Thioflavine t

Thioflavine T and disperse red 13 (95%), were purchased from Sigma-Aldrich. The acetonitril (99.5%) was acquired from VWR Chemicals. The phosphorylated resveratrol (PR, 60–85%) was obtained from Ajinomoto OmniChem as a free sample and was marketed as “resveratrol triphosphate trisodium salt”. The pH was adjusted using HCl (1 N, VWR Chemicals) and NaOH (1 N, Roth). Deionized water (Millipore quality) with a resistivity of 18 MΩ cm was used. The fly food was prepared from formula 4-24 drosophila instant medium by Schlüter Biologie.

Baseline aggregation of 10 µM Tau^ΔK280 (0.46 mg/ml) was induced by adding 0.115 mg/ml heparin (4:1, Tau:heparin, [Tau^ΔK280+hep]_AGG) in the presence of 50 μM Thioflavine‐T (ThioT, Sigma‐Aldrich). To determine the seeding potential of condensates, 0.0092 mg/ml Tau or Tau^ΔK280 in form of 24 h‐old condensates (prepared with 25 µM Tau) were added to 10 µM Tau^ΔK280 in PBS, pH 7.4, 1 mM DTT (50:1, Tau^ΔK280:condensates), and 50 µM ThioT was added to detect Tau aggregation. [Tau^ΔK280+hep]_AGG plus pre‐aggregated Tau was used as a positive control. Tau^ΔK280 in PBS without heparin and PBS with ThioT alone were used as negative controls. Samples were prepared in triplicates in clear bottom 384‐well µClear plates (Greiner) and ThioT fluorescence (λ_Ex = 440 nm, λ_Em = 485 nm) was recorded at 37°C in a plate reader (Synergy H1, Biotek) every 15 min after a 5 s shake.