Poster 259 - Comparative toxic effects of the venoms from three wasp species of the genus Polybia

Poster 259. Congresso da Sociedade Brasileira de Toxinologia, 8., Symposium of the Pan American Section of the International Society on Toxinology, 8., 2004, Angra dos Reis, Brasil. Abstracts... J. Venom. Anim. Toxins incl.Trop. Dis., 2004, 10, 3, p.618.

Comparative toxic effects of the venoms from three wasp species of the genus Polybia (Hymenoptera, Vespidae)

Alexandra Olimpio Siqueira Cunha, Márcia Renata Mortari, Luciana de Oliveira, Erica Aparecida Gelfuso, Eveline Bis Vieira and Wagner Ferreira dos Santos.

In this work we have investigated hemolytic, edematogenic and neurotoxic effects of the crude venoms of P. occidentalis, P. paulista and P. ignobilis. In addition, protein contents and dry weights of these wasp’s venom reservoirs have also been compared. Venom sacs were dissecated from the wasps crushed and centrifuged at 5000 g for 10 min, the supernatant collected was lyophilized, weighted and the protein content was estimated by Lowry methodology. The hemolytic activity was assed according to Ho and Ko (1988) using human washed red cells (25%) and erythrocytes of different species (rat, pigeon, ox, sheep, snake and horse). Edema was induced by a subplantar injection of venom extracts into the left hind paw of sodium thiopental-anesthetized rats. The right hind paw was injected with 15 mM saline to serve as control. Both paws were measured with a plethysmometer. Neurotoxicity was assed by i.c.v. injections of crude venoms using Wistar rats and the LD₅₀ for each venom was calculated by Probit analysis. All parametric data were submitted to analysis of variance (ANOVA). It was used p<0.05 and p<0.001. P. ignobilis presented the highest venom protein content and highest dry weight per worker reservoir. When injected in the hind paw of rats, it evoked a stronger edematogenic effect. The venom of P. paulista showed the most potent hemolytic activity on human washed red blood cells. The three venoms showed marked differences in hemolytic activity according to the species yielding the blood. However, this variability appeared to be similar for the three venoms. Intracerebroventricular injection of each of the three venoms caused similar neurotoxic effects on Wistar rats.

These new data on the composition and pharmacological activity of Polybia wasp venoms should be useful for studies on the activity of these biological control agents.