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Kröner L, Lötters S, Hopp MT. Insights into caudate amphibian skin secretions with a focus on the chemistry and bioactivity of derived peptides. Biol Chem 2024; 0:hsz-2024-0035. [PMID: 38766708 DOI: 10.1515/hsz-2024-0035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 05/06/2024] [Indexed: 05/22/2024]
Abstract
Amphibians are well-known for their ability to produce and secrete a mixture of bioactive substances in specialized skin glands for the purpose of antibiotic self-protection and defense against predators. Some of these secretions contain various small molecules, such as the highly toxic batrachotoxin, tetrodotoxin, and samandarine. For some time, the presence of peptides in amphibian skin secretions has attracted researchers, consisting of a diverse collection of - to the current state of knowledge - three to 104 amino acid long sequences. From these more than 2000 peptides many are known to exert antimicrobial effects. In addition, there are some reports on amphibian skin peptides that can promote wound healing, regulate immunoreactions, and may serve as antiparasitic and antioxidative substances. So far, the focus has mainly been on skin peptides from frogs and toads (Anura), eclipsing the research on skin peptides of the ca. 700 salamanders and newts (Caudata). Just recently, several novel observations dealing with caudate peptides and their structure-function relationships were reported. This review focuses on the chemistry and bioactivity of caudate amphibian skin peptides and their potential as novel agents for clinical applications.
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Affiliation(s)
- Lorena Kröner
- Department of Chemistry, Institute for Integrated Natural Sciences, 38899 University of Koblenz , D-56070 Koblenz, Germany
| | - Stefan Lötters
- Department of Biogeography, University of Trier, D-54286 Trier, Germany
| | - Marie-T Hopp
- Department of Chemistry, Institute for Integrated Natural Sciences, 38899 University of Koblenz , D-56070 Koblenz, Germany
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Herrboldt MA, Steffen MA, McGouran CN, Bonett RM. Pheromone Gene Diversification and the Evolution of Courtship Glands in Plethodontid Salamanders. J Mol Evol 2021; 89:576-587. [PMID: 34392385 DOI: 10.1007/s00239-021-10026-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 07/28/2021] [Indexed: 11/30/2022]
Abstract
Proteinaceous pheromones that diversify through gene duplication can result in shifts in courtship cocktails that may serve as a mechanism for reproductive isolation. The molecular evolution of pheromones has been extensively studied in salamanders, but how these genes and associated novel courtship glands have codiversified has not been evaluated. In this study we used transcriptional analyses to examine the relationship between pheromone diversification and gland type in three divergent lineages of plethodontid salamanders. Our results revealed that plethodontid salamanders express up to eight divergent Sodefrin Precursor-like Factor genes (spf, representing both alpha and beta subfamilies) along with Plethodontid Modulating Factor (pmf) and Plethodontid Receptivity Factor (prf). Expression of pheromone genes is tissue specific with pmf, prf, and some spf genes restricted to the mental gland. In contrast, the caudal gland shows strong expression of the other spf genes. We found evidence for punctuated changes in pheromone cocktail composition related to the loss of metamorphosis, and subsequent extreme reduction of the mental gland, in a paedomorphic lineage. Our study provides insight into how pheromone diversification can be partitioned into unique glands, which may lead to cocktail specificity in behavioral modules during courtship.
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Affiliation(s)
- Madison A Herrboldt
- Department of Biological Science, University of Tulsa, Tulsa, OK, 74104, USA.
| | - Michael A Steffen
- Department of Biological Science, University of Tulsa, Tulsa, OK, 74104, USA
| | - Carissa N McGouran
- Department of Biological Science, University of Tulsa, Tulsa, OK, 74104, USA
| | - Ronald M Bonett
- Department of Biological Science, University of Tulsa, Tulsa, OK, 74104, USA
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Woodley SK, Staub NL. Pheromonal communication in urodelan amphibians. Cell Tissue Res 2021; 383:327-345. [PMID: 33427952 DOI: 10.1007/s00441-020-03408-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/15/2020] [Indexed: 01/24/2023]
Abstract
Pheromonal communication is an ancient and pervasive sensory modality in urodelan amphibians. One family of salamander pheromones (the sodefrin precursor-like factor (SPF) family) originated 300 million years ago, at the origin of amphibians. Although salamanders are often thought of as relatively simple animals especially when compared to mammals, the pheromonal systems are varied and complex with nuanced effects on behavior. Here, we review the function and evolution of pheromonal signals involved in male-female reproductive interactions. After describing common themes of salamander pheromonal communication, we describe what is known about the rich diversity of pheromonal communication in each salamander family. Several pheromones have been described, ranging from simple, invariant molecules to complex, variable blends of pheromones. While some pheromones elicit overt behavioral responses, others have more nuanced effects. Pheromonal signals have diversified within salamander lineages and have experienced rapid evolution. Once receptors have been matched to pheromonal ligands, rapid advance can be made to better understand the olfactory detection and processing of salamander pheromones. In particular, a large number of salamander species deliver pheromones across the skin of females, perhaps reflecting a novel mode of pheromonal communication. At the end of our review, we list some of the many intriguing unanswered questions. We hope that this review will inspire a new generation of scientists to pursue work in this rewarding field.
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Affiliation(s)
- Sarah K Woodley
- Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA.
| | - Nancy L Staub
- Biology Department, Gonzaga University, Spokane, WA, 99203, USA
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Gong Y, Zeng Y, Zheng P, Liao X, Xie F. Structural and bio-functional assessment of the postaxillary gland in Nidirana pleuraden (Amphibia: Anura: Ranidae). ZOOLOGICAL LETTERS 2020; 6:7. [PMID: 32518678 PMCID: PMC7275488 DOI: 10.1186/s40851-020-00160-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Owing to their incomplete adaptation to the terrestrial environment, amphibians possess complex cutaneous glandular systems. The skin glands not only regulate water loss and respiratory gas and salt exchange, but are also involved in defense against predators and microorganisms, social communication, and reproduction. These glands are distributed throughout the integument, but can accumulate in specific regions, forming visible outgrowths known as macroglands. Some macroglands are sexually dimorphic and mediate intersexual communication and reproductive success. The postaxillary gland is a sexually dimorphic macrogland in Nidirana pleuraden. Its biological function and its morphological and histochemical characteristics are unclear. In the present study, we describe the structure and ultrastructure of the postaxillary gland, and explore its main function. RESULTS The postaxillary gland has a thinner epidermis than the dorsal region of N. pleuraden. In addition to ordinary serous glands (OSG), type I and II mucous gland (I MG & II MG), a type of specialized mucous gland (SMG) is also found to constitute the postaxillary gland. The SMG is larger than other gland types, and consists of high columnar mucocytes with basal nuclei arranged radially toward a lumen. SMGs are positive to periodic acid-Schiff stain and stained blue in Masson's trichrome stain. A discontinuous myoepithelial sheath lacking innervation encircles SMG mucocytes, and the outlets of such glands are X- or Y-shaped. Transmission electron microscopy reveals abundant secretory granules in SMG, which are biphasic, composed of an electron-opaque outer ring and a less electron-dense core. Lipid droplets, and organelles, such as rough endoplasmic reticulum and Golgi stacks, are located in the supranuclear cytoplasm of the mucocytes in SMG. Female N. pleuraden exhibits chemotaxis toward homogenate of the postaxillary gland, but male does not. On treatment with trypsin, this sexual attraction disappears. CONCLUSIONS The postaxillary gland of N. pleuraden is a male-specific macrogland that consists primarily of SMGs, together with OSGs, I MGs and II MGs. Other than their extremely large size, SMGs structurally and histochemically resemble many reported specialized gland types in amphibian sexually dimorphic skin glands. Secretions of the postaxillary gland are proteinaceous sexual pheromones, which are believed to attract females at male calling intermissions.
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Affiliation(s)
- Yuzhou Gong
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No. 9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
- Universtiy of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049 People’s Republic of China
| | - Yiwei Zeng
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No. 9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
- Universtiy of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049 People’s Republic of China
| | - Puyang Zheng
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No. 9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
- Universtiy of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049 People’s Republic of China
| | - Xun Liao
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No. 9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
| | - Feng Xie
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No. 9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
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Maex M, Treer D, De Greve H, Proost P, Van Bocxlaer I, Bossuyt F. Exaptation as a Mechanism for Functional Reinforcement of an Animal Pheromone System. Curr Biol 2018; 28:2955-2960.e5. [DOI: 10.1016/j.cub.2018.06.074] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/27/2018] [Accepted: 06/28/2018] [Indexed: 10/28/2022]
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Rollins RE, Staub NL. The Presence of Caudal Courtship-Like Glands in Male and Female Ouachita Dusky Salamanders (Desmognathus brimleyorum). HERPETOLOGICA 2017. [DOI: 10.1655/herpetologica-d-17-00003.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - Nancy L. Staub
- Department of Biology, Gonzaga University, Spokane, WA 99258, USA
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Treer D, Maex M, Van Bocxlaer I, Proost P, Bossuyt F. Divergence of species-specific protein sex pheromone blends in two related, nonhybridizing newts (Salamandridae). Mol Ecol 2017; 27:508-519. [PMID: 29087032 DOI: 10.1111/mec.14398] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 08/17/2017] [Accepted: 08/24/2017] [Indexed: 12/01/2022]
Abstract
In animals that use chemical communication during courtship and reproduction, speciation is often associated with divergence of their sex pheromones. In multicomponent pheromone systems, divergence can be obtained either by adding or deleting components, or by altering the relative contribution of individual components to the mixture. Protein pheromone systems can additionally evolve by amino acid sequence divergence to produce pheromones with a species-specific effect. The sodefrin precursor-like factor (SPF) pheromone system, a blend of proteins that essentially enhances receptivity in salamanders, has had a long and dynamic evolution of gene duplications, but the mechanisms that govern interspecific divergence and the role they play in reproductive isolation remain elusive. Here, we use transcriptomics and proteomics to characterize the SPF protein repertoire of the alpine newt (Ichthyosaura alpestris), and compare it to the previously identified repertoire of SPF proteins of the palmate newt (Lissotriton helveticus), a related but nonhybridizing species. Subsequent phylogenetic analyses indicate that, despite the availability of multiple SPF gene copies, both species predominantly express the same subset of orthologs. Our study demonstrates that species specificity in the SPF protein pheromone system can be established by gradual sequence divergence of the same set of proteins alone.
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Affiliation(s)
- Dag Treer
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Margo Maex
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Ines Van Bocxlaer
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Paul Proost
- Laboratory of Molecular Immunology, Department of Microbiology and Immunology, Rega Institute, Katholieke Universiteit Leuven (K.U. Leuven), Leuven, Belgium
| | - Franky Bossuyt
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
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Silva L, Antunes A. Vomeronasal Receptors in Vertebrates and the Evolution of Pheromone Detection. Annu Rev Anim Biosci 2017; 5:353-370. [DOI: 10.1146/annurev-animal-022516-022801] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Liliana Silva
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, 4050-208 Porto, Portugal
| | - Agostinho Antunes
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, 4050-208 Porto, Portugal
- Department of Biology, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
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Van Bocxlaer I, Maex M, Treer D, Janssenswillen S, Janssens R, Vandebergh W, Proost P, Bossuyt F. Beyond sodefrin: evidence for a multi-component pheromone system in the model newt Cynops pyrrhogaster (Salamandridae). Sci Rep 2016; 6:21880. [PMID: 26935790 PMCID: PMC4776240 DOI: 10.1038/srep21880] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 01/18/2016] [Indexed: 11/09/2022] Open
Abstract
Sodefrin, a decapeptide isolated from the male dorsal gland of the Japanese fire belly newt Cynops pyrrhogaster, was the first peptide pheromone identified from a vertebrate. The fire belly salamander and sodefrin have become a model for sex pheromone investigation in aquatically courting salamanders ever since. Subsequent studies in other salamanders identified SPF protein courtship pheromones of around 20 kDa belonging to the same gene-family. Although transcripts of these proteins could be PCR-amplified in Cynops, it is currently unknown whether they effectively use full-length SPF pheromones next to sodefrin. Here we combined transcriptomics, proteomics and phylogenetics to investigate SPF pheromone use in Cynops pyrrhogaster. Our data show that not sodefrin transcripts, but multiple SPF transcripts make up the majority of the expression profile in the dorsal gland of this newt. Proteome analyses of water in which a male has been courting confirm that this protein blend is effectively secreted and tail-fanned to the female. By combining phylogenetics and expression data, we show that independent evolutionary lineages of these SPF’s were already expressed in ancestral Cynops species before the origin of sodefrin. Extant Cynops species continue to use this multi-component pheromone system, consisting of various proteins in addition to a lineage-specific peptide.
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Affiliation(s)
- Ines Van Bocxlaer
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Margo Maex
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Dag Treer
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Sunita Janssenswillen
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Rik Janssens
- Laboratory of Molecular Immunology, Department of Microbiology and Immunology, KU Leuven - University of Leuven, Minderbroedersstraat 10 - box 1030, B-3000 Leuven, Belgium
| | - Wim Vandebergh
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Paul Proost
- Laboratory of Molecular Immunology, Department of Microbiology and Immunology, KU Leuven - University of Leuven, Minderbroedersstraat 10 - box 1030, B-3000 Leuven, Belgium
| | - Franky Bossuyt
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
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Courtship Pheromone Use in a Model Urodele, the Mexican Axolotl (Ambystoma mexicanum). Sci Rep 2016; 6:20184. [PMID: 26842386 PMCID: PMC4740750 DOI: 10.1038/srep20184] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 12/23/2015] [Indexed: 11/08/2022] Open
Abstract
Sex pheromones have been shown to constitute a crucial aspect of salamander reproduction. Until now, courtship pheromones of Salamandridae and Plethodontidae have been intensively studied, but information on chemical communication in other urodelan families is essentially lacking. The axolotl (Ambystoma mexicanum, Ambystomatidae) has a courtship display that suggests a key role for chemical communication in the orchestration of its sexual behavior, but no sex pheromones have yet been characterized from this species. Here we combined whole transcriptome analyses of the male cloaca with proteomic analyses of water in which axolotls were allowed to court to show that male axolotls secrete multiple ca. 20 kDa glycosylated sodefrin precursor-like factor (SPF) proteins during courtship. In combination with phylogenetic analyses, our data show that the male cloaca essentially secretes a courtship-specific clade of SPF proteins that is orthologous to salamandrid courtship pheromones. In addition, we identified an SPF protein for which no orthologs have been described from other salamanders so far. Overall, our study advocates a central role for SPF proteins during the courtship display of axolotls and adds knowledge on pheromone use in a previously unexplored deep evolutionary branch of salamander evolution.
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