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Ultrastructure of Trypanosoma cruzi in the rectum of Rhodnius prolixus

1966; Elsevier BV; Volume: 19; Issue: 3 Linguagem: Inglês

10.1016/0014-4894(66)90078-6

1090-2449

Antonio Sanabria,

Research on Leishmaniasis Studies

The rectal ampulla of Rhodnius prolixus was dissected 1, 3, 5, 10, 13, 20 and 25 days after the last feeding from white mice infected with Trypanosoma cruzi. The fine structure of the parasite from the invertebrate host was studied with the electronmicroscope. Two parasitic forms were described: the crithidia and the trypanosome. The crithidial form is limited by a cellular membrane underneath which are the striae of the periplast; its cytoplasm has a central, oval nucleus. The kinetonucleus is near the nucleus, their walls, at times, coming into close contact. The cytoplasm has a well-developed mitochondrial apparatus, as well as numerous ribosomes, isolated or in rosettes that are associated with the rough-surfaced endoplasmic reticulum. Spheroid bodies, containing osmiophilic masses, were also observed in the cytoplasm. In the concavity of the kinetonucleus lies the basal corpuscle. It is associated with the flagellum, which emerges from an invagination of the parasite's membrane, the so-called reservoir. The transformation of the crithidia into the metacyclic trypanosome seems to take place progressively by the shifting of the kinetonucleus to the posterior end of the parasite, the kinetonucleus then becomes the posterior vacuole. There is also a great development of the flagellum and the undulating membrane. The most characteristic feature of the parasitic forms living in the rectum of the triatomid is the abundance of mitochondria, which may stem from the kinetonucleus. The great development of the chondrioma in this form, in contrast to the few mitochondria observed in the intramyocardial parasite, might possibly depend on the change of nutrients in the medium.