Effects of Concanavaline-A on Leishmania Parasite Membrane Fluidity : a Fluorescence Study

The surface of Leishmania parasite promastigotes plays a vital role in their interactions with the host to bring about successful parasitism. The Leishmania macrophage binding is a membrane based phenomenon akin to ligand-receptor interaction in a broader sense. The promastigote surface protease, PSP or gp63, is thought to be involved in the binding to the macrophage. The enzyme also binds with concanavalin A (Con-A). We report here how the binding of Con-A with Leishmania membrane changes its anisotropy. The anisotropy is measured by using the fluorescent probe 1,6,diphenyl 1,3,5 hexatrene (DPH) as the reporter molecule. Our result shows that with increasing concentration of Con-A, the phase transition region broadens and the membrane anisotropy increases gradually.