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*CIL – Cell Image Library accession number. Please use this to reference an image.

CIL:13134*  Cite 

The cytoproct ridge at higher magnification. The unique system of thick fibers extends from each side of the ridge toward the center of the ridge. These thickened fibers are not found in any other part of the cell’s surface. Also extending from the ridge tip are single microtubules that extend down into the cytosol. These microtubules may make contact with the surface of the approaching vacuole’s membrane and help to pull the vacuole membrane and the plasma membrane together to promote their fusion. The role of the thickened fibers is unclear, they may cross link to prevent the cytoproct from an untimely opening under stress. A few vesicles get trapped in the ridge. TEM taken on 6/1/84 by R. Allen with Zeiss 10A 80kV. Neg. 19,800X. Bar = 0.2µm. The negative was printed to paper and the image was scanned to Photoshop. This digitized image is available for qualitative analysis. An unprocessed, high resolution version of this image (CIL:12349) is in the library and available for quantitative analysis. Standard glutaraldehyde fixation followed by osmium tetroxide, dehydrated in alcohol and embedded in an epoxy resin. Microtome sections prepared at approximately 75nm thickness. Additional information available at (

Biological Sources
NCBI Organism Classification
Paramecium multimicronucleatum
Cell Type
cell by organism
eukaryotic cell
Eukaryotic Protist
Ciliated Protist
Cellular Component
cell cortex
Biological Context
Biological Process
cell cortex organization
cytoplasm organization
cytoproct organization
Richard Allen (University of Hawaii)
Digital Object Identifier (DOI)
Archival Resource Key (ARK)
Grouping This image is part of a group.
Image Type
transmission electron microscopy (TEM)
illumination by electrons
Image Mode
detection of electrons
Parameters Imaged
electron density
Source of Contrast
stain with broad specificity
Visualization Methods
stain with broad specificity
osmium tetroxide
uranyl salt
lead salt
Processing History
recorded image
Print from negative scanned for Photoshop.
Data Qualifiers
processed data
Spatial Axis Image Size Pixel Size
X 3072px ——
Y 3976px ——