The effect of signal combinations differs from the sum of their effects in isolation.

<p>The expression profile of 264 QS regulated genes are plotted, comparing the sum of the individual effects of two signals (C4-HSL and 3-oxo-C12-HSL) with the effect of adding them in combination. The dotted line at 0 represents the summed null expectation and the points represent the difference between the null expectation and the effect of adding both signals. The points are coloured in black if they differ from the null expectation more than would be expected by chance (see Materials and Procedure). In 17 of these the effect of adding both signals exceeded the summed expectation and in 1 case the summed expectation exceeded the observed expression. Gene expression is normalised per gene and gene expression is given in units of standard deviation. The histogram on the right represents the distribution of differences between the null expectation (sum) and the effect of adding both signals.</p

Effect of Bald's eyesalve and its constituent ingredients on S. aureus in vitro and in vivo.

Data presented in Figs 2-5 and Fig S1 of Harrison et al, mBio 2015. Each worksheet contains a) raw data and b) annotated R code for a single figure

BiofilmCheatingData

BiofilmCheatingDat

Success of aggregates depends on shape and competition.

<p>(a) aggregate-medium interface length, s, as a function of <i>θ</i>. (b-d) Average number of progeny, <i>N</i>/<i>N</i>₀, of aggregates defined by their surface-aggregate angle <i>θ</i>, the functional from of which changes with increasing density of competitor cells: (b) <i>ρ</i> = 0 <i>μ</i>m cell⁻¹; (c) <i>ρ</i> = 0.145 <i>μ</i>m cell⁻¹; (d) <i>ρ</i> = 0.5 <i>μ</i>m cell⁻¹. Vertical bars represent the standard deviation from 20 data points.</p

Aggregate shape governs growth dynamics.

<p>Growth of the spread (<i>θ</i> = 5^<i>o</i>), semi-spread (<i>θ</i> = 90°), and rounded aggregate (<i>θ</i> = 180°) populations over the course of our simulations in the absence (<i>ρ</i> = 0 cell <i>μ</i>m⁻¹) and presence (<i>ρ</i> = 0.5 cell <i>μ</i>m⁻¹) of competition. For clarity the error bars, representing the standard deviations, are only shown for the final data points. The standard deviations at these points are maximal.</p

Aggregate shape and neighbouring strain density affect biofilm morphology.

<p>Simulation snapshots of biofilms seeded from spread and rounded aggregates after 480 h growth in the presence of a low and high density inoculum of the competing strain: (a) <i>θ</i> = 5°, <i>ρ</i> = 0.01 cell <i>μ</i>m⁻¹; (b) <i>θ</i> = 180°, <i>ρ</i> = 0.01 cell <i>μ</i>m⁻¹; (c) <i>θ</i> = 5°, <i>ρ</i> = 0.5 cell <i>μ</i>m⁻¹; (d) <i>θ</i> = 180°, <i>ρ</i> = 0.5 cell <i>μ</i>m⁻¹.</p

Rounded aggregate is relatively more successful with increased competition.

<p>Relative fitness as measured by <i>N</i>/<i>N</i>₀ of rounded aggregates increases with competition. Rounded aggregates become favourable relative to spread aggregates with increasing density of competitor cells. P values and degrees of freedom computed from unpaired two tailed T-test assuming unequal variances.</p

Initial aggregate arrangement affects biofilm morphology.

<p>Simulation snapshots of three bacterial aggregates initially arranged on the surface and the biofilms they form after 480 h: (a) Spread, 0 h. A zoomed in image is also shown to make the shape of the aggregate easier to resolve; (b) Semi-spread, 0 h; (c) Rounded, 0 h; (d) Spread, 480 h; (e) Semi-spread, 480 h; (f) Rounded, 480 h.</p

Our simulation set-up.

<p>Schematic representation of bacterial aggregates (green) which are initially spread on a surface to varying extents. The schematic also shows surrounding, competing, unaggregated cells (red). <i>θ</i> is the angle where the aggregate-medium (nutrient) interface meets the solid surface (see Section A in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0149683#pone.0149683.s001" target="_blank">S1 File</a>). Aggregates were generated from pre-formed biofilms by extracting cells whose coordinates lay within circular geometries (defined by <i>θ</i>) of varying size (see Section A in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0149683#pone.0149683.s001" target="_blank">S1 File</a>). Top- Rounded aggregate, <i>θ</i> = 180°; Middle- Semi-spread aggregate, <i>θ</i> = 90°; Bottom- Spread aggregate with <i>θ</i> = 5°. Note that the size of the aggregates (in terms of number of bacteria) is approximately equal.</p

Input parameters for biofilm simulations.

<p>Input parameters for biofilm simulations.</p