Differences and Similarities among Parotoid Macrogland Secretions in South American Toads: A Preliminary Biochemical Delineation

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

Morphological Evidence for an Oral Venom System in Caecilian Amphibians

Amphibians are known for their skin rich in glands containing toxins employed in passive chemical defense against predators, different from, for example, snakes that have active chemical defense, injecting their venom into the prey. Caecilians (Amphibia, Gymnophiona) are snake-shaped animals with fossorial habits, considered one of the least known vertebrate groups. We show here that amphibian caecilians, including species from the basal groups, besides having cutaneous poisonous glands as other amphibians do, possess specific glands at the base of the teeth that produce enzymes commonly found in venoms. Our analysis of the origin of these glands shows that they originate from the same tissue that gives rise to teeth, similar to the venom glands in reptiles. We speculate that caecilians might have independently developed mechanisms of production and injection of toxins early in their evolutionary history

Variations in Tetrodotoxin Levels in Populations of Taricha granulosa are Expressed in the Morphology of Their Cutaneous Glands

Tetrodotoxin (TTX), one of the most toxic substances in nature, is present in bacteria, invertebrates, fishes, and amphibians. Marine organisms seem to bioaccumulate TTX from their food or acquire it from symbiotic bacteria, but its origin in amphibians is unclear. Taricha granulosa can exhibit high TTX levels, presumably concentrated in skin poison glands, acting as an agent of selection upon predatory garter snakes (Thamnophis). This co-evolutionary arms race induces variation in T. granulosa TTX levels, from very high to undetectable. Using morphology and biochemistry, we investigated differences in toxin localization and quality between two populations at the extremes of toxicity. TTX concentration within poison glands is related to the volume of a single cell type in which TTX occurs exclusively in distinctive secretory granules, suggesting a relationship between granule structure and chemical composition. TTX was detected in mucous glands in both populations, contradicting the general understanding that these glands do not secrete defensive chemicals and expanding currently held interpretations of amphibian skin gland functionality. Skin secretions of the two populations differed in low-mass molecules and proteins. Our results demonstrate that interpopulation variation in TTX levels is related to poison gland morphology

Amblyomin-X induces ER stress, mitochondrial dysfunction, and caspase activation in human melanoma and pancreatic tumor cell

During the last two decades, new insights into proteasome function and its role in several human diseases made it a potential therapeutic target. In this context, Amblyomin-X is a Kunitz-type FXa inhibitor similar to endogenous tissue factor pathway inhibitor (TFPI) and is a novel proteasome inhibitor. Herein, we have demonstrated Amblyomin-X cytotoxicity to different tumor cells lines such as pancreatic (Panc1, AsPC1BxPC3) and melanoma (SK-MEL-5 and SK-MEL-28). Of note, Amblyomin-X was not cytotoxic to normal human fibroblast cells. In addition, Amblyomin-X promoted accumulation of ER stress markers (GRP78 and GADD153) in sensitive (SK-MEL-28) and bortezomib-resistant (Mia-PaCa-2) tumor cells. The intracellular calcium concentration [Ca2+] (i) was slightly modulated in human tumor cells (SK-MEL-28 and Mia-PaCa-2) after 24 h of Amblyomin-X treatment. Furthermore, Amblyomin-X induced mitochondrial dysfunction, cytochrome-c release, PARP cleavage, and activation of caspase cascade in both human tumor (SK-MEL-28 and Mia-PaCa-2) cells. These investigations might help in further understanding of the antitumor properties of Amblyomin-X.Sao Paulo Research Foundation (FAPESP)National Council of Technological and Scientific Development (CNPq, INCTTox)Coordination of Improvement of Higher Education Personnel (CAPES)Uniao Quimica Farmaceutica NacionalButantan Inst, Biochem & Biophys Lab, Ave Vital Brazil 1500, BR-05503900 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Biochem, Sao Paulo, SP, BrazilUniv Sao Paulo, Inst Chem, Dept Biochem, Sao Paulo, BrazilUniv Sao Paulo, Sch Med, Expt Oncol Med Invest Lab, LIM 24, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Biochem, Sao Paulo, SP, BrazilFAPESP: 2010/52669-3FAPESP: 2010/07958-7FAPESP: 2011/05969-4FAPESP: CAT/CEPID 1998/14307-9FAPESP: CETICs 2013/07467-1Web of Scienc

Skin Gland Concentrations Adapted to Different Evolutionary Pressures in The Head and Posterior Regions of The Caecilian Siphonops Annulatus

Amphibian skin is rich in mucous glands and poison glands, secreting substances important for gas exchange and playing a fundamental role in chemical defense against predators and microorganisms. In the caecilian Siphonops annulatus (Mikan, 1920) we observed a concentration of enlarged mucous glands in the head region. In the posterior region of the body a similar concentration is made up of enlarged poison glands. These accumulations of glands structurally resemble the macroglands previously reported in anurans and salamanders. The skin glands in these regions are each surrounded by collagen walls forming a honeycomb-like structure. The collagen network in the head region firmly attaches to tiny pits in the bones of the skull. The two extremities of the body produce different secretions, containing exclusive molecules. Considering the fossorial lifestyle of caecilians, it seems evident that the secretions of the head and caudal region serve different functions. The anterior macrogland of mucous glands, rich in mucous/lipid secretion, in conjunction with the funnel-shaped head, may act to lubricate the body and penetrate the soil, thus facilitating locomotion underground. The blunt posterior end bearing an internalized macrogland of poison glands in the dermis may act in chemical defense and/or by blocking invasion of tunnels

Toxinologic studies about Echinometra lucunter sea urchin.

Echinometra lucunter, o ouriço-do-mar responsável por 50% dos acidentes por animais marinhos, causa inflamação e dor quando os espinhos entram na pele, efeitos atribuídos ao trauma mecânico, além de acidentes por ingestão de ovas. O líquido celômico e o extrato aquoso de espinhos foram fracionados e purificados até a obtenção de moléculas puras, que foram testadas em modelos de inflamação. Foram feitas análises histológicas do espinho e de atividade enzimática do extrato de espinho. Foi isolada uma molécula do espinho e um peptídeo do líquido celômico, que causaram inflamação e dor. Foi verificada atividade enzimática de catepsina B/X. Foi observada uma estrutura histológica organizada no espinho, com células entre a porção calcificada, algumas contendo grânulos eletrodensos com conteúdo protéico, típicas secretoras. Conclui-se que o espinho e o líquido celômico de E. lucunter possuem toxinas inflamatórias, que participam do envenenamento e o espinho tem células secretoras de toxinas. A catepsina pode auxiliar no mecanismo de reparação do espinho, quando quebrado.Echinometra lucunter, the sea urchin responsible for 50% of marine animals accidents, cause inflammation and pain by the spine penetration, effects attributed to the mechanical trauma. Accidents were reported after the ingestion of raw. The celomic fluid and spines were fractionated and purified, procedure repeated until pure molecules were obtained, tested for inflammation models. Histological analyses and enzymatic assays were performed. A molecule from spines and a peptide from the celomic fluid caused inflammatory effects. Moreover, a cathepsin B/X activity could be identified in the spines. An organized histological structure in the spine was observed, with cells embedded in a calcified matrix, as well as granulous cells displaying proteic contents, typical of secretory cells. It was possible to conclude that the spine and the celomic fluid of E. lucunter do contain inflammatory toxins that prolong the spine puncturing event itself, and the spine possesses a toxin secretory structure. The cathepsin would be present in a mechanism of tissue remodeling

Characterization of the Bothrops jararaca snake venom effects on rat vas deferens

BV UNIFESP: Teses e dissertaçõe