title: Ultrastructure and cytochemistry of glycogen-containing vacuoles in gastrodermal cells in developing hydranths of a hydromedusan coelenterate.
abstract: Hydranth buds from the colonial hydroid Sertularia pumila (Hydromedusae) were observed by electron microscopy during their development. Before hydranth expansion, the gastrodermal columnar digestive cells had large numbers of vacuoles. These vacuoles contained many membranous components as well as alpha-glycogen and dense ring- and crescent-shaped bodies. The rings and crescents were not osmiophilic, but did react to periodic acid oxidation in the PA-TSC-SP test for carbohydrate. These structures were digestible by alpha-amylase and pullulanase. The chemical analyses and the close association of the rings and crescents to alpha-glycogen particles showed that they may be a highly condensed form of glycogen. Golgi bodies in association with the gastrodermal vacuoles had acid phosphatase activity. This enzyme was only slightly active in the vacuoles. It is suggested that the vacuoles are primarily storage organelles with a potential for digestion.
mesh_terms: D000818:Animals; D002451:Cell Compartmentation; D003063:Cnidaria / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure*; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D006003:Glycogen / Q000378:metabolism*; D008854:Microscopy, Electron
chemical_list: D006003:Glycogen