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Mauricio B, Mailho-Fontana PL, Sato LA, Barbosa FF, Astray RM, Kupfer A, Brodie ED, Jared C, Antoniazzi MM. Morphology of the Cutaneous Poison and Mucous Glands in Amphibians with Particular Emphasis on Caecilians ( Siphonops annulatus). Toxins (Basel) 2021; 13:toxins13110779. [PMID: 34822563 PMCID: PMC8617868 DOI: 10.3390/toxins13110779] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/30/2021] [Accepted: 11/02/2021] [Indexed: 01/18/2023] Open
Abstract
Caecilians (order Gymnophiona) are apodan, snake-like amphibians, usually with fossorial habits, constituting one of the most unknown groups of terrestrial vertebrates. As in orders Anura (frogs, tree frogs and toads) and Caudata (salamanders and newts), the caecilian skin is rich in mucous glands, responsible for body lubrication, and poison glands, producing varied toxins used in defence against predators and microorganisms. Whereas in anurans and caudatans skin gland morphology has been well studied, caecilian poison glands remain poorly elucidated. Here we characterised the skin gland morphology of the caecilian Siphonops annulatus, emphasising the poison glands in comparison to those of anurans and salamanders. We showed that S. annulatus glands are similar to those of salamanders, consisting of several syncytial compartments full of granules composed of protein material but showing some differentiated apical compartments containing mucus. An unusual structure resembling a mucous gland is frequently observed in lateral/apical position, apparently connected to the main duct. We conclude that the morphology of skin poison glands in caecilians is more similar to salamander glands when compared to anuran glands that show a much-simplified structure.
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Affiliation(s)
- Beatriz Mauricio
- Laboratory of Structural Biology, Instituto Butantan, São Paulo 05509-000, Brazil; (B.M.); (P.L.M.-F.); (L.A.S.); (M.M.A.)
| | - Pedro Luiz Mailho-Fontana
- Laboratory of Structural Biology, Instituto Butantan, São Paulo 05509-000, Brazil; (B.M.); (P.L.M.-F.); (L.A.S.); (M.M.A.)
| | - Luciana Almeida Sato
- Laboratory of Structural Biology, Instituto Butantan, São Paulo 05509-000, Brazil; (B.M.); (P.L.M.-F.); (L.A.S.); (M.M.A.)
| | - Flavia Ferreira Barbosa
- Multipurpose Laboratory, Instituto Butantan, São Paulo 05503-000, Brazil; (F.F.B.); (R.M.A.)
| | - Renato Mancini Astray
- Multipurpose Laboratory, Instituto Butantan, São Paulo 05503-000, Brazil; (F.F.B.); (R.M.A.)
| | - Alexander Kupfer
- Department of Zoology, State Museum of Natural History, 70191 Stuttgart, Germany;
| | - Edmund D. Brodie
- Department of Biology, Utah State University, Logan, UT 84322, USA;
| | - Carlos Jared
- Laboratory of Structural Biology, Instituto Butantan, São Paulo 05509-000, Brazil; (B.M.); (P.L.M.-F.); (L.A.S.); (M.M.A.)
- Correspondence:
| | - Marta Maria Antoniazzi
- Laboratory of Structural Biology, Instituto Butantan, São Paulo 05509-000, Brazil; (B.M.); (P.L.M.-F.); (L.A.S.); (M.M.A.)
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Li M, Gao Z, Dai T, Chen D, Tong J, Guo L, Wang C. Comparative research on morphology and mechanical property of integument of Rana dybowskii, Xenopus laevis and Ambystoma mexicanum. J Mech Behav Biomed Mater 2021; 117:104382. [PMID: 33607570 DOI: 10.1016/j.jmbbm.2021.104382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 10/22/2022]
Abstract
Amphibians' integument is a multifunctional organ offering protection from the exterior surroundings and facilitating the physiological change of gas, water and salts with the environment, which is a natural biomaterial with multifunctional features. Interspecies comparison of biomechanical characters and microstructure possibly related to them were performed on the integument of three species of amphibians, two anurans(Rana dybowskii and Xenopus laevis) and one urodeles(Ambystoma mexicanum) using tensile testing and morphological characterization. It was found that the integument of Rana dybowskii and Xenopus laevis was covered by polygonal epidermal cells, while the trunk surface of Ambystoma mexicanum presented irregular microstructure with the lack of keratinization. The integument of Rana dybowskii and Xenopus laevis exhibited good performance on stiffness and strength, which showed quite high mean elastic modulus, 931MPa and 1048MPa,respectively.
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Affiliation(s)
- Mo Li
- College of Biological and Agricultural Engineering, Jilin University, Changchun, 130025, China; The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130025, China
| | - Zibo Gao
- College of Biological and Agricultural Engineering, Jilin University, Changchun, 130025, China; The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130025, China
| | - Taidong Dai
- College of Biological and Agricultural Engineering, Jilin University, Changchun, 130025, China; The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130025, China
| | - Donghui Chen
- College of Biological and Agricultural Engineering, Jilin University, Changchun, 130025, China; The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130025, China
| | - Jin Tong
- College of Biological and Agricultural Engineering, Jilin University, Changchun, 130025, China; The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130025, China
| | - Li Guo
- College of Biological and Agricultural Engineering, Jilin University, Changchun, 130025, China; The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130025, China
| | - Chaofei Wang
- College of Biological and Agricultural Engineering, Jilin University, Changchun, 130025, China; The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130025, China.
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Arun D, Sandhya S, Akbarsha MA, Oommen OV, Divya L. An insight into the skin glands, dermal scales and secretions of the caecilian amphibian Ichthyophis beddomei. Saudi J Biol Sci 2020; 27:2683-2690. [PMID: 32994727 PMCID: PMC7499274 DOI: 10.1016/j.sjbs.2020.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 11/17/2022] Open
Abstract
The caecilian amphibians are richly endowed with cutaneous glands, which produce secretory materials that facilitate survival in the hostile subterranean environment. Although India has a fairly abundant distribution of caecilians, there are only very few studies on their skin and secretion. In this background, the skin of Ichthyophis beddomei from the Western Ghats of Kerala, India, was subjected to light and electron microscopic analyses. There are two types of dermal glands, mucous and granular. The mucous gland has a lumen, which is packed with a mucous. The mucous-producing cells are located around the lumen. In the granular gland, a lumen is absent; the bloated secretory cells, filling the gland, are densely packed with granules of different sizes which are elegantly revealed in TEM. There is a lining of myo-epithelial cells in the peripheral regions of the glands. Small flat disk-like dermal scales, dense with squamulae, are embedded in pockets in the dermis, distributed among the cutaneous glands. 1-4 scales of various sizes are present in each scale pocket. Scanning electron microscopic observation of the skin surface revealed numerous glandular openings. The skin gland secretions, exuded through the pores, contain fatty acids, alcohols, steroid, hydrocarbons, terpene, aldehyde and a few unknown compounds.
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Affiliation(s)
- Damodaran Arun
- Department of Zoology, Central University of Kerala, Kasaragod, Kerala, India
| | | | | | - Oommen V. Oommen
- Department of Computational Biology and Bioinformatics, University of Kerala, Thiruvananthapuram, Kerala, India
| | - Lekha Divya
- Department of Zoology, Central University of Kerala, Kasaragod, Kerala, India
- Corresponding author at: Department of Zoology, Central University of Kerala, Kasaragod, Kerala, India.
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Arun D, Akbarsha MA, Oommen OV, Divya L. Light and transmission electron microscopic structure of skin glands and dermal scales of a caecilian amphibian Gegeneophis ramaswamii, with a note on antimicrobial property of skin gland secretion. Microsc Res Tech 2019; 82:1267-1276. [PMID: 31002452 DOI: 10.1002/jemt.23276] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 03/24/2019] [Accepted: 03/29/2019] [Indexed: 11/08/2022]
Abstract
Amphibian skin secretions contain a variety of bioactive compounds that are involved in diverse roles such as communication, homeostasis, defence against predators, pathogens, and so on. Especially, the caecilian amphibians possess numerous cutaneous glands that produce the secretory material, which facilitate survival in their harsh subterranean environment. Inspite of the fact that India has a fairly abundant distribution of caecilian amphibians, there has hardly been any study on their skin and its secretion. Herein, we describe, using light microscopy and electron microscopy, two types of dermal glands, mucous and granular, in Gegeneophis ramaswamii. The mucous glands are filled with mucous materials. The mucous-producing cells are located near the periphery. The granular glands are surrounded by myoepithelial cells. A large number of granules of different sizes are present in the lumen of the granular gland. The granule-producing cells are present near the myoepithelial lining of the gland. There are small flat disk-like dermal scales in pockets in the transverse ridges of the posterior region of the body. Each pocket contains 1-4 scales of various sizes. Scanning electron microscopic (SEM) study of the skin surface showed numerous funnel-shaped glandular openings. The antibacterial activity of the skin secretions was revealed in the test against Escherichia coli, Klebsiella pneumoniae, and Aeromonas hydrophila, all gram-negative bacteria. SEM analyses confirm the membrane damage in bacterial cells on exposure to skin secretions of G. ramaswamii.
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Affiliation(s)
- Damodaran Arun
- Department of Animal Science, Central University of Kerala, Kasaragod, Kerala, India
| | - Mohammad A Akbarsha
- Research coordinator, National College (Autonomous), Tiruchirappalli, Tamil Nadu, India
| | - Oommen V Oommen
- Department of Computational Biology and Bioinformatics, University of Kerala, Thiruvananthapuram, Kerala, India
| | - Lekha Divya
- Department of Animal Science, Central University of Kerala, Kasaragod, Kerala, India
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Wanninger M, Schwaha T, Heiss E. Form and Function of the skin glands in the Himalayan newt Tylototriton verrucosus. ZOOLOGICAL LETTERS 2018; 4:15. [PMID: 29942644 PMCID: PMC5998448 DOI: 10.1186/s40851-018-0095-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 05/11/2018] [Indexed: 05/29/2023]
Abstract
BACKGROUND Amphibians have evolved a remarkable diversity of defensive mechanisms against predators. One of the most conspicuous components in their defense is related to their ability to produce and store a high variety of bioactive (noxious to poisonous) substances in specialized skin glands. Previous studies have shown that T. verrucosus is poisonous with the potential to truly harm or even kill would-be predators by the effect of its toxic skin secretions. However, little is known on form and function of the skin glands responsible for production and release of these secretions. RESULTS By using light- and scanning electron microscopy along with confocal laser scanning microscopy, we show that T. verrucosus exhibits three different multicellular skin glands: one mucous- and two granular glands. While mucous glands are responsible for the production of the slippery mucus, granular glands are considered the production site of toxins. The first type of granular glands (GG1) is found throughout the skin, though its average size can vary between body regions. The second type of granular glands (GG2) can reach larger dimensions compared with the former type and is restricted to the tail region. Despite their different morphology, all three skin gland types are enwrapped by a distinct myoepithelial sheath that is more prominently developed in the granular (i.e. poison-) glands compared to the mucous glands. The myoepithelial sheath consists of one layer of regularly arranged slender myoepithelial cells that run from the gland pore to the basal gland pole. CONCLUSIONS This study shows that the skin in the Himalayan newt T. verrucosus displays one mucus- and two poison gland types enwrapped by a myoepithelial sheath. Contraction of the myoepithelium squeezes the glands and glandular content is released upon the skin surface where the secretion can deploy its defensive potential.
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Affiliation(s)
- Marion Wanninger
- Department of Integrative Zoology, University of Vienna, Althanstr, 14, A-1090 Vienna, Austria
| | - Thomas Schwaha
- Department of Integrative Zoology, University of Vienna, Althanstr, 14, A-1090 Vienna, Austria
| | - Egon Heiss
- Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University of Jena, Erbertstr. 1, 07743 Jena, Germany
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