Figure 5. Dual-fluorescence viability determination of auranofin treated schistosomula.

Mechanically-transformed schistosomula were cultured for 24 hr, incubated with different concentrations of auranofin for an additional 24 hr, washed and subsequently co-stained with both PI and FDA. PI- (544 nm, collected at 20 min) and FDA- (485 nm, collected at 5 min) fluorescence intensity units were converted into viability measures according to the formula described in the Methods . (A) Dose-dependent anti-schistosomula effect of auranofin as indicated by % viability. Treatments showing statistically significant differences in viability when compared to untreated (live) schistosomula are indicated with * (p<0.05) or ** (p<0.001). (B) Auranofin dose-response curve by which an LD₅₀ was calculated by plotting the probit transformation of the % viability to the Log₁₀ transformation of auranofin concentration. Dotted line indicates the average LD₅₀ value calculated from three replicates. (C) Light microscope image of schistosomula treated with 10µM auranofin for 24 hr. (D) Light microscope image of untreated schistosomula. (E) Epi-fluorescent and (F) plane polarized light micrograph of schistosomula treated with 10µM auranofin for 24 hr, then incubated with both PI and FDA. (G) Epi-fluorescent and (H) plane polarized light micrograph of schistosomula treated with 1µM auranofin for 24 hr, then incubated with PI and FDA. ‘Dead’ represents schistosomula killed by heat-treatment and ‘0 µM’ auranofin represents schistosomula incubated with 1% (v/v) DMSO (auranofin solvent). These results are representative of experiments performed three times.