Mitochondrial and cytoplasmic ribosomes from Tetrahymena pyriformis have been isolated and studied by the techniques of polyacrylamide gel electrophoresis and electron microscopy used in conjunction. Although the two ribosome types show the same coefficient of sedimentation (80S) in sucrose gradients, they can be distinguished by gel electrophoresis: mitoribosomes migrate in a single band, considerably slower than the cytoribosome band. Electron microscope observations of negatively stained cytoribosomes show typical rounded or triangular profiles, about 275 x 230 Å; mitoribosome profiles are much larger and clearly elongate, about 370 x 240 Å. An electron-opaque spot delimits two nearly equal size subunits. In mixtures of mito- and cytoribosomes, each type can be recognized by its characteristic electrophoretic mobility and by its distinctive fine structure. Cytoribosomal 60S and 40S subunits each produce a distinct electrophoretic band. On the contrary, neither electrophoretic analysis, using a variety of conditions, nor electron microscopy is able to discern two different subunit types in the single 55S mitoribosomal subunit peak. Electrophoretic analysis of RNA shows that both ribosomal RNA species are present in the mitoribosomal subunit fraction. These results establish that mitoribosomes from T. pyriformis dissociate into two subunits endowed with the same sedimentation coefficient, the same electrophoretic mobility, and a similar morphology.
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1 March 1974
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March 01 1974
MITOCHONDRIAL AND CYTOPLASMIC RIBOSOMES FROM TETRAHYMENA PYRIFORMIS : Correlative Analysis by Gel Electrophoresis and Electron Microscopy
Jean-Jacques Curgy,
Jean-Jacques Curgy
From the Laboratoire de Biologie Cellulaire 4, Université de Paris XI, 91405 Orsay, France.
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Gérard Ledoigt,
Gérard Ledoigt
From the Laboratoire de Biologie Cellulaire 4, Université de Paris XI, 91405 Orsay, France.
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Barbara J. Stevens,
Barbara J. Stevens
From the Laboratoire de Biologie Cellulaire 4, Université de Paris XI, 91405 Orsay, France.
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Jean André
Jean André
From the Laboratoire de Biologie Cellulaire 4, Université de Paris XI, 91405 Orsay, France.
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Jean-Jacques Curgy
From the Laboratoire de Biologie Cellulaire 4, Université de Paris XI, 91405 Orsay, France.
Gérard Ledoigt
From the Laboratoire de Biologie Cellulaire 4, Université de Paris XI, 91405 Orsay, France.
Barbara J. Stevens
From the Laboratoire de Biologie Cellulaire 4, Université de Paris XI, 91405 Orsay, France.
Jean André
From the Laboratoire de Biologie Cellulaire 4, Université de Paris XI, 91405 Orsay, France.
Dr. Ledoigt's present address is Laboratoire de Cytophysiologie de la Photosynthèse, 91190 Gif-sur-Yvette, France
Received:
May 11 1973
Revision Received:
October 17 1973
Online ISSN: 1540-8140
Print ISSN: 0021-9525
Copyright © 1974 by The Rockefeller University Press
1974
J Cell Biol (1974) 60 (3): 628–640.
Article history
Received:
May 11 1973
Revision Received:
October 17 1973
Citation
Jean-Jacques Curgy, Gérard Ledoigt, Barbara J. Stevens, Jean André; MITOCHONDRIAL AND CYTOPLASMIC RIBOSOMES FROM TETRAHYMENA PYRIFORMIS : Correlative Analysis by Gel Electrophoresis and Electron Microscopy . J Cell Biol 1 March 1974; 60 (3): 628–640. doi: https://doi.org/10.1083/jcb.60.3.628
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