An electron microscope study of the cortex of Paramecium caudatum has revealed new details pertinent to several unresolved problems. The lateral boundaries of the alveoli do not regularly follow the crests of the polygonal ridges and thus their staining with silver cannot account for the external lattice seen by light microscopists. A granulo-fibrillar material is present, however, within the peaks of the ridges, which would account for the external lattice if so stained. Perforations are present between adjacent alveoli which make the whole mosaic of alveolar sacs within the cell's cortex continuous—both the membranes and the lumen. A microfibrillar system exhibiting a cross-striated pattern lies in the superficial cortex. These bands are inserted at their ends in the epiplasm and have a fine structure and arrangement suggesting a muscular function. The infraciliary lattice is a branching system of fibers with electron-opaque posts at the center of each branching locus. This system is distinct from the striated bands in morphology and in space. The epiplasm is discontinuous along the crests of the ridges, which may account for the pellicles' disposition to tear along these lines. A three-dimensional drawing is presented to show the interrelationships between the above membranous and microfibrillar systems.
Article| April 01 1971
FINE STRUCTURE OF MEMBRANOUS AND MICROFIBRILLAR SYSTEMS IN THE CORTEX OF PARAMECIUM CAUDATUM
Richard D. Allen
From the Biological Laboratories, Harvard University, Cambridge, Massachusetts 02138.
Dr. Allen's present address is the Pacific Biomedical Research Center, University of Hawaii, Honolulu, Hawaii 96822
Received: June 24 1970
Revision Received: September 07 1970
Online ISSN: 1540-8140
Print ISSN: 0021-9525
Copyright © 1971 by The Rockefeller University Press
Richard D. Allen; FINE STRUCTURE OF MEMBRANOUS AND MICROFIBRILLAR SYSTEMS IN THE CORTEX OF PARAMECIUM CAUDATUM . J Cell Biol 1 April 1971; 49 (1): 1–20. doi: https://doi.org/10.1083/jcb.49.1.1
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