Bm ultrascan camera

Pellets from sucrose fractions resuspended in PBS were fixed in 1% glutaraldehyde for 30 min at room temperature. Fixed samples were loaded (6 μl) on 200 mesh carbon-coated formvar copper grids (GSAU200F-50, ProSciTech), washed twice with Milli-Q water, and negatively stained with 1.5% uranyl acetate. Electron micrographs were captured with a BM-UltraScan camera (Gatan) attached to an FEI Tecnai F30 electron microscope (Bio21 Molecular Science and Biotechnology Institute, University of Melbourne) operating at a 200 kV acceleration voltage and a JEOL 1010 transmission electron microscope (Center for Microscopy and Microanalysis, University of Queensland).

For transmission electron microscopy, samples were prepared on 400-mesh carbon-Formvar-coated copper grids (Ted Pella, Redding, CA, USA). Grids were placed, carbon-Formvar down, on a 5 μL droplet of culture supernatant for 2 min. Culture supernatants were generated by centrifugation at 3000× g for 5 min. Samples were removed from the grid by wicking. Grids were then stained for 15–60 s on 5 μL of either 2% uranyl acetate stain (pH 3) or 2% sodium phosphotungstate tribasic hydrate stain (pH 6). Phosphotungstate stain was made freshly every week to ensure that the solution did not disassociate. Grids were allowed to dry in air overnight and were examined within 48 h of staining. Images were obtained at 8500 to 34,000 magnification on an FEI Tecnai F20 transmission electron microscope (TEM) (FEI Inc. Hillsboro, OR, USA). Grids were analyzed by examining randomly selected grid squares. Images were obtained with a BM UltraScan camera and stored in digital micrograph 3 (Gatan, Pleasanton, CA, USA) and TIFF formats.