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

CIL:12977*  Cite 

The cortex of Paramecium consists of a plasma membrane and alveolar sacs, with their inner and outer alveolar membranes that limit the area in which endocytosis can easily occur to only the parasomal sacs. Parasomal sacs are cylindrical indentations of the plasma membrane that pass through the alveoli, not by penetrating through the sac but by passing through the septum. A short branch of the septum passes around the parasomal sac. In some areas the parasomal sacs extend almost perpendicularly from the basal bodies (not shown in this micrograph). There is one parasomal sac per surface depression in non-dividing cells. Rough ER, mitochondria, peroxisomes, trichocysts, and kinetodesmal fiber stack are seen in this image. The cell was incubated in hydrogen peroxide and diaminobenzidine to label the peroxisomes. TEM taken on 2/27/81 by R. Allen with Hitachi HU11A operating at 75kV. Neg. 10,250X. Bar = 0.5µm. 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:12610) 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
eukaryotic cell
Eukaryotic Protist
Ciliated Protist
Cellular Component
cell cortex
plasma membrane
internal side of plasma membrane
clathrin coat of coated pit
Biological Context
Biological Process
cortical organization
plasma membrane organization
clathrin coating of vesicles
peroxisome localization
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
Print from negative scanned for Photoshop.
Data Qualifiers
processed data
Spatial Axis Image Size Pixel Size
X 2382px ——
Y 2002px ——