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Gonzalez M, Palacios-Rodriguez P, Hernandez-Restrepo J, González-Santoro M, Amézquita A, Brunetti AE, Carazzone C. First characterization of toxic alkaloids and volatile organic compounds (VOCs) in the cryptic dendrobatid Silverstoneia punctiventris. Front Zool 2021; 18:39. [PMID: 34446035 PMCID: PMC8390233 DOI: 10.1186/s12983-021-00420-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/14/2021] [Indexed: 11/24/2022] Open
Abstract
Background Poison frogs are known for the outstanding diversity of alkaloid-based chemical defences with promising therapeutic applications. However, current knowledge about chemical defences in Dendrobatoidea superfamily has two sources of bias. First, cryptic, brown-colored species have been neglected in comparison to those conspicuously colored, and second, there has been little interest in characterizing metabolites other than alkaloids mediating defensive functions. In an effort to contribute to fill the gap of knowledge about cryptic species and broadening the spectrum of compounds analyzed we have applied head-space solid phase microextraction coupled to gas chromatography and mass spectrometry (HS-SPME/GC-MS) for extracting amphibian alkaloids and volatile organic compounds (VOCs) from Silverstoneia punctiventris. Results Using the skin from 8 specimens in 4 biological replicates we have found 33 different compounds. Twenty of them were classified as VOCs into 15 chemical classes including alkanes, alcohols, carbonyl compounds, methylpyridines, benzothiazoles, N-alkylpyrrolidines, pyrazines, and sesquiterpenoids, some of which were previously reported as repellents, defence compounds or defence pheromones in other organisms, and as sex pheromones in a treefrog. Interestingly, six of the remaining compounds were identified as alkaloids previously reported in other toxic/unpalatable dendrobatid frogs. Conclusions This is the first report of alkaloids and VOCs found in the Silverstoneia genus, which has been assumed for decades as non-chemically defended. This study establishes HS-SPME/GC-MS as a new application for a simultaneous approach to amphibian alkaloids and VOCs in poison frogs while opens up new research questions to assess the co-occurrence of both type of compounds and to investigate the evolutionary significance of a defence gradient that includes olfactory avoidance, unpalatability, and toxicity in dendrobatids. In addition, our results show that amphibian alkaloids could have a dual function (olfactory at distance, taste by contact) never explored before neither in Silverstonaeia nor in any other dendrobatid species. Supplementary Information The online version contains supplementary material available at 10.1186/s12983-021-00420-1.
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Affiliation(s)
- Mabel Gonzalez
- Department of Chemistry, Universidad de los Andes, Bogotá, AA, 4976, Colombia
| | | | | | | | - Adolfo Amézquita
- Department of Biological Sciences, Universidad de los Andes, Bogotá, AA, 4976, Colombia
| | - Andrés E Brunetti
- Laboratorio de Genética Evolutiva, Instituto de Biología Subtropical (CONICET - UNaM), Facultad de Ciencias Exactas, Universidad Nacional de Misiones, N3300, Posadas, Argentina.,Departamento de Ciências Biomoleculares, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903, Ribeirão Preto, SP, Brazil
| | - Chiara Carazzone
- Department of Chemistry, Universidad de los Andes, Bogotá, AA, 4976, Colombia.
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Weeks ENI, Logan JG, Birkett MA, Caulfield JC, Gezan SA, Welham SJ, Brugman VA, Pickett JA, Cameron MM. Electrophysiologically and behaviourally active semiochemicals identified from bed bug refuge substrate. Sci Rep 2020; 10:4590. [PMID: 32165700 PMCID: PMC7067832 DOI: 10.1038/s41598-020-61368-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/21/2020] [Indexed: 11/09/2022] Open
Abstract
Bed bugs are pests of public health importance due to their relentless biting habits that can lead to allergies, secondary infections and mental health issues. When not feeding on human blood bed bugs aggregate in refuges close to human hosts. This aggregation behaviour could be exploited to lure bed bugs into traps for surveillance, treatment efficacy monitoring and mass trapping efforts, if the responsible cues are identified. The aim of this study was to identify and quantify the bed bug aggregation pheromone. Volatile chemicals were collected from bed bug-exposed papers, which are known to induce aggregation behaviour, by air entrainment. This extract was tested for behavioural and electrophysiological activity using a still-air olfactometer and electroantennography, respectively. Coupled gas chromatography-electroantennography (GC-EAG) was used to screen the extract and the GC-EAG-active chemicals, benzaldehyde, hexanal, (E)-2-octenal, octanal, nonanal, decanal, heptanal, (R,S)-1-octen-3-ol, 3-carene, β-phellandrene, (3E,5E)-octadien-2-one, (E)-2-nonenal, 2-decanone, dodecane, nonanoic acid, 2-(2-butoxyethoxy)ethyl acetate, (E)-2-undecanal and (S)-germacrene D, were identified by GC-mass spectrometry and quantified by GC. Synthetic blends, comprising 6, 16, and 18 compounds, at natural ratios, were then tested in the still-air olfactometer to determine behavioural activity. These aggregation chemicals can be manufactured into a lure that could be used to improve bed bug management.
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Affiliation(s)
- E N I Weeks
- Entomology and Nematology Department, University of Florida, 970 Natural Area Drive, Gainesville, Florida, 32611, USA.
| | - J G Logan
- Department of Disease Control, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.,Vecotech Ltd, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - M A Birkett
- Department of Biointeractions and Crop Protection, Rothamsted Research, West Common, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - J C Caulfield
- Department of Biointeractions and Crop Protection, Rothamsted Research, West Common, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - S A Gezan
- VSN International Ltd, 2 Amberside House, Hemel Hempstead, HP2 4TP, UK
| | - S J Welham
- Stats4biol Consultancy, 31 Longcroft Lane, Welwyn Garden City, AL8 6EB, UK
| | - V A Brugman
- Department of Disease Control, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.,Vecotech Ltd, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - J A Pickett
- School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK
| | - M M Cameron
- Department of Disease Control, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.,Vecotech Ltd, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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