Navegando por Palavras-chave "kinetoplast"

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    Morphological events during the Trypanosoma cruzi cell cycle
    (Elsevier B.V., 2007-04-01) Elias, Maria Carolina; Cunha, Julia P. C. da; Faria, Flavio P. de; Mortara, Renato A.; Freymueller, Edna; Schenkman, Sergio; Universidade Federal de São Paulo (UNIFESP); Inst Butantan
    The replication and segregation of organelles producing two identical daughter cells must be precisely controlled during the cell cycle progression of eukaryotes. in kinetoplastid flagellated protozoa, this includes the duplication of the single mitochondrion containing a network of DNA, known as the kinetoplast, and a flagellum that grows from a cytoplasmic basal body through the flagellar pocket compartment before emerging from the cell. Here, we show the morphological events and the timing of these events during the cell cycle of the epimastigote form of Trypanosoma cruzi, the protozoan parasite that causes Chagas' disease. DNA staining, flagellum labeling, bromodeoxyuridine incorporation, and ultra-thin serial sections show that nuclear replication takes 10% of the whole cell cycle time. in the middle of the G2 stage, the new flagellum emerges from the flagellar pocket and grows unattached to the cell body. While the new flagellum is still short, the kinetoplast segregates and mitosis occurs. the new flagellum reaches its final size during cytokinesis when a new cell body is formed. These precisely coordinated cell cycle events conserve the epimastigote morphology with a single nucleus, a single kinetoplast, and a single flagellum status of the interphasic cell. (C) 2006 Elsevier GmbH. All rights reserved.
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    Three-Dimensional Reconstruction of Trypanosoma cruzi Epimastigotes and Organelle Distribution Along the Cell Division Cycle
    (Wiley-Blackwell, 2011-07-01) Ramos, Thiago Cesar Prata [UNIFESP]; Freymüller-Haapalainen, Edna [UNIFESP]; Schenkman, Sergio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Trypanosoma cruzi is the protozoan that causes Chagas disease. It divides in the insect vector gut or in the cytosol of an infected mammalian cell. T cruzi has one mitochondrion, one Golgi complex, one flagellum, and one cytostome. Here, we provide three-dimensional (3D) models of this protozoan based on images obtained from serial sections on electron microscopy at different stages of the cell cycle. Ultrathin serial sections were obtained from Epon (TM) embedded parasites, photographed in a transmission electron microscope, and 3D models were generated using Reconstruct and Blender 3D modeling softwares. the localization and distribution of organelles was evaluated and attributed to specific morphological patterns and deduced by distribution of specific markers by immunofluorescence analysis. the new features found in the 3D reconstructions are (1) the electron-dense chromatin is interconnected leaving an internal space for a centrally located nucleolus; (2) the kinetoplast is accommodated within a separated branch of the tubular and single mitochondrion; (3) the disk shaped kinetoplast, which is the mitochondrial DNA, duplicates from the interior in G2 phase; (4) the mitochondrion faces the external membrane and shrinks to accommodate an enlarged number of cytosolic vesicles from G1 to G2; (5) the cytostome progress from the parasite surface toward the posterior end contouring the kinetoplast and nucleus and retracts during cell cycle. These new observations might help understanding how organelles are formed and distributed in early divergent eukaryotic cells and provides a useful method to understand the organelle distribution in small eukaryotic cells. (C) 2011 International Society for Advancement of Cytometry