Ultracut uct model ultramicrotome

The nuclear pellets, fixed in 2.5% buffered glutaraldehyde solution (pH 7.2–7.4), were then washed in 0.1 M Sorensen’s sodium phosphate buffer (SPB, pH 7.2) and postfixed in buffered 1% osmium tetroxide for 1.5 h. After several buffer washes, samples were dehydrated in an ascending concentration of ethanol leading to 100% absolute ethanol, followed by two changes in propylene oxide (PO) transition fluid. Specimens were infiltrated overnight in a 1:1 mixture of PO and LX-112 epoxy resin, and 2 h in 100% pure LX-112 resin, and then placed in a 60 °C oven to polymerize (3 days). Semi-thin sections (0.5–1.0 μm) were cut and stained with 1% Toluidine blue-O to confirm the regions of interest (via LM). Ultra-thin sections (70–80 nm) were cut using a Leica Ultracut UCT model ultramicrotome, collected onto 200-mesh copper grids and contrasted with 6% uranyl acetate, and Reynold’s lead citrate stains, respectively. Specimen were examined using a JEOL JEM-1220 transmission electron microscope (TEM, operating at 80 kV). Digital micrographs were acquired using a Gatan Erlangshen ES1000W model 785 CCD camera and Digital Micrograph software (Version 1.7).