Efeitos tóxicos de lectina e toxina da alga marinha Solieria filiformis sobre camundongos e Boophilus microplus (carrapatos)

Abstract

The proteins, lectin and toxin of the red marine alga Solieria filiformis were analyzed as for their poisonous effects in mice and in the Boophilus microplus. The crude extract and precipitate F0/70 with sulfate of ammonium of that alga were shown poisonous for mice upon intraperitoneal injection (LD 50 16,5 and 13,8 mg/kg of body weight of the animal), respectively, producing dyspnea, tonic-clonic convulsions and paralysis that preceded the death of the animal. The thermal treatment of the crude extract abolished the poisonous activity (90°C, 60 min). The procedures of purification of the toxin and lectin were driven by precipitation of the crude extract with ammonium sulfate up to 70% of saturation (FO/70), followed by affinity chromatography in column of Manana-Sepharose 48 and gel filtration with Sephadex G-100. The toxin (LD 50 21,7 and 17,8 mg/kg of corporal weight for ip and iv. routes, respectively), was shown to be distinct from of the lectin (LD 50 1,7 and 1,5 mg/kg of corporal weight for ip. and iv. routes, respectively). The lectin was a dimeric protein with apparent molecular mass of 29kDa and the toxin, a monomeric proteic with mass of 13,99 kDa, for PAGE-SDS in the presence of J3-mercaptoetanol. The hystopatologic analysis of the organs after death of the mice injected with the lectin and the toxin revealed a picture of disseminated intravascular coagulation (CIVD), that confirms the toxicity of these proteins. The preliminary evaluations of the lectin and toxin in the control on the tick B. microplus demonstrated that these proteins affected the evolutionary cycle of the ectoparasite inducing toxics effects (reduction of the total weight of the mass of eggs, reduction of the posture periods and mortality). The toxic effects of the lectin were shown to be more intense than those of the toxin.