Additional file 1.

Figure showing molecular characterization and neurotoxic properties of the amyloid β (Aβ) preparations used in this study. (A) The preparations of Aβ were characterized in western blots probed with an anti-Aβ antibody following Bis-Tris PAGE separation (see Methods). Lane (1) shows that the stock preparation mostly contained monomeric and dimeric species, with smaller quantities of trimeric and tetrameric forms. In lanes 2 to 5, Aβ was added to 35 mm culture dishes that containing one glass polylysine coated 2 × 2 cm coverslip and 2 mL of medium at the concentrations indicated. After a three-day incubation at 37°C, aliquots of the medium were taken and resolved by electrophoresis (supernatant, snt, lanes 2 and 3). Simultaneously, the glass coverslips were washed with LDS sample buffer and the material released was also separated in the same gels (immobilized on glass, imm, lanes 4 and 5). Note that the incubation of amyloid favoured the formation of higher molecular weight forms, although most species were small oligomers and the larger aggregates, including fibrils, only represented a small fraction of the amyloid. (B) Hippocampal neurons (7 days in vitro (DIV) and 30,000 cells/cm²) were treated with Aβ as indicated. After 90 h, the cells were fixed and stained with 4',6-diamidino-2-phenylindole (DAPI) to asses the integrity of their nuclei. Note that Aβ (5 μM) produced a high rate of cell death, which justified the use of this concentration in further experiments. VF, microscope view field.

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Chacón and Rodríguez-Tébar Alzheimer's Research & Therapy 2012 4:31   doi:10.1186/alzrt134