Hunting ecology predicts eye arrangements in the modular visual system of spiders

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  Hunting ecology predicts eye arrangements in the modular visual system of spiders Summary Vision is one of the most important senses used by animals and contributes to fundamental behaviors, including foraging, navigation, and mate detection and selection. 1 Although much is known about how eye position and orientation correlate to ecology in the context of binocularity, 2 animals with multipartite visual systems (more than two eyes) remain comparatively neglected. Spiders are highly successful predators that occupy a range of ecological niches and usually possess eight eyes. Here, we use three-dimensional geometric morphometrics and evolutionary modeling to test whether eye positions, orientations, and interocular angles correlate with hunting strategies in 52 species across the spider phylogeny. We demonstrate that eye configurations diversified from an ancestral medial cluster, as seen in modern trapdoor spiders, to a halo-like configuration in orb-weavers, and to the fronta...

In vitro inhibition of snake venom toxins by varespladib, marimastat, nafamostat and dimercaprol

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By Holger Krisp - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=17574465

In vitro inhibition of snake venom toxins by varespladib, marimastat, nafamostat and dimercaprol

Abstract

Snakebite envenoming causes more than 130,000 deaths and more than 400,000 disabilities per year and has been classified as a priority Neglected Tropical Disease by the World Health Organization (WHO). While antivenom therapy remains the mainstay of snakebite treatment, small molecule therapeutics (SMTs) have been proposed as potential adjuncts to antivenom, particularly as oral treatment in the prehospital setting. Several SMTs have demonstrated efficacy in preclinical models of snakebite envenoming, with varespladib, a secreted phospholipase A2 (sPLA2) inhibitor, being granted orphan drug status for its potential to treat snakebite. The present study investigated the potential of four SMTs (e.g., varespladib, marimastat, nafamostat and dimercaprol) to neutralise toxic components present in the venom of southern African snake species. In vitro experimentation found that varespladib potently inhibited snake venom phospholipase A2 (svPLA2) activity in Bitis arietans (IC50 = 0.221 μM) and B. gabonica (IC50 = 0.276 μM). Marimastat exhibited potent inhibition of snake venom metalloproteinase (svMP) in several snake species with IC50 values ranging from 0.0042–3.06 μM, while dimercaprol, a metal chelator, was a lower potency svMP inhibitor with IC50 values ranging from 5.01–79.8 μM. Nafamostat proved to be an inhibitor of snake venom serine protease (svSP) in B. arietans (IC50 = 3.72 μM), B. gabonica (IC50 = 3.80 μM) and Causus rhombeatus (IC50 = 0.261 μM). These data demonstrate that SMTs are effective inhibitors of the relevant enzymes in several snake species and support the proposal that SMTs could be developed for therapeutic intervention in snakebite envenoming.
Le Roux, A., Cloete, S. J., Petzer, J. P., & Petzer, A. (2025). In vitro inhibition of snake venom toxins by varespladib, marimastat, nafamostat and dimercaprol. Toxicon, 108626. https://doi.org/10.1016/j.toxicon.2025.108626