Yvonne Raven

Date of Award


Degree Type


University or Center

Atlanta University (AU)


School of Arts and Sciences

Degree Name





By means of electron microscopy, a study has been made of the fine structure of the second-generation merozoites of Eimeria tenella obtained in scrapings of epithelial cells from the caecum of white leghorn cockerels. These specimens were fixed in osmium tetroxide and osmium permanganate, embedded in Epon 812, sectioned with a diamond knife, mounted on uncoated 300-mesh grids and examined in a Philips EM lOO-C microscope.

This study revealed numerous points of similarity to Toxoplasma, Sarcocystis, Plasmodium, Lankesterella, Eimeria intestinalis and Eimeria bovis.

The merozoite was fusiform-shaped and enclosed in a cell membrane. Some structural views revealed a discontinuity of the membrane made by a micropyle in the vicinity of the nucleus. Golgi apparatus lay near the nucleus. The polar ring anterior was situated in a cone-like body called the apical cone.. Paired organelles and convoluted tubules were also visible. Numerous mitochondria were scattered in many views of the parasite. Dense and semi-dense membrane enclosed bodies, possibly protein, were occasionally found near the mitochondria. Cross section of the mitochondria revealed tubular cristae situated in a dense matrix. Numerous free ribosomes and ribosomes attached to rough-surfaced endoplasmic reticulum surrounded these sections.

Included in

Biology Commons