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:36735*  Cite 

Cytochalasin B blocks DV release from cytopharynx. In this micrograph a very large nascent vacuole has been retained at the cytopharynx of this cell that had been exposed to cytochalasin B. Many acidosomes are docked at the membrane of this vacuole. Some acidosomes contain HRP reaction product and some are free of HRP. The cell had been exposed to HRP and cytochalasin B for 10 minutes during which no new DV-I had been released. During this exposure to CB, some discoidal vesicles continue to move to the cytopharynx and fuse, acidosomes continue to move to the nascent phagosome and dock, and endosome and carrier vesicle formation continues and they continue to fuse with acidosomes. CB has done two things, it has prevented normal phagosome release from the cytopharynx and it has also inhibited acidosome fusion with the phagosomes (Allen and Fok, J. Cell Biol. 97:566-570, 1983) once they form. For this study cells were exposed to 0.3mM of CB for 10-20 min. The lack of acidosome fusion with the few phagosomes that do pinch off during CB exposure was supported by the fact that the phagosomes became only mildly acid. TEM taken on 8/29/84 by R. Allen with Hitachi HU11A operating at 75kV. Neg. 1,610X. Bar = 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
food vacuole
Biological Context
Biological Process
response to drug
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 2287px ——
Y 3000px ——