title: Microvesicles in the venom of Crotalus durissus terrificus (Serpentes, Viperidae).
abstract: Microvesicles with electron-dense content are consistently observed by transmission electron microscopy on the luminal face of secretory cells of venom glands of viperid snakes. In this work, we evaluated their presence in Crotalus durissus terrificus venom glands and also in freshly collected venom. Microvesicles were found in the venom glands mainly in regions of exocytosis. They ranged from 40 to 80 nm in diameter. Freeze-fracture replicas of the glands revealed particles on the cytoplasmic leaflet (P-face) of these vesicles, suggesting that they carry transmembrane proteins. Vesicles separated by ultracentrifugation from cell-free venom were similar in size and structure to the microvesicles observed in the glands. A fine fuzzy coat surrounded each microvesicle. The function of these venom vesicles is still unknown, but they may contribute to inactivation of stored venom components, or their activation after the venom is released.
authors.affiliation: Laboratório de Biologia Celular, Instituto Butantan, Av. Vital Brasil, 1500, São Paulo, SP 05503-900, Brasil. sycarneiro@butantan.gov.br
authors.forename: Sylvia Mendes
authors.initials: SM
authors.lastname: Carneiro
authors.forename: Wilson
authors.initials: W
authors.lastname: Fernandes
authors.forename: Sávio Stefanini
authors.initials: SS
authors.lastname: Sant'Anna
authors.forename: Norma
authors.initials: N
authors.lastname: Yamanouye
mesh_terms: D000818:Animals; D021961:Cell Membrane Structures / Q000648:ultrastructure*; D046529:Microscopy, Electron, Transmission; D014757:Viper Venoms / Q000096:biosynthesis*; D017819:Viperidae
chemical_list: D014757:Viper Venoms