Ultrastructural observations on the etiologic agent of cutaneous leishmanasis in south western Saudi Arabia

ABSTRACT

The ultrastructure of three isolates of the promastigote stage of the etiologic agent of cutaneous leishmaniasis in South Western Saudi Arabia is described. The Utrastructural features of all isolates are similar and are compared with other described leishmaniasis. A hypothetical diagrammatic drawing of the promastigote stage was compiled from a number of electron micrographs. The periplast of the cell is formed of a thin smooth plasma membrane which lacks any substantial coating. A single layer of subpellicular microtubules is seen in a ribosome free area. Subpellicular microtubules show a striated appearance in longitudinal sections. The number of these microtubules in the three isolates seems to be significant to the plane of transverse sections; being the largest in the nuclear leveled sections. The number also differs in each of the three isolates and differs from those recorded in other species. The arrangement of these microtubules seems to be in a helical pattern Subpellicular microtubules are not seen the area of the flagellar pocket; instead there is a group of 3-4 flagellum associated microtubules parallel to the flagellar pocket. These microtubules are associated with desmosomes. The ultrastructure of the promastigote is affected to some extent according to the phase of the cell in the culture. Some peculiarities may occur in long sustained promastigote cultures of leishmaniasis