Electron Microscopic Study of Trypanosoma cruzi Periplast in Tissue Cultures. I. Number and Arrangement of the Peripheral Microtubules in the Various Forms of the Parasite's Life Cycle*

Abstract

In an EM study counts of peripheral microtubules were made in spheromastigotes and trypomastigotes in tissue cultures of [chick] embryonic heart muscle cells. In interphase spheromastigotes there were at the level of the nucleus, .apprx. 114 microtubules; in dividing forms, there were .apprx. 222. In trypomastigotes the number of microtubules varied according to the level of the section-there were < 40 tubules in the pointed ends of an organism, while in the central segment the number of these elements ranged from 60-115. The highest number of microtubules was in the region containing the Golgi complex. The distance between the microtubules was a constant 44 nm, even at the pointed ends of a trypanosome. This suggests that the microtubules course parallel to one another. Cross sections and randomly arranged, variable length longitudinal sections of the tubules were noted around the kinetosomes in dividing organisms.