Fig. 5.

Expression of ComE, but not PilA, is required for the release of DNA by NTHI. Time-lapse fluorescence microscopy images of the ΔcomE mutant and the complemented ΔcomE mutant are shown. Time stamps indicate elapsed incubation time. (A) No DNA was released from the ΔcomE mutant at any time point; however, a subset of cells (dashed boxes) was uniformly red due to dye uptake. (Scale bar, 10 µm.) (A, Inset) Magnified image of a uniformly red fluorescent cell. (Scale bar, 2 μm.) (B) Complementation of the ΔcomE mutant restored the DNA flare release phenotype (dashed boxes). (Scale bar, 10 µm.) (B, Inset) Magnified image of a complemented ΔcomE mutant cell with the characteristic red flare (blue bracket). (Scale bar, 2 μm.) (C) DNA was released from ΔpilA cells via the characteristic red flare phenotype (dashed boxes), which indicated that deletion of this component of the Tfp machinery did not interfere with the described release mechanism. (Scale bar, 10 µm.) (C, Inset) Magnified image of a ΔpilA mutant cell with the characteristic red flare (blue bracket). (Scale bar, 2 μm.)