Figure 1. Swimming motility and chemotaxis are required for autoaggregation.

(a–e) Aggregation of the wild-type E. coli W3110 (a), and its Δflu (b), ΔfliC (c), ΔmotA (d) and ΔcheY (e) knockouts grown to OD₆₀₀ of 0.6 at 37 °C. For aggregation experiments, cells were resuspended in fresh TB medium to OD₆₀₀ of 1.0 (two left panels) or 6.0 (right panel), and aggregation was assayed at room temperature in channels using microscopy as described in Methods. Aggregation at OD₆₀₀ of 6.0 is shown at 120 min. Scale bars, 20 μm. (f) Quantification of the area occupied by aggregates in microscopy images for the wild type and indicated mutants. Error bars indicate s.d. of three independent replicates.