Influence of the multicopy reporter p^{Pcib gfp} and its derivatives on expression of native <i>S</i>. Tm p2^cib-HA at the single cell level.

<p><i>S</i>. Tm p2 ^{<i>cib-HA</i>} transformed with p^{Pcib gfp} or the derivatives (p^control, p^Pcib, p^<i>gfp</i> and p^{Prpsm gfp}), respectively, were grown in LB (+ampicillin) overnight (12h; stationary phase) or subcultured for 4h in LB (late logarithmic phase) with or without indicated supplements (0.25μg/ml MitC, 100μM DTPA). Bacteria were fixed, permeabilized and intracellular ColIb-HA was detected using HA-specific antiserum and a DyLight 594-conjugated secondary antibody, DNA was stained with DAPI. Bacteria were imaged by confocal microscopy and fluorescence of DAPI, GFP and DyLight 594-conjugate was recorded. Mean fluorescence intensity (MFI) of ColIb-HA-DyLight594 <b>(A,C,E,G,I)</b> and GFP <b>(B,D,F,H,J)</b> as determined by ImageJ is shown. Dots represent MFI of individual objects (bacteria). Bars represent the median and the dotted line the detection limit (background fluorescence of <i>S</i>. Tm^wt p^control). Values indicate the fraction (%) of the population above detection limit (blue). Statistical analysis was done using Kruskal-Wallis test with Dunn's post test (* <i>p</i> < 0.05).