Crystalloid Body

This structure appears in electron microscopy as compact globules of several micrometers (μm) in diameter consisting of electron-dense particles arranged in a honeycomb-like pattern. The size of these particles varies depending on the species. In the hemogregarine Karyolysus, they measure 35–50 nm in diameter, in Cystoisospora only 30 nm, in Cryptosporidium they reach 16–35 nm, and in Plasmodium ookinetes and oocysts they measure about 43 nm and occur at several places (Figs. 2 and 3 in Kinetes). The functional role of the crystalloid bodies is still unknown, although they are discussed as reserve granules and/or as systems to regulate cryoprotection and intracellular osmolielity.