Transmission electron micrograph of Drosophila nephrocyte garland cell. Wild-type garland cells display extensive tubulo-vesicular and vacuolar profiles of endosomal compartments, including electron-lucent alpha vacuoles akin to early endosomes in the cell cortex, and electron-dense beta vacuoles that represent late endosomes more centrally. The largest vacuoles in wild type are 2 microns in diameter and all vacuoles contain a single aggregate of electron-dense granular material that appears to be attached to the limiting membrane. Samples for TEM were fixed for 1 h at 4°C in 2% paraformaldehyde, 2% glutaraldehyde, and 1% tannic acid in 0.1 M cacodylic acid buffer, pH 7.2. Then, the samples were postfixed in 1% OsO4 in 0.1 M cacodylic acid buffer, pH 7.2, for 1 h at room temperature, stained en bloc with 1% uranyl acetate, dehydrated in a grade series of ethanol and propylene oxide, and embedded in epon resin (Electron Microscopy Sciences). Blocks were sectioned in an ultramicrotome (RMC Products) at ∼70-nm thickness with a Delaware Diamond knife and post-stained for 1 h in Reynolds lead citrate and uranyl acetate. Electron micrographs were taken on a transmission electron microscope (H-7500; Hitachi) using an AMT camera system. Mag: 15000x. Image corresponds to Figure 2C, left WT panel in Kim et al. J Cell Biol. 188: 717-734. 2010. This is a high magnification view of the region in CIL# 13470.