Figure 2: Increase of GFP intensity correlates with increased number of dynamic T6SS per bacterium. | Nature Communications

Figure 2: Increase of GFP intensity correlates with increased number of dynamic T6SS per bacterium.

From: Francisella requires dynamic type VI secretion system and ClpB to deliver effectors for phagosomal escape

Figure 2

(a) GFP signal intensities of F. novicida U112 iglA-sfGFP and fluorescence background were measured every minute for three regions of interest containing 1–30 bacteria. Two independent experiments were carried out. GFP intensity increase in a single F. novicida U112 iglA-sfGFP bacterium is shown at different time points. First image is a merge of phase contrast and GFP channels, following images represent GFP channel only. (b) Number of bacteria and T6SS structures were counted at time points between 0 and 120 min in three regions of interest containing 36–191 bacteria. Two independent experiments were carried out. Error bars represent s.d. (c,d) IglA-sfGFP localization in F. novicida U112 iglA-sfGFP wild type (c) and ΔpdpB (d). Arrowheads indicate T6SS sheath assembly and contraction. First image is a merge of phase contrast and GFP channels, following images represent GFP channel only. (e) Model for quantification of T6SS assembly position. Pole area was determined as 50% of total surface area equally distributed to both poles. (f) Model from e applied to F. novicida U112 iglA-sfGFP and V. cholerae 2740-80 vipA-msfGFP. Merge of phase contrast and GFP channels is shown. For a,c,d and f 3.3 × 3.3 μm fields of view are shown. Scale bar, 1 μm.

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