The in vitro uptake and distribution of super(3)H-fucose and super(2)H-mannose in the crayfish retina: A light and electron microscope autoradiographic study

The in vitro uptake and distribution of super(3)H-fucose and super(3)H-mannose in the crayfish (Astacus)) retina was studied using light and electron microscope autoradiography. Animals maintained on a 12:12 light-dark (L-D) cycle were incubated for 8 hr in the light beginning at their normal light-onset time. Both sugars were incorporated into components of the rhabdom microvillous membrane. The pattern of labeling seen in the crayfish photoreceptor with these two sugars is similar to that reported in the vertebrate photoreceptor. The progressive labeling of the rhabdom during the time when membrane loss is also taking place suggests that both aspects of the renewal process in the crayfish occur simulataneously during the period of the light cycle examined.