Publication Date


Document Type


First Advisor

Zellen, Bruce von||Graves, Lynn B.||Norstog, Knut, 1921-

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences


Sporozoa; Rabbits


Sporozoites of Elmerla stiedae, an intracellular sporozoan undergoing schizogony and part of sporogony in rabbit bile duct epithelium were excysted in vitro and studied under the electron microscope. In vitro excystation was accomplished by incubation sporocysts in a PBS-trypsin solution containing 0.25% trypsin and 7 .0% ox bile. Incubation for one hour and forty-five minutes at room temperature resulted in 92% recovery of viable sporozoites. An electron microscope study of the sporozoite revealed that they are covered by a pellicle that terminates anteriorly in two apical rings. Beneath the apical rings are 25-27 microtubules. The anterior tip of the parasite has a conoid, paired organelle and branching toxonemes that run the length of the body and terminate around a dense posterior paranuclear body. Structures resembling parabasal bodies not previously reported in other sporozoan species were noted anterior to the nucleus. Numerous mitochondria, lipid inclusions and granules thought to be glycogen, surround the nucleus which is bound by a double membrane.


Includes bibliographical references.||Includes illustrations.


vi, 49 pages




Northern Illinois University

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