Oocyst wall formation and composition in coccidian parasites

Memórias do Instituto Oswaldo Cruz

Kelly Mai¹  Philippa A Sharman¹  Robert A Walker¹  Marilyn Katrib¹  David De Souza¹  Malcolm J Mcconville¹  Michael G Wallach¹  Sabina I Belli¹  David Jp Ferguson¹  Nicholas C Smith¹ 

[1],University of Technology Institute for the Biotechnology of Infectious Diseases Sydney,Australia

关键词: Coccidia;    oocyst;    dityrosine crosslinking;    Toxoplasma;    Eimeria;   

DOI  :  10.1590/S0074-02762009000200022

来源: SciELO

【 摘 要 】

The oocyst wall of coccidian parasites is a robust structure that is resistant to a variety of environmental and chemical insults. This resilience allows oocysts to survive for long periods, facilitating transmission from host to host. The wall is bilayered and is formed by the sequential release of the contents of two specialized organelles - wall forming body 1 and wall forming body 2 - found in the macrogametocyte stage of Coccidia. The oocyst wall is over 90% protein but few of these proteins have been studied. One group is cysteine-rich and may be presumed to crosslink via disulphide bridges, though this is yet to be investigated. Another group of wall proteins is rich in tyrosine. These proteins, which range in size from 8-31 kDa, are derived from larger precursors of 56 and 82 kDa found in the wall forming bodies. Proteases may catalyze processing of the precursors into tyrosine-rich peptides, which are then oxidatively crosslinked in a reaction catalyzed by peroxidases. In support of this hypothesis, the oocyst wall has high levels of dityrosine bonds. These dityrosine crosslinked proteins may provide a structural matrix for assembly of the oocyst wall and contribute to its resilience.

【 授权许可】

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