Specificity of the α-ARD antibody in Calliphora brain tissue. A Westernblot of Calliphora brain homogenates and Drosophila head homogenates with the α-ARD antibody mab 2D3. In both Calliphora and Drosophila multiple bands are observed between 42 and 50 kDa. In the Calliphora lane a band of twice the molecular weight of the ARD subunit is also visible. B Horizontal section of the visual system of Calliphora showing fluorescently labeled α-ARD immunoreativity. Immunoreactivity is almost exclusively restricted to the neuropilar regions of the medulla, lobula and lobula plate. The fibers of the inner chiasma, located between medulla, lobula and lobula plate, are immunonegative, as well as the neuronal cell bodies in the soma layer posterior to the lobula plate. C Control without the primary antibody in an adjacent section showing that the immunoreactivity is not caused by the secondary antibody. Bottom is posterior, left is lateral. ME: medulla; LO: lobula; LP: lobula plate. Scale bar: 100 μm.