INCORPORATION OF 3H-LABELLED LEUCINE INTO THE PROTEIN FRACTION IN THE RETINA OF THE HONEYBEE DRONE

Abstract— Protein synthesis in the retina of the honey-bee drone was studied by incubating head slices in labelled leucine and measuring the TCA insoluble radioactivity. It was found that the protein-bound radioactivity in illuminated retinas was half of that in dark-adapted ones. This ratio was not affected by pre-treatment with puromycin. It was therefore concluded that, in the drone, the main influence of illumination is to increase the rate of breakdown of proteins.
Relatively high concentrations of labelled protein were found in dark-adapted retinas when the retinula cells were hyperpolarized by bathing the preparation in a sodiumfree medium; low concentrations were found when retinula cells were depolarized by increasing the extracellular potassium concentration. These findings suggest that protein metabolism of the retina is influenced by the membrane potential of retinula cells.