty acid and polyketide synthesis in eukaryotes', ISME JOURNAL, vol. 10, no. 8, pp. 1877-1890.View/Download from: UTS OPUS or Publisher's site
Ajani, P.A., 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: UTS OPUS or 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 day1) under relatively high temperatures (25°C) and light conditions (100µmol photons m2s1) between days 2 and 7 of the experiment. When temperature and light regimes were reduced (18°C, 50µmol photons m2s1) 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, P.A., Kim, J.H., Han, M.S. & Murray, S.A. 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: UTS OPUS or Publisher's site
Davies, C.H., 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, S.C., Lønborg, C., McLaughlin, J., McEnnulty, F., McKinnon, A.D., Miller, M., Murray, S., Nayar, S., Patten, R., Pausina, S.A., Pritchard, T., Proctor, R., Purcell-Meyerink, D., Raes, E., Rissik, D., Ruszczyk, J., Slotwinski, A., Swadling, K.M., Tattersall, K., Thompson, P., Thomson, P., Tonks, M., Trull, T.W., Uribe-Palomino, J., Waite, A.M., Yauwenas, R., Zammit, A. & Richardson, A.J. 2016, 'A database of marine phytoplankton abundance, biomass and species composition in Australian waters.', Scientific data, vol. 3, p. 160043.View/Download from: UTS OPUS or Publisher's site
There have been many individual phytoplankton datasets collected across Australia since the mid 1900s, but most are unavailable to the research community. We have searched archives, contacted researchers, and scanned the primary and grey literature to collate 3,621,847 records of marine phytoplankton species from Australian waters from 1844 to the present. Many of these are small datasets collected for local questions, but combined they provide over 170 years of data on phytoplankton communities in Australian waters. Units and taxonomy have been standardised, obviously erroneous data removed, and all metadata included. We have lodged this dataset with the Australian Ocean Data Network (http://portal.aodn.org.au/) allowing public access. The Australian Phytoplankton Database will be invaluable for global change studies, as it allows analysis of ecological indicators of climate change and eutrophication (e.g., changes in distribution; diatom:dinoflagellate ratios). In addition, the standardised conversion of abundance records to biomass provides modellers with quantifiable data to initialise and validate ecosystem models of lower marine trophic levels.
Murray, S.A., Suggett, D.J., Seymour, J.R., Doblin, M., Kohli, G.S., Fabris, M. & Ralph, P.J. 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: UTS OPUS or 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.
Murray, S.A., Smith, K., Rhodes, L., Verma, A., Curley, B., Harwood, D.T., 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: UTS OPUS or Publisher's site
Verma, A., Hoppenrath, M., Dorantes-Aranda, J.J., Harwood, D.T. & Murray, S.A. 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: UTS OPUS or Publisher's site
Cryptic and pseudo-cryptic species are common amongst marine phytoplankton, and may cause misleading inferences of ecological and physiological data of plankton community studies. Deciphering the diversity and distribution of species of the benthic dinoflagellate Ostreopsis is one example, as there are many morphologically indistinct clades that differ greatly genetically and toxicologically from one another. In this study, a new species, Ostreopsis rhodesae from the southern Great Barrier Reef was described. While it initially appeared to be highly similar to several other Ostreopsis species, we found O. rhodesae can be distinguished based on the relative size of the second apical plate (2'), which is twice as long as the APC plate, and separates the third apical (3') from the third precingular (3'') plate. Phylogenetic trees based on the SSU, ITS/5.8S and D1-D2 and D8-D10 regions of the LSU rRNA were well supported, and showed a clear difference to other Ostreopsis clades. Compensatory base changes (CBCs) were identified in helices of the ITS2 between O. rhodesae and O. cf. ovata and O. cf. siamensis, which were also present in the same habitat. Fish gill cell lines were toxic to O. rhodesae, cell extracts but no palytoxin-like analogues were found in them. The findings highlight a case of pseudo-cryptic speciation, found in sympatry with closely related and morphologically similar species, but biologically and functionally distinct.
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
Farrell, H., Seebacher, F., O'Connor, W., Zammit, A., Harwood, D.T. & 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: UTS OPUS or 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, S.A., 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: UTS OPUS or Publisher's site
Kohli, G.S., John, U., Figueroa, R.I., Rhodes, L.L., Harwood, D.T., Groth, M., Bolch, C.J.S. & Murray, S.A. 2015, 'Polyketide synthesis genes associated with toxin production in two species of Gambierdiscus (Dinophyceae)', BMC GENOMICS, vol. 16.View/Download from: UTS OPUS or Publisher's site
Murray, S.A., Diwan, R., Orr, R.J.S., Kohli, G.S. & 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: UTS OPUS or Publisher's site
Murray, S.A., Kohli, G.S., Farrell, H., Spiers, Z.B., Place, A.R., Dorantes-Aranda, J.J. & 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: UTS OPUS or 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, R.W., Montresor, M., Murray, S., Brosnahan, M.L. & Anderson, D.M. 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: UTS OPUS or Publisher's site
John, U., Litaker, W., Montresor, M., Murray, S., Brosnahan, M.L. & Anderson, D.M. 2014, '(2302) Proposal to reject the name Gonyaulax catenella (Alexandrium catenella) (Dinophyceae)', TAXON, vol. 63, no. 4, pp. 932-933.
John, U., Litaker, W., Montresor, M., Murray, S.A., Brosnahan, M.L. & Anderson, D.M. 2014, 'Proposal to reject the name Gonyaulax catenella (Alexandrium catenella) (Dinophyceae)', Taxon, vol. 63, no. 4, pp. 932-933.View/Download from: UTS OPUS or Publisher's site
Keeling, P.J., Burki, F., Wilcox, H.M., Allam, B., Allen, E.E., Amaral-Zettler, L.A., Armbrust, V., Archibald, J.M., Bharti, A.K., Bell, C.J., Beszteri, B., Bidle, K.D., Cameron, C.T., Campbell, L., Caron, D.A., Cattolico, R.A., Collier, J.L., Coyne, K., Davy, S.K., Deschamps, P., Dyhrman, S., Edvardsen, B., Gates, R.D., Gobler, C.J., Greenwood, S.J., Guida, S.M., Jacobi, J.L., Jakobsen, K.S., James, E.R., Jenkins, B., John, U., Johnson, M.D., Juhl, A.R., Kamp, A., Katz, L.A., Kiene, R., Kudryavtsev, A., Leander, B.S., Lin, S., Lovejoy, C., Lynn, D., Marchetti, A., McManus, G., Nedelcu, A.M., Menden-Deuer, S., Miceli, C., Mock, T., Montresor, M., Moran, M.A., Murray, S.A., Nadathur, G., Nagai, S., Ngam, P.B., Palenik, B., Pawlowski, J., Petroni, G., Piganeau, G., Posewitz, M.C., Rengefors, K., Romano, G., Rumpho, M.E., Rynearson, T., Schilling, K.B., Schroeder, D.C., Simpson, A.G., Slamovits, C.H., Smith, D.R., Smith, J., Smith, S.R., Sosik, H.M., Stief, P., Theriot, E., Twary, S.N., Umale, P.E., Vaulot, D., Wawrik, B., Wheeler, G.L., Wilson, W.H., Xu, Y., Zingone, A. & Worden, A.Z. 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: UTS OPUS or Publisher's site
Kohli, G.S., Murray, S.A., Neilan, B.A., Rhodes, L., Harwood, T., Smith, K.F., Meyer, L., Capper, A., Brett, S. & Hallegraeff, G.M. 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: UTS OPUS or 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, G.S., Neilan, B.A., Brown, M.V., Hoppenrath, M. & Murray, S.A. 2014, 'Cob gene pyrosequencing enables characterisation of benthic dinoflagellate diversity and biogeography', Environmental Microbiology, vol. 16, no. 2, pp. 467-485.View/Download from: UTS OPUS or Publisher's site
Kohli, G.S., Papiol, G.G., Rhodes, L., Harwood, T., Selwood, A., Jerrett, A., Murray, S.A. & Neilan, B.A. 2014, 'A feeding study to probe the uptake of Maitotoxin by snapper (Pagrus auratus)', Harmful Algae, vol. 37, pp. 125-132.View/Download from: UTS OPUS or 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, S.A., Hoppenrath, M., Orr, R.J., 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: UTS OPUS or Publisher's site
Murray, S.A., 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: UTS OPUS or 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, S.A. & 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: UTS OPUS or 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, S.A., Alvin, A. & Neilan, B.A. 2014, 'Gene expression and molecular evolution of sxtA4 in a saxitoxin producing dinoflagellate Alexandrium catenella', TOXICON, vol. 92, pp. 102-112.View/Download from: UTS OPUS or Publisher's site
Hoppenrath, M., Chomerat, N., Horiguchi, T., Schweikert, M., Nagahama, Y. & Murray, S.A. 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: UTS OPUS or 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, R.J., Stuken, A., Murray, S.A. & Jakobsen, K.S. 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: UTS OPUS or 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, R.J., Stüken, A., Murray, S.A. & Jakobsen, K.S. 2013, 'Evolution and distribution of saxitoxin biosynthesis in dinoflagellates', Marine Drugs, vol. 11, no. 8, pp. 2814-2828.View/Download from: UTS OPUS or 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, S.A., 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: UTS OPUS or 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, S.A., 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: UTS OPUS or 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, S.A. 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: UTS OPUS or 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, E.J., Murray, S.A. & 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: UTS OPUS or 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, S.A., Sparmann, S.F. & Leander, B.S. 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: UTS OPUS or 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, S.A., Garby, T., Hoppenrath, M. & Neilan, B.A. 2012, 'Genetic diversity, morphological uniformity and polyketide production in dinoflagellates (Amphidinium, Dinoflagellata)', Plos One, vol. 7, no. 6, pp. e38253-0.View/Download from: UTS OPUS or 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, S.A., Patterson, D.J. & Thessen, A.E. 2012, 'Transcriptomics and microbial eukaryote diversity: a way forward', Trends in Ecology & Evolution, vol. 27, no. 12, pp. 651-652.View/Download from: UTS OPUS or 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, S.A., Wiese, M., Neilan, B.A., Orr, R.J., 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: UTS OPUS or 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, R.J., Murray, S.A., Stuken, A., Rhodes, L. & Jakobsen, K.S. 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: UTS OPUS or 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, A.E., Patterson, D.J. & Murray, S.A. 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: UTS OPUS or Publisher's site
Murray, S.A., Mihali, T.K. & Neilan, B.A. 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: UTS OPUS or 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, S.A., Wiese, M., Stuken, A., Brett, S., Kellmann, R., Hallegraeff, G. & Neilan, B.A. 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: UTS OPUS or 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, S.A., 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: UTS OPUS or 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, R.J., Kellmann, R., Murray, S.A., Neilan, B.A. & Jakobsen, K.S. 2011, 'Discovery of nuclear-encoded genes for the neurotoxin saxitoxin in dinoflagellates', Plos One, vol. 6, no. 5, pp. e20096-0.View/Download from: UTS OPUS or 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, S.A., 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: UTS OPUS or 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, J.A., Chau, R., Kohli, G.S., Murray, S.A. & Neilan, B.A. 2010, 'Biosynthesis of toxic naturally-occurring seafood contaminants', Toxicon, vol. 56, no. 2, pp. 244-258.View/Download from: UTS OPUS or 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, S.A., Ip, C.L., 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: UTS OPUS or 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, S.A., O'Connor, W.A., Alvin, A., Mihali, T.K., Kalaitzis, J. & Neilan, B.A. 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: UTS OPUS or 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, S.A. & Else, P.L. 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: UTS OPUS or 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.
Gilbert, P.M., Azanza, R., Burford, M.A., Furuya, K., Abal, E., Al-Azri, A., Al-Yamani, F., Andersen, P., Anderson, D.M., Beardall, J., Berg, G.M., Brand, L., Bronk, D., Brookes, J., Burkholder, J.M., Cembella, A., Cochlan, W.P., Collier, J.L., Collos, Y., Diaz, R., Doblin, M.A., Drennen, T., Dyhrman, S., Fukuyo, Y., Furnas, M., Galloway, J., Graneli, E., Ha, D., Hallegraeff, G.M., Harrison, J., Harrison, P., Heil, C.A., Heimann, K., Howarth, R., Jauzein, M., Kana, A.A., Kana, T.M., Kim, H., Kudela, R., Legrand, C., Mallin, M., Mulholland, M., Murray, S.A., O'Neil, J., Pitcher, G., Qi, Y., Rabalais, N., Raine, R., Seitzinger, S., Salomon, P.S., Solomon, C., Stoecker, D.K., 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: UTS OPUS or 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.
Schwartz, T.S., Murray, S.A. & 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: UTS OPUS or 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.
Murray, S.A., 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, S.A., Nagahama, Y. & Fukuyo, Y. 2007, 'Phylogenetic study of benthic, spine-bearing prorocentroids, including Prorocentrum fukuyoi sp. nov.', Phycological Research, vol. 55, pp. 91-102.
Murray, S.A., Hoppenrath, M., Larsen, J. & Patterson, D.J. 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, S.A., Hoppenrath, M., Preisfeld, A., Larsen, J., Yoshimatsu, S., Toriumi, S. & Patterson, D.J. 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, S.A., Jorgensen, M.F., Ho, S.Y., Patterson, D.J. & Jermiin, L.S. 2005, 'Improving the analysis of dinoflagellate phylogeny based on rDNA', Protist, vol. 156, pp. 269-286.View/Download from: Publisher's site
Jorgensen, M.F., 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, M.F., Murray, S.A. & 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, M.F., Murray, S.A. & 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, C.J. & Murray, S.A. 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, S.A. & Patterson, D.J. 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, S.A., Jorgensen, M.F., 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, S.A., Korte, B. & Dey, C.J. 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, W.J., Murray, S.A., Simp, A.G. & Patterson, D.J. 2002, 'Flagellates from stromatolites and surrounding sediments in Shark Bay, Western Australia', Acta Protozoologica, vol. 41, pp. 91-144.
Murray, S.A. & Patterson, D.J. 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, S.A. & 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).
Ajani, P.A., Hallegraeff, G.M., Allen, D., Coughlan, A., Richardson, A.J., Armand, L.K., Ingleton, T. & Murray, S.A. 2016, 'Establishing baselines: a review of eighty years of phytoplankton diversity and biomass in southeastern Australia' in Hughes, R.N., Hughes, D.J., Smith, I.P. & Dale, A.C. (eds), Oceanography and Marine Biology An Annual Review, CRC Press, USA, pp. 387-412.View/Download from: UTS OPUS or 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...
Kohli, G.S., Farrell, H. & Murray, S.A. 2015, 'Gambierdiscus, the cause of ciguatera fish poisoning: a review of progress in ecology and toxicology' in Luis Botana, N.a.t.a.l.i.a...V.i.l.a.r.i.n.o. (ed), Climate change and marine and freshwater toxins, Walter de Gruyter, Germany, pp. 273-312.
Murray, S.A., Uwe, J. & Kremp, A. 2015, 'Alexandrium spp.: genetic and ecological factors influencing saxitoxin production and proliferation' in Botana, L.M., Louzao, M.C. & Vilarino, N. (eds), Climate Change and Marine and Freshwater Toxins, Walter de Gruyter, Germany, pp. 125-154.View/Download from: UTS OPUS
Neilan, B.A., Murray, S.A. & Chen, M. 2010, 'Genomic contributions to understanding the evolution of red algal plastids and pigment biosynthesis' in Seckbach, J. & Chapman, D.J. (eds), Red algae in the genomic age, Springer, Netherlands, pp. 261-273.View/Download from: UTS OPUS
Murray, S.A. 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.
Ajani, P.A., Hallegraeff, G.M., Allen, D., Coughlan, A., Richardson, A.J., Armand, L., Ingleton, I. & Murray, S.A. 2017, 'Establishing baselines: eighty years of phytoplankton diversity and biomass in south-eastern Australia (Oral Presentation). ALSO Aquatic Science Meeting 2017, Hawaii'.
Kim, J.H., Wang, P., Park, B.S., Kim, J., Patidar, S.K., Ajani, P.A., Murray, S.A., Lim, H.C., Lim, P.T. & 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, J.H., Wang, P., Park, B.S., Paditar, K.S., Ajani, P.A., Murray, S.A., Lim, H.C. & Lim, P.T. 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, S.A., 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.View/Download from: UTS OPUS
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.View/Download from: UTS OPUS
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.View/Download from: UTS OPUS
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, S.A., Wiese, M., Stuken, A., Kellmann, R., Brett, S., Hallegraef, G.M. & Neilan, B.A. 2011, 'Quantitative assessment of coastal harmful algal blooms based on the saxitoxin biosynthesis gene, sxtA', Gordon Conference on Phycotoxins and Mycotoxins, Boston, United States.
Murray, S.A., Kohli, G.S., Harwood, D.T., 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.
Davies, C.H., 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, S.C., Lønborg, C., McLaughlin, J., McEnnulty, F., McKinnon, A.D., Miller, M., Murray, S., Nayar, S., Patten, R., Pausina, S.A., Pritchard, T., Proctor, R., Purcell-Meyerink, D., Raes, E., Rissik, D., Ruszczyk, J., Slotwinski, A., Swadling, K.M., Tattersall, K., Thompson, P., Thomson, P., Tonks, M., Trull, T.W., Uribe-Palomino, J., Waite, A.M., Yauwenas, R., Zammit, A. & Richardson, A.J. 2017, 'Corrigendum: A database of marine phytoplankton abundance, biomass and species composition in Australian waters.', Nature Publishing Group, pp. 1-1.View/Download from: Publisher's site
The authors regret that Sarah A. Pausina was omitted in error from the author list of the original
version of this Data Descriptor. This omission has now been corrected in the HTML and PDF versions
of this Data Descriptor, as well as the accompanying Corrigendum
- Diagnostic Technology
- NSW Food Authority
- Sydney Fish Market
- NSW Department of Primary Industries (Fisheries)
- The Yield Pty Ltd
- Warringah Council
- Hornsby Council
- University of Tasmania
- Cawthron Institute (New Zealand)
- Senckenberg Institute (Germany)
- Alfred Wegener Institute for Polar and Marine Research (Germany)