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Electron Microscopy Analysis of the Nucleolus of Trypanosoma cruzi

Published online by Cambridge University Press:  07 July 2005

Gabriel López-Velázquez
Affiliation:
Department of Cell Biology, Faculty of Sciences, National Autonomous University of Mexico, México D.F., 04510, México Biochemistry and Genetics Laboratory, National Institute of Pediatrics, S.S., D.F., 04530, México
Roberto Hernández
Affiliation:
Department of Molecular Biology and Biotechnology, Biomedical Research Institute, National Autonomous University of Mexico, México D.F., 04510, México
Imelda López-Villaseñor
Affiliation:
Department of Molecular Biology and Biotechnology, Biomedical Research Institute, National Autonomous University of Mexico, México D.F., 04510, México
Horacio Reyes-Vivas
Affiliation:
Biochemistry and Genetics Laboratory, National Institute of Pediatrics, S.S., D.F., 04530, México
María de L. Segura-Valdez
Affiliation:
Department of Cell Biology, Faculty of Sciences, National Autonomous University of Mexico, México D.F., 04510, México
Luis F. Jiménez-García
Affiliation:
Department of Cell Biology, Faculty of Sciences, National Autonomous University of Mexico, México D.F., 04510, México
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Abstract

The nucleolus is the main site for synthesis and processing of ribosomal RNA in eukaryotes. In mammals, plants, and yeast the nucleolus has been extensively characterized by electron microscopy, but in the majority of the unicellular eukaryotes no such studies have been performed. Here we used ultrastructural cytochemical and immunocytochemical techniques as well as three-dimensional reconstruction to analyze the nucleolus of Trypanosoma cruzi, which is an early divergent eukaryote of medical importance. In T. cruzi epimastigotes the nucleolus is a spherical intranuclear ribonucleoprotein organelle localized in a relatively central position within the nucleus. Dense fibrillar and granular components but not fibrillar centers were observed. In addition, nuclear bodies resembling Cajal bodies were observed associated to the nucleolus in the surrounding nucleoplasm. Our results provide additional morphological data to better understand the synthesis and processing of the ribosomal RNA in kinetoplastids.

Type
BIOLOGICAL APPLICATIONS
Copyright
© 2005 Microscopy Society of America

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