a1 The iThree Institute, School of Medical and Molecular Biosciences, University of Technology Sydney, PO Box 123, Broadway, Sydney, New South Wales, 2007, Australia
a2 Institute of Zoology, Technische Universität Dresden, Helmholtzstraße 10, 01062 Dresden, Germany
Eimeria maxima has been used as a model apicomplexan parasite to study sexual stage development and oocyst wall formation. A complete understanding of the wall's biochemical and biophysical properties is of great interest in research on all apicomplexan parasites. Purified gametocytes, zygotes and oocysts were analysed by three-dimensional confocal microscopy, and wide-field fluorescent microscopy was used to investigate the appearance and spatial organization of the 2 types of wall-forming bodies (WFBs). In addition, a variety of staining procedures and immunoassays were used to assess the biosynthesis, metabolic activity, intactness and molecular composition of the WFBs in situ. WFBs were extracted from gametocytes/zygotes and their composition was assessed by microscopy and SDS-PAGE analysis. It was concluded that isolated gametocytes are intact and metabolically active. Additionally, it was observed that the Type 1 WFBs are aligned at the periphery of the parasite and fuse together producing neutral lipid rich patches that appear to be inserted into the space between 2 parasite-specific membranes. Finally, it was shown that the WFBs extracted from purified gametocytes had the same shape, size and staining properties as those observed in situ, and contained the major glycoprotein antigens known to be present in these organelles.
(Received October 12 2012)
(Revised December 10 2012)
(Accepted December 13 2012)
(Online publication March 14 2013)
c1 Corresponding author: The iThree Institute, School of Medical and Molecular Biosciences, University of Technology Sydney, PO Box 123, Broadway, Sydney, New South Wales, 2007, Australia. Tel.: +61-2-9514-4082. Fax: +61-2-9514-4026. E-mail: Michael.Wallach@uts.edu.au