Venom apparatus of the Brazilian tarantula Vitalius dubius Mello-Leitão 1923 (Theraphosidae)

Abstract

Tarantula venoms are a cocktail of proteins and peptides that have been increasingly studied in recent years. In contrast, less attention has been given to analyzing the structure of the paired cephalic glands that produce the venom. We have used light, electron, and confocal microscopy to study the organization and structure of the venom gland of the Brazilian tarantula Vitalius dubius. The chelicerae are hairy chitinous structures, each with a single curved hollow fang that opens via an orifice on the anterior surface. Internally, each chelicera contains striated muscle fiber bundles that control fang extension and retraction, and a cylindrical conical venom gland surrounded by a thick well-developed layer of obliquely arranged muscle fibers. Light microscopy of longitudinal and transverse sections showed that the gland secretory epithelium consists of a sponge-like network of slender epithelial cell processes with numerous bridges and interconnections that form lacunae containing secretion. This secretory epithelium is supported by a basement membrane containing elastic fibers. The entire epithelial structure of the venom-secreting cells is reinforced by a dense network of F-actin intermediate filaments, as shown by staining with phalloidin. Neural elements (axons and acetylcholinesterase activity) are also associated with the venom gland. Transmission electron microscopy of the epithelium revealed an ultrastructure typical of secretory cells, including abundant rough and smooth endoplasmic reticulum, an extensive Golgi apparatus, and numerous mitochondria.

Partial Characterization of Venom from the Colombian Spider Phoneutria Boliviensis (Aranae:Ctenidae)

“…These heterogeneous mixtures are considered a rich source of low molecular mass compounds displaying antimicrobial activities [ 12 ], with the most abundant reports of neurotoxic peptides with high contents of cysteine (Cys) residues, affecting a great variety of presynaptic ion channels [ 13 ]. These peptide-like components can be divided into three groups: low molecular mass components (<1 kDa–acylpolyamines and linear cytolytic peptides), medium molecular mass components (<10 kDa), and high molecular mass components (>10 kDa) [ 14 ] enhancing neurotoxic or cytotoxic activity [ 6 , 15 , 16 ].…”

Pharmacological Characterization of the Edema Caused by Vitalius dubius (Theraphosidae, Mygalomorphae) Spider Venom in Rats

“…We have previously reported on the venom gland structure (Rocha-e-Silva et al, 2009a) and general venom composition (Rocha-e-Silva et al, 2009b) of V. dubius. We have also isolated a nicotinic receptor antagonist (Rocha-e-Silva et al, 2013) and hyaluronidase (Sutti et al, 2014) from this venom.…”

Beyond spider personality: The relationships between behavioral, physiological, and environmental factors

“…In addition, differences in the quantity and quality of venom are affected by different intrinsic factors (e.g., hunger level, Hayes, 1993; life‐history stage; Herzig, 2010), metabolic rate (Kowalski & Rychlik, 2018), hormone concentration (Gomes & Palma, 2016; Lira et al., 2017; Zhang et al., 2017), body size (Fox, 2018; Rocha‐e‐Silva et al., 2009), genes (Case well et al., 2013; Hargreaves et al., 2014), sex (Zobel‐Thropp et al., 2018), and/or ontogeny (Boevé et al., 1995). For example, sexual dimorphism in venom profiles is seen in the orb‐weaver, Tetragnatha versicolor , which is thought to play a role in sexual communication (Zobel‐Thropp et al., 2018), while venom composition in the tarantula Phlogius crassipes changes during development from the juvenile stage through to adulthood and continues to change throughout adulthood (Santana et al., 2017).…”

“…In addition, differences in the quantity and quality of venom are affected by different intrinsic factors (e.g., hunger level, Hayes, 1993;life-history stage;Herzig, 2010), metabolic rate (Kowalski & Rychlik, 2018), hormone concentration (Gomes & Palma, 2016;Lira et al, 2017;Zhang et al, 2017), body size (Fox, 2018;Rocha-e-Silva et al, 2009), genes (Case well et al, 2013;Hargreaves et al, 2014), sex (Zobel-Thropp et al, 2018), and/or ontogeny (Boevé et al, 1995).…”