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Robinson KE, Moniz HA, Stokes AN, Feldman CR. Where Does All the Poison Go? Investigating Toxicokinetics of Newt (Taricha) Tetrodotoxin (TTX) in Garter Snakes (Thamnophis). J Chem Ecol 2024:10.1007/s10886-024-01517-7. [PMID: 38842636 DOI: 10.1007/s10886-024-01517-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 05/14/2024] [Accepted: 05/22/2024] [Indexed: 06/07/2024]
Abstract
Animals that consume toxic diets provide models for understanding the molecular and physiological adaptations to ecological challenges. Garter snakes (Thamnophis) in western North America prey on Pacific newts (Taricha), which employ tetrodotoxin (TTX) as an antipredator defense. These snakes possess mutations in voltage-gated sodium channels (Nav), the molecular targets of TTX, that decrease the binding ability of TTX to sodium channels (target-site resistance). However, genetic variation at these loci that cannot explain all the phenotypic variation in TTX resistance in Thamnophis. We explored a separate means of resistance, toxin metabolism, to determine if TTX-resistant snakes either rapidly remove TTX or sequester TTX. We examined the metabolism and distribution of TTX in the body (toxicokinetics), to determine differences between TTX-resistant and TTX-sensitive snakes in the rates at which TTX is eliminated from organs and the whole body (using TTX half-life as our metric). We assayed TTX half-life in snakes from TTX-resistant and TTX-sensitive populations of three garter snake species with a coevolutionary history with newts (T. atratus, T. couchii, T. sirtalis), as well as two non-resistant "outgroup" species (T. elegans, Pituophis catenifer) that seldom (if ever) engage newts. We found TTX half-life varied across species, populations, and tissues. Interestingly, TTX half-life was shortest in T. elegans and P. catenifer compared to all other snakes. Furthermore, TTX-resistant populations of T. couchii and T. sirtalis eliminated TTX faster (shorter TTX half-life) than their TTX-sensitive counterparts, while populations of TTX-resistant and TTX-sensitive T. atratus showed no difference rates of TTX removal (same TTX half-life). The ability to rapidly eliminate TTX may have permitted increased prey consumption, which may have promoted the evolution of additional resistance mechanisms. Finally, snakes still retain substantial amounts of TTX, and we projected that snakes could be dangerous to their own predators days to weeks following the ingestion of a single newt. Thus, aspects of toxin metabolism may have been key in driving predator-prey relationships, and important in determining other ecological interactions.
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Affiliation(s)
- Kelly E Robinson
- Department of Biology and Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, NV, USA.
- Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA.
| | - Haley A Moniz
- Department of Biology and Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, NV, USA
- Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA, USA
| | - Amber N Stokes
- Department of Biology, California State University Bakersfield, Bakersfield, CA, USA
| | - Chris R Feldman
- Department of Biology and Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, NV, USA
- Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA
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2
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Melnikova DI, Magarlamov TY. An Overview of the Anatomical Distribution of Tetrodotoxin in Animals. Toxins (Basel) 2022; 14:toxins14080576. [PMID: 36006238 PMCID: PMC9412668 DOI: 10.3390/toxins14080576] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/15/2022] [Accepted: 08/19/2022] [Indexed: 11/23/2022] Open
Abstract
Tetrodotoxin (TTX), a potent paralytic sodium channel blocker, is an intriguing marine toxin. Widely distributed in nature, TTX has attracted attention in various scientific fields, from biomedical studies to environmental safety concerns. Despite a long history of studies, many issues concerning the biosynthesis, origin, and spread of TTX in animals and ecosystems remain. This review aims to summarize the current knowledge on TTX circulation inside TTX-bearing animal bodies. We focus on the advances in TTX detection at the cellular and subcellular levels, providing an expanded picture of intra-organismal TTX migration mechanisms. We believe that this review will help address the gaps in the understanding of the biological function of TTX and facilitate the development of further studies involving TTX-bearing animals.
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3
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Hanifin CT, Kudo Y, Yotsu-Yamashita M. Chemical Ecology of the North American Newt Genera Taricha and Notophthalmus. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2022; 118:101-130. [PMID: 35416518 DOI: 10.1007/978-3-030-92030-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The North American newt genera Taricha and Notophthalmus (order Caudata) are well known for the combination of potent toxicity, aposematic coloration, and striking defense postures that protects these animals from predation. This suite of traits is centered around the neurotoxin tetrodotoxin, which causes paralysis and death in metazoans by disrupting the initiation and propagation of electrical signals in the nerves and muscles. Tetrodotoxin defends newts from predation across multiple life history stages and its role in generating arms-race coevolution between Taricha newts and garter snake (genus Thamnophis) predators is well studied. However, understanding the broader picture of chemical defenses in Taricha and Notophthalmus requires an expanded comprehension of the defensive chemical ecology of tetrodotoxin that includes possible coevolutionary interactions with insect egg predators, protection against parasites, as well as mimicry complexes associated with tetrodotoxin and aposematic coloration in both genera. Herein the authors review what is known about the structure, function, and pharmacology of tetrodotoxin to explore its evolution and chemical ecology in the North American newt. Focus is made specifically on the origin and possible biosynthesis of tetrodotoxin in these taxa as well as providing an expanded picture of the web of interactions that contribute to landscape level patterns of toxicity and defense in Taricha and Notophthalmus.
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Affiliation(s)
- Charles T Hanifin
- Department of Biology, Utah State University, 320 N. Aggie Blvd, Vernal, UT, 84078, USA.
| | - Yuta Kudo
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science & Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan
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4
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Robinson KE, Holding ML, Whitford MD, Saviola AJ, Yates JR, Clark RW. Phenotypic and functional variation in venom and venom resistance of two sympatric rattlesnakes and their prey. J Evol Biol 2021; 34:1447-1465. [PMID: 34322920 DOI: 10.1111/jeb.13907] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/27/2021] [Accepted: 07/13/2021] [Indexed: 12/15/2022]
Abstract
Predator-prey interactions often lead to the coevolution of adaptations associated with avoiding predation and, for predators, overcoming those defences. Antagonistic coevolutionary relationships are often not simple interactions between a single predator and prey but rather a complex web of interactions between multiple coexisting species. Coevolution between venomous rattlesnakes and small mammals has led to physiological venom resistance in several mammalian taxa. In general, viperid venoms contain large quantities of snake venom metalloproteinase toxins (SVMPs), which are inactivated by SVMP inhibitors expressed in resistant mammals. We explored variation in venom chemistry, SVMP expression, and SVMP resistance across four co-distributed species (California Ground Squirrels, Bryant's Woodrats, Southern Pacific Rattlesnakes, and Red Diamond Rattlesnakes) collected from four different populations in Southern California. Our aim was to understand phenotypic and functional variation in venom and venom resistance in order to compare coevolutionary dynamics of a system involving two sympatric predator-prey pairs to past studies that have focused on single pairs. Proteomic analysis of venoms indicated that these rattlesnakes express different phenotypes when in sympatry, with Red Diamonds expressing more typical viperid venom (with a diversity of SVMPs) and Southern Pacifics expressing a more atypical venom with a broader range of non-enzymatic toxins. We also found that although blood sera from both mammals were generally able to inhibit SVMPs from both rattlesnake species, inhibition depended strongly on the snake population, with snakes from one geographic site expressing SVMPs to which few mammals were resistant. Additionally, we found that Red Diamond venom, rather than woodrat resistance, was locally adapted. Our findings highlight the complexity of coevolutionary relationships between multiple predators and prey that exhibit similar offensive and defensive strategies in sympatry.
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Affiliation(s)
- Kelly E Robinson
- Department of Biology, San Diego State University, San Diego, CA, USA.,Department of Biology, University of Nevada, Reno, NV, USA.,Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA
| | - Matthew L Holding
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV, USA.,Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Malachi D Whitford
- Department of Biology, San Diego State University, San Diego, CA, USA.,Ecology Graduate Group, University of California, Davis, CA, USA
| | - Anthony J Saviola
- Department of Molecular Medicine and Neurobiology, The Scripps Research Institute, La Jolla, CA, USA.,Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - John R Yates
- Department of Molecular Medicine and Neurobiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Rulon W Clark
- Department of Biology, San Diego State University, San Diego, CA, USA
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5
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Convergent and parallel evolution in a voltage-gated sodium channel underlies TTX-resistance in the Greater Blue-ringed Octopus: Hapalochlaena lunulata. Toxicon 2019; 170:77-84. [DOI: 10.1016/j.toxicon.2019.09.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 12/24/2022]
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6
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Calhoun DM, Bucciarelli GM, Kats LB, Zimmer RK, Johnson PTJ. Noxious newts and their natural enemies: Experimental effects of tetrodotoxin exposure on trematode parasites and aquatic macroinvertebrates. Toxicon 2017; 137:120-127. [PMID: 28755852 PMCID: PMC5578716 DOI: 10.1016/j.toxicon.2017.07.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/21/2017] [Accepted: 07/23/2017] [Indexed: 01/04/2023]
Abstract
The dermal glands of many amphibian species secrete toxins or other noxious substances as a defense strategy against natural enemies. Newts in particular possess the potent neurotoxin tetrodotoxin (TTX), for which the highest concentrations are found in species within the genus Taricha. Adult Taricha are hypothesized to use TTX as a chemical defense against vertebrate predators such as garter snakes (Thamnophis spp.). However, less is known about how TTX functions to defend aquatic-developing newt larvae against natural enemies, including trematode parasites and aquatic macroinvertebrates. Here we experimentally investigated the effects of exogenous TTX exposure on survivorship of the infectious stages (cercariae) of five species of trematode parasites that infect larval amphibians. Specifically, we used dose-response curves to test the sensitivity of trematode cercariae to progressively increasing concentrations of TTX (0.0 [control], 0.63, 3.13, 6.26, 31.32, and 62.64 nmol L-1) and how this differed among parasite species. We further compared these results to the effects of TTX exposure (0 and 1000 nmolL-1) over 24 h on seven macroinvertebrate taxa commonly found in aquatic habitats with newt larvae. TTX significantly reduced the survivorship of trematode cercariae for all species, but the magnitude of such effects varied among species. Ribeiroia ondatrae - which causes mortality and limb malformations in amphibians - was the least sensitive to TTX, whereas the kidney-encysting Echinostoma trivolvis was the most sensitive. Among the macroinvertebrate taxa, only mayflies (Ephemeroptera) showed a significant increase in mortality following exogenous TTX exposure, despite the use of a concentration 16x higher than the maximum used for trematodes. Our results suggest that maternal investment of TTX into larval newts may provide protection against certain trematode infections and highlight the importance of future work assessing the effects of newt toxicity on both parasite infection success and the palatability of larval newts to invertebrate predators.
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Affiliation(s)
- Dana M Calhoun
- University of Colorado Boulder, Department of Ecology and Evolutionary Biology, Ramaley N122, CB334, Boulder, CO 80309, USA.
| | - Gary M Bucciarelli
- University of California, Los Angeles, Department of Ecology and Evolutionary Biology, 610 Charles E. Young Dr. East, Los Angeles, CA 90095, USA; University of California, Los Angeles, La Kretz Center for California Conservation Science, Institute of the Environmental Sustainability, La Kretz Hall, Los Angeles, CA 90095, USA.
| | - Lee B Kats
- Pepperdine University, Natural Science Division Pacific Coast Highway, Malibu, CA 90263, USA.
| | - Richard K Zimmer
- University of California, Los Angeles, Department of Ecology and Evolutionary Biology, 610 Charles E. Young Dr. East, Los Angeles, CA 90095, USA; University of Queensland, Moreton Bay Research Station, Centre for Marine Sciences, School of Biological Sciences, Dunwich, Queensland 4183, Australia.
| | - Pieter T J Johnson
- University of Colorado Boulder, Department of Ecology and Evolutionary Biology, Ramaley N122, CB334, Boulder, CO 80309, USA.
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Kudo Y, Chiba C, Konoki K, Cho Y, Yotsu-Yamashita M. Dietary administration of tetrodotoxin and its putative biosynthetic intermediates to the captive-reared non-toxic Japanese fire-bellied newt, Cynops pyrrhogaster. Toxicon 2017; 137:78-82. [DOI: 10.1016/j.toxicon.2017.07.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 07/10/2017] [Accepted: 07/14/2017] [Indexed: 10/19/2022]
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8
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Reverté L, Rambla-Alegre M, Leonardo S, Bellés C, Campbell K, Elliott CT, Gerssen A, Klijnstra MD, Diogène J, Campàs M. Development and validation of a maleimide-based enzyme-linked immunosorbent assay for the detection of tetrodotoxin in oysters and mussels. Talanta 2017; 176:659-666. [PMID: 28917804 DOI: 10.1016/j.talanta.2017.08.058] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/10/2017] [Accepted: 08/11/2017] [Indexed: 11/30/2022]
Abstract
The recent detection of tetrodotoxins (TTXs) in puffer fish and shellfish in Europe highlights the necessity to monitor the levels of TTXs in seafood by rapid, specific, sensitive and reliable methods in order to protect human consumers. A previous immunoassay for TTX detection in puffer fish, based on the use of self-assembled monolayers (SAMs) for the immobilization of TTX on maleimide plates (mELISA), has been modified and adapted to the analysis of oyster and mussel samples. Changing dithiol for cysteamine-based SAMs enabled reductions in the assay time and cost, while maintaining the sensitivity of the assay. The mELISA showed high selectivity for TTX since the antibody did not cross-react with co-occurring paralytic shellfish poisoning (PSP) toxins and no interferences were observed from arginine (Arg). Moreover, TTX-coated maleimide plates stored for 3 months at -20°C and 4°C were stable, thus when pre-prepared, the time to perform the assay is reduced. When analyzing shellfish samples, matrix effects and toxin recovery values strongly depended on the shellfish type and the sample treatment. Blank oyster extracts could be directly analyzed without solid-phase extraction (SPE) clean-up, whereas blank mussel extracts showed strong matrix effects and SPE and subsequent solvent evaporation were required for removal. However, the SPE clean-up and evaporation resulted in toxin loss. Toxin recovery values were taken as correction factors (CFs) and were applied to the quantification of TTX contents in the analysis of naturally-contaminated shellfish samples by mELISA. The lowest effective limits of detection (eLODs) were about 20 and 50µg/kg for oyster extracts without and with SPE clean-up, respectively, and about 30µg/kg for mussel extracts with both protocols, all of them substantially below the eLOD attained in the previous mELISA for puffer fish (230µg/kg). Analysis of naturally-contaminated samples by mELISA and comparison with LC-MS/MS quantifications demonstrated the viability of the approach. This mELISA is a selective and sensitive tool for the rapid detection of TTX in oyster and mussel samples showing promise to be implemented in routine monitoring programs to protect human health.
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Affiliation(s)
- Laia Reverté
- IRTA, Carretera Poble Nou km 5.5, 43540 Sant Carles de la Ràpita, Tarragona, Spain
| | - Maria Rambla-Alegre
- IRTA, Carretera Poble Nou km 5.5, 43540 Sant Carles de la Ràpita, Tarragona, Spain
| | - Sandra Leonardo
- IRTA, Carretera Poble Nou km 5.5, 43540 Sant Carles de la Ràpita, Tarragona, Spain
| | - Carlos Bellés
- IRTA, Carretera Poble Nou km 5.5, 43540 Sant Carles de la Ràpita, Tarragona, Spain
| | - Katrina Campbell
- Institute for Global Food Security, School of Biological Sciences, Queen's University, Stranmillis Road, Belfast BT9 5AG, Northern Ireland, UK
| | - Christopher T Elliott
- Institute for Global Food Security, School of Biological Sciences, Queen's University, Stranmillis Road, Belfast BT9 5AG, Northern Ireland, UK
| | - Arjen Gerssen
- RIKILT (Institute of Food Safety) - Wageningen University and Research, 6700 AE, Wageningen, The Netherlands
| | - Mirjam D Klijnstra
- RIKILT (Institute of Food Safety) - Wageningen University and Research, 6700 AE, Wageningen, The Netherlands
| | - Jorge Diogène
- IRTA, Carretera Poble Nou km 5.5, 43540 Sant Carles de la Ràpita, Tarragona, Spain
| | - Mònica Campàs
- IRTA, Carretera Poble Nou km 5.5, 43540 Sant Carles de la Ràpita, Tarragona, Spain.
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Hague MTJ, Avila LA, Hanifin CT, Snedden WA, Stokes AN, Brodie ED, Brodie ED. Toxicity and population structure of the Rough-Skinned Newt (Taricha granulosa) outside the range of an arms race with resistant predators. Ecol Evol 2016; 6:2714-24. [PMID: 27066249 PMCID: PMC4798830 DOI: 10.1002/ece3.2068] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 02/11/2016] [Accepted: 02/22/2016] [Indexed: 01/07/2023] Open
Abstract
Species interactions, and their fitness consequences, vary across the geographic range of a coevolutionary relationship. This spatial heterogeneity in reciprocal selection is predicted to generate a geographic mosaic of local adaptation, wherein coevolutionary traits are phenotypically variable from one location to the next. Under this framework, allopatric populations should lack variation in coevolutionary traits due to the absence of reciprocal selection. We examine phenotypic variation in tetrodotoxin (TTX) toxicity of the Rough-Skinned Newt (Taricha granulosa) in regions of allopatry with its TTX-resistant predator, the Common Garter Snake (Thamnophis sirtalis). In sympatry, geographic patterns of phenotypic exaggeration in toxicity and toxin-resistance are closely correlated in prey and predator, implying that reciprocal selection drives phenotypic variation in coevolutionary traits. Therefore, in allopatry with TTX-resistant predators, we expect to find uniformly low levels of newt toxicity. We characterized TTX toxicity in northwestern North America, including the Alaskan panhandle where Ta. granulosa occur in allopatry with Th. sirtalis. First, we used microsatellite markers to estimate population genetic structure and determine if any phenotypic variation in toxicity might be explained by historical divergence. We found northern populations of Ta. granulosa generally lacked population structure in a pattern consistent with northern range expansion after the Pleistocene. Next, we chose a cluster of sites in Alaska, which uniformly lacked genetic divergence, to test for phenotypic divergence in toxicity. As predicted, overall levels of newt toxicity were low; however, we also detected unexpected among- and within-population variation in toxicity. Most notably, a small number of individuals contained large doses of TTX that rival means of toxic populations in sympatry with Th. sirtalis. Phenotypic variation in toxicity, despite limited neutral genetic divergence, suggests that factors other than reciprocal selection with Th. sirtalis likely contribute to geographic patterns of toxicity in Ta. granulosa.
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Affiliation(s)
- Michael T J Hague
- Department of Biology University of Virginia Charlottesville Virginia
| | - Leleña A Avila
- Museum of Vertebrate Zoology University of California Berkeley California
| | - Charles T Hanifin
- Department of Biology Utah State University, Uintah Basin Campus Vernal Utah
| | | | - Amber N Stokes
- Department of Biology California State University Bakersfield California
| | | | - Edmund D Brodie
- Department of Biology University of Virginia Charlottesville Virginia
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The praying mantis (Mantodea) as predator of the poisonous red-spotted newt Notophthalmus viridescens (Amphibia: Urodela: Salamandridae). CHEMOECOLOGY 2016. [DOI: 10.1007/s00049-016-0211-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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Berlinck RGS, Romminger S. The chemistry and biology of guanidine natural products. Nat Prod Rep 2016; 33:456-90. [DOI: 10.1039/c5np00108k] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The present review discusses the isolation, structure determination, synthesis, biosynthesis and biological activities of secondary metabolites bearing a guanidine group.
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Affiliation(s)
| | - Stelamar Romminger
- Instituto de Química de São Carlos
- Universidade de São Paulo
- São Carlos
- Brazil
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12
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Wilson N, Stokes A, Hopkins G, Brodie, Jr. E, Williams C. Functional and physiological resistance of crayfish to amphibian toxins: tetrodotoxin resistance in the white river crayfish (Procambarus acutus). CAN J ZOOL 2014. [DOI: 10.1139/cjz-2014-0128] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Freshwater crayfish are reported to consume early life-history stages of a number of toxic amphibians. Although previous research indicates toxic amphibians are palatable to crayfish, the potential toxicity associated with consumption of toxic prey has been poorly described. We sought to characterise the supposed tetrodotoxin (TTX) resistance of freshwater crayfish, which have been observed to eat the eggs and larvae of toxic Taricha Gray, 1850 newts. White river crayfish (Procambarus acutus (Girard, 1852)) consumed 7.7 ± 4.0 Rough-skinned Newt (Taricha granulosa (Skilton, 1849)) eggs (mean ± SD) when offered 10 eggs in controlled feeding trials. Eggs were determined to contain a concentration of 1239 ± 571 ng (mean ± SD) of TTX. A dose-response assay was then performed to compare ingested doses with physiological TTX resistance. Crayfish were highly susceptible to TTX when administered as an intramuscular injection; TTX doses of 0.1 mass-adjusted mouse units were lethal to 100% of P. acutus crayfish. We established that while crayfish were capable consumers of highly toxic newt eggs, these decapods did not demonstrate physiological resistance to TTX. These findings suggest that crayfish have some functional resistance that renders them capable of consuming TTX-bearing prey despite a lack of physiological resistance to TTX.
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Affiliation(s)
- N.J. Wilson
- Sansom Institute for Health Research, University of South Australia, City East Campus, Frome Road, Adelaide, SA 5000, Australia
| | - A.N. Stokes
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA
| | - G.R. Hopkins
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA
| | - E.D. Brodie, Jr.
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA
| | - C.R. Williams
- Sansom Institute for Health Research, University of South Australia, City East Campus, Frome Road, Adelaide, SA 5000, Australia
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Gall BG, Stokes AN, Pett JJ, Spivey KL, French SS, Brodie ED, Brodie ED. Tetrodotoxin concentrations within a clutch and across embryonic development in eggs of the rough-skinned newts (Taricha granulosa). Toxicon 2014; 90:249-54. [DOI: 10.1016/j.toxicon.2014.08.060] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Revised: 08/12/2014] [Accepted: 08/14/2014] [Indexed: 12/24/2022]
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14
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Khor S, Wood SA, Salvitti L, Taylor DI, Adamson J, McNabb P, Cary SC. Investigating diet as the source of tetrodotoxin in Pleurobranchaea maculata. Mar Drugs 2013; 12:1-16. [PMID: 24368566 PMCID: PMC3917257 DOI: 10.3390/md12010001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 11/18/2013] [Accepted: 12/02/2013] [Indexed: 11/18/2022] Open
Abstract
The origin of tetrodotoxin (TTX) is highly debated; researchers have postulated either an endogenous or exogenous source with the host accumulating TTX symbiotically or via food chain transmission. The aim of this study was to determine whether the grey side-gilled sea slug (Pleurobranchaea maculata) could obtain TTX from a dietary source, and to attempt to identify this source through environmental surveys. Eighteen non-toxic P. maculata were maintained in aquariums and twelve were fed a TTX-containing diet. Three P. maculata were harvested after 1 h, 24 h, 17 days and 39 days and TTX concentrations in their stomach, gonad, mantle and remaining tissue/fluids determined using liquid chromatography-mass spectrometry. Tetrodotoxin was detected in all organs/tissue after 1 h with an average uptake of 32%. This decreased throughout the experiment (21%, 15% and 9%, respectively). Benthic surveys at sites with dense populations of toxic P. maculata detected very low or no TTX in other organisms. This study demonstrates that P. maculata can accumulate TTX through their diet. However, based on the absence of an identifiable TTX source in the environment, in concert with the extremely high TTX concentrations and short life spans of P. maculata, it is unlikely to be the sole TTX source for this species.
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Affiliation(s)
- Serena Khor
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand; E-Mails: (S.K.); (L.S.); (S.C.C.)
| | - Susanna A. Wood
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand; E-Mails: (S.K.); (L.S.); (S.C.C.)
- Cawthron Institute, Nelson 7042, New Zealand; E-Mails: (D.I.T.); (J.A.); (P.M.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +64-3-548-2319; Fax: +64-3-546-9464
| | - Lauren Salvitti
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand; E-Mails: (S.K.); (L.S.); (S.C.C.)
| | - David I. Taylor
- Cawthron Institute, Nelson 7042, New Zealand; E-Mails: (D.I.T.); (J.A.); (P.M.)
| | - Janet Adamson
- Cawthron Institute, Nelson 7042, New Zealand; E-Mails: (D.I.T.); (J.A.); (P.M.)
| | - Paul McNabb
- Cawthron Institute, Nelson 7042, New Zealand; E-Mails: (D.I.T.); (J.A.); (P.M.)
- Department of Chemistry, Otago University, Dunedin 9054, New Zealand
| | - Stephen Craig Cary
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand; E-Mails: (S.K.); (L.S.); (S.C.C.)
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