FIG 8.

Compounds 3, 8, and 11 inhibit CHIKV positive-strand RNA synthesis and release of infectious virions. (A) Demonstration of concentration-dependent inhibition. Compounds (names and concentrations are shown above the panels) were added to the cells together with virus and present throughout experiment. Control cells were treated with an appropriate amount of a solvent control (DMSO). Total RNAs were extracted and separated; CHIKV positive-stand RNAs were detected using a probe complementary to the 3′ untranslated region of the virus genome. Arrows point out the positions of CHIKV genomic and subgenomic RNAs. (B) Time-of-addition assay (inhibition of positive-strand RNA synthesis). The illustration at the top represents the schema of the experiment. All compounds were used at 100 μM; samples were analyzed and results are presented as described for panel A. (C) Time-of-addition assay (inhibition of infectious virus release). The illustration at the top represents the schema of the experiment. All compounds were used at 100 μM; amounts of released virions were determined using plaque titration. Results were normalized to those from DMSO-treated control cells and expressed as log₁₀ fold reduction of infectious virus titers. Each column represents an average from two experiments performed in triplicate; error bars represent standard deviations.