LIGHT AND ELECTRON-MICROSCOPY ON SPORULATION OF OOCYSTS OF EIMERIA-BRUNETTI .2. DEVELOPMENT INTO SPOROCYST AND FORMATION OF SPOROZOITE

  • 1 January 1978
    • journal article
    • research article
    • Vol. 86  (1) , 13-24
Abstract
The later stages of sporulation in oocysts of E. brunetti were examined in samples which had been allowed to sporulate at 27.degree. C for 24, 36 and 48 h. The sporoblasts became ellipsoidal and the nucleus underwent the final division. A nucleus with associated Golgi bodies was seen at either end of the organism. The cytoplasm was limited by 2 unit membranes and contained rough endoplasmic reticulum, dense bodies, electron translucent vacuoles and mitochondria. The 1st evidence of sporozoite formation was the appearance of a dense plaque at either end of the organism. This appeared in the vicinity of the nuclei, and adjacent to the limiting membrane of the sporoblast. At this stage the sporocyst wall was still unformed. Then the 2 sporozoites were formed from opposite ends of the organism by growth of the dense plaques and invaginations of the plasmalemma which formed the pellicles of the developing sporozoites. A conoid and subpellicular microtubules were observed at this stage and as development continued, a number of vacuoles were found between the nucleus and the conoid. These vacuoles constituted the precursors of the rhoptries and micronemes. At the same stage a large dense body had appeared within the forming sporozoite. As the sporozoite developed, this body, the anterior refractile body, is followed by the nucleus and another dense body which formed the posterior refractile body. During this period, the thin sporocyst wall was formed and Stieda and sub-Stieda bodies were present at one end of the sporocyst. Each mature sporocyst contained 2 sporozoites.