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The Posttentacular Syncytia of Temnocephalids: the First Indication of a Putative Osmoregulatory Organ in the Epidermis of a Platyhelminth
Author(s) -
Joffe Boris,
Solovei Irina,
Can Lester R. G.
Publication year - 1996
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/j.1463-6395.1996.tb01268.x
Subject(s) - syncytium , biology , excretory system , epidermis (zoology) , osmoregulation , microbiology and biotechnology , anatomy , amphibian , septate junctions , cell , biochemistry , ecology , intracellular , salinity , gap junction
A small syncytium or a pair of syncytia is present in the dorsal epidermis of the four species studied ( Diceratocephala boschmai, Temnocephala dendyi, Craspedella sp., and Achenella sathonota ). Unlike the other epidermal syncytia, the posttentacular ones may be deeply stained with silver nitrate. The basal zone of the posttentacular syncytia is occupied by abundant deep invaginations of the basal cell membrane with densely packed mitochondria between them. In one species, A. sathonota , the nuclei containing portions of the posttentacular syncytia are insunk into the parenchyma. Ultrastructurally, the posttentacular syncytia are similar to the excretory bladder (the distal portion of the protonephridial canal) of the same animals and to osmoregulatory epithelial chloride cells known from many animals. These data suggest that ion transport in this syncytium serves for osmoregulation and maintenance of ion balance. Despite extensive studies of the epidermis, no hints of such cells have ever been reported in other platyhelminths. The accessory osmoregulatory organ is probably an adaptation to life in the gill chamber of the crustacean hosts which are characterized by high ability to maintain osmotic and ionic balance in stressful conditions.