Flow chart of HTS assay.

<p>The HTS assay begins with manual preparation of working solutions of pH-MM^Suc and a bacterial suspension with OD₆₀₀ of 0.015 in PBS. Subsequent steps of the assay are fully automated: solution mixing in the 384 well-plates is performed by a ThermoScientific Matrix WellMate liquid dispenser, pin-transfer of the natural extracts tested is done with a custom-built Epson robot, and A₆₁₅ readout after incubation at room temperature is accomplished at 6 and 20 hours using an EnVision™ multi-well spectrophotometer. Finally, EnVision™ data were analyzed with Spotfire™ and Excel. Each assay is performed in duplicate. A measurement was considered to be statistically significant if it deviated by at least three standard deviations from the mean measurement calculated using all measurements made with a particular extract library. The calculated Z′ factor for the screen was 0.808±0.088.