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Gwinn JK, Robertson A, Ivanova L, Fæste CK, Kryuchkov F, Uhlig S. Identification and cross-species comparison of in vitro phase I brevetoxin (BTX-2) metabolites in northern Gulf of Mexico fish and human liver microsomes by UHPLC-HRMS(/MS). Toxicon X 2023; 19:100168. [PMID: 37483846 PMCID: PMC10362319 DOI: 10.1016/j.toxcx.2023.100168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 06/07/2023] [Accepted: 06/21/2023] [Indexed: 07/25/2023] Open
Abstract
Brevetoxins (BTX) are a group of marine neurotoxins produced by the harmful alga Karenia brevis. Numerous studies have shown that BTX are rapidly accumulated and metabolized in shellfish and mammals. However, there are only limited data on BTX metabolism in fish, despite growing evidence that fish serve as vectors for BTX transfer in marine food webs. In this study, we aimed to investigate the in vitro biotransformation of BTX-2, the major constituent of BTX profiles in K. brevis, in several species of northern Gulf of Mexico fish. Metabolism assays were performed using hepatic microsomes prepared in-house as well as commercially available human microsomes for comparison, focusing on phase I reactions mediated by cytochrome P450 monooxygenase (CYP) enzymes. Samples were analyzed by UHPLC-HRMS(/MS) to monitor BTX-2 depletion and characterize BTX metabolites based on MS/MS fragmentation pathways. Our results showed that both fish and human liver microsomes rapidly depleted BTX-2, resulting in a 72-99% reduction within 1 h of incubation. We observed the simultaneous production of 22 metabolites functionalized by reductions, oxidations, and other phase I reactions. We were able to identify the previously described congeners BTX-3 and BTX-B5, and tentatively identified BTX-9, 41,43-dihydro-BTX-2, several A-ring hydrolysis products, as well as several novel metabolites. Our results confirmed that fish are capable of similar BTX biotransformation reactions as reported for shellfish and mammals, but comparison of metabolite formation across the tested species suggested considerable interspecific variation in BTX-2 metabolism potentially leading to divergent BTX profiles. We additionally observed non-enzymatic formation of BTX-2 and BTX-3 glutathione conjugates. Collectively, these findings have important implications for determining the ecotoxicological fate of BTX in marine food webs.
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Affiliation(s)
- Jessica Kay Gwinn
- University of South Alabama, School of Marine and Environmental Sciences, Mobile, AL, 36688, United States
- Dauphin Island Sea Lab, Dauphin Island, AL, 36528, United States
| | - Alison Robertson
- University of South Alabama, School of Marine and Environmental Sciences, Mobile, AL, 36688, United States
- Dauphin Island Sea Lab, Dauphin Island, AL, 36528, United States
| | - Lada Ivanova
- Norwegian Veterinary Institute, Toxinology Research Group, NO-1431, Ås, Norway
| | | | - Fedor Kryuchkov
- Norwegian Veterinary Institute, Toxinology Research Group, NO-1431, Ås, Norway
| | - Silvio Uhlig
- Norwegian Veterinary Institute, Toxinology Research Group, NO-1431, Ås, Norway
- Nordic Institute of Dental Materials, NO-0855, Oslo, Norway
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Jobson J, Tsegay PS, Beltran MT, Taher EA, Rein SR, Liu Y, Rein KS. Brevetoxin induces a shift in the redox state of the proteome and unfolded protein response in human lymphoblast cells that can be alleviated with the acrolein scavenger MESNA. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2023; 100:104137. [PMID: 37127110 DOI: 10.1016/j.etap.2023.104137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/24/2023] [Accepted: 04/29/2023] [Indexed: 05/03/2023]
Abstract
Human lymphoblast cells were treated with the marine algal toxin, brevetoxin-2 (PbTx-2), and its effects on the proteome were assessed by redox proteomics using cysteine reactive tandem mass tags (TMT). Additionally, cells were simultaneously treated with PbTx-2 and the antioxidant and acrolein scavenger sodium 2-mercaptoethylsulfonate (MESNA) to determine if MESNA could prevent the proteomic effects of brevetoxin-2. A massive shift in the redox state of the proteome of brevetoxin-2 treated cells was observed. The main pathway affected was genetic information processing. Significantly oxidized proteins included Trx-1, peroxyredoxins (Prxs), ribosomal proteins, and the eukaryotic initiation factor 2 β subunit (eIF2β). Proteins that were overexpressed in brevetoxin-treated cells included four folding chaperones. These effects were diminished in the presence of MESNA indicating that MESNA may act through its antioxidant properties or as a brevetoxin scavenger. These studies provide novel insights into new prophylactics for brevetoxicosis in humans and wildlife.
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Affiliation(s)
- Jordan Jobson
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Pawlos S Tsegay
- Biochemistry Ph.D. Program, Florida International University, Miami, FL 33199, USA
| | - Mayra Tabares Beltran
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Eman A Taher
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Samuel R Rein
- The School District of Philadelphia, Philadelphia, PA 19130, USA
| | - Yuan Liu
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA; Biochemistry Ph.D. Program, Florida International University, Miami, FL 33199, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Kathleen S Rein
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA; Current address: The Water School, Department of Marine and Earth Science and Department of Chemistry and Physics, Florida Gulf Coast University, Fort Myers, FL 33965.
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Shen H, Song X, Zhang Y, Zhang P, Li J, Song W, Yu Z. Profiling of Brevetoxin Metabolites Produced by Karenia brevis 165 Based on Liquid Chromatography-Mass Spectrometry. Toxins (Basel) 2021; 13:toxins13050354. [PMID: 34069292 PMCID: PMC8156667 DOI: 10.3390/toxins13050354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/09/2021] [Accepted: 05/12/2021] [Indexed: 11/16/2022] Open
Abstract
In this study, Karenia brevis 165 (K. brevis 165), a Chinese strain, was used to research brevetoxin (BTX) metabolites. The sample pretreatment method for the enrichment of BTX metabolites in an algal culture medium was improved here. The method for screening and identifying intracellular and extracellular BTX metabolites was established based on liquid chromatography-time-of-flight mass spectrometry (LC-ToF-MS) and liquid chromatography triple quadrupole tandem mass spectrometry (LC-QqQ-MS/MS). The results show that the recovery rates for BTX toxins enriched by a hydrophilic–lipophilic balance (HLB) extraction column were higher than those with a C18 extraction column. This method was used to analyze the profiles of extracellular and intracellular BTX metabolites at different growth stages of K. brevis 165. This is the first time a Chinese strain of K. brevis has been reported that can produce toxic BTX metabolites. Five and eight kinds of BTX toxin metabolites were detected in the cell and culture media of K. brevis 165, respectively. Brevenal, a toxic BTX metabolite antagonist, was found for the first time in the culture media. The toxic BTX metabolites and brevenal in the K. brevis 165 cell and culture media were found to be fully proven in terms of the necessity of establishing a method for screening and identifying toxic BTX metabolites. The results found by qualitatively and quantitatively analyzing BTX metabolites produced by K. brevis 165 at different growth stages show that the total toxic BTX metabolite contents in single cells ranged between 6.78 and 21.53 pg/cell, and the total toxin concentration in culture media ranged between 10.27 and 449.11 μg/L. There were significant differences in the types and contents of toxic BTX metabolites with varying growth stages. Therefore, when harmful algal blooms occur, the accurate determination of BTX metabolite types and concentrations will be helpful to assess the ecological disaster risk in order to avoid hazards and provide appropriate disaster warnings.
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Affiliation(s)
- Huihui Shen
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiuxian Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- Correspondence:
| | - Yue Zhang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Peipei Zhang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Li
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Weijia Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiming Yu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
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Cunningham BR, Coleman RM, Schaefer AM, Hamelin EI, Johnson RC. Detection of Brevetoxin in Human Plasma by ELISA. J Anal Toxicol 2021; 46:322-327. [PMID: 33515246 PMCID: PMC8679180 DOI: 10.1093/jat/bkab010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 01/13/2021] [Accepted: 01/19/2021] [Indexed: 11/26/2022] Open
Abstract
Florida red tides have become more common and persistent in and around the Gulf of Mexico. When in bloom, red tides can produce brevetoxins in high concentrations, leading to human exposures primarily through contaminated food and ocean spray. The research described here includes adapting and validating a commercial brevetoxin water test kit for human plasma testing. Pooled plasma was fortified with a model brevetoxin, brevetoxin 3, at concentrations from 0.00500 to 3.00 ng/mL to generate calibration curves and quality control samples. The quantitative detection range was determined to be 0.0400–2.00 ng/mL brevetoxin 3 equivalents with inter- and intraday accuracies ranging from 94.0% to 109% and relative standard deviations <20%, which is within the US Food and Drug Administration guidelines for receptor-binding assays. Additionally, cross-reactivity was tested using 4 of the 10 known brevetoxins and 12 paralytic shellfish toxins. The cross-reactivity varied from 0.173% to 144% for the commercially available brevetoxin standards and 0% for the commercially available paralytic shellfish toxin standards. Fifty individual unexposed human plasma samples were measured to determine the limit of detection and endogenous interferences to the test. The validated method was used to test 31 plasma samples collected from humans potentially exposed to brevetoxins, detecting 11 positives. This method has been proven useful to measure human exposure to brevetoxins and can be applied to future exposure events.
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Affiliation(s)
- Brady R. Cunningham
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA
| | - Rebecca M. Coleman
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA
| | - Adam M. Schaefer
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Ft. Pierce, FL 34946, USA
| | - Elizabeth I. Hamelin
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA
- Author to whom correspondence should be addressed.
| | - Rudolph C. Johnson
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA
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Viallon J, Chinain M, Darius HT. Revisiting the Neuroblastoma Cell-Based Assay (CBA-N2a) for the Improved Detection of Marine Toxins Active on Voltage Gated Sodium Channels (VGSCs). Toxins (Basel) 2020; 12:E281. [PMID: 32349302 PMCID: PMC7290318 DOI: 10.3390/toxins12050281] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 02/06/2023] Open
Abstract
The neuroblastoma cell-based assay (CBA-N2a) is widely used for the detection of marine biotoxins in seafood products, yet a consensus protocol is still lacking. In this study, six key parameters of CBA-N2a were revisited: cell seeding densities, cell layer viability after 26 h growth, MTT incubation time, Ouabain and Veratridine treatment and solvent and matrix effects. A step-by-step protocol was defined identifying five viability controls for the validation of CBA-N2a results. Specific detection of two voltage gated sodium channel activators, pacific ciguatoxin (P-CTX3C) and brevetoxin (PbTx3) and two inhibitors, saxitoxin (STX) and decarbamoylsaxitoxin (dc-STX) was achieved, with EC50 values of 1.7 ± 0.35 pg/mL, 5.8 ± 0.9 ng/mL, 3 ± 0.5 ng/mL and 15.8 ± 3 ng/mL, respectively. When applied to the detection of ciguatoxin (CTX)-like toxicity in fish samples, limit of detection (LOD) and limit of quantification (LOQ) values were 0.031 ± 0.008 and 0.064 ± 0.016 ng P-CTX3C eq/g of flesh, respectively. Intra and inter-assays comparisons of viability controls, LOD, LOQ and toxicity in fish samples gave coefficients of variation (CVs) ranging from 3% to 29%. This improved test adaptable to either high throughput screening or composite toxicity estimation is a useful starting point for a standardization of the CBA-N2a in the field of marine toxin detection.
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Affiliation(s)
| | | | - Hélène Taiana Darius
- Institut Louis Malardé (ILM), Laboratory of Marine Biotoxins-UMR 241-EIO, 98713 Papeete-Tahiti, French Polynesia; (J.V.); (M.C.)
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Longo S, Sibat M, Viallon J, Darius HT, Hess P, Chinain M. Intraspecific Variability in the Toxin Production and Toxin Profiles of In Vitro Cultures of Gambierdiscus polynesiensis (Dinophyceae) from French Polynesia. Toxins (Basel) 2019; 11:toxins11120735. [PMID: 31861242 PMCID: PMC6950660 DOI: 10.3390/toxins11120735] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/11/2019] [Accepted: 12/12/2019] [Indexed: 12/14/2022] Open
Abstract
Ciguatera poisoning (CP) is a foodborne disease caused by the consumption of seafood contaminated with ciguatoxins (CTXs) produced by dinoflagellates in the genera Gambierdiscus and Fukuyoa. The toxin production and toxin profiles were explored in four clones of G. polynesiensis originating from different islands in French Polynesia with contrasted CP risk: RIK7 (Mangareva, Gambier), NHA4 (Nuku Hiva, Marquesas), RAI-1 (Raivavae, Australes), and RG92 (Rangiroa, Tuamotu). Productions of CTXs, maitotoxins (MTXs), and gambierone group analogs were examined at exponential and stationary growth phases using the neuroblastoma cell-based assay and liquid chromatography–tandem mass spectrometry. While none of the strains was found to produce known MTX compounds, all strains showed high overall P-CTX production ranging from 1.1 ± 0.1 to 4.6 ± 0.7 pg cell−1. In total, nine P-CTX analogs were detected, depending on strain and growth phase. The production of gambierone, as well as 44-methylgamberione, was also confirmed in G. polynesiensis. This study highlighted: (i) intraspecific variations in toxin production and profiles between clones from distinct geographic origins and (ii) the noticeable increase in toxin production of both CTXs, in particular CTX4A/B, and gambierone group analogs from the exponential to the stationary phase.
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Affiliation(s)
- Sébastien Longo
- Laboratoire de recherche sur les Biotoxines Marines Institut Louis Malardé-UMR 241 EIO, 98713 Papeete-Tahiti, French Polynesia; (J.V.); (H.T.D.); (M.C.)
- Correspondence:
| | - Manoella Sibat
- Laboratoire Phycotoxines, IFREMER, Rue de l’Ile d’Yeu, 44311 Nantes, France; (M.S.); (P.H.)
| | - Jérôme Viallon
- Laboratoire de recherche sur les Biotoxines Marines Institut Louis Malardé-UMR 241 EIO, 98713 Papeete-Tahiti, French Polynesia; (J.V.); (H.T.D.); (M.C.)
| | - Hélène Taiana Darius
- Laboratoire de recherche sur les Biotoxines Marines Institut Louis Malardé-UMR 241 EIO, 98713 Papeete-Tahiti, French Polynesia; (J.V.); (H.T.D.); (M.C.)
| | - Philipp Hess
- Laboratoire Phycotoxines, IFREMER, Rue de l’Ile d’Yeu, 44311 Nantes, France; (M.S.); (P.H.)
| | - Mireille Chinain
- Laboratoire de recherche sur les Biotoxines Marines Institut Louis Malardé-UMR 241 EIO, 98713 Papeete-Tahiti, French Polynesia; (J.V.); (H.T.D.); (M.C.)
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Role of Biomarkers in Monitoring Brevetoxins in Karenia brevis Exposed Shellfish. Food Saf (Tokyo) 2018; 6:33-43. [PMID: 32231945 DOI: 10.14252/foodsafetyfscj.2017021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 03/05/2018] [Indexed: 11/21/2022] Open
Abstract
Monitoring and management programs for marine toxins in seafood depend on efficient detection tools for their success in protecting public health. Here we review current methods of detection for neurotoxic shellfish poisoning (NSP) toxins, and current knowledge in brevetoxin metabolism in shellfish. In addition, we discuss a novel approach to developing monitoring tools for NSP toxins in molluscan shellfish. NSP is a seafood-borne disease caused by the consumption of brevetoxin-contaminated shellfish. Brevetoxins are a suite of cyclic polyether compounds found in blooms of the marine dinoflagellate Karenia brevis (K. brevis) and are potent neurotoxins. Preventive controls for NSP in the U.S. currently rely upon environmental monitoring of K. brevis blooms and assessment of their shellfish toxicity by mouse bioassay. The mouse bioassay for NSP approved by National Shellfish Sanitation Program was developed in the 1960s when very little information on the structural and toxicological properties of brevetoxins in algae and shellfish was available. Alternative methods to mouse bioassay based on current scientific knowledge in the area are needed for monitoring NSP toxins. It is now established that brevetoxins are metabolized extensively in shellfish. Algal brevetoxins undergo oxidation and reduction, as well as conjugation with fatty acids and amino acids in shellfish. Recently, three metabolites have been identified as biomarkers of brevetoxin exposure and toxicity in Eastern oyster (Crassostrea virginica) and hard clam (Mercenaria sp.). The role of these biomarkers in monitoring NSP toxins in K. brevis exposed molluscan shellfish is reviewed. Comparisons of biomarker levels by liquid chromatography-mass spectrometry (LC-MS) with composite toxin as measured by enzyme linked immunosorbent assay (ELISA), and shellfish toxicity by mouse bioassay, support the application of these biomarkers as a dynamic and powerful approach for monitoring brevetoxins in shellfish and prevention of NSP.
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Marine Toxins Analysis for Consumer Protection. RECENT ADVANCES IN THE ANALYSIS OF MARINE TOXINS 2017. [DOI: 10.1016/bs.coac.2017.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Turner AD, Higgins C, Davidson K, Veszelovszki A, Payne D, Hungerford J, Higman W. Potential threats posed by new or emerging marine biotoxins in UK waters and examination of detection methodology used in their control: brevetoxins. Mar Drugs 2015; 13:1224-54. [PMID: 25775421 PMCID: PMC4377981 DOI: 10.3390/md13031224] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/11/2015] [Accepted: 02/25/2015] [Indexed: 12/04/2022] Open
Abstract
Regular occurrence of brevetoxin-producing toxic phytoplankton in commercial shellfishery areas poses a significant risk to shellfish consumer health. Brevetoxins and their causative toxic phytoplankton are more limited in their global distribution than most marine toxins impacting commercial shellfisheries. On the other hand, trends in climate change could conceivably lead to increased risk posed by these toxins in UK waters. A request was made by UK food safety authorities to examine these toxins more closely to aid possible management strategies, should they pose a threat in the future. At the time of writing, brevetoxins have been detected in the Gulf of Mexico, the Southeast US coast and in New Zealand waters, where regulatory levels for brevetoxins in shellfish have existed for some time. This paper reviews evidence concerning the prevalence of brevetoxins and brevetoxin-producing phytoplankton in the UK, together with testing methodologies. Chemical, biological and biomolecular methods are reviewed, including recommendations for further work to enable effective testing. Although the focus here is on the UK, from a strategic standpoint many of the topics discussed will also be of interest in other parts of the world since new and emerging marine biotoxins are of global concern.
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Affiliation(s)
- Andrew D Turner
- Centre for Environment Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, UK.
| | - Cowan Higgins
- Agri-food and Biosciences Institute (AFBI), Newforge Lane, Belfast BT9 5PX, UK.
| | - Keith Davidson
- Scottish Association for Marine Science (SAMS), Oban, Argyll PA37 1QA, UK.
| | | | - Daniel Payne
- Centre for Environment Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, UK.
- University of Surrey, School of Biosciences and Medicine, Guildford, Surrey GU2 7TE, UK.
| | - James Hungerford
- United States Food and Drug Administration (USFDA), 22201 23rd Dr, S.E., Bothell, WA 98021, USA.
| | - Wendy Higman
- Centre for Environment Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, UK.
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Abraham A, El Said KR, Wang Y, Jester EL, Plakas SM, Flewelling LJ, Henry MS, Pierce RH. Biomarkers of brevetoxin exposure and composite toxin levels in hard clam (Mercenaria sp.) exposed to Karenia brevis blooms. Toxicon 2015; 96:82-8. [DOI: 10.1016/j.toxicon.2015.01.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 10/24/2022]
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Leighfield TA, Muha N, Ramsdell JS. Tissue distribution of amino acid- and lipid-brevetoxins after intravenous administration to C57BL/6 mice. Chem Res Toxicol 2014; 27:1166-75. [PMID: 24949875 DOI: 10.1021/tx500053f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Brevetoxins produced during algal blooms of the dinoflagellate Karenia are metabolized by shellfish into reduction, oxidation, and conjugation products. Brevetoxin metabolites comprising amino acid- and lipid conjugates account for a large proportion of the toxicity associated with the consumption of toxic shellfish. However, the disposition of these brevetoxin metabolites has not been established. Using intravenous exposure to C57BL/6 mice, we investigated the disposition in the body of three radiolabeled brevetoxin metabolites. Amino acid-brevetoxin conjugates represented by S-desoxy-BTX-B2 (cysteine-BTX-B) and lipid-brevetoxin conjugates represented by N-palmitoyl-S-desoxy-BTX-B2 were compared to dihydro-BTX-B. Tissue concentration profiles were unique to each of the brevetoxin metabolites tested, with dihydro-BTX-B being widely distributed to all tissues, S-desoxy-BTX-B2 concentrated in kidney, and N-palmitoyl-S-desoxy-BTX-B2 having the highest concentrations in spleen, liver, and lung. Elimination patterns were also unique: dihydro-BTX-B had a greater fecal versus urinary elimination, whereas urine was a more important elimination route for S-desoxy-BTX-B2, and N-palmitoyl-S-desoxy-BTX-B2 persisted in tissues and was eliminated equally in both urine and feces. The structures particular to each brevetoxin metabolite resulting from the reduction, amino acid conjugation, or fatty acid addition of BTX-B were likely responsible for these tissue-specific distributions and unique elimination patterns. These observed differences provide further insight into the contribution each brevetoxin metabolite class has to the observed potencies.
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Affiliation(s)
- Tod A Leighfield
- Marine Biotoxins Program, Center for Coastal Environmental Health and Biomolecular Research, NOAA-National Ocean Service , 219 Fort Johnson Road, Charleston, South Carolina 29412, United States
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Brevetoxin in blood, biological fluids, and tissues of sea turtles naturally exposed to Karenia brevis blooms in central west Florida. J Zoo Wildl Med 2013; 44:364-75. [PMID: 23805555 DOI: 10.1638/2012-0164r.1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In 2005 and 2006, the central west Florida coast experienced two intense Karenia brevis red tide events lasting from February 2005 through December 2005 and August 2006 through December 2006. Strandings of sea turtles were increased in the study area with 318 turtles (n = 174, 2005; n = 144, 2006) stranding between 1 January 2005 and 31 December 2006 compared to the 12-yr average of 43 +/- 23 turtles. Live turtles (n = 61) admitted for rehabilitation showed clinical signs including unresponsiveness, paresis, and circling. Testing of biological fluids and tissues for the presence of brevetoxin activity by enzyme-linked immunosorbent assay found toxin present in 93% (52 of 56) of live stranded sea turtles, and 98% (42 of 43) of dead stranded sea turtles tested. Serial plasma samples were taken from several live sea turtles during rehabilitation and toxin was cleared from the blood within 5-80 days postadmit depending upon the species tested. Among dead animals the highest brevetoxin levels were found in feces, stomach contents, and liver. The lack of significant pathological findings in the majority of animals necropsied supports toxin-related mortality.
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Leighfield TA, Muha N, Miles CO, Ramsdell JS. Semisynthesis of radiolabeled amino acid and lipid brevetoxin metabolites and their blood elimination kinetics in C57BL/6 mice. Chem Res Toxicol 2013; 26:868-77. [PMID: 23642029 DOI: 10.1021/tx4000057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Brevetoxin B (BTX-B), produced by dinoflagellates of the species Karenia, is a highly reactive molecule, due in part to an α,β-unsaturated aldehyde group at the terminal side chain, leading to the production of metabolites in shellfish by reduction, oxidation, and conjugation. We have investigated in mice the blood elimination of three common bioactive brevetoxin metabolites found in shellfish, which have been semisynthesized from BTX-B in radioactive forms. BTX-B was reduced at C42 to yield [(3)H] dihydro-BTX-B. [(3)H] S-desoxy-BTX-B2 (cysteine brevetoxin B) was semisynthesized from BTX-B by the conjugation of cysteine at the C50 olefinic group then [(3)H] radiolabeled by C42 aldehyde reduction. [(14)C] N-Palmitoyl-S-desoxy-BTX-B2 was prepared using S-desoxy-BTX-B2 as the starting material with addition of the [(14)C] radiolabeled fatty acid via cysteine-amide linkage. The elimination of intravenously administered [(3)H] S-desoxy-BTX-B2, [(14)C] N-palmitoyl-S-desoxy-BTX-B2, or [(3)H] dihydro-BTX-B was measured in blood collected from C57BL/6 mice over a 48 h period. Each brevetoxin metabolite tested exhibited biexponential elimination kinetics and fit a two-compartment model of elimination that was applied to generate toxicokinetic parameters. The rate of transfer between the central compartment (i.e., blood) and the peripheral compartment (e.g., tissue) for each brevetoxin differed substantially, with dihydro-BTX-B exchanging rapidly with the peripheral compartment, S-desoxy-BTX-B2 eliminating rapidly from the central compartment, and N-palmitoyl-S-desoxy-BTX-B2 eliminating slowly from the central compartment. Toxicokinetic parameters were analyzed in the context of the unique structure of each brevetoxin metabolite resulting from a reduction, amino acid conjugation, or fatty acid addition to BTX-B.
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Affiliation(s)
- Tod A Leighfield
- Marine Biotoxins Program, Center for Coastal Environmental Health and Biomolecular Research, NOAA-National Ocean Service, Charleston, South Carolina 29412, USA
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Echevarria M, Naar JP, Tomas C, Pawlik JR. Effects of Karenia brevis on clearance rates and bioaccumulation of brevetoxins in benthic suspension feeding invertebrates. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 106-107:85-94. [PMID: 22115907 DOI: 10.1016/j.aquatox.2011.10.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Revised: 10/19/2011] [Accepted: 10/21/2011] [Indexed: 05/31/2023]
Abstract
Blooms of the toxic alga Karenia brevis occur along coastlines where sessile suspension feeding invertebrates are common components of benthic communities. We studied the effects of K. brevis on four benthic suspension feeding invertebrates common to the coast of the SE United States: the sponge Haliclona tubifera, the bryozoan Bugula neritina, the bivalve Mercenaria mercenaria, and the tunicate Styela plicata. In controlled laboratory experiments, we determined the rate at which K. brevis was cleared from the seawater by these invertebrates, the effect of K. brevis on clearance rates of a non-toxic phytoplankton species, Rhodomonas sp., and the extent to which brevetoxins bioaccumulated in tissues of invertebrates using an enzyme-linked immunosorbent assay (ELISA). All four invertebrate species cleared significant quantities of K. brevis from seawater, with mean clearance rates ranging from 2.27 to 6.71 L g h⁻¹ for H. tubifera and S. plicata, respectively. In the presence of K. brevis, clearance rates of Rhodomonas sp. by B. neritina and S. plicata were depressed by 75% and 69%, respectively, while clearance rates by H. tubifera and M. mercenaria were unaffected. Negative effects of K. brevis were impermanent; after a recovery period of 13 h, B. neritina and S. plicata regained normal clearance rates. All four invertebrates accumulated high concentrations of brevetoxin after a 4h exposure to K. brevis, but when animals were transferred to filtered seawater for 15 h after exposure, brevetoxin concentrations in the tissues of H. tubifera and B. neritina decreased by ∼80%, while there was no change in toxin concentration in the tissues of S. plicata and M. mercenaria. High cell concentrations of K. brevis may cause a suppression of clearance rates in benthic suspension feeding invertebrates, resulting in a positive feedback for bloom formation. Also, high concentrations of toxin may accumulate in the tissues of benthic suspension feeding invertebrates that may be transferred to higher-level consumers.
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Affiliation(s)
- Michael Echevarria
- Center for Marine Science, University of North Carolina Wilmington, 5600 Marvin K. Moss Lane, Wilmington, NC 28409, USA.
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Bottein MYD, Kashinsky L, Wang Z, Littnan C, Ramsdell JS. Identification of ciguatoxins in Hawaiian monk seals Monachus schauinslandi from the Northwestern and Main Hawaiian Islands. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:5403-5409. [PMID: 21591690 DOI: 10.1021/es2002887] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Ciguatoxins are potent algal neurotoxins that concentrate in fish preyed upon by the critically endangered Hawaiian monk seal (Monachus schauinslandi). The only report for Hawaiian monk seal exposure to ciguatoxins occurred during a 1978 mortality event when two seal liver extracts tested positive by mouse bioassay. Ciguatoxins were thus proposed as a potential threat to the Hawaiian monk seal population. To reinvestigate monk seal exposure to ciguatoxins we utilized more selective detection methods, the Neuro-2A cytotoxicity assay, to quantify ciguatoxin activity and an analytical method LC-MS/MS to confirm the molecular structure. Tissue analysis from dead stranded animals revealed ciguatoxin activity in brain, liver, and muscle, whereas analysis of blood samples from 55 free-ranging animals revealed detectable levels of ciguatoxin activity (0.43 to 5.49 pg/mL P-CTX-1 equiv) in 19% of the animals. Bioassay-guided LC fractionation of two monk seal liver extracts identified several ciguatoxin-like peaks of activity including a peak corresponding to the P-CTX-3C which was confirmed present by LC-MS/MS. In conclusion, this work provides first confirmation that Hawaiian monk seals are exposed to significant levels of ciguatoxins and first evidence of transfer of ciguatoxin to marine mammals. This threat could pose management challenges for this endangered marine mammal species.
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Affiliation(s)
- Marie-Yasmine Dechraoui Bottein
- Marine Biotoxins Program, Center for Coastal Environmental Health and Biomolecular Research, NOAA-National Ocean Service, Charleston, South Carolina 29412, United States
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Toxicokinetics of the ciguatoxin P-CTX-1 in rats after intraperitoneal or oral administration. Toxicology 2011; 284:1-6. [DOI: 10.1016/j.tox.2011.02.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 02/08/2011] [Accepted: 02/15/2011] [Indexed: 11/20/2022]
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Wang Z, Ramsdell JS. Analysis of interactions of brevetoxin-B and human serum albumin by liquid chromatography/mass spectrometry. Chem Res Toxicol 2010; 24:54-64. [PMID: 21142195 DOI: 10.1021/tx1002854] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Brevetoxins are neurotoxins produced by marine dinoflagellates, primarily Karenia brevis, and can cause intoxication and even mortality of marine species, affect human health through the consumption of brevetoxin-contaminated shellfish, and effect respiratory irritation through aerosol exposure at coastal areas. Brevetoxin-A and brevetoxin-B, the major brevetoxins produced in algae, are metabolized to a series of amino acid and peptide-related derivatives in shellfish through the reactions of the amino acid residue cysteine with an α,β-unsaturated aldehyde group. In this paper, covalent interactions between brevetoxin and proteins were investigated using brevetoxin-B and human serum albumin (HSA) as a model. It is demonstrated that both noncovalent and covalent interactions can occur between brevetoxin-B and HSA with in vitro experiments. Covalent adducts of brevetoxin-B and HSA were generated under physiological conditions and reduced with sodium borohydride based on the reaction conditions of single amino acid residues with brevetoxin-B. LC/MS analysis of toxin-treated HSA recognized the formation of the intact protein adducts with primarily one and two toxin molecules attached to one HSA molecule. HSA treated with/without brevetoxin-B was digested with trypsin, trypsin following chymotrypsin, and Pronase, respectively, for LC/MS analysis of adduction sites. Brevetoxin-B was found to react primarily with Cys(34) and His(3) and with His and Lys at other sites of HSA with variable reactivity and with Lys in general the least reactive.
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Affiliation(s)
- Zhihong Wang
- Marine Biotoxins Program, Center for Coastal Environmental Health and Biomolecular Research, NOAA/National Ocean Service, 219 Fort Johnson Road, Charleston, South Carolina 29412, USA
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Bottein MYD, Fuquay JM, Munday R, Selwood AI, van Ginkel R, Miles CO, Loader JI, Wilkins AL, Ramsdell JS. Bioassay methods for detection of N-palmitoylbrevetoxin-B2 (BTX-B4). Toxicon 2010; 55:497-506. [DOI: 10.1016/j.toxicon.2009.09.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2009] [Revised: 09/23/2009] [Accepted: 09/30/2009] [Indexed: 11/26/2022]
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Advances in monitoring and toxicity assessment of brevetoxins in molluscan shellfish. Toxicon 2009; 56:137-49. [PMID: 19925816 DOI: 10.1016/j.toxicon.2009.11.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 10/07/2009] [Accepted: 11/09/2009] [Indexed: 11/20/2022]
Abstract
Herein, we describe advancements in monitoring of brevetoxins in molluscan shellfish, with respect to exposure management and control of neurotoxic shellfish poisoning (NSP). Current knowledge of the fate of brevetoxins in molluscan shellfish, and the toxic potency of brevetoxin metabolites, is presented. We review rapid assays for measuring composite brevetoxins, and methodology for measuring constituent brevetoxins, in contaminated shellfish. The applicability of in vitro methods for estimating brevetoxin burden and composite toxicity in shellfish is assessed. Specific and measurable biomarkers of brevetoxin exposure and toxicity in shellfish, and of human intoxication, are described. Their utility in regulatory monitoring of toxic shellfish and in clinical diagnosis of NSP is evaluated.
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Plakas SM, Jester ELE, El Said KR, Granade HR, Abraham A, Dickey RW, Scott PS, Flewelling LJ, Henry M, Blum P, Pierce R. Monitoring of brevetoxins in the Karenia brevis bloom-exposed Eastern oyster (Crassostrea virginica). Toxicon 2008; 52:32-8. [PMID: 18582486 DOI: 10.1016/j.toxicon.2008.04.174] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 04/29/2008] [Accepted: 04/30/2008] [Indexed: 10/22/2022]
Abstract
Brevetoxin uptake and elimination were examined in Eastern oyster (Crassostrea virginica) exposed to recurring blooms of the marine alga Karenia brevis in Sarasota Bay, FL, over a three-year period. Brevetoxins were monitored by in vitro assays (ELISA, cytotoxicity assay, and receptor binding assay) and LC-MS, with in vivo toxicity of shellfish extracts assessed by the traditional mouse bioassay. Measurements by all methods reflected well the progression and magnitude of the blooms. Highest levels recorded by mouse bioassay at bloom peak were 157 MU/100g. Oysters were toxic by mouse bioassay at levels >or=20 MU/100g for up to two weeks after bloom dissipation, whereas brevetoxins were measurable by in vitro assays and LC-MS for several months afterwards. For the structure-based methods, summed values for the principal brevetoxin metabolites of PbTx-2 (cysteine and cysteine sulfoxide conjugates), as determined by LC-MS, were highly correlated (r(2)=0.90) with composite toxin measurements by ELISA. ELISA and LC-MS values also correlated well (r(2)=0.74 and 0.73, respectively) with those of mouse bioassay. Pharmacology-based cytotoxicity and receptor binding assays did not correlate as well (r(2)=0.65), and were weakly correlated with mouse bioassay (r(2)=0.48 and 0.50, respectively). ELISA and LC-MS methods offer rapid screening and confirmation, respectively, of brevetoxin contamination in the oyster, and are excellent alternatives to mouse bioassay for assessing oyster toxicity following K. brevis blooms.
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Affiliation(s)
- Steven M Plakas
- Gulf Coast Seafood Laboratory, U.S. Food and Drug Administration, 1 Iberville Drive, Dauphin Island, AL 36528, USA.
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Selwood AI, Ginkel RV, Wilkins AL, Munday R, Ramsdell JS, Jensen DJ, Cooney JM, Miles CO. Semisynthesis of S-desoxybrevetoxin-B2 and brevetoxin-B2, and assessment of their acute toxicities. Chem Res Toxicol 2008; 21:944-50. [PMID: 18335998 DOI: 10.1021/tx700441w] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Brevetoxins are neurotoxins associated with blooms of marine algae such as Karenia brevis and can accumulate in the marine food chain, causing intoxication of marine animals and people consuming seafood. Brevetoxin-B2 ( 5) is a toxic metabolite produced in shellfish exposed to algae that contain brevetoxin-B ( 1). S-Desoxybrevetoxin-B2 ( 4) has been proposed as a cometabolite produced during this transformation, and while LC-MS analyses suggest its presence in shellfish, it has not yet been isolated and characterized. Studies on these materials are severely constrained by the difficulty of obtaining and purifying them from natural sources. We have developed a convenient one-pot conversion of commercially available brevetoxin-B ( 1) into S-desoxybrevetoxin-B2 ( 4), and a simple method for converting 4 into brevetoxin-B2 ( 5). Full NMR and mass-spectral characterization of 4 and 5 confirmed their structures and showed that the ratio of diastereoisomers in the synthetic 4 and 5 was similar to that observed in naturally contaminated shellfish. The LD 50 values for 4, 5, and dihydrobrevetoxin-B ( 6) by ip injection in mice were 211, 400, and 250 microg/kg, respectively. The methodology for synthesis of brevetoxin metabolites should greatly facilitate toxicological, biochemical and immunochemical studies of these substances, as well as the production of analytical standards.
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