High resolution image of Didinium (non-dividing) has a massive cytopharynx at its anterior end that takes the shape of a cone-shaped proboscis when closed. This cytopharynx contains numerous lamellae composed of sets of microtubules that lie perpendicular to each other next to the cytopharyngeal membrane. Vesicles containing a uniform medium dense material (mucocysts?), line up between the lamellae. Presumably these vesicles fuse with the single cytopharyngeal membrane that covers the lamellae. Extrusomes called toxicysts lie within in the cytopharyngeal region. TEM taken on 9/19/68 by R. Allen with Philips 300 operating at 60kV. Neg. 10,300X.
The raw film was scanned with a Nikon Coolscan 9000ED. The digitized image is 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/).
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