Amyloid Beta Peptide 1-42 Monomers

Western blot of amyloid beta 1-42 monomers, oligomers and fibrils using anti-amyloid beta 6E10 antibody. Amyloid beta constructs at 160 pmol were run on 4-12% Bis-Tris SDS-PAGE, transferred to nitrocellulose in the presence of 0.02% v/v Tween-20, and blotted with 1:1000 mouse 6E10 primary antibody (Biolegend). Oligomers observed under TEM/AFM show distinct dimer/trimer bands as well as a signal from ~37-75 kDa (middle). Fibrils observed under TEM/AFM show a signal greater than 100 kDa and a distinct signal in the stacking gel (right).

TEM of amyloid beta 1-42 monomers, oligomers and fibrils . Negative stain transmission electron microscopy images acquired at 80 Kv on carbon coated 400 mesh copper grids using phosphotungstic acid and uranyl acetate stain. Scale bar = 100 nm.

AFM of amyloid beta 1-42 monomers, oligomers and fibrils . Atomic force microscopy analysis of 1.0 mg/mL samples diluted to 0.1 mg/mL in dH2O, mounted on freshly cleaved mica, washed, dried and analyzed with tapping mode. Representative images are 2.5 x 2.5 μm x-y with a z-range of 10 nm.

Amyloid beta 1-42 oligomers and fibrils show a dose-dependent toxicity to primary rat cortical neurons, but not monomers. Survival of rat primary cortical neurons 14 days after treatment with different concentrations of (A) monomers, (B) oligomers or (C) fibrils quantified by MAP2 positive neurons and expressed as a percentage of control. Fibrils and respective vehicle controls were initially sonicated in a Bioruptor. Test conditions were run in the same plate as untreated control and vehicle controls, which consisted of buffer without amyloid beta 1-42 protein. Data expressed as mean +/- s.e.m. (n=6).