Extensive Variation in the Activities of Pseudocerastes and Eristicophis Viper Venoms Suggests Divergent Envenoming Strategies Are Used for Prey Capture

Abstract

Snakes of the genera Pseudocerastes and Eristicophis (Viperidae: Viperinae) are known as the desert vipers due to their association with the arid environments of the Middle East. These species have received limited research attention and little is known about their venom or ecology. In this study, a comprehensive analysis of desert viper venoms was conducted by visualising the venom proteomes via gel electrophoresis and assessing the crude venoms for their cytotoxic, haemotoxic, and neurotoxic properties. Plasmas sourced from human, toad, and chicken were used as models to assess possible prey-linked venom activity. The venoms demonstrated substantial divergence in composition and bioactivity across all experiments. Pseudocerastes urarachnoides venom activated human coagulation factors X and prothrombin and demonstrated potent procoagulant activity in human, toad, and chicken plasmas, in stark contrast to the potent neurotoxic venom of P. fieldi. The venom of E. macmahonii also induced coagulation, though this did not appear to be via the activation of factor X or prothrombin. The coagulant properties of P. fieldi and P. persicus venoms varied among plasmas, demonstrating strong anticoagulant activity in the amphibian and human plasmas but no significant effect in that of bird. This is conjectured to reflect prey-specific toxin activity, though further ecological studies are required to confirm any dietary associations. This study reinforces the notion that phylogenetic relatedness of snakes cannot readily predict venom protein composition or function. The significant venom variation between these species raises serious concerns regarding antivenom paraspecificity. Future assessment of antivenom is crucial.

Malaysian and Chinese King Cobra Venom Cytotoxicity in Melanoma and Neonatal Foreskin Fibroblasts Is Mediated by Age and Geography

“…We used human melanoma cells (MM96L) and human neonatal foreskin fibroblasts (NFFs), supplied by QIMR Berghofer Medical Research Institute. Cells were maintained in RPMI medium supplemented with 1% penicillin–streptomycin and foetal calf serum (FCS), as previously described [ 6 , 42 , 43 ]. Cell viability was evaluated using colourimetric MTT (Thiazolyl Blue Tetrazolium Bromide; Sigma-Aldrich, St Louis, MO, USA) assays [ 6 , 42 , 43 ].…”

“…Cells were maintained in RPMI medium supplemented with 1% penicillin–streptomycin and foetal calf serum (FCS), as previously described [ 6 , 42 , 43 ]. Cell viability was evaluated using colourimetric MTT (Thiazolyl Blue Tetrazolium Bromide; Sigma-Aldrich, St Louis, MO, USA) assays [ 6 , 42 , 43 ]. The following venom concentrations of 1 µg/mL, 2.5 µg/mL, 5 µg/mL, 10 µg/mL, or 50 µg/mL were added to cells ( n = 4) and incubated for 24 h or 48 h. We used 10% of dimethyl sulfoxide (DMSO) as a positive control (100% toxicity).…”

“…This biochemical complexity underpins the striking diversity in toxin expression found across species, populations, and even within individuals throughout their lifetime [ 5 ]. This variability deepens the reservoir of pharmacological potential while highlighting new medical applications [ 6 ].…”

“…Snake venoms function at the ecological and biochemical interface between predator and prey, aiming mainly to facilitate predation [ 7 ]. This has led investigations of drivers in snake venom variation to focus on prey preferences [ 6 , 8 , 9 , 10 ]. However, this approach overlooks the ecological complexity that underlies the evolution of a phenotype.…”

The Dragon’s Paralysing Spell: Evidence of Sodium and Calcium Ion Channel Binding Neurotoxins in Helodermatid and Varanid Lizard Venoms

“…Therefore, to fill these knowledge gaps, we investigated the neuropathology of helodermatid and varanid lizard venoms. To observe the effects on whole receptors, we used the Gallus gallus chick biventer nerve-muscle preparation assay, an avian skeletal muscle preparation well-validated through numerous studies on snake venoms [18,[53][54][55][56]. To determine the binding affinity of the venoms for various ion channels, we used biolayer interferometry to ascertain binding to the voltage-sensing domain IV S3-S4 extracellular loop mimotopes for human sodium and calcium channels, an approach validated using venoms as diverse as snakes and stonefish [57][58][59][60][61][62][63].…”