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

CIL:12344*  Cite 

P. multimicronucleatum in defecation. When a spent vacuole has fused with the single membrane along the midline of the ridge the lips of the cytoproct split apart and form a wide gap. The membrane of the spent vacuole is now continuous with the plasma membrane and quickly undergoes vesiculation into vesicles that are released back into the cytosol. No membrane is released into the surrounding environment. The cytoproct lips are covered by extensions of alveoli up to their tips. Complete defecation is insured by the retrieval of all of the spent vacuole membrane until the lips are pulled back together at the tip of the ridge and all DV-IV membrane has been removed from the cytoproct. No other expulsion force is needed for expelling the vacuole contents. TEM taken on 5/25/82 by R. Allen with Hitachi HU11A operating at 60kV. Neg. 6,500X.

Technical Details

The raw film was scanned with an Epson Perfection V750 Pro. This image is best used 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
cortical cytoskeleton 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
unprocessed raw data
Data Qualifiers
raw, unprocessed data
suitable for spatial measurements
Spatial Axis Image Size Pixel Size
X 4970px 2nm
Y 6142px 2nm