ABSTRACT
Megalopygids Megalopyge lanata and Podalia orsilochus are common causative agents of accidents in agricultural workers. These accidents are provoked by dermal contact at their larval stage and are characterized by cutaneous reactions, such as burning pain, edema and erythema, typically mild and self-limited. There is very little information about their venoms and their toxicological implications on human health. Thus, we employed proteomic techniques and biological assays to characterize venoms (bristle extracts) from caterpillars of both species collected from Misiones, Argentina. The electrophoretic profiles of both venoms were substantially different, and they presented proteins related to toxicity, such as serinepeptidases, serpins and lectins. P. orsilochus venom exhibited higher caseinolytic activity than M. lanata venom, agreeing with the fact that only P. orsilochus venom hydrolyzed human fibrin(ogen). In addition, the latter shortened the clotting time triggered by calcium. While the venom of M. lanata induced a mild inflammatory lesion in mouse skin, P. orsilochus venom caused prominent necrosis, inflammatory infiltration and hemorrhage at the site of venom injection. On the other hand, P. orsilochus venom was better recognized by Lonomia obliqua antivenom, although many of its proteins could not be cross-reacted, what may explain the difference in the clinical manifestations between accidents by Podalia and those by Lonomia. Altogether, this study provides relevant information about the pathophysiological mechanisms whereby both caterpillars can induce toxicity on human beings, and paves the way for novel discovery of naturally occurring bioactive compounds.
ABSTRACT
Megalopygids Megalopyge lanata and Podalia orsilochus are common causative agents of accidents in agricultural workers. These accidents are provoked by dermal contact at their larval stage and are characterized by cutaneous reactions, such as burning pain, edema and erythema, typically mild and self-limited. There is very little information about their venoms and their toxicological implications on human health. Thus, we employed proteomic techniques and biological assays to characterize venoms (bristle extracts) from caterpillars of both species collected from Misiones, Argentina. The electrophoretic profiles of both venoms were substantially different, and they presented proteins related to toxicity, such as serinepeptidases, serpins and lectins. P. orsilochus venom exhibited higher caseinolytic activity than M. lanata venom, agreeing with the fact that only P. orsilochus venom hydrolyzed human fibrin(ogen). In addition, the latter shortened the clotting time triggered by calcium. While the venom of M. lanata induced a mild inflammatory lesion in mouse skin, P. orsilochus venom caused prominent necrosis, inflammatory infiltration and hemorrhage at the site of venom injection. On the other hand, P. orsilochus venom was better recognized by Lonomia obliqua antivenom, although many of its proteins could not be cross-reacted, what may explain the difference in the clinical manifestations between accidents by Podalia and those by Lonomia. Altogether, this study provides relevant information about the pathophysiological mechanisms whereby both caterpillars can induce toxicity on human beings, and paves the way for novel discovery of naturally occurring bioactive compounds.
ABSTRACT
Dermal contact with Lepidoptera specimens at their larval stage (caterpillar) may cause systemic and/or local envenomation. There are multiple venomous species of them in Argentina, but their overall venom composition is poorly known. Lately, several cases of envenomation have been reported in the Misiones province, Northeastern Argentina. Thus, this work aimed to compare the protein composition, and the enzymatic properties of bristle extracts from caterpillars belonging to the families Megalopygidae (Podalia ca. fuscescens) and Saturniidae (Leucanella memusae and Lonomia obliqua) - the most common causative agents of accidents in Misiones -, and additionally to test their cross-reactivity with the L. obliqua antivenom produced in Brazil. Saturniidae venoms exhibited striking similarity in both their electrophoretic protein profile, and antigenic cross-reactivity. All venoms degraded azocasein - with the highest proteolytic activity observed in the P. ca. fuscescens bristle extract -, and hyaluronic acid, but the latter at low levels. Lonomia obliqua venom exhibited the highest level of phospholipase A2 activity. Bristle extracts from P. ca. fuscescens and L. obliqua both degraded human fibrin(ogen) and shortened the clotting time triggered by calcium, while L. memusae venom inhibited plasma coagulation. Proteins related to the coagulation disturbance were identified by mass spectrometry in all samples. Altogether, our findings show for the first time a comparative biotoxinological analysis of three genera of caterpillars with medical relevance. Moreover, this study provides relevant information about the pathophysiological mechanisms whereby these caterpillar bristle extracts can induce toxicity on human beings, and gives insight into future directions for research on them.
