Cacodylate buffer

To analyse platelet ultrastructure, washed platelets were fixed with 2.5% glutaraldehyde (16,210, Electron Microscopy Sciences) in 50 mM cacodylate buffer (12,201, pH 7.2; AppliChem). After embedding in epon 812 (14,900, Electron Microscopy Sciences), ultrathin sections were generated and stained with 2% uranyl acetate (22,400, Electron Microscopy Sciences) and lead citrate (17,800, Electron Microscopy Sciences). Samples were visualized with an EM900 transmission electron microscope (Carl Zeiss).

Fat bodies were fixed in 4% formaldehyde (Science Services) and 2.5% glutaraldehyde (Merck) in 0.1 M Cacodylate buffer (AppliChem) for 48 h at 4 °C. After washing in 0.1 M Cacodylate buffer, tissues were treated with 2% osmiumtetroxid (Science Services) in 0.1 M Cacodylate buffer for 2 h. After dehydration of the sample with ascending ethanol concentrations followed by propylenoxid, samples were embedded in Epon (Sigma). Ultrathin sections (70 nm) were cut (EM-UC7, Leica Microsystems), collected onto mesh copper grids (Electron Microscopy Sciences) and contrasted with uranyl acetate (Plano GmbH) and lead citrate (Sigma). At least ten images per sample were acquired with a transmission electron microscope (JEM 2100 Plus, JEOL), a OneView 4K camera (Gatan) with DigitalMicrograph software at 80 kV at room temperature.