Morphogenesis of the flagellum and its associated structures in Leishmania.

Electron microscopic study of the flagellar apparatus of promastigote and amastigote forms of Leishmania revealed major differences. Promastigotes were characterized by possessing a paraxial rod with a well developed lattice-like complex alongside the emerging axoneme enclosed within the flagellar sheath. The latter was anchored to the protozoan plasma membrane by focal or spot-like macular desmosomes at the emergence site. With cytodifferentiation to amastigotes there was a notable reduction in the axonemal size and its microtubular elements, absence of paraxial rod and a remarkable binding of the endocellular flagellum to its pocket through dense zonular desmosomal adhesions.