Fig. 1. (A,B) Confocal fluorescence images of a live salivary gland incubated with 30 µmol l^–1 HAF in PS. The optical section plane through the gland tubule is indicated (upper right of each image). The broken lines in B indicate the luminal surface of the salivary gland, as deduced from background fluorescence of the cells. HAF staining is present on the basal infoldings (broad arrows) and on the lateral domain of the plasma membrane (arrowheads). Note that staining ends abruptly halfway along the lateral domain, indicating that HAF does not diffuse across septate junctions. (C) The structural organization of the secretory portion of the salivary gland. Asterisks, lumen of the gland; arrowhead, septate junction; long arrow, apical infoldings (=canaliculi); broad arrow, basal labyrinth. Bar, 20 µm.