Venom production and secretion in reptiles

Abstract

The venom glands of reptiles, particularly those of front-fanged advanced snakes, must satisfy conflicting biological demands: rapid synthesis of potentially labile and highly toxic proteins, storage in the gland lumen for long periods, stabilization of the stored secretions, immediate activation of toxins upon deployment and protection of the animal from the toxic effects of its own venom. This dynamic system could serve as a model for the study of a variety of different phenomena involving exocrine gland activation, protein synthesis, stabilization of protein products and secretory mechanisms. However, these studies have been hampered by a lack of a long-term model that can be propagated in the lab (as opposed to whole-animal studies). Numerous attempts have been made to extend the lifetime of venom gland secretory cells, but only recently has an organoid model been shown to have the requisite qualities of recapitulation of the native system, self-propagation and long-term viability (>1 year). A tractable model is now available for myriad cell- and molecular-level studies of venom glands, protein synthesis and secretion. However, venom glands of reptiles are not identical, and many differ very extensively in overall architecture, microanatomy and protein products produced. This Review summarizes the similarities among and differences between venom glands of helodermatid lizards and of rear-fanged and front-fanged snakes, highlighting those areas that are well understood and identifying areas where future studies can fill in significant gaps in knowledge of these ancient, yet fascinating systems.

Extracellular Vesicles from Bothrops jararaca Venom Are Diverse in Structure and Protein Composition and Interact with Mammalian Cells

“…In viperid snakes, venom is stored for long periods in the extracellular space, in the large venom gland basal lumen [98,99]. Several toxins lose their prodomain and undergo maturation and post-translational modifications after reaching the lumen of the venom gland.…”

Comparative morphology of oral glands in snakes of the family Homalopsidae reveals substantial variation and additional independent origins of salt glands within Serpentes

“…Many putative or established functions are attributed to these oral glands, such as venom production, mouth lubrication, antimicrobial activity, and salt excretion (Jackson et al., 2017). Despite recent advances in the study of oral glands and their secretions (Fry et al., 2012; Jackson et al., 2019; Mackessy, 2022; Oliveira & Zaher, 2022), morphological variation in these glands and their functions remains poorly known for most snake families.…”

“…Eight or so distinct oral glands are documented for snakes, including venom, supra-and infralabial, sublingual, and premaxillary glands (Oliveira & Zaher, 2022). Many putative or established functions are attributed to these oral glands, such as venom production, mouth lubrication, antimicrobial activity, and salt excretion (Jackson et al, 2017).Despite recent advances in the study of oral glands and their secretions (Fry et al, 2012;Jackson et al, 2019;Mackessy, 2022;Oliveira & Zaher, 2022), morphological variation in these glands and their functions remains poorly known for most snake families.The mud snakes (Homalopsidae) are little-studied and generally poorly known, with many outstanding questions about their phylogeny and evolutionary biology (…”

“…Despite recent advances in the study of oral glands and their secretions (Fry et al, 2012;Jackson et al, 2019;Mackessy, 2022;Oliveira & Zaher, 2022), morphological variation in these glands and their functions remains poorly known for most snake families.…”

First Insights into the Venom Composition of Two Ecuadorian Coral Snakes

“…Micrurus is a wide-ranging genus, found from the southern United States to northern Argentina [ 20 ]. The investigation of coral venoms has been mainly hampered by venom availability [ 21 ]. Only 20% of Micrurus venoms worldwide have been analysed with proteomics approaches [ 22 ] due to the small quantities of venom that we can obtain from these specimens and the difficulties of their adjustment to captive conditions [ 20 ].…”