Investigation of luminal surface structures of rod photoreceptor outer segments by lectin cytochemistry combined with freeze-etching.
The luminal surface of the rod photoreceptor disk membrane was exposed by means of osmotic shock and labeled with ferritin- conjugated concanavalin A. The structural changes of the luminal surface were examined by a freeze-etching procedure with cryoprotectant (methanol). On replicas from freeze-etched membranes with concanavalin A labeling, 6- to 10-nm particles were codistributed with ferritin particles on the luminal surface of the disk membrane. By contrast, there were few ferritin particles or less numerous 6- to 10-nm particles on the corresponding surface without concanavalin A labeling. If 6- to 10-nm particles corresponded to the carbohydrate moiety of rhodopsin, concanavalin A binding might tend to preserve this carbohydrate moiety. These results suggest that the two-dimensional analysis of lectin-induced structural changes of the membrane surface glycoconjugates may become available by lectin cytochemistry combined with freeze-etching.
D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D003208:Concanavalin A / Q000378:metabolism / Q000493:pharmacokinetics; D005293:Ferritins / Q000378:metabolism; D005613:Freeze Etching; D006651:Histocytochemistry; D007798:Lampreys; D008854:Microscopy, Electron; D010316:Particle Size; D012374:Rod Cell Outer Segment / Q000378:metabolism / Q000648:ultrastructure*