Ultrastructural and cytochemical characterization of T1 and T2 secretory bodies from the tegument of Echinostoma paraensei

Trematodes are lined by a syncytial layer that is named the tegument and contains small mitochondria and two different kinds of secretory inclusions. The structure and size of these bodies differs among genera and species. In a previous study, we observed many secretory bodies in the tegument of Echinostoma paraensei and named these bodies the T1 and T2 secretory bodies. No previous studies analyzed the secretory bodies of trematodes from the genus Echinostoma. Thus, the aim of this work was to use electron microscopy and cytochemistry to characterize these secretory bodies and to provide a detailed ultrastructural and morphological picture of these bodies, which are found in the tegument of E. paraensei. After ultrastructural cytochemistry analysis, we showed that both the T1 and T2 secretory bodies of E. paraensei were formed by glycoconjugates. 3D reconstruction confirmed the ovoid form of T1 secretory bodies and the biconcave and thin form of T2 secretory bodies.