The coccidian oocyst: a tough nut to crack!

Belli, Sabina I.; Smith, Nicholas C.; Ferguson, David J. P.

doi:10.1016/j.pt.2006.07.004

Cited by 149 publications

(183 citation statements)

References 59 publications

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“…Facing the external environment, the oocyst wall acts as a primary barrier to physical and chemical attacks as long as its complex polymeric organization is perfectly maintained (8,12,26). Different, but complementary, approaches have been applied to investigate the structure and molecular basis of the oocyst wall resilience, such as EM (9,12,24,51) and proteomics studies (10,12).…”

Section: Discussionmentioning

confidence: 99%

“…In coccidian parasites such as T. gondii, the oocyst wall results from the particular arrangement of structural proteins through a sclerotization process involving both quinone tanning and protein dityrosine cross-linking and dehydration (12,26). This process probably takes place very early in the development of the oocyst wall, from the NS stage before it leaves the host (21), and is thought to lead to hardened structures, which excludes watersoluble molecules to form a complex polymeric covering capable of resisting extended physical and chemical-induced disorganization.…”

Section: Discussionmentioning

confidence: 99%

“…gondii oocysts are highly resistant to environmental influences; this resistance to various physical and chemical stressors, including disinfectants such as UV, ozone, and chlorine-based products, is attributed to the oocyst wall (4,25,26). In contrast, oocysts are rapidly inactivated following exposure to temperatures above 60°C for a few minutes (27).…”

mentioning

confidence: 99%

“…How these different proteins are processed and/or packed to form the oocyst wall is still not clear (8). Current models support a strong contribution of protein-tyrosine cross-linking in the formation and hardening of the oocyst wall in Toxoplasma-related coccidia (8,12,26,28) and results in the development of its typical blue autofluorescence (AF) under UV excitation (10,26,28,29) (SI Appendix, Fig. S1B).…”

mentioning

confidence: 99%

“…S1B). This complex polymeric organization also suggests an important robustness of the T. gondii oocyst wall in terms of mechanics (8,26). Thus, measuring mechanical properties of the T. gondii oocyst wall appears to be relevant to addressing the respective roles of structure and chemistry of each layer of the oocyst wall in the overall resistance of the oocyst to various physical and chemical agents (8).…”

mentioning

confidence: 99%

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Mechanics of the Toxoplasma gondii oocyst wall

Dumètre

Dubey

Ferguson

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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The ability of microorganisms to survive under extreme conditions is closely related to the physicochemical properties of their wall. In the ubiquitous protozoan parasite Toxoplasma gondii, the oocyst stage possesses a bilayered wall that protects the dormant but potentially infective parasites from harsh environmental conditions until their ingestion by the host. None of the common disinfectants are effective in killing the parasite because the oocyst wall acts as a primary barrier to physical and chemical attacks. Here, we address the structure and chemistry of the wall of the T. gondii oocyst by combining wall surface treatments, fluorescence imaging, EM, and measurements of its mechanical characteristics by using atomic force microscopy. Elasticity and indentation measurements indicated that the oocyst wall resembles common plastic materials, based on the Young moduli, E, evaluated by atomic force microscopy. Our study demonstrates that the inner layer is as robust as the bilayered wall itself. Besides wall mechanics, our results suggest important differences regarding the nonspecific adhesive properties of each layer. All together, these findings suggest a key biological role for the oocyst wall mechanics in maintaining the integrity of the T. gondii oocysts in the environment or after exposure to disinfectants, and therefore their potential infectivity to humans and animals.oocyst structure | oocyst integrity | oocyst resistance | Toxoplasma infectivity | transmission

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