1
|
Pinto A, Botelho MJ, Churro C, Asselman J, Pereira P, Pereira JL. A review on aquatic toxins - Do we really know it all regarding the environmental risk posed by phytoplankton neurotoxins? JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118769. [PMID: 37597370 DOI: 10.1016/j.jenvman.2023.118769] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 07/24/2023] [Accepted: 08/09/2023] [Indexed: 08/21/2023]
Abstract
Aquatic toxins are potent natural toxins produced by certain cyanobacteria and marine algae species during harmful cyanobacterial and algal blooms (CyanoHABs and HABs, respectively). These harmful bloom events and the toxins produced during these events are a human and environmental health concern worldwide, with occurrence, frequency and severity of CyanoHABs and HABs being predicted to keep increasing due to ongoing climate change scenarios. These contexts, as well as human health consequences of some toxins produced during bloom events have been thoroughly reviewed before. Conversely, the wider picture that includes the non-human biota in the assessment of noxious effects of toxins is much less covered in the literature and barely covered by review works. Despite direct human exposure to aquatic toxins and related deleterious effects being responsible for the majority of the public attention to the blooms' problematic, it constitutes a very limited fraction of the real environmental risk posed by these toxins. The disruption of ecological and trophic interactions caused by these toxins in the aquatic biota building on deleterious effects they may induce in different species is paramount as a modulator of the overall magnitude of the environmental risk potentially involved, thus necessarily constraining the quality and efficiency of the management strategies that should be placed. In this way, this review aims at updating and consolidating current knowledge regarding the adverse effects of aquatic toxins, attempting to going beyond their main toxicity pathways in human and related models' health, i.e., also focusing on ecologically relevant model organisms. For conciseness and considering the severity in terms of documented human health risks as a reference, we restricted the detailed revision work to neurotoxic cyanotoxins and marine toxins. This comprehensive revision of the systemic effects of aquatic neurotoxins provides a broad overview of the exposure and the hazard that these compounds pose to human and environmental health. Regulatory approaches they are given worldwide, as well as (eco)toxicity data available were hence thoroughly reviewed. Critical research gaps were identified particularly regarding (i) the toxic effects other than those typical of the recognized disease/disorder each toxin causes following acute exposure in humans and also in other biota; and (ii) alternative detection tools capable of being early-warning signals for aquatic toxins occurrence and therefore provide better human and environmental safety insurance. Future directions on aquatic toxins research are discussed in face of the existent knowledge, with particular emphasis on the much-needed development and implementation of effective alternative (eco)toxicological biomarkers for these toxins. The wide-spanning approach followed herein will hopefully stimulate future research more broadly addressing the environmental hazardous potential of aquatic toxins.
Collapse
Affiliation(s)
- Albano Pinto
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Portugal.
| | - Maria João Botelho
- IPMA, Portuguese Institute for the Sea and Atmosphere, Av. Alfredo Magalhães Ramalho 6, 1495-165, Algés, Portugal; CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal
| | - Catarina Churro
- IPMA, Portuguese Institute for the Sea and Atmosphere, Av. Alfredo Magalhães Ramalho 6, 1495-165, Algés, Portugal; CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal
| | - Jana Asselman
- Blue Growth Research Lab, Ghent University, Bluebridge Building, Ostend Science Park 1, 8400, Ostend, Belgium
| | - Patrícia Pereira
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Portugal
| | - Joana Luísa Pereira
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Portugal
| |
Collapse
|
2
|
Finol-Urdaneta RK, Zhorov BS, Baden DG, Adams DJ. Brevetoxin versus Brevenal Modulation of Human Nav1 Channels. Mar Drugs 2023; 21:396. [PMID: 37504927 PMCID: PMC10382042 DOI: 10.3390/md21070396] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/29/2023] Open
Abstract
Brevetoxins (PbTx) and brevenal are marine ladder-frame polyethers. PbTx binds to and activates voltage-gated sodium (Nav) channels in native tissues, whereas brevenal antagonizes these actions. However, the effects of PbTx and brevenal on recombinant Nav channel function have not been systematically analyzed. In this study, the PbTx-3 and brevenal modulation of tissue-representative Nav channel subtypes Nav1.2, Nav1.4, Nav1.5, and Nav1.7 were examined using automated patch-clamp. While PbTx-3 and brevenal elicit concentration-dependent and subtype-specific modulatory effects, PbTx-3 is >1000-fold more potent than brevenal. Consistent with effects observed in native tissues, Nav1.2 and Nav1.4 channels were PbTx-3- and brevenal-sensitive, whereas Nav1.5 and Nav1.7 appeared resistant. Interestingly, the incorporation of brevenal in the intracellular solution caused Nav channels to become less sensitive to PbTx-3 actions. Furthermore, we generated a computational model of PbTx-2 bound to the lipid-exposed side of the interface between domains I and IV of Nav1.2. Our results are consistent with competitive antagonism between brevetoxins and brevenal, setting a basis for future mutational analyses of Nav channels' interaction with brevetoxins and brevenal. Our findings provide valuable insights into the functional modulation of Nav channels by brevetoxins and brevenal, which may have implications for the development of new Nav channel modulators with potential therapeutic applications.
Collapse
Affiliation(s)
- Rocio K Finol-Urdaneta
- Illawarra Health & Medical Research Institute (IHMRI), Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Boris S Zhorov
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223 Saint Petersburg, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Daniel G Baden
- Center for Marine Science, University of North Carolina Wilmington MARBIONC, Wilmington, NC 28409, USA
| | - David J Adams
- Illawarra Health & Medical Research Institute (IHMRI), Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522, Australia
| |
Collapse
|
3
|
Keeler DM, Grandal MK, McCall JR. Brevenal, a Marine Natural Product, is Anti-Inflammatory and an Immunomodulator of Macrophage and Lung Epithelial Cells. Mar Drugs 2019; 17:md17030184. [PMID: 30897777 PMCID: PMC6470468 DOI: 10.3390/md17030184] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/14/2019] [Accepted: 03/17/2019] [Indexed: 12/13/2022] Open
Abstract
Chronic respiratory diseases, including chronic obstructive pulmonary disease (COPD), cystic fibrosis, and asthma, are some of the leading causes of illness and fatalities worldwide. The search for novel treatments led to the exploration of marine natural products as drug candidates to combat the debilitating effects of mucus accumulation and chronic inflammation. Previous research showed that an alga-derived compound, brevenal, could attenuate the effects of inflammatory agents, but the mechanisms by which it exerted its effects remained unclear. We investigated the effects of brevenal on lipopolysaccharide (LPS) induced cytokine/chemokine production from murine macrophages and human lung epithelial cells. It was found that brevenal reduces proinflammatory mediator secretion while preserving anti-inflammatory secretion from these cells. Furthermore, we found that brevenal does not alter cell surface Toll-like receptor 4 (TLR4) expression, thereby maintaining the cells' ability to respond to bacterial infection. However, brevenal does alter macrophage activation states, as demonstrated by reduced expression of both M1 and M2 phenotype markers, indicating this putative anti-inflammatory drug shifts innate immune cells to a less active state. Such a mechanism of action would be ideal for reducing inflammation in the lung, especially with patients suffering from chronic respiratory diseases, where inflammation can be lethal.
Collapse
Affiliation(s)
- Devon M Keeler
- UNCW Center for Marine Science, 5600 Marvin K Moss Lane, Wilmington, NC 28409, USA.
| | - Meghan K Grandal
- UNCW Center for Marine Science, 5600 Marvin K Moss Lane, Wilmington, NC 28409, USA.
| | - Jennifer R McCall
- UNCW Center for Marine Science, 5600 Marvin K Moss Lane, Wilmington, NC 28409, USA.
| |
Collapse
|
4
|
Immune effects of the neurotoxins ciguatoxins and brevetoxins. Toxicon 2018; 149:6-19. [PMID: 29360534 DOI: 10.1016/j.toxicon.2018.01.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/27/2017] [Accepted: 01/04/2018] [Indexed: 11/21/2022]
Abstract
Ciguatoxins (CTXs) and brevetoxins (PbTxs) are phycotoxins that can accumulate along the marine food chain and thus cause seafood poisoning in humans, namely "ciguatera fish poisoning" (CFP) and "neurotoxic shellfish poisoning" (NSP), respectively. CFP is characterized by early gastrointestinal symptoms and typical sensory disorders (paraesthesia, pain, pruritus and cold dysaesthesia), which can persist several weeks and, in some cases, several months or years. NSP is considered a mild form of CFP with similar but less severe symptoms. After inhaled exposure, PbTxs can also cause respiratory tract irritation in healthy subjects and asthma exacerbations in predisposed subjects, whose respiratory functions may be disrupted for several days following PbTx inhalation. Mechanistically, it is well established that CTX- or PbTx-induced disturbances are primarily mainly due to voltage-gated sodium channel activation in sensory and motor peripheral nervous system. However, little is known about the pathophysiology or a potential individual susceptibility to long lasting effects of CFP/NSP. In addition to their action on the nervous system, PbTxs and CTXs were also shown to exert effects on the immune system. However, their role in the pathophysiology of syndromes induced by CTX or PbTx exposure is poorly documented. The aim of this review is to inventory the literature thus far on the inflammatory and immune effects of PbTxs and CTXs.
Collapse
|
5
|
Cocilova CC, Flewelling LJ, Bossart GD, Granholm AA, Milton SL. Tissue uptake, distribution and excretion of brevetoxin-3 after oral and intratracheal exposure in the freshwater turtle Trachemys scripta and the diamondback terrapin Malaclemys terrapin. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2017; 187:29-37. [PMID: 28363127 DOI: 10.1016/j.aquatox.2017.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/27/2017] [Accepted: 03/01/2017] [Indexed: 06/07/2023]
Abstract
Harmful algal blooms (HABs) occur nearly annually off the west coast of Florida and can impact both humans and wildlife, resulting in morbidity and increased mortality of marine animals including sea turtles. The key organism in Florida red tides is the dinoflagellate Karenia brevis that produces a suite of potent neurotoxins referred to as the brevetoxins (PbTx). Despite recent mortality events and rehabilitation efforts, still little is known about how the toxin directly impacts sea turtles, as they are not amenable to experimentation and what is known about toxin levels and distribution comes primarily from post-mortem data. In this study, we utilized the freshwater turtle Trachemys scripta and the diamondback terrapin, Malaclemys terrapin as model organisms to determine the distribution, clearance, and routes of excretion of the most common form of the toxin, brevetoxin-3, in turtles. Turtles were administered toxin via esophageal tube to mimic ingestion (33.48μg/kg PbTx-3, 3×/week for two weeks for a total of 7 doses) or by intratracheal instillation (10.53μg/kg, 3×/week for four weeks for a total of 12 doses) to mimic inhalation. Both oral and intratracheal administration of the toxin produced a suite of behavioral responses symptomatic of brevetoxicosis. The toxin distributed to all organ systems within 1h of administration but was rapidly cleared out over 24-48h, corresponding to a decline in clinical symptoms. Excretion appears to be primarily through conjugation to bile salts. Histopathological study revealed that the frequency of lesions varied within experimental groups with some turtles having no significant lesions at all, while similar lesions were found in a low number of control turtles suggesting another common factor(s) could be responsible. The overall goal of this research is better understand the impacts of brevetoxin on turtles in order to develop better treatment protocols for sea turtles exposed to HABs.
Collapse
Affiliation(s)
- Courtney C Cocilova
- Florida Atlantic University, Department of Biological Sciences, 777 Glades Road, Boca Raton, FL 33431, USA.
| | - Leanne J Flewelling
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, 100 8th Avenue S.E., St. Petersburg, FL 33701, USA
| | - Gregory D Bossart
- Animal Health, Research and Conservation, Georgia Aquarium, 225 Baker St. NW, Atlanta, GA 30313, USA
| | - April A Granholm
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, 100 8th Avenue S.E., St. Petersburg, FL 33701, USA
| | - Sarah L Milton
- Florida Atlantic University, Department of Biological Sciences, 777 Glades Road, Boca Raton, FL 33431, USA
| |
Collapse
|
6
|
Cocilova CC, Milton SL. Characterization of brevetoxin (PbTx-3) exposure in neurons of the anoxia-tolerant freshwater turtle (Trachemys scripta). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 180:115-122. [PMID: 27697698 DOI: 10.1016/j.aquatox.2016.09.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/22/2016] [Accepted: 09/26/2016] [Indexed: 06/06/2023]
Abstract
Harmful algal blooms are increasing in frequency and extent worldwide and occur nearly annually off the west coast of Florida where they affect both humans and wildlife. The dinoflagellate Karenia brevis is a key organism in Florida red tides that produces a suite of potent neurotoxins collectively referred to as the brevetoxins (PbTx). Brevetoxins bind to and open voltage gated sodium channels (VGSC), increasing cell permeability in excitable cells and depolarizing nerve and muscle tissue. Exposed animals may thus show muscular and neurological symptoms including head bobbing, muscle twitching, paralysis, and coma; large HABs can result in significant morbidity and mortality of marine life, including fish, birds, marine mammals, and sea turtles. Brevetoxicosis however is difficult to treat in endangered sea turtles as the physiological impacts have not been investigated and the magnitude and duration of brevetoxin exposure are generally unknown. In this study we used the freshwater turtle Trachemys scripta as a model organism to investigate the effects of the specific brevetoxin PbTx-3 in the turtle brain. Primary turtle neuronal cell cultures were exposed to a range of PbTx-3 concentrations to determine excitotoxicity. Agonists and antagonists of voltage-gated sodium channels and downstream targets were utilized to confirm the toxin's mode of action. We found that turtle neurons are highly resistant to PbTx-3; while cell viability decreased in a dose dependent manner across PbTx-3 concentrations of 100-2000nM, the EC50 was significantly higher than has been reported in mammalian neurons. PbTx-3 exposure resulted in significant Ca2+ influx, which could be fully abrogated by the VGSC antagonist tetrodotoxin, NMDA receptor blocker MK-801, and tetanus toxin, indicating that the mode of action in turtle neurons is the same as in mammalian cells. As both turtle and mammalian VGSCs have a high affinity for PbTx-3, we suggest that the high resistance of the turtle neuron to PbTx-3 may be related to its ability to withstand anoxic depolarization. The ultimate goal of this work is to design treatment protocols for sea turtles exposed to red tides worldwide.
Collapse
Affiliation(s)
- Courtney C Cocilova
- Florida Atlantic University, Department of Biological Sciences, 777 Glades Road, Boca Raton, FL, 33431, USA.
| | - Sarah L Milton
- Florida Atlantic University, Department of Biological Sciences, 777 Glades Road, Boca Raton, FL, 33431, USA
| |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
McCall JR, Goodman AJ, Jacocks HM, Thompson A, Baden DG, Bourdelais AJ. Development of a fluorescence assay for the characterization of brevenal binding to rat brain synaptosomes. JOURNAL OF NATURAL PRODUCTS 2014; 77:2014-20. [PMID: 25226846 PMCID: PMC4176390 DOI: 10.1021/np500118p] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Indexed: 06/03/2023]
Abstract
The marine dinoflagellate Karenia brevis produces a family of neurotoxins known as brevetoxins. Brevetoxins elicit their effects by binding to and activating voltage-sensitive sodium channels (VSSCs) in cell membranes. K. brevis also produces brevenal, a brevetoxin antagonist, which is able to inhibit and/or negate many of the detrimental effects of brevetoxins. Brevenal binding to VSSCs has yet to be fully characterized, in part due to the difficulty and expense of current techniques. In this study, we have developed a novel fluorescence binding assay for the brevenal binding site. Several fluorescent compounds were conjugated to brevenal to assess their effects on brevenal binding. The assay was validated against the radioligand assay for the brevenal binding site and yielded comparable equilibrium inhibition constants. The fluorescence-based assay was shown to be quicker and far less expensive and did not generate radioactive waste or need facilities for handling radioactive materials. In-depth studies using the brevenal conjugates showed that, while brevenal conjugates do bind to a binding site in the VSSC protein complex, they are not displaced by known VSSC site specific ligands. As such, brevenal elicits its action through a novel mechanism and/or currently unknown receptor site on VSSCs.
Collapse
Affiliation(s)
- Jennifer R. McCall
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
| | - Allan J. Goodman
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
| | - Henry M. Jacocks
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
| | - Alysha
M. Thompson
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
| | - Daniel G. Baden
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
| | - Andrea J. Bourdelais
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
| |
Collapse
|
9
|
Munday R, Reeve J. Risk assessment of shellfish toxins. Toxins (Basel) 2013; 5:2109-37. [PMID: 24226039 PMCID: PMC3847717 DOI: 10.3390/toxins5112109] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 10/23/2013] [Accepted: 10/30/2013] [Indexed: 01/24/2023] Open
Abstract
Complex secondary metabolites, some of which are highly toxic to mammals, are produced by many marine organisms. Some of these organisms are important food sources for marine animals and, when ingested, the toxins that they produce may be absorbed and stored in the tissues of the predators, which then become toxic to animals higher up the food chain. This is a particular problem with shellfish, and many cases of poisoning are reported in shellfish consumers each year. At present, there is no practicable means of preventing uptake of the toxins by shellfish or of removing them after harvesting. Assessment of the risk posed by such toxins is therefore required in order to determine levels that are unlikely to cause adverse effects in humans and to permit the establishment of regulatory limits in shellfish for human consumption. In the present review, the basic principles of risk assessment are described, and the progress made toward robust risk assessment of seafood toxins is discussed. While good progress has been made, it is clear that further toxicological studies are required before this goal is fully achieved.
Collapse
Affiliation(s)
- Rex Munday
- AgResearch Ltd, Ruakura Research Centre, Private Bag 3123, Hamilton, New Zealand
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +64-7-838-5138; Fax: +64-7-838-5012
| | - John Reeve
- Ministry of Primary Industries, PO Box 2526, Wellington, New Zealand; E-Mail:
| |
Collapse
|
10
|
Mat AM, Haberkorn H, Bourdineaud JP, Massabuau JC, Tran D. Genetic and genotoxic impacts in the oyster Crassostrea gigas exposed to the harmful alga Alexandrium minutum. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 140-141:458-465. [PMID: 23933679 DOI: 10.1016/j.aquatox.2013.07.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/10/2013] [Accepted: 07/15/2013] [Indexed: 06/02/2023]
Abstract
Genotoxic, genetic and behavioral impacts of the paralytic shellfish toxin (PST)-producing alga Alexandrium minutum on the oyster Crassostrea gigas were assessed using RAPD-PCR, qPCR and valve activity recording. Oysters were exposed to a dose mimicking an algal bloom (≈1600 cells ml(-1)) for 48 h. Results indicate a rapid and sustained behavioral disturbance. Animals remained open but exhibited reduced valve-opening amplitude, correlated to the amount of toxin accumulated in the digestive gland. They also exhibited increased micro-closures. In the gills, gene transcription levels were modified: a transcriptional repression of genes involved in oxidative and mitochondrial metabolism, endogenous clock, immunity and detoxification processes was observed. DNA impacts, both quantitative and qualitative, were observed as well. Indeed, both the PCR product profile and the number of hybridization sites for the RAPD probe OPB7 were modified. These results indicate genotoxic effects and gene repression in C. gigas following behavioral disturbance by A. minutum.
Collapse
Affiliation(s)
- Audrey M Mat
- Univ. Bordeaux, EPOC, UMR 5805, F-33120 Arcachon, France
| | | | | | | | | |
Collapse
|
11
|
Kirkland D, Reeve L, Gatehouse D, Vanparys P. A core in vitro genotoxicity battery comprising the Ames test plus the in vitro micronucleus test is sufficient to detect rodent carcinogens and in vivo genotoxins. Mutat Res 2011; 721:27-73. [PMID: 21238603 DOI: 10.1016/j.mrgentox.2010.12.015] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 11/12/2010] [Accepted: 12/15/2010] [Indexed: 01/27/2023]
Abstract
In vitro genotoxicity testing needs to include tests in both bacterial and mammalian cells, and be able to detect gene mutations, chromosomal damage and aneuploidy. This may be achieved by a combination of the Ames test (detects gene mutations) and the in vitro micronucleus test (MNvit), since the latter detects both chromosomal aberrations and aneuploidy. In this paper we therefore present an analysis of an existing database of rodent carcinogens and a new database of in vivo genotoxins in terms of the in vitro genotoxicity tests needed to detect their in vivo activity. Published in vitro data from at least one test system (most were from the Ames test) were available for 557 carcinogens and 405 in vivo genotoxins. Because there are fewer publications on the MNvit than for other mammalian cell tests, and because the concordance between the MNvit and the in vitro chromosomal aberration (CAvit) test is so high for clastogenic activity, positive results in the CAvit test were taken as indicative of a positive result in the MNvit where there were no, or only inadequate data for the latter. Also, because Hprt and Tk loci both detect gene-mutation activity, a positive Hprt test was taken as indicative of a mouse-lymphoma Tk assay (MLA)-positive, where there were no data for the latter. Almost all of the 962 rodent carcinogens and in vivo genotoxins were detected by an in vitro battery comprising Ames+MNvit. An additional 11 carcinogens and six in vivo genotoxins would apparently be detected by the MLA, but many of these had not been tested in the MNvit or CAvit tests. Only four chemicals emerge as potentially being more readily detected in MLA than in Ames+MNvit--benzyl acetate, toluene, morphine and thiabendazole--and none of these are convincing cases to argue for the inclusion of the MLA in addition to Ames+MNvit. Thus, there is no convincing evidence that any genotoxic rodent carcinogens or in vivo genotoxins would remain undetected in an in vitro test battery consisting of Ames+MNvit.
Collapse
Affiliation(s)
- David Kirkland
- Kirkland Consulting, PO Box 79, Tadcaster LS24 0AS, United Kingdom.
| | | | | | | |
Collapse
|
12
|
Fleming LE, Kirkpatrick B, Backer LC, Walsh CJ, Nierenberg K, Clark J, Reich A, Hollenbeck J, Benson J, Cheng YS, Naar J, Pierce R, Bourdelais AJ, Abraham WM, Kirkpatrick G, Zaias J, Wanner A, Mendes E, Shalat S, Hoagland P, Stephan W, Bean J, Watkins S, Clarke T, Byrne M, Baden DG. Review of Florida Red Tide and Human Health Effects. HARMFUL ALGAE 2011; 10:224-233. [PMID: 21218152 PMCID: PMC3014608 DOI: 10.1016/j.hal.2010.08.006] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
This paper reviews the literature describing research performed over the past decade on the known and possible exposures and human health effects associated with Florida red tides. These harmful algal blooms are caused by the dinoflagellate, Karenia brevis, and similar organisms, all of which produce a suite of natural toxins known as brevetoxins. Florida red tide research has benefited from a consistently funded, long term research program, that has allowed an interdisciplinary team of researchers to focus their attention on this specific environmental issue-one that is critically important to Gulf of Mexico and other coastal communities. This long-term interdisciplinary approach has allowed the team to engage the local community, identify measures to protect public health, take emerging technologies into the field, forge advances in natural products chemistry, and develop a valuable pharmaceutical product. The Review includes a brief discussion of the Florida red tide organisms and their toxins, and then focuses on the effects of these toxins on animals and humans, including how these effects predict what we might expect to see in exposed people.
Collapse
Affiliation(s)
- Lora E Fleming
- NSF NIEHS Oceans and Human Health Center, University of Miami, 4600 Rickenbacker Causeway, Miami, FL, 33149
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
|
14
|
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.
Collapse
|
15
|
Brevetoxin B is a clastogen in rats, but lacks mutagenic potential in the SP-98/100 Ames test. Toxicon 2009; 54:851-6. [DOI: 10.1016/j.toxicon.2009.06.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 06/12/2009] [Accepted: 06/16/2009] [Indexed: 11/18/2022]
|
16
|
Murrell RN, Gibson JE. Brevetoxins 2, 3, 6, and 9 show variability in potency and cause significant induction of DNA damage and apoptosis in Jurkat E6-1 cells. Arch Toxicol 2009; 83:1009-19. [PMID: 19536525 DOI: 10.1007/s00204-009-0443-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 06/03/2009] [Indexed: 11/27/2022]
Abstract
Brevetoxins (PbTx) are potent lipid soluble polyether neurotoxins produced by the marine dinoflagellate Karenia brevis, an organism linked to periodic red tide blooms. Brevetoxins exert their toxicity by interacting with neurotoxin receptor site five associated with domain IV of the alpha subunit of the voltage gated sodium channel. Brevetoxin binding to tissues that contain voltage gated sodium channels on excitable cells results in membrane depolarization, repetitive firing, and increase in sodium currents. Brevetoxins have been linked to deaths in marine mammals, which are exposed through ingestion of organisms harboring high brevetoxin concentrations and through the inhalation of aerosolized brevetoxins. Humans are also at risk, primarily through respiratory exposure which can result in a severe inflammatory response. The purpose of this study was to determine the effect of four brevetoxins on Jurkat E6-1 cell proliferation, to assess their variability in potency, genotoxicity, and to determine if brevetoxin causes cell death, specifically through an apoptotic or necrotic mechanism. PbTx 2, 3, 6, and 9 were tested at concentrations of 10(-4)-10(-12) M to determine the IC(50) values and effect on cell proliferation. The IC(50) concentration was then used in the single cell gel electrophoresis assay to determine genotoxicity. The ability to induce apoptosis was then assessed with the Vybrant apoptosis assay, caspase activation assays and PARP cleavage. Results from the cellular proliferation assays demonstrated that high doses of PbTxs inhibit the ability of Jurkat cells to proliferate while lower doses caused an increase in proliferation and that PbTx2 is the most cytotoxic brevetoxin followed by brevetoxins 6, 3, and 9. Brevetoxins 2, 3, and 6 all caused significant DNA damage. A 4 h exposure to brevetoxins 2, 3, 6, and 9 at values close to the IC(50) values resulted in apoptosis positive staining in Jurkat E6-1 cells. High doses of brevetoxins 2 and 6 resulted in activation of caspases 3/7 and 8 and cleavage of poly (ADP-ribose) polymerase (PARP). The conclusions are that brevetoxins affect cell proliferation in a dose-dependent fashion, are genotoxic, and cause cell death through an apoptotic mechanism.
Collapse
Affiliation(s)
- Rachel N Murrell
- Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC, 27695-7633, USA.
| | | |
Collapse
|
17
|
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.
Collapse
|
18
|
Pariera Dinkins CL, Peterson RK, Gibson JE, Hu Q, Weaver DK. Glycoalkaloid responses of potato to Colorado potato beetle defoliation. Food Chem Toxicol 2008; 46:2832-6. [DOI: 10.1016/j.fct.2008.05.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 03/14/2008] [Accepted: 05/21/2008] [Indexed: 11/24/2022]
|
19
|
Radwan FF, Ramsdell JS. Brevetoxin forms covalent DNA adducts in rat lung following intratracheal exposure. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:930-6. [PMID: 18629316 PMCID: PMC2453162 DOI: 10.1289/ehp.11068] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 03/21/2008] [Indexed: 05/07/2023]
Abstract
BACKGROUND Human exposure to brevetoxins produced by the red tide organism, Karenia brevis, is an increasing public health concern. Using in vitro exposure of rat liver cells to brevetoxin B (PbTx-2), the primary toxin product of K. brevis, we previously showed that it formed C(27,28)-epoxy brevetoxin metabolites capable of covalently binding to nucleic acids, a common initiation step for carcinogenesis. OBJECTIVE This study was undertaken to evaluate nucleic acid adduction in lung following in vitro and in vivo brevetoxin exposures. METHODS To clarify reactions of brevetoxin epoxide with DNA, we analyzed reaction products of PbTx-6 (a C(27,28) epoxide metabolite of brevetoxin B) with nucleosides. We also analyzed adducts from nucleic acid hydrolysates of isolated rat lung cells treated with PbTx-2 or PbTx-6 in vitro and lung tissue from rats after intratracheal exposure to PbTx-2 or PbTx-6 at 45 microg toxin/kg body weight. RESULTS Our results indicate that PbTx-2 forms DNA adducts with cytidine after treatment of isolated lung cells, and forms DNA adducts with adenosine and guanosine after intratracheal exposure. CONCLUSIONS These results are consistent with metabolic activation of highly reactive brevetoxin intermediates that bind to nucleic acid. These findings provide a basis for monitoring exposure and assessing the hazard associated with depurination of brevetoxin-nucleotide adducts in lung tissue.
Collapse
Affiliation(s)
- Faisal F.Y. Radwan
- Marine Biotoxins Program, Center for Coastal Environmental Health and Biomolecular Research, National Oceanic and Atmospheric Administration/National Ocean Service, Charleston, South Carolina, USA
- Sohag University, Faculty of Science, Sohag, Egypt
| | - John S. Ramsdell
- Marine Biotoxins Program, Center for Coastal Environmental Health and Biomolecular Research, National Oceanic and Atmospheric Administration/National Ocean Service, Charleston, South Carolina, USA
- Address correspondence to J.S. Ramsdell, Harmful Algal Bloom & Analytical Response Branch, NOAA, 219 Fort Johnson Rd., Charleston, SC 29412, USA. Telephone: (843) 762–8510. Fax: (843) 762–8700. E-mail:
| |
Collapse
|
20
|
Effects of in vitro brevetoxin exposure on apoptosis and cellular metabolism in a leukemic T cell line (Jurkat). Mar Drugs 2008; 6:291-307. [PMID: 18728729 PMCID: PMC2525491 DOI: 10.3390/md20080014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Revised: 05/27/2008] [Accepted: 06/04/2008] [Indexed: 12/25/2022] Open
Abstract
Harmful algal blooms (HABs) of the toxic dinoflagellate, Karenia brevis, produce red tide toxins, or brevetoxins. Significant health effects associated with red tide toxin exposure have been reported in sea life and in humans, with brevetoxins documented within immune cells from many species. The objective of this research was to investigate potential immunotoxic effects of brevetoxins using a leukemic T cell line (Jurkat) as an in vitro model system. Viability, cell proliferation, and apoptosis assays were conducted using brevetoxin congeners PbTx-2, PbTx-3, and PbTx-6. The effects of in vitro brevetoxin exposure on cell viability and cellular metabolism or proliferation were determined using trypan blue and MTT (1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan), respectively. Using MTT, cellular metabolic activity was decreased in Jurkat cells exposed to 5 - 10 microg/ml PbTx-2 or PbTx-6. After 3 h, no significant effects on cell viability were observed with any toxin congener in concentrations up to 10 microg/ml. Viability decreased dramatically after 24 h in cells treated with PbTx-2 or -6. Apoptosis, as measured by caspase-3 activity, was significantly increased in cells exposed to PbTx-2 or PbTx-6. In summary, brevetoxin congeners varied in effects on Jurkat cells, with PbTx-2 and PbTx-6 eliciting greater cellular effects compared to PbTx-3.
Collapse
|
21
|
Effects of in vitro Brevetoxin Exposure on Apoptosis and Cellular Metabolism in a Leukemic T Cell Line (Jurkat). Mar Drugs 2008. [DOI: 10.3390/md6020291] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|