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Pernice MC, Closa D, Garcés E. Cryo-electron microscopy of extracellular vesicles associated with the marine toxic dinoflagellate Alexandrium minutum. HARMFUL ALGAE 2023; 123:102389. [PMID: 36894210 DOI: 10.1016/j.hal.2023.102389] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/23/2023] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
Extracellular Vesicles (EVs) are likely an important strategy of transport and communication in marine microbial community. Their isolation and characterization from axenic culture of microbial eukaryotes represents a technological challenge not fully solved. Here, for the first time, we isolated EVs from a near-axenic culture of the toxic dinoflagellate Alexandrium minutum. Pictures of the isolated vesicles were done with Cryo TEM (Cryogenic Transmission Electron Microscopy). Based on their morphotype the EVs were clustered in five major groups (rounded, rounded electron-dense, lumen electron-dense, double and irregular) and each EV was measured resulting in an average size of 0.36 µm of diameter. Taking in account that in prokaryotes it has been demonstrated that EVs play an important role in the mechanism of toxicity, this descriptive work aims to be the first step to study the possible role of EVs in the toxicity of dinoflagellates.
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Affiliation(s)
- Massimo C Pernice
- Institut de Ciències del Mar - CSIC, Passeig Marítim de la Barceloneta, 37-49, 08003 Barcelona, Spain.
| | - Daniel Closa
- Instituto de Investigaciones Biomédicas de Barcelona (IIBB), Carrer del Rosselló, 161, 08036 Barcelona, Spain
| | - Esther Garcés
- Institut de Ciències del Mar - CSIC, Passeig Marítim de la Barceloneta, 37-49, 08003 Barcelona, Spain
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Effects of Harmful Algal Blooms on Fish and Shellfish Species: A Case Study of New Zealand in a Changing Environment. Toxins (Basel) 2022; 14:toxins14050341. [PMID: 35622588 PMCID: PMC9147682 DOI: 10.3390/toxins14050341] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/11/2022] [Accepted: 05/12/2022] [Indexed: 12/03/2022] Open
Abstract
Harmful algal blooms (HABs) have wide-ranging environmental impacts, including on aquatic species of social and commercial importance. In New Zealand (NZ), strategic growth of the aquaculture industry could be adversely affected by the occurrence of HABs. This review examines HAB species which are known to bloom both globally and in NZ and their effects on commercially important shellfish and fish species. Blooms of Karenia spp. have frequently been associated with mortalities of both fish and shellfish in NZ and the sub-lethal effects of other genera, notably Alexandrium spp., on shellfish (which includes paralysis, a lack of byssus production, and reduced growth) are also of concern. Climate change and anthropogenic impacts may alter HAB population structure and dynamics, as well as the physiological responses of fish and shellfish, potentially further compromising aquatic species. Those HAB species which have been detected in NZ and have the potential to bloom and harm marine life in the future are also discussed. The use of environmental DNA (eDNA) and relevant bioassays are practical tools which enable early detection of novel, problem HAB species and rapid toxin/HAB screening, and new data from HAB monitoring of aquaculture production sites using eDNA are presented. As aquaculture grows to supply a sizable proportion of the world’s protein, the effects of HABs in reducing productivity is of increasing significance. Research into the multiple stressor effects of climate change and HABs on cultured species and using local, recent, HAB strains is needed to accurately assess effects and inform stock management strategies.
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Unsuspected intraspecific variability in the toxin production, growth and morphology of the dinoflagellate Alexandrium pacificum R.W. Litaker (Group IV) blooming in a South Western Mediterranean marine ecosystem, Annaba Bay (Algeria). Toxicon 2020; 180:79-88. [PMID: 32289356 DOI: 10.1016/j.toxicon.2020.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 04/04/2020] [Accepted: 04/07/2020] [Indexed: 11/23/2022]
Abstract
Physiological plasticity gives HABs species the ability to respond to variations in the surrounding environment. The aim of this study was to examine morphological and physiological variability in Alexandrium pacificum R.W. Litaker (Group IV) (former Alexandrium catenella) blooming in Annaba bay, Algeria. Monoclonal cultures of up to 30 strains of this neurotoxic dinoflagellate were established by the germination of single resting cysts from the surface sediment of this southern Mediterranean marine ecosystem. Ribotyping confirmed formally for the first time that A. pacificum is developing in Eastern Algerian waters. Toxin analyses of A. pacificum strains revealed substantial intraspecific variability in both the profile and toxin amount. However, the toxin profile of most strains is characterized by the dominance of GTX6 (up to 96 mol %) which is the less toxic paralytic molecule. The toxin concentrations in the isolated strains varied widely between 3.8 and 30.82 fmol cell-1. We observed an important variation in the growth rate of the studied A. pacificum strains with values ranging from 0.05 to 0.33 d-1. The lag time of the studied strains varied widely and ranged from 4 to 20 days. The intraspecific diversity could be a response to the selection pressure which may be exerted by different environmental conditions over time and which can be genetically and in turn physiologically expressed. This study highlights, for the first time, that the sediment of a limited area holds an important diversity of A. pacificum cysts which give when germinate populations with noticeable physiological plasticity. Consequently, this diversified natural populations allow an exceptional adaptation to specific environmental conditions to outcompete local microalgae and to establish HABs which could explain why this dinoflagellate is successful and expanding worldwide.
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Yi X, Zhang K, Liu R, Giesy JP, Li Z, Li W, Zhan J, Liu L, Gong Y. Transcriptomic responses of Artemia salina exposed to an environmentally relevant dose of Alexandrium minutum cells or Gonyautoxin2/3. CHEMOSPHERE 2020; 238:124661. [PMID: 31472350 DOI: 10.1016/j.chemosphere.2019.124661] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 08/10/2019] [Accepted: 08/23/2019] [Indexed: 06/10/2023]
Abstract
Toxicities of the marine algae Alexandrium minutum and its excreted gonyautoxins (GTXs) to the marine crustacean Artemia salina were investigated. Mortality was observed for neither larvae nor adult A. salina exposed to A. minutum at a density of 5000 cells/mL or 0.5 μM GTX2/3. After exposure, the full transcriptome of adult A. salina was assembled and functionally annotated. A total of 599,286 transcripts were obtained, which were clustered into 515,196 unigenes. Results of the transcriptional effect level index revealed that direct exposure to the toxic algae A. minutum caused greater alterations in the transcriptome than did exposure to the extracellular product GTX2/3. Mechanisms of effects were different between exposure of A. salina to A. minutum cells or GTX2/3. Exposure to A. minutum modulated formation of the ribonucleoprotein complex and metabolism of amino acids and lipids in A. salina. Exposure to GTX2/3 exposure inhibited expression of genes related to metabolism of chitin, which might result in disruption of molting process or disturbed sheath morphogenesis. Overall, effects on transcription observed in this study represent the first report based on application of next generation sequencing techniques to investigate the transcriptomic response of A. salina exposed to an environmentally realistic level of A. minutum or GTX2/3.
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Affiliation(s)
- Xianliang Yi
- School of Food and Environment, Dalian University of Technology, Panjin Campus, Panjin City, Liaoning, China
| | - Keke Zhang
- School of Food and Environment, Dalian University of Technology, Panjin Campus, Panjin City, Liaoning, China
| | - Renyan Liu
- National Marine Environmental Monitoring Center, Dalian City, Liaoning, China.
| | - John P Giesy
- Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon SK, S7N 5B4, Saskatchewan, Canada; Toxicology Centre, University of Saskatchewan, Saskatoon SK, S7N 5B4, Saskatchewan, Canada; Department of Environmental Science, Baylor University, Waco, TX, United States
| | - Zhaochuan Li
- School of Food and Environment, Dalian University of Technology, Panjin Campus, Panjin City, Liaoning, China
| | - Wentao Li
- School of Food and Environment, Dalian University of Technology, Panjin Campus, Panjin City, Liaoning, China
| | - Jingjing Zhan
- School of Food and Environment, Dalian University of Technology, Panjin Campus, Panjin City, Liaoning, China
| | - Lifen Liu
- School of Food and Environment, Dalian University of Technology, Panjin Campus, Panjin City, Liaoning, China
| | - Yufeng Gong
- School of Food and Environment, Dalian University of Technology, Panjin Campus, Panjin City, Liaoning, China; Toxicology Centre, University of Saskatchewan, Saskatoon SK, S7N 5B4, Saskatchewan, Canada.
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Meng FQ, Song JT, Zhou J, Cai ZH. Transcriptomic Profile and Sexual Reproduction-Relevant Genes of Alexandrium minutum in Response to Nutritional Deficiency. Front Microbiol 2019; 10:2629. [PMID: 31803162 PMCID: PMC6877688 DOI: 10.3389/fmicb.2019.02629] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/29/2019] [Indexed: 11/26/2022] Open
Abstract
Alexandrium minutum is a typical marine toxic dinoflagellate responsible for producing paralytic shellfish poisoning (PSP) toxins. Until now, we know little about the genomic information of A. minutum, so a transcriptome study was conducted to clarify the physiological adaptations related to nutritional deficiency. Here, we performed RNA-Seq analysis to assess the gene expression patterns of A. minutum under N and P deficient conditions for 0 (control), 6, and 72 h. Main differences between the control and experimental groups were observed in hydrolase activity and fatty acid, lipid, protein, and P metabolism. Activities of photosystem I (PSI) and PSII were significantly down-regulated, and the endocytosis pathway (clathrin-dependent endocytosis) was significantly enriched under N and P stress compared with the control, indicating that A. minutum shifts its trophy pattern under N and P stress. We also identified several unigenes related to the process of sexual reproduction, including sex determination, sperm-egg recognition, sex differentiation, mating, and fertilization. Approximately 50% of the successfully annotated unigenes were differentially expressed between the short-term stimulated sample (6 h) and control (R). However, the expression level of most unigenes returned to normal levels after 72 h, indicating that N and P stress plays a limited role in the induction of sexual reproduction. Furthermore, the quantitative real-time PCR (qRT-PCR) results of the five representative sex-related unigenes were consistent with sequencing data, which confirmed the authenticity of transcriptomic analysis. Also, qRT-PCR analysis showed that the long and short form transcripts of the saxitoxin biosynthesis gene (sxtA) were down-regulated under the nutrient deficient condition compared with the control, indicating that N and P stress regulates sxtA expression. Overall, transcriptome analysis of A. minutum revealed that N and P deficiency induced responses associated with stress response, photosynthetic efficiency, toxin biosynthesis, and sexual reproduction. Our data indicate that algae change their trophic modes (to facultative mixotrophy) and related physiological reactions under stress conditions; this possibly represents an ecological adaption strategy in the algal life cycle.
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Affiliation(s)
- Fan-Qiang Meng
- School of Life Sciences, Tsinghua University, Beijing, China.,Shenzhen Public Platform of Screening and Application of Marine Microbial Resources, The Shenzhen International Graduate School, Tsinghua University, Shenzhen, China
| | - Jun-Ting Song
- School of Life Sciences, Tsinghua University, Beijing, China.,Shenzhen Public Platform of Screening and Application of Marine Microbial Resources, The Shenzhen International Graduate School, Tsinghua University, Shenzhen, China
| | - Jin Zhou
- Shenzhen Public Platform of Screening and Application of Marine Microbial Resources, The Shenzhen International Graduate School, Tsinghua University, Shenzhen, China
| | - Zhong-Hua Cai
- Shenzhen Public Platform of Screening and Application of Marine Microbial Resources, The Shenzhen International Graduate School, Tsinghua University, Shenzhen, China
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Transcriptional and physiological responses to inorganic nutrition in a tropical Pacific strain of Alexandrium minutum: Implications for nutrient uptakes and assimilation. Gene 2019; 711:143950. [PMID: 31255736 DOI: 10.1016/j.gene.2019.143950] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 06/25/2019] [Accepted: 06/26/2019] [Indexed: 11/22/2022]
Abstract
The marine dinoflagellate Alexandrium minutum is known to produce saxitoxins that cause paralytic shellfish poisoning in human worldwide through consumption of the contaminated shellfish mollusks. Despite numerous studies on the growth physiology and saxitoxin production of this species, the knowledge on the molecular basis of nutrient uptakes in relation to toxin production in this species is limited. In this study, relative expressions of the high-affinity transporter genes of nitrate, ammonium, and phosphate (AmNrt2, AmAmt1 and AmPiPT1) and the assimilation genes, nitrate reductase (AmNas), glutamine synthase (AmGSIII) and carbamoyl phosphate synthase (AmCPSII) from A. minutum were studied in batch clonal culture condition with two nitrogen sources (nitrate: NO3- or ammonium: NH4+) under different N:P ratios (high-P: N:P of 14 and 16, and low-P: N:P of 155). The expression of AmAmt1 was suppressed in excess NH4+-grown condition but was not observed in AmNrt2 and AmNas. Expressions of AmAmt1, AmNrt2, AmNas, AmGSIII, AmCPSII, and AmPiPT1 were high in P-deficient condition, showing that A. minutum is likely to take up nutrients for growth under P-stress condition. Conversely, relative expression of AmCPSII was incongruent with cell growth, but was well correlated with toxin quota, suggesting that the gene might involve in arginine metabolism and related toxin production pathway. The expression of AmGSIII is found coincided with higher toxin production and is believed to involve in mechanism to detoxify the cells from excess ammonium stress. The gene regulation observed in this study has provided better insights into the ecophysiology of A. minutum in relation to its adaptive strategies in unfavorable environments.
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Lewis AM, Coates LN, Turner AD, Percy L, Lewis J. A review of the global distribution of Alexandrium minutum (Dinophyceae) and comments on ecology and associated paralytic shellfish toxin profiles, with a focus on Northern Europe. JOURNAL OF PHYCOLOGY 2018; 54:581-598. [PMID: 30047623 DOI: 10.1111/jpy.12768] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/21/2018] [Indexed: 06/08/2023]
Abstract
Alexandrium minutum is a globally distributed harmful algal bloom species with many strains that are known to produce paralytic shellfish toxins (PSTs) and consequently represent a concern to human and ecosystem health. This review highlights that A. minutum typically occurs in sheltered locations, with cell growth occurring during periods of stable water conditions. Sediment characteristics are important in the persistence of this species within a location, with fine sediments providing cyst deposits for ongoing inoculation to the water column. Toxic strains of A. minutum do not produce a consistent toxin profile, different populations produce a range of PSTs in differing quantities. Novel cluster analysis of published A. minutum toxin profiles indicates five PST profile clusters globally. Some clusters are grouped geographically (Northern Europe) while others are widely spread. Isolates from Taiwan have a range of toxin profile clusters and this area appears to have the most diverse set of PST producing A. minutum populations. These toxin profiles indicate that within the United Kingdom there are two populations of A. minutum grouping with strains from Northern France and Southern Ireland. There is a degree of interconnectivity in this region due to oceanic circulation and a high level of shipping and recreational boating. Further research into the interrelationships between the A. minutum populations in this global region would be of value.
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Affiliation(s)
- Adam Michael Lewis
- Cefas, The Nothe, Barrack Road, Weymouth, Dorset, DT48UB, UK
- Faculty of Science and Technology, The University of Westminster, 115 New Cavendish Street, London, W1W6UW, UK
| | | | - Andrew D Turner
- Cefas, The Nothe, Barrack Road, Weymouth, Dorset, DT48UB, UK
| | - Linda Percy
- Faculty of Science and Technology, The University of Westminster, 115 New Cavendish Street, London, W1W6UW, UK
| | - Jane Lewis
- Faculty of Science and Technology, The University of Westminster, 115 New Cavendish Street, London, W1W6UW, UK
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Caroppo C, Roselli L, Di Leo A. Hydrological conditions and phytoplankton community in the Lesina lagoon (southern Adriatic Sea, Mediterranean). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:1784-1799. [PMID: 29101703 DOI: 10.1007/s11356-017-0599-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 10/24/2017] [Indexed: 06/07/2023]
Abstract
The Lesina lagoon (southern Adriatic Sea, Mediterranean) is a coastal lagoon located in a highly intensified farming and tourist area. A monthly sampling was carried out in 1998 in five stations, representative of different hydrological features, in order to analyse phytoplankton composition and its relation to environmental parameters. Our results showed high spatial variability of abiotic variables. Phytoplankton abundances and biomass trends showed marked seasonality, with annual peaks occurring in late winter-early spring and summer periods. Phytoplankton blooms were due to the diatom Thalassiosira pseudonana and the dinoflagellate Prorocentrum cordatum. Statistical analyses showed that salinity and nutrients were the main factors affecting phytoplankton abundance and biomass. Phytoplankton dynamics was associated both to seasonality and the hydrodynamic regime of the system. Moreover, chemical-physical data were analysed together with those collected in the same stations in 2007, to compare their dynamics under different hydrological regimes. The two periods corresponded to the closure and opening, respectively, of canals connecting the lagoon to the sea. In general, abiotic variables (salinity, dissolved oxygen, pH, nitrate, phosphate and silicate concentrations) were significantly affected by the hydrodynamic regime. These data could provide a useful basis to complement the knowledge gained through current monitoring within the framework of the European Directives, as well as to implement conservation and management strategies of these transitional waters.
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Affiliation(s)
- Carmela Caroppo
- National Research Council, Institute for Coastal Marine Environment, Via Roma 3, 74123, Taranto, Italy.
| | - Leonilde Roselli
- Department of Biological and Environmental Sciences & Technologies, University of Salento, 73100, Lecce, Italy
- Department of Lecce, Environmental Protection Agency of Puglia Region, 73100, Lecce, Italy
| | - Antonella Di Leo
- National Research Council, Institute for Coastal Marine Environment, Via Roma 3, 74123, Taranto, Italy
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Fabro E, Almandoz GO, Ferrario M, John U, Tillmann U, Toebe K, Krock B, Cembella A. Morphological, molecular, and toxin analysis of field populations of Alexandrium genus from the Argentine Sea. JOURNAL OF PHYCOLOGY 2017; 53:1206-1222. [PMID: 28793388 DOI: 10.1111/jpy.12574] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 07/22/2017] [Indexed: 06/07/2023]
Abstract
In the Argentine Sea, blooms of toxigenic dinoflagellates of the Alexandrium tamarense species complex have led to fish and bird mortalities and human deaths as a consequence of paralytic shellfish poisoning (PSP). Yet little is known about the occurrence of other toxigenic species of the genus Alexandrium, or of their toxin composition beyond coastal waters. The distribution of Alexandrium species and related toxins in the Argentine Sea was determined by sampling surface waters on an oceanographic expedition during austral spring from ~39°S to 48°S. Light microscope and SEM analysis for species identification and enumeration was supplemented by confirmatory PCR analysis from field samples. The most frequent Alexandrium taxon identified by microscopy corresponded to the classical description of A. tamarense. Only weak signals of Group I from the A. tamarense species complex were detected by PCR of bulk field samples, but phylogenetic reconstruction of rDNA sequences from single cells from one station assigned them to ribotype Group I (Alexandrium catenella). PCR probes for Alexandrium minutum and Alexandrium ostenfeldii yielded a positive signal, although A. minutum morphology did not completely match the classical description. Analysis of PSP toxin composition of plankton samples revealed toxin profiles dominated by gonyautoxins (GTX1/4). The main toxic cyclic imine detected was 13-desMe-spirolide C and this supported the association with A. ostenfeldii in the field. This study represents the first integrated molecular, morphological and toxinological analysis of field populations of the genus Alexandrium in the Argentine Sea.
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Affiliation(s)
- Elena Fabro
- División Ficología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del Bosque s/n (B1900FWA), La Plata, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Gastón O Almandoz
- División Ficología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del Bosque s/n (B1900FWA), La Plata, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Martha Ferrario
- División Ficología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del Bosque s/n (B1900FWA), La Plata, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Uwe John
- Alfred Wegener Institut-Helmholtz Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Urban Tillmann
- Alfred Wegener Institut-Helmholtz Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Kerstin Toebe
- Alfred Wegener Institut-Helmholtz Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Bernd Krock
- Alfred Wegener Institut-Helmholtz Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Allan Cembella
- Alfred Wegener Institut-Helmholtz Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570, Bremerhaven, Germany
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Lau WLS, Law IK, Liow GR, Hii KS, Usup G, Lim PT, Leaw CP. Life-history stages of natural bloom populations and the bloom dynamics of a tropical Asian ribotype of Alexandrium minutum. HARMFUL ALGAE 2017; 70:52-63. [PMID: 29169568 DOI: 10.1016/j.hal.2017.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 10/30/2017] [Accepted: 10/30/2017] [Indexed: 06/07/2023]
Abstract
In 2015, a remarkably high density bloom of Alexandrium minutum occurred in Sungai Geting, a semi-enclosed lagoon situated in the northeast of Peninsular Malaysia, causing severe discoloration and contaminated the benthic clams (Polymesoda). Plankton and water samples were collected to investigate the mechanisms of bloom development of this toxic species. Analysis of bloom samples using flow cytometry indicated that the bloom was initiated by the process of active excystment, as planomycetes (>4C cells) were observed in the early stage of the bloom. Increase in planozygotes (2C cells) was evident during the middle stage of the bloom, coinciding with an abrupt decrease in salinity and increase of temperature. The bloom was sustained through the combination of binary division of vegetative cells, division of planozygotes, and cyst germination through continuous excystment. Nutrient depletion followed by precipitation subsequently caused the bloom to terminate. This study provides the first continuous record of in situ life-cycle stages of a natural bloom population of A. minutum through a complete bloom cycle. The event has provided a fundamental understanding of the pelagic life-cycle stages of this tropical dinoflagellate, and demonstrated a unique bloom development characteristic shared among toxic Alexandrium species in coastal embayments.
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Affiliation(s)
- Winnie Lik Sing Lau
- Institute of Ocean and Earth Sciences, University of Malaya, 16310 Bachok, Kelantan, Malaysia
| | - Ing Kuo Law
- Institute of Ocean and Earth Sciences, University of Malaya, 16310 Bachok, Kelantan, Malaysia
| | - Guat Ru Liow
- Institute of Ocean and Earth Sciences, University of Malaya, 16310 Bachok, Kelantan, Malaysia
| | - Kieng Soon Hii
- Institute of Ocean and Earth Sciences, University of Malaya, 16310 Bachok, Kelantan, Malaysia
| | - Gires Usup
- Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Malaysia
| | - Po Teen Lim
- Institute of Ocean and Earth Sciences, University of Malaya, 16310 Bachok, Kelantan, Malaysia.
| | - Chui Pin Leaw
- Institute of Ocean and Earth Sciences, University of Malaya, 16310 Bachok, Kelantan, Malaysia.
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Wiese M, Murray SA, Alvin A, Neilan BA. Gene expression and molecular evolution of sxtA4 in a saxitoxin producing dinoflagellate Alexandrium catenella. Toxicon 2014; 92:102-12. [PMID: 25301480 DOI: 10.1016/j.toxicon.2014.09.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 09/25/2014] [Indexed: 10/24/2022]
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.
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Affiliation(s)
- Maria Wiese
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia.
| | - Shauna A Murray
- Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia; Plant Functional Biology and Climate Change Cluster, University of Technology, Sydney, NSW 2007, Australia
| | - Alfonsus Alvin
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Brett A Neilan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia.
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Wiese M, Murray SA, Alvin A, Neilan BA. WITHDRAWN: Gene expression and molecular evolution of sxtA4 in a saxitoxin producing dinoflagellate Alexandrium catenella. Toxicon 2014:S0041-0101(14)00193-7. [PMID: 25080311 DOI: 10.1016/j.toxicon.2014.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 07/08/2014] [Accepted: 07/15/2014] [Indexed: 10/25/2022]
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 http://www.elsevier.com/locate/withdrawalpolicy.
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Affiliation(s)
- Maria Wiese
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia
| | - Shauna A Murray
- Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia; Plant Functional Biology and Climate Change Cluster, University of Technology, Sydney, NSW 2007, Australia
| | - Alfonsus Alvin
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia
| | - Brett A Neilan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Sydney Institute of Marine Science, Chowder Bay Rd, Mosman, NSW 2088, Australia
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Roje-Busatto R, Ujević I. PSP toxins profile in ascidian Microcosmus vulgaris (Heller, 1877) after human poisoning in Croatia (Adriatic Sea). Toxicon 2014; 79:28-36. [PMID: 24418175 DOI: 10.1016/j.toxicon.2013.12.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/30/2013] [Accepted: 12/31/2013] [Indexed: 12/01/2022]
Abstract
Toxins known to cause Paralytic Shellfish Poisoning (PSP) syndrome in humans that can have serious economic consequences for aquaculture were determined in ascidians of the genus Microcosmus. Significant concentrations of toxins were confirmed in all tested samples collected from the western coast of Istria Peninsula (Adriatic Sea, Croatia) when six people were poisoned following the consumption of fresh ascidians. Several species of bivalves that were under continuous monitoring had not accumulated PSP toxins although they were exposed to the same environmental conditions over the survey period. In the present study, HPLC-FLD with pre-column oxidation of PSP toxins has been carried out to provide evidence for the first human intoxication due to consumption of PSP toxic ascidians (Microcosmus vulgaris, Heller, 1877) harvested from the Adriatic Sea. Qualitative analysis established the presence of six PSP toxins: saxitoxin (STX), decarbamoylsaxitoxin (dcSTX), gonyautoxins 2 and 3 (GTX2,3), decarbamoylgonyautoxins 2 and 3 (dcGTX2,3), gonyautoxin 5 (GTX5) and N-sulfocarbamoylgonyautoxins 1 and 2 (C1,2), while quantitative analysis suggested STX and GTX2,3 as dominant toxin types and the ones that contribute the most to the overall toxicity of these samples with concentrations near the regulatory limit.
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Affiliation(s)
- Romana Roje-Busatto
- Institute of Oceanography and Fisheries, Šetalište I. Meštrovića 63, 21000 Split, P.O. Box 500, Croatia.
| | - Ivana Ujević
- Institute of Oceanography and Fisheries, Šetalište I. Meštrovića 63, 21000 Split, P.O. Box 500, Croatia.
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Lazerges M, Perrot H, Rabehagasoa N, Compère C. Thiol- and biotin-labeled probes for oligonucleotide quartz crystal microbalance biosensors of microalga alexandrium minutum. BIOSENSORS-BASEL 2012; 2:245-54. [PMID: 25585927 PMCID: PMC4263548 DOI: 10.3390/bios2030245] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 06/18/2012] [Accepted: 06/27/2012] [Indexed: 11/16/2022]
Abstract
Two quartz crystal microbalance oligonucleotide biosensors of a toxic microalga gene sequence (Alexandrium Minutum) have been designed. Grafting on a gold surface of 20-base thiol- or biotin-labeled probe, and selective hybridization with the complementary 20-base target, have been monitored in situ with a 27 MHz quartz crystal microbalance under controlled hydrodynamic conditions. The frequency of the set up is stable to within a few hertz, corresponding to the nanogram scale, for three hour experiments. DNA recognition by the two biosensors is efficient and selective. Hybridization kinetic curves indicate that the biosensor designed with the thiol-labeled probe is more sensitive, and that the biosensor designed with the biotin-labeled probe has a shorter time response and a higher hybridization efficiency.
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Affiliation(s)
- Mathieu Lazerges
- Centre National de la Recherche Scientifique (CNRS), Unité Propre de Recherche (UPR) 15, Laboratoire Interfaces et Systèmes Electrochimiques, 4 place Jussieu, Paris 75252, France.
| | - Hubert Perrot
- Centre National de la Recherche Scientifique (CNRS), Unité Propre de Recherche (UPR) 15, Laboratoire Interfaces et Systèmes Electrochimiques, 4 place Jussieu, Paris 75252, France.
| | - Niriniony Rabehagasoa
- Centre National de la Recherche Scientifique (CNRS), Unité Propre de Recherche (UPR) 15, Laboratoire Interfaces et Systèmes Electrochimiques, 4 place Jussieu, Paris 75252, France.
| | - Chantal Compère
- Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre de Brest Service Interfaces et Capteurs, Z.I. pointe du diable, Plouzané 29280, France.
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15
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Pistocchi R, Guerrini F, Pezzolesi L, Riccardi M, Vanucci S, Ciminiello P, Dell’Aversano C, Forino M, Fattorusso E, Tartaglione L, Milandri A, Pompei M, Cangini M, Pigozzi S, Riccardi E. Toxin levels and profiles in microalgae from the north-Western Adriatic Sea--15 years of studies on cultured species. Mar Drugs 2012; 10:140-162. [PMID: 22363227 PMCID: PMC3280532 DOI: 10.3390/md10010140] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 12/29/2011] [Accepted: 01/05/2012] [Indexed: 12/03/2022] Open
Abstract
The Northern Adriatic Sea is the area of the Mediterranean Sea where eutrophication and episodes related to harmful algae have occurred most frequently since the 1970s. In this area, which is highly exploited for mollusk farming, the first occurrence of human intoxication due to shellfish consumption occurred in 1989, nearly 10 years later than other countries in Europe and worldwide that had faced similar problems. Until 1997, Adriatic mollusks had been found to be contaminated mostly by diarrhetic shellfish poisoning toxins (i.e., okadaic acid and dinophysistoxins) that, along with paralytic shellfish poisoning toxins (i.e., saxitoxins), constitute the most common marine biotoxins. Only once, in 1994, a toxic outbreak was related to the occurrence of paralytic shellfish poisoning toxins in the Adriatic coastal waters. Moreover, in the past 15 years, the Adriatic Sea has been characterized by the presence of toxic or potentially toxic algae, not highly widespread outside Europe, such as species producing yessotoxins (i.e., Protoceratium reticulatum, Gonyaulax spinifera and Lingulodinium polyedrum), recurrent blooms of the potentially ichthyotoxic species Fibrocapsa japonica and, recently, by blooms of palytoxin-like producing species of the Ostreopsis genus. This review is aimed at integrating monitoring data on toxin spectra and levels in mussels farmed along the coast of the Emilia-Romagna region with laboratory studies performed on the species involved in the production of those toxins; toxicity studies on toxic or potentially toxic species that have recently appeared in this area are also reviewed. Overall, reviewed data are related to: (i) the yessotoxins producing species P. reticulatum, G. spinifera and L. polyedrum, highlighting genetic and toxic characteristics; (ii) Adriatic strains of Alexandrium minutum, Alexandrium ostenfeldii and Prorocentrum lima whose toxic profiles are compared with those of strains of different geographic origins; (iii) F. japonica and Ostreopsis cf. ovata toxicity. Moreover, new data concerning domoic acid production by a Pseudo-nitzschia multistriata strain, toxicity investigations on a Prorocentrum cf. levis, and on presumably ichthyotoxic species, Heterosigma akashiwo and Chattonella cf. subsalsa, are also reported.
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Affiliation(s)
- Rossella Pistocchi
- Interdepartmental Center for Research in Environmental Sciences, University of Bologna, Via Sant’Alberto 163, Ravenna 48123, Italy; (F.G.); (L.P.); (M.R.)
- Author to whom correspondence should be addressed; ; Tel.: +39-0544-937376; Fax: +39-0544-937411
| | - Franca Guerrini
- Interdepartmental Center for Research in Environmental Sciences, University of Bologna, Via Sant’Alberto 163, Ravenna 48123, Italy; (F.G.); (L.P.); (M.R.)
| | - Laura Pezzolesi
- Interdepartmental Center for Research in Environmental Sciences, University of Bologna, Via Sant’Alberto 163, Ravenna 48123, Italy; (F.G.); (L.P.); (M.R.)
| | - Manuela Riccardi
- Interdepartmental Center for Research in Environmental Sciences, University of Bologna, Via Sant’Alberto 163, Ravenna 48123, Italy; (F.G.); (L.P.); (M.R.)
| | - Silvana Vanucci
- Department of Animal Biology and Marine Ecology, University of Messina, Salita Sperone 31, Agata, Messina 98166, Italy;
| | - Patrizia Ciminiello
- Department of Chemistry of Natural Substances, University of Napoli “Federico II”, Via D. Montesano 49, Napoli 80131, Italy; (P.C.); (C.D.); (M.F.); (E.F.); (L.T.)
| | - Carmela Dell’Aversano
- Department of Chemistry of Natural Substances, University of Napoli “Federico II”, Via D. Montesano 49, Napoli 80131, Italy; (P.C.); (C.D.); (M.F.); (E.F.); (L.T.)
| | - Martino Forino
- Department of Chemistry of Natural Substances, University of Napoli “Federico II”, Via D. Montesano 49, Napoli 80131, Italy; (P.C.); (C.D.); (M.F.); (E.F.); (L.T.)
| | - Ernesto Fattorusso
- Department of Chemistry of Natural Substances, University of Napoli “Federico II”, Via D. Montesano 49, Napoli 80131, Italy; (P.C.); (C.D.); (M.F.); (E.F.); (L.T.)
| | - Luciana Tartaglione
- Department of Chemistry of Natural Substances, University of Napoli “Federico II”, Via D. Montesano 49, Napoli 80131, Italy; (P.C.); (C.D.); (M.F.); (E.F.); (L.T.)
| | - Anna Milandri
- National Reference Laboratory for Marine Biotoxins, Fondazione Centro Ricerche Marine, Viale A. Vespucci 2, Cesenatico (FC) 47042, Italy; (A.M.); (M.P.); (M.C.); (S.P.); (E.R.)
| | - Marinella Pompei
- National Reference Laboratory for Marine Biotoxins, Fondazione Centro Ricerche Marine, Viale A. Vespucci 2, Cesenatico (FC) 47042, Italy; (A.M.); (M.P.); (M.C.); (S.P.); (E.R.)
| | - Monica Cangini
- National Reference Laboratory for Marine Biotoxins, Fondazione Centro Ricerche Marine, Viale A. Vespucci 2, Cesenatico (FC) 47042, Italy; (A.M.); (M.P.); (M.C.); (S.P.); (E.R.)
| | - Silvia Pigozzi
- National Reference Laboratory for Marine Biotoxins, Fondazione Centro Ricerche Marine, Viale A. Vespucci 2, Cesenatico (FC) 47042, Italy; (A.M.); (M.P.); (M.C.); (S.P.); (E.R.)
| | - Elena Riccardi
- National Reference Laboratory for Marine Biotoxins, Fondazione Centro Ricerche Marine, Viale A. Vespucci 2, Cesenatico (FC) 47042, Italy; (A.M.); (M.P.); (M.C.); (S.P.); (E.R.)
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Haberkorn H, Lambert C, Le Goïc N, Guéguen M, Moal J, Palacios E, Lassus P, Soudant P. Effects of Alexandrium minutum exposure upon physiological and hematological variables of diploid and triploid oysters, Crassostrea gigas. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 97:96-108. [PMID: 20045204 DOI: 10.1016/j.aquatox.2009.12.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 12/01/2009] [Accepted: 12/04/2009] [Indexed: 05/28/2023]
Abstract
The effects of an artificial bloom of the toxin-producing dinoflagellate, Alexandrium minutum, upon physiological parameters of the Pacific oyster, Crassostrea gigas, were assessed. Diploid and triploid oysters were exposed to cultured A. minutum and compared to control diploid and triploid oysters fed T. Isochrysis. Experiments were repeated twice, in April and mid-May 2007, to investigate effects of maturation stage on oyster responses to A. minutum exposure. Oyster maturation stage, Paralytic Shellfish Toxin (PST) accumulation, as well as several digestive gland and hematological variables, were assessed at the ends of the exposures. In both experiments, triploid oysters accumulated more PSTs (approximately twice) than diploid oysters. Significant differences, in terms of phenoloxidase activity (PO) and reactive oxygen species (ROS) production of hemocytes, were observed between A. minutum-exposed and non-exposed oysters. PO in hemocytes was lower in oysters exposed to A. minutum than in control oysters in an early maturation stage (diploids and triploids in April experiment and triploids in May experiment), but this contrast was reversed in ripe oysters (diploids in May experiment). In the April experiment, granulocytes of oysters exposed to A. minutum produced more ROS than those of control oysters; however, in the May experiment, ROS production of granulocytes was lower in A. minutum-exposed oysters. Moreover, significant decreases in free fatty acid, monoacylglycerol, and diacylglycerol contents in digestive glands of oysters exposed to A. minutum were observed. Concurrently, the ratio of reserve lipids (triacylglycerol, ether glycerides and sterol esters) to structural lipids (sterols) decreased upon A. minutum exposure in both experiments. Also, several physiological responses to A. minutum exposure appeared to be modulated by maturation stage as well as ploidy of the oysters.
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Affiliation(s)
- Hansy Haberkorn
- Laboratoire des Sciences de l'Environnement Marin, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, Place Copernic, Technopôle Brest-Iroise, 29280 Plouzané, France
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18
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McCauley LAR, Erdner DL, Nagai S, Richlen ML, Anderson DM. BIOGEOGRAPHIC ANALYSIS OF THE GLOBALLY DISTRIBUTED HARMFUL ALGAL BLOOM SPECIES ALEXANDRIUM MINUTUM (DINOPHYCEAE) BASED ON rRNA GENE SEQUENCES AND MICROSATELLITE MARKERS(1). JOURNAL OF PHYCOLOGY 2009; 45:454-63. [PMID: 27033824 PMCID: PMC5488690 DOI: 10.1111/j.1529-8817.2009.00650.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The toxic dinoflagellate Alexandrium minutum Halim is one of three species that comprise the "minutum" species complex. This complex is notable due to its role in the etiology of paralytic shellfish poisoning (PSP). Recent increases in PSP incidence and the geographic expansion of toxin-producing Alexandrium dinoflagellates have prompted the intensive examination of genetic relationships among globally distributed strains to address questions regarding their present distribution and reasons for their apparent increase. The biogeography of A. minutum was studied using large subunit ribosomal DNA gene (LSU rRNA) and internal transcribed spacer (ITS) sequences and genotypic data from 12 microsatellite loci. rRNA gene and ITS sequencing data distinguished between two clades, herein termed the "Global" and the "Pacific"; however, little to no resolution was seen within each clade. Genotypic data from 12 microsatellite loci provided additional information regarding genetic relationships within the Global clade, but it was not possible to amplify DNA from the Pacific clade using these markers. With the exception of isolates from Italy and Spain, strains generally clustered according to origin, revealing geographic structuring within the Global clade. Additionally, no evidence supported the separation of A. lusitanicum and A. minutum as different species. With the use of microsatellites, it is now possible to initiate studies on the origin, history, and genetic heterogeneity of A. minutum that were not previously possible using only rRNA gene sequence data. This study demonstrates the power of combining a marker with intermediate resolution (rRNA sequences) with finer-scale markers (microsatellites) to examine intraspecies variability among globally distributed isolates and represents the first effort to employ this technique in A. minutum.
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Affiliation(s)
| | - Deana L. Erdner
- University of Texas at Austin, Marine Science Institute, Port Aransas, Texas 78373, USA
| | - Satoshi Nagai
- National Research Institute of Fisheries and Environment of Inland Sea, 2-17-5 Maruishi, Hatsukaichi, Hiroshima 739-0452, Japan
| | - Mindy L. Richlen
- Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
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Zooplankton interactions with toxic phytoplankton: Some implications for food web studies and algal defence strategies of feeding selectivity behaviour, toxin dilution and phytoplankton population diversity. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2007. [DOI: 10.1016/j.actao.2007.05.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Touzet N, Franco JM, Raine R. Influence of inorganic nutrition on growth and PSP toxin production of Alexandrium minutum (Dinophyceae) from Cork Harbour, Ireland. Toxicon 2007; 50:106-19. [PMID: 17452045 DOI: 10.1016/j.toxicon.2007.03.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 03/01/2007] [Accepted: 03/02/2007] [Indexed: 11/30/2022]
Abstract
The physiological response of the PSP toxin producing dinoflagellate Alexandrium minutum isolated from the Irish coast was assessed after modulating the initial concentrations of nitrate and phosphate in batch cultures. The cell growth in cultures of strain CK.A02 was primarily controlled by nitrate availability. In all experiments, only gonyautoxins 2 and 3 (GTX2 and 3) were synthesized along the different growth phases, with GTX3 dominating ( approximately 80%) at all stages, making the GTX2-3 toxin profile a possible population marker of A. minutum in Cork Harbour. The cellular toxin quotas remained low and relatively stable at around 2 pg cell(-1), except when high N:P ratios were initially used for culture inoculations; in these conditions PSP toxins accumulated up to 14 pg cell(-1). Due to the composition of the toxin profile, the toxicity of strain CK.A02 was generally relatively low (from 1.1 to 1.7 pg STX eqcell(-1)) in comparison with strains from other geographic areas except when phosphate limiting culture conditions were applied (maximum of 12.5 pg STX eq cell(-1)). Results showed that sufficient soluble protein quotas were necessary to observe the intra-cellular accumulation of PSP toxins in phosphate limiting conditions, highlighting also the requirement of adequate nitrogen supplies. The possible existence of localized toxicity hot spots in the field, linked to the accumulation of PSP toxins within A. minutum cells as a metabolic response to adverse environmental conditions, could potentially increase risks for shellfish farming operations.
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Affiliation(s)
- Nicolas Touzet
- The Martin Ryan Institute, National University of Ireland, Galway, Ireland.
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22
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Touzet N, Franco JM, Raine R. Characterization of nontoxic and toxin-producing strains of Alexandrium minutum (Dinophyceae) in Irish coastal waters. Appl Environ Microbiol 2007; 73:3333-42. [PMID: 17337562 PMCID: PMC1907102 DOI: 10.1128/aem.02161-06] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Accepted: 02/19/2007] [Indexed: 11/20/2022] Open
Abstract
A comparative analysis of the morphology, toxin composition, and ribosomal DNA (rDNA) sequences was performed on a suite of clonal cultures of the potentially toxic dinoflagellate Alexandrium minutum Halim. These were established from resting cysts or vegetative cells isolated from sediment and water samples taken from the south and west coasts of Ireland. Results revealed that strains were indistinguishable, both morphologically and through the sequencing of the D1-D2 domain of the large subunit and the ITS1-5.8S-ITS2 regions of the rDNA. High-performance liquid chromatography fluorescence detection analysis, however, showed that only strains derived from retentive inlets on the southern Irish coast synthesized paralytic shellfish poisoning (PSP) toxins (GTX2 and GTX3), whereas all strains of A. minutum isolated from the west coast were nontoxic. Toxin analysis of net hauls, taken when A. minutum vegetative cells were in the water column, revealed no PSP toxins in samples from Killary Harbor (western coast), whereas GTX2 and GTX3 were detected in samples from Cork Harbor (southern coast). These results confirm the identity of A. minutum as the most probable causative organism for historical occurrences of contamination of shellfish with PSP toxins in Cork Harbor. Finally, random amplification of polymorphic DNA was carried out to determine the degree of polymorphism among strains. The analysis showed that all toxic strains from Cork Harbor clustered together and that a separate cluster grouped all nontoxic strains from the western coast.
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MESH Headings
- Animals
- Cluster Analysis
- DNA Fingerprinting
- DNA, Protozoan/chemistry
- DNA, Protozoan/genetics
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- DNA, Ribosomal Spacer
- Dinoflagellida/classification
- Dinoflagellida/cytology
- Dinoflagellida/isolation & purification
- Dinoflagellida/physiology
- Genes, rRNA
- Genetic Variation
- Ireland
- Marine Toxins/biosynthesis
- Microscopy, Fluorescence
- Molecular Sequence Data
- Phylogeny
- Polymorphism, Genetic
- RNA, Ribosomal, 28S/genetics
- RNA, Ribosomal, 5.8S/genetics
- Random Amplified Polymorphic DNA Technique
- Seawater/microbiology
- Sequence Homology, Nucleic Acid
- Water Microbiology
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Affiliation(s)
- Nicolas Touzet
- The Martin Ryan Institute, National University of Ireland, Galway, Ireland.
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Wang DZ, Zhang SG, Gu HF, Chan LL, Hong HS. Paralytic shellfish toxin profiles and toxin variability of the genus Alexandrium (Dinophyceae) isolated from the Southeast China Sea. Toxicon 2006; 48:138-51. [PMID: 16859722 DOI: 10.1016/j.toxicon.2006.04.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2005] [Revised: 03/23/2006] [Accepted: 04/07/2006] [Indexed: 11/20/2022]
Abstract
Paralytic shellfish toxin (PST) profiles of 16 Alexandrium isolates from the Southeast China Sea were analyzed by high-pressure liquid chromatography. Toxin content and composition of three A. tamarense isolates, ATDH01, ATGX02 and ATMJ02, were also investigated at different growth phases and under various culture conditions. Our results showed that six strains of A. affine were non-toxic, while 10 strains of A. tamarense and A. catenella were toxic. These toxic isolates grown in the same culture conditions consistently produced an unusually high proportion of the N-sulfocarbamoyl toxin C1/2 (around 60-80% of total toxins) and medium amounts of gonyautoxin GTX5 (around 15-30% of total) with only trace quantities (<5% of total) of other saxitoxin derivatives (i.e. GTX1, GTX3, GTX4 and neoSTX). The toxin composition of three A. tamarense isolates did not vary with the growth phases, although higher toxin contents (Qt, fmolcell(-1)) were found in the exponential phase. Variations in temperature, salinity and nutrient levels affected toxin content of three A. tamarense isolates but they did not have pronounced effects on the toxin composition (mole %). These results indicate that toxin composition remained relatively constant under various culture conditions, suggesting that toxin composition could be used as a stable biomarker for the Alexandrium species in this region. However, comparison of toxin profiles between isolates from different localities require special caution since isolates even from the same region can have distinct toxin profiles.
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Affiliation(s)
- Da-Zhi Wang
- State Key Laboratory of Marine Environmental Science/Environmental Science Research Center, Xiamen University, Xiamen 361005, People's Republic of China.
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Llewellyn LE. Saxitoxin, a toxic marine natural product that targets a multitude of receptors. Nat Prod Rep 2006; 23:200-22. [PMID: 16572228 DOI: 10.1039/b501296c] [Citation(s) in RCA: 238] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Saxitoxin (STX) was discovered early last century and can contaminate seafood and drinking water, and over time has become an invaluable research tool and an internationally regulated chemical weapon. Among natural products, toxins obtain a unique reputation from their high affinity and selectivity for their target pharmacological receptor, which for STX has long been considered to only be the voltage gated sodium channel. In recent times however, STX has been discovered to also bind to calcium and potassium channels, neuronal nitric oxide synthase, STX metabolizing enzymes and two circulatory fluid proteins, namely a transferrin-like family of proteins and a unique protein found in the blood of pufferfish.
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Lim PT, Ogata T. Salinity effect on growth and toxin production of four tropical Alexandrium species (Dinophyceae). Toxicon 2005; 45:699-710. [PMID: 15804519 DOI: 10.1016/j.toxicon.2005.01.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 12/27/2004] [Accepted: 01/10/2005] [Indexed: 11/16/2022]
Abstract
Four tropical PSP toxins-producing dinoflagellates, Alexandrium minutum, Alexandrium tamiyavanichii, Alexandrium tamarense and Alexandrium peruvianum from Malaysian waters were studied to investigate the influences of salinity on growth and toxin production. Experiments were conducted on constant temperature 25 degrees C, 140 microE mol m(-2) s(-1) and under 14:10 light:dark photo-cycle with salinity ranged from 2 to 30 psu. The PSP-toxin congeners, GTX 1-6, STX, dcSTX, NEO and C1-C2 were analysed by high performance liquid chromatography. Salinity tolerance of the four species in decreasing order is A. minutum>A. peruvianum>A. tamarense>A. tamiyavanichii. Specific growth rates and maximum densities varied among these species with A. minutum recorded as the highest, 0.5 day(-1) and 6 x 10(4) cells L(-1). Toxin content decreased with elevated salinities in A. minutum, the highest toxin content was about 12 fmole cell(-1) at 5 psu. In A. tamiyavanichii, toxin content peaked at optimal growth salinity (20 and 25 psu). Toxin content of A. tamarense, somehow peaked at sub-optimal growth salinity (15 and 30 psu). Results of this study implied that salinity fluctuation not only influenced the growth physiology but also toxin production of these species.
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Affiliation(s)
- Po-Teen Lim
- School of Fisheries Science, Kitasato University, Sanriku, Ofunato, Iwate 022-0101, Japan.
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Metfies K, Huljic S, Lange M, Medlin LK. Electrochemical detection of the toxic dinoflagellate Alexandrium ostenfeldii with a DNA-biosensor. Biosens Bioelectron 2005; 20:1349-57. [PMID: 15590289 DOI: 10.1016/j.bios.2004.05.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 05/19/2004] [Accepted: 05/20/2004] [Indexed: 11/21/2022]
Abstract
The steady rise of observations of harmful or toxic algal blooms throughout the world in the past decades constitute a menace for coastal ecosystems and human interests. As a consequence, a number of programs have been launched to monitor the occurrence of harmful and toxic algae. However, the identification is currently done by microscopic examination, which requires a broad taxonomic knowledge, expensive equipment and is very time consuming. In order to facilitate the identification of toxic algae, an inexpensive and easy-to-handle DNA-biosensor has been adapted for the electrochemical detection of the toxic dinoflagellate Alexandrium ostenfeldii. The detection of the toxic algae is based on a sandwich hybridisation, which is carried out on a disposable sensor chip. A set of two probes for the species-specific identification of A. ostenfeldii was developed. The specificity of the probes could be shown in dot-blot hybridisations and with the DNA-biosensor. The sensitivity of the DNA-biosensor was optimised with respect to hybridisation temperature and NaCl-concentration and a significant increase of the sensitivity of the DNA-biosensor could be obtained by a fragmentation of the rRNA prior to the hybridisation and by adding a helper oligonucleotide, which binds in close proximity to the probes to the hybridisation.
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Affiliation(s)
- Katja Metfies
- Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany.
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Abstract
For an algal bloom to develop, the growth rate of the bloom-forming species must exceed the sum of all loss processes. Among these loss processes, grazing is generally believed to be one of the more important factors. Based on numerous field studies, it is now recognized that microzooplankton are dominant consumers of phytoplankton in both open ocean and coastal waters. Heterotrophic protists, a major component of microzooplankton communities, constitute a vast complex of diverse feeding strategies and behavior which allow them access to even the larger phytoplankton species. A number of laboratory studies have shown the capability of different protistan species to feed and grow on bloom-forming algal species. Because of short generation times, their ability for fast reaction to short-term variation in food conditions enables phagotrophic protists to fulfill the function of a heterotrophic buffer, which might balance the flow of matter in case of phytoplankton blooms. The importance of grazing as a control of microalgae becomes most apparent by its failure; if community grazing controls initial stages of bloom development, there simply is no bloom. However, if a certain algal species is difficult to graze, e.g. due to specific defense mechanisms, reduced grazing pressure will certainly favor bloom development. The present contribution will provide a general overview on the interactions between planktonic microalgae and protozoan grazers with special emphasis on species-specific interactions and algal defense strategies against protozoan grazers.
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Affiliation(s)
- Urban Tillmann
- Alfred Wegener Institute, Am Handelshafen 12, D-27570 Bremerhaven, Germany.
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Chou HN, Chen YM, Chen CY. Variety of PSP toxins in four culture strains of Alexandrium minutum collected from southern Taiwan. Toxicon 2004; 43:337-40. [PMID: 15033333 DOI: 10.1016/j.toxicon.2004.01.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2003] [Accepted: 01/06/2004] [Indexed: 11/18/2022]
Abstract
Paralytic shellfish poisoning (PSP) toxin profiles were compared among four culture strains of Alexandrium minutum. GTX-1, 2, 3 and 4 are the PSP toxins that occur in A. minutum, and other PSP toxins were not detected. When comparing the toxin profile of four A. minutum strains, GTX1 and 4 were the major toxins in Amtk1, Amtk2, and Amtk4, but in Amtk7, GTX3 and 2 were the major toxins. The results indicate that strains with various toxin profiles exist in southern Taiwan, and suggest that the comparison of the toxin profiles between strains at different localities is difficult. Additionally, the toxin profiles of A. minutum strains cultured in the same environment were different, suggesting that it was owing to the intrinsic nature of toxic algae.
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Affiliation(s)
- Hong Nong Chou
- Institute of Fisheries Science, National Taiwan University, Taipei 10617, Taiwan, ROC
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Hsieh DP, Wang D, Chang GH. Laboratory bioproduction of paralytic shellfish toxins in dinoflagellates. ADVANCES IN APPLIED MICROBIOLOGY 2002; 49:85-110. [PMID: 11757352 DOI: 10.1016/s0065-2164(01)49010-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- D P Hsieh
- Department of Biology, Hong Kong University of Science and Technology, Clear Water Way, Kowloon, Hong Kong, People's Republic of China
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Tengs T, Bowers HA, Ziman AP, Stoecker DK, Oldach DW. Genetic polymorphism in Gymnodinium galatheanum chloroplast DNA sequences and development of a molecular detection assay. Mol Ecol 2001; 10:515-23. [PMID: 11298964 DOI: 10.1046/j.1365-294x.2001.01223.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Nuclear and chloroplast-encoded small subunit ribosomal DNA sequences were obtained from several strains of the toxic dinoflagellate Gymnodinium galatheanum. Phylogenetic analyses and comparison of sequences indicate that the chloroplast sequences show a higher degree of sequence divergence than the nuclear homologue. The chloroplast sequences were chosen as targets for the development of a 5'--3' exonuclease assay for detection of the organism. The assay has a very high degree of specificity and has been used to screen environmental water samples from a fish farm where the presence of this dinoflagellate species has previously been associated with fish kills. Various hypotheses for the derived nature of the chloroplast sequences are discussed, as well as what is known about the toxicity of the species.
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Affiliation(s)
- T Tengs
- Institute of Human Virology, University of Maryland at Baltimore, 725 West Lombard Street, Baltimore, MD 21201, USA
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Hwang DF, Lu YH. Influence of environmental and nutritional factors on growth, toxicity, and toxin profile of dinoflagellate Alexandrium minutum. Toxicon 2000; 38:1491-503. [PMID: 10775750 DOI: 10.1016/s0041-0101(00)00080-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The toxic dinoflagellate Alexandrium minutum T1 was isolated from southern Taiwan in February 1996, grown under various environmental and nutritional conditions, and then examined for growth, toxicity, and toxin profile. It was found that the optimal environmental conditions for cell growth and toxin production of A. minutum T1 was as follows: temperature 25 degrees C, pH 7.5, light strength 120 microEm(-2) s(-1), and salinity 15 ppt. The optimal level of nutrients supplemented in the 50% natural seawater medium was as follows: phosphate 0.002%, nitrate 0.01%, cupric ion 5.0 ppb, ferric ion 270 ppb and humic acid free. Both cell toxicity and total toxicity reached the maximum level at the post-stationary growth phase and decreased quickly. The toxic components of A. minutum T1 were assayed by high performance liquid chromatography, and found to be gonyautoxin (GTX) 1-4 only. Among these four toxin components, toxins GTX 1 and 4 were the predominant components throughout the growth curve when the cells were grown in the optimal environmental and nutritional conditions. But toxins GTX 2 and 3 increased when the cells were cultured in high salinity medium.
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Affiliation(s)
- D F Hwang
- Department of Food Science, National Taiwan Ocean University,¿ Keelung, Taiwan.
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Perovic S, Tretter L, Brümmer F, Wetzler C, Brenner J, Donner G, Schröder HC, Müller WE. Dinoflagellates from marine algal blooms produce neurotoxic compounds: effects on free calcium levels in neuronal cells and synaptosomes. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2000; 8:83-94. [PMID: 10867367 DOI: 10.1016/s1382-6689(99)00035-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this report, evidence is presented that the marine unicellular eukaryotic dinoflagellates can cause neurotoxicity very likely by an increase in intracellular free calcium ions ([Ca(2+)](i)). Determinations of the effects of culture supernatants from different clones of the dinoflagellate Alexandrium sp. isolated from algal blooms on the viability of rat primary neuronal cells revealed that all clones tested were toxic for these cells. In addition, all Alexandrium clones tested, except for A. ostenfeldii BAH ME-141, were found to be toxic for rat pheochromocytoma PC12 cells. No toxicity was observed for culture supernatants from Gonyaulax and Coolia monotis. Calcium ions are important in the process of apoptotic cell death; our studies revealed that the dinoflagellate supernatants from A. lusitanicum K2, A. lusitanicum BAH ME-091, and A. tamarense 1M caused an increase in [Ca(2+)](i) levels in both PC12 cells and primary neuronal cells. These dinoflagellate supernatants, as well as the A. tamarense ccmp 115 supernatant, were found to cause also an increase in free calcium concentration in isolated synaptosomes. Our results suggest that the neurotoxic effects of certain dinoflagellate supernatants may be associated with disturbances in [Ca(2+)](i) levels.
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Affiliation(s)
- S Perovic
- Institut für Physiologische Chemie, Abteilung für Angewandte Molekularbiologie, Universität Mainz, Duesbergweg 6, D-55099, Mainz, Germany
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Kerr DS, Briggs DM, Saba HI. A neurophysiological method of rapid detection and analysis of marine algal toxins. Toxicon 1999; 37:1803-25. [PMID: 10519657 DOI: 10.1016/s0041-0101(99)00124-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have examined the effectiveness of the in vitro rat hippocampal slice preparation as a means of rapidly and specifically detecting the marine algal toxins saxitoxin, brevetoxin, and domoic acid and have identified toxin-specific electrophysiological signatures for each. Brevetoxin (PbTX3, 50-200 nM) produced a significant reduction in orthodromic population spike amplitude which was quick to reverse during a 50 min wash-out, while antidromic population spikes and field EPSPs exhibited only slight reductions, and fibre spiof orthodrokes showed no change at all. Domoic acid (100 nM) produced a robust, reversible increase in amplitude mic spikes, and the appearance of multiple spikes (i.e., epileptiform activity) within minutes of toxin wash-in. Other notable features of the domoic acid signature included a significant decrease in amplitude of the field EPSPs, and a complete absence of effect on either antidromic or fibre spikes. Fifty nanomolar saxitoxin (PSP) abolished all responses in all slices. Only antidromic spikes showed any recovery during wash-out. Field EPSP and fiber spike analysis further demonstrated that the preparation is capable of reliably detecting saxitoxin in a linearly responsive fashion at toxin concentrations of 25-200 nM, and tests of naturally contaminated shellfish confirmed the utility of this assay as a screening method for PSP. Our findings suggest that the in vitro hippocampal slice preparation has potential in the detection and analysis of three marine algal toxins important to the shellfish industry.
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Affiliation(s)
- D S Kerr
- Department of Pharmacology, University of Otago School of Medicine, Dunedin, New Zealand.
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