Characterization of the lipid transfer to enterocytes in Panstrongylus megistus (Hemiptera: Reduviidae)

FRUTTERO, LL; STARIOLO, R; RUBIOLO, ER; CANAVOSO, LE

BIOCELL

Inca Editorial

Lugar: Mendoza, Argentina; Año: 2008 vol. 32 p. 111 - 111

0327-9545

In insects, the transfer of hemolymph lipids to tissues is a remarkable event accomplished by lipophorin (Lp), the major insect lipoprotein. This process allows the formation of essential lipid reserves, which in turn will be used in many physiological events. In this work, we have analized the mechanisms involved in the transfer of lipids from Lp to the midgut of P. megistus, an important vector of Chagas´ disease. Lp was isolated from hemolymph of the fifth instar nymphs by a KBr gradient. The enterocyte membranes were obtained by ultracentrifugation of midgut homogenates. Lp interaction with midgut membranes was characterized by solid-phase binding assays. Lp binding sites in enterocytes were localized by direct immunofluorescence. Lp-binding proteins at the membranes were studied by ligand blotting assays and visualized by western blotting. Results showed: [a] a clear dependence of the Lp binding to membranes with the pH. Lp binding also showed a kinetic of saturation compatible with a model for a single binding site, [b] the interaction of Lp with midgut cells mainly occur at their basolateral region, wich in vivo contacts with hemolymph; [c] at the membrane, Lp mainly interacted with a protein of 71 KDa. Taking together, these results increase our understanding about the metabolics pathways of lipids in insects as well as the physiological processes ocurring in these vectors of Chagas´ disease.