Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon

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  Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon Abstract Snakes exhibit extreme cranial kinesis that facilitates ingestion of prey with large cross-sectional area, but this ability is widely predicted to reduce bite performance due to decreased structural rigidity. Consequently, most large-bodied snakes rely on envenomation or constriction to subdue prey prior to ingestion. Species within the genus Drymarchon represent a notable exception: these large, non-venomous, non-constricting snakes routinely consume a wide range of prey, including large and potentially dangerous vertebrates, using only simple seizing and pinioning behaviors. Here, we quantify bite performance in three species of Drymarchon ( D. corais, D. couperi, and D. melanurus ), examine morphological predictors of biting performance, compare biting pressure to constriction pressure in similarly sized snakes, and synthesize dietary records across the genus. Our results sh...

The Crude Venom of the Whitetail Lancehead, Bothrops leucurus, and Two of Its Enzymatic Components Are Selectively Cytotoxic for Glioma Cells In Vitro

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The Crude Venom of the Whitetail Lancehead, Bothrops leucurus, and Two of Its Enzymatic Components Are Selectively Cytotoxic for Glioma Cells In Vitro

ABSTRACT

Malignant glioma is the most common primary brain tumor, and glioblastoma multiforme (GBM) remains its most aggressive and incurable form. Snake venoms contain bioactive compounds with promising antitumoral properties against several cancer types. This study investigated the in vitro antitumor activity of Bothrops leucurus crude venom against rat and human glioma cells and identified two active venom enzymes. The crude venom showed concentration-dependent cytotoxicity, with EC50 values of 2.66 μg/mL for rat glioma cells and 3.60 μg/mL for human U251 glioma cells after 72 h. At 3.0 μg/mL, the venom induced necrotic death in glioma cells, whereas astrocytes remained viable. Two enzymes with anti-glioma activity were identified: the metalloprotease P-III leucurolysin-B and a basic phospholipase A2 (bPLA2). Both enzymes exhibited concentration-dependent cytotoxicity toward C6 and U251 glioma cells. Leucurolysin-B was more potent than bPLA2, presenting EC50 values of 1.44 and 2.25 μg/mL for C6 and U251 cells, respectively, while bPLA2 showed EC50 values of 30.00 and 39.81 μg/mL. Treatment with both enzymes reduced cellularity and induced morphological alterations in glioma cells without affecting healthy human astrocytes, indicating selective activity. Leucurolysin-B primarily induced apoptosis, whereas bPLA2 mainly caused necrosis. These findings demonstrate the antitumor potential of B. leucurus venom, particularly leucurolysin-B, as a promising candidate for glioma therapy development. Overall, the results suggest that venom-derived molecules may represent prototypes for developing therapies against malignant gliomas, combining efficacy with reduced toxicity toward normal glial cells. Further studies are required to clarify their mechanisms of action and evaluate their potential experimentally.

V. Rosário, O. H., Fucase, T. M., Spencer, P. J., Sciani, J. M., Clarêncio, J., Rádis-Baptista, G., Casais-e-Silva, L. L., & El-Bachá, R. S. The Crude Venom of the Whitetail Lancehead, Bothrops leucurus, and Two of Its Enzymatic Components Are Selectively Cytotoxic for Glioma Cells In Vitro. Journal of Applied Toxicology. https://doi.org/10.1002/jat.70409