High Resolution Low Voltage Field Emission Scanning Electron Microscopy on De-Embedded Thick Sections Reveals Structural Interactions of the Surface of the Apicomplexan Parasite Toxoplasma Gondii with the Host Cell in the Parasitophorous Vacuole

Abstract

The protozoan parasite Toxoplasma gondii represents a large group of Apicomplexan parasites with a highly unusual motility system that is crucial for cell locomotion and host cell invasion. Studying the motility system and interactions with host cells will increase our knowledge on how to prevent infection. Apicomplexan parasites can cause considerable health problems to animals including sheep, goats, pigs, and chicken. Eimeria is known as a pathogen of coccidiosis in chicken, and Cryptosporidium causes cryptospiridiosis in cattle and other farm animals. Toxoplasma gondii can cause infection that results in abortion, central nervous disorders and death of stressed and immunocompromised farm animals. Common to all Apicomplexan parasites is an unconventional motility system that is thought to be actively involved in host-cell invasion. However, the structural and biochemical characterization of Apicomplexan parasites has proven more difficult than previously thought because of genetic and behavioral differences of the parasites’ cytoskeletal proteins that differ from those in well studied mammalian systems.