The anterior esophageal region of Schistosoma japonicum is a secretory organ

Background: the esophagus of blood-feeding schistosomes has been largely neglected although its posterio portion was designated as a gland decades ago. however,we recently showed it plays a pivotal role in bloo processing. it is clearly demarcated into anterior and posterior compartments,both surrounded by a mass of cel bodies. feeding movies revealed that erythrocytes accumulate in the anterior compartment before entering th posterior,indicating that a distinct process is executed there. we therefore investigated ultrastructural aspects an possible functions of the anterior region methods: the heads of adult schistosoma japonicum were detached and prepared for both transmission an scanning electron microscopy to define the detailed ultrastructure of the anterior esophagus. cryosections of head were also prepared for immunocytochemistry and confocal microscopy to define the pattern of intrinsic hos antibody binding in the anterior esophageal lining results: the anterior syncytial lining of the esophagus is highly extended by long,thin corrugations of cytoplas projecting towards the lumen. strikingly in the male worm,the tips of the corrugations are further expanded b numerous threads of cytoplasm,producing a spaghetti-like appearance in the central lumen. flattened,pitte cytoplasmic plates are interspersed in the tangled mass of threads. abundant,morphologically distinct light vesicle of varied size and contents are manufactured in the cell bodies,from where they traffic through cytoplasmi connections to the corrugations and out to the tips. clusters of vesicles accumulate in expanded tips in males together with occasional mitochondria whilst females have more mitochondria but fewer vesicles. the membranou contents of light vesicles are secreted mainly from the tips,but also from the sides of the corrugations. they coa the surfaces and then form organised self-adherent membrane figures when shed into the lumen. host antibod binds strongly in a characteristic pattern to the anterior esophageal lining indicating that the secretions are highl immunogenic conclusions: we suggest that the anterior esophageal region is an independent secretory organ. the contents o light vesicles are released into the esophageal lumen via the tips of corrugation to interact with incoming blood our immediate task is to establish their composition and role in blood processing. © 2014 hong li et al..