Tetrahymena is an oligohymenophoran ciliate and a very common
freshwater ciliate. It is usually used to demonstrate the levels of organization and
cortical features that are characteristic of the ciliate taxa.
The pictures below are of a silver nitrate-stained specimen of Tetrahymena.
The cilia themselves do not stain, but their location can
be identified because the region between the cilium and the kinetosome takes up silver
ions. Collectively, all the stained kinetosomes in a row represent a kinety
although the other structures in a kinety have not stained. The kineties of the somatic
region of the cell constitute the kinetome and the polykineties of the oral area
constitute the oral apparatus.
After the first ciliate lab, you may already have an understanding of
the following structures below that you need to identify and label clearly in your
drawings. Make sure you have a ventral view and a lateral view of Tetrahymena.
Include the following structures and morphology:
(Insert slides with labels of each structure)
These will be stained by the silver nitrate and will
appear as little brown dots on the surface of Tetrahymena.
|These will appear as parallel lines of dots (basal bodies) running down
the length of the cell surface.|
|Primary and Secondary Meridians (alveolar boundaries)|
|The primary meridian is a line of kineties with basal bodies while the
secondary meridian is the next meridian over with no kineties.|
|The oral apparatus is located on the anterior end of the cell and can be
easily seen as a small cavity in the ventral view of the cell. |
|Nothing unusual. You have seen other buccal cavities by now and can
easily identify this structure in Tetrahymena.|
Again nothing is surprising about this opening in Tetrahymena.
|Located on the right hand side of the buccal overture. There are three
regions of polykineties: P1, P2, and P3 and these can be found in the buccal cavity and
are quite distinct. You may have to focus up and down to see all three regions of
|Located on the left hand side of the buccal overture. There is only one
region of haplokinety and appears as a curved line in the ventral view of Tetrahymena.|
|This structure can be seen at the posterior end of the organism in the
dorsal view. It appears as a small darkly stained hole on the right side of the organism. |
These are a drawings demonstrating ventral and dorsal view of Tetrahymena
vorax and Tetrahymena pyriformis under the light microscope with the 100x lens.
Try to focus in at the buccal cavity and find all three regions of polykineties. As well,
focus on the alveolar boundaries and label primary and secondary meridians clearly, noting
their patterns and presence or absence of basal bodies.
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