Venom Toxicity Research Articles

Exploring the Venom Gland Transcriptome of Bothrops asper and Bothrops jararaca: De Novo Assembly and Analysis of Novel Toxic Proteins

Previous proteomic studies of viperid venom revealed that it is mainly composed of metalloproteinases (SVMPs), serine proteinases (SVSPs), phospholipase A2 (PLA2), and C-type lectins (CTLs). However, other proteins appear in minor amounts that affect prey and need to be identified. This study aimed to identify novel toxic proteins in the venom gland transcriptome of Bothrops asper and Bothrops jararaca, using data from NCBI. Bioinformatics tools were used to assemble, identify, and compare potentially novel proteins in both species, and we performed functional annotation with BLASTX against the NR database. While previous assemblies have been performed for B. jararaca, this is the first assembly of the B. asper venom gland transcriptome. Proteins with potentially novel functions were identified, including arylsulfatase and dihydroorotate dehydrogenase, among others, that could have implications for venom toxicity. These results suggest that the identified proteins may contribute to venom toxic variation and provide new opportunities for antivenom research. The study improves the understanding of the protein composition of Bothrops venom and suggests new possibilities for the development of treatments and antivenoms.

The neurotoxic effect of Naja nubiae (Serpentes: Elapidae) venom from Sudan.

Neurotoxicity is a common feature of elapid snake envenomation. There are limited studies on the toxicity of Naja nubiae venom, the Nubian spitting cobra, from north-east Africa. We used the chick biventer cervicis nerve-muscle preparation to demonstrate the neurotoxic effect of N. nubiae venom and to compare it with the potent neurotoxic cobra Naja melanoleuca venom. Venoms were separated by successive reverse-phase high-performance liquid chromatography (RP-HPLC) runs and the molecular mass of the neurotoxins was determined by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Both venoms caused time-dependent inhibition of nerve-mediated twitches with a t90 value of 22.2±1.9min and 12.9±1.2min for N. nubiae and N. melanoleuca venoms, respectively. Prior incubation of some commercial antivenom (EchiTab-Plus-ICP [Costa Rica], CSL, Parkville, Victoria, Australia) and snake venom antisera [India]) did not prevent the neurotoxic effect of N. nubiae venom. The chromatographic separation of N. nubiae and N. melanoleuca venoms followed by MALDI-TOF MS analysis revealed that short-chain α-neurotoxin accounted for 8.4% of N. nubiae and 14.8% of N. melanoleuca whole venoms. N. nubiae venom, which was previously known as cytotoxic venom, exhibits considerable in vitro neurotoxic effects on chick nerve-muscle preparations that may have consequences for antivenom development in north-east Africa.

Extraordinary variance in meta-analysis of venom toxicity of 160 most lethal ophidians and guidelines for estimating human lethal dose range.

This is the first meta-analysis to characterize intra-ophidian-species variation in whole venom. Being the largest possible meta-analysis at this time, it encompasses all known records of animal lethality studies over the past 100 years. These results were not artifacts of resistant test-animal species and showed orders of magnitude beyond the 1.6 logs (40-fold change) range of lethal dose documented in the literature between amphibians, lizards, and mice. A total of 1003 lethal dose study results for 160 of the most lethal venomous ophidian species in the world were analyzed. LDLo was not different from LD50 across studies, indicating the true range of toxicity is probably larger. The belief that, for the route of inoculation, IC < IV < IP < IM < SC was well supported (R2 = 0.90). However, 5% of ICs were the highest dose, and 7% of SC inoculations were the lowest dose. Within the mouse test species, for one route of inoculation, the widest LD range was 2.96 logs (917-fold change, N = 20). Within mouse species, for multiple routes of inoculation, the widest LD range was 3.6 logs (4,150-fold change, N = 20). The strongest correlation for the range of lethal dose results was the number of studies (R2 = 0.56), followed by the number of test-animal species (R2 = 0.55) and then the number of routes of inoculation (R2 = 0.43). Scientists working with humans should use combined LDLo and LD50 meta-datasets for all data and calculate mean, median, minimum, range, and standard deviation as shown in the supplement spreadsheet, and the equations we provide. Standard deviation multiples may provide the desired safety for experimenters. For estimating the LD50 range and minimum lethal dose for species with little data, we recommend curating a meta-dataset of related snakes, and computational research to strengthen this estimation.

Nematocyst Types and Characteristics in the Tentacles of Gershwinia thailandensis and Morbakka sp. (Cubozoa: Carybdeida) from the Gulf of Thailand.

Nematocysts, specialized stinging cells in cnidarians, play a crucial role in both defense and prey capture, containing venomous, coiled tubes within a capsule. While box jellyfish are recognized as a medical threat, information on the nematocysts of species like Gershwinia thailandensis and Morbakka sp. from Thai waters remains sparse. This study explores the types and morphology of nematocysts found in the tentacles of these species using light and scanning electron microscopy. We identified three nematocyst types: club-shaped microbasic p-mastigophores, oval isorhizas, and oval microbasic p-rhopaloids. Notably, significant differences in capsule sizes were observed, especially in the microbasic p-mastigophores and isorhizas. The discharge tubules tapered from the proximal to the distal ends, featuring arrow-shaped spines in a helical pattern. A distinct lancet structure was present in both microbasic p-mastigophores and p-rhopaloids. These findings suggest that variations in nematocyst size and morphology may be linked to evolutionary adaptations, functional roles, and venom toxicity. Further research into venom discharge mechanisms could offer valuable insights into the ecological and medical importance of these cnidarians.

Alpha-1-B glycoprotein (A1BG) inhibits sterol-binding and export by CRISP2

Proteins belonging to the CAP superfamily are present in all kingdoms of life and have been implicated in various processes, including sperm maturation and cancer progression. They are mostly secreted glycoproteins and share a unique conserved CAP domain. The precise mode of action of these proteins, however, has remained elusive. Saccharomyces cerevisiae expresses three members of this protein family, which bind sterols in vitro and promote sterol secretion from cells. This sterol-binding and export function of yeast Pry proteins is conserved in the mammalian CRISP proteins and other CAP superfamily members. CRISP3 is an abundant protein of the human seminal plasma and interacts with alpha-1-B glycoprotein (A1BG), a human plasma glycoprotein that is upregulated in different types of cancers. Here we examined whether the interaction between CRISP proteins and A1BG affects the sterol-binding function of CAP family members. Co-expression of A1BG with CAP proteins abolished their sterol export function in yeast and their interaction inhibits sterol-binding in vitro. We map the interaction between A1BG and CRISP2 to the third of five repeated immunoglobulin-like (Ig) domains within A1BG. Interestingly, the interaction between A1BG and CRISP2 requires magnesium, suggesting that coordination of Mg2+ by the highly conserved tetrad residues within the CAP domain is essential for a stable interaction between the two proteins. The observation that A1BG modulates the sterol-binding function of CRISP2, has potential implications for the role of A1BG and related Ig domain containing proteins in cancer progression and the toxicity of reptile venoms containing CRISP proteins.

Sika Deer antler protein antagonizes the inflammatory response and oxidative damage induced by jellyfish venom

The investigation into specific treatments for jellyfish stings has consistently presented a significant medical challenge. Sika Deer antler protein (DAP), a valuable component of traditional Chinese medicine (TCM) known for its various pharmacological properties, has been widely utilized for the prevention and treatment of numerous diseases. In this study, proteome analysis and biological activity assays of DAP identified 94 distinct protein components and demonstrated its capability to scavenge free radicals. Moreover, administration of 50 mg/kg DAP notably enhanced survival rates in mice, mitigated increases in hematological indicators and inflammatory markers (IL-6, IL-1β, and TNF-α), and alleviated pathological abnormalities induced by jellyfish venom. Additionally, DAP intervention significantly decreased the hemolysis rate and improved the viability of RAW264.7 cells, while reducing cell apoptosis and oxidative stress. Transcriptome analysis and western blotting of RAW264.7 cells further confirmed that DAP inhibited the activation of the NF-κB and MAPK signaling pathways. Overall, DAP effectively countered the toxicity of jellyfish venom by reducing oxidative damage and inflammatory response, highlighting the potential of TCM in treating jellyfish stings.

Comparative venom analysis between melanistic and normally coloured phenotypes of the common adder (Vipera berus).

Snake venom is an ecologically relevant functional trait directly linked with a snake's fitness and survival, facilitating predation and defence. Snake venom variation occurs at all taxonomic levels, but the study at the intraspecific level is still in its early stages. The common adder (Vipera berus) exhibits considerable variation in colour phenotypes across its distribution range. Melanistic (fully black) individuals are the subject of myths and fairytales, and in German folklore such 'hell adders' are considered more toxic than their normally coloured conspecifics despite any formal investigation. Here, we provide the first comparative analysis of venoms from melanistic and normally coloured common adders. Specifically, we compared the venom profiles by sodium dodecylsulfate polyacrylamide gel electrophoresis and reversed-phase high-performance liquid chromatography and tested the venoms' protease, phospholipase A2 and cytotoxic activities. Phospholipase A2 activity was similar in both phenotypes, whereas general protease activity was higher in the melanistic venom, which was also more cytotoxic at two concentrations (6.25 and 12.5 µg ml-1). These minor differences between the venoms of melanistic and normally coloured adders are unlikely to be of clinical relevance in the context of human envenomation. In light of our results, the claim that melanistic adders produce more toxic venom than their normally coloured conspecifics appears rooted entirely in folklore.

Proteins from shrews’ venom glands play a role in gland functioning and venom production

Venom production has evolved independently many times in the animal kingdom, although it is rare among mammals. Venomous shrews produce venom in their submandibular salivary glands and use it for food acquisition. Only a few toxins have been identified in shrew venoms thus far, and their modes of action require investigation. The biological and molecular processes relating to venom production and gland functioning also remain unknown. To address this gap, we investigated protein content in extracts from venom glands of two shrew species, Neomys fodiens and Sorex araneus, and interpreted their biological functions. Applying a proteomic approach coupled with Gene Ontology enrichment analysis, we identified 313 and 187 putative proteins in venom glands of N. fodiens and S. araneus, respectively. A search of the UniProt database revealed that most of the proteins found in both shrew species were involved in metabolic processes and stress response, while GO enrichment analysis revealed more stress-related proteins in the glands of S. araneus. Molecules that regulate molecule synthesis, cell cycles, and cell divisions are necessary to enable venom regeneration and ensure its effectiveness in predation and food hoarding. The presence of proteins involved in stress response may be the result of shrews’ high metabolic rate and the costs of venom replenishment. Some proteins are likely to promote toxin spreading during envenomation and, due to their proteolytic action, reinforce venom toxicity. Finally, finding numerous proteins involved in immune response suggests a potential role of shrew venom gland secretions in protection against pathogens. These findings open up new perspectives for studying biological functions of molecules from shrew venom glands and extend our knowledge on the functioning of eulipotyphlan venom systems. Because the majority of existing and putative venomous mammals use oral venom systems to inject venom into target species, the methods presented here provide a promising avenue for confirming or discovering new taxa of venomous mammals.

Lethality associated with snake venom exposure can be predicted by temperature drop in Swiss mice

Establishing humane endpoints to minimize animal suffering in studies on snake venom toxicity and antivenom potency tests is crucial. Our findings reveal that Swiss mice exhibit early temperature drop following exposure to different snake venoms and combinations of venoms and antivenoms, predicting later mortality. Evaluating temperature we can identify within 3 h post-inoculation, the animals that will not survive in a period of 48 h. Implementing temperature as a criterion would significantly reduce animal suffering in these studies without compromising the outcomes.

Renal and Hemorrhagic Complications Following Bee Sting Envenomation: A Case Report from the Hospital of Zinder

Renal and hemorrhagic complications following envenomation by bee stings are rare, posing significant problems for early diagnosis and treatment in the clinical setting. Bee venom is generally well tolerated. A 44-year-old patient was admitted to the infectious and tropical diseases department of the Zinder National Hospital with cervicofacial edema following bee stings. Initially, the patient lost consciousness. Respiratory symptoms included dyspnea and 91% desaturation on room air. The patient was put on oxygen to alleviate hypoxia, doxycycline to prevent secondary bacterial infections, and prednisone to reduce inflammation. The clinical picture was complicated by a worsening of the patient's condition due to a deterioration in renal function, and the subsequent appearance of hematemesis. A renal biopsy revealed acute tubulointerstitial nephropathy, due to direct venom toxicity on the tubules. He was discharged after 35 days. We report a rare case of bee sting complicated by hemorrhagic syndrome and renal involvement.

A Comparative Analysis of the Cytotoxic and Vascular Activity Effects of Western Diamondback Rattlesnake (Crotalus atrox) and Eastern Diamondback Rattlesnake (Crotalus adamanteus) Venoms Using a Chick Embryo Model.

Crotalus snakebites induce various toxicological effects, encompassing neurological, myotoxic, and cytotoxic symptoms, with potentially fatal outcomes. Investigating venom toxicity is essential for public health, and developing new tools allows for these effects to be studied more comprehensively. The research goals include the elucidation of the physiological consequences of venom exposure and the assessment of toxicity using animal models. Chicken embryos serve as valuable models for assessing venom toxicity through the chick embryotoxicity screening test (CHEST) and the chick chorioallantoic membrane (CAM) assay, particularly useful for evaluating vascular impacts. C. adamanteus venom application resulted in higher embryotoxicity and morphological abnormalities, such as Siamese twins. The CAM assay demonstrated the hemorrhagic effects of venom, varying with venom type and concentration. The irritant potential of both venom types was classified as slight or moderate depending on their concentration. Additionally, acetylcholinesterase (AChE) activity was performed to receive information about organ toxicity. The results show that both venoms induced changes in the whole embryo, heart, and liver weights, but the C. adamanteus venom was identified as more toxic. Specific venom concentrations affected AChE activity in embryonic tissues. These findings underscore the embryotoxic and vasoactive properties of Crotalus venoms, providing valuable insights into their mechanisms of toxicity and potential applications in biomedicine.

Inhibition of the Naja naja venom toxicity by polymeric nanoparticles loaded with Leucas aspera methanolic extract.

Snakebite is a neglected tropical disease that affects millions of people worldwide. Developing effective treatments can make a significant contribution to global health efforts and public health initiatives. To reduce mortality due to snakebite, there is an immediate need to explore novel and effective treatment methodologies. In that context, nanoparticle-based drug delivery is gaining a lot of attention. Hydrophilic nanoparticles are suitable for the delivery of therapeutic peptides, proteins, and antigens. The present investigation is aimed at evaluating the anti-ophidian potential of the methanolic extract of the ethno-medicinal herb Leucas aspera (Willd.) loaded within chitosan nanoparticles (CNP-LA), against the Indian cobra (Naja naja) venom enzymes. For this purpose, nanoparticles were prepared using the ionic gelation method to enhance the efficacy of the extract. The physicochemical and structural features of nanoparticles were investigated using dynamic light scattering (DLS), Fourier-transform Infrared (FTIR), field emission scanning electron microscopy (FE-SEM), and X-ray diffraction (XRD) techniques. It was found that CNP-LA has an average size of 260nm with a polydispersity index of 0.132 (PDI) and zeta potential of 34.7 mV, with an encapsulation efficiency of 92.46%. The in vitro release study was performed at pH 5.0 and 7.4. Furthermore, in vitro studies indicated that CNP-LA inhibited the phospholipase A2, hemolytic, and caseinolytic activities of Naja naja venom with the percentage inhibition of 92.5%, 83.9%, and 94.5%, respectively. This is the first report on the application of herbal methanolic extract loaded within chitosan nanoparticles for neutralizing snake venom enzymes with increased efficiency.

Proteomic analysis and lethality of the venom of Aegaeobuthus nigrocinctus, a scorpion of medical significance in the Middle East

The scorpion Aegaeobuthus nigrocinctus inhabits areas in Turkey and the Levant region of the Middle East where severe/lethal envenomings have been reported. Previous research indicated its extreme venom lethality to vertebrates and distinct envenomation syndrome. We report on the composition of A. nigrocinctus venom from Lebanese specimens using nESI-MS/MS, MALDI-TOF MS, SDS-PAGE and RP-HPLC. Venom lethality in mice was also assessed (LD50 = 1.05 (0.19–1.91) mg/kg, i.p), confirming A. nigrocinctus venom toxicity from Levantine populations. Forty-seven peaks were resolved using RP-HPLC, 25 of which eluted between 20 and 40 % acetonitrile. In reducing SDS-PAGE, most predominant components were <10 kDa, with minor components at higher molecular masses of 19.6, 26.1, 46.3 and 57.7 kDa. MALDI-TOF venom fingerprinting detected 20 components within the 1,000–12,000 m/z range. Whole venom ‘shotgun’ bottom-up nLC-MS/MS approach, combined with in-gel tryptic digestion of SDS-PAGE bands, identified at least 67 different components belonging to 15 venom families, with ion channel-active components (K+ toxins (23); Na+ toxins (20); Cl− toxins (2)) being predominant. The sequence of a peptide (named α-KTx9.13) ortholog to Leiurus hebraeus putative α-KTx9.3 toxin was fully determined, which exhibited 81–96 % identity to other members of the α-KTx9 subfamily targeting Kv1.x and Ca2+-activated K+ channels. Chlorotoxin-like peptides were also identified. Our study underscores the medical significance of A. nigrocinctus in the region and reveals the potential value of its venom components as lead templates for biomedical applications. Future work should address whether available antivenoms in the Middle East are effective against A. nigrocinctus envenoming in the Levant area.

Highly conserved and extremely variable: The paradoxical pattern of toxin expression revealed by comparative venom-gland transcriptomics of Phalotris (Serpentes: Dipsadidae)

Although non-front fanged snakes account for almost two-thirds of snake diversity, most studies on venom composition and evolution focus exclusively on front-fanged species, which comprise most of the clinically relevant accidents. Comprehensive reports on venom composition of non-front fanged snakes are still scarce for several groups. In this study, we address such shortage of knowledge by providing new insights about the venom composition among species of Phalotris, a poorly studied Neotropical dipsadid genus. Phalotris are known for their specialized venom delivery system and toxic venoms, which can cause life-threatening accidents in humans. We evaluate the venom-gland transcriptome of Phalotris, comparing the following three South American species: P. reticulatus for the Araucaria Pine forests, P. lemniscatus for the Pampa grasslands, and P. mertensi for the Brazilian Cerrado. Our results indicate similar venom profiles, in which they share a high expression level of Kunitz-type inhibitors (KUNZ). On the other hand, comparative analyses revealed substantial differences in the expression levels of C-type lectins (CTL) and snake venom metalloproteinases (SVMP). The diverse set of SVMP and CTL isoforms shows signals of positive selection, and we also identified truncated forms of type III SVMPs, which resemble type II and type I SVMPs of viperids. Additionally, we identified a CNP precursor hosting a proline-rich region containing a BPP motif resembling those commonly detected in viperid venoms with hypotensive activity. Altogether, our results suggest an evolutionary history favoring high expression levels of few KUNZ isoforms in Phalotris venoms, contrasting with a highly diverse set of SVMP and CTL isoforms. Such diversity can be comparable with the venom variability observed in some viperids. Our findings highlight the extreme phenotypic diversity of non-front fanged snakes and the importance to allocate greater effort to study neglected groups of Colubroidea.

Acute toxicity of bee venom from Apis mellifera L. in mice: A histopathological study

Acute toxicity of bee venom from Apis mellifera L. in mice: A histopathological study

Biosynthesis, characterization and antivenom activities of &lt;i&gt;Moringa oleifera&lt;/i&gt; silver nanoparticles: an experimental approach

Moringa oleifera has been previously established to possess neutralizing potentials against Echis ocellatus venom. This study however, investigated the bioefficacy of silver nanoparticles biosynthesized from M. oleifera leaf extract aimed at improving its bioactivity against E. ocellatus venom-induced toxicities using in vivo and in vitro methods. The intrinsic characteristics of the produced M. oleifera-Silver nanoparticles (MO-AgNPs) were carried out using energy dispersive X-ray, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier-transform infrared spectroscopy. Twenty-five male Wistar rats divided randomly into five groups (n=5) were used for the antivenom study. Group 1 received saline while groups 2 to 5 were envenomed intraperitoneally with 0.22mg/kg (LD50) of E. ocellatus venom. Group 2 was left untreated while groups 3 to 5 were treated with 0.2ml of antivenom, 5 and 10mg/kg MO-AgNPs post-envenomation, respectively. Blood and tissue of treated rats were analyzed for heamatological parameters and histopathology, respectively. The MO-AgNPs formation was confirmed with a colour change from light brown to yellowish-brown with maximum SPR band at 420nm from UV-Vis analysis, indicating a reflection of the bio-reduction of Ag+ to Ag0. The Transmission electron micrographs showed well dispersed spherical AgNPs with average particle size of 15.7nm. Treatment with MO-AgNPs caused a significant improvement of acute anemia, leucopenia and thrombocytopenia induced by the venom in the envenomed treated rats. Also, MO-AgNPs inhibited the haemorrhagic, haemolytic and anticoagulant activities of the venom. Tissue lesions observed in heart of envenomed untreated rats were attenuated after treatment with MO-AgNPs. The biosynthesized MO-AgNPs exhibited potent neutralizing potentials than M. oleifera crude extract against E. ocellatus venom toxicities.

Assessment of the Artemia salina toxicity assay as a substitute of the mouse lethality assay in the determination of venom-induced toxicity and preclinical efficacy of antivenom

Mice are routinely used in snake venom research but are costly and subject to pain and suffering. The crustacean Artemia salina could be an alternative to mice, but data to support its adoption in snake venom research is limited. The aim of the present study was to evaluate the suitability of A. salina as a surrogate of mice in assessing the toxicity of venoms and the preclinical efficacy of antivenoms. The toxicity of venoms from 22 snakes of medical importance in sub–Saharan Africa was evaluated in mice (intraperitoneally; i.p. and intravenously; i.v.) and in A. salina. Subsequently, the capacity of a commercial antivenom to neutralize the toxicity of these venoms in mice and A. salina was investigated. There was a positive correlation between the i.v. median lethal doses (LD50s) and the i.p. LD50s in mice (r = 0.804; p < 0.0001), a moderate correlation between the i.v. LD50s in mice and the median lethal concentrations (LC50s) in A. salina (r = 0.606; p = 0.003), and a moderate correlation between the i.p. LD50s in mice and the LC50s in A. salina (r = 0.426; p = 0.048). Moreover, there was a strong correlation between the i.p. median effective doses (ED50s) and the i.v. ED50s in mice (r = 0.941, p < 0.0001), between the i.p. ED50s in mice and the ED50s in A. salina (r = 0.818, p < 0.0001), and between the i.v. ED50s in mice and the ED50s in A. salina (r = 0.972, p < 0.0001). These findings present A. salina as a promising candidate for reducing reliance on mice in snake venom research. Future investigations should build upon these findings, addressing potential limitations and expanding the scope of A. salina in venom research and antivenom development.

The Cloning and Characterization of a Three-Finger Toxin Homolog (NXH8) from the Coralsnake Micrurus corallinus That Interacts with Skeletal Muscle Nicotinic Acetylcholine Receptors.

Coralsnakes (Micrurus spp.) are the only elapids found throughout the Americas. They are recognized for their highly neurotoxic venom, which is comprised of a wide variety of toxins, including the stable, low-mass toxins known as three-finger toxins (3FTx). Due to difficulties in venom extraction and availability, research on coralsnake venoms is still very limited when compared to that of other Elapidae snakes like cobras, kraits, and mambas. In this study, two previously described 3FTx from the venom of M. corallinus, NXH1 (3SOC1_MICCO), and NXH8 (3NO48_MICCO) were characterized. Using in silico, in vitro, and ex vivo experiments, the biological activities of these toxins were predicted and evaluated. The results showed that only NXH8 was capable of binding to skeletal muscle cells and modulating the activity of nAChRs in nerve-diaphragm preparations. These effects were antagonized by anti-rNXH8 or antielapidic sera. Sequence analysis revealed that the NXH1 toxin possesses eight cysteine residues and four disulfide bonds, while the NXH8 toxin has a primary structure similar to that of non-conventional 3FTx, with an additional disulfide bond on the first loop. These findings add more information related to the structural diversity present within the 3FTx class, while expanding our understanding of the mechanisms of the toxicity of this coralsnake venom and opening new perspectives for developing more effective therapeutic interventions.

Divergence in toxin antigenicity and venom enzymes in Tityus melici, a medically important scorpion, despite transcriptomic and phylogenetic affinities with problematic Brazilian species

The Brazilian scorpion Tityus melici, native to Minas Gerais and Bahia, is morphologically related to Tityus serrulatus, the most medically significant species in Brazil. Despite inhabiting scorpion-envenomation endemic regions, T. melici venom remains unexplored. This work evaluates T. melici venom composition and function using transcriptomics, enzymatic activities, and in vivo and in vitro immunological analyses. Next-Generation Sequencing unveiled 86 components putatively involved in venom toxicity: 39 toxins, 28 metalloproteases, seven disulfide isomerases, six hyaluronidases, three phospholipases and three amidating enzymes. T. serrulatus showed the highest number of toxin matches with 80–100 % sequence similarity. T. melici is of medical importance as it has a venom LD50 of 0.85 mg/kg in mice. We demonstrated venom phospholipase A2 activity, and elevated hyaluronidase and metalloprotease activities compared to T. serrulatus, paralleling our transcriptomic findings. Comparison of transcriptional levels for T. serrulatus and T. melici venom metalloenzymes suggests species-specific expression patterns in Tityus. Despite close phylogenetic association with T. serrulatus inferred from COI sequences and toxin similarities, partial neutralization of T. melici venom toxicity was achieved when using the anti-T. serrulatus antivenom, implying antigenic divergence among their toxins. We suggest that the Brazilian therapeutic scorpion antivenom could be improved to effectively neutralize T. melici venom.

Inhibition of Bungarus caeruleus snake venom toxicity by Citrus reticulata methanolic extract and in-silico analysis of possible binding modes

Inhibition of Bungarus caeruleus snake venom toxicity by Citrus reticulata methanolic extract and in-silico analysis of possible binding modes