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

CIL:36717*  Cite 

In some cells exposed to horseradish peroxidase (HRP) for 30 sec and then immediately fixed some HRP has already entered the cell by endocytosis and has been removed from the early endosomes in carrier vesicles. In this picture such carrier vesicles have already docked at acidosomes that are themselves docked at a nascent digestive vacuole. Carrier vesicles will fuse with the acidosomes to add their content and membrane to the acidosomes. This is why two populations of acidosomes are often seen around the nascent phagosome and early DV-I, acidosomes that contain HRP because they have fused with HRP-containing carrier vesicles and those that have not fused with HRP-containing carrier vesicles. (See Allen, Ma and Fok, J. Cell Sci. 106:411-422, 1993). TEM taken on 2/24/82 by R. Allen with Hitachi HU11A operating at 75kV. Neg. 21,250X. Bar = 0.2µm.

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
endocytic vesicle lumen
vesicle membrane
early endosome
Biological Context
Biological Process
digestive system process
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
osmium tetroxide
uranyl salt
lead salt
Processing History
recorded image
Print from negative scanned for Photoshop.
Data Qualifiers
processed data
Spatial Axis Image Size Pixel Size
X 2087px ——
Y 2400px ——