The cytoproct is the site of spent vacuole defecation on the surface of Paramecium. When closed the cytoproct forms a long narrow wavy ridge along the posterior suture. At its apex the ridge is about 0.2?m wide and it can be as much as 12?m or more in length. This ridge has the ability to be pulled down against the approaching spent vacuole where the plasma membrane covering the midline of the ridge will meet and fuse with the membrane of the vacuole. The ridge contains unique fibers on both of its lips that mesh with each other as they meet inside the ridge (see Allen and Wolf, J. Cell Sci. 14:611-631, 1974). TEM taken on 4/19/79 by R. Allen with Hitachi HU11A operating at 60kV. Neg. 10,000X. Bar = 0.5?m. The negative was printed to paper and the image was scanned to Photoshop. This digitized image is available for qualitative analysis. An unprocessed, high resolution version of this image (CIL:12343) is in the library and available for quantitative analysis. 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 (http://www5.pbrc.hawaii.edu/allen/).
Biological Process: Cortical cytoskeleton organization
Author: Richard Allen (University of Hawaii)
Source: The Cell: An Image Library