A linear temperature gradient (26°C −33°C) was applied horizontally to a bacterial growth plate from left to right in the image. a: Representative photograph of P. putida TK1401 grown on a thermal gradient plate. Bacterial cells were incubated for 2 days on the thermal gradient plate. Line 1 is drawn through the colonies and line 2 is only drawn through the medium. b: Representative thermographs of P. putida TK1401 grown on a thermal gradient plate. c: Temperature profiles of colonies and growth medium are shown by solid and dashed lines, respectively (lines 1 and 2, respectively, in Figure 3a and b).