Aislamiento y caracterización bioquímica y toxicológica de una fosfolipasa acída del veneno de Bothrops Asper
Cargando...
Archivos
Fecha
2010
Autores
Director
Título de la revista
ISSN de la revista
Título del volumen
Publicador
Páginas
Resumen
Las fosfolipasas A2 (PLA2s) son uno de los principales componentes de los venenos de serpiente y ejercen una gran variedad de actividades tóxicas como neurotoxicidad y miotoxicidad, entre otras. Dado que la mayoría de PLA2s tóxicas son proteínas básicas, las isoformas acídicas y sus posibles papeles en los venenos son menos conocidos. En este trabajo, una enzima acídica (BaspPLA2-II) fue aislada del veneno de Bothrops asper (región del Pacífico de Costa Rica) y caracteriz.ada. BaspPLAi-II es monomérica, con una masa de 14.212±6 Da y un punto isoeléctrico de 4,9. Su secuencia completa de 124 aminoácidos se dedujo a través de su ADN copia y mediante la secuenciación automatizada de sus aminoácidos. Pertenece al grupo Asp49, de enzimas catalíticamente activas. Ensayos in vivo e in vitro demostraron que BaspPLA2-II, en contraste con las PLA2s básicas Asp49 presentes en el mismo veneno, carece de actividad miotóxica, citotóxica y anticoagulante. La enzima BaspPLA2-II también se diferenció de otras PLA2s acfdicas descritas en venenos de Bothrops spp., ya que no generó hipotensión ni inhibición de la agregación plaquetaria. Además, esta enzima no fue letal para ratones, con dosis intravenosas de hasta 100 μg (5,9 μg/g), lo que indica su falta de actividad neurotóxica. El único efecto tóxico registrado in vivo fue una inducción moderada de edema local. Por lo tanto, las características toxicológicas de BaspPLA2-II sugieren que no juega un papel clave en la fisiopatología del envenenamiento por B. asper y que su papel estaría limitado a funciones digestivas. Los análisis inmunoquímicos con anticuerpos contra BaspPLAi-II revelaron que las PLA2s acíclicas y básicas forman dos grupos antigénicamente diferentes en el veneno de B. asper.
Inglés: Phospholipases A2 (PLA2s) are major components of snake venoms, exerting a variety of relevant toxic actions such as neurotoxicity and myotoxicity, among others. Since the majority of toxic PLA2s are basic proteins, acidic isoforms and their possible roles in venoms are Iess understood. In this study, an acidic enzyme (BaspPLA2-ID was isolated from the venom of Bothrops asper (Pacific region of Costa Rica) and characterized. BaspPLAi-II is monomeric, with a mass of 14,212±6 Da anda pl of 4.9. Its complete sequence of 124 amino acids was deduced through cDNA and protein sequencing, showing that it belongs to the Asp49 group of catalytically active enzymes. In vivo and in vitro assays demonstrated that BaspPLA2-II, in contrast to the basic Asp49 counterparts present in the same venom, lacks myotoxic, cytotoxic, and anticoagulant activities. BaspPLA2-II also differed from other acidic PLA2s described in Bothrops spp. venoms, as it did not show hypotensive and anti-platelet aggregation activities. Furthermore, this enzyme was not lethal to mice at intravenous doses up to 100 μg (5.9 μg/g), indicating its lack of neurotoxic activity. Toe only toxic effect recorded in vivo was a moderate induction of local edema Therefore, the toxicological characteristics of BaspPLAi-II suggest that it does not play a key role in the pathophysiology of envenomings by B. asper, and that its purpose might be restricted to digestive functions. Immunochemical analyses using antibodies raised against BaspPLA2-II revealed that acidic and basic PLA2s form two di:fferent antigenic groups in B. asper venom.
Inglés: Phospholipases A2 (PLA2s) are major components of snake venoms, exerting a variety of relevant toxic actions such as neurotoxicity and myotoxicity, among others. Since the majority of toxic PLA2s are basic proteins, acidic isoforms and their possible roles in venoms are Iess understood. In this study, an acidic enzyme (BaspPLA2-ID was isolated from the venom of Bothrops asper (Pacific region of Costa Rica) and characterized. BaspPLAi-II is monomeric, with a mass of 14,212±6 Da anda pl of 4.9. Its complete sequence of 124 amino acids was deduced through cDNA and protein sequencing, showing that it belongs to the Asp49 group of catalytically active enzymes. In vivo and in vitro assays demonstrated that BaspPLA2-II, in contrast to the basic Asp49 counterparts present in the same venom, lacks myotoxic, cytotoxic, and anticoagulant activities. BaspPLA2-II also differed from other acidic PLA2s described in Bothrops spp. venoms, as it did not show hypotensive and anti-platelet aggregation activities. Furthermore, this enzyme was not lethal to mice at intravenous doses up to 100 μg (5.9 μg/g), indicating its lack of neurotoxic activity. Toe only toxic effect recorded in vivo was a moderate induction of local edema Therefore, the toxicological characteristics of BaspPLAi-II suggest that it does not play a key role in the pathophysiology of envenomings by B. asper, and that its purpose might be restricted to digestive functions. Immunochemical analyses using antibodies raised against BaspPLA2-II revealed that acidic and basic PLA2s form two di:fferent antigenic groups in B. asper venom.
Descripción
Tesis (magister scientiae en microbiología)--Universidad de Costa Rica. Sistema de Estudios de Posgrado, 2010
Palabras clave
MIOTOXINAS - TOXICOLOGIA, SERPIENTES VENENOSAS, TERCIOPELO (SERPIENTES), VENENOS ANIMALES - ANALISIS