Induction of a global stress response during the first step of Escherichia coli plate growth.
We have investigated the first events that occur when exponentially grown cells are transferred from a liquid medium (Luria-Bertani [LB]) to a solid medium (LB agar [LBA]). We observed an initial lag phase of 180 min for the wild type MG1655 without any apparent growth. This lack of growth was independent of the bacterial physiological state (either the stationary or the exponential phase), the solid medium composition, or the number of cells on the plate, but it was dependent on the bacterial genotype. Using lacZ-reporter fusions and two-dimensional electrophoresis analysis, we observed that when cells from exponential-phase cultures were plated on LBA, several global regulons, like heat shock regulons (RpoH, RpoE, CpxAR) and oxidative-stress regulons (SoxRS, OxyR, Fur), were immediately induced. Our results indicate that in order to grow on plates, bacteria must not only adapt to new conditions but also perceive a real stress.
Cuny
Caroline
C
Laboratoire de Chimie Bactérienne, UPR 9043, CNRS, 31, Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
Lesbats
Maïalène
M
Dukan
Sam
S
D003470:Culture Media; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response; D018384:Oxidative Stress; D020543:Proteome; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018085:Regulon
D003470:Culture Media; D029968:Escherichia coli Proteins; D020543:Proteome; D011993:Recombinant Fusion Proteins