Excretory system ultrastructure of diphyllobothriid tapeworm Pyramicocephalus phocarum (Cestoda) with cytochemical and functional implicationстатьяИсследовательская статья
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Аннотация:The article describes the architecture and ultrastructure of the excretorysystem (protonephridial system) of the plerocercoid Pyramicocephalus phocarum(Fabricius, 1780), a parasite of the liver of the cod Gadus morhua Linneaus, 1758. Theexcretory system consists of cyrtocytes and a syncytial excretory epithelium, which formsthe protonephridial funnels, the canal system, and the excretory bladder. Our immunocytochemicalstudies have shown that cyrtocytes are immunoreactive to α-tubulin, theprotonephridial complexes are reactive to fibrillar actin. The excretory epithelium consistsof differentiated apical cytoplasm specializing at secretion and reabsorption, and submergedcytons/perikarya. Architecture of the excretory system includes syncytial canals ofvarious diameters and positions within the body. The 1st and the 2nd order canals form acomplex three-dimensional peripheral network. The longitudinal central (main) excretorycanals branch dichotomously at the posterior end of the body and flow into the excretorybladder. The main excretory canals possess a thick muscular wall innervated by the centralnervous system. In addition, the ultrastructure of the excretory bladder, nephropore,terminal excretory pore are described. A close connection between the excretory andnervous systems occurs in the plerocercoid body. In the scolex, the main excretory canalsand transverse excretory anastomoses pierce the brain, and underlie the transverse cerebralcommissure. Neurites of the main nerve cords innervate the main excretory channels. Apartfrom this, there are unciliated sensory organs in the wall of the terminal excretory pore. Thefunctional significance of the described structures is discussed. Based on the obtainedultrastructural and immunocytochemical data, we support the hypothesis of primaryultrafiltration through a molecular sieve of the glycocalyx, covering the weir ribs ofprotonephridia.