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

CIL:36657*  Cite 

During self conjugation two cells from a 6-day old culture come together, bridges are formed between them and haploid products of meiotic division of their micronuclei are exchanged between the mating pairs. Two micronuclei are seen here which appear similar to the haploid pronucleus in the paper of Inaba et al. (Proc. Japan Acad. 42:394-398, 1966) which is passing through such a bridge in P. multimicronucleatum. In this micrograph two rounded micronuclei are lying very near the macronucleus. These may be the migratory and stationary pronuclei that will form the diploid synkaryon nucleus from which the new micronuclei and macronucleus will form after further mitotic divisions. Interestingly one of these nuclei appears to be in close contact with the macronucleus. TEM taken on 3/4/80 by R. Allen with Hitachi HU11A operating at 75kV. Neg. 5,000X. Bar = 1µm.

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. The negative was printed to paper and the image was scanned to Photoshop. This digitized image is available for qualitative analysis. Additional information available at (

Biological Sources
NCBI Organism Classification
Paramecium multimicronucleatum
Cell Type
cell by organism
eukaryotic cell
Eukaryotic Protist
Ciliated Protist
Cellular Component
Richard Allen (University of Hawaii)
Digital Object Identifier (DOI)
Archival Resource Key (ARK)
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
uranyl salt
lead salt
osmium tetroxide
Processing History
recorded image
Print from negative scanned for Photoshop.
Data Qualifiers
processed data
Spatial Axis Image Size Pixel Size
X 2630px ——
Y 3000px ——