Effects of temperature on chemotaxis and cluster stability. (a-b) Effects of incubation temperature on swarming ability of E. coli strains. Representative swarm plates show swarm rings formed by indicated strains at 34°C (a) and 42°C (b) after 5 hours. (c) Corresponding swarming efficiency at a function of temperature for strains RP437 (filled circles), W3110 (white squares) and MG1655 (white circles). Standard errors are indicated. (d) Exchange of YFP-CheAΔ258 at receptor clusters in strain VS102 at 20°C (filled circles, data from ) and at 39°C (white squares). Means of 10 to 20 experiments are shown. Error bars represent standard errors. Grey shading is as in Figure 1. (e) Temperature effects of expression levels of chemotaxis proteins, represented here by chemoreceptors. Expression was detected by immunoblotting as described in Methods using αTar antibody that also recognizes well other chemoreceptors. In CheR+ CheB+ strains used here, each receptor runs as several bands corresponding to different states of modification. See Figure S1 for assignment of individual bands.