Carotenoid replacement therapy in Drosophila: recovery of membrane, opsin and visual pigment

Rhabdomeres are substantially smaller and visual pigment is nearly eliminated when Drosophila are carotenoid-deprived from egg to adult. Rhabdomeres enlarge and visual pigment increases with carotenoid replacement in adults using carrot juice. We used a monoclonal antibody to the opsin in R1-6 receptors in the compound eye to further quantify opsin recovery in such carotenoid replacement therapy. Density of immunogold, specific to R1-6 (vs. R7), increases between days 1 and 3 of replacement as visual pigment and rhabdomeres recover. In summary, visual pigment, opsin and the opsin-containing organelle recover during carotenoid replacement therapy in carotenoid-deprived Drosophila.