Fig. 1: Study design.
From: Robust estimation of bacterial cell count from optical density
a Each team cultured eight strains of engineered E. coli expressing GFP at various levels: positive and negative controls plus a library of six test constructs with promoters selected to give a range of levels of expression. Each team also collected four sets of calibration measurements, b fluorescein titration for calibration of GFP fluorescence, plus three alternative protocols for calibration of absorbance at 600 nm: c dilution and growth for colony-forming units (CFU), d LUDOX and water, and e serial dilution of 0.961 μm-diameter monodisperse silica microspheres.
