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In Brazil, where puffer fish are considered poisonous, there are few documented cases on human consumption and consequent poisoning. In this study, toxicity of two puffer fish species from the Brazilian coast was examined. Specimens of Sphoeroides spengleri and Lagocephalus laevigatus were caught in São Sebastião Channel (North coast of São Paulo State, Brazil) between January 1996 and May 1997. Acidic ethanol extracts from muscle and skin plus viscera were tested for mice acute toxicity using the standard method of Kawabata. Polar extracts of S. spengleri showed high toxicity up to 946 MU/g. Extracts from L. laevigatus showed very low levels of toxicity, never exceeding 1.7 MU/g. All extracts from both species blocked amielinic nerve fiber evoked impulses of crustacean legs; this effect reverted on washing similar to the standard tetrodotoxin TTX. The aqueous extract solutions were partially purified using an ionic exchange column (Amberlit GC-50) followed by treatment with activated charcoal (Norit-A). The presence of TTX and their analogs in the semi-purified extracts were confirmed by HPLC and mass spectrometry (MALDI-TOF)

The mouse, chicken, African clawed frog, and zebrafish are considered ¨model organisms¨ due to their extensive embryological and genetic characterization. However, they are far from representative of known diversity, impairing phylogenetic analyses of developmental patterns. Since squamates have historically received limited attention in developmental studies, we here describe the developmental sequence for Tropidurus torquatus, and provide the first post-ovipositional developmental series for the lizard family Tropiduridae. Fifteen developmental stages are described based on morphological traits such as the eye and accessory visual structures, pharyngeal arches, fusion of facial primordia, limb development, pigmentation, and scales. Organogenesis is already in progression at oviposition (Stage 28), with embryos continuing to develop at the incubation temperature of 30°C ± 1°C, and hatching after 75 ± 5 days, at Stage 42. Comparisons with other lizards show a conserved embryonic sequence, however developmental timing differences were found in features such as the pharyngeal arches, endolymphatic sacs, pigmentation and scales. The development of the phallic and cranial lip of the cloaca anlages are compared with that of other lizards. The order of T. torquatus fore- and hindlimb formation differs from that most commonly observed in lizards. The abundance and close association of this species with urban environments, as well as the ease of capturing and managing females, makes T. torquatus an attractive source of developmental data for future experimental and ontogenetic studies. Anat Rec, 300:277-290, 2017. © 2016 Wiley Periodicals, Inc.

Nowadays, the emergence of resistance to the current available chemotherapeutic drugs by cancer cells makes the development of new agents imperative. The skin secretion of amphibians is a natural rich source of antimicrobial peptides (AMP), and researchers have shown that some of these wide spectrum molecules are also toxic to cancer cells. The aim of this study was to verify a putative anticancer activity of the AMP pentadactylin isolated for the first time from the skin secretion of the frog Leptodactylus labyrinthicus and also to study its cytotoxic mechanism to the murine melanoma cell line B16F10. The results have shown that pentadactylin reduces the cell viability of B16F10 cells in a dose-dependent manner. It was also cytotoxic to normal human fibroblast cells; nevertheless, pentadactylin was more potent in the first case. The studies of action mechanism revealed that pentadactylin causes cell morphology alterations (e.g., round shape and shrinkage morphology), membrane disruption, DNA fragmentation, cell cycle arrest at the S phase, and alteration of mitochondrial membrane potential, suggesting that B16F10 cells die by apoptosis. The exact mechanism that causes reduction of cell viability and cytotoxicity after treatment with pentadactylin is still unknown. In conclusion, as cancer cells become resilient to death, it is worthwhile the discovery of new drugs such as pentadactylin that induces apoptosis.

Toxicity and toxin identification in Colomesus asellus, an Amazonian (Brazil) freshwater puffer fish. By using four different techniques--mouse bioassay, ELISA, HPLC and mass spectrometry-we evaluated the toxicity in the extracts of C. asellus, a freshwater puffer fish from the rivers of the Amazon, and identified for the first time the components responsible for its toxicity. The T20G10 monoclonal antibody raised against TTX, and employed in an indirect competitive enzyme immunoassay, showed very low affinity for the C. asellus extracts, indicating that TTX and its analogs are not the main toxic components of the extracts. This antibody was efficient in detecting presence of TTX in a total extract of Sphoeroides spengleri, which is one of the most toxic puffer fish found in the Atlantic coast. Extracts of C. asellus were toxic when administered intraperitonially into mice with an average toxicity of 38.6+/-12 mouse unit (MU)/g, while HPLC analysis indicated a lower toxin content (7.6+/-0 5MU/g). The HPLC profile showed no traces of TTX, but only the presence of PSPs (STX, GTX 2 and GTX 3). These toxins were also confirmed by electrospray ionization mass spectrometry.

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