1
|
Caty SN, Alvarez-Buylla A, Vasek C, Tapia EE, Martin NA, McLaughlin T, Weber PK, Mayali X, Coloma LA, Morris MM, O'Connell LA. A toxic environment selects for specialist microbiome in poison frogs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.574901. [PMID: 38260330 PMCID: PMC10802471 DOI: 10.1101/2024.01.10.574901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Shifts in microbiome community composition can have large effects on host health. It is therefore important to understand how perturbations, like those caused by the introduction of exogenous chemicals, modulate microbiome community composition. In poison frogs within the family Dendrobatidae, the skin microbiome is exposed to the alkaloids that the frogs sequester from their diet and use for defense. Given the demonstrated antimicrobial effects of these poison frog alkaloids, these compounds may be structuring the skin microbial community. To test this, we first characterized microbial communities from chemically defended and closely related non-defended frogs from Ecuador. Then we conducted a laboratory experiment to monitor the effect of the alkaloid decahydroquinoline (DHQ) on the microbiome of a single frog species. In both the field and lab experiments, we found that alkaloid-exposed microbiomes are more species rich and phylogenetically diverse, with an increase in rare taxa. To better understand the strain-specific behavior in response to alkaloids, we cultured microbial strains from poison frog skin and found the majority of strains exhibited either enhanced growth or were not impacted by the addition of DHQ. Additionally, stable isotope tracing coupled to nanoSIMS suggests that some of these strains are able to metabolize DHQ. Taken together, these data suggest that poison frog chemical defenses open new niches for skin-associated microbes with specific adaptations, including the likely metabolism of alkaloids, that enable their survival in this toxic environment. This work helps expand our understanding of how exposure to exogenous compounds like alkaloids can impact host microbiomes.
Collapse
Affiliation(s)
| | | | - Cooper Vasek
- Department of Biology, Stanford University, Stanford CA, USA
| | - Elicio E Tapia
- Leibniz Institute for the Analysis of Biodiversity Change Martin-Luther-King-Platz 3 20146 Hamburg, Germany
| | - Nora A Martin
- Department of Biology, Stanford University, Stanford CA, USA
| | - Theresa McLaughlin
- Stanford University Mass Spectrometry, Stanford University, Stanford CA, USA
| | - Peter K Weber
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore CA, USA
| | - Xavier Mayali
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore CA, USA
| | - Luis A Coloma
- Centro Jambatu de Investigación y Conservación de Anfibios, Fundación Jambatu, San Rafael, Quito, Ecuador
| | - Megan M Morris
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore CA, USA
| | - Lauren A O'Connell
- Department of Biology, Stanford University, Stanford CA, USA
- Sarafan ChEM-H, Stanford University, Stanford, CA, USA
| |
Collapse
|
2
|
Alvarez-Buylla A, Fischer MT, Moya Garzon MD, Rangel AE, Tapia EE, Tanzo JT, Soh HT, Coloma LA, Long JZ, O'Connell LA. Binding and sequestration of poison frog alkaloids by a plasma globulin. eLife 2023; 12:e85096. [PMID: 38206862 PMCID: PMC10783871 DOI: 10.7554/elife.85096] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 12/07/2023] [Indexed: 01/13/2024] Open
Abstract
Alkaloids are important bioactive molecules throughout the natural world, and in many animals they serve as a source of chemical defense against predation. Dendrobatid poison frogs bioaccumulate alkaloids from their diet to make themselves toxic or unpalatable to predators. Despite the proposed roles of plasma proteins as mediators of alkaloid trafficking and bioavailability, the responsible proteins have not been identified. We use chemical approaches to show that a ~50 kDa plasma protein is the principal alkaloid-binding molecule in blood of poison frogs. Proteomic and biochemical studies establish this plasma protein to be a liver-derived alkaloid-binding globulin (ABG) that is a member of the serine-protease inhibitor (serpin) family. In addition to alkaloid-binding activity, ABG sequesters and regulates the bioavailability of 'free' plasma alkaloids in vitro. Unexpectedly, ABG is not related to saxiphilin, albumin, or other known vitamin carriers, but instead exhibits sequence and structural homology to mammalian hormone carriers and amphibian biliverdin-binding proteins. ABG represents a new small molecule binding functionality in serpin proteins, a novel mechanism of plasma alkaloid transport in poison frogs, and more broadly points toward serpins acting as tunable scaffolds for small molecule binding and transport across different organisms.
Collapse
Affiliation(s)
| | | | - Maria Dolores Moya Garzon
- Sarafan ChEM-H, Stanford UniversityStanfordUnited States
- Wu Tsai Institute for Neuroscience, Stanford UniversityStanfordUnited States
- Department of Pathology, Stanford UniversityStanfordUnited States
| | - Alexandra E Rangel
- Wu Tsai Human Performance Alliance, Stanford UniversityStanfordUnited States
| | - Elicio E Tapia
- Department of Radiology, Stanford UniversityStanfordUnited States
| | - Julia T Tanzo
- Sarafan ChEM-H, Stanford UniversityStanfordUnited States
- Wu Tsai Institute for Neuroscience, Stanford UniversityStanfordUnited States
| | - H Tom Soh
- Wu Tsai Human Performance Alliance, Stanford UniversityStanfordUnited States
- Center for Taxonomy and Morphology, Leibniz Institute for the Analysis of Biodiversity ChangeHamburgGermany
- Department of Electrical Engineering, Stanford UniversityStanfordUnited States
| | | | - Jonathan Z Long
- Sarafan ChEM-H, Stanford UniversityStanfordUnited States
- Wu Tsai Institute for Neuroscience, Stanford UniversityStanfordUnited States
- Department of Pathology, Stanford UniversityStanfordUnited States
- Centro Jambatu de Investigación y Conservación de Anfibios, Fundación JambatuSan RafaelEcuador
| | - Lauren A O'Connell
- Department of Biology, Stanford UniversityStanfordUnited States
- Wu Tsai Institute for Neuroscience, Stanford UniversityStanfordUnited States
- Stanford Diabetes Research Center, Stanford UniversityStanfordUnited States
| |
Collapse
|
3
|
Gonzalez M, Carazzone C. Eco-Metabolomics Applied to the Chemical Ecology of Poison Frogs (Dendrobatoidea). J Chem Ecol 2023; 49:570-598. [PMID: 37594619 PMCID: PMC10725362 DOI: 10.1007/s10886-023-01443-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/03/2023] [Accepted: 07/05/2023] [Indexed: 08/19/2023]
Abstract
Amphibians are one of the most remarkable sources of unique natural products. Biogenic amines, peptides, bufodienolides, alkaloids, and volatile organic compounds have been characterized in different species. The superfamily Dendrobatoidea represents one of the most enigmatic cases of study in chemical ecology because their skin secretome is composed by a complex mixture (i.e. cocktail) of highly lethal and noxious unique alkaloid structures. While chemical defences from dendrobatoids (families Dendrobatidae and Aromobatidae) have been investigated employing ecological, behavioral, phylogenetic and evolutionary perspectives, studies about the analytical techniques needed to perform the chemical characterization have been neglected for many years. Therefore, our aim is to summarize the current methods applied for the characterization of chemical profiles in dendrobatoids and to illustrate innovative Eco-metabolomics strategies that could be translated to this study model. This approach could be extended to natural products other than alkaloids and implemented for the chemical analysis of different species of dendrobatoids employing both low- and high-resolution mass spectrometers. Here, we overview important biological features to be considered, procedures that could be applied to perform the chemical characterization, steps and tools to perform an Eco-metabolomic analysis, and a final discussion about future perspectives.
Collapse
Affiliation(s)
- Mabel Gonzalez
- Department of Chemistry, Universidad de los Andes, 4976, Bogotá, AA, Colombia.
- Department of Biology, Stanford University, Palo Alto, CA, 94305, USA.
| | - Chiara Carazzone
- Department of Chemistry, Universidad de los Andes, 4976, Bogotá, AA, Colombia.
| |
Collapse
|
4
|
Fitzpatrick LLJ, Ligabue-Braun R, Nekaris KAI. Slowly Making Sense: A Review of the Two-Step Venom System within Slow ( Nycticebus spp.) and Pygmy Lorises ( Xanthonycticebus spp.). Toxins (Basel) 2023; 15:514. [PMID: 37755940 PMCID: PMC10536643 DOI: 10.3390/toxins15090514] [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: 07/07/2023] [Revised: 08/16/2023] [Accepted: 08/18/2023] [Indexed: 09/28/2023] Open
Abstract
Since the early 2000s, studies of the evolution of venom within animals have rapidly expanded, offering new revelations on the origins and development of venom within various species. The venomous mammals represent excellent opportunities to study venom evolution due to the varying functional usages, the unusual distribution of venom across unrelated mammals and the diverse variety of delivery systems. A group of mammals that excellently represents a combination of these traits are the slow (Nycticebus spp.) and pygmy lorises (Xanthonycticebus spp.) of south-east Asia, which possess the only confirmed two-step venom system. These taxa also present one of the most intriguing mixes of toxic symptoms (cytotoxicity and immunotoxicity) and functional usages (intraspecific competition and ectoparasitic defence) seen in extant animals. We still lack many pieces of the puzzle in understanding how this venom system works, why it evolved what is involved in the venom system and what triggers the toxic components to work. Here, we review available data building upon a decade of research on this topic, focusing especially on why and how this venom system may have evolved. We discuss that research now suggests that venom in slow lorises has a sophisticated set of multiple uses in both intraspecific competition and the potential to disrupt the immune system of targets; we suggest that an exudate diet reveals several toxic plants consumed by slow and pygmy lorises that could be sequestered into their venom and which may help heal venomous bite wounds; we provide the most up-to-date visual model of the brachial gland exudate secretion protein (BGEsp); and we discuss research on a complement component 1r (C1R) protein in saliva that may solve the mystery of what activates the toxicity of slow and pygmy loris venom. We conclude that the slow and pygmy lorises possess amongst the most complex venom system in extant animals, and while we have still a lot more to understand about their venom system, we are close to a breakthrough, particularly with current technological advances.
Collapse
Affiliation(s)
- Leah Lucy Joscelyne Fitzpatrick
- Nocturnal Primate Research Group, Department of Social Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
- Centre for Functional Genomics, Department of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Rodrigo Ligabue-Braun
- Department of Pharmacosciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Avenida Sarmento Leite 245, Porto Alegre 90050-170, Brazil;
| | - K. Anne-Isola Nekaris
- Nocturnal Primate Research Group, Department of Social Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
- Centre for Functional Genomics, Department of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| |
Collapse
|
5
|
Mancuso M, Zaman S, Maddock ST, Kamei RG, Salazar-Valenzuela D, Wilkinson M, Roelants K, Fry BG. Resistance Is Not Futile: Widespread Convergent Evolution of Resistance to Alpha-Neurotoxic Snake Venoms in Caecilians (Amphibia: Gymnophiona). Int J Mol Sci 2023; 24:11353. [PMID: 37511112 PMCID: PMC10379402 DOI: 10.3390/ijms241411353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/30/2023] Open
Abstract
Predatory innovations impose reciprocal selection pressures upon prey. The evolution of snake venom alpha-neurotoxins has triggered the corresponding evolution of resistance in the post-synaptic nicotinic acetylcholine receptors of prey in a complex chemical arms race. All other things being equal, animals like caecilians (an Order of legless amphibians) are quite vulnerable to predation by fossorial elapid snakes and their powerful alpha-neurotoxic venoms; thus, they are under strong selective pressure. Here, we sequenced the nicotinic acetylcholine receptor alpha-1 subunit of 37 caecilian species, representing all currently known families of caecilians from across the Americas, Africa, and Asia, including species endemic to the Seychelles. Three types of resistance were identified: (1) steric hindrance from N-glycosylated asparagines; (2) secondary structural changes due to the replacement of proline by another amino acid; and (3) electrostatic charge repulsion of the positively charged neurotoxins, through the introduction of a positively charged amino acid into the toxin-binding site. We demonstrated that resistance to alpha-neurotoxins convergently evolved at least fifteen times across the caecilian tree (three times in Africa, seven times in the Americas, and five times in Asia). Additionally, as several species were shown to possess multiple resistance modifications acting synergistically, caecilians must have undergone at least 20 separate events involving the origin of toxin resistance. On the other hand, resistance in non-caecilian amphibians was found to be limited to five origins. Together, the mutations underlying resistance in caecilians constitute a robust signature of positive selection which strongly correlates with elapid presence through both space (sympatry with caecilian-eating elapids) and time (Cenozoic radiation of elapids). Our study demonstrates the extent of convergent evolution that can be expected when a single widespread predatory adaptation triggers parallel evolutionary arms races at a global scale.
Collapse
Affiliation(s)
- Marco Mancuso
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Shabnam Zaman
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Simon T Maddock
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
- School of Life Sciences, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
- Island Biodiversity and Conservation Centre, University of Seychelles, Mahé P.O. Box 1348, Seychelles
| | - Rachunliu G Kamei
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
- Amphibians and Reptiles Division, The Field Museum of Natural History, 1400 S Lake Shore Dr., Chicago, IL 60605, USA
| | - David Salazar-Valenzuela
- Centro de Investigación de la Biodiversidad y Cambio Climático (BioCamb) e Ingeniería en Biodiversidad y Recursos Genéticos, Facultad de Ciencias de Medio Ambiente, Universidad Indoamérica, Machala y Sabanilla, Quito EC170301, Ecuador
| | - Mark Wilkinson
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
| | - Kim Roelants
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Bryan G Fry
- Venom Evolutionary Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia
| |
Collapse
|
6
|
A Pore Forming Toxin-like Protein Derived from Chinese Red Belly Toad Bombina maxima Triggers the Pyroptosis of Hippomal Neural Cells and Impairs the Cognitive Ability of Mice. Toxins (Basel) 2023; 15:toxins15030191. [PMID: 36977082 PMCID: PMC10054870 DOI: 10.3390/toxins15030191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/22/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
Toxin-like proteins and peptides of skin secretions from amphibians play important physiological and pathological roles in amphibians. βγ-CAT is a Chinese red-belly toad-derived pore-forming toxin-like protein complex that consists of aerolysin domain, crystalline domain, and trefoil factor domain and induces various toxic effects via its membrane perforation process, including membrane binding, oligomerization, and endocytosis. Here, we observed the death of mouse hippocampal neuronal cells induced by βγ-CAT at a concentration of 5 nM. Subsequent studies showed that the death of hippocampal neuronal cells was accompanied by the activation of Gasdermin E and caspase-1, suggesting that βγ-CAT induces the pyroptosis of hippocampal neuronal cells. Further molecular mechanism studies revealed that the pyroptosis induced by βγ-CAT is dependent on the oligomerization and endocytosis of βγ-CAT. It is well known that the damage of hippocampal neuronal cells leads to the cognitive attenuation of animals. The impaired cognitive ability of mice was observed after intraperitoneal injection with 10 μg/kg βγ-CAT in a water maze assay. Taken together, these findings reveal a previously unknown toxicological function of a vertebrate-derived pore-forming toxin-like protein in the nerve system, which triggers the pyroptosis of hippocampal neuronal cells, ultimately leading to hippocampal cognitive attenuation.
Collapse
|
7
|
Moskowitz NA, D’Agui R, Alvarez-Buylla A, Fiocca K, O’Connell LA. Poison frog dietary preference depends on prey type and alkaloid load. PLoS One 2022; 17:e0276331. [PMID: 36454945 PMCID: PMC9714857 DOI: 10.1371/journal.pone.0276331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 10/04/2022] [Indexed: 12/05/2022] Open
Abstract
The ability to acquire chemical defenses through the diet has evolved across several major taxa. Chemically defended organisms may need to balance chemical defense acquisition and nutritional quality of prey items. However, these dietary preferences and potential trade-offs are rarely considered in the framework of diet-derived defenses. Poison frogs (Family Dendrobatidae) acquire defensive alkaloids from their arthropod diet of ants and mites, although their dietary preferences have never been investigated. We conducted prey preference assays with the Dyeing Poison frog (Dendrobates tinctorius) to test the hypothesis that alkaloid load and prey traits influence frog dietary preferences. We tested size preferences (big versus small) within each of four prey groups (ants, beetles, flies, and fly larvae) and found that frogs preferred interacting with smaller prey items of the fly and beetle groups. Frog taxonomic prey preferences were also tested as we experimentally increased their chemical defense load by feeding frogs decahydroquinoline, an alkaloid compound similar to those naturally found in their diet. Contrary to our expectations, overall preferences did not change during alkaloid consumption, as frogs across groups preferred fly larvae over other prey. Finally, we assessed the protein and lipid content of prey items and found that small ants have the highest lipid content while large fly larvae have the highest protein content. Our results suggest that consideration of toxicity and prey nutritional value are important factors in understanding the evolution of acquired chemical defenses and niche partitioning.
Collapse
Affiliation(s)
- Nora A. Moskowitz
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | - Rachel D’Agui
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | | | - Katherine Fiocca
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | - Lauren A. O’Connell
- Department of Biology, Stanford University, Stanford, CA, United States of America
- * E-mail:
| |
Collapse
|
8
|
Definition of a saxitoxin (STX) binding code enables discovery and characterization of the anuran saxiphilin family. Proc Natl Acad Sci U S A 2022; 119:e2210114119. [PMID: 36279441 PMCID: PMC9636910 DOI: 10.1073/pnas.2210114119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
American bullfrog (Rana castesbeiana) saxiphilin (RcSxph) is a high-affinity "toxin sponge" protein thought to prevent intoxication by saxitoxin (STX), a lethal bis-guanidinium neurotoxin that causes paralytic shellfish poisoning (PSP) by blocking voltage-gated sodium channels (NaVs). How specific RcSxph interactions contribute to STX binding has not been defined and whether other organisms have similar proteins is unclear. Here, we use mutagenesis, ligand binding, and structural studies to define the energetic basis of Sxph:STX recognition. The resultant STX "recognition code" enabled engineering of RcSxph to improve its ability to rescue NaVs from STX and facilitated discovery of 10 new frog and toad Sxphs. Definition of the STX binding code and Sxph family expansion among diverse anurans separated by ∼140 My of evolution provides a molecular basis for understanding the roles of toxin sponge proteins in toxin resistance and for developing novel proteins to sense or neutralize STX and related PSP toxins.
Collapse
|
9
|
Krieger AC, Povilaitis SC, Gowda P, O’Connell LA, Eberlin LS. Noninvasive Detection of Chemical Defenses in Poison Frogs Using the MasSpec Pen. ACS MEASUREMENT SCIENCE AU 2022; 2:475-484. [PMID: 36281295 PMCID: PMC9585640 DOI: 10.1021/acsmeasuresciau.2c00035] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/25/2022] [Accepted: 07/27/2022] [Indexed: 06/16/2023]
Abstract
Poison frogs are well-known for their fascinating ability to store alkaloids in their skin as chemical defense against predators. Chemical methods used to study these alkaloids are limited by requirements for euthanasia or stress during sampling. Here, we demonstrate sensitive and biocompatible alkaloid detection and monitoring in vivo using the MasSpec Pen, a handheld, noninvasive chemical detection device coupled to a mass spectrometer. The MasSpec Pen allowed rapid (<15 s), gentle, and consecutive molecular analysis without harm or undue stress to the animals. Through a month-long alkaloid-feeding study with the dyeing poison frog, we observed temporal dynamics of chemical sequestration in vivo by comparing frogs fed the alkaloid decahydroquinoline (DHQ) to vehicle-fed frogs. We also demonstrate the feasibility of the MasSpec Pen for the untargeted detection of rich alkaloid profiles from skin extracts of the Diablito poison frog, collected from two distinct geographical populations in Ecuador. The results obtained in this study demonstrate the utility of the MasSpec Pen for direct, rapid, and biocompatible analysis of poison frog alkaloids.
Collapse
Affiliation(s)
- Anna C. Krieger
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Sydney C. Povilaitis
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Prajwal Gowda
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Lauren A. O’Connell
- Department
of Biology, Stanford University, Stanford, California 94305, United States
| | - Livia S. Eberlin
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
- Department
of Surgery, Baylor College of Medicine, Houston, Texas 77030, United States
| |
Collapse
|
10
|
Jeckel AM, Bolton SK, Waters KR, Antoniazzi MM, Jared C, Matsumura K, Nishikawa K, Morimoto Y, Grant T, Saporito RA. Dose-dependent alkaloid sequestration and N-methylation of decahydroquinoline in poison frogs. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2022; 337:537-546. [PMID: 35201668 DOI: 10.1002/jez.2587] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 12/22/2021] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Sequestration of chemical defenses from dietary sources is dependent on the availability of compounds in the environment and the mechanism of sequestration. Previous experiments have shown that sequestration efficiency varies among alkaloids in poison frogs, but little is known about the underlying mechanism. The aim of this study was to quantify the extent to which alkaloid sequestration and modification are dependent on alkaloid availability and/or sequestration mechanism. To do this, we administered different doses of histrionicotoxin (HTX) 235A and decahydroquinoline (DHQ) to captive-bred Adelphobates galactonotus and measured alkaloid quantity in muscle, kidney, liver, and feces. HTX 235A and DHQ were detected in all organs, whereas only DHQ was present in trace amounts in feces. For both liver and skin, the quantity of alkaloid accumulated increased at higher doses for both alkaloids. Accumulation efficiency in the skin increased at higher doses for HTX 235A but remained constant for DHQ. In contrast, the efficiency of HTX 235A accumulation in the liver was inversely related to dose and a similar, albeit statistically nonsignificant, pattern was observed for DHQ. We identified and quantified the N-methylation of DHQ in A. galactonotus, which represents a previously unknown example of alkaloid modification in poison frogs. Our study suggests that variation in alkaloid composition among individuals and species can result from differences in sequestration efficiency related to the type and amount of alkaloids available in the environment.
Collapse
Affiliation(s)
- Adriana M Jeckel
- Department of Zoology, Institute of Biosciences, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Sarah K Bolton
- Department of Biology, Notre Dame College, South Euclid, Ohio, USA
| | - Katherine R Waters
- Department of Biology, John Carroll University, University Heights, Ohio, USA
| | - Marta M Antoniazzi
- Structural Biology Lab, Butantan Institute, São Paulo, São Paulo, Brazil
| | - Carlos Jared
- Structural Biology Lab, Butantan Institute, São Paulo, São Paulo, Brazil
| | - Kunihiro Matsumura
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Keisuke Nishikawa
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Yoshiki Morimoto
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Taran Grant
- Department of Zoology, Institute of Biosciences, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Ralph A Saporito
- Department of Biology, John Carroll University, University Heights, Ohio, USA
| |
Collapse
|
11
|
van Thiel J, Khan MA, Wouters RM, Harris RJ, Casewell NR, Fry BG, Kini RM, Mackessy SP, Vonk FJ, Wüster W, Richardson MK. Convergent evolution of toxin resistance in animals. Biol Rev Camb Philos Soc 2022; 97:1823-1843. [PMID: 35580905 PMCID: PMC9543476 DOI: 10.1111/brv.12865] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 04/22/2022] [Accepted: 04/26/2022] [Indexed: 12/17/2022]
Abstract
Convergence is the phenomenon whereby similar phenotypes evolve independently in different lineages. One example is resistance to toxins in animals. Toxins have evolved many times throughout the tree of life. They disrupt molecular and physiological pathways in target species, thereby incapacitating prey or deterring a predator. In response, molecular resistance has evolved in many species exposed to toxins to counteract their harmful effects. Here, we review current knowledge on the convergence of toxin resistance using examples from a wide range of toxin families. We explore the evolutionary processes and molecular adaptations driving toxin resistance. However, resistance adaptations may carry a fitness cost if they disrupt the normal physiology of the resistant animal. Therefore, there is a trade‐off between maintaining a functional molecular target and reducing toxin susceptibility. There are relatively few solutions that satisfy this trade‐off. As a result, we see a small set of molecular adaptations appearing repeatedly in diverse animal lineages, a phenomenon that is consistent with models of deterministic evolution. Convergence may also explain what has been called ‘autoresistance’. This is often thought to have evolved for self‐protection, but we argue instead that it may be a consequence of poisonous animals feeding on toxic prey. Toxin resistance provides a unique and compelling model system for studying the interplay between trophic interactions, selection pressures and the molecular mechanisms underlying evolutionary novelties.
Collapse
Affiliation(s)
- Jory van Thiel
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Muzaffar A Khan
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Roel M Wouters
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Richard J Harris
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, 4072, Australia
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, U.K
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, 4072, Australia
| | - R Manjunatha Kini
- Department of Biological Sciences, National University of Singapore, Singapore, 117558, Singapore.,Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117600, Singapore.,Department of Biochemistry, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, 23298, U.S.A
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, CO, 80639-0017, U.S.A
| | - Freek J Vonk
- Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands.,Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, The Netherlands
| | - Wolfgang Wüster
- Molecular Ecology and Fisheries Genetics Laboratory, School of Natural Sciences, Bangor University, Bangor, LL57 2UW, U.K
| | - Michael K Richardson
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| |
Collapse
|
12
|
Firneno TJ, Ramesh B, Maldonado JA, Hernandez-Briones AI, Emery AH, Roelke CE, Fujita MK. Transcriptomic analysis reveals potential candidate pathways and genes involved in toxin biosynthesis in true toads. J Hered 2022; 113:311-324. [PMID: 35325156 DOI: 10.1093/jhered/esac015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/21/2022] [Indexed: 11/13/2022] Open
Abstract
Synthesized chemical defenses have broadly evolved across countless taxa and are important in shaping evolutionary and ecological interactions within ecosystems. However, the underlying genomic mechanisms by which these organisms synthesize and utilize their toxins are relatively unknown. Herein, we use comparative transcriptomics to uncover potential toxin synthesizing genes and pathways, as well as interspecific patterns of toxin synthesizing genes across ten species of North American true toads (Bufonidae). Upon assembly and annotation of the ten transcriptomes, we explored patterns of relative gene expression and possible protein-protein interactions across the species to determine what genes and/or pathways may be responsible for toxin synthesis. We also tested our transcriptome dataset for signatures of positive selection to reveal how selection may be acting upon potential toxin producing genes. We assembled high quality transcriptomes of the bufonid parotoid gland, a tissue not often investigated in other bufonid related RNAseq studies. We found several genes involved in metabolic and biosynthetic pathways (e.g. steroid biosynthesis, terpenoid backbone biosynthesis, isoquinoline biosynthesis, glucosinolate biosynthesis) that were functionally enriched and/or relatively expressed across the ten focal species that may be involved in the synthesis of alkaloid and steroid toxins, as well as other small metabolic compounds that cause distastefulness in bufonids. We hope that our study lays a foundation for future studies to explore the genomic underpinnings and specific pathways of toxin synthesis in toads, as well as at the macroevolutionary scale across numerous taxa that produce their own defensive toxins.
Collapse
Affiliation(s)
- Thomas J Firneno
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA.,Amphibian and Reptile Diversity Research Center, Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
| | - Balan Ramesh
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
| | - Jose A Maldonado
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA.,Amphibian and Reptile Diversity Research Center, Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
| | | | - Alyson H Emery
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
| | - Corey E Roelke
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA.,Amphibian and Reptile Diversity Research Center, Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
| | - Matthew K Fujita
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA.,Amphibian and Reptile Diversity Research Center, Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
| |
Collapse
|
13
|
Affiliation(s)
- Roberto Márquez
- Department of Ecology and Evolution, University of Chicago, Chicago, IL.,Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI
| |
Collapse
|
14
|
Abderemane-Ali F, Rossen ND, Kobiela ME, Craig RA, Garrison CE, Chen Z, Colleran CM, O’Connell LA, Du Bois J, Dumbacher JP, Minor DL. Evidence that toxin resistance in poison birds and frogs is not rooted in sodium channel mutations and may rely on "toxin sponge" proteins. J Gen Physiol 2021; 153:e202112872. [PMID: 34351379 PMCID: PMC8348241 DOI: 10.1085/jgp.202112872] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 05/30/2021] [Accepted: 07/01/2021] [Indexed: 12/18/2022] Open
Abstract
Many poisonous organisms carry small-molecule toxins that alter voltage-gated sodium channel (NaV) function. Among these, batrachotoxin (BTX) from Pitohui poison birds and Phyllobates poison frogs stands out because of its lethality and unusual effects on NaV function. How these toxin-bearing organisms avoid autointoxication remains poorly understood. In poison frogs, a NaV DIVS6 pore-forming helix N-to-T mutation has been proposed as the BTX resistance mechanism. Here, we show that this variant is absent from Pitohui and poison frog NaVs, incurs a strong cost compromising channel function, and fails to produce BTX-resistant channels in poison frog NaVs. We also show that captivity-raised poison frogs are resistant to two NaV-directed toxins, BTX and saxitoxin (STX), even though they bear NaVs sensitive to both. Moreover, we demonstrate that the amphibian STX "toxin sponge" protein saxiphilin is able to protect and rescue NaVs from block by STX. Taken together, our data contradict the hypothesis that BTX autoresistance is rooted in the DIVS6 N→T mutation, challenge the idea that ion channel mutations are a primary driver of toxin resistance, and suggest the possibility that toxin sequestration mechanisms may be key for protecting poisonous species from the action of small-molecule toxins.
Collapse
Affiliation(s)
- Fayal Abderemane-Ali
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
| | - Nathan D. Rossen
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
| | - Megan E. Kobiela
- School of Biological Sciences, University of Nebraska–Lincoln, Lincoln, NE
| | | | | | - Zhou Chen
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
| | - Claire M. Colleran
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
| | | | - J. Du Bois
- Department of Chemistry, Stanford University, Stanford, CA
| | - John P. Dumbacher
- Institute for Biodiversity Science and Sustainability, California Academy of Sciences, San Francisco, CA
- Department of Biology, San Francisco State University, San Francisco, CA
| | - Daniel L. Minor
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA
- California Institute for Quantitative Biomedical Research, University of California, San Francisco, San Francisco, CA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA
- Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA
| |
Collapse
|