Influence of pH and salt condition on the swimming speeds of <i>V</i>. <i>cholerae</i> Δ<i>pomAB</i> cells overproducing His₆-PomA together with PomB-Strep, PomB-S26A-Strep, or PomB-S26T-Strep.

<p>Tracks were recorded in different LB media adjusted with Tris to pH 7.0 (light grey bars), pH 8.0 (white bars), or pH 9.0 (dark grey bars). A: LB-Na⁺; B: no salt added, with residual concentrations of 11 mM Na⁺ and 12 mM K⁺; C: LB-K⁺. Tracking results of individual cells were assigned to three main classes of velocities (“slow”, “medium” and “fast”). The numbers in the bars represent the number of tracks recorded under the specified condition. The mean values and standard deviations of velocities are presented. Minimum, median and maximum values are given in the supporting information (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123518#pone.0123518.s002" target="_blank">S2</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123518#pone.0123518.s004" target="_blank">S4</a> Tables).