Fine structure of leishmania in dermal leishmanoid

Abstract

Electron micrography morphology of the Leishman-Donovan body occurring in a nodular lesion of dermal leishmanoid has been described. The size is similar to that of L. donovani as demonstrated by light microscopy. The leishmania shows a double-layered pellicle with a clear zone in between. A layer of subpellicular hollow fibrils numbering 80-120 is present. The nucleus has a double membrane with electron-dense material about 0.1 [mu] thick on its inner aspect, and a karyosome. The distribution of this material corresponds to that of DNA as determined by the Feulgen reaction. The kinetoplast is seen as a series of electron-dense fibrils in a dilated area of a large mitochondrion; the fibrils correspond to the localization of Feulgen-positive kinetoplast in light microscopy. The rhizoplast is a complex structure with the usual 9 + 1 set of fibrils. It invaginates through a sac-like structure, the wall of which covers the fibrils and lines the vacuole around the fibrils. A funnel-shaped invagination of the pellicle extends to the neck of the rhizoplast, the distal end of which passes on to the surface of the parasite through the pit formed by the pellicular invagination. Other cytoplasmic structures have been described, viz., the Golgi apparatus, the endoplasmic reticulum, the ribosomes, etc. The possible functional, cytochemical and morphogenetic implications of the structural pattern have been considered.