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Topal A, Oğuş H, Sulukan E, Comaklı S, Ceyhun SB. Okadaic acid enhances NfKB, TLR-4, caspase 3, ERK ½, c-FOS, and 8-OHdG signaling pathways activation in brain tissues of zebrafish larvae. FISH & SHELLFISH IMMUNOLOGY 2024; 149:109529. [PMID: 38561069 DOI: 10.1016/j.fsi.2024.109529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/20/2024] [Accepted: 03/27/2024] [Indexed: 04/04/2024]
Abstract
This study was designed to investigate the potential neuronal damage mechanism of the okadaic acid (OA) in the brain tissues of zebrafish embryos by evaluating in terms of immunofluorescence of Nf KB, TLR-4, caspase 3, ERK ½, c-FOS and 8-OHdG signaling pathways. We also evaluated body malformations. For this purpose, zebrafish embryos were exposed to 0.5 μg/ml, 1 μg/ml and 2.5 μg/ml of OA for 5 days. After application, FITC/GFP labeled protein-specific antibodies were used in immunofluorescence assay for NfKB, TLR-4, caspase 3, ERK ½, c-FOS and 8-OHdG respectively. The results indicated that OA caused immunofluorescence positivity of NfKB, TLR-4, caspase 3, ERK ½, c-FOS and 8-OHdG in a dose-dependent manner in the brain tissues of zebrafish embryos. Pericardial edema (PE), nutrient sac edema (YSE) and body malformations, tail malformation, short tail and head malformation (BM) were detected in zebrafish embryos. These results suggest that OA induces neuronal damage by affecting the modulation of DNA damage, apoptotic, and inflammatory activities in the brain tissues of zebrafish embryos. The increase in signaling pathways shows that OA can cause damage in the structure and function of brain nerve cells. Our results provide a new basis for the comprehensive assessment of the neural damage of OA and will offer enable us to better understand molecular the mechanisms underlying the pathophysiology of OA toxicity.
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Affiliation(s)
- Ahmet Topal
- Department of Basic Sciences, Faculty of Fisheries, Atatürk University, TR-25030, Erzurum, Turkey.
| | - Hatice Oğuş
- Department of Basic Sciences, Faculty of Fisheries, Atatürk University, TR-25030, Erzurum, Turkey
| | - Ekrem Sulukan
- Department of Basic Sciences, Faculty of Fisheries, Atatürk University, TR-25030, Erzurum, Turkey
| | - Selim Comaklı
- Department of Pathology, Faculty of Veterinary, Atatürk University, TR-25030, Erzurum, Turkey
| | - Saltuk Buğrahan Ceyhun
- Department of Aquaculture, Faculty of Fisheries, Atatürk University, TR-25030, Erzurum, Turkey; Aquatic Biotechnology Laboratory, Fisheries Faculty, Atatürk University, Erzurum, Turkey
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Guinle C, Núñez-Vázquez EJ, Fernández-Herrera LJ, Corona-Rojas DA, Tovar-Ramírez D. Toxicogenomic Effects of Dissolved Saxitoxin on the Early Life Stages of the Longfin Yellowtail ( Seriola rivoliana). Mar Drugs 2023; 21:597. [PMID: 37999421 PMCID: PMC10671919 DOI: 10.3390/md21110597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/09/2023] [Accepted: 11/16/2023] [Indexed: 11/25/2023] Open
Abstract
Harmful algal blooms (HABs) can produce a variety of noxious effects and, in some cases, the massive mortality of wild and farmed marine organisms. Some HAB species produce toxins that are released into seawater or transferred via food webs (particulate toxin fraction). The objective of the present study was to identify the toxicological effects of subacute exposure to saxitoxin (STX) during embryonic and early larval stages in Seriola rivoliana. Eggs were exposed to dissolved 19 STX (100 μg L-1). The toxic effects of STX were evaluated via the hatching percentage, the activity of three enzymes (protein and alkaline phosphatases and peroxidase), and the expression of four genes (HSF2, Nav1.4b, PPRC1, and DUSP8). A low hatching percentage (less than 5%) was observed in 44 hpf (hours post fertilization) embryos exposed to STX compared to 71% in the unexposed control. At this STX concentration, no oxidative stress in the embryos was evident. However, STX induced the expression of the NaV1.4 channel α-subunit (NaV1.4b), which is the primary target of this toxin. Our results revealed the overexpression of all four candidate genes in STX-intoxicated lecithotrophic larvae, reflecting the activation of diverse cellular processes involved in stress responses (HSF2), lipid metabolism (PPRC1), and MAP kinase signaling pathways associated with cell proliferation and differentiation (DUSP8). The effects of STX were more pronounced in young larvae than in embryos, indicating a stage-specific sensitivity to the toxin.
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Affiliation(s)
- Colleen Guinle
- Centro de Investigaciones Biológicas del Noroeste, Laboratorio de Fisiología Comparada y Genómica Funcional, Av. Instituto Politécnico Nacional 195 Playa Palo de Santa Rita, La Paz 23096, Mexico; (C.G.); (D.A.C.-R.)
| | - Erick Julián Núñez-Vázquez
- Centro de Investigaciones Biológicas del Noroeste, Laboratorio de Toxinas Marinas y Aminoácidos, Av. Instituto Politécnico Nacional 195 Playa Palo de Santa Rita, La Paz 23096, Mexico;
| | - Leyberth José Fernández-Herrera
- Centro de Investigaciones Biológicas del Noroeste, Laboratorio de Toxinas Marinas y Aminoácidos, Av. Instituto Politécnico Nacional 195 Playa Palo de Santa Rita, La Paz 23096, Mexico;
| | - Daniela Alejandra Corona-Rojas
- Centro de Investigaciones Biológicas del Noroeste, Laboratorio de Fisiología Comparada y Genómica Funcional, Av. Instituto Politécnico Nacional 195 Playa Palo de Santa Rita, La Paz 23096, Mexico; (C.G.); (D.A.C.-R.)
| | - Dariel Tovar-Ramírez
- Centro de Investigaciones Biológicas del Noroeste, Laboratorio de Fisiología Comparada y Genómica Funcional, Av. Instituto Politécnico Nacional 195 Playa Palo de Santa Rita, La Paz 23096, Mexico; (C.G.); (D.A.C.-R.)
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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: 5] [Impact Index Per Article: 2.5] [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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Schunter C, Jarrold MD, Munday PL, Ravasi T. Diel pCO 2 fluctuations alter the molecular response of coral reef fishes to ocean acidification conditions. Mol Ecol 2021; 30:5105-5118. [PMID: 34402113 DOI: 10.1111/mec.16124] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 08/02/2021] [Accepted: 08/11/2021] [Indexed: 12/26/2022]
Abstract
Environmental partial pressure of CO2 (pCO2 ) variation can modify the responses of marine organisms to ocean acidification, yet the underlying mechanisms for this effect remain unclear. On coral reefs, environmental pCO2 fluctuates on a regular day-night cycle. Effects of future ocean acidification on coral reef fishes might therefore depend on their response to this diel cycle of pCO2 . To evaluate the effects on the brain molecular response, we exposed two common reef fishes (Acanthochromis polyacanthus and Amphiprion percula) to two projected future pCO2 levels (750 and 1,000 µatm) under both stable and diel fluctuating conditions. We found a common signature to stable elevated pCO2 for both species, which included the downregulation of immediate early genes, indicating lower brain activity. The transcriptional programme was more strongly affected by higher average pCO2 in a stable treatment than for fluctuating treatments, but the largest difference in molecular response was between stable and fluctuating pCO2 treatments. This indicates that a response to a change in environmental pCO2 conditions is different for organisms living in a fluctuating than in stable environments. This differential regulation was related to steroid hormones and circadian rhythm (CR). Both species exhibited a marked difference in the expression of CR genes among pCO2 treatments, possibly accommodating a more flexible adaptive approach in the response to environmental changes. Our results suggest that environmental pCO2 fluctuations might enable reef fishes to phase-shift their clocks and anticipate pCO2 changes, thereby avoiding impairments and more successfully adjust to ocean acidification conditions.
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Affiliation(s)
- Celia Schunter
- Swire Institute of Marine Science, School of Biological Sciences, The University of Hong Kong, Pok Fu Lam, Hong Kong SAR
| | - Michael D Jarrold
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia
| | - Philip L Munday
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia
| | - Timothy Ravasi
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia.,Marine Climate Change Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
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Petroff R, Hendrix A, Shum S, Grant KS, Lefebvre KA, Burbacher TM. Public health risks associated with chronic, low-level domoic acid exposure: A review of the evidence. Pharmacol Ther 2021; 227:107865. [PMID: 33930455 DOI: 10.1016/j.pharmthera.2021.107865] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 12/13/2022]
Abstract
Domoic acid (DA), the causative agent for the human syndrome Amnesic Shellfish Poisoning (ASP), is a potent, naturally occurring neurotoxin produced by common marine algae. DA accumulates in seafood, and humans and wildlife alike can subsequently be exposed when consuming DA-contaminated shellfish or finfish. While strong regulatory limits protect people from the acute effects associated with ASP, DA is an increasingly significant public health concern, particularly for coastal dwelling populations, and there is a growing body of evidence suggesting that there are significant health consequences following repeated exposures to levels of the toxin below current safety guidelines. However, gaps in scientific knowledge make it difficult to precisely determine the risks of contemporary low-level exposure scenarios. The present review characterizes the toxicokinetics and neurotoxicology of DA, discussing results from clinical and preclinical studies after both adult and developmental DA exposure. The review also highlights crucial areas for future DA research and makes the case that DA safety limits need to be reassessed to best protect public health from deleterious effects of this widespread marine toxin.
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Affiliation(s)
- Rebekah Petroff
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Alicia Hendrix
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Sara Shum
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Kimberly S Grant
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Center on Human Development and Disability, University of Washington, Seattle, WA, USA
| | - Kathi A Lefebvre
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd. East, Seattle, WA, USA
| | - Thomas M Burbacher
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Center on Human Development and Disability, University of Washington, Seattle, WA, USA; Infant Primate Research Laboratory, Washington National Primate Research Center, Seattle,WA, USA.
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Burren A, Pietsch C. Distress Regulates Different Pathways in the Brain of Common Carp: A Preliminary Study. Animals (Basel) 2021; 11:ani11020585. [PMID: 33672436 PMCID: PMC7926896 DOI: 10.3390/ani11020585] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 12/31/2022] Open
Abstract
In this study, a stress trial was conducted with common carp, one of the most important species in aquaculture worldwide, to identify relevant gene regulation pathways in different areas of the brain. Acute distress due to exposure to air significantly activated the expression of the immediate early gene c-fos in the telencephalon. In addition, evidence for regulation of the two corticotropin-releasing factor (crf) genes in relation to their binding protein (corticotropin-releasing hormone-binding protein, crh-bp) is presented in this preliminary study. Inferences on the effects of due to exposure to air were obtained by using point estimation, which allows the prediction of a single value. This constitutes the best description to date of the previously generally unknown effects of stress in different brain regions in carp. Furthermore, principal component analyses were performed to reveal possible regulation patterns in the different regions of the fish brain. In conclusion, these preliminary studies on gene regulation in the carp brain that has been influenced by exposure to a stressor reveal that a number of genes may be successfully used as markers for exposure to unfavourable conditions.
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Stumbo A, Poulin R, Ruehle B. Altered neuronal activity in the visual processing region of eye-fluke-infected fish. Parasitology 2021; 148:115-121. [PMID: 33059785 PMCID: PMC11010201 DOI: 10.1017/s0031182020001948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/27/2020] [Accepted: 10/08/2020] [Indexed: 11/06/2022]
Abstract
Fish, like most vertebrates, are dependent on vision to varying degrees for a variety of behaviours such as predator avoidance and foraging. Disruption of this key sensory system therefore should have some impact on the ability of fish to execute these tasks. Eye-flukes, such as Tylodelphys darbyi, often infect fish where they are known to inflict varying degrees of visual impairment. In New Zealand, T. darbyi infects the eyes of Gobiomorphus cotidianus, a freshwater fish, where it resides in the vitreous chamber between the lens and retina. Here, we investigate whether the presence of the parasite in the eye has an impact on neuronal information transfer using the c-Fos gene as a proxy for neuron activation. We hypothesized that the parasite would reduce visual information entering the eye and therefore result in lower c-Fos expression. Interestingly, however, c-Fos expression increased with T. darbyi intensity when fish were exposed to flashes of light. Our results suggest a mechanism for parasite-induced visual disruption when no obvious pathology is caused by infection. The more T. darbyi present the more visual stimuli the fish is presented with, and as such may experience difficulties in distinguishing various features of its external environment.
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Affiliation(s)
- Anthony Stumbo
- Otago Museum, 419 Great King St., Dunedin9016, New Zealand
- Department of Zoology, University of Otago, 340 Great King St., Dunedin9016, New Zealand
| | - Robert Poulin
- Department of Zoology, University of Otago, 340 Great King St., Dunedin9016, New Zealand
| | - Brandon Ruehle
- Department of Zoology, University of Otago, 340 Great King St., Dunedin9016, New Zealand
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Ellison AR, Uren Webster TM, Rodriguez-Barreto D, de Leaniz CG, Consuegra S, Orozco-terWengel P, Cable J. Comparative transcriptomics reveal conserved impacts of rearing density on immune response of two important aquaculture species. FISH & SHELLFISH IMMUNOLOGY 2020; 104:192-201. [PMID: 32534231 DOI: 10.1016/j.fsi.2020.05.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/13/2020] [Accepted: 05/15/2020] [Indexed: 06/11/2023]
Abstract
Infectious diseases represent an important barrier to sustainable aquaculture development. Rearing density can substantially impact fish productivity, health and welfare in aquaculture, including growth rates, behaviour and, crucially, immune activity. Given the current emphasis on aquaculture diversification, stress-related indicators broadly applicable across species are needed. Utilising an interspecific comparative transcriptomic (RNAseq) approach, we compared gill gene expression responses of Atlantic salmon (Salmo salar) and Nile tilapia (Oreochromis niloticus) to rearing density and Saprolegnia parasitica infection. Salmon reared at high-density showed increased expression of stress-related markers (e.g. c-fos and hsp70), and downregulation of innate immune genes. Upon pathogen challenge, only salmon reared at low density exhibited increased expression of inflammatory interleukins and lymphocyte-related genes. Tilapia immunity, in contrast, was impaired at low-density. Using overlapping gene ontology enrichment and gene ortholog analyses, we found that density-related stress similarly impacted salmon and tilapia in key immune pathways, altering the expression of genes vital to inflammatory and Th17 responses to pathogen challenge. Given the challenges posed by ectoparasites and gill diseases in fish farms, this study underscores the importance of optimal rearing densities for immunocompetence, particularly for mucosal immunity. Our comparative transcriptomics analyses identified density stress impacted immune markers common across different fish taxa, providing key molecular targets with potential for monitoring and enhancing aquaculture resilience in a wide range of farmed species.
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Affiliation(s)
- Amy R Ellison
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK.
| | | | | | | | - Sofia Consuegra
- Biosciences Department, Swansea University, Swansea, SA2 8PP, UK.
| | | | - Jo Cable
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK.
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Cannabinoid modulation of zebrafish fear learning and its functional analysis investigated by c-Fos expression. Pharmacol Biochem Behav 2016; 153:18-31. [PMID: 27965084 DOI: 10.1016/j.pbb.2016.12.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 12/05/2016] [Accepted: 12/09/2016] [Indexed: 12/31/2022]
Abstract
It has been shown that zebrafish fear learning proceeds in the same way as reported for rodents. However, in zebrafish fear learning it is possible to substitute the use of electric shocks as unconditioned stimulus and utilize the inborn fear responses to the alarm substance Schreckstoff, instead. The skin extract Schreckstoff elicits typical fear reactions such as preferred bottom dwelling, swimming in a tighter shoal, erratic movements and freezing. This natural fear behavior can be transferred from Schreckstoff to any other sensory stimulus by associative conditioning (fear learning). We presented Schreckstoff simultaneously with a red light stimulus and tested the effectiveness of fear learning during memory retrieval. The two brain regions known to be relevant for learning in zebrafish are the medial and the lateral pallium of the dorsal telencephalon, both containing rich expressions of the endocannabinoid receptor CB1. To test the influence of the zebrafish endocannabinoid system on fear acquisition learning, an experimental group of ten fish was pretreated with the CB1 receptor agonist THC (Δ9-tetrahydrocannabinol; 100nM for 1h). We found that CB1 activation significantly inhibited acquisition of fear learning, possibly by impairing stimulus encoding processes in pallial areas. This was supported by analyzes of c-Fos expression in the brains of experimental animals. Schreckstoff exposure during fear acquisition learning and memory retrieval during red light presentation increased the number of labelled cells in pallial structures, but in no other brain region investigated (e.g. striatum, thalamus, and habenula). THC administration before fear conditioning significantly decreased c-Fos expression in these structures to a level similar to the control group without Schreckstoff experience, suggesting that Schreckstoff induced fear learning requires brain circuits restricted mainly to pallial regions of the dorsal telencephalon.
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Diehl F, Ramos PB, Dos Santos JM, Barros DM, Yunes JS. Behavioral alterations induced by repeated saxitoxin exposure in drinking water. J Venom Anim Toxins Incl Trop Dis 2016; 22:18. [PMID: 27190499 PMCID: PMC4869272 DOI: 10.1186/s40409-016-0072-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 05/09/2016] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Blooms of the saxitoxin-producing cyanobacterium Cylindrospermopsis raciborskii have been contaminating drinking water reservoirs in Brazil for many years. Although acute effects of saxitoxin intoxication are well known, chronic deleterious outcomes caused by repeated saxitoxin exposure still require further investigation. The aim of the present work is to investigate the effects of consumption of drinking water contaminated with C. raciborskii for 30 days on learning and memory processes in rats. METHODS The effects of saxitoxin (3 or 9 μg/L STX equivalents) or cyanobacteria on behavior was determined using the open field habituation task, elevated plus maze anxiety model task, inhibitory avoidance task, and referential Morris water maze task. RESULTS No effects of saxitoxin consumption was observed on anxiety and motor exploratory parameters in the elevated plus maze and open field habituation tasks, respectively. However, groups treated with 9 μg/L STX equivalents displayed a decreased memory performance in the inhibitory avoidance and Morris water maze tasks. CONCLUSIONS These results suggest an amnesic effect of saxitoxin on aversive and spatial memories.
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Affiliation(s)
- Felipe Diehl
- Postgraduate Program in Physical, Chemical and Geological Oceanography, Institute of Oceanography, Federal University of Rio Grande (FURG), Rio Grande, RS Brazil ; Institute of Oceanography, Federal University of Rio Grande (FURG), Caixa Postal 474, Rio Grande, RS CEP 96203-900 Brazil
| | - Patricia Baptista Ramos
- Postgraduate Program in Physical, Chemical and Geological Oceanography, Institute of Oceanography, Federal University of Rio Grande (FURG), Rio Grande, RS Brazil
| | - Juliane Marques Dos Santos
- Postgraduate Program in Physical, Chemical and Geological Oceanography, Institute of Oceanography, Federal University of Rio Grande (FURG), Rio Grande, RS Brazil
| | - Daniela Martí Barros
- Postgraduate Program in Compared Animal Physiology, Institute of Biological Sciences, Federal University of Rio Grande (FURG), Rio Grande, RS Brazil
| | - João Sarkis Yunes
- Postgraduate Program in Physical, Chemical and Geological Oceanography, Institute of Oceanography, Federal University of Rio Grande (FURG), Rio Grande, RS Brazil
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Topal A, Atamanalp M, Oruç E, Halıcı MB, Şişecioğlu M, Erol HS, Gergit A, Yılmaz B. Neurotoxic effects of nickel chloride in the rainbow trout brain: Assessment of c-Fos activity, antioxidant responses, acetylcholinesterase activity, and histopathological changes. FISH PHYSIOLOGY AND BIOCHEMISTRY 2015; 41:625-634. [PMID: 25666867 DOI: 10.1007/s10695-015-0033-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/03/2015] [Indexed: 06/04/2023]
Abstract
The aim of this study was to determine the biochemical, immunohistochemical, and histopathological effects of nickel chloride (Ni) in the rainbow trout brain. Fish were exposed to Ni concentrations (1 mg/L and 2 mg/L) for 21 days. At the end of the experimental period, brain tissues were taken from all fish for c-Fos activity and histopathological examination and determination of acetylcholinesterase (AChE), superoxide dismutase (SOD), catalase (CAT) enzyme activities, lipid peroxidation (LPO), and glutathione (GSH) levels. Our results showed that Ni treatment caused a significant increase in the brain SOD activity and in LPO and GSH levels (p < 0.05), but it significantly decreased AChE and CAT enzyme activities (p < 0.05). Strong induction in c-Fos was observed in some cerebral and cerebellar regions of fish exposed to Ni concentrations when compared with the control group. However, c-Fos activity was decreased in necrotic Purkinje cells. Brain tissues were characterized by demyelination and necrotic changes. These results suggested that Ni treatment causes oxidative stress, changes in c-Fos activity, and histopathological damage in the fish brain.
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Affiliation(s)
- Ahmet Topal
- Department of Basic Sciences, Faculty of Fisheries, Ataturk University, 25240, Erzurum, Turkey,
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Schulte PM. What is environmental stress? Insights from fish living in a variable environment. ACTA ACUST UNITED AC 2014; 217:23-34. [PMID: 24353201 DOI: 10.1242/jeb.089722] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Although the term environmental stress is used across multiple fields in biology, the inherent ambiguity associated with its definition has caused confusion when attempting to understand organismal responses to environmental change. Here I provide a brief summary of existing definitions of the term stress, and the related concepts of homeostasis and allostasis, and attempt to unify them to develop a general framework for understanding how organisms respond to environmental stressors. I suggest that viewing stressors as environmental changes that cause reductions in performance or fitness provides the broadest and most useful conception of the phenomenon of stress. I examine this framework in the context of animals that have evolved in highly variable environments, using the Atlantic killifish, Fundulus heteroclitus, as a case study. Consistent with the extreme environmental variation that they experience in their salt marsh habitats, killifish have substantial capacity for both short-term resistance and long-term plasticity in the face of changing temperature, salinity and oxygenation. There is inter-population variation in the sensitivity of killifish to environmental stressors, and in their ability to acclimate, suggesting that local adaptation can shape the stress response even in organisms that are broadly tolerant and highly plastic. Whole-organism differences between populations in stressor sensitivity and phenotypic plasticity are reflected at the biochemical and molecular levels in killifish, emphasizing the integrative nature of the response to environmental stressors. Examination of this empirical example highlights the utility of using an evolutionary perspective on stressors, stress and stress responses.
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Affiliation(s)
- Patricia M Schulte
- Department of Zoology, 6270 University Blvd, University of British Columbia, Vancouver, BC, V6T 1Z4 Canada
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Al-Sammak MA, Hoagland KD, Cassada D, Snow DD. Co-occurrence of the cyanotoxins BMAA, DABA and anatoxin-a in Nebraska reservoirs, fish, and aquatic plants. Toxins (Basel) 2014; 6:488-508. [PMID: 24476710 PMCID: PMC3942747 DOI: 10.3390/toxins6020488] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 12/19/2013] [Accepted: 01/17/2014] [Indexed: 11/17/2022] Open
Abstract
Several groups of microorganisms are capable of producing toxins in aquatic environments. Cyanobacteria are prevalent blue green algae in freshwater systems, and many species produce cyanotoxins which include a variety of chemical irritants, hepatotoxins and neurotoxins. Production and occurrence of potent neurotoxic cyanotoxins β-N-methylamino-l-alanine (BMAA), 2,4-diaminobutyric acid dihydrochloride (DABA), and anatoxin-a are especially critical with environmental implications to public and animal health. Biomagnification, though not well understood in aquatic systems, is potentially relevant to both human and animal health effects. Because little is known regarding their presence in fresh water, we investigated the occurrence and potential for bioaccumulation of cyanotoxins in several Nebraska reservoirs. Collection and analysis of 387 environmental and biological samples (water, fish, and aquatic plant) provided a snapshot of their occurrence. A sensitive detection method was developed using solid phase extraction (SPE) in combination with high pressure liquid chromatography-fluorescence detection (HPLC/FD) with confirmation by liquid chromatography-tandem mass spectrometry (LC/MS/MS). HPLC/FD detection limits ranged from 5 to 7 µg/L and LC/MS/MS detection limits were <0.5 µg/L, while detection limits for biological samples were in the range of 0.8–3.2 ng/g depending on the matrix. Based on these methods, measurable levels of these neurotoxic compounds were detected in approximately 25% of the samples, with detections of BMAA in about 18.1%, DABA in 17.1%, and anatoxin-a in 11.9%.
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Affiliation(s)
- Maitham Ahmed Al-Sammak
- Environmental Health, Occupational Health, & Toxicology, Tropical Biological Researches Unit, College of Science, University of Baghdad, Baghdad 10071, Iraq; E-Mail:
- Nebraska Water Center and School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE 68583, USA; E-Mail:
| | - Kyle D. Hoagland
- School of Natural Resources, University of Nebraska, Lincoln, NE 68583, USA; E-Mail:
| | - David Cassada
- Nebraska Water Center and School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE 68583, USA; E-Mail:
| | - Daniel D. Snow
- Nebraska Water Center and School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE 68583, USA; E-Mail:
- Author to whom correspondence should be addressed: E-Mail: ; Tel.: +1-402-472-7539; Fax: +1-402-472-9599
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Hamilton TJ, Paz-Yepes J, Morrison RA, Palenik B, Tresguerres M. Exposure to bloom-like concentrations of two marine Synechococcus cyanobacteria (strains CC9311 and CC9902) differentially alters fish behaviour. CONSERVATION PHYSIOLOGY 2014; 2:cou020. [PMID: 27293641 PMCID: PMC4732467 DOI: 10.1093/conphys/cou020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 04/23/2014] [Accepted: 04/26/2014] [Indexed: 05/22/2023]
Abstract
Coastal California experiences large-scale blooms of Synechococcus cyanobacteria, which are predicted to become more prevalent by the end of the 21st century as a result of global climate change. This study investigated whether exposure to bloom-like concentrations of two Synechococcus strains, CC9311 and CC9902, alters fish behaviour. Black perch (Embiotoca jacksoni) were exposed to Synechococcus strain CC9311 or CC9902 (1.5 × 10(6) cells ml(-1)) or to control seawater in experimental aquaria for 3 days. Fish movement inside a testing arena was then recorded and analysed using video camera-based motion-tracking software. Compared with control fish, fish exposed to CC9311 demonstrated a significant preference for the dark zone of the tank in the light-dark test, which is an indication of increased anxiety. Furthermore, fish exposed to CC9311 also had a statistically significant decrease in velocity and increase in immobility and they meandered more in comparison to control fish. There was a similar trend in velocity, immobility and meandering in fish exposed to CC9902, but there were no significant differences in behaviour or locomotion between this group and control fish. Identical results were obtained with a second batch of fish. Additionally, in this second trial we also investigated whether fish would recover after a 3 day period in seawater without cyanobacteria. Indeed, there were no longer any significant differences in behaviour among treatments, demonstrating that the sp. CC9311-induced alteration of behaviour is reversible. These results demonstrate that blooms of specific marine Synechococcus strains can induce differential sublethal effects in fish, namely alterations light-dark preference behaviour and motility.
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Affiliation(s)
- T. J. Hamilton
- Department of Psychology, MacEwan University, Edmonton, Canada
| | - J. Paz-Yepes
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, CA, USA
- Institut de Biologie de I'Ecole Normale Supérieure, CNRS, UMR 8197, 46 rue d'Ulm, 75230 Paris, France
| | - R. A. Morrison
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, CA, USA
| | - B. Palenik
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, CA, USA
| | - M. Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, CA, USA
- Corresponding author: Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive MC#0202, La Jolla, CA 92093-0202, USA. Tel: +1 858 534 5895.
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15
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Costa PR, Pereira P, Guilherme S, Barata M, Santos MA, Pacheco M, Pousão-Ferreira P. Hydroxybenzoate paralytic shellfish toxins induce transient GST activity depletion and chromosomal damage in white seabream (Diplodus sargus). MARINE ENVIRONMENTAL RESEARCH 2012; 79:63-69. [PMID: 22710085 DOI: 10.1016/j.marenvres.2012.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/07/2012] [Accepted: 05/11/2012] [Indexed: 06/01/2023]
Abstract
Fish are routinely exposed to harmful algal blooms that produce noxious compounds and impact the marine food web. This study investigates the role of phase I and II detoxification enzymes on metabolism of the novel paralytic shellfish toxins (PSTs), the hydroxybenzoate analogues recently discovered in Gymnodinium catenatum strains, in the liver of white seabream, assessing ethoxyresorufin-O-deethylase (EROD) and glutathione S-transferase (GST) activities. Additionally, the genotoxic potential of hydroxybenzoate PSTs was examined through the erythrocytic nuclear abnormality (ENA) assay. Fish were injected with hydroxybenzoate PSTs into the coelomic cavity and sacrificed 2 and 6 days later for biochemical and cytogenetic analyses. While the activity of EROD was unresponsive to toxins, a significant GST activity decrease was observed at 2 days after injection indicating an impairment of this line of the detoxification system. The genotoxic potential of PSTs was demonstrated by the induction of clastogenic/aneugenic effects at 2 days, as measured by the ENA assay. Overall, this study contributes to better understand the impact of toxins produced by G. catenatum blooms in fish, revealing effects that, even transitory, point out a risk associated to hydroxybenzoate analogues.
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Affiliation(s)
- Pedro Reis Costa
- IPIMAR - National Institute for Biological Resources (INRB/IPIMAR), Av. Brasília, 1449-006 Lisboa, Portugal.
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16
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Bakke MJ, Horsberg TE. Kinetic properties of saxitoxin in Atlantic salmon (Salmo salar) and Atlantic cod (Gadus morhua). Comp Biochem Physiol C Toxicol Pharmacol 2010; 152:444-50. [PMID: 20656058 DOI: 10.1016/j.cbpc.2010.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 07/13/2010] [Accepted: 07/14/2010] [Indexed: 11/26/2022]
Abstract
The disposition of STX in Atlantic salmon (Salmo salar) and Atlantic cod (Gadus morhua) was studied after intraperitoneal (IP) injection (5 microg STX/kg bm and 3.43 microg (3)H-STXeq/kg bw respectively), intravenous (IV) injection (5 microg STX/kg bm, only salmon) and waterborne exposure (50 microg STXeq/L, only salmon). Plasma concentrations in salmon were quantified using a receptor binding assay and cod tissues were analyzed using scintillation counting of tissue extracts and autoradiography of whole fish slices. The estimated elimination half-life (T(1/2)) after IV administration of STX in salmon was 102.6 min. The volume of distribution (Vz) was observed to be 467.2 mL/kg and the total body clearance (Cl(T)) was 3.2 mL/min/kg. Waterborne exposure clearly showed that salmon absorbed PSP toxins directly from the water. In cod, (3)H-STX was observed in gills, muscle, brain, liver and posterior kidney from 30 to 480 min. The lowest concentrations of (3)H-STX were found in brain and muscle, whereas posterior kidney contained the majority of the toxin. Autoradiograms confirmed the high levels of (3)H-STX in the kidneys, indicating that renal excretion was the main elimination route. Buildup of harmful levels in edible tissue is not very likely due to the low concentrations accumulated in muscle tissue and rapid excretion.
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Affiliation(s)
- Marit Jørgensen Bakke
- Department of Pharmacology and Toxicology, Norwegian School of Veterinary Science, Oslo, Norway.
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Nogueira I, Lobo-da-Cunha A, Afonso A, Rivera S, Azevedo J, Monteiro R, Cervantes R, Gago-Martinez A, Vasconcelos V. Toxic effects of domoic acid in the seabream Sparus aurata. Mar Drugs 2010; 8:2721-32. [PMID: 21116416 PMCID: PMC2993002 DOI: 10.3390/md8102721] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 10/07/2010] [Accepted: 10/14/2010] [Indexed: 11/16/2022] Open
Abstract
Neurotoxicity induced in fish by domoic acid (DA) was assessed with respect to occurrence of neurotoxic signs, lethality, and histopathology by light microscopy. Sparus aurata were exposed to a single dose of DA by intraperitoneal (i.p.) injection of 0, 0.45, 0.9, and 9.0 mg DA kg(-1) bw. Mortality (66.67 ± 16.67%) was only observed in dose of 9.0 mg kg(-1) bw. Signs of neurological toxicity were detected for the doses of 0.9 and 9.0 mg DA kg(-1) bw. Furthermore, the mean concentrations (±SD) of DA detected by HPLC-UV in extracts of brain after exposure to 9.0 mg DA kg(-1) bw were 0.61 ± 0.01, 0.96 ± 0.00, and 0.36 ± 0.01 mg DA kg(-1) tissue at 1, 2, and 4 hours. The lack of major permanent brain damage in S. aurata, and reversibility of neurotoxic signs, suggest that lower susceptibility to DA or neuronal recovery occurs in affected individuals.
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Affiliation(s)
- Isabel Nogueira
- CIIMAR/CIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas 177-289, 4150-123 Porto, Portugal; E-Mails: (I.N.); (A.A.); (J.A.)
| | - Alexandre Lobo-da-Cunha
- CIIMAR/CIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas 177-289, 4150-123 Porto, Portugal; E-Mails: (I.N.); (A.A.); (J.A.)
- Laboratório de Biologia Celular, Instituto de Ciências Biomédicas Abel Salazar, ICBAS, Lg. Abel Salazar 2, 4099-003 Porto, Portugal; E-Mail: (A.L.C.)
| | - António Afonso
- CIIMAR/CIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas 177-289, 4150-123 Porto, Portugal; E-Mails: (I.N.); (A.A.); (J.A.)
| | - Socorro Rivera
- Departamento de Química Analítica, Facultad de Química, As Lagoas Marcosende C.P. 36210, Spain; E-Mails: (S.R.); (A.G.-M.)
| | - Joana Azevedo
- CIIMAR/CIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas 177-289, 4150-123 Porto, Portugal; E-Mails: (I.N.); (A.A.); (J.A.)
| | - Rogério Monteiro
- CIIMAR/CIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas 177-289, 4150-123 Porto, Portugal; E-Mails: (I.N.); (A.A.); (J.A.)
- Laboratório de Histologia e Embriologia, Instituto de Ciências Biomédicas Abel Salazar, ICBAS, Lg. Abel Salazar 2, 4099-003 Porto, Portugal; E-Mail: (R.M.)
| | - Rosa Cervantes
- Departamento de Química Analítica, Facultad de Química, As Lagoas Marcosende C.P. 36210, Spain; E-Mails: (S.R.); (A.G.-M.)
| | - Ana Gago-Martinez
- Departamento de Química Analítica, Facultad de Química, As Lagoas Marcosende C.P. 36210, Spain; E-Mails: (S.R.); (A.G.-M.)
| | - Vítor Vasconcelos
- CIIMAR/CIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas 177-289, 4150-123 Porto, Portugal; E-Mails: (I.N.); (A.A.); (J.A.)
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 4169-007 Porto, Portugal
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Bakke MJ, Hustoft HK, Horsberg TE. Subclinical effects of saxitoxin and domoic acid on aggressive behaviour and monoaminergic turnover in rainbow trout (Oncorhynchus mykiss). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 99:1-9. [PMID: 20409597 DOI: 10.1016/j.aquatox.2010.03.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 03/03/2010] [Accepted: 03/23/2010] [Indexed: 05/29/2023]
Abstract
The algal produced neurotoxins saxitoxin and domoic acid may have serious effects on marine life and can be responsible for the intoxication of for instance sea mammals, sea birds and fish. Given that farmed fish cannot escape algal blooms, they may be more susceptible to intoxication than wild stocks. In the present study, subclinical effects of saxitoxin and domoic on aggressive behaviour and monoaminergic systems in the brain of the rainbow trout (Oncorhynchus mykiss) were investigated. The resident-intruder test was used to measure aggression where only the resident fish were subjected to the toxins and analysed for monoamines and their metabolites. The resident-intruder test was carried out on two consecutive days. On day one basal aggression was measured in the four groups. On day two three of the groups were injected with subclinical doses of one of the following: saxitoxin (1.752 microg/kg bw), domoic (0.75 mg/kg bw) or 0.9% saline solution. This was performed 30 min prior to the aggression test. Handling stress and injection affected aggressive behaviour, cortisol and the serotonergic system in telencephalic brain regions. Cortisol levels were elevated in all of the injected groups when compared to the control group. An increase in serotonergic turnover was evident when all injected groups were pooled and compared to the control group. All together this suggests that the handling stress in connection with the injection was similar in all of the three injected groups. In contrast to both the undisturbed control group and the toxin-injected groups, the saline-injected group displayed a reduction in aggressive behaviour which was evident in increased attack latency. Furthermore the domoic injected group displayed more aggressive attacks towards their conspecifics than the saline-injected group. Consequently the two toxins appear to mask the stress induced alteration in aggressive behaviour. Monoamine levels and monoaminergic turnover could not be demonstrated to be directly affected by the two toxins at the given doses in the investigated brain regions (dorsal and ventral parts of telencephalon, optic tectum, locus coeruleus, raphe nucleus, molecular and granular layer of cerebellum). This could indicate that the toxins mediate aggressive behaviour either through other systems than the monoaminergic systems, such as neuroactive amino acids, or that the mediation occurs in other brain regions.
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Affiliation(s)
- Marit Jørgensen Bakke
- Department of Pharmacology and Toxicology, Norwegian School of Veterinary Science, N-0033 Oslo, Norway.
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Lefebvre KA, Tilton SC, Bammler TK, Beyer RP, Srinouanprachan S, Stapleton PL, Farin FM, Gallagher EP. Gene expression profiles in zebrafish brain after acute exposure to domoic acid at symptomatic and asymptomatic doses. Toxicol Sci 2008; 107:65-77. [PMID: 18936300 DOI: 10.1093/toxsci/kfn207] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Domoic acid (DA) is a neuroexcitatory amino acid that is naturally produced by some marine diatom species of the genus Pseudo-nitzschia. Ingestion of DA-contaminated seafood by humans results in a severe neurotoxic disease known as amnesic shellfish poisoning (ASP). Clinical signs of ASP include seizures and neuronal damage from activation of ionotropic glutamate receptors. However, the impacts of DA exposure at levels below those known to induce outward signs of neurobehavioral exicitotoxicity have not been well characterized. To further understand the mechanisms of neurotoxic injury associated with DA exposure, we examined the transcriptome of whole brains from zebrafish (Danio rerio) receiving intracoelomic (IC) injection of DA at both symptomatic and asymptomatic doses. A majority of zebrafish exposed to high-dose DA (1.2 microg DA/g) exhibited clinical signs of neuroexcitotoxicity (EC(50) of 0.86 microg DA/g) within 5-20 min of IC injection. All zebrafish receiving low-dose DA (0.47 microg DA/g) or vehicle only maintained normal behavior. Microarray analysis of symptomatic and asymptomatic exposures collectively yielded 306 differentially expressed genes (1.5-fold, p </= 0.05) predominately represented by signal transduction, ion transport, and transcription factor functional categories. Transcriptional profiles were suggestive of neuronal apoptosis following an overwhelming of protective adaptive pathways. Further, potential molecular biomarkers of neuropathic injury, including the zebrafish homolog of human NDRG4, were identified and may be relevant to DA exposure levels below that causing neurobehavioral injury. In general, DA-modulated gene expression was consistent with other model species thereby validating zebrafish as an appropriate vertebrate model to study mechanisms of DA neurotoxicity. These data provide a basis for identifying pathways of DA-induced injury as well as biomarkers of asymptomatic and symptomatic DA exposure levels.
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Affiliation(s)
- Kathi A Lefebvre
- Marine Biotoxins Program, National Oceanic and Atmospheric Administration (NOAA) Fisheries/Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, Washington 98125, USA
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Paul VJ, Arthur KE, Ritson-Williams R, Ross C, Sharp K. Chemical defenses: from compounds to communities. THE BIOLOGICAL BULLETIN 2007; 213:226-251. [PMID: 18083964 DOI: 10.2307/25066642] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Marine natural products play critical roles in the chemical defense of many marine organisms and in some cases can influence the community structure of entire ecosystems. Although many marine natural products have been studied for biomedical activity, yielding important information about their biochemical effects and mechanisms of action, much less is known about ecological functions. The way in which marine consumers perceive chemical defenses can influence their health and survival and determine whether some natural products persist through a food chain. This article focuses on selected marine natural products, including okadaic acid, brevetoxins, lyngbyatoxin A, caulerpenyne, bryostatins, and isocyano terpenes, and examines their biosynthesis (sometimes by symbiotic microorganisms), mechanisms of action, and biological and ecological activity. We selected these compounds because their impacts on marine organisms and communities are some of the best-studied among marine natural products. We discuss the effects of these compounds on consumer behavior and physiology, with an emphasis on neuroecology. In addition to mediating a variety of trophic interactions, these compounds may be responsible for community-scale ecological impacts of chemically defended organisms, such as shifts in benthic and pelagic community composition. Our examples include harmful algal blooms; the invasion of the Mediterranean by Caulerpa taxifolia; overgrowth of coral reefs by chemically rich macroalgae and cyanobacteria; and invertebrate chemical defenses, including the role of microbial symbionts in compound production.
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Affiliation(s)
- Valerie J Paul
- Smithsonian Marine Station at Fort Pierce, 701 Seaway Drive, Fort Pierce, Florida 34949, USA.
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Bakke MJ, Horsberg TE. Effects of algal-produced neurotoxins on metabolic activity in telencephalon, optic tectum and cerebellum of Atlantic salmon (Salmo salar). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2007; 85:96-103. [PMID: 17870190 DOI: 10.1016/j.aquatox.2007.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 08/07/2007] [Accepted: 08/08/2007] [Indexed: 05/17/2023]
Abstract
Neurotoxins from algal blooms have been reported to cause mortality in a variety of species, including sea birds, sea mammals and fish. Farmed fish cannot escape harmful algal blooms and their potential toxins, thus they are more vulnerable for exposure than wild stocks. Sublethal doses of the toxins are likely to affect fish behaviour and may impair cognitive abilities. In the present study, changes in the metabolic activity in different parts of the Atlantic salmon (Salmo salar) brain involved in central integration and cognition were investigated after exposure to sublethal doses of three algal-produced neurotoxins; saxitoxin (STX), brevetoxin (BTX) and domoic acid (DA). Fish were randomly selected to four groups for i.p. injection of saline (control) or one of the neurotoxins STX (10 microg STX/kg bw), BTX (68 microg BTX/kg bw) or DA (6 mg DA/kg bw). In addition, 14C-2-deoxyglucose was i.m. injected to measure brain metabolic activity by autoradiography. The three regions investigated were telencephalon (Tel), optic tectum (OT) and cerebellum (Ce). There were no differences in the metabolic activity after STX and BTX exposure compared to the control in these regions. However, a clear increase was observed after DA exposure. When the subregions with the highest metabolic rate were pseudocoloured in the three brain regions, the three toxins caused distinct differences in the respective patterns of metabolic activation. Fish exposed to STX displayed similar patterns as the control fish, whereas fish exposed to BTX and DA showed highest metabolic activity in subregions different from the control group. All three neurotoxins affected subregions that are believed to be involved in cognitive abilities in fish.
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Affiliation(s)
- Marit Jørgensen Bakke
- Department of Pharmacology and Toxicology, Norwegian School of Veterinary Science, PO Box 8146 Dep., N-0033 Oslo, Norway
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