Carbohydrate/lectin interactions between the nematophagous fungus,Arthrobotrys oligospora, and the infective juveniles ofTrichostrongylus colubriformis(Nematoda)

Abstract

Removal of the sheath of the ensheathed infective juvenile of Trichostrongylus colubriformis prevents capture by the nematophagous fungus Arthrobotrys oligospora. Exposure of the trap hyphae to a variety of saccharides, which may block a recognition system based on lectin/carbohydrate binding, failed to prevent capture but some saccharides did inhibit penetration and invasion by the fungus. Capture and penetration thus appear to be two distinct processes with capture being less specific than penetration. Carbohydrate residues were absent from the outer surface of the cuticle and the sheath but were present on the inner surface of the sheath. The limited accessibility of these lectin-binding sites may explain the slow process of infection of the infective juvenile by the fungus. The sheath does not protect the infective juvenile against attack by this nematophagous fungus.

Controle biológico de helmintos parasitos de animais: estágio atual e perspectivas futuras

“…A segunda cutícula das larvas infectantes (L 3 ) dos nematóides parasitos de animais domésticos, parece não proteger as larvas da predação pelos fungos, pois os mesmos são menos hábeis em predar L 3 sem cutícula externa (Wharton & Murray 1990). Em experimentos mais recentes, entretanto, se verificou que isolados de Arthrobotrys spp tiveram maior capacidade predatória sobre larvas infectantes sem cutícula externa, demonstrando que há uma complexa relação entre receptores de superfície dos nematóides e ligantes presentes na parede celular dos fungos (Araújo 1998).…”