Fig. 4.

Examples of specific fluorophore uptake in E. coli BW25113. Fluorescence signals from 4 fluorophores selected from the set of 47 molecules (Table 1) with values twofold or higher above autofluorescence. The signals for all fluorophores (log₁₀ values, ordinate) are compiled against autofluorescence (orange bars) for every channel (abscissa). The light signal range for each channel is given in the Methods section. Colour-coded distributions of data by concentration of fluorophore (micromolar) are shown. The median values (log₁₀) in channel RL1 for DiSC3 and BL3 for pyronin Y are 50-fold (at 1.3 µM) and 4-fold (at 1.3 µM) above autofluorescence, respectively. In channel BL1 SYBR Green I (stock diluted 10000×) and thiazole orange (10 µM) showed log₁₀ values above autofluorescence equivalent to 3.2-fold and 4-fold, respectively. The chosen channel for each fluorophore is mapped with a black vertical arrow. Each concentration is represented by eight biological replicates taken over a period of 5 months.