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Diagram of the skin of Phyllomedusa bicolor showing the topographic relationships between epidermis, xanthophores, iridophores, melanophores and the mucous, lipid and serous glands. Areas are numbered in correspondence with the following electron micrograph figures (bar: 100 mm).
Source publication
SummaryThe development of the dermal glands of the arboreal frog Phyllomedusa bicolor was investigated by immunocytochemistry and electron microscopy. The 3 types of glands (mucous, lipid and serous) differed in size and secretory activity. The mucous and serous glands were apparent in the tadpole skin, whereas the lipid glands developed later in o...
Contexts in source publication
Context 1
... staining and light microscopy were used to identify three types of acinous glands. The distribution of these glands in the skin of adult frogs is shown in Figure 1. One type has a round single alveolus 150 ± 200 mm in diameter that is connected to the outer layer of the skin epithelium by a short duct. ...
Citations
... Specimens of P. ephippifer in premetamorphosis and most of prometamorphosis exhibit only a stratum corneum and stratum germinativum composing the epidermis, where a stratum compactum forms the dermis. This is different from other specimens of the Hylidae (Lacombe et al. 2000) and Bufonidae (Regueira et al. 2016) which can present thinner and thicker epidermal layers, respectively, during the same developmental phase. The thickness of these layers can also vary according to the body region and between the developmental stages (Fabrezi et al. 2010;Chammas et al. 2015). ...
Throughout metamorphic development until adulthood, amphibians have important integumentary adaptations that maintain their physiological needs and protection against predation. The evolution of these strategies in the subfamily Leiuperinae has been elucidated in recent years. In this sense, the knowledge about Physalaemus ephippifer’s skin features can corroborate the ontogenetic changes of these characteristics in the clade. The aims of this work were to study the ontogeny of the skin of P. ephippifer from tadpole to adult. We collected foam nests in temporary ponds as well as adult individuals in a forest fragment. In the laboratory, the animals were classified by stage development, euthanized, and fixed. Sections of the dorsolateral, lumbar, and femoral portions were dissected from the adult individuals. Samples were submitted to histological processing for light microscopy and scanning electron microscopy. In premetamorphosis phase, granular glands development is absent and secretory cells are present. In prometamorphosis, the development of the first glandular rudiments without secretion production begins, also xanthophores. During metamorphosis, mucous glands differentiated before granular glands. Until late metamorphosis ciliated cells persist and epidermis changes to an adultlike. In adults, granular glands show polymorphism with different distributions in the body, despite not having macroglandular structures. In addition, P. ephippifer individuals have few epidermal projections and cryptic coloration. Our results show that despite sharing a few morphological structures with other specimens of the Leiuperinae subfamily, the characteristics present in individuals of P. ephippifer are appropriate to the niche occupied and consistent with the changes that occur throughout their lineage.
... Specimens of P. ephippifer in premetamorphosis and most of prometamorphosis exhibit only a stratum corneum and stratum germinativum composing the epidermis, where a stratum compactum forms the dermis. This is different from other specimens of the Hylidae (Lacombe et al. 2000) and Bufonidae (Regueira et al. 2016) which can present thinner and thicker epidermal layers, respectively, during the same developmental phase. The thickness of these layers can also vary according to the body region and between the developmental stages (Fabrezi et al. 2010;Chammas et al. 2015). ...
Throughout metamorphic development until adulthood, amphibians have important integumentary adaptations that maintain their physiological needs and protection against predation. The evolution of these strategies in the subfamily Leiuperinae has been elucidated in recent years. Therefore, the knowledge about Physalaemus ephippifer’s skin attributes can corroborate the changes of these characteristics in the clade. The aim of this study was to assess the characteristics of P. ephippifer regarding the morphological development the skin during their lifespan. We collected foam nests in temporary ponds as well as adult individuals in a forest fragment. In the laboratory, the animals were classified by stage development, euthanized, and fixed. Sections of the dorsolateral, lumbar, and femoral portions were dissected from the adult individuals. Samples were submitted to histological processing for light microscopy and scanning electron microscopy. In premetamorphosis phase, gland development is absent and secretory cells are present. In prometamorphosis, development of first glandular rudiments without secretion production begins, also xanthophores. During metamorphosis, mucous glands differentiated before serous glands. Until late metamorphosis ciliated cells persist and epidermis changes to an adultlike. In adults, serous glands show polymorphism with different distributions in the body, despite not having macroglandular structures. In addition, P. ephippifer individuals have few epidermal projections and cryptic coloration. Our results show that despite sharing few morphological structures with other specimens of Leiuperinae subfamily, the characteristics present in individuals of P. ephippifer are appropriate to the niche occupied and consistent with the changes that occur throughout their lineage.
... Skin glands move from the epidermis to the dermis during the terrestrial juvenile phase [7]. It has been reported that [49] Phyllomedusa bicolor tadpoles had mucous and granular glands; however, the gland duct was not developed until metamorphosis. Granular glands of amphibian skin may not be able to excrete antimicrobial peptides fully on the skin surface until development of the neuromuscular secretory mechanism and gland ducts in the epidermis [50]. ...
Amphibian skin is a particularly complex organ that is primarily responsible for respiration, osmoregulation, thermoregulation, defense, water absorption, and communication. The skin, as well as many other organs in the amphibian body, has undergone the most extensive rearrangement in the adaptation from water to land. Structural and physiological features of skin in amphibians are presented within this review. We aim to procure extensive and updated information on the evolutionary history of amphibians and their transition from water to land—that is, the changes seen in their skin from the larval stages to adulthood from the points of morphology, physiology, and immunology.
... Their secretions play an essential role in aiding cutaneous respiration, reproduction, defense against predators, as well as defense against desiccation and proliferation of microorganisms (Toledo and Jared, 1995). Lacombe et al. (2000) conducted an ultrastructural study that characterized the skin of the species of Phyllomedusa according Frontiers in Pharmacology frontiersin.org 06 to size and activity, and presented a profile of skin glands composed of three types of cutaneous glands: lipid, mucous, and serous ( Figure 4). ...
... Mucous glands are mainly distributed in the ventral region and are practically absent from the back. These produce mucus to assist the cutaneous physiological functions such as respiration, reproduction, defense and thermoregulation (Toledo and Jared, 1995;Lacombe et al., 2000). Serous glands are the largest and are distributed all over the body; however, they are prominent in the dorsolateral region, and behind the eyes, and form the parotid glands . ...
... Serous glands are the largest and are distributed all over the body; however, they are prominent in the dorsolateral region, and behind the eyes, and form the parotid glands . These glands are primarily responsible for passive defense and are the first to develop, although the gland duct lengthens according to the maturation of the epidermis, and opens to the skin surface once they reach metamorphosis (Toledo and Jared, 1995;Lacombe et al., 2000). According to Lacombe et al. (2000), there are two classes of serous glands, type I and II. ...
Phyllomedusa bicolor (Phyllomedusidae), popularly known as the kambô in Brazil, is a tree frog that is widely distributed in South American countries and is known for producing a skin secretion that is rich in bioactive peptides, which are often used in indigenous rituals. The biological effects of the skin secretion were observed in the first studies with indigenous communities. Over the last six decades, researchers have been studying the chemical composition in detail, as well as the potential pharmacological applications of its constituents. For this reason, indigenous communities and health agents fear the misuse of the kambô, or the inappropriate use of the species, which can result in health complications or even death of users. This article seeks to provide a transdisciplinary review that integrates knowledge regarding the biology of P. bicolor, ethnoknowledge about the ritual of the kambô, and the chemistry and pharmacology of the skin secretion of this species, in addition to medical aspects of the indiscriminate use of the kambô. Furthermore, this review seeks to shed light on perspectives on the future of research related to the kambô.
... Since then, various polypeptides present in amphibian extracts have been examined and studied by the research group of Prof. Erspamer, both their biochemical composition and their pharmacological and biological properties through animal experiments [28]. Subsequently, using immunohistochemistry and electron microscopy, Lacombe et al. identified the presence of three different types of glands on the frog's skin, each of which is capable of producing different substances with biological properties [29]. ...
Kambo is the name of a natural substance derived from the glandular secretions of the amphibian Phyllomedusa bicolor, a species native to regions in South America. The communities living in these areas administer the substance generally transdermally during rituals for religious-purifying purposes, producing small skin burns. The scientific literature has reported some cases of intoxication following the use of Kambo but this aspect is still poorly understood. In fact, no shared therapy protocols exist for these events nor any real legislation on Kambo. The purpose of this work was to examine all cases of acute intoxication resulting from the administration of Kambo and published over the last 10 years, illustrating clinical signs, laboratory findings, instrumental tests, and therapy. The several cases identified in our review confirm that acute Kambo intoxication can occur, with serious and life-threatening effects. We developed a protocol aimed at the early diagnosis of cases of suspected acute intoxication by creating a treatment algorithm. The study aims to investigate the pathophysiology of these events in humans, proposing a protocol for the diagnosis and treatment of these cases that can be used by healthcare professionals.
... The broad range of small (700-4600 Da) 14 biogenic peptides identified in the secretions of various cutaneous glands in frogs of the Hylidae family, including Phyllomedusa bicolor are believed to provide the frogs with defenses against predators in their natural habitat. 2,[14][15][16][17] Much of the existing literature describes these amphibian peptides in reference to several frog species or families within the Phyllomedusae genus and other genera in the Hylidae frog family. Very few papers comprehensively present information that is species-specific to the Phyllomedusa bicolor frog in the context of peptide exposure from Kambô. ...
... Structurally similar to dermorphins, deltorphins are also 7-residue opioid peptides with a high affinity and selectivity for δ-opioid receptors in mammals. 17,19 Deltorphin I was found in one study to be present in the dried Kambô secretion at a concentration of 5.31 µg/mg. 2 In rats, deltorphins have been observed to increase motor activity (locomotion, sniffing, and rearing) and induce behavioral changes (increased social contacts) in a dosedependent manner. 50 Deltorphin II has also been found to increase extracellular dopamine concentrations and activity at D 1 receptor sites in the rat nucleus accumbens (NA). ...
... 57 DRS form part of a family of broad-spectrum antimicrobial peptides involved in the defense of the Kambô frogs' skin against bacterial invasion. 17,58,59 Dermaseptin-Bs (DRS-B) are the family of naturally occurring DRS that are found specifically in Phyllomedusa bicolor. Nine DRS-B varieties have been identified in P. bicolor, ( Table 2) indicated by tagging with the letter B. 57 Some non-homologous peptides derived from P. bicolor that are categorized in the DRS family include phylloxin-B1, plasticin-B1, and phylloseptin-B1. ...
Kambô is an Amazonian ritual which includes the application of the defensive secretion of the Phyllomedusa bicolor frog to superficial burns made on the skin of human participants. The secretion, which contains a range of biologically active linear peptides, induces a short purgative experience that is extensively reported by participants to leave them with positive physical, emotional and spiritual after-effects. Various peptides identified in the secretion exert analgesic, vascular, and gastric effects in vivo, and antimicrobial and anti-cancer effects, among others, in vitro. While there has been some investigation into the physiological effects of various individual peptides isolated from the P. bicolor secretion, very little is known about the putative synergistic effects of concurrent administration of the complete substance through the transdermal methods used traditionally in the Kambô ritual. In this review and commentary, the authors summarize the existing biological information from animal research on peptides from the P. bicolor secretion, then consider the evidence in the context of Kambô administration to humans. The presented information suggests that specific peptides are likely to contribute to analogous physiological effects of Kambô in humans. The possibility that beyond their physiological action, the experiential or phenomenological component of these effects may have therapeutic applications is discussed, concluding with a consideration of the feasibility of human clinical research.
... The knowledge available regarding the occurrence of AMP synthesis in larval anurans is limited and controversial. Skin-associated granular glands and their ducts are mostly immature before metamorphosis in most species [41,42], suggesting no, or limited AMP production (but see [43]). However, at the same time, gland products may also be secreted by a merocrine process, where the secretum reaches the skin surface via exocytosis directly or through the epidermal interstitium [41,44,45]. ...
Background:
Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis, one of the major causes of worldwide amphibian biodiversity loss. Many amphibians exhibit skin-based chemical defences, which may play an important role against invading pathogens, but whether the synthesis of these chemical compounds is enhanced or suppressed in the presence of pathogens is largely unknown. Here we investigated direct and indirect effects of larval exposure to the globally distributed and highly virulent Bd-GPL strain on skin secreted chemical defences and life history traits during early ontogeny of agile frogs (Rana dalmatina) and common toads (Bufo bufo).
Results:
Exposure to Bd during the larval stage did not result in enhanced synthesis of the antimicrobial peptide Brevinin-1 Da in R. dalmatina tadpoles or in increased production of bufadienolides in B. bufo tadpoles. However, exposure to Bd during the larval stage had a carry-over effect reaching beyond metamorphosis: both R. dalmatina and B. bufo froglets contained smaller quantities of defensive chemicals than their Bd-naïve conspecifics in the control treatment. Prevalence of Bd and infection intensities were very low in both larvae and metamorphs of R. dalmatina, while in B. bufo we observed high Bd prevalence and infection intensities, especially in metamorphs. At the same time, we did not find a significant effect of Bd-exposure on body mass or development rate in larvae or metamorphs in either species.
Conclusions:
The lack of detrimental effect of Bd-exposure on life history traits, even parallel with high infection intensities in the case of B. bufo individuals, is surprising and suggests high tolerance of local populations of these two species against Bd. However, the lowered quantity of defensive chemicals may compromise antimicrobial and antipredatory defences of froglets, which may ultimately contribute to population declines also in the absence of conspicuous mass-mortality events.
... This type of secretion also delivers cytoplasm, cellular organelles and nuclear cell products into the lumen of the gland, including mRNA [50,51,54,67]. These types of glands can be found in the venom glands of cone snails, certain spider species and teleost fish (Fig 3, Table 1) [59,60,[68][69][70][71][72][73][74][75][76][77]. Spiders utilise both apocrine and holocrine secretion mechanisms, depending on the species [13,60,61,78]. ...
... Although this study focused on venom gland secretions primarily, poisonous animal lineages with apocrine or holocrine secretion methods (e.g., amphibians) might be similarly harnessed to generate the transcriptome of genome-derived compounds (i.e. proteins and peptides) in the poison glands [74][75][76][77]100]. Table. ...
Scorpion venoms are mixtures of proteins, peptides and small molecular compounds with high specificity for ion channels and are therefore considered to be promising candidates in the venoms-to-drugs pipeline. Transcriptomes are important tools for studying the composition and expression of scorpion venom. Unfortunately, studying the venom gland transcriptome traditionally requires sacrificing the animal and therefore is always a single snapshot in time. This paper describes a new way of generating a scorpion venom gland transcriptome without sacrificing the animal, thereby allowing the study of the transcriptome at various time points within a single individual. By comparing these venom-derived transcriptomes to the traditional whole-telson transcriptomes we show that the relative expression levels of the major toxin classes are similar. We further performed a multi-day extraction using our proposed method to show the possibility of doing a multiple time point transcriptome analysis. This allows for the study of patterns of toxin gene activation over time a single individual, and allows assessment of the effects of diet, season and other factors that are known or likely to influence intraindividual venom composition. We discuss the gland characteristics that may allow this method to be successful in scorpions and provide a review of other venomous taxa to which this method may potentially be successfully applied.
... More than a hundred active peptides have been isolated from the skins of these frogs to date. [2][3][4] The mechanisms of action of the P bicolor secretions are not completely understood; a number of cytotoxic effects on different cell types have been identified. 5,6 In addition, some of the toxins dilate blood vessels and increase the permeability of the blood-brain barrier. ...
... Granular glands are composed of a syncytial structure that secretes variable protein products and depending on the species, also produce amines, alkaloids, and bufadienolides Trueb 1994, Sciani et al. 2013). Some species, particularly some arboreal species, possess lipid glands, which seem to function in the prevention of water loss (Lacombe et al. 2000, Felsemburgh et al. 2007. ...
The anuran skin characteristically has different types of glands, most of which are microscopic and are spread throughout the skin. Some species have specialized regions where glands agglomerate, forming macroglands. The description of the external morphology of Ololygoncentralis (Pombal & Bastos, 1996) revealed the presence of an inguinal gland. Ololygoncentralis is the only species of the genus that has a macrogland. The present study found these inguinal macroglands to be present only on male specimens, thus characterizing it as a sexually dimorphic skin gland. Microscopic analysis revealed that these glands are composed of many syncytial units involved by myoepithelial cells. The center of the syncytium is full of a proteinaceous secretion with a basic pH and the absence of sugar residues. Similar glands observed in other anuran species have been associated with pheromone production, suggesting that the inguinal glands described for O.centralis males may have a similar function.
