1
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Ruvindy R, Ajani PA, Ashlin S, Hallegraeff G, Klemm K, Bolch CJ, Ugalde S, Van Asten M, Woodcock S, Tesoriero M, Murray SA. An On-Farm Workflow for Predictive Management of Paralytic Shellfish Toxin-Producing Harmful Algal Blooms for the Aquaculture Industry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:6924-6933. [PMID: 38608723 PMCID: PMC11044886 DOI: 10.1021/acs.est.3c10502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/27/2024] [Accepted: 02/29/2024] [Indexed: 04/14/2024]
Abstract
Paralytic shellfish toxins (PSTs) produced by marine dinoflagellates significantly impact shellfish industries worldwide. Early detection on-farm and with minimal training would allow additional time for management decisions to minimize economic losses. Here, we describe and test a standardized workflow based on the detection of sxtA4, an initial gene in the biosynthesis of PSTs. The workflow is simple and inexpensive and does not require a specialized laboratory. It consists of (1) water collection and filtration using a custom gravity sampler, (2) buffer selection for sample preservation and cell lysis for DNA, and (3) an assay based on a region of sxtA, DinoDtec lyophilized quantitative polymerase chain reaction (qPCR) assay. Water samples spiked with Alexandrium catenella showed a cell recovery of >90% when compared to light microscopy counts. The performance of the lysis method (90.3% efficient), Longmire's buffer, and the DinoDtec qPCR assay (tested across a range of Alexandrium species (90.7-106.9% efficiency; r2 > 0.99)) was found to be specific, sensitive, and efficient. We tested the application of this workflow weekly from May 2016 to 30th October 2017 to compare the relationship between sxtA4 copies L-1 in seawater and PSTs in mussel tissue (Mytilus galloprovincialis) on-farm and spatially (across multiple sites), effectively demonstrating an ∼2 week early warning of two A. catenella HABs (r = 0.95). Our tool provides an early, accurate, and efficient method for the identification of PST risk in shellfish aquaculture.
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Affiliation(s)
- Rendy Ruvindy
- School
of Life Sciences, University of Technology
Sydney, Ultimo 2007, Australia
| | - Penelope A. Ajani
- School
of Life Sciences, University of Technology
Sydney, Ultimo 2007, Australia
| | | | - Gustaaf Hallegraeff
- Institute
for Marine and Antarctic Studies, University
of Tasmania, Hobart 7004, Australia
| | - Kerstin Klemm
- Alfred
Wegener Institute for Polar and Marine Research, 27570 Bremerhaven, Germany
| | - Christopher J. Bolch
- Institute
for Marine and Antarctic Studies, University
of Tasmania, Hobart 7004, Australia
| | - Sarah Ugalde
- Institute
for Marine and Antarctic Studies, University
of Tasmania, Hobart 7004, Australia
- Centre
for Marine Socioecology, University of Tasmania, Hobart 7004, Australia
| | - Mark Van Asten
- Diagnostic
Technology, Belrose 2085, Australia
- School
of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney 2052, Australia
| | - Stephen Woodcock
- School
of Life Sciences, University of Technology
Sydney, Ultimo 2007, Australia
| | - Matthew Tesoriero
- School
of Life Sciences, University of Technology
Sydney, Ultimo 2007, Australia
| | - Shauna A. Murray
- School
of Life Sciences, University of Technology
Sydney, Ultimo 2007, Australia
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2
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Bui QTN, Kim HS, Ki JS. Polyphyletic origin of saxitoxin biosynthesis genes in the marine dinoflagellate Alexandrium revealed by comparative transcriptomics. HARMFUL ALGAE 2024; 134:102620. [PMID: 38705616 DOI: 10.1016/j.hal.2024.102620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/26/2024] [Accepted: 03/15/2024] [Indexed: 05/07/2024]
Abstract
The marine dinoflagellate Alexandrium is known to form harmful algal blooms, and at least 14 species within the genus can produce saxitoxins (STXs). STX biosynthesis genes (sxt) are individually revealed in toxic dinoflagellates; however, the evolutionary history remains controversial. Herein, we determined the transcriptome sequences of toxic Alexandrium (A. catenella and A. pacificum) and non-toxic Alexandrium (A. fraterculus and A. fragae) and characterized their sxt by focusing on evolutionary events and STX production. Comparative transcriptome analysis revealed higher homology of the sxt in toxic Alexandrium than in non-toxic species. Notably, non-toxic Alexandrium spp. were found to have lost two sxt core genes, namely sxtA4 and sxtG. Expression levels of 28 transcripts related to eight sxt core genes showed that sxtA, sxtG, and sxtI were relatively high (>1.5) in the toxic group compared to the non-toxic group. In contrast, the non-toxic group showed high expression levels in sxtU (1.9) and sxtD (1.7). Phylogenetic tree comparisons revealed distinct evolutionary patterns between 28S rDNA and sxtA, sxtB, sxtI, sxtD, and sxtU. However, similar topology was observed between 28S rDNA, sxtS, and sxtH/T. In the sxtB and sxtI phylogeny trees, toxic Alexandrium and cyanobacteria were clustered together, separating from non-toxic species. These suggest that Alexandrium may acquire sxt genes independently via horizontal gene transfer from toxic cyanobacteria and other multiple sources, demonstrating monocistronic transcripts of sxt in dinoflagellates.
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Affiliation(s)
- Quynh Thi Nhu Bui
- Department of Life Science, Sangmyung University, Seoul 03016, South Korea
| | - Han-Sol Kim
- Department of Life Science, Sangmyung University, Seoul 03016, South Korea
| | - Jang-Seu Ki
- Department of Life Science, Sangmyung University, Seoul 03016, South Korea.
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3
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Kim HS, Kim T, Park J, Park TG, Ki JS. Development of saxitoxin biosynthesis gene sxtB-targeted qPCR assay for the quantification of toxic dinoflagellates Alexandrium catenella (group I) and A. pacificum (group IV) occurring in the Korean coast. HARMFUL ALGAE 2024; 134:102603. [PMID: 38705609 DOI: 10.1016/j.hal.2024.102603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 02/07/2024] [Accepted: 02/16/2024] [Indexed: 05/07/2024]
Abstract
Toxic dinoflagellate Alexandrium can produce saxitoxins (STXs) and cause paralytic shellfish poisoning (PSP), and thus they are monitored for environmental safety management. Microscopic discrimination of dinoflagellates is difficult to distinguish between toxic and non-toxic species due to their similar morphology. Meanwhile, an alternative quantitative PCR (qPCR) assay is sensitive, rapid, and cost-effective for harmful species monitoring. Herein, we developed a novel qPCR assay to detect the STXs biosynthesis gene sxtB of Alexandrium catenella and A. pacificum, the leading cause of PSP outbreaks in Asian coasts and worldwide. The newly designed sxtB TaqMan probes target the species without any positive signal in other relative dinoflagellates. Deming regression analysis revealed that the sxtB copy number of A. catenella and A. pacificum was 3.6 and 4.1 copies per cell, respectively. During the blooming periods (April 13th-14th, 2020), only A. catenella cells were detected through the qPCR assay, ranging from 5.0 × 10 to 2.5 × 104 eq cells L-1. In addition, sxtB qPCR quantified more accurately compared to large subunit (LSU) rRNA targeting qPCR assay that overestimate cell density. Besides, the sensitivity of sxtB was higher compared to the microscope when the species were rarely present (5.0 × 102 cells L-1). These suggest that the sxtB qPCR assay can be applied to toxic Alexandrium monitoring in the Korean coast, even in the early stage of bloomings.
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Affiliation(s)
- Han-Sol Kim
- Department of Life Science, Sangmyung University, Seoul 03016, Korea
| | - Taehee Kim
- Department of Life Science, Sangmyung University, Seoul 03016, Korea
| | - Jaeyeon Park
- Environment & Resource Convergence Center, Advanced Institute of Convergence Technologies, Suwon 16229, Korea
| | - Tae Gyu Park
- National Institute of Fisheries Science (NIFS), Busan 46083, Korea
| | - Jang-Seu Ki
- Department of Life Science, Sangmyung University, Seoul 03016, Korea.
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4
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Ruvindy R, Barua A, Bolch CJS, Sarowar C, Savela H, Murray SA. Genomic copy number variability at the genus, species and population levels impacts in situ ecological analyses of dinoflagellates and harmful algal blooms. ISME COMMUNICATIONS 2023; 3:70. [PMID: 37422553 PMCID: PMC10329664 DOI: 10.1038/s43705-023-00274-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 06/18/2023] [Accepted: 06/20/2023] [Indexed: 07/10/2023]
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 (102- 108 copies cell-1) and were significantly related to genome size. Within the population CNV of rRNA was 2 orders of magnitude (105 - 107 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 0-102 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.
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Affiliation(s)
- Rendy Ruvindy
- University of Technology Sydney, School of Life Sciences, Sydney, PO Box 123, Broadway, NSW, 2007, Australia
| | - Abanti Barua
- University of Technology Sydney, School of Life Sciences, Sydney, PO Box 123, Broadway, NSW, 2007, Australia
| | - Christopher J S Bolch
- Institute for Marine & Antarctic Studies, University of Tasmania, Launceston, 7248, TAS, Australia
| | - Chowdhury Sarowar
- Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW, Australia
| | - Henna Savela
- University of Technology Sydney, School of Life Sciences, Sydney, PO Box 123, Broadway, NSW, 2007, Australia
- Finnish Environment Institute, Marine Research Centre, Helsinki, Finland
| | - Shauna A Murray
- University of Technology Sydney, School of Life Sciences, Sydney, PO Box 123, Broadway, NSW, 2007, Australia.
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5
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Ajani PA, Henriquez-Nunez HF, Verma A, Nagai S, Uchida H, Tesoriero MJ, Farrell H, Zammit A, Brett S, Murray SA. Mapping the development of a Dinophysis bloom in a shellfish aquaculture area using a novel molecular qPCR assay. HARMFUL ALGAE 2022; 116:102253. [PMID: 35710205 DOI: 10.1016/j.hal.2022.102253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 05/03/2022] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
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 amplified 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 × 103 and 5.3 × 103 cells L-1 respectively). Novel molecular tools such as qPCR have the potential to be used on-farm, be automated, and provide an early warning for the management of harmful algal blooms.
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Affiliation(s)
- Penelope A Ajani
- University of Technology Sydney, School of Life Sciences, Sydney, PO Box 123, Broadway, NSW 2007, Australia; Food Agility CRC Ltd, 175 Pitt St, Sydney, NSW 2000, Australia.
| | - Hernan F Henriquez-Nunez
- University of Technology Sydney, School of Life Sciences, Sydney, PO Box 123, Broadway, NSW 2007, Australia; Food Agility CRC Ltd, 175 Pitt St, Sydney, NSW 2000, Australia
| | - Arjun Verma
- University of Technology Sydney, School of Life Sciences, Sydney, PO Box 123, Broadway, NSW 2007, Australia; Food Agility CRC Ltd, 175 Pitt St, Sydney, NSW 2000, Australia
| | - Satoshi Nagai
- Coastal and Inland Fisheries Ecosystems Division, Fisheries Technology Institute, Japan Fisheries Research and Education Agency. 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
| | - Hajime Uchida
- Seafood Safety and Technology Division, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
| | - Matthew J Tesoriero
- University of Technology Sydney, School of Life Sciences, Sydney, PO Box 123, Broadway, NSW 2007, Australia; Food Agility CRC Ltd, 175 Pitt St, Sydney, NSW 2000, Australia
| | - Hazel Farrell
- NSW Food Authority, NSW Department of Primary Industries, PO Box 232, Taree 2430, Australia
| | - Anthony Zammit
- NSW Food Authority, NSW Department of Primary Industries, PO Box 232, Taree 2430, Australia
| | - Steve Brett
- Microalgal Services, 308 Tucker Rd, Ormond 3204, Australia
| | - Shauna A Murray
- University of Technology Sydney, School of Life Sciences, Sydney, PO Box 123, Broadway, NSW 2007, Australia; Food Agility CRC Ltd, 175 Pitt St, Sydney, NSW 2000, Australia
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6
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Jean N, Perié L, Dumont E, Bertheau L, Balliau T, Caruana AMN, Amzil Z, Laabir M, Masseret E. Metal stresses modify soluble proteomes and toxin profiles in two Mediterranean strains of the distributed dinoflagellate Alexandrium pacificum. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 818:151680. [PMID: 34793790 DOI: 10.1016/j.scitotenv.2021.151680] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/25/2021] [Accepted: 11/10/2021] [Indexed: 06/13/2023]
Abstract
HABs involving Alexandrium pacificum have been reported in metal-contaminated ecosystems, suggesting that this distributed species adapts to and/or can tolerate the effects of metals. Modifications in soluble proteomes and PST contents were characterized in two Mediterranean A. pacificum strains exposed to mono- or polymetallic stresses (zinc, lead, copper, cadmium). These strains were isolated from two anthropized locations: Santa Giusta Lagoon (Italy, SG C10-3) and the Tarragona seaport (Spain, TAR C5-4F). In both strains, metals primarily downregulated key photosynthesis proteins. Metals also upregulated other proteins involved in photosynthesis (PCP in both strains), the oxidative stress response (HSP 60, proteasome and SOD in SG C10-3; HSP 70 in TAR C5-4F), energy metabolism (AdK in TAR C5-4F), neoglucogenesis/glycolysis (GAPDH and PEP synthase in SG C10-3) and protein modification (PP in TAR C5-4F). These proteins, possibly involved in adaptive proteomic responses, may explain the development of these A. pacificum strains in metal-contaminated ecosystems. The two strains showed different proteomic responses to metals, with SG C10-3 upregulating more proteins, particularly PCP. Among the PSTs, regardless of the metal and the strain studied, C2 and GTX4 predominated, followed by GTX5. Under the polymetallic cocktail, (i) total PSTs, C2 and GTX4 reached the highest levels in SG C10-3 only, and (ii) total PSTs, C2, GTX5 and neoSTX were higher in SG C10-3 than in TAR C5-4F, whereas in SG C10-3 under copper stress, total PSTs, GTX5, GTX1 and C1 were higher than in the controls, revealing variability in PST biosynthesis between the two strains. Total PSTs, C2, GTX4 and GTX1 showed significant positive correlations with PCP, indicating that PST production may be positively related to photosynthesis. Our results showed that the A. pacificum strains adapt their proteomic and physiological responses to metals, which may contribute to their ecological success in highly anthropized areas.
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Affiliation(s)
- Natacha Jean
- Université de Toulon, Aix Marseille Univ, CNRS, IRD, MIO, Toulon, France.
| | - Luce Perié
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University, 30(th) St., New York, NY 10016, USA
| | - Estelle Dumont
- UMR_MD1, Aix-Marseille Univ, U-1261-INSERM, SSA, IRBA, MCT, Marseille, France
| | - Lucie Bertheau
- UMR PAM A 02.102 Procédés Alimentaires et Microbiologiques, Université de Bourgogne Franche-Comté, AgroSup Dijon, esplanade Erasme, 21 000 Dijon, France
| | - Thierry Balliau
- PAPPSO-GQE-Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91 190 Gif-sur-Yvette, France
| | - Amandine M N Caruana
- IFREMER, Phycotoxin Laboratory, rue de l'île d'Yeu, BP 21105, 44 311 Nantes, France
| | - Zouher Amzil
- IFREMER, Phycotoxin Laboratory, rue de l'île d'Yeu, BP 21105, 44 311 Nantes, France
| | - Mohamed Laabir
- Marbec, Univ Montpellier, IRD, Ifremer, CNRS, Montpellier, France
| | - Estelle Masseret
- Marbec, Univ Montpellier, IRD, Ifremer, CNRS, Montpellier, France
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7
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Thi Nhu Bui Q, Kim H, Wang H, Ki JS. Unveiling the genomic structures and evolutionary events of the saxitoxin biosynthetic gene sxtA in the marine toxic dinoflagellate Alexandrium. Mol Phylogenet Evol 2022; 168:107417. [PMID: 35031458 DOI: 10.1016/j.ympev.2022.107417] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 11/24/2021] [Accepted: 12/27/2021] [Indexed: 12/30/2022]
Abstract
Marine dinoflagellates Alexandriumare known to produce saxitoxin (STX) and cause paralytic shellfish poisoning (PSP) which can result in mortality in human. SxtA is considered a core gene for the biosynthesis of STX. However, its gene coding structure and evolutionary history have yet to be fully elucidated. Here, we determined the full-length sequences of sxtA cDNA and genomic coding regions from two toxic dinoflagellates, Alexandrium catenella (LIMS-PS-2645 and LIMS-PS-2647) andA. pacificum (LMBE-C4), characterised their domain structures, and resolved evolutionary events. The sxtA gene was encoded on the genome without introns, and was identical in length (4002 bp) between two A. catenella strains, but their sequences differed from A. pacificum (5031 bp). SxtA consists of four domains, sxtA1, sxtA2, sxtA3, and sxtA4; however, A. pacificum has an extra domain TauD near sxtA1. Each domain had >64.4% GC content, with the highest being 71.6% in sxtA3. Molecular divergence was found to be significantly higher in sxtA4 than in the other domains. Phylogenetic trees of sxtA and separate domains showed that bacteria diverged earliest, followed by non-toxic, toxic cyanobacteria, toxic dinoflagellates. While sxtA domains in Alexandrium were similar to the PKS-like structure with the conserved sxtA1, sxtA2, and sxtA3. PKS_KS may be replaced by sxtA4 in toxic Alexandrium. These suggest that sxtA in Alexandrium may have evolved by acquiring specific domains, whose modification and complexity markedly affect toxin biosynthesis.
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Affiliation(s)
- Quynh Thi Nhu Bui
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - Hansol Kim
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - Hui Wang
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea; Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, University of South China, Hengyang 421001, China
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea.
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8
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Long M, Krock B, Castrec J, Tillmann U. Unknown Extracellular and Bioactive Metabolites of the Genus Alexandrium: A Review of Overlooked Toxins. Toxins (Basel) 2021; 13:905. [PMID: 34941742 PMCID: PMC8703713 DOI: 10.3390/toxins13120905] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/08/2021] [Accepted: 12/14/2021] [Indexed: 12/04/2022] Open
Abstract
Various species of Alexandrium can produce a number of bioactive compounds, e.g., paralytic shellfish toxins (PSTs), spirolides, gymnodimines, goniodomins, and also uncharacterised bioactive extracellular compounds (BECs). The latter metabolites are released into the environment and affect a large range of organisms (from protists to fishes and mammalian cell lines). These compounds mediate allelochemical interactions, have anti-grazing and anti-parasitic activities, and have a potentially strong structuring role for the dynamic of Alexandrium blooms. In many studies evaluating the effects of Alexandrium on marine organisms, only the classical toxins were reported and the involvement of BECs was not considered. A lack of information on the presence/absence of BECs in experimental strains is likely the cause of contrasting results in the literature that render impossible a distinction between PSTs and BECs effects. We review the knowledge on Alexandrium BEC, (i.e., producing species, target cells, physiological effects, detection methods and molecular candidates). Overall, we highlight the need to identify the nature of Alexandrium BECs and urge further research on the chemical interactions according to their ecological importance in the planktonic chemical warfare and due to their potential collateral damage to a wide range of organisms.
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Affiliation(s)
- Marc Long
- IFREMER, Centre de Brest, DYNECO Pelagos, 29280 Plouzané, France;
| | - Bernd Krock
- Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany;
| | - Justine Castrec
- University Brest, CNRS, IRD, Ifremer, LEMAR, 29280 Plouzané, France;
- Station de Recherches Sous-Marines et Océanographiques (STARESO), Punta Revellata, BP33, 20260 Calvi, France
| | - Urban Tillmann
- Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany;
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9
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Pearson LA, D'Agostino PM, Neilan BA. Recent developments in quantitative PCR for monitoring harmful marine microalgae. HARMFUL ALGAE 2021; 108:102096. [PMID: 34588118 DOI: 10.1016/j.hal.2021.102096] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Marine microalgae produce a variety of specialised metabolites that have toxic effects on humans, farmed fish, and marine wildlife. Alarmingly, many of these compounds bioaccumulate in the tissues of shellfish and higher trophic organisms, including species consumed by humans. Molecular methods are emerging as a potential alternative and complement to the conventional microscopic diagnosis of toxic or otherwise harmful microalgal species. Quantitative PCR (qPCR) in particular, has gained popularity over the past decade as a sensitive, rapid, and cost-effective method for monitoring harmful microalgae. Assays targeting taxonomic marker genes provide the opportunity to identify and quantify (or semi-quantify) microalgal species and importantly to pre-empt bloom events. Moreover, the discovery of paralytic shellfish toxin biosynthesis genes in dinoflagellates has enabled researchers to directly monitor toxigenic species in coastal waters and fisheries. This review summarises the recent developments in qPCR detection methods for harmful microalgae, with emphasis on emerging toxin gene monitoring technologies.
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Affiliation(s)
- Leanne A Pearson
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Paul M D'Agostino
- Chair of Technical Biochemistry, Technical University of Dresden, Dresden, Germany
| | - Brett A Neilan
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia.
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10
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Mendoza-Flores A, Leyva-Valencia I, Hernández-Sandoval FE, Galindo-Sánchez CE, Band-Schmidt CJ, Bustillos-Guzmán JJ. Relationship between paralytic shellfish toxin content and sxtA gene copy number in different growth phases of Gymnodinium catenatum (Dinophyceae). Toxicon 2021; 199:68-71. [PMID: 34087288 DOI: 10.1016/j.toxicon.2021.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/28/2021] [Accepted: 05/29/2021] [Indexed: 11/29/2022]
Abstract
Paralytic shellfish toxin (PST) content in the dinoflagellate Gymnodinium catenatum changes with culture age, with a higher toxin concentration in the logarithmic phase that decreases when the culture ages. The gene copy number (GCN) of domains sxtA1 and sxtA4 was higher in the lag and stationary phase, and lag phase, respectively. No relationship was found between the GCN of the domains sxtA4 and sxtA1 with the PST content in G. catenatum.
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Affiliation(s)
- Armando Mendoza-Flores
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. Instituto Politécnico Nacional, Playa Palo de Sta. Rita, La Paz, Baja California Sur, Mexico.
| | - Ignacio Leyva-Valencia
- CONACyT-Instituto Politécnico Nacional - Centro Interdisciplinario de Ciencias Marinas, Av. Instituto Politécnico Nacional, Playa Palo de Sta. Rita, La Paz, Baja California Sur, Mexico
| | - Francisco E Hernández-Sandoval
- Centro de Investigaciones Biológicas del Noroeste. Av. Instituto Politécnico Nacional, 195 Playa Palo de Sta. Rita, La Paz, Baja California Sur, Mexico
| | - Clara E Galindo-Sánchez
- Centro de Investigación Científica y de Educación Superior de Ensenada. Carretera Ensenada - Tijuana, 3918, Zona Playitas, Ensenada, Baja California, Mexico
| | - Christine J Band-Schmidt
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. Instituto Politécnico Nacional, Playa Palo de Sta. Rita, La Paz, Baja California Sur, Mexico
| | - José J Bustillos-Guzmán
- Centro de Investigaciones Biológicas del Noroeste. Av. Instituto Politécnico Nacional, 195 Playa Palo de Sta. Rita, La Paz, Baja California Sur, Mexico
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11
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Yarimizu K, Sildever S, Hamamoto Y, Tazawa S, Oikawa H, Yamaguchi H, Basti L, Mardones JI, Paredes-Mella J, Nagai S. Development of an absolute quantification method for ribosomal RNA gene copy numbers per eukaryotic single cell by digital PCR. HARMFUL ALGAE 2021; 103:102008. [PMID: 33980448 DOI: 10.1016/j.hal.2021.102008] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/04/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
Recent increase of Harmful Algal Blooms (HAB) causes world-wide ecological, economical, and health issues, and more attention is paid to frequent coastal monitoring for the early detection of HAB species to prevent or reduce such impacts. Use of molecular tools in addition to traditional microscopy-based observation has become one of the promising methodologies for coastal monitoring. However, as ribosomal RNA (rRNA) genes are commonly targeted in molecular studies, variability in the rRNA gene copy number within and between species must be considered to provide quantitative information in quantitative PCR (qPCR), digital PCR (dPCR), and metabarcoding analyses. Currently, this information is only available for a limited number of species. The present study utilized a dPCR technology to quantify copy numbers of rRNA genes per single cell in 16 phytoplankton species, the majority of which are toxin-producers, using a newly developed universal primer set accompanied by a labeled probe with a fluorophore and a double-quencher. In silico PCR using the newly developed primers allowed the detection of taxa from 8 supergroups, demonstrating universality and broad coverage of the primer set. Chelex buffer was found to be suitable for DNA extraction to obtain DNA fragments with suitable size to avoid underestimation of the copy numbers. The study successfully demonstrated the first comparison of absolute quantification of 18S rRNA copy numbers per cell from 16 phytoplankton species by the dPCR technology.
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Affiliation(s)
- Kyoko Yarimizu
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan; Office of Industry-Academia-Government and Community Collaboration, Hiroshima University, 1-3-2 22 Kagamiyama, Higashi-Hiroshima City, Hiroshima 739-8511, Japan
| | - Sirje Sildever
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan; Department of Marine Systems, Tallinn University of Technology, Akadeemia tee 15A, 12618 Tallinn, Estonia
| | - Yoko Hamamoto
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
| | - Satoshi Tazawa
- AXIOHELIX Co. Ltd, 12-17 Kandaizumicho, Chiyoda-ku, Tokyo 101-0024, Japan
| | - Hiroshi Oikawa
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
| | - Haruo Yamaguchi
- Faculty of Agriculture and Marine Sciences, Kochi University, Nankoku, Kochi 783-8502, Japan
| | - Leila Basti
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, Japan
| | - Jorge I Mardones
- Instituto de Fomento Pesquero, Centro de Estudios de Algas Nocivas (IFOP-CREAN), Padre Harter 574, Puerto Montt 5501679, Chile; Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile
| | - Javier Paredes-Mella
- Instituto de Fomento Pesquero, Centro de Estudios de Algas Nocivas (IFOP-CREAN), Padre Harter 574, Puerto Montt 5501679, Chile
| | - Satoshi Nagai
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan.
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12
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Geffroy S, Lechat MM, Le Gac M, Rovillon GA, Marie D, Bigeard E, Malo F, Amzil Z, Guillou L, Caruana AMN. From the sxtA4 Gene to Saxitoxin Production: What Controls the Variability Among Alexandrium minutum and Alexandrium pacificum Strains? Front Microbiol 2021; 12:613199. [PMID: 33717003 PMCID: PMC7944994 DOI: 10.3389/fmicb.2021.613199] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 02/03/2021] [Indexed: 12/22/2022] Open
Abstract
Paralytic shellfish poisoning (PSP) is a human foodborne syndrome caused by the consumption of shellfish that accumulate paralytic shellfish toxins (PSTs, saxitoxin group). In PST-producing dinoflagellates such as Alexandrium spp., toxin synthesis is encoded in the nuclear genome via a gene cluster (sxt). Toxin production is supposedly associated with the presence of a 4th domain in the sxtA gene (sxtA4), one of the core genes of the PST gene cluster. It is postulated that gene expression in dinoflagellates is partially constitutive, with both transcriptional and post-transcriptional processes potentially co-occurring. Therefore, gene structure and expression mode are two important features to explore in order to fully understand toxin production processes in dinoflagellates. In this study, we determined the intracellular toxin contents of twenty European Alexandrium minutum and Alexandrium pacificum strains that we compared with their genome size and sxtA4 gene copy numbers. We observed a significant correlation between the sxtA4 gene copy number and toxin content, as well as a moderate positive correlation between the sxtA4 gene copy number and genome size. The 18 toxic strains had several sxtA4 gene copies (9-187), whereas only one copy was found in the two observed non-toxin producing strains. Exploration of allelic frequencies and expression of sxtA4 mRNA in 11 A. minutum strains showed both a differential expression and specific allelic forms in the non-toxic strains compared with the toxic ones. Also, the toxic strains exhibited a polymorphic sxtA4 mRNA sequence between strains and between gene copies within strains. Finally, our study supported the hypothesis of a genetic determinism of toxin synthesis (i.e., the existence of several genetic isoforms of the sxtA4 gene and their copy numbers), and was also consistent with the hypothesis that constitutive gene expression and moderation by transcriptional and post-transcriptional regulation mechanisms are the cause of the observed variability in the production of toxins by A. minutum.
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Affiliation(s)
| | | | | | | | - Dominique Marie
- Sorbonne Université, CNRS, UMR 7144 Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
| | - Estelle Bigeard
- Sorbonne Université, CNRS, UMR 7144 Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
| | | | | | - Laure Guillou
- Sorbonne Université, CNRS, UMR 7144 Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
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13
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Cho Y, Hidema S, Omura T, Koike K, Koike K, Oikawa H, Konoki K, Oshima Y, Yotsu-Yamashita M. SxtA localizes to chloroplasts and changes to its 3'UTR may reduce toxin biosynthesis in non-toxic Alexandrium catenella (Group I) ✰. HARMFUL ALGAE 2021; 101:101972. [PMID: 33526188 DOI: 10.1016/j.hal.2020.101972] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/14/2020] [Accepted: 12/19/2020] [Indexed: 06/12/2023]
Abstract
SxtA is the enzyme that catalyses the first step of saxitoxin biosynthesis. We developed an immunofluorescent method to detect SxtA using antibodies against SxtA peptides. Confocal microscopy revealed the presence of abundant, sub-cellularly localized signal in cells of toxic species and its absence in non-toxic species. Co-localization of SxtA with Rubisco II and ultra-structural observation by transmission electron microscopy strongly suggested the association of SxtA with chloroplasts. We also characterized a non-toxic sub-clone of Alexandrium catenella (Group I) to elucidate the mutation responsible for its loss of toxicity. Although sxtA4 gene copy number was indistinguishable in toxic and non-toxic sub-clones, mRNA and protein expression were significantly reduced in the non-toxic sub-clone and we uncovered sequence variation at the 3' untranslated region (3'UTR) of sxtA4 mRNA. We propose that differences in the sxtA4 mRNA 3'UTR lead to down-regulation of STX biosynthesis post-transcriptionally, thereby explaining the differences in toxicity amongst different A. catenella (Group I) sub-clones.
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Affiliation(s)
- Yuko Cho
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan.
| | - Shizu Hidema
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University, 1 Hikariga-oka, Fukushima 960-1295, Japan
| | - Takuo Omura
- Laboratory of Aquatic Science Consultant Co., Ltd. 2-30-17, Higashikamata, Ota-ku, Tokyo 144-0031, Japan
| | - Kazuhiko Koike
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Kanae Koike
- Natural Science Center for Basic Research and Development, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Hiroshi Oikawa
- Japan Fisheries Research and Education Agency, Fisheries Technology Institute, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa 236-8648, Japan
| | - Keiichi Konoki
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Yasukatsu Oshima
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
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14
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Akbar MA, Mohd Yusof NY, Tahir NI, Ahmad A, Usup G, Sahrani FK, Bunawan H. Biosynthesis of Saxitoxin in Marine Dinoflagellates: An Omics Perspective. Mar Drugs 2020; 18:md18020103. [PMID: 32033403 PMCID: PMC7073992 DOI: 10.3390/md18020103] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/09/2020] [Accepted: 01/09/2020] [Indexed: 02/07/2023] Open
Abstract
Saxitoxin is an alkaloid neurotoxin originally isolated from the clam Saxidomus giganteus in 1957. This group of neurotoxins is produced by several species of freshwater cyanobacteria and marine dinoflagellates. The saxitoxin biosynthesis pathway was described for the first time in the 1980s and, since then, it was studied in more than seven cyanobacterial genera, comprising 26 genes that form a cluster ranging from 25.7 kb to 35 kb in sequence length. Due to the complexity of the genomic landscape, saxitoxin biosynthesis in dinoflagellates remains unknown. In order to reveal and understand the dynamics of the activity in such impressive unicellular organisms with a complex genome, a strategy that can carefully engage them in a systems view is necessary. Advances in omics technology (the collective tools of biological sciences) facilitated high-throughput studies of the genome, transcriptome, proteome, and metabolome of dinoflagellates. The omics approach was utilized to address saxitoxin-producing dinoflagellates in response to environmental stresses to improve understanding of dinoflagellates gene–environment interactions. Therefore, in this review, the progress in understanding dinoflagellate saxitoxin biosynthesis using an omics approach is emphasized. Further potential applications of metabolomics and genomics to unravel novel insights into saxitoxin biosynthesis in dinoflagellates are also reviewed.
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Affiliation(s)
- Muhamad Afiq Akbar
- School of Bioscience and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia;
| | - Nurul Yuziana Mohd Yusof
- Department of Earth Science and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia; (N.Y.M.Y.); (F.K.S.)
| | - Noor Idayu Tahir
- Malaysian Palm Oil Board, No 6, Persiaran Institusi, Bandar Baru Bangi, Kajang 43000, Selangor, Malaysia;
| | - Asmat Ahmad
- University College Sabah Foundation, Jalan Sanzac, Kota Kinabalu 88100, Sabah, Malaysia; (A.A.); (G.U.)
| | - Gires Usup
- University College Sabah Foundation, Jalan Sanzac, Kota Kinabalu 88100, Sabah, Malaysia; (A.A.); (G.U.)
| | - Fathul Karim Sahrani
- Department of Earth Science and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia; (N.Y.M.Y.); (F.K.S.)
| | - Hamidun Bunawan
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia
- Correspondence: ; Tel.: +60-389-214-546
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15
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Lee HG, Kim HM, Min J, Park C, Jeong HJ, Lee K, Kim KY. Quantification of the paralytic shellfish poisoning dinoflagellate Alexandrium species using a digital PCR. HARMFUL ALGAE 2020; 92:101726. [PMID: 32113599 DOI: 10.1016/j.hal.2019.101726] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 12/01/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
A ubiquitous dinoflagellate, Alexandrium, produces paralytic shellfish toxin (PST), and its outbreaks have negative impacts on aquaculture, fisheries, human health, and the marine ecosystem. To minimize such damages, a routine monitoring program of toxic species must be implemented with a suitable analytical technique for their identification and quantification. However, the taxonomic identification and cell quantification of Alexandrium species based on their external morphology under a light microscope, or by using conventional molecular approaches have limited sensitivity and reproducibility. To address these challenges, we have developed an advanced protocol using droplet-digital PCR (ddPCR) for the discrimination and enumeration of three co-occurring Alexandrium species (A. affine, A. catenella, and A. pacificum) in environmental samples. Copies of species-specific internal transcribed spacer (ITS) per cell, which were calculated from environmental samples spiked with various numbers of culture cells, were used to estimate the abundance of species in the field samples. There were no significant differences in ITS copies estimated by the digital PCR assay between environmental samples from different localities, spiked artificially with a consistent number of cells from Alexandrium cultures. This sensitive assay was applied to determine the abundance and vertical distribution of those populations in the southern coastal waters of Korea. In spring, A. catenella was the dominant species, followed by the non-toxic A. affine in summers. A novel digital PCR assay can also be used to monitor other harmful marine protists that require high sample throughput and low detection limit with high accuracy and precision.
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Affiliation(s)
- Hyun-Gwan Lee
- Department of Oceanography, College of Natural Sciences, Chonnam National University, Gwangju 61186, Republic of Korea; Marine Ecosystem Disturbing and Harmful Organisms (MEDHO) Research Center, Gwangju 61186, Republic of Korea
| | - Hye Mi Kim
- Department of Oceanography, College of Natural Sciences, Chonnam National University, Gwangju 61186, Republic of Korea; Marine Ecosystem Disturbing and Harmful Organisms (MEDHO) Research Center, Gwangju 61186, Republic of Korea
| | - Juhee Min
- Department of Oceanography, College of Natural Sciences, Chonnam National University, Gwangju 61186, Republic of Korea; Marine Ecosystem Disturbing and Harmful Organisms (MEDHO) Research Center, Gwangju 61186, Republic of Korea
| | - Chungoo Park
- Marine Ecosystem Disturbing and Harmful Organisms (MEDHO) Research Center, Gwangju 61186, Republic of Korea; School of Biological Sciences and Technology, College of Natural Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Hae Jin Jeong
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Kitack Lee
- School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Kwang Young Kim
- Department of Oceanography, College of Natural Sciences, Chonnam National University, Gwangju 61186, Republic of Korea; Marine Ecosystem Disturbing and Harmful Organisms (MEDHO) Research Center, Gwangju 61186, Republic of Korea.
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16
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Murray SA, Ruvindy R, Kohli GS, Anderson DM, Brosnahan ML. Evaluation of sxtA and rDNA qPCR assays through monitoring of an inshore bloom of Alexandrium catenella Group 1. Sci Rep 2019; 9:14532. [PMID: 31601884 PMCID: PMC6787220 DOI: 10.1038/s41598-019-51074-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 09/24/2019] [Indexed: 12/16/2022] Open
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 106 cells L-1. In this study, we compared sxtA assay performance to a qPCR assay targeted to a species-specific region of ribosomal DNA (rDNA) and an established fluorescent in situ hybridization (FISH) microscopy method. Passing-Bablok regression analyses revealed the sxtA assay to overestimate abundances when <5 cell equivalents A. catenella DNA were analysed, but otherwise was closer to microscopy estimates than the rDNA assay, which overestimated abundance across the full range of concentrations analysed, indicative of a copy number difference between the bloom population and a culture used for assay calibration a priori. In contrast, the sxtA assay performed more consistently, indicating less copy number variation. The sxtA assay was generally reliable, fast and effective in quantifying A. catenella and was predictive of PST contamination of shellfish.
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Affiliation(s)
- Shauna A Murray
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia.
| | - Rendy Ruvindy
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia
| | - Gurjeet S Kohli
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia
- Ramaciotti Centre for Gene Function Analysis, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Donald M Anderson
- Woods Hole Oceanographic Institution, MS # 32, 266 Woods Hole Road, Woods Hole, Massachusetts, 02543, United States
| | - Michael L Brosnahan
- Woods Hole Oceanographic Institution, MS # 32, 266 Woods Hole Road, Woods Hole, Massachusetts, 02543, United States
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17
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Verma A, Barua A, Ruvindy R, Savela H, Ajani PA, Murray SA. The Genetic Basis of Toxin Biosynthesis in Dinoflagellates. Microorganisms 2019; 7:E222. [PMID: 31362398 PMCID: PMC6722697 DOI: 10.3390/microorganisms7080222] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 07/23/2019] [Accepted: 07/27/2019] [Indexed: 02/07/2023] Open
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.
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Affiliation(s)
- Arjun Verma
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia.
| | - Abanti Barua
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
- Department of Microbiology, Noakhali Science and Technology University, Chittagong 3814, Bangladesh
| | - Rendy Ruvindy
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
| | - Henna Savela
- Finnish Environment Institute, Marine Research Centre, 00790 Helsinki, Finland
| | - Penelope A Ajani
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
| | - Shauna A Murray
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
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18
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Kremp A, Hansen PJ, Tillmann U, Savela H, Suikkanen S, Voß D, Barrera F, Jakobsen HH, Krock B. Distributions of three Alexandrium species and their toxins across a salinity gradient suggest an increasing impact of GDA producing A. pseudogonyaulax in shallow brackish waters of Northern Europe. HARMFUL ALGAE 2019; 87:101622. [PMID: 31349884 DOI: 10.1016/j.hal.2019.101622] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 05/28/2019] [Accepted: 05/29/2019] [Indexed: 06/10/2023]
Abstract
Blooms of Alexandrium spp. are a well-known phenomenon in Northern European waters. While A. tamarense/catenella, and A. pseudogonyaulax have been reported from marine waters, high densities of A. ostenfeldii are mainly observed at lower salinities in North Sea estuaries and the Baltic Sea, suggesting salinity as a driver of Alexandrium species composition and toxin distribution. To investigate this relationship, an oceanographic expedition through a natural salinity gradient was conducted in June 2016 along the coasts of Denmark. Besides hydrographic data, phytoplankton and sediment samples were collected for analyses of Alexandrium spp. cell and cyst abundances, for toxin measurement and cell isolation. Plankton data revealed the predominance of A. pseudogonyaulax at all transect stations while A. ostenfeldii and A. catenella generally contributed a minor fraction to the Alexandrium community. High abundances of A. pseudogonyaulax in the shallow enclosed Limfjord were accompanied by high amounts of goniodomin A (GDA). This toxin was also detected at low abundances along with A. pseudogonyaulax in the North Sea and the Kattegat. Genetic and morphological characterization of established strains showed high similarity of the Northern European population to distant geographic populations. Despite low cell abundances of A. ostenfeldii, different profiles of cycloimines were measured in the North Sea and in the Limfjord. This field survey revealed that salinity alone does not determine Alexandrium species and toxin distribution, but emphasizes the importance of habitat conditions such as proximity to seed banks, shelter, and high nutrient concentrations. The results show that A. pseudogonyaulax has become a prominent member of the Alexandrium spp. community over the past decade in the study area. Analyses of long term monitoring data from the Limfjord confirmed a recent shift to A. pseudogonyaulax dominance. Cyst and toxin records of the species in Kiel Bight suggest a spreading potential into the brackish Baltic Sea, which might lead to an expansion of blooms under future climate conditions.
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Affiliation(s)
- Anke Kremp
- Leibniz Institut für Ostseeforschung Warnemünde, Seestr. 15, 18119 Rostock, Germany; Finnish Environment Institute, Marine Research Centre, Agnes Sjöbergin katu 2, 00790 Helsinki, Finland.
| | - Per Juel Hansen
- University of Copenhagen, Marine Biological Section, Strandpromenaden 5, 3000 Helsingør, Denmark
| | - Urban Tillmann
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, D-27570 Bremerhaven, Germany
| | - Henna Savela
- Finnish Environment Institute, Marine Research Centre, Agnes Sjöbergin katu 2, 00790 Helsinki, Finland; Department of Biochemistry/Biotechnology, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland
| | - Sanna Suikkanen
- Finnish Environment Institute, Marine Research Centre, Agnes Sjöbergin katu 2, 00790 Helsinki, Finland
| | - Daniela Voß
- Institut für Chemie und Biologie des Meeres (ICBM), Schleusenstr. 1, 26382 Wilhelmshaven, Germany
| | - Facundo Barrera
- Departamento de Química Ambiental, Facultad de Ciencias. Centro de Investigación en Biodiversidad y Ambientes Sustentables. Universidad Católica de la Santísima Concepción. Alonso de Ribera 2850, 4090541, Concepción, Chile
| | - Hans Henrik Jakobsen
- University of Århus, Institute for Bioscience, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Bernd Krock
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, D-27570 Bremerhaven, Germany
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19
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Ruvindy R, Bolch CJ, MacKenzie L, Smith KF, Murray SA. qPCR Assays for the Detection and Quantification of Multiple Paralytic Shellfish Toxin-Producing Species of Alexandrium. Front Microbiol 2018; 9:3153. [PMID: 30619217 PMCID: PMC6305576 DOI: 10.3389/fmicb.2018.03153] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 12/05/2018] [Indexed: 11/30/2022] Open
Abstract
Paralytic shellfish toxin producing dinoflagellates have negatively impacted the shellfish aquaculture industry worldwide, including in Australia and New Zealand. Morphologically identical cryptic species of dinoflagellates that may differ in toxicity, in particular, species of the former Alexandrium tamarense species complex, co-occur in Australia, as they do in multiple regions in Asia and Europe. To understand the dynamics and the ecological drivers of the growth of each species in the field, accurate quantification at the species level is crucial. We have developed the first quantitative polymerase chain reaction (qPCR) primers for A. australiense, and new primers targeting A. ostenfeldii, A. catenella, and A. pacificum. We showed that our new primers for A. pacificum are more specific than previously published primer pairs. These assays can be used to quantify planktonic cells and cysts in the water column and in sediment samples with limits of detection of 2 cells/L for the A. catenella and A. australiense assays, 2 cells/L and 1 cyst/mg sediment for the A. pacificum assay, and 1 cells/L for the A. ostenfeldii assay, and efficiencies of >90%. We utilized these assays to discriminate and quantify co-occurring A. catenella, A. pacificum, and A. australiense in samples from the east coast of Tasmania, Australia.
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Affiliation(s)
- Rendy Ruvindy
- Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
| | - Christopher J. Bolch
- Institute for Marine and Antarctic Studies, University of Tasmania, Launceston, TAS, Australia
| | | | | | - Shauna A. Murray
- Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
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20
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Grzebyk D, Audic S, Lasserre B, Abadie E, de Vargas C, Bec B. Insights into the harmful algal flora in northwestern Mediterranean coastal lagoons revealed by pyrosequencing metabarcodes of the 28S rRNA gene. HARMFUL ALGAE 2017; 68:1-16. [PMID: 28962972 DOI: 10.1016/j.hal.2017.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 06/02/2017] [Accepted: 06/11/2017] [Indexed: 06/07/2023]
Abstract
This study investigated the genetic diversity of phytoplankton communities in six shallow lagoons located on the French coast of the northwestern Mediterranean Sea that represented a trophic gradient ranging from oligotrophic to hypereutrophic. The phytoplankton communities were sampled once a month from spring (May) to the beginning of autumn (September/early October) in 2012 and fractionated by size. Metabarcodes were generated from cDNAs by targeting the D1-D2 region of the 28S rRNA gene and pyrosequenced using Roche 454 technology. Examination of the annotated barcodes revealed harmful algal species not previously documented in these lagoons. Three ichthyotoxic species belonging to Pfiesteriaceae were detected: Luciella masanensis was relatively widespread and abundant in many samples, whereas Pfiesteria piscicida and Stoeckeria changwonensis were found as single barcode sequences. Furthermore, a phylogenetic analysis of barcodes annotated as belonging to Pfiesteriaceae suggested the existence of two previously undescribed clades. The other toxic or potentially harmful dinoflagellates detected through rare barcodes were Dinophysis acuminata, Vulcanodinium rugosum, Alexandrium andersonii and A. ostenfeldii. The two most abundant dinoflagellate taxa were Gymnodinium litoralis and Akashiwo sanguinea with respect to sequence numbers. Four diatom species from the genus Pseudo-nitzschia that potentially produce domoic acid were identified (P. galaxiae, P. delicatissima, P. brasiliana and P. calliantha). These observations are discussed in terms of the literature and monitoring records related to the identified taxa in this Mediterranean area.
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Affiliation(s)
- Daniel Grzebyk
- UMR MARBEC, Centre for Marine Biodiversity, Exploitation and Conservation (IRD, Ifremer, Université Montpellier, CNRS), Université Montpellier, CC 093, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France.
| | - Stéphane Audic
- CNRS, UMR 7144, Adaptation et Diversité en Milieu Marin, Equipe EPEP, Station Biologique de Roscoff, 29680 Roscoff, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris 6), UMR 7144, Station Biologique de Roscoff, 29680 Roscoff, France
| | - Bernard Lasserre
- UMR MARBEC, Centre for Marine Biodiversity, Exploitation and Conservation (IRD, Ifremer, Université Montpellier, CNRS), Université Montpellier, CC 093, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Eric Abadie
- UMR MARBEC, Centre for Marine Biodiversity, Exploitation and Conservation (IRD, Ifremer, Université de Montpellier, CNRS), Laboratoire Environnement et Ressources du Languedoc-Roussillon (LER-LR), Station Ifremer, Avenue Jean Monnet, CS 30171, 34203 Sète Cedex, France
| | - Colomban de Vargas
- CNRS, UMR 7144, Adaptation et Diversité en Milieu Marin, Equipe EPEP, Station Biologique de Roscoff, 29680 Roscoff, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris 6), UMR 7144, Station Biologique de Roscoff, 29680 Roscoff, France
| | - Béatrice Bec
- UMR MARBEC, Centre for Marine Biodiversity, Exploitation and Conservation (IRD, Ifremer, Université Montpellier, CNRS), Université Montpellier, CC 093, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
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21
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Molgó J, Marchot P, Aráoz R, Benoit E, Iorga BI, Zakarian A, Taylor P, Bourne Y, Servent D. Cyclic imine toxins from dinoflagellates: a growing family of potent antagonists of the nicotinic acetylcholine receptors. J Neurochem 2017; 142 Suppl 2:41-51. [PMID: 28326551 DOI: 10.1111/jnc.13995] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/13/2017] [Accepted: 02/15/2017] [Indexed: 12/24/2022]
Abstract
We present an overview of the toxicological profile of the fast-acting, lipophilic macrocyclic imine toxins, an emerging family of organic compounds associated with algal blooms, shellfish contamination and neurotoxicity. Worldwide, shellfish contamination incidents are expanding; therefore, the significance of these toxins for the shellfish food industry deserves further study. Emphasis is directed to the dinoflagellate species involved in their production, their chemical structures, and their specific mode of interaction with their principal natural molecular targets, the nicotinic acetylcholine receptors, or with the soluble acetylcholine-binding protein, used as a surrogate receptor model. The dinoflagellates Karenia selliformis and Alexandrium ostenfeldii / A. peruvianum have been implicated in the biosynthesis of gymnodimines and spirolides, while Vulcanodinium rugosum is the producer of pinnatoxins and portimine. The cyclic imine toxins are characterized by a macrocyclic skeleton comprising 14-27 carbon atoms, flanked by two conserved moieties, the cyclic imine and the spiroketal ring system. These phycotoxins generally display high affinity and broad specificity for the muscle type and neuronal nicotinic acetylcholine receptors, a feature consistent with their binding site at the receptor subunit interfaces, composed of residues highly conserved among all nAChRs, and explaining the diverse toxicity among animal species. This is an article for the special issue XVth International Symposium on Cholinergic Mechanisms.
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Affiliation(s)
- Jordi Molgó
- Commissariat à l'Energie Atomique et aux énergies alternatives (CEA), Institut de Biologie et Technologies de Saclay (IBITECS), Université Paris-Saclay, Service d'Ingénierie Moléculaire des Protéines, Gif-sur-Yvette, France.,Institut des Neurosciences Paris-Saclay, UMR 9197, Centre National de la Recherche Scientifique (CNRS)/Université Paris-Sud, Gif-sur-Yvette Cedex, France
| | - Pascale Marchot
- Aix-Marseille Université / Centre National de la Recherche Scientifique, Architecture et Fonction des Macromolécules Biologiques laboratory, Marseille, France
| | - Rómulo Aráoz
- Commissariat à l'Energie Atomique et aux énergies alternatives (CEA), Institut de Biologie et Technologies de Saclay (IBITECS), Université Paris-Saclay, Service d'Ingénierie Moléculaire des Protéines, Gif-sur-Yvette, France.,Institut des Neurosciences Paris-Saclay, UMR 9197, Centre National de la Recherche Scientifique (CNRS)/Université Paris-Sud, Gif-sur-Yvette Cedex, France
| | - Evelyne Benoit
- Commissariat à l'Energie Atomique et aux énergies alternatives (CEA), Institut de Biologie et Technologies de Saclay (IBITECS), Université Paris-Saclay, Service d'Ingénierie Moléculaire des Protéines, Gif-sur-Yvette, France.,Institut des Neurosciences Paris-Saclay, UMR 9197, Centre National de la Recherche Scientifique (CNRS)/Université Paris-Sud, Gif-sur-Yvette Cedex, France
| | - Bogdan I Iorga
- Centre National de la Recherche Scientifique (CNRS), Institut de Chimie des Substances Naturelles, UPR 2301, Labex LERMIT, Gif-sur-Yvette, France
| | - Armen Zakarian
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California, USA
| | - Palmer Taylor
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
| | - Yves Bourne
- Aix-Marseille Université / Centre National de la Recherche Scientifique, Architecture et Fonction des Macromolécules Biologiques laboratory, Marseille, France
| | - Denis Servent
- Commissariat à l'Energie Atomique et aux énergies alternatives (CEA), Institut de Biologie et Technologies de Saclay (IBITECS), Université Paris-Saclay, Service d'Ingénierie Moléculaire des Protéines, Gif-sur-Yvette, France
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22
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Park TG, Kim JJ, Kim WJ, Won KM. Development of real-time RT-PCR for detecting viable Cochlodinium polykrikoides (Dinophyceae) cysts in sediment. HARMFUL ALGAE 2016; 60:36-44. [PMID: 28073561 DOI: 10.1016/j.hal.2016.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 09/09/2016] [Accepted: 10/22/2016] [Indexed: 06/06/2023]
Abstract
Morphological observations have confirmed that cysts are produced by dinoflagellates. However, finding a seed bed or unknown cysts in field samples by microscopy is extremely time consuming. Real-time PCR has been used to facilitate the detection of dinoflagellate cysts in sediment. However, DNA from dead vegetative cells remaining on the surface sediment may persist for a long period of time, which can cause false positive DNA detection. In this study, a non-quantitative RNA targeted probe using real-time RT-PCR was developed for detection of viable cysts in sediment. Large-subunit rRNA was used to develop a species-specific RNA targeted probe for the ichthyotoxic dinoflagellate Cochlodinium polykrikoides. The sediment samples were sieved and incubated at 30°C for 3h prior to RNA extraction to remove RNA from dead cells remaining in the sediment. Nested-PCR was conducted to maximize assay sensitivity. A field survey to determine the distribution of cysts at 155 sampling stations in the western and southern part of the Korean peninsula showed that C. polykrikoides cysts were detected at five sampling stations.
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Affiliation(s)
- Tae Gyu Park
- Southeast Sea Fisheries Research Institute, National Institute of Fisheries Science (NIFS), Tongyeong 650-943, Republic of Korea.
| | - Jin Joo Kim
- Southeast Sea Fisheries Research Institute, National Institute of Fisheries Science (NIFS), Tongyeong 650-943, Republic of Korea
| | - Won Jin Kim
- Southeast Sea Fisheries Research Institute, National Institute of Fisheries Science (NIFS), Tongyeong 650-943, Republic of Korea
| | - Kyoung Mi Won
- Southeast Sea Fisheries Research Institute, National Institute of Fisheries Science (NIFS), Tongyeong 650-943, Republic of Korea
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