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Jensen GW, van der Smagt P, Luksch H, Straka H, Kohl T. Chronic Multi-Electrode Electromyography in Snakes. Front Behav Neurosci 2022; 15:761891. [PMID: 35069138 PMCID: PMC8777293 DOI: 10.3389/fnbeh.2021.761891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 12/06/2021] [Indexed: 11/25/2022] Open
Abstract
Knowledge about body motion kinematics and underlying muscle contraction dynamics usually derives from electromyographic (EMG) recordings. However, acquisition of such signals in snakes is challenging because electrodes either attached to or implanted beneath the skin may unintentionally be removed by force or friction caused from undulatory motion, thus severely impeding chronic EMG recordings. Here, we present a reliable method for stable subdermal implantation of up to eight bipolar electrodes above the target muscles. The mechanical stability of the inserted electrodes and the overnight coverage of the snake body with a “sleeping bag” ensured the recording of reliable and robust chronic EMG activity. The utility of the technique was verified by daily acquisition of high signal-to-noise activity from all target sites over four consecutive days during stimulus-evoked postural reactions in Amazon tree boas and Western diamondback rattlesnakes. The successful demonstration of the chronic recording suggests that this technique can improve acute experiments by enabling the collection of larger data sets from single individuals.
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Affiliation(s)
- Grady W. Jensen
- Graduate School of Systemic Neurosciences (GSN-LMU), Ludwig-Maximilians-University, Munich, Germany
- ARGMAX.AI Volkswagen Group Machine Learning Research Lab, Munich, Germany
| | - Patrick van der Smagt
- Graduate School of Systemic Neurosciences (GSN-LMU), Ludwig-Maximilians-University, Munich, Germany
- ARGMAX.AI Volkswagen Group Machine Learning Research Lab, Munich, Germany
- Department of Artificial Intelligence, Faculty of Informatics, Eötvös Lórand University, Budapest, Germany
| | - Harald Luksch
- Chair of Zoology, Technical University of Munich, Freising, Germany
| | - Hans Straka
- Department Biology II, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Tobias Kohl
- Chair of Zoology, Technical University of Munich, Freising, Germany
- *Correspondence: Tobias Kohl
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2
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Avella I, Barajas-Ledesma E, Casewell NR, Harrison RA, Rowley PD, Crittenden E, Wüster W, Castiglia R, Holland C, van der Meijden A. Unexpected lack of specialisation in the flow properties of spitting cobra venom. J Exp Biol 2021; 224:238100. [PMID: 33827968 DOI: 10.1242/jeb.229229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 02/16/2021] [Indexed: 12/14/2022]
Abstract
Venom spitting is a defence mechanism based on airborne venom delivery used by a number of different African and Asian elapid snake species ('spitting cobras'; Naja spp. and Hemachatus spp.). Adaptations underpinning venom spitting have been studied extensively at both behavioural and morphological level in cobras, but the role of the physical properties of venom itself in its effective projection remains largely unstudied. We hereby provide the first comparative study of the physical properties of venom in spitting and non-spitting cobras. We measured the viscosity, protein concentration and pH of the venom of 13 cobra species of the genus Naja from Africa and Asia, alongside the spitting elapid Hemachatus haemachatus and the non-spitting viper Bitis arietans By using published microCT scans, we calculated the pressure required to eject venom through the fangs of a spitting and a non-spitting cobra. Despite the differences in the modes of venom delivery, we found no significant differences between spitters and non-spitters in the rheological and physical properties of the studied venoms. Furthermore, all analysed venoms showed a Newtonian flow behaviour, in contrast to previous reports. Although our results imply that the evolution of venom spitting did not significantly affect venom viscosity, our models of fang pressure suggests that the pressure requirements to eject venom are lower in spitting cobras than in non-spitting cobras.
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Affiliation(s)
- Ignazio Avella
- CIBIO/InBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, 4485-661 Vairão, Portugal
| | - Edgar Barajas-Ledesma
- Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, UK
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Robert A Harrison
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Paul D Rowley
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Edouard Crittenden
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Wolfgang Wüster
- Molecular Ecology and Fisheries Genetics Laboratory, School of Natural Sciences, Bangor University, Bangor LL57 2UW, UK
| | - Riccardo Castiglia
- Dipartimento di Biologia e Biotecnologie 'Charles Darwin', Università di Roma 'La Sapienza', 00185 Rome, Italy
| | - Chris Holland
- Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, UK
| | - Arie van der Meijden
- CIBIO/InBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, 4485-661 Vairão, Portugal
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3
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Panagides N, Jackson TNW, Ikonomopoulou MP, Arbuckle K, Pretzler R, Yang DC, Ali SA, Koludarov I, Dobson J, Sanker B, Asselin A, Santana RC, Hendrikx I, van der Ploeg H, Tai-A-Pin J, van den Bergh R, Kerkkamp HMI, Vonk FJ, Naude A, Strydom MA, Jacobsz L, Dunstan N, Jaeger M, Hodgson WC, Miles J, Fry BG. How the Cobra Got Its Flesh-Eating Venom: Cytotoxicity as a Defensive Innovation and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting. Toxins (Basel) 2017; 9:E103. [PMID: 28335411 PMCID: PMC5371858 DOI: 10.3390/toxins9030103] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/19/2017] [Accepted: 03/05/2017] [Indexed: 11/30/2022] Open
Abstract
The cytotoxicity of the venom of 25 species of Old World elapid snake was tested and compared with the morphological and behavioural adaptations of hooding and spitting. We determined that, contrary to previous assumptions, the venoms of spitting species are not consistently more cytotoxic than those of closely related non-spitting species. While this correlation between spitting and non-spitting was found among African cobras, it was not present among Asian cobras. On the other hand, a consistent positive correlation was observed between cytotoxicity and utilisation of the defensive hooding display that cobras are famous for. Hooding and spitting are widely regarded as defensive adaptations, but it has hitherto been uncertain whether cytotoxicity serves a defensive purpose or is somehow useful in prey subjugation. The results of this study suggest that cytotoxicity evolved primarily as a defensive innovation and that it has co-evolved twice alongside hooding behavior: once in the Hemachatus + Naja and again independently in the king cobras (Ophiophagus). There was a significant increase of cytotoxicity in the Asian Naja linked to the evolution of bold aposematic hood markings, reinforcing the link between hooding and the evolution of defensive cytotoxic venoms. In parallel, lineages with increased cytotoxicity but lacking bold hood patterns evolved aposematic markers in the form of high contrast body banding. The results also indicate that, secondary to the evolution of venom rich in cytotoxins, spitting has evolved three times independently: once within the African Naja, once within the Asian Naja, and once in the Hemachatus genus. The evolution of cytotoxic venom thus appears to facilitate the evolution of defensive spitting behaviour. In contrast, a secondary loss of cytotoxicity and reduction of the hood occurred in the water cobra Naja annulata, which possesses streamlined neurotoxic venom similar to that of other aquatic elapid snakes (e.g., hydrophiine sea snakes). The results of this study make an important contribution to our growing understanding of the selection pressures shaping the evolution of snake venom and its constituent toxins. The data also aid in elucidating the relationship between these selection pressures and the medical impact of human snakebite in the developing world, as cytotoxic cobras cause considerable morbidity including loss-of-function injuries that result in economic and social burdens in the tropics of Asia and sub-Saharan Africa.
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Affiliation(s)
- Nadya Panagides
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Timothy N W Jackson
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Maria P Ikonomopoulou
- QIMR Berghofer Institute of Medical Research, Herston, QLD 4049, Australia.
- School of Medicine, The University of Queensland, Herston, QLD 4002, Australia.
| | - Kevin Arbuckle
- Department of Biosciences, College of Science, Swansea University, Swansea SA2 8PP, UK.
| | - Rudolf Pretzler
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Daryl C Yang
- Monash Venom Group, Department of Pharmacology, Monash University, Clayton VIC 3800, Australia.
| | - Syed A Ali
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
- HEJ Research Institute of Chemistry, International Centre for Chemical and Biological Sciences (ICCBS), University of Karachi, Karachi 75270, Pakistan.
| | - Ivan Koludarov
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
| | - James Dobson
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Brittany Sanker
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Angelique Asselin
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Renan C Santana
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Iwan Hendrikx
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Harold van der Ploeg
- Working Group Adder Research Netherlands, RAVON, 6525 ED Nijmegen, The Netherlands.
| | - Jeremie Tai-A-Pin
- Working Group Venomous Bites Netherlands, RAVON, 6525 ED Nijmegen, The Netherlands.
| | | | - Harald M I Kerkkamp
- Institute of Biology Leiden (IBL), Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
| | - Freek J Vonk
- Naturalis Biodiversity Center, 2333 CR Leiden, The Netherlands.
| | - Arno Naude
- Snakebite Assist, Pretoria ZA-0001, South Africa.
| | - Morné A Strydom
- Department Pharmacology, University of Pretoria, Pretoria ZA-0001, South Africa.
- SYNEXUS Clinical Research SA Pty Ltd., Pretoria ZA-0001, South Africa.
| | - Louis Jacobsz
- Zoology Department, University of Pretoria, Pretoria ZA-0001, South Africa.
| | - Nathan Dunstan
- Venom Supplies, Tanunda, South Australia 5352, Australia.
| | - Marc Jaeger
- Planet Exotica, 5 Avenue des Fleurs de la Paix, 17204 Royan, France.
| | - Wayne C Hodgson
- Monash Venom Group, Department of Pharmacology, Monash University, Clayton VIC 3800, Australia.
| | - John Miles
- QIMR Berghofer Institute of Medical Research, Herston, QLD 4049, Australia.
- School of Medicine, The University of Queensland, Herston, QLD 4002, Australia.
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD 4878, Australia.
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
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Westhoff G, Boetig M, Bleckmann H, Young BA. Target tracking during venom 'spitting' by cobras. ACTA ACUST UNITED AC 2010; 213:1797-802. [PMID: 20472765 DOI: 10.1242/jeb.037135] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Spitting cobras, which defend themselves by streaming venom towards the face and/or eyes of a predator, must be highly accurate because the venom they spit is only an effective deterrent if it lands on the predator's cornea. Several factors make this level of accuracy difficult to achieve; the target is moving, is frequently >1 m away from the snake and the venom stream is released in approximately 50 ms. In the present study we show that spitting cobras can accurately track the movements of a potentially threatening vertebrate, and by anticipating its subsequent (short-term) movements direct their venom to maximize the likelihood of striking the target's eye. Unlike other animals that project material, in spitting cobras the discharge orifice (the fang) is relatively fixed so directing the venom stream requires rapid movements of the entire head. The cobra's ability to track and anticipate the target's movement, and to perform rapid cephalic oscillations that coordinate with the target's movements suggest a level of neural processing that has not been attributed to snakes, or other reptiles, previously.
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Affiliation(s)
- Guido Westhoff
- Institute of Zoology, University of Bonn, Bonn 53115, Germany
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