ABSTRACT
The biological activities of the venom of three species of spiders of the genus Loxosceles were studied (L. gaucho, L. laeta and L. intermedia). The dermonecrotic and lethal activities are shared by all three Loxosceles venoms. Only low levels of proteolytic, myotoxic and phospholipase A2 activities were demonstrable even when a large amount of venom was used. No direct hemolytic activitiy was detected. L. intermedia venom was the most lethal (LD50 0.48 mg/kg), the L. laeta venom was the least lethal (LD50 1.45 mg/kg) whereas L. gaucho venom showed an intermediate value (LD50 0.74 mg/kg). The anti-Loxosceles serum used (anti-arachnidic serum) was able to neutralize the most important activities (i.e., dermonecrotic and lethal activities) of the three venoms. SDS-PAGE and immunoblotting using the anti-arachnidic serum showed that almost all venom antigens were recognized by this antiserum. The possible mechanisms of action of the Loxosceles venom are discussed.
Subject(s)
Animals , Mice , Rabbits , Immune Sera/metabolism , Necrosis , Spider Venoms/chemistry , Spiders/pathogenicity , Lethal Dose 50 , Spider Venoms/toxicityABSTRACT
In this paper further information concerning the ecological and biogeographical aspects of scorpionism is presented. Some of the information already outlined in three previous publications (10,14,16) is assessed, and new data given concerning the pattern of distribution presented by Tityus serrulatus in Brazil. Some new ideas are also proposed regarding the possible evolutionary advantages and disadvantages of parthenogenesis versus sexuality in both the short-term and the long-term.
Subject(s)
Animals , Brazil , Residence Characteristics , Ecology , Parthenogenesis , Reproduction , Scorpions , Spider Bites/epidemiologyABSTRACT
Foram analisados 242 acidentes atribuídos a aranhas do gênero Loxosceles Heinecken & Lowe atendidos no Hospital Vital Brazil do Instituto Butantan (1980-1984). L. gaucho Gertsch foi o agente agresssor mais comum e a espécie capturada com maior frequência nos locais de acidente vistoriados. L. laeta e L. intermedia Mello-Leitäo também estiveram representados no material estudado. Noçöes de reconhecimento e biologia dessas aranhas assim como a distribuiçäo geográfica das espécies brasileiras foram incluídas, para orientaçäo de médicos e pessoal relacionado a acidentes por animais peçonhentos. Os sinais característicos de síndrome loxoscélica e sua frequência na casuística em estudo foram mencionados e uma comparaçäo foi feita com dados correspondentes encontrados na literatura sulamericana