Search Results (702)

Australian elapid snakes possess potent procoagulant venoms, capable of inducing severe venom-induced consumption coagulopathy (VICC) in snakebite victims through rapid activation of the coagulation cascade by converting the FVII and prothrombin zymogens into their active forms. These venoms fall into two mechanistic categories: FXa-only venoms, which hijack host factor Va, and FXa:FVa venoms, containing a complete venom-derived prothrombinase complex. While previous studies have largely focused on human plasma, the ecological and evolutionary drivers behind prey-selective venom efficacy remain understudied. Here, thromboelastography was employed to comparatively evaluate venom coagulotoxicity across prey classes (amphibian, avian, rodent) and human plasma, using a taxonomically diverse selection of Australian snakes. The amphibian-specialist species Pseudechis porphyriacus (Red-Bellied Black Snake) exhibited significantly slower effects on rodent plasma, suggesting evolutionary refinement towards ectothermic prey. In contrast, venoms from dietary generalists retained broad efficacy across all prey types. Intriguingly, notable divergence was observed within Pseudonaja textilis (Eastern Brown Snake): Queensland populations of this species, and all other Pseudonaja (brown snake) species, formed rapid but weak clots in prey and human plasma. However, the South Australian populations of P. textilis produced strong, stable clots across prey plasmas and in human plasma. This is a trait shared with Oxyuranus species (taipans) and therefore represents an evolutionary reversion towards the prothrombinase phenotype present in the Oxyuranus and Pseudonaja last common ancestor. Clinically, this distinction has implications for the pathophysiology of human envenomation, potentially influencing clinical progression, including variations in clinical coagulopathy tests, and antivenom effectiveness. Thus, this study provides critical insight into the ecological selection pressures shaping venom function, highlights intraspecific venom variation linked to geographic and phylogenetic divergence, and underscores the importance of prey-focused research for both evolutionary toxinology and improved clinical management of snakebite. Full article

Acanthophis antarcticus, commonly known as the death adder, is a venomous Australian snake and a member of the Elapidae family. Due to its robust body and triangular head, it was historically misclassified as a viper. Its venom is known for neurotoxic, hemorrhagic, and hemolytic effects but displays low anticoagulant activity. Although key toxins such as three-finger toxins (3FTxs) and phospholipase A₂ (PLA₂) have been previously described, no study has integrated proteomic and functional analyses to date. In this study, we conducted a comprehensive characterization of A. antarcticus venom. Reverse-phase high-performance liquid chromatography (RP-HPLC) followed by LC-MS/MS enabled the identification of nine toxin families, with 3FTxs and PLA₂ as the most abundant. Less abundant but functionally relevant toxins included Kunitz-type inhibitors, CRISP, SVMP, LAAO, NGF, natriuretic peptides, and nucleotidases, the latter being reported here for the first time based on proteomic evidence. Hydrophilic interaction chromatography (HILIC) coupled with MALDI-TOF was used to analyze polar, non-retained venom components, revealing the presence of low-molecular-weight peptides (2–4 kDa). Functional assays confirmed the enzymatic activity of HYAL, PLA₂, and LAAO and, for the first time, demonstrated inhibitory activity on serine peptidases and fibrinogenolytic activity in the venom of this species. These findings expand our understanding of the biochemical and functional diversity of this venom. Full article

Differences in venom within snake species can affect the efficacy of antivenom, but how this variation manifests across broad geographical scales remains poorly understood. Naja atra envenoming causes severe morbidity in China, yet whether intraspecific venom variation exists across mainland regions is unknown. We collected venom samples from seven biogeographical regions (spanning > 2000 km latitude). Venom lethality, systemic toxicity (organ damage biomarkers and coagulopathy), and histopathology of major organs were assessed. Neutralization by antivenom and label-free quantitative proteomics (LC-MS/MS) were also performed. The results revealed a non-uniform LD₅₀, with venom from Yunnan exhibiting the highest lethality (2.1-fold higher than venom from Zhejiang, p < 0.001). Commercial antivenom showed lower neutralization efficacy against the venom from the Yunnan, Guangxi, and Guangdong regions. Regarding organ damage and coagulopathy, venom from Yunnan caused severe liver damage, while venom from the Zhejiang region induced significant coagulopathy. Finally, proteomic profiles identified 175 proteins: venom from Yunnan was dominated by phospholipases, contrasting with eastern regions (Anhui/Zhejiang: cytotoxins CTXs > 30%). Venom from Guangdong contained higher levels of the weak neurotoxin NNAM2 (5.2%). Collectively, significant geographical divergence exists in Chinese Cobra venom composition, systemic toxicity, and antivenom susceptibility, driven by differential expression of key toxins. Our study provides a molecular basis for precision management of snakebites, and we call for optimized antivenom production tailored to regional variations. Full article

Venoms of the Palearctic vipers in the Macrovipera genus cause severe procoagulant clinical effects, yet the precise molecular targets remain incompletely defined. To fill this toxicological knowledge gap, we tested five Macrovipera venoms—M. lebetina cernovi, M. l. obtusa, M. l. turanica (Turkmenistan and Uzbekistan localities), and M. schweizeri—using plasma clotting assays, Factors VII, X, XI, and XII and prothrombin zymogen activation assays, and SDS-PAGE to visualise Factor V (FV) cleavage. All venoms induced extremely rapid clot formation (10.5–12.5 s) compared with the negative control (spontaneous clotting) of 334.6 ± 3.6 s) and the positive control (kaolin trigger) of 55.8 ± 1.9 s. Activation of FVII or FXI was negligible, whereas consistent FX activation and species-variable FXII activation, both moderate, were observed. Prothrombin remained inert in the absence of cofactors, but the presence of FV or FVa elicited potent thrombin generation. SDS-PAGE confirmed proteolytic conversion of the 330 kDa FV zymogen into the ~105 kDa heavy and ~80 kDa light chains of FVa by the venoms of all species. This data demonstrates that Macrovipera venoms rely on a dual enzyme strategy: (i) activation of FV to FVa by serine proteases and (ii) FVa-dependent prothrombin activation by metalloproteases. These results reveal that prothrombin activation is the dominant procoagulant pathway and overshadows the historically emphasised FX activation. This mechanism mirrors, yet is evolutionarily independent from, the FXa:FVa prothrombinase formation seen in Australian elapid venoms, highlighting convergent evolution of cofactor-hijacking strategies among snakes. The discovery of potent FVa-mediated prothrombin activation in Macrovipera challenges existing paradigms of viperid venom action, prompts re-evaluation of related genera (e.g., Daboia), and underpins the design of targeted antivenom and therapeutic interventions. Full article

Many vertebrates have evolved resistance to snake venom as a result of coevolutionary chemical arms races. In Australian skinks (family Scincidae), who often encounter venomous elapid snakes, the frequency, diversity, and molecular basis of venom resistance have been unexplored. This study investigated the evolution of neurotoxin resistance in Australian skinks, focusing on mutations in the muscle nicotinic acetylcholine receptor (nAChR) α1 subunit’s orthosteric site that prevent pathophysiological binding by α-neurotoxins. We sampled a broad taxonomic range of Australian skinks and sequenced the nAChR α1 subunit gene. Key resistance-conferring mutations at the toxin-binding site (N-glycosylation motifs, proline substitutions, arginine insertions, changes in the electrochemical state of the receptor, and novel cysteines) were identified and mapped onto the skink organismal phylogeny. Comparisons with other venom-resistant taxa (amphibians, mammals, and reptiles) were performed, and structural modelling and binding assays were used to evaluate the impact of these mutations. Multiple independent origins of α-neurotoxin resistance were found across diverse skink lineages. Thirteen lineages evolved at least one resistance motif and twelve additional motifs evolved within these lineages, for a total of twenty-five times of α-neurotoxic venoms resistance. These changes sterically or electrostatically inhibit neurotoxin binding. Convergent mutations at the orthosteric site include the introduction of N-linked glycosylation sites previously known from animals as diverse as cobras and mongooses. However, an arginine (R) substitution at position 187 was also shown to have evolved on multiple occasions in Australian skinks, a modification previously shown to be responsible for the Honey Badger’s iconic resistance to cobra venom. Functional testing confirmed this mode of resistance in skinks. Our findings reveal that venom resistance has evolved extensively and convergently in Australian skinks through repeated molecular adaptations of the nAChR in response to the enormous selection pressure exerted by elapid snakes subsequent to their arrival and continent-wide dispersal in Australia. These toxicological findings highlight a remarkable example of convergent evolution across vertebrates and provide insight into the adaptive significance of toxin resistance in snake–lizard ecological interactions. Full article

Background/Objectives: Most snakebite incidents in Latin America are caused by species of the Bothrops genus. Their venom induces severe local effects, against which antivenom therapy has limited efficacy. Metabolites derived from Coffea arabica have demonstrated anti-inflammatory and anticoagulant properties, suggesting their potential as therapeutic agents to inhibit the local effects induced by B. asper venom. Methods: Three enzymatic assays were performed: inhibition of the procoagulant and amidolytic activities of snake venom serine proteinases (SVSPs); inhibition of the proteolytic activity of snake venom metalloproteinases (SVMPs); and inhibition of the catalytic activity of snake venom phospholipases A₂ (PLA_2s). Additionally, molecular docking studies were conducted to propose potential inhibitory mechanisms of the metabolites chlorogenic acid, caffeine, and caffeic acid. Results: Green and roasted coffee extracts partially inhibited the enzymatic activity of SVSPs and SVMPs. Notably, the green coffee extract, at a 1:20 ratio, effectively inhibited PLA₂ activity. Among the individual metabolites tested, partial inhibition of SVSP and PLA₂ activities was observed, whereas no significant inhibition of SVMP proteolytic activity was detected. Chlorogenic acid was the most effective metabolite, significantly prolonging plasma coagulation time and achieving up to 82% inhibition at a concentration of 62.5 μM. Molecular docking analysis revealed interactions between chlorogenic acid and key active site residues of SVSP and PLA₂ enzymes from B. asper venom. Conclusions: The roasted coffee extract demonstrated the highest inhibitory effect on venom toxins, potentially due to the formation of bioactive compounds during the Maillard reaction. Molecular modeling suggests that the tested inhibitors may bind to and occupy the substrate-binding clefts of the target enzymes. These findings support further in vivo research to explore the use of plant-derived polyphenols as adjuvant therapies in the treatment of snakebite envenoming. Full article

Plant latex is a rich source of proteolytic enzymes with potential biomedical applications, particularly in hemostasis. Among them, thrombin-like enzymes (TLEs) have garnered interest in their ability to mimic thrombin by catalyzing the conversion of fibrinogen to fibrin, facilitating clot formation. While TLEs from snake venoms have been well-characterized and applied clinically, their plant-derived counterparts remain underexplored. This review critically examines the structural and functional characteristics of TLEs from plant latex, comparing them to animal-derived TLEs and evaluating their role in both procoagulant and fibrinolytic processes. Emphasis is placed on dual fibrinogenolytic and fibrinolytic activities exhibited by latex proteases, which often vary with concentration, incubation time, and protease type. In vitro coagulation assays and electrophoretic analyses are discussed as critical tools for characterizing their multifunctionality. By addressing the knowledge gaps and proposing future directions, this paper positions plant latex proteases as promising candidates for development in localized hemostatic and thrombolytic therapies. Full article

Three-finger toxins (3FTxs) are the largest group of nonenzymatic toxins found in snake venoms. Among them, neurotoxins that target nicotinic acetylcholine receptors are the most well-studied ligands. In addition to the classical neurotoxins, several other new classes have been characterized for their structure, receptor subtype, and species selectivity. Here, we systematically analyzed over 700 amino acid sequences of three-finger neurotoxins that interact with nicotinic acetylcholine receptors. Based on the amino acid residue substitutions in the functional sites and structural features of various classes of neurotoxins, we have classified them into over 150 distinct subgroups. Currently, only a small number of typical examples representing these subgroups have been studied for their structure, function, and subtype selectivity. The functional site residues responsible for their interaction with specific receptor subtypes of several toxins are yet to be identified. The molecular details of each subgroup representative toxin with its target receptor will contribute towards the understanding of subtype- and/or interface-selectivity. Thus, this review will provide new impetus in the toxin research and pave the way for the design of potent, selective ligands for nicotinic acetylcholine receptors. Full article

The snakes from the genus Bothrops are responsible for most of the ophidic accidents in Brazil, and Bothrops atrox represents one of these species. Envenomation by these snakes results in systemic effects and is often associated with early mortality following snakebite incidents. The present study investigates the pharmacological properties of Bothrops atrox venom (VBA), focusing specifically on its impact on renal blood flow. Following the renal perfusion procedure, kidney tissues were processed for histopathological examination. Statistical analysis of all evaluated parameters was conducted using ANOVA and Student’s t-test, with significance set at p < 0.005. Administration of VBA resulted in a marked reduction in both perfusion pressure and renal vascular resistance. In contrast, there was a significant elevation in urinary output and glomerular filtration rate. Histological changes observed in the perfused kidneys were mild. The involvement of nitric oxide in the pressor effects of Bothrops atrox venom was not investigated in renal perfusion systems or in in vivo models. Treatment with VBA led to elevated nitrite levels in the bloodstream of the experimental animals. This effect was completely inhibited following pharmacological blockade with L-NAME. Based on these findings, we conclude that VBA alters renal function and promotes increased nitric oxide production. Full article

This study investigated the effects of Bothrops moojeni (B. moojeni) venom and its high- (HMM) and low-molecular mass (LMM) fractions on human osteoclast (OC) differentiation and function in vitro, aiming to identify novel therapeutics for bone disorders. Venom preparations were applied at 5 µg/mL (crude venom and HMM) or 1 µg/mL (LMM) from day 4 of peripheral blood mononuclear cell (PBMC) differentiation through terminal OC formation, enabling evaluation across early differentiation, fusion, and maturation stages. RNA sequencing revealed 7793 genes common to all experimental groups, with unique gene expression signatures of 149 (control), 221 (HMM), 248 (crude venom), and 60 (LMM) genes, reflecting distinct molecular responses. The negative control PBMC group exhibited 1013 unique genes enriched in immune-related pathways, consistent with their undifferentiated state. Crude venom induced the broadest transcriptional modulation, upregulating key fusion (CD47) and resorption (CTSK) genes, and altering markers of OC differentiation. The HMM fraction predominantly influenced inflammatory and osteoclastogenic pathways, notably TNF and NF-κB signaling, while the LMM fraction selectively regulated fusion-related genes (e.g., CD44) and immune pathways, indicating targeted modulation of OC activity. Cytokine profiling showed that crude venom and HMM suppressed osteoclastogenic cytokines such as IL-1β and IL-6, supporting their potential use in inflammatory bone diseases. Pathway enrichment analyses confirmed these differential effects on immune response and bone resorption mechanisms. Together, these results demonstrate that B. moojeni venom and its fractions differentially impact OC biology, with crude venom exerting broad effects and HMM and LMM fractions offering more specific modulation. Future studies will isolate bioactive components and assess therapeutic efficacy in animal models of osteoporosis and rheumatoid arthritis. Full article

Snakebite remains the most neglected tropical disease globally, with India experiencing the highest rates of mortality and morbidity. While most envenomation cases in India are attributed to the ‘big four’ snakes, research has predominantly focused on Russell’s viper (Daboia russelii), spectacled cobra (Naja naja), and common krait (Bungarus caeruleus), leading to a considerable gap in our understanding of saw-scaled viper (Echis carinatus carinatus) venoms. For instance, the venom gland transcriptome and inter- and intra-population venom variation in E. c. carinatus have largely remained uninvestigated. A single study to date has assessed the effectiveness of commercial antivenoms against this species under in vivo conditions. To address these crucial knowledge gaps, we conducted a detailed investigation of E. c. carinatus venom and reported the first venom gland transcriptome. A proteotranscriptomic evaluation revealed snake venom metalloproteinases, C-type lectins, L-amino acid oxidases, phospholipase A₂s, and snake venom serine proteases as the major toxins. Moreover, we assessed the intra-population venom variation in this species using an array of biochemical analyses. Finally, we determined the venom toxicity and the neutralising efficacy of a commercial antivenom using a murine model of snake envenoming. Our results provide a thorough molecular and functional profile of E. c. carinatus venom. Full article

Leukemias and lymphomas are hematologic malignancies characterized by complex pathophysiological mechanisms and increasing global incidence. Despite advances in chemotherapy, immunotherapy, and targeted therapies, challenges such as drug resistance and relapse persist, necessitating novel therapeutic strategies. This review explores the cytotoxic potential of venoms derived from snakes, bees, and scorpions against leukemia and lymphoma cells. Numerous venom-derived components, such as L-amino acid oxidases (LAAOs), phospholipases A₂ (PLA₂s), and peptides like melittin, demonstrate selective antitumor activity through mechanisms involving oxidative stress, apoptosis induction, cell cycle arrest, and immunomodulation. These molecules exert their effects via mitochondrial pathways, caspase activation, and inhibition of pro-survival signaling cascades such as NF-κB and PI3K/Akt. Despite promising preclinical results, the clinical translation of these bioactive compounds remains limited due to challenges in standardization, delivery, and safety profiling. This review highlights recent advances in venom research, summarizes key molecular targets, and discusses future directions to harness venom-derived molecules as innovative therapies for hematological cancers. Full article

The composition of Australian snake venoms is the least well-known of any continent. We characterised the venom proteome of the southern death adder Acanthophis antarcticus—one of the world’s most morphologically and ecologically divergent elapids. Using a combined bottom-up proteomic and venom gland transcriptomic approach employing reverse-phase chromatographic and gel electrophoretic fractionation strategies in the bottom-up proteomic workflow, we characterised 92.8% of the venom, comprising twelve different toxin identification hits belonging to seven toxin families. The most abundant protein family was three-finger toxins (3FTxs; 59.8% whole venom), consisting mostly of one long-chain neurotoxin, alpha-elapitoxin-Aa2b making up 59% of the venom and two proteoforms of another long-chain neurotoxin. Phospholipase A₂s (PLA₂s) were the second most abundant, with four different toxins making up 22.5% of the venom. One toxin was similar to two previous non-neurotoxic PLA₂s, making up 16% of the venom. The remaining protein families present were CTL (3.6%), NGF (2.5%), CRiSP (1.8%), LAAO (1.4%), and AChE (0.8%). A. antarcticus is the first Australian elapid characterised that has a 3FTx dominant venom, a composition typical of elapids on other continents, particularly cobras Naja sp. The fact that A. antarcticus has a venom composition similar to cobra venom while having a viper-like ecology illustrates that similar venom expressions can evolve independently of ecology. The predominance of post-synaptic neurotoxins (3FTxs) and pre-synaptic neurotoxins (PLA₂) is consistent with the neurotoxic clinical effects of envenomation in humans. Full article

Background: Ophidism is a globally neglected health problem. In Argentina, Crotalus durissus terrificus (C.d.t., South American rattlesnake) is one of the species of greatest medical importance since its venom contains mainly crotoxin (CTX), a potent enzyme–toxin with PLA₂ activity, which is responsible for its high lethality. Objective: In this work, we aimed to generate nanovenoms (NVs), complexes formed by CTX adsorbed onto 150 nm silica nanoparticles (SiNPs), and to study their physicochemical, biological, and immunomodulatory activities for potential use as adjuvants (ADJs) in antivenom (AV) production. Methods: CTX was isolated and corroborated by SDS-PAGE. Then, CTX was adsorbed on the synthetized Stöber SiNPs’ surfaces, forming a monolayer and retaining its biological activity (as observed by the MTT cell proliferation assay using the THP-1 cell line). Results: Immunomodulatory activity revealed a high pro-inflammatory (IL-1β) response induced by SiNPs followed by NVs. In the case of the anti-inflammatory response, NVs presented significant differences for TGF-β only after cell activation with LPS. No significant differences were observed in IL-10 levels. Conclusions: Thus, these results suggest that NVs together with SiNPs could increase immunogenicity and enhance immune response, turning them into potential tools for the generation of new antivenoms. Full article

Background: Snake envenomation is a major public health issue in Nigeria, primarily due to bites from Echis ocellatus, Naja nigricollis, and Bitis arietans. Understanding their venom composition is essential for effective antivenom development. This study characterizes and compares the venom proteomes of these snakes using iTRAQ-based proteomics, focusing on key toxin families and their relative abundances. Methods: Venom samples were ethically collected from adult snakes, pooled by species, lyophilized, and stored for proteomic analysis. Proteins were extracted, digested with trypsin, and labeled with iTRAQ. Peptides were analyzed via mass spectrometry, and data were processed using Mascot and IQuant for protein identification and quantification. Results: E. ocellatus and B. arietans venoms had similar profiles, rich in C-type lectins, serine proteases, and phospholipase A₂s. These comprised 17%, 11%, and 5% in E. ocellatus and 47%, 10%, and 7% in B. arietans, with metalloproteinases dominating both (53% and 47%). In N. nigricollis, three-finger toxins (9%) were most abundant, followed by metalloproteinases (3%). All species shared four core protein families, with N. nigricollis also containing four uncharacterized proteins. Conclusions: This study highlights venom compositional differences, advancing snake venom biology and informing targeted antivenom development. Full article