Fig. 1.

Optimization of 96-well based screening assay conditions. (A) Correlation of cell number and luminescence. Cell concentration of T. congolense was evaluated using the ATP-based luciferase viability assay in 100 µl assay volume per well. Fifty µl of luciferase reagent was added to 50 µl of the cell culture for evaluation. All plots were calculated from 5 independent experiments and shown as the mean luminescence signal ± standard deviation. (B) Optimization of cell culture condition. T. congolense in 1 × 10⁵, 5 × 10⁴ and 2.5 × 10⁴ cells/ml as the initial cell densities was cultured in a 96-well plate for 6 days. Trypanosome number was counted microscopically every day using a cell-counting chamber and plotted onto the graph. Each plot shows the mean number of trypanosomes ± standard deviation. (C) Estimation of trypanocidal effect of dimethylsufoxide (DMSO). Trypanocidal effect of DMSO was estimated by the ATP-based luciferase viability assay in the 96-well plate. Inhibition rate (%) was calculated from 4 independent experiments. Each column shows the mean inhibition rate (%) ± standard deviation.