Interactive Multimedia to Teach the Life Cycle of Trypanosoma cruzi, the Causative Agent of Chagas Disease
Figure 5
General view depicting the stages of amastigote division by binary fission.
(A) In the preliminary phase of cell division, the nucleus displays condensed chromatin and a single nucleolus. (B) The early phase of the division process begins with the decondensation of chromatin and the disappearance of the nucleolus. (C) In the equatorial stage, there is early lateral growth of the kinetoplast and the appearance of a new basal body. This change is followed by the appearance of an arranged set of ten dense plaques in the equatorial region of the nucleus. These plaques are associated with an intranuclear spindle formed by microtubules. (D) The early elongational phase begins with the splitting of dense plaques, which migrate toward the nucleus poles. The nucleus elongates, and the spindle microtubules modify their distribution. The new flagellum emerges from the flagellar pocket. (E) In the final phase of elongation, the split dense plaques begin to migrate toward the nucleus poles, which exhibit an hourglass shape. This form represents the last stage of nucleus constriction. (F) In the reorganizative phase, the microtubules fade out in a stepwise fashion, the nucleolus begins to reconstitute, and the chromatin begins to condense. In this phase, the nuclei and kinetoplasts are already individualized. (G) At the stage of constriction, cytokinesis occurs and culminates with the formation of two independent amastigotes (H). These images were made based on micrographs of transmission electron microscopy.