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

CIL:34534*  Cite 

A high resolution micrograph. Most wild type Tetrahymena have a macronucleus and a micronucleus. The micronucleus, seen here, is essentially nonfunctional during interphase. Its function is to replicate and pass a complete copy of the genome to each daughter cell and to give rise to a new macronucleus following sexual reproduction. Many laboratory strains, unlike strain W which is shown here, have lost their micronucleus and seem to be able to live indefinitely without a micronucleus, however, they can no longer undergo meiosis and sexual reproduction. TEM taken on 4/8/65 by R. Allen with RCA EMU3F operating at 50kV. Neg. 9,100X. raw film was scanned with an Epson Perfection V750 Pro. This image is best used for quantitative analysis.

Technical Details

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
Tetrahymena pyriformis
Cell Type
cell by organism
eukaryotic cell
Eukaryotic Protist
Ciliated Protist
Cellular Component
autophagic vacuole
Biological Context
Biological Process
micronucleus 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 4974px 1.65nm
Y 6209px 1.65nm