Manuela Berto Pucca

Amphibian poisons are one of the most complex chemical defense systems among vertebrates, yet their diversity remains largely unresolved. Here, we present a comparative peptidomic analysis of six Amazonian species of Monkey Tree Frogs (Phyllomedusidae) sampled across three geographic regions. Mass spectrometry-based profiling revealed 18,466 features. Despite this extensive diversity, a subset of 961 features was shared across all species, while thousands of additional features were restricted to individual taxa or combinations of taxa. Poison profiles showed a highly uneven relative abundance distribution, with a small number of peptides accounting for a large proportion of the detected signal. Phylloseptins and dermaseptins were prominent components of several profiles, whereas bradykinin-related peptides, tryptophyllins, dermorphin-like peptides, medusins, and phyllomedusins showed variable contributions across taxa and regions. Geographic variation in the relative abundance of major peptide subfamilies indicates differences in peptide composition among the sampled populations. Such patterns are consistent with spatially structured variation and align with previous studies suggesting that amphibian peptide repertoires may be shaped by local ecological and biotic interactions. Our results reveal substantial variation in peptide composition and relative abundance while maintaining a broadly shared molecular component across phyllomedusid taxa. This study expands current knowledge of amphibian chemical diversity and provides new insights into how ecological and evolutionary processes may contribute to the diversification of chemical defense systems.

Bothrops marajoensis is a Brazilian pit viper whose venom remains poorly characterized compared with those of other medically important Bothrops species. In the present study, we performed a comparative biochemical characterization of B. marajoensis venom with six additional Bothrops venoms (B. alternatus, B. atrox, B. jararaca, B. jararacussu, B. moojeni, and B. neuwiedi). Venoms were analyzed by reversed-phase chromatography, electrophoresis, immunorecognition by commercial bothropic antivenom, phosphodiesterase activity, and their effects on the viability of differentiated C2C12 myotubes. Chromatographic and electrophoretic analyses revealed a largely conserved overall venom composition among species, with qualitative differences, although quantitative differences in protein relative abundance were evident. Bothropic antivenom recognized all venoms, indicating broad antigenic cross-reactivity despite venom variation. B. marajoensis exhibited intermediate phosphodiesterase (PDE) activity relative to other species evaluated, confirming functional variability among Bothrops venoms. In the cell viability assay, B. marajoensis displayed comparatively low apparent cytotoxicity toward differentiated C2C12 myotubes, maintaining higher cell viability than highly myotoxic venoms such as those of B. jararacussu and B. moojeni. These findings expand the biochemical characterization of B. marajoensis venom and demonstrate that, although venoms share the conserved toxin repertoire typical for Bothrops genus, quantitative differences influence its biological activities, preserving broad recognition by bothropic antivenom.

Leishmaniasis and Chagas disease are neglected tropical diseases that continue to pose significant public health challenges, highlighting the need for new therapeutic strategies. Brazilian snake venoms represent a valuable and underexplored source of bioactive molecules with diverse pharmacological activities and promising therapeutic potential. In this context, the present study aimed to investigate the in vitro antiprotozoal potential of venoms from Bothrops and Crotalus species, including Bothrops jararacussu, Bothrops pauloensis, Bothrops alternatus, Bothrops leucurus, Bothrops atrox, Bothrops jararaca, Crotalus durissus terrificus, and Crotalus durissus ruruima, metalloprotease (MTL)- and crotoxin (CTX)-enriched, against Leishmania spp. and Trypanosoma cruzi. Crude venom protein profiles were analyzed by SDS-PAGE, and cytotoxicity was assessed in differentiated C2C12 myotubes and murine peritoneal macrophages. Antiprotozoal activity was evaluated against extracellular parasite forms, including promastigotes of Leishmania amazonensis and Leishmania infantum and epimastigotes of T. cruzi. Venoms exhibiting the highest selectivity indices (SIs), calculated using murine macrophage cytotoxicity data, were further tested against intracellular amastigotes of L. amazonensis. Among the tested samples, B. jararacussu venom showed activity against promastigotes of both L. amazonensis (IC₅₀ = 2.9 µg mL⁻¹) and L. infantum (IC₅₀ = 2.8 µg mL⁻¹), as well as in epimastigotes of T. cruzi (IC₅₀ = 15.5 µg mL⁻¹). The MTLand CTX pools from C. d. ruruima venom exhibited the highest activity against promastigotes of L. amazonensis, with IC₅₀ values of 1.6 and 3.8 µg mL⁻¹, respectively. Against intracellular amastigotes, MTL and CTX showed IC₅₀ values of 4.1 and 2.5 µg mL⁻¹, respectively, with selectivity indices (SIs) of 73.1 and 120, respectively. Overall, these findings provide preliminary evidence for the antiparasitic potential of snake venom-derived molecules, supporting further characterization and in vivo evaluation.

Crotamine is a low-molecular-weight cationic polypeptide isolated from Crotalus durissus terrificus snake venom, classified as a non-enzymatic toxin with distinctive structural and functional properties. This toxin also exhibits characteristics of a cell-penetrating peptide, owing to its ability to translocate across biological membranes in a largely non-specific manner and to deliver diverse molecular cargos into cells. Beyond its well-established internalization capacity, emerging evidence suggests that crotamine exerts immunomodulatory effects. In our mini review, we discuss current advances in understanding crotamine as a venom-derived immunomodulatory peptide, highlighting its structural similarities with host defense peptides, its interactions with immune cells, and its potential applications in immunotherapy and drug delivery.

Amid an ongoing environmental crisis marked by high deforestation rates in the Brazilian Amazon, two new species of chactid scorpions are herein described. Cayooca puchus sp. n. is described from an inselberg in the municipality of Mucajaí, state of Roraima, northern Brazilian Amazon. The new species resembles Cayooca venezuelensis but differs by denser body granulation and strongly costate, scattered granular ventromedian and ventral prosubmedian carinae. Brotheas cernii sp. n., described from the same locality, resembles Brotheas granulatus and B. subgranulatus but differs by smaller body size, granular ventral carinae on metasomal segment I, strongly granular pedipalp chelae, and spinoid granules on ventral metasomal carinae of segments III–V. These findings reinforce the Amazon as a major center of biodiversity and highlight the likelihood that numerous species remain undescribed.

Venoms from Bothrops species and Daboia russelii are among the leading causes of venom‐induced coagulopathy and snakebite‐related deaths. In this study, we comparatively evaluated the biochemical composition and hemostatic effects of venoms from seven Bothrops species and D. russelii using protein profiling and functional coagulation assays. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) analysis revealed broadly similar molecular weight distributions between the two genera, consistent with the presence of snake venom metalloproteinases, serine proteases, and phospholipases A ₂ , but with notable interspecific variability among Bothrops venoms. Enzymatic assays demonstrated heterogeneous metalloproteinase, serine protease, and phospholipase A ₂ activities across Bothrops species, whereas D. russelii venom showed strong phospholipase A ₂ activity and limited fibrinogenolytic activity. Functional coagulation analyses revealed marked differences between the genera. Bothrops venoms induced rapid clot initiation, with alterations in clot formation observed in a species‐dependent manner, accompanied by pronounced fibrinogen degradation, consistent with consumption coagulopathy driven by fibrinogenolysis and clot destabilization. In contrast, D. russelii venom exhibited a strong procoagulant profile, significantly reducing prothrombin time and activated partial thromboplastin time, with minimal direct fibrinogen degradation. Previous studies have shown that D. russelii venom also promotes rapid clot formation in rotational thromboelastometry assays. Together, these findings demonstrate that Bothrops spp. and D. russelii venoms converge functionally in disrupting hemostasis but do so through distinct biochemical strategies, providing experimental support for the divergent coagulation phenotypes observed clinically.

Toxic exposures remain a major global health concern, particularly in tropical regions where environmental and 12 occupational challenges intensify their impact. This editorial highlights a broad spectrum of toxic agents, including heavy 13 metals, industrial chemicals, pesticides, air pollutants, food additives, household and water contaminants, biological toxins, 14 pharmaceuticals, radiation, and emerging nanomaterials. The eight studies featured in this collection jointlly advance our 15 understanding of the complex mechanisms underlying toxic injuries and illnesses, while emphasizing the need for improved 16 preventive strategies, diagnostic approaches, and therapeutic interventions to mitigate their health and environmental 17 consequences.Investigating toxic exposures is a relevant subject specially on how these compounds play their roles in cells and which 280 were fatal, corresponding to a case-fatality rate of 11.82%. The fatality rate was higher among males (13.35%) than 49 females (10.03%) and increased with age. Regarding pesticide classes, insecticides accounted for 66.05% of poisoning cases,