Electron microscopic study of Trypanosoma cruzi in thin sections of infected tissue cultures and of blood-agar forms

Abstract

Thin sections of Trypanosoma cruzi in tissue cultures and from blood agar medium have been examined with the electron microscope.In the leishmania and crithidia forms of the parasite a neat separation of kinetonucleus and blepharoplast has been obtained and these structures are described. The blepharoplast is the row of basal corpuscles which give origin to the axial fibres of the flagellum.Division of the parasite seems to begin in the basal corpuscles; it is followed by binary division of the kinetonucleus and only later by fission of nucleus and cytoplasm.During the development of the leishmania into the crithidia form, the kinetonucleus and basal bodies are dislocated towards the posterior half of the trypanosome. The migration of these two structures and the consequent lengthening of the flagellum causes the surface membrane of the flagellum to be pushed inwards to form a deep invagination, so that the flagellum comes to the surface of the body and is separated from it along its whole length by its own sheath.In the adult form of the parasite a great vacuole is formed near the posterior tip of the trypanosome. It has no definite structure in the electron microscope, is transparent and seems to be filled with a liquid content. The basal corpuscles are situated in this region near the wall of the vacuole. The typical structure of the kinetonucleus could not be identified with certainty in these forms; it seems to be altered by the formation of the vacuole.The vacuole is crossed by a fibre system which comes from the body of the trypanosome and is often dislodged by the size of the vacuole. This fibre system ends in a sharply pointed process of varying length.The cost of reproduction of figures was defrayed by the Instituto de Biofísica da Universidade do Brasil.

MITOCHONDRIA ASSOCIATED WITH THE KINETONUCLEUS OF TRYPANOSOMA MEGA

“…It is bounded by a double membrane and within it is a fibrillar material presumed to contain DNA (3). A more or less similar appearance has been observed in the kinetonuclei of T. equiperdum by Anderson et al (10) and of T. cruzi by Meyer et al (11). In favorable sections, it is seen that the kinetonucleus extends into structures with the typical features of mitochondria, including inner membranes or "cristae" (Figs.…”

“…limited knowledge of the ontogenesis of mitochondria. It is probable that future investigations will show the mitochondrial nature of unidentified bodies associated with the kinetonuclei of another trypanosome (11) and of a bodonid (15). The only mitochondrial-nucleus association approaching this in other cells is that described in the ameba, Chaos chaos, by Brandt and Pappas (16) who discuss it in terms of mitochondrial formation by the nucleus.…”

Structural organization of Trypanosoma cruzi

“…Early studies using electron microscopy (Meyer et al 1958) identified a dark, electron dense and slightly bent inclusion, corresponding to a structure known at that time as the kinetonucleus, which had been previously identified by light microscopy of stained cells. This structure is now known as the kinetoplast.…”

Pathogenesis of Chagas' Disease: Parasite Persistence and Autoimmunity

“…The remarkable molecular configuration of the kDNA network (279,326,360) continues directly into a typical mitochondrion canal system, as seen for any tissue cell (309). The kDNA is located within the mitochondrial matrix, and the position of the kinetoplast relative to the nucleus changes during the cell life cycle.…”