Figure 3.

Trade-off shapes determining the behaviour of bacteria. Porins in E. coli have evolved to be neither specialist, highly permeable channels nor specialists in excluding everything including nutrients (red symbols). Most porins show intermediate, more generalist properties (circles) which may fall on different lines between the two extremes (called different trade-off shapes). Organisms O1 and O2 falling on different trade-off shapes can have very different properties. In this example, O1 is more generally fit in having the best combination of growth and resistance. The actual curvature of trade-offs is unknown for most systems, the shapes are being investigated for E. coli [47,48].