Alternate header for print version

Public Domain: This image is in the public domain and thus free of any copyright restrictions. However, as is the norm in scientific publishing and as a matter of courtesy, any user should credit the content provider for any public or private use of this image whenever possible. Learn more
*CIL – Cell Image Library accession number. Please use this to reference an image.

CIL:9927*  Cite 

A high resolution image of the pellicle of Didinium, in cross section of a non-dividing cell, has a plasma membrane with a distinct glycocalyx on its external surface and a flattened alveolar sac system. Under the alveoli are one or two or more ribbons of microtubules in ridges between the more corrugated mucocyst docking sites. Mitochondria with tubular cristae lie under the epiplasm in the ribosome filled cytosol. TEM taken on 2/18/69 by R. Allen with Philips 300 operating at 60kV. Neg. 20,500X. The raw film was scanned with a Nikon Coolscan 9000ED. 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
Didinium nasutum
Cell Type
cell by organism
eukaryotic cell
Eukaryotic Protist
Ciliated Protist
Cell Line
Carolina Biological Supply Company, NC, U.S.A.
Cellular Component
cell cortex
cortical microtubule cytoskeleton
Biological Context
Biological Process
cortical organization
cortical microtubule organization
membrane organization
Molecular Function
structural molecule activity
Richard Allen
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
Data Qualifiers
raw, unprocessed data
suitable for spatial measurements
Spatial Axis Image Size Pixel Size
X 4696px 1nm
Y 2958px 1nm