Pseudomonas putida displays cyclic surface variations during growth. Plates contained LB medium (triptone 1%, yeast extract 0.5%, NaCl 0.5%, with 1% agar and supplied with 5 μm FeCl3) with Congo red (panels A-C) or Coomassie Brilliant Blue (panels D-F). Panels A, B, D, E correspond to patches grown under alternating light/darkness cycles (A and D, top view; B and E, bottom view; contrast has been enhanced for clarity). Panels C and F correspond to patches grown in constant darkness. The graphs show an extrapolation of the occurrence and duration of the differently colored rings in plates under cyclic light/darkness periods (top) or kept in the dark under the same conditions (bottom). Data are based on their width and the calculated growth rate for each patch (μm/h). Light and darkness periods are indicated below the X axis as white and grey bars, respectively. Arrow indicates when plates were removed from the cyclic light/darkness regime.
Soriano et al. Journal of Circadian Rhythms 2010 8:8 doi:10.1186/1740-3391-8-8