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Nederlof RA, van der Veen D, Perrault JR, Bast R, Barron HW, Bakker J. Emerging Insights into Brevetoxicosis in Sea Turtles. Animals (Basel) 2024; 14:991. [PMID: 38612230 PMCID: PMC11010821 DOI: 10.3390/ani14070991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/14/2024] Open
Abstract
This review summarizes the current understanding of how brevetoxins, produced by Karenia brevis during harmful algal blooms, impact sea turtle health. Sea turtles may be exposed to brevetoxins through ingestion, inhalation, maternal transfer, and potentially absorption through the skin. Brevetoxins bind to voltage-gated sodium channels in the central nervous system, disrupting cellular function and inducing neurological symptoms in affected sea turtles. Moreover, the current evidence suggests a broader and longer-term impact on sea turtle health beyond what is seen during stranding events. Diagnosis relies on the detection of brevetoxins in tissues and plasma from stranded turtles. The current treatment of choice, intravenous lipid emulsion therapy, may rapidly reduce symptoms and brevetoxin concentrations, improving survival rates. Monitoring, prevention, and control strategies for harmful algal blooms are discussed. However, as the frequency and severity of blooms are expected to increase due to climate change and increased environmental pollution, continued research is needed to better understand the sublethal effects of brevetoxins on sea turtles and the impact on hatchlings, as well as the pharmacokinetic mechanisms underlying brevetoxicosis. Moreover, research into the optimization of treatments may help to protect endangered sea turtle populations in the face of this growing threat.
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Affiliation(s)
| | | | - Justin R. Perrault
- Loggerhead Marinelife Center, Juno Beach, FL 33408, USA; (J.R.P.); (H.W.B.)
| | - Robin Bast
- Clinic for the Rehabilitation of Wildlife, Inc., Sanibel, FL 33957, USA;
| | - Heather W. Barron
- Loggerhead Marinelife Center, Juno Beach, FL 33408, USA; (J.R.P.); (H.W.B.)
| | - Jaco Bakker
- Animal Science Department, Biomedical Primate Research Centre, Lange Kleiweg 161, 2288 GJ Rijswijk, The Netherlands;
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2
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Indicators of oxidative stress in leukocytes isolated from bottlenose dolphins (Tursiops truncatus) in response to a proinflammatory challenge. Microb Pathog 2022; 173:105800. [DOI: 10.1016/j.micpath.2022.105800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 09/20/2022] [Accepted: 09/21/2022] [Indexed: 11/06/2022]
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Annunziato M, Eeza MNH, Bashirova N, Lawson A, Matysik J, Benetti D, Grosell M, Stieglitz JD, Alia A, Berry JP. An integrated systems-level model of the toxicity of brevetoxin based on high-resolution magic-angle spinning nuclear magnetic resonance (HRMAS NMR) metabolic profiling of zebrafish embryos. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 803:149858. [PMID: 34482148 DOI: 10.1016/j.scitotenv.2021.149858] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/18/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Brevetoxins (PbTx) are a well-recognized group of neurotoxins associated with harmful algal blooms, and specifically recurrent "Florida Red Tides," in marine waters that are linked to impacts on both human and ecosystem health including well-documented "fish kills" and marine mammal mortalities in affected coastal waters. Understanding mechanisms and pathways of PbTx toxicity enables identification of relevant biomarkers to better understand these environmental impacts, and improve monitoring efforts, in relation to this toxin. Toward a systems-level understanding of toxicity, and identification of potential biomarkers, high-resolution magic angle spinning nuclear magnetic resonance (HRMAS NMR) was utilized for metabolic profiling of zebrafish (Danio rerio) embryos, as an established toxicological model, exposed to PbTx-2 (the most common congener in marine waters). Metabolomics studies were, furthermore, complemented by an assessment of the toxicity of PbTx-2 in embryonic stages of zebrafish and mahi-mahi (Coryphaena hippurus), the latter representing an ecologically and geographically relevant marine species of fish, which identified acute embryotoxicity at environmentally relevant (i.e., parts-per-billion) concentrations in both species. HRMAS NMR analysis of intact zebrafish embryos exposed to sub-lethal concentrations of PbTx-2 afforded well-resolved spectra, and in turn, identification of 38 metabolites of which 28 were found to be significantly altered, relative to controls. Metabolites altered by PbTx-2 exposure specifically included those associated with (1) neuronal excitotoxicity, as well as associated neural homeostasis, and (2) interrelated pathways of carbohydrate and energy metabolism. Metabolomics studies, thereby, enabled a systems-level model of PbTx toxicity which integrated multiple metabolic, molecular and cellular pathways, in relation to environmentally relevant concentrations of the toxin, providing insight to not only targets and mechanisms, but potential biomarkers pertinent to environmental risk assessment and monitoring strategies.
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Affiliation(s)
- Mark Annunziato
- Institute of Environment, Department of Chemistry and Biochemistry, Florida International University, 3000 NE 151st Street, North Miami, FL 33181, USA
| | - Muhamed N H Eeza
- Institute of Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany; Institute for Analytical Chemistry, University of Leipzig, Leipzig, Germany
| | - Narmin Bashirova
- Institute of Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany; Institute for Analytical Chemistry, University of Leipzig, Leipzig, Germany
| | - Ariel Lawson
- Institute of Environment, Department of Chemistry and Biochemistry, Florida International University, 3000 NE 151st Street, North Miami, FL 33181, USA
| | - Jörg Matysik
- Institute for Analytical Chemistry, University of Leipzig, Leipzig, Germany
| | - Daniel Benetti
- Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, FL, USA
| | - Martin Grosell
- Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, FL, USA
| | - John D Stieglitz
- Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, FL, USA
| | - A Alia
- Institute of Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany; Leiden Institute of Chemistry, Leiden University, 2333 Leiden, the Netherlands.
| | - John P Berry
- Institute of Environment, Department of Chemistry and Biochemistry, Florida International University, 3000 NE 151st Street, North Miami, FL 33181, USA; Biomolecular Science Institute, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA.
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4
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Isolation, characterization, and ecotoxicological application of marine mammal skin fibroblast cultures. In Vitro Cell Dev Biol Anim 2020; 56:744-759. [PMID: 33078324 DOI: 10.1007/s11626-020-00506-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 09/07/2020] [Indexed: 10/23/2022]
Abstract
Marine mammal cell cultures are a multifunctional instrument for acquiring knowledge about life in the world's oceans in physiological, biochemical, genetic, and ecotoxicological aspects. We succeeded in isolation, cultivation, and characterization of skin fibroblast cultures from five marine mammal species. The cells of the spotted seal (Phoca largha), the sea lion (Eumetopias jubatus), and the walrus (Odobenus rosmarus) are unpretentious to the isolation procedure. The sea otter (Enhydra lutris) fibroblasts should be isolated by trypsin disaggregation, while only mechanical disaggregation was suitable for the beluga whale (Delphinapterus leucas) cells. The cell growth parameters have been determined allowing us to find the optimal seeding density for continuous and effective cultivation. The effects of nonpathogenic algal extracts on proliferation, viability, and functional activity of marine mammal cells in vitro have been presented and discussed for the first time.
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Levin M, Jasperse L, Gebhard E, Rousselet E, Walsh C. Lack of cross-reactivity of human and porcine reagents to quantify manatee (Trichechus manatus) cytokines. Vet Immunol Immunopathol 2018; 203:57-59. [PMID: 30243374 DOI: 10.1016/j.vetimm.2018.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 07/26/2018] [Accepted: 07/29/2018] [Indexed: 11/28/2022]
Abstract
Veterinary medical examinations, including both physical examination and diagnostic tests, are important to monitor the health of both managed-care and wild marine mammals. However, limited species-specific reagents and assays are available that may contribute to a broader medical examination. This project evaluated if commercially available human and porcine antibodies and reagents would cross-react with manatee (Trichechus manatus) cytokines as the first step to validate a new diagnostic tool for manatees. Overall, as a result of limited cross-reactivity, human and porcine commercial reagents did not allow for the quantification of manatee cytokines. At this point, caution must be exercised when using human or porcine immunoassay reagents to quantify manatee cytokines if the reagents have not been fully validated. Future efforts will continue to explore and test the cross-reactivity of reagents to measure manatee cytokines as new species-specific and commercial reagents become available.
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Affiliation(s)
- Milton Levin
- Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Road, Unit 3089, Storrs, CT, 06269, United States.
| | - Lindsay Jasperse
- Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Road, Unit 3089, Storrs, CT, 06269, United States
| | - Erika Gebhard
- Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Road, Unit 3089, Storrs, CT, 06269, United States
| | - Estelle Rousselet
- Aquatic Animal Health Program, Department of Large Animal Clinical Sciences, College of Veterinary Medicine University of Florida, 2015 SW 16th Avenue, Gainesville, FL, 32608, United States
| | - Catherine Walsh
- Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL, 34236, United States
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Perrault JR, Stacy NI, Lehner AF, Mott CR, Hirsch S, Gorham JC, Buchweitz JP, Bresette MJ, Walsh CJ. Potential effects of brevetoxins and toxic elements on various health variables in Kemp's ridley (Lepidochelys kempii) and green (Chelonia mydas) sea turtles after a red tide bloom event. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 605-606:967-979. [PMID: 28693110 DOI: 10.1016/j.scitotenv.2017.06.149] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/18/2017] [Accepted: 06/19/2017] [Indexed: 06/07/2023]
Abstract
Natural biotoxins and anthropogenic toxicants pose a significant risk to sea turtle health. Documented effects of contaminants include potential disease progression and adverse impacts on development, immune function, and survival in these imperiled species. The shallow seagrass habitats of Florida's northwest coast (Big Bend) serve as an important developmental habitat for Kemp's ridley (Lepidochelys kempii) and green (Chelonia mydas) sea turtles; however, few studies have been conducted in this area. Our objectives were (1) to evaluate plasma analytes (mass, minimum straight carapace length, body condition index [BCI], fibropapilloma tumor score, lysozyme, superoxide dismutase, reactive oxygen/nitrogen species, plasma protein electrophoresis, cholesterol, and total solids) in Kemp's ridleys and green turtles and their correlation to brevetoxins that were released from a red tide bloom event from July-October 2014 in the Gulf of Mexico near Florida's Big Bend, and (2) to analyze red blood cells in Kemp's ridleys and green turtles for toxic elements (arsenic, cadmium, lead, mercury, selenium, thallium) with correlation to the measured plasma analytes. Positive correlations were observed between brevetoxins and α2-globulins in Kemp's ridleys and α2- and γ-globulins in green turtles, indicating potential immunostimulation. Arsenic, cadmium, and lead positively correlated with superoxide dismutase in Kemp's ridleys, suggesting oxidative stress. Lead and mercury in green turtles negatively correlated with BCI, while mercury positively correlated with total tumor score of green turtles afflicted with fibropapillomatosis, suggesting a possible association with mercury and increased tumor growth. The total tumor score of green turtles positively correlated with total protein, total globulins, α2-globulins, and γ-globulins, further suggesting inflammation and immunomodulation as a result of fibropapillomatosis. Lastly, brevetoxin concentrations were positively related to tumor score, indicating potential tumor promotion by brevetoxin. These results signify that brevetoxins and toxic elements elicit various negative effects on sea turtle health, including immune function, oxidative stress, and possibly disease progression.
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Affiliation(s)
- Justin R Perrault
- Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA.
| | - Nicole I Stacy
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, 2015 Southwest 16th Avenue, PO Box 100136, Gainesville, FL 32610, USA
| | - Andreas F Lehner
- Michigan State University Veterinary Diagnostic Laboratory, 4125 Beaumont Road, Lansing, MI 48910, USA
| | - Cody R Mott
- Inwater Research Group, 4160 Northeast Hyline Drive, Jensen Beach, FL 34957, USA
| | - Sarah Hirsch
- Loggerhead Marinelife Center, 14200 U.S. Highway 1, Juno Beach, FL 33408, USA
| | - Jonathan C Gorham
- Inwater Research Group, 4160 Northeast Hyline Drive, Jensen Beach, FL 34957, USA
| | - John P Buchweitz
- Michigan State University Veterinary Diagnostic Laboratory, 4125 Beaumont Road, Lansing, MI 48910, USA
| | - Michael J Bresette
- Inwater Research Group, 4160 Northeast Hyline Drive, Jensen Beach, FL 34957, USA
| | - Catherine J Walsh
- Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA
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7
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Boroda AV. Marine mammal cell cultures: To obtain, to apply, and to preserve. MARINE ENVIRONMENTAL RESEARCH 2017; 129:316-328. [PMID: 28683932 DOI: 10.1016/j.marenvres.2017.06.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/28/2017] [Accepted: 06/28/2017] [Indexed: 06/07/2023]
Abstract
The world's oceans today have become a place for the disposal of toxic waste, which leads to the degradation of marine mammal habitats and populations. Marine mammal cell cultures have proven to be a multifunctional tool for studying the peculiarities of the cell physiology and biochemistry of these animals as well as the destructive effects of anthropogenic and natural toxicants. This review describes the sources of marine mammal live tissues and the methods required for establishing cell cultures, their use, and long-term storage. Approaches to conserving rare animal species by applying cell biology methodologies are also discussed.
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Affiliation(s)
- A V Boroda
- A.V. Zhirmunsky Institute of Marine Biology, National Scientific Center of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences, 17 Palchevsky St., Vladivostok, 690041, Russia.
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Chen W, Tuladhar A, Rolle S, Lai Y, Rodriguez Del Rey F, Zavala CE, Liu Y, Rein KS. Brevetoxin-2, is a unique inhibitor of the C-terminal redox center of mammalian thioredoxin reductase-1. Toxicol Appl Pharmacol 2017; 329:58-66. [PMID: 28551108 DOI: 10.1016/j.taap.2017.05.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/15/2017] [Accepted: 05/22/2017] [Indexed: 11/15/2022]
Abstract
Karenia brevis, the Florida red tide dinoflagellate produces a suite of neurotoxins known as the brevetoxins. The most abundant of the brevetoxins PbTx-2, was found to inhibit the thioredoxin-thioredoxin reductase system, whereas the PbTx-3 has no effect on this system. On the other hand, PbTx-2 activates the reduction of small disulfides such as 5,5'-dithio-bis-(2-nitrobenzoic acid) by thioredoxin reductase. PbTx-2 has an α, β-unsaturated aldehyde moiety which functions as an efficient electrophile and selenocysteine conjugates are readily formed. PbTx-2 blocks the inhibition of TrxR by the inhibitor curcumin, whereas curcumin blocks PbTx-2 activation of TrxR. It is proposed that the mechanism of inhibition of thioredoxin reduction is via the formation of a Michael adduct between selenocysteine and the α, β-unsaturated aldehyde moiety of PbTx-2. PbTx-2 had no effect on the rates of reactions catalyzed by related enzymes such as glutathione reductase, glutathione peroxidase or glutaredoxin.
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Affiliation(s)
- Wei Chen
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Anupama Tuladhar
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Shantelle Rolle
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Yanhao Lai
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Freddy Rodriguez Del Rey
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Cristian E Zavala
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Yuan Liu
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States; Biomolecular Sciences Institute, School of Integrated Sciences and Humanity, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Kathleen S Rein
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States.
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9
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Walsh CJ, Butawan M, Yordy J, Ball R, Flewelling L, de Wit M, Bonde RK. Sublethal red tide toxin exposure in free-ranging manatees (Trichechus manatus) affects the immune system through reduced lymphocyte proliferation responses, inflammation, and oxidative stress. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 161:73-84. [PMID: 25678466 DOI: 10.1016/j.aquatox.2015.01.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 06/04/2023]
Abstract
The health of many Florida manatees (Trichechus manatus latirostris) is adversely affected by exposure to blooms of the toxic dinoflagellate, Karenia brevis. K. brevis blooms are common in manatee habitats of Florida's southwestern coast and produce a group of cyclic polyether toxins collectively referred to as red tide toxins, or brevetoxins. Although a large number of manatees exposed to significant levels of red tide toxins die, several manatees are rescued from sublethal exposure and are successfully treated and returned to the wild. Sublethal brevetoxin exposure may potentially impact the manatee immune system. Lymphocyte proliferative responses and a suite of immune function parameters in the plasma were used to evaluate effects of brevetoxin exposure on health of manatees rescued from natural exposure to red tide toxins in their habitat. Blood samples were collected from rescued manatees at Lowry Park Zoo in Tampa, FL and from healthy, unexposed manatees in Crystal River, FL. Peripheral blood leukocytes (PBL) isolated from whole blood were stimulated with T-cell mitogens, ConA and PHA. A suite of plasma parameters, including plasma protein electrophoresis profiles, lysozyme activity, superoxide dismutase (SOD) activity, and reactive oxygen/nitrogen (ROS/RNS) species, was also used to assess manatee health. Significant decreases (p<0.05) in lymphocyte proliferation were observed in ConA and PHA stimulated lymphocytes from rescued animals compared to non-exposed animals. Significant correlations were observed between oxidative stress markers (SOD, ROS/RNS) and plasma brevetoxin concentrations. Sublethal exposure to brevetoxins in the wild impacts some immune function components, and thus, overall health, in the Florida manatee.
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Affiliation(s)
- Catherine J Walsh
- Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA.
| | - Matthew Butawan
- Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA.
| | - Jennifer Yordy
- Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA.
| | - Ray Ball
- Lowry Park Zoo, 1101 W Sligh Ave, Tampa, FL 33604, USA.
| | - Leanne Flewelling
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, 100 8th Ave SE, St. Petersburg, FL 33701, USA.
| | - Martine de Wit
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, 100 8th Ave SE, St. Petersburg, FL 33701, USA.
| | - Robert K Bonde
- U.S. Geological Survey, Sirenia Project, 7920 NE 71st Street, Gainesville, FL 32653, USA.
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Castelblanco-Martínez DN, Nourisson C, Quintana-Rizzo E, Padilla-Saldivar J, Schmitter-Soto JJ. Potential effects of human pressure and habitat fragmentation on population viability of the Antillean manatee Trichechus manatus manatus: a predictive model. ENDANGER SPECIES RES 2012. [DOI: 10.3354/esr00439] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Wetzel DL, Reynolds JE, Sprinkel JM, Schwacke L, Mercurio P, Rommel SA. Fatty acid profiles as a potential lipidomic biomarker of exposure to brevetoxin for endangered Florida manatees (Trichechus manatus latirostris). THE SCIENCE OF THE TOTAL ENVIRONMENT 2010; 408:6124-6133. [PMID: 20880571 DOI: 10.1016/j.scitotenv.2010.08.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 08/25/2010] [Accepted: 08/26/2010] [Indexed: 05/29/2023]
Abstract
Fatty acid signature analysis (FASA) is an important tool by which marine mammal scientists gain insight into foraging ecology. Fatty acid profiles (resulting from FASA) represent a potential biomarker to assess exposure to natural and anthropogenic stressors. Florida manatees are well studied, and an excellent necropsy program provides a basis against which to assess this budding tool. Results using samples from 54 manatees assigned to four cause-of-death categories indicated that those animals exposed to or that died due to brevetoxin exposure (red tide, or RT samples) demonstrate a distinctive hepatic fatty acid profile. Discriminant function analysis indicated that hepatic fatty acids could be used to classify RT versus non-RT liver samples with reasonable certainty. A discriminant function was derived based on 8 fatty acids which correctly classified 100% of samples from a training dataset (10 RT and 25 non-RT) and 85% of samples in a cross-validation dataset (5 RT and 13 non-RT). Of the latter dataset, all RT samples were correctly classified, but two of thirteen non-RT samples were incorrectly classified. However, the "incorrect" samples came from manatees that died due to other causes during documented red tide outbreaks; thus although the proximal cause of death was due to watercraft collisions, exposure to brevetoxin may have affected these individuals in ways that increased their vulnerability. This use of FASA could: a) provide an additional forensic tool to help scientists and managers to understand cause of death or debilitation due to exposure to red tide in manatees; b) serve as a model that could be applied to studies to improve assessments of cause of death in other marine mammals; and c) be used, as in humans, to help diagnose metabolic disorders or disease states in manatees and other species.
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Affiliation(s)
- Dana L Wetzel
- Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, United States.
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Walsh CJ, Leggett SR, Carter BJ, Colle C. Effects of brevetoxin exposure on the immune system of loggerhead sea turtles. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 97:293-303. [PMID: 20060602 DOI: 10.1016/j.aquatox.2009.12.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 12/04/2009] [Accepted: 12/12/2009] [Indexed: 05/28/2023]
Abstract
Blooms of the toxic dinoflagellate, Karenia brevis, occur almost annually off the Florida coast. These blooms, commonly called "red tides", produce a group of neurotoxins collectively termed brevetoxins. Many species of sealife, including sea turtles, are severely impacted by brevetoxin exposure. Effects of brevetoxins on immune cells were investigated in rescued loggerhead sea turtles, Caretta caretta, as well as through in vitro experiments using peripheral blood leukocytes (PBL) collected from captive sea turtles. In rescued animals, plasma brevetoxin concentrations were measured using a competitive ELISA. Plasma lysozyme activity was measured using a turbidity assay. Lysozyme activity correlated positively with plasma brevetoxin concentrations. Differential expression of genes affected by brevetoxin exposure was determined using two separate suppression subtractive hybridization experiments. In one experiment, genes from PBL collected from sea turtles rescued from red tide toxin exposure were compared to genes from PBL collected from healthy captive loggerhead sea turtles. In the second experiment, PBL from healthy captive loggerhead sea turtles were exposed to brevetoxin (500 ng PbTx-2/ml) in vitro for 18 h and compared to unexposed PBL. Results from the subtraction hybridization experiment conducted with red tide rescued sea turtle PBL indicated that genes involved in oxidative stress or xenobiotic metabolism were up-regulated. Using quantitative real-time PCR, a greater than 2-fold increase in superoxide dismutase and thioredoxin and greater than 10-fold increase in expression of thiopurine S-methyltransferase were observed. Results from the in vitro subtraction hybridization experiment indicated that genes coding for cytochrome c oxidases were the major up-regulated genes. Using quantitative real-time PCR, a greater than 8-fold increase in expression of beta-tubulin and greater than 3-fold increase in expression of ubiquinol were observed. Brevetoxin exposure may have significant implications for immune function in loggerhead sea turtles.
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Affiliation(s)
- Catherine J Walsh
- Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA.
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Cellular metabolism of brevetoxin (PbTx-2) by a monocyte cell line (U-937). Toxicon 2008; 53:135-45. [PMID: 19027773 DOI: 10.1016/j.toxicon.2008.10.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 10/23/2008] [Accepted: 10/24/2008] [Indexed: 11/23/2022]
Abstract
Blooms of Karenia brevis produce brevetoxins which cause neurotoxic shellfish poisoning and respiratory symptoms in humans as well as harmful effects on sea life. To investigate potential effects of brevetoxins on immune system components, a monocyte cell line (U-937) was exposed in vitro to PbTx-2. U-937 cells metabolized PbTx-2 through cellular detoxification mechanisms, as evidenced by depletion of intracellular glutathione and formation of glutathione and cysteine conjugates. Total intracellular glutathione was significantly decreased in toxin-treated cells compared to control cells, as measured using an enzymatic recycling method. LC/MS was used to detect the following brevetoxin metabolites: a cysteine-PbTx-2 conjugate (m/z 1018) and two putative glutathione-PbTx-2 conjugates (m/z 1204 and 1222). During 3h incubation, glutathione conjugates were detectable as early as 1h and increased in concentration after 2 and 3h. A cysteine-PbTx-2 conjugate appeared after 2h and increased in concentration after 3h. Detectable levels of brevetoxin conjugates were present in response to toxin concentrations of 1muM. Depletion of intracellular glutathione and formation of brevetoxin metabolites, with changes in concentrations over time, suggest immune cells (U-937) have important cellular detoxification pathways for PbTx-2.
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