1200 electron microscope

The mouse liver samples were fixed in 1% osmium tetroxide for 1 h, rinsed in distilled water, dehydrated, embedded in Spurr's resin and sectioned at 80 nm. The images were taken using a JEOL 1200 electron microscope (JEOL USA, Peabody, MA, USA).

5 mL of each peptide suspension (100 µM) was absorbed onto 200-mesh carbon-coated copper grids (Pelco, Ref: 01800 F) for 5 min and then blotted to remove excess material. Negative staining was performed by adding 5 mL of 2 % (w/v) uranyl acetate. Samples were dried on air for 3 min. The grids were imaged with a Jeol 1200 electron microscope (Jeol Ltd.) operating at a 60 kV acceleration voltage.

The four above-mentioned groups of cells were cultured in 60 mm plates, collected in a phosphate-buffered saline (PBS) solution, and fixed with 2% (v/v) paraformaldehyde (PFA, Beyotime, Shanghai, China) containing 2.5% (w/v) glutaraldehyde (Sigma, St. Louis, MO, USA) buffered in Hank’s modified salt solution (HMSS, Procell, Wuhan, China) at 4 °C for 4 h. The cells were further fixed in a 1% (w/v) OsO4 solution buffered by 0.1 M cacodylate (pH 7.2) at 4 °C for 2 h. Then, the cells were scraped off the plastic and dehydrated with dinethanol. Dehydration was conducted in propylene oxide. The specimens were embedded in an EPON medium and cut into 60–70 nm sections. The samples were analyzed and recorded with a JEOL 1200 electron microscope (JEOL Ltd., Tokyo, Japan).

Mouse eyes were enucleated following euthanasia with 5% isoflurane and decapitation. The eyes were oriented with Tissue marker dyes (Richard-Allan Scientific) and fixed in 2% paraformaldehyde; 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer for 1 hour. The anterior segment and lens was removed and secondary fixation was performed in 1% osmium tetroxide and 0.125% potassium ferrocyanide in 0.1 M sodium cacodylate buffer for 2 hours in dark followed by dehydration in a graded series of alcohol. The eyes cups were then transitioned to propylene oxide and embedded in Embed 812 resin (Electron Microscopy Sciences). Light microscope sections were cut at 0.8 μm thickness, stained with 0.1% Toluidine blue (Electron Microscopy Sciences) and photographed with Axioplan 2 upright microscope using Axiocam MRc5 digital camera and Axiovision 4.6.3 software (Zeiss). Ultrathin sections (80–90 nm) were mounted on copper grids (Electron Microscopy Sciences) and photographed with a JEOL 1200 electron microscope (JEOL).

Aggregated samples were diluted to 10 μm in Milli-Q water. 5 μl of suspension were absorbed onto 200-mesh carbon-coated copper grids for 5 min and then blotted to remove excess material. Negative staining was performed by adding 5 μl of 2% (w/v) uranyl acetate. Samples were dried on air for 3 min. The grids were imaged with a Jeol 1200 electron microscope (Jeol Ltd.) operating at a 60 kV acceleration voltage.