ORCID Profile
0000-0001-7096-1307
Current Organisation
University of Technology Sydney
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Phycology (incl. Marine Grasses) | Microbiology | Molecular Evolution | Genetics | Plant Biology | Biological Oceanography | Gene Expression (incl. Microarray and other genome-wide approaches) | Microbial Ecology | Phycology | Fisheries Sciences | Marine and Estuarine Ecology (incl. Marine Ichthyology) | Other Chemical Sciences | Phylogeny and Comparative Analysis | Ecological Impacts of Climate Change | Gene Expression | Environmental Chemistry (incl. Atmospheric Chemistry) | Microbial Genetics | Diagnostic Applications | Molecular Evolution | Aquaculture | Environmental Monitoring | Environmental Marine Biotechnology |
ANZSRC Socio-Economic Objective (SEO)
Control of Animal Pests, Diseases and Exotic Species in Coastal and Estuarine Environments | Aquaculture Oysters | Ecosystem Assessment and Management of Coastal and Estuarine Environments | Coastal and Estuarine Flora, Fauna and Biodiversity | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Aquaculture | Marine Flora, Fauna and Biodiversity | Coastal and Marine Management Policy | Wild Caught Fin Fish (excl. Tuna) | Climate Change Models | Land and water management | Control of Plant Pests, Diseases and Exotic Species in Coastal and Estuarine Environments | Control of pests and exotic species | Fisheries - Wild Caught not elsewhere classified | Water services and utilities | Diagnostics | Ecosystem Assessment and Management of Marine Environments | Coastal and Estuarine Water Management
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Publications
Cob gene pyrosequencing enables characterization of benthic dinoflagellate diversity and biogeography
Publisher: Wiley
Date: 21-10-2014
Abstract: Dinoflagellates in marine benthic habitats living epiphytically on macroalgae are an important but highly understudied group of protists. Many produce toxins that can have severe economic impacts on marine-based economies, and improved monitoring tools are required to enhance the management of toxin-related hazards. We analysed the distribution and ersity of epibenthic dinoflagellates inhabiting eight sites in Cocos (Keeling) Islands, Papua New Guinea, and Broome and Exmouth, Western Australia. We used pyrosequencing approaches based on two DNA barcoding marker genes - 18S ribosomal RNA (rRNA) and mitochondrial cytochrome b (cob) - and compared these to an approach based on clone libraries (197 sequences) using the cob gene. Dinoflagellate sequences accounted for 133 [64 unique operational taxonomic units (OTU)] out of 10 529 18S rRNA gene sequences obtained from all s les. However, using the dinoflagellate specific assay targeting the cob gene marker, we obtained 9748 (1217 unique OTU) dinoflagellate sequences from the same environmental s les, providing the largest, to date, set of dinoflagellate cob gene sequences and reliable estimates of total dinoflagellate richness within the s les and biogeographic comparisons between s les. This study also reports the presence of potentially toxic species of the genera Gambierdiscus, Ostreopsis, Coolia, Prorocentrum and Amphidinium from the above-mentioned geographical regions.
Harmful Algae Introductions: Vectors of Transfer, Mitigation, and Management
Publisher: Wiley
Date: 06-2018
Molecular phylogeny, morphology and toxigenicity of Ostreopsis cf. siamensis (Dinophyceae) from temperate South-east Australia
Publisher: Wiley
Date: 25-05-2016
DOI: 10.1111/PRE.12128
The Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP): Illuminating the Functional Diversity of Eukaryotic Life in the Oceans through Transcriptome Sequencing
Publisher: Public Library of Science (PLoS)
Date: 24-06-2014
Assessment of the metabarcoding approach for community analysis of benthic-epiphytic dinoflagellates using mock communities
Publisher: Informa UK Limited
Date: 15-03-2017
Accumulation and depuration of paralytic shellfish toxins by Australian abalone Haliotis rubra : Conclusive association with Gymnodinium catenatum dinoflagellate blooms
Publisher: Elsevier BV
Date: 03-2017
A Comparative Analysis of Methods (LC-MS/MS, LC-MS and Rapid Test Kits) for the Determination of Diarrhetic Shellfish Toxins in Oysters, Mussels and Pipis
Publisher: MDPI AG
Date: 20-01-1970
Abstract: Rapid methods for the detection of biotoxins in shellfish can assist the seafood industry and safeguard public health. Diarrhetic Shellfish Toxins (DSTs) are produced by species of the dinoflagellate genus Dinophysis, yet the comparative efficacy of their detection methods has not been systematically determined. Here, we examined DSTs in spiked and naturally contaminated shellfish–Sydney Rock Oysters (Saccostrea glomerata), Pacific Oysters (Magallana gigas/Crassostrea gigas), Blue Mussels (Mytilus galloprovincialis) and Pipis (Plebidonax deltoides/Donax deltoides), using LC-MS/MS and LC-MS in 4 laboratories, and 5 rapid test kits (quantitative Enzyme-Linked Immunosorbent Assay (ELISA) and Protein Phosphatase Inhibition Assay (PP2A), and qualitative Lateral Flow Assay (LFA)). We found all toxins in all species could be recovered by all laboratories using LC-MS/MS (Liquid Chromatography—tandem Mass Spectrometry) and LC-MS (Liquid Chromatography—Mass Spectrometry) however, DST recovery at low and mid-level concentrations ( .1 mg/kg) was variable (0–150%), while recovery at high-level concentrations ( .86 mg/kg) was higher (60–262%). While no clear differences were observed between shellfish, all kits delivered an unacceptably high level (25–100%) of falsely compliant results for spiked s les. The LFA and the PP2A kits performed satisfactorily for naturally contaminated pipis (0%, 5% falsely compliant, respectively). There were correlations between spiked DSTs and quantitative methods was highest for LC-MS (r2 = 0.86) and the PP2A kit (r2 = 0.72). Overall, our results do not support the use of any DST rapid test kit as a stand-alone quality assurance measure at this time.
A deep dive into the ecology of Gamay (Botany Bay, Australia): Current knowledge and future priorities for this highly modified coastal waterway
Publisher: CSIRO Publishing
Date: 19-07-2023
DOI: 10.1071/MF22268
Abstract: Context Gamay is a coastal waterway of immense social, cultural and ecological value. Since European settlement, it has become a hub for industrialisation and human modification. There is growing desire for ecosystem-level management of urban waterways, but such efforts are often challenged by a lack of integrated knowledge. Aim and methods We systematically reviewed published literature and traditional ecological knowledge (TEK), and consulted scientists to produce a review of Gamay that synthesises published knowledge of Gamay’s aquatic ecosystem to identify knowledge gaps and future research opportunities. Key results We found 577 published resources on Gamay, of which over 70% focused on ecology. Intertidal rocky shores were the most studied habitat, focusing on invertebrate communities. Few studies considered multiple habitats or taxa. Studies investigating cumulative human impacts, long-term trends and habitat connectivity are lacking, and the broader ecological role of artificial substrate as habitat in Gamay is poorly understood. TEK of Gamay remains a significant knowledge gap. Habitat restoration has shown promising results and could provide opportunities to improve affected habitats in the future. Conclusion and implications This review highlights the extensive amount of knowledge that exists for Gamay, but also identifies key gaps that need to be filled for effective management.
Surface and flagella morphology of the motile form of Chromera velia revealed by field-emission scanning electron microscopy
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.PROTIS.2010.02.003
Abstract: Chromera velia(Chromerida Alveolata) is an autotrophic protist isolated from stony corals.Ch. veliapossesses a chloroplast thought to be most closely related to the apicoplasts of non-photosynthetic apicomplexa. Phylogenetic analyses placeCh. veliaas 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 ofCh. velia. In overall morphology the biflagellatedCh. veliacells resemble the colpodellidColpodella edax, but with some notable differences. The ventral side of the flagellatedCh. veliacell 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 forCh. veliaallowed us to emend its diagnosis.
High Specificity of a Quantitative PCR Assay Targeting a Saxitoxin Gene for Monitoring Toxic Algae Associated with Paralytic Shellfish Toxins in the Yellow Sea
Publisher: American Society for Microbiology
Date: 15-10-2015
DOI: 10.1128/AEM.00417-15
Abstract: The identification of core genes involved in the biosynthesis of saxitoxin (STX) offers a great opportunity to detect toxic algae associated with paralytic shellfish toxins (PST). In the Yellow Sea (YS) in China, both toxic and nontoxic Alexandrium species are present, which makes it a difficult issue to specifically monitor PST-producing toxic algae. In this study, a quantitative PCR (qPCR) assay targeting sxtA4 , a domain in the sxt gene cluster that encodes a unique enzyme involved in STX biosynthesis, was applied to analyze s les collected from the YS in spring of 2012. The abundance of two toxic species within the Alexandrium tamarense species complex, i.e., A. fundyense and A. pacificum , was also determined with TaqMan-based qPCR assays, and PSTs in net-concentrated phytoplankton s les were analyzed with high-performance liquid chromatography coupled with a fluorescence detector. It was found that the distribution of the sxtA4 gene in the YS was consistent with the toxic algae and PSTs, and the quantitation results of sxtA4 correlated well with the abundance of the two toxic species ( r = 0.857). These results suggested that the two toxic species were major PST producers during the s ling season and that sxtA -based qPCR is a promising method to detect toxic algae associated with PSTs in the YS. The correlation between PST levels and sxtA -based qPCR results, however, was less significant ( r = 0.552), implying that sxtA -based qPCR is not accurate enough to reflect the toxicity of PST-producing toxic algae. The combination of an sxtA -based qPCR assay and chemical means might be a promising method for monitoring toxic algal blooms.
Morphological and molecular phylogenetic identification and record verification of Gambierdiscus excentricus (Dinophyceae) from Madeira Island (NE Atlantic Ocean)
Publisher: Springer Science and Business Media LLC
Date: 14-08-2019
Qualitative and quantitative assessment of the presence of ciguatoxin, P-CTX-1B, in Spanish Mackerel (Scomberomorus commerson) from waters in New South Wales (Australia).
Publisher: Elsevier BV
Date: 2017
Marine Toxins from Harmful Algae and Seafood Safety
Publisher: MDPI
Date: 05-01-2023
Establishing baselines: a review of eighty years of phytoplankton diversity and biomass in southeastern Australia
Publisher: CRC Press
Date: 06-12-2016
Dinoflagellate Biology: Using Molecular Approaches to Unlock Their Ecology and Evolution
Publisher: MDPI
Date: 06-01-2023
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
Publisher: Wiley
Date: 09-2004
Marine benthic dinoflagellates - unveiling their worldwide biodiversity
Publisher: Informa UK Limited
Date: 2014
DOI: 10.2216/5401BR01
Polyketide synthesis genes associated with toxin production in two species of Gambierdiscus (Dinophyceae)
Publisher: Springer Science and Business Media LLC
Date: 28-05-2015
Formal revision of the alexandrium tamarense species complex (dinophyceae) taxonomy: The introduction of five species with emphasis on molecular-based (rDNA) classification
Publisher: Elsevier BV
Date: 12-2014
Evaluation of sxtA and rDNA qPCR assays through monitoring of an inshore bloom of Alexandrium catenella Group 1.
Publisher: Springer Science and Business Media LLC
Date: 10-10-2019
DOI: 10.1038/S41598-019-51074-3
Abstract: Alexandrium catenella (formerly A. tamarense Group 1, or A. fundyense ) is the leading cause of Paralytic Shellfish Poisoning in North and South America, Europe, Africa, Australia and Asia. The quantification of A.catenella via sxtA , a gene involved in Paralytic Shellfish Toxin synthesis, may be a promising approach, but has not been evaluated in situ on blooms of A. catenella , in which cell abundances may vary from not detectable to in the order of 10 6 cells L −1 . In this study, we compared sxtA assay performance to a qPCR assay targeted to a species-specific region of ribosomal DNA (rDNA) and an established fluorescent in situ hybridization (FISH) microscopy method. Passing-Bablok regression analyses revealed the sxtA assay to overestimate abundances when cell equivalents A. catenella DNA were analysed, but otherwise was closer to microscopy estimates than the rDNA assay, which overestimated abundance across the full range of concentrations analysed, indicative of a copy number difference between the bloom population and a culture used for assay calibration a priori . In contrast, the sxtA assay performed more consistently, indicating less copy number variation. The sxtA assay was generally reliable, fast and effective in quantifying A. catenella and was predictive of PST contamination of shellfish.
Comparative performance of four immunological test kits for the detection of Paralytic Shellfish Toxins in Tasmanian shellfish
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.TOXICON.2016.11.262
Abstract: 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 s les 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 s les undergoing testing using the more expensive and time consuming LC-FLD method will result in significant savings in analytical costs.
A fish kill associated with a bloom of Amphidinium carterae in a coastal lagoon in Sydney, Australia.
Publisher: Elsevier BV
Date: 11-2015
Trial by phylogenetics - Evaluating the Multi-Species Coalescent for phylogenetic inference on taxa with high levels of paralogy (Gonyaulacales, Dinophyceae)
Publisher: Cold Spring Harbor Laboratory
Date: 27-06-2019
DOI: 10.1101/683383
Abstract: From publicly available next-gen sequencing datasets of non-model organisms, such as marine protists, arise opportunities to explore their evolutionary relationships. In this study we explored the effects that dataset and model selection have on the phylogenetic inference of the Gonyaulacales, single celled marine algae of the phylum Dinoflagellata with genomes that show extensive paralogy. We developed a method for identifying and extracting single copy genes from RNA-seq libraries and compared phylogenies inferred from these single copy genes with those inferred from commonly used genetic markers and phylogenetic methods. Comparison of two datasets and three different phylogenetic models showed that exclusive use of ribosomal DNA sequences, maximum likelihood and gene concatenation showed very different results to that obtained with the multi-species coalescent. The multi-species coalescent has recently been recognized as being robust to the inclusion of paralogs, including hidden paralogs present in single copy gene sets (pseudoorthologs). Comparisons of model fit strongly favored the multi-species coalescent for these data, over a concatenated alignment (single tree) model. Our findings suggest that the multi-species coalescent (inferred either via Maximum Likelihood or Bayesian Inference) should be considered for future phylogenetic studies of organisms where accurate selection of orthologs is difficult.
Abiotic and biotic factors controlling sexual reproduction in populations of Pseudo-nitzschia pungens (Bacillariophyceae).
Publisher: Elsevier BV
Date: 03-2023
Cabra matta, gen. nov., sp. nov., a new benthic, heterotrophic dinoflagellate
Publisher: Informa UK Limited
Date: 05-2004
A database of marine phytoplankton abundance, biomass and species composition in Australian waters
Publisher: Springer Science and Business Media LLC
Date: 25-06-2017
Abstract: There have been many in idual 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 ( 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.
Phylogenetics, Molecular Biology and Ecological Impacts of a Group of Highly Unusual Protists
Publisher: Springer Netherlands
Date: 2007
Gambierdiscus, the cause of ciguatera fish poisoning: an increased human health threat influenced by climate change
Publisher: De Gruyter
Date: 16-12-2021
Discovery of Nuclear-Encoded Genes for the Neurotoxin Saxitoxin in Dinoflagellates
Publisher: Public Library of Science (PLoS)
Date: 18-05-2011
Alexandrium spp.: Genetic and ecological factors influencing saxitoxin production and proliferation
Publisher: De Gruyter
Date: 16-12-2021
Morphology and molecular phylogeny of the benthic dinoflagellates (Dinophyceae, Peridiniales) Amphidiniopsis crumena n. sp. and Amphidiniopsis nileribanjensis n. sp.
Publisher: Elsevier BV
Date: 02-2023
Differential accumulation of paralytic shellfish toxins from Alexandrium minutum in the pearl oyster, Pinctada imbricata
Publisher: Elsevier BV
Date: 09-2009
DOI: 10.1016/J.TOXICON.2009.04.005
Abstract: 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 minutum. When fed with A. minutum at concentrations between 100 and 1300 cells ml(-1), the maximum clearance by P. imbricata was shown to occur at a density of 300 cells ml(-1). When fed twice daily at this rate for up 12 days, P. imbricata accumulated analogues of gonyautoxins (GTXs): GTXs 1,4 and 2,3. The levels of GTXs in the viscera increased progressively on days 4, 8 and 12 to peak at 17.9+/-4.47 microg STX-equivalent 100 g(-1) biomass. Following 12 days of depuration, in the absence of A. minutum, GTX levels fell by approximately 65% to 6.0+/-2.20 microg STX-equivalent 100 g(-1) biomass. No GTX was found in the oysters at the start of the trial or in untreated controls. The accumulation of GTX was found to be tissue specific. No GTX was detected in the muscle tissue of P. imbricata during the feeding trial.
A new species of Gambierdiscus (Dinophyceae) from the south-west Pacific: Gambierdiscus honu sp. nov.
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.HAL.2017.04.010
Abstract: Two isolates of a new tropical, epiphytic dinoflagellate species, Gambierdiscus honu sp. nov., were obtained from macroalgae s led 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 in idual 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.
Extraordinary Conservation, Gene Loss, and Positive Selection in the Evolution of an Ancient Neurotoxin
Publisher: Oxford University Press (OUP)
Date: 13-11-2010
Abstract: 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 one genomic locus, sxt. Insights into evolutionary-ecological processes have been found through the study of such secondary metabolites because they consist of a measurable phenotype with clear ecological consequences, synthesized by known genes in a small number of species. However, the processes involved in and timing of the ergence of prokaryotic secondary metabolites have been difficult to determine due to their antiquity and the possible frequency of horizontal gene transfer and homologous recombination. Through analyses of gene synteny, phylogenies of in idual genes, and analyses of recombination and selection, we identified the evolutionary processes of this cluster in five species of cyanobacteria. Here, we provide evidence that the sxt cluster appears to have been largely vertically inherited and was therefore likely present early in the ergence of the Nostocales, at least 2,100 Ma, the earliest reliably dated appearance of a secondary metabolite. The sxt cluster has been extraordinarily conserved through stabilizing selection. Genes have been lost and rearranged, have undergone intra- and interspecific recombination, and have been subject to duplication followed by positive selection along the duplicated lineage, with likely consequences for the toxin analogues produced. Several hypotheses exist as to the ecophysiological role of saxitoxin: as a method of chemical defense, cellular nitrogen storage, DNA metabolism, or chemical signaling. The antiquity of this gene cluster indicates that potassium channels, not sodium channels, may have been the original targets of this compound. The extraordinary conservation of the machinery for saxitoxin synthesis, under radically changing environmental conditions, shows that it has continued to play an important adaptive role in some cyanobacteria.
First Detection of Paralytic Shellfish Toxins from Alexandrium pacificum above the Regulatory Limit in Blue Mussels (Mytilus galloprovincialis) in New South Wales, Australia.
Publisher: MDPI AG
Date: 16-06-2020
DOI: 10.3390/MICROORGANISMS8060905
Abstract: In 2016, 2017 and 2018, elevated levels of the species Alexandrium pacificum were detected within a blue mussel (Mytilus galloprovincialis) aquaculture area at Twofold Bay on the south coast of New South Wales, Australia. In 2016, the bloom persisted for at least eight weeks and maximum cell concentrations of 89,000 cells L−1 of A. pacificum were reported. The identity of A. pacificum was confirmed using molecular genetic tools (qPCR and licon sequencing) and complemented by light and scanning electron microscopy of cultured strains. Maximum reported concentrations of paralytic shellfish toxins (PSTs) in mussel tissue was 7.2 mg/kg PST STX equivalent. Elevated cell concentrations of A. pacificum were reported along the adjacent coastal shelf areas, and positive PST results were reported from nearby oyster producing estuaries during 2016. This is the first record of PSTs above the regulatory limit (0.8 mg/kg) in commercial aquaculture in New South Wales since the establishment of routine biotoxin monitoring in 2005. The intensity and duration of the 2016 A. pacificum bloom were unusual given the relatively low abundances of A. pacificum in estuarine and coastal waters of the region found in the prior 10 years.
Erratum: Amphidinium revisited. I. Redefinition of Amphidinium (Dinophyceae) based on cladistic and molecular phylogenetic analyses (Journal of Phycology 40 (351-365))
Publisher: Wiley
Date: 12-2004
A new diatom species P. hallegraeffii sp. nov. belonging to the toxic genus Pseudo-nitzschia (Bacillariophyceae) from the East Australian Current
Publisher: Public Library of Science (PLoS)
Date: 12-04-2018
Corrigendum: A database of marine phytoplankton abundance, biomass and species composition in Australian waters.
Publisher: Springer Science and Business Media LLC
Date: 11-04-2017
Abstract: Scientific Data 3:160043 doi:10.1038/sdata.2016.43 (2016) Published 21 Jun 2016 Updated 11 April 2017 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.
Developing model systems for dinoflagellates in the post‐genomic era
Publisher: Wiley
Date: 09-2023
DOI: 10.1111/JPY.13386
sxtA -Based Quantitative Molecular Assay To Identify Saxitoxin-Producing Harmful Algal Blooms in Marine Waters
Publisher: American Society for Microbiology
Date: 10-2011
DOI: 10.1128/AEM.05308-11
Abstract: 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 chemical ecology of harmful algal blooms in situ . We present a novel method for detecting and quantifying the potential for STX production in marine environmental s les. Our assay detects a domain of the gene sxtA that encodes a unique enzyme putatively involved in the sxt pathway in marine dinoflagellates, sxtA4 . A product of the correct size was recovered from nine strains of four species of STX-producing Alexandrium and Gymnodinium catenatum and was not detected in the non-STX-producing Alexandrium species, other dinoflagellate cultures, or an environmental s le that did not contain known STX-producing species. However, sxtA4 was also detected in the non-STX-producing strain of Alexandrium tamarense , Tasmanian ribotype. We investigated the copy number of sxtA4 in three strains of Alexandrium catenella and found it to be relatively constant among strains. Using our novel method, we detected and quantified sxtA4 in three environmental blooms of Alexandrium catenella that led to STX uptake in oysters. We conclude that this method shows promise as an accurate, fast, and cost-effective means of quantifying the potential for STX production in marine s les and will be useful for biological oceanographic research and harmful algal bloom monitoring.
Species boundaries in the toxic dinoflagellate Prorocentrum lima (Dinophyceae, Prorocentrales), based on morphological and phylogenetic characters
Publisher: Wiley
Date: 02-2011
DOI: 10.1111/J.1529-8817.2010.00939.X
Abstract: 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 valve shape, valve size, valve ornamentation, number and shape of valve pores, number and shape of marginal pores, and periflagellar platelets were observed using LM and SEM, and two molecular genetic regions were sequenced. We identified stable morphological characters that were consistent among wild specimens and all cultures, which were valve shape, valve ornamentation, and number and arrangement of periflagellar platelets. All cultures of P. lima identified by these characters formed a monophyletic group in phylogenetic analyses based on the two genes, which, however, included the species Prorocentrum arenarium. P. arenarium was determined to be within the range of morphological variation of P. lima, and therefore we synonymize the two taxa. Within this monophyletic group, P. lima was ided into several subclades in the all phylogenetic analyses. There were no morphological characters specifically related to any one subclade. The subclades appeared to correlate broadly to s le collection regions, suggesting that geographically separated populations may have become genetically distinct within this epi-benthic species. We have emended species boundaries in P. lima.
Amphidinium revisited. I. Redefinition of Amphidinium (Dinophyceae) based on cladistic and molecular phylogenetic analyses
Publisher: Wiley
Date: 12-03-2004
Transcriptomic investigation into polyketide toxin synthesis in Ostreopsis (Dinophyceae) species
Publisher: Wiley
Date: 30-08-2019
Abstract: In marine ecosystems, dinoflagellates can become highly abundant and even dominant at times, despite their comparatively slow growth. Their ecological success may be related to their production of complex toxic polyketide compounds. Ostreopsis species produce potent palytoxin-like compounds (PLTX), which are associated with human skin and eye irritations, and illnesses through the consumption of contaminated seafood. To investigate the genetic basis of PLTX-like compounds, we sequenced and annotated transcriptomes from two PLTX-producing Ostreopsis species O. cf. ovata, O. cf. siamensis, one non-PLTX producing species, O. rhodesae and compared them to a close phylogenetic relative and non-PLTX producer, Coolia malayensis. We found no clear differences in the presence or ersity of ketosynthase and ketoreductase transcripts between PLTX producing and non-producing Ostreopsis and Coolia species, as both groups contained >90 and > 10 phylogenetically erse ketosynthase and ketoreductase transcripts, respectively. We report for the first-time type I single-, multi-domain polyketide synthases (PKSs) and hybrid non-ribosomal peptide synthase/PKS transcripts from all species. The long multi-modular PKSs were insufficient by themselves to synthesize the large complex polyether backbone of PLTX-like compounds. This implies that numerous PKS domains, including both single and multi-, work together on the biosynthesis of PLTX-like and other related polyketide compounds.
Bysmatrum teres sp. nov., a new sand-dwelling dinoflagellate from north-western Australia
Publisher: Informa UK Limited
Date: 23-02-2006
DOI: 10.2216/05-05.1
Characterisation of Two Toxic Gambierdiscus spp. (Gonyaulacales, Dinophyceae) from the Great Barrier Reef (Australia): G. lewisii sp. nov. and G. holmesii sp. nov.
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.PROTIS.2019.125699
Abstract: Ciguatera fish poisoning (CFP) is a human illness caused via consumption of seafood contaminated with neurotoxins produced by some species from the epiphytic dinoflagellate genus Gambierdiscus. In this study, we describe two new species of Gambierdiscus isolated from Heron Island in the Southern Great Barrier Reef, Queensland, Australia. These new species were analysed using light microscopy, scanning electron microscopy, and phylogenetic analyses of nuclear encoded ribosomal ITS, SSU as well as D1-D3 and D8-D10 of the LSU gene regions. Gambierdiscus lewisii sp. nov. (Po, 3', 0a, 7″, 6c,? s, 5‴, 0p, 2'‴) is distinguished by its strong reticulate-foveate ornamentation and is genetically distinct from its sister species, G. pacificus. Gambierdiscus holmesii sp. nov. (Po, 3', 0a, 7″, 6c, 6s?, 5‴, 0p, 2'‴) is morphologically distinct from the genetically similar species G. silvae because of a strongly ventrally displaced apical pore complex and a characteristic fold at the anterior edge of the sulcus. Both G. lewisii and G. holmesii produce putative Maitotoxin-(44-Methylgambierone) and compounds which show ciguatoxin and maitotoxin-like activities. Identification of two new Gambierdiscus species will enable us to more accurately assess the risk of CFP in Australia and internationally.
Gene duplication, loss and selection in the evolution of saxitoxin biosynthesis in alveolates
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.YMPEV.2015.06.017
Abstract: A group of marine dinoflagellates (Alveolata, Eukaryota), consisting of ∼10 species of the genus Alexandrium, Gymnodinium catenatum and Pyrodinium bahamense, produce the toxin saxitoxin and its analogues (STX), which can accumulate in shellfish, leading to ecosystem and human health impacts. The genes, sxt, putatively involved in STX biosynthesis, have recently been identified, however, the evolution of these genes within dinoflagellates is not clear. There are two reasons for this: uncertainty over the phylogeny of dinoflagellates and that the sxt genes of many species of Alexandrium and other dinoflagellate genera are not known. Here, we determined the phylogeny of STX-producing and other dinoflagellates based on a concatenated eight-gene alignment. We determined the presence, ersity and phylogeny of sxtA, domains A1 and A4 and sxtG in 52 strains of Alexandrium, and a further 43 species of dinoflagellates and thirteen other alveolates. We confirmed the presence and high sequence conservation of sxtA, domain A4, in 40 strains (35 Alexandrium, 1 Pyrodinium, 4 Gymnodinium) of 8 species of STX-producing dinoflagellates, and absence from non-producing species. We found three paralogs of sxtA, domain A1, and a widespread distribution of sxtA1 in non-STX producing dinoflagellates, indicating duplication events in the evolution of this gene. One paralog, clade 2, of sxtA1 may be particularly related to STX biosynthesis. Similarly, sxtG appears to be generally restricted to STX-producing species, while three amidinotransferase gene paralogs were found in dinoflagellates. We investigated the role of positive ( ersifying) selection following duplication in sxtA1 and sxtG, and found negative selection in clades of sxtG and sxtA1, clade 2, suggesting they were functionally constrained. Significant episodic ersifying selection was found in some strains in clade 3 of sxtA1, a clade that may not be involved in STX biosynthesis, indicating pressure for ersification of function.
Molecular phylogenetics and morphology of Gambierdiscus yasumotoi from tropical eastern Australia
Publisher: Elsevier BV
Date: 10-2014
Unravelling the functional genetics of dinoflagellates: a review of approaches and opportunities
Publisher: Schweizerbart
Date: 04-2016
Molecular Detection Of The Sxta Gene From Saxitoxin-Producing Alexandrium Minutum In Commercial Oyster
Publisher: National Shellfisheries Association
Date: 04-2016
DOI: 10.2983/035.035.0118
Amphidiniopsis korewalensis sp. nov., a new heterotrophic benthic dinoflagellate
Publisher: Informa UK Limited
Date: 07-2002
Establishing baselines: Eighty years of phytoplankton diversity and biomass in south-eastern Australia
Publisher: CRC Press
Date: 25-11-2016
Time series of harmful algal blooms in New South Wales
Publisher: Australian Ocean Data Network
Date: 2020
Molecular and phylogenetic characterization of Ostreopsis (Dinophyceae) and the description of a new species, Ostreopsis rhodesae sp. nov., from a subtropical Australian lagoon.
Publisher: Elsevier BV
Date: 12-2016
DOI: 10.1016/J.HAL.2016.11.004
Abstract: 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 ersity and distribution of species of the benthic dinoflagellate Ostreopsis is one ex le, 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.
The Genetic Basis of Toxin Biosynthesis in Dinoflagellates.
Publisher: MDPI AG
Date: 29-07-2019
DOI: 10.3390/MICROORGANISMS7080222
Abstract: In marine ecosystems, dinoflagellates can become highly abundant and even dominant at times, despite their comparatively slow growth rates. One factor that may play a role in their ecological success is the production of complex secondary metabolite compounds that can have anti-predator, allelopathic, or other toxic effects on marine organisms, and also cause seafood poisoning in humans. Our knowledge about the genes involved in toxin biosynthesis in dinoflagellates is currently limited due to the complex genomic features of these organisms. Most recently, the sequencing of dinoflagellate transcriptomes has provided us with valuable insights into the biosynthesis of polyketide and alkaloid-based toxin molecules in dinoflagellate species. This review synthesizes the recent progress that has been made in understanding the evolution, biosynthetic pathways, and gene regulation in dinoflagellates with the aid of transcriptomic and other molecular genetic tools, and provides a pathway for future studies of dinoflagellates in this exciting omics era.
Both modular and single-domain Type I polyketide synthases are expressed in the brevetoxin-producing dinoflagellate, Karenia brevis (Dinophyceae).
Publisher: Wiley
Date: 03-11-2017
DOI: 10.1111/JPY.12586
Morphology and phylogenetics of benthic prorocentrum species (Dinophyceae) from tropical Northwestern Australia
Publisher: MDPI AG
Date: 30-09-2019
Abstract: Approximately 70 species of Prorocentrum are known, of which around 30 species are associated with benthic habitats. Some produce okadaic acid (OA), dinophysistoxin (DTX) and their derivatives, which are involved in diarrhetic shellfish poisoning. In this study, we isolated and characterized Prorocentrum concavum and P. malayense from Broome in north Western Australia using light and scanning electron microscopy as well as molecular sequences of large subunit regions of ribosomal DNA, marking the first record of these species from Australian waters. The morphology of the motile cells of P. malayense was similar to P. concavum in the light microscopy, but differed by the smooth thecal surface, the pore pattern and the production of mucous stalk-like structures and a hyaline sheath around the non-motile cells. P. malayense could also be differentiated from other closely related species, P. leve and P. foraminosum, despite the similarity in thecal surface and pore pattern, by its platelet formula and morphologies. We tested the production of OA and DTXs from both species, but found that they did not produce detectable levels of these toxins in the given culturing conditions. This study aids in establishing more effective monitoring of potential harmful algal taxa in Australian waters for aquaculture and recreational purposes.
Correction: McLennan et al. Assessing the Use of Molecular Barcoding and qPCR for Investigating the Ecology of Prorocentrum minimum (Dinophyceae), a Harmful Algal Species. Microorganisms 2021, 9, 510
Publisher: MDPI AG
Date: 26-09-2022
DOI: 10.3390/MICROORGANISMS10101906
Abstract: The authors wish to make the following corrections to this paper [...]
Functional significance of phylogeographic structure in a toxic benthic marine microbial eukaryote over a latitudinal gradient along the East Australian Current
Publisher: Wiley
Date: 21-05-2020
DOI: 10.1002/ECE3.6358
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.
Publisher: Wiley
Date: 12-03-2004
When naked became armored: An eight-gene phylogeny reveals monophyletic origin of theca in dinoflagellates
Publisher: Public Library of Science (PLoS)
Date: 19-11-2012
Ankistrodinium armigerum sp. nov. (Dinophyceae), a new species of heterotrophic marine sand-dwelling dinoflagellate from Japan and Australia
Publisher: Wiley
Date: 04-03-2014
DOI: 10.1111/PRE.12048
Temperature variability interacts with mean temperature to influence the predictability of microbial phenotypes.
Publisher: Wiley
Date: 20-07-2022
DOI: 10.1111/GCB.16330
Abstract: Despite their relatively high thermal optima ( T opt ), tropical taxa may be particularly vulnerable to a rising baseline and increased temperature variation because they live in relatively stable temperatures closer to their T opt . We examined how microbial eukaryotes with differing thermal histories responded to temperature fluctuations of different litudes (0 control, ±2, ±4°C) around mean temperatures below or above their T opt . Cosmopolitan dinoflagellates were selected based on their distinct thermal traits and included two species of the same genus (tropical and temperate Coolia spp.), and two strains of the same species maintained at different temperatures for generations (tropical Amphidinium massartii control temperature and high temperature, CT and HT, respectively). There was a universal decline in population growth rate under temperature fluctuations, but strains with narrower thermal niche breadth (temperate Coolia and HT) showed ~10% greater reduction in growth. At suboptimal mean temperatures, cells in the cool phase of the fluctuation stopped iding, fixed less carbon (C) and had enlarged cell volumes that scaled positively with elemental C, N, and P and C:Chlorophyll‐ a . However, at a supra‐optimal mean temperature, fixed C was directed away from cell ision and novel trait combinations developed, leading to greater phenotypic ersity. At the molecular level, heat‐shock proteins, and chaperones, in addition to transcripts involving genome rearrangements, were upregulated in CT and HT during the warm phase of the supra‐optimal fluctuation (30 ± 4°C), a stress response indicating protection. In contrast, the tropical Coolia species upregulated major energy pathways in the warm phase of its supra‐optimal fluctuation (25 ± 4°C), indicating a broadscale shift in metabolism. Our results demonstrate ergent effects between taxa and that temporal variability in environmental conditions interacts with changes in the thermal mean to mediate microbial responses to global change, with implications for biogeochemical cycling.
9. Gambierdiscus, the cause of ciguatera fish poisoning: an increased human health threat influenced by climate change
Publisher: DE GRUYTER
Date: 14-08-2015
Biosynthesis of toxic naturally-occurring seafood contaminants
Publisher: Elsevier BV
Date: 08-2010
DOI: 10.1016/J.TOXICON.2009.09.001
Abstract: 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 characterization of the genes encoding the producing organism's biosynthetic machinery. Feeding studies key to our understanding of a particular toxin's biosynthesis, such as the incorporation 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.
Ocean urea fertilization for carbon credits poses high ecological risks
Publisher: Elsevier BV
Date: 06-2008
Gene expression and molecular evolution of sxtA4 in a saxitoxin producing dinoflagellate Alexandrium catenella
Publisher: Elsevier BV
Date: 12-2014
DOI: 10.1016/J.TOXICON.2014.09.015
Abstract: Dinoflagellates of the genus Alexandrium produce the neurotoxin saxitoxin (STX), responsible for paralytic shellfish poisoning (PSP) and accumulates in marine invertebrates. The recent identification of STX biosynthesis genes allowed us to investigate the expression of sxtA4 at different growth stages in Alexandrium catenella Group IV. We found no significant differences in expression of sxtA4, despite significant differences in STX levels at different growth stages (P < 0.023). Three reference genes were tested for normalisation: actin, cytochrome b (cob), and the large subunit ribosomal RNA (LSU rDNA). cob was most stably expressed but the combination of two reference genes, actin and cob, resulted in the best stability factor. Most genomic sequences of sxtA4 from A. catenella were in a clade that included sequences from Alexandrium fundyense Group I, however, one paralogue was not related to the others, suggesting recombination or lateral transfer. A comparison of the sxtA4 cDNA sequences with genomic DNA sequences indicated the possibility of transcript editing and the preferential transcription of certain genomic DNA loci. The results show that, in dinoflagellates, post-transcriptional mechanisms play a major role in the regulation of saxitoxin biosynthesis.
Detecting environmental change: Transient receptor potential ion channels control thermoregulatory behaviour in reptiles
Publisher: Elsevier BV
Date: 07-2008
Sexual reproduction and genetic polymorphism within the cosmopolitan marine diatom Pseudo-nitzschia pungens.
Publisher: Springer Science and Business Media LLC
Date: 30-06-2020
DOI: 10.1038/S41598-020-67547-9
Abstract: Different clades belonging to the cosmopolitan marine diatom Pseudo-nitzschia pungens appear to be present in different oceanic environments, however, a ‘hybrid zone’, where populations of different clades interbreed, has also been reported. Many studies have investigated the sexual reproduction of P. pungens, focused on morphology and life cycle, rather than the role of sexual reproduction in mixing the genomes of their parents. We carried out crossing experiments to determine the sexual compatibility/incompatibility between different clades of P. pungens , and examined the genetic polymorphism in the ITS2 region. Sexual reproduction did not occur only between clades II and III under any of experimental temperature conditions. Four offspring strains were established between clade I and III successfully. Strains established from offspring were found interbreed with other offspring strains as well as viable with their parental strains. We confirmed the hybrid sequence patterns between clades I and III and found novel sequence types including polymorphic single nucleotide polymorphisms (SNPs) in the offspring strains. Our results implicate that gene exchange and mixing between different clades are still possible, and that sexual reproduction is a significant ecological strategy to maintain the genetic ersity within this diatom species.
{WITHDRAWN}: Gene expression and molecular evolution of {sxtA}4 in a saxitoxin producing dinoflagellate Alexandrium catenella
Publisher: Elsevier BV
Date: 07-2014
DOI: 10.1016/J.TOXICON.2014.07.003
Abstract: This article has been withdrawn at the request of the authors and editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at ocate/withdrawalpolicy.
Alexandrium diversaporum sp. nov., a new non-saxitoxin producing species: Phylogeny, morphology and sxtA genes
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.HAL.2013.09.005
Abstract: Species of the PST producing planktonic marine dinoflagellate genus Alexandrium have been intensively scrutinised, and it is therefore surprising that new taxa can still be found. Here we report a new species, Alexandrium ersaporum nov. sp., isolated from spherical cysts found at two sites in Tasmania, Australia. This species differs in its morphology from all previously reported Alexandrium species, possessing a unique combination of morphological features: the presence of 2 size classes of thecal pores on the cell surface, a medium cell size, the size and shape of the 6″, 1', 2⁗ and Sp plates, the lack of a ventral pore, a lack of anterior and posterior connecting pores, and a lack of chain formation. We determined the relationship of the two strains to other species of Alexandrium based on an alignment of concatenated SSU-ITS1, 5.8S, ITS2 and partial LSU ribosomal RNA sequences, and found A. ersaporum to be a sister group to Alexandrium leei with high support. A. leei shares several morphological features, including the relative size and shapes of the 6″, 1', 2⁗ and Sp plates and the fact that some strains of A. leei have two size classes of thecal pores. We examined A. ersaporum strains for saxitoxin production and found them to be non-toxic. The species lacked sequences for the domain A4 of sxtA, as has been previously found for non-saxitoxin producing species of Alexandrium.
Phylogenetic study of Gymnodinium dorsalisulcum comb. nov. from tropical Australian coastal waters (Dinophyceae)
Publisher: Wiley
Date: 24-04-2007
A reinvestigation of saxitoxin production and sxtA in the 'non-toxic' Alexandrium tamarense Group V clade
Publisher: Elsevier BV
Date: 06-2012
Development of a quantitative PCR assay for the detection and enumeration of a potentially ciguatoxin-producing dinoflagellate, Gambierdiscus lapillus (Gonyaulacales, Dinophyceae)
Publisher: Cold Spring Harbor Laboratory
Date: 08-02-2019
DOI: 10.1101/544247
Abstract: Ciguatera fish poisoning is an illness contracted through the ingestion of seafood containing ciguatoxins. It is prevalent in tropical regions worldwide, including in Australia. Ciguatoxins are produced by some species of Gambierdiscus. Therefore, screening of Gambierdiscus species identification through quantitative PCR (qPCR), along with the determination of species toxicity, can be useful in monitoring potential ciguatera risk in these regions. In Australia, the identity, distribution and abundance of ciguatoxin producing Gambierdiscus spp. is largely unknown. In this study we developed a rapid qPCR assay to quantify the presence and abundance of Gambierdiscus lapillus , a likely ciguatoxic species. We assessed the specificity and efficiency of the qPCR assay. The assay was tested on 25 environmental s les from the Heron Island reef in the southern Great Barrier Reef, a ciguatera endemic region, in triplicate to determine the presence and patchiness of these species across s les from Chnoospora sp., Padina sp. and Sargassum macroalgal hosts. Ciguatera fish poisoning is a human disease contracted by ingesting seafood contaminated with a group of neurotoxins. The group of neurotoxins, named ciguatoxins, are synthesised by species of single celled marine algae from the genus Gambierdiscus. Ciguatera fish poisoning occurs worldwide, particularly in tropical nations. Pacific Island nations are disproportionately impacted, and this impact is predicted to increase as the effects of climate change unfold. Few effective monitoring and mitigation strategies exist for ciguatera fish poisoning, and reporting rates of the disease are estimated to be approximately 20% at best. A global ciguatera strategy was developed by a group of researchers coordinated by UNESCO’s Intergovernmental Oceanographic Commission to characterise the cause and mode of action of ciguatera fish poisoning, as a matter of urgency. In this study, we designed a qPCR assay to detect a species of microalgae, Gambierdiscus lapillus. Gambierdiscus lapillus produces compounds with ciguatoxin-like properties, which may lead to ciguatoxin uptake in fish in the Australian region. This assay was sensitive and able to detect the presence of Gambierdiscus lapillus in a range of environmental s les from the Great Barrier Reef region, Australia.
Ostreopsis Schmidt and Coolia Meunier (Dinophyceae, Gonyaulacales) from Cook Islands and Niue (South Pacific Ocean), including description of Ostreopsis tairoto sp. nov.
Publisher: Springer Science and Business Media LLC
Date: 22-02-2023
DOI: 10.1038/S41598-023-29969-Z
Abstract: It is important to decipher the ersity and distribution of benthic dinoflagellates, as there are many morphologically indistinct taxa that differ from one another in production of potent toxins. To date, the genus Ostreopsis comprises twelve described species, of which seven are potentially toxic and produce compounds presenting a threat to human and environmental health. In this study, isolates previously identified as “ Ostreopsis sp. 3” were s led from the area where it was first reported, Rarotonga, Cook Islands, and have been taxonomically and phylogenetically characterised as Ostreopsis tairoto sp. nov. Phylogenetically, the species is closely related to “ Ostreopsis sp. 8”, O. mascarenensis , “ O . sp. 4”, O. fattorussoi, O. rhodesiae and O . cf. siamensis . Previously, it was considered a part of the O . cf. ovata complex but can be distinguished from O . cf. ovata based on the small pores identified on this study, and from O. fattorussoi and O. rhodesiae based on relative lengths of the 2′ plates. No known palytoxin -like compounds were detected in strains investigated in this study. Strains of O. lenticularis, Coolia malayensis and C. tropicalis were also identified and described. This study advances our knowledge of biogeography, distribution, and toxins of Ostreopsis and Coolia species.
Mapping the development of a Dinophysis bloom in a shellfish aquaculture area using a novel molecular qPCR assay.
Publisher: Elsevier BV
Date: 07-2022
DOI: 10.1016/J.HAL.2022.102253
Abstract: Diarrhetic shellfish toxins produced by certain species of the marine dinoflagellate Dinophysis can accumulate in shellfish in high concentrations, representing a significant food safety issue worldwide. This risk is routinely managed by monitoring programs in shellfish producing areas, however the methods used to detect these harmful marine microbes are not usually automated nor conducted onsite, and are often expensive and require specialized expertise. Here we designed a quantitative real-time polymerase chain reaction (qPCR) assay based on the ITS-5.8S ribosomal region of Dinophysis spp. and evaluated its specificity, efficiency, and sensitivity to detect species belonging to this genus. We designed and tested twenty sets of primers pairs using three species of Dinophysis - D. caudata, D. fortii and D. acuminata. We optimized a qPCR assay using the primer pair that sufficiently lified each of the target species (Dacu_11F/Dacu_11R), and tested this assay for cross-reactivity with other dinoflagellates and diatoms in the laboratory (11 species) and in silico 8 species (15 strains) of Dinophysis, 3 species of Ornithocercus and 2 species of Phalacroma. The qPCR assay returned efficiencies of 92.4% for D. caudata, 91.3% for D fortii, and 91.5% for D. acuminata, while showing no cross-reactivity with other phytoplankton taxa. Finally, we applied this assay to a D. acuminata bloom which occurred in an oyster producing estuary in south eastern Australia, and compared cell numbers inferred by qPCR to those determined by microscopy counts (max abund. ∼6.3 × 10
Distribution of the genus Alexandrium (Halim) and paralytic shellfish toxins along the coastline of New South Wales, Australia
Publisher: Elsevier BV
Date: 07-2013
DOI: 10.1016/J.MARPOLBUL.2013.04.009
Abstract: 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 s les 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.
Response of planktonic microbial assemblages to disturbance in an urban sub-tropical estuary.
Publisher: Elsevier BV
Date: 09-2023
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.
Publisher: Elsevier BV
Date: 10-2017
Genetic diversity, morphological uniformity and polyketide production in dinoflagellates (Amphidinium, Dinoflagellata)
Publisher: Public Library of Science (PLoS)
Date: 04-06-2012
Genomic Contributions to Understanding the Evolution of Red Algal Plastids and Pigment Biosynthesis
Publisher: Springer Netherlands
Date: 2010
4. Alexandrium spp.: genetic and ecological factors influencing saxitoxin production and proliferation
Publisher: DE GRUYTER
Date: 14-08-2015
Evolution and distribution of saxitoxin biosynthesis in dinoflagellates
Publisher: MDPI AG
Date: 08-08-2013
DOI: 10.3390/MD11082814
Bloom drivers of the potentially harmful dinoflagellate Prorocentrum minimum (Pavillard) Schiller in a south eastern temperate Australian estuary
Publisher: Elsevier BV
Date: 12-2018
Improving the analysis of dinoflagellate phylogeny based on rDNA
Publisher: Elsevier BV
Date: 11-2005
DOI: 10.1016/J.PROTIS.2005.05.003
Abstract: Phylogenetic studies of dinoflagellates are often conducted using rDNA sequences. In analyses to date, the monophyly of some of the major lineages of dinoflagellates remain to be demonstrated. There are several reasons for this uncertainty, one of which may be the use of models of evolution that may not closely fit the data. We constructed and examined alignments of SSU and partial LSU rRNA along with a concatenated alignment of the two molecules. The alignments showed several characteristics that may confound phylogeny reconstruction: paired helix (stem) regions that contain non-independently evolving sites, high levels of compositional heterogeneity among some of the sequences, high levels of incompatibility (homoplasy), and rate heterogeneity among sites. Taking into account these confounding factors, we analysed the data and found that the Gonyaulacales, a well-supported clade, may be the most recently erged order. Other supported orders were, in the analysis based on SSU, the Suessiales and the Dinophysiales however, the Gymnodiniales and Prorocentrales appeared to be polyphyletic. The Peridiniales without Heterocapsa species appeared as a monophyletic group in the analysis based on LSU however, the support was low. The concatenated alignment did not provide a better phylogenetic resolution than the single gene alignments.
Toxicology of gambierdiscus spp. (dinophyceae) from tropical and temperate Australian waters
Publisher: MDPI AG
Date: 2018
DOI: 10.3390/MD16010007
Environmental impact assessment including indirect effects - A case study using input-output analysis
Publisher: Elsevier BV
Date: 05-2003
Diarrhetic Shellfish Toxin Monitoring in Commercial Wild Harvest Bivalve Shellfish in New South Wales, Australia
Publisher: MDPI AG
Date: 30-10-2018
Abstract: An end-product market survey on biotoxins in commercial wild harvest shellfish (Plebidonax deltoides, Katelysia spp., Anadara granosa, Notocallista kingii) during three harvest seasons (2015–2017) from the coast of New South Wales, Australia found 99.38% of s les were within regulatory limits. Diarrhetic shellfish toxins (DSTs) were present in 34.27% of 321 s les but only in pipis (P. deltoides), with two s les above the regulatory limit. Comparison of these market survey data to s les (phytoplankton in water and biotoxins in shellfish tissue) collected during the same period at wild harvest beaches demonstrated that, while elevated concentrations of Dinophysis were detected, a lag in detecting bloom events on two occasions meant that wild harvest shellfish with DSTs above the regulatory limit entered the marketplace. Concurrently, data (phytoplankton and biotoxin) from Sydney rock oyster (Saccostrea glomerata) harvest areas in estuaries adjacent to wild harvest beaches impacted by DSTs frequently showed elevated Dinophysis concentrations, but DSTs were not detected in oyster s les. These results highlighted a need for distinct management strategies for different shellfish species, particularly during Dinophysis bloom events. DSTs above the regulatory limit in pipis s led from the marketplace suggested there is merit in looking at options to strengthen the current wild harvest biotoxin management strategies.
Genomic copy number variability at the genus, species and population levels impacts in situ ecological analyses of dinoflagellates and harmful algal blooms
Publisher: Springer Science and Business Media LLC
Date: 08-07-2023
DOI: 10.1038/S43705-023-00274-0
Abstract: The application of meta-barcoding, qPCR, and metagenomics to aquatic eukaryotic microbial communities requires knowledge of genomic copy number variability (CNV). CNV may be particularly relevant to functional genes, impacting dosage and expression, yet little is known of the scale and role of CNV in microbial eukaryotes. Here, we quantify CNV of rRNA and a gene involved in Paralytic Shellfish Toxin (PST) synthesis ( sxtA4 ), in 51 strains of 4 Alexandrium (Dinophyceae) species. Genomes varied up to threefold within species and ~7-fold amongst species, with the largest ( A. pacificum , 130 ± 1.3 pg cell −1 /~127 Gbp) in the largest size category of any eukaryote. Genomic copy numbers (GCN) of rRNA varied by 6 orders of magnitude amongst Alexandrium (10 2 – 10 8 copies cell −1 ) and were significantly related to genome size. Within the population CNV of rRNA was 2 orders of magnitude (10 5 – 10 7 cell −1 ) in 15 isolates from one population, demonstrating that quantitative data based on rRNA genes needs considerable caution in interpretation, even if validated against locally isolated strains. Despite up to 30 years in laboratory culture, rRNA CNV and genome size variability were not correlated with time in culture. Cell volume was only weakly associated with rRNA GCN (20–22% variance explained across dinoflagellates, 4% in Gonyaulacales). GCN of sxtA4 varied from 0–10 2 copies cell −1 , was significantly related to PSTs (ng cell −1 ), displaying a gene dosage effect modulating PST production. Our data indicate that in dinoflagellates, a major marine eukaryotic group, low-copy functional genes are more reliable and informative targets for quantification of ecological processes than unstable rRNA genes.
Phenotypic trait variability as an indication of adaptive capacity in a cosmopolitan marine diatom.
Publisher: Wiley
Date: 03-11-2021
Abstract: Determining the adaptive capacity of marine phytoplankton is important in predicting changes in phytoplankton responses to ocean warming. Phytoplankton may consist of high levels of standing phenotypic and genetic variability, the basis of rapid evolution however, few studies have quantified trait variability within and amongst closely related diatom species. Using 35 clonal cultures of the ubiquitous marine diatom Leptocylindrus isolated from six locations, spanning 2000 km of the south‐eastern Australian coastline, we found evidence of significant intraspecific morphological and metabolic trait variability, which for 8 of 9 traits (growth rate, biovolume, C:N, silica deposition, silica incorporation rate, chl‐a, and photosynthetic efficiency under dark adapted, growth irradiance, and high‐light adaptation) were greater within a species than between species. Moreover, only two traits revealed a latitudinal trend with strains isolated from lower latitudes showing significantly higher silicification rates and protein:lipid content compared to their higher latitude counterparts. These data mirror recent studies on diatom intraspecific genetic ersity, which has found comparable levels of genetic ersity at a single site to those thousands of kilometres apart, and provide evidence of a functional role of diatom ersity that will allow for rapid adaptation via ecological selection on standing variation in response to changing conditions.
The taxonomic significance of species that have only been observed once: The genus Gymnodinium (dinoflagellata) as an example
Publisher: Public Library of Science (PLoS)
Date: 30-08-2012
Thermal acclimation and regulation of metabolism in a reptile (Crocodylus porosus): the importance of transcriptional mechanisms and membrane composition
Publisher: University of Chicago Press
Date: 11-2009
DOI: 10.1086/605955
Abstract: 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 (PPARgamma) and its coactivator PPARgamma coactivator 1 alpha (PGC-1alpha), 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-1alpha and PPARgamma 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-1alpha and PPARgamma in a reptile indicate that the mechanisms that regulate metabolism are conserved among vertebrates.
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
Publisher: Wiley
Date: 09-2004
Morphology and molecular phylogeny of Ankistrodinium Gen. Nov (Dinophyceae), a new genus of marine sand-dwelling dinoflagellates formerly classified within Amphidinium
Publisher: Wiley
Date: 25-06-2012
DOI: 10.1111/J.1529-8817.2012.01198.X
Abstract: The classical athecate dinoflagellate genera (Amphidinium, Gymnodinium, Gyrodinium) have long been recognized to be polyphyletic. Amphidinium sensu lato is the most erse of all marine benthic dinoflagellate genera however, following the redefinition of this genus ∼100 species remain now of uncertain or unknown generic affiliation. In an effort to improve our taxonomic and phylogenetic understanding of one of these species, namely Amphidinium semilunatum, we re-investigated organisms from several distant sites around the world using light and scanning electron microscopy and molecular phylogenetic methods. Our results enabled us to describe this species within a new heterotrophic genus, Ankistrodinium. Cells of A. semilunatum were strongly laterally flattened, rounded-quadrangular to oval in lateral view, and possessed a small asymmetrical epicone. The sulcus was wide and characteristically deeply incised on the hypocone running around the antapex and reaching the dorsal side. The straight acrobase with hook-shaped end started at the sulcal extension and continued onto the epicone. The molecular phylogenetic results clearly showed that A. semilunatum is a distinct taxon and is only distantly related to species within the genus Amphidinium sensu stricto. The nearest sister group to Ankistrodinium could not be reliably determined.
The diatom genus Pseudo-nitzschia (Bacillariophyceae) in New South Wales, Australia: morphotaxonomy, molecular phylogeny, toxicity, and distribution
Publisher: Wiley
Date: 02-07-2013
DOI: 10.1111/JPY.12087
Abstract: Species belonging to the potentially harmful diatom genus Pseudo-nitzschia, isolated from 16 localities (31 s ling 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 chromatography-mass 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 s les, 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.
Phylogenetic study of benthic, spine-bearing prorocentroids, including Prorocentrum fukuyoi sp. nov.
Publisher: Wiley
Date: 24-04-2007
A feeding study to probe the uptake of Maitotoxin by snapper (Pagrus auratus)
Publisher: Elsevier BV
Date: 07-2014
A new Gambierdiscus species (Dinophyceae) from Rarotonga, Cook Islands: Gambierdiscus cheloniae sp. nov
Publisher: Elsevier BV
Date: 12-2016
DOI: 10.1016/J.HAL.2016.10.006
Abstract: Ciguatera fish poisoning (CFP) has been reported for many years in Rarotonga, Cook Islands, and has had the world's highest reported incidence of this illness for the last 20 years. Following intensive s ling to understand the distribution of the causative organisms of CFP, an undescribed Gambierdiscus species was isolated from the Rarotongan lagoon. Gambierdiscus cheloniae sp. nov. has the common Gambierdiscus Kofoidian plate formula (except for a variability in the number of precingular plates in aberrant cells): Po, 3', 6″ (7″), 6C?, 6 or 7S, 5'″, 1p and 2″″. The 2' plate is hatchet shaped and the dorsal end of 1p is pointed and the relatively narrow 1p plate. Morphologically G. cheloniae is similar to the genetically closely related species G. pacificus, G. toxicus and G. belizeanus, although smaller (depth and length) than G. toxicus. The apical pore plate varies from those of G. belizeanus and G. pacificus, which are shorter and narrower, and from G. toxicus, which is larger. G. cheloniae also differs from G. pacificus in the shape of the 2' plate. The description of this new species is supported by phylogenetic analyses using three different gene regions. G. cheloniae produced the putative maitotoxin-3 analogue, MTX-3, but neither maitotoxin or monitored ciguatoxin. Extracts of G. cheloniae were shown to be highly toxic to mice by intraperitoneal (i.p.) injection, although they were less toxic by gavage. It is possible that this species produces toxins other than putative MTX-3.
Population ecology of Noctiluca scintillans Macartney, a red-tide-forming dinoflagellate
Publisher: CSIRO Publishing
Date: 1999
DOI: 10.1071/MF98052
Abstract: 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 ( cells L–1) occurred in spring and again in late summer, and low concentrations ( cells L–1) 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 L–1. During the spring bloom, Noctiluca cells from coastal stations had small diameters (340–450 µm), a high nutritional status and a high proportion of ision 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 ( cells L–1), and were characterized by large diameters (400–1200 µm), 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).
Recent Trends in Marine Phycotoxins from Australian Coastal Waters
Publisher: MDPI AG
Date: 09-02-2017
DOI: 10.3390/MD15020033
Impacts of harmful algal blooms on marine aquaculture in a low-carbon future.
Publisher: Elsevier BV
Date: 12-2021
DOI: 10.1016/J.HAL.2021.102143
Abstract: The IPCC Special Report on Global Warming of 1.5 °C highlights the potential for dietary shifts to reduce greenhouse gas emissions from livestock. Reductions in the consumption of terrestrial animal protein require increases in the consumption of other food categories, to maintain food security, balanced dietary patterns, and protein intake. Aquaculture has long been suggested as one way to meet future food security needs, and marine and estuarine aquaculture in particular is associated with comparatively low greenhouse gas emissions. However, marine and freshwater aquaculture is affected by factors including harmful algal blooms (HABs), which have been increasingly documented around the world, correlated to increases in worldwide aquaculture. In this study, we applied a global multi-region input-output model to capture the direct effects as well as the indirect and induced effects HABs might pose to a global dietary transition from terrestrial livestock to increased seafood consumption from marine and estuarine aquaculture sources. We found that marine and estuarine aquaculture has a substantial potential to replace meat consumption from terrestrial livestock sources, as increases in CO
Are Prorocentroid Dinoflagellates Monophyletic? A Study of 25 Species Based on Nuclear and Mitochondrial Genes
Publisher: Elsevier BV
Date: 05-2009
DOI: 10.1016/J.PROTIS.2008.12.004
Abstract: 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.
Geographical distribution, molecular and toxin diversity of the dinoflagellate species Gambierdiscus honu in the Pacific region.
Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1016/J.HAL.2022.102308
Abstract: An increase in cases of ciguatera poisoning (CP) and expansion of the causative species in the South Pacific region highlight the need for baseline data on toxic microalgal species to help identify new areas of risk and manage known hot spots. Gambierdiscus honu is a toxin producing and potential CP causing dinoflagellate species, first described in 2017. Currently no high-resolution geographical distribution, intraspecific genetic variation or toxin production ersity data is available for G. honu. This research aimed to further characterize G. honu by investigating its distribution using species-specific real-time polymerase chain reaction assays at 25 sites in an area spanning ∼8000 km of the Coral Sea/Pacific Ocean, and assessing intraspecific genetic variation, toxicity and toxin production of isolated strains. Assessment of genetic variation of the partial rRNA operon of isolates demonstrated no significant intraspecific population structure, in addition to a lack of adherence to isolation by distance (IBD) model of evolution. The detected distribution of G. honu in the Pacific region was within the expected tropical to temperate latitudinal ranges of 10° to -30° and extended from Australia to French Polynesia. In the lipophilic fractions, the neuroblastoma cell-based assay (CBA-N2a) showed no ciguatoxin (CTX)-like activity for nine of the 10 isolates, and an atypical pattern for CAWD233 isolate which showed cytotoxic activity in OV- and OV+ conditions. In the same way, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis confirmed no Pacific-CTXs (CTX-3B, CTX-3C, CTX-4A, CTX-4B) were produced by the ten strains. The CBA-N2a assessment of the hydrophilic fractions showed moderate to high cytotoxicity in both OV- and OV+ condition for all the strains showing a cytotoxic profile similar to that of gambierone. Indeed, this study is the first to show the cytotoxic activity of gambierone on mouse neuroblastoma cells while no cytotoxicity was observed when 44-MG was analysed at the same concentrations using the CBA-N2a. Analysis of the hydrophilic via LC-MS/MS confirmed production of gambierone in all isolates, ranging from 2.1 to 38.1 pg/cell, with 44-methylgambierone (44-MG) also produced by eight of the isolates, ranging from 0.3 to 42.9 pg/cell. No maitotoxin-1 was detected in any of the isolates. Classification of the G. honu strains according to the quantities of gambierone produced aligned with the classification of their cytotoxicity using the CBA-N2a. Finally, no maitotoxin-1 (MTX) was detected in any of the isolates. This study shows G. honu is widely distributed within the Pacific region with no significant intraspecific population structure present. This aligns with the view of microalgal populations as global metapopulations, however more in-depth assessment with other genetic markers could detect further structure. Toxicity ersity across 10 isolates assessed did not display any geographical patterns.
Assessing the Use of Molecular Barcoding and qPCR for Investigating the Ecology of Prorocentrum minimum (Dinophyceae), a Harmful Algal Species
Publisher: MDPI AG
Date: 28-02-2021
DOI: 10.3390/MICROORGANISMS9030510
Abstract: Prorocentrum minimum is a species of marine dinoflagellate that occurs worldwide and can be responsible for harmful algal blooms (HABs). Some studies have reported it to produce tetrodotoxin however, results have been inconsistent. qPCR and molecular barcoding ( licon sequencing) using high-throughput sequencing have been increasingly applied to quantify HAB species for ecological analyses and monitoring. Here, we isolated a strain of P. minimum from eastern Australian waters, where it commonly occurs, and developed and validated a qPCR assay for this species based on a region of ITS rRNA in relation to abundance estimates from the cultured strain as determined using light microscopy. We used this tool to quantify and examine ecological drivers of P. minimum in Botany Bay, an estuary in southeast Australia, for over ~14 months in 2016–2017. We compared abundance estimates using qPCR with those obtained using molecular barcoding based on an 18S rRNA licon. There was a significant correlation between the abundance estimates from licon sequencing and qPCR, but the estimates from light microscopy were not significantly correlated, likely due to the counting method applied. Using licon sequencing, ~600 unique actual sequence variants (ASVs) were found, much larger than the known phytoplankton ersity from this region. P. minimum abundance in Botany Bay was found to be significantly associated with lower salinities and higher dissolved CO2 levels.
Corrigendum: A database of marine phytoplankton abundance, biomass and species composition in Australian waters.
Publisher: Springer Science and Business Media LLC
Date: 06-03-2024
Abstract: Scientific Data 3:160043 doi:10.1038/sdata.2016.43 (2016) Published 21 Jun 2016 Updated 6 Dec 2016 A series of errors in our database were brought to our attention by readers, and have been corrected in an updated version of this database, which is accessible via the AODN at the following link: portal.
First report of the potentially toxic marine diatom Pseudo-nitzschia simulans (Bacillariophyceae) from the East Australian Current
Publisher: Wiley
Date: 24-03-2020
DOI: 10.1111/PRE.12421
Transcriptomics and microbial eukaryote diversity: a way forward
Publisher: Elsevier BV
Date: 12-2012
The benthic dinoflagellate genus Amphidinium in south-eastern Australian waters, including three new species
Publisher: Informa UK Limited
Date: 05-2002
First reports of Pseudo-nitzschia micropora and P. hasleana (Bacillariaceae) from the Southern Hemisphere: Morphological, molecular and toxicological characterization
Publisher: Wiley
Date: 03-06-2013
DOI: 10.1111/PRE.12020
The first report of the potentially harmful diatom Pseudo-nitzschia caciantha from Australian coastal waters.
Publisher: Wiley
Date: 12-09-2016
DOI: 10.1111/PRE.12142
Fifteen years of Pseudo-nitzschia in an Australian estuary, including the first potentially toxic P. delicatissima bloom in the southern hemisphere
Publisher: Elsevier BV
Date: 05-2020
The microbiome of the cosmopolitan diatom Leptocylindrus reveals significant spatial and temporal variability
Publisher: Frontiers Media SA
Date: 15-11-2018
Warm temperature acclimation impacts metabolism of paralytic shellfish toxins from Alexandrium minutum in commercial oysters.
Publisher: Wiley
Date: 29-05-2015
DOI: 10.1111/GCB.12952
Abstract: 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 loidy 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.
Development of a quantitative PCR assay for the detection and enumeration of a potentially ciguatoxin-producing dinoflagellate, Gambierdiscus lapillus (Gonyaulacales, Dinophyceae)
Publisher: Public Library of Science (PLoS)
Date: 15-11-2019
Novel reptilian uncoupling proteins: molecular evolution and gene expression during cold acclimation
Publisher: The Royal Society
Date: 29-01-2008
Abstract: 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.
Evolutionary distinctiveness of fatty acid and polyketide synthesis in eukaryotes.
Publisher: Springer Science and Business Media LLC
Date: 19-01-2016
Transient receptor potential ion channels control thermoregulatory behaviour in reptiles
Publisher: Public Library of Science (PLoS)
Date: 14-03-2007
Characterization of Gambierdiscus lapillus sp. nov. (Gonyaulacales, Dinophyceae): a new toxic dinoflagellate from the Great Barrier Reef (Australia).
Publisher: Wiley
Date: 30-01-2017
DOI: 10.1111/JPY.12496
Abstract: 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.
Revealing RNA virus diversity and evolution in unicellular algae transcriptomes
Publisher: Cold Spring Harbor Laboratory
Date: 10-05-2021
DOI: 10.1101/2021.05.09.443335
Abstract: Remarkably little is known about the ersity and evolution of RNA viruses in unicellular eukaryotes. We screened a total of 570 transcriptomes from the Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP) project that encompasses a wide ersity of microbial eukaryotes, including most major photosynthetic lineages (i.e. the microalgae). From this, we identified 30 new and ergent RNA virus species, occupying a range of phylogenetic positions within the overall ersity of RNA viruses. Approximately one-third of the newly described viruses comprised single-stranded positive-sense RNA viruses from the order Lenarviricota associated with fungi, plants and protists, while another third were related to the order Ghabrivirales , including members of the protist and fungi-associated Totiviridae . Other viral species showed sequence similarity to positive-sense RNA viruses from the algae-associated Marnaviridae , the double-stranded RNA Partitiviridae , as well as a single negative-sense RNA virus related to the Qinviridae. Importantly, we were able to identify ergent RNA viruses from distant host taxa, revealing the ancestry of these viral families and greatly extending our knowledge of the RNA viromes of microalgal cultures. Both the limited number of viruses detected per s le and the low sequence identity to known RNA viruses imply that additional microalgal viruses exist that could not be detected at the current sequencing depth or were too ergent to be identified using sequence similarity. Together, these results highlight the need for further investigation of algal-associated RNA viruses as well as the development of new tools to identify RNA viruses that exhibit very high levels of sequence ergence.
Diversity, temporal distribution and physiology of the centric diatom Leptocylindrus (Bacillariophyta) from a southern hemisphere upwelling system
Publisher: Informa UK Limited
Date: 10-2016
Thermal adaptation in endotherms: climate and phylogeny interact to determine population-level responses in a wild rat
Publisher: Wiley
Date: 21-11-2012
Role of Modular Polyketide Synthases in the Production of Polyether Ladder Compounds in Ciguatoxin-Producing Gambierdiscus polynesiensis and G. excentricus (Dinophyceae).
Publisher: Wiley
Date: 23-03-2017
DOI: 10.1111/JEU.12405
Abstract: 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.
Proposal to reject the name Gonyaulax catenella (Alexandrium catenella) (Dinophyceae)
Publisher: Wiley
Date: 08-2014
DOI: 10.12705/634.21
Historical accountability and cumulative impacts: the treatment of time in corporate sustainability reporting
Publisher: Elsevier BV
Date: 12-2004
Evolutionary acquisition and loss of saxitoxin biosynthesis in dinoflagellates: the second core gene, sxtG
Publisher: American Society for Microbiology
Date: 04-2013
DOI: 10.1128/AEM.03279-12
Abstract: 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 lified and sequenced. The transcripts contained typical dinoflagellate spliced leader sequences and eukaryotic poly(A) tails. In addition, partial sxtG transcript fragments were lified 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 lified from Alexandrium species not known to synthesize saxitoxin. However, lification 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.
Phylogenetics of Rhinodinium broomeense gen. et sp. nov., a peridinoid, sand-dwelling dinoflagellate (Dinophyceae)
Publisher: Wiley
Date: 11-07-2006
A modified ecological footprint method and its application to Australia
Publisher: Elsevier BV
Date: 05-2001
qPCR Assays for the Detection and Quantification of Multiple Paralytic Shellfish Toxin-Producing Species of Alexandrium.
Publisher: Frontiers Media SA
Date: 18-12-2018
Morphology and molecular phylogeny of Bindiferia gen. nov. (Dinophyceae), a new marine, sand-dwelling dinoflagellate genus formerly classified within Amphidinium
Publisher: Informa UK Limited
Date: 29-10-2021
Taxonomy and phylogeny of the benthic Prorocentrum species (Dinophyceae) - A proposal and review
Publisher: Elsevier BV
Date: 07-2013
Using qPCR and high-resolution sensor data to model a multi-species Pseudo-nitzschia (Bacillariophyceae) bloom in southeastern Australia.
Publisher: Elsevier BV
Date: 08-2021
High abundance of the potentially maitotoxic dinoflagellate Gambierdiscus carpenteri in temperate waters of New South Wales, Australia
Publisher: Elsevier BV
Date: 10-2014
Management of Ciguatoxin Risk in Eastern Australia.
Publisher: MDPI AG
Date: 14-11-2017
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End Date: 09-2018
Amount: $375,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE140100055
Start Date: 2014
End Date: 12-2015
Amount: $290,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE130100019
Start Date: 2013
End Date: 12-2014
Amount: $580,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP110100516
Start Date: 07-2011
End Date: 07-2014
Amount: $115,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP180100001
Start Date: 06-2019
End Date: 06-2023
Amount: $259,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP120103199
Start Date: 2012
End Date: 12-2014
Amount: $230,000.00
Funder: Australian Research Council
View Funded Activity