title: Autoradiographic and fine structural study of chitin deposition in the cuticle of a barnacle using [3H]-D-glucosamine incorporation.
abstract: [3H]-D-Glucosamine was injected into the rostral sinus of Balanus eburneus (barnacle) and the distribution of labelled chitin in the cuticle was studied with autoradiography and electron microscopy. When the pattern of labelling was examined in different body regions of the same organism where thickness of fully formed cuticle varied, it was observed that the rate of chitin deposition varied, being greater in thick than in thin regions. The density of Ag grains overlying cuticle was also greater in the thick regions. When the pattern of labelling was examined in regions of cuticle, comparable in thickness, taken from a series of organisms sacrificed at different time points a comparable value for the rate of chitin deposition was obtained. In addition, asynchrony in deposition of cuticle in different body regions of the same organism as well as uptake of the label by substances other than chitin, i.e. glycogen and glycoproteins were described.
mesh_terms: D000818:Animals; D001345:Autoradiography; D002686:Chitin / Q000378:metabolism*; D002688:Chitinases / Q000378:metabolism; D005944:Glucosamine / Q000378:metabolism*; D001468:Thoracica / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D002686:Chitin; D002688:Chitinases; D005944:Glucosamine