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1.
Fish Shellfish Immunol ; 60: 502-508, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27840170

RESUMEN

Intestine mast cells/eosinophilic granule cells (MCs/EGC) of the marine species Centropomus parallelus (fat snook) were first studied using light and electron microscopy techniques. Mast cells are cells from the connective tissue found in almost all organs and tissues of vertebrates. In fish, they appear in greater numbers in parts of their bodies that are exposed to their environment, such as skin, gills and intestine. The granules in fat snook's mast cell contain a variety of substances, such as histamine, heparin, chondroitin sulfate, serotonin, proteases and cytokines. The present study of intestine MCs/EGC was carried out in 20 specimens of fat snook. Samples of tissue were fixed in Bouin solution and in buffered formalin. Ferric hematoxylin - Congo red, pH6 acridine orange, pH2.5 and pH0,5 Alcian Blue (AB), toluidine blue, PAS, AB + PAS and immunohistochemistry protocols were used. In the mucosa and submucosa layers, MCs/EGCs granules with basic contents were evidenced by Congo red staining, and with acid contents granules were identified through pH 2.5 and 0,5 AB, and acridine orange. Basic and acid contents were simultaneously evidenced using ferric hematoxylin - Congo red stain. Metachromasia was observed in both mucosal and submucosal mast cells. Neutral glycoproteins were evidenced by using PAS protocol, glycosaminoglycan through AB and both simultaneously through AB + PAS. In immunohistochemistry assays, MCs/EGC were positive for tryptase, chymase and serotonin. As in mammals, the study of samples fixed in modified Karnovsky for transmission electron microscopy evidenced that most of the MCs granules were spherical and showed varying electron density, as described in previous reports on other teleost fish species. The metachromasia observed and the identification of tryptase, chymase and serotonin suggest a great similarity between fat snook's MCs/EGC and those described in the mucosa of mammals.


Asunto(s)
Eosinófilos/citología , Mastocitos/citología , Perciformes/inmunología , Animales , Eosinófilos/ultraestructura , Inmunohistoquímica/veterinaria , Intestinos/citología , Intestinos/ultraestructura , Mastocitos/ultraestructura , Microscopía Electrónica de Transmisión/veterinaria , Coloración y Etiquetado/veterinaria
2.
BMC Evol Biol ; 14: 58, 2014 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-24661572

RESUMEN

BACKGROUND: Efficient venom delivery systems are known to occur only in varanoid lizards and advanced colubroidean snakes among squamate reptiles. Although components of these venomous systems might have been present in a common ancestor, the two lineages independently evolved strikingly different venom gland systems. In snakes, venom is produced exclusively by serous glands in the upper jaw. Within the colubroidean radiation, lower jaw seromucous infralabial glands are known only in two distinct lineages-the basal pareatids and the more advanced Neotropical dipsadines known as "goo-eating snakes". Goo-eaters are a highly diversified, ecologically specialized clade that feeds exclusively on invertebrates (e.g., gastropod molluscs and annelids). Their evolutionary success has been attributed to their peculiar feeding strategies, which remain surprisingly poorly understood. More specifically, it has long been thought that the more derived Dipsadini genera Dipsas and Sibynomorphus use glandular toxins secreted by their infralabial glands to extract snails from their shells. RESULTS: Here, we report the presence in the tribe Dipsadini of a novel lower jaw protein-secreting delivery system effected by a gland that is not functionally related to adjacent teeth, but rather opens loosely on the oral epithelium near the tip of the mandible, suggesting that its secretion is not injected into the prey as a form of envenomation but rather helps control the mucus and assists in the ingestion of their highly viscous preys. A similar protein-secreting system is also present in the goo-eating genus Geophis and may share the same adaptive purpose as that hypothesized for Dipsadini. Our phylogenetic hypothesis suggests that the acquisition of a seromucous infralabial gland represents a uniquely derived trait of the goo-eating clade that evolved independently twice within the group as a functionally complex protein-secreting delivery system. CONCLUSIONS: The acquisition by snail-eating snakes of such a complex protein-secreting system suggests that the secretion from the hypertrophied infralabial glands of goo-eating snakes may have a fundamental role in mucus control and prey transport rather than envenomation of prey. Evolution of a functional secretory system that combines a solution for mucus control and transport of viscous preys is here thought to underlie the successful radiation of goo-eating snakes.


Asunto(s)
Evolución Biológica , Colubridae/fisiología , Glándulas Exocrinas/fisiología , Caracoles , Animales , Colubridae/anatomía & histología , Colubridae/clasificación , Colubridae/genética , Glándulas Exocrinas/anatomía & histología , Maxilares/anatomía & histología , Maxilares/fisiología , Filogenia , Proteínas/metabolismo , Reptiles/genética , Caracoles/química
3.
Science ; 383(6687): 1092-1095, 2024 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-38452082

RESUMEN

Among vertebrates, the yolk is commonly the only form of nutritional investment offered by the female to the embryo. Some species, however, have developed parental care behaviors associated with specialized food provisioning essential for offspring survival, such as the production of lipidic-rich parental milk in mammals. Here, we show that females of the egg-laying caecilian amphibian Siphonops annulatus provide similarly lipid-rich milk to altricial hatchlings during parental care. We observed that for 2 months, S. annulatus babies ingested milk released through the maternal vent seemingly in response to tactile and acoustic stimulation by the babies. The milk, composed mainly of lipids and carbohydrates, originates from the maternal oviduct epithelium's hypertrophied glands. Our data suggest lactation in this oviparous nonmammalian species and expand the knowledge of parental care and communication in caecilians.


Asunto(s)
Anfibios , Lactancia , Leche , Oviparidad , Animales , Femenino , Anfibios/fisiología , Leche/química , Oviductos/citología , Oviductos/fisiología , Oviparidad/fisiología , Tacto , Lípidos/análisis
4.
ScientificWorldJournal ; 2013: 937407, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23737734

RESUMEN

Amphibians are known by cutaneous glands, spread over the skin, containing toxins (proteins, peptides, biogenic amines, steroidal bufadienolides, and alkaloids) used as chemical defense against predators and microbial infection. Toads are characterized by the presence of parotoid macroglands. The common toads have lately been divided into two genera: Bufo (Europe, Asia, and Africa) and Rhinella (South America). Basal Rhaebo genus is exclusively of Central America and Amazon region. Although Rhinella and Rhaebo are related, species may share differences due to the diversity of environments that they live in. In this work, we have performed a biochemical characterization of the components of the poison of eight Rhinella species and one Rhaebo by means of RP-HPLC with either UV or MS detection and by SDS-PAGE, in order to verify whether phylogenetic and biological differences, such as habitat, diet, and defensive strategies, between them may also be reflected in poison composition. Although some components were common among the secretions, we were able to identify exclusive molecules to some species. The fact that closely related animals living in different habitats secrete different molecules into the skin is an indication that biological features, and not only evolution, seem to directly influence the skin secretion composition.


Asunto(s)
Alcaloides/metabolismo , Venenos de Anfibios/metabolismo , Bufonidae/clasificación , Bufonidae/metabolismo , Glándula Parótida/metabolismo , Esteroides/metabolismo , Animales , América del Sur , Especificidad de la Especie
5.
Nature ; 440(7086): 926-9, 2006 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-16612382

RESUMEN

Although the initial growth and development of most multicellular animals depends on the provision of yolk, there are many varied contrivances by which animals provide additional or alternative investment in their offspring. Providing offspring with additional nutrition should be favoured by natural selection when the consequent increased fitness of the young offsets any corresponding reduction in fecundity. Alternative forms of nutrition may allow parents to delay and potentially redirect their investment. Here we report a remarkable form of parental care and mechanism of parent-offspring nutrient transfer in a caecilian amphibian. Boulengerula taitanus is a direct-developing, oviparous caecilian, the skin of which is transformed in brooding females to provide a rich supply of nutrients for the developing offspring. Young animals are equipped with a specialized dentition, which they use to peel and eat the outer layer of their mother's modified skin. This new form of parental care provides a plausible intermediate stage in the evolution of viviparity in caecilians. At independence, offspring of viviparous and of oviparous dermatotrophic caecilians are relatively large despite being provided with relatively little yolk. The specialized dentition of skin-feeding (dermatophagous) caecilians may constitute a preadaptation to the fetal feeding on the oviduct lining of viviparous caecilians.


Asunto(s)
Anfibios/anatomía & histología , Anfibios/fisiología , Fenómenos Fisiológicos Nutricionales de los Animales , Ingestión de Alimentos/fisiología , Madres , Piel , Anfibios/crecimiento & desarrollo , Animales , Femenino , Oviparidad/fisiología , Selección Genética , Piel/anatomía & histología , Piel/citología , Diente/anatomía & histología , Diente/fisiología
6.
J Exp Zool A Ecol Integr Physiol ; 337(5): 537-546, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35201668

RESUMEN

Sequestration of chemical defenses from dietary sources is dependent on the availability of compounds in the environment and the mechanism of sequestration. Previous experiments have shown that sequestration efficiency varies among alkaloids in poison frogs, but little is known about the underlying mechanism. The aim of this study was to quantify the extent to which alkaloid sequestration and modification are dependent on alkaloid availability and/or sequestration mechanism. To do this, we administered different doses of histrionicotoxin (HTX) 235A and decahydroquinoline (DHQ) to captive-bred Adelphobates galactonotus and measured alkaloid quantity in muscle, kidney, liver, and feces. HTX 235A and DHQ were detected in all organs, whereas only DHQ was present in trace amounts in feces. For both liver and skin, the quantity of alkaloid accumulated increased at higher doses for both alkaloids. Accumulation efficiency in the skin increased at higher doses for HTX 235A but remained constant for DHQ. In contrast, the efficiency of HTX 235A accumulation in the liver was inversely related to dose and a similar, albeit statistically nonsignificant, pattern was observed for DHQ. We identified and quantified the N-methylation of DHQ in A. galactonotus, which represents a previously unknown example of alkaloid modification in poison frogs. Our study suggests that variation in alkaloid composition among individuals and species can result from differences in sequestration efficiency related to the type and amount of alkaloids available in the environment.


Asunto(s)
Alcaloides , Venenos , Alcaloides/química , Animales , Anuros/fisiología , Metilación , Quinolinas
7.
Fish Shellfish Immunol ; 31(4): 571-7, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21802518

RESUMEN

The cytochemical, immunocytochemical and ultrastructural characteristics of leukocytes and thrombocytes in the peripheral blood of the fat snook (Centropomus paralellus) - a fish occurring in Brazil - were investigated. The cytochemical methods were performed to demonstrate four enzymatic reactions - o-toluidine-hydrogen peroxide, naphtol AS-MX phosphate, naphtol AS-BI phosphate and alpha-naphtil acetate to detect myeloperoxidase (MPO), alkaline phosphatase (ALP), acid phosphatase (ACP) and non-specific esterase (α-NAE), respectively - and two non-enzymatic ones - Periodic-Acid Schiff (PAS) and Sudan black B (SBB) to detect the occurrence of glycogen and phospholipids, respectively. Immunocytochemical method utilizing polyclonal rabbit antibody against mammal metalloproteinases (MMPs) 2 and 9 were done. Standard method for Electron Microscopy (EM) was applied for the ultrastructural study. The cytochemical reactions were positive in neutrophils for MPO, ACP, α-NAE, glycogen and phospholipids; in lymphocytes for ACP and α-NAE; in monocytes for ACP and α-NAE and in thrombocytes for ACP, α-NAE and glycogen. Only neutrophils were positive for MMPs 2 and 9, and none of the cells studied were positive for ALP. Ultrastructurally: 1) neutrophil showed a spherical shape with a spherical, indented or lobulated euchromatic nucleus, and cytoplasm containing granules of varied sizes and mitochondria of varied shapes and sizes. The nucleus/cytoplasm relation and the size of granules suggest neutrophil maturation in peripheral blood; 2) lymphocytes showed partially heterochromatic nucleus and minimal cytoplasm; 3) monocytes had long cytoplasmic projections, an indented nucleus, evident nucleolus and cytoplasm with granules of varied sizes and vacuoles; 4) thrombocytes were predominantly elliptical or roughly spherical in shape, had a partially heterochromatic nucleus and cytoplasm containing electron-dense granules, intricate canalicular system and vacuoles occasionally holding phagocytic material.


Asunto(s)
Plaquetas/citología , Leucocitos/citología , Perciformes , Animales , Plaquetas/química , Plaquetas/inmunología , Plaquetas/ultraestructura , Brasil , Esterasas/sangre , Glucógeno/sangre , Inmunohistoquímica/veterinaria , Leucocitos/química , Leucocitos/inmunología , Leucocitos/ultraestructura , Metaloproteinasa 2 de la Matriz/sangre , Metaloproteinasa 9 de la Matriz/sangre , Microscopía Electrónica/veterinaria , Perciformes/inmunología , Peroxidasa/sangre , Fosfolípidos/sangre
8.
J Venom Anim Toxins Incl Trop Dis ; 27: e20200105, 2021 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-33868394

RESUMEN

BACKGROUND: Amphibians inhabit the terrestrial environment, a conquest achieved after several evolutionary steps, which were still insufficient to make them completely independent of the aquatic environment. These processes gave rise to many morphological and physiological changes, making their skin (and cutaneous secretion) rich in bioactive molecules. Among the tree frogs, the secretion is composed mainly of peptides; but alkaloids, proteins and steroids can also be found depending on the species. The most known class of biologically active molecules is the antimicrobial peptides (AMPs) that act against bacteria, fungi and protozoans. Although these molecules are well-studied among the hylids, AMPs ontogeny remains unknown. Therefore, we performed peptidomic and proteomic analyses of Pithecopus nordestinus (formerly Phyllomedusa nordestina) in order to evaluate the peptide content in post-metamorphosed juveniles and adult individuals. METHODS: Cutaneous secretion of both life stages of individuals was obtained and analyzed by LC-MS/MS after reduction and alkylation of disulfide bonds or reduction, alkylation and hydrolysis by trypsin. RESULTS: Differences in the TIC profile of juveniles and adults in both treatments were observed. Moreover, the proteomic data revealed known proteins and peptides, with slight differences in the composition, according to the life stage and the treatment. AMPs were identified, and bradykinin-potentiating peptides were observed in trypsin-treated samples, which suggests a protein source of such peptide (cryptide). CONCLUSION: In general, skin secretion contents were similar between juveniles and adults, varying in quantity, indicating that the different stages of life are reflected in the number of molecules and not on their diversity.

9.
Toxicon ; 53(3): 367-74, 2009 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-19105969

RESUMEN

Centipedes are widely distributed over all the continents. As they are well adapted to urban areas they can often cause accidents to humans by injecting venom produced in the glands located inside their maxillipeds. The fine morphology of the centipede venom glands is practically unknown. This present study is the first comparative report on the histology, histochemistry and ultrastructure of the venom glands of the centipede species responsible for the majority of accidents to humans in Brazil: Scolopendra viridicornis, Cryptops iheringi and Otostigmus pradoi. In all species the glands are basically composed of columnar secretory cells radially disposed side by side, individually opening through pores in a central chitinous duct. Each secretory cell is covered by striated muscular fibres. The secretion has the form of small PAS positive granules and large hyaline secretory bromophenol blue positive vacuoles, indicating the presence of neutral polysaccharides and protein. The secretion is conducted through the secretory cell necks to the pores, which open into the central chitinous duct. The results indicate a great similarity both in morphology and primary chemical composition of the venom among the studied species, except for the size of the glands, which is proportional to the body dimensions of each species.


Asunto(s)
Artrópodos/anatomía & histología , Glándulas Exocrinas/anatomía & histología , Anatomía Comparada , Animales , Venenos de Artrópodos , Brasil , Glándulas Exocrinas/ultraestructura , Microscopía Electrónica de Transmisión , Fotomicrografía , Especificidad de la Especie
10.
Protein J ; 38(1): 83-94, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30697667

RESUMEN

Amphibians are, currently, considered the first vertebrates that had performed the aquatic to terrestrial transition during evolution; therefore, water balance and dehydration control were prerequisites for such environment conquering. Among anurans, Phyllomedusa is a well-studied genus, due to its peptide-rich skin secretion. Here, we have analyzed the skin secretion of Phyllomedusa distincta targeting the proteins present in the skin secretion. The major soluble protein was chromatographically isolated and utilized to immunize rabbits. Through proteomics approaches, we were able to identify such protein as being the diacylglycerol O-acyltransferase 2 (DGAT2), a crucial enzyme involved in lipid synthesis and in the skin water balance. Immunohistochemistry assays revealed the protein tissular distribution for different animal species, belonging to different branches of the phylogenetic tree. Specifically, there was positivity to the anti-DGAT2 on Amphibians' skin, and no antibody recognition on fish and mammals' skins. The DGAT2 multiple sequence alignment reveals some degree of conservation throughout the genera; however, there is a different cysteine pattern among them. Molecular modeling analyses corroborate that the different cysteine pattern leads to distinct 3D structures, explaining the different antibody recognition. Moreover, the protein phylogenetic analyses place the Xenopus DGAT2 (the available amphibian representative) next to the Coelacanthus enzyme, which have led the authors to term this a 'paleo-protein'. DGAT2 would be, therefore, an ancient protein, crucial to the terrestrial environment conquest, with a unique folding-as indicated by the molecular models and immunohistochemistry analyses-a consequence of the different cysteine pattern but with conserved biological function.


Asunto(s)
Proteínas Anfibias/química , Diacilglicerol O-Acetiltransferasa/química , Evolución Molecular , Modelos Moleculares , Filogenia , Pliegue de Proteína , Proteínas Anfibias/genética , Animales , Anuros , Diacilglicerol O-Acetiltransferasa/genética
11.
Sci Rep ; 9(1): 5388, 2019 03 29.
Artículo en Inglés | MEDLINE | ID: mdl-30926879

RESUMEN

The phenomenon of fluorescence can be used by animals to change effective colouration or patterning, potentially to serve functions including intra- and interspecific signalling. Initially believed to be restricted to marine animals, fluorescent colours are now being described in an increasing number of terrestrial species. Here, we describe unique, highly fluorescent patterns in two species of pumpkin toadlets (Brachycephalus ephippium and B. pitanga). We establish that the origin of the fluorescence lies in the dermal bone of the head and back, visible through a particularly thin skin. By comparing them to those of the closely related species Ischnocnema parva, we demonstrate that pumpkin toadlets' bones are exceptionally fluorescent. We characterize the luminescence properties of the toadlets' bones and discuss the potential function of fluorescent patterns in natural lighting conditions.


Asunto(s)
Anuros/metabolismo , Animales , Anuros/anatomía & histología , Fluorescencia , Especificidad de la Especie
12.
Biomed Res Int ; 2018: 1032638, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29955598

RESUMEN

Bufotenine is an alkaloid derived from serotonin, structurally similar to LSD and psilocin. This molecule is able to inhibit the rabies virus infection in in vitro and in vivo models, increasing the survival rate of infected animals. Being a very promising molecule for an incurable disease and because of the fact that there is no consensus regarding its neurological effects, this study aimed to evaluate chronic treatment of bufotenine on behavior, pathophysiology, and pharmacokinetics of mice. Animals were daily treated for 21 consecutive days with 0.63, 1.05, and 2.1 mg/animal/day bufotenine and evaluated by open field test and physiological parameters during all the experiment. After this period, organs were collected for histopathological and biodistribution analysis. Animals treated with bufotenine had mild behavioral alterations compared to the control group, being dose-response relationship. On the other hand, animals showed normal physiological functions and no histological alterations in the organs. With high doses, an inflammatory reaction was observed in the site of injection, but with no cellular damage. The alkaloid could be found in the heart and kidney with all doses and in the lungs and brain with higher doses. These results show that the effective dose, 0.63 mg/day, is safe to be administered in mice, since it did not cause significant effects on the animals' physiology and on the CNS. Higher doses were well tolerated, causing only mild behavioral effects. Thus, bufotenine might be a drug prototype for rabies treatment, an incurable disease.


Asunto(s)
Bufotenina/farmacocinética , Antagonistas de la Serotonina/farmacocinética , Animales , Femenino , Masculino , Ratones , Serotonina , Distribución Tisular
13.
Peptides ; 28(3): 515-23, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17098329

RESUMEN

Bradykinin potentiating peptides (BPPs) from Bothrops jararaca venom were first described in the middle of 1960s and were the first natural inhibitors of the angiotensin-converting enzyme (ACE). BPPs present a classical motif and can be recognized by their typical pyroglutamyl (Pyr)/proline rich sequences presenting, invariably, a proline residue at the C-terminus. In the present study, we describe the isolation and biological characterization of a novel BPP isolated from the skin secretion of the Brazilian tree-frog Phyllomedusa hypochondrialis. This new BPP, named Phypo Xa presents the sequence Pyr-Phe-Arg-Pro-Ser-Tyr-Gln-Ile-Pro-Pro and is able to potentiate bradykinin activities in vivo and in vitro, as well as efficiently and competitively inhibit ACE. This is the first canonical BPP (i.e. Pyr-Aaa(n)-Gln-Ile-Pro-Pro) to be found not only in the frog skin but also in any other natural source other than the snake venoms.


Asunto(s)
Anuros/metabolismo , Bradiquinina/metabolismo , Oligopéptidos/aislamiento & purificación , Secuencia de Aminoácidos , Inhibidores de la Enzima Convertidora de Angiotensina/aislamiento & purificación , Inhibidores de la Enzima Convertidora de Angiotensina/metabolismo , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Animales , Anuros/genética , Presión Sanguínea/efectos de los fármacos , Bradiquinina/farmacología , Sinergismo Farmacológico , Femenino , Cobayas , Íleon/efectos de los fármacos , Técnicas In Vitro , Masculino , Oligopéptidos/genética , Oligopéptidos/metabolismo , Oligopéptidos/farmacología , Ratas , Ratas Wistar , Piel/metabolismo
14.
Toxicon ; 49(7): 1054-62, 2007 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-17306319

RESUMEN

Amphibian skin secretions contain several bioactive compounds such as biogenic amines, alkaloids, steroids, proteins and peptides; being peptides a continuously growing field of interest. This work aims to describe the main physiopathological properties of the tree frog Phyllomedusa hypochondrialis skin secretion, obtained by manual stimulation of the dorsal skin surface. Intravenous skin secretion administration provoked lethal effect in mice after 5min. Low doses induced significant systemic and local effects like edema and nociception in mice and topic administration induced myonecrosis in the endothelium of cremaster mice. The presence of phospholipase A(2) activity, proteolytic activity and creatine kinase activity (in the plasma of treated mice) are reported and are very likely to be related to the physiopathological (edematic and myotoxic) activities observed. These data provide in vivo evidence of the complex toxic effects of the P. hypochondrialis skin secretion as well as possible mechanisms of action for these effects.


Asunto(s)
Venenos de Anfibios/toxicidad , Anuros/metabolismo , Venenos de Anfibios/química , Venenos de Anfibios/metabolismo , Animales , Permeabilidad Capilar/efectos de los fármacos , Creatina Quinasa/sangre , Edema/inducido químicamente , Activación Enzimática/efectos de los fármacos , Ratones , Músculos/efectos de los fármacos , Músculos/patología , Dimensión del Dolor , Péptido Hidrolasas/metabolismo , Fosfolipasas A/sangre , Piel/metabolismo
15.
Toxicon ; 49(5): 625-33, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-17157344

RESUMEN

Phyllomedusa hypochondrialis skin secretion can cause both systemic and local effects. In this study, we describe the pattern of local acute inflammatory response after P. hypochondrialis skin secretion injection. The inflammatory reaction in the mice footpad was analysed, including the leukocyte recruitment into local tissue from the peripheral blood, in a mouse model of tissue injury. We also investigated the release of the cytokines IL-1, IL-6 and TNF-alpha, chemokines KC and MCP-1 and the eicosanoids LTB 4 and PGE(2) in mice. The present findings support the ability of P. hypochondrialis skin secretion to induce local inflammation. In addition, these skin secretion components play a role in the initial rolling and slowing of recruited leukocytes and the transition from rolling to adhesion. Levels of the proinflammatory cytokine IL-6, chemokines KC and MCP-1 as well as the eicosanoid PGE(2) were significantly increased after injection of a skin secretion of P. hypochondrialis (0.6 microg/30 microl intraplantar), whereas no changes in other parameters were observed. Finally, the mechanisms involved in the local inflammatory process induced by P. hypochondrialis skin secretion is one of the questions of relevance related to the complex pathophysiology induced by this particular secretion and other toxins.


Asunto(s)
Anuros , Secreciones Corporales/inmunología , Inflamación/inducido químicamente , Leucocitos/efectos de los fármacos , Piel/metabolismo , Análisis de Varianza , Animales , Adhesión Celular/efectos de los fármacos , Citocinas/inmunología , Citocinas/metabolismo , Ensayo de Inmunoadsorción Enzimática , Leucocitos/inmunología , Ratones , Microcirculación/efectos de los fármacos , Músculo Esquelético/irrigación sanguínea
16.
Toxicon ; 50(5): 688-97, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17659760

RESUMEN

Marine and freshwater stingrays are characterized by the presence of one to three mineralized serrated stingers on the tail, which are covered by epidermal cells secreting venom. When these animals are dorsally touched, the stinger can be introduced into the aggressor by a whip reflex mechanism of the tail, causing severe mechanical injuries and inoculating the venom. Accidents in humans are frequent causing intense local pain, oedema and erythema. Bacterial secondary infection is also common. In addition, injuries involving freshwater stingrays frequently cause a persistent cutaneous necrosis. The exact localization of the venom secretory epidermal cells in the stinger is controversial, but it is known that it is preferentially located in the ventrolateral grooves. A comparative morphological analysis of the stinger epidermal tissue of different marine and freshwater Brazilian stingray species was carried out. The results indicate that in freshwater species there is a larger number of protein secretory cells, of two different types, spread over the whole stinger epidermis, while in marine species the protein secretory cells are located only around or inside the stinger ventrolateral grooves. These differences between the stingers of the two groups can justify the more severe envenomation accidents with the freshwater species when compared with the marine species.


Asunto(s)
Mordeduras y Picaduras , Células Epidérmicas , Venenos de los Peces/metabolismo , Peces Venenosos , Rajidae/anatomía & histología , Animales , Brasil , Epidermis/metabolismo , Epidermis/ultraestructura , Glándulas Exocrinas/anatomía & histología , Glándulas Exocrinas/metabolismo , Agua Dulce , Agua de Mar , Rajidae/fisiología , Especificidad de la Especie
17.
J Morphol ; 268(7): 636-48, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17458886

RESUMEN

Many lizards have epidermal glands in the cloacal or femoral region with semiochemical function related to sexual behavior and/or territorial demarcation. Externally, these glands are recognized as a row of pores, opening individually in the center of a modified scale. In many species the pores are used as systematic characters. They form a glandular cord or, in some species, a row of glandular beads below the dermis, and are connected to the exterior through the ducts, which continuously liberate a solid secretion. Dead cells, desquamated from the secretory epithelium, constitute the secretion, known as "a secretion plug." The present work focuses on the morphology of the femoral glands of the teiid lizard Ameiva ameiva, correlating it to the way in which the secretion is deposited in the environment. The results here obtained are compared to those available for other lizards and amphisbaenians. We observed that the diameter of the glandular pores did not show significant differences between males and females. The glands comprise germinative and secretory cells, which pass through at least three stages of differentiation, during which an accumulation of cytoplasmic granules, with a glycoprotein content, occurs. The cells eventually die and desquamate from the secretory epithelium, forming a secretory plug mostly constituted by juxtaposed nonfragmented secretory cells. Because of the arrangement of the rosette-like scales surrounding the femoral pores, we suggest that when the animal is in a resting position, with its femoral regions touching the ground, these scales may be involved in the breakage of their respective plugs, depositing tiny portions on the substrate. In this manner, it seems that the method for signal dispersion in this species involves specifically adapted structures and does not simply involve the chance breakage of the plug, as the gland secretes it. Signal dispersion must also be intimately associated with the animal's movement within its territory.


Asunto(s)
Epidermis/ultraestructura , Lagartos/anatomía & histología , Glándulas Odoríferas/ultraestructura , Animales , Epidermis/metabolismo , Lagartos/metabolismo , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Feromonas/metabolismo , Glándulas Odoríferas/anatomía & histología , Glándulas Odoríferas/metabolismo
18.
Toxicon ; 137: 128-134, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28760510

RESUMEN

Toads have a pair of glandular accumulations on each side of the dorsal region of the head known as parotoid macroglands. These macroglands consist of secretory units (granular glands), each one capped with an epithelial plug. When threatened, toads point one of the parotoids toward the aggressor, and if the aggressor squeezes the parotoid with its teeth, jets of poison will come out of the secretory units and hit the predator's oral mucosa, thereby causing poisoning. Our study focused on the mechanism of parotoid function by comparing parotoids from toads naturally attacked by dogs with those manually compressed. We verified that the process of glandular emptying in response to dog bites is very similar to that following manual compression. We observed that the structure of the plug plays an essential role in the release of the poison jets. Our results suggest that the parotoids may act as "bulletproof vests," reducing the impact of the force exerted by predator attacks, and thus may function as a passive antipredator mechanism.


Asunto(s)
Bufonidae/fisiología , Glándulas Exocrinas/metabolismo , Venenos de Anfibios/metabolismo , Animales , Bufonidae/anatomía & histología , Perros , Conducta Predatoria
19.
Sci Rep ; 7(1): 12121, 2017 09 21.
Artículo en Inglés | MEDLINE | ID: mdl-28935936

RESUMEN

The emergence and maintenance of animal communication systems requires the co-evolution of signal and receiver. Frogs and toads rely heavily on acoustic communication for coordinating reproduction and typically have ears tuned to the dominant frequency of their vocalizations, allowing discrimination from background noise and heterospecific calls. However, we present here evidence that two anurans, Brachycephalus ephippium and B. pitanga, are insensitive to the sound of their own calls. Both species produce advertisement calls outside their hearing sensitivity range and their inner ears are partly undeveloped, which accounts for their lack of high-frequency sensitivity. If unheard by the intended receivers, calls are not beneficial to the emitter and should be selected against because of the costs associated with signal production. We suggest that protection against predators conferred by their high toxicity might help to explain why calling has not yet disappeared, and that visual communication may have replaced auditory in these colourful, diurnal frogs.


Asunto(s)
Anuros/fisiología , Vocalización Animal , Acústica , Animales , Anuros/anatomía & histología , Oído/anatomía & histología , Oído/fisiología , Femenino , Audición , Masculino , Modelos Anatómicos , Sonido
20.
Peptides ; 27(12): 3092-9, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16963159

RESUMEN

Amphibian antimicrobial peptides have been known for many decades and several of them have been isolated from anuran species. Dermaseptins are among the most studied antimicrobial peptides and are found in the skin secretion of tree frogs from the Phyllomedusinae subfamily. These peptides exert a lytic action on bacteria, protozoa, yeast, and filamentous fungi at micromolar concentrations, but unlike polylysines, present little hemolytic activity. In this work, two antimicrobial peptides were isolated from the crude skin secretion of Phyllomedusa hypochondrialis and tested against Gram-positive and Gram-negative bacteria, presenting no hemolytic activity at the tested concentrations. One of them was identified with the recently reported peptide PS-7 belonging to the phylloseptin family, and another was a novel peptide, named DPh-1, which was fully purified, sequenced by 'de novo' mass spectrometry and grouped into Dermaseptins (DPh-1).


Asunto(s)
Péptidos Catiónicos Antimicrobianos/química , Péptidos Catiónicos Antimicrobianos/metabolismo , Piel/química , Piel/metabolismo , Secuencia de Aminoácidos , Animales , Péptidos Catiónicos Antimicrobianos/genética , Péptidos Catiónicos Antimicrobianos/aislamiento & purificación , Anuros , Datos de Secuencia Molecular
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