title: Paralyzing and myotoxic effects of a recombinant bothropstoxin-I (BthTX-I) on mouse neuromuscular preparations.
abstract: As a first step to investigate the structure-function relationship of bothropstoxin-I (BthTX-I), a myotoxin from Bothrops jararacussu snake venom, our group previously cloned a recombinant toxin (rBthTX-I) in Escherichia coli. The aim of this work was to characterize the biological activities of this rBthTX-I (1.0 microM) in both phrenic-diaphragm and extensor digitorum longus preparations in vitro, by means of myographic and morphologic techniques. Native BthTX-I (1.0 microM) was used as a standard. The influence of heparin (27.5 microg/ml) upon the biological activities of both toxins was also investigated. rBthTX-I had similar effects to the native toxin inducing blockage of both directly and indirectly evoked contractions in phrenic-diaphragm preparations, and muscle damage characterized by edema, round fibers, and cell areas devoid of myofibrils. Interestingly the paralyzing activity of rBthTX-I was slightly more potent than the native toxin. Heparin prevented paralyzing and myotoxic effects of both the native and recombinant toxins. This work shows that rBthTX-I was expressed in a fully active form, and presents a biological profile similar to the native toxin.
authors.affiliation: Departamento de Farmacologia, Instituto de Biociências, Universidade Estadual Paulista, Rubião Júnior, Botucatu, CEP 18618-000, São Paulo, Brazil. gallacci@ibb.unesp.br
authors.forename: Márcia
authors.initials: M
authors.lastname: Gallacci
authors.forename: Maristela
authors.initials: M
authors.lastname: Oliveira
authors.forename: Maeli
authors.initials: M
authors.lastname: Dal Pai-Silva
authors.forename: Walter Luís Garrido
authors.initials: WL
authors.lastname: Cavalcante
authors.forename: Patrick Jack
authors.initials: PJ
authors.lastname: Spencer
mesh_terms: D000818:Animals; D017837:Bothrops; D016923:Cell Death; D003435:Crotalid Venoms / Q000633:toxicity*; D003964:Diaphragm / Q000187:drug effects / Q000502:physiology; D004926:Escherichia coli / Q000737:chemistry; D008297:Male; D051379:Mice; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology; D010243:Paralysis / Q000139:chemically induced*; D010791:Phrenic Nerve / Q000187:drug effects / Q000502:physiology; D011994:Recombinant Proteins; D013329:Structure-Activity Relationship
chemical_list: D003435:Crotalid Venoms; D011994:Recombinant Proteins; C078097:bothropstoxin